Plasma proprotein convertase subtilisin kexin type 9 levels are related to markers of cholesterol synthesis in familial combined hyperlipidemia.

BACKGROUND AND AIMS: Two recent independent studies showed that patients with familial combined hyperlipidemia (FCHL) have elevated plasma levels of proprotein convertase subtilisin kexin type 9 (PCSK9) and markers of cholesterol synthesis. Both PCSK9 expression and cholesterol synthesis are downstream effects of hepatic activation of sterol regulatory element binding protein 2 (SREBP2). The present study was conducted to study the relationship between plasma PCSK9 and markers of cholesterol synthesis in FCHL. METHODS AND RESULTS: Markers of cholesterol synthesis (squalene, desmosterol, lathosterol), cholesterol absorption (campesterol, sitosterol, cholestanol) and PCSK9 were measured in plasma of FCHL patients (n = 103) and their normolipidemic relatives (NLR; n = 240). Plasma PCSK9, lathosterol and desmosterol levels were higher in FCHL patients than their NLR (p < 0.001, age and sex adjusted). Heritability calculations demonstrated that 35% of the variance in PCSK9 levels could be explained by additive genetic effects (p < 0.001). Significant age- and sex-adjusted correlations were observed for the relationship between PCSK9 and lathosterol, both unadjusted and adjusted for cholesterol, in the overall FCHL population (both p < 0.001). Multivariate regression analyses, with PCSK9 as the dependent variable, showed that the regression coefficient for FCHL status decreased by 25% (from 0.8 to 0.6) when lathosterol was included. Nevertheless, FCHL status remained an independent contributor to plasma PCSK9 (p < 0.001). CONCLUSIONS: The present study confirms the previously reported high and heritable PCSK9 levels in FCHL patients. Furthermore, we now show that high PCSK9 levels are, in part, explained by plasma lathosterol, suggesting that SREBP2 activation partly accounts for elevated PCSK9 levels in FCHL.

Differential effect of the rs4149056 variant in SLCO1B1 on myopathy associated with simvastatin and atorvastatin.

Statins reduce cardiovascular morbidity and mortality in appropriately selected patients. However, statin-associated myopathy is a significant risk associated with these agents. Recently, variation in the SLCO1B1 gene was reported to predict simvastatin-associated myopathy. The aim of this study was to replicate association of the rs4149056 variant in SLCO1B1 with severe statin-associated myopathy in a cohort of patients using a variety of statin medications and to investigate the association with specific statin types. We identified 25 cases of severe statin-associated myopathy and 84 controls matched for age, gender, statin type and dose. The rs4149056 variant in SLCO1B1 was not significantly associated with myopathy in this group as a whole. However, when subjects were stratified by statin type, the SLCO1B1 rs4149056 genotype was significantly associated with myopathy in patients who received simvastatin, but not in patients who received atorvastatin. Our findings provide further support for a role for SLCO1B1 genotype in simvastatin-associated myopathy, and suggest that this association may be stronger for simvastatin compared with atorvastatin.

Efficacy and safety of dalcetrapib in type 2 diabetes mellitus and/or metabolic syndrome patients, at high cardiovascular disease risk.

AIMS: Mixed dyslipidaemia, characterized by low levels of high-density lipoprotein cholesterol (HDL-C) and high levels of triglycerides, is common in patients with type 2 diabetes mellitus (T2DM) and/or metabolic syndrome. Dalcetrapib effectively increases HDL-C levels by modulating cholesteryl ester transfer protein (CETP) activity. The aim of this analysis was to investigate the lipid modifying efficacy and safety of dalcetrapib in patients with T2DM and/or metabolic syndrome. METHODS: Post hoc analysis of dalcetrapib therapy in five placebo-controlled, Phase II trials (4-48 weeks of duration) involving T2DM and/or metabolic syndrome, in dyslipidaemic patients with coronary heart disease (CHD) or CHD risk equivalent. RESULTS: Both in patients with and without T2DM and/or metabolic syndrome, dalcetrapib decreased CETP activity by 26-58% and increased HDL-C levels by 23-34%, depending on dose and duration of treatment. Dalcetrapib did not significantly affect low-density lipoprotein cholesterol (LDL-C) or apolipoprotein B levels. Treatment with dalcetrapib was generally well tolerated with a similar number of adverse events reported between patient groups and between those receiving dalcetrapib compared with placebo. CONCLUSIONS: Dalcetrapib similarly decreased CETP activity and increased HDL-C levels in patients with and without T2DM or metabolic syndrome; the ongoing Phase III dal-OUTCOMES study will help to determine if dalcetrapib's improvement in lipid levels also reduces cardiovascular morbidity and mortality.

