Dysfunction of STING Autophagy Degradation in Senescent Nucleus Pulposus Cells Accelerates Intervertebral Disc Degeneration.

The pathogenesis of Intervertebral Disc Degeneration (IDD) is complex and multifactorial, with cellular senescence of nucleus pulposus (NP) cells and inflammation playing major roles in the progression of IDD. The stimulator of interferon genes (STING) axis is a key mediator of inflammation during infection, cellular stress, and tissue damage. Here, we present a progressive increase in STING in senescent NP cells with the degradation disorder. The STING degradation function in normal NP cells can prevent IDD. However, the dysfunction of STING degradation through autophagy causes the accumulation and high expression of STING in senescent NP cells as well as inflammation continuous activation together significantly promotes IDD. In senescent NP cells and intervertebral discs (IVDs), we found that STING autophagy degradation was significantly lower than that of normal NP cells and IVDs when STING was activated by 2'3'-cGAMP. Also, the above phenomenon was found in STINGgt/gt, cGAS-/- mice with models of age-induced, lumbar instability-induced IDD as well as found in the rat caudal IVD puncture models. Taken together, we suggested that the promotion of STING autophagy degradation in senescent NP Cells demonstrated a potential therapeutic modality for the treatment of IDD.

Loss of DDRGK1 impairs IRE1α UFMylation in spondyloepiphyseal dysplasia.

Spondyloepiphyseal dysplasia (SEMD) is a rare disease in which cartilage growth is disrupted, and the DDRGK1 mutation is one of the causative genes. In our study, we established Ddrgk1fl/fl, Col2a1-ERT Cre mice, which showed a thickened hypertrophic zone (HZ) in the growth plate, simulating the previous reported SEMD pathology in vivo. Instead of the classical modulation mechanism towards SOX9, our further mechanism study found that DDRGK1 stabilizes the stress sensor endoplasmic reticulum-to-nucleus signaling 1 (IRE1α) to maintain endoplasmic reticulum (ER) homoeostasis. The loss of DDRGK1 decreased the UFMylation and subsequently led to increased ubiquitylation-mediated IRE1α degradation, causing ER dysfunction and activating the PERK/CHOP/Caspase3 apoptosis pathway. Further DDRGK1 K268R-mutant mice revealed the importance of K268 UFMylation site in IRE1α degradation and subsequent ER dysfunction. In conclusion, DDRGK1 stabilizes IRE1α to ameliorate ER stress and following apoptosis in chondrocytes, which finally promote the normal chondrogenesis.

A novel radiographic analysis system for subaxial cervical spine pedicle screw placement.

BACKGROUND: Precise pedicle screw placement of the subaxial cervical spine is difficult. Not every hospital is equipped with a guidance system that can provide effective help. Computed tomography (CT) scanning is almost a routine preoperative examination for cervical spine surgery in all hospitals. Appropriate measurement and analysis of the CT images could assist optimal cervical pedicle screw placement. The purpose of this study is to propose a new and universal method using computed tomography (CT) morphological parameters analysis to assist optimal cervical pedicle screw placement from C3 to C7. METHODS: A localization system with six parameters was designed based on preoperative CT reconstruction to guide subaxial cervical spine pedicle screw placement. The six parameters were distance from the starting point to the midline [D1], distance from the starting point to the lower edge of the inferior articular process [D2], transverse section angle [TSA], sagittal section angle [SSA], pedicle width [PW], and pedicle height [PH]. The six parameters were analyzed in 53 participants. RESULTS: Combining D1 and D2 could localize the entrance of the pedicle screw, and we concluded that D1 and TSA and D2 and SSA could be a new standard for determination of the transverse and sagittal orientation of the pedicle screw. The six parameters were closely related to the patient's gender, height, and weight. PH and PW were linearly correlated and could guide selection of the appropriate pedicle screw. SSA was an independent parameter of the relevant vertebral body, and changes in SSA had nothing to do with the curvature or posture of the cervical spine. CONCLUSIONS: Understanding and applying the six-parameter localization system are essential for achieving accurate and optimal pedicle screw placement in subaxial cervical spine, regardless of cervical sagittal alignment.

