Background

Signalling by growth differentiation factor 6 (GDF6/BMP13) has been implicated in the development and maintenance of healthy NP cell phenotypes and GDF6 mutations are associated with defective vertebral segmentation in Klippel-Feil syndrome. GDF6 may thus represent a promising biologic for treatment of IVD degeneration. This study aimed to investigate the effect of GDF6 in human NP cells and critical signal transduction pathways involved.

Background. Magnetic resonance imaging (MRI) algorithm identifies end stage severely degenerated disc as ‘black’, and a moderately degenerate to non-degenerated disc as ‘white’. MRI is based on signal intensity changes that identifies loss of proteoglycans, water, and general radial bulging but lacks association with microscopic features such as fissure, endplate damage, persistent inflammatory catabolism that facilitates proteoglycan loss leading to ultimate collapse of annulus with neo-innervation and vascularization, as an indicator of pain. Thus, we propose a novel machine learning based imaging tool that combines quantifiable microscopic histopathological features with macroscopic signal intensities changes for hybrid assessment of disc degeneration. Methods. 100-disc tissue were collected from patients undergoing surgeries and cadaveric controls, age range of 35–75 years. MRI Pfirrmann grades were collected in each case, and each disc specimen were processed to identify the 1) region of interest 2) analytical imaging vector 3) data assimilation, grading and scoring pattern 4) identification of machine learning algorithm 5) predictive learning parameters to form an interface between hardware and software operating system. Results. Kernel algorithm defines non-linear data in xy histogram. X,Y values are scored histological spatial variables that signifies loss of proteoglycans, blood vessels ingrowth, and occurrence of tears or fissures in the inner and outer annulus regions mapped with the dampening and graded series of signal intensity changes. Conclusion. To our knowledge this study is the first to propose a machine learning method between microscopic spatial tissue changes and macroscopic signal intensity grades in the intervertebral disc. No conflict of interest declared.  . Sources of Funding. ICMR/5/4-5/3/42/Neuro/2022-NCD-1, Dr TMA PAI SMU/ 131/ REG/ TMA PURK/ 164/2020. A part of the above study was presented as an oral paper at the International Society for the Study of Lumbar Spine (ISSLS) meeting held on 1–5. th. May 2023, Melbourne, Australia

The belief that an intervertebral disc must degenerate before it can herniate has clinical and medicolegal significance, but lacks scientific validity. We hypothesised that tissue changes in herniated discs differ from those in discs that degenerate without herniation. Tissues were obtained at surgery from 21 herniated discs and 11 non-herniated discs of similar degeneration as assessed by the Pfirrmann grade. Thin sections were graded histologically, and certain features were quantified using immunofluorescence combined with confocal microscopy and image analysis. Herniated and degenerated tissues were compared separately for each tissue type: nucleus, inner annulus and outer annulus. Herniated tissues showed significantly greater proteoglycan loss (outer annulus), neovascularisation (annulus), innervation (annulus), cellularity/inflammation (annulus) and expression of matrix-degrading enzymes (inner annulus) than degenerated discs. No significant differences were seen in the nucleus tissue from herniated and degenerated discs. Degenerative changes start in the nucleus, so it seems unlikely that advanced degeneration caused herniation in 21 of these 32 discs. On the contrary, specific changes in the annulus can be interpreted as the consequences of herniation, when disruption allows local swelling, proteoglycan loss, and the ingrowth of blood vessels, nerves and inflammatory cells. In conclusion, it should not be assumed that degenerative changes always precede disc herniation. Cite this article: Bone Joint J 2013;95-B:1127–33

Purpose of study and background. Mechanical overloading initiates intervertebral disc degeneration, presumably because cells break down the extracellular matrix (ECM). We used Fourier Transform Infrared Spectroscopy (FTIR) imaging to identify, visualize and quantify the ECM and aimed to identify spectroscopic markers for early disc degeneration. Methods and Results. In seven goats, one disc was injected with chondroitinase ABC (mild degeneration) and after three months compared to control. Ex vivo, 50 caprine discs received physiological loading (50–150N) or overloading (50–400N) in a loaded disc culture system. To determine whether ECM degeneration is due to cell activity, half of the discs was subjected to freeze-thaw cycles. Spectroscopic images were collected at 1000–1300 cm. −1. and analyzed using multivariate curve resolution analysis. In vivo, less proteoglycan was found in the degenerated group (p<0.05), especially in the nucleus. Collagen content was increased in the nucleus and anterior annulus, and had higher entropy (p<0.01), indicating matrix disorganization. In the ex vivo experiment, the proteoglycan/collagen ratio was decreased (p<0.05) in the vital group and there was an increase in collagen entropy (p<0.05). A significant interaction between loading and vitality was found in the amount of collagen (p<0.05), but not in the entropy. Conclusion. Three weeks of mild overloading causes measurable changes in the extracellular matrix. Increased collagen entropy indicates that remodeling of collagen is a first step into disc degeneration. We could not confirm, however, that increase in entropy was due to cell activity. FTIR imaging allows more detailed investigation of early disc degeneration than traditional measures. There are no conflicts of interest. Partially funded by Dutch Arthritis Funds, personal grant KSE

