Functional and clinical aspects of the myelomonocyte protein calprotectin

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.

Limitations of fecal calprotectin at diagnosis in untreated pediatric Crohn's disease

BACKGROUND

Fecal Calprotectin (FC) is a validated screening test for intestinal inflammation in Crohn's disease (CD). The objective of the study was to prospectively evaluate the limitations of FC for identifying CD in newly diagnosed untreated pediatric patients and to assess the association of FC levels with disease location and serum inflammatory markers.

METHODS

Consecutive children with new onset untreated CD participating in the ongoing ESPGHAN GROWTH CD study were evaluated at diagnosis for disease activity, extent, C-reactive protein (CRP), and FC.

RESULTS

In all, 60 children met the inclusion criteria (mean age 12.6 ± 4.6 years,), 25 (42%) with mild disease, 17 (28%) moderate disease, and 18 (30%) severe disease. Twenty-seven (45%) had small bowel disease only. Median FC levels did not differ between children with small bowel only (2198 μg/g interquartile range [IQR] 696-2400) and those with colonic involvement (with or without small bowel disease; 2400 μg/g (IQR 475-2400) (P = 0.76). FC was elevated in 95% of patients, in comparison to CRP (86%) and erythrocyte sedimentation rate (ESR) (83%). Three children (5%) who had normal calprotectin levels also had low or normal CRP and/or ESR. There was no correlation between calprotectin levels and either the pediatric CD activity index (r = -0.11; P = 0.94) or physicians global assessment.

CONCLUSIONS

FC levels in active disease confined to the small bowel were elevated in the vast majority of children and site of disease was not a confounding factor in this setting. Patients with low FC had a trend toward low levels of inflammatory markers as well. We did not find a significant correlation between FC and clinical indices of activity.

Zinc sequestration by the neutrophil protein calprotectin enhances Salmonella growth in the inflamed gut

Neutrophils are innate immune cells that counter pathogens by many mechanisms, including release of antimicrobial proteins such as calprotectin to inhibit bacterial growth. Calprotectin sequesters essential micronutrient metals such as zinc, thereby limiting their availability to microbes, a process termed nutritional immunity. We find that while calprotectin is induced by neutrophils during infection with the gut pathogen Salmonella Typhimurium, calprotectin-mediated metal sequestration does not inhibit S. Typhimurium proliferation. Remarkably, S. Typhimurium overcomes calprotectin-mediated zinc chelation by expressing a high affinity zinc transporter (ZnuABC). A S. Typhimurium znuA mutant impaired for growth in the inflamed gut was rescued in the absence of calprotectin. ZnuABC was also required to promote the growth of S. Typhimurium over that of competing commensal bacteria. Thus, our findings indicate that Salmonella thrives in the inflamed gut by overcoming the zinc sequestration of calprotectin and highlight the importance of zinc acquisition in bacterial intestinal colonization.

Monitoring inflammatory bowel disease activity: clinical activity is judged to be more relevant than endoscopic severity or biomarkers

BACKGROUND

There is increasing evidence for the clinical relevance of mucosal healing (MH) as therapeutic treatment goal in inflammatory bowel disease (IBD). We aimed to investigate by which method gastroenterologists monitor IBD activity in daily practice.

METHODS

A questionnaire was sent to all board-certified gastroenterologists in Switzerland to specifically address their strategy to monitor IBD between May 2009 and April 2010.

RESULTS

The response rate was 57% (153/270). Fifty-two percent of gastroenterologists worked in private practice and 48% worked in hospitals. Seventy-eight percent judged clinical activity to be the most relevant criterion for monitoring IBD activity, 15% chose endoscopic severity, and 7% chose biomarkers. Seventy percent of gastroenterologists based their therapeutic decisions on clinical activity, 24% on endoscopic severity, and 6% on biomarkers. The following biomarkers were used for IBD activity monitoring: CRP, 94%; differential blood count, 78%; fecal calprotectin (FC), 74%; iron status, 63%; blood sedimentation rate, 3%; protein electrophoresis, 0.7%; fecal neutrophils, 0.7%; and vitamin B12, 0.7%. Gastroenterologists in hospitals and those with ≤ 10 years of professional experience used FC more frequently compared with colleagues in private practice (P=0.035) and those with > 10 years of experience (P<0.001).

CONCLUSIONS

Clinical activity is judged to be more relevant for monitoring IBD activity and guiding therapeutic decisions than endoscopic severity and biomarkers. As such, the accumulating scientific evidence on the clinical impact of mucosal healing does not yet seem to influence the management of IBD in daily gastroenterologic practice.

The soluble biomarker calprotectin (an S100 protein) is associated to ultrasonographic synovitis scores and is sensitive to change in patients with rheumatoid arthritis treated with adalimumab

INTRODUCTION

Calprotectin (MRP8/MRP14, S100A8/A9) is associated with disease activity in patients with rheumatoid arthritis (RA). Ultrasonography (US) is a reliable method for evaluation of synovitis (B-mode (BM) and power Doppler (PD)). The present objectives were to explore in RA patients the associations between calprotectin and a comprehensive US examination, as well as the responsiveness of calprotectin compared to other inflammatory markers during anti-TNF treatment.

METHODS

A total of 20 RA patients starting treatment with adalimumab were examined longitudinally by US (BM and PD (semi-quantitative scores 0 to 3) of 78 joints, 36 tendons/tendon groups and 2 bursae) and clinically at baseline and after 1, 3, 6 and 12 months. Associations between the US sum scores and the inflammatory markers calprotectin, serum amyloid A (SAA), CRP and ESR were explored by correlation and linear regression analyses, and the response to treatment was assessed by Standardized Response Mean (SRM).

RESULTS

The inflammatory markers, clinical examinations and US sum scores improved during treatment (P < 0.001). Of the inflammatory markers, calprotectin had the highest correlation coefficients with the total BM and PD sum scores (median (range) 0.59 (0.37 to 0.76) for BM and 0.56 (0.38 to 0.72) for PD). Even higher correlations were found between calprotectin and sum US scores of reduced number of joint counts. Calprotectin made a considerable contribution to total US sum scores in the linear regression analyses (P = 0.001 to 0.031) and among the inflammatory markers, calprotectin had the highest SRM (0.84 at one month).

CONCLUSIONS

Calprotectin was associated with the sum scores from a comprehensive US assessment and was responsive to change during anti-TNF treatment. Thus, examination of this leukocyte protein could be of additional value in the assessment of RA patients on biologic treatment.

Fecal eosinophil cationic protein as a marker of active disease and treatment outcome in collagenous colitis: a pilot study

BACKGROUND AND AIMS

Fecal calprotectin (FC) is used as a marker for intestinal inflammation in inflammatory bowel disease (IBD) but there is no reliable marker for collagenous colitis (CC). We have previously demonstrated that the mucosal inflammation in CC is characterized by eosinophil activation, which is restored during budesonide treatment, but there is no enhanced neutrophil activity. The aim of this study was to evaluate the use of fecal eosinophil cationic protein (F-ECP) and eosinophil protein X (F-EPX) compared with the neutrophil-derived myeloperoxidase (F-MPO) and FC in patients treated for active CC.

METHODS

Patients with active CC (n = 12) were studied before and after 3, 7, 28 and 56 days of budesonide treatment. Clinical symptoms and stool frequency were recorded, fecal samples were collected, and F-ECP, F-EPX, F-MPO and FC were measured at each occasion.

RESULTS

All but one patient achieved remission. On inclusion 92%, 67%, 67% and 75% of the patients had elevated F-ECP, F-EPX, F-MPO and FC levels, respectively. All markers decreased during the treatment, particularly F-ECP and F-EPX, which decreased after only 3 days. At the end of the study 100%, 92%, 83% and 75% of the patients had normal F-ECP, F-EPX, F-MPO and FC values, respectively.