Verapamil attenuates intervertebral disc degeneration by suppressing ROS overproduction and pyroptosis via targeting the Nrf2/TXNIP/NLRP3 axis in four-week puncture-induced rat models both in vivo and in vitro.

Low back pain is usually caused by intervertebral disc degeneration (IVDD), during which the involvement of oxidation system imbalance and inflammasome activation cannot be neglected. In this study, we aimed to validate the expression level of TXNIP in IVDD and investigate the function and potential mechanism of action of verapamil. TXNIP is upregulated in the degenerate nucleus pulposus in both humans and rats, as well as in tert-butyl hydroperoxide (TBHP)-stimulated nucleus pulposus cells. Administration of verapamil, a classic clinical drug, mitigated the TBHP-induced overproduction of reactive oxygen species and activation of the NLRP3 inflammasome, thus protecting cells from pyroptosis, apoptosis, and extracellular matrix degradation. The Nrf2/TXNIP/NLRP3 axis plays a major role in verapamail-mediated protection. In vivo, a puncture-induced IVDD rat model was constructed, and we found that verapamil delayed the development of IVDD at both the imaging and histological levels. In summary, our results indicate the potential therapeutic effects and mechanisms of action of verapamil in the treatment of IVDD.

DDRGK1 Enhances Osteosarcoma Chemoresistance via Inhibiting KEAP1-Mediated NRF2 Ubiquitination.

Chemoresistance is the main obstacle in osteosarcoma (OS) treatment; however, the underlying mechanism remains unclear. In this study, it is discovered that DDRGK domain-containing protein 1 (DDRGK1) plays a fundamental role in chemoresistance induced in OS. Bioinformatic and tissue analyses indicate that higher expression of DDRGK1 correlates with advanced tumor stage and poor clinical prognosis of OS. Quantitative proteomic analyses suggest that DDRGK1 plays a critical role in mitochondrial oxidative phosphorylation. DDRGK1 knockout trigger the accumulation of reactive oxygen species (ROS) and attenuate the stability of nuclear factor erythroid-2-related factor 2 (NRF2), a major antioxidant response element. Furthermore, DDRGK1 inhibits ubiquitin-proteasome-mediated degradation of NRF2 via competitive binding to the Kelch-like ECH-associated protein 1 (KEAP1) protein, which recruits NRF2 to CULLIN(CUL3). DDRGK1 knockout attenuates NRF2 stability, contributing to ROS accumulation, which promotes apoptosis and enhanced chemosensitivity to doxorubicin (DOX) and etoposide in cancer cells. Indeed, DDRGK1 knockout significantly enhances osteosarcoma chemosensitivity to DOX in vivo. The combination of DDRGK1 knockdown and DOX treatment provides a promising new avenue for the effective treatment of OS.

Secreted phosphoprotein 24 kD (Spp24) inhibits the growth of human osteosarcoma through the BMP-2/Smad signaling pathway.

Autocrine stimulation of tumor cells is an important mechanism for the growth of skeletal tumors. In tumors that are sensitive, growth factor inhibitors can dramatically reduce tumor growth. In this study, our aim was to investigate the effects of Secreted phosphoprotein 24 kD (Spp24) on the growth of osteosarcoma (OS) cells in the presence and absence of exogenous BMP-2 both in vitro and in vivo. Our study demonstrated that Spp24 inhibited proliferation and promoted apoptosis of OS cells as confirmed by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay and immunohistochemical staining. We found that BMP-2 increased the mobility and invasiveness of tumor cells in vitro whereas Spp24 inhibited both of these processes alone and in the presence of exogenous BMP-2. Phosphorylation of Smad1/5/8 and Smad8 gene expression was enhanced by treatment with BMP-2 but inhibited by treatment with Spp24. Subcutaneous and intratibial tumor models in nude mice demonstrated that BMP-2 promoted OS growth in vivo, while Spp24 significantly inhibited tumor growth. We conclude that the BMP-2/Smad signaling pathway is involved in the pathogenesis of OS growth and that Spp24 inhibits the growth of human OS induced by BMP-2 both in vitro and in vivo. Interruption of Smad signaling and increased apoptosis appear to be the primary mechanisms involved. These results confirm the potential of Spp24 as a therapeutic agent for the treatment of OS and other skeletal tumors.

