Antibiotics overuse leads to an imbalanced gut microbiome which is found to enhance cardiovascular mortality.
Dr Patrick C.H. Hsieh, lead author and research fellow at the Academia Sinica Institute of Biomedical Sciences (IBMS), Taiwan, and his research team found that overuse of antibiotics causes alteration in gut microbial composition.
The imbalanced microbiome affects the host immune system and impairs its function in cardiac repair after myocardial infarction. This increases myocardial infarction mortality. However, according to the researchers, the administration of Lactobacillus-based probiotics is able to enhance the post-infarction myocardial repair.
The number of human microbiota reside within and on human bodies is many-folds more than the number of cells comprising human bodies. These microbes co-exist with human from birth. The use of antibiotics suppresses some species and those favor the altered environment grow and flourish. The resulting dysbiosis, i.e. the altered microbial composition, cripples the immune response.
In the study, gut microbiota was depleted with antibiotics treatment, and the researchers observed drastically increased mortality in mouse myocardial infarction (MI) model. Most of these mice died with rupture in the left ventricle. The researchers found that the lack of short-chain fatty acids (SCFAs), one of the gut microbial metabolites, led to the findings.
SCFAs are the metabolites produced by gut microbiota through anaerobic fermentation of carbohydrates. They also serve as an important factor to modulate the function of immune cells. The injured myocardium stimulates the recruitment of macrophage and remove necrotic debris and apoptotic cells, followed by fibrosis to maintain cardiac structure. In the absence of SCFAs, cardiac repair mediated by immune cells is impaired and this increased the chance of cardiac rupture.
The team also suggests the supplementation of common Lactobacillus-based probiotics alters the gut microbial community in a favorable way that would enhance the function of cardiac repair.
In fact, gut microbiome is associated with not only cardiovascular diseases, but also obesity, diabetes, autoimmune diseases, cancer, and neuropsychiatric disorders.
The study was published online in Circulation on 8 October 2018.
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