Functional and clinical aspects of the myelomonocyte protein calprotectin

High level of fecal calprotectin at age 2 months as a marker of intestinal inflammation predicts atopic dermatitis and asthma by age 6

BACKGROUND

Gut microbiota and intestinal inflammation regulate the development of immune-mediated diseases, such as allergies. Fecal calprotectin is a biomarker of intestinal inflammation.

OBJECTIVE

We evaluated the association of early-age fecal calprotectin levels to the later development of allergic diseases in children from farming and non-farming environments and further studied the effect of gut microbiota on the fecal calprotectin levels.

METHODS

Fecal calprotectin was measured from 758 infants participating in the PASTURE study at the age of 2 months using the ELISA method. Serum-specific IgE levels were measured at 6 years of age. Data of environmental factors, doctor-diagnosed atopic dermatitis (AD) and asthma were collected by questionnaire. Multivariate logistic regression models were used for analysis. The composition of fecal microbiota was analysed in a subgroup of 120 infants with 16S rRNA pyrosequencing. The effect of Escherichia coli lipopolysaccharide (LPS) on in vitro monocyte IL-10 secretion was studied by flow cytometry.

RESULTS

The infants with high fecal calprotectin levels at 2 months, that is above the 90th percentile, had an increased risk of developing AD and asthma/asthmatic bronchitis by the age of 6 years (aOR 2.02 (1.06-3.85) and 2.41 (1.25-4.64), respectively). High fecal calprotectin levels correlated negatively with fecal Escherichia. LPS from E. coli stimulated production of IL-10 in monocytes.

CONCLUSION AND CLINICAL RELEVANCE

High degree intestinal inflammation at 2 months of age, detected as high fecal calprotectin, predicted asthma and AD by the age of 6 years and was linked to low abundance of fecal Escherichia. Impaired IL-10 activation due to the lack of colonization with E. coli could explain the intestinal inflammation associated high fecal calprotectin and later risk of asthma and AD. Our results have implications for the design of probiotic treatments and suggest that early intestinal colonization has long-term health effects.

Macrophage phenotypes in the adipose tissue of postmenopausal women

Atherosclerosis pathology is the interplay between high intravascular LDL particle concentration and monocyte/macrophage presence within the sub-endothelial space of the artery. In this project, phenotypes of macrophages connected with subclinical inflammation in adipose tissue of living kidney donors were studied. Samples of subcutaneous adipose tissue of living kidney donors (n=36) were exposed to collagenase. Stromal vascular fraction (SVF) was eluted from the samples, then labeled with monoclonal antibodies (anti-CD14 and anti-calprotectin), conjugated with fluorochromes and analyzed by flow cytometry. The positive correlation between the number of total macrophages and calprotectin-positive macrophages with BMI in the subcutaneous adipose tissue of postmenopausal women was demonstrated (p<0.05; R=0.43 and p<0.01; R=0.60), whereas no positive correlation in premenopausal women and men was shown. In conclusion, we documented a significant effect of BMI increase on the presence of total macrophages in adipose tissue of postmenopausal women, in contrast to premenopausal women. This difference was much more pronounced when proinflammatory macrophages with membrane-bound calprotectin were analyzed.

Calprotectin and lactoferrin in the cerebrospinal fluid; biomarkers utilisable for differential diagnostics of bacterial and aseptic meningitis?

BACKGROUND

The aim of our work was to assess the diagnostic contribution of calprotectin and lactoferrin determinations in the cerebrospinal fluid when distinguishing between bacterial and aseptic meningitides.

METHODS

In 23 patients with bacterial meningitis (BM) and in 50 patients with aseptic meningitis (AM), we determined the concentrations of calprotectin, lactoferrin and the conventional biomarkers like glucose, total protein, lactate and polynuclear count in the cerebrospinal fluid (CSF). The discriminative power of the various parameters studied was determined by means of receiver operating characteristic (ROC) curves: the area under the curve (AUC), sensitivity, specificity, the positive likelihood ratio (+LR), and the negative likelihood ratio (-LR).

RESULTS

The diagnostic efficiency of calprotectin, lactoferrin, lactate, and polynuclear count when distinguishing between bacterial and aseptic meningitides, expressed by ROC curve parameters, was as follows: AUC (0.736, 0.946, 0.932, 0.932), sensitivity (86.2, 96.6, 90.0, 89.7), specificity (58.5, 92.4, 87.0, 90.6), +LR (2.08, 12.8, 6.9, 9.50), -LR (0.24, 0.04, 0.11, 0.11), respectively. The optimal cut point for calprotectin and lactoferrin was 191 ng/mL and 17.8 ng/mL, respectively.

CONCLUSIONS

Our findings show, that the determination of lactoferrin in the CSF was diagnostically the most efficient marker in distinguishing between bacterial and viral meningitides. Calprotectin was far less efficient diagnostic marker. The polynuclear count and lactate concentration showed a very good diagnostic efficiency as well. The determination of protein and glucose was diagnostically less beneficial.

Serum calprotectin--a promising diagnostic marker for adult-onset Still's disease

Calprotectin is a calcium-binding cytosolic protein, mainly expressed in immune cells, such as neutrophils, monocytes, and macrophages. Our study aimed to evaluate the diagnostic value of calprotectin for adult-onset Still’s disease (AOSD), by comparing serum calprotectin concentrations in patients with AOSD (n = 46), rheumatoid arthritis (RA, n = 34), primary Sjögren syndrome (pSS, n = 40), systemic lupus erythematosus (SLE, n = 39), osteoarthritis (OA, n = 20), and healthy controls (HCs, n = 49). Calprotectin concentrations were significantly higher in patients with AOSD (55.26 ± 18.00 ng/ml), compared to patients with RA (39.17 ± 18.90 ng/ml), pSS (35.31 ± 19.47 ng/ml), SLE (32.21 ± 25.01 ng/ml), OA (19.24 ± 10.67 ng/ml), and HCs (8.46 ± 5.17 ng/ml). All the differences were highly significant (p < 0.001). Using receiver-operating characteristic curve, the cut-off value of calprotectin was defined as 45.488 ng/ml, and its sensitivity and specificity for AOSD diagnosis were 63.0 and 80.1 %, respectively. The positive rate of calprotectin was significantly higher in AOSD cases compared to patients with other diseases and healthy controls (p < 0.001). Serum calprotectin was positively correlated with ferritin (r = 0.294, p < 0.05), and concentration of hemoglobin was significantly lower in calprotectin-positive patients compared to negative patients in AOSD (103.49 ± 20.21 g/l vs 115.71 ± 15.59 g/l, t = −2.142, p = 0.038). These findings suggest that serum calprotectin may serve as a promising marker for the diagnosis of AOSD and monitor disease activity to a certain extent.

A Novel Combination of Calprotectin and CXCL12 for Predicting Malignancy in Patients with Exudative Pleural Effusion

Pleural effusion (PE) remains a significant challenge and public health problem, which needs novel noninvasive biomarkers for the precise diagnosis. The aim of this study was to further determine the clinical efficacy and diagnostic accuracy of a novel combination of calprotectin and CXCL12 for predicting malignancy in patients with exudative PE.Calprotectin and CXCL12 concentrations were measured in 95 individuals of exudative PE, with 39 malignant PE (MPE) and 56 benign PE (BPE). The accuracy of calprotectin and CXCL12 levels for discriminating MPE from BPE or tuberculous PE were evaluated using receiver-operating characteristic (ROC) curves. Univariate and multivariate logistic regression analyses were performed to test the association between calprotectin and CXCL12 levels and MPE.Calprotectin and CXCL12 levels of patients with MPE were significantly lower than that of BPE and tuberculous PE (P < 0.05). The area under the curve (AUC) of calprotectin and CXCL12 was 0.683 and 0.641 in MPE and BPE, and a combination of calprotectin ≤500.19 ng/mL and CXCL12 ≤6.11 ng/mL rendered a sensitivity and specificity of 48.72% and 78.57%, respectively. While in MPE and tuberculous PE, the AUC of calprotectin and CXCL12 was 0.696 and 0.690, and a combination of calprotectin ≤421.73 ng/mL and CXCL12 ≤3.71 ng/mL presented a sensitivity and specificity of 25.64% and 95.45%, respectively. Multivariate logistic regression demonstrated that both calprotectin and CXCL12 were independent predictors of MPE.Calprotectin and CXCL12 in pleural fluid are informative diagnostic biomarkers for predicting patients with MPE.

