Interstitial cells of Cajal (ICC) are vital for transmitting neuronal signals to the smooth muscles in GI tract, acting as a pacemaker. ICC are implicated in motility disorders, including gastroparesis. ICC are in the muscularis propria, therefore cannot be biopsied during routine endoscopy, during which only gastric mucosal layer can be biopsied. Our prior study demonstrated the feasibility and safety of gastric muscle biopsy at gastric per-oral endoscopic pyloromyotomy (G-POEM) for study of ICC. Previous research indicated reduced ICC cells in delayed gastric emptying animal models and gastroparesis patients. However, variations in ICC numbers among gastroparesis patients with different etiologies are unexplored. This study aims to elucidate potential differences in ICC numbers associated with diverse etiologies in gastroparesis patients.
Methods
Patients with a confirmed diagnosis of gastroparesis who underwent a planned G-POEM at two institutions* and two time periods (August 2019-December 2019 and September 2022-November 2023) were enrolled in this study. Gastric muscle samples were obtained during G-POEM and autopsy gastric antral specimens from a healthy adult population, collected between September 2022 and November 2022, served as controls. ICC from gastric antral muscle samples were examined and quantitated in a 4mmsq piece. One-way analysis of variance was employed to determine statistical significance among ICC in patients with different etiologies, and a two-sample T-test was used to determine statistical significance in ICC between patients with and without gastroparesis, specifically in individuals without gastroparesis.
Results
84 patients were included in this study. The participants had an average age of 48.6 years, 77.6% were females, and 17.6% of these were 65 or older. 47.6% of the patients had diabetic gastroparesis, 16.7% had post-surgical gastroparesis and 35.7% of the patients had idiopathic gastroparesis. Analysis indicated no significant variability in the number of interstitial cells of Cajal among the three groups (diabetic, postsurgical, and idiopathic). The average number of ICC/4mmsq was 409.14, and it was noted that this number did not vary with age. Additionally, the average number of ICC in the gastroparesis population was significantly lower compared to the control group (409 vs. 1422 cells per 4mmsq area, p-value < 0.0001).
Conclusion:
No differences were found in the number of ICC among the different etiologies of gastroparesis, such as diabetes, post-surgery, or idiopathic cases. To our knowledge, this is the first report on the number of ICC in gastroparesis patients for each etiology. The study further confirmed that the number of ICC was significantly lower when compared to that of individuals without gastroparesis.
*Emory University and Louisiana State University Shreveport

Michael Tran

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