Mathieu Gruet1, Nicolas Decorte2, Laurent Mely3, Jean-Marc Vallier4, Boubou Camara5, Sébastien Quetant5, Bernard Wuyam2, Samuel Verges2. 1. Grenoble-Alpes University, HP2 Laboratory, 38000 Grenoble, France; INSERM, U1042, 38000 Grenoble, France; LAMHESS EA 6312, Universities of Toulon and Nice Sophia-Antipolis, France. Electronic address: gruet@univ-tln.fr. 2. Grenoble-Alpes University, HP2 Laboratory, 38000 Grenoble, France; INSERM, U1042, 38000 Grenoble, France. 3. LAMHESS EA 6312, Universities of Toulon and Nice Sophia-Antipolis, France; Regional Cystic Fibrosis Unit (CRCM), Renée Sabran Hospital, Giens, France. 4. LAMHESS EA 6312, Universities of Toulon and Nice Sophia-Antipolis, France. 5. Regional Cystic Fibrosis Unit (CRCM), Thoracic and Vascular Department, Grenoble University Hospital, France.
Abstract
BACKGROUND: Recent discovery of cystic fibrosis transmembrane conductance regulator expression in human skeletal muscle suggests that CF patients may have intrinsic skeletal muscle abnormalities potentially leading to functional impairments. The aim of the present study was to determine whether CF patients with mild to moderate lung disease have altered skeletal muscle contractility and greater muscle fatigability compared to healthy controls. METHODS: Thirty adults (15 CF and 15 controls) performed a quadriceps neuromuscular evaluation using single and paired femoral nerve magnetic stimulations. Electromyographic and mechanical parameters during voluntary and magnetically-evoked contractions were recorded at rest, during and after a fatiguing isometric task. Quadriceps cross-sectional area was determined by magnetic resonance imaging. RESULTS: Some indexes of muscle contractility tended to be reduced at rest in CF compared to controls (e.g., mechanical response to doublets stimulation at 100 Hz: 74±30 Nm vs. 97±28 Nm, P=0.06) but all tendencies disappeared when expressed relative to quadriceps cross-sectional area (P>0.5 for all parameters). CF and controls had similar alterations in muscle contractility with fatigue, similar endurance and post exercise recovery. CONCLUSIONS: We found similar skeletal muscle endurance and fatigability in CF adults and controls and only trends for reduced muscle strength in CF which disappeared when normalized to muscle cross-sectional area. These results indicate small quantitative (reduced muscle mass) rather than qualitative (intrinsic skeletal muscle abnormalities) muscle alterations in CF with mild to moderate lung disease.
BACKGROUND: Recent discovery of cystic fibrosis transmembrane conductance regulator expression in human skeletal muscle suggests that CFpatients may have intrinsic skeletal muscle abnormalities potentially leading to functional impairments. The aim of the present study was to determine whether CFpatients with mild to moderate lung disease have altered skeletal muscle contractility and greater muscle fatigability compared to healthy controls. METHODS: Thirty adults (15 CF and 15 controls) performed a quadriceps neuromuscular evaluation using single and paired femoral nerve magnetic stimulations. Electromyographic and mechanical parameters during voluntary and magnetically-evoked contractions were recorded at rest, during and after a fatiguing isometric task. Quadriceps cross-sectional area was determined by magnetic resonance imaging. RESULTS: Some indexes of muscle contractility tended to be reduced at rest in CF compared to controls (e.g., mechanical response to doublets stimulation at 100 Hz: 74±30 Nm vs. 97±28 Nm, P=0.06) but all tendencies disappeared when expressed relative to quadriceps cross-sectional area (P>0.5 for all parameters). CF and controls had similar alterations in muscle contractility with fatigue, similar endurance and post exercise recovery. CONCLUSIONS: We found similar skeletal muscle endurance and fatigability in CF adults and controls and only trends for reduced muscle strength in CF which disappeared when normalized to muscle cross-sectional area. These results indicate small quantitative (reduced muscle mass) rather than qualitative (intrinsic skeletal muscle abnormalities) muscle alterations in CF with mild to moderate lung disease.
Authors: H J Erik Hulzebos; Jeroen A L Jeneson; Cornelis K van der Ent; Maarten S Werkman; Tim Takken Journal: J Physiol Date: 2017-03-01 Impact factor: 5.182
Authors: Ren-Jay Shei; Kelly A Mackintosh; Jacelyn E Peabody Lever; Melitta A McNarry; Stefanie Krick Journal: Front Physiol Date: 2019-11-05 Impact factor: 4.566