Anti-Interleukin-6 Therapy Decreases Hip Synovitis and Bone Resorption and Increases Bone Formation Following Ischemic Osteonecrosis of the Femoral Head

Legg-Calvé-Perthes disease (LCPD) is a juvenile form of ischemic femoral head osteonecrosis, which produces chronic hip synovitis, permanent femoral head deformity, and premature osteoarthritis. Currently, there is no medical therapy for LCPD. Interleukin-6 (IL-6) is significantly elevated in the synovial fluid of patients with LCPD. We hypothesize that IL-6 elevation promotes chronic hip synovitis and impairs bone healing after ischemic osteonecrosis. We set out to test if anti-IL-6 therapy using tocilizumab can decrease hip synovitis and improve bone healing in the piglet model of LCPD. Fourteen piglets were surgically induced with ischemic osteonecrosis and assigned to two groups: the no treatment group (n = 7) and the tocilizumab group (15 to 20 mg/kg, biweekly intravenous injection, n = 7). All animals were euthanized 8 weeks after the induction of osteonecrosis. Hip synovium and femoral heads were assessed for hip synovitis and bone healing using histology, micro-CT, and histomorphometry. The mean hip synovitis score and the number of synovial macrophages and vessels were significantly lower in the tocilizumab group compared with the no treatment group (p < .0001, p = .01, and p < .01, respectively). Micro-CT analysis of the femoral heads showed a significantly higher bone volume in the tocilizumab group compared with the no treatment group (p = .02). The histologic assessment revealed a significantly lower number of osteoclasts per bone surface (p < .001) in the tocilizumab group compared with the no treatment group. Moreover, fluorochrome labeling showed a significantly higher percent of mineralizing bone surface (p < .01), bone formation rate per bone surface (p < .01), and mineral apposition rate (p = .04) in the tocilizumab group. Taken together, tocilizumab therapy decreased hip synovitis and osteoclastic bone resorption and increased new bone formation after ischemic osteonecrosis. This study provides preclinical evidence that tocilizumab decreases synovitis and improves bone healing in a large animal model of LCPD. © 2020 American Society for Bone and Mineral Research (ASBMR).     

Interleukin‐6 and Tumour Necrosis Factor in Synovial Fluid from Horses with Carpal Joint Pathology

The carpal joints are common sites of traumatic arthritis and osteoarthritis (OA) in athletic horses. The pro‐inflammatory cytokines interleukin (IL)‐6 and tumour necrosis factor (TNF) may be of great importance in the development of intra‐articular lesions. The aim of the present study was to investigate possible associations between synovial fluid levels of bioactive IL‐6 and TNF and different types of joint lesions seen in traumatic arthritis and OA. Synovial fluid was collected from horses with carpal lameness immediately before arthroscopic surgery. Articular cartilage, synovial membranes and intra‐articular ligaments were assessed macroscopically at arthroscopy. Synovial fluid levels of IL‐6 and TNF were determined by bioassays, and the cytokine levels between different grades of morphologic changes in each type of assessed tissue were compared. The highest levels of IL‐6 were detected in joints with chip fractures. All joints with chip fractures also showed some degree of synovitis. Tumour necrosis factor bioactivity was low and not associated with any joint lesion. Hence, TNF is not useful as a biomarker indicating a specific joint lesion in equine traumatic arthritis or OA. We conclude that a dramatic increase of IL‐6 in synovial fluid indicates the presence of osteochondral fragmentation, although low or undetectable levels of IL‐6 do not exclude chip fractures. The role of IL‐6 in the disease process of osteochondral fragmentation needs further investigation.     

