Macromolecular crowding facilitates rapid fabrication of intact, robust cell sheets.

OBJECTIVES: To develop a rapid and simple method to fabricate intact, robust cell sheets from common cell culture dishes by combination of a macromolecular crowding (MMC) reagent and vitamin C. RESULTS: It was found that 3T3 fibroblasts or human bone marrow mesenchymal stem cells (hBMSCs) and their secreted cell derived extracellular matrices could be easily detached as intact cell sheets under gently pipetting after treated by MMC and vitamin C for 4 days. This method also allowed fabrication of functional multi-layered hepatic cell sheets by culturing 10 × 104 cells/cm2 HepG2 cells on top of confluent 3T3 fibroblast layers. What's more, MMC induced hBMSC cell sheets demonstrated 1.9 times larger area and 1.6 times greater cell number than that of cell sheets harvested from temperature-responsive cell culture dishes. CONCLUSION: MMC based method make it possible to fabricate various types of cell sheets more conveniently, economically, and thus may facilitate wide application of cell sheet technology.

Design of Cyclic Peptide-Based Nanospheres and the Delivery of siRNA.

In recent years, cyclic peptides have attracted much attention due to their chemical and enzymatic stability, low toxicity, and easy modification. In general, the self-assembled nanostructures of cyclic peptides tend to form nanotubes in a cyclic stacking manner through hydrogen bonding. However, studies exploring other assembly strategies are scarce. In this context, we proposed a new assembly strategy based on cyclic peptides with covalent self-assembly. Here, cyclic peptide-(DPDPDP) was rationally designed and used as a building block to construct new assemblies. With cyclo-(DP)3 as the structural unit and 2,2'-diamino-N-methyldiethylamine as the linker, positively charged nanospheres ((CP)6NS) based on cyclo-(DP)3 were successfully constructed by covalent self-assembly. We assessed their size and morphology by scanning electron microscopy (SEM), TEM, and DLS. (CP)6NS were found to have a strong positive charge, so they could bind to siRNA through electrostatic interactions. Confocal microscopy analysis and cell viability assays showed that (CP)6NS had high cellular internalization efficiency and low cytotoxicity. More importantly, real-time polymerase chain reaction (PCR) and flow cytometry analyses indicated that (CP)6NS-siRNA complexes potently inhibited gene expression and promoted tumor cell apoptosis. These results suggest that (CP)6NS may be a potential siRNA carrier for gene therapy.

[Long term maintenance of cytochrome P450 activity in a cell sheet-based three-dimensional human hepatic model].

Primary human hepatocytes (PHH) are the gold standard of in vitro human liver model for drug screening. However, a problem of culturing PHH in vitro is the rapid decline of cytochrome P450 (CYP450) activity, which plays an important role in drug metabolism. In this study, thermo-responsive culture dishes were used to explore the conditions for murine embryonic 3T3-J2 fibroblasts to form cell sheet. Based on the cell sheet engineering technology, a three-dimensional (3D) "sandwich" co-culture system of 3T3-J2 cell sheet/PHH/collagen gel was constructed. The tissue structure and protein expression of the model section were observed by hematoxylin eosin staining and immunofluorescence staining respectively. Phenacetin and bupropion were used as substrates to determine the activity of CYP450. The contents of albumin and urea in the system were determined by enzyme linked immunosorbent assay (ELISA). The results showed that the complete 3T3-J2 cell sheet could be obtained when the cell seeding density was 1.5×106 /dish (35 mm dish) and the incubation time at low temperature was 60 min. Through cell sheet stacking, a 3D in vitro liver model was developed. Compared with the two-dimensional (2D) model, in the 3D model, the cell-cell and cell-matrix connections were tighter, the activities of cytochrome P450 CYP1A2 and cytochrome P450 CYP2B6 were significantly increased, and the secretion levels of albumin and urea were increased. These indexes could be maintained stably for 21 d. Therefore, cell sheet stacking is helpful to improve the level of liver function of 3D liver model. This model is expected to be used to predict the metabolism of low-clearance drugs in preclinical, which is of great significance for drug evaluation and other studies.

