First-ever stem cell treatment on a non-human primate a success

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Despite severe arthritis, KJ is hopping again at the Mesker Park Zoo and Botanic Garden in Evansville, Indiana.

The 17-year-old male colobus monkey has newfound mobility after receiving a stem cell treatment earlier this year from Dr. Val Johnson, a veterinarian and postdoctoral fellow at Colorado State University.

KJ is the first non-human primate treated with stem cells by CSU veterinarians. Based on a review of published research, Johnson said he is also the first non-human primate in the world to be treated therapeutically with stem cells for a naturally occurring disease.

In late 2019, KJ started to have trouble with his hind legs and was diagnosed with age-related spinal arthritis. Following a CT scan, his medical team learned that the arthritis was quite severe and likely affected some nerves and discs along his spine.

Enter Johnson, who has safely treated a giraffe, elephants, mountain lion, tiger, wolf, coyote and dogs with stem cells over the past eight years.

Dr. Carrie Ullmer, staff veterinarian at the Mesker Park Zoo, had heard about Johnson’s research and success with stem cell treatments.

“Dr. Ullmer reached out to me about KJ because they had tried just about everything, including the use of medications to treat pain and inflammation,” Johnson said. “Nothing had worked. He was very sore and he was not doing normal activities that monkeys do.”

Condition improved dramatically

To perform the procedure, Johnson first grew stem cells from a small piece of adipose, or fat, tissue from another colobus monkey at the zoo. This fat sample was then treated to grow mesenchymal stem cells, a type of cell that can help the body repair some inflamed or damaged tissues. Zookeepers monitored KJ’s behavior before, during and after treatment to see if the therapy helped his condition.

The verdict was “yes.” In addition to two stem cell treatments, KJ worked with a local chiropractor and received cold laser therapy at the zoo.

Johnson said the medical team described KJ’s improvement as “dramatic.”

“That’s awesome,” she said. “He’s now exhibiting behaviors that the zookeepers hadn’t seen in a long time, and we are very happy with the success.”

Johnson said these findings will be helpful for veterinarians and medical doctors who use stem cell therapy, though clinicians need to perform more of these treatments.

“Physicians have seen some good results in humans, but you have the placebo effect, so they are not always entirely sure if it was a success,” she said.

Non-human primates don’t have a placebo effect, and there are things about their behaviors that veterinarians can objectively measure, like whether they can hang from a branch or hop like KJ.

“Their anatomy is so much more akin to humans, so it’s a great area to explore,” said Johnson. “This type of research and veterinary care helps arthritic monkeys and translational medicine to humans.”


This story was adapted from an article written by Dr. Carrie Ullmer, staff veterinarian at the Mesker Park Zoo and Botanic Garden.