Role of Circulating Peptide YY in the Inhibition of Gastric Acid Secretion by Dietary Fat in Humans

Objectives. Xylose absorption testing has traditionally involved measurement of serum xylose and/or measurement of excreted xylose in urine. However, by enriching xylose with a ¹³C- or ¹⁴C-isotope, absorption of an oral xylose load will be reflected in the time-dependent pattern of ¹³CO₂ or ¹⁴CO₂ exhaled in breath. Our objectives were to evaluate the diagnostic properties of ¹³C-xylose and ¹⁴C-xylose breath tests in coeliac disease, and to develop a diagnostic breath test index. Material andmethods. We reviewed data from 41 coeliac patients who underwent the ¹⁴C-xylose breath test before and after commencement of a gluten-free diet, and 60 coeliac patients who underwent the ¹³C-xylose breath test, 37 of whom repeated the test after starting a gluten-free diet. Coeliac patients were compared with healthy control subjects. Results. Coeliac patients exhaled significantly less ¹³CO₂ or ¹⁴CO₂ than healthy controls during the first hour of the test and more isotope-labelled CO₂ than control subjects after 3 h. Diagnostic accuracy was optimal with test duration of 210 min combining gas measurements at 30 min and 210 min in a simple fraction. This gas fraction index (30 min/210 min) distinguished between coeliac patients and healthy control subjects with 84–95% sensitivity and 87–94% specificity. After commencement of a gluten-free diet, the gas fraction index increased in most coeliac patients, but remained lower than that in healthy control subjects. Conclusions.¹³C-xylose- and ¹⁴C-xylose breath tests discriminate between coeliac patients and healthy control subjects with high sensitivity and specificity. The stable isotope ¹³C-xylose breath test has comparable diagnostic accuracy to the radioactive isotope ¹⁴C-xylose breath test and should be the preferred alternative to traditional xylose absorption tests.     

Absorption of Inorganic and Haemoglobin Iron in Coeliac Disease

Absorption from a 5 mg dose of iron as Fe++ or haemoglobin iron was studied using a Total Body Counter in control subjects and patients with coeliac disease. In both groups the majority of subjects were iron deficient. Thirteen control subjects, 13 patients with untreated coeliac disease and 14 on treatment with gluten-free diet had both absorption tests. Absorption of Fe++ iron was reduced in untreated coeliac disease. This was particularly significant in iron deficient patients. Absorption was improved on treatment with gluten-free diet; In contrast, the absorption of haemoglobin iron was not affected in coeliac disease, indicating that absorption of iron in this form is not dependent on the integrity of the mucosa of the proximal small bowel.     

The diagnosis of small bowel bacterial overgrowth in elderly patients.

OBJECTIVE: To examine the frequency of small bowel bacterial overgrowth in elderly subjects. DESIGN: Prospective observational study. SETTING: Department of Health Care of the Elderly in a university teaching hospital. PATIENTS: Thirteen elderly control subjects having undergone normal gastroscopy with normal hematology and anthropometry; 39 consecutive referrals of elderly patients with clinical or biochemical evidence of malnutrition. MAIN OUTCOME MEASURES: Duodenal bacterial counts and the 14C-glycocholate, hydrogen, and 14C-xylose breath tests. RESULTS: Five of the 13 control subjects and 21 of 39 patients with malnutrition had high duodenal bacterial counts (greater than 10(5) organisms/mL), whereas only seven patients were judged to have clinically significant bacterial overgrowth. The 14C-xylose breath test showed a high specificity (89%) but a low sensitivity (30%) when compared with the results of duodenal culture. The hydrogen breath tests and the 14C-glycocholate test showed a similar picture of moderately high specificity and low sensitivity (77% and 20%, respectively, for the hydrogen breath test, 76% and 33%, respectively, for the 14C-glycocholate test). CONCLUSIONS: A positive xylose breath test was the best predictor of high duodenal bacterial counts. However, since many elderly subjects have high duodenal bacterial counts, the overdiagnosis of bacterial overgrowth syndrome will result if duodenal culture is relied upon exclusively.     

