Selective blockade of endothelin-B receptor improves survival of critically perfused musculocutaneous flaps

Endothelin-a receptor antagonism after renal angioplasty enhances renal recovery in renovascular disease

Percutaneous transluminal renal angioplasty/stenting (PTRAS) is frequently used to treat renal artery stenosis and renovascular disease (RVD); however, renal function is restored in less than one half of the cases. This study was designed to test a novel intervention that could refine PTRAS and enhance renal recovery in RVD. Renal function was quantified in pigs after 6 weeks of chronic RVD (induced by unilateral renal artery stenosis), established renal damage, and hypertension. Pigs with RVD then underwent PTRAS and were randomized into three groups: placebo (RVD+PTRAS), chronic endothelin-A receptor (ET-A) blockade (RVD+PTRAS+ET-A), and chronic dual ET-A/B blockade (RVD+PTRAS+ET-A/B) for 4 weeks. Renal function was again evaluated after treatments, and then, ex vivo studies were performed on the stented kidney. PTRAS resolved renal stenosis, attenuated hypertension, and improved renal function but did not resolve renal microvascular rarefaction, remodeling, or renal fibrosis. ET-A blocker therapy after PTRAS significantly improved hypertension, microvascular rarefaction, and renal injury and led to greater recovery of renal function. Conversely, combined ET-A/B blockade therapy blunted the therapeutic effects of PTRAS alone or PTRAS followed by ET-A blockade. These data suggest that ET-A receptor blockade therapy could serve as a coadjuvant intervention to enhance the outcomes of PTRAS in RVD. These results also suggest that ET-B receptors are important for renal function in RVD and may contribute to recovery after PTRAS. Using clinically available compounds and techniques, our results could contribute to both refinement and design of new therapeutic strategies in chronic RVD.

Endothelin-1 in peripheral arterial disease: a potential role in muscle damage

The evidence for the role of endothelin-1 (ET-1) in endothelial dysfunction and atherosclerosis has been growing since its discovery. However most studies have focussed on cardiac disease and its role in peripheral arterial disease (PAD) is less clear. In addition to its role in the development and progression of atherosclerotic lesions in lower limb arteries, there is evidence that ET-1 adversely affects microvessels within the muscle and the viability of the ischemic muscle itself. This review summarises some of these findings which underscore the potential use of ET antagonists as an adjunct in the treatment of PAD.