SDF-1 modulates periodontal ligament-Mesenchymal Stem Cells (pdl-MSCs).

BACKGROUND/OBJECTIVES: In this in vitro study, the effects of Stromal cell-derived factor-1 (SDF-1) was evaluated on the periodontal ligament-Mesenchymal Stem Cells (pdl-MSCs) functions. MATERIAL AND METHODS: Real-time cell analyzer-single plate (RTCA-SP) was employed for proliferation, and RTCA-dual purpose (DP) was utilized for pdl-MSCs migration potential treated with different SDF-1 concentrations (0, 0.1, 1, 10, 100, 200, and 400 ng/ml). Based on the dose-response findings, 10 ng/ml SDF-1 was used for further mRNA experiments. RNAs isolated at 6 and 24 h were checked using quantitative RT-PCR for mineralized tissue-associated genes including type I collagen (COL I), osteocalcin (OCN), osteopontin (OPN), and runt-related transcription factor 2 (Runx2). cRNA was synthesized for 6 h, and whole-genome array analysis was performed for over 47.000 probes. Data were subjected to quantile normalization before analysis. RESULTS: Increased proliferation and migration were observed in pdl-MSCs treated with 0.1, 1, and 10 ng/ml SDF-1. Increased COL I was observed at both time points: 6 and 24 h. While there was no significant change for OCN, OPN, and Runx2 at 6 h, SDF-1 up-regulated OCN and OPN, but down-regulated Runx2 mRNA expressions at 24 h. IL-8 and ESM1 genes were differentially expressed over twofold when the pdl-MSCs were exposed to SDF-1 at whole-genome array analysis. IL-8 induction was confirmed with RT-PCR. CONCLUSION: Findings of this study displayed that SDF-1 modulated pdl-MSCs which were important for periodontal regeneration, inducing migration and proliferation, and regulating extracellular matrix synthesis in favor of the formation of new attachment.

Comparison of Different Sources of Mesenchymal Stem Cells: Palatal versus Lipoaspirated Adipose Tissue.

OBJECTIVES: The purpose of this study was to compare the proliferation and differentiation potential of mesenchymal stem cells (MSCs) derived from palatal adipose tissue (PAT) and lipoaspirated adipose tissue (LAT). MATERIALS AND METHODS: PATs were obtained from 2 healthy female patients undergoing surgery for gingival recession, and LATs were obtained from 2 healthy female patients undergoing plastic surgery. LAT- and PAT-derived MSCs were confirmed by flow cytometry using MSC-specific surface markers. The multilineage differentiation capacity of the MSCs was analyzed. The expression of immunophenotyping, embryonic, and differentiation markers was compared between both MSC lines. The proliferation of PAT- and LAT-MSCs was evaluated using a real-time cell analyzer, and telomerase activity was determined using an ELISA-based TRAP assay. Stem cells isolated from PAT and LAT were analyzed by real-time PCR and whole genome array analysis. RESULTS: The cells isolated from PAT had MSC characteristics. In addition, PAT-MSCs had significantly higher alkaline phosphatase activity and osteogenic potential than LAT-MSCs. Although the proliferation and telomerase activities of LAT-MSCs were higher than those of PAT-MSCs, the difference was not statistically significant. The level of embryonic stem cell markers (Oct4 and Nanog) was higher in LAT-MSCs than in PAT-MSCs. The whole genome array analysis demonstrated that 255 gene sequences were differentially expressed, with more than a twofold change in expression. CONCLUSIONS: This is the first comparative analysis of the isolation and characterization of MSCs from PAT and LAT. PAT is an accessible source of MSCs, which could be used in periodontal and craniofacial tissue engineering.

Biostimulation with diode laser positively regulates cementoblast functions, in vitro.

