Bone morphogenetic protein (BMPs) has been so far regarded as one of the highly potent osteoinductive growth factors. Recombinant human bone morphogenetic proteins have been utilized extensively in the disciplines of orthopedics, stomatology, etc. For clinical application, BMPs are usually loaded in carriers with a controlled-release system, to maintain concentration to induce de novo bone formation at the desired site. In this article, the research advancements of the carriers and release systems of BMP are reviewed.
Objective
To investigate the ability of gene-loaded lipopolysaccharide-amine nanopolymersomes (LNPs) in inducing osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by in vitro gene transfection, where LNPs were used as a non-viral cationic carrier, and their properties were optimized during synthesis.
Methods
LNPs were synthesized by a graft-copolymerization method, and the effects of different pH environments during synthesis on physicochemical properties of LNPs and LNPs/plasmid of bone morphogenetic protein 2-green fluorescent protein (pBMP-2-GFP) complexes were explored. Then, optimized LNPs with maximum transfection efficiency and safe cytotoxicity in rat BMSCs were identified by cytotoxicity and transfection experiments in vitro. Thereafter, the optimized LNPs were used to mediate pBMP-2-GFP to transfect rat BMSCs, and the influences of LNPs/pBMP-2-GFP on osteogenic differentiation of BMSCs were evaluated by monitoring the cell morphology, concentration of BMP-2 protein, activity of alkaline phosphatase (ALP), and the formation of calcium nodules.
Results
The nitrogen content, particle size, and zeta potential of LNPs synthesized at pH 8.5 were lower than those of the other pH groups, with the lowest cytotoxicity (96.5%±1.4%) and the highest transfection efficiency (98.8%±0.1%). After transfection treatment, within the first 4 days, BMSCs treated by LNPs/pBMP-2-GFP expressed BMP-2 protein significantly higher than that treated by Lipofectamine2000 (Lipo)/pBMP-2-GFP, polyethylenimine 25K/pBMP-2-GFP, and the blank (non-treated). At 14 days after transfection, ALP activity in BMSCs treated by LNPs/pBMP-2-GFP was higher than that treated by Lipo/pBMP-2-GFP and the blank, comparable to that induced by osteogenic medium; with alizarin red staining, visible calcium nodules were found in BMSCs treated by LNPs/pBMP-2-GFP or osteogenic medium, but absent in BMSCs treated by Lipo/pBMP-2-GFP or the blank with apoptosis. At 21 days after transfection, transparent massive nodules were discovered in BMSCs treated by LNPs/pBMP-2-GFP, and BMSCs exhibited the morphologic features of osteoblasts.
Conclusion
LNPs synthesized at pH 8.5 has optimal transfection efficiency and cytotoxicity, they can efficiently mediate pBMP-2-GFP to transfect BMSCs, and successfully induce their directional osteogenic differentiation, whose inducing effect is comparable to the osteogenic medium. The results suggest that gene transfection mediated by LNPs may be a convenient and effective strategy in inducing directional differentiation of stem cells.
Objective To evaluate the characterization, biocompatibil ity in vitro and in vivo, and antimicrobial activity of an injectable vancomycin-loaded borate glass/chitosan composite (VBC) so as to lay the foundation for its further cl inical application. Methods The sol id phase of VBC was constituted by borate glass and vancomycin, liquid phase was a mixture of chitosan, citric acid, and glucose with the proportion of 1 ∶ 10 ∶ 20. Solid phase and liquid phase was mixed withthe ratio of 2 ∶ 1. Vancomycin-loaded calcium sulfate (VCS) was produced by the same method using calcium sulfate instead of borate glass and sal ine instead of chitosan, as control. High performance liquid chromatography was applied to detect the release rate of antibiotics from VBC and VCS, and minimum inhibitory concentration (MIC) was tested by using an antibiotic tube dilution method. The structure of the VBC and VCS specimens before and 2, 4, 8, 16, and 40 days after immersion in D-Hank’s was examined by scanning electron microscopy, and the phase composition of VBC was analysed by X-ray diffraction after soaked for 40 days. Thirty-three healthy adult New Zealand white rabbits (weighing, 2.25-3.10 kg; male or female) were used to establ ish the osteomyel itis models according to Norden method. After 4 weeks, the models of osteomyel itis were successfully established in 28 rabbits, and they were randomly divided into 4 groups (groups A, B, C, and D). In group A (n=8), simple debridement was performed; in groups B and C (n=8), defect was treated by injecting VCS or VBC after debridement; and in group D (n=4), no treatment was given. The effectiveness of treatment was assessed using radiological and histological techniques after 2 months. Results The releases of vancomycin from VBC lasted for 30 days; the release rate of vancomycin reached 75% at the first 8 days, then could reached more than 90%. The releases of vancomycin from VCS lasted only for 16 days. The MIC of VBC and VCS were both 2 μg/mL. The VCS had a smooth glass crystal surface before immersion, however, it was almost degradated after 4 days. The fairly smooth surface of the VBC pellet became more porous and rougher with time, X-ray diffraction analysis of VBC soaked for 40 days indicated that the borate glass had gradually converted to hydroxyapatite. After 2 months, the best result of treatment was observed in group C, osteomyelitis symptoms disappeared. The X-ray scores of groups A, B, C, and D were 3.50 ± 0.63, 2.29 ± 0.39, 2.00 ± 0.41, and 4.25 ± 0.64, respectively; Smeltzer scores were 6.00 ± 0.89, 4.00 ± 0.82, 3.57 ± 0.98, and 7.25 ± 0.50, respectively. The scores were significantly higher in group D than in groups A, B, and C (P lt; 0.05), and in group A than in groups B and C (P lt; 0.05). The scores were higher in group B than in group C, but no significant difference was found (P gt; 0.05). Conclusion The VBC is effective in treating chronic osteomyelitis of rabbit by providing a sustained release of vancomycin, in addition to stimulating bone regeneration, so it may be a promising biomaterial for treating chronic osteomyelitis.
