Relationship Of Metabolism-related Factors And Alzheimer’s Disease

Background:Alzheimer’s disease (AD) is a degeneration of central nervous system, characterized by progressive decline in cognitive, decrease in daily living and may be associated with various psychiatric symptoms and behavior disorders.The incidence rate of the disease has been rising since German neuropathologist, Alois Alzheimer, reported for the first time in1907.In recent years, with the increase of aging population,the incidence of Alzheimer’s disease is gradual high in China. Though the pathogenesis of Alzheimer’s disease is not yet totally clear, metabolic disorders may play an important role in the development of Alzheimer’s disease. There may be many complicated potential mechanisms which make abnormal glucose metabolism lead to AD, including direct toxicity caused by high blood glucose, short energy supply in brain because of low blood sugar, insulin resistance, abnormalities of insulin signal transduction or insulin degrading enzyme gene, and so on. Leptin is secreted by adipose tissue which was discovered in1994, it is closely related to glucose metabolism disorders, obesity, and so on.It was found that leptin may be the protective factor in the course of Alzheimer’s disease in recent years. Therefore, it helps us to understand the pathogenesis of AD by exploring the association between the metabolism-related factors (insulin, insulin-degrading enzyme and leptin) and Alzheimer’s disease, in order to find new potential avenues for prevention and treatment of Alzheimer’s disease.PART ONEAnalysis of plasma fasting glucose, fasting insulin and insulin degrading enzyme levels in Alzheimer’s diseaseObjective:To explore the association between diabetes-related factors(fasting glucose, fasting insulin and insulin degrading enzyme) and Alzheimer’s disease (AD).Methods:32patients with AD(the patient group) and30normal elderly subjects (the control group) were enrolled. The two groups were all tested by Mini-mental state examination(MMSE) and the patient group was divided into the mild, medium and severe groups with Clinical dementia rating(CDR).Blood samples were used for determining serum fasting insulin(Fins) by chemiluminescence assay and insulin degrading enzyme(IDE) by enzyme linked immunosorbent assay.Results:1. There were no significant differences between the experimental group and the control group in height, weight, BMI, fasting blood glucose, total cholesterol, triglyceride concentration, low density lipoprotein cholesterol, high density lipoprotein cholesterol, insulin and insulin resistance index (P>0.05).2. The serum IDE in the patient group was declined compared with the control group (P<0.05)3. There was a positive correlation of fasting glucose (FPG) and Fins with IDE in the control group while no correlation in the patient group.4. The score of MMSE was negatively correlated with the level of FPG in the patient group.5. There were no differences among the patients in different stages.Conclusion:IDE level decreased in patients with AD and may influence the function of IDE to adjust the insulin and the insulin resistance. IDE may play a role in AD. PART TWO Analysis of leptin levels and the relationship between leptin and diabetes-related factors in Alzheimer’s diseaseObjective:To explore the association between leptin and Alzheimer’s disease (AD) and the relationship between leptin and diabetes-related factors(fasting glucose, fasting insulin and insulin resistance) in AD.Methods:32patients with AD (the patient group) and30normal elderly subjects (the control group) were enrolled. The two groups were all tested by mini-mental state examination (MMSE) and the patient group was divided into the mild, medium and severe groups with clinical dementia rating (CDR). Blood samples were used for determining serum fasting insulin (Fins) by chemiluminescence assay and leptin by enzyme linked immunosorbent assay.Results:1. There were no significant differences between the experimental group and the control group in insulin and insulin resistance index (P>0.05).2. The serum leptin in the patient group was declined compared with the control group (P<0.05)3. There was a positive correlation of Fins and insulin resistance with leptin in the control group while no correlation in the patient group.4. There were no differences among the patients in different stages.Conclusion:Leptin level decreased in patients with AD and may influence the function of leptin to adjust the insulin and the insulin resistance. Leptin may play a role in AD.