CONCLUSION

F-ECP demonstrated the best discriminating capacity in detecting active CC. A normalized F-ECP and F-EPX may further be studied as a marker for successful treatment. During budesonide treatment there is a rapid fall in F-ECP and F-EPX, accompanied by clinical improvement, indicating an essential role for the eosinophil participating in the pathophysiology of CC.

A novel zinc binding system, ZevAB, is critical for survival of nontypeable Haemophilus influenzae in a murine lung infection model

Nontypeable Haemophilus influenzae (NTHI) is a Gram-negative bacterial pathogen that causes upper and lower respiratory infections. Factors required for pulmonary infection by NTHI are not well understood. Previously, using high-throughput insertion tracking by deep sequencing (HITS), putative lung colonization factors were identified. Also, previous research indicates that secreted disulfide-dependent factors are important for virulence of H. influenzae. In the present study, HITS data were compared with an informatics-based list of putative substrates of the periplasmic oxidoreductase DsbA to find and characterize secreted virulence factors. This analysis resulted in identification of the "zinc binding essential for virulence" (zev) locus consisting of zevA (HI1249) and zevB (HI1248). NTHI mutants of zevA and zevB grew normally in rich medium but were defective for colonization in a mouse lung model. Mutants also exhibited severe growth defects in medium containing EDTA and were rescued by supplementation with zinc. Additionally, purified recombinant ZevA was found to bind to zinc with high affinity. Together, these data demonstrate that zevAB is a novel virulence factor important for zinc utilization of H. influenzae under conditions where zinc is limiting. Furthermore, evidence presented here suggests that zinc limitation is likely an important mechanism for host defense against pathogens during lung infection.

Faecal calprotectin concentrations in apparently healthy children aged 0-12 years in urban Kampala, Uganda: a community-based survey

Background

Calprotectin is a calcium and zinc binding protein, abundant in neutrophils and is extremely stable in faeces. Faecal calprotectin is used as a non-specific marker for gastrointestinal inflammation. It has a good diagnostic precision to distinguish between irritable bowel syndrome and inflammatory bowel disease. Studies have established normal concentrations in healthy children; all these studies have been performed in high-income countries. The objective of this study was to determine the concentration of faecal calprotectin in apparently healthy children aged 0-12 years in urban Kampala, Uganda.

Method

We tested 302 apparently healthy children aged, age 0-12 years (162 female, 140 male) in urban Kampala, Uganda. The children were recruited consecutively by door-to-door visits. Faecal calprotectin was analyzed using a quantitative enzyme-linked immunosorbent assay. Faeces were also tested for Helicobacter pylori (H. pylori) antigen, for growth of enteropathogens and microscopy was performed to assess protozoa and helminths. A short standardized interview with socio-demographic information and medical history was obtained to assess health status of the children.

Results

In the different age groups the median faecal calprotectin concentrations were 249 mg/kg in 0 < 1 year (n = 54), 75 mg/kg in 1 < 4 years (n = 89) and 28 mg/kg in 4 < 12 years (n = 159). There was no significant difference in faecal calprotectin concentrations and education of female caretaker, wealth index, gender, habits of using mosquito nets, being colonized with H. pylori or having other pathogens in the stool.

Conclusion

Concentrations of faecal calprotectin among healthy children, living in urban Ugandan, a low-income country, are comparable to those in healthy children living in high-income countries. In children older than 4 years, the faecal calprotectin concentration is low. In healthy infants faecal calprotectin is high. The suggested cut-off concentrations in the literature can be used in apparently healthy Ugandan children. This finding also shows that healthy children living under poor circumstances do not have a constant inflammation in the gut. We see an opportunity to use this relatively inexpensive test for further understanding and investigations of gut inflammation in children living in low-income countries.

Fecal calprotectin concentration in celiac disease

GOALS

We aimed to determine fecal calprotectin (FC) concentration and its relation with histopathologic findings of children with celiac disease (CD) and to observe the probable alterations under gluten-free diet (GFD).

BACKGROUND

As FC is regarded as a marker of inflammation in the gastrointestinal tract, we hypothesized that it might be increased in untreated CD.

STUDY

The study included 29 newly diagnosed patients with CD (mean age: 6.6+/-0.6 y) and sex and age-matched 10 healthy children. All of the children with CD admitted to the hospital were classical form who has chronic diarrhea and failure to thrive. The degree of mucosal damage was graded according to the modified Marsh criteria. FC concentration was determined by enzyme-linked immunosorbent assay method on admission and after 1 year of GFD.

RESULTS

Mean FC concentration of children with CD on admission and of healthy children were 13.40+/-8.5 and 4.3+/-3.3 mg/L, respectively (P=0.004). FC concentration under GFD was 4.6+/-2.7 mg/L and there was a significant statistical difference between untreated patients and those under GFD for 1 year (P=0.001). There was no statistical difference between FC concentration of those under GFD and healthy children (P=0.8). Mean FC concentrations of children with total-villous atrophy and partial-villous atrophy were significantly different (13.8+/-9.3 mg/L vs. 3.7+/-1.8 mg/L, P=0.005).

CONCLUSIONS

It was found that FC concentration is increased in childhood CD, related to the severity of histopathologic findings and responsive to GFD. The pathogenetic mechanism by which FC is increased in CD should be investigated in further studies.

Calprotectin in human cord blood: relation to perinatal parameters and restricted fetal growth

OBJECTIVE

To determine cord blood levels of calprotectin, a protein that is increased in inflammatory states and released by activated neutrophils has apoptosis-inducing activity.

MATERIALS AND METHODS

Cord-blood calprotectin concentrations were determined in intrauterine-growth-restricted (IUGR, usually associated with increased neutrophil activation and apoptosis, n=50) and appropriate-for-gestational-age (AGA, n=110) single full-term pregnancies, and were correlated with perinatal demographic parameters.

RESULTS

No significant differences exists between the IUGR and AGA groups, implying that calprotectin at birth does not reflect increased neutrophil activation and apoptosis expected in IUGR. However, in IUGRs, calprotectin concentrations increased with every gestational week [b=45.3, 95% confidence interval (CI): 13.5-77.1, P=0.006], suggesting concomitant up-regulation of neutrophil activation and apoptosis. A combined group showed significantly decreased calprotectin concentrations in cesarean sections [b=-74.5, 95% CI: -115.2-(-33.9), P<0.001], pointing to excessive inflammatory response in vaginal deliveries. Finally, birth weight, customized centile, gender, maternal age and parity do not impact on cord blood calprotectin concentrations.

CONCLUSIONS

Cord blood calprotectin concentrations at term are independent of intrauterine growth, gender, parity and maternal age and probably do not reflect the increased neutrophil activation and excessive apoptosis expected in IUGR.

Evaluation of faecal calprotectin as a valuable non-invasive marker in distinguishing gut pathogens in young children with acute gastroenteritis

AIM

The aim of the study is to evaluate faecal calprotectin (f-CP) in children ≤3 years of age with acute gastroenteritis (AG) as an early predictor of bacterial inflammation.

METHODS

We prospectively analysed f-CP levels and diagnostic workup in 107 consecutive children (66 AG, 41 controls).

