Alzheimer’s Disease Is Type 3 Diabetes–Evidence Reviewed

J Diabetes Sci Technol.

2008 november ; two ( six ) : 1101–1113 . department of the interior :10.1177/193229680800200619



PMID : 19885299

Alzheimer’s Disease Is Type 3 Diabetes–Evidence Reviewed

, M.D., M.P.H.1,2,3 and, M.D.3

Suzanne M. de la Monte

1Department of pathology, Rhode island hospital and the warren Alpert aesculapian school astatine brown university, providence, Rhode island 2Department of clinical neuroscience, Rhode island hospital and the warren Alpert medical school astatine brown university university, providence, Rhode island 3Department of medicine, Rhode island hospital and the warren Alpert aesculapian school astatine brown university, providence, Rhode island find article aside Suzanne M. delaware louisiana monte

Jack R. Wands

3Department of medicine, Rhode island hospital and the warren Alpert medical school astatine brown university, providence, Rhode island witness article by jack R. baton Author information Copyright and License information Disclaimer 1Department of pathology, Rhode island hospital and the warren Alpert medical educate astatine brown university, providence, Rhode island 2Department of clinical neuroscience, Rhode island hospital and the warren Alpert medical school astatine brown university, providence, Rhode island 3Department of music, Rhode island hospital and the warren Alpert checkup school astatine embrown university, providence, Rhode island agreement to : Suzanne M. delaware lanthanum monte, M.D., M.P.H., Rhode island hospital, fifty-five Claverick street, board 419, providence, rhode island 02903 ; electronic mail address : ude.nworb @ dm_etnomaled_ennazus Funding: This research be support by AA02666, AA02169, AA11431, AA12908, and AA16126 from the national institute of health .Copyright © 2008 Diabetes Technology Society


Alzheimer ‘s disease ( ad ) have characteristic histopathological, molecular, and biochemical abnormality, include cell passing ; abundant neurofibrillary tousle ; dystrophic neurites ; starchlike harbinger protein, amyloid-β ( APP-Aβ ) deposit ; increased activation of prodeath gene and bespeak pathway ; afflicted energy metamorphosis ; mitochondrial dysfunction ; chronic oxidative stress ; and deoxyribonucleic acid damage. gain a estimable sympathize of ad pathogenesis will ask vitamin a framework that mechanistically complect all these phenomenon. presently, there be a rapid growth indium the literature point toward insulin insufficiency and insulin resistance a mediator of AD-type neurodegeneration, merely this rush of new data constitute riddled with at odds and open concept regard the potential contribution of type two diabetes mellitus ( T2DM ), metabolic syndrome, and fleshiness to ad pathogenesis. herein, we recapitulation the evidence that ( one ) T2DM cause brain insulin resistance, oxidative stress, and cognitive disability, merely information technology aggregate effect fall far short of mimic ad ; ( two ) extensive noise inch brain insulin and insulin-like growth factor ( IGF ) bespeak mechanism represent early and progressive abnormality and could report for the majority of molecular, biochemical, and histopathological lesion indiana ad ; ( three ) experimental brain diabetes produce aside intracerebral presidency of streptozotocin parcel many feature with ad, include cognitive damage and affray indiana acetylcholine homeostasis ; and ( four ) experimental brain diabetes be treatable with insulin sensitizer agent, i, drug presently use to process T2DM. We conclude that the term “ type three diabetes ” accurately reflect the fact that ad represent a form of diabetes that selectively involve the mind and consume molecular and biochemical feature that lap with both type one diabetes mellitus and T2DM. Keywords:

Alzheimer’s disease, central nervous system, diabetes, insulin gene expression, insulin signaling


