High-density lipoprotein subclasses and their relationship to cardiovascular disease

Low HDL-C/ApoA-I index is associated with cardiometabolic risk factors and coronary artery calcium: a sub-analysis of the genetics of atherosclerotic disease (GEA) study

BACKGROUND

The high-density lipoprotein cholesterol to apolipoprotein A-I index (HDL-C/ApoA-I) may be practical and useful in clinical practice as a marker of atherosclerosis. This study aimed to investigate the association between the HDL-C/ApoA-I index with cardiometabolic risk factors and subclinical atherosclerosis.

METHODS

In this cross-sectional sub-analysis of the GEA study, 1,363 individuals, women (51.3%) and men (48.7%) between 20 and 75 years old, without coronary heart disease or diabetes mellitus were included. We defined an adverse cardiometabolic profile as excess adipose tissue metrics, non-alcoholic liver fat measured by non-contrasted tomography, metabolic syndrome, dyslipidemias, and insulin resistance. The population was stratified by quartiles of the HDL-C/Apo-AI index, and its dose-relationship associations were analysed using Tobit regression, binomial, and multinomial logistic regression analysis.

RESULTS

Body mass index, visceral and pericardial fat, metabolic syndrome, fatty liver, high blood pressure, and CAC were inversely associated with the HDL-C/ApoA-I index. The CAC > 0 prevalence was higher in quartile 1 (29.2%) than in the last quartile (22%) of HDL-C/ApoA-I index (p = 0.035). The probability of having CAC > 0 was higher when the HDL-C/ApoA-I index was less than 0.28 (p < 0.001). This association was independent of classical coronary risk factors, visceral and pericardial fat measurements.

CONCLUSION

The HDL-C/ApoA-I index is inversely associated with an adverse cardiometabolic profile and CAC score, making it a potentially useful and practical biomarker of coronary atherosclerosis. Overall, these findings suggest that the HDL-C/ApoA-I index could be useful for evaluating the probability of having higher cardiometabolic risk factors and subclinical atherosclerosis in adults without CAD.

Impaired Cholesterol Uptake Capacity in Patients with Hypertriglyceridemia and Diabetes Mellitus

BACKGROUND

Although low high-density lipoprotein cholesterol (HDL-C) levels are a common metabolic abnormality associated with insulin resistance, their role in cardiovascular risk stratification remains controversial. Recently, we developed a simple, high-throughput, cell-free assay system to evaluate the "cholesterol uptake capacity (CUC)" as a novel concept for HDL functionality. In this study, we assessed the CUC in patients with hypertriglyceridemia and diabetes mellitus.

METHODS

The CUC was measured using cryopreserved serum samples from 285 patients who underwent coronary angiography or percutaneous coronary intervention between December 2014 and May 2019 at Kobe University Hospital.

RESULTS

The CUC was significantly lower in diabetic patients (n = 125) than in nondiabetic patients (93.0 vs 100.7 arbitrary units (A.U.), P = 0.002). Patients with serum triglyceride (TG) levels >150 mg/dL (n = 94) also had a significantly lower CUC (91.8 vs 100.0 A.U., P = 0.004). Furthermore, the CUC showed a significant inverse correlation with TG, hemoglobin A1c (Hb A1c), homeostasis model assessment of insulin resistance (HOMA-IR), and body mass index (BMI). Finally, the HDL-C/Apolipoprotein A1 (ApoA1) ratio, calculated as a surrogate index of HDL particle size, was significantly positively correlated with the CUC (r2 = 0.49, P < 0.001), but inversely correlated with TG levels (r2 = -0.30, P < 0.001).

CONCLUSIONS

The CUC decreased in patients with hypertriglyceridemia and diabetes mellitus, and HDL particle size was a factor defining the CUC and inversely correlated with TG levels, suggesting that impaired CUC in insulin-resistant states was partially due to the shift in HDL towards smaller particles. These findings provide a better understanding of the mechanisms underlying impaired HDL functionality.

The Association of HDL2b with Metabolic Syndrome Among Normal HDL-C Populations in Southern China

Background

The annual prevalence of metabolic syndrome (MetS) is increasing. Therefore, early screening and recognition of MetS are critical. This study aimed to evaluate the association between high-density lipoprotein (HDL) subclasses and MetS and to examine whether they could serve as early indicators in a Chinese community-based population with normal high-density lipoprotein cholesterol (HDL-C) levels.

Methods

We used microfluidic chip technology to measure HDL subclasses in 463 people with normal HDL levels in 2018. We assessed how HDL subclasses correlated with and predicted insulin resistance (IR) and metabolic syndrome (MetS), evaluated by homeostatic model insulin resistance index (HOMA-IR) and the 2009 International Diabetes Federation (IDF), the American Heart Association (AHA), and the National Heart, Lung, and Blood Institute (NHLBI) criteria, respectively. We used correlation tests and ROC curves for the analysis.

Results

The results indicate that there was a negative association between HDL2b% and the risk of IR and MetS in both sexes. Subjects in the highest quartile of HDL2b% had a significantly lower prevalence of IR and MetS than those in the lowest quartile (P<0.01). Correlation analysis between HDL2b% and metabolic risk factors showed that HDL2b% had a stronger association with these factors than HDL-C did in both sexes. ROC curve analysis also showed that HDL2b% had significant diagnostic value for IR and MetS compared to other lipid indicators.

Conclusion

This study showed that MetS alters the distribution of HDL subclasses even when HDL-C levels are within the normal range. HDL-2b% has better diagnostic value for IR and MetS than HDL-C alone and may be a useful marker for early screening.

Stratification of hypertension and SARS-CoV-2 infection by quantitative NMR spectroscopy of human blood serum

BACKGROUND

Diagnostic approaches like the nuclear magnetic resonance spectroscopy (NMR) based quantification of metabolites, lipoproteins, and inflammation markers has helped to identify typical alterations in the blood serum of COVID-19 patients. However, confounders such as sex, and comorbidities, which strongly influence the metabolome, were often not considered. Therefore, the aim of this NMR study was to consider sex, as well as arterial hypertension (AHT), when investigating COVID-19-positive serum samples in a large age-and sex matched cohort.

METHODS

NMR serum data from 329 COVID-19 patients were compared with 305 healthy controls. 134 COVID-19 patients were affected by AHT. These were analyzed together with NMR data from 58 hypertensives without COVID-19. In addition to metabolite, lipoprotein, and glycoprotein data from NMR, common laboratory parameters were considered. Sex was considered in detail for all comparisons.

RESULTS

Here, we show that several differences emerge from previous NMR COVID-19 studies when AHT is considered. Especially, the previously described triglyceride-rich lipoprotein profile is no longer observed in COVID-19 patients, nor an increase in ketone bodies. Further alterations are a decrease in glutamine, leucine, isoleucine, and lysine, citric acid, HDL-4 particles, and total cholesterol. Additionally, hypertensive COVID-19 patients show higher inflammatory NMR parameters than normotensive patients.

CONCLUSIONS

We present a more precise picture of COVID-19 blood serum parameters. Accordingly, considering sex and comorbidities should be included in future metabolomics studies for improved and refined patient stratification. Due to metabolic similarities with other viral infections, these results can be applied to other respiratory diseases in the future.

Adsorption of Acylhydroperoxy-Derivatives of Phospholipids from Biomembranes by Blood Plasma Lipoproteins

It has been established that acylhydroperoxy derivatives of phospholipids from oxidized rat liver mitochondria are captured predominantly by LDL particles but not by HDL during co-incubation with blood plasma lipoproteins, which refutes the previously suggested hypothesis about the involvement of HDL in the reverse transport of oxidized phospholipids and confirms the possibility of different mechanisms of lipohydroperoxide accumulation in LDL during oxidative stress.

Do PON1-Q192R and PON1-L55M polymorphisms modify the effects of hypoxic training on paraoxonase and arylesterase activity?

BACKGROUND

Low levels of antioxidant paraoxonase 1 (PON1) enzyme activity, PON1-Q192R polymorphism (a glutamine (Q) to arginine (R) substitution at position 192), PON1-L55M polymorphism (a leucine (L) to methionine (M) substitution at position 55), and oxidized low-density lipoprotein (oxLDL) are risk factors for coronary heart disease. Aerobic exercise improves PON1 activity, but the effects of hypoxic exercise are yet unclear. The aim of this study was to determine the effects of hypoxic underwater rugby training on PON1 activity and oxLDL levels and the role of the mentioned polymorphisms.

METHODS

Serum PON1 and arylesterase activities (ARE), PON1, PON3, and oxLDL protein levels (by using the enzyme-linked immunosorbent assays) were determined in an athletic group (42 trained male underwater rugby players; age = 21.7 ± 4.2 years, mean ± SD) and a control group (43 sedentary men; age = 23.9 ± 3.2 years). The polymorphisms were determined from genomic DNA samples.

