The role of plasma phospholipid transfer protein (PLTP) in HDL remodeling in acute-phase patients

During reverse cholesterol transport plasma phospholipid transfer protein ( PLTP) converts high density lipoprotein., (HDL3) into two new subpopulation s, HDL2-like particles and pre-beta -HDL. The acute-phase response is accom panied with dramatic changes in lipid metabolism including alterations in H DL concentration, composition, and thereby its function as a substrate for HDL remodeling proteins in circulation. To evaluate how acute-phase HDL (AP -HDL) functions in PLTP-mediated HDL conversion, we collected plasma sample s from patients with severe acute-phase response (n = 17), and from healthy controls (n = 30). Subsequently, total HDL (1.063 < d < 1.21 g/ml) was iso lated from patients and controls and incubated in the absence and presence of purified PLTP. The results show that HDL isolated from the acute-phase p atients is converted by PLTP in vitro in a corresponding manner as normal H DL. In the combined population, C-reactive protein correlated significantly with lecithin-cholesterol acyltransferase (LCAT) activity (r = -0.53), cho lesterol ester transfer protein activity (r = -0.80), PLTP activity (r = 0. 44), and PLTP mass (r = -0.66). When compared to the controls, the patients had 31% higher PLTP activity, but 52% lower PLTP mass leading to a 165% hi gher PLTP specific activity in the patients. The present data indicate that during the acute-phase response, plasma PUP activity and mass are strongly affected by the lipoprotein distribution as well as lipid composition. We suggest that the decrease of HDL during the acute phase is caused by reduce d LCAT and increased PLTP activities both increasing the plasma levels of l ipid-poor apoA-I particles. (C) 2001 Elsevier Science B.V. All rights reser ved.