Protective effect of low dose intra-articular cadmium on inflammation and joint destruction in arthritis

An organic state trace element solution for rheumatoid arthritis treatment by modulating macrophage phenotypic from M1 to M2

Trace elements (TEs) are essential for the treatment of rheumatoid arthritis (RA). This study aimed to prepare a TEs solution enriched with various organic states to evaluate its preventive, therapeutic effects, and mechanism of action in RA and to provide a treatment method for RA treatment. The TEs in natural ore were extracted and added to 0.5% (W/V) L-alanyl-L-glutamine (LG) to obtain a TEs solution (LG-WLYS), which was examined for its concentration and quality. The antioxidant properties and effects of LG-WLYS on cell behavior were evaluated at the cellular level. The preventive and therapeutic effects and mechanism of action of LG-WLYS in rats with RA were explored. The LG-WLYS solution was clear, free from visible foreign matter, and had a pH of 5.33 and an osmolality of 305.67 mOsmol/kg. LG-WLYS inhibited cell migration and angiogenesis. LG-WLYS solution induced macrophages to change from M1-type to M2-type, increased the content of antioxidant enzymes (glutathione, superoxide dismutase, and IL-10), decreased the levels of nitric oxide, malondialdehyde, TNF-α, IL-1β, IL-6, COX-2, and iNOs, scavenging reactive oxygen species from the lesion site, inhibiting the apoptosis of chondrocytes, regulating inflammatory microenvironment, and decreasing inflammation response to exert the therapeutic effect for RA. In conclusion, LG-WLYS has outstanding therapeutic and preventive effects against RA and has enormous potential for further development.

The association of trace elements with arthritis in US adults: NHANES 2013-2016

BACKGROUND

Arthritis is a common chronic disease, and is a major cause of disability and chronic pain in adults. Considering inflammatory responses is closely related with trace elements (TEs), the role of TEs in arthritis has attracted much attention. This study aimed to assess the association between TEs and arthritis.

METHODS

Concentrations of TEs in whole blood [cadmium (Cd), lead (Pb), mercury (Hg), selenium (Se), and manganese (Mn)] and serum [copper (Cu) and zinc (Zn)] were measured in adults who participated in the US National Health and Nutrition Examination Survey. Logistic regression model and Bayesian kernel machine regression model were used to explore the association between TEs and arthritis.

RESULTS

The levels of five TEs (Pb, Hg, Cd, Se, and Cu) in the arthritis group changed significantly. Three TEs were found to be associated with an increased risk of arthritis: Pb [OR (95% CI): 2.96 (2.18, 4.03), p-value for trend (P-t) < 0.001], Cd [OR (95% CI): 2.28 (1.68, 3.11), P-t < 0.001], Cu [OR (95% CI): 2.05 (1.53, 2.76), P-t < 0.001]. The Relative Excess Risk of Interaction was 0.35 (95% CI: 0.06-0.65) and 0.38 (95% CI: 0.11-0.64), respectively, suggesting that Hg ions and Se ions have positive additional interactions with alcohol consumption, which reduced the risk of arthritis. Subgroup analysis showed that Pb ions and Cd ions were significantly correlated with osteoarthritis and rheumatoid arthritis.

CONCLUSION

Elevated concentrations of Pb, Cd, and Cu were associated with increased risk of arthritis. Drinking with high levels of Hg or Se may be a protective factor for arthritis. Future studies are warranted to validate these findings in prospective studies.

Crosstalk between fibroblasts and T cells in immune networks

Fibroblasts are primarily considered as cells that support organ structures and are currently receiving attention for their roles in regulating immune responses in health and disease. Fibroblasts are assigned distinct phenotypes and functions in different organs owing to their diverse origins and functions. Their roles in the immune system are multifaceted, ranging from supporting homeostasis to inducing or suppressing inflammatory responses of immune cells. As a major component of immune cells, T cells are responsible for adaptive immune responses and are involved in the exacerbation or alleviation of various inflammatory diseases. In this review, we discuss the mechanisms by which fibroblasts regulate immune responses by interacting with T cells in host health and diseases, as well as their potential as advanced therapeutic targets.

