Alzheimer’s

Actually I can see now that youre kinda cute.;) I dont see a lot of male lust; need more mirrors. lol
And I dont have a lot of that hetrosexual anxiety. My theory is that we are all bisexual; some deny one aspect or the other and a few dont.
Whats your take on real men take it in the ass? I dont find too amny heteros that want to talk about it. There are anatomical reasons that men would like it better than women.
You wouldnt be my first gay friend btw.


u did both complement and insult, simply by expressing natural heterosexual male anxiety at confronting the visage of toppy homosexual lust. here's a larger size version of the pic, showing off the lust better, perhaps making u more anxious...


dedda9fba6c98d4ae9ebce0ae2d87970_3.jpg




Embedded Image Unvailable
 
Actually I can see now that youre kinda cute.;) I dont see a lot of male lust; need more mirrors. lol
And I dont have a lot of that hetrosexual anxiety. My theory is that we are all bisexual; some deny one aspect or the other and a few dont.
Whats your take on real men take it in the ass? I dont find too amny heteros that want to talk about it. There are anatomical reasons that men would like it better than women.
You wouldnt be my first gay friend btw.

fair enuff, i was profiling presumptuously when reading ur post...and i've always admitted that i myself would take on BOTH Nick Lachey n Jessica Simpson...at their peaks.

as for "real" men taking it in the ass, a proper response is multipart: the prostate gland is indeed second only to the glans-frenulum in terms of erogenous sensitivity, but for many or even most men it is strongly associated with a loss of status inherently related to the pre-Human practice of anal-penetration-as-status-exchange...in many mammals, one will mount another in a display of social superiority and domination...often without penetration.

in terms of the sexual experimentation of heterosexual males, those that do choose to try being anally penetrated will very most often either do it themselves (finger, dildo) or perhaps with a female partner (finger, tongue, dildo, strap-on).

in terms of heterosexual males engaging in homosexual activity either voluntarily or involuntarily, the experience of being anally penetrated, especially by penis, is by far the most anxiety producing of possible sexual activities (outside of outlandish "kinks")...besides the non-optimality of having sex with a non-arousing partner (and while i agree most humans r bisexual to some extent, i do believe most naturally dispose more one way or another), the possibility of getting fucked tempts fear of the most cardinal possible loss-of-status fear any patriarchal society can muster: a man being "womanized".

so while i'll agree there's much pleasure men can gain by having their asses join the fun, there's many anthropological obstacles to that enjoyment...not all of them changeable.

ok, enuff threadjacking, sorry Mike!

this topic could def be its own thread in GD....
 
I totally agree.
Lemme add that I was speaking from a transactional analysis thoery of personality re. the bisexual comment. Actually there would be 12 personality aspects involved: parent-adult-child of both sexes of each person.
 
Re: TNF inhibitors (alzheimers)

It starting to make some sense now.

The Role Of Interleukin-1 In Neuroinflammation And Alzheimer Disease: An Evolving Perspective
Solomon S. Shaftel; W. Sue T. Griffin; M. Kerry O'Banion

Authors and Disclosures

Posted: 10/17/2008; J Neuroinflammation © 2008 Shaftel et al; licensee BioMed Central Ltd.

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Abstract and Introduction
Conclusion
References
Abstract and Introduction
Abstract
Elevation of the proinflammatory cytokine Interleukin-1 (IL-1) is an integral part of the local tissue reaction to central nervous system (CNS) insult. The discovery of increased IL-1 levels in patients following acute injury and in chronic neurodegenerative disease laid the foundation for two decades of research that has provided important details regarding IL-1's biology and function in the CNS. IL-1 elevation is now recognized as a critical component of the brain's patterned response to insults, termed neuroinflammation, and of leukocyte recruitment to the CNS. These processes are believed to underlie IL-1's function in the setting of acute brain injury, where it has been ascribed potential roles in repair as well as in exacerbation of damage. Explorations of IL-1's role in chronic neurodegenerative disease have mainly focused on Alzheimer disease (AD), where indirect evidence has implicated it in disease pathogenesis. However, recent observations in animal models challenge earlier assumptions that IL-1 elevation and resulting neuroinflammatory processes play a purely detrimental role in AD, and prompt a need for new characterizations of IL-1 function. Potentially adaptive functions of IL-1 elevation in AD warrant further mechanistic studies, and provide evidence that enhancement of these effects may help to alleviate the pathologic burden of disease.

Introduction
Interleukin-1 (IL-1) comprises a pleiotropic cytokine family capable of numerous actions in the central nervous system (CNS). IL-1 classically refers to a 17 kilodalton (kDa) polypeptide existing in two distinct isoforms, IL-1? and IL-1?, although other members of the IL-1 family have recently been proposed.[1] Although IL-1? and IL-1? are encoded by separate genes sharing some sequence homology, they elicit similar biological actions. In addition to these two IL-1 receptor agonists, a native IL-1 receptor antagonist (IL-1ra) also maps to the IL-1 gene cluster on human chromosome two. All three proteins are produced as precursors, of which pro-IL-1? and pro-IL-1ra possess biological activity. Pro-IL-1?, however, requires cleavage by caspase-1 (IL-1? converting enzyme, ICE) to become biologically active. Details about the structure and regulation of these family members, as well as information about many of their actions can be found in recent reviews.[2-4]

All known actions of IL-1 are mediated by a single biologically active 80 kDa cell surface receptor, the type I IL-1 receptor (IL-1RI).[5] IL-1R1 is expressed throughout the rodent brain, with levels generally highest in neuronal rich areas including the dentate gyrus, the pyramidal cell layer of the hippocampus, and the hypothalamus.[6,7] Binding of IL-1 agonists to IL-1R1 requires association with an accessory protein to elicit downstream signal transduction that includes activation of nuclear factor-kappa B (NF?B) and mitogen-activated protein (MAP) kinase pathways.[8,9] While all known biological functions of IL-1 are attributable to IL-1 interactions with IL-1R1, some studies suggest that alternate functional IL-1 receptors may exist in the CNS.[10,11]

The evolutionary importance of IL-1 activity within the brain is highlighted by the presence of two distinct endogenous regulatory pathways. IL-1ra is a competitive antagonist of IL-1R1 that selectively binds, but fails to trigger receptor association with the accessory protein resulting in blockade of all known actions of IL-1. A second 68 kDa receptor, the type II IL-1 receptor (IL-1RII), may serve as a decoy as it binds all IL-1 ligands but lacks an intracellular domain and has no demonstrated signaling function.[12] Further description of the IL-1 regulatory pathways can be found in two recent comprehensive reviews.[1,13]

IL-1 Actions Within the CNS
IL-1 was the first cytokine identified with actions on the brain.[14,15] Its ability to elicit fever after peripheral administration led to early descriptions of IL-1 as the "endogenous pyrogen". The research that followed has implicated IL-1 in a diverse array of physiologic and pathologic processes within the mammalian CNS, and has earned IL-1 status as a prototypic pro-inflammatory cytokine.[13,16,17] Generally speaking, the actions of IL-1 in the CNS are attributed to either responses of the neuroendocrine system or the local tissue microenvironment.

In response to homeostatic threats in mammals, increased IL-1 levels activate the hypothalamo-pituitary-adrenal (HPA) axis and are central to elicitation of sickness behaviors. The downstream effects of this neuroendocrine system stimulation likely underlie the ability of IL-1 to modulate processes such as appetite, body temperature, epilepsy, and sleep/wake cycles in mammals.[16,18-20] This review will focus on IL-1 as a key regulator of local tissue responses to injury and disease in the CNS, with emphasis on its role in neuroinflammation.

Expression of IL-1 in Injury and Disease
Initial evidence that IL-1 may play a key role in local brain tissue reactions came from demonstrations of elevated IL-1 expression in a diverse array of CNS diseases. In humans, IL-1 is elevated in brain tissue and cerebrospinal fluid (CSF) from patients who succumbed to brain injury or stroke.[21] This pattern of expression was further extended to animal models of CNS injury where parenchymal IL-1 mRNA and protein levels are elevated in experimental models of ischemia, excitotoxicity, infection and traumatic brain injury in rodents. While IL-1? and IL-1? are barely detectable in either normal human or rodent brain, they are rapidly induced within minutes of acute experimental injuries [reviewed in [1,3,22]].

In addition to initial demonstrations of IL-1 elevations following acute injuries, similar observations have been made in a number of chronic neurodegenerative disorders. IL-1 elevations have been reported within brain lesions from patients with Alzheimer's disease (AD), Multiple Sclerosis (MS), Down's Syndrome and HIV-associated dementia.[17,23-25] Furthermore, increased IL-1 has been detected in CSF samples in MS, Parkinson's and Creutzfeldt-Jakob disease (CJD).[26-28] These findings have since been reproduced in corresponding animal models of disease for AD, MS and CJD.[29-33]

Sources and Targets of IL-1 Expression
IL-1 is both expressed by and targeted to many different cell types within the CNS. Microglia express ICE, and in response to injury are thought to produce both the initial burst and highest levels of IL-1 production.[34] IL-1 can also be produced by astrocytes, endothelial cells, infiltrating leukocytes, neurons and oligodendrocytes.[4,35,36] In turn, IL-1 can feed back on its original cellular sources but is thought to exert its primary actions on microglia, astrocytes and endothelial cells.[2]

Neuroglia and endothelial cells produce a myriad of signaling molecules in response to IL-1 stimulation. These include pro-inflammatory cytokines, chemokines, adhesion molecules, prostaglandins, reactive oxygen species, nitric oxide, and matrix metalloproteases. Notably, IL-1 induces expression of the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-?) and Interleukin-6 (IL-6) as well as the enzyme cyclooxygenase-2 (COX-2) in both astrocytes and microglia in culture.[4,37,38] These inflammatory mediators have been implicated in the propagation of a number of CNS injuries and diseases.[39]

IL-1? and Neuroinflammation
Neuroinflammation is traditionally defined as the brain's innate immune response to injury. The hallmarks of a neuroinflammatory response are phenotypic glial activation and de novo production of immune signaling molecules. Both astrocytes and microglia undergo cellular hypertrophy with increased expression of cell-surface immune modulatory proteins, including those of the major histocompatibility complex (MHC). These changes are accompanied by increased synthesis and release of pro-inflammatory cytokines and chemokines.

