Gallbladder motility and cholecystokinin secretion in chronic pancreatitis: relationship with exocrine pancreatic function

[COMPOSITION OF GASTRIC JUICE AND BILE IN RATS AT THE EXPERIMENTAL CHRONIC PANCREATITIS]

Chronic pancreatitis is an inflammatory disease of the pancreas, which is characterized by destruction of pancreatic secretory parenchyma and progressing exocrine and endocrine insufficiency. Usually these patients have complications as cardiovascular, renal, respiratory and liver failure, and various gastric dysfunctions. The data of clinical observations do not reveal fully the functional state of the stomach and liver in chronic pancreatitis also remains an open question about the quality of the gastric juices and bile by this pathology. Therefore our aim was to investigate the secretory functions of the stomach and liver features in rats at the experimental chronic pancreatitis. This pathology modeled using L-arginine. Basal gastric secretion was investigated in chronic experiment by aspiration method for 10th and 63rd days, and pancreas and liver--in acute experiments at 13th and 68th days after the last administration of L-arginine. It was established that the character of the secretory response of the digestive tract depends on the duration of the pathology course. On the 10th day the functional state of the gastric secretory glands in rats with chronic pancreatitis characterized by twice increase of gastric acid production but decrease the level of hexosamines on 23.8% (P < 0.001) that indicate a increase of gastric content aggressiveness and mucus producing cells secretory insufficiency. In these animals the rate of total protein decreased on 61.7% (P < 0.05). On the 13th day observed the increase of pancreatic juice on 332% (P < 0.01), hepatic secret volume on 74.9% (P < 0.001) and redistribution in the cholates spectrum: glycocholates level increased but tauro-, free and total dehydroxylated bile acids decreased. These changes suggest deterioration of bile detergent properties, inhibition of acidic pathway of bile acids biosynthesis and conjugation of cholates with taurine. In two months total deficit of amino acids in gastric juice correlated with exocrine pancreatic insufficiency. Herein the acidity of gastric content partially restored, while the level of protein and mucus secretion proceed to decline. Consequently gastric mucosa is more vulnerable. In these rats the rates of free bile acids greatly increased while tauro- and glycocholates significantly decreased. Thus the processes of hydroxylation and conjugation of bile acids with amino acids inhibited suggesting interruption of synthetic and detoxification functions of the liver. The present work is important for comprehension the pathophysiological aspects of chronic pancreatitis particularly the digestive system functioning features at this pathology. These data could be considered in the appointment of treatment to avoid complications.

Enzyme replacement therapy for pancreatic insufficiency: present and future

Pancreatic enzyme replacement therapy is currently the mainstay of treatment for nutrient malabsorption secondary to pancreatic insufficiency. This treatment is safe and has few side effects. Data demonstrate efficacy in reducing steatorrhea and fat malabsorption. Effective therapy has been limited by the ability to replicate the physiologic process of enzyme delivery to the appropriate site, in general the duodenum, at the appropriate time. The challenges include enzyme destruction in the stomach, lack of adequate mixing with the chyme in the duodenum, and failing to deliver and activate at the appropriate time. Treatment is begun when clinically significant malabsorption occurs resulting in steatorrhea and weight loss. Treatment failure is addressed in a sequential fashion. Current research is aimed at studying new enzymes and delivery systems to improve the efficiency of action in the duodenum along with developing better means to monitor therapy.

Delayed release pancrelipase for treatment of pancreatic exocrine insufficiency associated with chronic pancreatitis

Pancreatic enzyme supplements (PES) are used in chronic pancreatitis (CP) for correction of pancreatic exocrine insufficiency (PEI) as well as pain and malnutrition. The use of porcine pancreatic enzymes for the correction of exocrine insufficiency is governed by the pathophysiology of the disease as well as pharmacologic properties of PES. Variability in bioequivalence of PES has been noted on in vitro and in vivo testing and has been attributed to the differences in enteric coating and the degree of micro-encapsulation. As a step towards standardizing pancreatic enzyme preparations, the Food and Drug Administration now requires the manufacturers of PES to obtain approval of marketed formulations by April 2010. In patients with treatment failure, apart from evaluating drug and dietary interactions and compliance, physicians should keep in mind that patients may benefit from switching to a different formulation. The choice of PES (enteric coated versus non-enteric coated) and the need for acid suppression should be individualized. There is no current standard test for evaluating adequacy of therapy in CP patients and studies have shown that optimization of therapy based on symptoms may be inadequate. Goals of therapy based on overall patient presentation and specific laboratory tests rather than mere correction of steatorrhea are needed.

