Muscle Cell Infusion Strengthens Sphincters

Researchers at Stanford University recently completed a study showing that muscle cells grown in a lab setting and then injected into the esophageal sphincter may strengthen the sphincter, work that could ultimately help in the treatment patients with GERD and fecal incontinence.

The study aimed to test “whether skeletal muscle, the kind that moves your bones and is easily accessible by biopsy, could grow and function within the smooth, not consciously controlled, muscles of the gastrointestinal sphincters,” according to Stanford professor of medicine and lead author of the study Pankaj Pasricha, MD.

To test this, the researchers performed two experiments. During the first step, in order to “test the cells' ability to integrate and change the sphincter’s ability to contract,” the researchers injected 200,000 muscle cells into six adult rats in between the sphincter that separates the stomach and small intestine. The second experiment involved the same technique, performed on dogs, to test its usefulness in the lower esophageal sphincter.

Four weeks into the first experiment sphincter muscle contraction was measured in response to an injection of acetylcholine. According to the researchers, “sphincters injected with muscle cells had significantly higher contraction pressures.” Even at the lowest concentration of acetylcholine, the contractions “more than doubled in the treatment group,” the researchers said.

During the second part of the study, when four billion muscle cells were injected into the lower esophageal sphincter of the dogs, the researchers found that sphincter pressure had doubled after three weeks.

When the researchers tested the dogs for signs of acid reflux before the study began, one displayed signs of the condition. When that dog was tested again at the three-week point, its esophagus had gone from “excessively acidic 26.5% of the time” to 1.5% of the time.

According to the researchers, the results of this study may one day mean that patients who suffer from GERD would have a much less invasive treatment option.

The new procedure “theoretically would take about 10 minutes to do, it would be an outpatient procedure, minimal sedation and the patient could go home in about an hour,” said Pasricha.

Results of the study were also published in Gastrointestinal Endoscopy.