Valsartan Mitigates the Progression of Methotrexate-Induced Acute Kidney Injury in Rats via the Attenuation of Renal Inflammation and Oxidative Stress

Background

Methotrexate (MTX) is a folic acid antagonist, commonly administered for the treatment of a variety of cancers. However, methotrexate toxicity including bone marrow suppression and hepatic and renal toxicity limits its use. Angiotensin AT1 receptor blockers including Valsartan (Val) possess the ability to ameliorate MTX-induced toxicity through various mechanisms. In this study, we explored the potential reno-protective effects of Val against MTX-induced acute kidney injury in rats.

Methods

Twenty-four Wistar rats were randomly segregated into 3 groups. Group 1 served as the control group and received an oral dose of 1mL/kg of normal saline. Group 2 received a single dose of 20 mg/kg of MTX intraperitoneally (IP) for 5 days. Group 3 received a single IP dose of 20 mg/kg of MTX followed by an oral dose of 10 mg/kg of Valsartan for 5 days. At the end of the experiment, the levels of serum kidney biomarkers, inflammatory and oxidative stress markers were accessed. Furthermore, the effect of MTX on kidney tissue histology was examined.

Results and discussion

Our results showed that MTX treatment increased the level of serum kidney and inflammatory biomarkers and decreased the level of antioxidants SOD and GSH while increasing the lipid peroxidation contents. Furthermore, MTX treatment caused structural changes to kidney histology. However, the administration of Val significantly prevented these changes.

Conclusion

Valsartan possesses nephroprotective potential and might serve as a potential therapeutic strategy against MTX-induced kidney injury.

Plausible prediction of renoprotective effects of sodium-glucose cotransporter-2 inhibitors in patients with chronic kidney diseases

This narrative review was conducted due to uncertainty in predicting the beneficial impact of sodium-glucose cotransporter-2 (SGLT2) inhibitors on a dip of estimated glomerular filtration rate (eGFR), regardless of albuminuria presence, with the aim of elucidating plausible predictors of kidney function outcome among patients treated with SGLT2 inhibitors. The PubMed and Web of Science databases were searched in May 2023 for relevant articles published in English between 2013 and 2023. A total of 25 full-length scientific publications (comprising 11 large randomized trials and two cohort studies) were included for analysis. The majority of studies demonstrated a limited value of conventional biomarkers, such as initial decline in eGFR, a trajectory of eGFR during SGLT2 inhibitor administration, and urine albumin-to-creatinine ratio (UACR), in prediction of renoprotection. Included studies showed that the tendency to decreased eGFR, UACR, hemoglobin, glycosylated hemoglobin, lipid profile, serum uric acid, inflammatory biomarkers and natriuretic peptides did not predict clinical outcomes in groups without heart failure (HF) treated with SGLT2 inhibitors. In HF groups, biomarkers of inflammation, kidney injury, oxidative stress, mitochondrial dysfunction, ketogenesis, energy metabolism, and adipose tissue dysfunction (adropin and irisin), were detected with the aim of finding potential biomarkers. Biomarkers of adipose tissue dysfunction and inflammation may be promising for predicting SGLT2 inhibitor benefit compared with N-terminal pro-B-type natriuretic peptide and energy metabolism indicators.

Potential renoprotective effect of SGLT2 inhibitors against contrast-induced AKI in diabetic STEMI patients undergoing primary PCI

BACKGROUND

It has been demonstrated that there is a significant reduction in the incidence of cardiovascular events, mortality rates, and worsening kidney disease in patients using sodium-glucose cotransporter 2 inhibitors (SGLT2i). However, there is limited information about the effect of SGLT2i on the incidence of contrast-induced acute kidney injury (CI-AKI) in patients undergoing primary percutaneous intervention (pPCI).

AIMS

Our research was focused on examining how SGLT2i exposure impacts CI-AKI occurrence in patients with ST-segment elevation myocardial infarction (STEMI) and undergoing pPCI.

RESULTS

This retrospective, single-center, case-control study included diabetic patients diagnosed with STEMI who underwent pPCI in a tertiary healthcare center between 2021 and 2022. The study population included SGLT2i users (n = 130) and non-SGLT2i users (n = 165). Inverse probability propensity score weighting and doubly robust estimation were performed to decrease bias and to balance covariate distribution for estimating average treatment for those treated. In a doubly robust inverse probability weighted regression model, in which covariates were balanced, CI-AKI risk was also found to be lower in the SGLT2i-user group (OR: 0.86 [0.76-0.98]; 95% CI; P = 0.028). In addition, ejection fraction, admission creatinine, albumin, and volume of contrast media were found to be independent predictors of CI-AKI in patients presenting with STEMI and undergoing pPCI.

CONCLUSION

Our study provides evidence supporting the potential protective effect of SGLT2i against CI-AKI in diabetic patients presenting with STEMI and undergoing pPCI.

Evaluation of Effect of Montelukast in the Model of Streptozotocin Induced Diabetic Nephropathy in Rats

Background

Diabetic nephropathy is a progressive condition and a leading cause of end-stage renal disease. Oxidative stress and inflammation play an important role in its pathogenesis. In pre-clinical studies, Montelukast had shown renoprotective and anti-oxidant properties, hence the study was planned to evaluate the effect of Montelukast in a Streptozotocin (STZ) induced model of diabetic nephropathy.

Methods

40 Wistar rats of either sex were randomly divided into four groups viz. 1. Vehicle control group, 2. Enalapril (5 mg/kg), 3. Montelukast low-dose (10 mg/kg) and 4. High-dose (20 mg/kg) group. On day 1, diabetes was induced using a single dose of STZ (60 mg/kg) intraperitoneally. Diabetes induction was verified based on fasting blood glucose (FBG) levels on day 7 and from day 8 to day 42, rats were given study drugs. FBG, serum creatinine, blood urea nitrogen (BUN) and urine microalbumin levels were assessed pre-study and post-study. Assessments of kidney malondialdehyde (MDA), reduced glutathione (GSH) and renal histopathology were carried out at the end of the study.

Results

Montelukast 10 mg/kg group showed significantly lower urine microalbumin levels compared to the vehicle control group (p < 0.05). Montelukast 20 mg/kg group showed significantly lower levels of FBG, serum creatinine, BUN and urine microalbumin compared to the vehicle control group (p < 0.05). In addition, Montelukast 20 mg/kg group also showed better effects on kidney MDA and GSH levels (p < 0.05) and histopathological scores compared to the vehicle control group.

Conclusion

Montelukast showed a protective effect in the model of diabetic nephropathy because of its antioxidant effect.

Murine Malaria Model: Ketoconazole Prevented Malaria while Proguanil and Sulfadoxine/Pyrimethamine Protected against Malaria-associated Anemia and Kidney Damage

BACKGROUND

The concern about the global spread of resistant malaria has made the researchers not focus only on the treatment of established infections but relatively more on the prevention of the disease.

OBJECTIVE

This study evaluates the chemopreventive activity of ketoconazole in a murine malarial model.

METHOD

Five out of seven groups of mice were pretreated for five days with proguanil (PRG), sulfadoxine/ pyrimethamine (SP), 10, 20, and 40 mg/kg body weight (b.w) of ketoconazole (KET10, KET20, and KET40), before being infected (on the sixth day) with Plasmodium berghei. Two other groups were infected-not-treated (INT) and not-infected-nor-treated (NINT). At 72 hours postinfection, five out of ten mice in each group were sacrificed to assess parasitemia, chemoprevention, hematologic, hepatic, and renal parameters. The remaining mice were observed for 28 days to determine their mean survival day post-infection (SDPI).

RESULTS

All ketoconazole groups, except KET10, demonstrated 100% chemoprevention and significantly higher mean SDPI (p<0.001) in relation to INT (negative control). There was no significant difference in the mean SDPI observed in KET20 in relation to PRG or NINT (healthy control). A dose-related increase (p<0.01) in the mean plasma urea was observed when ketoconazole groups were compared to one another: KET10 versus KET20 (p<0.01) and KET20 versus KET40 (p<0.01). Sulfadoxine/pyrimethamine demonstrated significantly reduced mean plasma urea (p<0.001) and creatinine (p<0.05) in relation to INT and NINT, respectively. While PRG demonstrated significantly higher mean red blood cell (RBC), hemoglobin (HGB), and hematocrit (HCT) in relation to INT.

CONCLUSION

Ketoconazole possesses prophylactic antimalarial activity with associated dose-related renal impairment. Sulfadoxine/pyrimethamine demonstrated renoprotective potentials, while PRG prevented malaria-associated anemia.

