Cholesterol esterase activities in commercial pancreatic enzyme preparations and implications for use in pancreatic insufficient cystic fibrosis.

BACKGROUND: Although clinical symptoms in pancreatic insufficiency are often dramatically improved by pancreatic preparations, these often fail to normalize biochemical indicators of malabsorption. It seemed relevant, therefore, to investigate the amounts of cholesterol esterase in these preparations and, using in-vitro methods, some of the activities of this enzyme. The enzyme is just as physiologically important as lipase in accomplishing lipid digestion and absorption. METHODS: Cholesterol esterase was assayed in commercial pancreatic extract preparations, lyophilized pig pancreas and human duodenal fluid. The in-vitro activities of the enzyme were also investigated on single and mixed dietary substrates. RESULTS: Other than Creon, the commercial preparations showed negligible cholesterol esterase activities, whereas considerable activities were found in pancreatic tissue and duodenal fluids. In-vitro, pig cholesterol esterase was confirmed to be dependent on 3-hydroxy bile salt concentration for hydrolysis and synthesis and that the rate for hydrolysis greatly exceeds that of synthesis in normal concentrations of bile salts. However, with mixed lipid substrates, no bile salt concentration was found at which hydrolysis or synthesis predominates. CONCLUSIONS: When pancreatic or hepato-biliary function is compromised, optimum lipid hydrolysis may not be achieved in therapeutic use, and the pig enzyme may perform differently to the human enzyme. In-vivo trials may reveal whether augmentation of the commercial products with this enzyme would be worthwhile.

Evaluation of fecal pancreatic elastase-1 as a measure of pancreatic exocrine function in children with cystic fibrosis.

Pancreatic elastase-1 (EL-1) is a specific human protease synthesised by the acinar cells. It is stable, unaffected by exogenous pancreatic enzyme treatment, and correlates well with stimulated pancreatic function tests. We report our experience of EL-1 measurements in 142 patients from a large cystic fibrosis (CF) clinic. The median patient age was 7.7 years (range, 0.1-20.8 years), 93 were homozygous and 38 heterozygous for DeltaF508, and 11 had other or unidentified mutations. There were 85 non-CF control subjects. Seven were pancreatic sufficient (PS). The median (quartile 1-quartile 3) fecal EL-1 of the 135 pancreatic insufficient (PI) patients was 10 microg/g stool (2.5-33); of the 7 PS patients, 698 microg/g stool (400.5-824.5), and of the non-CF controls, 615 microg/g stool (420-773). Using the Mann-Whitney U test, there was a statistically significant difference for fecal EL-1 activity between the PS and PI patients (P = 0.0001) and the PI and control group (P < 0.0001), but not between the control and PS groups (P = 0.63). Median (quartile 1-quartile 3) fecal EL-1 in the pancreatic insufficient DeltaF508 homozygotes was 10 microg/g stool (2-33), and in the heterozygotes 12 microg/g stool (4-39) (not significant, P = 0.62). We now use fecal EL-1 as evidence of PI in screened CF infants (reliable over the age of 2 weeks); in older CF patients at diagnosis; for confirming the need for pancreatic enzymes in patients referred to the clinic already taking enzymes; for annual monitoring of PS patients to detect the onset of PI; and as supporting evidence when excluding the diagnosis of CF in patients attending the pediatric gastroenterology clinic. The low values in the first 2 weeks in some normal and premature infants, and the persisting normal values in PS infants, make the fecal EL-1 test unsuitable for neonatal CF screening.

Faecal bile acid and dietary residue excretion in cystic fibrosis: age group variations.

BACKGROUND: Earlier studies report the excessive faecal excretions of bile acids and dietary residues in cystic fibrosis (CF). However, few of these investigated large groups of patients using modern pancreatin preparations and little data exists reporting carbohydrate excretion. We therefore aimed to characterise the general levels of malabsorption within age groups of 132 patients attending a regional CF centre. METHODS: The faecal excretions of bile acids, fat, nitrogen and carbohydrate were measured. Most of these patients were treated with either (Creon) (n = 58) or Pancrease (n = 51) and prophylactic antibiotics. The patients were grouped in age ranges 0.5 to 5 years, 6 to 10 years, 11 to 15 years and >16 years. Carbohydrate excretion was determined in the 11 to 15 year group. RESULTS: Increased excretions with increment in age group were found which, for bile acids, was twice that of age matched controls. Modest relationships were found between the overall excretion of bile acids and fat, and between the excretion of bile acids and nitrogen. Primary bile acids were a feature of cystic fibrosis stools but the patterns of individual bile acid excretion revealed a trend towards a normal bile acid types with increment in age group. Faecal carbohydrate was significantly increased to levels which may significantly alter large bowel microflora. CONCLUSIONS: The data adds to the evidence that maldigestion initiates bile acid sequestration and consequently, the predominance of primary bile acids.

Pancreatin preparations used in the treatment of cystic fibrosis--lipase content and in vitro release.

