Miglustat-induced intestinal carbohydrate malabsorption is due to the inhibition of α-glucosidases, but not β-galactosidases

Miglustat is an oral medication that has approved indication for type I Gaucher disease and Niemann pick disease type C. Usually treatment with Miglustat is associated with occurrence of gastrointestinal side effects similar to carbohydrate maldigestion symptoms. Here, we studied the direct influence of Miglustat on the enzymatic function of the major disaccharidases of the intestinal epithelium. Our findings show that an immediate effect of Miglustat is its interference with carbohydrate digestion in the intestinal lumen via reversible inhibition of disaccharidases that cleave α-glycosidically linked carbohydrates. Higher non physiological concentrations of Miglustat can partly affect lactase activity. We further show that the inhibition of the disaccharidases function by Miglustat is mainly competitive and does not occur via alteration of the enzyme folding.

[Digestive enzyme functionality in pathology of the gastrointestinal tract with intestinal microbiocenosis disorders]

A change pattern in enzyme release function of digestive glands exerts the organism as a whole. Dysfunctions of hydrolysis and intestinal malabsorption (secondary malabsorption syndrome) are the first step towards nutrition and metabolism processes abnormality and that can play a role in genesis of pathological conditions. Recent researches arouse clinicians interest in determination of biofluid enzyme activity in different physiological and abnormal cases. Intestinal infections are followed by dysbacteriosis and obvious alterations in the hydrolase levels in the blood, urine and motions because of the changes of functional status of the liver, renal and intestinal barriers in relation to increted digestive enzymes. This causes an unfavorable course of recovery with the development of postinfectious digestion disorders as a result of previous acute diarrhea. Future researches are necessary to elaborate appropriate remodeling of developed pathosis with the help of enzymotherapy and probiotic diet.

Serum and intestinal dipeptidyl peptidase IV (DPP IV/CD26) activity in children with celiac disease

OBJECTIVE

Dipeptidyl peptidase IV (DPP IV/CD26) is involved in the degradation of proline-rich proteins such as gliadin and in modulation of the immune response. The aim of this study was to examine the possible causal connection between DPP IV enzyme activities and celiac disease (CD) in children.

PATIENTS AND METHODS

Intestinal mucosal biopsy specimens were obtained from 97 patients. The patients were divided into 3 groups: patients with active CD (n = 38), patients with malabsorption syndrome (MS) of other causes (n = 37), and control patients (n = 22). In addition, blood samples were collected from 48 patients with active CD and 50 control patients without gastrointestinal diseases. DPP IV enzyme activity was measured in the intestinal mucosal biopsy specimens and in the serum samples.

RESULTS

DPP IV activity in the small intestine correlated inversely with the grade of mucosal damage in the CD (r = -0.92, P < 0.001) and MS groups (r = -0.90, P < 0.001). Intestinal DPP IV activity was statistically significantly lower in the CD and MS groups than in the control group (P < 0.001). By contrast, serum DPP IV activity was not significantly different between the CD and control groups.

CONCLUSIONS

Our results suggest that the decrease in intestinal DPP IV activity is not specific to CD because it correlates with the level of mucosal damage in both patients with CD and those with MS. In addition, it seems that serum DPP IV activity cannot be used as a specific noninvasive diagnostic or prognostic marker of CD.

Novel mutations in the human sucrase-isomaltase gene (SI) that cause congenital carbohydrate malabsorption

Disaccharide intolerance I or congenital sucrase-isomaltase deficiency (CSID) is a disorder leading to maldigestion of disaccharides, which is autosomal recessively inherited. Here we analyzed the sucrase-isomaltase (SI) gene from 11 patients of Hungarian origin with congenital sucrase-isomaltase deficiency. Variants in the SI gene had previously been described in CSID patients, which cause amino acid exchanges that affect the transport, the processing, or the function of the SI protein. None of our patients had known mutations for CSID. Our analyses revealed 43 SI variants in total, 15 within exons and one at a splice site. Eight of the exonic mutations lead to amino acid exchanges, causing hypomorph or null alleles. One new variation affects a splice site, which is also predicted to result in a null allele. All potential pathological alterations were present on one allele only. In six out of the 11 patients the phenotype of CSID could be explained by compound heterozygosity.

Enteric-coated pancreatic enzyme with bicarbonate is equal to standard enteric-coated enzyme in treating malabsorption in cystic fibrosis

OBJECTIVES

To compare the efficacy of an enteric-coated buffered pancreatic enzyme (EC buffered PE) containing 1.5 mEq of bicarbonate per capsule with a conventional enteric-coated enzyme (EC-PE) capsule in cystic fibrosis patients with signs or symptoms of moderate to severe malabsorption.

METHODS

In a double-blind crossover study, subjects were randomly assigned to two consecutive, 2-week phases using an EC buffered PE product and conventional EC-PE product. Seventy-two hour stool collections from each phase were analyzed for energy, fat, and nitrogen content and expressed as percent of estimated intake.