Sirtuin 3 is required for the dexmedetomidine-mediated alleviation of inflammation and oxidative stress in nephritis

INTRODUCTION

Although sirtuin 3 (SIRT3) is known to be involved in dexmedetomidine (DEX)-mediated alleviation of renal ischemia and reperfusion injury, the influence of the association between DEX and SIRT3 on nephritis development remains unclear. In this study, the role of SIRT3 in DEX-mediated amelioration of inflammation and oxidative stress in nephritis as well as the possible underlying mechanism were explored in vivo and in vitro.

METHODS

An animal model of glomerulonephritis was generated by injecting mice with interferon-alpha (IFNα)-expressing adenoviruses, and periodic acid-Schiff staining was then used to reveal pathogenicity-related changes in the renal tissue. Additionally, human embryonic kidney cells (HEK293) and renal mesangial cells (RMCs) were treated with IFNα to establish cell models of inflammation in vitro.

RESULTS

DEX administration alleviated glomerulonephritis in the animal model and upregulated SIRT3 expression in the renal tissue. SIRT3 knockdown inhibited the renoprotective effects of DEX against nephritis. IFNα induced inflammation, oxidative stress, and apoptosis in the RMCs and HEK293 cells and reduced their growth, as evidenced by the evaluation of cytokine levels (enzyme-linked immunosorbent assay), reactive oxygen species generation, catalase and superoxide dismutase activities, nuclear factor-erythroid factor 2-related factor 2/heme oxygenase-1 signal transduction, apoptotic cell proportion, and cell viability. In addition to promoting SIRT3 expression, DEX inhibited IFNα-induced inflammation, oxidative stress, and apoptosis in these cells and promoted their viability. SIRT3 knockdown partially reversed the beneficial effects of DEX on RMCs and HEK293 cells.

CONCLUSIONS

Our results suggest that DEX exhibits renoprotective activity during nephritis progression, protecting renal cells against inflammatory injury by promoting SIRT3 expression.

Cardamonin mitigates kidney injury by modulating inflammation, oxidative stress, and apoptotic signaling in rats subjected to renal ischemia and reperfusion

Renal ischemia-reperfusion injury (IRI) is a critical health concern that aggravates the pathophysiology of acute kidney injury (AKI), leading to high mortality rates in intensive care units. Cardamonin is a natural compound with anti-inflammatory and antioxidant properties. The current study aimed to evaluate the renoprotective impact of cardamonin against AKI induced by renal IRI. Male rats (n=5 per group) were divided into four groups: the sham group underwent anesthesia and abdominal incision only; the control group experienced bilateral renal artery clamping for 30 minutes followed by 2 hours of reperfusion; the vehicle group received the cardamonin vehicle 30 minutes before ischemia induction; and the cardamonin group was administered 5 mg/kg of cardamonin 30 minutes before ischemia. Blood urea nitrogen (BUN) and creatinine were measured to assess the renal function. Tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), interleukin-6 (IL-6), caspase 3, and F2-isoprostane were assessed in renal tissues. Kidney injury was examined using the hematoxylin and eosin stain method. Compared to the sham group, the control group exhibited significantly higher levels of BUN, creatinine, TNF-α, IL-1β, IL-6, F2-isoprostane, and caspase 3 in renal tissues, along with severe kidney injury as evidenced by histological analysis. Compared to the control group, pretreatment with cardamonin resulted in a significant reduction in these biomarkers and alleviated renal damage. Cardamonin had renoprotective effects against renal ischemia and reperfusion injury via modulating inflammation, oxidative stress, and apoptosis pathways.

Exploring the Cardiovascular Benefits of Sodium-Glucose Cotransporter-2 (SGLT2) Inhibitors: Expanding Horizons Beyond Diabetes Management

Globally, cardiovascular disease (CVD) continues to be the primary cause of morbidity and mortality. The risk of cardiovascular disease is markedly increased in individuals with type 2 diabetes mellitus (T2DM), making managing cardiovascular health a top priority. Initially developed for their glucose-lowering properties, sodium-glucose cotransporter 2 (SGLT2) inhibitors have emerged as a transformative class of pharmaceuticals with profound cardiovascular benefits that extend far beyond glycemic control. One of the most striking findings is the substantial reduction in major adverse cardiovascular events (MACE), including myocardial infarction, stroke, and cardiovascular mortality, observed in clinical trials evaluating SGLT2 inhibitors. These extraordinary cardioprotective effects are demonstrated by landmark trials such as EMPA-REG OUTCOME, CANVAS, and DECLARE-TIMI 58, which are discussed in detail. In addition, SGLT2 inhibitors have demonstrated positive outcomes in heart failure (HF) with reduced ejection fraction, which has led to their incorporation into HF treatment guidelines. SGLT2 inhibitors offer renoprotection by delaying the progression of diabetic kidney disease, reducing albuminuria, preserving glomerular filtration rates, and their immediate cardiovascular benefits. We investigate the potential mechanisms underlying these renal benefits, focusing on the role of hemodynamic alterations and intraglomerular pressure reduction. In addition, SGLT2 inhibitors have a distinct diuretic effect that can contribute to volume reduction and symptom alleviation in patients with heart failure (HF). This diuretic action, distinct from conventional diuretics, warrants additional research to optimize their use in T2DM and HF patients. The risk of euglycemic diabetic ketoacidosis, genital mycobacterial infections, and bone fractures are also discussed. Understanding these issues is essential for making educated clinical decisions. In conclusion, SGLT2 inhibitors have transcended their initial function as anti-diabetic agents to become essential components of cardiovascular and renal protection strategies in T2DM patients. Their diverse benefits, which include cardioprotection, renoprotection, and the potential for HF management, highlight their potential to transform cardiovascular medicine. Optimizing the use of SGLT2 inhibitors in clinical practice bears the promise of improved cardiovascular outcomes for patients with T2DM and beyond as we navigate this changing landscape.

Clinical Prospect of Mesenchymal Stromal/Stem Cell-Derived Extracellular Vesicles in Kidney Disease: Challenges and the Way Forward

Kidney disease is a growing public health problem worldwide, including both acute and chronic forms. Existing therapies for kidney disease target various pathogenic mechanisms; however, these therapies only slow down the progression of the disease rather than offering a cure. One of the potential and emerging approaches for the treatment of kidney disease is mesenchymal stromal/stem cell (MSC) therapy, shown to have beneficial effects in preclinical studies. In addition, extracellular vesicles (EVs) released by MSCs became a potent cell-free therapy option in various preclinical models of kidney disease due to their regenerative, anti-inflammatory, and immunomodulatory properties. However, there are scarce clinical data available regarding the use of MSC-EVs in kidney pathologies. This review article provides an outline of the renoprotective effects of MSC-EVs in different preclinical models of kidney disease. It offers a comprehensive analysis of possible mechanisms of action of MSC-EVs with an emphasis on kidney disease. Finally, on the journey toward the implementation of MSC-EVs into clinical practice, we highlight the need to establish standardized methods for the characterization of an EV-based product and investigate the adequate dosing, safety, and efficacy of MSC-EVs application, as well as the development of suitable potency assays.

Role of p38 MAPK, Akt and NFκB in renoprotective effects of nebivolol on renal ischemia-reperfusion injury in rats

Renal ischemia-reperfusion (I-R) injury is a complex pathophysiologic condition characterized by oxidative stress, inflammation and apoptosis. We investigated the potential renoprotective effect of nebivolol, a β₁ adrenergic receptor blocker, against renal I-R injury. We focused on the role of nebivolol in activating p38 mitogen-activated protein kinase (MAPK) signaling, Akt (protein kinase B) and nuclear factor-κB (NFκB) transcription factors, which contribute to oxidative stress, inflammation and apoptosis during renal I-R. We divided 20 adult male Wistar albino rats into three experimental groups. Group 1 was a sham control in which only laparotomy was performed. Group 2 was the I-R group in which both kidneys were made ischemic for 45 min, then reperfused for 24 h. Group 3 was the I-R + nebivolol group in which 10 mg/kg nebivolol was administrated by gavage for 7 days before I-R. We measured Inflammation, oxidative stress and active caspase-3 as well as activation of p38 MAPK, Akt (protein kinase B) and NFκB transcription factor. Nebivolol significantly reduced oxidative stress and increased superoxide dismutase levels during renal I-R. We found that nebivolol significantly decreased interstitial inflammation, and TNF-α and interleukin-1β mRNA expression. Nebivolol significantly reduced active caspase-3 and kidney injury molecule-1 (KIM-1) expressions. Nebivolol also significantly decreased activation of p38 MAPK signaling and NFκB, and induced Akt activation during renal I-R. Our findings suggest that nebivolol may be useful for management of renal I-R injury.

