Role of COX-2-derived PGE2 on Vascular Stiffness and Function in Hypertension

Background And Purpose: Prostanoids derived from COX-2 and EP receptors are involved in vascular remodelling in different cardiovascular pathologies. This study evaluates the contribution of COX-2 and EP1 receptors to vascular remodelling and function in hypertension.

Experimental Approach: Spontaneously hypertensive rats (SHR) and angiotensin II (AngII)-infused (1.44 mg · kg(-1) · day(-1), 2 weeks) mice were treated with the COX-2 inhibitor celecoxib (25 mg · kg(-1) · day(-1) i.p) or with the EP1 receptor antagonist SC19220 (10 mg · kg(-1) · day(-1) i.p.). COX-2(-/-) mice with or without AngII infusion were also used.

Key Results: Celecoxib and SC19220 treatment did not modify the altered lumen diameter and wall : lumen ratio in mesenteric resistance arteries from SHR-infused and/or AngII-infused animals. However, both treatments and COX-2 deficiency decreased the augmented vascular stiffness in vessels from hypertensive animals. This was accompanied by diminished vascular collagen deposition, normalization of altered elastin structure and decreased connective tissue growth factor and plasminogen activator inhibitor-1 gene expression. COX-2 deficiency and SC19220 treatment diminished the increased vasoconstrictor responses and endothelial dysfunction induced by AngII infusion. Hypertensive animals showed increased mPGES-1 expression and PGE2 production in vascular tissue, normalized by celecoxib. Celecoxib treatment also decreased AngII-induced macrophage infiltration and TNF-α expression. Macrophage conditioned media (MCM) increased COX-2 and collagen type I expression in vascular smooth muscle cells; the latter was reduced by celecoxib treatment.

Conclusions And Implications: COX-2 and EP1 receptors participate in the increased extracellular matrix deposition and vascular stiffness, the impaired vascular function and inflammation in hypertension. Targeting PGE2 receptors might have benefits in hypertension-associated vascular damage.