Astrocytes and the Renin Angiotensin System: Relevance in Disease Pathogenesis

The presence of a brain renin angiotensin system (RAS) is well documented. An overactive brain RAS contributes to the development and progression of cardiovascular and renal disorders among other conditions. In hypertension, an augmented brain RAS leads to an increase in sympathetic nervous system activity. In addition, impaired baroreceptor reflex function, increased vasopressin activity and neuroinflammation are important contributors as well. The relevance of angiotensins in central and peripheral systems, such as neurons and vascular smooth muscle cells, in cardiovascular disease pathogenesis is fairly understood. However, the role of astrocytes is less well studied. Astrocytes are a major contributor to neuroinflammation by increased synthesis and secretion of inflammatory mediators, dysregulated astrogliosis and impaired astrocyte proliferation. Astrocytes may also contribute to impaired neuromodulation. The precise molecular mechanisms by which astrocytes mediate these effects are still not fully understood. Here, we summarize the role of astrocytes in RAS -mediated pathogenesis of hypertension and other cardiovascular diseases.