Neural mechanism responsible for fat breakdown

Washington D.C.: From brain, to fat, to weight loss, a new study has revealed the neural mechanism responsible for fat breakdown.

Weight is controlled by the hormone leptin, which acts in the brain to regulate food intake and metabolism. However, it was largely unknown until now, how the brain signals back to the fat tissue to induce fat breakdown.

Now, a breakthrough study led by Ana Domingos at Instituto Gulbenkian de Ciencia (IGC; Portugal), in collaboration with Jeffrey Friedman's group at Rockefeller University (USA), has shown that fat tissue is innervated and that direct stimulation of neurons in fat is sufficient to induce fat breakdown. These results set up the stage for developing novel anti-obesity therapies.

The research team led by Ana Domingos, combined a variety of techniques to functionally establish, for the first time, that white fat tissue is innervated.

Co-first author Roksana Pirzgalska said that they used a powerful technique called optogenetics, to locally activate these sympathetic neurons in fat pads of mice, and observed fat breakdown and fat mass reduction.

Domingos added that the local activation of these neurons, leads to the release of norepinephrine, a neurotransmitter, that triggers a cascade of signals in fat cells leading to fat hydrolysis. Without these neurons, leptin is unable to drive fat-breakdown.

Domingos concluded that this result provides new hopes for treating central leptin resistance, a condition in which the brains of obese people are insensitive to leptin.

The study is published in the latest issue of the prestigious journal Cell.