Serum Interleukin 8 Concentrations in Obese Subjects With and Without Impaired Glucose Tolerance

Interleukin 8 (IL-8) is a cytokine with atherogenic properties. Studies revealed that it is produced and secreted by human adipocytes. The aim of the present study is to evaluate serum IL-8 concentrations in obese subjects with normal glucose tolerance (NGT) and in obese subjects with impaired glucose tolerance (IGT) in fasting state and after oral glucose tolerance test (OGTT) and to find any relation between serum IL-8 and BMI, WHR and glucose level. A total of 60 subjects with marked overweight or obesity (BMI 27.8kg/m^2), without previously diagnosed disturbances of glucose tolerance, were included in the present study. They were divided into two groups. Group I included 30 subjects with NGT (13 men and 17 women) and group 2 included 30 subjects with IGT (11 men and 19 women). 25 sex and age-matched healthy lean volunteers were included as control group. In the fasting state, there was no significant difference in fasting serum IL- 8 concentrations between group I and group II. However, fasting serum IL-8 level was significantly higher in both groups in relation to control lean group (p 0.05 and 0.05 respectively). After OGTT, serum IL-8 level showed no significant difference in lean group (p 0.05) and a highly significant increase in-group I and II (p 0.001). There was a highly significant increase in serum level of IL-8 after OGTT in-group I and II in relation to control group (p 0.01 and 0.001 respectively). There was also a highly significant increase in serum level of IL-8 in-group II when compared with group I (p 0.01). In both groups fasting serum IL-8 was related to BMI (group I, r=0.919, p 0.001; group 2, r=0.843, p 0.001), and also to WHR (group I, r=0.758, p 0.01; group II, r=0.641, p 0.05. There were no significant correlations between fasting serum IL-8 and plasma glucose level in studied groups. Serum IL-8 concentrations after OGTT were positively related to post load glucose level (r=0.83, p 0.001), in group II, but not in group I. We conclude that fasting serum IL-8 levels are increased in obese subjects with normal and impaired glucose tolerance, and are related to BMI and WHR. After OGTT, serum IL-8 levels are related to glucose level in obese subjects with IGT. It is possible that an increase in circulating serum IL-8 level might be one of the factors linking obesity and prediabetic stage with greater cardiovascular risk.