Autologous protein solution prepared from the blood of osteoarthritic patients contains an enhanced profile of anti‐inflammatory cytokines and anabolic growth factors

The objective of this clinical study was to test if blood from osteoarthritis (OA) patients (n = 105) could be processed by a device system to form an autologous protein solution (APS) with preferentially increased concentrations of anti‐inflammatory cytokines compared to inflammatory cytokines. To address this objective, APS was prepared from patients exhibiting radiographic evidence of knee OA. Patient metrics were collected including: demographic information, medical history, medication records, and Knee Injury and Osteoarthritis Outcome Score (KOOS) surveys. Cytokine and growth factor concentrations in whole blood and APS were measured using enzyme‐linked immunosorbent assays. Statistical analyses were used to identify relationships between OA patient metrics and cytokines. The results of this study indicated that anti‐inflammatory cytokines were preferentially increased compared to inflammatory cytokines in APS from 98% of OA patients. APS contained high concentrations of anti‐inflammatory proteins including 39,000 ± 20,000 pg/ml IL‐1ra, 21,000 ± 5,000 pg/ml sIL‐1RII, 2,100 ± 570 pg/ml sTNF‐RI, and 4,200 ± 1,500 pg/ml sTNF‐RII. Analysis of the 82 patient metrics indicated that no single patient metric was strongly correlated (R² > 0.7) with the key cytokine concentrations in APS. Therefore, APS can be prepared from a broad range of OA patients. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1349–1355, 2014.     

Pentoxifylline improves haemoglobin and interleukin‐6 levels in chronic kidney disease

Aim: To assess whether pentoxifylline improves anaemia of chronic kidney disease (CKD) via suppression of interleukin‐6 (IL‐6) and improved iron mobilization. Background: CKD patients may have elevated IL‐6 and tumour necrosis factor alpha levels. These cytokines can increase hepcidin production, which in turn reduces iron release from macrophages resulting in reduced availability of iron for erythropoiesis. In experimental models, pentoxifylline was shown to reduce IL‐6 expression. Methods: We studied 14 patients with stages 4–5 CKD (glomerular filtration rate <30mL/min per 1.73 m²) due to non‐inflammatory renal diseases. None of the patients had received immunosuppressive or erythropoietin‐stimulating agents or parenteral iron. Patients had weekly blood tests for iron studies and cytokines during a control run‐in period of 3 weeks and during 4 weeks of pentoxifylline treatment. Results: Ten patients (eGFR 23 ± 6 mL/min) completed the study. At the end of the run‐in period average haemoglobin was 111 ± 5 g/L, ferritin 92 ± 26 µg/L, transferrin saturation 15 ± 3% and circulating IL‐6 10.6 ± 3.8 pg/mL. Tumour necrosis factor alpha values were below threshold for detection. Treatment with pentoxifylline reduced circulating IL‐6 (6.6 ± 1.6 pg/mL, P < 0.01), increased transferrin saturation (20 ± 5%, P < 0.003) and decreased serum ferritin (81 ± 25 µg/L, P = NS). Haemoglobin increased after the second week of pentoxifylline, reaching 123 ± 6 g/L by week 4 (P < 0.001). Conclusions: Pentoxifylline reduces circulating IL‐6 and improves haemoglobin in non‐inflammatory moderate to severe CKD. These changes are associated with changes in circulating transferrin saturation and ferritin, suggesting improved iron release. It is hypothesized that pentoxifylline improves iron disposition possibly through modulation of hepcidin.     

Effect of pro‐inflammatory and immunoregulatory cytokines on human tenocytes

Tendon injury induces a local inflammatory response, characterized by the induction of pro‐inflammatory cytokines. The aim of the present study was to analyze the effects of TNFα, IL‐6 and IL‐10 on key parameters of tendon homeostasis. Cultured primary human tenocytes were treated with the recombinant cytokines IL‐6, IL‐10, TNFα, or combinations of TNFα with IL‐6 and IL‐10 (10 ng/mL, 6, 24 h). Expression of type I collagen, elastin, MMP‐1, TNFα, IL‐1β, IL‐6, IL‐10, and suppressors of cytokine signaling (SOCS1, 3) was analyzed with the use of RTD‐PCR, immunocytochemistry, and Western blot analysis. In response to TNFα, tenocytes reduced their type I collagen deposition but increased their elastin gene expression and highly upregulated their expression for MMP‐1, pro‐inflammatory (TNFα, IL‐1β) and immunoregulatory (IL‐6, IL‐10) cytokines. TNFα stimulation augmented SOCS1, whereas SOCS3 expression in tenocytes was also induced by IL‐6. The treatment of tenocytes with IL‐6 and IL‐10 had no effect on cytokine expression. Neither IL‐6 nor IL‐10 modulated the observed effects of TNFα significantly. These results indicate that TNFα strongly activates the tenocytes to amplify their own TNFα expression and, subsequently, that of other regulatory cytokines and matrix degrading enzymes. However, the impact of IL‐6 and IL‐10 on tenocytes remains unclear. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1071–1077, 2010     

