Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

BACKGROUND

Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies.

METHODS

For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia.

FINDINGS

Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified.

INTERPRETATION

Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life.

FUNDING

Pfizer, Amgen, Merck Sharp & Dohme, Sanofi-Aventis, Daiichi Sankyo, and Regeneron.

Stratification in Heterozygous Familial Hypercholesterolemia: Imaging, Biomarkers, and Genetic Testing

PURPOSE OF REVIEW

Heterozygous familial hypercholesterolemia (HeFH) is the most common monogenic autosomal dominant disorder. However, the condition is often underdiagnosed and undertreated. The objective of this review is to provide an update on the risk stratification in patients with HeFH, incorporating new cardiovascular imaging techniques, various biomarkers, and genetic studies.

RECENT FINDINGS

The diagnosis of HeFH places patients in a high cardiovascular risk category due to the increased incidence of premature atherosclerotic cardiovascular disease. However, the level of risk varies significantly among different individuals with HeFH. Achieving an optimal stratification of cardiovascular risk is crucial for establishing appropriate and accurate treatment and management strategies. Different new tools such as risk scores have emerged in recent years, aiding physicians in assessing the risk stratification for HeFH using imaging, biomarkers, and genetics. This review emphasizes that not all patients with HeFH face the same cardiovascular risk. By utilizing different assessment tools, we can identify those who require more intensive monitoring, follow-up, and treatment.

Remnant cholesterol levels are associated with severity and death in COVID-19 patients

Coronavirus disease-19 (COVID-19) patients with severe complications present comorbidities like cardiovascular-disease, hypertension and type-2 diabetes mellitus (DM), sharing metabolic alterations like insulin resistance (IR) and dyslipidemia. Our objective was to evaluate the association among different components of the lipid-lipoprotein profile, such as remnant lipoprotein (RLP)-cholesterol, in patients with COVID-19, and to analyze their associations with the severity of the disease and death. We studied 193 patients (68 (29-96) years; 49.7% male) hospitalized for COVID-19 and 200 controls (46 (18-79) years; 52.5% male). Lipoprotein profile, glucose and procalcitonin were assessed. Patients presented higher glucose, TG, TG/HDL-cholesterol and RLP-cholesterol levels, but lower total, LDL, HDL and no-HDL-cholesterol levels (p < 0.001). When a binary logistic regression was performed, age, non-HDL-cholesterol, and RLP-cholesterol were associated with death (p = 0.005). As the COVID-19 condition worsened, according to procalcitonin tertiles, a decrease in all the cholesterol fractions (p < 0.03) was observed with no differences in TG, while levels of RLP-cholesterol and TG/HDL-cholesterol increased (p < 0.001). Lower levels of all the cholesterol fractions were related with the presence and severity of COVID-19, except for RLP-cholesterol levels and TG/HDL-cholesterol index. These alterations indicate a lipid metabolic disorder, characteristic of IR states in COVID-19 patients. RLP-cholesterol levels predicted severity and death in these patients.

Epicardial Adipose Tissue Ceramides Are Related to Lipoprotein Lipase Activity in Coronary Artery Disease: Unfolding a Missing Link

BACKGROUND

Epicardial adipose tissue (EAT) contributes to coronary artery disease (CAD). EAT presents a specific lipidomic signature, showing increased ceramides and other proinflammatory lipids content. Besides, LPL (lipoprotein lipase) activity in EAT would contribute to its expansion, supplying fatty acids to the tissue. Our aim was to evaluate the relations between LPL activity, regulators of LPL, and ceramides in EAT from CAD patients.

METHODS

We studied patients undergoing coronary bypass graft (CAD, n=25) and patients without CAD (no CAD, n=14). EAT and subcutaneous AT (SAT) were obtained, tissue LPL activity and its regulator's expression (ANGPTL4, GPIHBP1 [glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1], and PPARγ [peroxisomal proliferator-activated receptor γ]) were assessed. Tissue lipidomes were evaluated by UHPLC-MS, in positive and negative ionization modes.

RESULTS

LPL activity was higher in EAT from CAD (P<0.001), and in EAT than SAT in both groups (P<0.001). ANGPTL4 levels were lower, GPIHBP1 and PPARγ levels were higher in EAT from CAD (P<0.001). In both groups, EAT exhibited more ceramide (P=0.01), directly associated with LPL activity, being the strongest association with Cer18:1/24:1 (P<0.001). EAT Cer18:1/16:0 to Cer18:1/24:0 and Cer18:1/24:1 to 18:1/24:0 ratios were higher in CAD (P=0.03; P<0.001, respectively), the latter directly associated with LPL activity (r=0.63, P<0.001) GPIHBP1 levels (r=0.68, P<0.001), and inversely to EAT ANGPTL4 expression (r=-0.49, P=0.03). Pairwise partial correlation network showed associations among bioactive lipids and LPL and its regulators (P<0.001 in all cases).

CONCLUSIONS

The association between LPL activity, total ceramide, and the atherogenic ceramide ratios highlights the importance of the enzyme and these bioactive lipids contributing to the different metabolic profile of EAT in CAD.

Global perspective of familial hypercholesterolaemia: a cross-sectional study from the EAS Familial Hypercholesterolaemia Studies Collaboration (FHSC)

BACKGROUND

The European Atherosclerosis Society Familial Hypercholesterolaemia Studies Collaboration (FHSC) global registry provides a platform for the global surveillance of familial hypercholesterolaemia through harmonisation and pooling of multinational data. In this study, we aimed to characterise the adult population with heterozygous familial hypercholesterolaemia and described how it is detected and managed globally.

METHODS

Using FHSC global registry data, we did a cross-sectional assessment of adults (aged 18 years or older) with a clinical or genetic diagnosis of probable or definite heterozygous familial hypercholesterolaemia at the time they were entered into the registries. Data were assessed overall and by WHO regions, sex, and index versus non-index cases.

