Duodenal Disaccharidase Activities in the Follow-up of Villous Atrophy in Coeliac Disease

Background: In active coeliac disease, mucosal atrophy is associated with a marked decrease in intestinal disaccharidase enzyme activities. We investigated the value of duodenal mucosal disaccharidases to predict the severity of mucosal villous atrophy and its recovery in 50 patients with coeliac disease. Methods: Duodenal mucosal histology and disaccharidase activities were studied at least twice with a mean interval of 9 months. Histology of specimens from all patients was examined by the same pathologist blinded to the data on disaccharidase activities. Mucosal damage was scored into four groups as follows: Grade 0 = normal mucosa; grade 1 = slight villous atrophy, that is, cryptic component 30%- 50%; grade 2 = moderate villous atrophy, that is, cryptic component 50%-90%; grade 3 = severe villous atrophy, that is, cryptic component >90%. The enzyme activities of the disaccharidases were determined as U/g protein. Results: Duodenal mucosal disaccharidase activities were good predictors of the grade of mucosal villous atrophy. Positive predictive values for moderate or severe villous atrophy were 90% for maltase (maltase activity <150 U/g protein), 86% for sucrase (<40 U/g protein) and 71% for lactase (<20 U/g protein). Accordingly, negative predictive values, that is, none or only minimal villous atrophy (grades 0 or 1) with normal disaccharidase activities, were 71% for maltase, 70% for sucrase and 63% for lactase. Conclusions: The increase in duodenal disaccharidase activities correlated with recovery of the mucosa based on histology. Besides the histological examination, measurement of disaccharidase activities offers an additional tool to evaluate response to a gluten-free diet in patients with coeliac disease.     

Alterations in duodenal disaccharidases in chronic smokers.

OBJECTIVE: To assess the effect of smoking on activity of intestinal disaccharidases. METHODS: The study was conducted on patients with non-ulcer dyspepsia who were smokers (n=20) or non-smokers (n=20). Smokers were classified according to smoking index into mild, moderate and heavy smokers. Biopsy specimens were taken from the second part of the duodenum at endoscopy and examined histologically, and for disaccharidase (lactase, sucrase, maltase and trehalase) activities. RESULTS: Mean duration of symptoms was more in smokers than in non-smokers. None of the smokers had endoscopic evidence of duodenal inflammation. Lactase and trehalase levels were significantly decreased in smokers. There was no difference in enzyme levels between mild smokers and non-smokers. Decreased lactase, maltase and trehalase activities were observed in moderate smokers compared to mild smokers. Duration of symptoms had no relation to enzyme activities. CONCLUSIONS: Intestinal disaccharidase levels are diminished by smoking.     

A Retrospective Assessment of the Clinical Value of Jejunal Disaccharidase Analysis

Duncan A, Park RPR, Lee FD, Russell RI. A retrospective assessment of the clinical value of jejunal disaccharidase analysis. Scand J Gastroenterol 1994;29:1111-1116.

Background: The measurement of jejunal disaccharidases is used by several gastroenterologists when investigating suspected small-bowel disease. The clinical value of this analysis is assessed.

Method: The histology and disaccharidase results in 1585 jejunal biopsy specimens were reviewed retrospectively.

Results: Disaccharidase and histology results concurred in most cases (72%). However, disaccharidases were an insensitive indicator of small-bowel disease: low levels were found in only 65% of coeliac patients with villous atrophy, 15% of patients with giardiasis, and 6% of patients with villous atrophy associated with non-coeliac histology. Low disaccharidase levels were sometimes found in patients with normal histology (1.6%) and when biopsy specimens were unwittingly taken from non-jejunal sites (1.4%). Isolated low lactase activities were found in 3.2%. Usually this finding was not clinically relevant because patients had no symptoms of lactose intolerance (38%), had another diagnosis that responded to appropriate treatment (8%), or had no response to a low-lactose diet (14%). In 16 patients sucrase activities were markedly low, and this investigation proved central to the diagnosis of sucrase-α-dextrinase deficiency, which was subsequently confirmed in 9.

