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Bone Formation Processes (bone + formation_process)
Selected AbstractsEarly cortical bone healing around loaded titanium implants: a histological study in the rabbitCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2009Elke Slaets Abstract Objectives: To identify the role of immediate implant loading on the early phases of the bone healing responses. Material and methods: Implants were placed in rabbit tibial diaphyses and left to heal for 3, 7, 14, 28 or 42 days. Half of the animals received an immediate loading protocol of 2.2 N at 3 Hz for 1800 cycles and 5 days/week, whereas the others served as unloaded controls. Histological assessment was combined with histomorphometrical measurements. Results: At early time-points, an endosteal and periosteal new bone formation was found, while the cortex itself contained damaged osteocytes. At later time-points, new bone formation was also found at the cortical level itself. Differences between groups were found mainly in this new bone formation process, with larger reactions for the endosteal and periosteal bone in the loaded group after 28 and 42 days, respectively. At the end-point of the experiment, bone formation at the cortical level was reduced in the loaded group compared with the control group. Conclusions: These results show that the immediate loading protocol caused no differences in the sequential events leading to osseointegration in cortical bone. However, the processes of new bone formation originating from the endosteum and the periosteum lasted longer compared with the unloaded controls. [source] Tissue response to titanium implantation in the rat maxilla, with special reference to the effects of surface conditions on bone formationCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2003Masaki Shirakura Abstract: Tissue responses to titanium implantation with two different surface conditions in our established implantation model in rat maxillae were investigated by light and transmission electron microscopy and by histochemistry for tartrate-resistant acid phosphatase (TRAPase) activity. Here we used two types of implants with different surface qualities: titanium implants sandblasted with Al2O3 (SA-group) and implants coated with hydroxyapatite (HA-group). In both groups, bone formation had begun by 5 days postimplantation when the inflammatory reaction had almost disappeared in the prepared bone cavity. In the SA-group, however, the bone formation process in the bone cavity was almost identical to that shown in our previous report using smooth surfaced implants (Futami et al. 2000): new bone formation, which occurred from the pre-existing bone toward the implant, was preceded by active bone resorption in the lateral area with a narrow gap, but not so in the base area with a wide gap. In the HA-group, direct bone formation from the implant toward the pre-existing bone was recognizable in both lateral and base areas. Many TRAPase-reactive cells were found near the implant surface. On the pre-existing bone, new bone formation occurred with bone resorption by typical osteoclasts. Osseointegration around the implants was achieved by postoperative day 28 in both SA- and HA-groups except for the lateral area, where the implant had been installed close to the cavity margin. These findings indicate that ossification around the titanium implants progresses in different patterns, probably dependent on surface properties and quality. Résumé Les réponses tissulaires à l'implantation du titane avec deux conditions de surfaces différentes dans le maxillaire du rat ont étéétudiées par microscopie optique et électronique à transmission et par histochimie pour l'activité de l'acide phosphatase résistant au tartrate (TRAPase). Deux types d'implants avec différentes qualité de surface ont été utilisés : des implants en titane sablés par du AL2O3 (groupe SA) et des implants couverts par de l'hydroxyapatite (groupe HA). Dans les deux groupes la formation osseuse avait démarré cinq jours après l'implantation, lorsque la réaction inflammatoire avait presque disparue de la cavité osseuse préparée. Cependant, dans le groupe SA le processus de formation osseuse de la cavité osseuse était quasi identique à celle montrée dans un rapport précédent utilisant des implants à surface lisse (Futami et al., 2000) : la néoformation osseuse qui démarre de l'os préexistant vers l'implant, était précédée par une résorption osseuse active dans l'aire latérale avec une brèche étroite, mais pas dans l'aire de base avec un espace large. Dans le groupe HA, une formation osseuse directe de l'implant vers l'os préexistant était reconnaissable tant dans les aires latérales qu'au niveau de la base. Beaucoup de cellules réactives au TRAPase ont été trouvées près de la surface de l'implant. Sur l'os préexistant une néoformation osseuse est apparue avec une résorption osseuse par des ostéoclastes typiques. L'ostéoïntégration autour des implants a été achevée au jour 28 après l'opération tant dans le groupe SA que HA excepté pour l'aire latérale où l'implant avait été inséré près du rebord de la cavité. Ces découvertes indiquent que l'ossification autour des implants en titane progresse de manière différente dépendant probablement de la qualité et des propriétés de surface. Zusammenfassung Die Gewebsantwort