A proteomic approach to identify novel disease biomarkers in LCAT deficiency

Genetic LCAT deficiency is a rare recessive autosomal disease due to loss-of-function mutations in the gene coding for the enzyme lecithin:cholesterol acyltransferase (LCAT). Homozygous carriers are characterized by corneal opacity, haemolytic anaemia and renal disease, which represent the first cause of morbidity and mortality in these subjects. Diagnostic and prognostic markers capable of early detecting declining kidney function in these subjects are not available, and the specific serum or urine proteomic signature of LCAT deficient carriers has never been assessed. Taking advantage of a proteomic approach, we performed 2-DE analysis of carriers' plasma and identified proteins present at different concentration in samples from homozygous carriers. Our data confirm the well-known alterations in the concentration of circulating apolipoproteins, with a statistically significant decrease of both apoA-I and apoA-II and a statistically significant increase of apoC-III. Furthermore, we observed increased level of alpha-1-antitrypsin, zinc-alpha-2-glycoprotein and retinol-binding protein 4, and reduced level of clusterin and haptoglobin. Interestingly, only beta but not alpha subunit of haptoglobin is significant reduced in homozygous subjects. Despite the limited sample size, our findings set the basis for assessing the identified protein in a larger population and for correlating their levels with clinical markers of renal function and anaemia. Significance: This investigation defines the effects of LCAT deficiency on the level of the major plasma proteins in homozygous and heterozygous carriers. Increase for some proteins, with different function, together with a drop for haptoglobin, and specifically for haptoglobin beta chains, are reported for the first time as part of a coherent signature. We are glad to have the opportunity to report our findings on this subject, which is one of the main interests for our research group, when Journal of Proteomics celebrates its 10th anniversary. With its various sections devoted to different areas of research, this journal is a privileged forum for publishing proteomic investigations without restrictions either in sample type or in technical approach. It is as well a privileged forum for reviewing literature data on various topics related to proteomics investigation, as colleagues in our research group have done over the years; by the way, a good share of the reviewed papers were as well reports published in Journal of Proteomics itself. The journal also offers opportunities for focused surveys through thematic issues devoted to a variety of subjects, timely selected for their current relevance in research; it was an honour for colleagues in our group to recently act as editors of one of those. Out of this diverse experience, we express our appreciation for the endeavour of Journal of Proteomics in its first 10 years of life \u2013 and wish identical and possibly greater success for the time to come

Analysis of HDL-microRNA panel in heterozygous familial hypercholesterolemia subjects with LDL receptor null or defective mutation

In the last years increasing attention has been given to the connection between genotype/phenotype and cardiovascular events in subjects with familial hypercholesterolemia (FH). MicroRNAs (miRs) bound to high-density lipoprotein (HDL) may contribute to better discriminate the cardiovascular risk of FH subjects. Our aim was to evaluate the HDL-miR panel in heterozygous FH (HeFH) patients with an LDLR null or defective mutation and its association with pulse wave velocity (PWV). We evaluated lipid panel, HDL-miR panel and PWV in 32 LDLR null mutation (LDLR-null group) and 35 LDLR defective variant (LDLR-defective group) HeFH patients. HDL-miR-486 and HDL-miR-92a levels were more expressed in the LDLR-null group than the LDLR-defective group. When we further stratified the study population into three groups according to both the LDLR genotype and history of ASCVD (LDLR-null/not-ASCVD, LDLR-defective/not-ASCVD and LDLR/ASCVD groups), both the LDLR/ASCVD and the LDLR-null/not-ASCVD groups had a higher expression of HDL-miR-486 and HDL-miR-92a than the LDLR-defective/not-ASCVD group. Finally, HDL-miR-486 and HDL-miR-92a were independently associated with PWV. In conclusion, the LDLR-null group exhibited HDL-miR-486 and HDL-miR-92a levels more expressed than the LDLR-defective group. Further studies are needed to evaluate these HDL-miRs as predictive biomarkers of cardiovascular events in FH

Il trattamento con topiramato protegge i topi APOE-KO dall’insorgenza di danno renale senza modificare i livelli dei lipidi plasmatici

