Downregulated interleukin 37 expression associated with aggravation of intervertebral disc degeneration

Interleukin 37 (IL-37) is an anti-inflammatory cytokine which was proven to be associated with several diseases characterized with excessive-inflammation. The pathologic process of Intervertebral disc degeneration (IVDD) is also companied by uncurbed inflammation, many cytokines were reported presenting in the process. However, there is little IL-37 related knowledge in IVDD up to now. The aim of this study was to investigate whether IL-37 expression in degenerative intervertebral disc (IVD) is different from that in non-degenerative disc and to evaluate the relationship between IL-37 expression, overexpression of pro-inflammatory cytokines and development of degeneration. Human nucleus pulposus samples were obtained from patients with disc degenerative disease and vertebra fractures undergoing discectomy and fusion. Subsequently, expression of IL-37 was assessed by real-time quantitative polymerase chain reaction (RT-PCR) and western blotting. Gene expression level was measured for IL-1α, IL-1β, IL-6, IL-16, TNF-α, TGF-β1 and Smad3. Degree of degeneration was evaluated for MRI with modified Pfirrmann grading system. The results showed that IL-37 had a decreased expression in degenerative samples compared to that in normal samples both at mRNA and protein level. Instead, significant elevated gene expression of IL-1β, IL-16, TNF-α, TGF-β1 and Smad3 were detected in degenerative samples. High correlations were observed between IL-37, IL-1β, IL-16, TGF-β1, Smad3 and degeneration degree of IVD. Downregulation of IL-37 expression appeared to result in overexpression of pro-inflammatory cytokines, such as IL-1β and IL-16, in degenerative IVD and may be a contributor involved in the progression of IVDD.     

Intervertebral disc,sensory nerves and neurotrophins: who is who in discogenic pain?

The normal intervertebral disc (IVD) is a poorly innervated organ supplied only by sensory (mainly nociceptive) and postganglionic sympathetic (vasomotor efferents) nerve fibers. Interestingly, upon degeneration, the IVD becomes densely innervated even in regions that in normal conditions lack innervation. This increased innervation has been associated with pain of IVD origin. The mechanisms responsible for nerve growth and hyperinnervation of pathological IVDs have not been fully elucidated. Among the molecules that are presumably involved in this process are some members of the family of neurotrophins (NTs), which are known to have both neurotrophic and neurotropic properties and regulate the density and distribution of nerve fibers in peripheral tissues. NTs and their receptors are expressed in healthy IVDs but much higher levels have been observed in pathological IVDs, thus suggesting a correlation between levels of expression of NTs and density of innervation in IVDs. In addition, NTs also play a role in inflammatory responses and pain transmission by increasing the expression of pain-related peptides and modulating synapses of nociceptive neurons at the spinal cord. This article reviews current knowledge about the innervation of IVDs, NTs and NT receptors, expression of NTs and their receptors in IVDs as well as in the sensory neurons innervating the IVDs, the proinflammatory role of NTs, NTs as nociception regulators, and the potential network of discogenic pain involving NTs.     

A preliminary in vitro study into the use of IL-1Ra gene therapy for the inhibition of intervertebral disc degeneration

Conventional therapies for low back pain (LBP) are purely symptomatic and do not target the cause of LBP, which in approximately 40% of cases is caused by degeneration of the intervertebral disc (DIVD). Targeting therapies to inhibit the process of degeneration would be a potentially valuable treatment for LBP. There is increasing evidence for a role for IL-1 in DIVD. A natural inhibitor of IL-1 exists, IL-1Ra, which would be an ideal molecular target for inhibiting IL-1-mediated effects involved in DIVD and LBP. In this study, the feasibility of ex vivo gene transfer of IL-1Ra to the IVD was investigated. Monolayer and alginate cultures of normal and degenerate human intervertebral disc (IVD) cells were infected with an adenoviral vector carrying the IL-1Ra gene (Ad-IL-1Ra) and protein production measured using an enzyme-linked immunosorbent assay. The ability of these infected cells to inhibit the effects of IL-1 was also investigated. In addition, normal and degenerate IVD cells infected with Ad-IL-1Ra were injected into degenerate disc tissue explants and IL-1Ra production in these discs was assessed. This demonstrated that both nucleus pulposus and annulus fibrosus cells infected with Ad-IL-1Ra produced elevated levels of IL-1Ra for prolonged time periods, and these infected cells were resistant to IL-1. When the infected cells were injected into disc explants, IL-1Ra protein expression was increased which was maintained for 2 weeks of investigation. This in vitro study has shown that the use of ex vivo gene transfer to degenerate disc tissue is a feasible therapy for the inhibition of IL-1-mediated events during disc degeneration.     

