Dedifferentiation-like reprogramming of degenerative nucleus pulposus cells into notochordal-like cells by defined factors.

The extensive degeneration of functional somatic cells and the depletion of endogenous stem/progenitor populations present significant challenges to tissue regeneration in degenerative diseases. Currently, a cellular reprogramming approach enabling directly generating corresponding progenitor populations from degenerative somatic cells remains elusive. The present study focused on intervertebral disc degeneration (IVDD) and identified a three-factor combination (OCT4, FOXA2, TBXT [OFT]) that could induce the dedifferentiation-like reprogramming of degenerative nucleus pulposus cells (dNPCs) toward induced notochordal-like cells (iNCs). Single-cell transcriptomics dissected the transitions of cell identity during reprogramming. Further, OCT4 was found to directly interact with bromodomain PHD-finger transcription factor to remodel the chromatin during the early phases, which was crucial for initiating this dedifferentiation-like reprogramming. In rat models, intradiscal injection of adeno-associated virus carrying OFT generated iNCs from in situ dNPCs and reversed IVDD. These results collectively present a proof-of-concept for dedifferentiation-like reprogramming of degenerated somatic cells into corresponding progenitors through the development of a factor-based strategy, providing a promising approach for regeneration in degenerative disc diseases.

A novel rat model of annulus fibrosus injury for intervertebral disc degeneration.

BACKGROUND CONTEXT: In clinical practice, acute trauma and chronic degeneration of the annulus fibrosus (AF) can promote further degeneration of the intervertebral disc (IVD). Therefore, it is critical to understand the AF repair process and its consequences on IVD. However, the lack of cost-effective and reproducible in vivo animal models of AF injury has limited research development in this field. PURPOSES: The purpose of this study was to establish and evaluate the utility of a novel animal model for full-thickness AF injury. Three foci were proposed: (1) whether this new modeling method can cause full-layer AF damage; (2) the repair processes and pathological changes in the damaged area after AF injury, and (3) the morphological and histological changes in the IVD are after AF injury. STUDY DESIGN/SETTING: In vivo rat AF injury model with characterization of AF damage repair, IVD degeneration. METHODS: A total of 72,300 g male rats were randomly assigned to one of the two groups: experimental or sham. Annulus fibrosus was separated layer by layer under the microscope with a #11 blade up to the AF- nucleus pulpous (NP) junction. The repair process of the horizontal AF and morphological changes in the sagittal IVD were evaluated with HE staining. Sirius red staining under polarized light. Immunofluorescence was conducted to analyze changes in the expression of COL1 and COL3 in the AF injury area and 8-OHdg, IL-6, MMP13, FSP1, and ACAN in the IVD. The disc height and structural changes after AF injury were measured using X-ray and contrast-enhanced micro-CT. Additionally, the resistance of the AF to stretching was analyzed using three-point bending. RESULTS: Annulus fibrosus-nucleus pulpous border was identified to stably induce the full-thickness AF injury without causing immediate NP injury. The AF repair process after injury was slow and expressed inflammation factors continuously, with abundant amounts of type III collagen appearing in the inner part of the AF. The scar at the AF lesion had decreased resistance to small molecule penetration and weakened tensile strength. Full-thickness AF injury induced disc degeneration with loss of disc height, progressive unilateral vertebral collapse, and ossification of the subchondral bone. Inflammatory-induced degeneration and extracellular matrix catabolism gradually appeared in the NP and cartilage endplate (CEP). CONCLUSIONS: We established a low-cost and reproducible small animal model of AF injury which accurately replicated the pathological state of the limited AF self-repair ability and demonstrated that injury to the AF alone could cause further degeneration of the IVD. CLINICAL RELEVANCE: This in vivo rat model can be used to study the repair process of the AF defect and pathological changes in the gradual degeneration of IVD after AF damage. In addition, the model provides an experimental platform for in vivo experimental research of potential clinical therapeutics.