auf implantiertes Titan in einem Rattenoberkiefer. Spezielles Augenmerk auf die Einflüsse der Oberflächenbeschaffenheit auf die Knochenbildung. An unserem etablierten Implantationsmodell am Rattenoberkiefer wurde die Gewebsantwort nach der Titanimplantation von zwei Prüfkörpern mit verschiedener Oberfläche mit Hilfe der Licht- und Transmissionselektronenmikroskopie, sowie mittels Histochemie zum Aktivitätsnachweis der tartratresitenten sauren Phosphatase (TRAPase) untersucht. Wir benutzten hier zwei Implantattypen mit verschiedenen Oberflächen: Mit Al2O3 sandgestrahlte Titanimplantate (SA-Gruppe) und mit Hydroxylapatit beschichtete Implantate (HA-Gruppe). Bei beiden Gruppen begann die Knochenbildung 5 Tage nach der Implantation, sobald die Entzündungsreaktion im präparierten Knochenbett am verschwinden war. In der SA-Gruppe aber, zeigte sich im präparierten Implantatbett ein beinahe gleicher Knochenbildungsvorgang, wie in unseren früheren Berichten für glatte Implantatoberflächen beschrieben (Futami et al., 2000): Die vom bereits vorhandenen Knochen ausgehende Knochenneubildung gegen das Implantat hin erfolgte erst nach einer aktiven Knochenresorption im lateralen Bereich. Es entstand eine minime Spalte zwischen Knochen und Implantat, währenddem im apicalen Bereich eine breitere Spalte entstand. In der HA-Gruppe konnte man sowohl im lateralen, wie auch im apicalen Bereich eine direkt vom Implantat ausgehende Knochenbildung in Richtung des vorhandenen Knochens feststellen. In der Nähe der Implantatoberfläche fand man viele TRAPase-reaktive Zellen. Beim vorhandenen Knochen erfolgte die Knochenneubildung gleichzeitig mit der Knochenresorption durch typische Osteoklasten. Die Osseointegration rund um die Implantate herum erreichte man, ausser im lateralen Bereich gegen den Rand des Implantatbettes hin, in der SA-und der HA-Gruppe am 28igsten postoperativen Tag. Diese Ergebnisse zeigen, dass die Ossifikation um Titanimplantate in verschiedenen Mustern abläuft, wahrscheindlich in Abhängigkeit von der Oberflächeneigenschaft und -qualität. Resumen Se investigó las respuestas tisulares a la implantación con titanio con dos condiciones diferentes de superficie en nuestro modelo establecido de implantación en el maxilar de la rata por medio de microscopía óptica y electrónica de transmisión y por medio de histoquímica para la actividad de fosfatasa alcalina tartrato resistente (TRAPase). Hemos usado aquí dos tipos de implantes con diferentes calidades de superficies: Implantes de titanio pulverizados con Al2O3 (grupo-SA), e implantes cubiertos con hidroxiapatita (grupo-HA). En ambos grupos la formación de hueso comenzó a los 5 días de la implantación cuando la reacción inflamatoria hubo casi desaparecido en la cavidad ósea preparada. De todos modos, en el grupo SA, el proceso de formación de hueso en la cavidad ósea fue casi idéntico a aquel mostrado en nuestro informe previo usando implantes de superficies lisas (Futami et al., 2000): neoformación de hueso, que tuvo lugar desde el hueso preexistente hacia el implante, siendo precedida por reabsorción ósea activa en el área lateral con un espacio estrecho, pero no así en el área basal con espacio ancho. Se encontraron muchas células TRAPase reactivas cerca de la superficie del implante. En el hueso preexistente, la neoformación ósea tuvo lugar con reabsorción ósea con osteoclastos típicos. La osteointegración alrededor de los implantes se logró al día 28 tras la operación en ambos grupos SA y HA excepto para el área lateral, donde el implante se instaló cerca del margen de la cavidad. Estos hallazgos indican que la osificación alrededor de los implantes de titanio progresa con patrones diferentes, probablemente dependiendo de las propiedades y las calidades de la superficie. [source] Type V Osteogenesis Imperfecta: A New Form of Brittle Bone Disease,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2000Francis H. Glorieux Abstract Osteogenesis imperfecta (OI) is commonly subdivided into four clinical types. Among these, OI type IV clearly represents a heterogeneous group of disorders. Here we describe 7 OI patients (3 girls), who would typically be classified as having OI type IV but who can be distinguished from other type IV patients. We propose to call this disease entity OI type V. These children had a history of moderate to severe increased fragility of long bones and vertebral bodies. Four patients had experienced at least one episode of hyperplastic callus formation. The family history was positive for OI in 3 patients, with an autosomal dominant pattern of inheritance. All type V patients had limitations in the range of pronation/supination in one or both forearms, associated with a radiologically apparent calcification of the interosseous membrane. Three patients had anterior dislocation of the radial head. A radiodense metaphyseal band immediately adjacent to the growth plate was a constant feature in growing patients. Lumbar spine bone mineral density was low and similar to age-matched patients with OI type IV. None of the type V patients presented blue sclerae or dentinogenesis imperfecta, but ligamentous laxity was similar to that in patients with OI type IV. Levels of biochemical markers of bone metabolism generally were within the reference range, but serum alkaline phosphatase and urinary collagen type I