Molecular approaches to the study of renal disease

Summary: Recent developments in cell biology and molecular biology have provided new techniques for molecular studies on renal diseases. the in situ hybridization technique demonstrates the site and the degree of gene expression of various cytokines and regulating proteins associated with the altered function of the glomeruli. It is not known, however, if the expression of these genes is different among various glomerular diseases. the aim of this study was to elucidate the disease specific phenomena in glomerular gene expression. Renal biopsy specimens were obtained from patients with diabetic nephropathy, and IgA nephropathy. the degree of tissue damage as well as the levels of various clinical parameters were matched between these two groups. In situ hybridization of mRNA in renal tissues for transforming growth factor (TGF)-β, storomelysin (MMP-3) and tissue inhibitor of metalloproteinase (TIMP-1) were performed using nonradioactive digoxigenin (DIG)-labelled oligonucleotide probes. In parallel studies, renal biopsy specimens were stained with monoclonal antibody against advanced glycated end-products (AGE). the results demonstrated that the distribution of mRNA expression of TGF-β was similar between these two diseases, but the expression of MMP-3 and TIMP-1 was parallel with the degree of tissue damage in patients with IgA nephropathy while it was diminished in patients with an advanced degree of tissue damage due to diabetic nephropathy. Positive staining of renal tissues with anti-AGE antibody was only observed in patients with diabetic nephropathy. It is concluded that glycation of renal structural proteins might interfere with their metabolism by enzymes and their inhibitors, while a cytokine responsible for mesangial expansion was similarly expressed.