Hydroethanolic Extract of Urtica dioica L. (Stinging Nettle) Leaves as Disaccharidase Inhibitor and Glucose Transport in Caco-2 Hinderer.

Herbal treatment for diabetes mellitus is widely used. The pharmacological activity is thought to be due to the phenolic compounds found in the plant leaves. The present study aims to investigate the phytochemical composition of Urtica dioica (UD) hydroethanolic extract and to screen its antidiabetic activity by disaccharidase hindering and glucose transport in Caco-2 cells. The results have shown that a total of 13 phenolic compounds in this work, viz. caffeic and coumaric acid esters (1, 2, 4-7, 10), ferulic derivative (3), and flavonoid glycosides (8, 9, 11-13), were identified using HPLC-DAD-ESI/MS2. The most abundant phenolic compounds were 8 (rutin) followed by 6 (caffeoylquinic acid III). Less predominant compounds were 4 (caffeoylquinic acid II) and 11 (kaempferol-O-rutinoside). The UD hydroethanolic extract showed 56%, 45%, and 28% (1.0 mg/mL) inhibition level for maltase, sucrase, and lactase, respectively. On the other hand, glucose transport was 1.48 times less at 1.0 mg/mL UD extract compared with the control containing no UD extract. The results confirmed that U. dioica is a potential antidiabetic herb having both anti-disaccharidase and glucose transport inhibitory properties, which explained the use of UD in traditional medicine.

Routine disaccharidase testing: are we there yet?

PURPOSE OF REVIEW: Disaccharidase testing, as applied to the evaluation of gastrointestinal disturbances is available but it is not routinely considered in the diagnostic work-up. The purpose of this review was to determine if disaccharidase testing is clinically useful and to consider how the results could alter patient management. RECENT FINDINGS: Indicate that carbohydrate maldigestion could contribute functional bowel disorders and negatively impact the fecal microbiome. Diagnostic techniques include enzyme activity assays performed on random endoscopically obtained small intestinal biopsies, immunohistochemistry, stable isotope tracer and nonenriched substrate load breath testing, and genetic testing for mutations. More than 40 sucrase--isomaltase gene variants coding for defective or reduced enzymatic activity have been reported and deficiency conditions are more common than previously thought. SUMMARY: The rationale for disaccharidase activity testing relates to a need to fully assess unexplained recurrent abdominal discomfort and associated symptoms. All disaccharidases share the same basic mechanism of mucosal expression and deficiency has far reaching consequences. Testing for disaccharidase expression appears to have an important role in symptom evaluation, but there are accuracy and logistical issues that should be considered. It is likely that specific recommendations for patient management, dietary modification, and enzyme supplementation would come from better testing methods.

Clinical Characteristics of Disaccharidase Deficiencies Among Children Undergoing Upper Endoscopy.

OBJECTIVES: The epidemiology and clinical significance of disaccharidase deficiencies have not been thoroughly characterized. Recent work suggests at least genetic sucrase-isomaltase deficiency is more prevalent than previously believed. Because lactase deficiency (LD) is well described, the present study focuses on the clinical characteristics of children with disaccharidase deficiencies determined by esophagogastroduodenoscopy. METHODS: Endoscopic records were reviewed from patients undergoing esophagogastroduodenoscopies with biopsies assayed for disaccharidase activity performed by 13 pediatric gastroenterologists during 5 years (2010-2014). Presenting symptoms, clinical and histological diagnosis, treatment, disaccharidase results, and demographic variables were obtained from medical and endoscopic records of those with maltase and sucrase deficiency (SD). RESULTS: Among 963 patients undergoing intestinal disaccharidase testing, 73 (7.6%) had SD on biopsy (enzyme activity <25 µmol ·â€Šmin ·â€Šg). Thirty-four (34/73; 47%) had normal duodenal histology and are the focus of this report. Four patients had SD without LD. Pan-disaccharidase deficiency was observed in 24 patients when maltase and palatinase assays were obtained (n = 646), and 11 had SD + LD when just those 2 enzymes were analyzed (n = 317). Those with SD without LD were younger 4.6 ±â€Š6.1 versus 14.1 ±â€Š3.6 years and uniformly presented with diarrhea. Patients with pan-disaccharidase deficiency or SD + LD primarily reported abdominal pain (33/35; 94%), diarrhea (16/35; 46%), nausea (14/35; 40%); and poor weight gain/weight loss (10/35; 29%); constipation, flatulence, and bloating were also noted. Maltase deficiency is less common (8/963; 0.8%), presenting with similar symptoms. CONCLUSIONS: Genetic sucrase-isomaltase deficiency often occurs together with lactase or pan-disaccharide deficiency. Disaccharidase deficiency should be considered a potential cause of abdominal pain and/or diarrhea in children and adolescents.

