This study describes methods for extraction and quantification of calprotectin (L1 protein) in feces by enzyme immunoassay. This protein is a prominent antimicrobial component of neutrophils, monocytes, macrophages, and squamous epithelia. Calprotectin was stable in feces during storage for 7 days at room temperature. Small fecal samples taken from a 24-h feces collection gave a reliable estimate of calprotectin. Within-assay precision was 1.9%, and between-assay precision 14.8%. In healthy subjects (n = 33) median fecal calprotectin was 2025 micrograms/l and in hospital controls (n = 40) 10,500 micrograms/l. Median values in patients with Crohn's disease (n = 21) was 43,000 micrograms/l and in ulcerative colitis (n = 17) 40,000 micrograms/l. Fecal calprotectin was significantly correlated to fecal alpha 1-antitrypsin in the patients with Crohn's disease. Ten of 11 patients with gastrointestinal carcinomas had calprotectin level above the suggested reference limit of 6740 micrograms/l.
In white cells correlated significantly with faecal calprotectin concentrations. In the group of 312 patients on NSAIDs faecal calprotectin concentrations were significantly higher than in controls, the prevalence of NSAID enteropathy being 44%. The prevalence and severity of NSAID enteropathy was independent of the particular type or dose of NSAID being taken or other patient variables. Conclusions-Assay of faecal calprotectin provides a simple practical method for diagnosing NSAID enteropathy in man. Forty four per cent of patients receiving these drugs had NSAID induced enteropathy when assessed by this technique; 20% of these had comparable levels of inflammation to that previously reported in patients with inflammatory bowel disease. (Gut 1999;45:362-366)
The mechanisms by which the lifestyle risk factors obesity, physical inactivity, and low fiber intake predispose to colorectal cancer (CRC) are unclear. Chronic bowel inflammation predisposes to malignancy in cases of inflammatory bowel disease. Many lifestyle risk factors for CRC are associated with evidence of systemic inflammation as indicated by circulating levels of Creactive protein (CRP), but it is unknown how this relates to inflammation at tissue level. Little is known about the degree of bowel inflammation in general population and the factors that affect it. Therefore, we aimed to assess the relation of levels of bowel inflammation in the general population and lifestyle risk factors for CRC, and to additionally assess whether these associations, if present, were attenuated by controlling for evidence of systemic inflammation.Average CRC risk subjects (320) of either sex aged 50 -70 were recruited in South London. A stool sample was provided for calprotectin measurement (a marker of bowel inflammation), serum for CRP, and a detailed dietary and lifestyle questionnaire completed.There was a significant positive relationship between fecal calprotectin and increasing age (P ؍ 0.002), obesity (P ؍ 0.04), physical inactivity (P ؍ 0.01), and an inverse relationship with fiber intake (P ؍ 0.02) and vegetable consumption (P ؍ 0.04). The relationship with obesity was attenuated by controlling for serum CRP.Fecal calprotectin levels are associated with lifestyle risk factors for colorectal cancer. Low-level asymptomatic bowel inflammation may be the link between lifestyle and the pathogenesis of CRC, and circulating proinflammatory cytokines may be part of the mechanism for this link.
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.
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