Mexenone protects mice from LPS-induced sepsis by EC barrier stabilization.

Blood vessels permit the selective passage of molecules and immune cells between tissues and circulation. Uncontrolled inflammatory responses from an infection can increase vascular permeability and edema, which can occasionally lead to fatal organ failure. We identified mexenone as a vascular permeability blocker by testing 2,910 compounds in the Clinically Applied Compound Library using the lipopolysaccharide (LPS)-induced vascular permeability assay. Mexenone suppressed the LPS-induced downregulation of junctional proteins and phosphorylation of VE-cadherin in Bovine Aortic Endothelial Cells (BAECs). The injection of mexenone 1 hr before LPS administration completely blocked LPS-induced lung vascular permeability and acute lung injury in mice after 18hr. Our results suggest that mexenone-induced endothelial cell (EC) barrier stabilization could be effective in treating sepsis patients.

Assessment of Esophageal Reconstruction via Bioreactor Cultivation of a Synthetic Scaffold in a Canine Model.

OBJECTIVES: Using tissue-engineered materials for esophageal reconstruction is a technically challenging task in animals that requires bioreactor training to enhance cellular reactivity. There have been many attempts at esophageal tissue engineering, but the success rate has been limited due to difficulty in initial epithelialization in the special environment of peristalsis. The purpose of this study was to evaluate the potential of an artificial esophagus that can enhance the regeneration of esophageal mucosa and muscle through the optimal combination of a double-layered polymeric scaffold and a custom-designed mesenchymal stem cell-based bioreactor system in a canine model. METHODS: We fabricated a novel double-layered scaffold as a tissue-engineered esophagus using an electrospinning technique. Prior to transplantation, human-derived mesenchymal stem cells were seeded into the lumen of the scaffold, and bioreactor cultivation was performed to enhance cellular reactivity. After 3 days of cultivation using the bioreactor system, tissue-engineered artificial esophagus was transplanted into a partial esophageal defect (5×3 cm-long resection) in a canine model. RESULTS: Scanning electron microscopy (SEM) showed that the electrospun fibers in a tubular scaffold were randomly and circumferentially located toward the inner and outer surfaces. Complete recovery of the esophageal mucosa was confirmed by endoscopic analysis and SEM. Esophagogastroduodenoscopy and computed tomography also showed that there were no signs of leakage or stricture and that there was a normal lumen with complete epithelialization. Significant regeneration of the mucosal layer was observed by keratin-5 immunostaining. Alpha-smooth muscle actin immunostaining showed significantly greater esophageal muscle regeneration at 12 months than at 6 months. CONCLUSION: Custom-designed bioreactor cultured electrospun polyurethane scaffolds can be a promising approach for esophageal tissue engineering.

Shinjulactone A Blocks Vascular Inflammation and the Endothelial-Mesenchymal Transition.

Objective: The endothelial inflammatory response plays an important role in atherogenesis by inducing nuclear factor (NF)κB-dependent cell adhesion molecule expression and monocyte recruitment. Here, we screened for natural ligands and investigated the ability of shinjulactone A to inhibit interleukin-1ß (IL-1ß)-induced endothelial inflammatory signaling. Methods: The natural compound library included 880 single compounds isolated from medicinal plants by the Korean Medicinal Material Bank. Primary endothelial cells were pretreated with single compounds before stimulation with IL-1ß to induce endothelial inflammation. Endothelial inflammation was measured by assaying NFκB activation and monocyte adhesion. The endothelial-mesenchymal transition (EndMT) was evaluated using cell type-specific marker protein expression and morphology. Results: Shinjulactone A was identified as an efficient blocker of IL-1ß -induced NFκB activation, with a half-maximal inhibitory concentration of approximately 1 µM, and monocyte recruitment in endothelial cells. However, it did not affect lipopolysaccharide-induced NFκB activation in macrophages. Compared to Bay 11-782, a well-known NFκB inhibitor that shows considerable cytotoxicity during long-term treatment, shinjulactone A did not affect endothelial cell viability. Furthermore, it also significantly inhibited the EndMT, which is known to promote atherosclerosis and plaque instability. Conclusion: We suggest that shinjulactone A may be an effective and safe drug candidate for atherosclerosis because it targets and inhibits both endothelial inflammation and the EndMT, without impairing NFκB-dependent innate immunity in macrophages.

