Plasma lipoprotein Lp(a), markers of haemostasis and inflammation, and risk and severity of coronary heart disease

Elevated plasma levels of lipoprotein(a) in psychiatric patients: a possible contribution to increased vascular risk

An increased incidence of adverse cardiovascular events has been reported in psychiatric patients, but the exact mechanisms underlying this association are still uncertain. Elevated plasma level of lipoprotein(a) [Lp(a)] is an independent risk factor for atherothrombotic disease in the general population. To study the implications of Lp(a) in psychiatric patients, we measured the plasma levels of Lp(a) in 74 patients with psychiatric disorders (39 schizophrenia, 10 major depression, 13 bipolar disorder and 12 personality disorder) and 74 healthy controls. The Lp(a) levels of the patient groups with schizophrenia, major depression and bipolar disorder were significantly higher than that of the control group. The median Lp(a) value of these diagnostic groups was comparable with those reported in patients with prior atherothrombotic events. On the other hand, no differences were found among personality disorder and controls. Our findings suggest that the elevation of plasma Lp(a) may contribute to increased cardiovascular risk in several patients with psychiatric disorders.

Impact of serum lipoprotein(a) on endothelium-dependent coronary vasomotor response assessed by intracoronary acetylcholine provocation

BACKGROUND

Lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerotic vascular disease. However, there are limited data regarding the impact of Lp(a) levels on the incidence and severity of endothelium-dependent coronary vasomotor response.

PATIENTS AND METHODS

A total of 2416 patients without significant coronary artery lesion (<50% stenosis) by coronary angiography and underwent acetylcholine (ACh) provocation test were enrolled and categorized according to their serum Lp(a) level into four quartile groups: less than 6.70, 6.70-13.30, 13.30-26.27, and more than 26.27 mg/dl. The aim of this study is to estimate the incidence and severity of endothelium-dependent positive ACh provocation test in each group; moreover, to access the incidence of major adverse cardiovascular events, the composite of total death, myocardial infarction, and de novo percutaneous coronary intervention were compared between the four groups up to 5 years.

RESULTS

The group with higher Lp(a) had a higher incidence of coronary heart disease, myocardial infarction, and peripheral arterial disease history. However, there was no difference among the four groups as regards the incidence of positive ACh provocation test, spasm severity, spasm extent, and location. However, at up to 5 years of clinical follow-up, the higher-Lp(a) group showed higher total death, de novo percutaneous coronary intervention, recurrent angina, and total major adverse cardiovascular events compared with the lower-Lp(a) groups.

CONCLUSION

In our study, there was no relationship between the elevated Lp(a) level and the vasospastic response to the intracoronary ACh provocation test; however, higher Lp(a) levels were associated with poor clinical outcomes up to 5 years.

Genetics of familial hypercholesterolemia: a tool for development of novel lipid lowering pharmaceuticals?

PURPOSE OF REVIEW

Familial hypercholesterolemia is characterized by high LDL cholesterol and an elevated risk to develop coronary heart disease. Mutations in LDL receptor-mediated cholesterol uptake are the main cause of familial hypercholesterolemia. However, multiple mutations in various other genes are also associated with high LDL cholesterol and even familial hypercholesterolemia. Thus, pharmaceuticals that target these genes and proteins might be attractive treatment options to reduce LDL cholesterol. This review provides an overview of the recent developments and clinical testing of such pharmaceuticals.

RECENT FINDINGS

About 80 genes are associated with hypercholesterolemia but only pharmaceuticals that inhibit cholesteryl ester transfer protein (CETP), angiopoietin-related protein 3 (ANGPTL3), and apolipoprotein C-III (apoC-III) have recently been tested in clinical trials. Inhibition of CETP and ANGPTL3 lowered LDL cholesterol. ANGPTL3 inhibition had the largest effect and was even effective in familial hypercholesterolemia patients. The effect of apoC-III inhibition on LDL cholesterol is not conclusive.

SUMMARY

Of the many potential pharmaceutical targets involved in LDL cholesterol, only a few have been studied so far. Of these, pharmaceuticals that inhibit CETP or ANGPTL3 are promising novel treatment options to reduce LDL cholesterol but the effect of apoC-III inhibition requires more research.

