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Cranial Sutures (cranial + suture)
Selected AbstractsType I collagen is a genetic modifier of matrix metalloproteinase 2 in murine skeletal developmentDEVELOPMENTAL DYNAMICS, Issue 6 2007Mikala Egeblad Abstract Recessive inactivating mutations in human matrix metalloproteinase 2 (MMP2, gelatinase A) are associated with syndromes that include abnormal facial appearance, short stature, and severe bone loss. Mmp2,/, mice have only mild aspects of these abnormalities, suggesting that MMP2 function is redundant during skeletal development in the mouse. Here, we report that Mmp2,/, mice with additional mutations that render type I collagen resistant to collagenase-mediated cleavage to TCA and TCB fragments (Col1a1r/r mice) have severe developmental defects resembling those observed in MMP2 -null humans. Composite Mmp2,/,;Col1a1r/r mice were born in expected Mendelian ratios but were half the size of wild-type, Mmp2,/,, and Col1a1r/r mice and failed to thrive. Furthermore, composite Mmp2,/,;Col1a1r/r animals had very abnormal craniofacial features with shorter snouts, bulging skulls, incompletely developed calvarial bones and unclosed cranial sutures. In addition, trabecular bone mass was reduced concomitant with increased numbers of bone-resorbing osteoclasts and osteopenia. In vitro, MMP2 had a unique ability among the collagenolytic MMPs to degrade mutant collagen, offering a possible explanation for the genetic interaction between Mmp2 and Col1a1r. Thus, because mutations in the type I collagen gene alter the phenotype of mice with null mutations in Mmp2, we conclude that type I collagen is an important modifier gene for Mmp2. Developmental Dynamics 236:1683,1693, 2007. © 2007 Wiley-Liss, Inc. [source] Apert syndrome with glucose-6-phosphate dehydrogenase deficiency: a case reportINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 3 2006G. TOSUN Summary., Apert syndrome is characterized by midface hypoplasia, syndactyly of the hands and feet, proptosis of eyes, steep and flat frontal bones, and premature union of cranial sutures. Maxillary hypoplasia, deep palatal vault, anterior open bite, crowding of the dental arch, severely delayed tooth eruption, and dental malocclusion are the main oral manifestations of this syndrome. In this report, a case of Apert syndrome with glucose-6-phosphate dehydrogenase (G6PD) deficiency is presented. The patient, a 4-year-old male and the fourth child of healthy parents, was admitted to our department because of delayed tooth eruption. He had all the cardinal symptoms of the Apert syndrome. Clinical examination revealed that primary centrals, canines and first molars erupted; however, primary second molars and laterals had not erupted. The patient had no dental caries. Preventive treatments were applied, and subsequently, the patient was taken to long-term follow up. [source] Cell proliferation and osteogenic differentiation of growing pig cranial suturesJOURNAL OF ANATOMY, Issue 3 2007Zongyang Sun Abstract Bone growth at the cranial sutures relies on proliferation of osteogenic progenitor cells and/or differentiation of osteoblasts. The current study was undertaken to assess these events in relation to suture growth and fusion. A total of 21 pigs, divided into three age groups (0.5,1.5 months, 3,4 months and 5,7 months), were used for immunohistochemical evaluation of cell proliferation (BrdU) and osteogenic differentiation (Cbfa1/Runx2) in the interfrontal and interparietal sutures. Proliferation and osteogenic differentiation were both more prominent near the bone fronts than in the central zone. With age, both proliferation and osteogenic differentiation diminished. Proliferation ceased on the endocranial (dura mater) side by the age of 3,4 months. Proliferation on the pericranial side was accompanied by active bone formation and initiation of suture fusion from this side. In conclusion, (1) decreased suture bone growth with age reflects decreased cell proliferation and probably also osteogenic differentiation, and (2) suture fusion occurs from the pericranial side where activity remains relatively high. [source] Noggin Inhibits Postoperative Resynostosis in Craniosynostotic Rabbits,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2007Gregory M Cooper PhD Abstract Inhibition of bone formation after surgery to correct craniosynostosis would alleviate the need for secondary surgeries and decrease morbidity and mortality. This study used a single dose of Noggin protein to prevent resynostosis and improve postoperative outcomes in a rabbit model of craniosynostosis. Introduction: Craniosynostosis is defined