Role of hemorrhage in the induction of systemic inflammation and remote organ damage: Analysis of combined pseudo‐fracture and hemorrhagic shock

This study was performed to analyze the role of hemorrhage‐induced hypotension in the induction of systemic inflammation and remote organ dysfunction. Male C57/BL6 mice (6‐ to 10‐week old and 20–30 g) were used. Animals were either subjected to pseudo‐fracture [PF; standardized soft‐tissue injury and injection of crushed bone, PF group: n = 9], or PF combined with hemorrhagic shock (HS + PF group: n = 6). Endpoint was 6 h. Systemic inflammation was assessed by IL‐6 and IL‐10 levels. Myeloperoxidase (MPO) and NF‐κB activity in the lung and liver tissue were obtained to assess remote organ damage. The increases of systemic cytokines are similar for animals subjected to PF and PF + HS (IL‐6: 189 pg/ml ± 32.5 vs. 160 pg/ml ± 5.3; IL‐10: 60.3 pg/ml ± 15.8 vs. 88 pg/ml ± 32.4). Furthermore, the features (ALT; NF‐κB) of liver injury are equally elevated in mice subjected to PF (76.9 U/L ± 4.5) and HS + PF (80 U/L ± 5.5). Lung injury, addressed by MPO activity was more severe in group HS + PF (2.95 ng/ml ± 0.32) than in group PF (1.21 ng/ml ± 0.2). Both PF and additional HS cause a systemic inflammatory response. In addition, hemorrhage seems to be associated with remote affects on the lung. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:270–274, 2011     

Differential Effector Response of Amnion‐ and Adipose‐Derived Mesenchymal Stem Cells to Inflammation; Implications for Intradiscal Therapy

Intervertebral disc degeneration (IVDD) is a progressive condition marked by tissue destruction and inflammation. The therapeutic effector functions of mesenchymal stem cells (MSCs) makes them an attractive therapy for patients with IVDD. While several sources of MSCs exist, the optimal choice for use in the inflamed IVD remains a significant question. Adipose (AD)‐ and amnion (AM)‐derived MSCs have several advantages compared with other sources, however, no study has directly compared the impact of IVDD inflammation on their effector functions. Human MSCs were cultured in media with or without supplementation of interleukin‐1β (IL‐1β) and tumor necrosis factor‐α at concentrations reportedly produced by IVDD cells. MSC proliferation and production of pro‐ and anti‐inflammatory cytokines were quantified following 24 and 48 h of culture. Additionally, the osteogenic and chondrogenic potential of AD‐ and AM‐MSCs was characterized via histology and biochemical analysis following 28 days of culture. In inflammatory culture, AM‐MSCs produced significantly more anti‐inflammatory IL‐10 (14.47 ± 2.39 pg/ml; p = 0.004) and larger chondrogenic pellets (5.67 ± 0.26 mm²; p = 0.04) with greater percent area staining positively for glycosaminoglycan (82.03 ± 3.26%; p < 0.001) compared with AD‐MSCs (0.00 ± 0.00 pg/ml; 2.76 ± 0.18 mm²; 34.75 ± 2.49%; respectively). Conversely, AD‐MSCs proliferated more resulting in higher cell numbers (221,000 ± 8,021 cells; p = 0.048) and produced higher concentrations of pro‐inflammatory cytokines prostaglandin E₂ (1,118.30 ± 115.56 pg/ml; p = 0.030) and IL‐1β (185.40 ± 7.63 pg/ml; p = 0.010) compared with AM‐MSCs (109,667 ± 5,696 cells; 1,291.40 ± 78.47 pg/ml; 144.10 ± 4.57 pg/ml; respectively). AD‐MSCs produced more mineralized extracellular matrix (3.34 ± 0.05 relative absorbance units [RAU]; p < 0.001) compared with AM‐MSCs (1.08 ± 0.06 RAU). Under identical inflammatory conditions, a different effector response was observed with AM‐MSCs producing more anti‐inflammatories and demonstrating enhanced chondrogenesis compared with AD‐MSCs, which produced more pro‐inflammatory cytokines and demonstrated enhanced osteogenesis. These findings may begin to help inform researchers which MSC source may be optimal for IVD regeneration. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2445–2456, 2019     

