Quantification of Interstitial Cells of Cajal in the Gastric Muscle of Patients with Gastroparesis at Per-Oral Endoscopic Pyloromyotomy: A Novel Approach for Future Research in Pathogenesis of Gastroparesis.

Abstract

The role of Interstitial Cells of Cajal (ICC) in the pathogenesis of gastroparesis has been suggested by previous studies due to their involvement in the transmission of neuronal signaling to the smooth muscles of the GI tract. However, studies have been limited by the inability to obtain a gastric muscle sample, since routine endoscopy can only biopsy the mucosa. We present a new technique of muscle biopsy during per-oral endoscopic pyloromyotomy (GPOEM), a novel endoscopic procedure for treatment of gastroparesis. All enrolled patients had diagnosed gastroparesis and had biopsies of the muscular layer at the antrum/pylorus during POEM. All GPOEM procedures took place from August 2019 to December 2019. Various demographic, disease-related, and procedure-related data were collected from chart review. ICC in the biopsy specimen was examined and quantitated. Through this method, we readily expose the gastric muscle of 21 patients through dissection of a gastric submucosal tunnel during GPOEM and provide reliable muscle sample for ICC quantification. Average number of ICC were higher in clinical responders (88 ICC ± 63 vs. 39 ICC ± 24, p = 0.02), defined as those who experienced significant improvement in nausea and vomiting symptoms after GPOEM. This study provides a reliable novel biopsy method for safely biopsy gastric muscle for quantitating the number of gastric ICC in patients with gastroparesis. The number of ICC may be related to the outcome of GPOEM therapy. However, further studies with larger number of patients are needed to confirm the results.