Does a diet low in FODMAPs reduce symptoms associated with functional gastrointestinal disorders? A comprehensive systematic review and meta-analysis.

BACKGROUND: Functional gastrointestinal symptoms such as abdominal pain, bloating, distension, constipation, diarrhea and flatulence have been noted in patients with irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD). The diversity of symptoms has meant that finding an effective treatment has been challenging with most treatments alleviating only the primary symptom. A novel treatment option for IBS and IBD currently generating much excitement is the low fermentable, oligo-, di-, mono-saccharides and polyol (FODMAP) diet. The aim of this meta-analysis was to determine the evidence of the efficacy of such a diet in the treatment of functional gastrointestinal symptoms. METHODS: Electronic databases were searched through to March 2015 to identify relevant studies. Pooled odds ratios (ORs) and 95 % confidence intervals were calculated for the effect of a low FODMAP diet on the reduction in IBS [Symptoms Severity Score (SSS)] score and increase in IBS quality of life (QOL) score for both randomized clinical trials (RCTs) and non-randomized interventions using a random-effects model. RESULTS: Six RCTs and 16 non-randomized interventions were included in the analysis. There was a significant decrease in IBS SSS scores for those individuals on a low FODMAP diet in both the RCTs (OR 0.44, 95 % CI 0.25-0.76; I (2) = 35.52, p = 0.00) and non-randomized interventions (OR 0.03, 95 % CI 0.01-0.2; I (2) = 69.1, p = 0.02). In addition, there was a significant improvement in the IBS-QOL score for RCTs (OR 1.84, 95 % CI 1.12-3.03; I (2) = 0.00, p = 0.39) and for non-randomized interventions (OR 3.18, 95 % CI 1.60-6.31; I (2) = 0.00, p = 0.89). Further, following a low FODMAP diet was found to significantly reduce symptom severity for abdominal pain (OR 1.81, 95 % CI 1.13-2.88; I (2) = 0.00, p = 0.56), bloating (OR 1.75, 95 % CI 1.07-2.87; I (2) = 0.00, p = 0.45) and overall symptoms (OR 1.81, 95 % CI 1.11-2.95; I (2) = 0.00, p = 0.4) in the RCTs. In the non-randomized interventions similar findings were observed. CONCLUSION: The present meta-analysis supports the efficacy of a low FODMAP diet in the treatment of functional gastrointestinal symptoms. Further research should ensure studies include dietary adherence, and more studies looking at greater number of patients and long-term adherence to a low FODMAP diet need to be conducted.

A novel type of matrix for surface-assisted laser desorption-ionization mass spectrometric detection of biomolecules using metal-organic frameworks.

A 3D metal-organic framework (MOF) nanomaterial as matrix for surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) and tandem mass spectrometry (MS/MS) was developed for the analysis of complex biomolecules. Unlike other nanoparticle matrices, this MOF nanomaterial does not need chemical modification prior to use. An exceptional signal reproducibility as well as very low background interferences in analyzing mono-/di-saccharides, peptides and complex starch digests demonstrate its high potential for biomolecule assays, especially for small molecules.

Maternal protein restriction affects gene expression and enzyme activity of intestinal disaccharidases in adult rat offspring.