Case Report: Metagenomic Next-Generation Sequencing Confirmed a Case of Spine Infection with Brucella melitensis in Non-Endemic Area.

Brucellosis is a zoonotic disease caused by Brucella spp., with the highest prevalence found in the northern cities of China. In this case report, we present an occurrence of spinal infection caused by B. melitensis in a 67-year-old man residing in a non-endemic area of southern China. The patient initially presented with chest and back pain, which was not accurately diagnosed and treated at a local hospital. Subsequently, due to worsening pain, he was admitted to our hospital. To determine the cause of the infection, we performed CT-guided aspiration biopsy and collected biopsy tissue for metagenomic next-generation sequencing (mNGS) on the second day of hospitalization. Imaging investigations revealed involvement of the thoracic vertebrae, specifically thoracic 4-7 with the main focus on 5-6, accompanied by stenosis of the intervertebral space. The mNGS results indicated that the spine infection was caused by B. melitensis. The patient's history as a shepherd and a positive Rose Bengal plate test (RBPT) further supported the diagnosis of brucella spondylitis. In order to alleviate pain and restore spinal function, the patient underwent posterior internal fixation of the thoracic spine. Treatment was initiated with cefoperazone/sulbactam, followed by doxycycline. Subsequently, the patient was switched to a combination therapy of rifampicin and doxycycline for a duration of six weeks. The patient responded well to treatment, and his condition remained stable. In conclusion, brucellosis is a common disease that can be easily misdiagnosed. This case report highlights the potential value of mNGS in early and rapid diagnosis. We believe that mNGS can serve as an effective tool to improve the diagnosis of spine infections caused by this pathogen.

Adiponectin inhibits GnRH secretion via activating AMPK and PI3K signaling pathways in chicken hypothalamic neuron cells.

It has been reported that adiponectin (AdipoQ), an adipokine secreted by white adipose tissue, plays an important role in the control of animal reproduction in addition to its function in energy homeostasis by binding to its receptors AdipoR1/2. However, the molecular mechanisms of AdipoQ in the regulation of animal reproduction remain elusive. In this study, we investigated the effects of AdipoQ on hypothalamic reproductive hormone (GnRH) secretion and reproduction-related receptor gene (estrogen receptor [ER] and progesterone receptor [PR]) expression in hypothalamic neuronal cells (HNCs) of chickens by using real-time fluorescent quantitative PCR (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), Western blot (WB) and cell counting kit-8 (CCK-8) assays and found that overexpression of AdipoQ could increase the expression levels of AdipoR1/2 and reproduction-related receptor genes (P < 0.05) while decreasing the expression level of GnRH. In contrast, interference with AdipoQ mRNA showed the opposite results in HNCs. Furthermore, we demonstrated that AdipoQ exerts its functions through the AMPK and PI3K signaling pathways. Finally, our in vitro experiments found that AdipoRon (a synthetic substitute for AdipoQ) treatment and AdipoR1/2 RNAi interference co-treatment resulted in no effect on GnRH secretion, suggesting that the inhibition of GnRH secretion by AdipoQ is mediated by the AdipoR1/2 signaling axis. In summary, we uncovered, for the first time, the molecular mechanism of AdipoQ in the regulation of reproductive hormone secretion in hypothalamic neurons in chickens.

Thermosensitive hydrogel-based GPR124 delivery strategy for rebuilding blood-spinal cord barrier.

