Stem Cell-Based Cartilage Regeneration Could Decrease Knee and Hip Replacements

Work by Chul-Won Ha, director of the Stem Cell and Regenerative Medicine Institute at Samsung Medical Center and his colleagues illustrates the how stem cell treatments might help regrow cartilage in patients with osteoarthritis or have suffered from severe hip or knee injuries.

A 2011 report from the American Academy of Orthopedic Surgeons showed that approximately one million patients in the US alone (645,000 hips and 300,000 knees) have had joint replacements in the U.S. alone. Most joint replacements occur with few complications, artificial joints can only last for a certain period of time and some will even eventually require replacement. Also these procedures require extensive rehabilitation and are, in general, quite painful. A goal for regenerative medicine is the regenerate the cartilage that was worn away to prevent bones from eroding each other and obviate the need for artificial joint replacement procedures.

Extensive research from the past two decades from a whole host of laboratories in the United States, Europe, and Japan have shown that mesenchymal stem cells (MSCs) have the ability to make cartilage, and might even have the capability to regenerate cartilage in the joint of a living organism. MSCs have the added benefit of suppressing inflammation, which is a major contributor to the pathology of osteoporosis. Additionally, MSCs are also relatively easy to isolate from tissues and store.

“Over the past several years, we have been investigating the regeneration potential of human umbilical cord blood- derived MSCs in a hyaluronic acid (HA) hydrogel composite. This has shown remarkable results for cartilage regeneration in rat and rabbit models. In this latest study we wanted to evaluate how this same cell/HA mixture would perform in larger animals,” said Ha.

Ha collaborated with researchers from Ajou University, which is also in Seoul, and Jeju University in Jeju, Korea. Ha and his team used pigs as their model system, which is a better system than rodents for such research.

The stem cells for this project were isolated from human umbilical cord blood that was obtained from a cord blood bank. They isolated MSCs from the umbilical cord blood and grew them in culture to establish three different human Umbilical Cord Blood MSC lines. Then they pelleted the cells and mixed them with the HA solution and applied them to the damaged knee joints of pigs.

“After 12 weeks, there was no evidence of abnormal findings suggesting rejection or infection in any of the six treated pigs. The surface of the defect site in the transplanted knees was relatively smooth and had similar coloration and microscopic findings as the surrounding normal cartilage, compared to the knees of a control group of animals that received no cells. The borderline of the defect was less distinct, too,” said the study’s lead investigator, Yong-Beom Park, who is a colleague of Ha’s at the SungKyunKwan University’s Stem Cell and Regenerative Medicine Institute.

“This led us to conclude that the transplantation of hUCB-MSCs and 4 percent HA hydrogel shows superior cartilage regeneration, regardless of the species. These consistent results in animals may be a stepping stone to a human clinical trial in the future,” Dr. Ha noted.

“These cells are easy to obtain, can be stored in advance and the number of potential donors is high,” said Anthony Atala, M.D., Editor of STEM CELLS Translational Medicine and Director of the Wake Forest Institute for Regenerative Medicine. “The positive results in multiple species, including the first study of this treatment in large animals, are certainly promising for the many patients requiring treatments for worn and damaged cartilage.”