Identification of circulating apolipoprotein M as a new determinant of insulin sensitivity and relationship with adiponectin.

BACKGROUND: The adiponectin is one of the rare adipokines down-regulated with obesity and protects against obesity-related disorders. Similarly, the apolipoprotein M (apoM) is expressed in adipocytes and its expression in adipose tissue is associated with metabolic health. We compared circulating apoM with adiponectin regarding their relationship with metabolic parameters and insulin sensitivity and examined their gene expression patterns in adipocytes and in the adipose tissue. METHODS: Circulating apoM and adiponectin were examined in 169 men with overweight in a cross-sectional study, and 13 patients with obesity during a surgery-induced slimming program. Correlations with clinical parameters including the insulin resistance index (HOMA-IR) were analyzed. Multiple regression analyses were performed on HOMA-IR. The APOM and ADIPOQ gene expression were measured in the adipose tissue from 267 individuals with obesity and a human adipocyte cell line. RESULTS: Participants with type 2 diabetes had lower circulating adiponectin and apoM, while apoM was higher in individuals with dyslipidemia. Similar to adiponectin, apoM showed negative associations with HOMA-IR and hs-CRP (r < -0.2), and positive correlations with HDL markers (HDL-C and apoA-I, r > 0.3). Unlike adiponectin, apoM was positively associated with LDL markers (LDL-C and apoB100, r < 0.20) and negatively correlated with insulin and age (r < -0.2). The apoM was the sole negative determinant of HOMA-IR in multiple regression models, while adiponectin not contributing significantly. After surgery, the change in HOMA-IR was negatively associated with the change in circulating apoM (r = -0.71), but not with the change in adiponectin. The APOM and ADIPOQ gene expression positively correlated in adipose tissue (r > 0.44) as well as in adipocytes (r > 0.81). In adipocytes, APOM was downregulated by inflammatory factors and upregulated by adiponectin. CONCLUSIONS: The apoM rises as a new partner of adiponectin regarding insulin sensitivity. At the adipose tissue level, the adiponectin may be supported by apoM to promote a healthy adipose tissue. TRIAL REGISTRATION: NCT01277068, registered 13 January 2011; NCT02332434, registered 5 January 2015; and NCT00390637, registered 20 October 2006.

Plasma Level of ATPase Inhibitory Factor 1 and Intrinsic Capacity in Community-Dwelling Older Adults: Prospective Data From the MAPT Study.

BACKGROUND: Intrinsic capacity (IC) is a concept related to functionality that reflects healthy aging. ATPase inhibitory factor 1 (IF1) is a multifaceted protein that regulates mitochondrial oxidative phosphorylation (OXPHOS), and may be involved in IC. The objective of this study is to investigate the association between plasma levels of IF1 and IC changes in community-dwelling older adults. METHODS: Community-dwelling older adults from the Multidomain Alzheimer Preventive Trial (MAPT Study) were enrolled in this study. A composite IC score was calculated based on 4 IC domains: locomotion, psychological dimension, cognition, and vitality (with data available annually over 4 years of follow-up). Secondary analyses were conducted on the sensory domain (with data available only for 1 year of follow-up). Mixed-model linear regression adjusted for confounders was conducted. RESULTS: A total of 1 090 participants with usable IF1 values were included in the study (75.3 ± 4.4 years; 64% females). Compared to the lowest quartile, both the low- and high-intermediate IF1 quartiles were found to be cross-sectionally associated with greater composite IC scores across 4 domains (ßlow-intermediate, 1.33; 95% confidence interval [CI] 0.06-2.60 and ßhigh-intermediate, 1.78; 95% CI 0.49-3.06). In the secondary analyses, the highest quartile was found to be associated with a slower decline in composite IC scores across 5 domains over 1 year (ßhigh 1.60; 95% CI 0.06-3.15). The low- and high-intermediate IF1 quartiles were also found to be cross-sectionally associated with greater locomotion (ßlow-intermediate, 2.72; 95% CI 0.36-5.08) and vitality scores (ßhigh-intermediate, 1.59; 95% CI 0.06-3.12), respectively. CONCLUSIONS: This study is the first to demonstrate that levels of circulating IF1, a mitochondrial-related biomarker, are associated with IC composite scores in both cross-sectional and prospective analyses among community-dwelling older adults. However, further research is needed to confirm these findings and elucidate the potential underlying mechanisms that may explain these associations.