RESULTS

Twenty-one patients with cystic fibrosis and pancreatic insufficiency (14 female, mean age 20.6 +/- 11.5 years, range 8.8-41.9) completed the study. There was no significant difference in percent malabsorption of energy (19.4% vs. 19.0%), fat (20.7% vs. 20.2%), or nitrogen (10.4% vs. 10.7%) between the EC buffered PE product and the conventional EC-PE product. However, patients taking the EC buffered PE product received less enzyme based on actual enzyme activity measured in vitro (3,468 +/- 1,434 U lipase/g fat vs. 3,978 +/- 1,474 U lipase/g fat, P < 0.02).

CONCLUSIONS

In the doses used, nutrient absorption of patients taking EC buffered PE preparation offers no advantage over a conventional EC-PE preparation.

Disaccharidase activities in Belgian children: reference intervals and comparison with non-Belgian Caucasian children

AIM

To establish reference values for disaccharidase activities in Belgian children and to compare enzyme activities with those of non-Belgian Caucasian children.

METHODS

Data from Belgian children who had undergone endoscopic jejunal biopsies (1994-2000) for suspected malabsorption were reviewed. The patients were divided into three groups based on histology: (A) normal (n = 201), (B) moderate changes (n = 58) and (C) (sub)total atrophy (n = 14). The 95% reference limits for disaccharidase activities (U/g protein) were calculated for group A after exclusion of patients with a positive hydrogen breath test, a history of lactose intolerance or coeliac disease (final population: n = 151, 0.1-12 y). Values were compared with those of 34 non-Belgian Caucasian children with normal histology (28 of Mediterranean origin).

RESULTS

The reference limits (90% confidence interval) were 86 (65-111)-423 (366-494) for maltase, 9 (6-12)-91 (78-122) for lactase and 24 (18-30)-155 (120-184) for sucrase. No gender-related differences in enzyme activities were found. Lactase levels showed a slight decrease with increasing age. Disaccharidase activities of children with histologically confirmed mucosal injury were significantly lower than those of children with normal histology: median values for groups A, B and C were 208, 181 and 96, respectively, for maltase, 40, 28 and 7, respectively, for lactase and 69, 54 and 25, respectively, for sucrase. Median disaccharidase activities in biopsies with normal histology were lower in non-Belgian children, the difference being only statistically significant for lactase, 33 versus 40.

CONCLUSION

The reference values for Belgian children are well in line with other reported values from Caucasian children. Although enzyme activities are lower in children with histologically confirmed mucosal damage, they do not allow differentiation between histology groups. Lower lactase values were found in non-Belgian children.

Disaccharidase activities in Belgian children: reference intervals and comparison with non-Belgian Caucasian children

AIM

To establish reference values for disaccharidase activities in Belgian children and to compare enzyme activities with those of non-Belgian Caucasian children.

METHODS

Data from Belgian children who had undergone endoscopic jejunal biopsies (1994-2000) for suspected malabsorption were reviewed. The patients were divided into three groups based on histology: (A) normal (n = 201), (B) moderate changes (n = 58) and (C) (sub)total atrophy (n = 14). The 95% reference limits for disaccharidase activities (U/g protein) were calculated for group A after exclusion of patients with a positive hydrogen breath test, a history of lactose intolerance or coeliac disease (final population: n = 151, 0.1-12 y). Values were compared with those of 34 non-Belgian Caucasian children with normal histology (28 of Mediterranean origin).

RESULTS

The reference limits (90% confidence interval) were 86 (65-111)-423 (366-494) for maltase, 9 (6-12)-91 (78-122) for lactase and 24 (18-30)-155 (120-184) for sucrase. No gender-related differences in enzyme activities were found. Lactase levels showed a slight decrease with increasing age. Disaccharidase activities of children with histologically confirmed mucosal injury were significantly lower than those of children with normal histology: median values for groups A, B and C were 208, 181 and 96, respectively, for maltase, 40, 28 and 7, respectively, for lactase and 69, 54 and 25, respectively, for sucrase. Median disaccharidase activities in biopsies with normal histology were lower in non-Belgian children, the difference being only statistically significant for lactase, 33 versus 40.

CONCLUSION

The reference values for Belgian children are well in line with other reported values from Caucasian children. Although enzyme activities are lower in children with histologically confirmed mucosal damage, they do not allow differentiation between histology groups. Lower lactase values were found in non-Belgian children.

Mutations in a Sar1 GTPase of COPII vesicles are associated with lipid absorption disorders

Dietary fat is an important source of nutrition. Here we identify eight mutations in SARA2 that are associated with three severe disorders of fat malabsorption. The Sar1 family of proteins initiates the intracellular transport of proteins in COPII (coat protein)-coated vesicles. Our data suggest that chylomicrons, which vastly exceed the size of typical COPII vesicles, are selectively recruited by the COPII machinery for transport through the secretory pathways of the cell.

