Expression of Fas receptor and apoptosis in vertebral endplates with degenerative disc diseases categorized as Modic type I or II

From Modic to Disc Endplate Bone Marrow Complex - The Natural Course and Clinical Implication of Vertebral Endplate Changes

STUDY DESIGN

Review article.

OBJECTIVES

A review of literature on the epidemiology, natural course, pathobiology and clinical implications of vertebral endplate changes.

METHODS

A literature search was performed using the Cochrane Database of Systematic Reviews, EMBASE, and PubMed. Studies published over the last 10 years were analysed. The searches were performed using Medical Subject Headings terms, and the subheadings used were "Vertebral endplate changes", "Modic changes", "Disc Endplate Bone Marrow complex".

RESULTS

The disc, endplate (EP), and bone marrow region of the spine constitute a unified morphological and functional unit, with isolated degeneration of any one structure being uncommon. Disc degeneration causes endplate defects, which result in direct communication and a constant cross-talk between the disc and the vertebral body. This may result in a persistent inflammatory state of the vertebral bone marrow, serving as a major pain generator. This review article focuses on vertebral endplate changes and how the current understanding has progressed from the Modic classification to the Disc Endplate Bone Marrow complex classification. It provides a clear portrayal of the natural course of these alterations and their clinical implications in low back pain.

CONCLUSIONS

In light of the heightened interest and current prominence of vertebral endplate changes within the spine community, we must progress beyond the Modic changes to achieve a comprehensive understanding. The DEBM complex classification will play a major part in disc degeneration research and clinical care, representing a considerable advancement in our understanding of the vertebral endplate changes over the classical Modic changes.

The Relationship Between Inflammatory Processes and Apoptosis in Lumbar Disc Degeneration

OBJECTIVE

Degenerative Disc Disease (DDD) is a common health problem in the population. There are recent studies focusing on relationship between DDD and immunological factors. However, there is still a lack of data on the role of apoptosis in DDD pathophysiology. Therefore, we aimed to investigate the relationship between Modic-type changes and the apoptosis in DDD.

MATERIALS AND METHODS

Ninety adult male patients who presented with low back and/or radicular pain and were operated on due to lumbar disc herniation were included. Three groups were formed based on Modic type degeneration observed on magnetic resonance imaging. Specific parameters involved in the intrinsic and extrinsic pathways of apoptosis were assessed in excised disc materials using the enzyme-linked immunosorbent assay method.

RESULTS

All three groups formed according to Modic degeneration types were homogenous in all variances. Cytochrome-C was significantly decreased only in the Modic type-3 group, whereas Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Receptor-1, B-Cell Lymphoma-2 (Bcl-2) Homologous Antagonist Killer-1, Direct Inhibitor of Apoptosis-Binding Protein with Low Pi, and Bcl-2 Associated X Apoptosis Regulator levels were significantly different in both Modic type-2 and -3 groups. However, BH3 interacting domain death agonist and Bcl-2 levels were similar across all groups.

CONCLUSIONS

In conclusion, this study suggests that Direct Inhibitor of Apoptosis-Binding Protein with Low Pi, cytochrome - c, Bcl-2 Associated X Apoptosis Regulator, Bcl-2 Homologous Antagonist Killer-1, and Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Receptor-1proteins play important roles in the development and progression of DDD and are correlated with Modic types. Further studies are needed to explore the potential therapeutic role of inhibiting these apoptotic proteins in DDD.

Are Modic changes 'Primary infective endplatitis'?-insights from multimodal imaging of non-specific low back pain patients and development of a radiological 'Endplate infection probability score'

PURPOSE

To probe the pathophysiological basis of Modic change (MC) by multimodal imaging rather than by MRI alone.

