A recent study in mice concludes that targeted ultrasound could be an effective, noninvasive, drug-free way to boost insulin levels in people with type 2 diabetes.

According to the Centers for Disease Control and Prevention (CDC), type 2 diabetes now affects more than 100 million adults in the United States. It was the seventh-leading cause of death in the United States in 2015.

In people with diabetes, the pancreas produces too little insulin. For this reason, over time, the body becomes less sensitive to it in a condition called insulin resistance. Beta cells—which are specialized cells in the pancreas—synthesize, store, and release insulin in response to the presence of sugar in the blood. This increased production helps keep levels of glucose in the blood within the normal range; too much sugar in the blood can damage tissues and organs.

Early on in the progression of diabetes, beta cells can become overworked, which causes insulin to build up inside. This buildup can be terminal for the beta cell. If more insulin-producing beta cells die, diabetes is exacerbated. Certain drugs can help the beta cells release insulin, but these can be expensive and may become less effective over time. For these reasons, researchers are keen to find other ways of promoting insulin release that do not involve drugs.

A rebirth for ultrasound

Researchers at George Washington University in Washington, DC, are investigating an innovative way to treat diabetes. They believe that ultrasound might provide a way forward. The scientists recently presented their latest findings at the 177th Meeting of the Acoustical Society of America in Louisville, KY.

The researchers used ultrasound to stimulate insulin release from beta cells in the pancreases of mice. They transmitted sound to the abdomen transcutaneously, or without breaking the skin. Ultrasound describes sound waves of a frequency above the level of human hearing. In the medical world, people most commonly associate ultrasound with scanning technology, for instance, imaging the fetus.

Scientists have used ultrasound as a diagnostic tool for decades, but more recently, they have started to investigate whether it might also be useful as a treatment for certain conditions. For instance, some now use ultrasound to break apart kidney stones while they are still in the body.

Some researchers are interested in finding out whether ultrasound might even become a treatment option for Parkinson's disease. Others still are studying the use of so-called high-intensity focused ultrasound as a way of fighting prostate cancer.

Ultrasound and diabetes

In previous work, scientists have shown that ultrasound can encourage cultured beta cells to release insulin. In the latest study, the researchers wanted to understand whether this would be possible in a living animal.

To investigate, they gave mice either a sham (control) treatment or a single 5-minute exposure to ultrasound at the frequency of 1 megahertz. The researchers took blood samples immediately before and after the ultrasound or control session. Importantly, there appeared to be no damage to the skin or internal organs of the mice. As hoped, the scientists found that the mice they treated with ultrasound had increased insulin production compared with the control mice.

However, importantly, they also found that there was no associated reduction in glucose levels; despite a hike in insulin, glucose in the blood seemed untouched. This was unexpected, so they are eager to examine this further. Despite this, the study authors' conclusions are upbeat:

"We expect that our approach, with careful selection of ultrasound parameters, may provide a safe, controlled, and targeted stimulation of insulin release from the pancreatic beta cells."

As ever, it will be a complicated journey; as study co-author Tania Singh explains, "The pancreas has a number of other roles in addition to producing insulin, including the release of antagonistic hormones and digestive enzymes."

In other words, if one stimulates the pancreas, there is a strong possibility that it might boost the excretion of other biological products alongside insulin. This could have a range of effects. The scientists are keen to investigate this potential problem in more detail. Although the results are fascinating and likely to generate discussion, these are very early days; as Singh explains, "Our work is an important first step in stimulating endocrine tissue."

To answer the question posed in the title, ultrasound may, in the future, be useful for the treatment of diabetes. Right now, however, that future seems to be a long way off.