Objectives. Degenerative disc disease (DDD) and osteoarthritis (OA) are relatively frequent causes of disability amongst the elderly; they constitute serious socioeconomic costs and significantly impair quality of life. Previous studies to date have found that aggrecan variable number of tandem repeats (VNTR) contributes both to DDD and OA. However, current data are not consistent across studies. The purpose of this study was to evaluate systematically the relationship between aggrecan VNTR, and DDD and/or OA. Methods. This study used a highly sensitive search strategy to identify all published studies related to the relationship between aggrecan VNTR and both DDD and OA in multiple databases from January 1996 to December 2016. All identified studies were systematically evaluated using specific inclusion and exclusion criteria. Cochrane methodology was also applied to the results of this study. Results. The final selection of seven studies was comprehensively evaluated and includes results for 2928 alleles. The most frequent allele among all the studies was allele 27. After comparing the distributions of each allele with others, statistically significant differences have been found in the distribution of the alleles by the two groups, with an over-representation of allele (A)21 (disease: 3.22%, control: 0.44%). Thus, carrying A21 increased the risk of DDD. Such an association was not found to be statistically significant when considering the risk of OA. Conclusions. The findings suggest that VNTR A21 seems to be associated with higher risk to DDD, however, such an association may not be statistically significant regarding the risk of OA. Cite this article: L. Cong, G. Tu, D. Liang. A systematic review of the relationship between the distributions of aggrecan gene VNTR polymorphism and degenerative disc disease/osteoarthritis. Bone Joint Res 2018;7:308–317. DOI: 10.1302/2046-3758.74.BJR-2017-0207.R1

The World Health Organisation (WHO) has included low back pain in its list of twelve priority diseases. Notably, Degenerative disc disease (DDD) presents a large, unmet medical need which results in a disabling loss of mechanical function. Today, no efficient therapy is available. Chronic cases often receive surgery, which may lead to biomechanical problems and accelerated degeneration of adjacent segments. Our consortium partners have developed and studied mesenchymal stem cell-based, regenerative therapies trials. In previous phase 2 trial, patients exhibited rapid and progressive improvement of functional and pain indexes after 1 year with no significant side effects. To develop the world's first rigorously proven, effective treatment of DDD, EUROSPINE aims to assess, via a multicentre, randomized, controlled, phase 2b clinical trial including 112 patients with DDD, the efficacy of an allogenic intervertebral mesenchymal stem cell (MSC)-based therapy. This innovative therapy aims to rapidly and sustainably (at least 24 months) reduce pain and disability. In addition, the consortium aims to provide new knowledge on immune response & safety associated with allogeneic BM-MSC intradiscal injection. This simple procedure would be cost-effective, minimally invasive, and standardised. At the end of the RESPINE trial, we aim to propose a broadly available and clinically applicable treatment for DDD, marketed by European SMEs

We obtained intervertebral discs with cartilage endplates and underlying cancellous bone at operation from patients with degenerative disc disease and then used immunohistochemical techniques to localise the nerves and nerve endings in the specimens. We used antibodies for the ubiquitous neuronal protein gene product 9.5 (PGP 9.5). Immunoreactivity to neuropeptide Y was used to identify autonomic nerves and calcitonin gene-related peptide (CGRP) and substance P to identify sensory nerves. Blood vessels were identified by immunoreactivity with platelet-endothelial cell-adhesion molecule (CD31; PECAM). In a control group with no known history of chronic back pain, nerve fibres immunoreactive to PGP 9.5 and neuropeptide Y were most closely related to blood vessels, with occasional substance P and CGRP immunoreactivity. In patients with severe back pain and markedly reduced disc height, proliferation of blood vessels and accompanying nerve fibres was observed in the endplate region and underlying vertebral bodies. Many of these nerves were immunoreactive to substance P or CGRP, and in addition, substance P- and CGRP-immunoreactive nociceptors were seen unrelated to blood vessels. Quantification by image analysis showed a marked increase in CGRP-containing sensory nerve fibres compared with normal control subjects. We speculate that a chemotactic response to products of disc breakdown is responsible for the proliferation of vascularity and CGRP-containing sensory nerves found in the endplate region and vertebral body adjacent to degenerate discs. The neuropeptides substance P and CGRP have potent vasodilatory as well as pain-transmitting effects. The increase in sensory nerve endings suggests increase in blood flow, perhaps as an attempt to augment the nutrition of the degenerate disc. The increase in the density of sensory nerves, and the presence of endplate cartilage defects, strongly suggest that the endplates and vertebral bodies are sources of pain; this may explain the severe pain on movement experienced by some patients with degenerative disc disease

