Jie Hao

SIRT1 protects against apoptosis by promoting autophagy in degenerative human disc nucleus pulposus cells

SIRT1 could protect degenerative human NP cells against apoptosis, and there were extensive and intimate connection between apoptosis and autophagy. Up to now, the role of autophagy in the process of human IVD degeneration is unclear. We sought to explore the relationship between autophagy and human IVD degeneration and to understand whether autophagy is involved in the protective effect of SIRT1 against apoptosis in NP cells. Our results showed that the autophagosomes number, the mRNA level of LC3 and Beclin-1, the protein expression of LC3-II/I and Beclin-1, decreased in NP from DDD. Resveratrol could increase the protein expression of LC3-II/I and Beclin-1, and reduce apoptosis in degenerative NP cells. In contrast, the protein levels of LC3-II/I and Beclin-1 were down-regulated and apoptosis level was significantly up-regulated in treatment with nicotinamide or SIRT1-siRNA transfection. Further analysis identified that the expression of cleaved Caspase3 and apoptosis incidence significantly increased with the pretreatment of bafilomycin A, whether resveratrol was added or not. These suggested that autophagy may play an important role in IVD degeneration, and SIRT1 protected degenerative human NP cells against apoptosis via promoting autophagy. These findings would aid in the development of novel therapeutic approaches for degenerative disc disease treatment.

SIRT1 inhibits apoptosis of degenerative human disc nucleus pulposus cells through activation of Akt pathway

Many studies have demonstrated that SIRT1, an NAD+-dependent deacetylase, reduces apoptosis in several different cells. However, the role of SIRT1 in apoptosis of disc nucleus pulposus (NP) cells remains unclear. The present study was performed to determine whether degenerative human NP would express SIRT1, and to investigate the role of SIRT1 in NP cells apoptosis. The expression of SIRT1 in disc NP of patients (>55xa0years) with lumbar disc degenerative disease (DDD) and the disc NP of patients (<25xa0years) with lumbar vertebra fracture (LVF) was assessed by immunohistochemistry, reverse transcription polymerase chain reaction, and Western blot analysis. The results showed that SIRT1 mRNA and protein levels were greater in LVF disc NP than those in DDD disc NP. Degenerative human NP cells were treated in culture with activator or inhibitor of SIRT1, resveratrol or nicotinamide, or SIRT1 small interfering RNA (siRNA), and cell apoptosis was quantified via flow cytometry. The rate of apoptosis was far fewer in resveratrol-treated NP cells than in SIRT1 siRNA-transfected or nicotinamide-treated NP cells. After SIRT1 siRNA was transfected, NP cells decreased phosphorylation of Akt, while resveratrol phosphorylated Akt. Treatment with LY294002 or Akt siRNA increased the rate of apoptosis. Our results suggested that SIRT1 plays a critical role in survival of degenerative human NP cells through the Akt anti-apoptotic signaling pathway.

SIRT1 alleviates senescence of degenerative human intervertebral disc cartilage endo-plate cells via the p53/p21 pathway

Cartilage end plates (CEP) degeneration plays an integral role in intervertebral disc (IVD) degeneration resulting from nutrient diffusion disorders. Although cell senescence resulting from oxidative stress is known to contribute to degeneration, no studies concerning the role of senescence in CEP degeneration have been conducted. SIRT1 is a longevity gene that plays a pivotal role in many cellular functions, including cell senescence. Therefore, the aim of this study was to investigate whether senescence is more prominent in human degenerative CEP and whether SIRT1-regulated CEP cells senescence in degenerative IVD as well as identify the signaling pathways that control that cell fate decision. In this study, the cell senescence phenotype was found to be more prominent in the CEP cells obtained from disc degenerative disease (DDD) patients than in the CEP cells obtained from age-matched lumbar vertebral fractures (LVF) patients. In addition, the results indicated that p53/p21 pathway plays an important role in the senescence of CEP cells in vivo and vitro. Furthermore, SIRT1 was found to be capable of alleviating the oxidative stress-induced senescence of CEP cells in humans via p53/p21 pathway. Thus, the information presented in this study could be used to further investigate the underlying mechanisms of CEP.

