BACKGROUND:Many in vivo and in vitro experiments indicate that hypoxic co-cultures promote stem cells differentiate into chondrocytes.
OBJECTIVE:To evaluate the influence of hypoxia on the chondrogenic differentiation of three-dimensional co-cultured adipose-derived stem cells and articular chondrocytes.
METHODS:Adipose-derived stem cells and articular chondrocytes were mixed at the ratio of 3:1, then the mixed cells were seeded onto poly(lactic-co-glycolic acid)-gelatin scaffold at the ultimate concentration of 5.0×1010/L. The cells were cultured in normoxia (20%O 2 ) and hypoxic (5%O 2 ) conditions for 6 weeks. After culture, hematoxylin and eosin staining was performed for histological structure analysis, and alcian blue staining was used to evaluate glycosaminoglycan synthesis. Type II col agen expression was detected by immunohistochemistry staining. The content of DNA, glycosaminoglycan and hydroxyproline in the scaffold-cellcomplex was measured.
RESULTS AND CONCLUSION:In the hypoxia group, hematoxylin-eosin staining showed the formation of massive cells and extracellular matrix;alcian blue staining showed massive glycosaminoglycan formation;immunohistochemistry staining detected strongly positive expression of col agen type II, the content of DNA, glycosaminoglycan and hydroxyproline was higher than the normoxia group. Hypoxia promotes in vitro chondrogenic differentiation of co-cultured adipose-derived stem cells and articular chondrocytes. .

[ABSTRACT]AIM:TostudytheeffectofsmallinterferingRNA(siRNA)ontheexpressionofbeta2-microglo-bulin (β2M) in pre-differentiated bone marrow mesenchymal stem cells (BMSCs).METHODS: The β2M siRNA was transfected into the pre-differentiated BMSCs with Lipofectamine 2000.BMSCs were divided into transfection group , blank control group and negative control group .The expression of β2 M at mRNA and protein levels was determined by real-time qPCR, Western blotting and laser confocal microscopy .The productions of aggrecan and type II collagen in pre-differentia-ted BMSCs were determined by toluidine blue staining and type Ⅱcollagen immunofluorescence .RESULTS:The results of real-time qPCR, Western blotting and laser confocal microscopy showed that siRNA successfully inhibited the expression ofβ2 M at mRNA and protein levels in the pre-differentiated BMSCs .The results of toluidine blue and type Ⅱcollagen im-munofluorescence staining showed that siRNA does not affect the productions of aggrecan and type Ⅱ collagen in the pre-differentiated BMSCs .CONCLUSION:siRNA targeting β2 M reduces the expression of β2 M in the pre-differentiated BM-SCs and does not affect the chondrocyte characteristics of pre -differentiated BMSCs .

[ABSTRACT]AIM:Toinvestigatetheinhibitoryeffectsofresveratrolonchondrosarcomaandtherelationwith mitochondrial and PI3K/Akt pathways.METHODS:Chondrosarcoma SW1353 cells were treated with resveratrol at con-centrations of 25, 50 and 100 μmol/L for the time intervals of 24 h, 48 h and 72 h.The viability and apoptosis of the SW1353 cells in the presence or absence of resveratrol were analyzed by CCK 8 assay and Hoechst 33258 staining , respec-tively.The protein levels of Bcl-2, Bax, activated caspase-3, Akt and p-Akt were detected by Western blotting .The cell migration ability was determined by wound scratch assay .RESULTS:Exposure of the cells to resveratrol resulted in a de-crease in the cell viability in a dose-and time-dependent manner (P<0.05).visible nuclei with apoptotic characteristics in resveratrol group were observed .The protein levels of activated caspase-3 and Bax were increased , and Bcl-2 and p-Akt were decreased compared with control group .The total Akt were not significantly changed .Resveratrol also significantly re-duced the migration of tumor cells .CONCLUSION:Resveratrol induces apoptosis of chondrosarcoma , which plays a role of part through mitochondrial and PI 3K/Akt signaling pathways .

