Alkaline Phosphatase Activity In Cells Research Articles

The in vitro effects of CCN2 on odontoblast-like cells

ObjectiveTo investigate the in vitro effects of CCN2 on odontoblast-like cells proliferation and differentiation. DesignMDPC-23 cells were cultured in DMEM supplemented with 5% FBS. CCN2 was either added to culture media or coated onto culture polystyrene, addition or coating of dH2O was served as control. In the addition group, CCN2 (100 ng/mL) was added into culture media. In the coating group, CCN2 at the concentration of 1000 ng/mL was employed. Cell proliferation was performed using CCK-8 assay. Cell differentiation and mineralization were analyzed by ALPase activity assay, real time RT-PCR and alizarin red staining. One-way ANOVA with post-hoc tukey HSD test was used for statistical analysis. ResultsMDPC-23 cells exhibited robust proliferative activity upon exposure to either soluble or immobilized CCN2. ALP activity of cells cultured on CCN2-modified surface was continuously strengthened from day six (0.831 ± 0.024 units/μg protein versus 0.563 ± 0.006 units/μg protein of control) till day eight (1.035 ± 0.139 units/μg protein versus 0.704 ± 0.061 units/μg protein of control). Gene expression of BSP, OCN and OPN were promoted by soluble CCN2 after 48 h exposure. Moreover, gene expression of BSP, OCN, OPN, ALP, COL1 A1, Runx-2, DSPP and DMP-1 was significantly enhanced by immobilized CCN2. Finally, mineralization of MDPC-23 cells was accelerated by both soluble and immobilized CCN2 to different extent. ConclusionsThe findings indicate that CCN2 promoted proliferation, odontogenic gene expression and mineralization of MDPC-23 cells. It is proposed that CCN2 may be a promising adjunctive formula for dentin regeneration.

MiR-374b promotes osteogenic differentiation of MSCs by degrading PTEN and promoting fracture healing.

To investigate whether miR-374b can promote the differentiation of MSCs into osteoblasts by mediating PTEN, thus promoting fracture healing. Primary cultured mouse mesenchymal stem cells were obtained for following experiments. Flow cytometry was used to determine the expression of MSCs surface antigens to identify the purity. Alizarin red staining was used to detect whether MSCs could differentiate into osteoblasts. QRT-PCR was used to detect the expression of osteogenic marker genes as well as miR-374b and PTEN in bone marrow-derived MSCs from fractured mice model. ALP activity detection kit was used to detect ALP activity in cells. Changes of osteogenic proteins in cells were evaluated by Western blot. Bioinformatics methods were used to predict the binding sites between miR-374 and target genes. Luciferase reporter assay was used to confirm whether miR-374 could bind to the target gene. Under normal culture, MSCs grew into a long fusiform shape on the 4th day. After induced in the osteogenic induction medium for seven days, calcified nodules appeared. The results of the detection of MSCs surface antigen markers showed that CD90 was 99.12%, and CD45 was 0.23%. Alizarin red staining showed that MSCs possess the ability to differentiate into osteogenic. The expression level of MiR-374b and PTEN increased significantly in the early stage of fracture in mice, but no significant difference was observed at a later stage. After overexpression of miR-374b, the cell ALP activity, the expression of osteogenesis-related genes and osteogenesis-related proteins was significantly increased, while after knocking out miR-374b, the opposite result was observed. The result of luciferase reporting assay showed that miR-374b can bind to PTEN. As mentioned above, overexpression of miR-374b resulted in upregulation of osteogenic-related genes and proteins, while over-expression of both PTEN and miR-374b could partly reverse the outcomes. miR-374b can promote osteogenic differentiation of MSCs by degrading PTEN, thereby promoting fracture healing.

Combined treatment with electrical stimulation and insulin-like growth factor-1 promotes bone regeneration in vitro.