Ferulic Acid Supplementation Increases Lifespan and Stress Resistance via Insulin/IGF-1 Signaling Pathway in C. elegans.

Ferulic acid (FA) is a naturally-occurring well-known potent antioxidant and free radical scavenger. FA supplementation is an effective strategy to delay aging, but the underlying mechanism remains unknown. In the present study, we examined the effects of FA on lifespan extension and its mechanism of FA in Caenorhabditis elegans (C. elegans). Results suggested that FA increased the lifespan of C. elegans, rather than altering the growth of E. coli OP50. Meanwhile, FA promoted the healthspan of C. elegans by improving locomotion and reducing fat accumulation and polyQ aggregation. FA increased the resistance to heat and oxidative stress through reducing ROS. The upregulating of the expression of the hlh-30, skn-1, and hsf-1 were involved in the FA-mediated lifespan extension. Furthermore, FA treatment had no impact on the lifespan of daf-2, hlh-30, skn-1, and hsf-1 mutants, confirming that insulin/IGF-1 signaling pathway and multiple longevity mechanisms were associated with the longevity mechanism of FA. We further found that mitochondrial signaling pathway was modulation involved in FA-mediated lifespan extension. With the results from RNA-seq results and mutants lifespan assay. These findings contribute to our knowledge of the lifespan extension and underlying mechanism of action of FA in C. elegans.

Ginsenoside Prolongs the Lifespan of C. elegans via Lipid Metabolism and Activating the Stress Response Signaling Pathway.

Panax ginseng is a valuable traditional Chinese medicine in Northeast China. Ginsenoside, the active component of ginseng, has not been investigated much for its effects on aging and its underlying mechanism(s) of action. Here, we investigated the effects of total ginsenoside (TG), a mixture of the primary active ginsenosides from Panax ginseng, on the lifespan of Caenorhabditis elegans (C. elegans). We found that TG extended the lifespan of C. elegans and reduced lipofuscin accumulation. Moreover, TG increased the survival of C. elegans in response to heat and oxidative stress via the reduction of ROS. Next, we used RNA-seq to fully define the antiaging mechanism(s) of TG. The KEGG pathway analysis showed that TG can prolong the lifespan and is involved in the longevity regulating pathway. qPCR showed that TG upregulated the expression of nrh-80, daf-12, daf-16, hsf-1 and their downstream genes. TG also reduced the fat accumulation and promoted lipid metabolism. Moreover, TG failed to extend the lifespan of daf-16 and hsf-1 mutants, highlighting their role in the antiaging effects of TG in C. elegans. The four main constitution of TG were then confirmed by HPLC and included ginsenoside Re, Rg1, Rg2 and Rd. Of the ginsenosides, only ginsenoside Rd prolonged the lifespan of C. elegans to levels comparable to TG. These findings provided mechanistic insight into the antiaging effects of ginsenoside in C. elegans.

A deuterohemin peptide protects a transgenic Caenorhabditis elegans model of Alzheimer's disease by inhibiting Aß1-42 aggregation.

Alzheimer's disease (AD) is a progressive neurodegenerative brain disease and is the most common cause of dementia in the elderly. The main hallmark of AD is the deposition of insoluble amyloid (Aß) outside the neuron, leading to amyloid plaques and neurofibrillary tangles in the brain. Deuterohemin-Ala-His-Thr-Val-Glu-Lys (DhHP-6), a novel porphyrin-peptide, has both microperoxidase activity and cell permeability. In the present study, DhHP-6 efficiently inhibited the aggregation of Aß and reduced the ß-sheet percentage of Aß from 89.1% to 78.3%. DhHP-6 has a stronger affinity (KD = 100 ±â€¯12 µM) for binding with Aß at Phe4, Arg5, Val18, Glu11 and Glu22. In addition, DhHP-6 (100 µM) significantly prolonged lifespan, alleviated paralysis and reduced Aß plaque formation in the Aß1-42 transgenic Caenorhabditis elegans CL4176 model of AD. Our results demonstrate that DhHP-6 is a potential drug candidate that efficiently protects a transgenic C. elegans model of Alzheimer's disease by inhibiting Aß aggregation.

