Diego Martines

Calprotectin and lactoferrin in the assessment of intestinal inflammation and organic disease

Background and aimsCalprotectin and lactoferrin are specific neutrophil-derived proteins, which can be measured in the feces because they are released by cells in inflammatory conditions. We evaluated the efficacy of calprotectin and lactoferrin in detecting organic disease as assessed by colonoscopy.MethodsThe study comprised 144 patients undergoing colonoscopy for lower gastrointestinal symptoms (abdominal pain, altered bowel habits, and bloody stools) (67), or inflammatory bowel disease activity, or surveillance for dysplasia (77). A single stool sample was assayed for calprotectin and lactoferrin. The proportion of patients correctly diagnosed with each test and the relationship with endoscopic and histological findings were measured.ResultsFecal excretion of calprotectin significantly correlated with the finding of colonic inflammation at endoscopy, both in ulcerative colitis and in Crohn’s disease (p<0,001 and p<0,008, respectively), while lactoferrin excretion significantly correlated with histological inflammation (p=0.001 and p=0.009 respectively). Recommended cut-off values need to be adjusted in the inflammatory bowel disease group. Overall sensitivity, specificity, positive predictive value, and diagnostic efficacy were 78, 83, 86, and 80% for calprotectin and 80, 85, 87, and 81% for lactoferrin, respectively.ConclusionsFecal calprotectin and lactoferrin appear to be equally recommendable as inflammatory disease markers in patients with lower gastrointestinal symptoms. Both tests are needed to accurately discriminate activity in inflammatory bowel disease patients.

Intestinal Permeability Test as a Predictor of Clinical Course in Crohn's Disease

Objective:The clinical course of Crohns disease is often unpredictable. The aim of this study was to select the most useful parameters able to predict clinical relapses.Methods:One hundred-thirty Crohns disease patients in clinical remission were followed every 4 months for 2 yr or until clinical relapse. Demographic and clinical data were recorded and intestinal permeability (lactulose/mannitol [L/M] test) and biochemical tests (white blood cell count, erythrocyte sedimentation rate, C-reactive protein, α1 acid glycoprotein, and serum iron) were performed at study entry. A subgroup of 54 patients had clinical follow-up and repeated tests every 4 months.Results:Fifty-two patients (40%) relapsed during the 2-yr follow-up. A significant correlation was found between relapse and gender (p= 0.030) but not between relapse and age, extent and type of disease, previous surgery, or therapy. Increased L/M test (p= 0.0001) and decreased serum iron level (p= 0.0057) were associated with clinical relapse. Time-dependent analysis, performed on patients receiving serial evaluation, showed that L/M test alteration was the only variable that could predict a relapse (RR 8.84, 95% confidence interval [CI] 1.41–53.37; p < 0.05).Conclusion:The L/M test identifies Crohns disease patients in apparent remission, but with a high risk of clinical relapse, better than clinical and biochemical indices. Different treatment strategies might be suggested for this subgroup of patients.

Reduced Plasma Antioxidant Concentrations and Increased Oxidative DNA Damage in Inflammatory Bowel Disease