Fecal calprotectin and its correlation with inflammatory markers and endoscopy in patients from India with inflammatory bowel disease

INTRODUCTION

In clinical practice, endoscopic findings are often used for assessing disease activity in inflammatory bowel disease (IBD). In recent years, blood and stool markers are being increasingly used for this purpose. Among them, the fecal calprotectin (FC) level is probably the most favored. Data on the reliability of FC are lacking from countries like India, where gut infections are common.

OBJECTIVE

The aims of this study were to compare the FC level with the erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) as non-invasive markers of IBD and, in patients with ulcerative colitis (UC), and to study its correlation with disease extent, clinical activity, and endoscopic severity.

METHODS

Records of patients with IBD who had tests for FC, ESR and CRP and colonoscopy done within a 2-week period, between 2012 and 2014, were retrieved. Sixty-three patients (UC 32, Crohn's disease [CD] 31) were included for analysis. ESR, CRP and FC were compared to endoscopy to assess inflammation.

RESULTS

Patients with UC had higher levels of FC than those with ileocolonic CD (median FC 800 mcg/g vs. 619 mcg/g, respectively; p = 0.04). FC levels correlated with CRP (r = 0.4, p < 0.001) but not with ESR (r = 0.21, p = 0.09). In patients with UC with endoscopic evidence of inflammation, more (86.9 %) had FC > 200 mcg/g (cut-off for disease activity in our laboratory) than had ESR >20 mm in the first hour (60.6 %) or positive CRP (65.6 %) (< 0.01); FC levels increased with increasing endoscopic Mayo score (p = 0.001) and Truelove-Witt's clinical severity score (p = 0.006), but did not correlate with disease extent (p = 0.7). The best FC cut-off level to identify 'active UC' (Mayo grade 2 or more) was 800 mcg/g.

CONCLUSION

Fecal calprotectin level correlates with CRP but not with ESR. In patients with UC with inflammation, FC > 200 mcg/g is more often positive than raised ESR or CRP; it also correlates with clinical and endoscopic activity but not with disease extent. FC level > 800 mcg/g can be used to differentiate active from inactive UC.

Biomarkers in Remission According to Different Criteria in Patients with Rheumatoid Arthritis

OBJECTIVE

Remission is the primary aim in the treatment of patients with rheumatoid arthritis (RA). In this study, we aimed to evaluate biomarker profiles of patients in remission by different criteria and compare these profiles with controls.

METHODS

Serum levels of calprotectin, interleukin 6 (IL-6), type II collagen helical peptide, C-terminal crosslinking telopeptide of type I collagen generated by matrix metalloproteinases (ICTP), matrix metalloproteinase 3 (MMP-3), resistin, and leptin were measured by ELISA in 80 patients. The patients were in Disease Activity Score at 28 joints with erythrocyte sedimentation rate (DAS28-ESR) remission, and had these characteristics: female/male 54/26, mean age 51.4 ± 12.1 years, mean disease duration 11.4 ± 8.1 years, rheumatoid factor positivity 68.7% (n = 55), anticyclic citrullinated peptide positivity 60.7% (n = 48). These patients were also evaluated for the American College of Rheumatology/European League Against Rheumatism (Boolean) and Simple Disease Activity Index (SDAI) remissions. Additionally, 80 age-, sex-, and comorbidity-matched individuals without rheumatic diseases were included in the study as controls.

RESULTS

At recruitment of 80 patients in DAS28 remission, 33 patients (41.2%) were found in Boolean remission and 39 patients (48.7%) were in SDAI remission. Serum MMP-3, ICTP, resistin, and IL-6 levels of the 80 patients in DAS28 remission were statistically significantly higher than the controls. Patients in Boolean and SDAI remissions had significantly higher serum ICTP, resistin, and IL-6 levels in comparison with the controls.

CONCLUSION

The 3 commonly used remission criteria of RA are almost similar with regard to patients' biomarker levels. Biomarker profiles of patients may provide complementary information to clinical evaluation of remission and may help to determine the patients under the risk of progression.

Characterization of the Leukocyte Response in Acute Vocal Fold Injury

Macrophages location in the superficial layer of the vocal fold (VF) is not only at the first line of defense, but in a place of physiologic importance to voice quality. This study characterizes and compares macrophage function in two models of acute injury. Porcine VF injuries were created bilaterally by either surgical biopsy or lipopolysaccharide (LPS) (1.5μg/kg) injection. Animals were sacrificed at 1- or 5-day post LPS or 3-, 7-, or 23-days post-surgical injury (n = 3/time/ injury). Flow cytometry characterized immunophenotypes and RT-PCR quantified cytokine gene expression. Uninjured VF were used as controls. Post-surgical and LPS injury, SWC9+/SWC3- cells identified as hi SLA-DR+ (p<0.05) compared to controls along with hi CD16+ expression at 1-day and 3-days respectively compared to all other time points (p<0.05). Surgical injuries, SWC9+/SWC3- cells exhibited hi CD163+ (p<0.05) at 3-days along with upregulation in TNFα and TGFβ1 mRNA compared to 23-days (p<0.05). No measurable changes to IL–12, IFNγ, IL–10, IL–4 mRNA post-surgery. LPS injuries induced upregulation of TNFα, IL–12, IFNγ, IL–10, and IL–4 mRNA at 1- and 5-days compared to controls (p<0.05). Higher levels of IL–10 mRNA were found 1-day post-LPS compared to 5-days (p<0.05). No changes to CD163 or CD80/86 post-LPS were measured. Acute VF injuries revealed a paradigm of markers that appear to associate with each injury. LPS induced a regulatory phenotype indicated by prominent IL–10 mRNA expression. Surgical injury elicited a complex phenotype with early TNFα mRNA and CD163+ and persistent TGFβ1 transcript expression.

Markers of bacterial translocation in end-stage liver disease

Bacterial translocation (BT) refers to the passage of viable bacteria or bacterial products from the intestinal lumen, through the intestinal epithelium, into the systemic circulation and extraintestinal locations. The three principal mechanisms that are thought to be involved in BT include bacterial overgrowth, disruption of the gut mucosal barrier and an impaired host defence. BT is commonly observed in liver cirrhosis and has been shown to play an important role in the pathogenesis of the complications of end stage liver disease, including infections as well as hepatic encephalopathy and hepatorenal syndrome. Due to the importance of BT in the natural history of cirrhosis, there is intense interest for the discovery of biomarkers of BT. To date, several such candidates have been proposed, which include bacterial DNA, soluble CD14, lipopolysaccharides endotoxin, lipopolysaccharide-binding protein, calprotectin and procalcitonin. Studies on the association of these markers with BT have demonstrated not only promising data but, oftentimes, contradictory results. As a consequence, currently, there is no optimal marker that may be used in clinical practice as a surrogate for the presence of BT.

Serum calprotectin (S100A8/9): an independent predictor of ultrasound synovitis in patients with rheumatoid arthritis

Introduction

Calprotectin, a heterodimeric complex of S100A8/9 (MRP8/14), has been proposed as an important serum biomarker that reflects disease activity and structural joint damage in rheumatoid arthritis (RA). The objective of this cross-sectional study was to test the hypothesis that calprotectin is associated with clinical and ultrasound-determined disease activity in patients with RA.

Methods

A total of 37 patients with RA (including 24 females, a mean disease duration of 20 months) underwent a clinical examination and 7-joint ultrasound score (German US-7) of the clinically dominant hand and foot to assess synovitis by grey-scale (GS) and synovial vascularity by power Doppler (PD) ultrasound using semiquantitative 0–3 grading. The levels of serum calprotectin and C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were determined at the time of the ultrasound assessment. We analysed the relationship between serum calprotectin level, traditional inflammatory markers, and ultrasound-determined synovitis.