Molecular genetics of 3beta-hydroxy-Delta5-C27-steroid oxidoreductase deficiency in 16 patients with loss of bile acid synthesis and liver disease

The 3beta-hydroxy-Delta(5)-C(27)-steroid oxidoreductase (C(27) 3beta-HSD) is a membrane-bound enzyme of the endoplasmic reticulum that catalyzes an early step in the synthesis of bile acids from cholesterol. Subjects with autosomal recessive mutations in the encoding gene, HSD3B7, on chromosome 16p11.2-12 fail to synthesize bile acids and develop a form of progressive liver disease characterized by cholestatic jaundice and malabsorption of lipids and lipid-soluble vitamins from the gastrointestinal tract. The gene encoding the human C(27) 3beta-HSD enzyme was isolated previously, and a 2-bp deletion in exon 6 of HSD3B7 was identified in a well characterized subject with this disorder. Here, we report a molecular analysis of 15 additional patients from 13 kindreds with C(27) 3beta-HSD deficiency. Twelve different mutations were identified in the HSD3B7 gene on chromosome 16p11.2-12. Ten mutations were studied in detail and shown to cause complete loss of enzyme activity and, in two cases, alterations in the size or amount of the transcribed mRNA. Mutations were inherited in homozygous form in 13 subjects from 10 families and compound heterozygous form in four subjects from three families. We conclude that a diverse spectrum of mutations in the HSD3B7 gene underlies this rare form of neonatal cholestasis.

Fecal elastase-1 is decreased in villous atrophy regardless of the underlying disease

BACKGROUND

Fecal elastase-1 (E1) is a sensitive and reliable test in the assessment of exocrine pancreatic function in cystic fibrosis (CF). In patients with celiac disease (CD), different E1 values have been reported. E1 levels in other malabsorption conditions are unknown. Therefore, the aim of the present study was to evaluate E1 concentrations in various malabsorption syndromes.

MATERIAL AND METHODS

The study was carried out in 54 patients, selected from patients referred with suspicion of CF, who had been diagnosed as celiac disease (CD; n = 16), secondary malabsorption syndrome (SMS, giardiasis- or cow milk-related enteropathy; n = 18) and food allergy (FA; n = 20). 70 age-matched healthy children (HC) and 131 cystic fibrosis (CF) patients served as control groups. In CD and SMS patients, a gluten-free diet was introduced. In addition, SMS patients were treated appropriately to underlying disease. In all subjects, E1 concentrations were measured. In CD and SMS patients, E1 concentrations were repeatedly measured after one year of the treatment.

RESULTS

With a cut-off level of 200 microg g-1, abnormal E1 concentrations were found in 87.2% of the CF group and in 56.2% and 50.0% of the CD and SMS subgroups, respectively. In none of FA patients, were E1 values below the normal range. After mucosal recovery, E1 concentrations in patients with CD and SMS increased, suggesting that villous atrophy can diminish exocrine pancreatic secretion. In 18 out of 19 CD and SMS patients with abnormal E1 concentrations, monitored for at least 12 months of a gluten-free diet, abnormal E1 concentrations increased above the cut-off value to normal range. Two out of the 54 referred patients were finally diagnosed as having CF, one with stable low E1 levels and the second with finally normal values.

CONCLUSIONS

The exocrine pancreatic function is decreased in villous atrophy regardless of underlying disease. The specificity of the fecal elastase-1 test in the differentiation between 'primary' exocrine pancreatic insufficiency and intestinal malabsorption with mucosal atrophy is low. After mucosal regeneration, fecal elastase-1 specificity is high.

Parallel secretion of pancreatic phospholipase A(2), phospholipase A(1), lipase, and colipase in children with exocrine pancreatic dysfunction

The cosecretion of pancreatic lipase and colipase are important in normal fat digestion. As adsorption of phosphatidylcholine to the lipid substrate interferes with lipase activity, hydrolysis to lysophosphatidylcholine with subsequent desorption is also essential for fat digestion. There are some data regarding the secretion of pancreatic phospholipases in normal adults but none in children or patients with pancreatic disease. In the present study, we aimed a) to develop an accurate fast assay method to measure phospholipase A(2) and b) to determine the secretion rate of pancreatic phospholipase A(2) and whether it is cosecreted with lipase and colipase in children with exocrine pancreatic dysfunction. Nine male patients aged 0.5 to 16 y (seven with cystic fibrosis, two with malabsorption) underwent pancreatic stimulation tests. Their colipase and lipase secretion rates were measured by titrimetric methods and phospholipase A(2) and A(1) by phosphorus magnetic resonance spectroscopy ((31)P NMR). It was found that the phospholipases, colipase, and lipase were absent in the two patients with pancreatic insufficiency. In patients with normal absorption, there were marked inter-and intrasubject variations of lipase, colipase, and phospholipase secretion rates that were consistent with the degree of exocrine pancreatic dysfunction. However, in the three 20-min stimulation periods of the pancreatic function test, pancreatic phospholipase is cosecreted with lipase and colipase, and average colipase and phospholipase A(2) secretion rates follow a similar or parallel pattern. These findings are consistent with the important role of pancreatic phospholipases in intestinal phospholipid hydrolysis leading to the desorption of phospholipids from the lipid substrate and enhancing lipid hydrolysis and phospholipid absorption.

