Relationship between plasma phospholipid transfer protein activity and HDLsubclasses among patients with low HDL and cardiovascular disease

Low levels of high density lipoproteins (HDL) are associated with an increa sed risk for premature cardiovascular disease. The plasma phospholipid tran sfer protein (PLTP) is believed to play a critical role in lipoprotein meta bolism and reverse cholesterol transport by remodeling HDL and facilitating the transport of lipid to the liver. Plasma contains two major HDL subclas ses, those containing both apolipoproteins (apo) A-I and A-II, Lp(A-I, A-II ), and those containing apo A-I but not A-II, Lp(A-I). To examine the poten tial relationships between PLTP and lipoproteins, plasma PLTP activity, lip oprotein lipids, HDL subclasses and plasma apolipoproteins were measured in 52 patients with documented cardiovascular disease and low HDL levels. Amo ng the patients, plasma PLTP activity was highly correlated with the percen tage of plasma apo A-I in Lp(A-I) (r = 0.514, p < 0.001) and with the apo A -I, phospholipid and cholesterol concentration of Lp(A-I) (r = 0.499, 0.478 , 0.457, respectively, p less than or equal to 0.001). Plasma PLTP activity was also significantly correlated with plasma apo A-I (r = 0.413, p = 0.00 2), HDL cholesterol (r = 0.308, p = 0.026), and HDL, and HDL, cholesterol ( r = 0.284 and 0.276, respectively, p < 0.05), but no significant correlatio n was observed with Lp(A-I, A-II), plasma cholesterol, triglycerides, or ap o B, very low density lipoprotein cholesterol or low density lipoprotein ch olesterol. These associations support the hypothesis that PLTP modulates pl asma levels of Lp(A-I) particles without significantly affecting the levels of Lp(A-I, A-II) particles. (C) 1999 Elsevier Science Ireland Ltd. Al righ ts reserved.