New synthetic stem cells may offer therapeutic benefits

Scientists have developed a synthetic version of a cardiac stem cell that may offer therapeutic benefits comparable to those from natural ones and reduce some of the risks associated with stem cell therapies.
The cells have better preservation stability and the technology is generalisable to other types of stem cells.
Stem cell therapies work by promoting endogenous repair; that is, they aid damaged tissue in repairing itself by secreting "paracrine factors," including proteins and genetic materials.
While stem cell therapies can be effective, they are also associated with some risks of both tumor growth and immune rejection.
Also, the cells themselves are very fragile, requiring careful storage and a multi-step process of typing and characterisation before they can be used.

Researchers from the University of North Carolina at Chapel Hill in the US and First Affiliated Hospital of Zhengzhou University in the China fabricated a cell-mimicking microparticle (CMMP) from polylactic-co-glycolic acid (PLGA), a biodegradable and biocompatible polymer.

The researchers then harvested growth factor proteins from cultured human cardiac stem cells and added them to the PLGA. Finally, they coated the particle with cardiac stem cell membrane.
"We took the cargo and the shell of the stem cell and packaged it into a biodegradable particle," said Ke Cheng, associate professor at NC State University.
When tested in vitro, both the CMMP and cardiac stem cell promoted the growth of cardiac muscle cells.

They also tested the CMMP in a mouse model with myocardial infarction, and found that its ability to bind to cardiac tissue and promote growth after a heart attack was comparable to that of cardiac stem cells.
Due to its structure, CMMP cannot replicate - reducing the risk of tumor formation.
"The synthetic cells operate much the same way a deactivated vaccine works," Cheng said.
"Their membranes allow them to bypass the immune response, bind to cardiac tissue, release the growth factors and generate repair, but they cannot amplify by themselves. So you get the benefits of stem cell therapy without risks," he said.

The synthetic stem cells are much more durable than human stem cells, and can tolerate harsh freezing and thawing. They also don't have to be derived from the patient's own cells.
The manufacturing process can be used with any type of stem cell, researchers said.
"We are hoping that this may be a first step toward a truly off-the-shelf stem cell product that would enable people to receive beneficial stem cell therapies when they're needed, without costly delays," Cheng said.