Evaluation of some trace elements and antioxidants in sera of patients with rheumatoid arthritis: a case-control study

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease that destroys joints. The concentrations of elements (Zn, Cu, Mg, Mn, Fe, Ni, Cr, K, Na, Ca, Pb, and Cd), as well as antioxidant glutathione GSH and lipid peroxidation marker malondialdehyde MDA, will be determined in this study.

METHOD

The study involves 120 female RA patients and 60 healthy females in the control group, all of whom are between the ages of 20 and 60. Patients having diabetes, hypertension, hyperthyroidism, or psoriasis, in addition to RA, were excluded.

RESULTS

When RA patients were compared to healthy individuals, the levels of Cu, Ni, Na, Pb, and Cd were significantly higher (p < 0.01), whereas the levels of Zn, Mg, Mn, Cr, Ca, K, and Fe were significantly lower (p < 0.01). The Cu/Zn (2.21 and 1.16) and Na/k (38.67 and 34.87) ratios were also found to be significantly higher in RA patients compared to controls. Furthermore, the data indicated that GSH concentrations in RA patients were significantly lower (p < 0.01) than those in controls (655.90 and 1345.17 mol/l, respectively). MDA levels in RA patients were significantly higher (p < 0.01) than those in controls (2.739 and 1.673 mol/l, respectively).

CONCLUSIONS

The data indicate that Cu/Zn and Na/k ratios can be of great value in the diagnosis and evaluation of RA patients. On this basis, we conclude that these elements can be relied upon to provide indications of RA risk and the measurement of oxidative stress can serve as a biomarker to monitor disease activity and severity in RA patients. Key Points • Trace elements may be of value and may have an expected significance in the early diagnosis, prognosis, and treatment evaluation of rheumatoid arthritis. • The distortion in the levels of trace elements may reflect their possible role in the pathogenesis of rheumatoid arthritis. • Oxidative stress can act as a biomarker to monitor disease activity and severity in patients with rheumatoid arthritis. • The trace elements can contribute to the manifestation of inflammatory diseases due to their role in the synthesis of some antioxidants or due to their effect on the immune system.

Impact of Cadmium Mediated by Tobacco Use in Musculoskeletal Diseases

Tobacco use has a negative impact on health due to its relationship with the development of high-mortality diseases, such as pulmonary cancer. However, the effect of cadmium (Cd), present in tobacco smoke, on the development of joint diseases has been scarcely studied. The objective of this review is to discuss the evidence regarding the mechanisms by which Cd exposure, through tobacco smoke, may lead to the development of osteoarthritis (OA), osteoporosis (OP), and rheumatoid arthritis (RA). There's evidence suggesting a string association between moderate to severe OA development and tobacco use, and that a higher blood concentration of Cd can trigger oxidative stress (OS) and inflammation, favoring cartilage loss. At the bone level, the Cd that is inhaled through tobacco smoke affects bone mineral density, resulting in OP mediated by a decrease in the antioxidant enzymes, which favors the bone resorption process. In RA, tobacco use promotes the citrullination process through Cd exposure and increases OS and inflammation. Understanding how tobacco use can increase the damage at the articular level mediated by a toxic metal, i.e., Cd, is important. Finally, we propose prevention, control, and treatment strategies for frequently disabling diseases, such as OA, OP, and RA to reduce its prevalence in the population.

