Arthritis has a high prevalence globally and includes over 100 types; the most common of which are rheumatoid arthritis (RA), osteoarthritis (OA), psoriatic arthritis and inflammatory arthritis. All types of arthritis share common features of the disease, including monocyte infiltration, inflammation, synovial swelling, pannus formation; stiffness in the joints and articular cartilage destruction.

The exact etiology of arthritis remains unclear and no cure exists. Anti-inflammatory drugs are common in the treatment of arthritis but are with significant side effects, such as gastric bleeding; an increased risk for heart attacks and other cardiovascular problems. Novel modes of therapy and additional prognostic biomarkers are urgently needed for these patients.

The pathogenesis of arthritis

Therefore in response to the call for papers, so they received many submissions from all over the world. After an initial screening; they selected 20 articles that are appropriate for this Special Issue. But all manuscripts underwent a very rigorous peer-review process. The papers included in this issue can broadly organized into three main categories; the pathogenesis of arthritis, new biomarkers and novel strategies in the treatment of arthritis.

The involvement of growth factors, inflammatory cytokines and differential miRNA expression in synovial tissue, articular cartilage and subchondral bone during the onset and progression of OA has been summarized by two research groups , while another research team has reviewed how the Epstein–Barr virus (EBV) is able to induce the onset of RA in predisposed shared epitope (SE)-positive individuals, by promoting entry of B-cells through direct contact between SE and gp42 in the entry complex.

An interesting article from Polish researchers reviews the evidence on the role of mesenchymal stromal cells in the pathogenesis of spondyloarthropathies (SpA); so discusses the potential use of stem cells in regenerative processes and the treatment of inflammatory changes in articular structures. New biomarkers. Dudics et al. examined the miRNA expression profiles of immune cells from arthritic Lewis rats and arthritic rats treated with celastrol; a natural triterpenoid.

Response in autoimmune arthritis

Therefore their results indicate that several miRNAs may serve as novel biomarkers of disease activity and therapeutic response in autoimmune arthritis. Another article, by Chen et al., has explored the differential expression of novel miRNAs in RA osteoblasts.

The findings suggest that certain candidate genes may help in the evaluation of therapies targeting chemotaxis and neovascularization in an effort to control joint destruction in RA. In conclusion, the editorial, the twenty articles published in the Special Issue Research of Pathogenesis and Novel Therapeutics in Arthritis 2019 are summarized and discussed as part of the global picture of the current understanding of arthritis.