Dose- and time-dependent renoprotection of Angelica sinensis in patients with chronic kidney disease: A longitudinal cohort study

Background: Based on their anti-oxidative and anti-fibrotic properties, Angelica sinensis (Oliv.) Diels roots [Apiaceae; Radix Angelicae sinensis] (Danggui [abbreviated as S in the context]), Astragalus membranaceus (Fisch.) Bunge [Fabaceae; Astragalus membranaceus] (Huangqi [A]), Rheum palmatum L. [Polygonaceae; Rheum palmatum] (Dahuang [R]), and Salvia miltiorrhiza Bunge [Lamiaceae; Salvia miltiorrhiza Bunge radix et rhizoma] (Danshen [D]) are potential renoprotective Chinese herbal medicines (CHMs). Renoprotection using ARD alone for the treatment of chronic kidney disease (CKD) has been documented in pre-clinical, clinical, and meta-analysis research; however, only pre-clinical data are available for the use of S alone. Moreover, with an increasing number of CKD patients taking prescribed CHMs, hyperkalemia risk remains unclear. Methods: This study retrospectively analyzed national health insurance claims data in 2001-2017. Propensity score matching was used to analyze renal and survival outcomes and the dose-response effects of S without ARD use in 18,348 new S users, 9,174 new ARD users, and 36,696 non-users. Cox proportional hazard regression was used to investigate adjusted hazard ratios (aHRs) for end-stage renal disease (ESRD) in the presence of competing mortality and death. The additive effect of the S herb in single form to compounds was also analyzed. Additionally, to analyze hyperkalemia risk, an exact match on each covariate was used to include 42,265 new CHM users and non-users, while Poisson regression was used to estimate adjusted incidence rate ratios (aIRRs) of hyperkalemia of prescribed CHMs. Results: S users and ARD users were associated with aHRs of 0.77 (95% confidence interval; 0.69-0.86) and 1.04 (0.91-1.19), respectively, for ESRD and 0.55 (0.53-0.57) and 0.71 (0.67-0.75), respectively, for death. The renal and survival benefits of S use were consistent in several sensitivity analyses. The dose- and time-dependent renoprotection and dose-dependent survival benefits were observed for S use. The top two additive renoprotective collocations of the S herb in compounds were Xue-Fu-Zhu-Yu-Tang and Shen-Tong-Zhu-Yu-Tang, followed by Shu-Jing-Huo-Xue-Tang and Shen-Tong-Zhu-Yu-Tang. Moreover, CHM users were associated with aIRRs of 0.34 (0.31-0.37) for hyperkalemia. Conclusion: This study suggests dose- and time-dependent renoprotection and dose-dependent survival benefits of the S herb in compounds and no increased hyperkalemia risk of the prescribed CHMs in CKD patients.

The postprandial actions of GLP-1 receptor agonists: The missing link for cardiovascular and kidney protection in type 2 diabetes

Recent clinical trials in people with type 2 diabetes have demonstrated beneficial actions on heart and kidney outcomes following treatment with GLP-1RAs. In part, these actions are consistent with improved glucose control and significant weight loss. But GLP-1RAs may also have additive benefits by improving postprandial dysmetabolism. In diabetes, dysregulated postprandial nutrient excursions trigger inflammation, oxidative stress, endothelial dysfunction, thrombogenicity, and endotoxemia; alter hormone levels; and modulate cardiac output and regional blood and lymphatic flow. In this perspective, we explore the actions of GLP-1RAs on the postprandial state and their potential role in end-organ benefits observed in recent trials.

Renoprotection of Microcystin-RR in Unilateral Ureteral Obstruction-Induced Renal Fibrosis: Targeting the PKM2-HIF-1α Pathway

Renal fibrosis is a pathological characteristic of the endpoint of chronic kidney disease (CKD), which remains a major public health problem. None of the current therapies is effective in stopping kidney fibrosis progression. In light of our novel detection of a potential antifibrosis of microcystins (MCs), we investigate the renoprotection effect of MCs with UUO-induced renal fibrosis. The treatment of MCs was initiated in model animals in advance of UUO operation. After determining that the antifibrotic effect of MCs was independent of its toxicity, our study focused on the renoprotection of microcystin-RR (MC-RR), a lower toxic congener of MCs, in UUO mice and the cell models in vitro. The co-immunoprecipitation assay and recombination plasmid transfection were used in the investigation of the mechanism of antifibrosis of MC-RR. The data show that MC-RR substantially exerts an effect on renoprotection with suppression of the expression of TGF-β1/Smad signaling molecules and a blockage in epithelial dedifferentiation and myofibroblast activation in UUO model animals. MC-RR shows a binding directly to pyruvate kinase M2 (PKM2), downregulates PKM2-HIF-1α signaling, restores the inhibited expression of MMP-7 and MMP-13, and reduces the upregulated expression of MMP-9 in UUO renal tissues. The current study demonstrates a novel effect of MC-RR on renoprotection in kidney damage, which could be conducted in therapeutics for chronic kidney disease.

Recent advances in the pharmacotherapeutic management of diabetic kidney disease

INTRODUCTION

Diabetic kidney disease (DKD) remains a major cause of morbidity and mortality in diabetes and is a key cause of end-stage kidney disease (ESKD) worldwide. Major clinical advances have been confirmed in large trials demonstrating renoprotection, adding to the benefits of existing intensive glucose and blood pressure control therapies. Furthermore, there are exciting new treatments predominantly at an experimental and early clinical phase which appear promising.

AREAS COVERED

The authors review DKD in the context of existing and emerging therapies affording cardiorenal benefits including SGLT2 inhibitors and GLP-1 receptor agonists. They explore novel therapies demonstrating potential including a newly developed mineralocorticoid receptor antagonist and endothelin receptor blockade, while evaluating the utility of DPP4 inhibitors in current clinical practice. They also consider the recent evidence of emerging therapies targeting metabolic pathways with enzyme inhibitors, anti-fibrotic agents, and agents modulating transcription factors.

EXPERT OPINION

Significant improvements have been made in the management of DKD with SGLT2i and GLP-1 agonists providing impressive renoprotection, with novel progress in renin-angiotensin-aldosterone system (RAAS) blockade with finerenone. There is also great potential for several new experimental therapies. These advances provide us with optimism that the outlook of this devastating condition will continue to improve.

Extracellular Vesicles and Acute Kidney Injury: Potential Therapeutic Avenue for Renal Repair and Regeneration

Acute kidney injury (AKI) is a sudden decline of renal function and represents a global clinical problem due to an elevated morbidity and mortality. Despite many efforts, currently there are no treatments to halt this devastating condition. Extracellular vesicles (EVs) are nanoparticles secreted by various cell types in both physiological and pathological conditions. EVs can arise from distinct parts of the kidney and can mediate intercellular communication between various cell types along the nephron. Besides their potential as diagnostic tools, EVs have been proposed as powerful new tools for regenerative medicine and have been broadly studied as therapeutic mediators in different models of experimental AKI. In this review, we present an overview of the basic features and biological relevance of EVs, with an emphasis on their functional role in cell-to-cell communication in the kidney. We explore versatile roles of EVs in crucial pathophysiological mechanisms contributing to AKI and give a detailed description of the renoprotective effects of EVs from different origins in AKI. Finally, we explain known mechanisms of action of EVs in AKI and provide an outlook on the potential clinical translation of EVs in the setting of AKI.

Renoprotective effect of vinpocetine against ischemia/reperfusion injury: Modulation of NADPH oxidase/Nrf2, IKKβ/NF-κB p65, and cleaved caspase-3 expressions

Ischemia/reperfusion injury (IRI) during kidney transplantation is a serious clinical problem with a high mortality rate and a lack of therapy. Therefore, there is a need to improve the ability of the kidney to tolerate IRI during transplantation. This study aimed to investigate the possible protective effect of vinpocetine; a derivative of vincamine alkaloid; against renal IRI in rats with the elucidation of the involved mechanisms. Vinpocetine (25 mg/kg; i.p.) was administered for 10 successive days before the induction of ischemia by bilateral clamping of both renal pedicles for 45 min followed by 24 h of reperfusion. Blood and renal tissue samples were then collected for biochemical, molecular, and histopathological investigations. Vinpocetine significantly reduced serum creatinine and blood urea nitrogen levels in rats subjected to IRI. It also reduced mRNA expression of NADPH oxidase and renal content of malondialdehyde, while enhanced Nrf2 protein expression and renal content of reduced glutathione. The suppression of the provoked inflammatory response was evident by the downregulation of IKKβ and NF-κB p65 protein expressions, as well as their downstream inflammatory markers; tumor necrosis factor-α, interleukin-6, and myeloperoxidase. In addition, vinpocetine reduced protein expression of the apoptotic executioner cleaved caspase-3. These nephroprotective effects were confirmed by the improvement in histopathological features. Collectively, the protective effect of vinpocetine against IRI could be attributed to modulation of NADPH oxidase/Nrf2, IKKβ/NF-κB p65, and cleaved caspase-3 expressions. Thus, vinpocetine could improve oxidant/antioxidant balance, suppress triggered inflammatory response, and promote renal cell survival after IRI.