Expression of receptors for putative anabolic growth factors in human intervertebral disc: implications for repair and regeneration of the disc

Low back pain (LBP) is a common, debilitating and economically important disorder. Current evidence implicates loss of intervertebral disc (IVD) matrix consequent upon 'degeneration' as a major cause of LBP. Degeneration of the IVD involves increases in degradative enzymes and decreases in the extracellular matrix (ECM) component in a process that is controlled by a range of cytokines and growth factors. Studies have suggested using anabolic growth factors to regenerate the normal matrix of the IVD, hence restoring disc height and reversing degenerative disc disease. However, for such therapies to be successful it is vital that the target cells (i.e. the disc cells) express the appropriate receptors. This immunohistochemical study has for the first time investigated the expression and localization of four potentially beneficial growth factor receptors (i.e. TGFbetaRII, BMPRII, FGFR3 and IGFRI) in non-degenerate and degenerate human IVDs. Receptor expression was quantified across regions of the normal and degenerate disc and showed that cells of the nucleus pulposus (NP) and inner annulus fibrosus (IAF) expressed significantly higher levels of the four growth factor receptors investigated. There were no significant differences between the four growth factor expression in non-degenerate and degenerate biopsies. However, expression of TGFbetaRII, FGFR3 and IGFRI, but not BMP RII, were observed in the ingrowing blood vessels that characterize part of the disease aetiology. In conclusion, this study has demonstrated the expression of the four growth factor receptors at similar levels in the chondrocyte-like cells of the NP and IAF in both non-degenerate and degenerate discs, implicating a role in normal disc homeostasis and suggesting that the application of these growth factors to the degenerate human IVD would stimulate matrix production. However, the expression of some of the growth factor receptors on ingrowing blood vessels might be problematic in a therapeutic approach.     

椎间盘源性下腰痛的组织病理学变化

背景：椎间盘源性下腰痛是一种椎间盘外周部基本保持完整,而内部各种病理(退变、终板损伤、炎症等)刺激椎间盘内疼痛感受器引起的功能丧失性下腰痛,并且不伴有根性症状,无神经或节段过度活动的放射学证据。 目的：综述了椎间盘源性下腰痛病理变化、临床诊断的特异性、敏感性和安全性以及各种诊断方法存在的争议观点。 方法：应用计算机检索中国期刊全文数据库、PubMed 数据库、EMBASE数据库1970/2010 有关椎间盘源性下腰痛诊断的文献,排除重复性研究。 结果与结论：共保留42篇文献归纳总结。目前临床上根据椎间盘源性下腰痛的病理变化有多种诊断方法,包括物理检查的中心化趋势和骨震动测试,MRI上的黑间盘、高密度区、Modic 改变,椎间盘超声检查,血清学中的高敏感性C-反应蛋白和椎间盘造影。其中腰椎间盘造影有较高的敏感性和特异性,是目前首选的诊断方法。     

Intervertebral disc ageing and degeneration: The antiapoptotic effect of oestrogen

As an important part of the spinal column, the intervertebral disc (IVD) plays an important role in the intervertebral juncture and spinal movement in general. IVD degeneration (IVDD), which mimics disc ageing but at an accelerated rate, is a common and chronic process that results in severe spinal symptoms, such as lower back pain. It is generally assumed that lower back pain caused by IVDD can also develop secondary conditions, including spinal canal stenosis, spinal segmental instability, osteophyte formation, disc herniation and spinal cord and nerve root compression. Over the past few years, many researchers around the world have widely studied the relevance between oestrogen and IVDD, indicating that oestrogen can effectively alleviate IVDD development by inhibiting the apoptosis of IVD cells. Oestrogen can decrease IVD cell apoptosis in multiple ways, including the inhibition of the inflammatory cytokines IL-1β and TNF-α, reducing catabolism because of inhibition of matrix metalloproteinases, upregulating integrin α₂β₁ and IVD anabolism, activating the PI3K/Akt pathway, decreasing oxidative damage and promoting autophagy. In this article, we perform an overview of the literature regarding the antiapoptotic effect of oestrogen in IVDD.     

