Toronto doctors have performed Ontario’s first cardiac stem cell transplant using bone marrow cells of the patient in question.
Cardiac surgeon Dr. Terrence Yau explains the trial that 67-year-old patient James Culross is involved in, and what it could mean for the 50,000 Canadians diagnosed each year with advanced heart failure.
What happens to the heart when somebody has a heart attack?
It means that part of the heart muscle dies because it didn't get enough blood flow. In a large heart attack, the patient is more likely to die, but even if they survive, it always weakens the heart to some extent. And the bigger the heart attack that somebody had, the more likely they are to have heart failure as a consequence.
What can stem cells do for patients who suffer from heart attacks?
So really the hope is that stem cells can be developed into a therapy that will allow us to treat that heart attack and improve the heart in a way that conventional therapies like bypass surgery and stents cannot. So the cells that we implant may then be able to improve the function, wheezing ability and the blood flow of that part of the heart where the heart attack was.
What do the stem cells do in the heart?
In fact, these cells work through very different mechanisms than we understood a number of years ago and it is really not by making new heart muscle cells, which in retrospect is a very simplistic view, but really by sort of harnessing the endogenous repair mechanisms of the heart and by getting the cells that survived in the heart to work better and work harder.
How long will it take to determine whether the stem cells have helped the patient?
We'll be able to evaluate all these patients six months after their implants to try and demonstrate differences between patients who have had the stem cells implanted and those who did not, so that we can figure out exactly the effect the cells themselves had. We know that simply by doing a bypass surgery, we'll make these patients better in a lot of ways, so now what we need is to demonstrate the cells achieve an impact over and above bypass surgery.
If the trial is deemed safe and effective, ultimately how important could this be for cardiac patients?
The promise of stem cell therapy is, as I'm sure you have heard, tremendous. The sad reality is that because we don't have enough donor hearts, and we don't-as a society-have the resources to really be able to put a mechanical heart into everybody, we're looking now for a therapy that may be applied to the vast population of patients who are going to qualify for heart transplants, and for whom medications alone are not enough. And so that is tens of thousands of patients every year.
How is trial patient James Culross doing after the treatment?
He actually has done remarkably well. He recovered very quickly, was out of the Intensive Care Unit very shortly and he's actually within a day or two able to go home now. But this time in much better shape than he was before.
The trial aims to enroll 20 patients in total. Though rapid progress has been made as the first patient was done last week and the second a few days ago, the next 18 could take the rest of the year. The first two patients are “open label” meaning the doctor knows he’s put stem cells inside them. Dr. Yau will be blind to whether or not the rest receive stem cells, to maintain objectivity when evaluating patients’ hearts six months down the line.
Dr. Yau stresses that this effort is the result of a team of collaborators from surgery, cardiology, radiology, as well as stem cell experts from Princess Margaret Hospital that have contributed over many years.
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