Results

The levels of serum calprotectin were significantly correlated with swollen joint count (r = 0.465, p < 0.005), DAS28-ESR (r = 0.430, p < 0.01), ESR (r = 0.370, p < 0.05) and, in particular, CRP (r = 0.629, p < 0.001). Calprotectin was significantly associated with GS (r = 0.359, p < 0.05) and PD synovitis scores (r = 0.497, p < 0.005). Using multivariate regression analysis, calprotectin, adjusted for age and sex, was a better predictor of PD synovitis score (R² = 0.765, p < 0.001) than CRP (R² = 0.496, p < 0.001).

Conclusions

The serum levels of calprotectin are significantly associated with clinical, laboratory and ultrasound assessments of RA disease activity. These results suggest that calprotectin might be superior to CRP for monitoring ultrasound-determined synovial inflammation in RA patients.

Myeloid-related protein 8 induces self-tolerance and cross-tolerance to bacterial infection via TLR4- and TLR2-mediated signal pathways

Myeloid-related protein 8 (Mrp8) is the active component of Mrp8/14 protein complex released by phagocytes at the site of infection and stimulates inflammatory responses. However, it is unclear whether Mrp8 could induce self-tolerance and cross-tolerance to bacterial infection. Here we report that Mrp8 triggered TNF-α and IL-6 release via a Toll-like receptor 4 (TLR4)-dependent manner. Pre-stimulation of murine macrophages and human monocytes with Mrp8 induced self-tolerance to Mrp8 re-stimulation and cross-tolerance to lipopolysaccharide (LPS), bacterial lipoprotein (BLP), gram-negative and gram-positive bacterial challenges, with substantially attenuated TNF-α and IL-6 release. Moreover, Mrp8 tolerisation significantly reduced serum TNF-α and IL-6, increased polymorphonuclear neutrophil (PMN) recruitment and accelerated bacterial clearance, thus protecting mice against LPS-induced lethality and cecal ligation and puncture (CLP)-induced polymicrobial sepsis. In addition to TLR4, TLR2 also contributed to Mrp8-induced inflammatory response and tolerance. Down-regulation of phosphorylated p38 by Mrp8 pre-stimulation was predominantly responsible for the intracellular mechanism of Mrp8-induced tolerance. Thus, our findings of Mrp8-induced self-tolerance and cross-tolerance may provide a potential strategy for attenuating an overwhelming proinflammatory cascade and enhancing antimicrobial responses during microbial sepsis.

Neutrophil Extracellular Traps in Ulcerative Colitis: A Proteome Analysis of Intestinal Biopsies

BACKGROUND

The etiology of the inflammatory bowel diseases, including ulcerative colitis (UC), remains incompletely explained. We hypothesized that an analysis of the UC colon proteome could reveal novel insights into the disease etiology.

METHODS

Mucosal colon biopsies were taken by endoscopy from noninflamed tissue of 10 patients with UC and 10 controls. The biopsies were either snap-frozen for protein analysis or prepared for histology. The protein content of the biopsies was characterized by high-throughput gel-free quantitative proteomics, and biopsy histology was analyzed by light microscopy and confocal microscopy.

RESULTS

We identified and quantified 5711 different proteins with proteomics. The abundance of the proteins calprotectin and lactotransferrin in the tissue correlated with the degree of tissue inflammation as determined by histology. However, fecal calprotectin did not correlate. Forty-six proteins were measured with a statistically significant differences in abundances between the UC colon tissue and controls. Eleven of the proteins with increased abundances in the UC biopsies were associated with neutrophils and neutrophil extracellular traps. The findings were validated by microscopy, where an increased abundance of neutrophils and the presence of neutrophil extracellular traps by extracellular DNA present in the UC colon tissue were confirmed.

CONCLUSIONS

Neutrophils, induced neutrophil extracellular traps, and several proteins that play a part in innate immunity are all increased in abundance in the morphologically normal colon mucosa from patients with UC. The increased abundance of these antimicrobial compounds points to the stimulation of the innate immune system in the etiology of UC.

The marker C-reactive protein is helpful in monitoring the integrity of anastomosis: plasma calprotectin

BACKGROUND

Despite improved surgical techniques and materials, anastomotic leakage is a big problem for surgeons. The most frequently used laboratory parameters is leukocyte (white blood cell) and C-reactive protein (CRP). Availability of plasma calprotectin with CRP to detect anastomotic leakage was studied.

METHODS

In this prospective study of 41 (male/female 18/23) patients in the anastomosis group, 30 (male/female 20/10) patients were included in the control group. The anastomosis groups viewed in preoperatively day and postoperatively 1st, 3rd, and 5th day of CRP, white blood cell, and plasma calprotectin values.

RESULTS

Anastomosis group with complications and without complications were studied. Statistically significant similarities between plasma calprotectin and CRP levels in the postoperative period were observed.

CONCLUSION

Plasma calprotectin in monitoring the integrity of the anastomosis can be used with a marker CRP.

A new turbidimetric immunoassay for serum calprotectin for fully automatized clinical analysers

Serum and plasma calprotectin concentration is shown to be elevated when neutrophils are activated, and may therefore be used as a marker for inflammatory diseases. A serum calprotectin immunoassay was developed based on calprotectin values observed in samples from the intensive care unit. The polyclonal avian antibodies were raised and affinity purified with calprotectin antigens. The performance was tested and it was observed that the assay was linear in the range 0.3-24.7 mg/L, the limit of quantitation was observed to be lower than 0.3 mg/L, no antigen excess was observed up to 54 mg/L, all CVs were lower than 1.8 % in the precision study, the calibration curve stability was longer than 6 weeks, and there was no significant interference detected for haemoglobin, intralipid or bilirubin. The serum calprotectin immunoassay presented in this paper performs well within the criteria carefully set from the limited clinical experience obtained in both serum and plasma. In addition it is commutable with Bühlmann MRP8/14 ELISA.

Methods to determine intestinal permeability and bacterial translocation during liver disease

Liver disease is often times associated with increased intestinal permeability. A disruption of the gut barrier allows microbial products and viable bacteria to translocate from the intestinal lumen to extraintestinal organs. The majority of the venous blood from the intestinal tract is drained into the portal circulation, which is part of the dual hepatic blood supply. The liver is therefore the first organ in the body to encounter not only absorbed nutrients, but also gut-derived bacteria and pathogen associated molecular patterns (PAMPs). Chronic exposure to increased levels of PAMPs has been linked to disease progression during early stages and to infectious complications during late stages of liver disease (cirrhosis). It is therefore important to assess and monitor gut barrier dysfunction during hepatic disease. We review methods to assess intestinal barrier disruption and discuss advantages and disadvantages. We will in particular focus on methods that we have used to measure increased intestinal permeability and bacterial translocation in experimental liver disease models.

In solution cation-induced secondary and tertiary structure alterations of human calprotectin

Calprotectin (CP) is widely considered to have diverse roles including growth inhibitory and apoptosis induction in a number of tumor cell lines and antimicrobial activities. As CP has been proposed to bind metal ions with high affinity, we have studied its functional and primarily its structural behavior upon Zn(2+) and Mn(2+) chelation solely and along with Ca(2+). We employed fluorescence spectroscopy and circular dichroism to determine the resulting modifications. Based upon our findings it is clear that treating CP with ions effectively weakened its natural growth inhibitory activity. Moreover, structural analysis of Zn(2+) and Mn(2+)-treated CPs indicated remarkable alterations in the regular secondary structures in favor of irregular structures while Zn(2+) and Mn(2+) treatment of CP after incubation with Ca(2+) displayed no remarkable shifts. Tertiary structure investigation using fluorescence spectroscopy showed that CP undergoes conformational changes upon Zn(2+) and Mn(2+) treatment whereby Trp residues of protein is slightly exposed to the hydrophilic environment, compactness of CP is compromised, whereas in Ca(2+)-treated CP, the tertiary structure integrity is intact upon Zn(2+) and Mn(2+) chelation. Interestingly, CP structural modifications upon Zn(2+) and Mn(2+) treatment was significantly comparable, probably due to similar radii and charges of ions. Taken all together, we have concluded that CP maintains its normal nature in Ca(2+)-loaded state when treated with Zn(2+) and Mn(2+) ions. It can be suggested that Ca(2+) not only stabilize CP structure but also helps CP to keep its structure upon metal ions chelation which is involved in host organism defense system.

