Visceral hypersensitivity in inflammatory bowel diseases and irritable bowel syndrome: The role of proteases

Proteases, enzymes catalyzing the hydrolysis of peptide bonds, are present at high concentrations in the gastrointestinal tract. Besides their well-known role in the digestive process, they also function as signaling molecules through the activation of protease-activated receptors (PARs). Based on their chemical mechanism for catalysis, proteases can be classified into several classes: serine, cysteine, aspartic, metallo- and threonine proteases represent the mammalian protease families. In particular, the class of serine proteases will play a significant role in this review. In the last decades, proteases have been suggested to play a key role in the pathogenesis of visceral hypersensitivity, which is a major factor contributing to abdominal pain in patients with inflammatory bowel diseases and/or irritable bowel syndrome. So far, only a few preclinical animal studies have investigated the effect of protease inhibitors specifically on visceral sensitivity while their effect on inflammation is described in more detail. In our accompanying review we describe their effect on gastrointestinal permeability. On account of their promising results in the field of visceral hypersensitivity, further research is warranted. The aim of this review is to give an overview on the concept of visceral hypersensitivity as well as on the physiological and pathophysiological functions of proteases herein.

Lactase persistence versus lactose intolerance: Is there an intermediate phenotype?

BACKGROUND

According to the prevailing theory about the genetic background to lactose intolerance, there are three genotypes but only two adult physiological phenotypes: lactase persistence in individuals with the CT and TT genotypes and lactase non-persistence in individuals with the CC genotype. However, analysis of lactase activity from intestinal biopsies has revealed three distinct levels of activity, suggesting that an intermediate physiological phenotype may exist.

AIM

To assess possible disparities between different genotypes with regard to biomarkers of lactase activity and physical symptoms during an oral lactose load test.

METHODS

A retrospective study using an oral lactose load test (n=487). Concentrations of hydrogen in exhaled air and blood glucose were measured. Afterwards, subjects were asked to provide oral mucosa samples for genotyping and answer a questionnaire (participation rate 56%, n=274).

RESULTS

Mean hydrogen levels in exhaled air at 120min were significantly higher in the CT genotype than in the TT genotype. There was no significant difference in blood glucose levels between the two groups. Reported symptoms, with the possible exception of abdominal pain, were equally prevalent in both groups.

CONCLUSIONS

Subjects with the CT and TT genotypes, hitherto classified as lactase-persistent, differ in their physiological response to lactose intake, indicating differences in phenotype which could have clinical significance.

Milk Intolerance, Beta-Casein and Lactose

True lactose intolerance (symptoms stemming from lactose malabsorption) is less common than is widely perceived, and should be viewed as just one potential cause of cows’ milk intolerance. There is increasing evidence that A1 beta-casein, a protein produced by a major proportion of European-origin cattle but not purebred Asian or African cattle, is also associated with cows’ milk intolerance. In humans, digestion of bovine A1 beta-casein, but not the alternative A2 beta-casein, releases beta-casomorphin-7, which activates μ-opioid receptors expressed throughout the gastrointestinal tract and body. Studies in rodents show that milk containing A1 beta-casein significantly increases gastrointestinal transit time, production of dipeptidyl peptidase-4 and the inflammatory marker myeloperoxidase compared with milk containing A2 beta-casein. Co-administration of the opioid receptor antagonist naloxone blocks the myeloperoxidase and gastrointestinal motility effects, indicating opioid signaling pathway involvement. In humans, a double-blind, randomized cross-over study showed that participants consuming A1 beta-casein type cows’ milk experienced statistically significantly higher Bristol stool values compared with those receiving A2 beta-casein milk. Additionally, a statistically significant positive association between abdominal pain and stool consistency was observed when participants consumed the A1 but not the A2 diet. Further studies of the role of A1 beta-casein in milk intolerance are needed.

Inducible Nitric Oxide Synthase in the Duodenal Mucosa Is Associated with Mast Cell Degranulation in Patients with Functional Dyspepsia

AIM

Functional dyspepsia (FD) is a clinical syndrome with chronic gastroduodenal symptoms without noticeable organic or systemic diseases. According to the Rome III consensus, FD can be subdivided into PDS (postprandial distress syndrome) and EPS (epigastric pain syndrome). Neurotransmitters are involved in the development and pathology of FD. However, the expression profiles of neurotransmitters in FD patients are not clear. This study aimed to investigate the expression profile of neurotransmitters in the duodenal mucosa of FD patients.

