Sustained Release of Vitamin D3 Enhanced Osseointegration Capacity: An Experimental Sheep Study

This study aimed to investigate the effect of sustained-release vitamin D loaded in poly-lactic acid (PLA) nanoparticles and applied to grafting materials around titanium (ti) dental implants. A total of 48 implants were inserted into the standardized bone defects created in the iliac crest of 6 sheep, divided into 4 different experimental sites (empty control, autografted, xenografted, and autograft + xenografted). Vitamin D3, which was encapsulated by PLA nanoparticles, was prepared and applied in half of the defects and left to heal for 3 and 6 weeks. New bone formation (NBF%) and bone-implant contact (BIC%) values were evaluated by histologic and histomorphometric analyses (P < 0.05). Nanoparticles with a yield of 80.30% ± 2.14% and high encapsulation efficiency of 72.99% ± 2.20% were achieved. In all sections, osseointegration was observed, with no signs of inflammation, necrosis, or foreign body reaction. NBF% and BIC% were significantly higher in vitamin D3–loaded groups (P < 0.001). In both healing periods, the highest NBF% and BIC% have been recorded in the autograft + xenograft groups. (For the respective third and sixth weeks: the NBF% was 49.63 ± 1.53 and 74.25 ± 0.96, and BIC% was 54.26 ± 0.66 and 82.59 ± 2.09, respectively; P < 0.001). Sustained-release of vitamin D loaded into the PLA system demonstrated high biocompatibility, favorable sustained release of vitamin D3, and improved NBF% and BIC% around ti implants placed in box-shaped sheep iliac crest defects. Further investigations are required for their clinical applicability.

Selenoprotein T Protects Endothelial Cells against Lipopolysaccharide-Induced Activation and Apoptosis

Sepsis is an exaggerated immune response upon infection with lipopolysaccharide (LPS) as the main causative agent. LPS-induced activation and apoptosis of endothelial cells (EC) can lead to organ dysfunction and finally organ failure. We previously demonstrated that the first twenty amino acids of the Apurinic/Apyrimidinic Endodeoxyribonuclease 1 (APEX1) are sufficient to inhibit EC apoptosis. To identify genes whose regulation by LPS is affected by this N-terminal APEX1 peptide, EC were transduced with an expression vector for the APEX1 peptide or an empty control vector and treated with LPS. Following RNA deep sequencing, genes upregulated in LPS-treated EC expressing the APEX1 peptide were identified bioinformatically. Selected candidates were validated by semi-quantitative real time PCR, a promising one was Selenoprotein T (SELENOT). For functional analyses, an expression vector for SELENOT was generated. To study the effect of SELENOT expression on LPS-induced EC activation and apoptosis, the SELENOT vector was transfected in EC. Immunostaining showed that SELENOT was expressed and localized in the ER. EC transfected with the SELENOT plasmid showed no activation and reduced apoptosis induced by LPS. SELENOT as well as APEX1(1-20) can protect EC against activation and apoptosis and could provide new therapeutic approaches in the treatment of sepsis.

Effect of Different Bone Grafting Materials and Mesenchymal Stem Cells on Bone Regeneration: A Micro-Computed Tomography and Histomorphometric Study in a Rabbit Calvarial Defect Model

This study evaluated the new bone formation potential of micro–macro biphasic calcium phosphate (MBCP) and Bio-Oss grafting materials with and without dental pulp-derived mesenchymal stem cells (DPSCs) and bone marrow-derived mesenchymal stem cells (BMSCs) in a rabbit calvarial bone defect model. The surface structure of the grafting materials was evaluated using a scanning electron microscope (SEM). The multipotent differentiation characteristics of the DPSCs and BMSCs were assessed. Four circular bone defects were created in the calvarium of 24 rabbits and randomly allocated to eight experimental groups: empty control, MBCP, MBCP+DPSCs, MBCP+BMSCs, Bio-Oss+DPSCs, Bio-Oss+BMSCs, and autogenous bone. A three-dimensional analysis of the new bone formation was performed using micro-computed tomography (micro-CT) and a histological study after 2, 4, and 8 weeks of healing. Homogenously porous structures were observed in both grafting materials. The BMSCs revealed higher osteogenic differentiation capacities, whereas the DPSCs exhibited higher colony-forming units. The micro-CT and histological analysis findings for the new bone formation were consistent. In general, the empty control showed the lowest bone regeneration capacity throughout the experimental period. By contrast, the percentage of new bone formation was the highest in the autogenous bone group after 2 (39.4% ± 4.7%) and 4 weeks (49.7% ± 1.5%) of healing (p < 0.05). MBCP and Bio-Oss could provide osteoconductive support and prevent the collapse of the defect space for new bone formation. In addition, more osteoblastic cells lining the surface of the newly formed bone and bone grafting materials were observed after incorporating the DPSCs and BMSCs. After 8 weeks of healing, the autogenous bone group (54.9% ± 6.1%) showed a higher percentage of new bone formation than the empty control (35.3% ± 0.5%), MBCP (38.3% ± 6.0%), MBCP+DPSC (39.8% ± 5.7%), Bio-Oss (41.3% ± 3.5%), and Bio-Oss+DPSC (42.1% ± 2.7%) groups. Nevertheless, the percentage of new bone formation did not significantly differ between the MBCP+BMSC (47.2% ± 8.3%) and Bio-Oss+BMSC (51.2% ± 9.9%) groups and the autogenous bone group. Our study results demonstrated that autogenous bone is the gold standard. Both the DPSCs and BMSCs enhanced the osteoconductive capacities of MBCP and Bio-Oss. In addition, the efficiency of the BMSCs combined with MBCP and Bio-Oss was comparable to that of the autogenous bone after 8 weeks of healing. These findings provide effective strategies for the improvement of biomaterials and MSC-based bone tissue regeneration.

