Aims

This study was performed to explore the effect of melatonin on pyroptosis in nucleus pulposus cells (NPCs) and the underlying mechanism of that effect.

Aims

Ageing-related incompetence becomes a major hurdle for the clinical translation of adult stem cells in the treatment of osteoarthritis (OA). This study aims to investigate the effect of stepwise preconditioning on cellular behaviours in human mesenchymal stem cells (hMSCs) from ageing patients, and to verify their therapeutic effect in an OA animal model.

Aims

The effect of the gut microbiota (GM) and its metabolite on bone health is termed the gut-bone axis. Multiple studies have elucidated the mechanisms but findings vary greatly. A systematic review was performed to analyze current animal models and explore the effect of GM on bone.

Introduction

Elastic fibres are constructed of a central core of elastin surrounded by microfibrils that are composed mainly of fibrillin-1 and fibrillin-2. Patients with mutations in the gene encoding fibrillin-1 or fibrillin-2 develop Marfan syndrome or Beals syndrome (congenital contractural arachnodactyly), respectively. Scoliosis is one of the clinical manifestations in these patients, but how a defect in the elastic proteins could lead to a spinal deformity is not clear. On the one hand, the mutations could induce scoliosis via mechanical means as they could lead to alterations in the biomechanics of the elastic fibre system. On the other hand, elastic fibres also bind growth factors such as transforming growth factor β (TGFβ) and bone morphogenic proteins (BMPs), and the mutations could hence change patterns of spinal growth.

The prosthesis anchored to the vertebral body by a large central keel has inherent risk of angular mismatching between vertebral endplate and prosthesis endplate at large lordotic segment such as L5-S1. Theoretically, these angular mismatching can be considered to cause several problems such as segmental hyperlordosis, anterior positioning of upper prosthesis, posterior prosthetic edge subsidence, decreased ROM and poor clinical outcome. The purpose of this study is to assess whether angular mismatching between vertebral endplate and prosthesis endplate in lumbar total disc replacement (L-TDR) with ProDisc-L influence on radiological and clinical outcomes.

We evaluated 64 levels of 56 patients who were implanted with ProDisc-L from 2002 to 2006. Prosthetic levels were 38 levels of L4–5, and 26 levels of L5-S1 (8 patients had 2 level-operations of L4–5 and L5-S1). Mean follow-up was 25.6 (12–49) months. Angle of mismatching between lower endplate of upper vertebral body and upper prosthetic plate, segmental flexion/extension ROM, segmental lordosis angle at extension, distance from the posterior wall of vertebral body to posterior prosthetic edge were measured in the radiographs. Clinically VAS and ODI were evaluated. Angular mismatching between upper vertebra and prosthesis of L4–5 and L5-S1 was 1.6° (range, 0–6°) and 5.6° (0–13°) (p< 0.001) respectively, at final follow-up. Angular mismatching at immediate postoperative radiographs (2.3° in L4–5 and 4.9° in L5-S1) and at final follow-up was not significantly different (p=0.324 in L4–5, 0.620 in L5-S1). Mean segmental ROM of operated levels was 10.6° (4–22°) in L4–5 and 6.1° (2–13°) in L5-S1(p< 0.001). Mean segmental ROM, mean segmental lordosis angle, and mean distance from posterior margin of vertebral body to posterior end of prosthesis in L5-S1 were 6.8° (4–13°), 12.8° (8–17°), 3.8mm (1–6mm) in cases with angular mismatching less than 10°, and 4.6° (2–7°), 21.3° (19–25°), 6.0 mm (2–8mm) in that of 10° or more (p=0.024, < 0.001, 0.039), respectively. In L4–5 angular mismatching of more than 5° were only 2 cases without statistical significance. Clinical outcomes, VAS and ODI, of L4–5 compared with that of L5-S1 and of angular mismatching less than 10° with that of 10° or more in L5-S1 did not have difference between them (p> 0.05). Angular mismatching between lower endplate of upper vertebra with upper prosthesis endplate is more common in L5-S1 than in L4–5. L-TDR at the most lordotic level, L5-S1, implantation of upper prosthesis with mismatched angle seems to be the causes of lessened segmental ROM, increased segmental lordosis, and anterior positioning of prosthesis.