Polydopamine Nanoparticles Targeting Ferroptosis Mitigate Intervertebral Disc Degeneration Via Reactive Oxygen Species Depletion, Iron Ions Chelation, and GPX4 Ubiquitination Suppression.

Intervertebral disc degeneration (IVDD)-induced lower back pain (LBP) is a common problem worldwide. The underlying mechanism is partially accredited to ferroptosis, based on sequencing analyses of IVDD patients from the gene expression omnibus (GEO) databases. In this study, it is shown that polydopamine nanoparticles (PDA NPs) inhibit oxidative stress-induced ferroptosis in nucleus pulposus (NP) cells in vitro. PDA NPs scavenge reactive oxygen species (ROS), chelate Fe2+ to mitigate iron overload, and regulate the expression of iron storage proteins such as ferritin heavy chain (FHC), ferritin, and transferrin receptor (TFR). More importantly, PDA NPs co-localize with glutathione peroxidase 4 (GPX4) around the mitochondria and suppress ubiquitin-mediated degradation, which in turn exerts a protective function via the transformation and clearance of phospholipid hydroperoxides. PDA NPs further down-regulate malondialdehyde (MDA) and lipid peroxide (LPO) production; thus, antagonizing ferroptosis in NP cells. Moreover, PDA NPs effectively rescue puncture-induced degeneration in vivo by targeting ferroptosis and inhibiting GPX4 ubiquitination, resulting in the upregulation of antioxidant pathways. The findings offer a new tool to explore the underlying mechanisms and a novel treatment strategy for IVDD-induced LBP.

Sal003 alleviated intervertebral disc degeneration by inhibiting apoptosis and extracellular matrix degradation through suppressing endoplasmic reticulum stress pathway in rats.

Apoptosis and extracellular matrix degradation of the nucleus pulposus are the main initiators of intervertebral disc degeneration (IVDD) and can be explained by endoplasmic reticulum (ER) stress. Thus, pharmacological therapy aimed at suppressing this pathway may be a promising approach for the management of intervertebral disc degeneration. In this study, we aimed to explore the protective effects of Sal003 against intervertebral disc degeneration and its underlying mechanisms. Thapsigargin (Tg)-stimulated rat nucleus pulposus cells and a needle puncture-induced intervertebral disc degeneration rat model were used to explore the protective effects of Sal003. Our results showed that Sal003 inhibited apoptosis and extracellular matrix degradation by suppressing the endoplasmic reticulum stress pathway. The therapeutic effects of Sal003 were also observed in the intervertebral disc degeneration rat model, as evidenced by improved degeneration along with decreased apoptosis and extracellular matrix degradation in intervertebral discs. Our results demonstrated Sal003 as a potential treatment for intervertebral disc degeneration.

Engeletin Alleviates the Inflammation and Apoptosis in Intervertebral Disc Degeneration via Inhibiting the NF-κB and MAPK Pathways.

