In Alzheimer's disease, neuronal degeneration due to apoptosis has been linked to overexpression and aberrant amyloidogenic processing of the amyloid precursor protein (APP), as well as to bioenergetic defects characterized by deficits in the electron transport chain's cytochrome c oxidase (COX) which leads to the genera ion of radical oxygen species. Inhibition of oxidative energy metabolism increased the amyloidogenic processing of APP, which led to neurotoxicity. Overexpression of APP in cultured normal human muscle fibres caused a specific decrease in COX activity, followed by ultrastructural abnormalities of mitochondria. We have demonstrated, using the yeast two-hybrid system, that APP interacts with COX subunit 1 (COX I), and that this interaction involves the extracellular domain of APP. We demonstrated that APP caused specific deficits in COX activity, induced the production of radical oxygen species and lipid peroxidation, and enhanced neuronal apoptosis. However, anti-oxidant enzyme activity was variable, and probably represented a compensatory reaction to elevated oxygen radicals. To directly interact with COY, APP must be targeted to, and localized in, mitochondria. This possibility was tested with an ' in vitro' mitochondrial import assay which showed that APP is transported to mitochondria in an energy-dependent manner. Furthermore, dual fluorescence microscopy with chimeric APP-green fluorescent protein, and immunoelectron microscopy, demonstrated the presence of endogenous APP and B-amyloid peptide (the neurotoxic cleavage product of APP) in mitochondria of postmortem human brain tissue, with increased levels of B-amyloid peptide in AD brains compared to non-AD brains. (Abstract shortened by UMI.).

This book is based on an international symposium titled "Cytochrome oxidase in energy metabolism and Alzheimer's disease," held as a satellite to the 27th meeting of the Society for Neuroscience, New Orleans, 1997. The symposium was dedicated in honor of Dr. Margaret T. T. Wong-Riley because, in our opinion, the cytochrome oxidase histo chemical method introduced by Dr. Wong-Riley in 1979 was the most significant break through to map energy metabolism in the entire brain since the 2-deoxyglucose method introduced by Dr. Louis Sokoloff and colleagues in 1977. Both of these metabolic map ping techniques have made monumental contributions to brain research by allowing an integral view of brain activity. They have also developed into various specialized tech niques, including applications to the human brain. One of these new applications, which is described in detail in this book, is the quantitative cytochrome oxidase cytochemical method used to study Alzheimer's disease. The objective of this book is to describe the role of cytochrome oxidase in neuronal metabolism and Alzheimer's disease. Whether genetic or environmental, the pathogenesis of Alzheimer's disease involves a cascade of multiple intracellular events, eventually re sulting in failure of oxidative energy metabolism. Could impairment of cytochrome oxi dase in energy metabolism initiate the degenerative process? Cytochrome oxidase function and dysfunction are discussed in relationship to neuronal energy metabolism, neurodegen eration, and Alzheimer's disease. The book is made up of 10 chapters, divided into three major parts.

Methods in Toxicology, Volume 2: Mitochondrial Dysfunction provides a source of methods, techniques, and experimental approaches for studying the role of abnormal mitochondrial function in cell injury. The book discusses the methods for the preparation and basic functional assessment of mitochondria from liver, kidney, muscle, and brain; the methods for assessing mitochondrial dysfunction in vivo and in intact organs; and the structural aspects of mitochondrial dysfunction are addressed. The text also describes chemical detoxification and metabolism as well as specific metabolic reactions that are especially important targets or indicators of damage. The methods for measurement of alterations in fatty acid and phospholipid metabolism and for the analysis and manipulation of oxidative injury and antioxidant systems are also considered. The book further tackles additional methods on mitochondrial energetics and transport processes; approaches for assessing impaired function of mitochondria; and genetic and developmental aspects of mitochondrial disease and toxicology. The text also looks into mitochondrial DNA synthesis, covalent binding to mitochondrial DNA, DNA repair, and mitochondrial dysfunction in the context of developing individuals and cellular differentiation. Microbiologists, toxicologists, biochemists, and molecular pharmacologists will find the book invaluable.