Lipoprotein(a) level associates with coronary artery disease rather than carotid lesions in patients with familial hypercholesterolemia

BACKGROUND

Lipoprotein(a) [Lp(a)] level is a novel risk factor for atherosclerotic cardiovascular disease in patients with familial hypercholesterolemia (FH), while its impact on the different sites of arteries remains undetermined. We aim to examine the associations of Lp(a) levels with coronary and carotid atherosclerosis in patients with heterozygous FH (HeFH).

METHODS

A total of 148 patients with HeFH who have received carotid ultrasonography and coronary angiography due to chest pain were enrolled. Plasma Lp(a) was measured using immunoturbidimetric method. Finally, the associations between Lp(a) and coronary as well as carotid lesions were evaluated.

RESULTS

Patients with Lp(a) ≥ 300 mg/L had similar carotid intima-media thickness (IMT, 0.782 ± 0.16 mm vs 0.798 ± 0.18 mm, P = .579) and plaque prevalence (66.7% vs 65%, P = .833) compared to those with Lp(a) < 300 mg/L, but had a higher prevalence of coronary artery disease (CAD, 69.7% vs 50.0%, P = .016) and higher Gensini score (GS, median 27 vs 3, P = .006). Moreover, no correlations were found between carotid mean IMT with either Lp(a) level or Lp(a) year score, while positive relation of Lp(a) with GS did. Multivariate regression analysis revealed that Lp(a), Lp(a) year score, and Lp(a) ≥ 300 g/L were all independent predictors for the presence of CAD (OR = 4.99, P = .007; OR = 4.73, P = .009; OR = 4.46, P = .006, respectively) but not for carotid plaques.

CONCLUSIONS

This study suggested that Lp(a) level was associated with the presence and severity of CAD but not with carotid atherosclerosis in patients with HeFH.

Incidence of elevated lipoprotein (a) levels in a large cohort of patients with cardiovascular disease

Background

Recently it has been demonstrated that elevated lipoprotein (a) (LPA) levels are associated with an increased risk of cardiovascular disease across multiple ethnic groups. However, there is only scanty data about the incidence of elevated LPA levels in different patient cohorts. As a consequence, we aimed to examine whether patients with elevated LPA levels might be seen more often in a cardiovascular center in comparison to the general population.

Methods

We reviewed LPA concentrations of 52,898 consecutive patients who were admitted to our hospital between January 2004 and December 2014. We subdivided them into different groups according to their LPA levels. Data was compared to available information in medical literature.

Results

26.4% of the patients had LPA levels >30 mg/dl which is in line with the data from literature. Mean level of LPA concentration in our study was twice as high in comparison to the general population (25.8% vs. 13.3%). 4.6% had LPA levels >98 mg/dl (general population <0.3%).

Conclusion

In patients admitted to a cardiovascular center the proportion of LPA >30 mg/dl is comparable to the general population but mean levels over all are twice as high and the proportion of patients with LPA levels of >98 mg/dl is extremely higher.

Lipoprotein (a) is related to coronary atherosclerotic burden and a vulnerable plaque phenotype in angiographically obstructive coronary artery disease

BACKGROUND

Lipoprotein Lp(a) has been shown to be an independent risk factor for coronary artery disease (CAD). However, its association with CAD burden in patients with ACS is largely unknown, as well as the association of Lp(a) with lipid rich plaques prone to rupture.

AIM

We aim at assessing CAD burden by coronary angiography and plaque features including thin cap fibroatheroma (TCFA) by optical coherence tomography (OCT) in consecutive patients presenting with acute coronary syndrome (ACS) and obstructive CAD along with serum Lp(a) levels.

METHODS

This study comprises an angiographic and an OCT cohort. A total of 500 ACS patients (370 men, average age 66 ± 11) were enrolled for the angiographic cohort and 51 ACS patients (29 males, average age 65 ± 11) were enrolled for the OCT cohort. Angiographic CAD severity was assessed by Sullivan score and by Bogaty score including stenosis score and extent index. OCT plaque features were evaluated at the site of the minimal lumen area and along the culprit segment.

