Use of blood based biomarkers in the evaluation of Crohn’s disease and ulcerative colitis

Evolving Experimental Platforms to Evaluate Ulcerative Colitis

Ulcerative colitis (UC) is a multifactorial disease defined by chronic intestinal inflammation with idiopathic origins. It has a predilection to affect the mucosal lining of the large intestines and rectum. Management of UC depends upon numerous factors that include disease pathogenesis and severity that are maintained via medical or surgical means. Chronic inflammation that is left untreated or managed poorly from a clinical stance can result in intestinal ulceration accompanied by resulting physiological dysfunction. End-stage UC is mediated by surgical intervention with the resection of diseased tissue. This can lead to numerous health-related quality of life issues but is considered a curative approach. Regimens to treat UC are ever evolving and find their basis within various platforms to evaluate and treat UC. Numerous modeling systems have been examined to delineate potential mechanisms of action. However, UC is a heterogenous disease spanning unknown genetic origins coupled with environmental factors that can influence disease outcomes and related treatment procedures. Unfortunately, there is no one-size-fits-all model to fully assess all facets of UC. Within the context of this review article, the utility of various approaches that have been employed to gain insight into different aspects of UC will be investigated.

Common functional alterations identified in blood transcriptome of autoimmune cholestatic liver and inflammatory bowel diseases

Primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and inflammatory bowel diseases (IBDs), including Crohn’s disease (CD) and ulcerative colitis (UC), are heterogeneous chronic autoimmune diseases that may share underlying pathogenic mechanisms. Herein, we compared simultaneously analyzed blood transcriptomes from patients with PBC, PSC, and IBD. Microarray-based measurements were conducted using RNA isolated from whole blood samples from 90, 45, 95 and 93 patients with PBC, PSC, CD, and UC, respectively, and 47 healthy controls. Expression levels of selected transcripts were analyzed by quantitative reverse-transcribed PCR using an independent cohort of 292, 71 and 727 patients with PBC, PSC, and IBD, respectively. Of 4026, 2650 and 4967 probe sets differentially expressed (adjusted p-value < 0.05) in samples from patients with PBC, PSC, and IBD, respectively, compared with healthy controls, 1946 were common to all three comparisons. Functional analyses indicated that most terms enriched for genes differentially expressed in PBC, PSC, and IBD patients compared with healthy controls were related to mitochondrial function, the vesicle endomembrane system, and GTPase-mediated processes. This study indicates that microarray-based profiling of blood gene expression supports research into the molecular mechanisms underlying disease, rather than being useful for selection of diagnostic biomarkers for use in clinical practice.

Redefining the Practical Utility of Blood Transcriptome Biomarkers in Inflammatory Bowel Diseases

BACKGROUND AND AIMS

The study investigates the practical utility of whole-blood gene expression profiling to diagnose inflammatory bowel diseases [IBDs].

METHODS

The discovery cohorts included 102 and 51 paediatric IBD patients and controls, and 95 and 46 adult IBD patients and controls, respectively. The replication cohorts included 447 and 76 paediatric IBD patients and controls, and 271 and 108 adult IBD patients and controls, respectively. In the discovery phase, RNA samples extracted from whole peripheral blood were analysed using RNA-Seq, and the predictive values of selected biomarkers were validated using quantitative polymerase chain reaction [qPCR].

RESULTS

In all, 15 differentially expressed transcripts [adjusted p ≤0.05] were selected from the discovery sequencing datasets. The receiver operating characteristic curves and area under the curve [ROC-AUC] in replication analyses showed high discriminative power [AUC range, 0.91-0.98] for 11 mRNAs in paediatric patients with active IBD. By contrast, the AUC-ROC values ranged from 0.63 to 0.75 in comparison among inactive paediatric IBDs and active/inactive adult IBDs, indicating a lack of discriminative power. The best multi-mRNA diagnostic classifier showed moderate discriminative power [AUC = 0.81] for paediatric inactive IBD, but was not able to discriminate active or inactive adult IBD patients from controls. The AUC-ROC values did not confirm an ability of the mRNAs abundances to discriminate between active ulcerative colitis and active Crohn's disease in paediatric or adult populations.

