Renin inhibition reduces hypercholesterolemia-induced atherosclerosis in mice

Area of Science:

• Cardiovascular Research
• Molecular Biology
• Immunology

Background:

• The renin-angiotensin system (RAS) plays a complex role in atherosclerosis.
• Renin is the key enzyme initiating angiotensin peptide production.
• Understanding RAS components in macrophages is crucial for atherosclerosis research.

Purpose of the Study:

• To investigate the impact of renin inhibition on atherosclerosis using a mouse model.
• To elucidate the role of macrophage-derived angiotensin in atherosclerotic lesion development.
• To determine the mechanism by which renin influences atherogenesis.

Main Methods:

• Administration of the renin inhibitor aliskiren to fat-fed Ldlr(-/-) mice.
• Bone marrow transplantation experiments using renin-deficient and angiotensin II type 1a receptor-deficient bone marrow.
• In vitro studies involving macrophage and endothelial cell co-cultures.

Main Results:

• Aliskiren treatment markedly reduced atherosclerotic lesion size in the aortic arch and root.
• Transplantation of renin-deficient bone marrow significantly decreased lesion size.
• Macrophage-derived angiotensin did not appear to act in an autocrine/paracrine fashion.
• Renin-expressing macrophages enhanced monocyte adhesion to endothelial cells in vitro.

Conclusions:

• Renin inhibition is a potent strategy for reducing atherosclerosis.
• Macrophage-derived renin is not the primary driver of atherosclerosis via autocrine/paracrine signaling.
• Renin-dependent processes in macrophages influence early atherogenic events like monocyte adhesion.