Researcher Interview: Dr Kristen Bubb

What inspired you to follow a cardiac research career?

Initially I was interested in cardiology due to a family history of heart disease. I was very close to my grandfather and I used to go down to his dairy farm and we’d milk cows together. I spent a lot of time with him, but when I was in primary school he died suddenly of a heart attack at the age of only 60, which we were all shocked by. None of us were aware that he had any kind of heart disease or risk, he just dropped dead all of a sudden. That’s stayed with me my whole life and it is probably what drove me to cardiovascular sciences. I enjoyed learning the basics during my undergraduate Physiology classes and then during my honours year I did a project assessing the impact of intrauterine growth restriction on cardiac cells and coronary artery function in the offspring and enjoyed the research so much that I continued to a PhD and then a career in cardiovascular physiology.

What motivates or inspires your work?

I am motivated by the fact that heart disease remains our number one killer and we still have much to learn in order to improve treatments for patients. Despite this, it is inspiring that research has made a difference to the outcome for patients and we have seen a decrease in deaths over the last few decades. With further identification of patients at risk and better, earlier intervention, we should be able to continue to improve the prognosis for those suffering from and at risk of heart disease.

What project are you currently working on?

The project that I am currently working on is investigating unknown causes and potential treatment options for pulmonary arterial hypertension (high blood pressure in the arteries in the lungs).

This disease has a 100% mortality rate, with up to 50% of patients dying within five years of diagnosis. It is a rare disease but nevertheless is devastating for those who suffer from it. It often affects younger populations, people who are normally very independent and functional. The patient’s quality of life is poor, as they suffer from shortness of breath, dizziness, fatigue and chest pain.

This is due to the rise in blood pressure in the lung circulation which is caused by changes in the cells that line the pulmonary arteries. These changes can cause the walls of the arteries to become stiff and thicken. The blood vessels may also become inflamed and tight. Changes in the pulmonary arteries can reduce or block blood flow through the blood vessels which makes it harder for blood to flow, raising the blood pressure in the pulmonary arteries. As a consequence of this increased pressure the blood can build up behind the lungs, in the right side of the heart. This can result in the right- side heart having to pump harder to move the blood and it achieves this at first by the heart muscle growing larger and the chamber increasing.

However, eventually the right side of the heart will fail due to the extra load and this is what causes death in most patients.

Our research team have been working on a protein called FXYD1 for many years, and have shown the role that this protein has in protecting the heart from damage from free radicals. I have been investigating this protein in the blood vessels and have found that when it is absent the blood vessels have excessive free radical production and lose their ability to fully relax. Therefore, for my current project I proposed that this protein may be important in the pulmonary vasculature (lung blood vessels) and could be dysfunctional in patients with pulmonary hypertension.

Despite a number of different treatments currently available, patients ultimately need to be considered for lung transplantation, especially if they develop decompensated right-sided heart failure despite optimal medical management.

Our project has the real potential to translate into a life-saving treatment for patients with pulmonary hypertension. Improving pulmonary vascular health in these patients will likely improve their symptoms and quality of life, and as a result greatly impact patients’ families who are just as significantly affected by this disease as any other chronic debilitating and progressive illness.

You can read more about Kristen and her research here.