Pancreaticobiliary Reflux in Patients with and without Cholelithiasis: Is It a Normal Phenomenon?

Age and incidence of occult pancreaticobiliary reflux in patients with benign gallbladder diseases

BACKGROUND

Occult pancreaticobiliary reflux (OPBR) has a significant correlation with diseases of the gallbladder and biliary system. This study examined the incidence of OPBR by age in patients with benign gallbladder diseases.

METHODS

We assessed 475 patients with benign gallbladder diseases who underwent surgery at Shanghai East Hospital from December 2020 to December 2021. Bile samples collected during surgery were tested for amylase. Patients with bile amylase >110 U/L (n = 64) were classified as the OPBR group; the rest (n = 411) as controls.

RESULTS

Of the participants, 375 had gallbladder stone (GS), 170 had gallbladder polyp (GP), and 49 had gallbladder adenomyomatosis (GA). The OPBR group was generally older, with OPBR incidence increasing with age, peaking post-45. Rates by age were: 4.9% (<35), 5.2% (35-44), 20.7% (45-54), 22.5% (55-64) and 17.6% (≥65), mainly in GS patients. ROC analysis for predicting OPBR by age yielded an area under the curve of 0.656, optimal cut-off at 45 years. Logistic regression indicated age > 45, GP, male gender, and BMI ≥ 24 kg*m-2 as independent OPBR predictors in GS patients. Based on these variables, a predictive nomogram was constructed, and its effectiveness was validated using the ROC curve, calibration curve and decision curve analysis (DCA). Further stratification revealed that among GS patients ≤ 45, concurrent GA was an OPBR risk; for > 45, it was GP and male gender.

CONCLUSIONS

The incidence of OPBR in GS patients is notably influenced by age, with those over 45, especially males without GP, being at heightened risk.

Identification of changes in bile composition in pancreaticobiliary reflux based on liquid chromatography/mass spectrometry metabolomics

INTRODUCTION

Pancreaticobiliary reflux (PBR) can induce gallstone formation; however, its pathogenic mechanism remains unclear. In this study, we explored the mechanism of PBR by the non-targeted metabolomic analysis of bile in patients with PBR.

OBJECTIVE

The aim of this study was to investigate the pathogenic mechanism in PBR by the non-targeted metabolomic analysis of bile collected during surgery.

METHODS

Sixty patients who underwent gallstone surgery at our center from December 2020 to May 2021 were enrolled in the study. According to the level of bile amylase, 30 patients with increased bile amylase ( > 110 U/L) were classified into the PBR group, and the remaining 30 patients were classified into the control group (≤ 110 U/L). The metabolomic analysis of bile was performed.

RESULTS

The orthogonal projections to latent structure-discriminant analysis of liquid chromatography mass spectrometry showed significant differences in bile components between the PBR and control groups, and 40 metabolites were screened by variable importance for the projection value (VIP > 1). The levels of phosphatidylcholine (PC) and PC (20:3(8Z,11Z,14Z)/14:0) decreased significantly, whereas the levels of lysoPC (16:1(9z)/0:0), lysoPC (15:0), lysoPC (16:0), palmitic acid, arachidonic acid, leucine, methionine, L-tyrosine, and phenylalanine increased.

CONCLUSIONS

Significant differences in bile metabolites were observed between the PBR and control groups. Changes in amino acids and lipid metabolites may be related to stone formation and mucosal inflammation.

Occult pancreaticobiliary reflux is a pathogenic factor of some benign biliary diseases and gallbladder cancer

BACKGROUND

Pancreaticobiliary maljunction (PBM) is a well-known high-risk factor for biliary malignant tumors because of constant pancreaticobiliary reflux (PBR). However, the impact of occult pancreaticobiliary reflux (OPR), which is characterized by high bile amylase levels in individuals with anatomically normal pancreaticobiliary junction, on biliary diseases remains unclear. The aim of this study was to assess the correlation between OPR and biliary diseases.

METHODS

We enrolled 94 consecutive patients with normal pancreaticobiliary junction and primary biliary diseases confirmed by magnetic resonance cholangiopancreatography. We prospectively collected patients' bile samples and measured bile amylase levels. We investigated the incidence of OPR and the difference in bile amylase levels among these patients and assessed the correlation between high bile amylase levels (HBAL) and benign or malignant biliary diseases, as well as the OPR risk factors.

RESULTS

The incidence of OPR was 36.6% in patients with benign biliary diseases, 26.7% in those with cholangiocarcinoma and 62.5% in those with gallbladder cancer. The median bile amylase level tended to be higher in patients with gallbladder cancer than in those with benign biliary diseases, but there was no significant difference (165.5 IU/L vs. 23.0 IU/L, P = 0.212). The prevalence of an HBAL with bile amylase levels of 1000-7500 IU/L was similar in patients with gallbladder cancer and benign biliary diseases. However, the incidence of HBAL with bile amylase levels greater than 7500 IU/L was significantly higher in patients with gallbladder cancer than in those with benign biliary diseases (37.5% vs. 4.2%, P = 0.012). Multivariate logistic regression analysis revealed that choledocholithiasis was an independent risk factor for OPR.

