Inflammation in diabetic kidney disease

Plantaginis semen ameliorates diabetic kidney disease via targeting the sphingosine kinase 1/sphingosine-1-phosphate pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Plantaginis Semen (PS) is widely utilized as a common herb in several Asian countries, particularly China, due to its diuretic, anti-hypertensive, anti-hyperlipidemic, and anti-hyperglycemic properties. Furthermore, it is acknowledged for its ability to mitigate renal complications associated with metabolic syndrome. Despite its extensive usage, there is limited systematic literature elucidating its therapeutic mechanisms, thus emphasizing the necessity for comprehensive investigations in this field.

AIM

This study aims to comprehensively evaluate the therapeutical potential of PS in treating diabetic kidney disease (DKD) and to elucidate the underlying mechanisms through in vivo and in vitro models.

METHODS

The main composition of PS were characterized using the UPLC-QTOF-MS method. For the in vivo investigation, a mouse model mediated by streptozocin (STZ) associated with a high-fat diet (HFD) and unilateral renal excision was established. The mice were split into 6 groups (n = 8): control group (CON group), DKD group, low-dose of Plantago asiatica L. seed extract group (PASE-L group, 3 g/kg/d), medium-dose of PASE group (PASE-M, 6 g/kg/d), high-dose of PASE group (PASE-H, 9 g/kg/d), and positive drug group (valsartan, VAS group, 12 mg/kg/d). After 8 weeks of treatment, the damage induced by DKD was evaluated by using relevant parameters of urine and blood. Furthermore, indicators of inflammation and factors associated with the SphK1-S1P signaling pathway were investigated. For the in vitro study, the cell line HBZY-1 was stimulated by high glucose (HG), they were then co-cultured with different concentrations of PASE, and the corresponding associated inflammatory and sphingosine kinase 1/sphingosine-1-phosphate (SphK1-S1P) factors were examined.

RESULTS

A total of 59 major components in PS were identified, including flavonoids, iridoids, phenylethanol glycosides, guanidine derivatives, and fatty acids. In the mouse model, PS was found to significantly improve body weight, decrease fasting blood glucose (FBG) levels, increased glucose tolerance and insulin tolerance, improved kidney-related markers compared to the DKD group, pathological changes in the kidneys also improved dramatically. These effects showed a dose-dependent relationship, with higher PASE concentrations yielding significantly better outcomes than lower concentrations. However, the effects of the low PASE concentration were not evident for some indicators. In the cellular model, the high dose of PASE suppressed high glucose (HG) stimulated renal mesangial cell proliferation, suppressed inflammatory factors and NF-κB, and decreased the levels of fibrillin-1(FN-1) and collagen IV(ColIV).

CONCLUSION

Our results indicate that PS exerts favorable therapeutic effects on DKD, with the possible mechanisms including the inhibition of inflammatory pathways, suppression of mRNA levels and protein expressions of SphK1 and S1P, consequently leading to reduced overexpression of FN-1 and ColIV, thereby warranting further exploration.

Molecular mechanisms of diabetic nephropathy: A narrative review

Diabetic nephropathy (DN) is the predominant secondary nephropathy resulting in global end-stage renal disease. It is attracting significant attention in both domestic and international research due to its widespread occurrence, fast advancement, and limited choices for prevention and treatment. The pathophysiology of this condition is intricate and involves multiple molecular and cellular pathways at various levels. This article provides a concise overview of the molecular processes involved in the development of DN. It discusses various factors, such as signaling pathways, cytokines, inflammatory responses, oxidative stress, cellular damage, autophagy, and epigenetics. The aim is to offer clinicians a valuable reference for DN's diagnosis, treatment, and intervention.

Urinary biomarkers in diabetic nephropathy

Diabetic nephropathy (DN), a significant consequence of diabetes, is associated with adverse cardiovascular and renal disease as well as mortality. Although microalbuminuria is considered the best non-invasive marker for DN, better predictive markers are needed of sufficient sensitivity and specificity to detect disease in general and in early disease specifically. Even prior to appearance of microalbuminuria, urinary biomarkers increase in diabetics and can serve as accurate nephropathy biomarkers even in normoalbuminuria. In this review, a number of novel urine biomarkers including those reflecting kidney damage caused by glomerular/podocyte damage, tubular damage, oxidative stress, inflammation, and intrarenal renin-angiotensin system activation are discussed. Our review also includes emerging biomarkers such as urinary microRNAs. These short noncoding miRNAs regulate gene expression and could be utilized to identify potential novel biomarkers in DN development and progression. .

A candidate panel of eight urinary proteins shows potential of early diagnosis and risk assessment for diabetic kidney disease in type 1 diabetes

Diabetic kidney disease (DKD) poses a significant health challenge for individuals with diabetes. At its initial stages, DKD often presents asymptomatically, and the standard for non-invasive diagnosis, the albumin-creatinine ratio (ACR), employs discrete categorizations (normal, microalbuminuria, macroalbuminuria) with limitations in sensitivity and specificity across diverse population cohorts. Single biomarker reliance further restricts the predictive value in clinical settings. Given the escalating prevalence of diabetes, our study uses proteomic technologies to identify novel urinary proteins as supplementary DKD biomarkers. A total of 158 T1D subjects provided urine samples, with 28 (15 DKD; 13 non-DKD) used in the discovery stage and 131 (45 DKD; 40 pDKD; 46 non-DKD) used in the confirmation. We identified eight proteins (A1BG, AMBP, AZGP1, BTD, RBP4, ORM2, GM2A, and PGCP), all of which demonstrated excellent area-under-the-curve (AUC) values (0.959 to 0.995) in distinguishing DKD from non-DKD. Furthermore, this multi-marker panel successfully segregated the most ambiguous group (microalbuminuria) into three distinct clusters, with 80% of subjects aligning either as DKD or non-DKD. The remaining 20% exhibited continued uncertainty. Overall, the use of these candidate urinary proteins allowed for the better classification of DKD and offered potential for significant improvements in the early identification of DKD in T1D populations.

Diabetes and Renal Complications: An Overview on Pathophysiology, Biomarkers and Therapeutic Interventions

Diabetic kidney disease (DKD) is a major microvascular complication of both type 1 and type 2 diabetes. DKD is characterised by injury to both glomerular and tubular compartments, leading to kidney dysfunction over time. It is one of the most common causes of chronic kidney disease (CKD) and end-stage renal disease (ESRD). Persistent high blood glucose levels can damage the small blood vessels in the kidneys, impairing their ability to filter waste and fluids from the blood effectively. Other factors like high blood pressure (hypertension), genetics, and lifestyle habits can also contribute to the development and progression of DKD. The key features of renal complications of diabetes include morphological and functional alterations to renal glomeruli and tubules leading to mesangial expansion, glomerulosclerosis, homogenous thickening of the glomerular basement membrane (GBM), albuminuria, tubulointerstitial fibrosis and progressive decline in renal function. In advanced stages, DKD may require treatments such as dialysis or kidney transplant to sustain life. Therefore, early detection and proactive management of diabetes and its complications are crucial in preventing DKD and preserving kidney function.

Effects of dried okra extract on lipid profile, renal function and some RAGE-related inflammatory genes expression in patients with diabetic nephropathy: A randomized controlled trial

BACKGROUND

Diabetic nephropathy (DN) is a common complication of type 2 diabetes. Okra (Abelmoschus esculentus L) is reported to have anti-diabetic effects. The present study aimed to investigate the effects of dried okra extract (DOE) supplementation on lipid profile, renal function indices, and expression of inflammatory genes, as well as serum level of soluble Receptor for Advanced glycation end products (sRAGE) in patients with DN.

METHODS

In this triple-blind randomized placebo-controlled clinical trial, 64 eligible patients with DN received either 125 mg of DOE or placebo daily along with DN-related nutritional recommendations for 10 weeks. Changes in kidney indices including proteinuria and estimated glomerular filtration rate (eGFR), lipid profile, serum SRAGE, as well as the expression of RAGE, ICAM-1, and IL-1 genes were measured over 10 weeks.

RESULTS

After adjustment for the potential confounders, between-group analyses showed no significant differences in terms of lipid profile, kidney function indices, sRAGE, and RAGE-related inflammatory genes expression after 10 weeks.

CONCLUSION

Daily 125 mg DOE along with nutritional recommendations on top of usual care did not lead to significant changes in renal function indices, lipid profile, and inflammatory genes expression in patients with DN.

Update on Diabetic Kidney Disease (DKD): Focus on Non-Albuminuric DKD and Cardiovascular Risk

The classic description of diabetic kidney disease (DKD) involves progressive stages of glomerular hyperfiltration, microalbuminuria, proteinuria, and a decline in the estimated glomerular filtration rate (eGFR), leading to dialysis. In recent years, this concept has been increasingly challenged as evidence suggests that DKD presents more heterogeneously. Large studies have revealed that eGFR decline may also occur independently from the development of albuminuria. This concept led to the identification of a new DKD phenotype: non-albuminuric DKD (eGFR < 60 mL/min/1.73 m², absence of albuminuria), whose pathogenesis is still unknown. However, various hypotheses have been formulated, the most likely of which is the acute kidney injury-to-chronic kidney disease (CKD) transition, with prevalent tubular, rather than glomerular, damage (typically described in albuminuric DKD). Moreover, it is still debated which phenotype is associated with a higher cardiovascular risk, due to contrasting results available in the literature. Finally, much evidence has accumulated on the various classes of drugs with beneficial effects on DKD; however, there is a lack of studies analyzing the different effects of drugs on the various phenotypes of DKD. For this reason, there are still no specific guidelines for therapy in one phenotype rather than the other, generically referring to diabetic patients with CKD.

