Faecal calprotectin: non-invasive marker of gastrointestinal inflammation in Salmonella infected rats

Protective efficacy of fish oil nanoemulsion against non-typhoidal Salmonella mediated mucosal inflammation and loss of barrier function

Non-typhoidal Salmonella serotypes are well-adapted to utilize the inflammation for colonization in mammalian gut mucosa and bring down the integrity of the epithelial barrier in mammalian intestine. The present study...

Experimental infectious challenge in pigs leads to elevated fecal calprotectin levels following colitis, but not enteritis

BACKGROUND

Fecal calprotectin is largely applied as a non-invasive intestinal inflammation biomarker in human medicine. Previous studies in pigs investigated the levels of fecal calprotectin in healthy animals only. Thus, there is a knowledge gap regarding its application during infectious diarrhea. This study investigated the usefulness of fecal calprotectin as a biomarker of intestinal inflammation in Brachyspira hyodysenteriae and Salmonella Typhimurium infected pigs.

RESULTS

Fecal samples from pigs with colitis (n = 18) were collected from animals experimentally inoculated with B. hyodysenteriae (n = 8) or from sham-inoculated controls (n = 3). Fecal samples from pigs with enteritis (n = 14) were collected from animals inoculated with Salmonella enterica serovar Typhimurium (n = 8) or from sham-inoculated controls (n = 4). For both groups, fecal samples were scored as: 0 = normal; 1 = soft, wet cement; 2 = watery feces; 3 = mucoid diarrhea; and 4 = bloody diarrhea. Fecal calprotectin levels were assayed using a sandwich ELISA, a turbidimetric immunoassay and a point-of-care dipstick test. Fecal calprotectin levels were greater in colitis samples scoring 4 versus ≤ 4 using ELISA, and in feces scoring 3 and 4 versus ≤ 1 using immunoturbidimetry (P < 0.05). No differences were found in calprotectin concentration among fecal scores for enteritis samples, regardless of the assay used. All samples were found below detection limits using the dipstick method.

CONCLUSIONS

Fecal calprotectin levels are increased following the development of colitis, but do not significantly change due to enteritis. While practical, the use of commercially available human kits present sensitivity limitations. Further studies are needed to validate the field application of calprotectin as a marker of intestinal inflammation.

Evaluation of a fluorescent immunochromatography test for fecal calprotectin

BACKGROUND

Fecal calprotectin (FC) is widely used to discriminate between patients with inflammatory diseases such as inflammatory bowel disease (IBD) and functional diseases such as irritable bowel syndrome (IBS). ELISA is a time-consuming method for the measurement of FC, whereas a fluorescent immunochromatography test can obtain results in around 30 minutes and thus enables a rapid response to clinical decision.

METHODS

Two methods, the Proglead^® calprotectin (FC Proglead) and the BÜHLMANN fCAL^® ELISA (FC BÜHLMANN), were used to quantitatively examine FC in 111 stool samples. The comparison and bias estimation of both assays were assessed using CLSI EP09c protocol.

RESULTS

The two methods were highly correlated (rho = .96). Deming regression was employed to calculate the regression equation, with a slope of 1.01 and an intercept of -4.98 μg/g. The estimated median bias (FC Proglead - FC BÜHLMANN) was -4.19 μg/g with the 95% limits of agreement (-55.59 to 47.21 μg/g), and the estimated median percent bias was -8.71% with the 95% limits of agreement (-50.31% to 32.90%). There was 4.50% (5/111) of values outside the 95% limits of agreement. Percent biases at the FC cutoff values of 50 and 200 μg/g between both methods evaluated by Deming regression were 8.96% and 1.49%, respectively. The biases were all less than the acceptable standard (10%). And, 99.10% of FC results were in agreement between both methods (kappa = .99, P < .001).

CONCLUSIONS

FC Proglead may be used as a suitable alternative to FC BÜHLMANN for the disease activity assessment for patients with IBD, considering its convenience and shorter turnaround time.

Fecal calprotectin as a correlative marker in clinical severity of infectious diarrhea and usefulness in evaluating bacterial or viral pathogens in children

BACKGROUND

Calprotectin is a marker associated with intestinal inflammation. The aim of this study is to explore the diagnostic value of fecal calprotectin in predicting bacterial/viral diarrhea and the application of fecal calprotectin in the clinical course of infectious diarrhea.

METHODS

Patients ages from 3 months to 10 years with infectious diarrhea were enrolled, and from each patient, 2 to 3 stool samples were collected. Fecal calprotectin levels were determined by enzyme-linked immunosorbent assay and compared by pathogen and disease activity. A univariate linear regression was used to determine the correlation between fecal calprotectin and the clinical parameters, and generalized estimating equations (GEEs) were used for the time course analyses.

