Measurement of cholesterol gallstone growth in vitro

In vitro analysis of gallstone formation in the presence of bacteria

AIM

In our previous study, we have isolated different genera of bacteria from gallstones and this intrigued us to study their role in gallstone formation. The isolates exhibited certain biliary activities like urease activity, slime production, and β-glucuronidase production. We aimed to investigate the role of these factors in the formation of gallstone in in vitro conditions at a supersaturated concentration of cholesterol.

METHODOLOGY

To mimic bile in in vitro state, Brilliant Green Bile Broth (BGBB) media having a composition similar to human bile was used. Four different experimental sets were prepared, each having nine flasks with varying concentrations of cholesterol and CaCO3 (calcium carbonate). Test sets I, II, III, and IV were inoculated with Salmonella, Enterococcus, Helicobacter, and Neisseria respectively, which were isolated from gallstone itself. Out of these four bacteria, only Helicobacter did not possess slime activity. A control set was also established which was devoid of bacteria. The control also had nine flasks with different concentrations of cholesterol and CaCO3. All the sets were incubated in the incubator shaker at 37 °C and 80 revolution per minutes (RPM) for 20 days.

RESULT

It was observed that the sets having bacteria had a less nucleation time as compared to the control (F = 5.274; p < 0.001). Solidification of gallstone was observed only in the set with bacteria having slime activity (sets I, II, and IV).

CONCLUSION

The slime activity of bacteria leads to solidification of gallstones, whereas the other activities accelerate the nucleation of gallstone formation enhancing the severity of the disease.

The physical presence of gallstone modulates ex vivo cholesterol crystallization pathways of human bile

BACKGROUND

Cholesterol crystallization is an essential step toward gallstone formation. Although model bile studies showed that competition occurs between the gallstone surface and the surrounding aqueous phase for cholesterol molecules available for crystallization, this has not been investigated in human bile.

METHODS

Fresh gallbladder bile was obtained during laparoscopic cholecystectomy from 13 patients with cholesterol (n = 10) or pigment (n = 3) stones. Small cholesterol gallstones were collected from another two patients. Both native and ultrafiltered bile with or without added gallstones was analysed by polarized light microscopy for the presence of arc-like and needle-like anhydrous cholesterol crystals and classic cholesterol monohydrate crystals. Weight of the added stones was evaluated before and after 21 days of bile incubation.

RESULTS

In unfiltered bile, the presence of stones was associated with a trend towards less anhydrous cholesterol crystals, but significantly more aggregated cholesterol monohydrate crystals. In ultrafiltered bile, the presence of stones tended to inhibit the formation of arc-like or needle-like crystals and was associated with significantly greater amounts of both plate-like and aggregated cholesterol monohydrate crystals. After 21 days of the incubation, stone weight was decreased in both unfiltered (-4.5 ± 1.6%, P = 0.046) and ultrafiltered bile (-6.5 ± 1.5%, P = 0.002). Bile from pigment-stone patients was clear in the absence of stones, but showed early appearance of plate-like and aggregated cholesterol monohydrate crystals in all samples to which cholesterol gallstones were added.

CONCLUSIONS

The physical presence of cholesterol gallstones in both native and filtered bile greatly influences cholesterol crystallization pathways. Whereas cholesterol monohydrate crystals increase, anhydrous cholesterol crystals tend to be inhibited. Detachment of solid cholesterol crystals from the gallstone surface may explain these findings.

Is biliary microlithiasis a significant cause of idiopathic recurrent acute pancreatitis? A long-term follow-up study

BACKGROUND & AIMS

The cause of recurrent acute pancreatitis (RAP) is not known in 10%-30% of patients. The aim of the present study was to determine the cause of idiopathic RAP in a long-term follow-up study.

METHODS

All consecutive patients with idiopathic RAP underwent detailed evaluations and investigations to find out the cause. The pancreatitis was considered to be idiopathic when no cause could be found after standard investigations that included serum biochemistry, transabdominal ultrasonography, and computerized tomography scan of the abdomen. The detailed work-up included repeat serum biochemistry and transabdominal ultrasonography, an endoscopic retrograde cholangiopancreatography, duodenal bile microscopy to diagnose biliary microlithiasis, and endoscopic ultrasonography.

RESULTS

Seventy-five patients were studied from June 1995 to May 2003. Their mean age was 31.9 years and 80% were male. The mean number of attacks of acute pancreatitis was 4.82 (range, 2-10). The cause of RAP was attributed to biliary microlithiasis in only 10 (13%) of 75 patients. Two additional patients developed gallstones during the follow-up period. Thirty-five (47%) patients developed chronic pancreatitis during the follow-up period. Ten of these 35 patients with chronic pancreatitis had biliary microlithiasis; 8 of these 10 patients had undergone cholecystectomy/endoscopic sphincterotomy yet continued to have recurrent pancreatitis and developed chronic pancreatitis. Miscellaneous causes were found in 10 (13%) patients. No cause was found in the remaining 18 (24%) patients.

