N6-methyladenosine (m6A) methylation, the most prevalent internal mRNA modification in eukaryotes, plays a crucial role in regulating various biological processes. Recent advancements reveal its significant involvement in osteoarthritis (OA) and intervertebral disc degeneration (IVDD). m6A modifications influence key cellular processes such as inflammation, stress responses, and matrix homeostasis, which are pivotal in OA and IVDD pathogenesis. In OA, m6A methylation affects inflammatory responses, macrophage polarization, and chondrocyte ferroptosis, while in IVDD, it regulates RNA methylation and matrix integrity. Additionally, m6A interacts with noncoding RNAs, impacting their stability and function, thus influencing disease outcomes. Emerging evidence suggests that targeting m6A pathways could provide novel therapeutic strategies for managing OA and IVDD. Further research into m6A's role in these diseases may reveal new biomarkers and therapeutic targets, offering potential for more effective treatments and improved patient outcomes.

Wearable inertial sensors enable continuous and accurate monitoring of movement posture during rehabilitation training. However, challenges remain in posture estimation accuracy due to sensor placement bias, environmental interference, and the complexity introduced by nonlinear calibration models and multi-sensor data fusion. In this study, our previously proposed inclination-based linear magnetometer calibration model was validated through laboratory experiments involving dynamic indoor movements. Results demonstrate that the model effectively calibrates magnetometers without axes aligned, as verified by a motion capture system, leading to significantly improved flexibility and accuracy, as well as reduced workload and complexity in lower limb movement evaluation. Following laboratory validation, the calibrated sensor network is deployed in clinical settings for assessing lower limb function in patients with hemiplegia. The proposed calibration method and sensor network are empirically evaluated to provide a robust theoretical and technical foundation for clinical application. By establishing a reliable posture evaluation network tailored for rehabilitation training and potential for home monitoring, this study offers innovative calibration strategies and practical solutions that support the optimization of rehabilitation assessment and treatment, contributing to the advancement of intelligent rehabilitation medicine.

Nucleus pulposus (NP) cell senescence is a critical factor in the progression of intervertebral disc degeneration (IVDD). Our analysis demonstrates that FTO and YAP1 expression levels are significantly diminished in degenerative NP tissues from both human and rat models, which correlates with increased m6A modification of YAP1 transcripts. To investigate the underlying mechanisms, we utilized IL-1β to induce senescence in cultured NP cells. Our findings reveal that FTO knockdown leads to a decrease in YAP1 levels while simultaneously increasing senescence markers. In contrast, the overexpression of YAP1 alleviates the senescence phenotype in FTO-deficient cells, underscoring the protective role of YAP1 in NP cells. This study proposes a novel regulatory pathway in which FTO modulates YAP1 through m6A demethylation, suggesting potential therapeutic targets for mitigating NP cell senescence and IVDD.

To investigate potential risk factors for osteoporotic vertebral compression re-fractures (OVCRFs) following percutaneous kyphoplasty (PKP). Patients who underwent PKP from January 2012 to January 2020 were included in this study within the same institution. Cases were defined as patients who experienced OVCRFs, while controls were matched based on corresponding clinical characteristics from those patients without OVCRFs. The lumbar localized fat distribution parameters, including the fat infiltration ratio (FIR) in muscles [multifidus (MF), erector spinae (ES), paravertebral muscles (PVM), and psoas major (PS)] and subcutaneous fat thickness (SFT), were compared between the two groups through radiological data. And other clinical data that may be relevant were also compared. Independent risk factors for OVCRFs after PKP were identified through a binary logistic regression analysis. A total of 1391 patients who underwent PKP were included in this study. 51 patients were categorized into the re-fracture group, and 102 patients were selected as matched controls from the remaining cohort. There were statistically significant differences between the two groups in metrics including MF-FIR, ES-FIR, PVM-FIR, PS-FIR, bone mineral density (BMD), body-mass index (BMI), SFT, hemoglobin (Hb), albumin (ALB), alkaline phosphatase (ALP), and triglycerides (TG) (P < 0.05). Binary logistic regression analysis demonstrated that PVM-FIR (P = 0.003), SFT (P < 0.001), BMD (P = 0.011), and ALP (P = 0.005) were independent predictors for the occurrence of OVCRFs. This study discovered that lumbar localized fat distribution parameters including PVM-FIR and SFT are independent predictors of OVCRFs. Additionally, BMD and ALP were found to be independent predictors of OVCRFs.

