Avosentan for overt diabetic nephropathy

Combination therapy for kidney disease in people with diabetes mellitus

Diabetic kidney disease (DKD), defined as co-existing diabetes and chronic kidney disease in the absence of other clear causes of kidney injury, occurs in approximately 20-40% of patients with diabetes mellitus. As the global prevalence of diabetes has increased, DKD has become highly prevalent and a leading cause of kidney failure, accelerated cardiovascular disease, premature mortality and global health care expenditure. Multiple pathophysiological mechanisms contribute to DKD, and single lifestyle or pharmacological interventions have shown limited efficacy at preserving kidney function. For nearly two decades, renin-angiotensin system inhibitors were the only available kidney-protective drugs. However, several new drug classes, including sodium glucose cotransporter-2 inhibitors, a non-steroidal mineralocorticoid antagonist and a selective endothelin receptor antagonist, have now been demonstrated to improve kidney outcomes in people with type 2 diabetes mellitus. In addition, emerging preclinical and clinical evidence of the kidney-protective effects of glucagon-like-peptide-1 receptor agonists has led to the prospective testing of these agents for DKD. Research and clinical efforts are geared towards using therapies with potentially complementary efficacy in combination to safely halt kidney disease progression. As more kidney-protective drugs become available, the outlook for people living with DKD should improve in the next few decades.

Mechanism of protective actions of sparsentan in the kidney: lessons from studies in models of chronic kidney disease

Simultaneous inhibition of angiotensin II AT1 and endothelin ETA receptors has emerged as a promising approach for treatment of chronic progressive kidney disease. This therapeutic approach has been advanced by the introduction of sparsentan, the first dual AT1 and ETA receptor antagonist. Sparsentan is a single molecule with high affinity for both receptors. It is US Food and Drug Administration approved for immunoglobulin A nephropathy (IgAN) and is currently being developed as a treatment for rare kidney diseases, such as focal segmental glomerulosclerosis. Clinical studies have demonstrated the efficacy and safety of sparsentan in these conditions. In parallel with clinical development, studies have been conducted to elucidate the mechanisms of action of sparsentan and its position in the context of published evidence characterizing the nephroprotective effects of dual ETA and AT1 receptor inhibition. This review summarizes this evidence, documenting beneficial anti-inflammatory, antifibrotic, and hemodynamic actions of sparsentan in the kidney and protective actions in glomerular endothelial cells, mesangial cells, the tubulointerstitium, and podocytes, thus providing the rationale for the use of sparsentan as therapy for focal segmental glomerulosclerosis and IgAN and suggesting potential benefits in other renal diseases, such as Alport syndrome.

Sparsentan for Focal Segmental Glomerulosclerosis in the DUET Open-Label Extension: Long-term Efficacy and Safety

Rationale & Objective

Sparsentan is a novel, non-immunosuppressive, single-molecule, dual endothelin angiotensin receptor antagonist (DEARA) examined in the ongoing phase 2 DUET trial for focal segmental glomerulosclerosis (FSGS). In the DUET 8-week double-blind period, sparsentan resulted in greater proteinuria reduction versus irbesartan. We report the long-term efficacy and safety of sparsentan during the open-label extension over more than 4 years.

Study Design

Patients were examined from their first sparsentan dose (double-blind period or open-label extension) through 4.6 years.

Setting & Participants

Patients with FSGS, excluding secondary FSGS.

Intervention

Sparsentan (200, 400, and 800 mg/d).

Outcomes

Urinary protein-creatinine ratio, FSGS partial remission endpoint (urinary protein-creatinine ratio ≤1.5 g/g and >40% reduction from baseline), estimated glomerular filtration rate, and blood pressure approximately every 12 weeks. Treatment-emergent adverse events by year and cases/100 patient-years.

Results

109 patients were enrolled; 108 received ≥1 sparsentan dose; 103 entered the open-label extension (68 sparsentan, 35 irbesartan during the double-blind period). Sparsentan was ongoing in 45/108 patients (41.7%); median time to treatment discontinuation was 3.9 years (95% CI, 2.6-5.2). Mean percent proteinuria reduction from baseline was sustained through follow-up. Achieving partial remission within 9 months of first sparsentan dose (52.8% of patients) versus not achieving (47.2%) was associated with significantly slower rate of estimated glomerular filtration rate decline over the entire treatment period (-2.70 vs -6.56; P = 0.03) and in the first 2 years (-1.69 vs -6.46; P = 0.03). The most common treatment-emergent adverse events (>9 cases/100 patient-years) were headache, peripheral edema, upper respiratory infection, hyperkalemia, and hypotension. Peripheral edema and hypotension declined from year 1 (13.9% and 15.7% of patients, respectively) to ≤4% in years ≥2. There were no cases of heart failure and no patient deaths.

Limitations

The open-label extension does not include a comparison group.

Conclusions

Long-term sparsentan treatment showed sustained proteinuria reduction and a consistent safety profile.

Molecular Targets of Novel Therapeutics for Diabetic Kidney Disease: A New Era of Nephroprotection

Diabetic kidney disease (DKD) is a chronic microvascular complication in patients with diabetes mellitus (DM) and the leading cause of end-stage kidney disease (ESKD). Although glomerulosclerosis, tubular injury and interstitial fibrosis are typical damages of DKD, the interplay of different processes (metabolic factors, oxidative stress, inflammatory pathway, fibrotic signaling, and hemodynamic mechanisms) appears to drive the onset and progression of DKD. A growing understanding of the pathogenetic mechanisms, and the development of new therapeutics, is opening the way for a new era of nephroprotection based on precision-medicine approaches. This review summarizes the therapeutic options linked to specific molecular mechanisms of DKD, including renin-angiotensin-aldosterone system blockers, SGLT2 inhibitors, mineralocorticoid receptor antagonists, glucagon-like peptide-1 receptor agonists, endothelin receptor antagonists, and aldosterone synthase inhibitors. In a new era of nephroprotection, these drugs, as pillars of personalized medicine, can improve renal outcomes and enhance the quality of life for individuals with DKD.

Endothelin System in Hypertension and Chronic Kidney Disease

ET (endothelin) is a powerful vasoconstrictor 21-amino acid peptide present in many tissues, which exerts many physiological functions across the body and participates as a mediator in many pathological conditions. ETs exert their effects through ETA and ETB receptors, which can be blocked by selective receptor antagonists. ETs were shown to play important roles among others, in systemic hypertension, particularly when resistant or difficult to control, and in pulmonary hypertension, atherosclerosis, cardiac hypertrophy, subarachnoid hemorrhage, chronic kidney disease, diabetic cardiovascular disease, scleroderma, some cancers, etc. To date, ET antagonists are only approved for the treatment of primary pulmonary hypertension and recently for IgA nephropathy and used in the treatment of digital ulcers in scleroderma. However, they may soon be approved for the treatment of patients with resistant hypertension and different types of nephropathy. Here, the role of ETs is reviewed with a special emphasis on participation in and treatment of hypertension and chronic kidney disease.

Endothelin receptor antagonists in diabetic and non-diabetic chronic kidney disease

Chronic kidney disease (CKD) is one of the major causes of morbidity and mortality, affecting >800 million persons globally. While we still lack efficient, targeted therapies addressing the major underlying pathophysiologic processes in CKD, findings of several recent trials have brought about a shifting landscape of promising therapies. The endothelin system has been implicated in the pathophysiology of CKD and endothelin receptor antagonists are one class of drugs for which we have increasing evidence of efficacy in these patients. In this review we summarize the most recent findings on the safety and efficacy of endothelin receptor antagonists in diabetic and non-diabetic CKD, future directions of research and upcoming treatments.

