The Value of Intraoperative Computed Tomography in the Treatment of Zygomatic Complex Fractures.

BACKGROUND: Due to the complex anatomical morphology and lack of anatomic markers on the surface of zygomatic complex (ZMC), the treatment results of ZMC fractures are often suboptimal. PURPOSE: The study aimed to evaluate the effectiveness of intraoperative computed tomography (ICT) in the treatment of unilateral ZMC fractures, and further study the feasibility of ICT to replace early postoperative Computed Tomography (CT). STUDY DESIGN, SETTING, AND SAMPLE: The investigators designed a retrospective cohort study. Adult patients who underwent surgery with unilateral ZMC fractures were enrolled. PREDICTOR VARIABLE: According to whether intraoperative CT was used, the subjects were divided into the ICT group and the control group (without ICT). MAIN OUTCOME VARIABLES: Five distances and 3 angles representing bilateral ZMC symmetry were main outcome variables. The differences of outcome variables were compared between the 2 groups and the indices of ICT group were further compared with their postoperative indices. COVARIATES: Demographics (eg age), etiology (eg traffic injury), dysfunction (eg diplopia), and surgical approach (eg vestibular incision) were collected as covariates while we conducted clinical investigation, examination, and implementation. ANALYSES: The data were analyzed using independent-samples t test, paired-samples t test, Mann-Whitney U test, and χ2 test. P value < .05 was considered statistically significant. RESULTS: A total of 60 patients (18 to 59 years) were enrolled in this study. All median values of the measurements in the ICT group were smaller than those in the control group, and the differences of horizontal displacement distance (0.56 vs 1.02 mm), anteroposterior displacement distance (1.69 vs 2.34 mm, 0.90 vs 2.35 mm), horizontal angle of bilateral zygomatic arch (2.31 vs 4.19°), and horizontal angle of bilateral zygomatic process (1.77 vs 2.94°) were significantly different between the 2 groups with P value < .05. Moreover, there was no statistically significant difference in all indices between the intraoperatively and postoperatively injured sides in the ICT group. CONCLUSIONS: ICT can improve the treatment outcomes of ZMC fractures by evaluating the fracture reduction adequacy during surgery. Moreover, ICT can replace early postoperative CT.

The Role of Intraoperative Navigation in Surgical Treatment of Unilateral Zygomatic Complex Fractures: A Systematic Review and Meta-Analysis.

PURPOSE: The application of a computer-aided navigation system (CANS) in zygomatic complex (ZMC) fractures has been extensively reported, but individual results are heterogeneous. The purpose of this systematic review was to evaluate the role of CANS in the surgical treatment of unilateral ZMC fractures. METHODS: Electronic retrieval of MEDLINE, Embase, and Cochrane Library (CENTRAL) and manual searching until November 1, 2022 were used to identify cohort studies and randomized controlled trials employing CANS in the surgical treatment of ZMC fractures. The identified reports contained at least 1 of the following outcome variables: accuracy of reduction, total treatment time, amount of bleeding, postoperative complications, satisfaction, and cost. Weighted or mean differences (MD), risk ratios, and corresponding 95% confidence intervals (CI) were calculated, where P＜.05 and I2＞50% random-effect model was adopted, and a vice versa fixed-effect model was adopted. Descriptive analysis was applied to qualitative statistics. The protocol was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and prospectively registered with PROSPERO (CRD42022373135). RESULTS: A total of 562 studies were identified, of which 2 cohort studies and 3 randomized controlled trials with 189 participants were included. Meta-analysis indicated that employing CANS significantly decreased the reduction error (MD = -0.86, 95% CI -1.58 to -0.14; P = .02, random-effect model) compared with conventional surgery without using CANS. The differences in total treatment time (preoperative planning time: MD = 1.44, 95% CI -3.55 to 6.43; P = .57 and operative time: MD = 3.02, 95% CI -9.21 to 15.26; P = .63, fixed-effect model) and amount of bleeding (MD = 14.86, 95% CI -8.86 to 38.58; P = .22, fixed-effect model) were not statistically significant between the two groups. Descriptive analysis suggested that postoperative complications, postoperative satisfaction, and cost were also similar with or without CANS. CONCLUSION: Within the limitations of the present review, the reduction accuracy of unilateral ZMC fractures using CANS is superior to that of conventional surgery. CANS presents limited influence on operation time, amount of bleeding, postoperative complications, postoperative satisfaction, and cost.

