Glucose breath test for the detection of small intestine bacterial overgrowth: Impact of diet prior to the test.

BACKGROUND: Glucose breath test (GBT) is used for the diagnosis of small intestine bacterial overgrowth. A restrictive diet without fibers and/or fermentable food is recommended on the day before the test. The aim of our retrospective study was to evaluate the impact of two different restrictive diets on the results of GBT. METHODS: A change of the pretest restrictive diet was applied in our lab on September 1, 2020. The recommended diet was a fiber-free diet before this date, and a fiber-free diet plus restriction of all fermentable food afterward. We thus compared the results of GBT performed before (group A) and after (group B) this pretest diet modification. Demographics, reasons to perform GBT, digestive symptoms, and hydrogen and methane baseline values and variations after glucose ingestion were compared between the two groups. KEY RESULTS: 269 patients underwent GBT in group A, and 316 patients in group B. The two groups were comparable in terms of demographics. Methane and hydrogen baseline values were significantly higher in group A (respectively 14 [18] vs. 8 [14] ppm, p < 0.01 and 11 [14] vs. 6 [8] ppm, p < 0.01). The percentage of positive tests was higher in group A for methane (43% vs. 28%, p < 0.05), and for hydrogen (18% vs. 12%, p = 0.03). CONCLUSION & INFERENCES: This retrospective study suggests the importance of the restrictive diet prior to GBT. A strict limitation of fibers and fermentable food decreased hydrogen and methane baseline values, and the prevalence of positive GBT. Thus a strict restrictive diet should be recommended on the day before the test, in order to limit the impact of food on hydrogen and methane breath levels, and possibly improve the diagnosis quality of GBT.

Metabolic signature of 13C-labeled wheat bran consumption related to gut fermentation in humans: a pilot study.

PURPOSE: The aim of this pilot study was to analyze concomitantly the kinetics of production of 13C-labeled gut-derived metabolites from 13C-labeled wheat bran in three biological matrices (breath, plasma, stools), in order to assess differential fermentation profiles among subjects. METHODS: Six healthy women consumed a controlled breakfast containing 13C-labeled wheat bran biscuits. H2, CH4 and 13CO2, 13CH4 24 h-concentrations in breath were measured, respectively, by gas chromatography (GC) and GC-isotope ratio mass spectrometry (GC-IRMS). Plasma and fecal concentrations of 13C-short-chain fatty acids (linear SCFAs: acetate, propionate, butyrate, valerate; branched SCFAs: isobutyrate, isovalerate) were quantified using GC-combustion-IRMS. Gut microbiota composition was assessed by16S rRNA gene sequencing analysis. RESULTS: H2 and CH4 24 h-kinetics distinguished two groups in terms of fermentation-related gas excretion: high-CH4 producers vs low-CH4 producers (fasting concentrations: 45.3 ± 13.6 ppm vs 6.5 ± 3.6 ppm). Expired 13CH4 was enhanced and prolonged in high-CH4 producers compared to low-CH4 producers. The proportion of plasma and stool 13C-butyrate tended to be higher in low-CH4 producers, and inversely for 13C-acetate. Plasma branched SCFAs revealed different kinetics of apparition compared to linear SCFAs. CONCLUSION: This pilot study allowed to consider novel procedures for the development of biomarkers revealing dietary fiber-gut microbiota interactions. The non-invasive assessment of exhaled gas following 13C-labeled fibers ingestion enabled to decipher distinct fermentation profiles: high-CH4 producers vs low-CH4 producers. The isotope labeling permits a specific in vivo characterisation of the dietary fiber impact consumption on microbiota metabolite production. CLINICAL TRIAL REGISTRATION: The study has been registered under the number NCT03717311 at ClinicalTrials.gov on October 24, 2018.

Impact of prolonged requirement for insulin on 90-day mortality in critically ill patients without previous diabetic treatments: a post hoc analysis of the CONTROLING randomized control trial.

BACKGROUND: Stress hyperglycemia can persist during an intensive care unit (ICU) stay and result in prolonged requirement for insulin (PRI). The impact of PRI on ICU patient outcomes is not known. We evaluated the relationship between PRI and Day 90 mortality in ICU patients without previous diabetic treatments. METHODS: This is a post hoc analysis of the CONTROLING trial, involving 12 French ICUs. Patients in the personalized glucose control arm with an ICU length of stay ≥ 5 days and who had never previously received diabetic treatments (oral drugs or insulin) were included. Personalized blood glucose targets were estimated on their preadmission usual glycemia as estimated by their glycated A1c hemoglobin (HbA1C). PRI was defined by insulin requirement. The relationship between PRI on Day 5 and 90-day mortality was assessed by Cox survival models with inverse probability of treatment weighting (IPTW). Glycemic control was defined as at least one blood glucose value below the blood glucose target value on Day 5. RESULTS: A total of 476 patients were included, of whom 62.4% were male, with a median age of 66 (54-76) years. Median values for SAPS II and HbA1C were 50 (37.5-64) and 5.7 (5.4-6.1)%, respectively. PRI was observed in 364/476 (72.5%) patients on Day 5. 90-day mortality was 23.1% in the whole cohort, 25.3% in the PRI group and 16.1% in the non-PRI group (p < 0.01). IPTW analysis showed that PRI on Day 5 was not associated with Day 90 mortality (IPTWHR = 1.22; CI 95% 0.84-1.75; p = 0.29), whereas PRI without glycemic control was associated with an increased risk of death at Day 90 (IPTWHR = 3.34; CI 95% 1.26-8.83; p < 0.01). CONCLUSION: In ICU patients without previous diabetic treatments, only PRI without glycemic control on Day 5 was associated with an increased risk of death. Additional studies are required to determine the factors contributing to these results.