Investigational new drugs for the treatment of chronic renal failure: an overview of the literature

INTRODUCTION

Chronic kidney disease (CKD) is widespread throughout the world, with a high social and health impact. It is considered a 'silent killer' for its sudden onset without symptoms in the early stages of the disease. The main goal of nephrologists is to slow the progression of kidney disease and treat the associated symptoms with a range of new medications.

AREAS COVERED

The aim of this systematic review is to analyze the new investigational drugs for the treatment of chronic renal failure. Data were obtained from the available scientific literature and from the ClinicalTrials.gov website.

EXPERT OPINION

Among the drugs currently being researched, SGLT2 inhibitors appear to be the most promising drugs for the treatment of CKD, has they have slower progression of CKD and protection of cardiorenal function. An important role in the future of CKD treatment is played by autologous cell-therapy, which appears to be a new frontier in the treatment of CKD. Other therapeutic strategies are currently being investigated and have been shown to slow the progression of CKD. However, further studies are needed to determine whether these approaches may offer benefits in slowing the progression of CKD in the near future.

Focal Segmental Glomerulosclerosis Patient Baseline Characteristics in the Sparsentan Phase 3 DUPLEX Study

Introduction

The phase 3 DUPLEX trial is evaluating sparsentan, a novel, nonimmunosuppressive, single-molecule dual endothelin angiotensin receptor antagonist, in patients with focal segmental glomerulosclerosis (FSGS).

Methods

DUPLEX (NCT03493685) is a global, multicenter, randomized, double-blind, parallel-group, active-controlled study evaluating the efficacy and safety of sparsentan 800 mg once daily versus irbesartan 300 mg once daily in patients aged 8 to 75 years (USA/UK) and 18 to 75 years (ex-USA/UK) weighing ≥20 kg with biopsy-proven FSGS or documented genetic mutation in a podocyte protein associated with FSGS, and urine protein-to-creatinine ratio (UP/C) ≥1.5 g/g. Baseline characteristics blinded to treatment allocation are reported descriptively.

Results

The primary analysis population includes 371 patients (336 adult, 35 pediatric [<18 years]) who were randomized and received study drug (median age, 42 years). Patients were White (73.0%), Asian (13.2%), Black/African American (6.7%), or Other race (7.0%); and from North America (38.8%), Europe (36.1%), South America (12.7%), or Asia Pacific (12.4%). Baseline median UP/C was 3.0 g/g; 42.6% in nephrotic-range (UP/C >3.5 g/g [adults]; >2.0 g/g [pediatrics]). Patients were evenly distributed across estimated glomerular filtration rate (eGFR) categories corresponding to chronic kidney disease (CKD) stages 1 to 3b. Thirty-three patients (9.4% of 352 evaluable samples) had pathogenic or likely pathogenic (P/LP) variants of genes essential to podocyte structural integrity and function, 27 (7.7%) had P/LP collagen gene (COL4A3/4/5) variants, and 14 (4.0%) had high-risk APOL1 genotypes.

Conclusions

Patient enrollment in DUPLEX, the largest interventional study in FSGS to date, will enable important characterization of the treatment effect of sparsentan in a geographically broad and clinically diverse FSGS population.

Efficacy and safety of zibotentan and dapagliflozin in patients with chronic kidney disease: study design and baseline characteristics of the ZENITH-CKD trial

BACKGROUND

Sodium-glucose co-transporter 2 inhibitors (SGLT2is) are part of the standard of care for patients with chronic kidney disease (CKD), both with and without type 2 diabetes. Endothelin A (ETA) receptor antagonists have also been shown to slow progression of CKD. Differing mechanisms of action of SGLT2 and ETA receptor antagonists may enhance efficacy. We outline a study to evaluate the effect of combination zibotentan/dapagliflozin versus dapagliflozin alone on albuminuria and estimated glomerular filtration rate (eGFR).

METHODS

We are conducting a double-blind, active-controlled, Phase 2b study to evaluate the efficacy and safety of ETA receptor antagonist zibotentan and SGLT2i dapagliflozin in a planned 415 adults with CKD (Zibotentan and Dapagliflozin for the Treatment of CKD; ZENITH-CKD). Participants are being randomized (1:2:2) to zibotentan 0.25 mg/dapagliflozin 10 mg once daily (QD), zibotentan 1.5 mg/dapagliflozin 10 mg QD and dapagliflozin 10 mg QD alone, for 12 weeks followed by a 2-week off-treatment wash-out period. The primary endpoint is the change in log-transformed urinary albumin-to-creatinine ratio (UACR) from baseline to Week 12. Other outcomes include change in blood pressure from baseline to Week 12 and change in eGFR the study. The incidence of adverse events will be monitored. Study protocol-defined events of special interest include changes in fluid-related measures (weight gain or B-type natriuretic peptide).

RESULTS

A total of 447 patients were randomized and received treatment in placebo/dapagliflozin (n = 177), zibotentan 0.25 mg/dapagliflozin (n = 91) and zibotentan 1.5 mg/dapagliflozin (n =  179). The mean age was 62.8 years, 30.9% were female and 68.2% were white. At baseline, the mean eGFR of the enrolled population was 46.7 mL/min/1.73 m2 and the geometric mean UACR was 538.3 mg/g.

CONCLUSION

This study evaluates the UACR-lowering efficacy and safety of zibotentan with dapagliflozin as a potential new treatment for CKD. The study will provide information about an effective and safe zibotentan dose to be further investigated in a Phase 3 clinical outcome trial.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04724837.

Parallelism and non-parallelism in diabetic nephropathy and diabetic retinopathy

Diabetic nephropathy (DN) and diabetic retinopathy (DR), as microvascular complications of diabetes mellitus, are currently the leading causes of end-stage renal disease (ESRD) and blindness, respectively, in the adult working population, and they are major public health problems with social and economic burdens. The parallelism between the two in the process of occurrence and development manifests in the high overlap of disease-causing risk factors and pathogenesis, high rates of comorbidity, mutually predictive effects, and partial concordance in the clinical use of medications. However, since the two organs, the eye and the kidney, have their unique internal environment and physiological processes, each with specific influencing molecules, and the target organs have non-parallelism due to different pathological changes and responses to various influencing factors, this article provides an overview of the parallelism and non-parallelism between DN and DR to further recognize the commonalities and differences between the two diseases and provide references for early diagnosis, clinical guidance on the use of medication, and the development of new drugs.

Taming resistant hypertension: The promise of novel pharmacologic approaches and renal denervation

Resistant hypertension is associated with an exceedingly high cardiovascular risk and there remains an unmet therapeutic need driven by pathophysiologic pathways unaddressed by guideline-recommended therapy. While spironolactone is widely considered as the preferable fourth-line drug, its broad application is limited by its side effect profile, especially off-target steroid receptor-mediated effects and hyperkalaemia in at-risk subpopulations. Recent landmark trials have reported promising safety and efficacy results for a number of novel compounds targeting relevant pathophysiologic pathways that remain unopposed by contemporary drugs. These include the dual endothelin receptor antagonist, aprocitentan, the aldosterone synthase inhibitor, baxdrostat and the nonsteroidal mineralocorticoid receptor antagonist finerenone. Furthermore, the evidence base for consideration of catheter-based renal denervation as a safe and effective adjunct therapeutic approach across the clinical spectrum of hypertension has been further substantiated. This review will summarise the recently published evidence on novel antihypertensive drugs and renal denervation in the context of resistant hypertension.

Dual soluble epoxide hydrolase inhibitor - farnesoid X receptor agonist interventional treatment attenuates renal inflammation and fibrosis

Introduction

Renal fibrosis associated with inflammation is a critical pathophysiological event in chronic kidney disease (CKD). We have developed DM509 which acts concurrently as a farnesoid X receptor agonist and a soluble epoxide hydrolase inhibitor and investigated DM509 efficacy as an interventional treatment using the unilateral ureteral obstruction (UUO) mouse model.

