Quantitative determination of faecal fat, nitrogen and water by means of a spectrophotometric technique: near infrared reflectance analysis (NIRA). Assessment of its accuracy and reproducibility compared with chemical methods

Chronic intestinal failure and short bowel syndrome in Crohn’s disease

Chronic intestinal failure (CIF) is a rare but feared complication of Crohn’s disease. Depending on the remaining length of the small intestine, the affected intestinal segment, and the residual bowel function, CIF can result in a wide spectrum of symptoms, from single micronutrient malabsorption to complete intestinal failure. Management of CIF has improved significantly in recent years. Advances in home-based parenteral nutrition, in particular, have translated into increased survival and improved quality of life. Nevertheless, 60% of patients are permanently reliant on parenteral nutrition. Encouraging results with new drugs such as teduglutide have added a new dimension to CIF therapy. The outcomes of patients with CIF could be greatly improved by more effective prevention, understanding, and treatment. In complex cases, the care of patients with CIF requires a multidisciplinary approach involving not only physicians but also dietitians and nurses to provide optimal intestinal rehabilitation, nutritional support, and an improved quality of life. Here, we summarize current literature on CIF and short bowel syndrome, encompassing epidemiology, pathophysiology, and advances in surgical and medical management, and elucidate advances in the understanding and therapy of CIF-related complications such as catheter-related bloodstream infections and intestinal failure-associated liver disease.

A Simple Colorimetric Method to Quantify Total Fecal Oil Using Oil-soluble Dyes in Laboratory Animals and Its Correlation with Liquid Chromatography-Mass Spectrometry Analysis

We developed a colorimetric method for measuring the amount of oil in mouse stool after co-administering an oil-soluble dye. When the amount of oil in the feces calculated from the amounts of Sudan III and Oil Red O was plotted against the amount of oil detected by liquid chromatography-mass spectrometry, the graph was linear, showing a one-to-one correlation between two analyses. This method may be utilized to determine the efficacy of lipase inhibitors, or to assess fat malabsorption in vivo.

Diagnosis of exocrine pancreatic insufficiency in chronic pancreatitis: 13C-Mixed Triglyceride Breath Test versus Fecal Elastase

BACKGROUND

Pancreatic enzyme replacement therapy (PERT) is indicated in case of clinically relevant exocrine pancreatic insufficiency (EPI). Clinical trials addressing PERT have used the coefficient of fat absorption (CFA) to define EPI but this test is cumbersome to perform. Our aim was to compare two easier-to-perform tests to detect clinically relevant EPI: Fecal Elastase-1 (FE-1) and ¹³C-Mixed Triglyceride Breath Test (TGBT).

METHODS

We prospectively included 54 patients with chronic pancreatitis (CP), 24.1% operated, 29.6% had EPI. EPI was defined as a CFA <93%. The sensitivity (Se), specificity (Sp), positive (PPV) and negative (NPV) predictive values for different cut-offs of FE-1 and TGBT were calculated.

RESULTS

The area under the ROC curve for FE-1/TGBT was 0.861/0.876 for the global sample, 0.842/0.794 for non-operated patients and 0.917/1 for operated patients respectively. Se, Sp, PPV and NPV for a cut-off of FE-1 <200 μg/g were 93.8%, 63.2%, 51.7% and 96% respectively. The best cut-off point for FE-1 was 84 μg/g, which yielded an 87.5% Se, 81.6% Sp, 66.7% PPV and 93.9% NPV. The same parameters for a TGBT <29% were 81.3%, 84.2%, 68.4% and 91.4% respectively. The best cut-off point for TGBT was <23%, which yielded an 81.3% Se, 94.7% Sp, 86.7% PPV and 92.3% NPV. Diabetes was associated to decreased FE-1 levels, even in multivariate analysis.

CONCLUSIONS

FE-1 and TGBT showed similar results for the diagnosis of EPI in CP. In non-operated CP patients, TGBT does not offer any advantage to FE-1 but in operated CP patients TGBT seems a more accurate test.

