Atrasentan for the treatment of diabetic nephropathy

Machine learning application identifies plasma markers for proteinuria in metastatic colorectal cancer patients treated with Bevacizumab

BACKGROUND AND OBJECTIVES

Proteinuria is a common complication after the application of bevacizumab therapy in patients with metastatic colorectal cancer, and severe proteinuria can lead to discontinuation of the drug. There is a lack of sophisticated means to predict bevacizumab-induced proteinuria, so the present study aims to predict bevacizumab-induced proteinuria using peripheral venous blood samples.

METHODS

A total of 122 subjects were enrolled and underwent pre-treatment plasma markers, and we followed them for six months with proteinuria as the endpoint event. We then analyzed the clinical features and plasma markers for grade ≥ 2 proteinuria occurrence using machine learning to construct a model with predictive utility.

RESULTS

One hundred sixteen subjects were included in the statistical analysis. We found that high baseline systolic blood pressure, low baseline HGF, high baseline ET1, high baseline MMP2, and high baseline ACE1 were risk factors for the development of grade ≥ 2 proteinuria in patients with metastatic colorectal cancer who received bevacizumab. Then, we constructed a support vector machine model with a sensitivity of 0.889, a specificity of 0.918, a precision of 0.615, and an F1 score of 0.727.

CONCLUSION

We constructed a machine learning model for predicting grade ≥ 2 bevacizumab-induced proteinuria, which may provide proteinuria risk assessment for applying bevacizumab in patients with metastatic colorectal cancer.

Research progress on the role of ET-1 in diabetic kidney disease

Diabetic kidney disease (DKD) is one of the common complications of diabetes mellitus, which usually progresses to end-stage renal disease and causes great damage to the health of patients. Endothelin-1 (ET-1), a molecule closely associated with the progression of DKD, has increased expression in response to high glucose stimulation and is involved in hemodynamic changes, inflammation, glomerular and tubular dysfunction in the kidney, causing an increase in proteinuria and a decrease in glomerular filtration function, ultimately leading to glomerulosclerosis and renal failure. This paper aims to review the molecular level changes, regulatory mechanisms, and mechanisms of action of ET-1 under DKD, clinical trials of ET-1 receptor antagonists in recent years and current problems, to provide basic information and new research directions and ideas for the treatment of DKD and ET-1-related research.

Efficacy and safety of drugs for people with type 2 diabetes mellitus and chronic kidney disease on kidney and cardiovascular outcomes: A systematic review and network meta-analysis of randomized controlled trials

AIM

To evaluate the comparative efficacy and safety of promising kidney protection drugs, including sodium-glucose cotransporter-2 inhibitors (SGLT-2Is), glucagon-like peptide-1 receptor agonists (GLP-1RAs), dipeptidyl-peptidase IV Inhibitors (DPP-4Is), aldosterone receptor agonists (MRAs), endothelin receptor antagonist (ERAs), pentoxifylline (PTF), and pirfenidone (PFD), on cardiovascular and kidney outcomes in type 2 diabetes (T2DM) and chronic kidney disease (CKD) population.

METHODS

PubMed, Embase, and Cochrane Library were searched from inception to August 12, 2022. We used the Bayesian model for network meta-analyses, registered in the PROSPERO (CRD42022343601).

RESULTS

This network meta-analysis identified 2589 citations, and included 27 eligible trials, enrolling 50,237 patients. All results presented below were moderate to high quality. For kidney outcomes, SGLT-2Is were optimal in terms of reducing composite kidney events (RR 0.69, 95%CI 0.61-0.79), and slowing eGFR slope (MD1.34, 95%CI 1.06-1.62). Then MRAs (RR 0.77, 95%CI 0.68-0.88; MD 1.31, 95%CI 0.89-1.74), GLP-1RAs (RR 0.78, 95%CI 0.62-0.97; MD 0.75, 95%CI 0.46-1.05), and ERAs (RR 0.75, 95%CI 0.57-0.99; MD 0.7, 95%CI 0.3-1.1) were followed in parallel. For cardiovascular outcomes, SGLT-2 inhibitors were also among the best for lowing the risk of heart failure hospitalization (RR 0.67, 95%CI 0.57-0.78), followed by GLP-1RAs (RR 0.73, 95%CI 0.55-0.97) and MRAs (RR 0.79, 95%CI 0.67-0.92). SGLT-2Is (RR 0.8, 95%CI 0.71-0.89) and GLP-1RAs (RR 0.72, 95%CI 0.6-0.86) had comparable effects to reduce the risk of major adverse cardiovascular events. MRAs were possibly associated with increased drug discontinuation due to adverse events (RR 1.21, 95%CI 1.05-1.38). For the hyperkalemia outcome, MRAs (RR 2.08, 95%CI 1.86-2.33) were linked to the risk of hyperkalemia, whereas SGLT-2Is (RR 0.78, 95%CI 0.65-0.93) were in contrast.