The aim of this study was to evaluate the effects of diode laser biostimulation on cementoblasts (OCCM.30). A total of 40 root plates were obtained from healthy third molar teeth and assigned to the following two groups: (1) control group and (2) laser-treated group. Root plates were placed into the cell culture inserts, and OCCM.30 cells were seeded onto root plates. Cells were irradiated with a low level of diode laser (power: 0.3 W in continuous wave, 60 s/cm2). Proliferation and mineralized tissue-associated gene's and BMP's messenger RNA (mRNA) expressions of cementoblasts were evaluated. Total RNAs were isolated on day 3 and integrin-binding sialoprotein (Ibsp), bone gamma-carboxyglutamate protein (Bglap), Type I collagen (Col1a1), osteoblastic transcription factor, runt-related transcription factor (Runx2), and Bone Morphogenetic Protein (BMP)-2, 3, 4, 6, and 7 mRNA expressions were determined using quantitative RT-PCR. von Kossa staining was performed to evaluate biomineralization of OCCM.30 cells. In the proliferation experiment, while there was no significant difference until 96 h, laser irradiation retarded the decrease in cell proliferation trend after 96 h compared to the untreated control group. Statistically significant increase in Ibsp, Bglap, and BMP-2,3,6,7 mRNA expressions were noted in the laser groups when compared to the untreated control group (p < 0.05). Laser irradiation induced mineralized nodule formation of cementoblasts. The results of this study reveal that the biostimulation setting of diode laser modulates the behavior of cementoblasts inducing mineralized tissue-associated gene's mRNA expressions and mineralization. Therefore, biostimulation can be used during regenerative periodontal therapies to trigger cells with periodontal attachment apparatus.

Extremely high boron tolerance in Puccinellia distans (Jacq.) Parl. related to root boron exclusion and a well-regulated antioxidant system.

Recent studies indicate an extremely high level of tolerance to boron (B) toxicity in Puccinellia distans (Jacq.) Parl. but the mechanistic basis is not known. Puccinellia distans was exposed to B concentrations of up to 1000 mg B L-1 and root B uptake, growth parameters, B and N contents, H2O2 accumulation and ·OH-scavenging activity were measured. Antioxidant enzyme activities including superoxide dismutase (SOD), ascorbate peroxidase, catalase, peroxidase and glutathione reductase, and lipid peroxidation products were determined. B appears to be actively excluded from roots. Excess B supply caused structural deformations in roots and leaves, H2O2 accumulation and simultaneous up-regulation of the antioxidative system, which prevented lipid peroxidation even at the highest B concentrations. Thus, P. distans has an efficient root B-exclusion capability and, in addition, B tolerance in shoots is achieved by a well-regulated antioxidant defense system.

Periodontal ligament cell behavior on different titanium surfaces.

AIM: The purpose of this study was to investigate proliferation, morphology, mineralization and mRNA expressions of mineralized tissue associated proteins of PDL cells on smooth (S), sandblasted small-grit (SSG), sandblasted large-grit (SLG) and sodium titanate (NaTi) coated titanium alloys, in vitro. METHODS AND MATERIALS: PDL cells were cultured with DMEM media containing 10% FBS on the S, SSG, SLG and NaTi titanium surfaces. PDL cell proliferation, mineralization and immunohistochemistry experiments for Bone Sialoprotein (BSP) were performed. The morphology of the PDL cells was examined using confocal and scanning electron microscopy (SEM). Gene expression profiles of cells were evaluated using a quantitative-polymerase chain reaction (Q-PCR) for type I collagen (COL I), Osteocalcin (OCN), osteopontin (OPN) and Runt-related transcription factor-2 (Runx2) on days 7 and 14. RESULTS: Proliferation results on days 6 and 10 were similar in groups, while those of day 13 revealed a decrease in the NaTi group when compared to the S group. NaTi surface induced BSP mRNA expression which was correlated with mineralization tests and BSP immunostaining results. Increased Runx2 mRNA expression was also noted in the NaTi surface when compared to other surfaces. CONCLUSIONS: This study considers the NaTi surface as a potential alternative to SSG and SLG surfaces. This surface might provide a promising environment for PDL ligament-anchored implants.

Boron as Boric Acid Induces mRNA Expression of the Differentiation Factor Tuftelin in Pre-Osteoblastic MC3T3-E1 Cells.