RESULTS

Children with bacterial AG (BAG) was found to have higher diarrheal frequency (p < 0.01), fever (p < 0.01), erythrocyte sedimentation rate (p < 0.001), white blood count (p < 0.01) and C-reactive protein (CRP) (p < 0.001) compared with viral AG (VAG). Vomiting was frequent in VAG (p < 0.001). f-CP negatively correlated with age in controls (r = -0.5998). BAG demonstrated significantly higher f-CP levels [median, 219 μg/g, interquartile range (IQR): 119-350.2] compared with VAG (49.3 μg/g, IQR: 8.8-131.1) as well as controls (26.5 μg/g, IQR: 14.9-55.1) (p < 0.001). VAG and control f-CP levels were similar. f-CP was the best-rated marker of BAG with a diagnostic accuracy of 92%. Receiver-operator characteristic analysis revealed an area under curve of 0.95 for identifying BAG; sensitivity and specificity of f-CP were 93% and 88%, respectively, at an adjusted cut-off point of 103.9 μg/g faeces. Combined f-CP and CRP yield improved diagnostic accuracy of 94% for BAG.

CONCLUSION

f-CP facilitates early discrimination between bacterial and viral causes of AG in young children. Combining f-CP with CRP increases the diagnostic power of diagnosing BAG.

Can chronic gastritis cause an increase in fecal calprotectin concentrations?

AIM: To evaluate fecal calprotectin concentrations (FCCs) in subjects with chronic gastritis and the correlation between FCCs and gastritis activity score.

METHODS: FCCs were measured in 61 patients with histological diagnosis of gastritis and in 74 healthy volunteers. Histological grading of gastritis was performed according to the updated Sydney gastritis classification. Patients were subdivided into 2 groups according to the presence/absence of an active gastritis. Patients with chronic active gastritis were divided into 3 subgroups on the basis of the activity score (mild, moderate, marked). FFCs in relation to Helicobacter pylori (H. pylori) infection and proton pump inhibitor (PPI) use were also evaluated.

RESULTS: FCCs in patients with chronic active gastritis were not significantly different to FCCs either in subjects with non active gastritis or in healthy controls. Among patients with chronic active gastritis (even marked), FCCs did not significantly differ according to activity score. No significant differences in FCCs were found when considering H. pylori, as well as when considering PPI chronic use.

CONCLUSION: FCCs were not significantly increased in subjects with chronic gastritis, even in those patients with a marked neutrophil infiltration.

Fecal calprotectin excretion in preterm infants during the neonatal period

BACKGROUND

Fecal calprotectin has been proposed as a non-invasive marker of intestinal inflammation in inflammatory bowel disease in adults and children. Fecal calprotectin levels have been reported to be much higher in both healthy full-term and preterm infants than in children and adults.

OBJECTIVE

To determine the time course of fecal calprotectin (f-calprotectin) excretion in preterm infants from birth until hospital discharge and to identify factors influencing f-calprotectin levels in the first weeks of life, including bacterial establishment in the gut.

METHODOLOGY

F-calprotectin was determined using an ELISA assay in 147 samples obtained prospectively from 47 preterm infants (gestational age, and birth-weight interquartiles 27-29 weeks, and 880-1320 g, respectively) at birth, and at 2-week intervals until hospital discharge.

PRINCIPAL FINDINGS

Although median f-calprotectin excretion was 138 microg/g, a wide range of inter- and intra-individual variation in f-calprotectin values (from day 3 to day 78) was observed (86% and 67%, respectively). In multivariate regression analysis, f-calprotectin correlated negatively with ante and per natal antibiotic treatment (p = 0.001), and correlated positively with the volume of enteral feeding (mL/kg/d) (p = 0.009), the need to interrupt enteral feeding (p = 0.001), and prominent gastrointestinal colonization by Clostridium sp (p = 0.019) and Staphylococcus sp (p = 0.047).

CONCLUSION

During the first weeks of life, the high f-calprotectin values observed in preterm infants could be linked to the gut bacterial establishment.

Diagnostic value of faecal calprotectin in unselected outpatients referred for colonoscopy: A multicenter prospective study

OBJECTIVES

To evaluate the role of faecal calprotectin in consecutive outpatients referred for colonoscopy.

METHODS

Outpatients undergoing colonoscopy at five participating institutions were eligible. Demographic and clinical data were collected. Faecal samples were tested at a single laboratory by means of a commercially available kit.

RESULTS

We consecutively enrolled 870 patients. Mean levels of calprotectin were significantly higher in patients with neoplastic and inflammatory disorders when compared with subjects with a normal colonoscopy or trivial endoscopic findings. Elevated calprotectin levels (>50mg/dl) were detected in 85% of patients with colorectal cancer, and 81% of those with inflammatory conditions but also in 37% of patients with normal or trivial endoscopic findings. In patients referred for chronic diarrhoea, sensitivity and negative predictive value were 100% in detecting either any organic colonic disease. In patients referred for symptoms of "suspected functional origin" sensitivity and negative predictive value for colorectal cancer were also 100%.

CONCLUSIONS

In unselected outpatients referred for colonoscopy, a single measurement of faecal calprotectin is not sufficiently accurate to identify those with significant colorectal disease. However, a normal result can help rule out organic disease among patients with diarrhoea and those with abdominal pain and/or constipation.

S100A8/A9: a mediator of severe asthma pathogenesis and morbidity?

Nearly 12% of children and 6% of adults in Canada have been diagnosed with asthma. Although in most patients symptoms are controlled by inhaled steroids, a subpopulation (approximately 10%) characterized by excessive airway neutrophilia, is refractory to treatment; these patients exhibit severe disease, and account for more than 50% of asthma health care costs. These numbers underscore the need to better understand the biology of severe asthma and identify pro-asthma mediators released by cells, such as neutrophils, that are unresponsive to common steroid therapy. This review focuses on a unique protein complex consisting of S100A8 and S100A9. These subunits belong to the large Ca2+-binding S100 protein family and are some of the most abundant proteins in neutrophils and macrophages. S100A8/A9 is a damage-associated molecular pattern (DAMP) protein complex released in abundance in rheumatoid arthritis, inflammatory bowel disease, and cancer, but there are no definitive studies on its role in inflammation and obstructive airways disease. Two receptors for S100A8/A9, the multiligand receptor for advanced glycation end products (RAGE) and Toll-like receptor 4 (TLR4), are expressed in lung. TLR4 is linked with innate immunity that programs local airway inflammation, and RAGE participates in mediating fibroproliferative remodeling in idiopathic pulmonary fibrosis. S100A8/A9 can induce cell proliferation, or apoptosis, inflammation, collagen synthesis, and cell migration. We hypothesize that this capacity suggests S100A8/A9 could underpin chronic airway inflammation and airway remodeling in asthma by inducing effector responses of resident and infiltrating airway cells. This review highlights some key issues related to this hypothesis and provides a template for future research.

Calprotectin (S100A8/S100A9) and myeloperoxidase: co-regulators of formation of reactive oxygen species

Inflammatory mediators trigger polymorphonuclear neutrophils (PMN) to produce reactive oxygen species (ROS: O₂^-, H₂O₂, ∙OH). Mediated by myeloperoxidase in PMN, HOCl is formed, detectable in a chemiluminescence (CL) assay. We have shown that the abundant cytosolic PMN protein calprotectin (S100A8/A9) similarly elicits CL in response to H₂O₂ in a cell-free system. Myeloperoxidase and calprotectin worked synergistically. Calprotectin-induced CL increased, whereas myeloperoxidase-triggered CL decreased with pH > 7.5. Myeloperoxidase needed NaCl for CL, calprotectin did not. 4-hydroxybenzoic acid, binding ∙OH, almost abrogated calprotectin CL, but moderately increased myeloperoxidase activity. The combination of native calprotectin, or recombinant S100A8/A9 proteins, with NaOCl markedly enhanced CL. NaOCl may be the synergistic link between myeloperoxidase and calprotectin. Surprisingly- and unexplained- at higher concentration of S100A9 the stimulation vanished, suggesting a switch from pro-oxidant to anti-oxidant function. We propose that the ∙OH is predominant in ROS production by calprotectin, a function not described before.