Purpose: Low back pain (LBP) induced by intervertebral disc degeneration (IDD) brings progressively painful status and impairs the normal daily living. Engeletin is a plant-derived medicine with anti-inflammation and antioxidant functions. Therefore, we aim to confirm its protective effects against the intervertebral disc degeneration in vivo and in vitro. Methods: The cytotoxicity of engeletin was validated by CCK-8 tests. Using the TNF-α to simulate the inflammation status in vitro, the expression of inflammatory mediators and MMP families were determined by qPCR, Western blotting and confocal microscopy. Cell apoptosis was analyzed by flow cytometry and TUNEL assay. The expression of apoptosis-related proteins was tested by Western blotting. The activation of NF-κB and MAPK pathways was evaluated by Western blotting and confocal microscopy. In vivo, percutaneous needle puncture was used to establish the IDD model in rat, and engeletin was administrated via intradiscal injection. The therapeutic effects of engeletin were detected through imaging and histology analysis. Results: Cell viability tests demonstrated there was little cytotoxicity of engeletin toward NP cells. Pretreatment with engeletin effectively ameliorate the TNF-α-induced up-regulation of inflammatory mediators and MMP families, promoting the anabolism of ECM meanwhile. Cell apoptosis was also attenuated with the addition of engeletin. We found that the activation of MAPK and NF-κB signaling pathways and the nuclear translocation of phosphorylated p65 and p38 were inhibited prominently with the treatment of engeletin which may be the potential molecular mechanism for its anti-inflammation effects. Finally, the IDD induced by percutaneous needle puncture was partially alleviated with the injection of engeletin in vivo. Conclusion: As a natural compound with little cytotoxicity, engeletin possesses the outstanding anti-inflammation and anti-apoptosis effects in the process of IDD in vitro and in vivo, which may be a promising medicine for the prevention and treatment of IDD-related low back pain.

Specific PFKFB3 Inhibitor Memorably Ameliorates Intervertebral Disc Degeneration via Inhibiting NF-κB and MAPK Signaling Pathway and Reprogramming of Energy Metabolism of Nucleus Pulposus Cells.

Intervertebral disc (IVD) degeneration (IVDD) is a characteristic of the dominating pathological processes of nucleus pulposus (NP) cell senescence, abnormal synthesis and irregular distribution of extracellular matrix (ECM), and tumor necrosis factor-α (TNF-α) induced inflammation. Nowadays, IVD acid environment variation which accelerates the pathological processes mentioned above arouses researchers' attention. KAN0438757 (KAN) is an effective inhibitor of selective metabolic kinase phosphofructokinase-2/fructose-2,6-bisphosphatase 3 (PFKFB3) that has both energy metabolism reprogramming and anti-inflammatory effects. Therefore, a potential therapeutic benefit of KAN lies in its ability to inhibit the development of IVDD. This study examined in vitro KAN toxicity in NP primary cells (NPPs). Moreover, KAN influenced tumor necrosis factor-α (TNF-α) induced ECM anabolism and catabolism; the inflammatory signaling pathway activation and the energy metabolism phenotype were also examined in NPPs. Furthermore, KAN's therapeutic effect was investigated in vivo using the rat tail disc puncture model. Phenotypically speaking, the KAN treatment partially rescued the ECM degradation and glycolysis energy metabolism phenotypes of NPPs induced by TNF-α. In terms of mechanism, KAN inhibited the activation of MAPK and NF-κB inflammatory signaling pathways induced by TNF-α and reprogramed the energy metabolism. For the therapeutic aspect, the rat tail disc puncture model demonstrated that KAN has a significant ameliorated effect on the progression of IVDD. To sum up, our research successfully authenticated the potential therapeutic effect of KAN on IVDD and declaimed its mechanisms of both novel energy metabolism reprogramming and conventional anti-inflammation effect.

Curcumenol Mitigates the Inflammation and Ameliorates the Catabolism Status of the Intervertebral Discs In Vivo and In Vitro via Inhibiting the TNFα/NFκB Pathway.

