Primary prevention of disc degeneration-related symptoms

Apigenin Alleviates Intervertebral Disc Degeneration via Restoring Autophagy Flux in Nucleus Pulposus Cells

Oxidative stress–induced apoptosis and senescence of nucleus pulposus (NP) cells play a crucial role in the progression of intervertebral disc degeneration (IVDD). Accumulation of studies has shown that activated autophagy and enhanced autophagic flux can alleviate IVDD. In this study, we explored the effects of apigenin on IVDD in vitro and in vivo. Apigenin was found to inhibit tert-butyl hydroperoxide (TBHP)–induced apoptosis, senescence, and ECM degradation in NP cells. In addition, apigenin treatment can restore the autophagic flux blockage caused by TBHP. Mechanistically, we found that TBHP may induce autophagosome and lysosome fusion interruption and lysosomal dysfunction, while apigenin alleviates these phenomena by promoting the nuclear translocation of TFEB via the AMPK/mTOR signaling pathway. Furthermore, apigenin also exerts a protective effect against the progression of IVDD in the puncture-induced rat model. Taken together, these findings indicate that apigenin protects NP cells against TBHP-induced apoptosis, senescence, and ECM degradation via restoration of autophagic flux in vitro, and it also ameliorates IVDD progression in rats in vivo, demonstrating its potential for serving as an effective therapeutic agent for IVDD.

School-based interventions to improve spinal health of children and adolescents: a systematic review

Background: The prevalence of spinal pain is high in children and adolescents attending school. There are no evidence-based guidelines to promote spinal health (spinal pain and spinal well-being) in schoolsPurpose: This study aimed to 1) determine the usefulness of school-based interventions in promoting spinal health in children and adolescents and 2) synthesize the evidence in a user-friendly infographic.Methods: A search was performed across eight databases from the inception of the databases to August 2019 for full-text English-language articles which assessed the effect of school-based interventions on spinal health. Spinal health outcomes included pain limited to the spinal area including lower back, upper back, neck, and neck-shoulder pain, and impacts of spinal pain (e.g., absenteeism from school). Studies were appraised for methodological quality (PEDro scale and Johanna Briggs Institute checklist). The usefulness of interventions was based on meta-analyses; calculated effect size; the number of spinal health outcomes; and the direction of the (summary) effect of the intervention.Results: Twenty-two studies were included. Four interventions were identified: 1) exercise; 2) education; 3) the combination of exercise and education; and 4) furniture.Conclusion: School-based exercise is most useful to promote spinal health in the short term, followed by a combination of exercise and education, and education-only interventions.

Cardamonin protects nucleus pulposus cells against IL-1β-induced inflammation and catabolism via Nrf2/NF-κB axis

Intervertebral disc degeneration (IVDD) is one of the major causes of low back pain, but effective therapies are still lacking because of its complicated pathology. It has been demonstrated that increased levels of interleukin-1β (IL-1β) may promote the development of IVDD. Cardamonin (CAR) is a chalcone extracted from Alpinia katsumadai and other plants. It exhibits an anti-inflammatory effect in multiple diseases. In the present study, we investigated the protective effects of CAR on rat nucleus pulposus (NP) cells under IL-1β stimulation in vitro and in a puncture-induced rat IVDD model in vivo. We explored the CAR treatment's inhibition of the expression of inflammatory factors such as cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), prostaglandin E2 (PGE2), nitric oxide (NO), tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in rat NP cells. Moreover, the up-regulation of matrix metalloproteinase-13 (MMP-13) and thrombospondin motifs 5 (ADAMTS-5) and the degradation of aggrecan and collagen II induced by IL-1β were reversed by CAR. Mechanistically, we demonstrated that CAR inhibited nuclear factor kappa B (NF-κB) signaling by activating the nuclear factor erythroid-derived 2-like 2 (Nrf2) in IL-1β-induced rat NP cells. Furthermore, the protective effect of CAR was shown in the IVDD model through persistent intragastric administration. Taken together, our results revealed that CAR could activate the Nrf2/HO-1 signaling axis and be a novel agent for IVDD therapy.

