Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calcium silicate ceramics have been proposed as new bone repair biomaterials, since they have proved to be bioactive, degradable, and biocompatible. Beta-tricalcium phosphate ceramic is a well-known degradable material for bone repair. This study compared the effects of CaSiO3 (alpha-, and beta-CaSiO3) and beta-Ca3(PO4)2 (beta-TCP) ceramics on the early stages of rat osteoblast-like cell attachment, proliferation, and differentiation. Osteoblast-like cells were cultured directly on CaSiO3 (alpha-, and beta-CaSiO3) and beta-TCP ceramics. Attachment of a greater number of cells was observed on CaSiO3 (alpha-, and beta-CaSiO3) ceramics compared with beta-TCP ceramics after incubation for 6 h. SEM observations showed an intimate contact between cells and the substrates, significant cells adhesion, and that the cells spread and grew on the surfaces of all the materials. In addition, the proliferation rate and alkaline phosphatase (ALP) activity of the cells on the CaSiO3 (alpha-, and beta-CaSiO3) ceramics were improved when compared with the beta-TCP ceramics. In the presence of CaSiO3, elevated levels of calcium and silicon in the culture medium were observed throughout the 7-day culture period. In conclusion, the results of the present study revealed that CaSiO3 ceramics showed greater ability to support cell attachment, proliferation, and differentiation than beta-TCP ceramic.
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PMID:Comparison of osteoblast-like cell responses to calcium silicate and tricalcium phosphate ceramics in vitro. 1676 35

In the present study, the effects of a calcium magnesium silicate bioactive ceramic (akermanite) on proliferation and osteoblastic differentiation of human bone marrow stromal cells (hBMSC) have been investigated and compared with the classical ceramic (beta-tricalcium phosphate, beta-TCP). Akermanite and beta-TCP disks were seeded with hBMSC and kept in growth medium or osteogenic medium for 10 days. Proliferation and osteoblastic differentiation were evaluated on day 1, 4, 7 and 10. The data from the Alamar Blue assay and lactic acid production assay showed that hBMSC proliferated more significantly on akermanite than on beta-TCP. The analysis of osteoblast-related genes, including alkaline phosphatase (ALP), osteopontin (OPN), bone sialoprotein (BSP) and osteocalcin (OC), indicated that akermanite ceramics enhanced the expression of osteoblast-related genes, but type I collagen (COL I) showed no noticeable difference among akermanite and beta-TCP ceramics. Furthermore, this stimulatory effect was observed not only in osteogenic medium, but also in normal growth medium without osteogenic reagents such as l-ascorbic acid, glycerophosphate and dexamethasone. This result suggests that akermanite can promote osteoblastic differentiation of hBMSC in vitro even without osteogenic reagents, and may be used as a bioactive material for bone regeneration and tissue engineering applications.
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PMID:Proliferation and osteoblastic differentiation of human bone marrow-derived stromal cells on akermanite-bioactive ceramics. 1690 40

Platelet-rich plasma (PRP) contains a mixture of growth factors that play an important role in wound and fracture healing. While PRP enhanced bone formation by autogenous cancellous bone grafts, its influence in combination with different bone substitutes remained unknown. This study evaluated the effect of PRP on osteogenic differentiation and ectopic bone formation of human mesenchymal stem cells (MSC) in distinct resorbable calcium phosphate ceramics. Calcium-deficient hydroxyapatite (CDHA) blocks with a large specific surface area (48 m2/g) and beta-tricalcium phosphate (beta-TCP) with a low specific surface area (<0.5 m2/g) were loaded with 2 x 10(5) bone marrow-derived MSC. Half of the specimens were treated with 5-fold concentrated PRP. Biocomposites were implanted subcutaneously into SCID mice or kept under osteogenic culture conditions for 2 weeks before implantation. The addition of PRP increased the specific alkaline phosphatase (ALP) activity (p = 0.012) in undifferentiated MSC/CDHA composites but not in MSC/beta-TCP composites. Osteogenic preinduction was ineffective for CDHA and reduced ALP activity of beta-TCP composites significantly at explantation. Ectopic bone formation was stronger in MSC/CDHA (7/32) compared to MSC/beta-TCP (2/30) composites, but no influence of PRP was evident. In conclusion, the effect of PRP depended on the type of ceramic and the differentiation status of the MSC, and enhanced ALP activity of MSC on the high surface scaffold CDHA only, but PRP did not improve osteogenesis in our setting.
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PMID:Influence of platelet-rich plasma on osteogenic differentiation of mesenchymal stem cells and ectopic bone formation in calcium phosphate ceramics. 1705 23

