Acarbose redirects dietary carbohydrate utilization by gut bacteria to suppress mast-cell-dependent anaphylaxis in mice, with succinate identified as a key effector metabolite, and a human cohort analysis revealing lower anaphylaxis incidence in patients treated with α-glucosidase inhibitors.
Key Findings
Results
Acarbose, an α-glucosidase inhibitor, suppresses mast-cell-dependent systemic anaphylaxis in mice independently of adaptive immune responses.
Acarbose is a widely used antidiabetic agent that inhibits α-glucosidase activity in the gut.
The suppression of anaphylaxis was shown to be independent of adaptive immune responses.
The mechanism involves redirection of dietary carbohydrate utilization by gut bacteria.
Mast cell degranulation was identified as the target cellular process being suppressed.
Results
Acarbose treatment enhanced carbohydrate availability in the gut, promoting proliferation of Parabacteroides distasonis in mice.
Enhanced carbohydrate availability resulted from α-glucosidase inhibition reducing host absorption of dietary carbohydrates.
Parabacteroides distasonis was specifically identified as the bacterium whose proliferation was promoted.
The finding links a pharmacological intervention to a specific shift in gut microbial composition.
This represents a microbiota-accessible carbohydrate-mediated modulation of gut microbial composition.
Results
Proliferation of Parabacteroides distasonis led to increased succinate abundance and elevated intracellular NAD+ levels, with reduced reliance on b-type cytochrome-dependent anaerobic respiration.
Succinate abundance was increased as a result of enhanced Parabacteroides distasonis activity.
Intracellular NAD+ levels were elevated in association with these metabolic changes.
Reduced reliance on b-type cytochrome-dependent anaerobic respiration was observed.
These metabolic changes represent a previously unrecognized pathway linking dietary carbohydrate metabolism to immune regulation.
Results
Direct administration of succinate suppressed systemic anaphylaxis in mice and inhibited mast cell degranulation in vitro, implicating succinate as a key effector metabolite.
Succinate was directly administered to mice and shown to suppress systemic anaphylaxis.
In vitro experiments demonstrated that succinate suppressed mast cell degranulation.
These results implicate succinate as a key effector molecule in the microbiota-mediated suppression of allergic responses.
The findings establish a mechanistic link between gut microbial metabolite production and peripheral mast cell function.
Results
A human cohort analysis revealed that patients treated with α-glucosidase inhibitors showed a lower incidence of anaphylaxis compared to untreated individuals.
The human cohort analysis examined patients treated with α-glucosidase inhibitors versus untreated individuals.
Lower incidence of anaphylaxis was observed in the treated group.
This finding provides translational evidence supporting the relevance of the mouse model findings to human health.
The analysis suggests that the gut-microbiota-mediated pathway identified in mice may operate in humans.
Conclusions
The study uncovers a previously unrecognized gut-microbiota-mediated pathway linking dietary carbohydrate metabolism to systemic immune regulation.
The pathway operates through microbiota-accessible carbohydrates shaping gut microbial composition and metabolism.
This represents a novel mechanism by which dietary carbohydrate modulation can influence systemic allergic responses.
The findings are distinct from previously characterized microbiota-immune interactions involving adaptive immunity.
What This Means
This research suggests that acarbose, a common diabetes medication that slows sugar digestion in the gut, can also protect against severe allergic reactions (anaphylaxis) by changing how gut bacteria process carbohydrates. When acarbose blocks the breakdown of dietary carbohydrates in the intestine, more of those carbohydrates become available to gut bacteria. This feeds a specific bacterium called Parabacteroides distasonis, which then produces higher amounts of a molecule called succinate. The researchers found that succinate can directly calm down mast cells — the immune cells responsible for triggering allergic reactions — thereby reducing the severity of anaphylaxis. Importantly, this protective effect worked independently of the immune system's adaptive branch (antibodies and T cells), suggesting it is a distinct biological pathway.
The researchers confirmed these findings in multiple ways: by conducting mouse experiments with acarbose treatment and direct succinate administration, by performing laboratory experiments showing succinate suppresses mast cell activation, and by analyzing data from human patients. In the human cohort, people who were taking α-glucosidase inhibitors (the class of drugs that includes acarbose) had a lower rate of anaphylaxis than people who were not taking these drugs, suggesting the mouse findings may translate to humans.
This research suggests that a widely available, commonly used diabetes drug may have an unexpected benefit in reducing severe allergic reactions, mediated through the gut microbiome. It also points to succinate as a potential therapeutic target for allergy treatment, and highlights how dietary carbohydrate availability can influence systemic immune responses through gut bacteria — a previously unrecognized biological connection.
Yakabe K, Inoue Y, Yanagisawa Y, Imai S, Suwa S, Ando M, et al.. (2026). Acarbose redirects gut microbiome utilization of dietary carbohydrates to suppress anaphylaxis in mice.. Nature microbiology. https://doi.org/10.1038/s41564-026-02350-2