Ferroportin-Dependent Iron Homeostasis Protects against Oxidative Stress-Induced Nucleus Pulposus Cell Ferroptosis and Ameliorates Intervertebral Disc Degeneration In Vivo

Ferroptosis is a specialized form of regulated cell death that is charactered by iron-dependent lethal lipid peroxidation, a process associated with multiple diseases. However, its role in the pathogenesis of intervertebral disc degeneration (IVDD) is rarely investigated. This study is aimed at investigating the role of ferroptosis in oxidative stress- (OS-) induced nucleus pulposus cell (NPC) decline and the pathogenesis of IVDD and determine the underlying regulatory mechanisms. We used tert-butyl hydroperoxide (TBHP) to simulate OS conditions around human NPCs. Flow cytometry and transmission electron microscopy were used to identify ferroptosis, while iron assay kit, Perl's staining, and western blotting were performed to assay the intracellular iron levels. A ferroportin- (FPN-) lentivirus and FPN-siRNA were constructed and used to explore the relationship between FPN, intracellular iron homeostasis, and ferroptosis. Furthermore, hinokitiol, a bioactive compound known to specifically resist OS and restore FPN function, was evaluated for its therapeutic role in IVDD both in vitro and in vivo. The results indicated that intercellular iron overload plays an essential role in TBHP-induced ferroptosis of human NPCs. Mechanistically, FPN dysregulation is responsible for intercellular iron overload under OS. The increase in nuclear translocation of metal-regulatory transcription factor 1 (MTF1) restored the function of FPN, abolished the intercellular iron overload, and protected cells against ferroptosis. Additionally, hinokitiol enhanced the nuclear translocation of MTF1 by suppressing the JNK pathway and ameliorated the progression of IVDD in vivo. Taken together, our results demonstrate that ferroptosis and FPN dysfunction are involved in the NPC depletion and the pathogenesis of IVDD under OS. To the best of our knowledge, this is the first study to demonstrate the protective role of FPN in ferroptosis of NPCs, suggesting its potential used as a novel therapeutic target against IVDD.

Back pain in elementary schoolchildren is related to screen habits

PURPOSE

Verify the influences of physical activity level, nutritional status and screen habits on the prevalence of back pain in Brazilian students.

METHODS

The sample consisted of 577 schoolchildren (female = 274; male = 303) aged between 10 and 16 years old, regularly enrolled in the 6th grade of elementary school living in the metropolitan area of the Alto Tietê of the state of São Paulo, Brazil. The prevalence, intensity and frequency of pain was verified with the Back Pain Assessment Instrument. The usual practice of physical activity was verified with the Physical Activity Questionnaire for Older Children/Adolescent. Nutritional status was analyzed using Body Mass Index. Screen habits were obtained through a previously structured questionnaire.

RESULTS

The Chi-square test indicated that pain complaint and its prevalence in the cervical region are significantly higher in females (p < 0.05). The multiple logistic regression test revealed that watching television influences the prevalence of cervical pain and that the use of more than one screen increases the occurrence of low back pain in male students (p < 0.05).

CONCLUSION

Female students were the most affected by back pain complain, especially in the cervical region. However, factors associated with the prevalence of back pain were found only in males.

Restoration of Autophagic Flux Rescues Oxidative Damage and Mitochondrial Dysfunction to Protect against Intervertebral Disc Degeneration

Oxidative stress-induced mitochondrial dysfunction and nucleus pulposus (NP) cell apoptosis play crucial roles in the development of intervertebral disc degeneration (IDD). Increasing studies have shown that interventions targeting impaired autophagic flux can maintain cellular homeostasis by relieving oxidative damage. Here, we investigated the effect of curcumin (CUR), a known autophagy activator, on IDD in vitro and in vivo. CUR suppressed tert-butyl hydroperoxide- (TBHP-) induced oxidative stress and mitochondrial dysfunction and thereby inhibited human NP cell apoptosis, senescence, and ECM degradation. CUR treatment induced autophagy and enhanced autophagic flux in an AMPK/mTOR/ULK1-dependent manner. Notably, CUR alleviated TBHP-induced interruption of autophagosome-lysosome fusion and impairment of lysosomal function and thus contributed to the restoration of blocked autophagic clearance. These protective effects of CUR in TBHP-stimulated human NP cells resembled the effects produced by the autophagy inducer rapamycin, but the effects were partially eliminated by 3-methyladenine- and compound C-mediated inhibition of autophagy initiation or chloroquine-mediated obstruction of autophagic flux. Lastly, CUR also exerted a protective effect against puncture-induced IDD progression in vivo. Our results showed that suppression of excessive ROS production and mitochondrial dysfunction through enhancement of autophagy coupled with restoration of autophagic flux ameliorated TBHP-induced human NP cell apoptosis, senescence, and ECM degradation. Thus, maintenance of the proper functioning of autophagy represents a promising therapeutic strategy for IDD, and CUR might serve as an effective therapeutic agent for IDD.