IL-1? is intimately involved in elaboration of acute neuroinflammatory processes in vivo. Exposure of the rodent brain to IL-1? elicits rapid, robust activation of both astrocytes and microglia. In addition, single bolus injection or parenchymal expression of IL-1? in rodents increases expression of pro-inflammatory cytokines, leukocyte chemotactic chemokines, cell surface adhesion molecules, cyclooxygenases and matrix metalloproteases within the brain parenchyma.[40-45] Importantly, IL-1? is capable of triggering further increases in it's own expression as evidenced by murine IL-1? induction following human IL-1? administration or expression in the brain.[45,46] By feeding back upon itself, small localized elevations in IL-1 may be sufficient to drive potent neuroinflammatory changes in the brain. Further evidence for a central role of IL-1 in neuroinflammation has been provided in IL-1R1 knockout mice where lack of IL-1 signaling in the setting of penetrating brain injury causes dramatic attenuation in microglial and astrocytic activation as well as IL-6 and COX-2 production.[47,48]

IL-1 and Leukocyte Recruitment
In addition to elaboration of a robust neuroinflammatory response in the CNS, IL-1 elevations have been implicated in trafficking of peripheral immune cells to the brain. The normal, healthy CNS has relatively few, if any leukocytes.[49] However, cellular populations within the brain can quickly change following injury. The inflammatory response that follows CNS insults such as infection or injuries caused by trauma or ischemia often features rapid infiltration of leukocytes into the brain.[50-52]

IL-1? expression is a powerful stimulus for leukocyte recruitment to the CNS. Either single bolus injection or localized expression of IL-1? within the rodent brain is capable of overriding the brain's intrinsic resistance to leukocyte recruitment, resulting in rapid cellular infiltration of the parenchyma. Cell types recruited include neutrophils, CD4+ and CD8+ T-cells, dendritic cells, and cells of the monocyte lineage.[40,43,44,46,53,54] This leukocyte infiltration is dependent on IL-1R1, and can be significantly reduced following administration of IL-1ra.[44,53,55,56] The ability of IL-1? to drive enhanced expression of monocyte chemoattractant protein-1 (MCP-1; CCL2) by astrocytes and intercellular adhesion molecule-1 (ICAM-1) on vascular endothelial cells within the brain is thought to facilitate parenchymal cellular recruitment.[40,44] Indeed, adenoviral overexpression of IL-1ra following experimental ischemia reduces ICAM-1 expression and leukocyte infiltration of the brain.[57]

Neutrophils play a vital role in the innate arm of the immune response that rapidly develops at sites of injury and infection. While primarily recognized for destruction of invading pathogens, neutrophils can also shape immune responses.[58] The chemokines of the ELR+ CXC family are potent stimuli for the recruitment and activation of neutrophils in peripheral and CNS inflammatory responses, and are upregulated by acute IL-1? stimuli.[59-63] In mice, the most potent and well defined members of this family are keratinocyte-derived chemokine (KC, CXCL1) and macrophage inflammatory protein 2 (MIP-2, CXCL2) which are thought to signal exclusively through the CXCR2 receptor.[50,60,63-65] Interestingly, chronic IL-1? expression can serve as a long-lasting stimulus for MIP-2 and KC induction as well as neutrophil recruitment to the brain. Using a mouse model of chronic hippocampal human IL-1? overexpression, we observed neutrophil infiltration of the brain parenchyma months after initiation of transgene activation. This neutrophil recruitment appeared to be dependent on signaling through the CXCR2 receptor, as it was absent in CXCR2 knockout mice.[44]

Leukocyte recruitment to the CNS is highly restricted by presence of the blood-brain barrier (BBB), which is credited for the virtual absence of leukocytes within the healthy brain parenchyma.[66] Although not thought to be necessary nor sufficient for leukocyte infiltration of the CNS, breakdown of the BBB is believed to potentiate cellular recruitment to the brain.[49] Experimentally induced elevations of IL-1? levels in the brain cause disruptions in the BBB, which may underlie its effectiveness as a leukocyte recruitment stimulus.[41,43,44,54] Neutrophils have been implicated in mediating this effect based on a study in rats where administration of anti-CINC-1 (CXCL1) neutralizing antibodies attenuated neutrophil recruitment and BBB breakdown downstream of intracerebral IL-1? injections.[41] However, recent work in our laboratory indicates that IL-1? can influence BBB integrity even in the relative absence of neutrophil recruitment. More specifically, we observed significant leakage of albumin bound Evan's blue dye into the brain parenchyma of mice engineered to chronically express human IL-1? in a sustained manner, which was not altered in animals lacking the CXCR2 receptor.[44] The precise mechanisms of IL-1? mediated changes in BBB permeability remain unclear. Further studies are needed to elucidate this phenomenon, as it may be important in the pathogenesis of CNS injury and disease.

Learning, Memory, and IL-1
In addition to its role in elaboration of neuroinflammation and leukocyte recruitment, local expression of IL-1 has been implicated in impairment of hippocampal dependent memory processing.[67] IL-1? activity is thought to be closely tied to the process of memory consolidation based on demonstrations of increased IL-1? expression in vitro and in vivo during long-term potentiation (LTP), a process that is believed to underlie hippocampal dependent learning and memory processes in mammals.[68] At sufficient concentrations, IL-1? is capable of blocking hippocampal LTP.[69] Also, injection of lipopolysaccharide (LPS), a potent inducer of IL-1? expression by microglia, into the rat hippocampus results in learning and memory deficits.[70] Conversely, blockade of IL-1R1 in rats using adenoviral expressed IL-1ra leads to facilitation of short and long-term memory in an inhibitory avoidance task.[71] Based on these data, it is feasible that IL-1 elevations, as occur following CNS injuries and during neurodegenerative disease, might lead to impairments in learning and memory. This may help explain the prominent memory deficits characteristic of AD and HIV-associated dementia.

The Contribution of IL-1 to Acute CNS Injury
The elevation of IL-1 expression following a diverse array of acute brain injuries coupled with its ability to elicit diverse inflammatory changes as previously discussed, suggests that it may contribute to the pathogenesis of CNS injury. Indeed, data from head injury victims as well as in acute experimental brain injury paradigms has provided strong evidence in support of this.[21] To date most studies have focused on the CNS actions of IL-1?, rather than IL-1?, based on its more rapid induction following injury.[16] A number of studies have demonstrated that administration of IL-1? concurrent with experimental ischemia is capable of exacerbating injury.[1,72] Conversely, ischemic damage is greatly reduced by knockout of IL-1? and IL-1?, administration of IL-1 blocking antibodies, or disruption of interleukin-1 converting enzyme function.[2,73,74] Interestingly, there is some evidence that IL-1 may influence ischemic injury independent of IL-1R1.[11] In traumatic brain injury, neuronal damage is similarly reduced by administration of IL-1ra.[75] Based on the ability of exogenously administered IL-1ra to attenuate experimental ischemic injury and cross the BBB, therapy with human IL-1ra has been investigated in a Stage II clinical trial of stroke.[76-78]

Increased levels of endogenous IL-1ra and IL-1RII are likely to be important mechanisms for regulation of IL-1 activity following brain injury. IL-1ra is rapidly induced following experimental injury, and blockade of endogenous production leads to exacerbation of neurotoxicity following ischemic injury in rodents.[74,79] Increased expression of IL-1RII, the biologically inactive "decoy" IL-1 receptor, has been demonstrated following injection of IL-1? into the brain parenchyma and may also serve to limit the biological function of IL-1.[12]

In addition to data implicating IL-1 in exacerbation of acute injury, other studies have provided evidence for beneficial effects of IL-1 signaling within the brain. IL-1 has been associated with neuroprotective mechanisms in rodent primary neuron cultures which may be mediated in part by production of survival signals such as nerve growth factor (NGF).[80-82] IL-1 signaling has also been implicated in re-myelination of the CNS after cuprizone demyelination injury, which may be due in part to IL-1 mediated stimulation of oligodendrocyte proliferation.[35,83] Finally, absence of IL-1R1 has been associated with deficiencies in hippocampal dependent spatial learning but it is unclear if this is a result of specific beneficial influences of IL-1 on the intact nervous system or represents developmental alterations in the knockout mouse.[84]

Mechanisms of IL-1 Induced Neuronal Damage
Due to its pleiotropic actions in the brain it has been difficult to pinpoint the mechanisms by which IL-1 exacerbates acute CNS injuries. In general, it does not appear that IL-1? is capable of triggering direct neurotoxicity when administered to the healthy adult rodent brain.[16] For example, chronic hippocampal overexpression of human IL-1? in mice does not engender overt neurotoxicity or changes in measures of neuronal integrity.[44] In rats, IL-1? induced neurotoxicity has been reported following single bolus injection or adenoviral mediated expression of IL-1? in the substantia nigra or hippocampus, respectively.[46,85,86] However, these studies in rats may have been confounded by tissue injury resulting from parenchymal injections, viral induced inflammation, or the use of non-physiologic doses of IL-1?. It is also possible that the capacity of IL-1? to mediate direct neurotoxicity may be a species-specific phenomenon. In vitro, IL-1? exposure does not affect the viability of pure mouse or rat neuronal cultures and can reduce excitotoxin induced neurotoxicity.[81,82] However, in rat mixed glial/neuronal cultures IL-1? has been reported to cause neurotoxicity through downstream free radical release.[87]

Neutrophils have emerged as possible perpetrators of neuronal damage following acute brain insults downstream of IL-1? elevations.[40,41,43,53] Neutrophils are rapidly recruited following CNS injury, present at the time of neuronal death, and can trigger tissue damage through generation of toxic free radicals, proteolytic enzymes and pro-inflammatory cytokines such as IL-1? and TNF-?.[52] In vitro, co-cultures of rat neutrophils and primary hippocampal neurons demonstrate neurotoxicity in the absence of physiologic insults as well as exacerbation of kainic acid excitotoxicity.[88] In vivo, constitutive CNS overexpression of the chemokine KC results in striking recruitment of neutrophils to multiple brain regions and early neurological demise.[89] Depleting neutrophils or limiting their infiltration through ICAM-1 gene ablation attenuates experimental ischemic injury.[52,90] Despite these observations, recruitment of neutrophils does not appear to be sufficient for neurotoxicity. This point is supported by recent work from our laboratory where no evidence of overt neurotoxicity, synaptic damage, or loss of acetylcholine fibers was observed after 2 weeks or 2 months of sustained IL-1? induced neuroinflammation accompanied by prominent neutrophil infiltrates.[44] However, this study was limited to neuroinflammation in the dentate gyrus in the absence of concomitant injury, and it is possible that neurons in other brain regions may be more susceptible to neutrophil-mediated effects.