Role of Intraoperative Imaging in Improving Closed Reduction of Zygomatic Arch Fractures: A Systematic Review and Meta-analysis.

PURPOSE: The use of intraoperative imaging (IOI) to improve the reduction adequacy of zygomatic arch (ZMA) fractures has been reported, but few systematic reviews have examined this topic. The aim of this review was to investigate and compare the value of IOI with conventional methods without IOI (N-IOI) for the closed reduction of ZMA fractures. METHODS: Electronic retrieval of MEDLINE, Embase, Cochrane Library, Web of Science, Scopus, and citation search until December 2, 2022, was used to identify controlled clinical trials that employed IOI for improving adequacy in closed reduction of ZMA fractures. The predictor variable was the use of IOI-yes/no (IOI vs N-IOI). The covariates included imaging technique (ultrasound, C-arm, and cone beam computed tomography) and ZMA fracture type (M-shape fracture, mechanistic force in 1 direction; variable fracture, mechanistic force in 2 directions). The primary outcome variables were the reduction adequacy of ZMA fractures (the remaining cortical step and dislocation angle) compared with the ideal mirrored position. Weighted or mean differences, risk ratios, and corresponding 95% confidence intervals were calculated, where P >.05 and I2＜50% fixed effect model was adopted, and a vice versa random effect model was adopted. RESULTS: A total of 1250 studies were identified, of which 6 studies with 259 participants were included. The meta-analysis results indicated that compared with N-IOI, IOI yielded fewer cortical steps (-1.76 [-2.42, 1.10], P ＜.00001, fixed model) and dislocation angles (-5.60 [-8.08, 3.12], P＜.00001, fixed model) in patients with variable ZMA fractures, while no significant difference was detected in the M-shape ZMA fracture (-0.72, [-2.93, 1.48], P = .52; -1.48, [-3.51, 0.55], P = .15). Although there was no significant difference in postoperative correction (0.35, [0.06, 2.01] P = .24, fixed model), all secondary revision cases occurred in the N-IOI group. Descriptive analysis showed that IOI yielded better symmetry and appearance satisfaction. CONCLUSION: IOI improved the adequacy of the procedure and led to a better postoperative appearance, especially for patients with variable ZMA fractures. Furthermore, the use of IOI avoided the risk of secondary surgery. In future studies, researchers should standardize the scale and outcomes to facilitate the intuitive evaluation of reduction adequacy.

Anlotinib in recurrent or metastatic endometrial cancer.