Electrical stimulation (ES) and insulin-like growth factor-1 (IGF-1) are widely used in bone regeneration because of their osteogenic activity. However, the combined effects of ES and supplemental IGF-1 on the whole bone formation process remain unclear. In this study, fluorescence staining and an MTT assay were first utilized to observe the influence of ES and IGF-1 on MC3T3-E1 cell proliferation and adhesion in vitro. Subsequently, osteogenic differentiation was evaluated by the alkaline phosphatase activity (ALP) and the expression of osteogenic marker genes. In addition, cell mineralization was determined by alizarin red staining and scanning electron microscopy (SEM). We demonstrated that the MC3T3-E1 cell proliferation was significantly higher for treatments combining IGF-1 and ES than for treatments with IGF-1 alone. The combination of IGF-1 and ES increased the MC3T3-E1 cell ALP activity, the expression of osteogenesis-related genes and the calcium deposition with a clear dose-dependent effect. Our data show the synergistic effect of IGF-1 and ES in promoting the proliferation, differentiation and mineralization of MC3T3-E1 cells, which suggests that it would be more effective to combine the proper dose of IGF-1 with ES to promote local bone damage repair and regeneration.

Simvastatin induces osteogenic differentiation of MSCs via Wnt/β-catenin pathway to promote fracture healing.

This study was designed to investigate whether Simvastatin could facilitate osteogenic differentiation of rat marrow mesenchymal stem cells (MSCs) by modulating the Wnt/β-catenin pathway, thus promoting fracture healing. MSCs were isolated from rat bone marrow specimens and their purity was identified. The third generation of MSCs was cultured in osteoinduction medium containing simvastatin of gradient concentration, and the highest dose of simvastatin that did not cause cell proliferation was determined by the result of the CCK8 assay. The effects of simvastatin on osteogenic differentiation of MSCs were evaluated by ALP activity, Alizarin red staining, alkaline phosphatase staining and osteoblast-specific gene expression. Finally, Wnt pathway antagonist DKK1 and β-catenin disturbing agent were added to MSCs to detect the ALP activity, Alizarin red staining, alkaline phosphatase staining and osteoblast-specific genes of MSCs respectively, and to evaluate whether simvastatin promoted osteogenic differentiation of MSCs by activating Wnt/β-catenin pathway. After osteoinduction, simvastatin of 0.3 nmol/L was found to be the highest dose that did not induce the proliferation of MSCs. After treated with 0.3 nmol/L simvastatin for 7 days, the ALP activity of cells and the number of cell calcified nodules significantly increased. Meanwhile, the expression of osteoblast-related genes, including ALP, Runx2, OCN, and OPN, were clearly up-regulated. However, when the MSCs were treated with DKK1 for 7 days, the ALP activity and the expression of osteoblast-related genes, including ALP, Runx2, OCN, and OPN, were found decreased. Simvastatin markedly up-regulated the expression of the β-catenin protein, while transfection of β-catenin shRNA inhibited the expression of osteoblast-related genes including ALP, Runx2, OCN, and OPN. Simvastatin can promote the differentiation of rat MSCs into osteoblast-like cells, and its mechanism may be related to the Wnt/β-catenin pathway.

A unique off-on near-infrared cyanine-based probe for imaging of endogenous alkaline phosphatase activity in cells and in vivo

Alkaline phosphatase (ALP) is a class of enzymes that are widely found in various tissues of the human body. It plays important roles in regulating diverse cellular functions. The aberrant levels of serum ALP are implicated in diseases. The development of sensitive and accurate detection tool for evaluating the level changes of ALP in living organisms will be very helpful in the fields of biochemistry, cytology and clinical medicine. Herein, we develop a near-infrared probe (QcyP) for the specific detection of different ALP levels both in different cell lines and in tumor-bearing mice models. The probe is composed of two moieties: a unique heptamethine cyanine fluorophore and a phosphate monoester. ALP can trigger an off-on fluorescence switch via an enzyme-catalyzed cleavage of the phosphate group. The fluorescence regulation mechanism is based on the rearrangement of the conjugated π-electron system. The probe exhibits high selectivity and good sensitivity towards ALP. The results demonstrate that the probe QcyP not only can be applied to discriminate the levels of ALP in different cell lines, but also can distinguish the ALP level changes between hepatic tumor mice model and normal mice.

