Lack of bioactivity has seriously restricted the development of biodegradable implants for bone tissue engineering. Therefore, surface modification of the composite is crucial to improve the osteointegration for bone regeneration. Bone morphogenetic protein-2 (BMP-2), a key factor in inducing osteogenesis and promoting bone regeneration, has been widely used in various clinical therapeutic trials. In this study, BMP-2 was successfully immobilized on graphene oxide-incorporated PLGA/HA (GO-PLGA/HA) biodegradable microcarriers. Our study demonstrated that the graphene oxide (GO) facilitated the simple and highly efficient immobilization of peptides on PLGA/HA microcarriers within 120 min. To further test in vitro, MC3T3-E1 cells were cultured on different microcarriers to observe various cellular activities. It was found that GO and HA significantly enhanced cell adhesion and proliferation. More importantly, the immobilization of BMP-2 onto the GO-PLGA/HA microcarriers resulted in significantly greater osteogenic differentiation of cells in vitro, as indicated by the alkaline phosphate activity test, quantitative real-time polymerase chain reaction analysis, immunofluorescence staining and mineralization on the deposited substrates. Findings from this study revealed that the method to use GO-PLGA/HA microcarriers for immobilizing BMP-2 has a great potential for the enhancement of the osseointegration of bone implants.

There is an urgent and unmet need for humanized in vivo models of type 1 diabetes to study immunopathogenesis and immunotherapy, and in particular antigen-specific therapy. Transfer of patient blood lymphocytes to immunodeficient mice is associated with xenogeneic graft-versus-host reactivity that complicates assessment of autoimmunity. Improved models could identify which human T cells initiate and participate in beta-cell destruction and help define critical target islet autoantigens. We used humanized mice (hu-mice) containing robust human immune repertoires lacking xenogeneic graft-versus-host reactivity to address this question. Hu-mice constructed by transplantation of HLA-DQ8 human fetal thymus and CD34 cells into HLA-DQ8-transgenic immunodeficient mice developed hyperglycemia and diabetes after transfer of autologous HLA-DQ8/insulin-B:9-23 (InsB:9-23)-specific T-cell receptor (TCR)-expressing human CD4 T cells and immunization with InsB:9-23. Survival of the infused human T cells depended on the preexisting autologous human immune system, and pancreatic infiltration by human CD3 T cells and insulitis were observed in the diabetic hu-mice, provided their islets were stressed by streptozotocin. This study fits Koch's postulate for pathogenicity, demonstrating a pathogenic role of islet autoreactive CD4 T-cell responses in type 1 diabetes induction in humans, underscores the role of the target beta-cells in their immunological fate, and demonstrates the capacity to initiate disease with T cells, recognizing the InsB:9-23 epitope in the presence of islet inflammation. This preclinical model has the potential to be used in studies of the pathogenesis of type 1 diabetes and for testing of clinically relevant therapeutic interventions.

The currently available human tumor xenograft models permit modeling of human cancers in vivo, but in immunocompromised hosts. Here we report a humanized mouse (hu-mouse) model made by transplantation of human fetal thymic tissue plus hematopoietic stem cells transduced with a leukemia-associated fusion gene MLL-AF9. In addition to normal human lymphohematopoietic reconstitution as seen in non-leukemic hu-mice, these hu-mice showed spontaneous development of B-cell acute lymphoblastic leukemia (B-ALL), which was transplantable to secondary recipients with an autologous human immune system. Using this model, we show that lymphopenia markedly improves the antitumor efficacy of recipient leukocyte infusion (RLI), a GVHD-free immunotherapy that induces antitumor responses in association with rejection of donor chimerism in mixed allogeneic chimeras. Our data demonstrate the potential of this leukemic hu-mouse model in modeling leukemia immunotherapy, and suggest that RLI may offer a safe treatment option for leukemia patients with severe lymphopenia.

CD47-deficient hepatocyte transplantation induces rapid innate immune cell activation and subsequent associated graft loss in syngeneic recipients. However, the role of donor CD47 in regulation of T-cell alloresponses is poorly understood. We addressed this question by assessing OVA-specific immune responses in mice following hepatocyte transplantation from CD47-competent or -deficient OVA-transgenic donors. Compared to sham-operated controls, intrasplenic transplantation of CD47-deficient OVA+ hepatocytes significantly accelerated rejection of OVA+ skin grafted 7 days after hepatocyte transplantation. In contrast, mice receiving CD47-competent OVA+ hepatocytes showed prolonged and even indefinite survival of OVA+ skin allografts. T cells from mice receiving CD47-deficient, but not CD47-competent, OVA+ hepatocytes showed significantly enhanced responses to OVA+ stimulators compared to sham-operated controls. In contrast to the production of tolerogenic cytokines (IL-4 and IL-10) in the recipients of CD47-competent hepatocytes, mice receiving CD47-deficient hepatocytes showed elevated production of IFN-γ and IL-1α. Moreover, significant expansion of myeloid-derived suppressor cells was detected in the recipients of CD47-competent hepatocytes, which was required for tolerance induction in these mice. Thus, donor CD47 plays an important role in the control of T-cell alloresponses and tolerance induction following hepatocyte transplantation. Our data also suggest that intrasplenic hepatocyte transplantation may provide a means to induce allograft tolerance.

