The cytokine expression in synovial membrane and the relationship with pain and pathological findings at hip arthroscopy

Mast Cells Mediate Acute Inflammatory Responses After Glenoid Labral Tears and Can Be Inhibited With Cromolyn in a Rat Model

BACKGROUND

Injuries to the glenoid labrum have been recognized as a source of joint pain and discomfort, which may be associated with the inflammatory responses that lead to the deterioration of labral tissue. However, it is unclear whether the torn labrum prompts mast cell (MC) activation, resulting in synovial inflammatory responses that lead to labral tissue degeneration.

PURPOSE

To determine the potential influence of activated MC on synovial inflammatory responses and subsequent labral tissue degeneration and shoulder function deterioration in a rat model by monitoring MC behavior and sequential inflammatory responses within the synovial tissue and labral tissue after injury, suture repair, and MC stabilizer administration.

STUDY DESIGN

Controlled laboratory study.

METHODS

Anteroinferior glenoid labral tears were generated in the right shoulder of rats (n = 20) and repaired using a tunneled suture technique. Synovial tissue inflammatory responses were modulated in some rats with intraperitoneal administration of an MC stabilizer-cromolyn (n = 10). At weeks 1 and 3, MC activation, synovial inflammatory responses, and labral degeneration were histologically evaluated. Simultaneously, gait analysis was performed before and after surgical repair to assess the worsening of the shoulder function after the injury and treatment.

RESULTS

Resident MC degranulation after labral injury (50.48% ± 8.23% activated at week 1) contributed to the initiation of synovial tissue inflammatory cell recruitment, inflammatory product release, matrix metalloproteinase-13, and subsequent labral tissue extracellular matrix degeneration. The administration of cromolyn, an MC stabilizer, was found to significantly diminish injury-mediated inflammatory responses (inflammatory cell infiltration and subsequent proinflammatory product secretion) and improve shoulder functional recovery.

CONCLUSION

MC activation is responsible for labral tear-associated synovial inflammation and labral degeneration. The administration of cromolyn can significantly diminish the cascade of inflammatory reactions after labral injury.

CLINICAL RELEVANCE

Our findings support the concept that MC stabilizers may be used as a complementary therapeutic option in the treatment and repair of labral tears.

Correlation between CD163 expression and resting pain in patients with hip osteoarthritis: Possible contribution of CD163+ monocytes/macrophages to pain pathogenesis

Expression of CD163, a scavenger receptor specifically expressed by monocytes and macrophages, is elevated in the synovial tissue of patients with knee osteoarthritis (OA) compared with healthy controls. However, the association between CD163 expression in the synovium and pain in OA patients is unclear. We investigated the correlation between synovial CD163 expression and resting and active pain levels in patients with hip osteoarthritis (HOA). To investigate the possible contribution of CD163+ subsets to pain pathogenesis, we compared pain-related cytokine expression and M1/M2 macrophage marker expression in CD163+ and CD163- cells. We performed flow cytometric analysis to study the CD163+ cell population. We also examined pain-related cytokine expression and M1/M2 macrophage marker expression on CD163+ CD14^high and CD163+ CD14^low cells using cell sorting. Synovial CD163 expression significantly correlated with resting pain levels (p = 0.006; R = 0.321), but not active pain levels (p = 0.155; R = 0.169). Expression of the M1 macrophage marker CD80 was significantly higher in CD163+ than CD163- cells (p = 0.010), as was the expression of M2 macrophage markers CD206 and IL10 (CD206, p = 0.014; IL10, p = 0.005), and TNFA and IL1B (TNFA, p = 0.002; IL1B, p = 0.001). TNFA expression was significantly higher in CD163+ CD14^low than CD163+ CD14^high cells, while IL1B, IL10, and CD206 expression were comparable among these subsets. Our findings suggest that CD163 expression is associated with higher resting pain scores. As TNF-α plays a role in the pain process, CD163+ CD14^low cells expressing TNFA may be a potent contributor to the pathogenesis of resting pain in HOA.

