Comparison of the influence of angiotensin-converting enzyme inhibitor lisinopril and angiotensin II receptor antagonist losartan in patients with idiopathic membranous nephropathy and nephrotic syndrome

Nephrotic Syndrome and Renin-angiotensin System: Pathophysiological Role and Therapeutic Potential

Idiopathic Nephrotic Syndrome (INS) is the most frequent etiology of glomerulopathy in pediatric patients and one of the most common causes of chronic kidney disease (CKD) and end-stage renal disease (ESRD) in this population. In this review, we aimed to summarize evidence on the pathophysiological role and therapeutic potential of the Renin-Angiotensin System (RAS) molecules for the control of proteinuria and for delaying the onset of CKD in patients with INS. This is a narrative review in which the databases PubMed, Web of Science, and Sci- ELO were searched for articles about INS and RAS. We selected articles that evaluated the pathophysiological role of RAS and the effects of the alternative RAS axis as a potential therapy for INS. Several studies using rodent models of nephropathies showed that the treatment with activators of the Angiotensin-Converting Enzyme 2 (ACE2) and with Mas receptor agonists reduces proteinuria and improves kidney tissue damage. Another recent paper showed that the reduction of urinary ACE2 levels in children with INS correlates with proteinuria and higher concentrations of inflammatory cytokines, although data with pediatric patients are still limited. The molecules of the alternative RAS axis comprise a wide spectrum, not yet fully explored, of potential pharmacological targets for kidney diseases. The effects of ACE2 activators and receptor Mas agonists show promising results that can be useful for nephropathies including INS.

Case Report: A Rare Presentation of NSAID-Induced Secondary Membranous Nephropathy in a Pediatric Patient

Background: Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults, but it is responsible for <5% of nephrotic syndrome cases in children. MN has primary and secondary forms. Secondary MN is caused by viral infections, autoimmune diseases like lupus, or drugs. Non-steroid anti-inflammatory drug (NSAID)-induced secondary MN is rarely described in the pediatric population. Thus, the clinical presentation and time to recovery are vastly unknown in the pediatric subgroup. Clinical Presentation: We report a case of a 15-year-old female who presented with acute onset of nephrotic range proteinuria, significant hypoalbuminemia, hyperlipidemia, and lower extremity edema related to the presence of nephrotic syndrome. She had a history of ibuprofen use periodically for 6 months before presentation because of menstrual cramps and intermittent lower abdominal pain. After the presentation, we performed a renal biopsy that reported stage 1-2 MN, likely secondary. The phospholipase A2 receptor (PLA2R) antibody on the blood test and PLA2R immune stain on the renal biopsy sample were negative. We performed a comprehensive evaluation of the viral and immune causes of secondary MN, which was non-revealing. She had stopped ibuprofen use subsequent to the initial presentation. She was prescribed ACE inhibitor therapy. After 6 months of ACE inhibitor treatment, the proteinuria had resolved. Conclusion: Proteinuria can last for several weeks when NSAID induces secondary MN and nephrotic syndrome. With the widespread use of NSAIDs prevalent in the pediatric community, further studies are needed to evaluate and study the role of NSAIDs in this condition.

New Ways of Understanding Membranous Nephropathy

BACKGROUND

In the last decade, great advances have been made in the field of membranous nephropathy (MN). The autoimmune nature of the disease has been confirmed with the description of diverse antigens, and few but very important prospective trials regarding treatment alternatives have been published, changing profoundly the way we understand this entity. Nowadays, an individualized therapeutic scheme based on clinical and serologic data appears to be the most appropriate method to manage patients with MN. Although there is still a long way to go, it is expected that future scientific progress will enable a patient-centered medicine based on concept-driven therapies.

SUMMARY

MN is the most common cause of nephrotic syndrome (NS) in white adults. Approximately one-third of patients achieve spontaneous remission, one-third remain stable, and one-third have an aggressive course with persistent NS and deterioration of renal function. About 80% of patients have circulating autoantibodies to phospholipase A2 receptor 1. Numerous therapies have been described including alkylating agents, rituximab, and calcineurin inhibitors, but new drugs are currently being explored. Here, we review the most important aspects regarding MN with an emphasis on results of the most recent clinical trials and pathophysiologic advances. Key Messages: 1. Evolving pathophysiologic concepts and recently published clinical trials have deeply changed our view of MN. 2. Most patients with MN present autoantibodies against diverse glomerular antigens. 3. Currently, an individual patient-centered management based on clinical and serologic markers is the most adequate approach to treat patients with MN.