Serum triglycerides and risk of cardiovascular disease.

Dyslipidemia, especially elevated serum levels of cholesterol, is causally related to cardiovascular disease. The specific role of triglycerides has long been controversial. In this article we discuss the role of serum triglycerides in relation to the risk of cardiovascular disease. First, the (patho)physiology of triglycerides is described, including the definition and a short summary of the primary and secondary causes of hypertriglyceridemia. Furthermore, we will give an overview of the published epidemiological studies concerning hypertriglyceridemia and cardiovascular disease to support the view that triglyceride-rich lipoproteins are an independently associated risk factor. Finally, treatment strategies and treatment targets are discussed. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.

Autoantibodies against oxidized low-density lipoprotein and lipid profile in patients with chronic periaortitis: case-control study.

Chronic periaortitis is thought to result from an autoallergic reaction to oxidized low-density lipoprotein (OxLDL). No data exist on lipid profile and atherosclerotic biomarkers. We investigated circulating levels of OxLDL and of anti-OxLDL (aOxLDL) antibodies in patients with chronic periaortitis using the cross-sectional case-control study on 20 patients with chronic periaortitis. Patients were compared to 20 age- and sex-matched controls. aOxLDL antibodies were measured by ELISA and expressed as mean optical density values at 450 nm from duplicate measurements (OD(450)). aOxLDL antibody titers (median [interquartile range]) did not differ significantly between patients and controls (aOxLDL-IgM: 0.70 [0.24-1.08] vs. 0.54 [0.25-0.73] OD(450); aOxLDL-IgG: 0.59 [0.38-0.75] vs. 0.41[0.33-0.63]OD(450)). Female patients had higher aOxLDL-IgM levels than male patients (1.02 [0.46-1.38] vs. 0.29 [0.22-0.84] OD(450); P = 0.05). aOxLDL-IgM titers were lower in patients with cardiovascular disease (CVD) than in patients without CVD (0.22 [0.16-0.37] vs. 0.92 [0.70-1.30] OD(450); P = 0.003) and correlated positively with HDL-cholesterol (r = 0.47, 95% CI 0.02-0.69; P = 0.03) and inversely with diastolic blood pressure (r = -0.46, 95% CI -0.75 to -0.01; P = 0.03) and OxLDL/apoB ratio (r = -0.41, 95% CI -0.73 to 0.04; P = 0.06). No differences or associations were found between aOxLDL-IgG titers and other variables between or within patients and/or controls. In patients OxLDL levels correlated with smoking pack-years (r = 0.58, 95% CI 0.17-0.81; P = 0.007). Data suggest a differing innate immune response to OxLDL in patients with chronic periaortitis compared to controls. Whether this response is causally related to chronic periaortitis development remains to be clarified.

Oxidized LDL enhances pro-inflammatory responses of alternatively activated M2 macrophages: a crucial role for Krüppel-like factor 2.

OBJECTIVE: Macrophages are key players in atherogenesis because of their properties to form foam cells that produce a large variety of pro-inflammatory mediators. We addressed the potency of phenotypic different macrophages to accumulate oxidized LDL. METHODS AND RESULTS: Surprisingly, anti-inflammatory M2 macrophages but not pro-inflammatory M1 macrophages rapidly accumulated oxidized LDL. Simultaneously, expression of Krüppel-like factor 2, a nuclear transcription factor known to suppress inflammation in endothelial cells and monocytes, decreased and the functional phenotype of M2 macrophages shifted towards a pro-inflammatory profile, characterized by higher production of IL-6, IL-8 and MCP-1 and lower expression of IL-10 upon stimulation with LPS. In contrast, Krüppel-like factor 2 expression and the phenotype of M1 macrophages remained largely unchanged upon oxidized LDL exposure. Downregulation of Krüppel-like factor 2 expression of M2 macrophages using siRNA technology led to a significant increase of LPS-induced MCP-1 secretion. CONCLUSIONS: We show that (1) anti-inflammatory M2 macrophages are more susceptible to foam cell formation than pro-inflammatory M1 macrophages, (2) exposure to oxidized LDL renders M2 macrophages pro-inflammatory, and (3) Krüppel-like factor 2 is involved in the enhanced secretion of MCP-1 by M2 macrophages loaded with oxidized LDL. The phenotype switch of M2 macrophages from an anti- to a pro-inflammatory profile may play an important role in pathogenesis of atherosclerosis, and could represent a novel therapeutic target.

