US scientists have just achieved something pretty remarkable, regenerating parts of a human heart by using skin stem cells.
In news that leads us down the road to self-repairing human hearts, scientists at Massachusetts General Hospital (MGH) have just shown how skin cells could help regenerate damaged heart tissue.
Using stem cells created from human skin, Harald Ott and his colleagues successfully took a donor heart and stripped it of pretty much everything but its external structure.
Then, they induced the heart with “induced pluripotent stem cells” (IPSCs) from the skin cells, with the subsequent regeneration paving the way for patients with damaged hearts no longer having to rely on exact match donors.
Keep the matrix
The whole heart cannot be created this way, with the structural matrix required as a type of scaffold. So the team worked with dozens of real human hearts, stripping them of their living tissue components and finding a solution that’s quite effective.
“Generating functional cardiac tissue involves meeting several challenges,” said MGH’s Jacques Guyette, lead author of the report.
“These include providing a structural scaffold that is able to support cardiac function, a supply of specialised cardiac cells, and a supportive environment in which cells can repopulate the scaffold to form mature tissue capable of handling complex cardiac functions.”
Instead of using genetic manipulation to generate iPSCs from adult cells, the team used a newer method to reprogram skin cells with messenger RNA factors, which should be both more efficient and less likely to run into regulatory hurdles.
A partially recellularised human whole-heart cardiac scaffold, reseeded with human cardiomyocytes derived from induced pluripotent stem cells, being cultured in a bioreactor that delivers a nutrient solution and replicates some of the environmental conditions around a living heart. Image via Bernhard Jank, MD, Ott Lab, Center for Regenerative Medicine, Massachusetts General Hospital
Repopulation
The research team is led by Harald Ott, who developed a way of stripping living cells from organs with a solution and repopulating the cells with stem cells as far back as 2008.
Since then, his team has used the approach to generate functional rat kidneys and lungs and has decellularised large-animal hearts, lungs and kidneys. This human heart experiment, though, is a first.
It is not quite clear if donor recipients could, in theory, take any heart – already stripped of its living cells – and have their own skin cells help regenerate the missing components. Or if their own damaged hearts could be repaired of any issue. But the studies are ongoing.
While regenerating the entire heart, scaffolding and all, remains several years away, the MGE team are currently working on creating a “functional myocardial patch” that could be introduced to replace damaged heart tissue.
Many steps ahead
“Among the next steps that we are pursuing are improving methods to generate even more cardiac cells – recellularising a whole heart would take tens of billions – optimising bioreactor-based culture techniques to improve the maturation and function of engineered cardiac tissue, and electronically integrating regenerated tissue to function within the recipient’s heart,” said Guyette.
Stem cell research is thriving at the moment. For example, last year we spoke with Cathal O’Connell, an Irish 3D bioprinting researcher who is working on a ‘pen’ for surgeons to draw stem cells onto injured knees during surgery.
There are also researchers developing ‘mini brains’ from human cells that could, in theory, replace animals in laboratory testing, too. The size of the eye of a housefly – which means a speck of dust, barely visible – hundreds of thousands of copies can be created in one go.
Main heart image via Shutterstock