METHODS

Nineteen radiological signs found in mild infections and traumatic endplate fractures were identified by MRI and CT, and by elimination, three signs unique to infection and trauma were distilled. By ranking the Z score, radiological 'Endplate Infection Probability Score' (EIPS) was developed. The score's ability to differentiate infection and traumatic endplate changes (EPC) was validated in a fresh set of 15 patients each, with documented infection and trauma. The EIPS, ESR, CRP, and Numeric Pain Rating Scale (NRS) were then compared between 115 patients with and 80 patients without MC.

RESULTS

The EIPS had a confidence of 66.4%, 83% and, 100% for scores of 4, 5 and, 6, respectively, for end plate changes suggesting infection. The mean EIPS was 4.85 ± 1.94 in patients with Modic changes compared to - 0.66 ± 0.49 in patients without Modic changes (p < 0.001). Seventy-eight (67.64%) patients with MC had a score of 6, indicating high infection possibility. There was a difference in the NRS (p < 0.01), ESR (p = 0.05), CRP (p < 0.01), and type of pain (p < 0.01) between patients with and without MC.

CONCLUSION

Multimodal imaging showed many radiological signs not easily seen in MRI alone and thus missed in Modic classification. There were distinct radiological differences between EPCs of trauma and infection which allowed the development of an EIPS. The scores showed that 67.64% of our study patients with Modic changes had EPCs resembling infection rather than trauma suggesting the possibility of an infective aetiology and allowing us to propose an alternate theory of 'Primary Endplatitis'.

Targeted therapy for intervertebral disc degeneration: inhibiting apoptosis is a promising treatment strategy

Intervertebral disc (IVD) degeneration (IDD) is a multifactorial pathological process associated with low back pain (LBP). The pathogenesis is complicated, and the main pathological changes are IVD cell apoptosis and extracellular matrix (ECM) degradation. Apoptotic cell loss leads to ECM degradation, which plays an essential role in IDD pathogenesis. Apoptosis regulation may be a potential attractive therapeutic strategy for IDD. Previous studies have shown that IVD cell apoptosis is mainly induced by the death receptor pathway, mitochondrial pathway, and endoplasmic reticulum stress (ERS) pathway. This article mainly summarizes the factors that induce IDD and apoptosis, the relationship between the three apoptotic pathways and IDD, and potential therapeutic strategies. Preliminary animal and cell experiments show that targeting apoptotic pathway genes or drug inhibition can effectively inhibit IVD cell apoptosis and slow IDD progression. Targeted apoptotic pathway inhibition may be an effective strategy to alleviate IDD at the gene level. This manuscript provides new insights and ideas for IDD therapy.

Reciprocal relationship between multifidus and psoas at L4-L5 level in women with low back pain

Background Low back pain (LBP) may originate from different sources such as intervertebral disc degeneration (IVDD), end-plate and paraspinal muscle changes. Our aim is to explore the relevance of paraspinal muscles' fat-infiltration in women with LBP and its association with IVDD and Modic changes.Methods Consecutive female patients presenting with chronic LBP to the outpatient clinics were included. Patients were evaluated in terms of IVDD, vertebral end-plate changes, and fatty infiltration in the paraspinal muscles at all lumbar levels on lumbar spine magnetic resonance imaging (MRI). Visual Analogue Scale (VAS) scores were recorded using our prospectively collected database.Results Patients with higher VAS scores were significantly more likely to have more fatty infiltration in the multifidus and less fatty infiltration in the psoas at L4-L5 level when compared to those with lower VAS scores (69.1 vs. 31.8%, p = 0.003). To predict LBP, fatty infiltration in the multifidus and psoas had odds ratio (OR) of 4 (p = 0.010), and 0.3 (p = 0.013), respectively; whereas disc degeneration had an OR of 0.5 (p = 0.028).Conclusion This is the first clinical cross-sectional study suggested that women with chronic low back pain could have less fat-infiltrated psoas to compensate more fat-infiltrated multifidus at L4-L5 disc level.

