Jianyi Zhang, from the University of Minnesota Health Science Center, in Minneapolis, Minnesota and his co-workers have shown that the transplantation of human umbilical cord blood cells into the rat hearts after a heart attack experience long-term effects that are not observed in the control animals that did not receive the stem cells. Furthermore, none of these laboratory animals required immunosuppressive therapy. The study is scheduled to be published in the journal Cell Transplantation.
“Myocardial infarction induced by coronary artery disease is one of the major causes of heart attack,” said Dr. Zhang. “Because of the loss of viable myocardium after an MI, the heart works under elevated wall stress, which results in progressive myocardial hypertrophy and left ventricular dilation that leads to heart failure. We investigated the long-term effects of stem cell therapy using human non-hematopoietic umbilical cord blood stem cells (nh-UCBCs). These cells have previously exhibited neuro-restorative effects in a rodent model of ischemic brain injury in terms of improved LV function and myocardial fiber structure, the three-dimensional architecture of which make the heart an efficient pump.”
According to Zhang and his co-authors, stem cell researchers have intently examined the ability of stem cells to regenerate and heal damaged heart tissue. Many laboratories all over the world have employed different types of stem cells, different animal models, and distinct modes of stem cell delivery into the heart tissue, and different stem cell doses. All of these studies have produced varying levels of improvement of left ventricular function. Zhang and others also note that, for the most part, the underlying mechanisms by which implanted stem cells improve heart function are “poorly understood and that the overall regeneration of heart muscle cells is modest at best.
In order to investigate the heart’s remodeling processes and to characterize the alterations in cardiac fiber architecture, Zhang’s team used diffusion tensor MRI (DTMRI), which has been previously used to study heart muscle fiber structure in both humans and animals. Most previous studies have concentrated on the short-term effects of umbilical cord blood cells (UCBCs) on damaged heart muscles. Fortunately, this study, which examined the long-term effects of UCBCs, not only demonstrated evidence of significantly improved heart function in treated rats, but also showed evidence of delay and prevention of myocardial fiber structural remodeling. Keep in mind that such alterations in heart muscle fiber structure could have resulted in heart failure.
When compared to the age-matched but untreated rat hearts that had suffered a heart attack, the regional heart muscle function of non-hematopoietic UCBC-treated hearts was significantly improved and the preserved myocardial fiber structure seems to have served as an “underlying mechanism for the observed function improvements.”
“Our data demonstrate that nh-UCBC treatment preserves myocardial fiber structure that supports the improved LV regional and chamber function,” concluded the researchers.
“This study provides evidence that UCBCs could be a potential therapy with long-term benefits for MI” said Dr. Amit N. Patel, director of cardiovascular regenerative medicine at the University of Utah and section editor for Cell Transplantation. “Preservation of the myocardial fiber structure is an important step towards finding an effective therapy for MIs”
See: Chen, Y.; Ye, L.; Zhong, J.; Li, X.; Yan, C.; Chandler, M. P.; Calvin, S.; Xiao, F.; Negia, M.; Low, W. C.; Zhang, J.; Yu, X. The Structural Basis of Functional Improvement in Response to Human Umbilical Cord Blood Stem Cell Transplantation . Cell Transplant. Appeared or available online: December 10, 2013.