Prevalence of delayed gastric emptying in diabetic patients and relationship to dyspeptic symptoms: a prospective study in unselected diabetic patients

OBJECTIVE

Data on the prevalence of abnormal gastric emptying in diabetic patients are still lacking. The relation between gastric emptying and dyspeptic symptoms assessed during gastric emptying measurement has not yet been investigated. The aim was to investigate the prevalence of delayed gastric emptying in a large cohort of unselected diabetic patients and to investigate the relation between gastric emptying and gastrointestinal sensations experienced in the 2 weeks before and during the test meal, prospectively.

RESEARCH DESIGN AND METHODS

Gastric emptying was evaluated in 186 patients (106 with type 1 diabetes, mean duration of diabetes 11.6 +/- 11.3 years) using 100 mg (13)C-enriched octanoic acid added to a solid meal.

RESULTS

Gastric emptying was significantly slower in the diabetic subjects than in the healthy volunteers (T(50): 99.5 +/- 35.4 vs. 76.8 +/- 21.4 min, P < 0.003; Ret(120 min): 30.6 +/- 17.2 vs. 20.4 +/- 9.7%, P < 0.006). Delayed gastric emptying was observed in 51 (28%) diabetic subjects. The sensations experienced in the 2 weeks before the test were weakly correlated with the sensation scored during the gastric emptying test. Sensations assessed during the gastric emptying test did predict gastric emptying to some extent (r = 0.46, P < 0.0001), whereas sensations experienced in the previous 2 weeks did not.

CONCLUSIONS

This prospective study shows that delayed gastric emptying can be observed in 28% of unselected patients with diabetes. Upper gastrointestinal sensations scored during the gastric emptying tests do predict the rate of gastric emptying to some extent and sensation experienced during daily life does not.

Effects of ileal bile salts on fasting small intestinal and gallbladder motility

In the fasting state, gallbladder emptying is related to phase III of the intestinal migrating motor complex. The effects of ileal infusion of mixed taurocholate-phospholipid micelles on fasting small intestinal motility (by a 17-channel catheter with side holes located in duodenum, jejunum and ileum) and gallbladder motility (by ultrasound) were investigated in eight healthy volunteers. After bile salt depletion by cholestyramine, 0.9% NaCl or mixed micelles were infused in the ileum during phase II of the migrating motor complex. Time to onset of subsequent phase III was significantly shorter after infusion of mixed micelles compared with 0.9% NaCl (32 +/- 5 min vs. 60 +/- 5 min, P = 0.01). Distal to the infusion port, numbers of pressure waves and their amplitudes were significantly lower during bile salt infusion compared with 15 min before infusion (11 +/- 6 per 15 min vs. 21 +/- 8 per 15 min, and 2.4 +/- 0.6 kPa vs. 2.8 +/- 0.5 kPa, respectively). Micellar infusions increased fasting gallbladder volumes to 170 +/- 5% of starting volumes (P < 0.0001). In conclusion, ileal infusion of mixed micelles influences the timing of phase III of the intestinal migrating motor complex, inhibits ileal motility and increases fasting gallbladder volumes. These findings may have important consequences for enterohepatic circulation of bile salts.

Accurate separation of vesicles, micelles and cholesterol crystals in supersaturated model biles by ultracentrifugation, ultrafiltration and dialysis