Conclusion: Jejunal disaccharidases are clinically useful only in the diagnosis of sucrase-α–dextrinase deficiency. We recommend that their measurement be reserved for the investigation of patients suspected of having this condition.     

Correlation of intestinal disaccharidase activities with the C/T-13910 variant and age

AIM： To correlate the C/T-13910 variant, associated with lactase persistence/non-persistence （adulttype hypolactasia） trait, with intestinal disaccharidase activities in different age groups of the adult population.
METHODS： Intestinal biopsies were obtained from 222 adults aged 18 to 83 years undergoing upper gastrointestinal endoscopy because of unspecified abdominal complaints. The biopsies were assayed for lactase, sucrase and maltase activities and genotyped for the C/T-13910 variant using PCR-minisequencing.
RESULTS： There was a significant correlation between lactase activity and the C/T-13910 variant （P 〈 0.00001）. The mean level of lactase activity among subjects with C/C-1391o genotype was 6.86± 0.35 U/g, with C/T-13910 genotype 37.8 ± 1.4 U/g, and with T/T-13910 genotype 57.6± 2.4 U/g protein, showing a trimodal distribution of this enzyme activity. Significant differences were also observed in maltase activities among individuals with different C/T-13910 genotypes （P = 0.005）. In contrast, in sucrase activity, no significant differences emerged between the C/T-13910 genotypes （P = 0.14）. There were no statistical differences in lactase （P = 0.84）, sucrase （P = 0.18）, or maltase activity （P = 0.24） among different age groups. In the majority （〉 84%） of the patients with the C/C-13910 genotype associated with lactase non- persistence, the lactase activity was less than 10 U/g protein.
CONCLUSION： Our study demonstrates a statistically significant correlation between the C/T-13910 genotype and lactase activity and this correlation is not affected by age in adults but the cut-off value of 20 U/g protein used for the diagnosis of lactase non-persistence might be too high.     

Disaccharidase activity in the small intestine of susceptible and resistant mice after primary and challenge infections with Giardia muris.

The activities of four disaccharidases were examined in resistant (C57Bl/6) and susceptible (C3H/HeN) mice during the primary infection with Giardia muris and after challenge with either trophozoite extract or cysts. Significant decreases in lactase, sucrase, trehalase, and maltase activities in C57Bl/6 mice and lactase and sucrase activities in C3H/HeN mice in the anterior 25% of the small intestine were observed on day 10 after infection. The activities of maltase, sucrase, trehalase, and lactase in the jejunum of C3H/HeN mice were significantly reduced after challenge with trophozoite extract, when compared with the uninfected or infected, but not challenged animals. Decreases in enzyme activities of C3H/HeN mice were evident as early as 12 hours after challenge with the extract. The resistant C57Bl/6 mice showed little change in disaccharidase activity after challenge with trophozoite extract. On the other hand, challenge with cysts resulted in a few decreases in disaccharidase activities in both strains of mice: C57Bl/6 mice showed decreases in the duodenum, while disaccharidases of C3H/HeN mice had lower activity more posteriorly. Thus, challenge with parasite antigen results in a more severe disaccharidase deficiency in susceptible hosts when compared with resistant ones.     

Adequacy of endoscopic biopsy specimens for disaccharidase assays

Intestinal mucosa from 40 patients obtained by fiber-endoscopic biopsy was assayed for disaccharidases to determine suitability of this tissue for assay. The combined specimens from each patient provided 4.7–38.7 mg of tissue, adequate in all instances for duplicate determinations of protein, lactase, sucrase, and maltase. Tissue remained for assays of palatinase in 39 instances, trehalase and cellobiase in 37, and alkaline phosphatase in 22 cases. Twenty-four subjects had normal lactose tolerance tests and normal sucrase/lactase ratios. Thirteen patients with abnormal oral lactose tolerance tests were identified as having a primary low lactase activity on the basis of elevated sucrase/lactase ratios. This ratio was most helpful in making the diagnosis of a primary low lactase, since the mucosal specimens were not obtained from comparable areas. Tissue from three subjects with an abnormally low maltase was unsuitable for diagnosis. Endoscopic biopsy of mucosa appears to be satisfactory for disaccharidase assays in most instances.This work was supported by the Medical Research Service of the Veterans Administration.     