Neuroinflammation and AD
Neuroinflammation is now recognized as a fundamental response of the CNS not only to acute injury, but also to chronic neurodegenerative disease. This is perhaps no better demonstrated than in AD, where the severity of the neuroinflammatory response parallels the disease course.[91,92] Neuroinflammation can be considered part of a characteristic pathologic triad of AD that includes amyloid plaques and neurofibrillary tangles. The neuroinflammatory phenotype in AD is characterized by robust activation of microglia and astrocytes in the vicinity of plaques, endogenous expression of pro-inflammatory cytokines, cell adhesion molecules, and chemokines.[17,93-96] These changes are thought to result from glial reaction to events related to ongoing deposition of amyloid ? (A?).[97-99]

Epidemiological studies of nonsteroidal anti-inflammatory drug (NSAID) users lent credence to initial hypotheses as to the role of neuroinflammation in AD. Early observations among identical twins discordant for AD onset showing that those receiving anti-inflammatory therapy had delays in disease onset provided strong evidence for a detrimental role of neuroinflammation in AD pathogenesis.[100] Soon thereafter, additional case-based and longitudinal epidemiologic studies confirmed these findings, and demonstrated substantial reductions in disease incidence among patients on long-term regimens of NSAIDs.[101-103] In fact, recent meta-analysis has revealed as much as a 50% reduction in the risk of acquiring disease among chronic NSAID users.[104] This data led to a surge of research activity directed at elucidating the role of inflammation in AD and other chronic neurodegenerative disorders in hopes of designing new effective anti-inflammatory therapies for disease.

Unfortunately, clinical trials of traditional anti-inflammatory agents for treatment of patients with AD have failed to demonstrate efficacy.[105-110] Also, the only trial designed to directly address the hypothesis that chronic NSAID use can prevent AD in cognitively normal subjects failed to demonstrate a protective effect.[111] Drawing conclusions from these studies is complicated by the selection and dose of NSAIDs used, length of trials and overall designs.[112] Furthermore, the patient populations in these trials differ from their epidemiologic counterparts as patients in the latter were being treated with NSAIDs for inflammatory disorders which may have modified their risk of acquiring AD. Overall, the stark contrast between these results and the early epidemiological studies of chronic NSAID users suggests a complex role for neuroinflammation in AD.

Transgenic mouse models of AD harboring familial amyloid precursor protein (APP) mutations have recapitulated in part the intimate relationships between neuroinflammation and disease pathogenesis. In APPV717F mice astrocyte activation was evident before plaques were detected, and in the Tg2576 mouse model increased microglial density was observed in regions of A? deposits.[113,114] Similar neuroinflammatory changes have been observed in other murine models of AD, including the APP/PS1 double transgenic and APP/PS1/Tau triple transgenic (3xTg-AD) mice.[115-117] Finally, NSAID administration reduced both plaque pathology and neuroinflammatory measures in the Tg2576 mice.[32]

Possible Roles for IL-1 in AD
IL-1 elevations became closely tied to AD pathogenesis soon after the discovery of prominent neuroinflammation in AD brain. Increased IL-1 expression in reactive microglia surrounding amyloid plaques provided the initial indication that IL-1 may be associated with AD pathogenesis.[17] Since that time, IL-1? elevations have been detected in the brains of aged AD mouse models and plaque associated microglia.[31,32] Microglial IL-1 activity was later tied to the evolution of plaques in AD.[118] In Down's syndrome, where patients are predisposed to AD neuropathological changes, IL-1 elevation and neuroinflammation precede by years the formation of plaques.[119] Additionally, specific polymorphisms in the IL-1? and IL-1? genetic loci were shown to be associated with increased disease risk in certain patient populations [reviewed in [120,121]]. These associations, in addition to observations of IL-1 elevations in AD patients, provided the key evidence for a central role of IL-1 in disease pathogenesis. However, recent meta-analysis has not supported a clear association between IL-1 genetic loci and AD when the data is examined as a whole.[122]

IL-1 has been implicated in both the initiation and propagation of neuroinflammatory changes seen in AD through several lines of indirect evidence [reviewed in [39,123]]. Obviously, the known ability of IL-1 to drive robust neuroinflammatory changes in the acute setting adds to its attractiveness as a prime candidate for these actions. In AD, neuronal injury or insults including amyloid deposition may trigger a self-propagating cytokine cycle, which when chronically induced initiates a vicious feedback loop of continuing IL-1? elevation promoting further neuronal and synaptic dysfunction and A? plaque accumulation.[99] In support of this idea, cultured human monocytes and mouse microglia produce IL-1? in response to A? exposure or, to a greater extent, to secreted fragments of ?-APP.[124,125] In other tissue culture studies IL-1 has been shown to increase ?-APP mRNA expression, translation, and processing perhaps through enhanced gamma secretase activity.[126-130] In addition, IL-1? injection into rat brain results in elevation of ?-APP.[131] Furthermore, IL-1ra knockout mice demonstrate enhanced human amyloid-beta induced neuropathology, suggesting the unopposed action of IL-1 as a likely culprit.[132] Although these findings are largely in vitro based, correlations in Alzheimer and control patients support the idea that these basic mechanisms occur in the disease itself.

In addition to association with modulation of ?-APP processing, IL-1 activity has been tied to exacerbation of neurofibrillary tangles. Implantation of slow release IL-1? pellets in rats led to microglial activation and MAPK-p38-mediated hyperphosphorylation of tau protein, which is thought to contribute to microtubule destabilization and ultimately to formation of neurofibrillary tangles.[133,134] Analogous studies have been reported in cortical neuron cultures.[135] Microglial activation may be responsible for these effects as suggested by a recent study of synapse loss in a mouse tauopathy model.[136] Further support for IL-1? mediated activation of microglia and resultant tau hyperphosphorylation has been indirectly provided in the 3xTg-AD mouse model which expresses human mutated forms of tau, presenilin-1 and APP, and is characterized by both A? and tau pathology. Intraperitoneal LPS injections elicited significant IL-1? induction, microglial activation and accelerated the time course of tau hyperphosphorylation. Interestingly, LPS activity did not affect APP processing or A? deposition.[137]

A Beneficial Role for Neuroinflammation in AD
While epidemiologic and experimental studies lend strong support for neuroinflammatory responses as drivers of AD pathogenesis, recent work also supports a beneficial role for such reactions [reviewed in [98]]. A number of reports have provided evidence that activation of microglia and their subsequent degradation of amyloid plaques may underlie this phenomenon. Direct injection of LPS into the CNS, which drives IL-1? synthesis and robust microglial activation, yields reductions of A? levels and plaque load.[138-140] Microglial activation has also been suggested to underlie enhanced plaque clearance in other transgenic AD models following treatment with either a modified nitric oxide-releasing NSAID (NCX-2216) or transforming growth factor beta overexpression (TGF-?).[141,142] Conversely, inhibition of microglial activation with minocycline can increase A? deposition.[143] Although these reports and others suggest a beneficial role of microglial activation in mouse models of AD, it is worth noting that LPS stimulated neuroinflammation has also been associated with increased A? deposition.[144,145]

Microglial activation is thought to reduce plaque burden through phagocytosis of A? peptides. There is substantial evidence for plaque associated microglia as phagocytosing scavengers of amyloid in vivo.[146] Indeed, the efficacy of antibody-mediated plaque clearance in AD mouse models appears in part to be mediated by enhanced phagocytosis by microglia.[147,148] In support of this, interference with microglial activation during A? immunotherapy reduced clearance of fibrillar deposits.[149]

Infiltration of peripheral immune cells into sites of pathology, though not reported in AD itself, may enhance the beneficial effects of microglial mediated plaque clearance. It has been convincingly demonstrated, using green fluorescent protein (GFP) expressing bone marrow transplants in AD mouse models, that a proportion of activated microglia adjacent to amyloid plaques are in fact recruited from bone marrow-derived myeloid populations.[150,151] LPS administration enhances the seeding of bone marrow-derived myeloid cells in the brain which may in part explain its ability to enhance amyloid plaque clearance.[150] Selective elimination of bone marrow-derived myeloid cells exacerbates plaque pathology in AD models, and providing strong evidence that this microglial sub-population is efficient at degrading plaque.[151,152] Interestingly, an infiltrative cell type with dendritic cell-like characteristics appears to be particularly important in this process.[153] Taken altogether, these results suggest that the beneficial effects of neuroinflammation may in part result from increased recruitment of bone marrow-derived cells to the brain.

A New View of IL-1's Role in AD?
Since the original observations of IL-1 elevation in AD two decades ago, a body of evidence has implicated this proinflammatory cytokine as contributing to the pathogenic processes characteristic of disease. Much of this data has relied on indirect evidence and extrapolation from studies in tissue culture and acute injury paradigms. As is the case for neuroinflammation, contemporary studies in animal models of AD are challenging our original assumptions as to the role of IL-1 in AD.

Substantial support for an adaptive role of IL-1 elevation comes from a model developed in our laboratory to specifically address the function of chronic IL-1 driven neuroinflammation in AD pathology. When IL-1? was chronically overexpressed in the hippocampus of APP/PS1 transgenic animals, we witnessed a surprising reduction in both plaque pathology and insoluble amyloid peptide without evidence of effects on A? processing or APP expression. There was also a striking increase in numbers of plaque associated myeloid cells, suggesting enhanced phagocytosis of A? by microglia or infiltrating myeloid cells.[45] A limitation of this study is the use of a heterologous APP promoter, as this does not allow for interplay between inflammation and the APP promoter as discussed earlier. However, IL-1? overexpression was not associated with increased levels of murine APP mRNA.[45]

The initial stimulus for elevation of IL-1 in AD is likely the result of exposure of microglia to injured neurons, ?-APP, and its cleavage product A? as has been demonstrated both in vitro and in vivo.[125,151] Microglia chronically exposed to these stimuli during the course of disease likely mount sustained elevations in IL-1 and drive a self-perpetuating cycle of IL-1 overexpression in the brain parenchyma leading to chronic neuroinflammation.[45] As highlighted above, IL-1 elevation may potentiate plaque degradation by enhancing microglial activation and phagocytic activity, as well as seeding of peripheral phagocytic cells to areas of plaque deposition.[44] Despite this evidence pointing toward an important function of IL-1 in AD pathogenesis, a recent study in the Tg2576 AD mouse model failed to detect any influence of IL-1R1 knockout on either A? deposition or the efficacy of passive immunotherapy.[154] However, these results must be interpreted with caution as IL-1R1 knockout animals may be affected by compensatory changes during development.

At the present time our understanding of the relationship between neuroinflammation, IL-1, and AD is evolving. The downstream consequences of IL-1 elevation in AD likely involve a balance between the beneficial and detrimental functions highlighted in this review (Figure 1). Failures of recent anti-inflammatory trials in the treatment of AD may be in part explained by blockade of both beneficial and detrimental neuroinflammatory processes in the course of disease. Current findings are consistent with the idea that strategies aimed at enhancing beneficial components of neuroinflammatory pathways in chronic neurodegenerative disease may hold promise in the development of new therapies.
 