Gel filtration with bile salts at intermixed micellar/vesicular concentrations (IMC) in the eluant has been proposed to isolate vesicles and micelles from supersaturated model biles, but the presence of vesicular aggregates makes this method unreliable. We have now validated a new method for isolation of various phases. First, aggregated vesicles and - if present - cholesterol crystals are pelleted by short ultracentrifugation. Cholesterol contained in crystals and vesicular aggregates can be quantitated from the difference of cholesterol contents in the pellets before and after bile salt-induced solubilization of the vesicular aggregates. Micelles are then isolated by ultrafiltration of the supernatant through a highly selective 300 kDa filter and unilamellar vesicles by dialysis against buffer containing bile salts at IMC values. Lipids contained in unilamellar vesicles are also estimated by subtraction of lipid contents in filtered micelles from lipid contents in (unilamellar vesicle+micelle containing) supernatant ('subtraction method'). 'Ultrafiltration-dialysis' and 'subtraction' methods yielded identical lipid solubilization in unilamellar vesicles and identical vesicular cholesterol/phospholipid ratios. In contrast, gel filtration yielded much more lipids in micelles and less in unilamellar vesicles, with much higher vesicular cholesterol/phospholipid ratios. When vesicles obtained by dialysis were analyzed by gel filtration, vesicular cholesterol/phospholipid ratios increased strongly, despite correct IMC values for bile salts in the eluant. Subsequent extraction of column material showed significant amounts of lipids. In conclusion, gel filtration may underestimate vesicular lipids and overestimate vesicular cholesterol/phospholipid ratios, supposedly because of lipids remaining attached to the column. Combined ultracentrifugation-ultrafiltration-dialysis should be considered state-of-the-art methodology for quantification of cholesterol carriers in model biles.

Gallstones: an intestinal disease?

Current evidence suggests that impaired intestinal motility may facilitate gallstone formation by influencing biliary deoxycholate levels or by modulating interdigestive gall bladder motility (fig 2), although a primary intestinal defect in gallstone pathogenesis has not yet been demonstrated. In the cold war period, most interesting events, from a political point of view, occurred at the border between capitalist and communist systems, near the iron curtain. Similarly, the gall bladder and biliary tract can be viewed as the border between liver and intestinal tract, where many interesting things occur with profound impact on both systems. Combined efforts by researchers in the field of hepatology and gastrointestinal motility should brake down the Berlin wall of ignorance of one of the most common diseases in the Western world.

Single or multiple dose ursodeoxycholic acid for cholestatic liver disease: biliary enrichment and biochemical response

BACKGROUND

Ursodeoxycholic acid (UDCA) improves liver biochemistry in primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Since UDCA acts partly by reducing the intestinal absorption of hydrophobic endogenous bile salts and is poorly absorbed from the intestine, a multiple dose regimen has been advocated. Single dose treatment, on the other hand, may improve compliance.

AIM

The effects of a single or multiple dose regimen on liver enzymes and serum and biliary bile salts composition were evaluated.

METHODS

Twenty-seven patients (19 PSC, 8 PBC), most with early stage disease, received UDCA (10 mg kg-1 day-1) in a single dose at bed time (n = 13) or in three divided gifts with meals (n = 14) over 3 months. Five patients had both treatment regimens in random order with a 1-month wash-out period in between.

RESULTS

Liver biochemistry equally improved in both groups. Biliary enrichment (% UDCA of total bile salts, mean +/- SEM) was 40.1 +/- 2.4 in the single dose group vs 40.8 +/- 2.8 in the multiple dose group (p = NS) and was positively correlated with biochemical improvement (AP: r = 0.47, p = 0.02; GGT: r = 0.58, p = 0.002; ASAT: r = 0.67, p = 0.002; ALAT: r = 0.52, p = 0.01). Biochemical improvement was not correlated with the concentration or %UDCA in serum. Patients participating in the cross-over design had comparable biochemical response and biliary %UDCA during both regimens.

CONCLUSION

Single and multiple dose UDCA have similar effects on liver biochemistry and biliary enrichment in cholestatic liver disease. Biochemical improvement appears to be related to biliary (but not serum) enrichment with UDCA.

Does the HMG-CoA reductase inhibitor pravastatin influence nucleation of cholesterol crystals in supersaturated model bile?

OBJECTIVE

To assess whether the presence in bile of HMG-CoA reductase inhibitors, which are secreted predominantly into the bile, influences biliary lithogenicity.

DESIGN

Physiologic biliary concentrations of the hydrophilic HMG-CoA reductase inhibitor pravastatin were added to supersaturated model bile (cholesterol saturation index 1.4) and vesicles, the latter with and without the concomitant addition of the nucleation-promoting bile salt taurodeoxycholate.

OUTCOME MEASURES

Nucleation time, defined as the number of days after which cholesterol monohydrate crystals are visible by phase contrast microscopy in filtered samples of model bile and vesicles, was assessed.

