Consensus document on Lipoprotein(a) from the Italian Society for the Study of Atherosclerosis (SISA)

AIMS

In view of the consolidating evidence on the causal role of Lp(a) in cardiovascular disease, the Italian Society for the Study of Atherosclerosis (SISA) has assembled a consensus on Lp(a) genetics and epidemiology, together with recommendations for its measurement and current and emerging therapeutic approaches to reduce its plasma levels. Data on the Italian population are also provided.

DATA SYNTHESIS

Lp(a) is constituted by one apo(a) molecule and a lipoprotein closely resembling to a low-density lipoprotein (LDL). Its similarity with an LDL, together with its ability to carry oxidized phospholipids are considered the two main features making Lp(a) harmful for cardiovascular health. Plasma Lp(a) concentrations vary over about 1000 folds in humans and are genetically determined, thus they are quite stable in any individual. Mendelian Randomization studies have suggested a causal role of Lp(a) in atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis and observational studies indicate a linear direct correlation between cardiovascular disease and Lp(a) plasma levels. Lp(a) measurement is strongly recommended once in a patient's lifetime, particularly in FH subjects, but also as part of the initial lipid screening to assess cardiovascular risk. The apo(a) size polymorphism represents a challenge for Lp(a) measurement in plasma, but new strategies are overcoming these difficulties. A reduction of Lp(a) levels can be currently attained only by plasma apheresis and, moderately, with PCSK9 inhibitor treatment.

CONCLUSIONS

Awaiting the approval of selective Lp(a)-lowering drugs, an intensive management of the other risk factors for individuals with elevated Lp(a) levels is strongly recommended.

Effect of diet and genotype on the miRNome of mice with altered lipoprotein metabolism

The molecular mechanism by which lipid/lipoprotein biosynthesis is regulated in mammals involves a very large number of genes that are subject to multiple levels of regulation. miRNAs are recognized contributors to lipid homeostasis at the post-transcriptional level, although the elucidation of their role is made difficult by the multiplicity of their targets and the ability of more miRNAs to affect the same mRNAs. In this study, an evaluation of how miRNA expression varies in organs playing a key role in lipid/lipoprotein metabolism was conducted in control mice and in two mouse models carrying genetic ablations which differently affect low-density lipoprotein metabolism. Mice were fed a lipid-poor standard diet and a diet enriched in cholesterol and saturated fat. The results obtained showed that there are no miRNAs whose expression constantly vary with dietary or genetic changes. Furthermore, it appears that diet, more than genotype, impacts on organ-specific miRNA expression profiles.

Effect of Diets on Plasma and Aorta Lipidome: A Study in the apoE Knockout Mouse Model

SCOPE

Specific lipid molecules circulating in plasma at low concentrations have emerged as biomarkers of atherosclerotic risk. The aim of the present study is that of evaluating, in an athero-prone mouse model, how different diets can affect plasma and aorta lipidome.

METHODS AND RESULTS

Thirty-six apoE knockout mice are divided in three groups and feed 12 weeks with diets differing for cholesterol and fatty acid content. Atherosclerosis is measured at the aortic sinus and aorta. Lipids are quantified in plasma and aorta with mass spectrometry. The cholesterol content of the diets is the main driver of lipid accumulation in plasma and aorta. The fatty acid composition of the diets affects plasma levels both of essential (linoleic acid) and nonessential (myristic and arachidonic acid) ones. Lipidomics show a comparable distribution, in plasma and aorta, of the main lipid components of oxidized LDL, including cholesteryl esters and lysophosphatidylcholines. Interestingly, lactosylceramide, glucosyl/galactosylceramide, and individual ceramide species are found to accumulate in diseased aortic segments.

CONCLUSION

Both the cholesterol and fatty acid content of the diets profoundly affect plasma lipidome. Aorta lipidome is likewise affected with the accumulation of specific lipids known as markers of atherosclerosis.

