Observed impacts of insulin therapy on callus cell transforming growth factor-beta 1 expression in diabetic rats.

The expression of transforming growth factor-beta 1 (TGF-ß1) inside the callus cells of diabetic rats and the impact of insulin therapy on its expression and biomechanics was investigated. The rats were randomly divided as follows: an insulin therapy group (IT), a diabetic model group (DM), and a non-diabetic control group (NC). Bone specimens from each group were extracted at different times for immunohistochemical observation of the expression of TGF-ß1. Concurrently, the destruction torque and torsional stiffness were detected at different times. One to four weeks after fracture, TGF-ß1 was widely expressed in fractured callus cells and periosteal proliferating cells, while the expression inside diabetic cells was significantly reduced. The expression of TGF-ß1 decreased over the first 68 weeks, and the mature bone cells never expressed TGF-ß1. The destruction torque (Nm) detected in the 6th week revealed that there was a statistically significant difference between the DM, NC, and IT groups (P < 0.01). In conclusion, TGF-ß1 expression was significantly reduced inside the callus cells of diabetic rats. Insulin therapy increased TGF-ß1 expression inside the callus cells of diabetic rats and improved the biomechanical characteristics of the callus.

Periosteal-derived cells for bone bioengineering: a promising candidate.

PURPOSE: Over the last years so many efforts have been made in order to indentify natural sources of osteogenic cells for the success of bone bioengineering. Among them, periosteum tissue has emerged as an interesting candidate. Thus, we decided to evaluate the osteogenic potential of periosteal-derived cells by describing a sequence of biological events since initial morphological changes to mineralization of extracellular matrix (ECM). METHODS: Periosteal-derived cells were obtained from calvarial of adult rats. After the primary culture and expansion, the adherent cells were cultured at 7, 14, 21 and 28 days under a classical osteogenic culture medium in order to evaluate the differentiation of those cells in mature osteoblast. It was monitored by evaluating a time-line of alkaline phosphatase (ALP) activity (biomarker of osteoblast differentiation) and afterwards nodules of mineralization (measured by von Kossa staining and calcium content). RESULTS: Analysis from phase-contrast microscopy revealed mainly morphological changes ranging since fibroblast-shaped (7 days, semi-confluent culture at exponential growth) to polyhedral-shaped cells (14-28 days, confluent culture during differentiation process). ALP activity was linearly increased since 14-28 days while amount of protein remained unchanged. Interesting, our data from von Kossa staining reveled a highest incidence of mineralization nodules at 28 days. CONCLUSION: Taken our results together, we can suggest that periosteal-derived cells present an interesting potential to differentiate in mature osteoblast able to promote mineralization in vitro by incorporating to ECM circulating calcium from extracellular compartment. From our point of view, this source of osteogenic cells can be explored by bioengineers in order to advance therapeutic protocols able to solve bone degenerative lesions.

Gene expression analysis of demineralized bone matrix-induced osteogenesis in human periosteal cells using cDNA array technology.

Demineralized bone matrix (DBM) has been widely investigated as a biomaterial to promote new bone formation and is utilized clinically for bone repair and regeneration. We investigated gene expression patterns of osteogenic differentiation in human periosteal (HPO) cells cultured with demineralized bone matrix, using cDNA array technology. Osteogenic differentiation of HPO cells was determined using alkaline phosphatase assay. In order to examine differential gene expression during osteogenic differentiation, total RNA was isolated from HPO cells in the absence or presence of DBM on day seven and analyzed using osteogenesis cDNA gene array. The selected genes were verified using reverse transcriptase (RT)-PCR analysis. Human periosteal cells differentiated along an osteogenic lineage after treatment of DBM. The alkaline phosphatase activity assay showed that HPO cells differentiated into an osteogenic lineage. Gene expression of HPO cells treated with DBM for seven days was analyzed with cDNA array and RT-PCR analyses. Expression of biglycan, TGF-ß1, and TGF-ßR1 was upregulated, whereas collagen14A1 expression was downregulated, as confirmed by RT-PCR. Human periosteal cells expressed osteogenesis genes when treated with DBM. These findings provide new insight into the capability of demineralized bone matrix to modulate the osteogenic differentiation of human periosteal cells.

Periosteum-derived cells as an alternative to bone marrow cells for bone tissue engineering around dental implants. A histomorphometric study in beagle dogs.

BACKGROUND: The aim of this study is to investigate the potential use of periosteum-derived cells (PCs) for tissue engineering in peri-implant defects. METHODS: Bone marrow cells (BMCs) and PCs were harvested from seven adult beagle dogs, cultured in vitro, and phenotypically characterized with regard to their osteogenic properties. The animals were then subjected to teeth extraction, and 3 months later, two implant sites were drilled, bone dehiscences created, and dental implants placed. Dehiscences were randomly assigned to one of two groups: PCs (PCs + carrier) and BMCs (BMCs + carrier). After 3 months, the animals were sacrificed and the implants with adjacent hard tissues were processed for undecalcified sections. Bone-to-implant contact, bone fill within the limits of implant threads, and new bone area in a zone lateral to the implant were histometrically obtained. RESULTS: In vitro, phenotypic characterization demonstrated that both cell populations presented osteogenic potential, as identified by the mineral nodule formation and the expression of bone markers. Histometrically, an intergroup analysis showed that both cell-treated defects had similar bone fill within the limits of implant threads and bone-to-implant contact (P >0.05), and although a trend toward higher new bone area values was found for the PC group, there was no significant difference between the experimental groups (P >0.05). CONCLUSIONS: Periosteal and bone marrow cells presented a similar potential for bone reconstruction. As such, periosteum may be considered as an alternative source of osteogenic cells in implant dentistry.

Apert p.Ser252Trp mutation in FGFR2 alters osteogenic potential and gene expression of cranial periosteal cells.

Apert syndrome (AS), a severe form of craniosynostosis, is caused by dominant gain-of-function mutations in FGFR2. Because the periosteum contribution to AS cranial pathophysiology is unknown, we tested the osteogenic potential of AS periosteal cells (p.Ser252Trp mutation) and observed that these cells are more committed toward the osteoblast lineage. To delineate the gene expression profile involved in this abnormal behavior, we performed a global gene expression analysis of coronal suture periosteal cells from seven AS patients (p.Ser252Trp), and matched controls. We identified 263 genes with significantly altered expression in AS samples (118 upregulated, 145 downregulated; SNR >or= |0.4|, P

Metabolismo del hueso periodontal: Parte IV. Control local del metabolismo de hueso / Periodontal bone metabolism: Part IV. Local control of bone metabolism

El presente trabajo es el cuarto de una serie de 5 artículos dedicados al estudio del metabolismo del hueso periodontal. En los tres primeros se hizo una descripción de la biología celular del hueso periodontal, de los fenómenos fisiológicos que se encadenan en el ciclo de remodelado óseo y del control sistémico del metabolismo de hueso. El objetivo del presente trabajo es el de presentar una revisión actualizada sobre las diversas sustancias que intervienen en el control local de la fisiología del hueso periodontal. Aunque varían los criterios de clasificación, se puede decir que cuatro familias de sustancias se encargan del control local del metabolismo de hueso: los factores de crecimiento, las monoquinas, las linfoquinas y los derivados del ácido arachidónico (AA). La compleja interacción de estas sustancias entre sí y con respecto a las hormonas osteotrópicas es un fiel reflejo de que la reabsorción y aposición óseas son fenómenos complejos regulados por un estricto control local