Posterior transpedicular debridement, decompression and instrumentation for thoracic tuberculosis in patients over the age of 60

AimOur aim was to evaluate the feasibility and efficiency of the application of posterior transpedicular debridement with instrumentation and fusion to the treatment of over 60-year-old patients with thoracic tuberculosis.MethodsFifteen over 60-year-old patients with thoracic tuberculosis treated by posterior transpedicular debridement with instrumentation and fusion between August 2006 and November 2010, seven males and eight females in this study were reviewed, retrospectively. Their age ranged from 61 to 75 (mean age 63.4). The follow-up period ranged from 12 to 51xa0months (mean 30xa0months). The patients were evaluated based on vertebral body loss, kyphotic angle, fusion status of affected segment, visual analog scale (VAS) pain score, and Frankel’s classification.ResultsA solid fusion was achieved in all 15 cases. No postoperative complications, chronic infection, sinus formation or significant loss of deformity correction was noted in these patients. Moreover, VAS score was reduced and Frankel’s grade was recovered in all patients and there was no recurrence of the tuberculous infection.ConclusionsPosterior transpedicular debridement with instrumentation and fusion is a feasible and effective procedure in the treatment for thoracic tuberculosis in patients over the age of 60.

IL-1β induces apoptosis and autophagy via mitochondria pathway in human degenerative nucleus pulposus cells

IL-1β has been reported highly expressed in degenerative intervertebral disc, and our previous study indicated IL-1β facilitates apoptosis of human degenerative nucleus pulposus (NP) cell. However, the underlying molecular mechanism remains unclear. We here demonstrate that IL-1β played a significantly pro-apoptotic effect under serum deprivation. IL-1β decreased Bcl-2/Bax ratio and enhanced cytochrome C released from mitochondria to cytosol, which proved mitochondria-meidated apoptosis was induced. Subsequently, mitochondria damage was detected under IL-1β stimualtion. In addition, IL-1β-mediated injuried mitochondria contributes to activate autophagy. However, pretreatment with the autophagy inhibitor 3-methyladenine showed the potential in further elevating the apoptosis rate induced by IL-1β in NP cells. Our results indicated that the mitochondrial pathway was involved in IL-1β-induced apoptosis of NP cells. Meanwhile, the damaged mitochondria-induced autophagy played a protective role against apoptosis, suggesting a postive feedback mechanism under inflammatory stress.

Low Intensity Pulsed Ultrasound Promotes the Extracellular Matrix Synthesis of Degenerative Human Nucleus Pulposus Cells Through FAK/PI3K/Akt Pathway.

Study Design. In vitro experimental study Objective. To investigate the effect of low-intensity pulsed ultrasound (LIPUS) on the extracellular matrix (ECM) synthesis of degenerative human nucleus pulposus cells and explore the molecular mechanism. Summary of Background Data. LIPUS has been used successfully for bone fracture healing and been proved to be effective in stimulating ECM metabolism in animal intervertebral disc cells. However, whether LIPUS also exerts an anabolic effect on degenerative human nucleus pulposus cells and the possible molecular mechanism is still unclear. Methods. The degenerative human nucleus pulposus cells were cultured in calcium alginate beads. In the LIPUS group, cells were exposed to an average temporal intensity of 30u200amW/cm2 and a frequency of 1.5u200aMHz of LIPUS 20 minutes daily for 1 week. The control group was cultured in the same way but without LIPUS stimulation. The LY294002 group was stimulated by LIPUS and treated with LY294002 simultaneously. The expression of aggrecan, collagen-II, Sox9, tissue inhibitor of metalloproteinase-,1and matrix metalloproteinase-3 were evaluated by Enzyme-Linked Immunosorbent Assay, Western blot or RT-PCR. Expression of signaling proteins involved in FAK/PI3K/Akt pathway was studied by Western blot analysis. Results. LIPUS significantly upregulated expression of aggrecan, collagen-II, Sox9, and tissue inhibitor of metalloproteinase-1 compared with control group, but inhibited secretion of matrix metalloproteinase-3. The study further demonstrated that the upregulation of aggrecan, collagen-II, and Sox9 was related to the activation of focal adhesion kinase (FAK)//PI3K/Akt pathway caused by LIPUS. Moreover, inhibition of PI3K/Akt significantly suppressed the special biological effect activated by LIPUS. Conclusion. LIPUS promotes the ECM synthesis of degenerative human nucleus pulposus cells through activation of FAK/PI3K/Akt pathway. Level of Evidence: N/A