A High Body Mass Index and the Vacuum Phenomenon Upregulate Pain-Related Molecules in Human Degenerated Intervertebral Discs

Animal studies suggest that pain-related-molecule upregulation in degenerated intervertebral discs (IVDs) potentially leads to low back pain (LBP). We hypothesized that IVD mechanical stress and axial loading contribute to discogenic LBP’s pathomechanism. This study aimed to elucidate the relationships among the clinical findings, radiographical findings, and pain-related-molecule expression in human degenerated IVDs. We harvested degenerated-IVD samples from 35 patients during spinal interbody fusion surgery. Pain-related molecules including tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, calcitonin gene-related peptide (CGRP), microsomal prostaglandin E synthase-1 (mPGES1), and nerve growth factor (NGF) were determined. We also recorded preoperative clinical findings including body mass index (BMI), Oswestry Disability Index (ODI), and radiographical findings including the vacuum phenomenon (VP) and spinal instability. Furthermore, we compared pain-related-molecule expression between the VP (−) and (+) groups. BMI was significantly correlated with the ODI, CGRP, and mPGES-1 levels. In the VP (+) group, mPGES-1 levels were significantly higher than in the VP (−) group. Additionally, CGRP and mPGES-1 were significantly correlated. Axial loading and mechanical stress correlated with CGRP and mPGES-1 expression and not with inflammatory cytokine or NGF expression. Therefore, axial loading and mechanical stress upregulate CGRP and mPGES-1 in human degenerated IVDs, potentially leading to chronic discogenic LBP.

Role of CD14-positive cells in inflammatory cytokine and pain-related molecule expression in human degenerated intervertebral discs

Multiple human and animal studies suggest that the upregulation of inflammatory cytokines and other pain-related molecules in degenerated or injured intervertebral discs (IVDs) may cause discogenic low back pain (LBP). We previously reported that macrophages in injured IVD in mice produced inflammatory cytokines, but not other pain-related molecules. CD14 is a monocyte marker expressed mainly by macrophages. The aim of the current study was to evaluate the role of CD14-positive cells in inflammatory cytokine and pain-related molecule expression in human degenerated IVD. IVD samples were harvested from 14 patients, including 10 with lumbar spinal stenosis, four with adult spinal deformity, and one with lumbar disc herniation during spinal interbody fusion surgery. Harvested IVD-derived mononuclear cells were obtained and CD14-positive (+) and CD14-negative (-) cells were separated using CD14 antibody and streptavidin-labeled magnetic beads. Inflammatory cytokines messenger RNA (mRNA) in the CD14(+) and CD14(-) cells, including tumor necrosis factor ɑ (TNFA), in, terleukin-1β (IL1B) and IL6, were determined using quantitative polymerase chain reaction (qPCR) and their expression levels were compared. To evaluate factors controlling the regulation of pain-related molecules mRNA expression, cultured CD14(-) and CD14(+) cells from IVDs were stimulated with recombinant human TNF-ɑ and IL-1β and levels of pain-related molecules, including calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) were determined using qPCR. Levels of TNFA, IL1B, IL6, and NGF in CD14(+) cells were significantly increased compared with those in CD14(-) cells (TNFA, p = 0.006; IL1B, p = .017; IL6, p = .010; NGF, p = .027). Following TNFA stimulation, NGF levels were significantly increased in CD14(-) and CD14(+) cells (CD14(-), p = .003; CD14(+), p < .001) and CGRP was significantly increased in CD14(-) IVD cells (p = .040). Following IL1B stimulation, NGF levels were significantly increased in CD14(-) cells (p = .004). CD14(+) cells had higher TNFA, IL1B, IL6, and NGF expressions than CD14(-) cells in human degenerated IVDs. Additionally, TNFA stimulation promoted the upregulation of NGF and CGRP in CD14(-) cells. These findings suggested that CD14(+) cells directly and indirectly contributed to inflammatory cytokine and pain-related molecule expression in human degenerated IVD. CD14(+) cells might be important in the pathological mechanism of chronic discogenic LBP in humans.

