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Over-expression of platelet-derived growth factor in human diabetic nephropathy
Robyn G Langham1, Darren J Kelly, Julie Maguire
1University of Melbourne St Vincent's Hospital Department of Medicine, Fitzroy, Australia. rlangham@medstv.unimelb.edu.au
Background:
The pathogenetic mechanisms responsible for progressive renal impairment of diabetic nephropathy are still poorly understood, despite its growing incidence. Increasing evidence suggests that growth factors may contribute to the initiation and progressive fibrosis of diabetic nephropathy. In this study, the gene expression and protein distribution of platelet-derived growth factor-A and -B (PDGF-A and PDGF-B) in human diabetic nephropathy were examined.
Methods:
PDGF-A and PDGF-B mRNA levels in surplus renal biopsy tissue from seven patients with overt diabetic nephropathy and six nephrectomy samples were examined using quantitative reverse transcription-polymerase chain reaction (RT-PCR). In addition, each sample was also examined immunohistochemically to quantify and localize peptide expression of each PDGF isoform.
Results:
Gene expression of PDGF-A and PDGF-B mRNA were increased 22- and 6-fold, respectively, in biopsies from patients with diabetic nephropathy compared with control tissue. Immunostaining also demonstrated increased peptide expression of both PDGF-A and PDGF-B in diabetic nephropathy, with each isoform showing a specific pattern of tissue distribution.
Conclusions:
The findings of increased gene and protein expression of PDGF in renal biopsies from patients with diabetic nephropathy imply a potential role for this prosclerotic growth factor in the development of the progressive fibrosis that characterizes human diabetic kidney disease.
Insights
Platelet-derived growth factor (PDGF)-A and -B gene and protein expression are elevated in diabetic nephropathy, suggesting a role in kidney fibrosis progression.
Area of Science:
- Nephrology
- Molecular Biology
- Pathogenesis of Kidney Disease
Background:
- Diabetic nephropathy is a leading cause of kidney failure with poorly understood pathogenesis.
- Growth factors are implicated in the development of diabetic nephropathy fibrosis.
- Platelet-derived growth factor (PDGF) is a key growth factor in fibrotic processes.
Purpose of the Study:
- To investigate the gene and protein expression of PDGF-A and PDGF-B in human diabetic nephropathy.
- To determine the localization and distribution of PDGF isoforms in affected kidney tissue.
Main Methods:
- Quantitative reverse transcription-polymerase chain reaction (RT-PCR) to measure PDGF-A and PDGF-B mRNA levels.
- Immunohistochemistry to quantify and localize PDGF-A and PDGF-B peptide expression.
- Analysis of renal biopsy tissue from diabetic nephropathy patients and control samples.
Main Results:
- PDGF-A mRNA levels increased 22-fold and PDGF-B mRNA levels increased 6-fold in diabetic nephropathy biopsies compared to controls.
- Immunostaining confirmed increased peptide expression of both PDGF-A and PDGF-B in diabetic nephropathy.
- Both PDGF isoforms exhibited distinct tissue distribution patterns in affected kidneys.
Conclusions:
- Elevated gene and protein expression of PDGF in diabetic nephropathy indicates its potential involvement in progressive renal fibrosis.
- PDGF may act as a prosclerotic growth factor contributing to the pathogenesis of diabetic kidney disease.
- Further research into PDGF's role could lead to novel therapeutic strategies for diabetic nephropathy.