Diabetic nephropathy

A zebrafish model of diabetic nephropathy shows hyperglycemia, proteinuria and activation of the PI3K/Akt pathway

Diabetic nephropathy (DN), as a complication of diabetes, is a substantial healthcare challenge owing to the high risk of morbidity and mortality involved. Although significant progress has been made in understanding the pathogenesis of DN, more efficient models are required to develop new therapeutics. Here, we created a DN model in zebrafish by crossing diabetic Tg(acta1:dnIGF1R-EGFP) and proteinuria-tracing Tg(l-fabp::VDBP-GFP) lines, named zMIR/VDBP. Overfed adult zMIR/VDBP fish developed severe hyperglycemia and proteinuria, which were not observed in wild-type zebrafish. Renal histopathology revealed human DN-like characteristics, such as glomerular basement membrane thickening, foot process effacement and glomerular sclerosis. Glomerular dysfunction was restored upon calorie restriction. RNA sequencing analysis demonstrated that DN zebrafish kidneys exhibited transcriptional patterns similar to those seen in human DN pathogenesis. Notably, the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway was activated, a phenomenon observed in the early phase of human DN. In addition, metformin improved hyperglycemia and proteinuria in DN zebrafish by modulating Akt phosphorylation. Our results indicate that zMIR/VDBP fish are suitable for elucidating the mechanisms underlying human DN and could be a powerful tool for therapeutic discovery.

The Combinational Effect of Inulin and Resveratrol on the Oxidative Stress and Inflammation Level in a Rat Model of Diabetic Nephropathy

Background

Using inulin can enhance resveratrol's effects by improving the intestinal microbiome and the stability of resveratrol.

Objectives

We aimed to investigate the effect of therapeutic intervention with combined inulin and resveratrol on kidney function in diabetic rats.

Methods

Diabetic model was induced by intraperitoneal injection of streptozotocin. Afterward, rats were divided into 6 groups: control, diabetic without treatment, diabetic treated with insulin, diabetic treated with resveratrol, diabetic treated with inulin, and diabetic treated with a combination of inulin and resveratrol. After 10 wk, the creatinine, urea, insulin, urinary proteins, and inflammatory and oxidative stress markers were evaluated. Pathologic changes were examined in kidney tissues.

Results

Renal dysfunction, accompanied by increased inflammation and oxidative stress, was observed. Our results showed that treatment with resveratrol and inulin had antidiabetic effects and was associated with reduced renal dysfunction, oxidative stress, and kidney inflammation. In addition, it was observed that combined treatment with inulin and resveratrol outperformed monotherapies in improving kidney function and reducing oxidative stress and inflammation.

Conclusions

Treatment with resveratrol and inulin can have renoprotective effects by improving oxidative stress and inflammation in kidney tissues. Therefore, employing these 2 compounds is suggested as an inexpensive and available method for diabetic nephropathy.

Prevalence of Microalbuminuria Among Diabetes Patients in Africa: A Systematic Review and Meta-Analysis

Background

Microalbuminuria (MAU) is considered the earliest sign of diabetic nephropathy among diabetes patients. In order to effectively manage diabetic nephropathy and its consequences early, detection of microalbuminuria as soon as possible, especially for diabetes patients, is critical. Therefore, the present study aimed to determine the pooled prevalence of microalbuminuria among diabetes patients in Africa.

Methods

Electronic databases such as Google Scholar, PubMed, African Journals Online, Web of Science, Cochrane Library, EMBASE, and ResearchGate were searched for articles and grey literature. The STATA version 14 software was used to conduct the meta-analysis. I² and Cochran's Q test were employed to assess the presence of heterogeneity between studies. Due to the presence of heterogeneity, a random effect model was used. The publication bias was assessed using the symmetry of the funnel plot and Egger's test statistics. Moreover, subgroup analysis, trim and fill analysis, and sensitivity analysis were also done.

Results

The overall pooled prevalence of microalbuminuria among diabetes patients in Africa was 37.11% (95% CI 31.27-42.95). Substantial heterogeneity was observed between studies, with I² values of 94.7%. Moreover, this meta-analysis showed that the pooled estimate of microalbuminuria among type 1 and type 2 diabetes patients was 35.34% (95% CI: 23.89-46.80, I²=94.2), and 40.24% (95% CI: 32.0-48.47, I²=94.9) respectively. MAU, on the other hand, was more common in people with diabetes for more than 5 years 38.73% (95% CI: 29.34-48.13) than in people with diabetes for less than 5 years 31.48% (95% CI: 18.73-44.23).

Conclusion

This systematic review and meta-analysis found a high prevalence of microalbuminuria among diabetes patients. As a result, early detection of microalbuminuria is critical for preventing and treating microvascular complications such as diabetic nephropathy and the onset of end-stage renal disease.

High intake of dietary phytochemical index may be related to reducing risk of diabetic nephropathy: a case-control study

OBJECTIVE

Diabetic nephropathy (DN) is involved in 40% of patients with type 2 diabetes, Phytochemical index (PI) foods are known as antioxidant and anti-inflammatory agents. Higher intake of phytochemicals can improve glucose tolerance, hypertension and complications of DN. This study sought to discern the relationship between dietary PI and DN.

METHODS

This was a case-control study which was conducted between 210 diabetic women. General characteristics, blood pressure, biochemical serum levels, and anthropometric measurements were evaluated. Physical activity and dietary intakes were assessed via short form of physical activity questionnaire and 147 items-validated food frequency questionnaires, respectively. Then, PI was calculated through method of McCarty and divided to 2 groups of lower and higher of median. Independent samples T tests were used to identify differences in quantitative variables. To investigate the relationship between dietary PI and risk of DN, logistic regression was used. The odds ratio (OR) of DN, and its 95% confidence interval (CI), in each groups of PI were shown.

RESULTS

The percentage of daily intake of energy from fruits and vegetables were higher than the other sources of phytochemical rich foods. Higher consumption of vitamin A was seen in higher group of PI among the control group, after adjusting for energy intake. In the higher adherence of median of dietary PI group, intake of fruits, vegetables, legumes, grains, and olives of controls were higher than cases. In addition, soy consumption was statistically different between lower and higher adherence of median of dietary PI among cases. There was an inverse relationship between dietary PI and risk of DN (OR = 0.44; 95% CI: 0.25-0.77; P = 0.04). After adjusting for potential confounders, the association remained significant, albeit with lower odds of having DN (OR = 0.15; 95% CI: 0.06-0.36; P < 0.001).

CONCLUSION

Finally, the present study found evidence indicating an inverse relationship between consumption of foods rich in phytochemicals and risk of DN in this sample.

Quercetin: an effective polyphenol in alleviating diabetes and diabetic complications

Various studies, especially in recent years, have shown that quercetin has beneficial therapeutic effects in various human diseases, including diabetes. Quercetin has significant anti-diabetic effects and may be helpful in lowering blood sugar and increasing insulin sensitivity. Quercetin appears to affect many factors and signaling pathways involved in insulin resistance and the pathogenesis of type 2 of diabetes. TNFα, NFKB, AMPK, AKT, and NRF2 are among the factors that are affected by quercetin. In addition, quercetin can be effective in preventing and ameliorating the diabetic complications, including diabetic nephropathy, cardiovascular complications, neuropathy, delayed wound healing, and retinopathy, and affects the key mechanisms involved in the pathogenesis of these complications. These positive effects of quercetin may be related to its anti-inflammatory and anti-oxidant properties. In this article, after a brief review of the pathogenesis of insulin resistance and type 2 diabetes, we will review the latest findings on the anti-diabetic effects of quercetin with a molecular perspective. Then we will review the effects of quercetin on the key mechanisms of pathogenesis of diabetes complications including nephropathy, cardiovascular complications, neuropathy, delayed wound healing, and retinopathy. Finally, clinical trials investigating the effect of quercetin on diabetes and diabetes complications will be reviewed.

