Sum P. Lee

Biliary Sludge as a Cause of Acute Pancreatitis

BACKGROUND In about 20 to 40 percent of cases of acute pancreatitis, no cause can be found, and these are labeled idiopathic. In this study, we sought to determine the frequency with which patients with acute idiopathic pancreatitis have biliary sludge, a suspension of cholesterol monohydrate crystals or calcium bilirubinate granules that is found predominantly in the gallbladder. METHODS Between 1980 and 1988, we prospectively studied 86 patients who had acute pancreatitis. In patients with no known cause of pancreatitis and no ultrasonographic evidence of gallstones or dilatation of the biliary ducts, we determined how often biliary sludge was present and its subsequent fate by repeated microscopical examinations of bile samples and abdominal ultrasonography. The outcome of patients treated by cholecystectomy or papillotomy was compared with that of untreated patients. RESULTS The pancreatitis was considered idiopathic in 31 of the 86 patients (36 percent), of whom 23 had microscopical evidence of biliary sludge. Biliary sludge was detected by ultrasonography in only 11 of the 23 patients (48 percent). The sludge detected by ultrasonography was composed of calcium bilirubinate granules in 10 and cholesterol monohydrate crystals in 1 (P = 0.003). Calcium bilirubinate granules were found more frequently in men (nine men vs. four women, P less than 0.001). Of the 21 patients in whom biliary sludge was the only finding (2 patients also had dilasted bile ducts when restudied), the 6 treated by cholecystectomy and the 4 treated by papillotomy had fewer recurrences of acute pancreatitis during follow-up (up to seven years) than the 11 untreated patients (P = 0.011). The presence of biliary sludge appeared to increase the likelihood of recurrent attacks of pancreatitis (P = 0.020). CONCLUSIONS Biliary sludge is an underestimated cause of acute idiopathic pancreatitis.

The prevalence and predictors of elevated serum aminotransferase activity in the United States in 1999-2002.

OBJECTIVES:The presence of elevated serum aminotransferase activity is a sign of possible underlying liver disease. We aimed to describe the prevalence and associations of elevated serum aminotransferase activity in a recent, nationally representative U.S. survey.METHODS:We described the prevalence and predictors of elevated alanine aminotransferase (ALT >43 IU/L) or elevated aspartate aminotransferase (AST >40 IU/L) activity among 6,823 participants of the National Health and Nutrition Examination Survey (NHANES) conducted between 1999 and 2002. We compared our findings to the results already published based on the NHANES conducted between 1988 and 1994.RESULTS:In NHANES 1999–2002, the prevalences of elevated ALT, AST, or either ALT or AST were 8.9%, 4.9%, and 9.8%, respectively, in the entire population and 7.3%, 3.6%, and 8.1%, respectively, after excluding participants who tested positive for hepatitis C virus (HCV) antibody or reported excessive alcohol consumption. Strong predictors of elevated ALT activity included increasing waist circumference and body mass index, alcohol consumption, male sex, Mexican American ethnicity, decreasing age, and presence of HCV antibody. In NHANES 1988–1994, which employed a different assay methodology, the prevalences of elevated aminotransferases were approximately half of the prevalences we describe in NHANES 1999–2002, but the predictors of elevated ALT activity were similar.CONCLUSIONS:The current prevalence of elevated ALT activity in the United States (8.9%) is more than double that of previously available estimates. This prevalence is very high (7.3%) even among persons without viral hepatitis C or excessive alcohol consumption and is strongly associated with risk factors for nonalcoholic fatty liver disease.