Modification of stool's water content in constipated infants: management with an adapted infant formula

Background

Constipation is a common occurrence in formula-fed infants. The aim of this preliminary study was to evaluate the impact of a formula with high levels of lactose and magnesium, in compliance with the official regulations, on stool water content, as well as a parental assessment of constipation.

Materials and methods

Thirty healthy term-born, formula-fed infants, aged 4-10 weeks, with functional constipation were included. All infants were full-term and fed standard formula. Exclusion criteria were preterm and/or low birth weight, organic constipation, being breast fed or fed a formula specially designed to treat constipation. Stool composition was measured by near-infrared reflectance analysis (NIRA) and parents answered questions about crying associated with defecation and stool consistency at baseline and after two weeks of the adapted formula.

Results

After 2 weeks of the adapted formula, stool water content increased from 71 +/- 8.1% to 84 +/- 5.9%, (p < 0.02). There was no significant change in the stool's fat, protein or carbohydrate content. Parental impressions of constipation were improved with the decrease in stool hardness (100% with hard stools at baseline, 10% after 2 weeks), pain with defecation (90% at baseline, 10% after 2 weeks), and the requirement for rectal stimulation to achieve defecation (70% at baseline, 30% after 2 weeks, p < 0.001 for all three indicators).

Conclusions

This preliminary study suggests that an adapted formula with high levels of lactose and magnesium increases stool water content and improves symptoms of constipation in term-born, formula-fed infants. A larger randomized placebo-controlled trial is indicated.

[Safety and efficacy of polyethylene glycol 3350 plus electrolytes for the treatment of functional constipation in children]

INTRODUCTION

Polyethylene glycol 3350 plus electrolytes (PEG+E) efficacy has been validated in some studies, but not many have evaluated its safety in children. The aim of our study was to evaluate the safety; renal, malabsorption or excessive production of gas and efficacy of PEG+E treatment in our paediatric population.

PATIENTS AND METHODS

Fifteen patients who suffered functional constipation (Rome III criteria) were evaluated. Median age was 6.2 years (r 2-9). All patients had normal renal function. PEG+E were administered for 4 weeks (4WP). The mean dose was 0.44 g/kg/day, titrated according to age, weight and response. Urine screens (sodium and osmolality) were performed at the beginning and 4WP. Stool sample NIRA (near-infrared reflectance analysis) and hydrogen breath test analysis samples were performed at 4WP. To analyse the efficacy of the treatment, the number of stools per week and stool form type (Bristol stool scale) were recorded.

RESULTS

The number of stools per week was higher after 4 weeks (2.46 ± 0.71 vs 5.29 ± 1.68, P<.001), as well as the stool form score (2.47 ± 1.24 vs 4.5 ± 0.91, P<.001). No statistical differences were obtained between urine sodium and urine osmolality values at the beginning and 4WP. After 4WP the NIRA median values were normal in all patients [fat 4.45% (range (r) 3.6-7.09); nitrogen 0.78% (r 0.4-1); sugars 1.4% (r 0.47-2.35) and water 68% (r 59-74)]. Median breath hydrogen test was 7 ppm (r 2-18).

CONCLUSIONS

No adverse effects on biochemistry values or gastrointestinal disturbances were observed. PEG+E can be recommended for the treatment of functional constipation in children.

[Validation of the Spanish version of the Revised Cystic Fibrosis Quality of Life Questionnaire in adolescents and adults (CFQR 14+ Spain)]

BACKGROUND

The aim of this study was to assess the validity and reliability of the Spanish version of the revised disease-specific health related quality of life questionnaire for adolescents and adults with cystic fibrosis (CFQR 14+ Spain).

METHODS

A total of 43 cystic fibrosis (CF) patients completed the CFQR 14+ Spain. Forced expiratory volume in 1 second, in percentage of predicted - FEV(1) (%)-, number of respiratory exacerbations, 6-minute walk test, Bhalla score (based on computerized tomography of the chest), fat-free mass index, body mass index (BMI), faecal fat and St George's Respiratory Questionnaire were included as measurements of health status.

