Background: The glomerular endothelial glycocalyx is degraded during inflammation. The glycocalyx plays a pivotal role in endothelial function and is involved in many processes including binding of... Show moreBackground: The glomerular endothelial glycocalyx is degraded during inflammation. The glycocalyx plays a pivotal role in endothelial function and is involved in many processes including binding of chemokines and cytokines, leukocyte trafficking, and preventing proteinuria. HS-based therapeutics are a promising novel class of anti-inflammatory drugs to restore a compromised endothelial glycocalyx under inflammatory conditions. Recently, we demonstrated that treatment with HS extracted from unstimulated glomerular endothelial glycocalyx (unstimulated HSglx) reduced albuminuria during anti-GBM induced glomerulonephritis. Since endothelial HS domains are distinct in unstimulated versus inflammatory conditions, we hypothesized that 1) unstimulated HSglx, 2) LPS-stimulated HSglx, 3) the HS-mimetic fucoidan and 4) the glycosaminoglycan preparation sulodexide, which is a mixture of low molecular weight heparin and dermatan sulfate, might have different beneficial effects in experimental glomerulonephritis.Methods: The effect of unstimulated HSglx, LPS HSglx, Laminaria japonica fucoidan, or sulodexide on experimental glomerulonephritis was tested in LPS-induced glomerulonephritis in mice. Analyses included urinary albumin creatinine measurement, cytokine expression in plasma and renal cortex, and renal influx of immune cells determined by flow cytometry and immunofluorescence staining. Furthermore, the observed in vivo effects were evaluated in cultured glomerular endothelial cells and peripheral blood mononuclear cells by measuring cytokine and ICAM-1 expression levels. The ability of the compounds to inhibit heparanase activity was assessed in a heparanase activity assay.Results: Treatment of mice with LPS HSglx or sulodexide near-significantly attenuated LPS-induced proteinuria. All treatments reduced plasma MCP-1 levels, whereas only fucoidan reduced IL-6 and IL-10 plasma levels. Moreover, all treatments reversed cortical ICAM-1 mRNA expression and both fucoidan and sulodexide reversed cortical IL-6 and nephrin mRNA expression. Sulodexide decreased renal influx of CD45(+) immune cells whereas renal influx of macrophages and granulocytes remained unaltered for all treatments. Although all compounds inhibited HPSE activity, fucoidan and sulodexide were the most potent inhibitors. Notably, fucoidan and sulodexide decreased LPS-induced mRNA expression of ICAM-1 and IL-6 by cultured glomerular endothelial cells.Conclusion: Our data show a potentially protective effect of glycosaminoglycans and fucoidan in experimental glomerulonephritis. Future research should be aimed at the further identification of defined HS structures that have therapeutic potential in the treatment of glomerular diseases. Show less
In anti-neutrophil cytoplasmic antibody (ANCA)- associated vasculitis (AAV), hematuria and proteinuria are biomarkers reflecting kidney involvement at diagnosis. Yet, the prognostic value of their... Show moreIn anti-neutrophil cytoplasmic antibody (ANCA)- associated vasculitis (AAV), hematuria and proteinuria are biomarkers reflecting kidney involvement at diagnosis. Yet, the prognostic value of their persistence after immunosuppressive induction therapy, reflecting kidney damage or persistent disease, remains uncertain. To study this, our post hoc analysis included participants of five European randomized clinical trials on AAV (MAINRITSAN, MAINRITSAN2, RITUXVAS, MYCYC, IMPROVE). Urine protein-creatinine ratio (UPCR) and hematuria of spot urine samples collected at the end of induction therapy (four-six months after treatment initiation) were correlated with the occurrence of a combined end point of death and/or kidney failure, or relapses during follow-up. Among 571 patients (59% men, median age 60), 60% had anti-proteinase 3-ANCA and 35% had anti- myeloperoxidase-ANCA, while 77% had kidney involvement. After induction therapy, 157/526 (29.8%) had persistent hematuria and 165/481 (34.3%) had UPCR of 0.05 g/mmol or more. After a median follow-up of 28 months (interquartile range 18-42), and adjustment for age, ANCA type, maintenance therapy, serum creatinine and persistent hematuria after induction, a UPCR of 0.05 g/mmol or more after induction was associated with significant risk of death/kidney failure (adjusted Hazard Ratio [HR] 3.06, 95% confidence interval 1.09-8.59) and kidney relapse (adjusted subdistribution HR 2.22, 1.16-4.24). Persistent hematuria was associated with significant kidney relapse (adjusted subdistribution HR 2.16, 1.13-4.11) but not with relapse affecting any organ nor with death/kidney failure. Thus, in this large cohort of patients with AAV, persistent proteinuria after induction therapy was associated with death/kidney failure and kidney relapse, whereas persistent hematuria was an independent predictor of kidney relapse. Hence, these parameters must be considered to assess long-term kidney prognosis of patients with AAV. Show less