Coordinate regulation of gallbladder motor function in the gut-liver axis

Gallstones are one of the most common digestive diseases with an estimated prevalence of 10%-15% in adults living in the western world, where cholesterol-enriched gallstones represent 75%-80% of all gallstones. In cholesterol gallstone disease, the gallbladder becomes the target organ of a complex metabolic disease. Indeed, a fine coordinated hepatobiliary and gastrointestinal function, including gallbladder motility in the fasting and postprandial state, is of crucial importance to prevent crystallization and precipitation of excess cholesterol in gallbladder bile. Also, gallbladder itself plays a physiopathological role in biliary lipid absorption. Here, we present a comprehensive view on the regulation of gallbladder motor function by focusing on recent discoveries in animal and human studies, and we discuss the role of the gallbladder in the pathogenesis of gallstone formation.

Gallstone disease: Symptoms and diagnosis of gallbladder stones

The clinical aspects and the diagnostic features of gallstone disease are described. The natural history of silent gallstones is overviewed, and the risk of developing symptoms and complications is also discussed. The importance of colicky pain as a specific gallstone symptom is highlighted, and the role of both laboratory tests and diagnostic investigations for differential diagnosis is discussed. Finally, we describe the diagnostic features of gallbladder stone disease, including indications, sensitivity, specificity, and limitations of different test investigations under special circumstances.

Pancreatic enzyme supplement improves dysmotility in chronic pancreatitis patients

BACKGROUND AND AIMS

Impaired gallbladder contraction and rapid gastric emptying in patients with chronic pancreatitis may be the result of depleted pancreatic exocrine function. The authors tested whether oral pancreatic enzymes can improve the dysmotility or not.

METHODS

Study subjects consisted of 15 patients with chronic pancreatitis and 18 healthy controls. The gastric emptying time and gallbladder contraction were studied. All patients were initially studied using a test meal without pancreatic enzymes, followed on separate days by a test meal with a single and a triple dose of pancreatic enzymes. Blood samples were taken before and 2 h after the test meal to determine the pancreatic polypeptide levels.

RESULTS

In patients with chronic pancreatitis, gallbladder contraction at 15 min after the meal was impaired. The gastric emptying time was faster and the ratio of pre- to postprandial pancreatic polypeptide levels was enhanced. A single dose and a triple dose of oral enzymes further improved the gastric emptying time and the pancreatic polypeptide ration, but did not improve the gallbladder contraction rate at 15 min.

CONCLUSIONS

It was demonstrated that the oral pancreatic enzymes improved the gastric dysmotility, confirming the previous findings that suggested the depleted pancreatic enzyme output caused the dysmotility.

An enteral therapy containing medium-chain triglycerides and hydrolyzed peptides reduces postprandial pain associated with chronic pancreatitis

BACKGROUND/AIM

Pain in patients with chronic pancreatitis is difficult to manage. We examined if an enteral formulation containing medium-chain triglycerides (MCT) and hydrolyzed peptides would (1) minimally stimulate the exocrine pancreas by blunting cholecystokinin release and (2) decrease pain in patients with chronic pancreatitis.

METHODS

In the first part of the study, on separate days, 6 healthy controls consumed a standard enteral formulation, an enteral formulation containing MCT and hydrolyzed peptides, and a high-fat meal. Baseline and postprandial plasma cholecystokinin (CCK) concentrations were analyzed. Subsequently, 8 patients with chronic pancreatitis were enrolled and instructed to complete a visual analog pain assessment for a baseline period of 2 weeks followed by three cans per day of the enteral formulation containing MCT and hydrolyzed peptides for 10 weeks.

RESULTS

Mean CCK levels for our control subjects were 0.46 +/- 0.29 pM at baseline, 10.75 +/- 0.45 pM in response to the high-fat meal, and 7.9 +/- 1.25 pM in response to the standard enteral formulation. Of note, CCK levels were 1.43 +/- 0.72 pM in response to the enteral supplement containing MCT and hydrolyzed peptides. In patients with chronic pancreatitis, the average improvement in pain scores from baseline to the conclusion of the study was 61.8% (p = 0.01). This corresponded to a clinical improvement in 6 of the 8 patients.

CONCLUSIONS

A complete enteral supplement containing MCT and hydrolyzed peptides minimally increases plasma CCK levels. This therapy may be effective in reducing postprandial pain associated with chronic pancreatitis.

