Aims. Adenosine, lidocaine, and Mg. 2+. (ALM) therapy exerts differential immuno-inflammatory responses in males and females early after anterior cruciate ligament (ACL) reconstruction (ACLR). Our aim was to investigate sex-specific effects of ALM therapy on joint tissue repair and recovery 28 days after surgery. Methods. Male (n = 21) and female (n = 21) adult Sprague-Dawley rats were randomly divided into ALM or Saline control treatment groups. Three days after ACL rupture, animals underwent ACLR. An ALM or saline intravenous infusion was commenced prior to skin incision, and continued for one hour. An intra-articular bolus of ALM or saline was also administered prior to skin closure. Animals were monitored to 28 days, and joint function, pain, inflammatory markers, histopathology, and tissue repair markers were assessed. Results. Despite comparable knee function, ALM-treated males had reduced systemic inflammation, synovial fluid angiogenic and pro-inflammatory mediators, synovitis, and fat pad fibrotic changes, compared to controls. Within the ACL graft, ALM-treated males had increased expression of tissue repair markers, decreased inflammation, increased collagen organization, and improved graft-bone healing. In contrast to males, females had no evidence of persistent systemic inflammation. Compared to controls, ALM-treated females had improved knee extension, gait biomechanics, and elevated synovial macrophage inflammatory protein-1 alpha (MIP-1α). Within the ACL graft, ALM-treated females had decreased inflammation, increased collagen organization, and improved graft-bone healing. In articular cartilage of ALM-treated animals, matrix metalloproteinase (MMP)-13 expression was blunted in males, while in females repair markers were increased. Conclusion. At 28 days, ALM therapy reduces inflammation, augments tissue repair patterns, and improves joint function in a sex-specific manner. The study supports transition to human safety trials. Cite this article: Bone Joint Res 2024;13(6):279–293

The pathophysiology of discogenic low back pain is poorly understood. The morphological changes occurring in disc degeneration are well documented but unhelpful in determining if a particular degenerate disc will be painful or not. Herniated intervertebral disc tisssue has been shown to produce a number of pro-inflammatory mediators and cytokines. No similar studies have to date been done utilising disc material from patients with discogenic low back pain. The aim of this study was to compare levels of production of interleukin-6 (IL-6), interleukin-8 (IL-8) and Prostaglandin E2 (PGE2) in disc tissue from patients undergoing discectomy for sciatica with that from patients undergoing fusion for discogenic low back pain. Tissue from 50 patients undergoing discectomy for sciatica and 20 patients undergoing fusion for discogenic low back pain was cultured and the medium harvested for subsequent analysis using an enzyme linked immunoabsorbent assay method. Statistical analysis of the results was performed using the Mann-Whitney test. Disc specimens from both experimental groups produced measurable levels of all three mediators. Mean production of IL-6, IL-8 and PGE2 in the sciatica group was 26.2±75.7, 247±573 and 2255±3974 respectively. Mean production of IL-6, IL-8 and PGE2 in the low back pain group was 92±154, 776±987 and 3221±3350 respectively (data = mean production pg/ml ± 1 standard deviation). There was a statistically significant difference between the levels of IL-6 and IL-8 production in the sciatica and low back pain groups (p< 0.006 and p< 0.003 respectively). The high levels of pro-inflammatory mediator production found in disc tissue from patients undergoing fusion for discogenic LBP may indicate that nucleus pulposis pro-inflammatory mediator production is a major factor in the genesis of a painful lumbar disc. This could explain why some degenerate discs cause LBP while other morphologically similar discs do not

Degenerate disc disease is a major cause of low back pain, yet its aetiology is still poorly understood. The intervertebral disc is the largest avascular structure in the body. Cells of the nucleus pulposus, therefore, rely on diffusion of oxygen & nutrients down concentration gradients from peripheral vessels in the cartilage end-plates. Thus, there is a low oxygen tension and cellular respiration is largely anaerobic. The purpose of this study was to examine the effects of inflammation, hypoxia and acidosis on degeneration and pro-inflammatory mediator production in virgin porcine nucleus pulposus cultures. Intervertebral discs were harvested from normal 6-month old agricultural pigs slaughtered for other purposes. Nucleus pulposus was contained within the annulus until further dissection under sterile conditions in the laboratory was performed. Nucleus pulposus was harvested, diced and divided into 200mg samples. Samples were incubated under optimal conditions. Discs were cultured in 5μg/ml E. coli lipopolysaccharide, in a hypoxic environment or at low pH. IL-6, IL-8 and LDH assays were performed by ELISA, in accordance with manufacturer’s instructions. Time and dose-response curves were generated for each experiment (results not shown). Results at 72 hours incubation are tabulated below:. These results confirm that nucleus pulposus is a biochemically active tissue capable of producing pro-inflammatory mediators in response to environmental stresses. IL-6 and IL-8 are both involved in the inflammatory cascade, causing chemotaxis of neutrophils and macrophages to the area. IL-8 itself causes hyperalgesia. Acidotic and inflammatory conditions, but not hypoxia, stimulated cytokine release. This may indicate a protective reduction in cellular activity in reduced oxygen environments. Necrosis, as measured by LDH production, was negligible