Background: Oxidative stress is believed to play a key role in the pathogenesis of inflammatory bowel disease (IBD)-related intestinal damage. Circulating antioxidants may have a role to play in preventing free radical-mediated tissue injury. Methods: Plasma vitamin A, E and carotenoid concentrations, leukocytic genomic damage and 8-hydroxy-deoxy-guanosine (8-OHdG) concentration were determined in 46 ulcerative colitis (UC) patients, 37 Crohn disease (CD) patients and 386 controls. A 20 ml blood sample was taken from each subject for antioxidant and 8-OHdG measurements. A food frequency questionnaire was administered to a sample of subjects from each group to evaluate daily intake of dietary compounds. Results: Antioxidant concentration was significantly reduced in IBD patients, particularly in those with active disease, with respect to controls ( P < 0.0001). 8-OHdG concentrations were significantly increased in IBD patients compared to controls, independent of disease activity ( P < 0.05). No correlation was found between antioxidant and 8-OHdG concentrations. Carotenoid concentrations were significantly reduced in malnourished IBD patients (0.89 ± 0.14 μmol/l) compared to patients with normal or high body mass index (1.83 ± 0.12 μmol/l; P < 0.05), independent of disease activity or extension. Protein, fruit and vegetable intakes of IBD patients were significantly lower than those of controls. Conclusions: Depletion of antioxidants is likely to be important in the pathophysiology of IBD: UC and CD patients show increased free radical peripheral leukocyte DNA damage and decreased plasma antioxidant defenses. These results indicate the necessity of further studies to establish whether optimal vitamin status may improve the clinical course of UC and CD.BACKGROUND Oxidative stress is believed to play a key role in the pathogenesis of inflammatory bowel disease (IBD)-related intestinal damage. Circulating antioxidants may have a role to play in preventing free radical-mediated tissue injury. METHODS Plasma vitamin A, E and carotenoid concentrations, leukocytic genomic damage and 8-hydroxy-deoxy-guanosine (8-OHdG) concentration were determined in 46 ulcerative colitis (UC) patients, 37 Crohn disease (CD) patients and 386 controls. A 20 ml blood sample was taken from each subject for antioxidant and 8-OHdG measurements. A food frequency questionnaire was administered to a sample of subjects from each group to evaluate daily intake of dietary compounds. RESULTS Antioxidant concentration was significantly reduced in IBD patients, particularly in those with active disease, with respect to controls (P < 0.0001). 8-OHdG concentrations were significantly increased in IBD patients compared to controls, independent of disease activity (P < 0.05). No correlation was found between antioxidant and 8-OHdG concentrations. Carotenoid concentrations were significantly reduced in malnourished IBD patients (0.89 +/- 0.14 micromol/l) compared to patients with normal or high body mass index (1.83 +/- 0.12 micromol/l; P < 0.05), independent of disease activity or extension. Protein, fruit and vegetable intakes of IBD patients were significantly lower than those of controls. CONCLUSIONS Depletion of antioxidants is likely to be important in the pathophysiology of IBD: UC and CD patients show increased free radical peripheral leukocyte DNA damage and decreased plasma antioxidant defenses. These results indicate the necessity of further studies to establish whether optimal vitamin status may improve the clinical course of UC and CD.

Toll-Like Receptor 2 Regulates Intestinal Inflammation by Controlling Integrity of the Enteric Nervous System

BACKGROUND & AIMS In the intestines, Toll-like receptor 2 (TLR2) mediates immune responses to pathogens and regulates epithelial barrier function; polymorphisms in TLR2 have been associated with inflammatory bowel disease phenotype. We assessed the effects of TLR2 signaling on the enteric nervous system (ENS) in mice. METHODS TLR2 distribution and function in the ileal neuromuscular layer of mice were determined by immunofluorescence, cytofluorimetric analysis, immunoprecipitation, and immunoblot analyses. We assessed morphology and function of the ENS in Tlr2(-/-) mice and in mice with wild-type Tlr2 (wild-type mice) depleted of intestinal microbiota, using immunofluorescence, immunoblot, and gastrointestinal motility assays. Levels and signaling of glial cell line-derived neurotrophic factor (GDNF) were determined using quantitative reverse transcriptase polymerase chain reaction, immunohistochemistry, and immunoprecipitation analyses. Colitis was induced by administration of dextran sulfate sodium or 2,4 dinitrobenzensulfonic acid to Tlr2(-/-) mice after termination of GDNF administration. RESULTS TLR2 was expressed in enteric neurons, glia, and smooth muscle cells of the intestinal wall. Tlr2(-/-) mice had alterations in ENS architecture and neurochemical profile, intestinal dysmotility, abnormal mucosal secretion, reduced levels of GDNF in smooth muscle cells, and impaired signaling via Ret-GFRα1. ENS structural and functional anomalies were completely corrected by administration of GDNF to Tlr2(-/-) mice. Wild-type mice depleted of intestinal microbiota had ENS defects and GDNF deficiency, similar to Tlr2(-/-) mice; these defects were partially restored by administration of a TLR2 agonist. Tlr2(-/-) mice developed more severe colitis than wild-type mice after administration of dextran sulfate sodium or 2,4 dinitrobenzensulfonic acid; colitis was not more severe if Tlr2(-/-) mice were given GDNF before dextran sulfate sodium or 2,4 dinitrobenzensulfonic acid. CONCLUSIONS In mice, TLR2 signaling regulates intestinal inflammation by controlling ENS structure and neurochemical coding, along with intestinal neuromuscular function. These findings provide information as to how defective TLR2 signaling in the ENS affects inflammatory bowel disease phenotype in humans.