Alternative non-oral nutrition in a rat model: a novel modified gastrostomy technique.

The gastrostomy technique is essential for esophageal reconstruction using a scaffold. To date, there are no established methods to supply nutrients through a gastrostomy tube in rats. The purpose of this study was to analyze the feasibility of a newly modified gastrostomy technique for non-oral nutrition in an adult rat model. We modified the gastrostomy technique for adult rats in a few different ways. (1) The external opening for food injection was made at the midpoint between the ears to prevent damage due to self-harm behaviour. (2) An imbedded subcutaneous tunnel was created between the internal and external openings of the gastrostomy. We compared the efficacy and safety between groups with a T-tube for biliary drainage (TT group, n=14) and a conventional silicone Foley catheter (FC group, n=7) as optimal gastrostomy tubes for in a rat model. We also evaluated the feasibility of the heparin cap connector at the end of gastrostomy tube to control food supply in the TT group (with a cap, n=7; without a cap, n=7). No mortality was observed in the TT group with a cap, whereas most rats in the FC group died within 2 weeks after the procedure. Weight loss decreased significantly in the TT group with a cap compared with all the other groups. The appearance and attitude scores were significantly better in the TT group with a cap. In addition, histologic analysis showed that the TT group a cap showed a marked decrease over time in tissue fibrosis and macrophages compared with the other experimental groups. Therefore, gastrostomy using a silicone T-tube plugged with a cap proved to be a stable and effective option for non-oral feeding in an adult rat model.

Combined Application of Prototype Ultrasound and BSA-Loaded PLGA Particles for Protein Delivery.

PURPOSE: To develop an in vitro culture system for tissue engineering to mimic the in vivo environment and evaluate the applicability of ultrasound and PLGA particle system. METHODS: For tissue engineering, large molecules such as growth factors for cell differentiation should be supplied in a controlled manner into the culture system, and the in vivo microenvironment need to be reproduced in the system for the regulation of cellular function. In this study, portable prototype ultrasound with low intensity was devised and tested for protein release from bovine serum albumin (BSA)-loaded poly(lactic-co-glycolic acid) (PLGA) particles. RESULTS: BSA-loaded PLGA particles were prepared using various types of PLGA reagents and their physicochemical properties were characterized including particle size, shape, or aqueous wetting profiles. The BSA-loaded formulation showed nano-ranged size distribution with optimal physical stability during storage period, and protein release behaviors in a controlled manner. Notably, the application of prototype ultrasound with low intensity influenced protein release patterns in the culture system containing the BSA-loaded PLGA formulation. The results revealed that the portable ultrasound set controlled by the computer could contribute for the protein delivery in the culture medium. CONCLUSIONS: This study suggests that combined application with ultrasound and protein-loaded PLGA encapsulation system could be utilized to improve culture system for tissue engineering or cell regeneration therapy.

Synergistic Effect of Growth Factor Releasing Polymeric Nanoparticles and Ultrasound Stimulation on Osteogenic Differentiation.