Lumbar Vertebral Endplate Defects on Magnetic Resonance Imaging in Degenerative Spondylolisthesis: Novel Classification, Characteristics, and Correlative Factor Analysis

BACKGROUND

Endplate defects are commonly seen in patients with lumbar degenerative disease. However, little is known about the presence of endplate defects in patients with degenerative spondylolisthesis (DS). In the present study, we have introduced a classification system for endplate defects in patients with DS using routine magnetic resonance imaging findings and explored the correlative factors.

METHODS

Endplate defects were classified into 3 major categories (rim defects, focal defects, and erosive defects) and 5 subtypes (anterior type, posterior type, arc type at the anterior rim, notch type, and Schmorl's nodes). The incidence rates of the endplate defects were compared between the slippage and nonslippage levels. The correlations between the endplate defects and age, sex, disc degeneration, Modic changes (MCs), body mass index, slippage segment, and slippage degree were analyzed.

RESULTS

Endplate defects were present in 47.43% of the endplates in DS. The most common endplate defects were rim defects. The occurrence of endplate defects, especially anterior defects, was more common at the slippage levels. Endplate defects were associated with age and closely related to MCs and the severity of disc degeneration. The slippage degree, slippage segment, body mass index, and sex differences were not associated with endplate defects in our study. The results obtained using this novel classification system were stable and consistent.

CONCLUSIONS

The results from the present study have shown that the novel radiological classification system of endplate defects is reliable. Endplate defects were associated with slippage but not with the slippage degree or slippage segment differences in DS. The correlation between endplate defects and age and between MCs and disc degeneration were important features on the magnetic resonance imaging scans of patients with DS.

Modic changes - An evidence-based, narrative review on its patho-physiology, clinical significance and role in chronic low back pain

OBJECTIVE

Lumbar degenerative spinal ailments are the most important causes for chronic low back pain. Modic changes (MC) are vertebral bone marrow signal intensity changes seen on MRI, commonly in association with degenerative disc disease (DDD). Despite being widely studied, majority of issues concerning MC are still controversial. The current narrative, evidence-based review comprehensively discusses the various aspects related to MC.

LITERATURE SEARCH

An elaborate search was made using keywords "Modic changes", "lumbar Modic changes", "Modic changes in lumbar spine", and "vertebral Endplate Spinal Changes", on pubmed and google (scholar.google.com) databases on the 3rd of March 2020. We identified crucial questions regarding Modic changes and included relevant articles pertaining to these topics for this narrative review.

RESULTS

The initial search using the keywords "Modic changes", "lumbar Modic changes", "Modic changes in lumbar spine", and "vertebral Endplate Spinal Changes" on pubmed yielded a total of 568, 412, 394 and 216 articles on "pubmed" database, respectively. A similar search using the aforementioned keywords yielded a total of 3650, 3548, 3726 and 21570 articles on "google scholar" database. The initial screening involved exclusion of duplicate articles, articles unrelated to MC, animal or other non-clinical studies, and articles in non-English literature based on abstracts or the titles of articles. This initial screening resulted in the identification of 405 articles. Full manuscripts were obtained for all these selected articles and thoroughly scrutinised at the second stage of article selection. All articles not concerning Modic changes, not pertaining to concerned questions, articles concerning other degenerative phenomena, articles discussing cervical or thoracic MC, case reports or animal studies, articles in non-English language and duplicate articles were excluded. Review articles, randomised controlled trials and level 1 studies were given preference. Overall, 69 articles were included in this review.

CONCLUSION

Modic change (MC) is a dynamic phenomenon and its true etiology is still not definitely known. Disc/end plate injury, occult discitis and autoimmune reactions seem to trigger an inflammatory cascade, which leads to their development. Male sex, older age, diabetes mellitus, genetic factors, smoking, obesity, spinal deformities, higher occupational loads and DDD are known risk factors. There is no conclusive evidence on the causative role of MC in chronic low back pain (LBP) or any influence on the long term outcome in patients with LBP or lumbar disc herniations (LDH). Patients with MC have been reported to have less satisfactory outcome following conservative treatment or discectomy, although the evidence is still unclear.

