Researchers at Johns Hopkins have developed a new technique for delivering adult stem cells into the legs of patients to treat peripheral arterial disease, or PAD, a condition of poor circulation in the legs that affects about 10 million Americans. Left untreated, PAD progresses to serious complications, including chronic wounds, gangrene, limb loss, and even death.

The researchers used a technique that encapsulates bone marrow stem cells in “microbubbles” derived from seaweed. The stem cells, which can either be harvested from the patient’s own bone marrow or supplied by a donor, create natural proteins known as growth factors that promote the formation of new vessels, or angiogenesis.

“Using an animal model, we found that stem cells encapsulated in microbubbles dramatically improved the ability to build new blood vessels when a blood vessel in the upper leg has been suddenly closed or occluded,” said veterinary radiologist Dara L. Kraitchman, V.M.D., Ph.D., associate professor at Johns Hopkins School of Medicine.

“The goal is to use adult stem cells extracted from a healthy donor’s bone marrow and inject the cells into patients’ legs where circulation problems exist, with the hope of dramatically reducing the risk of, or avoiding amputation,” she said.

Like many conventional PAD treatments such as angioplasty and stenting that use dye studies with imaging, the microbubble stem cell treatment could also be done by an interventional radiologist using this technique to monitor a patient’s blood vessels during the injections. Hopkins researchers are continuing to test the treatment in animals and pair it with non-invasive imaging methods, such as magnetic resonance imaging (MRI). They are also fusing the results of multiple imaging techniques in order to provide a more defined picture of where to deliver the stem cells.