Oxidative stress and baroreflex sensitivity in healthy subjects and patients with mild-to-moderate hypertension

Abstract

Decreased baroreflex sensitivity (BRS) is a prognostic marker in essential hypertension. Animal experiments suggest that decreased BRS is related to increased oxidative stress. Our study was aimed at testing whether oxidative stress, estimated by isoprostane 15-F 2t -IsoP urinary levels, is correlated to BRS variation in healthy subjects as well as in patients suffering from essential hypertension. Urinary 15-F 2t -IsoP levels and BRS were evaluated in two groups of subjects: healthy volunteers (n ¼ 64) and patients with untreated mild-to-moderate hypertension (n ¼ 33). Data were analysed in 61 and 31 subjects, respectively, BRS analysis being impossible in three and two subjects, respectively. 15-F 2t -IsoP levels were measured using gas chromatography/mass spectrometry. BRS was measured using the sequence method [PS þ /RR þ and PSÀ/RRÀ] and crossspectral analysis (CSP) (MF gain) at rest, lying down. No significant correlation was found between basal urinary 15-F 2t -IsoP levels and BRS (sequence method and CSP) in either healthy controls or hypertensive patients. Our study shows that oxidative stress is not involved in interindividual variations of BRS in healthy subjects and patients suffering from mild-to-moderate hypertension

Baroreflex sensitivity improvement is associated with decreased oxidative stress in trained spontaneously hypertensive rat

“…These correlations indicate that the effect of exercise training on oxidative stress plays an important role in the improvement of BRS. These results agree with other studies, which have also evidenced a relationship between oxidative stress and BRS in healthy individuals and patients with mild to moderate hypertension [36], human chronic heart failure [37], experimental adryamicin-induced heart failure [16], and in ovariectomized rats [14]. However, few studies have shown the influence of different antioxidant interventions such as vitamin C [15,37], vitamin E [38], N-acetylcysteine and melatonin [39] in the association of oxidative stress and BRS.…”

Melatonin in relation to the "strong" and "weak" versions of the free radical theory of aging

“…The "weak" version of the oxidative stress theory postulates that oxidative damage is causative of or associated with age-related diseases. Indeed, there are numerous diseases/conditions that develop in aged individuals that have, at least as part of their basis, free radical damage [5][6][7][8]. These conditions eventually compromise the health of an organism and, ultimately, death follows.…”