Low back pain (LBP) caused by intervertebral disc degeneration (IVDD) is accredited to the release of inflammatory cytokines followed by biomechanical and structural deterioration. In our study, we used a plant-derived medicine, curcumenol, to treat IVDD. A cell viability test was carried out to evaluate the possibility of using curcumenol. RNA-seq was used to determine relative pathways involved with curcumenol addition. Using TNFα as a trigger of inflammation, the activation of the NF-κB signaling pathway and expression of the MMP family were determined by qPCR and western blotting. Nucleus pulposus (NP) cells and the rats' primary NP cells were cultured. The catabolism status was evaluated by an ex vivo model. A lumbar instability mouse model was carried out to show the effects of curcumenol in vivo. In general, RNA-seq revealed that multiple signaling pathways changed with curcumenol addition, especially the TNFα/NF-κB pathway. So, the NP cells and primary NP cells were induced to suffer inflammation with the activated TNFα/NF-κB signaling pathway and increased expression of the MMP family, such as MMP3, MMP9, and MMP13, which would be mitigated by curcumenol. Owing to the protective effects of curcumenol, the height loss and osteophyte formation of the disc could be prevented in the lumbar instability mouse model in vivo.

Prussian Blue Nanoparticles Stabilize SOD1 from Ubiquitination-Proteasome Degradation to Rescue Intervertebral Disc Degeneration.

Discography often destroys the hypoxic environment in the intervertebral disc and accelerates intervertebral disc degeneration (IVDD). Therefore, it often fails to meet the requirements for application in clinical practice. This technology mainly increases the reactive oxygen species (ROS) in the IVD. As so, it is particularly critical to develop strategies to avoid this degeneration mechanism. Prussian blue nanoparticles (PBNPs) are found to enhance development under magnetic resonance T1 and have antioxidant enzyme activity. The key results of the present study confirm that PBNPs alleviate intracellular oxidative stress and increase the intracellular activities of antioxidant enzymes, such as superoxide dismutase 1 (SOD1). PBNPs can rescue nucleus pulposus cell degeneration by increasing oxidoreductase system-related mRNA and proteins, especially by stabilizing SOD1 from ubiquitination-proteasome degradation, thus improving the mitochondrial structure to increase antioxidation ability, and finally rescuing ROS-induced IVDD in a rat model. Therefore, it is considered that PBNPs can be a potential antioxidation-protective discography contrast agent.

Curcumenol mitigates chondrocyte inflammation by inhibiting the NF­κB and MAPK pathways, and ameliorates DMM­induced OA in mice.

At present, an increasing number of individuals are affected by osteoarthritis (OA), resulting in a heavy socioeconomic burden. OA in knee joints is caused by the release of inflammatory cytokines and subsequent biomechanical and structural deterioration. To determine its anti­inflammatory function, the current study investigated the use of the plant­derived medicine, curcumenol, in OA treatment. Curcumenol was not cytotoxic to ATDC5 chondrocytes and primary chondrocytes, as determined using a cell viability test. When these cells were treated with TNF­α and IL­1ß to induce inflammation, curcumenol treatment inhibited the progression of inflammation by inactivating the NF­κB and MAPK signaling pathways, as well as decreasing the expression levels of MMP3 (as indicated by reverse transcription­quantitative PCR and western blotting). Moreover, to analyze metabolic and catabolic status in high­density and pellet culture, catalytic changes and the degradation of the extracellular matrix induced by TNF­α and IL­1ß, were evaluated by alcian blue staining. These catalytic deteriorations were ameliorated by curcumenol. Using curcumenol in disease management, the mechanical and metabolic disruption of cartilage caused in the destabilization of medial meniscus (DMM) model was prevented in vivo. Thus, curcumenol mitigated inflammation in ATDC5 chondrocytes and primary mice chondrocytes, and also ameliorated OA in a DMM­induced mouse model.

Dehydrocostus Lactone Attenuates the Senescence of Nucleus Pulposus Cells and Ameliorates Intervertebral Disc Degeneration via Inhibition of STING-TBK1/NF-κB and MAPK Signaling.