Il topiramato e\u300 un farmaco impiegato nel trattamento dell\u2019epilessia e prescritto anche nella profilassi dell\u2019emicrania che si caratterizza per i molteplici meccanismi d\u2019azione. Diversi studi indicano che il trattamento con topiramato promuove la riduzione del peso corporeo e riduce moderatamente i livelli dei lipidi plasmatici e la glicemia. In considerazione di questi effetti metabolici positivi si e\u300 deciso di valutare se il trattamento con topiramato potesse modulare lo sviluppo di aterosclerosi e al tempo stesso avere effetti protettivi sugli organi bersaglio di condizioni dismetaboliche. Trenta topi apoE-KO sono stati distribuiti in tre gruppi sperimentali e alimentati per 12 settimane con una dieta ad elevato contenuto lipidico (controllo), oppure con la stessa dieta addizionata con topiramato allo 0.125% o allo 0.25%. Il peso corporeo e il consumo di cibo e acqua sono stati monitorati durante tutto lo studio. E\u300 stata inoltre misurata la concentrazione dei lipidi plasmatici e la glicemia, ed e\u300 stato effettuato un test di tolleranza al glucosio. Lo sviluppo di aterosclerosi e\u300 stato valutato nell\u2019intera aorta e nel seno aortico. Sono state inoltre condotte indagini istologiche su fegato, rene e tessuto adiposo. Il trattamento con topiramato non ha influenzato l\u2019aumento di peso corporeo o il consumo di cibo. La tolleranza al glucosio e la concentrazione lipidica plasmatica sono risultati comparabili tra i gruppi, cosi\u300 come lo sviluppo di aterosclerosi. Il trattamento non ha inoltre alterato l\u2019istologia del fegato e del tessuto adiposo. A livello renale, il trattamento con topiramato ha invece ridotto l\u2019insorgenza di lipidosi glomerulare in modo dose-dipendente, riducendo l\u2019accumulo di cellule schiumose e l\u2019espressione di marcatori di infiammazione. Inoltre, anche i livelli plasmatici di urea sono risultati ridotti in seguito al trattamento. In conclusione, i risultati ottenuti indicano che il trattamento con topiramato non influenza lo sviluppo di aterosclerosi, ma preserva struttura e funzionalita\u300 renale. Il topiramato potrebbe pertanto essere preso in considerazione in studi di riposizionamento farmacologico per il trattamento della lipidosi glomerulare

The effect of phospholipid composition of reconstituted HDL on its cholesterol efflux and anti-inflammatory properties

goal of this study was to understand how the reconstituted HDL (rHDL) phospholipid (PL) composition affects its cholesterol efflux and anti-inflammatory properties. An ApoA-I mimetic peptide, 5A, was combined with either SM or POPC. Both lipid formulations exhibited similar in vitro cholesterol efflux by ABCA1, but 5A-SM exhibited higher ABCG1- and SR-BI-mediated efflux relative to 5A-POPC (P < 0.05). Injection of both rHDLs in rats resulted in mobilization of plasma cholesterol, although the relative potency was 3-fold higher for the same doses of 5A-SM than for 5A-POPC. Formation of pre HDL was observed following incubation of rHDLs with both human and rat plasma in vitro, with 5A-SM inducing a higher extent of pre formation relative to 5A-POPC. Both rHDLs exhibited anti-inflammatory properties, but 5A-SM showed higher inhibition of TNF-, IL-6, and IL-1 release than did 5A-POPC (P < 0.05). Both 5A-SM and 5A-POPC showed reduction in total plaque area in ApoE(-/-) mice, but only 5A-SM showed a statistically significant reduction over placebo control and baseline (P < 0.01). The type of PL used to reconstitute peptide has significant influence on rHDL's anti-inflammatory and anti-atherosclerosis properties

Complete and Partial LCAT Deficiency are Differentially Associated with Atherosclerosis

Background\u2014Lecithin:cholesterol acyltransferase (LCAT) is the sole enzyme that esterifies cholesterol in plasma. Its role in the supposed protection from atherogenesis remains unclear since mutations in LCAT causing Fish-Eye Disease (FED) or Familial LCAT Deficiency (FLD) have been reported to be associated with more or instead less carotid atherosclerosis, respectively. This discrepancy may be associated with the loss of cholesterol esterification on only apolipoprotein (apo) A-I (FED) or on both apoA-I and apoB-containing lipoproteins (FLD), an aspect that has thus far not been investigated. Methods\u2014Seventy-four heterozygotes for LCAT mutations recruited from Italy and the Netherlands were assigned to FLD (n=33) or FED (n=41) groups and compared to 280 controls. Subclinical atherosclerosis was assessed using carotid intima-media thickness (IMT). Results\u2014Compared to controls, total cholesterol was lower by 16% (-32.9 mg/dL) and 7% (-14.9 mg/dL), and HDL cholesterol was lower by 29% (-16.7 mg/dL) and 36% (-20.7 mg/dL) in the FLD and FED groups, respectively. FLD subjects displayed a significant 18% lower LDL cholesterol compared with FED (101.9\ub135.0 vs 123.6\ub147.4 mg/dL, P=0.047) and controls (122.6\ub135.0 mg/dL, P=0.003). Remarkably, all three IMT parameters were lower in FLD compared to FED and controls (accounting for age, sex, BMI, smoking, hypertension, family history of cardiovascular disease and plasma lipids). After additional correction for nationality and ultrasonographic methods, average and maximum IMT remained significantly lower when comparing FLD to FED (0.59mm vs 0.73mm, P=0.003, and 0.87mm vs 1.24mm, P&lt;0.001, respectively). By contrast, the common carotid IMT (corrected for age, sex, BMI, smoking, hypertension, family history of cardiovascular disease, and plasma lipids) was higher in FED compared to controls (0.69mm versus 0.65mm, P=0.05), but this significance was lost after adjustment for nationality and ultrasonographic machine. Conclusions\u2014In this head-to-head comparison, FLD and FED mutations were shown to be associated with decreased and increased atherosclerosis, respectively. We propose that this discrepancy is related to the capacity of LCAT to generate cholesterol esters on apoB-containing lipoproteins. While this capacity is lost in FLD, it is unaffected in FED. These results are important when considering LCAT as a target to decrease atherosclerosis

