8 research outputs found
A Novel CLCN5 Mutation Associated With Focal Segmental Glomerulosclerosis and Podocyte Injury
Introduction: Tubular dysfunction is characteristic of Dent's disease; however, focal segmental glomerulosclerosis (FSGS) can also be present. Glomerulosclerosis could be secondary to tubular injury, but it remains uncertain whether the CLCN5 gene, which encodes an endosomal chloride and/or hydrogen exchanger, plays a role in podocyte biology. Here, we implicate a role for CLCN5 in podocyte function and pathophysiology.Methods: Whole exome capture and sequencing of the proband and 5 maternally-related family members was conducted to identify X-linked mutations associated with biopsy-proven FSGS. Human podocyte cultures were used to characterize the mutant phenotype on podocyte function.Results: We identified a novel mutation (L521F) in CLCN5 in 2 members of a Hispanic family who presented with a histologic diagnosis of FSGS and low-molecular-weight proteinuria without hypercalciuria. Presence of CLCN5 was confirmed in cultured human podocytes. Podocytes transfected with the wild-type or the mutant (L521F) CLCN5 constructs showed differential localization. CLCN5 knockdown in podocytes resulted in defective transferrin endocytosis and was associated with decreased cell proliferation and increased cell migration, which are hallmarks of podocyte injury.Conclusions: The CLCN5 mutation, which causes Dent's disease, may be associated with FSGS without hyercalcuria and nepthrolithiasis. The present findings supported the hypothesis that CLCN5 participates in protein trafficking in podocytes and plays a critical role in organizing the components of the podocyte slit diaphragm to help maintain normal cell physiology and a functional filtration barrier. In addition to tubular dysfunction, mutations in CLCN5 may also lead to podocyte dysfunction, which results in a histologic picture of FSGS that may be a primary event and not a consequence of tubular damage
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Association of COVID-19 Versus COVID-19 Vaccination With Kidney Function and Disease Activity in Primary Glomerular Disease: A Report of the Cure Glomerulonephropathy Study
Patients with glomerular disease (GN) may be at increased risk of severe COVID-19, yet concerns over vaccines causing disease relapse may lead to vaccine hesitancy. We examined the associations of COVID-19 with longitudinal kidney function and proteinuria and compared these to similar associations with COVID-19 vaccination.
Observational cohort study from July 1, 2021 to Jan. 1, 2023.
& Participants: A prospective observational study network of 71 centers from North America and Europe (CureGN) with children and adults with primary minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy.
COVID-19 and COVID-19 vaccination.
Repeated measure of estimated glomerular filtration rate (eGFR); recurrent time-to-event outcome of GN disease worsening as defined by doubling of UPCR to at least 1.5g/g or increase in dipstick urine protein by two ordinal levels to 3+ (300mg/dL) or above.
Interrupted time series analysis for eGFR. Prognostic matched sequential stratification recurrent event analysis for GN disease worsening.
Among 2,055 participants, 722 (35%) reported COVID-19; of these, 92 (13%) were hospitalized and 3 died (<1%). eGFR slope pre-COVID-19 was -1.40ml/min/1.73m2 (SD 0.29), and -4.26ml/min/1.73m2 (SD 3.02) within 6 months post-COVID-19, which were not significantly different (p=0.34). COVID-19 was associated with increased risk of worsening GN disease activity (HR 1.35, 95% CI 1.01-1.80). Vaccination was not associated with change in eGFR (-1.34ml/min/1.73m2, SD 0.15 vs -2.16ml/min/1.73m2, SD 1.74; p=0.6) or subsequent GN disease worsening (HR 1.02, 95% CI 0.79–1.33) in this cohort.
Infrequent or short follow-up.
Among patients with primary GN, COVID-19 was severe for 1 in 8 cases and was associated with subsequent worsening of GN disease activity, as defined by proteinuria. In contrast, vaccination against COVID-19 was not associated with change in disease activity or kidney function decline. These results support COVID-19 vaccination for patients with GN.
In this cohort study of 2,055 patients with minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy, COVID-19 resulted in hospitalization or death for 1 in 8 cases and was associated with a 35% increase in risk for worsening proteinuria. In contrast, vaccination did not appear to adversely affect kidney function or proteinuria. Our data support vaccination for COVID-19 in patients with glomerular disease
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CureGN Study Rationale, Design, and Methods: Establishing a Large Prospective Observational Study of Glomerular Disease
Glomerular diseases, including minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, and immunoglobulin A (IgA) nephropathy, share clinical presentations, yet result from multiple biological mechanisms. Challenges to identifying underlying mechanisms, biomarkers, and new therapies include the rarity of each diagnosis and slow progression, often requiring decades to measure the effectiveness of interventions to prevent end-stage kidney disease (ESKD) or death.
Multicenter prospective cohort study.
Cure Glomerulonephropathy (CureGN) will enroll 2,400 children and adults with minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy (including IgA vasculitis) and a first diagnostic kidney biopsy within 5 years. Patients with ESKD and those with secondary causes of glomerular disease are excluded.
Clinical data, including medical history, medications, family history, and patient-reported outcomes, are obtained, along with a digital archive of kidney biopsy images and blood and urine specimens at study visits aligned with clinical care 1 to 4 times per year.
Patients are followed up for changes in estimated glomerular filtration rate, disease activity, ESKD, and death and for nonrenal complications of disease and treatment, including infection, malignancy, cardiovascular, and thromboembolic events.
The study design supports multiple longitudinal analyses leveraging the diverse data domains of CureGN and its ancillary program. At 2,400 patients and an average of 2 years’ initial follow-up, CureGN has 80% power to detect an HR of 1.4 to 1.9 for proteinuria remission and a mean difference of 2.1 to 3.0mL/min/1.73m2 in estimated glomerular filtration rate per year.
Current follow-up can only detect large differences in ESKD and death outcomes.
Study infrastructure will support a broad range of scientific approaches to identify mechanistically distinct subgroups, identify accurate biomarkers of disease activity and progression, delineate disease-specific treatment targets, and inform future therapeutic trials. CureGN is expected to be among the largest prospective studies of children and adults with glomerular disease, with a broad goal to lessen disease burden and improve outcomes