Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility.
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.
Gastroenterology Unit, University Campus Bio-Medico of Rome, Rome, Italy;
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Altomare
Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Rome, Italy; and.
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Gizzi
Gastroenterology Unit, University Campus Bio-Medico of Rome, Rome, Italy;
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Guarino
Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Rome, Italy; and.
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Loppini
Gastroenterology Unit, University Campus Bio-Medico of Rome, Rome, Italy;
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Cocca
Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Rome, Italy; and Politecnico di Milano, Milano, Italy; and.
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Dipaola
Surgery Unit, University Campus Bio-Medico of Rome, Rome, Italy;
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Alloni
Gastroenterology Unit, University Campus Bio-Medico of Rome, Rome, Italy; m.cicala@unicampus.it.
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Cicala
Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Rome, Italy; and International Center for Relativistic Astrophysics, Pescara, Italy.
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Filippi
D000109:Acetylcholine / Q000494:pharmacology; D000368:Aged; D002118:Calcium / Q000378:metabolism; D003080:Cold Temperature; D058639:Cold-Shock Response; D003106:Colon / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D040542:Mechanotransduction, Cellular; D008875:Middle Aged; D008954:Models, Biological; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors
D000109:Acetylcholine; D002118:Calcium
human colonic smooth muscle strips; mathematical model; postoperative ileus; thermal cooling; thermochemomechanical coupling