This study investigated the consequences of intrauterine protein restriction on the gastrointestinal tract and particularly on the gene expression and activity of intestinal disaccharidases in the adult offspring. Wistar rat dams were fed isocaloric diets containing 6% protein (restricted, n = 8) or 17% protein (control, n = 8) throughout gestation. Male offspring (n = 5-8 in each group) were evaluated at 3 or 16 weeks of age. Maternal protein restriction during pregnancy produced offspring with growth restriction from birth (5.7 ± 0.1 vs 6.3 ± 0.1 g; mean ± SE) to weaning (42.4 ± 1.3 vs 49.1 ± 1.6 g), although at 16 weeks of age their body weight was similar to control (421.7 ± 8.9 and 428.5 ± 8.5 g). Maternal protein restriction also increased lactase activity in the proximal (0.23 ± 0.02 vs 0.15 ± 0.02), medial (0.30 ± 0.06 vs 0.14 ± 0.01) and distal (0.43 ± 0.07 vs 0.07 ± 0.02 U·g-1·min-1) small intestine, and mRNA lactase abundance in the proximal intestine (7.96 ± 1.11 vs 2.38 ± 0.47 relative units) of 3-week-old offspring rats. In addition, maternal protein restriction increased sucrase activity (1.20 ± 0.02 vs 0.91 ± 0.02 U·g-1·min-1) and sucrase mRNA abundance (4.48 ± 0.51 vs 1.95 ± 0.17 relative units) in the duodenum of 16-week-old rats. In conclusion, the present study shows for the first time that intrauterine protein restriction affects gene expression of intestinal enzymes in offspring.

Maternal protein restriction affects gene expression and enzyme activity of intestinal disaccharidases in adult rat offspring

This study investigated the consequences of intrauterine protein restriction on the gastrointestinal tract and particularly on the gene expression and activity of intestinal disaccharidases in the adult offspring. Wistar rat dams were fed isocaloric diets containing 6% protein (restricted, n = 8) or 17% protein (control, n = 8) throughout gestation. Male offspring (n = 5-8 in each group) were evaluated at 3 or 16 weeks of age. Maternal protein restriction during pregnancy produced offspring with growth restriction from birth (5.7 ± 0.1 vs 6.3 ± 0.1 g; mean ± SE) to weaning (42.4 ± 1.3 vs 49.1 ± 1.6 g), although at 16 weeks of age their body weight was similar to control (421.7 ± 8.9 and 428.5 ± 8.5 g). Maternal protein restriction also increased lactase activity in the proximal (0.23 ± 0.02 vs 0.15 ± 0.02), medial (0.30 ± 0.06 vs 0.14 ± 0.01) and distal (0.43 ± 0.07 vs 0.07 ± 0.02 U·g-1·min-1) small intestine, and mRNA lactase abundance in the proximal intestine (7.96 ± 1.11 vs 2.38 ± 0.47 relative units) of 3-week-old offspring rats. In addition, maternal protein restriction increased sucrase activity (1.20 ± 0.02 vs 0.91 ± 0.02 U·g-1·min-1) and sucrase mRNA abundance (4.48 ± 0.51 vs 1.95 ± 0.17 relative units) in the duodenum of 16-week-old rats. In conclusion, the present study shows for the first time that intrauterine protein restriction affects gene expression of intestinal enzymes in offspring.

Rapid and sensitive determination of carbohydrates in foods using high temperature liquid chromatography with evaporative light scattering detection.

In the present work, an evaporative light scattering detector was used as a high-temperature liquid chromatography detector for the determination of carbohydrates. The compounds studied were glucose, fructose, galactose, sucrose, maltose, and lactose. The effect of column temperature on the retention times and detectability of these compounds was investigated. Column heating temperatures ranged from 25 to 175°C. The optimum temperature in terms of peak resolution and detectability with pure water as mobile phase and a liquid flow rate of 1 mL/min was 150°C as it allowed the separation of glucose and the three disaccharides here considered in less than 3 min. These conditions were employed for lactose determination in milk samples. Limits of quantification were between 2 and 4.7 mg/L. On the other hand, a temperature gradient was developed for the simultaneous determination of glucose, fructose, and sucrose in orange juices, due to coelution of monosaccharides at temperatures higher than 70°C, being limits of quantifications between 8.5 and 12 mg/L. The proposed hyphenation was successfully applied to different types of milk and different varieties of oranges and mandarins. Recoveries for spiked samples were close to 100% for all the studied analytes.