RESULTS

In the angiographic cohort, at multivariate analysis, Lp(a) was a weak independent predictor of Sullivan score (p < 0.0001), stenosis score (p < 0.0001) and extent index (p < 0.0001). In the OCT cohort, patients with higher Lp(a) levels (≥ 30 md/dl) compared to patients with lower Lp(a) levels (<30 md/dl) exhibited a higher prevalence of lipidic plaque at the site of the culprit stenosis (67% vs. 27%; P = 0.02), a wider lipid arc (135 ± 114 vs 59 ± 111; P = 0.03) and a higher prevalence of TCFA (38% vs. 10%; P = 0.04).

CONCLUSIONS

Among patients with ACS, raised Lp(a) levels are associated with an increased atherosclerotic burden and it identifies a subset of patients with features of high risk coronary atherosclerosis.

[Lipoprotein(a): influence on cardiovascular manifestation]

The clinical relevance of lipoprotein(a) (Lp(a)) as a cardiovascular risk factor is currently underestimated. The aim of our study was to assess the influence of increased Lp(a) values on the development and severity of coronary artery disease (CAD).In our retrospective analysis of 31,274 patients, who were hospitalized for the first time, we compared patients with isolated increased Lp(a) (> 110 mg/dl) and normal Lp(a) (< 30 mg/dl), with increased Lp(a) concentrations (30-60 mg/dl, 61-90 mg/dl, 91-110 mg/dl), and in a third analysis with additionally increased LDL cholesterol and HbA1c values.Patients with high Lp(a) levels showed a significantly higher incidence of advanced CAD with a three-vessel disease being present in 50.2 vs. 25.1 %. Patients with high Lp(a) levels had a significantly more frequent history of myocardial infarction (34.6 vs. 16.6 %, p < 0.001), surgical myocardial revascularization (40.8 vs. 20.8 %, p < 0.001) and percutaneous coronary intervention (55.3 vs. 33.6 %, p < 0.001). In addition, there was a marked difference in gender to the disadvantage of male patients regarding development and severity of CAD. CAD risk (Odds ratio) was increased 5.5-fold in patients with Lp(a) ≥ 110 mg/dl. Additionally elevated LDL and HbA1c levels were not associated with increased manifestation and severity of CAD.High Lp(a) concentration leads to an increased manifestation and severity of coronary artery disease. Additional risk factors do not aggravate manifestation of CAD.

Lipoprotein(a) in cardiovascular diseases

Lipoprotein(a) (Lp(a)) is an LDL-like molecule consisting of an apolipoprotein B-100 (apo(B-100)) particle attached by a disulphide bridge to apo(a). Many observations have pointed out that Lp(a) levels may be a risk factor for cardiovascular diseases. Lp(a) inhibits the activation of transforming growth factor (TGF) and contributes to the growth of arterial atherosclerotic lesions by promoting the proliferation of vascular smooth muscle cells and the migration of smooth muscle cells to endothelial cells. Moreover Lp(a) inhibits plasminogen binding to the surfaces of endothelial cells and decreases the activity of fibrin-dependent tissue-type plasminogen activator. Lp(a) may act as a proinflammatory mediator that augments the lesion formation in atherosclerotic plaques. Elevated serum Lp(a) is an independent predictor of coronary artery disease and myocardial infarction. Furthermore, Lp(a) levels should be a marker of restenosis after percutaneous transluminal coronary angioplasty, saphenous vein bypass graft atherosclerosis, and accelerated coronary atherosclerosis of cardiac transplantation. Finally, the possibility that Lp(a) may be a risk factor for ischemic stroke has been assessed in several studies. Recent findings suggest that Lp(a)-lowering therapy might be beneficial in patients with high Lp(a) levels. A future therapeutic approach could include apheresis in high-risk patients in order to reduce major coronary events.