OBJECTIVE: For recurrent or metastatic endometrial cancer after second-line treatment, therapeutic options are limited. Anlotinib is a new multi-targeted tyrosine kinase inhibitor of tumor angiogenesis and growth. The aim of this study was to explore the efficacy and safety of anlotinib in patients with recurrent or metastatic endometrial cancer. METHODS: Patients with recurrent or metastatic endometrial cancer who received anlotinib or anlotinib plus pembrolizumab after second-line treatment between July 2017 and October 2020 were analyzed. Objective response rate, disease control rate, progression-free survival, overall survival, and safety were evaluated. RESULTS: A total of 56 patients were analyzed. The median age was 62 years (range 42-80). The median treatment of anlotinib was 5.9 cycles (range 2-21). The overall objective response rate was 42.9%, and the disease control rate was 75%. 44 (78.6%) patients received anlotinib monotherapy and 12 (21.2%) patients received anlotinib plus pembrolizumab. The objective response rate was 40.9% versus 50% (p=0.52) and the disease control rate was 72.7% versus 83.3% (p=0.59) in the monotherapy group and the combination therapy group, respectively. The median progression-free survival and overall survival from initiation of anlotinib therapy was 6 months (95% CI 4.89 to 7.11) and 13.3 months (95% CI 9.94 to 16.61), respectively. On multivariable Cox analysis, age (>60 vs ≤60 years) was an independent impact factor for both progression-free survival and overall survival, while prior lines of treatment (2 lines vs ≥3 lines) was an independent predictor of progression-free survival. The incidences of grade 3/4 adverse events were hypertension (10.7%), fatigue (7.1%), hand-foot syndrome (7.1%), proteinuria (3.6%), sore throat (3.6%), and hypothyroidism (3.6%). CONCLUSION: Anlotinib is effective and well tolerated in patients with recurrent or metastatic endometrial cancer. It may be considered a choice for patients younger than 60 years and who have had <3 lines of treatment.

Macrophage Infiltration Initiates RIP3/MLKL-Dependent Necroptosis in Paclitaxel-Induced Neuropathic Pain.

Paclitaxel (PTX) is a commonly used antitumor drug. Approximately 80% of all patients receiving PTX chemotherapy develop chemotherapy-induced peripheral neuropathy (CIPN), limiting the use of PTX. Moreover, CIPN responds poorly to conventional analgesics. Experimental evidence suggests that the neuroinflammatory response plays an essential role in paclitaxel-induced peripheral neuropathy (PIPN). Previous studies have confirmed that dorsal root ganglion (DRG) neuron necroptosis and accompanying inflammation are linked with PIPN; however, the potential upstream regulatory mechanisms remain unclear. Preclinical studies have also established that macrophage infiltration in the DRG is associated with PIPN. TNF-α released by activated macrophages is the primary regulatory signal of necroptosis. In this study, we established a rat model of PIPN via quartic PTX administration (accumulated dose: 8 mg/kg, i.p.). The regulatory effect of macrophage infiltration on necroptosis in PIPN was observed using a macrophage scavenging agent (clodronate disodium). The results showed that PTX increased macrophage infiltration and the levels of TNF-α and IL-1ß in the DRG. PTX also upregulated the levels of necroptosis-related proteins, including receptor-interacting protein kinase (RIP3) and mixed-lineage kinase domain-like protein (MLKL) in DRG neurons and promoted MLKL phosphorylation, resulting in neuronal necrosis and hyperalgesia. In contrast, clodronate disodium effectively removed macrophages, reduced the levels of RIP3, MLKL, and pMLKL, and decreased the number of necrotic cells in the DRG of PIPN rats, alleviating the behavioral pain abnormalities. These results suggest that PTX promotes macrophage infiltration, which results in the release of TNF-α and IL-1ß in the DRG and the initiation of neuronal necroptosis via the RIP3/MLKL pathway, ultimately leading to neuropathic pain.

RIP3/MLKL pathway-regulated necroptosis: A new mechanism of paclitaxel-induced peripheral neuropathy.

Paclitaxel (PTX) chemotherapy treatment often leads to neuropathic pain, which is resistant to available analgesic treatments. Death of cells and neuroinflammatory response are associated with PTX-induced peripheral neuropathy (PIPN). Necroptosis is a form of regulated necrotic cell death that accompanies strong inflammatory response. It is mediated by receptor-interacting protein kinase 3 (RIP3) and mixed-lineage kinase domain-like protein (MLKL), which contribute to the pathogenesis of several neurodegenerative diseases. Nevertheless, the role of necroptosis in PIPN remains unexplored. The aim of this study was to investigate the role of necroptosis in PIPN using its antagonists (necrostatin-1 and Nec-1). The quartic PTX administration (accumulated dose: 8 mg/kg, ip) in rats induced robust hyperalgesia and allodynia with significant cell necrosis and an increase in proinflammatory cytokines in the dorsal root ganglion (DRG). PTX application also increased RIP3 and MLKL protein levels in DRG, which were primarily in neurons. Moreover, it also promoted satellite glial cells (SGCs) activation, as assayed by glial fibrillary acidic protein (GFAP) upregulation. All these PTX-induced changes were prevented by the Nec-1 treatment. When taken together, the present study indicated that RIP3/MLKL pathway-regulated neuronal necroptosis, which promoted an inflammatory cascade reaction in DRG, might be a new mechanism of PIPN.

