Razvan Arsenescu

Adipose tissue immune response: novel triggers and consequences for chronic inflammatory conditions.

Adipose tissue inflammation mediates the association between excessive body fat accumulation and several chronic inflammatory diseases. A high prevalence of obesity-associated adipose tissue inflammation was observed not only in patients with cardiovascular conditions but also in patients with inflammatory bowel diseases, abdominal aortic aneurysm, or cardiorenal syndrome. In addition to excessive caloric intake, other triggers promote visceral adipose tissue inflammation followed by chronic, low-grade systemic inflammation. The infiltration and accumulation of immune cells in the inflamed and hypertrophied adipose tissue promote the production of inflammatory cytokines, contributing to target organ damages. This comorbidity seems to delimit subgroups of individuals with systemic adipose tissue inflammation and more severe chronic inflammatory diseases that are refractory to conventional treatment. This review highlights the association between adipose tissue immune response and the pathophysiology of visceral adiposity-related chronic inflammatory diseases, while suggesting several new therapeutic strategies.

Signature biomarkers in Crohn's disease: toward a molecular classification.

In an effort to develop a molecular classification scheme for Crohns disease (CD), mucosal biopsies from 69 CD patients and 28 normal controls were analyzed for expression of the RelA subunit of nuclear factor (NF)-κB, A20 (a negative regulator of NF-κB), polymeric immunoglobulin receptor (pIgR), tumor necrosis factor (TNF), and interleukin (IL)-8. Principal component analysis was used to classify individuals into three subsets based on patterns of biomarker expression. Set 1 included normal subjects and CD patients with mild disease and good responses to therapy, thus defining “normal” biomarker expression. CD patients in set 2, characterized by low expression of all five biomarkers, had moderate to severe disease and poor responses to immunosuppressive and anti-TNF therapy. Patients in set 3, characterized by low expression of RelA, A20, and pIgR, normal TNF and elevated IL-8, had acute inflammation that responded well to therapy. Classification of CD patients by these biomarkers may predict disease behavior and responses to therapy.

Use of probe-based confocal laser endomicroscopy (pCLE) in gastrointestinal applications. A consensus report based on clinical evidence

Background Probe-based confocal laser endomicroscopy (pCLE) provides microscopic imaging during an endoscopic procedure. Its introduction as a standard modality in gastroenterology has brought significant progress in management strategies, affecting many aspects of clinical care and requiring standardisation of practice and training. Objective This study aimed to provide guidance on the standardisation of its practice and training in Barrett’s oesophagus, biliary strictures, colorectal lesions and inflammatory bowel diseases. Methods Initial statements were developed by five group leaders, based on the available clinical evidence. These statements were then voted and edited by the 26 participants, using a modified Delphi approach. After two rounds of votes, statements were validated if the threshold of agreement was higher than 75%. Results Twenty-six experts participated and, among a total of 77 statements, 61 were adopted (79%) and 16 were rejected (21%). The adoption of each statement was justified by the grade of evidence. Conclusion pCLE should be used to enhance the diagnostic arsenal in the evaluation of these indications, by providing microscopic information which improves the diagnostic performance of the physician. In order actually to implement this technology in the clinical routine, and to ensure good practice, standardised initial and continuing institutional training programmes should be established.

Fructose-asparagine is a primary nutrient during growth of Salmonella in the inflamed intestine.

Salmonella enterica serovar Typhimurium (Salmonella) is one of the most significant food-borne pathogens affecting both humans and agriculture. We have determined that Salmonella encodes an uptake and utilization pathway specific for a novel nutrient, fructose-asparagine (F-Asn), which is essential for Salmonella fitness in the inflamed intestine (modeled using germ-free, streptomycin-treated, ex-germ-free with human microbiota, and IL10−/− mice). The locus encoding F-Asn utilization, fra, provides an advantage only if Salmonella can initiate inflammation and use tetrathionate as a terminal electron acceptor for anaerobic respiration (the fra phenotype is lost in Salmonella SPI1− SPI2− or ttrA mutants, respectively). The severe fitness defect of a Salmonella fra mutant suggests that F-Asn is the primary nutrient utilized by Salmonella in the inflamed intestine and that this system provides a valuable target for novel therapies.