Associations between physical activity levels and ATPase inhibitory factor 1 concentrations in older adults.

BACKGROUND: Adenosine triphosphatase inhibitory factor 1 (IF1) is a key protein involved in energy metabolism. IF1 has been linked to various age-related diseases, although its relationship with physical activity (PA) remains unclear. Additionally, the apolipoprotein A-I (apoA-I), a PA-modulated lipoprotein could play a role in this relationship because it shares a binding site with IF1 on the cell-surface ATP synthase. We examined here the associations between chronic PA and plasma IF1 concentrations among older adults, and we investigated whether apoA-I mediated these associations. METHODS: In the present work, 1096 healthy adults (63.8% women) aged 70 years and over who were involved in the Multidomain Alzheimer Prevention Trial study were included. IF1 plasma concentrations (square root of ng/mL) were measured at the 1-year visit of the Multidomain Alzheimer Prevention Trial, while PA levels (square root of metabolic equivalent task min/week) were assessed using questionnaires administered each year from baseline to the 3-year visit. Multiple linear regressions were performed to investigate the associations between the first-year mean PA levels and IF1 concentrations. Mediation analyses were conducted to examine whether apoA-I mediated these associations. Mixed-effect linear regressions were carried out to investigate whether the 1-year visit IF1 concentrations predicted subsequent changes in PA. RESULTS: Multiple linear regressions indicated that first-year mean PA levels were positively associated with IF1 concentrations (B = 0.021; SE = 0.010; p = 0.043). Mediation analyses revealed that about 37.7% of this relationship was mediated by apoA-I (Bab = 0.008; SE = 0.004; p = 0.023). Longitudinal investigations demonstrated that higher concentrations of IF1 at the 1-year visit predicted a faster decline in PA levels over the subsequent 2 years (time × IF1: B = -0.148; SE = 0.066; p = 0.025). CONCLUSION: This study demonstrated that regular PA is associated with plasma IF1 concentrations, and it suggests that apoA-I partly mediates this association. Additionally, this study found that baseline concentrations of IF1 can predict future changes in PA. However, further research is needed to fully understand the mechanisms underlying these observations.

Plasma level of ATPase inhibitory factor 1 (IF1) is associated with type 2 diabetes risk in humans: A prospective cohort study.

AIM: Mitochondrial dysfunction is associated with the development of type 2 diabetes mellitus (T2DM). It is thus of clinical relevance to identify plasma biomarkers of mitochondrial dysfunction associated with the risk of T2DM. ATPase inhibitory factor 1 (IF1) endogenously inhibits mitochondrial ATP synthase activity. Here, we analyzed association of the plasma IF1 level with markers of glucose homeostasis and with the conversion to new-onset diabetes (NOD) in individuals with prediabetes. METHODS: In the IT-DIAB prospective study, the baseline plasma level of IF1 was measured in 307 participants with prediabetes. The primary outcome was the incidence of NOD within five years of follow-up. Cross-sectional analysis of the IF1 level was also done in two independent interventional studies. Correlations between plasma IF1 and metabolic parameters at baseline were assessed by Spearman's correlation coefficients, and the association with the risk of NOD was determined using Cox proportional-hazards models. RESULTS: In IT-DIAB, the mean IF1 plasma level was lower in participants who developed NOD than in those who did not (537 ± 248 versus 621 ± 313 ng/mL, P   = 0.01). The plasma IF1 level negatively correlated with clinical variables associated with obesity and insulin resistance, including the body mass index (r = -0.20, P  = 0.0005) and homeostasis model assessment of insulin resistance (HOMA-IR). (r = -0.37, P < 0.0001). Conversely, IF1 was positively associated with plasma markers of cardiometabolic health, such as HDL-C (r = 0.63, P  <  0.0001) and apoA-I (r = 0.33, P  <  0.0001). These correlations were confirmed in cross-sectional analyses. In IT-DIAB, the IF1 level was significantly associated with a lower risk of T2DM after adjustment for age, sex, and fasting plasma glucose (HR [95% CI] per 1 SD = 0.76 [0.62; 0.94], P   = 0.012). CONCLUSION: We identified for the first time the mitochondrial-related biomarker IF1 as being associated with the risk of T2DM.

The Multifaceted ATPase Inhibitory Factor 1 (IF1) in Energy Metabolism Reprogramming and Mitochondrial Dysfunction: A New Player in Age-Associated Disorders?