Single-nucleotide polymorphisms as important risk factors of diabetes among Middle East population

Diabetes is a chronic metabolic disorder that leads to the dysfunction of various tissues and organs, including eyes, kidneys, and cardiovascular system. According to the World Health Organization, diabetes prevalence is 8.8% globally among whom about 90% of cases are type 2 diabetes. There are not any significant clinical manifestations in the primary stages of diabetes. Therefore, screening can be an efficient way to reduce the diabetic complications. Over the recent decades, the prevalence of diabetes has increased alarmingly among the Middle East population, which has imposed exorbitant costs on the health care system in this region. Given that the genetic changes are among the important risk factors associated with predisposing people to diabetes, we examined the role of single-nucleotide polymorphisms (SNPs) in the pathogenesis of diabetes among Middle East population. In the present review, we assessed the molecular pathology of diabetes in the Middle East population that paves the way for introducing an efficient SNP-based diagnostic panel for diabetes screening among the Middle East population. Since, the Middle East has a population of 370 million people; the current review can be a reliable model for the introduction of SNP-based diagnostic panels in other populations and countries around the world.

Assessment of antidiabetic potential of Musa acuminata peel extract and its fractions in experimental animals and characterisation of its bioactive compounds by HPTLC

Musa acuminata is a rich source of nutritional food with acclaimed therapeutic uses. Banana pulp has been reported to possess antidiabetic properties. The present study aimed to investigate antidiabetic potential of Musa acuminata peels and its fractions along with diabetic complications. Animals were divided into various groups (n = 6), EMA 100, 200 and 400 mg/kg/day and various fractions 50 and 100 mg/kg/day along with vehicle administered orally to alloxan-induced diabetic rats (n = 6) for 21 days for extract and for 7 days for fractions. Musa acuminata possess antidiabetic potential by reducing plasma glucose by utilising glucose in the periphery and production of hepatic glycogen and further reduce protein catabolism which is responsible for improvement in body weight along with reduction in diabetic complications such as dyslipidemia, peripheral neuropathy and nephropathy. Protective role of Musa acuminata in treatment of diabetes and its complications.

LncRNA MALAT1 Aggravates Renal Tubular Injury via Activating LIN28A and the Nox4/AMPK/mTOR Signaling Axis in Diabetic Nephropathy

BACKGROUND

Diabetic nephropathy (DN) is a serious complication among patients with diabetes. Elucidating its pathogenesis is crucial for identifying novel biomarkers and therapeutic targets for DN.

METHODS

DN tissues were harvested for examining MALAT1, LIN28A and Nox4. Human kidney-2 (HK-2) cells were treated with high glucose (HG) for establishing a cell model of DN. Cell viability was examined by MTT assay. HG-induced cell apoptosis and secretion of TNF-α and IL-6 were analyzed by TUNEL and ELISA assays, respectively. RIP and RNA pull-down assays were applied to analyze the interaction between MALAT1, LIN28A and Nox4 in HK-2 and human embryonic kidney 293T (HEK-293T) cells. A rat model of DN was established to determine the role of MALAT1 in DN in vivo.

RESULTS

MALAT1, LIN28A and Nox4 were upregulated in DN tissues and HG-treated HK-2 cells. Overexpression of MALAT1, LIN28A or Nox4 reduced cell viability and enhanced cell apoptosis, ROS generation and secretion of inflammatory cytokines in HG-treated HK-2 cells, whereas knockdown of MALAT1, LIN28A or Nox4 exerted opposite effects. Furthermore, MALAT1 directly interacted with LIN28A. Moreover, MALAT1 facilitated the interaction between LIN28A and Nox4 to increase Nox4 stability. Knockdown of Nox4 relieved HG-induced injury by suppressing the AMPK/mTOR signaling in HK-2 cells. Knockdown of MALAT1 alleviated renal tubular epithelial injury by suppressing LIN28A and the Nox4/AMPK/TOR signaling in DN.

CONCLUSION

MALAT1 activates the AMPK/mTOR signaling via interacting with LIN28A to stabilize Nox4 mRNA, thereby aggravating high glucose-induced renal tubular epithelial injury. Our findings provide potential therapeutic targets for DN.

Serum albumin was negatively associated with diabetic peripheral neuropathy in Chinese population: a cross-sectional study

BACKGROUND

Previous studies that explored the relationship of serum albumin with diabetic peripheral neuropathy (DPN) have indicated inconsistent results. Thus, the present study aimed to evaluated the association between serum albumin and DPN, defined as vibration perception threshold (VPT) values ≥ 25 V and/or inability to feel the monofilament, in Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

1465 T2DM patients aged ≥ 16 years, who completed the measurement of serum albumin and DPN screening between 2012 and 2015, were included in the cross-sectional study. Correlation and multivariate logistic regression analysis models were used to evaluate the possible relationship between serum albumin and DPN.

RESULTS

Patients with higher quartiles of serum albumin had significantly lower VPT values and prevalence of DPN compared with those with lower quartiles (P for trend < 0.01), and there was an inverse relationship between serum albumin and VPT values and prevalence of DPN (all P < 0.01). Multivariate logistic regression analysis demonstrated that the risk of DPN was progressively decreased across serum albumin quartiles (P for trend < 0.01), and participants in the highest quartile of serum albumin were at a significantly decreased risk of DPN compared to those in the lowest quartile (odds rate: 0.311, 95% confidence intervals 0.134-0.724, P < 0.01). ROC analysis revealed that the optimal cutoff point of serum albumin for the prevalence of DPN was 39.95 g/L in patients with T2DM, with a sensitivity of 65.88% and a specificity of 66.7%.

CONCLUSIONS

Decreased levels of serum albumin might be correlated with increased risk of DPN in Chinese patients with T2DM. Future longitudinal studies with large samples are warranted to confirm our findings, and elucidate putative mechanisms for the association.

Circular RNA expression profile in transgenic diabetic mouse kidneys

Background

Diabetic nephropathy is one of the most important complications in patients with diabetes. The etiology and pathogenesis of diabetic nephropathy remain unclear. Several studies have indicated that circular RNAs (circRNAs) play crucial regulatory roles in numerous human diseases and normal physiology; however, to date, no study has focused on the comprehensive expression profile of circRNAs in the kidneys of diabetic mice. Therefore, we aimed to identify differentially expressed circRNAs in diabetic mouse kidneys to explore the possible roles of dysregulated circRNAs in diabetic nephropathy development.

Results

Diabetic BKS-Lepr^em2Cd479/Nju (BKS-DB/Nju) mice and their nondiabetic wild-type littermates of C57BL/KsJ wild-type (WT) mice were used as experimental animals. Among all circRNAs identified by high-throughput RNA sequencing, four circRNAs were upregulated and ten were downregulated in diabetic mouse kidneys compared to those in nondiabetic mouse kidneys. After verification using quantitative reverse transcriptase polymerase chain reaction assays, we found that circR_1084, circR_182, circR_4, circR_50, circR_596, circR_897, and circR_203 were downregulated, whereas circR_627, circR_628, circR_735, and circR_801 were upregulated in the renal tissues of 8- and 16-week-old BKS-DB/Nju mice compared to those in WT mice.

Conclusion

We studied the circRNA expression profile in the kidneys of diabetic mice. Differentially expressed circRNAs may be useful as candidate biomarkers for diabetic nephropathy. Collectively, our results provide a novel theoretical basis for further investigation of the regulatory roles of circRNA in the etiology and pathogenesis of diabetic nephropathy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-021-00270-z.

The expression profile of circANKRD36 and ANKRD36 as diagnostic biomarkers of chronic kidney disease in patients with type 2 diabetes mellitus

Background

The molecular mechanisms for chronic kidney disease (CKD) remain largely unknown and appear to be multifactorial. In the current study, we aimed to study the circulatory levels of circular ankyrin repeat domain 36 (circANKRD36) and ANKRD36 in Egyptian patients with type 2 diabetes mellitus (T2DM) and CKD and to explore their associations with the progression of CKD. This cross-sectional controlled study enrolled 60 patients with T2DM and 40 controls. Real-time polymerase chain reaction (RT-PCR) and real-time quantitative PCR (RT-qPCR) analyses were used to detect the expression levels of circANKRD36 and ANKRD36.