Spinal cord injury (SCI) causes blood-spinal cord barrier (BSCB) disruption, leading to secondary damage, such as hemorrhagic infiltration, inflammatory response, and neuronal cell death. It is of great significance to rebuild the BSCB at the early stage of SCI to alleviate the secondary injury for better prognosis. Yet, current research involved in the reconstruction of BSCB is insufficient. Accordingly, we provide a thermosensitive hydrogel-based G protein-coupled receptor 124 (GPR124) delivery strategy for rebuilding BSCB. Herein, we firstly found that the expression of GPR124 decreased post-SCI and demonstrated that treatment with recombinant GPR124 could partially alleviate the disruption of BSCB post-SCI by restoring tight junctions (TJs) and promoting migration and tube formation of endothelial cells. Interestingly, GPR124 could also boost the energy metabolism of endothelial cells. However, the absence of physicochemical stability restricted the wide usage of GPR124. Hence, we fabricated a thermosensitive heparin-poloxamer (HP) hydrogel that demonstrated sustained GPR124 production and maintained the bioactivity of GPR124 (HP@124) for rebuilding the BSCB and eventually enhancing functional motor recovery post-SCI. HP@124 hydrogel can encapsulate GPR124 at the lesion site by injection, providing prolonged release, preserving wounded tissues, and filling injured tissue cavities. Consequently, it induces synergistically efficient integrated regulation by blocking BSCB rupture, decreasing fibrotic scar formation, minimizing inflammatory response, boosting remyelination, and regenerating axons. Mechanistically, giving GPR124 activates energy metabolism via elevating the expression of phosphoenolpyruvate carboxykinase 2 (PCK2), and eventually restores the poor state of endothelial cells. This research demonstrated that early intervention by combining GPR124 with bioactive multifunctional hydrogel may have tremendous promise for restoring locomotor recovery in patients with central nervous system disorders, in addition to a translational approach for the medical therapy of SCI.

Controlled extracellular vesicles release from aminoguanidine nanoparticle-loaded polylysine hydrogel for synergistic treatment of spinal cord injury.

Pharmaceutical treatments are critical for the acute and subacute phases of spinal cord injury (SCI) and significantly impact patients' prognoses. However, there is a lack of a precise, multitemporal, integrated drug delivery system for medications administered in both phases. In this study, we prepare a hybrid polylysine-based hydrogel (PBHEVs@AGN) comprising short-term release of pH-responsive aminoguanidine nanoparticles (AGN) and sustained release of extracellular vesicles (EVs) for synergistic SCI treatment. When AGN is exposed to the acidic environment at the injury site, it quickly diffuses out of the hydrogel and releases the majority of the aminoguanidine within 24 h, reducing oxidative stress in lesion tissues. Enriched EVs are gradually released from the hydrogel and remain in the tissue for weeks, providing a long-term anti-inflammatory effect and further ensuring axonal regeneration. Fast-releasing aminoguanidine can cooperate with slow-release EVs to treat SCI more effectively by reducing the production of proinflammatory cytokines and blocking the TLR4/Myd88/NF-κB inflammatory pathway, creating a sustained anti-inflammatory microenvironment for SCI recovery. Our in vivo experiments demonstrate that PBHEVs@AGN reduces the occurrence of scar tissue, encourages remyelination, and speeds up axonal regeneration. Herein, this multi-drug delivery system, which combines the acute release of aminoguanidine and the sustained release of EVs is highly effective for synergistically managing the challenging pathological processes after SCI.

Nucleus pulposus cell-derived efficient microcarrier for intervertebral disc tissue engineering.

Adipose-derived stem cells (ADSCs) show great potential for the treatment of intervertebral disc (IVD) degeneration. An ideal carrier is necessary to transplant ADSCs into degenerated IVDs without influencing cell function. Nucleus pulposus cells (NPCs) can synthesize and deposit chondroitin sulfate and type II collagen which are NP-specific extracellular matrix (ECM) and can also regulate the NP-specific differentiation of stem cells. Bioscaffolds fabricated based on the ECM synthesis functions of NPCs have possible roles in cell transplantation and differentiation induction, but it has not been studied. In this study, we first aggregated NPCs into pellets, and then, NPC-derived efficient microcarriers (NPCMs) were fabricated by pellet cultivation under specific conditions and optimized decellularization. Thirdly, we evaluated the microstructure, biochemical composition, biostability and cytotoxicity of the NPCMs. Finally, we investigated the NP-specific differentiation of ADSCs induced by the NPCMsin vitroand NP regeneration induced by the ADSC-loaded NPCMs in a rabbit model. The results indicated that the injectable NPCMs retained maximal ECM and minimal cell nucleic acid after optimized decellularization and had good biostability and no cytotoxicity. The NPCMs also promoted the NP-specific differentiation of ADSCsin vitro. In addition, the results of MRI, x-ray, and the structure and ECM content of NP showed that the ADSCs-loaded NPCMs can partly restored the degenerated NPin vivo. Our injectable NPCMs regenerated the degenerated NP and provide a simplified and efficient strategy for treating IVD degeneration.