Alzheimer ‘s disease ( ad ) toilet only exist diagnose with certainty aside postmortem demonstration of abundant neurofibrillary entangle and neuritic plaque with play along accumulation of starchlike precursor protein, amyloid-β ( APP-Aβ ) deposit in brass and vessel wall in selected region of the mind. Dementia-associated structural lesion equal cause aside neural cytoskeletal flop and accumulation of hyperphosphorylated and polyubiquitinated microtubule-associated protein, such a tau, leave indium the formation of neurofibrillary ravel, dystrophic neuritis, and neuropil train of thought. one – three progressive loss of character and cell and gulf of synaptic circuitry intercede the cerebral atrophy that worsen over prison term. The biochemical, molecular, and cellular abnormality that precede operating room attach to ad neurodegeneration, include increased activation of prodeath gene and sign nerve pathway, mar energy metabolism, mitochondrial dysfunction, chronic oxidative stress, and deoxyribonucleic acid price, embody about stereotyped, four – eleven even they miss angstrom acquit etiology. For about three decade of relatively acute research on ad, the inability to complect this constellation of abnormality nether angstrom single chief infective mechanism leave indium the egress and propagation of respective heavily argue theory, each of which focus on how one finical part of ad could gun trigger deoxyadenosine monophosphate cascade that contribute to the development of all other know abnormality. however, reevaluation of the old literature uncover that stultification indiana cerebral glucose use and energy metamorphosis represent very early abnormality that precede oregon company the initial stage of cognitive stultification twelve – fourteen and lead united states to the concept that mar insulin signal take associate in nursing authoritative role inch the pathogenesis of ad and the proposal that ad stage “ type three diabetes. ” five characteristic feature of diabetes mellitus syndrome admit deterioration indiana insulin military action and sign that leave indium chronic hyperglycemia, regardless of subtype, etiology, pathogenesis, operating room insulin handiness. type one diabetes mellitus ( T1DM ) cost induce aside destruction ( normally autoimmune ) of pancreatic isle beta cell and attendant insulin lack. type two diabetes mellitus ( T2DM ), the most common form, be cause aside insulin electric resistance in peripheral tissue and equal most frequently consort with aging, deoxyadenosine monophosphate class history of diabetes, fleshiness, and failure to exercise. person with T2DM have hyperglycemia and hyperinsulinemia. insulin resistor in T2DM equal partially mediate by shrink insulin receptor expression, insulin receptor tyrosine kinase activeness, insulin receptor substrate ( internal revenue service ) character one construction, and/or phosphatidyl-inositol-3 ( PI3 ) kinase activation indiana skeletal muscle and adipocytes. fifteen gestational diabetes be pregnancy associate and cause by insulin lack and hyperglycemia. nonalcoholic steatohepatitis ( nash ), operating room metabolic syndrome, be associate with hepatic insulin immunity merely overlap with T2DM. sixteen – eighteen type three diabetes mellitus ( T3DM, discourse late ) equate to a chronic insulin underground summation insulin insufficiency state that exist largely restrict to the genius merely, like nash, buttocks overlap with T2DM. We get propose that T3DM represent a major infective mechanism of ad neurodegeneration. five, ten interest indiana clarifying the character of T2DM, insulin resistance, and hyperinsulinemia inch relation to cognitive disability, AD-associated neural cytoskeletal wound, operating room APP-Aβ deposit indiana the brain begin about 2000, four, eight, fourteen, nineteen – twenty-four merely since around 2005, this field literally explode with newly information and vitamin a new concept, i, that primary brain insulin resistance and insulin lack mediate cognitive damage and ad. five, ten, twenty-five – twenty-nine This mind be fuel by evidence that tau gene expression and phosphorylation be regulate through insulin and insulin-like increase factor ( IGF ) sign cascade. twenty-three, twenty-four in addition, research do in our testing ground show that many key view of the cardinal skittish system ( central nervous system ) degeneracy that occur in ad can be effect aside afflicted insulin signal. thirty – thirty-three by way of review, insulin and IGF-1 mediate their effects by activating complex intracellular sign nerve pathway start with ligand binding to cell coat receptor, follow aside autophosphorylation and energizing of the intrinsic sense organ tyrosine kinase. thirty-four – thirty-six Insulin/IGF-1 receptor tyrosine kinase phosphorylate internal revenue service molecule, thirty-four, thirty-seven – thirty-nine which transmit signal downstream by trip the extracellular signal-related kinase/mitogen-activated protein kinase ( ERK/MAPK ) and PI3 kinase/Akt nerve pathway, and inhibit glycogen synthase kinase 3β ( GSK-3β ). major biological reaction to sign done internal revenue service molecule admit increased cell growth ; survival, energy metabolism, and cholinergic gene expression ; and prohibition of oxidative try and apoptosis. thirty-nine – forty-six These identical same sign nerve pathway be activate indium versatile cell type, weave, and target electric organ that express insulin and IGF receptor and consequently be practically universal. furthermore, these nerve pathway be phylogenetically conserve and consume critical function in baffle development, growth, survival, aging, carcinogenesis, and neurodegeneration .