Disaccharidase deficiency in pediatric patients with celiac disease and intact villi.

BACKGROUND AND AIMS: The "gold standard" for the diagnosis of celiac disease (CD) is the small intestinal biopsy. A significant number of biopsies are inadequate for interpretation. Furthermore, the labeling of a biopsy as a Marsh I or II is somewhat subjective and may vary with the experience of the pathologist. Our hypothesis is that patients with intact villi undergoing biopsies frequently have associated disaccharidase deficiencies (DSD). METHODS: We reviewed 220 charts of pediatric patients with CD and selected those with a duodenal biopsy Marsh score of I/II. The disaccharidase (DS) levels of these patients were compared with a randomly selected, age-matched control group. DSD is defined as levels below the lower limits of normal. RESULTS: Lactase (mean lactase = 18.8 in the control group vs. 4.2 in the diseased group, p = 0.004); sucrase (mean sucrase = 46.4 in the control group vs. 21.4 in the diseased group, p = 0.001); maltase (mean maltase = 138 in the control group vs. 52.5 in the diseased group, p = 0.001); palatinase (mean palatinase = 9.6 in the control group vs. 3.3 in the diseased group, p < 0.001). CONCLUSION: There is a profound deficiency of DS levels in pediatric patients with CD who have intact villi.

High-throughput tissue homogenization method and tissue-based quality control materials for a clinical assay of the intestinal disaccharidases.

BACKGROUND: The definitive biochemical test for the diagnosis of disaccharidase deficiencies is the determination of enzyme activities in small bowel mucosa. Traditional methods of tissue homogenization are limited by low throughput. Lack of tissue-based quality control materials is a limitation for clinical laboratories that perform tests of the intestinal disaccharidases. The objectives of this study were to develop a method for determining disaccharidase activities using a high-throughput homogenization method and to create matrix-appropriate quality control materials. METHODS: Intestinal mucosa was homogenized using three different methods. Activities of lactase, maltase, palatinase, and sucrase were determined by measuring glucose liberated from a hydrolysis reaction with disaccharide substrates and normalized to total protein concentration. Tissue-based quality control materials were developed from pig intestine and pooled clinical specimens. RESULTS: A high-throughput homogenization method processed 24 specimens in 2 min compared to 1 specimen per 2 min for traditional methods. There were no significant differences (p>0.90) in enzyme activities as a function of the homogenization method used. 92 determinations of enzyme activities from 23 clinical specimens showed acceptable agreement (y=1.13x-6.6) and were highly correlated (r=0.95) as compared to results obtained by an external laboratory. Enzyme activities were variably inactivated by temperatures > or = 60 degrees C. Pig intestinal mucosa produced non-deficient enzyme activities while deficient activities were produced by combining equal volumes of unheated and heat-inactivated homogenates pooled from clinical specimens. CONCLUSIONS: A high-throughput method of tissue homogenization was more efficient than traditional methods and did not affect enzyme activities. Matrix-appropriate quality control materials can be created from pig intestine and pooled human homogenates.

Structural and functional changes of sulfated glycosaminoglycans in Xenopus laevis during embryogenesis.

