Renin-Angiotensin-Aldosterone System Gene Polymorphisms and Type 2 Diabetic Nephropathy in Asian Populations: An Updated Meta-analysis

Distribution of the ACE Gene Polymorphisms in Type 2 Diabetes Mellitus Patients, Their Associations with Nephropathy Biomarkers and Metabolic Indicators at a Tertiary Hospital in Uganda

Purpose

We aimed at determining the distribution of the ACE insertion/deletion gene polymorphisms among type 2 diabetic patients and their association with the nephropathy biomarkers and the metabolic indicators.

Patients and Methods

Data were collected from 237 adult type 2 diabetes mellitus patients receiving healthcare at the diabetic clinic of Mbarara Regional Referral Hospital. Peripheral blood genomic DNA was amplified using a conventional PCR technique and analyzed for the ACE homozygous forms of the insertion (II), deletion (DD) and heterozygous insertion deletion (ID) genotypes as well as their respective allele counts. Biomarkers of nephropathy were analyzed on a Beckman coulter AU480 chemistry analyzer using system compatible reagents.

Results

Majority of the participants were older persons (Median = 57, IQR = 49-64) and female 171 (72.2%). Most of them had the Deletion allele 198 (83.5%) and DD genotype 116 (48.9%). At multivariate logistic regression, the nephropathy biomarkers that is microalbuminuria, serum creatinine, urea, eGFR and electrolytes had no association with the ACE I/D alleles or genotypes (p > 0.05). On the other hand, selected metabolic indicators had a positive relationship. The insertion allele was associated with increasing glycated hemoglobin (OR = 1.082, p = 0.019) and decreasing serum glucose levels (OR = 0.891, p = 0.001). Deletion allele was associated with decreasing glycated hemoglobin (OR = 0.924, p = 0.047) and increasing serum glucose levels (OR = 1.208, p = 0.001). ACE II genotype was associated with decreasing serum glucose levels (OR = 0.873, p = 0.029). ACE DD genotype was associated with decreasing glycated hemoglobin (OR = 0.917, p = 0.010) and increasing serum glucose levels (OR = 1.132, p = 0.001). ACE ID genotype was associated with increasing glycated hemoglobin (OR = 1.077, p = 0.022), triglyceride levels (OR = 1.316, p = 0.031) and decreasing serum glucose levels (OR = 0.933, p = 0.038).

Conclusion

The presence or absence of the ACE I/D alleles and genotypes affects the ultimate increase or decrease in the serum glucose, glycated hemoglobin and triglyceride levels. Although there was no significant association between the biomarkers of nephropathy and the ACE I/D alleles or genotypes, the above implicated metabolic indicators should be included in healthcare guidelines used when attending to type 2 diabetic patients.

Cardiorenal Outcomes with Finerenone in Asian Patients with Chronic Kidney Disease and Type 2 Diabetes: A FIDELIO-DKD post hoc Analysis

INTRODUCTION

In FIDELIO-DKD, finerenone significantly improved cardiorenal outcomes in patients with chronic kidney disease and type 2 diabetes (T2D). This post hoc analysis explores finerenone in patients from the Asian region.

METHODS

In FIDELIO-DKD, 5,674 patients with T2D and urine albumin-to-creatinine ratio (UACR) ≥30-<300 mg/g and estimated glomerular filtration rate (eGFR) ≥25-<60 mL/min/1.73 m2 or UACR ≥300-≤5,000 mg/g and eGFR ≥25-<75 mL/min/1.73 m2, treated with optimized renin-angiotensin system blockade, were randomized 1:1 to finerenone or placebo. Efficacy outcomes included a primary kidney composite (time to kidney failure, sustained decrease of ≥40% in eGFR from baseline, and death from renal causes) and secondary cardiovascular (CV) (time to CV death, non-fatal myocardial infarction, non-fatal stroke, or hospitalization for heart failure) and kidney (time to kidney failure, sustained decrease of ≥57% in eGFR from baseline, and death from renal causes) composites.

