Prolonged small-intestinal transit time in cystic fibrosis

A Gastroenterologist's Guide to Care Transitions in Cystic Fibrosis from Pediatrics to Adult Care

Cystic Fibrosis is a chronic disease affecting multiple systems, including the GI tract. Clinical manifestation in patients can start as early as infancy and vary across different age groups. With the advent of new, highly effective modulators, the life expectancy of PwCF has improved significantly. Various GI aspects of CF care, such as nutrition, are linked to an overall improvement in morbidity, lung function and the quality of life of PwCF. The variable clinical presentations and management of GI diseases in pediatrics and adults with CF should be recognized. Therefore, it is necessary to ensure efficient transfer of information between pediatric and adult providers for proper continuity of management and coordination of care at the time of transition. The transition of care is a challenging process for both patients and providers and currently there are no specific tools for GI providers to help ensure a smooth transition. In this review, we aim to highlight the crucial features of GI care at the time of transition and provide a checklist that can assist in ensuring an effective transition and ease the challenges associated with it.

Nutrition in children with exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency (EPI) is a condition defined as pancreatic loss of exocrine function, including decreased digestive enzymes and bicarbonate secretion, which leads to maldigestion and malabsorption of nutrients. It is a common complication in many pancreatic disorders. If left undiagnosed, EPI can cause poor digestion of food, chronic diarrhea, severe malnutrition and related complications. Nutritional status and fat-soluble vitamins should be carefully assessed and monitored in patients with EPI. Early diagnosis of EPI is clinically important for appropriate nutritional support and initiating pancreatic enzyme replacement therapy (PERT) which could significantly improve patient outcomes. The evaluation of nutritional status and related unique management in children with EPI will be discussed in this review.

Patient-specific in vitro drug release testing coupled with in silico PBPK modeling to forecast the in vivo performance of oral extended-release levodopa formulations in Parkinson's disease patients

Biorelevant in vitro release models are valuable analytical tools for oral drug development but often tailored to gastrointestinal conditions in 'average' healthy adults. However, predicting in vivo performance in individual patients whose gastrointestinal conditions do not match those of healthy adults would be of great value for optimizing oral drug therapy for such patients. This study focused on establishing patient-specific in vitro and in silico models to predict the in vivo performance of levodopa extended-release products in Parkinsońs disease patients. Current knowledge on gastrointestinal conditions in these patients was incorporated into model development. Relevant in vivo pharmacokinetic data and patient-specific in vitro release data from a novel in vitro test setup were integrated into patient-specific physiologically-based pharmacokinetic models. AUC, c_max and t_max of the computed plasma profiles were calculated using PK-Sim®. For the products studied, levodopa plasma concentration-time profiles modeled using this novel approach compared far better with published average plasma profiles in Parkinsońs disease patients than those derived from in vitro release data obtained from the 'average' healthy adult setup. Although further work is needed, results of this study highlight the importance of addressing patient-specific gastrointestinal conditions when aiming to predict drug release in such specific patient groups.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Review of Gastrointestinal Motility in Cystic Fibrosis

Gastrointestinal manifestations in patients with cystic fibrosis (CF) are extremely common and have recently become a research focus. Gastrointestinal (GI) dysfunction is poorly understood in the CF population, despite many speculations including the role of luminal pH, bacterial overgrowth, and abnormal microbiome. Nevertheless, dysmotility is emerging as a possible key player in CF intestinal symptoms. Our review article aims to explore the sequelae of defective cystic fibrosis transmembrane conductance regulator (CFTR) genes on the GI tract as studied in both animals and humans, describe various presentations of intestinal dysmotility in CF, review newer diagnostic motility techniques including intraluminal manometry, and review the current literature regarding the potential role of dysmotility in CF-related intestinal pathologies.

Gut reaction: impact of systemic diseases on gastrointestinal physiology and drug absorption

It was in 400 BC that Hippocrates reportedly stated that "death sits in the colon". The growth in our knowledge of the intestinal microbiome, the gut-brain axis and their function and imbalance has distinctly uncovered the complex relationship between the gut to disease predisposition and development, heralding the problem and the solution to disease pathology. Human studies of new drug molecules are typically performed in healthy volunteers and their specific disease indication. Approved drugs, however, are used by patients with diverse disease backgrounds. Here, we review the current literature of the gastrointestinal tract reacting to systemic disease pathology that elicits physiological and functional changes that consequently affect oral drug product performance.

Current and emerging comorbidities in cystic fibrosis

Cystic fibrosis transmembrane conductance regulator (CFTR) is expressed ubiquitously throughout the body. Thus, while respiratory manifestations dominate much of cystic fibrosis (CF) care, there are prominent multi-organ manifestations and comorbidities. In the general population, the number of comorbidities increases with aging. Few illnesses have experienced such a dramatic improvement in survival as CF, which has been transformed from an illness of childhood death to one of adult survival. Hence, as longevity increases in CF, it is paralleled by an increasing number of patients with multicomplex comorbidities availing of care from adult CF multi-disciplinary teams. This review gives an overview of the traditional CF associated comorbidities and those emerging in an aging adult cohort. While historically the treatment of CF focused on the consequences of CFTR dysfunction, the recent advent of CFTR modulators with the potential to enhance CFTR function represents an opportunity to potentially reverse or delay the development of some of the comorbidities associated with CF. Where evidence is available for the impact of CFTR modulatory therapy, namely ivacaftor on comorbidities in CF, this is highlighted.

Animal models of gastrointestinal and liver diseases. Animal models of cystic fibrosis: gastrointestinal, pancreatic, and hepatobiliary disease and pathophysiology

Multiple organ systems, including the gastrointestinal tract, pancreas, and hepatobiliary systems, are affected by cystic fibrosis (CF). Many of these changes begin early in life and are difficult to study in young CF patients. Recent development of novel CF animal models has expanded opportunities in the field to better understand CF pathogenesis and evaluate traditional and innovative therapeutics. In this review, we discuss manifestations of CF disease in gastrointestinal, pancreatic, and hepatobiliary systems of humans and animal models. We also compare the similarities and limitations of animal models and discuss future directions for modeling CF.

Cystic fibrosis and the role of gastrointestinal outcome measures in the new era of therapeutic CFTR modulation

With the development of new drugs that directly affect CFTR protein function, clinical trials are being designed or initiated for a growing number of patients with cystic fibrosis. The currently available and accepted clinical endpoints, FEV1 and BMI, have limitations. The aim of this report is to draw attention to the need and the ample possibilities for the development and validation of relevant gastrointestinal clinical endpoints for scientific evaluation of CFTR modulation treatment, particularly in young children and infants. The gastrointestinal tract offers very good opportunities to measure CFTR protein function and systematically evaluate CF related clinical outcomes based on the principal clinical gastrointestinal manifestations of CF: intestinal pH, intestinal transit time, intestinal bile salt malabsorption, intestinal inflammation, exocrine pancreatic function and intestinal fat malabsorption. We present a descriptive analysis of a variety of gastrointestinal outcome measures for clinical relevance, reliability, validity, responsiveness to interventions, feasibility in particular in young children and the availability of reference values.