Methods

Male mice went through either UUO or sham surgery. Interventional DM509 treatment (10mg/kg/d) was started three days after UUO induction and continued for 7 days. Plasma and kidney tissue were collected at the end of the experimental protocol.

Results

UUO mice demonstrated marked renal fibrosis with higher kidney hydroxyproline content and collagen positive area. Interventional DM509 treatment reduced hydroxyproline content by 41% and collagen positive area by 65%. Renal inflammation was evident in UUO mice with elevated MCP-1, CD45-positive immune cell positive infiltration, and profibrotic inflammatory gene expression. DM509 treatment reduced renal inflammation in UUO mice. Renal fibrosis in UUO was associated with epithelial-to-mesenchymal transition (EMT) and DM509 treatment reduced EMT. UUO mice also had tubular epithelial barrier injury with increased renal KIM-1, NGAL expression. DM509 reduced tubular injury markers by 25-50% and maintained tubular epithelial integrity in UUO mice. Vascular inflammation was evident in UUO mice with 9 to 20-fold higher ICAM and VCAM gene expression which was reduced by 40-50% with DM509 treatment. Peritubular vascular density was reduced by 35% in UUO mice and DM509 prevented vascular loss.

Discussion

Interventional treatment with DM509 reduced renal fibrosis and inflammation in UUO mice demonstrating that DM509 is a promising drug that combats renal epithelial and vascular pathological events associated with progression of CKD.

Initial real-world experience of clazosentan for subarachnoid hemorrhage in Japan

BACKGROUND

Cerebral vasospasm (CVS) is one of the most critical factors associated with clinical outcomes of patients with subarachnoid hemorrhage (SAH). Clazosentan has been investigated worldwide as a prophylactic agent to prevent CVS. We evaluated a new CVS management protocol which included clazosentan.

METHODS

Consecutive 138 patients with SAH, hospitalized in our institution between January 2017 and December 2022, were included in this study. Baseline characteristics, clinical findings, and operative records were analyzed retrospectively. From May 2022, 10 mg/h clazosentan was co-administered with fasudil to all patients according to the indication in the Japanese label. Patients admitted before this date received the conventional combined protocol using the fasudil hydrochloride, nicardipine, and ozagrel.

RESULTS

Eighteen (13.0%) patients received the new protocol during the CVS period (defined as day 1 up to day 14 after SAH onset). There were 54 (39.1%) elderly patients aged 75 years or older. Seventy-two (52.2%) patients underwent neurosurgical clipping, whereas 55 (39.9%) patients received endovascular coiling. Among the patients with new protocol, only one patient (5.6%) had symptomatic CVS, compared with 18 patients (15.0%) in those with conventional protocol. More patients who received the new protocol had fluid retention compared with control group (38.9% [7/18] vs. 8.3% [10/120]). Other results did not differ between the two groups.

CONCLUSIONS

Clinical outcomes of the new protocol were comparable to those of conventional protocol. Clazosentan may simplify anti-vasospasm treatment. Fluid retention was a specific side-effect of clazosentan, which requires attention especially in the first half of the CVS period.

Novel pharmacological interventions for diabetic kidney disease

PURPOSE OF REVIEW

The purpose of this review is to summarize the latest evidence on the prevention and progression of diabetic kidney disease (DKD), as well as novel pharmacological interventions from preclinical and early clinical studies with promising findings in the reduction of this condition's burden.

RECENT FINDINGS

We will cover the latest evidence on the reduction of proteinuria and kidney function decline in DKD achieved through established renin-angiotensin-aldosterone system (RAAS) system blockade and the more recent addition of SGLT2i, nonsteroidal mineralocorticoid receptor antagonists (MRAs) and GLP1-RA, that combined will most likely integrate the mainstay for current DKD treatment. We also highlight evidence from new mechanisms of action in DKD, including other haemodynamic anti-inflammatory and antifibrotic interventions, oxidative stress modulators and cell identity and epigenetic targets.

SUMMARY

Renal specific outcome trials have become more popular and are increasing the available armamentarium to diminish the progression of renal decline in patients at greater risk of end-stage kidney disease (ESKD) such as diabetic individuals. A combined pharmaceutical approach based on available rigorous studies should include RAAS blockade, SGLT2 inhibitors, nonsteroidal MRA and expectedly GLP1-RA on a personalized based-intervention. New specific trials designed to address renal outcomes will be needed for innovative therapies to conclude on their potential benefits in DKD.

Sparsentan versus Irbesartan in Focal Segmental Glomerulosclerosis

BACKGROUND

An unmet need exists for focal segmental glomerulosclerosis (FSGS) treatment. In an 8-week, phase 2 trial, sparsentan, a dual endothelin-angiotensin receptor antagonist, reduced proteinuria in patients with FSGS. The efficacy and safety of longer-term treatment with sparsentan for FSGS are unknown.

METHODS

In this phase 3 trial, we enrolled patients with FSGS (without known secondary causes) who were 8 to 75 years of age; patients were randomly assigned to receive sparsentan or irbesartan (active control) for 108 weeks. The surrogate efficacy end point assessed at the prespecified interim analysis at 36 weeks was the FSGS partial remission of proteinuria end point (defined as a urinary protein-to-creatinine ratio of ≤1.5 [with protein and creatinine both measured in grams] and a >40% reduction in the ratio from baseline). The primary efficacy end point was the estimated glomerular filtration rate (eGFR) slope at the time of the final analysis. The change in eGFR from baseline to 4 weeks after the end of treatment (week 112) was a secondary end point. Safety was also evaluated.

RESULTS

A total of 371 patients underwent randomization: 184 were assigned to receive sparsentan and 187 to receive irbesartan. At 36 weeks, the percentage of patients with partial remission of proteinuria was 42.0% in the sparsentan group and 26.0% in the irbesartan group (P = 0.009), a response that was sustained through 108 weeks. At the time of the final analysis at week 108, there were no significant between-group differences in the eGFR slope; the between-group difference in total slope (day 1 to week 108) was 0.3 ml per minute per 1.73 m2 of body-surface area per year (95% confidence interval [CI], -1.7 to 2.4), and the between-group difference in the slope from week 6 to week 108 (i.e., chronic slope) was 0.9 ml per minute per 1.73 m2 per year (95% CI, -1.3 to 3.0). The mean change in eGFR from baseline to week 112 was -10.4 ml per minute per 1.73 m2 with sparsentan and -12.1 ml per minute per 1.73 m2 with irbesartan (difference, 1.8 ml per minute per 1.73 m2; 95% CI, -1.4 to 4.9). Sparsentan and irbesartan had similar safety profiles, and the frequency of adverse events was similar in the two groups.

CONCLUSIONS

Among patients with FSGS, there were no significant between-group differences in eGFR slope at 108 weeks, despite a greater reduction in proteinuria with sparsentan than with irbesartan. (Funded by Travere Therapeutics; DUPLEX ClinicalTrials.gov number, NCT03493685.).

Treatment and practical considerations of diabetic kidney disease

Diabetic kidney disease (DKD) is a complication of diabetes that can lead to kidney failure. Over the years, several drugs have been developed to combat this disease. In the early 90s, angiotensin blockade (ACEi and ARBs) was introduced, which revolutionized the treatment of DKD. In recent years, newer drugs such as sodium-glucose co-transporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, endothelin antagonists, and mineralocorticoid receptor antagonists (MRA) have shown great promise in reducing albuminuria and protecting the kidneys. These drugs are being used in combination with lifestyle modifications, patient education, and risk factor modification to effectively manage DKD. In this review, we will explore the latest pharmacological options, their efficacy, and their potential to revolutionize the management of this debilitating disease.