Results

Our results detected that the relative expression levels of circANKRD36 and ANKRD36 were significantly higher in patients with T2DM compared to controls. CircANKRD36 and ANKRD36 were significantly overexpressed in patients with macroalbuminuria (0.2316±0.096, 0.0086±0.0035, respectively) compared microalbuminuria (0.1347±0.032, 0.0037±0.0008, respectively) as well as normoalbuminuria (0.1261±0.018, 0.0027±0.0004, respectively), p˂0.001*.

Conclusion

The relative expression levels of circANKRD36 and ANKRD36 were significantly increased in patients with T2DM more specifically in patients with diabetic nephropathy (DN) and macroalbuminuria.

Increased dishevelled associated activator of morphogenesis 2, a new podocyte-associated protein, in diabetic nephropathy

BACKGROUND

Previously, by using proteomic analysis and RNA sequencing in isolated glomeruli, we identified several novel differentially expressed proteins in human and mouse diabetic nephropathy (DN) versus controls, including dishevelled associated activator of morphogenesis 2 (DAAM2). DAAM2 binds the Wnt effector Dvl. We aimed to study possible contributions of DAAM2 to DN.

METHODS

We assessed DAAM2 by immunostaining in non-cancer regions of human nephrectomy (Nx), DN and normal donor kidney tissues. We also examined DAAM2 in DN mice (db/db eNOS-/-) and Nx mice. DN mice treated with angiotensin-converting enzyme inhibitor (ACEI), dipeptidyl peptidase 4 inhibitor (DPP4I) or vehicle were compared. DAAM2 was knocked down in primary cultured podocytes by small interfering RNA to study its effects on cell function.

RESULTS

In normal human glomeruli, DAAM2 was expressed only on podocytes. DAAM2 expression was increased in both Nx and DN versus normal donors. Podocyte DAAM2 expression was increased in DN and Nx mouse models. Glomerular DAAM2 expression correlated with glomerular size and was decreased significantly by ACEI while DPP4I only numerically reduced DAAM2. In primary cultured podocytes, knockdown of DAAM2 enhanced adhesion, slowed migration, activated Wnt-β-catenin signaling and downregulated mammalian target of rapamycin complex 1 (mTORC1) and Rho activity.

CONCLUSIONS

Podocyte DAAM2 is upregulated in both Nx and DN, which could be contributed to by glomerular hypertrophy. We hypothesize that DAAM2 regulates podocyte function through the mTORC1, Wnt/β-catenin and Rho signaling pathways.

Resveratrol: Evidence for Its Nephroprotective Effect in Diabetic Nephropathy

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus (DM). Dietary habits play a major role in determining the onset and progression of DM-related disorders and a proper diet (rich in fruits and vegetables) can delay or prevent the process of DM pathogenesis. Thus, increasing attention has been paid to polyphenols and polyphenol-rich foods since their increased intake has been associated with a reduced incidence of DM and its associated complications. Resveratrol is a polyphenolic phytoalexin that is mainly found in grapevines and berries. It is available in various pharmaceutical dosages and is widely recommended as a dietary supplement due to its beneficial effects. Remarkably, resveratrol's capability to effectively lower blood glucose levels without any side effects has been amply demonstrated in many in vitro and in vivo studies. Herein, we comprehensively review and discuss the nephroprotective effect of resveratrol during DN and its associated mechanisms. Resveratrol exerts its nephroprotective effects via various mechanisms including reducing oxidative stress and advanced glycation end-product (AGE) production, stimulating autophagy, inhibiting endoplasmic reticulum (ER) stress and inflammation, ameliorating lipotoxicity, activating the AMP kinase (AMPK) pathway, and modulating angiogenesis. Moreover, the use of resveratrol as an adjuvant to conventional antidiabetic therapies could be an effective approach to manage DN in humans. However, evidence is scarce to support whether resveratrol has beneficial effects in humans during DN. Therefore, clinical studies are warranted to elucidate resveratrol's role against DN.

A Prospective Single-Blind Randomized Trial of Ramipril, Eplerenone and Their Combination in Type 2 Diabetic Nephropathy

<b><i>Introduction:</i></b> Angiotensin-converting enzyme inhibitors (ACEI) combined with mineralocorticoid receptor antagonists were found to have a beneficial effect on patients with chronic kidney disease. <b><i>Objective:</i></b> The aim of our clinical trial was to compare the antialbuminuric effect of ramipril monotherapy, eplerenone monotherapy and eplerenone/ramipril combination therapy in patients with stage 1 hypertension and type 2 diabetes mellitus. <b><i>Methods:</i></b> In a single-blind, randomized clinical trial, 75 hypertensive patients (stage 1 hypertension) with type 2 diabetes mellitus and microalbuminuria were randomized in a 1:1:1 ratio to 1 of 3 groups: ramipril 10 mg monotherapy (25 patients), eplerenone 50 mg monotherapy (25 patients) and combination therapy of eplerenone/ramipril 50/10 mg (25 patients) through a randomized clinical trial. Blood pressure, urinary albumin/creatinine ratio (UACR), serum creatinine, estimated glomerular filtration rate (eGFR) and serum K level were measured before randomization and after 24 weeks. <b><i>Results:</i></b> Ramipril and eplerenone monotherapy showed a significant lowering of UACR compared with baseline levels (<i>p</i> ≤ 0.0001). The eplerenone/ramipril combination group showed a more significant reduction of UACR compared with the ramipril and eplerenone monotherapy groups (<i>p</i> = 0.0001). There was a more significant lowering of systolic blood pressure in the combination group (<i>p</i> &#x3c; 0.0001). A nonsignificant change of serum potassium level, serum creatinine and eGFR was found among the 3 groups. <b><i>Conclusion:</i></b> Addition of eplerenone to ACEI shows an added antialbuminuric effect without significant change of the serum K level compared with eplerenone or ACEI.

MicroRNA-21 as an Early Marker of Nephropathy in Patients with Type 1 Diabetes

Introduction:

Diabetic nephropathy (DN) is the most common cause of chronic kidney disease worldwide. A major challenge is to identify early diabetic nephropathy. microRNAs (miRNAs) are short noncoding RNA sequences and regulate a wide range of biological processes as cell differentiation, proliferation, cell metabolism and apoptosis. miRNAs may have a role in molecular mechanisms linked to cellular pathways of DN. The aim of this study was to investigate the level of microRNA-21 as a potential marker of early nephropathy in type 1 diabetes mellitus (T1DM).

Methods:

A total number of 340 participants were included and classified into 3 groups; Group I included 100 healthy participants, Group II included 120 patients with T1DM with <5 years duration, and Group III included 120 patients with T1DM with >5 years duration. All participants were submitted to detail clinical examination, laboratory investigations, urinary albumin/creatinine ratio (ACR), estimated glomerular filtration rate (eGFR) as well as plasma microRNA-21 assays.

Results:

Blood pressure and ACR were significantly higher in group III than groups I and II. Further, microRNA-21 was significantly higher in group III than groups I and II, and more in group II than group I. microRNA-21 starts to rise in group II before microalbuminuria. miRNA-21 at a level of 0.01 had a greater sensitivity 94.1% and specificity 100% for identifying DN than ACR at level 45 mg/gm with sensitivity 88.2% and specificity 89%.

Conclusion:

Plasma microRNA-21 can serve as an early marker for diagnosis and identifying diabetic nephropathy in T1DM.

