Synovial fluid survivin and NETs as independent biomarkers in rheumatoid arthritis.

OBJECTIVES: To quantify survivin and NETs in synovial fluid (SF) of patients with rheumatoid arthritis (RA) and osteoarthritis (OA), and to assess whether there is a correlation of the quantifications with the exclusion of OA diagnosis and the activity of RA. METHODS: We performed a cross-sectional, observational study, in which 32 patients with RA and 16 with OA were included. Clinical and laboratory data were obtained, in addition to routine analysis of SF and the measurement of SF survivin and NETs. RA activity was assessed by DAS28. RESULTS: Concentrations of survivin (median, 356.9 vs. 49.9 pg/mL; p=0.0006) and NETs (median, 100.7 vs. 49.7 ng/mL; p=0.004) were elevated in the SF of the RA group compared to those of the OA group. ROC curves showed the following values for measurements of survivin and NETs: AUC of 79% and 75% respectively, with sensitivity of 75% and specificity of 78% for both. There was no correlation between survivin and NETs values for both groups, but we found association between SF survivin and serum ACPA for RA patients. CONCLUSIONS: We found an independent association between levels of survivin and NETs in SF with the exclusion of OA diagnosis, but not with RA activity. There was no correlation between survivin and NETs in SF, because we suppose that resistance to apoptosis, mediated by survivin, and NETosis are independently related to the pathophysiology of RA.

TGF-ß signalling defect is linked to low CD39 expression on regulatory T cells and methotrexate resistance in rheumatoid arthritis.

Rheumatoid arthritis (RA) is an autoimmune arthropathy characterized by chronic articular inflammation. Methotrexate (MTX) remains the first-line therapy for RA and its anti-inflammatory effect is associated with the maintenance of high levels of extracellular adenosine (ADO). Nonetheless, up to 40% of RA patients are resistant to MTX treatment and this is linked to a reduction of CD39 expression, an ectoenzyme involved in the generation of extracellular ADO by ATP metabolism, on circulating regulatory T cells (Tregs). However, the mechanism mediating the reduction of CD39 expression on Tregs is unknown. Here we demonstrated that the impairment in TGF-ß signalling lead to the reduction of CD39 expression on Tregs that accounts for MTX resistance. TGF-ß increases CD39 expression on Tregs via the activation of TGFBRII/TGFBRI, SMAD2 and the transcription factor CREB, which is activated in a p38-dependent manner and induces CD39 expression by promoting ENTPD1 gene transcription. Importantly, unresponsive patients to MTX (UR-MTX) show reduced expression of TGFBR2 and CREB1 and decreased levels of p-SMAD2 and p-CREB in Tregs compared to MTX-responsive patients (R-MTX). Furthermore, RA patients carrying at least one mutant allele for rs1431131 (AT or AA) of the TGFBR2 gene are significantly (p = 0.0006) associated with UR-MTX. Therefore, we have uncovered a molecular mechanism for the reduced CD39 expression on Tregs, and revealed potential targets for therapeutic intervention for MTX resistance.

Macrophage-derived human resistin promotes perivascular adipose tissue dysfunction in experimental inflammatory arthritis.