CONCLUSIONS

OPR can occur in benign and malignant biliary diseases, and it may be a pathogenic factor for some benign biliary diseases and a high-risk factor for gallbladder cancer. There is a correlation between choledocholithiasis and OPR.

Free fatty acids and triglyceride change in the gallbladder bile of gallstone patients with pancreaticobiliary reflux

Background

Pancreaticobiliary reflux (PBR) causes chronic inflammation of the gallbladder mucosa and changes in the bile components, which are known to promote gallstone formation. This study aimed to investigate the bile biochemistry changes in gallstone patients with PBR and provide new clues for research on the involvement of PBR in gallstone formation.

Methods

Patients undergoing surgery for gallstones between December 2020 and May 2021 were eligible for inclusion. The bile biochemistry (including amylase, lipase, triglyceride, cholesterol, free fatty acids [FFAs], alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase [ALP], and γ-glutamyl transferase [γ-GT]) of the included gallstone patients was analysed to determine correlations with PBR.

Results

In this study, 144 gallstone patients who underwent surgery were enrolled. Overall, 15.97 % of the patients had an increased bile amylase level, which was associated with older age and significantly higher bile levels of ALP, lipase, triglyceride, and FFAs. Positive correlations were observed between amylase and lipase, triglyceride, FFAs levels in the gallbladder bile. However, the bile levels of triglyceride, FFAs, and lipase were positively correlated with each other only in the PBR group and showed no significant correlation in the control (N) group. In addition, elevated bile FFAs levels were found to be an independent risk factor for gallbladder wall thickening.

Conclusions

In conclusion, PBR-induced increase in FFAs and triglyceride in the gallbladder bile is a cause of gallstone formation, and an increase in bile ALP suggests the presence of cholestasis in PBR.

Common bile duct pressure in patients with and without cholelithiasis: A case-control study

BACKGROUND

The reflux of pancreatic enzymes into the bile duct and the gallbladder is an abnormal phenomenon that plays a role in lithogenesis and carcinogenesis. Because the pressure of the common bile duct depends on the pressures of the sphincter of Oddi, its dysfunction would be reflected in an increase in the pressure of the common bile duct in patients with cholelithiasis. The objective of this study was to measure the pressures of the common bile duct in patients with and without cholelithiasis and to relate them to the presence of pancreatobiliary reflux.

METHODS

A prospective case-control study was designed. The study universe was constituted by all patients undergoing total gastrectomy for gastric cancer stages I and II over 30 months. The primary outcome measure was to establish differences between common bile duct pressures in patients with and without cholelithiasis.

RESULTS

Common bile duct pressures in patients with gallstones showed a significant elevation (16.9 mmHg) compared to patients without gallstones (3.3 mm Hg) (p < 0.0001). These pressures correlated with the levels of amylase and lipase in gallbladder bile; higher levels were found in patients with gallstones compared to patients without gallstones (P < 0.0001).

CONCLUSIONS

Common bile duct pressure in patients with cholelithiasis was significantly higher compared to patients without cholelithiasis leading to pancreatobiliary reflux.

Common bile duct stones associated with pancreatobiliary reflux and disproportionate bile duct dilatation

Occult pancreatobiliary reflux (PBR) in patients with a normal pancreatobiliary junction has been studied by various methods, but the exact etiology, mechanisms, and implications of this reflux have not yet been clarified. The aim of this study was to investigate the degree of PBR and patterns of biliary ductal dilatation in patients with acute calculous cholangitis by endoscopic retrograde cholangiopancreatography (ERCP).We retrospectively evaluated the degree of PBR and pattern of bile duct dilatation in patients with acute calculous cholangitis due to distal CBD (common bile duct) stones (Group A) as compared with patients with malignant CBD obstruction due to distal CBD cancer (Group B). All related data were prospectively collected. Bile juice was aspirated at the proximal CBD for measurement of biliary amylase and lipase before the injection of contrast dye. The diameters of the CBD and the peripheral intrahepatic duct (IHD) were calculated after contrast dye injection. Patients with pancreatobiliary maljunction and/or gallstone pancreatitis were excluded from the study.ERCP was performed on 33 patients with calculous cholangitis (Group A) and 12 patients with malignant CBD obstruction (Group B). Mean levels of bile amylase and lipase were significantly higher (P < .05) in group A (1387 and 6737 U/l, respectively) versus those in group B (32 and 138 U/l, respectively). Thirty patients in group A (90.9%) showed disproportionate dilatation (i.e., CBD was and IHD was not dilated), whereas only 4 patients in group B (33%) showed disproportionate dilatation.The results of this study suggest that patients with calculous cholangitis exhibit PBR that is associated with disproportionate bile duct dilatation.

Clinical significance of bile reflux into the pancreatic duct without pancreaticobiliary maljunction assessed by intraoperative cholangiography

INTRODUCTION

Bile reflux into the pancreatic duct (BRPD) is sometimes demonstrated during intraoperative cholangiography (IOC) even in patients without pancreaticobiliary maljunction. However, the clinical significance of this finding in laparoscopic and open cholecystectomy is unclear.

