Perivascular adipose tissue (PVAT) is now recognized as an active player in vascular homeostasis. The expansion of PVAT in obesity and its possible role in vascular dysfunction have attracted much interest. In terms of the regulation of vascular tone and blood pressure, PVAT has been shown to release vasoactive mediators, for instance, angiotensin peptides, reactive oxygen species, chemokines and cytokines. The secretory profile of PVAT is altered by obesity, hypertension and other cardiovascular diseases, leading to an imbalance between its pro-contractile and anti-contractile effects. PVAT adipocytes represent an important source of the mediators, but infiltrating immune cells may become more important under conditions of hypoxia and inflammation. This review describes recent advances in the effects of PVAT on the regulation of vascular tone, highlighting the evidence for a procontractile action in health and disease. The role of the endothelium, vascular smooth muscle, immune cells and probably perivascular nerves in PVAT function is also discussed.

Purpose To describe the ultrastructural changes in the choroid of long‐term hipercholesterolemic rabbits after a low dose statin treatment and to evaluate some pleiotropic effects of these drugs on the morphology of endotehlial cells (EC) and vascular smooth muscle cells (VSMC). Methods New Zealand rabbits were divided into three groups: G0, fed a standard diet; G1, fed a 0.5% cholesterol‐enriched diet for 8 months; and G2, fed a 0.5% cholesterol‐enriched diet for 8 months plus administration of fluvastatin sodium or pravastatin sodium at a dose of 2 mg/Kg/day each. Eyes were processed for transmission‐electron microscopy. Results G1 had a build‐up of lipids at the suprachoroidea that compressed the vascular layers with the lumens of the vessels to the point of collapse in some instances. In contrast, G2 had a substantially decreased number of suprachoroidal foam cells and of lipids in the vascular layers and the vascular lumens were normal. The preservation of cytoplasmic organelles, caveolar system and other ultrastructural features of EC and VSMC in G2 was in contrast to the numerous signs of necrosis observed in G1. Bruch’s membrane in G2 contained fewer lipids and more collagen than in G1. Conclusion Treatment with a low dose of fluvastatin sodium or pravastatin sodium reduced the build‐up of lipids and the macrophages in the choroid and restores the vascular lumens of choroidal vessels independently of the cholesterol effect. The normal ultrastructural features of choroidal EC and VSMC in statins treated animals suggest that the endothelial function is preserved and the ischemia reduced.