Increased risk of colorectal neoplasia in adult patients with cystic fibrosis: a matched case-control study

OBJECTIVE

As the lifespan of patients with cystic fibrosis (CF) increases, concerns regarding the occurrence of bowel cancer have arisen. However, previous cohort studies have yielded contradictory results as to the risk of colorectal cancer (CRC) in the CF population. The aim of this study was to determine whether CF is associated with an increased risk of colorectal neoplasia.

METHODS

We performed a matched case-control study at a statewide CF center. Cases were adult CF patients undergoing colonoscopy in a 5-year period from 2007 to 2012. Controls were matched in a 2:1 ratio for age, gender, and colonoscopy indication.

RESULTS

A total of 50 patients with CF who underwent colonoscopy were identified. Among CF patients, there were 5 (10%) cases with CRC, 1 (2%) with ileal adenocarcinoma, 13 (26%) with adenomas, and 16(32%) with advanced adenomas. In contrast, there was 1 (1%) case with CRC, 11 (11%) with adenomas, and 6 (6%) with advanced adenomas identified among controls. Compared to controls, CF was associated with a 10-fold increased risk of CRC (odds ratio [OR] = 10.0, 95% confidence interval [CI]: 1.2-85.6; p = 0.03), threefold increased risk of adenomas (OR = 3.34, 95%CI: 1.23-9.08; p = 0.018], and sevenfold increased risk of advanced adenomas (OR = 6.95, 95% CI: 2.30-21.01; p = 0.001). Moreover, the quality of bowel preparation was significantly worse in CF patients with a fourfold (p = 0.01) increased likelihood of a poor preparation.

CONCLUSIONS

Our data suggest that CF patients are at significantly increased risk of CRC compared to age, sex, and colonoscopy-indication matched controls. Consideration should be given to the introduction of a CRC surveillance program in the CF population.

The cystic fibrosis intestine

The clinical manifestations of cystic fibrosis (CF) result from dysfunction of the cystic fibrosis transmembrane regulator protein (CFTR). The majority of people with CF have a limited life span as a consequence of CFTR dysfunction in the respiratory tract. However, CFTR dysfunction in the gastrointestinal (GI) tract occurs earlier in ontogeny and is present in all patients, regardless of genotype. The same pathophysiologic triad of obstruction, infection, and inflammation that causes disease in the airways also causes disease in the intestines. This article describes the effects of CFTR dysfunction on the intestinal tissues and the intraluminal environment. Mouse models of CF have greatly advanced our understanding of the GI manifestations of CF, which can be directly applied to understanding CF disease in humans.

Delayed small bowel transit in children with cystic fibrosis and pancreatic insufficiency

OBJECTIVE

Gastrointestinal disturbances are common in people with cystic fibrosis (CF); however, motility studies in this population have yielded inconsistent results. This study examined gastric emptying (GE) and small bowel transit (SBT) time in children with CF and pancreatic insufficiency compared with a healthy adult reference group.

METHODS

Participants consumed an 8-ounce liquid test meal (approximately 550 calories, 32 g of fat) labeled with 300 μCi 99m technetium (Tc) sulfur colloid. Subjects with CF received a standard dose of pancreatic enzymes before consuming the test meal. GE and SBT were measured using a standard nuclear medicine scan. GE was determined after correcting for 99mTc decay in both anterior and posterior images. SBT was determined by following the movement of the tracer from the stomach to the cecum. The percentage arrival of total small bowel activity at the terminal ileum and cecum/ascending colon at 6 hours was used as an index of SBT. A 1-way analysis of covariance was performed for comparisons between groups after adjustment for age, sex, and body mass index.

RESULTS

Subjects with CF (n = 16) had similar GE compared with the healthy reference group (n = 12); however, subjects with CF had significantly prolonged SBT time. At 6 hours, 37.2% ± 25.4% (95% CI 23.7-50.7) of the tracer reached the terminal ileum and colon compared with 68.6% ± 13.1% (95% CI 60.2-76.9) for the reference group (P < 0.001). After controlling for sex, age, and body mass index, this difference remained statistically significant (F = 12.06, adjusted R = 0.44, P < 0.002).

CONCLUSIONS

Children with CF and pancreatic insufficiency had unaltered GE but delayed SBT time when taking pancreatic enzymes.

Gastrointestinal transit times and motility in patients with cystic fibrosis

OBJECTIVE

Patients with cystic fibrosis (CF) often suffer from gastrointestinal (GI) dysfunction including obstructive symptoms, malabsorption and pain, but the underlying pathophysiology remains obscure.

AIM

To compare GI motility and transit times in CF patients and healthy controls.

MATERIAL AND METHODS

Ten CF patients (five women, median age 23) with pancreatic insufficiency were studied. Total gastrointestinal transit time (GITT) and segmental colonic transit times (SCTT) were assessed by radiopaque markers. Gastric emptying and small intestinal transit were evaluated using the magnet-based motility tracking system (MTS-1). With each method patients were compared with 16 healthy controls.

RESULTS

Basic contraction frequencies of the stomach and small intestine were normal, but the pill reached the cecum after 7 h in only 20% of CF patients while in 88% of controls (p = 0.001). Paradoxically, velocity of the magnetic pill through the upper small intestine tended to be faster in CF patients (median 1.1 cm/min, range 0.7-1.7) compared with controls (median 1.0 cm/min, range 0.6-1.7) (p = 0.09). No statistically significant differences were found in median gastric emptying time (CF: 58 min, range 6-107 vs. healthy: 41 min, range 4-125 (p = 0.24)), GITT (CF: 2 days, range 0.5-3.3 vs. healthy: 1.5 days, range 0.7-2.5 (p = 0.10)), right SCTT (CF: 0.5 day, range 0-1.1 vs. healthy: 0.4 day, range 0-1.0 (p = 0.85)), or left SCTT (CF: 1.0 day, range 0-2.2 vs. healthy 0.6 day, range 0.2-1.2 (p = 0.10)).

CONCLUSIONS

In spite of normal contraction patterns, overall passage through the small intestine is significantly delayed in CF patients while upper small intestinal transit may be abnormally fast.

Intestinal obstruction syndromes in cystic fibrosis: meconium ileus, distal intestinal obstruction syndrome, and constipation

Meconium ileus at birth, distal intestinal obstruction syndrome (DIOS), and constipation are an interrelated group of intestinal obstruction syndromes with a variable severity of obstruction that occurs in cystic fibrosis patients. Long-term follow-up studies show that today meconium ileus is not a risk factor for impaired nutritional status, pulmonary function, or survival. DIOS and constipation are frequently seen in cystic fibrosis patients, especially later in life; genetic, dietary, and other associations have been explored. Diagnosis of DIOS is based on suggestive symptoms, with a right lower quadrant mass confirmed on abdominal radiography, whereas symptoms of constipation are milder and of longer standing. In DIOS, early aggressive laxative treatment with oral laxatives (polyethylene glycol) or intestinal lavage with balanced osmotic electrolyte solution and rehydration is required, which now makes the need for surgical interventions rare. Constipation can generally be well controlled with polyethylene glycol maintenance treatment.

