Yuan Wang

Intervertebral disc degeneration (IVDD) is a significant contributor to chronic low back pain and disability worldwide, yet effective treatment options remain limited. Through integrative analysis of single-cell RNA-seq data from intervertebral discs (IVDs), we have firstly uncovered that the aberrant accumulation of R-Loops—a type of triple-stranded nucleic acid structure—can result in the cytoplasmic accumulation of double-stranded DNA (dsDNA) and activate cGAS/STING signaling and induce cellular senescence in nucleus pulposus cells (NPCs) during IVDD. Restoring the R-Loop state significantly mitigated both the activation of the cGAS/STING pathway and NPC senescence. Additionally, we identified ERCC5 as a critical regulator of the R-Loop state and cellular senescence. Thus, we developed an NPC-targeting nano-delivery platform (CTP-PEG-PAMAM) to deliver si-Ercc5 to the NP region of the IVDD. This approach aims to modulate the abnormal R-Loop state and inhibit the activation of cGAS/STING signaling in NPCs for IVDD treatment. CTP-PEG-PAMAM demonstrated excellent targeting capability towards NPCs and NP tissue, and achieved effective silencing of the Ercc5 gene without causing systemic organ complications. Both in vitro and in vivo experiments revealed that CTP-PEG-PAMAM-siERCC5 significantly inhibited cGAS/STING signaling activated by aberrant R-Loops, alleviated cellular senescence and promoting cell proliferation, thereby delayed IVDD in a puncture-induced rat model. In conclusion, the ERCC5-R-Loop-cGAS/STING axis in NPCs represents a promising therapeutic target for delaying IVDD, and the designed CTP-PEG-PAMAM/siRNA complex holds great potential for clinical application in the treatment of IVDD. Targeted inhibition of cGAS/STING signaling induced by aberrant R-loops in the nucleus pulposus to alleviate cellular senescence and intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) has been a complex disorder resulted from genetic and environmental risk factors. The aim of this study was to identify the risk factors associated with IVDD in orthopaedic patients and develop a prediction model for predicting the risk of IVDD. A total of 309 patients were retrospectively included in the study and randomly divided into the training group and the validation group. The least absolute shrinkage and selection operator regression (LASSO) and the univariate logistic regression analysis were used to optimize factors selection for the IVDD risk model. Multivariable logistic regression analysis was used to establish a predicting nomogram model incorporating the factors. In addition, discrimination, calibration, and clinical usefulness of the nomogram model were evaluated via the C-index, receiver operating characteristic (ROC) curve, calibration plot, and decision curve analysis (DCA). Then, based on the results above, the relationship between IVDD and angiotensin II (AngII) level in peripheral blood was examined prospectively. The predictors of the nomogram include age, sex, hypertension, diabetes, gout, working posture, and exercising hours per week. The C -index values of the training and validation groups were 0.916 (95% CI, 0.876-0.956) and 0.949 (95% CI, 0.909-0.989), respectively, which indicated that the model displayed good discrimination. In addition, the area under the curve (AUC) values of the ROC curve of the training and the validation group were 0.815 (95% CI, 0.759-0.870) and 0.805 (95% CI, 0.718-0.892), respectively, revealing the satisfactory discrimination performance of the model. The prospective investigation showed that the average AngII level in the degenerated group ( 97.62 ± 44.02 pg/mL) was significantly higher than that in the nondegenerated group ( 52.91 ± 9.01 pg/mL) ( p < 0.001 ). This present study explored the risk factors for IVDD and established a prediction model, which would effectively predict the risk of IVDD. In addition, based on the prediction model, AngII was revealed to be a potentially auxiliary clinical diagnostic marker for IVDD.