Synoviocytes from pigmented villonodular synovitis are less sensitive to cadmium-induced cell death than synoviocytes from rheumatoid arthritis

Pigmented villonodular synovitis (PVNS) is a rare inflammatory articular disease sharing common characteristics with rheumatoid arthritis (RA), notably hyperplasia of the synovium due to a hyperproliferation of synoviocytes, and with cancer owing to mutations of the CSF1/M-CCSF gene. Targeting synovium hyperplasia by the local delivery of Cadmium (Cd) has been already tested in vitro and in vivo models of RA and could be applied to PVNS. PVNS and RA synoviocytes were exposed to low doses of Cd. After different culture time points, a qualitative analysis was done by microscopy and quantitative measurements of apoptosis, cell viability and IL-6 production were carried. IL-6 production by PVNS synovial tissue was also quantified after Cd treatment with or without the presence of pro-inflammatory cytokines (IL-17 + TNF). Addition of Cd induced cell death in both PVNS (1 ppm) and RA (0.1 ppm) synoviocytes, which increased with time and Cd concentrations. Cd increased the percentage of apoptotic cells and decreased cell viability and IL-6 production. In all these experiments, PVNS synoviocytes were tenfold less sensitive to Cd than RA synoviocytes. Cd decreased IL-6 production by PVNS synovial tissue and its effect was enhanced with pro-inflammatory cytokines. In summary, PVNS synoviocytes show resistance to Cd-induced cell death and decreased inflammation. Intra-articular use of Cd could represent a potential therapeutic tool in PVNS.

Update on Tenosynovial Giant Cell Tumor, an Inflammatory Arthritis With Neoplastic Features

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to joint destruction and bone erosion. Even if many treatments were developed with success in the last decades, some patients fail to respond, and disease chronicity is still a burden. Mechanisms involved in such resistance may include molecular changes in stromal cells. Other explanations can come from observations of tenosynovial giant cell tumor (TGCT), first considered as an inflammatory arthritis, but with unusual neoplastic features. TGCT leads to synovium hypertrophy and hyperplasia with hemosiderin deposition. It affects young adults, resulting in secondary osteoarthritis and increased morbidity. TGCT shows clinical, histological and genetic similarities with RA but affecting a single joint. However, the monoclonality of some synoviocytes, the presence of translocations and rare metastases also suggest a neoplastic disease, with some features common with sarcoma. TGCT is more probably in an intermediate situation between an inflammatory and a neoplastic process, with a main involvement of the proinflammatory cytokine CSF-1/CSF1R signaling axis. The key treatment option is surgery. New treatments, derived from the RA and sarcoma fields, are emerging. The tyrosine kinase inhibitor pexidartinib was recently FDA-approved as the first drug for severe TGCT where surgery is not an option. Options directly targeting the excessive proliferation of synoviocytes are at a preclinical stage.

Highlights of Strategies Targeting Fibroblasts for Novel Therapies for Rheumatoid Arthritis

Synovial fibroblasts of rheumatoid arthritis (RA) play a critical role in perpetuation of chronic inflammation by interaction with immune and inflammatory cells and in cartilage and bone invasion, but current therapies for RA are not directly targeted fibroblasts. Selectively fibroblast targeted therapy has been hampered because of lack of fibroblast specific molecular signature. Recent advancement in technology enabled us to gain insightful information concerning RA synovial fibroblast subpopulations and functions. Exploring fibroblast targeted therapies have been focused on inducing cell death via fibroblast associated proteins; interrupting fibroblast binding to matrix protein; blocking intercellular signaling between fibroblasts and endothelial cells; inhibiting fibroblast proliferation and invasion; promoting cell apoptosis and inducing cellular senescence, and modulating fibroblast glucose metabolism. Translation into clinical studies of these fibroblast targeted strategies is required for evaluation for their clinical application, in particular for combination therapy with current immune component targeted therapies. Here, several strategies of fibroblast targeted therapy are highlighted.