MicroRNA-16 inhibits the lipopolysaccharide-induced inflammatory response in nucleus pulposus cells of the intervertebral disc by targeting TAB3

IntroductionA variety of inflammatory mediators are produced by the degenerative human intervertebral disc (IVD) tissues spontaneously, suggesting their role in the development of intervertebral disc degeneration (IDD). Our present study was designed to investigate the regulatory effect of microRNA-16 (miR-16) on the lipopolysaccharide (LPS)-induced inflammatory response in nucleus pulposus (NP) cells of the IVD.Material and methodsNP cells were treated with LPS to induce inflammatory responses. The expression of miRNA and genes was determined by qRT-PCR. Western blot and an ELISA kit were used to detect the proteins and protein expression, respectively. A dual luciferase reporter assay was applied to identify the correlation between a miRNA and a gene, and to test nuclear factor-κB (NF-κB) activity.ResultsThe results suggested that miR-16 positively regulated the mRNA and protein expression of extracellular matrix (ECM) genes (including aggrecan and collagen II) in NP cells, while it was negatively correlated with ECM degrading enzymes (including MMP3, MMP13, ADAMTS4, ADAMTS5) and related genes of nitric oxide (NO) reaction. Further studies revealed that miR-16 could oppositely regulate NF-κB and MAPK pathways by directly mediating their upstream gene TAB3.ConclusionsOur study suggested that, in NP cells of the IVD, miR-16 could exert inhibitory effects on the LPS-induced inflammatory response through NF-κB and MAPK pathways by directly mediating TAB3. In this way, miR-16 would play a protective role against LPS-induced IDD and inflammation. Therefore, miR-16 may be a novel therapeutic target for the inhibit of the ECM in the IVD.     

椎间盘源性腰痛的诊断及治疗进展

椎间盘源性腰痛是慢性腰痛的常见类型,是导致残疾的首要原因之一,给社会带来了巨大的经济负担。由于椎间盘解剖结构的特殊性,目前关于椎间盘源性腰痛的具体机制尚不清楚,其诊断及治疗尚未达成统一共识。国内外对于椎间盘源性腰痛的治疗主要包括保守治疗及外科手术治疗,治疗的目的是缓解临床症状,而不是从根本上逆转椎间盘退变。近年来生物治疗开始兴起,为椎间盘源性腰痛的治疗提供了新的方向,但国内关于生物治疗的相关研究报道较少。本文就椎间盘源性腰痛的诊断及治疗进展作一综述,以期为临床提供相关参考。     

软骨终板形态与椎间盘退变的相关性

背景：以往研究证明多种内环境因素共同作用引发椎间盘退变,最重要的机制为椎间盘软骨终板的退变。 目的：分析椎间盘退变与终板形态的关系。 方法：回顾性分析62例因椎间盘源性慢性下腰痛和79例因髓核脱出致神经根性症状患者的腰椎MRI正中矢状位图像资料。根据腰椎MRI正中矢状位T1W1图像确定终板形态,T2W1图像确定椎间盘退变程度分级。 结果与结论：平坦型和不规则型终板最常见于椎间盘退变人群下腰椎,L5/S1平坦型最多见。髓核脱出组与椎间盘源性慢性下腰痛组中凹陷型终板椎间盘退变程度均较平坦型、不规则型低,平坦型终板椎间盘退变程度较不规则型低(P < 0.01)。两组间凹陷型与不规则型终板椎间盘退变程度差异无显著性意义,髓核脱出组平坦型椎间盘退变程度较椎间盘源性慢性下腰痛组高(P < 0.05)。提示随着椎间盘退变程度的加重,软骨终板形态有由凹陷型向平坦型、不规则型依次转变的趋势。     

Ganoderic Acid A Attenuates IL-1β-Induced Inflammation in Human Nucleus Pulposus Cells Through Inhibiting the NF-κB Pathway

Inflammation - Intervertebral disc (IVD) degeneration is a major cause of low back pain associated with several pathological changes in the IVD, including dysfunction of nucleus pulposus (NP)...     