A Novel Strategy to Enhance Microfracture Treatment With Stromal Cell-Derived Factor-1 in a Rat Model

BackgroundMicrofracture is one of the most widely used techniques for the repair of articular cartilage. However, microfracture often results in filling of the chondral defect with fibrocartilage, which exhibits poor durability and sub-optimal mechanical properties. Stromal cell-derived factor-1 (SDF-1) is a potent chemoattractant for mesenchymal stem cells (MSCs) and is expressed at high levels in bone marrow adjacent to developing cartilage during endochondral bone formation. Integrating SDF-1 into an implantable collagen scaffold may provide a chondro-conductive and chondro-inductive milieu via chemotaxis of MSCs and promotion of chondrogenic differentiation, facilitating more robust hyaline cartilage formation following microfracture.ObjectiveThis work aimed to confirm the chemoattractive properties of SDF-1 in vitro and develop a one-step method for incorporating SDF-1 in vivo to enhance cartilage repair using a rat osteochondral defect model.MethodsBone marrow-derived MSCs (BMSCs) were harvested from the femurs of Sprague–Dawley rats and cultured in low-glucose Dulbecco’s modified Eagle’s medium containing 10% fetal bovine serum, with the medium changed every 3 days. Passage 1 MSCs were analyzed by flow cytometry with an S3 Cell Sorter (Bio-Rad). In vitro cell migration assays were performed on MSCs by labeling cells with carboxyfluorescein diacetate, succinimidyl ester (CFDA-SE; Bio-Rad). For the microfracture model, a 1.6-mm-diameter osteochondral defect was created in the femoral trochleae of 20 Sprague–Dawley rats bilaterally until bone marrow spillage was seen under saline irrigation. One knee was chosen at random to receive implantation of the scaffold, and the contralateral knee was left unfilled as an empty control. Type I collagen scaffolds (Kensey Nash) were coated with either gelatin only or gelatin and SDF-1 using a dip coating process. The rats received implantation of either a gelatin-only scaffold (N = 10) or gelatin-and-SDF-1 scaffold (N = 10) at the site of the microfracture. Femurs were collected for histological analyses at 4- and 8-week time points post-operatively, and sections were stained with Safranin O/Fast Green. The samples were graded blindly by two observers using the Modified O’Driscoll score, a validated scoring system for chondral repair. A minimum of 10 separate grading scores were made per sample and averaged. Quantitative comparisons of cell migration in vitro were performed with one-way ANOVA. Cartilage repair in vivo was also compared among groups with one-way ANOVA, and the results were presented as mean ± standard deviation, with P-values &lt; 0.05 considered as statistically significant.ResultsMSC migration showed a dose–response relationship with SDF-1, with an optimal dosage for chemotaxis between 10 and 100 ng/ml. After scaffold implantation, the SDF-1-treated group demonstrated complete filling of the cartilage defect with mature cartilage tissue, exhibiting strong proteoglycan content, smooth borders, and good incorporation into marginal cartilage. Modified O’Driscoll scores after 8 weeks showed a significant improvement of cartilage repair in the SDF-1 group relative to the empty control group (P &lt; 0.01), with a trend toward improvement when compared with the gelatin-only-scaffold group (P &lt; 0.1). No significant differences in scores were found between the empty defect group and gelatin-only group.ConclusionIn this study, we demonstrated a simple method for improving the quality of cartilage defect repair in a rat model of microfracture. We confirmed the chemotactic properties of SDF-1 on rat MSCs and found an optimized dosage range for chemotaxis between 10 and 100 ng/ml. Furthermore, we demonstrated a strategy to incorporate SDF-1 into gelatin–collagen I scaffolds in vivo at the site of an osteochondral defect. SDF-1-treated defects displayed robust hyaline cartilage resurfacing of the defect with minimal fibrous tissue, in contrast to the empty control group. The results of the in vitro and in vivo studies together suggest that SDF-1-mediated signaling may significantly improve the quality of cartilage regeneration in an osteochondral defect.