RESULTS

PON1 activity (25.1%, p = 0.052), PON3 (p < 0.001), and oxLDL (p < 0.001) of the athletic group, including most genotype groups, were higher than those of the control group. In comparison to the controls, PON1 activity levels (p = 0.005) of the PON1-Q192R homozygote QQ genotype group and PON1 activity levels (30%, p = 0.116) of the PON1-L55M homozygote LL genotype group were higher, whereas ARE activity values of athletic R allele carrier (Rc = QR + RR) (p = 0.005) and LL group (p = 0.002) were lower than the control genotype groups related to their polymorphisms.

CONCLUSION

Hypoxic training can cause (1) significant oxidative stress, including oxLDL, and an antioxidant response (increase in PON1 activity and PON3), (2) differences in the activity of PON1 and ARE, which are modified by PON1-Q192R and PON1-L55M polymorphisms, respectively, and (3) improvements in PON1 activity of QQ and LL groups. However, hypoxic training can cause a disadvantage of LL and Rc groups for ARE.

1-2 Drinks Per Day Affect Lipoprotein Composition after 3 Weeks-Results from a Cross-Over Pilot Intervention Trial in Healthy Adults Using Nuclear Magnetic Resonance-Measured Lipoproteins and Apolipoproteins

Alcohol consumption ranging from 1−2 drinks/day associates with a lower risk of coronary heart disease in some studies. The underlying mechanisms are unclear. The Metabolic Imprints of Alcoholic Beverages (MetAl) trial aimed to explore the short-term effects of moderate alcohol consumption on cardiovascular biomarkers. A 2 × 3-week cross-over single-blinded intervention trial investigating the effect of 1−2 drinks/day (~12−24 g) compared with abstention on 1H Nuclear Magnetic Resonance-measured main lipoproteins and subfractions was performed in 26 healthy adults. Volunteers were classified as occasional or habitual drinkers based on their habitual alcohol intakes (<2 or ≥2 drinks/week). Compared with abstention, 1−2 drinks/day increased HDL2a-C (p = 0.004), HDL3-C (p = 0.008), and HDL non-significantly (p = 0.19). Total apoA1 and apoA1 in HDL and its subfractions increased (p < 0.05). Novel findings were a decreased apoB/apoA1 ratio (p = 0.02), and increased HDL2a phospholipid content (p = 0.04). In women alone, the results were similar but attenuated, and LDL-P decreased. Thus, changes in apoA1- and HDL-related biomarkers occur within weeks in moderate drinkers. Compared with abstention, 1−2 drinks/day increased total apoA1 more strongly than HDL-C and increased the cholesterol, apoA1, and phospholipid content of several HDL subfractions. Whether this provides a cardiovascular benefit requires further study. Clinicaltrials.gov: NCT03384147.

HDL AND ITS SUBPOPULATION (HDL2 AND HDL3) PROMOTE CHOLESTEROL TRANSPORTERS EXPRESSION AND ATTENUATES INFLAMMATION IN 3T3-L1 MATURE ADIPOCYTES INDUCED BY TUMOR NECROSIS FACTOR ALPHA

Obesity activates inflammation causing dysfunction of adipocytes. Increasing high-density lipoprotein (HDL) levels in obesity may be beneficial in overcoming this effect. However, not much data is available on the effects of HDL and its subpopulations in inflamed adipocytes. The objective of this study was to investigate the effects of total HDL (tHDL) and the comparison between its subpopulations (HDL2 & HDL3) on protein and gene expression of cholesterol transporters, inflammation, and adipokines in TNF-α stimulated 3T3-L1 mature adipocytes. TNFα alone had lower adiponectin and higher protein and gene expression of IL-6 and NF-ĸβ (p65) compared to unstimulated adipocytes and these effects were attenuated by HDLs especially HDL3 (in most of the biomarkers). HDL and its subpopulation had higher cholesterol transporters expression in 3T3-L1 mature adipocytes induced by TNF-α compared to unstimulated cells. Increment of cholesterol transporters expression by HDL leads to reduce secretion of inflammatory markers [IL-6 & NF-kB (p65)] and visfatin and increases adiponectin secretion in the inflamed mature adipocytes. HDL exhibits beyond its reverse cholesterol transporter property by exhibiting anti-inflammatory effects thru the deactivation of NF-ĸβ (p65). This may contribute to reducing the progression of obesity-related complications.

Association of lipid profile with obesity among breast cancer survivors: a cross-sectional study

Background

The role of lipid metabolism in obesity and cancer manifestations cannot be underestimated, but whether alterations in lipid metabolism can manipulate the vasculature to promote obesity among breast cancer (BC) survivors is yet to be clearly understood. This study quantified plasma lipid and particle sizes using high-throughput proton (¹H) nuclear magnetic resonance (NMR) and tested their associations with obesity among breast cancer (BC) survivors.

Methods

A total of 348 (225 premenopausal and 123 postmenopausal) BC survivors enrolled from five hospitals in Korea were included. We assessed thirty-four plasma lipid biomarkers using ¹H NMR, and obesity status was defined as a body mass index (BMI) of 25 kg/m² or greater. Generalized linear and logistic regression models were applied to estimate the least-square means of BMI (kg/m²) and odds ratio (OR)s of obesity, respectively, and the corresponding 95% confidence interval (CI)s across plasma lipid levels.

Results

Mean (SD) values of BMI was 23.3 (3.2) kg/m² and 90 (25.9%) had BMI of ≥ 25 kg/m². BMI levels increased with increasing total triglycerides (TG), TG in lipoproteins and very-low-density lipoprotein (VLDL) subfractions. However, BMI levels decreased with increasing tertiles of high-density lipoprotein (HDL)-cholesterol (C) and HDL particle size (HDL-p). Similar associations were observed in the logistic regression models. The increasing and decreasing BMI trends with TG and HDL profiles respectively were predominantly limited to premenopausal BC survivors.

Conclusions

Increasing levels of plasma total TG and TG in lipoproteins were associated with increasing levels of BMI among premenopausal BC survivors. High HDL-C levels and large HDL-p were inversely associated with obesity among premenopausal BC survivors. Due to the cross-sectional design of this study, longitudinal studies are necessary to examine the association between obesity and lipid profile among BC survivors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01674-2.

Foetal lipoprotein oxidation and preeclampsia

Preeclampsia (PE) is a multisystemic syndrome specific to pregnancy. Although PE is the leading cause of death from complications associated with pregnancy, its aetiology is still unknown. In PE, lipid metabolism is altered. When lipids are damaged, both the mother and the foetus may be at risk. Lipoproteins contain apolipoproteins, triacylglycerols, free and esterified cholesterol, and phospholipids, all of which are susceptible to oxidative stress when high levels of oxygen and nitrogen free radicals are present. Lipoperoxidation can occur in three stages: mild, moderate, and severe. In severe lipid damage, highly toxic products such as malondialdehyde (MDA) can be generated; under these conditions, low-density lipoprotein (LDL) proteins can be oxidized (oxLDL). oxLDL is a biomolecule that can affect the production of nitric oxide (NO), the main vasodilator derived from the endothelium. oxLDL can interfere with the transduction of the signals responsible for triggering the activation of endothelial nitric oxide synthase (eNOS), causing reduced vasodilation and endothelial dysfunction, which are the main characteristics of preeclampsia. The objective of the review was to analyse the information the current information about exists about the impact generated by the oxidation of LDL and HDL lipoproteins in neonates of women with preeclampsia and how these alterations can predispose the neonate to develop diseases in adulthood.

PE can cause foetal loss, intrauterine growth restriction, or developmental complications. Neonates of mothers with PE have a high risk of cardiovascular diseases, stroke, mental retardation, sensory deficiencies and an increased risk of developing metabolic diseases. PE not only affects the foetus, generating complications during pregnancy but also predisposes them to chronic diseases in adulthood.

The Role of High-Density Lipoprotein Cholesterol in 2022

PURPOSE OF THE REVIEW

High-density lipoproteins (HDL) are responsible for the transport in plasma of a large fraction of circulating lipids, in part from tissue mobilization. The evaluation of HDL-associated cholesterol (HDL-C) has provided a standard method for assessing cardiovascular (CV) risk, as supported by many contributions on the mechanism of this arterial benefit. The present review article will attempt to investigate novel findings on the role and mechanism of HDL in CV risk determination.