METHODS

A total of 48 FD patients treated at our hospital were included in this study: 23 patients with PDS and 25 patients with EPS. Another 21 healthy volunteers served as normal controls. The duodenal mucosa was biopsied with gastroscopy and examined with immunohistochemical staining against serotonin, substance P, inducible nitric oxide synthase (iNOS), and vasoactive intestinal peptide (VIP). Mast cells were identified with toluidine blue staining.

RESULTS

The duodenal iNOS levels were significantly higher in PDS patients than the normal controls (P<0.05). The expression of serotonin, substance P, and VIP did not differ significantly among the groups. Mast cell counts and the percentage of mast cells with degranulation were significantly higher in PDS and EPS patients than normal controls (P<0.001) In addition, iNOS expression levels were positively correlated with percentage of degranulating mast cells (r=0.321, P=0.008).

CONCLUSIONS

In conclusion, duodenal iNOS may be involved in the pathogenesis of PDS.

The effect of oral supplementation with Lactobacillus reuteri or tilactase in lactose intolerant patients: randomized trial

BACKGROUND

Lactase enzyme supplements and probiotics with high beta-galactosidase activity may be valid treatment options for the lactose intolerance. Aim of this study was to assess whether supplementation with tilactase or Lactobacillus reuteri when compared to placebo affects hydrogen breath excretion and gastrointestinal symptoms in lactose intolerant patients during lactose breath test (H,-LBT).

METHODS

Sixty lactose intolerant patients participated in the study and were randomized to three 20 patients-treatment groups: tilactase group (tilactase 15 minutes before control H2-LBT); placebo group (placebo 15 minutes before control H2-LBT); Lactobacillus reuteri group (LR) (LR b.i.d. during 10 days before control H2-LBT). The outcomes were LBT normalization rate, and influences of treatments on both mean maximum hydrogen concentration and clinical score.

RESULTS

LBT normalization rate was significantly higher in tilactase and LR groups with respect to placebo. Tilactase was significantly more effective than LR in achieving LBT normalization (p <0.01). Both significant reduction of mean peak H2 excretion and improvement of the mean clinical score were observed in tilactase and LR groups after treatment with respect to placebo (p <0.0001). Tilactase was significantly more effective than LR in reducing both mean peak hydrogen excretion and mean clinical score.

CONCLUSIONS

In lactose intolerants, tilactase strongly improves both LBT results and gastrointestinal symptoms after lactose ingestion with respect to placebo. Lactobacillus reuteri also is effective but lesser than tilactase. This probiotic may represent an interesting treatment option for lactose intolerance since its use is simple and its effect may last in the time after stopping administration.

The patient with slightly elevated pancreatic enzymes and abdominal complaints

Abdominal complaints in combination with slightly elevated serum pancreatic enzymes represent a classical clinical challenge. These symptoms may be due to coincidental unrelated harmless disorders, benign pancreatic alterations which are fairly easily treatable such as mild acute pancreatitis or uncomplicated chronic pancreatitis. However, serious, often insidious diseases such as pancreatic tumours may also present with this constellation as their first signs. Diagnostic procedures need to be stratified according to acuteness and severity of symptoms. While patients with acute onset of symptoms and severe complaints need immediate and combined laboratory and imaging investigations to allow adequate therapy, chronic and mild complaints usually justify a stepwise diagnostic approach consecutively using abdominal ultrasound, CT/MRI and endoscopic ultrasound as imaging procedures and reserving ERCP for cases which remain unclear or in which interventional therapy is needed. Diagnosis and follow-up are often particularly demanding in patients with cystic tumours of the pancreas. In chronic pancreatitis patients pain therapy and adequate control of pancreatic exocrine insufficiency may pose major problems. Patients with refractory pain may ultimately require surgical intervention. Another important indication for surgery in chronic pancreatitis is suspicion of cancer that cannot be ruled out by dedicated diagnostic procedures. This also applies to cystic tumours of the pancreas, which have a high risk of malignant transformation or may even already represent pancreatic cancer at the time of diagnosis.