Splanchnic haemodynamics in patients with coeliac disease: effects of a gluten-free diet

BACKGROUND: Coeliac disease is characterized by structural and functional changes in the small bowel which may also result in haemodynamic changes. AIMS: To establish whether splanchnic haemodynamics can be modified by a gluten-free diet. PATIENTS: Ten coeliac patients and 10 paired healthy subjects. METHODS: Echo-Doppler measurements were made of splanchnic vessels both fasting and after a standard meal before and after 9 months of a gluten-free diet. RESULTS: In comparison to controls, coeliac patients had higher superior mesenteric artery blood velocity and flow, with lower resistance indexes and higher portal vein velocity and flow, particularly 3 h after a meal. Postprandial hyperaemia was reduced and delayed in time. Intrasplenic resistance indexes were also significantly lower both fasting and after a meal. After 9 months of a gluten-free diet, no significant differences were observed between coeliac patients and controls, both fasting and after a meal. CONCLUSIONS: Splanchnic haemodynamics is significantly changed in coeliac patients, mainly after a meal. On treatment with a gluten-free diet, both fasting and postprandial haemodynamics became normal.     

Coeliac disease: Oral ulcer prevalence, assessment of risk and association with gluten-free diet in children

AIMS: Oral mucosal lesions may be markers of chronic gastrointestinal disorders, such as those causing malabsorption. Our objectives were to assess the prevalence of recurrent oral aphthous-like ulcers in coeliac disease patients living in the Mediterranean area, and to evaluate the impact of a gluten-free diet. METHODS: A test group of 269 patients (age range 3-17 years) with coeliac disease confirmed both serologically and histologically was compared with a control group of 575 otherwise clinically healthy subjects for the presence, or a positive history of aphthous-like ulcers. Coeliac disease patients with aphthous-like ulcers were re-evaluated 1-year after starting a gluten-free diet. RESULTS: Aphthous-like ulcers were found significantly more frequently in coeliac disease, in 22.7% (61/269) of patients with coeliac disease versus 7.1% (41/575) of controls (p=<0.0001; chi-square=41.687; odds ratio=4.3123; 95% confidence interval=2.7664:6.722). Most coeliac disease patients with aphthous-like ulcers and adhering strictly to gluten-free diet (71.7%; 33/46) reported significant improvement on gluten-free diet, with no or reduced episodes of aphthous-like ulcers (p=0.0003; chi-square=13.101; odds ratio=24.67; 95% confidence interval=2.63:231.441). CONCLUSIONS: The epidemiological association found between coeliac disease and aphthous-like ulcers suggests that recurrent aphthous-like ulcers should be considered a risk indicator for coeliac disease, and that gluten-free diet leads to ulcer amelioration.     

Comparison of the 1-gram [14C]xylose, 10-gram lactulose-H2, and 80-gram glucose-H2 breath tests in patients with small intestine bacterial overgrowth

The sensitivity of three breath tests (1-g [14C]xylose, 10-g lactulose-H2, and 80-g glucose-H2) was studied in 20 subjects with culture-documented small intestine bacterial overgrowth. Elevated breath 14CO2 levels were seen within 30 min of [14C]xylose administration in 19 of 20 subjects with bacterial overgrowth and 0 of 10 controls. In contrast, H2 breath tests demonstrated uninterpretable tests (absence of H2-generating bacteria) in 2 of 20 subjects with bacterial overgrowth and 1 of 10 controls and nondiagnostic increases in H2 production in 3 of 18 glucose-H2 and 7 of 18 lactulose-H2 breath tests in subjects with bacterial overgrowth. These findings demonstrate continued excellent reliability of the 1-g [14C]xylose breath test as a diagnostic test for bacterial overgrowth, indicate inadequate sensitivity of H2 breath tests in detecting bacterial overgrowth, and suggest the need for evaluation of a 13CO2 breath test having the same characteristics as the [14C]xylose test (avidly absorbed substrate having minimal contact with the colonic flora) for nonradioactive breath detection of bacterial overgrowth in children and reproductive-age women.     

Celiac disease: clinical and subclinical forms

Coeliac disease is an intolerance to gluten that classically produces a chronic diarrhoea with a picture of malabsorption and a total villous atrophy. These elements regress completely in a sequential way under a prolonged strict gluten-free diet. The progress registered in the understanding of this affection depends on the individualization of the atypical forms (delayed isolated stature, constipation...) of asymptomatic forms thanks to the study of specific antibodies (anti-gliadin, anti-endomysium, and more recently anti-transglutaminase). The auto-immune nature of coeliac disease is well established. The diagnostic criteria are simplified allowing the commencement of a gluten-free diet which must be perfectly detailed. Finally, allergy to wheat flour merits individualization in the framework of coeliac disease (cf. article).     