Origin and fate of biliary sludge

Biliary sludge is a collection of mucus, calcium bilirubinate, and cholesterol crystals that is usually recognized by characteristic echoes on ultrasonography. Its pathogenesis, clinical significance, and ultimate prognosis remain uncertain. We therefore studied the origin of biliary sludge ultrasonic echoes, using an ex vivo liver-gallbladder preparation, and determined the outcome of a group of patients identified to have gallbladder sludge by ultrasonography. Echoes were not generated by either an increase in the total solid concentration or by the graded addition of partially purified mucus glycoprotein. Cholesterol monohydrate crystals (greater than 50 micron) mixed with mucus produced echoes that were indistinguishable from gallbladder sludge observed in patients. To determine the natural evolution of gallbladder sludge in patients, we prospectively followed 96 patients found to have biliary sludge for a mean of 37.8 mo by serial ultrasound scans every 6 mo. In 17 patients (17.7%) biliary sludge disappeared and did not recur for at least 2 yr, in 58 patients (60.4%) biliary sludge disappeared and reappeared, and in 8 patients (8.3%) asymptomatic gallstones developed. There were 12 cholecystectomies performed: six were done for symptomatic gallstones (6.3%) and the other six for sludge associated with severe biliary pain attacks with or without recurrent acute pancreatitis. The finding of sludge represented precipitates being formed in bile. In some patients, it was a precursor form of gallstone disease.

Elevated serum alanine aminotransferase activity and calculated risk of coronary heart disease in the United States

In the United States, elevated serum alanine aminotransferase (ALT) activity in the absence of viral hepatitis or excessive alcohol consumption is most commonly attributed to nonalcoholic fatty liver disease (NAFLD). NAFLD is related to predictors of coronary heart disease (CHD) such as insulin resistance and central obesity. We examined the association between elevated serum ALT activity and the 10‐year risk of CHD as estimated using the Framingham risk score (FRS). We performed a cross‐sectional analysis comparing participants in the Third National Health and Nutrition Examination Survey with normal and elevated ALT activity (>43 IU/L), examining the mean levels of FRS. Among participants without viral hepatitis or excessive alcohol consumption, those with elevated ALT activity (n = 267) had a higher FRS than those with normal ALT activity (n = 7,259), both among men (mean difference in FRS 0.25, 95% CI 0.07‐0.4; hazard ratio for CHD 1.28, 95% CI 1.07‐1.5) and women (mean difference in FRS 0.76, 95% CI 0.4‐1.1; hazard ratio for CHD 2.14, 95% CI 1.5‐3.0). The ALT threshold for increased risk of CHD was higher in men (>43 IU/L) than in women (>30 IU/L). Elevated ALT activity was not associated with higher FRS among nonobese participants with viral hepatitis or excessive alcohol consumption. In conclusion, individuals with elevated serum ALT activity in the absence of viral hepatitis or excessive alcohol consumption, most of whom have NAFLD, have an increased calculated risk of CHD. This association is more prominent in women. (HEPATOLOGY 2006;43:1145–1151.)

Hepatic Free Cholesterol Accumulates in Obese, Diabetic Mice and Causes Nonalcoholic Steatohepatitis

BACKGROUND & AIMS Type 2 diabetes and nonalcoholic steatohepatitis (NASH) are associated with insulin resistance and disordered cholesterol homeostasis. We investigated the basis for hepatic cholesterol accumulation with insulin resistance and its relevance to the pathogenesis of NASH. METHODS Alms1 mutant (foz/foz) and wild-type NOD.B10 mice were fed high-fat diets that contained varying percentages of cholesterol; hepatic lipid pools and pathways of cholesterol turnover were determined. Hepatocytes were exposed to insulin concentrations that circulate in diabetic foz/foz mice. RESULTS Hepatic cholesterol accumulation was attributed to up-regulation of low-density lipoprotein receptor via activation of sterol regulatory element binding protein 2 (SREBP-2), reduced biotransformation to bile acids, and suppression of canalicular pathways for cholesterol and bile acid excretion in bile. Exposing primary hepatocytes to concentrations of insulin that circulate in diabetic Alms1 mice replicated the increases in SREBP-2 and low-density lipoprotein receptor and suppression of bile salt export pump. Removing cholesterol from diet prevented hepatic accumulation of free cholesterol and NASH; increasing dietary cholesterol levels exacerbated hepatic accumulation of free cholesterol, hepatocyte injury or apoptosis, macrophage recruitment, and liver fibrosis. CONCLUSIONS In obese, diabetic mice, hyperinsulinemia alters nuclear transcriptional regulators of cholesterol homeostasis, leading to hepatic accumulation of free cholesterol; the resulting cytotoxicity mediates transition of steatosis to NASH.

