Current and future role of biomarkers in Crohn's disease risk assessment and treatment

Serological markers facilitate the diagnosis of Crohn's disease

Background and aim: The diagnosis of Crohn's disease (CD) is challenging. Ongoing search for biomarkers to facilitate the diagnosis is a worthwhile endeavor. The aim of this study was to explore the role of serological markers in the diagnosis of CD at an inflammatory bowel disease (IBD) referral center.Methods: This was a retrospective study including 196 suspected CD patients. The expression of ASCA-IgG, ASCA-IgA, AYMA-IgG, AYCA-IgA, FI2Y-IgG, and pANCA in the patient's serum was determined by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IF).Results: ASCA was a relatively specific marker for CD (p = 0.0005), but not AYMA-IgG, AYCA-IgA, F12Y-IgG (p = 0.5936, 0.7974, 0.1085, respectively). However, a high sensitivity of 96.77% (95% CI 90.19%-99.83%) was noted for ASCA+/FI2Y+ to identify CD patients among the suspected cases, albeit with low PPV. The more combinations of serological markers, the higher sensitivity, and NPV. No correlation was found between the age of onset or disease location and the expression of ASCA, AYMA, AYCA, FI2Y, or pANCA. There was no significant difference between the expression of ASCA and the disease behavior at diagnosis (p = 0.3307). However, a decreased proportion of AYMA+ CD patients was found in those who received surgery compared with their non-surgical counterparts (p = 0.0488).Conclusions: ASCA was found to be the most accurate serological marker for the differential diagnosis of CD. Combinations of ASCA, AYMA, AYCA, and FI2Y improved diagnostic accuracy of CD.

Biomarkers: Delivering on the expectation of molecularly driven, quantitative health

Biomarkers are the pillars of precision medicine and are delivering on expectations of molecular, quantitative health. These features have made clinical decisions more precise and personalized, but require a high bar for validation. Biomarkers have improved health outcomes in a few areas such as cancer, pharmacogenetics, and safety. Burgeoning big data research infrastructure, the internet of things, and increased patient participation will accelerate discovery in the many areas that have not yet realized the full potential of biomarkers for precision health. Here we review themes of biomarker discovery, current implementations of biomarkers for precision health, and future opportunities and challenges for biomarker discovery. Impact statement Precision medicine evolved because of the understanding that human disease is molecularly driven and is highly variable across patients. This understanding has made biomarkers, a diverse class of biological measurements, more relevant for disease diagnosis, monitoring, and selection of treatment strategy. Biomarkers' impact on precision medicine can be seen in cancer, pharmacogenomics, and safety. The successes in these cases suggest many more applications for biomarkers and a greater impact for precision medicine across the spectrum of human disease. The authors assess the status of biomarker-guided medical practice by analyzing themes for biomarker discovery, reviewing the impact of these markers in the clinic, and highlight future and ongoing challenges for biomarker discovery. This work is timely and relevant, as the molecular, quantitative approach of precision medicine is spreading to many disease indications.

CD69 is the crucial regulator of intestinal inflammation: a new target molecule for IBD treatment?

CD69 has been identified as an early activation marker of lymphocytes. However, recent work has indicated that CD69 plays an essential role for the regulation of inflammatory processes. Particularly, CD69 is highly expressed by lymphocytes at mucosal sites being constantly exposed to the intestinal microflora (one of the nature's most complex and most densely populated microbial habitats) and food antigens, while only a small number of circulating leukocytes express this molecule. In this review we will discuss the role of CD69 in mucosal tissue and consider CD69 as a potential target for the development of novel treatments of intestinal inflammation.

Serum antibodies to microbial antigens for Crohn's disease progression: a meta-analysis

OBJECTIVES

This meta-analysis evaluated the stratification powers of four well-studied serum antibodies to microbial antigens [ASCA (anti-Saccharomyces cerevisiae), anti-OmpC (anti-outer-membrane protein C), anti-I2 (anti-Pseudomonas fluorescens-associated sequence I2), and anti-CBir1 (anti-bacterial flagellin)] in characterizing progression of Crohn's disease (CD).

METHODS

Pooled sensitivity, specificity, and diagnostic odds ratio (DOR) with 95% confidence intervals (CI) for individual antibodies and antibody combination were used to evaluate and compare their stratification powers for CD-related complications and the need for surgery.