Background and objectives In the BLISS-LN study, belimumab improved kidney outcomes in adult patients with active lupus nephritis. This 28-week open-label extension of BLISS-LN assessed belimumab's... Show moreBackground and objectives In the BLISS-LN study, belimumab improved kidney outcomes in adult patients with active lupus nephritis. This 28-week open-label extension of BLISS-LN assessed belimumab's safety and efficacy. Design, setting, participants, & measurements Eligible patients completing BLISS-LN received monthly intravenous belimumab 10 mg/kg plus standard therapy. End points included safety, open-label week 28 primary efficacy renal response (urine protein-creatinine ratio [UPCR] <_0.7, eGFR no more than 20% below open-label baseline value or >_60 ml/min per 1.73 m2, no prohibited medications) and complete renal response (UPCR < 0.5, eGFR no more than 10% below open-label baseline value or >_90 ml/min per 1.73 m2, no prohibited medications), and UPCR and eGFR by visit. Responses were also analyzed post hoc using the double-blind phase criteria. Results Of 257 enrolled patients, 255 were treated (safety population: n=123 switched from placebo-tobelimumab; n=132 remained on belimumab); 245 (97%) patients completed the study. Adverse events and serious adverse events were experienced by 62% and 4% of placebo-to-belimumab patients, respectively, and by 70% and 8% of belimumab-to-belimumab patients, respectively. One death occurred in the placebo-to-belimumab group. From open-label baseline to week 28, increases occurred in the proportions of patients achieving primary efficacy renal response (placebo-to-belimumab: from 60% to 67%; belimumab-to-belimumab: from 70% to 75%) and complete renal response (placebo-to-belimumab: from 36% to 48%; belimumab-to-belimumab: from 48% to 62%). Based on double-blind phase criteria, changes also occurred in the proportions achieving primary efficacy renal response (placebo-to-belimumab: from 54% to 53%; belimumab-to-belimumab: from 66% to 52%) and complete renal response (placebo-to-belimumab: from 34% to 35%; belimumab-to-belimumab: from 46% to 41%). The seeming decrease in response rates in the belimumab-to-belimumab groups was attributed to discontinuations/administration of glucocorticoids for non-SLE reasons as opposed to nephritis. Median UPCR and eGFR values were similar at open-label baseline and week 28. Conclusions No new safety signals were identified, and efficacy was generally maintained throughout the open label phase. contributing the affiliations listed at the article. Correspondence: Dr. Richard Division of Rheumatology, Northwell Donald and Zucker School Medicine, Northwell Suite 302, NY 11021. RFurie@northwell.edu Show less
Gelder, T. van; Lerma, E.; Engelke, K.; Huizinga, R.B. 2022
Introduction Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus. Standard-of-care immunosuppressive therapies achieve poor complete renal response (CRR) rates, with... Show moreIntroduction Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus. Standard-of-care immunosuppressive therapies achieve poor complete renal response (CRR) rates, with considerable toxicity. This article reviews voclosporin, a novel oral calcineurin inhibitor (CNI) approved for treatment in adults with active LN by the US Food and Drug Administration (the FDA) in January 2021. Areas covered This review summarizes the chemical properties, pharmacokinetics, and pharmacodynamics of voclosporin, and its efficacy and safety in LN, based on literature review covering PubMed searches, manufacturers' websites, and documents produced by the FDA. Expert opinion Voclosporin is a CNI with a consistent pharmacokinetic-pharmacodynamic relationship resulting from enhanced calcineurin binding and reduced drug and metabolite load. This profile permits therapeutic efficacy in LN at a dose associated with relatively low calcineurin inhibition, and therefore a potentially improved safety profile. Pivotal trials demonstrated a significant benefit of adding voclosporin to standard therapy, with rapid reduction in proteinuria, and a clinically meaningful and significantly higher CRR rate at 1 year. At approved doses for LN, potential advantages of voclosporin versus historical experience with CNIs include lack of need for therapeutic drug monitoring, benign metabolic, lipid and electrolyte profile, and no impact on mycophenolate mofetil levels. Show less
Gelder, T. van; Lerma, E.; Engelke, K.; Huizinga, R.B. 2022