Unusual Versatility of the Filamentous, Diazotrophic Cyanobacterium Anabaena torulosa Revealed for Its Survival during Prolonged Uranium Exposure.

Reports on interactions between cyanobacteria and uranyl carbonate are rare. Here, we present an interesting succession of the metabolic responses employed by a marine, filamentous, diazotrophic cyanobacterium, Anabaena torulosa for its survival following prolonged exposure to uranyl carbonate extending up to 384 h at pH 7.8 under phosphate-limited conditions. The cells sequestered uranium (U) within polyphosphates on initial exposure to 100 μM uranyl carbonate for 24 to 28 h. Further incubation until 120 h resulted in (i) significant degradation of cellular polyphosphates causing extensive chlorosis and cell lysis, (ii) akinete differentiation followed by (iii) extracellular uranyl precipitation. X-ray diffraction (XRD) analysis, fluorescence spectroscopy, X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) spectroscopy established the identity of the bioprecipitated uranium as a U(VI) autunite-type mineral, which settled at the bottom of the vessel. Surprisingly, A. torulosa cells resurfaced as small green flakes typical of actively growing colonies on top of the test solutions within 192 to 240 h of U exposure. A consolidated investigation using kinetics, microscopy, and physiological and biochemical analyses suggested a role of inducible alkaline phosphatase activity of cell aggregates/akinetes in facilitating the germination of akinetes leading to substantial regeneration of A. torulosa by 384 h of uranyl incubation. The biomineralized uranium appeared to be stable following cell regeneration. Altogether, our results reveal novel insights into the survival mechanism adopted by A. torulosa to resist sustained uranium toxicity under phosphate-limited oxic conditions.IMPORTANCE Long-term effects of uranyl exposure in cyanobacteria under oxic phosphate-limited conditions have been inadequately explored. We conducted a comprehensive examination of the metabolic responses displayed by a marine cyanobacterium, Anabaena torulosa, to cope with prolonged exposure to uranyl carbonate at pH 7.8 under phosphate limitation. Our results highlight distinct adaptive mechanisms harbored by this cyanobacterium that enabled its natural regeneration following extensive cell lysis and uranium biomineralization under sustained uranium exposure. Such complex interactions between environmental microbes such as Anabaena torulosa and uranium over a broader time range advance our understanding on the impact of microbial processes on uranium biogeochemistry.

Reaction-Based Off-On Near-infrared Fluorescent Probe for Imaging Alkaline Phosphatase Activity in Living Cells and Mice.

Alkaline phosphatases are a group of enzymes that play important roles in regulating diverse cellular functions and disease pathogenesis. Hence, developing fluorescent probes for in vivo detection of alkaline phosphatase activity is highly desirable for studying the dynamic phosphorylation in living organisms. Here, we developed the very first reaction-based near-infrared (NIR) probe (DHXP) for sensitive detection of alkaline phosphatase activity both in vitro and in vivo. Our studies demonstrated that the probe displayed an up to 66-fold fluorescence increment upon incubation with alkaline phosphatases, and the detection limit of our probe was determined to be 0.07 U/L, which is lower than that of most of alkaline phosphatase probes reported in literature. Furthermore, we demonstrated that the probe can be applied to detecting alkaline phosphatase activity in cells and mice. In addition, our probe possesses excellent biocompatibility and rapid cell-internalization ability. In light of these prominent properties, we envision that DHXP will add useful tools for investigating alkaline phosphatase activity in biomedical research.