Elevated serum levels of calprotectin (myeloid-related protein 8/14) in patients with ankylosing spondylitis and its association with disease activity and quality of life

BACKGROUND

Calprotectin is one of the major leukocyte S100 proteins showing both calcium binding and antimicrobial characteristics. The serum level of calprotectin is markedly elevated in patients with inflammatory bowel disease, rheumatoid arthritis, as well as systemic lupus erythematosus and has been suggested to play a prominent role in both progression and pathogenesis of these diseases.

AIM

The purpose of this study was to investigate the serum level of calprotectin in patients with ankylosing spondylitis (AS) and its association with disease activity and other clinical characteristics of AS.

MATERIALS AND METHODS

Thirty-one patients who met the modified New York criteria for AS and 45 healthy controls were included in this study. Both Bath AS disease activity index and AS disease activity score were applied on the patients with AS for the assessment of disease activity; Bath AS functional index, for the assessment of functional activity; Bath AS radiology index, for the assessment of radiological damage; and the AS quality of life questionnaire for the assessment of disease-related life status. Spinal and hip measurements were performed using Bath AS metrology index. The serum level of calprotectin was determined using enzyme-linked immunosorbent assay kit.

RESULTS

Mean serum level of calprotectin was significantly higher in the patients with AS compared with healthy controls (P = 0.003). Serum levels of calprotectin did not correlate with Bath AS disease activity index, AS disease activity score, Bath AS functional index, Bath AS radiology index, Bath AS metrology index, modified Schober, chest expansion, AS quality of life questionnaire, erythrocyte sedimentation rate, and C-reactive protein values (P > 0.05).

CONCLUSIONS

Our results suggest that calprotectin might play an important role in the pathogenetic mechanisms of AS; however, the calprotectin levels did not correlate with the measurements of disease activity, functional abilities, radiological damage, and the quality of life in these patients. Further insight into this area of research might provide opportunities to develop novel treatment strategies, which take into account the role of these peptides in the pathogenetic mechanisms of AS.

Fecal calprotectin use in inflammatory bowel disease and beyond: A mini-review

Given the number of inflammatory disorders affecting the gastrointestinal tract directly and indirectly, coupled with the considerable overlap with functional disorders, it is evident that more useful noninvasive diagnostic tests are required to aid with diagnosis. If these tests can also have some utility for individual patient follow-up in terms of disease activity and response to treatment, as well as providing forewarning of disease relapse, it would be extremely useful information for the clinician. One recently described test that may fulfill several of these attributes is based on leakage of a mononuclear cell cytoplasmic protein, calprotectin, along the intestinal tract, which can then be quantified in feces. This has been used to distinguish patients exhibiting symptoms of irritable bowel syndrome from patients with inflammatory bowel disease, with a measure of success greater than with currently used techniques. The present article summarizes the experience with this test used in inflammatory bowel disease, as well as a variety of gastrointestinal disorders.

Fecal calprotectin and ulcerative colitis endoscopic activity index as indicators of mucosal healing in ulcerative colitis

Ulcerative colitis (UC) is a chronic, idiopathic, inflammatory large bowel disease with recurrent variable periods of exacerbation. The aim of the current study is to evaluate the correlation of UCEIS with fecal calprotectin (FC) level to assess disease activity in UC patients in order to determine whether FC can prognosticate clinical outcome and disease activity of UC instead of colonoscopic evaluation. Our endoscopic investigations revealed the extension of UC as the following: proctitis (11.6%), procto-sigmoiditis (18.5%), left-sided colitis (15.8%), extensive colitis (11.7%), and normal endoscopy (42.4%). Conclusively, we suggest that FC can be used as a reliable tool to evaluate disease activity in ulcerative colitis patients. Moreover, our findings indicate a significant correlation between FC level and mucosal healing.

High faecal calprotectin levels in intestinal tuberculosis are associated with granulomas in intestinal biopsies

BACKGROUND

The diagnosis of intestinal tuberculosis (ITB) is sometimes difficult to establish and requires endoscopic investigation with biopsies for histopathological examination. This study aimed to evaluate calprotectin as a marker of inflammation in ITB.

METHODS

Patients with ITB were prospectively recruited in Southern India from October 2009 until July 2012. Demographic, clinical, endoscopic and histological features were examined along with faecal calprotectin (FC), serum calprotectin (SC) and C-reactive protein (CRP).

RESULTS

Thirty patients (median age 34.5 years, 19 men) were included. Clinical features were abdominal pain (97%), weight loss (83%), cachexia (75%), fatigue (63%), watery diarrhoea (62%), nausea (55%) and fever (53%). Endoscopy showed transverse ulcers (61%), nodularity of mucosa (55%), aphthous ulcers (39%), strictures (10%) and fissures (10%). The terminal ileum and right colon harboured 81% of the lesions. Histology revealed granulomas in biopsies from 10 of the patients. FC and CRP levels showed a strong positive correlation (rs = 0.70, p < 0.01). FC, SC and CRP levels were higher in the granulomatous than the non-granulomatous patients, respectively (median FC 988 μg/g, interquartile range (IQR) 940 vs 87 μg/g, IQR 704, p < 0.01; median SC 8.2 μg/ml, IQR 7.3 vs 3.8 μg/ml, IQR 8.9, p = 0.23; median CRP 38.8 mg/L, IQR 42.9 vs 2.3 mg/L, IQR 13.5, p < 0.01). Higher median calprotectin and CRP levels were detected in patients with extensive than localized disease, but the differences did not reach statistical significance.

CONCLUSION

ITB patients with granulomas on histology have high levels of faecal calprotectin and CRP.

Faecal calprotectin levels differentiate intestinal from pulmonary tuberculosis: An observational study from Southern India

BACKGROUND

Current methods to establish the diagnosis of intestinal tuberculosis are inadequate.

OBJECTIVES

We aimed to determine the clinical features of intestinal tuberculosis and evaluate inflammatory biomarkers in intestinal as well as pulmonary tuberculosis.

METHODS

We recruited 38 intestinal tuberculosis patients, 119 pulmonary tuberculosis patients and 91 controls with functional gastrointestinal disorders between October 2009 and July 2012 for the investigation of clinical features, C-reactive protein (CRP), faecal and serum calprotectin. Faecal calprotectin ≥200 µg/g was used as a cut-off to determine intestinal inflammation of clinical significance. Three patient categories were established: (a) pulmonary tuberculosis and faecal calprotectin <200 µg/g (isolated pulmonary tuberculosis); (b) pulmonary tuberculosis and faecal calprotectin ≥200 µg/g (combined pulmonary and intestinal tuberculosis); (c) isolated intestinal tuberculosis.

RESULTS

Common clinical features of intestinal tuberculosis were abdominal pain, fatigue, weight loss and watery diarrhoea. Intestinal tuberculosis patients had elevated median CRP (10.7 mg/l), faecal calprotectin (320 µg/g) and serum calprotectin (5.7 µg/ml). Complete normalisation of CRP (1.0 mg/L), faecal calprotectin (16 µg/g) and serum calprotectin (1.4 µg/ml)) was seen upon clinical remission. Patients with combined pulmonary and intestinal tuberculosis had the highest levels of CRP (53.8 mg/l) and serum calprotectin (6.5 µg/ml) and presented with signs of more severe disease.

CONCLUSION

Calprotectin analysis reveals intestinal tuberculosis in patients with pulmonary tuberculosis and pinpoints those in need of rigorous follow-up.

Clinical trials of yeast-derived β-(1,3) glucan in children: effects on innate immunity

BACKGROUND

The role of glucan in the stimulation of immune reactions is well established. In our report, we focused on the effects of orally administered glucan on nonspecific immunity of children with chronic respiratory problems.

MATERIALS AND METHODS

We measured the levels of albumin, lysozyme. C-reactive protein (CRP) and calprotectin in the saliva of 60 children ages 8-12 years and evaluated the effects of 30-day treatment with 100 mg/d oral dose of glucan.

RESULTS

We found a significant increase in the production of lysozyme, CRP and calprotectin in glucan-treated children.

CONCLUSIONS

Short-term oral application of natural immunomodulator β-glucan significantly stimulated mucosal immunity of children with chronic respiratory problems.

Fecal calprotectin concentration in neonatal necrotizing enterocolitis

PURPOSE

Among the many factors associated with acute intestinal mucosal infection, numerous studies have proposed the usefulness of fecal calprotectin. The aim of this study was to evaluate the usefulness of fecal calprotectin in the diagnosis of necrotizing enterocolitis (NEC).