Xenopus laevis is an excellent animal for analyzing early vertebrate development. Various effects of glycosaminoglycans (GAGs) on growth factor-related cellular events during embryogenesis have been demonstrated in Xenopus. To elucidate the relationship between alterations in fine structure and changes in the specificity of growth factor binding during Xenopus development, heparan sulfate (HS) and chondroitin/dermatan sulfate (CS/DS) chains were isolated at four different embryonic stages and their structure and growth factor-binding capacities were compared. The total amounts of both HS and CS/DS chains decreased from the pre-midblastula transition to the gastrula stage, but increased exponentially during the following developmental stages. The length of HS chains was not significantly affected by development, whereas that of CS/DS chains increased with development. The disaccharide composition of GAGs in embryos also changed during development. The degree of sulfation of the HS chains gradually decreased with development. The predominant sulfation position in the CS/DS chains shifted from C4 to C6 of GalNAc during embryogenesis. Growth factor-binding experiments using a BIAcore system demonstrated that GAGs bound growth factors including fibroblast growth factors-1 and -2, midkine, and pleiotrophin, with comparable affinities. These affinities significantly varied during development, although the correlation between the structural alterations of GAGs and the change in the ability to bind growth factors remains to be clarified. The expression of saccharide sequences, which specifically interact with a growth factor, might be regulated during development.

Effects of crude red kidney bean lectin (phytohemagglutinin) exposure on performance, health, feeding behavior, and gut maturation of pigs at weaning.

The aim of this study was to obtain information that could help to ease the weaning transition in commercial pig production. Before weaning, phytohemagglutinin (PHA) in the form of a crude preparation of red kidney bean lectin was fed by gavage to 24 crossbred [(Swedish Landrace x Yorkshire) x Hampshire] piglets, whereas 24 control piglets were fed alpha-lactalbumin by gavage, to study the effect on growth, occurrence of postweaning diarrhea, feeding behavior, and some anatomical and physiological traits of the gastrointestinal tract. Within the litter, piglets were randomly assigned to PHA treatment or control and remained in the same pen from the beginning (PHA exposure at 7 d before weaning) until the end of the experiment (14 d post-weaning). Weaning took place at the age of 31 to 34 d. Pigs treated with PHA grew faster (P = 0.013) during the first week postweaning and tended to have lower total diarrhea scores (P = 0.10) than did control pigs. On d 5 after weaning, piglets treated with PHA spent more time eating (P = 0.028) than control pigs. No immunostimulating effect of PHA, measured by plasma immunoglobulin G, could be detected. An increase in the intestinal barrier properties before weaning, as a response to PHA treatment, was demonstrated in intestinal absorption studies using Na-fluorescein and BSA as gavage-fed markers. Less uptake (measured as plasma concentrations) of the marker molecule Na-fluorescein occurred during a 24-h study period, and numerically lower levels of BSA were observed compared with studies in control pigs of the same age. A total of 12 pigs (6 control, 6 PHA-treated) were euthanized on the day of weaning for analyses of gastrointestinal properties. The PHA-treated pigs tended to have a longer total small intestinal length (P = 0.063) than that of the control pigs. The enzyme profile of the jejunal epithelium responded to PHA exposure with a decrease in lactase activity and an increase in maltase and sucrase activities, which is similar to changes normally observed after weaning. No differences were found in the size of the pancreas or in its contents of trypsin and amylase. In conclusion, exposing piglets to crude, red kidney bean lectin for 3 d during the week before weaning led to changes in performance and small intestinal functional properties that would be expected to contribute to a more successful weaning.

Phenotypic flexibility in the intestinal enzymes of the African clawed frog Xenopus laevis.

The intestinal plasticity of digestive enzymes of amphibian species is poorly known. The goal of this study was to characterize digestive enzyme profiles along the small intestine of adult frogs, Xenopus laevis, in response to an experimental diet. We acclimated adult X. laevis for 30 days either to carbohydrate-rich or protein-rich diets, and determined the morphology and digestive enzymes of the small intestine. We found a significant difference of aminopeptidase-N activity between carbohydrate-rich and protein-rich acclimated animals. We also found a little variation in the expression of maltase activity, which contrast with the proposed hypothesis about the existence of digestive tradeoff in vertebrates. This finding supports the adaptive modulation hypothesis and suggests that caution is called for when analyzing physiological data regarding assumed discrete trophic category of species.

Comparison of duodenal and jejunal disaccharidase levels in patients with non ulcer dyspepsia.

