“Everything in Nature is connected. Only human-made machines are linear.”
~Fritjof Capra, Philosopher & Physicist
We like to think of ourselves as individuals, Captains of our fate, charting the course over rugged and unforgiving seas. But we are more the ship, dependent upon a diligent crew to attend to our needs, keep us seaworthy, and point us in the right direction. Lest we float at the mercy of the tides, an aimless Flying Dutchman. Regardless of which vantage point you prefer, the fact remains that both company and craft must function as a single ecosystem for the survival of all.
The current body of data makes it clear that humans exert considerable control over their gut microbiota through the choices we make in selecting what to eat; bad choices, bad crew. And when the sea conspires in sullen anger, that is precisely when the character of your crew matters most.
A recent study presented at the European Society of Cardiology examined how the state of an individual’s gut bacteria can impact the life-threatening side effects of chemotherapy in women undergoing this therapy for the treatment of breast cancer.
- The study examined 98 women over the age of 60 diagnosed with breast cancer as part of a larger EU-funded project known as CARDIOCARE.
- The women were tested for specific biomarkers that indicate the state of their heart health, and their gut bacteria genome was sequenced before chemotherapy.
- Specific bacteria in patients’ gut microbiomes correlated with biomarkers, suggesting a greater risk of heart damage during chemotherapy.
- This pilot study provided the groundwork for a larger 600-patient study underway to confirm these findings.
The Caveat:
This research contributes to the growing body of evidence linking individual health and functioning to epigenetic phenomena, such as the gut microbiome, in an increasingly complex relationship. In this pilot study, scientists found that specific bacteria in patients’ gut microbiomes correlated with heart health biomarkers, suggesting they are at a greater risk of heart damage during chemotherapy, a phenomenon known as cardiotoxicity.
The study recruited 98 women over the age of 60 who were diagnosed with breast cancer from three clinical treatment centers across Europe: the Bank of Cyprus Oncology Centre, Cyprus; the National and Kapodistrian University of Athens, Greece; and the European Institute of Oncology, Italy.
The women received echocardiograms, an ultrasound test that measures cardiac function, and various blood tests to evaluate specific biomarkers known to correlate with increased cardiac risk. Using the cardiac ultrasound, researchers were able to assess Left Ventricular Global Longitudinal Strain (LVGLS). LVGLS is a more sensitive measure of the more familiar echocardiographic ejection fraction for detecting subtle changes in left ventricular (LV) cardiac function. Normal values are around -15% to -20% (the more negative a value, the better the heart function). Values greater than -15.2% (less negative) are associated with greater myocardial dysfunction and higher mortality rates.
Blood tests measured NT-proBNP and Troponin I. The elevation of these biomarkers correlates with the presence of heart failure and a greater early mortality risk. Genetic sequencing was used to profile all the bacteria in the gut of the patients before they received cancer treatment, which included standard chemotherapy.
Women who demonstrated worse LVGLS values and elevated blood markers of cardiac risk also exhibited specific bacterial patterns in their gut microbiota. The gut microbiome abnormalities were similar to those found in patients already suffering from clinical heart failure symptoms, including an increase in the bacterial species Bacteroides. This species is a very common gut bacterium, but when its populations are dysregulated, it can cause systemic havoc.
“This study is one of the first to ask whether the microbiome could play a role in how well patients’ hearts fare during chemotherapy,” explained Dr. Athos Antoniades, one of the study leaders. He continued, “We saw a clear association between some specific genera of gut bacteria and cardiac biomarkers that suggest patients are at greater risk of heart damage during chemotherapy…To allow cancer survivors healthier lives, we need to find new ways to protect them from the long-term side effects of chemotherapy. While further research is needed, it does give us the tantalizing hope that tailored probiotics could play a role in protecting patients against the harmful effects of cancer treatment in the future.”
The closer we look, the fuzzier the boundary between ourselves and our environment.
The Study:
