ATUBULAR GLOMERULI AND GLOMERULAR CYSTS - A POSSIBLE PATHWAY FOR NEPHRON LOSS IN THE HUMAN KIDNEY

Glomerular tufts were removed and scanning electron microscopy was use d to study the interior of Bowman's capsule, in order to identify atub ular glomeruli, Normal renal cortex was studied from six kidneys remov ed for tumour and six renal transplants removed for end-stage rejectio n, Atubular glomeruli occurred in normal renal cortex in less than 1 p ercent of glomeruli, but were more common in transplant nephropathy, r epresenting up to 61 percent of glomeruli. Glomerular cysts were ident ified which also lacked a tubular connection, Both atubular glomeruli and glomerular cysts contained a contracted glomerular capillary tuft and in both, Bowman's capsule was lined mostly by parietal podocytes. It is suggested that atubular glomeruli may be precursors of the glome rular cysts, The glomerular tuft may produce filtrate which exits the glomerulus via the parietal podocytes on Bowman's capsule. In normal h uman kidney, the formation of atubular glomeruli by disconnection from the tubule may represent an alternative pathway for the gradual nephr on loss that is associated with ageing, This process may be amplified in disease: disconnection from the tubule may be an important part of irreversible nephron damage in chronic allograft nephropathy.