Osteoporotic vertebral compression fractures (OVCF) cascades (OVCFcs) repeatedly cause vertebral compression to involve multiple vertebra. This study aimed to introduce an accelerated form of OVCFcs: acute multiple OVCF (amOVCF). OVCF patients with multiple vertebral augmentations in a spine center between June 2016 and October 2020 were retrospectively studied. Demographics, spine trauma, anatomical distribution, and distribution pattern of OVCF in OVCFcs and amOVCF were summarized and compared. 429 patients with multiple vertebral augmentations in 1164 vertebra were included. There were 210 OVCFcs accumulating 622 OVCF and 219 amOVCF simultaneously involving 542 vertebra. The OVCFcs progressed at 0.48 fractures and 0.56 vertebra per year. Both OVCFcs and amOVCF demonstrated asymmetrical bimodal distribution in spine and most frequently involved L1. The incidence of adjacent OVCF was 40.14

Abstract Background Cellular senescence features irreversible growth arrest and secretion of multiple proinflammatory cytokines. Cyclic GMP-AMP synthase (cGAS) detects DNA damage and activates the DNA-sensing pathway, resulting in the upregulation of inflammatory genes and induction of cellular senescence. This study aimed to investigate the effect of cGAS in regulating senescence of nucleus pulposus (NP) cells under inflammatory microenvironment. Methods The expression of cGAS was evaluated by immunohistochemical staining in rat intervertebral disc (IVD) degeneration model induced by annulus stabbing. NP cells were harvested from rat lumbar IVD and cultured with 10ng/ml IL-1β for 48 h to induce premature senescence. cGAS was silenced by cGAS specific siRNA in NP cells and cultured with IL-1β. Cellular senescence was evaluated by senescence-associated beta-galactosidase (SA-β-gal) staining and flow cytometry. The expression of senescence-associated secretory phenotype including IL-6, IL-8, and TNF-a was evaluated by ELISA and western blotting. Results cGAS was detected in rat NP cells in cytoplasm and the expression was significantly increased in degenerated IVD. Culturing in 10ng/ml IL-1β for 48 h induced cellular senescence in NP cells with attenuation of G1-S phase transition. In senescent NP cells the expression of cGAS, p53, p16, NF-kB, IL-6, IL-8, TNF-α was significantly increased while aggrecan and collagen type II was reduced than in normal NP cells. In NP cells with silenced cGAS, the expression of p53, p16, NF-kB, IL-6, IL-8, and TNF-α was reduced in inflammatory culturing with IL-1β. Conclusion cGAS was increased by NP cells in degenerated IVD promoting cellular senescence and senescent inflammatory phenotypes. Targeting cGAS may alleviate IVD degeneration by reducing NP cell senescence.

Abstract Background Osteoporotic vertebral compression fractures (OVCF) are common in aged population with bone fragility. This study aimed to identify the radiographic and bone fragility characteristic of acute single and multiple OVCF. Methods OVCF patients hospitalized in a spine center between June 2016 and October 2020 were retrospectively studied. Demographics, comorbidity, bone mineral density, spine trauma, duration of pre-hospital back pain, anatomical location and distribution pattern of OVCF, extent of vertebral marrow edema, and degree of vertebral compression of patients with multi-segment vertebral fractures (MSVF) were summarized and compared to those with single segment vertebral fractures (SSVF). Results A total of 1182 patients with 1530 acute fractured vertebrae were included. There were 944 SSVF (79.9%) and 238 MSVF (20.1%) simultaneously involving two (MSVF-2) or three and more vertebra (MSVF-3/m). The Female-Male ratio was 4.4 and differed not significantly between SSVF and MSVF. Females in SSVF were younger than males while MSVF-2 tended to occur in older females. L1, T12, and L2 were the three most frequently fractured vertebra and MSVF involved more vertebra in thoracic and lumbar spine. 31.1% in MSVF-2 and 83.1% in MSVF-3/m had at least two vertebral fractures in adjacent. The fractured thoracolumbar vertebra in MSVF was less compressed than that in SSVF. Apparent spine trauma was reported by 61.4% of SSVF, 44.1% of MSVF-2, and 36.3% of MSVF-3/m, while early hospitalization with pre-hospital back pain ≤ 1 week was 58.9% in SSVF, 45.3% in MSVF-2, and 25.9% in MSVF-3/m. Only females aged 70–80 years old in MSVF-3/m showed lower baseline bone mineral density than in MSVF-2 and SSVF. MSVF were not associated with increased comorbidity of hypertension, diabetes, coronary heart disease, cerebral infarction, and chronic pulmonary disease. Conclusions 20% of acute OVCF can involve multiple vertebra without significant spine trauma or lower baseline bone mineral density. Multiple OVCF tend to occur in adjacent vertebra with less thoracolumbar vertebral compression but longer duration of pre-hospital back pain.

