Joana M. Ramis

The glutamine 27 glutamic acid polymorphism of the β2-adrenoceptor gene is associated with abdominal obesity and greater risk of impaired glucose tolerance in men but not in women: a population-based study in Spain

objetive  Given the important role of the β2‐adrenoceptor (β2‐AR) in lipid mobilization and the lack of studies in Southern European countries, the aim of this study was to investigate the role of the glutamine 27 glutamic acid (Gln27Glu) β2‐AR polymorphism in the susceptibility to obesity and its metabolic complications in a population‐based nationwide multicentre study in Spain, especially focusing on the hypothetical influence of gender.

Quercitrin and taxifolin stimulate osteoblast differentiation in MC3T3-E1 cells and inhibit osteoclastogenesis in RAW 264.7 cells.

Flavonoids are natural antioxidants that positively influence bone metabolism. The present study screened among different flavonoids to identify biomolecules for potential use in bone regeneration. For this purpose, we used MC3T3-E1 and RAW264.7 cells to evaluate their effect on cell viability and cell differentiation. First, different doses of chrysin, diosmetin, galangin, quercitrin and taxifolin were analyzed to determine the optimum concentration to induce osteoblast differentiation. After 48h of treatment, doses ≥100μM of diosmetin and galangin and also 500μM taxifolin revealed a toxic effect on cells. The same effect was observed in cells treated with doses ≥100μM of chrysin after 14 days of treatment. However, the safe doses of quercitrin (200 and 500μM) and taxifolin (100 and 200μM) induced bone sialoprotein and osteocalcin mRNA expression. Also higher osteocalcin secreted levels were determined in 100μM taxifolin osteoblast treated samples when compared with the control ones. On the other hand, quercitrin and taxifolin decreased Rankl gene expression in osteoblasts, suggesting an inhibition of osteoclast formation. Indeed, osteoclastogenesis suppression by quercitrin and taxifolin treatment was observed in RAW264.7 cells. Based on these findings, the present study demonstrates that quercitrin and taxifolin promote osteoblast differentiation in MC3T3-E1 cells and also inhibit osteoclastogenesis in RAW264.7 cells, showing a positive effect of these flavonoids on bone metabolism.

Sinus Graft With Safescraper: 5-Year Results

PURPOSE In the procedure of sinus floor elevation, autogenous bone, allogenic grafts, and several other bone substitutes are used. However, autogenous bone is still considered the gold standard. Donor sites for autogenous bone are generally the iliac crest, oral cavity, calvarium bone, and tibia. In this work the experience with the use of a Safescraper device for harvesting of autogenous bone is reported and a decision-making algorithm for grafting in sinus floor elevation procedures is proposed. MATERIALS AND METHODS Forty sinus augmentation procedures were performed in 34 patients. All sinuses were filled with a mixture of autogenous bone and bovine hydroxyapatite. A Safescraper device was used to harvest autologous bone from the maxillary area. Platelet-rich plasma was used to sustain bone placement. Sixty-five dental implants were placed at 4 months with a flapless procedure. A clinical and radiological 5-year retrospective case series of a cohort is reported. RESULTS In all cases new bone formation was confirmed radiologically and implant placement was performed successfully. Analysis of samples obtained by biopsy with histology and microcomputed tomography showed the presence of mature bone. Healing problems were observed in only 1 case. CONCLUSIONS Sinus augmentation with bone grafts obtained from oral cavity with a bone scraper device has the advantage of providing autogenous bone without the need for an extra surgical approach. This procedure yields satisfactory results in bone formation, implant survival, and patient satisfaction. When combined with a flapless approach for implant placement, a decrease in the morbidity of the entire process is achieved.

Xnrs and Activin Regulate Distinct Genes during Xenopus Development: Activin Regulates Cell Division

Background The mesoderm of the amphibian embryo is formed through an inductive interaction in which vegetal cells of the blastula-staged embryo act on overlying equatorial cells. Candidate mesoderm-inducing factors include members of the transforming growth factor type β family such as Vg1, activin B, the nodal-related proteins and derrière. Methodology and Principle Findings Microarray analysis reveals different functions for activin B and the nodal-related proteins during early Xenopus development. Inhibition of nodal-related protein function causes the down-regulation of regionally expressed genes such as chordin, dickkopf and XSox17α/β, while genes that are mis-regulated in the absence of activin B tend to be more widely expressed and, interestingly, include several that are involved in cell cycle regulation. Consistent with the latter observation, cells of the involuting dorsal axial mesoderm, which normally undergo cell cycle arrest, continue to proliferate when the function of activin B is inhibited. Conclusions/Significance These observations reveal distinct functions for these two classes of the TGF-β family during early Xenopus development, and in doing so identify a new role for activin B during gastrulation.

Differential response of human gingival fibroblasts to titanium- and titanium-zirconium-modified surfaces.

