Fecal excretion of deoxyribonucleic acid in long-term follow-up of patients with inactive ulcerative colitis

Circulating Free DNA and Its Emerging Role in Autoimmune Diseases

Liquid biopsies can be used to analyse tissue-derived information, including cell-free DNA (cfDNA), circulating rare cells, and circulating extracellular vesicles in the blood or other bodily fluids, representing a new way to guide therapeutic decisions in cancer. Among the new challenges of liquid biopsy, we found clinical application in nontumour pathologies, including autoimmune diseases. Since the discovery of the presence of high levels of cfDNA in patients with systemic lupus erythaematosus (SLE) in the 1960s, cfDNA research in autoimmune diseases has mainly focused on the overall quantification of cfDNA and its association with disease activity. However, with technological advancements and the increasing understanding of the role of DNA sensing receptors in inflammation and autoimmunity, interest in cfDNA and autoimmune diseases has not expanded until recently. In this review, we provide an overview of the basic biology of cfDNA in the context of autoimmune diseases as a biomarker of disease activity, progression, and prediction of the treatment response. We discuss and integrate available information about these important aspects.

Cell-Free Nucleic Acids and their Emerging Role in the Pathogenesis and Clinical Management of Inflammatory Bowel Disease

Cell-free nucleic acids (cfNAs) are defined as any nucleic acids that are present outside the cell. They represent valuable biomarkers in various diagnostic protocols such as prenatal diagnostics, the detection of cancer, and cardiovascular or autoimmune diseases. However, in the current literature, little is known about their implication in inflammatory bowel disease (IBD). IBD is a group of multifactorial, autoimmune, and debilitating diseases with increasing incidence worldwide. Despite extensive research, their etiology and exact pathogenesis is still unclear. Since cfNAs were observed in other autoimmune diseases and appear to be relevant in inflammatory processes, their role in the pathogenesis of IBD has also been suggested. This review provides a summary of knowledge from the available literature about cfDNA and cfRNA and the structures involving them such as exosomes and neutrophil extracellular traps and their association with IBD. Current studies showed the promise of cfNAs in the management of IBD not only as biomarkers distinguishing patients from healthy people and differentiating active from inactive disease state, but also as a potential therapeutic target. However, the detailed biological characteristics of cfNAs need to be fully elucidated in future experimental and clinical studies.

Novel Biomarkers and the Future Potential of Biomarkers in Inflammatory Bowel Disease

There is increasing importance placed upon noninvasive assessment of gut inflammation. These tools are likely to be the key in differentiating intestinal inflammatory disease from functional disorders and in monitoring the response to intervention in individuals with known inflammatory conditions. Although various noninvasive markers are currently available, they have limitations and do not provide ideal utility. This review focuses on emerging markers of gut inflammation, highlighting the potential of specific markers.

Utility of surrogate markers for the prediction of relapses in inflammatory bowel diseases

Patients with diagnosed inflammatory bowel disease (IBD) will commonly experience a clinical relapse in spite of a prolonged therapy-induced period of clinical remission. The current methods of assessing subclinical levels of low-grade inflammation which predispose patients to relapse are not optimal when considering both cost and patient comfort. Over the past few decades, much investigation has discovered that proteins such as calprotectin that are released from inflammatory cells are capable of indicating disease activity. Along with C-reactive protein and erythrocyte sedimentation rate, calprotectin has now become part of the current methodology for assessing IBD activity. More recently, research has identified that other fecal and serum biomarkers such as lactoferrin, S100A12, GM-CSF autoantibodies, α1-antitrypsin, eosinophil-derived proteins, and cytokine concentrations have variable degrees of utility in monitoring gastrointestinal tract inflammation. In order to provide direction toward novel methods of predicting relapse in IBD, we provide an up-to-date review of these biomarkers and their potential utility in the prediction of clinical relapse, given their observed activities during various stages of clinical remission.

Faecal calprotectin: Management in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic and relapsing disorder which leads to an inflammation of the gastrointestinal tract. A tailored therapy to achieve mucosal healing with the less adverse events has become a key issue in the management of IBD. In the past, the clinical remission was the most important factor to consider for adapting diagnostic procedures and therapeutic strategies. However, there is no a good correlation between symptoms and intestinal lesions, so currently the goals of treatment are to achieve not only the control of symptoms, but deep remission, which is related with a favourable prognosis. Thus, the determination of biological markers or biomarkers of intestinal inflammation play a crucial role. Many biomarkers have been extensively evaluated in IBD showing significant correlation with endoscopic lesions, risk of recurrence and response to treatment. One of the most important markers is faecal calprotectin (FC). Despite calprotectin limitations, this biomarker represents a reliable and noninvasive alternative to reduce the need for endoscopic procedures. FC has demonstrated its performance for regular monitoring of IBD patients, not only to the diagnosis for discriminating IBD from non-IBD diagnosis, but for assessing disease activity, relapse prediction and response to therapy. Although, FC provides better results than other biomarkers such as C-reactive protein and erythrocyte sedimentation rate, these surrogate markers of intestinal inflammation should not be used isolation but in combination with other clinical, endoscopic, radiological or/and histological parameters enabling a comprehensive assessment of IBD patients.

