Decreased serum brain-derived neurotrophic factor concentration in young nonobese subjects with low insulin sensitivity
Monika Karczewska-Kupczewska, Agnieszka Adamska, Agnieszka Nikolajuk, Elzbieta Otziomek, Maria Gorska, Marek Straczkowski & Irina Kowalska
Insulin resistance and type 2 diabetes are associated with an increased risk of neurodegenerative diseases. Brain-derived neurotrophic factor (BDNF) regulates neuronal differentiation and synaptic plasticity and its decreased levels are supposed to play a role in the pathogenesis of Alzheimer disease and other disorders. Decreased circulating BDNF levels in obesity and type 2 diabetes were reported, however, it is unclear, whether BDNF might be associated with insulin resistance in young, nonobese population.
The aim of the present study was to estimate serum BDNF concentration in apparently healthy, nonobese women divided into subgroups according to their insulin sensitivity.
We studied 46 young (age: 25.15±5.16 years), apparently healthy, nonobese (BMI: 24.02±2.84 kg/m2) women with normal glucose tolerance. Anthropometric and biochemical parameters and serum concentrations of BDNF and adiponectin were measured. Insulin sensitivity was estimated with the euglycemichyperinsulinemic clamp technique. Then, participants were divided into subgroups of high (high IS, above median from the clamp study, n=23) and low insulin sensitivity (low IS, below median, n=23).
The difference in BMI and waist circumference between the groups did not reach the level of significance, whereas the percent of body fat was higher in the low IS group (P=0.024). We observed decreased serum BDNF concentration in women with low IS (P=0.001), which remained significant after adjustment for the difference in the percent of body fat. In the entire study population, serum BDNF was positively related to insulin sensitivity (r=0.43, P=0.003). In multiple regression analysis, this correlation remained significant after adjustment for other estimated parameters. In the low IS group, relationship between serum BDNF and adiponectin was also observed (r=0.52, P=0.027).
Our data show that serum BDNF is decreased in young nonobese women with low IS. Thus, early detection and prevention of insulin resistance might be useful in the prevention of neurodegenerative disorders.