Matrix Metalloproteinase 3: A Promoting and Destabilizing Factor in the Pathogenesis of Disease and Cell Differentiation

Cells must alter their expression profiles and morphological characteristics but also reshape the extracellular matrix (ECM) to fulfill their functions throughout their lifespan. Matrix metalloproteinase 3 (MMP-3) is a member of the matrix metalloproteinase (MMP) family, which can degrade multiple ECM components. MMP-3 can activate multiple pro-MMPs and thus initiates the MMP-mediated degradation reactions. In this review, we summarized the function of MMP-3 and discussed its effects on biological activities. From this point of view, we emphasized the positive and negative roles of MMP-3 in the pathogenesis of disease and cell differentiation, highlighting that MMP-3 is especially closely involved in the occurrence and development of osteoarthritis. Then, we discussed some pathways that were shown to regulate MMP-3. By writing this review, we hope to provide new topics of interest for researchers and attract more researchers to investigate MMP-3.

Potential anti-inflammatory and anti-apoptotic effect of Coccinia grandis plant extract in LPS stimulated-THP-1 cells

Coccinia grandis (C. grandis) L is an Indian medicinal plant from the Cucurbitaceae family whose extracts possess anti-oxidant, anti-infective, and anti-inflammatory properties. The objective of the present study was to probe the potential immunomodulatory of C. grandis crude extract on different pathways in THP-1 cells as probed by changes in expression of several proteins. THP-1 cells were differentiated into macrophages after treatment with phorbol-12-myristate 13-acetate, followed by exposure to lipopolysaccharide (LPS) with or without 50 or 100 μg/ml of C. grandis extract. Treatment of the cells with the extract significantly downregulated the expression and release of pro-inflammatory cytokines (IL-6, IL-1β, CCL2, CCL22, CXCL10/IP-10, CX3CL1 and CXCL8/IL-8), proteins (ERK5, BAX, BCL2, Cyclin D, ERK1, NF-κB, P-IκBα,P- NF-κB and P-p38) and molecular signaling pathways (NF-κB, p38 MAPK, ERK1/2 and IL-6/JAK/STAT3 signaling cascades). This study is the first to highlight the ability of C. grandis extract to modulate several pathways, including proliferation, the expression of inflammatory cytokines, phagocytosis, migration properties and apoptosis, in human monocytic THP-1 cells.

Divergent Mononuclear Cell Participation and Cytokine Release Profiles Define Hip and Knee Osteoarthritis

Osteoarthritis (OA) is a progressive joint disease driven by a blend of inflammatory and biomechanical processes. Studies using human samples to understand inflammatory mechanisms in OA frequently recruit OA patients with different affected joints, even though recent evidence indicates that OA is a heterogeneous disease which only culminates in a common end point. Differences in age of onset and the dynamics of disease progression suggest that different joints may represent different disease entities, thereby diluting the discovery potential in a combined analysis. We hypothesized that different OA joints may also differ in immunopathology within the synovium. To investigate this hypothesis, we profiled the immune cell contribution (flow cytometry) and cytokine release profiles (ELISA) in purified synovial membrane mononuclear cells from 50 patients undergoing either hip (n = 34) or knee (n = 16) replacement surgery. Unsupervised computational approaches were used for disease deconstruction. We found that hip and knee osteoarthritis are not identical in respect to the inflammatory processes that take place in the synovial membrane. Instead, we report that principally CD14⁺ macrophages are expanded fourfold in the synovial membrane of patients with knee OA compared to hip OA, with a trend to higher expression in CD8⁺ T cells, while CD4⁺ T cells, B cells, and NK cells were found at comparable quantities. Upon isolation and culture of cells from synovial membrane, isolates from hip OA released higher concentrations of Eotaxin (CCL11), G-CSF, GM-CSF, INF-γ, IP-10 (CXCL10), TNF-α, MIP-1α (CCL3), MIP-1β (CCL4), IL-4, IL-10, IL-17, and lower concentrations of stem cell factor (SCF), thereby highlighting the difference in the nature of hip and knee osteoarthritis. Taken together, this study establishes hip and knee OA as immunologically distinct types of OA, and creates a resource of the cytokine expression landscape and mononuclear cell infiltration pattern of patients with hip and knee osteoarthritis.

