Association between postprandial triglycerides and coronary artery disease detected by coronary computed tomography angiography

Family history of diabetes determines the association of HOMA-IR with fasting and postprandial triglycerides in individuals with normal glucose tolerance

BACKGROUND

Individuals with family history of diabetes carry nearly double the risk of diabetes than those without. However, the mechanism for this increased risk of diabetes in them is not fully understood.

OBJECTIVE

To study fasting and postprandial triglyceride levels in individuals with normal glucose tolerance (NGT) who had family history of diabetes and to ascertain their association with insulin resistance.

METHODS

Fasting triglyceride levels and HOMA-IR were compared in 671 NGT individuals with and without a family history of diabetes. A standardized fat challenge test was also done in one tenth of individuals of each group and postprandial triglyceride responses were compared between them. Association of HOMA-IR with fasting and postprandial triglyceride levels was ascertained through pearson's coefficient of correlation.

RESULTS

Individuals with family history of diabetes had significantly higher HOMA-IR (P < 0.001) and significantly higher postprandial triglyceride AUC (P = 0.04) after standardized fat meal despite having similar fasting triglyceride levels (P = 0.51) as those without family history of diabetes. Fasting as well as postprandial triglyceride levels significantly correlated with HOMA-IR (r = 0.35, P < 0.001 and r = 0.39, P = 0.04) only in those with a positive family history of diabetes but not in those without. Triglyceride levels mediated the associations of BMI (Δ β = -0.053) and waist circumference (Δ β = -0.075) with HOMA-IR.

CONCLUSION

Triglyceride levels, both in the fasting and the postprandial state are associated with insulin resistance in NGT individuals with a family history of diabetes but not in those without.

Triglycerides and triglyceride-rich lipoproteins in the development and progression of atherosclerosis

PURPOSE OF REVIEW

In this review, we intend to show the heterogenicity of the triglyceride group, including the triglyceride-rich lipoproteins and its subparticles, apolipoproteins, and its role in atherogenesis through epidemiological and genetic studies, observing the association of these various components and subclasses with subclinical atherosclerosis and cardiovascular events. Also, we reevaluated the moment of blood collection for the triglyceride measurement and its repercussion in atherosclerosis. Finally, we present the current scenario and new insights about the pharmacologic treatment of hypertriglyceridemia.

RECENT FINDINGS

Recent studies have been observed, a correlation between cardiovascular disease and triglyceride components (as apolipoproteins A-V, C-I, C-III) as well as proteins involved in the metabolism pathway, such as the angiopoietin-like proteins. Also, the triglyceride-rich lipoproteins, also known as remnants, were recently associated with atherogenesis. Another important topic addressed is about nonfasting triglyceride level, which has been postulated as a better predictor of cardiovascular events than fasting collection.

SUMMARY

Regarding hypertriglyceridemia treatment, the drug therapy was updated, as the omega-3 polyunsaturated fatty acids were tested in primary prevention as eicosapentaenoic acid and docosahexaenoic acid combination resulted in no benefit, whereas the administration of icosapent ethyl in secondary prevention and high-risk patients showed a robust decrease of the cardiovascular outcomes.

Low HDL-C levels are associated with cervicocerebral atherosclerotic stenosis in Southern Chinese patients with large artery atherosclerotic ischemic stroke

OBJECTIVES

The aim of this study is to investigate the association of HDL-C with CCAS, as well as its intracranial or extracranial location in the Southern Chinese population.

PATIENTS AND METHODS

123 Southern Chinese patients with large-artery atherosclerotic(LAA) ischemic stroke were enrolled for the final analysis. Based on the stenosis severity defined by digital subtraction angiography, the patients were categorized into CCAS and non-CCAS groups. The degree of artery stenosis among patients of CCAS was classified into three grades. CCAS were further categorized into intracranial AS (ICAS), Extracranial AS (ECAS) and combined intra-/extra-cranial AS (IECAS).