Baseline musculoskeletal pain and impaired sleep related to school pressure influence the development of musculoskeletal pain in N = 107 adolescents in a 5-year longitudinal study

PURPOSE

This longitudinal study followed 10- to 13-year-old adolescents for 5 years to investigate the effects of juvenile musculoskeletal (MSK) pain and psychosocial risk factors on future pain. We further predicted that increased MSK pain at follow-up would be positively related to current school pressure at follow-up and negatively related to current sleep quality. Sleep quality was tested as a potential mediator of the link between school pressure and MSK pain at follow-up after controlling for baseline MSK pain.

METHODS

The baseline sample comprised 189 adolescents, and 5-year follow-up resulted in 107 15- to 18-year-old adolescents who had completed mandatory education. Adolescents responded to an online questionnaire about psychosocial stressors, MSK pain, school achievement and leisure activities. A longitudinal hierarchic linear regression including all significant baseline predictors was run to assess their impact on MSK pain 5 years later. Mediation analysis was used to investigate sleep quality as a potential mediator of the relationship between school pressure and MSK pain at follow-up.

RESULTS

Baseline MSK pain predicted MSK pain over a time lag of 5 years (ß = .26, p = .02). The relationship between follow-up school pressure and current MSK pain was mediated by sleep quality at follow-up (B = .17, SE_B = .07, 95% CI .06-.34) when baseline MSK pain was controlled.

CONCLUSIONS

Juvenile MSK pain predicts MSK pain in adolescence. A psychosocial mediation model including school pressure and sleep impairments has the potential to explain MSK pain mechanisms in adolescents. These slides can be retrieved under Electronic Supplementary Material.

Sirtuin 3-dependent mitochondrial redox homeostasis protects against AGEs-induced intervertebral disc degeneration

Intervertebral disc (IVD) degeneration contributes largely to pathoanatomical and degenerative changes of spinal structure that increase the risk of low back pain. Apoptosis in nucleus pulposus (NP) can aggravate IVD degeneration, and increasing studies have shown that interventions targeting NP cell apoptosis can ameliorate IVD degeneration, exhibiting their potential for use as therapeutic strategies. Recent data have shown that advanced glycation end products (AGEs) accumulate in NP tissues in parallel with the progression of IVD degeneration and form a microenvironment of oxidative stress. This study examined whether AGEs accumulation aggravates NP cell apoptosis and IVD degeneration, and explored the mechanisms underlying these effects. We observed that the viability and proliferation of human NP cells were significantly suppressed by AGEs treatment, mainly due to apoptosis. Furthermore, activation of the mitochondrial apoptosis pathway was detected after AGEs treatment. In addition, the molecular data showed that AGEs could significantly aggravate the generation of mitochondrial reactive oxygen species and prolonged activation of the mitochondrial permeability transition pore, as well as the increased level of Bax protein and decreased level of Bcl-2 protein in mitochondria. These effects could be reduced by antioxidant (2-(2,2,6,6-Tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl) triphenylphosphonium chloride (MitoTEMPO) and Visomitin (SKQ1). Importantly, we identified that impairment of Sirtuin3 (SIRT3) function and the mitochondrial antioxidant network were vital mechanisms in AGEs-induced oxidative stress and secondary human NP cell apoptosis. Finally, based on findings that nicotinamide mononucleotide (NMN) could restore SIRT3 function and rescue human NP cell apoptosis through adenosine monophosphate-activated protein kinase and peroxisome proliferator-activated receptor-γ coactivator 1α (AMPK-PGC-1α) pathway in vitro, we confirmed its protective effect on AGEs-induced IVD degeneration in vivo. In conclusion, our data demonstrate that SIRT3 protects against AGEs-induced human NP cell apoptosis and IVD degeneration. Targeting SIRT3 to improve mitochondrial redox homeostasis may represent a potential therapeutic strategy for attenuating AGEs-associated IVD degeneration.