Significance: The mitochondrial oxidative phosphorylation (OXPHOS) system, comprising the electron transport chain and ATP synthase, generates membrane potential, drives ATP synthesis, governs energy metabolism, and maintains redox balance. OXPHOS dysfunction is associated with a plethora of diseases ranging from rare inherited disorders to common conditions, including diabetes, cancer, neurodegenerative diseases, as well as aging. There has been great interest in studying regulators of OXPHOS. Among these, ATPase inhibitory factor 1 (IF1) is an endogenous inhibitor of ATP synthase that has long been thought to avoid the consumption of cellular ATP when ATP synthase acts as an ATP hydrolysis enzyme. Recent Advances: Recent data indicate that IF1 inhibits ATP synthesis and is involved in a multitude of mitochondrial-related functions, such as mitochondrial quality control, energy metabolism, redox balance, and cell fate. IF1 also inhibits the ATPase activity of cell-surface ATP synthase, and it is used as a cardiovascular disease biomarker. Critical Issues: Although recent data have led to a paradigm shift regarding IF1 functions, these have been poorly studied in entire organisms and in different organs. The understanding of the cellular biology of IF1 is, therefore, still limited. The aim of this review was to provide an overview of the current understanding of the role of IF1 in mitochondrial functions, health, and diseases. Future Directions: Further investigations of IF1 functions at the cell, organ, and whole-organism levels and in different pathophysiological conditions will help decipher the controversies surrounding its involvement in mitochondrial function and could unveil therapeutic strategies in human pathology. Antioxid. Redox Signal. 37, 370-393.

Prediction of coronary heart disease incidence in a general male population by circulating non-coding small RNA sRNY1-5p in a nested case-control study.

During the development of atherosclerotic lesion, s-RNYs (small RNAs of about 24/34 nucleotides) are derived by the processing of long Ro-associated non-coding RNAs (RNYs) in macrophages. The levels of serum s-RNYs have been found significantly upregulated in patients with coronary heart disease (CHD) compared to age-matched CHD-free individuals. The present study aimed to examine the predictive value of serum s-RNYs for CHD events in the general male population. Within the frame of nested-case-control study, the GENES study, we measured the absolute expression of a RNY-derived small RNA, the s-RNY1-5p, in the serum of individuals (without CHD at baseline) who encountered a CHD event within 12 years of follow-up (n = 30) (Cases) and compared them to individuals who remained event-free (Controls) (n = 30). The expression of s-RNY1-5p in serum was significantly upregulated in Cases compared to Controls (p = 0.027). The proportion of CHD event-free was significantly higher among individuals with serum s-RNY1-5p below the median value (631 molecules/mL). In a multivariable model adjusted for age, smoking, hypertension, diabetes and dyslipidemia, the risk of CHD events increased more than fourfold in individuals with serum s-RNY1-5p above the median value (HR, 4.36; 95% CI 1.22-15.60). A positive association with CHD events was also observed when considering s-RNY1-5p as a continuous variable (p = 0.022). Based on our results, we conclude that serum s-RNY1-5p is an independent predictor of CHD events in a general male population and might be a relevant biomarker for early detection of cardiovascular diseases.

Treatment with PCSK9 inhibitors induces a more anti-atherogenic HDL lipid profile in patients at high cardiovascular risk.

BACKGROUND: Proprotein Convertase Subtilisin/Kexin type 9 inhibitors (PCSK9-I) have been reported to cause a moderate increase in high-density lipoprotein (HDL) cholesterol in human studies. We thus evaluated the effect of two approved PCSK9-I on the concentration and lipid composition of HDL particle subclasses. SUBJECTS AND METHODS: 95 patients (62.8 ± 10.3 years old, 58% men), with or without statin and/or ezetimibe treatment and eligible for PCSK9-I therapy, received either evolocumab (140 mg) or alirocumab (75 or 150 mg). Their HDL particle profiles were measured by NMR spectroscopy at baseline and after 4 weeks of PCSK9-I treatment. RESULTS: PCSK9-I treatment increased the level of HDL-C by 7%. The level of medium-sized HDL particles (M-HDL-P) increased (+8%) while the level of XL-HDL-P decreased (-19%). The lipid core composition was altered in the smaller S- and M-HDL-P, with a reduction in triglycerides (TG) and an enrichment in cholesterol esters (CE), whereas the for the larger XL- and L-HDL-P the relative CE content decreased and the TG content increased. Ezetimibe therapy differentially impacted the HDL particle distribution, independently of statin use, with an increase in S-HDL-P in patients not receiving ezetimibe. CONCLUSIONS: As S- and M-HDL-P levels are inversely related to cardiovascular risk, PCSK9-I treatment may result in a more atheroprotective HDL particle profile, particularly in patients not concomitantly treated with ezetimibe.