Objective:To compare the clinical outcomes and complications of oblique lateral interbody fusion combined with bilateral pedicle screw fixation through intermuscular approach and posterior interbody fusion combined with bilateral pedicle screw fixation through intermuscular approach by channel for lumbar spinal stenosis.Methods:A retrospective study was conducted on 73 patients who underwent surgical treatment for lumbar spinal stenosis from Jun 2015 to Jun 2017, including 33 males and 40 females. The average age was 66.8±7.94 years (from 39-85 years). These diseases occured at L 3/4 in 5 patients and L 4/5 in 68 patients. Random according to the time of admission, 38 cases were treated with oblique lateral interbody fusion combined with bilateral pedicle screw fixation through intermuscular approach (oblique lateral fusion group), and 35 cases with posterior interbody fusion combined with bilateral pedicle screw fixation through intermuscular approach by channel (posterior fusion group). The clinical results, image data and complications were compared between the two groups. Results:All patients in both groups had operation performed smoothly. The operation time was 99±8.96 min in the oblique lateral fusion group and 96.8±9.57 min in the posterior fusion group, and there was no significant difference between the two groups. The intraoperative bleeding in the oblique lateral fusion group 80±24.72 ml was significantly less than that in the posterior fusion group 261±52.87 ml ( t=9.621, P<0.05). No incision infection occurred after surgery. The VAS score of lumbar incision 72h after operation in the oblique lateral fusion group 1.21±0.55 was significantly less than that in the posterior fusion group 1.70±0.86 ( t=3.723, P=0.028). The follow-up period lasted for 12-24 months, averagely 17.5±2.58 months. There was statistically significant difference between preoperative and postoperative in the two groups, whether it was the area of the foraminal canal or the area of the spinal canal. There wboth the foraminal area and the spinal canal area were enlarged. The intervertebral space height in the two groups recovered significantly after surgery, the difference was statistically significant. But the intervertebral space height were partly lost at the last follow-up, and there was significant difference compared with postoperative. During the follow-up, no pedicle screw loosening, displacement, rupture, or anterior and lateral displacement of cage occurred. The fusion rate was 97.1% in the posterior fusion group and 100% in the oblique lateral fusion group. There was no statistical difference between the two groups.In terms of ODI index: the posterior fusion group recovered from 48.6±6.1 preoperative to 10.2±2.2 at the last follow-up, and the oblique lateral fusion group recovered from 49.0±5.7 preoperative to 9.3±1.8 at the last follow-up. There was statistically difference between last follow-up and preoperative in the two groups. The incidence of complications in the posterior fusion group was 22.86%, and the incidence in the oblique lateral fusion group was 23.68%. There was no significant difference between the two groups. Conclusion:Both the two decompression and fusion methods have achieved good clinical results in the treatment of lumbar spinal stenosis, with the advantages of less trauma, good stability, fast recovery, and high fusion rate. Compared with posterior decompression and fusion methods, the advantages of OLIF are more obvious, such as less bleeding,lower risk of nerve injury and good indirect decompression of spinal canal. Therefore, the OLIF technique can be a better choice for surgical treatment of lumbar spinal stenosis.

Objective:To investigate the characteristics and causes of endplate injury in the oblique lateral interbody fusion for the treatment of lumbar diseases, and summarize the precaution of endplate injury.Methods:Thirty-five cases of endplate injury were observed, which were originally treated with oblique lateral interbody fusion with or without pedicle screw fixation from October 2014 to December 2017. There were 7 males and 28 females, and the age ranged from 51 to 78 years old (averagely 62.8±8.13 years). There were 2 cases of lumbar disc degeneration, 10 cases of lumbar canal stenosis, 17 cases of lumbar degenerative spondylolisthesis, 2 cases of lumbar spondylolysis with or without spondylolisthesis, and 4 cases of lumbar degenerative scoliosis. Lesion sites contained L 3,4 in 2 cases, L 4,5 in 21 cases, L 2-4 in 3 cases, L 3-5 in 4 cases, L 2-5 in 3 cases and L 1-5 in 2 cases. Preoperative bone mineral density examination revealed there were 7 cases of T>-1 SD, 24 cases of -2.5 SD