Degenerative disc disease, associated to low back pain, afflicts more than 50% of humans, and represents a major healthcare problem, especially for the pathology initiation. Current treatments range from conservative strategies to more invasive surgical techniques, such as disc removal and vertebral fusion. In the Intervertebral Disease (IVD) the nucleus pulposus (NP) degeneration is a key factor for the pathology initiation. Several tissue engineering approaches aiming to restore the appropriate NP cell (NPCs) and matrix content, were attempted by using adult stromal cells either from bone marrow or adipose tissue, chondrocytes, notochordal cells and more recently also pluripotent stem cells. However, none was fully satisfactory since the NP acid and a-vascularized environment appeared averse to the implanted heterologous cells. Several studies demonstrated the efficacy of platelet derivatives such as platelet rich plasma (PRP) in promoting the regeneration of connective tissues. We investigated the efficacy of PRP on NPCs proliferation and differentiation with the goal to propose the direct stimulation of resident cells (stimulation of endogenous cells – less invasive surgical procedure) or the implantation of NPCs expanded in vitro in the presence of PRP as therapeutic agents in IVD degeneration. NPCs were isolated from small fragments of NP explants, cultivated in medium supplemented with PRP or FCS (standard condition control) and characterized by FACS analysis for the expression of the typical mesenchymal stem cells markers CD34, CD44, CD45, CD73, CD90 and CD105. NPCs cultured in PL showed a phenotypic profile like the cells cultured in FCS. However, compared to NPCs expanded in the presence of FCS, NPCs expanded in PRP showed a much better proliferation and differentiation capacity. NPCs differentiation was evaluated by the cell ability to produce an organized metachromatic cartilaginous matrix, confirmed by the positive immunohistochemical staining for chondrogenic markers

Spinal surgery deals with the treatment of different pathological conditions of the spine such as tumors, deformities, degenerative disease, infections and traumas. Research in the field of vertebral surgery can be divided into two main areas: 1) research lines transversal to the different branches; 2) specific research lines for the different branches. The transversal lines of research are represented by strategies for the reduction of complications, by the development of minimally invasive surgical techniques, by the development of surgical navigation systems and by the development of increasingly reliable systems for the control of intra-operative monitoring. Instead, specific lines of research are developed within the different branches. In the field of oncological pathology, the current research concerns the development of in vitro models for the study of metastases and research for the study of targeted treatment methods such as electrochemotherapy and mesenchymal stem cells for the treatment of aneurysmal bone cysts. Research in the field of spinal deformities is focused on the development of increasingly minimally invasive methods and systems which, combined with appropriate pharmacological treatments, help reduce trauma, stress and post-operative pain. Scaffolds based on blood clots are also being developed to promote vertebral fusion, a fundamental requirement for improving the outcome of vertebral arthrodesis performed for the treatment of degenerative disc disease. To improve the management and the medical and surgical treatment of vertebral infections, research has focused on the definition of multidisciplinary strategies aimed at identifying the best possible treatment path. Thus, flow-charts have been created which allow to manage the patient suffering from vertebral infection. In addition, dedicated silver-coated surgical instrumentation and bone substitutes have been developed that simultaneously guarantee mechanical stability and reduce the risk of further local infection. In the field of vertebral traumatology, the most recent research studies have focused on the development of methods for the biostimulation of the bone growth in order to obtain, when possible, healing without surgery. Methods have also been developed that allow the minimally invasive percutaneous treatment of fractures by means of vertebral augmentation with PMMA, or more recently with the use of silicone which from a biomechanical point of view has an elastic modulus more similar to that of bone. It is clear that scientific research has changed clinical practice both in terms of medical and surgical management of patients with spinal pathologies. The results obtained stimulate the basic research to achieve even more. For this reason, new lines of research have been undertaken which, in the oncology field, aim at developing increasingly specific therapies against target receptors. Research efforts are also being multiplied to achieve regeneration of the degenerated intervertebral disc and to develop implants with characteristics increasingly similar to those of bone in order to improve mechanical stability and durability over time. Photodynamic therapies are being developed for the treatment of infections in order to reduce the use of antibiotic therapies. Finally, innovative lines of research are being launched to treat and regenerate damaged nerve structures with the goal, still far from today, of making patients with spinal cord injuries to walk