Fecal calprotectin correlates more closely with the Simple Endoscopic Score for Crohn's disease (SES-CD) than CRP, blood leukocytes, and the CDAI

OBJECTIVES

Studies evaluating the correlation between the widely used Simple Endoscopic Score for Crohn's disease (SES-CD) and noninvasive markers are scarce. The aim of this study was to evaluate the correlation between the SES-CD and fecal calprotectin, C-reactive protein (CRP), blood leukocytes, and the Crohn's disease activity index (CDAI).

METHODS

Crohn's disease patients undergoing complete ileocolonoscopy were prospectively enrolled and scored independently according to the SES-CD and the CDAI. SES-CD was defined as follows: inactive 0-3; mild 4-10; moderate 11-19; and high > or =20.

RESULTS

Values in CD patients (n=140 ileocolonoscopies) compared with controls (n=43) are as follows: calprotectin, 334+/-322 vs. 18+/-5 microg/g; CRP, 26+/-29 vs. 3+/-2 mg/l; and blood leukocytes, 9.1+/-3.4 vs. 5.4+/-1.9 g/l (all P<0.001). The SES-CD correlated closest with calprotectin (Spearman's rank correlation coefficient r=0.75), followed by CRP (r=0.53), blood leukocytes (r=0.42), and the CDAI (r=0.38). Calprotectin was the only marker that could discriminate inactive endoscopic disease from mild activity (104+/-138 vs. 231+/-244 microg/g, P<0.001), mild from moderate activity (231+/-244 vs. 395+/-256 microg/g, P=0.008), and moderate from high activity (395+/-256 vs. 718+/-320 microg/g, P<0.001). The overall accuracy for the detection of endoscopically active disease was 87% for calprotectin (cutoff 70 microg/g), 66% for elevated CRP, 54% for blood leukocytosis, and 40% for the CDAI > or =150.

CONCLUSIONS

Fecal calprotectin correlated closest with SES-CD, followed by CRP, blood leukocytes, and the CDAI. Furthermore, fecal calprotectin was the only marker that reliably discriminated inactive from mild, moderate, and highly active disease, which underlines its usefulness for activity monitoring.

Ulcerative colitis: correlation of the Rachmilewitz endoscopic activity index with fecal calprotectin, clinical activity, C-reactive protein, and blood leukocytes

BACKGROUND

The accuracy of noninvasive markers for the detection of endoscopically active ulcerative colitis (UC) according the Rachmilewitz Score is so far unknown. The aim was to evaluate the correlation between endoscopic disease activity and fecal calprotectin, Clinical Activity Index, C-reactive protein (CRP), and blood leukocytes.

METHODS

UC patients undergoing colonoscopy were prospectively enrolled and scored independently according the endoscopic and clinical part of the Rachmilewitz Index. Patients and controls provided fecal and blood samples for measuring calprotectin, CRP, and leukocytes.

RESULTS

Values in UC patients (n = 134) compared to controls (n = 48): calprotectin: 396 ± 351 versus 18.1 ± 5 μg/g, CRP 16 ± 13 versus 3 ± 2 mg/L, blood leukocytes 9.9 ± 3.5 versus 5.4 ± 1.9 g/L (all P < 0.001). Endoscopic disease activity correlated closest with calprotectin (Spearman's rank correlation coefficient r = 0.834), followed by Clinical Activity Index (r = 0.672), CRP (r = 0.503), and leukocytes (r = 0.461). Calprotectin levels were significantly lower in UC patients with inactive disease (endoscopic score 0-3, calprotectin 42 ± 38 μg/g), compared to patients with mild (score 4-6, calprotectin 210 ± 121 μg/g, P < 0.001), moderate (score 7-9, calprotectin 392 ± 246 μg/g, P = 0.002), and severe disease (score 10-12, calprotectin 730 ± 291 μg/g, P < 0.001). The overall accuracy for the detection of endoscopically active disease (score ≥4) was 89% for calprotectin, 73% for Clinical Activity Index, 62% for elevated CRP, and 60% for leukocytosis.

CONCLUSIONS

Fecal calprotectin correlated closest with endoscopic disease activity, followed by Clinical Activity Index, CRP, and blood leukocytes. Furthermore, fecal calprotectin was the only marker that reliably discriminated inactive from mild, moderate, and highly active disease, which emphasizes its usefulness for activity monitoring.

Phagocyte-specific S100A8/A9 protein levels during disease exacerbations and infections in systemic lupus erythematosus

OBJECTIVE

S100A8 and S100A9 are calcium binding proteins of the S100 family highly expressed in neutrophils and monocytes. S100 proteins are novel ligands of TLR4 important in modulating inflammation. High levels of S100A8/A9 found in human inflammatory diseases are a marker of disease activity in rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA). We determined levels of S100A8/A9 in sera of patients with systemic lupus erythematosus (SLE) and analyzed their relation to clinical variables of disease activity.

METHODS

A group of 93 patients with SLE were studied over a period of 3 years, and 143 serum samples were analyzed. S100A8/A9 serum concentrations were determined by a sandwich ELISA. Sera from 10 primary Sjögren's syndrome (pSS) patients and 50 healthy volunteers were used as controls. Correlations to SLEDAI, ANA, anti-dsDNA, WBC, CH50, C4, and CRP were made. In addition, infections were recorded in all SLE patients.

RESULTS

Serum levels of S100A8/A9 were significantly (p = 0.04) higher in SLE patients (1412 +/- 664 ng/ml) versus healthy controls (339 +/- 35 ng/ml) and pSS patients (400 +/- 85 ng/ml). The only significant correlation (r = 0.219; p = 0.015) was found was between S100A8/A9 and SLEDAI. Further, SLE patients with concomitant infections had higher serum levels of S100A8/A9 (39300 +/- 13375 ng/ml) than those without infections (1150 +/- 422 ng/ml).

CONCLUSION

Serum levels of S100A8/A9 are significantly raised in SLE versus pSS patients and healthy controls and can be correlated to a disease activity index. S100A8/A9 is a more relevant marker of infection in SLE patients.

Faecal DNA and calprotectin as biomarkers of acute intestinal toxicity in patients undergoing pelvic radiotherapy

BACKGROUND

Acute intestinal toxicity is a frequent complication that may lead to interruption of treatment in patients undergoing pelvic radiotherapy. Reliable, non-invasive biological markers to evidence their severity are not yet available.

AIM

To test faecal DNA and calprotectin as potential biomarkers of intestinal toxicity caused by pelvic radiotherapy.

METHODS

Patients were categorized according to the location of the cancer as nonrectal (n = 25) and rectal (n = 27). Four stool samples were collected at weeks w0, w3, w5 (end of radiotherapy) and w7. Faecal DNA was determined by quantitative PCR and calprotectin by ELISA. Intestinal toxicity was scored according to the Common Toxicity Criteria.

RESULTS

In the nonrectal group, acute diarrhoea toxicity was present in 80% of patients, faecal DNA increased 10-fold during radiotherapy (1.5 x 10(3) copies/mg dry weight, 9.5 x 10(2)-8.8 x 10(3) at w0, median and interquartile range vs. 1.3 x 10(4), 1.9 x 10(3)-3.9 x 10(4) at w5, P < 0.01), but was not recovered at w7 (3.4 x 10(3), 1.5 x 10(3)-4.1 x 10(4)) and calprotectin doubled during treatment at w3 and w5. No significant changes in faecal markers were found in the rectal group.

CONCLUSION

Faecal excretion of human DNA and calprotectin increased during pelvic radiotherapy treatment, and may be a good objective biomarker of intestinal damage in nonrectal cancer patients.

Fecal calprotectin in differential diagnosis between irritable bowel syndrome and inflammatory bowel disease

AIM: To assess the value of fecal calprotectin as a non-invasive screening biomarker in differential diagnosis of irritable bowel syndrome (IBS) and inflammatory bowl disease (IBD) using ELISA quantitative analysis.

