Osteoporosis of the vertebra and osteochondral remodeling of the endplate causes intervertebral disc degeneration in ovariectomized mice

Vitamin D delays intervertebral disc degeneration and improves bone quality in ovariectomized rats

Known to be involved in bone-cartilage metabolism, Vitamin D (VD) may play a role in human's disc pathophysiology. Given that postmenopausal women are prone to suffer VD deficiency and intervertebral disc degeneration (IDD), this study is intended to investigate whether VD can delay IDD in ovariectomized rats by improving bone microstructure and antioxidant stress. Female Sprague-Dawley rats were randomly allocated into four groups: sham, oophorectomy (OVX)+VD deficiency (VDD), OVX, and OVX+VD supplementation (VDS). In vivo, after a 6-month intervention, imaging and pathology slice examinations showed that IDD induced by OVX was significantly alleviated in VDS and deteriorated by VDD. The expressions of aggrecan and Collagen II in intervertebral disc were reduced by OVX and VDD, and elevated by VDS. Compared with the OVX+VDD and OVX group vertebrae, OVX+VDS group vertebrae showed significantly improved endplate porosity and lumbar bone mineral density with increased percent bone volume and trabecular thickness. Furthermore, 1α,25(OH)2D3 restored the redox balance (total antioxidant capacity, ratio of oxidized glutathione/glutathione) in the disc. The cocultivation of 1α,25(OH)2D3 and nucleus pulposus cells (NPCs) was conducted to observe its potential ability to resist excessive oxidative stress damage induced by H2O2. In vitro experiments revealed that 1α,25(OH)2D3 reduced the senescence, apoptosis, and extracellular matrix degradation induced by H2O2 in NPCs. In conclusion, VDS exhibits protective effects in OVX-induced IDD, partly by regulating the redox balance and preserving the microstructure of endplate. This finding provides a new idea for the prevention and treatment of IDD.

Effect of patient-specific factors on regeneration in lumbar spine at healthy disc and total disc replacement. Computer simulation

BACKGROUND AND OBJECTIVE

Degenerative diseases of the spine have a negative impact on the quality of life of patients. This study presents the results of numerical modelling of the mechanical behaviour of the lumbar spine with patient-specific conditions at physiological loads. This paper aims to numerically study the influence of degenerative changes in the spine and the presence of an endoprosthesis on the creation of conditions for tissue regeneration.

METHODS

A numerical model of the mechanical behaviour of lumbar spine at healthy and after total disc replacement under low-energy impacts equivalent to physiological loads is presented. The model is based on the movable cellular automaton method (discrete elements), where the mechanical behaviour of bone tissue is described using the Biot poroelasticity accounting for the presence and transfer of interstitial biological fluid. The nutritional pathways of the intervertebral disc in cases of healthy and osteoporotic bone tissues were predicted based on the analysis of the simulation results according to the mechanobiological principles.

RESULTS

Simulation of total disc replacement showed that osseointegration of the artificial disc plates occurs only in healthy bone tissue. With total disc replacement in a patient with osteoporosis, there is an area of increased risk of bone resorption in the near-contact area, approximately 1 mm wide, around the fixators. Dynamic loads may improve the osseointegration of the implant in pathological conditions of the bone tissue.

CONCLUSIONS

The results obtained in the case of healthy spine and osteoporotic bone tissues correspond to the experimental data on biomechanics and possible methods of IVD regeneration from the position of mechanobiological principles. The results obtained with an artificial disc (with keel-type fixation) showed that the use of this type of endoprosthesis in healthy bone tissues allows to reproduce the function of the natural intervertebral disc and does not contribute to the development of neoplastic processes. In the case of an artificial disc with osteoporosis of bone tissues, there is a zone with increased risk of tissue resorption and development of neoplastic processes in the area near the contact of the implant attachment. This circumstance can be compensated by increasing the loading level.

New evidence on the controversy over the correlation between vertebral osteoporosis and intervertebral disc degeneration: a systematic review of relevant animal studies

OBJECTIVE

The effect of vertebral osteoporosis on disc degeneration remains controversial. The aim of this study was to conduct a systematic review and meta-analysis of relevant animal studies to shed more light on the effects and mechanisms of vertebral osteoporosis on disc degeneration and to promote the resolution of the controversy.

METHODS

The PubMed, Cochrane Library, and Embase databases were searched for studies that met the inclusion criteria. Basic information and data were extracted from the included studies and data were analyzed using STATA 15.1 software. This study was registered on INPLASY with the registration number INPLASY202370099 and https://doi.org/10.37766/inplasy2023.7.0099 .

RESULTS

A total of 13 studies were included in our study. Both animals, rats and mice, were covered. Meta-analysis results showed in disc height index (DHI) (P < 0.001), histological score (P < 0.001), number of osteoblasts in the endplate (P = 0.043), number of osteoclasts in the endplate (P < 0.001), type I collagen (P < 0.001), type II collagen (P < 0.001), aggrecan (P < 0.001), recombinant a disintegrin and metalloproteinase with thrombospondin-4 (ADAMTS-4) (P < 0.001), matrix metalloproteinase-1 (MMP-1) (P < 0.001), MMP-3 (P < 0.001), MMP-13 (P < 0.001), the difference between the osteoporosis group and the control group was statistically significant. In terms of disc volume, the difference between the osteoporosis group and the control group was not statistically significant (P = 0.459).

CONCLUSION

Our study shows that vertebral osteoporosis may exacerbate disc degeneration. Abnormal bone remodeling caused by vertebral osteoporosis disrupts the structural integrity of the endplate, leading to impaired nutrient supply to the disc, increased expression of catabolic factors, and decreased levels of type II collagen and aggrecan may be one of the potential mechanisms.

Stepwise reduction of bony density in patients induces a higher risk of annular tears by deteriorating the local biomechanical environment

BACKGROUND CONTEXT

The relationship between osteoporosis and intervertebral disc degeneration (IDD) remains unclear. Considering that annular tear is the primary phenotype of IDD in the lumbar spine, the deteriorating local biomechanical environment may be the main trigger for annular tears.

PURPOSE

To investigate whether poor bone mineral density (BMD) in the vertebral bodies may increase the risk of annular tears via the degradation of the local biomechanical environment.

STUDY DESIGN

This study was a retrospective investigation with relevant numerical mechanical simulations.

PATIENT SAMPLE

A total of 64 patients with low back pain (LBP) and the most severe IDD in the L4-L5 motion segment were enrolled.

OUTCOME MEASURES

Annulus integration status was assessed using diffusion tensor fibre tractography (DTT). Hounsfield unit (HU) values of adjacent vertebral bodies were employed to determine BMD. Numerical simulations were conducted to compute stress values in the annulus of models with different BMDs and body positions.

METHODS

The clinical data of the 64 patients with low back pain were collected retrospectively. The BMD of the vertebral bodies was measured using the HU values, and the annulus integration status was determined according to DTT. The data of the patients with and without annular tears were compared, and regression analysis was used to identify the independent risk factors for annular tears. Furthermore, finite element models of the L4-L5 motion segment were constructed and validated, followed by estimating the maximum stress on the post and postlateral interfaces between the superior and inferior bony endplates (BEPs) and the annulus.

RESULTS

Patients with lower HU values in their vertebral bodies had significantly higher incidence rates of annular tears, with decreased HU values being an independent risk factor for annular tears. Moreover, increased stress on the BEP-annulus interfaces was associated with a stepwise reduction of bony density (ie, elastic modulus) in the numerical models.

CONCLUSIONS

The stepwise reduction of bony density in patients results in a higher risk of annular tears by deteriorating the local biomechanical environment. Thus, osteoporosis should be considered to be a potential risk factor for IDD biomechanically.

Roles of organokines in intervertebral disc homeostasis and degeneration

The intervertebral disc is not isolated from other tissues. Recently, abundant research has linked intervertebral disc homeostasis and degeneration to various systemic diseases, including obesity, metabolic syndrome, and diabetes. Organokines are a group of diverse factors named for the tissue of origin, including adipokines, osteokines, myokines, cardiokines, gastrointestinal hormones, and hepatokines. Through endocrine, paracrine, and autocrine mechanisms, organokines modulate energy homeostasis, oxidative stress, and metabolic balance in various tissues to mediate cross-organ communication. These molecules are involved in the regulation of cellular behavior, inflammation, and matrix metabolism under physiological and pathological conditions. In this review, we aimed to summarize the impact of organokines on disc homeostasis and degeneration and the underlying signaling mechanism. We focused on the regulatory mechanisms of organokines to provide a basis for the development of early diagnostic and therapeutic strategies for disc degeneration.

Strontium ranelate retards disc degradation and improves endplate and bone micro-architecture in ovariectomized rats with lumbar fusion induced - Adjacent segment disc degeneration

Objectives

Adjacent segment disc degeneration (ASDD) is one of the long-term sequelae of spinal fusion, which is more susceptible with osteoporosis. As an anti-osteoporosis drug, strontium ranelate (SR) has been reported to not only regulate bone metabolism but also cartilage matrix formation. However, it is not yet clear whether SR has a reversal or delaying effect on fusion-induced ASDD in a model of osteoporosis.

Materials and methods

Fifth three-month-old female Sprague-Dawley rats that underwent L4-L5 posterolateral lumbar fusion (PLF) with spinous-process wire fixation 4 weeks after bilateral ovariectomy (OVX) surgery. Animals were administered vehicle (V) or SR (900 mg/kg/d) orally for 12 weeks post-PLF as follows: Sham+V, OVX + V, PLF + V, OVX + PLF + V, and OVX + PLF + SR. Manual palpation and X-ray were used to evaluate the state of lumbar fusion. Adjacent-segment disc was assessed by histological (VG staining and Scoring), histomorphometry (Disc Height, MVD, Calcification rate and Vascular Bud rate), immunohistochemical (Col-II, Aggrecan, MMP-13, ADAMTS-4 and Caspase-3), and mRNA analysis (Col-I, Col-II, Aggrecan, MMP-13 and ADAMTS-4). Adjacent L6 vertebrae microstructures were evaluated by microcomputed tomography.

