Cardiovascular diseases are the leading cause of death worldwide with a toll of over 17.9 million lives each year, according to the World Health Organisation.
A majority of the people with heart disease (about 14.4%) have coronary heart disease, a major cause of concern among researchers. Coronary heart disease is caused when the heart’s blood supply is blocked by fatty substances clogging the arteries that lead to the heart.
Researchers attribute the blockage of heart vessels to unhealthy lifestyles, poor diets, physical inactivity, tobacco use and consumption of harmful levels of alcohol.
Diseases like coronary heart disease don’t only block vessels but also damage cardiac tissue, leading to dysfunction and necrosis of cardiomyocytes, the special cells that make up the heart.
Humans are incapable of regrowing damaged heart tissue. Instead, the organ gets scar tissue or the person has to undergo a heart transplant, which comes with its own set of complications.
Now, a group of scientists, led by Rajkumar P. Thummer, assistant professor, Department of Biosciences & Bioengineering at the Indian Institute of Technology, Guwahati, has come up with a solution where healthy skin cells from an adult can be converted into heart cells using special proteins.
How does it work?
According to the scientists, converting cells from one form to another – a.k.a. cellular reprogramming – involves specific proteins, called transcription factors, that alter the “expression of genes within a cell and direct it to take on a new cellular identity”.
“In a damaged heart, the irreversible loss of beating cells leads to the formation of scar tissue containing cardiac fibroblast [a type of cells]. In the field of cardiology, balancing this loss of cardiomyocytes is highly challenging, even in this modern medical world,” Dr Thummer told The Hindu in an email.
“Therefore, our lab established a recombinant protein toolbox consisting of six potential cardiac transcription factors, which can convert these fibroblasts into functional cardiomyocytes.”
Dr Thummer said that the toolbox consists of six recombinant proteins: GATA4, MEF2C, TBX5, ETS2, MESP1, and HAND2. Each of these proteins plays a significant role in reprogramming fibroblasts – a type of cells that provides structure to tissue – into cardiomyocytes.
While there has been research to convert somatic cells (any cell of a living organism) into heart cells, this particular study aims to find a safer procedure.
“Fibroblasts are the most commonly used cell source for cellular reprogramming. The majority of the previous studies used an integrative approach based-cardiac reprogramming, which limits clinical applicability,” Dr Thummer said.
“Thus, we aimed to develop a safer approach for direct cardiac reprogramming, which can then be used to reprogram cardiac fibroblasts which form scar tissues after heart attack, into functional cardiomyocytes in the damaged heart.”
“Proteins are safer and necessary macromolecules in our diet. The advantage of recombinant proteins-based cell conversion is they work their miracle inside the nucleus and eventually disappear over time without leaving behind their toxic waste, unlike their genetic counterparts. Thus, they are very safe for reprogramming compared to other approaches,” he explained.
The research group has expressed an expectation that the study will help derive functional cardiomyocytes that are tailored to a patient’s needs along with increased efficiency in cellular reprogramming.