CONCLUSIONS

SGLT-2Is significantly reduced kidney and cardiovascular risk in T2DM and CKD, subsequently GLP-1RAs and MRAs. SGLT-2Is-MRAs combination might be a recommended treatment regimen for maximizing kidney and cardiovascular protection but with a low risk of hyperkalemia in T2DM and CKD.

Novel Aspects of the Immune Response Involved in the Peritoneal Damage in Chronic Kidney Disease Patients under Dialysis

Chronic kidney disease (CKD) incidence is growing worldwide, with a significant percentage of CKD patients reaching end-stage renal disease (ESRD) and requiring kidney replacement therapies (KRT). Peritoneal dialysis (PD) is a convenient KRT presenting benefices as home therapy. In PD patients, the peritoneum is chronically exposed to PD fluids containing supraphysiologic concentrations of glucose or other osmotic agents, leading to the activation of cellular and molecular processes of damage, including inflammation and fibrosis. Importantly, peritonitis episodes enhance peritoneum inflammation status and accelerate peritoneal injury. Here, we review the role of immune cells in the damage of the peritoneal membrane (PM) by repeated exposure to PD fluids during KRT as well as by bacterial or viral infections. We also discuss the anti-inflammatory properties of current clinical treatments of CKD patients in KRT and their potential effect on preserving PM integrity. Finally, given the current importance of coronavirus disease 2019 (COVID-19) disease, we also analyze here the implications of this disease in CKD and KRT.

Targeting inflammation to treat diabetic kidney disease: the road to 2030

Diabetic kidney disease (DKD) is one of the fastest growing causes of chronic kidney disease and associated morbidity and mortality. Preclinical research has demonstrated the involvement of inflammation in its pathogenesis and in the progression of kidney damage, supporting clinical trials designed to explore anti-inflammatory strategies. However, the recent success of sodium-glucose cotransporter-2 inhibitors and the nonsteroidal mineralocorticoid receptor antagonist finerenone has changed both guidelines and standard of care, rendering obsolete older studies directly targeting inflammatory mediators and the clinical development was discontinued for most anti-inflammatory drugs undergoing clinical trials for DKD in 2016. Given the contribution of inflammation to the pathogenesis of DKD, we review the impact on kidney inflammation of the current standard of care, therapies undergoing clinical trials, or repositioned drugs for DKD. Moreover, we review recent advances in the molecular regulation of inflammation in DKD and discuss potential novel therapeutic strategies with clinical relevance. Finally, we provide a road map for future research aimed at integrating the growing knowledge on inflammation and DKD into clinical practice to foster improvement of patient outcomes.

The novel role of ER protein TXNDC5 in the pathogenesis of organ fibrosis: mechanistic insights and therapeutic implications

Fibrosis-related disorders account for an enormous burden of disease-associated morbidity and mortality worldwide. Fibrosis is defined by excessive extracellular matrix deposition at fibrotic foci in the organ tissue following injury, resulting in abnormal architecture, impaired function and ultimately, organ failure. To date, there lacks effective pharmacological therapy to target fibrosis per se, highlighting the urgent need to identify novel drug targets against organ fibrosis. Recently, we have discovered the critical role of a fibroblasts-enriched endoplasmic reticulum protein disulfide isomerase (PDI), thioredoxin domain containing 5 (TXNDC5), in cardiac, pulmonary, renal and liver fibrosis, showing TXNDC5 is required for the activation of fibrogenic transforming growth factor-β signaling cascades depending on its catalytic activity as a PDI. Moreover, deletion of TXNDC5 in fibroblasts ameliorates organ fibrosis and preserves organ function by inhibiting myofibroblasts activation, proliferation and extracellular matrix production. In this review, we detailed the molecular and cellular mechanisms by which TXNDC5 promotes fibrogenesis in various tissue types and summarized potential therapeutic strategies targeting TXNDC5 to treat organ fibrosis.

Levels of angiotensin II type-1 receptor antibodies and endothelin-1 type-A receptor antibodies correlate with antibody-mediated rejection and poor graft function in kidney-transplantation patients

OBJECTIVE

Angiotensin II type-1 receptor antibodies (AT1R-Ab) and endothelin-1 type-A receptor antibodies (ETAR-Ab) are non-human leukocyte antigen (HLA) antibodies that can elicit adverse effects on kidney transplantation (KT) outcomes. We investigated the correlation between levels of AT1R-Ab and ETAR-Ab and postoperative outcomes in KT recipients.