Results

Manual palpation and radiographs showed clear evidence of the fused segment's immobility. After 12 weeks of PLF surgery, a fusion-induced ASDD model was established. Low bone mass caused by ovariectomy can significantly exacerbate ASDD progression. SR exerted a protective effect on adjacent segment intervertebral disc with the underlying mechanism possibly being associated with preserving bone mass to prevent spinal instability, maintaining the functional integrity of endplate vascular microstructure, and regulating matrix metabolism in the nucleus pulposus and annulus fibrosus.

Discussion

Anti-osteoporosis medication SR treatments not only maintain bone mass and prevent fractures, but early intervention could also potentially delay degenerative conditions linked to osteoporosis. Taken together, our results suggested that SR might be a promising approach for the intervention of fusion-induced ASDD with osteoporosis.

TGF-β1 Inhibits Osteoclast Differentiation and Abnormal Angiogenesis in Intervertebral Disc Degeneration: Evidence from RNA Sequencing and Animal Studies

OBJECTIVE

Mechanisms involved in developing intervertebral disc degeneration (IDD) are poorly understood, thus making developing effective therapies difficult. This study aimed to suggest a possible molecular mechanism, based on transcriptome sequencing-identified transforming growth factor (TGF-β), underlying the effects on bone homeostasis in IDD.

METHODS

A mouse model for IDD was established. Transcriptome sequencing of nucleus pulposus tissue from mice (n = 3) identified differentially expressed mRNAs and key genes impacting bone homeostasis. A protein-protein interaction network pinpointed core genes. GO and KEGG analysis revealed gene functions. Expression levels of TGF-β1, tartrate-resistant acid phosphatase (TRAP), and cathepsin K (CTSK) were measured. Micro-CT evaluated vertebral structures and vascular imaging. Western Blot measured expression levels of Vegf, Opn, MMP3, and MMP13. Safranin O-Fast Green and TRAP staining were performed on intervertebral discs and endplates.

RESULTS

Transcriptomic analysis found 1790 differentially expressed mRNAs in IDD mice. Twenty-eight genes related to bone homeostasis in IDD were identified. TGF-β1 was confirmed as the core gene. GO and KEGG showed TGF-β1 regulates osteoclast markers like CTSK and TRAP through pathways including NF-κB and MAPK. Experimental validation revealed lower TGF-β1 expression in IDD mice than controls, and increased TRAP and CTSK expression. Micro-CT showed decreased bone mass and intervertebral disc space in IDD mice. Vascular imaging showed increased vascular volume in IDD cartilaginous endplates. Western blot displayed increased VEGF and OPN levels, but decreased MMP3 and MMP13 in IDD mice. Safranin O-fast green staining revealed severe IDD degeneration. However, TGF-β1 injection improved bone parameters in IDD mice. In vitro experiments confirmed TGF-β1 inhibits bone marrow macrophages differentiation into osteoclasts.

CONCLUSION

From our data, we conclude that TGF-β1 repressed osteoclast differentiation and aberrant bone-associated angiogenesis in cartilage endplates (EPs) to alleviate IDD, which may be instrumental for the therapeutic targeting of IDD.

Does vertebral osteoporosis delay or accelerate lumbar disc degeneration? A systematic review

The effect of vertebral osteoporosis on disc degeneration is still debated. The purpose of this study was to provide a systematic review of studies in this area to further reveal the relationship between the two. Relevant studies were searched in electronic databases, and studies were screened according to inclusion and exclusion criteria, and finally, basic information of the included studies was extracted and summarized. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A total of 34 publications spanning 24 years were included in our study. There were 19 clinical studies, including 12 prospective studies and 7 retrospective studies. Of these, 7 considered vertebral osteoporosis to be positively correlated with disc degeneration, 8 considered them to be negatively correlated, and 4 considered them to be uncorrelated. Two cadaveric studies were included, one considered the two to be negatively correlated and one considered them not to be correlated. Seven animal studies were included, of which five considered a positive correlation between vertebral osteoporosis and disc degeneration and two considered a negative correlation between the two. There were also 6 studies that used anti-osteoporosis drugs for intervention, all of them were animal studies. Five of them concluded that vertebral osteoporosis was positively associated with disc degeneration, and the remaining one concluded that there was no correlation between the two. Our systematic review shows that the majority of studies currently consider an association between vertebral osteoporosis and disc degeneration, but there is still a huge disagreement whether this association is positive or negative. Differences in observation time and follow-up time may be one of the reasons for the disagreement. A large number of clinical and basic studies are still needed in the future to further explore the relationship between the two.

Spatially multicellular variability of intervertebral disc degeneration by comparative single-cell analysis

Previous studies have revealed cellular heterogeneity in intervertebral discs (IVDs). However, the cellular and molecular alteration patterns of cell populations during degenerative progression remain to be fully elucidated. To illustrate the cellular and molecular alteration of cell populations in intervertebral disc degeneration (IDD), we perform single cell RNA sequencing on cells from four anatomic sites of healthy and degenerative goat IVDs. EGLN3+ StressCs, TGFBR3+ HomCs and GPRC5A+ RegCs exhibit the characteristics associated with resistance to stress, maintaining homeostasis and repairing, respectively. The frequencies and signatures of these cell clusters fluctuate with IDD. Notably, the chondrogenic differentiation programme of PROCR+ progenitor cells is altered by IDD, while notochord cells turn to stemness exhaustion. In addition, we characterise CAV1+ endothelial cells that communicate with chondrocytes through multiple signalling pathways in degenerative IVDs. Our comprehensive analysis identifies the variability of key cell clusters and critical regulatory networks responding to IDD, which will facilitate in-depth investigation of therapeutic strategies for IDD.

Low back pain and osteoarthritis pain: a perspective of estrogen

Low back pain (LBP) is the world's leading cause of disability and is increasing in prevalence more rapidly than any other pain condition. Intervertebral disc (IVD) degeneration and facet joint osteoarthritis (FJOA) are two common causes of LBP, and both occur more frequently in elderly women than in other populations. Moreover, osteoarthritis (OA) and OA pain, regardless of the joint, are experienced by up to twice as many women as men, and this difference is amplified during menopause. Changes in estrogen may be an important contributor to these pain states. Receptors for estrogen have been found within IVD tissue and nearby joints, highlighting the potential roles of estrogen within and surrounding the IVDs and joints. In addition, estrogen supplementation has been shown to be effective at ameliorating IVD degeneration and OA progression, indicating its potential use as a therapeutic agent for people with LBP and OA pain. This review comprehensively examines the relationship between estrogen and these pain conditions by summarizing recent preclinical and clinical findings. The potential molecular mechanisms by which estrogen may relieve LBP associated with IVD degeneration and FJOA and OA pain are discussed.

Feasibility Study of 3D FACT and IVIM Sequences in the Evaluation of Female Osteoporosis

BACKGROUND

The aim of this study is to search for the predictive value of 3D fat analysis and calculation technique (FACT) and intravoxel incoherent motion (IVIM) parameters in identifying osteoporosis in women.

METHODS

We enrolled 48 female subjects who underwent 3.0 T MRI, including 3D FACT and IVIM sequences. Bone mineral density (BMD) values and Fracture Risk Assessment (FRAX) scores were obtained. Proton density fat fraction (PDFF) in the bone marrow and the real diffusion (D) value of intervertebral discs were measured on 3D FACT and IVIM images, respectively. Accuracy and bias were assessed by linear regression analysis and Bland-Altman plots. Intraclass correlation coefficients were used to assess the measurements' reproducibility. Spearman's rank correlation was applied to explore the correlation. MRI-based parameters were tested for significant differences among the three groups using ANOVA analyses. A receiver operating characteristic (ROC) analysis was performed.

RESULTS

The PDFF of the vertebral body showed a negative correlation with BMD (R = -0.393, p = 0.005) and a positive correlation with the FRAX score (R = 0.706, p < 0.001). The D value of intervertebral discs showed a positive correlation with BMD (R = 0.321, p = 0.024) and a negative correlation with the FRAX score (R = -0.334, p = 0.019). The area under the curve values from the ROC analysis showed that the 3D FACT and IVIM sequences could accurately differentiate between normal and osteoporosis (AUC = 0.88 using the PDFF; AUC = 0.77 using the D value). The PDFF value demonstrated a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 78.6%, 89.5%, 84.6%, and 85.0%, respectively, in its ability to predict osteoporosis. The D value had a sensitivity, specificity, PPV, and NPV of 63.16%, 92.9%, 65.0%, and 77.8%, respectively, for predicting osteoporosis.

CONCLUSIONS

The 3D FACT- and IVIM-measured PDFF and D values are promising biomarkers in the assessment of bone quality and fracture risk.

HTRA1 from OVX rat osteoclasts causes detrimental effects on endplate chondrocytes through NF-κB

Endplate osteochondritis is considered one of the major causes of intervertebral disc degeneration (IVDD) and low back pain. Menopausal women have a higher rate of endplate cartilage degeneration than similarly aged men, but the related mechanisms are still unclear. Subchondral bone changes, mainly mediated by osteoblasts and osteoclasts, are considered an important reason for the degeneration of cartilage. This work explored the role of osteoclasts in endplate cartilage degeneration, as well as its underlying mechanisms. A rat ovariectomy (OVX) model was used to induce estrogen deficiency. Our experiments indicated that OVX significantly promoted osteoclastogenesis and anabolism and catabolism changes in endplate chondrocytes. OVX osteoclasts cause an imbalance between anabolism and catabolism in endplate chondrocytes, as shown by a decrease in anabolic markers such as Aggrecan and Collagen II, and an increase in catabolic markers such as a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) and matrix metalloproteinases (MMP13). Osteoclasts were also confirmed in this study to be able to secrete HtrA serine peptidase 1 (HTRA1), which resulted in increased catabolism in endplate chondrocytes through the NF-κB pathway under estrogen deficiency. This study demonstrated the involvement and mechanism of osteoclasts in the anabolism and catabolism changes of endplate cartilage under estrogen deficiency, and proposed a new strategy for the treatment of endplate osteochondritis and IVDD by targeting HTRA1.

