Carbohydrate metabolism and concentration profiles of solutes in the canine lumbar intervertebral disc

Utilization of glucose and oxygen by the cells as well as concentration profiles of solutes were studied in the canine intervertebral disc. Cell metabolism in this avascular tissue, being predominantly anaerobic, was found to be dependent on oxygen tension (this being especially pronounced in the region of 0.13-0.4 kPa (1-3 mmHg). A high production rate of lactic acid was found in the nucleus pulposus, whereas towards the periphery of the annulus fibrosus this rate gradually decreased. In the centrally located areas of the disc tissue, far away from the blood circulation, the highest concentrations of lactic acid were found. For the normal disc the energy demands seem to be met as even small amounts of oxygen account for a large energy source, whereas the cellular requirements are balanced up predominantly by glucose. In regions with extremely low oxygen tensions large amounts of glucose are consumed, but an additional potential energy pool of glycogen seems to be available.     

椎间盘突出患者椎间盘Fas基因的表达

背景：临床中发现腰椎间盘突出症常在一个家族中多人甚至全部发病,而且发病的部位、原因、症状基本一致,这表明基因在该种病症中扮演着重要的角色。 目的：分析家族性腰椎椎间盘突出症患者椎间盘内Fas凋亡基因表达的特点。 方法：用半定量RT-PCR方法检测15例家族性腰椎椎间盘突出患者、21例普通椎间盘突出患者、5例新鲜尸体椎间盘的软骨终板和髓核组织中Fas基因的表达情况。 结果与结论：家族性椎间盘突出与普通椎间盘突出患者终板内Fas基因的表达均高于新鲜尸体椎间盘终板内Fas基因的表达,差异有显著性意义(P < 0.05),家族性椎间盘突出与普通椎间盘突出患者终板内Fas基因的表达差异无显著性意义(P > 0.05)。家族性椎间盘突出患者髓核内Fas基因表达与普通椎间盘突出患者、新鲜尸体髓核内Fas基因表达相比较,差异无显著性意义(P > 0.05)。结果可见家族性椎间盘终板中Fas基因的表达增加可能是继发性的,可以通过阻止终板退变来达到阻止椎间盘退变的目的。     

椎间盘退变的机制及修复

背景：目前为止,椎间盘退变源性腰痛的发病机制研究并不十分清楚明了,对于其治疗的手段也多种多样,但效果不一。目的：综述近年国内外椎间盘退变机制及修复的研究进展。方法：由第一作者检索至2014年11月为止 PubMed数据(http://www.ncbi.nlm.nih.gov/PubMed)及CNKI中国期刊全文数据库(http://www.cnki.net/),以“椎间盘退变因素,椎间盘源性腰痛,椎间盘退变治疗”等为检索词,共检索到78篇相关文献,排除重复研究,共30篇文献符合纳入标准。结果与结论：综合大量国内外科研人员对椎间盘退变的研究,目前比较推崇的退变因素包括形态学上的改变、炎性递质和细胞外基质的变化、生长因子的作用等,治疗上仍处于对其形态学的修复方面,其中经皮穿刺椎间盘减压、椎体融合、人工椎间盘置换、动态稳定系统等手术治疗方法对椎间盘退变引起的症状有确切的疗效。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Human intervertebral disc: structure and function

This review begins with a brief introduction in which the development, blood supply and innervation of the intervertebral disc is considered, particularly as these may influence the following sections on structure and function. The three regions within the disc--that is, the nucleus pulposus, annulus fibrosus, and cartilage end plates--are considered in some detail. There appears to be no distinct border between the central nucleus pulposus and the outer annulus fibrosus, the main difference being in their fibrous structure. The fluid space is important in the nutrition of the disc, showing plastic deformation and recovery characteristics. The structural elements, both macroscopically and microscopically, together with the biochemical elements, are intimately related to function. The intervertebral disc should not be though of as a homogeneous and static structure; it has a heterogeneous composition and responds dynamically to applied loads. Neither should it be considered as an isolated structure because it interacts with the vertebral bodies, together constituting the vertebral unit. Furthermore, changes within the disc can, and do, have dramatic effects on vertebral column kinematics. The intervertebral disc is not inactive; it is capable of self-maintenance; in injury it can repair itself and has considerable regenerative properties.     