Substance P Mediates Proinflammatory Cytokine Release From Mesenteric Adipocytes in Inflammatory Bowel Disease Patients

Background & Aims Substance P (SP) neurokinin-1 receptors (NK-1Rs) are expressed in mesenteric preadipocytes, and SP binding activates proinflammatory signaling in these cells. We evaluated the expression levels of SP (Tac-1), NK-1R (Tacr-1), and NK-2R (Tacr-2) mRNA in preadipocytes isolated from patients with inflammatory bowel disease (IBD) and examined their responsiveness to SP compared with control human mesenteric preadipocytes. We investigated the effect of the neuropeptide SP on cytokine expression in preadipocytes of IBD versus control patients and evaluated the potential effects of these cells on IBD pathophysiology via SP-NK-R interactions. Methods Mesenteric fat was collected from control, ulcerative colitis (UC) and Crohn’s disease patients (n = 10–11 per group). Preadipocytes were isolated, expanded in culture, and exposed to substance P. Colon biopsy samples were obtained from control and IBD patients. Results Tacr-1 and -2 mRNA were increased in IBD preadipocytes compared with controls, but Tac-1 mRNA was increased only in UC preadipocytes. SP differentially regulated the expression of inflammatory mediators in IBD preadipocytes compared with controls. Disease-dependent responses to SP were also observed between Crohn’s disease and UC preadipocytes. Interleukin 17A (IL-17A) mRNA expression and release increased after SP treatment in both Crohn’s disease and UC preadipocytes; IL-17RA mRNA increased in colon biopsies samples from IBD patients. Conclusions Preadipocyte SP-NK-1R interactions during IBD may participate in IBD pathophysiology. The ability of human preadipocytes to release IL-17A in response to SP together with increased IL-17A receptors in the IBD colon suggests that a fat-colonic mucosa inflammatory loop may be active during IBD.

Molecular Signaling and Dysfunction of the Human Reactive Enteric Glial Cell Phenotype: Implications for GI Infection, IBD, POI, Neurological, Motility, and GI Disorders.

Background:Clinical observations or animal studies implicate enteric glial cells in motility disorders, irritable bowel syndrome, inflammatory bowel disease, gastrointestinal (GI) infections, postoperative ileus, and slow transit constipation. Mechanisms underlying glial responses to inflammation in human GI tract are not understood. Our goal was to identify the “reactive human enteric glial cell (rhEGC) phenotype” induced by inflammation, and probe its functional relevance. Methods:Human enteric glial cells in culture from 15 GI-surgical specimens were used to study gene expression, Ca2+, and purinergic signaling by Ca2+/fluo-4 imaging and mechanosensitivity. A nanostring panel of 107 genes was designed as a read out of inflammation, transcription, purinergic signaling, vesicular transport protein, channel, antioxidant, and other pathways. A 24-hour treatment with lipopolysaccharide (200 &mgr;g/mL) and interferon-&ggr; (10 &mgr;g/mL) was used to induce inflammation and study molecular signaling, flow-dependent Ca2+ responses from 3 mL/min to 10 mL/min, adenosine triphosphate (ATP) release, and ATP responses. Results:Treatment induced a “rhEGC phenotype” and caused up-regulation in messenger RNA transcripts of 58% of 107 genes analyzed. Regulated genes included inflammatory genes (54%/IP10; IFN-&ggr;; CxCl2; CCL3; CCL2; C3; s100B; IL-1&bgr;; IL-2R; TNF-&agr;; IL-4; IL-6; IL-8; IL-10; IL-12A; IL-17A; IL-22; and IL-33), purine-genes (52%/AdoR2A; AdoR2B; P2RY1; P2RY2; P2RY6; P2RX3; P2RX7; AMPD3; ENTPD2; ENTPD3; and NADSYN1), channels (40%/Panx1; CHRNA7; TRPV1; and TRPA1), vesicular transporters (SYT1, SYT2, SNAP25, and SYP), transcription factors (relA/relB, SOCS3, STAT3, GATA_3, and FOXP3), growth factors (IGFBP5 and GMCSF), antioxidant genes (SOD2 and HMOX1), and enzymes (NOS2; TPH2; and CASP3) (P < 0.0001). Treatment disrupted Ca2+ signaling, ATP, and mechanical/flow-dependent Ca2+ responses in human enteric glial cells. ATP release increased 5-fold and s100B decreased 33%. Conclusions:The “rhEGC phenotype” is identified by a complex cascade of pro-inflammatory pathways leading to alterations of important molecular and functional signaling pathways (Ca2+, purinergic, and mechanosensory) that could disrupt GI motility. Inflammation induced a “purinergic switch” from ATP to adenosine diphosphate/adenosine/uridine triphosphate signaling. Findings have implications for GI infection, inflammatory bowel disease, postoperative ileus, motility, and GI disorders.