RESULTS

Eleven studies were included in this meta-analysis. In terms of the outcomes for CD complication and surgery, ASCA had the highest sensitivities at 0.66 (CI 0.63-0.69) for complications and 0.66 (CI 0.63-0.68) for surgery, whereas anti-OmpC had the highest specificities at 0.83 (CI 0.80-0.85) for complications and 0.81 (CI 0.79-0.83) for surgery. Anti-OmpC had the highest DORs at 2.61 (CI 2.16-3.15) for complications and 2.93 (CI 2.48-3.47) for surgery, and a combination of at least two antibodies presented pooled DORs at 2.93 (CI 2.42-3.56) for complications and 3.39 (CI 2.73-4.20) for surgery, superior to any single antibody.

CONCLUSION

Anti-OmpC had the highest stratification power among the four antibodies screened for the risk of both complications and surgery in CD patients, and the power became stronger when antibodies were assessed in combination.

Biomarkers in inflammatory bowel diseases: Current status and proteomics identification strategies

Unambiguous diagnosis of the two main forms of inflammatory bowel diseases (IBD): Ulcerative colitis (UC) and Crohn’s disease (CD), represents a challenge in the early stages of the diseases. The diagnosis may be established several years after the debut of symptoms. Hence, protein biomarkers for early and accurate diagnostic could help clinicians improve treatment of the individual patients. Moreover, the biomarkers could aid physicians to predict disease courses and in this way, identify patients in need of intensive treatment. Patients with low risk of disease flares may avoid treatment with medications with the concomitant risk of adverse events. In addition, identification of disease and course specific biomarker profiles can be used to identify biological pathways involved in the disease development and treatment. Knowledge of disease mechanisms in general can lead to improved future development of preventive and treatment strategies. Thus, the clinical use of a panel of biomarkers represents a diagnostic and prognostic tool of potentially great value. The technological development in recent years within proteomic research (determination and quantification of the complete protein content) has made the discovery of novel biomarkers feasible. Several IBD-associated protein biomarkers are known, but none have been successfully implemented in daily use to distinguish CD and UC patients. The intestinal tissue remains an obvious place to search for novel biomarkers, which blood, urine or stool later can be screened for. When considering the protein complexity encountered in intestinal biopsy-samples and the recent development within the field of mass spectrometry driven quantitative proteomics, a more thorough and accurate biomarker discovery endeavor could today be performed than ever before. In this review, we report the current status of the proteomics IBD biomarkers and discuss various emerging proteomic strategies for identifying and characterizing novel biomarkers, as well as suggesting future targets for analysis.

Select a suitable treatment strategy for Crohn's disease: step-up or top-down

Crohn's Disease (CD) is a chronic immune-mediated disorder with progressive and destructive course. Current guidelines on the treatment strategy still recommend a step-up approach with sequential prescription of corticosteroids and immunosuppressives. However, mounting evidences manifested that top-down therapy with early administration of anti-TNF or combination of immunosuppressives can achieve more rapid and higher rate of mucosal healing and has the potential of modifying the natural course of disease. Therefore, who is suitable to accept and when to start anti-TNF therapy have attracted the attention of gastroenterologists. And what benefit/risk can be expected from the two strategies should be carefully taken into account by clinicians. Age stratification, special patients, disease location and extension, genetic and serologic testing are predictors of disease progression and complication and thus guide a personalized treatment approach in CD. A definition of early CD has been proposed to select an algorithm for treatment of moderate-to-severe CD with a suitable strategy. To date mucosal healing has been widely used, the Lémann score, which assesses the extent and severity of bowel damage at a specific time-point and over time, and is a new disability index for patients with CD, will be considered as a new endpoint for future studies of treatment strategies. Besides medicines of the two strategies, surgery, vaccine, Leukocytapheresis and stem cell therapy are all effective therapeutic approaches which lead to another thinking about what should they be putted in the conditional pyramid. However, we are trying to answer these questions.

P4 medicine: how systems medicine will transform the healthcare sector and society

Ten years ago, the proposition that healthcare is evolving from reactive disease care to care that is predictive, preventive, personalized and participatory was regarded as highly speculative. Today, the core elements of that vision are widely accepted and have been articulated in a series of recent reports by the US Institute of Medicine. Systems approaches to biology and medicine are now beginning to provide patients, consumers and physicians with personalized information about each individual's unique health experience of both health and disease at the molecular, cellular and organ levels. This information will make disease care radically more cost effective by personalizing care to each person's unique biology and by treating the causes rather than the symptoms of disease. It will also provide the basis for concrete action by consumers to improve their health as they observe the impact of lifestyle decisions. Working together in digitally powered familial and affinity networks, consumers will be able to reduce the incidence of the complex chronic diseases that currently account for 75% of disease-care costs in the USA.