Hierarchical structure of the intervertebral disc

Optical microscope techniques are used to characterize the hierarchical structure of the collagenous components of the human intervertebral disc. In the anterior annulus fibrosus, the thickness of lamellae increases abruptly 2 mm inward from the edge of the disc, dividing the annulus into peripheral and transitional regions. Lamellae in the lateral and posterior aspects of the disc have a broad distribution of lamellar thicknesses throughout the annulus. In alternating lamellae, fibers are inclined with respect to the vertical axis of the spine in a layup structure. From the edge of the disc inward to the nucleus, this interlamellar angle decreases from +62 to +45 degrees. Within lamellae, the collagen fibers exhibit a planar crimped morphology. The plane of the waveform is inclined with respect to the vertical axis by the interlamellar angle. From the edge of the disc inward, the crimp angle increases from 20 to 45 degrees and the crimp period decreases from 26 to 20 um. A hierarchical model of the intervertebral disc has been developed that incorporates these morphological gradients.     

Smoking and intervertebral disc degeneration

Cigarette smokers have an increased risk of low back pain which may be caused by disc degeneration and spinal instability, for example. Ischemia, apoptosis, faulty synthesis of disc macromolecules, and an imbalance between disc matrix proteinases and their inhibitors may be involved in the pathogenesis of disc degeneration. Along with degeneration, the primary avascular disc turns vascular. There is some evidence that disc degeneration of cigarette smokers is of more severe degree than that of non-smokers.Cigarette-smoking increases serum proteolytic activity by releasing proteolytic enzymes from neutrophils in alveolar capillaries, and by inhibiting the activity of alpha-1-antiprotease, the most potent protease inhibitor.We hypothesize that the high serum proteolytic activity of cigarette-smokers gets access to a previously degenerated neovascularized disc and speeds up the degerative process. The increased proteolytic activity may also weaken the spinal ligaments resulting in spinal instability. These processes may explain the increased risk of low back pain of cigarette smokers.     

Inhibition of vertebral endplate perfusion results in decreased intervertebral disc intranuclear diffusive transport

Impaired nutrition of the intervertebral disc has been hypothesized to be one of the causes of disc degeneration. However, no causal relationship between decreased endplate perfusion and limited nutrient transport has been demonstrated to support this pathogenic mechanism. To determine the importance of endplate perfusion on solute diffusion into the nucleus pulposus and to show causality of endplate perfusion on intranuclear diffusion in large animal lumbar intervertebral discs, diffusive transport into ovine lumbar intervertebral discs was evaluated after inhibiting adjacent vertebral endplate perfusion. Partial perfusion blocks were created in vertebrae close and parallel to both endplates of lumbar discs of anaesthetized sheep. To assess diffusivity of small molecules through the endplate, N2O was introduced into the inhalation gas mixture and concentrations of intranuclear N2O were measured for 35 min thereafter. Post mortem, procion red was infused through the spinal vasculature and perfusion through the endplate was assessed by quantifying the density of dye-perfused endplate vascular buds in histology sections. Perfusion of the endplates overlying the nucleus pulposus was inhibited by almost 50% in the partially blocked discs relative to the control discs. There was also a nine-fold decreased transport rate of intranuclear N2O in partially blocked discs compared with control discs. The density of perfused endplate vascular buds correlated significantly to the amount of transported intranuclear N2O (r2 = 0.52, P = 0.008). The vertebral endplate was demonstrated to be the main route of intravascular solute transport into the nucleus pulposus of intervertebral discs, and inhibition of endplate perfusion can cause inhibited solute transport into the disc intranuclear tissue.     

