Acute hypertriglyceridaemia in humans increases the triglyceride content and decreases the anti-inflammatory capacity of high density lipoproteins

Higher triglyceride levels are associated with the higher prevalence of layered plaques in non-culprit coronary plaques

High triglyceride (TG) levels have been recognized as a risk factor for cardiovascular events in patients with coronary artery disease (CAD). This study aimed to clarify the association between TG levels and characteristics of non-culprit coronary plaques in patients with CAD. A total of 531 consecutive patients with stable CAD who underwent percutaneous coronary intervention for culprit lesions and optical coherence tomography (OCT) assessment of non-culprit plaques in the culprit vessel were included in this study. The morphology of the non-culprit plaques assessed by OCT imaging were compared between the higher TG (TG ≥ 150 mg/dL, n = 197) and lower TG (TG < 150 mg/dL, n = 334) groups. The prevalence of layered plaques (40.1 vs. 27.5%, p = 0.004) was significantly higher in the higher TG group than in the lower TG group, although the prevalence of other plaque components was comparable between the two groups. High TG levels were an independent factor for the presence of layered plaques (odds ratio 1.761, 95% confidence interval 1.213-2.558, p = 0.003) whereas high low-density lipoprotein cholesterol levels (≥ 140 mg/dL) and low eicosapentaenoic acid/arachidonic acid ratios (< 0.4) were independently associated with a higher prevalence of thin-cap fibroatheroma and macrophages. Higher TG levels were associated with a higher prevalence of layered plaques in non-culprit plaques among patients with stable CAD. These results may partly explain the effect of TG on the progression of coronary plaques and the increased incidence of recurrent events in patients with CAD.

A stronger association of depression with rheumatoid arthritis in presence of obesity and hypertriglyceridemia

Background

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by chronic and systemic inflammation. Recent research underscores the role of chronic inflammation in multiple common RA comorbidities such as depression, obesity, and cardiovascular diseases (CVDs), suggesting a potential overlap of the pathogenic mechanisms for RA. However, it is not well understood how the coexistence of these comorbid conditions impacts the risk of RA and whether any such association relates to body's inflammatory state.

Methods

We used data from the 2007-2010 United States National Health and Nutrition Examination Survey (NHANES) database and compared RA prevalence between subsamples with the presence of any two conditions among depression, obesity, and hypertriglyceridemia (HTG). Each subsample was further divided into three categories based on the serum level of the inflammatory marker C-reactive protein (CRP) and analyzed for statistically significant differences using three-way χ2 tests of independence.

Results

The study was conducted on 4,136 patients who fulfilled the inclusion criteria (representing 163,540,241 individuals after adjustment for sampling weights). Rates of depression, obesity, and HTG were found to be significantly higher (P < 0.001) among the subjects with RA compared with the control population with no arthritis. The presence of depression along with obesity or HTG showed a noticeably higher RA prevalence but such an association was not observed for the combination of obesity and HTG. The synergistic effect of HTG with depression was found to be most prominent at a medium CRP level (1-3 mg/L), while for obesity, the effect was observed across all CRP levels examined. These findings were further confirmed by the three-way χ2 test for independence.

Conclusions

The presence of obesity or HTG in subjects suffering from depression might pose an increased risk of RA. Inflammatory mechanisms potentially play an important underlying role as suggested by the strong dependency of the association to CRP level. Identification of synergistic associations between RA risk conditions could provide useful information to predict the development and progress of RA.

Integrated omics approach for the identification of HDL structure-function relationships in PCSK9-related familial hypercholesterolemia

BACKGROUND

The role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in dyslipidemia may go beyond its immediate effects on low-density lipoprotein receptor (LDL-R) activity.

OBJECTIVE

This study aimed to assess PCSK9-derived alterations of high-density lipoprotein (HDL) physiology, which bear a potential to contribute to cardiovascular risk profile.

METHODS

HDL was isolated from 33 patients with familial autosomal dominant hypercholesterolemia (FH), including those carrying PCSK9 gain-of-function (GOF) genetic variants (FH-PCSK9, n = 11), together with two groups of dyslipidemic patients employed as controls and carrying genetic variants in the LDL-R not treated (ntFH-LDLR, n = 11) and treated (tFH-LDLR, n = 11) with statins, and 11 normolipidemic controls. Biological evaluations paralleled by proteomic, lipidomic and glycomic analyses were applied to characterize functional and compositional properties of HDL.

RESULTS

Multiple deficiencies in the HDL function were identified in the FH-PCSK9 group relative to dyslipidemic FH-LDLR patients and normolipidemic controls, which involved reduced antioxidative, antiapoptotic, anti-thrombotic and anti-inflammatory activities. By contrast, cellular cholesterol efflux capacity of HDL was unchanged. In addition, multiple alterations of the proteomic, lipidomic and glycomic composition of HDL were found in the FH-PCSK9 group. Remarkably, HDLs from FH-PCSK9 patients were systematically enriched in several lysophospholipids as well as in A2G2S2 (GP13) glycan and apolipoprotein A-IV. Based on network analysis of functional and compositional data, a novel mosaic structure-function model of HDL biology involving FH was developed.

CONCLUSION

Several metrics of anti-atherogenic HDL functionality are altered in FH-PCSK9 patients paralleled by distinct compositional alterations. These data provide a first-ever overview of the impact of GOF PCSK9 genetic variants on structure-function relationships in HDL.

High-Density Lipoprotein in Metabolic Disorders and Beyond: An Exciting New World Full of Challenges and Opportunities

High-density lipoprotein (HDL) is an enigmatic member of the plasma lipid and lipoprotein transport system, best known for its ability to promote the reverse cholesterol efflux and the unloading of excess cholesterol from peripheral tissues. More recently, data in experimental mice and humans suggest that HDL may play important novel roles in other physiological processes associated with various metabolic disorders. Important parameters in the HDL functions are its apolipoprotein and lipid content, further reinforcing the principle that HDL structure defines its functionality. Thus, based on current evidence, low levels of HDL-cholesterol (HDL-C) or dysfunctional HDL particles contribute to the development of metabolic diseases such as morbid obesity, type 2 diabetes mellitus, and nonalcoholic fatty liver disease. Interestingly, low levels of HDL-C and dysfunctional HDL particles are observed in patients with multiple myeloma and other types of cancer. Therefore, adjusting HDL-C levels within the optimal range and improving HDL particle functionality is expected to benefit such pathological conditions. The failure of previous clinical trials testing various HDL-C-raising pharmaceuticals does not preclude a significant role for HDL in the treatment of atherosclerosis and related metabolic disorders. Those trials were designed on the principle of "the more the better", ignoring the U-shape relationship between HDL-C levels and morbidity and mortality. Thus, many of these pharmaceuticals should be retested in appropriately designed clinical trials. Novel gene-editing-based pharmaceuticals aiming at altering the apolipoprotein composition of HDL are expected to revolutionize the treatment strategies, improving the functionality of dysfunctional HDL.