Serum bilirubin as a predictor of graft outcomes after renal transplant

Bilirubin is a signaling molecule that alters the immune response and metabolism. While bilirubin has been employed as a marker of renal and cardiovascular health, its role in renal transplant recipients is not known. In this study, we sought to determine the impact of bilirubin (total, direct and indirect) on the estimated glomerular filtration rate (eGFR) after renal transplantation. We conducted a retrospective review of pre- and postoperative bilirubin levels in 457 renal transplant recipients at a single center. Pre- and post-rejection bilirubin levels were also assessed in those patients who experienced a rejection episode. No statistically significant differences were found in bilirubin levels during the pre-transplant to post-rejection period among patients who experienced rejection with kidney allograft survival. No statistically significant associations were observed between baseline bilirubin and post-transplant eGFR in the full patient group or within the gender- or race-stratified groups. Baseline bilirubin was not correlated with time to rejection. Our results suggest that bilirubin may not offer renoprotection in renal transplant recipients.

Expert opinion on the cooperation of diabetologists and internists with nephrologists in the care of patients with chronic kidney diseases

Chronic kidney disease (CKD) affects 10% of the population of developed countries and significantly affects the population health. In addition to the well-known renoprotection tools slowing down the progression of CKD, SGLT2 inhibitors have been newly introduced into clinical practice based on the results of extensive studies, both in diabetics and non-diabetics. This expert opinion discusses the classification of CKD, current renoprotection options, and the recent role of SGLT2 inhibitors in the care of patients with CKD.

Huangjinsan ameliorates adenine-induced chronic kidney disease by regulating metabolic profiling

Chronic kidney disease is an increasingly serious public health problem worldwide. Our recent studies have shown that Huangjinsan has a renal protective effect on chronic kidney disease, but the specific mechanism by which this effect occurs is not clear. To study the therapeutic effect of Huangjinsan on chronic kidney disease and to explore its possible mechanism of action through nontargeted metabolomics methods, a chronic kidney disease rat model was induced by adenine, and the Huangjinsan extract was given by oral gavage. Body weight, the kidney index, pathological sections, and a series of biochemical indicators were measured. High-performance liquid chromatography quadrupole time-of-flight mass spectrometry was used to analyze the changes in the plasma metabolome. Huangjinsan significantly reduced indicators of kidney damage, including total protein, albumin, the total protein to creatinine ratio, and the albumin to creatinine ratio in urine, as well as IL-2, MCP-1α, and blood urea levels in plasma. Based on nontargeted metabolomics, 13 metabolites related to chronic kidney disease were discovered. These metabolites are closely related to glycerophospholipid metabolism, arginine and proline metabolism, and sphingolipid metabolism. We found that Huangjinsan can restore the renal function of adenine-induced chronic kidney disease by regulating the metabolic profile.

Role of microRNAs in Obesity-Related Kidney Disease

Obesity is a major global health problem and is associated with a significant risk of renal function decline. Obesity-related nephropathy, as one of the complications of obesity, is characterized by a structural and functional damage of the kidney and represents one of the important contributors to the morbidity and mortality worldwide. Despite increasing data linking hyperlipidemia and lipotoxicity to kidney injury, the apprehension of molecular mechanisms leading to a development of kidney damage is scarce. MicroRNAs (miRNAs) are endogenously produced small noncoding RNA molecules with an important function in post-transcriptional regulation of gene expression. miRNAs have been demonstrated to be important regulators of a vast array of physiological and pathological processes in many organs, kidney being one of them. In this review, we present an overview of miRNAs, focusing on their functional role in the pathogenesis of obesity-associated renal pathologies. We explain novel findings regarding miRNA-mediated signaling in obesity-related nephropathies and highlight advantages and future perspectives of the therapeutic application of miRNAs in renal diseases.

Renoprotection with sodium-glucose cotransporter-2 inhibitors in children: Known and unknown

Sodium-glucose cotransporter-2 (SGLT2) inhibitors represent novel hypoglycemic drugs for the treatment of adult diabetes that have shown considerable potential for cardioprotection and renoprotection. This new drug can inhibit SGLT2 at the proximal tubule, increase glucosuria and natriuresis, and thus decreases the serum glucose level and blood pressure. Furthermore, the tubuloglomerular feedback activated by the natriuresis can decrease glomerular hyperfiltration, acknowledged as the main foundation of renoprotection. Several studies have confirmed the protective effects of SGLT2 inhibitors on the kidneys of adult diabetic patients and those with non-diabetic nephropathy; however, limited researches are seen in paediatric patients. In this review, we have summarized the mechanisms of action of SGLT2 inhibitors, the current experiences in adults, results of exploratory studies in children, and adverse events & obstacles of paediatric use. We further explore the potential and possible future research direction of SGLT2 inhibitors in paediatric diseases.

Sodium-Glucose Cotransporter-2 Inhibitor (SGLT2i) as a Primary Preventative Agent in the Healthy Individual: A Need of a Future Randomised Clinical Trial?

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are a relatively novel class of drug for treating type 2 diabetes mellitus (T2DM) that inhibits glucose reabsorption in the renal proximal tubule to promote glycosuria and reduce blood glucose levels. SGLT2i has been clinically indicated for treating T2DM, with numerous recent publications focussing on both primary and secondary prevention of cardiovascular and renal events in Type 2 diabetic patients. The most recent clinical trials showed that SGLT2i have moderately significant beneficial effects on atherosclerotic major adverse cardiovascular events (MACE) in patients with histories of atherosclerotic cardiovascular disease. In this review and analysis, SGLT2i have however demonstrated clinically significant benefits in reducing hospitalisation for heart failure and worsening of chronic kidney disease (CKD) irrespective of pre-existing atherosclerotic cardiovascular disease or previous heart failure history. A meta-analysis suggests that all SGLT2 inhibitors demonstrated the therapeutic benefit on all-cause and cardiovascular mortality, as shown in EMPAREG OUTCOME study with a significant decrease in myocardial infarction, without increased stroke risk. All the above clinical trial recruited type 2 diabetic patients. This article aims to postulate and review the possible primary prevention role of SGLT2i in healthy individuals by reviewing the current literature and provide a prospective overview. The emphasis will include primary prevention of Type 2 Diabetes, Heart Failure, CKD, Hypertension, Obesity and Dyslipidaemia in healthy individuals, whom are defined as healthy, low or intermediate risks patients.

Optimizing Diet to Slow CKD Progression

Due to the unique role of the kidney in the metabolism of nutrients, patients with chronic kidney disease (CKD) lose the ability to excrete solutes and maintain homeostasis. Nutrient intake modifications and monitoring of nutritional status in this population becomes critical, since it can affect important health outcomes, including progression to kidney failure, quality of life, morbidity, and mortality. Although there are multiple hemodynamic and metabolic factors involved in the progression and prognosis of CKD, nutritional interventions are a central component of the care of patients with non-dialysis CKD (ND-CKD) and of the prevention of overweight and possible protein energy-wasting. Here, we review the reno-protective effects of diet in adults with ND-CKD stages 3-5, including transplant patients.

Transit and Metabolic Pathways of Quercetin in Tubular Cells: Involvement of Its Antioxidant Properties in the Kidney

Quercetin is a flavonoid with antioxidant, antiviral, antimicrobial, and anti-inflammatory properties. Therefore, it has been postulated as a molecule with great therapeutic potential. The renoprotective capacity of quercetin against various toxins that produce oxidative stress, in both in vivo and in vitro models, has been shown. However, it is not clear whether quercetin itself or any of its metabolites are responsible for the protective effects on the kidney. Although the pharmacokinetics of quercetin have been widely studied and the complexity of its transit throughout the body is well known, the metabolic processes that occur in the kidney are less known. Because of that, the objective of this review was to delve into the molecular and cellular events triggered by quercetin and/or its metabolites in the tubular cells, which could explain some of the protective properties of this flavonoid against oxidative stress produced by toxin administration. Thus, the following are analyzed: (1) the transit of quercetin to the kidney; (2) the uptake mechanisms of quercetin and its metabolites from plasma to the tubular cells; (3) the metabolic processes triggered in those cells, which affect the accumulation of metabolites in the intracellular space; and (4) the efflux mechanisms of these compounds and their subsequent elimination through urine. Finally, it is discussed whether those processes that are mediated in the tubular cells and that give rise to different metabolites are related to the antioxidant and renoprotective properties observed after the administration of quercetin.