Persistent fat malabsorption in cystic fibrosis; lessons from patients and mice

Fat malabsorption in pancreatic insufficient cystic fibrosis (CF) patients is classically treated with pancreatic enzyme replacement therapy (PERT). Despite PERT, intestinal fat absorption remains insufficient in most CF patients. Several factors have been suggested to contribute to the persistent fat malabsorption in CF (CFPFM). We reviewed the current insights concerning the proposed causes of CFPFM and the corresponding intervention studies. Most data are obtained from studies in CF patients and CF mice. Based on the reviewed literature, we conclude that alterations in intestinal pH and intestinal mucosal abnormalities are most likely to contribute to CFPFM. The presently available data indicate that acid suppressive drugs and broad spectrum antibiotics could be helpful in individual CF patients for optimizing fat absorption and/or nutritional status.

Determinants of accelerated small intestinal transit in alcohol-related chronic pancreatitis

Patients with chronic pancreatitis may have abnormal gastrointestinal transit, but the factors underlying these abnormalities are poorly understood. Gastrointestinal transit was assessed, in 40 male outpatients with alcohol-related chronic pancreatitis and 18 controls, by scintigraphy after a liquid meal labeled with (99m)technetium-phytate. Blood and urinary glucose, fecal fat excretion, nutritional status, and cardiovascular autonomic function were determined in all patients. The influence of diabetes mellitus, malabsorption, malnutrition, and autonomic neuropathy on abnormal gastrointestinal transit was assessed by univariate analysis and Bayesian multiple regression analysis. Accelerated gastrointestinal transit was found in 11 patients who showed abnormally rapid arrival of the meal marker to the cecum. Univariate and Bayesian analysis showed that diabetes mellitus and autonomic neuropathy had significant influences on rapid transit, which was not associated with either malabsorption or malnutrition. In conclusion, rapid gastrointestinal transit in patients with alcohol-related chronic pancreatitis is related to diabetes mellitus and autonomic neuropathy.

Enteric circular muscle dysfunction in the cystic fibrosis mouse small intestine

BACKGROUND Cystic fibrosis (CF) has multiple effects on the gastrointestinal system, including altered motility. The Cftr knockout mouse model of CF has impaired small intestinal transit but the mechanism is unknown. METHODS Behaviour of circular smooth muscle was studied in an organ bath. Expression levels of prostaglandin (PG) degradative genes were measured by quantitative RT-PCR, and PGE(2) levels were measured by enzyme immunoassay. KEY RESULTS Cystic fibrosis circular muscle activity was erratic and had variable frequency of contractions, as compared to WT. The CF tissue was non-responsive to cholinergic stimulation or direct KCl depolarization. PGE(2) and PGF(2alpha) are significantly elevated in the CF mouse small intestine, and we hypothesized these contribute to impaired smooth muscle activity. After inhibition of PG synthesis, the CF circular muscle exhibited greater cholinergic responsiveness, which was reversed by exogenous PGE(2). PGF(2alpha) enhanced activity of CF tissue only after inhibition of PG synthesis. The enteric microbiota was implicated in PGE(2)-mediated dysmotility because broad spectrum antibiotic treated WT mice, which have slowed transit, exhibit impaired circular muscle activity. This was accompanied by decreased expression of PG degradative genes and increased intestinal PGE(2) levels. Furthermore, administration of oral laxative, which eradicates bacterial overgrowth and improves transit in CF mice, increased expression of PG degradative genes, decreased PGE(2) levels, and improved CF muscle activity. CONCLUSIONS & INFERENCES These results suggest that the enteric microbiota modulates PGE(2) levels in a complex manner, which affects enteric smooth muscle activity and contributes to slower small intestinal transit in CF.

Constipation in pediatric cystic fibrosis patients: an underestimated medical condition

BACKGROUND

The aims of this study were to determine prevalence, risk factors and treatment of constipation in patients with Cystic Fibrosis (CF), as well as the diagnostic value of abdominal radiography.

METHODS

A cohort of 214 pediatric CF patients was investigated. Furthermore, 106 abdominal radiographs of CF patients with or without constipation were independently assessed by three observers on two separate occasions using the Barr and Leech scores.

RESULTS

The prevalence of constipation was 47%. Low total fat absorption and meconium ileus were independent risk factors for constipation in CF, while fiber and fluid intake were not associated. In CF patients the inter and intraobserver variabilities of the Barr and Leech scores were poor to moderate.

CONCLUSION

Constipation is a significant medical issue in CF and was associated with low total fat absorption and a history of meconium ileus. Finally, abdominal radiography seems of little value in the regular follow-up of CF patients.

Gastric acid inhibition for fat malabsorption or gastroesophageal reflux disease in cystic fibrosis: longitudinal effect on bacterial colonization and pulmonary function

OBJECTIVES

To investigate bacterial colonization and pulmonary function longitudinally in patients with cystic fibrosis (CF) receiving drugs for gastric acid (GA) inhibition for fat malabsorption or for gastroesophageal reflux disease (GERD).

STUDY DESIGN

A retrospective cohort study of 218 pediatric patients with CF was performed. Multilevel modeling was used to perform longitudinal analysis of forced expiratory volume in 1 second (FEV(1)), forced vital capacity (FVC), maximum expiratory flow at 50% of FVC (MEF(50)), and maximal mid-expiratory flow between 25% and 75% of FVC (MMEF(25-75)). Cox regression was used to calculate Pseudomonas aeruginosa- and Staphylococcus aureus-free survival.

RESULTS

Patients with CF and GA inhibition had a significantly smaller yearly decline of MEF(50) and MMEF(25-75) compared with control subjects. Other pulmonary function parameters and P aeruginosa or S aureus acquisition or colonization were not different from that of control subjects. GERD was associated with a significantly reduced pulmonary function (FEV(1) and FVC) and an earlier acquisition of P aeruginosa and S aureus.

CONCLUSIONS

GA inhibition did not affect pulmonary function or bacterial acquisition and therefore is not contraindicated in patients with CF. GA inhibition might improve pulmonary function with time, because the decline of MEF(50) and MMEF(25-75) was less pronounced. GERD was associated with a reduced pulmonary function and an earlier acquisition of P aeruginosa and S aureus. Therefore the diagnosis and treatment of GERD should be aggressively pursued in patients with CF.

Application of the glucose hydrogen breath test for the detection of bacterial overgrowth in patients with cystic fibrosis--a reliable method?