IL‐6 and IL‐10 in post‐transplant lymphoproliferative disorders development and maintenance: a longitudinal study of cytokine plasma levels and T‐cell subsets in 38 patients undergoing treatment

IL‐6 and IL‐10 have previously been implicated in the pathogenesis of post‐transplant lymphoproliferative disorders (PTLD) and, like peripheral lymphocyte populations, are markers of immune status that are amenable to study in vivo. Thus, we analyzed cytokine plasma levels as well as lymphocyte subsets in a longitudinal analysis of 38 adult transplant recipients undergoing treatment for PTLD. Pretherapeutically, we found significantly elevated IL‐6 (13.8 pg/ml) and IL‐10 plasma levels (54.7 pg/ml) – in the case of IL‐10, even higher in treatment nonresponders than in responders (116 vs. 14 pg/ml). Over time, however, IL‐10 levels did not correlate with the course of disease, whereas those of IL‐6 did, falling in responders and rising in nonresponders. These findings were independent of histological EBV‐status, treatment type, and total peripheral T‐cell counts, which were significantly reduced in patients with PTLD. Our observations support the idea that although IL‐10 is important for creating a permissive environment for post‐transplant lymphoma development, IL‐6 is associated with PTLD proliferation. The analysis of lymphocyte subsets further identified HLA‐DR+ CD8+ lymphocyte numbers as significantly different in non‐PTLD controls (33%), treatment responders (44%) and nonresponders (70%). Although the specificity of these cells is unclear, their increase might correlate with the impaired tumor‐specific cytotoxic‐T‐lymphocyte (CTL)‐response in PTLD.     

A pilot study evaluating non‐contact low‐frequency ultrasound and underlying molecular mechanism on diabetic foot ulcers

Non‐contact low‐frequency ultrasound (NCLF‐US) devices have been increasingly used for the treatment of chronic non‐healing wounds. The appropriate dose for NCLF‐US is still in debate. The aims of this pilot study were to evaluate the relationship between dose and duration of treatment for subjects with non‐healing diabetic foot ulcers (DFUs) and to explore the correlation between wound healing and change of cytokine/proteinase/growth factor profile. This was a prospective randomised clinical study designed to evaluate subjects with non‐healing DFUs for 5 weeks receiving standard of care and/or NCLF‐US treatment. Subjects were randomly assigned to one of the three groups: application of NCLF‐US thrice per week (Group 1), NCLF‐US once per week (Group 2) and the control (Group 3) that received no NCLF‐US. All subjects received standard wound care plus offloading for a total of 4 weeks. Percent area reduction (PAR) of each wound compared with baseline was evaluated weekly. Profiles of cytokines/proteinase/growth factors in wound fluid and biopsied tissue were quantified to explore the correlation between wound healing and cytokines/growth factor expression. Twelve DFU patients, 2 (16·7%) type 1 and 10 (83·3%) type 2 diabetics, with an average age of 58 ± 10 years and a total of 12 foot ulcers were enrolled. Average ulcer duration was 36·44 ± 24·78 weeks and the average ABI was 0·91 ± 0·06. Group 1 showed significant wound area reduction at weeks 3, 4 and 5 compared with baseline, with the greatest PAR, 86% (P < 0·05); Groups 2 and 3 showed 25% PAR and 39% PAR, respectively, but there were no statistically significant differences between Groups 2 and 3 over time. Biochemical and histological analyses indicated a trend towards reduction of pro‐inflammatory cytokines (IL‐6, IL‐8, IL‐1β, TNF‐α and GM‐CSF), matrix metalloproteinase‐9 (MMP‐9), vascular endothelial growth factor (VEGF) and macrophages in response to NCLF‐US consistent with wound reduction, when compared with control group subjects. This proof‐of‐concept pilot study demonstrates that NCLF‐US is effective in treating neuropathic diabetic foot ulcers through, at least in part, inhibiting pro‐inflammatory cytokines in chronic wound and improving tissue regeneration. Therapeutic application of NFLU, thrice (3) per week, renders the best wound area reduction.     

