Is there a role for the ob gene product leptin in essential hypertension?

Abstract

In this study we wanted to evaluate the relationship between the ob gene product leptin and blood pressure, as well as plasma renin activity and plasma aldosterone levels. We studied 139 subjects with a mean ؎ ؎ SD age of 50 ؎ ؎ 14 years and a body mass index of 26.5 ؎ ؎ 5.3 kg/m 2 ; 110 subjects had essential hypertension and 29 were healthy nonhypertensive controls. Blood pressure was measured in resting conditions in the morning and blood was drawn for the determination of the plasma renin activity, aldosterone, and leptin levels. The mean blood pressure of the population was 155/97 mm Hg. The relationship between these parameters was studied by univariate regression analysis according to gender and, whenever indicated, adjusted for age and body mass. The mean ؎ ؎ SEM plasma leptin level in the whole population was 9.5 ؎ ؎ 0.6 ng/mL (range, 1.1-43.3). Subjects with stage I hypertension had significantly higher plasma leptin levels than normotensive subjects. Systolic blood pressure correlated with the plasma leptin levels and the leptin levels adjusted for body weight in women (r ‫؍‬ ‫؍‬ 0.422, P < < .01) and nonhypertensive men (r ‫؍‬ ‫؍‬ 0.644, P ‫؍‬ ‫؍‬ .03) only.Plasma renin activity (r ‫؍‬ ‫؍‬ 0.329, P ‫؍‬ ‫؍‬ .03) and aldosterone levels (r ‫؍‬ ‫؍‬ 0.342, P ‫؍‬ ‫؍‬ .026) correlated with the leptin concentration. A significant relationship between the peripheral expression of the ob gene product leptin and systolic blood pressure was found in women and nonhypertensive men. In view of the multiple functions of leptin a causal relationship is postulated and potential mechanisms may involve modulatory effects of leptin on neuropeptide Y, angiotensinogen gene expression, the modulation of the autonomous nervous system, or effects on the pituitary adrenal axis. Direct relationships between both plasma renin activity and aldosterone levels and leptin support the potential importance of the relationship between leptin and blood pressure. Our observation may be of future importance for the understanding of the link between the increase in blood pressure and increasing body weight.

A Positive Association between Leptin and Blood Pressure of Normal Range in Japanese Men

“…However, leptin has also been reported to have depressor effects; that is, leptin was shown to function as a diuretic/ natriuretic factor (39) and to induce a release of nitric oxide that opposes the pressor action (25). Although many epidemiologic researchers had studied the association of leptin with blood pressure and the sympathetic nervous system, these results were not consistent (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(40)(41)(42)(43)(44)(45). Our results may partly explain this diversity of findings.…”

Obesity and Eye Diseases

“…19, 178 Finally, as discussed in previous sections, obesity may increase oxidative stress because of its associated hyperleptinemia. 14, 31, 59, 78, 79, 103, 149, 219 High levels of plasma leptin have been found to relate to both hypertensive 4,172,194,203 and diabetic retinopathy. 57, 203 Detailed pathophysiological pathways leading to hypertensive retinopathy has been described elsewhere, 215 but leptin has been postulated to worsen hypertension by activation of the sympathetic nervous system, accelerating the development of hypertensive retinopathy.…”

Hypertension and Obesity

“…teracts its pressor effects (Hirose et al, 1998;Suter et al, 1998;Frubeck, 1999;Lembo et al, 2000;Kuo et al, 2001). An alternative explanation is that leptin's sympathetic effect on peripheral vasoconstriction is probably not potent enough to produce significant blood pressure elevation, while the main leptin pressor effect is via the SNS, causing avid renal salt retention and hence hypertension.…”