The effects of medical grade polycaprolactone-tricalcium phosphate (mPCL-TCP) (80:20) scaffolds on primary human alveolar osteoblasts (AOs) were compared with standard tissue-culture plates. Of the seeded AOs, 70% adhered to and proliferated on the scaffold surface and within open and interconnected pores; they formed multi-layered sheets and collagen fibers with uniform distribution within 28 days. Elevation of alkaline phosphatase activity occurred in scaffold-cell constructs independent of osteogenic induction. AO proliferation rate increased and significant decrease in calcium concentration of the medium for both scaffolds and plates under induction conditions were seen. mPCL-TCP scaffolds significantly influenced the AO expression pattern of osterix and osteocalcin (OCN). Osteogenic induction down-regulated OCN at both RNA and protein level on scaffolds (3D) by day 7, and up-regulated OCN in cell-culture plates (2D) by day 14, but OCN levels on scaffolds were higher than on cell-culture plates. Immunocytochemical signals for type I collagen, osteopontin and osteocalcin were detected at the outer parts of scaffold-cell constructs. More mineral nodules were found in induced than in non-induced constructs. Only induced 2D cultures showed nodule formation. mPCL-TCP scaffolds appear to stimulate osteogenesis in vitro by activating a cellular response in AO's to form mineralized tissue. There is a fundamental difference between culturing AOs on 2D and 3D environments that should be considered when studying osteogenesis in vitro.
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PMID:Comparison of human alveolar osteoblasts cultured on polymer-ceramic composite scaffolds and tissue culture plates. 1711 55

Calcium phosphate cements (CPCs) are successfully used as bone substitutes in dentistry and orthopaedic applications. This study investigated the physico-chemical-mechanical properties of and in vitro biological properties (cell response) of CPCs prepared with amorphous calcium carbonate phosphate (ACCP) doped with magnesium (ACCP-Mg), zinc (ACCp-Zn) or fluoride (ACCP-F) ions. The experimental CPC consisted of alpha-TCP, doped ACCP, and MPCM powders as matrix and biphasic calcium phosphate (BCP) granules. X-ray diffraction analysis showed that the matrix converted to apatite with poor crystallinity (reflecting small crystal size) after setting for 24 h, while BCP remained apparently unchanged. Cements with ACCP-F (F-CPC) had shorter setting times and greater compressive strength compared to cements with ACCP-Mg (Mg-CPC) or ACCP-Zn (Zn-CPC). Scanning electron microscopy (SEM) showed that crystals set on Mg-CPC and Zn-CPC were smaller compared to those on F-CPC. The total porosity of Mg-CPC was greater compared to Zn-CPC or F-CPC. Osteoblast-like cells, MC3T3-E1, remained viable and maintained their ability to express alkaline phosphatase in contact with the CPCs with doped ACCPs.
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PMID:Physico-chemical-mechanical and in vitro biological properties of calcium phosphate cements with doped amorphous calcium phosphates. 1712 98