A dendrimer consisting of a pyrene core and a 9-phenylcarbazole periphery as a multi-functional fluorescent probe for iodide, iron(III) and mercury(II).

A dendrimer (termed G2) containing pyrene as the core and 9-phenylcarbazole (PCZ) on the periphery is shown to be a multi-functional fluorescent probe for iodide, iron(III) and mercury(II). It serves as the fluorometric/colorimetric dual-channel probe for these ions. As a fluorometric probe, the fluorescence of G2 is quenched both by iodide and iron(III). After that, the fluorescence of G2 which has been added iodide will recover when added mercury(II); as a colorimetric probe, the color of G2 solution can turn to yellow only by iodide which will change from yellow to colorless again when adding mercury(II). The color change is sensitive and observed visually at 0.1 mM for iodide. G2 also is an electroactive precursor for preparation of fluorescent films via electropolymerization. The resulting films can be used as the fluorescent films to sense the ions. This is attributed to the presence of a large specific surface, highly cross-linked microstructures and enhanced π conjugation. The electropolymerized film has blue fluorescence with excitation/emission maxima at 365/460 nm. The limits of detection (LOD) of G2 for iodide, iron(III) and mercury(II) were calculated to be 9.3, 37.1 and 22.0 nM in solution and 5.1, 12.0 and 6.1 nM in films, respectively. The linear range is from 2 to 10 µM for G2 electropolymerized films. The detection range is from 2 to 400 µM for iron(III) and mercury(II). The detection range is from 2 to 130 µM for iodide. For a third application, G2 displays compelling sensing performance in environmental systems and in living roundworms. Graphical abstractAs schematic presentation, after adding iodide, the fluorescence of G2 is quenched and the color changes to yellow. When adding Hg2+ to G2-iodide, the fluorescence and color of G2 recover. Iron(III) can also quench G2, but the color does not change.

Carbon Quantum Dots as Fluorescent Probes for Imaging and Detecting Free Radicals in C. elegans.

Uniform and hydrophilic carbon quantum dots (C-QDs) were synthesized by calcination and NaOH treatment from an organo-templated zeolite precursor. The color of luminescence was determined by the concentration of C-QDs. These variable-color C-QDs were applied for the first time in the imaging of Caenorhabditis elegans (C. elegans) as a model organism. The effects of C-QDs and possible behavioral changes in C. elegans were evaluated under treatment conditions. We could clearly observe distribution of C-QDs in C. elegans from the fluorescence images. Furthermore, we observed significant and detectable fluorescence quenching of the C-QDs by free radicals in C. elegans. Our work affirms that C-QDs can be developed as imaging probes and as potential fluorescent quantitative probes for detecting free radicals.

A Novel Peroxidase Mimics and Ameliorates Alzheimer's Disease-Related Pathology and Cognitive Decline in Mice.

Alzheimer's disease (AD) is the most common neurodegenerative disorder in the elderly, which is characterized by the accumulation of amyloid ß (Aß) plaques, oxidative stress, and neuronal loss. Therefore, clearing Aß aggregates and reducing oxidative stress could be an effective therapeutic strategy for AD. Deuterohemin-AlaHisThrValGluLys (DhHP-6), a novel deuterohemin-containing peptide mimetic of the natural microperoxidase-11 (MP-11), shows higher antioxidant activity and stability compared to the natural microperoxidases. DhHP-6 possesses the ability of extending lifespan and alleviating paralysis in the Aß1-42 transgenic Caenorhabditis elegans CL4176 model of AD, as shown in our previous study. Therefore, this study was aimed at exploring the neuroprotective effect of DhHP-6 in the APPswe/PSEN1dE9 transgenic mouse model of AD. DhHP-6 reduced the diameter and fiber structure of Aß1-42 aggregation in vitro, as shown by dynamic light scattering and transmission electron microscope. DhHP-6 exerted its neuroprotective effect by inhibiting Aß aggregation and plaque formation, and by reducing Aß1-42 oligomers-induced neurotoxicity on HT22 (mouse hippocampal neuronal) and SH-SY5Y (human neuroblastoma) cells. In the AD mouse model, DhHP-6 significantly ameliorated cognitive decline and improved spatial learning ability in behavioral tests including the Morris water maze, Y-maze, novel object recognition, open field, and nest-building test. Moreover, DhHP-6 reduced the deposition of Aß plaques in the cerebral cortex and hippocampus. More importantly, DhHP-6 restored the morphology of astrocytes and microglia, and significantly reduced the levels of pro-inflammatory cytokines. Our findings provide a basis for considering the non-toxic, peroxidase mimetic DhHP-6 as a new candidate drug against AD.

