Association of aldose reductase gene polymorphism (C-106T) in susceptibility of diabetic peripheral neuropathy among north Indian population

Discovery of a Novel Benzothiadiazine-Based Selective Aldose Reductase Inhibitor as Potential Therapy for Diabetic Peripheral Neuropathy

Aldose reductase 2 (ALR2), an activated enzyme in the polyol pathway by hyperglycemia, has long been recognized as one of the most promising targets for complications of diabetes, especially in diabetic peripheral neuropathy (DPN). However, many of the ALR2 inhibitors have shown serious side effects due to poor selectivity over aldehyde reductase (ALR1). Herein, we describe the discovery of a series of benzothiadiazine acetic acid derivatives as potent and selective inhibitors against ALR2 and evaluation of their anti-DPN activities in vivo. Compound 15c, carrying a carbonyl group at the 3-position of the thiadiazine ring, showed high potent inhibition against ALR2 (IC50 = 33.19 nmol/L) and ∼16,109-fold selectivity for ALR2 over ALR1. Cytotoxicity assays ensured the primary biosafety of 15c. Further pharmacokinetic assay in rats indicated that 15c had a good pharmacokinetic feature (t1/2 = 5.60 h, area under the plasma concentration time curve [AUC(0-t)] = 598.57 ± 216.5 μg/mL * h), which was superior to epalrestat (t1/2 = 2.23 h, AUC[0-t] = 20.43 ± 3.7 μg/mL * h). Finally, in a streptozotocin-induced diabetic rat model, 15c significantly increased the nerve conduction velocities of impaired sensory and motor nerves, achieved potent inhibition of d-sorbitol production in the sciatic nerves, and significantly increased the paw withdrawal mechanical threshold. By combining the above investigations, we propose that 15c might represent a promising lead compound for the discovery of an antidiabetic peripheral neuropathy drug.

A Drosophila model of diabetic neuropathy reveals a role of proteasome activity in the glia

Diabetic peripheral neuropathy (DPN) is the most common chronic, progressive complication of diabetes mellitus. The main symptom is sensory loss; the molecular mechanisms are not fully understood. We found that Drosophila fed a high-sugar diet, which induces diabetes-like phenotypes, exhibit impairment of noxious heat avoidance. The impairment of heat avoidance was associated with shrinkage of the leg neurons expressing the Drosophila transient receptor potential channel Painless. Using a candidate genetic screening approach, we identified proteasome modulator 9 as one of the modulators of impairment of heat avoidance. We further showed that proteasome inhibition in the glia reversed the impairment of noxious heat avoidance, and heat-shock proteins and endolysosomal trafficking in the glia mediated the effect of proteasome inhibition. Our results establish Drosophila as a useful system for exploring molecular mechanisms of diet-induced peripheral neuropathy and propose that the glial proteasome is one of the candidate therapeutic targets for DPN.

Rationale and design of the Aldose Reductase Inhibition for Stabilization of Exercise Capacity in Heart Failure Trial (ARISE-HF) in patients with high-risk diabetic cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DbCM) is a specific form of heart muscle disease that may result in substantial morbidity and mortality in individuals with type 2 diabetes mellitus (T2DM). Hyperactivation of the polyol pathway is one of the primary mechanisms in the pathogenesis of diabetic complications, including development of DbCM. There is an unmet need for therapies targeting the underlying metabolic abnormalities that drive this form of Stage B heart failure (HF).

METHODS

Aldose reductase (AR) catalyzes the first and rate-limiting step in the polyol pathway, and AR inhibition has been shown to reduce diabetic complications, including DbCM in animal models and in patients with DbCM. Previous AR inhibitors (ARIs) were limited by poor specificity resulting in unacceptable tolerability and safety profile. AT-001 is a novel investigational highly specific ARI with higher binding affinity and greater selectivity than previously studied ARIs. ARISE-HF (NCT04083339) is an ongoing Phase 3 randomized, placebo-controlled, double blind, global clinical study to investigate the efficacy of AT-001 (1000 mg twice daily [BID] and 1500 mg BID) in 675 T2DM patients with DbCM at high risk of progression to overt HF. ARISE-HF assesses the ability of AT-001 to improve or prevent decline in exercise capacity as measured by functional capacity (changes in peak oxygen uptake [peak VO₂]) over 15 (and possibly 27) months of treatment. Additional endpoints include percentage of patients progressing to overt HF, health status metrics, echocardiographic measurements, and changes in cardiacbiomarkers.