METHODS

Pre-KT and post-KT serum from 79 patients was collected. Post-KT serum was collected within 1 year after KT or simultaneously as the biopsy. Levels of AT1R-Ab and ETAR-Ab were measured using enzyme-linked immunosorbent assay kits. AT1R-Ab >17.0 U/mL and ETAR-Ab >10.0 U/mL was considered to denote positivity according to manufacturer recommendations. We measured donor-specific antibodies against human leukocyte antigens (HLA-DSA) levels using LABScreen™ single-antigen kits.

RESULTS

Seventy-nine (54 men, 25 women) formed the study cohort. Seven (8.7%) patients were positive for AT1R-Ab, 25 (31.6%) patients were positive for both AT1R-Ab and ETAR-Ab, and 47 (59.5%) were negative for both antibodies at all time points. No patients died during the study period. Patients with both AT1R-Ab and ETAR-Ab were associated with a higher prevalence of antibody-mediated rejection (AMR) and lower estimated glomerular filtration rate, but not allograft loss or delayed graft function. AT1R-Ab were associated with T-cell-mediated rejection, but the association was not significant. HLA-DSA were associated significantly with a higher creatinine level in serum at 12 months and 24 months in patients with AT1R-Ab and/or ETAR-Ab.

CONCLUSIONS

AT1R-Ab, ETAR-Ab, and HLA-DSA were associated with a higher prevalence of AMR and decline in graft function. Measurement of levels of AT1R-Ab and ETAR-Ab in KT patients may be useful for stratification of immunological risk and identification of patients at a high risk of adverse graft outcome.

The Summarized Assessment of Endothelin A Receptor Expression in Renal Transplant Compartments Associated with Antibody-Mediated Rejection

The occurrence of anti-endothelin A receptor antibodies may be useful in diagnosis of transplant damage. We noticed that the presence of the endothelin A receptor (ETA receptor) in biopsy compartments is yet to be defined. We decided therefore to analysed the presence and relevance of the ETA receptor in biopsy to define the cause. Our study aims to evaluate the expression of ETA receptors in renal recipients after a biopsy due to the worsening of transplant function.

METHODS

The expression of ETA receptors was analyzed in renal transplant biopsies using the immunohistochemical method. The evaluation of ETA receptors was performed on paraffin sections. ETA receptor expression was analyzed in four compartments of renal transplant biopsies: glomeruli; vessels; tubular epithelium; and interstitium. The assessment was presented using a three-step scale (0: lack of expression; 1: mild to moderate immunoreactivity; 2: high expression). The results of each compartment from a single biopsy were summarized and assessed in the context of antibody-mediated rejection (AMR).

RESULTS

We analyzed 156 patients who had a renal allograft biopsy after renal transplantation. For each patient, we created a summarized ETA receptor expression score. The summarized ETA receptor expression score analysis showed statistically significant differences in patients with and without AMR. In addition, we noticed that patients with AMR had a significantly higher mean summarized expression of ETA receptor score of 3.28 ± 1.56 compared to patients who had a biopsy for other reasons with a mean summarized ETA receptor expression score of 1.47 ± 1.35 (p < 0.000001). ROC analysis of the ETA receptor expression score for detecting AMR status showed that the most appropriate cut-off for the test of the chosen binary classifier is between 2 and 3 of the summarized ETA receptor expression score.

CONCLUSIONS

The expression of endothelin A receptors in renal transplant compartments may be associated with antibody-mediated rejection. The positive ETA receptor staining might be a vital feature in the diagnosis of damage in AMR. The summarized ETA receptor expression score seems to be an exciting diagnostic tool in transplant injury assessment.

Diabetic kidney disease in type 2 diabetes: a review of pathogenic mechanisms, patient-related factors and therapeutic options

The global prevalence of diabetic kidney disease is rapidly accelerating due to an increasing number of people living with type 2 diabetes. It has become a significant global problem, increasing human and financial pressures on already overburdened healthcare systems. Interest in diabetic kidney disease has increased over the last decade and progress has been made in determining the pathogenic mechanisms and patient-related factors involved in the development and pathogenesis of this disease. A greater understanding of these factors will catalyse the development of novel treatments and influence current practice. This review summarises the latest evidence for the factors involved in the development and progression of diabetic kidney disease, which will inform better management strategies targeting such factors to improve therapeutic outcomes in patients living with diabetes.

Towards Better Drug Repositioning: Targeted Immunoinflammatory Therapy for Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common and important microvascular complications of diabetes mellitus (DM). The main clinical features of DN are proteinuria and a progressive decline in renal function, which are associated with structural and functional changes in the kidney. The pathogenesis of DN is multifactorial, including genetic, metabolic, and haemodynamic factors, which can trigger a sequence of events. Controlling metabolic risks such as hyperglycaemia, hypertension, and dyslipidaemia is not enough to slow the progression of DN. Recent studies emphasized immunoinflammation as a critical pathogenic factor in the progression of DN. Therefore, targeting inflammation is considered a potential and novel treatment strategy for DN. In this review, we will briefly introduce the inflammatory process of DN and discuss the anti-inflammatory effects of antidiabetic drugs when treating DN.