Initial osteoblast functions on a type of near β-type titanium alloys surfaces modified by the double glow plasma nitriding technology

Objective: To evaluate the adhesion, proliferation, alkaline phosphatase (ALP) activity and the expression of osteogenesis-related genes and osteoprotegerin (OPG)/receptor activator of NF-κB ligand (RANKL) of osteoblast-like cells on a type of near β-type titanium alloys (Ti-5Zr-3Sn-5Mo-15Nb, TLM) surfaces modified by the double glow plasma nitriding technology, and to investigate the effect of the modified surfaces on the initial functions of osteoblast-like cells. Methods: The surfaces of TLM were modified by the double glow plasma nitriding technology. TLM surfaces without modification were used as control. Cell morphology was observed with scanning electron microscopy (SEM). Methyl thiazolyl tetrazolium (MTT) method was used to measure cell proliferation. Cell ALP activity was evaluated by using reagent kits. The mRNA expression of Runt-related transcription factor-2 (RUNX2), typeⅠcollagen alpha 1 chain (COLⅠ α1) and OPG/RANKL were examined by quantitative real-time PCR(qRT-PCR). Results: Four hour following cell alture, cells on modified surfaces extend filopodia and intercellular junction was tight. Three days later, cell proliferation (0.277±0.007) was significantly higher than that in control group (0.249±0.004) (P<0.01). After two weeks, ALP activity on TLM modified layer (173.6±1.89) was significantly higher than that on unmodified TLM (162.6±2.4) (P<0.01). The mRNA expression of osteoblast marker RUNX2, COLⅠα1 were stronger than that in control group (P<0.05). The expression of OPG mRNA was higher than that in control group (P<0.01), and RANKL mRNA expression was significantly lower than that in control group (P<0.05). Conclusions: The TLM surface modified by the double glow plasma nitriding technology has a positive effect on osteoblasts initial adhesion, proliferation and differentiation, and it can also improve expression of OPG mRNA and has an inhibitory effect on RANKL mRNA expression of osteoblasts.

再生骨用担体材料としての灰化ウシ骨の骨伝導性に関する研究

Calcined bone is attractive as scaffold material for tissue-engineered bones in biocompatibility and low manufacturing cost. However, its osteoconductivity is still unknown. The objective of this study is to investigate the effects of calcination temperature on the osteoconductive of calcined bone. Bovine compact bones (BCB) were calcined at 600°C or 900°C for 22 hours and immersed in the culture medium at 37°C. MC3T3-E1 osteoblastic cells were cultured on the samples. The osteoconconductivity of calcined bone was evaluated by investigating calcium absorbability in culture medium and alkaline phosphatase (ALP) activity of the cells. Either calcined bone at 600°C or 900°C decreased calcium concentrations in the medium. On the other hand, ALP activity of cells cultured on BCB increased, but it decreased on the 600°C and 900°C samples after 7days. However, the ALP activity was improved by immersing the samples in the medium for 3 days before cell seeding. The result suggests that presence of organic components is important for the osteoconductivity of calcined bone.

Immobilization of calcium and phosphate ions improves the osteoconductivity of titanium implants

In this work, to elevate weak osteoconductivity of titanium (Ti) implant, we prepared a Ti implant having both calcium and phosphate ions on its surface. To modify calcium and phosphate ions onto Ti, phosphate ions were first immobilized by treating the Ti with a NaH2PO4 solution, followed by CaCl2 treatment to immobilize calcium ions, which created the calcium and phosphate ions-modified Ti (Ca-P-Ti). X-ray photoelectron spectroscopy and thin-layer X-ray diffraction measurement confirmed that both phosphate and calcium ions were co-immobilized onto the Ti surface on the molecular level. Three-hour after seeding MC3T3-E1 murine pre-osteoblast cells on substrates, cell number on Ca-P-Ti was much larger than that of Ti and phosphate-modified Ti (P-Ti), but was similar to that of calcium-modified Ti (Ca-Ti). Also, MC3T3-E1 cells on Ca-P-Ti expressed larger amount of vinculin, a focal adhesion protein, than those on other substrates, probably resulting in larger cell size as well as greater cell proliferation on Ca-P-Ti than those on other substrates. Alkaline phosphatase activity of cells on Ca-P-Ti was greater than those on Ti and P-Ti, but was almost comparable to that of Ca-Ti. Moreover, the largest amount of bone-like nodule formation was observed on Ca-P-Ti. These results provide evidence that calcium and phosphate ions-co-immobilization onto Ti increased the osteoconductivity of Ti by stimulating the responses of pre-osteoblast cells. This simple modification would be promising technique for bone tissue implant including dental and orthopedic implants.

