For the first time ever, scientists have genetically transformed skin cells from heart failure patients into healthy, beating, "young" heart tissue. This is a fantastic achievement for the field of regenerative medicine.
"We have shown that it's possible to take skin cells from an elderly patient with advanced heart failure and end up with his own beating cells in a laboratory dish that are healthy and young — the equivalent to the stage of his heart cells when he was just born," said the Technion-Israel Institute of Technology's Lior Gepstein, who led the study, in a release.
The transformation was achieved by guiding the skin cells from two men with heart failure — one 51, the other 61 — through an intermediate form known as human induced pluripotent stem cells, or "hiPSCs" for short. You can think of hiPSCs a little like unsculpted silly putty; like embryonic stem cells, hiPSCs can develop into just about any type of cell in your body.
Unlike embryonic stem cells, however, hiPSCs start out as fully-formed cells of a specific type. In the case of Gepstein's research, the hiPSCs started out as fully developed skin cells; the cellular silly putty had already been squished into a designated shape and function. By triggering the expression of a specific set of genes, Gepstein and his colleagues reprogrammed these cells into their hiPSC-form, rolling the silly putty back into a ball, as it were. Gepstein and his colleagues showed that these hiPSCs could then be coaxed into becoming heart muscle cells.
When Gepstein's team grew their new muscle cells in a dish, in the company of existing heart tissue, the two were beating in unison within a matter of days. When they transplanted the tissue into the hearts of rats, they observed the same thing.
"What was interesting was the cells could integrate with the rat tissue and contract in synchrony," Gepstein told the Guardian. "If you put the cells in and they beat with a completely different timing, you wouldn't see any improvement in heart function and may even cause a dangerous arrhythmia."
The team's results bring with them all the implications we've come to expect of stem-cell therapy. Tissues regenerated from a person's own cells are often described as "patient-specific," and are less likely to be rejected by that patient's immune system.
What's most exciting about this research, however, is that the heart cells derived from the skin cells of the two elderly patients appear to function just as well as those derived from young, healthy volunteers. Researchers have achieved the latter before, but, generally speaking, regenerating cardiac tissue would find more applications in the elderly. More and more people are surviving heart attacks. When they do, it leaves their hearts in a damaged state. By seeding these damaged hearts with healthy tissue, it could keep them pumping for years longer than they might otherwise be capable of.
That's still a ways off, however. Experts in cardiac and regenerative medicine interviewed by Reuters demonstrated the industry-standard cautious optimism:
"This is an interesting paper, but very early and it's really important for patients that the promise of such a technique is not over-sold," explained John Martin, a professor of cardiovascular medicine at University College London.
"The chances of translation are slim and if it does work it would take around 15 years to come to clinic."
The researchers' findings are published in the latest issue of the European Heart Journal.