Increased gene expression of TGF‐β in peripheral blood mononuclear cells from renal transplant patients with polyomavirus BK viremia

We aimed to investigate the roles of cytokines during polyomavirus BK (BKV) reactivation in renal transplant patients. Forty‐eight renal allograft recipients were enrolled, and their sera BKV viral load and mRNA expression levels of cytokines in peripheral blood mononuclear cells were measured by real‐time polymerase chain reaction. Patient's age and gene expression levels of interleukin (IL)‐2 (10.04 ± 2.63 vs. 8.70 ± 2.40, p = 0.049) and transforming growth factor (TGF)‐β (12.58 ± 2.59 vs. 10.89 ± 1.91, p = 0.015) were significantly higher in BKV viremia (+) renal transplant patients. Multivariate logistic regression analysis revealed that age and mRNA expression levels of TGF‐β, but not IL‐2, significantly correlated with the presence of BKV viremia. Sera BKV viral loads showed a positive correlation with patient age and the levels of TGF‐β and IL‐6 mRNA. After adjusting for age and sex in the regression model, both age and TGF‐β mRNA levels maintained a significant positive association with sera BKV viral loads. Serum TGF‐β concentration tended to be higher in BKV viremia (+) patients (p = 0.079). In conclusion, expression levels of TGF‐β were found to correlate with both BKV viremia positivity and sera BKV viral loads in renal transplant patients.     

Inflammatory and anti‐inflammatory cytokines in the seminal plasma of infertile men suffering from varicocele

Varicocele is one of causes of the declined sperm quality and low sperm production, which can lead to infertility in males. There are several experimental and epidemiological findings which support the idea that inflammatory mechanisms play an essential role in varicocele pathogenesis. Besides, in this pathological state, interleukin‐37 (IL‐37) as an anti‐inflammatory cytokine is able to bind interleukin‐18‐binding protein (IL‐18BP), and subsequently binds IL‐18 receptor β, inhibiting the pro‐inflammatory activity of IL‐18. To explore the interaction between IL‐37 and IL‐18 in infertility, we measured the amount of these cytokines in the seminal fluid of infertile men affected by varicocele. The seminal plasma levels of IL‐37 and IL‐18 were measured in 75 infertile men with varicocele and 75 healthy fertile controls (age range, 30–48 years) using enzyme‐linked immunosorbent assay. The seminal levels of IL‐37 and IL‐18 were significantly increased in infertile men with varicocele when compared to fertile controls (p < .0001). Because of the essential role(s) of cytokines in inflammatory response of cell systems, it could be possible that sperm motility is reduced following increased IL‐18, activated neutrophils and reactive oxygen species in semen of infertile patients with varicocele. Moreover, the results of this study indicated that interaction between IL‐37 and IL‐18Rβ can lead to reduced inflammatory responses. It seems that IL‐37 might be a potential biomarker and therapeutic target for male infertility.     

Diagnostic accuracy of neutrophil‐derived circulating free DNA (cf‐DNA/NETs) for septic arthritis

