July 8, 2013

Dear Friend of the Texas Heart Institute,

Look closely and you will find that a key to combatting cardiovascular disease requires just that – looking very closely. Looking down to the cellular and genetic levels, in fact, has led to some exciting discoveries and continues to do so.

That is how, for instance, we broke new ground just over a decade ago and learned that our own stem cells can be harnessed to regenerate and repair damage in our hearts. 

By looking even more closely, we also now know that as we age, our stem cells age along with us. That means both the number of stem cells our bodies produce and the cells' regenerative powers decline. This takes place even as our risk of developing cardiovascular disease increases. 

However, we are beginning to learn that we might be able to reverse that process and rejuvenate stem cells at a time when our aging bodies need them the most. Not quite the fountain of youth, but some tantalizing drops. 

I am proud to be part of a research team that has been examining this problem and has recently discovered that by overexpressing two genes in the stem cells of aged lab mice (with and without atherosclerosis) we were able to increase both the proliferation of the cells and the ability of the cells to generate new heart muscle tissue. 

The research findings have just been published in the prestigious American Heart Association journal Circulation Research. 

The team specifically examined the role of overexpression of myocardin and telomerase in stem cells from bone marrow and fat tissue in aged lab mice. These genes are involved in heart muscle regeneration and prevention of cellular deterioration, respectively. We believe these genes might act together to enhance cardiovascular regeneration and restore the aged cells to their youthful capacity. 

Our team also examined the effect of then transplanting these treated stem cells into mice with restricted blood flow (ischemia) in the hind limbs.  

The results were conclusive. Overexpression of myocardin and telomerase in the aged stem cells decreased cell death and increased cell proliferation and muscle tissue generation; that is, the aged stem cells regained their youthful capacity. Once injected with these rejuvenated stem cells, the mice with hind limb ischemia then showed increased blood flow and artery capacity to their legs. (Mice were used as cell therapy recipients due to the fact that they show similar development of atherosclerosis to humans.) 

Put simply, the conclusion is that overexpression and transplantation of these two genes may be therapeutic in rejuvenating aged stem cells. 

The research team included Dr. Rosalinda Madonna, Dr. Doris Taylor, Dr. Yong-Jian Geng, Dr. Raffaele De Caterina, Dr. Harnath Shelat, Dr. Emerson Perin, and myself.

There is more work to do, and we hope to begin testing this process in humans in the near future. But needless to say, we are excited about the possibilities and will continue looking very closely as we combat the ravages of cardiovascular disease together.  

Of course, we could not do it without your support, for which we are very grateful.

With respect and gratitude,

 
James T. Willerson, MD
President and Medical Director

Contact Dr. Willerson.