'Good' fat that can fight diabetes discovered

Scientists have discovered a new class of molecules - produced in human and mouse fat - that can protect against diabetes.
Researchers at the Salk Institute and Beth Israel Deaconess Medical Center (BIDMC) in Boston found that giving this new fat, or lipid, to mice with the equivalent of type 2 diabetes lowered their elevated blood sugar.
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 utilised as a therapy for metabolic disorders.
The new 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," said 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," Saghatelian said.

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," said 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).
"While many of the other lipids were essentially the same between normal mice and these diabetes-resistant mice, we saw these FAHFA lipids elevated by sixteen fold in mice that were resistant to diabetes, standing out really clearly as a big change," said Saghatelian.

Once they identified FAHFAs as being the lipid that was different between normal mice and these diabetes-resistant mice, they found something else important: when the mice eat FAHFAs, blood sugar levels dropped and insulin levels rose, indicating the potential therapeutic value of FAHFAs.
To determine whether FAHFAs are also relevant in humans, the team measured FAHFA levels in humans who are insulin-resistant (a condition which is often a precursor to diabetes) and found that their FAHFA levels were lower in fat and blood, suggesting that changes in FAHFA levels may contribute to diabetes.