Mesenchymal stem cells (MSCs) have been extensively used in the tissue regeneration therapy. Ex vivo therapy with well-differentiated osteogenic cells is known as an efficient treatment for musculoskeletal diseases, including rheumatoid diseases. However, along with its high cost, the current therapy has limitations in terms of restoring bone regeneration procedures. An efficient process for the cell differentiation to obtain a large number of functionalized osteogenic cells is necessary. Therefore, it is strongly recommended to develop strategies to produce sufficient numbers of well-differentiated osteogenic cells from the MSCs. In general, differentiation media with growth factors have been used to facilitate cell differentiation. In the present study, the poly (lactic-co-glycolic acid) (PLGA) nanoparticles incorporating the growth factors were included in the media, resulting in releasing growth factors (dexamethasone and ß-glycerophosphate) in the media in the controlled manner. Stable growth and early differentiation of osteogenic cells were achieved by the PLGA-based growth factor releasing system. Moreover, low intensity pulsed ultrasound was applied to this system to induce cell differentiation process. The results revealed that, as a biomarker at early stage of osteogenic cell differentiation, Lamin A/C nuclear protein was efficiently expressed in the cells growing in the presence of PLGA-based growth factor reservoirs and ultrasound. In conclusion, our results showed that the ultrasound stimulation combined with polymeric nanoparticles releasing growth factors could potentially induce osteogenic cell differentiation.

Experimental investigation of esophageal reconstruction with electrospun polyurethane nanofiber and 3D printing polycaprolactone scaffolds using a rat model.

BACKGROUND: We evaluated the outcome of esophageal reconstructions using tissue-engineered scaffolds. METHOD: Partial esophageal defects were reconstructed with the following scaffolds; animals were grouped (n = 7 per group) as follows: (a) normal rats; (b) rats implanted with three-dimensional printing (3DP) polycaprolactone (PCL) scaffolds; (c) with human adipose-derived mesenchymal stem cell (ADSC)-seeded 3DP PCL scaffolds; (d) with polyurethane (PU)-nanofiber(Nf) scaffolds; and (e) with ADSC-seeded PU-Nf scaffolds. RESULTS: The esophageal defects were successfully repaired; however, muscle regeneration was greater in the 3DP PCL + ADSC groups than in the PU-Nf + ADSC groups (P < .001). Regeneration of the epithelium was greater in PU-Nf and PU-Nf + ADSC groups than in the 3DP PCL and 3DP PCL + ADSC groups (P < .001). CONCLUSION: A tendency for more re-epithelization was observed with the PU-Nf scaffolds, while more muscle regeneration was achieved with the 3DP PCL scaffolds.

Tissue-Engineered Graft for Circumferential Esophageal Reconstruction in Rats.

The use of biocompatible materials for circumferential esophageal reconstruction is a technically challenging task in rats and requires an optimal implant technique with nutritional support. Recently, there have been many attempts at esophageal tissue engineering, but the success rate has been limited due to difficulty in early epithelization in the special environment of peristalsis. Here, we developed an artificial esophagus that can improve the regeneration of the esophageal mucosa and muscle layers through a two-layered tubular scaffold, a mesenchymal stem cell-based bioreactor system, and a bypass feeding technique with modified gastrostomy. The scaffold is made of polyurethane (PU) nanofibers in a cylindrical shape with a three-dimensional (3D) printed polycaprolactone strand wrapped around the outer wall. Prior to transplantation, human-derived mesenchymal stem cells were seeded into the lumen of the scaffold, and bioreactor cultivation was performed to enhance cellular reactivity. We improved the graft survival rate by applying surgical anastomosis and covering the implanted prosthesis with a thyroid gland flap, followed by temporary nonoral gastrostomy feeding. These grafts were able to recapitulate the findings of initial epithelialization and muscle regeneration around the implanted sites, as demonstrated by histological analysis. In addition, increased elastin fibers and neovascularization were observed in the periphery of the graft. Therefore, this model presents a potential new technique for circumferential esophageal reconstruction.

A Platform for Studying of the Three-Dimensional Migration of Hematopoietic Stem/Progenitor Cells.