The effects of boron on the formation and maintenance of mineralized structures at the molecular level are still not clearly defined. Thus, a study was conducted using MC3T3-E1 cells to determine whether boron affected mRNA expressions of genes associated with bone/alveolar bone formation around the teethMC3T3-E1 (clone 4) cells were cultured in media treated with boric acid at concentrations of 0, 0.1, 10, 100, or 1000 ng/ml. Total RNAs of each group were isolated on day 3. Gene expression profiles were determined by using RT2 Profiler PCR micro-array that included 84 genes associated with osteogenic differentiation. Tuftelin1 mRNA expression was upregulated by all boron treatments. The upregulation was confirmed by quantitative RT-PCR using the tuftelin probe. While 100 ng/ml had no effect on the integrin-α2 (Itga2) transcript and 1 ng/ml boric acid induced Itga2 mRNA expression (2.1-fold), 0.1, 10, and 1000 ng/ml boric acid downregulated the integrin-α2 gene transcript 2.2-, 1.5-, and 2.1-fold respectively. While 0.1 ng/ml boric acid induced BMP6, increased BMP1r mRNA expression (1.5 fold) was observed in 1000 ng/ml boric acid treatment. The findings suggest that boron affects the regulation of the tuftelin1 gene in osteoblastic cells. Further studies are needed to establish that the beneficial actions of boron on alveolar bone and tooth formation and maintenance include an effect on the expression of the tuftelin1 gene.

Genetic diversity and population structure of watermelon (Citrullus sp.) genotypes.

Genetic polymorphism amid plant species is a crucial factor for plant improvement and maintaining their biodiversity. Evaluation of genetic diversity amongst plant species is significant to deal with the environmental stress conditions and their effective involvement in the breeding programs. Hence, in present study, an attempt has been made towards the genetic assessment of individual and bulked populations of 25 watermelon genotypes, belonging to Citroides (citron watermelon) and Lanatus (dessert watermelon) group from Konya, Thrace, Turkmenistan, Saudi Arabia and Turkey. The employed Random Amplified Polymorphic DNA (RAPD) and Inter-Simple Sequence Polymorphism (ISSR) marker systems provided 69.4 and 95.4% polymorphisms, respectively. Different clustering methods showed clear grouping of the genotypes based on the geographical origin and species. Citron genotypes from Turkmenistan stood apart from all the Turkish Lanatus genotypes. However, Saudi Arab Lanatus genotype grouped with native Turkish varieties indicating the genetic linkage. Among all the Turkmenistan Citron genotypes, Turkmenistan-11 was the most distinct form. Moreover, sufficient genetic variation was found between the commercial and native Lanatus genotypes of Turkey as well as Citron genotypes of Turkmenistan. Hence, it will be beneficial to include these genotypes in the future breeding programs to transfer disease-resistant alleles from Citron to Lanatus genotypes.

Investigation of matrix metalloproteinase-1--1607 1G/2G polymorphism in a Turkish population with periodontitis.

AIM: Matrix metalloproteinase-1 (MMP-1) is a proteolytic enzyme that degrades extracellular matrix and plays a fundamental role during destruction of periodontal tissues. The aim of this study was to examine the association between MMP-1 -1607 1G/2G polymorphism and chronic periodontitis susceptibility in a Turkish population. MATERIAL AND METHODS: A total of 180 subjects were enrolled in this study. All the subjects received a periodontal examination including full-mouth clinical attachment loss measurements, probing depths, plaque index scores, gingival index scores and radiographic bone loss ratios. Three groups formed according to periodontal conditions were healthy, moderate periodontitis and severe periodontitis groups. MMP-1 -1607 1G/2G gene promoter polymorphism was genotyped using a polymerase chain reaction-restriction fragment length polymorphism method. RESULTS: Analysis of the polymorphism showed no differences in distribution of the MMP-1 -1607 1G/2G polymorphism among healthy, moderate periodontitis and severe periodontitis groups (p>0.05). When the groups were further stratified by smoking status, we found no significant differences in genotype distributions, allele frequencies and carriage rates among any groups either (p>0.05). CONCLUSIONS: On the basis of the results, no significant association is found for the MMP-1 -1607 1G/2G polymorphism with susceptibility to periodontitis. Moreover, smoking status did not seem to affect this result.

Porphyromonas gingivalis Lipopolysaccharide Induces a Pro-inflammatory Human Gingival Fibroblast Phenotype.