Renal Benefits of SGLT 2 Inhibitors and GLP-1 Receptor Agonists: Evidence Supporting a Paradigm Shift in the Medical Management of Type 2 Diabetes

Diabetic nephropathy (DN) is one of the most perilous side effects of diabetes mellitus type 1 and type 2 (T1DM and T2DM).). It is known that sodium/glucose cotransporter 2 inhibitors (SGLT 2i) and glucagone like peptide-1 receptor agonists (GLP-1 RAs) have renoprotective effects, but the molecular mechanisms are still unknown. In clinical trials GLP-1 analogs exerted important impact on renal composite outcomes, primarily on macroalbuminuria, possibly through suppression of inflammation-related pathways, however enhancement of natriuresis and diuresis is also one of possible mechanisms of nephroprotection. Dapagliflozin, canagliflozin, and empagliflozin are SGLT2i drugs, useful in reducing hyperglycemia and in their potential renoprotective mechanisms, which include blood pressure control, body weight loss, intraglomerular pressure reduction, and a decrease in urinary proximal tubular injury biomarkers. In this review we have discussed the potential synergistic and/or additive effects of GLP 1 RA and SGLT2 inhibitors on the primary onset and progression of kidney disease, and the potential implications on current guidelines of diabetes type 2 management.

Salusin-α mitigates diabetic nephropathy via inhibition of the Akt/mTORC1/p70S6K signaling pathway in diabetic rats

Salusin-α is a bioactive peptide that protects against atherosclerosis and hepatosteatosis. Serum salusin-α level is declined in patients suffering with renal insufficiency. However, it is still undefined whether salusin-α plays a role in diabetic nephropathy. The present study was designed to investigate the potential roles of salusin-α in diabetic renal disease. Herein, we demonstrated that the salusin-α levels in both plasma and kidney tissues from diabetic rats were obviously downregulated. Exogenous administration of salusin-α eliminated the typical characteristics of diabetic nephropathy. Salusin-α treatment decreased renal fibrosis, which was related with reduced epithelial-mesenchymal transition (EMT) of renal tubular epithelial cells. Injection of salusin-α suppressed the production of reactive oxygen species (ROS) via attenuation of NADPH oxidase subunits protein expressions and recovery of the antioxidant system. Mechanistically, the activated Akt/mTORC1/p70S6K signaling pathway in diabetic nephropathy was counteracted by salusin-α treatment. Our results demonstrated that salusin-α exerted protective effect against diabetic nephropathy via reduced oxidative stress and fibrosis, dependent on inactivation of the Akt/mTORC1/p70S6K signaling cascade. Salusin-α may be considered as a promising target for the treatment of diabetic nephropathy.

Genetic associations between genes in the renin-angiotensin-aldosterone system and renal disease: a systematic review and meta-analysis

BACKGROUND

Chronic kidney disease (CKD) is defined by abnormalities in kidney structure and/or function present for more than 3 months. Worldwide, both the incidence and prevalence rates of CKD are increasing. The renin-angiotensin-aldosterone system (RAAS) regulates fluid and electrolyte balance through the kidney. RAAS activation is associated with hypertension, which is directly implicated in causation and progression of CKD. RAAS blockade, using drugs targeting individual RAAS mediators and receptors, has proven to be renoprotective.

OBJECTIVES

To assess genomic variants present within RAAS genes, ACE, ACE2, AGT, AGTR1, AGTR2 and REN, for association with CKD.

DESIGN AND DATA SOURCES

A systematic review and meta-analysis of observational research was performed to evaluate the RAAS gene polymorphisms in CKD using both PubMed and Web of Science databases with publication date between the inception of each database and 31 December 2018. Eligible articles included case-control studies of a defined kidney disease and included genotype counts.

ELIGIBILITY CRITERIA

Any paper was removed from the analysis if it was not written in English or Spanish, was a non-human study, was a paediatric study, was not a case-control study, did not have a renal disease phenotype, did not include data for the genes, was a gene expression-based study or had a pharmaceutical drug focus.

RESULTS

A total of 3531 studies were identified, 114 of which met the inclusion criteria. Genetic variants reported in at least three independent publications for populations with the same ethnicity were determined and quantitative analyses performed. Three variants returned significant results in populations with different ethnicities at p<0.05: ACE insertion, AGT rs699-T allele and AGTR1 rs5186-A allele; each variant was associated with a reduced risk of CKD development.

CONCLUSIONS

Further biological pathway and functional analyses of the RAAS gene polymorphisms will help define how variation in components of the RAAS pathway contributes to CKD.

Mangosteen Vinegar Rind from Garcinia mangostana Prevents High-Fat Diet and Streptozotocin-Induced Type II Diabetes Nephropathy and Apoptosis

Type II diabetes (T2D) nephropathy, a major cause of end-stage kidney disease, progresses and develops from oxidative stress. Natural polyphenols can protect the kidney from diabetic nephropathy exerting antioxidant activities. The present approach enumerates the reno-protective and anti-apoptotic effects of mangosteen vinegar rind (MVR, a phenolic aqueous extract) against high-fat diet (5 g/day up to five weeks)-/streptozotocin (single ip, dose 30 mg/kgBW)-induced T2D nephropathy of albino mice. In vitro total phenolic content, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant capacity, and α-amylase inhibition activity as antidiabetic assay of MVR were performed. In vivo mice body weight, oral glucose, and maltose tolerance test, metabolic parameters (plasma glucose, insulin level, omeostasis model assessment-estimated insulin resistance), biochemical parameters (kidney hypertrophy, blood urea nitrogen, creatinine), oxidative stress parameters (malondialdehyde, superoxide dismutase, catalase) were estimated in an intervention study. Additionally, renal morphology and early apoptosis were observed following the H & E staining and TUNEL assay of the tissue frozen section. We found that the aqueous extract of MVR possesses potent in vitro antioxidative and antidiabetic activities. Animal intervention results showed that MVR 100, 200 mg/kgBW, and Glibenclamide 60 mg/kgBW treatments significantly improved (P < 0.05) the abovementioned parameters compared to the diabetic control group. Furthermore, treatments also significantly restored (P < 0.05) kidney histological alterations and reduced cellular apoptosis compared to the diabetic control group. These findings concluded that MVR treatments significantly modulated the glucose intolerance, metabolic alterations, and oxidative stress-induced pathological alterations and cellular apoptosis of diabetic kidney. PRACTICAL APPLICATION: Garcinia mangostana, a polyphenol rich natural product, is obtained from the tropical rain forest area of Southeast Asian countries and processes diverse biological activities including antioxidant, anti-proliferative, anti-inflammatory, anti-carcinogenic, and so on. This research first time focuses on the nephro-protective and anti-apoptotic effects of mangosteen vinegar rind (MVR) from the mangosteen fruit pericarp. Our study provides the efficient data to prove the beneficial effect of MVR as a dietary supplement for the prevention and management of diabetic nephropathy.

High Glucose-Induced Apoptosis in Human Kidney Cells Was Alleviated by miR-15b-5p Mimics

MicroRNAs were involved in a wide range of biological processes of diabetic nephropathy (DN). It is reported that miR-15b-5p was downregulated in the patients with DN. However, the mechanisms underlying the regulatory effects of miR-15b-5p on patients with diabetes remain unclear. Thus, this study aimed to investigate the role of miR-15b-5p during high glucose (HG)-induced apoptosis in human kidney cells. Quantitative real-time (qRT)-PCR was used to detect the level of miR-15b-5p. CCK-8 assay, EdU staining assays and flow cytometry were used to detect cell proliferation, apoptosis respectively in vitro. In addition, Western blotting was used to determine active caspase-3, cleaved poly(ADP-ribose) polymerase (PARP), phosphorylated (p)-AKT, p-mammalian target of rapamycin (mTOR), p-S6, p-c-Jun N terminal kinase (JNK), p-p38 and p-extracellular signal-regulated kinase (ERK) proteins levels. The expression of miR-15b-5p in patients with DN were dramatically decreased compared with health persons. Similarly, HG down-regulated the expression of miR-15b-5p in HK-2 cells. In contrast, miR-15b-5p mimics alleviated HG-induced apoptosis in HK-2 cells via decreasing the expressions of active caspase 3 and cleaved PARP. EdU detection further confirmed that miR-15b-5p mimics attenuated the anti-proliferation effect of HG in HK-2 cells. Furthermore, HG-induced Akt/mTOR pathway downregulation and JNK upregulation were markedly reversed by miR-15b-5p mimics in cells. The data suggested that miR-15b-5p mimics protects HK-2 cells from HG-induced apoptosis. The anti-apoptotic effects of miR-15b-5p may due to the activation of the Akt/mTOR pathway as well as inactivation of JNK. Taken together, miR-15b-5p might be a potential therapeutic target for the treatment of patients with DN.