High plasma levels of α- and β-carotene are associated with a lower risk of atherosclerosis: Results from the Bruneck study

BACKGROUND AND PURPOSE A large number of studies have contributed to the hypothesis that carotenoids, vitamins A and E are protective against atherosclerosis by acting as antioxidants. The aim of this study was to assess the relationship between plasma levels of carotenoids (alpha- and beta- carotene, lutein, lycopene, zeaxanthin, beta-cryptoxanthin), vitamins A and E, and atherosclerosis in the carotid and femoral arteries. METHODS This prospective and cross sectional study involved a randomly selected population sample of 392 men and women aged 45-65 years. Carotid and femoral artery atherosclerosis was assessed by high-resolution duplex ultrasound. RESULTS alpha- and beta- carotene plasma levels were inversely associated with the prevalence of atherosclerosis in the carotid and femoral arteries (P=0.004) and with the 5-year incidence of atherosclerotic lesions in the carotid arteries (P=0.04). These findings were obtained after adjustment for other cardiovascular risk factors (sex, age, LDL (low density lipoproteins), ferritin, systolic blood pressure, smoking, categories of alcohol consumption, social status, C-reactive protein). Atherosclerosis risk gradually decreased with increasing plasma alpha- and beta-carotene concentrations (P=0.004). No associations were found between vitamin A and E plasma levels and atherosclerosis. CONCLUSIONS This study provides further epidemiological evidence of a protective role of high alpha- and beta- carotene in early atherogenesis.

Oxidative DNA damage in the mucosa of ulcerative colitis increases with disease duration and dysplasia.

BackgroundChronic inflammation may contribute to cancer risk through the accumulation of specific products as a result of DNA damage. The role of free radical mediated oxidative DNA damage during inflammation was determined in patients with ulcerative colitis by measuring 8-hydroxydeoxyguanosine (8-OHdG). MethodsPatients with ulcerative colitis were compared according to age, gender, duration and extent of disease, endoscopic and histologic activity, presence or absence of dysplasia/cancer, and biochemical parameters of inflammation. Patients with sporadic colon cancer and irritable bowel syndrome served as controls. Levels of 8-OHdG were assessed by high pressure liquid chromatography with electrochemical detection (mean number of adducts/105 dG residues). ResultsPatients with ulcerative colitis and dysplasia had significantly higher mucosal 8-OHdG concentrations (P = 0.011). 8-OHdG concentrations were significantly higher in older patients (P = 0.010), patients with long-standing disease (P = 0.015), active endoscopic (P = 0.006) or histologic disease (P = 0.003). Covariance analysis showed significant effect of dysplasia on 8-OHdG levels: values higher than 100 adducts/ 105 dG. had a diagnostic value of 80.9% (SE 6.2%). ConclusionsOxidative DNA damage accumulates with the duration of the disease in ulcerative colitis reaching maximal increase if dysplastic lesions are found with possible implications for mutagenic and carcinogenic progression.

Histological features after liver transplantation in alcoholic cirrhotics

BACKGROUND/AIMS Though alcoholic cirrhosis is a common indication for liver transplantation, it carries the risk of alcohol recidivism and consequent graft failure. This study aims to evaluate the effect of alcohol recidivism on survival rates and histological parameters in patients transplanted for alcoholic cirrhosis, with and without hepatitis C virus (HCV) infection. METHODS Fifty-one out of 189 consecutive transplanted patients underwent psychosocial evaluation and liver biopsy at 6 and 12 months, then yearly after transplantation. RESULTS The cumulative 84 month survival rate was identical in patients transplanted for alcoholic (51%) and non-alcoholic cirrhosis (52%). No difference emerged between anti-HCV negative vs. positive alcoholic cirrhosis patients. Psycho-social evaluation revealed alcohol recidivism in 11/34 long-term survivors, but this did not affect overall survival rate in patients with or without HCV. In anti-HCV negative cases, fatty changes and pericellular fibrosis were significantly more common in heavy drinkers than in occasional drinkers and abstainers. When HCV status was considered regardless of alcohol intake, fibrosis was significantly more frequent in patients with HCV. CONCLUSION Alcohol recidivism after transplantation in alcoholic cirrhosis patients does not affect survival, irrespective of HCV status. Fatty changes and pericellular fibrosis are the most relevant histological signs of heavy alcohol intake.