Human gingival fibroblasts (HGFs) are the major constituents of the gingival tissues responsible for the synthesis and degradation of the connective tissue while actively participating in immune reactions and inflammation. The aim of this study was to test the impact of lipopolysaccharide (LPS) from Porphyromonas gingivalis (P. gingivalis) on human gingival fibroblasts. Human gingival fibroblasts were treated with different P. gingivalis LPS concentrations. Cell survival rate was evaluated with 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) after 24 h. Cell proliferation was determined by counting cells on days 3 and 12. Expression of matrix metalloproteinases (MMPs), tissue inhibitors of MMPs (TIMPs), and pro-inflammatory cytokine transcripts in HGFs was determined by quantitative PCR (Q-PCR) analysis on days 3 and 8. P. gingivalis LPS decreased cell proliferation on day 3 (p < 0.05) compared to the control group without significantly impacting the cell survival (p > 0.05).The experiments showed that P. gingivalis LPS dose-dependently and differentially modulated the expression of MMP-1, 2, and 3 and TIMP-1 and 2 on days 3 and 8. TIMP-1 expression was significantly induced in P. gingivalis LPS-treated cells while TIMP-2 was increased in response to 10 and 30 ng/ml of LPS on day 3. P. gingivalis LPS induced up-regulation of MMP-1/TIMP-1 ratio on day 3 and increased MMP-2/TIMP-2 ratio on day 8 dose-dependently. Expression of interleukin (IL)-6 and IL-8 was stimulated at higher concentrations (1000 and 3000 ng/ml) of LPS. These findings demonstrate that P. gingivalis LPS suppresses cell proliferation and leads to increased pro-inflammatory changes in HGFs, suggesting that P. gingivalis LPS-induced modification of phenotypic and inflammatory characteristics in HGF could potentially be a pathogenic mechanism underlying the tissue destruction.

Ancient DNA from 8400 Year-Old Çatalhöyük Wheat: Implications for the Origin of Neolithic Agriculture.

Human history was transformed with the advent of agriculture in the Fertile Crescent with wheat as one of the founding crops. Although the Fertile Crescent is renowned as the center of wheat domestication, archaeological studies have shown the crucial involvement of Çatalhöyük in this process. This site first gained attention during the 1961-65 excavations due to the recovery of primitive hexaploid wheat. However, despite the seeds being well preserved, a detailed archaeobotanical description of the samples is missing. In this article, we report on the DNA isolation, amplification and sequencing of ancient DNA of charred wheat grains from Çatalhöyük and other Turkish archaeological sites and the comparison of these wheat grains with contemporary wheat species including T. monococcum, T. dicoccum, T. dicoccoides, T. durum and T. aestivum at HMW glutenin protein loci. These ancient samples represent the oldest wheat sample sequenced to date and the first ancient wheat sample from the Middle East. Remarkably, the sequence analysis of the short DNA fragments preserved in seeds that are approximately 8400 years old showed that the Çatalhöyük wheat stock contained hexaploid wheat, which is similar to contemporary hexaploid wheat species including both naked (T. aestivum) and hulled (T. spelta) wheat. This suggests an early transitory state of hexaploid wheat agriculture from the Fertile Crescent towards Europe spanning present-day Turkey.

Assessment of genetic variability for grain nutrients from diverse regions: potential for wheat improvement.

BACKGROUND: A total of 150 bread wheat genotypes representing 121 Indian and 29 Turkish origin were screened for nutrient concentrations and grain protein content. Elemental and grain protein composition were studied by Inductively Coupled Plasma-Atomic Emission Spectrophotometer and LECO analyser, respectively. The study was performed to determine the variability in nutrient concentrations present in the collected wheat genetic material from two countries. RESULTS: Several fold variations among genotypes existed for almost all the elements. Three major components of principal component analysis (PCA) revealed 60.8% variation among the genotypes. Nutrient variables segregated into two groups, one group containing all the macroelements except sulphur; and another cluster containing proteins and all the microelements except Zn and Mn. Pearson correlation analysis and heat-map were in accordance with each other determining strong positive association between P-K, Mn-Zn, Mg-S and Cu-protein content. Also, PCA and hierarchical grouping divided all the Indian and Turkish genotypes in two main clusters. CONCLUSIONS: Nutritional profile differentiated the genotypes from two countries into separate groups. However, some of the varieties were closely associated and indicated the success of global wheat exchange programs. While most of the correlations were in agreement with the previous studies, non-association of zinc with grain protein content directed towards its control by some other genetic factors. Some of the experimental wheat varieties with promising nutrient content have been suggested for future wheat advancement programs. Results obtained will be supportive for breeders involved in wheat biofortification programs, food industries and people relying on whole grain wheat products.