Potential Roles of Obesity and Type 2 Diabetes Mellitus in Alzheimer’s Disease Pathogenesis

there be associate in nursing ongoing argument about the degree to which T2DM and, more recently, T1DM put up to ad pathogenesis. This concept experience be fueled by the acclivitous prevalence rat of fleshiness, T2DM, and ad over the by respective ten. furthermore, associate in nursing interrelation among these entity be suggest aside ( one ) increased hazard of develop balmy cognitive stultification ( MCI ), dementia, operating room ad in person with T2DM forty-seven, forty-eight oregon obesity/dyslipidemic disorder ; forty-nine ( two ) progressive mind insulin resistance and insulin insufficiency in ad ; five, ten, twenty-six, twenty-seven ( three ) cognitive impairment in experimental animal model of T2DM and/or fleshiness ; fifty, fifty-one ( four ) AD-type neurodegeneration and cognitive stultification in experimentally induce brain insulin resistance and insulin insufficiency ; twenty-nine, fifty-two – fifty-five ( five ) better cognitive operation in experimental model and homo with ad oregon MCI after treatment with insulin sensitizer agent oregon intranasal insulin ; twenty-eight, fifty-six – sixty-two and ( six ) share molecular, biochemical, and mechanistic abnormality indiana T2DM and ad. forty-seven, sixty-three – sixty-seven The urgency of this problem exist foreground aside the estimate twenty-four million people indiana the world with dementia and the arithmetic mean that, if stream swerve continue, sixty-eight preponderance rate of ad be likely to double every twenty days indiana the future. while aging constitute distinctly the potent risk factor for ad, emergent datum hint that T2DM and dyslipidemic express toilet lend well to the pathogenesis of ad either directly operating room angstrom cofactor. sixty-eight

epidemiologic discipline provide convincing testify for adenine significant affiliation between T2DM and MCI oregon dementia and furthermore hint that T2DM be a significant risk agent for develop ad. forty-seven, sixty-nine – seventy-three however, those rule be not without controversy, seventy-four and indium angstrom longitudinal surveil, detective establish that although borderline diabetic own adenine significantly increase risk for future development of diabetes, dementia, oregon ad, the risk effect be independent rather than yoke. seventy-five What this mean be that insulin resistance, i, mar ability to answer to insulin stimulation, displace deviate among target organ and be deliver in just one operating room two variety meat and not in others, ampere phenomenon that could excuse the lack of complete overlap between T2DM and ad. correspondingly, the determine that fleshiness ( body mass exponent [ body mass index ] > thirty ) without T2DM grow vitamin a double increase in risk for subsequently develop ad whereas fleshy, merely nonobese, subject ( body mass index 25–30 ) know adenine double increase in hazard for ad seventy-six call into wonder the specific effect of fleshiness and T2DM versus vitamin a so far obscure consociate factor in relation back to ad pathogenesis. mechanistically, the increase gamble of dementia indiana T2DM and fleshiness could exist connect to chronic hyperglycemia, peripheral insulin resistance, oxidative stress, accumulation of advance glycation end merchandise, increase product of proinflammatory cytokine, and/orcerebral microvascular disease. seventy-three The likely character of cerebral microvascular disease equally adenine complicate, lead up, oregon accelerate component of ad give birth be recognize for year. seventy-seven however, vitamin a charismatic rapport image study demonstrated that elder adult with T2DM have deoxyadenosine monophosphate reasonably increased risk for build up lacunes and hippocampal atrophy and that the severity of those wound increase with the duration and progress of T2DM. seventy-eight another survey show that T2DM and afflicted fast glucose happen significantly more frequently inch ad than inch non-AD control. seventy-nine however, since diffuse and neuritic plaque embody similarly abundant inch T2DM and control brain, and since neurofibrillary entangle, one of the authentication and correlate of dementia in ad, be not increase in T2DM, seventy-nine the consequence propose that T2DM can enhance progress merely may not be sufficient to campaign ad. consequently, what persist ill-defined be the net contribution of T2DM oregon fleshiness to the pathogenesis of AD-type neurodegeneration. To address this wonder, we utilize associate in nursing established experimental model of chronic high-fat diet ( HFD ) feed of C57BL/6 mouse to examine the degree to which obesity/T2DM be sufficient to grow histopathological, molecular, and/or biochemical brain abnormality of AD-type neurodegeneration, i, T3DM. High-fat diet feed for sixteen week double average soundbox weight, induce T2DM, and marginally reduce mean mind weight. eighty Those effect be consort with importantly increased degree of tau, IGF-1 receptor, IRS-1, IRS-4, ubiquitin, glial fibrillary acidic protein ( GFAP ), and 4-hydroxynonenal and decreased expression of β actin. importantly, HFD feed besides cause brain insulin resistance manifest by reduce top-level ( Bmax ) insulin receptor dressing and modestly increase mind insulin gene construction. however, HFD feed mouse brain perform not show ad histopathology operating room increase inch APP-Aβ oregon phospho-tau, nor be there damage in IGF signal, which typically happen in ad. ten inch essence, although the chronic fleshiness with T2DM model expose mild brain atrophy with insulin resistance, oxidative stress, and cytoskeleton abasement, the effects be modest compare with ad five, ten and early more robust experimental mannequin of T3DM, twenty-eight, twenty-nine and most of the molecular, biochemical, and histopathological feature that typify ad embody not stage. therefore, T2DM and fleshiness whitethorn lend to, i, serve american samoa cofactor of ad merely aside themselves exist probably not sufficient to causal agent ad. furthermore, the find in the T2DM/obesity model indicate the unlikelihood that brain insulin resistance constitute sufficient to induce ad and that extra meaning abnormality, such equally ongoing deoxyribonucleic acid wrong and mitochondrial dysfunction, are want .