RESULTS

Of 1,327 patients in the Asian subgroup, 665 received finerenone. Finerenone reduced the ≥40% and ≥57% eGFR kidney and CV composite outcomes versus placebo in the Asian subgroup (hazard ratio [HR]: 0.70; 95% confidence interval [CI]: 0.56-0.87, HR: 0.73; 95% CI: 0.55-0.97, and HR: 0.85; 95% CI: 0.59-1.21, respectively), with no apparent differences versus patients from the rest of the world (HR: 0.88; 95% CI: 0.77-1.02; p interaction 0.09, HR: 0.78; 95% CI: 0.64-0.95; p interaction 0.71, and HR: 0.86; 95% CI: 0.74-1.00; p interaction 0.95, respectively). The safety profile of finerenone was similar across subgroups.

CONCLUSION

Finerenone produces similar cardiorenal benefits in Asian and non-Asian patients.

The Predisposition for Type 2 Diabetes Mellitus and Metabolic Syndrome

Type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) are diseases caused by the interaction of genetic and non-genetic factors. Therefore, the aim of our study was to investigate the association between six common genetic polymorphisms and T2DM and MetS in males. A total of 120 T2DM, 75 MetS, and 120 healthy controls (HC) were included in the study. ACE ID, eNOS 4a/b, ATR1 A1166C, OXTR (A>G), SOD1 +35A/C, CAT-21A/T gene polymorphisms were genotyped by PCR or PCR-RFLP techniques. T2DM was diagnosed at an earlier age compared to MetS (54 vs 55 years old, p=0.0003) and the difference was greater in carriers of the OXTR G allele (54 vs 56 years old, p=0.0002) or both OXTR G and eNOS b alleles (54 vs 56, p=0.00016). The SOD1 AA genotype (O.R.=0.11, p=0.0006) and the presence of both ACE I and OXTR1 A (O.R.=0.39, p=0.0005) alleles revealed to be protective for T2DM. SOD1 AA and AC genotypes were protective factors for triglyceride (p=0.0002 and p=0.0005, respectively) and HDL cholesterol (p=0.0002 and p=0.0004, respectively) levels in T2DM patients. ACE DD was identified more frequently in hypertensive T2DM patients (O.R.=3.77, p=0.0005) and in those who reported drinking alcohol (p=0.0001) comparing to HC and T2DM patients who did not drink alcohol, respectively. We observed that T2DM patients who reported drinking alcohol had an increased frequency of ACE DD and eNOS bb (p<0.0001), or ACE DD and OXTR G (p<0.0001) compared to non-drinkers. No gene polymorphisms were associated with MetS.

Fisetin Attenuates Diabetic Nephropathy-Induced Podocyte Injury by Inhibiting NLRP3 Inflammasome

Diabetic nephropathy (DN) is one of the primary complications of diabetes. Fisetin is a flavonoid polyphenol that is present in several vegetables and fruits. The present study investigated the mechanisms of fisetin in DN-induced podocyte injury both in vitro and in vivo. The results revealed that fisetin ameliorated high glucose (HG)-induced podocyte injury and streptozotocin (STZ)-induced DN in mice. CDKN1B mRNA expression in the glomeruli of patients with DN decreased based on the Nephroseq dataset, and fisetin reversed CDKN1B expression at mRNA and protein levels in a dose-dependent manner in podocytes and mice kidney tissues. Furthermore, fisetin suppressed the phosphorylation of P70S6K, a downstream target of CDKN1B, activated autophagosome formation, and inhibited Nod-like receptor protein 3 (NLRP3) inflammasomes. Interfering CDKN1B reduced the protective effects of fisetin against high glucose-induced podocyte injury. Molecular docking results revealed a potential interaction between fisetin and CDKN1B. In summary, the present study revealed that fisetin alleviated high glucose-induced podocyte injury and STZ-induced DN in mice by restoring autophagy-mediated CDKN1B/P70S6K pathway and inhibiting NLRP3 inflammasome.

Role of engulfment and cell motility 1 (ELMO1) gene polymorphism in development of diabetic kidney disease

Background

Diabetic kidney disease (DKD) is a progressive kidney disease that affects diabetic patients irrespective of glycemic state or hypertension. Therefore, early detection of DKD is of critical importance. Many genome-wide association studies have identified the engulfment and cell motility 1 (ELMO1) gene as a genetic marker linked to DKD. This study aimed to investigate the association between ELMO1 rs741301 gene polymorphism and the development of DKD among Egyptian patients with type 2 diabetes mellitus (T2DM). Allele and genotype frequencies were investigated in 304 subjects by real-time PCR allelic discrimination assay: 100 DKD patients, 102 diabetic patients without DKD, and 102 healthy controls.

