# Potential Role of Probiotic Strain Lactiplantibacillus plantarum in Control of Histamine Metabolism

## TL;DR

This study shows that the probiotic Lactiplantibacillus plantarum LP115 can boost DAO enzyme levels, which helps break down histamine, potentially aiding in histamine intolerance.

## Contribution

The novel finding is that L. plantarum LP115 increases DAO secretion without altering its protein expression, offering a new approach for managing histamine intolerance.

## Key findings

- L. plantarum LP115 increased DAO secretion in HT-29 cells after 4 hours.
- DAO levels in the culture medium were reduced, indicating histamine degradation.
- No toxicity was observed, and DAO protein expression remained unchanged.

## Abstract

The study investigates the probiotic Lactiplantibacillus plantarum LP115 and its effect on histamine metabolism. In vitro tests on HT-29 intestinal cells showed that after 4 h of contact, the probiotic significantly increased the secretion of diamine oxidase (DAO), the key enzyme in degrading histamine, and reduced histamine levels in the culture medium. No toxicity was observed. The probiotic did not alter DAO protein expression, suggesting the release of preformed DAO vesicles. Findings support the potential of L. plantarum LP115 in managing histamine intolerance.

Histamine intolerance is a condition that occurs when there is an imbalance between the accumulation and degradation of histamine within the body. Excess histamine is metabolized and then degraded by two enzymes, of which the most abundant is the vesicular diamine oxidase (DAO). An imbalance or a state of dysbiosis of the intestinal microbiota has been observed in patients with histamine intolerance compared to healthy individuals. Studies indicate that the administration of bifidobacteria or lactobacilli alone or in mixtures can alter colonic microbiota populations and metabolic activities. The present study has evaluated the ability of a probiotic bacterial strain to stimulate the release of cellular DAO from an in vitro model of the human intestinal epithelial barrier. The results indicate that, under the experimental conditions used, probiotic strain Lactiplantibacillus plantarum LP115 has a significant stimulatory effect on DAO secretion in adenocarcinoma cell line HT-29.