Reduced satellite cell number in situ in muscular contractures from children with cerebral palsy.
Satellite cells (SC) are quiescent adult muscle stem cells critical for postnatal development. Children with cerebral palsy have impaired muscular growth and develop contractures. While flow cytometry previously demonstrated a reduced SC population, extracellular matrix abnormalities may influence the cell isolation methods used, systematically isolating fewer cells from CP muscle and creating a biased result. Consequently, the purpose of this study was to use immunohistochemistry on serial muscle sections to quantify SC in situ. Serial cross-sections from human gracilis muscle biopsies (n = 11) were labeled with fluorescent antibodies for Pax7 (SC transcriptional marker), laminin (basal lamina), and 4',6-diamidino-2-phenylindole (nuclei). Fluorescence microscopy under high magnification was used to identify SC based on labeling and location. Mean SC/100 myofibers was reduced by ∼70% (p < 0.001) in children with CP (2.89 ± 0.39) compared to TD children (8.77 ± 0.79). Furthermore, SC distribution across fields was different (p < 0.05) with increased percentage of SC in fields being solitary cells (p < 0.01) in children with CP. Quantification of SC number in situ, without any other tissue manipulation confirms children with spastic CP have a reduced number. This stem cell loss may, in part, explain impaired muscle growth and apparent decreased responsiveness of CP muscle to exercise.
Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California.|Department of Veterans Affairs Medical Center, San Diego, California.
Sudarshan
S
Dayanidhi
Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California.
Peter B
PB
Dykstra
Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California.
Vera
V
Lyubasyuk
Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, ON, Canada.
Bryon R
BR
McKay
Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California.|Department of Orthopaedics, Rady Children's Hospital, San Diego, La Jolla, California.
Henry G
HG
Chambers
Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California.|Department of Veterans Affairs Medical Center, San Diego, California.|Department of Bioengineering, University of California, San Diego, California.
Richard L
RL
Lieber
D000293:Adolescent; D002547:Cerebral Palsy / Q000150:complications*; D002648:Child; D003286:Contracture / Q000209:etiology / Q000473:pathology*; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000473:pathology*; D008297:Male; D032496:Satellite Cells, Skeletal Muscle
cerebral palsy; contractures; muscle stem cells; myofiber area; satellite cells