AIMS: This study was conducted to compare the duodenal and jejunal disaccharidase levels in the same individual with duodenal ulcer or non ulcer dyspepsia. METHODS: Thirty seven patients (duodenal ulcer--11, non-ulcer dyspepsia--26) were included in the study. Endoscopic biopsy samples were obtained from jejunum and duodenum using pediatric colonofibroscope. RESULTS: Levels of jejunal disaccharidases were significantly higher than the duodenal disaccharidases. CONCLUSIONS: An estimate of jejunal disaccharidases can be had by multiplication of duodenal disaccharidased by a factor 1.48 for lactase, 1.50 for sucrase and 1.56 for maltase.

Chemotherapy for cancer causes apoptosis that precedes hypoplasia in crypts of the small intestine in humans.

BACKGROUND AND AIMS: The mechanism of gastrointestinal damage (mucositis) induced by cancer chemotherapy remains uncertain. The aims of this study were to define the time course and mechanism of small intestinal damage following chemotherapy in humans. METHODS: Patients receiving chemotherapy underwent upper gastrointestinal endoscopy (a maximum of two per patient) with duodenal biopsy prior to chemotherapy and again at 1, 3, 5, and 16 days after chemotherapy. Tissue was taken for morphometry, disaccharidase assays, electron microscopy, and for assessment of apoptosis using the Tdt mediated dUTP-biotin nick end labelling (TUNEL) method. Villus area, crypt length, and mitotic index were measured by a microdissection technique. RESULTS: Apoptosis increased sevenfold in intestinal crypts at one day, and villus area, crypt length, mitotic count per crypt, and enterocyte height decreased at three days after chemotherapy. Disaccharidase activities remained unchanged. Electron microscopy showed increased open tight junctions of enterocytes at day 3, consistent with more immature cells. All indices improved by 16 days. CONCLUSION: Small intestinal mucositis is associated with apoptosis in crypts that precedes hypoplastic villous atrophy and loss of enterocyte height.

Relation of the disaccharidases in the small intestine of the rat to the degree of experimentally induced iron-deficiency anemia

Hypolactasia associated with severe iron-deficiency anemia has been reported in several studies. The objective of the present study was to determine whether hypolactasia is associated with the degree and duration of iron-deficiency anemia. Newly weaned male Wistar rats were divided into a control group receiving a diet supplemented with iron (C) and an experimental group (E) receiving a diet not supplemented with iron (iron-deficiency diet). The animals were studied on the 3rd, 5th, 7th, 14th, 21st, 28th and 35th days of the experiment, when overall and iron nutritional status and disaccharidase activity in the small intestine were determined by the Dahlqvist method. A reduction in weight occurred in the anemic animals starting on the 5th day of the study. Anemia was present in the experimental animals, with a progressive worsening up to the 14th day (hemoglobin: C = 13.27 and E = 5.37) and stabilizing thereafter. Saccharase and maltase activities did not differ significantly between groups, whereas lactase showed a significant reduction in total (TA) and specific activity (SA) in the anemic animals starting on the 21st day of the study. Median lactase TA for the C and E groups was 2.27 and 1.25 U on the 21st day, 2.87 and 1.88 U on the 28th day, and 4.20 and 1.59 U on the 35th day, respectively. Median lactase SA was 0.31 and 0.20 U/g wet weight on the 21st day, 0.39 and 0.24 U/g wet weight on the 28th day, and 0.42 and 0.23 U/g wet weight on the 35th day, respectively. These findings suggest a relationship between the enzymatic alterations observed and both the degree and duration of the anemic process. Analysis of other studies on intestinal disaccharidases in anemia suggests that the mechanism of these changes may be functional, i.e., that the enterocytes may suffer a reduction in their ability to synthesize these enzymes.

Relation of the disaccharidases in the small intestine of the rat to the degree of experimentally induced iron-deficiency anemia.