Whole life exposure to low dose cadmium alters diet-induced NAFLD

Nonalcoholic fatty liver disease (NAFLD) is a major global public health concern affecting more than 25% of the world's population. Although obesity and diabetes are major risk factors for NAFLD, they cannot account for all cases, indicating the importance of other factors such as environmental exposures. Cadmium (Cd) exposure is implicated in the development of NAFLD; however, the influence of early life, in utero Cd exposure on the development of diet-induced NAFLD is poorly understood. Therefore, we developed an in vivo, multiple-hit model to study the effect of whole-life, low dose Cd exposure on high fat diet (HFD)-induced NAFLD. Adult male and female C57BL/6 J mice fed normal diets (ND) were exposed to 0, 0.5 or 5 ppm Cd-containing drinking water for 14 weeks before breeding. At weaning, offspring were fed ND or HFD and continued on the same drinking water regimen as their parents for 24 weeks. Cd exposure at different concentrations differentially altered HFD-associated adverse health effects, including liver injury. HFD-induced increased body weight, decreased glucose tolerance. Liver injury and lipid deposition were exacerbated by 5 ppm Cd exposure but attenuated by 0.5 ppm Cd exposure. Further, HFD blunted the response of metallothionein, a major Cd detoxification protein, in mice exposed to 5 ppm Cd but enhanced the response in mice exposed to 0.5 ppm Cd, suggesting a possible mechanism for Cd alteration of HFD-induced NAFLD. These results confirm the multi-hit nature of NAFLD and show whole life, low dose Cd exposure alters HFD-induced NAFLD with outcomes dependent on Cd concentration.

Importance of lymphocyte-stromal cell interactions in autoimmune and inflammatory rheumatic diseases

Interactions between lymphocytes and stromal cells have an important role in immune cell development and responses. During inflammation, stromal cells contribute to inflammation, from induction to chronicity or resolution, through direct cell interactions and through the secretion of pro-inflammatory and anti-inflammatory mediators. Stromal cells are imprinted with tissue-specific phenotypes and contribute to site-specific lymphocyte recruitment. During chronic inflammation, the modified pro-inflammatory microenvironment leads to changes in the stromal cells, which acquire a pathogenic phenotype. At the site of inflammation, infiltrating B cells and T cells interact with stromal cells. These interactions induce a plasma cell-like phenotype in B cells and T cells, associated with secretion of immunoglobulins and inflammatory cytokines, respectively. B cells and T cells also influence the stromal cells, inducing cell proliferation, molecular changes and cytokine production. This positive feedback loop contributes to disease chronicity. This Review describes the importance of these cell interactions in chronic inflammation, with a focus on human disease, using three selected autoimmune and inflammatory diseases: rheumatoid arthritis, psoriatic arthritis (and psoriasis) and systemic lupus erythematosus. Understanding the importance and disease specificity of these interactions could provide new therapeutic options.

Evolving concepts of the pathogenesis of rheumatoid arthritis with focus on the early and late stages

PURPOSE OF REVIEW

To provide an overview of recently published work covering key mechanisms involved in the pathogenesis of rheumatoid arthritis (RA), with focus on the early and late stages.

RECENT FINDINGS

Present understanding of RA pathogenesis has been mainly focused on the inflammatory process at the established phase of the disease, but recent work has shed light on important molecular and cellular mechanisms involved both at the early and late/refractory stages. In early RA, the involvement of anticitrullinated protein antibodies in RA induction has been identified with a critical role of the IL-23/Th17 axis in the control of their pathogenicity. At the late stage, RA may be viewed as a cell-autonomous genetic and epigenetic disease, characterized by altered cell death pathways in synoviocytes after long-term exposure to inflammation. An improved knowledge of these cell-intrinsic altered pathways is the basis for the targeting of pathogenic synoviocytes, as a new therapeutic alternative against resistance to current treatment targeting the immune system.

SUMMARY

We summarize these pathological pathways, and their understanding will facilitate the design of new diagnostic tools and therapeutic strategies combining the targeting of pathogenic synoviocytes with current immune-targeted therapies.

