How we can stop stress from making us obese

Contact: Dr. Branwen Morgan
b.morgan@garvan.org.au
61-043-407-1326
Research Australia

Professor Herbert Herzog, Director of the Neuroscience Research Program at the Garvan Institute of Medical Research, together with scientists from the US and Slovakia, have shown that neuropeptide Y (NPY), a molecule the body releases when stressed, can ‘unlock’ Y2 receptors in the body’s fat cells, stimulating the cells to grow in size and number. By blocking those receptors, it may be possible to prevent fat growth, or make fat cells die.

“We have known for over a decade that there is a connection between chronic stress and obesity,” said Professor Herzog. “We also know that NPY plays a major role in other chronic stress-induced conditions, such as susceptibility to infection. Now we have identified the exact pathway, or chain of molecular events, that links chronic stress with obesity.”

“There is not much we can do about the increased levels of NPY caused by stress, but we can do something about the damage it causes. If we can interfere before it causes fat to amass, it could have a major impact on cardiovascular disease, diabetes, and cancer (which all have links with obesity).”

“Basically, when we have a stress reaction, NPY levels rise in our bodies, causing our heart rate and blood pressure to go up, among other things. Stress reactions are normal, unavoidable, and generally serve a useful purpose in life. It’s when stress is chronic that its effects become damaging.”

Scientists at Georgetown University (Washington D.C), part of this collaborative study, have found a direct connection between stress, a high calorie diet and unexpectedly high weight gain. Stressed and unstressed mice were fed normal diets and high calorie (high fat and high sugar, or so called ‘comfort food’) diets. The mice on normal diets did not become obese. However, stressed mice on high calorie diets gained twice as much fat as unstressed mice on the same diet. The novel and unexpected finding was that when stressed and non-stressed animals ate the same high calorie foods, the stressed animals utilised and stored fat differently.

“Our findings suggest that we may be able to reverse or prevent obesity caused by stress and diet, including the worst kind of obesity; the apple-shaped type, which makes people more susceptible to heart disease and diabetes,” says senior author of the Nature Medicine paper, Professor Zofia Zukowska of Georgetown University. “Using animal models, in which we have either blocked the Y2 receptor, or selectively removed the gene from the abdominal fat cells, we have shown that stressed mice on high calorie diets do not become obese. “Even more surprisingly, in addition to having flatter bellies, adverse metabolic changes linked to stress and diet, which include glucose intolerance and fatty liver, became markedly reduced. We do not know yet exactly how that happens, but the effect was remarkable,” she said.

Professor Herzog believes that these research findings will have a profound effect on the way society will deal with the obesity epidemic. “There are millions of people around the world who have lived with high levels of stress for so long their bodies think it’s ‘normal’. If these people also eat a high fat and high sugar diet, which is what many do as a way to reduce their stress, they will become obese.”

“Until now, the pharmaceutical industry has focused on appetite suppressants with only moderate success. Our hope is that in the near future pharmaceutical companies, using the results of our research, will develop antagonists against the Y2 receptor that will bring about a reduction in fat cells.”

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Notes to editors:

Stress-activated adipogenic pathway in fat tissue exaggerates diet-induced obesity and metabolic syndrome.
Kuo, L.E., Kitlinska, J.B., Tilan, J.U., Li, L., Baker, S.B., Johnson, M.D., Lee, E.W., Burnett, M.S., Fricke, S.T., Kvetnansky, R.K., Herzog, H. & Zukowska, Z.
Nature Medicine advance online publication, 1 July 2007

The study was co-funded by the National Institutes of Health, the American Heart Association, and the Slovak Research and Development Agency.

ABOUT GARVAN

The Garvan Institute of Medical Research was founded in 1963. Initially a research department of St Vincent’s Hospital in Sydney, it is now one of Australia’s largest medical research institutions with approximately 400 scientists, students and support staff. Garvan’s main research programs are: Cancer, Diabetes & Obesity, Arthritis & Immunology, Osteoporosis, and Neuroscience. The Garvan’s mission is to make significant contributions to medical science that will change the directions of science and medicine and have major impacts on human health. The outcome of Garvan’s discoveries is the development of better methods of diagnosis, treatment, and ultimately, prevention of disease.

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Place of death shifting for children with complex chronic conditions

Contact: Rachel Salis-Silverman
267-426-6063
JAMA and Archives Journals

It is becoming more common for children with complex chronic conditions to die in their home than in a hospital, although black and Hispanic children with these conditions are less likely to die in their home, according to a study in the June 27 issue of JAMA, a theme issue on chronic diseases of children.

Chris Feudtner, M.D., Ph.D., M.P.H., of Children’s Hospital of Philadelphia, presented the findings of the study at a JAMA media briefing in New York.

Many pediatric palliative care clinicians suggest that the preferred place of death, by the family, of an infant, child, or adolescent with a medically complex chronic condition is the home. Advances in home-based medical technology and changes in attitudes about pediatric palliative care and hospice services may be making this a more viable option, according to background information in the article.

Dr. Feudtner and colleagues conducted a study to determine if the proportion of complex chronic condition-related deaths occurring at home among children and adolescents increased between 1989 and 2003, and to assess if there were any race and ethnicity disparities in the location of death. The researchers analyzed data from the National Center for Health Statistics’ Multiple Cause of Death Files.