Endothelial progenitor cells and a stromal cell-derived factor-1α analogue synergistically improve survival in sepsis.

RATIONALE: Endothelial progenitor cells (EPCs) have been associated with human sepsis but their role is incompletely understood. Stromal cell-derived factor (SDF)-1α facilitates EPC recruitment and is elevated in murine sepsis models. Previous studies have demonstrated that the SDF-1α analog CTCE-0214 (CTCE) is beneficial in polymicrobial sepsis induced by cecal ligation and puncture (CLP) in mice. OBJECTIVES: We hypothesized that exogenously administered EPCs are also beneficial in CLP sepsis and that CTCE provides synergistic benefit. METHODS: Mice were subjected to CLP and administered EPCs at varying doses, CTCE, or a combination of the two. Mouse survival, plasma miRNA expression, IL-10 production, and lung vascular leakage were determined. The in vitro effect of CTCE on miRNA expression and EPC function were determined. MEASUREMENTS AND MAIN RESULTS: Survival was improved with EPC therapy at a threshold of 10(6) cells. In coculture studies, EPCs augmented LPS-induced macrophage IL-10 production. In vivo EPC administration in sepsis increased plasma IL-10, suppressed lung vascular leakage, attenuated liver and kidney injury, and augmented miR-126 and -125b expression, which regulate endothelial cell function and/or inflammation. When subthreshold numbers of EPCs were coadministered with CTCE in CLP mice they synergistically improved survival. We demonstrated that CTCE recruits endogenous EPCs in septic mice. In in vitro analysis, CTCE enhanced EPC proliferation, angiogenesis, and prosurvival signaling while inhibiting EPC senescence. These cellular effects were, in part, explained by the effect of CTCE on miR-126, -125b, -34a, and -155 expression in EPCs. CONCLUSIONS: EPCs and CTCE represent important potential therapeutic strategies in sepsis.

Combined treatment with a CXCL12 analogue and antibiotics improves survival and neutrophil recruitment and function in murine sepsis.

Previous studies demonstrated that the CXCL12 peptide analogue CTCE-0214 (CTCE) has beneficial effects in experimental sepsis induced by cecal ligation and puncture (CLP). We examined the hypothesis that CTCE recruits neutrophils (PMN) to the site of infection, enhances PMN function and improves survival of mice in CLP-induced sepsis with antibiotic treatment. Septic mice (n=15) were administered imipenem (25mg/kg) and CTCE (10 mg/kg) subcutaneously vs. vehicle control at designated intervals post-CLP. CTCE treatment increased PMN recruitment in CLP-induced sepsis as evidenced by increased PMN in blood by 2.4±0.6 fold at 18h, 2.9±0.6 fold at 24h, respectively and in peritoneal fluid by 2.0±0.2 fold at 24h vs. vehicle control. CTCE treatment reduced bacterial invasion in blood (CFU decreased 77±11%), peritoneal fluid (CFU decreased 78±9%) and lung (CFU decreased 79±8% vs. CLP vehicle). The improved PMN recruitment and bacterial clearance correlated with reduced mortality with CTCE treatment (20% vs. 67% vehicle controls). In vitro studies support the notion that CTCE augments PMN function by enhancing phagocytic activity (1.25±0.02 fold), increasing intracellular production of ROS (32±4%) and improving bacterial killing (CFU decreased 27±3%). These composite findings support the hypothesis that specific CXCL12 analogues with ancillary antibiotic treatment are beneficial in experimental sepsis, in part, by augmenting PMN recruitment and function. This article is protected by copyright. All rights reserved.