Zinc and Cadmium in the Aetiology and Pathogenesis of Osteoarthritis and Rheumatoid Arthritis

Osteoarthritis (OA) and rheumatoid arthritis (RA) are inflammatory articular conditions with different aetiology, but both result in joint damage. The nutritionally essential metal zinc (Zn²⁺) and the non-essential metal cadmium (Cd²⁺) have roles in these arthritic diseases as effectors of the immune system, inflammation, and metabolism. Despite both metal ions being redox-inert in biology, they affect the redox balance. It has been known for decades that zinc decreases in the blood of RA patients. It is largely unknown, however, whether this change is only a manifestation of an acute phase response in inflammation or relates to altered availability of zinc in tissues and consequently requires changes of zinc in the diet. As a cofactor in over 3000 human proteins and as a signaling ion, zinc affects many pathways relevant for arthritic disease. How it affects the diseases is not just a question of zinc status, but also an issue of mutations in the many proteins that maintain cellular zinc homoeostasis, such as zinc transporters of the ZIP (Zrt-/Irt-like protein) and ZnT families and metallothioneins, and the multiple pathways that change the expression of these proteins. Cadmium interferes with zinc's functions and there is increased uptake under zinc deficiency. Remarkably, cadmium exposure through inhalation is now recognized in the activation of macrophages to a pro-inflammatory state and suggested as a trigger of a specific form of nodular RA. Here, we discuss how these metal ions participate in the genetic, metabolic, and environmental factors that lead to joint destruction. We conclude that both metal ions should be monitored routinely in arthritic disease and that there is untapped potential for prognosis and treatment.

Effect of cadmium on the viability on monolayer cultures of synoviocytes, chondrocytes, and Hoffa: A preliminary study

Osteoarthritis (OA) is the gradual loss of articular cartilage and involves several tissues, such as the synovial membrane, meniscus, ligaments, and adipose tissue known as Hoffa fat pad. There are largely unexplored factors that lead to OA development, such as the impact of exposure to heavy metals like cadmium (Cd) on the viability of cells in the knee joint tissue. The objective of this report was to identify the cell type with the highest susceptibility to Cd toxicity with respect to cell viability and death. Our findings showed that a concentration as low as 3 μM cadmium chloride for 12 h affects the viability of synovial cells, and a concentration of 10 μM affects Hoffa cells. Our results suggest that Cd can affect the viability of synovial and chondral cells primarily. In contrast, Hoffa cells were less susceptible, likely because Cd favors the production of pro-inflammatory cytokines before triggering their death as part of its damage mechanism at the articular level.

Impact of cadmium toxicity on cartilage loss in a 3D in vitro model

Osteoarthritis (OA) is the gradual loss of articular cartilage and decrease in subchondral space. One of the risk factors Exposure to cadmium (Cd) through tobacco smoke has been identified as a major OA risk factor. There are no reports addressing the role of Cd in OA progression at the molecular level. Our findings revealed that Cd can promote the activation of metalloproteinases (MMP1, MMP3, MMP9 y MMP13), affecting the expression of COL2A1 and ACAN, and decreasing the presence of glycosaminoglycans and proteoglycans through an inflammatory response related to IL-1β y a IL-6, as well as oxidative by producing ROS like O₂^-• and H₂O₂. In conclusion, our findings suggest a cytotoxic role of Cd in the articular cartilage, which could affect OA development.

Toxicity of cadmium in musculoskeletal diseases

Epidemiological studies have reported that exposure to toxic metals like cadmium (Cd) may promote the development of musculoskeletal diseases, such as osteoporosis, rheumatoid arthritis (RA), and osteoarthritis (OA), among others. The objective of this review is to summarize the molecular mechanisms of inflammation and oxidative stress activated by Cd at the bone level, particularly in osteoporosis, RA, and OA. Cadmium can increase bone resorption, affect the activity of osteoclasts and calcium (Ca) absorption, and impair kidney function, which favors the development of osteoporosis. In the case of RA, Cd interferes with the activity of antioxidant proteins, like superoxide dismutase (SOD) and catalase (CAT). It also promotes an inflammatory state, inducing the process of citrullination, which affects the proteins of immune response. On the other hand, accumulation of Cd in the tissues and blood of smokers has been related to the development of some musculoskeletal diseases. Therefore, knowing the negative impact of Cd toxicity at the articular level can help understand the damage mechanisms it produces, leading to the development of such diseases.