Mechanism of YAP1 in the senescence and degeneration of endplate chondrocytes induced by intermittent cyclic mechanical tension

BACKGROUND

This study aimed to investigate the potential mechanism of YAP1 in the senescence and degeneration of endplate chondrocytes induced by intermittent cyclic mechanical tension (ICMT).

METHODS

According to the Pfirrmann grade evaluation classification, 30 human endplate cartilage tissues were divided into the lumbar vertebra fracture (LVF) group and lumbar disc herniation (LDH) group. Then, quantitative reverse transcription polymerase chain reaction, western blot, flow cytometry, hematoxylin-eosin staining, and senescence-associated β-galactosidase staining were performed. The difference in extracellular matrix expression between LVF and LDH endplate cartilage was detected. Second, the effect of ICMT on endplate chondrocytes degeneration was observed. Finally, the key regulatory role of YAP1 in ICMT-induced endplate cartilage degeneration was further verified.

RESULTS

In degraded human endplate cartilage and tension-induced degraded endplate chondrocytes, the expression of YAP1, COL-2A, and Sox9 was decreased. Conversely, the expression of p53 and p21 was increased. By regulating YAP1 in vivo and in vitro, we can achieve alleviation of ICMT-induced senescence of endplate chondrocytes and effective treatment of disc degeneration.

CONCLUSIONS

ICMT could induce senescence and degeneration of endplate chondrocytes, and ICMT-induced senescence and degeneration of endplate chondrocytes could be alleviated by regulating YAP1 expression.

The volume of extruded materials is correlated with neurologic severity in small-breed dogs with type I thoracolumbar intervertebral disk herniation

OBJECTIVE

To assess whether the volume of extruded materials is correlated with neurologic severity in dogs with type I thoracolumbar intervertebral disk herniation (TL-IVDH).

ANIMALS

70 client-owned small-breed dogs with type I TL-IVDH diagnosed between July 1, 2016, and June 30, 2018.

PROCEDURES

For this retrospective cohort study, the medical records of 70 dogs with surgically confirmed type I TL-IVDH were reviewed. The volume and height of the intervertebral disk and the area of the maximal transverse compressed spinal cord were measured using CT myelographic images. For each dog, the volume of the disk immediately cranial to the herniated disk was an internal control. Dogs were grouped on the basis of grade of neurologic severity.

RESULTS

Preoperative grades of neurologic severity were grade 2 in 7 (10%) dogs, grade 3 in 16 (23%) dogs, grade 4 in 28 (40%) dogs, and grade 5 in 19 (27%) dogs. The total volume of the affected intervertebral disks was significantly larger than the internal control. Weak positive correlation was found between the volume of the extruded materials into the vertebral canal and the grade of neurologic severity.

CLINICAL RELEVANCE

Our findings indicated that the total volume of the affected intervertebral disks is larger in dogs with type I TL-IVDH, and the volume of the extruded materials into the vertebral canal is weakly correlated with the neurologic severity.

Constitutive and conditional gene knockout mice for the study of intervertebral disc degeneration: Current status, decision considerations, and future possibilities

There have been an increasing number of patients with degenerative disc diseases due to the aging population. In light of this, studies on the pathogenesis of intervertebral disc degeneration have become a hot topic, and gene knockout mice have become a valuable tool in this field of research. With the development of science and technology, constitutive gene knockout mice can be constructed using homologous recombination, zinc finger nuclease, transcription activator-like effector nuclease technology and clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) system, and conditional gene knockout mice can be constructed using the Cre/LoxP system. The gene-edited mice using these techniques have been widely used in the studies on disc degeneration. This paper reviews the development process and principles of these technologies, functions of the edited genes in disc degeneration, advantages, and disadvantages of different methods and possible targets of the specific Cre recombinase in intervertebral discs. Recommendations for the choice of suitable gene-edited model mice are presented. At the same time, possible technological improvements in the future are also discussed.

Red Light-Mediated Photoredox Catalysis Triggers Nitric Oxide Release for Treatment of Cutibacterium Acne Induced Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) has been known as a highly prevalent and disabling disease, which is one of the main causes of low back pain and disability. Unfortunately, there is no effective cure to treat this formidable disease, and surgical interventions are typically applied. Herein, we report that the local administration of nitric oxide (NO)-releasing micellar nanoparticles can efficiently treat IVDD associated with Modic changes in a rat model established by infection with Cutibacterium acnes (C. acnes). By covalent incorporation of palladium(II) meso-tetraphenyltetrabenzoporphyrin photocatalyst and coumarin-based NO donors into the core of micellar nanoparticles, we demonstrate that the activation of the UV-absorbing coumarin-based NO donors can be achieved under red light irradiation via photoredox catalysis, although it remains a great challenge to implement photoredox catalysis reactions in biological conditions due to the complex microenvironments. Notably, the local delivery of NO can not only efficiently eradicate C. acnes pathogens but also inhibit the inflammatory response and osteoclast differentiation in the intervertebral disc tissues, exerting antibacterial, anti-inflammatory, and antiosteoclastogenesis effects. This work provides a feasible means to efficiently treat IVDD by the local administration of NO signaling molecules without resorting to a surgical approach.

Examination of the microstructures of the lower cervical facet based on micro-computed tomography: A cadaver study

The cervical facet has complicated 3D microstructures and inhomogeneities. The cervical facet joint, which also participates in the formation, plays a certain role in regulating and limiting the movement of the spine. Correct identification and evaluation of its microstructure can help in the diagnosis of orthopedic disease and predict early phases of fracture risk. To evaluate the safety of the cervical spine by measuring and analyzing the microstructures and morphometric parameters of bone trabeculae in the normal cervical facet with high-resolution 3D micro-computed tomography. Thirty-one sets of C3 to C7 lower cervical vertebrae (155 vertebrae) were scanned using micro-computed tomography. The morphological characteristics and direction of trabecular bone in the facet of the lower cervical vertebrae were observed by selecting and rebuilding the areas of interest, and the changes in the microstructure of the areas of interest were calculated to reveal the structural characteristics and weak areas. Images indicated an ossified center between the superior and inferior articular processes of the lower cervical spine. The cellular bone trabeculae of the articular process had complex reticular microstructures. The trabecular bone plate near the cortical bone was lamellar and relatively dense, and it extended around and transformed into a network structure, and then into the rod-shaped trabecular bone. The rod-shaped trabeculae converged with the plate-shaped trabeculae with only 1 to 2 layers surrounding the trabeculae cavity. Statistical results of the morphological parameters of the trabecular bone showed that trabecular bone volume fraction values were significantly higher for C7 than for C3 to C6 (P < .05). There were significant differences between C7 and C3 to C5 and between C6 and C4 in bone surface area/bone volume (P < .05). There was a significant difference between C7 and C3 to C6 in trabecular bone thickness values (P < .05). The degree of anisotropy value was significantly smaller for C3 than for C6 and C7 (P < .05). The changes in the C3 to C7 microstructure were summarized in this study. The loading capacity and stress of the C7 articular process tended to be limited, and the risk of injury tended to be higher for the C7 articular process.

Vertebral endplate defects are associated with bone mineral density in lumbar degenerative disc disease

PURPOSE

Evidence has shown that lumbar vertebral endplate defects are clinically relevant and closely related to disc degeneration, but the relationship between endplate defects and bone mineral density (BMD) remains unclear. This study aimed to explore the association between endplate defects and BMD-related values in patients with lumbar degenerative disc disease (LDD).

METHODS

Three hundred and twenty-five Chinese adult subjects diagnosed with LDD underwent dual energy X-ray absorptiometry. Endplate defects were classified using lumbar MRI. Groups were subdivided based on the occurrence rates of defect endplates. BMD at the lumbar vertebral and bilateral femur necks was compared between groups, and the association between endplate defects and lumbar BMD-related values was analyzed and adjusted for confounders including age, sex, serum levels of 25-hydroxy vitamin D (25(OH)D), calcium (Ca) and phosphorus (P).

RESULTS

Of 325 patients and 3250 endplates, 59.72% had defects, and 188 patients were divided into the higher defect rate group (occurrence rate > 50%). The higher defect rate group was associated with older age, more common postmenopausal females, higher osteoporosis rates and lower serum Ca and P levels. Lumbar BMD was greater than that at bilateral femur necks and was not equal to osteoporosis diagnosis. Endplate defects were more prevalent in lower segments. The occurrence of endplate defects was positively associated with lumbar BMD-related values in the partial correlation analysis. The association between endplate defects and lumbar BMD varies for subtypes and segments, with a trend of positive association in rim and erosive subtypes after adjusting for confounders.

CONCLUSIONS

The present study demonstrated that the occurrence of endplate defects was associated with greater lumbar BMD values in patients with LDD. This association varies for different defect subtypes and segments. The results indicated that endplate defects should be taken into consideration in osteoporosis treatment to alleviate disc degeneration.

Exogenous Indian hedgehog antagonist damages intervertebral discs homeostasis in adult mice

Background

Vismodegib, as an exogenous Indian hedgehog (Ihh) antagonist, has been approved by the Food and Drug Administration (FDA) for the clinical treatment of patients with basal cell carcinoma, and previous observations implicate the potential therapeutic of vismodegib in osteoarthritis treatment. However, there is no direct evidence for the role of Ihh signaling in intervertebral discs (IVDs) homeostasis of adult mice. The aim of the present study is to assess the effect of systemic administration of Smoothened inhibitor (SMOi) - vismodegib on IVDs homeostasis during the adult stage.

