Bone marrow mesenchymal stem cells suppress activated CD4+ T cells proliferation through TGF-beta and IL10 dependent of autophagy in pathological hypoxic microenvironment.

BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) mediated immunomodulation by secreting certain bioactive cytokines has been recognized as a promising approach for disease treatment. However, microenvironmental oxygen tension affect immunomodulatory functions and activate autophagy in BMSCs. The mechanism governing BMSCs immunomodulation in hypoxia hasn't been expounded clearly. The aim of this study is to investigate the function of pathological hypoxia on immunomodulatory properties of bone marrow mesenchymal stem cells and its possible mechanism. METHODS: BMSCs were cultured in either normoxia (21 % oxygen) or hypoxia (0.1 % oxygen) for 24 h, then electron microscopy (EM) and immunofluorescence staining were used to detect the activation of autophagy. Besides autophagy-related markers were monitored by Western blotting. Atg5 siRNA induced autophagic inhibition. Additional, gene expression levels of Real-time fluorescence quantitative PCR and Western blot were used to detect BMSCs related cytokines. Both the proliferation and apoptosis of CD4+ T cell in co-culture were detected by flow cytometry. Exogenous anti-IL-10 antibody and anti-TGF-ß1 antibody were used in co-cultured BMSCs-CM and CD4+ T cells, which enabled us to assess how autophagy affected BMSCs-mediated CD4+ T cell proliferation in low oxygen tension. RESULT: Compared with normal BMSCs, Hypo-BMSCs enhanced the immunosuppressive effect of BMSCs on CD4+ T cell proliferation, while si-atg5 weakened the inhibition of Hypo-BMSCs. Furthermore, exogenous anti-TGF-ß1 antibody and the addition of anti-TGF-ß1 antibody reversed the immunosuppressive ability of Hypo-BMSCs. CONCLUSIONS: Our findings reveal that BMSCs possess significant immunosuppression on CD4+T cell through IL-10 and TGF-ß1 dependent of autophagy in hypoxic microenvironment.

Conditioned medium from human dental pulp stem cells treats spinal cord injury by inhibiting microglial pyroptosis.

Human dental pulp stem cell transplantation has been shown to be an effective therapeutic strategy for spinal cord injury. However, whether the human dental pulp stem cell secretome can contribute to functional recovery after spinal cord injury remains unclear. In the present study, we established a rat model of spinal cord injury based on impact injury from a dropped weight and then intraperitoneally injected the rats with conditioned medium from human dental pulp stem cells. We found that the conditioned medium effectively promoted the recovery of sensory and motor functions in rats with spinal cord injury, decreased expression of the microglial pyroptosis markers NLRP3, GSDMD, caspase-1, and interleukin-1ß, promoted axonal and myelin regeneration, and inhibited the formation of glial scars. In addition, in a lipopolysaccharide-induced BV2 microglia model, conditioned medium from human dental pulp stem cells protected cells from pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1ß pathway. These results indicate that conditioned medium from human dental pulp stem cells can reduce microglial pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1ß pathway, thereby promoting the recovery of neurological function after spinal cord injury. Therefore, conditioned medium from human dental pulp stem cells may become an alternative therapy for spinal cord injury.

Repairing sciatic nerve injury with self-assembling peptide nanofiber scaffold-containing chitosan conduit.

Background: An increasing number of nerve guide scaffolds have been used to replace the "gold-standard" autologous nerve graft for repairing peripheral nerve defects, but nerve regeneration is usually far from complete. Methods: Here, we designed and prepared two functionalized self-assembling peptides (SAP) with the IKVAV and KLT sequences, which were derived from the combination of laminin and VEGF, respectively. Their mixtures were also obtained to combine the effects of neuroprotective and neurotrophic and proangiogenic factors. Results: The beneficial effect of peptide gels on nerve regeneration was evaluated in vitro using Schwann cells (SCs). As a useful intraluminal filling, a three-dimensional (3D) functionalized self-assembling peptide (SAP) nanofiber hydrogel was formed in the hollow lumen of chitosan conduits under physiological conditions. In vivo, the combination of the two functionalized SAP gels containing a chitosan nerve conduit significantly accelerated nerve healing and enhanced morphological repair. Conclusion: Based on the current findings, the combined application of two functionalized SAP gels with chitosan nerve conduit is a promising therapy for the engineering of peripheral nerve regeneration.

