Novel agents for treating IgA nephropathy

Recent status and trends of innate immunity and the gut-kidney aixs in IgAN: A systematic review and bibliometric analysis

BACKGROUND

There is a significant global demand for precise diagnosis and effective treatment of IgA nephropathy (IgAN), with innate immunity, particularly the complement system, exerting a profound influence on its pathogenesis. Additionally, the gut-kidney axis pathway is vital in the emergence and development of IgAN.

METHODS

We conducted a comprehensive search in the Web of Science database, spanning from January 1, 2000 to December 18, 2023. The gathered literature underwent a visual examination through CiteSpace, VOSviewer, and Scimago Graphica to delve into authors, nations, organizations, key terms, and other pertinent elements.

RESULT

Between 2000 and 2023, a total of 720 publications were identified, out of which 436 publications underwent screening for highly relevant literature analysis. The average annual number of articles focusing on IgAN, innate immunity, and the gut-kidney axis is approximately 31, with an upward trend observed. In terms of research impact encompassing publication count and authorship, the United States emerged as the leading contributor. Prominent keywords included "complement", "activation", "microbe", "gut-kidney axis", "C4d deposition", "alternative pathway" and "B cells" along with other prospective hot topics.

CONCLUSION

The correlation between IgAN and innate immunity is a focal point in current scientific research. Recent literature underscores the significance of the gut-kidney axis, where intestinal microorganisms and metabolites may influence IgAN. The complement system, a key component of innate immunity, also has a crucial function.Advancements in prevention, diagnosis, and treatment hinge on unraveling this intricate relationship.

Long-term renal survival in patients with IgA nephropathy: a systematic review

The management strategy for IgA nephropathy (IgAN), has undergone constant improvements since the disease entity was first described 50 years ago. However, it is still unknown how these changes affected the long-term renal survival of IgAN patients. We systematically evaluate changes in IgAN renal survival by searching PubMed, Embase, and the Cochrane Library Database of Systematic Reviews from inception to 19 May 2024. We included a large sample of 103076 IgAN cases from 158 studies. Renal survival rates were 94.16% (95% CI: 94.02% to 94.31%), 88.68% (95% CI: 88.48% to 88.87%), and 78.13% (95% CI: 77.82% to 78.43%) at three, five, and ten-year, respectively. Over the past few decades, there haven't been any sound changes in the 3-year and 5-year renal survival rates. The kidney survival rate in developed countries is higher than in developing countries. Researchers consistently show that while proteinuria < 1.0 g/24 h, renal survival rates increase dramatically. In IgAN, long-term renal survival fluctuated rather than continuously improving over time. Our system review's findings indicate that supportive care-the most important recommendation for managing IgAN has shown promising results. The long-term outcomes of IgAN could be significantly improved by the latest developed treatment options.

Emerging perspectives in the management of IgA nephropathy: a comprehensive review

IgA nephropathy (IgAN) is the most prevalent form of primary glomerulonephritis worldwide and a leading cause of chronic kidney disease and renal failure. This disorder is characterized by the deposition of immune complexes containing galactose-deficient forms of IgA and complement C3 in the glomeruli. Until now, disease management relied mainly on optimized supportive care. Systemic corticosteroid therapy is proposed for patients at high risk of disease progression, but the effectiveness and safety of this approach are under debate. A significant proportion of patients do not respond to current therapies and require kidney replacement therapy at a young age, with substantial costs and impact on quality of life. Recently, there have been multiple joint efforts to improve the understanding of IgAN pathophysiology. International collaborations resulted in multiple ongoing clinical trials that are providing new insights toward innovative therapeutic options such as SGLT2 inhibitors, dual endothelin and angiotensin receptor blockers, targeted-release budesonide, B-cell proliferation and differentiation inhibitors, and complement system blockers. Based on this new evidence, revision of the guidelines to manage IgAN is expected to occur in the near future. In addition to the novelty in therapeutic agents, there is also a growing interest in new noninvasive biomarkers for IgAN screening, risk stratification to monitor the course of the disease, and the response to treatment. In this review, we discuss current knowledge on the pathophysiology of IgAN, disease management, and emerging advances in clinical translation of IgAN research.

Renal Health Through Medicine-Food Homology: A Comprehensive Review of Botanical Micronutrients and Their Mechanisms

BACKGROUND

As an ancient concept and practice, "food as medicine" or "medicine-food homology" is receiving more and more attention these days. It is a tradition in many regions to intake medicinal herbal food for potential health benefits to various organs and systems including the kidney. Kidney diseases usually lack targeted therapy and face irreversible loss of function, leading to dialysis dependence. As the most important organ for endogenous metabolite and exogenous nutrient excretion, the status of the kidney could be closely related to daily diet. Therefore, medicinal herbal food rich in antioxidative, anti-inflammation micronutrients are ideal supplements for kidney protection. Recent studies have also discovered its impact on the "gut-kidney" axis.

METHODS

Here, we review and highlight the kidney-protective effects of botanicals with medicine-food homology including the most frequently used Astragalus membranaceus and Angelica sinensis (Oliv.) Diels, concerning their micronutrients and mechanism, offering a basis and perspective for utilizing and exploring the key substances in medicinal herbal food to protect the kidney.

RESULTS

The index for medicine-food homology in China contains mostly botanicals while many of them are also consumed by people in other regions. Micronutrients including flavonoids, polysaccharides and others present powerful activities towards renal diseases.

