Amyloid-containing renal interstitial cell nodules (RICNs) associated with chronic arterial hypertension in older age groups.

A highly significant correlation is demonstrated between the presence in older persons of medullary renal interstitial cell nodules (RICNs) containing amyloid and increased heart weight indicative of chronic arterial hypertension. By contrast, the population with amyloid-free RICNs 1) showed heart weights comparable to those of controls and 2) had a mean age about 11 years less (56.7 +/- 9.6 vs 68 +/- 12 years) than the group with amyloid-containing RICNs. In a series of 55 autopsy cases presenting with RICNs, no individual was younger than 30 years. In two cases, in which fresh material was available, histochemical reactions suggested that the RICNs contained APUD amyloid. It is speculated that fully functional RICNs may evolve on a compensatory base counteracting an increase in mean arterial blood pressure and that the deposition of amyloid within RICNs could be associated with, or be an expression of, a reduced endocrine function of these structures, finally resulting in the development of arterial hypertension.