Cholesteryl octanoate breath test. Preliminary studies on a new noninvasive test of human pancreatic exocrine function

A new breath test for noninvasive assessment of pancreatic exocrine function in humans was developed. The test is based on the hydrolysis of cholesteryl-[1-14C]octanoate by pancreatic carboxyl ester lipase (cholesterol esterase) with subsequent absorption and hepatic metabolism of the liberated octanoate to 14CO2. The rate at which 14CO2 appears in breath appeared to be proportional to the rate of hydrolysis. The substrate is administered as a gum acacia stabilized emulsion of vegetable oil (18 g) containing cholesteryl octanoate (2 g; 4.4 microCi) dispersed in a 500-ml isotonic meal. Tests were performed in 6 healthy volunteers and 11 patients with pancreatic disease with varying degrees of steatorrhea. In healthy subjects, 14CO2 output was rapid with peak output occurring at 60-90 min in all subjects; cumulative output in 4 h averaged 30%. Duplicate studies indicated that the time-course of 14CO2 recovery was reproducible. The pattern of 14CO2 output in patients with pancreatic disease varied widely. Patients without steatorrhea (fecal fat less than or equal to 7 g/day) or with mild steatorrhea (fecal fat 7-11 g/day) had normal or near normal patterns of 14CO2 output, whereas patients with moderate or severe steatorrhea (fecal fat greater than 11 g/day) expired 14CO2 at a rate one-third to one-tenth that of the healthy volunteers. Addition of pancreatic enzyme supplementation to the test meal increased 14CO2 output in 6 of 6 patients with moderate or severe steatorrhea, suggesting that the activity of pancreatic carboxyl ester lipase was rate limiting in these patients. In an additional study in a healthy volunteer, 14CO2 and 13CO2 were measured simultaneously in breath after ingestion of a test meal containing cholesteryl-[1-13C]octanoate and 14C-octanoate. 14CO2 was expired more rapidly than 13CO2, suggesting that hydrolysis of the substrate may also be rate limiting in healthy volunteers. These studies indicate that severe pancreatic exocrine dysfunction can be detected with a simple breath test in 60-90 min.     

Coeliac disease and hearing loss: preliminary data on a new possible association

OBJECTIVE: Coeliac disease (CD), an autoimmune gluten-dependent enteropathy, can be associated with several extra-intestinal manifestations, including neurological disorders. At present, no data are available on the presence of hearing loss disorder in coeliac patients. The aim of the present study was to investigate the prevalence of hearing loss in coeliac patients compared with that in healthy controls. MATERIAL AND METHODS: Twenty-four adult coeliac patients and 24 healthy subjects matched for gender, age, smoking and drinking habits were enrolled in the study. Among the coeliac patients, 6 were newly diagnosed and 18 patients were on a gluten-free diet for at least one year. RESULTS: A hearing loss was found in 10 (47.1%) coeliac patients and 2 (9.1%) healthy controls. All CD patients with hearing loss presented a sensorineural hearing loss. The prevalence of hearing loss was significantly higher in coeliac patients than in healthy controls (p = 0.01) but it was not significantly different between untreated (33.3%) and treated (44.4%) coeliac patients (p: NS). CONCLUSIONS: Despite the low number of subjects evaluated, the present study showed a higher prevalence of hearing loss in coeliac patients than in healthy controls, suggesting an association between CD and hearing loss. Immunological processes such as ear-specific and non-specific autoantibodies and vasculitis could be the basis of this association. Further longitudinal investigations on a larger sample size will be necessary to confirm the present data.     

Regression of lactose malabsorption in coeliac patients after receiving a gluten-free diet

OBJECTIVE: In a recent study by our group, it was shown that a large proportion of patients with lactose malabsorption and with no bacterial overgrowth are affected by silent coeliac disease (CD). Our aim was to evaluate the effect of a gluten-free diet on lactose malabsorption assessed using the hydrogen lactose breath test (LBT) and also the relationship with normalization of duodenal biopsies in coeliac patients. MATERIAL AND METHODS: Fifteen patients (11 F, 4 M; mean age 35.8+/-6) affected by CD with a positive LBT and negative glucose breath test were enrolled. All were started on a gluten-free diet and were re-evaluated after 6 months by LBT and after 12 months by both LBT and upper gastrointestinal endoscopy with biopsies. RESULTS: LBT normalization was observed in 1 out of 15 patients (6.7%) after 6 months and in 9 of the remaining 14 (64.2%) after 12 months. Duodenal biopsies showed normal villi in 8 patients, partial villous atrophy in 5 and total atrophy in 2. CONCLUSIONS: The present study shows that a large proportion of CD patients experience a regression of lactose malabsorption after receiving a gluten-free diet. This may be related to normalization of the brush border with an improvement of lactase enzyme activity. LBT should be performed after 12 months in CD patients on a gluten-free diet in order to assess the persistence/disappearance of lactose malabsorption, thus avoiding an unnecessary lactose-free diet.     