Lack of ApoA-I in ApoEKO Mice Causes Skin Xanthomas, Worsening of Inflammation, and Increased Coronary Atherosclerosis in the Absence of Hyperlipidemia

Background:

HDL (high-density lipoprotein) and its major protein component, apoA-I (apolipoprotein A-I), play a unique role in cholesterol homeostasis and immunity. ApoA-I deficiency in hyperlipidemic, atheroprone mice was shown to drive cholesterol accumulation and inflammatory cell activation/proliferation. The present study was aimed at investigating the impact of apoA-I deficiency on lipid deposition and local/systemic inflammation in normolipidemic conditions.

Methods:

ApoE deficient mice, apoE/apoA-I double deficient (DKO) mice, DKO mice overexpressing human apoA-I, and C57Bl/6J control mice were fed normal laboratory diet until 30 weeks of age. Plasma lipids were quantified, atherosclerosis development at the aortic sinus and coronary arteries was measured, skin ultrastructure was evaluated by electron microscopy. Blood and lymphoid organs were characterized through histological, immunocytofluorimetric, and whole transcriptome analyses.

Results:

DKO were characterized by almost complete HDL deficiency and by plasma total cholesterol levels comparable to control mice. Only DKO showed xanthoma formation and severe inflammation in the skin-draining lymph nodes, whose transcriptome analysis revealed a dramatic impairment in energy metabolism and fatty acid oxidation pathways. An increased presence of CD4⁺ T effector memory cells was detected in blood, spleen, and skin-draining lymph nodes of DKO. A worsening of atherosclerosis at the aortic sinus and coronary arteries was also observed in DKO versus apoE deficient. Human apoA-I overexpression in the DKO background was able to rescue the skin phenotype and halt atherosclerosis development.

Conclusions:

HDL deficiency, in the absence of hyperlipidemia, is associated with severe alterations of skin morphology, aortic and coronary atherosclerosis, local and systemic inflammation.

reString: an open-source Python software to perform automatic functional enrichment retrieval, results aggregation and data visualization

Functional enrichment analysis is an analytical method to extract biological insights from gene expression data, popularized by the ever-growing application of high-throughput techniques. Typically, expression profiles are generated for hundreds to thousands of genes/proteins from samples belonging to two experimental groups, and after ad-hoc statistical tests, researchers are left with lists of statistically significant entities, possibly lacking any unifying biological theme. Functional enrichment tackles the problem of putting overall gene expression changes into a broader biological context, based on pre-existing knowledge bases of reference: database collections of known expression regulation, relationships and molecular interactions. STRING is among the most popular tools, providing both protein–protein interaction networks and functional enrichment analysis for any given set of identifiers. For complex experimental designs, manually retrieving, interpreting, analyzing and abridging functional enrichment results is a daunting task, usually performed by hand by the average wet-biology researcher. We have developed reString, a cross-platform software that seamlessly retrieves from STRING functional enrichments from multiple user-supplied gene sets, with just a few clicks, without any need for specific bioinformatics skills. Further, it aggregates all findings into human-readable table summaries, with built-in features to easily produce user-customizable publication-grade clustermaps and bubble plots. Herein, we outline a complete reString protocol, showcasing its features on a real use-case.

Rupatadine treatment is associated to atherosclerosis worsening and altered T lymphocyte recruitment

No Abstract.

Identification and Characterization of Human Observational Studies in Nutritional Epidemiology on Gut Microbiomics for Joint Data Analysis

In any research field, data access and data integration are major challenges that even large, well-established consortia face. Although data sharing initiatives are increasing, joint data analyses on nutrition and microbiomics in health and disease are still scarce. We aimed to identify observational studies with data on nutrition and gut microbiome composition from the Intestinal Microbiomics (INTIMIC) Knowledge Platform following the findable, accessible, interoperable, and reusable (FAIR) principles. An adapted template from the European Nutritional Phenotype Assessment and Data Sharing Initiative (ENPADASI) consortium was used to collect microbiome-specific information and other related factors. In total, 23 studies (17 longitudinal and 6 cross-sectional) were identified from Italy (7), Germany (6), Netherlands (3), Spain (2), Belgium (1), and France (1) or multiple countries (3). Of these, 21 studies collected information on both dietary intake (24 h dietary recall, food frequency questionnaire (FFQ), or Food Records) and gut microbiome. All studies collected stool samples. The most often used sequencing platform was Illumina MiSeq, and the preferred hypervariable regions of the 16S rRNA gene were V3–V4 or V4. The combination of datasets will allow for sufficiently powered investigations to increase the knowledge and understanding of the relationship between food and gut microbiome in health and disease.