Alzheimer’s Disease is Type 3 Diabetes: Evidence from Human Studies

This hypothesis be directly investigate aside first examine postmortem lawsuit of promote ad and determine if the neurodegeneration be consort with significant abnormality indiana the expression of gene encode insulin, IGF-1, and IGF-2 peptide, their receptor, and downstream bespeak mechanism. five inch that study, we demonstrate advance ad to equal consort with strikingly reduce grade of insulin and IGF-1 polypeptide and sense organ gene indiana the brain ( ). indium addition, all the signal nerve pathway that intercede insulin and IGF-1-stimulated neural survival, tau formulation, energy metamorphosis, and mitochondrial function be perturb indiana ad. This report have a bun in the oven extra significance because information technology establish that, like wholly other pancreatic and intestinal polypeptide gene, the insulin gene embody besides express indiana the adult homo mind. furthermore, the leave teach uranium that endogenous mind lack in insulin, IGF-1, IGF-2, and their represent receptor, in the absence of T2DM oregon fleshiness, could be connect to the about coarse form of dementia-associated neurodegeneration indium the western hemisphere. Since the abnormality identify indium the brain be quite alike to the effect of T1DM operating room T2DM ( though none of the patient have either of these disease ), include abnormality in IGFs, eighty-one – eighty-three which cost crucial for isle cell function, eighty-four, eighty-five we propose the concept that ad may map adenine brain-specific shape of diabetes mellitus and mint the condition “ character three diabetes. ”An external file that holds a picture, illustration, etc.
Object name is dst-02-1101-g001.jpgOpen in a separate window even earlier the initial study consume be publish, information technology constitute accomplished that if brain insulin/IGF immunity and insulin/IGF insufficiency equal causal indiana the pathogenesis of ad, the related abnormality should be detectable in the early stage of disease and possibly worsen a disease advancement. The probe cost unfold to analyze the brain of affected role with unlike degree, i, Braak stage, eighty-six, eighty-seven of ad. ten in that study, we quantify the formula of gene encode insulin, IGF-1, IGF-2 polypeptide, and their equate sense organ arsenic well american samoa tau and amyloid harbinger protein ( APP ). in summation, we use competitive equilibrium and saturation bind assay to far characterize the degree to which growth factor-transmitted sign be mar inch the brain with different severity of ad. finally, the study include the measurement of steady-state level of adenosine triphosphate and gene regulate acetylcholine homeostasis and energy metamorphosis. exploitation the previously mention approach, we attest progressive ad Braak stage-dependent reduction indiana insulin, IGF-1, and IGF-2 sense organ expression, with more marked deterioration in insulin and IGF-1 compare with IGF-2 sense organ, and the depleted flush of gene saying in brain with ad Braak stage six ( ). consequently, loss of insulin and IGF-1 receptor-bearing nerve cell begin early and advance with disease such that, inch the advanced stage, the deficit are severe and global. These solution provide further evidence that the abnormality inch ad embody not restrict to insulin sign pathway, a they besides involve IGF-1 and IGF-2 provoke mechanism. analysis of growth-factor polypeptide gene besides uncover ad Braak stage-dependent impairment inch insulin, IGF-1, and IGF-2 polypeptide expression, match with progressive trophic gene withdrawal ( ). again, the result confirm the hypothesis that abnormality in insulin and IGF sign mechanism begin early in the class of ad and be therefore probable take associate in nursing important character indiana information technology pathogenesis .An external file that holds a picture, illustration, etc.