Results

GG genotype of ELMO1 (rs741301) SNP and its allele frequencies were significantly high in all diabetic patients. GG genotype had an odds ratio (OR) of 6.095 and 95% confidence interval (CI) of 2.456–15.125, p < 0.001, while the frequent allele G had an OR of 2.366 and 95% CI of 1.450–3.859, p = 0.001. No significant difference was observed between T2DM without DKD and DKD.

Conclusion

Our results could not establish an association between the ELMO1 rs741301 variant and the progression of DKD.

Interactions Among Non-Coding RNAs in Diabetic Nephropathy

Diabetic Nephropathy (DN) is the most common cause of End-stage renal disease (ESRD). Although various treatments and diagnosis applications are available, DN remains a clinical and economic burden. Recent findings showed that noncoding RNAs (ncRNAs) play an important role in DN progression, potentially can be used as biomarkers and therapeutic targets. NcRNAs refers to the RNA species that do not encode for any protein, and the most known ncRNAs are the microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs). Dysregulation of these ncRNAs was reported before in DN patients and animal models of DN. Importantly, there are some interactions between these ncRNAs to regulate the crucial steps in DN progression. Here, we aimed to discuss the reported ncRNAs in DN and their interactions with critical genes in DN progression. Elucidating these ncRNAs regulatory network will allow for a better understanding of the molecular mechanisms in DN and how they can act as new biomarkers for DN and also as the potential targets for treatment.

Lack of association of genetic variants for diabetic retinopathy in Taiwanese patients with diabetic nephropathy

OBJECTIVE

Diabetic nephropathy (DN) and diabetic retinopathy (DR) comprise major microvascular complications of diabetes that occur with a high concordance rate in patients and are considered to potentially share pathogeneses. In this case-control study, we sought to investigate whether DR-related single nucleotide polymorphisms (SNPs) exert pleiotropic effects on renal function outcomes among patients with diabetes.

RESEARCH DESIGN AND METHODS

A total of 33 DR-related SNPs were identified by replicating published SNPs and via a genome-wide association study. Furthermore, we assessed the cumulative effects by creating a weighted genetic risk score and evaluated the discriminatory and prediction ability of these genetic variants using DN cases according to estimated glomerular filtration rate (eGFR) status along with a cohort with early renal functional decline (ERFD).

RESULTS

Multivariate logistic regression models revealed that the DR-related SNPs afforded no individual or cumulative genetic effect on the nephropathy risk, eGFR status or ERFD outcome among patients with type two diabetes in Taiwan.

CONCLUSION

Our findings indicate that larger studies would be necessary to clearly ascertain the effects of individual genetic variants and further investigation is also required to identify other genetic pathways underlying DN.

The Susceptibility Genes in Diabetic Nephropathy

Background

Diabetes mellitus (DM) poses a severe threat to global public health. Diabetic nephropathy (DN) is one of the most common complications of diabetes and the leading cause of end-stage renal disease (ESRD). Approximately 30-40% of DM patients in the world progress to ESRD, which emphasizes the effect of genetic factors on DN. Family clustering also supports the important role of hereditary factors in DN and ESRD. Therefore, a large number of genetic studies have been carried out to identify susceptibility genes in different diabetic cohorts. Extensive susceptibility genes of DN and ESRD have not been identified until recently.

Summary and Key Messages

Some of these associated genes function as pivotal regulators in the pathogenesis of DN, such as those related to glycometabolism and lipid metabolism. However, the functions of most of these genes remain unclear. In this article, we review several susceptibility genes according to their genetic functions to make it easier to determine their exact effect on DN and to provide a better understanding of the advancements from genetic studies. However, several challenges associated with investigating the genetic factors of DN still exist. For instance, it is difficult to determine whether these variants affect the expression of the protein they encode or other cytokines. More efforts should be made to determine how these genes influence the progression of DN. In addition, many results could not be replicated among races, suggesting that the association between genetic polymorphisms and DN is race-specific. Therefore, large, well-designed studies involving more relevant variables and ethnic groups and more relevant functional studies are urgently needed. These studies may be beneficial and retard the progression of DN by early intervention, especially for patients who carry certain risk alleles or genotypes.