Mechanical failure of spine posterior fixation in the lumbar region Is suspected to occur more frequently when the sagittal balance is not properly restored. While failures at the proximal extremity have been studied in the literature, the lumbar distal junctional pathology has received less attention. The aim of this work was to investigate if the spinopelvic parameters, which characterize the sagittal balance, could predict the mechanical failure of the posterior fixation in the distal lumbar region. All the spine surgeries performed in 2017-2019 at Rizzoli Institute were retrospectively analysed to extract all cases of lumbar distal junctional pathology. All the revision surgeries performed due to the pedicle screws pull-out, or the breakage of rods or screws, or the vertebral fracture, or the degenerative disc disease, in the distal extremity, were included in the junctional (JUNCT) group. A total of 83 cases were identified as JUNCT group. All the 241 fixation surgeries which to date have not failed were included in the control (CONTROL) group. Clinical data were extracted from both groups, and the main spinopelvic parameters were assessed from sagittal standing preoperative (pre-op) and postoperative (post-op) radiographs with the software Surgimap (Nemaris). In particular, pelvic incidence (PI), sagittal vertical axis (SVA), pelvic tilt (PT), T1 pelvic angle (TPA), sacral slope (SS) and lumbar lordosis (LL) have been measured. In JUNCT, the main failure cause was the screws pull-out (45%). Spine fixation with 7 or more levels were the most common in JUNCT (52%) in contrast to CONTROL (14%). In CONTROL, PT, TPA, SS and PI-LL were inside the recommended ranges of good sagittal balance. For these parameters, statistically significant differences were observed between pre-op and post-op (p<0.0001, p=0.01, p<0.0001, p=0.004, respectively, Wilcoxon test). In JUNCT, the spinopelvic parameters were out of the ranges of the good sagittal balance and the worsening of the balance was confirmed by the increase in PT, TPA, SVA, PI-LL and by the decrease of LL (p=0.002, p=0.003, p<0.0001, p=0.001, p=0.001, respectively, paired t-test) before the revision surgery. TPA (p=0.003, Kolmogorov-Smirnov test) and SS (p=0.03, unpaired t-test) differed significantly in pre-op between JUNCT and CONTROL. In post-op, PI-LL was significantly different between JUNCT and CONTROL (p=0.04, unpaired t-test). The regression model of PT vs PI was significantly different between JUNCT and CONTROL in pre-op (p=0.01, Z-test). These results showed that failure is most common in long fused segments, likely due to long lever arms leading to implant failure. If the sagittal balance is not properly restored, after the surgery the balance is expected to worsen, eventually leading to failure: this effect was confirmed by the worsening of all the spinopelvic parameters before the revision surgery in JUNCT. Conversely, a good sagittal balance seems to avoid a revision surgery, as it is visible is CONTROL. The mismatch PI-LL after the fixation seems to confirm a good sagittal balance and predict a good correction. The linear regression of PT vs PI suggests that the spine deformity and pelvic conformation could be a predictor for the failure after a fixation

