
January 12, 2001
Research: Cure
Question from Alpharetta, Georgia, USA:
I have four children, and the oldest (age nine) was diagnosed with type 1 diabetes about six months ago. When my youngest child (age two-and-one-half) was born, I believe we harvested the umbilical cord. I am curious if this is potentially useful in stem cell or islet cell transplantation in the future with regard to a cure for my oldest daughter. Are you aware of any research in the area of using sibling umbilical cord blood to treat type 1 diabetes?
Answer:
Stem cell research has been in vogue recently, but despite some great successes in inducing chimeras to prevent organ rejection in transplantation, in treating certain aplastic anemias, and of course, in Parkinsonism, the techniques are still in their infancy. Moreover, there is one serious objection to using sibling stem cells to create replacement islet cells in type 1A or autoimmune diabetes, which is what I assume that your daughter has. It is that the new cells, even if the methodology was available, would still be genetically vulnerable to the autoimmune process. One day, there may a way to get around this if stem cells could be used that were derived from a person with the ‘protective’ HLA gene.
For this reason, genetic engineering skills have turned to ways of persuading cells other than islet cells to produce insulin. This too is complex because it is necessary to arrange that insulin is only produced appropriately in response to a glucose load. Last year, a group in Israel showed that mouse liver transfected with the PDX-1 gene that regulates pancreatic development could induce insulin production. Two very ingenious studies were reported at the end of last year, still mouse ones, but promising for man nonetheless. I give the references in case you have access to a Medical Library and would like to look them up. In the first, (Cheung, AT et al. Science, 290:1959,2000) mouse intestinal K cells were tranfected with the insulin gene linked to the gene for another glucose sensitive hormone called GIP. This prevented diabetes in mice with no insulin producing cells of their own. The second, (Lee HC. Nature 408:483,2000), and even more ingenious, involved the creation of a complex gene including that for a single chain insulin analog, linked to the gene for the glucose sensitive enzyme pyruvate kinase, introduced via an adenovirus vector into autoimmune diabetic mice. This produced a prolonged remission without side effects.
I’m sorry if it seems a little complicated, but the important thing is that it promises much for people with diabetes.
DOB