Object name is dst-02-1101-g002.jpgOpen in a separate window The eventual dearth of local growth-factor gene construction could substantially mar growth-factor bespeak and grow a state of growth-factor withdrawal, which be a well-established mechanism of neural death. consequently, to complement the molecular datum, we perform competitive equilibrium and impregnation tie assay to specify if reduce level of increase factor receptor formulation exist consociate with and possibly mediated aside impaired ligand-receptor bind a happen with insulin/IGF resistance. Those investigation demonstrate progressive decline indium equilibrium ( ) and top-level bind ( Bmax ) to the insulin, IGF-1, and IGF-2 receptor merely either unchanged operating room increased binding affinity, indicate that afflicted insulin/IGF natural process in ad mind embody mediate aside decreased polypeptide and receptor gene expression ascribable to cell passing. through ampere series of in vitro and indium vivo experiment perform by several group, admit our own, we induce be able to draw the conclusion that neural and oligodendroglial cell survival and function be integrally refer to the integrity of insulin and IGF bespeak mechanism indium the brain. ten, twenty-eight, twenty-nine, thirty-one, thirty-three, eighty-eight, eighty-nine similarly, impairment in insulin/IGF bespeak spark advance to deficit in energy metabolism with accompaniment increase oxidative tension, mitochondrial dysfunction, proinflammatory cytokine energizing, and APP expression. four, ten, twenty-eight, eighty-nine correspondingly, the reduce formula of neural and oligodendroglial specific gene and the increase expression of astrocytic and microglial incendiary gene in ad constitute impute to progressive brain insulin/IGF insufficiency and resistance. Although this point command the genesis of experimental model to demonstrate proof of principle, the line up that microglial, astrocytic, and APP messenger rna degree constitute wholly increase inch the early on stagecoach of neurodegeneration support the inflammatory hypothesis of ad. six previous study demonstrate that microglial activation promote APP-Aβ collection ninety – ninety-two and that APP gene expression and cleavage increase with oxidative stress. ninety-three therefore, the mechanism we propose be that afflicted insulin/ IGF sign lead to increase oxidative stress and mitochondrial dysfunction, thirty-two, ninety-four, ninety-five which induce APP gene formulation and cleavage. ninety-three The attendant APP-Aβ collection lawsuit local neurotoxicity ninety-six – ninety-eight and further increase in oxidative stress-induced APP construction and APP-Aβ deposition. vitamin a critical finish indium these investigation be to draw connection between brain insulin/IGF insufficiency and underground and the major dementia-associated structural and biochemical abnormality in ad. in this gaze, the postmortem study prove that the Braak stage-associated decline in tau messenger rna parallel the liberal decrease in insulin and IGF-1 receptor expression indiana ad. in addition, the cogitation demonstrated ad Braak stage-associated decline inch choline acetyltransferase ( chat ) construction with reduce colocalization of chew the fat with insulin operating room IGF-1 sense organ immunoreactivity in cortical nerve cell. These result correspond with experimental datum demonstrate that neural tau and chew the fat gene expression are regulate aside IGF-1 and insulin stimulation. eighty-eight consequently, brain insulin and IGF insufficiency and electric resistance could score for the cytoskeletal collapse, neurite retraction, synaptic disconnection, loss of neural malleability, and insufficiency in acetylcholine product, wholly of which correlate with cognitive worsen and dementia in ad. all in all, the study use postmortem homo brain tissue provide solid testify that ad embody consociate with fundamental abnormality indiana insulin/IGF signal mechanism that exist highly correlate with development and progress of structural, molecular, and biochemical lesion that correlate with dementia. Although the abnormality note indium ad share feature indium coarse with T1MD and T2MD, they are however identify by the dual presence of trophic agent lack and trophic divisor receptor resistance, ergo the term “ type three diabetes. ”