BACKGROUND: Pancreatic extracts are essential in the treatment of the majority of cystic fibrosis patients. The clinical response to different preparations is often unpredictable and at present there is no sure method of determining the best preparation for a particular patient. METHODS: Creon, Nutrizym GR, Pancrease and the high-lipase versions, Creon 25,000, Nutrizym 22 and Pancrease HL, were investigated for lipase content and resistance to simulated gastric conditions. The rates of lipase release in response to pH change, bile salts and duodenal solids were investigated. The stability of lipase and its binding to duodenal solids were also investigated. RESULTS: Declared values for lipase content were exceeded in all preparations. All preparations were acid resistant. The release of lipase in response to pH change showed notable differences in release rates. After 20 min at pH 5.5, Creon released three times the amount of lipase compared with Pancrease, the other preparations coming within the range. Above pH 5.75, the release rates were comparable amongst the preparations. Bile salts influenced release variably whilst release in a solid-rich duodenal fluid was much slower than in buffers. The released lipase was susceptible to proteolysis and pH-dependent binding to duodenal solids; these effects may compromise lipolysis. CONCLUSIONS: These results show some factors contributing to variable clinical responses to pancreatic supplements. Improvements may result if a patient is assessed on different preparations.

Decidual histamine release and amplification of prostaglandin F2 alpha production by histamine in interleukin-1 beta-primed decidual cells: potential interactive role for inflammatory mediators in uterine function at term.

Inflammatory cytokines such as interleukin-1 (IL-1) have been implicated as paracrine mediators of decidual prostaglandin (PG) production during preterm labor. The aim of the present in vitro study was to investigate a similar potential role for the inflammatory autacoid histamine. Histamine action on human primary decidual cell cultures was monitored by measuring both PGF2 alpha production and PG precursor release. Histamine release from decidual cell suspensions was measured in response to a variety of putative mast cell secretagogues. Histamine stimulated a dose-dependent increase in PGF2 alpha production and [14C]arachidonate release from prelabeled decidual cells, with ED50 values around 1 and 2 mumol/L, respectively. Pretreatment of cells with IL-1 beta enhanced maximal PGF2 alpha production in response to histamine by approximately 4-fold. Mepyramine, an H1 receptor antagonist, completely blocked this PGF2 alpha response. The mean histamine content of unpurified decidual cells was approximately 81 pmol/10(6) cells. Upon challenge with antihuman immunoglobulin E, these cells exhibited a dose-dependent release of histamine. Basal release from decidual cell suspensions and release in response to antiimmunoglobulin E (1:400) or A23187 (1 mumol/L) were 7.6 +/- 2.7%, 25.5 +/- 0.9%, and 63.5 +/- 5.6% of the total histamine content, respectively. No significant changes in histamine secretion were seen in response to compound 48/80, substance-P, phorbol ester, or bacterial endotoxin. These in vitro findings support a potential role for histamine as a local regulator of phospholipase-A2 and PGF2 alpha production in human term decidua. The interaction of this autacoid with other inflammatory mediators, such as IL-1, could play a role in the control of PG production during preterm labor.

A double blind lipase for lipase comparison of a high lipase and standard pancreatic enzyme preparation in cystic fibrosis.

A standard acid resistant microsphere pancreatic enzyme preparation was compared with identical capsules half filled with mini-tablets of a new high lipase preparation in a randomised double blind crossover study in children with cystic fibrosis. Each patient received his/her usual number of capsules and the same dose of lipase during each period of the study. Eighteen patients completed the study. There were fewer gastrointestinal symptoms when pancreatic enzyme was supplied as the high lipase preparation. There was also a significant improvement in fat absorption (17%, 95% confidence interval (CI) 6 to 27), reduction in faecal fat output (15.8 g/day, 95% CI 6.4 to 22.5), and faecal energy loss (789 kJ/day, 95% CI 211 to 1384). It is concluded that half filled capsules of the new high lipase preparation are more effective than the standard preparation and it is likely that filled capsules would allow patients to use fewer than half the number of pancreatic enzyme capsules.

Clinical monitoring of steatorrhoea in cystic fibrosis.

In 100 patients with cystic fibrosis the severity of steatorrhoea was assessed by three separate methods. Using chemical faecal fat assay as the gold standard, two other rapid and inexpensive methods were compared with it. The steatocrit method proved unreliable in our hands and gave little indication of the presence or severity of steatorrhoea. The more simple microscopy method was highly sensitive (97%) and only three of 80 patients with steatorrhoea were missed. All patients with severe steatorrhoea (greater than 60 mmol fat/day) were clearly demonstrated. The method is applicable to spot faecal samples and can readily be carried out on an outpatient basis. In centres where faecal fat assays are not available, the simple and cheap microscopic examination will give some indication of the response to enzyme treatment and may also help to identify non-compliant individuals.

Preparation and characterization of a [14C]cellulose suitable for human metabolic studies.