Patients with cystic fibrosis (CF) have recently been deemed highly susceptible for bacterial intestinal overgrowth (BIO). We aimed to define the prevalence of BIO in children with CF by applying the H(2)-glucose breath test. Forty children with CF and ten healthy children received 1 g/kg D-glucose orally. Breath samples for H(2) content (ppm) were collected for 3 h. BIO was suspected if the breath hydrogen content increased by more than 20 ppm or if baseline concentrations topped 20 ppm. In 27 of 40 CF children (68%), breath hydrogen content exceeded 20 ppm. Whereas the breath hydrogen exhalation persisted above 20 ppm in almost all these children throughout the sampling period, none of the remaining children increased above this threshold. The high rate of CF children with elevated fasting hydrogen breath concentrations indicates that this phenomenon is less a sign of BIO rather than a consequence of global malabsorption and intestinal dysmotility.

Influence of previously ingested wheat on fasting breath hydrogen in celiac patients

The excretion of hydrogen in breath commonly persists, despite an overnight fast. Although the elevation of hydrogen concentration above the fasting value after the administration of a test sugar is evidence of malabsorption, the level of the fasting value itself in untreated celiac patients is unknown. Therefore, we studied the fasting breath hydrogen (FBH(2)) concentration in 40 healthy controls, 35 subjects with functional bowel disorders, and 30 patients of untreated celiac disease with and without bread or wheat diet one day before the test. The fasting level of hydrogen concentration in untreated celiac patients (28.7 +/- 19.5 ppm) was significantly higher than those in healthy volunteers (9.5 +/- 3.4 ppm) and subjects with functional bowel disorders (10.6 +/- 4.5 ppm). The percentage of patients with elevated H(2) fasting levels in untreated celiac disease (82.5%) was significantly higher than that in healthy controls (10%) and subjects with functional bowel disorders (17.1%). In 30 celiac patients, studied with and without wheat-free diet one day before the test, the fasting hydrogen levels decreased from 28.7 +/- 19.5 ppm to 10.6 +/- 3.5 ppm, and becoming normal in all patients of celiac disease. Our results show that the patients of untreated celiac disease should be instructed not to eat things made up of wheat one day before hydrogen breath testing so that the normal fasting hydrogen concentration can be obtained and false-negative hydrogen breath test results can be avoided.

Mast cells and gastrointestinal dysmotility in the cystic fibrosis mouse

BACKGROUND

Cystic fibrosis (CF) has many effects on the gastrointestinal tract and a common problem in this disease is poor nutrition. In the CF mouse there is an innate immune response with a large influx of mast cells into the muscularis externa of the small intestine and gastrointestinal dysmotility. The aim of this study was to evaluate the potential role of mast cells in gastrointestinal dysmotility using the CF mouse (Cftr(tm1UNC), Cftr knockout).

METHODOLOGY

Wild type (WT) and CF mice were treated for 3 weeks with mast cell stabilizing drugs (ketotifen, cromolyn, doxantrazole) or were treated acutely with a mast cell activator (compound 48/80). Gastrointestinal transit was measured using gavage of a fluorescent tracer.

RESULTS

In CF mice gastric emptying at 20 min post-gavage did not differ from WT, but was significantly less than in WT at 90 min post-gavage. Gastric emptying was significantly increased in WT mice by doxantrazole, but none of the mast cell stabilizers had any significant effect on gastric emptying in CF mice. Mast cell activation significantly enhanced gastric emptying in WT mice but not in CF mice. Small intestinal transit was significantly less in CF mice as compared to WT. Of the mast cell stabilizers, only doxantrazole significantly affected small intestinal transit in WT mice and none had any effect in CF mice. Mast cell activation resulted in a small but significant increase in small intestinal transit in CF mice but not WT mice.

CONCLUSIONS

The results indicate that mast cells are not involved in gastrointestinal dysmotility but their activation can stimulate small intestinal transit in cystic fibrosis.

Long-term effects of lipase inhibition by orlistat on gastric emptying and orocecal transit time of a solid meal

BACKGROUND

We assessed the impact of a prolonged lipase inhibition upon gastric emptying (GE) and orocecal transit time (OCTT) of a 355-kcal low-fat solid meal.

METHODS

In double-blind manner, 40 obese women BMI > 30 kg/m2, randomly allocated into two equal groups, took orally t.i.d. 120 mg orlistat or placebo during 8 weeks of a weight-reducing management. At randomization and after 2 months, GE was measured simultaneously with OCTT by means of a 13C-octanoic acid and a hydrogen breath test, respectively. Lipolytic activity was evaluated with a 13C-mixed triglyceride breath test (13C-MTGBT).

RESULTS

A profound lipase inhibition by orlistat was confirmed by a 79.5% +/- 16.9% reduction of the cumulative 6-h 13C recovery with 13CMTGBT. GE remained unchanged either in the orlistat (T1/2, 188 +/- 35 min start versus 198 +/- 36 min end) or the placebo (T1/2, 191 +/- 35 min start versus 180 +/- 39 min end) group. OCTT increased from 208 +/- 54 min to 271 +/- 64 min (P < 0.01) after orlistat treatment and did not change significantly (216 +/- 76 vs. 234 +/- 72 min) in the placebo group.

CONCLUSIONS

No adverse effect on the GE and a moderate prolongation of the OCTT of a low-fat solid meal is to be expected under a prolonged treatment with orlistat at a typical dosage regimen.

Altered eicosanoid metabolism in the cystic fibrosis mouse small intestine

OBJECTIVES

Imbalances in essential fatty acid levels have been reported in cystic fibrosis (CF), which may relate to elevated proinflammatory eicosanoid generation. The aim of this work was to better define eicosanoid metabolism in the CF intestine.

MATERIALS AND METHODS

We used the small intestine of the cystic fibrosis transmembrane conductance regulator knockout mouse (CF mouse) to measure eicosanoid metabolic gene expression by quantitative reverse transcription polymerase chain reaction and Western blot, and eicosanoid levels by enzyme immunoassay, as compared with wild-type (WT) littermates.

RESULTS

In the CF small intestine, expression of the secretory phospholipase A2 Pla2g5 mRNA was upregulated to 980% of WT levels. The following were downregulated: leukotriene C4 synthase Ltc4s (mRNA 55% of WT); omega-hydroxylase cytochrome P450s Cyp2c40 (mRNA 54% of WT), and Cyp4a10 (mRNA 4% of WT); and the major prostaglandin degradative enzymes prostaglandin dehydrogenase Hpgd (mRNA 27% of WT) and leukotriene B4 12-hydroxydehydrogenase/15-oxo-prostaglandin 13-reductase Ltb4dh (mRNA 64% and protein 30% of WT). The prostaglandins PGE2 and PGF2alpha were increased to 400% to 600% of WT levels in the CF mouse intestine, and the hydroxyeicosatetraenoic acids (HETEs) 12-, 15-, and 20-HETE were decreased to 3% to 20% of WT levels.

CONCLUSIONS

There are changes in eicosanoid metabolic gene expression that are accompanied by significant changes in specific eicosanoid levels. These changes are expected to play important roles in the pathophysiology of CF in the intestine.