Apolipoprotein B, non-HDL cholesterol and LDL cholesterol for identifying individuals at increased cardiovascular risk.

BACKGROUND: To compare apolipoprotein B (apoB), non-high-density lipoprotein-cholesterol (non-HDL-c) and low-density lipoprotein-cholesterol (LDL-c) for identifying individuals with a deteriorated cardiovascular (CV) risk profile, including a panel of subclinical atherosclerosis measurements and prevalent cardiovascular disease (CVD) in a Dutch population-based cohort. METHODS: Clinical and biochemical measurements and a panel of noninvasive parameters of subclinical atherosclerosis were determined in 1517 individuals, aged 50-70 years. RESULTS: Both men and women with increasing levels of apoB and non-HDL-c were more obese, had higher blood pressure and fasting glucose levels, and a more atherogenic lipid profile. Furthermore, compared to the reference group (composed of those with apoB, non-HDL-c and LDL-c levels in the bottom quartiles), participants with high apoB and high non-HDL-c levels had a lower ankle-brachial index at rest (-3.5% and -3.1%, respectively) and after exercise (-6.3% and -4.7%, respectively), a thicker near wall (+4.8% and +4.2%, respectively), far wall (both +6.2%), and mean intima-media thickness (+5.7% and +5.3%, respectively) and more plaques (+54.2% and +54.3%, respectively). In addition, they also showed increased stiffness parameters (e.g. pulse wave velocity both +3.6%). Less clear differences in CV risk profile and subclinical atherosclerosis parameters were observed when participants were stratified by LDL-c level. Furthermore, apoB but not LDL-c detected prevalent CVD, and non-HDL-c only detected prevalent CVD in men. The discriminatory power for prevalent CVD expressed as area under the receiver operating characteristic curve was 0.60 (P < 0.001) for apoB, 0.57 (P = 0.001) for non-HDL-c and 0.54 (P = 0.108) for LDL-c. CONCLUSION: Our data support the use of first apoB and secondly non-HDL-c above LDL-c for identifying individuals from the general population with a compromised CV phenotype.

Impact of waist circumference versus adiponectin level on subclinical atherosclerosis: a cross-sectional analysis in a sample from the general population.

OBJECTIVE: Waist circumference is a clinical marker of obesity and an established risk factor for cardiovascular (CV) disease. Adiponectin, an adipocyte-derived hormone and new biomarker of obesity, was recently proposed as the missing link between obesity and increased cardiovascular risk. We evaluated waist and adiponectin in a middle-aged population-based cohort to compare the impact of both obesity-markers on subclinical atherosclerosis, in relation to other CV risk factors. DESIGN, SETTING & SUBJECTS: Seven noninvasive measurements of atherosclerosis (NIMA), as surrogate markers of (subclinical) atherosclerosis, were determined in 1517 participants of the Nijmegen Biomedical Study, aged 50-70 years, who were drawn from the Dutch community. RESULTS: Both men and women with a high waist (M >104 cm; F >95 cm) showed increased pulse wave velocity (PWV) (M: +9.4%; F: +8.3%) and thicker intima-media thickness (IMT) (M: +7.3%; F: +4.3%) and women also showed increased plaque thickness (+16.6%). After adjustment for other CV risk factors both men and women showed increased IMT (M: +4.8%; F: +2.8%) and men also showed increased PWV (+9.6%). Both men and women with a low adiponectin level (M <2.2 mg L(-1); F <3.5 mg L(-1)) showed a decreased ankle-brachial index after exercise (M: -9.5%; F: -3.9%) and increased IMT (M: +3.7%; F: +3.6%) and women also showed increased PWV (+6.8%), but after adjustment for other CV risk factors low adiponectin level was no longer associated with deteriorated outcomes of NIMA. CONCLUSIONS: Waist circumference showed independent associations with noninvasive measurements of subclinical atherosclerosis, whereas the association of adiponectin level with subclinical atherosclerosis was not independent of other CV risk factors. Prospective studies are needed to elucidate, if the atherogenic effect of a low adiponectin level is mediated by other CV risk factors and not by low adiponectin level intrinsically.