Effects of radiation doses from different dental imaging modalities on cell-implant interaction: A comparison with cell culture study

Objectives: The effect of radiation after exposing with dental imaging devices on cell-implant material interaction has not been adequately studied. The aim of this study is to determine the effects of radiation by measuring proliferation and differentiation of the human fetal osteoblast (hFOB) cells using dental imaging techniques and evaluate the result in vitro conditions at cellular stage. Materials and Methods: hFOB were irradiated 1 day after planting on commercially pure titanium discs. Radiation was single dose in one exposure using five different dental imaging techniques as conventional dental and digital dental X-ray tubes, conventional panoramic, digital panoramic and cone beam computerized tomography (CBCT). In the 8 th day of experiment, exposured cells and nonexposured control group cells which planted on discs were compared and examined regarding their proliferations and alkaline phosphatase (ALP) activities. Results were evaluated using Student's Independent t-test in SPSS 15.0 (SPSS Inc., Chicago, IL, USA). Results: In exposure with digital dental imaging device, ALP activities of cells are increased according to the control group and statistically, with 0, 2 s of exposure, a significant increment was found (P < 0.05). The exposures with CBCT and conventional dental imaging devices decreased cell proliferation compared with the control groups, but it was found statistically insignificant. In exposure with the other dental imaging devices, cell proliferation increased insignificantly. Conclusions: Our in vitro study suggests that the ionizing radiation produced by digital dental imaging devices may result to certain increment of the cell number and activities. More controlled study should be made with cell cultures in order to verify the exact activity of digital dental imaging.

Characteristics and in vitro response of thin hydroxyapatite-titania films produced by plasma electrolytic oxidation of Ti alloys in electrolytes with particle additions.

The enhancement of the biological properties of Ti by surface doping with hydroxyapatite (HA) is of great significance, especially for orthodontic applications. This study addressed the effects of HA particle size in the electrolyte suspension on the characteristics and biological properties of thin titania-based coatings produced on Ti-6Al-4V alloy by plasma electrolytic oxidation (PEO). Detailed morphological investigation of the coatings formed by a single-stage PEO process with two-step control of the electrical parameters was performed using the Minkowski functionals approach. The surface chemistry was studied by glow discharge optical emission spectroscopy and Fourier transform infrared spectroscopy, whereas mechanical properties were evaluated using scratch tests. The biological assessment included in vitro evaluation of the coating bioactivity in simulated body fluid (SBF) as well as studies of spreading, proliferation and osteoblastic differentiation of MC3T3-E1 cells. The results demonstrated that both HA micro- and nanoparticles were successfully incorporated in the coatings but had different effects on their surface morphology and elemental distributions. The micro-particles formed an irregular surface morphology featuring interpenetrated networks of fine pores and coating material, whereas the nanoparticles penetrated deeper into the coating matrix which retained major morphological features of the porous TiO2 coating. All coatings suffered cohesive failure in scratch tests, but no adhesive failure was observed; moreover doping with HA increased the coating scratch resistance. In vitro tests in SBF revealed enhanced bioactivity of both HA-doped PEO coatings; furthermore, the cell proliferation/morphometric tests showed their good biocompatibility. Fluorescence microscopy revealed a well-organised actin cytoskeleton and focal adhesions in MC3T3-E1 cells cultivated on these substrates. The cell alkaline phosphatase activity in the presence of ascorbic acid and β-glycerophosphate was significantly increased, especially in HA nanoparticle-doped coatings.

Translationally controlled tumor protein supplemented chitosan modified glass ionomer cement promotes osteoblast proliferation and function.

