In a new study, researchers found that a hormone that can suppress food intake and increase the feeling of fullness has shown similar results in humans and non-human primates.
The hormone, called Lipocalin-2 (LCN2), could be used as a potential treatment in people with obesity whose natural signals for feeling full no longer work.
The research was conducted by a team at Columbia University Irving Medical Center.
LCN2 is mainly produced by bone cells and is found naturally in mice and humans.
Studies in mice have shown that giving LCN2 to the animals long term reduces their food intake and prevents weight gain, without leading to a slow-down in their metabolism.
In the study, the team first analyzed data from four different studies of people in the US and Europe who were either normal weight, overweight or living with obesity.
The people in each study were given a meal after an overnight fast, and the amount of LCN2 in their blood before and after the meal was studied.
The researchers found that in those who were of normal weight, there was an increase in LCN2 levels after the meal, which coincided with how satisfied they felt after eating.
By contrast, in people who were overweight or had obesity, LCN2 levels decreased after a meal.
Based on this post-meal response, the researchers grouped people as non-responders or responders.
Non-responders, who showed no increase in LCN2 after a meal, tended to have a larger waist circumference and higher markers of metabolic disease—including BMI, body fat, increased blood pressure, and increased blood glucose.
Remarkably, however, people who had lost weight after gastric bypass surgery were found to have a restored sensitivity to LCN2—changing their status from non-responders before their surgery, to responders afterward.
Taken together, these results suggest that this loss of post-meal LCN2 regulation is a new mechanism contributing to obesity and could be a potential target for weight-loss treatments.
After verifying that LCN2 can cross into the brain, the team explored whether treatment with the hormone might reduce food intake and prevent weight gain.
They saw a 28% decrease in food intake compared with that before treatment within a week, and monkeys also ate 21% less than their counterparts who were treated only with saline.
Moreover, after only one week of treatment, measurements of body weight, body fat, and blood fat levels showed a declining trend in the monkeys.
These results show that the hormone can curb appetite with negligible toxicity and lay the groundwork for the next level of LCN2 testing for clinical use.
One author of the study is Peristera-Ioanna Petropoulou.
The study is published in eLife.
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