Ligation or external fistulation of the common bile duct in the rat. II. Intestinal disaccharidase activities.

72 h after ligation or external fistulation of the common duct the activities of maltase, sucrase and lactase in the homogenate of the small intestinal mucosa of the rat were determined. The experiments were performed in connexion with intestinal perfusion studies, and the disaccharidase activities were measured in unperfused intestinal segments as well as in intestinal loops which had previously been perfused with a sucrose-containing solution. After bile duct ligation, the sucrase and maltase activities in a previously perfused intestinal loop were not different from those in sham-operated animals, the lactase activity was diminished. In a nonperfused segment, the sucrase activity was greater, the maltase activity was unchanged, and the lactase activity was lower than in control animals. After bile duct fistulation, the sucrase, maltase and lactase activities in a perfused segment were lower than in sham-operated rats. In a nonperfused loop, the sucrase activity was greater, the maltase activity was unchanged, and the lactase activity was lower then in the corresponding control group. These data suggest that bile is a factor which influences the total mucosal disaccharidase activities, and, probably, the intracellular enzyme distribution.     

Disaccharidase deficiency in infants with cow's milk protein intolerance. Response to treatment

7 infants, aged 5 weeks to 11 months, with clinically documented intolerance to cow's milk protein, chronic diarrhea, and failure to thrive, underwent small intestinal (peroal, suction) biopsy before and after withdrawal of milk proteins. Mucosal specimens were examined by light microscopy and assayed for disaccharidase activities. In all patients, moderate to severe mucosal changes were presented, associated with marked inflammation of lamina propria and damages to the brushborder. Disaccharidase activities (lactase, sucrase, maltase and palatinase) were markedly depressed in all. Follow-up biopsies were obtained in 6 infants, after 3-5 months on a milk-protein-free diet. At the time of the second biopsy, the disaccharidase activities had risen significantly and histologic improvement had occurred in each instance. In infancy, intestinal mucosal lesions due to intolerance to cow's milk protein are histologically indistinguishable from those seen in gluten-sensitive enteropathy and are associated with marked secondary disaccharidase deficiencies. Following therapy, the activity of the disaccharidases become normal or near normal prior to the complete morphologic recovery of the small intestinal mucosa.     

Dietary zinc and metallothionein on small intestinal disaccharidases activity in mice

AIM: To examine the effect of increasing dietary zinc (Zn) intake and the lack of metallothionein (MT) expression on activity of small intestinal disaccharidases. METHODS: MT-Ⅰ and Ⅱ knockout (MT-/-) and wild-type (MT+/+) female mice at 3.5 wk of age were randomly fed with a diet containing 2 (2 Zn), 15 (15 Zn) or 50 (50 Zn) mg Zn/kg (n = 8/group/genotype) for 5 wk. Small intestinal segments (duodenum, jejunum and ileum) were collected and either fixed in 10% formalin for histological analysis or snap froze...     

Intestinal disaccharidase activities and activity ratios in a group of 60 adult German subjects

Lactase, maltase and sucrase activities were determined in samples of jejunal mucosa obtained by suction biopsy from 60 healthy adult German males. Primary adult hypolactasia ("lactase deficiency") was found in 8 subjects (13%). Maltase:lactase and sucrase:lactase activity ratios were significantly higher in post-weaning hypolactasia than in adult lactase persistence. Sources of variation in disaccharidase activities measured in biopsy tissue homogenates are discussed.     

