Background: Biliary lipids and nucleation time are increasingly of importance in the understanding of the cholesterol nucleation process in gallstone patients.
Methods: Biliary lipids, total lipid concentration (TLC), cholesterol saturation index (CSI) and nucleation time (NT) were studied in 221 bile samples from patients with solitary (n = 120) and multiple (n = 101) gallbladder stones.
Results: Biliary cholesterol concentration and CSI did not differ between patients with solitary or multiple stones; however, it was positively correlated with the CSI (r = 0.93; p < 0.01). We found a negative correlation between CSI and TLC (r = -0.77 for solitary stones and r = -0.79 for multiple stones; p < 0.01). Furthermore, levels of total bile acids and phospholipids were similar in cases with solitary and multiple gallbladder stones. TLC did not correlate with single or multiple stones, whereas NT was determined to be negatively correlated with the number of gallstones (r = -0.39; p < 0.01). Patients with solitary stones had a significantly (p < 0.01) longer NT than those with multiple gallbladder stones (7.5 +/- 4.2 days versus 2.3 +/- 1.5 days).
Conclusions: Our findings suggest that there exists a nucleation-promoting activity, which seems to be more pronounced in patients with multiple gallbladder stones than in those with solitary stones, indicating a major risk factor for the higher recurrence rate seen in these patients.