Pre-treated blood stem cells reverse type 1 diabetes in mice
Type 1 diabetes is caused by an immune attack on the pancreatic beta cells that produce insulin. To curb the attack, some researchers have tried rebooting patients’ immune systems with an autologous bone-marrow transplant, infusing them with their own blood stem cells. But this method has had only partial success.
New research in today’s Science Translational Medicine suggests a reason why.
“We found that in diabetes, blood stem cells are defective, promoting inflammation and possibly leading to the onset of disease,” says Paolo Fiorina, MD, PhD, of Boston Children’s Hospital, senior investigator on the study.
But they also found that the defect can be fixed — by pre-treating the blood stem cells with small molecules or with gene therapy, to get them to make more of a protein called PD-L1.
In experiments, the treated stem cells homed to the pancreas and reversed hyperglycemia in diabetic mice, curing almost all of them of diabetes in the short term. One third maintained normal blood sugar levels for the duration of their lives.
In a dish, the modified blood stem cells curbed the autoimmune reaction in cells from both mice and humans.
“There’s really a reshaping of the immune system when you inject these cells,” says Fiorina, a researcher in the Division of Nephrology at Boston Children’s.
The powers of PD-L1
Fiorina, Moufida Ben Nasr, PhD, and colleagues began by using gene expression profiling to find out what proteins blood stem cells make. They discovered that blood stem cells from diabetic mice and humans have alterations in the network of genetic re Continue reading