Biomarkers for Femoroacetabular Impingement and Hip Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND

The early recognition and management of patients with hip lesions, such as femoroacetabular impingement (FAI) and early hip osteoarthritis (OA), may preempt significant hip morbidity. The identification of reliable biomarkers may help guide decision making in an efficient and cost-effective manner.

PURPOSE

To determine the biomarkers that have been associated with FAI as well as identify serum, synovial, and urinary analytes that have shown clinical utility in the prediction or identification of hip OA.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

The terms "hip arthroscopy," "femoroacetabular impingement," "labral tear," "osteoarthritis," and "biomarker" were searched in PubMed, Web of Science, Scopus, Cochrane Library, and Google Scholar, yielding 276 articles. After screening, 7 articles were included. Pooled estimates were calculated utilizing a fixed-effects inverse-variance model weighted for individual study size.

RESULTS

A total of 1747 patients with a mean age of 37.5 ± 4.5 years (76.4% female) were identified. Forty-three unique biomarkers were assessed. Although general proinflammatory cytokines IL-1 and TNF-α exhibited inconsistent trends in arthritic hips, IL-6 demonstrated a consistent increase (+84.8% [95% CI, 81.9%-87.6%]; P < .05). A significant difference was found in levels of the fibronectin-aggrecan complex (FAC) in patients with OA compared with controls (0.08 ± 0.40 vs 1.15 ± 0.35 μg/mL, respectively; P < .001). It was the only specific analyte to show a significant difference between those with and without OA. In the setting of FAI, cartilage oligomeric matrix protein (COMP) was significantly increased in athletes after adjusting for concurrent knee and hip OA. A statistically significant difference was present in FAI-positive hips (9.0 ± 0.1 [95% CI, 8.8-9.3]) compared with controls (8.4 ± 0.1 [95% CI, 8.2-8.4]) (P < .05). Other biomarkers, such as CXCL3, which exhibited statistically significant differences compared with controls, did not control for underlying factors such as age and concomitant lesions.

CONCLUSION

COMP and FAC are specific biomarkers with potential utility in the diagnosis and management of FAI and hip OA, given their ability to differentiate between controls and patients with hip lesions. Further research is necessary to identify their ability in determining disease severity, predicting the response to treatment, and establishing an association with the risk of long-term OA.

Kafirin from Sorghum bicolor inhibition of inflammation in THP-1 human macrophages is associated with reduction of intracellular reactive oxygen species

Aberrant inflammation as a result of activation of the transmembrane protein Toll-like receptor 4 belonging to pattern recognition receptor and subsequent phosphorylation of signaling proteins facilitated by reactive oxygen species has been linked to a myriad of diseases. Sorghum is a drought-resistant cereal with health promoting properties associated with its biologically active substances such as kafirin. Kafirin is an alcohol soluble protein and accounts for as much as 70% of the total proteins in sorghum. The objective was to determine the effect of kafirin on lipopolysaccharide (LPS)-induced inflammation in THP-1 human macrophages. THP-1 human monocytic leukemia cells were differentiated into macrophages by phorbol-12-myristate 13-acetate followed by treatment of LPS with or without 50 μg/mL or 100 μg/mL concentrations of kafirin. Kafirin at 100 μg/mL reduced the production of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α by 28.3%, 74.0%, and 81.4%, respectively. Kafirin reduced production of intracellular reactive oxygen species is associated with reduced phosphorylation of extracellular regulated kinase1/2 and c-JUN N-terminal kinase and nuclear translocation of p65 and c-JUN transcription factors. Our results showed for the first time the anti-inflammatory property of kafirin purified from sorghum in LPS-induced THP-1 human macrophages.