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Studies of a glomerular permeability factor in patients with minimal-change nephrotic syndrome
N Yoshizawa1, Y Kusumi, K Matsumoto
1Second Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
Abstract:
Peripheral blood mononuclear cells (PBMC) from patients with minimal-change nephrotic syndrome (MCNS) were tested for their ability to produce a factor which increases the urinary protein excretion levels of rats. It was shown that enhanced proteinuria can be produced in 8-hour urine specimens from rats by the injection of concentrated supernatants of cultured concanavalin-A-stimulated PBMC of patients with MCNS, but not from other nephrotics or normal subjects. The increase in urinary protein excretion was associated with a significant alteration of glomerular epithelial cells similar to that seen in MCNS. These results suggest that in MCNS, PBMC release a factor, which we termed a glomerular permeability factor (GPF), causing changes in glomerular permeability with resulting proteinuria.
Insights
Peripheral blood mononuclear cells (PBMC) from minimal-change nephrotic syndrome (MCNS) patients release a factor that causes proteinuria in rats. This factor, termed glomerular permeability factor (GPF), alters glomerular cells, mimicking MCNS.
Area of Science:
- Nephrology
- Immunology
- Cell Biology
Background:
- Minimal-change nephrotic syndrome (MCNS) is a leading cause of nephrotic syndrome in children.
- The underlying mechanisms causing glomerular injury in MCNS remain incompletely understood.
Purpose of the Study:
- To investigate the potential role of peripheral blood mononuclear cells (PBMC) in MCNS pathogenesis.
- To identify if PBMC from MCNS patients produce a factor that induces proteinuria.
Main Methods:
- Culturing concanavalin-A-stimulated PBMC from MCNS patients, other nephrotic patients, and normal subjects.
- Collecting and concentrating supernatants from cultured PBMC.
- Injecting concentrated supernatants into rats and measuring urinary protein excretion over 8 hours.
- Examining glomerular epithelial cell morphology in rats.
Main Results:
- Supernatants from MCNS patient PBMC significantly increased urinary protein excretion in rats.
- This effect was not observed with PBMC from other nephrotic patients or normal subjects.
- Rats injected with MCNS PBMC supernatants showed glomerular epithelial cell alterations similar to MCNS.
Conclusions:
- PBMC from MCNS patients release a factor, named glomerular permeability factor (GPF).
- GPF increases glomerular permeability, leading to proteinuria characteristic of MCNS.
- This finding suggests a potential autoimmune mechanism involving PBMC in MCNS.