Effect of antiretroviral therapy on allele-associated Lp(a) level in women with HIV in the Women's Interagency HIV Study

Lipoprotein(a) - From Biomarker to Therapy: A Review for the Clinician

Cardiovascular disease (CVD) remains the predominant cause of morbidity and mortality globally. Amid rising CVD rates, Lipoprotein(a) [Lp(a)] has been recognized as a critical biomarker identifying individuals at an increased risk of atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valve stenosis (AS), independent of traditional risk factors. Lp(a) is a lipoprotein variant similar to LDL but includes apolipoprotein(a), which influences its pathogenic potential. Elevated Lp(a) levels are genetically determined and have been implicated in promoting vascular inflammation, atherogenesis, enhanced calcification, and thrombosis. Emerging antisense oligonucleotide (ASO)- and small interfering ribonucleic acids (siRNAs)- based therapies have been shown to lower Lp(a) concentrations, with ongoing trials underway to determine whether they reduce the risk of CVD. While guidelines on screening and management continue to evolve, the advent of specific Lp(a)-lowering therapies may transform CVD prevention and treatment. This review aims to consolidate the current knowledge on Lp(a) from its biological functions to its implications for clinical practice, focusing on its role as a biomarker and potential therapeutic target.

Lipoprotein(a) Is Elevated and Inversely Related to Coronary Endothelial Function in People With HIV

BACKGROUND

HIV-associated cardiovascular disease (CVD) is increasing in prevalence. The mechanisms underlying the heightened cardiovascular risk faced by people with HIV (PWH), however, remain poorly defined. Recent studies indicate an important role of lipoprotein(a) (Lp[a]) in predicting CVD risk in the general population, but little is known regarding its role in HIV-associated CVD. Thus, we sought to evaluate whether Lp(a) is elevated in PWH and if it is associated with impaired coronary endothelial function (CEF), a known mediator of CVD in PWH.

METHODS AND RESULTS

In this cross-sectional study, cardiac magnetic resonance imaging with isometric handgrip exercise, an endothelial dependent stressor, was performed to assess CEF in 65 PWH and 52 controls without HIV. Percent changes in coronary cross-sectional area and coronary blood flow from rest to stress were used to quantify CEF. Lp(a) levels were assessed by immunoturbidimetric assay at the time of magnetic resonance imaging. Lp(a) levels were higher in PWH compared with controls (78 nmol/L [39-137 nmol/L] versus 45.5 nmol/L [18-102.5 nmol/L], P<0.01). Both percent change in coronary cross-sectional area (0.38% [-6.1% to 5.4%] versus 7.43% [2.4%-11.2%], P<0.0005) and coronary blood flow (9.1% [-1.3% to 23.1%] versus 24.1% [3.3%-39.8%], P<0.05) were lower in PWH compared with controls. In PWH, Lp(a) was inversely associated with percent change in coronary cross-sectional area (β=-6.18±1.01%/nmol/L, P<0.001) but not with percent change in coronary blood flow even after adjustment for confounding risk factors. No association between Lp(a) and measures of CEF was observed in individuals without HIV.

CONCLUSIONS

Lp(a) concentrations are elevated in PWH and inversely related to CEF in PWH.

Elevated lipoprotein(a) levels: A crucial determinant of cardiovascular disease risk and target for emerging therapies

Cardiovascular disease (CVD) remains a significant global health challenge despite advancements in prevention and treatment. Elevated Lipoprotein(a) [Lp(a)] levels have emerged as a crucial risk factor for CVD and aortic stenosis, affecting approximately 20 of the global population. Research over the last decade has established Lp(a) as an independent genetic contributor to CVD and aortic stenosis, beginning with Kare Berg's discovery in 1963. This has led to extensive exploration of its molecular structure and pathogenic roles. Despite the unknown physiological function of Lp(a), studies have shed light on its metabolism, genetics, and involvement in atherosclerosis, inflammation, and thrombosis. Epidemiological evidence highlights the link between high Lp(a) levels and increased cardiovascular morbidity and mortality. Newly emerging therapies, including pelacarsen, zerlasiran, olpasiran, muvalaplin, and lepodisiran, show promise in significantly lowering Lp(a) levels, potentially transforming the management of cardiovascular disease. However, further research is essential to assess these novel therapies' long-term efficacy and safety, heralding a new era in cardiovascular disease prevention and treatment and providing hope for at-risk patients.

Association of Lipoprotein(a) with peri-coronary inflammation in persons with and without HIV infection

BACKGROUND

Persons with human immunodeficiency virus (HIV) (PWH) have an increased risk of developing cardiovascular disease (CVD) compared to persons without HIV (PWoH). Lipoprotein(a) [Lp(a)] is a known atherosclerotic risk factor in PWoH, but there are no studies investigating Lp(a) and peri-coronary inflammation.

OBJECTIVE

To investigate whether Lp(a) is associated with peri-coronary inflammation as assessed by the fat attenuation index (FAI) and activated monocytes and T lymphocytes in PWH and PWoH.

METHODS

We measured plasma levels of Lp(a) at study entry in 58 PWH and 21 PWoH without CVD and who had FAI measurements. Associations of Lp(a) with FAI values of the right coronary artery (RCA) and left anterior descending artery were evaluated using multivariable regression models adjusted for potential confounders. Correlations between Lp(a) levels and systemic inflammatory markers and immune cell subsets were examined.

