Learning about heart

CYNTHIA RAMSAY

According to Statistics Canada data for 2011 found on the Heart and Stroke Foundation website, “Since 1952, the cardiovascular death rate in Canada has declined by more than 75 percent – and nearly 40 percent in the last decade – largely due to research advances in surgical procedures, drug therapies and prevention efforts.” Nevertheless, “Every seven minutes in Canada, someone dies from heart disease or stroke” and heart disease and stroke remain two of the leading causes of death in Canada.

Imagine if our hearts could regenerate? Imagine if we could prevent heart disease? Failing that, imagine that, man or woman, we received proper and timely treatment when we had a heart attack, stroke or other heart ailment? To show that the imagined is possible, Weizmann Canada and Shoppers Drug Mart are presenting the Women’s Health Learning Series across seven Canadian cities, including Vancouver, where The Heart of the Matter took place on April 10. The series includes bone-health lectures, as well, and each lecture features a Weizmann Institute of Science researcher and a local physician, as well as a Shoppers pharmacist.

In Vancouver, Dr. Rachel Sarig, from the department of biological regulation at the Weizmann Institute in Israel, presented some of the research on heart disease in which she is participating, while Vancouver General Hospital cardiologist Dr. Tara Sedlak, who is also medical director of the Leslie Diamond Women’s Heart Health Clinic, busted the main myths surrounding women and heart disease. The event was emceed by Susan Stern, Weizmann Canada’s national executive vice-president, and it featured a short video providing background on the Weizmann Institute. Shoppers Drug Mart pharmacist Genette Ret-Davis gave an overview of Shoppers’ women’s health initiatives, heart disease and how it affects women, and introduced Sarig and Sedlak.

Sarig, who is also a member of the editorial board of World Journal of Stem Cells and that of Stem Cell Discovery, spoke with great clarity on a very complicated topic: the research being conducted on cardiac cells (cardiomyocytes) in an effort to facilitate heart regeneration. After giving examples of animals – flatworms, a type of salamander, zebrafish “and, unfortunately, also cockroaches can regenerate” – she noted that “all mammals, including human beings, lost this remarkable capacity to regenerate. So, we may ask why we have lost this, but since we are not philosophers, we are researchers, more practical, we can ask, ‘How can we restore this remarkable capacity?’”

She continued, “So, what is a heart failure, what is more commonly termed a heart attack? Of course, there are numerous heart conditions, and this just describes one of them. You don’t eat properly, you don’t exercise, there’s a lot of stress on your mind, perhaps you smoke ... what is described here is an ischemic event, which means that a plaque starts to form in one of the arteries and it builds the blood flow and oxygen to part of the heart and this is what leads to the heart attack, scientifically termed myocardial infarction. And, the part of the heart that doesn’t get this blood supply and oxygen, the cells in this part die, and the important cells that compose the cardiac tissue are called cardiomyocytes. These are the important cells that beat and contract and, once they die, since we are mammals, we cannot regenerate ... this damaged tissue, but something has to seal this damage and that something is another cell type, these are called fibroblasts. Fibroblasts are very important in various wound healings, including in the heart, and they are recruited to the damaged area and these fibroblasts can proliferate ... and they also secrete various proteins to seal the damage, mainly collagens, so, instead of forming new cardiac tissue, what you are getting is a scar formation, which, of course, impairs very much the heart function.”

A couple of years ago, there was a breakthrough, said Sarig, when researchers found that there is a mammal that can regenerate: one-day-old mice. At seven days old, however, this ability is lost, so the question is how the one-day and seven-day heart cells differ. Sarig explained four main approaches to the research on improving heart function: stimulating the proliferation of cardiomyocytes; the use of stem cells that reside in various tissues or organs within our body; the use of stem cells from a donor, trying to propagate them and transplanting them back into the damaged heart; and blocking cell death. She postulated that the future likely will be “a combined therapy of using several approaches, both stem-cell therapy, as well as trying to find out drugs that induce the natural renewal of the endogenous cardiomyocytes in the heart, just like it happens in the zebrafish and in one-day-old mice.”

When Sedlak, the only certified women’s heart health cardiologist in Canada, took to the podium, she tackled some of the misconceptions about heart disease and women in the areas of symptoms, causes and treatment.

About the symptoms of a heart attack, Sedlak explained that the research shows that approximately the same percentage of women (53) and men (56) experience chest pain as a main symptom; that throat, jaw and neck pain is more common in women; and that weakness and/or fainting, less common symptoms, are more often found in the elderly and, since women generally have heart attacks about 10 years later than men, they more often have these atypical symptoms.

Sedlak said that plaque in the arteries appears in more than 90 percent of men with a heart attack, but only 70 percent of women, and that there are other causes of heart attack in women: a tear in the artery, a spasm of the artery and microvascular (small vessel) disease. These different causes are still under-recognized, she said, which means that many women are sent home despite experiencing a heart attack, the symptoms being disregarded by medical professionals because no plaque can be found. She went on to discuss in more depth microvascular coronary dysfunction, its diagnosis and treatment, then focused on two other misconceptions: that hormone replacement therapy is either good or bad for all women, and that calcium supplements are good for all women, discussing the risks and benefits of both.

An approximately 25-minute question-and-answer period followed the speakers’ presentations, and the event closed with a reception. About 60 people attended the lecture, which took place at the Norman and Annette Rothstein Theatre.

^TOP