Pathway to a cure  pg. 2

“Our research really has a chance to help people; it’s not just an academic question whose answer might be in the textbooks, if you’re lucky.”

Wright’s team and a handful of other laboratories are seeking the set of genes that control the development of the specialized cells of the pancreas. “If we can identify the factors that make a pancreas,” Wright says, “we might be able to coerce embryonic stem cells or other cells to turn into pancreas.”

Success could mean unlimited supplies of insulin-producing cells for transplantation therapy. And transplantation appears to be as close to a cure for diabetes as we’ve come.

Only one kind of cell in the body — the pancreatic beta cell — can sense blood sugar and respond by secreting insulin. Destruction of these precious cells by a person’s own immune system gives rise to type 1 diabetes.

Although glucose testing and insulin injections can stand in for the lost beta cells, they cannot begin to match the minute-to-minute control of blood sugar normally exerted by these cells. While intensive insulin therapy reduces the long-term complications of diabetes, it does not eliminate these complications and often results in dangerous episodes of hypoglycemia.

So why not simply replace the lost beta cells with new ones? That is the premise of transplantation therapy as a cure for diabetes.

One option is to transplant an entire pancreas, and indeed, pancreas transplantation has proven successful in restoring normal blood sugar levels. Unfortunately, the procedure carries high morbidity and mortality rates, restricting it as a therapy to those patients with diabetes and significant end-stage organ disease like renal failure.

The majority of patients with type 1 diabetes need a safer alternative. Perhaps, investigators reasoned, the surgical complications of full pancreas transplants could be avoided by transplanting only the “islets of Langerhans,” named for the German pathologist who first described the characteristic cell islands in the pancreas. Islets are home to the insulin-producing beta cells, along with several other hormone-releasing cell types.

The idea showed early promise. In 1972, Paul Lacy at Washington University in St. Louis reported that islet transplantation could cure diabetes in rats. Investigators raced to apply the procedure to human beings. But of the hundreds of attempts made over the next 20-plus years, less than 10 percent resulted in insulin independence.

More encouraging results began to surface in the late 1990s, with groups in Miami, Minneapolis, and Milan achieving longer periods of islet cell survival, higher percentages of insulin independence, and, for those transplant patients who still required insulin, avoidance of the dangerous blood sugar extremes.

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