RESULTS

The data include 451 evaluations for 153 individuals across 3 different time points. The fecal calprotectin level was higher in patients with Salmonella infection (median with range 765 [252-1246] μg/g) or Campylobacter infection (689 [307-1046] μg/g) compared with patients with rotavirus infection (89 [11-426] μg/g), norovirus infection (93 [25-405] μg/g), or adenovirus infection (95 [65-224] μg/g). Fecal calprotectin concentrations were elevated in patients with severe (843 [284-1246] μg/g) or moderate (402 [71-995] μg/g) disease activity compared with those with mild (87 [11-438] μg/g) disease activity (P < 0.05). GEE analysis suggests that fecal calprotectin is correlated with clinical severity (e.g., Vesikari score) and may provide information for disease management.

CONCLUSIONS

Fecal calprotectin levels increased during bacterial infection and as disease severity increased, and its levels on the initial evaluation and follow-up visit are correlated with clinical severity. Fecal calprotectin may be a useful marker for application in children during infectious diarrhea.

IL-1 receptor regulates S100A8/A9-dependent keratinocyte resistance to bacterial invasion

Previously, we reported that epithelial cells respond to exogenous interleukin (IL)-1α by increasing expression of several genes involved in the host response to microbes, including the antimicrobial protein complex calprotectin (S100A8/A9). Given that S100A8/A9 protects epithelial cells against invading bacteria, we studied whether IL-1α augments S100A8/A9-dependent resistance to bacterial invasion of oral keratinocytes. When inoculated with Listeria monocytogenes, human buccal epithelial (TR146) cells expressed and released IL-1α. Subsequently, IL-1α-containing media from Listeria-infected cells increased S100A8/A9 gene expression in naïve TR146 cells an IL-1 receptor (IL-1R)-dependent manner. Incubation with exogenous IL-1α decreased Listeria invasion into TR146 cells, whereas invasion increased with IL-1R antagonist. Conversely, when S100A8/A9 genes were knocked down using short hairpin RNA (shRNA), TR146 cells responded to exogenous IL-1α with increased intracellular bacteria. These data strongly suggest that infected epithelial cells release IL-1α to signal neighboring keratinocytes in a paracrine manner, promoting S100A8/A9-dependent resistance to invasive L. monocytogenes.

Gene expression response of the rat small intestine following oral Salmonella infection

Data on the molecular response of the intestine to the food-borne pathogen Salmonella are derived from in vitro studies, whereas in vivo data are lacking. We performed an oral S. enteritidis infection study in Wistar rats to obtain insight in the in vivo response in time. Expression profiles of ileal mucosa (IM) and Peyer's patches (PP) were generated using DNA microarrays at days 1, 3, and 6 postinfection. An overview of Salmonella-regulated processes was obtained and confirmed by quantitative real-time PCR on pooled and individual samples. Salmonella-induced gene expression responses in vivo are fewer and smaller than observed in vitro, and the response develops over a longer period of time. Few effects are seen at day 1 and mainly occur in IM, suggesting the mucosa as the primary site of invasion. Later, a bigger response is observed, especially in PP. Decreased expression of anti-microbial peptides genes (in IM at day 1) suggests inhibition of this process by Salmonella. Newly identified target processes are carbohydrate transport (increased expression in IM at day 1) and phase I and phase II detoxification (decreased expression at days 3 and 6). Increase of cytokine and chemokine expression occurs at later time points, both in PP and IM. Pancreatitis-associated protein, lipocalin 2, and calprotectin, potential inflammatory marker proteins, showed induced expression from day 3 onward. We conclude that the in vivo gene expression response of the ileum to Salmonella differs to a large extent from the response seen in vitro.

Lack of flagella disadvantages Salmonella enterica serovar Enteritidis during the early stages of infection in the rat

The roles of flagella and five fimbriae (SEF14, SEF17, SEF21, pef, lpf) in the early stages (up to 3 days) of Salmonella enterica serovar Enteritidis (S. Enteritidis) infection have been investigated in the rat. Wild-type strains LA5 and S1400 (fim+/fla+) and insertionally inactivated mutants unable to express the five fimbriae (fim-/fla+), flagella (fim+/fla-) or fimbriae and flagella (fim-/fla-) were used. All wild-type and mutant strains were able to colonize the gut and spread to the mesenteric lymph nodes, liver and spleen. There appeared to be little or no difference between the fim-/fla+ and wild-type (fim+/fla+) strains. In contrast, the numbers of aflagellate (fim+/fla- or fim-/fla-) salmonella in the liver and spleen were transiently reduced. In addition, fim+/fla- or fim-/fla- strains were less able to persist in the upper gastrointestinal tract and the inflammatory responses they elicited in the gut were less severe. Thus, expression of SEF14, SEF17, SEF21, pef and lpf did not appear to be a prerequisite for induction of S. Enteritidis infection in the rat. Deletion of flagella did, however, disadvantage the bacterium. This may be due to the inability to produce or release the potent immunomodulating protein flagellin.