Publication Date:
2012-09-02
Description:
Aims The aim of this study was to investigate the role of cyclooxygenase (COX)-1 on vascular alterations in structure, mechanics, and extracellular matrix (ECM) components induced by angiotensin (Ang) II in mesenteric arteries from wild-type (WT) and COX-1 knockout ( COX-1 –/– ) mice. Methods and results Animals were infused with vehicle or Ang II (400 ng/kg/min, s.c.) ± SC-560 ( COX-1 inhibitor), DFU (COX-2 inhibitor), or SQ-29548 (TP receptor antagonist). After 2 weeks, vessels were isolated and exposed to intraluminal pressures (3–140 mmHg, pressurized myograph) to determine mechanical properties. Angiotensin II-induced vascular hypertrophic remodelling in WT was reversed by SC-560 or SQ-29548, but unaffected by DFU. Angiotensin II increased vessel stiffness ( P 〈 0.01), this effect being ameliorated by SC-560 or SQ-29548, but unmodified by DFU. Angiotensin II failed to modify vessel elasticity in COX-1 –/– mice. In WT vessels, Ang II enhanced COX-1 immunostaining, induced collagen and fibronectin depositions and decreased elastin content ( P 〈 0.01). These effects were reversed by SC-560 or SQ-29548, but unaffected by DFU. In COX-1 –/– mice, Ang II did not affect ECM contents. In WT, Ang II increased COX-1 and decreased COX-2 expression, and enhanced the vascular release of 6-keto-PGF1α which was prevented by COX-1 blockade. Human coronary artery smooth muscle cells, incubated with Ang II, showed an increased expression of procollagen I, which was abrogated by SC-560 or SQ-29548. Conclusion Angiotensin II-induced alterations of resistance arteries in structure, mechanics, and ECM composition were prevented by COX-1 inhibition and TP receptor antagonism, indicating that Ang II-mediated vascular damage is mediated by COX-1-derived prostanoid prostacyclin, activating TP receptors.
Print ISSN:
0195-668X
Electronic ISSN:
1522-9645
Topics:
Medicine
Permalink