Although success has been achieved with implantation of bone marrow mesenchymal stem cells (bMSCs) in degenerative discs, its full potential may not be achieved if the harsh environment of the degenerative disc remains. Axial distraction has been shown to increase hydration and nutrition. Combining both therapies may have a synergistic effect in reversing degenerative disc disease. In order to evaluate the effect of bMSC implantation, axial distraction and combination therapy in stimulating regeneration and retarding degeneration in degenerative discs, we first induced disc degeneration by axial loading in a rabbit model. The rabbits in the intervention groups performed better with respect to disc height, morphological grading, histological scoring and average dead cell count. The groups with distraction performed better than those without on all criteria except the average dead cell count. Our findings suggest that bMSC implantation and distraction stimulate regenerative changes in degenerative discs in a rabbit model

Discogenic low back pain affects 42% of patients suffering low back pain. Degenerative disc disease is described as failure in cellular response to external stresses leading to physiologic dysfunction. Glycosylation patterns of tissues give insights into the spatially and temporally regulated inflammatory and degenerative processes. These glycoconjugates participate in many key biological processes including molecular trafficking and clearance, receptor activation, signal transduction, and immunomodulation. We hypothesise that glycoprofile of the the intervertebral disc(IVD) is temporally and spatially distinct in health and degeneration. The glycoprofile of the IVD has been studied in murine, bovine and ovine models for injury and aging. In this study, healthy(n=2) and degenerated(n=2) human IVD samples received from Utrecht(UU, ND) with ethical approval(NUIG), were compared using lectin histochemistry. The N-glycan profile of human degenerated IVD samples was characterised by high resolution quantitative UPLC-MS. Healthy and degenerated human discs present distinct glycosylation trends intracellularly/extracellularly in annulus fibrosus(AF) and nucleus pulposus(NP) tissue. There are quantitative and spatial differences in glycosylation in healthy and degenerated tissue. These findings are consistent with previous studies of IVD in murine, bovine and ovine models. The human N-glycan profile of degenerated surgical tissues is distinct from other cited tissue profiles such as human plasma. 5. These studies offer validation of previous animal models of IVD injury and degeneration, demonstrating similar changes in the glycoprofile in both animals and humans. Glycoprofiling may offer insight into disease progression, offering new realms of disease classification in patient specific manner while also elucidating potentials therapeutic targets, inhibiting disease progression

Early clinical studies investigating the effects of delivery of mesenchymal stromal cells (MSCs) to degenerated intervertebral discs have shown promising results, but with an incomplete understanding of the therapeutic mechanism(s) of action. To address this, we have developed a 3D co-culture system to unravel the biological interaction between MSCs and nucleus pulposus (NP) cells. Alginate constructs were created using a biphasic configuration consisting of a cylindrical shell with an encapsulated bead. Human NP cells were seeded in monolayer or encapsulated within alginate and cultured in hypoxia with variations of pH, osmolarity and growth factors (n = 6) to replicate healthy or degenerative conditions. Wells and gels were fixed and stained for ECM content, and retrieved cells and media were analysed for ECM and inflammatory factor expression. Encapsulated hNPCs showed no migration from either alginate structure and full bead separation was achieved over 14 days, reinforcing the construct as a separable 3D co-culture method. Addition of the degenerative growth factors TNFα and IL-1β as well as the adjustment of media pH to degenerative levels (pH 6.8) caused the hNPCs to decrease in size and proliferate significantly higher than control levels. TGF-β3 addition showed higher incidence of aggrecan deposition over addition of IL-1β. Addition of FGF2 altered cell morphology and ECM deposition including formation of pseudo lamellae, indicating a phenotype shift toward annulus fibrosis cells as shown in late-stage degenerative disc disease. The data from this study will be used in future MSC:NPC co-cultures to determine immunoregulatory interactions in a degenerative environment