RESULTS

The addition of pravastatin 0.01-1 mg/ml did not influence the nucleation time of supersaturated model bile (mean nucleation time without pravastatin: 8.3 +/- 2.2 days (SD), with pravastatin 1 mg/ml 9.3 +/- 0.4 days and pravastatin 0.01 mg/ml 7.6 +/- 2.3 days). The addition of similar concentrations of pravastatin to vesicle fractions alone did not influence nucleation time (> 20 days), nor could it prevent the nucleation-promoting effect of taurodeoxycholate (nucleation time with or without pravastatin 1 day).

CONCLUSION

The results from this in-vitro study indicate that the presence of pravastatin in bile may not influence gallbladder bile lithogenicity. It can be hypothesized that this also applies to other HMG-CoA reductase inhibitors.

Effect of bile salts on in vitro gallbladder motility: preliminary study

Impaired postprandial gallbladder emptying may be an important factor in cholesterol crystals precipitation and subsequent gallstone formation. We previously found strongly increased bile salt concentrations in gallbladder bile of gallstone patients with weak (< 50% fasting volume) postprandial gallbladder contraction compared to patients with strong (> 50%) postprandial contraction. Therefore, we studied potential effects of various conjugated and unconjugated bile salts with different relative hydrophobicity on in vitro contractility of gallbladder muscle strips obtained at cholecystectomy. Strips were incubated 5 min with bile salt at concentrations of 10(-8)-10(-4)M. The effect of 10(-3)M acetylcholine was measured and related to preincubation control value. Bile salts used were, in order of increasing hydrophobicity: tauroursodeoxy-, ursodeoxy-, tauro-, taurodeoxy- and deoxycholate. Ursodeoxy- and tauroursodeoxycholate did not significantly reduce gallbladder contractility. Taurocholate significantly reduced contractility at concentrations of 10(-6) M and higher, taurodeoxycholate at 10(-7) M and higher and deoxycholate at 10(-5) M and higher. Contractility induced by acetylcholine 10(-3) M at a bile salt concentration of 10(-4) M was 66.0 +/- 11.7% (taurocholate), 50.2 +/- 6.2% (deoxycholate) and 44.8 +/- 11.5% (taurodeoxycholate) of control. The effect of bile salts correlated with their relative hydrophobicity (r = -0.97; p < 0.01). Suppressing effects on gallbladder muscle strip contractility were long lasting and remained after rinsing. Results show that bile salts in the physiological dose range inhibit in vitro gallbladder contraction. If this mechanism exists in vivo, it may have important implications for gallbladder motility regulation.

Tauroursodeoxycholic acid, ursodeoxycholic acid and gallbladder motility in gallstone patients and healthy subjects

Fasting and postprandial gallbladder volumes have been measured by sonography both in healthy subjects and gallstone patients ingesting: (a) tauroursodeoxycholic acid; (b) ursodeoxycholic acid; (c) placebo. Each bile salt was given at a dose of 10 mg kg-1. Sonography was repeated in gallstone patients fed tauroursodeoxycholic acid or ursodeoxycholic acid (10 mg kg-1 day-1) for 1 month. Gallstone patients had gallbladder stasis (increase in fasting and residual volumes) and decreased postprandial emptying. Acute ingestion of tauroursodeoxycholic acid or ursodeoxycholic acid did not modify postprandial gallbladder emptying in both groups of subjects. After one month's therapy with tauroursodeoxycholic acid or ursodeoxycholic acid, fasting gallbladder volume further increased in gallstone patients, although gallbladder emptying remained unchanged. Thus, therapeutic doses of tauroursodeoxycholic acid or ursodeoxycholic acid do not acutely modify postprandial gallbladder emptying in either healthy subjects or gallstone patients. Chronic treatment with either bile salts results in an increase in fasting gallbladder volume without interfering with the extent of postprandial gallbladder emptying.