The influence of age on intestinal dipeptidyl peptidase IV (DPP IV/CD26), disaccharidases, and alkaline phosphatase enzyme activity in C57BL/6 mice

The objective of this study was to determine and describe the age-related changes in intestinal brush border membrane enzyme activities that occur in C57Bl/6 mice. Specifically, jejunal, duodenal, and ileal dipeptidyl peptidase IV/CD26, disaccharidase (lactase, sucrase, and maltase), and alkaline phosphatase activities were determined. A significant correlation between analyzed intestinal brush border membrane enzyme activities and animal age was found. Our study revealed that intestinal dipeptidyl peptidase IV/CD26, lactase, sucrase, maltase, and alkaline phosphatase activities decline significantly with age (p < .05). Nevertheless, the horizontal (duodenum to ileum) enzyme activity patterns are not affected by age.     

The Influence of Age on Intestinal Dipeptidyl Peptidase IV (DPP IV/CD26), Disaccharidases,and Alkaline Phosphatase Enzyme Activity in C57BL/6 Mice

The objective of this study was to determine and describe the age-related changes in intestinal brush border membrane enzyme activities that occur in C57Bl/6 mice. Specifically, jejunal, duodenal, and ileal dipeptidyl peptidase IV/CD26, disaccharidase (lactase, sucrase, and maltase), and alkaline phosphatase activities were determined. A significant correlation between analyzed intestinal brush border membrane enzyme activities and animal age was found. Our study revealed that intestinal dipeptidyl peptidase IV/CD26, lactase, sucrase, maltase, and alkaline phosphatase activities decline significantly with age (p < .05). Nevertheless, the horizontal (duodenum to ileum) enzyme activity patterns are not affected by age.     

Effects of prolonged alcohol administration and a high carbohydrate-low protein diet on the activities of the jejunal brush border enzymes in the rat.

The effects of prolonged alcohol administration were studied on the brush border enzyme activities of the jejunum in rats receiving either a normal laboratory diet or a high carbohydrate-low protein for several weeks. Alcohol (15%) given in association with the normal diet provoked a stimulation of sucrase, maltase, and lactase activities after four weeks, but no significant modification in aminopeptidase activity. These results obtained for the disaccharidases were very similar to those observed with the high carbohydrate-low protein diet given without alcohol, although major differences were obvious in the timing of enzyme stimulation. In contrast, this dietary condition initiated a drop in aminopeptidase activity. When alcohol was given in association with the high carbohydrate-low protein diet, no modification in aminopeptidase activity was detected and the stimulation for the disaccharidase activities was similar to that observed with the high carbohydrate-low protein diet given alone. The present results suggest that the mechanisms involved in the stimulation of brush border disaccharidase activities were different for alcohol and for the high carbohydrate-low protein diet.     

Influence of exocrine and endocrine pancreatic function on intestinal brush border enaymatic activities.

Digestive enzymatic activities (disaccharidases, alkaline phosphatase, peptide hydrolases) have been determined in the mucosa of 14 patients with chronic pancreatitis. All had an abnormal secretin-pancreozymin test. Four patients had insulin-dependent diabetes mellitus, four a pathological glucose tolerance test. Nine patients had steatorrhoea. Maltase, sucrase, and alkaline phosphatase activity was significantly elevated in patients with exocrine pancreatic insufficiency, whereas those of lactase, trehalase, and peptide hydrolase were normal. Patients with steatorrhoea had higher maltase and sucrase activity than those without steatorrhoea, whereas decreased glucose tolerance had no effect on brush border enzymatic activity. It is suggested thatdecreased exocrine rather than decreased endocrine pancreatic function is responsible for the increase in intestinal disaccharidase and alkaline phosphatase activity, possible by the influence of pacreatic enzymes on the turnover of brush border enzymes from the luminal side of the mucosal membranes or by direct hormonal stimulation though cholecystokinin.     

