Organochloride pesticides induced hepatic ABCG5/G8 expression and lipogenesis in Chinese patients with gallstone disease

Background: Organochlorine pesticides (OCPs) are one kind of persistent organic pollutants. Although they are reported to be associated with metabolic disorders, the underlying mechanism is unclear. We explored the association of OCPs with gallstone disease and its influence on hepatic lipid metabolism. Materials and Methods: OCPs levels in omentum adipose tissues from patients with and without gallstone disease between 2008 and 2011 were measured by GC-MS. Differences of gene expression involved in hepatic lipid metabolism and hepatic lipids content were compared in liver biopsies between groups with high and low level of OCPs. Using HepG2 cell lines, the influence on hepatic lipid metabolism by individual OCP was evaluated in vitro. Results: In all patients who were from non-occupational population, there were high levels of beta-hexachlorocyclohexane (beta-HCH) and p', p'-dichloroethylene (p', p'-DDE) accumulated in adipose tissues. Both beta-HCH and p', p'-DDE levels were significantly higher in adipose tissues from patients with gallstone disease (294.3 +/- 313.5 and 2222 +/- 2279 ng/g of lipid) than gallstone-free controls (282.7 +/- 449.0 and 2025 +/- 2664 ng/g of lipid, P<0.01) and they were strongly related with gallstone disease (P for trend = 0.0004 and 0.0138). Furthermore, higher OCPs in adipose tissue led to increase in the expression of hepatic cholesterol transporters ABCG5 and G8 (+ 34% and + 27%, P<0.01) and higher cholesterol saturation index in gallbladder bile, and induced hepatic fatty acids synthesis, which was further confirmed in HepG2 cells. Conclusion: OCPs might enhance hepatic secretion of cholesterol into bile via ABCG5/G8 which promoting gallstone disease as well as lipogenesis.