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Fibrosis, low vascularity, and fewer slow fibers after rotator‐cuff injury
Author(s) -
Gigliotti Deanna,
Xu Mark C.,
Davidson Michael J.,
Macdonald Peter B.,
Leiter Jeff R.S.,
Anderson Judy E.
Publication year - 2017
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.25388
Subject(s) - vascularity , rotator cuff , medicine , fibrosis , surgery , pathology
Rotator‐cuff injury (RCI) represents 50% of shoulder injuries, and prevalence increases with age. Even with successful tendon repair, muscle and joint function may not return. Methods To explore the dysfunction, supraspinatus and ipsilateral deltoid (control) muscles were biopsied during arthroscopic RCI repair for pair‐wise histological and protein‐expression studies. Results Supraspinatus showed fiber atrophy ( P < 0.0001), fibrosis (by Sirius Red, P = 0.05), reduced vascular density ( P < 0.001), and a lower proportion of slow fibers ( P < 0.0001) compared with the ipsilateral control muscle. There were also higher levels of atrogin‐1 ( P = 0.05), vascular endothelial growth factor (VEGF, P < 0.01), and dystrophin ( P < 0.008, relative to fiber diameter) versus control. Conclusions Adaptive changes in vascular endothelial growth factor and dystrophin were likely associated with reduced vascular supply, fatigue resistance, and fibrosis, accompanied by disuse atrophy from mechanical unloading of supraspinatus after tendon tear. Treatment to promote growth and vascularity in atrophic supraspinatus muscle may help improve functional outcome after surgical repair. Muscle Nerve 55: 715–726, 2017