Insights Give Hope for New Attack on Alzheimer’s
http://www.nytimes.com/2010/12/14/health/14alzheimers.html?_r=1

December 13, 2010
By GINA KOLATA

Alzheimer’s researchers are obsessed with a small, sticky protein fragment, beta amyloid, that clumps into barnaclelike balls in the brains of patients with this degenerative neurological disease.

It is a normal protein. Everyone’s brain makes it. But the problem in Alzheimer’s is that it starts to accumulate into balls — plaques. The first sign the disease is developing — before there are any symptoms — is a buildup of amyloid. And for years, it seemed, the problem in Alzheimer’s was that brain cells were making too much of it.

But now, a surprising new study has found that that view appears to be wrong. It turns out that most people with Alzheimer’s seem to make perfectly normal amounts of amyloid. They just can’t get rid of it. It’s like an overflowing sink caused by a clogged drain instead of a faucet that does not turn off.

That discovery is part of a wave of unexpected findings that are enriching scientists’ views of the genesis of Alzheimer’s disease. In some cases, like the story of amyloid disposal, the work points to new ways to understand and attack the disease. If researchers could find a way to speed up disposal, perhaps they could slow down or halt the disease. Researchers have also found that amyloid, in its normal small amounts, seems to have a purpose in the brain — it may be acting like a circuit breaker to prevent nerve firing from getting out of control. But too much amyloid can shut down nerves, eventually leading to cell death. That means that if amyloid levels were reduced early in the disease, when excess amyloid is stunning nerve cells but has not yet killed them, the damage might be reversed.

Yet another line of research involves the brain’s default network: a system of cells that is always turned on at some level. It includes the hippocampus, the brain’s memory center, but also other areas, and is the brain’s mind-wandering mode — the part that is active when, for instance, you’re driving in your car and you start thinking about what you will make for dinner. That brain system, scientists find, is exactly the network that is attacked by Alzheimer’s, and protecting it in some way might help keep the brain healthier longer.

For example, during nondreaming sleep, the default network is thought to be less active, like a light bulb that has been dimmed. The network also ramps down during intense and focused intellectual activity, which uses different areas of the brain. One emerging theory suggests that if the default network can be rested, amyloid production might be decreased, allowing even an amyloid disposal system that was partly hobbled by Alzheimer’s to do a better job.

The result of all this work is a renewed vigor in the field. After years in which it was not clear how to attack this devastating disease, scientists have almost an embarrassment of riches. The research is in early stages, of course, and there are many questions about which discoveries and insights will lead to prevention or a treatment that works.

But there is a new hopefulness that, at long last, this terrible disease may eventually be conquered, said Richard Mohs, Alzheimer’s group team leader at Eli Lilly.

“We are much closer and quite optimistic that we will be able to do it,” Dr. Mohs said.

A Key Question

When Dr. Randall Bateman first tried to get funds for an effort to answer a sort of chicken-and-egg question about Alzheimer’s, some grant reviewers turned him down, saying they doubted it would work. But they were wrong. He got his answer, although it took much longer than he expected, and his paper describing his results was just published online Thursday by Science.The question came to him in 2003, when he was a neurology resident. One day he was sitting in the hospital cafeteria at Washington University in St. Louis, taking advantage of free soup and rolls. Dr. David M. Holtzman, a neurology professor, joined him, and the two began to talk about the puzzle of Alzheimer’s. Why, Dr. Bateman wondered, did beta amyloid build up in patients’ brains? Were people making too much? Or were they unable to dispose of what they made?

Great question, Dr. Holtzman replied, but what kind of test could you do to answer it?

Dr. Bateman pondered the issue for a year and finally figured out a method. It would not be easy — study subjects would have to sit around for 36 hours with a catheter in their spinal column collecting cerebrospinal fluid. “I said, ‘I think I can probably develop and do this in about six months,’ ” he told Dr. Holtzman.

Dr. Holtzman had his doubts.

“I thought his idea could work conceptually, but for everything to work just right in a human being was a long shot,” he said.

Dr. Bateman’s plan was to put a catheter into a person’s vein and infuse an ingredient, the amino acid leucine, that cells need to make beta amyloid.

The infused leucine would be chemically modified with a form of carbon that did not affect its function or safety but that made it easy to detect newly made amyloid as it was flushed out into the spinal fluid. And since he knew how much leucine he gave people, he could measure how much amyloid they made and then see how fast it was drained.

When the study began, Dr. Bateman was his own first subject. He then did the test on people in their 30s and 40s, as well as healthy older people and people with Alzheimer’s.

He finally completed the study, getting his answer in seven years, rather than the six months he had naïvely expected.

The problem in Alzheimer’s, he found, is disposal. Beta amyloid, he found, normally is disposed of extremely quickly — within eight hours, half the beta amyloid in the brain has been washed away, replaced by new beta amyloid.

With Alzheimer’s disease, Dr. Bateman discovered, beta amyloid is made at a normal rate, but it hangs around, draining at a rate that is 30 percent slower than in healthy people the same age. And healthy older people, in turn, clear the substance from their brains more slowly than healthy younger people.

That means that it might be possible to attack Alzheimer’s not just by getting rid of beta amyloid but also by speeding its disposal. And, he says, there is a clear message in his results.

“What we think may be happening is that a clearance mechanism is broken first,” Dr. Bateman says. Slowly, as years go by, beta amyloid starts to accumulate in the brain. If that clearance can be fixed, or enhanced, the buildup might never occur.

Beta Amyloid as Signal Control

For years, Alzheimer’s researchers wondered if the brain used small molecules of beta amyloid or if those fragments, produced when a larger protein is snipped, were more like scraps of fabric, serving no purpose and just getting in the way.

Now, some say they may have an answer. Beta amyloid, in small quantities, seems to control signaling between nerve cells, reducing the strength of signals when they are too strong. But when it accumulates, the brain can have too much of a good thing. Nerve impulses can be stopped dead, nerves can die, and the disease can take hold, according to this idea.

The work leading to this conclusion began a few years ago when Dr. Roberto Malinow of the University of California, San Diego, decided to look at whether beta amyloid affects synapses, the functional connections between nerve cells. Electrical signals are transmitted through synapses as they travel from nerve cell to nerve cell. And nerve cells make beta amyloid and release it onto their synapses. Was it doing anything there?

One way to find out, Dr. Malinow reasoned, would be to genetically engineer nerves to overproduce beta amyloid and determine what happened to their signaling in laboratory experiments.

The signals, he found, were muffled.

As Dr. Malinow and his colleagues inquired further they discovered that beta amyloid seemed to be part of a nerve cell feedback loop. A nerve will start firing, but under some conditions, the signal can get too intense. Then the nerve releases beta amyloid, bringing the signaling down to normal levels, at which point the nerve stops releasing beta amyloid.

The impact of beta amyloid on synapses was “a very clear effect,” at least in the lab, Dr. Malinow said.

“We proposed that maybe a-beta was normally part of a negative feedback system,” Dr. Malinow said, using a shorthand reference to beta amyloid.

The damage — and Alzheimer’s disease — comes in if there are too many clumps of beta amyloid in the brain. When that happens, the signals between nerve cells are reduced too much, effectively stopping communication.

“Too much of a good thing is bad,” says Dr. Dennis Selkoe, a professor of neurologic diseases at Harvard Medical School. Still, treatment at that point, before the nerves are dying, might reverse the disease.

There may be another way to protect nerves from too much beta amyloid, and it involves a different protein linked to Alzheimer’s. Problems with it show up in the brains of Alzheimer’s patients later, after there has already been a buildup of beta amyloid.

The protein is tau, an integral part of normal cells. It becomes tangled and twisted in Alzheimer’s, after cells are already dying, looking like strands of tangled spaghetti. For decades researchers have argued about whether those distorted tau molecules were a cause or an effect of nerve cell death. Now, they believe they may have an answer, which is spurring the search for drugs to salvage tau and protect the brain from beta amyloid.

New studies by Dr. Lennart Mucke, a neurology professor at the University of California, San Francisco, and director of the Gladstone Institute of Neurological Disease there, and others suggest that tau facilitates beta amyloid’s lethal effects. In genetically engineered mice and in laboratory experiments, the researchers found that without tau, beta amyloid cannot impair nerve cells.

If tau also plays the same role in the brains of humans, that might resolve a longstanding mystery. Occasionally, in autopsies pathologists find that people who had normal memories had lots of plaques in their brains. Perhaps those people, for some reason, made very little tau or were naturally resistant to the injurious interaction between tau and beta amyloid. Could that be why they somehow endured a buildup of beta amyloid?

“That’s a very interesting question,” Dr. Mucke said. “We don’t know the answer.” But, he adds, researchers “should try to learn from such cases how to better fight the disease.”

Early Detection Crucial

In order to treat Alzheimer’s before it is too late, scientists now believe they have to detect it much earlier, before there are symptoms. To do that, they have developed several new methods, including brain scans that can show amyloid plaques in living patients. And for Dr. Marcus E. Raichle, a neurologist at Washington University, what the scans showed was a revelation.

“I was absolutely struck by where this stuff was accumulating in the brain,” he said.

Amyloid was in exactly the areas he was studying, the default network. It is used not only in daydreaming but in memory and in the sense of self. For example, if a man is shown a list of adjectives — honest, kind, thoughtful — and asked if they reflect the way he thinks of himself, the man will use his default network.

“It seems to be a target of Alzheimer’s disease, which I found stunning,” Dr. Raichle said.

The entire default network, and only the default network, was under attack.

The default network is costly for the brain to run, using huge amounts of glucose, Dr. Raichle said. And one indication that a person is getting Alzheimer’s is that in scans, the brain’s glucose use is markedly lower. The observation that Alzheimer’s attacks the default network, then, explains the observation that a low use of glucose by the brain is associated with Alzheimer’s disease.

“The default network has a unique metabolic profile,” Dr. Raichle said. “That opens up a whole set of biological questions about how these synapses are operating.”

“Why does Alzheimer’s attack that region?” he asked. “The simple answer is, we don’t know.”

Meanwhile, Dr. Holtzman was doing a different sort of experiment that turned out to bear directly on what Dr. Raichle was finding.

He found a way to measure amyloid levels in the brains of living mice. He would drill a small hole in each one’s skull and insert a probe that allowed beta amyloid to be collected.

Dr. Holtzman kept the probes in while the animals were eating and running around their cages and when they were sleeping. Beta amyloid synthesis increased when they were awake, when the default network is most active, and decreased when they slept.

