Intestinal lactase, sucrase and alkaline phosphatase in relation to age, sex and site of intestinal biopsy in 477 Irish subjects

Relationships of Intestinal Lactase and the Small Intestinal Microbiome with Symptoms of Lactose Intolerance and Intake in Adults

BACKGROUND

Approximately two-thirds of adults are genetically predisposed to decreased lactase activity after weaning, putting them at risk of lactose intolerance. However, symptoms are a poor marker of lactose maldigestion.

AIMS

We assessed association between self-reported lactose intolerance and intestinal lactase, lactose intake, and the small intestinal microbiome.

METHODS

Patients 18-75 years presenting for upper endoscopy were recruited prospectively. Observational study participants completed a lactose intolerance symptom questionnaire and reported lactose intake. Post-bulbar biopsies were obtained to measure lactase activity and assess the small intestinal mucosal microbiome. We compared intestinal lactase between patients with and without lactose intolerance. We assessed associations between lactose intolerance symptoms and lactase and lactose intake. We examined associations of small bowel microbial composition with self-reported lactose intolerance and symptoms.

RESULTS

Among 34 patients, 23 (68%) reported lactose intolerance. Those with lactose intolerance had higher total symptom scores, more frequent bowel urgency, and more bowel movements after consuming dairy. The proportion of individuals with abnormal lactase activity did not differ by lactose intolerance status. Median lactase levels were correlated with total lactose intolerance symptom scores (p = 0.038) and frequency of bowel urgency (p = 0.012). Daily lactose intake did not differ between groups. In 19 patients, we observed significant associations of small intestinal microbiome beta diversity with stool consistency after consuming dairy (p = 0.03).

CONCLUSIONS

Intestinal lactase is associated with lactose intolerance symptoms and bowel urgency in adults but does not distinguish the clinical phenotype entirely. Studying other contributing factors (microbiota, diet) may further clarify the pathophysiology of lactose intolerance.

The genetically programmed down-regulation of lactase in children

BACKGROUND & AIMS

Intestinal lactase activity is high in all healthy human babies, but in adults a genetic polymorphism, which acts in cis to the lactase gene, determines high or low messenger RNA (mRNA) expression and activity (lactase persistence and nonpersistence, respectively). Our aim was to investigate the onset of expression of this polymorphism in children.

METHODS

Activities were analyzed in relation to age in normal biopsy specimens from a 20-year collection of diagnostic specimens. In a smaller set of 32 samples, aged 2-132 months, RNA was extracted for semiquantitative reverse-transcription polymerase chain reaction. Marker polymorphisms were used to determine the allelic origin of lactase mRNA transcripts.

RESULTS

Analysis of 866 children showed evidence that the lactase persistence/nonpersistence polymorphism began before 5 years of age. The 32 children tested had high lactase mRNA and activity. Six children aged 2-16 months showed equal expression of two alleles, 2 children aged 7 and 14 months showed slightly asymmetric expression, and 7 children aged 22-132 months showed very asymmetric expression, the second allele being undetectable in the 11-year-old, as previously seen in lactase-persistent heterozygote adults.

CONCLUSIONS

Genetically programmed down-regulation of the lactase gene is detectable in children from the second year of life, although the onset and extent are somewhat variable.

Abnormal pancreolauryl tests in coeliac disease: lack of correlation with the degree of intestinal mucosal damage

AIMS

To determine the frequency of abnormal pancreolauryl tests in untreated and treated adults with coeliac disease and to see whether abnormalities in treated coeliac patients correlate with the degree of recovery of intestinal morphology or brush border enzyme activity.

METHODS

Pancreolauryl tests were performed in a study population of 57 adult coeliac patients (25 on gluten containing diets and 32 on gluten free diets), 59 symptomatic controls, and eight patients with pancreatic disease. Brush border enzyme activity and morphological assessment were performed on small intestinal biopsies in 27 of the treated coeliac patients.

RESULTS

Forty per cent of untreated coeliac patients and 18% of treated coeliac patients had abnormal tests. In treated coeliac patients, no significant correlation was detected between the pancreolauryl test result and either brush border enzyme activity or morphological parameters.

