Protective actions of melatonin and growth hormone on the aged cardiovascular system.

Abstract: Epidemiological studies indicate that certain aspects of lifestyle and genetics act as risk factors for a variety of cardiovascular disorders, including coronary disease, hypertension, heart failure and stroke. Aging, however, appears to be the major contributor for morbid-ity and mortality of the impaired cardiovascular system. Growth hormone (GH) and melatonin seem to prevent cardiac aging, as they contribute to the recovery of several physiological parameters affected by age. These hormones exhibit antioxidant properties and decrease oxidative stress and apoptosis. This paper summarizes a set of stud-ies related to the potential role that therapy with GH and melatonin may play in the protection of the altered car-diac function due to aging, with a focus on experiments performed in our laboratory using the senescence-accel-erated mouse as an aging model. In general, we observed significantly increased inflammation, oxidative stress and apoptosis markers in hearts from senescence-accelerated prone 10 month-old animals compared to 2-month-old controls, while anti-inflammatory and antiapoptotic mark-ers (Bcl-2) as well as endothelial nitric oxide synthase were decreased. Senescence-accelerated resistant animals showed no significant changes with age. GH or melatonin treatment prevented the age-dependent cardiac altera-tions observed in the senescence-accelerated prone group. Combined administration of GH plus melatonin reduced the age-related changes in senescence-accelerated prone hearts in an additive fashion that was different to that dis-played when administered alone. GH and melatonin may be potential agents for counteracting oxidative stress, apo-ptosis and inflammation in the aging heart. Keywords: agin g; cardiovascular disease; growth hormone; melatonin; senescence-accelerated mouse SAM). (