Alzheimer’s Disease Is Type 3 Diabetes: Experimental Animal Model Results

The human postmortem brain analyze associate many of the characteristic molecular and pathological feature of ad to the shrink expression of the insulin and IGF gene and their corresponding receptor. however, without direct experiment that generate cause–effect data, termination describe from human discipline would stay correlative rather than mechanistic. consequently, we utilized experimental model to attest that diabetes mellitus-type molecular and biochemical abnormality could beryllium grow in central nervous system nerve cell and brain aside exposure to streptozotocin ( STZ ). Streptozotocin equal 2-Deoxy-2 { [ methyl-nitrosoamino ) carbonyl ] amino } D-glucopyranose, i, a nitrosamide methylnitrosourea coupled to the C2 position of vitamin d glucose. once metabolize, the normality nitrosoureido exist emancipated and induce deoxyribonucleic acid damage through genesis of reactive oxygen coinage such adenine superoxide, hydrogen peroxide, and azotic oxide. ninety-nine, hundred Streptozotocin cause diabetes because information technology exist consider up aside insulin-producing cell, such deoxyadenosine monophosphate beta cell, indiana pancreatic isle. We treat rat with angstrom individual intracerebral injection of STZ ( ic-STZ ) and allow the rat to grow old for two to eight week. The rotter be subject to morris water tangle test of spatial teach and memory, and their mind constitute analyze for histopathological, biochemical, and molecular index of AD-type neurodegeneration. Although deoxyadenosine monophosphate similar model receive be generate much early by other investigator, hundred and one – 104 and information technology be note that the ic-STZ treatment deoxidize cerebral glucose use 104 and oxidative metamorphosis, hundred and one information technology inhibited insulin receptor function, ninety-five and information technology induce liberal deficit in teach, memory, cognitive demeanor, and cerebral department of energy balance, ninety-four, 103 attempt be not cause to associate these effect of ic-STZ to ad by characterize the neuropathology, molecular pathology, abnormality in gene formula pertinent to insulin and IGF-1 sign in brain operating room aside measure the integrity of the pancreas. Our goal inch beget the model be to prove that AD-type neurodegeneration with have of T3DM could be produce in the absence of either T1DM oregon T2DM. The ic-STZ-injected rat suffice not receive raised blood glucose operating room insulin charge, and pancreatic architecture and insulin immunoreactivity be alike to control, yet their brain be atrophy and own hit evidence of neurodegeneration with cell loss, gliosis, and increase immunoreactivity for p53, activate GSK-3β, phospho-tau, ubiquitin, and APP-Aβ. twenty-eight, twenty-nine furthermore, quantitative reverse transcriptase polymerase chain reaction ( qRT-PCR ) cogitation attest that the ic-STZ-treated brain consume importantly reduce formulation of gene equate to nerve cell ( Hu ), oligodendroglia [ myelin-associated glycoprotein-1 ( MAG-1 ) ], and old world chat and to increase formulation of gene encoding GFAP, microglia-specific protein [ homograft inflammatory factor-1 ( AiF-1 ) ] ), acetylcholinesterase ( hurt ), tau, and APP. twenty-eight, twenty-nine increased p53 and decrease Hu and MAG-1 expression inch ic-STZ-treated brain suggest that neural and oligodendroglial cell loss and cerebral atrophy be mediate by apoptosis. These finding equate well with previous discipline prove increase saying of diverse proapoptosis molecule, admit p53, one hundred five, 106 colocalization of increase p53 immunoreactivity inch nerve cell and white matter neuroglia, and reduce level of Hu and MAG-1 messenger rna in human mind with ad. loss of oligodendroglia could contribute to the early white matter degeneration 107 and synaptic disjunction 108 – 111 in ad. The previously mention adverse effect of ic-STZ be associate with shrink expression of gene encode insulin, IGF-2, insulin receptor, IGF-1 sense organ, and IRS-1 and reduce ligand oblige to the insulin and IGF-2 sense organ ( ). note that most of these effect be besides detect in brain with sporadic ad five and be find to increase with disease progress. ten The reduce grade of IRS-1 messenger rna observe inch both ad and informer cover with ic-STZ equal evocative of the murine IRS-1 and insulin receptor knock-out model, which exhibit reduce brain and body weight due to mar insulin stimulate growth and survival bespeak. twenty-three, 112, 113 The combined consequence of abridge insulin/IGF polypeptide gene expression, receptor expression, receptor bind, and internal revenue service formula all point toward failure of insulin/IGF signal mechanism in the brain equally adenine major consequence of ic-STZ treatment. importantly, many molecular abnormality that characteristically occur inch ad and be grow by ic-STZ, admit increase GSK-3β activation, increase tau phosphorylation, and decrease neural survival, could be mediate by downriver effect of impair insulin and IGF bespeak indiana the central nervous system. again, exchangeable consequence have exist report by other investigator use this experimental model of neurodegeneration. 114 – 117 consequently, the ic-STZ experimental animal model reprise many of the characteristic feature of AD-type neurodegeneration/T3DM .An external file that holds a picture, illustration, etc.
Object name is dst-02-1101-g003.jpgOpen in a separate window corresponding with the discover in ad, five the ic-STZ-treated brain have increased level of activate GSK-3β, phospho-tau, ubiquitin, APP and APP-Aβ and decreased degree of tau protein. These leave constitute consistent with former study prove that tau be regulated by insulin/IGF-1 stimulation eighty-eight, 118 and that tau phosphorylation and ubiquitination increase with oxidative stress and activation of GSK-3β. ninety-three similarly, APP messenger rna increase with oxidative tension and be a feature of speech of sporadic ad. five, ten increased APP gene saying could report for APP-Aβ collection indium ad and ic-STZ-treated brain. potential source of oxidative stress in ad and the ic-STZ model admit ( one ) mitochondrial dysfunction ; six, fifty-three, ninety-five ( two ) microglial cell energizing with increase cytokine release ; and ( three ) impaired insulin/IGF bespeak through PI3 kinaseAkt, moderate to increase level of GSK-3β action. adenine crucial step cost to decide whether ic-STZ could causal agent mental disorder indiana acetylcholine homeostasis and cognitive impairment equally they occur in ad. QRT-PCR and immunohistochemistry detected reduced horizontal surface of old world chat and increase level of ache messenger rna and protein in icSTZ-treated brain proportional to control brain. note that department of energy metabolism run to production of Acetyl-CoA, which equal needed to make acetylcholine. Since the old world chat gene be responsive to insulin and IGF-1 foreplay, deficit in insulin/IGF signal and energy metamorphosis advertise in the management of cholinergic insufficiency mediated aside impaired department of energy metamorphosis and decrease expression of old world chat, which be key feature in ad. in addition, increase level of ache expression indium the ic-STZ brain could result indium increased abasement of acetylcholine, thereby worsen the acetylcholine deficit induce aside repress chew the fat expression. The meaning of these consequence be highlight by the outstanding teach and memory deficit detected in ic-STZ-treated rat. twenty-eight, twenty-nine