N-telopeptide excretion increased markedly during periods of active hyperplastic callus formation. Qualitative histology of iliac biopsy specimens showed that lamellae were arranged in an irregular fashion or had a meshlike appearance. Quantitative histomorphometry revealed decreased amounts of cortical and cancellous bone, like in OI type IV. However, in contrast to OI type IV, parameters that reflect remodeling activation on cancellous bone were mostly normal in OI type V, while parameters reflecting bone formation processes in individual remodeling sites were clearly decreased. Mutation screening of the coding regions and exon/intron boundaries of both collagen type I genes did not reveal any mutations affecting glycine codons or splice sites. In conclusion, OI type V is a new form of autosomal dominant OI, which does not appear to be associated with collagen type I mutations. The genetic defect underlying this disease remains to be elucidated. [source] Role of TNF alpha and PLF in bone remodeling in a rat model of repetitive reaching and grasping,JOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2010Shobha Rani We have previously developed a voluntary rat model of highly repetitive reaching that provides an opportunity to study effects of non-weight bearing muscular loads on bone and mechanisms of naturally occurring inflammation on upper limb tissues in vivo. In this study, we investigated the relationship between inflammatory cytokines and matricellular proteins (Periostin-like-factor, PLF, and connective tissue growth factor, CTGF) using our model. We also examined the relationship between inflammatory cytokines, PLF and bone formation processes. Rats underwent initial training for 5 weeks, and then performed a high repetition high force (HRHF) task (12,reaches/min, 60% maximum grip force, 2,h/day, 3 days/week) for 6 weeks. We then examined the effect of training or task performance with or without treatment with a rat specific TNF, antibody on inflammatory cytokines, osteocalcin (a bone formation marker), PLF, CTGF, and behavioral indicators of pain or discomfort. The HRHF task decreased grip strength and induced forepaw mechanical hypersensitivity in both trained control and 6-week HRHF animals. Two weeks of anti-TNF, treatment improved grip strength in both groups, but did not ameliorate forepaw hypersensitivity. Moreover, anti-TNF, treatment attenuated task-induced increases in inflammatory cytokines (TNF,, IL-1,, and MIP2 in serum; TNF, in forelimb bone and muscles) and serum osteocalcin in 6-week HRHF animals. PLF levels in forelimb bones and flexor digitorum muscles increased significantly in 6-week HRHF animals, increases attenuated by anti-TNF, treatment. CTGF levels were unaffected by task performance or anti-TNF, treatment in 6-week HRHF muscles. In primary osteoblast cultures, TNF,, MIP2 and MIP3a treatment increased PLF levels in a dose dependent manner. Also in primary osteoblast cultures, increased PLF promoted proliferation and differentiation, the latter assessed by measuring Runx2, alkaline phosphatase (ALP) and osteocalcin mRNA levels; ALP activity; as well as calcium deposition and mineralization. Increased PLF also promoted cell adhesion in MC3T3-E1 osteoblast-like cell cultures. Thus, tissue loading in vivo resulted in increased TNF,, which increased PLF, which then induced anabolic bone formation, the latter results confirmed in vitro. J. Cell. Physiol. 225: 152,167, 2010. © 2010 Wiley-Liss, Inc. [source] A Murine Osteosarcoma Cell Line with a Potential to Develop Ossification upon TransplantationCANCER SCIENCE, Issue 6 2001Tomomi Kusumi An Osteosarcoma cell line has been established from a soft tissue tumor that occurred spontaneously in a BALB/c mouse. This cell line showed ossification when transplanted into syngeneic mice. To examine the mechanism of bone formation, the expression of mRNAs for osteoblastic and chon-droblastic markers and factors associated with ossification has been investigated. In culture, the cells exhibited a spindle shape in the growth phase, but had a polygonal shape in the stationary phase. Reverse transcription-polymerase chain reaction analysis showed that the cells expressed mRNAs for pro-,(I) chain of type I collagen, alkaline phosphatase, osteopontin, osteocalcin, and core binding factor al, suggesting differentiation into the stage of osteoblasts during the stationary phase. After transplantation, histological examination revealed small foci of pale blue material and basophilic networks that were scattered in the tumor tissues at one week. The former stained positive with alcian blue, suggesting a chondroid matrix. Pro-,(II) chain of type II collagen mRNA was expressed at one week. A large part of tumors at two and three weeks consisted of basophilic networks, which stained positive via von Kossa's method, indicating a calcified woven bone. In situ hybridization analysis showed strong expression of osteopontin and osteocalcin mRNAs in tumor cells surrounding the bone matrix. Bone morphogenetic protein-6 and -7 mRNAs were detected in transplanted tumors, but not in cultured cells. These results suggest that the cell line has the properties of an osteoblastic lineage when cultured in vitro and has an ossifying ability through endochondral bone formation processes when transplanted in vivo. [source] | ||||||||||