Loss of α-smooth muscle actin immunostaining is not a useful marker for functional impairment: a comparison from patients with and without small bowel motility disorder

Abstract

Abstract Introduction/Objective Prior studies have reported the loss α-smooth muscle actin (α-SMA) immunostaining in the inner circular layer of the muscularis propria in small bowel motility disorder cases, but this remains controversial with conflicting data. In this study we aimed to characterize the immunoreactivity of α-SMA expression in the muscularis propria of the small intestine, specifically jejunum, in patients with and without small bowel motility disorder. Methods/Case Report A total of 28 samples of transmural proximal jejunum biopsies from adult patients with small bowel motility disorder by manometric and/or radiologic testing and 47 control tissues were evaluated. The controls were full thickness, longitudinal tissue sections from segmental resections performed due to trauma from gunshot wound (n= 30), multi-visceral transplant for neoplasms (n= 4), liver failure with concurrent portal vein thrombosis (n= 9), and isolated intestinal transplant for Crohn disease (n= 4). Immunostaining for α-SMA was performed with appropriate controls to confirm the presence of staining in the circular and longitudinal muscle layers of the muscularis propria in each sample and recorded as retained or diminished. Results (if a Case Study enter NA) In the small bowel motility disorder and control cases, 43% (12/28) and 62% (29/47) of the cases showed no or minimal α-SMA expression in the inner circular layer with peripheral accentuation (p = 0.113), respectively. The remaining small bowel motility disorder cases (16/28, 57%) and the control group (18/47, 38%) showed retained expression of α-SMA in both layers of the muscularis propria. Conclusion Loss or diminished α-SMA expression in the inner circular layer of muscularis propria is present in similar frequency in cases with and without small bowel motility disorder and does not correlate with impairment of function.