Endothelial and platelet reactions in the idiopathic nephrotic syndrome: an ultrastructural study

In this ultrastructural study we have critically examined blood vascular reactions in the glomerular microcirculation of 14 patients with idiopathic membranous nephropathy and 11 patients with minimal change disease. In all patients, bullous intracellular edema was observed in the glomerular endothelium, a change interpreted as reflecting endothelial injury. Platelets in various stages of degranulation were seen in relation to the endothelium. In ten biopsy specimens platelet aggregates were observed. Platelets with exhausted secretory products ("ghosts") were frequently identified in areas contiguous with other obvious degranulating platelets. In some cases, pseudopodia of degranulating platelets were observed in direct contact with the glomerular basement membrane in areas denuded of endothelium. Tactoids of fibrin were seen in nine cases in relation to degranulating platelets or edematous endothelium, or both. Our data suggest that these endothelial and platelet reactions play a role in the pathophysiology oi the nephrotic syndrome in patients with minimal change disease or idiopathic membranous nephropathy.