Risk factors of non-specific spinal pain in childhood

PURPOSE

Non-specific spinal pain can occur at all ages and current evidence suggests that pediatric non-specific spinal pain is predictive for adult spinal conditions. A 5-year long, prospective cohort study was conducted to identify the lifestyle and environmental factors leading to non-specific spinal pain in childhood.

MATERIALS AND METHODS

Data were collected from school children aged 7-16 years, who were randomly selected from three different geographic regions in Hungary. The risk factors were measured with a newly developed patient-reported questionnaire (PRQ). The quality of the instrument was assessed by the reliability with the test-retest method. Test (N = 952) and validity (N = 897) datasets were randomly formed. Risk factors were identified with uni- and multivariate logistic regression models and the predictive performance of the final model was evaluated using the receiver operating characteristic (ROC) method.

RESULTS

The final model was built up by seven risk factors for spinal pain for days; age > 12 years, learning or watching TV for more than 2 h/day, uncomfortable school-desk, sleeping problems, general discomfort and positive familiar medical history (χ² = 101.07; df = 8; p < 0.001). The probabilistic performance was confirmed with ROC analysis on the test and validation cohorts (AUC = 0.76; 0.71). A simplified risk scoring system showed increasing possibility for non-specific spinal pain depending on the number of the identified risk factors (χ² = 65.0; df = 4; p < 0.001).

CONCLUSION

Seven significant risk factors of non-specific spinal pain in childhood were identified using the new, easy to use and reliable PRQ which makes it possible to stratify the children according to their individual risk. These slides can be retrieved under Electronic Supplementary Material.

Back pain prevalence and associated factors in children and adolescents: an epidemiological population study

OBJECTIVE

To identify the prevalence of back pain among Brazilian school children and the factors associated with this pain.

METHODS

All 1,720 schoolchildren from the fifth to the eight grade attending schools from the city of Teutonia, RS, Southern Brazil, were invited to participate in the study. From these, 1,597 children participated. We applied the Back Pain and Body Posture Evaluation Instrument. The dependent variable was back pain, while the independent one were demographic, socioeconomic, behavior and heredity data. The prevalence ratio was estimated by multivariate analysis using the Poisson regression model (α = 0.05).

RESULTS

The prevalence of back pain in the last three months was 55.7% (n = 802). The multivariate analysis showed that back pain is associated with the variables: sex, parents with back pain, weekly frequency of physical activity, daily time spent watching television, studying in bed, sitting posture to write and use the computer, and way of carrying the backpack.

CONCLUSIONS

The prevalence of back pain in schoolchildren is high and it is associated with demographic, behavior and heredity aspects.

Lumbar intervertebral discs T2 relaxometry and T1ρ relaxometry correlation with age in asymptomatic young adults

BACKGROUND

To investigate the detection of intervertebral disc (IVD) composition aging-related changes using T2 and T1ρ relaxometry in vivo in asymptomatic young adults.

METHODS

We recruited ninety asymptomatic and young adults (42 men and 48 women) between 20 and 40 years old. T2 and T1ρ lumbar spine mappings were acquired using 1.5 T magnetic resonance imaging (MRI) scanner. Two independent observers manually segmented 450 lumbar discs in all slices. They also performed sub region segmentation of annulus fibrosus (AF) and nucleus pulposus (NP) at the central MRI sagittal slices.

RESULTS

There was no difference between men and women for T2 (P=0.37) or T1ρ relaxometry (P=0.97). There was a negative correlation between age (20-40 years) and IVD T2 relaxation time of the whole disc (r=-0.30, P<0.0001), NP (r=-0.20 to -0.51, P<0.05) and posterior AF (r=-0.21 to -0.31, P<0.05) at all lumbar disc levels. There was no statistical correlation between aging and IVD T1ρ relaxation both for NP and AF.

CONCLUSIONS

T2 relaxometry detected gradual IVD dehydration in the first two decades of adulthood. We observed no significant variation of T1ρ or volumetry with aging in our study group. Our results suggest that T2 mapping may be more appropriate to detect early IVD aging changes.