His colleagues, Dr. David Brody at Washington University and Dr. Sandra Magnoni of Milan University, then devised an experiment in people. Their subjects were in comas following head trauma or strokes. Often, doctors drill a small hole in these patients’ skulls and insert a catheter to monitor fluids in the brain. Dr. Brody and Dr. Magnoni asked if they could also measure beta amyloid.

They found that the less active the person’s brain, the less beta amyloid it made. That made the researchers ask whether something similar was happening during sleep — the default network was less active, so perhaps less beta amyloid was being made. If so, the implication, which Dr. Holtzman is studying, is that people who are sleep-deprived might be at greater risk of Alzheimer’s.

Another question is whether, as observations have suggested, people with more education are less prone to develop Alzheimer’s disease. Dr. Holtzman’s hypothesis is that education, by encouraging more deliberate problem-solving and thought, decreases the activity of the default network, which is not highly engaged with such focused activity.

At this point, with so many threads of research pointing to so many ideas about Alzheimer’s, everything is a target for treatments to prevent or slow the disease — enhancing the brain’s beta amyloid disposal system, interfering with nerve cells’ feedback loops, blocking tau, protecting the brain’s default network by focusing on its unique metabolic properties.

But researchers say the best hope for the immediate future is with experimental drugs, now being tested, that slow beta amyloid production. The hope is that if the flow of amyloid into the brain is slowed, levels can go down even if the amyloid drain is slightly clogged. The drugs might work even if the problem is with the drain, not the faucet.

The trick in Alzheimer’s, though, might be to start treatment before too much damage is done.

And, said Dr. Samuel E. Gandy, a neurology professor at Mount Sinai School of Medicine, there are some big questions that will have to be answered soon.

“The question for the amyloid folks is, How early is early enough to start treatment? How long is long enough to treat? And what are the other targets we should be attacking?”

But for now, Dr. Holtzman says, the new findings are offering hope.

“We have a richer view of the genesis of Alzheimer’s disease as well as new directions for research, prevention and treatment,” he said.
 
Early Tests for Alzheimer’s Pose Diagnosis Dilemma
http://www.nytimes.com/2010/12/18/health/18moral.html

December 17, 2010
By GINA KOLATA

Marjie Popkin thought she had chemo brain, that fuzzy-headed forgetful state that she figured was a result of her treatment for ovarian cancer. She was not thinking clearly — having trouble with numbers, forgetting things she had just heard.

One doctor after another dismissed her complaints. Until recently, since she was, at age 62, functioning well and having no trouble taking care of herself, that might have been the end of her quest for an explanation.

Last year, though, Ms. Popkin, still troubled by what was happening to her mind, went to Dr. Michael Rafii, a neurologist at the University of California, San Diego, who not only gave her a thorough neurological examination but administered new tests, like an M.R.I. that assesses the volume of key brain areas and a spinal tap.

Then he told her there was something wrong. And it was not chemo brain. It most likely was Alzheimer’s disease. Although she seemed to be in the very early stages, all the indicators pointed in that direction.

Until recently, the image of Alzheimer’s was the clearly demented person with the sometimes vacant stare, unable to follow a conversation or remember a promise to meet a friend for lunch.

Ms. Popkin is nothing like that. To a casual observer, the articulate and groomed Ms. Popkin seems perfectly fine. She is in the vanguard of a new generation of Alzheimer’s patients, given a diagnosis after tests found signs of the disease years before actual dementia sets in.

But the new diagnostic tests are leading to a moral dilemma. Since there is no treatment for Alzheimer’s, is it a good thing to tell people, years earlier, that they have this progressive degenerative brain disease or have a good chance of getting it?

“I am grappling with that issue,” Dr. Rafii said. “I give them the diagnosis — we are getting pretty good at diagnosis now. But it’s challenging because what do we do then?”

It is a quandary that is emblematic of major changes in the practice of medicine, affecting not just Alzheimer’s patients. Modern medicine has produced new diagnostic tools, from scanners to genetic tests, that can find diseases or predict disease risk decades before people would notice any symptoms.

At the same time, many of those diseases have no effective treatments. Does it help to know you are likely to get a disease if there is nothing you can do?

“This is the price we pay” for the new knowledge, said Dr. Jonathan D. Moreno, a professor of medical ethics and the history and sociology of science at the University of Pennsylvania.

“I think we are going to go through a really tough time,” he added. “We have so much information now, and we have to try to learn as a culture what information we do not want to have.”

Some doctors, like Dr. John C. Morris of Washington University in St. Louis, say they will not offer the new diagnostic tests for Alzheimer’s — like M.R.I.’s and spinal taps — to patients because it is not yet clear how to interpret them. He uses them in research studies but does not tell subjects the results.

“We don’t know for certain what these results mean,” Dr. Morris said. “If you have amyloid in your brain, we don’t know for certain that you will become demented, and we don’t have anything we can do about it.”

But many people want to know anyway and say they can handle the uncertainty.

That issue is facing investigators in a large federal study of early signs of Alzheimer’s. The researchers, who include Dr. Morris, have been testing and following hundreds of people aged 55 to 90, some with normal memories, some with memory problems and some with dementia. So far, only investigators know the results. Now, the question is, should those who want to learn what their tests show be told?

“We are just confronting this,” said Dr. Richard J. Hodes, director of the National Institute on Aging. “Bioethicists are talking with scientists and the public about what is the right thing to do.”

Risk Levels, but No Scores

Dr. Rafii learned about the new tests and how to use them because he is an investigator in that large federal study. But many who come to the memory disorders clinic at the University of California, San Diego, where Dr. Rafii works, are not part of that study, the Alzheimer’s Disease Neuroimaging Initiative, and simply want to know what is wrong with their brains.

So Dr. Rafii sometimes offers the study’s diagnostic tests: spinal taps and M.R.I.’s to look for shrinkage in important areas of the brain; PET scans to look for the telltale signs of Alzheimer’s in the brain. He calls it “ADNI in the real world,” referring to the study’s acronym. Others, too, offer such tests, although doctors differ in how far they will go.

Dr. Mony J. de Leon of New York University, for example, takes a middle ground. He is studying people at increased risk for Alzheimer’s or other dementias, especially those whose mothers had Alzheimer’s. That sort of family history, he has found, makes the disease more likely.

Many who come to his clinic have no memory problems, but are worried. So Dr. de Leon enrolls them in a study and regularly subjects them to an array of tests — ones that probe their memory, and ones like spinal taps and brain scans that look for signs of Alzheimer’s. But he only provides people with a sort of general assessment, telling them they are at increased risk, decreased risk or somewhere in the middle.

“We do not reveal their scores,” Dr. de Leon said.

Some are satisfied with that.

Enzo Simone, for example, learned that, at age 43, his tests results do not indicate an increased risk. He was glad to know, but is not convinced he has escaped what he sees as a family fate. His mother, grandmother and great-grandmother had Alzheimer’s. They got the disease in their 60s. Mr. Simone, who lives in Amawalk, N.Y., reasoned that he had 20 years before it was likely to strike. And he intends to continue being tested as part of Dr. de Leon’s study.

And for those who demand more details than just a “yes,” “no” or “maybe,” Dr. de Leon refuses.

“We say, ‘It is a statistical exercise, it is a proof of concept, it is a baby test,’ ” Dr. de Leon said. “Some say: ‘That’s not good enough. I come back to you every year, and if you want me to continue I need more than that.’ ”

But Dr. de Leon said he was constrained by his hospital’s ethics board, which has to approve his studies. It is extremely difficult, he says, to convince the board that giving out uncertain information about risk can help people, given that there is no effective treatment. And so, he says, he tells patients, “You are here to do an experiment.”

Others, like Dr. Lawrence Honig of Columbia University, say they sometimes see patients with no symptoms of memory loss who are nonetheless worried about their risk. Some of them have already gotten one of the early diagnostic tests, like a spinal tap or brain scan, from a neurologist in private practice, and have been told they were on their way to developing Alzheimer’s. They come to Dr. Honig, hoping he will say it is not true.

That situation, Dr. Honig says, “has become more and more common over the last few years.” He says that when test results are consistent with Alzheimer’s, he is honest about it, telling patients that the results are “suggestive of Alzheimer’s” but adding that all he can say for sure is “at some point in the future, you might be faced with that condition.”

He agonizes, though, over telling people news like that.

“I think it’s pretty terrible,” Dr. Honig said. “It is psychologically invasive.”

But for neurologists like Dr. de Leon, the future is fast approaching, as patients increasingly demand to know.

“The floodgate is about to open,” Dr. de Leon said.

Information’s Burden

At Boston University, Dr. Robert Green faced an ethical dilemma. He wanted to test people for a gene, APOE, that has three variants. People with two copies of one of the variants, APO e4, have a 12- to 15-fold increased risk of Alzheimer’s disease. People with even one copy of the gene variant have about a threefold increased risk.

Five different published consensus statements by ethicists and neurologists had considered the question of whether people should be told the results of APOE tests. And every one of those committee said the answer is no, do not tell.

Dr. Green wondered if that answer was right.

“It seemed rather strange to be in a position where family members are coming to you and saying, ‘I really understand APOE genotyping and the idea of a risk gene, and I want to know my genotype,’ and then to say to them, ‘I could tell you that, but I’m not going to.’ ” After all, he said, “Part of what we do in medicine is to inform.”

He knew what it meant to tell people they were at high risk.

“Alzheimer’s is a fearsome disease,” he said. “You can’t get much more fearsome than Alzheimer’s.” And yet, he said, “People still wanted to know.”

He decided to do a study to see what would happen if he told.

The first surprise was how many people wanted to know. To be in the study, a person had to have a first-degree relative who had had Alzheimer’s, making it more likely that they would have an APO e4 variant. Dr. Green thought maybe a small percentage of the people he approached would want to have the genetic test. Instead, nearly a quarter did.

“Frankly, we were terrified in early days of this study,” Dr. Green said. “We did not want to harm anyone. We were very, very thoughtful and intense. We sat with people beforehand and asked if they were really sure they wanted to do this.”

But his subjects were fine with the testing. After they gave the subjects their test results, researchers looked for psychological effects, observing participants in conversations and administering standardized questions designed to detect anxiety or depression or suicidal thoughts. They found nothing.

The main difference between those who found out they had APO e4 and those who found out they did not have that gene variant is that the APO e4 subjects were more likely to buy long term care insurance, were more likely to start exercising and were more likely to start taking vitamins and nutritional supplements, even though these practices and products have never been shown to protect against Alzheimer’s.

For many, though, the news was good — they did not have APO e4.