Redox control of GPx catalytic activity through mediating self-assembly of Fmoc-phenylalanine selenide into switchable supramolecular architectures.

Artificial enzymes capable of achieving tunable catalytic activity through stimuli control of enzymatic structure transition are of significance in biosensor and biomedicine research. Herein we report a novel smart glutathione peroxidise (GPx) mimic with modulatory catalytic activity based on redox-induced supramolecular self-assembly. First, an amphiphilic Fmoc-phenylalanine-based selenide was designed and synthesized, which can self-assemble into nanospheres (NSs) in aqueous solution. The NSs demonstrate extremely low GPx activity. Upon the oxidation of hydroperoxides (ROOH), the selenide can be quickly transformed into the selenoxide form. The change of the molecular structure induces complete morphology transition of the self-assemblies from NSs to nanotubes (NTs), resulting in great enhancement in the GPx catalytic activity. Under the reduction of GSH, the selenoxide can be further reversibly reduced back into the selenide; therefore the reversible switch between the NSs and NTs can be successfully accomplished. The relationship between the catalytic activity and enzymatic structure was also investigated. The dual response nature makes this mimic play roles of both a sensor and a GPx enzyme at the same time, which can auto-detect the signal of ROOH and then auto-change its activity to achieve quick or slow/no scavenging of ROOH. The dynamic balance of ROOH is vital in organisms, in which an appropriate amount of ROOH does benefit to the metabolism, whereas surplus ROOH can cause oxidative damage of the cell instead and this smart mimic is of remarkable significance. We expect that such a mimic can be developed into an effective antioxidant drug and provide a new platform for the construction of intelligent artificial enzymes with multiple desirable properties.

Identification of a novel macrophage-related prognostic signature in colorectal cancer.

Colorectal cancer (CRC) is one of the most prevalent and deadliest illnesses all around the world. Growing proofs demonstrate that tumor-associated macrophages (TAMs) are of critical importance in CRC pathogenesis, but their mechanisms remain yet unknown. The current research was designed to recognize underlying biomarkers associated with TAMs in CRC. We screened macrophage-related gene modules through WGCNA, selected hub genes utilizing the LASSO algorithm and COX regression, and established a model. External validation was performed by expression analysis using datasets GSE14333, GSE74602, and GSE87211. After validating the bioinformatics results using real-time quantitative reverse transcription PCR, we identified SPP1, C5AR1, MMP3, TIMP1, ADAM8 as potential biomarkers associated with macrophages in CRC.

[Pediatric oral maxillofacial management and artificial intelligence].

With the enhancement of aesthetic awareness of children's oral maxillofacial development, multi-disciplinary doctors pay attention to children's oral maxillofacial management. Artificial intelligence (AI) technology has been gradually applied to all fields of children's oral maxillofacial management because of its outstanding advantages in medical screening and auxiliary decision-making. This article reviews the application of AI technology in the screening, diagnosis, treatment and follow-up of oral maxillofacial management in children.

Influence of bilateral nasal packing on sleep oxygen saturation after general anesthesia: A prospective cohort study.

Objective: This study aims to evaluate the effect of bilateral nasal packing on sleep oxygen saturation and its influencing factors on the first night after general anesthesia. Method: A total of 36 adult patients who underwent bilateral nasal packing with a nonabsorbable expanding sponge after general anesthesia surgery were prospectively studied. All these patients underwent overnight oximetry tests before and the first night after surgery. The following oximetry variables were collected for analysis: the lowest oxygen saturation (LSAT), the average oxygen saturation (ASAT), the oxygen desaturation index of ≥4% (ODI4), and the percentage of time with oxygen saturation below 90% (CT90). Results: Among the 36 patients, the incidences of both sleep hypoxemia and moderate-to-severe sleep hypoxemia increased with bilateral nasal packing after general anesthesia surgery. All the pulse oximetry variables we studied deteriorated significantly after surgery: both LSAT and ASAT decreased significantly (P < 0.05), while both ODI4 and CT90 increased significantly (P < 0.05). In a multiple logistic regression analysis, body mass index (BMI), LSAT, and modified Mallampati grade were found to be independently predictive for a larger decrease in LSAT (≥5%) after surgery (all P's < 0.05). Conclusion: Bilateral nasal packing after general anesthesia could induce or aggravate sleep hypoxemia, especially in patients with obesity, relatively normal sleep oxygen saturation, and high modified Mallampati grades.

