Alzheimer Disease: Maryland

McKhann GM, Albert MS, Grossman M, Miller B, Dickson D, Trojanowski JQ, Anonymous00019. · Department of Neurology, Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University School of Medicine, 338 Krieger Hall, 3400 N Charles St, Baltimore, MD 21218-2685, USA. · Arch Neurol. · Pubmed #11708987 links to  free full text

Abstract: An international group of clinical and basic scientists participated in the Frontotemporal Dementia and Pick's Disease Criteria Conference at the National Institutes of Health in Bethesda, Md, on July 7, 2000, to reassess clinical and neuropathological criteria for the diagnosis of frontotemporal dementia (FTD). Previous criteria for FTD have primarily been designed for research purposes. The goal of this meeting was to propose guidelines that would enable clinicians (particularly neurologists, psychiatrists, and neuropsychologists) to recognize patients with FTD and, if appropriate, to expedite their referral to a diagnostic center. In addition, recommendations for the neuropathological criteria of FTD were reviewed, relative to classical neuropathology and modern molecular biology.

Martin BK, Breitner JC, Evans D, Lyketsos CG, Meinert CL. · Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Md, USA. · Am J Med. · Pubmed #17349436 No free full text.

This publication has no abstract.

Radebaugh TS, Ward-Robinson J. · Khachaturian, Radebaugh & Associates, Inc., Patomac, Maryland 20854-3009, USA. · Alzheimer Dis Assoc Disord. · Pubmed #12351912 No free full text.

This publication has no abstract.

Petanceska S, Ryan L, Silverberg N, Buckholtz N. · Division of Neuroscience, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA. · Alzheimers Dement. · Pubmed #19328442 No free full text.

This publication has no abstract.

Fotuhi M, Mohassel P, Yaffe K. · Center for Memory and Brain Health, LifeBridge Health Brain & Spine Institute, Sinai Hospital of Baltimore, Baltimore, MD 21209, USA. · Nat Clin Pract Neurol. · Pubmed #19262590 No free full text.

Abstract: Long-chain omega-3 fatty acids could have neuroprotective properties against dementia, which is becoming a major global public health issue. We conducted a systematic review of the literature to establish the association between eating fish (a source of long-chain omega-3 fatty acids) or taking long-chain omega-3 fatty acid supplements and the risk of cognitive decline or Alzheimer disease (AD). We identified eleven observational studies and four clinical trials. All three observational studies that used cognitive decline as an outcome reported significant benefits, whereas only four of eight observational studies that used incidence of AD or dementia as an outcome reported positive findings. None of four small clinical trials provided convincing evidence for the use of this approach in the prevention or treatment of any form of dementia. In summary, the existing data favor a role for long-chain omega-3 fatty acids in slowing cognitive decline in elderly individuals without dementia, but not for the prevention or treatment of dementia (including AD). This apparent dichotomy might reflect differences in study designs with regard to participants, dosages, the ratio of long-chain omega-3 to omega-6 fatty acids, or the choice of outcome measurements. Large clinical trials of extended duration should help to provide definitive answers.

Manolio TA. · National Human Genome Research Institute, Building 31, Room 4B-09, 31 Center Drive, MSC 2154, Bethesda, MD 20892-2154, USA. · Pharmacogenomics. · Pubmed #19207024 No free full text.

Abstract: In the past 3 years, genome-wide association (GWA) studies have revolutionized the discovery of genetic variants associated with complex diseases. These studies present unique challenges in their conduct; particularly in the need for meticulous quality control of genotyping and for sample sizes large enough to withstand the severe penalty for multiple comparisons necessitated by testing hundreds of thousands of SNPs. They also present unique opportunities in the unprecedented detail with which they characterize an individual's genome and the potential for relating that information to any trait consistent with that person's informed consent. Such data exceed the abilities of any single group of investigators to mine them fully and by NIH policy are distributed to qualified investigators agreeing to specified terms of use. This report describes collaborative programs of the National Human Genome Research Institute's Office of Population Genomics for facilitating collection, analysis, interpretation, and dissemination of these data so that their research value can be maximized.

Shie FS, Nivison M, Hsu PC, Montine TJ. · Division of Mental Health and Substance Abuse Research, National Health Research Institutes, No.35 Keyan Road, Zhunan Town, Miaoli County 350, Taiwan, R.O.C. · Curr Med Chem. · Pubmed #19199928 No free full text.

