Depression is a global health problem that requires an early and accurate diagnosis to ensure quick access to appropriate treatment. Among multiple psychopathological paths, recent attention has focused on analysing the brain–gut–microbiota axis. The intestinal barrier plays a key role, and dysfunctions occurring at this level have implications for mental health. The aim of the present study was to investigate the role of intestinal permeability biomarkers, i.e., calprotectin, zonulin, lipopolysaccharide-binding protein (LBP) and intestinal fatty acid-binding protein (I-FAB), in relation to depression in patients with inflammatory bowel disease (IBD). This is the first study of this kind taking place in Romania, Eastern Europe, with an emphasis on patients with Crohn’s disease and ulcerative colitis. The correlations identified between depression and calprotectin and depression and LBP have the potential to shed light on the process of rapid diagnosis of depression with the help of biomarkers. Since depression is correlated with a decrease in the quality of life in patients with IBD, the need for access to appropriate treatments must be urgent.

Background and Objectives: Calprotectin is a marker for intestinal inflammation. Recent research suggests a link between inflammation and depression. This study assessed the association between the levels of calprotectin in patients from South-Eastern Europe and the severity of depression, anxiety, and quality of life. Materials and Methods: This cross-sectional study included 30 confirmed patients with Crohn’s disease (CD) and ulcerative colitis (UC) who were assessed using clinical interviews for determining the severities of mental disorders (i.e., depression severity—PHQ-9, anxiety—GAD-7) and the quality of life (EQ-5D). Stool samples were collected from all participants for measuring their levels of calprotectin. Results: The level of calprotectin is correlated with PHQ-9 (ρ = 0.416, p = 0.022) and EQ-5D (ρ = −0.304, p = 0.033) but not with GAD 7 (ρ = 0.059, p = 0.379). Calprotectin levels in patients with mild, moderate, and moderately severe depression were significantly higher than in patients with minimal depression (198 µg/g vs. 66,9 µg/g, p = 0.04). Calprotectin level was corelated with the following depressive symptoms: autolytic ideation (ρ = 0.557, p = 0.001), fatigue (ρ = 0.514, p = 0.002), slow movement (ρ = 0.490, p = 0.003), and sleep disorders (ρ = 0.403, p = 0.014). Calprotectin was an independent predictor of depression with an odds ratio of 1.01 (95%: 1.002–1.03, p < 0.01). An ROC analysis showed that a level of calprotectin of 131 µg/g or higher has a sensitivity of 82%, a specificity of 61%, and an accuracy of 70% for predicting depression. In this study, no significant correlations were found between calprotectin level and anxiety. Conclusions: Calprotectin levels are associated with the severity of depression, and checking for a calprotectin level of 131 µg/g or higher may be a potential accessible screening test for depression in patients with inflammatory bowel disease.

Background and Aims: MicroRNAs (miR) have altered expression in multiple autoimmune disorders including inflammatory bowel disease. The aim of the study was to assess the tissue and circulating miR-31, miR-200b, and miR-200c expression levels as potential biomarkers for intestinal disease activity in patients with Crohn’s disease (CD). Methods: The study included 45 patients with histopathological confirmed CD and active disease (defined as fecal calprotectin >50 μg/g and Simple Endoscopic Score (SES) of CD >3), and 21 subjects as controls for the validation cohort. Demographic and clinical data, biomarkers (fecal calprotectin), endoscopy data, the expression levels of miR-31, miR-200b, and miR-200c in tissue and serum were assessed (by RT-PCR). Receiver operating characteristic analysis was performed to assess the miR-31, miR-200b, and miR-200c expression levels as potential biomarkers for active CD. Results: Mean fecal calprotectin was 1540±890 μg/g. Mean SES-CD was 8.9±4.2. Tissue and circulating miR- 31 were significantly correlated with fecal calprotectin (r=0.81, r=0.83, p<0.01) and with SES-CD (r=0.82, r=0.79, p<0.01). The expression level of miR-31 was significantly upregulated in CD tissue cases compared to the control tissue samples (6.24±1.57 vs. 3.70±1.44; p <0.01). Similarly, serum miR-31 expression levels in CD patients were significantly upregulated compared to the control serum samples (0.78±0.42 vs. -2.07±1.00; p<0.01). The expression levels of tissue miR-200b and miR-200c were significantly upregulated in CD tissue cases compared to the control tissue samples (-5.25±0.93 vs. -4.69±0.80, p=0.03 for miR-200b, and -0.86±0.96 vs. 0.39±0.66, p<0.01 for miR-200c). Similarly, serum miR-200b and miR-200c expression levels in CD patients were significantly upregulated compared to the control serum samples (p < 0.05). Receiver operating characteristic analysis revealed that the expression levels of the selected miRNAs could help to discriminate active CD patients from healthy controls with very good specificity and sensitivity. Conclusions: Tissue and circulating miR-31, miR-200b, and miR-200c reflect disease activity in CD patients and can be used as biomarkers for active disease.