RESULTS

It was showed that patients with CCAS had a lower HDL-C level compared to NCCAS, and HDL-C levels were correlated to the degree of artery stenosis among CCAS. After adjusting for multiple potential confounders, low HDL-C level remained independently associated with CCAS(adjusted OR = 2.860). Patients with the lowest HDL-C quartile had a significantly increased risk for CCAS(adjusted OR: 5.771), referred to the highest quartile. But HDL-C levels in patients with ICAS, ECAS and IECAS were not significantly different, and there was no significant correlation between HDL-C levels and ICAS.

CONCLUSION

Our data indicate that low HDL-C level is associated with CCAS in Southern Chinese patients with LAA ischemic stroke. But the effects of HDL-C on the distribution of CCAS is required to be further explored.

Coronary computed tomography angiography detection of short- and long-term outcomes after heart valve surgery with high risk cardiovascular patients

Coronary computed tomography angiography (CCTA) is a promising alternative technique to detect significant coronary artery lesions in high-risk cardiovascular patients with left ventricular dysfunction (left ventricular ejection fractions < 40%) referred for elective valve surgery, while little research about the use of CCTA to detect the outcomes of heart valve surgery was performed. Forty-six consecutive high-risk cardiovascular patients with the New York Heart Association (NYHA) classification were retrospectively studied. Immediate, 10-week, 20-week, and 40-week outcomes after heart valve surgery were assessed with CCTA. Patients' average age at the time of surgery was 73 years, with the majority being male (54.35%). Among the CCTA parameters detected after 10, 20, and 40 weeks after heart valve surgery, only segment involvement score (SIS) did reach statistical significance when compared with baseline levels. The cumulative mortality rate at 10, 20, and 40 weeks were 19.56%, 30.43%, and 39.13% respectively. It can be seen that the early death is mainly due to complications, and with the time-lapse of surgery, the impact of complications on death is gradually eliminated. CCTA might be a useful tool to detect the outcomes of short- and long-term outcomes after heart valve surgery with high risk cardiovascular patients, and SIS level is associated with the short- and long-term outcomes.

Atherogenic postprandial remnant lipoproteins; VLDL remnants as a causal factor in atherosclerosis

Oxidized LDL (Ox-LDL) and chylomicron (CM) remnants have been suggested to be the most atherogenic lipoproteins that initiate and exacerbate coronary atherosclerosis. In this review, we propose a hypothesis of the causal lipoproteins in atherosclerosis based on our recent findings on postprandial remnant lipoproteins (RLP). Plasma RLP-C and RLP-TG increased significantly after food intake, especially a fat load. More than 80% of the TG increase after the fat load consisted of the TG in RLP, which contained significantly greater apoB100 than apoB48 particles as VLDL remnants. The majority of the LPL in non-heparin plasma was found in RLP as an RLP-LPL complex and released into the circulation after hydrolysis. Plasma LPL did not increase after food intake, which may have caused the partial hydrolysis of CM and VLDL as well as the significant increase of RLP-TG in the postprandial plasma. LPL was inversely correlated with the RLP particle size after food intake. We showed that VLDL remnants are the major atherogenic lipoproteins in the postprandial plasma associated with insufficient LPL activity and a causal factor in the initiation and progression of atherosclerosis. We also propose "LPL bound TG-rich lipoproteins" as a new definition of remnant lipoproteins based on the findings of the RLP-LPL complex in the non-heparin plasma.