BACKGROUND AND OBJECTIVE Gingival fibroblasts are responsible for the constant adaptation, wound healing and regeneration of gingival connective tissue. New titanium-zirconium (TiZr) abutment surfaces have been designed to improve soft tissue integration and reduce implant failure compared with titanium (Ti). The aim of the present study was first to characterize a primary human gingival fibroblast (HGF) model and secondly to evaluate their differential response to Ti and TiZr polished (P), machined (M) and machined + acid-etched (modMA) surfaces, respectively. MATERIAL AND METHODS HGF were cultured on tissue culture plastic or on the different Ti and TiZr surfaces. Cell morphology was evaluated through confocal and scanning electron microscopy. A wound healing assay was performed to evaluate the capacity of HGF to close a scratch. The expression of genes was evaluated by real-time RT-PCR, addressing: (i) extracellular matrix organization and turnover; (ii) inflammation; (iii) cell adhesion and structure; and (iv) wound healing. Finally, cells on Ti/TiZr surfaces were immunostained with anti-ITGB3 antibodies to analyze integrin β3 production. Matrix metalloproteinase-1 (MMP1) and inhibitor of metallopeptidases-1 (TIMP1) production were analyzed by enzyme-linked immunosorbent assays. RESULTS On tissue culture plastic, HGF showed no differences between donors on cell proliferation and on the ability for wound closure; α-smooth muscle actin was overexpressed on scratched monolayers. The differentiation profile showed increased production of extracellular matrix components. Ti and TiZr showed similar biocompatibility with HGF. TiZr increased integrin-β3 mRNA and protein levels, compared with Ti. Cells on TiZr surfaces showed higher MMP1 protein than Ti surfaces, although similar TIMP1 protein production. In this in vitro experiment, P and M surfaces from both Ti and TiZr showed better HGF growth than modMA. CONCLUSION Taking into account the better mechanical properties and bioactivity of TiZr compared with Ti, the results of the present study show that TiZr is a potential clinical candidate for soft tissue integration and implant success.

Effect of enamel matrix derivative and of proline-rich synthetic peptides on the differentiation of human mesenchymal stem cells toward the osteogenic lineage.

With the aim of discovering new molecules for induction of bone formation and biomineralization, combination of bioinformatics and simulation methods were used to design the structure of artificial peptides based on proline-rich domains of enamel matrix proteins. In this study, the effect of such peptides on the differentiation toward the osteogenic lineage of human umbilical cord mesenchymal stem cells (hUCMSCs) was evaluated with or without osteogenic supplements (hydrocortisone, β-glycerol phosphate, and ascorbic acid) and compared to the effect of the commercially available enamel matrix derivative (EMD). It was hypothesized that the differentiation toward the osteogenic lineage of hUCMSCs would be promoted by the treatment with the synthetic peptides when combined with differentiation media, or it could even be directed exclusively by the synthetic peptides. Osteoinductivity was assessed by cell proliferation, bone morphogenetic protein-2 secretion, and gene expression of osteogenic markers after 1, 3, and 14 days of treatment. All peptides were safe with the dosages used, showing lower cell toxicity. P2, P4, and P6 reduced cell proliferation with growing media by 10%-15%. Higher expression of early osteoblast markers was found after 3 days of treatment with EMD in combination with osteogenic supplements, while after 14 days of treatment, cells treated by the different synthetic peptides in combination with osteogenic supplements showed higher osteocalcin mRNA levels. We can conclude that osteogenic differentiation of hUCMSCs is promoted by short-term EMD treatment in combination with osteogenic supplements and by long-term treatment by the synthetic peptides in combination with osteogenic supplements, showing similar results for all the peptide variants analyzed in this study.

Flavonoid-Modified Surfaces: Multifunctional Bioactive Biomaterials with Osteopromotive, Anti-Inflammatory, and Anti-Fibrotic Potential

Flavonoids are small polyphenolic molecules of natural origin with antioxidant, anti-inflammatory, and antibacterial properties. Here, a bioactive surface based on the covalent immobilization of flavonoids taxifolin and quercitrin on titanium substrates is presented, using (3-aminopropyl)triethoxysilane (APTES) as coupling agent. FTIR and XPS measurements confirm the grafting of the flavonoids to the surfaces. Using 2-aminoethyl diphenylborinate (DPBA, a flavonoid-specific dye), the modified surfaces are imaged by fluorescence microscopy. The bioactivity of the flavonoid-modified surfaces is evaluated in vitro with human umbilical cord derived mesenchymal stem cells (hUC-MSCs) and human gingival fibroblasts (HGFs) and compared to that of simple flavonoid coatings prepared by drop casting. Flavonoid-modified surfaces show anti-inflammatory and anti-fibrotic potential on HGF. In addition, Ti surfaces covalently functionalized with flavonoids promote the differentiation of hUC-MSCs to osteoblasts--enhancing the expression of osteogenic markers, increasing alkaline phosphatase activity and calcium deposition; while drop-casted surfaces do not. These findings could have a high impact in the development of advanced implantable medical devices like bone implants. Given the broad range of bioactivities of flavonoid compounds, these surfaces are ready to be explored for other biomedical applications, e.g., as stent surface or tumor-targeted functionalized nanoparticles for cardiovascular or cancer therapies.