Comparative proteinuria management of different angiotensin-converting enzyme inhibitors or angiotensin receptor blockers for normotensive patients with CKD: a Bayesian network meta-analysis

Background

Both angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are blood pressure-lowering agents, but they are also being used to control proteinuria in early chronic kidney disease (CKD) patients. However, clinically, some patients present merely proteinuria without hypertension. No guidelines pointed out how to select treatments for proteinuria in normotensive patients. Thus, we conducted a Bayesian network analysis to evaluate the relative effects of different kinds of ACEI or ARB or their combination on proteinuria and blood pressure reduction.

Methods

The protocol was registered in PROSPERO with ID CRD42017073721. A comprehensive literature database query was carried out systematically according to PICOS strategies. The primary outcome was reduction in proteinuria, and the secondary outcomes were eGFR reduction and blood pressure reduction. Random-effects pairwise and Bayesian network meta-analyses were used to estimate the effect of different regimens.

Results

A total of 14 RCTs with 1,098 patients were included in the analysis. All treatment strategies of ACEI, ARB or their combination had significantly greater efficacy in reducing proteinuria than placebo in normotensive CKD patients. The combination therapy of olmesartan+temocapril had the highest probability (22%) of being the most effective treatment to reduce proteinuria in normotensive CKD patients. Olmesartan and lisinopril ranked second (12%), and temocapril ranked third (15%) but reduced blood pressure less than placebo. For IgA nephropathy, the combination therapy of olmesartan+temocapril also had the highest probability (43%) of being the best antiproteinuric treatment, while enalapril had the highest probability (58%) of being the best antiproteinuric therapy for diabetic nephropathy.

Conclusions

The combination therapy of olmesartan plus temocapril appeared to be the most efficacious for reducing proteinuria in normotensive CKD patients and IgA nephropathy, but the clinical application should be balanced against potential harms. Temocapril can be an option when practitioners are searching for more proteinuria reduction but less blood pressure variation. In normotensive diabetic nephropathy, monotherapy with the ACEI enalapril seems to be the most efficacious intervention for reducing albuminuria. Future studies are required to give a more definitive recommendation.

Treatment of membranous nephropathy: time for a paradigm shift

In patients with membranous nephropathy, alkylating agents (cyclophosphamide or chlorambucil) alone or in combination with steroids achieve remission of nephrotic syndrome more effectively than conservative treatment or steroids alone, but can cause myelotoxicity, infections, and cancer. Calcineurin inhibitors can improve proteinuria, but are nephrotoxic. Most patients relapse after treatment withdrawal and can become treatment dependent, which increases the risk of nephrotoxicity. The discovery of nephritogenic autoantibodies against podocyte M-type phospholipase A2 receptor (PLA₂R) and thrombospondin type-1 domain- containing protein 7A (THSD7A) antigens provides a clear pathophysiological rationale for interventions that specifically target B-cell lineages to prevent antibody production and subepithelial deposition. The anti-CD20 monoclonal antibody rituximab is safe and achieves remission of proteinuria in approximately two-thirds of patients with membranous nephropathy. In those with PLA₂R-related disease, remission can be predicted by anti-PLA₂R antibody depletion and relapse by antibody re-emergence into the circulation. Thus, integrated evaluation of serology and proteinuria could guide identification of affected patients and treatment with individually tailored protocols. Nonspecific and toxic immunosuppressive regimens will fall out of use. B-cell modulation by rituximab and second-generation anti-CD20 antibodies (or plasma cell-targeted therapy in anti-CD20 resistant forms of disease) will lead to a novel therapeutic paradigm for patients with membranous nephropathy.

Nox and renal disease

Since the first demonstration of Nox enzyme expression in the kidney in the early 1990s and the subsequent identification of Nox4, or RENOX, a decade later, it has become apparent that the Nox family of reactive oxygen species (ROS) generating enzymes plays an integral role in the normal physiological function of the kidney. As our knowledge of Nox expression patterns and functions in various structures and specialized cell types within the kidney grows, so does the realization that Nox-derived oxidative stress contributes significantly to a wide variety of renal pathologies through their ability to modify lipids and proteins, damage DNA and activate transcriptional programmes. Diverse studies demonstrate key roles for Nox-derived ROS in kidney fibrosis, particularly in settings of chronic renal disease such as diabetic nephropathy. As the most abundant Nox family member in the kidney, much emphasis has been placed on the role of Nox4 in this setting. However, an ever growing body of work continues to uncover key roles for other Nox family members, not only in diabetic kidney disease, but in a diverse array of renal pathological conditions. The objective of the present review is to highlight the latest novel developments in renal Nox biology with an emphasis not only on diabetic nephropathy but many of the other renal disease contexts where oxidative stress is implicated.