Myocardial overexpression of ANKRD1 causes sinus venosus defects and progressive diastolic dysfunction

AIMS

Increased Ankyrin Repeat Domain 1 (ANKRD1) levels linked to gain of function mutations have been associated to total anomalous pulmonary venous return and adult cardiomyopathy occurrence in humans. The link between increased ANKRD1 level and cardiac structural and functional disease is not understood. To get insight into this problem, we have generated a gain of function ANKRD1 mouse model by overexpressing ANKRD1 in the myocardium.

METHODS AND RESULTS

Ankrd1 is expressed non-homogeneously in the embryonic myocardium, with a dynamic nucleo-sarcomeric localization in developing cardiomyocytes. ANKRD1 transgenic mice present sinus venosus defect, which originates during development by impaired remodelling of early embryonic heart. Adult transgenic hearts develop diastolic dysfunction with preserved ejection fraction, which progressively evolves into heart failure, as shown histologically and haemodynamically. Transgenic cardiomyocyte structure, sarcomeric assembly, and stability are progressively impaired from embryonic to adult life. Postnatal transgenic myofibrils also present characteristic functional alterations: impaired compliance at neonatal stage and impaired lusitropism in adult hearts. Altogether, our combined analyses suggest that impaired embryonic remodelling and adult heart dysfunction in ANKRD1 transgenic mice present a common ground of initial cardiomyocyte defects, which are exacerbated postnatally. Molecular analysis showed transient activation of GATA4-Nkx2.5 transcription in early transgenic embryos and subsequent dynamic transcriptional modulation within titin gene.

CONCLUSIONS

ANKRD1 is a fine mediator of cardiomyocyte response to haemodynamic load in the developing and adult heart. Increased ANKRD1 levels are sufficient to initiate an altered cellular phenotype, which is progressively exacerbated into a pathological organ response by the high ventricular workload during postnatal life. Our study defines for the first time a unifying picture for ANKRD1 role in heart development and disease and provides the first mechanistic link between ANKRD1 overexpression and cardiac disease onset.

Aortic Gene Expression Profiles Show How ApoA-I Levels Modulate Inflammation, Lysosomal Activity, and Sphingolipid Metabolism in Murine Atherosclerosis

OBJECTIVE

HDL (high-density lipoprotein) particles are known to possess several antiatherogenic properties that include the removal of excess cholesterol from peripheral tissues, the maintenance of endothelial integrity, antioxidant, and anti-inflammatory activities. ApoA-I overexpression in apoE-deficient (EKO) mice has been shown to increase HDL levels and to strongly reduce atherosclerosis development. The aim of the study was to investigate gene expression patterns associated with atherosclerosis development in the aorta of EKO mice and how HDL plasma levels relate to gene expression patterns at different stages of atherosclerosis development and with different dietary treatments. Approach and Results: Eight-week-old EKO mice, EKO mice overexpressing human apoA-I, and wild-type mice as controls were fed either normal laboratory or Western diet for 6 or 22 weeks. Cholesterol distribution among lipoproteins was evaluated, and atherosclerosis of the aorta was quantified. High-throughput sequencing technologies were used to analyze the transcriptome of the aorta of the 3 genotypes in each experimental condition. In addition to the well-known activation of inflammation and immune response, the impairment of sphingolipid metabolism, phagosome-lysosome system, and osteoclast differentiation emerged as relevant players in atherosclerosis development. The reduced atherosclerotic burden in the aorta of EKO mice expressing high levels of apoA-I was accompanied by a reduced activation of immune system markers, as well as reduced perturbation of lysosomal activity and a better regulation of the sphingolipid synthesis pathway.