Low Levels of Fecal Calprotectin 3 Months After Surgery Predict Subsequent Endoscopic Postoperative Remission in Crohn's Disease.

BACKGROUND/AIMS: In Crohn's disease (CD) few data are available on the usefulness of monitoring fecal calprotectin (FC) in the early postoperative setting. We assessed prospectively the accuracy of FC measured 3 months after surgery to predict the risk of endoscopic postoperative recurrence (POR) within 1 year after resection. METHODS: In 55 consecutive CD patients who had undergone ileocolonic resection samples were collected 3 months after surgery for measuring serum CRP and FC. Endoscopic POR was assessed by ileocolonoscopy within 6-12 months (median 7 months). Receiver operating characteristic (ROC) curves were generated to assess accuracy of the markers, to determine the best threshold and to calculate sensitivity, specificity, positive and negative predictive values. RESULTS: In contrast with median CRP levels, median FC concentrations measured 3 months after surgery were significantly higher in patients who later experienced endoscopic POR (Rutgeerts ≥ i2) compared with those who stayed in endoscopic remission within the following 6-12 months (205 µg/g IQR [106-721] vs. 103 µg/g IQR [60-219], p = 0.008). Area under the ROC curve for FC was 0.71. The best cutoff value of FC to identify patients in subsequent endoscopic remission 3 months after surgery was 65 µg/g (96% sensitivity, 31% specificity, 50% positive and 91% negative predictive values). In multivariate analysis, FC < 65 µg/g at 3 months was the only factor associated with subsequent endoscopic remission. CONCLUSION: FC measured 3 months after surgery below 65 µg/g is an accurate marker to identify CD patients who will later stay in endoscopic remission within 1 year after resection.

Concentrations of Ustekinumab During Induction Therapy Associate With Remission in Patients With Crohn's Disease.

Ustekinumab is approved for treatment of Crohn's disease (CD).1,2 Few data are available to assess the usefulness of monitoring inflammatory biomarkers and therapeutic drug monitoring to predict response to ustekinumab. We conducted a prospective study to assess the relationships between these parameters and the clinical outcome at week 16 in active CD patients receiving ustekinumab.

Accuracies of serum and fecal S100 proteins (calprotectin and calgranulin C) to predict the response to TNF antagonists in patients with Crohn's disease.

BACKGROUND: Calprotectin and S100A12 (calgranulin C) are markers of gut inflammation. The aim was to compare the usefulness of serum and fecal calprotectin (fCal) and S100A12 in assessing the response to anti-TNF and in predicting relapse under maintenance therapy in Crohn's diseases (CD). METHODS: Thirty-two consecutive patients with CD were treated with adalimumab or infliximab. All received an induction regimen followed by maintenance therapy with infliximab 5 mg/kg every 8 weeks or adalimumab 40 mg every other week and provided at week 0 and 14 fecal and blood samples for determination serum CRP, serum and fecal calprotectin and S100A12 levels. RESULTS: Clinical remission at week 14 (responders) was achieved in 21 patients and among them, 12 were still in steroid-free clinical remission at week 52. Median serum S100A12 and fCal concentrations significantly drop only in responders from week 0 to week 14 after induction, whereas serum calprotectin and fecal S100A12 levels failed to differ significantly. Fecal calprotectin levels at week 14 had the highest discriminant validity to predict clinical remission within 1 year after induction (area under the curve = 0.87) followed by fecal, serum S100A12, and serum calprotectin (area under the ROC curve = 0.70, 0.70, and 0.68, respectively). A cutoff of 82 µg/g for fCal at week 14 had a sensitivity and specificity of 93% and 75%, respectively, to predict clinical remission within 1 year of therapy. CONCLUSIONS: Serum S100A12 level and fCal are reliable markers associated with response to induction therapy with anti-TNF. Fecal calprotectin was the best for predicting clinical remission in CD under maintenance therapy.

Overview of the in vitro stability of commonly measured vitamins and carotenoids in whole blood.