A reference measurement of circulating ATPase inhibitory factor 1 (IF1) in humans by LC-MS/MS: Comparison with conventional ELISA.

ATPase inhibitory factor 1 (IF1) is a 9.5 kDa protein that binds to mitochondrial and plasma membrane ATP synthase and selectively inhibits ATP hydrolysis. Recently, IF1 was identified in systemic circulation in humans. IF1 appeared as an independent determinant of HDL-cholesterol with lower levels in coronary heart disease (CHD) patients. Moreover, IF1 was also found to negatively associate with mortality in these patients, supporting the notion that circulating IF1 could be a promising biomarker of cardiovascular disease. However, in previous studies, IF1 was quantified by a non-standardized competitive enzyme-linked immunosorbent assay (ELISA). Herein, we have validated a liquid chromatography-tandem mass spectrometry method (LC-MS/MS) enabling the accurate quantification of IF1 in human plasma. Plasma IF1 was trypsin-digested through an optimized procedure before LC-MS/MS analysis. The method was successfully validated over 4 independent experiments into the range of 100-1500 ng/mL. Intra- and inter-assay variation coefficients had never exceeded 14.2% and accuracy ranged between 95% and 102% for the selected EAGGAFGK peptide marker. Subsequently, the results of the LC-MS/MS method were compared with those obtained using ELISA in 204 individuals from the GENES study. We found that IF1 plasma levels obtained using both techniques were strongly correlated (r = 0.89, p < 0.0001), while the Bland-Altman plot did not indicate any major statistically significant differences. To clinically validate LC-MS/MS, we confirmed the positive correlation between IF1 plasma levels and HDL-cholesterol (r = 0.38, p < 0.0001). Besides, we found lower IF1 plasma levels in CHD patients compared to controls (431 ± 132 ng/mL and 555 ± 173 ng/mL, respectively; p < 0.0001). Hence, it can be concluded that the presented LC-MS/MS analytical method provides a highly specific strategy for IF1 quantification in human plasma and could be proposed as a reference method.

Serum level of HDL particles are independently associated with long-term prognosis in patients with coronary artery disease: The GENES study.

HDL-Cholesterol (HDL-C) is not an accurate surrogate marker to measure the cardioprotective functions of HDL in coronary artery diseases (CAD) patients. Hence, measurement of other HDL-related parameters may have prognostic superiority over HDL-C. In this work, we examined the predictive value of HDL particles profile for long-term mortality in CAD patients and to compare its informative value to that of HDL-C and apoA-I. HDL particles profiles were measured by nuclear magnetic resonance (NMR) spectroscopy in 214 male participants with stable CAD (45-74 years). Median follow up was 12.5 years with a 36.4% mortality rate. Cardiovascular mortality accounted for 64.5%. Mean concentrations of total HDL particles (HDL-P), small-sized HDL (SHDL-P) and apoA-I were lower in deceased than in surviving patients whereas no difference was observed according to HDL-C and large HDL particles. All NMR-HDL measures were correlated between themselves and with other HDL markers (HDL-C, apoA-I and LpA-I). In a multivariate model adjusted for cardiovascular risk factors and bioclinical variables, HDL-P and SHDL-P displayed the strongest inverse association with all-cause and cardiovascular mortality. Weaker associations were recorded for apoA-I. Based on our results, we conclude that HDL particle profile measured by NMR spectroscopy should be considered to better stratify risk in population at high risk or in the setting of pharmacotherapy.

Common p2y13 polymorphisms are associated with plasma inhibitory factor 1 and lipoprotein(a) concentrations, heart rate and body fat mass: The GENES study.

