Clinical trials in minimal change disease

Detailed Pathophysiology of Minimal Change Disease: Insights into Podocyte Dysfunction, Immune Dysregulation, and Genetic Susceptibility

Minimal Change Disease (MCD) is a predominant cause of idiopathic nephrotic syndrome in the pediatric population, yet presents significant clinical challenges due to its frequent relapses and steroid resistance. Despite its relatively benign histological appearance, MCD is characterized by severe proteinuria, hypoalbuminemia, and edema, which may affect patient outcomes. Current treatment strategies primarily rely on corticosteroids, which are effective in inducing remission but are associated with high relapse rates, steroid resistance, and numerous long-term side effects, underscoring the need for more targeted and effective therapeutic approaches. This narrative review synthesizes current knowledge on the pathophysiological mechanisms underlying MCD, focusing on the following three critical areas: podocyte dysfunction, immune dysregulation, and genetic susceptibility. Podocyte dysfunction, particularly involving alterations in nephrin, plays a central role in the breakdown of the glomerular filtration barrier, leading to the characteristic proteinuria observed in MCD. Immune dysregulation, including the presence of autoantibodies against nephrin and other podocyte components, exacerbates podocyte injury and contributes to disease progression, suggesting an autoimmune component to the disease. Genetic factors, particularly mutations in the NPHS1 and NPHS2 genes, have been identified as significant contributors to disease susceptibility, influencing the variability in treatment response and overall disease severity. Understanding these mechanisms is crucial for developing targeted therapies that address the underlying causes of MCD rather than merely managing its symptoms. This review highlights the need for further research into these pathophysiological processes to pave the way for more personalized and effective treatment strategies, ultimately improving patient outcomes and reducing reliance on corticosteroids.

Ultra-low-dose rituximab is effective for the treatment of patients with minimal change disease - A retrospective study

BACKGROUND PURPOSE

Rituximab (RTX),an anti-CD20 monoclonal antibody can effectively treat minimal change disease (MCD),with low toxicity and a reduced steroid dosage. The optimal dosage of RTX for treating MCD remains unclear. This study aimed to investigate the efficacy of an ultra-low-dose regimen of RTX (100 mg per week for 4 weeks) for treating MCD.

METHODS

We retrospectively analyzed clinical data from 31 patients with MCD who received RTX. Seventeen patients received ultra-low-dose RTX (ULD-RTX) therapy, and 14 patients received standard-dose RTX (SD-RTX) therapy (500 mg weekly for 4 weeks). All patients were followed up for at least 6 months.

RESULTS

Both groups showed significant increases in the serum albumin levels and notable decreases in the urinary protein levels in the 1st and 6th months after RTX therapy. There were no significant differences in the plasma albumin or urinary protein levels between the groups (p > 0.05). B-cell depletion was observed in all patients after 1 month of RTX administration. At 6 months after RTX treatment, the remission rate was 93% in the SD-RTX group and 88% in the ULD-RTX group (p > 0.05). The ULD-RTX therapy incurred lower costs than did the SD-RTX therapy. One patient in the SD-RTX group developed community-acquired pneumonia.

CONCLUSION

Ultra-low-dose RTX is effective at inducing remission in patients with MCD at a lower cost.

Knowledge Translation in Glomerulonephritis: Successes in Translational Research From the Bench to Bedside

Purpose of review

Glomerulonephritis refers to a rare group of diseases characterized by glomerular inflammation, which collectively are a common cause of kidney failure. Until recently, there was a lack of high-quality clinical trials to inform the care of patients with glomerulonephritides. We identified examples of successful translational research spanning from basic science to clinical applications, and highlight gaps in implementation science.

Sources of information

The focus of our review was derived from discussions between health care professionals, researchers, and patient partners. We also performed literature searches pertaining to the treatment of glomerulonephritis in PubMed and Google Scholar.

Methods

Examples of successful knowledge translation were generated through review of new evidence in the past 5 years and by iterative discussions by the authors. We then conducted a narrative review of several themes related to knowledge translation in glomerulonephritis. This was complemented by an interview with a patient partner to provide an example of a patient's perspective living with glomerulonephritis.

Key findings

We summarized selected recent advances in glomerulonephritis and its knowledge translation in the following domains: (1) identification of auto-antibodies in membranous nephropathy and minimal change disease; (2) clinical trials of novel targeted therapies for IgA nephropathy and lupus nephritis, which have led to approval of new treatments; (3) developments in research networks and clinical trials in glomerulonephritis; (4) recognition of the importance in developing standardized patient reported outcome measures in clinical trials; and (5) barriers in knowledge translation including access to medication.