BACKGROUND: Hematopoietic stem/progenitor cells (HSPCs) have the property to return to the bone marrow, which is believed to be critical in situations such as HSPC transplantation. This property plays an important role in the stemness, viability, and proliferation of HSPCs, also. However, most in vitro models so far have not sufficiently simulated the complicate environment. Here, we proposed a three-dimensional experimental platform for the quantitative study of the migration of HSPCs. METHODS: After encapsulating osteoblasts (OBs) in alginate beads, we quantified the migration of HSPCs into the beads due to the physical environment using digital image processing. Intermittent hydrostatic pressure (IHP) was used to mimic the mechanical environment of human bone marrow without using any biochemical factors. The expression of stromal cell-derived factor 1 (SDF-1) under IHP was measured. RESULTS: The results showed that the presence of OBs in the hydrogel scaffold initiate the movement of HSPCs. Furthermore, the IHP promotes the migration of HSPCs, even without the addition of any biochemical factors, and the results were confirmed by measuring SDF-1 levels. CONCLUSION: We believe this suggested three-dimensional experimental platform consisting of a simulated in vivo physical environment and encapsulated OBs should contribute to in vitro migration studies used to investigate the effects of other external factors.

Influences of sodium tantalite submicro-particles in polyetheretherketone based composites on behaviors of rBMSCs/HGE-1 cells for dental application.

Dental implanted materials require excellent mechanical properties, biocompatibility as well as integration with bone tissue and gingival tissue to achieve early loading and long-term stability. In this study, cubic shape sodium tantalite (ST) submicro-particles with the size of around 180 nm were synthesized by a hydrothermal method, and ST/polyetheretherketone (PEEK) composites (TPC) with ST content of 20 w% (TPC20) and 40 w% (TPC40) were prepared by melting blend. The results showed that the compressive strength, thermal properties, surface roughness, hydrophilicity and surface energy as well as adsorption of proteins on TPC40 were also significantly enhanced compared with TPC20 and PEEK. Moreover, the responses (adhesion and proliferation as well as differentiation) of rat bone marrow mesenchymal stem cells (rBMSCs), and responses (adhesion, and proliferation) of human gingival epithelial (HGE-1) cells to TPC40 were significantly promoted compared with TPC20 and PEEK. The results demonstrated that ST content in TPC had remarkable effects on the surface properties, which played key roles in stimulating the responses of both rBMSCs and HGE-1 cells. TPC40 with increased surface properties and excellent cytocompatibility might have great potential as an implanted material for dental application.

Mechanical stimuli enhance simultaneous differentiation into oesophageal cell lineages in a double-layered tubular scaffold.

The tissue-engineered oesophagus serves as an alternative and promising therapeutic approach for long-gap oesophageal replacement. This study proposes an advanced in vitro culture platform focused on construction of the oesophagus by combining an electrospun double-layered tubular scaffold, stem cells, biochemical reagents, and biomechanical factors. Human mesenchymal stem cells were seeded onto the inner and outer surfaces of the scaffold. Mechanical stimuli were applied with a hollow organ bioreactor along with different biochemical reagents inside and outside of the scaffold. Electrospun fibres in a tubular scaffold were found to be randomly and circumferentially oriented for the inner and outer surfaces, respectively. Amongst the two types of mechanical stimuli, the intermittent shear flow that can simultaneously cause circumferential stretching due to hydrostatic pressure, and shear stress caused by flow on the inner surface, was found to be more effective for simultaneous differentiation into epithelial and muscle lineage than steady shear flow. Under these conditions, the expression of epithelial markers on the inner surface was significantly observed, although it was minimal on the outer surface. Muscle differentiation showed the opposite expression pattern. Meanwhile, the mechanical tests showed that the strength of the scaffold was improved after incubation for 14 days. We have developed a potential platform for tissue-engineered oesophagus construction. Specifically, simultaneous differentiation into epithelial and muscle lineages can be achieved by utilizing the double-layered scaffold and appropriate mechanical stimulation.

The combined effects of hierarchical scaffolds and mechanical stimuli on ex vivo expansion of haematopoietic stem/progenitor cells.