Direct Reprogramming in Bone and Joint Degenerative Diseases: Applications, Obstacles and Directions.

With a booming aging population worldwide, bone and joint degenerative diseases have gradually become a major public health focus, attracting extensive scientific attention. However, the effective treatments of these degenerative diseases have been confined to traditional medications and surgical interventions, which easily lead to the possibility of drug abuse or loss of physiological function to varying degrees. Recently, given that the development of reprogramming has overcome shackles in the field of degenerative diseases, direct reprogramming would provide a new concept to accelerate progress in the therapy of bone and joint degenerative diseases. The process of direct reprogramming would directly induce ordinary somatic cells to the desired targeted cells without passing through pluripotent cell states. In this review, we summarize some direct reprogramming of cells that has been attempted for the repair of common bone and joint degenerative diseases, such as osteoarthritis, osteoporosis-related fracture and intervertebral disc degeneration. However, it is inevitable that some obstacles, such as accurate transcription factors, an appropriate extracellular microenvironment and efficient delivery carriers in vivo, need to be resolved. In addition, developmental and promising directions associated with direct reprogramming have attracted public attention. Investigation of the regulation of the transient genome, metabolic conversion and cellular skeleton would provide superior potential candidates for the revolution of direct reprogramming. The aim of direct reprogramming is to directly provide target cells for cell therapy and even tissue reconstruction in bone and joint degenerative diseases. Moreover, the development of direct reprogramming have potential to achieve repair and even reconstruct in situ, which would be breakthrough effect for the repair of bone and joint degenerative diseases. The advance of direct reprogramming has opened numerous opportunities for new therapeutic strategies in regenerative medicine.

CircEML1 facilitates the steroid synthesis in follicular granulosa cells of chicken through sponging gga-miR-449a to release IGF2BP3 expression.

Non-coding RNAs (ncRNAs) induced competing endogenous RNAs (ceRNA) play crucial roles in various biological process by regulating target gene expression. However, the studies of ceRNA networks in the regulation of ovarian ovulation processing of chicken remains deficient compared to that in mammals. Our present study revealed that circEML1 was differential expressed in hen's ovarian tissues at different ages (15 W/20 W/30 W/68 W) and identified as a loop structure from EML1 pre-mRNA, which promoted the expressions of CYP19A1/StAR and E2/P4 secretion in follicular granulosa cells (GCs). Furthermore, circEML1 could serve as a sponge of gga-miR-449a and also found that IGF2BP3 was targeted by gga-miR-449a to co-participate in the steroidogenesis, which possibly act the regulatory role via mTOR/p38MAPK pathways. Meanwhile, in the rescue experiment, gga-miR-449a could reverse the promoting role of circEML1 to IGF2BP3 and steroidogenesis. Eventually, this study suggested that circEML1/gga-miR-449a/IGF2BP3 axis exerted an important role in the steroidogenesis in GCs of chicken.

Swelling-Mediated Mechanical Stimulation Regulates Differentiation of Adipose-Derived Mesenchymal Stem Cells for Intervertebral Disc Repair Using Injectable UCST Microgels.