CONCLUSION

Abnormal pancreolauryl test results are common in untreated and treated adult coeliac disease patients. Abnormalities in treated coeliac patients do not correlate with the degree of recovery of small intestinal morphology or brush border enzymes.

Celiac sprue and immunodeficiency states: a 25-year review

Immunoglobulin deficiency, especially deficiency of IgA, has been described in patients with celiac sprue (CS). Our study was performed in an area of high prevalence of CS to determine the prevalence of immunodeficiency states in patients with CS, to examine their clinical characteristics, response to treatment, and HLA phenotypes compared with a group of age- and sex-matched persons with CS but without immunoglobulin deficiency. Fourteen of 604 patients with CS were identified as being selectively deficient in IgA, whereas one had common variable immunodeficiency. At diagnosis, anemia was present in 8 of 14 IgA-deficient patients compared with 10 of 42 controls (p = 0.047), whereas abdominal pain was more common in controls with CS. Autoimmunity and recurrent infection were more prevalent in the IgA-deficient group. Response to gluten-free diet was similar in both groups in terms of histologic structure and recovery of intestinal brush-border enzyme activity. IgA-deficient participants with CS had no increased risk of associated malignancy or lymphoma. HLA phenotypes were similar in both groups. The prevalences of selective IgA deficiency and common variable immunodeficiency in this series of patients with CS are 2.31 in 100 and 0.16 in 100, respectively. Although this group is unique in character, close follow-up coupled with conscientious compliance with a gluten-free diet, remains the mainstay of treatment for these patients.

Activity of duodenal disaccharidases in relation to normal and abnormal mucosal morphology

Endoscopic duodenal biopsy specimens from 100 predominantly adult Caucasian patients under investigation for gastrointestinal symptoms were used to establish reference ranges for lactase, sucrase, and maltase in the duodenum. Duodenal and jejunal disaccharidase values were compared and the association between disaccharidase activity and morphology in the duodenum was examined. Mean lactase activities were about 40% lower in the duodenum compared with the jejunum; maltase was reduced to a lesser extent; and sucrase activities were much the same in the two sites. Lactase deficiency was found in 24 patients of whom 14 (58%) had duodenal disease. The presence of moderate to severe duodenal lesions was associated with a significant decrease in all disaccharidase activities, while only lactase was reduced in mild lesions. Twelve patients had normal lactase activity, despite the presence of duodenal disease. It is concluded that specific reference ranges for duodenal mucosal disaccharidase activity are required as this is less than that of jejunum. Reduced duodenal disaccharidase activity is usually but not invariably associated with morphological abnormality.

Brush border enzymes in coeliac disease: histochemical evaluation

Two hundred and ninety four duodenal and jejunal mucosal biopsy specimens from patients with coeliac disease, treated and untreated, and other conditions were examined histologically and by histochemical staining for five peptidase and three disaccharidase enzymes to determine profiles of activity. Suppression of activity paralleled the histology with the following enzymes: lactase, trehalase, brush border endopeptidase, dipeptidyl peptidase II and isomaltase. Lactase, trehalase, and brush border endopeptidase were specifically suppressed in untreated coeliac disease and were diagnostically useful. Examination of a combination of enzymes is recommended.

Compliance with gluten free diet in coeliac disease

Fifty two children in whom coeliac disease was confirmed by persistent enteropathy while they were taking gluten were monitored to assess the effects of compliance with a gluten free diet (GFD). Between the ages of 17.8 and 18.5 years height (in 45 patients followed up for a mean of 14.9 years) and weight (in 43 followed up for a mean of 15.2 years) were significantly lower in those complying poorly with a GFD compared with those complying well. Of the 37 patients still attending the clinic after a mean of 25 years, having been followed up for a mean of 18.4 years, 16 who had complied well with the diet had normal or only slightly abnormal mucosal morphology whereas all 10 who had not complied had abnormal morphology. In these 10 lactase, sucrase, and alkaline phosphatase activities were significantly less than values in those who complied well. Mucosal sucrase and alkaline phosphatase activities in those who complied well were no different from those in a control population, whereas lactase activity was significantly lower. It is concluded that failure to comply with a GFD during childhood results in decreased adult stature and in persisting active enteropathy with depressed brush border enzyme activity.