Diabetic vascular diseases: molecular mechanisms and therapeutic strategies

Vascular complications of diabetes pose a severe threat to human health. Prevention and treatment protocols based on a single vascular complication are no longer suitable for the long-term management of patients with diabetes. Diabetic panvascular disease (DPD) is a clinical syndrome in which vessels of various sizes, including macrovessels and microvessels in the cardiac, cerebral, renal, ophthalmic, and peripheral systems of patients with diabetes, develop atherosclerosis as a common pathology. Pathological manifestations of DPDs usually manifest macrovascular atherosclerosis, as well as microvascular endothelial function impairment, basement membrane thickening, and microthrombosis. Cardiac, cerebral, and peripheral microangiopathy coexist with microangiopathy, while renal and retinal are predominantly microangiopathic. The following associations exist between DPDs: numerous similar molecular mechanisms, and risk-predictive relationships between diseases. Aggressive glycemic control combined with early comprehensive vascular intervention is the key to prevention and treatment. In addition to the widely recommended metformin, glucagon-like peptide-1 agonist, and sodium-glucose cotransporter-2 inhibitors, for the latest molecular mechanisms, aldose reductase inhibitors, peroxisome proliferator-activated receptor-γ agonizts, glucokinases agonizts, mitochondrial energy modulators, etc. are under active development. DPDs are proposed for patients to obtain more systematic clinical care requires a comprehensive diabetes care center focusing on panvascular diseases. This would leverage the advantages of a cross-disciplinary approach to achieve better integration of the pathogenesis and therapeutic evidence. Such a strategy would confer more clinical benefits to patients and promote the comprehensive development of DPD as a discipline.

Association between neutrophil/lymphocyte ratio and kidney impairment in type 2 diabetes mellitus: A role of extracellular water/total body water ratio

AIMS

We explored the predictive utility of baseline neutrophil/lymphocyte ratio (NLR), which reflects a systemic inflammatory tone, in kidney impairment in type 2 diabetes mellitus (T2DM); and investigated the effect of extracellular water/total body water (ECW/TBW) ratio on the relationship.

METHODS

This longitudinal study included 1,224 T2DM adults recruited from a single centre. Cox regression analyses examined the association between NLR and progressive kidney function decline or albuminuria progression. Improvements in risk discrimination were assessed using Harrell's concordance-statistics. The mediatory role of ECW/TBW ratio estimated by bioelectrical impedance was evaluated.

RESULTS

Higher baseline NLR levels were observed in cases with kidney function decline or albuminuria progression over a median 2-year follow-up. NLR independently predicted progressive kidney function decline (hazard ratio:1.39, 95% CI:1.21-1.60, P < 0.001) or albuminuria progression (hazard ratio:1.34, 95% CI:1.08-1.68, P = 0.009). Addition of NLR to a base model comprising demographics, T2DM duration, metabolic and renal parameters, and medications significantly improved the risk discrimination of kidney function decline (P = 0.022) but not albuminuria progression. ECW/TBW ratio accounted for 19.7% of the total effect between NLR and kidney function loss.

CONCLUSIONS

Increased NLR reflecting systemic inflammation is associated with progressive kidney function decline in T2DM, partially explained by dysregulated body fluid balance.

Effect of Selenium Nanoparticles and/or Bee Venom against STZ-Induced Diabetic Cardiomyopathy and Nephropathy

The main purpose of our study was to examine the role of selenium nanoparticles (SeNPs) and/or bee venom (BV) in ameliorating diabetic cardiomyopathy (DCM) and nephropathy (DN) at the biochemical, histopathological and molecular levels. Fifty male albino rats were used in this experiment, divided into five groups: control, Streptozocin (STZ) diabetic, STZ-diabetic treated with SeNPs, STZ-diabetic treated with BV, and STZ-diabetic treated with SeNPs and BV. Biochemically, STZ injection resulted in a significant increase in serum glucose, BUN, creatinine, CRP, CK-MB, AST, LDH and cardiac troponins with a significant decrease in the serum insulin and albumin concentrations. Histopathologically, STZ injection resulted in diabetes, as revealed by glomerulonephritis, perivascular hemorrhage, inflammatory cell infiltrations and fibrosis, with widening of interstitial spaces of cardiomyocytes, loss of muscle cells continuity and some hyaline degeneration. At the molecular levels, the expression levels of miRNA 328, miRNA-21, TGFβ1, TGFβ1R, JAK1, STST-3, SMAD-1 and NFκβ genes were significantly up-regulated, whereas the expression levels of SMAD-7 were significantly down-regulated. It is concluded that SeNPs and/or BV administration ameliorates the deleterious effects resulting from STZ administration through improving the biochemical, histopathological and molecular effects, suggesting their protective role against the long-term diabetic complications of DCM and DN.

The Role of Oxidative Stress-Mediated Inflammation in the Development of T2DM-Induced Diabetic Nephropathy: Possible Preventive Action of Tannins and Other Oligomeric Polyphenols

Diabetic nephropathy is manifested in more than 10% of people with diabetes. It is a common cause of kidney failure and end-stage kidney disease. Understanding of mechanisms underlying the initiation and development of diabetes-induced kidney injuries will allow for the development of more effective methods of prevention and treatment of the disease. Diabetic nephropathy is a wide-ranging complication of diabetes, and it is necessary to discuss the "weight" of pro-inflammatory pathways and molecules in the progress of renal injuries during the development of the disease. A large spectrum of pro-inflammatory molecules and pathways participate in different stages of the pathophysiological progression of diabetic nephropathy, including pro-inflammatory cytokines, chemokines, their receptors, adhesion molecules, and transcription factors. On the other hand, it is known that one of the consequences of hyperglycemia-induced ROS generation is the up-regulation of pro-inflammatory cascades, which, in turn, activate the transcription of genes encoding cytokines-chemokines, growth factors, and extracellular matrix proteins. It is a proven fact that a variety of plant secondary metabolites, such as tannins, flavonoids, and other polyphenols, demonstrate significant anti-diabetic, redox-modulating properties and effectively modulate the inflammatory response. Thus, this review is discussing the possible role of plant phenols in the prevention and treatment of diabetic nephropathy.

Renal Health Improvement in Diabetes through Microbiome Modulation of the Gut-Kidney Axis with Biotics: A Systematic and Narrative Review of Randomized Controlled Trials

Diabetes mellitus is the most common endocrine disorder worldwide, with over 20% of patients ultimately developing diabetic kidney disease (DKD), a complex nephropathic complication that is a leading cause of end-stage renal disease. Various clinical trials have utilized probiotics, prebiotics, and synbiotics to attempt to positively modulate the gut microbiome via the gut-kidney axis, but consensus is limited. We conducted a multi-database systematic review to investigate the effect of probiotics, prebiotics, and synbiotics on various biomarkers of renal health in diabetes, based on studies published through 10 April 2022. Adhering to the Cochrane Collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, relevant articles were systematically screened and extracted by independent reviewers; subsequently, results were systematically compiled, analyzed, and expanded through a narrative discussion. A total of 16 publications encompassing 903 diabetic individuals met the inclusion criteria. Our findings show that some studies report statistically significant changes in common renal markers, such as serum creatinine, estimated glomerular filtration rate, blood urea nitrogen/urea, microalbuminuria, and uric acid, but not on serum albumin, sodium, potassium, phosphorous, or total urine protein. Interestingly, these nutraceuticals seem to increase serum uric acid concentrations, an inflammatory marker usually associated with decreased renal health. We found that probiotics from the Lactobacillus and Bifidobacterium families were the most investigated, followed by Streptococcus thermophilus. Prebiotics including inulin, galacto-oligosaccharide, and resistant dextrin were also examined. The single-species probiotic soymilk formulation of Lactobacillus plantarum A7 possessed effects on multiple renal biomarkers in DKD patients without adverse events. We further investigated the optimum nutraceutical formulation, discussed findings from prior studies, described the gut-kidney axis in diabetes and DKD, and finally commented on some possible mechanisms of action of these nutraceuticals on renal health in diabetics. Although probiotics, prebiotics, and synbiotics have shown some potential in ameliorating renal health degradation in diabetes via gut-kidney axis crosstalk, larger and more convincing trials with focused objectives and next-generation nutraceutical formulations are required to investigate their possible role as adjunct therapy in such patients.