Mechanical stimulation is an effective approach for controlling stem cell differentiation in tissue engineering. However, its realization in in vivo tissue repair remains challenging since this type of stimulation can hardly be applied to injectable seeding systems. Here, it is presented that swelling of injectable microgels can be transformed to in situ mechanical stimulation via stretching the cells adhered on their surface. Poly(acrylamide-co-acrylic acid) microgels with the upper critical solution temperature property are fabricated using inverse emulsion polymerization and further coated with polydopamine to increase cell adhesion. Adipose-derived mesenchymal stem cells (ADSCs) adhered on the microgels can be omnidirectionally stretched along with the responsive swelling of the microgels, which upregulate TRPV4 and Piezo1 channel proteins and enhance nucleus pulposus (NP)-like differentiation of ADSCs. In vivo experiments reveal that the disc height and extracellular matrix content of NP are promoted after the implantation with the microgels. The findings indicate that swelling-induced mechanical stimulation has great potential for regulating stem cell differentiation during intervertebral disc repair.

Collagen Niches Affect Direct Transcriptional Conversion toward Human Nucleus Pulposus Cells via Actomyosin Contractility.

Cellular niches play fundamental roles in regulating cellular behaviors. However, the effect of niches on direct converted cells remains unexplored. In the present study, the specific combination of transcription factors is first identified to directly acquire induced nucleus pulposus-like cells (iNPLCs). Next, tunable physical properties of collagen niches are fabricated based on various crosslinking degrees. Collagen niches significantly affect actomyosin cytoskeleton and then influence the maturation of iNPLCs. Using gain- and loss of function approaches, the appropriate physical states of collagen niches are found to significantly enhance the maturation of iNPLCs through actomyosin contractility. Moreover, in a rat model of degenerative disc diseases, iNPLCs with collagen niches are transplanted into the lesion to achieve significant improvements. As a result, overexpression of transcription factors in human dermal fibroblasts are efficiently converted into iNPLCs and the optimal collagen niches affect cellular cytoskeleton and then facilitate iNPLCs maturation toward human nucleus pulposus cells. These findings encourage more in-depth studies toward the interactions of niches and direct conversion, which would contribute to the development of direct conversion.

FABP4 knockdown suppresses inflammation, apoptosis and extracellular matrix degradation in IL-1ß-induced chondrocytes by activating PPARγ to regulate the NF-κB signaling pathway.

Osteoarthritis (OA) is a common degenerative disease that can lead to severe joint pain and loss of function, seriously threatening the health and normal life of patients. At present, the pathogenesis of OA remains to be clarified. Recent studies have shown that fatty acid­binding protein 4 (FABP4) is increased in the plasma and synovial fluid of patients with OA. However, the effect of FABP4 on OA is unclear. The present study established IL­1ß­induced ATDC5 cells with FABP4 knockdown. Next, cell viability was detected with Cell Counting Kit­8 assay. The content of inflammatory factors, prostaglandin E2 and glycosaminoglycan (GAG) was detected via ELISA. The levels of reactive oxygen species (ROS) and superoxide dismutase (SOD) in cells were detected by using ROS and SOD kits, respectively. TUNEL staining was used to detect the apoptosis level. Western blotting was used to detect the expression levels of proteins. The results revealed that FABP4 was upregulated in IL­1ß­induced ATDC5 cells. Knockdown of FABP4 increased cell viability, reduced inflammatory damage, oxidative stress and apoptosis in IL­1ß­induced ATDC5 cells. Following FABP4 knockdown, the expression of matrix metalloproteinases (MMP3, MMP9 and MMP13) of IL­1ß­induced ATDC5 cells was reduced, and the expression of GAG was promoted. FABP4 knockdown also inhibited the expression of NF­κB p65 and enhanced peroxisome proliferator­activated receptor (PPAR)γ expression. However, the presence of PPARγ inhibitor blocked the aforementioned effects of FABP4 on IL­1ß­induced ATDC5 cells. In conclusion, FABP4 knockdown suppressed the inflammation, oxidative stress, apoptosis and extracellular matrix degradation of IL­1ß­induced chondrocytes by activating PPARγ to inhibit the NF­κB signaling pathway.

Is stand-alone lateral lumbar interbody fusion superior to instrumented lateral lumbar interbody fusion for the treatment of single-level, low-grade, lumbar spondylolisthesis?

