Both of Doug Melton’s children developed type 1 diabetes as infants. His wife, as he says, became their pancreas — figuring out when each one’s blood sugar was too high, and they needed insulin or too low, and they needed food.

Melton, a Harvard University researcher, decided his own contribution would be to cure type 1 diabetes. He retooled his lab and set to work.

His son, diagnosed at 6 months old, is now 28.

“I thought by now I would have cured the disease,” Melton admits. “It's taken much longer than I thought.”

For nearly a century, the treatment of diabetes has remained essentially the same: injecting insulin to balance the body’s blood sugar and allow food to be converted to fuel.

Joanne Rhoton of Everett has diabetes and here she demonstrates how she tests her blood sugar level. (Jesse Costa/WBUR)

But researchers have been making progress recently, and a lot of improvements ­-- and even a cure — may be on the horizon, experts say.

“We're at this very exciting period in the science where we have human clinical trials showing promise … that could ultimately cure this disease,” says Cynthia Rice, senior vice president of the Juvenile Diabetes Research Foundation.

Any cure, Melton says, will depend on restoring the body’s own ability to make and deliver insulin.

“Evolution has made a cell whose job is to measure sugar and secrete out insulin,” he says. “I believe that the biological solution — sort of nature’s solution — is the right answer to the problem.”

After more than a decade of trial-and-error research, Melton has figured out how to make beta cells, the cells in the pancreas that measure glucose levels and squirt out insulin as needed.

Melton holds up a vial between his thumb and forefinger. Tipping it back and forth stirs up what look like black dots floating in water. They’re beta cells, manufactured in his lab down the hall.

He’s already shown in animals that his manufactured beta cells can measure glucose and secrete insulin when the body needs it. Next year, a biotech company Melton helped found, Semma Therapeutics, will launch a clinical trial to see if they can work in people, too.

“It’s maybe a funny way to say it, but there's nothing we are learning that tells me this can't be cured,” Melton says. “There are problems that we're having trouble solving, and it's taking longer than I want. But I'm convinced that those cells will cure the disease.”

But even if his cells work perfectly, Melton will only have solved half the problem.

In type 1 diabetes, the immune system attacks the beta cells that produce insulin. If Melton put his beta cells into someone with type 1 diabetes, their immune system would attack the new cells, too.

So, the second half of the problem will require protecting those cells.

Each of these containers represents one of the major steps in Doug Melton's recipe for making human beta cells from multi-purpose stem cells. (Courtesy Mary Bergman/Harvard University)

Melton and other researchers are working on some ideas. One, Melton likens to putting the beta cells into a tea bag.

“The insulin and the glucose can go across, but the cells stay in,” he says. “And importantly the immune cells can't go in and attack it.”

Semma Therapeutics, backed by more than $100 million in venture funding, will be testing that approach next year, too.

Melton and colleagues at the Joslin Diabetes Center have also been looking for genes they can edit in these manufactured beta cells to make them invisible to the immune system.

By editing and testing the genes one by one, the researchers found that only about a dozen seemed to hide the beta cells from the immune system of mice with a version of type 1 diabetes. One gene had already been known as a risk gene for type 1 diabetes.

“We think that when you mutate that one gene, you protect the cells against the autoimmune attack without really changing the beta cell and without preventing it from being recognized by the immune system,” said Stephan Kissler, an assistant professor at Harvard and an investigator at Joslin, who has been working with Melton. Eventually, he hopes to be able to gene-edit manufactured beta cells before they’re delivered to a patient, so they’ll work like regular beta cells but won’t suffer the same immune attacks.

It’s too early to know how much such a cure might cost patients. Melton says his research has cost tens of millions of dollars over the last 15 years, provided mainly by federal grants and private foundations. But that pales in comparison to the roughly $200 billion that the U.S. government spends every year to treat diabetes.

“So, I would say if it takes us $50 or $100 million to cure the disease over a period of 15 to 20 years – that's a bargain,” Melton says.

Dr. David Nathan, who directs the Diabetes Center at Massachusetts General Hospital, says the idea of curing diabetes is enticing, but he cautions that it will be a long time before any cures are available to patients.

“They're coming along, but I don't see that on the near horizon,” he says. “I think that's going to take maybe another decade if we get lucky.”

In the meantime, he’s looking for ways to make diabetes treatment easier and more effective. He’s particularly excited about what is described as an artificial pancreas, named for the organ where insulin is made. In an artificial pancreas, a computer-controlled algorithm connects a blood sugar monitor and an insulin pump, automatically adjusting the delivery of insulin to minimize blood sugar highs and lows.

“They will be available I think in the next two to three years,” Nathan predicts, and they “will revolutionize the treatment of type 1 diabetes.”

Cynthia Rice at JDRF says she’s eagerly awaiting a new technology called smart insulin that her organization has helped develop. “Smart” insulin circulates through the bloodstream and automatically activates or deactivates in response to changing blood sugar levels, providing tighter control than is currently possible.

“You'd have to take an injection maybe once a day or once a week, and it would provide the right amount of insulin at the right time,” Rice says.

In the meantime, Melton is still working toward a cure.

“I think about it all the time,” he says.” I wake up thinking about it. It's it is a quest that we are not going to give up on.”