Anterior decompression and fusion has been standard treatment for cervical disc herniation and myelopathy with disc degeneration. Since cervical total disc replacement (TDR) has been introduced with early favorable results and ideal mechanism, it has gained its popularity recently. But varying degrees of heterotopic ossification (HO) around the operated segment have been noted in the literatures. The theoretical advantages of TDR are the maintenance of intervertebral motion and prevention of adjacent segment degeneration. It is questionable that if HO occurs after TDR, mobility of operated segments would be restricted then clinical outcome worse. Purpose of this study is to determine prevalence of HO and to investigate that the presence of HO would limit motion and subsequently negatively affect clinical outcome following cervical TDR.

We analyzed 29 patients (30 levels) who were treated with cervical TDR by 2 spine specialists using 4 types of prostheses (Mobi-C: 13 levels, ProDisc: 10, Bryan: 5, Prestige LP: 2) consecutively from July 2004 to June 2007. Postoperative mean follow-up period was 21.4 (12–36) months. We assessed presence of HO and segmental ROM radiographically and clinical outcome by VAS, ODI after 1.5, 3, 6 months, and every year postoperatively in principle. All subjects were divided by 3, which were group A (no HO, McAfee class 0), group B (class I and II), and group C (class III and IV), then compared with each other.

HO was detected on 14 levels (46.7%) in the 30 levels after at mean of 8.2 (4–18) months after operation. There were 15 levels(53.3%) of group A (no HO, class 0), 7 levels of group B (class I HO:3, II: 4), and 7 levels of group C (class III: 3, IV: 4). Segmental flexion-extension ROM of group A was 10.1 (5.6–16.2)°, group B is 8.3 (3.5–14.4)°, and group C is 3.1 (0.0–6.6)° (p< 0.001, multiple comparison test with post hoc Bonferroni correction). And no difference in the clinical outcomes, VAS and ODI, was found compared with each other among group A, B, and C (p> 0.05).

Nonetheless, longer term follow-up should be performed to investigate whether clinical outcomes would be changed and occur adjacent level degeneration as time goes on. In addition, further study for prevention of HO may be needed as in HO of other joint replacement surgery not to lose superior mechanism to fusion treatment.

Intervertebral discs (IVDs) are fibrocartilagenous ovoids located between the vertebral bodies of the spine that provide the sole source of flexibility in that structure. IVDs are clinically very important as degeneration has been shown to be strongly associated with lower back pain, sciatica, and disc herniation: potentially disabling conditions that affect a very large section of the UK population.

The aetiology of disc degeneration is poorly understood although upregulation of matrix metalloproteinase (MMP) activity is thought to be involved. Degradation products of the extra-cellular matrix are known to increase MMP production and activity in other tissues. This project concentrated on examining the effects of degredation products of elastin. Elastin fragments (κ-elastin peptides) have been shown to upregulate mRNA levels and increase expression of pro-MMP-1 in human skin fibroblasts, cells that are thought to be similar to those residing in the annulus fibrosus of intervertebral discs. This study examined their effect on disc cells and on skin fibroblasts.

Total MMP-2 and -7 activity produced by cells extracted from the annulus fibrosus of bovine intervertebral disc cells and cultured for 24 hours with 0–300μg/ml κ-elastin was determined using fluorimetric and zymographic analyses. κ-elastin was prepared from bovine ligamentum nuchae or bovine intervertebral discs.

Culture with κ-elastin prepared from bovine ligamentum nuchae caused skin and disc cell potential pro-MMP-2 activity to increase in a dose-dependent manner; the potential pro-MMP-2 activity of both cell types is more than doubled when cultured with 300μg/ml κ-elastin.