Renoprotective effects of the ginger (Zingiber officinale) on Diabetic kidney disease, current knowledge and future direction: a systematic review of animal studies

OBJECTIVE

Diabetic kidney disease affects approximately 40% of diabetic patients and is the leading cause of chronic kidney disease (CKD) worldwide. As a result, preventing renal complications in diabetic patients is critical. Ginger (Zingiber Officinale Rosco) is a popular spice and natral medicine. The present study was a systematic review focused on the existing evidence of the renoprotective effect of ginger extract on some features of diabetic kidney disease.

METHODS

The literature was searched in online databases such as PubMed, Scopus, EMBASE, ProQuest databases, and Google Scholar from inception to July 2022.

RESULTS

This review included 41 articles that met the eligibility criteria. Ginger supplementation was found to be associated with a significant decrease in blood glucose in 28 studies. Nine studies showed a significant reduction in malondialdehyde (MDA) after supplementation. Also, seventeen studies showed decreased serum levels of creatinine. Fifteen studies reported a decrease in total cholesterol (TC) and fourteen studies showed a lowered triglycerides (TG) concentrations. In twenty-six studies, ginger reduced renal injuries due to diabetes.

CONCLUSION

Ginger may improve blood sugar indices, lipid profile, some inflammatory markers, oxidative stress, and pathologic injuries in diabetic kidney disease. However, future well-designed clinical trials and meta-analyses are required for a solid consensus.

Dynamics of Gut Microbiota and Clinical Variables after Ketogenic and Mediterranean Diets in Drug-Naïve Patients with Type 2 Diabetes Mellitus and Obesity

Type 2 diabetes mellitus (T2DM), the most common form of diabetes, is a progressive chronic metabolic disease that has increasingly spread worldwide, enhancing the mortality rate, particularly from cardiovascular diseases (CVD). Lifestyle improvement through diet and physical activity is, together with drug treatment, the cornerstone of T2DM management. The Mediterranean diet (MD), which favors a prevalence of unprocessed vegetable foods and a reduction in red meats and industrial foods, without excluding any food category, is usually recommended. Recently, scientific societies have promoted a very low-calorie ketogenic diet (VLCKD), a multiphasic protocol that limits carbohydrates and then gradually re-introduces them, with a favorable outcome on body weight and metabolic parameters. Indeed, gut microbiota (GM) modifications have been linked to overweight/obesity and metabolic alterations typical of T2DM. Diet is known to affect GM largely, but only a few studies have investigated the effects of VLCKD on GM, especially in T2DM. In this study, we have compared anthropometric, biochemical, lifestyle parameters, the quality of life, and the GM of eleven patients with recently diagnosed T2DM and overweight or obesity, randomly assigned to two groups of six and five patients who followed the VLCKD (KETO) or hypocaloric MD (MEDI) respectively; parameters were recorded at baseline (T0) and after two (T2) and three months (T3). The results showed that VLCKD had more significant beneficial effects than MD on anthropometric parameters, while biochemical improvements did not statistically differ. As for the GM, despite the lack of significant results regarding the alpha and beta diversity, and the Firmicutes/Bacteroidota ratio between the two groups, in the KETO group, a significant increase in beneficial microbial taxa such as Verrucomicrobiota phylum with its members Verrucomicrobiae, Verrucomicrobiales, Akkermansiaceae, and Akkermansia, Christensenellaceae family, Eubacterium spp., and a reduction in microbial taxa previously associated with obesity (Firmicutes and Actinobacteriota) or other diseases (Alistipes) was observed both at T2 and T3. With regards to the MEDI group, variations were limited to a significant increase in Actinobacteroidota phylum at T2 and T3 and Firmicutes phylum at T3. Moreover, a metagenomic alteration linked to some metabolic pathways was found exclusively in the KETO group. In conclusion, both dietary approaches allowed patients to improve their state of health, but VLCKD has shown better results on body composition as well as on GM profile.

Renal fibrosis as a hallmark of diabetic kidney disease: Potential role of targeting transforming growth factor-beta (TGF-β) and related molecules

INTRODUCTION

Diabetic kidney disease (DKD) is the most common cause of end-stage renal disease (ESRD) worldwide. Currently, there is no effective treatment to completely prevent DKD progression to ESRD. Renal fibrosis and inflammation are the major pathological features of DKD, being pursued as potential therapeutic targets for DKD.

AREAS COVERED

Inflammation and renal fibrosis are involved in the pathogenesis of DKD. Anti-inflammatory drugs have been developed to combat DKD but without efficacy demonstrated. Thus, we have focused on the mechanisms of TGF-β-induced renal fibrosis in DKD, as well as discussing the important molecules influencing the TGF-β signaling pathway and their potential development into new pharmacotherapies, rather than targeting the ligand TGF-β and/or its receptors, such options include Smads, microRNAs, histone deacetylases, connective tissue growth factor, bone morphogenetic protein 7, hepatocyte growth factor, and cell division autoantigen 1.

EXPERT OPINION

TGF-β is a critical driver of renal fibrosis in DKD. Molecules that modulate TGF-β signaling rather than TGF-β itself are potentially superior targets to safely combat DKD. A comprehensive elucidation of the pathogenesis of DKD is important, which requires a better model system and access to clinical samples via collaboration between basic and clinical researchers.

The Role of Platelets in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is among the most common microvascular complications in patients with diabetes, and it currently accounts for the majority of end-stage kidney disease cases worldwide. The pathogenesis of DKD is complex and multifactorial, including systemic and intra-renal inflammatory and coagulation processes. Activated platelets play a pivotal role in inflammation, coagulation, and fibrosis. Mounting evidence shows that platelets play a role in the pathogenesis and progression of DKD. The potentially beneficial effects of antiplatelet agents in preventing progression of DKD has been studied in animal models and clinical trials. This review summarizes the current knowledge on the role of platelets in DKD, including the potential therapeutic effects of antiplatelet therapies.

Increased neutrophil count Is associated with the development of chronic kidney disease in patients with diabetes

BACKGROUND

This study aims to investigate the potential association of peripheral inflammatory blood cell parameters with the incidence and progression of chronic kidney disease (CKD) in patients with diabetes.

METHODS

The cross-sectional study included 1192 subjects with diabetes derived from one center. The cohort study included 2060 subjects with diabetes derived from another two centers followed up for 4 years. Logistic regression and Cox proportional hazards models were used to evaluate the association of peripheral inflammatory blood cell with CKD.

RESULTS

In the cross-sectional study, neutrophil count performed best as an independent risk factor for CKD (odds ratio 2.556 [95% confidence interval 1.111, 5.879]) even after 1:1 case-control matching for age, gender, history of high blood pressure and duration of diabetes. Spline regression revealed a significant linear association of CKD incidence with continuous neutrophil count in excess of 3.6 × 10⁹ /L. In the cohort study, subjects were grouped based on tertile of neutrophil count and neutrophil-to-lymphocyte ratio. Cox regression analysis results showed that only neutrophil count was independently associated with CKD progression (the highest group vs. the lowest group, hazard ratio 2.293 [95% confidence interval 1.260, 4.171]) after fully adjusting for potential confounders. The cumulative incidence of CKD progression in patients with diabetes gradually increased with increasing neutrophil count (53 (7.7%) subjects in the lowest group vs. 60 (8.2%) in the middle group vs. 78 (12.2%) in the highest group).

CONCLUSIONS

This study suggested that neutrophil count is an independent risk factor for progression of CKD in patients with diabetes.

Galaxaura elongata Extract (GE) Modulates Vanadyl Sulfate-Induced Renal Damage via Regulating TGF-β/Smads and Nrf2/NF-κB Pathways

Nephrotoxicity becomes a provoked problem as the kidneys are the target of many chemotherapies. For this reason, we aimed to study the protective effect of Galaxaura elongata extract (GE) against the vanadyl sulfate (Van) induced nephrotoxicity in rats. Forty Wistar albino rats (male) were divided into four groups (n = 10) as follows: control group: rats received 0.5% carboxymethyl cellulose (CMC). Galaxa group: rats received GE at a dose (100 mg/kg orally) daily for 6 weeks. Van group: rats injected with Van at a dose (50 mg/kg i.p.) once weekly for 6 successive weeks. Galaxa + Van group: rats received GE at a dose (100 mg/kg orally) daily for 6 weeks concurrently with Van at a dose (50 mg/kg i.p.) for 6 weeks. Our results showed that Van significantly raised urea and creatinine serum levels as compared to the control group as well as disordered renal oxidative/antioxidant redox. Administration of GE with Van alleviated the adverse impact of Van over the kidney tissues. Furthermore, GE administration in Galaxa + Van group downregulates angiotensin-converting enzyme (ACE1) mRNA expression, angiotensin II (Ang II) concentration, transforming growth factor β (TGF-β) mRNA expression and protein concentration and Nuclear factor κB (NF-κB) mRNA expression as compared to Van group. Also, GE administration caused a noticeable upregulation of Nrf2 and heme oxygenase-1 (HO-1) expressions with a consequent decrease of DNA fragmentation % compared to Van group. The results of the current study show that simultaneous treatment with GE can alleviate nephrotoxicity caused by Van in diabetic rats. The GE treatment of the Van treated animals restored altered renal oxidative/antioxidant redox values towards normal and lessened fibrosis. These results are consistent with these effects being caused by interactions with the TGF-B/Smads and Nrf2/NF-κB signaling pathways.

