Inflammatory bowel diseases (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), are complex chronic inflammatory conditions of the gastrointestinal tract that are driven by perturbed cytokine pathways. Anti-tumor necrosis factor-α (TNF) antibodies are a mainstay therapeutic approach for IBD. However, up to 40% of patients are non-responsive to anti-TNF agents, and identifying alternative therapeutic targets is a priority. Here we show that expression of the cytokine Oncostatin M (OSM) and its receptor (OSMR) is increased in the inflamed intestine of IBD patients compared to healthy controls, and correlates closely with histopathological disease severity. OSMR is expressed in non-hematopoietic, non-epithelial intestinal stromal cells, which respond to OSM by producing various pro-inflammatory molecules including interleukin-6 (IL-6), the leukocyte adhesion factor ICAM-1, and chemokines that attract neutrophils, monocytes, and T cells. In an animal model of anti-TNF resistant intestinal inflammation, genetic deletion or pharmacological blockade of OSM significantly attenuates colitis. Furthermore, high pre-treatment OSM expression is strongly associated with failure of anti-TNF therapy based on analysis of over 200 IBD patients, including two cohorts from phase 3 clinical trials of infliximab and golimumab. OSM is thus a potential biomarker and therapeutic target for IBD, with particular relevance for anti-TNF resistant patients.

In the version of this article initially published, there were two typographical errors in the Abstract. The unnecessary 'h' in the line "Furthermore, h according to….. " has been deleted. The line "OSM is thus a potential biomarker of and therapeutic target for IBD,…. " was changed to read "OSM is thus a potential biomarker and therapeutic target for IBD…". These errors have been corrected in the HTML and PDF versions of the article. A coding error that inadvertently resulted in incorrect ordering of the authors in the HTML version was also corrected.

Objective: Pre-clinical and uncontrolled studies in patients with systemic lupus erythematosus (SLE) showed that mesenchymal stromal cells (MSCs) have a potential therapeutic role in refractory cases. The optimal therapeutic strategy in these patients remain to be elucidated. Our aim was to test the hypothesis that repeated administrations of 1×10 6 /kg body weight of allogenic MSCs, that is a significantly lower dosage with respect to the fixed 1×10 6 MSC used in animal models, can be effective in improving the clinical course of a murine SLE model. Methods: Bone marrow derived MSCs were obtained from 12-week-old C57BL/6J mice. Seventy-five 8 weeks old female NZ mice were randomly assigned to receive via caudal vein the following alternative treatments: 1) single infusion of 10 6 MSCs/kg body weight at 18 weeks of age (NZs18) or at at 22 weeks of age (NZs22); 2) multiple monthly infusions of 10 6 MSCs/kg body weight starting at 18 weeks of age (NZM18) or at 22 weeks of age (NZM22); 3) saline infusions (NZc) Fifteen 8 weeks old C57BL/6J mice (Envigo, Huntingdon, UK) were used as untreated controls (C). Weekly, body weight was recorded and twenty-four hour urines were collected by metabolic cages for each animal; proteinuria was detected by dipstick analysis. At sacrifice, peripheral blood samples were collected from mice and anti-dsDNA antibodies were detected by enzyme immunoassorbent assay (ELISA) method using commercial kits. At sacrifice, kidneys were analyzed for histopathology and immunohistochemical analysis for B220, CD4, MPO, CD4 ＋ Foxp3, F40/80 infiltration was performed. Results: Proteinuria occurrence was delayed NZS and NZM mice, no differences were observed in anti-dsDNA autoantibody titer among the groups at the different time-points; at 36 weeks, no significant differences were observed in term of nephritis scores. Inflammatory cells deposition (MPO and F4/80 positive cells) in NZM was significantly higher than in NZ and NZS. An overexpression of B lymphocytes (B220) was found in NZM while T regulatory cells (CD4 ＋ Foxp3＋ cells) were reduced in both NZS and NZM with respect to NZc. Conclusions: Overall, our study failed to show a positive effect of a treatment with murine MSCs in this model and, for some aspects, even deleterious results seem to be observed.

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