These findings suggest that in the bovine disc, matrix breakdown may cause a feedback loop with degraded elastin stimulating disc cells to increase production of pro-MMP-2, with the possibility of further degrading elastin and other proteins and contributing to IVD breakdown.

Background: The intervertebral disc and spinal ligaments contain extensive and well organised elastic fibre networks which provide these tissues with elasticity. Morphologically elastic fibres are composed of an amorphous central core consisting mainly of elastin surrounded by a microfibrillar mesh. The importance of the microfibrils has been emphasised by the clinical manifestations of Marfan Syndrome (MFS) and congenital contractual arachnodactyly (CCA) which are caused respectively by mutations of Fibrillin-1 and Fibrillin-2, the main protein components of the microfibrillar mesh. Both patients of MFS and CCA can develop a spinal deformity. Recent studies on genetically modified mice suggested that minor components of the microfibrillar mesh can also play an important role in spine development; knockout mice containing no fibulin-5, microfibrillar associated glycoprotein-2 (MAGP-2), or latent TGF-b protein 3 (LTBP-3) can all develop spinal deformity. Our aim in this study was to understand the involvement of elastic fibre system in pathogenesis of scoliosis.

Methods: Tissue from Marfan patients and adolescent idiopathic kyphoscoliotic human intervertebral discs were removed during routine surgery with consent and ethical permission. Here we report on examination of disc tissue from three Marfan’s syndrome and three AIS patients (with ethical approval), age range 13–33 years. Tissues were dissected and then snap frozen within 4 hours after surgical excision and kept in −80 OC till used. Tissue sections of 20 micron were cut with a cryostat microtome and fixed with 10% formalin before immunostaining. Microfibrils and elastin fibre network were studied by immunostaining fibrillin-1 and elastin. The collagen network was examined by using fluores-cent microscopy with a polarised light system. Spines from transgenic mice, producing no elastin or fibulin-5, were paraffin embedded and sections were stained with Haematoxylin & Eosin or Alcien Blue. The morphology of cells, vertebral body and disc matrix were studied at light microscopic level.

Results and Discussion: Our histological studies on IVD tissues from MFS and AIS patients found that the elastic fibre and collagen networks were disorganised compared to that of normal controls. Studies on spines from fibulin-5 null or elastin null mice indicated delayed ossification of the vertebral body, lower expression of proteoglycans and an abnormal growth plate. Our initial results thus indicate that the elastic fibre system has an effect on matrix synthesis in connective tissue and plays a part in regulating bone growth. They are in agreement with reports that kypho-scoliosis occurs in transgenic mice deficient in other matrix components e.g. collagen-II and perlecan. Matrix-generated regulation of spine development and vertebral body growth thus appears to play an important role in the development of scoliosis.

Introduction: Elastin is a structural protein forming a highly organised network in the annulus and nucleus of the intervertebral disc (IVD). It appears important in maintaining annulus structure as it is densely located in the interlamellar space and forms cross-bridges between lamellae. Here we have investigated elastin fibre organisation in degenerate discs and compared it to that seen in normal human and bovine discs.

Methods: Human lumbar IVD were obtained from consented patients undergoing surgery either for disc degeneration, tumour or trauma. The disc segments were collected from operating theatre and graded. A radial profile of the specimen was dissected and snap-frozen. Sections of 20μm in thickness were cut with a cryostat microtome and mounted on slides. To visualize elastin fibres, sections were digested with hyaluronidase after fixation with 10% of formalin. Elastin fibres were immunostained and fibre organisation mapped.

Results: In degenerate disc, the elastin fibre network appeared sparse and disorganised in comparison to that seen in non-degenerate human or in bovine discs in which elastin fibres are well organised. In addition, in degenerate discs the elastin fibres appear fragmented. Fragmentation of the elastin network within lamellae of the annulus in particular increased with both degeneration grade and with age.