The Application of Intraoperative Computed Tomography in Surgical Management of Temporomandibular Joint Ankylosis.

PURPOSE: To investigate the application and value of intraoperative computed tomography (CT) in the surgical management of temporomandibular joint (TMJ) ankylosis. PATIENTS AND METHODS: Patients who underwent surgery of TMJ ankylosis with the aid of intraoperative CT scan from July 2016 to December 2018 were retrospectively studied. Demographics, type of ankylosis, surgical method, intraoperative CT scan time, radiographic evidence, the CT-directed revision rate, and clinical outcomes were analyzed. RESULTS: Four patients (5 sides) were successfully operated with the aid of intraoperative CT imaging, and CT-directed revisions were made in 3 of them during surgery. The average time spent in CT scanning was (10.2 ± 3.3) minutes. No surgical complications were noted, and a good satisfaction rate (with an average maximum mouth opening of 38.8 mm and no recurrence during the follow-up period) was obtained. CONCLUSIONS: Intraoperative CT scanning is a helpful tool in the evaluation of the radiographic result of TMJ ankylosis, and a real-time revision could be made. It increased the precision and safety of the surgery of TMJ ankylosis.

Identification of functional long non-coding RNAs in gastric cancer by bioinformatics analysis.

Long non-coding RNAs (lncRNAs) have been proven to play important roles in various cancers, including gastric cancer (GC). However, detailed knowledge about lncRNAs in GC is limited. Therefore we carried out an in-depth study of public data and found 83 differently expressed lncRNAs in GC. To further confirm the target genes of these lncRNAs, we constructed a co-expression network between lncRNAs and mRNAs and found three lncRNAs (MBNL1-AS1, HAND2-AS1 and MIR100HG) were at the core of the network. By coalition analysis of clinical information and the three lncRNAs' expression level from The Cancer Genome Atlas (TCGA) and GSE15459 data sets, we found MIR100HG could be a potential prognostic factor. Clinical samples showed patients with higher MIR100HG expression had poorer prognosis, and further experiments demonstrated that MIR100HG was associated with proliferation, migration and invasion of GC cells. Hopefully, MIR100HG might be considered as a novel prognostic factor and biomarker for GC.

A prospective Study on Femoral Hernia Repair: Is the Inguinal Better Than The Infrainguinal Approach?

BACKGROUND: Femoral hernia repair has various surgical methods. However, controversy still exists regarding the best method for management. This study aimed to compare the infrainguinal with the inguinal approach in the treatment of femoral hernias. MATERIALS AND METHODS: Eighty patients with primary unilateral femoral hernias were prospectively randomized to either the infrainguinal (n = 40) or inguinal approach groups (n = 40). Patient demographics, operative time, duration of hospital stay, postoperative complications, and recurrence rate were recorded. RESULTS: There were no statistically significant differences between both study groups with respect to the patients' demographics and associated comorbidities. Regarding inpatient outcomes, there were no differences between the infrainguinal and inguinal approach groups concerning the postoperative duration of stay (P = 0.248), urinary retention (P = 0.494), superficial wound infection (P = 0.494), seroma (P = 0.615), foreign body sensation (P = 0.615), and chronic pain (P = 0.359). However, total complications were encountered in 3 patients (7.5%) in the infrainguinal approach group compared to 11 patients (27.5 %) in the inguinal approach group (P = 0.037). Also, the mean operative time was significantly shorter in the infrainguinal approach group compared to that in the inguinal group (P < 0.001). Throughout the 15 mo median follow-up duration, there was no recurrence in the inguinal approach group and one (2.5%) recurrence in the infrainguinal approach group (P = 1.000). CONCLUSIONS: In patients undergoing elective primary femoral hernia repair, the infrainguinal approach has a similar clinical curative effect to that of the inguinal approach. However, the former has the advantages of simple operation, short operation time, and fewer complications.