BACKGROUND: The P2Y13 purinergic receptor regulates hepatic high-density lipoprotein uptake and biliary sterol secretion; it acts downstream of the membrane ecto-F1-adenosine triphosphatase, which generates extracellular adenosine diphosphate that selectively activates P2Y13, resulting in high-density lipoprotein endocytosis. Previous studies have shown that the serum concentration of the F1-adenosine triphosphatase inhibitor inhibitory factor 1 is negatively associated with cardiovascular risk. AIM: To evaluate whether p2y13 genetic variants affect cardiovascular risk. METHODS: Direct sequencing of the p2y13 coding and flanking regions was performed in a subcohort of 168 men aged 45-74 years with stable coronary artery disease and 173 control subjects from the GENES study. The two most frequent mutations, rs3732757 and rs1466684, were genotyped in 767 patients with coronary artery disease and 789 control subjects, and their association with cardiovascular risk markers was analysed. RESULTS: Carriers of the rs3732757 261T and rs1466684 557G alleles represented 9% and 27.5% of the entire population, respectively. The allele frequencies were identical in patients with coronary artery disease and control subjects. The presence of 261T was associated with higher concentrations of plasma lipoprotein A-I and inhibitory factor 1, increased fat mass and a lower heart rate. Moreover, the proportion of patients with coronary artery disease with a pejorative systolic ankle-brachial index was lower in carriers of the 261T allele. In both populations, the 557G allele was associated with increased concentrations of lipoprotein(a), and an allele dose effect was observed. CONCLUSIONS: Two frequent p2y13 variants are associated with specific bioclinical markers of cardiovascular risk. Although neither one of these variants appears to be related to the development of atherosclerotic disease, they may modulate the risk of additional cardiovascular complications.

Serum inhibitory factor 1, high-density lipoprotein and cardiovascular diseases.

PURPOSE OF REVIEW: The atheroprotective properties of HDL are supported by epidemiological and preclinical research. However, the results of interventional trials paradoxically indicate that drugs increasing HDL-cholesterol (HDL-C) do not reduce coronary artery disease (CAD) risk. Moreover, Mendelian randomization studies have shown no effect of HDL-C-modifying variants on CAD outcome. Thus, the protective effects of HDL particles are more governed by their functional status than their cholesterol content. In this context, any successful clinical exploitation of HDL will depend on the identification of HDL-related biomarkers, better than HDL-C level, for assessing cardiovascular risk and monitoring responses to treatment. RECENT FINDINGS: Recent studies have enlightened the role of ecto-F1-ATPase as a cell surface receptor for apoA-I, the major apolipoprotein of HDL, involved in the important metabolic and vascular atheroprotective functions of HDL. In the light of these findings, the clinical relevance of ecto-F1-ATPase in humans has recently been supported by the identification of serum F1-ATPase inhibitor (IF1) as an independent determinant of HDL-C, CAD risk and cardiovascular mortality in CAD patients. SUMMARY: Serum IF1 measurement might be used as a novel HDL-related biomarker to better stratify risk in high-risk populations or to determine pharmacotherapy.

High-density lipoprotein subclass profile and mortality in patients with coronary artery disease: Results from the GENES study.

BACKGROUND: High-density lipoproteins (HDLs) are highly heterogeneous particles, and the specific contribution of each subclass to the prediction of clinical outcome in coronary artery disease (CAD) remains controversial. OBJECTIVE: To examine the relationship between HDL subclass profile and mortality in patients with CAD, using a new and rapid electrophoretic quantitative method for the assessment of HDL particle size phenotype. METHODS: We investigated 403 patients with CAD admitted for cardiovascular examination in the context of evaluation and management of CAD. HDL subclass distribution was analysed using the Quantimetrix Lipoprint® HDL system. Cumulative survival of patients according to lipid variables was determined by the Kaplan-Meier method. The relationship between baseline variables and outcome criteria was assessed using Cox proportional hazards regression analysis. RESULTS: During follow-up (9.8±3.1 years) the mortality rate was 31.0%; 60.8% of deaths were related to CAD. The concentration of total HDL cholesterol was similar in deceased patients (42±13mg/dL) and alive patients (43±12mg/dL); the concentrations of small, intermediate and large HDL cholesterol subclasses were not significantly different in alive and deceased patients (P=0.17, P=0.34 and P=0.81, respectively). We did not observe any independent associations between overall or cardiovascular mortality and total HDL cholesterol or any HDL subclass. However, heart rate, left ventricular ejection fraction and severity score for coronary atherosclerosis were more associated with mortality than classical cardiovascular risk factors. CONCLUSIONS: HDL subclass profile is not associated with mortality in patients with CAD. Further investigations linking HDL subclass repartition with prediction of residual cardiovascular risk are required.

