Elevated fecal M2-pyruvate kinase in children with cystic fibrosis: a clue to the increased risk of intestinal malignancy in adulthood?

BACKGROUND AND AIM: Adult patients with cystic fibrosis (CF) have an increased risk of gastrointestinal malignancies. We hypothesized that increased intestinal cell turnover beginning in childhood may explain the increased risk of malignancy in early adulthood. Therefore, we aimed to measure fecal M2-pyruvate kinase (M2-PK), a biomarker of intestinal cell turnover, in children with CF. To assess whether the increased cell turnover is secondary to intestinal inflammation, the secondary aims were to measure fecal calprotectin and evaluate its association with fecal M2-PK. METHODS: Fecal samples, for M2-PK and calprotectin measurements, were prospectively collected from children with CF and healthy controls (HC). RESULTS: Thirty-three children with CF (mean [standard deviation] 7.3 [3.8] years old; 29 pancreatic insufficient [PI]) were enrolled and compared with 33 age-matched HC. Fecal M2-PK in CF patients (median [interquartile range, IQR]: 4.7 [1.5-9.7]) was greater than HC (1.0 [1.0-1.0] U/mL; P < 0.0001), and higher in PI (median [IQR]: 5.1 [1.8-13.7]) than pancreatic sufficient patients (1.0 [1.0-1.0] U/mL; P = 0.002). Fecal calprotectin was significantly elevated in CF than HC (median [IQR] 61.3 [43.8-143.8] vs 19.5 [19.5-35.1] mg/kg; P < 0.0001). However, there was no correlation between fecal M2-PK and fecal calprotectin levels among subjects with CF (r = 0.29; P = 0.1). CONCLUSION: Increased intestinal cell turnover is present in children with PI CF. The lack of relationship between fecal M2-PK and calprotectin suggests that contributing factor(s) other than inflammation may be present.

Intestinal inflammation and impact on growth in children with cystic fibrosis.

OBJECTIVE: The aim of the study was to evaluate and compare faecal markers of intestinal inflammation in children with cystic fibrosis (CF), and determine whether intestinal inflammation adversely affects the nutritional phenotype. METHODS: Faecal samples for markers of intestinal inflammation, calprotectin, S100A12, and osteoprotegerin, were collected from children with CF, healthy controls (HCs), and Crohn disease (CD). Associations between inflammatory markers and clinical and nutritional indices were determined in subjects with CF. RESULTS: Twenty-eight children with CF (mean [standard deviation (SD)] 8.4 [3.3] years old, 22 pancreatic insufficient [PI]), 47 HC, and 30 CD were recruited. Mean (SD) faecal calprotectin in CF (94.3 [100.6] mg/kg) was greater than HC (26.7 [15.4] mg/kg, P < 0.0001), but lower than CD (2133 [2781] mg/kg, P = 0.0003). Abnormal faecal calprotectin was found in subjects only with PI (17/22 (77%), P = 0.001). There was no difference in faecal mean (SD) S100A12 (0.8 [0.9] vs 1.5 [2.2] mg/kg, P = 0.14) and osteoprotegerin concentrations (72.7 [52.2] vs 62.5 [0.0] pg/mL, P = 0.2) between CF and HC. Patients with CD had significantly elevated S100A12 and osteoprotegerin compared with CF and HC. Faecal calprotectin inversely correlated with both weight (r = -0.5, P = 0.003) and height z scores (r = -0.6, P = 0.002) in CF. CONCLUSIONS: The pattern of intestinal inflammation in CF is unique and distinct from inflammatory bowel disease, with elevated faecal calprotectin but normal faecal S100A12 and osteoprotegerin concentrations. The severity of intestinal inflammation, based on faecal calprotectin, significantly correlates with poor growth.

Fecal Human ß-Defensin 2 in Children with Cystic Fibrosis: Is There a Diminished Intestinal Innate Immune Response?

BACKGROUND: Defects in bacterial host defenses in the cystic fibrosis (CF) airways have been extensively investigated, but the role of the intestinal innate immune system in CF is unknown. Human ß-defensin 2 (HBD-2) is an antimicrobial protein produced by epithelial surfaces and upregulated by inflammation. Its expression in the CF intestine is unknown. AIM: To determine whether HBD-2 was present in the feces of patients with CF, and to compare fecal HBD-2 levels between CF and healthy controls (HC). To compare fecal HBD-2 levels in inflamed and noninflamed states, as measured by fecal calprotectin, as a secondary aim. METHODS: Feces from children with CF and HC were collected for analysis. RESULTS: Thirty-three CF patients and 33 HC were recruited. All CF patients had detectable fecal HBD-2. There was no difference between fecal HBD-2 in CF and HC (median (IQR) 49.1 (19.7-77.2) versus 43.4 (26.5-71.9) ng/g; P = 0.7). Fecal calprotectin was significantly higher in the CF cohort than in HC (median (IQR) 61.3 (43.8-143.8) versus 19.5 (19.5-35.1) mg/kg; P < 0.0001). There was no difference in fecal HBD-2 levels between CF subjects with fecal calprotectin ≥50 mg/kg and <50 mg/kg (50.5 (19.6-80.2) versus 43.0 (19.0-70.4); P = 0.7). There was no correlation between fecal HBD-2 and calprotectin in CF (r = 0.14; P = 0.4). CONCLUSION: Fecal HBD-2 levels were not increased in children with CF, in inflamed or noninflamed states. The lack of HBD-2 induction and upregulation under inflammatory conditions may suggest a diminished intestinal innate immune response in CF.