Effect of Pemafibrate on Hemorheology in Patients with Hypertriglyceridemia and Aggravated Blood Fluidity Associated with Type 2 Diabetes or Metabolic Syndrome

Persistent high serum triglyceride (TG) and free fatty acid (FFA) levels, which are common in metabolic syndrome and type 2 diabetes, are risk factors for cardiovascular events because of exacerbated hemorheology. To explore the effects of pemafibrate, a selective peroxisome proliferator-activated receptor alpha modulator, on hemorheology, we performed a single-center, nonrandomized, controlled study in patients with type 2 diabetes (HbA1c 6-10%) or metabolic syndrome, with fasting TG levels of ≥ 150 mg/dL and a whole blood transit time of > 45 s on a microarray channel flow analyzer (MCFAN). Patients were divided into a study group, receiving 0.2 mg/day of pemafibrate (n = 50) for 16 weeks, and a non-pemafibrate control group (n = 46). Blood samples were drawn 8 and 16 weeks after entry to the study to evaluate whole blood transit time as a hemorheological parameter, leukocyte activity by MCFAN, and serum FFA levels. No serious adverse events were observed in either of the groups. After 16 weeks, the pemafibrate group showed a 38.6% reduction in triglycerides and a 50.7% reduction in remnant lipoproteins. Pemafibrate treatment did not significantly improve whole blood rheology or leukocyte activity in patients with type 2 diabetes mellitus or metabolic syndrome complicated by hypertriglyceridemia and exacerbated hemorheology.

Hypertriglyceridemia and Atherosclerotic Carotid Artery Stenosis

Both fasting and non-fasting hypertriglyceridemia have emerged as residual risk factors for atherosclerotic disease. However, it is unclear whether hypertriglyceridemia increases the risks of the progression of carotid artery stenosis. Statins are well known to prevent carotid plaque progression and improve carotid plaque instability. In addition, statin therapy is also known to reduce cerebrovascular events in patients with carotid artery stenosis and to improve clinical outcomes in patients undergoing revascularization procedures. On the other hand, there have been no randomized controlled trials showing that the combination of non-statin lipid-lowering drugs with statins has additional beneficial effects over statin monotherapy to prevent cerebrovascular events and stenosis progression in patients with carotid artery stenosis. In this article, the authors demonstrate the mechanisms of atherosclerosis formation associated with hypertriglyceridemia and the potential role of lipid-lowering drugs on carotid artery stenosis. The authors also review the articles reporting the relationships between hypertriglyceridemia and carotid artery stenosis.

Normal HDL Cholesterol Efflux and Anti-Inflammatory Capacities in Type 2 Diabetes Despite Lipidomic Abnormalities

OBJECTIVE

To assess whether, in type 2 diabetes (T2D) patients, lipidomic abnormalities in high-density lipoprotein (HDL) are associated with impaired cholesterol efflux capacity and anti-inflammatory effect, 2 pro-atherogenic abnormalities.

DESIGN AND METHODS

This is a secondary analysis of the Lira-NAFLD study, including 20 T2D patients at T0 and 25 control subjects. Using liquid chromatography/tandem mass spectrometry, we quantified 110 species of the main HDL phospholipids and sphingolipids. Cholesterol efflux capacity was measured on THP-1 macrophages. The anti-inflammatory effect of HDL was measured as their ability to inhibit the tumor necrosis factor α (TNFα)-induced expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1) on human vascular endothelial cells (HUVECs).

RESULTS

The cholesterol-to-triglyceride ratio was decreased in HDL from T2D patients compared with controls (-46%, P = 0.00008). As expressed relative to apolipoprotein AI, the amounts of phosphatidylcholines, sphingomyelins, and sphingosine-1-phosphate were similar in HDL from T2D patients and controls. Phosphatidylethanolamine-based plasmalogens and ceramides (Cer) were, respectively, 27% (P = 0.038) and 24% (P = 0.053) lower in HDL from T2D patients than in HDL from controls, whereas phosphatidylethanolamines were 41% higher (P = 0.026). Cholesterol efflux capacity of apoB-depleted plasma was similar in T2D patients and controls (36.2 ± 4.3 vs 35.5 ± 2.8%, P = 0.59). The ability of HDL to inhibit the TNFα-induced expression of both VCAM-1 and ICAM-1 at the surface of HUVECs was similar in T2D patients and controls (-70.6 ± 16.5 vs -63.5 ± 18.7%, P = 0.14; and -62.1 ± 13.2 vs -54.7 ± 17.7%, P = 0.16, respectively).

CONCLUSION

Despite lipidomic abnormalities, the cholesterol efflux and anti-inflammatory capacities of HDL are preserved in T2D patients.

Impact of triglyceride levels on plaque characteristics in patients with coronary artery disease

BACKGROUND

High triglyceride (TG) levels have been demonstrated to be a risk factor for coronary artery disease. This study aimed to clarify the impact of TG levels on the characteristics of coronary plaques.

METHODS

A total of 850 consecutive patients who underwent optical coherence tomography (OCT) imaging of the culprit lesion were included. The morphologies of culprit plaques were compared between the higher TG group (nonfasting TG levels ≥150 mg/dL, n = 337) and the lower TG group (nonfasting TG <150 mg/dL, n = 513).

RESULTS

The prevalence of lipid-rich plaques (43% vs. 33%, p = 0.005), thin-cap fibroatheromas (TCFAs) (24% vs. 17%, p = 0.015) and macrophages (40% vs. 31%, p = 0.006) was significantly higher in the higher TG group than in the lower TG group. In addition to a high low-density lipoprotein cholesterol (LDL-C) level (≥140 mg/dL), high TGs (≥150 mg/dL) were identified as an independent factor for the presence of TCFAs (odds ratio 1.465, 95% confidence interval 1.004-2.137, p = 0.048). Among patients with lower LDL-C levels (<100 mg/dL), the prevalence of macrophages (38% vs. 26%, p = 0.007) and layered plaques (48% vs. 38%, p = 0.019) was significantly higher in the higher TG group than in the lower TG group.

CONCLUSIONS

Higher TG levels were associated with a higher prevalence of TCFAs in culprit coronary lesions. The prevalence of macrophages and layered plaques was more frequently observed in patients with higher TGs than those with lower TGs among patients with LDL-C < 100 mg/dL.

Breakfast partly restores the anti-inflammatory function of high-density lipoproteins from patients with type 2 diabetes mellitus

Background and aims

High-density lipoproteins (HDL) of patients with type 2 diabetes mellitus (T2DM) have impaired anti-inflammatory activities. The anti-inflammatory activity of HDL has been determined ex vivo after isolation by different methods from blood mostly obtained after overnight fasting. We first determined the effect of the HDL isolation method, and subsequently the effect of food intake on the anti-inflammatory function of HDL from T2DM patients.

Methods

Blood was collected from healthy controls and T2DM patients after an overnight fast, and from T2DM patients 3 h after breakfast (n = 17 each). HDL was isolated by a two-step density gradient ultracentrifugation in iodixanol (HDL_DGUC2), by sequential salt density flotation (HDL_SEQ) or by PEG precipitation (HDL_PEG). The anti-inflammatory function of HDL was determined by the reduction of the TNFα-induced expression of VCAM-1 in human coronary artery endothelial cells (HCAEC) and retinal endothelial cells (REC).

Results

HDL isolated by the three different methods from healthy controls inhibited TNFα-induced VCAM-1 expression in HCAEC. With apoA-I at 0.7 μM, HDL_DGUC2 and HDL_SEQ were similarly effective (16% versus 14% reduction; n = 3; p > 0.05) but less effective than HDL_PEG (28%, p < 0.05). Since ultracentrifugation removes most of the unbound plasma proteins, we used HDL_DGUC2 for further experiments. With apoA-I at 3.2 μM, HDL from fasting healthy controls and T2DM patients reduced TNFα-induced VCAM-1 expression in HCAEC by 58 ± 13% and 51 ± 20%, respectively (p = 0.35), and in REC by 42 ± 13% and 25 ± 18%, respectively (p < 0.05). Compared to preprandial HDL, postprandial HDL from T2DM patients reduced VCAM-1 expression by 56 ± 16% (paired test: p < 0.001) in HCAEC and by 34 ± 13% (paired test: p < 0.05) in REC.