Background: Anterior cervical controllable antedisplacement and fusion (ACAF) is utilized for the treatment of symptomatic ossification of the posterior longitudinal ligament (OPLL). The aims of the procedure are to directly relieve ventral compression of the spinal cord, to reconstruct the spinal canal and restore cervical alignment, and to achieve satisfactory clinical recovery. Description: The detailed steps to perform ACAF have been described previously ¹ . Briefly, following induction of general endotracheal anesthesia, a standard right- or left-sided Smith-Robinson incision is made. Discectomies are performed at the involved levels. By measuring the thickness of the OPLL on an axial preoperative computed tomography scan at each compressed level, the amount of each anterior vertebral body to be resected can be calculated preoperatively. This was, in general, equal to the thickness of the ossified mass at the same level. The previously calculated portion of each involved body in the vertebral body-OPLL complex is resected. Following the creation of a contralateral longitudinal osseous trough, the prebent anterior cervical plate is then placed, and the screws are installed after proper drilling and taping on the remaining vertebral bodies. The screws utilized in this procedure should not be too short to achieve adequate purchase in the vertebral body. Subsequently, the intervertebral cages are inserted. Thus, the vertebral body-OPLL complex is temporarily stabilized for the next procedure. Next, an ipsilateral longitudinal osseous trough is created to completely isolate the vertebral body-OPLL complex. Notably, the objective of complete isolation of the vertebral body-OPLL complex is to further anteriorly hoist the complex to decompress the spinal cord. Finally, screws are inserted through the plate and into each vertebral body and are gradually tightened to displace the bodies anteriorly. Allogenic iliac bone graft is placed in the longitudinal bone troughs to promote fusion. Alternatives: Nonoperative treatment is frequently ineffective. Traditional surgical interventions have included anterior cervical corpectomy and fusion (ACCF), posterior laminoplasty, and laminectomy ^2,3 . ACCF focuses on resecting the ventral ossified mass in order to obtain direct decompression; however, this technique is very technically demanding, with a high risk of complications. In addition, the clinical benefits of ACCF will be limited when the OPLL extends over >3 levels. Posterior decompression can achieve indirect decompression by allowing the spinal cord to float away from the ossified mass. This technique depends largely on the preoperative presence of cervical lordosis and is contraindicated in patients with kyphosis or severe OPLL. In addition, posterior decompression surgery has been associated with a high incidence of late neurological deterioration and even revision surgery ² . Rationale: ACAF combines the advantages of direct decompression as occurs with ACCF with the limited manipulation of the canal contents as occurs with the posterior approach ^4–6 . The procedure considers the ossified mass and the vertebral body as a single unit. Decompression is accomplished by moving the vertebral body with the OPLL ventrally away from the spinal cord. The preserved part of the vertebral body-OPLL complex becomes part of the anterior wall of the spinal canal. Without direct instrument manipulation inside the canal, the occurrence of cerebrospinal fluid leakage, hemorrhage, and intraoperative neural injury can be minimized ⁵ . Compared with a posterior approach, ACAF can achieve more decompression of the cord, especially in patients with cervical kyphosis and those with >60% of the spinal canal occluded ⁶ . Expected Outcomes: This procedure can yield satisfactory clinical outcomes with fewer surgery-related complications ^1,4–6,9 . A single-center, prospective, randomized controlled study showed significantly better Japanese Orthopaedic Association scores and recovery rates at 1 year for ACAF compared with laminoplasty for the treatment of multilevel OPLL in cases in which the occupying ratio of the canal was >60% occluded or the K-line (i.e., a virtual line between the midpoints of the anteroposterior canal diameter at C2 and C7) was negative ⁹ . In addition, patients who underwent ACAF had better preservation of cervical lordosis and sagittal balance ⁹ . Important Tips: The cervical segments to be treated should include all of the segments with OPLL that are causing spinal cord compression. The uncinate process can be utilized as a safe anatomical landmark for the longitudinal osteotomies in order to avoid vertebral artery injury, even in cases with severely ossified masses. Careful evaluation of the vertebral artery on preoperative magnetic resonance imaging or computed tomography is of great importance. Appropriately increasing the curvature of the cervical plate can further enlarge the space for the following antedisplacement of the vertebral body-OPLL complex. The location of the uncinate processes must be confirmed before the creation of the 2 longitudinal osseous troughs ^7,8 . The preserved superior and inferior vertebral end plates should be made as smooth and mutually parallel as possible. The thickness of the anterior part of the vertebral bodies to be resected should be calculated preoperatively. The posterior longitudinal ligament behind the involved segments should not be resected. Acronyms and Abbreviations: ACAF = anterior cervical controllable antedisplacement and fusion ACCF = anterior cervical corpectomy and fusion OPLL = ossification of the posterior longitudinal ligament CT = computed tomography JOA = Japanese Orthopaedic Association MRI = magnetic resonance imaging OR = occupying rate of the spinal canal VOC = vertebral bodies-OPLL complex RR = recovery rate CSF = cerebrospinal fluid UP = uncinate process TF = transverse foramen

