Evaluation of glutathione S-transferase polymorphism in Iranian patients with type 2 diabetic microangiopathy

Background

Overproduction of reactive oxygen species as a result of hyperglycemia in diabetes mellitus leads to microvascular complications. Glutathione S-transferases play important detoxifying roles with antioxidant potentials. This study aimed to assess whether the glutathione S-transferase M1 and T1 genotypes were associated with type 2 diabetes mellitus microangiopathic complications in the Iranian population.

Results

In this case-control study, the frequencies of null GSTM1 and GSTT1 genotypes were 4/72 (5.56%) and 12/72 (16.67%) respectively, in uncomplicated DM group. The frequencies of null GSTM1 and GSTT1 genotype in complicated DM group were 16/134 (11.94%) and 37/134 (27.61%), respectively. The proportion of GSTM1 null genotypes was higher in diabetic nephropathy compared to non-nephropathy (19.3% vs. 6.04 %, P = 0.006). At GSTT1 locus, patients with diabetic peripheral neuropathy had a higher frequency of deletion compared to those of without neuropathy (30.39% vs. 23.49%) (P = 0.02).

Conclusion

Selective polymorphisms encoding GSTM1 and GSTT1genes may prove useful as genetic markers to recognize individuals with an increased trend in developing diabetic nephropathy and neuropathy, respectively. This will help better identify individuals at higher risk toward microvascular complications of type 2 diabetes due to genetic susceptibility.

Aldose reductase (AC)n gene polymorphism in Iranian patients with type 2 diabetic microangiopathy; a case-control study

Aim

(AC)n promoter region of the aldose reductase (ALR) genes polymorphism has been associated with diabetic microvascular complications (MVCs). The aim of this study was to find the relationship between dinucleotide repeat (AC)n polymorphisms of the ALR gene and the occurrence of MVCs, such as diabetic retinopathy, neuropathy, and nephropathy in Iranian type 2 diabetic (T2D) patients.

Methods

This prospective case-control study was performed on T2D patients who were categorized into two groups based on the presence or absence of diabetic microangiopathy. All patients were provided informed consent. After extracting genomic DNA, the (AC)n of the ALR gene was determined using Polymerase chain reaction (PCR).

Results

Thirteen alleles of the (AC)n gene polymorphism were detected including Z + 16, Z + 14, Z + 8, Z + 6, Z + 4, Z + 2, Z, Z - 2, Z - 4, Z - 6, Z - 8, Z - 10, and Z - 12. The frequency of the Z - 4 allele was significantly higher in patients with retinopathy, nephropathy, and autonomic neuropathy compared with those with long-term uncomplicated diabetes (P < 0.001, P < 0.001, P = 0.031, respectively). After controlling for baseline risk factors, we found that the carrier of the Z - 4 allele of ALR (AC)n polymorphism had a higher risk of diabetic retinopathy and diabetic nephropathy (P < 0.001). The homozygosity for the Z - 4 allele was found to be associated with diabetic microangiopathy.

Conclusion

Our results showed that ALR (AC)n gene polymorphism in Iranian patients with type 2 diabetes independently, predispose retinal, renal and neural microvascular to diabetic complications.

Ocular abnormalities in multi-transfused beta-thalassemia patients

AIMS

The aim of this study was to assess ocular changes in thalassemia patients who have received multiple transfusions and chelate binding therapy in order to avoid iron accumulation.

SETTINGS AND DESIGN

A cross-sectional study.

SUBJECTS AND METHODS

A total of 54 thalassemia major patients were selected as case group, and 54 age- and sex-matched healthy subjects were regarded as a control group. Ocular examination included visual acuity, refraction testing, slit lamp examination, funduscopy, tonometry, perimetry, tear break-up time test, and color vision testing were performed for all the participants. We computed the frequency and duration of blood transfusion, the mean serum ferritin level, pretransfusion hemoglobin concentration, and type, duration, and daily dose of chelation therapy for thalassemia patients based on their records.

STATISTICAL ANALYSIS USED

All data analysis was performed using SPSS, version 19.

RESULTS

All the thalassemic patients were asymptomatic, but abnormal ocular findings (dry eye (33.3%), cataract (10.2%), retinal pigment epithelium degeneration (16.7%), color vision deficiency (3.7%), and visual field defects (33.7%)) were seen in 68.5% of thalassemic group. The prevalence of ocular abnormalities in normal group was 19.4%, which was significantly lower than that in thalassemia patients (P = 0.000). No significant correlation was found between ocular abnormalities and mean serum ferritin level (P = 0.627) and mean hemoglobin concentration (P = 0.143). Correlation of number of blood transfusion with the presence of ocular abnormalities was found to be statistically significant (P = 0.005).

CONCLUSIONS

As life expectancy for beta-thalassemia patients extends, regular ophthalmological evaluation to detect early changes in their ocular system is recommended.

Aldose reductase C-106T gene polymorphism in type 2 diabetics with microangiopathy in Iranian individuals

BACKGROUND

Aldose reductase (AR) is the rate-limiting enzyme in the glucose metabolism, which has been implicated in the pathogenesis of diabetic microvascular complications (MVCs). Frequent C-106T polymorphism in the promoter of the AR gene may change the expression of the gene.

AIMS

The aim of the following study is to study the association between AR C106T genotypes and diabetic MVCs in Iranian population.

MATERIALS AND METHODS

We included 206 type 2 diabetic patients categorized into two groups according to the presence or absence of diabetic microangiopathy. The cases of interest were diabetic neuropathy, retinopathy and nephropathy identified during clinical and or laboratory examination. In addition, 114 age- and sex-matched individuals were selected to serve as a control group. AR genotyping was done using an amplification gel electrophoresis.

RESULTS

The frequency of CC genotype was specifically higher in subjects with diabetic retinopathy as compared to those without it (53.2% vs. 38.1%, P = 0.030). Patients with diabetic microangiopathy in general; however, did not differ significantly between AR genotype groups.

CONCLUSION

The C-106T polymorphism in the AR gene is likely a risk factor for development of only retinal complication of diabetes microvascular in Iranian individuals.