Molecular Insights into Appetite Control and Neuroendocrine Disease as Risk Factors for Chronic Diseases in Western Countries

Environmental factors such as stress, anxiety and depression are important to consider with the global increase in chronic diseases such as cardiovascular diseases, cancer, stroke, obesity, diabetes and neurodegenerative diseases. Brain metabolic diseases associated with conditions such as obesity and diabetes require early intervention with diet, lifestyle and drug therapy to prevent diseases to various organs such as the liver with non alcoholic fatty liver disease (NAFLD) and other organs such as the heart, lungs thyroid, pancreas, brain, kidneys and reproductive systems. Behavioural stress and the molecular mechanisms that are involved in neuroendocrine diseases such as insulin resistance in obesity require attention since associated inflammatory processes early in the disease process have been associated with neurodegenerative diseases. Molecular neuroendocrine disturbances that cause appetite dysregulation and hyperphagia are closely linked to hyperinsulinemia, dyslipidaemia and reduced lifespan. The origins of metabolic diseases that afflict various organs possibly arise from hypothalamic disturbances with loss of control of peripheral endocrine hormones and neuropeptides released from the brain. Diet and drug therapies that are directed to the autonomic nervous system, neuroendocrine and limbic systems may help regulate and integrate leptin and insulin signals involving various neuropeptides associated with chronic diseases such as obesity and diabetes. The understanding of brain circuits and stabilization of neuroanatomical structures in the brain is currently under investigation. Research that is involved in the understanding of diet and drugs in the stabilization of brain structures such as frontostriatal limbic circuits, hypothalamus brainstem circuits and parasympathetic nervous system is required. Information related to neuropeptides and neurotransmitters that are released from the brain and their regulation by therapeutic drugs requires further assessment. The promise of appropriate diets, lifestyle and drugs that target the CNS and peripheral tissues such as the adipose tissue, liver and pancreas may improve the prognosis of chronic diseases such as obesity and diabetes that are also closely associated with neurodegeneration

Diet and nutrition reverse Type 3 diabetes and accelerated aging linked to global chronic diseases

The acceleration in the rate of chronic diseases that involve insulin resistance has become of global concern. The rate of the most prevalent chronic disease such as cardiovascular disease is linked to the metabolic syndrome, non alcoholic fatty liver disease (NAFLD) and other chronic diseases that include obesity, diabetes and neurodegenerative diseases. The gene-environment interaction in Western countries indicates that with urbanization access to food and its content may lead to induction of epigenetic alterations and identify the gene Sirtuin 1 (Sirt 1) to be responsible for the increased risk for insulin resistance and NAFLD relevant to Type 1, Type 2 and Type 3 diabetes in these countries. Nutrigenomics is linked to neuron and liver telomere maintenance, cell division and tissue growth and has become important with essential nutrients that regulate Sirt 1 function important to prevent NAFLD in individuals with diabetes. Nutrigenomic diets, exercise, drugs and lifestyle changes regulate Type 3 diabetes with neuron Sirt 1 transcriptional responses associated with DNA modifications that regulate brain insulin resistance relevant to NAFLD and diabetes

The Global Obesity Epidemic is Related to Stroke, Dementia and Alzheimer\u27s Disease

The global epidemic in obesity and diabetes has affected individuals in both the developing and developed world with the global death rate (63%) related to chronic diseases with 35% attributed to cardiovascular disease and stroke, 21 % to cancer and 12 % to chronic respiratory disease. The interest in connections between the global stroke epidemic, dementia and Alzheimer’s disease (AD) has increased with hypertension, smoking, diabetes, obesity, poor diet, physical inactivity, atrial fibrillation, excessive alcohol consumption, abnormal lipid profile and psychosocial stress/depression implicated in their pathogenesis. The connection between stroke and AD is possibly related to the low adiponectin and high density lipoprotein (HDL) cholesterol levels that are found in hypertensive, obese, diabetic and AD individuals. In obesity adipocyte dysfunction may be related to the down regulation of the AD gene Sirtuin 1, overexpression of the amyloid precursor protein (APP) and mitochondrial apoptosis with relevance to the renin-angiotensin system (RAS) that is associated with accelerated aging, NAFLD, stroke and AD. The unresolved finding of low plasma HDL and adiponectin in the metabolic syndrome may involve the stress hormone angiotensin II (Ang II) with vascular disturbances. Increased levels of adipocyte Ang II are possibly linked to the low plasma HDL contents in stroke and AD individuals. In obese and diabetic individuals the release of stress factors and diet control the activation of the RAS with increased levels of Ang II that are possibly implicated in the dyslipidemia associated with hypertension, cardiovascular disease, stroke and AD related dementia

Increased Risk for Obesity and Diabetes with Neurodegeneration in Developing Countries

The incidence of global obesity and Type 2 diabetes has increased and is predicted to rise to 30% of the global population. Diet and lifestyle factors are incapable to resolve the increased incidence for obesity and diabetes in various populations of the world. Developing countries have come to the forefront because of the higher diabetic epidemic. The urbanization may possibly provide an explanation for the global diabetic epidemic. In Western countries the metabolic syndrome and non alcoholic fatty liver disease (NAFLD) have reached 30 % of the population and now at present NAFLD afflicts 20% of developing populations. Western diets and sedentary lifestyles cause metabolic disorders in developing countries which may increase neurodegenerative diseases by the disrupted metabolism of xenobiotics in urban populations. In developing countries access to high calorie diets in urban areas down regulate liver nuclear receptors that are responsible for glucose, lipid and toxicological sensing and interrupt the metabolism of xenobiotics that become toxic to various tissues such as the pancreas, heart, kidney, brain and liver. Xenobiotics in urban areas induce epigenetic changes that involve chromatin remodelling by alterations in transcriptional regulators with modification of histones. Dysfunction of nuclear receptors such as the calorie sensitive sirtuin 1 (Sirt 1) gene involves abnormal nutrient metabolism with insulin resistance, NAFLD, energy balance and circadian rhythm disorders. In obesity and diabetes insulin resistance has been connected to poor xenobiotic metabolism with the toxic affects of increased xenobiotic transport to the brain associated with neurodegeneration. Dietary interventions to increase xenobiotic metabolism are likely to reduce oxidative stress and neuroendocrine disease in developing countries. Prevention programs are an important goal of international health organizations and in developing countries the plans to adapt a healthy diet, active lifestyle and reduced exposure to xenobiotics are important to manage the global epidemic for obesity and diabetes