Identification of the difference in extracellular matrix and adhesion molecules of cultured human gingival fibroblasts versus juvenile hyaline fibromatosis gingival fibroblasts using cDNA microarray analysis.

BACKGROUND: A difference from the normal range in collagen profile and perivascular hyaline deposition in the dermis and gingiva has been demonstrated histopathologically in juvenile hyaline fibromatosis (JHF), which is an autosomal recessive disease. The aim of this study was to understand the mechanism of gingival overgrowth in JHF, and to observe differences in the expression of genes regulating extracellular matrix organization. METHODS: Human gingival fibroblasts (GF) were obtained from individuals who have clinically healthy gingival tissue. JHF-GF were obtained from a patient who underwent a gingivectomy. Cultured fibroblast cells were examined visually using a phase contrast microscope. Total RNA from both cell types was isolated, and after biotin-deoxyuridine triphosphate (dUTP) labeling of cDNA, hybridization was performed with a pathway-specific gene expression profiling array membrane. Extracellular matrix (ECM) and adhesion molecule (AM) mRNA expressions in GF and JHF-GF were analyzed, and microarray data on genes modulating ECM remodeling were confirmed with reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Cell morphology differences were observed between fibroblast types. Although type I collagen gene expression levels were almost the same, decreased type IV collagen expression was noted in JHF-GF versus GF. Decreased matrix metalloproteinase (MMP) and increased tissue inhibitor of matrix metalloproteinase (TIMP) transcripts were noted in JHF-GF versus GF. Increased fibronectin and decreased laminin mRNA expression were observed in JHF-GF when compared to GF. The present findings suggest that GF and JHF-GF differ not only morphologically but also in the expression level of ECM and AM genes involving connective tissue turnover and remodeling. CONCLUSIONS: Results from these analyses may be helpful to clarify the nature of overgrowth mechanisms, especially regarding enzymes and their inhibitors. This information is important in understanding the remodeling of ECM. The gingival overgrowth that is observed in JHF patients may be explained by a decreased level of MMPs and increased blockage of MMPs with TIMPs.

Dexamethasone and basic-fibroblast growth factor regulate markers of mineralization in cementoblasts in vitro.

BACKGROUND: The aim of this study was to determine the effects of basic-fibroblast growth factor (b-FGF) and/or dexamethasone (Dex) on cementoblasts in vitro. METHODS: Murine cementoblasts were treated as follows: 1) 5% FBS (fetal bovine serum) + ascorbic acid (AA, 50 microg/ml, control); 2) 5% FBS + Dex (10(7)M) + AA; 3) 5% FBS + b-FGF (50 ng/ml)+AA; or 4) 5% FBS + Dex (10(7) M) + b-FGF (50 ng/ml)+AA and then evaluated by Northern analysis for changes in specific genes and by von Kossa stain for changes in mineral nodule formation. RESULTS: Mitotic activity: b-FGF stimulated DNA synthesis significantly versus negative control. Gene expression: osteocalcin (OCN): Dex or b-FGF or the combination resulted in a decrease in expression versus control. Bone sialoprotein (BSP): Dex increased expression of BSP mRNA levels, b-FGF decreased transcript for BSP at 6 and 24 hours. Long-term (8 days) Dex, b-FGF, or Dex plus b-FGF caused a decrease in BSP expression versus control; osteopontin (OPN): both Dex and b-FGF increased transcripts for OPN seen by 6 hours, with a greater increase noted with b-FGF versus Dex. No apparent additive effect of Dex with b-FGF was noted; matrix gamma-carboxyglutamic acid protein (MGP): b-FGF induced transcripts for MGP and addition of Dex increased this effect, while Dex alone had no effect on expression. Biomineralization: Dex increased cementoblast- mediated biomineralization, while b-FGF blocked this activity, and addition of Dex to b-FGF did not alter FGF associated inhibition. CONCLUSION: Dex and FGF alone and in combination alter cementoblast behavior, but additional studies are required to determine whether these factors have beneficial effects at the clinical level.