Conclusions

The ex vivo anti-inflammatory activity of HDL is affected by the HDL isolation method. Two-step ultracentrifugation in an iodixanol gradient is a suitable method for HDL isolation when testing HDL anti-inflammatory function. The anti-inflammatory activity of HDL from overnight fasted T2DM patients is significantly impaired in REC but not in HCAEC. The anti-inflammatory function of HDL is partly restored by food intake.

Omega-3 Fatty Acids and Coronary Artery Disease: More Questions Than Answers

Studies show that patients with elevated triglycerides and well-controlled LDL levels under statin therapy still have a significant residual risk of cardiovascular (CV) events. Despite many attempts to reduce triglycerides with different hypolipidemic drugs, no therapeutic option has given satisfactory results so far. The initial enthusiasm that omega-3 fatty acids can effectively reduce triglycerides and CV risk was replaced with skepticism when the first large clinical trials failed to show any benefit in primary or secondary prevention. However, the latest studies succeeded in showing a positive effect of omega-3 fatty acids on CV outcome in patients with hypertriglyceridemia. The largest benefit was reported in secondary but not primary prevention. Interestingly, the reduction in triglycerides in some of these studies was disproportionately low to the relatively high CV risk reduction, which could indicate some other effects of omega-3 fatty acids that go well beyond hypotriglyceridemic action. This includes blood pressure reduction, antithrombotic effect, improvement of inflammatory status, endothelial function, and insulin resistance. Investigations also reported a significant and positive influence of omega-3 fatty acids on the composition and stabilization of coronary atherosclerotic plaques in patients with and without previous CV events. In addition to insufficiently known mechanisms of action and conflicting results about the effectiveness of omega-3 fatty acids, the safety problems, which include increased prevalence of atrial fibrillation and hemorrhage, were also reported. The aim of this clinical review was to summarize the current knowledge regarding the use of omega-3 fatty acids in CV patients, particularly those with coronary artery disease, and to present an overview of key clinical trial data.

Three two-site apoA-I immunoassays using phage expressed detector antibodies - Preliminary clinical evaluation with cardiac patients

High density lipoproteins (HDL) are a heterogenous group of subpopulations differing in protein/lipid composition and in their anti-atherogenic function. There is a lack of specific and robust assays which can target the functionality of HDL with respect to atherosclerosis. With recently generated CAD HDL targeted, single chain recombinant antibodies (scFvs) we set out to design and optimize apo A-I tests to compare it with conventional HDL-C and apo A-I analyses for diagnosis and risk assessment of coronary artery disease (CAD) and its outcome. Three highly sensitive two-site apo A-I assays: 022-454, 109-121 and 110-525 were optimized. A preliminary clinical evaluation of these assays, after proper sample dilution procedure, was performed using samples derived from 195 chest pain patients (myocardial infarction (MI), n = 86 and non-MI, n = 109), collected at the time of admission and at discharge from hospital (hospital stay ≤ 24 h). The clinical performance of the assays was compared with apo A-I measured with polyclonal anti-apo A-I antibody using conventional ELISA. Apo A-I data was in addition compared with HDL-C concentration of the samples. The concentration of apo A-I was significantly lower in MI patients than in non-MI individuals with assay 022-454 (admission and discharge samples, P < 0.0001 and = 0.004); assay 109-121 (admission and discharge samples, P = 0.04 and 0.0009), and, ELISA based apo A-I test (admission and discharge samples, P = 0.008 and < 0.0001). HDL-C (admission and discharge samples, P = 0.002 and P = 0.01) was also significantly lower in MI patients. In Kaplan- Meier analysis, two-site assay 109-121 assay predicted mortality from admission samples at 1.5 yrs (whole cohort, P = 0.01 and in MI patients, P = 0.05) and at 6 months (whole cohort, P = 0.04). Assay 110-525 predicted mortality at 1.5 yrs from admission samples of non-MI patients (P = 0.01) and at 6 months from whole discharge sample cohort (P = 0.04). Polyclonal anti-apo A-I based conventional assay predicted mortality at 1.5 yrs from admission samples of whole cohort (P = 0.03). Two-site apo A-I assay 022-454 and HDL-C provided no capability of predicting mortality in the whole cohort or any sub-group. In conclusion, two of the tested recombinant apo A-I antibody combinations (sc 109-121 and sc 110-525) display promising outcome to improve diagnosis and prediction of future cardiac events in cardiac patients over polyclonal apo A-I ELISA and HDL-C assays. The noted differences, while interesting, are preliminary and need however to be verified in extensive cohorts of pathological cardiac conditions and healthy controls.

NAFLD is related to Post-prandial Triglyceride-enrichment of HDL Particles in Association with Endothelial and HDL Dysfunction

NAFLD is closely related with the metabolic syndrome (MetS) and increased risk of cardiovascular disease. Liver fat associates with post-prandial hypertriglyceridemia, potentially contributing to triglyceride-enrichment of high-density lipoproteins (HDL-TG), and subsequent HDL dysfunction. We assessed liver fat by MR spectroscopy, and its association with HDL physiochemical properties, and endothelial function, measured as flow-mediated dilation (FMD), before and following three consecutive meals, in 36 men with type 2 diabetes mellitus (T2DM), with the MetS, and controls. Plasma triglycerides increased significantly following the meals (P < .001). Fasting HDL-TG was highest in T2DM, relative to MetS and controls (P = .002), and increased post-prandially in all groups (P < .001). HDL function was negatively associated with HDL-TG following three meals (r = -.32, P<.05). Liver fat associated with HDL-TG after three meals (r = .65, P < .001). HDL-TG was independently associated with FMD following three consecutive meals (r = -.477, P = .003). We conclude liver fat is associated with post-prandial HDL-TG enrichment which was closely related with endothelial and HDL dysfunction.

Cardioprotective Properties of HDL: Structural and Functional Considerations

BACKGROUND

As Mendelian Randomization (MR) studies showed no effect of variants altering HDL-cholesterol (HDL-C) levels concerning Cardiovascular Disease (CVD) and novel therapeutic interventions aiming to raise HDL-C resulted to futility, the usefulness of HDL-C is unclear.

OBJECTIVE

As the role of HDL-C is currently doubtful, it is suggested that the atheroprotective functions of HDLs can be attributed to the number of HDL particles, and their characteristics including their lipid and protein components. Scientific interest has focused on HDL function and on the causes of rendering HDL particles dysfunctional, whereas the relevance of HDL subclasses with CVD remains controversial.

METHODS

The present review discusses changes in quality as much as in quantity of HDL in pathological conditions and the connection between HDL particle concentration and cardiovascular disease and mortality. Emphasis is given to the recently available data concerning the cholesterol efflux capacity and the parameters that determine HDL functionality, as well as to recent investigations concerning the associations of HDL subclasses with cardiovascular mortality.

RESULTS

MR studies or pharmacological interventions targeting HDL-C are not in favor of the hypothesis of HDL-C levels and the relationship with CVD. The search of biomarkers that relate with HDL functionality is needed. Similarly, HDL particle size and number exhibit controversial data in the context of CVD and further studies are needed.