Assessment of autonomic function in untreated adult coeliac disease

AIM: Some recent studies showed that alteration of upper-gut motility in coeliac disease may be related to dysfunction of autonomic nervous system. The aim of our study was to investigate whether autonomic nervous system was altered in untreated and unselected coeliac disease patients. METHODS: We studied 8 untreated and consecutive coeliac disease patients (2 males and 6 females, age range 37+/-14.5 years). Histological evaluation of duodenal mucosa, anti-gliadin antibodies (AGA), antiendomysial antibodies (EMA) and anti-tTG antibodies and sorbitol H2 breath test were performed in all patients. Extrinsic autonomic neuropathy was assessed by the standardized measurement of cardiovascular reflexes (lying-to-standing, Valsalva manoeuvre, deep breathing, sustained handgrip). The results obtained were compared with a healthy, asymptomatic control group (6 males and 7 females, age range 42.3+/-13.5 years). RESULTS: Coeliac patients exhibited a lower increase of PAS as a response to isometric effort, a reduction of spectral power LF as a response to clinostatic position, but without statistical significance. Also they showed a lower tolerance to orthostatic position, associated with a latent disequilibrium of sympathetic-vagal balance, a relative prevalence of parasympathetic component of the autonomic function. However, these results were not statistically significant when compared with control group (P = n.s.). And they were unchanged after 6 and 12 mo of gluten-free diet. CONCLUSION: This study failed to confirm a significant correlation between autonomic dysfunction and coeliac disease, yet we could not exclude a role of autonomic dysfunction in the genesis of systemic symptoms in some coeliacs.     

Altered small-bowel mucosal vascular network in untreated coeliac disease

Objective. It has recently been shown that serum autoantibodies targeted against transglutaminase 2 derived from untreated coeliac patients can disturb several steps of angiogenesis in vitro. The purpose of this study was to establish whether the small-bowel mucosal vasculature is altered in coeliac disease and whether the putative changes are gluten dependent. Material and methods. The small-bowel mucosal microvessel architecture was examined in duodenal biopsy samples from coeliac patients before and after a gluten-free diet and from non-coeliac controls. In addition, the vasculature was subjected to a detailed morphometric analysis. Double immunofluorescent stainings of the vasculature with anti- α-smooth muscle actin antibody were performed in order to assess the maturity of mucosal vessels. Coeliac disease-specific transglutaminase 2-targeted autoantibody deposits in the vessel wall were studied using triple immunofluorescent stainings. Results. On a gluten-containing diet the mucosal vasculature in the small intestine of untreated coeliac disease patients was altered in overall organization as well as in the number and maturity of the vessels when compared to healthy subjects. In patients on a gluten-free diet, the vasculature normalized parallel to mucosal recovery. Conclusions. In coeliac disease, ingestion of gluten leads to altered appearance of small-bowel mucosal microvasculature. It is thus conceivable that the small-bowel mucosal vascular biology might be involved in the pathogenesis of coeliac disease.     

Cell-mediated immunity to gluten within the small intestinal mucosa in coeliac disease.

Jejunal biopsies from controls and coeliac patients were maintained in organ culture in the presence of gluten fraction III. The culture media were assayed for evidence of lymphokine activity in a migration inhibition test using normal peripheral blood leucocytes. Significant inhibition of migration was produced by media from untreated coeliac patients compared with controls (P less than 0.005) or treated coeliac patients (P less than 0.001), indicating the production of a leucocyte migration inhibition factor (LIF) by untreated coeliac mucosa in response to gluten fraction III. The degree of inhibition correlated with the preculture interepithelial lymphocyte count in the coeliac biopsies (P less than 0.02). In six coeliac patients studied when on a normal diet and on a gluten-free diet, LIF was produced while on a normal diet, but not while on a gluten-free diet. These results suggest that a local cell-mediated immune reaction to gluten is present in the mucosa of patients with untreated coeliac disease but that this is reversed by treatment with a gluten-free diet.     

A major step towards a practical and meaningful gluten analysis

Coeliac disease is triggered by the cereal protein gluten. Elimination of gluten is the effective therapy. To increase food safety for coeliac patients, gluten has been included in food regulations introducing obligatory labelling. These regulations depend upon effective analytical control. A combined system using cocktail extraction and the R5 enzyme-linked immunosorbent assay has now been described for gluten analysis, which shows good performance. Every effort should be made to keep the diet of coeliac patients as gluten-free as possible.     

