IGF2 expression and β-catenin levels are increased in Frozen Shoulder Syndrome

Frozen Shoulder Syndrome is a fibrosis of the shoulder joint capsule that is clinically associated with Dupuytren's disease, a fibrosis of the palmar fascia. Little is known about any commonalities in the pathophysiology of these connective tissue fibroses. β-catenin, a protein that transactivates gene expression, and levels of IGF2 mRNA, encoding insulin-like growth factor-II, are elevated in Dupuytren's disease. The aim of this study was to determine if correlating changes in β-catenin levels and IGF2 expression are evident in Frozen Shoulder Syndrome.

Tissue from patients with Frozen Shoulder Syndrome and rotator cuff tear were obtained during shoulder arthroscopies. Total protein extracts were prepared from tissue aliquots and β-catenin immunoreactivity was assessed by Western immunoblotting. In parallel, primary fibroblasts were derived from these tissues and assessed for IGF2 expression by quantitative PCR.

β-catenin levels were significantly increased in Frozen Shoulder Syndrome relative to rotator cuff tear when assessed by Western immunoblotting analyses. IGF2 mRNA levels were significantly increased in primary fibroblasts derived from frozen shoulder syndrome tissues relative to fibroblasts derived from rotator cuff tissues.

As in Dupuytren's disease, β-catenin levels and IGF2 expression are elevated in Frozen Shoulder Syndrome. These findings support the hypothesis that these connective tissue fibroses share a common pathophysiology.