The purpose of this study was to evaluate the therapeutic efficacy of a new calcium phosphate (CaP)-based formulation in improving the bone mineral deficiency in ovariectomized (OVX) rats. The ions release experiments for CaP preparations (G2: 0.46% Mg, 5.78% Zn, and 2.5% F; G3:3.1% Mg, 0.03% Zn, and 3.01% F; G4: 1.25% Mg, 1.77% Zn, 1.35% F) and of a Zn-TCP (G1: 6.17% Zn) powders, the initial Mg and Zn ion release rates of MZF-CaPs were performed in acetate buffer at pH 4.5 (37 degrees C). Wistar rats were divided into six groups including a normal (not OVX) group (GN) and a control, OVX group (GC). Rats in groups GC, G1, G2, G3, G4 were OVX. Suspensions consisting of CaP preparations (G2, G3, G4) and of a Zn-TCP (G1) powders were injected in the right thighs of OVX rats in all groups except for GN and GC, once a week for 4 weeks. GN and GC rats were injected with saline solutions. Plasma was analyzed for Zn land alkaline phosphatase levels. The bone mineral density (BMD) was measured using DEXA and the bone (femur) strength determined using three-point-bending analysis. G1 and G2 groups showed high plasma Zn levels. The area under the curve of plasma Zn was significantly greater in the G1, G2, and GN groups than in the G3, G4, and GC groups (p < 0.05). The BMD and bone mechanical strength of the right femur were significantly higher in the G1, G2, G3, and G4 groups than GC group on day 28. The right femur had significantly greater BMD and bone mechanical strength than the left femur in G1, G2, G3, and G4 groups. However, there was no significant difference in the BMD of the right femur between the G1, G2, G3, and G4 groups. Results indicate that the new injectable CaP formulations are effective in improving bone properties of OVX rats and may be useful in osteoporosis therapy.
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PMID:Efficacy of the injectable calcium phosphate ceramics suspensions containing magnesium, zinc and fluoride on the bone mineral deficiency in ovariectomized rats. 1787 90

Cell-based tissue engineering is thought to be a new therapy for treatment of bone defects and nonunions after trauma and tumor resection. In this study, we explore the in vitro and in vivo osteogenesis of a novel biomimetic construct fabricated by using collagen I gel to suspend rabbit adipose-derived stem cells (rASCs) into a porous poly(lactic-co-glycolic)acid-beta-tricalcium phosphate (PLGA-beta-TCP) scaffold (rASCs-COL/PLGA-beta-TCP). In vitro and in vivo studies of the rASCs-COL/PLGA-beta-TCP composite (group A) were carried out compared with the single combination of rASCs and PLGA-beta-TCP (rASCs/PLGA-beta-TCP; group B), the combination of acellular collagen I gel and PLGA-beta-TCP (COL/PLGA-beta-TCP; group C), and the PLGA-beta-TCP scaffold (group D). Composites of different groups were cultured in vitro for 2 weeks in osteogenic medium and then implanted into the autologous muscular intervals for 8 weeks. After 2 weeks of in vitro culture, alkaline phosphatase activity and extracellular matrix mineralization in group A were significantly higher than in group B (p < 0.01, n = 4). In vivo osteogenesis was evaluated by radiographic and histological analyses. The calcification level was radiographically evident in group A, whereas no apparent calcification was observed in groups B, C and D (n = 4). In group A, woven bone with a trabecular structure was formed, while in group B, only osteoid tissue was observed. Meanwhile, the bone-forming area in group A was significantly higher than in group B (p < 0.01, n = 4). No bone formation was observed in groups C or D (n = 4). In conclusion, by using collagen I gel to suspend rASCs into porous PLGA-beta-TCP scaffold, osteogenic differentiation of rASCs can be improved and homogeneous bone tissue can be successfully formed in vivo.
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PMID:Collagen I gel can facilitate homogenous bone formation of adipose-derived stem cells in PLGA-beta-TCP scaffold. 1793 66