Cardiovascular disease (CVD) is the leading cause of death in rheumatoid arthritis (RA). Resistin is an adipokine that induces adipose tissue inflammation and activation of monocytes/macrophages via adenylate cyclase-associated protein-1 (CAP1). Resistin levels are increased in RA and might cause perivascular adipose tissue (PVAT) dysfunction, leading to vascular damage and CVD. This study aimed to investigate the role of resistin in promoting PVAT dysfunction by increasing local macrophage and inflammatory cytokines content in antigen-induced arthritis (AIA). Resistin pharmacological effects were assessed by using C57Bl/6J wild-type (WT) mice, humanized resistin mice expressing human resistin in monocytes-macrophages (hRTN+/-/-), and resistin knockout mice (RTN-/-) with AIA and respective controls. We investigated AIA disease activity and functional, cellular, and molecular parameters of the PVAT. Resistin did not contribute to AIA disease activity and its concentrations were augmented in the PVAT and plasma of WT AIA and hRTN+/-/- AIA animals. In vitro exposure of murine arteries to resistin impaired vascular function by decreasing the anti-contractile effect of PVAT. WT AIA mice and hRTN+/-/- AIA mice exhibited PVAT dysfunction and knockdown of resistin prevented it. Macrophage-derived cytokines, markers of types 1 and 2 macrophages, and CAP1 expression were increased in the PVAT of resistin humanized mice with AIA, but not in knockout mice for resistin. This study reveals that macrophage-derived resistin promotes PVAT inflammation and dysfunction regardless of AIA disease activity. Resistin might represent a translational target to reduce RA-driven vascular dysfunction and CVD.

A single cell atlas of frozen shoulder capsule identifies features associated with inflammatory fibrosis resolution.

Frozen shoulder is a spontaneously self-resolving chronic inflammatory fibrotic human disease, which distinguishes the condition from most fibrotic diseases that are progressive and irreversible. Using single-cell analysis, we identify pro-inflammatory MERTKlowCD48+ macrophages and MERTK + LYVE1 + MRC1+ macrophages enriched for negative regulators of inflammation which co-exist in frozen shoulder capsule tissues. Micro-cultures of patient-derived cells identify integrin-mediated cell-matrix interactions between MERTK+ macrophages and pro-resolving DKK3+ and POSTN+ fibroblasts, suggesting that matrix remodelling plays a role in frozen shoulder resolution. Cross-tissue analysis reveals a shared gene expression cassette between shoulder capsule MERTK+ macrophages and a respective population enriched in synovial tissues of rheumatoid arthritis patients in disease remission, supporting the concept that MERTK+ macrophages mediate resolution of inflammation and fibrosis. Single-cell transcriptomic profiling and spatial analysis of human foetal shoulder tissues identify MERTK + LYVE1 + MRC1+ macrophages and DKK3+ and POSTN+ fibroblast populations analogous to those in frozen shoulder, suggesting that the template to resolve fibrosis is established during shoulder development. Crosstalk between MerTK+ macrophages and pro-resolving DKK3+ and POSTN+ fibroblasts could facilitate resolution of frozen shoulder, providing a basis for potential therapeutic resolution of persistent fibrotic diseases.

The ethics of AI in health care: A mapping review.

This article presents a mapping review of the literature concerning the ethics of artificial intelligence (AI) in health care. The goal of this review is to summarise current debates and identify open questions for future research. Five literature databases were searched to support the following research question: how can the primary ethical risks presented by AI-health be categorised, and what issues must policymakers, regulators and developers consider in order to be 'ethically mindful? A series of screening stages were carried out-for example, removing articles that focused on digital health in general (e.g. data sharing, data access, data privacy, surveillance/nudging, consent, ownership of health data, evidence of efficacy)-yielding a total of 156 papers that were included in the review. We find that ethical issues can be (a) epistemic, related to misguided, inconclusive or inscrutable evidence; (b) normative, related to unfair outcomes and transformative effectives; or (c) related to traceability. We further find that these ethical issues arise at six levels of abstraction: individual, interpersonal, group, institutional, and societal or sectoral. Finally, we outline a number of considerations for policymakers and regulators, mapping these to existing literature, and categorising each as epistemic, normative or traceability-related and at the relevant level of abstraction. Our goal is to inform policymakers, regulators and developers of what they must consider if they are to enable health and care systems to capitalise on the dual advantage of ethical AI; maximising the opportunities to cut costs, improve care, and improve the efficiency of health and care systems, whilst proactively avoiding the potential harms. We argue that if action is not swiftly taken in this regard, a new 'AI winter' could occur due to chilling effects related to a loss of public trust in the benefits of AI for health care.