Diversity of intervertebral disc cells: phenotype and function

The intervertebral disc (IVD) is a moderately moving joint that is located between the bony vertebrae and provides flexibility and load transmission throughout the spinal column. The disc is composed of different but interrelated tissues, including the central highly hydrated nucleus pulposus (NP), the surrounding elastic and fibrous annulus fibrosus (AF), and the cartilaginous endplate (CEP), which provides the connection to the vertebral bodies. Each of these tissues has a different function and consists of a specific matrix structure that is maintained by a cell population with distinct phenotype. Although the healthy IVD is able to balance the slow matrix turnover of synthesis and degradation, this balance is often disturbed, leading to degenerative disorders. Successful therapeutic management of IVD degeneration requires a profound understanding of the cellular and molecular characteristics of the functional IVD. Hence, the phenotype of IVD cells has been of significant interest from multiple perspectives, including development, growth, remodelling, degeneration and repair. One major challenge that complicates our understanding of the disc cells is that both the cellular phenotype and the extracellular matrix strongly depend on disc maturity and health and as a consequence are continuously evolving. This review delineates the diversity of the cell types found in the intervertebral disc, with emphasis on human, but with reference to other species. The cells of the NP appear rounded and express a proteoglycan-rich matrix, whereas the more elongated AF cells are embedded in a collagen fibre matrix and the CEPs represent a layer of cartilage. Even though all disc cells have often been referred to as ‘intervertebral disc chondrocytes’, distinct phenotypical differences in comparison with articular chondrocytes exist and have been reported recently. The availability of more specific markers has also improved our understanding of progenitor cell differentiation towards an IVD cell phenotype. Ultimately, new cell- and tissue-engineering approaches to regenerative therapies will only be successful if the specific characteristics of the individual tissues and their context in the function of the whole organ, are taken into consideration.     

Genetics of intervertebral disc disease: A review

Intervertebral disc disease (IVDD) is a common musculoskeletal disease affecting about 5% of all individuals. It is characterized by lumbar disc herniation, which causes nerve root irritation, either mechanically or via inflammatory mediators, and results in radiating pain, known as sciatica. Numerous studies have been conducted to identify the causes and risk factors for IVDD. Lifting heavy loads, torsional stress, and motor vehicle driving are among the best-identified environmental risk factors. However, it has become evident recently from family and twin studies that genetic factors may also be important in IVDD. This hypothesis was strengthened by the identification of two collagen IX alleles associated with sciatica and lumbar disc herniation. In addition, disc degeneration has been shown to be related to an aggrecan gene polymorphism, a Vitamin D receptor and matrix metalloproteinase-3 gene alleles. This review highlights the genetic role and occupational aspects of IVDD.     

Swelling of the intervertebral disc in vitro

Slices of the intervertebral disc swell rapidly in aqueous solutions. Following swelling, a large proportion of the proteoglycans leach out. These changes can introduce artifacts into in vitro experimental work. Swelling results from the large Gibbs-Donnan osmotic pressure of the proteoglycans which the collagen network of the disc is unable to oppose alone. Swelling can be prevented by applying pressure to disc slices either mechanically or with iso-osmotic solutions.     

Antenatal differentiation of the human intervertebral disc

Summary To study the antenatal differentiation of the human intervertebral disc, the columns of forty eight embryos and fetuses were examined histologically. The primitive disc is composed of two structures: the notochord which shows a progressive expansion into the disc, and the fibrocartilaginous perinotochordal disc. No histological sign of interaction between notochordal and perinotochordal cells, which may explain the notochordal expansion into the discs, was seen. On the other hand, the notochordal intervention in the cartilaginous differentiation of the inner zone is probable.

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Différenciation anténatale du disque intervertébral humain

Résumé Cette étude de la différenciation anténatale du disque intervertébral humain repose sur l'examen de coupes histologiques de quarante huit colonnes vertébrales d'embryons et de foetus. Le disque primitif est composé de deux structures : la notochorde, qui présente une expansion progressive de son diamètre au sein du disque, et le disque périnotochordal, d'abord mésenchymateux puis fibrocartilagineux. Il n'a pas été mis en évidence de signe histologique témoignant d'une interaction entre les cellules notochordales et les cellules périnotochordales qui puisse expliquer l'expansion de la notochorde au sein des disques. Le rôle de la notochorde dans la différenciation cartilagineuse de la zone centrale est par contre probable.

     

Strategies for regeneration of the intervertebral disc

Low back pain resulting from degenerative disc disease is the most common cause of disability in the UK. Current low back pain treatments are aimed at either treating the symptoms of pain, or removing the source of pain itself, but do not address the biological basis of the disease. Our increasing understanding of the molecular biological basis for degenerative disc disease has enabled the development of strategies aimed at tackling the causes of degeneration. Here we review the progress that has been made in strategies using cells, biomaterials and growth factors aimed at regenerating the human intervertebral disc.     