FINDINGS

Of the 61 612 individuals in the registry, 42 167 adults (21 999 [53·6%] women) from 56 countries were included in the study. Of these, 31 798 (75·4%) were diagnosed with the Dutch Lipid Clinic Network criteria, and 35 490 (84·2%) were from the WHO region of Europe. Median age of participants at entry in the registry was 46·2 years (IQR 34·3-58·0); median age at diagnosis of familial hypercholesterolaemia was 44·4 years (32·5-56·5), with 40·2% of participants younger than 40 years when diagnosed. Prevalence of cardiovascular risk factors increased progressively with age and varied by WHO region. Prevalence of coronary disease was 17·4% (2·1% for stroke and 5·2% for peripheral artery disease), increasing with concentrations of untreated LDL cholesterol, and was about two times lower in women than in men. Among patients receiving lipid-lowering medications, 16 803 (81·1%) were receiving statins and 3691 (21·2%) were on combination therapy, with greater use of more potent lipid-lowering medication in men than in women. Median LDL cholesterol was 5·43 mmol/L (IQR 4·32-6·72) among patients not taking lipid-lowering medications and 4·23 mmol/L (3·20-5·66) among those taking them. Among patients taking lipid-lowering medications, 2·7% had LDL cholesterol lower than 1·8 mmol/L; the use of combination therapy, particularly with three drugs and with proprotein convertase subtilisin-kexin type 9 inhibitors, was associated with a higher proportion and greater odds of having LDL cholesterol lower than 1·8 mmol/L. Compared with index cases, patients who were non-index cases were younger, with lower LDL cholesterol and lower prevalence of cardiovascular risk factors and cardiovascular diseases (all p<0·001).

INTERPRETATION

Familial hypercholesterolaemia is diagnosed late. Guideline-recommended LDL cholesterol concentrations are infrequently achieved with single-drug therapy. Cardiovascular risk factors and presence of coronary disease were lower among non-index cases, who were diagnosed earlier. Earlier detection and greater use of combination therapies are required to reduce the global burden of familial hypercholesterolaemia.

FUNDING

Pfizer, Amgen, Merck Sharp & Dohme, Sanofi-Aventis, Daiichi Sankyo, and Regeneron.

Use and persistence of lipid-lowering therapy in patients with severe hypercholesterolemia: A prospective study

INTRODUCTION

Statins are the first line of treatment in patients with severe hypercholesterolemia (SH). However, despite the knowledge regarding its effectiveness and security for preventing cardiovascular diseases, treatment is a major challenge.

MATERIAL AND METHODS

A prospective observational study was conducted by telephone survey to determine cardiovascular risk factors, annual monitoring, statins use and persistence and new-onset cardiovascular events (CVE) after 5 years in patients with SH including in a program for detection of familial hypercholesterolemia.

RESULTS

115 participants were analysed, the median age was 56 ±10 being 74% females. 63.4% of women and 43% of men had been correctly controlled in the last year. Patients on lipid lowering drugs stratified by sex was 38.8% in women and 26.7% in men, however, only 22 participants (31.8%) were persistence with statins since 2015.Overall, 48% of the patients presented a CVE and 3.4% died. Multivariate analysis did not reveal predictors for CVE.

CONCLUSIONS

In our population with SH we found a high risk to present a CVE and a dramatic low use and persistence with the treatment.

Reducing the Clinical and Public Health Burden of Familial Hypercholesterolemia: A Global Call to Action

Importance

Familial hypercholesterolemia (FH) is an underdiagnosed and undertreated genetic disorder that leads to premature morbidity and mortality due to atherosclerotic cardiovascular disease. Familial hypercholesterolemia affects 1 in 200 to 250 people around the world of every race and ethnicity. The lack of general awareness of FH among the public and medical community has resulted in only 10% of the FH population being diagnosed and adequately treated. The World Health Organization recognized FH as a public health priority in 1998 during a consultation meeting in Geneva, Switzerland. The World Health Organization report highlighted 11 recommendations to address FH worldwide, from diagnosis and treatment to family screening and education. Research since the 1998 report has increased understanding and awareness of FH, particularly in specialty areas, such as cardiology and lipidology. However, in the past 20 years, there has been little progress in implementing the 11 recommendations to prevent premature atherosclerotic cardiovascular disease in an entire generation of families with FH.

Observations

In 2018, the Familial Hypercholesterolemia Foundation and the World Heart Federation convened the international FH community to update the 11 recommendations. Two meetings were held: one at the 2018 FH Foundation Global Summit and the other during the 2018 World Congress of Cardiology and Cardiovascular Health. Each meeting served as a platform for the FH community to examine the original recommendations, assess the gaps, and provide commentary on the revised recommendations. The Global Call to Action on Familial Hypercholesterolemia thus represents individuals with FH, advocacy leaders, scientific experts, policy makers, and the original authors of the 1998 World Health Organization report. Attendees from 40 countries brought perspectives on FH from low-, middle-, and high-income regions. Tables listing country-specific government support for FH care, existing country-specific and international FH scientific statements and guidelines, country-specific and international FH registries, and known FH advocacy organizations around the world were created.

Conclusions and Relevance

By adopting the 9 updated public policy recommendations created for this document, covering awareness; advocacy; screening, testing, and diagnosis; treatment; family-based care; registries; research; and cost and value, individual countries have the opportunity to prevent atherosclerotic heart disease in their citizens carrying a gene associated with FH and, likely, all those with severe hypercholesterolemia as well.

Phenotype of definite familial hypercholesterolemia with negative genetic study in Argentina

Objective

Familial hypercholesterolemia (FH) is a monogenic disease, associated with variants in the LDLR, APOB and PCSK9 genes. The initial diagnosis is based on clinical criteria like the DLCN criteria. A score > 8 points qualifies the patient as "definite" for FH diagnosis. The detection of the presence of a variant in these genes allows carrying out familial cascade screening and better characterizes the patient in terms of prognosis and treatment.

Methods

In the context of the FH detection program in Argentina (Da Vinci Study) 246 hypercholesterolemic patients were evaluated, 21 with DLCN score > 8 (definite diagnosis).These patients were studied with next generation sequencing to detect genetic variants, with an extended panel of 23 genes; also they were adding the large rearrangements analysis and a polygenic score of 10 SNP (single nucleotide polymorphism) related to the increase in LDL-c.

Results

Of the 21 patients, 10 had variants in LDLR, 1 in APOB with APOE, 1 in LIPC plus elevated polygenic score, and 2 patients showed one deletion and one duplication in LDLR, the later with a variation in LIPA. It is highlighted that 6 of the 21 patients with a score > 8 did not show any genetic alteration.

Conclusions

We can conclude that 28% of the patients with definite clinical diagnosis of FH did not show genetic alteration. The possible explanations for this result would be the presence of mutations in new genes, confusing effects of the environment over the genes, the gene-gene interactions, and finally the impossibility of detecting variants with the current available methods.

