Analysis of oxidative DNA damage and its repair in Polish patients with diabetes mellitus type 2: Role in pathogenesis of diabetic neuropathy

PurposeDistal symmetric polyneuropathy (DSPN) is common complication of type 2 diabetes (T2DM). In this work we investigated the role of oxidative damage in connection with particular polymorphisms of DNA repair genes and their repair capacity.Material/methodsMaterials constitute the peripheral blood of patients with T2DM with and without DSPN and control subjects without disturbance of the carbohydrate fraction. The study of gene polymorphisms which products take part in base excision repair (BER) pathway: 726 Val/Ala adenosine diphosphate ribosyl transferase (ADPRT), 324 His/Glu MutYhomolog (MUTYH) and 148 Asp/Glu human apurinic/apyrimidinic endonuclease (APE) was carried out using restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) method. The study of DNA damage induced by hydrogen peroxide and the efficiency of their repair was carried out using comet assay.ResultsNone of the 3 polymorphisms were associated with the risk of DSPN. However, in group of patients together with T2DM and T2DM/DSPN 726 Ala ADPRT allele was significantly susceptible to increased risk of T2DM (OR = 1.59; 95% CI: 1.08–2.36). Investigation of DNA damage and repair revealed that T2DM patients have decreased ability to DNA repair. This capacity even drops down in the group of T2DM/DSPN patients compared to subjects with diabetes alone. ADPRT and APE polymorphisms were significantly associated with higher DNA damages (P < 0.05) in heterozygous and mutant homozygous in correlation to homozygous wild type, but for MUTYH polymorphism relation was not confirmed.ConclusionsPathogenesis of T2DM and development of DSPN may be related to oxidative stress connected with BER gene polymorphisms.