Reliability of endoscopy in the assessment of variceal features: The Italian Liver Cirrhosis Project

In order to evaluate the reliability of the endoscopic assessment of variceal features, 6 skilled endoscopists separately examined 28 patients with liver cirrhosis and varices. Definitions of variceal features were set up on the basis of the classification of the Japanese Research Society for Portal Hypertension. A new item, i.e. oesophageal lumen occupancy, and a semiquantitative rating system of endoscopic findings were introduced. Beyond chance agreement (Kappa index) was poor on the assessment of the extension of blue colour (0.33) and prevalence of cherry red spots or red weal marking (0.17) whereas was fair to good (0.40-0.66; P less than 10(-5)) on the following: location, size, lumen occupancy, presence of blue colour, presence and extension of red colour sign, haematocystic spot. We conclude that the endoscopic assessment of oesophageal varices based on these features is reliable; their prognostic value as predictors of bleeding risk should be prospectively assessed.

Aggregating Phenotype in Lactobacillus crispatus Determines Intestinal Colonization and TLR2 and TLR4 Modulation in Murine Colonic Mucosa

ABSTRACT The colonic microbiota is a major modulator of the mucosal immune system; therefore, its manipulation through supplementation with probiotics may significantly affect the hosts immune responses. Since different probiotics seem to exert various effects in vivo, we tested the relevance of the autoaggregation phenotype on the intestinal persistence of lactobacilli and their ability to modulate the hosts innate immune responses. After 14 days of diet supplementation, the aggregating strain Lactobacillus crispatus M247 but not aggregation-deficient isogenic mutant MU5 was recovered from the feces and colonic mucosa of mice. This observation was confirmed by strain-specific PCR amplification and by Lactobacillus-specific denaturing gradient gel electrophoresis analysis. Indeed, L. crispatus M247 increased Toll-like receptor 2 (TLR2) mRNA levels, while it reduced TLR4 mRNA and protein levels in the colonic mucosa, whereas MU5 was ineffective. In colonic epithelial cells (CMT-93 cells) L. crispatus M247 but not MU5 induced time-dependent extracellular signal-regulated kinase-1 (ERK1) tyrosine phosphorylation and TLR modulation, which were abolished in the presence of PD98059 (an ERK1 inhibitor). To assess the functional relevance of probiotic-induced TLR modulation, we determined the consequences of L. crispatus preexposure on TLR4 (lipopolysaccharide [LPS]) and TLR2 [Pam3Cys-Ser-(Lys)4] ligand-mediated effects in intestinal epithelial cells. Preexposure to L. crispatus M247 blunted LPS-induced interleukin-6 (IL-6) release and inhibition of CMT-93 migration over a wound edge, whereas it enhanced TLR2-mediated IL-10 up-regulation. In summary, the aggregation phenotype is required for L. crispatus persistence in the colon and for modulation of TLR2/TLR4 expression through an ERK-dependent pathway. We speculate that the aggregation phenotype in L. crispatus M247 is required to temper epithelial cell responsiveness to bacterial endotoxins, which thus affects the evolution of intestinal inflammatory processes.

Effect of infusing branched-chain amino acid during incremental exercise with reduced muscle glycogen content.

SummaryThe aim of this study was to investigate whether, when muscle glycogen is reduced, a pre-exercise infusion of branched-chain amino acids (BCAA) modifies exercise performance or the metabolic and respiratory responses to incremental exercise. Six moderately trained volunteers took part in the following protocol on two occasions. On day 1, at 9 a.m. in the postabsorptive state, they performed a graded incremental exercise (increases of 35 W every 4 min) to exhaustion (Ex-1). A meal of 1,000 kcal (4,200 kJ; 60% protein, 40% fat) was consumed at 12 p.m. No food was then allowed until the end of the experiment (20–21 h later). A 90-min period of exercise at alternating high and moderate intensities, designed to deplete muscle glycogen, was performed between 6 p.m. and 7.30 p.m. The morning after (day 2), the subjects randomly received either a mixed solution of BCAA (260 mg × kg−1 × h−1 for 70 min), or saline. They then repeated the graded incremental exercise to exhaustion (Ex-2). Metabolic and respiratory measurements suggested a muscle glycogen-depleted state had been achieved. No significant differences were observed in total work performed, maximal oxygen uptake or plasma ammonia, alanine, and blood pyruvate concentrations in the two treatments. After BCAA infusion, higher blood lactate concentrations were observed at maximal power output in comparison with those during saline [BCAA 4.97 (SEM 0.41) mmol × l−1, Saline 3.88 (SEM 0.47) mmol × l−1,P < 0.05]. In summary, in conditions of reduced muscle glycogen content, after a short period of fasting, BCAA infusion had no significant effect on the total work that could be performed during a graded incremental exercise.