Association between dietary nutrient composition and the incidence of cirrhosis or liver cancer in the united states population

Little is known about the impact of dietary factors on the progression of liver disease. Our aim was to determine whether dietary intake was associated with the risk of cirrhosis‐related or liver cancer–related death or hospitalization in the U.S. population. Participants included 9221 persons aged 25‐74 years without evidence of cirrhosis at entry into the study or during the first 5 years of follow‐up, who were subsequently followed for a mean of 13.3 years as part of the first National Health and Nutrition Examination Survey. Dietary intake was ascertained at baseline using a 24‐hour dietary recall questionnaire. During follow‐up, 123 of 9221 participants had a diagnosis of cirrhosis (n = 118) or liver cancer (n = 5) in hospitalization records or death certificates, including 36 who were diagnosed only on the basis of death certificates. Participants who reported a diet high in protein were at a higher risk of hospitalization or death due to cirrhosis or liver cancer (P = 0.001), whereas those who reported a diet high in carbohydrates were at a lower risk (P = 0.003), after adjusting for potential confounders (daily consumption of protein, carbohydrate, fat, tea or coffee, and alcohol, gender, race, age, educational attainment, U.S. geographical region, diabetes, body mass index, and subscapular‐to‐triceps skinfold ratio). Although total fat consumption was not significantly associated with the risk of cirrhosis or liver cancer, cholesterol consumption was associated with higher risk (P = 0.007), whereas serum cholesterol level was not associated with risk of cirrhosis or liver cancer. Conclusion: Diet may be an important and potentially modifiable determinant of liver disease. (HEPATOLOGY 2009.)

Biliary casts after orthotopic liver transplantation: clinical factors, treatment, biochemical analysis

OBJECTIVES:Biliary casts develop in up to 18% of liver transplant recipients. Casts are associated with morbidity, graft failure, need for retransplantation, and mortality. Proposed etiological mechanisms include acute cellular rejection, ischemia, infection, and biliary obstruction. We aimed to identify clinical features associated with biliary cast formation, review treatments, and analyze the biochemical composition of casts at a single, large, liver transplant center.METHODS:Patient records were reviewed retrospectively to identify patients who developed casts. Data were collected with attention to ischemia, rejection, obstruction, infection, immunosuppression, postoperative biliary drain use, and cast-directed management, and were compared with data from controls. Cast specimens, retrieved at cholangiography, were analyzed with chromatography techniques.RESULTS:Ischemic factors were noted in 70% (7/10) of cast patients versus 15% (6/40) of controls (OR = 13.2; 95% CI = 2.7–66.0; p = 0.001). Biliary strictures were present in 50% of cast patients versus 10% of controls (OR = 9.0; 95% CI = 1.8–45.2; p = 0.01). Differences in cold ischemia time, acute cellular rejection, cyclosporin use, infection, and postoperative biliary drain use were not significant. Casts were successfully treated by endoscopic and percutaneous methods in 60% of patients. One patient died of cast-related complications (mortality 10%). Four casts were in satisfactory condition for biochemical analysis. Bilirubin was the main component (∼10–50%). Bile acid synthesis products and cholesterol comprised smaller percentages, and protein comprised only 5–10%.CONCLUSION:Biliary casts are more likely to develop in the setting of hepatic ischemia and biliary strictures. Endoscopic and percutaneous cast extraction might achieve favorable results and should be attempted before surgical therapy.

Serotonin metabolism is dysregulated in cholangiocarcinoma, which has implications for tumor growth.