Bone substitute materials with natural bone-like structure are considered to be favorable for bone regeneration. In this work, porous beta-tricalcium phosphate (beta-TCP)/collagen composite consisting of bone-like microstructural units was prepared using nanosized beta-TCP particles and alkaline-disassembled collagen. The resulting composite showed a good interconnecting porous structure with approximately 90% porosity and 100 approximately 300 microm pore size. The pore walls were dense, and the combination status of collagen and nanosized beta-TCP particles demonstrated that nanosized beta-TCP particles tightly connected collagen microfibrils as a bone-like microstructural unit. MTT and alkaline phosphatase (ALP) assays showed that the porous composite had enhanced effects on cellular proliferation and activity of osteoblast compared with a control of pure collagen. It is suggested that the adoption of nanosized beta-TCP particles is a main contribution to the formation of the composite with a bone-like microstructural unit, and the unique microstructure could be a main role for the composite to have the positive influence on osteoblast cell proliferation.
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PMID:Porous beta-tricalcium phosphate/collagen composites prepared in an alkaline condition. 1808 Mar 1

Porous beta-tricalcium phosphate (beta-TCP) scaffolds with controlled architecture and improved mechanical properties were fabricated by combining the gel-casting and rapid prototyping techniques. The pore morphology, size, and distribution of the beta-TCP scaffolds were characterized using a scanning electron microscope. The porosity of the resulting scaffolds with pore size range from 300 to 500 microm was 46%. The average compressive strength was 16.1 MPa. X-ray diffraction was used to determine the crystal structure and chemical composition of scaffolds. The result indicated that the sintering process has not changed the composition of beta-TCP. Flow perfusion culture system was developed in our lab to improve mass transfer for seeded cells. For scaffold/cell constructs cultured under flow perfusion for 4, 8, and 16 days, there was greater scaffold cellularity and alkaline phosphatase activity compared with static culture condition. These results indicated that flow perfusion culture system had evident effects on osteoblast viability and functions in vitro.
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PMID:Osteoblast cell response to beta-tricalcium phosphate scaffolds with controlled architecture in flow perfusion culture system. 1828 35

In this study we investigated not only the cellular proliferation and osteogenic differentiation of human bone marrow stromal cells (hBMSCs) on the novel beta-tricalcium phosphate (beta-TCP) scaffolds in vitro but also bone formation by ectopic implantation in athymic mice in vivo. The interconnected porous beta-TCP scaffolds with pores of 300-500 microm in size were prepared by the polymeric sponge method. beta-TCP scaffolds with the dimension of 3 mm x 3 mm x 3 mm were combined with hBMSCs, and incubated with (+) or without (-) osteogenic medium in vitro. Cell proliferation and osteogenic differentiation on the scaffolds were evaluated by scanning electron microscopy (SEM) observation, MTT assay, alkaline phosphatase (ALP) activity and osteocalcin (OCN) content measurement. SEM observation showed that hBMSCs attached well on the scaffolds and proliferated rapidly. No significant difference in the MTT assay could be detected between the two groups, but the ALP activity and OCN content of scaffolds (+) were much higher than those of the scaffolds (-) (p < 0.05). These results indicated that the novel porous beta-TCP scaffolds can support the proliferation and subsequent osteogenic differentiation of hBMSCs in vitro. After being cultured in vitro for 14 days, the scaffolds (+) and (-) were implanted into subcutaneous sites of athymic mice. In beta-TCP scaffolds (+), woven bone formed after 4 weeks of implantation and osteogenesis progressed with time. Furthermore, tissue-engineered bone could be found at 8 weeks, and remodeled lamellar bone was also observed at 12 weeks. However, no bone formation could be found in beta-TCP scaffolds (-) at each time point checked. The above findings illustrate that the novel porous beta-TCP scaffolds developed in this work have prominent osteoconductive activity and the potential for applications in bone tissue engineering.
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PMID:Tissue-engineered bone formation using human bone marrow stromal cells and novel beta-tricalcium phosphate. 1845 39


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