Ambulatory blood pressure in untreated and treated hypertensive patients at high altitude: the high altitude cardiovascular research-andes study

Blood pressure increases during acute exposure to high altitude in healthy humans. However, little is known on altitude effects in hypertensive subjects or on the treatment efficacy in this condition. Objectives of High Altitude Cardiovascular Research (HIGHCARE)-Andes Lowlanders Study were to investigate the effects of acute high-altitude exposure on 24-hour ambulatory blood pressure in hypertensive subjects and to assess antihypertensive treatment efficacy in this setting. One hundred untreated subjects with mild hypertension (screening blood pressure, 144.1\ub19.8 mm Hg systolic, 92.0\ub17.5 mm Hg diastolic) were randomized to double-blind placebo or to telmisartan 80 mg+modified release nifedipine 30 mg combination. Twenty-four-hour ambulatory blood pressure monitoring was performed off-treatment, after 6 weeks of treatment at sea level, on treatment during acute exposure to high altitude (3260 m) and immediately after return to sea level. Eighty-nine patients completed the study (age, 56.4\ub117.6 years; 52 men/37 women; body mass index, 28.2\ub13.5 kg/m 2). Twenty-four-hour systolic blood pressure increased at high altitude in both groups (placebo, 11.0\ub19 mm Hg; P<0.001 and active treatment, 8.1\ub110.4 mm Hg; P<0.001). Active treatment reduced 24-hour systolic blood pressure both at sea level and at high altitude (147.9\ub111.1 versus 132.6\ub112.4 mm Hg for placebo versus treated; P<0.001; 95% confidence interval of the difference 10.9-19.9 mm Hg) and was well tolerated. Similar results were obtained for diastolic, for daytime blood pressure, and for nighttime blood pressure. Treatment was well tolerated in all conditions. Our study demonstrates that (1) 24-hour blood pressure increases significantly during acute high-altitude exposure in hypertensive subjects and (2) treatment with angiotensin receptor blocker-calcium channel blocker combination is effective and safe in this condition

High-Density Lipoprotein, Lecithin: Cholesterol Acyltransferase, and Atherosclerosis

Epidemiological data clearly show the existence of a strong inverse correlation between plasma high-density lipoprotein cholesterol (HDL-C) concentrations and the incidence of coronary heart disease. This relation is explained by a number of atheroprotective properties of HDL, first of all the ability to promote macrophage cholesterol transport. HDL are highly heterogeneous and are continuously remodeled in plasma thanks to the action of a number of proteins and enzymes. Among them, lecithin:cholesterol acyltransferase (LCAT) plays a crucial role, being the only enzyme able to esterify cholesterol within lipoproteins. LCAT is synthetized by the liver and it has been thought to play a major role in reverse cholesterol transport and in atheroprotection. However, data from animal studies, as well as human studies, have shown contradictory results. Increased LCAT concentrations are associated with increased HDL-C levels but not necessarily with atheroprotection. On the other side, decreased LCAT concentration and activity are associated with decreased HDL-C levels but not with increased atherosclerosis. These contradictory results confirm that HDL-C levels per se do not represent the functionality of the HDL system

HDL and endothelial protection : examining evidence from HDL inherited disorders

Epidemiological studies have clearly demonstrated that plasma concentrations of HDL cholesterol are strongly and inversely associated with cardiovascular risk. Besides playing a major role in reverse cholesterol transport, the process by which excess cholesterol in the arterial wall is removed by HDL and delivered to the liver for excretion, HDL have other atheroprotective functions. In particular, HDL can contribute to the maintenance of endothelial cell homeostasis by inhibiting cell adhesion molecule expression, by promoting the release of bioactive molecules such as nitric oxide and prostacyclin, and by regulating cell proliferation and migration. HDL inherited disorders represent a unique tool to understand the relationship between HDL concentration, HDL function and HDL-mediated atheroprotection