Improving the Dysregulation of FoxO1 Activity Is a Potential Therapy for Alleviating Diabetic Kidney Disease

A substantial proportion of patients with diabetes will develop kidney disease. Diabetic kidney disease (DKD) is one of the most serious complications in diabetic patients and the leading cause of end-stage kidney disease worldwide. Although some mechanisms have been revealed to contribute to the understanding of the pathogenesis of DKD and some drugs currently in use have been shown to be beneficial, prevention and management of DKD remain tricky and challenging. FoxO1 transcriptional factor is a crucial regulator of cellular homeostasis and posttranslational modification is a major mechanism to alter FoxO1 activity. There is increasing evidence that FoxO1 is involved in the regulation of various cellular processes such as stress resistance, autophagy, cell cycle arrest, and apoptosis, thereby playing an important role in the pathogenesis of DKD. Improving the dysregulation of FoxO1 activity by natural compounds, synthetic drugs, or manipulation of gene expression may attenuate renal cell injury and kidney lesion in the cells cultured under a high-glucose environment and in diabetic animal models. The available data imply that FoxO1 may be a potential clinical target for the prevention and treatment of DKD.

Silencing of LncRNA PVT1 inhibits the proliferation, migration and fibrosis of high glucose-induced mouse mesangial cells via targeting microRNA-93-5p

Objective: The present study aimed to investigate the regulatory role of long non-coding RNA plasmacytoma variant translocation 1 (PVT1) on high glucose (HG)-induced mouse mesangial cells (MMCs).

Methods: PVT1 expression in diabetic nephropathy (DN) mice and HG-induced MMCs was detected by qRT-PCR. EdU and Colony formation, Annexin V-PI staining, Muse cell cycle, Scratch, and Transwell assays were performed to detect the cell proliferation, apoptosis, cell cycle, migration, and invasion, respectively. The contents of fibrosis factors in cell-culture supernatants were detected by enzyme-linked immunosorbent assay (ELISA). Western blot was performed to detect the expression of factors involved in apoptosis, cell cycle, migration and invasion, fibrosis, and PI3K/Akt/mTOR pathway. The targeting relation between miR-93-5p and PVT1 was predicted by StarBase3.0 (an online software for analyzing the targeting relationship) and identified by Dual-luciferase reporter (DLR) assay.

Results: PVT1 was overexpressed in DN kidney tissues and HG-induced MMCs. HG-induced MMCs exhibited significantly increased EdU-positive cells, cell colonies, S and G₂/M phase cells, migration and invasion ability, and contents of fibrosis factors, as well as significantly decreased apoptosis rate compared with NG-induced MMCs. HG significantly up-regulated Bcl-2, CyclinD1, CDK4, N-cadherin, vimentin, Col. IV, FN, TGF-β1 and PAI-1, and down-regulated Bax, cleaved caspase-3, cleaved PARP, and E-cadherin in MMCs. Silencing of PVT1 eliminated the effects of HG in MMCs and blocked PI3K/Akt/mTOR pathway. MiR-93-5p was a target of PVT1, which eliminated the effects of PVT1 on HG-induced MMCs.

Conclusions: PVT1 silencing inhibited the proliferation, migration, invasion and fibrosis, promoted the apoptosis, and blocked PI3K/Akt/mTOR pathway in HG-induced MMCs via up-regulating miR-93-5p.

Endothelin A Receptors Expressed in Glomeruli of Renal Transplant Patients May Be Associated with Antibody-Mediated Rejection

BACKGROUND

Non-human leukocyte antigen (HLA) anti-endothelin A receptor antibodies are presented as being potentially important, but the expression of the endothelin A receptor in glomeruli (ETA receptor (g+)) has not yet been described. We decided to evaluate the presence and relevance of the ETA receptor in for-cause renal transplant biopsies. The aim of our study was to evaluate the immunoreactivity of the ETA receptor and its significance in patients who underwent a renal transplant biopsy due to the deterioration of transplant function, with detailed characterization of staining in glomeruli.

METHODS

The immunohistochemical expression of ETA receptor (ETAR) was analyzed in renal transplant biopsies. Microscopic evaluation was performed on paraffin sections in glomeruli. The analysis was performed using a two-step scale (0: lack of ETAR expression; 1: the presence of ETAR expression-mild to moderate immunoreactivity).

