Association between Interleukin-10 Gene (-1082g/A) Polymorphism and Type 2 Diabetes, Diabetes-Related Traits, and Microvascular Complications in the Croatian Population

SUMMARY – Interleukin (IL)-10 is an anti-inflammatory cytokine, and a decrease in its secretion is associated with obesity, metabolic syndrome and type 2 diabetes. However, it has not been established whether the intensity of the immune response during diabetes-associated chronic inflammation affects the development and/or progression of type 2 diabetes and its microvascular complications. The aim of this study was to investigate the role of single nucleotide polymorphism (SNP)-1082G/A for IL-10 gene in development of diabetes type 2 and its complications. DNA was extracted from blood cells of 240 overweight/obese subjects for IL-10 genotyping. Based on the presence of diabetes type 2, patients were divided in two groups: experimental group of 144 patients with diabetes type 2 and control group of 96 age- and gender-matched subjects without diabetes. Compared to control group, diabetic group had higher levels of leukocytes (p=0.012), fibrinogen (p=0.049) and plasminogen activator inhibitor-1 (PAI-1) (p=0.009), and lower levels of albumin (p=0.001). There were no differences in the frequency of SNP-1082G/A for IL-10 gene between the two groups (p=0.654). When considering diabetes related traits in all subjects in relation to specific genotype, a group with homozygous (AA) genotype had higher values of the mean fasting glucose (p<0.000001), HbA1c (p<0.000001) and HOMA-IR (p=0.003632), while the mean HOMA-B value (p=0.000178) was lower when compared to the groups with GG and GA genotypes. There was no difference in development of diabetic nephropathy, retinopathy and polyneuropathy between the IL-10 polymorphism genotypes. In conclusion, obese diabetes type 2 patients had an increased inflammation activity compared to obese non-diabetic individuals. There was no association of the investigated polymorphisms and development of type 2 diabetes and its microvascular complications. However, diabetes related traits clearly depended on the presence of specific IL-10 genotype.