Long-term results of femoral hernia repair with ULTRAPRO Plug.

BACKGROUND: The infrainguinal plug technique for femoral hernia (FH) has gained popularity for its feasibility, simplicity, and encouraging rate of success, but materials and structures of traditional mesh plugs may cause postoperative discomfort, plug migration, and even recurrence. The new hernia repair device ULTRAPRO Plug (UPP) may avoid those problems. MATERIALS AND METHODS: In 121 of patients, a total of 125 elective FH repairs with UPP were performed between March 2009 and March 2013. Demographics, surgical information, and outcome were assessed. RESULTS: Out of 121 patients, 105 were female. The mean age was 57.6 y. FHs occurred more often on the right (72) than the left (45), and in 4 patients the hernias were bilateral. Mean duration of a hernia surgery was 14.7 min, and 91% patients were discharged within 24 h. Mean time to complete return to daily activities was 7.4 d. No mortality or major complications occurred during the perioperative period. Median follow-up was 26 mo, and the total follow-up rate was 91%. No recurrence or chronic mesh infection was noted. Postoperative chronic pain in two patients, sensory loss in one patient, and foreign body sensation in three patients were found in the follow-up. CONCLUSIONS: Repair of FHs with UPP through an infrainguinal approach is a simple and effective procedure without major postoperative events.

Prevalence of suicide attempts among Chinese adolescents: A meta-analysis of cross-sectional studies.

OBJECTIVE: According to World Health Organization, for every committed suicide there were 20 suicide attempts at least. In the last decade, despite the increasing awareness on suicide attempts among adolescents in China, there has been no comprehensive system reporting vital statistics. Consequently, the prevalence of suicide attempts reported in some studies ranged variedly. Therefore, the purpose of this study was to provide the first meta-analysis of cross-sectional studies of suicide attempts to fill this gap. METHODS: Two reviewers independently screened potentially relevant cross-sectional studies of suicide attempts through PubMed-Medline, Embase, Wanfang Data, Chongqing VIP and Chinese National Knowledge Infrastructure databases using the core terms 'suicid*'/'suicide attempt*'/'attempted suicide' and 'adolescen*'/'youth'/'child*'/'student*' and 'China'/'Chinese' in the article titles, abstracts and keywords. Chi-square based Q test and I(2) statistic assessed the heterogeneity. Forest plot was used to display results graphically. Potential publication bias was assessed by the funnel plot, Begg's and Egger's test. RESULTS: In total, 43 studies with 200,124 participants met the eligibility criteria. The pooled prevalence of suicide attempts among Chinese adolescents was 2.94% (95% CI: 2.53%-3.41%). Substantial heterogeneity in prevalence estimates was revealed. Subgroup analyses showed that the prevalence for males was 2.50% (95% CI: 2.08%-3.01%), and for females was 3.17% (95% CI: 2.56%-3.91%). CONCLUSIONS: In sum, abstracting across the literatures, the prevalence of suicide attempts among Chinese adolescents was moderate compared with other countries around the world. Necessary measures should be set out prevent them in the future.

[Research progress of cell sheet technology and its applications in tissue engineering and regenerative medicine].