Chronic low back pain (CLBP) has been proved to be the dominating cause of disability in patients with lumbar degenerative diseases. Of the various etiological factors, intervertebral disc degeneration (IVDD) has been the dominating cause. In the past few decades, the role and changes of nerve systems, especially the peripheral sensory fibers and their neurotransmitters, in the induction and progression of IVDD have attracted growing concerns. The expression of many neuropeptides, such as SP, NPY, and CGRP, in the nociceptive pathways is increased during the progression of IVDD and responsible for the discogenic pain. Here, the role of CGRP in the progression of IVDD was firstly investigated both in vitro and in vivo. Firstly, we confirmed that human degenerated intervertebral disc tissue exhibited elevated expression of CGRP and its receptor. Secondly, in vitro experiments suggested that CGRP could inhibit the proliferation and induce apoptosis in human nucleus pulposus (NP) cells, as well as promote inflammation and degenerated phenotypes through activating NF‐κB and MAPK signaling pathways. Thirdly, CGRP receptor antagonist, Rimegepant, can ameliorate the adverse effects of CGRP imposed on NP cells, which were confirmed in vitro and in vivo. Our results will bring about a brand‐new insight into the roles of neuromodulation in IVDD and related therapeutic attempts.

Objective To propose a novel technique of free‐hand pedicle screw placement in cervicothoracic spine (snake‐eye method) and evaluate the preliminary effects and safety in clinical practice. Methods This is a retrospective study and we defined the period of this study as from December 2017 to April 2019 in our institution. Forty patients were included in this study who underwent cervicothoracic internal fixation in our hospital, and all patients undergoing implantation of 200 pedicle screws were divided into two groups. Twenty‐two patients (108 screws) had screw placement using traditional method, while 18 patients (92 screws) had screw placement using snake‐eye method. To reduce the possible selection bias, the patients we recruited in this study was originally performed on by one radiological doctor who was blind to the objective of this study. Patient demographics, including patient age, sex, obesity, smoking, and hypertension, were evaluated to figure out baseline differences between groups. Medical information was recorded including time, accuracy, and immediate (within 30 days after surgery) postoperative complications of pedicle screw placement (including pulmonary embolism or other thromboembolic events, surgical site infection, neurovascular injury, and mortality). Results There were 24 males and 16 females, with an average age of 52.2 years (range, 24–77). Finally, a total of 200 screws were successfully inserted in these patients, including fifteen patients with four pedicle screws, four patients with six screws, three patients with eight screws in traditional method group, and 12 patients with four pedicle screws, two patients with six screws, four patients with eight screws in snake‐eye method group. Patient demographic and comparison of two surgery methods are shown in Tables 1 and 2. The data baselines of the two groups were comparable because no impact of the two groups on population characteristics was demonstrated in the presented experiment. Also, we noticed that time and accuracy of the two groups were different with statistical significance at the level of P = 0.05. We observed that immediate (within 30 days after surgery) postoperative complications, including pulmonary embolism (PE), surgical site infection (SSI), neurovascular injury (NI), and mortality, in the two groups did not differ. Conclusion This study highlights a safe and effective technique for pedicle screw placement in cervicothoracic spine named snake‐eye method, and this technique may be particularly useful in emergency conditions with limited resources.

The average time myosin cross bridges remain bound to actin ( t_on) can be measured by sinusoidal length perturbations (sinusoidal analysis) of striated muscle fibers using recently developed analytic methods. This approach allows measurements of t_on in preparations possessing a physiologically relevant myofilament lattice. In this study, we developed an approach to measure t_on in 5–10% of the time required for sinusoidal analysis by using stochastic length perturbations (white noise analysis). To compare these methods, we measured the influence of MgATP concentration ([MgATP]) on t_on in demembranated myocardial strips from mice, sampling muscle behavior from 0.125 to 200 Hz with a 20-s burst of white noise vs. a 300-s series of sinusoids. Both methods detected a similar >300% increase in t_on as [MgATP] decreased from 5 to 0.25 mM, differing by only 3–14% at any [MgATP]. Additional experiments with Drosophila indirect flight muscle fibers demonstrated that faster cross-bridge cycling kinetics permit further reducing of the perturbation time required to measure t_on. This reduced sampling time allowed strain-dependent measurements of t_on in flight muscle fibers by combining 10-s bursts of white noise during periods of linear shortening and lengthening. Analyses revealed longer t_on values during shortening and shorter t_on values during lengthening. This asymmetry may provide a mechanism that contributes to oscillatory energy transfer between the flight muscles and thoracic cuticle to power flight. This study demonstrates that white noise analysis can detect underlying molecular processes associated with dynamic muscle contraction comparable to sinusoidal analysis, but in a fraction of the time.