Detection of apoptosis and matrical degeneration within the intervertebral discs of rats due to passive cigarette smoking

Although low-back pain is considered to be associated with cigarette smoking, the influence of cigarette smoking on the intervertebral discs (IVD) has not been confirmed. We established a rat model of passive cigarette smoking-induced IVD degeneration, and investigated the cytohistological changes in the IVD and the accompanying changes in gene expression. IVD from rats exposed to 8 weeks of passive cigarette smoking were stained with Elastica van Gieson, and exhibited marked destruction of the supportive structure of the reticular matrix in the nucleus pulposus (NP). Positive signals on safranin O, alcian blue, type II collagen and aggrecan staining were decreased in the destroyed structure. Safranin O and type II collagen signals were also decreased in the cartilage end-plate (CEP) after 4- and 8-weeks of cigarette smoking. In the CEP, the potential for apoptosis was increased significantly, as demonstrated by staining for single-strand DNA. However, there were no signs of apoptosis in the NP or annulus fibrosus cells. Based on these findings, we hypothesized that passive cigarette smoking-induced stress stimuli first affect the CEP through blood flow due to the histological proximity, thereby stimulating chondrocyte apoptosis and reduction of the extracellular matrix (ECM). This leads to reduction of the ECM in the NP, destroying the NP matrix, which can then progress to IVD degeneration.

Modic type 1 change is an autoimmune response that requires a proinflammatory milieu provided by the 'Modic disc'

BACKGROUND CONTEXT

Modic changes (MCs) are magnetic resonance imaging (MRI) evidence of inflammatory and fibrotic vertebral bone marrow lesions that associate with adjacent disc degeneration and end plate damage. Although MC etiology is uncertain, historical data suggest a linkage to an autoimmune response of bone marrow triggered by the nucleus pulposus (NP).

PURPOSE

The aim of this study was to test whether bone marrow has an autoimmune response to NP cells that is amplified by an inflammatory milieu and ultimately leads to MC development in vivo. We hypothesized that an inflammatory co-stimulus is required for bone marrow/NP crosstalk to stimulate MC.

STUDY DESIGN

This is an in-vitro cell co-culture study plus in-vivo experiments in rat caudal vertebrae.

METHODS

In in-vitro study, bone marrow mononuclear cells (BMNCs) and NP cells (NPCs) from rats were co-cultured with and without interleukin (IL)-1α stimulation. Cell viability (n=3) of BMNCs and NPCs and gene expression (n=7) were analyzed. In in-vivo study, proinflammatory lipopolysaccharide (LPS) and control disc nucleus surrogates (NP micromass pellets) were generated in vitro from rat NPCs and implanted into rat tail vertebrae, and the response was compared with sham surgery (n=12 each). Tissue changes were investigated with T1w and T2w MRI (7T), histology, and immunohistochemistry (tumor necrosis factor, CD3) 1 (n=6) and 2 weeks (n=6) after implantation.

RESULTS

BMNC/NPC co-culture significantly increased lymphocyte viability (42%-69%, p<.05) and reduced NPC viability (96%-88%, p<.001), indicating immunogenicity of NPC. However, IL-1α was required to cause significant transcriptional upregulation of IL-1, IL-6, IL-10, and tropomyosin receptor kinase A. Therefore, an inflammatory activation is required to amplify the immune response. Immunogenicity of the NP was corroborated in vivo by CD3 cell accumulation around LPS and control disc surrogates at Day 7. However, only the LPS disc surrogate group demonstrated infiltration of CD3 cells at Day 14. Furthermore, end plate defects (p<.05, LPS: n=4/6, Ctrl: n=0/6, sham: n=0/6) and MC1-like MRI changes (T2w hyperintensity, p<.05) were only seen with LPS disc surrogates.

CONCLUSIONS

NPCs are immunogenic but cannot trigger MC without an additional proinflammatory stimulus. Our data suggest that MC requires end plate defects that allow marrow/NPC co-mingling plus an adjacent inflammatory "MC disc" that can amplify the immune response.