Dietary omega-3 polyunsaturated fatty acids (ω-3 PUFAs) can be classified into animal- and plant-derived ω-3 PUFAs. Patients with type 2 diabetes (T2DM) are frequently accompanied by dyslipidemia, which is closely related to the high-density lipoprotein (HDL-C) subfractions change. This study aimed to determine the effects of different sources ω-3 PUFAs on glucolipid metabolism and lipoprotein subfractions in T2DM with dyslipidemia. Ninety T2DM patients with dyslipidemia were randomly assigned to take 3 g/day fish oil (FO, containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), 3 g/day perilla oil (PO, containing α-linolenic acid (ALA)), or 3 g/day blend oil (BO, containing EPA, DHA and ALA) for 3 months. 90 patients completed the intervention. There was a significant reduction of glycated hemoglobin (HbA1c) in all the groups. The triglycerides (TG) in the FO group were significantly different with a group × time interaction (P = 0.043), which was higher compared with the other two groups. The serum small HDL-C subfractions in the PO group was higher and the serum large HDL-C subfractions in the PO group was lower than those in the BO and FO groups. Plant-derived ω-3 PUFAs are more effective at controlling blood glucose than animal-derived ω-3 PUFAs. However, animal-derived ω-3 PUFAs have a significant lowering effect on TG compared with plant-derived ω-3 PUFAs. Particularly, large HDL-C subfractions after animal-derived ω-3 PUFAs intake were higher than plant-derived ω-3 PUFAs intake; while small HDL-C subfractions were lower. Both the animal- and plant-derived ω-3 PUFAs have practical value in improving glucose and lipids metabolism in T2DM patients with dyslipidemia.

BACKGROUND:The pathological mechanism of intervertebral disc degeneration (IDD) is an unanswered question that we are committed to exploring. A20 is an anti-inflammatory protein of nucleus pulposus (NP) cells and plays a protective role in intervertebral disc degeneration.OBJECTIVE:This study aims to investigate the molecular mechanism by which A20 attenuates disc degeneration.METHODS:The proteins of interest were measured by immunoblotting, immunofluorescence, ELISA assay, and immunohistochemical technique to conduct related experiments. Immunofluorescence assays and mitochondrial membrane potential (JC-1) were used to assess mitophagy and mitochondrial fitness, respectively.RESULTS:Here, we demonstrated that A20 promoted mitophagy, attenuated pyroptosis, and inhibited the degradation of the extracellular matrix, consequently significantly ameliorating disc degeneration. Mechanistically, A20 reduces pyroptosis and further suppresses cellular mTOR activity. On the one hand, A20-induced mTOR inhibition triggers BNIP3-mediated mitophagy to ensure mitochondrial fitness under LPS stimulation, as a result of mitigating mitochondrial dysfunction induced by LPS. On the other hand, A20-induced mTOR inhibition reduces the loss of mitochondrial membrane potential and the generation of Mitochondrial ROS.CONCLUSION:The study revealed that A20 promotes BNIP3-mediated mitophagy by suppressing mTOR pathway activation against LPS-induced pyroptosis.