The Preventive Effects of Fermented and Germinated Foxtail Millet Whole Grain on Kidney Damage in a Diabetic Mouse Model

Diabetic kidney disease (DKD) is an important complication of diabetes. The prevention of DKD can effectively reduce the mortality rate of diabetic patients and improve their quality of life. The present study examined the effects of fermented and germinated foxtail millet whole grain (FG-FM) on kidney lesions in a diabetic mouse model (Db/Db mice). The results proved that the FG-FM consumption significantly alleviated the kidney tissue damage in the diabetic mouse model. The transcriptome analysis of kidney tissues demonstrated that the overactivation of signaling pathways related to inflammation and immunity in the diabetic mouse model was significantly inhibited with the FG-FM intake. Moreover, the consumption of the FG-FM diet effectively elevated the bacterial diversity, increased the relative abundance of probiotics and decreased the relative abundance of previously reported DKD-related bacteria in the gut microbiota of diabetic mice. Our study confirmed foxtail millet as a potential source of functional food for the non-pharmacological intervention of DKD.

Improving the residual risk of renal and cardiovascular outcomes in diabetic kidney disease: A review of pathophysiology, mechanisms, and evidence from recent trials

Based on global estimates, almost 10% of adults have diabetes, of whom 40% are estimated to also have chronic kidney disease (CKD). Almost 2 decades ago, treatments targeting the renin-angiotensin system (RAS) were shown to slow the progression of kidney disease. More recently, studies have reported the additive benefits of antihyperglycaemic sodium-glucose co-transporter-2 inhibitors in combination with RAS inhibitors on both CKD progression and cardiovascular outcomes. However, these recent data also showed that patients continue to progress to kidney failure or die from kidney- or cardiovascular-related causes. Therefore, new agents are needed to address this continuing risk. Overactivation of the mineralocorticoid (MR) receptor contributes to kidney inflammation and fibrosis, suggesting that it is an appropriate treatment target in patients with diabetes and CKD. Novel, selective non-steroidal MR antagonists are being studied in these patients, and the results of two large recently completed clinical trials have shown that one such treatment, finerenone, significantly reduces CKD progression and cardiovascular events compared with standard of care. This review summarizes the pathogenic mechanisms of CKD in type 2 diabetes and examines the potential benefit of novel disease-modifying agents that target inflammatory and fibrotic factors in these patients.

Repurposing a clinically approved prescription Colquhounia root tablet to treat diabetic kidney disease via suppressing PI3K/AKT/NF-kB activation

Background

Growing clinical evidences show the potentials of Colquhounia root tablet (CRT) in alleviating diabetic kidney disease (DKD). However, its pharmacological properties and underlying mechanisms remain unclear.

Methods

‘Drug target-Disease gene’ interaction network was constructed and the candidate network targets were screened through evaluating node genes' topological importance. Then, a DKD rat model induced by high-fat diet/streptozotocin was established and used to determine pharmacological effects and network regulatory mechanisms of CRT against DKD, which were also verified using HK2 cell model induced by high glucose.

Results

The candidate network targets of CRT against DKD were involved into various type II diabetes-related and nephropathy-related pathways. Due to the topological importance of the candidate network targets and the important role of the imbalance between immunity and inflammation in the pathogenesis of DKD, PI3K/AKT/NF-кB signaling-mediated immune-modulatory and anti-inflammatory actions of CRT were selected to be experimentally verified. On the basis of high-fat diet (HFD) / streptozotocin (STZ)-induced DKD rat model, CRT effectively reduced the elevated level of blood glucose, decreased the accumulation of renal lipid, suppressed inflammation and the generation of ECM proteins, and ameliorated kidney function and the renal histopathology through inhibiting the activation of PI3K, AKT and NF-кB proteins, reducing the nuclear accumulation of NF-кB protein and the serum levels of downstream cytokines, which were in line with the in vitro findings.

Conclusions

Our data suggest that CRT may be the promising candidate drug for treating DKD via reversing the imbalance of immune-inflammation system mediated by the PI3K/AKT/NF-кB/IL-1β/TNF-α signaling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00563-7.

Association Between High-Sensitivity C-Reactive Protein and Diabetic Kidney Disease in Patients With Type 2 Diabetes Mellitus

OBJECTIVE

High-sensitivity C-reactive protein (hs-CRP) is an inflammatory marker. This study aimed to identify the correlation between hs-CRP levels and diabetic kidney disease (DKD) in patients with type 2 diabetes mellitus (T2DM).

MATERIALS/METHODS

This cross-sectional and observational study included 927 patients with T2DM. We collected the data of patients based on their medical data, including sociodemographic characteristics, concomitant diseases, laboratory results, and medical therapy. Multivariate logistic regression analysis was conducted to assess the relationship between hs-CRP levels and DKD. A restricted cubic spline (RCS) was used to assess the correlation of hs-CRP levels on a continuous scale with the DKD.

RESULTS

In total, 927 patients were recruited in our study. The median age of the recruited patients was 55 years, and there were 346 female patients and 581 male patients. The hs-CRP levels were evidently higher in patients with DKD than those without DKD. After adjusting for age, sex, diastolic blood pressure, systolic blood pressure, body mass index, neck circumference, waist circumference, hypertension, duration of diabetes, common carotid artery plaque, fasting plasma glucose, glycated hemoglobin, hemoglobin, erythrocyte, leukocyte, γ-glutamyl transferase, albumin, urea nitrogen, uric acid and triglyceride, a significant increase in the odds ratios (ORs) for DKD in the fourth hs-CRP quartile compared with the first quartile was observed (P value for trend= 0.003), and the ORs (95% confidence intervals) in the fourth quartile of hs-CRP were 1.968 (1.244-3.114) for DKD compared to the first quartile.. Moreover, the RCS curves presented a positive association between hs-CRP and DKD in total subjects, male subjects and female subjects, respectively.

CONCLUSIONS

The results of our study indicated that hs-CRP levels were significantly and positively correlated with the presence of DKD, which may provide predictive and diagnostic values in clinical practice.

Qing-Re-Xiao-Zheng Formula Modulates Gut Microbiota and Inhibits Inflammation in Mice With Diabetic Kidney Disease

Evidence indicates that the metabolic inflammation induced by gut microbiota dysbiosis contributes to diabetic kidney disease. Prebiotic supplementations to prevent gut microbiota dysbiosis, inhibit inflammatory responses, and protect the renal function in DKD. Qing-Re-Xiao-Zheng formula (QRXZF) is a Traditional Chinese Medicine (TCM) formula that has been used for DKD treatment in China. Recently, there are growing studies show that regulation of gut microbiota is a potential therapeutic strategy for DKD as it is able to reduce metabolic inflammation associated with DKD. However, it is unknown whether QRXZF is effective for DKD by regulating of gut microbiota. In this study, we investigated the reno-protective effect of QRXZF by exploring its potential mechanism between gut microbiota and downstream inflammatory pathways mediated by gut-derived lipopolysaccharide (LPS) in the kidney. High-fat diet (HFD) and streptozotocin injection-induced DKD mice model was established to assess the QRXZF effect in vivo. Mice treated with QRXZF for 8 weeks had significantly lower levels of urinary albumin, serum cholesterol and triglycerides. The renal injuries observed through histological analysis were attenuated as well. Also, mice in the QRXZF group had higher levels of Zonula occludens protein-1 (ZO-1) expression, lower levels of serum fluorescein-isothiocyanate (FITC)-dextran and less-damaged colonic mucosa as compared to the DKD group, implying the benefit role for the gut barrier integrity. QRXZF treatment also reversed gut dysbiosis and reduced levels of gut-derived LPS. Notably, the expression of toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB), which are important inflammation pathways in DKD, were suppressed in the QRXZF groups. In conclusion, our results indicated that the reno-protective effects of QRXZF was probably associated with modulating gut microbiota and inhibiting inflammatory responses in the kidney.

Diagnostic performance of kidney injury molecule-1 for detection of abnormal urinary albumin-to-creatinine ratio in type 2 diabetes mellitus

In this study, we aimed to investigate whether serum and urinary levels of kidney injury molecule 1 (KIM-1) are increased in type 2 diabetes mellitus (DM) patients with albuminuria. While the correlation of urinary KIM-1 with renal impairment has been well established, the association with serum KIM-1 has not yet been so well documented. The present pilot study included Egyptian patients with type 2 diabetes (T2D): A total of 84 patients with T2D (age 49-64 years; 20 men) were included in the analysis of the present study. They were divided into two groups according to Alb/Cr ratio: the first group included 32 patients (38.1%) with abnormal Alb/Cr ratio (38.6 mg/g·Cr), and the second group included 52 patients with normal Alb/Cr ratio (17.9 mg/g·Cr). Serum and urinary KIM-1 were measured using enzyme-linked immunoassays. There was a significant difference between both serum and urine KIM-1 and Alb/Cr ratio. Patients with abnormal Alb/Cr ratio had significantly higher serum and urinary KIM-1. These results yielded sensitivity (75.0%) and specificity (96.2%) regarding serum KIM-1 with a cut-off point of 37.5 pg/mL, and sensitivity (93.8%) and specificity (88.5%) regarding urinary KIM1 with a cut-off point of 32.00 ng/g.Cr. Serum KIM-1 and urinary KIM-1 were significantly correlated with eGFR and Alb/Cr ratio. In this pilot study, we found that urinary, serum, and urinary levels of KIM-1 are associated with significant impairments in renal function among diabetic patients. Our results also showed that serum and urine KIM-1 can be used as potential biomarkers for diabetic kidney disease.