Gastrointestinal Symptoms Rating Scale in Coeliac Disease Patients on Wheat Starch-based Gluten-free Diets

Background: A wheat starch-based gluten-free diet is widely adopted in the treatment of coeliac disease, even though the products contain trace amounts of gluten. The aim here was to establish whether such a diet sustains abdominal symptoms. Methods: The Gastrointestinal Symptom Rating Scale (GSRS) was applied to 58 coeliac disease patients on gluten-free diets and 110 non-coeliac controls. An estimate was made of daily dietary fibre and wheat starch-derived gluten. Psychological well-being was evaluated by a structured interview. Twenty-three coeliac patients consented to small-bowel biopsy. Results: The mean GSRS score in coeliac disease patients did not differ from that in control subjects. Poorer psychological well-being was associated with abdominal symptoms in coeliac patients, whereas the daily amount of wheat starch had no effect on GSRS score. Overall dietary compliance was good, and villous atrophy was found in only 2 out of 23 patients. The average fibre consumption, 13 g per day, was lower than recommended. Conclusions: Wheat starch-based gluten-free products are well-tolerated in coeliac disease patients, provided that their diets are otherwise strict.     

Infliximab in refractory coeliac disease

Coeliac disease is generally well controlled with gluten-free diet but a small proportion of patients require corticosteroids or immunomodulatory agents. Response to anti-tumour necrosis factor (anti-TNF) agents raises interesting questions about both the pathogenesis of coeliac disease and the mechanism of action of anti-TNF agents. Refractory coeliac disease poses a therapeutic challenge to clinicians and carefully selected patients may benefit from anti-TNF therapy.     

Atypical coeliac disease found with serologic screening

Eighteen patients with coeliac disease were found by screening for reticulin antibodies of unselected sera at the time when determination of various tissue antibodies was requested. Joint disease, allergic and pulmonary disorders, and diabetes were particularly observed. IgA class reticulin antibody, in particular, proved to be specific for coeliac disease. Most patients with coeliac disease also had positive serum gliadin antibodies. Abdominal symptoms and signs of malabsorption were slight and infrequent. In most patients a gluten-free diet resulted in the improvement of jejunal mucosal histology, and serum reticulum and gliadin antibody titres decreased simultaneously, reflecting the appropriateness of the diet. Coeliac disease often has mild and atypical symptoms, and, particularly in certain disease groups, screening with reticulin antibody test seems to be appropriate.     

Atypical Coeliac Disease Found with Serologic Screening

Eighteen patients with coeliac disease were found by screening for reticulin antibodies of unselected sera at the time when determination of various tissue antibodies was requested. Joint disease, allergic and pulmonary disorders, and diabetes were particularly observed. IgA class reticulin antibody, in particular, proved to be specific for coeliac disease. Most patients with coeliac disease also had positive serum gliadin antibodies. Abdominal symptoms and signs of malabsorption were slight and infrequent. In most patients a gluten-free diet resulted in the improvement of jenunal mucosal histology, and serum reticulum and gliadin antibody titres decreased simultaneously, reflecting the appropriateness of the diet. Coeliac disease often has mild and atypical symptoms, and, particularly in certain disease groups, screening with reticulin antibody test seems to be appropriate.     

Gastrointestinal symptoms rating scale in coeliac disease patients on wheat starch-based gluten-free diets

BACKGROUND: A wheat starch-based gluten-free diet is widely adopted in the treatment of coeliac disease, even though the products contain trace amounts of gluten. The aim here was to establish whether such a diet sustains abdominal symptoms. METHODS: The Gastrointestinal Symptom Rating Scale (GSRS) was applied to 58 coeliac disease patients on gluten-free diets and 110 non-coeliac controls. An estimate was made of daily dietary fibre and wheat starch-derived gluten. Psychological well-being was evaluated by a structured interview. Twenty-three coeliac patients consented to small-bowel biopsy. RESULTS: The mean GSRS score in coeliac disease patients did not differ from that in control subjects. Poorer psychological well-being was associated with abdominal symptoms in coeliac patients, whereas the daily amount of wheat starch had no effect on GSRS score. Overall dietary compliance was good, and villous atrophy was found in only 2 out of 23 patients. The average fibre consumption, 13 g per day, was lower than recommended. CONCLUSIONS: Wheat starch-based gluten-free products are well-tolerated in coeliac disease patients, provided that their diets are otherwise strict.