Taurine attenuates ER stress­associated apoptosis and catabolism in nucleus pulposus cells.

Nucleus pulposus (NP) apoptosis and subsequent excessive degradation of the extracellular matrix (ECM) are key pathological characteristics of intervertebral disc degeneration (IDD). The present study aims to examine the signaling processes underlying the effects of taurine on IDD, with specific focus on endoplasmic reticulum (ER) stress­mediated apoptosis and ECM degradation, in NP cells. To clarify the role of taurine in IDD, NP cells were treated with various concentrations of taurine and IL­1ß or thapsigargin (TG). Cell Counting Kit­8, western blotting, TUNEL, immunofluorescence assays and reverse transcription­quantitative PCR were applied to measure cell viability, the expression of ER stress­associated proteins (GRP78, CHOP and caspase­12), apoptosis and the levels of metabolic factors associated with ECM (MMP­1, 3, 9, ADAMTS­4, 5 and collagen II), respectively. Taurine was found to attenuate ER stress and prevent apoptosis in NP cells induced by IL­1ß treatment. Additionally, taurine significantly decreased the expression of ER stress­activated glucose regulatory protein 78, C/EBP homologous protein and caspase­12. TUNEL results revealed that taurine decreased the number of apoptotic TG­treated NP cells. TG­treated NP cells also exhibited characteristics of increased ECM degradation, supported by observations of increased MMP­1, MMP­3, MMP­9 and A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)­4 and ADAMTS­5 expression in addition to decreased collagen­II expression. However, taurine treatment significantly reversed all indicators of excessive ECM catabolism aforementioned. These data suggest that taurine can mediate protection against apoptosis and ECM degradation in NP cells by inhibiting ER stress, implicating therapeutic potential for the treatment of IDD.

Comparison between tension band and cerclage with X-Plate and lag screws in treatment of comminuted patellar fractures.

BACKGROUND: Comminuted patellar fractures are not rare, and the ideal treatment method remains controversial. The present study was conducted to evaluate effects and compare complications of two different methods used to treat comminuted patellar fractures. METHODS: From March 2010 to August 2016, 102 cases of 34-C2 or 34-C3 comminuted patellar fractures were treated at our hospital, wherein patients received two different treatments: titanium cable tension band with cerclage method (group A) and intrafragmentary screws with X-shaped plating technique (group B). At follow-ups, articular step-off, range of motion (ROM), Lysholm scores, time of union, and complications were recorded and analyzed. Radiographic and clinical data as well as rate of complications were statistically analyzed. RESULTS: In total, 87 patients were included in the final analysis (n = 47 in group A and n = 40 in group B). No significant differences were noted in terms of cost of implant, age, gender, rate of 34-C3 fractures, rate of layered inferior pole fractures, postoperative articular step-off and union time. At 2-year follow-up, average Lysholm scores, ROM and rate of complications were (89.0 ± 4.5), (122°±12°) and (27.7%) in group A and (90.2 ± 3.9), (124°±11°) and (17.5%) in group B, respectively, with no significant differences (p > 0.05). The mean time of surgery in group B was shorter than that in group A with significant difference (p < 0.05). CONCLUSIONS: Treatment using the intrafragmentary screws and plate method for amenable comminuted patellar fractures achieved similar complication rate and favorable functional outcomes at the 2-year follow-up, which was comparable to the titanium cable tension band with cerclage method. Thus, the intrafragmentary screws and plate method is effective, safe and convenient for 34-C2/C3 comminuted patellar fractures, especially appropriate for patients with layered fragments.

A clinical comparison study of three different methods for treatment of transverse patellar fractures.

BACKGROUND: Tension bands structures are widely used to treat transverse patellar fractures. However, many implants-related complications have been reported. The purpose of this study is to evaluate effects and compare complications of three methods used to treat transverse patellar fractures, including titanium cable tension bands, compression screws with titanium cable cerclage, and X-shaped plating technique. METHODS: From January 2010 to March 2016, 120 cases of transverse patellar fracture received open reduction and internal fixation with one of three methods: titanium cable tension band (group A), compression screws with titanium cable cerclage (group B), and X-shaped plating technique (group C). Of these, 108 cases were followed for >2 years. Clinical and radiographic data were retrospectively collected and statistically compared. RESULTS: Final analysis included 108 patients (n = 38 in group A, 36 in B, and 34 in C). Reduction was satisfactory in all patients after surgery. No significant differences were noted in age, gender, time from injury to surgery, postoperative articular step-off, Lysholm score, and range of motion at 24 months among all groups. At final follow-up, 12 (31.6%) symptomatic implant complications were encountered in group A, along with 6 (16.7%) and 2 (5.9%) in groups B and C, respectively (p < 0.05). CONCLUSION: All three methods could achieve the goal of rigid fixation and early functional rehabilitation. However, the X-plate technique had the lowest risk of symptomatic implant complications and could thus be a safe and effective alternative for internal fixation of transverse patellar fractures.