CONCLUSION

There is no room for the old concept of HDL as a silver bullet,as HDL-C cannot be considered a robust marker and does not reflect the importance of HDL particle size and number. Elucidation of the complex HDL system, as well as the finding of biomarkers, will allow the development of any HDL-targeted therapy.

Triglycerides and Cardiovascular Outcomes-Can We REDUCE-IT ?

The causal linkage between triglycerides and coronary artery disease has been controversial. Most of the trials hitherto have shown marginal or no beneficial effects of reduction of triglycerides (with fibrates) on top of low-density lipoprotein (LDL) reduction. But a significant residual cardiovascular risk remains even after use of high dose of statins. Omega-3 fatty acids have been shown to reduce triglyceride levels and some old trials have shown the benefits of fish oils in reducing cardiovascular events. However, barring a few trials most of the large trials of omega-3 fatty acids are negative. Recently, few large trials have been conducted to see the effects of high dose omega-3 fatty acids on cardiovascular outcomes and some of them have shown promising results on top of LDL reduction.

Triglycerides and Cardiovascular Outcomes-Can We REDUCE-IT ?

The causal linkage between triglycerides and coronary artery disease has been controversial. Most of the trials hitherto have shown marginal or no beneficial effects of reduction of triglycerides (with fibrates) on top of low-density lipoprotein (LDL) reduction. But a significant residual cardiovascular risk remains even after use of high dose of statins. Omega-3 fatty acids have been shown to reduce triglyceride levels and some old trials have shown the benefits of fish oils in reducing cardiovascular events. However, barring a few trials most of the large trials of omega-3 fatty acids are negative. Recently, few large trials have been conducted to see the effects of high dose omega-3 fatty acids on cardiovascular outcomes and some of them have shown promising results on top of LDL reduction.

Triglycerides and endothelial function: molecular biology to clinical perspective

PURPOSE OF REVIEW

Recently, a high level of triglycerides has attracted much attention as an important residual risk factor of cardiovascular events. We will review and show the mechanisms underlying the association of endothelial dysfunction with hypertriglyceridemia and present clinical evidence for a relationship between endothelial function and triglycerides.

RECENT FINDINGS

Clinical studies have shown that hypertriglyceridemia is associated with endothelial dysfunction. It is likely that hypertriglyceridemia impairs endothelial function through direct and indirect mechanisms. Therefore, hypertriglyceridemia is recognized as a therapeutic target in the treatment of endothelial dysfunction. Although experimental and clinical studies have shown that fibrates and omega-3 fatty acids not only decrease triglycerides but also improve endothelial function, the effects of these therapies on cardiovascular events are controversial.

SUMMARY

Accumulating evidence suggests that hypertriglyceridemia is an independent risk factor for endothelial dysfunction. Triglycerides should be considered more seriously as a future target to reduce cardiovascular events. Results of ongoing studies may show the benefit of lowering triglycerides and provide new standards of care for patients with hypertriglyceridemia possibly through improvement in endothelial function.

Sex differences in brain aging and predictors of neurodegeneration in cognitively healthy older adults

We evaluated sex differences in MRI-based volume loss and differences in predictors of this neurodegeneration in cognitively healthy older adults. Mixed-effects regression was used to compare regional brain volume trajectories of 295 male and 328 female cognitively healthy Baltimore Longitudinal Study of Aging participants, aged 55-92 years, with up to 20 years of follow-up and to assess sex differences in the associations of age, hypertension, obesity, APOE e4 carrier status, and high-density lipoprotein cholesterol with regional brain volume trajectories. For both sexes, older age was associated with steeper volumetric declines in many brain regions, with sex differences in volume loss observed in frontal, temporal, and parietal regions. In males, hypertension and higher high-density lipoprotein cholesterol were protective against volume loss in the hippocampus, entorhinal cortex, and parahippocampal gyrus. In females, hypertension was associated with steeper volumetric decline in gray matter, and obesity was protective against volume loss in temporal gray matter. Predictors of volume change may affect annual rates of volume change differently between men and women.

The association between lecithin-cholesterol acyltransferase activity and fatty liver index

Background

Non-alcoholic fatty liver disease is a frequent ailment with known complications, including those within the cardiovascular system. Associations between several indicators of high-density lipoprotein metabolism and function with clinical and laboratory parameters for the assessment of fatty liver index, a surrogate marker of non-alcoholic fatty liver disease, were evaluated.

Methods

The study comprised 130 patients classified according to fatty liver index values: fatty liver index < 30, fatty liver index 30–59 (the intermediate group) and fatty liver index ⩾ 60. Lecithin–cholesterol acyltransferase and cholesteryl ester transfer protein activities were determined. Paraoxonase 1 concentration and its activity, paraoxonase 3 concentration and high-density lipoprotein subclass distribution were assessed.

Results

Increased lecithin–cholesterol acyltransferase activity correlated with increased fatty liver index ( P < 0.001). Paraoxonase 3 concentration was lower in the fatty liver index ⩾ 60 group compared with the fatty liver index < 30 group ( P < 0.05). Cholesteryl ester transfer protein activity, paraoxonase 1 concentration and its activity did not significantly differ across the fatty liver index groups. The relative proportion of small-sized high-density lipoprotein 3 subclass was higher in the fatty liver index ⩾ 60 group compared with the other two fatty liver index groups ( P < 0.01). Lecithin–cholesterol acyltransferase activity positively associated with the fatty liver index ⩾ 60 group and remained significant after adjustment for other potential confounders. Only the triglyceride concentration remained significantly associated with lecithin–cholesterol acyltransferase activity when the parameters that constitute the fatty liver index equation were examined.

Conclusions

Higher lecithin–cholesterol acyltransferase activity is associated with elevated fatty liver index values. Significant independent association between triglycerides and lecithin–cholesterol acyltransferase activity might indicate a role of hypertriglyceridaemia in alterations of lecithin–cholesterol acyltransferase activity in individuals with elevated fatty liver index.

A systematic review: the appraisal of the effects of metformin on lipoprotein modification and function

AIMS

Metformin is a commonly prescribed anti-hyperglycaemic pharmacological agent, and it remains a staple in the management of type II diabetes. In addition to metformin's glucose lowering effects, research has indicated that metformin inhibits glycation-mediated and oxidative modification of lipoprotein residues. The purpose was to discuss the effects of metformin as it relates to high-density lipoprotein (HDL) and low-density lipoprotein (LDL) modification.

MATERIALS AND METHODS

The purpose was to conduct a narrative and pragmatic review on the effects of metformin as it pertains to HDL and LDL modification.

RESULTS

High-density lipoprotein (HDL) concentration is a quantitative measure and therefore does not provide insight into its function, which is a qualitative property. Dysfunctional HDLs are unable to carry out functions normally associated with HDL because they can be modified by glycating agents. Metformin may counteract HDL dysfunction by abating HDL modification. Reductions in HDL modification may improve reverse cholesterol transport ability and thus possibly diminish cardiovascular risk. Similarly, metformin-mediated attenuations in LDL modification may reduce their atherogenic potency.

CONCLUSION

Metformin may partially ameliorate HDL dysfunction and reduce LDL modification by inhibiting alpha-dicarbonyl-mediated modification of apolipoprotein residues; consequently, the results are salient because cardiovascular disease incidence may be reduced given that reverse cholesterol transport activity predicts risk, and modified LDL are proatherogenic.

