Tohoku J. Exp. Med., 2018 January, 244(1)

Retained Myogenic Potency of Human Satellite Cells from Torn Rotator Cuff Muscles Despite Fatty Infiltration

MASASHI KOIDE,¹ YOSHIHIRO HAGIWARA,¹ MASAHIRO TSUCHIYA,² MAKOTO KANZAKI,³ HIROYASU HATAKEYAMA,^3,4 YUKINORI TANAKA,⁵ TAKASHI MINOWA,⁶ TARO TAKEMURA,⁶ AKIRA ANDO,¹ TAKUYA SEKIGUCHI,¹ YUTAKA YABE¹ and EIJI ITOI¹

¹Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
²Tohoku Fukushi University, Sendai, Miyagi, Japan
³Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, Japan
⁴Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Miyagi, Japan
⁵Department of Oral Immunology, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
⁶National Institute for Materials Science, Tsukuba, Ibaraki, Japan

Rotator cuff tears (RCTs) are a common shoulder problem in the elderly that can lead to both muscle atrophy and fatty infiltration due to less physical load. Satellite cells, quiescent cells under the basal lamina of skeletal muscle fibers, play a major role in muscle regeneration. However, the myogenic potency of human satellite cells in muscles with fatty infiltration is unclear due to the difficulty in isolating from small samples, and the mechanism of the progression of fatty infiltration has not been elucidated. The purpose of this study was to analyze the population of myogenic and adipogenic cells in disused supraspinatus (SSP) and intact subscapularis (SSC) muscles of the RCTs from the same patients using fluorescence-activated cell sorting. The microstructure of the muscle with fatty infiltration was observed as a whole mount condition under multi-photon microscopy. Myogenic differentiation potential and gene expression were evaluated in satellite cells. The results showed that the SSP muscle with greater fatty infiltration surrounded by collagen fibers compared with the SSC muscle under multi-photon microscopy. A positive correlation was observed between the ratio of muscle volume to fat volume and the ratio of myogenic precursor to adipogenic precursor. Although no difference was observed in the myogenic potentialbetween the two groups in cell culture, satellite cells in the disused SSP muscle showed higher intrinsic myogenic gene expression than those in the intact SSC muscle. Our results indicate that satellite cells from the disused SSP retain sufficient potential of muscle growth despite the fatty infiltration.

keywords —— arthroscopic surgery; fatty infiltration; muscle; rotator cuff tear; satellite cell

© 2018 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2018, 244, 15-24

Correspondence: Yoshihiro Hagiwara, Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan.

e-mail: hagi@med.tohoku.ac.jp