Reducing the Risk of Rejection
Posted on December 27, 2018
A new study by researchers at Columbia University suggests that the human intestine could provide up to 10 percent of blood cells in circulation in the body from its own private stash of blood-forming stem cells.
The results of the study conducted by the Vagelos College of Physicians and Surgeons are groundbreaking; researchers have previously believed that all blood cells were created solely in the bone marrow from hematopoietic stem cells.
Hematopoietic stem cells are the stem cells that mature into blood cells.
What Are the Impacts of This Discovery?
One of the most significant impacts of this discovery is its benefit for individuals living with Crohn’s disease and other bowel conditions that do not currently have a cure.
Crohn’s disease is an inflammatory bowel disease marked by painful inflammation. According to the U.S. Centers for Disease Control and Prevention, Crohn’s affects about 780,000 Americans.
Conventional treatments for these illnesses often include medications, including both steroids and nonsteroidal anti-inflammatories, as well as antibiotics and vitamins.
“For many people, the treatments for Crohn’s disease and other inflammatory bowel conditions can cause uncomfortable or unwanted side effects,” said Dr. Joel Singer, a New York regenerative medicine physician.
For many cases, long-term relief comes with intestinal transplantation. Although the surgery can help some individuals, it is not without risks; high rejection rates and life-threatening complications caused by immunosuppression can limit its success.
Immunosuppression is a situation caused when a person receives a transplanted organ or tissue; the immune system sees the new tissue or organ as a foreign attacker and works to destroy it.
While this is a natural response of the immune system, it can cause complete rejection of the transplanted tissue or organ.
Immunosuppression can be mitigated through immunosuppressive drugs, but the use of these medications can leave transplant patients at risk of infection and other dangerous complications.
One way researchers hope to mitigate the effects of immunosuppression in intestinal transplant recipients is by tapping into the newly discovered intestinal blood cell manufacturing pool.
Why These Blood Cells Could Help
After analyzing the white blood cells in intestinal transplant recipients after they received their transplant, the researchers found that circulating white blood cells in recipients could mean that the cells stemmed from the donated intestine mature and could be “trained” to be tolerant of the recipient’s tissues. They also believe that white blood cells made in the recipient could also be taught to be tolerant of the donated intestine.
The researchers believe that the two sets of blood cells – one set from the donor and one set from the recipient – that meet and mix after the transplant “talk” to one another. This talk could protect the patient from the transplant and protect the transplant from the immune system.
The researchers found that more blood cells in the intestine from the donor could mean better outcomes for the recipient and a lower risk of rejection.
The researchers also discovered that the blood stem cells found in the transplanted intestine are replaced eventually by a pool of cells from the recipient.
How the Finding Could Improve Organ Transplantation
The researchers think that by seeding transplanted organs with extra blood stem cells, they can facilitate more of the donor-recipient cell “crosstalk” and increase the recipient’s tolerance of the transplanted tissue.
Overall, the researchers hope that their discovery could lead to improved outcomes for all types of organ transplant recipients and less immunosuppression.
Columbia University Irving Medical Center. “Some blood cells have a surprising source: Your gut.” ScienceDaily. ScienceDaily, 29 November 2018.