Residual cardiovascular risk of lipid origin. Components and pathophysiological aspects

There is no doubt about the relationship between LDL-c and cardiovascular risk, as well as about the benefits of statin treatment. Once the objective of LDL-c has been achieved, the evidences that demonstrate the persistence of a high cardiovascular risk, a concept called residual risk, are notable. The residual risk of lipid origin is based on atherogenic dyslipidemia, characterized by an increase in triglycerides and triglyceride-rich lipoproteins, a decrease in HDL-c and qualitative alterations in LDL particles. The most commonly used measures to identify this dyslipidemia are based on the determination of total cholesterol, triglycerides, HDL, non-HDL cholesterol and remaining cholesterol, as well as apolipoprotein B100 and lipoprotein (a) in certain cases. The treatment of atherogenic dyslipidemia is based on weight loss and physical exercise. Regarding pharmacological treatment, we have no evidence of cardiovascular benefit with drugs aimed at lowering triglycerides and HDL-c, fenofibrate seems to be effective in situations of atherogenic dyslipidemia.

Olive oil and postprandial hyperlipidemia: implications for atherosclerosis and metabolic syndrome

Olive oil is the primary source of fat in the Mediterranean diet, which is associated with a significant improvement in health status, as measured by reduced mortality from several chronic diseases. The current pandemic of obesity, metabolic syndrome, and type 2 diabetes is intimately associated with an atherogenic dyslipidemic phenotype. The core components of the dyslipidemia of the metabolic syndrome, which most likely initiate atherosclerosis, are the "lipid triad" consisting of high plasma triglycerides, low levels of high-density lipoproteins, and a preponderance of small, dense low-density lipoproteins at fasting. However, postprandial (non-fasting) TGs (postprandial hyperlipidemia) are also recognized as an important component for atherosclerosis. Herein, the purpose of this review was to provide an update on the effects and mechanisms related to olive oil on postprandial hyperlipidemia and its implications for the onset and progression of atherosclerosis and metabolic syndrome.

Residual Risk of Atherosclerotic Cardiovascular Events in Relation to Reductions in Very-Low-Density Lipoproteins

Background

It is uncertain whether pharmacological reductions in very‐low‐density lipoproteins (VLDLs), and their component triglyceride and cholesterol could reduce residual risk of atherosclerotic cardiovascular disease (ASCVD) events among individuals in whom low‐density lipoprotein cholesterol (LDL‐C) has been adequately lowered. We examined whether individuals with greater on‐statin reductions in VLDL‐related measures—beyond reductions in LDL‐C—were at further reduced risk of ASCVD.

Methods and Results

In 9423 participants in the JUPITER (Justification for the Use of Statins in Prevention) trial (NCT00239681), at baseline and on statin we measured standard lipids, 400‐MHz proton nuclear magnetic resonance spectroscopy‐measured VLDL particle subclasses (small, medium, and large VLDL lipoprotein particle concentration), and total VLDL cholesterol mass. Compared with individuals allocated to placebo, we examined risk of incident ASCVD (N=211) among statin‐allocated participants who achieved minimal (<median) or greater (≥median) marker reductions using adjusted Cox models. On‐statin changes in VLDL‐related markers were only modestly correlated (Spearman r≤0.29) with change in LDL‐C. On‐statin median LDL‐C was 54 mg/dL and triglyceride was 101 mg/dL. Dose‐response reductions in ASCVD risk were observed for greater reductions in LDL‐C, VLDL cholesterol mass, and small VLDL lipoprotein particle concentration; the latter 2 remained significant after incremental adjustment for change in LDL‐C (P≤0.006). Conversely, there was no further risk reduction with greater reductions in triglycerides or large/medium VLDL lipoprotein particle concentration.

Conclusions

Pharmacological reduction in small, cholesterol‐enriched, triglyceride‐depleted VLDL was associated with reduction in ASCVD risk. Chemically measured triglycerides may not sufficiently capture risk related to VLDL pathways. These findings also support broader profiling of lipid and lipoprotein changes in response to statins as prognostic markers of individual benefit, supporting more precision‐medicine, individualized approaches to cardiovascular risk reduction.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00239681.

Hypertriglyceridemia and atherosclerosis

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death and it has been confirmed that increased low density lipoprotein cholesterol (LDL-C) is an independent risk factor for atherosclerosis. Recently, the increasing evidence has showed that hypertriglyceridemia is associated with incremental ASCVD risk. But the proatherogenic mechanism of triglyceride (TG) remains unclear. Therefore, this article focuses on the clinical studies and proatherogenic mechanism related to hypertriglyceridemia, in order to provide reference for the prevention and treatment of ASCVD.

Platelet functional and transcriptional changes induced by intralipid infusion

Multiple studies have shown the effects of long-term exposure to high-fat or western diets on the vascular system. There is limited knowledge on the acute effects of high circulating fat levels, specifically on platelets, which have a role in many processes, including thrombosis and inflammation. This study investigated the effects of acute, high-fat exposure on platelet function and transcript profile. Twenty healthy participants were given an intravenous infusion of 20% Intralipid emulsion and heparin over 6 hours. Blood samples were taken prior to and the day after infusion to measure platelet function and transcript expression levels. Platelet aggregation was not significantly affected by Intralipid infusion, but, when mitochondria function was inhibited by carbonyl cyanide 3-chlorophenylhydrazone (CCCP) or oligomycin, platelet aggregation was higher in the post-infusion state compared to baseline. Through RNA sequencing, and verified by RT-qPCR, 902 miRNAs and 617 mRNAs were affected by Intralipid infusion. MicroRNAs increased include miR-4259 and miR-346, while miR-517b and miR-517c are both decreased. Pathway analysis identified two clusters significantly enriched, including cell motility. In conclusion, acute exposure to high fat affects mitochondrial-dependent platelet function, as well as the transcript profile.

Accumulated substancies and calorific capacity in adipose tissue: Physical and chemical clinical trial

Aim

To study physical and chemical structures and properties including calorific value of human adipose tissue in different anatomical location in autopsy-assigned clinical trial.

Methods

A pilot physical and chemical descriptive randomized autopsy-assigned trial. Adipose tissue 252 sampled from 36 individuals at autopsy who between 36 and 63 years old died from road accidents. Interventions: Chemical functional groups and calorific value were studied using infrared and atomic adsorptive spectrometries, elemental chemical analysis and differential scanning calorimetry. Adipose tissue was sampled from the 7 various anatomical locations.

Results

The highest levels of the analysed chemical substancies were found in dense atherosclerotic plaque. Dense atherosclerotic plaque contains the most of metabolic products, organic and inorganic elements. Dense atherosclerotic plaque has the most of calorific value. The lowest calorific capacity has a pararenal fat.

Conclusions

Human body lipids serve as a harbor for various organic substances, they may absorb different metabolic products, and they have different calorific capacity depending on their location and forms. Atherosclerotic plaque contains the most of organic and inorganic elements, and brings the highest energy potential.

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The body adipose tissue is heterogeneous in content and in property.

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Atherosclerosis plaque contains the largest amount of organic/inorganic functional groups.

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Atherosclerosis plaque is a harbor for various organic substances.

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Adipose tissue has different calorific capacity depending on its locations and forms.

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Plaques bring the highest of energy potential in compare to other fats.

