Another case of focal segmental glomerulosclerosis in an acutely uraemic patient following interferon therapy

Colony stimulating factor-1 receptor drives glomerular parietal epithelial cell activation in focal segmental glomerulosclerosis

Parietal epithelial cells (PECs) are kidney progenitor cells with similarities to a bone marrow stem cell niche. In focal segmental glomerulosclerosis (FSGS) PECs become activated and contribute to extracellular matrix deposition. Colony stimulating factor-1 (CSF-1), a hematopoietic growth factor, acts via its specific receptor, CSF-1R, and has been implicated in several glomerular diseases, although its role on PEC activation is unknown. Here, we found that CSF-1R was upregulated in PECs and podocytes in biopsies from patients with FSGS. Through in vitro studies, PECs were found to constitutively express CSF-1R. Incubation with CSF-1 induced CSF-1R upregulation and significant transcriptional regulation of genes involved in pathways associated with PEC activation. Specifically, CSF-1/CSF-1R activated the ERK1/2 signaling pathway and upregulated CD44 in PECs, while both ERK and CSF-1R inhibitors reduced CD44 expression. Functional studies showed that CSF-1 induced PEC proliferation and migration, while reducing the differentiation of PECs into podocytes. These results were validated in the Adriamycin-induced FSGS experimental mouse model. Importantly, treatment with either the CSF-1R-specific inhibitor GW2580 or Ki20227 provided a robust therapeutic effect. Thus, we provide evidence of the role of the CSF-1/CSF-1R pathway in PEC activation in FSGS, paving the way for future clinical studies investigating the therapeutic effect of CSF-1R inhibitors on patients with FSGS.

Nephrotic-range proteinuria and membranoproliferative glomerulonephritis-like pattern caused by interferon-β1b in a patient with multiple sclerosis

Interferon-beta (IFN-β) subtypes are widely used as immunomodulatory agents for relapsing-remitting multiple sclerosis (MS). Although generally well tolerated, a growing number of reports have recently shown association of long-term IFN-β therapy with several types of glomerulonephritis. Here, we present the case of a 42-year-old woman with MS who developed nephrotic-range proteinuria after taking IFN-β1b for nine years. Initially, due to the presence of histological features consistent with immunoglobulin A (IgA) nephropathy (granular IgA deposits in mesangial lesions), a tonsillectomy plus steroid pulse therapy was performed. However, proteinuria did not significantly decrease after these treatments. Therefore, a second renal biopsy was performed after three years, revealing a membranoproliferative glomerulonephritis-like pattern without immune complex. Further immunofluorescence analysis showed attenuated IgA staining. Consequently, IFN-β1b was replaced with dimethyl fumarate, resulting in complete remission, with proteinuria decreasing to the level of 0.2 g/day. Although it is a rare adverse effect, physicians should pay careful attention to the symptoms and findings of nephritis during the follow-up of patients under treatment with this agent.

Renal diseases associated with multiple sclerosis: A narrative review

The mechanisms of renal pathology in multiple sclerosis (MS) can be related to the disease itself or its treatment. Although kidney disease can be associated with MS, not much has been reported in the literature; hence, our study aimed to describe the prevalence and types of renal diseases and discuss their prognosis in patients with MS. A literature search (2012-2022) was performed using the Scale for the Assessment of Narrative Review Articles. The databases searched included MEDLINE (PubMed) and EMBASE. Fourteen articles from these databases met the inclusion criteria. The inclusion criteria were as follows: publications with full-text access. Articles published in English. Original articles related to renal diseases in MS. The prevalence of renal diseases in MS from the articles obtained ranged from 0.74% to 2.49%. Interferon beta (IFN-β)-associated glomerulonephritis was common among the reviewed articles. Significant improvement and resolution of the pathology were observed after the discontinuation of the offending medication. Renal symptoms in 2 out of 4 cases with renal thrombotic microangiopathy (TMA) induced by interferon-beta progressed to chronic kidney disease, even after the drug was stopped. Other studied renal pathologies included nephrolithiasis secondary to urinary retention and urinary catheter use in patients with MS.

Nephrotic-range proteinuria on interferon-β treatment: immune-induced glomerulonephritis or other pathway?

We present a case report of a 37-year-old woman with multiple sclerosis (MS) who developed nephrotic-range proteinuria secondary to membrano proliferative glomerulonephritis (MPGN)-like disease with mesangial C3 deposition without evidence of immune-complex deposition in the context of long-term interferon-β (IFN-β) therapy. The complete remission of proteinuria following cessation of IFN-β, strongly suggests causality. To our knowledge, this is the second case report of MPGN associated with IFN-β use. This being the case, the negative immune screen, normal inflammatory markers and the absence of immune complex deposits would imply a different pathway to that previously suggested.

Treatment with IFN-{alpha}, -{beta}, or -{gamma} is associated with collapsing focal segmental glomerulosclerosis

BACKGROUND AND OBJECTIVES

Treatment with IFN is rarely associated with nephrotic syndrome and renal biopsy findings of minimal-change disease or FSGS.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We report 11 cases of collapsing FSGS that developed during treatment with IFN and improved after discontinuation of therapy.

RESULTS

The cohort consists of seven women and four men with a mean age of 48.2 yr. Ten of the 11 patients were black. Six patients were receiving IFN-alpha for hepatitis C virus infection (n = 5) or malignant melanoma (n = 1), three were receiving IFN-beta for multiple sclerosis, and two were treated with IFN-gamma for idiopathic pulmonary fibrosis. After a median and mean [corrected] duration of therapy of 4.0 and 12.6 months, respectively, patients presented with acute renal failure (mean creatinine 3.5 mg/dl) and nephrotic-range proteinuria (mean 24-hour urine protein 9.7 g). Renal biopsy revealed collapsing FSGS with extensive foot process effacement and many endothelial tubuloreticular inclusions. Follow-up was available for 10 patients, all of whom discontinued IFN. At a mean of 23.6 months, nine of 10 patients had improvement in renal function, including one with complete remission and two with partial remission. Among the seven patients with available data, mean proteinuria declined from 9.9 to 3.0 g/d. Four of the seven patients were treated with immunosuppression, and there was no detectable benefit.

CONCLUSIONS

Collapsing FSGS may occur after treatment with IFN-alpha, -beta, or -gamma and is typically accompanied by the ultrastructural finding of endothelial tubuloreticular inclusions. Optimal therapy includes discontinuation of IFN.

Antiviral Drug-Induced Nephrotoxicity

Drug-induced kidney injury is a major side effect in clinical practice, frequently leading to acute renal failure (ARF). It accounts for more than 2% to 15% of cases of ARF in patients admitted to the hospital or in the intensive care unit, respectively. The exact frequency of nephrotoxicity induced by antiviral drugs is difficult to determine. Antiviral drugs cause renal failure through a variety of mechanisms. Direct renal tubular toxicity has been described with a number of new medications with unique effects on epithelial cells of the kidney. These include cidofovir, adefovir dipivoxil, and tenofovir, as well as acyclovir. Additionally, crystal deposition in the kidney may promote the development of renal failure. Several different drugs have been described to induce crystal nephropathy, including acyclovir and the protease inhibitor indinavir. Renal injury associated with antiviral drugs involves diverse processes having effects on the renal transporters, as well as on tubule cells. In this article, we review the pathogenesis of antiviral drug-induced kidney injury, common nephrotoxic renal syndromes, and strategies for preventing kidney injury.