Infliximab therapy decreases the expression of serum and faecal miR-126 and miR-20a in paediatric Crohn's disease: A pilot study.

AIM: We aimed to evaluate the serum and faecal expression of miR-126 and miR-20a in children with Crohn's disease (CD) during infliximab (IFX) therapy. METHODS: In this prospective observational study, serum and faeces from CD patients were collected before IFX therapy (T0), after induction (T1) and after 6 months from IFX (T2). IFX levels were determined by Enzyme-linked immunosorbent assay at T1 and T2. miRNAs were profiled through Real-Time RT-PCR. The activity of disease was evaluated through the Paediatric Crohn's disease activity index (PCDAI), serum C-reactive protein (CRP) and faecal calprotectin. RESULTS: Nine CD children were enrolled. Serum and faecal miR-126 and miR-20a levels were higher at T0 and showed a time-dependent decrease, being significantly down-regulated after IFX treatment at T2. Specifically, IFX levels recorded at T1 and T2 negatively correlated with the serum and faecal expression of miR-126 and miR-20a. Serum and faecal changes of miR-126 and miR20-a were positively associated with the decrease of the inflammatory marker CRP and PDCAI at all time points. CONCLUSION: In children with CD, IFX therapy decreases the expression of serum and faecal miR-126 and miR-20a, suggesting an involvement of these two miRNAs in the action of the drug.

Increased expression of CB2 receptor in the intestinal biopsies of children with inflammatory bowel disease.

OBJECTIVES: The Cannabinoid Receptor type 2 (CB2) is involved in inflammation and immune cell modulation. In previous studies, we demonstrated the association between the CNR2 rs35761398 polymorphism and the risk for pediatric inflammatory bowel disease (IBD). In this study, we analyzed the intestinal biopsies from Crohn disease (CD) and ulcerative colitis (UC) pediatric patients at the diagnosis to evaluate the expression of CB2 and several factors associated with IBD inflammatory pathways. METHODS: We enrolled five patients with CD, five with UC, and five controls (CTR). We analyzed ileum and rectum biopsies from patients of each group evaluating the expression of CB2, Toll-like receptor 4, interleukin-6, and interleukin-1ß by western blot and immunofluorescence. RESULTS: Western blot analysis showed a significant increase of CB2 in the CD ileum and in the UC rectum biopsies and an increase of TLR4 in the UC rectum. We also observed a significant over-expression of the IL-6 in UC rectum. The immunofluorescence analysis confirmed western blot data, showing also a T-lymphocytes infiltration colocalized with CB2 expression in the CD ileum and UC rectum. CONCLUSIONS: Our results show an upregulation of CB2 in pediatric IBD, which might have implications for drug discovery. IMPACT: The Cannabinoid Receptor type 2 (CB2) is involved in the inflammation and modulation of the immune response in pediatric inflammatory bowel disease (IBD). CB2 receptor is more expressed in the inflamed intestine of pediatric IBD patients. CB2 could be used as a potential therapeutic target to reduce IBD-related inflammatory state in childhood.

Effects of CB2 and TRPV1 Stimulation on Osteoclast Overactivity Induced by Iron in Pediatric Inflammatory Bowel Disease.

BACKGROUND: The reduction of bone mineral density and osteoporosis have high impacts on the health of patients with inflammatory bowel diseases (IBD). We have previously shown that a dysregulated iron metabolism occurs in IBD and leads to a decrease in circulating iron concentration and excessive intracellular sequestration of iron. Studies suggest that iron overload significantly affects the bone, accelerating osteoclast (OC) differentiation and activation, promoting bone resorption. Moreover, we demonstrated that iron overload causes OC overactivity. The cannabinoid receptor type 2 (CB2) and the transient receptor potential vanilloid type-1 (TRPV1) are potential therapeutic targets for bone diseases. The aim of this study was to evaluate the roles of CB2 and TRPV1 receptors and of iron in the development of osteoporosis in pediatric IBD. METHODS: We differentiated OCs from peripheral blood mononuclear cells of patients with IBD and healthy donors and evaluated CB2 and TRPV1 receptor expression; OC activity, and iron metabolism by Western blot, TRAP assays, bone resorption assays, and iron assays. Moreover, we analyzed the effects of the pharmacological modulation of CB2 and TRPV1 receptors on OC activity and on the iron metabolism. RESULTS: We confirmed the well-known roles of CB2 and TRPV1 receptors in bone metabolism and suggested that their stimulation can reduce the OC overactivity induced by iron, providing new insights into the pathogenesis of pediatric IBD-related bone resorption. CONCLUSIONS: Stimulation of CB2 and TRPV1 could reduce IBD-related osteoporosis due to their direct effects on OC activity and to modulating the iron metabolism.

In this study, we provide new insights into the pathogenesis of inflammatory bowel disease (IBD)­related bone resorption, suggesting a role for iron. Cannabinoid receptor type 2 and transient receptor potential vanilloid type-1 stimulation could reduce IBD-related osteoporosis, directly affecting osteoclast activity and modulating iron metabolism.

Effects of CB2 Receptor Modulation on Macrophage Polarization in Pediatric Celiac Disease.

Celiac Disease (CD) represents an autoimmune disorder triggered by the exposure to gluten in genetically susceptible individuals. Recent studies suggest the involvement of macrophages in CD pathogenesis. Macrophages are immune cells, present as pro-inflammatory classically activated macrophages (M1) or as anti-inflammatory alternatively activated macrophages (M2). The Cannabinoid Receptor 2 (CB2) has important anti-inflammatory and immunoregulatory properties. We previously demonstrated that a common CB2 functional variant, Q63R, causing CB2 reduced function, is associated with several inflammatory and autoimmune diseases The first aim of this study was to investigate the phenotype of macrophages isolated from peripheral blood of CD patients and CB2 expression. The second aim was to evaluate the effects of CB2 pharmacological modulation on CD macrophage polarization. Moreover, by an in vitro model of "immunocompetent gut" we investigated the role of CD macrophages in inducing intestinal barrier damage and the possibility to restore its functionality modulating their polarization. We found an increased expression of M1 macrophages and a CB2 reduced expression. We also demonstrated CD M1 macrophages in inducing the typical mucosal barrier damage of CD. CB2 stimulation switches macrophage polarization towards the anti-inflammatory M2 phenotype thus reducing inflammation but also limiting the epithelial dysfunction. Therefore, we suggest CB2 receptor as a possible novel therapeutic target for CD by regulating macrophages polarization and by preventing mucosal barrier damage.