Extracellular Vesicles and Renal Fibrosis: An Odyssey toward a New Therapeutic Approach

Renal fibrosis is a complex disorder characterized by the destruction of kidney parenchyma. There is currently no cure for this devastating condition. Extracellular vesicles (EVs) are membranous vesicles released from cells in both physiological and diseased states. Given their fundamental role in transferring biomolecules to recipient cells and their ability to cross biological barriers, EVs have been widely investigated as potential cell-free therapeutic agents. In this review, we provide an overview of EVs, focusing on their functional role in renal fibrosis and signaling messengers responsible for EV-mediated crosstalk between various renal compartments. We explore recent findings regarding the renoprotective effect of EVs and their use as therapeutic agents in renal fibrosis. We also highlight advantages and future perspectives of the therapeutic applications of EVs in renal diseases.

Renal outcomes of treatment with telmisartan in patients with stage 3-4 chronic kidney disease: A prospective, randomized, controlled trial (JINNAGA)

Objectives:

Although angiotensin II receptor blockers are effective for patients with chronic kidney disease, dose-dependent renoprotective effects of angiotensin II receptor blockers in patients with moderate to severe chronic kidney disease with non-nephrotic proteinuria are not known. Our aim was to elucidate the dose-dependent renoprotective effects of angiotensin II receptor blockers on such patients.

Methods:

A multicenter, prospective, randomized trial was conducted from 2009 to 2014. Patients with non-nephrotic stage 3–4 chronic kidney disease were randomized for treatment with either 40 or 80 mg telmisartan and were observed for up to 104 weeks. Overall, 32 and 29 patients were allocated to the 40 and 80 mg telmisartan groups, respectively. The composite primary outcome was renal death, doubling of serum creatinine level, transition to stage 5 chronic kidney disease, and death from any cause. Secondary outcomes included the level of urinary proteins and changes in the estimated glomerular filtration rate.

Results:

There was no difference in the primary outcome (p = 0.78) and eGFR (p = 0.53) between the two groups; however, after 24 weeks, urinary protein level was significantly lower in the 80 mg group than in the 40 mg group (p < 0.05). No severe adverse events occurred in either group, and the occurrence of adverse events did not significantly differ between them (p = 0.56).

Conclusion:

Our findings do not demonstrate a direct dose-dependent renoprotective effect of telmisartan. The higher telmisartan dose resulted in a decrease in the amount of urinary protein. Even though high-dose angiotensin II receptor blockers may be preferable for patients with stage 3–4 chronic kidney disease, the clinical importance of the study results may be limited. The study was registered in the UMIN-CTR (https://www.umin.ac.jp/ctr) with the registration number UMIN000040875.

Comparative Effectiveness of Renin-Angiotensin System Inhibitors and Calcium Channel Blockers in Individuals With Advanced CKD: A Nationwide Observational Cohort Study

RATIONALE & OBJECTIVE

It is unknown whether initiating renin-angiotensin system (RAS) inhibitor therapy in patients with advanced chronic kidney disease (CKD) is superior to alternative antihypertensive agents such as calcium channel blockers (CCBs). We compared the risks for kidney replacement therapy (KRT), mortality, and major adverse cardiovascular events (MACE) in patients with advanced CKD in routine nephrology practice who were initiating either RAS inhibitor or CCB therapy.

STUDY DESIGN

Observational study in the Swedish Renal Registry, 2007 to 2017.

SETTINGS & PARTICIPANTS

2,458 new users of RAS inhibitors and 2,345 CCB users with estimated glomerular filtration rates<30mL/min/1.73m² (CKD G4-G5 without KRT) who were being followed up by a nephrologist. As a positive control cohort, new users of the same drugs with CKD G3 (estimated glomerular filtration rate, 30-60mL/min/1.73m²) were evaluated.

EXPOSURES

RAS inhibitor versus CCB therapy initiation.

OUTCOME

Initiation of KRT (maintenance dialysis or transplantation), all-cause mortality, and MACE (composite of cardiovascular death, myocardial infarction, or stroke).

ANALYTICAL APPROACH

HRs with 95% CIs were estimated using propensity score-weighted Cox proportional hazards regression adjusting for demographic, clinical, and laboratory covariates.

RESULTS

Median age was 74 years, 38% were women, and median follow-up was 4.1 years. After propensity score weighting, there was significantly lower risk for KRT after new use of RAS inhibitors compared with new use of CCBs (adjusted HR, 0.79 [95% CI, 0.69-0.89]) but similar risks for mortality (adjusted HR, 0.97 [95% CI, 0.88-1.07]) and MACE (adjusted HR, 1.00 [95% CI, 0.88-1.15]). Results were consistent across subgroups and in as-treated analyses. The positive control cohort of patients with CKD G3 showed similar KRT risk reduction (adjusted HR, 0.67 [95% CI, 0.56-0.80]) with RAS inhibitor therapy compared with CCBs.

LIMITATIONS

Potential confounding by indication.

CONCLUSIONS

Our findings provide evidence from real-world clinical practice that initiation of RAS inhibitor therapy compared with CCBs may confer kidney benefits among patients with advanced CKD, with similar cardiovascular protection.

The phosphodiesterase 5 inhibitor tadalafil has renoprotective effects in a rat model of chronic kidney disease

Phosphodiesterase 5 inhibitors are widely used to treat erectile dysfunction and lower urinary tract symptoms with benign prostatic hyperplasia. Recent studies have indicated the renoprotective effects of this class of compounds. Whether renoprotection depends on blood pressure reduction remains controversial. In this study, we investigated the renoprotective effects of the phosphodiesterase 5 inhibitor, tadalafil, in a rat model of high-salt induced kidney injury with hypertension. Dahl salt-sensitive rats were fed a normal diet, high-salt (8% sodium chloride) diet, or high-salt diet with oral administration of either low- or high-dose tadalafil (1 and 10 mg kg-1  day-1 , respectively). Serum creatinine, urinary protein, and blood pressure were measured at baseline and after 8 weeks, at which point the rats were examined for glomerular injury and fibrosis. PAI1 mRNA levels were also evaluated. After 8 weeks, blood pressure, serum creatinine, and urinary protein levels were significantly higher in the high-salt group than those in the normal-salt group. Serum creatinine and urinary protein were significantly lower in both tadalafil groups than those in the high-salt group, while only high-dose tadalafil affected blood pressure. In addition, glomerulosclerosis and α-smooth muscle actin expression significantly decreased in both tadalafil treatment groups. PAI1 mRNA increased significantly in the high-salt group but decreased in both tadalafil-treated groups. Our results indicated that both low- and high-dose tadalafil prevented fibrosis and glomerular injury in a chronic kidney disease rat model. Mechanistically, these effects may be associated with PAI1 expression and glomerular structure protection.

Carnosine and Kidney Diseases: What We Currently Know?

Carnosine (beta-alanyl-L-histidine) is an endogenously synthesised dipeptide which is present in different human tissues e.g. in the kidney. Carnosine is degraded by enzyme serum carnosinase, encoding by CNDP1 gene. Carnosine is engaged in different metabolic pathways in the kidney. It reduces the level of proinflammatory and profibrotic cytokines, inhibits advanced glycation end products' formation, moreover, it also decreases the mesangial cell proliferation. Carnosine may also serve as a scavenger of peroxyl and hydroxyl radicals and a natural angiotensin-converting enzyme inhibitor. This review summarizes the results of experimental and human studies concerning the role of carnosine in kidney diseases, particularly in chronic kidney disease, ischemia/reperfusion-induced acute renal failure, diabetic nephropathy and also drug-induced nephrotoxicity. The interplay between serum carnosine concentration and serum carnosinase activity and polymorphism in the CNDP1 gene is discussed. Carnosine has renoprotective properties. It has a promising potential for the treatment and prevention of different kidney diseases, particularly chronic kidney disease which is a global public health issue. Further studies of the role of carnosine in the kidney may offer innovative and effective strategies for the management of kidney diseases.

