Expanding Stem Cells: Finding the Most Efficient Way

Expanding Stem Cells: Finding the Most Efficient Way

Researchers are getting closer to determining the most efficient way to expand stem cells for use in horses.

Photo: The Horse Staff

One of the challenges that accompanies stem cell therapy is having enough cells for an effective treatment; in some scenarios treatment must wait several weeks for cell expansion before it can begin. The good news is that researchers are getting closer to determining the most efficient way to expand stem cells.

John Kisiday, PhD, assistant professor of equine orthopedics in the department of clinical sciences at the Colorado State University College of Veterinary Medicine and Biomedical Sciences, and a team recently set out to determine the most efficient way to expand adult bone marrow-derived stem cells.

Using six donor horses, Kisiday and colleagues harvested two 5 ml samples from one side of each horse's pelvis before aspirating a 50 ml sample from the other side of the pelvis. Additionally, two samples from each horse's sternum were harvested in a similar manner (i.e., two 5 ml samples followed by one 50 ml sample collected from two locations).

Key findings of the study included:

  • The first 5 ml fraction harvested from the pelvis had 3.5 times and 2.5 times higher density of nucleated cells relative to the second 5 ml and the 50 ml fraction, respectively;
  • Both of the 5 ml samples collected from the sternum had a twofold higher density of nucleated cells than the 50 ml sample;
  • After proliferation (i.e., cell growth), the first 5 ml sample yielded three times more cells than the second 5 ml sample and the 50 ml sample; and
  • In the laboratory model of cartilage repair, total GAG (glycosaminoglycans, molecules in cartilage help it resist compressive forces in the joint as a horse bears weight) accumulation was not significantly different between the samples.

"The most efficient isolation of mesenchymal stem cells (MSCs) is obtained from the first 5 ml of bone marrow aspirate," Kisiday concluded. "MSCs from all fractions are similar in terms of growth and differentiation potential."

In a second study, Kisiday and a team evaluated whether the concentration at which cells are proliferated has an impact on how they expand.

"We compared proliferation of adult MSCs in cultures seeded at high (10,000 cells/cm2) or low (500 cells/cm2) density over a 10-day time course," he explained.

Key findings included:

  • High density cultures resulted in 10.9 population doublings over the time course; and
  • Low density cultures experienced 14.1 population doublings over the same time period.

"Low density seeding of proliferation cultures are advantageous over high density cultures, as a higher rate of proliferation can be achieved," Kisiday concluded.

Combined, the two studies indicate that the first 5 ml of bone marrow retrieved from the horse proliferated in low density cultures appears to be the most efficient way for veterinarians to expand stem cells for use in injured horses.

"From a processing standpoint our guidelines ensure that we can obtain treatments in the quickest possible manner while limiting the number of times we have to 'handle' the cells, which results in a simpler process," Kisiday added.

About the Author

Erica Larson, News Editor

Erica Larson, News Editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in three-day eventing with her OTTB, Dorado, and enjoys photography in her spare time.

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