The release of “neutrophil extracellular traps” (NETs) has been identified as a novel immune response in innate immunity. NETs are composed of neutrophil‐derived circulating free DNA (cf‐DNA) and neutrophil cytoplasm‐derived proteins such as proteases. In this study, we analyzed the putative diagnostic value of synovial cf‐DNA/NETs for identification of septic arthritis. Forty‐two patients with a joint effusion who had undergone arthrocentesis were included. From synovial fluid, cf‐DNA/NETs (j‐cf‐DNA) levels were directly quantified. Diagnostic value of j‐cf‐DNA was compared with white blood cells (WBC), synovial white blood cells (j‐WBC), C‐reactive protein (CRP), j‐IL‐6, j‐TNF alpha, j‐IL‐1 beta, and myeloperoxidase (j‐MPO). Sensitivity, specificity, positive and negative predictive value, as well as ROC‐curves for each parameter were calculated. Synovial fluid cf‐DNA/NETs values from patients with septic arthritis (3,286 ± 386 ng/ml, n = 9) were significantly increased compared to patients with noninfectious joint inflammation (1,040 ± 208 ng/ml, n = 17) or osteoarthritis (278 ± 34 ng/ml, n = 16, p < 0.01). In conjunction with j‐cf‐DNA, j‐IL‐6 and j‐IL‐1 beta were significantly elevated (p < 0.01), but WBC, CRP, and j‐WBC were not. At a cut‐off of 300 ng/ml, j‐cf‐DNA had a sensitivity of 0.89, a specificity of 1.0, a positive predictive value of 1.0, and a negative predictive value of 0.97. Receiver operation curves revealed largest areas under the curve for cf‐DNA/NETs (0.933) and j‐IL‐6 (0.951). cf‐DNA/NETs seem to be a valuable additional marker for the diagnosis of septic arthritis or periprosthetic infections. However, this result should be confirmed in a large clinical trial. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1401–1407, 2009     

3D MRI quantification of femoral head deformity in Legg–Calvé–Perthes disease

The purpose of this study was to quantify femoral head deformity in patients with Legg–Calvé–Perthes disease (LCPD) using a novel three dimensional (3D) magnetic resonance imaging (MRI) reconstruction and volume based analysis. Bilateral femoral heads of 17 patients (mean age 9.9 ± 2.0 years; 12 boys, 5 girls) with LCPD were scanned 1–2 times (n = 33 LCPD heads, 20 normal heads) using a 1.5T MRI scanner. Fourteen patients had unilateral and three had bilateral LCPD with five hips in the Waldenström initial stage, 9 in the fragmentation stage, 14 in the reossification stage, and 5 in the healed stage. 3D digital reconstructions of femoral heads were created using MIMICS software. Deformity was quantified using a 3D volume ratio method based on reference hemisphere volume as well as two surface geometry methods. Intra‐observer analysis showed that 97% of the LCPD femoral heads were within 10% of the original value and test shapes had 99.6% accuracy. For normal femoral heads, the volume ratios of all except one were between 95 and 98% (n = 20) of a perfect hemisphere volume. For femoral heads affected with LCPD, the volume ratios ranged from 43% to 96% of a perfect hemisphere (n = 33). The volume ratio method and the two surface geometry comparison methods had high correlation (r = 0.89 and 0.96). In summary, the 3D MRI volume ratio method allowed accurate quantification and demonstrated small changes (<10%) of the femoral head deformity in LCPD. This method may serve as a useful tool to evaluate the effects of treatment on femoral head shape. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2051–2058, 2017.

     

Influence of the anti‐inflammatory cytokine interleukin‐4 on human joint capsule myofibroblasts

Post‐traumatic joint contracture was reported to be associated with elevated numbers of contractile myofibroblasts (MFs) in the healing capsule. During the physiological healing process, the number of MFs declines; however, in fibroconnective disorders, MFs persist. The manifold interaction of the cytokines regulating the appearance and persistence of MFs in the pathogenesis of joint contracture remains to be elucidated. The objective of our current study was to analyze the impact of the anti‐inflammatory cytokine interleukin (IL)‐4 on functional behavior of MFs. Cells were isolated from human joint capsule specimens and challenged with three different concentrations of IL‐4 with or without its neutralizing antibody. MF viability, contractile properties, and the gene expression of both alpha‐smooth muscle actin (α‐SMA) and collagen type I were examined. Immunofluorescence staining revealed the presence of IL‐4 receptor (R)‐alpha (α) on the membrane of cultured MFs. The cytokine IL‐4 promoted MF viability and enhanced MF modulated contraction of collagen gels. Moreover, IL‐4 intervened in gene expression by up‐regulation of α‐SMA and collagen type I mRNA. These effects could be specifically lowered by the neutralizing IL‐4 antibody. On the basis of our findings we conclude that the anti‐inflammatory cytokine IL‐4 specifically regulates viability and the contractile properties of MFs via up‐regulating the gene expression of α‐SMA and collagen type I. IL‐4 may be a helpful target in developing anti‐fibrotic therapeutics for post‐traumatic joint contracture in human. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1290–1298, 2017.