Sodium-glucose linked transporter-2 inhibitor renal outcome modification in type 2 diabetes: Evidence from studies in patients with high or low renal risk

Data from three completed cardiovascular outcome trials (CVOTs), EMPA-REG OUTCOME, CANVAS Program and DECLARE-TIMI 58, add to the evidence supporting the potential renoprotective effects of sodium-glucose linked transporter-2 (SGLT2) inhibitors in patients with type 2 diabetes. Despite recommendations in recent guidelines, it is difficult to support a view that definitive evidence for renoprotection exists from these SGLT2 inhibitor CVOT results. To date, the only dedicated trial to report definitive data on the renal impact of SGLT2 inhibition is CREDENCE. Notably, the total number of patient-relevant renal endpoint events (dialysis, transplant or renal death) observed in CREDENCE was significantly higher than the total for all three CVOTs collectively (183 events/4401 patients vs. 69 events/34 322 patients, respectively), which shows the increased statistical power of CREDENCE for these renal endpoints. Treatment with canagliflozin was associated with a 30% relative risk reduction (RRR) in the primary composite endpoint of end-stage kidney disease, doubling of serum creatinine, or death from renal or cardiovascular causes and a 34% RRR for the renal-specific elements of this primary endpoint (P <0.001). Canagliflozin has therefore become the first US-approved SGLT2 inhibitor to include an indication for RRR, in addition to type 2 diabetes glycaemic control and cardiovascular risk reduction. While confirmatory of the exploratory data from CVOTs, CREDENCE provides the first robust data on the effects of canagliflozin on patient-relevant renal endpoints. Extrapolation to a conclusion of a SGLT2 inhibitor class effect cannot be made until additional renal trials with other SGLT2 inhibitors are reported.

Sodium-Glucose Cotransporter 2 Inhibitors and Kidney Outcomes: True Renoprotection, Loss of Muscle Mass or Both?

Inhibitors of sodium-glucose cotransporter 2 (SGLT2) have emerged as practice-changing treatments for patients with type 2 diabetes, reducing both the risk of cardiovascular events and kidney events. However, regarding the latter, caution is warranted, as these kidney endpoints are defined using glomerular filtration rate estimations based on creatinine, the non-enzymatic product of creatine residing in muscles. Creatinine-based estimations of the glomerular filtration rate are only valid if the treatment has no effect on changes in muscle mass over time. Yet, circumstantial evidence suggests that treatment with SGLT2 inhibitors does result in a loss of muscle mass, rendering serum creatinine-based kidney endpoints invalid. Currently, it cannot be excluded that the described renoprotective effect of SGLT2 inhibitors is in part or in whole the consequence of a loss of muscle mass. Post-hoc analyses of existing trials or new trials based on kidney function markers independent of muscle mass can provide more definitive answers on the proposed renoprotective effects of SGLT2 inhibitors.

The role of renal hypoxia in the pathogenesis of diabetic kidney disease: a promising target for newer renoprotective agents including SGLT2 inhibitors?

Diabetic kidney disease is the most common cause of end-stage kidney disease and poses a major global health problem. Finding new, safe, and effective strategies to halt this disease has proven to be challenging. In part that is because the underlying mechanisms are complex and not fully understood. However, in recent years, evidence has accumulated suggesting that chronic hypoxia may be the primary pathophysiological pathway driving diabetic kidney disease and chronic kidney disease of other etiologies and was called the chronic hypoxia hypothesis. Hypoxia is the result of a mismatch between oxygen delivery and oxygen demand. The primary determinant of oxygen delivery is renal perfusion (blood flow per tissue mass), whereas the main driver of oxygen demand is active sodium reabsorption. Diabetes mellitus is thought to compromise the oxygen balance by impairing oxygen delivery owing to hyperglycemia-associated microvascular damage and exacerbate oxygen demand owing to increased sodium reabsorption as a result of sodium-glucose cotransporter upregulation and glomerular hyperfiltration. The resultant hypoxic injury creates a vicious cycle of capillary damage, inflammation, deposition of the extracellular matrix, and, ultimately, fibrosis and nephron loss. This review will frame the role of chronic hypoxia in the pathogenesis of diabetic kidney disease and its prospect as a promising therapeutic target. We will outline the cellular mechanisms of hypoxia and evidence for renal hypoxia in animal and human studies. In addition, we will highlight the promise of newer imaging modalities including blood oxygenation level-dependent magnetic resonance imaging and discuss salutary interventions such as sodium-glucose cotransporter 2 inhibition that (may) protect the kidney through amelioration of renal hypoxia.

Sinapic acid attenuates cisplatin-induced nephrotoxicity through peroxisome proliferator-activated receptor gamma agonism in rats

AIM

The aim of this study was to investigate the involvement of peroxisome proliferator-activated receptor gamma (PPAR-γ) in renal protection offered by sinapic acid in cisplatin-induced nephrotoxicity in male rats.

MATERIALS AND METHODS

Nephrotoxicity was induced by single dose of cisplatin (5 mg/kg, intraperitoneal [i.p.]) in rats. Cisplatin-induced nephrotoxicity was assessed by measuring serum creatinine, creatinine clearance, urea, uric acid, potassium, magnesium levels, fractional excretion of sodium, and microproteinuria in rats. Superoxide anion generation, thiobarbituric acid reactive substances, myeloperoxidase activity, and reduced glutathione levels were measured to assess oxidative stress in renal tissues. Hematoxylin and eosin stain showed renal histological changes.

RESULTS

The significant changes in serum and urinary parameters, elevated oxidative stress, and renal histological changes established the induction of nephrotoxicity. Sinapic acid treatment (20 and 40 mg/kg, orally [p.o.]) provides dose-dependent and significant (P < 0.05) nephroprotection against cisplatin-mediated nephrotoxicity in rats. Nephroprotective effect of sinapic acid was abolished by PPAR-γ inhibitor, bisphenol A diglycidyl ether (30 mg/kg, i.p.) in rats.

CONCLUSION

It is concluded that PPAR-γ agonism serves as one of the mechanisms in sinapic acid-mediated renoprotection.

Comparative Effect of Curcumin and Nanocurcumin on Nephroprotection at Cisplatin-induced Rats

Background:

Cisplatin is a first-line chemotherapeutic agent for various solid tumors including ovarian and breast cancer. Thereby, it has been proven effective as an antineoplastic agent, but its clinically use is limited because of its nephrotoxicity side effect.

Aims and Objectives:

This study aimed to investigate curcumin as a renoprotector agent against cisplatin nephrotoxicity.

Materials and Methods:

The samples used were curcumin and its nanoparticles formulated using ionic gelation method. The nephrotoxicity was investigated through several parameters such as serum creatinine, blood urea nitrogen, serum albumin, kidney weight ratio, and histopathology. These parameters were tested on rats and divided into the following four groups: normal group, negative control group that administered cisplatin with doses amount of 7 mg/kg body weight (BW) intraperitoneally, nanocurcumin group (cisplatin + nanocurcumin) and curcumin group (cisplatin + curcumin). The agents were administered at a dose of 100 mg/kg BW every day in 9 days before cisplatin administration. The sample of blood serum and kidneys organ were taken 48h after cisplatin administration.

Results:

The negative control group showed a significant increase in serum creatinine, blood urea nitrogen, and kidney weight ratio, whereas it showed a significant decrease in serum albumin. The administration of sample agents showed a significant decrease in serum creatinine, blood urea nitrogen, and kidney weight ratio and an increase in the albumin level as compared to negative control group.

Conclusion:

Nanocurcumin showed significant improvement in kidneys more than curcumin. In contrast, histopathological examination verified the necrosis in negative control group, suggesting the renoprotection effect of nanocurcumin against nephrotoxicity on cisplatin-induced rats.

Renal Autocrine and Paracrine Signaling: A Story of Self-protection

Autocrine and paracrine signaling in the kidney adds an extra level of diversity and complexity to renal physiology. The extensive scientific production on the topic precludes easy understanding of the fundamental purpose of the vast number of molecules and systems that influence the renal function. This systematic review provides the broader pen strokes for a collected image of renal paracrine signaling. First, we recapitulate the essence of each paracrine system one by one. Thereafter the single components are merged into an overarching physiological concept. The presented survey shows that despite the diversity in the web of paracrine factors, the collected effect on renal function may not be complicated after all. In essence, paracrine activation provides an intelligent system that perceives minor perturbations and reacts with a coordinated and integrated tissue response that relieves the work load from the renal epithelia and favors diuresis and natriuresis. We suggest that the overall function of paracrine signaling is reno-protection and argue that renal paracrine signaling and self-regulation are two sides of the same coin. Thus local paracrine signaling is an intrinsic function of the kidney, and the overall renal effect of changes in blood pressure, volume load, and systemic hormones will always be tinted by its paracrine status.