Cell sheet engineering is an important technology to harvest the cultured cells in the form of confluent monolayers using a continuous culture method and a physical approach. Avoiding the use of enzymes, expended cells can be harvested together with endogenous extracellular matrix, cell-matrix contacts, and cell-cell contacts. With high efficiency of cell loading ability and without using exogenous scaffolds, cell sheet engineering has several advantages over traditional tissue engineering methods. In this article, we give an overview on cell sheet technology about its applications in the filed of tissue regeneration, including the construction of soft tissues (corneal, mucous membrane, myocardium, blood vessel, pancreas islet, liver, bladder and skin) and hard tissues (bone, cartilage and tooth root). This techonoly is promising to provide a novel strategy for the development of tissue engineering and regenerative medicine. And further works should be carried out on the operability of this technology and its feasibility to construct thick tissues.

Recent Advances in Cell Sheet-Based Tissue Engineering for Bone Regeneration.

In conventional bone tissue engineering, cells are seeded onto scaffolds to create three-dimensional (3D) tissues, but the cells on the scaffolds are unable to effectively perform their physiological functions due to their low density and viability. Cell sheet (CS) engineering is expected to be free from this limitation. CS engineering uses the principles of self-assembly and self-organization of endothelial and mesenchymal stem cells to prepare CSs as building blocks for engineering bone grafts. This process recapitulates the native tissue development, thus attracting significant attention in the field of bone regeneration. However, the method is still in the prebasic experimental stage in bone defect repair. To make the method clinically applicable and valuable in personalized and precision medicine, current research is focused on the preparation of multifunctionalized building blocks using CS technologies, such as 3D layered CSs containing microvascular structures. Considering the great potential of CS engineering in repairing bone defects, in this review, the types of cell technologies are first outlined. We then summarize the various types of CSs as building blocks for engineering bone grafts. Furthermore, the specific applications of CSs in bone repair are discussed. Finally, we present specific suggestions for accelerating the application of CS engineering in the clinical treatment of bone defects.

Hypothermia promotes tunneling nanotube formation and the transfer of astrocytic mitochondria into oxygen-glucose deprivation/reoxygenation-injured neurons.

Mitochondrial transfer occurs between cells, and it is important for damaged cells to receive healthy mitochondria to maintain their normal function and protect against cell death. Accumulating evidence suggests that the functional mitochondria of astrocytes are released and transferred to oxygen-glucose deprivation/reoxygenation (OGD/R)-injured neurons. Mild hypothermia (33 °C) is capable of promoting this process, which partially restores the function of damaged neurons. However, the pathways and mechanisms by which mild hypothermia facilitates mitochondrial transfer remain unclear. We are committed to studying the role of mild hypothermia in neuroprotection to provide reliable evidences and insights for the clinical application of mild hypothermia in brain protection. Tunneling nanotubes (TNTs) are considered to be one of the routes through which mitochondria are transferred between cells. In this study, an OGD/R-injured neuronal model was successfully established, and TNTs, mitochondria, neurons and astrocytes were double labeled using immunofluorescent probes. Our results showed that TNTs were present and involved in the transfer of mitochondria between cells in the mixed-culture system of neurons and astrocytes. When neurons were subjected to OGD/R exposure, TNT formation and mitochondrial transportation from astrocytes to injured neurons were facilitated. Further analysis revealed that mild hypothermia increased the quantity of astrocytic mitochondria transferred into damaged neurons through TNTs, raised the mitochondrial membrane potential (MMP), and decreased the neuronal damage and death during OGD/R. Altogether, our data indicate that TNTs play an important role in the endogenous neuroprotection of astrocytic mitochondrial transfer. Furthermore, mild hypothermia enhances astrocytic mitochondrial transfer into OGD/R-injured neurons via TNTs, thereby promoting neuroprotection and neuronal recovery.

Tuina Inhibits Chondrocyte Apoptosis by Regulating the FAK/PI3K/Akt Pathway in Rabbits with IVDD.