METHODS: A total of 92 fresh fecal samples were collected from the patients, including 23 cases of UC, 4 cases of CD, 55 cases of irritable bowel syndrome (IBS) and 20 healthy volunteers. EK-CAL was used to quantitatively dete rmine the level of fecal calprotection.

RESULTS: The level of fecal calprotection was 77.15 ± 160.9 μg/g in healthy volunteers, 46.08 ± 131.97 μg/g in IBS patients, 851.34 ± 522.19 μg/g in IBD patients, respectively. There was no significant difference between IBS patients and healthy volunteers (P > 0.05) in levels of fecal calprotection, but there was remarkable difference between the patients with IBS and healthy volunteers. The sensitivity and specificity of fecal calprotection in differentiating the IBD from IBS was 86.7%, 96.3%, respectively.

CONCLUSION: Detection of fecal calprotectin is simple, inexpensive, repeatable and non-invasive. It can be used as a biomarker in differentiating irritable bowel syndrome from inflammatory bowel disease.

Effects of flunixin meglumine on recovery of colonic mucosa from ischemia in horses

OBJECTIVE

To examine the effects of flunixin meglumine (FM) on recovery of colonic mucosa from experimentally induced ischemia in horses.

ANIMALS

14 research horses.

PROCEDURES

Ischemia was induced in the colons of anesthetized horses for 2 hours. Afterward, horses received saline (0.9% NaCl) solution (12 mL, IV, q 12 h; n = 7) or FM (1.1 mg/kg, IV, q 12 h; 7) and were allowed to recover for 18 hours after termination of the ischemic event. Postoperative pain scores were recorded every 4 hours throughout the recovery period. At the end of the recovery period, horses were anesthetized, and ischemic and nonischemic segments of colonic mucosa were harvested for histologic evaluation, western blot analysis, and in vitro assessment of transepithelial electric resistance (TER) and transmucosal flux of tritium-labeled (3H-) mannitol. Horses were then euthanatized.

RESULTS

Flunixin meglumine significantly lowered pain scores at the first postoperative recording. There were no significant differences between treatment with saline solution and FM in any of the measurements for TER, 3H-mannitol flux, histomorphometric variables, neutrophil infiltration (detected via calprotectin immunostaining), and expressions of cyclooxygenase-1 and -2. After both treatments, TER declined significantly in nonischemic tissues in vitro, whereas it increased significantly in ischemic-injured tissues.

CONCLUSIONS AND CLINICAL RELEVANCE

Flunixin meglumine did not affect recovery of equine colonic mucosa from ischemic injury, and continued use in horses with colonic ischemia is therefore justified.

Hyperzincemia and hypercalprotectinemia: unsuccessful treatment with tacrolimus

We report on a 5-year-old boy with hyperzincemia and hypercalprotectinemia. Treatment began with Tacrolimus at the age of 4 years and 6 months. Despite an initial correction of clinical and biological symptoms, zincemia and calprotectinemia progressively worsened with secondary reappearance of symptoms.

CONCLUSION

Tacrolimus seems to have a transient effect in the treatment of Hyperzincemia and hyperprolactinemia.

Calprotectin S100A9 calcium-binding loops I and II are essential for keratinocyte resistance to bacterial invasion

Epithelial cells expressing calprotectin, a heterodimer of S100A8 and S100A9 proteins, are more resistant to bacterial invasion. To determine structural motifs that affect resistance to bacterial invasion, mutations were constructed in S100A9 targeting the calcium-binding loops I and II (E36Q, E78Q, E36Q,E78Q) and the C terminus (S100A9(1-99) and S100A9(1-112)), which contains putative antimicrobial zinc-binding and phosphorylation sites. The S100A8 and mutated S100A9 encoding plasmids were transfected into calprotectin-negative KB carcinoma cells. All transfected cells (except KB-sham) expressed 27E10-reactive heterodimers. In bacterial invasion assays with Listeria monocytogenes and Salmonella enterica serovar Typhimurium (Salmonella typhimurium), cell lines expressing S100A8 in complex with S100A9E36Q, S100A9E78Q, S100A9(1-99), or S100A9(1-112) mutants or the S100A9(1-114) (full-length) calprotectin resisted bacterial invasion better than KB-sham. When compared with KB-S100A8/A9(1-114), cells expressing truncated S100A9(1-99) or S100A9(1-112) with S100A8 also showed increased resistance to bacterial invasion. In contrast, glutamic acid residues 36 and 78 in calcium-binding loops I and II promote resistance in epithelial cells, because cells expressing S100A9E36Q,E78Q with S100A8 were unable to resist bacterial invasion. Mutations in S100A9 E36Q, E78Q were predicted to cause loss of the calcium-induced positive face in calprotectin, reducing interactions with microtubules and appearing to be crucial for keratinocyte resistance to bacterial invasion.

Validation and clinical significance of a new calprotectin rapid test for the diagnosis of gastrointestinal diseases

AIMS

Objective of this study was to compare the assay characteristics of a new fecal calprotectin rapid test with an enzyme-linked immunosorbent assay (ELISA). The second aim was to assess the potential of measuring fecal calprotectin as screening method for intestinal inflammation and colorectal malignancies.

PATIENTS AND METHODS

One hundred forty patients with lower gastrointestinal symptoms referred to colonoscopy provided fecal samples (56, control group; 18, diverticulosis; 29, colorectal adenoma; 8, colorectal carcinoma (CRC); 18, active inflammatory bowel disease (IBD); 11, intestinal infections). Feces were analyzed by two assay methods.

RESULTS

Compared to the control group (median 25.8 microg/g), calprotectin levels were significantly increased in adenoma (66.3 microg/g), CRC (164 microg/g), intestinal infections (306 microg/g), and active IBD (797 microg/g). An adequate diagnostic accuracy could be found for active IBD with a sensitivity, specificity, and an area under the curve (AUC) of 100%, 79%, and 0.955 (ELISA) vs. 89%, 80%, and 0.896 (rapid test). Similar results were obtained for CRC (100%, 79%, 0.922 vs. 100%, 80%, 0.948) whereas in adenomas a low sensitivity, specificity, and AUC of 55%, 79%, and 0.686 vs. 52%, 80%, and 0.666 were found for fecal calprotectin.

CONCLUSIONS

Both fecal calprotectin assays are effective in identifying active IBD and CRC but lack analytical sensitivity in separating CRC from adenoma as well as adenoma from the control group. The new calprotectin rapid test is a convenient method for assessing the calprotectin level in an outpatient setting. Henceforth, it provides a precondition for the fecal calprotectin method to challenge fecal occult blood testing in further evaluations.

Fecal markers of inflammation used as surrogate markers for treatment outcome in relapsing inflammatory bowel disease

AIM: To evaluate fecal calprotectin (FC) as a surrogate marker of treatment outcome of relapse of inflammatory bowel disease (IBD) and, to compare FC with fecal myeloperoxidase (MPO) and fecal eosinophil protein X (EPX).

METHODS: Thirty eight patients with IBD, comprising of 27 with ulcerative colitis (UC) and 11 with Crohn’s disease (CD) were investigated before treatment (inclusion), and after 4 and 8 wk of treatment. Treatment outcomes were evaluated by clinical features of disease activity and endoscopy in UC patients, and disease activity in CD patients. In addition, fecal samples were analyzed for FC by enzyme-linked immunosorbent assay (ELISA), and for MPO and EPX with radioimmunoassay (RIA).