CONCLUSIONS

Microlithiasis was not a significant cause of idiopathic RAP in our patients. About one half of the patients with RAP developed chronic pancreatitis during the follow-up period.

Gallstone disease: Primary and secondary prevention

Several risk factors for cholesterol gallstone formation in the general population have been identified. There is a strongly increased risk of gallstone disease during prolonged fasting, rapid weight loss, total parenteral nutrition, and somatostatin(-analogue) treatment. The annual risk of biliary colic and gallstone complications in asymptomatic gallstone carriers has been investigated sparsely. In asymptomatic and symptomatic gallstone carriers, treatment with the hydrophilic bile salt ursodeoxycholic acid (UDCA) has been claimed to reduce the risk of biliary colic and gallstone complications such as acute cholecystitis and acute pancreatitis. Also, prophylactic cholecystectomy could be beneficial in certain subgroups of asymptomatic gallstone carriers. However, randomized, double-blind, placebo-controlled trials are lacking. In this review, strategies for the prevention of gallstone formation in the general population and in high-risk conditions are dealt with. Also, strategies for the prevention of biliary colic and gallstone complications in asymptomatic and symptomatic gallstone carriers are discussed.

Small gallstones are associated with increased risk of acute pancreatitis: potential benefits of prophylactic cholecystectomy?

OBJECTIVES

Pancreatitis is a severe complication of gallstone disease with considerable mortality. Small gallstones may increase the risk of pancreatitis. Our aims were to evaluate potential association of small stones with pancreatitis and potential beneficial effects of prophylactic cholecystectomy.

METHODS

Stone characteristics were determined in patients with biliary pancreatitis (115), obstructive jaundice due to gallstones (103), acute cholecystitis (79), or uncomplicated gallstone disease (231). Sizes and numbers of gallbladder and bile duct stones were determined by ultrasonography and endoscopic retrograde cholangiopancreatography, respectively. Effects of prophylactic cholecystectomy were assessed by decision analyses with a Markov model and Monte Carlo simulations.

RESULTS

Patients with pancreatitis or obstructive jaundice had more and smaller gallbladder stones than those with acute cholecystitis or uncomplicated disease (diameters of smallest stones: 3 +/- 1, 4 +/- 1, 8 +/- 1, and 9 +/- 1 mm, respectively, p < 0.01). Bile duct stones were smaller in case of pancreatitis than in obstructive jaundice (diameters of smallest stones: 4 +/- 1 vs 8 +/- 1, p < 0.01). Multivariate analysis identified old age and small stones as independent risk factors for pancreatitis. Decision analysis in a representative group of patients with small (<or=5 mm) gallstones (5,000 patients, 67% females, 45 yr old, 10-yr follow-up) indicates that life-years may be gained or lost by cholecystectomy, depending on incidence and mortality of pancreatitis.

CONCLUSIONS

Small gallstones are associated with pancreatitis. Prophylactic cholecystectomy may lead to gain or loss of life-years in patients with small stones, depending on incidence and mortality of pancreatitis.

Small gallstones, preserved gallbladder motility, and fast crystallization are associated with pancreatitis

Acute pancreatitis is a severe complication of gallstones with considerable mortality. We sought to explore the potential risk factors for biliary pancreatitis. We compared postprandial gallbladder motility (via ultrasonography) and, after subsequent cholecystectomy, numbers, sizes, and types of gallstones; gallbladder bile composition; and cholesterol crystallization in 21 gallstone patients with previous pancreatitis and 30 patients with uncomplicated symptomatic gallstones. Gallbladder motility was stronger in pancreatitis patients than in patients with uncomplicated symptomatic gallstones (minimum postprandial gallbladder volumes: 5.8 +/- 1.0 vs. 8.1 +/- 0.7 mL; P = .005). Pancreatitis patients had more often sludge (41% vs. 13%; P = .03) and smaller and more gallstones than patients with symptomatic gallstones (smallest stone diameters: 2 +/- 1 vs. 8 +/- 2 mm; P = .001). Also, crystallization occurred much faster in the bile of pancreatitis patients (1.0 +/- 0.0 vs. 2.5 +/- 0.4 days; P < .001), possibly because of higher mucin concentrations (3.3 +/- 1.9 vs. 0.8 +/- 0.2 mg/mL; P = .04). No significant differences were found in types of gallstones, relative biliary lipid contents, cholesterol saturation indexes, bile salt species composition, phospholipid classes, total protein or immunoglobulin (G, M, and A), haptoglobin, and alpha-1 acid glycoprotein concentrations. In conclusion, patients with small gallbladder stones and/or preserved gallbladder motility are at increased risk of pancreatitis. The potential benefit of prophylactic cholecystectomy in this patient category has yet to be explored.