Why Belly Fat Isn't All Bad

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Why Belly Fat Isn't All Bad

http://www.sciencedaily.com/releases/2012/06/120606193448.htm

ScienceDaily (June 6, 2012) - A fatty membrane in the belly called the

omentum has until recently been considered somewhat like the appendix -- it

didn't seem to serve much purpose.

But Loyola University Chicago Stritch School of Medicine researchers have

found that the omentum appears to play an important role in regulating the

immune system. The finding could lead to new drugs for organ transplant

patients and patients with auto-immune diseases such as lupus and Crohn's

disease.

" We now have evidence that the omentum is not just fat sitting in the

belly, " said Makio Iwashima, PhD, corresponding author of a study published

in the June 6 issue of PLoS ONE. Iwashima is an associate professor in the

Department of Microbiology and Immunology.

The omentum is a membrane that lines the abdominal cavity and covers most

abdominal organs. It is a repository for fat tissue.

A research team headed by Iwashima and Love, MD, a world renowned

lung transplant surgeon, examined the effect that mouse omentum cells had on

T lymphocyte cells from a mouse. T cells are the immune system's first line

of defense against infection. They identify, attack and destroy bacteria,

viruses and other infectious agents.

Normally, T cells multiply in response to an infectious agent, such as an

antibody. But when researchers put omentum cells in with activated T cells

that had been exposed to antibodies, the T cells did not multiply as they

normally would, but instead died. The omentum cells had this effect only on

T cells that had been activated. Omentum cells did not have any effect on

inactive T cells.

It appears that omentum cells secrete a substance that tamps down the immune

system. This discovery could lead to new drugs that would suppress the

immune system with fewer side effects than those caused by

immune-suppressing drugs now in use. Such drugs could be used, for example,

to suppress the immune system in a patient who has received a lung

transplant.

In addition to modulating the immune system, the omentum also appears to

play a critical role in regenerating damaged tissues, Iwashima said. The

omentum contains mesenchymal stem cells that migrate to the site of an

injury and help regenerate tissue. Mesenchymal stem cells are cells that

have the ability to develop into various types of specialized cells.

In this study, researchers showed that, in tissue-culture flasks, omentum

cells can differentiate into lung-type cells as well as bone cells. Iwashima

believes the omentum may be the organ specified for tissue healing and

regeneration.

The study was supported by the National Institutes of Health and Van Kampen

Cardiovascular Research Fund.

Other co-authors, all at Loyola, are Shivanee Shah (first author),

Lowery, Rudolf K. Braun, , Nick Huang, Medina,

Periannan Sethupathi, Yoichi Seki, Mariko Takami, Byrne and

Wigfield.