Disaccharidase levels in the small intestine in patients with diarrhoea following vagotomy and pyloroplasty

Diarrhoea is a common sequel to vagotomy and pyloroplasty but its cause is unknown. One of our patients who developed this complication had an abnormal lactose barium meal and responded well to a lactose-free diet. This led us to make a systematic study of disaccharidase activity in the small intestine in patients with diarrhoea following vagotomy and pyloroplasty.The small-intestinal disaccharidases have been estimated in jejunal biopsy specimens taken from 23 patients suffering from persistent diarrhoea, either continuous or episodic, after vagotomy and pyloroplasty. The disaccharidase values were normal in all but one of these patients. This patient showed hypolactasia but the sucrase and maltase levels were normal. The jejunal biopsy specimen taken from this patient showed a convoluted pattern under the dissecting microscope and severe partial villous atrophy under the light microscope. A repeat jejunal biopsy taken 20 cm beyond the duodeno-jejunal flexure showed similar appearances and also had a low level of lactase. However, two lactose tolerance tests and a lactose barium meal yielded normal results, suggesting that the low level of lactase in the upper jejunum was not a limiting factor in lactose absorption.The finding of one example of a low lactase level among 23 postvagotomy patients corresponds with what is being found in a study of normal subjects at present in progress.In effect, almost all patients with persistent diarrhoea after vagotomy and pyloroplasty have normal small-intestinal disaccharidase activity.     

Intestinal disaccharidase activity following pancreatic duct occlusion in the rat

The influence of pancreatic secretions on growth and brush-border enzyme activity, throughout the entire small intestine, was examined in the rat. Pancreatic secretions were excluded from the gut lumen by stapling the pancreatic ducts, without interruption of bile flow. The entire small intestine was studied as four segments; the duodenum and three distal segments of equal length. Weight of intestine and mucosa, and mucosal sucrase, isomaltase, lactase, and alkaline phosphatase activity were measured 10-15 days following pancreatic duct occlusion, or sham-operation. The duodenum of pancreatic duct-occluded animals exhibited significant hypertrophy. In general, specific and total disaccharidase activities were greater in duct-occluded animals than in controls throughout the intestine. The increase was more pronounced in distal than in proximal segments. The sucrase/isomaltase ratio was significantly greater in pancreatic duct-occluded animals than in controls in the two distal segments. Alkaline phosphatase activity was not affected by pancreatic duct occlusion. The greater relative increase of disaccharidase activities and sucrase/isomaltase activity ratios in the distal segments of duct-occluded animals, indicates a more important regulatory role of pancreatic enzymes in the distal small intestine. It is concluded that regulation of intestinal brush-border enzyme activity by pancreatic secretion is selective for enzyme and site as follows: disaccharidases, but not alkaline phosphatase, are regulated; the sucrase subunit of the sucrase/isomaltase complex is most sensitive to regulation, while lactase is least sensitive; and the regulatory effect on disaccharidases is greater in distal than in proximal intestine.     

Age-related changes in duodenal adaptation after distal small bowel resection in rat

Two groups of male Fisher 344 rats (young: 4 months old; aged: 25 months old) underwent either 70% distal small bowel resection or sham operation (small bowel transection). Rats from each treatment group of each age were sacrificed on the 10th (N=15: young rats;N=13: aged rats) or 20th (N=15: young;N=13: aged) postoperative day (POD), and the duodenal mucosa was weighed and assayed for DNA, RNA, and protein contents, as well as for specific activities of the disaccharidase, sucrase, maltase, and lactase. Compared to the sham operation, distal small bowel resection significantly increased DNA by 48%, RNA by 122%, and protein by 75% in young rats and DNA by 40%, RNA by 92%, and protein by 71% in aged rats on the 20th POD. Both young and aged rats showed similar adaptive hyperplasia on the 10th POD. On the 20th POD after distal small bowel resection, specific activities of all tested enzymes were significantly increased in young rats (sucrase +86%, maltase +110% and lactase +64%), but showed no significant changes in aged rats. These findings suggest that the duodenum of aged rats may have sufficient proliferative potential to respond to distal small bowel resection, but that the mechanisms governing return of function in response to distal small bowel resection are inhibited in aged rats, compared to those mechanisms in the young.Supported by grants from the National Institutes of Health (5R37 DK15241, P01 DK 35608).     