Methods

The expression of glioma-associated oncogene homolog 1 (Gli1), the downstream targeting gene of Ihh signaling, in IVDs of adult mice after receiving systemic administration of SMOi was examined by immunohistochemistry. The pathological changes of vertebral bodies after SMOi treatment were evaluated by X-ray and micro-CT. The effects of SMOi on homeostasis of IVDs including cartilaginous endplates (CEP), growth plates (GP) and annulus fibrous (AF) were evaluated by histological analysis. The expressions of Aggrecan, Matrix metalloproteinase 13 (MMP13) and Runt-related transcription factor 2 (Runx2), in IVDs were also investigated by immunohistochemistry. Changes in chondrocyte apoptosis and proliferation in IVDs were evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and analyzing the expression of the cell proliferation antigen Ki-67.

Results

Systemic administration of SMOi significantly decreased the expression of Gli1 in IVDs that indicating effective inhibition of Ihh signaling. Bone mass of vertebral bodies was diminished after SMOi treatment. Moreover, IVDs degeneration (IDD) like defects including CEP sclerosis, degenerative nucleus pulposus (NP) and fissure within AF, as well as narrowed or fused GP and loss bone mass of vertebral bodies was observed in SMOi-treated mice. The severity of IDD was time-dependent with the administration of SMOi treatment after 2-8 weeks. The expressions of Aggrecan, MMP13 and Runx2 in IVDs of mice receiving SMOi treatment were significantly decreased. In addition, chondrocyte apoptosis was significantly enhanced, while chondrocyte proliferation was significantly inhibited.

Conclusions

Our study propose that systemic administration of vismodegib damages IVDs homeostasis via inhibition of Ihh signaling in adult mice. The clinical application of Ihh signaling antagonists such as vismodegib should be careful considering these side adverse.

The Translational Potential of this Article

Vismodegib as an exogenous antagonist of Ihh signaling has been approved by the FDA for the clinical treatment of patients with basal cell carcinoma. However, it is still unknown whether vismodegib will has adverse effects on the patient or animal model of IVDs cartilage homeostasis. Based on our study, systemic administration of vismodegib damages IVDs homeostasis via inhibition of Ihh signaling in adult mice and special attention should be paid to the clinical application of vismodegib.

Sex-dependent effects of multiple acute concurrent stresses on memory: a role for hippocampal estrogens

Memory disruption commonly follows chronic stress, whereas acute stressors are generally benign. However, acute traumas such as mass shootings or natural disasters—lasting minutes to hours and consisting of simultaneous physical, social, and emotional stresses—are increasingly recognized as significant risk factors for memory problems and PTSD. Our prior work has revealed that these complex stresses (concurrent multiple acute stresses: MAS) disrupt hippocampus-dependent memory in male rodents. In females, the impacts of MAS are estrous cycle-dependent: MAS impairs memory during early proestrus (high estrogens phase), whereas the memory of female mice stressed during estrus (low estrogens phase) is protected. Female memory impairments limited to high estrogens phases suggest that higher levels of estrogens are necessary for MAS to disrupt memory, supported by evidence that males have higher hippocampal estradiol than estrous females. To test the role of estrogens in stress-induced memory deficits, we blocked estrogen production using aromatase inhibitors. A week of blockade protected male and female mice from MAS-induced memory disturbances, suggesting that high levels of estrogens are required for stress-provoked memory impairments in both males and females. To directly quantify 17β-estradiol in murine hippocampus we employed both ELISA and mass spectrometry and identified significant confounders in both procedures. Taken together, the cross-cycle and aromatase studies in males and females support the role for high hippocampal estrogens in mediating the effect of complex acute stress on memory. Future studies focus on the receptors involved, the longevity of these effects, and their relation to PTSD-like behaviors in experimental models.

Anemia was associated with multilevel lumbar disc degeneration in patients with low back pain: a single-center retrospective study

PURPOSE

It has not been determined which factors were related to multilevel lumbar disc degeneration (MLDD). The objective of this study was to determine the prevalence of MLDD among symptomatic patients using the magnetic resonance imaging method. The study also aimed to clarify the associations between MLDD and suspected risk factors through a multivariate model.

METHODS

A total of 530 young and middle-aged patients, suffered from low back pain were retrospectively assessed by 2 independent observers, who used sagittal T2-weighted MR imaging. Subjects were divided into two groups, MLDD group and non-MLDD group, according to the number of degenerated discs. Demographic and radiological data included age, gender, weight, height, body mass index, smoking status, alcohol drinking, lumbar lordosis, presence of hypertension (HT), diabetes mellitus and anemia.

RESULTS

There were 309 men and 221 women with an average age of 37.5  ±  8.5 years. In general, 37.7% of patients were diagnosed with disc degeneration (DD) at more than two levels. Triple level DD was the most common pattern and was more prevalent in women (p <0.05). Using multivariate analyses, age (odds ratio [OR]: 1.14; 95% confidence interval [CI] 1.11-1.18; p <0.001), hypertension (OR: 2.67; 95% CI 1.38-5.16; p = 0.03) and anemia (OR: 3.84; 95% CI 2.03-7.28; p <0.001) were significantly associated with MLDD.

CONCLUSION

Despite the young age of this cohort, MLDD is common among patients with low back pain. A significant independent association exists between age, HT, anemia and multilevel disc degeneration in the lumbar region.

Association of bone-related biomarkers with femoral neck bone strength

BACKGROUND

Femoral neck fractures are the worst consequence of osteoporosis (OP), and its early prevention and treatment have become a public health problem. This study aims to investigate the relationship of bone-related biomarkers, femoral neck bone mineral density (BMD) and maximum load (L_max), selecting the indicator which can reflect femoral neck bone loss and reduced bone strength.

METHODS

A total of 108 patients were recruited from January 2017 to December 2019. Venous blood samples were collected from patients before total hip replacement, and femoral neck samples were collected during the surgery. Femoral neck BMD, femoral neck L_max, bone-related markers (serum levels of bone turnover markers, protein expression of type I collagen (COL-I) and osteopontin (OPN) in femoral neck) were all measured and analyzed.

RESULTS

The expression of COL-I in femoral neck were significantly decreased, whereas other markers were all significantly increased with the decreasing of femoral neck BMD and L_max (P < 0.05). Among them, serum C-terminal telopeptide of type I collagen (CTX) levels and OPN expression of femoral neck were increased in osteopenia. In multiple linear regression analysis, CTX and OPN were both negatively correlated with femoral neck BMD and L_max, and they were independent factors of femoral neck BMD and L_max, whereas COL-I was independent factor affecting L_max (P < 0.05). Besides, CTX was negatively correlated with COL-I (β = -0.275, P = 0.012) and positively correlated with OPN (β = 0.295, P = 0.003).

CONCLUSIONS

Compared with other indicators, serum CTX was more sensitive to differences in bone mass and bone strength of femoral neck, and could be considered as surrogate marker for OPN and COL-I.Early measurement of CTX could facilitate the diagnosis of osteopenia and provide a theoretical basis for delaying the occurrence of femoral neck OP and fragility fractures.

Exploring the impact of ovariectomy on hair growth: can ovariectomized mouse serve as a model for investigating female pattern hair loss in humans?

Female pattern hair loss (FPHL), a type of hair disease common in pre- and postmenopausal women, is characterized by thinning of hair to O-type, mainly at the crown. Although a mouse model of this disease has recently been established, its details are still unknown, and thus, warrants further analysis. In this study, 3 week-old and 7- to 8 week-old C57BL/6 female mice were divided into two groups: one group underwent ovariectomy (OVX), while the other underwent sham surgery. In the 3 week-old mice, the dorsal skin was collected at seven weeks of age, while in the 7- to 8 week-old mice, it was collected at 12 and 24 weeks of age. In the former group, both the pore size of the hair follicles (HFs) and diameter of the hair shaft of telogen HFs decreased upon OVX; while in the latter group, these factors increased significantly. Notably, the thickness of the dermis and subcutis increased significantly in the OVX group. It needs to be further elucidated whether OVX mouse could serve as an ideal mouse model for FPHL, but our results upon evaluation of skin thickness indicate that it could be used to establish a novel treatment for non-hair-related diseases, such as post-menopause-related skin condition.

Consolidating and re-evaluating the human disc nutrient microenvironment

Background

Despite exciting advances in regenerative medicine, cell‐based strategies for treating degenerative disc disease remain in their infancy. To maximize the potential for successful clinical translation, a more thorough understanding of the in vivo microenvironment is needed to better determine and predict how cell therapies will respond when administered in vivo.

Aims

This work aims to reflect on the in vivo nutrient microenvironment of the degenerating IVD through consolidating what has already been measured together with investigative in silico models.

Materials and Methods

This work uses in silico modeling, underpinned by more recent experimentally determined parameters of degeneration and nutrient transport from the literature, to re‐evaluate the current knowledge in terms of grade‐specific stages of degeneration.

Results

Through modeling only the metabolically active cell population, this work predicts slightly higher glucose concentrations compared to previous in silico models, while the predicted results show good agreement with previous intradiscal pH and oxygen measurements. Increasing calcification with degeneration limits nutrient transport into the IVD and initiates a build‐up of acidity; however, its effect is compensated somewhat by a reduction in diffusional distance due to decreasing disc height.

Discussion

This work advances in silico modeling through a strong foundation of experimentally determined grade‐specific input parameters. Taken together, pre‐existing measurements and predicted results suggest that metabolite concentrations may not be as critically low as commonly believed, with calcification not appearing to have a detrimental effect at stages of degeneration when cell therapies are an appropriate intervention.