RESULTS

We analyzed 149 patients who underwent renal allograft biopsy after renal transplantation. Positive staining of ETA receptors in glomeruli (ETA receptor (g+)) was noticed in 13/149 (8.7%) patients. Five of these 13 (38.5%) patients with ETA receptor (g+) developed antibody-mediated rejection (AMR), while 13 of the remaining 136 (9.5%) ETA receptor (g-) patients developed AMR (p = 0.0022). Graft loss was noticed in all but one ETA receptor (g+) patient with AMR (4/5; 80%), but only in 2/13 (15%) ETA receptor (g-) patients with AMR (p = 0.009) during the first year after biopsy.

CONCLUSIONS

The expression of endothelin A receptors in glomeruli seems to be a potentially important feature in the diagnosis of damage during antibody-mediated rejection. It may help to identify patients at a higher risk of allograft rejection and injury.

Selective endothelin A receptor antagonism in patients with proteinuric chronic kidney disease

Introduction: Selective antagonists of Endothelin-1 receptors (ERA) have been tested in diabetic and nondiabetic chronic kidney disease (CKD). The SONAR trial (Study Of diabetic Nephropathy with AtRasentan) was the first randomized, phase 3, study assessing the long-term effect of ERA on CKD progression.Areas covered: We examine the ERA effects in proteinuric CKD. We discuss the results of the main clinical studies on ERA in CKD and offer an opinion on the findings of SONAR study and future perspectives in this field. We searched in PubMed and ISI Web of Science databases for including experimental and clinical studies that evaluated ERA in proteinuric CKD.Expert opinion: The SONAR study demonstrated that ERA confers protection against risk for CKD progression. This trial stimulated clinical research on ERA, to expand the therapeutic opportunities in CKD patients. Two novel phase 3 studies testing ERA in patients with glomerular disease are ongoing. Within the context of personalized medicine, we think it would be relevant to evaluate the effect of multiple treatments, including ERA, in proteinuric CKD patients. Testing ERA in clinical trials of novel design will also help at identifying the patients who would more benefit from these drugs.

The Potential Roles of Artemisinin and Its Derivatives in the Treatment of Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a chronic disease that has become a global public health problem. Studies on T2DM prevention and treatment mostly focus on discovering therapeutic drugs. Artemisinin and its derivatives were originally used as antimalarial treatments. In recent years, the roles of artemisinins in T2DM have attracted much attention. Artemisinin treatments not only attenuate insulin resistance and restore islet ß-cell function in T2DM but also have potential therapeutic effects on diabetic complications, including diabetic kidney disease, cognitive impairment, diabetic retinopathy, and diabetic cardiovascular disease. Many in vitro and in vivo experiments have confirmed the therapeutic utility of artemisinin and its derivatives on T2DM, but no article has systematically demonstrated the specific role artemisinin plays in the treatment of T2DM. This review summarizes the potential therapeutic effects and mechanism of artemisinin and its derivatives in T2DM and associated complications, providing a reference for subsequent related research.

Endothelin receptor antagonists for the treatment of diabetic nephropathy: A meta-analysis and systematic review

BACKGROUND

Diabetic nephropathy (DN) is the main cause of chronic kidney disease and end-stage renal disease worldwide. Although available clinical trials have shown that endothelin receptor (ER) antagonists may be a novel and beneficial drug for DN, no consistent conclusions regarding their sufficient effectiveness and safety for patients with DN have been presented.

AIM

To assess the effectiveness and safety of ER antagonists among patients with DN.

METHODS

The EMBASE, PubMed, MEDLINE, Cochrane, and ClinicalTrials.gov databases were searched without any language restrictions. Relative risks with 95% confidence intervals (CIs) for dichotomous data and mean differences or standardized mean difference with 95%CIs for continuous data were calculated using Review Manager 5.3 software. Publication bias was assessed using Egger's test with Stata/SE software.

RESULTS

We enrolled seven studies with six data sets and 5271 participants. The ER antagonists group showed a significantly greater reduction in albuminuria and more patients with 40% reduction in urinary albumin-to-creatinine ratio than the control group (P < 0.0001 and P = 0.02, respectively). Subgroup analysis for reductions in estimated glomerular filtration rate (eGFR) showed that for the middle-dosage subgroup, the ER antagonists group exhibited lower eGFR reduction than the control group (P < 0.00001; mean difference, 0.70 95%CI: 0.66, 0.74). Moreover, significant reductions in systolic and diastolic blood pressure were observed in the invention group.

CONCLUSION

ER blockades combined with angiotensin converting enzyme inhibitor /angiotensin II type 1 receptor blockers may be an effective treatment to lower blood pressure and reduce proteinuria in DN with declined eGFR. However, attention should be given to adverse events, including cardiac failure, anemia, and hypoglycemia, as well as serious adverse events.