Interactive effects of C-reactive protein levels on the association between APOE variants and triglyceride levels in a Taiwanese population

Background

Apolipoprotein E (APOE) plays a major role in lipid metabolism and inflammation. However, the association between APOE gene polymorphisms and serum triglyceride levels remains controversial. We tested the effects of APOE variants on triglyceride levels and their interactions with the inflammatory marker C-reactive protein (CRP) in a Taiwanese population.

Methods

Two APOE single nucleotide polymorphisms (SNPs) rs429358 and rs7412 were genotyped by TaqMan Assay using real time PCR in 595 healthy subjects attending the clinic for routine visits.

Results

After adjustment for clinical covariates, subjects carrying the rs429358-TT genotype and non-ε4 alleles were found to have higher CRP levels, whereas those with rs7412-CC genotype and non-ε2 alleles had significantly higher total and low-density lipoprotein cholesterol levels (all P < 0.01). Using subgroup and interaction analyses, we observed significantly lower triglyceride levels in subjects carrying the rs429358-TT genotype and non-ε4 alleles in the low CRP group (P = 2.71× 10⁻⁴ and P = 4.32 × 10⁻⁴, respectively), but not in those in the high CRP group (interaction P = 0.013 and 0.045, respectively). In addition, multivariate stepwise linear regression analysis showed that subjects carrying the rs429358-TT genotype and non-ε4 alleles with low CRP levels had significantly lower triglyceride levels (P < 0.001 and P < 0.001, respectively). In addition, when combined with the risk alleles of GCKR, APOA5 and LPL gene variants, we observed that triglyceride levels increased significantly with the number of risk alleles (P = 2.9 × 10⁻¹²).

Conclusions

The combination of SNPs and ε alleles at the APOE locus is involved in managing lipid and CRP levels in the Taiwanese population. APOE polymorphisms interact with CRP to regulate triglyceride levels, thus triglyceride concentration is influenced by both the genetic background of the APOE locus and the inflammatory status of a subject.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-016-0262-z) contains supplementary material, which is available to authorized users.

Triglyceride-rich lipoproteins as a causal factor for cardiovascular disease

Approximately 25% of US adults are estimated to have hypertriglyceridemia (triglyceride [TG] level ≥150 mg/dL [≥1.7 mmol/L]). Elevated TG levels are associated with increased cardiovascular disease (CVD) risk, and severe hypertriglyceridemia (TG levels ≥500 mg/dL [≥5.6 mmol/L]) is a well-established risk factor for acute pancreatitis. Plasma TG levels correspond to the sum of the TG content in TG-rich lipoproteins (TRLs; ie, very low-density lipoproteins plus chylomicrons) and their remnants. There remains some uncertainty regarding the direct causal role of TRLs in the progression of atherosclerosis and CVD, with cardiovascular outcome studies of TG-lowering agents, to date, having produced inconsistent results. Although low-density lipoprotein cholesterol (LDL-C) remains the primary treatment target to reduce CVD risk, a number of large-scale epidemiological studies have shown that elevated TG levels are independently associated with increased incidence of cardiovascular events, even in patients treated effectively with statins. Genetic studies have further clarified the causal association between TRLs and CVD. Variants in several key genes involved in TRL metabolism are strongly associated with CVD risk, with the strength of a variant's effect on TG levels correlating with the magnitude of the variant's effect on CVD. TRLs are thought to contribute to the progression of atherosclerosis and CVD via a number of direct and indirect mechanisms. They directly contribute to intimal cholesterol deposition and are also involved in the activation and enhancement of several proinflammatory, proapoptotic, and procoagulant pathways. Evidence suggests that non-high-density lipoprotein cholesterol, the sum of the total cholesterol carried by atherogenic lipoproteins (including LDL, TRL, and TRL remnants), provides a better indication of CVD risk than LDL-C, particularly in patients with hypertriglyceridemia. This article aims to provide an overview of the available epidemiological, clinical, and genetic evidence relating to the atherogenicity of TRLs and their role in the progression of CVD.

Acute hyperlipidemia initiates proinflammatory and proatherogenic changes in circulation and adipose tissue in obese women

BACKGROUND

Obesity represents a high risk factor for the development of atherosclerosis and is associated with a low-grade inflammation and activation of immune cells.

AIMS

The aim of our study was to investigate the effect of a short-term lipid infusion on immune cells in blood and subcutaneous abdominal adipose tissue (SAAT) in obese women.

METHODS

Seven-hour intravenous lipid/control infusions were performed in two groups of women (n = 15, n = 10, respectively). Before and at the end of the infusion, SAAT and blood samples were obtained and relative content and phenotype of immune cells were analyzed using flow cytometry. Analysis of immune cell markers, inflammation and angiogenesis markers was performed in SAAT by RT-PCR and in plasma by immunoassays.

RESULTS

Relative content of CD45+/14+ and CD45+/14+/16+ populations of monocytes was reduced in circulation by 21% (p = 0.004) and by 46% (p = 0.0002), respectively, in response to hyperlipidemia, which suggested the increased adhesion of these cells to endothelium. In line with this, the levels of sICAM and sVCAM in plasma were increased by 9.4% (p = 0.016), 11.8% (p = 0.008), respectively. In SAAT, the relative content of M2 monocyte/macrophages subpopulation CD45+/14+/206+/16+ decreased by 27% (p = 0.012) and subpopulations CD14+/CD206- and CD14/+TLR4+ cells increased (p = 0.026; p = 0.049, respectively). Intralipid infusion promoted an increase of mRNA levels in SAAT: RORC (marker of proinflammatory Th17 lymphocytes) by 43% (p = 0.048), MCP-1 (78%, p = 0.028) and VEGF (68.5%, p = 0.0001).

CONCLUSIONS

Acute hyperlipidemia induces a proinflammatory and proatherogenic response associated with altered relative content of immune cells in blood and SAAT in obese women.

Dysfunctional HDL and atherosclerotic cardiovascular disease

High-density lipoproteins (HDLs) protect against atherosclerosis by removing excess cholesterol from macrophages through the ATP-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1) pathways involved in reverse cholesterol transport. Factors that impair the availability of functional apolipoproteins or the activities of ABCA1 and ABCG1 could, therefore, strongly influence atherogenesis. HDL also inhibits lipid oxidation, restores endothelial function, exerts anti-inflammatory and antiapoptotic actions, and exerts anti-inflammatory actions in animal models. Such properties could contribute considerably to the capacity of HDL to inhibit atherosclerosis. Systemic and vascular inflammation has been proposed to convert HDL to a dysfunctional form that has impaired antiatherogenic effects. A loss of anti-inflammatory and antioxidative proteins, perhaps in combination with a gain of proinflammatory proteins, might be another important component in rendering HDL dysfunctional. The proinflammatory enzyme myeloperoxidase induces both oxidative modification and nitrosylation of specific residues on plasma and arterial apolipoprotein A-I to render HDL dysfunctional, which results in impaired ABCA1 macrophage transport, the activation of inflammatory pathways, and an increased risk of coronary artery disease. Understanding the features of dysfunctional HDL or apolipoprotein A-I in clinical practice might lead to new diagnostic and therapeutic approaches to atherosclerosis.

