Bone Repair Via Stem-cell-growing Surface
May 24, 2012

Bone Repair Via Stem-cell-growing Surface

Connie K. Ho for

Technology is rapidly progressing and so is research related to stem cells.

Researchers from the University of Michigan recently announced that they found a special surface without biological contaminants that can help adult-derived stem cells to grow and change into different cell types. The findings, published in the journal Stem Cells, are considered a breakthrough in stem cell research.

In the study, scientists grew bone cells on the surface and then transplanted the cells to the skulls of mice to look at the cells´ regenerative powers. The results showed that the cells produced four times as much new bone growth in mice without the help of extra bone cells. The importance of these adult-derived “induced” stem cells is that they come from the patient and these cells are compatible for medical treatments.

"We turn back the clock, in a way. We're taking a specialized adult cell and genetically reprogramming it, so it behaves like a more primitive cell,” commented Paul Krebsbach, professor of biological and materials sciences at the U-M School of Dentistry, on the process of stem cell creation.

In the project, researchers examined how human skin cells are turned into stem cells and, even though they are not exactly sure as to how the process works, how it involves the addition of proteins that can signal the genes to turn on and off to the adult cells. Prior to being used to repair parts of the body, the stem cells are grown and directed to become a specific cell type. Researchers were able to use the surface of the animal cells and proteins for stem cell habitats, but saw that the amount of cells produced could vary by animal.

"You don't really know what's in there," noted Joerg Lahann, associate professor of chemical engineering and biomedical engineering.

One difficulty researchers have encountered in the past is the fact that human cells and animals cells can sometimes mix. However, the polymer gel made by Lahann and his fellow researchers helped avoid this problem. Researchers were able to gain better control over the gel´s ingredients and how they were combined.

"It's basically the ease of a plastic dish," Lahann said. "There is no biological contamination that could potentially influence your human stem cells."

With the project´s findings, the group was able to show how the surfaces could grow embryonic stem cells.

In step two of the study, Lahann worked with Krebsbach´s team to demonstrate how the polymer surface could aid the growth of more medically promising induced stem cells and continue to have them be in a high-potential state. The researchers changed the stem cells into fat, cartilage, and bone cell to demonstrate the cell´s ability to change into different types.

The researchers continued the project by experimenting to see if the cells could assist the body in making repairs and tested to see if the cells could fix five millimeter holes in the skulls of mice. Interestingly enough, the cells were able to fill in the hole over time. After eight weeks, the mice had bone cells that were 4.2 times new bone and the bone showed the roots of marrow cavities. As well, the extra bone growth was the result of added cells and the growth was made up of human bone.

"The concept is not specific to bone," Krebsbach said. "If we truly develop ways to grow these cells without mouse or animal products, eventually other scientists around the world could generate their tissue of interest."

In the future, Lahann´s team hopes to examine how to use the polymer gel to grow more stem cells, specifically cells that can specialize in different shapes.