Introduction. Knee osteoarthritis (OA) is a major contributor to disability in seniors and affecting millions of people around the world. Its main problem and the biggest factor in the disability of patients is pain. Pain renders patient inactive and develops lower extremity muscle wasting and worsens patient status adversely. However no radical solution existed until now. Recently I discovered a very valid manipulative technique (Squeeze-hold) for OA knee. This study presents the one-year follow-up data (three cases) by this treatment. Methods. Subjects. The subjects were three severe knee OA patients who had their data collected for 12 months after having a treatment. Treatment (squeeze-hold): The lower limb muscles (all muscles attached to the knee joint) were squeezed and held by hand. Each squeeze was performed in linear sequence all the way through the lower limbs. The squeezes were held for 20 seconds. This treatment was performed on a weekly basis. Evaluation: The conditions of the OA were evaluated using a Kellgren-Lawrence Grading Scale. Visual analogue scale as indicator of pain and Japanese Knee Osteoarthritis Measure as indicator of the activity restriction were recorded every month for a year. Results. In all three cases, OA knee pain and ADL were gradually improved by sustained once-a-week treatment. The daily activities were gradually increased. After a year, the pain passed approximately away. In case 1 and 2, a limitation in ROM did not show a marked improvement and joint contracture remained. Discussion. Squeeze-hold therapy that is approach to lower-limb muscles relieved OA knee pain. It is suggested by the fact that lower-limb muscles is responsible for the pain. And the physical activity of knee OA patient increases with decreasing pain effected by Squeeze-hold therapy. This increase in physical activity provides increase in joint movement and it lead to improve articular metabolism. Cyclical loading increases chondrocyte activity. Additionally, It inhibits the release of matrix metalloproteinase, pro-inflammatory mediators and shear stress-induced nitric oxide that induces chondrocyte apoptosis. And further, this increased physical activity improves muscle-strengthening of the lower extremity. It is plausible that these effects may continuously lead to decreased pain and improved ADL. A primary pain in knee OA can be attributed to inflammation of knee joint capsule or within knee joint capsule. And the pain leads to muscular hypertonicity thereby a bigger secondary pain develops in the muscles. Decreased physical activity due to the pain worsens pathological condition to induce greater pain. By this means, there might be formed pain-deterioration chain. Squeeze-hold therapy reduces the myogenic pain and cut the pain-deterioration chain. However, ROM could not improve though the pain and ADL activity imploved. This treatment ought to be performed before the formation of articular contracture. The results indicate Squeeze-hold treatment for lower-limb muscles might improves OA knee pain and limited ADL. However, this study had only three cases. Further research efforts are needed to identify the adaptation to diverse clinical symptoms knee OA