BACKGROUND: The aim of this study was to compare surgical trauma and radiographic and clinical outcomes of stand-alone and instrumented lateral lumbar interbody fusion (LLIF) in the treatment of single-level low-grade lumbar spondylolisthesis. METHODS: Ninety-five patients with single-level low-grade lumbar spondylolisthesis, who underwent stand-alone LLIF (stand-alone group, [n = 54]) or LLIF plus percutaneous posterior fixation (instrumented group, [n = 41]) were enrolled in this study. Operative time, intraoperative blood loss, serum C-reactive protein (CRP) and creatine kinase (CK) levels, the length of postoperative bed rest time, and hospital stay were compared between the 2 groups. Disc height, the percent of slip, segment lordosis, lumbar lordosis, the visual analog scale score, the Oswestry Disability Index and complications were also compared. RESULTS: Operative and bed rest time were shorter, intraoperative blood loss was less, and postoperative CRP and CK levels were lower in the stand-alone group. During follow-up, 6 patients in stand-alone group underwent posterior fixation due to cage subsidence. Although satisfactory radiographic results were achieved in both groups, the maintenance of increased disc heights and segment lordosis was inferior in the stand-alone group at the final follow-up. Greater improvement in postoperative VAS scores and ODI were observed in the stand-alone group, although the rates of cage subsidence and revision were higher. CONCLUSION: Stand-alone LLIF was superior to instrumented LLIF in terms of tissue trauma for the treatment of single-level low-grade lumbar spondylolisthesis. However, stand-alone LLIF was inferior in the maintenance of disc height and segment lordosis, and the occurrence of cage subsidence and revision.

Prognosis of prostate cancer and bone metastasis pattern of patients: a SEER-based study and a local hospital based study from China.

Prostate cancer (PCa) is the leading cause of cancer-related death among men worldwide. Knowledge of the prognostic factors of PCa and the bone metastasis pattern of patients would be helpful for patients and doctors. The data of 177,255 patients with prostate cancer diagnosed between 2010 and 2013 with at least five years of follow-up were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Multivariate Cox regression analysis was used to determine the predictive value of patients' characteristics for survival after adjusting for other variates. Multivariate logistic regression analysis was used to evaluate the odds ratio of bone metastasis in PCa patients. The predictive value of age, race, marital status, and tumor characteristics were compared. The survival of patients with different socioeconomic statuses and bone metastasis statuses was compared by Kaplan-Meier analysis. A total of 1,335 patients with prostate cancer diagnosed between 2009 and 2015 were enrolled from the Second Affiliated Hospital of Zhejiang University School of Medicine. The survival of patients with different prostate-specific antigen (PSA) levels, Gleason scores, marital statuses and bone metastasis statuses was compared by Kaplan-Meier analysis. In SEER database, 96.74% of patients were 50 years of age or older. Multivariate Cox analysis revealed that for PCa patients, age at presentation, older age, single marital status, lower socioeconomic status, higher PSA level, T1 and N0 stage, and bone metastasis were independent risk factors for increased mortality. Multivariate logistic regression analysis revealed that patients who were married, were living in urban areas, had lower PSA levels, underwent surgery, and radiation had lower OR factors for bone metastasis. Asian or Pacific Islander, better socioeconomic status, lived in urban areas, married marital status, lower PSA levels and lower Gleason scores were better prognostic factors in PCa. Additionally, patients with single or divorced marital status, who were living in rural places had higher PSA levels, and T1 and N0 stages have a high OR for bone metastasis.

Transplantation Strategies for Spinal Cord Injury Based on Microenvironment Modulation.