Excretion of Host DNA in Feces Is Associated with Risk of Clostridium difficile Infection

Clostridium difficile infection (CDI) is intricately linked to the health of the gastrointestinal tract and its indigenous microbiota. In this study, we assessed whether fecal excretion of host DNA is associated with CDI development. Assuming that shedding of epithelial cell increases in the inflamed intestine, we used human DNA excretion as a marker of intestinal insult. Whole-genome shotgun sequencing was employed to quantify host DNA excretion and evaluate bacterial content in fecal samples collected from patients with incipient CDI, hospitalized controls, and healthy subjects. Human DNA excretion was significantly increased in patients admitted to the hospital for a gastrointestinal ailment, as well as prior to an episode of CDI. In multivariable analyses, human read abundance was independently associated with CDI development. Host DNA proportions were negatively correlated with intestinal microbiota diversity. Enterococcus and Escherichia were enriched in patients excreting high quantities of human DNA, while Ruminococcus and Odoribacter were depleted. These findings suggest that intestinal inflammation can occur prior to CDI development and may influence patient susceptibility to CDI. The quantification of human DNA in feces could serve as a simple and noninvasive approach to assess bowel inflammation and identify patients at risk of CDI.

The role and utility of faecal markers in inflammatory bowel disease

Crohn's disease and ulcerative colitis are characterized by periods of symptomatic relapse and remission. Diagnosis and assessment of inflammatory bowel disease has so far been based on clinical evaluation, serum parameters, radiology and endoscopy. Faecal markers such as calprotectin or lactoferrin have emerged as new diagnostic tools to detect and monitor intestinal inflammation. This review focuses on their potential clinical applications and limitations in the management of inflammatory bowel disease.

Faecal calprotectin in HIV-infected, HAART-naïve Ugandan children

OBJECTIVES

Calprotectin is a calcium- and zinc-binding protein and a marker in faeces of gastrointestinal inflammation. Reference values have been established in children older than 4 years. The aim of the present study was to determine the concentration of faecal calprotectin (FC) in human immunodeficiency virus (HIV)-infected, highly active antiretroviral therapy-naïve Ugandan children and compare it with the reference value.

METHODS

We tested 193 HIV-infected children ages 0 to 12 years in a hospital-based survey for FC. A standardised interview with sociodemographic information and medical history was used to assess risk factors. A cluster of differentiation 4 (CD4) cell percentage was prevalent in all of the children.

RESULTS

The median FC concentrations decreased with increasing age, as in healthy children. The median concentration was 208 mg/kg in infants 0 to 1 year, 171 mg/kg among toddlers 1 to 4 years, and 62 mg/kg for children 4 to 12 years. Children with advanced disease and a low CD4 cell percentage had significantly higher FC concentrations than those with a high CD4 cell percentage. Children older than 4 years with diarrhoea had significantly higher FC concentrations compared with those without diarrhoea.

CONCLUSIONS

HIV-infected children older than 4 years had a median FC concentration above the reference value, and gut inflammation in the children with elevated values is likely. Children with more advanced disease had increased FC concentrations regardless of age.

Citrulline as a marker for chemotherapy induced mucosal barrier injury in pediatric patients

BACKGROUND

The currently used National Cancer Institute (NCI) adverse events criteria for mucosal barrier injury (MBI) are insufficient for use in children. We searched for objective, easily measurable indicators for MBI in children with cancer.

PURPOSE

In children with acute myeloid leukemia, various MBI-related clinical and laboratory tests were investigated, reflecting clinical severity (NCI symptomatic adverse events criteria (gold standard), daily gut score (DGS)), inflammation (plasma and fecal interleukin-8 (IL-8), fecal calprotectin), enterocytic loss (plasma citrulline, ratio fecal human DNA/total DNA) and intestinal permeability (sugar absorption tests).

RESULTS

Intestinal MBI as detected by the NCI adverse events criteria was found in 55% of chemotherapy cycles, correlating well with the continuous DGS (n = 55, rho = 0.581; P < 0.001). Intestinal cell loss as measured by the ratio fecal human DNA/total DNA and plasma citrulline correlated well with both NCI criteria (n = 61, rho = 0.357, P = 0.005 resp. n = 58, rho = -0.482; P < 0.001) and DGS (n = 54, rho = 0.352, P = 0.009 resp. n = 55, rho = -0.625; P < 0.001). Plasma IL-8 correlated strongly to plasma citrulline (n = 46, rho = -0.627; P < 0.001).

CONCLUSIONS

MBI was reflected by parameters indicating inflammation (IL-8) and cell loss (plasma citrulline, ratio fecal human DNA/total DNA). We conclude that plasma citrulline might be a good parameter for MBI. Further studies are needed to show whether plasma citrulline can be used as a marker for MBI in future research.

Questions and answers on the role of faecal calprotectin as a biological marker in inflammatory bowel disease

Faecal calprotectin has been proposed as a non-invasive surrogate marker of intestinal inflammation in inflammatory bowel disease. Close correlation between faecal calprotectin concentration and faecal leukocyte excretion quantified with (111)indium has been described. This faecal marker can be detected using simple and cheap techniques. Faecal calprotectin has a good diagnostic precision for separating organic and functional intestinal diseases. However, the specificity for the diagnosis of inflammatory bowel disease is lower than desirable, as several diseases other than inflammatory bowel disease -- specially colorectal neoplasia and gastrointestinal infection -- can also increase faecal calprotectin. High concentration of calprotectin in faeces is a strong argument to carry out a colonoscopy in order to rule out the presence of inflammatory bowel disease or other organic pathologies. Parallelism between faecal calprotectin levels and inflammatory bowel disease activity has been confirmed, although this faecal marker appears to better reflect the disease activity in ulcerative colitis than in Crohn's disease. Faecal calprotectin's capacity to predict inflammatory bowel diseases relapse is promising. It has been suggested that, in inflammatory bowel disease patients receiving treatment, a normalization or decrease in faecal calprotectin concentrations is an accurate indicator of endoscopic healing. Greater faecal calprotectin concentration has been shown in asymptomatic first-degree relatives of patients with inflammatory bowel disease, suggesting that there is a high prevalence of subclinical intestinal inflammation in them.