[Biomechanics test of fixation of star-shaped six-part patellar fractures with petal-shaped poly-axial locking plate].

Objective: To compare the biomechanical difference between petal-shaped poly-axial locking plate and tension band wire cerclage in fixing star-shaped 6-part patellar fractures in cadaver model, and provide the experimental data for clinical use. Methods: The paired 12 knee specimens from 6 human cadavers were randomly divided into 2 groups (the control group and the test group) after a star-shaped 6-part patellar fracture model was established. The specimens were weighted, and the control group was fixed with tension band wire cerclage and the test group was fixed with petal-shaped poly-axial locking plate. The specimens were connected to CMT5105 biomechanics test machine by a customized fixture, the total fracture gap of patellar fracture blocks was measured before testing. The knee extensor load test was performed to record the extensor load of knees at 90° flexion to extension. Then the anti gravity physiological knee extension process at 90° flexion was stimulated according to the knee extensor load. The cyclic times until failure and the total fracture gap of patellar fracture blocks after failure were recorded. Results: The specimens weight and the total fracture gap of patellar fracture blocks before testing between 2 groups had no significant difference ( t=0.410, P=0.690; t=0.650, P=0.530). In the biomechanical test, there was no significant difference of knee extension load between 2 groups ( t=0.490, P=0.638). The total fracture gap after failure in test group was significantly smaller than that in control group ( t=3.026, P=0.013), and the cyclic times until failure in test group was significantly more than that in control group ( t=2.277, P=0.046). The failure reasons in control group were all the wires slipped off the Kirschner wires, while the failure reasons in test group were the screws pulled out from the upper pole in 5 cases (83.3%) and from the lower pole in 1 case (16.7%). Conclusion: The petal-shaped poly-axial locking plate has better biomechanical stiffness to fix the star-shaped 6-part patellar fractures when compared with tension band wire cerclage method. However, this type of fracture is a serious comminuted type, and the early excessive activity still carries the risk of displacement.

[A finite element analysis of petal-shaped poly-axial locking plate fixation in treatment of Y-shaped patellar fracture].

Objective: To establish the finite element model of Y-shaped patellar fracture fixed with titanium-alloy petal-shaped poly-axial locking plate and to implement the finite element mechanical analysis. Methods: The three-dimensional model was created by software Mimics 19.0, Rhino 5.0, and 3-Matic 11.0. The finite element analysis was implemented by ANSYS Workbench 16.0 to calculate the Von-Mises stress and displacement. Before calculated, the upper and lower poles of the patella were constrained. The 2.0, 3.5, and 4.4 MPa compressive stresses were applied to the 1/3 patellofemoral joint surface of the lower, middle, and upper part of the patella respectively, and to simulated the force upon patella when knee flexion of 20, 45, and 90°. Results: The number of nodes and elements of the finite element model obtained was 456 839 and 245 449, respectively. The max value of Von-Mises stress of all the three conditions simulated was 151.48 MPa under condition simulating the knee flexion of 90°, which was lower than the yield strength value of the titanium-alloy and patella. The max total displacement value was 0.092 8 mm under condition simulating knee flexion of 45°, which was acceptable according to clinical criterion. The stress concentrated around the non-vertical fracture line and near the area where the screws were sparse. Conclusion: The titanium-alloy petal-shaped poly-axial locking plate have enough biomechanical stiffness to fix the Y-shaped patellar fracture, but the result need to be proved in future.

Application of a stand-alone anchored spacer in noncontiguous anterior cervical arthrodesis with radiologic analysis of the intermediate segment.

The purpose of this study was to describe the clinical features of noncontiguous cervical degenerative disc disease (cDDD), investigate the efficacy and complications of a stand-alone anchored spacer (SAAS) for patients with noncontiguous cDDD, and present radiologic analysis of the intermediate segment (IS) after skip-level fusion. Nineteen consecutive patients with noncontiguous cDDD who underwent skip-level anterior cervical discectomy and fusion (ACDF) with SAAS from January 2010 to December 2012 were enrolled in this study. Clinical outcomes were assessed preoperatively and at 24 months postoperatively using the Japanese Orthopaedic Association score, Neck Disability Index, and Visual Analog Scale. Overall cervical alignment (OCA) of the cervical spine, and the range of motion (ROM), intervertebral disc height (IDH), disc signal intensity and disc protrusion of IS were measured and compared before and after surgery. Clinical outcomes significantly improved compared to preoperative scores. The OCA was corrected and maintained at 24 months postoperatively compared with preoperative values (p<0.05). There were no significant differences in the ROM and IDH of the IS at each follow-up (p>0.05). However, decreased signal intensity on T2-weighted MRI was evidenced in three mobile IS at final follow-up (20.0%). Skip-level ACDF with SAAS may be an efficacious option for the treatment of noncontiguous cDDD.

Multistrand titanium cable for the coracoclavicular stabilization of acute acromioclavicular joint dislocation.