Increased risk for obesity and diabetes with neurodegeneration in developing countries

The incidence of global obesity and Type 2 diabetes has increased and is predicted to rise to 30% of the global population. Diet and lifestyle factors are incapable to resolve the increased incidence for obesity and diabetes in various populations of the world. Developing countries have come to the forefront because of the higher diabetic epidemic. The urbanization may possibly provide an explanation for the global diabetic epidemic. In Western countries the metabolic syndrome and non alcoholic fatty liver disease (NAFLD) have reached 30 % of the population and now at present NAFLD afflicts 20% of developing populations. Western diets and sedentary lifestyles cause metabolic disorders in developing countries which may increase neurodegenerative diseases by the disrupted metabolism of xenobiotics in urban populations. In developing countries access to high calorie diets in urban areas down regulate liver nuclear receptors that are responsible for glucose, lipid and toxicological sensing and interrupt the metabolism of xenobiotics that become toxic to various tissues such as the pancreas, heart, kidney, brain and liver. Xenobiotics in urban areas induce epigenetic changes that involve chromatin remodelling by alterations in transcriptional regulators with modification of histones. Dysfunction of nuclear receptors such as the calorie sensitive sirtuin 1 (Sirt 1) gene involves abnormal nutrient metabolism with insulin resistance, NAFLD, energy balance and circadian rhythm disorders. In obesity and diabetes insulin resistance has been connected to poor xenobiotic metabolism with the toxic affects of increased xenobiotic transport to the brain associated with neurodegeneration. Dietary interventions to increase xenobiotic metabolism are likely to reduce oxidative stress and neuroendocrine disease in developing countries. Prevention programs are an important goal of international health organizations and in developing countries the plans to adapt a healthy diet, active lifestyle and reduced exposure to xenobiotics are important to manage the global epidemic for obesity and diabetes

Identification of plasma lipid biomarkers in Alzheimer\u27s disease

Alzheimer’s disease (AD), the commonest form of dementia, is a chronic, progressive neurodegenerative disease which manifests clinically as a slow global decline in cognitive function, including deterioration of memory, reasoning, abstraction, language and emotional stability, culminating in a patient with end-stage disease, totally dependent on custodial care. With an ageing population, there is predicted to be a marked increase in the number of people diagnosed with AD in the coming decades, making this a significant challenge to socio-economic policy and aged care. Currently there is no cure for AD and while current therapies may temporarily ameliorate symptoms, death usually occurs approximately 8 years after diagnosis. Attention is now being directed to the discovery of biomarkers that may not only facilitate pre-symptomatic diagnosis but provide an insight into aberrant biochemical pathways that may reveal potential therapeutic targets. AD pathogenesis develops over many years before clinical symptoms appear, providing the opportunity to develop therapy that could slow or stop disease progression well before any clinical manifestations develop. Research and understanding of AD pathology has been driven in recent years by advances in technologies, enabling the precise investigation of the lipidome; the repertoire of lipid species present in cells and tissues that reflect the net effect of gene and protein expression, which in turn are influenced by the cellular environment. Lipidomic studies have identified abnormal lipid metabolism as a key component of the pathological processes which lead to the development of AD. Therefore, lipidomic studies are crucial for advancing the understanding of AD pathology and for identifying potential therapeutic targets; these studies may also facilitate biomarker discovery. Many studies have reported abnormal lipid profiles in both AD plasma and brain tissue. This thesis investigated plasma lipid species using a “shotgun” lipidomics approach by electrospray ionisation tandem mass spectrometry (ESI/MS/MS). Additionally, Phospholipid Transfer Protein (PLTP); a protein involved in lipid metabolism was assayed using a commercial kit. The utility of these analytes as potential AD biomarkers was investigated by testing plasma samples from the highly characterised Australian Imaging, Biomarkers and Lifestyle (AIBL) study. The study cohort comprised over 1000 participants at inception who were classified as either healthy control (n=733), mild cognitive impairment (MCI, n=125) or AD (n=204): Samples from the baseline and 18 month follow-up time points were utilised. Plasma PLTP activity levels were measured in a subset of the baseline samples (n=259). Lipid and PLTP measurements were analysed in conjunction with supplementary neuroimaging and blood biomarker data collected as part of the AIBL study. The thesis identified significant differences in several plasma lipids between clinical classification groups, including several ceramide, sphingomyelin (SM), phosphatidylethanolamine (PE), phosphatidylcholine (PC) and plasmalogen species. Additionally, a panel of lipids was identified which could distinguish AD participants from healthy controls with a sensitivity and specificity of 80%. Plasma PLTP activity was significantly lower in AD and MCI groups compared to healthy controls, and levels correlated with plasma Aβ in all groups and cerebral Aβ in the healthy controls. The results of this thesis validate and extend previous findings reported in the literature. The current findings provide evidence to indicate that several lipid species and PLTP show promise as potential blood biomarkers of AD. Further investigation using a targeted lipidomics platform and prospective longitudinal follow-up is warranted