RESULTS: At inclusion 37 of 38 (97%) patients had elevated FC levels (> 94.7 μg/g). At the end of the study, 31 of 38 (82%) patients fulfilled predefined criteria of a complete response [UC 21/27 (78%); CD 10/11 (91%)]. Overall, a normalized FC level at the end of the study predicted a complete response in 100% patients, whereas elevated FC level predicted incomplete response in 30%. Normalized MPO or EPX levels predicted a complete response in 100% and 90% of the patients, respectively. However, elevated MPO or EPX levels predicted incomplete response in 23% and 22%, respectively.

CONCLUSION: A normalized FC level has the potential to be used as a surrogate marker for successful treatment outcome in IBD patients. However, patients with persistent elevation of FC levels need further evaluation. FC and MPO provide superior discrimination than EPX in IBD treatment outcome.

Fecal markers of inflammation used as surrogate markers for treatment outcome in relapsing inflammatory bowel disease

AIM

To evaluate fecal calprotectin (FC) as a surrogate marker of treatment outcome of relapse of inflammatory bowel disease (IBD) and, to compare FC with fecal myeloperoxidase (MPO) and fecal eosinophil protein X (EPX).

METHODS

Thirty eight patients with IBD, comprising of 27 with ulcerative colitis (UC) and 11 with Crohn's disease (CD) were investigated before treatment (inclusion), and after 4 and 8 wk of treatment. Treatment outcomes were evaluated by clinical features of disease activity and endoscopy in UC patients, and disease activity in CD patients. In addition, fecal samples were analyzed for FC by enzyme-linked immunosorbent assay (ELISA), and for MPO and EPX with radioimmunoassay (RIA).

RESULTS

At inclusion 37 of 38 (97%) patients had elevated FC levels (> 94.7 microg/g). At the end of the study, 31 of 38 (82%) patients fulfilled predefined criteria of a complete response [UC 21/27 (78%); CD 10/11 (91%)]. Overall, a normalised FC level at the end of the study predicted a complete response in 100% patients, whereas elevated FC level predicted incomplete response in 30%. Normalised MPO or EPX levels predicted a complete response in 100% and 90% of the patients, respectively. However, elevated MPO or EPX levels predicted incomplete response in 23% and 22%, respectively.

CONCLUSION

A normalised FC level has the potential to be used as a surrogate marker for successful treatment outcome in IBD patients. However, patients with persistent elevation of FC levels need further evaluation. FC and MPO provide superior discrimination than EPX in IBD treatment outcome.

Fecal calprotectin concentrations are higher in exclusively breastfed infants compared to those who are mixed-fed

BACKGROUND

Previous studies have shown that giving other foods while breastfeeding increases the risk of mother-to-child transmission of human immunodeficiency virus (HIV) type 1. The mechanism is speculated to be increased inflammation of the gastrointestinal tract.

METHODS

In a prospective longitudinal study, we compared fecal calprotectin, a marker of intestinal inflammatory disease, in healthy U.S. infants 0-6 months of age who were exclusively breastfed compared to those given additional liquids or solids.

RESULTS

In comparison to infants who were mixed-fed, fecal calprotectin was significantly higher in the exclusively breastfed group (p = 0.01) by a mean of 60 mg/kg (SE = 23).

CONCLUSIONS

Introducing complementary food does not increase intestinal inflammation according to this marker. Studies to assess fecal calprotectin levels in breastfeeding and mixed-fed infants born to HIV-infected mothers living in resource-constrained settings, and to evaluate potential protective effects of calprotectin in early infancy, are recommended in the continuing effort to elucidate the mechanisms responsible for increased risk of HIV transmission through mixed-feeding.

Fecal calprotectin is useful in predicting disease relapse in pediatric inflammatory bowel disease

BACKGROUND

Fecal calprotectin (FC) has been proposed as a noninvasive surrogate marker to determine the degree of intestinal inflammation and predicting relapse in patients with inflammatory bowel disease (IBD). The aim was to compare FC levels in IBD and healthy controls, to correlate FC levels with clinical disease activity, and to assess whether FC levels can be used to predict clinical relapse in children with IBD.

METHODS

Enzyme-linked immunosorbent assay (ELISA) determined levels of FC were measured in more than 1 stool samples (n) from 32 IBD patients (n = 97) and from 34 healthy controls (n = 37). Disease activity was assessed by the Harvey-Bradshaw index in Crohn's disease (CD) and by Physician's Global Assessment (PGA) in both CD and ulcerative colitis (UC). Clinical events were recorded up to 9 months following stool collection in CD patients. Wilcoxon rank sum test and Fisher's exact tests were used to compare FC levels in IBD patients and in control. Kaplan-Meyer analysis was used to determine a risk of clinical relapse in relation to FC levels.

RESULTS

The IBD group had higher FC levels (range 17-7500 g/g) compared with control (16-750 g/g, P < 0.0001). FC levels were higher during relapse (CD, 3214 +/- 2186; UC, 2819 +/- 1610) compared to remission (CD, 1373 +/- 1630; UC, 764 +/- 869; P < 0.0001). Among those with clinical relapse, 90% had FC levels more than 400 mug/g in CD. Eighty-nine percent of CD encounters with FC levels less than 400 mug/g remained in clinical remission.

CONCLUSIONS

FC levels differentiate active IBD from controls. Among children with CD and in remission, FC levels may be useful in predicting impending clinical relapse.

Physical activity before and after diagnosis of colorectal cancer: disease risk, clinical outcomes, response pathways and biomarkers

Physical inactivity may be responsible for 13-14% of colon cancer, an attributable risk greater than family history. Epidemiological evidence shows an association between occupational and recreational physical activity and colon cancer, but has not established whether physical activity is protective against low-risk or more advanced adenomas. The evidence is inconclusive as to whether physical activity protects against rectal cancer and is conflicting with respect to whether physical activity has equal effects on male and female risk of colorectal cancer. The effect of exercise 'interventions' on the risk of colorectal cancer is currently not known. Also, although inferences can be made from epidemiological studies, no optimal exercise regimen can be confidently prescribed for protection against colorectal cancer. There is little available evidence for the benefits of physical activity before diagnosis of colorectal cancer for disease-specific survival and prognosis, and the clinical effects of an exercise intervention after diagnosis have not been investigated. There is some evidence that improvements in cardiorespiratory fitness reduce adverse effects from cancer treatment when physical activity is undertaken following diagnosis of colorectal cancer. Markers/mechanisms by which physical activity may protect against colorectal cancer and/or improve disease prognosis include gastrointestinal transit-time, chronic inflammation, immune function, insulin levels, insulin-like growth factors, genetics and obesity. Research evidence is, however, limited as to whether these markers are beneficially affected by physical activity, either before or after diagnosis of colorectal cancer.

Clinical value of fecal calprotectin in determining disease activity of ulcerative colitis

AIM: To investigate possibility and clinical application of fecal calprotectin in determining disease activity of ulcerative colitis (UC).

METHODS: The enzyme-linked immunosorbent assay (ELISA) was used to measure the concentrations of calprotectin in feces obtained from 66 patients with UC and 20 controls. C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), acid glycoprotein (AGP) were also measured and were compared with calprotectin in determining disease activity of UC. The disease activity of UC was also determined by the Sutherland criteria.

RESULTS: The fecal calprotectin concentration in the patients with active UC was significantly higher than that in the inactive UC and in the controls (402.16 ± 48.0 &mgr;g/g vs 35.93 ± 3.39 &mgr;g/g, 11.5 ± 3.42 &mgr;g/g, P < 0.01). The fecal calprotectin concentration in the inactive UC group was significantly higher than that in the control group (P < 0.05). A significant difference was also found in the patients with active UC of mild, moderate and severe degrees. The area under the curve of the receiver operating characteristics (AUC^ROC) was 0.975, 0.740, 0.692 and 0.737 for fecal calprotectin, CRP, ESR and AGP, respectively. There was a strong correlation between the fecal calprotectin concentration and the endoscopic gradings for UC (r = 0.866, P < 0.001).