Abstract: Alzheimer's disease (AD) is the leading cause of dementia in the elderly. Although the etiology of AD remains unclear, microglia-mediated neuroinflammation is believed to play an important role in its pathogenesis. Microglial activation occurs in AD and is characterized by apparent phagocytic activity and by increased production and secretion of several cytokines, chemokines, reactive oxygen and nitrogen species, prostaglandin (PG)E2, and neurotrophic factors. Microglial activation can be neuroprotective through the release of neurotrophic factors and by phagocytosing Abeta, a critical neurotoxic component in AD brain. Concurrently, microglial activation causes elevated inflammatory responses that lead to paracrine damage to neurons. Therefore, a well-controlled microglial activation that diminishes microglial-mediated oxidative damage while promoting neuronal protection may be the key for AD therapy. Peroxisome proliferator-activated receptor gamma (PPARgamma) has recently gained increasing attention in AD due to its function as a molecular target for non-steroidal anti-inflammatory drugs (NSAIDs). In this review, we will discuss the role of PPARgamma in microglial innate immunity in AD and how pharmacological manipulation of microglial activation using PPARgamma ligands might facilitate the treatment of AD.

Becker RE, Unni LK, Greig NH. · Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA. · Curr Alzheimer Res. · Pubmed #19199879 No free full text.

Abstract: Commercial priorities have been identified as negative factors in drug development. We trace the problem to inattention to sound clinical pharmacology practices. When properly applied, clinical pharmacology and associated drug development sciences can, hand in hand, facilitate success in commercial drug development.

Albuquerque EX, Pereira EF, Alkondon M, Rogers SW. · Department of Pharmacology and Experimental Therapeutics, University of Maryland School of Medicine, Baltimore, MD, USA. · Physiol Rev. · Pubmed #19126755 links to  free full text

Abstract: The classical studies of nicotine by Langley at the turn of the 20th century introduced the concept of a "receptive substance," from which the idea of a "receptor" came to light. Subsequent studies aided by the Torpedo electric organ, a rich source of muscle-type nicotinic receptors (nAChRs), and the discovery of alpha-bungarotoxin, a snake toxin that binds pseudo-irreversibly to the muscle nAChR, resulted in the muscle nAChR being the best characterized ligand-gated ion channel hitherto. With the advancement of functional and genetic studies in the late 1980s, the existence of nAChRs in the mammalian brain was confirmed and the realization that the numerous nAChR subtypes contribute to the psychoactive properties of nicotine and other drugs of abuse and to the neuropathology of various diseases, including Alzheimer's, Parkinson's, and schizophrenia, has since emerged. This review provides a comprehensive overview of these findings and the more recent revelations of the impact that the rich diversity in function and expression of this receptor family has on neuronal and nonneuronal cells throughout the body. Despite these numerous developments, our understanding of the contributions of specific neuronal nAChR subtypes to the many facets of physiology throughout the body remains in its infancy.

Mattson MP. · Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA. · Ann N Y Acad Sci. · Pubmed #19076369 links to  free full text

Abstract: Glutamate's role as a neurotransmitter at synapses has been known for 40 years, but glutamate has since been shown to regulate neurogenesis, neurite outgrowth, synaptogenesis, and neuron survival in the developing and adult mammalian nervous system. Cell-surface glutamate receptors are coupled to Ca(2+) influx and release from endoplasmic reticulum stores, which causes rapid (kinase- and protease-mediated) and delayed (transcription-dependent) responses that change the structure and function of neurons. Neurotrophic factors and glutamate interact to regulate developmental and adult neuroplasticity. For example, glutamate stimulates the production of brain-derived neurotrophic factor (BDNF), which, in turn, modifies neuronal glutamate sensitivity, Ca(2+) homeostasis, and plasticity. Neurotrophic factors may modify glutamate signaling directly, by changing the expression of glutamate receptor subunits and Ca(2+)-regulating proteins, and also indirectly by inducing the production of antioxidant enzymes, energy-regulating proteins, and antiapoptotic Bcl-2 family members. Excessive activation of glutamate receptors, under conditions of oxidative and metabolic stress, may contribute to neuronal dysfunction and degeneration in diseases ranging from stroke and Alzheimer's disease to psychiatric disorders. By enhancing neurotrophic factor signaling, environmental factors such as exercise and dietary energy restriction, and chemicals such as antidepressants may optimize glutamatergic signaling and protect against neurological disorders.