Phenotypical, Clinical, and Molecular Aspects of Adults and Children With Homozygous Familial Hypercholesterolemia in Iberoamerica

OBJECTIVE

Characterize homozygous familial hypercholesterolemia (HoFH) individuals from Iberoamerica. Approach and Results: In a cross-sectional retrospective evaluation 134 individuals with a HoFH phenotype, 71 adults (age 39.3±15.8 years, 38.0% males), and 63 children (age 8.8±4.0 years, 50.8% males) were studied. Genetic characterization was available in 129 (96%). The majority (91%) were true homozygotes (true HoFH, n=79, 43.0% children, 46.8% males) or compound heterozygotes (compound heterozygous familial hypercholesterolemia, n=39, 51.3% children, 46.2% males) with putative pathogenic variants in the LDLR. True HoFH due to LDLR variants had higher total (P=0.015) and LDL (low-density lipoprotein)-cholesterol (P=0.008) compared with compound heterozygous familial hypercholesterolemia. Children with true HoFH (n=34) tended to be diagnosed earlier (P=0.051) and had a greater frequency of xanthomas (P=0.016) than those with compound heterozygous familial hypercholesterolemia (n=20). Previous major cardiovascular events were present in 25 (48%) of 52 children (missing information in 2 cases), and in 43 (67%) of 64 adults with LDLR variants. Children who are true HoFH had higher frequency of major cardiovascular events (P=0.02), coronary heart (P=0.013), and aortic/supra-aortic valve diseases (P=0.022) than compound heterozygous familial hypercholesterolemia. In adults, no differences were observed in major cardiovascular events according to type of LDLR variant. From 118 subjects with LDLR variants, 76 (64%) had 2 likely pathogenic or pathogenic variants. In 89 subjects with 2 LDLR variants, those with at least one null allele were younger (P=0.003) and had a greater frequency of major cardiovascular events (P=0.038) occurring at an earlier age (P=0.001).

CONCLUSIONS

There was a high frequency of cardiovascular disease even in children. Phenotype and cardiovascular complications were heterogeneous and associated with the type of molecular defect.

Fenotipo de hipercolesterolemia familiar definitivo con estudio genético negativo en Argentina

Objective

Familial hypercholesterolemia (FH) is a monogenic disease, associated with variants in the LDLR, APOB and PCSK9 genes. The initial diagnosis is based on clinical criteria like the DLCN criteria. A score > 8 points qualifies the patient as "definite" for FH diagnosis. The detection of the presence of a variant in these genes allows carrying out familial cascade screening and better characterizes the patient in terms of prognosis and treatment.

Methods

In the context of the FH detection program in Argentina (Da Vinci Study) 246 hypercholesterolemic patients were evaluated, 21 with DLCN score > 8 (definite diagnosis).These patients were studied with next generation sequencing to detect genetic variants, with an extended panel of 23 genes; also they were adding the large rearrangements analysis and a polygenic score of 10 SNP (single nucleotide polymorphism) related to the increase in LDL-c.

Results

Of the 21 patients, 10 had variants in LDLR, 1 in APOB with APOE, 1 in LIPC plus elevated polygenic score, and 2 patients showed one deletion and one duplication in LDLR, the later with a variation in LIPA. It is highlighted that 6 of the 21 patients with a score > 8 did not show any genetic alteration.

Conclusions

We can conclude that 28% of the patients with definite clinical diagnosis of FH did not show genetic alteration. The possible explanations for this result would be the presence of mutations in new genes, confusing effects of the environment over the genes, the gene-gene interactions, and finally the impossibility of detecting variants with the current available methods.

Triglycerides and residual risk

PURPOSE OF REVIEW

To review the recent evidence from observational/genetic/interventional studies addressing triglycerides and residual cardiovascular risk (CVRisk).

RECENT FINDINGS

Large population-based and secondary prevention studies consistently show an association of higher triglycerides with increased CVRisk. This is compounded by genetic studies demonstrating an independent relationship between triglyceride raising or lowering genetic variants affecting triglyceride-rich lipoproteins (TRL) metabolism and CVRisk. Mendelian randomization analysis suggests the benefit of genetic lowering of triglycerides and LDL-cholesterol is similar per unit change in apolipoprotein-B. Among cholesterol-lowering trials, more intensive statin therapy produced greater CVRisk reductions in patients with higher TRL-cholesterol or triglycerides; proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition led to similar triglycerides reduction but greater non-HDL-C or apolipoprotein-B reductions than fibrates or fish oils. Regarding n-3 fatty acids, A Study of Cardiovascular Events in Diabetes (ASCEND) and Vitamin D and Omega-3 Trial (VITAL) primary prevention trials with eicosapentaenoic acid (EPA) and docosahexaenoic acid failed to demonstrate cardiovascular benefits, Conversely, Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial (REDUCE-IT) using high-dose icosapent-ethyl (purified EPA) in primary (diabetes) and secondary prevention with hypertriglyceridemia showed significant cardiovascular events reductions (greater than expected by the observed triglycerides or apolipoprotein-B reductions, suggesting potential benefits through non-lipid pathways).

SUMMARY

Evidence suggests higher triglycerides are a marker of CVRisk and may help identify patients who benefit from intensification of therapy. Moreover, genetic studies support a causal link between TRL/triglycerides and cardiovascular disease. Treatment with high-dose EPA may be of benefit in high-risk patients with hypertriglyceridemia to reduce CVRisk.