Introduction. Herniated disc tissue removed at surgery is mostly nucleus pulposus, with varying proportions of annulus fibrosus, cartilage endplate, and bone. Herniated nucleus swells and loses proteoglycans, and herniated annulus is invaded by blood vessels and inflammatory cells. However, little is known about the significance of endplate cartilage and bone within a herniation. Methods. Herniated tissue was removed surgically from 21 patients (10 with sciatica, 11 without). 5-μm sections were examined using H&E, Toluidine blue, Giemsa, and Masson-trichrome stains. Each tissue type in each specimen was scored for tears/fissures, neovascularisation, proteoglycan loss, cell clustering, and inflammatory cell invasion. Proportions of each tissue type were quantified using image analysis software. Results. Herniations from patients with sciatica had greater nerve and blood vessel invasion (P<0.05), and a greater proportion contained cartilage endplate (7/10 vs 3/11, p<0.05). Cartilage fragments were generally small (5–20% of herniated mass) and showed little swelling or proteoglycan loss, or inflammatory cell invasion, although chondrocytes often formed small clusters. Most cartilage endplate fragments had a straight edge where it had been stripped from bone. Two cartilage fragments showed some bone still attached, and three showed small defects that were filled with nucleus tissue, bone, or endothelial cells. Conclusion. More than 50% of disc herniations contained cartilage endplate. The relatively stable nature of cartilage fragments may explain why they are less likely to resorb, and therefore more likely to cause persisting sciatica. Loss of cartilage will increase endplate permeability, increasing the risk of Modic changes, and disc infection

Introduction. Physical disruption of the extracellular matrix influences the mechanical and chemical environment of intervertebral disc cells. We hypothesise that this can explain degenerative changes such as focal proteoglycan loss, impaired cell-matrix binding, cell clustering, and increased activity of matrix-degrading enzymes. Methods. Disc tissue samples were removed surgically from 11 patients (aged 34–75 yrs) who had a painful but non-herniated disc. Each sample was divided into a pair of specimens (approximately 5mm. 3. ), which were cultured at 37°C under 5% CO. 2. One of each pair was allowed to swell, while the other was restrained by a perspex ring. Live-cell imaging was performed with a wide field microscope for 36 hrs. Specimens were then sectioned at 5 and 30 μm for histology and immunofluorescence using a confocal microscope. Antibodies were used to recognise free integrin receptor α5β1, matrix metalloprotease MMP-1, and denatured collagen types I-III. Proteoglycan content of the medium, analysed using the colorimetric DMMB assay, was used to assess tissue swelling and GAG loss. Constrained/unconstrained results were compared using matched-pair t-tests. Results. Time-lapse cinematography revealed small cell movements in unconstrained specimens, for up to 12 hrs. By 36 hrs, unconstrained (free swelling) samples showed greater: loss of GAG's (p<0.003), loss of integrin binding (p<0.02), synthesis of MMP-1 (p<0.03), and collagen denaturation (p<0.009). Cell clustering was evident in all tissues after 36 hrs. Conclusion. Swelling of disrupted disc tissue disturbs cell-matrix binding, increases matrix degradation, and allows increased proteoglycan loss. This sequence of events could follow disc injury or herniation in-vivo

Aims

This study aimed, through bioinformatics analysis and in vitro experiment validation, to identify the key extracellular proteins of intervertebral disc degeneration (IDD).

