Just like all cells, tissues, and organs in the body, stem cells also age as a person grows older. Now scientists have developed a technique to rejuvenate aging stem cells and allow them to function like their younger, more robust versions. This method of transforming old stem cells into new has applications in the treatment of diseased and damaged hearts in the elderly.
Stem cells obtained from the bone marrow of donors are at risk of being rejected by the recipient, but stem cells from the patient themselves can repair damaged tissue in the body without being rejected. The problem with elderly patients is that using their own stem cells has not been a feasible alternative so far because aging cells do not function as well as the stem cells of younger people.
Milica Radisic of the University of Toronto’s Department of Chemical Engineering and Applied Chemistry, and also the Canada Research Chair in Functional Cardiovascular Tissue Engineering at the Institute of Biomaterials and Biomedical Engineering (IBBME), has worked with Dr. Ren-Ke Li, a co-researcher, to create conditions in tissue culture that function essentially like a fountain of youth, rejuvenating aging stem cells and transforming them.
The scientists have created an environment in the laboratory to grow heart tissue derived from stem cells which have been sourced from elderly donors at a large hospital in Toronto. The stem cells are positioned on porous scaffolding and then growth factors that stimulate the growth of blood vessels (angiogenesis) and proliferation of cells are infused into this cell culture.
Radisic and Li have studied the cells and tracked the changes occurring in them on a molecular level. Some aging factors were noted to be turned off, and two molecules, RGN and p16, were noted to reverse the aging of stem cells, converting them to a healthier and younger state.
Elderly and frail people with aneurysms (localized bulges in the walls of blood vessels) are not candidates for surgical repair, because the risks of surgery outweigh the benefits. Non-surgical therapy for aneurysms consists of strict blood pressure control to contain the expansion of the aneurysm. Among other applications, this new technique of rejuvenating aging stem cells will offer hope to elderly patients with large, life-threatening aneurysms. It will be possible to create healthy tissue to mend defects like aneurysms or reverse damage to the heart muscle which is the result of heart attacks.
Radisic, who was also a winner of the Top Innovators Under 35 award by MIT in 2008 and the Young Engineers Canada award in 2012, is excited by the possibilities. The study, published in the Journal of the ACC (American College of Cardiology), is being hailed as groundbreaking research and a new frontier in stem cell biology for cardiovascular diseases.
There are practical implications that need to be addressed before successful clinical application of the technique. Repairing a damaged heart will potentially require millions of cells, and generating a sufficient number of heart muscle cells from adult stem cells outside the human body to meet this demand is the challenge researchers must now address.
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