Limitations

A systematic search of the literature and formal assessment of quality of evidence were beyond the scope of this review.

N-acetylneuraminate pyruvate lyase controls sialylation of muscle glycoproteins essential for muscle regeneration and function

Deleterious variants in N-acetylneuraminate pyruvate lyase (NPL) cause skeletal myopathy and cardiac edema in humans and zebrafish, but its physiological role remains unknown. We report generation of mouse models of the disease: NplR63C, carrying the human p.Arg63Cys variant, and Npldel116 with a 116-bp exonic deletion. In both strains, NPL deficiency causes drastic increase in free sialic acid levels, reduction of skeletal muscle force and endurance, slower healing and smaller size of newly formed myofibers after cardiotoxin-induced muscle injury, increased glycolysis, partially impaired mitochondrial function, and aberrant sialylation of dystroglycan and mitochondrial LRP130 protein. NPL-catalyzed degradation of sialic acid in the muscle increases after fasting and injury and in human patient and mouse models with genetic muscle dystrophy, demonstrating that NPL is essential for muscle function and regeneration and serves as a general marker of muscle damage. Oral administration of N-acetylmannosamine rescues skeletal myopathy, as well as mitochondrial and structural abnormalities in NplR63C mice, suggesting a potential treatment for human patients.

Discovery of Autoantibodies Targeting Nephrin in Minimal Change Disease Supports a Novel Autoimmune Etiology

BACKGROUND

Failure of the glomerular filtration barrier, primarily by loss of slit diaphragm architecture, underlies nephrotic syndrome in minimal change disease. The etiology remains unknown. The efficacy of B cell-targeted therapies in some patients, together with the known proteinuric effect of anti-nephrin antibodies in rodent models, prompted us to hypothesize that nephrin autoantibodies may be present in patients with minimal change disease.

METHODS

We evaluated sera from patients with minimal change disease, enrolled in the Nephrotic Syndrome Study Network (NEPTUNE) cohort and from our own institutions, for circulating nephrin autoantibodies by indirect ELISA and by immunoprecipitation of full-length nephrin from human glomerular extract or a recombinant purified extracellular domain of human nephrin. We also evaluated renal biopsies from our institutions for podocyte-associated punctate IgG colocalizing with nephrin by immunofluorescence.

RESULTS

In two independent patient cohorts, we identified circulating nephrin autoantibodies during active disease that were significantly reduced or absent during treatment response in a subset of patients with minimal change disease. We correlated the presence of these autoantibodies with podocyte-associated punctate IgG in renal biopsies from our institutions. We also identified a patient with steroid-dependent childhood minimal change disease that progressed to end stage kidney disease; she developed a massive post-transplant recurrence of proteinuria that was associated with high pretransplant circulating nephrin autoantibodies.

CONCLUSIONS

Our discovery of nephrin autoantibodies in a subset of adults and children with minimal change disease aligns with published animal studies and provides further support for an autoimmune etiology. We propose a new molecular classification of nephrin autoantibody minimal change disease to serve as a framework for instigation of precision therapeutics for these patients.

CD80 Insights as Therapeutic Target in the Current and Future Treatment Options of Frequent-Relapse Minimal Change Disease

Minimal change disease (MCD) is the most common cause of idiopathic nephrotic syndrome in children, and it is well known for its multifactorial causes which are the manifestation of the disease. Proteinuria is an early consequence of podocyte injury and a typical sign of kidney disease. Steroid-sensitive patients react well with glucocorticoids, but there is a high chance of multiple relapses. CD80, also known as B7-1, is generally expressed on antigen-presenting cells (APCs) in steroid-sensitive MCD patients. Various glomerular disease models associated with proteinuria demonstrated that the detection of CD80 with the increase of urinary CD80 was strongly associated closely with frequent-relapse MCD patients. The role of CD80 in MCD became controversial because one contradicts finding. This review covers the treatment alternatives for MCD with the insight of CD80 as a potential therapeutic target. The promising effectiveness of CD20 (rituximab) antibody and CD80 inhibitor (abatacept) encourages further investigation of CD80 as a therapeutic target in frequent-relapse MCD patients. Therapeutic-based antibody towards CD80 (galiximab) had never been investigated in MCD or any kidney-related disease; hence, the role of CD80 is still undetermined. A new therapeutic approach towards MCD is essential to provide broader effective treatment options besides the general immunosuppressive agents with gruesome adverse effects.