The effect of underlying inflammation on iron metabolism, cardiovascular risk and renal function in patients with type 2 diabetes

Aim

To investigate the impact of inflammation on iron metabolism, cardiovascular risk and renal function in type 2 diabetes (T2D).

Methods

A total of 50 patients with T2D were included in this study. The patients were stratified into two groups based on their levels of C-reactive protein (CRP), namely normal and high levels (n = 25/group). All laboratory tests were measured using standardised methods.

Results

Fasting plasma glucose levels were elevated in patients with high CRP when compared to those with normal levels (p = 0.0413). Total serum iron levels were lower in patients with high CRP levels (12.78 ± 3.50) when compared to those with normal levels (15.26 ± 4.64), p = 0.0381. However, ferritin and transferrin levels were comparable between the groups (p > 0.05). The mean cell volume (MCV) in the high CRP group was lower (87.66 ± 3.62) than the normal level group (90.79 ± 4.52), p = 0.0096, whilst the lipograms were similar (p > 0.05). The estimated glomerular filtration rate (eGFR) was lower in the high CRP group (98.06 ± 11.64) than the normal level group (104.7 ± 11.11), p = 0.046. Notably, CRP levels were negatively associated with serum iron levels (r = -0.38, p = 0.0061), MCV (r = -0.41, p = 0.0031), potassium (r = -0.37, p = 0.0086) and sodium levels (r = -0.28, p = 0.0471). Regression analyses showed that only CRP (β = -0.16, standard error [SE]: 0.06, p = 0.0125) and sodium (β = 0.51, SE: 0.25, p = 0.0434) levels contributed significantly to the prediction of serum iron levels.

Conclusion

Underlying inflammation in T2D is associated with increased incidence of hypertension and reduced levels of serum iron, MCV and renal function. Although there was no apparent clinical anaemia or renal dysfunction in these patients, mitigating inflammation may be effective in circumventing the ultimate development of iron deficiency anaemia and chronic kidney disease in T2D.

Chronic Inflammation in Chronic Kidney Disease Progression: Role of Nrf2

Despite recent advances in the management of chronic kidney disease (CKD), morbidity and mortality rates in these patients remain high. Although pressure-mediated injury is a well-recognized mechanism of disease progression in CKD, emerging data indicate that an intermediate phenotype involving chronic inflammation, oxidative stress, hypoxia, senescence, and mitochondrial dysfunction plays a key role in the etiology, progression, and pathophysiology of CKD. A variety of factors promote chronic inflammation in CKD, including oxidative stress and the adoption of a proinflammatory phenotype by resident kidney cells. Regulation of proinflammatory and anti-inflammatory factors through NF-κB- and nuclear factor, erythroid 2 like 2 (Nrf2)-mediated gene transcription, respectively, plays a critical role in the glomerular and tubular cell response to kidney injury. Chronic inflammation contributes to the decline in glomerular filtration rate (GFR) in CKD. Whereas the role of chronic inflammation in diabetic kidney disease (DKD) has been well-elucidated, there is now substantial evidence indicating unresolved inflammatory processes lead to fibrosis and eventual end-stage kidney disease (ESKD) in several other diseases, such as Alport syndrome, autosomal-dominant polycystic kidney disease (ADPKD), IgA nephropathy (IgAN), and focal segmental glomerulosclerosis (FSGS). In this review, we aim to clarify the mechanisms of chronic inflammation in the pathophysiology and disease progression across the spectrum of kidney diseases, with a focus on Nrf2.

Advances in understanding the innate immune-associated diabetic kidney disease

Millions of human deaths occur annually due to chronic kidney disease, caused by diabetic kidney disease (DKD). Despite having effective drugs controlling the hyperglycemia and high blood pressure, the incidence of DKD is increasing, which indicates the need for the development of novel therapies to control DKD. In this article, we discussed the recent advancements in the basic innate immune mechanisms in renal tissues triggered under the diabetes environment, leading to the pathogenesis and progression of DKD. We also summarized the currently available innate immune molecules-targeting therapies tested against DKD in clinical and preclinical settings, and highlighted additional drug targets that could potentially be employed for the treatment of DKD. The improved understanding of the disease pathogenesis may open avenues for the development of novel therapies to rein in DKD, which consequently, can reduce morbidity and mortality in humans in the future.

Study of the Active Components and Molecular Mechanism of Tripterygium wilfordii in the Treatment of Diabetic Nephropathy

We aimed to explore the active ingredients and molecular mechanism of Tripterygium wilfordii (TW) in the treatment of diabetic nephropathy (DN) through network pharmacology and molecular biology. First, the active ingredients and potential targets of TW were obtained through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and related literature materials, and Cytoscape 3.7.2 software was used to construct the active ingredient-target network diagram of TW. Second, the target set of DN was obtained through the disease database, and the potential targets of TW in the treatment of DN were screened through a Venn diagram. A protein interaction network diagram (PPI) was constructed with the help of the String platform and Cytoscape 3.7.2. Third, the ClueGO plug-in tool was used to enrich the GO biological process and the KEGG metabolic pathway. Finally, molecular docking experiments and cell pathway analyses were performed. As a result, a total of 52 active ingredients of TW were screened, and 141 predicted targets and 49 target genes related to DN were identified. The biological process of GO is mediated mainly through the regulation of oxygen metabolism, endothelial cell proliferation, acute inflammation, apoptotic signal transduction pathway, fibroblast proliferation, positive regulation of cyclase activity, adipocyte differentiation and other biological processes. KEGG enrichment analysis showed that the main pathways involved were AGE-RAGE, vascular endothelial growth factor, HIF-1, IL-17, relaxin signalling pathway, TNF, Fc epsilon RI, insulin resistance and other signaling pathways. It can be concluded that TW may treat DN by reducing inflammation, reducing antioxidative stress, regulating immunity, improving vascular disease, reducing insulin resistance, delaying renal fibrosis, repairing podocytes, and reducing cell apoptosis, among others, with multicomponent, multitarget and multisystem characteristics.

Results from the Effects of MEtformin on cardiovasculaR function in AdoLescents with type 1 Diabetes (EMERALD) study: A brief report of kidney and inflammatory outcomes

Youth with type 1 diabetes (T1D) demonstrate insulin resistance, independently of glycaemia, when compared to normoglycaemic peers. Insulin resistance increases the risk of cardiovascular disease and diabetic kidney disease, factors also associated with systemic inflammation. We evaluated the effect of metformin on markers of inflammation and diabetic kidney disease in adolescents with T1D. EMERALD, a double-blind, randomized, placebo-controlled trial of 3 months of metformin in 48 participants aged 12-21 years with T1D, included baseline and follow-up assessments of serum creatinine and cystatin C to estimate glomerular filtration rate (eGFR), aspartate aminotransferase, alanine aminotransferase, high-sensitivity C-reactive protein, white blood count, platelets, adiponectin, leptin, and urine albumin: creatinine ratio (UACR). Metformin was associated with a 13.9 mL/min/1.73 m² (95% confidence interval 4.7-23.1 mL/min/1.73 m² ) increase in estimated GFR by serum creatinine versus placebo (P ≤ 0.01), with a significant difference remaining after multivariable adjustments (P = 0.03). Whereas eGFR measured by serum creatinine increased significantly after metformin treatment, no differences were observed in cystatin C, UACR, or systemic inflammatory markers. Additional studies with directly measured GFR in response to metformin in T1D are needed.

Geroprotective effects of Alzheimer's disease drug candidates

Geroprotectors are compounds that slow the biological aging process in model organisms and may therefore extend healthy lifespan in humans. It is hypothesized that they do so by preserving the more youthful function of multiple organ systems. However, this hypothesis has rarely been tested in any organisms besides C. elegans and D. melanogaster. To determine if two life-extending compounds for Drosophila maintain a more youthful phenotype in old mice, we asked if they had anti-aging effects in both the brain and kidney. We utilized rapidly aging senescence-accelerated SAMP8 mice to investigate age-associated protein level alterations in these organs. The test compounds were two cognition-enhancing Alzheimer's disease drug candidates, J147 and CMS121. Mice were fed the compounds in the last quadrant of their lifespan, when they have cognitive deficits and are beginning to develop CKD. Both compounds improved physiological markers for brain and kidney function. However, these two organs had distinct, tissue-specific protein level alterations that occurred with age, but in both cases, drug treatments restored a more youthful level. These data show that geroprotective AD drug candidates J147 and CMS121 prevent age-associated disease in both brain and kidney, and that their apparent mode of action in each tissue is distinct.