BACKGROUND: The pre-analytical stabilities of vitamins A, E, K, B1, B2, B6, B12, C, carotenoids and folates in whole blood were studied. The aim of this work was to provide clear and workable pre-analytical procedures specifying optimal delay before freezing for laboratories which perform themselves such analyses or which receive and transfer such specimens to referral laboratories. METHODS: The stability of vitamins was studied in whole blood at room temperature after light exposure up to 24 h (vitamin C), 48 h (vitamins A, E, B1, B2, B6 and carotenoids) and 72 h (vitamins K, B12, red blood cell (RBC) and serum folates). Vitamin C stability after baseline acidification was analysed up to 48 h. Changes observed were compared to a clinical cut-off defined as total change limit based on a combination of analytical performance and within-subject variation. RESULTS: Clinically and statistically significant changes occurred only in vitamins C (-22.5%), B6 (+9.9%) and serum folates (-16.8%) concentrations after 6, 24 and 48 h, respectively. Vitamins A, E, K, B1, B2, B12, RBC folates and carotenoids showed good stability up to 48 or 72 h. Vitamin C in acidified serum conserved at room temperature appeared unstable. The optimal condition for acidified vitamin C conservation was at less than -20℃. CONCLUSION: The majority of vitamins remain stable for up to 48 h. Vitamin C quantification requires serum acidification followed by freezing as soon as possible. Freezing, respectively, within 12 h and 24 h for determination of plasma vitamin B6 and serum folates concentrations is recommended.

Neopterin is a novel reliable fecal marker as accurate as calprotectin for predicting endoscopic disease activity in patients with inflammatory bowel diseases.

BACKGROUND: Fecal biomarkers have emerged as an important tool for assessing and monitoring disease activity in patients with inflammatory bowel diseases (IBDs). We performed a prospective head-to-head comparison of the diagnostic accuracy of both fecal calprotectin (fCal) and neopterin (fNeo), and serum C-reactive protein in predicting endoscopic disease severity in patients with IBD. METHODS: A total of 133 consecutive patients with IBD (78 Crohn's disease [CD] and 55 ulcerative colitis [UC]) undergoing a colonoscopy provided fecal samples for the measurement of fCal and fNeo concentrations and a blood sample for the serum C-reactive protein measurement. Endoscopic disease activities were scored independently according to the Simple Endoscopic Score for CD in patients with CD and to the Rachmilewitz Index in patients with UC. The respective performances of the fecal markers with respect to endoscopic disease severity were assessed by computing correlations, sensitivities, specificities, and overall accuracies at adjusted cutoffs and also test operating characteristics. RESULTS: The fCal and fNeo concentrations differed significantly in clinically and endoscopically active IBD when compared with those in patients with inactive disease. Both fCal and fNeo concentrations correlated closer with endoscopic scores in UC (r = 0.75 and r = 0.72, respectively; P < 0.0001 for both) than in CD (r = 0.53 and r = 0.47, respectively; P < 0.0001 for both). Using cutoffs of 250 µg/g for fCal and 200 pmol/g for fNeo, both fecal markers had similar overall accuracies to predict endoscopic activity in patients with CD (74%) and also a higher and similar accuracies (88% and 90%, respectively) in patients with UC, whereas accuracies of C-reactive protein were slightly lower in patients with CD and UC. CONCLUSIONS: The fNeo is a novel reliable surrogate biomarker with the potential to identify patients with IBD with active mucosal lesions and represents an alternative marker as accurate as fCal to predict and monitor the severity of mucosal damages in patients with IBD.

Obestatin and ghrelin interplay in hemodialysis patients.

OBJECTIVE: Compounds involved in the regulation of appetite and body composition appear to be of interest in chronic kidney disease. The purpose of this study was to analyze plasma obestatin and acyl and des-acyl ghrelin in patients on hemodialysis (HD). METHODS: Fifty patients on HD (56.0% women, mean age 62.2 ± 15.2 y) were studied. Blood samples were collected during fasting, before a regular HD session. Serum acyl and des-acyl ghrelin levels, leptin, and obestatin were measured using enzyme immunometric assay methods. Anthropometric parameters, appetite score, and food intake were recorded. RESULTS: Patients showed elevated serum leptin (34.1 ± 30 ng/mL), normal acyl ghrelin (137 ± 116.5 pg/mL), high des-acyl ghrelin (670 ± 479 pg/mL), and low obestatin (2.0 ± 1.4 ng/mL) levels compared with healthy volunteers. According to body mass index (BMI), patients with a BMI >23 kg/m(2) had significantly lower plasma obestatin. In contrast, leptin levels were increased and acyl ghrelin tended to be higher in these patients. There was a strong positive correlation between obestatin and des-acyl ghrelin (r = 0.56, P = 0.0001) and inverse correlations between obestatin and BMI (r = -0.40, P = 0.007), waist circumference (r = -0.38, P = 0.024), and C-reactive protein (r = -0.29, P = 0.048). By multivariate analysis, obestatin was independently and positively correlated with des-acyl ghrelin (P = 0.01), but not with C-reactive protein, BMI, or waist circumference. CONCLUSION: In summary, patients on HD exhibited increased plasma levels of des-acyl ghrelin, normal acyl ghrelin levels, and low obestatin levels. In lean patients, the obestatin and des-acyl ghrelin levels were increased, suggesting that these hormones may influence appetite and body composition in patients on HD.