How a cytokine in your brain regulates your body weight?

According to figures, there are more than 1.9 billion overweight people, about one-third of whom are obese. Obesity hides the possible dangers of multiple diseases, so successful anti-obesity treatments are desperately needed.

It is well-known that interleukin-6 (IL-6) is a pro-inflammatory molecule that’s part of the innate immune system. However, researchers in the University of Gothenburg in Sweden have discovered a link between IL-6 from the brain and obesity. Through experiments in mice and rats, they confirmed that IL-6 does influence the risk of obesity and where this effect happens in the mind.

Interestingly, the brain’s control and utilization of IL-6 could be different from different parts of the body. The investigators wanted to know what happens to the level of IL-6 in the brain after a diet that leads to obesity.

Throughout the experiment, the researchers fed rats and mice with high-calorie foods like fat and hot mix. All these rodents, like humans, opt to eat too much when they eat foods that are high-calorie.

Obese mouse with low IL-6 brain levels

They discovered that IL-6 was reduced in fat rats and mice, but only in a region of the brain called the parabrachial nucleus (lPBN).

To research whether the reduction in IL-6 is bad or good for the metabolic health of rodents, the group has very selectively reduced the degree of IL-6 in lPBN by viral inheritance. The result is that even for rodents with a healthy diet, their weight and fat increase.

Consequently, the researchers believed that a drop in lPBN IL6 levels in obesity may lead to metabolic dysfunction and weight reduction. Since body weight is the result of energy intake and energy expenditure, any dysfunctionality in either of the 2 branches of energy equilibrium leads to weight gain.

After additional study, the team discovered that IL-6 made by the parabrachial nucleus affects both branches, namely, it reduces food intake and increases energy expenditure, while the latter increases brown fat action, so the body’s energy is used to create heat or burn fat. Therefore, lowering the IL-6 amount in lPBN breaks the whole energy balance.

Early studies in the University of Gothenburg have demonstrated that serum IL-6 levels in obese and overweight men are elevated but mind IL-6 levels measured in cerebrospinal fluid have been reduced.

The researchers also found that the decrease in IL-6 connected with obesity has been just found in men. Female rats and mice have normal IL-6 levels. The study team is currently investigating why women are immune to obesity-related IL-6-driven dysfunction.