TY - JOUR
T1 - Activation of satellite cells in the intercostal muscles of patients with chronic obstructive pulmonary disease
AU - Martínez-Llorens, Juana
AU - Casadevall, Carme
AU - Lloreta, Josep
AU - Orozco-Levi, Mauricio
AU - Barreiro, Esther
AU - Broquetas, Joan
AU - Gea, Joaquim
PY - 2008/1/1
Y1 - 2008/1/1
N2 - OBJECTIVE: The respiratory muscles of patients with chronic obstructive pulmonary disease (COPD) display evidence of structural damage in parallel with signs of adaptation. We hypothesized that this can only be explained by the simultaneous activation of satellite cells. The aim of this study was to analyze the number and activation of those cells along with the expression of markers of microstructural damage that are frequently associated with regeneration. PATIENTS AND METHODS: The study included 8 patients with severe COPD (mean [SD] forced expiratory volume in 1 second, 33% [9%] of predicted) and 7 control subjects in whom biopsies were performed of the external intercostal muscle. The samples were analyzed by light microscopy to assess muscle fiber phenotype, electron microscopy to identify satellite cells, and real-time polymerase chain reaction to analyze the expression of the following markers: insulin-like growth factor 1, mechano growth factor, and embryonic and perinatal myosin heavy chains (MHC) as markers of microstructural damage; Pax-7 and m-cadherin as markers of the presence and activation of satellite cells, respectively; and MHC-I, IIa, and IIx as determinants of muscle fiber phenotype. RESULTS: The patients had larger fibers than healthy subjects (54 [6] vs 42 [4] μm 2; P<.01) with a similar or slightly increased proportion of satellite cells, as measured by ultrastructural analysis (4.3% [1%] vs 3.7% [3.5%]; P>.05) or expression of Pax-7 (5.5 [4.1] vs 1.6 [0.8] arbitrary units [AU]; P<.05). In addition, there was greater activation of satellite cells in the patients, as indicated by increased expression of m-cadherin (3.8 [2.1] vs 1.0 [1.2] AU; P=.05). This was associated with increased expression of markers of microstructural damage: insulin-like growth factor 1, 0.35 (0.34) vs 0.09 (0.08) AU (P<.05); mechano growth factor, 0.45 (0.55) vs 0.13 (0.17) AU (P=.05). CONCLUSIONS: The intercostal muscles of patients with severe COPD show indirect signs of microstructural damage accompanied by satellite cell activation. This suggests the presence of ongoing cycles of lesion and repair that could partially explain the maintenance of the structural properties of the muscle.
AB - OBJECTIVE: The respiratory muscles of patients with chronic obstructive pulmonary disease (COPD) display evidence of structural damage in parallel with signs of adaptation. We hypothesized that this can only be explained by the simultaneous activation of satellite cells. The aim of this study was to analyze the number and activation of those cells along with the expression of markers of microstructural damage that are frequently associated with regeneration. PATIENTS AND METHODS: The study included 8 patients with severe COPD (mean [SD] forced expiratory volume in 1 second, 33% [9%] of predicted) and 7 control subjects in whom biopsies were performed of the external intercostal muscle. The samples were analyzed by light microscopy to assess muscle fiber phenotype, electron microscopy to identify satellite cells, and real-time polymerase chain reaction to analyze the expression of the following markers: insulin-like growth factor 1, mechano growth factor, and embryonic and perinatal myosin heavy chains (MHC) as markers of microstructural damage; Pax-7 and m-cadherin as markers of the presence and activation of satellite cells, respectively; and MHC-I, IIa, and IIx as determinants of muscle fiber phenotype. RESULTS: The patients had larger fibers than healthy subjects (54 [6] vs 42 [4] μm 2; P<.01) with a similar or slightly increased proportion of satellite cells, as measured by ultrastructural analysis (4.3% [1%] vs 3.7% [3.5%]; P>.05) or expression of Pax-7 (5.5 [4.1] vs 1.6 [0.8] arbitrary units [AU]; P<.05). In addition, there was greater activation of satellite cells in the patients, as indicated by increased expression of m-cadherin (3.8 [2.1] vs 1.0 [1.2] AU; P=.05). This was associated with increased expression of markers of microstructural damage: insulin-like growth factor 1, 0.35 (0.34) vs 0.09 (0.08) AU (P<.05); mechano growth factor, 0.45 (0.55) vs 0.13 (0.17) AU (P=.05). CONCLUSIONS: The intercostal muscles of patients with severe COPD show indirect signs of microstructural damage accompanied by satellite cell activation. This suggests the presence of ongoing cycles of lesion and repair that could partially explain the maintenance of the structural properties of the muscle.
KW - COPD
KW - Damage
KW - Muscle dysfunction
KW - Repair
KW - Satellite cells
U2 - 10.1157/13119938
DO - 10.1157/13119938
M3 - Article
SN - 0300-2896
VL - 44
SP - 239
EP - 244
JO - Archivos de Bronconeumologia
JF - Archivos de Bronconeumologia
IS - 5
ER -