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

Genetic variants of ALR (-106C → T /-12C → G) and serum PKC-δ are associated with peripheral neuropathy in Egyptian diabetic patients with impaired handwriting

Purpose

Diabetic peripheral neuropathy can injure the hand median nerve and cause extensive nerve damage. PKC and ALR are associated with progression of diabetic complications. We hypothesized a genetic association between the ALR polymorphisms (-106C → T/-12C → G) and elevated serum PKC-δ levels in diabetic neuropathy and its adverse effects on handwriting in Egyptian population.

Methods

One hundred DPN were compared with 100 DP and 100 healthy volunteers. ALR -106C → T/-12C → G variants were studied using the PCR-RFLP method. A routine set of standard laboratory markers was determined. Serum PKC-δ concentration was determined by ELISA. Logistic regression analysis and areas under the receiver characteristic curves (AUCs) were evaluated to investigate the predictors of diabetic neuropathy. Arabic handwriting was analyzed based on the recognition of functional features, word shape, and ascending/descending parts of letters.

Results

Individuals carrying ALR-106C → C and -12G → G had a significantly higher risk of developing diabetic neuropathy than individuals with -106C → T and -12C → G genotypes (P = 0.01, P = 0.02). Carriers of the (-106C → T) CC and (-12C → G) GG genotypes had significantly increased serum levels of PKC-δ, FBG, TC, and LDL-c. PKC- δ serum levels were significantly correlated with glycemic and lipid indicators (P < 0.001). PKC-δ is a significant predictor of diabetes with or without neuropathy at a cutoff value of 16.6, sensitivity was 89%, and specificity 100%. All DPN showed complete deterioration of handwriting after the onset of diabetic neuropathy.

Conclusion

The genetic variants ALR-106C → C / -12G → G and PKC-δ in serum may help in the detection and treatment of diabetic neuropathy in Egyptian population before writing performance is affected.

Aldose Reductase: a cause and a potential target for the treatment of diabetic complications

Diabetes mellitus, a disorder of metabolism, results in the elevation of glucose level in the blood. In this hyperglycaemic condition, aldose reductase overexpresses and leads to further complications of diabetes through the polyol pathway. Glucose metabolism-related disorders are the accumulation of sorbitol, overproduction of NADH and fructose, reduction in NAD⁺, and excessive NADPH usage, leading to diabetic pathogenesis and its complications such as retinopathy, neuropathy, and nephropathy. Accumulation of sorbitol results in the alteration of osmotic pressure and leads to osmotic stress. The overproduction of NADH causes an increase in reactive oxygen species production which leads to oxidative stress. The overproduction of fructose causes cell death and non-alcoholic fatty liver disease. Apart from these disorders, many other complications have also been discussed in the literature. Therefore, the article overviews the aldose reductase as the causative agent and a potential target for the treatment of diabetic complications. So, aldose reductase inhibitors have gained much importance worldwide right now. Several inhibitors, like derivatives of carboxylic acid, spirohydantoin, phenolic derivatives, etc. could prevent diabetic complications are discussed in this article.