CONCLUSIONS

Botanicals with medicine-food homology are widely speeded over multiple regions and incorporating these natural compounds into dietary habits or as supplements shows promising future for renal health.

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.

Deciphering roles of protein post-translational modifications in IgA nephropathy progression and potential therapy

Immunoglobulin A nephropathy (IgAN), one type of glomerulonephritis, displays the accumulation of glycosylated IgA in the mesangium. Studies have demonstrated that both genetics and epigenetics play a pivotal role in the occurrence and progression of IgAN. Post-translational modification (PTM) has been revealed to critically participate in IgAN development and progression because PTM dysregulation results in impaired degradation of proteins that regulate IgAN pathogenesis. A growing number of studies identify that PTMs, including sialylation, o-glycosylation, galactosylation, phosphorylation, ubiquitination and deubiquitination, modulate the initiation and progression of IgAN. Hence, in this review, we discuss the functions and mechanisms of PTMs in regulation of IgAN. Moreover, we outline numerous compounds that govern PTMs and attenuate IgAN progression. Targeting PTMs might be a useful strategy to ameliorate IgAN.

Treatment of Patients with IgA Nephropathy: Evaluation of the Safety and Efficacy of Mycophenolate Mofetil

INTRODUCTION AND AIM

Immunoglobulin A nephropathy (IgAN), characterized by aberrant IgA immune complex deposition, is the most prevalent primary glomerular disease and the main cause of end-stage renal disease, causing a significant physical and psychological burden on people worldwide. Conventional therapeutic approaches, such as renin-angiotensin-aldosterone system inhibitors and corticosteroids, may not achieve sufficient effectiveness and may produce major side events in the past. The previous data in Asian populations indicated that mycophenolate mofetil (MMF) might significantly advance the development of a new therapy strategy for IgAN. The effectiveness and safety of MMF in patients with IgAN will be investigated in this study.

METHODS

A literature search was conducted on June 30th, 2023, by searching the following databases: PubMed and the Cochrane Library according to predefined criteria. To investigate the renoprotective benefits and safety of MMF, statistical analyses were performed using Cochrane's Review Manager Version 5.3.

RESULTS

The meta-analysis included nine randomized controlled studies that fulfilled the inclusion criterion. In the Asian population, the results revealed a substantial difference in remission rates between the MMF group and the control group (OR: 2.53, 95% CI: 1.02, 6.30, P = 0.05). MMF can increase the rate of decrease in proteinuria in IgAN patients when compared with controls in Asians (OR: 7.34, 95% CI: 2.69, 20.08, P = 0.0001), and MMF can reduce the urinary protein in patients with IgAN in Asians (WMD: -0.61, 95% CI: -1.15, -0.08, P = 0.02). Interestingly, these studies on Asians were conducted in China. However, the differences in remission rate, rate of decrease in proteinuria, and urinary protein reduction between the MMF group and control group were not found in overall populations and in the Caucasian population. The differences in complete remission rate, partial remission rate, serum creatinine (SCr) doubling rate, rate of 50% increase in SCr, and rate of need for renal replacement treatment between the MMF group and control group were not found in Asians, Caucasians, and overall populations. The difference in the rate of side effects between the MMF group and the control group was not found.

CONCLUSION

MMF protects renal function and is a safe medication for treating Chinese IgAN patients. MMF might significantly advance the development of a new therapy strategy for IgAN in the Chinese population.

Clinical Practice Patterns in IgA Nephropathy: A Global Questionnaire-Based Survey

Introduction

IgA nephropathy (IgAN) displays ethnic differences in disease phenotype. We aimed to examine how this common disease is managed worldwide.

Methods

An online 2-step questionnaire-based survey was conducted among nephrologists globally focusing on various management strategies used in IgAN.

Results

A total of 422 nephrologists responded to the initial survey and 339 to the follow-up survey. Of the nephrologists, 13.7% do not get MEST-C scores in biopsy reports; 97.2% of nephrologists use renin-angiotensin-aldosterone system (RAAS) blockade with angiotensin-converting-enzyme inhibitors (ACEi) / angiotensin receptor blockers (ARB) as initial treatment. Other supportive treatments commonly employed are fish oil (43.6%) and sodium-glucose co-transporter-2 (SGLT2) inhibitors (48.6%) with regional differences. Immunosuppression is generally (92.4%) initiated when proteinuria >1 g/d persists for ≥3 months.Main considerations for initiating immunosuppression are level of proteinuria (87.9%), estimated glomerular filtration rate (eGFR) decline (78.7%), lack of response to RAAS blockade (57.6%) and MEST-C score (64.9%). Corticosteroids (89.1%) are universally used as first-line immunosuppression; mycophenolate mofetil is commonly used in resistant patients (49.3%). Only 30.4% nephrologist enroll patients with persistent proteinuria >1 g/d in clinical trials. Nephrologists in Europe (63.6%), North America (56.5%), and Australia (63.6%) are more likely to do so compared to South America (31.3%) and Asia (17.2%). Only 8.1% nephrologists in lower-middle income countries (LMICs) enroll patients in clinical trials, though 40% of them are aware of such trials in their nations.

Conclusion

Although most nephrologists agree on common parameters to assess clinical severity of IgAN, use of RAAS blockade, and blood pressure control, there is heterogeneity in use of other supportive therapies and initiation of immunosuppression. There is reluctance to enroll patients in clinical trials with novel treatments, principally in LMICs.