The maternal adaptation to pregnancy includes hyperlipidaemia, oxidative stress and chronic inflammation. In non-pregnant individuals, these processes are usually associated with poor vascular function. However, maternal vascular function is enhanced in pregnancy. It is not understood how this is achieved in the face of the adverse metabolic and inflammatory environment. Research into cardiovascular disease demonstrates that plasma HDL (high-density lipoprotein), by merit of its functionality rather than its plasma concentration, exerts protective effects on the vascular endothelium. HDL has vasodilatory, antioxidant, anti-thrombotic and anti-inflammatory effects, and can protect against endothelial cell damage. In pregnancy, the plasma HDL concentration starts to rise at 10 weeks of gestation, peaking at 20 weeks. The initial rise in plasma HDL occurs around the time of the establishment of the feto-placental circulation, a time when the trophoblast plugs in the maternal spiral arteries are released, generating oxidative stress. Thus there is the intriguing possibility that new HDL of improved function is synthesized around the time of the establishment of the feto-placental circulation. In obese pregnancy and, to a greater extent, in pre-eclampsia, plasma HDL levels are significantly decreased and maternal vascular function is reduced. Wire myography studies have shown an association between the plasma content of apolipoprotein AI, the major protein constituent of HDL, and blood vessel relaxation. These observations lead us to hypothesize that HDL concentration, and function, increases in pregnancy in order to protect the maternal vascular endothelium and that in pre-eclampsia this fails to occur.
Abstract High-density lipoprotein (HDL) is a circulating complex of lipids and proteins known primarily for its role in reverse cholesterol transport and consequent protection from atheroma. In spite of this, therapies aimed at increasing HDL concentration do not reduce the risk of cardiovascular disease (CVD), and as such focus has shifted towards other HDL functions protective of vascular health – including vasodilatory, anti-inflammatory, antioxidant and anti-thrombotic actions. It has been demonstrated that in disease states such as CVD and conditions of insulin resistance such as Type 2 diabetes mellitus (T2DM), HDL function is impaired owing to changes in the abundance and function of HDL-associated lipids and proteins, resulting in reduced vascular protection. However, the gold standard density ultracentrifugation technique used in the isolation of HDL also co-isolates extracellular vesicles (EVs). EVs are ubiquitous cell-derived particles with lipid bilayers that carry a number of lipids, proteins and DNA/RNA/miRNAs involved in cell-to-cell communication. EVs transfer their bioactive load through interaction with cell surface receptors, membrane fusion and endocytic pathways, and have been implicated in both cardiovascular and metabolic diseases – both as protective and pathogenic mediators. Given that studies using density ultracentrifugation to isolate HDL also co-isolate EVs, biological effects attributed to HDL may be confounded by EVs. We hypothesise that some of HDL’s vascular protective functions in cardiovascular and metabolic disease may be mediated by EVs. Elucidating the contribution of EVs to HDL functions will provide better understanding of vascular protection and function in conditions of insulin resistance and potentially provide novel therapeutic targets for such diseases.
Lipoprotein(a) is an independent risk factor for cardiovascular disease and recurrent ischemic stroke. Lipoprotein(a) levels are known to be associated with carotid artery stenosis, but the relation of lipoprotein(a) levels to carotid atherosclerotic plaque composition and morphology is less known. We hypothesize that higher lipoprotein(a) levels and lipoprotein(a)-related SNPs are associated with a more vulnerable carotid plaque and that this effect is sex-specific.In 182 patients of the Plaque At RISK study we determined lipoprotein(a) concentrations, apo(a) KIV-2 repeats and LPA SNPs. Imaging characteristics of carotid atherosclerosis were determined by MDCTA (n = 161) and/or MRI (n = 171). Regressions analyses were used to investigate sex-stratified associations between lipoprotein(a) levels, apo(a) KIV-2 repeats, and LPA SNPs and imaging characteristics.Lipoprotein(a) was associated with presence of lipid-rich necrotic core (LRNC) (aOR = 1.07, 95% CI: 1.00; 1.15), thin-or-ruptured fibrous cap (TRFC) (aOR = 1.07, 95% CI: 1.01; 1.14), and degree of stenosis (β = 0.44, 95% CI: 0.00; 0.88). In women, lipoprotein(a) was associated with presence of intraplaque hemorrhage (IPH) (aOR = 1.25, 95% CI: 1.06; 1.61). In men, lipoprotein(a) was associated with degree of stenosis (β = 0.58, 95% CI: 0.04; 1.12). Rs10455872 was significantly associated with increased calcification volume (β = 1.07, 95% CI: 0.25; 1.89) and absence of plaque ulceration (aOR = 0.25, 95% CI: 0.04; 0.93). T3888P was associated with absence of LRNC (aOR = 0.36, 95% CI: 0.16; 0.78) and smaller maximum vessel wall area (β = -10.24, 95%CI: -19.03; -1.44).In patients with symptomatic carotid artery stenosis, increased lipoprotein(a) levels were associated with degree of stenosis, and IPH, LRNC, and TRFC, known as vulnerable plaque characteristics, in the carotid artery. T3888P was associated with lower LRNC prevalence and smaller maximum vessel wall area. Further research in larger study populations is needed to confirm these results.