ObjectiveTo summarize the possible roles and relevant mechanisms of solute carrier family 3 member A2 (SLC3A2) gene in hepatocellular carcinoma (HCC), and explore its clinical application prospects and value in the diagnosis, treatment, and prognosis of patients with HCC. MethodThe literature on reseaches of the SLC3A2 gene and its association with HCC both domestically and internationally in recent years was reviewed and summarized. ResultsNotably, the SLC3A2 exhibited obviously elevated expression in the HCC tissue as compared with the normal liver tissue. It mainly affected the disease progression of HCC by regulating the intracellular and extracellular amino acids transport, inhibiting the ferroptosis of cells, activating the mechanistic target of rapamycin complex signaling pathways and integrin signaling pathway, and played an important role in the diagnosis, treatment, and prognosis of patients with HCC. ConclusionFrom the results of literature review collected, SLC3A2 might be closely associated with the migration, invasion, proliferation, and apoptosis of HCC cell, and it is expected to serve as an indicator for evaluating survival and prognosis of patients with HCC, and become one of the effective treatment targets for HCC in future.
Objective To investigate the growth, expansion, and metabolic characteristics of the human dermal fibroblasts cultured in a bioreactor with batch and medium exchange modes. Methods Human dermal fibroblasts separated from foreskin were seeded into a 1.5 liter CelliGen bioreactor with 5mg/ml of microcarriers. The cell growth, glucose consumption and lactate accumulation in both batch and medium exchange cultures were measured. Results The growth density of fibroblasts cultured in the bioreactor with medium-exchange mode reached 2.08×106 cell/ml, expande 29.7 folds, which was 1.81 times as high as that in batch culture. By comparison with the results obtained in T-flasks and spinners under the same medium-exchange conditions, the cell density in the bioreactor was 9.16 and 1.43 times as high as those in T-flasks and spinners respectively owing to that the limitation effect the attachment surface, nutrient exhaust, and by-product accumulation on the growth of fibroblasts in the bioreactor by using microcarriers, medium-exchange, as well as gas aeration was elimnated. Conclution The above results indicate that suspended cultures with microcarriers in bioreactors are an effective approach to rpovide large amounts of seeding cells for tissue engineering.
ObjectiveTo observe intervention effect of Shenlingcao oral liquid on asymptomatic chronic hepatitis B virus carriers (AsC).
MethodsA self control before-after trial was conducted in the First Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine and the Ninth People's Hospital of Nanchang City from November 2011 to May 2012. A total of 64 AsCs were treated by Shenlingcao oral liquid (1 bottle/d, 200 mL, once daily for 6 months). Serum HBV viral load, six specific serum markers of HBV and 11 liver function index were tested and recorded before and at the 1th, 3th, 6th months of the treatment. Analysis of variance of repeated data was conducted.
ResultsAfter one month of the treatment, 35/57 (61.40%) AsCs' serum HBV-DNA loads decreased, 1 log decrease was observed in 15 cases, 2 log decrease was observed in 4 cases, and decrease under the detection limit was observed in 12 cases. 41/57 (71.93%) AsCs' serum HBV-DNA loads decreased after 3 months of treatment, 1 log decrease was observed in 21 cases, 2 log decrease was observed in 5 cases, and decrease under the detection limit was observed in 15 cases. 31/49 (63.26%) AsCs' serum HBV-DNA loads decreased after 6 months of the treatment, 1 log decrease was observed in 19 cases, decrease more than 2 log was observed in 7 cases, and decrease under the detection limit was observed in 12 cases. The serum HBV viral loads at different time points of the treatment were significantly different (P<0.001). As medication time went, AsCs' serum HBV viral loads presented a decrease trend after taking Shenlingcao oral liquid, especially obvious at the 3th month.
