Essential phospholipids decrease apoptosis and increase membrane transport in human hepatocyte cell lines.

ABSTRACT

BACKGROUND: Essential phospholipids (EPL) have hepatoprotective effects across many liver diseases/conditions. The impact of EPL on hepatocyte function in vitro was investigated. METHODS: Effects of noncytotoxic concentrations of EPL (0.1 and 0.25 mg/ml), and its constituents, polyenylphosphatidylcholine (PPC) and phosphatidylinositol (PI) (both at 0.1 and 1 mg/ml), on membrane fluidity, apoptosis and extracellular transport versus controls were investigated in human hepatocyte cell lines (HepG2, HepaRG, steatotic HepaRG).  RESULTS: Significantly increased membrane fluidity occurred with all 3 phospholipids (PLs) in HepG2 cultures, and with PI (1 mg/ml) in steatotic HepaRG cells. Significantly decreased tamoxifen-induced apoptosis was observed in HepG2 cells with EPL, PPC and PI. Breast cancer resistance protein (BCRP) activity was significantly increased by EPL and PI in HepG2 cells. Multidrug resistance-associated protein 2 (MRP-2) activity was unaffected by any PL in HepG2 cells, and significantly increased by EPL, PI and PPC (1 mg/ml) in HepaRG cells, and by PI (1 mg/ml) in steatotic HepaRG cells. Bile salt export protein (BSEP) activity in HepG2 cells and steatotic HepaRG cells was significantly increased by EPL (0.25 mg/ml), and PPC (both concentrations), but not by PI. The PLs had no effects on HepaRG cell BSEP activity. P-glycoprotein (P-GP) activity was significantly increased by all compounds in HepG2 cells. PI (1 mg/ml) significantly increased P-GP activity in HepaRG and steatotic HepaRG cells. CONCLUSIONS: EPL, PPC, and PI increased hepatocyte membrane fluidity, decreased apoptosis and increased hepatocellular export, all of which may improve liver function. These in-vitro investigations provide valuable insights into the mechanism of action of EPL.