Introduction Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus. Standard-of-care immunosuppressive therapies achieve poor complete renal response (CRR) rates, with... Show moreIntroduction Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus. Standard-of-care immunosuppressive therapies achieve poor complete renal response (CRR) rates, with considerable toxicity. This article reviews voclosporin, a novel oral calcineurin inhibitor (CNI) approved for treatment in adults with active LN by the US Food and Drug Administration (the FDA) in January 2021. Areas covered This review summarizes the chemical properties, pharmacokinetics, and pharmacodynamics of voclosporin, and its efficacy and safety in LN, based on literature review covering PubMed searches, manufacturers' websites, and documents produced by the FDA. Expert opinion Voclosporin is a CNI with a consistent pharmacokinetic-pharmacodynamic relationship resulting from enhanced calcineurin binding and reduced drug and metabolite load. This profile permits therapeutic efficacy in LN at a dose associated with relatively low calcineurin inhibition, and therefore a potentially improved safety profile. Pivotal trials demonstrated a significant benefit of adding voclosporin to standard therapy, with rapid reduction in proteinuria, and a clinically meaningful and significantly higher CRR rate at 1 year. At approved doses for LN, potential advantages of voclosporin versus historical experience with CNIs include lack of need for therapeutic drug monitoring, benign metabolic, lipid and electrolyte profile, and no impact on mycophenolate mofetil levels. Show less
Lugthart, G.; Jordans, C.C.E.; Pagter, A.P.J. de; Bresters, D.; Jol-van der Zijde, C.M.; Bense, J.E.; ... ; Lankester, A.C. 2021
Chronic kidney disease (CKD) is an important sequela of hematopoietic stem cell transplantation (HSCT), but data regarding CKD after pediatric HSCT are limited. In this single center cohort study,... Show moreChronic kidney disease (CKD) is an important sequela of hematopoietic stem cell transplantation (HSCT), but data regarding CKD after pediatric HSCT are limited. In this single center cohort study, we evaluated the estimated glomerular filtration rate (eGFR) dynamics, proteinuria and hypertension in the first decade after HSCT and assessed risk factors for CKD in 216 pediatric HSCT survivors, transplanted 2002-2012. The eGFR decreased from a median of 148 to 116 ml/min/1.73 m(2) between pre-HSCT to ten years post-HSCT. CKD (KDIGO stages G2 or A2 or more; eGFR under 90 ml/min/1.73 m(2) and/or albuminuria) occurred in 17% of patients. In multivariate analysis, severe prolonged stage 2 or more acute kidney injury (AKI), with an eGFR under 60ml/min/1.73 m(2) and duration of 28 days or more, was the main risk factor for CKD (hazard ratio 9.5, 95% confidence interval 3.4-27). Stage 2 or more AKI with an eGFR of 60ml/min/1.73 m(2) or more and KDIGO stage 2 or more AKI with eGFR under 60ml/min/1.73 m(2) but recovery within 28 days were not associated with CKD. Furthermore, hematological malignancy as HSCT indication was an independent risk factor for CKD. One third of patients had both CKD criteria, one third had isolated eGFR reduction and one third only had albuminuria. Hypertension occurred in 27% of patients with CKD compared to 4.4% of patients without. Tubular proteinuria was present in 7% of a subgroup of 71 patients with available beta 2-microglobulinuria. Thus, a significant proportion of pediatric HSCT recipients developed CKD within ten years. Our data stress the importance of structural long-term monitoring of eGFR, urine and blood pressure after HSCT to identify patients with incipient CKD who can benefit from nephroprotective interventions. Show less
Background Crumbs2 is expressed at embryonic stages as well as in the retina, brain, and glomerular podocytes. Recent studies identified CRB2 mutations as a novel cause of steroid-resistant... Show moreBackground Crumbs2 is expressed at embryonic stages as well as in the retina, brain, and glomerular podocytes. Recent studies identified CRB2 mutations as a novel cause of steroid-resistant nephrotic syndrome (SRNS).Methods To study the function of Crb2 at the renal filtration barrier, mice lacking Crb2 exclusively in podocytes were generated. Gene expression and histologic studies as well as transmission and scanning electron microscopy were used to analyze these Crb2(podKO) knockout mice and their littermate controls. Furthermore, high-resolution expansion microscopy was used to investigate Crb2 distribution in murine glomeruli. For pull-down experiments, live cell imaging, and transcriptome analyses, cell lines were applied that inducibly express fluorescent protein-tagged CRB2 wild type and mutants.Results Crb2(podKO) mice developed proteinuria directly after birth that preceded a prominent development of disordered and effaced foot processes, upregulation of renal injury and inflammatory markers, and glomerulosclerosis. Pull-down assays revealed an interaction of CRB2 with Nephrin, mediated by their extracellular domains. Expansion microscopy showed that in mice glomeruli, Crb2 and Nephrin are organized in adjacent clusters. SRNS-associated CRB2 protein variants and a mutant that lacks a putative conserved O-glycosylation site were not transported to the cell surface. Instead, mutants accumulated in the ER, showed altered glycosylation pattern, and triggered an ER stress response.Conclusions Crb2 is an essential component of the podocyte's slit diaphragm, interacting with Nephrin. Loss of slit diaphragm targeting and increasing ER stress are pivotal factors for onset and progression of CRB2-related SRNS. Show less