Abstract Background In pregnancy lipid levels increase with gestation resembling an atherogenic lipid profile. Currently it is unclear whether gestational lipid levels are associated with an adverse cardiovascular risk profile later in life. The aim of this study is to assess the association between gestational lipid levels and lipid levels and prevalence of the metabolic syndrome (MS) six years after pregnancy. Methods In plasma of 3510 women from the Generation R Study; a prospective population-based cohort, we measured lipid levels (total cholesterol, triglycerides and high-density lipoprotein cholesterol [HDL-c]), and low-density lipoprotein cholesterol (LDL-c), remnant cholesterol and non-HDL-c were calculated in early pregnancy (median 13.2 weeks, 90% range [10.5 to 17.1]) and six years after pregnancy (median 6.5 years, 90% range [6.2 to 7.8]). MS was assessed six years after pregnancy according to the NCEP/ATP3 criteria. We also examined the influence of pregnancy complications on these associations. Results Gestational lipid levels were positively associated with corresponding lipid levels six years after pregnancy, independent of pregnancy complications. Six years after pregnancy the prevalence of MS was 10.0%; the prevalence was higher for women with a previous placental syndrome (13.5%). Gestational triglycerides and remnant cholesterol in the highest quartile and HDL-c in the lowest quartile were associated with the highest risk for future MS, independent of smoking and body mass index. Conclusions Gestational lipid levels provide an insight in the future cardiovascular risk profile of women in later life. Monitoring and lifestyle intervention could be indicated in women with an unfavorable gestational lipid profile to optimize timely cardiovascular risk prevention.
Elevated levels of lipoprotein(a) [Lp(a)] are an independent risk factor for cardiovascular disease (CVD), particularly in individuals with type 2 diabetes. Although weight loss improves conventional risk factors for CVD in type 2 diabetes, the effects on Lp(a) are unknown and may influence the long-term outcome of CVD after diet-induced weight loss. The aim of this clinical study was to determine the effect of diet-induced weight loss on Lp(a) levels in obese individuals with type 2 diabetes. Plasma Lp(a) levels were determined by immunoturbidimetry in plasma obtained before and after 3–4 months of an energy-restricted diet in four independent study cohorts. The primary cohort consisted of 131 predominantly obese patients with type 2 diabetes (cohort 1), all participants of the Prevention Of Weight Regain in diabetes type 2 (POWER) trial. The secondary cohorts consisted of 30 obese patients with type 2 diabetes (cohort 2), 37 obese individuals without type 2 diabetes (cohort 3) and 26 obese individuals without type 2 diabetes who underwent bariatric surgery (cohort 4). In the primary cohort, the energy-restricted diet resulted in a weight loss of 9.9% (95% CI 8.9, 10.8) and improved conventional CVD risk factors such as LDL-cholesterol levels. Lp(a) levels increased by 14.8 nmol/l (95% CI 10.2, 20.6). In univariate analysis, the change in Lp(a) correlated with baseline Lp(a) levels (r = 0.38, p < 0.001) and change in LDL-cholesterol (r = 0.19, p = 0.033). In cohorts 2 and 3, the weight loss of 8.5% (95% CI 6.5, 10.6) and 6.5% (95% CI 5.7, 7.2) was accompanied by a median increase in Lp(a) of 13.5 nmol/l (95% CI 2.3, 30.0) and 11.9 nmol/l (95% CI 5.7, 19.0), respectively (all p < 0.05). When cohorts 1–3 were combined, the diet-induced increase in Lp(a) correlated with weight loss (r = 0.178, p = 0.012). In cohort 4, no significant change in Lp(a) was found (−7.0 nmol/l; 95% CI -18.8, 5.3) despite considerable weight loss (14.0%; 95% CI 12.2, 15.7). Diet-induced weight loss was accompanied by an increase in Lp(a) levels in obese individuals with and without type 2 diabetes while conventional CVD risk factors for CVD improved. This increase in Lp(a) levels may potentially antagonise the beneficial cardiometabolic effects of diet-induced weight reduction.