Impact of Finerenone-Induced Albuminuria Reduction on Chronic Kidney Disease Outcomes in Type 2 Diabetes : A Mediation Analysis

BACKGROUND

In patients with chronic kidney disease (CKD) and type 2 diabetes (T2D), finerenone, a nonsteroidal mineralocorticoid receptor antagonist, reduces cardiovascular and kidney failure outcomes. Finerenone also lowers the urine albumin-to-creatinine ratio (UACR). Whether finerenone-induced change in UACR mediates cardiovascular and kidney failure outcomes is unknown.

OBJECTIVE

To quantify the proportion of kidney and cardiovascular risk reductions seen over a 4-year period mediated by a change in kidney injury, as measured by the change in log UACR between baseline and month 4.

DESIGN

Post hoc mediation analysis using pooled data from 2 phase 3, double-blind trials of finerenone. (ClinicalTrials.gov: NCT02540993 and NCT02545049).

SETTING

Several clinical sites in 48 countries.

PATIENTS

12 512 patients with CKD and T2D.

INTERVENTION

Finerenone and placebo (1:1).

MEASUREMENTS

Separate mediation analyses were done for the composite kidney (kidney failure, sustained ≥57% decrease in estimated glomerular filtration rate from baseline [approximately a doubling of serum creatinine], or kidney disease death) and cardiovascular (cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure) outcomes.

RESULTS

At baseline, median UACR was 514 mg/g. A 30% or greater reduction in UACR was seen in 3338 (53.2%) patients in the finerenone group and 1684 (27.0%) patients in the placebo group. Reduction in UACR (analyzed as a continuous variable) mediated 84% and 37% of the treatment effect on the kidney and cardiovascular outcomes, respectively. When change in UACR was analyzed as a binary variable (that is, whether the guideline-recommended 30% reduction threshold was met), the proportions mediated for each outcome were 64% and 26%, respectively.

LIMITATION

The current findings are not readily extendable to other drugs.

CONCLUSION

In patients with CKD and T2D, early albuminuria reduction accounted for a large proportion of the treatment effect against CKD progression and a modest proportion of the effect against cardiovascular outcomes.

PRIMARY FUNDING SOURCE

Bayer AG.

Pathomechanisms of Diabetic Kidney Disease

The worldwide occurrence of diabetic kidney disease (DKD) is swiftly rising, primarily attributed to the growing population of individuals affected by type 2 diabetes. This surge has been transformed into a substantial global concern, placing additional strain on healthcare systems already grappling with significant demands. The pathogenesis of DKD is intricate, originating with hyperglycemia, which triggers various mechanisms and pathways: metabolic, hemodynamic, inflammatory, and fibrotic which ultimately lead to renal damage. Within each pathway, several mediators contribute to the development of renal structural and functional changes. Some of these mediators, such as inflammatory cytokines, reactive oxygen species, and transforming growth factor β are shared among the different pathways, leading to significant overlap and interaction between them. While current treatment options for DKD have shown advancement over previous strategies, their effectiveness remains somewhat constrained as patients still experience residual risk of disease progression. Therefore, a comprehensive grasp of the molecular mechanisms underlying the onset and progression of DKD is imperative for the continued creation of novel and groundbreaking therapies for this condition. In this review, we discuss the current achievements in fundamental research, with a particular emphasis on individual factors and recent developments in DKD treatment.

Zibotentan in combination with dapagliflozin compared with dapagliflozin in patients with chronic kidney disease (ZENITH-CKD): a multicentre, randomised, active-controlled, phase 2b, clinical trial

BACKGROUND

In patients with chronic kidney disease, SGLT2 inhibitors and endothelin A receptor antagonists (ERAs) can reduce albuminuria and glomerular filtration rate (GFR) decline. We assessed the albuminuria-lowering efficacy and safety of the ERA zibotentan combined with the SGLT2 inhibitor dapagliflozin.

METHODS

ZENITH-CKD was a multicentre, randomised, double-blind, active-controlled clinical trial, done in 170 clinical practice sites in 18 countries. Adults (≥18 to ≤90 years) with an estimated GFR (eGFR) of 20 mL/min per 1·73 m2 or greater and a urinary albumin-to-creatinine ratio (UACR) of 150-5000 mg/g were randomly assigned (2:1:2) to 12 weeks of daily treatment with zibotentan 1·5 mg plus dapagliflozin 10 mg, zibotentan 0·25 mg plus dapagliflozin 10 mg, or dapagliflozin 10 mg plus placebo, as adjunct to angiotensin-converting enzyme inhibitors or angiotensin receptor blockers if tolerated. The primary endpoint was a change from baseline in log-transformed UACR (zibotentan 1·5 mg plus dapagliflozin vs dapagliflozin plus placebo) at week 12. Fluid retention was an event of special interest, defined as an increase in bodyweight of at least 3% (at least 2·5% must have been from total body water) from baseline or an increase of at least 100% in B-type natriuretic peptide (BNP) and either a BNP concentration greater than 200 pg/mL if without atrial fibrillation or BNP greater than 400 pg/mL if with atrial fibrillation. This trial is registered with ClinicalTrials.gov, NCT04724837, and is completed.

FINDINGS

Between April 28, 2021, and Jan 17, 2023, we assessed 1492 participants for eligibility. For the main analysis, we randomly assigned 449 (30%) participants, 447 (99%) of whom (mean age 62·8 years [SD 12·1], 138 [31%] female, 309 [69%] male, 305 [68%] White, mean eGFR 46·7 mL/min per 1·73 m2 [SD 22·4], and median UACR 565·5 mg/g [IQR 243·0-1212·6]) received treatment with zibotentan 1·5 mg plus dapagliflozin (n=179 [40%]), zibotentan 0·25 mg plus dapagliflozin (n=91 [20%]), or dapagliflozin plus placebo (n=177 [40%]). Zibotentan 1·5 mg plus dapagliflozin and zibotentan 0·25 mg plus dapagliflozin reduced UACR versus dapagliflozin plus placebo throughout the treatment period of the study. At week 12, the difference in UACR versus dapagliflozin plus placebo was -33·7% (90% CI -42·5 to -23·5; p<0·0001) for zibotentan 1·5 mg plus dapagliflozin and -27·0% (90% CI -38·4 to -13·6; p=0·0022) for zibotentan 0·25 mg plus dapagliflozin. Fluid-retention events were observed in 33 (18%) of 179 participants in the zibotentan 1·5 mg plus dapagliflozin group, eight (9%) of 91 in the zibotentan 0·25 mg plus dapagliflozin group, and 14 (8%) of 177 in the dapagliflozin plus placebo group.

INTERPRETATION

Zibotentan combined with dapagliflozin reduced albuminuria with an acceptable tolerability and safety profile and is an option to reduce chronic kidney disease progression in patients already receiving currently recommended therapy.

FUNDING

AstraZeneca.

New Potential Treatments for Resistant Hypertension

PURPOSE OF REVIEW

To provide an update and review approaches to the treatment of resistant hypertension (RH) with a focus on emerging potential therapies.