Conclusion

Overall, our initiative is to provoke greater deliberation and consideration of the nutrient microenvironment when performing in vitro cell culture and cell therapy development. This work highlights urgency for robust experimental glucose measurements in healthy and degenerating IVDs, not only to validate in silico models but to significantly advance the field in fully elucidating the nutrient microenvironment and refining in vitro techniques to accelerate clinical translation.

gp130/STAT3 signaling is required for homeostatic proliferation and anabolism in postnatal growth plate and articular chondrocytes

Growth of long bones and vertebrae is maintained postnatally by a long-lasting pool of progenitor cells. Little is known about the molecular mechanisms that regulate the output and maintenance of the cells that give rise to mature cartilage. Here we demonstrate that postnatal chondrocyte-specific deletion of a transcription factor Stat3 results in severely reduced proliferation coupled with increased hypertrophy, growth plate fusion, stunting and signs of progressive dysfunction of the articular cartilage. This effect is dimorphic, with females more strongly affected than males. Chondrocyte-specific deletion of the IL-6 family cytokine receptor gp130, which activates Stat3, phenocopied Stat3-deletion; deletion of Lifr, one of many co-receptors that signals through gp130, resulted in a milder phenotype. These data define a molecular circuit that regulates chondrogenic cell maintenance and output and reveals a pivotal positive function of IL-6 family cytokines in the skeletal system with direct implications for skeletal development and regeneration.

Osteopontin, a bridge links osteoarthritis and osteoporosis

Osteoarthritis (OA) is the most prevalent joint disease characterized by degradation of articular cartilage, inflammation, and changes in periarticular and subchondral bone of joints. Osteoporosis (OP) is another systemic skeletal disease characterized by low bone mass and bone mineral density (BMD) accompanied by microarchitectural deterioration in bone tissue and increased bone fragility and fracture risk. Both OA and OP are mainly affected on the elderly people. Recent studies have shown that osteopontin (OPN) plays a vital role in bone metabolism and homeostasis. OPN involves these biological activities through participating in the proliferation, migration, differentiation, and adhesion of several bone-related cells, including chondrocytes, synoviocytes, osteoclasts, osteoblasts, and marrow mesenchymal stem cells (MSCs). OPN has been demonstrated to be closely related to the occurrence and development of many bone-related diseases, such as OA and OP. This review summarizes the role of OPN in regulating inflammation activity and bone metabolism in OA and OP. Furthermore, some drugs that targeted OPN to treat OA and OP are also summarized in the review. However, the complex mechanism of OPN in regulating OA and OP is not fully elucidated, which drives us to explore the depth effect of OPN on these two bone diseases.

Innovative Biological Treatment Methods for Degenerative Disc Disease

Low back pain is the leading cause of work absences and years lived with disability, and it is often associated with degenerative disc disease. In recent years, biological treatment approaches such as the use of growth factors, cell injections, annulus fibrosus (AF) repair, nucleus pulposus replacement, and tissue-engineered discs have been explored as means for preventing or reversing degenerative disc disease. Both animal and clinical studies have shown promising results for cell-based therapy on the grounds of its regenerative potential. Clinical data also indicate that stem cell injection is safe when appropriately performed, albeit its long-term safety and efficacy are yet to be explored. Numerous challenges also remain to be overcome, such as isolating, differentiating, and preconditioning the disc cells, as well as managing the nutrient-deficient and oxygen-deficient micromilieu of the intervertebral disc (IVD). AF repair methods including devices used in clinical trials have shown success in decreasing reherniation rates and improving overall clinical outcomes. In addition, recent studies that combined AF repair and nucleus pulposus replacement have shown improved biomechanical stability in IVDs after the combined treatment. Tissue-engineered IVDs for total disc replacement are still being developed, and future studies are necessary to overcome the challenges in their delivery, efficacy, and safety.

The Correlation of Regional Microstructure and Mechanics of the Cervical Articular Process in Adults

Purpose: Using micro-CT and finite element analysis to establish regional variation microarchitectures and correlation with mechanical properties of cervical articular facet trabecular bone to predict cervical spine security and material properties. Methods: A total of 144 cervical articular processes (each articular was separate to four region of interest (ROI), superior-anterior (SA), superior-posterior (SP), inferior-anterior (IA), and inferior-posterior (IP) regions) specimens with a volume of 5 × 5 × 5 mm³ were scanned by micro-CT, and allowable stress and other mechanical properties parameters in each region were calculated after mechanical testing, then the effectiveness was verified of finite element models by ABAQUS software. Results: Maximum and minimum values of C2–C7 articular processes and regions are C5 and C7 level, SA and SP regions for bone volume fraction (BV/TV) and trabecular thickness (Tb.Th), whose variation tendency is similar to the Young’s modulus, allowable stress, BMD, maximum force and strain. Between Young’s modulus and all microstructure parameters, especially between BV/TV, bone mineral density (BMD) and Tb.Th, had higher linear regression coefficients R² = 0.5676, 0.6382, 0.3535, respectively. BMD and yield strength, BV/TV, and allowable stress also had better regression coefficients, R² = 0.5227, 0.5259, 0.5426, respectively. Conclusions: The contribution of the microstructure and mechanical properties of the C2–C7 cervical spine to the movement of the cervical spine is different and has a good correlation and the effectiveness of the finite element model is also verified that we can correctly calculate the microstructure and mechanical properties of the cervical articular process to evaluate the stability and injury risk of cervical vertebrae by the established model.

Q-Dixon and GRAPPATINI T2 Mapping Parameters: A Whole Spinal Assessment of the Relationship Between Osteoporosis and Intervertebral Disc Degeneration

BACKGROUND

The relationship between osteoporosis and intervertebral disc (IVD) degeneration remains controversial. Novel quantitative Dixon (Q-Dixon) and GRAPPATINI T2 mapping techniques have shown potential for evaluating the biochemical components of the spine.

PURPOSE

To investigate the correlation of osteoporosis with IVD degeneration in postmenopausal women.

STUDY TYPE

Prospective.

SUBJECTS

A total of 105 postmenopausal females (mean age, 65 years; mean body mass index, 26 kg/m² ).

FIELD STRENGTH/SEQUENCE

3 T; sagittal; 6-echo Q-Dixon, multiecho spin-echo GRAPPATINI T2 mapping, turbo spin echo (TSE) T1-weighted and TSE T2-weighted sequences.

ASSESSMENT

The subjects were divided into normal (N = 47), osteopenia (N = 28), and osteoporosis (N = 30) groups according to quantitative computed tomography examination. The Pfirrmann grade of each IVD was obtained. Region of interest analysis was performed separately by two radiologists (X.L., with 10 years of experience, and S.C., with 20 years of experience) on a fat fraction map and T2 map to calculate the bone marrow fat fraction (BMFF) from the L1 to L5 vertebrae and the T2 values of each adjacent IVD separately.

STATISTICAL TESTS

One-way analysis of variance, post-hoc comparisons, and Kruskal-Wallis H tests were performed to evaluate the differences in the magnetic resonance imaging parameters between the groups. The relationships between BMFF and the IVD features were analyzed using the Spearman correlation analysis and linear regression models.

RESULTS

There were significant differences in BMFF among the three groups. The osteoporosis group had higher BMFF values (64.5 ± 5.9%). No significant correlation was found between BMFF and Pfirrmann grade (r = 0.251, P = 0.06). BMFF was significantly negatively correlated with the T2 of the adjacent IVD from L1 to L3 (r = -0.731; r = -0.637; r = -0.547), while significant weak correlations were found at the L4 to L5 levels (r = -0.337; r = -0.278).

DATA CONCLUSION

This study demonstrated that osteoporosis is associated with IVD degeneration.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 4.

Lumbar Disk Degeneration in Female Patients with and without Ovariectomy: A Case-Control Study

OBJECTIVE

We sought to provide clinical evidence of the potential influence of ovariectomy (OVX) on intervertebral disk degeneration.

METHODS

We retrospectively reviewed patients with a history of OVX who visited our hospital for lower back pain. In addition, 60 age-matched patients without OVX were randomly selected as control subjects. Next, the following demographic data were recorded and compared among groups: age, body mass index, duration of OVX, history of smoking, alcohol use, hypertension, diabetes, cardiocerebrovascular disease, hyperlipemia, osteoporosis, and degenerative spondylolisthesis. Next, the severity of lumbar disk degeneration, evaluated by the modified Pfirrmann grading system, was compared between groups. Data analyses were performed with SPSS 20.0. software.

RESULTS

A total of 15 OVX (unilateral, n = 10; bilateral, n = 5) patients were included with a mean age of 62.40 ± 10.64. The average durations of OVX were 21.33 ± 9.24 years. There existed no remarkable intergroup differences in the demographic data (P > 0.05). Overall, the average Pfirrmann grading scores from L1/2 to L5/S1 presented as L1/2 < L2/3 < L3/4 ≤ L5/S1 ≤ L4/5, with no marked differences between groups (P > 0.05). Nevertheless, OVX groups displayed a relatively higher score at each level than non-OVX group. Moreover, the scores from L3/4 to L5/S1 were higher in the bilateral OVX group relative to the unilateral OVX group while they were equal at L1/2 and L2/3.

CONCLUSIONS

Our findings demonstrated that OVX contributed to the progression of lumbar disk degeneration to some extent, but it appeared to be a long-term event.