Effects of laxative and N-acetylcysteine on mucus accumulation, bacterial load, transit, and inflammation in the cystic fibrosis mouse small intestine

The accumulation of mucus in affected organs is characteristic of cystic fibrosis (CF). The CF mouse small intestine has dramatic mucus accumulation and exhibits slower interdigestive intestinal transit. These factors are proposed to play cooperative roles that foster small intestinal bacterial overgrowth (SIBO) and contribute to the innate immune response of the CF intestine. It was hypothesized that decreasing the mucus accumulation would reduce SIBO and might improve other aspects of the CF intestinal phenotype. To test this, solid chow-fed CF mice were treated with an osmotic laxative to improve gut hydration or liquid-fed mice were treated orally with N-acetylcysteine (NAC) to break mucin disulfide bonds. Treatment with laxative or NAC reduced mucus accumulation by 43% and 50%, respectively, as measured histologically as dilation of the intestinal crypts. Laxative and NAC also reduced bacterial overgrowth in the CF intestine by 92% and 63%, respectively. Treatment with laxative normalized small intestinal transit in CF mice, whereas NAC did not. The expression of innate immune response-related genes was significantly reduced in laxative-treated CF mice, whereas there was no significant effect in NAC-treated CF mice. In summary, laxative and NAC treatments of CF mice reduced mucus accumulation to a similar extent, but laxative was more effective than NAC at reducing bacterial load. Eradication of bacterial overgrowth by laxative treatment was associated with normalized intestinal transit and a reduction in the innate immune response. These results suggest that both mucus accumulation and slowed interdigestive small intestinal transit contribute to SIBO in the CF intestine.

Altered transit and bacterial overgrowth in the cystic fibrosis mouse small intestine

Small intestinal bacterial overgrowth (SIBO) may play an important role in the gastrointestinal complications of cystic fibrosis (CF). This work explored two potential factors in development of SIBO in the CF (cftr(tm1UNC)) mouse: impaired Paneth cell innate defenses and altered gastrointestinal motility. Postnatal differentiation of Paneth cells was followed by Defcr, Lyzs, and Ang4 gene expression, and SIBO was measured by quantitative PCR of the bacterial 16S rRNA gene. Paneth cell gene expression was low in 4-day-old CF and wild-type (WT) mice and increased similarly in both groups of mice between 12 and 16 days. Peak Paneth cell gene expression was reached by 40 days of age and was less for Defcr and Lyzs in CF mice compared with WT, whereas Ang4 levels were greater in CF mice. SIBO occurred by postnatal day 8 in CF mice, which is before Paneth cell development. With the use of gavaged rhodamine-dextran to follow motility, gastric emptying in CF mice was slightly decreased compared with WT, and small intestinal transit was dramatically less. Since antibiotics improve weight gain in CF mice, their effects on gastric emptying and small intestinal transit were determined. Antibiotics did not affect gastric emptying or transit in CF mice but did significantly slow intestinal transit in WT mice, suggesting a potential role of normal microflora in regulating transit. In conclusion, small intestinal transit was significantly slower in CF mice, and this is likely a major factor in SIBO in CF.

Risk factors for small bowel bacterial overgrowth in cystic fibrosis

OBJECTIVES

The purpose of this study was to determine the prevalence of small bowel bacterial overgrowth in patients with pancreatic-insufficient cystic fibrosis (CF) compared with age-matched controls and to identify potential risk factors for small bowel bacterial overgrowth.

PATIENTS AND METHODS

Fifty patients, 25 pancreatic-insufficient CF study patients (mean age, 17 y) and 25 gastrointestinal clinic control patients (mean age, 15 y), completed a glucose-hydrogen breath test after an overnight fast. Study patients completed a quality-of-life questionnaire modified from the Cystic Fibrosis Questionnaire. The medical history of each patient was compared with breath test results. A positive breath test was defined as a fasting hydrogen > or =15 ppm or a rise of > or =10 ppm hydrogen over baseline during the test.

RESULTS

The prevalence of positive breath tests was higher in the CF study group (56%) than in the control group (20%) (P = 0.02). The mean fasting hydrogen levels of patients in the study and control groups were 22 and 5 ppm (P = 0.0001). The mean questionnaire scores were not significantly different between breath test-positive and -negative study patients. The use of azithromycin was associated with an increased risk of a positive breath test. Use of laxatives and inhaled ipratropium was associated with a decreased risk of a positive breath test.

CONCLUSIONS

Patients with CF were more likely to have elevated fasting hydrogen levels compared with controls. This suggests a high prevalence of small bowel bacterial overgrowth in CF patients. Medications commonly used by CF patients may influence intestinal health.

Mechanisms of lipid malabsorption in Cystic Fibrosis: the impact of essential fatty acids deficiency

Transport mechanisms, whereby alimentary lipids are digested and packaged into small emulsion particles that enter intestinal cells to be translocated to the plasma in the form of chylomicrons, are impaired in cystic fibrosis. The purpose of this paper is to focus on defects that are related to intraluminal and intracellular events in this life-limiting genetic disorder. Specific evidence is presented to highlight the relationship between fat malabsorption and essential fatty acid deficiency commonly found in patients with cystic fibrosis that are often related to the genotype. Given the interdependency of pulmonary disease, pancreatic insufficiency and nutritional status, greater attention should be paid to the optimal correction of fat malabsorption and essential fatty acid deficiency in order to improve the quality of life and extend the life span of patients with cystic fibrosis.

Electrogastrography in children with cystic fibrosis

Patients with cystic fibrosis often develop upper gastrointestinal symptoms, which may be due to abnormal gastric motor function. The aim of the study is to determine the characteristics of gastric electrical activity in patients with cystic fibrosis and to compare electrogastrography patterns in symptomatic and asymptomatic patients. Electrogastrography was recorded in 14 symptomatic and 8 asymptomatic children with CF. Both 30-min baseline and 30-min postprandial recordings was obtained. Dominant frequency cycles per minute, rhythm index, and power in decibels were obtained for the fasting and postprandial periods. The percentage of normal gastric waves was not affected by the meal and was significantly low in symptomatic and asymptomatic cystic fibrosis patients. Tachygastria was the most frequent dysrhythmia in both groups. Decreased postprandial power was seen in three symptomatic patients and one patient had no change. The percentage of normal gastric slow waves was low in symptomatic and asymptomatic cystic fibrosis patients. Tachygastria was the most frequent dysrhythmia. Decreased postprandial power was seen only in symptomatic patients.

Gastric emptying and intestinal transit of pancreatic enzyme supplements in cystic fibrosis

OBJECTIVE

To investigate gastric emptying and intestinal transit of pelleted pancreatin in relation to food boluses.

METHODS

Dual isotope scintigraphy combined with breath hydrogen sampling was used to track the concurrent gastric emptying and intestinal transit of 111indium labelled microspheres and a 99mtechnetium labelled tin colloid test meal. Twelve pancreatic insufficient cystic fibrosis patients aged 5 to 38 years performed the study.