Impairment of energy metabolism is a hallmark of brain aging and several neurodegenerative diseases, such as the Alzheimer’s disease (AD). Age- and disease-related hypometabolism is commonly associated with oxidative stress and they are both regarded as major contributors to the decline in synaptic plasticity and cognition. Neuroinflammatory changes, entailing microglial activation and elevated expression of inflammatory cytokines, also correlate with age-related cognitive decline. It is still under debate whether the mitochondrial dysfunction-induced metabolic deficits or the microglia activation-mediated neuroinflammation is the initiator of the cognitive changes in aging and AD. Nevertheless, multiple lines of evidence support the notion that mitochondrial dysfunction and chronic inflammation exacerbate each other, and these mechanistic diversities have cellular redox dysregulation as a common denominator. This research topic focuses on the role of a metabolic-inflammatory axis encompassing the bioenergetic activity, brain inflammatory responses and their redox regulation in healthy brain aging and neurodegenerative diseases. Dynamic interactions among these systems are reviewed in terms of their causative or in-tandem occurrence and how the systemic environment, –e.g., insulin resistance, diabetes, and systemic inflammation–, impacts on brain function.

Complex and unexplained phenomena tend to foster unorthodox perspectives. This publication is an example, as is a prior publication that emphasized the concept that intermediary metabolism might play a significant and determining role in hepatocyte proliferation and 1 tumorigenesis. Formulation of this hypothesis was based on an attempt to clarify several poorly understood phenomena; including the observations: 1) that xenobiotic peroxisome proliferators such as the fibrate hypolipidemic agents induce hepatocyte proliferation and carcinogenesis in rodents; 2) that benign and malignant liver tumors complicate the human syndrome of glycogen storage disease type I (glucose-6-phosphatase deficiency); and 3) that in this same syndrome, administration of glucose exerts an anti-tumor effect. Fatty acid and glucose metabolism are tightly linked in a we- established and profoundly inportant interplay. This connection, together with the fact that peroxisome proliferator-induced hepatocyte proliferation and carcinogenesis reflects inhibition of mitochondrial carnitine palmitoyltransferase-I and fatty acid oxidation, suggested the possibility that regulation of fatty acid metabolism could prove to be a pivotal determinant in the control of cell growth. In 1993, the year in which the paper cited above was published, insight into the importance of growth factors and signal transduction pathways in cell cycle regulation was increasing rapidly, but metabolic and energetic aspects of cell proliferation had attracted relatively little attention. Despite this, the concept seemed inescapable that the two seemingly distinct and unrelated determinants — signal transduction and metabolism — were integrally linked.

There is solid evidence of abnormalities in oxidative / energy metabolism with neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. The papers contained in this book are an attempt to move studies in this area to a deeper, more mechanistic level.

Understanding the impact of diet, exercise, genetics, and hormones on the risk and development of Alzheimer’s and other neurogenerative diseases Diet is widely known to impact on neurological function. Nevertheless, academic texts discussing this relationship are relatively few in number. This book therefore fills an important gap in the current literature. Opening with an overview of neurodegenerative diseases, particularly Alzheimer’s disease, the text then focuses on explaining the means by which glycemic control and lipid metabolism – and associated nutritional and lifestyle variables – may factor into such disorders’ prevention and treatment. An international group of experts in the fields of food science and neurodegeneration have contributed chapters that examine Alzheimer’s disease within a broad range of contexts. Offering dietary, genetic, and hormonal perspectives, the authors explore topics ranging from sugar consumption to digestive fermentation, and Alzheimer’s disease animal models to the cognition-enhancing effects of physical exercise. Also included are overviews of the latest research into current and developing methods of treatment and diagnosis, as well as differential diagnostics. This groundbreaking book: Explores how glucose metabolism, insulin resistance, lipid metabolism, and high intake of refined carbohydrates are linked to Alzheimer's disease Discusses how genetic makeup can impact risk of Alzheimer’s and Parkinson’s disease Examines cognitive changes in neurodegeneration, lists current tests for determining cognitive impairment, and provides information concerning differential diagnosis Discusses potential advantages of increasing antioxidant and micronutrient intake Reviews hormonal influences on neurodegeneration Examines the links between protein intake and Alzheimer’s disease. Neurodegeneration and Alzheimer's Disease is an essential resource for researchers, medical practitioners, dietitians, and students with an interest in neurological diseases and their diagnosis and risk factors, as well as diet-related conditions such as diabetes and obesity. Lifestyle and diet influence neurodegeneration risk, and a better understanding of this evidence amongst health professionals will hopefully lead to greater public awareness of how to reduce the likelihood of these widespread conditions.