METHODS

We collected 154 stool samples from 16 very low birth weight and premature newborns at the Konyang University Hospital neonatal intensive care unit or neonatal nursery. The stool samples were collected using the Calprest device, and the fecal calprotectin level was measured with the BÜHLMANN Calprotectin enzyme-linked immunosorbent assay kit.

RESULTS

Fecal calprotectin levels were significantly higher in the NEC group than in the non-NEC group (P=0.02). There was a significant positive linear relationship between the fecal calprotectin level and number of days after birth (P=0.00) in the gestational age <26 weeks group. There was a significant negative linear relationship between the calprotectin level and number of days after birth (P=0.03) in the gestational age ≥26 weeks and <30 weeks group. There was no difference in the calprotectin levels according to the type and method of feeding between the NEC and non-NEC groups.

CONCLUSION

Fecal calprotectin levels were significantly increased in premature infants with NEC. The fecal calprotectin test is a noninvasive, easy, and useful tool for the diagnosis of NEC.

Increased faecal calprotectin predicts recurrence of colonic diverticulitis

BACKGROUND AND AIMS

Colonic diverticulitis shows a high recurrence rate, but the role of faecal markers in predicting recurrence is unknown. The aim of this study was to investigate the role of faecal calprotectin (FC) in predicting recurrence of diverticulitis.

PATIENTS/METHODS

A prospective cohort study was performed on 54 patients suffering from acute uncomplicated diverticulitis (AUD) diagnosed by computerized tomography (CT). After remission, patients underwent to clinical follow-up every 2 months. After remission and during the follow-up, FC was analysed. Recurrence of diverticulitis was defined as return to our observation due to left lower-quadrant pain with or without other symptoms (e.g. fever), associated with leucocytosis and/or increased C-reactive protein (CRP). Presence of diverticulitis was confirmed by means of CT.

RESULTS/FINDINGS

The mean follow-up was 20 months (range 12-24 months). Forty-eight patients were available for the final evaluation, and six patients were lost to follow-up. During follow-up, increased FC was detected in 17 (35.4 %) patients and diverticulitis recurred in eight patients (16.7 %). Diverticulitis recurred in eight (16.7 %) patients: seven (87.5 %) patients showed increased FC during the follow-up, and only one (12.5 %) patient with recurrent diverticulitis did not show increased FC. Diverticulitis recurrence was strictly related to the presence of abnormal FC test during follow-up.

CONCLUSIONS

In the present prospective study, increased FC was found to be predictive of diverticulitis recurrence.

Calprotectin induces cell death in human prostate cancer cell (LNCaP) through survivin protein alteration

Calprotectin (CP), an abundant heterodimeric cytosolic protein of neutrophils, conveys a variety of functions such as tumor cell growth arrest and antimicrobial activity. We investigated CP activity and its possible apoptosis-inducing mechanism of action against an antiandrogen therapy-resistance prostate cancer cell line LNCaP. Cell viability and Annexin V FITC assays were performed in order to investigate its cell death activity and apoptosis, respectively. In order to address cell death inducing mechanism(s), immunocytochemistry and immunobloting analysis, reactive oxygen species (ROS) and nitric oxide (NO) measurements were performed. The effective concentration of CP against LNCaP promoting LNCaP cell death was 200 µg/mL. ROS and NO levels of cells remarkably were enhanced following treatment with 50 and 100 µg/mL of CP, respectively. Protein expression of anti-apoptotic protein survivin was significantly decreased after administration of tumor cells with CP. Our data indicate that CP regulates the LNCaP cells viability via survivin-mediated pathway and ROS and NO enhancement. Thus, inhibition of survivin expression, enhancement of ROS and NO level by CP or other similar pharmaceutical agents might be effective in lowering the malignant proliferation of human prostate cancer cells.

Faecal calprotectin and lactoferrin as markers for monitoring disease activity and predicting clinical recurrence in patients with Crohn's disease after ileocolonic resection: A prospective pilot study

BACKGROUND

Several studies have reported that faecal calprotectin and lactoferrin showed a close correlation with endoscopic inflammation in patients with inflammatory bowel disease. However, the clinical significance of faecal calprotectin or lactoferrin in postoperative Crohn's disease (CD) is not fully evaluated. This prospective study was to investigate the relationship between endoscopic activity, and faecal calprotectin and lactoferrin, and assess the predictive value of these markers for future recurrence.

METHODS

Twenty patients who remained in remission during 6-12 months after ileocolonic resection for CD were included. All patients underwent ileocolonoscopy for assessing endoscopic activity (Rutgeerts score) in the neo-terminal ileum. A stool sample was collected for measurement of calprotectin and lactoferrin. All patients were then followed up for 12 months, and clinical recurrence was defined as a CDAI >150 with an increase of ≥70 points.

RESULTS

The mean time between surgery and the endoscopic examination at entry was 7.2 months. The endoscopic scores were i0 or i1 in 10 patients, i2 in six patients, i3 in three patients, and i4 in one patient. Both calprotectin and lactoferrin positively correlated with the endoscopic scores (p = 0.0001 and p = 0.038, respectively). Six patients developed clinical recurrence during the 12-month follow-up. Both calprotectin and lactoferrin levels were significantly higher in patients with clinical recurrence than those in remission (p = 0.0007 and p = 0.025, respectively). A cutoff value of 170 µg/g for calprotectin had a sensitivity of 83% and a specificity of 93% to predict a risk of clinical recurrence, while a cutoff value of 140 µg/g for lactoferrin had a sensitivity of 67% and a specificity of 71%.

CONCLUSIONS

Both calprotectin and lactoferrin levels correlate well with endoscopic activity after ileocolonic resection for CD. Calprotectin and lactoferrin could be clinically relevant biomarkers for predicting postoperative recurrence. Further well-designed large trials should strengthen the findings of the present investigation.

Comparison of three tests for faecal calprotectin in children and young adults: a retrospective monocentric study

OBJECTIVE

Faecal calprotectin is used as a sensitive marker for gastrointestinal mucosal inflammation. We compared the performance of three different assays in a large cohort of symptomatic paediatric patients.

DESIGN

Retrospective monocentric study.

SETTING

Inpatients and outpatients of a tertiary referral centre for paediatric gastroenterology.

PARTICIPANTS

304 symptomatic patients (163 males, aged 2-20 years) with active inflammatory bowel disease (IBD/A, n=130), IBD in clinical remission (IBD/R, n=62), other intestinal diseases (n=45) and controls without identified intestinal disease (n=67).

INTERVENTIONS

Calprotectin was measured in homogenised faecal samples with three tests (A: EliA Calprotectin, Phadia AB, Sweden; B: PhiCal, Calpro AS, Norway; C: EK-Cal, Bühlmann Laboratories, Switzerland).

OUTCOMES

Concordance between tests was calculated using Kendall's τ coefficient.

RESULTS

IBD/A and controls were correctly classified as 97.7%/82.1% (A), 97.7%/85.1% (B) and 98.4%/62.7% (C; not significant). Test C tended to have higher calprotectin values with a lower specificity compared to tests A and B. The concordance between two tests was 0.835 for tests A and B, 0.782 for tests A and C and 0.765 for tests B and C.

CONCLUSIONS

All three tests are very sensitive for detecting mucosal inflammation, but major differences exist between specificity and absolute values. It is highly advisable to use the test of the same manufacturer for follow-up and to monitor for disease activity.

Effect of large colon ischemia and reperfusion on concentrations of calprotectin and other clinicopathologic variables in jugular and colonic venous blood in horses

OBJECTIVE

To determine the effect of large colon ischemia and reperfusion on concentrations of the inflammatory neutrophilic protein calprotectin and other clinicopathologic variables in jugular and colonic venous blood in horses.

ANIMALS

6 healthy horses.

PROCEDURES

Horses were anesthetized, and ischemia was induced for 1 hour followed by 4 hours of reperfusion in a segment of the pelvic flexure of the large colon. Blood samples were obtained before anesthesia, before induction of ischemia, 1 hour after the start of ischemia, and 1, 2, and 4 hours after the start of reperfusion from jugular veins and veins of the segment of the large colon that underwent ischemia and reperfusion. A sandwich ELISA was developed for detection of equine calprotectin. Serum calprotectin concentrations and values of blood gas, hematologic, and biochemical analysis variables were determined.