Physiology in Medicine: update on lifestyle determinants of postprandial triacylglycerolemia with emphasis on the Mediterranean lifestyle

This review updates the effect of lifestyle on plasma triacylglycerols (TAG) in the postprandial state, commonly reported as postprandial lipemia (PPL), an independent risk factor for cardiovascular diseases (CVD). Numerous studies have shown that Mediterranean diet may reduce PPL. However, most of these studies were focused on the type of fat (i.e., monounsaturated fat from olive oil), and the other components of the Mediterranean lifestyle were neglected. Physical activity, an integral part of this lifestyle, is widely investigated on its own and shown to reduce PPL. In addition, preliminary results of studies examining other Mediterranean "ingredients", such as legumes, fish, and herbs, showed additional benefits; however, data on the long-term effects are limited. More studies are needed to confirm short-term results and investigate the effects of the whole Mediterranean lifestyle on PPL and whether these effects mediate its protective role on CVD. Moreover, investigation of the effects in nonhealthy populations and the underlying mechanisms would be clinically helpful in individualizing the appropriate intervention.

Postprandial lipemia as a cardiometabolic risk factor

High levels of fasting circulating triglycerides (TG) represent an independent risk factor for cardiovascular disease. In western countries, however, people spend most time in postprandial conditions, with continuous fluctuation of lipemia due to increased levels of TG-rich lipoproteins (TRLs), including chylomicrons (CM), very low density lipoproteins (VLDL), and their remnants. Several factors contribute to postprandial lipid metabolism, including dietary, physiological, pathological and genetic factors. The presence of coronary heart disease, type 2 diabetes, insulin resistance and obesity is associated with higher postprandial TG levels compared with healthy conditions; this association is present also in subjects with normal fasting TG levels. Increasing evidence indicates that impaired metabolism of postprandial lipoproteins contributes to the pathogenesis of coronary artery disease, suggesting that lifestyle modifications as well as pharmacological approaches aimed at reducing postprandial TG levels might help to decrease the cardiovascular risk.

eNOS activation by HDL is impaired in genetic CETP deficiency

Mutations in the CETP gene resulting in defective CETP activity have been shown to cause remarkable elevations of plasma HDL-C levels, with the accumulation in plasma of large, buoyant HDL particles enriched in apolipoprotein E. Genetic CETP deficiency thus represents a unique tool to evaluate how structural alterations of HDL impact on HDL atheroprotective functions. Aim of the present study was to assess the ability of HDL obtained from CETP-deficient subjects to protect endothelial cells from the development of endothelial dysfunction. HDL isolated from one homozygous and seven heterozygous carriers of CETP null mutations were evaluated for their ability to down-regulate cytokine-induced cell adhesion molecule expression and to promote NO production in cultured endothelial cells. When compared at the same protein concentration, HDL and HDL3 from carriers proved to be as effective as control HDL and HDL3 in down-regulating cytokine-induced VCAM-1, while carrier HDL2 were more effective than control HDL2 in inhibiting VCAM-1 expression. On the other hand, HDL and HDL fractions from carriers of CETP deficiency were significantly less effective than control HDL and HDL fractions in stimulating NO production, due to a reduced eNOS activating capacity, likely because of a reduced S1P content. In conclusion, the present findings support the notion that genetic CETP deficiency, by affecting HDL particle structure, impacts on HDL vasculoprotective functions. Understanding of these effects might be important for predicting the outcomes of pharmacological CETP inhibition.

Residual macrovascular risk in 2013: what have we learned?

Cardiovascular disease poses a major challenge for the 21st century, exacerbated by the pandemics of obesity, metabolic syndrome and type 2 diabetes. While best standards of care, including high-dose statins, can ameliorate the risk of vascular complications, patients remain at high risk of cardiovascular events. The Residual Risk Reduction Initiative (R3i) has previously highlighted atherogenic dyslipidaemia, defined as the imbalance between proatherogenic triglyceride-rich apolipoprotein B-containing-lipoproteins and antiatherogenic apolipoprotein A-I-lipoproteins (as in high-density lipoprotein, HDL), as an important modifiable contributor to lipid-related residual cardiovascular risk, especially in insulin-resistant conditions. As part of its mission to improve awareness and clinical management of atherogenic dyslipidaemia, the R3i has identified three key priorities for action: i) to improve recognition of atherogenic dyslipidaemia in patients at high cardiometabolic risk with or without diabetes; ii) to improve implementation and adherence to guideline-based therapies; and iii) to improve therapeutic strategies for managing atherogenic dyslipidaemia. The R3i believes that monitoring of non-HDL cholesterol provides a simple, practical tool for treatment decisions regarding the management of lipid-related residual cardiovascular risk. Addition of a fibrate, niacin (North and South America), omega-3 fatty acids or ezetimibe are all options for combination with a statin to further reduce non-HDL cholesterol, although lacking in hard evidence for cardiovascular outcome benefits. Several emerging treatments may offer promise. These include the next generation peroxisome proliferator-activated receptorα agonists, cholesteryl ester transfer protein inhibitors and monoclonal antibody therapy targeting proprotein convertase subtilisin/kexin type 9. However, long-term outcomes and safety data are clearly needed. In conclusion, the R3i believes that ongoing trials with these novel treatments may help to define the optimal management of atherogenic dyslipidaemia to reduce the clinical and socioeconomic burden of residual cardiovascular risk.

Prediabetes: grounds of pitfall signalling alteration for cardiovascular disease

Prediabetes manifested by impaired glucose tolerance and impaired fasting glucose offers high risk of myocardial dysfunction by causing endothelial dysfunction, inflammation, oxidative stress, atherosclerosis and genetic alterations.

Differential effects of low-fat and high-fat diets on fed-state hepatic triacylglycerol secretion, hepatic fatty acid profiles, and DGAT-1 protein expression in obese-prone Sprague-Dawley rats

The purpose of this study was to compare the effects of short-term low-fat (LF) and high-fat (HF) diets on fed-state hepatic triacylglycerol (TAG) secretion, the content of proteins involved in TAG assembly and secretion, fatty acid oxidation (FAO), and the fatty acid profile of stored TAG. Using selectively bred obese-prone Sprague-Dawley rats, we directly measured fed-state hepatic TAG secretion, using Tyloxapol (a lipoprotein lipase inhibitor) and a standardized oral mixed meal (45% carbohydrate, 40% fat, 15% protein) bolus in animals fed a HF or LF diet for 2 weeks, after which the rats were maintained on their respective diet for 1 week (washout) prior to the liver being excised to measure protein content, FAO, and TAG fatty acid profiles. Hepatic DGAT-1 protein expression was ∼27% lower in HF- than in LF-fed animals (p < 0.05); the protein expression of all other molecules was similar in the 2 diets. The fed-state hepatic TAG secretion rate was ∼39% lower (p < 0.05) in HF- (4.62 ± 0.18 mmol·h(-1)) than in LF- (7.60 ± 0.57 mmol·h(-1)) fed animals. Hepatic TAG content was ∼2-fold higher (p < 0.05) in HF- (1.07 ± 0.15 nmol·g(-1) tissue) than in LF- (0.50 ± 0.16 nmol·g(-1) tissue) fed animals. In addition, the fatty acid profile of liver TAG in HF-fed animals closely resembled the diet, whereas in LF-fed animals, the fatty acid profile consisted of mostly de novo synthesized fatty acids. FAO was not altered by diet. LF and HF diets differentially alter fed-state hepatic TAG secretion, hepatic fatty acid profiles, and DGAT-1 protein expression.

