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Calabresi L.,University of Milan | Baldassarre D.,University of Milan | Baldassarre D.,Monzino Cardiologic Institute | Simonelli S.,University of Milan | And 19 more authors.
Journal of Lipid Research | Year: 2011

Lecithin:cholesterol acyltransferase (LCAT) is the enzyme responsible for cholesterol esterification in plasma. LCAT is a major factor in HDL remodeling and metabolism, and it has long been believed to play a critical role in macrophage reverse cholesterol transport (RCT). The effect of LCAT on human atherogenesis is still controversial. In the present study, the plasma LCAT concentration was measured in all subjects (n = 540) not on drug treatment at the time of enrollment in the multicenter, longitudinal, observational IMPROVE study. Mean and maximum intimamedia thickness (IMT) of the whole carotid tree was measured by B-mode ultrasonography in all subjects. In the entire cohort, LCAT quartiles were not associated with carotid mean and maximum IMT ( P for trend 0.95 and 0.18, respectively), also after adjustment for age, gender, HDL-cholesterol (HDL-C), and triglycerides. No association between carotid IMT and LCAT quartiles was observed in men (P =0.30 and P=0.99 for mean and maximum IMT, respectively), whereas carotid IMT increased with LCAT quartiles in women ( P for trend 0.14 and 0.019 for mean and maximum IMT, respectively). The present findings support the concept that LCAT is not required for an efficient reverse cholesterol transport and that a low plasma LCAT concentration and activity is not associated with increased atherosclerosis. Copyright © 2011 by the American Society for Biochemistry and Molecular Biology, Inc.

Calabresi L.,University of Milan | Simonelli S.,University of Milan | Conca P.,University of Milan | Busnach G.,Niguarda Ca Granda Hospital | And 6 more authors.
Journal of Internal Medicine | Year: 2015

Objectives: It has been suggested that a low plasma high-density lipoprotein cholesterol (HDL-C) level contributes to the high cardiovascular disease risk of patients with chronic kidney disease (CKD), especially those undergoing haemodialysis (HD). The present study was conducted to gain further understanding of the mechanism(s) responsible for the low HDL-C levels in patients with CKD and to separate the impact of HD from that of the underlying CKD. Methods: Plasma lipids and lipoproteins, HDL subclasses and various cholesterol esterification parameters were measured in a total of 248 patients with CKD, 198 of whom were undergoing HD treatment and 40 healthy subjects. Results: Chronic kidney disease was found to be associated with highly significant reductions in plasma HDL-C, unesterified cholesterol, apolipoprotein (apo)A-I, apoA-II and LpA-I:A-II levels in both CKD cohorts (with and without HD treatment). The cholesterol esterification process was markedly impaired, as indicated by reductions in plasma lecithin:cholesterol acyltransferase (LCAT) concentration and activity and cholesterol esterification rate, and by an increase in the plasma preβ-HDL content. HD treatment was associated with a further lowering of HDL levels and impaired plasma cholesterol esterification. The plasma HDL-C level was highly significantly correlated with LCAT concentration (R = 0.438, P < 0.001), LCAT activity (R = 0.243, P < 0.001) and cholesterol esterification rate (R = 0.149, P = 0.031). Highly significant correlations were also found between plasma LCAT concentration and levels of apoA-I (R = 0.432, P < 0.001), apoA-II (R = 0.275, P < 0.001), LpA-I (R = 0.326, P < 0.001) and LpA-I:A-II (R = 0.346, P < 0.001). Conclusion: Acquired LCAT deficiency is a major cause of low plasma HDL levels in patients with CKD, thus LCAT is an attractive target for therapeutic intervention to reverse dyslipidaemia, and possibly lower the cardiovascular disease risk in these patients. © 2014 The Association for the Publication of the Journal of Internal Medicine.

Gomaraschi M.,University of Milan | Ossoli A.,University of Milan | Favari E.,University of Parma | Adorni M.P.,University of Parma | And 6 more authors.
Cardiovascular Research | Year: 2013

Aims: The aim of the present study was to evaluate the high-density lipoprotein (HDL) structure and endothelial NO synthase (eNOS) activation capacity in ST-elevation myocardial infarction (STEMI) patients with different acute-phase inflammatory response (APR). Methods and results: Forty-five STEMI patients were stratified in quartiles according to the delta CRP level, calculated by subtracting the CRP value atadmission from the CRP peak value (APR peak). The HDL structure and HDL capacity tostimulate NO production were evaluated at admission and at APRpeak. STEMI patients with a low APR had a completely preserved HDL structure and HDL ability to activate eNOS and promote NO production, which did not change during STEMI. On the contrary, HDL from STEMI patients developing a significant APR had compromised ability to stimulate eNOS and promote NO production, and underwent a significant particle remodelling during STEMI. The defective capacity to stimu-late NO production of HDL isolated from STEMI patients with high APR was explained, at least in part, by the reduced PON-1 and S1P content. The HDL ability to promote cell cholesterol efflux through different pathways was preserved in ACS patients independently of the inflammatory response. Conclusion: The present results extend previous studies reporting an impaired eNOS-activating capacity of HDL from ACS patients, showing that only a subset of patients undergoing STEMI, and in particular those developing an important inflammatory response, have circulating HDL defective in stimulating endothelial eNOS and NO production. © The Author 2013.

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