Angiopoietin-2 Promotes Mechanical Stress-induced Extracellular Matrix Degradation in Annulus Fibrosus Via the HIF-1α/NF-κB Signaling Pathway

Objective

Mechanical stress is an important risk factor for intervertebral disc degeneration (IVDD). Angiopoietin-2 (ANG-2) is regulated by mechanical stress and is widely involved in the regulation of extracellular matrix metabolism. In addition, the signaling cascade between HIF-1α and NF-κB is critical in matrix degradation. This study aims to investigate the role and molecular mechanism of ANG-2 in regulating the degeneration of annulus fibrosus (AF) through the HIF-1α/NF-κB signaling pathway.

Methods

The bipedal standing mice IVDD model was constructed, and histological experiments were used to evaluate the degree of IVDD and the expression of ANG-2 in the AF. Mouse primary AF cells were extracted in vitro and subjected to mechanical stretching experiments. Western blot assay was used to detect the effect of mechanical stress on ANG-2, and the role of the ANG-2-mediated HIF-1α/NF-κB pathway in matrix degradation. In addition, the effect of inhibiting ANG-2 expression by siRNA or monoclonal antibody on delaying IVDD was investigated at in vitro and in vivo levels. One-way ANOVA with the least significant difference method was used for pairwise comparison of the groups with homogeneous variance, and Dunnett's method was used to compare the groups with heterogeneous variance.

Results

In IVDD, the expressions of catabolic biomarkers (mmp-13, ADAMTS-4) and ANG-2 were significantly increased in AF. In addition, p65 expression was increased while HIF-1α expression was significantly decreased. The results of western blot assay showed mechanical stress significantly up-regulated the expression of ANG-2 in AF cells, and promoted matrix degradation by regulating the activity of HIF-1α/NF-κB pathway. Exogenous addition of Bay117082 and CoCl₂ inhibited matrix degradation caused by mechanical stress. Moreover, injection of neutralizing antibody or treatment with siRNA to inhibit the expression of ANG-2 improved the matrix metabolism of AF and inhibited IVDD progression by regulating the HIF-1α/NF-κB signaling pathway.

Conclusion

In IVDD, mechanical stress could regulate the HIF-1α/NF-κB signaling pathway and matrix degradation by mediating ANG-2 expression in AF degeneration.     

A Comparison of Outcomes between the Wiltse Approach with Pedicle Screw Fixation and the Percutaneous Pedicle Screw Fixation for Multi-Segmental Thoracolumbar Fractures

Objective

Multi-segmental thoracolumbar fracture (MSF) generally refers to fractures occurring in two or more segments of the thoracolumbar spine. With the development of minimally invasive concept, there is little research on its application in the field of MSF. The purpose of this study is to compare two minimally invasive surgical techniques and determine which one is more suitable for treating patients with neurologically intact MSF.

Methods

We retrospectively analyzed the clinical data of 49 MSF patients with intact nerves who were admitted from January 2017 to February 2019. Among them, 25 cases underwent percutaneous pedicle screw fixation (PPSF), and 24 cases underwent Wiltse approach pedicle screw fixation (WAPSF). The operation time, number of fixed segments, blood loss, length of incision, postoperative ambulation time, accuracy of pedicle screw placement, facet joint violation (FJV), number of C-arm exposures, as well as pre- and postoperative visual analogue scale (VAS), Oswestry disability index (ODI), local Cobb's angle (LCA), and percentage of anterior vertebral body height (PAVBH) were recorded for both groups. Paired sample t-test was used for intra-group comparison before and after surgery while independent sample t-test was used for inter-group comparison.

Results

The differences in the number of fixed segments, intraoperative bleeding, postoperative bed time, accuracy rate of pedicle screw placement, VAS, and ODI between the two groups were not statistically significant (p > 0.05). However, the operative time and total surgical incision length were significantly shorter in the WAPSF group than in the PPSF group (p < 0.05), and the FJV was significantly higher in the PPSF group than in the WAPSF group (p < 0.05). Also, the PPSF group received more intraoperative fluoroscopy (p < 0.05). The result of LCA and PAVBH in the WAPSF group were significantly better than in the PPSF group (p < 0.05).

Conclusions

Both PPSF and WAPSF were found to be safe and effective in the treatment of MSF without neurological deficits through our study. However, considering radiation exposure, FJV, vertebral height restoration, correction of kyphosis, and learning curve, WAPSF may be a better choice for neurologically intact MSF.     

Recent Therapeutic Strategies for Excessive Chondrocyte Death in Osteoarthritis: A Review

Osteoarthritis (OA) causes pain and disability in the elderly and has placed a severe burden on healthcare worldwide. Excessive death and decreased density of chondrocytes are recognized as the major pathological characteristic of OA. Chondrocytes have been shown to have multiple forms of death, including apoptosis, pyroptosis, necroptosis, and ferroptosis. The excessive death of chondrocytes often forms a vicious circle with imbalanced chondrocytes extracellular matrix (ECM) metabolism. Therefore, inhibiting chondrocytes excessive death has become a key point that cannot be ignored in the development of OA treatment strategies. We summarized recent studies on the functions and mechanisms of different modes of chondrocyte death and potential therapeutic strategies for OA and offered our views. This may provide direction and theoretical support for formulating OA treatment strategies in the future.     

Radiation dose reduction during hysterosalpingography: an application of scanning-beam digital radiography

Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.     

Evaluation of the Mortality in Emergency Department Sepsis score combined with procalcitonin in septic patients

Objective

To determine an effective method for predicting severity of sepsis and 28-day mortality of emergency department (ED) patients, we compared the Mortality in Emergency Department Sepsis (MEDS) score with procalcitonin (PCT), interleukin-6 (IL-6), and C-reactive protein (CRP) and evaluated the MEDS score combined with relevant biomarkers.

Methods

A total of 501 adult ED patients with sepsis were selected for this prospective clinical study. The optimal combination was assessed by logistic regression. All cases were divided into the sepsis group (319 cases) and the severe sepsis and septic shock group (182 cases) according to the severity of sepsis, as well as the survivor group (367 cases) and nonsurvivor group (134 cases) according to the 28-day outcomes.

Results

The area under the curve of the MEDS score, PCT, IL-6, and CRP was 0.793, 0.712, 0.695, and 0.681 for severity of sepsis and 0.776, 0.681, 0.692, and 0.661 for 28-day mortality, respectively. Only PCT was an independent predictor when combined with the MEDS score. The new combination of the MEDS score with PCT improved the area under the curve for severity (0.852) and mortality (0.813). This new combination for evaluation of severity had better sensitivity (63.2%), specificity (92.2%), and positive predictive (82.1%) and negative predictive (81.4%) values.

Conclusions

The predictive ability of the MEDS score for severity and 28-day mortality of septic ED patients is better than PCT, IL-6, and CRP levels. The MEDS score combined with PCT enhances the ability of risk stratification and prognostic evaluation.