Enzyme activity and genetic polymorphisms in patients with type II diabetes mellitus

Diabetes mellitus (DM) has become more and more common and has a high morbidity and mortality rate worldwide. It is a multifactorial chronic disease affected by both genetic and environmental factors.

To evaluate the association between antioxidant enzyme activities and their genetic variations and the level of malondialdehyde (MDA) in type II diabetes patients living in the Adıyaman province in the southeast part of Turkey.

One hundred patients diagnosed with type II DM (T2DM) and 100 healthy controls were included in the study. Malondialdehyde levels and antioxidant enzyme activities were measured spectrophometrically. DNA isolation was performed and genotyping was carried out using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Our results revealed no significant differences in genotype distributions and allele frequencies of all polymorphisms between groups (p > 0.05). Significantly elevated MDA levels and a significant reduction in catalase (CAT) and paraoxonase (PON) enzyme activities were observed in patients compared to the control group in terms of study groups and genetic variations (p < 0.05). Moreover, CAT activity was reduced in TT genotype in terms of CAT -262 C/T polymorphism in patients (p < 0.05). Paraoxonase activity was observed to be lower in MM genotype in both groups (p < 0.05).

CAT -262 C/T polymorphism may be one of the factors that lead to severe clinical situation in DM. Our results suggest that TT genotype may be more prone to lipid peroxidation.