CONCLUSIONS

ApoA-I modulates atherosclerosis development in the aorta of EKO mice affecting the expression of pathways additional to those associated with inflammation and immune response.

liputils: a Python module to manage individual fatty acid moieties from complex lipids

Lipidomic analyses address the problem of characterizing the lipid components of given cells, tissues and organisms by means of chromatographic separations coupled to high-resolution, tandem mass spectrometry analyses. A number of software tools have been developed to help in the daunting task of mass spectrometry signal processing and cleaning, peak analysis and compound identification, and a typical finished lipidomic dataset contains hundreds to thousands of individual molecular lipid species. To provide researchers without a specific technical expertise in mass spectrometry the possibility of broadening the exploration of lipidomic datasets, we have developed liputils, a Python module that specializes in the extraction of fatty acid moieties from individual molecular lipids. There is no prerequisite data format, as liputils extracts residues from RefMet-compliant textual identifiers and from annotations of other commercially available services. We provide three examples of real-world data processing with liputils, as well as a detailed protocol on how to readily process an existing dataset that can be followed with basic informatics skills.

Fat-Shaped Microbiota Affects Lipid Metabolism, Liver Steatosis, and Intestinal Homeostasis in Mice Fed a Low-Protein Diet

SCOPE

Protein malnutrition is characterized by stunted growth, hepatic steatosis and a damaged gut mucosal architecture. Since high-fat shaped gut microbiota (HFM) has an increased ability in providing nutrients and energy from food to the host, the aim of this study is to determine whether such a microbiota could beneficially impact on the consequences of malnutrition.

METHODS AND RESULTS

The cecal content of specific pathogen free C57Bl/6J mice fed a high-fat diet or a low-protein diet is transplanted in two groups of germ-free C57Bl/6J recipient mice, which are subsequently fed a low-protein diet for 8 weeks. Body weight gain is comparable between the two groups of microbiota-recipient mice. The HFM led to a worsening of microvesicular steatosis and a decrease of plasma lipids compared to the low-protein shaped microbiota. In the small intestine of mice receiving the HFM, although significant histological differences are not observed, the expression of antimicrobial genes promoting oxidative stress and immune response at the ileal epithelium (Duox2, Duoxa2, Saa1, Ang4, Defa5) is increased.

CONCLUSION

The transplant of HFM in mice fed a low-protein diet represents a noxious stimulus for the ileal mucosa and impairs hepatic lipoprotein secretion, favoring the occurrence of hepatic microvesicular steatosis.

The Gut Microbiota Affects Host Pathophysiology as an Endocrine Organ: A Focus on Cardiovascular Disease

It is widely recognized that the microorganisms inhabiting our gastrointestinal tract-the gut microbiota-deeply affect the pathophysiology of the host. Gut microbiota composition is mostly modulated by diet, and gut microorganisms communicate with the different organs and tissues of the human host by synthesizing hormones and regulating their release. Herein, we will provide an updated review on the most important classes of gut microbiota-derived hormones and their sensing by host receptors, critically discussing their impact on host physiology. Additionally, the debated interplay between microbial hormones and the development of cardiovascular disease will be thoroughly analysed and discussed.

Fenretinide treatment accelerates atherosclerosis development in apoE-deficient mice in spite of beneficial metabolic effects

BACKGROUND AND PURPOSE

Fenretinide, a synthetic retinoid derivative first investigated for cancer prevention and treatment, has been shown to ameliorate glucose tolerance, improve plasma lipid profile and reduce body fat mass. These effects, together with its ability to inhibit ceramide synthesis, suggest that fenretinide may have an anti-atherosclerotic action.

EXPERIMENTAL APPROACH

To this aim, nine-week-old apoE-knockout (EKO) female mice were fed for twelve weeks a Western diet, without (control) or with (0.1% w/w) fenretinide. As a reference, wild-type (WT) mice were treated similarly. Growth and metabolic parameters were monitored throughout the study. Atherosclerosis development was evaluated in the aorta and at the aortic sinus. Blood and lymphoid organs were further characterized with thorough cytological/histological and immunocytofluorimetric analyses.

KEY RESULTS

Fenretinide treatment significantly lowered body weight, glucose levels and plasma levels of total cholesterol, triglycerides, and phospholipids. In the liver, fenretinide remarkably reduced hepatic glycogenosis and steatosis driven by the Western diet. Treated spleens were abnormally enlarged, with severe follicular atrophy and massive extramedullary haematopoiesis. Severe renal hemosiderin deposition was observed in treated EKO mice. Treatment resulted in a threefold increase of total leukocytes (WT and EKO) and raised the activated/resting monocyte ratio in EKO mice. Finally, atherosclerosis development was markedly increased at the aortic arch, thoracic and abdominal aorta of fenretinide-treated mice.