Background. Fissures in the anulus fibrosus are common in disc degeneration, and are associated with discogenic pain. We hypothesise that anulus fissures are conducive to the ingrowth of blood vessels and nerves. Purpose. To investigate the mechanical and chemical micro-environment of anulus fissures. Methods. Six thoracolumbar spine specimens, comprising three vertebrae and two discs, were obtained from cadavers aged 68-83 yr. Discs were injected with blue dye to reveal the location of complete anulus fissures. Each specimen was then subjected to 1000 N compression, while intradiscal compressive stress was investigated by pulling a miniature pressure transducer through the disc, in planes likely to cross the anulus fissures. Some additional disc fragments were removed at surgery from patients with discogenic back pain, and examined histologically to gauge the concentration of collagen and proteoglycans within radial fissures, using a qualitative method. Results. Stress profiles were obtained perpendicular to major anulus fissures in seven discs. A marked local reduction in vertically-acting compressive stress usually coincided with fissure location (confirmed at dissection), and stress reductions were inversely proportional to average pressure in the nucleus (r. 2. =0.56, p<0.05). Surgical disc samples showed local depletion of proteoglycans around the margins of radial and circumferential fissures, leaving a collagen-rich scaffold of the type known to support nerve and blood vessel growth. Conclusion. Compressive stresses within anulus fissures are reduced most when the disc nucleus is decompressed, because this facilitates internal displacements of disrupted tissue. Anulus fissures provide a micro-environment that is mechanically and chemically conducive to the ingrowth of blood vessels and nerves

Aims

Lumbar spinal stenosis (LSS) is a common skeletal system disease that has been partly attributed to genetic variation. However, the correlation between genetic variation and pathological changes in LSS is insufficient, and it is difficult to provide a reference for the early diagnosis and treatment of the disease.

This review provides a concise outline of the advances made in the care of patients and to the quality of life after a traumatic spinal cord injury (SCI) over the last century. Despite these improvements reversal of the neurological injury is not yet possible. Instead, current treatment is limited to providing symptomatic relief, avoiding secondary insults and preventing additional sequelae. However, with an ever-advancing technology and deeper understanding of the damaged spinal cord, this appears increasingly conceivable. A brief synopsis of the most prominent challenges facing both clinicians and research scientists in developing functional treatments for a progressively complex injury are presented. Moreover, the multiple mechanisms by which damage propagates many months after the original injury requires a multifaceted approach to ameliorate the human spinal cord. We discuss potential methods to protect the spinal cord from damage, and to manipulate the inherent inhibition of the spinal cord to regeneration and repair. Although acute and chronic SCI share common final pathways resulting in cell death and neurological deficits, the underlying putative mechanisms of chronic SCI and the treatments are not covered in this review.

Mesenchymal stem-cell based therapies have been proposed as novel treatments for intervertebral disc degeneration, a prevalent and disabling condition associated with back pain. The development of these treatment strategies, however, has been hindered by the incomplete understanding of the human nucleus pulposus phenotype and by an inaccurate interpretation and translation of animal to human research. This review summarises recent work characterising the nucleus pulposus phenotype in different animal models and in humans and integrates their findings with the anatomical and physiological differences between these species. Understanding this phenotype is paramount to guarantee that implanted cells restore the native functions of the intervertebral disc.

Cite this article: Bone Joint Res 2013;2:169–78.

This short contribution aims to explain how intervertebral disc ‘degeneration’ differs from normal ageing, and to suggest how mechanical loading and constitutional factors interact to cause disc degeneration and prolapse. We suggest that disagreement on these matters in medico-legal practice often arises from a misunderstanding of the nature of ‘soft-tissue injuries’.

This article reviews the current knowledge of the intervertebral disc (IVD) and its association with low back pain (LBP). The normal IVD is a largely avascular and aneural structure with a high water content, its nutrients mainly diffusing through the end plates. IVD degeneration occurs when its cells die or become dysfunctional, notably in an acidic environment. In the process of degeneration, the IVD becomes dehydrated and vascularised, and there is an ingrowth of nerves. Although not universally the case, the altered physiology of the IVD is believed to precede or be associated with many clinical symptoms or conditions including low back and/or lower limb pain, paraesthesia, spinal stenosis and disc herniation.

New treatment options have been developed in recent years. These include biological therapies and novel surgical techniques (such as total disc replacement), although many of these are still in their experimental phase. Central to developing further methods of treatment is the need for effective ways in which to assess patients and measure their outcomes. However, significant difficulties remain and it is therefore an appropriate time to be further investigating the scientific basis of and treatment of LBP.

The widespread use of MRI has revolutionised the diagnostic process for spinal disorders. A typical protocol for spinal MRI includes T1 and T2 weighted sequences in both axial and sagittal planes. While such an imaging protocol is appropriate to detect pathological processes in the vast majority of patients, a number of additional sequences and advanced techniques are emerging. The purpose of the article is to discuss both established techniques that are gaining popularity in the field of spinal imaging and to introduce some of the more novel ‘advanced’ MRI sequences with examples to highlight their potential uses.

Cite this article: Bone Joint J 2015;97-B:1683–92.