Objective:To explore the feasibility and clinical efficacy of oblique lateral interbody fusion (OLIF) in the treatment of adjacent segment disease (ASDis).Methods:Retrospective analysis was conducted on the data of 31 patients with ASDis treated by OLIF in four medical centers from June 2015 to December 2018. There were 17 males and 14 females. The average age was (65.7±3.4) years (range, 59 to 75 years). 19 cases received single-segment fixed fusion, 11 cases received double-segment fixed fusion and 1 case received three-segment fixed fusion. Original fixed fusion site: 1 case of L 1, 2, 3 cases of L 3, 4, 11 cases of L 4, 5, 4 cases of L 5S 1, 6 cases of L 3-L 5, 5 cases of L 4-S 1, and 1 case of L 3-S 1. The time from the initial fixation and fusion to this admission was 82.5±45.5 months (rang, 24 to 180 months). ASDis occurred at the proximal end of the fixed fusion segment in 28 cases and at the distal end in 3 cases. The types of ASDis: degenerative disc disease in 11 cases, lumbar spinal stenosis in 15 cases, degenerative spondylolisthesis in 2 cases, and degenerative scoliosis in 3 cases. The location of ASDis: 6 cases of L 2, 3, 12 cases of L 3, 4, 6 cases of L 4, 5, 3 cases of L 1-L 3, 1 case of L 2-L 4, and 3 cases of L 1-L 4. At admission, 3 cases of lumbar internal fixation had been removed and 28 cases of internal fixation remained. Stand-alone OLIF was performed in 19 cases, OLIF combined with pedicle screw fixation in 8 cases, and OLIF combined with cortical screw fixation in 4 cases. Visual analogue scale (VAS) and Oswestry disability index (ODI) were used to evaluate the low back pain and lumbar function before operation and at the last follow-up, and the imaging results and complications were observed. Results:All patients were followed up. The follow-up time was 23.6±9.6 months (range, 12 to 60 months). The operation time was 73.8±25.3 mins (range, 40 to 180 min), and the intraoperative blood loss was 86.2±67.4 ml (range, 20 to 310 ml). The average blood loss in each segment was 24.8 ml. During the operation, there were 1 case of segmental vein injury, 7 cases of endplate injury, 2 cases of transient iliopsoas muscle weakness, 1 case of thigh pain and numbness, and 1 case of incomplete intestinal obstruction. There was no incision necrosis and infection. The VAS score of low back pain decreased from 5.9±1.9 before operation to 1.4±0.6 at the last follow-up, with a statistically significant difference ( t=8.47, P<0.001). The ODI index recovered from 45.2%±5.7% before operation to 13.8%±4.7% at the last follow-up, with a statistically significant difference ( t=7.92, P<0.001). The height of intervertebral space increased from 8.7±1.6 mm before operation to 11.4±1.9 mm after operation and 9.9±1.8 mm at the last follow-up. There was a statistically significant difference between postoperative and preoperative height of intervertebral space ( F=4.15, P=0.007). There was a statistically significant difference between the last follow-up and postoperative height of intervertebral space ( P=0.011). During the follow-up, there were 13 cases of fusion cage subsidence, 1 case of fusion cage displacement, and no case of internal fixation loosening or fracture. The intervertebral fusion rate was 94%(29/31) and the complication rate was 42%(13/31). Conclusion:ASDis is a common complication after lumbar fixation and fusion, and requires surgical treatment. OLIF is a reliable method to treat ASDis as it has advantages of small trauma, high fusion rate and low complication rate.

The elbow is more susceptible to motion loss than other joints after trauma,and elbow stiffness leads to functional impairment in the upper limb and interferes with daily activities.Open arthrolysis is the most common and classical treatment for post-traumatic elbow stiffness.In this paper,we review the treatment protocols like preoperative clinical evaluation,arthrolysis strategies and postoperative rehabilitation program for post-traumatic elbow stiffness,discuss relevant issues and assess their prospects.

