Stem Cell Therapy Partially, Unreliably Repairs Spinal Cord Injuries in Rats
Engineering regeneration of an injured spinal cord is one of the fields to watch as a marker of capabilities in stem cell medicine. There is a fair amount of funding and effort directed towards this goal, and it requires overcoming a number of issues that are relevant to other types of regenerative medicine. These include overcoming scarring, inducing healing in tissues that normally do not regenerate in adults, ensuring the reliability of the outcome, and so forth. As the study here indicates, reliability remains a challenge. In all stem cell therapies, the factors that affect patient outcomes are still poorly understood.
Engineered tissue containing human stem cells has allowed paraplegic rats to walk independently and regain sensory perception. The implanted rats also show some degree of healing in their spinal cords. Spinal cord injuries often lead to paraplegia. Achieving substantial recovery following a complete spinal cord tear, or transection, is an as-yet unmet challenge. The researchers implanted human stem cells into rats with a complete spinal cord transection. The stem cells, which were derived from the membrane lining of the mouth, were induced to differentiate into support cells that secrete factors for neural growth and survival.
The work involved more than simply inserting stem cells at various intervals along the spinal cord. The research team also built a three-dimensional scaffold that provided an environment in which the stem cells could attach, grow and differentiate into support cells. This engineered tissue was also seeded with human thrombin and fibrinogen, which served to stabilize and support neurons in the rat's spinal cord.
Rats treated with the engineered tissue containing stem cells showed higher motor and sensory recovery compared to control rats. Three weeks after introduction of the stem cells, 42% of the implanted paraplegic rats showed a markedly improved ability to support weight on their hind limbs and walk. 75% of the treated rats also responded to gross stimuli to the hind limbs and tail. In addition, the lesions in the spinal cords of the treated rats subsided to some extent. This indicates that their spinal cords were healing. In contrast, control paraplegic rats that did not receive stem cells showed no improved mobility or sensory responses. While the results are promising, the technique did not work for all implanted rats. An important area for further research will be to determine why stem cell implantation worked in some cases but not others.
Link: https://www.eurekalert.org/pub_releases/2017-11/f-prw111617.php