The objective of this study was to evaluate the effect of translationally controlled tumor protein (TCTP) supplemented in a novel glass ionomer cement (BIO-GIC) on normal human osteoblasts (NHost cells). BIO-GIC was a glass ionomer cement (GIC) modified by adding chitosan and albumin to promote the release of TCTP. NHost cells were seeded on specimens of GIC, GIC+TCTP, BIO-GIC and BIO-GIC+TCTP. Cell proliferation was determined by BrdU assay. It was found that BIO-GIC+TCTP had significantly higher proliferation of cells than other specimens. Bone morphogenetic protein-2 (BMP-2) and osteopontin (OPN) gene expressions assessed by quantitative real time PCR and alkaline phosphatase (ALP) activity were used to determine cell differentiation. Bone cell function was investigated by calcium deposition using alizarin assay. Both BMP-2 and OPN gene expressions of cells cultured on specimens with added TCTP increased gradually up-regulation after day 1 and reached the highest on day 3 then down-regulation on day 7. The ALP activity of cells cultured on BIO-GIC+TCTP for 7 days and calcium content after 14 days were significantly higher than other groups. BIO-GIC+TCTP can promote osteoblast cells proliferation, differentiation and function.

Synthesis and characterization of nanosized calcium phosphates by flame spray pyrolysis, and their effect on osteogenic differentiation of stem cells

The present study evaluates the synthesis of biocompatible osteoconductive and osteoinductive nano calcium phosphate (CaP) particles by industrially applied, aerosol-derived flame spray pyrolysis method for biomedical field. Calcium phosphate nanoparticles were produced in a range of calcium-to-phosphorus ratio, (1.20–2.19) in order to analyze the morphology and crystallinity changes, and to test the bioactivity of particles. The characterization results confirmed that nanometer-sized, spherical calcium phosphate particles were produced. The average primary particle size was determined as 23 nm by counting more than 500 particles in TEM pictures. XRD patterns, HRTEM, SAED, and SEM analyses revealed the amorphous nature of the as-prepared nano calcium phosphate particles at low Ca/P ratios. Increases in the specific surface area and crystallinity were observed with the increasing Ca/P ratio. TGA–DTA analysis showed that the thermally stable crystal phases formed after 700 °C. Cell culture studies were conducted with urine-derived stem cells that possess the characteristics of mesenchymal stem cells. Synthesized amorphous nanoparticles did not have cytotoxic effect at 5–50 μg/ml concentration range. Cells treated with the as-prepared nanoparticles had higher alkaline phosphatase (ALP) enzyme activity than control cells, indicating osteogenic differentiation of cells. A slight decrease in ALP activity of cells treated with two highest Ca:P ratios at 50 μg/ml concentration was observed at day 7. The findings suggest that calcium phosphate nanoparticles produced in this work have a potential to be used as biomaterials in biomedical applications.

Tauroursodeoxycholic acid attenuates inorganic phosphate-induced osteoblastic differentiation and mineralization in NIH3T3 fibroblasts by inhibiting the ER stress response PERK-eIF2α-ATF4 pathway.

Ectopic ossification occurs in a wide range of common and genetic diseases, but its molecular mechanisms and effective therapeutic targets remain to be clarified. The aim of the study is to investigate whether endoplasmic reticulum (ER) stress is involved in ectopic ossification and ER stress inhibitor tauroursodeoxycholic acid (TUDCA) has potential to treat the pathological conditions. In this study, inorganic phosphate (Pi)-induced NIH3T3 fibroblasts induced osteogenesis and mineralization was used as an in vitro model for ectopic ossification. Various concentrations of TUDCA (0.1, 1, 5, 10 μM) were added during osteogenic induction. Osteoblast differentiation and minerlization were determined by RT-qPCR, alkaline phosphatase (ALP) activity assay, Alizarin Red-S (AR-S) staining, and calcium deposition. ER stress signalling components were detected by Western-blot analysis. We found ER stress was activated by inorganic phosphate in NIH3T3 cells. During osteogenic induction, TUDCA inhibited NIH3T3 cells ALP activity and mineral nodule formation. In addition, TUDCA caused decreased expression of osteoblastic markers Runx2, Col1a1, ALP, OCN. Mechanistically, TUDCA inhibited the ER stress response PERK-eIF2α-ATF4 pathway during osteogenesis. In conclusion, TUDCA could inhibit fibroblasts mineralization via supressing the ER stress response PERK-eIF2α-ATF4 pathway, and has potential pharmacologic and therapeutic applications for treating ectopic ossification associated diseases.

