Could the gut microbiota be partially responsible for aggressive behaviors? A new study questions the impact of antibiotics administered in the first days of life.
Israeli researchers have discovered that altered microbiota in infants might influence aggressiveness, a finding that raises concerns about the early use of medications.
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The scientific team from Bar-Ilan University explored the effect of fecal transplantation using mice. These transplants came from human infants who had received antibiotics or had not. The results show a significant difference in behavior. Rodents that received an altered microbiota exhibited increased signs of aggressiveness compared to the others. The scientists also observed changes in serotonin and tryptophan levels in the brain.
This study reveals that disturbances in intestinal microbiota can directly influence neurochemical mechanisms linked to aggression. The septum pellucidum, a region of the brain associated with aggression regulation, seems particularly affected. While antibiotics are effective in fighting infections, they can have lasting effects on the microbiota. This imbalance may influence vital processes well beyond gut health.
Researchers hope these findings will lead to new therapeutic avenues. Understanding the role of the microbiome could help treat certain behavioral disorders, including aggressiveness. These discoveries pave the way for future work on how to preserve microbiota balance from birth. Therapeutic strategies could thereby prevent undesirable alterations.
What is the gut microbiota?
The gut microbiota refers to the collection of microorganisms living in our digestive tract. It is made up of billions of bacteria, viruses, fungi, and other microbes. These microorganisms coexist in symbiosis with the human body, contributing to essential functions such as digestion, protection against pathogens, and regulation of the immune system.
The gut microbiota plays a key role in overall health. It helps ferment dietary fibers, synthesizes vitamins, strengthens the intestinal barrier, and communicates with the brain through the gut-brain axis. Disruptions in this balance, called dysbiosis, are associated with various diseases, including digestive disorders, chronic inflammatory bowel diseases, and even certain neuropsychiatric disorders like anxiety or depression.
The gut-brain axis allows the microbiota to communicate with the central nervous system through nerve pathways (notably the vagus nerve), hormonal and immune routes. Gut bacteria produce neurotransmitters such as serotonin and influence systemic inflammation, thereby altering behaviors and emotions. Studies on this axis show that disturbances in the microbiota can affect behaviors such as aggressiveness, as observed in mice in this recent research.
Article author: Cédric DEPOND