Reporting at the 6th International Congress of Neuroendocrinology (ICN 2006) in Pittsburgh, Polish researchers who studied women aged 20 to 102 suggest a small protein derived from fat tissue may be an important determinant of longevity. Other research indicates boosting growth hormone may allow the elderly to live independently longer. ICN 2006 takes place June 19-22 at the David L. Lawrence Convention Center in downtown Pittsburgh.
Summaries of these studies' findings follow:
Can stimulating growth hormone delay the physiological effects of aging?
Boosting production of growth hormone may extend the time that elderly men and women can live independently, suggests a study of an investigational oral medication led by George R. Merriam, M.D., professor of medicine at the University of Washington/VA Puget Sound Health Care System, and colleagues.
Aging is characterized by a progressive decline in muscle mass, strength and exercise capacity, often leading to frailty and the inability for living independently. Since growth hormone (GH) secretion also declines with age and many age-related changes resemble those seen in GH deficiency, the researchers are investigating the potential physical and endocrine effects of stimulating GH in older adults.
In this controlled trial involving 395 men and women aged 65 to 84 with mild limitations in their physical functioning, participants received either placebo or various oral doses of the growth hormone stimulator (GHS) capromorelin, an investigational medication discovered and developed by Pfizer Global Research and Development. Compared to placebo, GHS at any dose prompted an acute GH peak and an increase in overnight GH secretion - increases that were sustained throughout a 12-month treatment period. The GHS treatment also was associated with a 1.4 Kg increase in lean body (muscle) mass and an improvement in tandem (heel-to-toe) walking at 6 months and in stair climbing at 12 months.
Hormone may hold clue to longevity
A protein derived from fat tissue may be an important determinant of longevity, suggests a study of 133 women, including 25 aged 100 to 102, whom researchers found had notably higher levels of adiponectin circulating in their blood. Adiponectin is a peptide that has anti-inflammatory properties, helps keep vessels clear of fatty deposits and plays an important role in metabolism, particularly of lipids and glucose. Insufficient levels of adiponectin are thought to contribute to obesity, insulin resistance, diabetes or the formation of lipid deposits in the arteries, collectively known as symptoms of metabolic syndrome.
The study, which was conducted by Agnieszka Baranowska-Bik, M.D., and colleagues from the Medical Centre of Postgraduate Education, Warsaw, Poland, looked at blood plasma concentrations of adiponectin in four groups of women: the 25 centenarians, 26 women aged 64 to 67, 45 between the ages of 20 and 43, and 37 obese women aged 26 to 54. Compared to the other groups, the oldest old had significantly higher concentrations of adiponectin as well as much lower levels of both leptin and insulin. Moreover, the oldest-old women scored better with respect to insulin resistance and total cholesterol. Compared to the obese women, who, as expected, had more evidence of metabolic disturbances, the centenarians had significantly fewer signs of hypertension and other symptoms characteristic of metabolic syndrome. Dr. Baranowska-Bik stops short of calling adiponectin the fountain of youth, but the results of this study, she argues, provide evidence that adiponectin may play an important role in longevity.
Held in a different part of the world every four years under the auspices of the International Neuroendocrine Federation, this year's congress - Bridging Neuroscience and Endocrinology - is being sponsored by the American Neuroendocrine Society and the University of Pittsburgh School of Medicine. The first full day of the program, June 20, is being held in conjunction with the 10th Annual Meeting of the Society for Behavioral Neuroendocrinology.
Formerly the International Society of Neuroendocrinology, the International Neuroendocrine Federation consists of six member societies and seven regional groups, representing all parts of the world. The federation's president is John A. Russell, MBChB, Ph.D., chair of neuroendocrinology, University of Edinburgh. The chair of the ICN 2006 scientific program is Iain J. Clarke, Ph.D., professorial fellow in the department of physiology at Monash University in Australia. Tony Plant, Ph.D., professor of cell biology and physiology and director of the Center for Research in Reproductive Physiology, University of Pittsburgh School of Medicine, is chair of the local organizing committee.
NOTE TO EDITORS:
The researchers will discuss their work during a briefing, "What's New About Getting Old," Wednesday, June 21 at 11:30 a.m., that will be moderated by Robert Gibbs, Ph.D., professor, pharmaceutical sciences, University of Pittsburgh School of Pharmacy. All briefings take place in rooms 306-307 of the David L. Lawrence Convention Center, downtown Pittsburgh. Reporters may participate via telephone conference call by dialing 800-860-2442 (from within the U.S.) or 866-519-5086 (from Canada). From other countries, call 001-412-858-4600. To be connected to the briefing you must reference ICN 2006. More information about the meeting and the schedule of briefings are available at http://newsbureau.