RECENT FINDINGS

The most recent research has been aimed to the understanding of how a raised functional capacity of HDL, rather than elevated levels per se, may be responsible for the postulated CV protection. Markedly elevated HDL-C levels appear instead to be associated to a raised coronary risk, indicative of a U-shaped relationship. While HDL-C reduction is definitely related to a raised CV risk, HDL-C elevations may be linked to non-vascular diseases, such as age-related macular disease. The description of anti-inflammatory, anti-oxidative and anti-infectious properties has indicated potential newer areas for diagnostic and therapeutic approaches. In the last two decades inconclusive data have arisen from clinical trials attempting to increase HDL-C pharmacologically or by way of recombinant protein infusions (most frequently with the mutant A-I _Milano); prevention of stent occlusion or heart failure treatment have shown instead significant promise. Targeted clinical studies are still ongoing.

The Effects of Acute and Chronic Exercise on Paraoxonase-1 (PON1): A Systematic Review With Meta-Analysis

Purpose: To determine the acute and chronic effects of exercise on Paraoxonase-1 (PON1) concentration and activity. Methods: A literature search was performed using 16 electronic databases. Effect sizes (ES) were computed and two-tailed α values < .05 and non-overlapping 95% confidence intervals (95%CI) were considered statistically significant. Heterogeneity, inconsistency (I²), and small-study effects using the LFK index were examined. Results: Eighteen studies (n = 377 participants) met the criteria for inclusion. The acute effects of exercise on PON1 concentration were trivial and non-significant (ES = -.03, 95%CI = -.39 to .34, p > .05), heterogeneous (p = .05), moderately inconsistent (I² = 48%), with minor asymmetry (LFK index = 1.34). The chronic effects of exercise on PON1 concentration were also trivial and non-significant (ES = -.04, 95%CI = -.53 to.45, p > .05), homogenous (p = .65), displayed low inconsistency (I² = 0%), and minor asymmetry (LFK index = -1.14). The acute effects of exercise on PON1 activity were trivial and non-significant (ES = .11, 95%CI = -.02 to.24, p > .05), homogenous (p = .85), showed low inconsistency (I² = 0%), and no asymmetry (LFK index = .82). The chronic effects of exercise on PON1 activity were trivial and non-significant (ES = .31, 95%CI = -.03 to.65, p > .05), homogenous (p = .17), moderately inconsistent (I² = 36%), with no asymmetry (LFK index = .60). Conclusion: Acute and chronic exercise training, overall, exerted a trivial effect on PON1 concentration and activity.

Phytonutrients of Bitter Apricot Seeds Modulate Human Lipid Profile and LDL Subfractions in Adults with Elevated Cholesterol Levels

The objective of the present study was to evaluate the effect of short-term consumption of bitter apricot seeds phytonutrients on cardiovascular risk factors with a special focus on LDL cholesterol subfractions using the Lipoprint system. A group of 34 adult volunteers (21 female/13 male) consumed 60 mg kg⁻¹ of body weight of bitter apricot seeds daily for 42 days. Subjects were divided into two groups: one with normal cholesterol levels (NTC) and one with elevated total cholesterol levels (ETC). Blood serum levels of total cholesterol (T-C), low-density cholesterol (LDL-C), high-density cholesterol (HDL-C), and triglycerides (TG) did not change significantly (p > 0.05) in NTC group. However, there were significant decreasing of T-C (p ˂ 0.05) and LDL-C (p < 0.01) in ETC group. The LDL₁, LDL₂, and atherogenic LDL₃₋₇ subfractions progressively decreased after 42 days of apricot seeds consumption in ETC group (p < 0.05). Apricot seeds consumption was associated with a significant increase in the mean LDL particle size especially in ETC group (p ˂ 0.01). The results of the present study support the hypothesis that daily consumption of bitter apricot seeds for 42 days positively modified the lipoprotein profile in the group with elevated total cholesterol.

The value of HDL subfractions in predicting cardiovascular outcomes in untreated, diabetic patients with stable coronary artery disease: An age- and gender-matched case-control study

OBJECTIVE

The aim of the present study was to examine the value of high-density lipoprotein (HDL) subfractions for predicting cardiovascular events (CVEs) in untreated type 2 diabetes mellitus (T2DM) patients with stable coronary artery disease (SCAD) using an age- and gender-matched case-control study.

METHODS

In total, 185 SCAD patients and 185 T2DM patients with SCAD were enrolled and subjected to a clinical follow-up of CVEs. HDL subfractions were analyzed using the Quantimetrix Lipoprint System. The relationship between HDL subfractions and CVEs in T2DM patients with SCAD was evaluated by Kaplan-Meier analysis and Cox proportional hazard models.

RESULTS

During a median 37.7-month follow-up, T2DM patients with SCAD had a higher percentage of CVEs compared to SCAD patients (p=0.039). The concentration of the combined intermediate and small HDL-C subfraction (defined as the mixed HDL subfraction) was related to the event incidence in T2DM patients with SCAD (p=0.004), and it was positively associated with increased CVEs even after adjustment in three models. Kaplan-Meier curve analysis indicated that T2DM patients with SCAD in the high mixed HDL subfraction group (>28 mg/dL) had lower event-free survival rates (p=0.008).

CONCLUSIONS

Elevated concentration of the mixed HDL subfraction concentration predicts events in T2DM patients with SCAD.

Moderate alcohol consumption and lipoprotein subfractions: a systematic review of intervention and observational studies

CONTEXT

Moderate alcohol consumption is associated with decreased risk of cardiovascular disease (CVD) and improvement in cardiovascular risk markers, including lipoproteins and lipoprotein subfractions.

OBJECTIVE

To systematically review the relationship between moderate alcohol intake, lipoprotein subfractions, and related mechanisms.

DATA SOURCES

Following PRISMA, all human and ex vivo studies with an alcohol intake up to 60 g/d were included from 8 databases.

DATA EXTRACTION

A total of 17 478 studies were screened, and data were extracted from 37 intervention and 77 observational studies.

RESULTS

Alcohol intake was positively associated with all HDL subfractions. A few studies found lower levels of small LDLs, increased average LDL particle size, and nonlinear relationships to apolipoprotein B-containing lipoproteins. Cholesterol efflux capacity and paraoxonase activity were consistently increased. Several studies had unclear or high risk of bias, and heterogeneous laboratory methods restricted comparability between studies.

CONCLUSIONS

Up to 60 g/d alcohol can cause changes in lipoprotein subfractions and related mechanisms that could influence cardiovascular health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. 98955.

Malondialdehyde-modified HDL particles elicit a specific IgG response in abdominal aortic aneurysm

High Density Lipoprotein (HDL) plays a protective role in abdominal aortic aneurysm (AAA); however, recent findings suggest that oxidative modifications could lead to dysfunctional HDL in AAA. This study aimed at testing the effect of oxidized HDL on aortic lesions and humoral immune responses in a mouse model of AAA induced by elastase, and evaluating whether antibodies against modified HDL can be found in AAA patients. HDL particles were oxidized with malondialdehyde (HDL-MDA) and the changes were studied by biochemical and proteomics approaches. Experimental AAA was induced in mice by elastase perfusion and then mice were treated with HDL-MDA, HDL or vehicle for 14 days. Aortic lesions were studied by histomorphometric analysis. Levels of anti-HDL-MDA IgG antibodies were measured by an in-house immunoassay in the mouse model, in human tissue-supernatants and in plasma samples from the VIVA cohort. HDL oxidation with MDA was confirmed by enhanced susceptibility to diene formation. Proteomics demonstrated the presence of MDA adducts on Lysine residues of HDL proteins, mainly ApoA-I. MDA-modification of HDL abrogated the protective effect of HDL on cultured endothelial cells as well as on AAA dilation in mice. Exposure to HDL-MDA elicited an anti-HDL-MDA IgG response in mice. Anti-HDL-MDA were also detected in tissue-conditioned media from AAA patients, mainly in intraluminal thrombus. Higher plasma levels of anti-HDL-MDA IgG antibodies were found in AAA patients compared to controls. Anti-HDL-MDA levels were associated with smoking and were independent predictors of overall mortality in AAA patients. Overall, MDA-oxidized HDL trigger a specific humoral immune response in mice. Besides, antibodies against HDL-MDA can be detected in tissue and plasma of AAA patients, suggesting its potential use as surrogate stable biomarkers of oxidative stress in AAA.

Cardiac, Macro-, and Micro-Circulatory Abnormalities in Association With Individual Metabolic Syndrome Component: The Northern Shanghai Study

Objective: This study investigated the association of metabolic syndrome (MS) and its components with cardiac, macro-, and micro-circulatory abnormalities in an elderly Chinese population.

Methods: This cross-sectional study was conducted using data for 1,958 participants from the Northern Shanghai Study aged over 65 years without a history of cardiovascular disease. MS was defined according to the National Cholesterol Education Program Adult Treatment Panel III in 2005 (NCEPIII 2005). Asymptomatic cardiovascular impairment parameters, including the left ventricle mass index (LVMI), peak transmitral pulsed Doppler velocity/early diastolic tissue Doppler velocity (E/Ea), carotid-femoral pulse wave velocity (cf-PWV), ankle-brachial index (ABI), carotid intima-media thickness (CIMT), arterial plaque, and urinary albumin–creatinine rate (UACR), were evaluated.