PURPOSE:Intervertebral disc degeneration is an abnormal, cell-mediated process of tissue remodeling, recognized as the principal cause of low back pain affecting 80% of the population worldwide. Inflammatory cytokine, Interleukin-1beta (IL-1β) is involved in the intervertebral disc degeneration (IDD) process, and it is upregulated in degenerated discs. Omentin-1, also known as intelectin-1, is an adipokine with anti-inflammatory, anti-apoptosis, pro-proliferation, and proangiogenic properties in various types of cells. However, little is known about the effects of omentin-1 on human nucleus pulposus cells (HNPCs). This study aims to investigate the effects of omentin-1 on healthy HNPCs regarding proliferation and further investigate the effects of omentin-1 on IL-1β-induced inflammation, apoptosis, and degeneration in HNPCs. METHODS:Genes and proteins of interest were measured by qRT-PCR, immunoblotting, and immunofluorescence to conduct related experiments. Cell viability (CCK-8), EdU, and mitochondrial membrane potential (JC-1), flow cytometry assays were used to assess proliferation and apoptosis, respectively. RESULTS:Our study showed that omentin-1 promoted proliferation in normal HNPCs. Furthermore, omentin-1 expression was decreased in IL-1β-treated HNPCs. Omentin-1 protected against IL-1β-induced inflammation, apoptosis, and degeneration in HNPCs in vitro via the activation of the PI3K/Akt signaling pathway. CONCLUSION:These findings may contribute to understanding the role of omentin-1 in HNPCs and may be a potential therapeutic candidate for intervertebral disc degeneration.

Abstract Objective To investigate the clinical results of transforaminal endoscopic lumbar discectomy for lumbosacral junction adolescent lumbar disc herniation with high iliac crest. Methods From February 2014 to September 2020, a retrospective analysis of 96 patients less than 21 years old with intervertebral disc herniation was carried out. We enrolled 44 patients diagnosed with lumbosacral junction disc herniation with high iliac crest who required transforaminal endoscopic lumbar discectomy. Pain in the back and the lower extremity was scored on Numeric Rating Scales (NRS) scores. Patient outcomes were graded as excellent, good, fair, and poor using modified MacNab criteria. The NRS scores before and after the operation were compared using the Wilcoxon two‐sample test. Results There were 30 male patients and 14 females. One patient underwent repeat surgery for an intervertebral disc pseudocyst. The NRS scores decreased significantly in both early and late follow‐up evaluations (p < 0.05). At the last follow‐up, 42 patients (95.45%) had an excellent outcome, one patient (2.27%) had a good outcome, and one patient (2.27%) had a fair outcome. The overall success rate was 97.7%. Conclusion This study's data suggest that targeted individualized foraminoplasty can effectively overcome the lumbosacral anatomical obstacles, and transforaminal endoscopic lumbar discectomy is an effective and valid option for lumbosacral junction adolescent lumbar disc herniation with high iliac crest.

Low back pain (LBP) is a common disorder in orthopedic outpatients, affecting people of all ages, and some patients may develop chronic LBP. As a complex organelle, mitochondria are not only energy workstations but also regulate cell senescence, apoptosis, and homeostasis. Mitochondrial dysfunction promotes disk degeneration by affecting a variety of pathophysiological processes, including oxidative stress, mitophagy, mitochondrial homeostasis, cellular senescence, and cell death. We review the molecular mechanisms underlying the relationship between mitochondrial dysfunction and intervertebral disk degeneration (IDD) to provide a theoretical basis for IDD treatment using pharmacological or tissue-engineering approaches.

Most readout circuits of the two-dimensional resistive sensor array (2-D RSA) have a non-linear relationship between the output voltage and the resistance of the element being tested (EBT), which will cause extra measurement error for the finite precision of the analog-to-digital converter. Firstly, we designed a novel linear readout circuit based on double voltage feedback loops (LRC-DVFL) which could access two elements in the array simultaneously, and the output voltages had a linear relationship with the resistances of the EBTs. Then, the approximate circuit model of the LRC-DVFL was derived and the mathematical equivalent resistance expressions of the EBTs were derived in Appendix. Followed, the simulation experiments and the test experiments with a prototype circuit of the LRC-DVFL were carried out. Experimental results show that the LRC-DVFL can access two elements in the 2-D RSA simultaneously with linear output voltages, and the performance of the LRC-DVFL can be evaluated quickly by using the mathematical equivalent resistance expressions of the EBTs.

目的 提取EEG的小波特征和EMG的时域、频域、时频域以及样本熵等多种特征进行分析,对人体下肢运动识别进行研究.方法 采集人体站立、行走、上楼梯、下楼梯、上坡和下坡6种下肢运动模式的脑电、肌电信号,并对信号进行预处理、特征提取和模式识别,解析人体下肢运动的意图和具体的下肢运动类型.结果 从时域、频域、时频域和时序复杂度等维度上提取的信号特征能够较好的表征信号;基于支持向量机的脑电信号分类方法对下肢有无运动意图的平均识别率达到93.2％;基于极端梯度提升的肌电信号分类方法对下肢六种运动模式的平均识别率达到93.6％.结论 本文提出的方法能够有效的对人体下肢运动进行识别,准确地识别到人体下肢运动意图,可以为下肢外骨骼机器人提供精准安全的控制策略,提高下肢外骨骼机器人助行助力的效率.

