Joshua Hare from the Interdisciplinary Stem Cell Institute at the University of Miami Miller School of Medicine in Miami, Florida has conducted a variety of high-quality clinical trials that have tested the ability of mesenchymal stem cells to heal the hearts of patients with ischemic heart disease. Two of these trials, (Transendocardial Autologous Cells in Ischemic Heart Failure) and POSEIDON (Percutaneous Stem Cell Injection Delivery Effects on Neomyogenesis), injected mesenchymal stem cells from bone marrow directly into damaged heart muscle.
Both of these studies not only showed an increase in heart function after injection of mesenchymal stem cells compared to placebo, but further examination showed that mesenchymal stem cells induced shrinkage of the heart scar and replacement with living heart muscle tissue (see Alan Heldman and others, Transendocardial Mesenchymal Stem Cells and Mononuclear Bone Marrow Cells for Ischemic Cardiomyopathy: The TAC-HFT Randomized Trial, JAMA, Published online November 18th 2013). However, Hare wanted to compare the benefits experienced by younger patients with older patients in order to determine if age had any effect on the efficacy of this treatment.
To that end, Hare and his colleagues compared subjects from the TAC-HFT and POSEIDON clinical trials in 2 age groups: younger than 60 and 60 years of age and older. They used a 6-min walk distance to measure heart function and the Minnesota Living With Heart Failure Questionnaire (MLHFQ) to ascertain the quality of life of each patient. Patients were tested at baseline (before the procedure), 6 months, and 1 year after the procedure. Hare and his group also used particular cardiac imaging measurements, such as absolute scar size and compared the baseline size of the heart scar, and then again 1 year after the procedure.
These two tests, the 6MWD and the MLHFQ showed improvements in both age groups. These improvements were even significant in both groups. What this analyses show is that mesenchymal stem cell therapy helps patients with ischemic heart failure, regardless of their age. Older individuals did not have an impaired response to MSC therapy.
This is an important result because heart disease is very often a condition of the aged and there are concerns as to whether or not older patients would benefit from regenerative medical procedures. Hare’s study suggests that older patients do benefit from these procedures. A caveat is that older patients have lower-quality mesenchymal stem cells, but these studies tended to use allogeneic mesenchymal stem cells or stem cells from donors. Therefore, allogeneic stem cell treatments may prove effective in older heart patients.