     

Correlation between MRI and hip arthroscopy in children with Legg–Calve–Perthes disease

Background

Most of the information available about Legg–Calve–Perthes disease (LCPD) at present is gained through imaging modalities including plain radiographs and magnetic resonance imaging (MRI). But the accuracy of MRI in this disease and its predictive value to reveal various intra-articular pathologies is not known. We correlated the findings of MRI with those seen on hip arthroscopy in children with active stage of LCPD.

Methods

We conducted a prospective observational study in which MRI findings were correlated with corresponding findings on hip arthroscopy in a cohort of 25 patients of active LCPD below 12 years of age. The parameters noted on MRI included status of ligamentum teres, status of the labrum, synovial effusion if any, condition of the femoral and acetabular articular cartilage including chondral flaps, chondral indentation and intra-articular loose bodies. The indication of performing hip arthroscopy was persistent severe hip pain (Wong–Baker FACES pain scale ≥ 3) after 6 months of conservative management. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for MRI considering arthroscopy as a gold standard.

Results

Synovial effusion was seen in a large number of patients on both MRI (17) and hip arthroscopy (24). The sensitivity (95% confidence interval) of MRI was found to be low, especially with respect to labral tears [25% (0.63–80.6)] and intra-articular loose bodies [20% (0.51–71.6)]. NPV for synovial effusion was also found to be low [12.5% (0.32–52.7)], although specificity and PPV of MRI were found to be good for all the parameters.

Conclusions

MRI cannot be completely relied upon for identifying all the intra-articular pathologies in children with LCPD, although it has a good complimentary role. In patients with severe persistent pain with suspicion for joint changes, hip arthroscopy can provide a safe and efficient procedure (better than MRI) for eliciting the associated joint pathology.

     

Characterization of macrophage polarizing cytokines in the aseptic loosening of total hip replacements

Aseptic loosening of hip replacements is driven by the macrophage reaction to wear particles. The extent of particle‐induced macrophage activation is dependent on the state of macrophage polarization, which is dictated by the local cytokine microenvironment. The aim of the study was to characterize cytokine microenvironment surrounding failed, loose hip replacements with an emphasis on identification of cytokines that regulate macrophage polarization. Using qRT‐PCR, the expression of interferon gamma (IFN‐γ), interleukin‐4 (IL‐4), granulocyte–macrophage colony‐stimulating factor (GM‐CSF), IL‐13, and IL‐17A was low and similar to the expression in control synovial tissues of patients undergoing primary hip replacement. Using immunostaining, no definite source of IFN‐γ or IL‐4 could be identified. IL‐17A positive cells, identified as mast cells by double staining, were detected but their number was significantly reduced in interface tissues compared to the controls. Significant up‐regulation of IL‐10, M‐CSF, IL‐8, CCL2‐4, CXCL9‐10, CCL22, TRAP, cathepsin K, and down regulation of OPG was seen in the interface tissues, while expression of TNF‐α, IL‐1β, and CD206 were similar between the conditions. It is concluded that at the time of the revision surgery the peri‐implant macrophage phenotype has both M1 and M2 characteristics and that the phenotype is regulated by other local and systemic factors than traditional macrophage polarizing cytokines. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1241–1246, 2014.     

Anti‐inflammatory effect of platelet‐rich plasma on nucleus pulposus cells with response of TNF‐α and IL‐1

The purpose of this study was to investigate the anti‐inflammatory effect of platelet‐rich plasma (PRP) with collagen matrix on human nucleus pulposus (NP) cell in response to pro‐inflammatory cytokines such as tumor necrosis factor‐alpha (TNF‐α) and interleukin‐1 (IL‐1). NP cells from human disks were cultured in a monolayer and maintained in the collagen matrix prior to the addition of recombinant human IL‐1 and TNF‐α. After applying IL‐1 and TNF‐α, PRP prepared by using a commercially available platelet concentration system was added. The response was investigated using real‐time PCR for mRNA expression of type II collagen, aggrecan, matrix metalloproteinase‐3 (MMP‐3), and cyclooxygenase‐2 (COX‐2). The combination of IL‐1β and TNF‐α led to decrease of matrix synthesis gene expression such as collagen type II and aggrecan and increase of the degradation gene expression of COX‐2 and MMP‐3, compared to the control. Consecutive PRP exposure significantly recovered the down‐regulated gene expression of collagen type II and aggrecan and significantly reduced the increased MMP‐3 and COX‐2 gene expression, compared to that of control groups with pro‐inflammatory cytokines. The administration of PRP with collagen matrix markedly suppressed cytokine‐induced pro‐inflammatory degrading enzymes and mediators in the NP cell. It also rescued gene expression concerning matrix synthesis, thereby stabilizing NP cell differentiation. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:551–556, 2014.     