1α,25-dihydroxyvitamin D3 promotes osteogenic activity and downregulates proinflammatory cytokine expression in human periodontal ligament cells.

The aim of this study was to assess the impact of 1α,25-dihydroxyvitamin D3 (vitamin D3) on osteogenic and inflammatory properties of human periodontal ligament (PDL) cells and investigate underlying mechanisms. Human PDL cells, obtained from four subjects, were stimulated with vitamin D3 for 4-48h. The bone markers osteopontin and osteocalcin and proinflammatory cytokine/chemokine expression was determined by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Cytokine and chemokine expression was determined after stimulation with the inflammation promoter lipopolysaccharide (LPS) in the presence or absence of vitamin D3. Alkaline phosphatase activity was assessed using p-nitrophenylphosphate substrate. Treatment with 30ng/mL of vitamin D3, corresponding to an optimal plasma concentration of vitamin D, for 24h had no effect on PDL cell number and morphology but increased PDL cell osteopontin and osteocalcin mRNA expression by about 70 and 40%, respectively, and, moreover, treatment with vitamin D3 for 48h enhanced PDL cell alkaline phosphatase activity by about two times showing that vitamin D3 exerts pro-osteogenic effects in human PDL cells. Stimulation with LPS (1μg/mL) for 4h increased PDL cell interleukin (IL)-6 cytokine and chemokine ligand 1 (CXCL1) chemokine mRNA expression several fold. The LPS-induced increase in IL-6 and CXCL1 transcripts was attenuated by vitamin D3 (30ng/mL). Treatment with vitamin D3 (3-300ng/mL) for 24h reduced the LPS-evoked increase in PDL cell IL-6 protein by about 50%. Vitamin D3 (30ng/mL) had no effect on LPS-induced IL-1β and MCP-1 mRNA expression. Vitamin D3 promotes osteogenic differentiation but also downregulates inflammation promoter-induced IL-6 cytokine and CXCL1 chemokine expression in human PDL cells, suggesting that vitamin D3 both stimulates bone regeneration and antagonizes inflammation in human periodontal tissue.

Comparison of Biocompatibility of Various Membranes with Fibroblastsy

Objective: Different techniques have been suggested for the repair of bone defects at the injured sites. Use of biomembranes, or application of plasma rich in growth factor (PRGF) at the site of proliferation of osteoblasts are among the suggested techniques. The current study aimed to compare the biocompatibility of human periodontal ligament fibroblasts (hPLF) cultured on Hypro-Sorb F, Pericardium and Tutodent resorbable membranes coated with PRGF.Methods: This experimental study was conducted on four resorbable membranes namely Hypro- Sorb F, Pericardium, Tutodent and Vicryl. Fibroblast cells isolated from the periodontal ligament of premolar tooth were passaged three times and 105 cells/ cm2 were cultured on membranes coated with PRGF. After 72 hours, the cells were evaluated in terms of biocompatibility and alkaline phosphatase (ALP) activity. Statistical analysis was carried out using one-way ANOVA.Results: PRGF increased cell adhesion and Tutodent membrane coated with PRGF showed the highest cell adhesion compared with Hypro-Sorb F and Pericardium membranes (p=0.005).Conclusion: PRGF increases cell viability and ALP activity of cells on biomembranes. PRGF treatment increases the adhesion of fibroblast cells to these membranes.