That is what happened with Alan Whitney, a 66-year-old radio astronomer at the Massachusetts Institute of Technology, whose mother and mother’s father both had Alzheimer’s. He wanted the test, he said, knowing what it meant to have APO e4.

“That was a gamble I took,” he said.

And he was lucky. If he had had an APO e4 gene, he said, he might have taken early retirement and traveled.

“Now I feel I have some time.” Dr. Whitney said.

Robert Stuart-Vail, an 83-year-old retired columnist for his local newspaper in Lincoln, Mass., was not so lucky. He found out he has one copy of the APO e4 gene. His father had Alzheimer’s and so did his wife, who died from it, so he knows full well what the disease entails

“I wanted to know,” Mr. Stuart-Vail said. “I wanted to be able to tell my children.”

When he told them, though, they did not say much, Mr. Stuart-Vail said.

“I don’t think it meant that much to them. Alzheimer’s — that’s something that happens to old people.” Mr. Stuart-Vail’s children are middle-aged.

As for Mr. Stuart-Vail, he believes staying active will help stave off the disease if it is in his future. And he has come to terms with his genetics.

“You play the cards you are dealt,” he said.

The Days Get Harder

In San Diego, Marjie Popkin said her memory problems had gotten steadily worse in the year since she first saw Dr. Rafii.

For example, she says, she has two cats. “I have to remember when I walk out that door that they can’t come with me.”

She used to read “all the time.” Now, she says, reading is difficult. She depends on a friend, Taffy Jones, who took her to her appointment with Dr. Rafii, and who visits often and calls her every day.

But that is hard for Ms. Jones.

In many respects, Ms. Jones said, Ms. Popkin is perfectly normal. She remembers to feed her cats, she changes their litter box every day, she showers.

“Other things she is not able to deal with at all,” Ms. Jones said. Getting dressed has become a problem, and Ms. Jones has to call Ms. Popkin every morning and every night to remind her to take her pills. Ms. Popkin can no longer drive and relies on Ms. Jones to help with routine things, like getting groceries. Helping Ms. Popkin has become a time-consuming chore.

Ms. Popkin is all too aware of the situation she is in, dependent on the kindness of neighbors and Ms Jones.

“I am trying to adjust, but it’s not easy,” Ms. Popkin said in a telephone conversation. “I am pretty pragmatic. I know what the score is.”

Sometimes she sits in her apartment and just cries and cries. She has no family, and Ms. Jones is her only remaining friend; the others have drifted away.

The diagnosis of early-stage Alzheimer’s disease was a shock, Ms. Popkin said, like “a punch in the stomach.”

“This brain’s been with me since I was born — how can it change like that? Sometimes I have to think, ‘Is this really happening to me?’ ”

Her only consolation, she says, is that her father, her last remaining family member other than a cousin in North Carolina, died a few years ago, before she got the diagnosis. “He would have been devastated.”

And Ms. Popkin — is she glad now that she found out what is wrong?

“I wish I didn’t know,” she said.
 
Tests Detect Alzheimer’s Risks, but Should Patients Be Told?
http://www.nytimes.com/2010/12/18/health/18moral.html

December 17, 2010
By GINA KOLATA

Marjie Popkin thought she had chemo brain, that fuzzy-headed forgetful state that she figured was a result of her treatment for ovarian cancer. She was not thinking clearly — having trouble with numbers, forgetting things she had just heard.

One doctor after another dismissed her complaints. Until recently, since she was, at age 62, functioning well and having no trouble taking care of herself, that might have been the end of her quest for an explanation.

Last year, though, Ms. Popkin, still troubled by what was happening to her mind, went to Dr. Michael Rafii, a neurologist at the University of California, San Diego, who not only gave her a thorough neurological examination but administered new tests, like an M.R.I. that assesses the volume of key brain areas and a spinal tap.

Then he told her there was something wrong. And it was not chemo brain. It most likely was Alzheimer’s disease. Although she seemed to be in the very early stages, all the indicators pointed in that direction.

Until recently, the image of Alzheimer’s was the clearly demented person with the sometimes vacant stare, unable to follow a conversation or remember a promise to meet a friend for lunch.

Ms. Popkin is nothing like that. To a casual observer, the articulate and groomed Ms. Popkin seems perfectly fine. She is in the vanguard of a new generation of Alzheimer’s patients, given a diagnosis after tests found signs of the disease years before actual dementia sets in.

But the new diagnostic tests are leading to a moral dilemma. Since there is no treatment for Alzheimer’s, is it a good thing to tell people, years earlier, that they have this progressive degenerative brain disease or have a good chance of getting it?

“I am grappling with that issue,” Dr. Rafii said. “I give them the diagnosis — we are getting pretty good at diagnosis now. But it’s challenging because what do we do then?”

It is a quandary that is emblematic of major changes in the practice of medicine, affecting not just Alzheimer’s patients. Modern medicine has produced new diagnostic tools, from scanners to genetic tests, that can find diseases or predict disease risk decades before people would notice any symptoms.

At the same time, many of those diseases have no effective treatments. Does it help to know you are likely to get a disease if there is nothing you can do?

“This is the price we pay” for the new knowledge, said Dr. Jonathan D. Moreno, a professor of medical ethics and the history and sociology of science at the University of Pennsylvania.

“I think we are going to go through a really tough time,” he added. “We have so much information now, and we have to try to learn as a culture what information we do not want to have.”

Some doctors, like Dr. John C. Morris of Washington University in St. Louis, say they will not offer the new diagnostic tests for Alzheimer’s — like M.R.I.’s and spinal taps — to patients because it is not yet clear how to interpret them. He uses them in research studies but does not tell subjects the results.

“We don’t know for certain what these results mean,” Dr. Morris said. “If you have amyloid in your brain, we don’t know for certain that you will become demented, and we don’t have anything we can do about it.”

But many people want to know anyway and say they can handle the uncertainty.

That issue is facing investigators in a large federal study of early signs of Alzheimer’s. The researchers, who include Dr. Morris, have been testing and following hundreds of people aged 55 to 90, some with normal memories, some with memory problems and some with dementia. So far, only investigators know the results. Now, the question is, should those who want to learn what their tests show be told?

“We are just confronting this,” said Dr. Richard J. Hodes, director of the National Institute on Aging. “Bioethicists are talking with scientists and the public about what is the right thing to do.”

Risk Levels, but No Scores

Dr. Rafii learned about the new tests and how to use them because he is an investigator in that large federal study. But many who come to the memory disorders clinic at the University of California, San Diego, where Dr. Rafii works, are not part of that study, the Alzheimer’s Disease Neuroimaging Initiative, and simply want to know what is wrong with their brains.

So Dr. Rafii sometimes offers the study’s diagnostic tests: spinal taps and M.R.I.’s to look for shrinkage in important areas of the brain; PET scans to look for the telltale signs of Alzheimer’s in the brain. He calls it “ADNI in the real world,” referring to the study’s acronym. Others, too, offer such tests, although doctors differ in how far they will go.

Dr. Mony J. de Leon of New York University, for example, takes a middle ground. He is studying people at increased risk for Alzheimer’s or other dementias, especially those whose mothers had Alzheimer’s. That sort of family history, he has found, makes the disease more likely.

Many who come to his clinic have no memory problems, but are worried. So Dr. de Leon enrolls them in a study and regularly subjects them to an array of tests — ones that probe their memory, and ones like spinal taps and brain scans that look for signs of Alzheimer’s. But he only provides people with a sort of general assessment, telling them they are at increased risk, decreased risk or somewhere in the middle.

“We do not reveal their scores,” Dr. de Leon said.

Some are satisfied with that.

Enzo Simone, for example, learned that, at age 43, his tests results do not indicate an increased risk. He was glad to know, but is not convinced he has escaped what he sees as a family fate. His mother, grandmother and great-grandmother had Alzheimer’s. They got the disease in their 60s. Mr. Simone, who lives in Amawalk, N.Y., reasoned that he had 20 years before it was likely to strike. And he intends to continue being tested as part of Dr. de Leon’s study.

And for those who demand more details than just a “yes,” “no” or “maybe,” Dr. de Leon refuses.

“We say, ‘It is a statistical exercise, it is a proof of concept, it is a baby test,’ ” Dr. de Leon said. “Some say: ‘That’s not good enough. I come back to you every year, and if you want me to continue I need more than that.’ ”

But Dr. de Leon said he was constrained by his hospital’s ethics board, which has to approve his studies. It is extremely difficult, he says, to convince the board that giving out uncertain information about risk can help people, given that there is no effective treatment. And so, he says, he tells patients, “You are here to do an experiment.”

Others, like Dr. Lawrence Honig of Columbia University, say they sometimes see patients with no symptoms of memory loss who are nonetheless worried about their risk. Some of them have already gotten one of the early diagnostic tests, like a spinal tap or brain scan, from a neurologist in private practice, and have been told they were on their way to developing Alzheimer’s. They come to Dr. Honig, hoping he will say it is not true.

That situation, Dr. Honig says, “has become more and more common over the last few years.” He says that when test results are consistent with Alzheimer’s, he is honest about it, telling patients that the results are “suggestive of Alzheimer’s” but adding that all he can say for sure is “at some point in the future, you might be faced with that condition.”

He agonizes, though, over telling people news like that.

“I think it’s pretty terrible,” Dr. Honig said. “It is psychologically invasive.”

But for neurologists like Dr. de Leon, the future is fast approaching, as patients increasingly demand to know.

“The floodgate is about to open,” Dr. de Leon said.

Information’s Burden

At Boston University, Dr. Robert Green faced an ethical dilemma. He wanted to test people for a gene, APOE, that has three variants. People with two copies of one of the variants, APO e4, have a 12- to 15-fold increased risk of Alzheimer’s disease. People with even one copy of the gene variant have about a threefold increased risk.

Five different published consensus statements by ethicists and neurologists had considered the question of whether people should be told the results of APOE tests. And every one of those committee said the answer is no, do not tell.

Dr. Green wondered if that answer was right.

“It seemed rather strange to be in a position where family members are coming to you and saying, ‘I really understand APOE genotyping and the idea of a risk gene, and I want to know my genotype,’ and then to say to them, ‘I could tell you that, but I’m not going to.’ ” After all, he said, “Part of what we do in medicine is to inform.”

He knew what it meant to tell people they were at high risk.

“Alzheimer’s is a fearsome disease,” he said. “You can’t get much more fearsome than Alzheimer’s.” And yet, he said, “People still wanted to know.”

He decided to do a study to see what would happen if he told.