Spinal cord injury (SCI) is different from peripheral nerve injury; it results in devastating and permanent damage to the spine, leading to severe motor, sensory and autonomic dysfunction. SCI produces a complex microenvironment that can result in hemorrhage, inflammation and scar formation. Not only does it significantly limit regeneration, but it also challenges a multitude of transplantation strategies. In order to promote regeneration, researchers have recently begun to focus their attention on strategies that manipulate the complicated microenvironment produced by SCI. And some have achieved great therapeutic effects. Hence, reconstructing an appropriate microenvironment after transplantation could be a potential therapeutic solution for SCI. In this review, first, we aim to summarize the influential compositions of the microenvironment and their different effects on regeneration. Second, we highlight recent research that used various transplantation strategies to modulate different microenvironments produced by SCI in order to improve regeneration. Finally, we discuss future transplantation strategies regarding SCI.

Micro Fragmented Adipose Tissue Promotes the Matrix Synthesis Function of Nucleus Pulposus Cells and Regenerates Degenerated Intervertebral Disc in a Pig Model.

Intervertebral disc (IVD) degeneration and consequent lower back pain is a common disease. Micro fragmented adipose tissue (MFAT) is promising for a wide range of applications in regenerative medicine. In this study, MFAT was isolated by a nonenzymatic method and co-cultured with nucleus pulposus cells (NPCs) using an indirect co-culture system in vitro. A pig disc degeneration model was used to investigate the regenerative effect of MFAT on degenerated IVDs in vivo. The mRNA expression of Sox9, Acan, and Col2 in NPCs was significantly increased, while no significant increase was observed in the mRNA expression of proinflammatory cytokine genes after the NPCs were co-cultured with MFAT. Nucleus pulposus (NP)-specific markers were increased in MFAT cells after co-culture with NPCs. After injection of MFAT, the disc height, water content, extracellular matrix, and structure of the degenerated NP were significantly improved. MFAT promoted the matrix synthesis function of NPCs, and NPCs stimulated the NP-like differentiation of MFAT cells. In addition, MFAT also partly regenerated degenerated IVDs in the pig model.

Scar Tissue-Targeting Polymer Micelle for Spinal Cord Injury Treatment.

Spinal cord injury (SCI) is a devastating disorder, leading to permanent motor and sensory deficit. Despite recent advances in neurosciences, the treatment efficacy on SCI patients remains unsatisfactory, mainly due to the poor accumulation, short retention, and lack of controlled release of therapeutics in lesion tissue. Herein, an injured spinal cord targeting prodrug polymer micelle is built. An esterase-responsive bond is used to link apocynin (APO) monomer, because of the enhanced esterase activity found in microglia cells after activation, which ensures a controlled degradation of APO prodrug (Allyloxypolyethyleneglycol-b-poly [2-(((4-acetyl-2-methoxyphenoxy)carbonyl)oxy)ethyl methacrylate], APEG-PAPO or PAPO) by activated microglia cells. A scar tissue-homing peptide (cysteine-alanine-glutamine-lysine, CAQK) is introduced to the PAPO to endow the polymer micelle the lesion tissue-targeting ability. As a result, this CAQK-modified prodrug micelle (cPAM) exhibits an improved accumulation and prolonged retention in lesion tissue compared to the control micelle. The cPAM also leads to superior tissue protection and sustained motor function recovery than the control groups in a mouse model of SCI. In conclusion, the cPAM induces an effective treatment of SCI by the lesion tissue specific delivery of the prodrug polymer via its robust scar binding effect, making the scar tissue a drug releasing platform for sustained treatment of SCI.

Magnetic Resonance Imaging Study of Oblique Corridor and Trajectory to L1-L5 Intervertebral Disks in Lateral Position.

