Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility

Abstract

It has been shown, in animal models, that gastrointestinal tract (GIT) motility is influenced by temperature; nevertheless, the basic mechanism governing thermal GIT smooth muscle responses has not been fully investigated. Studies based on physiologically tuned mathematical models have predicted that thermal inhomogeneity may induce an electrochemical destabilization of peristaltic activity. In the present study, the effect of thermal cooling on human colonic muscle strip (HCMS) contractility was studied. HCMSs were obtained from disease-free margins of resected segments for cancer. After removal of the mucosa and serosa layers, strips were mounted in separate chambers. After 30 min, spontaneous contractions developed, which were measured using force displacement transducers. Temperature was changed every hour (37, 34, and 31°C). The effect of cooling was analyzed on mean contractile activity, oscillation amplitude, frequency, and contraction to ACh (10(-5) M). At 37°C, HCMSs developed a stable phasic contraction (~0.02 Hz) with a significant ACh-elicited mean contractile response (31% and 22% compared with baseline in the circular and longitudinal axis, respectively). At a lower bath temperature, higher mean contractile amplitude was observed, and it increased in the presence of ACh (78% and 43% higher than the basal tone in the circular and longitudinal axis, respectively, at 31°C). A simplified thermochemomechanical model was tuned on experimental data characterizing the stress state coupling the intracellular Ca(2+) concentration to tissue temperature. In conclusion, acute thermal cooling affects colonic muscular function. Further studies are needed to establish the exact mechanisms involved to better understand clinical consequences of hypothermia on intestinal contractile activity.

Smooth Muscle Strips for Intestinal Tissue Engineering

“…6 ; S1 Video ). This periodic contraction was qualitatively less than the maximum contraction observed with pharmacological stimulants such as potassium chloride or carbachol, but similar to the ∼30% change amplitude of contraction in acetylcholine-induced fresh smooth muscle [36] . Native stripped intestinal smooth muscle contracted visibly and with a large flux of calcium intensity ( Fig.…”

Supernatants of irritable bowel syndrome mucosal biopsies impair human colonic smooth muscle contractility

“…After removal of the mucosa and submucosa layers, colonic smooth muscle was cut into small strips (10 mm long by 2 mm wide, 0.8±0.4 g weight) by sharp dissection, identifying the circular orientation, according to the position of the taenia coli . The strips were mounted in separate 10‐mL chambers as previously described and were oriented to measure isometric tension in circular muscle. Strips were initially stretched to 15 g of load, to bring them near conditions of optimum force development, and equilibrated for an additional 30 minutes after continuous perfusion with oxygenated Krebs solution.…”

Computational model of gastric motility with active‐strain electromechanics

“…recently proposed a generalized thermodynamical framework with a statistical description of the intestinal wall microstructure . Moreover, some attempts to characterize the altered mechanical contractility of human colon strips in the presence of unbalanced thermal states were proposed over the last years . What remains wanted so far is a computational model that combines a simple phenomenological, and computationally robust model of gastric electrophysiology with an electro‐mechanical finite elasticity framework, enabling thereby comprehensive studies of the complex multiphysical nature of gastric motility on the organ level.…”