Abstract Aims/hypothesis Microvascular disease in type 2 diabetes is a significant cause of end-stage renal disease, blindness and peripheral neuropathy. The strict control of known risk factors, e.g. lifestyle, hyperglycaemia, hypertension and dyslipidaemia, reduces the incidence of microvascular complications, but a residual risk remains. Lipoprotein (a) [Lp(a)] is a strong risk factor for macrovascular disease in the general population. We hypothesised that plasma Lp(a) levels and the LPA gene SNPs rs10455872 and rs3798220 are associated with the incident development of microvascular complications in type 2 diabetes. Methods Analyses were performed of data from the DiaGene study, a prospective study for complications of type 2 diabetes, collected in the city of Eindhoven, the Netherlands ( n = 1886 individuals with type 2 diabetes, mean follow-up time = 6.97 years). To assess the relationship between plasma Lp(a) levels and the LPA SNPs with each newly developed microvascular complication (retinopathy n = 223, nephropathy n = 246, neuropathy n = 236), Cox proportional hazards models were applied and adjusted for risk factors for microvascular complications (age, sex, mean arterial pressure, non-HDL-cholesterol, HDL-cholesterol, BMI, duration of type 2 diabetes, HbA 1c and smoking). Results No significant associations of Lp(a) plasma levels and the LPA SNPs rs10455872 and rs3798220 with prevalent or incident microvascular complications in type 2 diabetes were found. In line with previous observations the LPA SNPs rs10455872 and rs3798220 did influence the plasma Lp(a) levels. Conclusions/interpretation Our data show no association between Lp(a) plasma levels and the LPA SNPs with known effect on Lp(a) plasma levels with the development of microvascular complications in type 2 diabetes. This indicates that Lp(a) does not play a major role in the development of microvascular complications. However, larger studies are needed to exclude minimal effects of Lp(a) on the development of microvascular complications.
Maternal lipid levels in early pregnancy are associated with maternal health and foetal growth. It is however unclear if maternal lipids in early pregnancy can be used to predict childhood lipid levels. The aim of this study is to assess the association between maternal and offspring childhood lipid levels, and to investigate the influence of maternal BMI and diet on these associations.This study included 2692 women participating in the Generation R study, an ongoing population-based prospective cohort study from early life onwards. Women with an expected delivery date between 2002 and 2006 living in Rotterdam, the Netherlands were included. Total cholesterol, triglycerides and high-density lipoprotein cholesterol (HDL-c) were measured in early pregnancy (median 13.2 weeks [90% range 10.6; 17.1]). Low-density lipoprotein cholesterol (LDL-c), remnant cholesterol and non-HDL-c were calculated. Corresponding lipid measurements were determined in 2692 children at the age of 6 (median 6.0 years [90% range 5.7; 7.5]) and 1673 children 10 years (median 9.7 years [90% range 9.5; 10.3]). Multivariate linear regression analysis was used to examine the association between maternal lipid levels in early pregnancy and the corresponding childhood lipid measurements at the ages of 6 and 10 years while adjusting for confounders.Maternal lipid levels in early pregnancy are positively associated with corresponding childhood lipid levels 6 and 10 years after pregnancy, independent of maternal body mass index and diet.Maternal lipid levels in early pregnancy may provide an insight to the lipid profile of children years later. Gestational lipid levels may therefore be used as an early predictor of children's long-term health. Monitoring of these gestational lipid levels may give a window-of-opportunity to start early interventions to decrease offspring's lipid levels and possibly diminish their cardiovascular risk later in life. Future studies are warranted to investigate the genetic contribution on maternal lipid levels in pregnancy and lipid levels of their offspring years later.