Using nanomaterials to regenerate damaged cardiac cells

Researchers from the National University of Ireland Galway (NUI Galway) and Trinity College Dublin (TCD) have exploited a commonly-used nanomaterial to produce cells capable of repairing cardiac muscle damaged by heart failure. The team combined adult stem cells with carbon nanotubes – nanomaterials which are reactive to electrical stimulation – to replicate the characteristics of special heart cells known as cardiac progenitors.

In conjunction with Professor Werner Blau from TCD's School of Physics, Drs Valerie Barron and Mary Murphy from NUI Galway’s Regenerative Medicine Institute (REMEDI) spearheaded this pioneering technique. In order to create their replica progenitors, the researchers, whose findings have been published in the journals Biomaterials and Macromolecular Bioscience, introduced carbon nanotubes into mesenchymal stem cells taken from human bone marrow.

In an interview with ScienceOmega.com, Dr Barron explained why it was necessary to take such a novel approach to cardiac repair.

"The cells that we are interested in are called cardiomyocytes and they are found in the cardiac muscle," she began. "An invasive operation is necessary in order to harvest these cells. This is not usually a clinical option, especially with patients who have undergone surgery in the wake of heart attacks. Whilst the procedure has been performed before, it is only appropriate in special cases.

"Cardiac progenitor cells are specialised stem cells capable of transforming into heart tissue," continued Dr Barron. "If you can identify a source from which large numbers of similar cells can be readily retrieved, you can transform those cells into cardiac progenitors. This is what we set out to achieve."

In order to turn mesenchymal stem cells into cardiac progenitors, the researchers introduced carbon nanotubes. It is the nanomaterial’s electrical conductivity which makes it so suitable for this transformative purpose.

"Cardiac muscle is an electroactive tissue," explained Dr Barron. "Mesenchymal stem cells can incorporate nanotubes because nanotubes are very, very small. They have nanometre dimensions whereas cells exist at the micron scale. Essentially, we were able to produce electroactive cells. When we applied electrical stimuli to these cells, they transformed into cardiac progenitors.

"We have demonstrated in the laboratory that this technique works. If we can show that the procedure is safe in the preclinical model, we will be able to begin preclinical trials. We must also concentrate on delivery, tracking and implementation. Our next task is to decide upon the best method for introducing the modified cells into a patient. We could inject them into the coronary artery, we could inject them directly into the damaged muscle, or we could use a patch to introduce the cells."

Whilst this approach could significantly benefit patients recovering from heart failure, its potential applications are not limited to the field of cardiology. I concluded our conversation by asking about the other electroactive tissue repair applications that might result from Dr Barron’s research.

"The spine," she replied. "People who have been involved in serious car crashes often suffer severe spinal injuries. The spinal cord is another electroactive tissue which allows electrical signals to be transmitted throughout the body. Patients with really bad spinal injuries are often left without sensory or mechanical function. Our research could be used to help these people. The brain represents another potential field of application due to its electroactive nature. There are several areas in which we might be able to apply the technique that we have developed."