NOV 16, 2018 12:04 PM PST

Liver gets activated by just seeing and smelling food!

Smell, sight and even thinking about food makes us salivate. This salivary reflex prepares us for digestion, as we need the saliva to help in the mastication process. But, this might not be the only one that prepares ahead for the digestive processes. Other known physiological changes initiated by food sensory perception are an increase in heart rate and the release of digestive enzymes. These pre-food intake responses prime the body and allow for rapid metabolism of nutrients post intake and effective removal from the circulation later. However, the role of peripheral organs the mediate these processes is not very well understood until now.

Recent work done by researchers from Max Plank Institute, Germany shows that the liver also gets activated by sight and the smell of food in anticipation of the prerequisite metabolic changes required for food intake. Through various high throughput screening, the authors have found evidence that the food cues transiently activate hepatic signaling to prime the liver for the nutrient intake. The molecular pathway involved has been elucidated. The study is published in Cell on November 15th.

Post food intake, blood insulin, and nutrient level increases and this, in turn, activates the liver via mechanistic target of rapamycin (mTOR) pathway and the endoplasmic reticulum (ER) stress response pathways. Hepatic signaling pathways induce the ER adaptation to increase protein-folding capacity that is essential for metabolic activities.  A previous study published in a cell by researchers from Department of physiology at the University of California have identified the neuronal pathways associated with the sensory perception of food. A rapid feedback response was observed before food intake.  

Building on this work, Jens Bruning’ team investigated the downstream pathways in which the neural signals translate to metabolic activities in the liver. Dr. Jens Brüning, an endocrinologist, geneticist, and director of the Max Planck Institute for Metabolism Research in Cologne, Germany is the senior author on the manuscript. He says that “This finding changes our view of one of the most fundamental processes in the body. The perception of food in the brain activates the liver in such a way that it begins preparing to receive the nutrients that it expects to come.”

Graphical abstract showing the signaling pathway activated when a mouse prepares to eat. Image Credit: Brandt et al. Cell, 2018.

Within five minutes of mice perceiving food, the rapid neuronal activity induced a signaling cascade that activated hepatic signaling pathways. Conventionally, these pathways are activated by the presence of circulating nutrients and uptake by the liver. “Our research shows that these changes in the liver occur in response to the mice seeing and smelling the food,” Brüning says. “It’s a whole coordinated program to prime the ER and get it ready for more proteins being synthesized and folded after eating.”

 Translation of this preclinical animal research to human’s and the potential therapeutic implications of such findings especially, in disease pathologies for diabetes and obesity does hold promise.

“There’s a possibility that this food sensory-dependent priming of the liver may be compromised in obesity. It could be a mechanism that contributes to insulin resistance,” Brüning explains. “Obesity may leave the liver unprepared for protein folding after eating, which in turn could disrupt the normal insulin response. This is something we plan to look at in future studies using obesity models in mice.”

Sources: Cell Press, Neuroscience News

About the Author
  • Aswini Kanneganti is an experienced research scientist from Dallas, Texas. Her interests include neuroscience, medical devices, and neuromodulation.
You May Also Like
JUN 11, 2020
Cancer
Fighting Cancer Stem Cells with Combination Therapy
JUN 11, 2020
Fighting Cancer Stem Cells with Combination Therapy
Pancreatic cancer is one of the most fatal cancers in the United States and is rapidly advancing up the ranks. The best ...
JUN 20, 2020
Cancer
A New MicroRNA Linked to the Suppression of Ovarian Cancer
JUN 20, 2020
A New MicroRNA Linked to the Suppression of Ovarian Cancer
One of the things a cancer patient can hear from their doctor is “recurrence.” Modern cancer therapies are a ...
JUN 21, 2020
Microbiology
Poor Oral Hygiene May Worsen Gut Inflammation
JUN 21, 2020
Poor Oral Hygiene May Worsen Gut Inflammation
Good dental hygiene benefits more than just the teeth and gums; researchers have found that poor oral health can contrib ...
JUN 30, 2020
Health & Medicine
UK Loosens Regulation on Prescription CBD for Epilepsy
JUN 30, 2020
UK Loosens Regulation on Prescription CBD for Epilepsy
Epidyolex-the epilepsy drug that contains the non-psychoactive cannabis chemical cannabidiol, or CBD-has been changed fr ...
JUL 09, 2020
Cardiology
Broken Heart Syndrome Found to Increase During Pandemic
JUL 09, 2020
Broken Heart Syndrome Found to Increase During Pandemic
Reporting in JAMA Network Open, scientists have found that broken heart syndrome, called stress cardiomyopathy, has been ...
JUL 12, 2020
Microbiology
Our Flu Response Is Influenced by Previous Exposures
JUL 12, 2020
Our Flu Response Is Influenced by Previous Exposures
The flu is caused by a respiratory virus, which evolves from year to year. Three kinds of influenza viruses infect human ...
Loading Comments...