Effect of alternative intravenous lipid emulsion in clinical outcome in non-critically ill patients.

INTRODUCTION: Most studies on alternative intravenous lipid emulsion (IVLE) versus conventional IVLE have been conducted in the critically ill patients. The benefits of alternative IVLE in non-critically ill patients is uncertain. We aim to determine clinical outcome difference between alternative IVLE versus conventional IVLE in non-critically ill patients. METHOD: All patients on parenteral nutrition (PN) from July 2007 to September 2010 were identified. Patients were stratified into two groups: conventional IVLE (soybean oil-based) and alternative IVLEs, namely MCT oil-based, olive oil-based and fish oil-containing IVLE. RESULT: Three hundred and eighty-eight patients were included in the study. Ninety-one patients received soybean-based IVLE, 59 patients received MCT oil-based IVLE, 141 patients received olive oil-based IVLE and 97 patients received fish oil-containing IVLE. Adjusting the effect of baseline covariates in separate multiple linear/logistic regression models, there were no differences in mortality, readmission, length of stay and infection between conventional IVLE group and alternative IVLEs group, the adjusted p-value was 0.64, 0.06, 0.36 and 0.18 respectively. However, there was a significant change in day 5 CRP between these two groups (8.43 g/L (SD 112.2) vs -41.2 (SD 106.4); adjusted p-value = 0.01). There was no difference in day 5 albumin between these two group (-1.03 (SD 5.1) vs -0.1 (SD 5.3); adjusted p-value = 0.08). CONCLUSION: Our study showed that pertinent clinical outcomes in non-critically ill patients who received either conventional IVLE or alternative IVLEs were the same. However, there was significant reduction in day-5 CRP in alternative IVLE compared to conventional IVLE.

Age-related levels of fecal M2-pyruvate kinase in children with cystic fibrosis and healthy children 0 to 10years old.

BACKGROUND: The pathogenesis of gut inflammation, bacterial dysbiosis and increased rates of malignancy in CF is unclear. Fecal M2-pyruvate kinase (M2-PK) is a biomarker indicative of cellular proliferation that may be raised in intestinal malignancy and inflammation. Biomarkers, including M2-PK, may be useful in assessing effects of novel therapies on the gastrointestinal tract. METHODS: M2-PK was measured in stools collected from patients with CF and HC (0-10years). Linear mixed model analysis was used. RESULTS: M2-PK levels did not significantly change in children with CF (36 patients, 77 samples) (P=0.998) or HC (45 patients, 45 samples) (P=0.21), over the age range 0-10years. Patients with CF had elevated M2-PK compared to HC (median [IQR; range]: 10.7 [5.7-28.6; 1.0-239.1] (n=77) vs. 1.0 [1.0-1.0; 1.0-50.0] (n=45) U/mL, respectively; P=0.001). CONCLUSIONS: Fecal M2-PK was elevated in children with CF compared with HC during infancy and throughout childhood suggesting abnormalities in the CF gut exist in early life.

Age-dependent variation of fecal calprotectin in cystic fibrosis and healthy children.

BACKGROUND: Fecal calprotectin may be used as a non-invasive method to assess the effect of novel therapies on the gut in cystic fibrosis (CF). METHOD: Stools from CF patients and healthy controls (HC) (0-10years old) were prospectively collected for evaluation of temporal trends. RESULTS: 130 CF samples (64 subjects) and 114 HC samples (101 subjects) were collected. Overall, fecal calprotectin levels were different in CF patients and HC from 0 to 10years (P=0.0002). Fecal calprotectin in CF was significantly lower than HC from 0 to 1years (P=0.03) and demonstrated an upward trajectory until 4years. From >4 to 10years calprotectin was consistently higher in CF patients compared with HC (P=0.007). CONCLUSIONS: Fecal calprotectin levels in children with CF and HC were age-dependent and had distinct trajectories. Careful interpretation of calprotectin is required if used in drug trials for CF, particularly in children less than 4years old.

Fecal biomarkers of intestinal health and disease in children.

The identification of various fecal biomarkers has provided insight into the intestinal milieu. Most of these markers are associated with the innate immune system of the gut, apart from the more novel M2-pyruvate kinase. The innate immunity of the gut plays a role in maintaining a fine balance between tolerance to commensal bacteria and immune response to potential pathogens. It is a complex system, which comprises of multiple elements, including antimicrobial peptides (e.g., defensins, cathelicidins, lactoferrin, and osteoprotegerin), inflammatory proteins (e.g., calprotectin and S100A12), and microbial products (e.g., short-chain fatty acids). Dysfunction of any component can lead to the development of intestinal disease, and different diseases have been associated with different fecal levels of these biomarkers. Each fecal biomarker provides information on specific biological and disease processes. Therefore, stool quantification of these biomarkers provides a non-invasive method to define potential pathways behind the pathogenesis of diseases and can assist in the assessment and diagnosis of various gastrointestinal conditions. The abovementioned fecal biomarkers and their role in intestinal health and disease will be reviewed in this paper with a pediatric focus.