椎间盘微环境下椎间盘源性干细胞和髓核间充质干细胞的活性

文题释义：椎间盘微环境：在正常情况下,髓核组织缺乏血液供应,其营养代谢主要依赖渗透。由于代谢产物等影响,椎间盘组织内部的pH值为6.9-7.2,被认为是人体内最恶劣的环境之一,在这种条件下细胞正常代谢能力受到很大抑制,即使是特化的髓核细胞其代谢率也仅为正常的32%。当椎间盘退变后,葡萄糖及氧浓度进一步下降,乳酸堆积,pH值降低和代谢产物进行性增加。 髓核间充质干细胞：经过前期实验发现髓核间充质干细胞经自体移植于椎间盘局部,可以分化为纤维环细胞和髓核细胞,或者通过旁分泌细胞因子来促进组织细胞的再生,但髓核间充质干细胞在椎间盘微环境中存活量级并不清楚。椎间盘源性干细胞和髓核间充质干细胞在椎间盘微环境下的生存变化差异性也还是未知。 背景：椎间盘微环境对干细胞生物学行为具有重要作用,拟通过微环境调节作用来实现不依赖种子细胞的椎间盘组织修复。 目的：探讨椎间盘微环境下椎间盘源性干细胞和髓核间充质干细胞活性的差异。 方法：健康雄性SD大鼠10只,按照解剖区分离椎间盘骨组织,用Ⅱ型胶原酶消化后进行体外培养椎间盘源性干细胞;分离髓核组织,采用酶消化法体外培养髓核间充质干细胞。将获得的椎间盘源性干细胞和髓核间充质干细胞在体外进行正常条件、椎间盘微环境条件下培养扩增,培养第1-6天采用MTT法测定细胞增殖情况,培养第1,3,6天采用流式细胞技术检测CD29阳性表达水平。 结果与结论：①在不同环境的培养条件下,椎间盘源性干细胞和髓核间充质干细胞增殖情况呈相反趋势。在正常培养条件下,椎间盘源性干细胞和髓核间充质干细胞呈增殖状态,第4-6天为对数增殖期,两者差异无显著性意义(P > 0.05);在椎间盘微环境条件下,髓核间充质干细胞的增殖活性明显低于椎间盘源性干细胞,差异有显著性意义(P < 0.05);②在椎间盘微环境条件下培养第3,6天,椎间盘源性干细胞表面CD29阳性抗原表达水平明显高于髓核间充质干细胞,差异有显著性意义(P < 0.05);③结果表明,在椎间盘微环境条件下,髓核间充质干细胞和椎间盘源性干细胞活性受到一定程度的抑制,但椎间盘源性干细胞较髓核间充质干细胞保留更多的细胞活性。 ORCID: 0000-0002-3582-5630(胡炜) 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

Magnetic resonance imaging and spectroscopy of the intervertebral disc

Intervertebral disc disease is an emerging health concern and has a considerable negative effect on the economy and on society. MRI has a critical role in assessing the disc, but it is still a challenge to objectively correlate disc health and pain with images. In this paper, a review of MR disc imaging techniques including grading, relaxation time measurements, diffusion, and contrast perfusion is presented. In addition, high-resolution magic-angle spinning methods to correlate in vitro disc degeneration (with pain, etc) are discussed. With the potential for gaining morphological and biochemical information, MRI shows promise for quantitative assessment of disc health.     

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.     

综合疗法治疗腰椎间盘突出症

本文对67例腰椎间盘突出症住院患者采用牵引为主,辅以按摩、针灸、超短波治疗,并配合中药口服,进行综合疗法的治疗。三疗程后,取得满意疗效,总有效率87.5%,且12个月及24个月的复发率低,均优于单一疗法,为临床治疗腰椎间盘突出症的物理治疗提供了值得探讨的新思路。     

Improving the fixation of an artificial intervertebral disc

The fixation of an artificial intervertebral disc has been studied especially with respect to the dimensions, the convexity of the endplates and the size of the fixation elements. From literature and cadaveric vertebrae, the dimensions and shape of the lumbar vertebral endplates were determined and the dimensions of fixation ribs for the artificial intervertebral disc were calculated. To withstand shear forces and prevent dislocation, two sagittal ribs, each 3.5 mm in height and at least 20 mm in length and four transversal ribs, each 1.5 mm in height and with a total length of 60 mm are sufficient. A range of five different sagittal diameters was selected as sufficient for all patients. At least 72.6 % of the endplate of the vertebrae is covered. A convexity with a radius of 140 mm limits the gap to 0.62 mm.