The first surprise was how many people wanted to know. To be in the study, a person had to have a first-degree relative who had had Alzheimer’s, making it more likely that they would have an APO e4 variant. Dr. Green thought maybe a small percentage of the people he approached would want to have the genetic test. Instead, nearly a quarter did.

“Frankly, we were terrified in early days of this study,” Dr. Green said. “We did not want to harm anyone. We were very, very thoughtful and intense. We sat with people beforehand and asked if they were really sure they wanted to do this.”

But his subjects were fine with the testing. After they gave the subjects their test results, researchers looked for psychological effects, observing participants in conversations and administering standardized questions designed to detect anxiety or depression or suicidal thoughts. They found nothing.

The main difference between those who found out they had APO e4 and those who found out they did not have that gene variant is that the APO e4 subjects were more likely to buy long term care insurance, were more likely to start exercising and were more likely to start taking vitamins and nutritional supplements, even though these practices and products have never been shown to protect against Alzheimer’s.

For many, though, the news was good — they did not have APO e4.

That is what happened with Alan Whitney, a 66-year-old radio astronomer at the Massachusetts Institute of Technology, whose mother and mother’s father both had Alzheimer’s. He wanted the test, he said, knowing what it meant to have APO e4.

“That was a gamble I took,” he said.

And he was lucky. If he had had an APO e4 gene, he said, he might have taken early retirement and traveled.

“Now I feel I have some time.” Dr. Whitney said.

Robert Stuart-Vail, an 83-year-old retired columnist for his local newspaper in Lincoln, Mass., was not so lucky. He found out he has one copy of the APO e4 gene. His father had Alzheimer’s and so did his wife, who died from it, so he knows full well what the disease entails

“I wanted to know,” Mr. Stuart-Vail said. “I wanted to be able to tell my children.”

When he told them, though, they did not say much, Mr. Stuart-Vail said.

“I don’t think it meant that much to them. Alzheimer’s — that’s something that happens to old people.” Mr. Stuart-Vail’s children are middle-aged.

As for Mr. Stuart-Vail, he believes staying active will help stave off the disease if it is in his future. And he has come to terms with his genetics.

“You play the cards you are dealt,” he said.

The Days Get Harder

In San Diego, Marjie Popkin said her memory problems had gotten steadily worse in the year since she first saw Dr. Rafii.

For example, she says, she has two cats. “I have to remember when I walk out that door that they can’t come with me.”

She used to read “all the time.” Now, she says, reading is difficult. She depends on a friend, Taffy Jones, who took her to her appointment with Dr. Rafii, and who visits often and calls her every day.

But that is hard for Ms. Jones.

In many respects, Ms. Jones said, Ms. Popkin is perfectly normal. She remembers to feed her cats, she changes their litter box every day, she showers.

“Other things she is not able to deal with at all,” Ms. Jones said. Getting dressed has become a problem, and Ms. Jones has to call Ms. Popkin every morning and every night to remind her to take her pills. Ms. Popkin can no longer drive and relies on Ms. Jones to help with routine things, like getting groceries. Helping Ms. Popkin has become a time-consuming chore.

Ms. Popkin is all too aware of the situation she is in, dependent on the kindness of neighbors and Ms Jones.

“I am trying to adjust, but it’s not easy,” Ms. Popkin said in a telephone conversation. “I am pretty pragmatic. I know what the score is.”

Sometimes she sits in her apartment and just cries and cries. She has no family, and Ms. Jones is her only remaining friend; the others have drifted away.

The diagnosis of early-stage Alzheimer’s disease was a shock, Ms. Popkin said, like “a punch in the stomach.”

“This brain’s been with me since I was born — how can it change like that? Sometimes I have to think, ‘Is this really happening to me?’ ”

Her only consolation, she says, is that her father, her last remaining family member other than a cousin in North Carolina, died a few years ago, before she got the diagnosis. “He would have been devastated.”

And Ms. Popkin — is she glad now that she found out what is wrong?

“I wish I didn’t know,” she said.
 
Muller M, Schupf N, Manly JJ, Mayeux R, Luchsinger JA. Sex hormone binding globulin and incident Alzheimer's disease in elderly men and women. Neurobiol Aging 2010;31(10):1758-65. Sex hormone binding globulin and incident Alzheimer’s disease in elderly men and women

It has been suggested that low levels of estradiol and testosterone increase dementia risk. However, results of the existing observational studies examining associations of endogenous sex hormones with cognition and dementia are conflicting. A possible explanation for these inconsistent findings could be the involvement of sex hormone-binding globulin (SHBG) in regulating sex hormone levels. In the present study, we examined whether SHBG levels were associated with development of AD and overall dementia in a cohort of elderly men and women free of dementia at baseline. We observed that in both men and women higher levels of SHBG were associated with an increased risk for AD and overall dementia. These results were independent of vascular risk factors and bioactive hormone levels. Whether SHBG is causally related to dementia or whether it is a surrogate marker for rate of biological aging and increased risk or for preclinical stage of dementia has to be elucidated.
 
Prior to the industrial revolution, human exposure to aluminum .... arguably a necessary component of these amyloid plaques, was almost zero. This element has been released by man, and while a direct cause and effect relationship hasn't been established in all cases of Alzheimers, the fact remains; this element is only available to people, because we've allowed it to be.

What lead was to Rome I, aluminum is to Rome II.
 
This was ruled out at least 25 years ago.
Current theories include:
1. Impaired glucose cerebral glucose metabolism. Studies indicate that dietary lactose supplementation is helpful.
2. Acetylcholinesterase inhibitors are the main line of defense.
3. Glutamate inhibitors and minoclycline postpone hypocampal neuron apotisis.
4 Genetic variance is the most probable cause; APO4E gene if that helps

Prior to the industrial revolution, human exposure to aluminum .... arguably a necessary component of these amyloid plaques, was almost zero. This element has been released by man, and while a direct cause and effect relationship hasn't been established in all cases of Alzheimers, the fact remains; this element is only available to people, because we've allowed it to be.

What lead was to Rome I, aluminum is to Rome II.
 
President Obama signed the National Alzheimer's Project Act (NAPA) into law. The aim of the new law is to create a coordinated national strategy that deals with Alzheimer's, a brain-wasting condition projected to leap from 5.3 million cases this year into the double digits by midcentury. Even though the new law doesn't in itself deliver money for research to find a cure or support services for patients and caregivers grappling with the disease, it will help establish an interagency council that will work with the secretary of Health and Human Services to give a full assessment of what needs to be accomplished to stem the disease. Alzheimer's economic burden is a major concern. Under current conditions, total care costs could escalate from $172 billion today to more than $1 trillion by 2050. http://www.kintera.org/atf/cf/{B96E2E84-AF7D-4656-9C86-285306F00E19}/HR4689.pdf
 

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Alzheimer's blood test 'most accurate' so far
Alzheimer's blood test 'most accurate' so far : Nature News

The blood of patients with the brain disease contains antibodies not found in healthy people.

Published online 6 January 2011
Ewen Callaway

A new blood test diagnoses Alzheimer's disease by sensing molecules produced by the immune systems of people with the neurodegenerative condition.

So far, the test has been applied to just a small number of blood samples, but if proven on a larger scale, the assay could help diagnose Alzheimer's disease in combination with other tests, says Thomas Kodadek, a professor of chemistry at the Scripps Research Institute in Jupiter, Florida. It could also be used to identify patients for trials of experimental Alzheimer's drugs, he adds. His team published its results online today in Cell1.

Currently, the only way to conclusively distinguish Alzheimer's from other dementias by examining the gnarled plaques and tangles of protein found in the brains of those with the condition. This can only be done after death. A furious search is under way for earlier, less-invasive tests using brain scans, blood draws and spinal taps, for instance.

Globally, over 35 million people suffer from Alzheimer's. There are no effective treatments for the disease or proven means of preventing it.

Most trawls for blood biomarkers typically whittle down a list of potential molecules to a few that differ between people with a condition and healthy people. For instance, Tony Wyss-Coray's team at Stanford University in California screened 120 proteins involved in cell communication and found 18 of the proteins present at higher levels in the blood of people with Alzheimer's disease than others2.

However, such 'candidate' screens rely on assumptions about which molecules are likely to be affected by a disease. They also rely on sensing vanishingly small levels of proteins and other molecules.

Slide screen

Antibodies — immune molecules in blood that stick to specific foreign and disease proteins — offer a solution, says Kodadek. If specific to a disease, they are likely to be found in high levels in those with the condition, yet be absent in healthy people.

Typically, a scientist would fish out such antibodies using the disease proteins they attack. However, Kodadek's team reasoned that antibodies should also recognize other kinds of molecules. They created glass slides coated with thousands of differently shaped peptoid molecules — chemical cousins of peptides that are likely to be recognized by antibodies.

As a proof of principle, Kodadek's team searched for antibodies produced by mice that have a multiple sclerosis-like condition caused by their antibodies attacking the fatty sheaths surrounding nerves. Among the 4,800 peptoids on the slide, several latched onto antibodies in the blood of mice with the disease, but this did not happen for controls. "It was a night-and-day difference, it wasn't a subtle thing," he says.

Next, the researchers tested the peptoid slides on blood from six likely Alzheimer's patients, six similarly aged healthy people, and six patients with a different neurodegenerative condition, Parkinson's disease.

They identified three peptoids that recognized antibodies from people suspected to have Alzheimer's. Tested against 16 different people with the condition, each peptoid proved more than 93% accurate at diagnosing Alzheimer's, meaning they missed only one Alzheimer's case out of 16.

Antibody issue

In unpublished work, Kodadek says his team has applied the test to about 300 people, correctly diagnosing 98% of the people thought to have Alzheimer's. Meanwhile, the test proved 95% accurate at distinguishing healthy people from those suspected to have Alzheimer's, yet Kodadek doubts all 5% are true false positives. "I'm really pretty sure what we're seeing is pre-symptomatic Alzheimer's," he says.

Current tests for Alzheimer's relying on brain imaging and spinal tap accurately diagnose about 90% of patients, says Kodadek. "One could imagine our test being used a cheap front line screen, and at least if you test positive there, you could go for these more expensive things that couldn't be used as a general screen."

Kaj Blennow, an expert on Alzheimer's biomarkers at Sahlgrenska University Hospital in Mölndal, Sweden, calls the findings "very promising" but says they need to be replicated in a larger group of patients, including those at early stages of Alzheimer's and with other forms of dementia.

Wyss-Coray says it is still an open question as to whether or not people with Alzheimer's produce antibodies that are specific to their condition. However, the small number of peptoids unique to those with the disease could point to a very specific immune response against an unknown disease molecule. "If true, that would most certainly change the current view of this disease."

