title: Development of the supraspinatus tendon-to-bone insertion: localized expression of extracellular matrix and growth factor genes.
abstract: The adult healing response of the rotator cuff tendon-to-bone insertion site differs from the ordered process of insertion site development. Healing is characterized by disorganized scar and a lack of fibrocartilage formation, in contrast to the well organized fibrocartilaginous transition which forms during the normal development of the tendon-to-bone insertion. The purpose of this study was to localize the expression of a number of extracellular matrix and growth factor genes during insertion site development in order to guide future strategies for augmenting adult rotator cuff healing. The rotator cuff was morphologically distinct at 13.5 dpc (days postconception). Neo-tendon was evident as a condensation of cells adjacent to bone. The interface between tendon and bone did not form into a mature fibrocartilaginous insertion until 21-days postnatally, based upon the appearance of four distinct zones with a mineralized humeral head. Fibroblasts of the supraspinatus tendon expressed type I collagen at all timepoints. Type II collagen was first expressed by chondrocytes in the fibrocartilage and mineralized fibrocartilage at 7 days and persisted in the mineralized fibrocartilage at 56 days. Type X collagen was first expressed by the chondrocytes in the mineralized fibrocartilage at 14 days and persisted in the mineralized fibrocartilage at 56 days. A shift from TGF-beta3 to TGF-beta1 expression occurred at 15.5 dpc.
authors.affiliation: Washington University Orthopaedics, Barnes-Jewish Hospital, Campus Box 8233, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA. galatzl@wustl.edu
authors.forename: Leesa
authors.initials: L
authors.lastname: Galatz
authors.forename: Stefan
authors.initials: S
authors.lastname: Rothermich
authors.forename: Kristin
authors.initials: K
authors.lastname: VanderPloeg
authors.forename: Bryan
authors.initials: B
authors.lastname: Petersen
authors.forename: Linda
authors.initials: L
authors.lastname: Sandell
authors.forename: Stavros
authors.initials: S
authors.lastname: Thomopoulos
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002113:Calcification, Physiologic / Q000502:physiology; D024121:Collagen Type X / Q000235:genetics / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D011247:Pregnancy; D017006:Rotator Cuff / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D012785:Shoulder Joint / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D014945:Wound Healing / Q000502:physiology
chemical_list: D024121:Collagen Type X; D016212:Transforming Growth Factor beta