Role for protease activity in visceral pain in irritable bowel syndrome

Mediators involved in the generation of symptoms in patients with irritable bowel syndrome (IBS) are poorly understood. Here we show that colonic biopsy samples from IBS patients release increased levels of proteolytic activity (arginine cleavage) compared to asymptomatic controls. This was dependent on the activation of NF-kappaB. In addition, increased proteolytic activity was measured in vivo, in colonic washes from IBS compared with control patients. Trypsin and tryptase expression and release were increased in colonic biopsies from IBS patients compared with control subjects. Biopsies from IBS patients (but not controls) released mediators that sensitized murine sensory neurons in culture. Sensitization was prevented by a serine protease inhibitor and was absent in neurons lacking functional protease-activated receptor-2 (PAR2). Supernatants from colonic biopsies of IBS patients, but not controls, also caused somatic and visceral hyperalgesia and allodynia in mice, when administered into the colon. These pronociceptive effects were inhibited by serine protease inhibitors and a PAR2 antagonist and were absent in PAR2-deficient mice. Our study establishes that proteases are released in IBS and that they can directly stimulate sensory neurons and generate hypersensitivity symptoms through the activation of PAR2.

Histological studies on Hirschsprung's disease and its allied disorders in childhood

BACKGROUND/AIMS

To obtain accurate diagnosis for Hirschsprung's disease (HD) and its allied disorders such as hypoganglionosis (Hypo) and intestinal neuronal dysplasia (IND) in childhood patients with chronic constipation, we studied the histology of childhood patients with refractory constipation accompanied by abdominal distension and pain.

METHODOLOGY

Based on clinical signs and symptoms noted on admission, all of 109 patients (60 males and 49 females, aged 2-15 years with a mean age of 9.8 years) were suspected to have chronic refractory constipation. To obtain accurate histological diagnosis in childhood patients with chronic refractory constipation, we performed rectal biopsies on these patients. Tissue samples were frozen and 12-microm sections were stained with acetylcholinesterase (AChE) by the method of Karnovsky and Roots, and with nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase by the modified Scherer-Singler's method.

RESULTS

On the basis of histological studies using rectal biopsies, 20 cases were diagnosed with Hypo, 5 with HD, 2 with intestinal neuronal dysplasia (IND), and 82 with normal findings. The incidence of normal cases was significantly greater than that of allied disorders of HD including both Hypo and IND (P<0.0001). The incidence of Hypo was also significantly greater than that of Hypo and IND (P<0.01, P<0.0001, respectively). Both HD and IND could be diagnosed by rectal mucosal biopsies with AChE staining. However, accurate diagnosis of Hypo could be made only through examination of the submucosal and myenteric plexuses by NADPH-diaphorase staining in full-thickness rectal specimens.

CONCLUSIONS

We were able to obtain accurate diagnosis of childhood patients with HD and IND by rectal mucosal biopsy with AChE staining. On the other hand, accurate histological diagnosis in patients with Hypo could also be obtained by NADPH-diaphorase staining in full-thickness rectal specimens. That is to say, it is easier for the investigator to detect the cholinergic fiber and ganglion cell in the gut wall using NADPH-diaphorase staining than by using AChE staining.

Abdominal pain and preeclampsia: sonographic findings in the maternal liver

OBJECTIVE

To describe sonographic findings in livers of pregnant women with severe preeclampsia and abdominal pain.

METHODS

Over a 12-month period, we performed serial sonographic examinations on 32 pregnant women with severe preeclampsia and acute right upper quadrant and epigastric pain. On each sonogram we observed the liver size and texture, "periportal halo" sign, gallbladder wall, Glisson capsule thickness, painful compression of the liver and gallbladder, and ascites. The pancreas, spleen, kidneys, and uterus were also studied. Sonography was repeated after delivery.

RESULTS

Initial sonograms showed liver abnormalities in 28 patients. Abnormalities consisted of liver hypertrophy (n = 24), hyperechoic thickening of the periportal area (periportal halo sign; n = 23), striated thickening of the gallbladder wall (n = 27), hyperechoic thickening of the Glisson capsule (n = 11), liver areas of increased echogenicity (n = 11), subcapsular hematoma (n = 1), and subcapsular calcification (n = 1). Probe compression of the liver enhanced abdominal pain (n = 13), whereas the gallbladder was painless in all cases. No gallbladder stones were detected. Ascites (n = 16) and pleural effusion (n = 11) were also present. In no case did we detect abnormalities of the pancreas, kidneys, or spleen. All patients eventually had hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome according to the American College of Obstetricians and Gynecologists classification. In 7 cases, HELLP syndrome developed postpartum. Three patients also had eclampsia. Follow-up sonograms highlighted quick regression of abnormalities after delivery.

