Immunolocalization of renal kallikrein-like substance in rat urinary bladder

Abstract

The renal origin of kallikrein is now clearly established. However, the presence of kallikrein in urine raises questions about a possible physiological role of this enzyme at the urinary level. We have already demonstrated the presence of kallikrein-like substance in rat ureter. For establishing the continuity of the presence of kallikrein-like substance along the urinary tract we have studied the localization of immunoreactive kallikrein-like substance in urinary bladder of the normal rat by immunohistochemical methods for light- and electron-microscopy, using an antibody against rat urinary kallikrein. By light microscopy, kallikrein-like substance was found to be associated with the lamina propria, which is the connective tissue component which constitutes one layer of the bladder wall. Weak staining was present in the smooth-muscle layer. By immuno-electron microscopy, kallikrein-like substance was localized in fibroblasts which were present in the connective tissue and which penetrated into the layer of smooth muscle; immunoreactivity was observed in endoplasmic reticulum, Golgi apparatus and free polyribosomes. Immunolabelling was demonstrated in no other part of the wall bladder and in no other cellular component. The continuity of the presence of kallikrein-like substance from the kidney to the urinary bladder gives new indications concerning the significance of this system in renal physiology.

The Kallikrein-Kinin System: A Novel Mediator of IL-17-Driven Anti-Candida Immunity in the Kidney

“…Only kidney-resident cells, particularly renal tubular epithelial cells (RTEC), expressed Klk1 during infection (Fig 2A). These results agree with previous reports indicating that RTEC are the major producers of Klk1 in chronic kidney diseases [34,35]. Although Klk1 controls vital kidney functions, its regulation and function under inflammatory conditions are not well defined.…”