The role of immune cells infiltrating the kidney in the pathogenesis of salt-sensitive hypertension.

This work summarizes recent evidence that suggests that renal infiltration with immune cells plays a role in the pathogenesis of salt-sensitive hypertension. The presence of immunocompetent cells is a conspicuous finding in conditions associated with hypertension induced or maintained by a high salt intake. Studies in models of salt-sensitive hypertension following angiotensin II infusion and nitric oxide synthesis inhibition indicate that a reduction in the tubulointerstitial infiltration of lymphocytes and macrophages during the induction period results in protection from the subsequent development of salt-sensitive hypertension. Reduction of the renal immune infiltrate in spontaneously hypertensive rats results in near normalization of the blood pressure. The reduction in the immune infiltrate is associated with a reduction in the number of cells expressing angiotensin II (some of which are immune cells) and a reduction in renal oxidative stress. Since increased intrarenal angiotensin activity tends to reduce filtered sodium and increase sodium reabsorption, and the tubulointerstitial damage resulting from oxidative stress can induce a shift to the right in the pressure-natriuresis relationship, these findings suggest potential mechanisms by which the immune infiltrate could induce or worsen salt-driven hypertension.