Lipoprotein(a) and Arterial Stiffness Parameters

Serum Lipoprotein(a) Levels as a Predictor of Aortic Stiffness in Patients on Long-Term Peritoneal Dialysis

BACKGROUND Lipoprotein (a) [Lp(a)] is associated with atherosclerosis and cardiovascular mortality in patients with kidney failure. Aortic stiffness (AS), measured primarily by carotid-femoral pulse wave velocity (cfPWV), reflects vascular aging and precedes end-organ failure. This study aimed to evaluate the association between serum Lp(a) levels and cfPWV in patients undergoing peritoneal dialysis (PD). MATERIAL AND METHODS In this cross-sectional study, which included 148 patients with long-term PD for end-stage kidney failure, cfPWV was measured using a cuff-based method. AS was defined as a cfPWV exceeding 10 m/s, and an enzyme-linked immunosorbent assay was used to determine serum Lp(a) levels. Univariate and multivariate regression analyses were performed to identify the clinical correlates of AS. RESULTS There were 32 (21.6%) patients diagnosed with AS. Based on the multivariate logistic regression analysis, the odds ratio for AS was 1.007 (95% confidence interval, 1.003-1.011; P=0.001) for every 1 mg/L increase in Lp(a) levels. Multivariate linear regression analysis showed that Lp(a) (P<0.001), age (P=0.003), waist circumference (P=0.008), systolic blood pressure (P=0.010), and diabetes mellitus (P<0.001) were positively associated with cfPWV. The area under the receiver operating characteristic curve for Lp(a) in differentiating AS from non-AS was 0.770 (95% confidence interval, 0.694-0.835; P<0.0001). CONCLUSIONS Serum Lp(a) level was independently associated with cfPWV and AS in patients with PD.

Association of Lipoprotein(a) with arterial stiffness: A Mendelian randomization study

BACKGROUND

In this study we used Mendelian randomization (MR) to investigate the potential causal association of lipoprotein (a) [Lp(a)] levels with pulse wave velocity (PWV).

METHODS

Genetic variants associated with Lp(a) were retrieved from the UK Biobank GWAS (N = 290,497). A non- overlapping GWAS based on a European cohort (N = 7,000) was used to obtain genetic associations with PWV (outcome) and utilized two different measures for the same trait, brachial-ankle (baPWV) and carotid-femoral (cfPWV) PWV. We applied a two-sample MR using the inverse variance weighting method (IVW) and a series of sensitivity analyses for 170 SNPs that were selected as instrumental variables (IVs).

RESULTS

Our analyses do not support a causal association between Lp(a) and PWV for neither measurement [βiwv(baPWV) = -.0005, p = .8 and βiwv(cfPWV) = -.006, p = .16]. The above findings were consistent across sensitivity analyses including weighted median, mode-based estimation, MR-Egger regression and MR-PRESSO.

CONCLUSION

We did not find evidence indicating that Lp(a) is causally associated with PWV, the gold standard marker of arterial stiffness.

Elevated Lipoprotein(a) Levels are Associated with Arterial Stiffness Measured by Cardio-Ankle Vascular Index in Patients Undergoing Peritoneal Dialysis

Background

Arterial stiffness (AS) can be used to predict future cardiovascular diseases. High lipoprotein(a) (Lp(a)) levels were independently correlated with cardiovascular (CV) morbidity and death in patients with chronic renal insufficiency. The cardio-ankle vascular index (CAVI) is a useful biomarker of arteriosclerotic disorders and has a close relationship with a variety of CV events. This study aimed to investigate the correlation between serum Lp(a) levels and AS in patients on peritoneal dialysis (PD) using the CAVI.

Methods

A total of 86 adult patients who were on regular PD for at least 3 months were recruited in this study. The CAVI values were determined using the waveform device (VaSera VS-1000). A CAVI value of ≥ 9.0 on either side was defined as high. Serum Lp(a) levels were measured by an enzyme-linked immunosorbent assay.

Results

Among these participants, 35 of 86 (40.7%) belonged to the high CAVI group. In contrast to those with a normal CAVI, PD recipients in the high CAVI group had higher serum levels of total cholesterol (p = 0.003), triglycerides (p = 0.044), C-reactive protein (p < 0.001), and Lp(a) (p < 0.001), whereas their albumin levels were significantly lower (p = 0.026). Based on multivariable logistic regression analysis, serum Lp(a) (odds ratio [OR] 1.025, 95% confidence interval [CI] 1.010-1.040, p = 0.001), total cholesterol (OR 1.042, 95% CI 1.005-1.081, p = 0.027), and C-reactive protein (each increase 0.1 mg/dL, OR 1.217, 95% CI 1.008-1.469, p = 0.041) levels were found as the parameters that could independently predict AS in patients on PD. Further, using Spearman's correlation analysis, both the left and right CAVIs revealed a significantly positive correlation with log-transformed Lp(a) levels (r = 0.588, p < 0.001; r = 0.639, p < 0.001, respectively).

Conclusions

Serum Lp(a) levels were postulated to participate in the pathogenic processes of AS in adult patients undergoing PD.