3D assessment of intervertebral disc degeneration in zebrafish identifies changes in bone density that prime disc disease

Back pain is a common condition with a high social impact and represents a global health burden. Intervertebral disc disease (IVDD) is one of the major causes of back pain; no therapeutics are currently available to reverse this disease. The impact of bone mineral density (BMD) on IVDD has been controversial, with some studies suggesting osteoporosis as causative for IVDD and others suggesting it as protective for IVDD. Functional studies to evaluate the influence of genetic components of BMD in IVDD could highlight opportunities for drug development and repurposing. By taking a holistic 3D approach, we established an aging zebrafish model for spontaneous IVDD. Increased BMD in aging, detected by automated computational analysis, is caused by bone deformities at the endplates. However, aged zebrafish spines showed changes in bone morphology, microstructure, mineral heterogeneity, and increased fragility that resembled osteoporosis. Elements of the discs recapitulated IVDD symptoms found in humans: the intervertebral ligament (equivalent to the annulus fibrosus) showed disorganized collagen fibers and herniation, while the disc center (nucleus pulposus equivalent) showed dehydration and cellular abnormalities. We manipulated BMD in young zebrafish by mutating sp7 and cathepsin K, leading to low and high BMD, respectively. Remarkably, we detected IVDD in both groups, demonstrating that low BMD does not protect against IVDD, and we found a strong correlation between high BMD and IVDD. Deep learning was applied to high-resolution synchrotron µCT image data to analyze osteocyte 3D lacunar distribution and morphology, revealing a role of sp7 in controlling the osteocyte lacunar 3D profile. Our findings suggest potential avenues through which bone quality can be targeted to identify beneficial therapeutics for IVDD.

Osteoporosis and Endplate Damage Correlation Using a Combined Approach of Hounsfield Unit Values and Total Endplate Scores: A Retrospective Cross-Sectional Study

Purpose

Osteoporosis and endplate damage, two primary orthopedic disorders that have adverse effects on the quality of life of older adults, may have some previously unknown relationship. The purpose of this study was to determine the potential association between osteoporosis and endplate damage with two specific imaging scoring systems and analyze the underlying mechanisms.

Patients and Methods

A cross-sectional study including 156 patients with degenerative disc disease (DDD) who visited our department in 2018 was performed. Data including age, sex, body mass index, Hounsfield unit (HU) values utilizing computed tomography (CT), and total endplate scores (TEPSs) using magnetic resonance imaging (MRI) of all patients were retrospectively collected and analyzed. The average HU value and TEPS of L1–L4 were used to represent the degrees of bone mineral density (BMD) and endplate damage, respectively. Patients with an HU value < 110 were defined as having osteoporosis and placed in the low-BMD group; otherwise, they were placed in the normal-BMD group. Multivariate logistic regression models were used to determine the independent factors of endplate damage.

Results

The TEPSs in the low-BMD group were significantly higher (6.4 ± 1.6 vs 5.0 ± 0.9, p < 0.001) overall and in every segment of L1–L4 (p < 0.01). A significant negative correlation was found between TEPS and HU values (p < 0.001). The HU value (odds ratio [OR] 0.221; 95% confidence interval [CI], 0.148–0.295, p < 0.001), age (OR 0.047; 95% CI, 0.029–0.224, p < 0.001), and BMD (OR 3.796; 95% CI, 2.11–7.382, p < 0.05) were independent factors influencing endplate damage.

Conclusion

A significantly positive correlation was observed between osteoporosis and endplate damage, indicating the requirement for a more comprehensive therapeutic regimen for treating patients with DDD complicated with osteoporosis.

The Fungal Metabolite (+)-Terrein Abrogates Ovariectomy-Induced Bone Loss and Receptor Activator of Nuclear Factor-κB Ligand-Induced Osteoclastogenesis by Suppressing Protein Kinase-C α/βII Phosphorylation

Osteoporosis is a common disease characterized by a systemic impairment of bone mass and microarchitecture that results in fragility fractures. Severe bone loss due to osteoporosis triggers pathological fractures and consequently decreases the daily life activity and quality of life. Therefore, prevention of osteoporosis has become an important issue to be addressed. We have reported that the fungal secondary metabolite (+)-terrein (TER), a natural compound derived from Aspergillus terreus, has shown receptor activator of nuclear factor-κB ligand (RANKL)–induced osteoclast differentiation by suppressing nuclear factor of activated T-cell 1 (NFATc1) expression, a master regulator of osteoclastogenesis. TER has been shown to possess extensive biological and pharmacological benefits; however, its effects on bone metabolism remain unclear. In this study, we investigated the effects of TER on the femoral bone metabolism using a mouse-ovariectomized osteoporosis model (OVX mice) and then on RANKL signal transduction using mouse bone marrow macrophages (mBMMs). In vivo administration of TER significantly improved bone density, bone mass, and trabecular number in OVX mice (p < 0.01). In addition, TER suppressed TRAP and cathepsin-K expression in the tissue sections of OVX mice (p < 0.01). In an in vitro study, TER suppressed RANKL-induced phosphorylation of PKCα/βII, which is involved in the expression of NFATc1 (p < 0.05). The PKC inhibitor, GF109203X, also inhibited RANKL-induced osteoclastogenesis in mBMMs as well as TER. In addition, TER suppressed the expression of osteoclastogenesis-related genes, such as Ocstamp, Dcstamp, Calcr, Atp6v0d2, Oscar, and Itgb3 (p < 0.01). These results provide promising evidence for the potential therapeutic application of TER as a novel treatment compound against osteoporosis.

Investigating the role of culture conditions on hypertrophic differentiation in human cartilage endplate cells

Cartilage endplate degeneration/calcification has been linked to the onset and progression of intervertebral disc degeneration and there is a critical need to understand mechanisms, such as hypertrophic differentiation, of cartilage endplate degeneration/calcification to inform treatment strategies for discogenic back pain. In vitro cell culture conditions capable of inducing hypertrophic differentiation are used to study pathophysiological mechanisms in articular chondrocytes, but culture conditions capable of inducing a hypertrophic cartilage endplate cell phenotype have yet to be explored. The goal of this study was to investigate the role of culture conditions capable of inducing hypertrophic differentiation in articular chondrocytes on hypertrophic differentiation in human cartilage endplate cells. Isolated human cartilage endplate cells were cultured as pellets for 21 days at either 5% O₂ (physiologic for cartilage) or 20.7% O₂ (hyperoxic) and treated with 10% fetal bovine serum or Wnt agonist, two stimuli used to induce hypertrophic differentiation in articular chondrocytes. Cartilage endplate cells did not exhibit a hypertrophic cell morphology in response to fetal bovine serum or Wnt agonist but did display other hallmarks of chondrocyte hypertrophy and degeneration such as hypertrophic gene and protein expression, and a decrease in healthy proteoglycans and an increase in fibrous collagen accumulation. These findings demonstrate that cartilage endplate cells take on a degenerative phenotype in response to hypertrophic stimuli in vitro, but do not undergo classical changes in morphology associated with hypertrophic differentiation regardless of oxygen levels, highlighting potential differences in the response of cartilage endplate cells versus articular chondrocytes to the same stimuli.

Denosumab alleviates intervertebral disc degeneration adjacent to lumbar fusion by inhibiting endplate osteochondral remodeling and vertebral osteoporosis in ovariectomized rats

Background

Although adjacent segmental intervertebral disc degeneration (ASDD) is one of the most common complications after lumbar fusion, its exact mechanism remains unclear. As an antibody to RANKL, denosumab (Dmab) effectively reduces bone resorption and stimulates bone formation, which can increase bone mineral density (BMD) and improve osteoporosis. However, it has not been confirmed whether Dmab has a reversing or retarding effect on ASDD.

Methods

Three-month-old female Sprague-Dawley rats that underwent L4–L5 posterolateral lumbar fusion (PLF) with spinous-process wire fixation 4 weeks after bilateral ovariectomy (OVX) surgery were given Dmab 4 weeks after PLF surgery (OVX+PLF+Dmab group). In addition, the following control groups were defined: Sham, OVX, PLF, and OVX+PLF (n=12 each). Next, manual palpation and X-ray were used to evaluate the state of lumbar fusion. The bone microstructure in the lumbar vertebra and endplate as well as the disc height index (DHI) of L5/6 was evaluated by microcomputed tomography (μCT). The characteristic alterations of ASDD were identified via Safranin-O green staining. Osteoclasts were detected using tartrate-resistant acid phosphatase (TRAP) staining, and the biomechanical properties of vertebrae were evaluated. Aggrecan (Agg), metalloproteinase-13 (MMP-13), and a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4) expression in the intervertebral disc were detected by immunohistochemistry and real-time polymerase chain reaction (RT-PCR) analysis. In addition, the expression of CD24 and Sox-9 was assessed by immunohistochemistry.

Results

Manual palpation showed clear evidence of the fused segment’s immobility. Compared to the OVX+PLF group, more new bone formation was observed by X-ray examination in the OVX+PLF+Dmab group. Dmab significantly alleviated ASDD by retaining disc height index (DHI), decreasing endplate porosity, and increasing vertebral biomechanical properties and BMD. TRAP staining results showed a significantly decreased number of active osteoclasts after Dmab treatment, especially in subchondral bone and cartilaginous endplates. Moreover, the protein and mRNA expression results in discs (IVDs) showed that Dmab not only inhibited matrix degradation by decreasing MMP-13 and ADAMTS-4 but also promoted matrix synthesis by increasing Agg. Dmab maintained the number of notochord cells by increasing CD24 but reducing Sox-9.

Conclusions

These results suggest that Dmab may be a novel therapeutic target for ASDD treatment.

Intervertebral Disc Degeneration Induced by Needle Puncture and Ovariectomy: A Rat Coccygeal Model

Objectives

To establish a novel animal model of intervertebral disc degeneration (IVDD) in rats and to investigate the effect of 17β-estradiol (E2) intervention in this model.

Methods

This study was divided into two parts: animal model (four groups: Sham, ovariectomy (OVX), Puncture, and OVX+Puncture; three-time points: 4, 8, and 12 weeks; three female rats/group/time point) and drug intervention (Sham, OVX+Puncture+corn oil, and OVX+Puncture+E2; three female rats/group). The rats were analyzed by micromagnetic resonance imaging (MRI), hematoxylin and eosin (HE) staining, and safranin-O staining.