Objective To examine the feasibility and early effects of unilateral pedicle screw fixation in combination with contralateral translaminar facet screw fixation plus interbody fusion through the channel-assisted muscle-splitting approach for the treatment of degenerative lumbar spine diseases in elderly patients.Methods A total of 82 elderly patients with degenerative lumbar spine diseases received treatment between January 2015 and June 2016.Of these patients,25 had lumbar spinal stenosis,42 had degenerative lumbar instability,13 had giant lumbar disc herniation,and two had recurrent lumbar disc herniation;There were 69 cases of single segment and 13 cases of double segment lesions.Perioperative evaluation,imaging evaluation,and clinical evaluation were performed,and surgical complications were analyzed.Results The average length of incision was (2.6 ± 0.4) cm in cases of single segment lesions and (4.4±0.5) cm in cases of two segment lesions.The mean operation time was (98.3±19.6) minutes and peri-operation blood loss was (232.2±25.8) ml.The post-operation height of the intervertebral disc space significantly increased at the last follow-up(P ＜ 0.05);the height of the intervertebral disc space was restored and well maintained with internal fixation showing no loosening,breakage or Cage shift.The post-operation lumbar coronal Cobb angle decreased(P＜0.05)while the sagittal Cobb angle increased(P＜0.05)at the last follow-up.There was no significant difference in the area and grade of the multifidus muscle on MRI 12 months after operation.Seventy-two patients were followed up for 12-18 months (mean =16.8 months),and there were 67 cases of intervertebral fusion (93.1％).The last follow-up showed a Japanese Orthopaedic Association(JOA) score of (25.8 ± 1.7),which was significantly higher than the pre-operation score (10.6±1.3),with an excellence rate of 88.9 ％.The Oswestry Disability Index score was significantly reduced,from (50.9±21.6) at pre-operation to (9.6± 4.8) at the last follow-up.There were 78 patients with primary wound healing,three cases of superficial wound necrosis,one case of dural tear,and one case of nerve root injury.No cardiovascular or cerebrovascular incident was observed during or after operation.Conclusions Combined pedicle/facet screw fixation plus interbody fusion through the channel-assisted muscle-splitting approach shows satisfactory short-term effects when used for the treatment of degenerative lumbar spine diseases in the elderly and possesses advantages such as minimal invasiveness,limited bleeding,quick recovery,high fusion rates and significantly improved clinical outcomes.However,further clinical studies are required to assess its medium-and long-term efficacy.

Drug resistance presents one of the major causes for the failure of cancer chemotherapy. Cancer stem-like cells (CSCs), a population of self-renewal cells with high tumorigenicity and innate chemoresistance, can survive conventional chemotherapy and generate increased resistance. Here, we develop a lipid-polymer hybrid nanoparticle for co-delivery and cell-distinct release of the differentiation-inducing agent, all-trans retinoic acid and the chemotherapeutic drug, doxorubicin to overcome the CSC-associated chemoresistance. The hybrid nanoparticles achieve differential release of the combined drugs in the CSCs and bulk tumor cells by responding to their specific intracellular signal variation. In the hypoxic CSCs, ATRA is released to induce differentiation of the CSCs, and in the differentiating CSCs with decreased chemoresistance, DOX is released upon elevation of reactive oxygen species to cause subsequent cell death. In the bulk tumor cells, the drugs are released synchronously upon the hypoxic and oxidative conditions to exert potent anticancer effect. This cell-distinct drug release enhances the synergistic therapeutic efficacy of ATRA and DOX with different anticancer mechanism. We show that treatment with the hybrid nanoparticle efficiently inhibit the tumor growth and metastasis of the CSC-enriched triple negative breast cancer in the mouse models.

Various c-mesenchymal-to-epithelial transition (c-MET) inhibitors are effective in the treatment of non-small cell lung cancer; however, the inevitable drug resistance remains a challenge, limiting their clinical efficacy. Therefore, novel strategies targeting c-MET are urgently required. Herein, through rational structure optimization, we obtained novel exceptionally potent and orally active c-MET proteolysis targeting chimeras (PROTACs) namely D10 and D15 based on thalidomide and tepotinib. D10 and D15 inhibited cell growth with low nanomolar IC₅₀ values and achieved picomolar DC₅₀ values and >99% of maximum degradation (D_max) in EBC-1 and Hs746T cells. Mechanistically, D10 and D15 dramatically induced cell apoptosis, G1 cell cycle arrest and inhibited cell migration and invasion. Notably, intraperitoneal administration of D10 and D15 significantly inhibited tumor growth in the EBC-1 xenograft model and oral administration of D15 induced approximately complete tumor suppression in the Hs746T xenograft model with well-tolerated dose-schedules. Furthermore, D10 and D15 exerted significant anti-tumor effect in cells with c-MET^Y1230H and c-MET^D1228N mutations, which are resistant to tepotinib in clinic. These findings demonstrated that D10 and D15 could serve as candidates for the treatment of tumors with MET alterations.