It almost sounds like a videogame. Inject a patient with tiny bubbles and use ultrasound waves to burst them open when they float to the right spot. While the term “microbubbles” may sound more whimsical than medical, a Dallas doctor is a national pioneer in using them to fight diabetes. And it's a technology that was born on the battlefield.
No matter your age, the pinging of sonar probably conjures up images of wartime and submarines.
“That uses sound waves bounced off the hull of a submarine,” says Dr. Paul Grayburn, director of cardiology research at Baylor. “Well, now we can bounce sound waves off of organs in your body and image them and see disease states and see normal function and really tell a lot about what’s going on.”
Grayburn uses sonograms, or ultrasound, all the time to see the heart. It is a tricky organ, because the ribcage can obscure it, making it hard to get a good picture. But a new development has made Grayburn’s job a whole lot easier, and it too comes courtesy of the military. He calls it the "cavitation" of microbubbles.
“When a submarine propeller turns, little tiny bubbles like you might see in a champagne glass. And you can listen to them because they make a noise,” Grayburn says. “And so we were able to use that cavitation of the bubbles to detect whether it was a Russian or an American submarine, how fast it was going, all kinds of specific signatures. And much of that was classified for years.”
So how do tiny bubbles make it easier to take ultrasounds of the heart?
“Because it is really easy to see the difference between bubbles inside the heart and the cardiac walls. So we use it all the time to make the pictures better and to get a more accurate diagnosis,” he says.
But microbubbles have taken researchers far beyond ultrasound clarity. Each bubble, less than half the size of a red blood cell, can also act a courier.
“So we’ve learned that we can attach genes to the microbubbles and then circulate them throughout the body,” Grayburn says. “And we can actually destroy the microbubbles or cause them to cavitate, much like a propeller causes them to. So that means we can actually blow these bubbles up within the organ we want to deliver the gene to.”
And Grayburn, who is one of the country’s leading researchers in this field, hopes that means the beginning of the end for diabetes.
By loading microbubbles with genes designed to kick-start the pancreas, and bursting those bubbles in just the right spot, a diabetic could start producing insulin again.
“The islets are the part of the pancreas that produces insulin, and we can cause them to grow back by putting these genes in and delivering that gene specifically to the part of the pancreas that needs to regenerate,” says Grayburn.
And for diabetics like 79-year-old Patricia Moreland of Waxahachie, that would be a welcome advance. She was diagnosed with Type 2 diabetes in 1995, and it’s been debilitating.
“It’s horrendous; it is not anything I would wish on my worst enemy. Just recently I had a retina bleed that was directly because of diabetes,” she says.
Moreland was originally able to control her diabetes with diet and exercise, then tablet medication, and finally last January, she was forced to go on insulin. She’s used to her twice-daily injections now, but the first attempt left her with a terrible bruise.
“It was as large as a man’s double fist,” she said.
Dr. Grayburn says his team has seen very promising results when testing this gene therapy on rats and baboons, though he guesses we’re at least five years away from human use.
But Patricia Moreland is encouraged all the same. She’s always loved caring for plants, and says the indoor activity is one she can still enjoy, despite diabetes.
She can no longer drive at night, which meant resigning from her beloved church choir. And she says her rigid schedule of meals, medication and injections makes her a slave to the clock.
“It’s just sheer, pardon my French, guts and willpower, because it’s not fun,” she says. “I have had to give up a lot of things that I have enjoyed for years because of diabetes.”
But Dr. Grayburn thinks with the help of ultrasound, he’s well on the way to bursting diabetes’ bubble.