RECENT FINDINGS

Resistant hypertension is defined as a blood pressure that remains elevated above a patient's individualized target despite the concurrent use of 3 antihypertensive agents of different classes including a diuretic or use of 4 or more antihypertensive agents. Patients with RH have an increased risk of adverse cardiovascular and renal outcomes. Most RH is attributed to apparent RH and is not true RH. True RH is a diagnosis of exclusion after apparent RH has been excluded. Treatment of RH is challenging, and blood pressure goal is often difficult to achieve. Currently several new therapies have emerged with forthcoming data that provide promise for improved blood pressure control in those with resistant hypertension. Once RH has been diagnosed, patients should be on standardized therapy that includes agents from three different classes including a diuretic with addition in most cases of a mineralocorticoid as a fourth line agent. There are newer agents in development currently being studied in clinical trials including dual endothelin receptor antagonists and aldosterone synthase inhibitors that appear to be efficacious. Other approved medications including SGLT2 inhibitors and non-steroidal mineralocorticoids such as finerenone also need to be incorporated into treatment paradigms. Renal denervation with catheter based devices is another potential promising treatment option in this population.

Role of hypertension in progression of pediatric CKD

Hypertension is frequent in children with chronic kidney disease (CKD). Its prevalence varies according to CKD stage and cause. It is relatively uncommon in children with congenital kidney disease, while acquired kidney disease is associated with a higher prevalence of hypertension. Studies in children with CKD utilizing ambulatory blood pressure monitoring also showed a high prevalence of masked hypertension. Uncontrolled and longstanding hypertension in children is associated with progression of CKD. Aggressive treatment of high blood pressure should be an essential part of care to delay CKD progression in children.

Common mechanisms underlying diabetic vascular complications: focus on the interaction of metabolic disorders, immuno-inflammation, and endothelial dysfunction

Diabetic vascular complications (DVCs), including macro- and micro- angiopathy, account for a high percentage of mortality in patients with diabetes mellitus (DM). Endothelial dysfunction is the initial and role step for the pathogenesis of DVCs. Hyperglycemia and lipid metabolism disorders contribute to endothelial dysfunction via direct injury of metabolism products, crosstalk between immunity and inflammation, as well as related interaction network. Although physiological and phenotypic differences support their specified changes in different targeted organs, there are still several common mechanisms underlying DVCs. Also, inhibitors of these common mechanisms may decrease the incidence of DVCs effectively. Thus, this review may provide new insights into the possible measures for the secondary prevention of DM. And we discussed the current limitations of those present preventive measures in DVCs research. Video Abstract.

Obstructive nephropathy and molecular pathophysiology of renal interstitial fibrosis

The kidneys play a key role in maintaining total body homeostasis. The complexity of this task is reflected in the unique architecture of the organ. Ureteral obstruction greatly affects renal physiology by altering hemodynamics, changing glomerular filtration and renal metabolism, and inducing architectural malformations of the kidney parenchyma, most importantly renal fibrosis. Persisting pathological changes lead to chronic kidney disease, which currently affects ∼10% of the global population and is one of the major causes of death worldwide. Studies on the consequences of ureteral obstruction date back to the 1800s. Even today, experimental unilateral ureteral obstruction (UUO) remains the standard model for tubulointerstitial fibrosis. However, the model has certain limitations when it comes to studying tubular injury and repair, as well as a limited potential for human translation. Nevertheless, ureteral obstruction has provided the scientific community with a wealth of knowledge on renal (patho)physiology. With the introduction of advanced omics techniques, the classical UUO model has remained relevant to this day and has been instrumental in understanding renal fibrosis at the molecular, genomic, and cellular levels. This review details key concepts and recent advances in the understanding of obstructive nephropathy, highlighting the pathophysiological hallmarks responsible for the functional and architectural changes induced by ureteral obstruction, with a special emphasis on renal fibrosis.

Diabetic Nephropathy: Update on Pillars of Therapy Slowing Progression

Management of diabetic kidney disease (DKD) has evolved in parallel with our growing understanding of the multiple interrelated pathophysiological mechanisms that involve hemodynamic, metabolic, and inflammatory pathways. These pathways and others play a vital role in the initiation and progression of DKD. Since its initial discovery, the blockade of the renin-angiotensin system has remained a cornerstone of DKD management, leaving a large component of residual risk to be dealt with. The advent of sodium-glucose cotransporter 2 inhibitors followed by nonsteroidal mineralocorticoid receptor antagonists and, to some extent, glucagon-like peptide 1 receptor agonists (GLP-1 RAs) has ushered in a resounding paradigm shift that supports a pillared approach in maximizing treatment to reduce outcomes. This pillared approach is like that derived from the approach to heart failure treatment. The approach mandates that all agents that have been shown in clinical trials to reduce cardiovascular outcomes and/or mortality to a greater extent than a single drug class alone should be used in combination. In this way, each drug class focuses on a specific aspect of the disease's pathophysiology. Thus, in heart failure, β-blockers, sacubitril/valsartan, a mineralocorticoid receptor antagonist, and a diuretic are used together. In this article, we review the evolution of the pillar concept of therapy as it applies to DKD and discuss how it should be used based on the outcome evidence. We also discuss the exciting possibility that GLP-1 RAs may be an additional pillar in the quest to further slow kidney disease progression in diabetes.

Intrarenal Mechanisms of Sodium-Glucose Cotransporter-2 Inhibitors on Tubuloglomerular Feedback and Natriuresis

When sodium-glucose cotransporter-2 (SGLT2) inhibitors were first introduced a decade ago, no one expected them to have substantial effects beyond their known glucose-lowering effects, until the emergence of evidence of their robust renal and cardiovascular benefits showing that they could attenuate progression of kidney disease, irrespective of diabetes, as well as prevent the development of acute kidney injury. Still, the precise and elaborate mechanisms underlying the major organ protection of SGLT2 inhibitors remain unclear. SGLT2 inhibitors inhibit the reabsorption of sodium and glucose in the proximal tubule of the kidney and then recovers tubuloglomerular feedback, whereby SGLT2 inhibitors reduce glomerular hyperfiltration. This simple demonstration of their beneficial effects has perplexed experts in seeking more plausible and as yet undisclosed explanations for the whole effects of SGLT2 inhibitors, including metabolism reprogramming and the modulation of hypoxia, inflammation, and oxidative stress. Given that the renal benefits of SGLT2 inhibitors in patients with kidney disease but without diabetes were comparable to those seen in patients with diabetes, it may be reasonable to keep the emphasis on their hemodynamic actions. In this context, the aim of the present review is to provide a comprehensive overview of renal hemodynamics in individuals with diabetes who are treated with SGLT2 inhibitors, with a focus on natriuresis associated with the regulation of tubuloglomerular feedback and potential aquaresis. Throughout the discussion of alterations in renal sodium and water transports, particular attention will be given to the potential enhancement of adenosine and its receptors following SGLT2 inhibition.

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.

Cardiorenal syndrome and diabetes: an evil pairing

Cardiorenal syndrome (CRS) is a pathology where the heart and kidney are involved, and the deterioration of one of them leads to the malfunction of the other. Diabetes mellitus (DM) carries a higher risk of HF and a worse prognosis. Furthermore, almost half of people with DM will have chronic kidney disease (CKD), which means that DM is the main cause of kidney failure. The triad of cardiorenal syndrome and diabetes is known to be associated with increased risk of hospitalization and mortality. Cardiorenal units, with a multidisciplinary team (cardiologist, nephrologist, nursing), multiple tools for diagnosis, as well as new treatments that help to better control cardio-renal-metabolic patients, offer holistic management of patients with CRS. In recent years, the appearance of drugs such as sodium-glucose cotransporter type 2 inhibitors, have shown cardiovascular benefits, initially in patients with type 2 DM and later in CKD and heart failure with and without DM2, offering a new therapeutic opportunity, especially for cardiorenal patients. In addition, glucagon-like peptide-1 receptor agonists have shown CV benefits in patients with DM and CV disease in addition to a reduced risk of CKD progression.

