ENDO: Weight Loss May Lower Amyloid Precursor Protein
Reduced expression of APP mRNA, genes related to Alzheimer's disease following weight loss
MONDAY, June 6 (HealthDay News) -- There is a considerable decrease in amyloid precursor protein (APP) and APP mRNA, and in the expression of other genes related to Alzheimer's disease following weight loss after bariatric surgery, according to a study presented at ENDO 2011, the annual meeting of The Endocrine Society, held from June 4 to 7 in Boston.
Paresh Dandona, M.D., from the State University of New York at Buffalo, and colleagues investigated whether peripheral blood mononuclear cell (MNC) expression of APP diminishes after the pronounced caloric restriction and weight loss associated with Roux-en-Y gastric bypass surgery (RYGB). Fifteen patients with type 2 diabetes and morbid obesity underwent RYGB, and their weight, body mass index (BMI), blood glucose and insulin levels, and homeostasis model assessment-insulin resistance (HOMA-IR) were measured after six months. The expression of other genes related to Alzheimer's disease, including presenilin 2 (PN2), ADAM-9, and GSK-3, were also monitored.
The investigators found that the patients lost an average of 38.5 kg, and their BMI decreased from 54.4 to 40.5 kg/m². There was a significant decrease in the average plasma concentrations of glucose and insulin, and in HOMA-IR. The expression of both APP and APP mRNA decreased (31 and 22 percent, respectively). There was a significant decrease in PN2, ADAM-9, and GSK-3 (27, 35, and 28 percent, respectively). These changes occurred along with significant reductions in other pro-inflammatory mediators, including C-reactive protein.
"Obesity and caloric intake modulate the expression of APP in MNCs. If indeed this effect also occurs in the brain, this may have implications for the pathogenesis and the treatment of Alzheimer's disease," the authors write.