Genetic diversity and population structure of wheat in India and Turkey.

Genetic diversity among plant species offers prospects for improving the plant characteristics. Its assessment is necessary to help tackle the threats of environmental fluctuations and for the effective exploitation of genetic resources in breeding programmes. Although wheat is one of the most thoroughly studied crops in terms of genetic polymorphism studies, phylogenetic affinities of Indian and Turkish Triticum species have not been assessed to date. In this study, genetic association of 95 tetraploid and hexaploid wheat genotypes originating from India and Turkey was determined for the first time. Combined analysis of random amplified polymorphic DNA and inter-simple sequence repeat markers disclosed 177 polymorphic bands, and both the dendrogram and two-dimensional scatterplot showed similar groupings of the wheat genotypes. Turkish hexaploid varieties were basically divided into two clusters, one group showed its close association with Indian hexaploid varieties and the other with Indian tetraploid varieties. Analysis of molecular variance revealed high (77 %) genetic variation within Indian and Turkish populations. Population structure analysis elucidated distinct clustering of wheat genotypes on the basis of both geographical origin and ploidy. The results revealed in this study will support worldwide wheat breeding programmes and assist in achieving the target of sustainable wheat production.

Comparison of mesenchymal stem cells isolated from pulp and periodontal ligament.

BACKGROUND: Cell-based therapy using mesenchymal stem cells (MSCs) seems promising to obtain regeneration of dental tissues. A comparison of tissue sources, including periodontal ligament (PDL) versus pulp (P), could provide critical information to select an appropriate MSC population for designing predictable regenerative therapies. The purpose of this study is to compare the proliferation and stemness and the MSC-specific and mineralized tissue-specific gene expression of P-MSCs and PDL-MSCs. METHODS: MSCs were obtained from PDL and P tissue of premolars (n = 3) extracted for orthodontic reasons. MSC proliferation was evaluated using a real-time cell analyzer for 160 hours. Telomerase activity was evaluated by a telomeric repeat amplification protocol assay based on enzyme-linked immunosorbent assay. Total RNA was isolated from the MSCs on day 3. A polymerase chain reaction (PCR) array was used to compare the expression of MSC-specific genes. The expression of mineralized tissue-associated genes, including Type I collagen (COL I), runt-related transcription factor 2 (RunX2), bone sialoprotein (BSP), and osteocalcin (OCN) messenger RNA (mRNA), was evaluated using quantitative real-time PCR. RESULTS: Higher proliferation potential and telomerase activity were observed in the P-MSCs compared to PDL-MSCs of premolar teeth. Fourteen of 84 genes related to MSCs were expressed differently in the PDL-MSCs versus the P-MSCs. The expressions of bone morphogenetic protein 2 (BMP2) and BMP6; sex-determining region Y-box 9 (SOX9); integrin, alpha 6 (ITGA6); melanoma cell adhesion molecule (MCAM); phosphatidylinositol glycan anchor biosynthesis, class S (PIGS); prominin 1 (PROM1); ribosomal protein L13A (RPL13A); and microphthalmia-associated transcription factor (MITF) were higher in the P-MSCs compared to the PDL-MSCs, and higher expression of matrix metalloproteinase 2 (MMP2), interleukin (IL)-6, insulin (INS), alanyl (membrane) aminopeptidase (ANPEP), and IL-10 were observed in the PDL-MSCs. However, there was no statistically significant difference in the expression of mineralized tissue-associated genes, including BSP and RunX2, between the P-MSCs and the PDL-MSCs. Higher expression of COL I and lower expression of OCN mRNA transcripts were noted in the PDL-MSCs compared to the P-MSCs. CONCLUSIONS: The results of this study suggest that MSCs isolated from P and PDL tissues show different cellular behavior. To increase the predictability of MSC-based regenerative treatment, differences in dental tissue-derived MSCs and favorable aspects of cell sources should be further clarified.

Dietary boron does not affect tooth strength, micro-hardness, and density, but affects tooth mineral composition and alveolar bone mineral density in rabbits fed a high-energy diet.