Background. Proteoglycans (PGs) have long been known to be important to the functioning of the intervertebral disc. The most common PG is aggrecan, but there are also small leucine-rich proteoglycans (SLRPs) which constitute only a small percentage of the total PGs. However, they have many important functions, including organising the collagen, protecting it from degradation and attracting growth factors to the disc. We have examined how the core proteins of these molecules vary in intervertebral discs from patients with different pathologies. Methods. Discs were obtained from patients with scoliosis (n=7, 19–53y), degenerative disc disease (DDD) (n=6, 35–51y) and herniations (n=5, 33–58y). Proteoglycans were extracted and the SLRPs (biglycan, decorin, fibromodulin, keratocan and lumican) were characterised via Western blotting following enzymatic digestion with chondroitinase ABC and keratanase. Results. At least some SLRPs were present in all the discs studied. In addition to the presence of intact SLRP core proteins there was evidence of fragmentation of all the core proteins but especially of biglycan, fibromodulin and keratocan. Biglycan and keratocan were present in the majority of samples with biglycan being highly fragmented in the majority and keratocan usually present as 2 molecular weight bands. Fibromodulin was present in all samples except for 1 scoliotic disc and usually showed a high degree of fragmentation. The intact core protein of lumican was detected in all samples and was only present as a fragment in one of the older scoliosis samples. Decorin was present in a few samples of which half showed fragmentation. Conclusion. Although the number of samples investigated so far is low, fragmentation of these SLRP molecules appears common in the pathological intervertebral disc. These findings are useful not only in helping unravel pathways of disc degeneration, but may also provide early biomarkers of the different pathologies. Conflicts of Interest. None. Source of Funding. None. Acknowledgements: MRC and AR UK for financial support of SR & SO

Background. Nerve Root compression can lead to severe back pain. Different risk factors like high BMI, smoking, alcohol and psychological history have been identified. The aim of our study was to identify if the incidence of these risk factors was higher in patients with nerve root compression. Patients and methods. We collected data prospectively for 26 consecutive patients admitted between January and March 2011 with severe back pain and had an MRI scan. Demographic details were recorded along with occupation, BMI, smoking status, alcohol intake and psychological history. 12 patients had nerve root compression (Group A) on MRI scan and 14 had normal MRI scan (Group B). Results. The mean age for Group A was 46 years (range-35–67). 6 (50%) were female and 6 male. 2 patients had degenerative disc disease (DDD), 2 had simple falls, and one had tumour. 5 (42%) were employed, 2 (17%) unemployed and 2 (17%) housewives. The mean BMI was 26 (range-14–34). 4 patients (33%) were smokers and 5 were (42%) alcohol users. 2 patients (17%) had associated psychological history of depression. The mean age for Group B was 49 years (range-23–79). 12 (86%)were female and 2(14%)male. 2 had DDD and 1 had trauma. 6(43%)were employed, 2 (14%) unemployed and 3 (21%) housewives. The mean BMI was 25 (range-20–40). 9 patients (64%) were smokers and 9 enjoyed alcohol. 5 patients (36%) had associated psychological history; 3 of anxiety and 2 of depression. Conclusions. More females(86%)were admitted with severe back pain and normal MRI scan and had higher incidence of psychological history(36%), smoking and alcohol problems(64%)as compared to patients with nerve root compression. There was no difference in the mean age, occupation status, predisposing risk factors and BMI in both groups. Females with severe back pain should be routinely assessed for associated psychological history, smoking and alcohol problems before arranging MRI scan and appropriate advice on treatment should be given. Conflicts of Interest. None. Source of Funding. None