CONCLUSIONS AND IMPLICATIONS

We provide the first evidence that, despite beneficial metabolic effects, fenretinide treatment may enhance the development of atherosclerosis.

HDL therapy today: from atherosclerosis, to stent compatibility to heart failure

Epidemiologically, high-density lipoprotein (HDL) cholesterol levels have been inversely associated to cardiovascular (CV) events, although a Mendelian Randomisation Study had failed to establish a clear causal role. Numerous atheroprotective mechanisms have been attributed to HDL, the main being the ability to promote cholesterol efflux from arterial walls; anti-inflammatory effects related to HDL ligands such as S1P (sphingosine-1-phosphate), resolvins and others have been recently identified. Experimental studies and early clinical investigations have indicated the potential of HDL to slow progression or induce regression of atherosclerosis. More recently, the availability of different HDL formulations, with different phospholipid moieties, has allowed to test other indications for HDL therapy. Positive reports have come from studies on coronary stent biocompatibility, where the use of HDL from different sources reduced arterial cell proliferation and thrombogenicity. The observation that low HDL-C levels may be associated with an enhanced risk of heart failure (HF) has also suggested that HDL therapy may be applied to this condition. HDL infusions or apoA-I gene transfer were able to reverse heart abnormalities, reduce diastolic resistance and improve cardiac metabolism. HDL therapy may be effective not only in atherosclerosis, but also in other conditions, of relevant impact on human health.Key messagesHigh-density lipoproteins have as a major activity that of removing excess cholesterol from tissues (particularly arteries).Knowledge on the activity of high-density lipoproteins on health have however significantly widened.HDL-therapy may help to improve stent biocompatibility and to reduce peripheral arterial resistance in heart failure.

Infusions of Large Synthetic HDL Containing Trimeric apoA-I Stabilize Atherosclerotic Plaques in Hypercholesterolemic Rabbits

BACKGROUND

Among strategies to reduce the remaining risk of cardiovascular disease, interest has focused on using infusions of synthetic high-density lipoprotein (sHDL).

METHODS

New Zealand rabbits underwent a perivascular injury at both carotids and were randomly allocated into 2 protocols: (1) a single-dose study, where rabbits were treated with a single infusion of sHDL containing a trimeric form of human apoA-I (TN-sHDL, 200 mg/kg) or with Placebo; (2) a multiple-dose study, where 4 groups of rabbits were treated 5 times with Placebo or TN-sHDL at different doses (8, 40, 100 mg/kg). Plaque changes were analysed in vivo by intravascular ultrasound. Blood was drawn from rabbits for biochemical analyses and cholesterol efflux capacity evaluation.

RESULTS

In both protocols, atheroma volume in the Placebo groups increased between the first and the second intravascular ultrasound evaluation. A stabilization or a slight regression was instead observed vs baseline in the TN-sHDL-treated groups (P < 0.005 vs Placebo after infusion). TN-sHDL treatment caused a sharp rise of plasma-free cholesterol levels and a significant increase of total cholesterol efflux capacity. Histologic analysis of carotid plaques showed a reduced macrophage accumulation in TN-sHDL-treated rabbits compared with Placebo (P < 0.05).

CONCLUSIONS

Our results demonstrate that acute and subacute treatments with TN-sHDL are effective in stabilizing atherosclerotic plaques in a rabbit model. This effect appears to be related to a reduced intraplaque accumulation of inflammatory cells. Besides recent failures in proving its efficacy, sHDL treatment remains a fascinating therapeutic option for the reduction of cardiovascular risk.

