The renal artery ostium flow diverter: structure and potential role in atherosclerosis.

Initiation of renal atherosclerosis occurs primarily at the caudal region of the renal artery ostium. To date, no mechanism for initiation of atherosclerosis at this site has been substantiated. Herein, we identify a renal artery flow diverter on the caudal wall of the renal artery ostium that directs flow into the renal artery and selectively retains LDL, an initial step in atherosclerosis. High-resolution ultrasound revealed the generation of flow eddies by the caudal diverter in vivo, consistent with a role in directing aortic flow to the renal artery. Two-photon excitation en face microscopy of the diverter revealed a substantial reduction in the elastic lamina exposing potential retention sites for LDL. Fluorescent LDL was selectively retained by the renal artery diverter, consistent with its molecular structure. We propose that the rigid macromolecular structure of the renal artery ostium diverter is required for its vascular function and contributes to the initiation of renal atherosclerosis by the retention of LDL.