Intestinal trehalase activity in a UK population: establishing a normal range and the effect of disease

Trehalose is a disaccharide, the main dietary source being mushrooms. It has been approved as an additive in the preparation of dried food. Isolated intestinal trehalase deficiency is found in 8% of Greenlanders, but is rare elsewhere. The normal range of trehalase activity and the incidence of isolated trehalase deficiency in the UK have not been reported. Patients (n 400) were investigated for suspected malabsorption. Endoscopic distal duodenal biopsies were taken for histological assessment and maltase, sucrase, lactase and trehalase estimation. Disaccharidase activities were determined by Dahlqvist's technique (Dahlqvist, 1968). Most patients (n 369) had normal duodenal histology. In these, square root transformation of trehalase activity produced a normal distribution. The normal range (mean +/- 2 SD) was 4.79-37.12 U/g protein. One patient had an isolated borderline trehalase deficiency. The thirty-one patients with villous atrophy had significantly reduced disaccharidase activities. With ingestion of a gluten-free diet, maltase, sucrase and trehalase activities recovered to normal in most patients, whereas lactase activity did not. The normal range and very low incidence of isolated enzyme deficiency is comparable with that described in populations from the USA and mainland Europe. Activity is significantly reduced in untreated coeliac disease and recovers with treatment with a gluten-free diet. There is no place for routine determination of trehalase activity in the UK population and there should be no concern over the introduction of trehalose-containing dried foods.

Low trehalase activity is associated with abdominal symptoms caused by edible mushrooms

BACKGROUND

The purpose of the study was to evaluate whether maldigestion of trehalose causes abdominal symptoms and which available diagnostic method best distinguishes intolerant from tolerant subjects.

METHODS

A 25-g oral trehalose load test was performed in 64 subjects. The 19 experiencing clear symptoms constituted the trehalose-intolerant subjects. Changes from base-line levels of blood glucose, breath hydrogen, and methane and symptoms were recorded after the test. Trehalase activity was determined in serum and on a duodenal biopsy specimen obtained by endoscopy.

RESULTS

Intolerant subjects were best differentiated from tolerant subjects by changes in breath gases (hydrogen and methane) and duodenal trehalase to sucrase ratio. The change in breath gases correlated inversely with duodenal trehalase activity, duodenal trehalase to sucrase ratio, and plasma trehalase activity. The correlation between serum and duodenal trehalase activities was on the order of 0.6. Two subjects were found to have trehalase deficiency.

CONCLUSIONS

It is obvious that trehalose maldigestion can cause symptoms similar to those of lactose maldigestion and intolerance. Three factors control the genesis of symptoms: 1) the activity of small-bowel trehalase: if it is low, trehalose is maldigested and more trehalose is passed into the colon; 2) the maldigested trehalose, which causes osmotic water flow into the colon, resulting in loose stools and diarrhea; and 3) most importantly, the microflora of the colon, from which symptoms will arise if there are bacteria capable of producing gases from maldigested trehalose. If colonic bacteria cannot produce gases, then distention of the abdomen and intestinal gas expulsion as eructations and flatus will not occur.

Further studies on the etiopathology of malabsorption syndrome in broiler chickens

The paper presents two cases of malabsorption syndrome in broiler chickens. The results indicate that the etiological factor appears to be the virus agent which causes necrosis in extra-excretional parts of the pancreas. During the course of the disease disorders in the enzymatic activity of gammaglutamyltransferase, leucylaminopeptidase and alanylaminopeptidase were observed. It consequently leads to the deterioration of intestines digestion and resorption of feed components. Application of Selcewet-Polfa to the diseased birds improved the health of the birds, morphological picture of peripheral blood and mineralisation of thigh bones. No radical improvement in the compensation of the final body weight was recorded.

[Intra-digestive fermentation in intestinal malabsorption syndromes: relations with elevated serum activity of gamma-glutamyl-transpeptidase]

The aim of this prospective study was to examine the relationship between gastrointestinal ethanol production ("Mei-Tei-Sho" syndrome described in Japan) and biological liver dysfunction associated with intestinal malabsorption syndromes.

METHODS

Sixty-five patients with malabsorption-diarrhea underwent 98 simultaneous measurements of plasma gamma-glutamyl-transpeptidase and of faecal ethanol concentrations; in 5 cases, ethanolemia and faecal ethanol concentrations were measured after a 250 g rice-meal; in 1, ethanol concentration was measured in a sample of caecal liquid in hours following local instillation of fructose (40 g).

RESULTS

Faecal ethanol was detected at least once in 60/65 patients (74/98 measurements, maximum 3.50 g*L-1), more often (98.0%, P < 0.001) in 51 patients with gamma-glutamyl-transpeptidase above 38 IU/L. Eating rice increased the faecal ethanol concentration in 5 patients, 2 of whom had measurable ethanolemia (0.20 and 0.47 g*L-1). Ileo-caecal ethanol concentration following local fructose instillation was 11.8 g*L-1.

CONCLUSION

Endogenous gastrointestinal ethanol production contributes to elevated gamma-glutamyl-transpeptidase activity observed during malabsorption syndromes.