Topiramate protects apoE-deficient mice from kidney damage without affecting plasma lipids

Topiramate is an anticonvulsant drug also prescribed for migraine prophylaxis that acts through several mechanisms of action. Several studies indicate that topiramate induces weight loss and a moderate reduction of plasma lipids and glucose. Based on these favourable metabolic effects, aim of this study was to evaluate if topiramate could modulate atherosclerosis development and protect target organs of dysmetabolic conditions. Thirty apoE-deficient mice were divided into three groups and fed for 12 weeks a high fat diet (Control) or the same diet containing topiramate at 0.125% and 0.250%. Body weight, water and food intake were monitored throughout the study. Plasma lipids and glucose levels were measured and a glucose tolerance test was performed. Atherosclerosis development was evaluated in the whole aorta and at the aortic sinus. Histological analysis of liver, kidney and adipose tissue was performed. Topiramate did not affect weight gain and food intake. Glucose tolerance and plasma lipids were not changed and, in turn, atherosclerosis development was not different among groups. Topiramate did not modify liver and adipose tissue histology. Conversely, in the kidneys, the treatment reduced the occurrence of glomerular lipidosis by decreasing foam cells accumulation and reducing the expression of inflammatory markers. Blood urea nitrogen levels were also reduced by treatment. Our results indicate that topiramate does not affect atherosclerosis development, but preserves kidney structure and function. The study suggests that topiramate could be investigated in drug repurposing studies for the treatment of glomerular lipidosis.

Effects of Vegetable Proteins on Hypercholesterolemia and Gut Microbiota Modulation

Risk assessment tools, i.e., validated risk prediction algorithms, to estimate the patient's 10-year risk of developing cardiovascular disease (CVD) should be used to identify high-risk people for primary prevention. Current evidence confirms that appropriate monitoring and control of risk factors either reduces the likelihood of CVD or slows down its progression. It is thus crucial that all health professionals make appropriate use of all the available intervention strategies to control risk factors: from dietary improvement and adequate physical activity to the use of functional foods, food supplements, and drugs. The gut microbiota, which encompasses 1 × 1014 resident microorganisms, has been recently recognized as a contributing factor in the development of human disease. This review examines the effect of both some vegetable food components belong to the "protein food group" and the underexploited protein-rich hempseed on cholesterolemia and gut microbiota composition.

Intrapleural Administration of Interleukin-2 and Lak Cells in Locally Advanced Non-Small-Cell Lung Cancer. A Case Report

Aims and background

The systemic administration of recombinant interleukin-2 (rIL-2) and lymphokine-activated killer (LAK) cells is ineffective in non-small-cell lung cancer (NSCLC). However, there is some evidence that their intrapleural administration could be effective, since it increases the concentrations of the cytokine and the effector cells in the tumor area, thereby obtaining greater antitumor activity.

Study design

We report the case of a patient affected by a locally advanced lung adenocarcinoma with pleural effusion (T4 NO MO – stage 1Mb) treated with repetitive courses consisting of a priming continuous i.v. infusion (48 h) of rIL-2 (18 MIU/m2/day) intraplural administration of LAK cells (3 – 9 × 109/day), in a single daily bolus, for 3 consecutive days and concomitant administration of rlL-2 (1.8-7.2 × 106 IU/day), for 5 days.

Results

We observed early disappearance of neoplastic cells in the pleural effusion, progressive decrease until disappearance of the pleural effusion, cavitation of the primary lesion during the treatment, and its stabilization for 9 months until progression. Radiologic changes were accompanied by a marked eosinophilia (up to 50 × 109/L), and the intrapleural route of administration of rIL-2 induced a relevant increase in eosinophil count in peripheral blood. Immunologic changes in lymphocyte subpopulation phenotypes were also observed. The performance status of the patient improved, and she was still alive and eupnoic 25 months from the diagnosis and 23 months from the start of treatment.

Conclusions

This case suggests a therapeutic role for intrapleural rIL-2, and we believe that the relationship among intrapleural administration of rIL-2 and LAK cells, the development of peripheral eosinophilia, and clinical response should be further investigated.

Effect of Dietary Components from Antarctic Krill on Atherosclerosis in apoE-Deficient Mice

SCOPE

Antarctic krill is a great source of n-3 fatty acids and high-quality proteins. Aim of the study was to evaluate the effect of Antarctic krill components on plasma lipids and atherosclerosis development.

