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This Article Full Text Full Text (PDF) All Versions of this Article: 294/5/R1453    most recent 00035.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Yukawa, M. Articles by Wolden-Hanson, T. PubMed PubMed Citation Articles by Yukawa, M. Articles by Wolden-Hanson, T.

APPETITE, OBESITY, DIGESTION, AND METABOLISM

Peripheral ghrelin treatment stabilizes body weights of senescent male Brown Norway rats at baseline and after surgery

¹Geriatric Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System and Divisions of ²Gerontology and Geriatric Medicine and ³Metabolism, Endocrinology, and Nutrition, University of Washington School of Medicine, Seattle, Washington

Submitted 17 January 2008 ; accepted in final form 3 March 2008

Unintentional weight loss may occur spontaneously in older humans and animals. Further weight losses after surgery or illness in the older patients result in increased morbidity, mortality, and hospital readmission rate. A growing body of work has shown increased appetite and weight gain in response to administration of ghrelin, the "hunger hormone." We conducted two studies in senescent male Brown Norway rats to assess the ability of peripheral administration of ghrelin to increase body weight and food intake. One study assessed the effect of 2 wk of daily subcutaneous ghrelin administration (1 mg·kg^–1·day^–1) to senescent rats in a baseline condition; a second study used the same administration protocol in an interventional experiment with aged rats subjected to a surgery with 10–15% blood loss as a model of elective surgery. In both studies, animals receiving ghrelin maintained their body weights, whereas control animals lost weight. Body weight stability was achieved in ghrelin-treated animals despite a lack of increase in daily or cumulative food intake in both experiments. Hormone and proinflammatory cytokine levels were measured before surgery and after 14 days of treatment. Ghrelin treatment appeared to blunt declining ghrelin levels and also to blunt cytokine increases seen in the surgical control group. The ability of peripheral ghrelin treatment to maintain body weights of senescent rats without concomitant increases in food intake may be due to its known ability to decrease sympathetic activity and metabolic rate, perhaps by limiting cytokine-driven inflammation.

energy balance; anorexia of aging; postoperative; cytokine