CHAMPAIGN, Ill., Mar 3, 2009 (UPI via COMTEX) -- The obese are more apt to
suffer from diabetes, heart disease or stroke, but are more likely to survive an
attack from those conditions, U.S. researchers say.
University of Illinois scientists Gregory Freund and Christina Sherry say the
phenomenon is called the obesity paradox.
"We 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 -- leptin triggered the immune system to increase
production of an anti-inflammatory molecule, interleukin-1 receptor antagonist,"
Freund said in a statement.
The researchers then gave non-obese mice leptin injections and they recovered
three times faster, Sherry said.
In the study, published in Endocrinology, one group of mice was fed a high-fat
diet for 12 weeks, 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 -- immune cells
-- that were resident in fat tissue from both groups of mice. In mice fed the
high-fat diet, there was a very significant increase in interleukin-1 receptor
as compared to mice fed the normal diet.
"Our hypothesis is that the macrophages from animals fed the high-fat diet are
making more interleukin-1 receptor because they're 'living' in an environment of
significantly increased leptin," Sherry said.
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