The progression of intervertebral disc degeneration (IDD) is multifactorial with the senescence of nucleus pulposus (NP) cells and closely related to inflammation in NP cells. Dehydrocostus lactone (DHE) is a natural sesquiterpene lactone isolated from medicinal plants that has anti-inflammatory properties. Thus, DHE may have a therapeutic effect on the progression of IDD. In this study, NP cells were used to determine the appropriate concentration of DHE in vitro. The role of DHE in tumor necrosis factor-α (TNF-α)-induced activation of inflammatory signaling pathways and cellular senescence, together with anabolism and catabolism of extracellular matrix (ECM) in NP cells, was examined in vitro. The therapeutic effect of DHE in vivo was determined using a spinal instability model of IDD in mice. The TNF-α-induced ECM degradation and the senescence of NP cells were partially attenuated by DHE. Mechanistically, DHE inhibited the activation of NF-κB and MAPK inflammatory signaling pathways and ameliorated the senescence of NP cells caused by the activation of STING-TBK1/NF-κB signaling induced by TNF-α. Furthermore, a spinal instability model in mice demonstrated that DHE treatment could ameliorate progression of IDD. Together, our findings indicate that DHE can alleviate IDD changes and has a potential therapeutic function for the treatment of IDD.

Laminoplasty with selective fusion at unstable segment versus laminectomy with fusion for multilevel cervical myelopathy: a case-control study.

BACKGROUND: Segmental cervical instability is a risk factor for the progression of osteophytic bone spurs and development of myelopathy, and is treated as a relative contraindication of cervical laminoplasty. The aim of this study was to compare laminoplasty with selective fixation (LPSF) versus laminectomy with fusion (LCF) in patients with multilevel cervical myelopathy accompanied by segmental instability. METHODS: A case-control study was conducted by reviewing data from 63 patients who underwent LPSF (n = 30) or LCF (n = 33). Cervical alignment, range of motion (ROM), neurologic status and axial symptom severity pre-operation, 3-days after operation, and at the final follow-up (minimum 24 months) were measured and compared between groups. RESULTS: Postoperation, patients in the LPSF group lost 31.1 ± 17.3 % of cervical lordosis and 43.2 ± 10.9 % cervical ROM while patients in the LCF group lost 5.7 ± 8.2 % and 67.9 ± 15.5 %, respectively. Both LPSF and LCF groups significantly improved neurologic status and axial symptom severity at the final follow-up with similar between-group results(P > 0.05). Blood loss, operation time, hospital stay, and medical cost in the LPSF group were significantly less than in the LCF group(P < 0.05). CONCLUSIONS: In 2 years of clinical observation, LPSF was effective in maintaining the stability of the cervical spine with less sacrifice of mobility and surgical trauma for multilevel myelopathy with segmental instability compared to LCF.

Antibacterial efficacy of quaternized chitosan coating on 3D printed titanium cage in rat intervertebral disc space.

BACKGROUND CONTEXT: Infection around intervertebral fusion cages can be intractable because of the avascular nature of the intervertebral disc space. Intervertebral cages with antibacterial effects may be a method by which this complication can be prevented. PURPOSE: To investigate the bacterial load on the antibacterial coating cages for spinal interbody fusion STUDY DESIGN: An experimental in vitro and in vivo study. METHODS: Based on the micro-computed tomography (CT) data of rat caudal discs, mesh-like titanium (Ti) cages that anatomically fit into the discs were fabricated by three-dimensional (3D) printing. Additionally, an antibacterial coating was applied with quaternized chitosan (hydroxypropyltrimethyl ammonium chloride chitosan, HACC). In vitro release kinetics of the HACC was performed, and the antibacterial performance of the HACC-coated (Ti-HACC) cages (via inhibition zone assay, bacterial adhesion assay, and biofilm formation assay) was evaluated. Then, Ti-HACC- or noncoated (Ti) cages were implanted in the caudal discs of rats with bioluminescent Staphylococcus aureus. Bacterial survival was investigated using an in vivo imaging system (IVIS) on postoperative days 1, 3, and 5. On day 5, the infection-related changes (bone destruction and migration of cages) were assessed using micro-CT, and the healing status of the surgical wounds was also assessed. After the removal of the cages, the quantification of bacteria attached to the cages was obtained by IVIS. Histological evaluation was performed by hematoxylin and eosin staining and TRAP (tartrate-resistant acid phosphatase) staining. RESULTS: Release kinetic analysis showed the sustained release of HACC over 3 days from Ti-HACC cages. Antibacterial effects of Ti-HACC cages were demonstrated in all in vitro assays. IVIS evaluation indicated that the in vivo implantation of Ti-HACC cages with S. aureus exhibited better wound healing, less infection-related changes on micro-CT, and reduced bacterial quantity in the extracted cages compared to Ti cages. Histological evaluation demonstrated an increased number of TRAP-positive osteoclasts and severe bone destruction in the rats treated with Ti cages. CONCLUSIONS: We developed a novel antibacterial HACC-coated intervertebral cage that exhibited prominent antibacterial efficacy and prevented the structural damage caused by the infection in rat caudal discs. CLINICAL SIGNIFICANCE: HACC-coated titanium intervertebral cages may be a promising option for preventing intractable postoperative infection in spinal interbody fusion surgery.

