Navigation Links
U of I study shows benefits of hormone found in fat tissue
Date:2/26/2009

It's called the obesity paradox. Although obese people are more apt to suffer from inflammatory diseases, such as diabetes, heart disease, and stroke, they are also more likely to survive a major attack caused by one of those conditions.

University of Illinois scientists Gregory Freund and Christina Sherry shed light on the reasons for this phenomenon in a study in this month's issue of Endocrinology.

"Fat is a very complex and active tissueit has important functions beyond providing energy and insulating us from the cold," said Freund, a professor in the U of I College of Medicine's Department of Pathology and a faculty member in the U of I Division of Nutritional Sciences.

"We now know that leptin, a hormone secreted by fat tissue, plays a key role in regulating the immune system. When we exposed mice to hypoxia (simulating an event, such as a heart attack, in which a part of the body is deprived of oxygen), leptin triggered the immune system to increase production of an anti-inflammatory molecule, interleukin-1 receptor antagonist (IL-1RA)," he said.

"And, when we gave non-obese mice leptin injections, they recovered three times faster. Leptin did not hasten recovery though in IL-1RA knockout mice," Sherry said. That earlier work was published in a recent issue of Brain, Behavior, and Immunity.

In the Endocrinology study, one group of mice was fed a high-fat diet for 12 weeks (Sherry described this group as being in a mildly obese, pre-diabetic state), while another group was fed a normal diet. The obese mice recovered from acute hypoxia five times faster than the mice fed normal diets.

In a second experiment, Freund and Sherry examined macrophages (or immune cells) that were resident in peritoneal fat tissue from both groups of mice. In mice fed the high-fat diet, there was a very significant increase in IL-1RA as compared to mice fed the normal diet (330 pg vs.15 pg).

"Our hypothesis is that the macrophages from animals fed the high-fat diet are making more IL-1RA because they're 'living' in an environment of significantly increased leptin. Obesity can be considered a state of hyperleptinemia," said Sherry.

The scientists then isolated the stromal vascular fraction of the fat tissuewhich contains the macrophagesfrom three obese mice and injected it into the peritoneal cavity of a normal mouse. "Within 3 hours we saw an 836 percent increase in the IL-1RA serum level of the normal mouse and an accelerated recovery from hypoxia," Sherry said.

To confirm that IL-1RA was implicated in this accelerated recovery, normal mice were given injections of IL-1RA, and their recovery matched that of mice fed the high-fat diet.

Finally, Freund and Sherry injected IL-1RA antiserum into the obese animals an hour before exposing them to hypoxia.

"We expected the antibodies to bind all the IL-1RA so it couldn't affect recovery," she said. "And, sure enough, these animals didn't recover until 6 hours after the hypoxic event, basically the same pattern we saw with non-obese animals."

"So we were able to prove through several different mechanisms that in cases of obesity, there's a significant increase in the anti-inflammatory molecule IL-1RA, which helps animals recover from a traumatic loss of oxygen. The obese mice recovered faster because of the leptin-induced increase in IL-1RA," said Sherry.

Sherry repeated that obesity is a predisposing factor in many inflammatory conditions and encouraged people who are at a healthy weight to maintain that weight.

"However, obese persons do have about six times more circulating IL-1RA, which again is the anti-inflammatory molecule that aids recovery in oxygen-starved parts of the body," she noted.

"Once a health problem is established, there are certain conditionscongestive heart failure, rheumatoid arthritis, and other diseases that involve the utilization of oxygenin which obese persons have been shown to have a better prognosis. And there is a legitimate discussion among physicians about how such patients should deal with their excess weight," said Freund.


'/>"/>

Contact: Phyllis Picklesimer
p-pickle@uiuc.edu
217-244-2827
University of Illinois at Urbana-Champaign
Source:Eurekalert

Related medicine news :

1. Federally-Funded Study Says Focus Should Be on Total Calories, Not Particular Foods
2. New Partnership for a Drug-Free America 20th Annual Study Shows Progress in Teens Recognizing Dangers of OTC Cough Medicine Abuse
3. The Catalyst Foundations Groundbreaking ACE Study-Based Services Bring Transformational Change to Healthcare
4. Want to Lose Weight? Just Eat Less, Diet Study Suggests
5. Study Pinpoints New Gene for Cystic Fibrosis
6. Study analyzes 2006 California heat waves substantial effect on morbidity
7. Study Shows Simple Measures May Help Prevent Sudden Death Event in Young Athletes
8. Million women study shows even moderate alcohol consumption associated with increased cancer risk
9. Cardiologists initiate STILETTO study to investigate treatment options for women with chest pain
10. National Lessons from State Health Reform: The Massachusetts Case Study
11. PSA Tests Not Race-Specific, Study Finds
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/24/2017)... ... April 24, 2017 , ... Donna Parker, L. Ac. reads ... not found any of them to be very practical. She wanted to write a ... make changes in their health. It prompted her in writing “ A Clear Path ...
(Date:4/24/2017)... ... April 24, 2017 , ... “The Saint with Trin, ... Trin, and Omega Station” is the creation of published author, Chris Jackson. Chris ... where he works in the Dallas Independent School District teaching English. He is heavily ...
(Date:4/24/2017)... , ... April 24, 2017 , ... ... development of next generation neuro-thrombectomy systems for the treatment of Acute Ischemic Stroke ... its ANCD BRAIN device as the product advances towards regulatory and clinical phases. ...
(Date:4/22/2017)... , ... April 22, 2017 , ... Ecommerce sales have ... States estimated to be $394.9 billion. The consequences of rapid innovation and growth ... the limits of technology, it is every business and individual’s job to give something ...
(Date:4/22/2017)... ... 2017 , ... The San Juan Capistrano summer camp team at the Boys and ... for summer camps to provide physical activities for all campers. To read the report, ... , With an increase in specialty camps that focus on what the report terms as ...
Breaking Medicine News(10 mins):
(Date:4/20/2017)... 20, 2017  AbbVie (NYSE: ABBV), a global ... of chronic hepatitis C virus (HCV) infected patients ... and compensated cirrhosis (Child-Pugh A) achieved sustained virologic ... with its investigational, pan-genotypic regimen of glecaprevir/pibrentasvir (G/P). ... following 12 weeks of G/P treatment without ribavirin. ...
(Date:4/20/2017)... DUBLIN , April 20, 2017 ... "Latin America Pharmaceutical Contract Manufacturing Services Market Analysis By Service ... And Segment Forecasts, 2014 - 2025" report to their ... The Latin ... USD 21.0 billion by 2025 Low drug registration ...
(Date:4/19/2017)... 19, 2017  IRIDEX Corporation (Nasdaq: IRIX ... for the first quarter 2017 after the close of ... team will host a corresponding conference call beginning at ... Investors interested in listening to the conference call may ... or (703) 326-3030 for international callers, using conference ID: ...
Breaking Medicine Technology: