Hypophosphatemia leads to rickets and osteomalacia, the latter of which results in decreased biomechanical integrity of bones, accompanied by poor fracture healing. Impaired phosphate-dependent apoptosis of hypertrophic chondrocytes is the molecular basis for rickets. However, the underlying pathophysiology of impaired fracture healing has not been characterized previously. To address the role ...

3 INSERTION OF THE CORACO-ACROMIAL LIGAMENT IN THE ACROMION: HISTOLOGIC STUDY OF THE DEGENERATIVE ENDOCHONDRAL OSSIFICATION O. Lech, MD, J. Barbosa, MD, A. Gailit, Jr, MD, and A. Marcolan, MD; Instituto de Ortopedia e Traumatologia de Passo Fundo, RS, Brazil The authors evaluate the incidence of degenerative endochondral ossification at the insertion of the coraco-acromial ligament (CAL) in the...

Heat shock protein 47 kDa (Hsp47) is considered as a molecular chaperone essential for the correct folding of type I and type IV procollagen in the ER. However, the function of Hsp47 for other types of procollagen and its importance for chondrogenesis have never been elucidated. To examine the function of Hsp47 in cartilage formation and endochondral ossification, we conditionally inactivated t...

Unregulated FGF signaling affects endochondral ossification and long bone growth, causing several genetic forms of human dwarfism. One major mechanism by which FGFs regulate endochondral bone growth is through their inhibitory effect on chondrocyte proliferation. Because mice with targeted mutations of the retinoblastoma (Rb)-related proteins p107 and p130 present severe endochondral bone defec...

Down syndrome (DS) is a common genetic disorder that occurs in approximately 1 out of every 750 live births. DS phenotypes include cognitive deficits, altered craniofacial features, muscle hypotonia, heart defects, and abnormal bone structure. The Ts65Dn mouse model is the most common organismal model used to study DS phenotypes. This model exhibits a number of phenotypic traits comparable to t...

In direct fracture healing no or just a minimal amount of external callus is formed. The strain in the fracture gap is low enough to allow direct bone formation. This can only occur in anatomically reconstructed fractures that are rigidly stabilized. In indirect fracture healing, new bone is formed by transformation of fibrous tissue or cartilaginous tissue (endochondral bone formation). This o...

During endochondral bone formation, chondrocytes pass through several distinct stages of differentiation, including cell division and hypertrophy. The terminal step in this process, chondrocyte apoptosis, is followed by vascular invasion and bone formation on cartilage remnants. Chondrocytes in culture have been shown to express and release high levels TGF-beta 2. We report here that the apopto...

Endochondral bone formation was induced in postnatal rats by implantation of demineralized rat bone matrix. Corresponding control tissue was generated by implanting inactive extracted bone matrix, which did not induce bone formation. At various times, implants were removed and sequentially extracted with guanidine hydrochloride, and then EDTA and guanidine hydrochloride. Transforming growth fac...

Novel strategies are urgently required to facilitate regeneration of entire bones lost due to trauma or disease. In this study, we present a novel framework for the regeneration of whole bones by tissue engineering anatomically shaped hypertrophic cartilaginous grafts in vitro that subsequently drive endochondral bone formation in vivo. To realize this, we first fabricated molds from digitized ...