Comparing the Osteogenic Potentials and Bone Regeneration Capacities of Bone Marrow and Dental Pulp Mesenchymal Stem Cells in a Rabbit Calvarial Bone Defect Model

The bone regeneration efficiency of bone marrow mesenchymal stem cells (BMSCs) and dental pulp mesenchymal stem cells (DPSCs) combined with xenografts in the craniofacial region remains unclear. Accordingly, this study commenced by comparing the cell morphology, cell proliferation, trilineage differentiation, mineral synthesis, and osteogenic gene expression of BMSCs and DPSCs in vitro. Four experimental groups (empty control, Bio-Oss only, Bio-Oss+BMSCs, and Bio-Oss+DPSCs) were then designed and implanted in rabbit calvarial defects. The BMSCs and DPSCs showed a similar morphology, proliferative ability, surface marker profile, and trilineage-differentiation potential in vitro. However, the BMSCs exhibited a higher mineral deposition and expression levels of osteogenic marker genes, including alkaline phosphatase (ALP), runt related transcription factor 2 (RUNX2), and osteocalcin (OCN). In the in vivo studies, the bone volume density in both MSC groups was significantly greater than that in the empty control or Bio-Oss only group. Moreover, the new bone formation and Collagen I / osteoprotegerin protein expressions of the scaffold+MSC groups were higher than those of the Bio-Oss only group. Finally, the Bio-Oss+BMSC and Bio-Oss+DPSC groups had a similar bone mineral density, new bone formation, and osteogenesis-related protein expression. Overall, the DPSCs seeded on Bio-Oss matched the bone regeneration efficacy of BMSCs in vivo and hence appear to be a promising strategy for craniofacial defect repair in future clinical applications.

Cytotoxicity, Biocompatibility and Biomineralization of a New Ready-for-Use Bioceramic Repair Material

New mineral trioxide aggregate (MTA) formulations are constantly introduced in the market, usually in a powder-and-liquid form. Bioceramic (Bio-C) Repair is a ready-for-use material suggested as substitute for MTA, but its properties need to be studied. This study evaluated the cytotoxicity, biocompatibility and biomineralization of Bio-C Repair compared to MTA Repair High-Plasticity (MTA-HP) and white MTA-Angelus (MTA-Ang). L929 fibroblasts were exposed to material-extracted (undiluted, ½ and ¼ dilutions; 6, 24 and 48h). Polyethylene tubes with material or empty (control) were implanted in the subcutaneous tissue of rats. After 7 and 30 days (n=8), the specimens were removed for analysis (hematoxylin-eosin, von Kossa and polarized light). Cytotoxicity data were statistically analyzed by two-way ANOVA, and biocompatibility data by Kruskal-Wallis and Dunn tests (p<0.05). The cells exposed to the materials had greater viability at most of the periods compared with control (p<0.05). The undiluted and ½ dilutions of MTA-HP extract showed higher cytocompatibility than Bio-C Repair at 6 h and with the ¼ dilution at 24 h (p<0.05); the white MTA-Ang showed higher cytocompatibility than Bio-C Repair at most of periods (p<0.05). The undiluted white MTA-Ang extract had higher cytocompatibility at 6 and 24h than MTA-HP, and with ½ dilution at 24h (p<0.05). The materials’ cytocompatibility was similar at 48h for most dilutions (p>0.05). At 7 and 30 days, the groups had moderate and mild inflammation, respectively (p>0.05). All materials showed positive structures for von Kossa and polarized light. In conclusion, Bio-C Repair had similar cytocompatibility to MTA-based materials is biocompatible and induces biomineralization.

Benthic boom: Understanding larval insect colonization in Moorea, French Polynesia

Insects are important in assessing ecosystem quality and health. Current climate change models predict that in the next one hundred years, intense storms separated by long periods of drought will frequent French Polynesia. Variation in water availability may be difficult for many stream insects to cope with. Studying insect response after a disturbance as well as assessing their current distribution and abundance can help us understand greater ecological interactions and allow us to make predictions about future assemblages. The recolonization rate and habitat preference of Simuliidae and Chironomidae larvae were measured in a high elevation stream on Moorea, French Polynesia. Insect recolonization was measured 1, 3, and 6 days after an artificial disturbance event, and habitat preference was determined through the use of 3 introduced substrates: streamside moss, synthetic moss, and an empty control. Habitat preference was also evaluated through the comparison of larval densities across both experiments. Ultimately both Simuliidae and Chironomidae larvae were shown to return to baseline abundance 3 days after a disturbance event. Furthermore, chironomids preferred the synthetic moss substrate to all other habitats, while simuliids preferred the empty control compared to the moss treatment. This likely indicates that the chironomids live within the submerged moss while simuliids live on a rocky substrate. It also suggests that both species can live in a variety of environments and can adapt well to changing conditions.

