Related Experiment Videos
Studies of glomerular permeability factor (GPF) in focal segmental glomerular sclerosis and the relationship between
S Kondo1, N Yoshizawa, Y Kusumi
1Department of Public Health, National Defense Medical College, Saitama, Japan.
Background:
We previously demonstrated that the supernatants of cultured concanavalin-A (con-A) stimulated peripheral blood mononuclear cells (PBMC) from patients with minimal change nephrotic syndrome (MCNS) increased the urinary protein excretion in injected rats and suggested that PBMC released a factor, which we called glomerular permeability factor (GPF), changes in the glomerular permeability and thus resulted in proteinuria in MCNS.
Material And Methods:
In this study we investigated the GPF activity in focal segmental glomerular sclerosis (FGS) and other conditions of chronic glomerulonephritis (CGN), and also the relationship between GPF and vascular permeability factor (VPF). In experiment 1 the supernatants of the cultured con-A stimulated PBMC from patients with 10 FGS, 5 other CGN and 10 controls were tested regarding their ability to produce GPE The GPF activity was defined as positive when the 8-hour urinary protein excretion after the injection of the supernatant in Sprague-Dawley rats exceeded the mean value plus 2 standard deviations (M + 2 SD) of that before injection.
Results:
Three out of 10 FGS patients and 1 membranous nephropathy patient out of the 5 other CGN patients were positive for GPF activity. In experiment 2 the relationship between GPF and VPF was analyzed using culture supernatants of PBMC from 10 nephrotic MCNS patients and 15 controls. The VPF activity was measured following the method developed by Ovary [1975]. All 7 cases that were positive for GPF activity were simultaneously positive for VPF activity. On the other hand, 16 cases that were positive for VPF activity were not always positive for GPF activity (7 cases were positive and 9 were negative for VPF activity).
Conclusion:
Experiments 1 and 2 thus suggested that GPF was not active in MCNS alone, but also in other CGN conditions and it was therefore not considered to be the same factor/substance(s) as VPF.
Insights
Glomerular permeability factor (GPF) is present in minimal change nephrotic syndrome and other chronic glomerulonephritis conditions. GPF is distinct from vascular permeability factor (VPF), suggesting different roles in kidney disease.
Area of Science:
- Nephrology
- Immunology
- Pathophysiology
Background:
- Previous research indicated peripheral blood mononuclear cells (PBMC) release glomerular permeability factor (GPF) in minimal change nephrotic syndrome (MCNS), causing proteinuria.
- GPF was hypothesized to increase glomerular permeability, leading to urinary protein excretion in MCNS patients.
Purpose of the Study:
- To investigate GPF activity in focal segmental glomerulosclerosis (FGS) and other chronic glomerulonephritis (CGN) conditions.
- To determine the relationship between GPF and vascular permeability factor (VPF).
Main Methods:
- Supernatants from concanavalin-A stimulated PBMC of patients with FGS, other CGN, and controls were tested for GPF activity in rats.
- GPF activity was defined by increased urinary protein excretion in injected rats.
- VPF activity was measured, and its relationship with GPF was analyzed in MCNS patients and controls.
Main Results:
- GPF activity was detected in 3 out of 10 FGS patients and 1 out of 5 other CGN patients.
- All 7 cases positive for GPF activity were also positive for VPF activity.
- However, not all VPF-positive cases were GPF-positive, indicating a distinction between the factors.
Conclusions:
- GPF activity is present not only in MCNS but also in other CGN conditions.
- GPF is not identical to VPF, suggesting distinct biological roles.
- These findings contribute to understanding the pathogenesis of proteinuric kidney diseases.