RESULTS

Large colon ischemia caused metabolic acidosis, a significant increase in lactate and potassium concentrations and creatine kinase activities, and a nonsignificant decrease in glucose concentrations in colonic venous blood samples. Values of these variables after reperfusion were similar to values before ischemia. Ischemia and reperfusion induced activation of an inflammatory response characterized by an increase in neutrophil cell turnover rate in jugular and colonic venous blood samples and calprotectin concentrations in colonic venous blood samples.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of this study suggested that large colon ischemia and reperfusion caused local and systemic inflammation in horses. Serum calprotectin concentration may be useful as a marker of this inflammatory response.

Fecal calprotectin and lactoferrin as predictors of relapse in patients with quiescent ulcerative colitis during maintenance therapy

PURPOSE

This prospective study was to evaluate the significance of fecal calprotectin and lactoferrin for the prediction of ulcerative colitis (UC) relapse.

METHODS

Eighty UC patients in remission for ≥3 months on mesalamine as maintenance therapy were included. At entry, stool samples were collected for the measurement of calprotectin and lactoferrin. All patients were followed up for the following 12 months. To identify predictive factors for relapse, time-dependent analyses using the Kaplan-Meier graphs and Cox's proportional hazard model were applied.

RESULTS

During the 12 months, 21 patients relapsed. Mean calprotectin and lactoferrin levels were significantly higher in patients with relapse than those in remission (calprotectin-173.7 vs 135.5 μg/g, P = 0.02; lactoferrin-165.1 vs 130.7 μg/g, P = 0.03). A cutoff value of 170 μg/g for calprotectin had a sensitivity of 76 % and a specificity of 76 % to predict relapse, while a cutoff value of 140 μg/g for lactoferrin had a sensitivity of 67 % and a specificity of 68 %. In a multivariate analysis, calprotectin (≥170 μg/g) was a predictor of relapse (hazard ratio, 7.23; P = 0.002). None of the following parameters were significantly associated with relapse: age, gender, duration of UC, number of UC episode, severity of the previous episode, extent of UC, extraintestinal manifestation, and lactoferrin level.

CONCLUSIONS

Fecal calprotectin showed a higher sensitivity and specificity than fecal lactoferrin for predicting UC relapse. Fecal calprotectin level appeared to be a significant predictor of relapse in patients with quiescent UC on mesalamine as maintenance therapy.

Advances in the diagnosis and management of inflammatory bowel disease: challenges and uncertainties

Over the past two decades, several advances have been made in the management of patients with inflammatory bowel disease (IBD) from both evaluative and therapeutic perspectives. This review discusses the medical advancements that have recently been made as the standard of care for managing patients with ulcerative colitis (UC) and Crohn's Disease (CD) and to identify the challenges associated with implementing their use in clinical practice. A comprehensive literature search of the major databases (PubMed and Embase) was conducted for all recent scientific papers (1990-2013) giving the recent updates on the management of IBD and the data were extracted. The reported advancements in managing IBD range from diagnostic and evaluative tools, such as genetic tests, biochemical surrogate markers of activity, endoscopic techniques, and radiological modalities, to therapeutic advances, which encompass medical, endoscopic, and surgical interventions. There are limited studies addressing the cost-effectiveness and the impact that these advances have had on medical practice. The majority of the advances developed for managing IBD, while considered instrumental by some IBD experts in improving patient care, have questionable applications due to constraints of cost, lack of availability, and most importantly, insufficient evidence that supports their role in improving important long-term health-related outcomes.

Fecal calprotectin in healthy children

Calprotectin is a protein found in the cytosol of inflammatory cells and is a marker of the presence and the degree of inflammation in the bowel system. Calprotectin in feces has great diagnostic value in the matter of inflammatory bowel disease (IBD). In feces, the protein is stable up to seven days, and since the protein can easily be measured with an ELISA, the use of fecal calprotectin (FC) means no invasive measures. For adults and children over 4 years, a cut-off level of 50 mg/kg has been well established for diagnostic purposes. Because previous studies have proven that children under the age of four in general have higher FC values than older children and adults, there is a need for a cut-off level for this age group. In order to establish that, the normal values for FC in children from 0-4 years were investigated. Some 75 stool samples from healthy children were collected and the levels of FC were analyzed. The results were compared to 157 pediatric cases where FC analysis had been performed for diagnostic purposes. As a result, three cut-off levels were established based on the 97.5% percentiles of FC in different age groups: 538 mg/kg (1 < 6 months), 214 mg/kg (6 months < 3 years) and 75 mg/kg (3 < 4 years).

Serum calprotectin levels in elderly males and females without bacterial or viral infections

OBJECTIVES

Calprotectin is released from activated leukocytes and calprotectin can thus be used as a marker for leukocyte activation. Faeces calprotectin is not only used as a marker for inflammatory bowel disease but can also be used to detect leukocyte activation in other body fluids. The aim of the present study was to study serum calprotectin levels in non-infected elderly individuals to establish reference intervals for the marker.

METHODS

Serum calprotectin was analyzed by immunoturbidimetry in 75 year old females and males without known infections. Individuals with CRP>20mg/L were excluded as this could indicate a subclinical infection. The calprotectin levels in the remaining 713 individuals were used to calculate reference values for this population. The Spearman rank correlations between calprotectin and 27 other laboratory biomarkers were also investigated.

RESULTS

There was a strong positive Spearman rank correlation between calprotectin and CRP (p<0.000001) and alkaline phosphatase (p<0.000001). There were also significant negative correlations between calprotectin and ApoA1 and direct HDL-cholesterol.

CONCLUSIONS

The reference interval for serum-calprotectin for all study subjects was 0.3-2.6 mg/L. Leukocyte alkaline phosphatase contributes to serum alkaline phosphatase levels.

S100A8/A9 as a biomarker for synovial inflammation and joint damage in patients with rheumatoid arthritis

S100A8 and S100A9 are major leukocyte proteins, known as damage-associated molecular patterns, found at high concentrations in the synovial fluid of patients with rheumatoid arthritis (RA). A heterodimeric complex of S100A8/A9 is secreted by activated leukocytes and binds to Toll-like receptor 4, which mediates downstream signaling and promotes inflammation and autoimmunity. Serum and synovial fluid levels of S100A8/A9 are markedly higher in patients with RA than in patients with osteoarthritis or miscellaneous inflammatory arthritis. Serum levels of S100A8/A9 are significantly correlated with clinical and laboratory markers of inflammation, such as C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, and the Disease Activity Score for 28 joints. Significant correlations have also been found between S100A8/A9 and radiographic and clinical assessments of joint damage, such as hand radiographs and the Rheumatoid Arthritis Articular Damage score. In addition, among known inflammatory markers, S100A8/A9 has the strongest correlation with total sum scores of ultrasonography assessment. Furthermore, baseline levels of S100A8/A9 are independently associated with progression of joint destruction in longitudinal studies and are responsive to change during conventional and biologic treatments. These findings suggest S100A8/A9 to be a valuable diagnostic and prognostic biomarker for RA.

Serum albumin and body weight as biomarkers for the antemortem identification of bone and gastrointestinal disease in the common marmoset

The increasing use of the common marmoset (Callithrix jacchus) in research makes it important to diagnose spontaneous disease that may confound experimental studies. Bone disease and gastrointestinal disease are two major causes of morbidity and mortality in captive marmosets, but currently no effective antemortem tests are available to identify affected animals prior to the terminal stage of disease. In this study we propose that bone disease and gastrointestinal disease are associated disease entities in marmosets and aim to establish the efficacy of several economical antemortem tests in identifying and predicting disease. Tissues from marmosets were examined to define affected animals and unaffected controls. Complete blood count, serum chemistry values, body weight, quantitative radiographs, and tissue-specific biochemical markers were evaluated as candidate biomarkers for disease. Bone and gastrointestinal disease were associated, with marmosets being over seven times more likely to have either concurrent bone and gastrointestinal disease or neither disease as opposed to lesions in only one organ system. When used in tandem, serum albumin <3.5 g/dL and body weight <325 g identified 100% of the marmosets affected with concurrent bone and gastrointestinal disease. Progressive body weight loss of 0.05% of peak body weight per day predicted which marmosets would develop disease prior to the terminal stage. Bone tissue-specific tests, such as quantitative analysis of radiographs and serum parathyroid hormone levels, were effective for distinguishing between marmosets with bone disease and those without. These results provide an avenue for making informed decisions regarding the removal of affected marmosets from studies in a timely manner, preserving the integrity of research results.

