Reduced satellite cell number in situ in muscular contractures from children with cerebral palsy

Abstract

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 ¼ 11) were labeled with fluorescent antibodies for Pax7 (SC transcriptional marker), laminin (basal lamina), and 4 0 ,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 AE 0.39) compared to TD children (8.77 AE 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. ß

Reduced skeletal muscle satellite cell number alters muscle morphology after chronic stretch but allows limited serial sarcomere addition

“…This is a smaller reduction than was previously reported, raising the possibility that remaining SCs compensated for depletion and were sufficient to allow for quantitatively normal serial sarcomerogenesis. However, this incomplete knockdown of SC is similar to the SC number observed in muscle of children with CP, where SCs are depleted by 60–70% . Thus, we believe that the findings we present are of clinical relevance despite incomplete SC depletion.…”

Gastrocnemius muscle–tendon interaction during walking in typically-developing adults and children, and in children with spastic cerebral palsy

“…In fact, Dayanidhi et al (2015) showed that the number of satellite cells in the gracilis muscle of children with cerebral palsy (expressed as number per 100 myofibers) was reduced by 70% when compared to their age-matched peers. So, it is possible that in children with SCP, muscles damaged by eccentric lengthening may not have the opportunity or resources to recover fully, leading to irreversible and deleterious changes in muscle quality and further weakness.…”

Skeletal muscle satellite cells: Mediators of muscle growth during development and implications for developmental disorders

“…However, as noted, children with CP have ECM abnormalities that may systematically bias flow cytometry results in that it may be more difficult to extract SCs from CP muscle. To test this idea, we used the more labor‐intensive in situ immunohistochemistry method to quantify SCs using antibodies for SCs (anti‐Pax7), the basal lamina (anti‐laminin), and a nuclear stain (4',6‐diamidino‐2‐phenylindole, or DAPI). By systematically sampling large volumes of tissue, we quantified SC number in situ without significant tissue manipulation (Fig.…”