Summary Statement. To evaluate carbon-fiber-reinforced PEEK as alternative biomaterial for total disc arthroplasty a closed loop between biotribology (in vitro), application of sterile particle suspensions in the epidural space of rabbits and biological response in vivo was established. Introduction. To prevent adjacent level degeneration in the cervical spine, total disc arthroplasty (TDA-C) remains an interesting surgical procedure for degenerative disc disease. Short- or midterm complications are migration, impaired post-operative neurological assessment due to artefacts in x-ray and MRI diagnosis and substantial rates of heterotopic ossification. The idea was to create a TDA-C design based on a polymer-on-polymer articulation to overcome these limitations of the clinically established metal-on-polyethylene designs. The objective of our study was to characterise the biotribological behaviour of an experimental cervical disc replacement made out of carbon-fiber-reinforced (CFR) PEEK and evaluate the biological response of particulate wear debris in the epidural space in vivo. Materials & Methods. In vitro wear simulation acc. to ISO 18192-1 was performed for 10 million cycles on a clinically established TDA-C device (Aesculap, Tuttlingen) made of cobalt-chromium-on-polyethylene in a direct comparison to an experimental disc prototype made of CFR-PEEK. An estimation of particle size and morphology was done acc. to Affatato et al. [5] and sterile suspensions of comparable particles (size 90% < 1 µm) in phospate buffered saline (PBS) were produced [6] for the application in the epidural space of 36 white new zealand rabbits. The particle concentration was 1 mg/ml with a volume of 0.2 ml injected percutaneously using fluoroscopic guidance and the inflammatory response was assessed 3 and 6 months post-operatively in a direct comparison between the groups PBS (control), UHMWPE and CFR-PEEK. Results. The gravimetric wear rate was for the cobalt-chromium-on-polyethylene TDA-C device as a clinical reference 1.0 ± 0.1 mg/ million cycles, compared to 0.02 ± 0.02 mg/ million cycles for the experimental CFR-PEEK articulation (p < 0.001), whereas the cumulative amount of wear of the CFR-PEEK TDA-C prototypes (0.5 ± 0.23 mg/ million cycles) was decreased by an order of a magnitude compared to cobalt-chromium-on-polyethylene (12.1 ± 1.46 mg/ million cycles) (p < 0.001). For CFR-PEEK and UHMWPE most of the particles were observed in a submicron size range and the morphology was comparable. Histopathological examination demonstrated wear debris in the vertebral canal of injection sites surrounded by inflammatory cells. The inflammation was limited to the epidural space around the particles and polymer particles were associated by a low grade foreign body reaction comprising macrophages and multi-nucleated giant cells. CFR-PEEK particulate wear debris showed at least similar histopathological reactions than UHMWPE in the cervical epidural space. Conclusion. A closed loop between biotribology (in vitro), application of sterile particle suspensions in the epidural space of rabbits and biological response in vivo was established to evaluate carbon-fiber-reinforced PEEK as alternative biomaterial for total disc arthroplasty

Objectives

Interleukin 18 (IL-18) is a regulatory cytokine that degrades the disc matrix. Bone morphogenetic protein-2 (BMP-2) stimulates synthesis of the disc extracellular matrix. However, the combined effects of BMP-2 and IL-18 on human intervertebral disc degeneration have not previously been reported. The aim of this study was to investigate the effects of the anabolic cytokine BMP-2 and the catabolic cytokine IL-18 on human nucleus pulposus (NP) and annulus fibrosus (AF) cells and, therefore, to identify potential therapeutic and clinical benefits of recombinant human (rh)BMP-2 in intervertebral disc degeneration.

In a study on ten fresh human cadavers we examined the change in the height of the intervertebral disc space, the angle of lordosis and the geometry of the facet joints after insertion of intervertebral total disc replacements. SB III Charité prostheses were inserted at L3-4, L4-5, and L5-S1. The changes studied were measured using computer navigation sofware applied to CT scans before and after instrumentation.

After disc replacement the mean lumbar disc height was doubled (p < 0.001). The mean angle of lordosis and the facet joint space increased by a statistically significant extent (p < 0.005 and p = 0.006, respectively). By contrast, the mean facet joint overlap was significantly reduced (p < 0.001). Our study indicates that the increase in the intervertebral disc height after disc replacement changes the geometry at the facet joints. This may have clinical relevance.