Plasma levels of lipoprotein (a) in patients with major depressive disorders

Depression and cardiovascular disease are among the most prevalent health problems. The evidence that depression is a risk factor for the development and progression of coronary heart disease has strengthened over the past several years, but the exact reasons are not yet clear. Elevated lipoprotein (a) (Lp(a)) concentrations seem to be the major factor for the progression of the atherosclerosis and coronary heart disease. In this study, we measured the plasma levels of Lp(a) in 35 patients with major depressive disorder and 35 healthy controls. The two groups were matched by age and gender. Lp(a) measurement was performed using an immunoturbidimetric method. Total cholesterol was significantly lower in the patient group (mean +/-SD: 144.65+/-22.13 vs. 186.14+/-34.48 mg/dl. The Lp(a) levels of the patient group differed significantly from control values. Patients with major depressive disorder had higher plasma levels of Lp(a) than healthy controls (34.94+/-18.01 vs. 20.08+/-11.27 mg/dl). The results of the present study suggest that the increase of Lp(a) may contribute to higher cardiovascular risk in patients with major depressive disorder.

Long term effects on human plasma lipoproteins of a formulation enriched in butter milk polar lipid

Background

Sphingolipids (SL), in particular sphingomyelin (SM) are important components of milk fat polar lipids. Dietary SM inhibits cholesterol absorption in rats (Nyberg et al. J Nutr Biochem. 2000) and SLs decrease both cholesterol and TG concentrations in lipid- and cholesterol fed APOE*3Leiden mice (Duivenvoorden et al. Am J Clin Nutr. 2006). This human study examines effects of a butter milk formulation enriched in milk fat globule membrane material, and thereby in SLs, on blood lipids in healthy volunteers. In a four week parallel group study with 33 men and 15 women we examined the effects of an SL-enriched butter milk formulation (A) and an equivalent control formulation (B) on plasma lipid levels. Plasma concentrations of HDL and LDL cholesterol, triacylglycerols (TG), apolipoproteins AI and B, and lipoprotein (a) were measured. The daily dose of SL in A was 975 mg of which 700 mg was SM. The participants registered food and drink intake four days before introducing the test formula and the last four days of the test period.

Results

A daily increase of SL intake did not significantly influence fasting plasma lipids or lipoproteins. In group B TG, cholesterol, LDL, HDL and apolipoprotein B concentrations increased, however, but not in group A after four weeks. The difference in LDL cholesterol was seen primarily in women and difference in TG primarily in men. No significant side effects were observed.

Conclusion

The study did not show any significant decrease on plasma lipids or lipoprotein levels of an SL-enriched formulation containing 2-3 times more SL than the normal dietary intake on cholesterol, other plasma lipids or on energy intake. The formulation A may, however, have counteracted the trend towards increased blood lipid concentrations caused by increased energy intake that was seen with the B formulation.

Interactions of lipoprotein(a) with diabetes mellitus, apolipoprotein B and cholesterol enhance the prognostic values for coronary artery disease

BACKGROUND

Synergistic interactions between elevated serum lipoprotein(a) [Lp(a)] and other unfavorable risk factors have been proposed to cause very high risk for coronary artery disease (CAD). The aim of this study was to examine the potential interactions between Lp(a) and other risk factors.

METHODS

The profiles of serum (apo)(lipo)proteins, markers of inflammation, indicators of hemoconcentration as well as classical risk factors were determined in 264 clinically stable angiographically documented subjects. Correlation, linear and logistic regression and stratification analyses were performed.

RESULTS

The frequency and severity of CAD and the prevalence of diabetes mellitus were significantly higher in the 3rd relative to 1st tertile of Lp(a). Subjects with Lp(a) levels in the upper tertile had significantly higher levels of serum glucose, total cholesterol and low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (apoB), calcium, phosphate and their ion product. Bivariate correlation analysis indicated that serum Lp(a) was associated positively with the occurrence and severity of CAD, diabetes mellitus and the levels of serum glucose, cholesterol, LDL-C, apoB, calcium, phosphate and inversely to physical inactivity. In linear regression analysis, LDL-C (or apoB), diabetes, physical inactivity and phosphate were the major independent determinants of Lp(a) values. In multiple logistic regression analysis, after adjusting for major risk factors, Lp(a) showed a significant and independent association with the prevalence of CAD. By constructing dummy combined variables, elevated Lp(a) accompanied with diabetes or high levels of serum glucose, apoB and cholesterol exhibited an amplified high risk for CAD.

CONCLUSIONS

The results indicate that serum Lp(a) does interact multiplicatively with diabetes, apoB and cholesterol. The simultaneous assessment of Lp(a) and interactive risk factors enhances the discriminating value for CAD.