Contributions of the S100A9 C-terminal tail to high-affinity Mn(II) chelation by the host-defense protein human calprotectin

Human calprotectin (CP) is an antimicrobial protein that coordinates Mn(II) with high affinity in a Ca(II)-dependent manner at an unusual histidine-rich site (site 2) formed at the S100A8/S100A9 dimer interface. We present a 16-member CP mutant family where mutations in the S100A9 C-terminal tail (residues 96-114) are employed to evaluate the contributions of this region, which houses three histidines and four acidic residues, to Mn(II) coordination at site 2. The results from analytical size-exclusion chromatography, Mn(II) competition titrations, and electron paramagnetic resonance spectroscopy establish that the C-terminal tail is essential for high-affinity Mn(II) coordination by CP in solution. The studies indicate that His103 and His105 (HXH motif) of the tail complete the Mn(II) coordination sphere in solution, affording an unprecedented biological His6 site. These solution studies are in agreement with a Mn(II)-CP crystal structure reported recently (Damo, S. M.; et al. Proc. Natl. Acad. Sci. U.S.A. 2013, 110, 3841). Remarkably high-affinity Mn(II) binding is retained when either H103 or H105 are mutated to Ala, when the HXH motif is shifted from positions 103-105 to 104-106, and when the human tail is substituted by the C-terminal tail of murine S100A9. Nevertheless, antibacterial activity assays employing human CP mutants reveal that the native disposition of His residues is important for conferring growth inhibition against Escherichia coli and Staphylococcus aureus. Within the S100 family, the S100A8/S100A9 heterooligomer is essential for providing high-affinity Mn(II) binding; the S100A7, S100A9(C3S), S100A12, and S100B homodimers do not exhibit such Mn(II)-binding capacity.

Diagnostics and prognostics of inflammatory bowel disease with fecal neutrophil-derived biomarkers calprotectin and lactoferrin

Crohn's disease (CD), ulcerative colitis (UC), and colitis unclassified, collectively defined as inflammatory bowel disease (IBD), are the consequence of chronic inflammatory reactions in the gastrointestinal tissue. Endoscopy with biopsies is the mainstay in the diagnosis of this inflammation and is also important in the assessment of disease activity and monitoring of treatment. Furthermore, mucosal healing is increasingly becoming a therapeutic target for treatment of IBD and the golden standard of assessing it is endoscopy. However, due to the costs, invasiveness, and to limited endoscopic capacity, the need is strong for reliable surrogate markers of intestinal inflammation. Bowel contents, being in close contact with intestinal mucosa, can take up molecules that are measurable from stool samples and thus can serve as markers of inflammation. The fecal neutrophil-derived biomarkers, especially calprotectin and lactoferrin, have several features of an ideal test for detecting intestinal inflammation: they are noninvasive, simple, and low in cost. The utility of these biomarkers in distinguishing IBD from noninflammatory conditions such as irritable bowel syndrome is well documented. They correlate closely with endoscopic activity both in CD and UC. They allow serial monitoring of disease activity and of treatment success, and can even serve in predicting clinical relapse in unsymptomatic patients or sustained remission after induction with TNF-α-blocking agents. In this review an overview will be given to the role of fecal neutrophil-derived biomarkers calprotectin and lactoferrin in diagnostics and prognostics of IBD.

Biomarkers in management of inflammatory bowel disease

In recent years the use of faecal and serologic biomarkers has been evaluated in the diagnosis and management of inflammatory bowel disease (IBD). Faecal calprotectin (FC) has been proposed as a surrogate marker for intestinal inflammation; elevated concentrations in IBD patients have been confirmed in numerous studies. Already available rapid calprotectin tests help to differentiate between IBD and irritable bowel syndrome. Faecal calprotectin greatly correlates with endoscopic activity scales and reflects the mucosal healing; thus in patients in clinical remission high levels of it correlate with increased risk of disease relapse in the following 12 months. Adapting the calprotectin assay as a screening test before colonoscopy enables a significant reduction in endoscopic procedures. ANCA/ASCA antibodies have been used in IBD diagnosis and to distinguish CD from ulcerative colitis (UC). Lactoferrin and S100A12 protein were also used to assess the disease activity. This review aims to present the actual potential of biomarker assays for faster diagnosis of IBD and their ability to monitor the disease course, predict exacerbations and improve the way IBD is managed.

S100A expression and interleukin-10 polymorphisms are associated with ulcerative colitis and diarrhea predominant irritable bowel syndrome

BACKGROUND

Both ulcerative colitis (UC) and diarrhea-predominant irritable bowel syndrome (IBS-D) are associated with alterations in enteric serotonin (5-HT) signaling.

AIMS

The purpose of this study was to compare the rectal and sigmoid colonic mucosal expression of S100A proteins and functional polymorphisms of the 5-HT transporter (5HTT) and interleukin-10 genes in patients with IBS-D or UC with healthy controls.

METHODS

mRNA expression of S100 proteins was measured in sigmoid and rectal biopsies and in rectal epithelium isolated by laser-captured microdissection. Leucocyte DNA was analyzed by PCR-based reaction fragment length polymorphisms and direct sequencing. Clinical symptoms were assessed by the self-rating depression scale and by the gastrointestinal symptom rating scale.

RESULTS

Fifty patients with IBS-D, 56 with UC and 50 healthy controls were studied. Colonic mucosal expression of S100A8 and S100A9 in UC was significantly higher than in IBS or controls and correlated with the UC disease activity index (r = 0.65, p < 0.001). S100A10 expression in the rectal epithelium of the IBS patients was significantly higher (0.643 vs. 0.402, p = 0.01) than in controls and correlated with the SDS scores (r = 0.41, p = 0.002). The frequency of IL10-819 CC genotype was significantly higher in IBS-D (10.7 vs. 0 %, p = 0.047) and UC (16 vs. 0 %, p = 0.007) than that in controls.

CONCLUSION

Overexpression of S100A10 in the rectum may play a role in IBS as it is involved in modulating 5-HT1B receptors. The IL10-819 CC is a candidate genotype for both IBS and UC in Japanese.

Faecal calprotectin concentrations in gastrointestinal diseases

OBJECTIVE

To quantify faecal calprotectin concentrations in a variety of gastrointestinal disorders in order to determine its diagnostic value.

METHODS

Patients with gastrointestinal symptoms undergoing upper or lower endoscopy and healthy control subjects provided stool samples. Calprotectin was quantified by enzyme-linked immunosorbent assay.

RESULTS

The study recruited 210 patients with definitively diagnosed gastrointestinal diseases and 50 control subjects. Calprotectin concentrations were significantly higher in patients with ulcerative colitis or Crohn's disease compared with controls, or patients with colorectal polyps or irritable bowel syndrome. The faecal calprotectin concentration significantly differentiated between inflammatory bowel diseases (IBD) and non-IBD (area under ROC curve 0.949). Calprotectin concentrations were significantly higher in patients with oesophageal polyps or gastric neoplasms than in those with chronic gastritis, stomach ulcers, duodenal ulcers or acute pancreatitis.

CONCLUSION

Calprotectin may be a useful noninvasive marker for the diagnosis of IBD.

Fecal calprotectin more accurately reflects endoscopic activity of ulcerative colitis than the Lichtiger Index, C-reactive protein, platelets, hemoglobin, and blood leukocytes

BACKGROUND

The correlation between noninvasive markers with endoscopic activity according to the modified Baron Index in patients with ulcerative colitis (UC) is unknown. We aimed to evaluate the correlation between endoscopic activity and fecal calprotectin (FC), C-reactive protein (CRP), hemoglobin, platelets, blood leukocytes, and the Lichtiger Index (clinical score).

METHODS

UC patients undergoing complete colonoscopy were prospectively enrolled and scored clinically and endoscopically. Samples from feces and blood were analyzed in UC patients and controls.