[Low back pain and Modic changes]

Modic changes (MCh) are pathological changes in the bone marrow and the endplates of adjacent vertebrae characterized by bone marrow edema, fatty degeneration or osteosclerosis that are revealed by high-power field magnetic resonance imaging (MRI). The dominant disease pattern is a persistent back pain syndrome with varying intensity. It leads to difficulties in the interpretation of clinical data, evaluation of MRI data and treatment. The article presents a modern conception of the pathogenesis, classification, clinical implications and treatment of MCh based on national and foreign sources as well and the author's view on the osteogenic mechanism of the pathogenesis and treatment of MCh using intraosseous blockades.

Pathobiology of Modic changes

PURPOSE

Low back pain (LBP) is the most disabling condition worldwide. Although LBP relates to different spinal pathologies, vertebral bone marrow lesions visualized as Modic changes on MRI have a high specificity for discogenic LBP. This review summarizes the pathobiology of Modic changes and suggests a disease model.

METHODS

Non-systematic literature review.

RESULTS

Chemical and mechanical stimulation of nociceptors adjacent to damaged endplates are likely a source of pain. Modic changes are adjacent to a degenerated intervertebral disc and have three generally interconvertible types suggesting that the different Modic change types represent different stages of the same pathological process, which is characterized by inflammation, high bone turnover, and fibrosis. A disease model is suggested where disc/endplate damage and the persistence of an inflammatory stimulus (i.e., occult discitis or autoimmune response against disc material) create predisposing conditions. The risk to develop Modic changes likely depends on the inflammatory potential of the disc and the capacity of the bone marrow to respond to it. Bone marrow lesions in osteoarthritic knee joints share many characteristics with Modic changes adjacent to degenerated discs and suggest that damage-associated molecular patterns and marrow fat metabolism are important pathogenetic factors. There is no consensus on the ideal therapy. Non-surgical treatment approaches including intradiscal steroid injections, anti-TNF-α antibody, antibiotics, and bisphosphonates have some demonstrated efficacy in mostly non-replicated clinical studies in reducing Modic changes in the short term, but with unknown long-term benefits. New diagnostic tools and animal models are required to improve painful Modic change identification and classification, and to clarify the pathogenesis.

CONCLUSION

Modic changes are likely to be more than just a coincidental imaging finding in LBP patients and rather represent an underlying pathology that should be a target for therapy.

Osteoclast activators are elevated in intervertebral disks with Modic changes among patients operated for herniated nucleus pulposus

PURPOSE

Modic changes (MC) are associated with low back pain (LBP). Inflammation is considered as a key factor that triggers symptoms in especially type I MC, but so far of the potential inflammatory candidates only TNFα has been linked to MC. The objective of the study was to analyze a set of inflammatory mediators in human surgical disk samples and quantify their association with MC in the adjacent vertebral bodies.

METHODS

The study sample consisted of 51 intervertebral disk tissue specimens; 20 'No MC' disks, 19 'Type I MC' disks, and 12 'Type II MC' disks. mRNA expression of 46 cytokines was quantified from isolated RNA. Tissue samples were stained using hematoxylin and eosin, toluidine blue, Herovici, CD68 and CD163.

RESULTS

No significant differences were found in the amount of macrophages or presence of chondrocyte conglomerates between the MC groups. Of the multiple genes tested, statistically significant associations were observed for M-CSF1 (p = 0.028), RANKL (p = 0.035), RUNX1 (p = 0.032), and RUNX2 (p = 0.047) that were increased in 'Type II MC,' while OSCAR (p = 0.042) was increased in 'Type I MC' group compared to 'No MC.'

CONCLUSIONS

Since these cytokines are related to differentiation and proliferation of osteoclasts, our data suggest that the stimulation of vertebral osteoclasts by factors secreted by disk tissue is involved in the pathophysiology of MC.