Discussion: The loss of elastic network integrity observed in degenerate discs could contribute to loss of annulus integrity and affect disc mechanical properties adversely. Furthermore, our initial results have suggested fragmented elastin degradation products could upregulate MMP expression by disc cells thus stimulating a degenerative cascade.

Background: The intervertebral disc has a highly organised collagen network (1) which has an important role in regulating the mechanical properties of the tissue. A recent study of bovine discs has also revealed an abundant and organised elastic fibre network (2) indicating that elastic fibres could play an important mechanical role. The aim of this study was to describe changes in organisation of the collagen and elastin fibre networks in scoliotic relative to normal discs.

Methods: Intact wedges of intervertebral disc were obtained from patients undergoing routine spinal surgery where the disc was removed by an anterior approach. Frozen sections were cut and examined as described in detail elsewhere (2). Briefly, they were digested with hyaluronidase to remove glycosaminoglycans. Micrographs of the sections were examined by polarised light to visualise collagen organisation. The elastic fibre network was visualised by histochemical staining with orcein or immunohistochemically. We examined 9 discs from 6 scoliotic patients (12–22y), ranging in level from T1 0/11 to L4/L5; three had adolescent idiopathic scoliosis and three neuromuscular scoliosis. We also examined 4 discs from a 12 year old female patient with a spinal tumour not affecting the discs, and 2 discs from a 17 year female patient who had discs removed as the result of trauma.

Results: The ‘control’ discs showed a highly organised collagen network arranged in regular lamellae as described previously (1). A highly organised elastic fibre network, similar to that described in bovine discs (2) was also revealed in the ‘control’ human discs. Dense elastic fibres were located between adjacent lamellae of the annulus. Elastic fibres appeared to be long (> 100μm) and straight in outer annulus and were at angle of approximately 600 or 1200 to those in adjacent lamellae in the inner annulus. Elastic fibre bridges crossing the lamellae perpendicularly or obliquely were observed. In scoliotic discs however, the organisation of the collagen network was grossly disturbed with marked loss of lamellar structure. Elastic fibres were very sparse and the elastic fibre networks were highly disorganised in all regions. Cell clusters, typical of disc degeneration, were seen in scoliotic but not in age-matched ‘control’ discs.

Conclusion: Our results reveal an abundant and organised network of elastic fibres in the young (12–17yr) human intervertebral disc. The localisation of these fibres in the inter-lamellar space suggests that the elastic fibre network plays a significant biomechanical role. This network is sparse and disrupted in scoliotic discs; loss of network integrity could affect disc biomechanical function adversely and could be involved in the progression of the spinal deformity.

Aim of the study: To evaluate whether additional aperture fixation to distal fixation (two-point fixation or 2P) may diminish tibial tunnel enlargement compared to distal fixation alone (one-point fixation or1P).

Methods: Two groups of patients were evaluated. In group 1P (44pts.) the grafts were fixed on the tibial side, using two 4 mm Mersilene tapes tied over a 10 mm bone bridge created in the anterior cortex. In group 2P, an additional fixation, using 1 absorbable cross pin in 27 pts. and 2 absorbable cross pins (Rigid fix, Mitek) in 24 pts., was performed. AP and lateral radiographs as well as patients evaluation were performed 3, 6 and 12 months post-op. Tibial tunnel size was measured at the widest diameter in both AP and lateral radiographs.

Results: Tunnel enlargement occurred in both groups at 3 months post-op, but not thereafter. In the lateral radiographs, tunnel enlargement was significantly less in group 2P compared to group 1P (p< 0.05). No statistical relationship was found between tunnel enlargement and gender, age, IKDC, and KT 1000 side-to-side difference.

Conclusion: Additional tibial graft fixation with cross-pins seems to diminish tibial tunnel enlargement in the sagital plane. This may be explained by the fact that the cross pins inserted in the coronal plane, reduce tibial graft movements mainly in the sagital plane. The study supports the hypothesis that tibial graft micro-movements during the period of tendon healing to bone (up to 3m) play a role in tibial tunnel enlargement after ACL reconstruction using hamstrings.