CONCLUSION: Calprotectin in the patient’s feces can reflect the disease activity of UC and can be used as a rational fecal marker for intestinal inflammation in clinical practice. This kind of marker is relatively precise, simple and noninvasive when compared with other commonly-used markers such as CRP, ESR and AGP.

Discriminating IBD from IBS: comparison of the test performance of fecal markers, blood leukocytes, CRP, and IBD antibodies

BACKGROUND

Symptoms of inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) can overlap. We aimed to determine the accuracy of fecal markers, C-reactive protein (CRP), blood leukocytes, and antibody panels for discriminating IBD from IBS and to define a "best test."

METHODS

We prospectively included 64 patients with IBD (36 Crohn's disease [CD], 28 ulcerative colitis [UC]), 30 with IBS, and 42 healthy controls. Besides CRP and blood leukocytes, blinded fecal samples were measured for calprotectin (PhiCal Test, enzyme-linked immunosorbent assay [ELISA]), lactoferrin (IBD-SCAN, ELISA), Hexagon-OBTI (immunochromatographic test for detection of human hemoglobin), and LEUKO-TEST (lactoferrin latex-agglutination test). Blinded serum samples were measured for the antibodies ASCA (ELISA) and pANCA (immunofluorescence).

RESULTS

Overall accuracy of tests for discriminating IBD from IBS: IBD-SCAN 90%, PhiCal Test 89%, LEUKO-TEST 78%, Hexagon-OBTI 74%, CRP 73%, blood leukocytes 63%, CD antibodies (ASCA+/pANCA- or ASCA+/pANCA+) 55%, UC antibodies (pANCA+/ASCA-) 49%. ASCA and pANCA had an accuracy of 78% for detecting CD and 75% for detecting UC, respectively. The overall accuracy of IBD-SCAN and PhiCal Test combined with ASCA/pANCA for discriminating IBD from IBS was 92% and 91%, respectively.

CONCLUSIONS

The PhiCal Test and IBD-SCAN are highly accurate for discriminating IBD from IBS. There is only marginal additional diagnostic accuracy when the PhiCal Test and IBD-SCAN are combined with ASCA and pANCA. ASCA and pANCA have a high specificity for IBD.

A prospective study of faecal calprotectin and lactoferrin in the monitoring of acute radiation proctitis in prostate cancer treatment

OBJECTIVE

Acute radiation proctitis is a relevant complication of pelvic radiation. The purpose of this study was to investigate two markers of gut inflammation as non-invasive diagnostic tools to evaluate acute radiation proctitis.

MATERIAL AND METHODS

Twenty patients who underwent radiotherapy for prostate cancer took part in this prospective study. Radiation-induced toxicity was evaluated weekly during radiotherapy in compliance with the CTC toxicity criteria. Stool samples from patients were examined before treatment, weekly during radiotherapy and 2 weeks after the end of radiotherapy using enzyme-linked immunosorbent assay for calprotectin and lactoferrin and correlated with the CTC toxicity.

RESULTS

Calprotectin and lactoferrin faecal values increased significantly during radiation treatment and decreased about 2 weeks after cessation of radiation. Faecal concentrations of calprotectin and lactoferrin correlated with the documented radiation proctitis symptoms (all grades together) in 15/20 patients (75%). With respect to changes in faecal concentrations and correspondence to proctitis symptoms, both markers showed parallel results in 90% of the patients. On comparing calprotectin and lactoferrin concentrations between the 4th week of radiation and the 1st week, it was found that patients with any grade of toxicity exhibited a significantly higher increase in calprotectin (p = 0.044) and lactoferrin (p = 0.05), respectively, compared with those without toxicity.

CONCLUSIONS

Calprotectin and lactoferrin faecal values changed during radiation treatment and after cessation of radiation, with correlation to acute proctitis symptoms in most of the patients. Before markers are used to monitor acute radiation proctitis, further experience should be acquired. Patients will be followed to determine the predictive value of the two tested markers for chronic radiation proctitis.

Effects of iron loading on muscle: genome-wide mRNA expression profiling in the mouse

Background

Hereditary hemochromatosis (HH) encompasses genetic disorders of iron overload characterized by deficient expression or function of the iron-regulatory hormone hepcidin. Mutations in 5 genes have been linked to this disease: HFE, TFR2 (encoding transferrin receptor 2), HAMP (encoding hepcidin), SLC40A1 (encoding ferroportin) and HJV (encoding hemojuvelin). Hepcidin inhibits iron export from cells into plasma. Hemojuvelin, an upstream regulator of hepcidin expression, is expressed in mice mainly in the heart and skeletal muscle. It has been suggested that soluble hemojuvelin shed by the muscle might reach the liver to influence hepcidin expression. Heart muscle is one of the target tissues affected by iron overload, with resultant cardiomyopathy in some HH patients. Therefore, we investigated the effect of iron overload on gene expression in skeletal muscle and heart using Illumina™ arrays containing over 47,000 probes. The most apparent changes in gene expression were confirmed using real-time RT-PCR.

Results

Genes with up-regulated expression after iron overload in both skeletal and heart muscle included angiopoietin-like 4, pyruvate dehydrogenase kinase 4 and calgranulin A and B. The expression of transferrin receptor, heat shock protein 1B and DnaJ homolog B1 were down-regulated by iron in both muscle types. Two potential hepcidin regulatory genes, hemojuvelin and neogenin, showed no clear change in expression after iron overload.

Conclusion

Microarray analysis revealed iron-induced changes in the expression of several genes involved in the regulation of glucose and lipid metabolism, transcription and cellular stress responses. These may represent novel connections between iron overload and pathological manifestations of HH such as cardiomyopathy and diabetes.

Metabolic and inflammatory faecal markers in collagenous colitis

OBJECTIVES

To evaluate the excretion of the inflammatory and metabolic faecal markers calprotectin, lactoferrin, and short-chain fatty acids in symptomatic and quiescent collagenous colitis.

METHODS

Faecal samples from 21 patients with active collagenous colitis, 12 patients retested in remission, and 13 controls were analysed. Calprotectin was determined using an enzyme-linked immunosorbent assay. Lactoferrin was estimated by a latex agglutination test. Short-chain fatty acids were determined by steam distillation followed by gas-liquid chromatography.

RESULTS

Calprotectin was increased in patients with active collagenous colitis [80 microg/g (6.25-1899)] (median and range) compared with patients with quiescent collagenous colitis [26 microg/g (6.25-340)], P=0.025 and controls [6.25 microg/g (6.25-99)], P=0.002. Eight patients (38%) with active collagenous colitis had normal levels of calprotectin. Lactoferrin was detected in one patient only. Concentrations of total short-chain fatty acids did not differ in patients with active collagenous colitis compared with quiescent collagenous colitis or controls (P=0.75), whereas concentrations of the branched-chain fatty acids were decreased in patients with active collagenous colitis versus controls (P<0.005). In-vitro incubations demonstrated increased ratios of acetate in patients with active and quiescent collagenous colitis compared with controls (P<0.05), with a corresponding decrease in branched-chain fatty acids ratios (P<0.05).

CONCLUSION

Faecal calprotectin was increased in collagenous colitis; however, increased excretion was not a universal finding limiting the use of calprotectin as an inflammatory marker in collagenous colitis. Faecal lactoferrin was almost undetectable. Luminal fermentative conditions are altered in collagenous colitis. Fermentative alterations could be secondary to changes in substrate availability and intestinal transit time.

Fecal calprotectin in very low birth weight infants

OBJECTIVES

To measure concentrations of fecal calprotectin (f-calprotectin) in infants with very low birth weight (VLBW; <1500 g) longitudinally and to describe changes in f-calprotectin in infants who develop severe abdominal disease.