Proteinuria develops when specific components in the glomerular filtration barrier have impaired function. Although the precise components involved in maintaining this barrier have not been fully... Show moreProteinuria develops when specific components in the glomerular filtration barrier have impaired function. Although the precise components involved in maintaining this barrier have not been fully identified. heparan sulfate proteoglycans are believed to play an essential role in maintaining glomerular filtration. Although in situ studies have shown that a loss of heparan sulfate glycosaminoglycans increases the permeability of the glomerular filtration barrier. recent studies using experimental models have shown that podocyte-specific deletion of heparan sulfate glycosaminoglycan assembly does not lead to proteinuria. However, tubular reabsorption of leaked proteins might have masked an increase in glomerular permeability in these models. Furthermore, not only podocytes but also glomerular endothelial cells are involved in heparan sulfate synthesis in the glomerular filtration barrier. Therefore, we investigated the effect of a global heparan sulfate glycosaminoglycan deficiency on glomerular permeability. We used a zebrafish embryo model carrying a homozygous germline mutation in the ext2 gene. Glomerular permeability was assessed with a quantitative dextran tracer injection method. In this model, we accounted for tubular reabsorption. Loss of anionic sites in the glomerular basement membrane was measured using polyethyleneimine staining. Although mutant animals had significantly fewer negatively charged areas in the glomerular basement membrane. glomerular permeability was unaffected. Moreover, heparan sulfate glycosaminoglycan-deficient embryos had morphologically intact podocyte foot processes. Glomerular filtration remains fully functional despite a global reduction of heparan sulfate. Show less
Background. The VALidation of IGA (VALIGA) study investigated the utility of the Oxford Classification of immunoglobulin A nephropathy (IgAN) in 1147 patients from 13 European countries.Methods.... Show moreBackground. The VALidation of IGA (VALIGA) study investigated the utility of the Oxford Classification of immunoglobulin A nephropathy (IgAN) in 1147 patients from 13 European countries.Methods. Biopsies were scored by local pathologists followed by central review in Oxford. We had two distinct objectives: to assess how closely pathology findings were associated with the decision to give corticosteroid/immunosuppressive (CS/IS) treatments, and to determine the impact of differences in MEST-C scoring between central and local pathologists on the clinical value of the Oxford Classification. We tested for each lesion the associations between the type of agreement (local and central pathologists scoring absent, local present and central absent, local absent and central present, both scoring present) with the initial clinical assessment, as well as long-term outcomes in those patients who did not receive CS/IS.Results. All glomerular lesions (M, E, C and S) assessed by local pathologists were independently associated with the decision to administer CS/IS therapy, while the severity of tubulointerstitial lesions was not. Reproducibility between local and central pathologists was moderate for S (segmental sclerosis) and T (tubular atrophy/interstitial fibrosis), and poor for M (mesangial hypercellularity), E (endocapillary hypercellularity) and C (crescents). Local pathologists found statistically more of each lesion, except for the S lesion, which was more frequent with central review. Disagreements were more likely to occur when the proportion of glomeruli affected was low. The M lesion, assessed by central pathologists, correlated better with the severity of the disease at presentation and discriminated better with outcomes. In contrast, the E lesion, evaluated by local pathologists, correlated better with the clinical presentation and outcomes when compared with central review. Both C and S lesions, when discordant between local and central pathologists, had a clinical phenotype intermediate to double absent lesions (milder disease) and double present (more severe).Conclusion. We conclude that differences in the scoring of MEST-C criteria between local pathologists and a central reviewer have a significant impact on the prognostic value of the Oxford Classification. Since the decision to offer immunosuppressive therapy in this cohort was intimately associated with the MEST-C score, this study indicates a need for a more detailed guidance for pathologists in the scoring of IgAN biopsies. Show less
