Analysis of Human Tendinopathy Gene Expression

Chronic tendon injuries, also known as tendinopathy, are common among professional and recreational athletes. These injuries result in a significant amount of morbidity and health care expenditure and yet little is known about the molecular mechanism leading to tendinopathy. We have used histological evaluation and molecular profiling to determine the gene expression changes in 23 human patients undergoing surgical procedures for the treatment of chronic tendinopathy. Diseased tendons have altered extracellular matrix, fiber disorientation, increased cellular content and vasculature and the absence of inflammatory cells. Global gene expression profiling identified 1783 transcripts with significant different expression patterns in the diseased tendons. Global pathway analysis further suggests altered expression of extracellular matrix proteins and the lack of an appreciable inflammatory response. We have identified pathways and genes regulated in tendinopathy samples that will help contribute to the understanding of the disease towards the development of novel therapeutics. A prospective study was initiated to collect tissue from patients undergoing surgery as standard of care for tendinopathy. Biopsies (~3mm^3) of diseased tendons as well as a section of grossly normal appearing tendon were collected from 23 patients. Written informed consent was obtained from all patients prior to any study related procedure.