RESUMEN
RATIONALE: αCGRP (α calcitonin gene-related peptide), one of the strongest vasodilators, is cardioprotective in hypertension by reducing the elevated blood pressure. OBJECTIVE: However, we hypothesize that endogenous, physical activity-induced αCGRP has blood pressure-independent cardioprotective effects in chronic hypertension. METHODS AND RESULTS: Chronically hypertensive (one-kidney-one-clip surgery) wild-type and αCGRP-/- sedentary or voluntary wheel running mice were treated with vehicle, αCGRP, or the αCGRP receptor antagonist CGRP8-37. Cardiac function and myocardial phenotype were evaluated echocardiographically and by molecular, cellular, and histological analysis, respectively. Blood pressure was similar among all hypertensive experimental groups. Endogenous αCGRP limited pathological remodeling and heart failure in sedentary, chronically hypertensive wild-type mice. In these mice, voluntary wheel running significantly improved myocardial phenotype and function, which was abolished by CGRP8-37 treatment. In αCGRP-/- mice, αCGRP treatment, in contrast to voluntary wheel running, improved myocardial phenotype and function. Specific inhibition of proliferation and myofibroblast differentiation of primary, murine cardiac fibroblasts by αCGRP suggests involvement of these cells in αCGRP-dependent blunting of pathological cardiac remodeling. CONCLUSIONS: Endogenous, physical activity-induced αCGRP has blood pressure-independent cardioprotective effects and is crucial for maintaining cardiac function in chronic hypertension. Consequently, inhibiting endogenous αCGRP signaling, as currently approved for migraine prophylaxis, could endanger patients with hypertension.
Asunto(s)
Presión Sanguínea/fisiología , Péptido Relacionado con Gen de Calcitonina/sangre , Hipertensión/sangre , Hipertensión/terapia , Condicionamiento Físico Animal/métodos , Condicionamiento Físico Animal/fisiología , Animales , Biomarcadores/sangre , Células Cultivadas , Enfermedad Crónica , Hipertensión/prevención & control , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Resultado del TratamientoRESUMEN
Congenital heart disease should be considered when evaluating calves with chronic respiratory signs, failure to thrive, poor growth, or if a murmur is heard on physical examination. Echocardiography is currently the gold standard for diagnosing congenital heart defects. A wide variety of defects, either alone or in combination with a ventricular septal defect, are possible. A standardized approach using sequential segmental analysis is required to fully appreciate the nature and severity of more complex malformations. The prognosis for survival varies from guarded to poor and depends on the hemodynamic relevance of the defects and the degree of cardiac compensation.