Cholangiocarcinoma is a devastating cancer of biliary origin with limited treatment options. Symptoms are usually evident after blockage of the bile duct by the tumor, and at this late stage, they are relatively resistant to chemotherapy and radiation therapy. Therefore, it is imperative that alternative treatment options are explored. We present novel data indicating that the metabolism of serotonin is dysregulated in cholangiocarcinoma cell lines, compared with normal cholangiocytes, and tissue and bile from cholangiocarcinoma patients. Specifically, there was an increased expression of tryptophan hydroxylase 1 and a suppression of monoamine oxidase A expression (enzymes responsible for the synthesis and degradation of serotonin, respectively) in cholangiocarcinoma. This resulted in an increased secretion of serotonin from cholangiocarcinoma and increased serotonin in the bile from cholangiocarcinoma patients. Increased local serotonin release may have implications on cholangiocarcinoma cell growth. Serotonin administration increased cholangiocarcinoma cell growth in vitro, whereas inhibition of serotonin synthesis decreases tumor cell growth both in vitro and in vivo. The data presented here represent the first evidence that serotonin metabolism is dysregulated in cholangiocarcinoma and that modulation of serotonin synthesis may represent an alternative target for the development of therapeutic strategies.

Oxysterols induce cyclooxygenase-2 expression in cholangiocytes: implications for biliary tract carcinogenesis.

Cyclooxygenase‐2 (COX‐2), which is expressed by cholangiocytes in biliary tract disorders, has recently been implicated in biliary tract carcinogenesis. The mechanisms responsible for this COX‐2 expression remain unclear. In human diseases, bile contains oxygenated derivatives of cholesterol (oxysterols) which possess diverse biological properties. Therefore, we determined if oxysterols modulate COX‐2 expression. The effect of an oxysterol (22(R)‐hydroxycholesterol, 22‐HC) on COX‐2 expression in KMBC cells, a human cholangiocarcinoma cell line, was examined. 22‐HC enhanced COX‐2 protein expression. This oxysterol activated p42/44 and p38 MAPK, but not JNK 1/2. A p42/44 MAPK inhibitor did not block COX‐2 induction, while p38 MAPK inhibitor effectively attenuated COX‐2 induction. Although COX‐2 mRNA levels were increased by 22‐HC, this increase was not transcriptionally regulated, as 22‐OH did not increase activity in a COX‐2 promoter gene assay. In contrast, COX‐2 mRNA stability was augmented by 22‐HC treatment, and this effect was reversed by a p38 MAPK inhibitor. In conclusion, the results demonstrate that the oxysterol 22‐HC stabilizes COX‐2 mRNA via a p38 MAPK‐dependent mechanism. This enhanced COX‐2 protein expression by oxysterols may participate in the genesis and progression of cholangiocarcinoma. (HEPATOLOGY 2004;39:732–738.)

Model Bile and Bile Salts Accelerate Mucin Secretion by Cultured Dog Gallbladder Epithelial Cells

BACKGROUND & AIMS Hypersecretion of gallbladder mucin has been proposed as a pathogenic factor in gallstone formation. We investigated whether mucin secretion is modulated by biliary constituents using normal, well-differentiated dog gallbladder epithelial cells. METHODS Model biles or bile salts were applied to monolayers of epithelial cells. Mucin secretion was studied by measuring the secretion of [3H]N-acetyl-D-glucosamine-labeled glycoproteins. RESULTS Model biles with different cholesterol saturation indices increased mucin secretion by the cells to an average 251% after 5 hours of incubation (P < 0.01). Mucin secretion remained elevated during a 24-hour period, suggesting a sustained effect on mucin secretion. There was no relation between the cholesterol or phospholipid concentration and the extent of stimulation of mucin secretion. Taurocholate caused a dose-dependent increase in mucin secretion, suggesting that bile salt was the bile component responsible for the stimulatory effect. At a concentration of 0.5 mmol/L, only the more hydrophobic bile salts taurochenodeoxycholate and taurodeoxycholate, but not the hydrophylic bile salts taurocholate and tauroursodeoxycholate, stimulated mucin secretion (P < 0.01). CONCLUSIONS Bile salts play an important role in the regulation of mucin secretion. A shift in the bile salt composition of bile towards the more hydrophobic bile salts may cause mucin hypersecretion, thereby initiating cholesterol gallstone formation.