Stunting syndrome in broilers: effect of age and exogenous amylase and protease on performance, development of the digestive tract, digestive enzyme activity, and apparent digestibility

Day-old male, meat-type chicks raised in brooder batteries were infected by orally administering an inoculum prepared from intestines of broiler chicks infected with stunting syndrome (SS). Naive controls were kept in a parallel room. The chicks were fed a commercial starter diet supplemented with two levels of enzyme preparations to 14 d of age. The experiment was continued to the age of 6 wk in order to estimate compensatory feed intake and growth. In a parallel study, digestibility of the feed was determined from 1 to 3 wk of age with control or inoculated chicks. The enzymes amylase and proteases were produced by Bacillus subtilis and Penicillium emersonii. Enzyme supplementation had no effect on feed intake, growth, or feed utilization, or on digestibility of fat, starch, protein, or energy. Because enzyme supplementation did not consistently affect performance of chicks and no interactions were observed between enzyme supplementation and infection status, data are presented for effects of infection only. Inoculation of SS-infective material reduced performance to 4 wk. Compensatory growth and feed intake were observed from the age of 4 wk onward. At the age of 6 wk the slight retardation of the inoculated chicks was not significant. On Week 1, retention of fat, starch, protein, and energy was significantly depressed in the inoculated chicks. At the age of 2 wk, retention of starch was not depressed, and at the age of 3 wk, the only consistent depression was that observed for fat. The proventriculus weight and content were consistently higher in inoculated chicks, as were the small intestine and intestinal content. The pH of the gizzard content was higher, and that of the small intestine content was lower, in the inoculated birds than in their control counterparts. Stunting syndrome infection was accompanied by a significant depression of trypsin activity in the pancreas at the age of 1 and 2 wk. At these periods, amylase and chymotrypsin were not affected. At 6 wk of age, the activities of amylase, trypsin, and chymotrypsin in the pancreas were higher in the inoculated than in the control birds. In the intestinal chime, amylase, trypsin, and chymotrypsin activities were lower in the inoculated birds on Week 1 and 2 (NS for amylase on Week 1). On Week 6, the activity of all enzymes assayed was higher in the inoculated birds (NS for amylase). It is suggested that the main factors depressing feed intake and growth in SS-infected birds are most probably beyond those of digestion.

Pathophysiology of the pancreatic defect in Johanson-Blizzard syndrome: a disorder of acinar development

We compared pancreatic acinar and ductal secretion in two patients with Johanson-Blizzard syndrome, age-matched control subjects, and patients with other primary pancreatic diseases. Patients with Johanson-Blizzard syndrome had preservation of ductular output of fluid and electrolytes, as in patients with Shwachman syndrome but differing from those with cystic fibrosis, who have a primary ductular defect. They also had decreased acinar secretion of trypsin, colipase and total lipase, and low serum immunoreactive trypsinogen levels, consistent with a primary acinar cell defect.

[Exocrine pancreas involvement in chronic enteropathies in infants and children]

On a number of 135 cases of chronic enteropathies in patients aged 6 months--15 years, the trypsin, amilasis and lipasis levels in duodenal aspirate were investigated. In a high number, the decrease of pancreatic enzymes activity was noted and the majority of cases were accompanied by a marked dystrophy (grades II or III). Thus, it was not possible to indicate whether the low levels were primary or secondary determined.

[Comparative studies of the activity of disaccharidases in the mucosa of the small intestines in dystrophic, formerly hypotrophic-born young children and of patients with flat mucosa of various etiology]

The disaccharidase activities of the mucous membrane of the small intestine were determined in formerly hypotrophic children who showing a dystrophy with a morphological normal mucosa (n = 36), patients with a flat mucosa caused by enteral protein intolerances of different genesis (n = 27), patients with a morphologically and functionally normal mucosa (n = 51). In about half of the former small-for-date children were shown activities lower than the simple standard deviation of the normal value, for lactase n = 17, for sucrase n = 14, for maltase n = 12. Some children showed pathologically reduced activities even below the double standard deviation for the normal value: lactase n = 8, sucrase n = 5, maltase n = 3.

Stunting syndrome in turkeys. Development of an experimental model

Experiments were conducted to establish a stunting syndrome (SS) model to facilitate research on nutritional aspects of enteric disorders of poults. One-day-old turkeys were dosed per os with tryptose phosphate broth (TPB) (controls) or inoculum (inoculated). The inoculum was prepared by homogenizing intestines from 11-day-old commercial poults diagnosed to have SS in TPB (1:0.5 [wt:wt]). Subsequently, intestines from 8-day-old inoculated poults from the previous experiment were used. Inoculation reduced growth (P less than 0.001) and feed consumption (P less than 0.001) at 8 and 14 days of age. In Expts. 1, 2, and 3, gain of inoculated poults was 60.9%, 58.8%, and 52.6% that of controls up to 8 days of age and 77.9%, 76.6%, and 80.9% that of controls from 8 to 15 days of age, respectively. Feed conversion was impaired (P less than 0.001) up to 8 days of age. The activity of maltase and sucrase in the jejunum and of pancreatic enzymes was determined every 2 days up to 13 days of age. Inoculation decreased (P less than 0.001) maltase and sucrase starting at 3 days of age (i.e., maltase activity was 17.45 and 1.70 mumols maltose hydrolyzed/hr.mg protein in control and inoculated poults, respectively). Inoculation had no effect on pancreatic lipase, amylase, or trypsin.

[Absorption disorders following gastric resection--morphological and enzyme-histochemical observations on the small intestinal mucosa]

For the purpose of studying digestion and absorption disorders following stomach surgery, particularly with respect to membrane digestive functional disorders, morphological and enzyme-histochemical observation of the small intestinal mucosa was performed, and a comparison was done between the partial gastrectomy group (59 cases), and the total gastrectomy group (52 cases). The following results were obtained: 1) The small intestinal mucosa showed a tendency to significant villous atrophy in post-operative groups. 2) There was a significant decrease in the disaccharidase activity, especially in the small intestine of the total gastrectomy group. ALP, LAP and gamma-GPT activity also decreased, or disappeared in the small intestines showing villous atrophy. 3) In the atrophied mucosa which showed a marked decrease in membraneous enzyme activity, poorly-formed, irregularly sized microvilli accompanied by glycocalyx irregularity and disappearance were recognized under the electron microscope. The above mentioned morphological and enzyme-histological findings in the small intestinal mucosa, were strongly reflected in both post-operative progress and clinical symptoms.

