An estimation of human bile metastability: clinical application of a sensitive cholesterol crystal growth assay

The formation of cholesterol monohydrate crystal initiates cholesterol gallstone formation. The nucleation time (NT), a light microscopy method, is used currently to estimate human bile metastability. Recently, a cholesterol crystal growth (CCG) assay utilizing photometric turbidity to quantitate cholesterol crystallization was developed using model bile systems. The object of this study was to determine whether this novel CCG assay was applicable to the quantitative assessment of native human bile metastability. Human gall-bladder bile samples were collected from patients undergoing cholecystectomy. There were five patients with cholesterol gallstone and five stone-free patients. A significant correlation between the onset time measured by the CCG assay and the NT observed by light microscopy was found in our modified assay condition where interference by bilirubin was negligible (P < 0.01). Also, the growth rate measured by the CCG assay significantly correlated with the NT (P < 0.05). These results indicate that the CCG assay is applicable to quantitative assessment of human bile metastability reflected by cholesterol crystal nucleation and that the cholesterol crystal growth is also conveniently estimated by this method.