α-Lipoic Acid Reduces Hypertension and Increases Baroreflex Sensitivity in Renovascular Hypertensive Rats

Abstract

Renovascular hypertension has robust effects on control of blood pressure, including an impairment in baroreflex mechanisms, which involves oxidative stress. Although α-lipoic acid (LA) has been described as a potent antioxidant, its effect on renovascular hypertension and baroreflex sensitivity (BRS) has not been investigated. In the present study we analyzed the effects caused by chronic treatment with LA on blood pressure, heart rate and baroreflex sensitivity (sympathetic and parasympathetic components) in renovascular hypertensive rats. Male Wistar rats underwent 2-Kidney-1-Clip (2K1C) or sham surgery and were maintained untouched for four weeks to develop hypertension. Four weeks post-surgery, rats were treated with LA (60 mg/kg) or saline for 14 days orally. On the 15th day mean arterial pressure (MAP) and heart rate (HR) were recorded. In addition, baroreflex sensitivity test using phenylephrine (8 µg/kg, i.v.) and sodium nitroprusside (25 µg/kg, i.v.) was performed. Chronic treatment with LA decreased blood pressure in hypertensive animals; however, no significant changes in baseline HR were observed. Regarding baroreflex, LA treatment increased the sensitivity of both the sympathetic and parasympathetic components. All parameters studied were not affected by treatment with LA in normotensive animals. Our data suggest that chronic treatment with LA promotes antihypertensive effect and improves baroreflex sensitivity in rats with renovascular hypertension.

Vascular Dysfunction and Chronic Obstructive Pulmonary Disease

“…Therefore, based upon the current findings, it seems reasonable to propose that, in an attempt to improve vascular health and reduce cardiovascular disease risk in patients with COPD, an increase in antioxidant capacity could be targeted, perhaps by exogenous antioxidant supplementation or endogenously through exercise training 63 , thereby reducing free radicals and improving endothelial function. While the success of the clinical trials using antioxidants as an intervention in CVD have been mixed 64–68 , it is important to note that most trials have utilized a single antioxidant, and not a cocktail containing both water and fat soluble vitamins as in the current study. The antioxidant-induced improvement in vascular function, assessed by FMD and PWV, observed in the current study is suggestive of a reduction in the risk of cardiovascular disease associated with COPD, however, a randomized controlled trial with long-term supplementation is needed to confirm this hypothesis.…”

Coconut oil supplementation and physical exercise improves baroreflex sensitivity and oxidative stress in hypertensive rats

“…Several reports from our laboratory have demonstrated that antioxidants added in the diet, such as rutine (Mendes-Junior et al 2013), lipoic acid (Queiroz et al 2012) and quercetin (Monteiro et al 2012), reduce ROS levels and restore baroreflex sensitivity in hypertensive rats. Nowadays, coconut oil has been used as dietary supplement because of its many benefits, including but not limited to weight loss (Assunção et al 2009), anti-inflammatory (Intahphuak et al 2010;Vysakh et al 2014), antibacterial (Nevin and Rajamohan, 2004), and antioxidant activity (Vysakh et al 2014).…”

Angiotensin-II-derived reactive oxygen species on baroreflex sensitivity during hypertension: new perspectives

“…Previous reports have suggested that baroreflex sensitivity (BRS) is reduced during hypertension and the mechanisms underlying its reduction involves ROS (Braga, 2010; Botelho-Ono et al, 2011; Guimarães et al, 2012; Queiroz et al, 2012). …”

“…Among these, we can highlight the use of antioxidant therapy, such as ROS scavengers and vitamins, SOD mimetics or NAD(P)H oxidase inhibitors that has experimentally shown to attenuate or prevent the development of hypertension (Chen et al, 2001; Landmesser et al, 2003; Costa et al, 2009; Queiroz et al, 2012). …”