We describe the ex vivo expansion of haematopoietic stem/progenitor cells (HSPCs) with consideration of their eventual in-vivo niche. We firstly fabricated hierarchically structured scaffolds (lattices derived via three-dimensional plotting combined with electrospun submicron fibers coated with vitronectin to increase cell affinity). We also applied intermittent hydrostatic pressure (IHP) to mimic the physical environment of the in vivo niche. In the absence of mechanical stimuli, the cell phenotype (CD34+, CD34+CD38-) remained excellent in the vitronectin-treated group. Two IHP regimens were tested; optimally, cells were pressurized (20 kPa) for 2 min and then rested for 13 min. On day 7 of culture, the total cell number had increased 21.2-fold and that of CD34+ cells 10.94-fold. CD34+ and CD34+CD38- cells constituted 44.50 and 44.07% of total cells, respectively. Colony-forming counts and the long-term culture-initiating cell assay showed that clonogenic potential was greatly improved under our experimental conditions. Scaffolds with hierarchical structures were valuable in this context. Furthermore, ex vivo expansion of HSPCs was improved by physical stimulation.

Tissue-Engineered Esophagus via Bioreactor Cultivation for Circumferential Esophageal Reconstruction.

The use of biomaterials for circumferential esophageal repair is technically challenging in a rat model, and an optimal scaffold implantation technique with nutritional support is essential. The purpose of this study was to investigate the effects of three-dimensional printed esophageal grafts and bioreactor cultivation on muscle regeneration and reepithelialization from circumferential esophageal defects in a rat model. Here, we designed an artificial esophagus that can enhance the regeneration of esophageal mucosa and muscle through the optimal combination of a two-layered tubular scaffold and mesenchymal stem cell-based bioreactor system. The graft was verified by the performance comparison with an omentum-cultured esophageal scaffold. We also applied a new surgical anastomosis technique and a thyroid gland flap over the implanted scaffold to improve graft survival. Although no regenerated mucosal layer was observed around the implants of the control group, histological examination of the regenerative esophagi along the scaffold revealed that the bioreactor system and omentum-cultured groups showed more than 80% of the mucosal regeneration without a fistula. The regenerated tissues showed that the integration of the esophageal scaffold and its native esophageal tissue was intact and were covered with layers of stratified squamous epithelium with several newly developed blood vessels. Therefore, this study describes a novel approach for circumferential esophageal reconstruction. Impact Statement In vivo functional esophageal reconstruction remains challenging due to anastomosis site leakage and necrosis of the implanted scaffold in a circumferential esophageal defect. Therefore, it is necessary to develop a tissue-engineered esophagus that enables regeneration of esophageal mucosa and muscle without leakage of the esophageal anastomosis. In this study, we proposed an intriguing strategy that combines a mesenchymal stem cell-seeded tubular scaffold with a bioreactor system for esophageal reconstruction and introduced a new surgical anastomosis technique with the thyroid gland flap over the implanted scaffold to improve graft survival. We believe that this system should be a powerful platform for circumferential replacement of the esophagus in a rat model.

Combinational effects of mechanical forces and substrate surface characteristics on esophageal epithelial differentiation.

Even the efficacy of substrate and mechanical stimuli in addition to biochemical cues have been recognized in many studies of stem cell differentiation, few studies have been reported on the differentiation into esophageal epithelial cells. Therefore, the aim of this study was set to propose a method of differentiating stem cells into esophageal epithelial cells according to biochemical reagent concentration, substrate properties, and mechanical forces. After the concentration of all-trans retinoic acid was determined as 5 µM by a baseline experiment, the degree of differentiation was compared in three different kinds of substrates: cover glass, polyurethane (PU) membrane, and electrospun PU sheet (ePU). Then, on the substrate showing the more positive results, that is, ePU, two types of mechanical forces, intermittent hydrostatic pressure (IHP), and shear stress (SS), were applied individually at different magnitudes for the latter 7 days of an overall incubation period of 14 days. Following various biological assays, the lower IHP (50 mmHg) resulted in greater positive effects than the others. Even with cessation of the mechanical force, the relevant markers were remarkably increased. Although the range of factors regulating differentiation was limited, this study nonetheless demonstrated the combinational effects of mechanical force along with substrate type for the first time in related studies. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 552-560, 2019.

