GSTT1 null genotype is a risk factor for diabetic retinopathy in Caucasians with type 2 diabetes, whereas GSTM1 null genotype might confer protection against retinopathy

Article type: Research Article

Authors: Cilenšek, Ines | Mankoč, Sara | Petrovič, Mojca Globočnik | Petrovič, Daniel

Affiliations: Institute of Histology and Embryology, Medical Faculty Ljubljana, University of Ljubljana, Ljubljana, Slovenia | Eye Clinic, University Medical Centre Ljubljana, Ljubljana, Slovenia

Note: [] Corresponding author: Danijel Petrovič, MD, PhD, Institute of Histology and Embryology, Medical Faculty of Ljubljana, Korytkova 2, 1105 Ljubljana, Slovenia. Tel.: +386 1 543 7367; Fax: +386 1 543 7361; E-mail: daniel.petrovic.@mf.uni-lj.si

Abstract: Aim: Substantial data indicate that oxidative stress is involved in the development of diabetic retinopathy (DR). The aim of the present study was to investigate whether the genetic polymorphisms: polymorphic deletions of glutathione S-transferases M1 (GSTM1) and T1 (GSTT1) and Ile105Val of the GSTP1 are associated with DR in Slovenian patients with type 2 diabetes. Methods: In this cross sectional case-control study 604 unrelated Slovene subjects (Caucasians) with type 2 diabetes mellitus were enrolled: 284 patients with DR (cases) and the control group of 320 subjects with type 2 diabetes of more than 10 years' duration who had no clinical signs of DR. Genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Results: In our study, the deletion of the GSTM1 was found less frequent in cases with DR than in the controls (27.5% versus 44.4%; P < 0.001), whereas the deletion of GSTT1 was found significantly more often in cases than in the controls (49.3% versus 29.7%; P < 0.001). We did not find statistically significant differences in the genotype distribution in GSTP1 (Ile105Val) polymorphism between cases and controls (40.5% versus 46.0%). Conclusions: We may conclude that individuals homozygous for the deletion of GSTT1 are at an ≈ 2-fold-greater risk of DR, whereas the GSTM1 deficiency is associated with lower frequency of DR in type 2 diabetics.

Keywords: Diabetes mellitus type 2, diabetic retinopathy, oxidative stress, glutathione S-transferase

DOI: 10.3233/DMA-2011-0863

Journal: Disease Markers, vol. 32, no. 2, pp. 93-99, 2012