Results: LVMI, E/Ea, cf-PWV, and the proportion of UACR > 30 mg/g exhibited increasing trends while ABI exhibited a decreasing trend according to the number of MS components (all p for trend < 0.01). Logistic regression analysis revealed that MS was significantly associated with LV hypertrophy (LVH), LV diastolic dysfunction, arteriosclerosis, and microalbuminuria (all p < 0.001). Central obesity and high blood pressure were associated with all cardiovascular abnormalities (all p < 0.05), whereas elevated plasma glucose was associated with arteriosclerosis and microalbuminuria (both p < 0.001). In addition, high triglyceride levels were associated with microalbuminuria (p < 0.05).

Conclusions: MS is significantly associated with cardiac, macro-, and micro-circulatory abnormalities in elderly Chinese. Moreover, the presence of individual MS components may have specific prognostic significance.

Extra Virgin Olive Oil Prevents the Age-Related Shifts of the Distribution of HDL Subclasses and Improves Their Functionality

High-density lipoproteins (HDL) maintain cholesterol homeostasis through the role they play in regulating reverse cholesterol transport (RCT), a process by which excess cholesterol is transported back to the liver for elimination. However, RCT can be altered in the presence of cardiovascular risk factors, such as aging, which contributes to the increase in the incidence of cardiovascular diseases (CVD). The present study was aimed at investigating the effect of extra virgin olive oil (EVOO) intake on the cholesterol efflux capacity (CEC) of HDL, and to elucidate on the mechanisms by which EVOO intake improves the anti-atherogenic activity of HDL. A total of 84 healthy women and men were enrolled and were distributed, according to age, into two groups: 27 young (31.81 ± 6.79 years) and 57 elderly (70.72 ± 5.6 years) subjects. The subjects in both groups were given 25 mL/d of extra virgin olive oil (EVOO) for 12 weeks. CEC was measured using J774 macrophages radiolabeled with tritiated cholesterol ((³H) cholesterol). HDL subclass distributions were analyzed using the Quantimetrix Lipoprint® system. The HDL from the elderly subjects exhibited a lower level of CEC, at 11.12% (p < 0.0001), than the HDL from the young subjects. The CEC of the elderly subjects returned to normal levels following 12 weeks of EVOO intake. An analysis of the distribution of HDL subclasses showed that HDL from the elderly subjects were composed of lower levels of large HDL (L-HDL) (p < 0.03) and higher levels of small HDL (S-HDL) (p < 0.002) compared to HDL from the young subjects. A multiple linear regression analysis revealed a positive correlation between CEC and L-HDL levels (r = 0.35 and p < 0.001) as well as an inverse correlation between CEC and S-HDL levels (r = −0.27 and p < 0.01). This correlation remained significant even when several variables, including age, sex, and BMI as well as low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and glucose levels (β = 0.28, p < 0.002, and β = 0.24, p = 0.01) were accounted for. Consuming EVOO for 12 weeks modulated the age-related difference in the distribution of HDL subclasses by reducing the level of S-HDL and increasing the level of intermediate-HDL/large-HDL (I-HDL/L-HDL) in the elderly subjects. The age-related alteration of the CEC of HDL was due, in part, to an alteration in the distribution of HDL subclasses. A diet enriched in EVOO improved the functionality of HDL through an increase in I-HDL/L-HDL and a decrease in S-HDL.

Long-term fasting improves lipoprotein-associated atherogenic risk in humans

Purpose

Dyslipidemia is a major health concern associated with an increased risk of cardiovascular mortality. Long-term fasting (LF) has been shown to improve plasma lipid profile. We performed an in-depth investigation of lipoprotein composition.

Methods

This observational study included 40 volunteers (50% men, aged 32–65 years), who underwent a medically supervised fast of 14 days (250 kcal/day). Changes in lipid and lipoprotein levels, as well as in lipoprotein subclasses and particles, were measured by ultracentrifugation and nuclear magnetic resonance (NMR) at baseline, and after 7 and 14 fasting days.

Results

The largest changes were found after 14 fasting days. There were significant reductions in triglycerides (TG, − 0.35 ± 0.1 mmol/L), very low-density lipoprotein (VLDL)-TG (− 0.46 ± 0.08 mmol/L), VLDL-cholesterol (VLDL-C, − 0.16 ± 0.03 mmol/L) and low-density lipoprotein (LDL)-C (− 0.72 ± 0.14 mmol/L). Analysis of LDL subclasses showed a significant decrease in LDL1-C (− 0.16 ± 0.05 mmol/L), LDL2-C (− 0.30 ± 0.06 mmol/L) and LDL3-C (− 0.27 ± 0.05 mmol/L). NMR spectroscopy showed a significant reduction in large VLDL particles (− 5.18 ± 1.26 nmol/L), as well as large (− 244.13 ± 39.45 nmol/L) and small LDL particles (− 38.45 ± 44.04 nmol/L). A significant decrease in high-density lipoprotein (HDL)-C (− 0.16 ± 0.04 mmol/L) was observed. By contrast, the concentration in large HDL particles was significantly raised. Apolipoprotein A1 decreased significantly whereas apolipoprotein B, lipoprotein(a), fibrinogen and high-sensitivity C-reactive protein were unchanged.

Conclusion

Our results suggest that LF improves lipoprotein levels and lipoprotein subclasses and ameliorates the lipoprotein-associated atherogenic risk profile, suggesting a reduction in the cardiovascular risk linked to dyslipidemia.

Trial Registration

Study registration number: DRKS-ID: DRKS00010111 Date of registration: 03/06/2016 “retrospectively registered”.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02578-0.

Association of Coronary Calcium, Carotid Wall Thickness, and Carotid Plaque Progression With Low-Density Lipoprotein and High-Density Lipoprotein Particle Concentration Measured by Ion Mobility (From Multiethnic Study of Atherosclerosis [MESA])

Current risk stratification strategies do not fully explain cardiovascular disease (CVD) risk. We aimed to evaluate the association of low-density lipoprotein (LDL-P) and high-density lipoprotein (HDL-P) particles with progression of coronary artery calcium and carotid wall injury. All participants in the Multi-Ethnic Study Atherosclerosis (MESA) with LDL-P and HDL-P measured by ion mobility, coronary artery calcium score (CAC), carotid intima-media thickness (IMT), and carotid plaque data available at Exam 1 and 5 were included in the study. CAC progression was annualized and treated as a categorical or continuous variable. Carotid IMT and plaque progression were treated as continuous variables. Fully adjusted regression models included established CVD risk factors, as well as traditional lipids. Mean (±SD) follow-up duration was 9.6 ± 0.6 years. All LDL-P subclasses as well as large HDL-P at baseline were positively and significantly associated with annualized CAC progression, however, after adjustment for established risk factors and traditional lipids, only the association with medium and very small LDL-P remained significant (β -0.02, p = 0.019 and β 0.01, p = 0.003, per 1 nmol/l increase, respectively). Carotid plaque score progression was positively associated with small and very small LDL-P (p <0.01 for all) and non-HDL-P (p = 0.013). Only the association with very small LDL-P remained significant in a fully adjusted model (p = 0.035). Mean IMT progression was not associated with any of the lipid particles. In conclusion, in the MESA cohort, LDL-P measured by ion mobility was significantly associated with CAC progression as well as carotid plaque progression beyond the effect of traditional lipids.

HDL Subclass Analysis in Predicting Metabolic Syndrome in Koreans With High HDL Cholesterol Levels

Background

High-density lipoprotein cholesterol (HDL-C) is a complex mixture of subclasses with heterogeneous atheroprotective activities. We analyzed HDL-C subclass in relation to cardiovascular risk and metabolic syndrome (MetS) in a population with high HDL-C levels.

Methods

A total of 300 Korean individuals with high HDL-C levels (≥2.331 mmol/L) were enrolled following a comprehensive general medical examination including body composition analysis. HDL3-C levels were measured using the HDL3-EX SEIKEN kit (Randox Ltd., Crumlin, UK) and non-HDL3-C levels were calculated by subtracting HDL3-C levels from total HDL-C levels.

Results

HDL3-C levels and HDL3-C proportion had a weak positive correlation with low-density lipoprotein cholesterol (LDL-C) and triglycerides (r=0.21, r=0.25; r=0.26, r=0.34, respectively, all P<0.001); in contrast, non-HDL3-C levels had a weak negative correlation with these parameters (r=−0.17 and r=−0.25, respectively, both P<0.005). HDL3-C levels and HDL3-C proportion were significantly higher in the MetS group (N=8) than in the non-MetS group (0.71 vs 0.63 mmol/L, P=0.001; 29.7 vs 25.8%, P=0.001, respectively); these were the only predictors of MetS among the lipid variables (areas under the curves [AUC]=0.84 and 0.83, respectively, both P=0.001).