目的 利用影像组学与集成学习进行肝脏脂肪变性分级研究.方法 回顾性分析2018年6月至8月于上海市第一人民医院进行MR上腹部mDixon成像序列扫描的成人患者资料,将患者的MRI数据利用影像组学特征提取方法和机器学习进行建模,研究采用3项指标对三种集成学习分类算法(AdaBoost、GBDT与XGBoost)的性能进行评估,包括准确率、精确率、召回率.结果 XGBoost算法性能最佳,分类准确率达到81.9％;五项特征重要性之和大于19％,即在总体肝脏脂肪变形程度轻中度分类模型之中所占权重接近1/5.结论 影像组学与集成学习方法为脂肪变性分级提供了一种较为可靠的辅助诊断手段,对轻中度脂肪变性的研究也能够为患者脂质代谢相关疾病的临床干预或治疗时机提供一定的参考价值.

目的 结合深度学习和迁移学习,研究肝脂肪变性分级,为肝脂肪变性分级提供一种智能的无创性思路.方法 收集上海交通大学附属第一人民医院2018年6月至7月的50例进行上腹部mDixon成像序列扫描患者的MR影像资料,选取感兴趣区域并进行数据增强和不平衡数据处理.建立DenseNet模型并进行预训练,数据集输入模型进行模型调整,最终得出肝脂肪变性等级.同时对患者临床信息与肝脂肪变性等级进行相关性分析.结果 DenseNet模型验证集AUC为0.83,精确度为84.96％,敏感度和特异度分别达到94.55％和79.82％.结论 基于深度学习的肝脂肪变性分级具有性能良好、自动化分级的优势,相关性分析为肝脂肪变性等级及其相关因素的研究提供了思路.

Abstract Background The beneficial effects of ω−3 polyunsaturated fatty acids (PUFA) vary between different sources. However, there is a paucity of comparative studies regarding the effects and mechanisms of marine and plant ω−3 PUFA on obesity. Objective The aim of this study was to evaluate the effects of fish oil (FO) and perilla oil (PO) on glucolipid metabolism, inflammation, and adipokine in mice fed a high-fat (HF) diet in association with the contribution of toll-like receptor 4 (TLR4)/myeloid differentiation primary response 88 (MyD88) pathway. Methods C57BL/6J mice and MyD88−/− mice were randomly divided into 4 groups: normal chow diet, HF diet, HF diet accompanied by daily gavage with either FO or PO. After 4 weeks, blood biochemistries, adipocyte histology, mRNA, and protein expression of MyD88-dependent and -independent pathways of TLR4 signaling in epididymal adipose tissue were measured. Results In C57BL/6J mice, there were no statistical differences between FO and PO in decreasing body weight, glucose, insulin, triglyceride, total cholesterol, interleukin-6, and increasing adipocyte counts. FO and PO decreased mRNA and protein expression of TLR4, MyD88, tumor necrosis factor receptor-associated factor 6, inhibitor of nuclear factor kappa B kinase beta and nuclear factor-kappa B p65. In MyD88−/− mice, the beneficial effects of FO and PO on HF diet-induced metabolism abnormalities and inflammation were abolished. FO and PO had no impacts on mRNA and protein expression of receptor-interacting protein-1, interferon regulate factor 3, and nuclear factor-kappa B p65. Conclusion FO and PO exhibit similar protective effects on metabolic disorders and inflammation through inhibiting TLR4 signaling in a manner dependent on MyD88. These findings highlight plant ω−3 PUFA as an attractive alternative source of marine ω−3 PUFA and reveal a mechanistic insight for preventive benefits of ω−3 PUFA in obesity and related metabolic diseases.