Mattson MP, Ashery U. · Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA. · Trends Biochem Sci. · Pubmed #19008105 links to  free full text

Abstract: In Alzheimer's disease (AD), neurons suffer dysfunction and death associated with aberrant tau phosphorylation and subsequent neurofibrillary tangles. A new study reveals a surprising neuroprotective role for a truncated p73 isoform (DeltaNp73). Aged mice with reduced DeltaNp73 levels exhibit tau pathology and cognitive deficits, and DeltaNp73 reduction in mice with amyloid pathology causes extensive tangle formation and neuron death. These findings provide a novel animal model of AD and a potential therapeutic role for DeltaNp73 inducers.

Rapoport SI. · Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Building 9, Room 1S128, 9 Memorial Drive, Bethesda, MD 20892, USA. · Prostaglandins Leukot Essent Fatty Acids. · Pubmed #18973997 No free full text.

Abstract: Metabolic cascades involving arachidonic acid (AA) and docosahexaenoic acid (DHA) within brain can be independently targeted by drugs, diet and pathological conditions. Thus, AA turnover and brain expression of AA-selective cytosolic phospholipase A(2) (cPLA(2)), but not DHA turnover or expression of DHA-selective Ca(2+)-independent iPLA(2), are reduced in rats given agents effective against bipolar disorder mania, whereas experimental excitotoxicity and neuroinflammation selectively increase brain AA metabolism. Furthermore, the brain AA and DHA cascades are altered reciprocally by dietary n-3 polyunsaturated fatty acid (PUFA) deprivation in rats. DHA loss from brain is slowed and iPLA(2) expression is decreased, whereas cPLA(2) and COX-2 are upregulated, as are brain concentrations of AA and its elongation product, docosapentaenoic acid (DPA). Positron emission tomography (PET) has shown that the normal human brain consumes 17.8 and 4.6 mg/day, respectively, of AA and DHA, and that brain AA consumption is increased in Alzheimer disease patients. In the future, PET could help to determine how human brain AA or DHA consumption is influenced by diet, aging or disease.

Becker RE, Greig NH, Giacobini E. · Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA. · J Alzheimers Dis. · Pubmed #18953116 No free full text.

Abstract: Alzheimer's disease (AD) drug developments and clinical trials (CT) remain vulnerable to problems that undermine research validity. Investigations of CT methods reveal how numerous factors decrease active drug-placebo group differences and increase variance, thereby reducing power to reach statistical significance for outcome measure differences in AD CTs. Such factors include, amongst many, inaccuracy, imprecision, bias, failures to follow or lack of operational protocols for applying CT methods, inter-site variance, and lack of homogeneous sampling using disorder criteria. After a review of the literature and survey of a sample of AD and Mild Cognitive Impairment (MCI) CTs, the authors question whether problems of human error preclude AD researchers from continuing their dependence on rated outcome measures for CTs. The authors propose that the realities of AD, especially a probable irreversible progression of neuropathology prior to onset of clinical symptoms or signs capable of differentiating persons at risk for AD from normal aged, require AD investigators and clinicians to privilege biomarkers and encourage their development as surrogate targets for preventive AD treatment developments, testing, and use in clinical practice.

Lee HB, DeLoatch CJ, Cho S, Rosenberg P, Mears SC, Sieber FE. · Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21287-5371, USA. · Crit Care Clin. · Pubmed #18929940 No free full text.

Abstract: Recent increase in both the elderly population and associated incidence of dementia are of critical importance to patient care in ICUs in the United States. Identification of pre-existing cognitive impairment, such as mild cognitive impairment and dementia, could prevent delirium and associated morbidity and mortality in the ICU. Additionally, noncognitive behavioral symptoms, such as depression, psychosis, agitation, and catastrophic reactions, are common in patients with pre-existing cognitive impairment. Detection and management of noncognitive behavioral symptoms associated with MRI and dementia in ICU leads to improved delivery of life-saving critical care.