Percutaneous Fibrin Gel Injection under C-Arm Fluoroscopy Guidance: A New Minimally Invasive Choice for Symptomatic Sacral Perineural Cysts

BACKGROUNDnSymptomatic sacral perineural cysts are a common cause of chronic pain. Surgery is one choice for symptom relief but has a high risk of cyst recurrence and complications. As a simple and safe method to manage symptomatic sacral perineural cysts, C-arm fluoroscopy-guided fibrin gel injection may represent a new minimally invasive alternative. To evaluate the efficacy of this new method, we conducted a retrospective study of 42 patients.nnnMETHODS AND FINDINGSnFrom June 2009 to August 2012, a total of 42 patients with symptomatic sacral perineural cysts underwent C-arm fluoroscopy-guided percutaneous fibrin gel injection therapy. Patient outcomes in terms of improvements in pain and neurologic function were evaluated during a follow-up period of 13-39 months. The preoperative and postoperative pain severity were assessed according to a 10-cm visual analog pain scale, and imaging changes were evaluated by magnetic resonance imaging. We also assessed postoperative complications. Most patients experienced benefit from the procedure: twenty-five patients (59.5%) reported excellent recovery, eleven (26.2%) reported good recovery, three (7.1%) reported fair recovery, and three (7.1%) reported poor recovery. The overall effectiveness rate (excellent and good recoveries) was 85.7%. No serious postoperative complications were observed.nnnCONCLUSIONnPercutaneous fibrin gel injection under C-arm fluoroscopy guidance could be a simple, safe and effective treatment option for symptomatic sacral perineural cysts.

Significant Associations Between the A163G and G1181C Polymorphisms of the Osteoprotegerin Gene and Risk of Osteoporosis, Especially in Postmenopausal Women: A Meta-Analysis

OBJECTIVEnWhereas some studies have reported that the osteoprotegerin (OPG) gene is associated with osteoporosis risk in some studies, their results have proved inconclusive. We performed a meta-analysis of studies on the associations between OPG A163G and G1181C polymorphisms and the risk of osteoporosis.nnnMETHODSnA literature search in PubMed, Embase, Web of Science, Cochrane Library, and China Biological Medicine (CBM) databases was conducted to identify all eligible case-control studies published before August 15th, 2013. Pooled odds ratios with their corresponding 95% confidence intervals were used to evaluate the strength of the association under either a fixed- or random-effect model according to the heterogeneity test.nnnRESULTSnTen case-control studies were included with a total of 1673 osteoporosis cases and 1554 healthy controls in this meta-analysis. For the OPG A163G polymorphism, the combined results showed that the G allele of the A163G polymorphism may be associated with an increased risk of osteoporosis. Stratified analyses showed that the magnitude of the effect was similar among the Caucasian and postmenopausal women subgroups. Unlike the A163G polymorphism, the meta-analysis results revealed that the C allele of the G1181C polymorphism may be associated with a decreased risk of osteoporosis, especially in the Asian and postmenopausal women subgroups. No publication bias was detected for either polymorphism.nnnCONCLUSIONnOur findings showed that the G allele of the OPG A163G polymorphism may increase osteoporosis risk, whereas the C allele of the G1181C polymorphism may protect individuals from osteoporosis. Both of these effects were observed in postmenopausal women.