Effects of obesity on severity of colitis and cytokine expression in mouse mesenteric fat. Potential role of adiponectin receptor 1

In inflammatory bowel disease (IBD), obesity is associated with worsening of the course of disease. Here, we examined the role of obesity in the development of colitis and studied mesenteric fat-epithelial cell interactions in patients with IBD. We combined the diet-induce obesity with the trinitrobenzene sulfonic acid (TNBS) colitis mouse model to create groups with obesity, colitis, and their combination. Changes in the mesenteric fat and intestine were assessed by histology, myeloperoxidase assay, and cytokine mRNA expression by real-time PCR. Medium from human mesenteric fat and cultured preadipocytes was obtained from obese patients and those with IBD. Histological analysis showed inflammatory cell infiltrate and increased histological damage in the intestine and mesenteric fat of obese mice with colitis compared with all other groups. Obesity also increased the expression of proinflammatory cytokines including IL-1β, TNF-α, monocyte chemoattractant protein 1, and keratinocyte-derived chemokine, while it decreased the TNBS-induced increases in IL-2 and IFN-γ in mesenteric adipose and intestinal tissues. Human mesenteric fat isolated from obese patients and those with and IBD demonstrated differential release of adipokines and growth factors compared with controls. Fat-conditioned media reduced adiponectin receptor 1 (AdipoR1) expression in human NCM460 colonic epithelial cells. AdipoR1 intracolonic silencing in mice exacerbated TNBS-induced colitis. In conclusion, obesity worsens the outcome of experimental colitis, and obesity- and IBD-associated changes in adipose tissue promote differential mediator release in mesenteric fat that modulates colonocyte responses and may affect the course of colitis. Our results also suggest an important role for AdipoR1 for the fat-intestinal axis in the regulation of inflammation during colitis.

Mathematical Model of the Roles of T Cells in Inflammatory Bowel Disease

Gut mucosal homeostasis depends on complex interactions among the microbiota, the intestinal epithelium, and the gut associated immune system. A breakdown in some of these interactions may precipitate inflammation. Inflammatory bowel diseases, Crohn’s disease, and ulcerative colitis are chronic inflammatory disorders of the gastrointestinal tract. The initial stages of disease are marked by an abnormally high level of pro-inflammatory helper Txa0cells, Th1. In later stages, Th2 helper cells may dominate while the Th1 response may dampen. The interaction among the Txa0cells includes the regulatory Txa0cells (Treg). The present paper develops a mathematical model by a system of differential equations with terms nonlocal in the space spanned by the concentrations of cytokines that represents the interaction among Txa0cells through a cytokine signaling network. The model demonstrates how the abnormal levels of Txa0cells observed in inflammatory bowel diseases can arise from abnormal regulation of Th1 and Th2 cells by Treg cells.

Correlation of Biomarker Expression in Colonic Mucosa with Disease Phenotype in Crohn's Disease and Ulcerative Colitis.

AbstractBackgroundnInflammatory bowel diseases (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), are characterized by chronic intestinal inflammation due to immunological, microbial, and environmental factors in genetically predisposed individuals. Advances in the diagnosis, prognosis, and treatment of IBD require the identification of robust biomarkers that can be used for molecular classification of diverse disease presentations. We previously identified five genes, RELA, TNFAIP3 (A20), PIGR, TNF, and IL8, whose mRNA levels in colonic mucosal biopsies could be used in a multivariate analysis to classify patients with CD based on disease behavior and responses to therapy.AimWe compared expression of these five biomarkers in IBD patients classified as having CD or UC, and in healthy controls.ResultsPatients with CD were characterized as having decreased median expression of TNFAIP3, PIGR, and TNF in non-inflamed colonic mucosa as compared to healthy controls. By contrast, UC patients exhibited decreased expression of PIGR and elevated expression of IL8 in colonic mucosa compared to healthy controls. A multivariate analysis combining mRNA levels for all five genes resulted in segregation of individuals based on disease presentation (CD vs. UC) as well as severity, i.e., patients in remission versus those with acute colitis at the time of biopsy.ConclusionWe propose that this approach could be used as a model for molecular classification of IBD patients, which could further be enhanced by the inclusion of additional genes that are identified by functional studies, global gene expression analyses, and genome-wide association studies.

Cytomegalovirus-Related Hospitalization Is Associated With Adverse Outcomes and Increased Health-Care Resource Utilization in Inflammatory Bowel Disease

Objectives:Impact of cytomegalovirus (CMV)-related hospitalization in inflammatory bowel disease (IBD) patients is unknown. The aim of this study was to determine hospital outcomes of CMV-related hospitalization in IBD patients in a large national in-patient administrative data set.Methods:This was a cross-sectional study using data from the Nationwide In-patient Sample database. IBD- and CMV-related hospitalizations between 2003 and 2011 were identified using appropriate ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) codes. Impact of CMV-related hospitalization on in-hospital mortality, length of stay (LOS), and hospital charges were quantified.Results:CMV-related hospitalization was associated with higher in-hospital mortality (odds ratio (OR) 7.09, 95% confidence interval (CI) 3.38–14.85), prolonged LOS (7.77 days, P<0.0001), and more hospital charge (US