Hypolactasia associated with severe iron-deficiency anemia has been reported in several studies. The objective of the present study was to determine whether hypolactasia is associated with the degree and duration of iron-deficiency anemia. Newly weaned male Wistar rats were divided into a control group receiving a diet supplemented with iron (C) and an experimental group (E) receiving a diet not supplemented with iron (iron-deficiency diet). The animals were studied on the 3rd, 5th, 7th, 14th, 21st, 28th and 35th days of the experiment, when overall and iron nutritional status and disaccharidase activity in the small intestine were determined by the Dahlqvist method. A reduction in weight occurred in the anemic animals starting on the 5th day of the study. Anemia was present in the experimental animals, with a progressive worsening up to the 14th day (hemoglobin: C = 13.27 and E = 5.37) and stabilizing thereafter. Saccharase and maltase activities did not differ significantly between groups, whereas lactase showed a significant reduction in total (TA) and specific activity (SA) in the anemic animals starting on the 21st day of the study. Median lactase TA for the C and E groups was 2.27 and 1.25 U on the 21st day, 2.87 and 1. 88 U on the 28th day, and 4.20 and 1.59 U on the 35th day, respectively. Median lactase SA was 0.31 and 0.20 U/g wet weight on the 21st day, 0.39 and 0.24 U/g wet weight on the 28th day, and 0.42 and 0.23 U/g wet weight on the 35th day, respectively. These findings suggest a relationship between the enzymatic alterations observed and both the degree and duration of the anemic process. Analysis of other studies on intestinal disaccharidases in anemia suggests that the mechanism of these changes may be functional, i.e., that the enterocytes may suffer a reduction in their ability to synthesize these enzymes.

Modification of disaccharidase activity measurement in rat bowel.

This study describes a modification of the existing disaccharidase assay in rat small bowel in which whole bowel, rather than mucosa, is utilized. In addition, the use of total vs. specific activity as a more accurate unit of measurement of disaccharidase activity is discussed.

Disaccharidase activities in children: normal values and comparison based on symptoms and histologic changes.

BACKGROUND: The relationship between symptoms, intestinal mucosal histology, and disaccharidase activities is not well defined. An analysis of disaccharidase activities was performed in children grouped by age, symptoms, and intestinal mucosal histology and normal values established. METHODS: Disaccharidase activities and histology of 246 endoscopically obtained duodenal biopsies in 232 patients (121 girls; age range, 0.08-17 years; mean, 5.9 years) in a 3-year period were reviewed. Patients were divided into two groups based on absence (group 1; n = 142) or presence (group 2; n = 90) of diarrhea and were subdivided by age into, less than 24 months of age and 24 months of age or more. Histologic changes within groups were classified as (A) normal, (B) mild, or (C) moderate to severe based on villus height abnormalities. A questionnaire was sent to 34 patients with hypolactasia to assess the efficacy of lactose avoidance and/or lactase supplementation. RESULTS: All group 1 patients had normal findings in analysis of mucosal specimens, and their disaccharidase activities showed normal values because they had no diarrhea. The geometric means (95% confidence interval) in children aged less than 24 months are (in micromoles of substrate hydrolyzed per minute at 37 degrees C per gram protein) (units [U]) lactase, 36.7 (13.4-100.4); maltase, 178.5 (88.9-356.3); palatinase, 12.7 (3.8-41.5); and sucrase 60.0 (24.0-148.1). In children 24 months of age or more, the values are 23.2 (3.9-108.1), 167.6 (78.8-355.9), 12.7 (4.9-32.9), and 51.0 (20.5-126.0), respectively. Only lactase activity decreased with age (p < 0.05). No differences in disaccharidase activities were noted in patients with and without diarrhea if the mucosal histology was normal (group 1A vs. 2A). In patients with diarrhea, values were commensurate with the degree of mucosal injury, especially in the older group. Twenty-two of 27 patients (81%) who responded to the questionnaire had benefited from lactase supplementation and/or lactose avoidance. CONCLUSIONS: We have established normal values for disaccharidase activities in the pediatric population. Although the disaccharidase activities correlate more with degree of intestinal mucosal injury than with symptoms, their activities are difficult to predict accurately based on these criteria. If required, disaccharidase activities should be measured biochemically.