DOS 2017

· DOS Abstracts

Muscle inflammation following supraspinatus tears

Lars Henrik Frich, Kate Lykke Lambertsen, Allan Steensballe, Henrik

Daa Schrøder

Orthopadics, Odense UniversitetsHospital; Clinical research, University of

Southern Denmark; Health Science and Technology, Aalborg University; Pathol-

ogy, Odense university Hospital

Background:

Rotator cuff (RC) lesions are one of the most common condi-

tions affecting the shoulder. The etiology of RC diseases is multifactorial but the

supraspinatus (SS) tendon is particularly vulnerable to become lesioned. In pa-

tients with RC tears, increased numbers of inflammatory cells have been dem-

onstrated in the inflamed synovial tissue. Recent studies have suggested that

also the RC muscles become inflamed after RC tears and animal models suggest

that acute inflammation plays a detrimental role in chronic muscle damage fol-

lowing RC tears.

Purpose / Aim of Study:

The aim of this study was to characterize inflamma-

tion in humans suffering from a RC tear

Materials and Methods:

Tissue samples were taken from the RC tissues at

the time of surgery in 9 patients scheduled for surgery. Mean age was 58 years

(40-61) years. All patients had a MRI validated SS tear. Control biopsies were

obtained from the deltoid muscle. We used multiplex analysis, proteomics, his-

tological and immunohistochemical analyses to study the inflammatory profiles

of SS muscle and tendon, deltoid muscle and bursa.

Findings / Results:

Multiplex analysis demonstrated differential expression

levels of several matrix metalloproteinases. Also several inflammatory media-

tors were differentially expressed between RC tissues. Immuno-histochemical

analyses of SS muscle demonstrated the presence of CD68+ macrophages, and

CD3+ and CD8+ T cells. Proteomic analysis demonstrated the presence of in-

flammatory related proteins in the SS tendon and SS muscle.

Conclusions:

We have shown that not only the tendon becomes inflamed fol-

lowing RC tendon tears but also the SS muscle shows sign of inflammation.

Chronic inflammation differs between tendon and muscle and between mus-

cles, which suggests that the pathophysiological mechanisms taking place in RC

muscles may be a major contributor to RC disease.

No conflicts of interest reported

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