CONCLUSIONS

The livers of women with severe preeclampsia who had HELLP syndrome showed sonographic abnormalities before biological abnormalities. Serial sonographic examinations could therefore contribute to the obstetric care of these women. Preeclampsia and HELLP syndrome should be routinely checked for in all pregnant women with acute abdominal pain.

Serum levels of procarboxypeptidase B and its activation peptide in patients with acute pancreatitis and non-pancreatic diseases

BACKGROUND

Carboxypeptidase B from the pancreatic gland may exist in three different molecular and immunoreactive forms: the proenzyme, the active enzyme, and the activation peptide.

AIMS

To investigate levels of procarboxypeptidase B (proCAPB) and its activation peptide in serum in acute pancreatitis to test the accuracy of these two variables as markers for the diagnosis of acute pancreatitis and for prediction of pancreatic necrosis. To elucidate whether leakage of proenzymes and activation of proenzymes reflect two different pathophysiological events in acute pancreatitis.

METHODS

Sera from patients with acute pancreatitis (n=85) and acute abdominal pain of non-pancreatic origin (n=53) were analysed for proCAPB and its activation peptide. Patients with pancreatitis were divided into necrotising (n=33) and oedematous attacks (n=52) using contrast enhanced computed tomography. Accuracy was determined using receiver operating characteristic curve analysis.

RESULTS

Immunoreactive carboxypeptidase B activation peptide (ir-CAPAP) concentration in serum on admission was 0.7 nmol/l (0-18.1) in patients with oedematous pancreatitis compared with 5.8 nmol/l (1.9-34) in patients with later development of pancreatic necrosis. Elevated levels of the activation peptide on admission correlated with an accuracy of 92% to later development of pancreatic necrosis. Ir-proCAPB concentration in serum on admission was 16.0 nmol/l (1.4-50.5) in all patients with acute pancreatitis versus 0.3 nmol/l (0-3.6) in patients with non-pancreatic acute abdominal disorders. Cases with oedematous pancreatitis had ir-proCAPB levels of 15.4 nmol/l (1.4-50.5) versus 19.1 nmol/l (2.7-36.1) in cases with later development of pancreatic necrosis. Measurement of the proenzyme can thus be useful for the diagnosis of acute pancreatitis (accuracy 99%) but levels did not correlate with later development of pancreatic necrosis (accuracy 56%).

CONCLUSION

Leakage of proenzymes occurs in acute pancreatitis, irrespective of severity, while development of pancreatic necrosis occurs only when there is activation of the proenzymes.

Familial hyperamylasemia

A 7-year-old white boy was referred to us with a history of 3 attacks of hypogastric pain over the previous 2 years and persistently elevated serum amylase concentrations. At physical examination, he was well with no evidence of clinical abnormalities. His weight and height were normal. Laboratory diagnostic investigations were all normal except for the presence of Ascaris lumbricoides in the feces and persistently elevated serum amylase levels. Serum amylase determinations in the family members were normal in his father and maternal grandmother but elevated in his mother, sister, maternal aunt, and uncle, all of whom asymptomatic. Macroamylasemia was excluded in the child and in the mother. The finding of persistently elevated amylasemia in the child and in the other family members spanning 3 generations, and the exclusion of diseases that lead to hyperamilasemia are consistent with the diagnosis of familial hyperamylasemia. Until now, only 1 similar case has been reported. Familial hyperamylasemia must be considered in the differential diagnosis of hyperamylasemias in childhood.

Analgesic and anti-inflammatory effects of phosphodiesterase inhibitors

The aim of the present study was to investigate the role of phosphodiesterase (PDE) enzyme inhibitors namely rolipram and theophylline in pain and inflammation in experimental animals. Rolipram, a selective PDE IV inhibitor and theophylline a nonspecific PDE inhibitor exerted dose dependent analgesic and anti-inflammatory effect against acetic acid-induced writhing in mice and carrageenan-induced paw edema in rats, respectively. Nimesulide (1, 2 mg/kg) produced significant anti-inflammatory effect. Further, nimesulide (0.5 mg/kg) potentiated analgesic effect of rolipram but it failed to modulate the anti-inflammatory effect of PDE inhibitors. Present study suggests that PDE enzymes might be playing a role in nociceptive and inflammatory responses in animals.