ANGPTL3 serum concentration and rare genetic variants in Finnish population

Genetic variants of angiopoietin-like protein 3 (ANGPTL3) are associated with serum triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) concentration in GWASs. ANGPTL3 deficiency causes declined TG, total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol (HDL-C), apolipoprotein B (apoB) and apolipoprotein A-I (apoA-I) serum concentration, a phenotype defined as familial combined hypolipidaemia (FHBL2). Our aim is to establish whether ANGPTL3 serum protein concentration correlates with lipoproteins and lipids in hyper- or hypolipidaemic subjects, and whether ANGPTL3 sequence variants are associated with untypical lipid profiles. Additionally, 10 subjects with very low lipoprotein concentrations were sequenced for ANGPTL3 for possible loss-of-function (LOF) variants. Study subjects were selected from Finnish FINRISK and Health 2000 surveys. ANGPTL protein concentrations were measured by ELISA method. As a result, ANGPTL3 serum concentration correlated positively with age, phospholipid transfer protein (PLTP) and cholesteryl ester transfer protein (CETP) activities, but not with any of the lipid or lifestyle attributes. No ANGPTL3 variants were found among sequenced samples. Subjects who carried ANGPTL3 sequence variants rs12563308 (n = 4) and rs199772471 (n = 1) had abnormally high TC and LDL-C concentrations. Whole exome sequencing data of these five subjects were further analyzed for rare and deleterious missense variants in genes associated with cholesterol metabolism. In conclusion, ANGPTL3 serum protein concentration did not predict lipid concentrations, unlike apolipoprotein C-III (apoC-III) which positively correlated with most of the lipid attributes. ANGPTL3 variant screen yielded five carriers with abnormally high TC concentration; the actual genetic causality, however, could not be verified.

Relation of Fasting Triglyceride-Rich Lipoprotein Cholesterol to Coronary Artery Calcium Score (from the ELSA-Brasil Study)

Although low-density lipoprotein cholesterol (LDL-C) is widely accepted as the principal lipid fraction associated with atherosclerosis, emerging evidence suggests a causal relation between lifelong elevations in triglyceride-rich lipoprotein cholesterol (TRL-C) and cardiovascular disease (CVD) in genetic studies. To provide further evidence for the potential relevance of TRL-C and atherosclerosis, we have evaluated the relation between TRL-C and coronary artery calcium (CAC) score. We included 3,845 subjects (49.9 ± 8.4 years, 54% women) who had no history of CVD, were not using lipid-lowering medications, and underwent CAC evaluation. We assessed the relation between increasing fasting TRL-C and the graded increase in CAC and to what extent TRL-C were independently associated with CAC over and above LDL-C using logistic regression models. Overall, 973 (25%) of the participants had a CAC >0 and 308 (8%) had a CAC >100. The median TRL-C level was 22 mg/dL (IQR 16 to 32). Subjects with CAC >0 had higher TRL-C levels than those with CAC = 0 (p <0.001). Similarly, subjects with CAC >0 had higher levels of LDL-C, non-high-density lipoprotein cholesterol, and lower high-density lipoprotein cholesterol (all p <0.001). After multivariate adjustment, log-transformed TRL-C remained associated with the presence and severity of CAC (all p <0.05). When TRL-C was added to models that contained demographic factors and conventional lipids, it significantly improved the model to predict the presence of CAC >0 (p = 0.01). In conclusion, in a large cohort of asymptomatic subjects, TRL-C was associated with subclinical atherosclerosis supporting a potentially causal role in CVD.

Association between interleukin-6 and the risk of cardiac events measured by coronary computed tomography angiography

Interleukin-6 (IL-6) has been found to be a predictor of heart attack. We aimed to investigate the relationship of risk factor IL-6 with extent and severity of the coronary artery disease (CAD) evaluated using coronary computed tomography angiography (CCTA). A total of 303 participants without history of CAD undergoing CCTA were enrolled. Using the model of risk-adjusted Cox proportional-hazards, the association of IL-6 level with major adverse cardiac events (MACE) was detected. The participants were assigned into three study groups based on serum IL-6 level. Compared with those in the lowest tertile, patients with highest IL-6 level displayed higher atherosclerotic burden such as plaque extent defined as prevalence of obstructive CAD and segments with any plaque. After a median 3.0 year follow-up period, we also found that patients with highest IL-6 level experienced higher MACE risk and all-cause death compared with those from the lowest tertile. Among participants without CAD history who underwent CCTA, patients with high level of IL-6 had increased burden of atherosclerosis and higher MACE risk compared to participants of low level of IL-6.