Role of Inflammation in Progression of Chronic Kidney Disease in Type 2 Diabetes Mellitus: Clinical Implications

Progression of chronic kidney disease in type 2 diabetes has been understood conventionally as a consequence of intraglomerular hemodynamic changes and aberrant metabolic pathways. However, an increasing body of experimental evidence has highlighted the role of inflammatory response in the progression of diabetic kidney disease. Macrophage polarization in response to specific microenvironmental stimuli affects the pathology of diabetic kidneys. The diabetic milieu also up-regulates inflammatory cytokines, chemokines, and adhesion molecules, and promotes inflammatory signal transduction pathways, including inflammasomes. Therefore, from a reverse translational perspective, modulation of the inflammatory response may be the driving force of the renoprotective effects of renin-angiotensin system inhibitors, sodium-glucose cotransporter-2 inhibitors, and mineralocorticoid receptor antagonists, all of which have been shown to slow disease progression. Currently, many agents that target the inflammation in the kidneys directly are evaluated in clinical trials. This article discusses recent clinical and experimental milestones in drug development for diabetic kidney disease with a perspective on inflammation in the kidneys. Such insights may enable a targeted approach to discovering novel drugs against chronic kidney disease in type 2 diabetes.

RhoA/ROCK inhibition attenuates endothelin-1-induced elevated glomerular permeability to albumin, inflammation, and fibrosis

Endothelin-1 (ET-1) contributes to the development of kidney diseases. However, the underlying molecular mechanism is largely undefined. Here we sought to investigate the potential role of ET-1 receptors, ET_A and ET_B in the regulation of increased glomerular permeability and underlying signaling pathways post-ET-1 infusion. Male Sprague-Dawley rats were infused with ET-1 (2 pmol/kg per minute, i.v.) for four weeks, and the effect on glomerular permeability to albumin (P_alb) and albuminuria was measured. The selective ROCK-1/2 inhibitor, Y-27632, was administered to a separate group of rats to determine its effect on ET-1-induced P_alb and albuminuria. The role of ET_A and ET_B receptors in regulating RhoA/ROCK activity was determined by incubating isolated glomeruli from normal rats with ET-1 and with selective ET_A and ET_B receptor antagonists. ET-1 infusion for four weeks significantly elevated P_alb and albuminuria. Y-27632 significantly reduced the elevation of P_alb and albuminuria. The activities of both RhoA and ROCK-1/2 were increased by ET-1 infusion. Selective ET_B receptor antagonism had no effect on the elevated activity of both RhoA and ROCK-1/2 enzymes. Selective ET_A receptor and combined ET_A/ET_B receptors blockade restored the activity of RhoA and ROCK-1/2 to normal levels. In addition, chronic ET-1 infusion increased the levels of glomerular inflammatory and fibrotic markers. These effects were all attenuated in rats following ROCK-1/2 inhibition. These observations suggest that ET-1 contributes to increased albuminuria, inflammation, and fibrosis by modulating the activity of the ET_A-RhoA/ROCK-1/2 pathway. Selective ET_A receptor blockade may represent a potential therapeutic strategy to limit glomerular injury and albuminuria in kidney disease.

New Dual Endothelin Receptor Antagonist Aprocitentan in Hypertension: A Systematic Review and Meta-Analysis

Hypertension is one of the most common disorders encountered, yet pharmacotherapy for resistant hypertension has limited effective options. Aprocitentan is postulated to be a novel anti-hypertensive. The main goal was to determine the effect of aprocitentan on blood pressure among patients with hypertension. A thorough search of five electronic databases, including PubMed Central, PubMed, EMBASE, Springer, and Google Scholar, was carried out. The study included nine articles with a total of 2024 participants. With doses exceeding 25 mg, plasma ET-1(endothelin-1) concentrations, which show ETB (Endothelin receptor type B) receptor antagonism, significantly rose. Aprocitentan significantly reduced systolic and diastolic blood pressure with both doses of 10mg and 25mg in patients with hypertension. Further research is warranted to evaluate the efficacy, safety, and long-term outcomes of aprocitentan and its synergistic effect with other anti-hypertensives.

Clinical trials with reno-vascular end points in patients with diabetes: Changing the scenario over the past 20 years

Major clinical advances over the last 20 years in the area of diabetic kidney disease (DKD) have been confirmed in large seminal clinical trials. These findings add to the previously identified benefits resulting from intensive glucose and blood pressure control therapies. Furthermore, newer glucose lowering treatments such as SGLT2 inhibitors and GLP-1 agonists appear very promising and are likely to transform the management and outlook of DKD over the next decade. In addition, novel mineralocorticoid receptor antagonists and a recently reported trial with an endothelin receptor blocker also have the potential to change clinical practice.

Diabetic nephropathy: Focusing on pathological signals, clinical treatment, and dietary regulation

Diabetic nephropathy (DN) is one of the most severe complications of diabetes. However, due to its complex pathological mechanisms, no effective therapeutic methods (other than ACEIs and ARBs) have been applied, which have been used for many years in clinical practice. Recent studies have shown that emerging therapeutics, including novel target-based pharmacotherapy, cell therapies, and dietary regulation, are leading to new hopes for DN management. This review aims to shed new light on the treatment of DN by describing the important pathological mechanisms of DN and by analysing recent advances in clinical treatment, including drug therapy, cell therapy, and dietary regulation. In pathological mechanisms, RAAS activation, AGE accumulation, and EMT are involved in inflammation, cellular stress, apoptosis, pyroptosis, and autophagy. In pharmacotherapy, several new therapeutics, including SGLT2 inhibitors, GLP-1 agonists, and MRAs, are receiving public attention. In addition, stem cell therapies and dietary regulation are also being emphasized. Herein, we highlight the importance of combining therapy and dietary regulation in the treatment of DN and anticipate more basic research or clinical trials to verify novel strategies.

Endothelin Receptor Antagonists in Kidney Disease

Endothelin (ET) is found to be increased in kidney disease secondary to hyperglycaemia, hypertension, acidosis, and the presence of insulin or proinflammatory cytokines. In this context, ET, via the endothelin receptor type A (ET_A) activation, causes sustained vasoconstriction of the afferent arterioles that produces deleterious effects such as hyperfiltration, podocyte damage, proteinuria and, eventually, GFR decline. Therefore, endothelin receptor antagonists (ERAs) have been proposed as a therapeutic strategy to reduce proteinuria and slow the progression of kidney disease. Preclinical and clinical evidence has revealed that the administration of ERAs reduces kidney fibrosis, inflammation and proteinuria. Currently, the efficacy of many ERAs to treat kidney disease is being tested in randomized controlled trials; however, some of these, such as avosentan and atrasentan, were not commercialized due to the adverse events related to their use. Therefore, to take advantage of the protective properties of the ERAs, the use of ET_A receptor-specific antagonists and/or combining them with sodium-glucose cotransporter 2 inhibitors (SGLT2i) has been proposed to prevent oedemas, the main ERAs-related deleterious effect. The use of a dual angiotensin-II type 1/endothelin receptor blocker (sparsentan) is also being evaluated to treat kidney disease. Here, we reviewed the main ERAs developed and the preclinical and clinical evidence of their kidney-protective effects. Additionally, we provided an overview of new strategies that have been proposed to integrate ERAs in kidney disease treatment.

Endothelin receptor antagonists in kidney protection for diabetic kidney disease and beyond?