Anti-Saccharomyces cerevisiae antibodies are elevated in Graves' disease but not in Hashimoto's thyroiditis

BACKGROUND

Anti-Saccharomyces cerevisiae antibodies (ASCA) had been known to be specific for Crohn's disease, but they had also been found in many other autoimmune diseases.

AIM

The aim of this study was to evaluate the prevalence of ASCA in patients with autoimmune thyroid disease (AITD).

PATIENTS AND METHODS

One hundred and ninety-seven patients with AITD and 160 healthy controls were included in the study. One hundred and nineteen patients had Graves' disease (GD) and 78 patients had Hashimoto's thyroiditis (HT). ASCA IgG and IgA were determined by ELISA.

RESULTS

ASCA IgG were significantly more frequent in patients with GD than in control group (11.8% vs. 3.1%, p = 0.002). In HT, the frequency of ASCA IgG was similar to that of the control group (3.8% and 3.1% respectively). The frequency of ASCA IgA was similar in GD (0.8%), HT (2.6%), and the control group (3.1%). In all GD patients, the frequency of ASCA IgG was significantly higher than that of ASCA IgA (11.8% vs. 0.8%, p = 0.001). These results were also true even in male and female groups (10.4% vs. 1.3%, p = 0.01 and 14.3% vs. 0%, p = 0.01, respectively). ASCA IgG levels were significantly higher in GD patients (6.7 ± 11.1 vs. 2.2 ± 2.8, p = 3 × 10(-6)) and in HT patients (4.2 ± 4.7 vs. 2.2 ± 2.8, p = 0.0002) than those in the control group. ASCA IgA levels were comparable among patients with GD, HT, and the control group. In GD patients, the mean titer of ASCA IgG was significantly higher than that of ASCA IgA (6.7 ± 11.1 vs. 3.6 ± 4.2, p = 0.005).

CONCLUSION

Patients with GD had a higher frequency of ASCA IgG than controls.

Using gene expression data to identify certain gastro-intestinal diseases

Background

Inflammatory bowel diseases, ulcerative colitis and Crohn’s disease are considered to be of autoimmune origin, but the etiology of irritable bowel syndrome remains elusive. Furthermore, classifying patients into irritable bowel syndrome and inflammatory bowel diseases can be difficult without invasive testing and holds important treatment implications. Our aim was to assess the ability of gene expression profiling in blood to differentiate among these subject groups.

Methods

Transcript levels of a total of 45 genes in blood were determined by quantitative real-time polymerase chain reaction (RT-PCR). We applied three separate analytic approaches; one utilized a scoring system derived from combinations of ratios of expression levels of two genes and two different support vector machines.

Results

All methods discriminated different subject cohorts, irritable bowel syndrome from control, inflammatory bowel disease from control, irritable bowel syndrome from inflammatory bowel disease, and ulcerative colitis from Crohn’s disease, with high degrees of sensitivity and specificity.

Conclusions

These results suggest these approaches may provide clinically useful prediction of the presence of these gastro-intestinal diseases and syndromes.

Genetics in diagnosing and managing inflammatory bowel disease

We believe the future clinical application of genomic information in IBD will lie in the use of a combination of “gene-chips” designed specifically for variation relevant to IBD and ultimately in the cataloging of an individual’s entire collection of genomic variation through whole-genome sequencing. In the short term, the expansion of pharmacogenomic tests and biomarker assessments are likely to have the most significant influence on prescribed IBD treatment therapies and disease management. Moreover, these pharmacogenomic and biomarker data are likely to benefit greatly from the ongoing genomic analyses, as they can begin to put these data in the proper genetic context as they relate to monitoring and assessing these effects across different ethnic and racial populations. Although mentioned only briefly in this review, a clearer understanding of environmental triggers of IBD will be of utmost importance to furthering our understanding of the genetic factors and the complex interactions that are likely to exist between genes and environment. The successful identification of genetic factors influencing IBD risk has been accelerating over the last few years and is likely to continue. Currently, these genetic factors provide no direct bearing on clinical treatments or therapies. Instead, these findings aid in our understanding of disease pathogenesis and indirectly to potential for development of novel therapeutics. In the near term, they may be able to provide some additional utility in distinguishing CD cases from UC cases. Future use of genomic information and its role in diagnosing and managing IBD patients is promising but not yet mature. The search for the so-called missing heritability in IBD will undoubtedly continue to uncover novel genes, biological pathways, and the likely interplay between genetic variation and environmental factors. The creation of a customized gene-chip (allowing for the creation of a patient-specific cataloging of IBD relevant genetic information), for use in clinical practice, is an almost certainty. Although this information will likely provide significant aid to diagnostics and treatment, it is doubtful that it could ever fully stand alone. It must be accompanied by thorough clinical evaluation and data, a more complete characterization of a patient’s potential environmental triggers, and integration with other known pharmacogenomic and molecular biomarker information.