The background of abdominal computed tomography (CT) images is complex, and kidney tumors have different shapes, sizes and unclear edges. Consequently, the segmentation methods applying to the whole CT images are often unable to effectively segment the kidney tumors. To solve these problems, this paper proposes a multi-scale network based on cascaded 3D U-Net and DeepLabV3+ for kidney tumor segmentation, which uses atrous convolution feature pyramid to adaptively control receptive field. Through the fusion of high-level and low-level features, the segmented edges of large tumors and the segmentation accuracies of small tumors are effectively improved. A total of 210 CT data published by Kits2019 were used for five-fold cross validation, and 30 CT volume data collected from Suzhou Science and Technology Town Hospital were independently tested by trained segmentation models. The results of five-fold cross validation experiments showed that the Dice coefficient, sensitivity and precision were 0.796 2 ± 0.274 1, 0.824 5 ± 0.276 3, and 0.805 1 ± 0.284 0, respectively. On the external test set, the Dice coefficient, sensitivity and precision were 0.817 2 ± 0.110 0, 0.829 6 ± 0.150 7, and 0.831 8 ± 0.116 8, respectively. The results show a great improvement in the segmentation accuracy compared with other semantic segmentation methods.

Background: The critical role of phosphoinositide 3-kinase (PI3K) activation in tumor cell biology has prompted massive efforts to develop PI3K inhibitors (PI3Kis) for cancer therapy. However, recent results from clinical trials have shown only a modest therapeutic e�cacy of single-agent PI3Kis in solid tumors. Targeting autophagy has controversial context-dependent effects in cancer treatment. As a FDA-approved lysosomotropic agent, hydroxychloroquine (HCQ) has been well tested as an autophagy inhibitor in preclinical models. Here, we elucidated the novel mechanism of HCQ alone or in combination with PI3Ki BKM120 in the treatment of cancer. Methods: The antitumor effects of HCQ and BKM120 on three different types of tumor cells were assessed by in vitro PrestoBlue assay, colony formation assay and in vivo zebra�sh and nude mouse xenograft models. The involved molecular mechanisms were investigated by MDC staining, LC3 puncta formation assay, immuno�uorescent assay, �ow cytometric analysis of apoptosis and ROS, qRT-PCR, Western blot, comet assay, homologous recombination (HR) assay and immunohistochemical staining. Results: HCQ signi�cantly sensitized cancer cells to BKM120 in vitro and in vivo. Interestingly, the sensitization mediated by HCQ could not be phenocopied by treatment with other autophagy inhibitors (Spautin-1, 3-MA and ba�lomycin A1) or knockdown of the essential autophagy genes Atg5/Atg7, suggesting that the sensitizing effect might be mediated independent of autophagy status. Mechanistically, HCQ induced ROS production and activated the transcription factor NRF2. In contrast, BKM120 prevented the elimination of ROS by inactivation of NRF2, leading to accumulation of DNA damage. In addition, HCQ activated ATM to enhance HR repair, a high-�delity repair for DNA double-strand breaks (DSBs) in cells, while BKM120 inhibited HR repair by blocking the phosphorylation of ATM and the expression of BRCA1/2 and Rad51. Conclusions: Our study revealed that HCQ and BKM120 synergistically increased DSBs in tumor cells and therefore augmented apoptosis, resulting in enhanced antitumor e�cacy. Our �ndings provide a new insight into how HCQ exhibits antitumor e�cacy and synergizes with PI3Ki BKM120, and warn that one should consider the “off target” effects of HCQ when used as autophagy inhibitor in the clinical treatment of cancer.

Yes-associated protein (YAP) activity responded to physical and mechanical cues such as extracellular matrix (ECM), cell density and the mechanical regulation of YAP controlled cellular proliferation and inhibition of apoptotic signals. The intervertebral disc (IVD) comprises a heterogeneous population of cells, including those of the nucleus pulposus (NP) and annulus fibrosus (AF), which are diverse in phenotype, partly due to the different ECM and mechanical loads they experience. How do IVD cells sense microenvironment and what is the relationship between YAP and cytoskeleton in the process of intervertebral disc degeneration (IDD) are not well understood. First, Hippo pathway and cytoskeleton organisation were assessed in the NP and AF of immature (4 weeks), mature (14 weeks), aged (50 weeks), and degenerated (14 weeks, 4 weeks after annulus puncture) IVDs. Second, to assess the effect of ECM composition and cell density on cytoskeleton and YAP levels, we seeded cells at different densities on three types of ECM. In this study, YAP and F-actin activity decreased gradually with age in natural IDD. Hippo signalling was suppressed in the early stages of disc injury, demonstrating the potential for endogenous repair, but this repair did not prevent further disc degeneration. β-tubulin and vimentin filaments provide the cell with its shape and its elastic properties in resisting mechanical forces. The Hippo pathway and cytoskeleton were shown to be regulated by cell density and the ECM composition.