Untargeted Lipidomics Reveals a Specific Enrichment in Plasmalogens in Epicardial Adipose Tissue and a Specific Signature in Coronary Artery Disease

OBJECTIVE

Epicardial adipose tissue (EAT) is an active endocrine organ that could contribute to the pathophysiology of coronary artery disease (CAD) through the paracrine release of proatherogenic mediators. Numerous works have analyzed the inflammatory signature of EAT, but scarce informations on its lipidome are available. Our objective was first to study the differences between EAT and subcutaneous adipose tissue (SAT) lipidomes and second to identify the specific untargeted lipidomic signatures of EAT and SAT in CAD. Approach and Results: Subcutaneous and EAT untargeted lipidomic analysis was performed in 25 patients with CAD and 14 patients without CAD and compared with paired plasma lipidomic analysis of isolated VLDL (very low-density lipoprotein) and HDL (high-density lipoprotein). Lipidomics was performed on a C18 column hyphenated to a Q-Exactive plus mass spectrometer, using both positive and negative ionization mode. EAT and SAT had independent lipidomic profile, with 95 lipid species differentially expressed and phosphatidylethanolamine 18:1p/22:6 twenty-fold more expressed in EAT compared with SAT false discovery rate =3×10^-4). Patients with CAD exhibited more ceramides (P=0.01), diglycerides (P=0.004; saturated and nonsaturated), monoglycerides (P=0.013) in their EAT than patients without CAD. Conversely, they had lesser unsaturated TG (triglycerides; P=0.02). No difference was observed in the 295 lipid species found in SAT between patients with and without CAD. Fifty-one lipid species were found in common between EAT and plasma lipoproteins. TG 18:0/18:0/18:1 was found positively correlated (r=0.45, P=0.019) in EAT and HDL and in EAT and VLDL (r=0.46, P=0.02).

CONCLUSIONS

CAD is associated with specific lipidomic signature of EAT, unlike SAT. Plasma lipoprotein lipidome only partially reflected EAT lipidome.

Fetal and postnatal zinc restriction: Sex differences in metabolic alterations in adult rats

OBJECTIVE

Intrauterine and postnatal micronutrient malnutrition may program metabolic diseases in adulthood. We examined whether moderate zinc restriction in male and female rats throughout fetal life, lactation, or postweaning growth induces alterations in liver, adipose tissue, and intermediate metabolism.

METHODS

Female Wistar rats were fed low-zinc or control zinc diets from pregnancy to offspring weaning. After weaning, male and female offspring were fed either a low-zinc or a control zinc diet. At 74 d of life, oral glucose tolerance tests were performed and serum metabolic profiles were evaluated. Systolic blood pressure and oxidative stress and morphology of liver and retroperitoneal adipose tissue were evaluated in 81 d old offspring.

RESULTS

Zinc restriction during prenatal and postnatal life induced an increase in systolic blood pressure, hyperglycemia, hypertriglyceridemia, higher serum glucose levels at 180 min after glucose overload, and greater insulin resistance indexes in male rats. Hepatic histologic studies revealed no morphologic alterations, but an increase in lipid peroxidation and catalase activity were identified in zinc-deficient male rats. Adipose tissue from zinc-deficient male rats had adipocyte hypertrophy, an increase in lipid peroxidation, and a reduction in catalase and glutathione peroxidase activity. Adequate dietary zinc content during postweaning growth reversed basal hyperglycemia, hypertriglyceridemia, insulin resistance indexes, hepatic oxidative stress, and adipocyte hypertrophy. Female rats were less sensitive to the metabolic effects of zinc restriction.

CONCLUSIONS

This study strengthens the importance of a balanced intake of zinc during growth to ensure adequate lipid and carbohydrate metabolism in adult life.

Vitamin D is Related to Markers of Vulnerable Plaque in Acute Myocardial Infarction

BACKGROUND

Vitamin D is a fat soluble vitamin involved in calcium and bone metabolism; recently its deficiency has been related to cardiovascular disease. In cardiac tissue, vitamin D suppresses metalloproteinases (MMPs) expression, enzymes directly associated with vulnerable plaque.

OBJECTIVE

To investigate whether the association between vitamin D and leptin is related to markers of vulnerable plaque, such as MMPs in patients with acute myocardial infarction.

METHODS

We studied 66 male patients with acute myocardial infarction, undergoing primary angioplasty. Blood samples were obtained at admission and 24hs after the surgery. Leptin and vitamin D concentrations in serum and MMP-2 and -9 activities in plasma were determined.

RESULTS

MMP-2 activity was increased in Vitamin D deficient/insufficient patients at admission (p=0.04) and 24 hs later (p=0.05). In a linear regression model, vitamin D explained 24% of the variance of MMP-2 activity (F=2.839 p=0.04). At admission, vitamin D correlated with serum leptin (r=-0.302 p=0.033), and explained 39.5% of its variation (F=4.432 p=0.003).

CONCLUSION

In the studied population, vitamin D was inversely related to MMP-2 and leptin which are involved in coronary artery disease and acute myocardial infarction. The decrease in this hormone levels would be associated with a worse metabolic profile in acute coronary syndrome patients.

Metalloproteinases in non-alcoholic fatty liver disease and their behavior in liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a clinical entity of high prevalence in the world characterized by fatty infiltration of liver tissue in the absence of alcohol consumption. The natural history of the disease develops in successive phases reflected in different histological stages, with 10-20% of patients developing liver cirrhosis and fibrosis. Fibrosis is a basic connective tissue lesion defined by the increase of the fibrillary extracellular matrix (ECM) components in a tissue or organ. Matrix metalloproteinases (MMPs) constitute a family of endopeptidases, which are involved in ECM and basement membranes components degradation. Fibrogenic process is characterized by altered ECM composition, associated with modifications in MMPs behavior. The active cross-talk between adipose tissue and liver can be altered in pathologies associated to insulin resistance (IR), such as NAFLD. The role of adipokines on MMPs behavior in the liver could be partly responsible of liver damage during IR. The aim of this revision is to describe the behavior of MMPs in NAFLD and its role in the associated fibrosis.

Metalloproteinase 2 and 9 Activity Increase in Epicardial Adipose Tissue of Patients with Coronary Artery Disease

BACKGROUND

Epicardial adipose tissue (EAT) is a visceral adipose tissue (AT) surrounding and infiltrating myocardium and coronary arteries. Increased EAT may represent a chronic inflammatory injury and a link with coronary artery disease (CAD). Metalloproteinases (MMPs) are involved in expansion of AT.

OBJECTIVE

To evaluate MMP-2 and -9 behaviour in EAT from CAD patients.

METHODS

In EAT and subcutaneous AT (SAT) from patients undergoing coronary artery bypass graft (CABG, n=26) or valve replacement (No CABG, n=18), MMP-2 and -9 activity and localization, inflammatory cells and vascular endothelial growth factor (VEGF) levels were determined.

RESULTS

In EAT from CABG, MMP-2 and -9 activity was increased compared with No CABG (p=0.041 and p=0.027, respectively) and compared with SAT (p=0.005 and p=0.048, respectively). In CABG patients EAT showed higher infiltration of macrophages and T lymphocytes than SAT (p=0.01 and p=0.002, respectively). In No CABG patients no sign of cellular retention was observed in EAT or SAT. Vascular density was higher in EAT from CABG than No CABG (p=0.015) and it was directly correlated with MMP-2 (p=0.006) and MMP-9 (p=0.02). VEGF levels in EAT were directly associated with MMP-2 (p=0.016).