Novel antidiabetic drugs in diabetic kidney disease accompanying type 2 diabetes - a minireview

Intensive hypoglycemic treatment is the strongest preventive strategy against the development of microvascular complications of type 2 diabetes (T2DM), including diabetic nephropathy. However, some antidiabetic drugs, i.e. sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and glucagon-like peptide-1 receptor agonists (GLP1-RA) have an additional renoprotective effect beyond glucose control by itself. Similar, both SGLT-2i and GLP1-RA have been demonstrated to decrease the risk of adverse cardiovascular (CV) events in CV outcome trials. Nevertheless, there are relevant differences in CV and renal effects of SGLT-2i and GLP1-RA. First, SGLT2i reduced the incidence and progression of albuminuria and prevented loss of kidney function, while predominant renal benefits of GLP1-RA were driven by albuminuria outcomes. Second, the risk of heart failure (HF) hospitalizations decreased on SGLT2i but not on GLP1-RA, which gives priority to SGLT2i in T2DM and HF, especially with depressed EF. Third, either GLP1-RA (reducing predominantly atherosclerosis-dependent events) or SGLT-2i, should be used in T2DM and established atherosclerotic CV disease (ASCVD) or other indicators of high CV risk. In this review, we have briefly compared clinical practice guidelines of the American Diabetes Association (2020 and 2021 versions), Polish Diabetes Association (2020) and the European Society of Cardiology/European Association for the Study of Diabetes (2019), with a focus on the choice between SGLT-2i and GLP1-RA in patients with diabetic kidney disease.

Renoprotection Provided by Additional Diuretic Treatment in Partially Nephrectomized Ren-2 Transgenic Rats Subjected to the Combined RAS and ETA Blockade

Objective

Our previous study in heterozygous Ren-2 transgenic rats (TGR) demonstrated that long-term treatment with endothelin receptor A (ET_A) blocker atrasentan added to the renin-angiotensin system (RAS) blockade had renoprotective effects in a model of chronic kidney disease (CKD) induced by partial nephrectomy. Since ET_A blockade is known to cause edema, we were interested whether diuretic treatment added to this therapy would be beneficial.

Design and Methods

Partial nephrectomy (NX) was performed at the age of 3 months in TGR rats which were subjected to: (i) RAS blockade alone (angiotensin receptor blocker losartan and angiotensin converting enzyme inhibitor trandolapril), (ii) combined RAS (losartan and trandolapril) and ET_A receptor blockade (atrasentan), or (iii) diuretic (hydrochlorothiazide) added to the combined RAS + ET_A blockade for 50 weeks following NX.

Results

At the end of the study systolic blood pressure and cardiac hypertrophy were similarly decreased in all treated groups. Survival was significantly improved by ET_A receptor blockade added to RAS blockade with no further effects of diuretic treatment. However, additional diuretic treatment combined with RAS + ET_A blockade decreased body weight and had beneficial renoprotective effects - reductions of both kidney weight and kidney damage markers. Proteinuria gradually increased in rats treated with RAS blockade alone, while it was substantially lowered by additional ET_A blockade. In rats treated with additional diuretic, proteinuria was progressively reduced throughout the experiment.

Conclusion

A diuretic added to the combined RAS and ET_A blockade has late renoprotective effects in CKD induced by partial nephrectomy in Ren-2 transgenic rats. The diuretic improved: renal function (evaluated as proteinuria and creatinine clearance), renal morphology (kidney mass, glomerular volume), and histological markers of kidney damage (glomerulosclerosis index, tubulointerstitial injury).

Beneficial Effects of the Angiotensin-Converting Enzyme 2 Activator Dize in Renovascular Hypertension

BACKGROUND

Angiotensin Converting Enzyme (ACE) 2 is an important modulator of the Renin Angiotensin System (RAS) and the RAS plays a central role in renovascular hypertension. Very few studies investigated the role of components of the counterregulatory RAS axis (ACE2, Ang-(1-7) and Mas receptor) in renovascular hypertension and the results are controversial.

OBJECTIVE

The aim of this study was to investigate the effects of Diminazene Aceturate (DIZE) administration on renal function and renal inflammation parameters in 2K1C hypertensive rats.

METHODS

Male Wistar rats were divided into three experimental groups: sham-operated animals, 2K1C+saline and 2K1C+DIZE orally (1 mg/kg/day). At the end of the 30 days of treatment, renal function was analyzed and kidneys from all the groups were collected and processed separately for measurement of N-acetyl-beta-D-glucosaminidase (NAG) and Myeloperoxidase (MPO) activities, cytokines, chemokines and nitric oxide levels.

RESULTS

Oral DIZE administration for 4 weeks in hypertensive rats attenuated renal dysfunction and reduced the levels of MPO and NAG, cytokines and chemokines (IL1β, IL-6, TNF-α and MCP-1) and increased urinary nitrate/nitrite levels in 2K1C hypertensive rats.

CONCLUSION

Our findings showed that ACE2 activation may effectively improve renal alterations and inflammation induced by renovascular hypertension.

Molecular Mechanisms of Epigallocatechin-3-Gallate for Prevention of Chronic Kidney Disease and Renal Fibrosis: Preclinical Evidence

Chronic kidney disease (CKD) is a common public health problem worldwide characterized by gradual decline of renal function over months/years accompanied by renal fibrosis and failure in tissue wound healing after sustained injury. Patients with CKD frequently present with profound signs/symptoms that require medical treatment, mostly culminating in hemodialysis and renal transplantation. To prevent CKD more efficiently, there is an urgent need for better understanding of the pathogenic mechanisms and molecular pathways of the disease pathogenesis and progression, and for developing novel therapeutic targets. Recently, several lines of evidence have shown that epigallocatechin-3-gallate (EGCG), an abundant phytochemical polyphenol derived from Camellia sinensis, might be a promising bioactive compound for prevention of CKD development/progression. This review summarizes current knowledge of molecular mechanisms underlying renoprotective roles of EGCG in CKD based on available preclinical evidence (from both in vitro and in vivo animal studies), particularly its antioxidant property through preservation of mitochondrial function and activation of Nrf2 (nuclear factor erythroid 2-related factor 2)/HO-1 (heme oxygenase-1) signaling, anti-inflammatory activity, and protective effect against epithelial mesenchymal transition. Finally, future perspectives, challenges, and concerns regarding its clinical use in CKD and renal fibrosis are discussed.

Diabetic nephropathy: an insight into molecular mechanisms and emerging therapies

Introduction: Diabetic kidney disease (DKD) is a major cause of morbidity and mortality in diabetes and is the most common cause of proteinuric and non-proteinuric forms of end-stage renal disease (ESRD). Control of risk factors such as blood glucose and blood pressure is not always achievable or effective. Significant research efforts have attempted to understand the pathophysiology of DKD and develop new therapies. Areas covered: We review DKD pathophysiology in the context of existing and emerging therapies that affect hemodynamic and metabolic pathways. Renin-angiotensin system (RAS) inhibition has become standard care. Recent evidence for renoprotective activity of SGLT2 inhibitors and GLP-1 agonists is an exciting step forward while endothelin receptor blockade shows promise. Multiple metabolic pathways of DKD have been evaluated with varying success; including mitochondrial function, reactive oxygen species, NADPH oxidase (NOX), transcription factors (NF-B and Nrf2), advanced glycation, protein kinase C (PKC), aldose reductase, JAK-STAT, autophagy, apoptosis-signaling kinase 1 (ASK1), fibrosis and epigenetics. Expert opinion: There have been major advances in the understanding and treatment of DKD. SGLT2i and GLP-1 agonists have demonstrated renoprotection, with novel therapies under evaluation. Addressing the interaction between hemodynamic and metabolic pathways may help achieve prevention, attenuation or even reversal of DKD.

The renoprotective effect of concomitant fosfomycin in the treatment of pulmonary exacerbations in cystic fibrosis

Background

Fosfomycin, effective in Cystic Fibrosis (CF), competes with aminoglycosides at renal binding sites and may therefore afford a renoprotective effect when used in combination therapy. We explored this by using markers of acute renal tubular damage [N-acetyl-β-d-glucose-aminidase (NAG), alanine amino-peptidase (AAP) and β₂-microglobulin].

Methods

Using a prospective randomized crossover trial design, at an acute pulmonary exacerbation, 18 adult CF patients received either 14 days of intravenous (IV) tobramycin or IV tobramycin and IV fosfomycin, both in combination with a second IV antibiotic (colomycin).

Results

Urinary NAG (P = 0.003) and AAP (P = 0.03) following treatment with concomitant fosfomycin were lower than those after treatment with tobramycin and colomycin alone. Fosfomycin attenuated the total 24-h urinary protein leak (P = 0.0001). The 14-day improvements in all surrogate markers of exacerbation resolution (FEV₁% predicted, FVC, white cell count and C-reactive protein) were similar for both treatment regimens.