The objective of this study was to determine whether dietary boron (B) affects the strength, density and mineral composition of teeth and mineral density of alveolar bone in rabbits with apparent obesity induced by a high-energy diet. Sixty female, 8-month-old, New Zealand rabbits were randomly assigned for 7 months into five groups as follows: (1) control 1, fed alfalfa hay only (5.91 MJ/kg and 57.5 mg B/kg); (2) control 2, high energy diet (11.76 MJ and 3.88 mg B/kg); (3) B10, high energy diet + 10 mg B gavage/kg body weight/96 h; (4) B30, high energy diet + 30 mg B gavage/kg body weight/96 h; (5) B50, high energy diet + 50 mg B gavage/kg body weight/96 h. Maxillary incisor teeth of the rabbits were evaluated for compression strength, mineral composition, and micro-hardness. Enamel, dentin, cementum and pulp tissue were examined histologically. Mineral densities of the incisor teeth and surrounding alveolar bone were determined by using micro-CT. When compared to controls, the different boron treatments did not significantly affect compression strength, and micro-hardness of the teeth, although the B content of teeth increased in a dose-dependent manner. Compared to control 1, B50 teeth had decreased phosphorus (P) concentrations. Histological examination revealed that teeth structure (shape and thickness of the enamel, dentin, cementum and pulp) was similar in the B-treated and control rabbits. Micro CT evaluation revealed greater alveolar bone mineral density in B10 and B30 groups than in controls. Alveolar bone density of the B50 group was not different than the controls. Although the B treatments did not affect teeth structure, strength, mineral density and micro-hardness, increasing B intake altered the mineral composition of teeth, and, in moderate amounts, had beneficial effects on surrounding alveolar bone.

Bone morphogenetic protein-2, -6, and -7 differently regulate osteogenic differentiation of human periodontal ligament stem cells.

The utility of adult stem cells for bone regeneration may be an attractive alternative in the treatment of extensive injury, congenital malformations, or diseases causing large bone defects. To create an environment that is supportive of bone formation, signals from molecules such as the bone morphogenetic proteins (BMPs) are required to engineer fully viable and functional bone. We therefore determined whether BMP-2, -6, and -7 differentially regulate the (1) proliferation, (2) mineralization, and (3) mRNA expression of bone/mineralized tissue associated genes of human periodontal ligament stem cells (hPDLSCs), which were obtained from periodontal ligament tissue of human impacted third molars. hPDLSCs from six participants were isolated and characterized using histochemical and immunohistochemical methods. A real-time cell analyzer was used to evaluate the effects of BMP-2, -6, and -7 on the proliferation of hPDLSCs. hPDLSCs were treated with Dulbecco's modified Eagle's medium containing different concentrations of BMP-2, -6, and -7 (10, 25, 50, 100 ng/mL) and monitored for 264 hours. After dose-response experiments, 50 and 100 ng/mL concentrations of BMPs were used to measure bone/mineralized tissue-associated gene expression. Type I collagen, bone sialoprotein, osteocalcin, osteopontin, and osteoblastic transcription factor Runx2 mRNA expression of hPDLSCs treated with BMP-2, -6, and -7, were evaluated using quantitative RT-PCR. Biomineralization of hPDLSCs was assessed using von Kossa staining. This study demonstrated that BMPs at various concentrations differently regulate the proliferation, mineralization, and mRNA expression of bone/mineralized tissue associated genes in hPDLSCs. BMPs regulate hPDLSC proliferation in a time and dose-dependent manner when compared to an untreated control group. BMPs induced bone/mineralized tissue-associated gene mRNA expression and biomineralization of hPDLSCs. The most pronounced induction occurred in the BMP-6 group in the biomineralization of the hPDLSCs. Our data suggest that BMP-2, -6, and -7 are potent regulators of hPDLSC gene expression and biomineralization. Employing BMPs with hPDLSCs isolated from periodontal ligament tissues provides a promising strategy for bone tissue engineering.

Boron enhances strength and alters mineral composition of bone in rabbits fed a high energy diet.