Sex differences in the associations between lipid levels and incident dementia

Cholesterol is a risk factor for developing vascular pathologies, which is in turn an important risk factor for dementia. Previous studies linking lipids and dementia have yielded inconsistent results, which may be attributable to sex differences in the etiology of both vascular disease and dementia. The aim of this study was to evaluate the associations between lipids and incident dementia in 7053 community-dwelling elderly. Dementia was diagnosed at baseline, and 2, 4, and 7-year follow-up. Multivariate Cox models stratified by sex and history of vascular pathologies at baseline were adjusted for sociodemographic, mental and physical health variables, and genetic vulnerability. In men without vascular pathologies, an increased incidence of all-cause dementia but not Alzheimer's disease (AD) was associated with high triglyceride (TG) (HR = 1.55, 95% CI = 1.04-2.32, p = 0.03) and low HDL-cholesterol levels (HR = 1.49, 95% CI = 0.99-2.23, p = 0.05). In women without vascular pathologies, low TG levels were associated with a decreased risk of AD (HR = 0.65, 95% CI = 0.43-0.97, p = 0.03). A decreased risk was also found with high TG levels which may depend on genetic vulnerability to dyslipidemia related to APOA5. For both sexes, no significant associations were found between total- or LDL-cholesterol and dementia or AD. Low HDL-cholesterol and high TG levels may be risk factors of dementia in elderly men whereas low TG is associated with decreased incident AD in women. This data suggests a complex sex-specific etiology of vascular dementia and AD.

Increased burden and severity of metabolic syndrome and arterial stiffness in treatment-naïve HIV+ patients from Cameroon

BACKGROUND

Human immunodeficiency virus (HIV) and its therapy are associated with increased aortic stiffness and metabolic syndrome (MetS) phenotype in Caucasian patients. We hypothesized that, independently of antiretroviral therapy, HIV infection in native black African patients is associated with increased burden of cardiometabolic risk factors that may accelerate arterial structural damage and translate into increased aortic stiffness.

PATIENTS AND METHODS

Ninety-six apparently healthy Cameroonian subjects (controls) were compared to 108 untreated Cameroonian HIV+ patients (HIV-UT) of similar age. In each participant, pulse wave velocity (Complior), aortic augmentation index (SphygmoCor), brachial blood pressure (Omron 705 IT), fasting plasma glucose (FPG), and lipids were recorded, as well as the prevalence and severity of MetS, based on the American Heart Association/National Heart, Lung, and Blood Institute score ≥3/5.

RESULTS

Prevalence of impaired fasting glucose (FPG 100-125 mg · dL⁻¹) and of diabetes (FPG > 125 mg · dL⁻¹) was higher in HIV-UT than in controls (47% versus 27%, and 26% versus 1%, respectively; both P < 0.01). Fasting triglycerides and the atherogenic dyslipidemia ratio were significantly higher in HIV-UT than in controls. Hypertension prevalence was high and comparable in both groups (41% versus 44%, respectively; not significant). HIV-UT patients exhibited a twice-higher prevalence of MetS than controls (47% versus 21%; P = 0.02). Age- and sex-adjusted pulse wave velocity was higher in HIV-UT than in controls (7.5 ± 2.2 m/s versus 6.9 ± 1.7 m/s, respectively; P = 0.02), whereas aortic augmentation index was significantly lower (6% ± 4% versus 8% ± 7%, respectively; P = 0.01).

CONCLUSION

Similar to Caucasian populations, native Cameroonian HIV-UT patients showed a higher prevalence of MetS and its phenotype, associated with increased aortic stiffness, an early marker of atherosclerosis.

The effect of high-calorie meal consumption on oxidative stress and endothelial dysfunction in healthy male adults

Several authors have reported the association of postprandial hypertriglyceridemia with oxidative stress, systemic inflammation and endothelial dysfunction. Our aim was to investigate the effect of high-calorie meal on blood markers of oxidative stress and endothelial dysfunction and the association of APOA5 -1131T/C and -250G/A hepatic lipase (HL) polymorphisms with postprandial triglyceride response. This study included 102 healthy male volunteers. All participants consumed a high-calorie meal (823 calories, 50 g fat, 28 g protein, 60 g carbohydrates). Total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, hsCRP, TAS and ICAM-1 were measured at fasting state and postprandially. APOA5 -1131T/C and -250G/A HL polymorphisms were also determined. Postprandial triglycerides were significantly increased (1.4 (1.1-2.1) vs. 2.4 (1.9-3.3) mmol/l, P<0.001). Average triglyceride increase was 1.0+/-0.7 mmol/l (65 %). Concentration of triglycerides, HDL-cholesterol, LDL-cholesterol, TAS and ICAM-1 differed significantly between the fasting state and postprandial measurements (P<0.001). However, those differences were within the limits of analytical imprecision. Other parameters did not change 3 h after the meal. Triglycerides response did not differ respective to the APOA5 and HL polymorphisms. Family history of hypertension and acute myocardial infarction were associated with higher postprandial triglyceride concentrations. Postprandial hypertriglyceridemia is not associated with increased concentrations of hsCRP, TAS and ICAM-1. Furthermore, APOA5 -1131T/C and -250G/A HL polymorphisms are not associated with different postprandial triglyceride response.

Epanova® and hypertriglyceridemia: pharmacological mechanisms and clinical efficacy

While LDL-cholesterol lowering has become the cornerstone of cardiovascular risk reduction strategies, considerable interest in additional targeting of hypertriglyceridemia continues. While ω-3 fatty acids are commonly used in clinical practice for triglyceride lowering, no large-scale clinical trial evaluating their impact on clinical events has been performed. As a result, there remains a lack of consensus with regards to their optimal clinical use. Epanova® (Omthera Pharmaceuticals Inc., NJ, USA) is a novel ω-3 free fatty acid formulation, developed to maximize eicosapentenoic acid and docosahexenoic acid bioavailability with low-fat diets, suggesting a potential therapeutic advantage compared with ω-3-acid ethyl esters in the treatment of patients with hypertriglyceridemia. Additional human studies are needed to define more clearly the cellular and molecular basis for the triglyceride-lowering effects of Epanova and this drug’s favorable cardiovascular effects, particularly in patients with hypertriglyceridemia.

Association of postalimentary lipemia with atherosclerotic manifestations

We identified different lipemic and metabolic responses after the ingestion of a standardized meal by healthy adults and related them to atherosclerotic markers. Samples from 60 normolipidemic adults were collected before and after a liquid meal (40 g fat/m² body surface) at 0, 2, 4, 6, and 8 h for measurements of lipids, free fatty acids (FFA), insulin, cholesteryl ester transfer protein (CETP), autoantibodies to epitopes of oxidized LDL (oxLDL Ab), lipolytic activities, and apolipoprotein E polymorphism. Mean carotid intima-media thickness (cIMT) was determined by Doppler ultrasound. The volunteers were classified into early (N = 39) and late (N = 31) triacylglycerol (TAG) responders to the test meal. Late responders showed lower HDL cholesterol concentration at fasting and in the TAG peak, lower insulin and higher FFA concentrations compared to early responders. Multivariate regression analyses showed that mean cIMT was associated with gender (male) and age in early responders and by cholesterol levels at the 6th hour in late responders. oxLDL Ab were explained by lipoprotein lipase and negatively by hepatic lipase and oxLDL Ab (fasting period) by CETP (negative) and FFA (positive). This study is the first to identify a postalimentary insulin resistance state, combined with a reduced CETP response exclusively among late responders, and the identification of the regulators of postalimentary atherogenicity. Further research is required to determine the metabolic mechanisms described in the different postalimentary phenotypes observed in this study, as well as in different pathological states, as currently investigated in our laboratory.