Nasopharyngeal tube effects on alleviating sleep hypoxemia during the first night following velopharyngeal surgery in patients with obstructive sleep apnea syndrome.

STUDY OBJECTIVES: To investigate the feasibility and effectiveness of nasopharyngeal tube (NPT) insertion in alleviating sleep hypoxemia during the first night after velopharyngeal surgery in patients with obstructive sleep apnea syndrome (OSAS). METHODS: In this prospective nonblinded, randomized, controlled study, 46 patients with obstructive sleep apnea syndrome (OSAS) who underwent velopharyngeal surgery were enrolled and randomly allocated to the control group (with no NPT insertion) and the NPT insertion group. Both groups underwent overnight pulse oximetry tests during the first postoperative night. RESULTS: One patient in the NPT insertion group was excluded because of involuntary self-removal of NPT during sleep. A total of 45 patients with OSAS were included for analysis, with 23 in the control group and 22 in the NPT insertion group. No significant differences in preoperative baseline information were found between the two groups. Compared with the patients in the control group, those patients in the NPT insertion group showed a significantly higher value of the lowest oxygen saturation of oximetry during the first postoperative night (85.0 ± 4.0% vs 79.3 ± 8.0%) (P = .005). The percentage of patients with lowest oxygen saturation of oximetry < 80% in the NPT insertion group was only 9.1% (2 of 22), which was significantly lower than 39.1% (9 of 23) in the control group (P = .035). No patient reported unbearable discomfort related to NPT insertion. The most common mild discomfort was occasional pharyngeal foreign body sensation (6 of 22, 27.3%). CONCLUSIONS: NPT insertion could lessen the severity of sleep hypoxemia during the first night after velopharyngeal surgery in patients with OSAS and showed excellent compliance. This method could be a potential alternative option for decreasing the risks of complications related to severe sleep hypoxemia during the early postoperative days. CITATION: Zhang J, Guan S, Zhang C, Du X, Li T, Xiao S. Nasopharyngeal tube effects on alleviating sleep hypoxemia during the first night following velopharyngeal surgery in patients with obstructive sleep apnea syndrome. J Clin Sleep Med. 2023;19(2):303-308.

[Application of U-Net network in automatic image segmentation of adenoid and airway of nasopharynx].

Objective:To explore the effect of fully automatic image segmentation of adenoid and nasopharyngeal airway by deep learning model based on U-Net network. Methods:From March 2021 to March 2022, 240 children underwent cone beam computed tomography（CBCT） in the Department of Otolaryngology, Head and Neck Surgery, General Hospital of Shenzhen University. 52 of them were selected for manual labeling of nasopharynx airway and adenoid, and then were trained and verified by the deep learning model. After applying the model to the remaining data, compare the differences between conventional two-dimensional indicators and deep learning three-dimensional indicators in 240 datasets. Results:For the 52 cases of modeling and training data sets, there was no significant difference between the prediction results of deep learning and the manual labeling results of doctors（P>0.05）. The model evaluation index of nasopharyngeal airway volume: Mean Intersection over Union（MIOU） s （86.32±0.54）%; Dice Similarity Coefficient（DSC）: （92.91±0.23）%; Accuracy: （95.92±0.25）%; Precision: （91.93±0.14）%; and the model evaluation index of Adenoid volume: MIOU: （86.28±0.61）%; DSC: （92.88±0.17）%; Accuracy: （95.90±0.29）%; Precision: （92.30±0.23）%. There was a positive correlation between the two-dimensional index A/N and the three-dimensional index AV/（AV+NAV） in 240 children of different age groups（P<0.05）, and the correlation coefficient of 9-13 years old was 0.74. Conclusion:The deep learning model based on U-Net network has a good effect on the automatic image segmentation of adenoid and nasopharynx airway, and has high application value. The model has a certain generalization ability.