Cyclic stretch increases mitochondrial biogenesis in a cardiac cell line.

Unlike stable and immobile cell line conditions, animal hearts contract and relax to pump blood throughout the body. Mitochondria play an essential role by producing biological energy molecules to maintain heart function. In this study, we assessed the effect of heart mimetic cyclic stretch on mitochondria in a cardiac cell line. To mimic the geometric and biomechanical conditions surrounding cells in vivo, cyclic stretching was performed on HL-1 murine cardiomyocytes seeded onto an elastic micropatterned substrate (10% elongation, 0.5 Hz, 4 h/day). Cell viability, semi-quantitative Q-PCR, and western blot analyses were performed in non-stimulated control and cyclic stretch stimulated HL-1 cell lines. Cyclic stretch significantly increased the expression of mitochondria biogenesis-related genes (TUFM, TFAM, ERRα, and PGC1-α) and mitochondria oxidative phosphorylation-related genes (PHB1 and CYTB). Western blot analysis confirmed that cyclic stretch increased protein levels of mitochondria biogenesis-related proteins (TFAM, and ERRα) and oxidative phosphorylation-related proteins (NDUFS1, UQCRC, and PHB1). Consequently, cyclic stretch increased mitochondrial mass and ATP production in treated cells. Our results suggest that cyclic stretch transcriptionally enhanced mitochondria biogenesis and oxidative phosphorylation without detrimental effects in a cultured cardiac cell line.

Synergistic Integration of Mesenchymal Stem Cells and Hydrostatic Pressure in the Expansion and Maintenance of Human Hematopoietic/Progenitor Cells.

Ex vivo expansion of hematopoietic stem/progenitor cell (HSPC) has been investigated to improve the clinical outcome of HSPC transplantation. However, ex vivo expansion of HSPCs still faces a major obstacle in that HPSCs tend to differentiate when proliferating. Here, we cocultured HSPCs with mesenchymal stem cells (MSCs) and divided the HSPCs into two fractions according to whether they came into adherent to MSCs or not. Additionally, we used hydrostatic pressure (HP) to mimic the physical conditions in vivo. Even nonadherent cells expanded to yield a significantly larger number of total nucleated cells (TNCs), adherent cells maintained the HSPC phenotype (CD34+, CD34+CD38-, and CD133+CD38-) to a greater extent than nonadherent cells and had superior clonogenic potential. Moreover, applying HP significantly increased the number of TNCs, the frequency of the immature HSPC phenotype, and the clonogenic potential. Furthermore, the genetic markers for the HSPC niche were significantly increased under HP. Our data suggest that the nonadherent fraction is the predominant site of HSPC expansion, whereas the adherent fraction seems to mimic the HSPC niche for immature cells. Moreover, HP has a synergistic effect on expansion and functional maintenance. This first study utilizing HP has a potential of designing clinically applicable expansion systems.

Enhanced biocompatibility and osteogenic potential of mesoporous magnesium silicate/polycaprolactone/wheat protein composite scaffolds.

BACKGROUND: Successful bone tissue engineering using scaffolds is primarily dependent on the properties of the scaffold, including biocompatibility, highly interconnected porosity, and mechanical integrity. METHODS: In this study, we propose new composite scaffolds consisting of mesoporous magnesium silicate (m_MS), polycaprolactone (PCL), and wheat protein (WP) manufactured by a rapid prototyping technique to provide a micro/macro porous structure. Experimental groups were set based on the component ratio: (1) WP0% (m_MS:PCL:WP =30:70:0 weight per weight; w/w); (2) WP15% (m_MS:PCL:WP =30:55:15 w/w); (3) WP30% (m_MS:PCL:WP =30:40:30 w/w). RESULTS: Evaluation of the properties of fabricated scaffolds indicated that increasing the amount of WP improved the surface hydrophilicity and biodegradability of m_MS/PCL/WP composites, while reducing the mechanical strength. Moreover, experiments were performed to confirm the biocompatibility and osteogenic differentiation of human mesenchymal stem cells (MSCs) according to the component ratio of the scaffold. The results confirmed that the content of WP affects proliferation and osteogenic differentiation of MSCs. Based on the last day of the experiment, ie, the 14th day, the proliferation based on the amount of DNA was the best in the WP30% group, but all of the markers measured by PCR were the most expressed in the WP15% group. CONCLUSION: These results suggest that the m_MS/PCL/WP composite is a promising candidate for use as a scaffold in cell-based bone regeneration.

