Joshua Hare from the Interdisciplinary Stem Cell Institute at the University of Miami Miller School of Medicine has headed up the POSEIDON clinical trial. Poseidon stands for the Percutaneous Stem Cell Injection Delivery Effects on Neomyogenesis Pilot Study (NCT01087996). The goal of this study was to examine the effects of mesenchymal stem cells on the hearts of patients who had suffered a heart attack some time ago and compare the effects of treating a patient with their own mesenchymal stem cells, or with those of a donor. Mesenchymal stem cells (MSCs) are known to not rile the immune system, but if they are implanted for a long period of time, there is a chance that they will elicit an immune response. However, there is evidence that the bone marrow quality of a patient decreases after a heart attack. Therefore, administering MSCs from a healthy donor might work even better than using a heart attack patient’s own MSCs.
In this trial, Hare and his colleagues took 31 patients who suffered from “ischemic cardiomyopathy,” and randomly gave them injections into their heart muscle of their own MSCs, or MSCs from a healthy donor. They monitored the patients for adverse effects and also monitored their heart function 1 year after MSC administration.
The results showed a low rate of adverse effects for both groups 30 days after treatment. One year after treatment, there were even fewer adverse effects. The patients who were given their own MSCs showed improvement over the distance walked in 6 minutes. These same patients also said that they had an increased quality of like. Both groups also showed some improvements in the remodeling of their hearts, which is the say that the enlargement of the heart was decreased. Unfortunately, there were no measurable improvements in heart function. Importantly, none of the patients who had received someone else’s MSCs showed a significant immune response against the implanted MSCs. One patient did show some antibodies against the implanted MSCs, but this is only 1/15 patients in the absence of any immunosuppression.
These results are modest, but they are good enough for a larger clinical trial. to that end, Hare will now engage in the ALLSTAR (Allogeneic Heart Stem Cells to Achieve Myocardial Regeneration) study (NCT01458405) of 270 patients with ventricular dysfunction after a heart attack. These results are reasons for cautious optimism.