METHODS AND RESULTS

Sixty apoEKO mice were divided into four groups and fed Western diet (CONTROL) or Western-like diets, differing for protein or fat content. Specifically, casein or fat in CONTROL was partially replaced by krill proteins (PRO), krill oil (KRILL OIL), or both (KRILL OIL+PRO). In KRILL OIL+PRO and KRILL OIL, cholesterol levels were significantly lower than in CONTROL group. Atherosclerosis in aorta of PRO, KRILL OIL and KRILL OIL+PRO was lower than in CONTROL, whereas, at the aortic sinus, atherosclerosis reduction was only observed in KRILL OIL. Liver steatosis, commonly present in CONTROL and PRO animals, was sporadic in KRILL OIL+PRO and KRILL OIL mice. Krill oil containing diets affected the expression of genes involved in cholesterol metabolism, mainly HMG-CoA reductase. No reduced systemic inflammation was found in all groups.

CONCLUSION

Krill oil containing diets were able to reduce cholesterol levels, inhibit plaque development and prevent liver damage. Krill proteins also reduced atherosclerosis development through mechanisms not involving lipid metabolism.

Liver-specific deletion of the Plpp3 gene alters plasma lipid composition and worsens atherosclerosis in apoE-/- mice

The PLPP3 gene encodes for a ubiquitous enzyme that dephosphorylates several lipid substrates. Genome-wide association studies identified PLPP3 as a gene that plays a role in coronary artery disease susceptibility. The aim of the study was to investigate the effect of Plpp3 deletion on atherosclerosis development in mice. Because the constitutive deletion of Plpp3 in mice is lethal, conditional Plpp3 hepatocyte-specific null mice were generated by crossing floxed Plpp3 mice with animals expressing Cre recombinase under control of the albumin promoter. The mice were crossed onto the athero-prone apoE^-/- background to obtain Plpp3^f/fapoE^-/-Alb-Cre⁺ and Plpp3^f/fapoE^-/-Alb-Cre^- offspring, the latter of which were used as controls. The mice were fed chow or a Western diet for 32 or 12 weeks, respectively. On the Western diet, Alb-Cre⁺ mice developed more atherosclerosis than Alb-Cre^- mice, both at the aortic sinus and aorta. Lipidomic analysis showed that hepatic Plpp3 deletion significantly modified the levels of several plasma lipids involved in atherosclerosis, including lactosylceramides, lysophosphatidic acids, and lysophosphatidylinositols. In conclusion, Plpp3 ablation in mice worsened atherosclerosis development. Lipidomic analysis suggested that the hepatic Plpp3 deletion may promote atherosclerosis by increasing plasma levels of several low-abundant pro-atherogenic lipids, thus providing a molecular basis for the observed results.

L-homoarginine administration reduces neointimal hyperplasia in balloon-injured rat carotids

Supplementary Material to this article is available at www.thrombosis-online.com.

Nutraceuticals and Bioactive Components from Fish for Dyslipidemia and Cardiovascular Risk Reduction

Cardiovascular disease remains the most common health problem in developed countries, and residual risk after implementing all current therapies is still high. Permanent changes in lifestyle may be hard to achieve and people may not always be motivated enough to make the recommended modifications. Emerging research has explored the application of natural food-based strategies in disease management. In recent years, much focus has been placed on the beneficial effects of fish consumption. Many of the positive effects of fish consumption on dyslipidemia and heart diseases have been attributed to n-3 polyunsaturated fatty acids (n-3 PUFAs, i.e., EPA and DHA); however, fish is also an excellent source of protein and, recently, fish protein hydrolysates containing bioactive peptides have shown promising activities for the prevention/management of cardiovascular disease and associated health complications. The present review will focus on n-3 PUFAs and bioactive peptides effects on cardiovascular disease risk factors. Moreover, since considerable controversy exists regarding the association between n-3 PUFAs and major cardiovascular endpoints, we have also reviewed the main clinical trials supporting or not this association.

