Emerging roles for phospholipid transfer protein in lipid and lipoprotein metabolism

Purpose of review This review highlights the recent key advances in our understanding of the role of phospholipid transfer protein in lipid and lipoprotein metabolism. Recent findings The overexpression of human phospholipid transfer protein in mice is associated with an increase in atherosclerosis. This is consistent with earlier studies using mouse models suggesting that phospholipid transfer protein was pro-atherogenic. The presence of phospholipid transfer protein in macrophages and atherosclerotic lesions suggests that it could be either anti-atherogenic by facilitating lipid efflux or pro-atherogenic by facilitating lipid retention. Phospholipid transfer protein may also be a key player in reverse cholesterol transport, as it interacts with the adenosine triphosphate-binding cassette transporter A1 and facilitates lipid efflux from peripheral cells. Both the release of chymase, a neutral protease, from mast cells and the oxidation of HDL by hypochlorous acid can impair the function of phospholipid transfer protein in reverse cholesterol transport. Studies of phospholipid transfer protein-mediated phospholipid transfer activity in humans support a role for phospholipid transfer protein in hypertriglyceridemia, obesity, diabetes, inflammation and coronary artery disease, and in the modulation of LDL particle density and size. Furthermore, recent evidence suggests that phospholipid transfer protein may play a role in reproductive processes, in lipid and lipoprotein metabolism in the central nervous system, and in neurodegenerative disease. Summary Phospholipid transfer protein is emerging as a multifaceted and multifunctional player in lipid and lipoprotein metabolism, but much additional work will be required to understand the significance of these recent findings for clinical practice.