Role of the mitochondrial pathway in serum deprivation-induced apoptosis of rat endplate cells

The apoptosis of cartilage endplates (CEPs), acting as an initiating factor, plays a vital role in the pathogenesis of intervertebral disc degenerative diseases, the underlying molecular mechanism of the apoptotic process in CEPs is still not clear. The present study aimed to investigate the mechanism of CEP cell apoptosis. We found that low levels of fetal bovine serum (FBS) can induce cell apoptosis. Serum deprivation led to high expression levels of caspase-9, caspase-3, PARP, cytochrome-c and Bax. Flow cytometric analysis showed that inhibition of the intrinsic pathway by a caspase-9 inhibitor (z-LEHD-fmk) significantly suppressed serum deprivation-induced apoptosis. However, a caspase-8 inhibitor (z-IETD-fmk) did not reduce apoptotic cell death. These data suggest that serum deprivation induces apoptosis in rat CEP cells via the activation of the intrinsic apoptotic pathway. The efficacy of a caspase-9 inhibitor in attenuating or preventing apoptosis of serum deprivation-induced disc cell apoptosis suggests that targeting the intrinsic apoptotic pathway may be used as a potential therapy for the treatment of disc degeneration.

Severity and pattern of post-traumatic intervertebral disc degeneration depend on the type of injury

BACKGROUND CONTEXT

The burst fracture of a vertebra is the result of a complex loading procedure and is often associated with intervertebral disc (IVD) degeneration. Likewise, the presumed etiologies are (i) the structural perturbation of the IVD/end plate, (ii) the impact of loading energy alone, and (iii) the depressurization of the nucleus pulposus.

PURPOSE

To describe the pathogenesis of post-traumatic disc degeneration (DD) by comparing the severity and patterns of degeneration with different injury models.

STUDY DESIGN

New data from an in vitro organ culture study are compared with the previous work on the same model system.

METHODS

To investigate in detail the contribution of each factor (i-iii) to DD, we extended our previous work to compare three different segmental trauma processes in a rabbit full-organ in vitro model: burst fracture (Group A, etiologies i-iii), equienergetic loading without a fracture (Group B, ii), and endplate puncturing (Group C, iii). DD markers (apoptosis, necrosis, matrix remodeling, inflammation) were monitored up to 28 days posttrauma. Gene transcription data were subjected to principal component analysis and agglomerative hierarchical clustering to identify and compare pathologic patterns.

RESULTS

Only Group A showed the full profile of DD: reduced glycosaminoglycan content, increased caspase-3/7 and lactate dehydrogenase (LDH) activity, and elevated messenger RNA of catabolic (matrix metalloproteinase-1, -3, -13) and proinflammatory (tumor necrosis factor-alpha, interleukin [IL]-6, IL-8, and monocyte chemotactic protein-1) genes. In Group B, only catabolic and proinflammatory genes were slightly upregulated. In Group C, LDH but not caspase-3/7 activity was increased. Catabolic and proinflammatory genes were upregulated, although less compared with Group A. Principal component analysis revealed different transcription patterns for Group C.

CONCLUSIONS

The structural perturbation of the end plate/IVD, but not the loading energy or nuclear depressurization, promotes DD. In addition, end-plate puncturing triggers a different pathogenesis, consistent with a more continuous matrix remodeling process.

Association of endothelin-1 expression and cartilaginous endplate degeneration in humans

Background

Inflammatory cytokines are involved in intervertebral disc (IVD) degeneration. Endothelin-1 (ET-1), a 21-amino-acid cytokine implicated with cartilage degradation, is secreted by vascular endothelial cells and also by many other cell types. The expression of ET-1 in human IVD cartilage endplate (CEP) and its role in disc degeneration have not been explored.

