Long-chain polyunsaturated fatty acids interact with nitric oxide, superoxide anion, and transforming growth factor-β to prevent human essential hypertension

Abstract

Patients with uncontrolled essential hypertension have elevated concentrations of superoxide anion (O2-), hydrogen peroxide (H2O2), lipid peroxides, endothelin, and transforming growth factor- (TGF-) with a simultaneous decrease in endothelial nitric oxide (eNO), superoxide dismutase (SOD), vitamin E, and long-chain polyunsaturated fatty acids (LCPUFAs). Physiological concentrations of angiotensin II activate NAD(P)H oxidase and trigger free radical generation (especially that of O2-). Normally, angiotensin II-induced oxidative stress is abrogated by adequate production and release of eNO, which quenches O2- to restore normotension. Angiotensin II also stimulates the production of endothelin and TGF-. TGF- enhances NO generation, which in turn suppresses TGF- production. Thus, NO has a regulatory role on TGF- production and is also a physiological antagonist of endothelin. Antihypertensive drugs suppress the production of O2- and TGF- and enhance eNO synthesis to bring about their beneficial actions. LCPUFAs suppress angiotensin-converting enzyme (ACE) activity, reduce angiotensin II formation, enhance eNO generation, and suppress TGF- expression. Perinatal supplementation of LCPUFAs decreases insulin resistance and prevents the development of hypertension in adult life, whereas deficiency of LCPUFAs in the perinatal period results in raised blood pressure later in life. Patients with essential hypertension have low concentrations of various LCPUFAs in their plasma phospholipid fraction. Based on this, it is proposed that LCPUFAs serve as endogenous regulators of ACE activity, O2-, eNO generation, and TGF- expression. Further, LCPUFAs have actions similar to statins, inhibit (especially -3 fatty acids) cyclooxygenase activity and suppress the synthesis of proinflammatory cytokines, and activate the parasympathetic nervous system, all actions that reduce the risk of major vascular events. Hence, it is proposed that availability of adequate amounts of LCPUFAs during the critical periods of growth prevents the development of hypertension in adulthood.