RESULTS

50% gastric emptying times showed patient to patient variation. The mean discrepancy in 50% gastric emptying times between the two labels was > 67 minutes. Mean small bowel transit time for the food bolus was prolonged at 3.6 minutes. A significant correlation was seen between weight standard deviation score and 50% emptying time for pancreatin (r = +0.73).

CONCLUSION

Gastric mixing of food and pancreatin may be limited by rapid emptying of microspheres. Patients with high dosage requirements could benefit from changing the pattern of their pancreatin supplementation.

Gastric emptying time is faster in cystic fibrosis

BACKGROUND

The high energy requirements in cystic fibrosis (CF) increase the likelihood of malnutrition. Delayed mouth-to-cecum transit times have been reported and raise the possibility that abnormalities of gastric function in CF contribute to reduced food intake. The aims of this project were to document solid-phase gastric emptying times in young people with CF and age- and sex-matched healthy controls, and to investigate whether delayed gastric emptying contributes to suboptimal energy intakes.

METHODS

Nineteen subjects with CF, mean age 12.6 years (11 girls and 8 boys), and 17 control subjects, mean age 12.8 years (9 girls and 8 boys), were studied. Energy intake was assessed by means of a 4-day weighed food record. Fecal fat excretion was determined from a 3-day stool collection. Gastric emptying was assessed with a standard test meal of pancakes labeled with 99mTc-macroalbumin aggregates. The half emptying time of solids from the stomach was recorded.

RESULTS

The mean solid-phase gastric emptying time was significantly faster in the CF subjects compared with normal, healthy, age- and sex-matched control subjects (53 min vs. 72.2 min, p < 0.05). Energy intakes, measured as the percentage of the recommended energy intake for age and sex, were greater in the CF subjects than in the control subjects (115% vs. 89%, p < 0.01), whereas the mean % FFE for the CF subjects was 9.9%. CF subjects with longer gastric emptying times also had lower relative energy intakes (r = -0.50, p < 0.05).

CONCLUSION

Gastric emptying time in healthy subjects with CF is rapid. Faster solid-phase gastric emptying times may be secondary to high-fat, high-energy intakes and may represent a survival advantage.

Plasma concentrations of cholecystokinin and neurotensin in patients with cystic fibrosis

BACKGROUND

Regulation of pancreatic exocrine secretion is controlled by vagovagal reflexes and hormones. A negative feedback control mechanism exists between the intraduodenal protease concentration and pancreatic enzyme secretion. In man cholecystokinin (CCK) is the major regulator of postprandial pancreatic enzyme secretion. There is a 50% reduction of meal-stimulated secretion by the specific CCK receptor antagonist loxiglumide, whereas atropine completely blocks postprandial secretion. Neurotensin is released postprandially by nerval reflexes and fat. It has been claimed that both hormones are increased in patients with pancreatic insufficiency.

METHODS

We investigated CCK and neurotensin levels in patients with cystic fibrosis and pancreatic insufficiency. In 35 patients (2-24 years old) with cystic fibrosis with steatorrhea and in 15 patients (1.5-24 years old) with cystic fibrosis without pancreatic insufficiency pre- and post-prandial CCK and neurotensin plasma levels were measured 3 days after pancreatic enzyme therapy had been withdrawn. Nine patients (3-14 years old) who had no complaint of abdominal disease served as controls.

RESULTS

Basal and postprandial CCK plasma levels did not differ statistically in the three groups, whereas basal and postprandial neurotensin levels were significantly increased in the cystic fibrosis groups. The severity of the disease had no effect on the neurotensin levels.

CONCLUSIONS

Cystic fibrosis patients with severe pancreatic insufficiency did not have increased CCK plasma levels, suggesting that a CCK-mediated feedback mechanism of pancreatic enzyme secretion does not operate in our patients. In contrast, basal and postprandial neurotensin plasma levels were significantly increased in patients with cystic fibrosis but were independent of the severity of the pancreatic insufficiency.

Gastrointestinal pH, motility/transit and permeability in cystic fibrosis

I reviewed the literature (1966-1994) concerning gastrointestinal (GI) pH, motility/transit, and permeability in cystic fibrosis (CF). Most studies reported were performed with very small numbers of patients, but even when considered together the published data do not confirm some generally expressed views on these topics. The only clear findings were a high incidence of gastroesophageal reflux in CF; pre- and postprandial duodenal pH is 1-2 U lower in patients with CF than in healthy controls; and small intestinal paracellular permeability is 4-10 times greater than normal in CF. Some patients showed abnormalities of lower esophageal sphincter pressure and of esophageal motility, but apart from one case study other disturbances of GI motility have not been reported. The results of hydrogen breath tests strongly suggest that oro-cecal transit is slowed in CF, but these results must be confirmed by an alternative test. Measurements of colonic transit and colonic permeability have not been reported. The few studies of gastric emptying reported are controversial. Whether GI pH, apart from duodenal pH, is normal in CF or whether a subset of patients has exceptionally acid intestinal contents requiring specialized pancreatic enzyme supplementation to normalize digestion is not clear. Finally, I briefly discuss the findings in relation to their possible impact on the pathogenesis of fibrosing colonopathy.

In vivo measurement of chloride and water secretion in the jejunum of cystic fibrosis patients

In the present study, we have investigated the possible consequences of the chloride channel defect in the intestine of cystic fibrosis (CF) patients for electrolyte and water transport in the jejunum in vivo, using a multilumen, double occluding balloon catheter, and an Ag/AgCl intraluminal electrode. During a chloride-free perfusion, to optimize the sensitivity of our measurements, the transmural potential difference (PD) (lumen with reference to serosal side) was found to be significantly higher in the jejunum of CF patients (+8.0 +/- 2.1 mV; n = 5) than in healthy control subjects (-2.2 +/- 2.0 mV; n = 9). The chloride concentration measured in chloride-free jejunal perfusates of CF patients was significantly lower than in controls (10.9 +/- 2.3 and 41.4 +/- 8.2 mM, respectively). Possible differences in net chloride and water secretion did not reach statistical significance (chloride secretion controls: -2.1 +/- 0.9 mmol/10 cm/h; CF: -0.8 +/- 0.2 mmol/10 cm/h; water secretion controls: -0.8 +/- 2.5 mL/10 cm/h; CF: -11.7 +/- 8.9 mL/10 cm/h). In control subjects, intraluminally applied theophylline stimulated the secretion of water (delta 23.4 +/- 4.6 mL/10 cm/h) and chloride (delta 4.1 +/- 1.1 mmol/10 cm/h), but not in CF patients (respectively delta 3.6 +/- 3.3 mL/10 cm/h and delta 1.1 +/- 1.1 mmol/10 cm/h). In controls, theophylline caused a significant increase in lumen negativity (PD -10.2 +/- 2.6 mV), but no change could be seen in CF patient transmural PD. These observations provide in vivo evidence for a decreased chloride permeability in the jejunum in CF, resulting in a significant reduction in net electrolyte and water secretion in the presence, but not in the absence, of an intestinal secretagogue.

