By: Deb Butterfield
It seems obvious that the limiting factor confronting islet transplantation is the scarce supply of insulin-producing islets.
Of the approximate 6,000 cadaver donors available each year through United Network of Organ Sharing (UNOS), only half are suitable for transplantation—and these are offered first to candidates for whole-organ pancreas transplants.
At the same time, there are approximately 1.5 million people living with type 1 diabetes in the United States and 30,000 new cases of type 1 diagnosed each year.
The Problems of Insurance and Anti-Rejection Drugs
The supply of pancreases pretty much satisfies the demand because insurance coverage for the procedure is exceedingly rare, and islet recipients are required to take anti-rejection drugs for life.
But that will all change when it is possible to achieve insulin independence consistently, when insurance provides coverage and, ultimately, when islets can be transplanted without the need for anti-rejection drugs. If we do not develop the means to create an unending supply of islets, we will likely celebrate each of these advances while confronting our greatest failing—the inability to create enough cells for everyone who needs them.
Harvard Researcher Validates the Use of Stem Cells
A recent study by Douglas Melton, MD, and his colleagues at Harvard University shows that existing insulin-producing cells in the pancreas are the source for creating new cells to replace those that have been damaged or destroyed. In this study, Melton and his colleagues inserted a gene marker into the insulin-producing ‘beta’ cells of mice. These markers allowed them to observe that new cells were coming from existing beta cells.
Melton’s observation validates the work of others, like Alberto Hayek, MD, the Director of Islet Research at the Scripps Whittier Institute in San Diego, who has been multiplying beta cells for some time with the goal of creating a supply of cells for human transplantation.
Melton, who is the head of Harvard’s new Stem Cell Research Institute, went on to say that for people who have had all of their islets destroyed by disease (as have his two children with type 1), the only source of new cells may be embryonic stem cells, which can be coerced into forming beta cells.
Under President George Bush’s current policy, however, it is illegal to use federal funds to generate new lines of embryonic stem cells.
Therefore, Melton has risen above the emotional debate to develop sources of stem cells using private funds.
So far, Melton has generated 17 embryonic stem cell lines, which are made available to researchers at no cost. Melton’s will to cure his children of diabetes, his scientific expertise and his ability to overcome political whim makes him a powerful player in the cure for diabetes.