A wet-adhesive carboxymethylated yeast ß-glucan sponge with radical scavenging, bacteriostasis and anti-inflammatory functions for rapid hemostasis.

Local hemostats still face obstacles to efficiently achieving hemostasis and promoting wound healing. Herein, a series of multifunctional well-degradable hemostatic sponges based-on carboxymethylated yeast ß-glucan (CMYG) were fabricated by lyophilization. The porous CMYG sponge not only could absorb blood quickly (44.12 g/g), but also possessed unexpected tissue adhesion (∼30 kPa), and it represented good biocompatibility in vitro on fibroblasts and red blood cells. Notably, compared with the commercial Celox™, the CMYG sponge achieved more rapid hemostasis and significantly reduced blood loss in liver injury rat models by rapid wound block. Interestingly, the developed sponge showed an outstanding effect on antioxidant, anti-infection, anti-inflammatory, and cell proliferation, which are beneficial for further wound repair. Overall, these results suggest that the CMYG sponge is a promising candidate for the clinical management of uncontrollable hemorrhage and the further development of wound dressing materials throughout skin defect repair.

Cell sheet-basedin vitrobone defect model for long term evaluation of bone repair materials.

Development of tissue-engineeredin vitrohuman bone defect models for evaluation of bone repair materials (BRMs) is a promising approach for addressing both translational and ethical concerns regarding animal models. In this study, human bone marrow mesenchymal stem cell sheets were stacked to form a periosteum like tissue. HE staining showed a cell-dense, multilayered structure. BRMs were implanted in the defect area of the three-dimensional (3D) model. The CCK-8 test demonstrated that the 3D model was stronger in resisting the cytotoxicity of three kinds of commercial BRMs than the 2D culture model, which was consistent within vivoresults. After 28 d implantation in the 3D model, western blot and RT-qPCR showed that three materials induced increased expressions of RUNX2, OSX, OCN, OPN, while Materials B and C seemed to have stronger osteoinductivity than A.In vivoexperiments also confirmed the osteoinductivity of the BRMs after 28 and 182 d implantation. Alizarin red staining proved that the mineralized nodules of Materials B and C were more than that of A. The differences of osteogenic properties among three BMRs might be attributed to calcium ion release. This cell sheet-based bone tissue model can resist cytotoxicity of BRMs, demonstrating the priority of long-term evaluation of osteoinductivity of BRMs. Further, the osteoinduction results of the 3D model corresponded to that ofin vivoexperiments, suggesting this model may have a potential to be used as a novel tool for rapid, accurate evaluation of BRMs, and thus shorten their research and development process.

A hydrogen-bonded antibacterial curdlan-tannic acid hydrogel with an antioxidant and hemostatic function for wound healing.

Manufacturing facile and low-cost wound dressings that simultaneously meet the needs of the entire repair process remains the major challenge of effective wound healing. Herein, a series of curdlan-tannic acid hybrid hydrogels were successfully fabricated through the annealing technique. Notedly, when the mixing weigh ratio was 1:1, the hydrogel exhibited excellent physicochemical properties, including swellability, degradability, water retention, porosity, and rheology. Additionally, the hydrogel did not display significant cytotoxicity to fibroblasts and the hemolysis rate at 12 h was 3%. Interestingly, the hybrid hydrogel showed multifunctional properties, including remarkable antioxidant, antibacterial, and rapid hemostasis effects reduce blood loss by 0.35 g, that were achieved through the temperature-dependent release of tannic acid. Moreover, a full-thickness skin defect animal model was used to verify that the multifunctional hydrogel could accelerate wound healing in vivo. These results suggest that this hybrid hydrogel is a promising candidate for the clinical treatment of full-thickness wounds.