The Role of Endothelin and Endothelin Antagonists in Chronic Kidney Disease

Background

Endothelins (ET) are a family of peptides that act as potent vasoconstrictors and pro-fibrotic growth factors. ET-1 is integral to renal and cardiovascular pathophysiology and exerts effects via autocrine, paracrine and endocrine signaling pathways tied to regulation of aldosterone, catecholamines, and angiotensin. In the kidney, ET-1 is critical to maintaining renal perfusion and controls glomerular arteriole tone and hemodynamics. It is hypothesized that ET-1 influences the progression of chronic kidney disease (CKD), and the objective of this review is to discuss the pathophysiology, and role of ET and endothelin receptor antagonists (ERAs) in CKD.

Summary

The use of ERAs in hypertensive nephropathy has the potential to decrease proteinuria, and in diabetic nephropathy has the potential to restore glycocalyx thickness, also decreasing proteinuria. Focal segmental glomerular sclerosis has no specific Food and Drug Administration-approved therapy currently, however, ERAs show promise in decreasing proteinuria and slowing tissue damage. ET-1 is a potential biomarker for autosomal dominant polycystic kidney disease progression and so it is thought that ERAs may be of some therapeutic benefit.

Key Messages

Multiple studies have shown the utility of ERAs in CKD. These agents have shown to reduce blood pressure, proteinuria, and arterial stiffness. However, more clinical trials are needed, and the results of active or recently concluded studies are eagerly awaited.

Endothelin-1 traps as a potential therapeutic tool: from diabetes to beyond?

There is substantial research on the vasoactive peptide endothelin (ET)-1 in physiology, as well as in pathology. In fact, pathologically elevated levels of ET-1 have been found in several disease states, such as various cardiovascular diseases, different cancers, some neurodegenerative disorders, as well as in diabetes. Here, we describe and discuss ET-1, its importance in different diseases, and the potential therapeutic effects of ET-traps in the treatment of these diseases. Previous in vitro and in vivo research (in the diabetes disease space) demonstrated that ET-traps potently and significantly prevent the induction of different markers of diabetes-related pathology. This included induction of extracellular matrix (ECM) proteins (collagen 4α1 and fibronectin), which are pathologically elevated in diabetes. The ET-traps prevented induction of these and brought a significant return to non-diabetic levels. We also discuss the merits of using ET-traps over the currently used endothelin receptor antagonists (ERAs) and previously used therapeutic antibodies.

Pharmacological Management of Diabetic Nephropathy

INTRODUCTION

Diabetes mellitus (DM) is one of the most common diseases worldwide. Its adverse effects on several body organs, have made treatment of DM a priority. One of the most serious complications of DM is diabetic nephropathy (DN).

OBJECTIVE

The aim of this review is to critically discuss available data on the pharmacological management of DN.

METHODS

A comprehensive review of the literature was performed to identify studies assessing the impact of several drug classes on DN.

RESULTS

Several studies have been conducted in order to find a novel and effective treatment of DN. So far, the cornerstone therapy of DN consists of renin-angiotensin system (RAS) inhibitors, agents that decrease the synthesis of intrarenal angiotensin II or block its receptors. Their antiproteinuric and antihypertensive effects can not only decelerate the progress of DN but prevent its onset as well. Novel antidiabetic drugs, such as sodium-glucose cotransporter 2 inhibitors (SGLT-2i) and glucagon-like peptide- 1 receptor agonists (GLP-1 RA), are promising agents in the therapy of DN, due to their positive effect on renal and cardiovascular adverse events. From lipid-lowering agents, atorvastatin improves DN up to stage 3 and substantially reduces CVD.

CONCLUSION

RAS inhibitors, SGLT-2i and GLP-1 agonists were found to be beneficial for the treatment of DN. Larger renal trials are needed in order to incorporate these drugs into the first line treatment of DN.

Atrasentan alleviates high glucose-induced podocyte injury by the microRNA-21/forkhead box O1 axis