Conclusions

In populations with high HDL-C levels, HDL-C subclass may provide a greater amount of information on cardiovascular risk and MetS than HDL-C levels alone.

Perimenopausal transdermal estradiol replacement reduces serum HDL cholesterol efflux capacity but improves cardiovascular risk factors

BACKGROUND

The cardiovascular (CV) safety of estrogen replacement therapy (ERT) in perimenopausal women remains uncertain. Although exogenous estrogens increase HDL cholesterol (HDL-C), estrogen-mediated effects on alternative metrics of HDL that may better predict CV risk are unknown.

OBJECTIVE

To determine the effects of transdermal ERT on HDL composition and cholesterol efflux capacity (CEC), as well as the relationships between these metrics and CV risk factors.

METHODS

Fasting plasma samples were analyzed from 101 healthy, perimenopausal women randomized to receive either transdermal placebo or transdermal estradiol (100 μg/24 h) with intermittent micronized progesterone. At baseline and after 6 months of treatment, serum HDL CEC, HDL particle concentration, HDL protein composition, insulin resistance and brachial artery flow-mediated dilatation (FMD) were measured.

RESULTS

No difference between groups was found for change in plasma HDL-C (p = 0.69). Between-group differences were found for changes in serum HDL total CEC [median change from baseline -5.4 (-17.3,+8.4)% ERT group versus +5.8 (-6.3,+16.9)% placebo group, p = 0.01] and ABCA1-specific CEC [median change from baseline -5.3 (-10.7,+6.7)% ERT group versus +7.4 (-1.5,+18.1)% placebo group, p = 0.0002]. Relative to placebo, transdermal ERT led to reductions in LDL-C (p < 0.0001) and insulin resistance (p = 0.0002). An inverse correlation was found between changes in serum HDL total CEC and FMD (β = -0.26, p = 0.004).

CONCLUSIONS

Natural menopause leads to an increase in serum HDL CEC, an effect that is abrogated by transdermal ERT. However, transdermal ERT leads to favorable changes in major CV risk factors.

A homogeneous assay to determine high-density lipoprotein subclass cholesterol in serum

Existing methods to measure high-density lipoprotein cholesterol (HDL-C) subclasses (HDL₂-C and HDL₃-C) are complex and require proficiency, and thus there is a need for a convenient, homogeneous assay to determine HDL-C subclasses in serum. Here, cholesterol reactivities in lipoprotein fractions [HDL₂, HDL₃, low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL)] toward polyethylene glycol (PEG)-modified enzymes were determined in the presence of varying concentrations of dextran sulfate and magnesium nitrate. Particle sizes formed in the lipoprotein fractions were measured by dynamic light scattering. We optimized the concentrations of dextran sulfate and magnesium nitrate before assay with PEG-modified enzymes to provide selectivity for HDL₃-C. On addition of dextran sulfate and magnesium nitrate, the sizes of particles of HDL₂, LDL, and VLDL increased, but the size of HDL₃ fraction particles remained constant, allowing only HDL₃-C to participate in coupled reactions with the PEG-modified enzymes. In serum from both healthy volunteers and patients with type 2 diabetes, a good correlation was observed between the proposed assay and ultracentrifugation in the determination of HDL-C subclasses. The assay proposed here enables convenient and accurate determination of HDL-C subclasses in serum on a general automatic analyzer and enables low-cost routine diagnosis without preprocessing.

High-density lipoprotein characteristics and coronary artery disease: a Mendelian randomization study

BACKGROUND

To assess whether genetically determined quantitative and qualitative HDL characteristics were independently associated with coronary artery disease (CAD).

METHODS

We designed a two-sample multivariate Mendelian randomization study with available genome-wide association summary data. We identified genetic variants associated with HDL cholesterol and apolipoprotein A-I levels, HDL size, particle levels, and lipid content to define our genetic instrumental variables in one sample (Kettunen et al. study, n = 24,925) and analyzed their association with CAD risk in a different study (CARDIoGRAMplusC4D, n = 184,305). We validated these results by defining our genetic variables in another database (METSIM, n = 8372) and studied their relationship with CAD in the CARDIoGRAMplusC4D dataset. To estimate the effect size of the associations of interest adjusted for other lipoprotein traits and minimize potential pleiotropy, we used the Multi-trait-based Conditional & Joint analysis.

RESULTS

Genetically determined HDL cholesterol and apolipoprotein A-I levels were not associated with CAD. HDL mean diameter (β = 0.27 [95%CI = 0.19; 0.35]), cholesterol levels in very large HDLs (β = 0.29 [95%CI = 0.17; 0.40]), and triglyceride content in very large HDLs (β = 0.14 [95%CI = 0.040; 0.25]) were directly associated with CAD risk, whereas the cholesterol content in medium-sized HDLs (β = -0.076 [95%CI = -0.10; -0.052]) was inversely related to this risk. These results were validated in the METSIM-CARDIoGRAMplusC4D data.

CONCLUSIONS

Some qualitative HDL characteristics (related to size, particle distribution, and cholesterol and triglyceride content) are related to CAD risk while HDL cholesterol levels are not.

Evolocumab Effects on Lipoproteins, Measured by High-Performance Liquid Chromatography

AIMS

Profiling of lipoproteins can predict risk of cardiovascular disease; gel permeation high-performance liquid chromatography (HPLC) improves prediction accuracy by providing detailed data for specific lipoprotein subclasses. This study applied HPLC to examine the effects of evolocumab, which effectively treats hyperlipidemia and mixed dyslipidemia, on lipoprotein subclasses, specifically the number and size of lipoprotein particles.

METHODS

This post-hoc analysis used patient blood samples from YUKAWA-2, a phase 3 trial evaluating the efficacy of evolocumab in Japanese adult patients with hyperlipidemia or mixed dyslipidemia and at high risk for cardiovascular disease. We used HPLC to assess observed values and percent change from baseline in cholesterol and triglyceride (TG) concentrations, number of particles in lipoprotein subclasses to week 12, and mean observed values and mean percent change from baseline in variables to weeks 10 and 12. HPLC was also compared with conventional methods in assessing low-density lipoprotein (LDL) cholesterol (LDL-C) values.

RESULTS

Data for all 404 patients were analyzed. Evolocumab significantly decreased cholesterol and TG concentrations, and total particle count, in very low-density lipoprotein (VLDL) and LDL subclasses. Particle size increased slightly in LDL, high-density lipoprotein (HDL), and VLDL, but data varied widely. At very low LDL-C, HPLC measurements were higher than those from conventional methods.

CONCLUSION

This research used HPLC to assess the effects of evolocumab in 20 lipid subclasses. By lowering lipid content and improving the lipid profile, evolocumab may reduce atherogenicity. This reduction is better quantified by HPLC than by conventional methods in the very low LDL-C range.

Cardiovascular Risk Factor Reduction in First Responders Resulting From an Individualized Lifestyle and Blood Test Program: A Randomized Controlled Trial

OBJECTIVE

We tested the hypothesis that a lifestyle program would improve risk factors linked to cardiovascular disease (CVD) in first responders.

METHODS

A 1-year cluster-randomized controlled clinical trial in 10 cities. Participants were 175 first responders, with increased waist circumference and/or low levels of large (α1) high-density lipoprotein (HDL) particles. The intervention group received personalized online tools and access to telephonic coaching sessions.

RESULTS

At 1 year the intervention significantly reduced body weight (P = 0.004) and waist circumference (P = 0.002), increased α1 HDL (P = 0.01), and decreased triglyceride (P = 0.005) and insulin concentrations (P = 0.03). Program adherence was associated with weight loss (P = 0.0005) and increases in α1 HDL (P = 0.03).

CONCLUSIONS

In first responders, a personalized lifestyle intervention significantly improved CVD risk factors in proportion to program adherence. Changes in large HDL particles were more sensitive indicators of lifestyle changes than HDL-cholesterol measurement.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT03322046.

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.