Interaction between ELMO1 gene polymorphisms and environment factors on susceptibility to diabetic nephropathy in Chinese Han population

BACKGROUND

The association of diabetic nephropathy (DN) risk with single nucleotide polymorphisms (SNPs) within Engulfment and Cell Motility 1 (ELMO1) gene and gene-environment synergistic effect have not been extensively examined in, therefore, the purpose of this study is to explore the association between multiple SNPs in ELMO1 gene, and the relationship between gene-environment synergy effect and the risk of DN.

METHODS

Genotyping for 4 SNPs was performed with polymerase chain reaction (PCR) and following restriction fragment length polymorphism (RFLP) methods. Hardy-Weinberg balance of the control group was tested by SNPstats (online software: http://bioinfo.iconologia.net/snpstats). The best combination of four SNPs of ELMO1 gene and environmental factors was screened by GMDR model. Logistic regression was used to calculating the OR values between different genotypes of ELMO1 gene and DN.

RESULTS

The rs741301-G allele and the rs10255208-GG genotype were associated with an increased risk of DN risk, adjusted ORs (95% CI) were 1.75 (1.19-2.28) and 1.41 (1.06-1.92), respectively, both p-values were < 0.001. We also found that the others SNPs-rs1345365 and rs7782979 were not significantly associated with susceptibility to DN. GMDR model found a significant gene-alcohol drinking interaction combination (p = 0.0107), but no significant gene-hypertension interaction combinations. Alcohol drinkers with rs741301-AG/GG genotype also have the highest DN risk, compared to never drinkers with rs741301-AA genotype, OR (95% CI) 3.52 (1.93-4.98).

CONCLUSIONS

The rs741301-G allele and the rs10255208-GG genotype, gene-environment interaction between rs741301 and alcohol drinking were all associated with increased DN risk.

The implication of Numb-induced Notch signaling in endothelial-mesenchymal transition of diabetic nephropathy

AIM

This study was purposed to figure out the contribution of Numb-induced Notch signaling to the development of diabetic nephropathy (DN).

METHODS

Two hundred and twenty six DN patients were included, and human glomerular endothelial cells (RGEC) were cultured. MSCV-Numb-IRES-GFP, MSCV-Notch1-IRES-GFP and MSCV-Hes1-IRES-GFP were transfected to construct the recombinant retroviral vectors.

RESULT

The over-expressed Numb and Notch1, as well as the under-expressed Hes-1 were correlated with the undesirable prognosis of DN patients (P < 0.05). Within the cell lines transfection with si-Numb would cut down E-cadherin and CD31 expressions (P < 0.05), yet elevated α-SMA and vimentin expressions (P < 0.05). The apoptotic rate of si-Numb cell lines underperformed ones categorized into the hyperglucose group (P < 0.05), whereas the lowly-expressed Notch1 and Hes1 were observably associated with inhibited proliferation of myofibroblasts (P < 0.05). Addition of ADPT caused under-expressed α-SMA and vimentin, along with the over-expressed E-cadherin and CD31 (P < 0.05). Silencing of Notch1 and Hes1 reversed the epithelial-mesenchymal transition (EMT) process that was triggered by high glucose (P < 0.05).

CONCLUSION

Numb negatively regulated Notch signaling pathway in EMT of DN, implying that they had great potentials to serve as therapeutic targets or diagnostic biomarkers for DN.

Osteomeles schwerinae Extract Prevents Diabetes-Induced Renal Injury in Spontaneously Diabetic Torii Rats

Mesangial cell proliferation contributes to the development of glomerulosclerosis in diabetic nephropathy. This study was aimed at determining whether Osteomeles schwerinae (OSSC) extract can ameliorate renal damage in Spontaneously Diabetic Torii (SDT) rats. OSSC extract (100 and 250 mg/kg/day) was administered to the SDT rats through oral gavage for 17 weeks. At the end of the experiment, glucose, HbA1c, and albuminuria were measured. In addition, the levels of mesangial proliferation-related proteins were determined by western blotting and immunohistochemistry. Our results show that albuminuria, accumulation of the extracellular matrix (ECM), and renal expansion were markedly restored by OSSC extract administration. The OSSC treatment also inhibited α-smooth muscle actin and transforming growth factor-β1 protein expression. In addition, OSSC and its bioactive compounds hyperoside and quercitrin inhibited the platelet-derived growth factor-BB (PDGF-BB)/platelet-derived growth factor-B receptor (PDGFR-β) ligand binding in an in vitro assay. Taken together, these results indicate that OSSC inhibits ECM accumulation and mesangial proliferation of the glomeruli in SDT rats through inhibition of the interaction between PDGF-BB and PDGFR-β. OSSC has ameliorating effects on the initiation and progression of diabetes complications and can be used for the treatment of early diabetic renal dysfunction.

Beneficial Effect of Bis(Hinokitiolato)Zn Complex on High-fat Diet-induced Lipid Accumulation in Mouse Liver and Kidney

BACKGROUND/AIM

Metabolic syndrome-induced lifestyle-related diseases include diabetes mellitus (DM) and hypertension, and Zn-based compounds have effects on DM. We aimed to investigate the ameliorating effects of bis(hinokitiolato)Zn, [Zn(hkt)₂] on lipid metabolism in the liver and kidney, histopathologically.

MATERIALS AND METHODS

We used a high-fat diet (HFD)-fed C57BL/6J mouse model and administered a diet containing 10-20 mg Zn/kg body weight (BW) or 20 mg pioglitazone/kg BW as the positive control. After the treatments, we collected blood, liver, and kidney samples and morphologically evaluated the mouse organs for fat accumulation.

RESULTS

After a 4-month HFD administration, ectopic fat deposition was detected in the liver and kidney. Furthermore, Zn accumulation in the liver and kidney increased following [Zn(hkt)₂] treatment, that reduced lipid accumulations and lipid toxicity in these tissues.

CONCLUSION

The results of this study suggest that [Zn(hkt)₂] could be a novel anti-dyslipidaemia compound for treating diet-induced obesity.

Comorbid Conditions in Canadians Hospitalized Because of Diabetes

OBJECTIVES

The number of hospital discharges involving type 1 or type 2 diabetes as the first-listed diagnosis has increased over the past few decades. Such cases are commonly associated with various comorbidities. We analyzed data collected from hospital separations in Canada to determine the number and proportion of comorbid conditions in Canadians hospitalized because of diabetes.

METHODS

The most responsible diagnosis (MRDx) of diabetes (ICD-10-CA: E10 [type 1 diabetes] or E11 [type 2 diabetes]) was identified from acute care hospital separations (Discharge Abstract Database) from 2013 to 2014 in all Canadian jurisdictions except Quebec. Hospital separations were calculated by 5-year age groups and sex. The most common comorbid (secondary) diagnoses were identified for hospital separations with diabetes as the MRDx, and the average lengths of stay associated with diabetes were determined.

RESULTS

The total number of hospital separations in 2013-2014 in Canada (excluding Quebec) with diabetes as the MRDx in all ages was 30,422, and males represented more than half (58.7%) of the separations. The median age group when diabetes is the MRDx is 60 to 64. For all patients hospitalized with an MRDx of diabetes, there were 2.2% deaths. Hypertension was the most common comorbid diagnosis in patients with diabetes as the MRDx, followed by glomerular disorders, peripheral angiopathy and acute renal failure.

CONCLUSIONS

Hospitalizations resulting from diabetes are associated with vascular comorbidities, and hypertension is the most common. Prevention of shared predisposing factors should reduce the burden of hospitalizations associated with diabetes.

