Heart can Regenerate: Indian Doc
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03 April 2009
By Vithal C Nadkarni
A broken heart can mend itself, literally. In a discovery that opens up possibilities of helping people with serious cardiac ailments, an international team of researchers that included a Canadian–born Indian neurosurgeon has found that the heart can regenerate itself.
Scientists hitherto believed that the heart never regenerates. “We have shown for the first time that the heart is capable of regeneration,” Dr Ratan Bhardwaj – who gave primary inputs for the research under lab supervision of Jonas Frisen at Stockholm’s Nobel Medical Research Institute – told TOI just after the research paper was published in the prestigious journal, Science.
Bhardwaj, now at the University of Toronto, said the cells that regenerate, called cardiomyocytes, comprise 20% of the total heart tissue. They are also responsible for the crucial pumping action.
Calling the finding a “Myth breaker and a paradigm shifter in science”, Bhardwaj said it opens doors to future stem cell therapeutics and regenerative strategies. “It would be great if researchers could understand this mechanism better and possibly devise a pill to boost the regeneration of the organ especially after a heart attack or chronic heart failure,” he said.
The 35–year–old doctor said, “You are actually having your own body heal itself. It’s akin to the skin healing after a cut or the bones joining after a fracture. So wouldn’t it be great to find a way to heal your heart when it literally breaks, or fails? That’s the beauty of this experiment.”
The research used carbon dating to track DNA molecules within heart cells to show that new cells were being produced. “For the first time, we were able to see and show that the heart actually is continuously making and replenishing new heart cells.” Radio carbon dating is a technique used to determine the age of anything from the bust of the Mohenjodaro Priest to that of Queen Nefertiti. “But the body uses the same isotope, Carbon–14, in a very different way,” Bhardwaj explained.
Regeneration of heart expensive
During the Cold War, the rash of nuke–testing released huge amounts of radioactive C–14 in the atmosphere. This got mixed up with carbon dioxide in the atmosphere that plants used up in photosynthesis. “Humans and animals ate the plants; so the C–14 went into our system. Now could this somehow be tracked, we wondered. With that leap of logic, we zeroed in on the DNA molecule which ought to be fixed from the time when the cell was made, barring very negligible amounts of turnover, so if one could carbon date the DNA from a specific set of cells, one could find out how old that cell was,” Bhardwaj said.
“In terms of actually doing it, however, it was a long shot, very expensive. Not a lot of groups are able to do this: start with a whole human heart, separate the heart cells – the crucial 20% – from the rest; purify the DNA; send to lab to measure the C 14 content. One speck of dust in the sample can totally wreck the data. So we were not too worried about competing with many other labs,” he said.
The beating heart that’s responsible for pumping blood is made up of cardiomyocytes which comprise about 20% of the cells. The rest are largely support cells of the matrix. Bhardwaj said, “Now, as we grow in age and size, this amazing cell has long been known to ‘Hypertrophy’, that is, get bigger with function. We were able to show that it grows in number as well.”