Essential hypertension and oxidative stress: New insights

Abstract

Essential hypertension is a highly prevalent pathological condition that is considered as one of the most relevant cardiovascular risk factors and is an important cause of morbidity and mortality around the world. Despite the fact that mechanisms underlying hypertension are not yet fully elucidated, a large amount of evidence shows that oxidative stress plays a central role in its pathophysiology. Oxidative stress can be defined as an imbalance between oxidant agents, such as superoxide anion, and antioxidant molecules, and leads to a decrease in nitric oxide bioavailability, which is the main factor responsible for maintaining the vascular tone. Several vasoconstrictor peptides, such as angiotensin II, endothelin-1 and urotensin II, act through their receptors to stimulate the production of reactive oxygen species, by activating enzymes like NADPH oxidase and xanthine oxidase. The knowledge of the mechanism described above has allowed generating new therapeutic strategies against hypertension based on the use of antioxidants agents, including vitamin C and E, N-Acetylcysteine, polyphenols and selenium, among others. These substances have different therapeutic targets, but all represent antioxidant reinforcement. Several clinical trials using antioxidants have been made. The aim of the present review is to provide new insights about the key role of oxidative stress in the pathophysiology of essential hypertension and new clinical attempts to demonstrate the usefulness of antioxidant therapy in the treatment of hypertension.

Fetal undernutrition is associated with perinatal sex-dependent alterations in oxidative status

“…Hypertension is associated with cardiovascular fibrosis, remodeling and endothelial dysfunction, alterations where oxidative stress plays a key role [37][38][39]. Similar cardiovascular alterations have been found in adult IUGR rats [40][41][42] and therefore oxidative stress has been proposed as a possible mechanism implicated in fetal programming of hypertension [7,43].…”

Longitudinal association between selenium levels and hypertension in a rural elderly Chinese cohort

“…While the biological mechanism underlying a positive association between selenium and blood pressure measure is not yet fully understood, selenium's effect on oxidative stress has been investigated in animal studies. As a key component of many antioxidant enzymes, such as glutathione peroxidase (GPx) selenium plays an important role in oxidative stress [27], which is recognized as one of the fundamental mechanisms underlying hypertension [2]. An experimental study had observed that selenium at low doses can provide significant protection of the human coronary artery endothelium against damage by oxidative stress [28].…”

“…Studies have shown that oxidative stress is one of the fundamental mechanisms underlying hypertension [2]. Antioxidants inhibit oxidation reactions, thereby reducing the number of free radicals produced and the amount of damage they can cause.…”

Hypertension as an autoimmune and inflammatory disease

“…30,31 In addition, population-based observational studies demonstrated an inverse correlation between plasma antioxidant levels and blood pressure levels. 32 An increased local ROS concentration in the kidney may have a pivotal role in the generation of hypertension. ROS-induced vascular remodeling impairs autoregulation and may lead to distal tubulointerstitial ischemia.…”