Functional iron deficiency in adults with cystic fibrosis

Functional iron deficiency (transferrin saturation < 16%) was found in 44 (62%) of 71 adult cystic fibrosis (CF) patients. Haemoglobin concentration and mean cell volume were lower in iron-deficient patients, in whom there was a non-significant trend for lower serum ferritin. Ten iron-deficient patients and two patients with transferrin saturation > = 16% (normal iron) were anaemic. There were no significant differences between iron-deficient and normal-iron patients in intake of calories, protein, iron and vitamin C as determined by 4-day records of dietary intake. Dietary iron deficiency is not an important factor in functional iron deficiency in adult CF patients. Impairment of absorption by exogenous pancreatic enzyme supplements is unlikely to be significant as enzyme intake was the same in the two groups. Iron-deficient patients had lower Shwachman-Kulczycki scores and lower percent predicted forced expiratory volume in 1 s (FEV1% predicted) and forced vital capacity (FVC% predicted). There was a non-significant trend for higher values of white cell count and plasma viscosity in the iron-deficient group. Chronic inflammation is likely to be the primary cause of functional iron deficiency in adult CF patients. Fifteen patients completed 3-month courses of oral iron replacement with no deterioration in pulmonary function, but with no effect on haemoglobin concentration.

Intestinal permeability in exocrine pancreatic insufficiency due to cystic fibrosis or chronic pancreatitis

Disturbances of the intestinal integrity, reflected by an increased intestinal permeability, are reported in cystic fibrosis (CF). Controversy exists whether the increased intestinal permeability is due to CF itself or a consequence of the concomitant exocrine pancreatic insufficiency (PI). We measured intestinal permeability by the sugar absorption test in 32 PI patients: 20 CF-PI, 12 nonCF-PI with chronic pancreatitis, and 50 controls. In the sugar absorption test, the lactulose/mannitol ratio is measured in 5-h urine samples after oral ingestion of a solution of lactulose and mannitol, hyperosmolar by the addition of sucrose. The lactulose/mannitol ratio was increased in both CF-PI and nonCF-PI versus controls (p < 0.0001). In CF, the L/M ratio and permeability for lactulose and mannitol did not change by increasing pancreatic enzyme supplementation by 30-50% for 2 wk (p = 0.74, p = 0.97, p = 0.74, respectively) nor by decreasing the osmolarity of the test solution by 75% (p = 0.24, p = 0.10, p = 0.39, respectively). We conclude that an increased intestinal permeability in CF is probably a consequence of PI and is not related to the dose of pancreatic enzyme supplementation nor the osmolarity of the test solution. The increase is due to an increased permeability for lactulose which might point toward a defect in the tight junctions of the villi and/or crypts. The cause of the increased intestinal permeability in the presence of PI is still unclear. An increased intestinal permeability points toward an impaired functional integrity of the small bowel, which may contribute to gastrointestinal dysfunction in CF.

Ultrasound measurement of gastric emptying time in patients with cystic fibrosis and effect of ranitidine on delayed gastric emptying

Intestinal dysmotility is commonly reported in patients with cystic fibrosis (CF); however, gastric motor activity has rarely been investigated. We measured with real-time ultrasonography the antral distention and gastric emptying time of a solid-liquid meal in 29 patients with CF (age range, 5 to 17 years). A significantly prolonged gastric emptying time was present in 26 patients compared with 13 healthy control subjects (age range, 5 to 16 years); an exaggerated antral distention in the fed period was also detected. The patients with CF and delayed gastric emptying were randomly allocated to receive cisapride or ranitidine for 4 weeks. Twelve patients treated with ranitidine and 11 with cisapride completed the trial. There was a marked decrease in gastric emptying time, antral distention, and dyspeptic symptomatic score in patients receiving ranitidine but not in patients treated with cisapride. We conclude that gastric dysmotility is commonly detected in patients with CF and that H2 receptor blockers are more effective than prokinetics in improving dyspeptic symptoms and gastric emptying and distention.

Plasma concentrations and effects of salbutamol administered orally to patients with cystic fibrosis

1. To test whether cystic fibrosis (CF) altered the kinetics and dynamics of oral salbutamol, 11 patients with CF (19-33 years old; five females; FEV1: 37 +/- 12% of predicted value) and 10 healthy volunteers (20-41 years old; five females; FEV1: 99 +/- 14% of predicted value) received orally 4 mg salbutamol. 2. The estimated pharmacokinetic parameters of salbutamol in patients with CF were identical to those in healthy subjects. For instance, peak plasma concentrations of salbutamol were 10.5 +/- 2.6 (mean +/- s.d.) and 10.2 +/- 2.9 ng ml-1 (NS), and the area under salbutamol plasma concentrations as a function of time (AUC (0, 7 h)) was 43.0 +/- 9.3 ng ml-1 h and 43.3 +/- 12.7 ng ml-1 h (NS) in CF patients and in healthy subjects, respectively. Since on a mg kg-1 dose basis, CF patients received a dose 28% greater than healthy subjects, this lack of differences implies a decrease in the amount of salbutamol absorbed, or alternatively, an increase in both clearance and volume of distribution of salbutamol. 3. Salbutamol did not elicit bronchodilation in CF patients, but increased heart rate from 77 +/- 2 to 103 +/- 3 beats min-1 (P < 0.05). 4. Salbutamol decreased plasma potassium concentrations from 4.5 +/- 0.1 to 3.8 +/- 0.1 mmol l-1 in the CF group (P < 0.05) and from 4.1 +/- 0.2 to 3.4 +/- 0.1 mmol l-1 in the controls (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cystic fibrosis, pancreatic sufficiency and distal intestinal obstruction syndrome: a report of four cases

Distal intestinal obstruction syndrome (DIOS), formerly termed meconium ileus equivalent, is usually considered to be unique to cystic fibrosis (CF) patients who have steatorrhoea. We report four CF patients without steatorrhoea ("pancreatic sufficient") who have had repeated episodes of faecal loading indistinguishable from DIOS.

Relation of thickening of colon wall to pancreatic-enzyme treatment in cystic fibrosis

Fibrotic strictures of the colon in association with colon-wall thickening on abdominal ultrasound have been described in children with cystic fibrosis. We determined the prevalence of colon-wall thickening in 99 children with cystic fibrosis (aged 6 months to 17 years, 45 male) and 38 healthy controls (aged 1 month to 39 years, 21 male). In controls, peristalsis was uniformly rapid and maximum wall thickness of the fully relaxed colon was 0.8 mm (median 0.6 mm). 24% of the patients had a colon-wall thickness of 1.5 mm or more (maximum 3.4 mm); 48% of children on high-strength pancreatin receiving more than 265 units/kg per day of protease had thickening of more than 1.5 mm compared with less than 12% of children on any other dose. Children on high-strength pancreatin were 5.2 (95% CI 1.2-21) times more likely to have colon-wall thickness of 1.5 mm or more than children taking less than 265 units/kg per day of protease in a standard-strength preparation. This risk rose to 10 (2.5-39) times more likely if laxatives were taken with a high-strength preparation. Lipase or amylase intake, age, sex, genotype, and other medical or drug history were not significantly associated with colon-wall thickening. 1 child required a hemicolectomy for bowel obstruction and another developed haemorrhagic colitis. In 17 children, 2 months after stopping high-strength, high protease, preparations and efforts to reduce enzyme intake, colon-wall thickness had regressed from a median 2.0 mm (range 1.0-3.4) to 1.8 mm (0.9-2.7) (p = 0.005). The use of high-strength pancreatin preparations in conjunction with a high protease intake probably causes thickening of the wall of the colon.