RESULTS

Ten out of the twelve scales had alpha coefficients above 0.70. Test-retest correlations (Spearman) ranged from 0.49 to 0.95 and they were significant in all scales. Intraclass correlations ranged from 0.47 to 0.95 (ten out of the twelve scales were >0.70) forty out of the fifty ítems have correlations between items and scale above 0.70. All the CFQR+14 scales, except the digestive symptoms scale, discriminated significantly between patients with mild, moderate and severe disease (according to FEV(1) (%)). Other respiratory parameters also discriminated significantly between patients with mild-moderate and severe disease. Only some scales discriminated significantly between nourished and malnourished patients. All of the scales met standards for floor effects (<15% of the responders with the lowest score) but not for ceiling effects (only five out of the twelve).

CONCLUSION

The Spanish CFQR14+ (Spain) is a reliable and valid instrument for measuring the health-related quality of life in Spanish adolescents and adults with CF, though with the exception of a few of its subscales.

Lack of correlation between fecal elastase-1 levels and fecal nitrogen excretion in preterm infants

We measured fecal elastase-1 (FE1) levels in 34 preterm newborns (15 small-for-gestational-age and 19 appropriate-for-gestational-age) during the first 2 months of life and evaluated whether they were correlated with nitrogen loss in stools. FE1 increased over time, and values were similar in both groups of newborns. Fecal nitrogen was significantly higher in small-for-gestational-age infants. There was no correlation between FE1 levels and fecal nitrogen excretion. Pancreatic proteolytic function was efficient at an early stage in enterally fed preterm newborns. Despite the similar FE1 values, fecal nitrogen loss was significantly higher in small-for-gestational-age preterm infants than in appropriate-for-gestational-age preterm infants.

[Analysis of energy expenditure in adults with cystic fibrosis: comparison of indirect calorimetry and prediction equations]

OBJECTIVE

Undernutrition, which implies an imbalance between energy intake and energy requirements, is common in patients with cystic fibrosis. The aim of this study was to compare resting energy expenditure determined by indirect calorimetry with that obtained with commonly used predictive equations in adults with cystic fibrosis and to assess the influence of clinical variables on the values obtained.

PATIENTS AND METHODS

We studied 21 patients with clinically stable cystic fibrosis, obtaining data on anthropometric variables, hand grip dynamometry, electrical bioimpedance, and resting energy expenditure by indirect calorimetry. We used the intraclass correlation coefficient (ICC) and the Bland-Altman method to assess agreement between the values obtained for resting energy expenditure measured by indirect calorimetry and those obtained with the World Health Organization (WHO) and Harris-Benedict prediction equations.

RESULTS

The prediction equations underestimated resting energy expenditure in more than 90% of cases. The agreement between the value obtained by indirect calorimetry and that calculated with the prediction equations was poor (ICC for comparisons with the WHO and Harris-Benedict equations, 0.47 and 0.41, respectively). Bland-Altman analysis revealed a variable bias between the results of indirect calorimetry and those obtained with prediction equations, irrespective of the resting energy expenditure. The difference between the values measured by indirect calorimetry and those obtained with the WHO equation was significantly larger in patients homozygous for the DeltaF508 mutation and in those with exocrine pancreatic insufficiency.

CONCLUSIONS

The WHO and Harris-Benedict prediction equations underestimate resting energy expenditure in adults with cystic fibrosis. There is poor agreement between the values for resting energy expenditure determined by indirect calorimetry and those estimated with prediction equations. Underestimation was greater in patients with exocrine pancreatic insufficiency and patients who were homozygous for DeltaF508.