CONCLUSION

In EAT from CABG patients the increase of MMP-2 and -9 activity and the presence of inflammatory cells would be partially responsible for extracellular matrix (ECM) remodeling and major vascular density necessary for EAT expansion. Improved knowledge of EAT behaviour may allow to identify new therapeutic targets for the treatment of CAD.

Nonalcoholic fatty liver disease associated with metabolic syndrome: Influence of liver fibrosis stages on characteristics of very low-density lipoproteins

BACKGROUND

We evaluated possible changes in VLDLcharacteristics, and metabolic related factors, in MetS-associated NAFLD and accompanying liver fibrosis.

METHODS

We studied 36 MetS patients with biopsy-proven NAFLD (MetS+NAFLD) and 24 MetS without ultrasound NAFLD evidence. Further, MetS+NAFLD was sub-divided according to fibrosis stage into, non-to-moderate (F0-F2, n=27) and severe (F3-F4, n=9) fibrosis. We measured: lipid profile, VLDL composition and size (size exclusion-HPLC), CETP and lipoprotein lipase (LPL) activities and adiponectin. Additionally, in MetS+NAFLD type IV collagen 7S domain was measured.

RESULTS

MetS+NAFLD showed increased VLDL-mass, VLDL particle number, VLDL-triglyceride% and large VLDL-% (p<0.04). CETP activity tended to increase in MetS+NAFLD (p=0.058), while LPL activity was unchanged. Moreover, in MetS+NAFLD, adiponectin was decreased (p<0.001), and negatively correlated with VLDL-mass and VLDL particle number (p<0.05), independently of insulin-resistance. Within MetS+NAFLD group, despite greater insulin-resistance, patients with severe fibrosis showed lower plasma triglycerides, VLDL-mass, VLDL-triglyceride%, large VLDL-% and CETP activity (p<0.05), while type IV collagen was increased (p=0.009) and inversely correlated with large VLDL-% (p=0.045).

CONCLUSIONS

In MetS, NAFLD is associated with larger and triglyceride over-enriched circulating VLDLs, of greater atherogenicity. However, when NAFLD progresses to severe fibrosis, circulating VLDL features apparently improved, probably due to early alterations in hepatic synthetic function.

Supplementation with n-3, n-6, n-9 fatty acids in an insulin-resistance animal model: does it improve VLDL quality?

Could supplementation with n-3, n-6 and n-9 fatty acids prevent atherogenic alterations of VLDL produced in insulin-resistance?

Atherogenic Lipoproteins in Subclinical Hypothyroidism and Their Relationship with Hepatic Lipase Activity: Response to Replacement Treatment with Levothyroxine

BACKGROUND

Qualitative lipoprotein changes, such as an increase in fasting remnants, are reported in subclinical hypothyroidism (SCH). It was hypothesized that such changes are due to reduced hepatic lipase (HL) activity in SCH: HL is an enzyme regulated by thyroid hormones, and is involved in the degradation of triglyceride (TG)-rich remnants. This study aimed to quantify remnant-like lipoproteins (RLP), small dense LDL (sdLDL), and HL activity in women with SCH, and to assess these parameters after levothyroxine replacement therapy.

METHODS

This was an observational cross-sectional study with a subsequent longitudinal follow-up. Findings in women with thyrotropin levels >4.5 mIU/L (SH group) were compared with age- and body mass index (BMI)-matched euthyroid women (control group). In addition, a subgroup analysis was undertaken in SCH women who chose to receive levothyroxine treatment (0.9 μg/kg/day) for 6 months. RLP was quantified by measuring cholesterol (RLP-C) and triglycerides (RLP-TG) after immunoaffinity chromatography, and sdLDL by automated standardized methods; HL activity was measured in post-heparin plasma.

RESULTS

The SCH group included 37 women; 29 women were included in the control group. In addition, 22 women with SCH were included in the subgroup analysis (levothyroxine treatment). Significantly higher RLP values were observed in the SCH group than in the control group: RLP-C (median [range], mg/dL): 20.3 (5.8-66.8) versus 10.2 (2.7-36.3), p = 0.005; RLP-TG (mg/dL): 26.3 (3.2-123.3) versus 12.1 (2.5-61.6), p = 0.033. HL activity (mean ± standard deviation [SD], μmol free fatty acid/mL post-heparin plasma.h)-9.83 ± 4.25 versus 9.92 ± 5.20, p = 0.707-and sdLDL levels (mg/dL)-23.1 ± 10.7 versus 22.6 ± 8.4, p = 0.83-were similar. After levothyroxine, RLP-C decreased-21.5 (5.8-66.8) versus 17.2 (4.1-45.6), p = 0.023-and HL increased-9.75 ± 4.04 versus 11.86 ± 4.58, p = 0.012-in the subgroup of SCH women. No changes in sdLDL were observed.

CONCLUSIONS

Women with SCH have higher RLP levels than matched controls do, but their RLP-C levels decrease significantly following levothyroxine therapy. Furthermore, HL activity also increases after levothyroxine therapy and can be interpreted as a possible explanation for the decrease in RLP-C.

Glycaemic changes in patients with chronic kidney disease

In Argentina, there have been no studies aimed at establishing the prevalence of dysglycaemia (impaired fasting glucose [IFG], impaired glucose tolerance [IGT] and diabetes mellitus [DM]) in patients with chronic kidney disease (CKD). Our group decided to conduct an observational study to evaluate the frequency with oral glucose tolerance test (OGTT) in CKD patients with no previous data for dysglycaemia in their medical records. OGTT was performed in 254 patients (60.62% male) with stage 3, 4 and 5 CKD under conservative treatment, haemodialysis or transplantation. Results for DM were found in 10 patients according to fasting glucose alone (3.94%; 95% CI: 1.35-6.53%), 11 patients with exclusively the second hour criterion (4.33%; 95% CI: 1.63-7.03%), 15 with both criteria (5.91%; 95% CI: 2.81-9.00%) and 36 patients with at least one criteria (14.17%; 95% CI: 9.69-18.66%). In a multivariate analysis, DM was associated with waist circumference (OR=1.033 per cm; 95% CI, 1.005 to 1.062; P=.019) and with conservative treatment vs. replacement therapy (OR=0.41; 95% CI: 0.19-0.92; P=.028). IGT was evident in 24.6% and 20.3 on conservative vs. replacement therapy, with no statistically significant difference. IFG (ADA criteria) was 19.75 vs. 9.24% in conservative vs. replacement therapy, with a statistically significant difference. OGTT is suggested for all CKD patients since it is able to detect the full range of unknown dysglycaemias, which avoids underdiagnoses and favours performing treatments to prevent progression in DM risk groups (IFG and/or IGT). It also aids in the selection of the most appropriate medication for transplantation or treatment initiation in new cases of undiagnosed DM to decrease morbidity and mortality.

