Context: Leptin has nitric oxide (NO)-dependent vasodilator actions, but hyperleptinemia is an independent risk factor for cardiovascular disease. Objective: The objective of the study was to investigate whether, in the human circulation, properties of leptin to release NO are opposed by stimulation of vasculotoxic substances, such as endothelin (ET)-1, and whether this mechanism might contribute to vascular damage in hyperleptinemic states like obesity. Methods: Forearm blood flow responses (plethysmography) to ET receptor antagonism (BQ-123, 10 nmol/min) and NO synthase inhibition [N-monomethyl L-arginine (L-NMMA), 4 μmol/min] were assessed before and after intraarterial administration of leptin (2 μg/min) in lean controls (n = 8) and patients with obesity-related metabolic syndrome (MetS; n = 8). Results: Baseline plasma leptin was higher in patients than in controls (P < .001). Before infusion of leptin, the vasodilator response to BQ-123 was greater in patients than in controls (P < .001), whereas infusion of L-NMMA induced higher vasoconstriction in controls than in patients (P = .04). In lean subjects, hyperleptinemia resulted in increased vasodilator response to ET receptor antagonism (P < .001 vs before) and enhanced vasoconstrictor effect of L-NMMA during ET receptor blockade (P = .015 vs before). In patients with the MetS, by contrast, vascular responses to both BQ-123 and L-NMMA were not modified by exogenous leptin (both P > .05 vs before). Conclusions: These findings indicate that, under physiological conditions, leptin stimulates both ET-1 and NO activity in the human circulation. This effect is absent in hyperleptinemic patients with the MetS who are unresponsive to additional leptin. In these patients, therefore, hyperleptinemia may be a biomarker of vascular dysfunction, rather than a mediator of vascular damage.

Schinzari, F., Tesauro, M., Rovella, V., Di Daniele, N., Mores, N., Veneziani, A., Cardillo, C., Leptin stimulates both endothelin-1 and nitric oxide activity in lean subjects but not in patients with obesity-related metabolic syndrome, <<THE JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM>>, 2013; 98 (3): 1235-1241. [doi:10.1210/jc.2012-3424] [http://hdl.handle.net/10807/42647]

Leptin stimulates both endothelin-1 and nitric oxide activity in lean subjects but not in patients with obesity-related metabolic syndrome

Schinzari, Francesca;Mores, Nadia;Veneziani, Augusto;Cardillo, Carmine
2013

Abstract

Context: Leptin has nitric oxide (NO)-dependent vasodilator actions, but hyperleptinemia is an independent risk factor for cardiovascular disease. Objective: The objective of the study was to investigate whether, in the human circulation, properties of leptin to release NO are opposed by stimulation of vasculotoxic substances, such as endothelin (ET)-1, and whether this mechanism might contribute to vascular damage in hyperleptinemic states like obesity. Methods: Forearm blood flow responses (plethysmography) to ET receptor antagonism (BQ-123, 10 nmol/min) and NO synthase inhibition [N-monomethyl L-arginine (L-NMMA), 4 μmol/min] were assessed before and after intraarterial administration of leptin (2 μg/min) in lean controls (n = 8) and patients with obesity-related metabolic syndrome (MetS; n = 8). Results: Baseline plasma leptin was higher in patients than in controls (P < .001). Before infusion of leptin, the vasodilator response to BQ-123 was greater in patients than in controls (P < .001), whereas infusion of L-NMMA induced higher vasoconstriction in controls than in patients (P = .04). In lean subjects, hyperleptinemia resulted in increased vasodilator response to ET receptor antagonism (P < .001 vs before) and enhanced vasoconstrictor effect of L-NMMA during ET receptor blockade (P = .015 vs before). In patients with the MetS, by contrast, vascular responses to both BQ-123 and L-NMMA were not modified by exogenous leptin (both P > .05 vs before). Conclusions: These findings indicate that, under physiological conditions, leptin stimulates both ET-1 and NO activity in the human circulation. This effect is absent in hyperleptinemic patients with the MetS who are unresponsive to additional leptin. In these patients, therefore, hyperleptinemia may be a biomarker of vascular dysfunction, rather than a mediator of vascular damage.
Inglese
Schinzari, F., Tesauro, M., Rovella, V., Di Daniele, N., Mores, N., Veneziani, A., Cardillo, C., Leptin stimulates both endothelin-1 and nitric oxide activity in lean subjects but not in patients with obesity-related metabolic syndrome, <>, 2013; 98 (3): 1235-1241. [doi:10.1210/jc.2012-3424] [http://hdl.handle.net/10807/42647]
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10807/42647
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