[Current diagnostic method for saccharose-isomaltose malabsorption]

The authors present the cases of 4 children who suffered from saccharose-isomaltose malabsorption. The clinical symptoms developed following artificial feeding. The diagnosis was made by the histological examination of small intestine samples and with the simultaneous measurement of disaccharide enzyme activity. The histological picture and activity of lactase enzyme were practically normal. The saccharose H2 breath test gave only in 1 case positive result. The treatment of the children required saccharose-free diet. The tolerance showed no improvement during the treatment.

[Monosaccharide malabsorption syndrome]

Pathogenesis of disorders in the transport of monosaccharides in the intestinal epithelial cells has been considered. Criteria for the diagnosis of primary and secondary malabsorption of monosaccharides have been discussed. Characteristics of the clinical picture, differential diagnosis and therapeutic measures have been presented. A case has been described of primary malabsorption of glucose and galactose in a woman aged 38 years. Possible ways of compensation of the transport disorders with age are discussed. It is noted that in chronic enteritis the enzymatic system in the intestinal mucosa is impaired earlier than the transport system.

Elevated levels of serum pancreatic secretory trypsin inhibitor (PSTI) in patients with malabsorption syndrome

Serum pancreatic secretory trypsin inhibitor (PSTI) was measured by radioimmunoassay in 5 patients with malabsorption syndrome. The serum level of PSTI was elevated to 123.8 +/- 25.8 ng/ml (Mean +/- SE) in patients with malabsorption syndrome, which was significantly higher than the 16.6 +/- 0.7 ng/ml level seen in 116 healthy control subjects. Serum PSTI levels in 5 patients with malabsorption syndrome showed inverse correlations with serum levels of cholesterol, cholinesterase and amylase, and not with serum levels of vitamin E, carotene, apoprotein A-IV, albumin, nor with immunoreactive elastase 1, respectively. These results suggest that elevated levels of serum PSTI represent a state of malnutrition due to impaired intestinal absorption.

Fecal chymotrypsin levels in children with pancreatic insufficiency

The fecal chymotrypsin (FC) levels in samples collected over 24 h were determined by a new commercial colorimetric method from Boehringer Mannheim in 82 children suffering from various pancreatic disorders. The patients were divided into 4 groups, in accordance with the following etiologies: cystic fibrosis of the pancreas (CFP), chronic severe hepatic disorders (CSH), primary malabsorption syndrome (PMS) and malnutrition due to nondigestive causes (M). The control group comprised 48 children of similar ages. The 24th FC levels as U/g (mean +/- SD) were: 34 +/- 6 in the control group, 2 +/- 2 in the CFP group, 15 +/- 6 in the M group, 19 +/- 9 in the CSH group and 43 +/- 13 in the PMS group. The differences between the CFP patients and all the other groups were statistically significant. These results indicate that the FC levels may be suitable as a diagnostic indication of CFP and capable of differentiating between this disorder and other causes of pancreatic insufficiency.

Stool chymotrypsin activity measured by a spectrophotometric procedure to identify pancreatic disease in infants

The aim of this study was to assess the analytical performance of the BMC stool chymotrypsin test and its accuracy in diagnosing pancreatic disease in infants. The test utilizes a detergent which solubilizes chymotrypsin bound to stool residues, and a tetrapeptide coupled to p-nitroaniline which is specifically cleaved by chymotrypsin. We employed the IL Multistat at 30 degrees C to monitor enzyme activity as an increase in absorbance at 405 nm. The reaction was linear to 600 U/g stool. Recovery of exogenous chymotrypsin with a single detergent extraction was 98-105%, and of endogenous chymotrypsin (as determined by multiple extractions) 80-97%. Imprecision (CV) was 2.2% within-day and 2.4% between-day for the BMC control, and 2.4-5.2% for stool chymotrypsin in the range 8.3-14.4 U/g. Since the test utilises only 100 mg of stool, inhomogeneity of enzyme distribution was assessed by multiple assays on a single stool, which revealed a range of activity from 4.2-150%. We therefore recommend sampling of each stool in triplicate. With this procedure, chymotrypsin was measured in 220 consecutive stool samples submitted for fat determination from children. Applying the manufacturer's lower reference limit of 4.1 U/g, the following results were obtained (number abnormal/total number): suspected intestinal disease with normal stool fat (5/127); proven intestinal disease and increased stool fat (1/26); untreated cystic fibrosis (CF) with (19/22), and without (0/3) steatorrhea; CF with pancreatic insufficiency on replacement therapy (4/42).(ABSTRACT TRUNCATED AT 250 WORDS)

[Functional characterization of luminal enterocyte membranes of the small intestine mucosa using isolated brush border membranes]

Atrophy of the small intestinal mucosa is functionally characterized by a reduction in non-electrolyte transport in vivo. In order to elucidate the cellular defect being responsible for this malabsorption, we have studied the Na+-dependent D-glucose accumulation as well as the activities of aminopeptidase M and maltase in brush border membrane vesicles prepared from jejunal self-emptying blind loops and corresponding intestinal segments of sham-operated control rats. Membrane vesicles from atrophic mucosa did not show any differences in D-glucose uptake or in enzyme activities when compared with those derived from normal intestine. Thus it is unlikely that the impaired non-electrolyte absorption in the atrophic mucosa in vivo is due to a defect in cellular transport processes. It is more probable that the functional impairment is the result of the diminished absorptive surface in this pathophysiological condition.