Summary. Wear particles from joint replacements may result in loosening and periprosthetic osteolysis. Interference with systemic macrophage trafficking to the implant, modulation of macrophage phenotype from M1 to M2, and inhibition of NFκB may mitigate these adverse effects. Introduction. Joint replacement of the lower extremity is highly successful in alleviating pain, and improving ambulation and function. However, prosthetic byproducts of different materials, in sufficient amounts, may lead to loosening and periprosthetic osteolysis. Debris from polymers (such as polyethylene and PMMA), metals and ceramics are capable of inciting an adverse tissue reaction, which is orchestrated by cells of the monocyte/macrophage lineage. Three experimental approaches have been taken by our group to potentially mitigate the adverse biological sequela of particle disease. These include: 1) interfering with ongoing migration of monocyte/macrophages to the implant site by inhibiting the chemokine system 2) altering the functional activities of local macrophages by converting pro-inflammatory M1 macrophages to an anti-inflammatory pro-tissue healing M2 phenotype and 3) modulating the production and release of pro-inflammatory cytokines, chemokines and other potentially harmful factors by inhibiting the key transcription factor NFκB. Methods. First, a murine model of systemic trafficking of remotely infused macrophages to locally infused clinically relevant wear particles was established. After preliminary in vitro studies in which a key macrophage chemokine, MCP-1 was identified, blocking of this chemokine ligand-receptor axis using antagonists and knockouts was undertaken. Second, in vitro and in vivo studies were performed to convert M1 pro-inflammatory macrophages (associated with wear particles ± endotoxin) to an M2 alternative phenotype by the infusion of the anti-inflammatory cytokine Interleukin-4 (IL-4). Third, in vitro studies were undertaken in which activated macrophages were exposed to an NFκB decoy oligodeoxynucleotide (ODN), which interferes with the production of pro-inflammatory mediators. The analytical techniques used included bioluminescence, microCT, immunohistochemical and immunofluorescent microscopy, histomorphometry, ELISA, rT-PCR and cell sorting. Results. Interference of the MCP-1-CCR2 ligand-receptor axis decreased systemic macrophage migration to the area of particle infusion, and subsequent osteolysis at the implant site. Local delivery of IL-4 promoted an alternative anti-inflammatory M2 macrophage phenotype (rather than a pro-inflammatory M1 phenotype), mitigating inflammation and osteolysis. Preliminary studies exposing activated macrophages to NFκB ODN decreased pro-inflammatory cytokine production. Discussion/Conclusion. Macrophage-induced inflammation and osteolysis due to wear byproducts limit the longevity of joint replacements. The interventions outlined above may be useful in preventing these events. For example, coatings that limit macrophage migration to the implant site or local delivery of biologics that alter macrophage phenotype might facilitate osseointegration and provide a more robust bone-implant interface initially. Early osteolysis with a salvageable joint replacement might be mitigated by local infusion of IL-4 or an NFκB ODN. These treatments are less invasive compared to surgical revision, and might prolong the lifetime of a joint replacement in humans

Objective: It has been observed in previous studies of autologous blood transfusion in total knee arthroplasty, that this technique is associated with a lower infection rate, though studies have not been sufficiently large to demonstrate a significant difference. We hypothesised that autologous salvage blood contained high levels of pro-inflammatory mediators which may prime or augment the patients’ inflammatory response, and, in particular, the function of the polymorphonuclear leukocyte (PMN). Methods: Patients were randomised after consent to those receiving autologous transfusion and those having conventional treatment which was homologous transfusion only if clinically indicated. PMN were then isolated from the patients pre-admission immediately after the operation and 24 hours post-total knee arthroplasty. Three different aspects of PMN activity were measured: 1) The respiratory burst activity; 2) the ability to phagocytose microbes using radiolabelled staphylococcus epidermis; 3) and the ability to migrate across a collagen coated porous inserts. Results: 80 patients were studied, of whom 43 were in the autologous transfusion group and 37 in the first group. Of these 37, 6 had homologous transfusion. The study showed no significant difference between the phagocytic ability of the PMN from both groups. The main stimulus to transmigration is surgery itself. There was a significant increase in the production of reactive oxygen species by the PMN of those patients who received an autologous transfusion post-operatively. Conclusions: Using molecular biology techniques to study the PMN directly, our study indicates that autologous transfusion alters the activity of PMN and this indicates a possible mechanism whereby the immune response to infection could be enhanced. This, in turn, would explain the observed differences in infection rate in previous studies

Introduction: Patients with multiple skeletal injuries are susceptible to Systemic Inflammatory Response Syndrome (SIRS) and consequently Acute Respiratory Distress Syndrome (ARDS). Fracture haematoma contains pro-inflammatory mediators. The aim of our study was to show in vitro that fracture haematoma is implicated in neutrophil mediated injury, SIRS, ARDS and MOF. Methods: Fracture haematoma was isolated from 10 patients at the time of surgery. Neutrophils (PMN) were isolated from 10 healthy volunteers. PMN were exposed to the fracture haematoma supernatant and PMN activation in both primed and unprimed neutrophils were examined (CD11b and CD18 adhesion receptor expression and respiratory burst). PMN phagocytosis and apoptosis were also assessed using flow cytometry. Transmigration across an endothelial barrier was also measured following exposure to fracture haematoma. Results: Fracture haematoma had a marked effect on respiratory burst in primed PMNs (control = 100% vs 20% fracture haematoma = 1044% ± 405, p=0.04). CD11b and CD18 adhesion receptor expression were not upregulated in the fracture haematoma group. PMN phagocytosis of E coli was increased following treatment with fracture haematoma (control = 100% vs fracture haematoma = 171% ± 6SE, p=0.0001). Transendothelial migration of treated neutrophils was unaffected. Treatment of endothelial monolayers with fracture haematoma did not result in upregulated ICAM1 expression but was observed to induce significant endothelial cell death. PMN apoptosis was significantly delayed following exposure to fracture haematoma (control = 46% ± 5 vs fracture haematoma = 8% ±2, p=0.0005). Discussion: We have shown that fracture haematoma activates neutrophils, increases phagocytosis and respiratory burst whilst delaying apoptosis. These effects, whilst beneficial at the site of injury, may cause neutrophil mediated tissue injury systemically