Non-invasive measurements of atherosclerosis (NIMA): current evidence and future perspectives.

In clinical practice, cardiovascular (CV) risk stratification is based on the assessment of individual risk factors. Still many cardiovascular deaths occur in individuals who were not at high risk according to the current CV risk stratification models as the Systematic COronary Risk Evaluation chart (SCORE) and Framingham Risk Score. By measuring morphological and÷or functional abnormalities in the arterial wall directly, the impact of all CV risk factors together can be determined. In this review, the current status for the use of a panel of non-invasive measurements of atherosclerosis (NIMA) in CV risk prediction in clinical practice is discussed. Some of these NIMA showed predictive value for CV disease, such as intima-media thickness, pulse wave velocity, and ankle-brachial index, both in patients and in healthy and community-based populations. Recommendations have been made to include these NIMA in CV risk stratification in secondary prevention. However, the additional value of NIMA in CV risk stratification in primary prevention settings remains to be determined. Furthermore, the main determinants of NIMA are still unclear. Also the use of different combinations of NIMA should be evaluated, since different NIMA likely reflect different stages and aspects of the atherosclerotic process that leads to CV events. Future prospective studies should focus on repeated measures of NIMA to reveal the main determinants of the different NIMA and evaluate the predictive value of baseline versus repeated measurements.

Evaluation of cholesterol lowering treatment of patients with familial hypercholesterolemia: a large cross-sectional study in The Netherlands.

BACKGROUND: Heterozygous familial hypercholesterolemia (heFH) is a common autosomal dominant hereditary disorder caused by mutations in the LDL-receptor gene that lead to elevated plasma levels of low-density lipoprotein-cholesterol (LDL-c). Robust lowering of LDL-c levels is essential for risk reduction of premature cardiovascular diseases and early death. European and Dutch guidelines recommend to treat LDL-c to plasma levels <2.5mmol/l. In the present study we evaluated the treatment of heFH patients in The Netherlands. METHODS: A cross-sectional study was conducted in outpatient lipid clinics of three Academic Centers and two regional hospitals. Patient records of known heFH patients were retrieved and data were reviewed on the use of lipid-lowering medication, plasma lipids and lipoproteins, safety laboratory results and reasons for not achieving treatment goals. RESULTS: The data of 1249 patients with heFH were available. Nearly all patients (96%) were on statin treatment. The treatment goal for LDL-c <2.5mmol/l was achieved in 261 (21%) patients. Among those who did not reach LDL-c goals, 261 (27%) were on combination therapy of maximum statin dose and ezetimibe. Main reason (32%) why patients did not use maximum therapy despite an LDL-c >or=2.5mmol/l, was acceptance of a higher target LDL-c level by the treating physician. An alternative treatment goal of >50% LDL-c reduction, as recommended in the NICE guidelines, was achieved in 47% of patients with an LDL-c >or=2.5mmol/l and not using maximum therapy. CONCLUSION: Only a small proportion of patients with heFH reaches the LDL-c treatment target of <2.5mmol/l. These results emphasize the need for better monitoring, better utilization of available medication and for new treatment options in heFH to further decrease LDL-c levels.

Brachial artery diameter is related to cardiovascular risk factors and intima-media thickness.