The burden of chronic kidney disease is increasing worldwide, largely due to the increasing global prevalence of diabetes mellitus and hypertension. While renin angiotensin system inhibitors and sodium-glucose cotransporter two inhibitors are the management cornerstone for reducing kidney and cardiovascular complications in patients with diabetic and non-diabetic kidney disease (DKD), they are partially effective and further treatments are needed to prevent the progression to kidney failure. Endothelin receptor antagonism represent a potential additional therapeutic option due to its beneficial effect on pathophysiological processes involved in progressive kidney disease including proteinuria, which are independently associated with progression of kidney disease. This review discusses the biological mechanisms of endothelin receptor antagonists (ERA) in kidney protection, the efficacy and safety of ERA in randomised controlled trials reporting on kidney outcomes, and its potential future use in both diabetic and non-DKDs.

Endothelin type A receptor blockade increases renoprotection in congestive heart failure combined with chronic kidney disease: Studies in 5/6 nephrectomized rats with aorto-caval fistula

BACKGROUND

Association of congestive heart failure (CHF) and chronic kidney disease (CKD) worsens the patient's prognosis and results in poor survival rate. The aim of this study was to examine if addition of endothelin type A (ET_A) receptor antagonist to the angiotensin-converting enzyme inhibitor (ACEi) will bring additional beneficial effects in experimental rats.

METHODS

CKD was induced by 5/6 renal mass reduction (5/6 NX) and CHF was elicited by volume overload achieved by creation of aorto-caval fistula (ACF). The follow-up was 24 weeks after the first intervention (5/6 NX). The treatment regimens were initiated 6 weeks after 5/6 NX and 2 weeks after ACF creation.

RESULTS

The final survival in untreated group was 15%. The treatment with ET_A receptor antagonist alone or ACEi alone and the combined treatment improved the survival rate to 64%, 71% and 75%, respectively, however, the difference between the combination and either single treatment regimen was not significant. The combined treatment exerted best renoprotection, causing additional reduction in albuminuria and reducing renal glomerular and tubulointerstitial injury as compared with ACE inhibition alone.

CONCLUSIONS

Our results show that treatment with ET_A receptor antagonist attenuates the CKD- and CHF-related mortality, and addition of ET_A receptor antagonist to the standard blockade of RAS by ACEi exhibits additional renoprotective actions.

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.

Advances in the Pharmacological Management of Diabetic Nephropathy: A 2022 International Update

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease (ESRD) worldwide. Its pathogenesis encompasses functional alterations involving elevated intraglomerular and systemic pressure, increased activity of the renin-angiotensin system (RAS) and oxidative stress, and the eventual development of renal fibrosis. The management of DN involves the optimization of blood pressure (BP) and blood glucose targets. However, treatment of these risk factors slows down but does not stop the progression of DN. Innovative pharmacologic therapies for dyslipidemia and type 2 diabetes mellitus (T2DM) could play a key role in bridging this gap and attenuating the residual risk of DN beyond traditional risk factor management. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), sodium-glucose cotransporter-2 inhibitors (SGLT-2is), and inhibitors of mineralocorticoid receptor-mediated sodium reabsorption are recently introduced drug classes that have been shown to have positive effects on kidney function in individuals with T2DM. The aim of this review is to provide an update on the therapeutic options available in order to prevent or slow the onset and progression of DN in diabetic patients.

The membrane-associated protein 17 (MAP17) is up-regulated in response to empagliflozin on top of RAS blockade in experimental diabetic nephropathy

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have proven to delay diabetic kidney disease (DKD) progression on top of the standard of care with the renin-angiotensin system (RAS) blockade. The molecular mechanisms underlying the synergistic effect of SGLT2i and RAS blockers is poorly understood. We gave a SGLT2i (empagliflozin), an angiotensin-converting enzyme inhibitor (ramipril), or a combination of both drugs for 8 weeks to diabetic (db/db) mice. Vehicle-treated db/db and db/m mice were used as controls. At the end of the experiment, mice were killed, and the kidneys were saved to perform a differential high-throughput proteomic analysis by mass spectrometry using isobaric tandem mass tags (TMT labeling) that allow relative quantification of the identified proteins. The differential proteomic analysis revealed 203 proteins differentially expressed in one or more experimental groups (false discovery rate < 0.05 and Log2 fold change ≥ ±1). Fourteen were differentially expressed in the kidneys from the db/db mice treated with empagliflozin with ramipril. Among them, MAP17 was up-regulated. These findings were subsequently validated by Western blot. The combined therapy of empagliflozin and ramipril up-regulated MAP17 in the kidney of a diabetic mice model. MAP17 is a major scaffolding protein of the proximal tubular cells that places transporters together, namely SGLT2 and NHE3. Our results suggest that SGLT2i on top of RAS blockade may protect the kidney by boosting the inactivation of NHE3 via the up-regulation of key scaffolder proteins such as MAP17.

Endothelin type A receptor blockade attenuates aorto-caval fistula-induced heart failure in rats with angiotensin II-dependent hypertension

OBJECTIVE

Evaluation of the effect of endothelin type A (ET A ) receptor blockade on the course of volume-overload heart failure in rats with angiotensin II-dependent hypertension.

METHODS

Ren-2 renin transgenic rats (TGR) were used as a model of hypertension. Heart failure was induced by creating an aorto-caval fistula (ACF). Selective ET A receptor blockade was achieved by atrasentan. For comparison, other rat groups received trandolapril, an angiotensin-converting enzyme inhibitor (ACEi). Animals first underwent ACF creation and 2 weeks later the treatment with atrasentan or trandolapril, alone or combined, was applied; the follow-up period was 20 weeks.

RESULTS

Eighteen days after creating ACF, untreated TGR began to die, and none was alive by day 79. Both atrasentan and trandolapril treatment improved the survival rate, ultimately to 56% (18 of 31 animals) and 69% (22 of 32 animals), respectively. Combined ACEi and ET A receptor blockade improved the final survival rate to 52% (17 of 33 animals). The effects of the three treatment regimens on the survival rate did not significantly differ. All three treatment regimens suppressed the development of cardiac hypertrophy and lung congestion, decreased left ventricle (LV) end-diastolic volume and LV end-diastolic pressure, and improved LV systolic contractility in ACF TGR as compared with their untreated counterparts.

CONCLUSION

The treatment with ET A receptor antagonist delays the onset of decompensation of volume-overload heart failure and improves the survival rate in hypertensive TGR with ACF-induced heart failure. However, the addition of ET A receptor blockade did not enhance the beneficial effects beyond those obtained with standard treatment with ACEi alone.

Expectations in children with glomerular diseases from SGLT2 inhibitors

Chronic kidney disease (CKD) is a global public healthcare concern in the pediatric population, where glomerulopathies represent the second most common cause. Although classification and diagnosis of glomerulopathies still rely mostly on histopathological patterns, patient stratification should complement information supplied by kidney biopsy with clinical data and etiological criteria. Genetic determinants of glomerular injury are particularly relevant in children, with important implications for prognosis and treatment. Targeted therapies addressing the primary cause of the disease are available for a limited number of glomerular diseases. Consequently, in the majority of cases, the treatment of glomerulopathies is actually the treatment of CKD. The efficacy of the currently available strategies is limited, but new prospects evolve. Although the exact mechanisms of action are still under investigation, accumulating data in adults demonstrate the efficacy of sodium-glucose transporter 2 inhibitors (SGLT2i) in slowing the progression of CKD due to diabetic and non-diabetic kidney disease. SGLT2i has proved effective on other comorbidities, such as obesity, glycemic control, and cardiovascular risk that frequently accompany CKD. The use of SGLT2i is not yet approved in children. However, no pathophysiological clues theoretically exclude their application. The hallmark of pediatric CKD is the inevitable imbalance between the metabolic needs of a growing child and the functional capacity of a failing kidney to handle those needs. In this view, developing better strategies to address any modifiable progressor in kidney disease is mandatory, especially considering the long lifespan typical of the pediatric population. By improving the hemodynamic adaptation of the kidney and providing additional beneficial effects on the overall complications of CKD, SGLT2i is a candidate as a potentially innovative drug for the treatment of CKD and glomerular diseases in children.