Implementing changes in clinical practice to improve the management of Crohn's disease

The introduction of anti-tumour necrosis factor therapies has provided highly effective treatments for Crohn's disease, making it possible to significantly improve the prognosis of patients. However, neither conventional non-biological therapies nor anti-tumour necrosis factor therapies are routinely used to optimum effect. There are several reasons for this, including a lack of specific evidence to guide common clinical questions and a lack of clearly defined treatment targets. This paper suggests some simple changes to the management of Crohn's disease that have the potential to significantly improve patient outcomes. A new treatment target, 'deep remission', which includes mucosal healing as well as clinical remission, may be the first step in defining the successful treatment of Crohn's disease; early clinical studies have demonstrated that this is a readily achievable target. Initiating appropriate treatment early can increase clinical remission rates, improve steroid sparing, induce mucosal healing and prevent structural bowel damage, whereby reducing the need for hospitalization and surgery. There are also clear indications that modifying treatment based on regular objective assessments of disease activity to provide tight disease control can improve patient outcomes in a similar way to that observed in rheumatoid arthritis. These simple changes to management strategy appear to allow the full potential of available treatments to be realized. Clinical studies to further define optimized treatment strategies for Crohn's disease are underway and will provide future direction.

Progress in research of biological activity markers for inflammatory bowel disease

The incidence of inflammatory bowel disease (IBD) has been increasing in recent years. The clinical manifestations of IBD are complicated, and both intestinal and extraintestinal symptoms may develop. Due to the lack of specific index, IBD is easy to be misdiagnosed, and evaluating disease activity is more difficult. Radiology, endoscopic and histological biopsy for diagnosis are expensive. Currently, there is an urgent need of a simple, noninvasive, sensitive, economic, and highly specific method for diagnosis of IBD. Biological activity markers may meet this demand. In this paper, the clinical applicability of biological activity markers, which come from both ulcerative colitis (UC) and Crohn's disease (CD), in identifying the presence or extent of inflammatory response, is reviewed.

Current and future role of serogenomics in ulcerative colitis

Ulcerative colitis (UC), a chronic inflammatory bowel disease, occurs in genetically susceptible individuals who mount inappropriate immune responses to endoluminal antigens. Serologic and genetic markers have shown great potential for clinical application in Crohn's disease (CD), particularly for prognostication. However, their use is not as well established in UC. The aim of this paper is to highlight the clinical relevance of these markers for diagnostics and prognostication in UC. This review identified studies that cited the use of serum and genetic biomarkers in UC when these biomarkers were used in diagnostic, prognostic, and therapeutic response prediction applications. Several serologic and genetic markers associated with UC were identified, and this review presents and summarizes these data, focusing on the biomarkers' established and emerging diagnostic and prognostic utility. Although more established in CD, the data provided by serologic and genetic testing in UC has the potential to enhance clinical decision making.

Ruling out IBD: estimation of the possible economic effects of pre-endoscopic screening with F-calprotectin

OBJECTIVES

To estimate the possible economic effects of a sequential testing strategy with F-calprotectin to minimize colonoscopies.

DESIGN AND METHODS

Retrospective study in a third party payer perspective. The costs were calculated from initial F-calprotectin test results of 3639 patients. Two cut-off levels were used: 50 μg/g feces and 100 μg/g feces, respectively. The cost-effectiveness of the testing strategy was estimated through the short-term cost avoidance and reduction in demand for colonoscopies.

RESULTS

The estimated demand for colonoscopies was reduced by 50% with the 50 μg/g cut-off and 67% with the 100 μg/g cut-off. This corresponded to a cost avoidance of approximately €1.57 million and €2.13 million, respectively.

CONCLUSIONS

The use of F-calprotectin as a screening test substantially could reduce the number of invasive measurements necessary in the diagnostic work-up of patients with suspected IBD, as well as the associated costs.