Researchers have stumbled upon a new type of cell that serves to heal a damaged heart – a discovery that could change the standard protocols of open-heart surgery.
University of Calgary researchers discovered the previously unidentified cell population in the pericardial fluid found inside the sac around the injured heart of a mouse.
The cell, a Gata6+ pericardial cavity macrophage, was seen to help heal the injury.
Helper cells surrounded the heat during a heart attack
The study’s lead author and University of Calgary post-doctoral fellow Justin Deniset told CBC, Canada’s public broadcaster, the scientists found these healing cells by injecting an extra gene into the mice that made immune cells appear fluorescent green.
Tracking the cells using a microscope, they saw the bright green illuminated spots surround the heart during a heart attack.
These cells helped reduce scarring “and helped the heart function more”, he said.
Do humans have this heart-healing capability?
The researchers, including a cardiac surgeon, went looking – and found – the same cells within the pericardium of people with injured hearts, confirming that the repair cells offer the promise of a new therapy for patients with heart disease.
Oddly enough, these same helpful cells tend to be sucked out and discarded during heart surgery – meaning an ally in recovery from major surgery routinely goes to waste.
The pericardium is the sac of fibrous tissue that surrounds the heart and the roots of the great blood vessels.
The pericardium’s outer coat is tough and thickened, loosely cloaks the heart, and is attached to the central part of the diaphragm and the back of the breastbone.
Its inner coat is double layered, with one layer closely adherent to the heart and the other lining the inner surface of the outer coat. The intervening space between these layers is filled with pericardial fluid.
This small amount of fluid acts as a lubricant to allow normal heart movement within the chest.
But the healing cells are routinely suctioned out as surgeons cut their way through the pericardium to the work on heart proper.
According to a statement from the University of Calgary, heart doctors had never before explored the possibility that cells just outside the heart could participate in healing and repair of hearts after injury.
Heart wasn’t thought to have self-healing abilities
Unlike other organs, the heart has a very limited capacity to repair itself, which is partly why heart disease is a leading cause of death.
“Our discovery of a new cell that can help heal injured heart muscle will open the door to new therapies and hope for the millions of people who suffer from heart disease,” said Dr Paul Fedak, a professor in the Department of Cardiac Sciences.
“We always knew that the heart sits inside a sac filled with a strange fluid. Now we know that this pericardial fluid is rich with healing cells.
“These cells may hold the secret to repair and regeneration of new heart muscle. The possibilities for further discovery and innovative new therapies are exciting and important.”
Dr Fedak hopes to move the research to a broader study of human heart repair – and how these healing cells seem to prevent heart muscle from abnormally thickening and stiffening, a condition called fibrosis that raises the risk of heart failure.
Meanwhile, there’s the job of alerting heart surgeons the world over – don’t throw out the pericardium or its precious liquid.