Serum levels of mitochondrial inhibitory factor 1 are independently associated with long-term prognosis in coronary artery disease: the GENES Study.

BACKGROUND: Epidemiological and observational studies have established that high-density lipoprotein cholesterol (HDL-C) is an independent negative cardiovascular risk factor. However, simple measurement of HDL-C levels is no longer sufficient for cardiovascular risk assessment. Therefore, there is a critical need for novel non-invasive biomarkers that would display prognostic superiority over HDL-C. Cell surface ecto-F1-ATPase contributes to several athero-protective properties of HDL, including reverse cholesterol transport and vascular endothelial protection. Serum inhibitory factor 1 (IF1), an endogenous inhibitor of ecto-F1-ATPase, is an independent determinant of HDL-C associated with low risk of coronary artery disease (CAD). This work aimed to examine the predictive value of serum IF1 for long-term mortality in CAD patients. Its informative value was compared to that of HDL-C. METHOD: Serum IF1 levels were measured in 577 male participants with stable CAD (age 45-74 years) from the GENES (Genetique et ENvironnement en Europe du Sud) study. Vital status was yearly assessed, with a median follow-up of 11 years and a 29.5 % mortality rate. Cardiovascular mortality accounted for the majority (62.4 %) of deaths. RESULTS: IF1 levels were positively correlated with HDL-C (r s = 0.40; P < 0.001) and negatively with triglycerides (r s = -0.21, P < 0.001) and CAD severity documented by the Gensini score (r s = -0.13; P < 0.01). Total and cardiovascular mortality were lower at the highest quartiles of IF1 (HR = 0.55; 95 % CI, 0.38-0.89 and 0.50 (0.28-0.89), respectively) but not according to HDL-C. Inverse associations of IF1 with mortality remained significant, after multivariate adjustments for classical cardiovascular risk factors (age, smoking, physical activity, waist circumference, HDL-C, dyslipidemia, hypertension, and diabetes) and for powerful biological and clinical variables of prognosis, including heart rate, ankle-brachial index and biomarkers of cardiac diseases. The 10-year mortality was 28.5 % in patients with low IF1 (<0.42 mg/L) and 21.4 % in those with high IF1 (≥0.42 mg/L, P < 0.02). CONCLUSIONS: We investigated for the first time the relation between IF1 levels and long-term prognosis in CAD patients, and found an independent negative association. IF1 measurement might be used as a novel HDL-related biomarker to better stratify risk in populations at high risk or in the setting of pharmacotherapy.

RNY-derived small RNAs as a signature of coronary artery disease.

BACKGROUND: Data from next generation sequencing technologies uncovered the existence of many classes of small RNAs. Recent studies reported that small RNAs are released by cells and can be detected in the blood. In this report, we aimed to discover the occurrence of novel circulating small RNAs in coronary artery disease (CAD). METHODS: We used high-throughput sequencing of small RNAs from human and mouse apoptotic primary macrophages, and analyzed the data by empirical Bayes moderated t-statistics to assess differential expression and the Benjamini and Hochberg method to control the false discovery rate. Results were then confirmed by Northern blot and RT-qPCR in foam cells and in two animal models for atherosclerosis, namely ApoE(-/-) and Ldlr(-/-) mouse lines. Quantitative RT-PCR to detect identified small RNAs, the RNY-derived small RNAs, was performed using sera of 263 patients with CAD compared to 514 matched healthy controls; the Student t-test was applied to statistically assess differences. Associations of small RNAs with clinical characteristics and biological markers were tested using Spearman's rank correlations, while multivariate logistic regressions were performed to test the statistical association of small RNA levels with CAD. RESULTS: Here, we report that, in macrophages stimulated with pro-apoptotic or pro-atherogenic stimuli, the Ro-associated non-coding RNAs, called RNYs or Y-RNAs, are processed into small RNAs (~24-34 nt) referred to as small-RNYs (s-RNYs), including s-RNY1-5p processed from RNY1. A significant upregulation of s-RNY expression was found in aortic arches and blood plasma from ApoE(-/-) and Ldlr(-/-) mice and in serum from CAD patients (P <0.001). Biostatistical analysis revealed a positive association of s-RNY1-5p with hs-CRP and ApoB levels; however, no statistical interaction was found between either of these two markers and s-RNY1-5p in relation to the CAD status. Levels of s-RNY1-5p were also independent from statin and fibrate therapies. CONCLUSION: Our results position the s-RNY1-5p as a relevant novel independent diagnostic biomarker for atherosclerosis-related diseases. Measurement of circulating s-RNY expression would be a valuable companion diagnostic to monitor foam cell apoptosis during atherosclerosis pathogenesis and to evaluate patient's responsiveness to future therapeutic strategies aiming to attenuate apoptosis in foam cells in advanced atherosclerotic lesions.

