SOME NEW FINDINGS REGARDING STEM CELLS AND THE HEART

We all remember the enthusiasm with stem cell therapy in the early part of this decade. In the last few years, the enthusiasm has settled to a more sober and realistic expectation. This is partly the result of President Bush's decision not to fund embryonic stem cell research, and partly from the fact that many initial small scale studies have not shown much good, while others did. These mixed outcomes in some way, speaks of the diverse nature in which stem cells can react, in a given tissue environment. To get the same host conditions, with the same insults at the cellular level, to trigger the same stem cell reaction (in a predictable way), has proven to be a great challenge.

The 27th Feb issue of the Journal of the American Medical Association, carried an article by Dr Richard Burt of North Western, Chicago, on the beneficial effects of stem cell, and LV function improvement. Dr Burt has done electronic database research, or basically a meta-analysis of available clinical data on 17 clinical studies on acute coronary syndrome patients and 16 chronic CAD patients with poor LV, to see if the stem cells given to these patients had any benefit. It is important to remind ourselves that this is not a randomised control trial, and is possible the worse possible patient diverse groups to meta-analyse. Well he and his fellow researches did, and they even managed to convince the editorial board of JAMA to publish it (did not speak well of the JAMA editorial board). To cut a long story short, they found some small ( 2-5% ) LV function improvement, if those patients given stem cell therapy. They concluded that though the benefits are modest at best, it was clinical relevant, for these patients.

I must say that I will view this conclusion with a very, very large pinch of salt. However, I thought that I will take this opportunity to say a few words about stem cell therapy and myocardial rejuvenation. It is true that this line of treatment holds a very promising future. The potentials are tremendous. However, realizing the potential of stem cells, has proven to be a great challenge. First of all, embryonic stem cells (probably the best form of stem cells to use) is shrouded in controversies, ethical, moral and the rest of it. President Bush's decision not to use Federal funding for embryonic stem cell research, merely means that most of these embryonic stem cell research is now done overseas in Europe, Asia, including Taiwan, Hong Kong, Korea, Japan and Singapore. In a way, good for us. Then there is the possibility to use tissue stem cells from skin, blood, fibroblast, and the like, to stimulate them to different cell lines. This has also proven possible, but still needs much more work. It is true that up to date, the overall cardiac view seem to be that stem cells does enhance LV function in certain subgroups of patients, especially in those with ischemic to necrotic myocardium. The stem cells seem to be able to rejuvenate ischemic stem cells fairly predictably, but not so, old infarcted regions. The data on chronic infarcted LV function improvement has proven disappointing. Then again, there is the issue of side effects. It appears that those patients with the greatest potential to benefit (those with ischemic to necrosis myocardium) also has the greatest potential to sides effects, including troublesome arrthymias. Obviously, I must conclude by with a word of caution, Stem cell therapy for improvement of LV function still need much more research and is no where near ready for primetime. Those who are using it empirically (and I hear that some local cardiologist are giving to their patients post PCI), should warn their patients of the very controversial potential benefits and the great danger of harm. But then again, those who are using it are not believers of evidence base medicine to start with, and so they are unlikely to "play by the rules".