In six normal subjects administered 5 microCi of an oral dose of a commercially available 14C-labelled cellulose, significant amounts of 14CO2 were detected in expired air within 30 min, suggesting that other 14C-labelled non-cellulosic material was present. Chemical and microscopical examination confirmed that starch was the principal contaminant. The commercial preparation was purified using amyloglucosidase (EC 3.2.1.3) digestion following gelatinization of the starch by autoclaving. Subsequent administration of the purified cellulose to a further six normal subjects decreased the expired air 14CO2 during the subsequent 10 h from 13.0 (SD 4.0) to 4.1 (SD 1.9)%. Administration of the purified product to a further group of four normal subjects, before and after a regimen of increased dietary fibre, showed a cumulative increase in expired 14CO2 over 24 h from 7.9 (SD 1.1) to 12.1 (SD 2.6)% on fibre. In six ileostomy subjects the cumulative excretion of 14CO2 was greatly decreased compared with normal controls (3.0 (SD 1.14) and 10.5 (SD 3.9)% respectively). In constipated subjects expired 14CO2 continued beyond 48 h, in contrast to normal subjects where expired 14CO2 at this time was negligible.

Markers for faecal fat estimation in monitoring steatorrhoea in cystic fibrosis.

Polyethylene glycol (PEG) 4000 is one of numerous substances used as non-absorbable markers to correct for variable faecal output when assessing daily faecal losses of nutrients. The introduction of enteric coated micro-encapsulated pancreatic enzyme (EMPE) preparations has greatly improved the control of fat malabsorption in cystic fibrosis and chronic pancreatitis patients. Unfortunately, these enzyme preparations contain significant quantities of PEG 4000 or polyvinyl pyrrolidine (PVP) as components of the enteric coating and thus PEG 4000 cannot be used either as a faecal marker, or in intubation studies, if these enzyme preparations are being used.

In vivo and in vitro studies of microsphere pancreatic supplements.

Over the past 5 years, the Leeds Regional Cystic Fibrosis (CF) Unit has provided comprehensive annual assessments of CF patients that include dietary assessments and fat absorption studies. Enteric-coated microsphere pancreatic enzyme preparations (microsphere preparations) were compared to conventional enzymes as therapeutic agents for these patients. Presently in the U.K., two microsphere preparations are licensed for use and a further two products are likely to receive licenses in the near future. The success of these preparations is dependent on the ability of the microsphere coating to resist dissolution until the pH exceeds approximately 5.5 and thus prevent inactivation of lipase in the acid environment of the stomach. A study comparing Pancrex V Forte, a conventional enzyme preparation, to three microsphere preparations, Pancrease, Creon, and pancreatin Merck, confirmed the superiority of Pancrease and Creon over Pancrex V Forte and pancreatin Merck with regard to control of symptoms, and nitrogen and fat absorption. Because of differences in the physical characteristics of various microsphere preparations, the dissolution rates of Pancrease, Creon, and pancreatin Merck were compared in vitro. In aqueous buffers, striking differences among the preparations were seen at pH 5.5; whereas only 25% of available lipase was released from Creon, both Pancrease and pancreatin Merck show almost complete dissolution at this pH. Only at pH 6.5 and above do all three preparations show complete dissolution. In duodenal juice, as in aqueous buffers, lipase release from Creon takes place at a lower rate than with the other two preparations until pH 6.0 or higher is attained.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of four pancreatic extracts in cystic fibrosis.

Four different pancreatin products, Pancrease, Creon, Pancrex V Forte, and Pancreatin Merck, were compared in a random crossover trial in children with cystic fibrosis. The results of our study showed that patients who received Creon and Pancrease had fewer gastrointestinal symptoms than patients who received Pancrex V Forte and Pancreatin Merck. Fat absorption was significantly improved with Pancrease when compared with Pancrex V forte and Pancreatin Merck. Also the fat absorption with Creon was superior to that with Pancrex V Forte. There was no significant difference in fat absorption between Pancrease and Creon. Pancrex V Forte and Pancreatin Merck, or Pancreatin Merck and Creon. Faecal nitrogen content was less with both Creon and Pancrease compared with Pancreatin Merck. Creon and Pancrease allow the patient with cystic fibrosis to take a high energy diet without any dietary restrictions.

Degradation of cellulose within the gastrointestinal tract in man.

14C-labelled cellulose was administered orally to 10 subjects without gastrointestinal disease and its absorption measured by faecal 14C excretion and 14CO2 in expired air. A mean of 57.2% of oral cellulose was excreted in the faeces and up to 14% (mean 7.5 +/- 4.4 1SD) of faecal radioactivity was water soluble. Whole gut transit time did not correlate with the quantity of 14C-cellulose excreted in the faeces. A significant quantity of 14CO2 appeared in the expired air as early as 30 minutes after administration of the labelled cellulose. The cumulative excretion of 14CO2 varied from 7.6-32.2% of the administered radioactivity but did not correlate with faecal 14C excretion. The present data show that a significant quantity of oral cellulose is metabolised within the human gastrointestinal tract and appears in the expired air as 14CO2.