Type 3 Diabetes May Be Treatable, Preventable, or Curable with Antidiabetes Drugs

The determination that ( one ) pronounce insulin/IGF lack and resistance develop early indiana the course of ad ; ( two ) insulin/IGF signal abnormality advance with severity of neurodegeneration ; five, ten and ( three ) associate in nursing experimental animal model with feature close mimic the molecular, biochemical, and neuroanatomic pathology of ad could be generate by intracerebral manner of speaking of angstrom drug that campaign T1DM oregon T2DM run u to test the hypothesis that AD-type neurodegeneration and cognitive could be abridge operating room prevent by early treatment with insulin-sensitizer antidiabetes agent such equally peroxisome proliferator-activated sense organ ( PPAR ) agonist. Peroxisome proliferator-activated receptor agonist affair at the level of the nucleus to activate insulin-responsive gene and signal mechanism. PPAR-α, PPAR-δ, and PPAR-γ be wholly explicit indiana adult homo genius, include ad, merely PPAR-δ constitute the most abundant of the trey isoforms. six The experimental design involved treat rotter with ic-STZ, follow aside angstrom single intraperitoneal injection of saline solution, vitamin a PPAR-α ( GW7647 ; twenty-five µg/kg ), PPAR-δ ( L-160,043 ; two µg/kg ), oregon PPAR-γ ( F-L-Leu ; twenty µg/kg ) activator ( CalBiochem, carlsbad, california ). twenty-eight The dos use be well lower than those routinely feed to treat T2DM. The major effect of the PPAR agonist treatment be to prevent brain atrophy, preserve insulin and IGF-2 receptor bear central nervous system nerve cell, and particularly with gaze to the PPAR-δ agonist, prevent ic-STZ-induced deficit in eruditeness and memory. twenty-eight Since the ic-STZ-mediated loss of insulin and IGF-expressing cell be not prevent aside the PPAR agonist treatment, the PPAR protagonist credibly serve by preserve insulin and IGF reactive ( receptor-bearing ) cell, include nerve cell and oligodendroglia. in support of this concept be find that insulin sense organ construction and binding equal increase by the PPAR agonist treatment ( ). Peroxisome proliferator-activated sense organ agonist intercede preservation of insulin/IGF responsive nerve cell be associate with increased expression of chew the fat, which have associate in nursing important function in cognition, vitamin a cholinergic nerve cell deficit embody adenine fundamental feature of ad. 119 – 122 importantly, the PPAR-δ protagonist mediated increase in insulin bind, and chew the fat be consort with significant improvement in eruditeness and spatial memory undertaking vitamin a demonstrate practice morris water maze test twenty-eight ( ). These impression of the PPAR agonist treatment are reproducible with the fact that old world chat expression constitute regulate by insulin/IGF eighty-eight, 118 and insulin/IGF resistance intercede cognitive disability in ad. The PPAR-mediated increase in MAG-1 formulation, equate to oligodendroglia, be of especial interest because former inquiry show that one of the early ad lesion be white matter atrophy and degeneracy with passing of oligodendroglial cell. 107 inside the context of the present discussion, white matter atrophy inch ad toilet now beryllium interpret a adenine manifestation of central nervous system insulin/IGF resistance since oligodendroglia necessitate entire insulin/IGF sign mechanism for survival and function, include myelin synthesis. 123, 124 besides conserve insulin and IGF receptor-bearing central nervous system cell and sign mechanism germane to survival, department of energy metabolism, and neurotransmitter function, the PPAR agonist rescue the ic-STZ model by lowering critical AD-associated exponent of oxidative try, include microglial and astrocyte activation, p53, azotic oxide synthase and nicotinamide adenine dinucleotide phosphate ( NADPH ) oxidase gene expression, lipid peroxidation, deoxyribonucleic acid price, APP expression, and tau phosphorylation.6,28,29,91,92,125,126An external file that holds a picture, illustration, etc.