Results

MRI and histological scores significantly differed among the four groups at the three-time points (all P < 0.05). IVDD progressed with time in the OVX, Puncture, and OVX+Puncture groups (all P < 0.05). The changes were the most obvious in the OVX+Puncture group. In the E2 intervention part, the Veh group had the worst MRI signals and histological scores (P < 0.05). The MRI scores in the E2 group were less obvious compared to the Sham group (P > 0.05). Also, the histological scores were significantly different between the Sham and E2 groups (P < 0.05).

Conclusions

The combination of ovariectomy and needle puncture can synergically induce IVDD in rat coccygeal discs. Estrogen treatment can effectively ameliorate IVDD progression in the newly established IVDD models.

Intervertebral disc degeneration and regeneration: a motion segment perspective

Back and neck pain have become primary reasons for disability and healthcare spending globally. While the causes of back pain are multifactorial, intervertebral disc degeneration is frequently cited as a primary source of pain. The annulus fibrosus (AF) and nucleus pulposus (NP) subcomponents of the disc are common targets for regenerative therapeutics. However, disc degeneration is also associated with degenerative changes to adjacent spinal tissues, and successful regenerative therapies will likely need to consider and address the pathology of adjacent spinal structures beyond solely the disc subcomponents. This review summarises the current state of knowledge in the field regarding associations between back pain, disc degeneration, and degeneration of the cartilaginous and bony endplates, the AF-vertebral body interface, the facet joints and spinal muscles, in addition to a discussion of regenerative strategies for treating pain and degeneration from a whole motion segment perspective.

Comprehensive evaluation of differential long non-coding RNA and gene expression in patients with cartilaginous endplate degeneration of cervical vertebra

Long non-coding RNAs (lncRNAs) are emerging as key regulators in gene expression; however, little is currently known regarding their role in cartilaginous endplate (CE) degeneration (CED) of cervical vertebra. The present study aimed to investigate the expression levels of lncRNAs and analyze their potential functions in CED of cervical vertebra in patients with cervical fracture and cervical spondylosis. Human competitive endogenous RNA (ceRNA) array was used to analyze lncRNA and mRNA expression levels in CE samples from patients with cervical fracture and cervical spondylosis, who received anterior cervical discectomy and fusion. Differentially expressed lncRNAs (DELs) or differentially expressed genes (DEGs) were identified and functionally analyzed, using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. An lncRNA-microRNA(miRNA)-mRNA ceRNA regulatory network was constructed based on the DELs and DEGs, and the ceRNA network was visualized using Cytoscape 3.7.2 software. In total, one downregulated mRNA, one upregulated miRNA and five downstream regulated lncRNAs were identified using reverse transcription-quantitative PCR in CED and healthy CE samples. A total of 369 lncRNAs and 246 mRNAs were identified as differentially expressed in CE. The GO and KEGG analyses demonstrated that the majority of GO and KEGG enrichments were associated with CED. Furthermore, a ceRNA network was established, including 168 putative miRNA response elements, 189 upregulated and 37 downregulated lncRNAs and 47 upregulated and 10dow regulated DEGs. The present study analyzed the function of DEGs in the ceRNA network and filtered out the same items as in DEG-function enrichment analysis. These results provide a new perspective for an improved understanding of ceRNA-mediated gene regulation in cervical spondylosis, and provide a novel theoretical basis for further studies on the function of lncRNA in cervical spondylosis. However, further experiments are required to validate the results of the present study.

OPN Deficiency Increases the Severity of Osteoarthritis Associated with Aberrant Chondrocyte Senescence and Apoptosis and Upregulates the Expression of Osteoarthritis-Associated Genes

Objectives

A recent work has reported that the elevated osteopontin (OPN) levels in the articular cartilage and synovial fluid are correlated with the progressive osteoarthritis (OA) joint damage, and OPN has a protective effect against OA by suppressing the expressions of OA-associated genes. The present study examined whether the OPN deficiency was susceptible to OA through the regulation of chondrocyte senescence and apoptosis and the expressions of OA-associated genes.

Methods

The mRNA levels of COL2A1 and OPN were compared between human OA chondrocytes and normal chondrocytes. The effects of OPN siRNA on the SA-β-Gal expressions and the percentage of apoptotic chondrocytes were examined by using SA-β-Gal staining and apoptosis assay, and the effects on the expressions of COL2A1 and OA-associated genes (COL10A1, IL-1β, TNF-ɑ, MMP-13, and ADAMTS5) were examined by western blot analysis and quantitative real-time RT-PCR. Furthermore, an in vivo OA model was established to examine the effects of OPN siRNA on the senescence and apoptosis of OA chondrocytes and the expressions of OA-associated genes.

Results

The mRNA levels of COL2A1 and OPN were decreased in knee OA chondrocytes in comparison with those in normal chondrocytes. The OPN deficiency enhanced the senescence and apoptosis of OA chondrocytes and increased the expressions of COL10A1, IL-1β, TNF-ɑ, MMP-13, and ADAMTS5 but decreased the expression of COL2A1. Meanwhile, OPN deficiency could result in severe, accelerated OA in vivo, which was also associated with enhanced senescence and apoptosis of chondrocytes and elevated expressions of OA-associated genes.

Conclusions

The findings of this study suggest that the OPN deficiency can result in accelerated OA, which is associated with enhanced senescence and apoptosis of OA chondrocytes and the upregulated expressions of OA-associated genes.

Systematically characterized mechanism of treatment for lumbar disc herniation based on Yaobitong capsule ingredient analysis in rat plasma and its network pharmacology strategy by UPLC-MS/MS

ETHNOPHARMACOLOGICAL RELEVANCE

Yaobitong capsule (YBTC) was a traditional Chinese medicine (TCM) and it had clinically used to treat lumbar disc degeneration (LDH) for a long time. However, the active ingredients of YBTC absorption into the plasma and its pharmacological mechanism of treatment for LDH still remained unclear.

AIM OF THE STUDY

In this study, our research committed to identify the absorbed active ingredients of YBTC in rat plasma, and it may be a potential mechanism of action on LDH by the biological targets regulating related pathways.

MATERIALS AND METHODS

An ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established to identify the absorption components and metabolites of YBTC in rat plasma, and the network pharmacology was further investigated to illuminate its potential mechanism of treatment for LDH by the biological targets regulating related pathways.

RESULTS

The network analysis found that 56 components were identified as its main active ingredients including ginsenoside Rg1, ginsenoside Rb1, senkyunolide H, and tetrahydropalmatine, etc. Combining with biological process, cellular component and molecular functions of GO, and kyotoencyclopedia of genes and genomes pathway enrichment analysis to perform network topology analysis on core targets. These active ingredients regulated 29 mainly pathways by 87 direct target genes including MAPK, Ras, PI3K-Akt, and NF-kappa B signaling pathway, etc. CONCLUSION: In this study, the absorption active ingredients of YBTC in rat plasma were firstly combined with the network pharmacology investigation to elucidate its biological mechanism of treatment for LDH in vivo. It inhibited excessive inflammatory reactions, thereby reducing the sensitivity of the nerves to reduce pain and relieve LDH, and potential medicine targets could be identified to clarify the molecular mechanism of YBTCs' regulation of LDH.

Protocol for parallel proteomic and metabolomic analysis of mouse intervertebral disc tissues

The comprehensiveness of data collected by "omics" modalities has demonstrated the ability to drastically transform our understanding of the molecular mechanisms of chronic, complex diseases such as musculoskeletal pathologies, how biomarkers are identified, and how therapeutic targets are developed. Standardization of protocols will enable comparisons between findings reported by multiple research groups and move the application of these technologies forward. Herein, we describe a protocol for parallel proteomic and metabolomic analysis of mouse intervertebral disc (IVD) tissues, building from the combined expertise of our collaborative team. This protocol covers dissection of murine IVD tissues, sample isolation, and data analysis for both proteomics and metabolomics applications. The protocol presented below was optimized to maximize the utility of a mouse model for "omics" applications, accounting for the challenges associated with the small starting quantity of sample due to small tissue size as well as the extracellular matrix-rich nature of the tissue.

Anti-osteoporotic effects of Salvia miltiorrhiza Bunge EtOH extract both in ovariectomized and naturally menopausal mouse models

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia miltiorrhiza is a traditional oriental medicine widely used for preventing and treating disorders of the liver, menstrual, and blood circulation systems. Osteoporosis, loss of bone with age and/or estrogen deficiency, is an important causal factor of fracture. S. miltiorrhiza extract has been used to alleviate dysmenorrhea and painful osteoarthritis.

AIM OF THE STUDY

This study was performed to investigate the anti-osteoporosis activity of the Salvia miltiorrhiza ethanol extract (SME) in osteoporosis-prone conditions: ovariectomized (OVX) and naturally menopaused (NM) ICR mice.

MATERIALS AND METHODS

Anti-osteoporotic potentials of SME (50-200 mg/kg) were evaluated based on bone mineral density using microCT analysis, biochemical parameters, and changes in the gene expressions involved in bone resorption.

RESULTS

SME ameliorated the loss of trabecular bone both in OVX and NM mice. SME was effective in correcting aberrant levels of RANKL, osteocalcin, and BALP, which are critically involved in bone resorption. In addition, SME suppressed the expression of TRAF6 and NFATc1, which play a role in osteoclast differentiation.

CONCLUSIONS

SME suppressed the loss of trabecular bone via suppressing bone resorption and osteoclast differentiation both in OVX and NM mice. SME is likely to be developed as a therapeutic agent for osteoporosis.

