Dr Oren Caspi, from the Technion-Israel Institute of Technology has done some very interesting work with pluripotent stem cells and the heart. Recently, Caspi and his colleagues made induced pluripotent stem cells (iPSCs) from skin cells extracted from heart patients. These were differentiated into heart muscle cells that had all the characteristics of young, healthy heart tissue from new-born babies.
This has been done before in other labs (for one example, see Ma J., et al., Am J Physiol Heart Circ Physiol 2011 301(5):H2006-17). What Caspi and others found that was so remarkable was that these reprogrammed cells have the capacity to “reset” the rhythm of any unhealthy heart tissue that surrounds them. Caspi and others in the laboratory of Gepstein Lior think is that patients suffering from irregular or slow heart beats, who normally require a pacemaker, could, instead, be treated with an injection of new heart cells grown from stem cells made from their own cells to create a “biological pacemaker” that could regulate their heartbeat.
At this time, heart attack patients have hearts that pump out of sync or who suffer from irregular heartbeats. Such patients require surgery in order to insert a battery-powered pacemaker that is fitted to control the heart’s rhythm. There are approximately 25,000 pacemakers fitted each year in the United Kingdom alone.
According to Dr. Caspi, “We found that the electrical signal from the heart cells we created synchronized the beat of any surrounding heart tissue. We have seen this happen in dishes in the laboratory and in animal models. When we integrated the cells into the hearts of pigs, they were paced by the cells that were injected. It seems that the cells that beat fastest control the pace, so it could be used to replace artificial pacemakers for people with slow or irregular heartbeats.”
In May, 2012, Caspi and Gepstein became the first scientists in the world to make heart muscle cells from iPSCs that were made from heart patients. They reverted adult skin cells into iPSCs and then used special culture conditions to convert those cells into fully functioning heart cells. These cells integrated into the hearts of rats, and researchers believe that it will be possible to use skin cells from patients to create injectable biological pacemakers. This will reduce the risk of them being rejected by the patient’s body. They are now working with clinical heart specialists in a bid to design a human clinical trial that will evaluate the efficacy of such a treatment in human patients.
According to Caspi: “We are working with clinicians to take some of our data to the clinic, but it is still a very new technology so there is still a lot of research to be done before any treatments will emerge.”