Effects of simvastatin and cholestyramine on bile lipid composition and gall bladder motility in patients with hypercholesterolaemia

Although the effects of 3-hydroxy, 3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors and bile acid sequestrants on bile lipid composition have been studied separately, no data are available on combination therapy of these drugs. Moreover, the effects of prolonged (four weeks) administration of these drugs on gall bladder motility, an important determinant of cholesterol gall stone formation, have not been studied so far. A prospective study was therefore performed with eight patients who had hypercholesterolaemia (age 53 (5) (SEM), body mass index 27.4 (1.1) kg m-2, low density lipoprotein cholesterol 5.9 (0.3) mmol/l). They received treatment during three periods of four weeks with simvastatin 20 mg/day, cholestyramine 4 g twice daily, and a combination of both in random order, each treatment period separated by a two week wash out period. Before treatment and after each treatment period, postprandial gall bladder motility was studied with ultrasound, followed by duodenal bile sampling. Serum cholesterol decreased in all subjects in any treatment period illustrating good compliance. Molar percentages in duodenal bile of cholesterol, phospholipids, and bile salts were unchanged during simvastatin and cholestyramine treatment. During combined therapy percentage bile salts was lower (72.5 (2.9)% v 77.8 (1.7)% at baseline, p < 0.05) whereas phospholipids were higher (21.2 (2.4)% v 16.4 (1.3)% at baseline, p < 0.05). As a result cholesterol saturation index (CSI) did not change in any treatment period. No cholesterol crystals were detected in any bile sample, taken at baseline and after each treatment period. Bile salt hydrophobicity index during cholestyramine (0.19 (0.02)) and combined treatment (0.22 (0.01)) decreased strongly compared with baseline (0.34 (0.01), p < 0.001, p < 0.01, respectively), resulting from increased proportions of glycocholate (59.4 (3.9)% (cholestyramine), 55.6 (2.4)% (combination), and 28.2 (2.2) (baseline), p < 0.001)) and decreased proportions of deoxycholic acid and chenodeoxycholic acid. Fasting gall bladder volume was increased during simvastatin (28.7 (2.8) ml) v baseline (23.2 (2.3) ml, p < 0.01) whereas, residual volume did not differ (5.7 (0.9) ml (simvastatin) v 5.9 (0.7) (baseline). During cholestyramine and combined treatment, no significant differences in gall bladder motility were seen. In conclusion, this study suggests that HMG-CoA reductase inhibitors alone and combined with cholestyramine do not affect major determinants of cholesterol gall stone formation, for example, CSI and gall bladder emptying. In addition cholestyramine alone and combined with simvastatin leads to a strong decrease of bile salt hydrophobicity, which may be beneficial in the prevention of nucleation of cholesterol crystals.

Effects of cholestyramine on gallbladder and gastric emptying in obese and lean subjects

Gallbladder stasis is frequent in obese subjects and may contribute to their increased risk for gallstone formation. The bile salt sequestrant cholestyramine acutely enhances postprandial gallbladder emptying in lean subjects, through disinhibition of a negative feedback between intraluminal bile salts and CCK release. In this study the effect of cholestyramine on both gallbladder and gastric antrum dynamics were studied by real-time ultrasonography in 12 obese and 15 lean subjects. For the acute study, on different days, subjects ingested a liquid meal (two egg yolks plus water 200 mL, 50 kJ) or a meal with 4 g cholestyramine. Gallbladder emptying was impaired in obese patients who had significantly larger fasting gallbladder volume (39.4 +/- 6.9 vs. 21.6 +/- 1.7 mL, P < 0.02), larger residual volume (12.3 +/- 1.8 vs. 4.0 +/- 0.5 ml, P < 0.0006) and slower emptying time (T/2: 33 +/- 2 vs. 21 +/- 2 min, P < 0.05) than lean subjects. Integrated antral emptying was also less in obese than lean subjects (5521 +/- 578 vs. 7908 +/- 491 %120 min-1, P < 0.02). Cholestyramine enhanced postprandial gallbladder emptying in both obese and lean subjects. Gastric emptying was delayed with cholestyramine in lean but not obese subjects. For the chronic study, after 1 month therapy with cholestyramine (4 g every 2 days), the motility tests were repeated in nine obese subjects. Gallbladder and gastric responses to a test meal, with or without cholestyramine, were preserved. We conclude that both gallbladder and antral emptying of a liquid test meal are impaired in obese subjects. Gallbladder emptying improves after acute administration of a low dose cholestyramine with test meal. This effect is sustained after 1 month treatment with a low dose of cholestyramine and does not interfere with gastric emptying of obese patients. Cholestyramine may improve gallbladder hypomotility in obese people.