Genetic determinants of blood lipids and cerebral small vessel disease: role of high-density lipoprotein cholesterol

Blood lipids are causally involved in the pathogenesis of atherosclerosis, but their role in cerebral small vessel disease remains largely elusive. Here, we explored associations of genetic determinants of blood lipid levels, lipoprotein particle components, and targets for lipid-modifying drugs with small vessel disease phenotypes. We selected genetic instruments for blood levels of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides, for cholesterol and triglycerides components of size-defined lipoprotein particles, and for lipid-modifying drug targets based on published genome-wide association studies (up to 617 303 individuals). Applying two-sample Mendelian randomization approaches we investigated associations with ischaemic and haemorrhagic manifestations of small vessel disease [small vessel stroke: 11 710 cases, 287 067 controls; white matter hyperintensities (WMH): 10 597 individuals; intracerebral haemorrhage: 1545 cases, 1481 controls]. We applied the inverse-variance weighted method and multivariable Mendelian randomization as our main analytical approaches. Genetic predisposition to higher HDL-C levels was associated with lower risk of small vessel stroke [odds ratio (OR) per standard deviation = 0.85, 95% confidence interval (CI) = 0.78-0.92] and lower WMH volume (β = -0.07, 95% CI = -0.12 to -0.02), which in multivariable Mendelian randomization remained stable after adjustments for LDL-C and triglycerides. In analyses of lipoprotein particle components by size, we found these effects to be specific for cholesterol concentration in medium-sized high-density lipoprotein, and not large or extra-large high-density lipoprotein particles. Association estimates for intracerebral haemorrhage were negatively correlated with those for small vessel stroke and WMH volume across all lipid traits and lipoprotein particle components. HDL-C raising genetic variants in the gene locus of the target of CETP inhibitors were associated with lower risk of small vessel stroke (OR: 0.82, 95% CI = 0.75-0.89) and lower WMH volume (β = -0.08, 95% CI = -0.13 to -0.02), but a higher risk of intracerebral haemorrhage (OR: 1.64, 95% CI = 1.26-2.13). Genetic predisposition to higher HDL-C, specifically to cholesterol in medium-sized high-density lipoprotein particles, is associated with both a lower risk of small vessel stroke and lower WMH volume. These analyses indicate that HDL-C raising strategies could be considered for the prevention of ischaemic small vessel disease but the net benefit of such an approach would need to be tested in a randomized controlled trial.

Increased Oxidized High-Density Lipoprotein/High-Density Lipoprotein-Cholesterol Ratio as a Potential Indicator of Disturbed Metabolic Health in Overweight and Obese Individuals

BACKGROUND

We evaluated the qualitative characteristics of high-density lipoprotein (HDL) particles in metabolically healthy and unhealthy overweight and obese subjects.

METHODS

The study involved 115 subject individuals classified as metabolically healthy and unhealthy, as in overweight and obese groups. Commercial enzyme-linked immunosorbent assay (ELISA) kits were used to measure oxidized HDL (OxHDL) and serum amyloid A (SAA) concentrations. Lipoprotein subfractions were separated using nondenaturing gradient gel electrophoresis.

RESULTS

An independent association was shown between increased OxHDL/HDL-cholesterol ratio and the occurrence of metabolically unhealthy phenotype in the overweight and obese groups. The OxHDL/HDL-cholesterol ratio showed excellent and acceptable diagnostic accuracy in determination of metabolic health phenotypes (overweight group, AUC = 0.881; obese group, AUC = 0.765). Accumulation of smaller HDL particles in metabolically unhealthy subjects was verified by lipoprotein subfraction analysis. SAA concentrations did not differ significantly between phenotypes.

CONCLUSIONS

Increased OxHDL/HDL-cholesterol ratio may be a potential indicator of disturbed metabolic health in overweight and obese individuals.

High-density lipoprotein cholesterol concentration and acute kidney injury after noncardiac surgery

Background

Abnormal High-density Lipoprotein Cholesterol Concentration is closely related to postoperative acute kidney injury (AKI) after cardiac surgeries. The purpose of this study was to analyze the relationship between High-density Lipoprotein Cholesterol Concentration and acute kidney injury after non-cardiac surgeries.

Method

This was a single-center cohort study for elective non-cardiac non-kidney surgery from January 1, 2012, to December 31, 2017. The endpoint was the occurrence of acute kidney injury (AKI) 7 days postoperatively in the hospital. Preoperative serum High-density Lipoprotein Cholesterol Concentration was examined by multivariate logistic regression models before and after propensity score weighting analysis.

Results

Of the 74,284 surgeries, 4.4% (3159 cases) suffered acute kidney injury. The odds ratio for HDL (0.96–1.14 as reference, < 0.96, 1.14–1.35, > 1.35) was 1.28 (1.14–1.41), P < 0.001; 0.91 (0.80–1.03), P = 0.150; 0.75 (0.64–0.85), P < 0.001, respectively. Using a dichotomized cutoff point for propensity analysis, Preoperative serum HDL <  1.03 mmol/L (> 1.03 as reference) was associated with increased risk of postoperative AKI, with odds ratio 1.40 (1.27 ~ 1.52), P < 0.001 before propensity score weighting, and 1.32 (1.21–1.46), P < 0.001 after propensity score weighting. Sensitivity analysis with other cut values of HDL showed similar results.

Conclusions

Using multivariate regression analyses before and after propensity score weighting, in addition to multiple sensitivity analysis methods, this study found that following non-cardiac surgery, low HDL cholesterol levels were independent risk factors for AKI.

Lipoprotein profiling in early multiple sclerosis patients: effect of chronic inflammation?

Background

Inflammatory cytokines contribute to proatherogenic changes in lipid metabolism by reduction of HDL-cholesterol (HDL-C) levels, impairment of its antiinflammatory and antioxidant functions. Therefore, the protective actions of HDL-C can be limited in chronic inflammatory diseases such as multiple sclerosis (MS). The aim of this study was to assess the association between lipoprotein subfractions and inflammatory status in early stages of multiple sclerosis.

Methods

Polyacrylamide gel electrophoresis Lipoprint© System was used for lipoprotein profile analysis in 19 newly diagnosed MS patients, and in matched 19 healthy controls. Serum levels of interleukin (IL) 1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p70), IL-13, IL-17, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor, interferon-γ and TNF-α were measured by multiplex bead assay.

Results

Concentrations of the measured cytokines and lipoprotein subclasses were comparable between MS patients and controls. Male, but not female MS patients had significantly higher total HDL-C and small HDL-C subfraction than healthy controls. Large HDL-C negatively correlated with all measured cytokines except IL-17 in MS but not in controls. Intermediate HDL-C subfractions correlated positively with all measured cytokines except G-CSF in MS females but not in MS males or controls.

Conclusion

Our results of higher HDL-C and mainly its small HDL-C subfraction suggest that male MS patients are at higher risk of atherosclerosis and the subtle dyslipidemia is present in early stages of the disease. The correlations between specific HDL-C subfractions and the inflammatory cytokines demonstrate mutual links between systemic inflammation and lipid metabolism in MS.

Trial registration

ClinicalTrials.gov, Identifier: NCT 03052595 Registered on Feb 14, 2017.

Assessing Atherosclerotic Cardiovascular Disease Risk with Advanced Lipid Testing: State of the Science

Cardiovascular disease is the number one cause of death and disability worldwide. While substantial gains have been made in reducing cardiovascular mortality, future projections suggest that we have reached a nadir and may be at an inflection point, given the rising tide of obesity and diabetes. Evaluation and management of plasma lipids is central to the prevention of atherosclerotic cardiovascular disease. Although the standard lipid panel represents a well-established platform to assess risk, this test alone can be insufficient and/or misleading. Advances in our understanding of atherosclerosis have led to the development of lipid-based biomarkers that help to discriminate the risk of cardiovascular disease when it is unclear. While these biomarkers provide novel information, their implementation into clinical medicine remains difficult given discrepancies in the literature, lack of assay standardisation, poor accessibility and high cost. However, additional measures of atherogenic lipoproteins or their surrogates may offer insight beyond the standard lipid panel, providing a more precise assessment of risk and more accurate assessment of lipid-lowering therapy.

Structure-function relationships of HDL in diabetes and coronary heart disease

High-density lipoproteins (HDL) contain hundreds of lipid species and proteins and exert many potentially vasoprotective and antidiabetogenic activities on cells. To resolve structure-function-disease relationships of HDL, we characterized HDL of 51 healthy subjects and 98 patients with diabetes (T2DM), coronary heart disease (CHD), or both for protein and lipid composition, as well as functionality in 5 cell types. The integration of 40 clinical characteristics, 34 nuclear magnetic resonance (NMR) features, 182 proteins, 227 lipid species, and 12 functional read-outs by high-dimensional statistical modeling revealed, first, that CHD and T2DM are associated with different changes of HDL in size distribution, protein and lipid composition, and function. Second, different cellular functions of HDL are weakly correlated with each other and determined by different structural components. Cholesterol efflux capacity (CEC) was no proxy of other functions. Third, 3 potentially novel determinants of HDL function were identified and validated by the use of artificially reconstituted HDL, namely the sphingadienine-based sphingomyelin SM 42:3 and glycosylphosphatidylinositol-phospholipase D1 for the ability of HDL to inhibit starvation-induced apoptosis of human aortic endothelial cells and apolipoprotein F for the ability of HDL to promote maximal respiration of brown adipocytes.