Methods of measuring gallbladder motor functions--the need for standardization: scintigraphy

Emptying the gallbladder is part of the complex process of food digestion. The gallbladder interacts with other gastrointestinal organs and its movements are coordinated and modified by functions of the stomach, intestine and pancreas. Many factors can modify gallbladder motility, for example, sex and age of the subject, their body mass, the kinds of food ingested and stimulus used. The assumption that the gallbladder progressively empties during meals and refills during fasting is incorrect. Using a combination of ultrasonography and cholescintigraphy, it is possible to measure absolute and net gallbladder emptying. In this way we demonstrated that the gallbladder begins to refill immediately after emptying begins, and the difference between net and absolute emptying of the gallbladder indicates the refilling of bile and provides a measure of bile turnover rate, an accurate index to assess gallbladder motility.

Pathophysiological role of cholecystokinin in humans

Cholecystokinin (CCK) is a major gastrointestinal hormone that plays an important role in stimulation of pancreatic secretion and gall-bladder contraction, regulation of gastrointestinal motility and induction of satiety. Ingestion of fat and protein induces significant increases in plasma CCK. Intraluminal mediators of CCK secretion, luminal CCK releasing factor and diazepam-binding inhibitor, were purified from rat intestinal secretion. These CCK-releasing factors (RF) are secreted tonically by the small intestine and stimulate CCK release. Another kind of CCK-RF named 'monitor peptide' was purified from the rat pancreatic juice that stimulates CCK secretion when introduced into rat intestine. Bile exclusion from the duodenum causes an increase in basal CCK and enhances stimulated plasma CCK release, and bile salt replacement reverses these effects. Thus, the CCK-RF are spontaneously secreted into the intestinal lumen in humans, while the CCK-producing cells are under constant suppression by intraduodenal bile acids. In acute pancreatitis, plasma CCK levels are high in patients with gallstone pancreatitis, but not in patients with pancreatitis from other causes, such as alcoholic and idiopathic pancreatitis. A transient disturbance of bile flow into the duodenum by stones or oedema of the pancreas together with impairment of pancreatic exocrine function might cause the increase in plasma CCK release in gallstone pancreatitis. Patients with chronic pancreatitis with mild to moderate impairment of exocrine function and abdominal pain, had significantly higher plasma CCK concentrations, whereas patients with pancreatic insufficiency had a significantly lower plasma CCK response to a test meal than the healthy subjects. The increased CCK may further aggravate pancreatitis and worsen the prognosis of pancreatitis by stimulating the injured pancreas, resulting in the vicious circle via endogenous CCK release. The CCK-A receptor antagonist might be therapeutically useful in acute pancreatitis by stopping the vicious circle.

Differences in cholecystokinin release and gallbladder contraction between emulsified and nonemulsified long-chain triglycerides

BACKGROUND

Fat is a potent stimulus of cholecystokinin (CCK) release. Apart from lipolysis, fatty acid chain length, and saturation, emulsification may also determine the magnitude of CCK release.

METHODS

We have studied the effect of emulsification of soybean oil on CCK and pancreatic polypeptide (PP) release (radioimmunoassay [RIA]) and gallbladder motility (ultrasonography). Six healthy subjects were studied on three separate occasions in random order during (1) intraduodenal administration of emulsified long-chain triglycerides (LCT) (6 mmol/h for 120 minutes); (2) equimolar amounts of nonemulsified LCT with addition of emulsifier; and (3) saline with emulsifier (control).

RESULTS

Intraduodenal administration of both nonemulsified LCT and emulsified LCT induced significant (p < .05) increases in plasma CCK and PP levels and reductions in gallbladder volume. However, compared with nonemulsified LCT, emulsified LCT resulted in a readier and significantly stronger CCK release (212+/-62 pmol/L per 120 minutes vs 36+/-7 pmol/L per 120 minutes; p < .05); PP release (2034+/-461 pmol/L per 120 minutes vs 671+/-106 pmol/L per 120 minutes; p < .05); and gallbladder contraction (77%+/-2% vs 41%+/-7%; p < .05). No significant alterations were observed in plasma CCK or PP levels and gallbladder volume during administration of saline with emulsifier.

CONCLUSIONS

Intraduodenal administration of a low-dose emulsified LCT more potently stimulates CCK and PP release and gallbladder contraction in comparison to equimolar amounts of nonemulsified LCT. These findings point to an important role for solubilization of LCT in determining the magnitude of CCK release from the intestine.