Matrix metalloproteinases and psychosocial factors in acute coronary syndrome patients

Psychosocial factors have been linked to cardiovascular diseases independently of traditional risk factors. The impact of psychosocial factors on plaque destabilizing factors, such as matrix metalloproteinases (MMPs) has been proposed although scarcely studied.

OBJECTIVE

To evaluate the relationships between hostility, perceived stress and social support with MMPs activity in patients after an Acute Myocardial Infarction (AMI).

METHODS

Blood samples were obtained from 76 patients on admission, post-angioplasty, 24h, 7 days and 3 months after AMI. Hostility, perceived stress and social support were evaluated by validated questionnaires.

RESULTS

Social support was positively correlated with patientś ejection fraction (r=0.453, p=0.009). Patients with higher infarct size presented increased MMP-2 activity at admission (p=0.04). Patients with one diseased vessel had more social support than those with three diseased vessels (p=0.05). The highest values of MMP-2 and MMP-9 activity were observed at the acute event, decreasing, with the lowest activity at 3 months post-AMI (p<0.001). Only in patients with low social support, hostility correlated with MMP-2 activity, from AMI onset (r=0.645, p=0.013), to 7 days post AMI (r=0.557, p=0.038). Hostility explained up to 28% of the variance in MMP-2 activity (R(2)=0.28, p=0.005). Finally, in patients with high hostility, MMP-9 was positively correlated with IL-1β (r=0.468, p=0.02).

CONCLUSIONS

This study adds weight to the idea that two psychosocial factors, namely hostility and social support, acting jointly, may affect MMP-2 activity. Moreover, in hostile patients, there is a link between IL-1β and MMP-9. These findings support the role of psychosocial factors in plaque destabilization and in the inflammatory process in AMI.

Circulating and adipose tissue matrix metalloproteinases in cardiometabolic risk environments: pathophysiological aspects

Matrix metalloproteinases (MMPs) play an important role during physiological tissue remodeling in embryonic development and angiogenesis, as well as in pathophysiological conditions such as obesity and development and vulnerability of atherosclerotic plaque. Moreover, MMP circulating levels have emerged as potential biomarkers of cardiovascular disease. MMP expression and activity are regulated by different factors such as insulin resistance and obesity. Expanded fat tissue has been demonstrated to be an active organ, where MMPs also exert a role in adipogenesis, angiogenesis, and proliferation of extracellular matrix (ECM). However, the lack of association between adipose tissue and plasma levels of some MMPs, specifically MMP-2 and MMP-9, suggests that this tissue is not a major contributor to circulating gelatinases. MMPs are also co-expressed or co-repressed in response to inflammatory adipocytokines, like adiponectin and leptin. Adiponectin may also play a protective role in plaque rupture through selectively increasing the tissue inhibitor of metalloproteinase (TIMP) expression. Leptin induces the expression of MMP-2 activators as well as the expression of MMP-2, MMP-9, and TIMP-1 in different human cells. Furthermore, sex hormones also participate in MMP regulation. In postmenopausal women, hormone replacement therapy produces an increase in MMP activity, leading to a breakdown in ECM homeostasis and accelerated progression of vascular pathologies. Besides, in men, an inverse relationship between testosterone levels and MMP-2 activity has been described. It is still necessary to go forward in the study of MMPs in different metabolic situations to corroborate their role as vulnerable plaque biomarkers.

Increased cholesterol efflux capacity in metabolic syndrome: Relation with qualitative alterations in HDL and LCAT

BACKGROUND

Metabolic syndrome (MetS) is associated with changes in HDL levels, composition and sub-fraction profile. Whether these alterations affect HDL anti-atherogenic function, specifically measured as its capacity to perform cholesterol efflux, is not yet clearly known.

OBJECTIVE

To evaluate the relation between serum cholesterol efflux capacity and the changes in HDL composition and sub-fraction profile in MetS.

METHODS

In 35 non-treated MetS patients and 15 healthy controls, HDL mediated cholesterol efflux was measured as the ability of apoB-depleted serum to accept cholesterol from cholesterol-loaded BHK cells expressing either ABCA1 or ABCG1. Additionally we determined: lipid profile, HDL sub-fractions (NMR) and LCAT mass (ELISA). Isolated HDL (δ:1.063-1.210 g/mL) was chemically characterized. Pre-β1-HDL was determined by 2D-electrophoresis in a sub-group of MetS and controls (n = 6 each).

RESULTS

Surprisingly, MetS patients presented higher ABCA1 mediated cholesterol efflux (10.4 ± 1.8 vs. 8.7 ± 0.3%; p = 0.0001), without differences in ABCG1 efflux. In MetS, HDL showed reduction in particle size and number (p < 0.02) and lower large/small HDL ratio (p = 0.05), as well as triglyceride enrichment (p = 0.0001). Pre-β1-HDL was increased in MetS (p = 0.048) and correlated with ABCA1-cholesterol efflux (r = 0.64; p = 0.042). LCAT mass showed a tendency to reduction in MetS (p = 0.08), and inversely correlated with ABCA1-cholesterol efflux (r = -0.51; p = 0.001), independently of obesity and insulin-resistance (β = -0.40, p = 0.034).

CONCLUSION

This is the first description of ABCA1 mediated cholesterol efflux in MetS. Regardless the reduced HDL-cholesterol, in vitro cholesterol efflux capacity by ABCA1 was enhanced, linked to increased pre-β1-HDL and slightly reduced in LCAT mass that would probably reflect a delay in reverse cholesterol transport occurring in MetS.

