Cambridge Study Reveals Brain Receptor Insights for Weight Loss Treatments

Researchers at the University of Cambridge have discovered that both activating and blocking the glucose-dependent insulinotropic polypeptide receptor (GIPR) can contribute to weight loss, suggesting new approaches for obesity treatment. The findings, detailed in a study published in Nature Metabolism, indicate that the effectiveness of these strategies depends on the targeted brain region.

Targeting Different Brain Regions

The study, which focused on mice, found that activating GIPR in the brainstem resulted in reduced appetite, while blocking the same receptor in the hypothalamus achieved weight loss through a different mechanism. The hypothalamus appears to limit the strength of fullness signals from the brainstem; blocking GIPR in this region released this ‘brake,’ enhancing the response to satiety signals.

Currently, over a billion individuals globally suffer from obesity, a condition that heightens the risk for multiple diseases including type 2 diabetes, cardiovascular disease, and cancer. While significant weight loss through diet and exercise is challenging, new medications targeting specific brain receptors offer potential solutions.

Advances in Weight Loss Medications

Modern weight loss drugs, such as Wegovy and Ozempic, activate the glucagon-like peptide 1 receptor (GLP-1R), influencing appetite-related receptors to reduce food intake and promote weight loss. Other treatments, including Mounjaro and Zepbound, focus on activating GIPR, while some, like MariTide, inhibit it.

The research team utilized genetically engineered mice to analyze the effects of these drugs, removing GIPR from specific brain areas. Monitoring various combinations of GIPR agonists and antagonists alongside GLP-1 drugs, they evaluated changes in food consumption, body weight, and blood sugar control.

Potential for Combination Therapies

Findings from the study suggest that GIPR antagonists might enhance the effectiveness of new drugs targeting the amylin receptor, possibly strengthening various classes of obesity treatments. The results illuminate the effectiveness of drugs like MariTide, which is currently in phase 3 clinical trials and combines GIPR antagonism with GLP-1 receptor agonism.

Dr. Jo Lewis, the study’s first author, emphasized the significance of understanding brain circuits in designing better obesity medications that yield more weight loss with fewer side effects. She stated, “Our work also strengthens the idea that the brain is central to obesity treatment. Obesity drugs are not acting simply on the gut or pancreas. Instead, they have important effects on specific, identifiable brain circuits that regulate appetite and food intake.”

This research was funded by the Medical Research Council and Wellcome.