Becker RE, Greig NH. · Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA. · Curr Alzheimer Res. · Pubmed #18690832 links to  free full text

Abstract: Recently, a number of Alzheimer's disease (AD) multi-center clinical trials (CT) have failed to provide statistically significant evidence of drug efficacy. To test for possible design or execution flaws we analyzed in detail CTs for two failed drugs that were strongly supported by preclinical evidence and by proven CT AD efficacy for other drugs in their class. Studies of the failed commercial trials suggest that methodological flaws may contribute to the failures and that these flaws lurk within current drug development practices ready to impact other AD drug development [1]. To identify and counter risks we considered the relevance to AD drug development of the following factors: (1) effective dosing of the drug product, (2) reliable evaluations of research subjects, (3) effective implementation of quality controls over data at research sites, (4) resources for practitioners to effectively use CT results in patient care, (5) effective disease modeling, (6) effective research designs. New drugs currently under development for AD address a variety of specific mechanistic targets. Mechanistic targets provide AD drug development opportunities to escape from many of the factors that currently undermine AD clinical pharmacology, especially the problems of inaccuracy and imprecision associated with using rated outcomes. In this paper we conclude that many of the current problems encountered in AD drug development can be avoided by changing practices. Current problems with human errors in clinical trials make it difficult to differentiate drugs that fail to evidence efficacy from apparent failures due to Type II errors. This uncertainty and the lack of publication of negative data impede researchers' abilities to improve methodologies in clinical pharmacology and to develop a sound body of knowledge about drug actions. We consider the identification of molecular targets as offering further opportunities for overcoming current failures in drug development.

Castellani RJ, Nunomura A, Lee HG, Perry G, Smith MA. · Department of Pathology, University of Maryland, Baltimore, MD, USA. · J Alzheimers Dis. · Pubmed #18688087 No free full text.

Abstract: Identification of phosphorylated tau as the major protein component of neurofibrillary tangles (NFTs) led to the concept that phosphorylated tau was inherently toxic and, as such, intimately involved in Alzheimer's disease (AD) pathogenesis. While superficially logical, this construct ignores a number of key findings in AD, including i) that NFTs are encountered in viable neurons until late stage disease; ii) that NFTs persist within the neuronal cytoplasm for decades; iii) that NFTs are encountered, sometimes in significant numbers, in cognitively intact elderly; and iv) that neurons with NFTs contain normal content and structure of microtubules. Experimental data in transgenic animal models has further demonstrated that NFTs accumulate in neurons in spite of tau suppression and behavior normalization. These data call into question the inherent toxicity of phosphorylated tau, seemingly leaving the only viable hypothesis of the ad hoc "toxic intermediate" phosphorylated tau concept. However, since we also know that phosphorylated tau sequesters redox active heavy metals and protects against oxidative stress, here we suggest that phosphorylated tau serves a protective role against cellular toxicity.

Hodes RJ, Buckholtz N, Cahan V, Morrison-Bogorad M. · National Institute on Aging, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD, USA. · Alzheimers Dement. · Pubmed #18631998 No free full text.

Abstract: The public Alzheimer's disease (AD) research enterprise began in earnest in the mid-1970s with the creation by Congress of the National Institute on Aging at the National Institutes of Health. Today, AD research is a maturing field of study, with federal effort seeking to encourage the creativity and insights of individual investigators, and targeting special areas for emphasis. It is inspired by the legacy of our friend and colleague Leon Thal, whose innovative and collaborative approach to scientific research serves as a guidepost as we move toward the discovery of new and effective ways to prevent AD or slow its progression. This article describes the progress to date and potentially promising areas of study from the vantage point of the National Institute on Aging.

Oh ES, Troncoso JC, Fangmark Tucker SM. · Department of Medicine, The Johns Hopkins University School of Medicine, 558 Ross Research Building, 720 Rutland Ave., Baltimore, MD 21205, USA. · Neuromolecular Med. · Pubmed #18543125 links to  free full text

Abstract: Amyloid plaques are composed primarily of amyloid-beta (Abeta) peptides derived from proteolytic cleavage of amyloid precursor protein (APP) and are considered to play a pivotal role in Alzheimer's disease (AD) pathogenesis. Presently, AD is diagnosed after the onset of clinical manifestations. With the arrival of novel therapeutic agents for treatment of AD, there is an urgent need for biomarkers to detect early stages of AD. Measurement of plasma Abeta has been suggested as an inexpensive and non-invasive tool to diagnose AD and to monitor Abeta modifying therapies. However, the majority of cross-sectional studies on plasma Abeta levels in humans have not shown differences between individuals with AD compared to controls. Similarly, cross-sectional studies of mouse plasma Abeta have yielded inconsistent trends in different mouse models. However, longitudinal studies appear to be more promising in humans. Recently, efforts to modify plasma Abeta levels using modulators have shown some promise. In this review, we will summarize the present data on plasma Abeta in humans and mouse models of AD. We will discuss the potential of modulators of Abeta levels in plasma, including antibodies and insulin, and the challenges associated with measuring plasma Abeta. Modulators of plasma Abeta may provide an important tool to optimize plasma Abeta levels and may improve the diagnostic potential of this approach.