Increasing insulin resistance accentuates the effect of triglyceride-associated loci on serum triglycerides during 5 years

Blood concentrations of triglycerides are influenced by genetic factors as well as a number of environmental factors, including adiposity and glucose homeostasis. The aim was to investigate the association between a serum triglyceride weighted genetic risk score (wGRS) and changes in fasting serum triglyceride level over 5 years and to test whether the effect of the wGRS was modified by 5 year changes of adiposity, insulin resistance, and lifestyle factors. A total of 3,474 nondiabetic individuals from the Danish Inter99 cohort participated in both the baseline and 5 year follow-up physical examinations and had information on the wGRS comprising 39 genetic variants. In a linear regression model adjusted for age, sex, and baseline serum triglyceride, the wGRS was associated with increased serum triglyceride levels over 5 years [per allele effect = 1.3% (1.0-1.6%); P = 1.0 × 10-17]. This triglyceride-increasing effect of the wGRS interacted with changes in insulin resistance (Pinteraction = 1.5 × 10-6). This interaction indicated that the effect of the wGRS was stronger in individuals who became more insulin resistant over 5 years. In conclusion, our findings suggest that increased genetic risk load is associated with a larger increase in fasting serum triglyceride levels in nondiabetic individuals during 5 years of follow-up. This effect of the wGRS is accentuated by increasing insulin resistance.

European Society of Cardiology-Recommended Coronary Artery Disease Consortium Pretest Probability Scores More Accurately Predict Obstructive Coronary Disease and Cardiovascular Events Than the Diamond and Forrester Score: The Partners Registry

BACKGROUND

The most appropriate score for evaluating the pretest probability of obstructive coronary artery disease (CAD) is unknown. We sought to compare the Diamond-Forrester (DF) score with the 2 CAD consortium scores recently recommended by the European Society of Cardiology.

METHODS

We included 2274 consecutive patients (age, 56±13 years; 57% male) without prior CAD referred for coronary computed tomographic angiography. Computed tomographic angiography findings were used to determine the presence or absence of obstructive CAD (≥50% stenosis). We compared the DF score with the 2 CAD consortium scores with respect to their ability to predict obstructive CAD and the potential implications of these scores on the downstream use of testing for CAD, as recommended by current guidelines.

RESULTS

The DF score did not satisfactorily fit the data and resulted in a significant overestimation of the prevalence of obstructive CAD (P<0.001); the CAD consortium basic score had no significant lack of fitness; and the CAD consortium clinical provided adequate goodness of fit (P=0.39). The DF score had a lower discrimination for obstructive CAD, with an area under the receiver-operating characteristics curve of 0.713 versus 0.752 and 0.791 for the CAD consortium models (P<0.001 for both). Consequently, the use of the DF score was associated with fewer individuals being categorized as requiring no additional testing (8.3%) compared with the CAD consortium models (24.6% and 30.0%; P<0.001). The proportion of individuals with a high pretest probability was 18% with the DF and only 1.1% with the CAD consortium scores (P<0.001) CONCLUSIONS: Among contemporary patients referred for noninvasive testing, the DF risk score overestimates the risk of obstructive CAD. On the other hand, the CAD consortium scores offered improved goodness of fit and discrimination; thus, their use could decrease the need for noninvasive or invasive testing while increasing the yield of such tests.

The role of ANGPTL3 in controlling lipoprotein metabolism

Angiopoietin-like protein 3 (ANGPTL3) is a secretory protein regulating plasma lipid levels via affecting lipoprotein lipase- and endothelial lipase-mediated hydrolysis of triglycerides and phospholipids. ANGPTL3-deficiency due to loss-of-function mutations in the ANGPTL3 gene causes familial combined hypobetalipoproteinemia (FHBL2, OMIM # 605019), a phenotype characterized by low concentration of all major lipoprotein classes in circulation. ANGPTL3 is therefore a potential therapeutic target to treat combined hyperlipidemia, a major risk factor for atherosclerotic coronary heart disease. This review focuses on the mechanisms behind ANGPTL3-deficiency induced FHBL2.