Effects of acid-induced esophagitis on esophageal smooth muscle

Abstract

Acid-induced esophagitis is associated with sustained longitudinal smooth muscle (LSM) contraction and consequent esophageal shortening. In addition, LSM strips from opossums with esophagitis are hyper-responsive, while the circular smooth muscle (CSM) contractility is impaired. To determine the origin of these changes, studies were performed on esophageal smooth muscle cells isolated from opossum esophagi perfused intraluminally on 3 consecutive days with either saline (control; n = 8) or HCl (n = 9). CSM and LSM cells, obtained by enzymatic digestion, were exposed to various concentrations of carbachol (CCh) and fixed. CCh induced concentration-dependent contraction of both LSM and CSM cells. CCh-induced LSM cell contraction was not different between control and esophagitis animals; however, there was marked attenuation in the CCh-induced contraction of CSM cells from esophagitis animals. Morphological studies revealed significant hypertrophy of the CSM cells. These findings suggest that impaired CSM contractility can be attributed at least in part to alterations to the CSM cell itself. In contrast, hyper-contractility demonstrated in LSM strips is likely related to factors in the surrounding tissue.

Persistent and selective effects of inflammation on smooth muscle cell contractility in rat colitis

“…The protocol used for isolation of CSMC was similar to that previously described [39]. Briefly, the mid-descending colon was removed and placed in fresh Krebs' solution (in mM: NaHCO 3 25; NaCl 118; KCl 4.7; NaH 2 PO 4 1; MgSO 4 1.2; glucose 11; CaCl 2 2.5; bubbled with 95%O 2 /5%CO 2 ).…”

“…To address these questions, we have modified a recently developed cell isolation technique [39] to obtain a high yield of long, viable SMC that likely represents the in vivo status of the cell, and can thus optimally identify alterations in cellular contractility. We applied this technique to the model of TNBS-induced rat colitis, to characterize the effects of inflammation on the response of individual CSMC to the excitatory agonists carbachol (CCh), 5-HT, and histamine over the time course of inflammation from onset to overt recovery (as characterized by the absence of inflammation).…”

Importance of ineffective esophageal motility in patients with erosive reflux disease on the long-term outcome of Nissen fundoplication

“…In animal studies, the loss of esophageal function has been shown to be a direct consequence of inflammatory injury, affecting muscularis propria and causing decreased muscle tone and contraction amplitudes, as well as esophageal shortening [27,28]. In a study which combined intraluminal esophageal ultrasound with esophageal 24-hour pH metry, manometry, and endoscopy, it has been shown that patients with GERD and IEM had decreased esophageal muscle thickness opposed to GERD patients with normal motility [29].…”

Impaired acetylcholine-induced smooth muscle contraction in colitis involves altered calcium mobilization and AKT phosphorylation

“…The isolation of colonic CSMC has been previously described [7,20]. Briefly, strips of circular smooth muscle were isolated from the mid-descending colon and placed into 4-2-hydroxyethyl-1-piperazineethanesulfonic acid (HEPES) physiological salt solution (HPSS)-digestion solution.…”