Prevalence of and Factors Associated with Nephropathy in Diabetic Patients Attending an Outpatient Clinic in Harare, Zimbabwe

There is limited information on the burden of diabetic nephropathy in developing countries. This study aimed to determine the prevalence of and factors associated with nephropathy among diabetic patients attending an outpatient clinic in Harare, Zimbabwe. In an analytical cross-sectional study, diabetic patients were consecutively enrolled and a questionnaire administered, clinical assessment conducted, and blood samples collected for human immunodeficiency virus testing and measurement of lipids, creatinine, fructosamine, and glycosylated hemoglobin levels. Urine samples were collected for determination of albumin and creatinine levels, which were used to categorize albuminuria. A total of 344 diabetic patients were enrolled. Overall, just over a third (35.8%) of patients had moderately increased albuminuria and 9.0% had severely increased albuminuria giving an overall prevalence of nephropathy of 44.8%. Prevalence of moderately increased albuminuria was slightly higher (36.5% versus 33.3%) and severely increased albuminuria slightly lower (8.8% versus 9.5%) in type 2 than type 1 diabetes patients, but the difference was not statistically significant (P = 0.866). Higher fructosamine and retinopathy were associated with nephropathy in both univariate and multivariate analysis {higher fructosamine (odds ratio [OR] = 1.00, confidence interval [CI] = 1.00-1.01), and retinopathy (OR = 2.80, CI = 1.64-4.97)}. We report a higher prevalence of moderately increased albuminuria and a lower prevalence of severely increased albuminuria compared with findings reported a decade ago among type 1 and type 2 diabetes mellitus patients attending the same clinic. High fructosamine and retinopathy were independent predictors of nephropathy.

Fenofibrate attenuates diabetic nephropathy in experimental diabetic rat's model via suppression of augmented TGF-β1/Smad3 signaling pathway

CONTEXT

Fibrates, the ligands of peroxisome profileferator-activated receptor-α have been shown to have a renal protective action in diabetic nephropathy (DN).

OBJECTIVE

This study aimed to elucidate the effect of fenofibrate on renal transforming growth factor-β1 (TGF-β1) and Smad3 in Streptozotocin (STZ)-induced DN.

METHODS

Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (55 mg/kg). Diabetic rats were given fenofibrate (100 mg/kg, p.o.). After 12 weeks, diabetic nephropathy biomarkers were assessed. The mRNA expression of collage I and III, TGF-β1 and Smad3 and were detected by RT-PCR.

RESULTS

Fenofibrate reduced significantly serum creatinine, kidney/body weight ratio, serum albumin excretion Collage I & III, TGF-β1 and Smad3 mRNA expression.

CONCLUSIONS

Our results give further insights into the mechanisms underlying the protective role of fenofibrate in DN, suggesting that interference with TGF-β1/Smad3 signaling pathway may be a useful therapeutic approach to prevent DN.

Association of Salivary Osteopontin Levels with Glycaemic Status and Microalbuminuria - in Patients with Type 2 Diabetes Mellitus

INTRODUCTION

The monitoring of glycaemic status in patients with T2DM is mainly through blood tests (Fasting plasma glucose and HbA1c), which are invasive and involves painful pricks. This leads to poor patient compliance and soon could lead to various micro and macro vascular complications, which hamper the quality of life. There are no sensitive and specific markers to predict these complications at the earliest. Sialochemistry has recently gained attention for monitoring chronic diseases. Osteopontin is a phospho-glycoprotein molecule, elevated in many inflammatory conditions.

AIM

The aim of the study was to evaluate the role of serum and salivary osteopontin in Type 2 Diabetes mellitus (T2DM).

MATERIALS AND METHODS

In this case-control study, we recruited 33 cases of T2DM and 31 age and gender matched healthy controls. Body Mass Index (BMI), Waist/Hip Ratio (WHR), Waist Circumference (WC) and blood pressure was recorded. Fasting Plasma Glucose (FPG), salivary glucose, HbA1c, microalbuminuria, systolic BP, serum and salivary osteopontin levels were estimated.

RESULTS

FPG, salivary glucose, HbA1c, microalbuminuria, systolic BP, BMI, waist / hip ratio serum and salivary osteopontin levels were significantly high in T2DM cases compared to control subjects. Serum and salivary osteopontin levels were significantly correlated with HbA1c and microalbuminuria in T2DM cases.

CONCLUSION

Serum and salivary osteopontin levels are significantly elevated in subjects with T2DM and are associated with glycaemic control and microalbuminuria.

Association of APOA5 Gene Promoter Region -1131T>C Polymorphism (rs662799) to Plasma Triglyceride Level in Patients with Type 2 Diabetic Nephropathy

INTRODUCTION

Diabetic Nephropathy (DN), a serious complication of Type 2 Diabetic Mellitus (T2DM), is progressive and susceptibility to DN varies among T2DM patients. ApoA5-1131T>C polymorphism revealed that is strongly associated with triglyceride levels and proposed as a predisposing factor for DN.

AIM

The purpose of this study was to investigate the association -1131T>C ApoA5 gene polymorphism with serum lipids levels in Type 2 diabetic (DM) patients with or without DN in north of Iran (Mazandaran province).

MATERIALS AND METHODS

This study comprised patients with established T2DM (n=161) and controls (n=58). Genotyping of APOA5 -1131T>C polymorphisms was performed by PCR-RFLP. Diabetic patients were divided into two groups: with nephropathy (DN+, n = 90) and without nephropathy (DN-, n = 71). Lipids and lipoproteins were assessed by enzymatic methods.

RESULTS

The genotype frequencies were 63.8 % TT, 31 % TC, 5.2 % CC in controls, 33.8% TT, 52.1 % TC, 14.1 % CC in DN- and 44.4 % TT, 36.7 % TC, 18.9 % CC in DN+ patients. The TC genotype and the CC genotype were overexpressed among DN+ and DN-population in comparison to the control group. The highest and the lowest TG levels in both diabetic patients and controls belonged to CC+TC and TT genotypes, respectively. Furthermore in both patients TG increased with this order: TT< TC<CC.

CONCLUSION

These results suggest that APOA5 -1131T>C polymorphisms influence lipid levels in type 2 diabetic patients.

Effect of angiotensin converting enzyme inhibitor on glomerular hyperfiltration in patients with type 1 diabetes

OBJECTIVE

To assess the effect of angiotensin converting enzyme inhibition on glomerular filtration rate (GFR) in normotensive patient with type 1 diabetes.

METHODS

A two year non-placebo control prospective study was conducted after ethical approval at Diabetes Centre of Diabetic Association of Pakistan, a WHO collaborating centre in Karachi, Pakistan. All patients with type 1 diabetes visited the out-patients department from August 2009 till July 2011 and those who fulfilled the inclusion criteria were invited to participate. A total of 121 people aged ≥18 years and ≥ 5 years of diabetes were included. Pregnant and lactating woman and those aged <18 years were excluded. GFR was calculated by using CKD-EPI formula (eGFR) at baseline and after two year. On the basis of estimated GFR, patients at baseline were divided according to KDIGO classification of chronic kidney diseases into, hyperfiltration (eGFR ≥ 100 ml/min) and normal filtration group (eGFR < 100 ml/min). All subjects in hyperfiltration group received ACE inhibitor (treatment group) while patients with normal filtration did not receive ACE inhibitor (control group).

RESULTS

Fifty two patients (43%) were in the treatment and sixty nine (57%) were in the control group. At baseline eGFR, systolic and diastolic blood pressures between groups were non-significantly different. After two years, compared to baseline, eGFR of the treatment group declined and the control group increased significantly. No significant difference in systolic while diastolic blood pressure of the treatment group increased significantly after two years compared to baseline. In contrast both systolic and diastolic blood pressure of control group increased significantly after two years compared to their baseline values.

CONCLUSION

Present study demonstrated that initiation of ACEI in hyperfiltration stage declined GFR and keep blood pressure within normal range.