Leaf Extracts of Anchomanes difformis Ameliorated Kidney and Pancreatic Damage in Type 2 Diabetes

Kidney disease in diabetes is one of the common microvascular complications of diabetes mellitus implicated in end-stage renal failure. This study explored the ability of Anchomanes difformis to ameliorate kidney and pancreatic damage in type 2 diabetes mellitus using male Wistar rats. Two weeks of fructose (10%) administration followed by streptozotocin (40 mg/kg) were used to induce type 2 diabetes. Leaf extract (aqueous) of Anchomanes difformis (200 mg and 400 mg/kgBW) was administered orally for six weeks. Body weights were monitored, urea and creatinine were measured. Interleukins (IL)-1β, IL-6, IL-10, IL-18, and TNFα were measured in the kidney lysate. CAT, SOD, ORAC, FRAP, and MDA levels were also evaluated in the kidney. Transcription factors (Nrf2 and NF-ĸB/p65) and apoptotic markers (Bcl2 and caspase 3) were investigated in the kidney. Histological sections of the pancreas and kidney tissues were examined for any visible pathology. Supplementation with Anchomanesdifformis enhanced antioxidant status, modulated inflammatory response, and reduced apoptosis in the kidney. It also restored the kidney and pancreatic histoarchitecture of the treated diabetic rats. The pathophysiology associated with diabetic nephropathy and pancreatic damage showcase the importance of exploring the use of antidiabetic, nephroprotective agents such as Anchomanes difformis to kidney damage in type 2 diabetes.

Diagnostic Performance of Biomarkers Urinary KIM-1 and YKL-40 for Early Diabetic Nephropathy, in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis

There is a lack of prediction markers for early diabetic nephropathy (DN) in patients with type 2 diabetes mellitus (T2DM). The aim of this systematic review and meta-analysis was to evaluate the performance of two promising biomarkers, urinary kidney injury molecule 1 (uKIM-1) and Chitinase-3-like protein 1 (YKL-40) in the diagnosis of early diabetic nephropathy in type 2 diabetic patients. A comprehensive search was performed on PubMed by two reviewers until May 2020. For each study, a 2 × 2 contingency table was formulated. Sensitivity, specificity, and other estimates of accuracy were calculated using the bivariate random effects model. The hierarchical summary receiver operating characteristic curve hsROC) was used to pool data and evaluate the area under curve (AUC). The sources of heterogeneity were explored by sensitivity analysis. Publication bias was assessed using Deek’s test. The meta-analysis enrolled 14 studies involving 598 healthy individuals, 765 T2DM patients with normoalbuminuria, 549 T2DM patients with microalbuminuria, and 551 T2DM patients with macroalbuminuria, in total for both biomarkers. The AUC of uKIM-1 and YKL-40 for T2DM patients with normoalbuminuria, was 0.85 (95%CI; 0.82–0.88) and 0.91 (95%CI; 0.88–0.93), respectively. The results of this meta-analysis suggest that both uKIM-1 and YKL-40 can be considered as valuable biomarkers for the early detection of DN in T2DM patients with the latter showing slightly better performance than the former.

Oxidative Stress Markers in Chronic Kidney Disease with Emphasis on Diabetic Nephropathy

Diabetes prevalence is increasing worldwide, especially through the increase of type 2 diabetes. Diabetic nephropathy occurs in up to 40% of diabetic patients and is the leading cause of end-stage renal disease. Various factors affect the development and progression of diabetic nephropathy. Hyperglycaemia increases free radical production, resulting in oxidative stress, which plays an important role in the pathogenesis of diabetic nephropathy. Free radicals have a short half-life and are difficult to measure. In contrast, oxidation products, including lipid peroxidation, protein oxidation, and nucleic acid oxidation, have longer lifetimes and are used to evaluate oxidative stress. In recent years, different oxidative stress biomarkers associated with diabetic nephropathy have been found. This review summarises current evidence of oxidative stress biomarkers in patients with diabetic nephropathy. Although some of them are promising, they cannot replace currently used clinical biomarkers (eGFR, proteinuria) in the development and progression of diabetic nephropathy.

Influence of melatonin on the kidneys of rats with experimental diabetes mellitus type 2

Diabetes mellitus is characterized by numerous pathological changes in the body. Under conditions of diabetes, hyperglycemic intoxication of the organism rapidly develops, which in turn leads to an increase of oxidative stress with subsequent disturbance of the anatomical and functional integrity of the components of organisms. Today, the search for the substances that would contribute to the multi-vectoral effect on the negative consequences of diabetes is actively being pursued. Melatonin is one of such substances. In this work, we studied the effect of melatonin on oxidative stress markers (oxidized products content, activities of superoxide dismutase and catalase), the concentration of metabolism end products (creatinine and urea), main ions concentration (potassium and chlorine), and protein content (total protein and electropherogram in polyacrylamide gel), enzymatic activity of gamma-glutamyltrasferase in the cytosolic fraction of rat kidneys under condition of type 2 diabetes mellitus (EDM2). Experimental studies were performed on 18 white adult Wistar rats divided into three groups (control, group with EDM2 and group with EDM2, which were treated with melatonin). The increase of concentration of oxidized products, the activity of catalase and gamma-glutamyltrasferase, creatinine, urea, K+ and Cl– and the decrease of concentration of superoxide dismutase in the rats’ kidneys was noted after development of EDM2. The electrophoretic proteinogram of the cytosolic proteins obtained from the rats’ kidneys showed an increase of content of high-molecular-weight and a decrease of low-molecular-weight proteins. Administration of melatonin in a dose of 10 mg/kg of body weight for 7 days after development of EDM2 restored the studied parameters almost to the control group values. Therefore, the influence of melatonin can prevent chronic development of oxidative stress in kidneys under hyperglycemic intoxication, and lead to normalization of kidney function and the restoration of homeostasis.

Renal expression of cytokines and chemokines in diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease worldwide. Inflammatory mediators have been implicated in the pathogenesis of DN, thus considered an inflammatory disease. However, further studies are required to assess the renal damage caused by the action of these molecules. Therefore, the objective of this study was to analyze the expression of cytokines and chemokines in renal biopsies from patients with DN and to correlate it with interstitial inflammation and decreased renal function.

METHODS

Forty-four native renal biopsies from patients with DN and 23 control cases were selected. In situ expression of eotaxin, MIP-1α (macrophage inflammatory protein-1α), IL-8 (interleukin-8), IL-4, IL-10, TNF-α (tumor necrosis factor-α), TNFR1 (tumor necrosis factor receptor-1), IL-1β, and IL-6 were evaluated by immunohistochemistry.

RESULTS

The DN group showed a significant increase in IL-6 (p < 0.0001), IL-1β (p < 0.0001), IL-4 (p < 0.0001) and eotaxin (p = 0.0012) expression, and a decrease in TNFR1 (p = 0.0107) and IL-8 (p = 0.0262) expression compared to the control group. However, there were no significant differences in IL-10 (p = 0.4951), TNF-α (p = 0.7534), and MIP-1α (p = 0.3816) expression among groups. Regarding interstitial inflammation, there was a significant increase in IL-6 in scores 0 and 1 compared to score 2 (p = 0.0035), in IL-10 in score 2 compared to score 0 (p = 0.0479), and in eotaxin in score 2 compared to scores 0 and 1 (p < 0.0001), whereas IL-8 (p = 0.0513) and MIP-1α (p = 0.1801) showed no significant differences. There was a tendency for negative correlation between eotaxin and estimated glomerular filtration rate (eGFR) (p = 0.0566).

CONCLUSIONS

Our results indicated an increased in situ production of cytokines and chemokines in DN, including IL-6, IL-1β, IL-4, and eotaxin. It was observed that, possibly, eotaxin may have an important role in the progression of interstitial inflammation in DN and in eGFR decrease of these patients.

Neutrophil-to-lymphocyte ratio is a predictor of renal dysfunction in Japanese patients with type 2 diabetes

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR) has been widely evaluated as a biomarker in various medical and surgical prognoses, but its usefulness in diabetic kidney disease is not yet known.

METHODS

This prospective observational study included outpatients, comprised of 184 men aged 73 ± 11 (mean ± standard deviation) years and 174 women aged 76 ± 10 years at baseline, from a rural hospital. We examined the relationship between baseline NLR calculated by analyzing the differential leukocyte counts in the complete blood count and the 2-year estimated glomerular filtration rate (eGFR) decline rate (i.e. 2-year eGFR-baseline eGFR) ∗100/baseline eGFR. Rapid eGFR decline rate was defined as a value < -25%.

RESULTS

Multiple linear regression analysis using rapid eGFR decline rates as objective variables, adjusted for confounding factors as explanatory variables, showed that NLR (β = 0.138, p = 0.007) as well as presence of antidyslipidemic medication, hemoglobinA1c, and urinary albumin excretion stage were significantly and independently associated with a rapid eGFR decline rate. The multivariate-adjusted odds ratios (95% confidence interval) of the 2nd and 3rd tertiles of baseline NLR for rapid eGFR decline rate were 3.62 (0.70-18.7) and 8.03 (1.54-41.9), respectively. Multivariate-adjusted mean eGFR (95% confidence interval) values after 2 years categorized by tertile of baseline NLR were: 1st, 63.9 (61.8-66.1); 2nd, 60.8 (58.7-62.9); and 3rd, 58.9 (56.8-61.0).

