A 3D hydrogel loaded with exosomes derived from bone marrow stem cells promotes cartilage repair in rats by modulating immunological microenvironment / 南方医科大学学报

OBJECTIVE@#To assess the efficacy of GelMA hydrogel loaded with bone marrow stem cell-derived exosomes for repairing injured rat knee articular cartilage.@*METHODS@#The supernatant of cultured bone marrow stem cells was subjected to ultracentrifugation separate and extract the exosomes, which were characterized by transmission electron microscopy, particle size analysis and Western blotting of the surface markers. The changes in rheology and electron microscopic features of GelMA hydrogel were examined after loading the exosomes. We assessed exosome release from the hydrogel was detected by BCA protein detection method, and labeled the exosomes with PKH26 red fluorescent dye to observe their phagocytosis by RAW264.7 cells. The effects of the exosomes alone, unloaded hydrogel, and exosome-loaded hydrogel on the polarization of RAW264.7 cells were detected by q-PCR and immunofluorescence assay. We further tested the effect of the exosome-loaded hydrogel on cartilage repair in a Transwell co-culture cell model of RAW264.7 cells and chondrocytes in a rat model of knee cartilage injury using q-PCR and immunofluorescence assay and HE and Masson staining.@*RESULTS@#GelMA hydrogel loaded with exosomes significantly promoted M2-type polarization of RAW264.7 cells (P < 0.05). In the Transwell co-culture model, the exosome-loaded GelMA hydrogel significantly promoted the repair of injured chondrocytes by regulating RAW264.7 cell transformation from M1 to M2 (P < 0.05). HE and Masson staining showed that the exosome-loaded hydrogel obviously promoted cartilage repair in the rat models damage.@*CONCLUSION@#GelMA hydrogel loaded with bone marrow stem cell-derived exosomes can significantly promote the repair of cartilage damage in rats by improving the immune microenvironment.

Analysis of posterior lumbar interbody fusion (PLIF) in treating lumbar degenerative disease in elderly patients / 中国骨伤

<p><b>OBJECTIVE</b>To explore the clinical effects of PLIF surgery for elderly patients with lumbar degenerative disease.</p><p><b>METHODS</b>From March 2010 to May 2013, 28 patients with lumbar degenerative disease, aged more than 80 years were treated with PLIF surgery. There were 10 males and 18 females, aged from 80 to 93 years old with an average of (85.44±3.66) years. Course of disease was from 3 to 20 years. The operation time, intra-operative blood loss, operation complications were recorded and JOA scores and Macnab criteria were used to evaluate the clinical outcomes.</p><p><b>RESULTS</b>All patients were followed up from 12 to 40 months with an average of 26.5 months. The average operation time was (150.00±26.42) min and the average intra-operative blood loss was (373.33±99.88) ml. The pre-operative JOA score was 12.30±2.43, and the corresponding postoperative JOA score at the final follow-up was 24.81±2.09 which was much higher than the preoperative one (P<0.01). According to the modified Macnab criteria to evaluate at the final follow-up, 16 patients got an excellent result, 10 good, 2 fair. In the weeks postoperatively, injuries of nerve root happened in 3 cases, superficial wound infection with delayed healing in 3 cases, and tear of the dural sac accompanied with cerebrospinal fluid leakage in 1 case. After long term follow-up, adjacent segment degeneration and the corresponding spinal canal stenosis occurred in 1 case at 34 months after operation. All cases got successful fusion without any displacement of internal fixation and pseudoarthrosis formation.</p><p><b>CONCLUSION</b>With proper cases, fully preoperative preparation, perfect intra-operative manipulation and active treatment after operation, even advanced ages older than 80 years with lumbar degenerative disease could get satisfactory outcomes after PLIF surgery.</p>

Cell-wall-deficient bacteria: a major etiological factor for psoriasis? / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Psoriasis is a common inflammatory skin disease, yet knowledge of the factors that may induce, trigger, or exacerbate psoriasis is not fully delineated. Recent advances have improved our understanding of the link between psoriasis and cell-wall-deficient bacteria (CWDB) infections. In the present study we assessed the prevalence of CWDB infection in patients with psoriasis.</p><p><b>METHODS</b>The carriage rate of CWDB in the tonsil or pharynx of psoriasis patients, chronic tonsillitis patients and controls were investigated using hypertonic medium. Psoriasis patients with CWDB were randomly assigned to two groups and respectively treated with antibiotics or systemic therapy without antibiotic. Human peripheral blood mononuclear cells (PBMC) from psoriasis patients, chronic tonsillitis patients and control subjects were stimulated with bacteria antigens and extra-cellular levels of interferon-gamma (IFN-gamma) and interleukin (IL)-10 were measured in the supernatants using the ELISA technique, in vitro. Meanwhile, the proliferation ability of PBMC to respond to bacteria antigens was detected by MTT assay.</p><p><b>RESULTS</b>CWDB were isolated from 74.2% of psoriasis patients, 23.5% of chronic tonsillitis patients and only 6.3% of controls. Antibiotic therapy was appropriate for approximately 80% of psoriasis patients with CWDB infection, and in only 8.9% psoriasis patients CWDB infection was detected after antibiotic therapy. Meanwhile, our study showed that CWDB and wide-type bacteria did remarkably enhance the production of IFN-gamma, in vitro, and PBMC proliferation.</p><p><b>CONCLUSION</b>CWDB infection may be a virtual triggering factor in psoriasis by regulating T-cell activation.</p>

Comparative study of vertebral body stress distribution following insertion of artificial lumbar intervertebral disc / 中华外科杂志

<p><b>OBJECTIVE</b>To study vertebral body stress distribution of normal disc, post-Diskectomy and artificial disk respectively by 3-D finite element methods, and to explore artificial intervertebral disk insertion impact on stress distribution of vertebral body.</p><p><b>METHODS</b>Models of normal disk, post-Diskectomy, artificial disk and L(4 - 5) motion segment were established by using finite element software MSC. MARK, then vertebral body stress was analyzed through model of L(4 - 5) motion segment respectively.</p><p><b>RESULTS</b>The vertebral body's stress was the smallest after insertion of artificial intervertebral disk (AID), and its stress distributed equally. But the stress under post-discectomy was bigger than the normal disc's in all the motion state. On the other hand, the stress distribution state of the post-discectomy changed while the spine were in different motion state, during the spine flexion, the stress in the anterior of vertebral body was the biggest; While extension, in the posterior and in right flexion state, the biggest stress was in the right. While vertical compression and rotation, the stress distributed equally.</p><p><b>CONCLUSION</b>The results illustrate that the vertebral body's stress is the smallest after insertion of AID in 3 groups of all motion state, and its stress distributes equally. But the level of vertebral body stress increases after discectomy comparing with the normal group. In generally, it is much more reasonable that the disc is reconstructed with AID because of the biomechanical effect on vertebral body made by AID insertion.</p>