Biologic Response of Degenerative Living Human Nucleus Pulposus Cells to Treatment with Cytokines

Purpose

To investigate the molecular responses of various genes and proteins related to disc degeneration upon treatment with cytokines that affect disc-cell proliferation and phenotype in living human intervertebral discs (IVDs). Responsiveness to these cytokines according to the degree of disc degeneration was also evaluated.

Materials and Methods

The disc specimens were classified into two groups: group 1 (6 patients) showed mild degeneration of IVDs and group 2 (6 patients) exhibited severe degeneration of IVDs. Gene expression was analyzed after treatment with four cytokines: recombinant human bone morphogenic protein (rhBMP-2), transforming growth factor-β (TGF-β), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α). Molecular responses were assessed after exposure of cells from the IVD specimens to these cytokines via real-time polymerase chain reaction and immunofluorescence staining.

Results

mRNA gene expression was significantly greater for aggrecan, type I collagen, type II collagen, alkaline phosphatase, osteocalcin, and Sox9 in group 1 than mRNA gene expression in group 2, when the samples were not treated with cytokines. Analysis of mRNA levels for these molecules after morphogen treatment revealed significant increases in both groups, which were much higher in group 1 than in group 2. The average number of IVD cells that were immunofluorescence stained positive for alkaline phosphatase increased after treatment with rhBMP-2 and TGF-β in group 1.

Conclusion

The biologic responsiveness to treatment of rhBMP-2, TGF-β, TNF-α, and IL-1β in the degenerative living human IVD can be different according to the degree of degeneration of the IVD.     

Tissue-engineering approach to regenerating the intervertebral disc

In today's world there is an ever increasing incidence of low back pain, which is generally attributed to degeneration of the intervertebral disc (IVD) in those in their second or third decade of life. The most prevalent treatment modalities involve conservative methods (physical therapy and medications) or surgical fusion of the upper and lower vertebral bodies. In the last 10 years, there has been a surge of interest in applying tissue-engineering principles to treat spinal problems associated with the IVD. Tissue engineering provides many promising advantages to treating disc degeneration; it adopts a more biological and reparative approach, whereby the main goal is to restore the properties of the disc to its pre-degenerative state. This review outlines the physiology of the IVD and the etiology of disc degeneration. Much of the research carried out in the field of tissue engineering is based on three predominant constituents: cells, scaffolds, and signals. Thus, specific attention is given to these constituents and their potential use in repairing the IVD. Some of the significant challenges involved in IVD tissue engineering are also identified, and a brief discussion regarding possible future areas of research follows.     

Degeneration alters structure-function relationships at multiple length-scales and across interfaces in human intervertebral discs

Intervertebral disc (IVD) degeneration and associated back pain place a significant burden on the population. IVD degeneration is a progressive cascade of cellular, compositional, and structural changes, which results in a loss of disc height, disorganization of extracellular matrix architecture, tears in the annulus fibrosus which may involve herniation of the nucleus pulposus, and remodeling of the bony and cartilaginous endplates (CEP). These changes to the IVD often occur concomitantly, across the entire motion segment from the disc subcomponents to the CEP and vertebral bone, making it difficult to determine the causal initiating factor of degeneration. Furthermore, assessments of the subcomponents of the IVD have been largely qualitative, with most studies focusing on a single attribute, rather than multiple adjacent IVD substructures. The objective of this study was to perform a multiscale and multimodal analysis of human lumbar motion segments across various length scales and degrees of degeneration. We performed multiple assays on every sample and identified several correlations between structural and functional measurements of disc subcomponents. Our results demonstrate that with increasing Pfirrmann grade there is a reduction in disc height and nucleus pulposus T2 relaxation time, in addition to alterations in motion segment macromechanical function, disc matrix composition and cellular morphology. At the cartilage endplate-vertebral bone interface, substantial remodeling was observed coinciding with alterations in micromechanical properties. Finally, we report significant relationships between vertebral bone and nucleus pulposus metrics, as well as between micromechanical properties of the endplate and whole motion segment biomechanical parameters, indicating the importance of studying IVD degeneration as a whole organ.     

