Evaluation of neurometabolic status with serum asprosin, leptin, ghrelin, amylin and zinc levels in obesity, Type 2 diabetes and alzheimer's disease (Type 3 diabetes)

Aim: Obesity and type 2 diabetes (T2DM) are associated with the development of Alzheimer's disease (AD), but the common molecular mechanism of insulin resistance is currently unknown. In our study; we aimed to examine the levels of asprosin, leptin and ghrelin in overweight/obese prediabetic, T2DM and AD patients, and to reveal the role and common aspects of these markers in energy homeostasis. Material and Method: Obese/overweight (Ob/Ow) volunteers, AD patients and healthy volunteer groups over the age of 40 classified according to the American Diabetes Association (ADA) were included in our study. Group1:Ob/Ow normal glucose tolerance(n=26), Group2:Ob/Ow isolated impaired fasting glucose(n=26), Group3:Ob/Ow impaired fasting glucose+impaired glucose tolerance(n=26), Group4:Ob /Ow T2DM(n=26), Group5:AD(n=26), Group6:Control (n=28). Biochemical analyzes were performed from venous blood samples. Comparisons between groups were made with One-way Anova (post-hoc Tukey) and Kruskal-Wallis (Mann-Whitney U), stratified analyzes and correlation analyzes with Pearson-Spearman tests in SPSS. Results: Asprosin levels were found to be statistically significantly higher in Alzheimer's (p<0.001) and T2DM (p=0.01) groups compared to the control group, regardless of age and body mass index (BMI). Asprosin levels were found to be positively correlated with age, 2nd hour glucose, HbA1c and creatinine levels. Compared to the control group; statistically significant leptin levels were found to be high in the first 4 groups, while statistically significant ghrelin levels were found to be low in group 1. Leptin was positively correlated with female gender, BMI, lipid profile, ALT, glucose, insulin, C-peptide, Homa-IR, and CRP levels, but no correlation was found with waist-hip ratio. It was determined that the leptin/ghrelin ratio decreased in ADA classification from group1 to group4. Conclusion: Asprosin is associated with glucose secretion rather than insulin resistance, and the decrease in leptin/ghrelin ratio deteriorates energy-glucose homeostasis; may be effective in the pathophysiology of T2DM in obesity. It has been determined for the first time in the literature that asprosin levels are higher in Alzheimer's disease regardless of age and BMI than in the control group. We think, it is appropriate to define Alzheimer's disease as type 3 diabetes because of its commonalities with T2DM and obesity. Keywords: Obesity, Alzheimer's disease, Type 2 Diabetes Mellitus