This week, in the Nature journal, Dr. Charles Murry’s team at Washington University (Seattle) published the results of recent experiments on Macaque monkeys having undergone heart attacks. The scientists used cardiomyocytes (cardiac muscle cells) derived from human embryo stem cells (HESC).
“The scientists initially devised a protocol to generate billions of cardiomyocytes from a pre-established HESC line”. They then triggered “minor” heart attacks in Macaque monkeys. Two weeks later, they injected the cardiomyocytes into the affected areas. The Macaque monkeys were euthanized and the scientists were able to draw their conclusions from this experiment. The fact that no tumours were detected – the main risk involved in handling HESC – was viewed as an “encouraging” sign. “However, given the short lifespan of the Macaque monkeys following transplantation, it is impossible to say whether or not tumours would have subsequently developed”. Conversely, 10% of the infested cells that survived could be differentiated correctly and vascularised.
At the same time, the problems encountered put the successes into perspective. In fact, “all of the monkeys treated with these cells presented with arrhythmias (abnormal heart beats)”. Furthermore, “it is impossible to confirm any improvement in cardiac tissue recovery given the absence of a control group”.
The therapeutic solution for man is apparently still a long way off at the present time.