Co-doping of hydroxyapatite with zinc and fluoride improves mechanical and biological properties of hydroxyapatite

Hydroxyapatite (HA) co-doped with Zn2+ and F− ions was synthesized by precipitation method for the first time in this study. FTIR spectroscopy revealed Zn2+ and F− ions incorporation into HA structure. Co-doping of Zn2+ and F− ions decreased unit cell volume of HA and decreased grain sizes. Zn2+ or 5mol% F− addition into HA significantly improved its density. Microhardness was increased with Zn2+ addition and further increase was detected with F− co-doping. Zn2+ and F− co-doped samples had higher fracture toughness than pure HA. Zn2+ incorporation to the structure resulted in an increase in cell proliferation and ALP activity of cells, and further increase was observed with 1mol% F− addition. With superior mechanical properties and biological response 2Zn1F is a good candidate for biomedical applications.

Ti-SrO metal matrix composites for bone implant materials.

Titanium-strontia (Ti-SrO) metal matrix composites (MMCs) with 0, 1, 3 and 5% (weight ratio) of SrO have been fabricated through the powder metallurgy method. Increasing the weight ratio of SrO from 0 to 5%, the compressive strength of Ti-SrO MMCs increased from 982 MPa to 1753 MPa, while the ultimate strain decreased from 0.28 to 0.05. The elastic moduli of Ti-3SrO and Ti-5SrO MMCs were higher than those of Ti and Ti-1SrO MMC samples. Additionally, the micro hardness of Ti-SrO MMCs was enhanced from 59% to 190% with the addition of SrO. The enhanced compression strength and micro hardness of Ti-SrO MMCs were attributed to the Hall-Petch effect and the SrO dispersion strengthening in the Ti matrix. MTS assay results demonstrated that Ti-SrO MMCs with 3% SrO exhibited enhanced proliferation of osteoblast-like cells. Alkaline phosphatase activity of cells was not influenced significantly on the surface of Ti-SrO MMCs compared with pure Ti in a term longer than 10 days. The cell morphology on the Ti-SrO MMCs was observed using confocal microscopy and scanning electron microscopy, which confirmed that the Ti-3%SrO MMCs showed optimal in vitro biocompatibility.

A new implant with solid core and porous surface: The biocompatability with bone

This research investigated osteogenic potencies of Farthing-Fray-Chen Titanium (FFcTi) implant with transitional porous-solid structure. The material characteristics, biomechanical property, osteogenic performances were assessed. FFcTi showed similar roughness as sand-blasted and acid etched titanium (SA), but was more hydrophilic than SA and machined commercial pure titanium (MA). Young's modulus of FFcTi implant in compressive tests was 15.8 ± 6.3 GPa, which was close to bone. In vitro observations manifested excellent spreading abilities of MC3T3-E1 cell on FFcTi and SA. Adhesion rates of MC3T3-E1 cells at 4 h gradually decreased on MA, SA, and FFcTi surfaces (MA > SA, p < 0.01; SA > FFcTi, p < 0.05), while cell proliferation ability on FFcTi was weaker than MA during 1-6 days (p < 0.01) and similar to MA and SA in day 11. ALP activity of cells on FFcTi at 14 day was higher than MA and lower than SA (p < 0.01). In a bone defect model of rabbits, BIC and bone volum ratio within 50 μm were significantly higher for FFcTi than MA (BIC, p < 0.01; BT0.05, p < 0.05) while bone volume ratio within 100 and 500 μm were of no differences. Micro CT analysis also showed similar results to the histomorphometric data. Thus, we conclude that FFcTi with melting sphere based multiporous structure has a hydrophilic, rough surface, and close modulus to bone. In vitro, its low proliferation and ALP activity promotion were similar to other micro scale roughed surface. In vivo test showed better osteogenesis ability when compared with MA at least in 2 weeks. Thus, this Farthing-Fray-Chen Titanium implant seems to hold considerable potential for bone implant applications.