Another Controller of Appetite and Weight
We recently discussed the role of cytokines in modulating appetite and energy balance. Now a study in mice has shown that animals deficient in interleukin-18 (IL-18) develop a voracious appetite, very marked obesity and insulin resistance. The insulin resistance is secondary to the obesity that was induced by increased food intake and occurred in the liver as well as muscle and fat.
When the little creatures were given recombinant IL-18 their food intake returned toward normal.
Only recently discovered, IL-18 is an important regulator of innate and acquired immune responses. The fact that a modulator or immunity and inflammation has a key role in feeding and in energy metabolism shows us once again just how closely all these systems are tied together. You lose weight when you are sick or depressed because the body is battling the illness. As you recover, the body needs to replace everything that was lost and re-establish your resilience. These systems don’t just exist in humans, they are found in all mammals and even some birds and fish. So they have evolved over millions of years and we need to be very careful about tinkering with these complex systems. Or of allowing stress or environmental toxins to compromise these protective mechanisms.
This finding may well pave the way not just for new pharmacological approaches to weight management, but also to some non-pharmacological approaches.
Technorati tags: Cytokines Weight management Insulin resistance Interleukin-18 Inflammation