Autologous protein solution inhibits MMP‐13 production by IL‐1β and TNFα‐stimulated human articular chondrocytes

Catabolic inflammatory cytokines are prevalent in osteoarthritis (OA). The purpose of this study was to evaluate an autologous protein solution (APS) as a potential chondroprotective agent for OA therapy. APS was prepared from platelet‐rich plasma (PRP). The APS solution contained both anabolic (bFGF, TGF‐β1, TGF‐β2, EGF, IGF‐1, PDGF‐AB, PDGF‐BB, and VEGF) and anti‐inflammatory (IL‐1ra, sTNF‐RI, sTNF‐RII, IL‐4, IL‐10, IL‐13, and IFNγ) cytokines but low concentrations of catabolic cytokines (IL‐1α, IL‐1β, TNFα, IL‐6, IL‐8, IL‐17, and IL‐18). Human articular chondrocytes were pre‐incubated with the antagonists IL‐1ra, sTNF‐RI, or APS prior to the addition of recombinant human IL‐1β or TNFα. Following exposure to inflammatory cytokines, the levels of MMP‐13 in the culture medium were evaluated by ELISA. MMP‐13 production stimulated in chondrocytes by IL‐1β or TNFα was reduced by rhIL‐1ra and sTNF‐RI to near basal levels. APS was also capable of inhibiting the production of MMP‐13 induced by both IL‐1β and TNFα. The combination of anabolic and anti‐inflammatory cytokines in the APS created from PRP may render this formulation to be a potential candidate for the treatment of inflammation in patients at early stages of OA. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1320–1326, 2011     

Potential pathological role of pro‐inflammatory cytokines (IL‐6, TNF‐α, and IL‐17) in xenotransplantation

The major limitation of organ transplantation is the shortage of available organs from deceased human donors which leads to the deaths of thousands of patients each year. Xenotransplantation is considered to be an effective way to resolve the problem. Immune rejection and coagulation dysfunction are two major hurdles for the successful survival of pig xenografts in primate recipients. Pro‐inflammatory cytokines, such as IL‐6, TNF‐α, and IL‐17, play important roles in many diseases and in allotransplantation. However, the pathological roles of these pro‐inflammatory cytokines in xenotransplantation remain unclear. Here, we briefly review the signaling transduction and expression regulation of IL‐6, TNF‐α, and IL‐17 and evaluate their potential pathological roles in in vitro and in vivo models of xenotransplantation. We found that IL‐6, TNF‐α, and IL‐17 were induced in most in vitro or in vivo xenotransplantation model. Blockade of these cytokines using gene modification, antibody, or inhibitor had different effects in xenotransplantation. Inhibition of IL‐6 signaling with tocilizumab decreased CRP but did not increase xenograft survival. The one possible reason is that tocilizumab can not suppress IL‐6 signaling in porcine cells or organs. Other drugs which inhibit IL‐6 signaling need to be investigated in xenotransplantation model. Inhibition of TNF‐α was beneficial for the survival of xenografts in pig‐to‐mouse, rat, or NHP models. Blockade of IL‐17 using a neutralizing antibody also increased xenograft survival in several animal models. However, the role of IL‐17 in the pig‐to‐NHP xenotransplantation model remains unclear and needs to be further investigated. Moreover, blockade of TNF‐α and IL‐6 together has got a better effect in pig‐to‐baboon kidney xenotransplantation. Blockade two or even more cytokines together might get better effect in suppressing xenograft rejection. Better understanding the role of these cytokines in xenotransplantation will be beneficial for choosing better immunosuppressive strategy or producing genetic modification pig.