Type 1 diabetes is marked by a loss of insulin-producing beta cells in the pancreas. Without insulin, blood sugar can’t shuttle into the body’s energy-hungry organs and tissues. As a result, sugar accumulates in the blood which, over time, causes many serious complications such as kidney disease, heart disease and stroke. An over-reactive immune system is to blame which mistakes the beta cells for foreign invaders and attacks them.
Much of the focus on diabetes therapy development is turning stem cells into beta cells in order to replace the lost cells. But a recent Stem Cell Translational Medicine publication describes a different approach that uses umbilical cord blood stem cells to tame the immune system and preserve the beta cells that are still intact.
The research team, composed of scientists from the U.S., China and Spain, devised a technology they call Stem Cell Educator (SCE) therapy that draws blood from a diabetic patient then separates out the lymphocytes – the white blood cells of the immune system – which trickle through a series of stacked petri dishes that contains cord blood stem cells. Because the stem cells are attached to the surface of the device, only the lymphocytes are recovered and returned to the patient’s blood. The idea is that through this forced interaction with the cord blood stem cells – which have been shown to blunt immune cell activity – the patient’s own lymphocytes “learn” to quiet their damaging response to beta cells.
In a series of clinical trials in China and Spain from 2010 to 2014, the researchers showed that a single treatment of the SCE therapy restored beta cell function and blood sugar control in patients. Though the treatment appeared safe and effective after one year, how exactly it worked remained unclear. So, in this current study, the team aimed to better understand cord blood stem cell function and to perform a 4-year follow up on the patients.
Shortly after the SCE therapy, the researchers had observed elevated levels of platelets in the blood. They examined these cells more closely to see if they contained any factors that would dampen the immune response. Sure enough, the platelets carried a protein called autoimmune regulator (AIRE) which plays a role in inhibiting immune cells that react against the body.
Now, platelets do not contain a nucleus or nuclear DNA but they do have mitochondria – a cell’s energy producers – which contain their own DNA and genetic code. An analysis of the mitochondrial DNA revealed that it encoded proteins associated with the regeneration and growth of pancreatic beta cells. In an unusual finding in the lab, the researchers showed that the platelets release their mitochondria, which can be taken up by pancreatic beta cells where these beta cell associated proteins can exert their effects.
HealthDay reporter Serena Gordon interviewed Julia Greenstein, vice president of discovery research at JDRF, to get her take on these results:
“The platelets seem to be having a direct effect on the beta cells. This research is intriguing, but it needs to be reproduced.”
For the four-year follow up study, nine of the type 1 diabetes patients from the original trial in China were examined. Two patients who were treated less than a year after being diagnosed with diabetes still had normal levels of insulin in their blood and were still free of needing insulin injections. In the other seven patients, the single treatment had gradually lost its effectiveness. Team leader Dr. Yong Zhao of the University of Hackensack in New Jersey, felt that a single treatment possibly isn’t enough in those patients:
“Because this was a first trial, patients just got one treatment. Now we know it’s very safe so patients can receive two or three treatments.”
I imagine Dr. Zhao will be testing out multiple treatments in a clinical trial that is now in the works here in the states at Hackensack Medical Center. Stay tuned.