Jury is in on cartilage formation

A diagram describing loading and unloading.

Hydrostatic pressure, similar to the forces created when one walks, is key to forming cartilage in joints. Photo courtesy of Elizabeth Loboa.

The jury had been out for years on the best environment for cartilage tissue engineering. Some studies suggested that the use of microgravity bioreactors, which approximate a zero-gravity environment, are the way to go, while others believe that bioreactors that approximate the effects of hydrostatic pressure, similar to the forces created when one walks, are key.

After years of competing theories, the jury is finally in.

MU Engineering Dean and Bioengineering Professor Elizabeth Loboa and her research team from the universities of North Carolina State and University of North Carolina, Chapel Hill concluded that the hydrostatic pressure method was the preferred method in their recent paper, “Comparison of Simulated Microgravity and Hydrostatic Pressure for Chondrogenesis of hASC,” published in Aerospace Medicine and Human Performance.

“Some studies suggest that microgravity bioreactors are ideal for the process to take place, while others show that bioreactors that mimic the hydrostatic pressure needed to produce cartilage might be more ideal. Our first-of-its-kind study was designed to test both theories,” Loboa explained.

Cartilage tissue does not regenerate once lost, so to replace it, scientists often use bioreactors or other devices that support tissue and cell development, which cause certain cells to begin the process of becoming cartilage. Figuring out the best environment for these cells to undergo that process is critical.

The study — funded by the National Space Biomedical Research Institute through NASA, the National Institutes of Health, and the National Science Foundation — compared both methods through a series of experiments using human adipose derived stem cells (hASC), or stem cells in fat. The results showed that cyclic hydrostatic pressure caused three times greater chondrogenic differentiation — the process through which cartilage is produced — and created stronger tissues. Microgravity, meanwhile, decreased production.

“The study also shows that microgravity, which is experienced in space and is similar to patients on prolonged bed rest or those who are paralyzed, may inhibit cartilage and bone formation. Bioengineers and flight surgeons involved with astronauts’ health should consider this as they make decisions for regenerating cartilage in patients and during space travel,” Loboa said.

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