A study conducted by IMPACT, from the University of the Andes, the Universidad del Desarrollo, and the University of Chile found that gut microbiota not only influences our physical health, but also our behavior, including the consumption of addictive substances such as alcohol.
The results of this study, recently published in the leading international scientific journal in the field of extracellular vesicles, Journal of Extracellular Vesicles, suggest that small extracellular vesicles derived from intestinal bacteria (called bEVs) act as mediators of communication between the microbiota and the brain, directly influencing alcohol consumption.
The gut microbiota, composed of trillions of microorganisms that reside in our digestive tract, plays a crucial role in regulating multiple physiological functions, including digestion, metabolism, and communication with the central nervous system. For this research, extracellular vesicles derived from the gut microbiota of rats with high alcohol consumption were administered to rats that normally reject this substance, observing a dramatic increase in their alcohol intake. In addition, it was identified that this effect depended on the vagus nerve, a key channel in communication between the gut and the brain. Surprisingly, the increase in alcohol consumption was not accompanied by systemic or cerebral inflammation, suggesting that the underlying mechanism is independent of inflammatory responses.
For IMPACT’s principal investigator, Francisca Alcayaga, these findings highlight the importance of investigating the gut microbiota as a potential regulator of addictive behavior.
“Understanding how the microbiota contributes to a predisposition to alcohol consumption is essential for developing innovative therapeutic strategies that address alcohol use disorder from a new perspective. The identification of bEVs as a possible mediator of this addictive behavior opens the door to future studies that could lead to the design of interventions aimed at modulating the gut microbiota to prevent or reduce vulnerability to excessive alcohol consumption,” she explains.
When asked whether the results could suggest that the transfer of microbiota from parents to their children could influence their future alcohol consumption, Fernando Ezquer, an academic at the Universidad del Desarrollo and part of the team behind the study, points out that: “If we consider that the microbiota is inheritable and at the same time is a cause of problematic alcohol consumption, it is logical to think that consumption is also an inheritable factor mediated by the transfer of the microbiota, which occurs at birth. However, at the molecular level, bEVs have been detected in amniotic fluid in both humans and animal models, so the microbiota could be predisposing the individual to high alcohol consumption from gestation onwards, mediated by bEVs.”
New questions about addiction
One of the questions that this study raises within the research team is whether these extracellular vesicles could have an impact on the consumption of other addictive substances. “This publication is the first in the world to attribute causality to microbiota bEVs in an addiction model. We will definitely evaluate soon whether this phenomenon is replicable with other drugs of abuse, as we have years of experience in the field of addiction, experimental designs, and a highly qualified team to carry out these tests,” says Fernando Ezquer.
For the IMPACT scientist, advancing this question is essential. “Until now, the impact of these extracellular vesicles has been explored in the context of alcohol consumption, but their possible role in dependence on other substances, such as psychoactive drugs, is a fascinating line of research that must be explored. If this mechanism turns out to be a key factor in addiction in general, it could represent a new paradigm in the understanding and treatment of addictive disorders,” she says.
The results of this work not only contribute to the understanding of the connection between the gut and the brain in the context of addictive behavior, but also establish a reference protocol for the isolation of bEVs that is developed entirely in Chile by the IMPACT center, through the participation of researcher Francisca Alcayaga-Miranda and senior research assistant Aliosha Figueroa-Valdés. This protocol allows these structures to be obtained in their purest form and characterized in detail, providing a valuable tool for future research in the field of microbiota and its impact on human health.