RESULTS

We enrolled 228 UC patients and 52 healthy controls. Endoscopic disease activity correlated best with FC (Spearman's rank correlation coefficient r = 0.821), followed by the Lichtiger Index (r = 0.682), CRP (r = 0.556), platelets (r = 0.488), blood leukocytes (r = 0.401), and hemoglobin (r = -0.388). FC was the only marker that could discriminate between different grades of endoscopic activity (grade 0, 16 [10-30] μg/g; grade 1, 35 [25-48] μg/g; grade 2, 102 [44-159] μg/g; grade 3, 235 [176-319] μg/g; grade 4, 611 [406-868] μg/g; P < 0.001 for discriminating the different grades). FC with a cutoff of 57 μg/g had a sensitivity of 91% and a specificity of 90% to detect endoscopically active disease (modified Baron Index ≥ 2).

CONCLUSIONS

FC correlated better with endoscopic disease activity than clinical activity, CRP, platelets, hemoglobin, and blood leukocytes. The strong correlation with endoscopic disease activity suggests that FC represents a useful biomarker for noninvasive monitoring of disease activity in UC patients.

High-affinity manganese coordination by human calprotectin is calcium-dependent and requires the histidine-rich site formed at the dimer interface

Calprotectin (CP) is a transition metal-chelating antimicrobial protein of the calcium-binding S100 family that is produced and released by neutrophils. It inhibits the growth of various pathogenic microorganisms by sequestering the transition metal ions manganese and zinc. In this work, we investigate the manganese-binding properties of CP. We demonstrate that the unusual His(4) motif (site 2) formed at the S100A8/S100A9 dimer interface is the site of high-affinity Mn(II) coordination. We identify a low-temperature Mn(II) spectroscopic signal for this site consistent with an octahedral Mn(II) coordination sphere with simulated zero-field splitting parameters D = 270 MHz and E/D = 0.30 (E = 81 MHz). This analysis, combined with studies of mutant proteins, suggests that four histidine residues (H17 and H27 of S100A8; H91 and H95 of S100A9) coordinate Mn(II) in addition to two as-yet unidentified ligands. The His(3)Asp motif (site 1), which is also formed at the S100A8/S100A9 dimer interface, does not provide a high-affinity Mn(II) binding site. Calcium binding to the EF-hand domains of CP increases the Mn(II) affinity of the His(4) site from the low-micromolar to the mid-nanomolar range. Metal-ion selectivity studies demonstrate that CP prefers to coordinate Zn(II) over Mn(II). Nevertheless, the specificity of Mn(II) for the His(4) site provides CP with the propensity to form mixed Zn:Mn:CP complexes where one Zn(II) ion occupies site 1 and one Mn(II) ion occupies site 2. These studies support the notion that CP responds to physiological calcium ion gradients to become a high-affinity transition metal ion chelator in the extracellular space where it inhibits microbial growth.

Utility of faecal calprotectin analysis in adult inflammatory bowel disease

The inflammatory bowel diseases (IBD), Crohn’s disease and ulcerative colitis, are chronic relapsing, remitting disorders. Diagnosis, along with assessment of disease activity and prognosis present challenges to managing clinicians. Faecal biomarkers, such as faecal calprotectin, are a non-invasive method which can be used to aid these decisions. Calprotectin is a calcium and zinc binding protein found in the cytosol of human neutrophils and macrophages. It is released extracellularly in times of cell stress or damage and can be detected within faeces and thus can be used as a sensitive marker of intestinal inflammation. Faecal calprotectin has been shown to be useful in the diagnosis of IBD, correlates with mucosal disease activity and can help to predict response to treatment or relapse. With growing evidence supporting its use, over the last decade this faecal biomarker has significantly changed the way IBD is managed.

Gram-positive anaerobic cocci--commensals and opportunistic pathogens

Among the Gram-positive anaerobic bacteria associated with clinical infections, the Gram-positive anaerobic cocci (GPAC) are the most prominent and account for approximately 25-30% of all isolated anaerobic bacteria from clinical specimens. Still, routine culture and identification of these slowly growing anaerobes to the species level has been limited in the diagnostic laboratory, mainly due to the requirement of prolonged incubation times and time-consuming phenotypic identification. In addition, GPAC are mostly isolated from polymicrobial infections with known pathogens and therefore their relevance has often been overlooked. However, through improvements in diagnostic and in particular molecular techniques, the isolation and identification of individual genera and species of GPAC associated with specific infections have been enhanced. Furthermore, the taxonomy of GPAC has undergone considerable changes over the years, mainly due to the development of molecular identification methods. Existing species have been renamed and novel species have been added, resulting in changes of the nomenclature. As the abundance and significance of GPAC in clinical infections grow, knowledge of virulence factors and antibiotic resistance patterns of different species becomes more important. The present review describes recent advances of GPAC and what is known of the biology and pathogenic effects of Anaerococcus, Finegoldia, Parvimonas, Peptoniphilus and Peptostreptococcus, the most important GPAC genera isolated from human infections.

Between-assay variability of faecal calprotectin enzyme-linked immunosorbent assay kits

BACKGROUND

Faecal calprotectin (f-Cp), a marker of intestinal inflammation, can be used to distinguish between functional and organic bowel disease. F-Cp, following extraction, is commonly quantified using enzyme-linked immunosorbent assays (ELISAs) but there are no data comparing the different f-Cp assays or sample extraction devices. We, therefore, evaluated and compared the performance of the Immunodiagnostik, Bühlmann and Eurospital f-Cp ELISA assays as well as the Roche, Immunodiagnostik and ScheBo Biotech commercial faecal extraction devices. We also briefly report results from a pilot f-Cp external quality assurance (EQA) scheme.

METHODS

Imprecision, linearity, recovery, drift and limit of quantitation of the f-Cp assays were evaluated and between-assay variability assessed. The three commercial sample extraction devices were compared with the manual weighing method. Four faecal samples were distributed as part of a pilot EQA scheme to 15 laboratories using quantitative ELISA f-Cp assays.

RESULTS

The three f-Cp assays demonstrated adequate intra-/interbatch imprecision, linearity and recovery. The cross-comparison study and EQA data demonstrated that, for the same sample, the Bühlmann assay reports up to 3.8 times higher f-Cp concentrations than the Immunodiagnostik and Eurospital assays. On average, the commercial extraction devices led to a 7.8-28.1% under-recovery of f-Cp in comparison to the manual weighing method.

CONCLUSIONS

Laboratories should be aware of the lack of the assay standardization, as demonstrated by the between-assay variability. A comparison between f-Cp concentrations reported by these assays and clinical markers of disease severity is required in order to determine their diagnostic accuracy. The EQA scheme represents the first available programme for f-Cp.

Calcium ion gradients modulate the zinc affinity and antibacterial activity of human calprotectin

Calprotectin (CP) is an antimicrobial protein produced and released by neutrophils that inhibits the growth of pathogenic microorganisms by sequestering essential metal nutrients in the extracellular space. In this work, spectroscopic and thermodynamic metal-binding studies are presented to delineate the zinc-binding properties of CP. Unique optical absorption and EPR spectroscopic signatures for the interfacial His(3)Asp and His(4) sites of human calprotectin are identified by using Co(II) as a spectroscopic probe. Zinc competition titrations employing chromophoric Zn(II) indicators provide a 2:1 Zn(II):CP stoichiometry, confirm that the His(3)Asp and His(4) sites of CP coordinate Zn(II), and reveal that the Zn(II) affinity of both sites is calcium-dependent. The calcium-insensitive Zn(II) competitor ZP4 affords dissociation constants of K(d1) = 133 ± 58 pM and K(d2) = 185 ± 219 nM for CP in the absence of Ca(II). These values decrease to K(d1) ≤ 10 pM and K(d2) ≤ 240 pM in the presence of excess Ca(II). The K(d1) and K(d2) values are assigned to the His(3)Asp and His(4) sites, respectively. In vitro antibacterial activity assays indicate that the metal-binding sites and Ca(II)-replete conditions are required for CP to inhibit the growth of both Gram-negative and -positive bacteria. Taken together, these data provide a working model whereby calprotectin responds to physiological Ca(II) gradients to become a potent Zn(II) chelator in the extracellular space.