CONCLUSIONS

This study identifies and validates blood transcriptional biomarkers that could be used in clinical settings as diagnostic predictors of IBD clinical activity in paediatric, but not adult, IBD patients.

High-dimensional immune phenotyping and transcriptional analyses reveal robust recovery of viable human immune and epithelial cells from frozen gastrointestinal tissue

Simultaneous analyses of peripheral and mucosal immune compartments can yield insight into the pathogenesis of mucosal-associated diseases. Although methods to preserve peripheral immune cells are well established, studies involving mucosal immune cells have been hampered by lack of simple storage techniques. We provide a cryopreservation protocol allowing for storage of gastrointestinal (GI) tissue with preservation of viability and functionality of both immune and epithelial cells. These methods will facilitate translational studies allowing for batch analysis of mucosal tissue to investigate disease pathogenesis, biomarker discovery and treatment responsiveness.

New Biomarkers for Diagnosing Inflammatory Bowel Disease and Assessing Treatment Outcomes

Despite advances in our understanding of the pathophysiology underlying inflammatory bowel disease, there remains a significant need for biomarkers that can differentiate between Crohn's disease and ulcerative colitis with high sensitivity and specificity, in a cost-efficient manner. As the focus on personalized approaches to the delivery of medical treatment increases, new biomarkers are being developed to predict an individual's response to therapy and their overall disease course. In this review, we will outline many of the existing and recently developed biomarkers, detailing their role in the assessment of patients with inflammatory bowel disease. We will identify opportunities for improvement in our biomarkers, including better differentiation between the subtypes of inflammatory bowel disease. We will also discuss new targets and strategies in biomarker development, including combining modalities to create biomarker signatures to improve the ability to predict disease courses and response to therapy among individual patients.

Gene expression profiles of putative biomarker candidates in Mycobacterium avium subsp. paratuberculosis-infected cattle

This study was conducted to analyze the gene expression of prognostic potential biomarker candidates using the whole blood of cattle naturally infected with ITALIC! Mycobacterium aviumsubsp. ITALIC! paratuberculosis(MAP). We conducted real-time PCR to evaluate 23 potential biomarker candidates. Experimental animals were divided into four groups based on fecal MAP PCR and serum ELISA. Seven ( ITALIC! KLRB1, ITALIC! HGF, ITALIC! MPO, ITALIC! LTF, ITALIC! SERPINE1, ITALIC! S100A8and ITALIC! S100A9) genes were up-regulated in fecal MAP-positive cattle and three ( ITALIC! KLRB1, ITALIC! MPOand ITALIC! S100A9) were up-regulated in MAP-seropositive cattle relative to uninfected cattle. In subclinically infected animals, 17 genes ( ITALIC! TFRC, ITALIC! S100A8, ITALIC! S100A9, ITALIC! MPO, ITALIC! GBP6, ITALIC! LTF, ITALIC! KLRB1, ITALIC! SERPINE1, ITALIC! PIGR, ITALIC! IL-10, ITALIC! CXCR3, ITALIC! CD14, ITALIC! MMP9, ITALIC! ELANE, ITALIC! CHI3L1, ITALIC! HPand ITALIC! HGF) were up-regulated compared with the control group. Moreover, six genes ( ITALIC! CXCR3, ITALIC! HP, ITALIC! HGF, ITALIC! LTF, ITALIC! TFRCand ITALIC! GBP6) showed significant differences between experimental groups. Taken together, our data suggest that six genes ( ITALIC! LTF, ITALIC! HGF, ITALIC! HP, ITALIC! CXCR3, ITALIC! GBP6and ITALIC! TFRC) played essential roles in the immune response to MAP during the subclinical stage and therefore might be useful as prognostic biomarkers.