Castellani RJ, Lee HG, Zhu X, Perry G, Smith MA. · Department of Pathology, University of Maryland, Baltimore, Maryland, USA. · J Neuropathol Exp Neurol. · Pubmed #18520771 No free full text.

Abstract: Identification of amyloid-beta and tau as the major protein components of senile plaques and neurofibrillary tangles, respectively, led to an exponential increase in investigations of these proteins and their corresponding metabolic pathways in Alzheimer disease (AD). The presumptions inherent in most studies and in the dogma of the amyloid cascade concept are that these hallmark lesions in AD brains contain molecules that drive the disease process, and that the proteinaceous accumulations are themselves toxic. On the other hand, the lesions of AD are, by definition, end-stage, and their relationship to the clinical disease is inconsistent; this has long been known but, generally, has not been acknowledged until relatively recently. Some recent attempts to address the etiology and pathogenesis of AD discard the pathology and focus on the interplay between invisible toxic intermediates, that is, amyloid-beta oligomers and the synapse. The concept that the hallmark lesions may be nontoxic (something we have long suggested) is slowly gaining acceptance. We favor the interpretation that senile plaques and neurofibrillary tangles represent a host response to an upstream pathophysiologic process, and that the therapeutic targeting of lesions, including toxic intermediates, will succeed only in the event that the host response is directly deleterious. Therefore, renewed efforts aimed at elucidating fundamental age-related processes such as oxidative stress and/or inflammatory mediators are warranted.

Crawley JN. · Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Porter Neuroscience Research, Center Building 35, Room 1C-903, Mail Code 3730, Bethesda, Maryland 20892-3730, USA. · Cell Mol Life Sci. · Pubmed #18500642 links to  free full text

Abstract: The neuropeptide galanin and its receptors are localized in brain pathways mediating learning and memory. Central microinjection of galanin impairs performance of a variety of cognitive tasks in rats. Transgenic mice overexpressing galanin display deficits in some learning and memory tests. The inhibitory role of galanin in cognitive processes, taken together with the overexpression of galanin in Alzheimer's disease, suggests that galanin antagonists may offer a novel therapeutic approach to treat memory loss in Alzheimer's patients.

Lyketsos CG, Szekely CA, Mielke MM, Rosenberg PB, Zandi PP. · Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A. · Int Psychogeriatr. · Pubmed #18498669 No free full text.

Abstract: This synthetic review presents an approach to the use of biomarkers for the development of new treatments for Alzheimer's disease (AD). After reviewing the process of translation as applied to AD, the paper provides a general update on what is known about the biology of the disease, and highlights currently available treatments. This is followed by a discussion of future drug development for AD emphasizing the roles that biomarkers are likely to play in this process: (1) define patients who are going to progress rapidly for the purpose of trial enrichment; (2) differentiate disease and therapeutically relevant AD subtypes; (3) assess the potential activity of specific therapies in vivo or ex vivo; and (4) measure the underlying disease state, so as to (a) detect disease and assess drug response in asymptomatic patients, (b) serve as a secondary outcome measure in clinical trials of symptomatic patients, and (c) decide if further development of a treatment should be stopped if not likely to be effective. Several examples are used to illustrate each biomarker utility in the AD context.

Yang JL, Weissman L, Bohr VA, Mattson MP. · Laboratory of Molecular Gerontology, National Institute on Aging Intramural Research Program, Baltimore, MD, USA. · DNA Repair (Amst). · Pubmed #18463003 links to  free full text

Abstract: By producing ATP and regulating intracellular calcium levels, mitochondria are vital for the function and survival of neurons. Oxidative stress and damage to mitochondrial DNA during the aging process can impair mitochondrial energy metabolism and ion homeostasis in neurons, thereby rendering them vulnerable to degeneration. Mitochondrial abnormalities have been documented in all of the major neurodegenerative disorders-Alzheimer's, Parkinson's and Huntington's diseases, and amyotrophic lateral sclerosis. Mitochondrial DNA damage and dysfunction may be downstream of primary disease processes such as accumulation of pathogenic proteins. However, recent experimental evidence demonstrates that mitochondrial DNA damage responses play important roles in aging and in the pathogenesis of neurodegenerative diseases. Therapeutic interventions that target mitochondrial regulatory systems have been shown effective in cell culture and animal models, but their efficacy in humans remains to be established.