PATIENTS AND METHODS

The study included 59 VLBW infants. Seven patients (disease group) developed severe abdominal disease defined as necrotizing enterocolitis (NEC) or a condition leading to laparotomy. The remainder (n = 52) were considered reference infants and had a mean (+/-SD) gestational age of 27.2 +/- 2.6 weeks and a birth weight of 939 +/- 273 g. F-calprotectin was analyzed in meconium and weekly during postnatal weeks 1 to 8. In disease cases, more frequent samples were analyzed around the time of abdominal disease diagnosis.

RESULTS

In reference infants the median (range) f-calprotectin level in meconium was 332 (12-9386) microg/g and correlated negatively to Apgar score. F-calprotectin in postmeconium samples was 253 (9-1867) microg/g and correlated positively to delivery by cesarean section, postnatal age, and volume of enteral feeds, and negatively to treatment with antibiotics and corticosteroids. In reference infants no postmeconium sample had f-calprotectin levels >2000 microg/g. In disease cases f-calprotectin was increased to >2000 microg/g in 3 cases of NEC and 1 case of covered perforation with microscopic bowel inflammation. In 1 case of NEC without microscopic bowel inflammation and 2 cases of focal intestinal perforation, f-calprotectin levels never exceeded 2000 microg/g.

CONCLUSIONS

F-calprotectin concentrations in VLBW infants are similar to previously reported levels in healthy term and moderately preterm infants. An f-calprotectin level >2000 microg/g is a useful but not an early marker of NEC and other severe intestinal inflammatory conditions in VLBW infants.

Diagnostic precision of fecal calprotectin for inflammatory bowel disease and colorectal malignancy

OBJECTIVES

Fecal calprotectin (FC) is a relatively new marker of intraluminal intestinal inflammation. Using meta-analytical techniques, the study aimed to evaluate the diagnostic precision of FC for inflammatory bowel disease (IBD) and colorectal cancer (CRC) in adults and children.

METHODS

Quantitative meta-analysis was performed on prospective studies, comparing FC levels against the histological diagnosis. Sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated for each study. Summary receiver-operating characteristic (sROC) curves and subgroup analysis were undertaken. Study quality and heterogeneity were evaluated.

RESULTS

Thirty studies of 5,983 patients were included. FC levels in patients with IBD were higher by 219.2 micrograms per gram (microg/g) compared with normal patients (P < 0.001). sROC curve analysis showed a sensitivity of 0.95 (95% CI 0.93-0.97), specificity of 0.91 (95% CI 0.86-0.91), and an area under the curve (AUC) of 0.95 for the diagnosis of IBD. Patients with colorectal neoplasia had nonsignificantly higher FC levels by 132.2 microg/g compared with noncancer controls (P= 0.18). Sensitivity and specificity of FC for the diagnosis of CRC were 0.36 and 0.71, respectively, with an AUC of 0.66. The diagnostic precision of FC for IBD was higher in children than adults with better accuracy at a cutoff level of 100 microg/g versus 50 microg/g. Sensitivity analysis and metaregression analysis did not significantly alter the results.

CONCLUSIONS

FC cannot be recommended as a screening test for CRC in the general population. FC appeared to offer a good diagnostic precision in distinguishing IBD from non-IBD diagnoses, with higher precision at a cutoff of 100 microg/g.

Quantification of S100A12 (EN-RAGE) in Blood Varies with Sampling Method, Calcium and Heparin

S100A12 is a calcium-binding protein predominantly found in neutrophil granulocytes and monocytes. Its usefulness in monitoring inflammatory disease states depends on documentation that assay results are reliable. This study aimed at defining guidelines for blood sampling, selection of optimal material handling and reference intervals in healthy controls while taking into account the basic features of S100A12. An enzyme linked immunosorbent assay was developed based upon antibodies induced in rabbits by injection of recombinant S100A12. Our studies confirm that oligomers of S100A12 are generated in the presence of calcium. Structural changes in S100A12 mediated by calcium influence the interaction with antibody. This is proposed as the background for our very low readings of S100A12 in Ethylene Diamine Tetraacetic Acid (EDTA) plasma. Individual S100A12 levels did not change substantially over a 5-week sampling period. Based upon testing of 150 blood donors we suggest reference intervals of S100A12 in serum to be 49-1340 microg/l for women and 27-1750 microg/l for men. The estimated mean concentrations were 234 microg/l in serum samples (range 12-15791), 114 microg/l (range 3-17282) in re-calcified EDTA plasma and 48 microg/l (range 2-14843) in heparin plasma. Without adding calcium to EDTA plasma before running the assay, concentrations were around 2 microg/l (16 persons). S100A12 quantification is assumed to become relevant for diagnostic use in many disease states. The importance of the handling and analysing conditions for a reliable result was examined. We recommend serum collected in gel-containing tubes as the preferred sample material and have suggested reference intervals for healthy individuals.

Calprotectin (a major leucocyte protein) is strongly and independently correlated with joint inflammation and damage in rheumatoid arthritis

OBJECTIVE

Calprotectin is a major leucocyte protein, shown to correlate well with laboratory and clinical assessments in several inflammatory rheumatic diseases, and large concentrations of calprotectin have been found in synovial fluid from patients with rheumatoid arthritis (RA). The objective of the present study was to examine correlations between calprotectin and joint damage.

METHODS

145 patients with RA were analysed cross sectionally with laboratory (calprotectin, C reactive protein (CRP), and erythrocyte sedimentation rate (ESR)), clinical (28 joint counts (tender, swollen), physician global VAS, DAS28 and RA Articular Damage score (RAAD)), and radiographic (plain hand radiographs; modified Sharp's method) measurements, on the same day.

RESULTS

Calprotectin showed a highly significant correlation with measures of joint damage; modified Sharp score r = 0.43 (p<0.001) and RAAD r = 0.40 (p<0.001). The association with modified Sharp score and RAAD score was maintained after adjustment for CRP, ESR, rheumatoid factor, DAS28, sex, and age in a multiple regression analysis (p = 0.018 and p = 0.04, respectively), while neither CRP nor ESR showed any independent associations. Highly significant correlations (p<0.001) were also found between calprotectin and both laboratory and clinical markers of inflammation.

CONCLUSION

Calprotectin was found to significantly and independently explain the variation in the radiological and clinical assessments of joint damage. Longitudinal studies are required to examine whether calprotectin may predict the progression of joint damage in RA.

Calprotectin in microglia from frontal cortex is up-regulated in schizophrenia: evidence for an inflammatory process?

Schizophrenia is associated with a number of pathological changes, including alterations in levels of specific proteins. Calprotectin is a novel 36 kDa calcium-binding protein of the S100 family and appears to be a nonspecific marker of inflammation. Calprotectin has not previously been investigated in brain tissue. Samples of post-mortem brain tissue from Brodmann area 9 were obtained from prefrontal cortex from subjects with schizophrenia, bipolar affective disorder, major depression, and from controls. Calprotectin levels were determined by ELISA. To determine cellular localization, immunocytochemical and fluorescent double-labelling analyses were performed. Exogenous calprotectin was added to retinoic acid-differentiated human SH-SY5Y neuroblastoma cell cultures in order to investigate mechanisms of action of calprotectin. Calprotectin was detectable in all samples, and mean levels were noted to be highest in schizophrenic brains (P < 0.05) and lowest in controls. Levels were intermediate in bipolar affective disorder and major depression. Exogenous calprotectin appeared to induce dendritic extension in SH-SY5Y cell culture in a dose-dependent manner. Calprotectin was found to be localized to microglia. These findings suggest that increased levels of calprotecitn in the brain may reflect inflammatory processes, which play a role in the pathogenesis of major psychiatric disorders. Furthermore, calprotectin may influence dendritic plasticity.