Emerging drugs for the treatment of diabetic nephropathy

INTRODUCTION

Diabetic nephropathy remains a significant economic and social burden on both the individual patient and health-care systems as the prevalence of diabetes increases in the general population. The complex pathophysiology of diabetic kidney disease poses a challenge in the development of effective medical treatments for the disease. However, the multiple facets of diabetic nephropathy also offer a variety of potential strategies to manage this condition.

AREAS COVERED

We retrieved PubMed, Cochrane Library, Scopus, Google Scholar, and ClinicalTrials.gov records to identify studies and articles focused on new pharmacologic advances to treat diabetic nephropathy.

EXPERT OPINION

RAAS blockers have remained the mainstay of therapy for DM nephropathy for many years, with only recent advancements with SGLT2 inhibitors and nonsteroidal MRAs. Better understanding of the long-term renal effects of ambient hyperglycemia, ranging from hemodynamic changes to increased production of oxidative and pro-inflammatory substances, has evolved our approach to the treatment of diabetic nephropathy. With continuing research for new therapeutics as well as combination therapy, the medical community may be able to better ease the burden of diabetic kidney disease.

Advances in the management of diabetic kidney disease: beyond sodium-glucose co-transporter 2 inhibitors

Progress in the treatment of diabetic kidney disease (DKD) has been modest since the early trials on renin-angiotensin-aldosterone system inhibitors (RAASis). Although sodium-glucose co-transporter 2 inhibitors (SGLT2is) have revolutionized the management of DKD by lowering proteinuria and protecting organs, other novel treatment approaches with good evidence and efficacy that can be used in conjunction with a RAASi or SGLT2i in managing DKD have emerged in the past few years. This review discusses the evidence for glucagon-like peptide-1 receptor agonist, selective mineralocorticoid receptor antagonist, and selective endothelin A receptor antagonist, emerging treatment options for DKD beyond SGLT2 inhibition.

Organic Anion Transporter Gene Variants Associated With Plasma Exposure and Long-Term Response to Atrasentan in Patients With Diabetic Kidney Disease

Plasma exposure of the endothelin receptor antagonist atrasentan varies between individuals and is associated with nephroprotective effects and the risk of heart failure. We examined the influence of genetic polymorphisms on atrasentan plasma exposure and pharmacodynamic effects. We performed a substudy of the Study of Diabetic Nephropathy With Atrasentan (SONAR) trial which enrolled adults with type 2 diabetes and chronic kidney disease (estimated glomerular filtration rate: 25-75 mL/min/1.73 m² , and a urine albumin-to-creatinine ratio of 300-5,000 mg/g). Single nucleotide polymorphisms (SNPs) were determined for prespecified membrane transporters, metabolizing enzymes, and the endothelin-1 peptide. The associations among genotype, atrasentan plasma exposure, and the effect of atrasentan on the prespecified kidney and heart failure hospitalization (HHF) outcomes was assessed with Cox proportional hazards regression models. Of 3,668 patients randomized, 2,329 (63.5%) consented to genotype analysis. Two SNPs in the SLCO1B1 gene (rs4149056 and rs2306283), encoding the hepatic organic anion transporter 1B1 (OATP1B1), showed the strongest association with atrasentan plasma exposure. Based on their SLCO1B1 genotype, patients were classified into normal (atrasentan area under the plasma-concentration time curve from zero to infinity (AUC_0-inf ) 41.3 ng·h/mL) or slow (atrasentan AUC_0-inf 49.7 ng·h/mL, P < 0.001) OATP1B1 transporter phenotypes. Among patients with a normal OATP1B1 phenotype, the hazard ratio (HR) with atrasentan for the primary kidney and HHF outcomes were 0.61 (95% confidence interval (CI): 0.45-0.81) and 1.35 (95% CI: 0.84-2.13), respectively. In the slow transporter phenotype, HRs for kidney and HHF outcomes were 1.95 (95% CI: 0.95-4.03, P-interaction normal phenotype = 0.004), and 4.18 (95% CI: 1.37-12.7, P-interaction normal phenotype = 0.060), respectively. OATP1B1 gene polymorphisms are associated with significant between-patient variability in atrasentan plasma exposure and long-term efficacy and safety.

Novel antihypertensive agents for resistant hypertension: what does the future hold?

Finding complementary compelling novel therapeutic agents for better control of blood pressure in people with resistant hypertension is moving into unchartered territory. The latest therapeutic developments explore approaches in the clinical arena that were either not examined or could only be examined in animal models two decades ago. Four main mechanisms have now been explored and operationalized in drug development: (a) mineralocorticoid receptor blockade using a nonsteroidal structure with many fewer side effects, (b) an aminopeptidase A inhibitor that has central effects on vasopressin, (c) a combined endothelin A and B receptor blocker and (d) an aldosterone synthase inhibitor devoid of glucocorticoid activity. All these agents are either completing Phase II development and starting Phase III or are involved in the ongoing recruitment of Phase III trials. Additionally, novel agents use antisense inhibition to block angiotensinogen development in the liver. These agents are discussed only for completeness, as they are still in Phase II trial development. Last, another agent that was initially being developed as an antihypertensive and once the data were reviewed by the company clearly showed efficacy as a heart failure agent was sacubitril/valsartan, which was ultimately approved. However, there are some discussions about reinvigorating the quest for an indication for hypertension, although no such steps have been formally initiated.

Recent Advances in the Emerging Therapeutic Strategies for Diabetic Kidney Diseases

Diabetic kidney disease (DKD) is one of the most common causes of end-stage renal disease worldwide. The treatment of DKD is strongly associated with clinical outcomes in patients with diabetes mellitus. Traditional therapeutic strategies focus on the control of major risk factors, such as blood glucose, blood lipids, and blood pressure. Renin–angiotensin–aldosterone system inhibitors have been the main therapeutic measures in the past, but the emergence of sodium–glucose cotransporter 2 inhibitors, incretin mimetics, and endothelin-1 receptor antagonists has provided more options for the management of DKD. Simultaneously, with advances in research on the pathogenesis of DKD, some new therapies targeting renal inflammation, fibrosis, and oxidative stress have gradually entered clinical application. In addition, some recently discovered therapeutic targets and signaling pathways, mainly in preclinical and early clinical trial stages, are expected to provide benefits for patients with DKD in the future. This review summarizes the traditional treatments and emerging management options for DKD, demonstrating recent advances in the therapeutic strategies for DKD.

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.

Hypertension mediated kidney and cardiovascular damage and risk stratification: Redefining concepts

Hypertension mediated organ damage (HMOD) refers to structural or functional changes in arteries or target organs that can be present in long-standing hypertension, but it can be also found in naïve never treated patients. Traditionally, cardiovascular risk is stratified with charts or calculators that tend to underestimate the real cardiovascular risk. The diagnosis of HMOD automatically reclassifies patients to the highest level of cardiovascular risk. Subclinical HMOD can be present already at the diagnosis of hypertension and more than 25% of hypertensives are misclassified with the routine tests recommended by hypertension guidelines. Whether HMOD regression improves cardiovascular outcomes has never been investigated in randomized clinical trials and remains controversial. However, different drugs have been probed with promising results in high cardiovascular risk patients, such as the new antidiabetic or the novel non-steroid mineralocorticoid antagonists. Accordingly, trials have shown that lowering blood pressure reduces cardiovascular events. In this narrative review, we will discuss the role of HMOD in cardiovascular risk stratification, the different types of organ damage, and the evidence available to define whether HMOD can be used as a therapeutic target.