Chronic administration of BMS309403 improves endothelial function in apolipoprotein E-deficient mice and in cultured human endothelial cells

Background and purpose: Adipocyte fatty acid-binding protein (A-FABP) is up-regulated in regenerated endothelial cells and modulates inflammatory responses in macrophages. Endothelial dysfunction accompanying regeneration is accelerated by hyperlipidaemia. Here, we investigate the contribution of A-FABP to the pathogenesis of endothelial dysfunction in the aorta of apolipoprotein E-deficient (ApoE(-/-) ) mice and in cultured human endothelial cells.

Experimental approach: A-FABP was measured in aortae of ApoE(-/-) mice and human endothelial cells by RT-PCR, immunostaining and immunoblotting. Total and phosphorylated forms of endothelial nitric oxide synthase (eNOS) were measured by immunoblotting. Changes in isometric tension were measured in rings of mice aortae

Key results: A-FABP was expressed in aortic endothelium of ApoE(-/-) mice aged 12 weeks and older, but not at 8 weeks or in C57 wild-type mice. Reduced endothelium-dependent relaxations to acetylcholine, UK14304 (selective α(2) -adrenoceptor agonist) and A23187 (calcium ionophore) and decreased protein presence of phosphorylated and total eNOS were observed in aortae of 18 week-old ApoE(-/-) mice compared with age-matched controls. A 6 week treatment with the A-FABP inhibitor, BMS309403, started in 12 week-old mice, improved endothelial function, phosphorylated and total eNOS and reduced plasma triglyceride levels but did not affect endothelium-independent relaxations. The beneficial effect of BMS309403 on UK14304-induced relaxations was attenuated by Pertussis toxin. In cultured human microvascular endothelial cells, lipid-induced A-FABP expression was associated with reduced phosphorylated eNOS and NO production and was reversed by BMS309403.

Conclusions and implications: Elevated expression of A-FABP in endothelial cells contributes to their dysfunction both in vivo and in vitro.