Mechanics and Biology Interact in Intervertebral Disc Degeneration: A Novel Composite Mouse Model

The aim of this study was to distinguish the characteristics of intervertebral disc degeneration (IVDD) originating from mechanics imbalance, biology disruption, and their communion, and to develop a composite IVDD model by ovariectomy combined with lumbar facetectomy for mimicking elderly IVDD with osteoporosis and lumbar spinal instability. Mice were randomly divided into four groups and subjected to sham surgery (CON), ovariectomy (OVX), facetectomy (mechanical instability, INS) or their combination (COM), respectively. Radiographical (n = 4) and histological changes (n = 8) of L4/5 spinal segments were analyzed. Tartrate-resistant acid phosphatase (TRAP) staining was conducted to detect osteoclasts, and expression of osterix (OSX), type I collagen (Col I), type II collagen (Col II) and vascular endothelial growth factor (VEGF) were evaluated by immunochemistry. OVX affected the body's metabolism but INS did not, as the body weight increased and uterus weight decreased in OVX and COM mice compared to CON and INS mice. OVX, INS, and COM caused IVDD in various degrees at 12 weeks after surgery. However, the major pathogeneses of OVX- and INS-induced IVDD were different, which focused on endplate (EP) remodeling and annulus fibrosus (AF) collapse, respectively. OVX induced osteopenia of vertebra. In contrast, INS promoted the stress-adaptive increase of subchondral bone trabeculae. The COM produced a reproducible severe IVDD model with characteristics of sparse vertebral trabeculae, cartilaginous EP ossification, subchondral bone sclerosis, fibrous matrix disorder, angiogenesis, disc stiffness, as well as space fusion. Additionally, all groups had elevated bone and cartilage turnover compared with CON group, as the quantity of trap + osteoclasts and the osteogenic OSX expression increased in these groups. Likewise, the VEGF expression levels were similar, accompanied by the altered matrix expression of disc, including the changed distribution and contents of Col II and Col I. The findings suggested that the composite mouse model to some extent could effectively mimic the interactions of biology and mechanics engaged in the onset and natural course of IVDD, which would be more compatible with the IVDD of elderly with vertebral osteoporosis and spinal instability and benefit to further clarify the complicated mechanobiological environment of elderly IVDD progression.

Impact of pelvic incidence on lumbar osteophyte formation and disc degeneration in middle-aged and elderly people in a prospective cross-sectional cohort

PURPOSE

Pelvic incidence (PI) is unique to each individual and does not change throughout life. High PI is related to lumbar spondylolisthesis, but associations of PI with lumbar osteophyte formation and disc degeneration are unclear. The objective was to evaluate relationships of PI with lumbar osteophyte formation and disc degeneration, as well as spinal sagittal alignment and geriatric diseases, in middle-aged and elderly people.

METHODS

A total of 1002 volunteers (male: 434, female: 568, average age: 63.5) were prospectively examined for lumbar osteophyte formation (Nathan class ≥ 2) and disc degeneration (disc score ≥ 3). High (PI > 51, n = 501) and low (PI ≤ 51, n = 501) PI groups were defined. Clinical factors, frailty, sarcopenia, and physical quality of life (QOL) were compared between these groups, and risk factors for lumbar osteophyte formation and disc degeneration were identified in multivariate logistic regression analysis.

RESULTS

Physical QOL was poorer in people with lumbar osteophyte formation (54.8%) and disc degeneration (33.6%). Age, male gender, spinal parameters including PI, bone mineral density, back muscle strength, and gait ability differed significantly between the groups, whereas frailty and sarcopenia were not significantly different. Low PI, low lumbar lordosis, elder age, male gender, high BMI, and weak back muscle strength were significant risk factors for lumbar osteophyte formation and disc degeneration.

CONCLUSIONS

Low PI was identified as a risk factor for lumbar osteophyte formation and disc degeneration, both of which reduce physical QOL in middle-aged and elderly people. These slides can be retrieved under Electronic Supplementary Material.

NIPA2 regulates osteoblast function by modulating mitophagy in type 2 diabetes osteoporosis

The highly selective magnesium transporter non-imprinted in Prader-Willi/Angelman syndrome region protein 2 (NIPA2) has recently been associated with the development and progression of type 2 diabetes osteoporosis, but the mechanisms involved are still poorly understood. Because mitophagy is involved in the pathology of type 2 diabetes osteoporosis, the present study aimed to explore the relationship among NIPA2, mitophagy and osteoblast osteogenic capacity. NIPA2 expression was reduced in C57BKS background db/db mice and in vitro models of type 2 diabetes osteoporosis, and the activation of mitophagy in primary culture osteoblast-derived from db/db mice and in high glucose-treated human fetal osteoblastic cells (hFOB1.19) was observed. Knockdown, overexpression of NIPA2 and pharmacological inhibition of peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) showed that NIPA2 increased osteoblast function, which was likely regulated by PTEN induced kinase 1 (PINK1)/E3 ubiquitin ligase PARK2 (Parkin)-mediated mitophagy via the PGC-1α/forkhead box O3a(FoxO3a)/mitochondrial membrane potential (MMP) pathway. Furthermore, the negative effect of mitophagy on osteoblast function was confirmed by pharmacological regulation of mitophagy and knockdown of Parkin. Taken together, these results suggest that NIPA2 positively regulates the osteogenic capacity of osteoblasts via the mitophagy pathway in type 2 diabetes.

Coenzyme Q10 Regulation of Apoptosis and Oxidative Stress in H2O2 Induced BMSC Death by Modulating the Nrf-2/NQO-1 Signaling Pathway and Its Application in a Model of Spinal Cord Injury

Spinal cord injury (SCI) has always been considered to be a devastating problem that results in catastrophic dysfunction, high disability rate, low mortality rate, and huge cost for the patient. Stem cell-based therapy, especially using bone marrow mesenchymal stem cells (BMSCs), is a promising strategy for the treatment of SCI. However, SCI results in low rates of cell survival and a poor microenvironment, which limits the therapeutic efficiency of BMSC transplantation. Coenzyme Q10 (CoQ10) is known as a powerful antioxidant, which inhibits lipid peroxidation and scavenges free radicals, and its combined effect with BMSC transplantation has been shown to have a powerful impact on protecting the vitality of cells, as well as antioxidant and antiapoptotic compounds in SCI. Therefore, we aimed to evaluate whether CoQ10 could decrease oxidative stress against the apoptosis of BMSCs in vitro and explored its molecular mechanisms. Furthermore, we investigated the protective effect of CoQ10 combined with BMSCs transplanted into a SCI model to verify its ability. Our results demonstrate that CoQ10 treatment significantly decreases the expression of the proapoptotic proteins Bax and Caspase-3, as shown through TUNEL-positive staining and the products of oxidative stress (ROS), while increasing the expression of the antiapoptotic protein Bcl-2 and the products of antioxidation, such as glutathione (GSH), against apoptosis and oxidative stress, in a H2O2-induced model. We also identified consistent results from the CoQ10 treatment of BMSCs transplanted into SCI rats in vivo. Moreover, the Nrf-2 signaling pathway was also investigated in order to detail its molecular mechanism, and the results show that it plays an important role, both in vitro and in vivo. Thus, CoQ10 exerts an antiapoptotic and antioxidant effect, as well as improves the microenvironment in vitro and in vivo. It may also protect BMSCs from oxidative stress and enhance their therapeutic efficiency when transplanted for SCI treatment.

Coenzyme Q10 suppresses oxidative stress and apoptosis via activating the Nrf-2/NQO-1 and NF-κB signaling pathway after spinal cord injury in rats

Spinal cord injury (SCI) is one of the most devastating diseases that may cause paralysis, disability and irreversible loss of functions, which ultimately lead to permanent disabilities and a decrease in patient life expectancy. Coenzyme Q10 (CoQ10) is a lipid-soluble vitamin-like benzoquinone compound that can exert antioxidant and anti-apoptotic functions in a variety of diseases. However, the antioxidant and anti-apoptotic effects of CoQ10 in the treatment of SCI are still unknown. Therefore, we designed experiments to measure the changes in antioxidant capacity (glutathione (GSH), superoxide dismutase (SOD) and the end product of lipid peroxidation (MDA)) and apoptosis products (Bax, Bcl-2 and Caspase-3) to evaluate the protective effects of CoQ10 on SCI and investigated whether CoQ10 exerts its functions through the Nrf-2/NQO-1 and NF-κB signaling pathway. Our results showed that CoQ10 treatment could significantly decrease the levels of oxidative products (MDA) and increase the activities of antioxidant enzymes (SOD and GSH) against oxidative stress, as well as decrease the levels of pro-apoptotic proteins (Bax and Caspase-3) and increase the levels of anti-apoptotic proteins (Bcl-2) against apoptosis after SCI. We also observed that CoQ10 exerted beneficial effects through the Nrf-2/NQO-1 and NF-κB signaling pathway. These findings suggested that CoQ10 had a protective effect by decreasing oxidative stress and apoptosis after SCI. Thus, our data may provide a new approach wherein CoQ10 may be considered as a potential effective therapeutic for the treatment of SCI.

Osteoporosis therapies might lead to intervertebral disc degeneration via affecting cartilage endplate

Osteoporosis and intervertebral disc degeneration (IDD) are both age-related diseases of the musculoskeletal system. With the average life expectancy longer than ever, the morbidity caused by these two diseases is increasing. Nowadays, treatment strategies for osteoporosis are mainly aimed at increasing the mineral density of the bone. Some of these therapies, including vitamin D, calcium, bisphosphonates, Wnt signal activators and parathyroid hormone regulators, have been suggested to be capable of causing calcification of the cartilage endplate in the intervertebral disc. This alteration could block nutrient and oxygen transportation to the center part of the disc, thus lead to intervertebral disc degeneration. Consequently, we hypothesize that osteoporosis therapies might be a potential risk for IDD. This assumption indicates that we should take the alterations of the cartilage endplate into consideration in further osteoporosis treatment to avoid IDD in the patient.