ESPE Yearbook of Paediatric Endocrinology

To read the full abstract: Sci Rep. 2019 Apr 30; 9(1): 6691.

In recent years, improved knowledge of the metabolic risks in childhood cancer survivors (CCS) has increasingly focused research on modifiable factors and preventive strategies (1–2). It is well known that therapeutic irradiation can cause detrimental changes in body composition, but it is still unknown whether the specific effects of radiation on skeletal muscle are influenced by physiological factors, such as obesity and exercise training.

This study evaluated, on a mouse model, the late effects of diet-induced obesity and exercise training on irradiated skeletal muscle morphology and cellular dynamics. Forty mice were divided into control and high-fat-diet groups with or without exercise training; all mice were then exposed to total body irradiation. After continuing for another 4 weeks in their intervention group, tissue collection was performed. Diet-induced obesity resulted in increased muscle fibrosis, while obesity and exercise training both increased muscle adiposity. Exercise training enhanced myofibre cross-sectional area and the number of satellite cells (myogenic stem cells that contribute to muscle growth and/or repair, and are depleted in irradiated skeletal muscle) committed to the myogenic lineage, independently of diet. High-fat-diet group demonstrated an increase in the expression of the inflammatory marker p-NFκB, regardless of exercise training.

This study suggests that radiation exposure during muscle development induces long-term impairment of skeletal muscle health, which may contribute to reduced quality of life in irradiated CCS. The findings need to be confirmed, as muscle cell dynamics were analyzed at a single post-radiation time point, which does not allow to document pre-radiation differences and the long-term evolution of muscle damage.

References: 1. Srivastava R, Batra A, Dhawan D, Bakhshi S. Association of energy intake and expenditure with obesity: A cross-sectional study of 150 pediatric patients following treatment for leukemia. Pediatr Hematol Oncol. 2017; 34: 29–35.

2. Slater ME, Ross JA, Kelly AS, Dengel DR, Hodges JS, Sinaiko AR, Moran A, Lee J, Perkins JL, Chow LS, Baker KS, Steinberger J. Physical activity and cardiovascular risk factors in childhood cancer survivors. Pediatr Blood Cancer 2015; 62: 305–310.