BACKGROUND: Intervertebral disc degeneration (IVDD), a key contributor to degenerative spinal diseases such as cervical spondylosis, significantly influences the quality of life of patients. Tuina, historically employed in the clinical management of cervical spondylosis, has demonstrated positive therapeutic outcomes; however, the mechanism of Tuina remains unclear. OBJECTIVE: This study examined the efficacy of Tuina in correcting the imbalanced structure of the cervical spine and its impact on apoptotic chondrocytes within the cervical disc. The underlying mechanisms were explored using a rabbit model of IVDD induced by dynamic and static imbalances. METHODS: The IVDD rabbit model was established by restraining the head in a downward position for 12 weeks (Model group). In the Tuina1 group, treatment was performed on the posterior cervical trapezius muscle daily for 2 weeks, whereas in the Tuina2 group, treatment was performed on both the posterior cervical trapezius and anterior sternocleidomastoid muscles daily for 2 weeks. After treatment, X-ray, micro-computed tomography (CT), histological staining, qRT-PCR, and western blotting were used to evaluate the mechanism by which Tuina inhibits chondrocyte apoptosis. RESULTS: The results demonstrated that Tuina treatment inhibited chondrocyte apoptosis in cervical discs by adjusting the neck structure balance, and a more significant therapeutic effect was observed in the Tuina2 group. Lateral cervical spine X-ray and CT scans in rabbits revealed notable improvements in cervical spine curvature and vertebral structure in the treatment groups compared with those in the Model group. Hematoxylin and eosin staining and TUNEL staining further confirmed the positive impact of Tuina treatment on intervertebral disc tissue morphology and chondrocyte apoptosis. Additionally, western blotting and immunohistochemical analysis showed that Tuina treatment suppressed chondrocyte apoptosis by downregulating Bax and caspase-3 while upregulating Bcl-2. Western blotting results further indicated that Tuina could activate the FAK/PI3K/Akt signaling pathway by mediating integrin-ß1. CONCLUSION: Tuina treatment inhibited chondrocyte apoptosis in cervical discs by activating the FAK/PI3K/Akt signaling pathway, providing convincing evidence to support Tuina treatment as a promising method for IVDD.

Engineering tubular bone using mesenchymal stem cell sheets and coral particles.

The development of bone tissue engineering has provided new solutions for bone defects. However, the cell-scaffold-based approaches currently in use have several limitations, including low cell seeding rates and poor bone formation capacity. In the present study, we developed a novel strategy to engineer bone grafts using mesenchymal stem cell sheets and coral particles. Rabbit bone marrow mesenchymal stem cells were continuously cultured to form a cell sheet with osteogenic potential and coral particles were integrated into the sheet. The composite sheet was then wrapped around a cylindrical mandrel to fabricate a tubular construct. The resultant tubular construct was cultured in a spinner-flask bioreactor and subsequently implanted into a subcutaneous pocket in a nude mouse for assessment of its histological characteristics, radiological density and mechanical property. A similar construct assembled from a cell sheet alone acted as a control. In vitro observations demonstrated that the composite construct maintained its tubular shape, and exhibited higher radiological density, compressive strength and greater extracellular matrix deposition than did the control construct. In vivo experiments further revealed that new bone formed ectopically on the composite constructs, so that the 8-week explants of the composite sheets displayed radiological density similar to that of native bone. These results indicate that the strategy of using a combination of a cell sheet and coral particles has great potential for bone tissue engineering and repairing bone defects.

The Role of Macrophage Phenotype in the Vascularization of Prevascularized Human Bone Marrow Mesenchymal Stem Cell Sheets.