The role of nerve fibers and their neurotransmitters in regulating intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) has been the major contributor to chronic lower back pain (LBP). Abnormal apoptosis, senescence, and pyroptosis of IVD cells, extracellular matrix (ECM) degradation, and infiltration of immune cells are the major molecular alternations during IVDD. Changes at tissue level frequently occur at advanced IVD tissue. Ectopic ingrowth of nerves within inner annulus fibrosus (AF) and nucleus pulposus (NP) tissue has been considered as the primary cause for LBP. Innervation at IVD tissue mainly included sensory and sympathetic nerves, and many markers for these two types of nerves have been detected since 1940. In fact, in osteoarthritis (OA), beyond pain transmission, the direct regulation of neuropeptides on functions of chondrocytes have attracted researchers’ great attention recently. Many physical and pathological similarities between joint and IVD have shed us the light on the neurogenic mechanism involved in IVDD. Here, an overview of the advances in the nervous system within IVD tissue will be performed, with a discussion on in the role of nerve fibers and their neurotransmitters in regulating IVDD. We hope this review can attract more research interest to address neuromodulation and IVDD itself, which will enhance our understanding of the contribution of neuromodulation to the structural changes within IVD tissue and inflammatory responses and will help identify novel therapeutic targets and enable the effective treatment of IVDD disease.     

腰椎Modic改变中炎性细胞因子的效应

背景：椎间盘退变和终板异常可能是椎间盘源性下腰痛的病因,大量文献报道,炎性细胞因子在腰椎退变性疾病中发挥着极其重要的作用。 目的：综述炎性细胞因子在腰椎Modic改变中的研究进展。 方法：应用计算机检索2010-01/2011-09中国生物医学文献服务系统相关文章,检索词为“modic改变,椎体终板”,并限定文章语言种类为中文。同时计算机检索PubMed数据库相关文章,检索词为“modic,vertebral endplate”,并限定文章语言种类为English。共检索到文献48篇,最终纳入符合标准的文献30篇。 结果与结论：腰椎Modic改变是指腰椎终板及终板下骨质在MRI上的异常信号改变,其病变机制目前不是十分清楚。有文献证实退变椎间盘髓核内部炎性物质(肿瘤坏死因子/神经标志物蛋白质基因产物/白细胞介素)的产生,通过终板扩散可导致终板局部炎症,引发终板退变。近年来随着分子生物学和分子免疫学的迅速发展以及对细胞因子和炎症递质研究的深入,细胞因子和炎症递质在腰椎终板退变中的作用越来越受到重视,目前对于细胞因子和炎性递质在腰椎Modic改变中的作用正在进一步的深入中。     

Sesamin inhibits lipopolysaccharide-induced inflammation and extracellular matrix catabolism in rat intervertebral disc

Intervertebral disc (IVD) degeneration contributes to most spinal degenerative diseases, while treatment inhibiting IVD degeneration is still in the experimental stage. Sesamin, a bioactive component extracted from sesame, has been reported to exert chondroprotective and anti-inflammatory effects. Here, we analyzed the anti-inflammatory and anti-catabolic effects of sesamin on rat IVD in vitro and ex vivo. Results show that sesamin significantly inhibits the lipopolysaccharide (LPS)-induced expression of catabolic enzymes (MMP-1, MMP-3, MMP-13, ADAMTS-4, ADAMTS-5) and inflammation factors (IL-1β, TNF-α, iNOS, NO, COX-2, PGE2) in a dose-dependent manner in vitro. It is also proven that migration of macrophages induced by LPS can be inhibited by treatment with sesamin. Organ culture experiments demonstrate that sesamin protects the IVD from LPS-induced depletion of the extracellular matrix ex vivo. Moreover, sesamin suppresses LPS-induced activation of the mitogen-activated protein kinase (MAPK) pathway through inhibiting phosphorylation of JNK, the common downstream signaling pathway of LPS and IL-1β, which may be the potential mechanism of the effects of sesamin. In light of our results, sesamin protects the IVD from inflammation and extracellular matrix catabolism, presenting positive prospects in the treatment of IVD degenerative diseases.