Increased atherosclerosis in P2Y13/apolipoprotein E double-knockout mice: contribution of P2Y13 to reverse cholesterol transport.

AIMS: High-density lipoproteins (HDLs) protect against atherosclerosis mainly due to their function in hepatobiliary reverse cholesterol transport (RCT). This is a process whereby excess cholesterol from peripheral tissues is transported by HDL particles to the liver for further metabolism and biliary excretion. Hepatic uptake of HDL holoparticles involves the P2Y13 receptor, independently of the selective cholesteryl ester uptake mediated by scavenger receptor class B, type I (SR-BI). Accordingly, P2Y13-deficient mice (P2Y13 (-/-)) have impaired RCT. This study assessed whether P2Y13 deficiency would affect atherosclerotic development. METHODS AND RESULTS: P2Y13 (-/-) mice were crossbred with atherosclerosis-prone apoE(-/-) mice. When 15 weeks old, P2Y13 (-/-)/apoE(-/-) mice had more aortic sinus lesions than apoE(-/-) mice. Bone marrow transplantation showed that the absence of the P2Y13 receptor in blood cells did not lead to significantly greater atherosclerotic plaque size formation compared with control apoE(-/-) reconstituted animals. Conversely, the absence of the P2Y13 receptor, except in blood cells, resulted in lesion sizes similar to that in P2Y13 (-/-)/apoE(-/-) reconstituted mice, pointing to a role for non-haematopoietic-derived P2Y13. Unexpectedly, P2Y13 (-/-)/apoE(-/-) mice displayed a lower HDL-cholesterol level than apoE(-/-) mice, which might be due to greater SR-BI expression in the liver. However, P2Y13 deficiency in apoE(-/-) mice was translated into reduced biliary and faecal sterol excretion and impaired RCT from macrophage to faeces, suggesting that an alteration in hepatobiliary RCT could be solely responsible for the greater atherosclerosis observed. CONCLUSION: The P2Y13 receptor protects against atherosclerosis, primarily through its role in hepatobiliary RCT.

Ecto-F1-ATPase/P2Y pathways in metabolic and vascular functions of high density lipoproteins.

The atheroprotective property of High Density Lipoprotein (HDL) is supported by many epidemiological studies and cellular and in vivo approaches on animal models. While the anti-atherogenic effects of HDL are thought to derive primarily from its role in reverse cholesterol transport, together with anti-inflammatory, anti-oxidant, anti-thrombotic and cytoprotective properties, the mechanisms that support these effects are still not completely understood. However, many advances in identifying the cellular partners involved in HDL functions have been made over the last two decades. This review highlights the diverse roles of the HDL receptor ecto-F1-ATPase coupled to purinergic P2Y receptors in the modulation of important metabolic and vascular functions of HDL. On hepatocytes, the ecto-F1-ATPase is coupled to P2Y13 receptor and contributes to HDL holoparticle endocytosis. On endothelial cells, ecto-F1-ATPase/P2Ys pathway is involved in HDL-mediated endothelial protection and HDL transcytosis. The clinical relevance of this F1-ATPase/P2Ys axis in humans has recently been supported by the identification of serum F1-ATPase inhibitor (IF1) as an independent determinant of HDL-Cholesterol (HDL-C) and coronary heart disease risk. Therapeutic strategies targeting F1-ATPase/P2Y pathways for the treatment of atherosclerosis are currently being explored.

Targeting high-density lipoproteins: update on a promising therapy.

