title: Contractile elements in muscular fascial tissue - implications for in-vitro contracture testing for malignant hyperthermia.
abstract: Malignant hyperthermia is a dreaded complication of general anaesthesia. Predisposed individuals can be identified using the standardised caffeine/halothane in-vitro contracture test on a surgically dissected skeletal muscle specimen. Skeletal muscle is composed of muscle fibres and interwoven fascial components. Several malignant hyperthermia-associated neuromuscular diseases are associated with an altered connective tissue composition. We analysed adjacent fascial components of skeletal muscle histologically and physiologically. We investigated whether the fascial tissue is sensitive to electrical or pharmacological stimulation in a way similar to the in-vitro contracture test for diagnosing malignant hyperthermia. Using immunohistochemical staining, α-smooth muscle actin-positive cells (myofibroblasts) were detected in the epi-, endo- and perimysium of human fascial tissue. Force measurements on isolated fascial strips after pharmacological challenge with mepyramin revealed that myofascial tissue is actively regulated by myofibroblasts, thereby influencing the biomechanical properties of skeletal muscle. Absence of electrical reactivity and insensitivity to caffeine and halothane suggests that, reassuringly, the malignant hyperthermia diagnostic in-vitro contracture test is not influenced by the muscular fascial tissue.
authors.affiliation: Department of Anaesthesiology, Ulm University, Ulm, Germany; Department of Anaesthesia, Intensive Care Medicine and Pain Therapy, Frankfurt University, Frankfurt am Main, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Hoppe
authors.forename: R
authors.initials: R
authors.lastname: Schleip
authors.forename: F
authors.initials: F
authors.lastname: Lehmann-Horn
authors.forename: H
authors.initials: H
authors.lastname: Jäger
authors.forename: W
authors.initials: W
authors.lastname: Klingler
mesh_terms: D000768:Anesthesia, General / Q000009:adverse effects; D018681:Anesthetics, General / Q000009:adverse effects*; D000818:Animals; D001706:Biopsy; D002110:Caffeine; D000697:Central Nervous System Stimulants; D004558:Electric Stimulation; D005152:Facial Muscles / Q000187:drug effects*; D005455:Fluorescent Antibody Technique; D006221:Halothane; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008305:Malignant Hyperthermia / Q000175:diagnosis*; D051379:Mice; D008807:Mice, Inbred BALB C; D009119:Muscle Contraction / Q000187:drug effects*; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D018681:Anesthetics, General; D000697:Central Nervous System Stimulants; D006634:Histamine H1 Antagonists; D002110:Caffeine; D011738:Pyrilamine; D006221:Halothane