RESULTS

The ARISE-HF Trial is fully enrolled.

CONCLUSIONS

This report describes the rationale and study design of ARISE-HF.

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.

PPARɣ2, aldose reductase, and TCF7L2 gene polymorphisms: relation to diabetes mellitus

Purpose

Diabetes mellitus (DM) is a growing global health concern. Genetic factors play a pivotal role in the development of diabetes. Therefore, the present work aimed to study the relation between peroxisome proliferator-activate receptors (PPARɣ2) (rs3856806), aldose reductase (AR) (rs759853), transcription factor 7 like 2 (TCF7L2) (rs7903146) gene polymorphism with diabetes in the Egyptian population.

Methods

The study included 260 diabetics and 120 healthy subjects. Genotyping was done using polymerase chain reaction-restriction fragment length polymorphism.

Results

Regression analysis revealed that PPARɣ2 TT, TCF7L2 TT were suggested to be independent risk predictors for T1DM and TCF7L2 TC, CC genotype were suggested to be independent protective factors against T1DM development. On the other hand, PPARɣ2 TT, AR TT genotypes were suggested to be independent risk predictors for T2DM susceptibility, and PPARɣ2 CT genotypes were suggested to be independent protective factors against T2DM development.

Conclusion

The present study revealed that PPARγ2 (rs3856806), TCF7L2 (rs7903146) and AR (rs759853) gene polymorphism may play an important role in the susceptibility of diabetes. Therefore, these polymorphisms may have a prognostic value for diabetes in the Egyptian population. Further work is required to confirm the role of these polymorphisms in diabetes.

Association between Aldose Reductase Gene C(-106)T Polymorphism and Diabetic Retinopathy: A Systematic Review and Meta-Analysis

Controversial results regarding the associations between aldose reductase (AR) genetic polymorphisms and diabetic retinopathy (DR) have been reported for many years. The present meta-analysis was performed to clarify the effects of the AR gene C(-106)T polymorphism on DR risk. The PubMed, Web of Sciences, Cochrane library, EMBASE, Chinese National Knowledge Infrastructure, and Wan Fang databases were extensively searched in Chinese to select relevant studies with an updated date of April 25, 2018. The Newcastle-Ottawa Scale (NOS) was applied to assess quality. The random-effects model was applied to calculate the pooled OR and 95% CI. This meta-analysis identified 23 studies with an average score of 7.52 for NOS analysis, including 4,313 DR cases and 5,128 diabetes mellitus (DM) control cases. In the overall analysis, a significant association between the AR gene C(-106)T polymorphism and DR susceptibility was found. In subgroups stratified by DM type and ethnicity, significantly increased risks for DR were found in DM type 1, East Asian populations, and Middle Eastern populations. Compared with DR control cases, the following associations were found: T vs. C: OR 0.91, 95% CI 0.85-0.97, I2 = 72.9%; CT + TT vs. CC: OR 0.75, 95% CI 0.68-0.81, I2 = 86.7%; and CT vs. CC: OR 0.86, 95% CI 0.78-0.94, I2 = 70.5%. The results of this meta-analysis showed a significant association between the AR gene C(-106)T polymorphism and susceptibility to DR in DM patients. DM patients with allele T and CT+TT genotype of the AR gene may have a lower risk of DR.