The aim of this retrospective study was to evaluate the outcome of the surgical treatment of acute complete acromioclavicular (AC) joint dislocation with multistrand titanium cable for coracoclavicular (CC) stabilization. Forty-two patients with acute complete AC joint dislocation, Rockwood III, IV, V, were treated with CC stabilization using multistrand titanium cable. Thirty-nine patients could be evaluated after a mean follow-up period of 42 months (range, 34-60). The mean VAS score improved from 5.6 +/- 1.5 to 0.4 +/- 1.2 (p < 0.05). The mean Constant score from 64.8 +/- 8.9 preoperatively to 95.3 +/- 9.3 (p < 0.05). Radiographs showed anatomical reduction in 32 out of 39 patients. Cable breakage occurred in 2 patients. CC stabilization with multistrand titanium cables is an effective and safe alternative to other procedures. This procedure provides immediate joint stabilization and allows early mobilization with satisfying functional recovery.

Glucocorticoid induced osteoblast apoptosis by increasing E4BP4 expression via up-regulation of Bim.

It is well known that glucocorticoid (GC)-induced bone loss is caused primarily by hypofunction and apoptosis of osteoblasts. However, the precise molecular events underlying the effect of GC on osteoblast apoptosis are not fully understood. Recent studies implicated an important role of E4BP4 in the regulation of osteoblast apoptosis and differentiation. Furthermore, E4BP4 is a GC-regulated gene required for GC-induced apoptosis in many cells. Therefore, we hypothesize that E4BP4 may be implicated in the process of GC-induced osteoblast apoptosis. Western blot, reverse-transcription-PCR, flow cytometry, and Hoechst 33258 staining were employed to investigate the role of E4BP4 in dexamethasone (DEX)-induced osteoblast apoptosis. We found that the expression of E4BP4 is significantly up-regulated in osteoblasts exposed to DEX. Furthermore, the depletion of E4BP4 significantly decreased DEX-induced osteoblast apoptosis. In addition, E4BP4 plays a crucial role in GC-evoked apoptosis of osteoblasts by enabling induction of Bim. On the basis of these results above, we can draw the conclusion that E4BP4 may contribute to the process of DEX-induced osteoblast apoptosis.

Evaluation of coracoclavicular stabilization of acute acromioclavicular joint dislocation with multistrand titanium cables.

PURPOSE: The aim of this study was to evaluate the outcome of surgical treatment of acute acromioclavicular (AC) joint dislocation with multistrand titanium cables for coracoclavicular (CC) stabilization. METHODS: Forty-two patients with acute AC joint dislocation, including Rockwood type III 14 cases, type IV 2 cases and type V 26 cases, were operated with CC stabilization using multistrand titanium cables. The cables were removed 3-12 months after surgery. The function outcome was evaluated by Constant scores and visual analog scale (VAS) scores. Radiological examination included bilateral antero-posterior and axillary radiography. RESULTS: Three patients were lost to follow-up. Thirty-nine patients had an average follow-up time of 42 months (range 34-60). The Constant scores were 95.3 ± 9.3 at final evaluation. Preoperative and final follow-up VAS scores were 5.6 ± 1.5 and 0.4 ± 1.2, respectively (P < 0.05). Radiographs showed anatomical reduction in 32 patients. Cables breakage occurred in two patients. CONCLUSIONS: CC stabilization with multistrand titanium cables was an effective and safe alternative to other procedures for the treatment of acute high-grade AC joint dislocations. It can provide immediate joint stabilization and allow early mobilization of limb with satisfied functional recovery.

Estrogen inhibits RANKL-induced osteoclastic differentiation by increasing the expression of TRPV5 channel.

The inhibitor effect of estrogen on osteoclasts differentiation is very important in the etiology of estrogen protecting the adult skeleton against bone loss. However, the precise molecular events underlying the effect of estrogen on osteoclasts differentiation are not known. Recent studies implicated an important role of transient receptor potential vanilloid 5 (TRPV5) in osteoclast differentiation and bone resorption. Furthermore, some studies have confirmed that estrogen is involved in the regulation of calcium ion (Ca(2+)) influx in many cells via TRPV5 channel. Therefore, we hypothesize that TRPV5 channel may be implicated in the process of estrogen-inhibited osteoclastogenesis and bone resorption. Western blot, quantitative real-time PCR, tartrate-resistant acid phosphatase (TRAP) staining, and pit formation assay were employed to investigate the role of TRPV5 in estrogen decreasing osteoclast differentiation and bone resorption. We found that the expression of TRPV5 is significantly down-regulated during estrogen deficiency-induced osteoclastogenesis. Furthermore, TRAP staining and pit formation assay showed that the depletion of TRPV5 significantly blocks the inhibitor effects of estrogen on osteoclasts differentiation and bone resorption activity. Further studies confirmed that estrogen regulates the expression of TRPV5 channel via estrogen receptor. Based on these results above, we can draw conclusion that TRPV5 may contribute to the process of estrogen-inhibited osteoclastogenesis and bone resorption activity.