Neutrophil extracellular traps promote cadmium chloride-induced lung injury in mice

Cadmium (Cd) is a ubiquitous toxic heavy metal derived mainly from industrial processes. In industrialized societies, individuals are exposed to a plethora of sources of Cd pollution. Cd can trigger serious diseases such as rheumatoid arthritis (RA) and chronic obstructive pulmonary disease (COPD) by the over-activating immune system. As an effector mechanism in innate immunity, neutrophil extracellular traps (NETs) not only play an important role in defending against infection but also lead to tissue damage. However, the role of NETs in Cd-induced lung damage process has not been previously studied. In this study, we aimed to investigate the potential effects of Cd-induced NETs on lung injury in vivo and further to clarify the molecular mechanisms of Cd-induced NETs formation. In vivo, Cd treatment destroyed the structural integrity of lung tissue and significantly increased the levels of NETs in the bronchoalveolar lavage fluid (BALF). The known NETs inhibitor DNase I ameliorated pathologic changes and significantly decreased levels of NETs in BALF, which suggesting the curial role of NETs in Cd-induced lung injury. Further investigation showed that Cd could significantly trigger NETs formation, which is composed of DNA backbone decorated with histones (H3) and neutrophils elastase (NE). The inhibitors of NADPH oxidase, ERK1/2 and p38 MAPK-signaling pathways significantly reduced the formation of NETs, and western blotting analysis also showed that Cd significantly increased the phosphorylation of p38 and ERK1/2 signaling pathways. Above results confirmed that NADPH oxidase, ERK1/2 and p38 MAPK-signaling pathways were related to Cd-induced NETs formation. In conclusion, NETs was involved in Cd-induced lung injury, and the mechanisms of Cd-induced NETs formation was via activating NADPH oxidase, ERK1/2 and p38 MAPK-signaling pathways, which might provide a new perspective in Cd-induced lung injury.

Prevalence of rheumatoid arthritis in relation to serum cadmium concentrations: cross-sectional study using Korean National Health and Nutrition Examination Survey (KNHANES) data

OBJECTIVES

It has been suggested that exposure to heavy metal cadmium (Cd) may contribute to a high risk of developing rheumatoid arthritis (RA). This study was to investigate the association of RA prevalence and serum concentrations of Cd and other heavy metals through large survey data analysis.

DESIGN

A retrospective cross-sectional survey study.

SETTING

Large population survey in Korea.

PARTICIPANTS

53 829 subjects participated in Korean National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2013.

INTERVENTIONS

Heavy metals were measured in different time periods of the survey programme which resulted in three different data sets for analysis: Cd, mercury (Hg) and lead (Pb) from 2008 to 2012 survey; serum manganese (Mn) and urine arsenic (As) from 2008 to 2009 survey; and serum zinc (Zn) from 2010 survey. RA prevalence and its associations with serum heavy metals were analysed using a general linear/logistic regression model of complex sample design.

RESULTS

Serum Cd was elevated in patients with RA (RA vs control: 1.30±0.07 µg/L vs 1.17±0.01 µg/L, p<0.01). There were no significant differences in urine levels of As or serum levels of Pb, Hg, Mn or Zn between patients with RA and controls. OR (95% CI) of RA prevalence according to 1 µg/L increase of serum Cd level was 1.28(95% CI 1.03 to 1.61). Prevalence of RA in women was increased with increasing quartiles of Cd levels, with a 19-fold difference in female RA prevalence between individuals in the lowest quartile of serum Cd level and those in the highest quartile (0.18% vs 3.42%). Cubic spline curve of prevalence OR showed increased risk of RA according to increased serum Cd level. Increased risk of RA in men was not observed with increased serum Cd levels.

