Abstract 202: Activation of Cyp4a12-20-HETE Synthase Increases Blood Pressure and Promotes Vascular Hypertrophy and Cardiac Dysfunction

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Abstract

20-Hydroxyeicosatetraenoic acid (20-HETE) is a microcirculatory cytochrome P450-derived eicosanoid shown to increase smooth muscle contractions and proliferation, stimulate endothelial dysfunction and activation, and promotes hypertension. We developed a mouse model (Cyp4a12tg) in which the expression of Cyp4a12, the sole 20-HETE synthase in mouse, is under the control of the doxycycline (DOX) promoter. Administration of DOX to Cyp4a12tg mice increased blood pressure (131±3 vs 100±2 mmHg, p<0.05), which was prevented by co-treatment with the 20-HETE antagonist, 20-HEDGE (96±3 mmHg, p<0.05). Media-to-lumen ratio and medial cross sectional area of renal microvessels from DOX-treated Cyp4a12tg mice significantly increased compared to untreated (M/L, 0.15±0.01 vs 0.07±0.01; mCSAx103 10.8±0.92 vs. 6.4±0.48 mm2); these increases were abolished by co-treatment with 20-HEDGE. Cardiac output and heart rate were unchanged, whereas %EF and %FS were reduced and LV volume and diameter at systole increased in DOX-treated Cyp4a12tg. Total peripheral resistance (TPR) was significantly increased in DOX-treated Cyp4a12tg mice (8.00±0.39 vs 6.77±0.36 mmHg/ml/min, p<0.05); co-treatment with 20-HEDGE decreased (p<0.0%) DOX-induced TPR in Cyp4a12tg mice (7.45±0.22 mmHg/ml/min). These results indicate that activation of Cyp4a12-20-HETE synthase causes hypertension, microvascular remodeling, and cardiac dysfunction. The results also suggest that 20-HETE promotes hypertension by increasing TPR. However, the mechanisms underlying Cyp4a12-20-HETE-driven microvascular remodeling and cardiac dysfunction are yet to be explored.

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