Macrolipasaemia in a patient with pancreas divisum and acute abdominal pain: a case report

This study describes a rapid increase of serum lipase activity during an episode of severe abdominal pain in a female patient with macrolipasaemia and pancreas divisum. Serum lipase activity was persistently elevated in the patient with simultaneously low levels of amylase activity which only increased in association with endoscopic retrograde cholangiopancreatography. Polyethylene glycol precipitation experiments, as well as the results of exclusion chromatography, demonstrated that the high lipase activity was due to a macromolecule of approximately 200000 Da. Affinity chromatography and immunological investigations further indicated that the atypical time-course of lipase activity was not due to alterations of the patient's lipase, but due to lipase-binding autoantibodies resulting in the formation of immune complexes between lipase and immunoglobulin G lambda. Our results show that macrolipasaemia must be considered as a possible cause in patients with unexplained raised serum lipase activity.

Familial hyperamylasaemia

A six year old boy underwent extensive investigation for recurrent abdominal pain and was found to have a persistently raised serum amylase. Endoscopic retrograde cholangiopancreatography was normal and macroamylasaemia was excluded. Serum amylase concentrations were found to be raised in other family members spanning three generations, all of whom were asymptomatic. Clearance studies suggested no evidence of a renal tubular defect and serum lipase concentrations were normal. This is the first report of apparently familial hyperamylasaemia and the mode of inheritance is consistent with an autosomal dominant pattern.

Changes of protein gene product 9.5 (PGP 9.5) immunoreactive nerves in inflamed appendix

The existence of chronic appendicitis is controversial. In this prospective study, we investigated possible changes in the innervation of the appendix under different pathological conditions and correlated histological findings with clinical observation. Thirty appendectomy specimens and 14 appendices obtained from organ donors or patients who underwent right hemicolectomy were immediately fixed in Bouin's solution and processed for immunocytochemistry using an antiserum directed against the panneuronal marker protein gene product 9.5 (PGP 9.5). The density of PGP 9.5 immunostaining was evaluated by digitized morphometry. Significant differences in the density of the PGP 9.5-immunoreactive area were detected in the mucosal layer. In the nonacute appendicitis group, PGP 9.5 was increased (10.99 +/- 3.15%) as compared to acute appendicitis (3.89 +/- 1.77%) and controls (4.98 +/- 1.25%). The significant increase of PGP 9.5 in nonacute appendicitis may suggest axonal sprouting leading to hyperinnervation of the mucosa. This may be a neuronal factor in the pathophysiology of the disease and pain symptoms.

Serum amylase determinations in pediatric patients presenting to the ED with acute abdominal pain or trauma

The objective of this study was to evaluate the overall impact of serum amylase determinations in the initial management of patients presenting to the pediatric emergency department (ED) with the acute onset of abdominal pain or trauma. All cases of patients younger than 18 years of age who presented to the pediatric ED for whom a serum amylase value was determined during an 18-month period were reviewed. Data were collected retrospectively, including serum amylase concentration, age, gender, presenting complaint, discharge/admission status, diagnosis, and discharge plans or inpatient management to evaluate the impact of serum amylase determinations. Seven hundred twenty-three cases were reviewed during the study period. Six hundred fifty-six patients met study criteria, with 385 serum amylase determinations performed for the evaluation of acute abdominal pain and 271 for acute trauma. Sixty-seven serum amylase determinations were also sent for other reasons. Overall, 12 of 656 study patients had elevated amylase levels (1.8%) during the study period (range, 130 to 2318 U/L). Eight of 271 amylase levels sent to the laboratory for trauma (3.0%), and 4 of 385 sent for abdominal pain (1.0%) were elevated. Overall, serum amylase concentration had no influence on whether or not the patient was admitted to the hospital. Of the 12 patients with elevated amylase levels sent for abdominal pain or trauma, only 2 had their clinical management affected by the serum amylase concentration. In both cases, the patient presented with subacute abdominal pain related to significant abdominal trauma that had occurred 2 to 3 weeks earlier. Both patients showed evidence of pancreatic insult with diagnostic imaging studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum lipase levels in nonpancreatic abdominal pain versus acute pancreatitis

OBJECTIVE

1) To determine whether serum lipase is elevated in patients with nonpancreatic abdominal pain, and 2) to compare the levels of serum lipase and serum amylase found in patients with nonpancreatic abdominal pain with those found in acute pancreatitis in order to differentiate between the two groups.

METHODS

Serum lipase and amylase levels were estimated in 95 patients with nonpancreatic abdominal pain (group A). These levels were then compared with those found in 75 patients with acute pancreatitis (group P).