Kodadek's team is hoping to find the molecule or molecules recognized by the Alzheimer's antibodies. They also plan to apply the peptoid screen to discovering antibodies against various cancers.

A company he is involved with, Opko Health based in Miami, Florida, plans to work with a large pharmaceutical firm to identify people suitable for its clinical trials. "If we're ever going to get an Alzheimer's drug, we need a much better early diagnostic. Otherwise these trials are doomed to failure," Kodadek adds.

References

1. Reddy, M. M. et al. Cell 144, 132-142 (2011).

2. Ray, S. et al. Nature Medicine 13, 1359-1362 (2007).
 
My own understanding of it is that Alzheimer's and most cancers are associated with metabolic syndrome, obesity, and diabetes. So much so, that some researchers refer to Alzheimer's as "type 3 diabetes".
 
Re. impaired cerebral glucose metabolism and ( fatty acid) ketone bodies;
Shifting the brain into fatty acid metabolism appears helpful.

Does Exercise Really Make Us Thinner? -- New York Magazine

The job of determining how fuels (glucose and fatty acids) will be used, whether we will store them as fat or burn them for energy, is carried out primarily by the hormone insulin in concert with an enzyme known technically as lipoprotein lipase—LPL, for short. (Sex hormones also interact with LPL, which is why men and women fatten differently.)

In the eighties, biochemists and physiologists worked out how LPL responds to exercise. They found that during a workout, LPL activity increases in muscle tissue, and so our muscle cells suck up fatty acids to use for fuel. Then, when we’re done exercising, LPL activity in the muscle tissue tapers off and LPL activity in our fat tissue spikes, pulling calories into fat cells. This works to return to the fat cells any fat they might have had to surrender—homeostasis, in other words. The more rigorous the exercise, and the more fat lost from our fat tissue, the greater the subsequent increase in LPL activity in the fat cells. Thus, post-workout, we get hungry: Our fat tissue is devoting itself to restoring calories as fat, depriving other tissues and organs of the fuel they need and triggering a compensatory impulse to eat. The feeling of hunger is the brain’s way of trying to satisfy the demands of the body. Just as sweating makes us thirsty, burning off calories makes us hungry.




Read more from the MESO-Rx Steroid Forum at: https://thinksteroids.com/community/threads/134300969
 
Re: OnLine First

The last decade has seen a surge in research in biomarkers for Alzheimer disease (AD) and other dementia disorders. With predictions of 1 in 4 persons ultimately developing the disease, disorders causing dementia have become one of the major health concerns in aging societies. Impending costs to society and individuals, as well as the enormous and increasing market potential to industry, make this an extremely important field in which the stakes, pressure, and expectations are high to develop better means to establish presence of disease, monitor progression, and make a diagnosis. In that arena, it is of the utmost importance that biomarkers are evaluated in a valid and rigorous way. Two studies in this issue of JAMA report on possible biomarkers for AD and cognitive decline. Both suggest a promising perspective that biomarkers can be developed and found to enable more accurate and earlier diagnosis of neurodegenerative diseases. At the same time, both illustrate that there is room for improvement when it comes to critical aspects of study design and analysis in biomarker evaluation. [Breteler MMB. Mapping Out Biomarkers for Alzheimer Disease. JAMA: The Journal of the American Medical Association 2011;305(3):304-5. Mapping Out Biomarkers for Alzheimer Disease, January 19, 2011, Breteler 305 (3): 304 — JAMA ]


Yaffe K, Weston A, Graff-Radford NR, et al. Association of Plasma Beta-Amyloid Level and Cognitive Reserve With Subsequent Cognitive Decline. JAMA: The Journal of the American Medical Association 2011;305(3):261-6. Association of Plasma ?-Amyloid Level and Cognitive Reserve With Subsequent Cognitive Decline, January 19, 2011, Yaffe et al. 305 (3): 261 — JAMA

Context Lower plasma ?-amyloid 42 and 42/40 levels have been associated with incident dementia, but results are conflicting and few have investigated cognitive decline among elders without dementia.

Objective To determine if plasma ?-amyloid is associated with cognitive decline and if this association is modified by measures of cognitive reserve.

Design, Setting, and Participants We studied 997 black and white community-dwelling older adults from Memphis, Tennessee, and Pittsburgh, Pennsylvania, who were enrolled in the Health ABC Study, a prospective observational study begun in 1997-1998 with 10-year follow-up in 2006-2007. Participant mean age was 74.0 (SD, 3.0) years; 55.2% (n = 550) were female; and 54.0% (n = 538) were black.

Main Outcome Measures Association of near-baseline plasma ?-amyloid levels (42 and 42/40 measured in 2010) and repeatedly measured Modified Mini-Mental State Examination (3MS) results.

Results Low ?-amyloid 42/40 level was associated with greater 9-year 3MS cognitive decline (lowest ?-amyloid tertile: mean change in 3MS score, ?6.59 [95% confidence interval [CI], ?5.21 to ?7.67] points; middle tertile: ?6.16 [95% CI, ?4.92 to ?7.32] points; and highest tertile: ?3.60 [95% CI, ?2.27 to ?4.73] points; P < .001). Results were similar after multivariate adjustment for age, race, education, diabetes, smoking, and apolipoprotein E [APOE ] e4 status and after excluding the 72 participants with incident dementia. Measures of cognitive reserve modified this association whereby among those with high reserve (at least a high school diploma, higher than sixth-grade literacy, or no APOE e4 allele), ?-amyloid 42/40 was less associated with multivariate adjusted 9-year decline. For example, among participants with less than a high school diploma, the 3MS score decline was ?8.94 (95% CI, ?6.94 to ?10.94) for the lowest tertile compared with ?4.45 (95% CI, ?2.31 to ?6.59) for the highest tertile, but for those with at least a high school diploma, 3MS score decline was ?4.60 (95% CI,?3.07 to ?6.13) for the lowest tertile and ?2.88 (95% CI,?1.41 to ?4.35) for the highest tertile (P = .004 for interaction). Interactions were also observed for literacy (P = .005) and for APOE e4 allele (P = .02).

Conclusion Lower plasma ?-amyloid 42/40 is associated with greater cognitive decline among elderly persons without dementia over 9 years, and this association is stronger among those with low measures of cognitive reserve.


Clark CM, Schneider JA, Bedell BJ, et al. Use of Florbetapir-PET for Imaging Beta-Amyloid Pathology. JAMA: The Journal of the American Medical Association 2011;305(3):275-83. Sign In — JAMA

Context The ability to identify and quantify brain ?-amyloid could increase the accuracy of a clinical diagnosis of Alzheimer disease.

Objective To determine if florbetapir F 18 positron emission tomographic (PET) imaging performed during life accurately predicts the presence of ?-amyloid in the brain at autopsy.

Design, Setting, and Participants Prospective clinical evaluation conducted February 2009 through March 2010 of florbetapir-PET imaging performed on 35 patients from hospice, long-term care, and community health care facilities near the end of their lives (6 patients to establish the protocol and 29 to validate) compared with immunohistochemistry and silver stain measures of brain ?-amyloid after their death used as the reference standard. PET images were also obtained in 74 young individuals (18-50 years) presumed free of brain amyloid to better understand the frequency of a false-positive interpretation of a florbetapir-PET image.

Main Outcome Measures Correlation of florbetapir-PET image interpretation (based on the median of 3 nuclear medicine physicians' ratings) and semiautomated quantification of cortical retention with postmortem ?-amyloid burden, neuritic amyloid plaque density, and neuropathological diagnosis of Alzheimer disease in the first 35 participants autopsied (out of 152 individuals enrolled in the PET pathological correlation study).

Results Florbetapir-PET imaging was performed a mean of 99 days (range, 1-377 days) before death for the 29 individuals in the primary analysis cohort. Fifteen of the 29 individuals (51.7%) met pathological criteria for Alzheimer disease. Both visual interpretation of the florbetapir-PET images and mean quantitative estimates of cortical uptake were correlated with presence and quantity of ?-amyloid pathology at autopsy as measured by immunohistochemistry (Bonferroni ?, 0.78 [95% confidence interval, 0.58-0.89]; P <.001]) and silver stain neuritic plaque score (Bonferroni ?, 0.71 [95% confidence interval, 0.47-0.86]; P <.001). Florbetapir-PET images and postmortem results rated as positive or negative for ?-amyloid agreed in 96% of the 29 individuals in the primary analysis cohort. The florbetapir-PET image was rated as amyloid negative in the 74 younger individuals in the nonautopsy cohort.

Conclusions Florbetapir-PET imaging was correlated with the presence and density of ?-amyloid. These data provide evidence that a molecular imaging procedure can identify ?-amyloid pathology in the brains of individuals during life. Additional studies are required to understand the appropriate use of florbetapir-PET imaging in the clinical diagnosis of Alzheimer disease and for the prediction of progression to dementia.
 
Beta amyloid, aluminum, melatonin, alzheimers

I stated that Al had been excluded as having any relationship to AD.
I was wrong.
Study describes the etiology of neuron cell death due to BA and Al.
Furthermore finds that the antioxidant properties of melatonin reduce this effect.
 
Re: Beta amyloid, aluminum, melatonin, alzheimers

Too many acronyms for mainstream public.. Please elaborate....:)

I stated that Al had been excluded as having any relationship to AD.
I was wrong.
Study describes the etiology of neuron cell death due to BA and Al.
Furthermore finds that the antioxidant properties of melatonin reduce this effect.
 
Nicotine is effective as a treatment of Alzheimers

Abstract
1. Recent studies indicate that neuronal loss in Alzheimer's disease (AD) is accompanied by the deposition of beta-amyloid protein (A beta) in senile plaques. Nicotine as a major component of cigarette smoke has been suggested to have a protective effect for neurons against A beta neurotoxicity. 2. Our present study demonstrates that nicotine protected cultured hippocampal neurons against the A beta-induced apoptosis. Nicotine effectively inhibits apoptosis in hippocampal cultures caused by A beta(25-35) or A beta(1-40) treatment and increase of caspase activity induced by A beta(25-35) or A beta(1-40). 3. Measurements of cellular oxidation and intracellular free Ca(2+) showed that nicotine suppressed A beta-induced accumulation of free radical and increase of intracellular free Ca(2+). 4. Cholinergic antagonist mecamylamine inhibited nicotine-induced protection against A beta-induced caspase-3 activation and ROS accumulation. 5. The data show that the protection of nicotine is partly via nicotinic receptors. Our results suggest that nicotine may be beneficial in retarding the neurodegenerative diseases such as AD.

Nicotine attenuates beta-amyloid peptide-induced n... [Br J Pharmacol. 2004] - PubMed result
 
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