CONCLUSIONS

These results suggest that baseline NLR might be a useful biomarker for renal function decline in outpatients with diabetes.

Pathogenic Pathways and Therapeutic Approaches Targeting Inflammation in Diabetic Nephropathy

Diabetic nephropathy (DN) is associated with an increased morbidity and mortality, resulting in elevated cost for public health systems. DN is the main cause of chronic kidney disease (CKD) and its incidence increases the number of patients that develop the end-stage renal disease (ESRD). There are growing epidemiological and preclinical evidence about the close relationship between inflammatory response and the occurrence and progression of DN. Several anti-inflammatory strategies targeting specific inflammatory mediators (cell adhesion molecules, chemokines and cytokines) and intracellular signaling pathways have shown beneficial effects in experimental models of DN, decreasing proteinuria and renal lesions. A number of inflammatory molecules have been shown useful to identify diabetic patients at high risk of developing renal complications. In this review, we focus on the key role of inflammation in the genesis and progression of DN, with a special interest in effector molecules and activated intracellular pathways leading to renal damage, as well as a comprehensive update of new therapeutic strategies targeting inflammation to prevent and/or retard renal injury.

Increased circulating cytokine levels in African American women with obesity and elevated HbA1c

PURPOSE

Obesity has emerged as one of the biggest health crisis and is the leading cause of death and disabilities around the world. BMI trends suggest that majority of the increase in T2D is resulting from the increased prevalence of obesity. In fact, 85.2% of people with T2D are overweight or obese. The highest prevalence for obesity is seen in non-Hispanic, African American women (56.6%). T2D is classified as an inflammatory disease because of elevated, circulating pro-inflammatory cytokines and acute-phase inflammatory proteins. This study was designed to determine how high HbA1c and serum glucose correlate with circulatory cytokine levels in obese, African American women.

METHODS

We investigated cytokine/chemokine serum levels using a multiplex assay. Then we used Pairwise Pearson Correlation Test to determine the relationship between clinical metabolic parameters and cytokine/chemokine serum levels.

RESULTS

The results indicated that participants with elevated HbA1c exhibited an up regulation of IL-3, IL-4, IL-7, TNF-α, IFN-α2 and CX3CL1 serum levels compared to participants with normal HbA1c. These cytokines were also correlated with several clinical metabolic parameters.

CONCLUSIONS

The results suggest that IL-3, IL-4, IL-7, TNF-α, IFN-α2 and CX3CL1 serum levels may contribute to the development and onset of type 2 diabetes.

Alpha1-Antitrypsin in Urinary Extracellular Vesicles: A Potential Biomarker of Diabetic Kidney Disease Prior to Microalbuminuria

PURPOSE

Diabetic kidney disease (DKD), which is related to inflammation and immune response, is the primary vascular complication of diabetes mellitus and also the leading etiology of end-stage renal disease. Urinary extracellular vesicles (UEVs) are an attractive source for biomarker detection as they involve molecular constituents derived from their parental sections of the nephron. In this study, we aimed to search for a potential biomarker in UEVs for the early diagnosis and prediction of DKD, especially before the emergence of microalbuminuria.

PATIENTS AND METHODS

UEVs were isolated from the urine of healthy subjects, pre-diabetic, and diabetic patients with varying degrees of kidney damage by ultracentrifugation, and the extracted UEVs were used to measure alpha1-antitrypsin (α1-AT) by Western blot. To explore the function of α1-AT in the inflammatory process leading to DKD, we silenced the expression of α1-AT in renal tubular epithelial cells using cell transfection techniques to assess the differential expression of the inflammatory factors such as MCP-1 and TNF-α using qRT-PCR.

RESULTS

There was no expression of α1-AT in the UEVs of either healthy or pre-diabetic subjects. Its expression was significantly increased in the UEVs of diabetic patients with normoalbuminuria (prior to microalbuminuria), which was more sensitive and more stable than other renal indexes to predict DKD. Additionally, the expression of α1-AT in UEVs was gradually upregulated with the aggravation of DKD and the decline of renal function. In vitro, the mRNA expression of MCP-1 and TNF-α was significantly decreased when the generation of α1-AT in tubular epithelial cells was inhibited under high glucose stimulation.

CONCLUSION

Our results suggest that α1-AT derived from UEVs, especially in diabetic patients with normoalbuminuria, might serve as a potential noninvasive biomarker for diagnosis of DKD early in the development of the disease and may predict the future decline of renal function.

Standard Puerarin Prevents Diabetic Renal Damage by Inhibiting miRNA-140-5p Expression

AIM

This study was designed to use in vivo and in vitro approaches to evaluate puerarin in diabetes-induced renal injury.

MATERIALS AND METHODS

SD rats were divided into NC (normal control), Model (diabetic induced renal injury model), SP-L (model rats treated with low-dose standard puerarin), SP-M (model rats treated with middle-dose standard puerarin), and SP-H (model rats treated with high-dose standard puerarin) groups. We evaluated fasting blood-glucose (FBG), urinary albumin/creatinine ratio (UACR), body weight, and kidney index (KI) in the different groups. TNF-α, IL-1β, and IL-6 concentrations were measured using Elisa assays. HE staining and TUNEL assays were used to evaluate pathology and apoptosis in kidney tissues, respectively. Relative gene and protein expression was measured using RT-qPCR and Western blot assays. Apoptosis was measured using flow cytometry. The correlation between miRNA-145-5p and TLR4 was assessed using dual-luciferase reporter gene assays.

RESULTS

The pathology and apoptosis cell number were deteriorate in Model group; TNF-α, IL-1β and IL-6 concentrations, FGB, UACR and KI were increased and body weight was depressed; meanwhile, relative gene and proteins expressions (miRNA-145-5p, TLR4, MyD88 and NF-κB p65) were significantly different in Model group in vivo and vitro study compared with NC group. SP treatment significantly improved the pathology and apoptosis levels in the tissues, as well as TNF-α, IL-1β and IL-6 concentrations, FGB, UACR, body weight, and KI. In vitro cell studies revealed that SP could prevent renal injury induced by diabetes through the miRNA-145-5p/TLR4 axis.

CONCLUSION

SP prevents diabetes-induced renal damage via miRNA-145-5p overexpression and reduces TLR4/MyD88/NF-κB (p65) pathway activation in vitro and in vivo.

Notch inhibitor mitigates renal ischemia‑reperfusion injury in diabetic rats

Diabetes mellitus can exacerbate renal ischemia-reperfusion (I/R) injury (RI/RI) in diabetic rats. Previous studies have shown that Notch signaling is involved in renal disorders. The aim of the present study was to evaluate the protective effect of the Notch inhibitor γ-secretase N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) on RI/RI in a streptozocin (STZ)-induced diabetic rat model. STZ-induced diabetic rats were randomly grouped for different treatments. Cisplatin was used to trigger the Notch signaling pathway and the animals were preconditioned with DAPT to block the signaling pathway. Renal function, oxidative stress and inflammatory factors were examined. DAPT-treated diabetic rats demonstrated mitigated renal injury and function, antioxidative activity was significantly improved and HIF-1a was upregulated. Notch inhibitor DAPT is a potential therapeutic target to improve the outcome of RI/RI in STZ-induced diabetic rats in part via the regulation of anti-oxidation and HIF-1a.

Investigation of the Mechanism Underlying Calcium Dobesilate-Mediated Improvement of Endothelial Dysfunction and Inflammation Caused by High Glucose

Background/Aims

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease. Calcium dobesilate (CaD) is widely used to treat diabetic retinopathy. Recent studies have demonstrated that CaD exerts protective effects against diabetic nephropathy. The aim of this study was to elucidate the molecular and cellular mechanisms underlying the protective effects of CaD.

Methods

Human umbilical vein endothelial cells (HUVECs) were cultured with different D-glucose concentrations to determine the effects of high glucose on HUVEC gene expression. HUVECs were also incubated with CaD (25 μM, 50 μM, and 100 μM) for 3 days to determine the effects of CaD on HUVEC viability. db/db mice were treated with CaD. 2-[(Aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide (TPCA-1) blocked the nuclear factor-κB (NF-κB) pathway in HUVECs. A pentraxin 3 (PTX3) small interfering RNA (siRNA) intervention experiment was performed in the cells. An adenovirus-encapsulated PTX3 siRNA intervention experiment was performed in db/db mice. Western blot and real-time PCR analyses were used to detect PTX3, p-IKBa/IKBa (I-kappa-B-alpha), and p-eNOS/eNOS (endothelial nitric oxide synthase) expression in mice and HUVECs. Hematoxylin-eosin (HE) staining and periodic acid-Schiff (PAS) staining were used to observe renal tissue damage in mice. PTX3 expression was observed by immunohistochemical staining.

