Pathologic gene expression in adhesive subacromial bursae of human shoulder

An adhesion of the subacromial bursa in the shoulder causes pain during joint motion and restricts the range of motion of the glenohumeral joint. To understand the biologic features of an adhesion, the gene expressions in adhesive subacromial bursa were analyzed by quantitative real-time reverse transcriptase-polymerase chain reaction. The gene expressions in adhesive subacromial bursae were approximately threefold to fourfold greater than those in nonadhesive bursae for the genes for Type I and Type III procollagens, CD34 antigen in vascular endothelium, hyaluronan synthase-3, and interferon-gamma. The gene expression of interleukin-8 was predominant in adhesive bursa. The gene expressions of hyaluronan synthase-1, hyaluronan synthase-2, and interleukin-10 which is an antiadhesive cytokine were predominant in nonadhesive bursae. Chromatography analysis revealed that a hyaluronan, of which molecular weight was more than 100 kDa, was present in the cavity of nonadhesive subacromial bursae. It is suggested that pathologic fibrosis and vascularization are maintained by the presence of interferon-gamma and interleukin-8 in adhesive subacromial bursae and that high molecular weight hyaluronan or interleukin-10 plays a role for antiadhesion.