Diabetic nephropathy (DN) is the most common complication of diabetes mellitus. Atrasentan (Atr) has potential therapeutic values for DN. MicroRNAs (miRNAs) function as vital regulators in the pathophysiology of kidney diseases including DN. Our present study aimed to further explore whether Atr could alleviate kidney injury by regulating microRNA-21(miR-21)/forkhead box O1 (FOXO1) in DN mouse models and cell models. Blood glucose concentration and ACR ratio were determined by matching commercial kits. MiR-21 and FOXO1 mRNA level was measured by RT-qPCR assay. Protein levels of FOXO1, LC3Ⅰ, LC3Ⅱ and p62 were measured by western blot assay. Cell apoptotic index was examined by flow cytometry. The interaction of miR-21 and FOXO1 was tested by bioinformatics analysis, luciferase assay and RIP assay. We found that Atr alleviated kidney injury by inhibiting miR-21 expression and promoting autophagy in DN mice. Moreover, miR-21 loss suppressed apoptosis and induced autophagy in high glucose (HG)-treated podocytes. And, Atr inhibited cell apoptosis and improved cell autophagic activity by downregulating miR-21 in HG-cultured podocytes. Moreover, FOXO1 was identified as a target of miR-21. MiR-21 exerted its pro-apoptosis and anti-autophagy effects by targeting FOXO1 in HG-cultured podocytes. Atr enhanced FOXO1 expression by downregulating miR-21 in HG-cultured podocytes. We concluded that Atr mitigated kidney injury in DN mice and alleviated HG-mediated apoptosis increase and autophagy inhibition in podocytes by regulating miR-21/FOXO1 axis, further elucidating the molecular basis by which Atr hampered DN progression.

Cardiovascular Disease and Diabetic Kidney Disease

Diabetic kidney disease commonly is associated with an increased risk of cardiovascular disease. There are traditional common risk factors for both conditions including hypertension and poor glycemic control. However, it is likely that there are other pathophysiological mechanisms that explain the clinical phenomenon of increased cardiovascular disease in diabetic patients with chronic kidney and vice versa. Current management of both conditions includes aggressive glucose and blood pressure control. The protective role of treating dyslipidemia has been shown for cardiovascular disease, but the results for renal disease are not as clear. The advent of new classes of glucose-lowering agents such as sodium glucose co-transporter2 inhibitors and glucagon-like peptide-1 agonists has resulted in impressive effects on both cardiovascular and renal disease in diabetes. However, how these drugs act independently of glucose lowering to confer both kidney and cardiovascular protection has not been fully elucidated. Nevertheless, these new treatments provide optimism for reducing both microvascular and macrovascular complications in diabetes, which represent the major causes of morbidity and premature mortality in this condition.

Transcription profiling of artemisinin-treated diabetic nephropathy rats using high-throughput sequencing

Artemisinin (Art) plays a renoprotective role in diabetic nephropathy (DN) rats. However, the differential gene expression profile and underlying molecular mechanism of Art treatment in DN is not well understood. We constructed an animal model of DN by injection of streptozotocin (STZ) in rats. We then examined the profile of differentially expressed genes following administration of Art using RNA-sequencing (KANGCH&EN, Shanghai, China). Five genes identified by RNA-sequencing were randomly selected and validated by qRT-PCR. Bioinformatic analyses were performed to study these differentially expressed genes. We identified a total of 31 genes that were significantly up-regulated in DN samples compared to both normal and Art treatment samples, and 38 genes that were significantly down-regulated in DN samples compared to both normal and Art treatment samples. The identified genes were associated with a list of gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and may be involved in the mechanism underlying Art treatment of DN. Thus, the results from the current study demonstrate that genes are aberrantly expressed after Art treatment and identify promising targets in the treatment of DN with artemisinin.

A Glimpse of the Mechanisms Related to Renal Fibrosis in Diabetic Nephropathy

Diabetic nephropathy (DN) is a common kidney disease in people with diabetes, which is also a serious microvascular complication of diabetes and the main cause of end-stage renal disease (ESRD) in developed and developing countries. Renal fibrosis is a finally pathological change in DN. Nevertheless, the relevant mechanism of cause to renal fibrosis in DN is still complex. In this review, we summarized that the role of cell growth factors, epithelial-mesenchymal transition (EMT) in the renal fibrosis of DN, we also highlighted the miRNA and inflammatory cells, such as macrophage, T lymphocyte, and mastocyte modulate the progression of DN. In addition, there are certain other mechanisms that may yet be conclusively defined. Recent studies demonstrated that some of the new signaling pathways or molecules, such as Notch, Wnt, mTOR, Epac-Rap-1 pathway, may play a pivotal role in the modulation of ECM accumulation and renal fibrosis in DN. This review aims to elucidate the mechanism of renal fibrosis in DN and has provided new insights into possible therapeutic interventions to inhibit renal fibrosis and delay the development of DN.

New Therapies for the Treatment of Renal Fibrosis

Renal fibrosis is the common pathway for progression of chronic kidney disease (CKD) to end stage of renal disease. It is now widely accepted that the degree of renal fibrosis correlates with kidney function and CKD stages. The key cellular basis of renal fibrosis includes activation of myofibroblasts, excessive production of extracellular matrix components, and infiltration of inflammatory cells. Many cellular mechanisms responsible for renal fibrosis have been identified, and some antifibrotic agents show a greater promise in slowing down and even reversing fibrosis in animal models; however, translating basic findings into effective antifibrotic therapies in human has been limited. In this chapter, we will discuss the effects and mechanisms of some novel antifibrotic agents in both preclinical studies and clinical trials.

