HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology

 

Review

What understanding tendon cell differentiation can teach us about pathological tendon ossification

D. Magne and C. Bougault

UMR CNRS 5246, University Claude Bernard-Lyon 1, University of Lyon, Institute for Molecular and Supramolecular Chemistry and Biochemistry, Villeurbanne, France

Offprint requests to: C. Bougault, UMR CNRS 2546, Villeurbanne France, University Claude Bernard-Lyon 1, University of Lyon, Institute for Molecular and Supramolecular Chemistry and Biochemistry, Villeurbanne, France. e-mail: carole.bougault@univ-lyon1.fr


Summary. Tendons are the structures that attach muscles to bones and transmit mechanical forces. Tendon cells are composed of mature tenocytes and a rare population of tendon stem cells. Both cell types ensure homeostasis and repair of tendon extracellular matrix to guarantee its specific mechanical properties. Moreover, tendon cells seem to present a marked potential for trans-differentiation, predominantly into the chondrocyte and osteoblast lineages. In this review article, we first present chronic tendon pathologies associated with abnormal ossification, such as spondyloarthritis and calcifying tendinopathy, and discuss how tendon cell differentiation and trans-differentiation may participate in these diseases. We moreover present the factors known to influence tendon cell differentiation and trans-differentiation, with a particular emphasis on extracellular environment, mechanical stimulation and several soluble factors that can tip the balance toward one or another lineage. A better understanding of the neglected tendon cell biology may be extremely useful to understand the pathological mechanisms of spondyloarthritis and calcifying tendinopathy. Histol Histopathol 30, 901-910 (2015)

Key words: Tenocytes, Tendom stem cells, Trans-differentiation, Pathological ossification

DOI: 10.14670/HH-11-614