Effect of Bergenin on the Kidney of C57BL/6J Mice with High Fat-Diet Induced Oxidative Stress

The present study evaluated the protective effect of bergenin on high fat diet (HFD) induced diabetic mice. C57BL/6J mice were segregated in two groups, one fed standard diet (NC) and the other fed HFD for 16 weeks. Mice were fed continuously with high fat diet for 16 weeks and subjected to intragastric administration of bergenin (10, 20 and 40 mg/kg body weight (BW)), metformin (25 mg/kg BW) 9 to 16 weeks. At the end of the treatment nephritic markers, lipid peroxidation product, antioxidant and histopathological examination were carried out to assess the efficacy of the treatment. HFD fed mice showed increased plasma glucose, insulin, altered nephritic markers, antioxidant and histopathological abnormalities. Oral Treatment with bergenin (40 mg/kg BW) showed near normalized levels of plasma glucose, lipid peroxidation product, antioxidants, improved insulin and reduced kidney damage. The effects of bergenin were comparable with standard drug, metformin. These data suggest that bergenin protect kidney from deleterious effect of glucose.

Kidney Injury Molecule Levels in Type 2 Diabetes Mellitus

BACKGROUND

This study was designed to determine the diagnostic role of urinary kidney injury molecule (KIM)-1 levels in renal damage in patients with type 2 diabetes mellitus according to the urinary albumin/creatinine ratio.

METHODS

Patients with type 2 diabetes mellitus admitted to different polyclinics in our hospital enrolled in the study and were subdivided into three groups according to albumin/creatinine ratio - normalbuminuric (n: 20); microalbuminuric (n: 20); albuminuric (n: 18) - and compared with the control group. Urine albumin was analyzed using the immunoturbidimetric method (Architect C16000, Abbott Diagnostics). uKIM-1 was determined using a commercially available enzyme-linked immunosorbent assay test kit (USCN Life Science, Hankou, Wuhan, China). One-sample Kolmogorov-Smirnov test, Spearman correlation and Kruskal-Wallis non-parametric tests were performed. Post hoc comparisons were made using Bonferroni-corrected Mann-Whitney U tests.

RESULTS

The differences between the controls and normalbuminuric, microalbuminuric and albuminuric groups were highly significant for KIM-1. Positive correlation was found between KIM-1 and urine microalbumin-urine microalbumin/creatinine (r = 0.479 P < 0.001; r = 0. 400, P < 0.001; respectively).

CONCLUSION

In our study, KIM-1 levels were significantly different suggesting that urinary KIM-1 levels may be an early marker in patients with diabetic nephropathy. J. Clin. Lab. Anal. 00:1-6, 2016.

Protective Effects of Curcumin on Renal Oxidative Stress and Lipid Metabolism in a Rat Model of Type 2 Diabetic Nephropathy

PURPOSE

Diabetic nephropathy is a serious complication of type 2 diabetes mellitus, and delaying the development of diabetic nephropathy in patients with diabetes mellitus is very important. In this study, we investigated inflammation, oxidative stress, and lipid metabolism to assess whether curcumin ameliorates diabetic nephropathy.

MATERIALS AND METHODS

Animals were divided into three groups: Long-Evans-Tokushima-Otsuka rats for normal controls, Otsuka-Long-Evans-Tokushima Fatty (OLETF) rats for the diabetic group, and curcumin-treated (100 mg/kg/day) OLETF rats. We measured body and epididymal fat weights, and examined plasma glucose, adiponectin, and lipid profiles at 45 weeks. To confirm renal damage, we measured albumin-creatinine ratio, superoxide dismutase (SOD), and malondialdehyde (MDA) in urine samples. Glomerular basement membrane thickness and slit pore density were evaluated in the renal cortex tissue of rats. Furthermore, we conducted adenosine monophosphate-activated protein kinase (AMPK) signaling and oxidative stress-related nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling to investigate mechanisms of lipotoxicity in kidneys.

RESULTS

Curcumin ameliorated albuminuria, pathophysiologic changes on the glomerulus, urinary MDA, and urinary SOD related with elevated Nrf2 signaling, as well as serum lipid-related index and ectopic lipid accumulation through activation of AMPK signaling.

CONCLUSION

Collectively, these findings indicate that curcumin exerts renoprotective effects by inhibiting renal lipid accumulation and oxidative stress through AMPK and Nrf2 signaling pathway.

Effect of Bergenin on the Kidney of C57BL/6J Mice with High Fat-Diet Induced Oxidative Stress

The present study evaluated the protective effect of bergenin on high fat diet (HFD) induced diabetic mice. C57BL/6J mice were segregated in two groups, one fed standard diet (NC) and the other fed HFD for 16 weeks. Mice were fed continuously with high fat diet for 16 weeks and subjected to intragastric administration of bergenin (10, 20 and 40 mg/kg body weight (BW)), metformin (25 mg/kg BW) 9 to 16 weeks. At the end of the treatment nephritic markers, lipid peroxidation product, antioxidant and histopathological examination were carried out to assess the efficacy of the treatment. HFD fed mice showed increased plasma glucose, insulin, altered nephritic markers, antioxidant and histopathological abnormalities. Oral Treatment with bergenin (40 mg/kg BW) showed near normalized levels of plasma glucose, lipid peroxidation product, antioxidants, improved insulin and reduced kidney damage. The effects of bergenin were comparable with standard drug, metformin. These data suggest that bergenin protect kidney from deleterious effect of glucose.

Alcohol Toxicity in Diabetes and Its Complications: A Double Trouble?

BACKGROUND

Eight percent of the U.S. population has been diagnosed with diabetes mellitus (DM), while another large percentage has gone undiagnosed. As the epidemiology of this disease constitutes a larger percentage of the American population, another factor presents a dangerous dilemma that can exacerbate the hazardous effects imposed by DM. Excessive alcohol consumption concerns the health of more than 50% of all adults. When this heavy-alcohol-drinking population overlaps with DM and its complications, the effects can be dangerous. In this review, we term it as "double trouble."

METHODS

We provide evidence of alcohol-induced exacerbation of organ damage in diabetic conditions. In certain cases, we have explained how diabetes and alcohol induce similar pathological effects.

RESULTS

Known exacerbated complications include those related to heart diseases, liver damage, kidney dysfunction, as well as retinal and neurological impairment. Often, pathophysiological damage concludes with end-stage disorders and even mortality. The metabolic, cell signaling, and pathophysiological changes associated with "double trouble" would lead to the identification of novel therapeutic targets.

CONCLUSIONS

This review summarizes the epidemiology, diagnosis, pathophysiology, metabolic, and cell signaling alterations and finally brushes upon issues and strategies to manage the "double trouble."

Chinese medicines in the treatment of experimental diabetic nephropathy

Diabetic nephropathy (DN) is a severe micro vascular complication accompanying diabetes mellitus that affects millions of people worldwide. End-stage renal disease occurs in nearly half of all DN patients, resulting in large medical costs and lost productivity. The course of DN progression is complicated, and effective and safe therapeutic strategies are desired. While the complex nature of DN renders medicines with a single therapeutic target less efficacious, Chinese medicine, with its holistic view targeting the whole system of the patient, has exhibited efficacy for DN management. This review aims to describe the experimental evidence for Chinese medicines in DN management, with an emphasis on the underlying mechanisms, and to discuss the combined use of herbs and drugs in DN treatment.

Drug Targets for Oxidative Podocyte Injury in Diabetic Nephropathy

Diabetic nephropathy (DN) is one the most prevalent chronic complications of diabetes mellitus that affects as much as one-third of diabetic patients irrespective of the type of diabetes. Hyperglycemia is the key trigger for DN that initiates a number of microscopic and ultramicroscopic changes in kidney architecture. Microscopic changes include thickening of the glomerular basement membrane (GBM), tubular basement membrane (TBM), mesangial proliferation, arteriosclerosis, and glomerulotubular junction abnormalities (GTJA). Among the ultramicroscopic changes, effacement of podocytes and decrease in their density seem to be the centerpiece of DN pathogenesis. These changes in kidney architecture then produce functional deficits, such as microalbuminuria and decreased glomerular filtration rate (GFR). Among several mechanisms involved in inflicting damage to podocytes, injuries sustained by increased oxidative stress turns out to be the most important mechanism. Different variables that are included in increased production of reactive oxygen species (ROS) include a hyperglycemia-induced reduction in glutathione (GSH), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation via hyperglycemia, advanced glycation end products (AGEs), protein kinase C (PKC), and renin-angiotensin-aldosterone system (RAAS). Unfortunately, control of podocyte injury hasn't received much attention as a treatment approach for DN. Therefore, this review article is mainly concerned with the exploration of various treatment options that might help in decreasing the podocyte injury, mainly by reducing the level of NADPH oxidase-mediated generation of ROS. This article concludes with a view that certain NADPH oxidase inhibitors, RAAS inhibitors, statins, antidiabetic drugs, and antioxidant vitamins might be useful in decreasing podocyte injury and resultant structural and functional kidney impairments in DN.

