Cholesterol trafficking-related serum lipoprotein functions in children with cholesteryl ester storage disease Francesca Zimetti a, 1 , Elda Favari a, *, 1 , Paola Cagliero b , Maria Pia Adorni a , Nicoletta Ronda a , Renato Bonardi c , Monica Gomaraschi d , Laura Calabresi d , Franco Bernini a , Ornella Guardamagna b a Department of Pharmacy, University of Parma, Parma, Italy b Department of Health Science and Pediatrics, University of Torino, Torino, Italy c Department of Medical Sciences, University of Torino, Torino, Italy d Centro E. Grossi Paoletti, Dipartimento di Scienze Farmacologiche e Biomolecolari, Universit a degli Studi di Milano, Milano, Italy article info Article history: Received 2 April 2015 Received in revised form 6 July 2015 Accepted 6 August 2015 Available online 10 August 2015 Keywords: HDL Atherosclerosis Cholesteryl ester storage disease Lipoproteins Lysosomal acid lipase Cholesterol efflux capacity Cholesterol loading capacity abstract Objective: Serum lipoproteins influence cell cholesterol content by delivering and removing cholesterol to/from cells, functions mainly exerted by LDL and HDL, respectively. Especially in the case of HDL, structure and composition are crucial for function, beyond serum levels. Cholesteryl ester storage disease (CESD) is caused by LIPA gene mutations and reduced activity of lysosomal acid lipase (LAL), the enzyme responsible for hydrolysis of cholesteryl esters and TG. CESD patients typically present dyslipidaemia, liver damage and premature atherosclerosis. The objective of this work was to evaluate serum HDL cholesterol efflux capacity (CEC) and serum cholesterol loading capacity (CLC) in CESD pediatric patients and to study lipoprotein qualitative modifications. Methods: HDL CEC was evaluated by radioisotopic techniques, serum CLC was measured by a fluorimetric assay, HDL subclasses were determined by two-dimensional electrophoresis. Results: CESD patients (n ¼ 3) displayed on average increased LDL cholesterol (þ163%; p ¼ 0.019), TG (þ203; p ¼ 0.012), phospholipids (þ40%; p ¼ 0.024) and lower HDL cholesterol (À57%; p ¼ 0.012) compared to controls (n ¼ 9). CESD HDL CEC was impaired both as a whole (average reduction of 26%; p < 0.0001) and with respect to specific membrane cholesterol transporters (À23% for aqueous diffusion; p ¼ 0.005; À32% for ABCA1-efflux; p ¼ 0.0002; À60% for SR-BI-efflux; p < 0.0001; À42% for ABCG1- efflux p ¼ 0.0003). A marked reduction in the pre-b HDL concentration (À69%; p ¼ 0.012) was detec- ted. Finally, CESD serum CLC was significantly increased (þ21%; p ¼ 0.0007). Conclusion: These new data demonstrate that the pro-atherogenic modifications of serum include disturbances in lipoprotein functions involved in cell cholesterol homeostasis occurring from very early age in CESD patients. © 2015 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Both alterations of lipid/lipoprotein metabolism and inflam- matory events contribute to the formation of the atherosclerotic plaque, characterized by the accumulation of abnormal amounts of cholesterol and macrophages in the artery wall. Reverse cholesterol transport (RCT) may counteract the pathogenic events leading to the formation and development of atheroma, by promoting the HDL-mediated removal of cholesterol from the artery wall [1]. Mechanisms accounting for cell cholesterol efflux include aqueous diffusion (AD) processes, as well as active pathways mediated by the cholesterol transporters ATP-binding cassette A1 (ABCA1), ATP- binding cassette G1 (ABCG1) and Scavenger Receptor Class B Type I (SR-BI) [2]. The ability of HDL to promote cholesterol efflux from macro- phages is thought to be important for the atheroprotective function of HDL [3] and several lines of evidence suggest that the efflux process is sensitive to HDL structure and composition rather than HDL-cholesterol (HDL-C) plasma levels. For example, it has been shown that the serum capacity to promote cholesterol efflux via * Corresponding author. Department of Pharmacy, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy. E-mail address: elda.favari@unipr.it (E. Favari). 1 These authors equally contributed to this study. Contents lists available at ScienceDirect Atherosclerosis journal homepage: www.elsevier.com/locate/atherosclerosis http://dx.doi.org/10.1016/j.atherosclerosis.2015.08.007 0021-9150/© 2015 Elsevier Ireland Ltd. All rights reserved. Atherosclerosis 242 (2015) 443e449