Lactose digestion by human jejunal biopsies: the relationship between hydrolysis and absorption

The relationship between lactose hydrolysis and absorption of released glucose was investigated by determining the kinetics of lactose digestion by jejunal biopsies incubated in vitro. Lactase activity in intact biopsies correlated with conventional assay of tissue homogenates (r = 0.85, p less than 0.001), and glucose uptake from 28 mM lactose was directly proportional to lactase activity (r = 0.95, p less than 0.001) in 21 subjects with normal lactase levels, six with hypolactasia (primary or secondary to coeliac disease) and two with lactose intolerance but normal lactase activity. Kinetic analysis at 0.56-56 mM lactose in five normal subjects showed saturable kinetics for hydrolysis (app Km = 33.9 +/- 2.2 mM; app Vmax = 26.5 +/- 1.1 nmol/min/mg dry weight) but glucose uptake could be fitted to a model either of saturable uptake (app Kt = 47.2 +/- 0.3 mM; app Jmax = 14.1 +/- 0.2 nmol/min/mg) or saturable uptake plus a linear component (app Kt = 21.3 +/- 1.15; app Jmax = 4.59 +/- 0.12; app Kd = 0.093 +/- 0.010 nmol/min/mg/mM). The proportion of glucose taken into the tissue did not significantly exceed 50% of the total released at any lactose concentration suggesting the lack of an efficient capture mechanism for the released glucose. The results suggest that lactose hydrolysis is the rate limiting step in the overall absorption of glucose from lactose in vitro, and that the relationship between hydrolysis and absorption is the same in normal subjects and in hypolactasic subjects.

Clinical studies of intestinal folate conjugases

Clinical differences between the two human intestinal mucosal folate conjugases were assessed by measurement of their activities in normal individuals and in patients with chronic diarrhea of differing causes. Intracellular folate conjugase (ICFC) was 15-fold more active than brush border folate conjugase (BBFC) in jejunal mucosa from seven obese patients undergoing elective gastric bypass surgery. The activity of ICFC was similar among normal volunteers and patients with diarrhea of unknown origin (DUO), gluten-sensitive enteropathy (GSE), inflammatory bowel disease (IBD), and the short bowel syndrome (IBD-SBS). By contrast, BBFC, sucrase, and lactase were decreased significantly in GSE, and BBFC was increased in IBD-SBS. The activity of BBFC correlated with lactase and with sucrase in the normal subjects and in patients with DUO, whereas no correlations were found with the activity of ICFC in any group. Our clinical studies confirm that ICFC and BBFC are different enzymes. ICFC is not affected by intestinal disease, whereas the activity of jejunal BBFC, like that of other brush border enzymes, is decreased by mucosal injury and is also capable of adapting to distal small intestinal disease or surgical resection.

Ornithine transcarbamylase and disaccharidase activities in damaged intestinal mucosa of children--diagnosis of hereditary ornithine transcarbamylase deficiency in mucosa

Ornithine transcarbamylase (OTC) and disaccharidase activities were measured in the intestinal mucosa from 182 children. Sixty-nine had normal mucosa, whereas the others had different degrees of mucosal damage. Brush border disaccharidases are significantly decreased in all degrees of villous atrophy. In contrast, OTC is not affected in moderate atrophy and only slightly decreased in severe atrophy. Consequently, the OTC-to-lactase ratio increases with the degree of atrophy and permits discrimination between normal and damaged mucosa. The assay of OTC activity in intestinal mucosa for the diagnosis of hereditary deficiency in male hemizygote patients generally provides nonambiguously low results, whereas in heterozygote females the amount of residual activity is in the range of the results found in damaged mucosa.

Toxicity mechanisms of wheat and other cereals in celiac disease and related enteropathies

This paper is a critical appraisal of current theories on the mechanisms of toxicity of wheat and other cereals in celiac disease and some related enteropathies. The "peptidase deficiency," "primary immune defect," and "gluten-lectin" theories on celiac disease are examined and critically discussed on the basis of the relevant data available in 88 references. Special attention has been paid in this review to the nature of the cereal components triggering the appearance of toxic symptoms and signs in celiac disease as well as to underlying action mechanisms. The gluten-lectin theory is the one best able to explain, in addition to celiac disease, some secondary intolerances that may occur in temporarily predisposed individuals as a consequence of several causes, including viral hepatitis and intestinal infections, as well as the occurrence of intestinal lesions in healthy subjects administered very high amounts of gluten.