as the premature fusion of one or more of the cranial sutures, which causes secondary deformations of the cranial vault, cranial base, and brain. Current surgical intervention involves extirpation of the fused suture to allow unrestricted brain growth. However, resynostosis of the extirpated regions often occurs. Several bone morphogenetic proteins (BMPs), well-described inducers of ossification, are involved in bone healing. This study tested the hypothesis that a postoperative treatment with Noggin, an extracellular BMP inhibitor, can inhibit resynostosis in a rabbit model of human familial nonsyndromic craniosynostosis. Materials and Methods: Thirty-one New Zealand white rabbits with bilateral coronal suture synostosis were divided into three groups: (1) suturectomy controls (n = 13); (2) suturectomy with BSA in a slow-resorbing collagen vehicle, (n = 8); and (3) suturectomy with Noggin in a slow-resorbing collagen vehicle (n = 10). At 10 days of age, a 3 × 15-mm coronal suturectomy was performed. The sites in groups 2 and 3 were immediately filled with BSA-loaded gel or Noggin-loaded gel, respectively. Serial 3D-CT scan reconstructions of the defects and standard radiographs were obtained at 10, 25, 42, and 84 days of age, and the sutures were harvested for histological analysis. Results: Radiographic analysis revealed that Noggin-treated animals had significantly greater coronal suture marker separation by 25 days and significantly greater craniofacial length at 84 days of age compared with controls. 3D-CT analysis revealed that Noggin treatment led to significantly greater defect areas through 84 days and to increased intracranial volumes at 84 days of age compared with other groups. Histological analysis supported CT data, showing that the untreated and BSA-treated groups had significant healing of the suturectomy site, whereas the Noggin-treated group had incomplete wound healing. Conclusions: These data support our hypothesis that inhibition of BMP activity using Noggin may prevent postoperative resynostosis in this rabbit model. These findings also suggest that Noggin therapy may have potential clinical use to prevent postoperative resynostosis in infants with craniosynostosis. [source] Transforming growth factor- ,3 (Tgf- ,3) down-regulates Tgf- , receptor type I (T,r-I) during rescue of cranial sutures from osseous obliterationORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 1 2002LA Opperman Abstract Appropriate biochemical regulation of intramembranous bone growth from sutures is necessary to achieve correct craniofacial morphology. Failure to form sutures (agenesis) or to maintain sutures in their unossified state (craniosynostosis) can result in severe facial dysmorphology. Several factors such as Twist, Msx2, fibroblast growth factors (Fgfs), bone morphogenetic proteins (Bmps) and transforming growth factors- , (Tgf- ,s) regulate suture patency, likely by interacting with one another. Tgf- ,2 and Tgf- ,3 use the same cell surface receptors, yet have opposite effects on suture patency, cellular proliferation and apoptosis within the suture. One possible mechanism by which Tgf- ,3 rescues sutures from obliteration is by regulating the ability of suture cells to respond to Tgf- ,2. As Tgf- ,3 does not regulate protein levels of Tgf- ,2 in sutures, Tgf- ,3 could regulate tissue responsiveness to Tgf- ,2 by regulating Tgf- ,2 access to receptors. Tgf- ,3 is a more potent competitor than Tgf- ,2 for cell surface receptors, so it is proposed that Tgf- ,3 binds to and down-regulates Tgf- , receptor type I (T,r-I) expression by suture cells. This down-regulation would limit the ability of cells to respond to all Tgf- ,s, including Tgf- ,2. To test this hypothesis, an in vitro culture model was used in which fetal rat sutures either remain patent or are induced to fuse when cultured in the presence or absence of dura mater, respectively. Tgf- ,3 was added to cultured calvaria and changes in the number of receptor positive cells within the suture were established. Data were compared with that seen in control sutures and in normal sutures in vivo. It was found that the numbers of cells expressing T,r-I within the suture matrix increased over time in sutures remaining patent. Osteoblastic cells lining the bone fronts on either side of sutures were T,r-I positive during early morphogenesis, but these numbers declined as sutures fused, both in vivo and in vitro. Addition of Tgf- ,3 to calvaria in culture decreased the number of T,r-I expressing cells in both fusing and non-fusing sutures, with dramatic decreases in the numbers of osteoblasts expressing T,r-I. [source] | |||||||||||||