The physiology (Studying the science organisms related to their mechanisms and functions.) regulating appetite and weight control is constantly studied. According to National Center for Health Statistics thirty percent of the United States adults twenty years of age and older (more than 60 million people) are considered obese. In the Journal of the American Medical Association publication, according to a 2006 study, four out of every five Americans men aged 40 – 59 were classified as overweight. Reported by the World Health Organization, about one billion people worldwide are overweight or obese. Developed countries spend two to seven percent of total health care costs on obesity related problems. Body Mass index (BMI) measurement used to determine excess body weight. If the BMI is greater than twenty-five is obese and greater than 40 or more is severe obesity. Obesity contributes a risk factor for a number of diseases including heart, various cancers, Type 2 diabetes, stroke, arthritis, and depression.
Identified in 1999, Ghrelin is a peptide hormone consisting of cells in the stomach, which stimulates hunger (orexigenic) and memory. These cells increase before a meal and decrease after eating in healthy people. In February 19, 2006, online issue of Nature Neuroscience by researchers at Yale and other institutes studied the hormone ghrelin in mice. Their findings revealed the increase amount of hormone ghrelin enters the hipppocampus (Area of the brain: Memory, learning and Emotion) and bind to neurons in the brain, which enhance learning and memory performance. Learning is more effective when ghrelin hormones increase, when the stomach is empty. Conclusion of the study indicated obesity associated to level of ghrelin and increase incidences of memory loss like Alzheimer’s disease. Team leader Tamas L. Horvath (Chairman associate professor of the Section of Comparative Medicine at Yale School of Medicine, and associate professor in the Department of Obstetrics, Gynecology and Reproductive Sciences, and Neurology) said “Based on our observations in animal models, a practical recommendation could be that children may benefit from not overeating at breakfast in order to make the most of their morning hours at school.” Obese children in school have paralleled a decline in learning ability or performance. A study published in May 23, 2002, in The New England Journal of Medicine studied thirteen subjects during a six – month weight reduction program. Their findings had shown that the subjects lost an average of 17 percent of their body weight, and ghrelin output increased by 25 percent. Surgeons performing gastric bypass surgery sewed off a tiny pocket at the top of the stomach. This procedure brings down the production of ghrelin to a barely noticeable level. Apparently, this surgery may cause a person not to feel hungry but cause blood sugar level to decrease, may lead to fainting, if not reminded to eat. Those that have taken anti – fat drugs, half of them experienced an average weight loss between 5 – 10 percent
A vaccine developed by researchers, lead by Dr. Kim Janda of the Scripps Research Institute in La Jolla California, created antibodies against ghrelin hormone, suppressed hunger and weight gain. There study was reported in National Academy of Science publication in week of July 30, 2006. Rats received administered vaccines (Vaccines were labeled Ghr1-2-3. Most effect results occurred when Ghr1 or Ghr3 was administered) gained less weight, while eating the same amount of food, compared to those not given the vaccine (About 0.8 grams a day compared with a weight gain around 1.6 grams). As result of the administered vaccinations, hormone ghrelin in the blood was kept away from the brain, and central nervous system, preventing an increase in fat or developing obesity. However, mice were fed a low fat and low energy diet, may not be comparable to human consumption of high – fat diets (Western diets), when ghrelin vaccine is administered. Researchers are evaluating the appropriate dosage amount to be administered: Given one shot, multiple of shots or administered orally. The Scripps vaccination may begin human trials within two years. Scripps is seeking to find a major pharmaceutical company to help develop their vaccination.
In May 16, 2005, first human trial vaccine designed to trigger antibodies against ghrelin hormone was started by a Swiss biotechnology company, which enrolled 112 obese volunteers, with a mass index of between 30 and 35. Trial study evaluates if blocking ghrelin’s action will lead to weight loss. The study is a combination of phase I / II clinical trial of the vaccine CYT009-GhrQb. The volunteers will receive monthly shots for six months. Previous testing of CYTOO9-GhrQb shown in mice given the vaccine and high – fat diet, reduction of weight gain up to 15 percent. However, according to Dr. Marc Jacobson, a childhood obesity expert at Long Island Jewish Medical Center disagrees with hypothesis that blocking ghrelin hormone will suppress gaining weight, because according to Dr. Jacobson “Ghrelin is one of maybe 10 or 12 different hormones that regulate our weight. Even if a vaccine wipes out this particular hormone’s effect, there might be others that reverse an effect you would get.” Expected published results from Swiss biotechnology company in the second half of 2006
Uncertain future ghrelin vaccination for obese children: Because the stomach pumps ghrelin into the bloodstream and the hormone then travels to the pituitary, where it releases a growth hormone. This is critically important for normal development in children.
Many pharmaceutical companies would be interested researching and manufacturing a synthetic or comparable ghrelin hormone for treating excessive amount of weight loss because of cancer, AIDS, anorexia nervosa or other conditions. Initial studies of ghrelin injections, confirmed that it triggered growth hormones secretion in people, however about 80 percent of volunteers complained of intense hunger. Also, Tamas L. Horvath (previously mentioned in paragraph two) said “that high ghrelin levels or administration of ghrelin – like drugs could also protect against certain forms of dementia, because aging and obesity are associated with a decline in ghrelin levels and an increased incidence of conditions of memory loss like Alzheimer’s disease.