Serum phospholipid fatty acid profile and dietary intake in an adult Mediterranean population with cystic fibrosis

The relative importance of the usual diet in serum phospholipids in subjects with cystic fibrosis (CF) has been poorly studied. To compare the fatty acid profile in serum phospholipids from adult CF subjects with that of healthy subjects, and determine the role of the normal diet in this profile, we studied thirty-seven adult CF subjects with stable pulmonary disease and thirty-seven healthy controls matched for age, sex and nutritional status. A dietary questionnaire was obtained, anthropometric data were recorded, and the fatty acid profile measured by GLC. Compared with the controls, the percentages of myristic, palmitoleic and stearic acids and total MUFA were significantly higher in the CF group, and DHA, linoleic acid, total PUFA and n−6 fatty acids were significantly lower in the CF group. The CF subjects with worse pulmonary function and with pancreatic insufficiency had significantly lower levels of linoleic and n−6 fatty acids. The total energy intake was significantly higher in the CF subjects, although the energy distribution in the CF subjects and the controls was not different for the carbohydrates, lipids and proteins. No differences were detected in fat intake for MUFA (51 (sd 4) v. 52 (sd 4) %) or saturated fatty acids (33·5 (sd 5) v. 31·2 (sd 3·8) %), but the PUFA were slightly lower in the CF subjects (15·4 (sd 4·5) v. 17·4 (sd 4·2) %; P=0·02). The usual dietary intake of fatty acids by adult CF subjects does not appear to explain the difference in the fatty acid profile compared with controls. This suggests an abnormal fatty acid metabolism in CF subjects.

Comparison of near infrared reflectance analysis of fecal fat, nitrogen and water with conventional methods, and fecal energy content

OBJECTIVES

To evaluate Near-Infrared Analysis (NIRA) method for determining fecal fat, water and nitrogen.

DESIGN AND METHODS

The results of fecal fat, water and nitrogen by NIRA were compared with results of van de Kamer and Acid Steatocrit (AS), Dumas and vacuum drying methods for fat, nitrogen and water respectively. Results of fat determining methods were also compared with total fecal energy as obtained by bomb calorimeter.

RESULTS

NIRA results correlated significantly (p < 0.001) with standard methods for nitrogen (r = 0.79), fat (r = 0.84 and r = 0.88 for van de Kamer and AS respectively) and water (r = 0.91). The limits of agreement for nitrogen and fat results were too wide for the methods to be used interchangeably. The fecal fat results correlated significantly (p < 0.001) with fecal energy results.

CONCLUSION

NIRA may be valuable for monitoring malabsorption but the diagnostic value remains to be determined.

Antiendomysial antibody detection in fecal supernatants: in vivo proof that small bowel mucosa is the site of antiendomysial antibody production

OBJECTIVES

Serum antiendomysial antibodies (EMAs), highly sensitive and specific serological markers of celiac disease (CD), are detectable in culture media of biopsy samples from CD patients. This finding can be considered an in vitro evidence that intestinal mucosa is a site of EMA production. To confirm this finding, we investigated the presence of EMAs and of anti-tissue transglutaminase (anti-tTG), recently identified as the autoantigen of the EMA, in fecal supernatants of CD patients.

METHODS

Twenty-one newly diagnosed CD patients, 10 treated CD patients on a gluten-free diet, and 14 control disease patients on a gluten-containing diet were enrolled. Twenty-four-hour stool collections and fecal supernatants were obtained from all patients in the study. Biopsy cultures were also performed. IgA EMAs were detected in sera, culture media, and fecal supernatants. IgA, IgG, IgM, and IgE anti-gliadin antibodies (AGAs) and IgA anti-tTG antibodies were measured in fecal supernatants. The weights, water content, and pHs of the 24-h stool collections were also measured.

RESULTS

In all untreated CD patients EMAs were detectable in sera, culture media, and fecal supernatants. In treated CD patients, EMAs were detected only in culture media after in vitro gliadin challenge. No EMAs were detected in controls. Anti-tTG levels were higher in untreated CD patients than in treated CD patients and controls. IgA AGA levels were higher in untreated CD patients than in treated CD and control patients, whereas IgM AGAs were higher in both untreated and treated CD patients than in controls. No statistically significant differences were observed for IgG and IgE AGAs among the above-mentioned populations. Fecal weights, water content, and pHs were higher in untreated CD than in control patients.

CONCLUSIONS

The presence of EMAs in fecal supernatants represents the in vivo proof that intestinal mucosa is a site of EMA production. Furthermore, EMA detection in the stools could be a simple and useful additional tool to clarify diagnosis in the patchy conditions of CD.