Numerous epidemiological studies have demonstrated the atheroprotective roles of high density lipoproteins (HDL), so that HDL is established as an independent negative risk factor. The protective effect of HDL against atherosclerosis is mainly attributed to their capacity to bring peripheral excess cholesterol back to the liver for further elimination into the bile. In addition, HDL can exert other protective functions on the vascular wall, through their anti-inflammatory, antioxidant, antithrombotic and cytoprotective properties. HDL-targeted therapy is thus an innovative approach against cardiovascular risk and atherosclerosis. These pleiotropic atheroprotective properties of HDL have led experts to believe that "HDL-related therapies" represent the most promising next step in fighting against atherosclerosis. However, because of the heterogeneity of HDL functions, targeting HDL is not a simple task and HDL therapies that lower cardiovascular risk are NOT yet available. In this paper, an overview is presented about the therapeutic strategies currently under consideration to raise HDL levels and/or functions. Recently, clinical trials of drugs targeting HDL-C levels have disappointingly failed, suggesting that HDL functions through specific mechanisms should be targeted rather than increasing per se HDL levels.

Early loss of bone mineral density is correlated with a gain of fat mass in patients starting a protease inhibitor containing regimen: the prospective Lipotrip study.

BACKGROUND: HIV-infected patients starting antiretroviral treatment (ART) experience deep and early disorders in fat and bone metabolism, leading to concomitant changes in fat mass and bone mineral density. METHODS: We conducted a prospective study in treatment-naive HIV-infected patients randomized to receive two nucleoside reverse transcriptase inhibitors in combination with either a protease inhibitor (PI) or a non-nucleosidic reverse transcriptase inhibitor (NNRTI), to evaluate early changes in body composition, bone mineral density and metabolic markers as differentially induced by antiretroviral therapies. We measured changes in markers of carbohydrate, of fat and bone metabolism, and, using dual-emission X-ray absorptiometry (DXA), body composition and bone mineral density (BMD). Complete data on changes between baseline and after 21 months treatment were available for 35 patients (16 in the PI group and 19 in the NNRTI group). RESULTS: A significant gain in BMI and in total and lower limb fat mass was recorded only in patients receiving PI. A loss of lumbar BMD was observed in both groups, being higher with PI. Plasma markers of bone metabolism (alkaline phosphatase, osteocalcin, collagen crosslaps) and levels of parathormone and of 1,25diOH-vitamin D3 significantly increased in both groups, concomitant with a decline in 25OH-vitamin D3. Lipids and glucose levels increased in both groups but rise in triglyceride was more pronounced with PI. A correlation between loss of BMD and gain of fat mass is observed in patients starting PI. CONCLUSIONS: We evidenced an early effect of ART on lipid and bone metabolisms. PI lead to a significant gain in fat mass correlated with a sharp drop in BMD but active bone remodelling is evident with all antiretroviral treatments, associated with low vitamin D levels and hyperparathyroidism. In parallel, signs of metabolic restoration are evident. However, early increases in lean and fat mass, triglycerides, waist circumference and leptin are much more pronounced with PI.

Association of hepatic lipase -514T allele with coronary artery disease and ankle-brachial index, dependence on the lipoprotein phenotype: the GENES study.

OBJECTIVES: Relationship between hepatic lipase (LIPC) polymorphism and coronary artery disease (CAD) has often led to contradictory results. We studied this relation by genotyping rs1800588 in the LIPC promoter in a case-control study on CAD (the GENES study). We also investigated the relationship between this polymorphism and the ankle-brachial index (ABI), which is predictive of atherosclerosis progression and complications in patients at high cardiovascular risk. METHODS: 557 men aged 45-74 with stable coronary artery disease and 560 paired controls were genotyped for rs1800588. Medical data, clinical examination including determination of ABI and biological measurements related to cardiovascular risk factors enabled multivariate analyses and multiple adjustments. RESULTS: CAD cases showed a higher T-allele frequency than controls (0.246 vs 0.192, p = 0.003). An interaction has been found between LIPC polymorphism and triglycerides (TG) levels regarding risk of CAD: TT-homozigosity was associated with an Odds ratio (OR) of 6.4 (CI: 1.8-22.3) when TG were below 1.5 g/L, but no association was found at higher TG levels (OR = 1.34, CI: 0.3-5.9). The distribution of LIPC genotypes was compared between CAD patients with normal or abnormal ABI and impact of LIPC polymorphism on ABI was determined. Following multiple adjustments, association of the T-allele with pejorative ABI (<0.90) was significant for heterozygotes and for all T-carriers (OR = 1.55, CI: 1.07-2.25). CONCLUSION: The -514T LIPC allele is associated with CAD under normotriglyceridemic conditions and constitutes an independent determinant of pejorative ABI in coronary patients.