A way to prevent a horse’s immune system attacking stem cells introduced for healing may have been found by US researchers.
The team at the University of Georgia used platelet lysate as a culture medium, rather than the typically used fetal bovine serum (FBS) for the culture of mesenchymal stem cells (MSCs). The latter can sometimes trigger unwanted immune responses in patients, said lead researcher Dr John Peroni, “essentially killing off the product intended to promote healing”.
Platelet lysate is the liquid that is obtained from blood platelets after freeze/thaw cycle(s). The freeze/thaw cycle causes the platelets to lyse, releasing a large quantity of growth factors necessary for cell expansion.
In a study funded by the Morris Animal Foundation, Peroni and his team found that using the platelet lysate as a culture medium with the goal of generating more immunologically compatible stem cells worked equally well when compared to a traditional culture medium, and may improve health outcomes when stem cell therapy is prescribed for equine patients.
Findings from their study recently were published in Stem Cell Research & Therapy.
“Many laboratories use fetal bovine serum (FBS) for the culture of mesenchymal stem cells (MSCs) since it is a great source of growth factors and nutrients,” Peroni said.
“However, MSCs expanded in FBS can sometimes trigger unwanted immune responses in patients, essentially killing off the product intended to promote healing.”
Peroni said that using growth factors derived from the same species being treated, in this case horses, would allow veterinarians to apply and better evaluate the clinical outcomes of MSCs by avoiding adverse reactions related to the use of FBS.
Dr Kelly Diehl, Senior Scientific and Communications Adviser at Morris Animal Foundation, said veterinarians had been using stem cell therapies to treat equine and small animal patients for more than a decade, but many questions remain. “One concern is how to best improve treatment success by making sure the immune system doesn’t destroy the introduced cells nullifying the treatment.
“Dr Peroni and his team may have found a viable solution using platelet lysate derived from horses as the culture medium to avoid this potential problem and improve stem-cell based treatments for horses.”
During the study, the University of Georgia team successfully produced platelet lysate from donor horses and used this substance as the sole media supplement for the culture expansion of equine bone marrow derived MSCs. They found platelet lysate did not alter the appearance and function of the equine stem cells or their ability to interact with other cell types, especially those found at injury sites, the target for regenerative therapies. The next step is to ensure that MSCs developed in lysate function appropriately in a preclinical setting, making sure they divide into tissues and control inflammation to promote healing.
Stem cell therapies have the potential to improve the outcome of potentially severe and life-ending musculoskeletal injuries in horses. The findings of this study have been encouraging and Peroni believes the same approach may one day be used to benefit other animals, including dogs and cats.