Dr. Sarah Wells

Dr. Sarah Wells

Dr. Sarah Wells

Pregnancy changes the heart:
Dr. Sarah Wells explores heart changes in pregnancy as potential heart failure cure

What do pregnancy and heart failure have in common? Both cause the heart to increase in size but, as Dalhousie biomedical engineer Dr. Sarah Wells points out, in pregnancy the valves get larger and more robust to support a blood flow that’s increased by nearly 50 per cent. In heart failure, the valves weaken and often tear as the heart struggles to pump enough blood.

“If we could identify the mechanisms that drive pregnancy-related changes to the heart, we might also have mechanisms we could harness to protect the heart and valves in heart failure,” says Dr. Wells, an associate professor in the School of Biomedical Engineering at Dalhousie University.

For the past 18 years, Dr. Wells has collected cattle hearts from local slaughterhouses to study how the hearts of cows who have never given birth differ from those of cows who have had one or even multiple calves.

“We study the structure, composition and function of the heart tissues in the various cows, to chart the changes that occur during pregnancy,” she says. “Among many things, we’ve found that pregnancy increases the amount of elastin in the cardiovascular tissues, compared to collagen. Elastin is very stretchy, while collagen is stiffer. This could offer a clue to treating diastolic heart failure, for example, which occurs when the heart gets too stiff to pump efficiently.”

Dr. Wells wants to know what is happening in pregnancy to drive the adaptive changes. “It could be hormones or a combination of hormones and higher mechanical loads,” she notes. “It could also be fetal stem cells circulating in the mother’s bloodstream.”

Soon Dr. Wells will be able to work with human tissues, secured through the tissue biobank at Dalhousie Medicine New Brunswick. Dalhousie Medical Research Foundation’s Spring 2019 Molly Appeal is supporting the further development of this biobank, which collects heart tissues and clinical data from patients in the Maritimes.

“The human data will be so valuable,” Dr. Wells says. “We will be able to see if the severity of a woman’s heart failure is related to how many pregnancies she had or any blood pressure or cardiac issues she may have experienced during pregnancy. Most importantly for us, we will gather clues about potential new approaches to therapy for heart failure.”

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