RESULTS

Serum amylase in group A ranged from 11 to 416 U/L [mean 58 +/- 46 (SD)]. Three patients (3.3%) had raised amylase levels. The maximum elevation noted in this group was 416 U/L. Serum amylase in group P ranged from 124 to 13,000 U/L (mean 1620 +/- 1976). Twenty of the 75 patients (27%) in group P had levels that overlapped those found in group A. The serum lipase in group A ranged from 3 to 680 U/L (mean 111 +/- 101). Ten of the 93 patients (11%) had elevated lipase levels. The maximum elevation noted was roughly 3 times normal (680 U/L). Serum lipase in group P ranged from 711 to 31,153 (mean 6705 +/- 7022). None of the patients in group P had levels that overlapped those found in group A. The sensitivity of a serum lipase level > 3 normal in detecting acute pancreatitis was 100% and the specificity was 99%. The corresponding figures for serum amylase were 72% and 99%, respectively.

CONCLUSION

A serum lipase level > 3 normal has a better diagnostic accuracy than serum amylase in differentiating nonpancreatic abdominal pain from acute pancreatitis.

Plasma amylase estimation in recurrent abdominal pain in children

In a prospective study of 50 children who were admitted on more than one occasion with undiagnosed abdominal pain, the serum amylase was found to be normal in every case. One case of acute pancreatitis was diagnosed in over 8000 admissions. Serum amylase estimation did not contribute to the management of children with recurrent abdominal pain, and acute pancreatitis is so rare that routine amylase estimations cannot be recommended in paediatric surgical practice.

Electrophoretic fractionation of pancreatic lipase

Human pancreatic isolipases were separated by electrophoresis on cellulose acetate membrane. Band visualization by fluorescence detection of NADH produced by beta-oxidation cyclic reaction of fatty acid liberated from 1,2-dilinoleoylglycerol by lipase was achieved by making a two-plate "sandwich" of an electrophoresis plate and a substrate-bearing plate. Two true lipase forms, named L1 and L2 to reflect their electrophoretic migration, were resolved with this method and quantified by densitometry. The procedure was not only simple and rapid but also precise (between-run CV less than 13.5%) and sensitive (detected lipase fractions of less than 2 U/L). L1 (mean 57% of total lipase, SD 19.3%) and L2 (mean 43%, SD 19.3%) lipase forms were found in all normal persons studied. In a preliminary clinical study of 27 emergency room patients, evaluation of the lipase electrophoretic pattern in serum did not separate patients with acute pancreatitis from those with other acute abdominal disorders.

Lipase latex test for acute abdominal pain: comparison with serum lipase, trypsin, elastase and amylase

The diagnostic capacity of a semiquantitative latex test for lipase measurement was compared with the measurement of other pancreatic enzymes in 100 consecutive patients admitted to a general hospital for recent onset of severe abdominal pain. Positive results of the test were found in two patients with acute pancreatitis, and in one out of three chronic pancreatitis relapses. The test yielded false-positive results only in two patients who had no apparent pancreatic involvement. A marginal increase in other pancreatic enzymes was found in a few patients with acute biliary or appendicular problems. In conclusion, the lipase latex test can be suggested in an emergency setting as a quick and reliable alternative to serum amylase to rule out a diagnosis of acute pancreatitis.

Pseudopancreatitis in choledochal cyst in children: intraoperative study of amylase levels in the serum

A case of acute necrotizing pancreatitis in association with choledochal cyst is presented. Pancreatitis associated with choledochal cyst is probably caused by a biliary reflux into the pancreatic duct via a pancreatobiliary malunion, as the intraductal pressure of the cyst exceeds that of the pancreatic duct. Ampullar stenosis due to gallstones or inflammatory changes may increase the intraductal pressure. Bile with activated pancreatic enzymes refluxes into the pancreatic duct, and possibly results in acute pancreatitis. However, patients with choledochal cyst presenting with recurrent bouts of abdominal pain, vomiting, and fever have often been diagnosed as having acute pancreatitis because of hyperamylasemia, despite no evidence of pancreatitis at the time of surgery. At the time of bouts, they also show a slight elevation of serum bilirubin, and an increase in the degree of the choledochal dilatation that are possibly caused by biliary obstruction, not ampullar obstruction, due to suppurative cholangitis. The term "fictitious pancreatitis" or "pseudopancreatitis" in choledochal cyst appears to be appropriate. This clinical study shows that amylase in the biliary tract has ready access to the blood stream, probably through a sinusoidal pathway by cholangiovenous reflux, and a lymphatic pathway, via the Disse's space and denuded cyst wall, provided the biliary ductal pressure is increased.