ConclusionShenlingcao oral liquid could help promote AsCs' ability of clearing virus and controlling serum HBVDNA loads.
Objective To introduce an injectable andin situ gelling gelatin hydrogel, and to explore the possibility as a carrier for demineralized bone matrix (DBM) powder delivery. Methods First, thiolated gelatin was prepared and the thiol content was determined by Ellman method, and then the injectable andin situ gelling gelatin hydrogel (Gel) was formed by crosslinking of the thiolated gelatin and poly (ethylene oxide) diacrylate and the gelation time was determined by inverted method. Finally, the DBM-Gel composite was prepared by mixing Gel and DBM powder. The cytotoxicity was tested by live/dead staining and Alamar blue assay of the encapsulated cells in the DBM-Gel. Forin vitro cell induction, C2C12 cells were firstly incubated onto the surface of the DBM and then the composite was prepared. The experiment included two groups: DBM-Gel and DBM. The alkaline phosphatase (ALP) activity was determined at 1, 3, 5,and 7 days after culture.In vivo osteoinductivity was evaluated using ectopic bone formation model of nude rats. Histological observation and the ALP activity was measured in DBM-Gel and DBM groups at 4 weeks after implantation. Results The thiol content in the thiolated gelatin was (0.51±0.03) mmol/g determined by Ellman method. The gelation time of the hydrogel was (6±1) minutes. DBM powder can be mixed with the hydrogel and injected into the implantation site within the gelation time. The cells in the DBM-Gel exhibited spreading morphology and connected each other in part with increasing culture time. The viability of the cells was 95.4%±1.9%, 97.3%±1.3%, and 96.1%±1.6% at 1, 3, and 7 days after culture, respectively. The relative proliferation was 1.0±0.0, 1.1±0.1, 1.5±0.1, and 1.6±0.1 at 1, 3, 5, and 7 days after culture respectively.In vitro induction showed that the ALP activity of the DBM-Gel group was similar to that of the DBM group, showing no significant difference (P>0.05). With increasing culture time, the ALP activities in both groups increased gradually and the activity at 5 and 7 days was significantly higher than that at 1 and 3 days (P<0.05), while there was no significant difference between at 1 and 3 days, and between 5 and 7 days (P>0.05). At 4 weeks after implantationin vivo, new bone and cartilage were observed, but no bone marrow formation in DBM-Gel group; in DBM group, new bone, new cartilage, and bone marrow formation were observed. The histological osteoinduction scores of DBM-Gel and DBM groups were 4.0 and 4.5, respectively. The ALP activities of DBM-Gel and DBM groups were respectively (119.4±22.7) and (146.7±13.0) μmol/mg protein/min, showing no significant difference (t=–2.085,P=0.082). Conclusion The injectable andin situ gelling gelatin hydrogel for delivery of DBM is feasible.
As one of the traditional computer simulation techniques, molecular simulation can intuitively display and quantify molecular structure and explain experimental phenomena from the microscopic molecular level. When the simulation system increases, the amount of calculation will also increase, which will cause a great burden on the simulation system. Coarse-grained molecular dynamics is a method of mesoscopic molecular simulation, which can simplify the molecular structure and improve computational efficiency, as a result, coarse-grained molecular dynamics is often used when simulating macromolecular systems such as drug carrier materials. In this article, we reviewed the recent research results of using coarse-grained molecular dynamics to simulate drug carriers, in order to provide a reference for future pharmaceutical preparation research and accelerate the entry of drug research into the era of precision drug design.
For a long period of time, silk fibroin has been applied in biomedical areas. Along with the development of biotechnology, new functions of silk fibroin are being found and developed. From the suture of surgery to the therapeutic drug and the ordinary tissue engineering frame to high grade frame with drug buffer system, exploitation of silk fibroin is constantly introduced with something new from the old ones. In our review, we summarize the applications of silk fibroin in tissue engineering, drug buffer system and medical care.
Objective To review the progress and clinical application of malleable bone paste/putty. MethodsRecent literature about malleable bone paste/putty was reviewed and analyzed. ResultsThe preparation and clinical application of malleable bone paste/putty have become increasingly mature. Many kinds of malleable bone paste/putty have been applied extensively and the good clinical results have been achieved in the treatment of the irregular bone defects. The materials and methods for preparing malleable bone paste/putty are different. Then they have different bone repair abilities. ConclusionMalleable bone paste/putty provides effective method to treat irregular bone defects. But the malleable bone paste/putty still has some shortage, so further researches should be carried out.
