Aging Microbiome Linked to Cardiovascular Disease

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The aging microbiome may be somewhat responsible for the deterioration often seen in heart health as we age according to a new study from the University of Colorado Boulder.

The risk of cardiovascular disease increases significantly as we age and is associated with stress-mediated arterial dysfunction.

Almost three-quarters of Americans aged 60-79 suffer from some form of heart disease.

A growing body of research suggests that the gut microbiome plays a pivotal role in heart health. Inspired by this, scientists at the University of Colorado Boulder wanted to know whether there was a direct link between alterations in the gut microbiome and arterial dysfunction.To address this question, the scientists treated old and young mice with broad-spectrum antibiotics to kill off their resident bacteria.

After a few weeks of antibiotic treatment, the young mice showed no changes in the health of their arteries; however, the old mice showed significant improvements in several vascular health measures.

In a nutshell, the arteries of the elderly mice were restored to that of the young mice.

This remarkable finding suggests that there is something about the aged microbiome that has a negative impact on heart health.

It is well known that as we age, the diversity of bacteria in our microbiome diminishes. This lack of diversity results in an imbalance called dysbiosis, which could be contributing to the arterial damage.

To identify specific factors that could be driving cardiovascular disease, the scientists carefully studied the microbiomes of the old and young mice.

They found that the microbiomes of the elderly mice had increased numbers of bacteria that are pro-inflammatory and have previously been associated with disease.

Notably, one particular metabolite – TMAO – was present at much higher levels in the microbiomes of the old mice.

TMAO (trimethylamine N-oxide) has previously been linked to atherosclerosis and stroke.

While it’s still too early to draw firm conclusions, increasing evidence suggests that as we age the gut microbiome deteriorate and begins producing toxic molecules, including TMAO, which get into the bloodstream, cause inflammation and oxidative stress and damage tissue.

The researchers are currently focusing on the effects of different diets on gut health and cardiovascular disease in humans. Notably, a compound called dimethyl butanol, which is found in red wine and olive oil, has been found to block the production of TMAO and could be part of the reason that the Mediterranean diet is good for heart health.

Reference:

Brunt, V. E. et al. (2019). Suppression of the gut microbiome ameliorates age‐related arterial dysfunction and oxidative stress in mice. The Journal of physiology.