Endothelin-receptor antagonists in the management of pulmonary arterial hypertension: where do we stand?

Pulmonary arterial hypertension, a disease largely neglected until a few decades ago, is presently the object of intense studies by several research teams. Despite considerable progress, pulmonary arterial hypertension remains a major clinical problem, because it is not always easy to diagnose, treat, and prevent. The disease was considered incurable until the late 1990s, when Epoprostenol was introduced as the first tool against this illness. More recently, therapy for pulmonary arterial hypertension gained momentum after publication of the SERAPHIN and AMBITION trials, which also highlighted the importance of upfront therapy. This review also focuses on recent substudies from these trials and progress in drugs targeting the endothelin pathway. Future perspectives with regard to endothelin-receptor antagonists are also discussed.

Antibodies targeting human endothelin-1 receptors reveal different conformational states in cancer cells

The endothelin axis (endothelins and their receptors) is strongly involved in physiological and pathological processes. ET-1 plays a crucial role in particular in tumor diseases. Endothelin-1 receptors (ET(A) and ET(B)) are deregulated and overexpressed in several tumors such as melanoma and glioma. We studied the binding of 24 monoclonal antibodies directed against human ET(B) receptors (hET(B)) to different melanoma cell lines. Few of these mAbs bound to all the melanoma cell lines. One of them, rendomab B49, bound to ET(B) receptors expressed at the surface of human glioma stem cells. More recently, we produced new antibodies directed against human ET(A) receptor (hET(A)). Several antibodies have been isolated and have been screened on different tumoral cells lines. As for the mAbs directed against the hET(B) receptor only some of new antibodies directed against ET(A) receptor are capable to bind the human tumoral cell lines. Rendomab A63 directed against hET(A) is one of them. We report the specificity and binding properties of these mAbs and consider their potential use in diagnosis by an in vivo imaging approach.

Endothelin A Receptors Expressed in Renal Blood Vessels of Renal Transplant Patients Are Connected With Acute Tubular Necrosis or Antibody-Mediated Rejection

BACKGROUND

The role of non-HLA antibodies named antiendothelin A receptor antibodies is potentially significant but not established. The significance of the endothelin A receptor (ETAR) and its expression in renal biopsy has not been defined. We decided to evaluate the presence and relevance of ETARs in renal transplant biopsy for cause. The aim of our study was to evaluate the immunoreactivity of the ETAR and its significance in patients who had a renal transplant biopsy due to deterioration of transplant function (biopsy for cause) with detailed characterization of staining in small and intermediate arteries of renal transplant biopsies.

METHODS

Immunohistochemical expression of ETARs was analyzed in 162 renal transplant biopsies. Microscopic evaluation of ETAR expression (polyclonal antibody) was performed on paraffin sections. ETAR expression was analyzed in renal blood vessels (small and intermediate arteries) based on three-step scale.

RESULTS

We analyzed 154 patients who had renal allograft biopsy between 6 days and 24 years (median 597 days) after transplantation. Positive staining of ETAR in small and intermediate arteries was noticed in 9 patients. Among these patients, 4 had early biopsies (<3 months after transplantation), all developed acute tubular necrosis, and 1 developed additionally acute humoral rejection. Further, 4 patients had late biopsy (1-8 years after transplantation) and all developed characteristics of antibody mediated rejection. Lastly, 1 patient had no characteristic changes in the biopsy 4 months after transplantation. Graft loss 1 year after biopsy was higher in patients who were ETAR-positive but statistical significance was not achieved.

CONCLUSIONS

The expression of endothelin receptors in renal blood vessels (small and intermediate arteries) seems to be important in diagnosis of damage during acute tubular necrosis and antibody-mediated rejection.

Renal fibrosis: Recent translational aspects

Renal fibrogenesis is the common final pathway to all renal injuries that consequently leads to Chronic Kidney Disease (CKD). Renal fibrogenesis corresponds to the replacement of renal functional tissue by extra-cellular matrix proteins, mainly collagens, that ultimately impairs kidney function. Blockade of the renin angiotensin system by Angiotensin Converting Enzyme inhibitors (ACEi) or Angiotensin Receptor Blockers (ARBs) was the first strategy that proved efficient to blunt the development of renal fibrogenesis independently of its systemic action on blood pressure. Although this strategy has been published 20years ago, there is to date no novel therapeutic targets that are both safe and efficient in hindering renal fibrogenesis and CKD in humans, nor there is any new biomarker to precisely quantify this process. In our review, we will focus on the most recent pathways leading to fibrogenesis which have a high therapeutic potential in humans and on the most promising biomarkers of renal fibrosis.