ACTIVATION OF MESSENGER-RNA EXPRESSION OF COLLAGEN, COLLAGENASE AND ITS INHIBITOR ON RENAL BIOPSY SPECIMENS IN PATIENTS WITH IGA NEPHROPATHY

In situ hybridization of mRNA for collagen IV, collagen VI, stromelysi n (MMP-3) and TIMP1 was examined in renal biopsy specimens from patien ts with IgA nephropathy (IgAN) or diabetic nephropathy with various de grees of tissue damage. The majority of cells in the glomeruli express ed these mRNA almost simultaneously, but a few cells demonstrated posi tive expression for only one of these probes. There was a parallel rel ationship between the degree of tissue damage and that of mRNA express ions of these probes in patients with IgAN, while patients with diabet ic nephropathy showed a reverse relationship between these two paramet ers. It is concluded that patients with mesangial proliferative glomer ulonephritis expressed mRNA for collagen collagenase and its inhibitor in the glomeruli in parallel with the progress of tissue damage. In c ontrast, glomerular samples from patients with diabetic nephropathy sh owed that there was an inverse relationship between tissue damage and expression of mRNA. It is concluded that expression of collagen, colla genase and its inhibitor parallels the progression of glomerular chang es in IgAN, but such parallel expression was not observed in patients with diabetic nephropathy.