Conclusion

The addition of fosfomycin reduces acute renal injury caused by IV aminoglycoside therapy in CF pulmonary exacerbations.

New Rice-Derived Short Peptide Potently Alleviated Hyperuricemia Induced by Potassium Oxonate in Rats

Gout that caused by hyperuricemia affects human health seriously and more efficient drugs are urgently required clinically. In this study, a novel peptide named RDP1 (AAAAGAKAR, 785.91 Da) was identified from the extract of shelled fruits of Oryza sativa. Our results demonstrated that RDP1 (the minimum effective concentration is 10 μg/kg) could significantly reduce the serum uric acid and creatinine and alleviate hyperuricemic nephropathy in rats by intragastric administration. RDP1 inhibited xanthine oxidase, which also was verified at the animal level. Results from molecular docking indicated that RDP1 can inhibit uric acid formation by occupying the binding site of xanthine oxidase to xanthine. Besides, RDP1 showed no toxicity on rats and was stable in several temperatures, demonstrating its advantages for transportation. This research was the first discovery of antihyperuricemic peptide from the shelled fruits of O. Sativa and provided a new candidate for the development of hypouricemic drugs.

Protective Effects of Epigallocatechin-3-Gallate from Green Tea in Various Kidney Diseases

Kidney diseases are common health problems worldwide. Various etiologies (e.g., diabetes, hypertension, drug-induced nephrotoxicity, infection, cancers) can affect renal function and ultimately lead to development of chronic kidney disease (CKD) and end-stage renal disease (ESRD). The global rise in number of CKD/ESRD patients during recent years has led to tremendous concern to look for effective strategies to prevent or slow progression of CKD and ESRD. Natural compounds derived from herbs or medicinal plants have gained wide attention for scientific scrutiny to achieve such goals. One of such natural compounds that has been extensively investigated is epigallocatechin-3-gallate (EGCG), a major polyphenol found in the tea plant (Camellia sinensis). A growing body of recent evidence has shown that EGCG may be a promising therapeutic or protective agent in various kidney diseases. This article thus highlights recent progress in medical research on beneficial effects of EGCG against a broad spectrum of kidney diseases, including acute kidney injury, cisplatin-induced nephrotoxicity, kidney stone disease, glomerulonephritis, lupus nephritis, renal cell carcinoma, diabetic nephropathy, CKD, and renal fibrosis. The renoprotective mechanisms are also detailed. Finally, future perspectives of medical research on EGCG and its potential use in clinical practice for treatment and prevention of kidney diseases are discussed.

Comparison of the changes in the factors associated with the renal prognosis of non-elderly and elderly subjects treated with empagliflozin- a retrospective observation study in Japanese patients with type 2 diabetes

PURPOSE

The factors associated with the renal prognosis over six months after the initiation of empagliflozin were compared between the non-elderly and elderly Japanese patients with type 2 diabetes.

PATIENTS AND METHODS

In total, 132 patients treated with empagliflozin (10 mg, once daily) were studied as the safety analysis set. One hundred ten subjects whose medications were not changed during the observation period were investigated as the full analysis set to assess the effectiveness. The subjects were divided into two groups: non-elderly subjects (n=72) of<65 years of age and elderly subjects (n=38) of≥65 years of age.

RESULTS

Although the body weight and HbA1c, AST, ALT and γ-GTP levels were significantly reduced in both the non-elderly and elderly subjects, blood pressure, eGFR and urinary protein excretion were only significantly decreased in the non-elderly subjects. The hemoglobin, hematocrit and serum HDL-cholesterol levels were significantly elevated in both groups. The change in eGFR showed a significant positive association with the change in blood pressure. The change in urinary protein excretion tended to be correlated with the change in blood pressure.

CONCLUSION

Although renoprotective effects might be limited, empagliflozin can safely and effectively improve metabolic parameters, even in elderly subjects.

Metformin: A Candidate Drug for Renal Diseases

Over the past decades metformin has been the optimal first-line treatment for type 2 diabetes mellitus (T2DM). Only in the last few years, it has become increasingly clear that metformin exerts benign pleiotropic actions beyond its prescribed use and ongoing investigations focus on a putative beneficial impact of metformin on the kidney. Both acute kidney injury (AKI) and chronic kidney disease (CKD), two major renal health issues, often result in the need for renal replacement therapy (dialysis or transplantation) with a high socio-economic impact for the patients. Unfortunately, to date, effective treatment directly targeting the kidney is lacking. Metformin has been shown to exert beneficial effects on the kidney in various clinical trials and experimental studies performed in divergent rodent models representing different types of renal diseases going from AKI to CKD. Despite growing evidence on metformin as a candidate drug for renal diseases, in-depth research is imperative to unravel the molecular signaling pathways responsible for metformin's renoprotective actions. This review will discuss the current state-of-the-art literature on clinical and preclinical data, and put forward potential cellular mechanisms and molecular pathways by which metformin ameliorates AKI/CKD.

Ischemic preconditioning improved renal ischemia/reperfusion injury and hyperglycemia

Renal ischemia/reperfusion (I/R) is an alternation of renal hemodynamics, which results in diverse postischemic responses and eventually acute kidney injury. Although renal ischemic preconditioning (IPC) is known to protect the kidney from I/R injury, the precise renoprotective mechanisms are not completely understood. The multiple renoprotective effects of IPC underscore the importance in understanding molecular mechanisms and the targets of action involved. This study aimed to identify the biochemical changes in renal I/R injury and investigate the renoprotective mechanisms of IPC. Herein, renal I/R was produced in adult male Sprague-Dawley rats through the bilateral ligation of renal pedicles for 45 min, followed by reperfusion for 24 h. For the IPC group, rats were subjected to three cycles of 2-min ischemia, followed by a 5-min reperfusion, 15 min prior to renal I/R. Our data confirmed the beneficial effects that IPC has on renal I/R injury. IPC-mediated renoprotection was associated with the resolution of oxidative stress, inflammation, apoptosis, and hyperglycemia. Among the numerous signaling molecules involved in the renoprotective mechanisms of IPC, an elevated protein expression of Nrf2, HO-1, LC3 II conversion, along with Atg12 and protein phosphorylation of AMPK, as well as a decreased protein phosphorylation of ERK, p38 MAPK, and Akt and NF-κB DNA binding activity were identified. Importantly, the post renal I/R overproduction of counter-regulatory hormones, impaired hepatic insulin action, and augmented hepatic gluconeogenesis were improved through IPC. As counter-regulatory hormones have been implicated in the induction of oxidative stress, inflammation, apoptosis, impaired insulin action, hyperglycemia, and tissue destruction, our findings suggest that counter-regulatory hormones may well be valuable targets of IPC for combatting renal I/R injury. © 2018 IUBMB Life, 71(3):321-329, 2019.

[Research progress on preventions of ischemia-reperfusion injury during kidney transplant]

During kidney transplant, the non-specific inflammatory response induced by ischemia-reperfusion injury (IRI) will lead to decreased survival ability of transplanted kidney. However, the effect of IRI on long-term survival rate of allograft is not sure. Here we illuminated the relationship between early IRI and decreased long-term survival ability of allograft by retrospectively analyzing the clinical evidences and laboratory investigations. Previous studies showed that early IRI resulted in the graft loss through reduction of renal functional mass, vascular injury, chronic hypoxia and subsequent fibrosis. IRI was also one of the main factors to induce dysfunction of transplanted kidney and acute rejection reaction, and to decrease the allograft survival. Therefore, it's better to substitute traditional methods with novel measures during kidney transplant which may relieve the renal IRI much better.

Cardiovascular risk in chronic kidney disease: what is new in the pathogenesis and treatment?

The prevalence of chronic kidney disease (CKD) has increased markedly over past decades due to the aging of the worldwide population. Despite the progress in the prevention and treatment, the cardiovascular (CV) morbidity and mortality remain high among patients with CKD. Although CKD is a progressive and irreversible condition, it is possible to slow decreasing kidney function, as well as the development and progression of associated with kidney disease comorbidities. Diabetes mellitus has become major cause of CKD worldwide. It is estimated that the prevalence of diabetes will increase from 425 million worldwide in 2017 to 629 million by 2045, substantially the percentage of diabetic nephropathy among CKD patients is set to rise markedly. The results of multicenter trials concerning novel antidiabetic drugs suggest that efficacy in reducing CV risk is independent of the improvement in glycemic control. This review discusses underlying causes of high CV risk and strategies reducing individual burden among CKD patients.