Microsurgery or open cervical foraminotomy for cervical radiculopathy? A systematic review

ObjectiveThe purpose of this article was to systematically review the clinical outcomes of microendoscopic foraminotomy compared with the traditional open cervical foraminotomy.MethodsA literature search of two databases was performed to identify investigations performed in the treatment of cervical foraminotomy with microsurgery or an open approach. Data including blood loss, surgical time, hospital stay, complications, clinical success rate, reduction of arm and neck pain, improvement of neurological function, and repeated surgery rate were summarized, calculated and compared. Results of clinical success were performed by calculattng effect indicators and standard errors based on a single rate to assess heterogeneity in the two groups.ResultsThe initial literature search resulted in 713 articles, of which, 26 were determined as relevant on abstract review. An open foraminotomy approach was performed in 16 and a microsurgery approach in ten studies. The open group demonstrated minimal to moderate heterogeneity, with I2 value of 27xa0%; and microsurgery group demonstrated minimal heterogeneity, with I2 value of 1xa0%. Aggregated data found that patients treated by microsurgery foraminotomy have lower blood loss by 100.1xa0ml (open: 149.5xa0ml, microsurgery: 49.4xa0ml, nu2009=u20091257), shorter surgical time by 24.9xa0minutes (open 88.7xa0minutes, microsurgery 63.8xa0minutes, nu2009=u20091423),and shorter hospital stay by 3.0xa0days (open 4.1xa0days, microsurgery 1.1xa0days, nu2009=u20091350), compared with patients treated by open cervical foraminotomy. The pooled clinical success rate was 89.7xa0% [confidence interval (CI) 87.7–91.6) in the open group versus 92.5xa0% (CI 89.9–95.1) in the microsurgery group, with no statistical difference (pu2009=u20090.095). Overall complication rates were not statistically significant between groups (pu2009=u20090.757). The incidence of dural tears was 1.07xa0%( 12/1121) in patients undergoing microsurgery versus 0.27xa0% (2/745) for open surgery (pu2009=u20090.091). The incidence of infection was 0.54xa0% (6/1121) in patients undergoing microsurgery versus 0.40xa0% (3/745) for open surgery (pu2009=u20090.949). The incidence of root injury was 0.80xa0% (9/1121) in patients undergoing microsurgery versus 1.48xa0% (11/745) for open surgery (pu2009=u20090.166). Revision surgery occurred in 2.32xa0% (27/1163) in the microsurgery group versus 3.35xa0% (28/835) for traditional surgery, with no statistical difference (pu2009=u20090.164). Pooled reduction in visual analogue scale for the arm (VASA) was 75.0xa0% (CI 66.0–84.0) in the open group and 87.1xa0% (CI:76.7, 97.5) in the microsurgery group, with no statistical difference (pu2009=u20090.065). Pooled reduction in VAS of the neck (VASN) was 66.2xa0% (CI:52.2, 80.2) in the open group and 68.1xa0% (CI:36.4, 99.8) in the microsurgery group, with no statistical difference(pu2009=u20090.894). Pooled improvement in neurological function was 55.3xa0% (CI:18.6, 91.9) in the open group and 64.9xa0% (CI:34.6, 95.2) in the microsurgery group, with no statistical difference (pu2009=u20090.576).ConclusionsAlthough advantages of cervical microsurgery are less blood loss and shorter surgical time and hospital stay over the standard open technique, there is no significant difference in clinical success rate, complication rate, reduction of arm and neck pain and improvement of neurological function between microsurgery and open cervical foraminotomy.

Dickkopf-1 is involved in BMP9-induced osteoblast differentiation of C3H10T1/2 mesenchymal stem cells.

Bone morphogenetic protein 9 (BMP9) is a potent inducer of osteogenic differentiation of mesenchymal stem cells. The Wnt antagonist Dickkopf-1 (Dkk1) is involved in skeletal development and bone remodeling. Here, we investigated the role of Dkk1 in BMP9-induced osteogenic differentiation of MSCs. We found that overexpression of BMP9 induced Dkk1 expression in a dose-dependent manner, which was reduced by the P38 inhibitor SB203580 but not the ERK inhibitor PD98059. Moreover, Dkk1 dramatically decreased not only BMP9-induced alkaline phosphatase (ALP) activity but also the expression of osteocalcin (OCN) and osteopontin (OPN) and matrix mineralization of C3H10T1/2 cells. Furthermore, exogenous Dkk1 expression inhibited Wnt/β-catenin signaling induced by BMP9. Our findings indicate that Dkk1 negatively regulates BMP9-induced osteogenic differentiation through inhibition of the Wnt/β-catenin pathway and it could be used to optimize the therapeutic use of BMP9 and for bone tissue engineering. [BMB Reports 2016; 49(3): 179-184]