Influences of mesoporous magnesium calcium silicate on mineralization, degradability, cell responses, curcumin release from macro-mesoporous scaffolds of gliadin based biocomposites.

Macro-mesoporous scaffolds based on wheat gliadin (WG)/mesoporous magnesium calcium silicate (m-MCS) biocomposites (WMC) were developed for bone tissue regeneration. The increasing amount of m-MCS significantly improved the mesoporosity and water absorption of WMC scaffolds while slightly decreased their compressive strength. With the increase of m-MCS content, the degradability of WMC scaffolds was obviously enhanced, and the decrease of pH value could be slow down after soaking in Tris-HCl solution for different time. Moreover, the apatite mineralization ability of the WMC scaffolds in simulated body fluid (SBF) was obviously improved with the increase of m-MCS content, indicating good bioactivity. The macro-mesoporous WMC scaffolds containing m-MCS significantly stimulated attachment, proliferation and differentiation of MC3T3-E1 cells, indicating cytocompatibility. The WMC scaffold containing 40 w% m-MCS (WMC40) possessed the highest porosity (including macroporosity and mesoporosity), which loaded the highest amount of curcumin (CU) as well as displayed the slow release of CU. The results suggested that the incorporation of m-MCS into WG produced biocomposite scaffolds with macro-mesoporosity, which significantly improved water absorption, degradability, bioactivity, cells responses and load/sustained release of curcumin.

Characterization and osteogenic evaluation of mesoporous magnesium-calcium silicate/polycaprolactone/polybutylene succinate composite scaffolds fabricated by rapid prototyping.

The properties of scaffolds for bone tissue engineering, including their biocompatibility, highly interconnected porosity, and mechanical integrity, are critical for promoting cell adhesion, proliferation, and osteoinduction. We used various physical and biological assays to obtain in vitro confirmation that the proposed composite scaffolds are potentially suitable for applications to bone tissue engineering. The proposed new composite scaffolds, which we fabricated by a rapid prototyping technique, were composed of mesoporous magnesium-calcium silicate (m_MCS), polycaprolactone (PCL), and polybutylene succinate (PBSu). We systematically evaluated the characteristics of the composite scaffolds, such as the hydrophilicity and bioactivity. We also investigated the proliferation and osteogenic differentiation of human mesenchymal stem cells (MSCs) scaffolded on the m_MCS/PCL/PBSu composite. Our results showed that, compared to the m_MCS/PCL scaffold, the m_MCS/PCL/PBSu scaffold has improved water absorption, in vitro degradability, biocompatibility, and bioactivity in simulated body fluid, while its mechanical strength is reduced. Moreover, the results of the cytotoxicity tests specified in ISO 10993-12 and ISO 10993-5 clearly indicate that the m_MCS/PCL scaffold is not toxic to cells. In addition, we obtained significant increases in initial cell attachment and improvements to the osteogenic MSC differentiation by replacing the m_MCS/PCL scaffold with the m_MCS/PCL/PBSu scaffold. Our results indicate that the m_MCS/PCL/PBSu scaffold achieves enhanced bioactivity, degradability, cytocompatibility, and osteogenesis. As such, this scaffold is a potentially promising candidate for use in stem cell-based bone tissue engineering.