Isolated Partial Femoral Avulsion Fracture of the Posterior Cruciate Ligament in Adults.

OBJECTIVE: To investigate the manifestation, mechanisms, and treatment of isolated partial femoral avulsion fractures of the posterior cruciate ligament (PCL) in adults. METHODS: From January 2011 to December 2018, we retrospectively reviewed the clinical data of three patients with isolated partial femoral avulsion fractures of the PCL who were admitted to our institution. All of these patients were admitted to our emergency department within 24 h after injury. After physical examination and radiographs were taken and reviewed, all patients were admitted and underwent surgical treatment. In a 26-year-old man who underwent arthroscopic surgery through the traditional medial and lateral approach before finally converting to open surgery with the posterior approach, the fragment that was finally removed was partially attached to the PCL. In the other two patients, women aged 63 and 68 years, who underwent arthroscopic surgery via the traditional medial and lateral approach, the fragments were large and attached to most fibers of the PCL. We fixed the fragments using hollow screws in arthroscopic view. In addition, in the 63-year-old patient, an anchor was embedded to restore the tension of the PCL. Four weeks after surgery, the patients started to wear long leg braces in full extension with the tibia blocked up by cushion. Physical examinations were conducted and radiographs were taken preoperatively and at 4 weeks and 3 months after surgery to evaluate the condition of the injury. The range of motion and the Lysholm knee scoring scale for the knee joint were compared before and after the surgery. RESULTS: For the three patients, the radiographs taken at 3 months postoperatively showed that the fixation of the screws did not fail, and the subchondral bone was generally normal compared to the preoperative radiographs. CT scanning at 3 months after surgery showed that the fracture healed in the original position of the avulsion site. For all patients, the affected knees presented as stable at physical examination 3 months after surgery; the Lachmann test and the anterior drawer test results were negative. In addition, the flexion-extension, internal rotation, and external rotation were approximately 0°-130°, 0°-30°, and 0°-40° in the 26-year-old patient, respectively. The flexion-extension, internal rotation, and external rotation were approximately 0°-100°, 0°-20°, and 0°-35° for the 63-year-old patient, respectively. The flexion-extension, internal rotation, and external rotation were approximately 0°-100°, 0°-15°, and 0°-20° for the 68-year-old patient, respectively. There was no pain or only little pain 3 months after surgery. There was no swelling or discomfort at the 3-month follow up. The Lysholm knee scores of the 68-year-old, 63-year-old, and 26-year-old patient were 80, 87, and 95 at 3 months after surgery, respectively, which were obviously improved postoperatively. CONCLUSION: The manifestation of isolated partial femoral avulsion fractures of the PCL in adults is often related to the injury mechanism, and surgery is essential for the treatment of these patients. Most of these fractures can be repaired by arthroscopic surgery, but some have to be treated by open surgery.

Antioxidative nanofullerol inhibits macrophage activation and development of osteoarthritis in rats.

Background: There is emerging evidence which suggests that cellular ROS including nitric oxide (NO) are important mediators for inflammation and osteoarthritis (OA). Water-soluble polyhydroxylated fullerene C60 (fullerol) nanoparticle has been demonstrated to have an outstanding ability to scavenge ROS. Purpose: The objective of this study is to assess the effects of fullerol on inflammation and OA by in vitro and in vivo studies. Methods: For in vitro experiments, primary mouse peritoneal macrophages and a macrophage cell line RAW264.7 were stimulated to inflammatory phenotypes by lipopolysaccharide (LPS) in the presence of fullerol. For the animal study, OA model was created by intra-articular injection of monoiodoacetate into the knee joints of rats and fullerol was intravenously injected immediately after OA induction. Results: NO production and pro-inflammatory gene expression induced by LPS was significantly diminished by fullerol in both macrophage cell types. Meanwhile, fullerol could remarkably reduce phosphorylation of p38 mitogen-activated protein kinase, and protein level of transcription factors nuclear factor-kappaB and forkhead box transcription factor 1 within the nucleus. The animal study delineated that systematic administration of fullerol prevented OA, inhibiting inflammation of synovial membranes and the damage toward the cartilage chondrocytes in the OA joints. Conclusion: Antioxidative fullerol may have a potential therapeutic application for OA.