Gastric myoelectrical activity and gastrointestinal motility in patients with functional dyspepsia

The aim of our study was to examine the prevalence of gastric myoelectrical disturbances in relation to gastrointestinal motility abnormalities in patients with functional dyspepsia, using simultaneous electrogastrography and antroduodenojejunal manometry. We carried out electrogastrography in 20 patients with functional dyspepsia and in 20 healthy volunteers. In 10 of these patients and in 10 of the volunteers antroduodenojejunal manometry was performed simultaneously. Apart from a higher postprandial power content of the 3 cycles per minute (cpm) component in the patients (1263 +/- 317 and 393 +/- 101 microV2, respectively; P = 0.016), no differences in the electrogastrographic variables were found between the groups. In the manometric part of the study, postprandial antral hypoactivity was not a prominent finding. Instead, small intestinal hyperactivity was found in the dyspeptic patients, with both a higher frequency and amplitude of the contractions (P < 0.05). This hyperactivity often consisted of bursts, which were significantly more frequent in patients than in control subjects (total duration of burst activity 25.6 +/- 6.4 and 6.0 +/- 1.7 min, respectively; P = 0.013). A positive correlation was found between the frequency of the gastric electrical control activity and the antral contraction frequency (P = 0.006), between the power content of the electrographic signal and the antral contraction amplitude (P = 0.025), and between the postprandial/fasting electrographic power ratio and the antral motility index (P = 0.007). In conclusion, gastric myoelectrical activity is minimally disturbed in patients with functional dyspepsia. Motor abnormalities, especially small intestinal hyperactivity, are more likely to play a prominent role in the genesis of dyspeptic symptoms.

The symptom-association probability: an improved method for symptom analysis of 24-hour esophageal pH data

BACKGROUND/AIMS

All methods currently used to quantify the temporal relationships between symptoms and episodes of gastroesophageal reflux, as assessed by 24-hour pH monitoring, have major shortcomings. The aim of this study was to develop and validate a simple, all-comprising statistical method to calculate the probability that gastroesophageal reflux episodes and symptoms are associated.

METHODS

The 24-hour pH signal was divided into consecutive 2-minute periods. These periods and the 2-minute periods preceding the onset of symptoms were evaluated for the occurrence of reflux. Fisher's Exact Test was then applied to calculate the probability (P value) that reflux and symptom episodes were unrelated. Finally, the symptom-association probability (SAP) was calculated as (1.0 - P) x 100%. The SAP values found in 184 24-hour esophageal pH tests were compared with the symptom index and the symptom sensitivity index.

RESULTS

Discordance between the SAP and the symptom index was found in 21 patients (11%) and discordance between the SAP and the symptom-sensitivity index in 28 (15%). False-positive and false-negative symptom index values occurred preferentially in patients with small and large numbers of symptom episodes during the test, respectively (P < 0.05).

CONCLUSIONS

The SAP is a single, simple, quantitative measure of the strength of the association between symptoms and reflux episodes that is devoid of the disadvantages inherent to previously used methods.

Gallbladder motility and cholecystokinin release during long-term enteral nutrition in patients with Crohn's disease

BACKGROUND

Gallbladder bile stasis during long-term continuous enteral feeding may contribute to the high prevalence of gallstones in patients with Crohn's disease. We therefore examined the effects of continuous enteral nutrition on gallbladder motility and cholecystokinin (CCK) release in six patients.

METHODS

Gallbladder volume was measured ultrasonographically for 12 h on days 1 (start), 8, 22 (6-h interruption of enteral feeding), 36, and 43 (end) of enteral feeding. Plasma CCK was assessed at several time points.