Amelioration of experimentally induced diabetic nephropathy and renal damage by nilotinib

Diabetes mellitus is an ever growing world-wide health problem. The patient has to stick to a firm life-long therapeutic regimen, otherwise diabetic complications will develop. Diabetic nephropathy (DN) is one of the most common diabetic complications and it requires careful medical attendance. Nilotinib hydrochloride is a protein tyrosine kinase inhibitor reported to have numerous therapeutic efficacies besides being an anticancer. In the current study, single I.P. streptozotocin (50 mg/kg) injection was used to induce type I diabetes mellitus in male Sprague-Dawley rats. After 8 weeks, significant deterioration of renal function with urinary excretion of nephrin, podocalyxin, and albumin was observed. Daily oral administration of nilotinib (20 mg/kg) for 8 weeks significantly improved signs of DN on all investigated scales. On a biochemical scale, kidney functions, albuminuria, urinary nephrin, podocalyxin excretion, and host oxidant/antioxidant balance significantly improved. Kidney content of nitric oxide, expression of toll-like receptors 4 and NF-κB/p65 activity significantly declined as well. On a histopathological scale, α-smooth muscle actin and nestin expression significantly declined. Meanwhile, area of fibrosis significantly declined as seen with significant reduction in accumulation of extracellular matrix components and kidney content of collagen. Ultimately, such improvements were accompanied by significant restoration of normal kidney physiology and function. In conclusion, nilotinib can hinder progression of DN through various mechanisms. Reduction of oxidative stress, enhancement of host antioxidant defense system, reduction of inflammation, angiogenesis, tissue hypoxia, and pro-fibrogenic biomarker expression can be implicated in the beneficial therapeutic outcome observed with nilotinib therapy.

Polymorphisms of the UCP2 Gene Are Associated with Glomerular Filtration Rate in Type 2 Diabetic Patients and with Decreased UCP2 Gene Expression in Human Kidney

INTRODUCTION

Uncoupling protein 2 (UCP2) reduces production of reactive oxygen species (ROS) by mitochondria. ROS overproduction is one of the major contributors to the pathogenesis of chronic diabetic complications, such as diabetic kidney disease (DKD). Thus, deleterious polymorphisms in the UCP2 gene are candidate risk factors for DKD. In this study, we investigated whether UCP2 -866G/A, Ala55Val and Ins/Del polymorphisms were associated with DKD in patients with type 2 diabetes mellitus (T2DM), and whether they had an effect on UCP2 gene expression in human kidney tissue biopsies.

MATERIALS AND METHODS

In a case-control study, frequencies of the UCP2 -866G/A, Ala55Val and Ins/Del polymorphisms as well as frequencies of the haplotypes constituted by them were analyzed in 287 T2DM patients with DKD and 281 T2DM patients without this complication. In a cross-sectional study, UCP2 gene expression was evaluated in 42 kidney biopsy samples stratified according to the presence of the UCP2 mutated -866A/55Val/Ins haplotype.

RESULTS

In the T2DM group, multivariate logistic regression analysis showed that the -866A/55Val/Ins haplotype was an independent risk factor for DKD (OR = 2.136, 95% CI 1.036-4.404), although neither genotype nor allele frequencies of the individual polymorphisms differed between case and control groups. Interestingly, T2DM patients carrying the mutated haplotype showed decreased estimated glomerular filtration rate (eGFR) when compared to subjects with the reference haplotype (adjusted P= 0.035). In kidney biopsy samples, UCP2 expression was significantly decreased in UCP2 mutated haplotype carriers when compared to kidneys from patients with the reference haplotype (0.32 ± 1.20 vs. 1.85 ± 1.16 n fold change; adjusted P< 0.000001).

DISCUSSION

Data reported here suggest that the UCP2 -866A/55Val/Ins haplotype is associated with an increased risk for DKD and with a lower eGFR in T2DM patients. Furthermore, this mutated haplotype was associated with decreased UCP2 gene expression in human kidneys.

Diabetic glomerulosclerosis can be the pathogenesis of refractory diabetic macular edema

BACKGROUND

Kidney failure provoked by glomerulosclerosis leads to fluid filtration deficits and other disorders of kidney function. Refractory diabetic macular edema (DME) can be another warning sign of glomerulosclerosis in diabetic patients.

CASE

A 40-year-old Saudi male presented with macular edema that was refractory to all possible medical and surgical ophthalmic interventions in both eyes. The macular edema significantly improved once the patient began systemic treatment for newly diagnosed diabetic glomerulosclerosis. This case report is presented with optical coherence tomography (OCT) documentation of before and after each medical and surgical intervention.

OBSERVATIONS

Considerable improvement occurred after treatment with a systemic angiotensin-converting enzyme inhibitor and diuretic treatment due to newly diagnosed diabetic glomerulosclerosis.

CONCLUSION

Refractory DME can be secondary to diabetic glomerulosclerosis. This case indicates the possibility that systemic intervention may be warranted in cases of refractory DME, and the importance of collaboration between ophthalmologists, endocrinologists, and internists in these cases.

Assessment of vascular function in individuals with hyperglycemia: a cross-sectional study of glucose - induced changes in digital volume pulse

Background

Arterial stiffness is an independent risk factor for cardiovascular disease and its progression may be accelerated in the presence of hyperglycemia, either fasting or postprandial. The current study assessed vascular function in subjects with pre-diabetes hyperglycemia, using digital volume pulse analysis technique.

Methods

We conducted a cross-sectional study examining vascular function in the fasting and postprandial (glucose-induced) state in 44 adults, consisting of 17 subjects with pre-diabetic hyperglycemia and 27 normoglycemic volunteers. Photoplethysmography of the digital volume pulse (DVP) was used to determine stiffness index (SI) and reflective index (RI), as main measures of larger artery stiffness and vascular tone, respectively.

Results

Our results showed a significantly higher (Ln) fasting SI in the hyperglycemic group compared with the control group (2.19 ± 0.32 vs. 1.96 ± 0.22, P = 0.005). However, this pattern reversed after adjustment for potential confounders. In multiple linear regression analysis, (Ln) SI was related to age (β = 0.01, 95% CI: 0.01-0.02, P < 0.001) and systolic blood pressure (SBP) (β = 0.01, 95% CI: 0.00-0.01, P < 0.05), but not with W/H, diastolic blood pressure (DBP), fasting plasma glucose (FPG) or serum lipids. Furthermore, age (β = 0.02, 95% CI: 0.01-0.03, P < 0.001) and mean arterial pressure (MAP) (β = 0.01, 95% CI: 0.00-0.02, P < 0.05) were found as the strong predictors of fasting SI in hyperglycemic group. Neither FPG nor 2-h plasma glucose was a significant predictor for SI in hyperglycemic group, after accounting for age and MAP. Subjects with hyperglycemia had a 15% blunted change in postprandial AUCs for RI, adjusted for the respective baseline measurements (−9.40 ± 3.59 vs. -11.00 ± 2.84%) but these did not attain statistical significance.

Conclusion

Increased arterial stiffness in pre-diabetic subjects is strongly associated with age and MAP. The increased DVP-derived SI reported in patients with pre-diabetic hyperglycemia may result from different frequently accompanied risk factors not just glycemic changes in this range.