Water, fat, nitrogen, and sugar content in feces: reference intervals in children

Malabsorption-maldigestion syndromes are commonly found in several gastrointestinal diseases. Quantitative measures of fecal nutrients are important tools for the detection and diagnosis of these syndromes. Adequate food intake is important in the nutrition of children, especially during the first year of life. We have analyzed 180 stools of healthy children, divided into four age groups, to obtain the reference intervals of the major nutrients such as water, fat, nitrogen, sugar, and starch. Quantification of the nutrients was done by means of a near-infrared analyzer (Fenir 8820). Results show that this instrument exhibits a low coefficient of variation for all the nutrients except for starch. Fecal water, fat, nitrogen, and sugar concentrations ranged from 68.7 to 96.1 g/100 g, 0 to 14.5 g/100 g, 1.3 to 2.3 g/100 g, and 0.7 to 3.8 g/100 g, respectively. The results for the starch analyses were not acceptable because of instrument limitations. Near-infrared reflectance spectroscopy appears to be an alternative to standard chemical methods.

Determination of fecal fat concentration by near infrared spectrometry for the screening of pancreatic steatorrhea

CONCLUSIONS

Near infrared reflectance analysis (NIRA) is a useful test for diagnosing fat malabsorption. Three-day stool collection and determination of fecal fat output are recommended. The measurement of fat concentration on spot samples may be of some use only in screening malabsorption of pancreatic origin; moreover, it does not discriminate between steatorrhea resulting from pancreatic insufficiency and that caused by gastrointestinal disorders.

BACKGROUND

NIRA has been proposed as an accurate method for the determination of fecal fat excretion. The aim of this study was to ascertain whether utilization of this technique to measure fat concentration in spot samples of feces is useful in screening for malabsorption.

METHODS

Twenty-five patients with chronic pancreatic disease and 95 with other digestive disorders were studied. In all patients, fecal fat assay with NIRA was performed on three different samples from each daily stool collection for 3 d. In 14 patients with pancreatic disease and 21 with gastrointestinal disorders, a colorimetric assay for fecal fat was performed for comparison.

RESULTS

When mean 3-d or daily fat fecal output were considered, a strict linear relationship was found between NIRA and the colorimetric method (r = 0.97 and 0.94, respectively). Using fat concentration, the two tests correlated less well (r= 0.74). Fat concentration was significantly higher in pancreatic than in nonpancreatic steatorrhea, even though values overlapped widely, and thus discrimination was not possible. The diagnostic efficiency of fat concentration for pancreatic and nonpancreatic steatorrhea was 72 and 61%, respectively.

Angiotensin-converting enzyme activity in stools of healthy subjects and patients with celiac disease

Angiotensin-converting enzyme (ACE) is a dipeptidylcarboxypeptidase that occurs in three types of cells: endothelial, epithelial, and neuroepithelial. ACE activity is present in plasma, urine, and vascular endothelium. High levels of ACE are found in the brush border of human small bowel. The aim of this study was to evaluate ACE activity in human stools and to find a correlation with the intestinal loss of epithelial cells. Fifteen healthy subjects (HS) (8 males, 7 females; age range 6-56 years), 20 patients with celiac disease (CD) (11 males, 9 females; age range 15-53 years), and 18 patients with CD in remission after a gluten-free diet (CD-GFD) (8 males, 10 females; age range 14-54 years) were enrolled in the study. The fecal ACE activity was measured in all groups. Fecal samples were kept at -20 degrees C for a subsequent test. In HS, fecal ACE activity was 21.03 +/- 16.17 nmol/min/100 g (mean +/- SD). In patients with CD with subtotal mucosa atrophy, ACE activity was significantly higher (113 +/- 88.94) than in HS and CD on GFD (36.65 +/- 23.9). We have demonstrated ACE activity in human stools. ACE activity in stools seems to derive from the microvilli of the intestinal mucosa, thus suggesting the potential usefulness of ACE determination as an index of enterocyte damage.