Recently there has been considerable interest in the role of inflammatory mediator production by herniated degenerate discs. Modic has described MR endplate changes which have an inflammatory appearance and have been linked with discogenic back pain. To date there has been no biomechanical investigation of discs with associated Modic changes. The aim of this study is to determine if degenerate discs with associated Modic changes have higher levels of pro-inflammatory mediator production than those without Modic changes. Intervertebral disc tissue was obtained from 52 patients undergoing spinal surgery for sciatica [40] and discogram proven discogenic low back pain [12]. The tissue was cultured and the medium analysed for interleukin-6, interleukin-8 and prostaglandin E2 using an enzyme linked immunoabsorbetn assay method. Preoperative MR images of the patients were examined by a double blinded radiologist to determine the Modic status of the cultured disc level. Forty percent of patients undergoing surgery for discogenic low back pain had a Modic 1 change compared to only 12.5% of patients undergoing surgery for sciatica [p< .05] There was a statistically significant difference between levels of IL-6, IL-8 and PGE2 production by both the Modic1 [M1] and Modic2 [M2] groups compared to the Modic negative [NEG] group. IL-6:NEGvM1 p< .001, NEG v M2 p< .05, IL-8: NEG v M1 p< .01, NEG v M2 p> .05, PGE2: NEG v M1 p< 01, NEG v M2 p< .05. Modic changes have been associated with positive provocative discography by a number of authors. Pain generation requires the presence of nerves and hyperalgsia inducing mediators. Both IL-8 and PGE2 are known to induce hyperalgesia. The fact that Modic changes are associated with high levels of production of these mediators supports their role as an objective marker of discogenic low back pain

The role of nucleus pulposus (NP) biology in the genesis of sciatica is being increasingly investigated. The aim of this study was to examine the ability of control and degenerate human nucleus pulposus to respond to an exogenous pro-inflammatory stimulus. Control disc material was obtained from surgical procedures for scoliosis and degenerate disc tissue from surgical procedures for sciatica and low back pain. Disc specimens were cultured using a serumless technique under basal and lipopolysaccharride (LPS) stimulated conditions and the media harvested, aliquoted and stored at –80°C for subsequent analysis. Levels of IL-1β,TNFα, LTB4, GM-CSF, IL-6, IL-8, MCP-1, PGE2, bFGF and TGFβ-1 in the media were estimated using commercially available enzyme linked immunoabsorbent assay kits. Neither basal nor LPS stimulated control or degenerate NP produced detectable levels of IL-1β, TNFα, LTB4 or GM-CSF. Control disc IL-8 secretion increased significantly with LPS stimulation, p< .018. Degenerate disc IL-6, IL-8 and PGE2 production increased significantly with LPS stimulation, p< .01, p< .001 and p< .005 respectively. LPS stimulated degenerate NP secreted significantly more IL-6, IL-8 and PGE2 than LPS stimulated control NP, p < 0.05, 0.02 and 0.003 respectively. LPS induces an increase in both control and degenerate NP mediator production demonstrating the ability of human NP to react to a noxious stimulus by producing pro-inflammatory mediators. The difference in levels of basal and LPS stimulated mediator production between control and degenerate discs show that as a disc degenerates it increases both its level of inflammatory mediator production and its ability to react to a pro-inflammatory stimulus. The increased sensitivity of degenerating human NP to noxious stimuli and increased ability to respond with inflammatory mediator production support the role of NP as an active participant in the genesis of lumbar radiculopathy and discogenic back pain