BACKGROUND: Previous reports showed inconsistent results about the potential role of flow-mediated dilatation (FMD) in cardiovascular(CV) risk prediction. Few data are available about the role of nitroglycerin-mediated dilatation (NMD), but recently, brachial artery diameter(BAD) appeared to have predictive value in CV risk prediction.We determined the relation of FMD, BAD and NMD with known CV risk factors and intima-media thickness (IMT), a well-established surrogate marker of atherosclerosis, in a community-based population, the Nijmegen Biomedical Study (NBS). MATERIALS AND METHODS: FMD, BAD and NMD were measured in the brachial, and IMT in the common carotid artery ultrasononically in 337 participants, aged 50-70 years. Traditional clinical and biochemical parameters were determined. RESULTS: Both FMD and NMD were not correlated with most CV risk factors or prevalent CVD. However, both IMT and BAD did show significant correlations with CV risk factors. In accordance, both IMT and BAD were significantly correlated with prevalent CVD (r=0.62 and r=-0.37, respectively) . Furthermore, FMD was not correlated with IMT and did hardly (R2=1.1%) improve the prediction of IMT by CV risk factors in regression analysis. However, both BAD and NMD did correlate with IMT (r=-0.29 and r=0.25, respectively). CONCLUSION: In our study, FMD and NMD were not related to known CV risk factors and prevalent CVD, and FMD was not correlated with IMT, a surrogate marker of atherosclerosis. Most intriguingly, BAD was significantly correlated with some CV risk factors, prevalent CVD and IMT. So, BAD is a potential valuable tool in CV risk prediction in middle-aged low-risk populations, whereas FMD is not.

Anti-inflammatory therapy with tumour necrosis factor alpha inhibitors improves high-density lipoprotein cholesterol antioxidative capacity in rheumatoid arthritis patients.

OBJECTIVE: High-density lipoprotein (HDL) antiatherogenic functions seem to be diminished during inflammatory conditions such as rheumatoid arthritis (RA). The aim of this study was to investigate the effects of tumour necrosis factor (TNF) inhibition on the antioxidative capacity of HDL in RA. METHODS: Plasma lipids and paraoxonase (PON-1) activity were investigated in 45 RA patients, before and during 6 months of anti-TNF therapy. In addition, HDL was isolated and tested for its ability to inhibit copper-induced oxidation of low-density lipoprotein in vitro. RESULTS: Plasma HDL concentrations did not change considerably after 6 months of therapy. However, stable increases of PON-1 activities were observed throughout the same period (p<0.03). The increases were more obvious when related to HDL or apolipoprotein AI concentrations. HDL total antioxidative capacity significantly improved 6 months after the initiation of anti-TNF therapy (p = 0.015). The initial improvement of PON-1 activity paralleled a decrease in the inflammatory status, whereas specific TNF blockade was likely to be responsible for the long-term effects. CONCLUSIONS: Anti-TNF therapy with infliximab has beneficial effects on lipids through changes in HDL antioxidative capacity, which might be clinically relevant and contribute to the reported protective effect of anti-TNF on cardiovascular morbidity in RA. This emphasises the importance of HDL antiatherogenic capacity for cardiovascular risk in chronic inflammatory conditions.

Silent exonic mutations in the low-density lipoprotein receptor gene that cause familial hypercholesterolemia by affecting mRNA splicing.

In a large group of patients with the clinical phenotype of familial hypercholesterolemia, such as elevated low-density lipoprotein (LDL) cholesterol and premature atherosclerosis, but without functional mutations in the genes coding for the LDL receptor and apolipoprotein B, we examined the effect of 128 seemingly neutral exonic and intronic DNA variants, discovered by routine sequencing of these genes. Two variants, G186G and R385R, were found to be associated with altered splicing. The nucleotide change leading to G186G resulted in the generation of new 3'-splice donor site in exon 4 and R385R was associated with a new 5'-splice acceptor site in exon 9 of the LDL receptor gene. Splicing of these alternate splice sites leads to an in-frame 75-base pair deletion in a stable mRNA of exon 4 in case of G186G and R385R resulted in a 31-base pair frame-shift deletion in exon 9 and non-sense-mediated mRNA decay.

[No reason to start treatment with statins in patients with moderate to severe heart failure]. / Geen reden om te starten met statinen bij patiënten met matig tot ernstig hartfalen.

The 'Controlled rosuvastatin multinational trial in heart failure' (CORONA) recently reported that treatment with 10 mg of rosuvastatin per day has no significant effect on primary endpoints cardiovascular death, non-fatal myocardial infarction and non-fatal stroke in older patients with ischaemic systolic heart failure, despite a reduction in LDL-cholesterol of 45% to a level of 2.0 mmol/l. High sensitivity C-reactive protein was also reduced by 37%. The number of hospitalizations for cardiovascular disorders was significantly reduced. There were no more side effects in the rosuvastatin group than in the placebo group, even though the population consisted of elderly people with comorbidity and at risk for adverse drug interactions due to polypharmacy. There were no signs of any pleiotropic effects of statins in patients with heart failure. There seems to be no indication to start treatment with statins in patients with moderate to severe heart failure.

