DEAR DOCTOR K:
My teenage daughter has had Type 1 diabetes since she was 8 years old. Fortunately, exercise, a good diet and insulin treatments have kept her healthy. I recently heard of a breakthrough at Harvard that might someday cure Type 1 diabetes. Can you explain?
The research you’re referring to was conducted in the Harvard laboratory of Dr. Douglas Melton. Like you, Dr. Melton has a child with Type 1 diabetes. When his child became sick, he redirected his laboratory to the goal of finding a cure.
First, some basics. When we eat, sugar (called glucose) gets absorbed into the bloodstream. Almost every cell in our body needs glucose to function normally. However, the cells prefer a steady level of glucose in the blood — not too high, not too low, but just right (like Goldilocks).
To keep the glucose level steady, the pancreas — a finger-shaped organ in our abdomen — makes insulin. Specifically, when we eat and blood levels of glucose rise, cells in the pancreas called beta cells make insulin. Insulin drives glucose from the blood and into cells throughout the body. This lowers blood levels of glucose.
Type 1 diabetes is an autoimmune disease. For reasons that remain unclear, the immune system attacks and kills beta cells. As a result, people with Type 1 diabetes no longer can make their own insulin. Without insulin treatments, blood glucose levels rise dangerously high, and other damaging changes occur in body chemistry.
People with Type 1 diabetes require insulin every day to remain in good health. The discovery of insulin treatment for diabetes (in part by scientists here at Harvard) was a Nobel Prize-winning accomplishment. But it was not a cure. For years, scientists have dreamed of somehow replacing the beta cells that have been killed by the disease.
The discovery of stem cells — cells that have the potential to develop into different types of body cells — was exciting for medical research. Among other uses, stem cells theoretically can be coaxed into becoming cells that have been killed by disease — like beta cells in Type 1 diabetes. However, until now, no one has figured out a technique for transforming stem cells into beta cells, in the large number required to replace the beta cells killed by the disease.
Dr. Melton’s team seems to have accomplished that feat. They have been able to create billions of beta cells from one person’s stem cells. When the cells were placed inside diabetic mice, they started making insulin in just the right amounts: Blood levels of glucose were not too high, not too low, but just right.
It will be years before we know if this treatment will work in humans. If it works in the short-run, will it continue to work — will the cells truly produce a cure? And will they do so without causing complications?
So while this research does not represent a cure, it is likely to be a landmark event on the road to a cure.