Monounsaturated fatty acids-rich diets in hypercholesterolemic-growing rats

The effects of replacing dietary saturated fat by different monounsaturated fatty acid (ω-9MUFA) sources on serum lipids, body fat and bone in growing hypercholesterolemic rats were studied. Rats received one of the six different diets: AIN-93G (control, C); extra virgin olive oil (OO) + C; high-oleic sunflower oil (HOSO) + C or atherogenic diet (AT) for 8 weeks; the remaining two groups received AT for 3 weeks and then, the saturated fat was replaced by an oil mixture of soybean oil added with OO or HOSO for 5 weeks. Rats consuming MUFA-rich diets showed the highest body fat, hepatic index and epididymal, intestinal and perirenal fat, and triglycerides. T-chol and non-HDL-chol were increased in HOSO rats but decreased in OO rats. Bone mineral content and density were higher in both OO and HOSO groups than in AT rats. This study casts caution to the generalization of the benefits of MUFA for the treatment of hypercholesterolemia.

Overproduction of altered VLDL in an insulin-resistance rat model: Influence of SREBP-1c and PPAR-α

BACKGROUND

In insulin-resistance, VLDL presents alterations that increase its atherogenic potential. The mechanism by which insulin-resistance promotes the production of altered VLDL is still not completely understood. The aim of this study was to evaluate the relationship between the expression of sterol regulatory element binding protein 1c (SREBP-1c) and of peroxisome proliferator-activated receptor-α (PPAR-α), with the features of composition and size of VLDL in an insulin-resistance rat model induced by a sucrose rich diet (SRD).

METHODS

The study was conducted on 12 male Wistar rats (180g) receiving SRD (12 weeks) and 12 controls. Lipid profile, free fatty acids, glucose, and insulin were measured. Lipid content in liver and visceral fat were assessed. Isolated VLDL (d<1.006g/ml) was characterized by its chemical composition and size by HPLC. The respective hepatic expression of SREBP-1c and PPAR-α was determined (Western blot).

RESULTS

As expected, SRD had elevated triglycerides (TG), free fatty acids and insulin levels, and decreased HDL-cholesterol (p<0.05), together with augmented hepatic and visceral fat (p<0.05). SRD showed higher VLDL total mass - with increased TG content - and predominance of large VLDL (p<0.05). SRD showed an increase in SREBP-1c (precursor and mature forms) and decreased PPAR-α expression (p<0.045). SREBP-1c forms were positively associated with VLDL total mass (p<0.04), VLDL-TG% (p<0.019), and large VLDL% (p<0.002). On the other hand, PPAR-α correlated negatively with VLDL total mass (p=0.05), VLDL-TG% (p=0.005), and large VLDL% (p=0.002).

CONCLUSIONS

Insulin-resistance, by coordinated activation of SREBP-1c and reduction of PPAR-α, could promote the secretion of larger and TG over-enriched VLDL particles, with greater atherogenic capacity.

Adiponectin predicts MMP-2 activity independently of obesity

BACKGROUND

Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9, have been identified in atherosclerotic plaques and have been directly associated with plaque remodelling and vulnerability. Cardiovascular disease (CVD) is related to insulin resistance (IR) and obesity, characterized by changes in plasma levels of inflammatory markers, such as adiponectin and C-reactive protein (CRP). Our aim was to evaluate the impact of both proteins on MMP-2 and MMP-9 behaviour in individuals with IR.

MATERIALS AND METHODS

Plasma MMP-2 and MMP-9 activity, adiponectin and hs-CRP concentration and lipoprotein profile were determined in 52 patients with metabolic syndrome (MS) and 27 controls.

RESULTS

Patients with MS presented significantly higher MMP-2 activity than controls: 0·95 ± 0·12 vs. 0·77 ± 0·15 relative units (RU) (P < 0·001), while MMP-9 activity was not detectable. MMP-2 activity decreased across quartiles of adiponectin, being significantly reduced in individuals with the highest levels of adiponectin in compared with the lowest levels (0·75 ± 0·17 vs. 0·93 ± 0·09 RU, P < 0·005). This difference persisted significant after adjusting by obesity markers. MMP-2 activity was significantly increased in individuals with the highest levels (G3) compared with those with the lowest levels (G1) of hs-CRP (0·94 ± 0·12 vs. 0·86 ± 0·12, P = 0·041) CONCLUSION: In this study, we observed that adiponectin levels predicted MMP-2 plasma activity independently of obesity. This finding suggests that the inflammatory process, associated with the highest CVD risk, would be involved in MMPs vascular production.

Effect of insulin-resistance on circulating and adipose tissue MMP-2 and MMP-9 activity in rats fed a sucrose-rich diet

BACKGROUND AND AIM

Adipose tissue produces different metalloproteinases (MMPs), involved in adipogenesis and angiogenesis. Different studies have shown that in obesity the behavior of different MMPs may be altered. However there are scarce data about the effect of insulin-resistance (IR) on MMP-2 and MMP-9 activity in adipose tissue. Our aim was to determine whether sucrose induced IR modifies MMP-2 and MMP-9 behavior in expanded visceral adipose tissue and the contribution of this tissue to circulating activity of these gelatinases.

METHODS AND RESULTS

Male Wistar rats were fed with standard diet (Control) or standard diet plus 30% sucrose in the drinking water throughout 12 weeks (SRD). In epididymal adipose tissue vascular density, size and adipocyte density, PPARγ expression and MMP-2 and -9 were measured. Adipose tissue from SRD presented higher adipocyte size (6.32 ± 8.71 vs 4.33 ± 2.17 × 10(3) μm(2), p = 0.001) lower adipocyte density (164 (130-173) vs 190 (170-225) number/mm(2), p = 0.046) and lower vascular density (16.2 (12.8-23.5) vs 28.1 (22.3-46.5) blood vessels/mm(2), p = 0.002) than Control. MMP-2 and MMP-9 activity was decreased in SRD (1.93 ± 0.7 vs 3.92 ± 0.9 relative units, p = 0.048 and 1.80 ± 0.8 vs 5.13 ± 1.7 relative units, p = 0.004 respectively) in accordance with lower protein expression (0.35 ± 0.20 vs 2.71 ± 0.48 relative units, p = 0.004 and 1.12 ± 0.21 vs 1.52 ± 0.05 relative units, p = 0.036 respectively). There were no differences in PPARγ expression between groups.