High-Density Lipoprotein-Targeted Therapy and Apolipoprotein A-I Mimetic Peptides

Numerous randomized clinical trials have established statins as the major standard therapy for atherosclerotic diseases because these molecules decrease the plasma level of low-density lipoprotein (LDL) cholesterol and moderately increase that of plasma high-density lipoprotein (HDL) cholesterol. The reverse cholesterol transport pathway, mediated by HDL particles, has a relevant antiatherogenic potential. An important approach to HDL-targeted therapy is optimization of the HDL-cholesterol level and enhanced removal of plasma cholesterol, together with the prevention and mitigation of inflammation related to atherosclerosis. Small-molecule inhibitors of cholesteryl ester transfer protein (CETP) increase the HDL-cholesterol level in subjects with normal or low HDL-cholesterol. However, CETP inhibitors do not seem to reduce the risk of atherosclerotic diseases. HDL therapies using reconstituted HDL, including apolipoprotein (Apo) A-I Milano, ApoA-I mimetics, or full-length ApoA-I, are dramatically effective in animal models. Of those, the ApoA-I-mimetic peptide called FAMP effectively removes cholesterol via the ABCA1 transporter and acts as an antiatherosclerotic agent by enhancing the biological functions of HDL without elevating the HDL-cholesterol level. Our review of the literature leads us to conclude that HDL-targeted therapies have significant atheroprotective potential and thus may effectively treat patients with cardiovascular diseases.

High-density lipoprotein deficiency in genetically modified mice deeply affects skin morphology: A structural and ultrastructural study

Cutaneous lipids, endogenously synthetized and transported by lipoproteins, play a pivotal role in maintaining skin barrier. An impairment of extracutaneous lipid trafficking leads to the development of xanthomas, mostly arising in hyperlipidemic patients, but also in subjects with high-density lipoprotein (HDL) deficiency. The aim of this work was to evaluate, in a genetically modified mouse model, lacking two protein components of HDL particles, apolipoprotein(apo)E and apoA-I, the effect of HDL deficiency on skin morphology. Control mice (C57BL/6), apoE deficient mice (EKO), apoA-I deficient mice (A-IKO) and apoA-I/apoE double knockout mice (A-IKO/EKO) were maintained on a low-fat/low-cholesterol diet up to 30 weeks of age. At sacrifice, skin biopsies were processed for light (LM) and transmission electron microscopy (TEM). Whereas the skin of EKO, A-IKO, and C57BL/6 mice was comparable, LM analysis in A-IKO/EKO mice showed an increase in dermal thickness and the presence of foam cells and T lymphocytes in reticular dermis. TEM analysis revealed the accumulation of cholesterol clefts in the papillary dermis and of cholesterol crystals within foam cells. In conclusion, A-IKO/EKO mice represent an experimental model for investigating the cutaneous phenotype of human HDL deficiency, thus mimicking a condition in which human xanthomatous lesions can develop.

Magnetic resonance imaging visualization of vulnerable atherosclerotic plaques at the brachiocephalic artery of apolipoprotein E knockout mice by the blood-pool contrast agent B22956/1

The aim of this study was to identify, by magnetic resonance imaging (MRI), the ability of the blood-pool contrast agent B22956/1 to detect atherosclerotic plaques developing at the brachiocephalic artery of apolipoprotein E knockout (apoE-KO) mice and to possibly identify vulnerable atherosclerotic lesions. After high-fat feeding for 8 or 12 weeks, MRIs of brachiocephalic arteries were acquired before and after B22956/1 administration; then vessels were removed and analyzed by histology. B22956/1 injection caused a rapid increase in plaque signal enhancement and plaque to muscle contrast values, which remained stable up to 70 minutes. A linear correlation between signal enhancement and macrophage content was found 10 minutes after B22956/1 injection (p < .01). Signal enhancement and plaque to muscle contrast values correlated with macrophage content 40 minutes after contrast agent administration (p < .01). Finally, 70 minutes after B22956/1 infusion, plaque to muscle contrast significantly correlated with the percentage of stenosis (p < .005). B22956/1 administration to high fat-fed apoE-KO mice resulted in a rapid enhancement of atherosclerotic plaques and in a great ability to rapidly visualize vulnerable plaques, characterized by a high macrophage content. These results suggest that B22956/1 could represent an interesting tool for the identification of atherosclerotic plaques potentially leading to acute cardiovascular events.