PTHrP, PTHr, and FGFR3 are involved in the process of endochondral ossification in human osteophytes.
To elucidate the process of endochondral ossification in human osteophytes we have studied the expression of parathyroid hormone-related protein (PTHrP), its receptor (PTHr), and fibroblast growth factor receptor 3 (FGFR3). Osteophytes from patients undergoing total knee replacement ( n=13), and fetal growth plate cartilages ( n=4) were processed for safranin O staining and immunohistochemistry. Chondrocytes and their matrix were preferentially stained for PTHrP in the middle and deep zones of the osteophytes examined. Ossified areas did not show a positive staining. In fetal joints the cartilaginous surface and the perichondrium as well as the osteoblasts in the trabecular bone were positive. PTHr was expressed at large in chondrocytes and osteoblasts of all osteophytes and fetal joints. Cells of the perichondrium were also positive. The FGFR3 antibody stained only single chondrocytes in some osteophytes, and groups of cells in others. In fetal samples, chondrocytes of the proliferating and the hypertrophic zone showed staining for FGFR3. This is the first report on the expression of PTHrP, PTHr, and FGFR3 in human osteophytes. As in fetal joints these mediators might regulate proliferation and differentiation of chondrocytes playing an important role in osteo(chondro)phyte growth.
Huch
Klaus
K
Department of Orthopaedics, University of Ulm, Oberer Eselsberg 45, 89081 Ulm, Germany. klaus.huch@medizin.uni-ulm.de
Kleffner
Sandra
S
Stöve
Johannes
J
Puhl
Wolfhart
W
Günther
Klaus-Peter
KP
Brenner
Rolf Erwin
RE
D000368:Aged; D002358:Cartilage, Articular / Q000196:embryology / Q000378:metabolism*; D019902:Chondrocytes / Q000378:metabolism; D005865:Gestational Age; D006132:Growth Plate / Q000196:embryology / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000378:metabolism*; D010006:Osteoblasts / Q000378:metabolism; D044162:Parathyroid Hormone-Related Protein / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases; D051498:Receptor, Fibroblast Growth Factor, Type 3; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000378:metabolism*; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism*
D044162:Parathyroid Hormone-Related Protein; D044168:Receptor, Parathyroid Hormone, Type 1; D017468:Receptors, Fibroblast Growth Factor; C496365:FGFR3 protein, human; D011505:Protein-Tyrosine Kinases; D051498:Receptor, Fibroblast Growth Factor, Type 3