DEC 03, 2018 10:09 PM PST

Researchers Surprised to Find a Reservoir of Blood Stem Cells in the Gut

WRITTEN BY: Carmen Leitch

There are a few major types of blood or hematopoietic cells, including red blood cells, which transport oxygen, and white blood cells, which are critical to the immune system. It had been thought that bone marrow was the only source of the many new blood cells that our body has to generate, where important hematopoietic stem cells reside. But new work by scientists at Columbia University Vagelos College of Physicians and Surgeons has found another reservoir of those stem cells: the intestine.

It seems that the human intestine might be providing up to ten percent of circulating blood cells, in a surprise to the researchers. They discovered this intestinal reservoir when researchers found donor blood cells in the blood of intestinal transplant recipients. Researchers led by Megan Sykes, MD, director of the Columbia Center for Translational Immunology, looked for the source of those donor blood cells and found hematopoietic stem cells in the donated intestine.

Intestinal transplants can be extremely critical to patients with intestinal disorders like Crohn’s disease; their intestinal function may fail and transplant becomes the only option. There are, however, high rates of rejection and serious complications from immunosuppressant drugs, and intestinal transplant success is limited.

Scientists have found that after an intestinal transplant, white blood cells in the recipient are mature, and can tolerate the tissues of the recipient. It may be possible to get them to tolerate donor tissues too.

Human HSCs in intestine. / Credit: Megan Sykes/Columbia University

"We are clearly showing that there's immunological cross-talk between the two sets of blood cells that protect the transplant from the patient's immune system and protects the patient from the transplant," said Sykes.

The investigators found that eventually, intestinal hematopoietic stem cells are replaced by a recipient pool. Blood cells made by the donated intestine may also be helpful to the recipient in the interim; patients with more donor blood cells displayed lower rates of organ rejection. This work might open new avenues for improving transplant success.

"It's possible that patients with a high level of donor cells may not require as much immunosuppression as they are currently getting," said Sykes, "and reducing immunosuppression could improve outcomes."

There might be an increase in transplant tolerance if extra donor hematopoietic stem cells are added to transplant organs.

"That could improve the lives of transplant patients dramatically," Sykes said. "Our ultimate goal is to get immune tolerance, which would allow us to remove immunosuppression altogether and have the graft treated as self by the patient. That's really the Holy Grail."

Much more work remains before this work will translate to the clinic, but the researchers are continuing their efforts. They are going to try to increase the amount of hematopoietic stem cells that are transmitted during transplant, which will hopefully raise the levels of circulating donor blood cells, benefiting immune tolerance.

The video above describes the first intestinal transplant performed in Michigan, at Henry Ford Hospital in Detroit, about six years ago.

 

Sources: AAAS/Eurekalert! via Columbia University Irving Medical Center, Cell Stem Cell

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
JUN 10, 2020
Immunology
Natural Killer Cells with "Memory" to Target Hepatitis B
JUN 10, 2020
Natural Killer Cells with "Memory" to Target Hepatitis B
An immune cell type thought to be restricted to the general, first response to pathogenic invaders may actually have som ...
JUN 14, 2020
Microbiology
Amping Up Immunity to Respiratory Viruses by Targeting Memory T Cells in the Lungs
JUN 14, 2020
Amping Up Immunity to Respiratory Viruses by Targeting Memory T Cells in the Lungs
It's easier than thought to activate immune cells that reside in the lungs and are involved in long-term immunity. Image ...
JUL 02, 2020
Cell & Molecular Biology
The Intricate Movements of a Critical Receptor are Revealed
JUL 02, 2020
The Intricate Movements of a Critical Receptor are Revealed
Scientists have now learned more about a critical protein in the brain called the NMDA receptor, tracking every atom as ...
JUL 27, 2020
Clinical & Molecular DX
Guidance for Optimization of a Real-Time qPCR Assay
JUL 27, 2020
Guidance for Optimization of a Real-Time qPCR Assay
Optimizing the formulation of reagents for your qPCR assay requires careful experimental design that looks across severa ...
JUL 25, 2020
Cell & Molecular Biology
Mammalian Cells May Have Trouble Fighting Space Bugs
JUL 25, 2020
Mammalian Cells May Have Trouble Fighting Space Bugs
New research has suggested that humans and other terrestrial mammals might have trouble identifying and responding to mi ...
AUG 05, 2020
Coronavirus
Age-old Immune Components Affecting COVID-19 Severity
AUG 05, 2020
Age-old Immune Components Affecting COVID-19 Severity
One of the most unsettling aspects of the coronavirus pandemic is the wide range of severity those affected seem to expe ...
Loading Comments...