Disaccharidase activities, jejunal morphology, and carbohydrate tolerance in children with chronic diarrhea

Children with chronic diarrhea were examined for their carbohydrate tolerance, small bowel morphology, and specific disaccharidase activities to determine whether disaccharidase enzymatic activity is related to villus height and thus may be viewed as an independent variable that controls digestive capacity. Results indicated that 65-78% of all abnormal biopsy samples had specific disaccharidase activities that fell within the normal range. Clinical disaccharide tolerance studies indicated that specific enzyme activity did not correlate with disaccharide tolerance.

The importance of protease histochemistry in pathology

The histochemical demonstration of the activities of proteases, based in the majority of cases on the use of discriminating synthetic substrates (aminoacyl or peptidyl derivatives of 4-methoxy-2-naphthylamine [MNA]), has proved very valuable in pathology. Its importance is illustrated by three topics investigated in our laboratory, namely lymphocytes, malabsorption syndrome and atherosclerosis.

Clinical significance of enzymatic deficiencies in the gastrointestinal tract with particular reference to lactase deficiency

The study of deficiencies of small intestinal brush-border hydrolases increased our knowledge about the specific functions of hydrolases in the digestion of smaller molecules on the microvillus surface of the absorptive cells. The sucrase-isomaltase (SI) complex has been shown to be synthesized as a precursor (pro-sucrase-isomaltase) which is then incorporated into the membrane. The hydrophobic N-terminal end of the molecule is anchored in the lipid bilayer. In SI deficiency the molecular base of the disease is still not clear. Absence of SI activity could be due to complete lack of precursor synthesis or to structural changes within the N-terminal end of the SI-complex. Deficiencies of peptide hydrolases have not been reported with the exception of enteropeptidase (EP). Here a congenital deficiency of the enzyme was observed as the primary defect in enzyme synthesis within the enterocytes and as a secondary defect due to exocrine pancreatic insufficiency. In contrast to the primary EP deficiency, the activity of EP can be restored in the cases of exocrine pancreatic insufficiency by treatment with pancreatic extracts. Primary lactase deficiency exists in various forms. Besides congenital lactase deficiency, the late onset or adult type of lactase deficiency has been observed. The latter occurs in many different ethnic groups around the world. Here, using gel electrophoresis and immunoelectrophoresis, the lack of enzyme activity could be shown to be a primary defect in enzyme protein synthesis. In man and in the rat, two different lactases have been identified. In contrast to adult lactase, fetal lactase contains sialic acid at the end of carbohydrate side chains.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical quantification of crypt hyperplastic villous atrophy by aldolase activity assay

Aldolase activity with the two substrates fructose-1-phosphate and fructose-1,6-diphosphate was measured in the homogenate of small intestinal biopsy specimens from children with different malabsorptive diseases (celiac disease, cow's milk protein intolerance, infectious diarrhea, giardiasis, and Crohn's disease) and controls. It is demonstrated that the ratio of fructose-1,6-diphosphate/fructose-1-phosphate activity, which reflects the relative amounts of the crypt enzyme aldolase A (EC 4.1.2.13) and the villous enzyme aldolase B (EC 4.1.2.7), correlates very well with both the ratio of crypt to villous height (correlation factor r = 0.92) and the mitotic index (r = 0.80).

[Lysozyme concentrations in the intestinal mucosa in malabsorption syndromes and chronic inflammatory intestinal diseases]

Lysozyme levels were determined in the mucosa of gut in 80 children with chronic inflammatory bowel disease, malabsorption and acrodermatitis enteropathica.l Levels of lysozyme in the mucosa of colon were found to be significantly higher in cases with chronic inflammatory bowel disease, whereas in children with malabsorption (celiac disease) concentration of lysozyme in the mucosa of small intestine were significantly lower compared to a control group. In a 4 months old boy with acrodermatitis enteropathica there was a low level of lysozyme in the mucosa of the small intestine. After therapy with zinc for one year concentration of lysozyme was normalized.

Enzymatic activities in jejunal biopsy specimens from patients with the stagnant-loop syndrome

The activity of the marker enzymes lactase, sucrase, neutral alpha-glucosidase, alkaline phosphatase, gamma-glutamyl transferase, leucyl-beta-naphthylamidase (brush border); 5-nucleotidase (basolateral membrane); and acid phosphatase and N-acetyl-beta-glucosaminidase (lysosomes) in jejunal biopsies from patients with the stagnant-loop syndrome and controls was studied. The activity of gamma-glutamyl transferase was increased in the patient group; the activity of the other enzymes did not differ significantly in patients and controls. The DNA to protein ratio was increased in the patient group. The results do not support the hypothesis of epithelial damage in the human stagnant-loop syndrome.

[Trehalose-load test in gastroenterology]

In 35 infants trehalose-load-tests were carried out, biopsies of the intestinal mucosa of each patient were taken, and examined histologically. Furthermore, the enzyme activities of trehalase and lactase in each biopsy were determined. It was possible to demonstrate that morphology and function of the intestinal mucosa correlate differently depending on the severity of the mucosal damage. If there is only moderate mucosal damage, a rather weak correlation is seen either for the trehalose-load-test or for the disaccharidase activities with morphological changes. If damage was absent or severe, correlation improved. Both methods in comparison show a better correlation between trehalase activity and morphology than between trehalose-load-test and morphology. Furthermore, trehalase activity corroborated the histological findings better than lactase activity.