A protein in human bone marrow may be able to drive stem cells to repair a patient's blood system after an injury, according to a two-year study recently published in the Journal of Clinical Investigation. This new discovery might help make radiation and chemotherapy treatments more effective for cancer patients.

Scientists from UCLA's Jonsson Comprehensive Cancer Center found out that certain cells that make up the lining of blood vessels in bone marrow instruct hematopoietic stem cells (HSCs) – cells that can transform into any other type of blood cell – on how to fix themselves.

The scientists came up with a theory that the blood system will benefit after an injury when the activities that occur in bone marrow cause HSCs to accelerate recovery.
For the new study, the scientists used their prior research to identify a new protein called pleiotrophin (PTN). They found out that the process that initiates the recovery of blood stem cells and the entire blood system after an injury is when PTN binds to HSCs.

They decided to conduct mouse experiments in which the mice received a normal radiation dose and then were injected with PTN. They found that HSCs and the blood system healed more quickly and two thirds of the mice survived.

Furthermore, when the scientists withheld PTN in another experiment, they found that there was no advantage in the recovery of the blood stem cells.

The scientists are hoping that the success they've had with PTN in animal models will translate to human patients. "If PTN works as a systemic therapy for patients undergoing stem cell transplantation or receiving chemotherapy, this could potentially improve the quality of life of patients undergoing these treatments, shorten hospital stays, decrease infections and allow the anti-cancer treatments to potentially work more effectively," Dr. John Chute, lead investigator of the study and hematology and radiation oncology professor at UCLA, wrote to DOTmed News.

Right now, the scientists are hoping to apply for an investigational new drug approval from the FDA for a Phase I clinical trial. They're planning on treating cancer patients who received chemotherapy with PIN, on a daily basis from the time they complete chemotherapy to the time their blood counts recover.

"We hypothesize that PTN treatment will make the blood counts recover more quickly, and we hope to avoid any meaningful toxicities in the Phase I trial," wrote Chute.

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