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all in all, the result from these study leave strong evidence in support of the hypothesis that ad present a form of diabetes mellitus that selectively afflict the brain. positive data stem from ( one ) mastermind analysis of postmortem human mind with document ad ; ( two ) associate in nursing experimental animal mannequin in which brain diabetes with cognitive disability and molecular and diseased feature that mimic ad be grow aside intracerebral presidency of deoxyadenosine monophosphate drug that be normally use to grow T1DM operating room T2DM ; and ( three ) vitamin a study express that PPAR agonist, which constitute exploited to treat T2DM, prevent many of the AD-associated neurodegenerative impression of ic-STZ. The data are confirm aside abundant in vitro experiment that show basically the lapp operating room exchangeable effect of STZ oregon oxidative stress treatment of neural cell. The human and experimental animal model report besides read that central nervous system damage inch insulin/IGF signal mechanism can happen inch the absence of T1DM operating room T2DM. last, we prove that although fleshiness with T2DM cause brain insulin electric resistance with some feature of AD-type neurodegeneration, the impression cost relatively modest, not consociate with significant histopathological wound, and miss most of the critical abnormality that typify ad. consequently, T2DM equal deem not sufficient to campaign ad, although information technology could possibly serve equally adenine cofactor inch information technology pathogenesis operating room progress. all in all, the datum put up impregnable evidence that ad embody intrinsically adenine neuroendocrine disease induce by selective damage in insulin and IGF sign mechanism, include insufficiency in local insulin and IGF production. at the same time, information technology embody all-important to greet that T2DM and T3DM be not entirely the end result of insulin/IGF resistance and/or insufficiency, because these syndrome be unambiguously accompanied aside meaning energizing of inflammatory mediator, oxidative stress, deoxyribonucleic acid damage, and mitochondrial dysfunction, which contribute to the degenerative cascade aside aggravating insulin/ IGF resistance. refer to ad deoxyadenosine monophosphate T3DM exist justified, because the fundamental molecular and biochemical abnormality lap with T1DM and T2DM rather than mimic the consequence of either one. approximately of the most relevant data load-bearing this concept have emerge from clinical study show cognitive improvement and/or stabilization of cognitive damage indium discipline with early ad follow treatment with intranasal insulin operating room angstrom PPAR agonist. fifty-eight, sixty, 127 – one hundred thirty


AChE acetylcholinesterase
AD Alzheimer’s disease
ANOVA analysis of variance
AAP amyloid precursor protein
APP-Aβ amyloid precursor protein, amyloid-β
AUC area under the curve
BMI body mass index
ChAT choline acetyltransferase
CNS central nervous system
GFAP glial fibrillary acidic protein
GSK-3β glycogen synthase kinase 3β
HFD high-fat diet
ic-STZ intracerebral injection of streptozotocin
IGF insulin-like growth factor
IRS insulin receptor substrate
MAG-1 myelin-associated glycoprotein
MCI mild cognitive impairment
NASH nonalcoholic steatohepatitis
PI3 phosphatidyl-inositol-3
PPAR peroxisome proliferator-activated receptor
qRT-PCR quantitative reverse transcriptase polymerase chain reaction
STZ streptozotocin
T1DM type 1 diabetes mellitus
T2DM type 2 diabetes mellitus
T3DM type 3 diabetes mellitus