Among the 22.1 percent of deaths (198,160 of 896,509 total deaths) attributed to a complex chronic condition between 1989 and 2003, the percentage of deaths occurring at home increased significantly for all age groups (overall, from 10.1 percent in 1989 to 18.2 percent in 2003), but with larger increases for deaths beyond infancy. The odds of death occurring at home increased by 3.8 percent annually.

The percentage of individuals dying at home increased significantly over time for infants (4.9 percent home deaths in 1989 to 7.3 percent in 2003); 1 to 9-year-olds (17.9 percent to 30.7 percent), and 10 to 19-year-olds (18.4 percent to 32.2 percent). During this same period, there was a significant decline in the percentage of deaths occurring in the hospital for each of these three age categories.

The authors suggest that this gradual change in place of death may be occurring because of advances in medical technology in the home setting and broad shifts in attitudes and decision-making processes regarding palliative and end-of-life care in U.S. culture.

The child’s race, ethnicity, and region of home residence were significantly associated with death occurring at home. The odds of dying at home were reduced by 50 percent among black individuals, and reduced by 48 percent among Hispanic individuals, when compared with whites.

Concerning possible reasons for the observed racial and ethnic differences, “ … differential access to health care services or medical technology, divergent cultural attitudes or approaches to palliative and end-of-life care decision making, or differing levels of financial or other support within the patient’s or family’s social network may make dying at home more or less likely.”

“… as efforts to improve understanding of the sources and remedies of racial and ethnic disparities in pediatric end-of-life care are completed, medical and other concerned professionals need to ensure that all patients have access to necessary care and that all dialogue and interactions regarding decisions about care—whether curative, life-extending, or palliative—are built on mutual understanding, trust, and respect,” the authors conclude.

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(JAMA. 2007;297:2725-2732. Available pre-embargo to the media at http://www.jamamedia.org)

Editor’s Note: The conduct of this study was supported in part by grants from the Agency for Healthcare Research and Quality and the National Institute of Nursing Research of the National Institutes of Health. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, etc.

For More Information: Contact the JAMA/Archives Media Relations Department at 312-464-JAMA or email: mediarelations@jama-archives.org.

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US soldiers in Iraq fighting drug-resistant bacteria after injuries

Contact: Amy Jenkins
amy@jenkinspr.com
312-836-0613
University of Chicago Press Journals

ALEXANDRIA, Va. — US soldiers in Iraq do not carry the bacteria responsible for difficult-to-treat wound infections found in military hospitals treating soldiers wounded in Iraq, according to an article to be published electronically on Wednesday, May 16, 2007, in Infection Control and Hospital Epidemiology. The article will appear in the June issue of the journal.

Investigator Matthew E. Griffith, MD, (Brooke Army Medical Center at Fort Sam Houston, San Antonio, Texas) and colleagues found that drug-resistant strains of Acinetobacter calcoaceticus-baumannii complex are not present on the skin of uninjured soldiers in Iraq, as had been expected.

A. calcoaceticus-baumannii complex is an important cause of trauma-associated and hospital-acquired infection throughout the world, and multidrug-resistant strains of the bacteria have been infecting injured soldiers treated in US military hospitals in Iraq.

“We need to know where these infections are coming from,” explains Dr. Griffith. “One of the possibilities was that A. calcoaceticus-baumannii was on the soldiers’ skin before injury and simply traveled to the wound site to cause the infection. However, our research shows that this is not the case.”

Although the consequences of the outbreak A. calcoaceticus-baumannii infection in US military hospitals serving soldiers wounded in Iraq are well described, the source of the outbreak is unknown.

To determine whether A. calcoaceticus-baumannii complex is carried on the skin of healthy US Army soldiers, investigators cultured skin swab specimens from 102 active military soldiers stationed at a base in Iraq. The base is in an environment representative of all Iraqi environments with desert, irrigated farmland and an urban area nearby.

Several previous reports have described skin carriage of Acinetobacter species in healthy people. The carriage rates have been found to vary with climate and geography. These reports may not be generalizable to US Army soldiers in Iraq, which has an extremely dry climate.

“If skin carriage is not the source of A. calcoaceticus-baumannii complex infection, then the other possibility is that the bacteria contaminates the wounds after injury,” explains Dr. Griffith. “This could happen while an injured soldier is awaiting treatment or in the hospital during or after receiving medical care.”

“This observation refutes the concept that the bacterium is acquired prior to injury among soldiers deployed to Iraq,” Dr. Griffith says. “In addition, this observation adds to the ever growing body of evidence implicating nosocomial transmission as the cause of the ongoing military outbreak.”

Because of this and similar research, an increased emphasis on infection control has been put in place in the US military’s combat hospitals.

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Infection Control and Hospital Epidemiology provides original, peer-reviewed scientific articles for anyone involved with an infection control or epidemiology program in a hospital or healthcare facility. Written by infection control practitioners and epidemiologists and guided by an editorial board composed of the nation’s leaders in the field, ICHE provides a critical forum for this vital information.

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