CONCLUSION

There was an increased prevalence of RA in females associated with increased serum levels of Cd in the Korean population.

Live-stream characterization of cadmium-induced cell death using visible CdTe-QDs

Characterization of cell death currently requires the use of indirect markers, which has largely limited the ability to monitor cell death processes inside the cell. Here, we introduce a new method for the characterization of cell death mechanisms using cadmium telluride quantum dots (CdTe-QDs). Using visible CdTe-QDs with mesenchymal cells (e.g. synoviocytes), live-stream imaging allowed for visualization of cadmium-induced cell death, combining characteristics of apoptosis and autophagy. Initially, similar anti-proliferative effect was observed between 10 µg/ml Cd²⁺ and CdTe-QDs at 24 h (cell index/cell density ratio decreased from 0.6 to −16.6, p < 0.05) using techniques that do not require the capacity of CdTe-QDs. Apoptosis was confirmed by the quantification of morphological parameters (reduced surface area, increased cell thickness) and positive labeling with annexin V. Autophagy was confirmed by monodansylcadaverine staining, identifying similar autophagic vacuoles with both Cd²⁺ and CdTe-QD. However, QD imaging allowed for visualization of cadmium elements inside cell structures and their kinetic changes leading to cell death. Cell death characteristics were similar in inflammatory and non-inflammatory environment but were induced up to 4 h earlier in the former. Therefore, live-stream imaging of a visible cytotoxic agent has useful applications not currently possible with indirect methods, including chronological monitoring of cell death.

Differential effects of TNF-α and IL-1β on the control of metal metabolism and cadmium-induced cell death in chronic inflammation

OBJECTIVE

Interleukin-1-beta (IL-1β) and tumour necrosis factor-alpha (TNF-α) are both monocyte-derived cytokines. Both cytokines have been previously described to exert a role in rheumatoid arthritis (RA) pathogenesis synergizing with other pro-inflammatory mediators, such as interleukin-17 (IL-17) on target cells, for the perpetuation of the inflammatory response (e.g. IL-6 production). In the context of experimental RA, Cd addition has an anti-proliferative and anti-inflammatory effect when associated to IL-17/TNF-α stimulation, due to its accumulation in synoviocytes. The aim of this work was to evaluate if IL-1β interaction with IL-17 also contributes to metal-import mechanisms and its effects on cell viability and inflammation.

METHODS

IL-17 and IL-1β were added to synoviocyte cultures with or without exogenous Cd addition (0.1 ppm, 0.89 μM). IL-6 production, Cd import kinetics, gene expression of ZIP-8 importer and metallothioneins (MTs) and cell viability were evaluated by ELISA, inductively-coupled mass spectrometry (ICP-MS), q-RT-PCR and viability assays (neutral red and annexin V) respectively.

RESULTS

IL-17 and IL-1β acted in synergy on synoviocytes to induce IL-6 production similarly to the IL-17/TNF-α combination. Metal import was lower with IL17/ IL-1β in comparison to IL-17/TNF-α exposed-synoviocytes, as the expression of ZIP-8 and MT-1F was less induced. Monocyte and PBMCs exposure to Cd resulted in a reduced production of IL-1β and an increased production of TNF-α and this result was confirmed in co-cultures of synoviocytes and PBMCs. The IL-17/IL-1β combination with Cd slightly reduced cell viability in comparison to the IL-17/TNF-α combination and resulted in a strong induction of IL-6 production.

CONCLUSION

IL-17/TNF-α combination but not IL-17/IL-1β combination mainly drives the accumulation of Cd in synoviocytes and its effects on cell viability and inflammation.