RESULTS

Initial fasting gallbladder volume was 19.3 +/- 4.5 (mean +/- SEM) ml, which decreased to 4.9 +/- 3.6 ml after start of feeding. CCK increased from 1.5 +/- 0.3 to 3.9 +/- 1.1 pmol/l. On days 8 and 36 the gallbladder was almost completely contracted, and CCK increased to 7.5 +/- 2.7 and 8.3 +/- 2.6 pmol/l, respectively. On days 22 and 43 gallbladder volume increased, and CCK decreased rapidly to fasting concentrations after interruption of feeding.

CONCLUSIONS

During continuous enteral nutrition the gallbladder is completely contracted, and CCK concentrations remain elevated. It is therefore unlikely that long-term enteral nutrition contributes to the increased prevalence of gallstones in patients with Crohn's disease.

Influence of age on cerebral potentials evoked by oesophageal balloon distension in humans

The recording of viscerosensory cerebral evoked potentials is a new field in the research on gastrointestinal perception. The aim of our study was to assess the relationships between age and peak amplitudes and latencies of cerebral potentials evoked by balloon distension of the human oesophagus. In 16 healthy volunteers (aged 21-59 years), cerebral evoked potentials were recorded from a midline scalp electrode, using a series of 50 rapid balloon inflations with 13 ml of air. Peak to peak amplitudes (N1-P1, P1-N2) and peak latencies (N1, P1, N2) were assessed. Inverse correlations were found between age and N1-P1 amplitude (P < 0.05), and between age and P1-N2 amplitudes (P < 0.05). N1 and P1 latencies were significantly longer in elderly patients (N1: P < 0.05; P1: P < 0.05). Amplitudes and peak latencies of cerebral potentials evoked by balloon distension of the oesophagus are age-dependent. In cerebral evoked potential studies, patients and healthy controls should be age-matched.

Serum lipids, biliary lipid composition, and bile acid metabolism in vegetarians as compared to normal controls

Since dietary factors have been implicated in various diseases, such as coronary heart disease, gallstone formation and colonic cancer, possibly by affecting cholesterol and bile acid metabolism, we studied serum lipid levels, biliary lipid composition, cholic acid and deoxycholic acid kinetics in a group of young healthy male vegetarians and in age, sex and weight matched control subjects. Daily intake of nutrients was higher with respect to polyunsaturated fatty acids, carbohydrates and dietary fibre in the vegetarian group. Although mean serum lipid levels in the vegetarian were 8-28% lower than in the control subjects, differences were not statistically significant. Biliary lipid and biliary bile acid composition were similar in both groups. Bile acid kinetics, measured after simultaneous injection of [3H]cholic acid and [14C]deoxycholic acid, showed a slightly lower output of cholic acid and a slightly higher input of deoxycholic acid in the vegetarians, this causing a significantly (P less than 0.025) higher 7 alpha-dehydroxylation fraction (input deoxycholic acid divided by synthesis of cholic acid) in the vegetarians. Our results in young males suggest that bile acid conservation is associated with a vegetarian diet, but do not support the supposition that a vegetarian diet reduces deoxycholate formation.

Effects of a standardized wheat bran preparation on biliary lipid composition and bile acid metabolism in young healthy males

The effects of adding bran to the normal diet on biliary lipid composition and bile acid metabolism in a group of young healthy males was studied. A chemically standardized coarse wheat bran product, with serum lipid lowering properties, in a dose of 0.5 kg-1 body weight per day was used. Bran feeding for 4 or 8 weeks did not change biliary lipid and biliary bile acid composition. Faecal bile acid and neutral sterol composition was similar before and after 8 weeks of bran. Bile acid kinetics, measured by double isotope dilution after simultaneous injection of [3H]cholic acid and [14C]deoxycholic acid, showed only minor differences before and during bran ingestion. The most surprising finding was an increase in 7 alpha-dehydroxylation fraction (input of deoxycholic acid divided by synthesis of cholic acid) in six out of seven subjects after 4 weeks of brain and in all four subjects after 8 weeks of bran. In conclusion, the bran product we used is not effective in lowering the biliary cholesterol saturation in healthy young males. Nor does it reduce deoxycholate input in our subjects even after 8 weeks of bran.