OBJECTIVE: This study investigated the retroperitoneal oblique corridor and trajectory of L1-L5 as the lateral surgical access to the intervertebral disks in the Chinese population and detected the potential relationship between the corridor or trajectory and vertebral parameters, including disk axis, psoas muscle, and retroperitoneal vessel. METHODS: Seventy magnetic resonance imaging studies performed from January 2017 to January 2019 were investigated. The oblique corridor was defined as the distance between the left lateral border of the retroperitoneal vessel and the anterior border of psoas. The trajectory was defined as the distance between the retroperitoneal vessel and lumbar plexus. RESULTS: The oblique corridor analysis to L1-L5 disks have the following mean distances: L1-2 13.36 mm, L2-3 13.36 mm, L3-4 12.37 mm, and L4-5 10.36 mm. There was no difference in the L1-L5 corridor between genders. And the position of retroperitoneal vessel was negatively correlated with the corridor width. The trajectory measurements to L1-L5 disks have the following mean distances: L1-2 27.44 mm, L2-3 30.86 mm, L3-4 30.73 mm, and L4-5 24.36 mm. Moreover, the vertebral parameters, including the disk axis and psoas muscle, were positively correlated with the trajectory width. Otherwise, the position of retroperitoneal vessel was negatively correlated with the trajectory width. CONCLUSIONS: Compared with previous studies, the safe surgical area of the Chinese is generally smaller than that of Caucasian. The position of the retroperitoneal vessel is the vital potential to limit the corridor and trajectory. Preoperative assessment of vertebral parameters, especially vascular structure, is essential for planning surgical process.

Small Molecule-Based Strategy Promotes Nucleus Pulposus Specific Differentiation of Adipose-Derived Mesenchymal Stem Cells.

Adipose tissue-derived mesenchymal stem cells (ADSCs) are promising for regenerating degenerated intervertebral discs (IVDs), but the low efficiency of nucleus pulposus (NP)-specific differentiation limits their clinical applications. The Sonic hedgehog (Shh) signaling pathway is important in NP-specific differentiation of ADSCs, and Smoothened Agonist (SAG) is a highly specific and effective agonist of Shh signaling. In this study, we proposed a new differentiation strategy with the use of the small molecule SAG. The NP-specific differentiation and extracellular matrix (ECM) synthesis of ADSCs were measured in vitro , and the regenerative effects of SAG pretreated ADSCs in degenerated IVDs were verified in vivo . The results showed that the combination of SAG and transforming growth factor-ß3 (TGF-ß3) is able to increase the ECM synthesis of ADSCs. In addition, the gene and protein expression levels of NP-specific markers were increased by treatment with SAG and TGF-ß3. Furthermore, SAG pretreated ADSCs can also improve the disc height, water content, ECM content, and structure of degenerated IVDs in vivo . Our new differentiation scheme has high efficiency in inducing NP-specific differentiation of ADSCs and is promising for stem cell-based treatment of degenerated IVDs.

Wogonin mitigates intervertebral disc degeneration through the Nrf2/ARE and MAPK signaling pathways.

Intervertebral disc degeneration (IVDD) is a prevalent disease characterized by the progressive loss of the extracellular matrix in the local nucleus pulposus region. Metalloproteinases and pro-inflammatory cytokines play an important role in this process. Thus, anti-inflammatory strategies are an important component of IVDD treatment. Wogonin, a naturally existing monoflavonoid, has been reported to have potential anti-inflammatory effects in some inflammatory diseases. Hence, in our present study we investigated the protective effects and potential mechanisms of wogonin in rat nucleus pulposus cells that had been treated with interleukin-1beta (IL-1ß) to induce severe IVDD. An in vivo rat caudal vertebrae needle-stab model was also designed and its validity was evaluated as an IVDD model. The results demonstrated that wogonin suppressed IL-1ß-induced inflammatory mediators (iNOS, IL-6 and COX2) and matrix-degrading proteinases (MMP1, MMP3, MMP13 and ADAMTS4). Wogonin also upregulated some of the key components of the extracellular matrix, such as collagen II. Furthermore, we discovered that wogonin exerted anti-inflammatory effects by activating the Nrf2/HO-1-SOD2-NQO1-GCLC signaling axis. Moreover, the IL-1ß-induced stimulation of the MAPK signaling pathway was reversed by wogonin treatment. The in vivo MRI and histological results also revealed that wogonin protected the nucleus pulposus from the progression of IVDD. Therefore, wogonin may be a potential agent for the treatment of IVDD.