New study reveals key liver-brain communication pathway for managing eating patterns and obesity

In a groundbreaking study, researchers have identified a critical link between the liver and brain that helps regulate our daily eating patterns, offering a promising new approach for managing obesity.

This connection, facilitated by the hepatic vagal afferent nerve (HVAN), plays a role in aligning food intake rhythms with the body’s internal clock, or circadian rhythm. When this liver-brain pathway is altered, as seen in high-fat diets, it can lead to weight gain and metabolic disruption.

Circadian rhythms are natural 24-hour cycles that govern various physical, mental, and behavioural processes, including sleep and food intake, in sync with light and dark. In particular, the body’s master clock, located in the brain's suprachiasmatic nucleus, helps regulate these rhythms using cues like daylight. However, these rhythms can become disrupted by factors such as irregular eating or exposure to artificial light, which has been linked to higher risks of obesity, diabetes, and other metabolic disorders.

The liver has its own rhythm, which is tuned by the timing of food intake. This liver clock works closely with the brain’s master clock to regulate metabolism, helping to keep weight and blood sugar levels in balance. Disruptions in this coordination, such as eating at irregular times or consuming a high-fat diet, can lead to metabolic disorders.

Researchers sought to understand how the liver communicates with the brain to regulate eating patterns. Using a mouse model, they removed specific nuclear receptors (REV-ERBα/β) known for their role in metabolic rhythm regulation, allowing them to observe the effects of disrupted liver-brain communication on food intake patterns. They also surgically removed the hepatic HVAN, which transmits signals from the liver to the brain, to see if this nerve played a role in controlling eating rhythms and weight gain.

The study showed that altering this liver-brain pathway led to disrupted eating patterns, including increased food intake during the “light” period when mice would normally be less active and less likely to eat. This disruption caused significant weight gain. However, when the HVAN was surgically removed, it surprisingly reduced abnormal eating and resulted in weight loss.

This study’s findings suggest that targeting the HVAN or specific molecular pathways linked to the liver-brain connection could help create new anti-obesity treatments. By restoring normal communication between the liver and brain, it might be possible to re-establish healthy eating rhythms and metabolic balance, helping to prevent or manage obesity.