[Cardiovascular prevention in the over-80 age group is beneficial]. / Cardiovasculaire preventie bij 80-plussers is nuttig.

neHeart failure and stroke are the leading causes ofdisability and hospitalizations in the elderly. Treatment with statins and antihypertensives has been shown to reduce the risk of cardiovascular disease and stroke in trials including elderly persons. Preventive measures are therefore necessary to decrease and compress morbidity, improve quality of life and limit the costs of health care in the elderly. Therefore, old age is no reason in itself to withhold cardiovascular preventive treatment.

Cholesterol in end-stage renal disease: the good, the bad or the ugly?

The incidence of cardiovascular disease is markedly increased in patients with end-stage renal disease (ESRD). High serum cholesterol is widely recognised as a cardiovascular risk factor in the general population. However, in patients with ESRD high concentrations of cholesterol are associated with a better survival. This reverse epidemiology is, amongst others, caused by confounding due to malnutrition and chronic inflammation. In this population, treatment with statins to lower the serum cholesterol remains a matter of debate. In ESRD, LDL cholesterol is modified by increased oxidative stress. These altered LDL particles play a pivotal role in the development of atherosclerosis. Treatment with the antioxidant vitamin E has not equivocally been shown to be beneficial in this population. This review tries to put data from literature on dyslipidaemia and oxidative stress in ESRD in perspective.

Changing aspects of HFE-related hereditary haemochromatosis and endeavours to early diagnosis.

HFE-related hereditary haemochromatosis (HH) is an iron overload disease attributed to the highly prevalent homozygosity for the C282Y mutation in the HFE gene. The pathophysiology of this error in iron metabolism is not completely elucidated yet, although deficiency of the iron regulatory hormone hepcidin appears to play a role. Ways of diagnosing iron overload include measurement of the serum iron parameters, i.e. serum transferrin saturation and serum ferritin, by a liver biopsy or by calculating the amount of mobilisable body iron withdrawn by phlebotomies. Clinical signs attributed to HFE-related HH include liver failure, arthralgia, chronic fatigue, diabetes mellitus and congestive heart failure. organ failure can be prevented by phlebotomies starting before irreversible damage has occurred. Therefore, screening to facilitate early diagnosis is desirable in individuals at risk of developing HFE-related iron overload. over time it appeared that the clinical penetrance of the HFE mutations was much lower than had previously been thought. This changed the opinion about a suitable screening modality from case detection, via population screening, to family screening as the most appropriate method to prevent HFE-related disease. However, before the implementation of family screening it is vital to have thorough information on the relevance of the specific health problem involved, on the clinical penetrance of C282Y homozygosity and on the effectiveness of the screening approach.

Morbidity and mortality in first-degree relatives of C282Y homozygous probands with clinically detected haemochromatosis compared with the general population: the HEmochromatosis FAmily Study (HEFAS).

BACKGROUND: Family screening has been suggested as a sophisticated model for the early detection of HFE-related hereditary haemochromatosis (HH). However, until now, controlled studies on the morbidity and mortality in families with HH are lacking. METHODS: Data on iron parameters, morbidity and mortality were collected from 224 dutch C282Y-homozygous probands with clinically overt HH and 735 of their first-degree family members, all participating in the HEmochromatosis fAmily study (HEfAs). These data were compared with results obtained from an age- and gender-matched normal population. HEfAs and controls filled in similar questionnaires on demographics, lifestyle factors, health, morbidity and mortality. RESULTS: A significantly higher proportion of the HEfAs first-degree family members reported to be diagnosed with haemochromatosis-related diseases: 45.7 vs 19.4% of the matched normal population (McNemar p<0.001). Mortality among siblings, children and parents in the HEFAS population was similar to that in the relatives of matched control. CONCLUSION: In this study we show that, morbidity among first-degree family members of C282Y-homozygous probands previously diagnosed with clinically proven HH is higher than that in an age- and gender-matched normal population. Further studies are needed to definitely connect these increase morbidity figures to increase prevalenc of the C282Y mutated HFE-gene and elevated serum iron indices.