A novel COL2A1 mutation causing spondyloepiphyseal dysplasia congenita in a Chinese family.

BACKGROUND: Spondyloepiphyseal dysplasia congenita is an autosomal dominant cartilaginous dysplasia characterized by short trunk, abnormal epiphysis, and flattened vertebral body. Skeletal features of SEDC are present at birth and evolve over time. Other features of SEDC include myopia and/or retinal degeneration with retinal detachment and cleft palate. A mutation in the COL2A1 gene located in 12q13.11 is considered as one of the important causes of SEDC. In 2016, Barat-Houari et al. reported a large number of COL2A1 mutations. Among them, a non-synonymous mutation in COL2A1 exon 37, c.2437G>A (p. Gly813Arg), has been reported to cause SEDC in only one patient from France so far. METHODS: We followed up a patient with SEDC phenotype and his family members. The clinical manifestations, physical examination and imaging examination, including X-ray, CT and MRI, were recorded. The whole-exome sequencing was used to detect the patients' genes, and the pathogenic genes were screened out by comparing with many databases. RESULTS: We report a Chinese patient with SEDC phenotype characterized by short trunk, abnormal epiphysis, flattened vertebral body, narrow intervertebral space, dysplasia of the odontoid process, chicken chest, scoliosis, hip and knee dysplasia, and joint hypertrophy. Gene sequencing analysis showed that the patient had a heterozygous mutation (c.2437G>A; p. Gly813Arg) in the COL2A1 gene. No COL2A1 mutation or SEDC phenotype was observed in his family members. This is the first report of SEDC caused by this mutation in an East Asian family. CONCLUSION: This report provides typical clinical, imaging, and genetic evidence for SEDC, confirming that a de novo mutation in the COL2A1 gene, c.2437G>A (p. Gly813Arg), causes SEDC in Chinese population.

Bleomycin induces fibrotic transformation of bone marrow stromal cells to treat height loss of intervertebral disc through the TGFßR1/Smad2/3 pathway.

BACKGROUND: Lower back pain is often accredited to loss of intervertebral disc (IVD) height and compromised spine stability as a result of intervertebral disc degeneration (IVDD). We aim to locally use bleomycin to induce the fibrotic transformation of bone marrow stromal cells (BMSCs) as a means to induce reparative fibrosis to slow down the height loss. METHODS: IVDs from patients were gathered for histological examination. The expression of the transforming growth factor beta 1 (TGF-ß) signaling pathway was determined by qPCR and western blotting. Nucleus pulposus (NP) cells, annulus fibrosus (AF) cells, and the rats' bone marrow stromal cells (BMSC) were cultured and their responsiveness to bleomycin was evaluated by Cell Counting Kit-8, comet assay, transwell migration, and wound healing assays. Rat IVDD models were created by puncture and rescued by bleomycin injection, and the effectiveness was evaluated by images (X-ray and MRI) and atomic force microscope. RESULTS: Histological examination showed increased levels of pro-fibrotic markers in IVDD tissues from patients. AF cells and BMSC cells were induced to adopt a pro-fibrotic phenotype with increased expression fibrotic markers Col1a1, Col3a1, and FSP1. The pro-fibrotic effect of bleomycin on AF cells and BMSCs was in part due to the activation of the TGFß-TGFßR1-SMAD2/3 signaling pathway. Pharmacological inhibition or gene knock-down of TGFßR1 could mitigate the pro-fibrotic effects. CONCLUSION: Locally, injection of bleomycin in rats' IVD induced rapid fibrosis and maintained its height through the TGFß-TGFßR1-SMAD2/3 signaling pathway.

