Investigation of the relationship between HİF-1 alpha and VEGF levels and body mass index in obese individuals

Objective: In the present study, we aimed to investigate the importance of plasma HIF-1α and VEGF levels in the pathogenesis of obesity and the relationship between these molecules and BMI, body fat percentage and waist/hip ratios in obese individuals. Materials and Methods: 45 obese individuals and 28 healthy controls with normal weight were included in our study. Nineteen of 45 obese individuals had at least one accompanying metabolic disease. After 12 hours of fasting body mass index (BMI), body fat percentage and waist/hip ratio measurements were performed with a bioelectrical impedance analyzer from the individuals participating in the study. Microelisa method was used for the measurement of plasma HIF-1α and VEGF levels. Results: HIF-1α plasma levels were found to be 2.78 ± 0.46 ng/mL in obese individuals and 1.37 ± 0.04 ng/mL in the control group, the difference was statistically significant (p=0.0192), VEGF plasma levels were also found in obese individuals (1396 ± 250 ng/l) was significantly higher than the control group (594.90 ± 15.65 ng/l, p=0.0141). BMI, body fat percentage and waist/hip ratio were significantly higher in obese individuals compared to the controls (p<0.05 for all). A strong positive correlation was found between HIF-1α and VEGF levels in obese individuals (r=0.966, p=0.0001). Again, significant positive correlations were found between body fat percentage and BMI, and between body fat percentage and waist/hip ratio in obese individuals (r=0.383, p=0.009 and r=0.617, p=0.0001, respectively). A significant increase was observed in age (years) and body fat percentage in obese individuals with metabolic disease compared to those without metabolic desease (p=0.0006 and p=0.0083, respectively). However there was no difference in other parameters between obese individuals with and without metabolic disease (p>0.05 for all). Discussion: High plasma HIF-1α and VEGF levels in our study may indicate the role of hypoxia in the development of obesity and the importance of HIF-1α and VEGF in the pathogenesis of obesity. The strong correlation between plasma HIF-1α and VEGF levels in obese individuals suggests that the transcription factor HIF-1α, which is expressed in adipose tissue in response to hypoxia, provides VEGF expression by stimulating the VEGF promoter, and these proteins produced in adipose tissue pass into the circulation and their levels increase in the blood. There is no consensus in the literature regarding the relationship between VEGF or HIF-1α levels and BMI. In our study, no relationship was found between plasma VEGF levels and BMI in obese individuals. When our results and literature findings are examined, it is seen that studies to determine the relationship between VEGF and BMI should be conducted in a larger population due to the insufficient number of individuals included in the studies. In our study, the fact that obese individuals with metabolic disease have higher age (years) and body fat percentages than obese individuals without the disease show that the increase in age and body fat percentage may increase the risk of metabolic diseases in obesity. On the other hand, finding that plasma HIF-1α or VEGF levels are not different between obese individuals with at least one accompanying metabolic disease and obese individuals without the disease may reflect that elevated HIF-1α and VEGF levels are not risk factors for the development of metabolic diseases in obese individuals. Keywords: Obesity, Hypoxia, HIF-1α, VEGF, Body mass index