The Effects of Iron Deficiency, Protein Deficiency and Worm Infestation upon Disaccharidase Activity in the Rat

The effect of iron deficiency anaemia, protein deficiency and worm infestation upon intestinal disaccharidase activity in the rat was assessed following the observation that these factors may have contributed to the premature onset of lactase deficiency in man. Adaptation of intestinal lactase occurred between eight and ten weeks of age in young rats fed a 10% lactose diet. Iron deficiency anaemia depressed jejunal and ileal lactase activity. Sucrase and maltase activities were not significantly affected by iron deficiency. Adaptation of intestinal lactase was prevented by both protein deficiency and combined iron/protein deficiency. Sucrase activity was not significantly depressed by either of these and in many instances activity was higher than the control group. Similar changes were noted with maltase. Worm infestation with Nippostrongylus brasi-liensis consistently depressed jejunal lactase and maltase activities, but had little effect on sucrase activity. It was concluded that intestinal lactase in particular was depressed by a number of environmental factors and adaptation of lactase thereby prevented.     

Mucosal Enzyme Activity as a Quantitative Index of Early Functional Improvement in the Management of Coeliac Disease and Other Small Intestinal Diseases

Summary: The levels of alkaline phosphatase and the three disaccharidases, sucrase, lactase and maltase, have been measured in biopsy specimens from jejunal mucosa. Patients with small intestinal diseases have been compared with a control population consisting of patients and volunteer subjects. This quantitative index of mucosal function has been used to assess the early response to specific therapy of small intestinal diseases, including coeliac disease, giardiasis and Whipple's disease.
Biopsies from 13 patients with untreated coeliac disease showed a marked reduction of all enzymes studied. In most of these patients the results were well outside the normal range. Lactase concentration was most severely reduced. In eleven patients studied following commencement of a gluten free diet, mucosal enzyme levels were significantly higher and frequently within the normal range. Lactase levels, although higher than in untreated patients, usually remained below normal values.
In eight patients with coeliac disease, mucosal biopsies were compared before and after commencement of a gluten free diet. The repeat biopsies were taken as early as six weeks following commencement of treatment. In all patients mucosal enzyme levels were significantly increased although histological changes were frequently difficult to recognize.     

Persistent Mucosal Abnormalities in Coeliac Disease Are Not Related to the Ingestion of Trace Amounts of Gluten

Background: It is expected that in patients with coeliac disease the small-bowel mucosal mucosa will return to normal if they adhere to a gluten-free diet (GFD). However, in many this is not the case. This study aims to determine whether this persistent villous atrophy (VA) could be due to continued ingestion of the trace amounts of gluten in `gluten-free' foods, as defined by the WHO/FAO Codex Alimentarius. Methods: Duodenal biopsy specimens from 89 adults with long-standing coeliac disease were examined, and the findings correlated with their form of gluten-free diet. Results: In 51 subjects the duodenal specimen was normal, whereas in 38 there was villous atrophy (partial, 28; subtotal, 8; total, 2). There was no relationship between the presence or absence of VA and ingestion of either a GFD as defined by the Codex Alimentarius (Codex-GFD; 39 patients) or a GFD that contained no detectable gluten (NDG diet; 50 patients). Intraepithelial lymphocyte counts were higher, and lactase levels lower, in subjects with an abnormal biopsy specimen than in those in whom it was normal. However, within each of these biopsy groups there was no difference in these variables between patients on a Codex-GFD and those on an NDG-GFD. IgA antigliadin antibody was detected in 4 of 29 patients on a Codex-GFD and in 3 of 13 on a NDG-GFD (NS). Conclusion: The persistent mucosal abnormalities seen in patients with coeliac disease on a GFD are not due to the ingestion of trace amounts of gluten. The consequences of these abnormalities have yet to be determined.