With the development of tissue engineering and regenerative medicine, prevascularized bone marrow mesenchymal stem cell (BMSC) sheets have been regarded as a promising method for tissue regeneration. Furthermore, the inflammatory response is one of the main regulators of vascularization and the restoration of engineered tissue function; among them, macrophages and cytokines produced by them are considered to be the decisive factors of the downstream outcomes. This study investigated the effect of macrophages on the formation of microvascular-like structures of human umbilical vein endothelial cells (HUVECs) in BMSC sheets. First, a human monocytic leukemia cell line (THP-1 cells) was differentiated into derived macrophages (M0) with phorbol 12-myristate 13-acetate and further activated into proinflammatory macrophages (M1 macrophages) with interferon-γ and lipopolysaccharide or anti-inflammatory macrophages (M2 macrophages) with interleukin-4. Then, HUVECs and prevascularized sheets were treated with conditioned media (CM) from different macrophages, and the impact of macrophage phenotypes on vascularized network formation in prevascularized cell sheets was examined by hematoxylin and eosin staining, CD31 immunofluorescence staining and enzyme-linked immunosorbent assay. Our study showed that macrophages may guide the arrangement of endothelial cells through a paracrine pathway. Cell sheets that were cultured in the CM from M2 macrophages were thinner than those cultured in other media. At various time points, the levels of tumor necrosis factor alpha and vascular endothelial growth factor in prevascularized sheets cultured with CM(M1) was higher than that in sheets cultured with other media; however, the levels of platelet-derived growth factor in prevascularized sheets cultured with CM(M2) was higher than that in sheets cultured with other media. These findings suggest that the paracrine effect of macrophages can influence the formation of microvascular networks in prevascularized sheets by regulating the arrangement of cells, the thickness of the cell sheet and the secretion of cytokines related to angiogenesis. Macrophages with different phenotypes have unique effects on prevascularized sheets.

A novel strategy to engineer small-diameter vascular grafts from marrow-derived mesenchymal stem cells.

Tissue-engineered blood vessels have mainly relied on endothelial cells (ECs), smooth muscle cells (SMCs), and biocompatible materials. However, long-term results have revealed several material-related failures, such as stenosis, thromboembolization, and the risk of infection. Furthermore, SMCs from elderly persons have reduced capacity in proliferation and collagen production. Mesenchymal stem cells (MSCs) have the ability to differentiate into multiple cell lineages, including osteoblasts, chondrocytes, ECs, and SMCs. In the current experiment, rabbit MSCs were cultured to form a cell sheet. A tissue-engineered vascular graft (TEVG) was fabricated by rolling the MSC sheet around a mandrel. The TEVG was implanted into a defect of the common carotid artery after it was examined macroscopically and microscopically. Hematoxylin and eosin staining showed that cell sheet was composed of five to seven layers of cells with the thickness of 40-50 µm. Results from the adhesion assay revealed that MSCs had similar antiplatelet adhesion property to ECs. Histological analysis of TEVGs showed that the layers of the cell sheet had fully fused in vitro. After implantation, TEVGs had excellent patency and integrated well with the native vessel. The structure of the TEVGs was similar to that of the native artery 4 weeks after implantation. Electron microscopy showed that the implanted TEVGs endothelialized. These results indicated that a completely biological TEVG could be assembled with autologous MSCs. These TEVGs are useful for revascularization in humans, which would reduce the occurrence of complications caused by foreign materials.

[Mechanical properties of alginate hydrogels with different concentrations and their effects on the proliferation chondrocytes in vitro].

The mechanical properties of natural and synthetic extracellular matrices affect cellular processes and regulate tissue formation. In order to explore the optimal environment for chondrocytes growth in vitro, we investigated the relationship between the mechanical properties of the alginate beads and the ability of chondrocyte proliferation in this study. We measured the compressive properties of alginate with different concentrations by INSTRON 3365,and found that compressive moduli significantly increased with increasing alginate concentration. The rabbit chondrocytes were encapsulated in 1%, 2% and 3% (w/v) alginate beads at high (1 x 10(7)/ml) density. After 4 week's culturing, all the three groups resulted in the limited proliferation of the chondrocytes and the formation of cell clusters resembling cartilaginous tissues. Chondrocytes proliferation was more rapid on lower concentrate gels (1%, 2%) than on the higher concentrate gels (3%). These results suggested that the mechanical properties of scaffold architecture had certain effect on chondrocytes proliferation.