An experiment was performed to determine whether boron had a beneficial effect on bone strength and composition in rabbits with apparent adiposity induced by a high energy diet. Sixty female New Zealand rabbits, aged 8 months, were randomly divided into five groups with the following treatments for seven months: control 1, fed alfalfa hay only (5.91 MJ/kg); control 2, high energy diet (11.76 MJ and 3.88 mg boron/kg); B10, high energy diet+10 mg/kg body weight boron gavage/96 h; B30, high energy diet+30 mg/kg body weight boron gavage/96 h; B50, high energy diet+50mg/kg body weight boron gavage/96 h. Bone boron concentrations were lowest in rabbits fed the high energy diet without boron supplementation, which suggested an inferior boron status. Femur maximum breaking force was highest in the B50 rabbits. Tibia compression strength was highest in B30 and B50 rabbits. All boron treatments significantly increased calcium and magnesium concentrations, and the B30 and B50 treatments increased the phosphorus concentration in tibia of rabbits fed the high energy diet. The B30 treatment significantly increased calcium, phosphorus and magnesium concentrations in femur of rabbits fed the high energy diet. Principal component analysis of the tibia minerals showed that the three boron treatments formed a separate cluster from controls. Discriminant analysis suggested that the concentrations of the minerals in femur could predict boron treatment. The findings indicate boron has beneficial effects on bone strength and mineral composition in rabbits fed a high energy diet.

Osteogenic differentiation of MC3T3-E1 cells on different titanium surfaces.

mRNA expressions related to osteogenic differentiation of MC3T3-E1 cells on electro-polished smooth (S), sandblasted small-grit (SSG) and sandblasted large-grit (SLG) surfaces of titanium alloys were investigated in vitro. Gene expression profiles of cells were evaluated using the RT2 Profiler PCR microarray on day 7. Mineralizing tissue-associated proteins, differentiation factors and extracellular matrix enzymes mRNA expressions were measured using Q-PCR. SLG surface upregulated 23 genes over twofolds and downregulated 3 genes when compared to the S surface. In comparison to the SSG surface, at least a twofold increase in 25 genes was observed in the SLG surface. BSP, OCN, OPN, COL I and ALP mRNA expressions increased in the SLG group when compared to the S and the SSG groups. BMP-2, BMP-6 and TGF-ß mRNA expressions increased in both the SSG and the SLG surfaces. MMP-2 and MMP-9 mRNA expressions increased as the surface roughness increased. This study demonstrated that surface roughness of titanium implants has a significant effect on cellular behavior and SLG surface apparently increased gene expressions related to osteogenesis when compared to the S and the SSG surfaces.

Boron regulates mineralized tissue-associated proteins in osteoblasts (MC3T3-E1).

The aim of this study was to determine the effects of boron (B) on the cell-survival, proliferation, mineralization and mRNA expression of mineralized tissue-associated proteins. Additionally, determination of the effects of B on the BMP-4, -6 and -7 protein levels of pre-osteoblastic cells (MC3T3-E1) was also intended. The effects of B (pH 7.0) concentrations (0, 0.1, 1, 10, 100, 1000, 2000, 4000, 8000 and 10,000 ng/ml) on the survival of the cells were evaluated at 24 and 96 hrs with MTT assay. To evaluate the proliferation in long term, MC3T3-E1 cells were treated with different concentrations of B (0, 0.1, 1, 10, 100 and 1000 ng/ml) and were counted on days 2, 5, and 14. While in short term, decreased cell survival rate was observed at 1000 ng/ml and above, at long term no statistically significant difference was detected in different B concentrations applied. Slight decreases at the proliferation of the B-treated groups were determined on days 5 and 14 but one-way analysis of variance revealed that the difference was statistically insignificant. In mineralization assay, increased mineralized nodules were apparently observed in B treatment (1 and 10 ng/ml concentrations) groups. Based on quantitative RT-PCR results, remarkable regulation in favor of osteoblastic function for Collagen type I (COL I), Osteopontin (OPN), Bone Sialoprotein (BSP), Osteocalcin (OCN) and RunX2 mRNA expressions were observed in B treatment groups in comparison with untreated control groups. Increased BMP-4, -6 and -7 protein levels were detected at 0.1, 1, 10 and 100 ng/ml B concentrations. Results of the study suggest that at the molecular level B displays important roles on bone metabolism and may find novel usages at the regenerative medicine.