CONCLUSION

Insulin resistance induced by SRD decreases MMP-2 and MMP-9 activity in adipose tissue which would not represent an important source for circulating MMP-2 and -9. In this state of IR, PPARγ would not be involved in the negative regulation of adipose tissue gelatinases.

[A history and review of cholesterol ester transfer protein inhibitors and their contribution to the understanding of the physiology and pathophysiology of high density lipoprotein]

There is irrefutable evidence that statins reduce the risk of cardiovascular events in a magnitude proportional to the intensity of the decrease in cholesterol transport by the low density lipoproteins. Despite this great advance there is still a residual risk of cardiovascular events. For this reason, an increase in the levels of high density lipoprotein is considered in order to boost the main action of this lipoprotein, which is reverse cholesterol transport. Distinct classes of evidence (epidemiological, genetic, and pathophysiological) show that the inhibition and/or modulation of cholesterol ester transfer protein increases plasma high density lipoprotein-cholesterol levels. The main reason for presenting this review is to look at the physiology of cholesterol ester transfer protein, its interrelationship with high density lipoproteins, and to give an update on the development of different cholesterol ester transfer protein inhibitor/modulator molecules.

Role of SN1 lipases on plasma lipids in metabolic syndrome and obesity

OBJECTIVE

To assess the phospholipase activity of endothelial (EL) and hepatic lipase (HL) in postheparin plasma of subjects with metabolic syndrome (MS)/obesity and their relationship with atherogenic and antiatherogenic lipoproteins. Additionally, to evaluate lipoprotein lipase (LPL) and HL activity as triglyceride (TG)-hydrolyses to complete the analyses of SN1 lipolytic enzymes in the same patient.

APPROACH AND RESULTS

Plasma EL, HL, and LPL activities were evaluated in 59 patients with MS and 36 controls. A trend toward higher EL activity was observed in MS. EL activity was increased in obese compared with normal weight group (P=0.009) and was negatively associated with high-density lipoprotein-cholesterol (P=0.014 and P=0.005) and apolipoprotein A-I (P=0.045 and P=0.001) in control and MS group, respectively. HL activity, as TG-hydrolase, was increased in MS (P=0.025) as well as in obese group (P=0.017); directly correlated with low-density lipoprotein-cholesterol (P=0.005) and apolipoprotein B (P=0.003) and negatively with high-density lipoprotein-cholesterol (P=0.021) in control group. LPL was decreased in MS (P<0.001) as well as in overweight and obese compared with normal weight group (P=0.015 and P=0.004, respectively); inversely correlated %TG-very low-density lipoproteins (P=0.04) and TG/apolipoprotein B index (P=0.013) in control group. These associations were not found in MS.

CONCLUSIONS

We describe for the first time EL and HL activity as phospholipases in MS/obesity, being both responsible for high-density lipoprotein catabolism. Our results elucidate part of the remaining controversies about SN1 lipases activity in MS and different grades of obesity. The impact of insulin resistance on the activity of the 3 enzymes determines the lipoprotein alterations observed in these states.

Relationship between cortisol, life events and metabolic syndrome in men

Psychological factors and stressful life events (LE) are considered to play a role in the onset of the metabolic syndrome (MS). We tested the association between LE and cortisol, a marker of chronic stress, with the risk of developing MS and their interaction. From a total number of 2906 men who completed a screening for the early detection of prostate cancer, 149 healthy men (mean ± SD age, 58.6 ± 7.7 years) were included in this study. Participants were assessed by the Holmes and Rahe questionnaire about their experience of LE during the previous 1-5 years. MS was diagnosed according to National Cholesterol Education Program-Adult Treatment Panel III (ATP-III) and International Diabetes Federation (IDF) criteria. Serum cortisol was measured at 08:00-09:00 h. Participants with MS (IDF criteria) reported significantly more past LE (p = 0.009) and greater summed weight of LE (p = 0.049) than those without MS. Furthermore, LE interacted with cortisol in relation to MS: in men with increased serum cortisol levels ( ≥ 13.7 μg/dl), number of LE significantly predicted MS-status (relative risk (RR) = 1.16, p = 0.03), whereas in men with low cortisol, LE were unrelated to MS (p = 0.52). We conclude that LE were significantly more prevalent in men with the MS than without the MS, according to IDF criteria, independent of the effects of age and body mass index, especially in men with increased serum cortisol levels.

Endothelial Lipase Activity Predicts High-Density Lipoprotein Catabolism in Hemodialysis

Objective—

A novel phospholipase assay was used to measure for the first time the behavior of endothelial and hepatic phospholipase activities in postheparin human plasma of hemodialyzed patients and its relationship with atherogenic and antiatherogenic lipoprotein levels.

Methods and Results—

Endothelial and hepatic phospholipase activity was assessed in a total SN1-specific phospholipase assay, using (1-decanoylthio-1-deoxy-2-decanoyl-sn-glycero-3-phosphoryl) ethylene glycol as the substrate. Hemodialyzed patients presented lower values of total and hepatic phospholipase activity than controls: 4.4 (1.9–9.0) versus 7.5 (3.6–18.0) and 2.6 (0.7–6.2) versus 6.6 (1.3–15.2) μmol of fatty acid released per milliliter of postheparin plasma per hour, respectively ( P <0.001); however, endothelial lipase (EL) phospholipase activity was increased in patients: 1.7 (0.8–3.0) versus 1.1 (0.1–2.7) μmol of fatty acid released per milliliter of postheparin plasma per hour ( P =0.008). EL was negatively associated with high-density lipoprotein (HDL)-cholesterol ( r =–0.427; P =0.001), and apolipoprotein A-I levels, total phospholipase, and hepatic lipase activity were directly associated with low-density lipoprotein-cholesterol and apolipoprotein B. The association of EL and HDL-cholesterol remained significant when adjusting for waist circumference (β=–0.26; P =0.05), and the effect of hepatic lipase on low-density lipoprotein-cholesterol continued after adjusting for age (β=0.46; P = 0.001).

Conclusion—

Our results support the hypothesis that EL is the predominant enzyme responsible for lipolytic catabolism of HDLs in hemodialyzed patients and resolve the apparent paradox observed between low hepatic lipase activity and decreased HDL-cholesterol levels observed in these patients. In addition, the ability to assess total hepatic lipase and EL phospholipase activity in plasma will increase our knowledge of the mechanisms involved in controlling HDL levels and cardiovascular risk in hemodialyzed patients, as well as other populations with low levels of HDL-cholesterol.