Martin LJ. · Department of Pathology, Division of Neuropathology, and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA. · J Neuropathol Exp Neurol. · Pubmed #18431258 links to  free full text

Abstract: DNA damage is a form of cell stress and injury that has been implicated in the pathogenesis of many neurologic disorders, including amyotrophic lateral sclerosis, Alzheimer disease, Down syndrome, Parkinson disease, cerebral ischemia, and head trauma. However, most data reveal only associations, and the role for DNA damage in direct mechanisms of neurodegeneration is vague with respect to being a definitive upstream cause of neuron cell death, rather than a consequence of the degeneration. Although neurons seem inclined to develop DNA damage during oxidative stress, most of the existing work on DNA damage and repair mechanisms has been done in the context of cancer biology using cycling nonneuronal cells but not nondividing (i.e. postmitotic) neurons. Nevertheless, the identification of mutations in genes that encode proteins that function in DNA repair and DNA damage response in human hereditary DNA repair deficiency syndromes and ataxic disorders is establishing a mechanistic precedent that clearly links DNA damage and DNA repair abnormalities with progressive neurodegeneration. This review summarizes DNA damage and repair mechanisms and their potential relevance to the evolution of degeneration in postmitotic neurons.

Shah RS, Lee HG, Xiongwei Z, Perry G, Smith MA, Castellani RJ. · Department of Neurology, University of Maryland, Baltimore, MD 21201, USA. · Biomed Pharmacother. · Pubmed #18407457 No free full text.

Abstract: The management of Alzheimer's disease (AD) has been a long-standing challenge and area of interest. Advances in knowledge of the pathogenesis of disease and an increase in disease burden have prompted investigation into innovative therapeutics over the last two decades. This article reviews the various treatments of AD including those targeted towards cholinergic deficiency, oxidative stress, the amyloid cascade, inflammation, and excitotoxicity. Second generation cholinesterase inhibitors remain the preferred therapy for early and intermediate AD while the glutamate antagonist, memantine, is also approved for advanced stages of disease. Antioxidants may delay disease progression, while data on other experimental therapies remain equivocal at best. Gene therapy directed at neurotropins is currently under investigation with some intriguing preliminary results; however, the number of patients examined is too few to be conclusive. Drugs directly targeting amyloid-beta, particularly the amyloid-beta vaccine, continue to be investigated and their forthcoming results are eagerly anticipated.

Nelson TJ, Sun MK, Hongpaisan J, Alkon DL. · Blanchette Rockefeller Neurosciences Institute, 9601 Medical Center Drive, Rockville, Maryland 20850 USA. · Eur J Pharmacol. · Pubmed #18402935 No free full text.

Abstract: Protein kinase C (PKC) is involved in synaptic remodeling, induction of protein synthesis, and many other processes important in learning and memory. Activation of neuronal protein kinase C correlates with, and may be essential for, all phases of learning, including acquisition, consolidation, and reconsolidation. Protein kinase C activation is closely tied to hydrolysis of membrane lipids. Phospholipases C and A2 produce 1,2-diacylglycerol and arachidonic acid, which are direct activators of protein kinase C. Phospholipase C also produces inositol triphosphate, which releases calcium from internal stores. Protein kinase C interacts with many of the same pathways as insulin; therefore, it should not be surprising that insulin signaling and protein kinase C activation can both have powerful effects on memory storage and synaptic remodeling. However, investigating the possible roles of insulin in memory storage can be challenging, due to the powerful peripheral effects of insulin on glucose and the low concentration of insulin in the brain. Although peripheral for insulin, synthesized in the beta-cells of the pancreas, is primarily involved in regulating glucose, small amounts of insulin are also present in the brain. The functions of this brain insulin are inadequately understood. Protein kinase C may also contribute to insulin resistance by phosphorylating the insulin receptor substrates required for insulin signaling. Insulin is also responsible insulin-long term depression, a type of synaptic plasticity that is also dependent on protein kinase C. However, insulin can also activate PKC signaling pathways via PLC gamma, Erk 1/2 MAP kinase, and src stimulation. Taken together, the available evidence suggests that the major impact of protein kinase C and its interaction with insulin in the mature, fully differentiated nervous system appears to be to induce synaptogenesis, enhance memory, reduce Alzheimer's pathophysiology, and stimulate neurorepair.