Meta-analysis of the association between aldose reductase gene (CA)n microsatellite variants and risk of diabetic retinopathy

Diabetic retinopathy (DR) is one of the most severe microvascular complications of diabetes mellitus (DM). The (CA)n microsatellite variation of the aldose reductase (ALR) gene has been indicated to be associated with DR in previous studies; however, the results were inconclusive. To provide a more precise evaluation of the association between the (CA)n variations of ALR and the risk for DR, a meta-analysis was performed in the present study. Relevant articles were retrieved from the PubMed, Embase, Chinese National Knowledge Infrastructure and Cochrane Library databases. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the strength of the associations. The present meta-analysis included 17 studies comprising 1,575 DM patients with retinopathy and 1,741 DM patients without retinopathy. The results indicated that the Z-2 allele was a risk factor for DR in Asian (OR=1.82, 95% CI: 1.16-2.86, P=0.009) and Caucasian (OR=2.08, 95% CI: 1.14-3.79, P=0.02) populations, as well as in type 1 diabetes (T1D; OR=3.42, 95% CI: 1.46-8.04, P=0.005) and type 2 diabetes (T2D; OR=1.66, 95% CI: 1.05-2.63, P=0.03). Furthermore, the Z+2 allele was determined to be a protective factor for DR in Caucasian individuals (OR=0.50, 95% CI: 0.34-0.73, P=0.0004) and those with T1D (OR=0.39, 95% CI: 0.27-0.57, P<0.00001). Z+4 was also identified to be a protective factor, reducing the risk of DR in patients with T1D (OR=0.74, 95% CI: 0.57-0.96, P=0.02). Z-4 was revealed to be a risk factor for DR in Asian populations (OR=1.57, 95% CI: 1.22-2.03, P=0.0005) and in individuals with T1D (OR=1.62, 95% CI: 1.27-2.08, P=0.0001). However, no association was detected between the Z, Z+6 and Z-6 alleles and the risk of DR (P>0.05). In conclusion, the present results revealed the following: Z+2 may serve as a protective factor for DR in Caucasian individuals and those with T1D; Z+4 may be a protective factor for DR in patients with T2D; Z-2 may represent a risk factor for DR in all subgroups analyzed; and Z-4 may be a risk factor for DR in Asian populations and patients with T2D.

Genetics of diabetic neuropathy: Systematic review, meta-analysis and trial sequential analysis

OBJECTIVE

Diabetic neuropathy (DN) is one of the most common complications of diabetes that occurs in more than 67% of individuals with diabetes. Genetic polymorphisms may play an important role in DN development. However, until now, the association between genetic polymorphisms and DN risk has remained unknown. We performed a systematic review, meta-analysis, and trial sequential analysis (TSA) of the association between all genetic polymorphisms and DN risk.

METHODS

Relevant published studies examining the relationship between all genetic polymorphisms and DN were obtained based on a designed search strategy up to 28 February 2019. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess overall pooled effects of genetic models as well as in subgroup analyses. Sensitive analysis and publication bias were applied to evaluate the reliability of the study. Moreover, TSA was conducted to estimate the robustness of the results.

RESULTS

We conducted a systematic review of a total of 1256 articles, and then 106 publications reporting on 136 polymorphisms of 76 genes were extracted. We performed 107 meta-analyses on 36 studies involving 12,221 subjects to derive pooled effect estimates for eight polymorphisms. We identified that ACE I>D, MTHFR 1298A/C, GPx-1 rs1050450, and CAT -262C/T were associated with DN, while MTHFR C677T, GSTM1, GSTT1, and IL-10 -1082G/A were not. Sensitivity analysis, funnel plot, and Egger's test displayed robust results. Furthermore, the results of TSA indicated sufficient sample size in studies of ACE, GPx-1, GSTM1, and IL-10 polymorphisms.

INTERPRETATION

Our study assessed the association between ACE I>D, MTHFR C677T, MTHFR 1298A/C, GPx-1 rs1050450, CAT -262C/T, GSTM1, GSTT1, and IL-10 -1082G/A polymorphisms and DN risk. We hope that the data in our research study are used to study DN genetics.