Skeletal muscle fibre morphology in childhood—insights into myopenia in pediatric liver disease

Abstract

Myopenia (reduced skeletal muscle [SM]) is common in children with end-stage liver disease (ESLD) and suboptimal nutritional status pre- and post-liver transplantation (LTx). Myopenia may result in altered SM morphology (changes in muscle fibre size and types [type I vs. II proportions]) contributing to adverse outcomes and deficits in muscle strength/functionality. Understanding how SM morphology changes in healthy children with age and the potential impact of ESLD on SM morphology offers insight into the effectiveness of rehabilitation strategies for children with ESLD at risk for myopenia. Literature searches in PubMed, Scopus, and Web of Science identified studies examining SM morphology in healthy children and in ESLD. Muscle fibre size increases with age in healthy children. Type I fibres are more prevalent in childhood, whereas type II fibres increase post-puberty. Preliminary evidence indicates that adults with ESLD have reduced muscle fiber size with type II fibre atrophy. No data are available for pediatric ESLD. SM morphology changes with age and may be impacted by the negative physical and metabolic insults associated with ESLD and malnutrition. Take-home message Skeletal muscle morphology in healthy children changes with age. Liver disease may preferentially affect type II fibres in adults with end-stage liver disease (ESLD). More research is needed on the effects of ESLD on muscle morphology in children.