Comparison of a high lipase pancreatic enzyme extract with a regular pancreatin preparation in adult cystic fibrosis patients

BACKGROUND

Malabsorption due to exocrine pancreatic insufficiency is the main gastrointestinal problem in cystic fibrosis. Despite high doses of pancreatic enzyme supplements it is often not possible to normalize fat absorption. We compared a new high lipase pancreatic enzyme preparation (Pancrease-HL; Cilag, Brussels, Belgium), containing enteric coated microspheres with 25,000 U of lipase, 22,500 U of amylase and 1250 U of protease per capsule, with regular Pancrease capsules, containing 5000 U of lipase, 2900 U of amylase and 330 U of protease per capsule.

METHODS

In a randomized double-blind crossover study, 13 cystic-fibrosis patients (6 male, 7 female, mean age 27.7 years) received either four capsules of Pancrease t.d.s. or one capsule of Pancrease-HL t.d.s. Patients took 20 mg omeprazole daily to raise intra-duodenal pH and thus optimize release of enzymes from the enteric coated microspheres.

RESULTS

With four capsules of Pancrease t.d.s., mean fat excretion was 15.4% and mean nitrogen excretion was 19.9% vs. 15.5% fat and 19.9% nitrogen excretion with one capsule Pancrease-HL t.d.s. Fat and protein energy loss (as a percentage of total daily intake) was 18.3% with Pancrease and 18.2% with Pancrease-HL. The differences were not statistically significant. Pancrease-HL was well tolerated, with no difference in abdominal pain or general well-being scores. The number and average weight of stools passed remained the same.

CONCLUSIONS

One capsule of Pancrease-HL appears to be equivalent to four capsules of regular Pancrease. Treatment with less capsules per day with the same efficacy may facilitate patient compliance.

Chronic intestinal pseudo-obstruction with meconium ileus at onset

Cystic fibrosis is most often the underlying cause of meconium ileus. We describe the diagnosis and treatment of a patient with chronic intestinal pseudo-obstruction, and not with cystic fibrosis, whose initial manifestation was meconium ileus.

Detection of malabsorption of low doses of carbohydrate: accuracy of various breath H2 criteria

BACKGROUND

Although the accuracy of breath H2 testing to detect malabsorption of small (< 50 g) doses of carbohydrate has never been evaluated, studies suggest that its accuracy is limited by a high prevalence of "H2 nonproducers." The aim of this study was to determine the accuracy of H2 breath testing in the detection of malabsorption of 10 g of carbohydrate.

METHODS

In 55 healthy subjects, we determined the ability of breath H2 measurements to distinguish between the ingestion of 10 g of a nonabsorbable carbohydrate (lactulose) and two control meals, a nonabsorbable electrolyte solution or glucose (10 g).

RESULTS

The conventional criterion of a 20 ppm increase in breath H2 had 100% specificity but failed to identify lactulose malabsorption in 47% and 24% of subjects at 4 and 8 hours of testing. In contrast, a breath H2 of > 6 ppm at 5 or 6 hours had near perfect specificity and sensitivity. A sum of breath H2 at 5, 6, and 7 hours of > 15 ppm yielded perfect separation between lactulose and control solutions.

CONCLUSIONS

True "H2 nonproducers" are extremely rare. Using appropriate criteria, breath H2 testing provides a very accurate means of identifying malabsorption of low doses of carbohydrate.

Intestinal bile acid malabsorption in cystic fibrosis

This study aimed at examining the mechanisms participating in excessive faecal bile acid loss in cystic fibrosis. The study was designed to define the relation between faecal fat and faecal bile acid loss in patients with and without cystic fibrosis related liver disease; to assess terminal ileal bile acid absorption by a seven day whole body retention of selenium labelled homotaurocholic acid (SeHCAT); and to determine if small intestinal bacterial overgrowth contributes to faecal bile acid loss. The study population comprised 40 patients (27 men; median age 18 years) with cystic fibrosis (n = 8) and without (n = 32) liver disease and eight control subjects. Faecal bile acid excretion was significantly higher in cystic fibrosis patients without liver disease compared with control subjects (mean (SEM) 21.5 (2.4) and 7.3 (1.2) micromoles/kg/24 hours respectively; p < 0.01) and patients with liver disease (7.9 (1.3) micromoles/kg/24 hours; p < 0.01). No correlation was found between faecal fat (g fat/24 hours) and faecal bile acid (micromoles 24 hours) excretion. Eight (33%) of cystic fibrosis patients had seven day SeHCAT retention < 10% (normal retention > 20%). SeHCAT retention in cystic fibrosis patients with liver disease was comparable with control subjects (30.0 (SEM) 8.3% v 36.8 (5.9)%; p = NS) while SeHCAT retention in cystic fibrosis patients who did not have liver disease was significantly reduced (19.9 (3.8); p < 0.05). Although evidence of small bowel bacterial overgrowth was present in 40% of patients no relation was found between breath hydrogen excretion, faecal fat, and faecal bile acid loss. The results are consistent with the presence of an abnormality in terminal ideal function in patients with cystic fibrosis who do not have liver disease and that a defect in the ileal absorption of bile acids may be a contributory factor to excessive faecal bile acid loss. Faecal bile acid loss in cystic fibrosis is unrelated to the presence of intraluminal fat or intestinal bacterial overgrowth.

Orocaecal transit time in patients with Crohn disease

Orocaecal transit time (OCTT) using the lactulose hydrogen breath test was investigated in 16 patients (age 10-19.4 years) with active Crohn disease (CD). Disease activity was assessed by the paediatric CD activity index (PCDAI). OCTT was prolonged in all patients (mean 149.9 min, SD 32.7) relative to healthy age-matched controls (mean 56.9 min, SD 11.1). PCDAI was increased (median 48.8, range 32.5), indicating moderate to severe disease in all patients. A close correlation between OCTT and PCDAI (Spearman r = 0.90) was observed. Following nutritional therapy with a semi-elemental diet over a period of 6 weeks OCTT and PCDAI declined, OCTT becoming normal in 4 and PCDAI in 4/12 patients respectively. OCTT provides a sensitive, non-invasive method for the assessment and followup investigations in patients with CD.