Effect of 8-weeks intensive lifestyle intervention on LDL and HDL subfractions

OBJECTIVE

Atherogenic dyslipidemia is a cardinal feature of obesity and the metabolic syndrome, which increases the risk of cardiovascular diseases. Many interventional studies, describing the influence of weight loss on cardiometabolic risks, are bariatric surgery studies. The aim of our study was to analyze the effect of intensive lifestyle changes on LDL- and HDL-cholesterol subfractions and cardiometabolic risk factors in obese subjects.

METHODS

A group of 41 patients with obesity (11M/30F; 44.1±12.4 years; BMI 30.2±6.3kg/m²) participated in an 8-week weight loss interventional program (NCT02325804), consisting of caloric intake reduced by 30% and physical activity (150min/week). Insulin sensitivity was evaluated according to the homeostasis model assessment of insulin resistance (HOMA-IR) and physical fitness was measured using bicycle ergometry. Lipid subfractions were measured using the Lipoprint system (Quantimetrix Corp., CA, USA).

RESULTS

After the intervention, body weight was reduced by 5.4±4.5kg, as well as body fat mass and waist circumference. Physical fitness improved, systolic and diastolic blood pressure as well as heart rate decreased after the intervention. Insulin sensitivity improved after the intervention. Total, LDL, HDL cholesterol, as well as triglycerides decreased after the intervention. Regarding the lipoprotein subfractions, LDL2 and small HDL subfractions decreased, while others have not changed.

CONCLUSION

Eight weeks of diet and physical activity intervention led to weight and fat mass loss and induced improvement of insulin sensitivity, as well as atheroprotective changes of lipid profile. However, the weight loss associated changes in cholesterol subfractions as cardiovascular risk biomarkers deserve further studies.

Comparing Data-Independent Acquisition and Parallel Reaction Monitoring in Their Abilities To Differentiate High-Density Lipoprotein Subclasses

High-density lipoprotein (HDL) is a diverse group of particles with multiple cardioprotective functions. HDL proteome follows HDL particle complexity. Many proteins were described in HDL, but consistent quantification of HDL protein cargo is still a challenge. To address this issue, the aim of this work was to compare data-independent acquisition (DIA) and parallel reaction monitoring (PRM) methodologies in their abilities to differentiate HDL subclasses through their proteomes. To this end, we first evaluated the analytical performances of DIA and PRM using labeled peptides in pooled digested HDL as a biological matrix. Next, we compared the quantification capabilities of the two methodologies for 24 proteins found in HDL₂ and HDL₃ from 19 apparently healthy subjects. DIA and PRM exhibited comparable linearity, accuracy, and precision. Moreover, both methodologies worked equally well, differentiating HDL subclasses' proteomes with high precision. Our findings may help to understand HDL functional diversity.

Two-Hour Postprandial Lipoprotein Particle Concentration Differs Between Lean and Obese Individuals

The concentrations of lipoprotein particles [high-density lipoproteins (HDLs), low-density lipoproteins (LDLs), very-low-density lipoproteins (VLDLs), and chylomicrons] are associated with the risk of cardiovascular diseases. Most studies have examined these associations in the fasting state. Previous studies have shown lipoprotein particle concentration change following meal, and these changes are different in individuals with obesity. In this study, we aimed to assess whether various meal compositions lead to adverse short-term (2-h) postprandial lipoproteinemia in obese insulin resistant (obese-IR) subjects as compared to lean insulin sensitive (lean-IS) subjects. In a randomized crossover trial, nine lean-IS and nine obese-IR Chinese men aged 22–35 years were challenged with isoenergetic and isovolumic meals rich in protein (HP), fat (HF), or carbohydrate (HC). Plasma samples were collected after a 10-h fast, as well as 1-h and 2-h post-meal and analyzed using nuclear magnetic resonance. Plasma concentration of large VLDLs and chylomicron particles was higher and increased more after all meals in obese-IR compared to lean-IS subjects. The HP meal decreased small LDL particle concentration in obese-IR subjects, and increased small HDL particle concentration in all subjects. The HF meal led to a decrease in small HDL concentration in all subjects. In conclusion, obese-IR subjects revealed a detrimental response to meal challenges even as early as 2-h after meal intake.

Relation of oxidized-low-density lipoprotein and high-density lipoprotein subfractions in non-treated patients with coronary artery disease

BACKGROUND

Oxidized-low-density lipoprotein (ox-LDL), as well as high-density lipoprotein (HDL) and its subfractions play important role in the development of coronary artery disease (CAD).

METHODS

A total of 1417 individuals who received selective coronary angiography (CAG) without lipids-lowering treatments were consecutively enrolled. Patients were divided into CAD (n = 942) and non-CAD group (n = 475). The severity of CAD was assessed by Gensini Scores (GS) system. The correlations of ox-LDL with HDL subfractions were analyzed.

RESULTS

Compared with non-CAD subjects, CAD patients had higher ox-LDL but lower concentrations of HDL cholesterol (p = 0.002) and large HDL subfractions (p = 0.004). And ox-LDL was negatively correlated with large HDL subfractions in patients with severe CAD (p < 0.05). Moreover, ox-LDL was elevated and large HDL subfractions decreased with the increase of the number of stenotic coronary arteries and GS (p < 0.05, respectivelly).

CONCLUSIONS

The correlations between ox-LDL and cholesterol level of large HDL particles varied among CAD and non-CAD, and CAD with different severities of atherosclerosis.

Optimal Dietary Ferulic Acid for Suppressing the Obesity-Related Disorders in Leptin-Deficient Obese C57BL/6J -ob/ob Mice

Ferulic acid (FA) is a major polyphenolic compound and has been shown to improve the glucose and lipid homeostasis in high-fat diet-induced obese mice. Here, we found the optimal level of dietary FA to ameliorate obesity and obesity-correlated disorders, and identified the responses of gut microbiota to dietary FA in genetic leptin-deficient obese ( ob/ob) mice. The ob/ob mice exhibited persistent higher body weights, feed efficiency, white adipose tissue weights, and hepatic lipid accumulation, compared to those of the wild-type mice. However, 0.5% dietary FA suppressed these symptoms in ob/ob mice. The diversity of gut microbiota and the total abundance of obesity- and anti-obesity-related genera were not influenced after FA intervention in ob/ob mice. These data suggest that sufficient intake of FA (0.5%) could be useful for treating obesity or obesity-related diseases, and this weight-control effect is possibly not correlated with the gut-brain axis.

The effect of apolipoprotein E polymorphism on serum metabolome - a population-based 10-year follow-up study

Apolipoprotein E (apoE) is the key regulator of plasma lipids, mediating altered functionalities in lipoprotein metabolism - affecting the risk of coronary artery (CAD) and Alzheimer's diseases, as well as longevity. Searching pathways influenced by apoE prior to adverse manifestations, we utilized a metabolome dataset of 228 nuclear-magnetic-resonance-measured serum parameters with a 10-year follow-up from the population-based Young Finns Study cohort of 2,234 apoE-genotyped (rs7412, rs429358) adults, aged 24-39 at baseline. At the end of our follow-up, by limiting FDR-corrected p < 0.05, regression analyses revealed 180/228 apoE-polymorphism-related associations with the studied metabolites, in all subjects - without indications of apoE x sex interactions. Across all measured apoE- and apoB-containing lipoproteins, ε4 allele had consistently atherogenic and ε2 protective effect on particle concentrations of free/esterified cholesterol, triglycerides, phospholipids and total lipids. As novel findings, ε4 associated with glycoprotein acetyls, LDL-diameter and isoleucine - all reported biomarkers of CAD-risk, inflammation, diabetes and total mortality. ApoE-subgroup differences persisted through our 10-year follow-up, although some variation of individual metabolite levels was noticed. In conclusion, apoE polymorphism associate with a complex metabolic change, including aberrations in multiple novel biomarkers related to elevated cardiometabolic and all-cause mortality risk, extending our understanding about the role of apoE in health and disease.

Current Therapies Focused on High-Density Lipoproteins Associated with Cardiovascular Disease

High-density lipoproteins (HDL) comprise a heterogeneous family of lipoprotein particles divided into subclasses that are determined by density, size and surface charge as well as protein composition. Epidemiological studies have suggested an inverse correlation between High-density lipoprotein-cholesterol (HDL-C) levels and the risk of cardiovascular diseases and atherosclerosis. HDLs promote reverse cholesterol transport (RCT) and have several atheroprotective functions such as anti-inflammation, anti-thrombosis, and anti-oxidation. HDLs are considered to be atheroprotective because they are associated in serum with paraoxonases (PONs) which protect HDL from oxidation. Polyphenol consumption reduces the risk of chronic diseases in humans. Polyphenols increase the binding of HDL to PON1, increasing the catalytic activity of PON1. This review summarizes the evidence currently available regarding pharmacological and alternative treatments aimed at improving the functionality of HDL-C. Information on the effectiveness of the treatments has contributed to the understanding of the molecular mechanisms that regulate plasma levels of HDL-C, thereby promoting the development of more effective treatment of cardiovascular diseases. For that purpose, Scopus and Medline databases were searched to identify the publications investigating the impact of current therapies focused on high-density lipoproteins.

