Establishment and characterization of human osteosarcoma cells resistant to pyropheophorbide-α methyl ester-mediated photodynamic therapy.

The present study was performed to establish and characterize new human osteosarcoma cell lines resistant to pyropheophorbide-α methyl ester­mediated photodynamic therapy (MPPa-PDT). MPPa-PDT-resistant cells are isolated from the human osteosarcoma MG63 and HOS cell lines and two resistant populations were finally acquired, including MG63/PDT and HOS/PDT. Cell Counting Kit-8 (CCK-8) assay was used to determine the MPPa-PDT, cisplatin (CDDP) resistance and proliferation of MG63, MG63/PDT, HOS and HOS/PDT cells. The intracellular ROS were analyzed using DCFH-DA staining. The colony formation, invasion and migration of parental and resistant cells were compared. FCM was employed to examine the cell cycle distribution, the apoptosis rate and the proportion of CD133+ cells. The fluorescence intensity of intracellular MPPa was observed by fluorescence microscopy and quantified using microplate reader. The protein levels were assessed by western blotting (WB). Compared with two parental cells, MG63/PDT and HOS/PDT were 1.67- and 1.61-fold resistant to MPPa-PDT, respectively, and also exhibited the resistance to CDDP. FCM assays confirmed that both MG63/PDT and HOS/PDT cells treated with MPPa-PDT displayed a significantly lower apoptosis rate in comparison with their corresponding parental cells. The expression of apoptosis-related proteins (i.e. cleaved-caspase 3 and cleaved­PARP), intracellular ROS and the antioxidant proteins (HO-1 and SOD1) in MG63/PDT and HOS/PDT cells was also lower than that in parental cells. Both MG63/PDT and HOS/PDT cells exhibited changes in proliferation, photosensitizer absorption, colony formation, invasion, migration and the cell cycle distribution as compared to MG63 and HOS cells, respectively. Compared to MG63 and HOS cells, both resistant cell lines had a higher expression of CD133, survivin, Bcl-xL, Bcl-2, MRP1, MDR1 and ABCG2, but a lower expression of Bax. The present study successfully established two resistant human osteosarcoma cell lines which are valuable to explore the resistance-related mechanisms and the approaches to overcome resistance.

Comparison between titanium mesh and autogenous iliac bone graft to restore vertebral height through posterior approach for the treatment of thoracic and lumbar spinal tuberculosis.

OBJECT: To compare the clinical efficacy of titanium mesh cages and autogenous iliac bone graft to restore vertebral height through posterior approach in patients with thoracic and lumbar spinal tuberculosis. METHOD: 59 patients with spinal tuberculosis underwent interbody fusion and internal fixation through posterior approach in our department from January 2011 to December 2013. In group A, 34 patients obtained titanium mesh for the reconstruction of vertebral height, among them 25 patients (group A1) suffered from single-segment spinal tuberculosis, and 9 patients, (group A2) had multi-segment spinal tuberculosis. In group B, 25 patients got autogenous iliac bone graft to restore vertebral height, including 24 patients with single-segment spinal tuberculosis (group B1), and 1 patient with multi-segment spinal tuberculosis (group B2). The clinical efficacy was evaluated based on average operation time, blood loss, hospital stays, hospitalization expenses, visual analog scale (VAS), Oswestry Disability Index (ODI), erythrocyte sedimentation rate (ESR), C-Reactive protein (CRP), neurological function recovery, bony fusion, intervertebral height, Cobb angle and postoperative complications. RESULTS: Final follow-up time was an average of 35.5 months ranging from 15 to 56 months. All patients were completely cured and obtained solid bone fusion. The bony fusion time was 9.4±6.1 months in group A1, 10.2±2.7 months in group A2 and 8.7±3.6 months in group B1. There were no significant difference among three groups (P>0.05). The Cobb correction and restoration of intervertebral height significantly improved compared with those in preoperation, but without significant difference among three groups (P>0.05). The loss of angular correction and intervertebral height in group A1 were found to be less than those in group B1 (P<0.05), but with no significant difference between group A1 and group A2, and between group A2 and group B1 (P>0.05). Patients in group B1 got the most loss of angular correction and intervertebral height. In addition, neurological function was revealed to be significantly improved after surgery. There were significant differences of VAS, ODI, ESR and CRP between preoperation and postoperation at the final follow-up time (P<0.05), with no significant difference among three groups (P>0.05). No statistically significant difference was found when analyzing blood loss, hospital stays, hospitalization expenses, and corrective cost among three groups (P>0.05). Complications included cerebrospinal fluid leakage (2 cases in group A1 and group A2), sinus formation (3 cases in group A1, group A2 and group B1), and intervertebral infection (1 case in group B1), but no implant failure or donor site complications was found in any patient. CONCLUSIONS: Titanium mesh cages could obtain good clinical efficacy comparable to autogenous iliac bone graft when treating single-segment spinal tuberculosis, and may be better than autogenous iliac bone graft for treating multi-segment spinal tuberculosis.

Clinical outcomes of two types of cages used in transforaminal lumbar interbody fusion for the treatment of degenerative lumbar diseases: n-HA/PA66 cages versus PEEK cages.

This study reports the clinical effects of nano-hydroxyapatite/polyamide66 cages (n-HA/PA66 cages) and compares the clinical outcomes between n-HA/PA66 and polyetheretherketone cages (PEEK cages) for application in transforaminal lumbar interbody fusion (TLIF). A retrospective and case-control study involving 124 patients using n-HA/PA66 cages and 142 patients using PEEK cages was conducted. All patients underwent TLIF and had an average of 2-years of follow-up. The Oswestry Disability Index and Visual Analog Scale were selected to assess the pain of low back and leg, as well as neurological status. The intervertebral space height and segmental angle were also measured to estimate the radiological changes. At the 1-year and final follow-ups, the fusion and subsidence rates were evaluated. There was no significant difference between the two groups regarding clinical and radiological results. At the final follow-up, the bony fusion rate was 92.45 and 91.57 % for the n-HA/PA66 and PEEK groups, respectively, and the subsidence rate was 7.55 and 8.99 %, respectively. The study indicated that both n-HA/PA66 and PEEK cages could promote effective clinical and radiographic outcomes when used to treat degenerative lumbar diseases. The high fusion and low subsidence rates revealed that n-HA/PA66 cages could be an alternative ideal choice as the same to PEEK cages for lumbar reconstruction after TLIF.