Gut bacteria linked to heart damage from chemotherapy

A healthy gut microbiome before chemotherapy may help protect breast cancer patients from heart damage caused by treatment, new research suggests.

Scientists found that specific gut bacteria were linked to biomarkers associated with increased risk of cardiotoxicity – damage to the heart muscle as a result of cancer therapies.

The study examined the gut microbiome – the population of bacteria in the digestive tract – in 98 women over the age of 60 with breast cancer, before they began chemotherapy.

Researchers used genetic sequencing to identify the types of bacteria present and compared this with indicators of heart health.

Participants underwent echocardiograms – ultrasound scans to assess heart function – and blood tests to measure biomarkers linked to heart damage.

These included LV-GLS, NTproBNP and Troponin I, which are proteins that signal stress or injury to the heart.

Researchers found that a group of bacteria called Bacteroides were more common in patients whose test results indicated higher susceptibility to cardiotoxicity.

The gut microbiome profile in these women resembled that found in patients with heart failure.

Dr Athos Antoniades is head of research and development at Stremble Ventures, who is leading the multi-omics analysis including gut microbiome DNA sequencing.

Antoniades said: “To allow cancer survivors healthier lives, we need to find new ways to protect them from the long-term side-effects of chemotherapy.

“This study is one of the first to ask whether the microbiome could play a role in how well patients’ hearts fare during chemotherapy.

“We saw a clear association between some specific genus of gut bacteria and cardiac biomarkers that suggest patients are at greater risk of heart damage during chemotherapy.

“While further research is needed, it does give us the tantalising hope that tailored probiotics could play a role in protecting patients against the harmful effects of cancer treatment in future.”

Bacteroidaceae, the bacterial family that includes Bacteroides, are commonly found in the human gut.

While often beneficial, they may contribute to infection and inflammation if their populations become unbalanced.

Cardiotoxicity is a relatively common side-effect of several cancer treatments, including chemotherapy.

As more patients survive breast cancer, growing numbers are living with the long-term consequences of treatment.