Thymic selection constitutes the first checkpoint in T-cell development to purge autoreactive T cells. Most of our understanding of this process comes from animal models because of the challenges of studying thymopoiesis and how T cell receptor (TCR) specificity impacts thymocyte phenotype in humans. We developed a humanized mouse model involving the introduction of autoreactive TCRs and cognate autoantigens that enables the analysis of selection of human T cells in human thymic tissue in vivo. Here, we describe the thymic development of MART1-specific autoreactive CD8+ T cells that normally escape deletion and how their phenotype and survival are affected by introduction of the missing epitope in the hematopoietic lineage. Expression of the epitope in a fraction of hematopoietic cells, including all major types of antigen-presenting cells (APCs), led to profound yet incomplete deletion of these T cells. Upregulation of PD-1 upon antigen encounter occurred through the different stages of thymocyte development. PD-1 and CCR7 expression were mutually exclusive in both transgenic and non-transgenic thymocytes, challenging the view that CCR7 is necessary for negative selection in humans. In the presence of antigen, MART1-reactive T cells down-regulated TCR, CD3, CD8, and CD4 in the thymus and periphery. Moreover, expression of secondary TCRs influences MHC class I-restricted T cells to develop as CD4+, particularly regulatory T cells. This new model constitutes a valuable tool to better understand the development of autoreactive T cells identified in different human autoimmune diseases and the role of different APC subsets in their selection.

No abstract

Esophageal duplication cyst (EDC) is a congenital malformation of the posterior primitive foregut, which mainly occurs in the thoracic esophagus. Here, we describe a 3-year-old Han Chinese boy afflicted with intermittent fever of acute onset and dry cough. Thoracic computed tomography revealed an 10 cm × 5.4 cm × 5.8 cm oval-shaped, cyst-like tumor located in the extrapleural space, extending along the right paravertebral gutter and compressing the trachea forward. An additional small-sized, oval-shaped cyst was identified in the posterior mediastinum, between the esophagus and the spinal column, at the T1 level. During open thoracotomy, under general anesthesia, an opaque, thick-walled, esophageal cyst was revealed not to be in communication with the esophageal lumen or the trachea. This cyst was subsequently resected in an en bloc manner. The small (1-cm) esophageal cyst was left untreated based on a “wait-and-see” policy. Histological analysis showed that the resected cyst was walled by hyperplastic, fibrous tissues and locally lined with gastric mucosa inherent glands. This finding was consistent with a diagnosis of EDC, with ectopic gastric mucosa. The respiratory tract symptoms resolved immediately after the operation. Computed tomography obtained at the 6-month follow-up showed that no disease, residual or recurrence, was present after the resection of the large-sized cyst, and the small-sized cyst remained unchanged in size.

Objective. To assess if the addition of fentanyl to brachial plexus block has an impact on anesthetic outcomes and complication rates in patients undergoing upper extremity surgeries. Methods. We explore the PubMed, Embase, ScienceDirect, CENTRAL, and Google Scholar databases for all randomized controlled trials (RCTs) comparing adjuvant fentanyl with placebo/no drug for patients undergoing upper extremity surgery under brachial plexus block. Outcomes assessed were onset, duration of sensory and motor anesthesia, complications, and postoperative analgesia scores. Meta-analysis was conducted utilizing a random-effects model. The risk of bias was assessed using the Cochrane Collaboration’s risk of bias assessment tool 2. Certainty of evidence was assessed using GRADE. Subgroup analysis was conducted depending upon the approach of brachial plexus block and type of local anesthetic. Results. Twelve RCTs with 660 patients were included. Addition of fentanyl had no effect on onset of sensory anesthesia (11 studies; MD: 0.48; 95% CI: −1.81, 0.85; I2 = 96%; p = 0.48 ) but significantly shortened onset of motor anesthesia (8 studies; MD: −2.36; 95% CI: −3.99, −0.74; I2 = 96%; p = 0.48 ). Duration of sensory anesthesia (9 studies; MD: 82.81; 95% CI: 41.81, 123.81; I2 = 99%; p < 0.0001 ) and motor anesthesia (7 studies; MD: 93.41; 95% CI: 42.35, 144.46; I2 = 99%; p = 0.0003 ) was significantly increased with addition of fentanyl. The certainty of evidence-based on GRADE was deemed to be moderate for both onset and duration of anesthesia. The incidence of overall complications (nausea/vomiting and pruritis) was significantly higher in the fentanyl group (7 studies; OR: 2.14; 95% CI: 1.04, 4.40; I2 = 8%; p = 0.04 ) but with low certainty of evidence. Conclusions. Adjuvant fentanyl with brachial plexus block improves the onset of motor anesthesia but not sensory anesthesia. The duration of both sensory and motor anesthesia is significantly prolonged with fentanyl by around 83–93 minutes. However, clinicians should be aware that complications such as nausea/vomiting and pruritis are increased twofold with the addition of the drug. Current evidence is limited risk of bias in the RCTs and high heterogeneity in the meta-analyses.