METHODS

Among 484 patients who underwent cholecystectomy (372 laparoscopic, 112 open), patients whose pancreatic duct was depicted in IOC were selected. The value of pancreatic amylase (p-amylase) of the gallbladder bile, histological changes, and the immunohistochemical expression of proliferating cell nuclear antigen (PCNA) in the gallbladder mucosa were analyzed in patients with BRPD. The data were then compared to those in patients without BRPD whose gallbladder bile p-amylase was measured (control group, n = 20).

RESULTS

The success rate of IOC was 93.6%. The rate of BRPD in laparoscopic and open cholecystectomy was 5.2% and 5.7%, respectively. The value of gallbladder bile p-amylase in patients with BRPD was significantly higher than in the control group (790.5 vs 14.0 IU/L, P = 0.034). The value of the PCNA labeling index in patients with BRPD was significantly higher than that of the control group (15.4% vs 4.1%, P = 0.0026). Among the 24 patients with BRPD, pathological changes in the gallbladder mucosa were detected in five (two hyperplasia, three metaplasia), but there was no correlation between the presence of pathological change and PCNA labeling index or gallbladder bile p-amylase.

CONCLUSIONS

IOC could detect BRPD both in laparoscopic and open cholecystectomy at a similar rate. Patients with BRPD had high levels of gallbladder bile p-amylase and PCNA labeling index, findings similar to those in patients with pancreaticobiliary maljunction.

Many faces of pancreaticobiliary reflux

Pancreaticobiliary reflux may occur either as a result of an anatomically abnormal pancreaticobiliary junction or because of a functionally impaired sphincter despite a normal radiological appearance. It is associated with a wide spectrum of biliary diseases, including gall bladder and bile duct carcinoma. Pancreaticobiliary maljunction and related biliary reflux have been studied extensively in Southeast Asian populations and associations with choledochal cyst and biliary malignancy defined. However, reflux in the absence of ductal malunion has only been described relatively recently and its significance with respect to biliary malignancy requires clarification. We present four cases of pancreaticobiliary reflux to demonstrate the varied associations of this under-recognized disorder and review the related management issues.

Current knowledge on pancreaticobiliary reflux in normal pancreaticobiliary junction

Knowledge on pancreaticobiliary reflux in normal pancreaticobiliary junction and their pathologic implications has experienced tremendous progress during the last few years. This article reviews the current knowledge on this condition and its pathological implications on gallbladder diseases. Many publications with different levels of evidence were found supporting biliary carcinogenesis associated with pancreaticobiliary reflux in normal and abnormal pancreaticobiliary junction. Also, there are many publications supporting the common occurrence of pancreaticobiliary reflux in normal pancreaticobiliary junction, and sphincter of Oddi dysfunction as the most plausible cause of this condition. Although an important body of research has been published regarding pancreaticobiliary reflux in normal pancreaticobiliary junction and their clinical significance, the current evidence does not fully support what has been suggested. The reflux of pancreatic enzymes into the bile tract and gallbladder is a fascinating subject of study which is open to active research. The final demonstration of the pathophysiology and consequences of PBR in NPBL and support by evidence level type I would constitute a major breakthrough in the understanding and eventually in the treatment of gallbladder diseases.

Pancreaticobiliary reflux in patients with a normal pancreaticobiliary junction: Pathologic implications

Knowledge on pancreaticobiliary reflux in normal pancreaticobiliary junction and its pathologic implications has experienced tremendous progress during the last few years. This editorial reviews the current knowledge on this condition and its pathological implications on gallbladder diseases. The following aspects were defined appropriate for discussion: (1) Evidence of carcinogenesis associated with pancreaticobiliary reflux; (2) Evidence of pancreaticobiliary reflux in normal pancreaticobiliary junction; and (3) Evidence of sphincter of Oddi (SO) dysfunction as a cause of pancreaticobiliary reflux in normal pancreaticobiliary junction. The articles reviewed were selected and classified according to five levels of evidence: LevelI, meta-analysis double-blind randomized clinical trials, Level II, cohort non-blinded studies and non-randomized clinical trials, Level III, good quality case-control studies and non-randomized cohort studies, Level IV, case series and poor quality case-control studies, and Level V, case report articles and experts’ opinion. Evidence levels II, III, IV and V were found to support biliary carcinogenesis associated with pancreaticobiliary reflux in normal and abnormal pancreaticobiliary junction. The same levels of evidence were found to support the common occurrence of pancreaticobiliary reflux in normal pancreaticobiliary junction, and SO dysfunction as the most plausible cause of this condition. Although an important body of research has been published regarding pancreaticobiliary reflux in normal pancreaticobiliary junction and its clinical significance, the current evidence does not fully support what has been suggested. Studies with evidence level I have not been undertaken. This is a fascinating subject of study, and if finally supported by evidence level I, the importance of this condition will constitute a major breakthrough in biliary pathology.