A novel system for accurate lumbar spine pedicle screw placement based on three-dimensional computed tomography reconstruction.

OBJECTIVES: The accuracy of pedicle screw placement strongly affects the outcome of spinal surgery and has mainly relied on the surgeons' experience. There is no simple, low-cost, and effective pedicle screw placement system to assist new spinal surgeons with less experience. METHODS: We designed a localization system with six parameters (starting point height [SP-H], starting point length [SP-L], transverse section angle, sagittal section angle [SSA], pedicle width [W] and height [H]) based on preoperative computed tomography reconstruction and combined it with the Roussouly classification to guide lumbar spine pedicle screw placement and analysed the change patterns of the six parameters in 50 participants. RESULTS: Based on the system, we confirmed that combining SP-H and SP-L can localize the entrance of the pedicle screw. Furthermore, we considered that SP-L and transverse section angle would be a new standard for determination of the transverse orientation of the pedicle screw. More importantly, the linear regression equations between H and W and SP-H and H were concealed. In addition, H and W can guide the appropriate selection of pedicle screw. Moreover, change patterns of SSA combined with the Roussouly classification indicate that SSA of L3 can be used as a benchmark to guide the establishment of sagittal alignment of the lumbar spine. CONCLUSIONS: Understanding and applying the six-parameter localization system are essential for achieving accuracy in lumbar spine pedicle screw placement, and the system is a useful guide in the establishment of sagittal alignment. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: This study provides a new pedicle-screw placement system for accurate lumbar spine pedicle screw placement based on three-dimensional CT reconstruction, requiring six parameters to guide the system.

Autologous fibroblasts induce fibrosis of the nucleus pulposus to maintain the stability of degenerative intervertebral discs.

Lumbar degenerative disc diseases cause low back pain (LBP). The maintenance of the height and stability of the intervertebral disc (IVD) space is an effective treatment for LBP. The following study evaluated the effects of fibroblast injection on intervertebral disc degeneration (IDD) in a preclinical setting. Compared with the IDD group, the fibroblast treatment group demonstrated effective maintenance of IVD height, reduced endplate degeneration, and improved nuclear magnetic resonance signals and overall histological structure. In doing so, fibrotic IVDs maintained the stability and biomechanics of the vertebra. This finding is in agreement with clinical findings that human nucleus pulposus (NP) fibrosis is essential for the maintenance of IVD height and mechanical properties in patients following percutaneous endoscopic lumbar discectomy (PELD). Mechanistically, we demonstrated that injected fibroblasts not only proliferated but also induced NP cells to adopt a fibrotic phenotype via the secretion of TGF-ß. Finally, to better mimic human conditions, the efficacy of autologous fibroblast injection in the treatment of IDD was further examined in a nonhuman primate cynomolgus monkey model due to their capacity for upright posture. We showed that the injection of fibroblasts could maintain the IVD height and rescue IVD signals in cynomolgus monkeys. Taken together, the results of our study reveal that autologous fibroblast injection can enhance the natural process of fibrosis during acute and subacute stages of stress-induced IDD. Fibrotic IVDs can maintain the stability, biological activity, and mechanical properties of the intervertebral space, thus providing a new direction for the treatment of intervertebral space-derived lumbar degenerative diseases.