The renin-secreting cell in polyarteritis--an immunocytochemical study

Area of Science:

• Nephrology
• Immunohistochemistry
• Renal Pathology

Background:

• Polyarteritis, a vasculitis affecting medium-sized arteries, can involve renal arteries.
• Renal artery stenosis and ischemia trigger the renin-angiotensin system, impacting blood pressure.
• Immunocytochemistry allows visualization of specific cellular components, such as renin.

Purpose of the Study:

• To investigate the distribution and abundance of renin-containing cells in kidney sections from patients with polyarteritis.
• To compare the renin cell distribution in polyarteritis with changes observed in renal artery stenosis.
• To explore the potential role of the renin-angiotensin system in the pathogenesis of hypertension associated with polyarteritis.

Main Methods:

• Immunocytochemical staining was used to detect immunoreactive renin in kidney sections from 15 patients with polyarteritis.
• Kidney sections were analyzed for the presence and distribution of renin-containing cells, particularly in juxtaglomerular apparatuses.
• Histological examination identified areas of renal cortex with evidence of ischemia.

Main Results:

• Classical polyarteritis nodosa cases showed hyperplasia of renin cells in ischemic renal cortex, mimicking renal artery stenosis.
• A loss or reversal of the normal superficial-to-deep cortex gradient of renin cells was observed in ischemic areas.
• Microscopic polyarteritis cases exhibited fewer renin-containing cells than normal, suggesting renin synthesis suppression.

Conclusions:

• Focal ischemia in classical polyarteritis nodosa activates the renin-angiotensin system, potentially contributing to hypertension.
• The observed renin cell changes in classical polyarteritis are analogous to those in renal artery stenosis.
• Microscopic polyarteritis appears to involve suppression of renin synthesis, indicated by reduced renin cell counts.