Results

CaD downregulated the expression of PTX3 and p-IKBa/IKBa and upregulated the expression of p-eNOS/eNOS in vitro. When TPCA-1 was used, high glucose induced high PTX3 expression, and the expression of p-eNOS/eNOS increased. After PTX3 gene silencing, the expression of p-eNOS/eNOS also increased. In vivo, CaD reduced the expression of PTX3 and p-IKBa/IKBa in the kidneys of db/db mice and increased the expression of p-eNOS/eNOS. After PTX3 gene silencing, the urine protein and renal function of db/db mice were ameliorated, the glomerular extracellular matrix was decreased, and the expression of p-eNOS/eNOS was increased.

Conclusions

Our results suggested that CaD may inhibit the expression of PTX3 by altering the IKK/IKB/NF-κB pathway, thereby improving endothelial dysfunction in HUVECs. PTX3 may be a potential therapeutic target for DKD.

Human mesenchymal stromal cells broadly modulate high glucose-induced inflammatory responses of renal proximal tubular cell monolayers

BACKGROUND

Renal proximal tubular epithelial cells (RPTEC) are dysfunctional in diabetic kidney disease (DKD). Mesenchymal stromal cells (MSC) may modulate DKD pathogenesis through anti-inflammatory mediators. This study aimed to investigate the pro-inflammatory effect of extended exposure to high glucose (HG) concentration on stable RPTEC monolayers and the influence of MSC on this response.

METHODS

Morphologically stable human RPTEC/TERT1 cell monolayers were exposed to 5 mM and 30 mM (HG) D-glucose or to 5 mM D-glucose + 25 mM D-mannitol (MAN) for 5 days with sequential immunoassays of supernatants and end-point transcriptomic analysis by RNA sequencing. Under the same conditions, MSC-conditioned media (MSC-CM) or MSC-containing transwells were added for days 4-5. Effects of CM from HG- and MAN-exposed RPTEC/MSC co-cultures on cytokine secretion by monocyte-derived macrophages were determined.

RESULTS

After 72-80 h, HG resulted in increased RPTEC/TERT1 release of interleukin (IL)-6, IL-8, monocyte chemoattractant protein (MCP)-1 and neutrophil gelatinase-associated lipocalin (NGAL). The HG pro-inflammatory effect was attenuated by concentrated (10×) MSC-CM and, to a greater extent, by MSC transwell co-culture. Bioinformatics analysis of RNA sequencing data confirmed a predominant effect of HG on inflammation-related mediators and biological processes/KEGG pathways in RPTEC/TERT1 stable monolayers as well as the non-contact-dependent anti-inflammatory effect of MSC. Finally, CM from HG-exposed RPTEC/MSC transwell co-cultures was associated with attenuated secretion of inflammatory mediators by macrophages compared to CM from HG-stimulated RPTEC alone.

CONCLUSIONS

Stable RPTEC monolayers demonstrate delayed pro-inflammatory response to HG that is attenuated by close proximity to human MSC. In DKD, this MSC effect has potential to modulate hyperglycemia-associated RPTEC/macrophage cross-talk.

Correlations between serum inflammatory markers and comorbidities in patients with end-stage renal disease

Objectives

Chronic inflammatory processes are common in patients with renal disease, especially those with end-stage renal disease (ESRD), in whom inflammatory markers have been shown to increase with renal function deterioration. ESRD is usually accompanied by other chronic diseases such as hypertension and diabetes. The relationships between ESRD comorbidities and serum levels of inflammatory markers have not yet been fully understood. The aim of this study was to assess serum levels of inflammatory markers in different ESRD cohorts and to investigate the correlations between these inflammatory markers and disease comorbidities.

Methods

A total of 147 patients were grouped according to their comorbid conditions: diabetic only, hypertensive only, diabetic and hypertensive, and neither diabetic nor hypertensive. Serum levels of C-reactive protein (CRP), tumour necrosis factor-alpha (TNF-α), and interleukin-1-beta (IL-1β) were investigated in different ESRD cohorts by enzyme-linked immunosorbent assay.

Results

Serum CRP and TNF-α levels were high in diabetic patients (p = 0.0001), hypertensive patients (p = 0.0001), and those who had both diseases (p = 0.0001), when compared to ESRD patients without these comorbidities. There was no significant change in serum IL-1β levels between patients with diabetes mellitus and/or hypertension compared to patients who did not have these diseases.

Conclusions

Our results showed that, in ESRD patients, CRP and TNF-α seem to be largely affected by patients’ comorbidities, unlike IL-1β, which might be affected more by the dialysis process even in the absence of comorbidities.

Hydrogen Sulfide: Recent Progression and Perspectives for the Treatment of Diabetic Nephropathy

Diabetic kidney disease develops in approximately 40% of diabetic patients and is a major cause of chronic kidney diseases (CKD) and end stage kidney disease (ESKD) worldwide. Hydrogen sulfide (H₂S), the third gasotransmitter after nitric oxide (NO) and carbon monoxide (CO), is synthesized in nearly all organs, including the kidney. Though studies on H₂S regulation of renal physiology and pathophysiology are still in its infancy, emerging evidence shows that H₂S production by renal cells is reduced under disease states and H₂S donors ameliorate kidney injury. Specifically, aberrant H₂S level is implicated in various renal pathological conditions including diabetic nephropathy. This review presents the roles of H₂S in diabetic renal disease and the underlying mechanisms for the protective effects of H₂S against diabetic renal damage. H₂S may serve as fundamental strategies to treat diabetic kidney disease. These H₂S treatment modalities include precursors for H₂S synthesis, H₂S donors, and natural plant-derived compounds. Despite accumulating evidence from experimental studies suggests the potential role of the H₂S signaling pathway in the treatment of diabetic nephropathy, these results need further clinical translation. Expanding understanding of H₂S in the kidney may be vital to translate H₂S to be a novel therapy for diabetic renal disease.

Expression levels of serum vasohibin-1 and other biomarkers in type 2 diabetes mellitus patients with different urinary albumin to creatinine ratios

AIM

To determine the serum levels of vasohibin (VASH)-1 and other biomarkers in type 2 diabetes mellitus (T2DM) patients with different urinary albumin to creatinine ratios (UACR), and correlate VASH-1 expression with the inflammation and fibrosis in diabetic kidney disease (DKD).

METHODS

A total of 697 T2DM patients were stratified into four groups: N-UAlb (UACR <30 mg/g with normal blood pressure, n = 144), M-UAlb (UACR 30-300 mg/g with normal blood pressure, n = 143), L-UAlb (UACR >300 mg/g with normal blood pressure, n = 126), and L-UAlb+HP (UACR >300 mg/g with hypertension, n = 134). In addition, 150 healthy subjects were included as normal controls (NC). In addition to recording the age and duration of diabetes, the serum levels of VASH-1, silent information regulator factor 2-related enzyme 1 (sirtuin-1, SIRT1), hypoxia inducible factor 1α (HIF1α), vascular endothelial growth factor (VEGF), C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), and the erythrocyte sedimentation rate (ESR) were measured. Clinical parameters related to UACR and VASH-1 were analyzed by one-way ANOVA, Pearson correlation and ridge regression analysis.

RESULTS

The UACR, VASH-1, glycosylated hemoglobin (HbA1c), ESR, CRP, VEGF, HIF1α, TNF-α and TGF-β1 levels in all patient groups were significantly higher, and SIRT1 levels were lower compared to the NC group. Pearson correlation analysis showed that UACR and VASH-1 levels were positively correlated with HbA1c, ESR, CRP, VEGF, HIF1α, TNF-α and TGF-β1, and negatively with SIRT1. Ridge regression analysis showed that every serological marker was an independent factor affecting UACR.

CONCLUSION

Serum VASH-1 may be associated with the expression of renal inflammation and fibrosis-related factors, and have a potential connection with DKD.

Long noncoding RNA: an emerging player in diabetes and diabetic kidney disease

Diabetic kidney disease (DKD) is among the most common complications of diabetes mellitus (DM), and remains the leading cause of end-stage renal diseases (ESRDs) in developed countries, with no definitive therapy yet available. It is imperative to decipher the exact mechanisms underlying DKD and identify novel therapeutic targets. Burgeoning evidence indicates that long non-coding RNAs (lncRNAs) are essential for diverse biological processes. However, their roles and the mechanisms of action remain to be defined in disease conditions like diabetes and DKD. The pathogenesis of DKD is twofold, so is the principle of treatments. As the underlying disease, diabetes per se is the root cause of DKD and thus a primary focus of therapy. Meanwhile, aberrant molecular signaling in kidney parenchymal cells and inflammatory cells may directly contribute to DKD. Evidence suggests that a number of lncRNAs are centrally involved in development and progression of DKD either via direct pathogenic roles or as indirect mediators of some nephropathic pathways, like TGF-β1, NF-κB, STAT3 and GSK-3β signaling. Some lncRNAs are thus likely to serve as biomarkers for early diagnosis or prognosis of DKD or as therapeutic targets for slowing progression or even inducing regression of established DKD. Here, we elaborated the latest evidence in support of lncRNAs as a key player in DKD. In an attempt to strengthen our understanding of the pathogenesis of DKD, and to envisage novel therapeutic strategies based on targeting lncRNAs, we also delineated the potential mechanisms of action as well as the efficacy of targeting lncRNA in preclinical models of DKD.