Benthic boom: Understanding larval insect colonization in Moorea, French Polynesia

Insects are important in assessing ecosystem quality and health. Current climate change models predict that in the next one hundred years, intense storms separated by long periods of drought will frequent French Polynesia. Variation in water availability may be difficult for many stream insects to cope with. Studying insect response after a disturbance as well as assessing their current distribution and abundance can help us understand greater ecological interactions and allow us to make predictions about future assemblages. The recolonization rate and habitat preference of Simuliidae and Chironomidae larvae were measured in a high elevation stream on Moorea, French Polynesia. Insect recolonization was measured 1, 3, and 6 days after an artificial disturbance event, and habitat preference was determined through the use of 3 introduced substrates: streamside moss, synthetic moss, and an empty control. Habitat preference was also evaluated through the comparison of larval densities across both experiments. Ultimately both Simuliidae and Chironomidae larvae were shown to return to baseline abundance 3 days after a disturbance event. Furthermore, chironomids preferred the synthetic moss substrate to all other habitats, while simuliids preferred the empty control compared to the moss treatment. This likely indicates that the chironomids live within the submerged moss while simuliids live on a rocky substrate. It also suggests that both species can live in a variety of environments and can adapt well to changing conditions.

Randomized clinical trial of the effect of simo decoction plus acupuncture and chewing gum on postoperative ileus in patients with hepatocellular carcinoma after hepatic resection.

307 Background: Postoperative ileus (POI) is a common complication following hepatic resection that delays recovery of bowel function and increases length of hospital stay. Simo decoction (SMD) and acupuncture tsusanli acupoint are used to enhance bowel hypomotility in China. Chewing gum reducing POI is reported. The aim of study is to evaluate the effect of SMD plus acupuncture tsusanli acupoint and chewing gum alone on POI and length of hospital stay in patients with hepatocellular carcinoma (HCC) after hepatic resection. Methods: Primary HCC patients undergoing hepatic resection were randomized to SMD plus acupuncture, chewing gum, or empty control group. Interventions were started on postoperative day 1 for six consecutive days or until flatus. Primary endpoints were POI and length of hospital stay. Secondary endpoints were surgical complications. Results: Between March 2015 and August 2015, 162 patients were randomized to SMD plus acupuncture (55), chewing gum (53), or empty control (54). SMD plus acupuncture or chewing gum group have significantly shorter first peristalsis, flatus, and defaecation time than empty control group (all P< 0.05). The mean (s.d.) length of hospital stay of the three groups was 14.0 (4.9), 14.7 (6.2), and 16.5 (6.8) days. The difference between SMD plus acupuncture and empty control group was significant (P = 0.014). However, chewing gum cannot significantly shorten hospital stay than empty control (P = 0.147). Interventions groups had less grade I and II complications. Conclusions: SMD plus acupuncture or chewing gum is a safe treatment to reduce POI and shorten hospital stay. Registration number: NCT02438436 (https://clinicaltrials.gov). Clinical trial information: NCT02438436.

Familiarity affects social network structure and discovery of prey patch locations in foraging stickleback shoals

Numerous factors affect the fine-scale social structure of animal groups, but it is unclear how important such factors are in determining how individuals encounter resources. Familiarity affects shoal choice and structure in many social fishes. Here, we show that familiarity between shoal members of sticklebacks ( Gasterosteus aculeatus ) affects both fine-scale social organization and the discovery of resources. Social network analysis revealed that sticklebacks remained closer to familiar than to unfamiliar individuals within the same shoal. Network-based diffusion analysis revealed that there was a strong untransmitted social effect on patch discovery, with individuals tending to discover a task sooner if a familiar individual from their group had previously done so than if an unfamiliar fish had done so. However, in contrast to the effect of familiarity, the frequency with which individuals had previously associated with one another had no effect upon the likelihood of prey patch discovery. This may have been due to the influence of fish on one another's movements; the effect of familiarity on discovery of an empty ‘control’ patch was as strong as for discovery of an actual prey patch. Our results demonstrate that factors affecting fine-scale social interactions can also influence how individuals encounter and exploit resources.