Lipoprotein(a) Serum Levels Predict Pulse Wave Velocity in Subjects in Primary Prevention for Cardiovascular Disease with Large Apo(a) Isoforms: Data from the Brisighella Heart Study

In the last decades, high serum levels of lipoprotein(a) (Lp(a)) have been associated with increased cardiovascular disease (CVD) risk, in particular among individuals with smaller apolipoprotein(a) (apo(a)) isoforms than those with larger sizes. The aim of our analysis was to evaluate whether Lp(a) levels could predict early vascular aging, and whether smaller apo(a) isoforms had a predictive value for vascular aging different than larger apo(a) isoforms in a cohort of subjects free from CVD. We considered the data of a subset of Brisighella Heart Study (BHS) participants free from CVD (462 men and 516 women) who were clinically evaluated during the 2012 BHS population survey. Predictors of arterial stiffness, measured as carotid-femoral pulse wave velocity (cfPWV) were estimated by the application of a step-wise linear regression model. In our cohort, there were 511 subjects with small apo(a) size and 467 subjects with large apo(a) isoforms. Subjects with larger apo(a) isoform sizes had significantly lower serum levels of Lp(a). In the BHS subpopulation sample, cfPWV was predicted by age, systolic blood pressure (SBP), serum levels of high-density lipoprotein cholesterol (HDL-C), triglycerides (TG) and sex, higher HDL-C serum levels and female sex associated with lower values of cfPWV. In subjects with smaller apo(a) isoform sizes, predictors of cfPWV were age, SBP, sex and serum levels of HDL-C, being higher HDL-C serum levels and female sex associated to lower values of cfPWV. In subjects with larger apo(a) isoform sizes, cfPWV was predicted by age, SBP, serum levels of Lp(a) and sex, with female sex associated with lower values of cfPWV. In our subpopulation sample, Lp(a) did not predict cfPWV. However, in subjects with large apo(a) isoform sizes, Lp(a) was a significant predictor of arterial stiffness.

Plasma Lipoprotein(a) Levels as Determinants of Arterial Stiffening in Hypertension

Previous studies have shown that plasma lipoprotein(a) (Lp(a)) plays an important role in the development of hypertensive organ damage. The aim of the present study was to investigate the relationship of Lp(a) with markers of arterial stiffening in hypertension. In 138 essential hypertensive patients free of diabetes, renal failure and cardiovascular complications, we measured plasma lipids and assessed vascular stiffness through the use of pulse wave analysis and calculation of the brachial augmentation index (AIx), and measured the pulse wave velocity (PWV). Plasma Lp(a) levels were significantly and directly related to both AIx (r = 0.490; p < 0.001) and PWV (r = 0.212; p = 0.013). Multiple regression analysis showed that AIx was independently correlated with age, C-reactive protein, and plasma Lp(a) (beta 0.326; p < 0.001), while PWV was independently and directly correlated with age, and inversely with HDL, but not with plasma Lp(a). Logistic regression indicated that plasma Lp(a) could predict an AIx value above the median for the distribution (p = 0.026). Thus, in a highly selective group of patients with hypertension, plasma Lp(a) levels were significantly and directly related to markers of vascular stiffening. Because of the relevance of vascular stiffening to cardiovascular risk, the reduction of Lp(a) levels might be beneficial for cardiovascular protection in patients with hypertension.

Gender-specific associations between apolipoprotein A1 and arterial stiffness in patients with nonalcoholic fatty liver disease

Background

Lipid metabolism factors may play an important role in the progression of nonalcoholic fatty liver disease (NAFLD) and its related cardiovascular dysfunctions. The study aims to assess whether Apolipoprotein A-1 (ApoA1) was associated with vascular stiffness in NAFLD patients.

Methods

From 2012 to 2013, we included 2,295 non-alcohol users with fatty liver disease (1,306 male patients) and completely excluded subjects who drank any alcohol ever to eliminate the effect of alcohol intake. The serum ApoA1 levels and the brachial-ankle pulse wave velocity (baPWV) were measured.

Results

The baPWV in men was much higher than in female patients (1,412.79 cm/s vs. 1,358.69 cm/s, P < 0.001). ApoA1 level was positively associated with baPWV odd ratio (OR), 4.18; 95% confidence interval (CI) [1.16-15.1], P < 0.05) in patients with AST/ALT < 1 and (OR, 4.70; 95% CI [1.36-16.23], P < 0.05) in patients with AST/ALT ≥ 1 respectively. Only arterial stiffness in men was associated with ApoA1 (OR, 3.96; 95% CI [1.29-12.30], P < 0.05) in logistics regression models adjusted for age, gender, body mass index, education attainment, physical activity, smoking, history of hypertension and high-density lipoprotein. The relationship between ApoA1 and baPWV in male NAFLD patients remained significant (confidence, 156.42; 95% CI [49.34-263.50], P < 0.05) in the fully adjusted linear regression model.

Conclusion

The serum ApoA1 was associated with arterial stiffness in male NAFLD patients. Increased ApoA1 level should be considered as an independent risk factor for arterial stiffness in male NAFLD patients, suggesting that NAFLD may alter arterial stiffness by "ApoA1-related" mechanism in men.

Lipoprotein(a) and inhibitors of proprotein convertase subtilisin/kexin type 9

Lipoprotein(a) [Lp(a)] has been identified as a risk factor for cardiovascular disease. Lp(a) levels are also high under certain clinical conditions, including familial hypercholesterolemia and high blood low-density lipoprotein (LDL) cholesterol levels. Few effective generic therapies for modulating Lp(a) have been developed. However, new therapies involving inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9) using monoclonal antibodies have markedly reduced the blood LDL levels-and the Lp(a) levels as well. Much attention has therefore been focused on this therapy and its utility. The mechanism by which PCSK9 inhibitors reduce the Lp(a) levels remains unclear. We here describe the effects of PCSK9 inhibitors on Lp(a) and discuss potential mechanisms and perspectives of this topic.