Statin Effects on Metabolic Profiles: Data From the PREVEND IT (Prevention of Renal and Vascular End-stage Disease Intervention Trial)

BACKGROUND

Statins lower cholesterol by inhibiting HMG-CoA reductase, the rate-limiting enzyme of the metabolic pathway that produces cholesterol and other isoprenoids. Little is known about their effects on metabolite and lipoprotein subclass profiles. We, therefore, investigated the molecular changes associated with pravastatin treatment compared with placebo administration using a nuclear magnetic resonance-based metabolomics platform.

METHODS AND RESULTS

We performed metabolic profiling of 231 lipoprotein and metabolite measures in the PREVEND IT (Prevention of Renal and Vascular End-stage Disease Intervention Trial) study, a placebo-controlled randomized clinical trial designed to test the effects of pravastatin (40 mg once daily) on cardiovascular risk. Metabolic profiles were assessed at baseline and after 3 months of treatment. Pravastatin lowered low-density lipoprotein cholesterol (change in SD units [95% confidence interval]: -1.01 [-1.14, -0.88]), remnant cholesterol (change in SD units [95% confidence interval]: -1.03 [-1.17, -0.89]), and apolipoprotein B (change in SD units [95% confidence interval]: -0.98 [-1.11, -0.86]) with similar effect magnitudes. In addition, pravastatin globally lowered levels of lipoprotein subclasses, with the exception of high-density lipoprotein subclasses, which displayed a more heterogeneous response pattern. The lipid-lowering effect of pravastatin was accompanied by selective changes in lipid composition, particularly in the cholesterol content of very-low-density lipoproteinparticles. In addition, pravastatin reduced levels of several fatty acids but had limited effects on fatty acid ratios.

CONCLUSIONS

These randomized clinical trial data demonstrate the widespread effects of pravastatin treatment on lipoprotein subclass profiles and fatty acids.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT03073018.

Influence of high density lipoprotein cholesterol levels on circulating monocytic angiogenic cells functions in individuals with type 2 diabetes mellitus

Background

High-density lipoproteins (HDLs) can exert anti-atherogenic effects. On top of removing excess cholesterol through reverse cholesterol transport, HDLs play beneficial actions on endothelial function and integrity. In particular, HDLs are strong determinant of endothelial progenitor cells (EPCs) number and function. To gain further insights into such an effect we characterized in vitro functionality of circulating “early” EPCs obtained from 60 type 2 diabetes individuals with low HDL-cholesterol (HDL-C) and 59 with high HDL-C levels.

Methods

After an overnight fast, venous blood was drawn in EDTA tubes and processed within 2-h from sampling. Peripheral blood mononuclear cells were isolated and plated on fibronectin coated culture dishes; after 3 days culture, adherent cells positive for Dil-ac-LDL/Lectin dual fluorescent staining were identified as monocytic angiogenic cells (MACs). After 5–7 days culture in EBM-2 medium, adherent cells were evaluated for viability/proliferation (MTT assay), senescence (beta-galactosidase activity detection), migration (modified Boyden chamber using VEGF as chemoattractant), adhesion capacity (on fibronectin-coated culture dishes) and ROS production (ROS-sensitive fluorescent probe CM-H₂DCFDA).

Results

MACs obtained from diabetic individuals with high HDL-C had 23% higher viability compared to low HDL-C (111.6 ± 32.7% vs. 90.5 ± 28.6% optical density; p = 0.002). H₂O₂ exposure impaired MACs viability to a similar extent in both groups (109.2 ± 31.7% vs. 74.5 ± 40.8% in high HDL-C, p < 0.0001; 88.3 ± 25.5% vs. 72.3 ± 22.5% in low-HDL, p = 0.004). MACs senescence was comparable in the two groups (102.7 ± 29.8% vs. 99.2 ± 27.8%; p = 0.703) and was only slightly modified by exposure to H₂O₂. There was no difference in the MACs migration capacity between the two groups (91.3 ± 34.2% vs. 108.7 ± 39.5%; p = 0.111), as well as in MACs adhesion capacity (105.2 ± 32.7% vs. 94.1 ± 26.1%; p = 0.223). Finally, ROS production was slightly thought not significantly higher in MACs from type 2 diabetes individuals with low- than high-HDL. After stratification of HDL-C levels into quartiles, viability (p < 0.0001) and adhesion (p = 0.044) were higher in Q4 than in Q1–Q3. In logistic regression analysis, HDL-C was correlated to MACs viability and adhesion independently of HbA1c or BMI, respectively.

Conclusions

Our data suggest that in type 2 diabetes subjects, HDL-cholesterol is an independent determinant of circulating MACs functional capacities—mainly viability, to a lesser extent adhesion—likely contributing also through this mechanism to cardiovascular protection even in type 2 diabetes.

Association between high-density lipoprotein subfractions and low-grade inflammation, insulin resistance, and metabolic syndrome components: The ELSA-Brasil study

BACKGROUND

High-density lipoprotein cholesterol (HDL-C) can be divided into subfractions, which may have variable effects in atherogenesis. The results about the association between HDL-C subfractions and risk factors for cardiovascular disease are mixed.

OBJECTIVE

The objective of this study was to analyze the association between HDL-C subfractions and each metabolic syndrome component, homeostasis model assessment-estimated insulin resistance (HOMA-IR) and C-reactive protein (CRP).

METHODS

Four thousand five hundred thirty-two individuals between 35 and 74 years old without previous manifest cardiovascular disease not using fibrates were enrolled. HDL-C subfractions were separated by vertical ultracentrifugation (vertical auto profile-in mg/dL) into HDL₂-C and HDL₃-C. HDL₂-C/HDL₃-C ratio, HOMA-IR, and high-sensitivity CRP were also included in the analysis.

RESULTS

Mean age of participants was 51 ± 9 years, and 54.8% were women. In univariate analysis, HDL-C, HDL₂-C, and HDL₃-C were all inversely associated with each of the metabolic syndrome defining factors, HOMA-IR values, and serum CRP. We also observed a negative association between HDL₂-C/HDL₃-C ratio with the variables aforementioned even after adjusting for smoking, alcohol use, physical activity, and HDL-C levels (P < .01).

CONCLUSION

HDL-C and its subfractions (HDL₂-C and HDL₃-C) are inversely associated with the defining features of metabolic syndrome, insulin resistance, and systemic inflammation. In addition, the HDL₂-C/HDL₃-C ratio measured by vertical auto profile is significantly associated with the former factors even after comprehensive adjustment for HDL-C and other confounding variables.

Sex steroids mediate discrete effects on HDL cholesterol efflux capacity and particle concentration in healthy men

BACKGROUND

Exogenous testosterone decreases serum concentrations of high-density lipoprotein cholesterol (HDL-C) in men, but whether this alters cardiovascular risk is uncertain.

OBJECTIVE

To investigate the effects of testosterone and estradiol on HDL particle concentration (HDL-Pima) and metrics of HDL function.

METHODS

We enrolled 53 healthy men, 19 to 55 years of age, in a double-blinded, placebo-controlled, randomized trial. Subjects were rendered medically castrate using the GnRH receptor antagonist acyline and administered either (1) placebo gel, (2) low-dose transdermal testosterone gel (1.62%, 1.25 g), (3) full replacement dose testosterone gel (1.62%, 5 g) or (4) full replacement dose testosterone gel together with an aromatase inhibitor for 4 weeks. At baseline and end of treatment, serum HDL total macrophage and ABCA1-specific cholesterol efflux capacity (CEC), HDL-Pima and size, and HDL protein composition were determined.

RESULTS

Significant differences in serum HDL-C were observed with treatment across groups (P = .01 in overall repeated measures ANOVA), with increases in HDL-C seen after both complete and partial testosterone deprivation. Medical castration increased total HDL-Pima (median [interquartile range] 19.1 [1.8] nmol/L at baseline vs 21.3 [3.1] nmol/L at week 4, P = .006). However, corresponding changes in total macrophage CEC and ABCA1-specific CEC were not observed. Change in serum 17β-estradiol concentration correlated with change in total macrophage CEC (β = 0.33 per 10 pg/mL change in serum 17β-estradiol, P = .03).

CONCLUSIONS

Testosterone deprivation in healthy men leads to a dissociation between changes in serum HDL-C and HDL CEC. Changes in serum HDL-C specifically due to testosterone exposure may not reflect changes in HDL function.