Summary. The ideal therapy for post-traumatic osteoarthritis (PTOA) must be mechanism-based and target multiple anabolic and catabolic pathways. Our results suggest an innovative combination of known pro-anabolic and anti-catabolic biologics to treat post-traumatic cartilage degeneration. Introduction. Untreated joint injuries can result in cartilage wear and the development of PTOA. Previous studies identified the mechanisms that may govern the progression to PTOA. Here we hypothesised that targeted biologic interventions combined based on the type/time of cellular responses may constitute an effective novel treatment algorithm to arrest PTOA. Methods. Eleven human donor normal tali, age 19–71 yo, from the Gift of Hope Organ & Tissue Donor Network were impacted using a 4mm cylindrical indenter with the impulse of 1N as discribed. 8mm cartilage explants (4mm impacted core + 4mm non-impacted adjacent ring) were removed from the joint and cultured for 14 days in 5% fetal bovine serum with or without selected biologics. Treatment groups consisted of 1) Impacted control (IC), 2) Un-impacted control (UIC); 3–5) Impaction + three combinations of BMP-7/OP-1 (100ng/ml), P188 (8 ug/ml) and tumor necrosis factor-α (TNF-α) antagonist (100ng/ml) defined as Combo1, Combo2, and Combo3. All treatments were administered according to previously reported post-injury cellular responses. Combo1: P188 administered at day 0 for 48hrs + BMP-7 administered at day 0 for 48hrs and at days 7–14 + anti-TNF-α administered at days 0–7; Combo2: All three agents administered at day 0 for 48hrs and anti-TNF-α and BMP-7 administered again at day 7 for 48hrs; Combo3: All agents administered simultaneously at day 0 for 48hrs. Tissue and media were collected on days 0, 2, 7, and 14 and analyzed for cell viability, Safranin O staining, and proteoglycan (PG) synthesis. Results. A single impact to articular cartilage resulted in cell death within the superficial layer of impacted region, which if untreated, expanded to the adjacent non-impacted area. It reduced cell viability by more than 2-fold (p<0.01) and triggered elevation of pro-inflammatory mediators within the first 24–48 hrs and again around day 10. Initial anabolic responses characterised by the synthesis of superficial zone protein, endogenous BMP-7 and PGs were initiated at days 5–7. Cell survival in the superficial layer was improved under the individual or combined treatments with the most pronounced sustained effect under Combo1 & 2 (∼1.5-fold increase vs IC, p<0.05). Combo1 and to a lesser extend Combo 2 markedly improved cell survival in the entire cartilage thickness, which increased from 59% in IC to 84% in Combo1, p=0.006. Both Combo1 & 2 had a stronger effect on Safranin O staining and preservation of matrix integrity than Combo 3. Contrary, Combo3 exhibited the highest effect on PG synthesis (1.8-fold increase vs IC or other two combinations; p<0.05). Combo1 & 2 were less effective. Discussion. Current study reports two important findings: 1) the same combination of agents, but administered at various treatment regimens, can induce different effects. Prolonged administration of anti-TNF-α and BMP-7 (Combo1) had a strong effect on cell survival and matrix preservation, but was less effective in inducing chondrocyte synthetic activity suggesting that overstimulation/overdosing can have a detrimental effect on chondrocyte anabolism; 2) a window of opportunity exists to arrest cell death and delay/prevent cartilage degeneration

Aims

Mendelian randomization (MR) is considered to overcome the bias of observational studies, but there is no current meta-analysis of MR studies on rheumatoid arthritis (RA). The purpose of this study was to summarize the relationship between potential pathogenic factors and RA risk based on existing MR studies.

Aims

Post-traumatic osteoarthritis (PTOA) is a subset of osteoarthritis (OA). The gut microbiome is shown to be involved in OA. However, the effect of exercise on gut microbiome in PTOA remains elusive.

Aims

The anterior cruciate ligament (ACL) is known to have a poor wound healing capacity, whereas other ligaments outside of the knee joint capsule such as the medial collateral ligament (MCL) apparently heal more easily. Plasmin has been identified as a major component in the synovial fluid that varies among patients. The aim of this study was to test whether plasmin, a component of synovial fluid, could be a main factor responsible for the poor wound healing capacity of the ACL.

Objectives

Many in vitro studies have investigated the mechanism by which mechanical signals are transduced into biological signals that regulate bone homeostasis via periodontal ligament fibroblasts during orthodontic treatment, but the results have not been systematically reviewed. This review aims to do this, considering the parameters of various in vitro mechanical loading approaches and their effects on osteogenic and osteoclastogenic properties of periodontal ligament fibroblasts.

Objectives

Osteoarthritis (OA) is the most common form of arthritis, affecting approximately 15% of the human population. Recently, increased concentration of nitric oxide in serum and synovial fluid in patients with OA has been observed. However, the exact role of nitric oxide in the initiation of OA has not been elucidated. The aim of the present study was to investigate the role of nitric oxide in innate immune regulation during OA initiation in rats.