Influence of remote cancer and obesity on, and distribution of mucosal enzymes in, the upper small intestine

A series of mucosal enzymes were estimated by analysis of homogenized biopsy specimens from the lower duodenal flexure, obtained from 10 large-bowel carcinoma patients, 15 patients with morbid obesity, and 15 controls. In 11 subjects the distribution along the upper small intestine was determined. The activities of the brush border enzymes lactase (p less than 0.01), neutral-alpha-glucosidase (p less than 0.01), and alkaline phosphatase (p less than 0.05) were significantly lower in the large-bowel carcinoma patients than in the controls. In obese subjects significantly lower activities (p less than 0.05) were demonstrated for the basolateral membrane enzyme 5'-nucleotidase and the lysosomal enzymes N-acetyl-beta-D-glucosaminidase and acid beta-glucuronidase, when compared with those in controls. Compared with the enzyme levels of the duodenal bulb, significantly higher activities of a series of enzymes were demonstrated at both the lower duodenal flexure and the angle of Treitz.

Decreased brush border hydrolase activities without gross morphologic changes in human intestinal mucosa after prolonged total parenteral nutrition of adults

Animal experimentation with total parenteral nutrition (TPN) has revealed the occurrence of atrophy of the intestinal mucosa and decreased enzyme activities of the brush border, notably the disaccharidases. These findings have heretofore not been confirmed in human investigation. We performed endoscopic biopsies in the third part of the duodenum in 7 adults before TPN, after 21 days of TPN, and after a progressive oral refeeding. We noted a clear-cut decrease of major enzyme activities during TPN (sucrase, maltase, lactase, glucoamylase, acid aminopeptidase, dipeptidyl peptidase) without any morphologic modifications as observed with standard histology. Electron microscopy showed a slight but significant decrease in the height of microvilli. The decreased enzyme activities were rapidly restored after oral refeeding. Thus, the functional consequences of the modifications observed during medium-term TPN in adults are probably limited.

Selective expression of brush border hydrolases by mouse Peyer's patch and jejunal villus enterocytes

Developmental profiles describing the expression of lactase, alpha-glucosidase, and alkaline phosphatase activities have been determined quantitatively in mouse jejunal enterocytes during migration over villi and Peyer's patch lymphoid tissue. The predicted maximal lactase and alpha-glucosidase activities expressed by enterocytes migrating over Peyer's patch follicles were about one-quarter and one-half of values found in control villi. Alkaline phosphatase activity was, on the other hand, one third greater in Peyer's patch compared with villus enterocytes. Expression of lactase and alpha-glucosidase activities was initially less in enterocytes migrating along interfollicular compared with control villi. Subsequent increase in hydrolase activities occurred during the later stages of enterocyte migration over interfollicular villi. Lactase activity in athymic mice Peyer's patch enterocytes was identical to that recorded for control mice. The corresponding value for villus lactase was, however, only half that found in control tissue. Factors produced locally in lymphoid follicles are probably responsible for selective effects on enterocyte differentiation.

Intestinal lactase, sucrase, and alkaline phosphatase in 373 patients with coeliac disease

Lactase, sucrase, and alkaline phosphatase activities were measured in 833 peroral small intestinal biopsies from 373 patients with coeliac disease. Enzyme activities decreased with increasing degrees of mucosal damage. Enzyme activities in mucosae of patients with coeliac disease in remission were lower than in control groups matched for age, sex, and site of biopsy. Enzyme activities were measured in 81 patients when the mucosa was severely damaged and later when considerable improvement had occurred. Lactase activity remained low in 13% of patients under the age of 18 and in 33% of those over 18 years. Sucrase activity usually improved with histological recovery, but alkaline phosphatase activity tended to remain depressed in patients in whom lactase activity failed to improve.