Methods and Findings

The expression of ET-1 in degenerated CEP was analyzed by immunohistochemical staining and Western blotting; ET-1 was demonstrated in cartilaginous endplate cells (CECs) by immunofluorescent staining. The ET-1 mRNA expression and protein production by CECs stimulated by tumor necrosis factor alpha (TNF-α), a pro-inflammatory cytokine, were determined by real-time PCR analysis and Western blotting, respectively. The matrix metalloprotease-1 (MMP-1), MMP-13 and tissue inhibitor of metalloproteases-1 (TIMP-1) levels in the supernatant of cultured CECs treated with ET-1 were determined using enzyme-linked immunosorbent assays. Nitric oxide (NO) release and nitric oxide synthase (NOS) activity were measured using a spectrophotometric assay. The apoptosis of CECs by ET-1 was measured by an Annexin V-FITC detection assay. The production of ET-1 in degenerated cartilage endplate was significantly higher than normal CEP. The results showed that ET-1 was expressed by CECs and modulated by TNF-α in a dose-dependent manner. ET-1 increased production of MMP-1 and MMP-13, decreased TIMP-1 production, and induced NO and NOS release by cultured CECs. The direct stimulation of CECs by ET-1 did not promote cell apoptosis.

Conclusion

The study results suggest that ET-1 played a pivotal role in human CEP degeneration, and may be a new target for development of therapies for this condition.

Association of the polymorphism of DR4 with the risk and severity of lumbar disc degeneration in the Chinese Han population

OBJECTIVE

Death receptor 4 (DR4), an apoptosis-associated gene, plays an important role in the pathophysiology of lumbar disc degeneration (LDD). The present study aimed to determine whether the C626G polymorphism (rs4871857) of the DR4 gene is associated with the risk and severity of LDD in the Chinese Han population.

METHODS

A total of 296 patients with LDD and 208 healthy controls were enrolled in this study. The grade of disc degeneration was determined according to Schneiderman's classification for MRI. The C626G polymorphism of DR4 was genotyped using polymerase chain reaction and the restriction fragment length polymorphism method.

RESULTS

The genotype frequency of the C626G polymorphism was in agreement with the Hardy-Weinberg equilibrium (p = 0.194). The frequencies of the 626CG and GG genotypes were higher among LDD patients compared with normal controls; however, the differences were not significant. Patients with LDD showed significantly higher frequencies of the G allele than normal controls (p = 0.023). Unconditional logistic regression analysis revealed that the G allele was significantly associated with an increased risk of LDD compared with the C allele (p = 0.025; OR 1.958; 95% CI 1.087-3.526). However, no association was found between the different genotypes and the risk of LDD. In addition, the 626CG and GG genotypes, as well as the G allele were associated with higher degenerative grades of LDD compared with the CC genotype and the C allele, respectively (p = 0.005 and p < 0.001, respectively).

CONCLUSION

The C626G polymorphism of DR4 may be associated with the risk and severity of LDD in the Chinese Han population.

Negative effects of ADAMTS-7 and ADAMTS-12 on endplate cartilage differentiation

The roles of ADAMTS-7 and ADAMTS-12 in disc degeneration have not been previously examined. The purpose of this study was to examine the expression of ADAMTS-7 and ADAMTS-12 in the endplate cells isolated from patients with degenerative disc disease and to see whether they are associated with the pathological change of endplate. Sixty-four degenerated lumbar endplate specimens were obtained from the patients with degenerative disc disease categorized as type Modic I or II in magnetic resonance imaging (MRI) and 12 nondegenerative specimens as control (vertebra burst fracture patients without degenerative change in MRI) during surgical procedures. The expression of ADAMTS-7 and ADAMTS-12 was examined by real-time PCR and Western blotting. A statistically significant increase in mRNA expression of ADAMTS-7 and ADAMTS-12 was observed in the endplate cells in degenerative discs compared with nondegenerative discs. The corresponding protein levels of ADAMTS-7 and ADAMTS-12 had the same expression patterns. Moreover, ADAMTS-7 and ADAMTS-12 down-regulated the expression of Col II, Sox9, and Col X the marker genes for chondrogenesis. Our results indicate that ADAMTS-7 and ADAMTS-12 appear to be potent negative regulators of endplate cartilage development.