Tubulo-interstitial lesions in glomerulopathy. I. Pathogenesis

Glomerulopathies (GLN) are at the focus of interest of nephropathologist. As the name implies, the glomeruli are most characteristically affected. Beside glomeruli, also tubules and interstitium are important participants in renal scarring. It is believed that its chief determinant is proteinuria. The presence of protein in the urine activates tubular epithelial cells and induces production of mediators, the most important being TGF-beta. Subsequently, the interstitial cells are activated and acquire the myofibroblast phenotype. The myofibroblasts produce and deposit connective tissue matrix, resulting in morphologically visible scarring.