Anti-fibrotic and anti-inflammatory properties of melatonin on human gingival fibroblasts in vitro.

Melatonin (MEL) has been proposed as a therapeutic agent for the oral cavity, due to its antioxidant and anti-inflammatory effects since periodontal diseases are aggravated by free radicals, and by disproportionate immunological response to plaque microorganism. In addition, MEL promotes bone formation. This study aimed to investigate the effects of MEL and 5-methoxytryptophol (5-MTX), an indole derivative related to MEL, on the growth rate of Staphylococcus epidermidis and on human gingival fibroblasts (HGF) for potential use in periodontal applications. HGF were treated with MEL and 5-MTX and the effects were evaluated on cell viability, gene expression, collagen production, wound healing and matrix metalloproteinase-1/tissue inhibitor of metalloproteinases-1 (MMP1/TIMP1) production. MEL showed the most promising biological effects in relation to periodontal applications. Thus, MEL was not toxic for HGF, increased collagen IIIα1, decorin and IL10, it down-regulated the expression of pro-fibrotic markers during wound healing, decreased the MMP1/TIMP1protein ratio. These results suggest that MEL could contribute to protect and recover the integrity of gingival tissues, thus, displaying a potential use for periodontal disease treatment or to functionalize dental implant abutments to improve soft tissue integration.

Bioinspired Quercitrin Nanocoatings: A Fluorescence-Based Method for Their Surface Quantification, and Their Effect on Stem Cell Adhesion and Differentiation to the Osteoblastic Lineage

Polyphenol-based coatings have several potential applications in medical devices, such as cardiovascular stents, contrast agents, drug delivery systems, or bone implants, due to the multiple bioactive functionalities of these compounds. In a previous study, we fabricated titanium surfaces functionalized with flavonoids through covalent chemistry, and observed their osteogenic, anti-inflammatory, and antifibrotic properties in vitro. In this work, we report a fluorescence-based method for the quantification of the amount of flavonoid grafted onto the surfaces, using 2-aminoethyl diphenylborinate, a boronic ester that spontaneously forms a fluorescent complex with flavonoids. The method is sensitive, simple, rapid, and easy to perform with routine equipment, and could be applied to determine the surface coverage of other plant-derived polyphenol-based coatings. Besides, we evaluated an approach based on reductive amination to covalently graft the flavonoid quercitrin to Ti substrates, and optimized the grafting conditions. Depending on the reaction conditions, the amount of quercitrin grafted was between 64 ± 10 and 842 ± 361 nmol on 6.2 mm Ti coins. Finally, we evaluated the in vitro behavior of bone-marrow-derived human mesenchymal stem cells cultured on the quercitrin nanocoated Ti surfaces. The surfaces functionalized with quercitrin showed a faster stem cell adhesion than control surfaces, probably due to the presence of the catechol groups of quercitrin on the surfaces. A rapid cell adhesion is crucial for the successful performance of an implant. Furthermore, quercitrin-nanocoated surfaces enhanced the mineralization of the cells after 21 days of cell culture. These results indicate that quercitrin nanocoatings could promote the rapid osteointegration of bone implants.

Quercitrin for periodontal regeneration: effects on human gingival fibroblasts and mesenchymal stem cells.

Periodontal disease (PD) is the result of an infection and chronic inflammation of the gingiva that may lead to its destruction and, in severe cases, alveolar bone and tooth loss. The ultimate goal of periodontal treatment is to achieve periodontal soft and hard tissues regeneration. We previously selected quercitrin, a catechol-containing flavonoid, as a potential agent for periodontal applications. In this study, we tested the ability of quercitrin to alter biomarker production involved in periodontal regeneration on primary human gingival fibroblasts (hGF) and primary human mesenchymal stem cells (hMSC) cultured under basal and inflammatory conditions. To mimic PD inflammatory status, interleukin-1 beta (IL-1β) was used. The expression of different genes related to inflammation and extracellular matrix were evaluated and prostaglandin E2 (PGE2) production was quantified in hGFs; alkaline phosphatase (ALP) activity and calcium content were analysed in hMSCs. Quercitrin decreased the release of the inflammatory mediator PGE2 and partially re-established the impaired collagen metabolism induced by IL-1β treatment in hGFs. Quercitrin also increased ALP activity and mineralization in hMSCs, thus, it increased hMSCs differentiation towards the osteoblastic lineage. These findings suggest quercitrin as a novel bioactive molecule with application to enhance both soft and hard tissue regeneration of the periodontium.