The Tumor-Like Phenotype of Rheumatoid Synovium: Molecular Profiling and Prospects for Precision Medicine

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by destructive hyperplasia of the synovium. Fibroblast-like synoviocytes (FLS) are a major component of synovial pannus and actively participate in the pathologic progression of RA. How rheumatoid FLS acquire and sustain such a uniquely aggressive phenotype remains poorly understood. We describe the current state of knowledge of the molecular alterations in rheumatoid FLS at the genomic, epigenomic, transcriptomic, proteomic, and metabolomic levels, which offers a means to reconstruct the pathways leading to rheumatoid pannus. Such data provide new pathologic insight and suggest means to more sensitively assess disease activity and response to therapy, as well as support new avenues for therapeutic development.

Ilizarov external fixation versus plate internal fixation in the treatment of end-stage ankle arthritis: decision analysis of clinical parameters

The purpose of this study was to evaluate the effect of Ilizarov external fixation (IEF) and plate internal fixation (PIF) in the treatment of end-stage ankle arthritis on pain relieving and function improvement. The study cohort consisted of 59 patients with end-stage ankle arthritis underwent ankle arthrodesis with IEF or PIF between June 2011 and June 2015. Standard radiographs and computed tomography (CT) scans were obtained before surgery and during the follow-up. Functional assessments were performed using Foot and Ankle pain score of American Orthopedics Foot and Ankle Society (AOFAS) and Visual Analogue Scale (VAS). The average AOFAS scores in both IEF group and PIF groups increased significantly after operation, from 45.5 ± 6.3 to 84.8 ± 4.9 and from 45.9 ± 6.6 to 86.6 ± 5.4, respectively. The average VAS scores in both groups decreased significantly after operation, from 8.4 ± 1.9 to 2.5 ± 0.6 and from 8.2 ± 1.5 to 2.3 ± 0.7, respectively. Nevertheless, there was no significant difference for preoperative or postoperative AOFAS and VAS scores between the two groups. The IEF would result in comparable postoperative functional recovery and pain relieving to PIF and may be an effective substitute to PIF in the treatment of end-stage ankle arthritis.

Regulatory effects of zinc on cadmium-induced cytotoxicity in chronic inflammation

OBJECTIVES

Zinc (Zn) has major effects on immune system activation while Cadmium (Cd) has anti-inflammatory and anti-proliferative effects in several chronic inflammatory contexts. The aim of this work was to investigate by which mechanisms Zn could compete with Cd and eventually counteract its deleterious effects. Rheumatoid arthritis (RA) synoviocytes exposed to cytokines were used as a model of chronic inflammation; osteoarthritis (OA) synoviocytes were used as control.

METHODS

Cell/medium fractionation constants were analyzed for different metals by inductively-coupled-plasma mass-spectrometry by comparison to the 70Zn spike. Interleukin-17 (IL-17) and tumor necrosis factor-alpha (TNF-α) were used to mimic inflammation. Gene expression of ZIP-8 importer, metallothioneins-1 (MT-1s) and the ratio between metalloprotease-3 and the tissue inhibitor of metalloproteinases (MMP-3)/TIMP-1) were evaluated after pre-exposure to cytokines and Cd, with or without the addition of exogenous Zn (0.9 ppm). Cell viability was measured by neutral red assay and IL-6 production by ELISA.

RESULTS

Synoviocytes selectively absorbed and retained Cd in comparison to Zn. Metal import increased with IL-17/TNF-α exposure, through the enhanced ZIP-8 expression. Zn did not modify ZIP-8 expression, while Cd reduced it (p<0.05). Zn induced a reduction of Cd-induced MT-1s expression, in particular of MT-1X (3-fold), and subsequently the final intra-cellular content of Cd. By reducing Cd accumulation in cells, Zn reversed Cd anti-proliferative and anti-inflammatory effects but preserved the low MMP-3/TIMP-1 ratio induced by Cd, which was enhanced by inflammatory conditions.

CONCLUSION

Zinc counteracts the deleterious effect of Cd by reducing its import and accumulation in the cell, without the reactivation of destructive pathways such as MMPs.