Scientists discover a 'good' fat that fights diabetes

Researchers uncovered a new class of lipids in humans that is linked to reduced inflammation and improved blood sugar levels in diabetes

(http://www.eurekalert.org/pub_releases/2014-10/si-sda100814.php)

LA JOLLA—Scientists at the Salk Institute and Beth Israel Deaconess Medical Center (BIDMC) in Boston have discovered a new class of molecules—produced in human and mouse fat—that protects against diabetes.

The researchers found that giving this new fat, or lipid, to mice with the equivalent of type 2 diabetes lowered their elevated blood sugar, as detailed October 9 in Cell. The team also found that levels of the new lipids are low in humans with a high risk for diabetes, suggesting that the lipids could potentially be utilized as a therapy for metabolic disorders.

Lipids, like cholesterol, are typically associated with poor health. But in recent years, researchers have discovered that not all lipids are bad for you, such as the much touted omega-3 fatty acids that are found in fish oils. The newly discovered lipids, called fatty acid hydroxy fatty acids, or FAHFAs, were lower in humans with early stages of diabetes and were much higher in mice resistant to diabetes.

"Based on their biology, we can add FAHFAs to the small list of beneficial lipids," says Alan Saghatelian, Salk professor in the Clayton Foundation Laboratories for Peptide Biology and one of the senior authors of the work. "These lipids are amazing because they can also reduce inflammation, suggesting that we might discover therapeutic opportunities for these molecules in inflammatory diseases, such as Crohn's disease and rheumatoid arthritis, as well as diabetes."

FAHFAs had not been noticed previously in cells and tissues because they are present in low concentrations, making them difficult to detect. Using the latest mass spectrometry techniques, Saghatelian and Barbara Kahn, vice chair of the Department of Medicine at BIDMC and the other senior author of the work, uncovered the FAHFAs when they examined the fat of a diabetes-resistant mouse model developed by Kahn.

"We engineered these mice to have more of a sugar transporter, called Glut4, in their fat because we had shown that when levels of this transporter are low, people are prone to developing diabetes," says Kahn. By examining how this sugar transporter might help protect against diabetes, the team noticed more fatty acid synthesis in mice that had improved insulin activity (and thereby were less likely to develop diabetes). The team collaborated to find out what lipids were involved.