RESULTS

Lp(a) was associated with greater peri-coronary inflammation among PWH compared to PWoH (β=1.73, P=0.019) in the RCA, in adjusted models. Significant correlations were observed with certain inflammatory markers (tumor necrosis factor receptor [TNFR]-I, b=0.295, P<0.001; TNFR-II, b=0.270, P=0.002; high-sensitivity C-reactive protein, b=0.195, P=0.028). Significant correlations were found between Lp(a) levels and several markers of monocyte activation: CD16 -CD163+ (b= -0.199, P=0.024), and CD16 -DR+ MFI (b= -0.179, P=0.042) and T cell subset CD38+CD4+ TEMRA (b= 0.177, P= 0.044).

CONCLUSIONS

Lp(a) was associated with greater peri-coronary inflammation in the RCA in PWH compared to PWoH, as well as with select systemic inflammatory markers and specific subsets of immune cells in peripheral circulation.

Effects of Lipid-Modifying and Other Drugs on Lipoprotein(a) Levels-Potent Clinical Implications

The past few years have shown an ongoing interest in lipoprotein(a) (Lp(a)), a lipid molecule that has been proven to have atherogenic, thrombogenic, and inflammatory properties. Several lines of evidence, indeed, have demonstrated an increased risk of cardiovascular disease as well as calcific aortic valve stenosis in patients with elevated Lp(a) levels. Statins, the mainstay of lipid-lowering therapy, slightly increase Lp(a) levels, while most other lipid-modifying agents do not significantly alter Lp(a) concentrations, except for proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors. The latter have been shown to reduce Lp(a) levels; however, the clinical significance of this effect has not been clearly elucidated. Of note, the pharmaceutical lowering of Lp(a) may be achieved with novel treatments specifically designed for this purpose (i.e., antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs)). Large clinical trials with cardiovascular outcomes with these agents are ongoing, and their results are eagerly awaited. Furthermore, several non-lipid-modifying drugs of various classes may influence Lp(a) concentrations. We have searched MEDLINE, EMBASE, and CENTRAL databases up to 28 January 2023 and summarized the effects of established and emerging lipid-modifying drugs and other medications on Lp(a) levels. We also discuss the potent clinical implications of these alterations.

Are we seeing the light at the end of the tunnel for high lipoprotein(a)? Lipoprotein(a)

Lipoprotein (a) (Lp(a)) attests to be of interest as a new lipoprotein target. However, Lp(a) was discovered in 1963 and since then was recognized as a low-density lipoprotein (LDL)-like lipoprotein with a structurally similar domain to plasminogen. We are increasingly recognizing the importance of Lp(a) and cardiovascular pathologies including atherosclerotic cardiovascular disease, aortic valve stenosis, heart failure, and atrial fibrillation. However, we neither have a standardized measurement method nor an appropriate agent to intervene with this old threat that we have recognized for more than 50 years. Herein, we present an up-to-date review of our knowledge about Lp(a) covering measurement methods, its associates, and summary of the currently available therapies and emerging therapeutic agents for the management of high Lp(a) in the light of recent evidence and guideline recommendations

Lipoprotein(a) in atherosclerotic cardiovascular disease and aortic stenosis: a European Atherosclerosis Society consensus statement

This 2022 European Atherosclerosis Society lipoprotein(a) [Lp(a)] consensus statement updates evidence for the role of Lp(a) in atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis, provides clinical guidance for testing and treating elevated Lp(a) levels, and considers its inclusion in global risk estimation. Epidemiologic and genetic studies involving hundreds of thousands of individuals strongly support a causal and continuous association between Lp(a) concentration and cardiovascular outcomes in different ethnicities; elevated Lp(a) is a risk factor even at very low levels of low-density lipoprotein cholesterol. High Lp(a) is associated with both microcalcification and macrocalcification of the aortic valve. Current findings do not support Lp(a) as a risk factor for venous thrombotic events and impaired fibrinolysis. Very low Lp(a) levels may associate with increased risk of diabetes mellitus meriting further study. Lp(a) has pro-inflammatory and pro-atherosclerotic properties, which may partly relate to the oxidized phospholipids carried by Lp(a). This panel recommends testing Lp(a) concentration at least once in adults; cascade testing has potential value in familial hypercholesterolaemia, or with family or personal history of (very) high Lp(a) or premature ASCVD. Without specific Lp(a)-lowering therapies, early intensive risk factor management is recommended, targeted according to global cardiovascular risk and Lp(a) level. Lipoprotein apheresis is an option for very high Lp(a) with progressive cardiovascular disease despite optimal management of risk factors. In conclusion, this statement reinforces evidence for Lp(a) as a causal risk factor for cardiovascular outcomes. Trials of specific Lp(a)-lowering treatments are critical to confirm clinical benefit for cardiovascular disease and aortic valve stenosis.

Evolocumab treatment in patients with HIV and hypercholesterolemia/mixed dyslipidemia: BEIJERINCK study design and baseline characteristics

BACKGROUND

People living with human immunodeficiency virus (PLHIV) are at higher risk of atherosclerotic cardiovascular disease (ASCVD) due to traditional and HIV- or antiretroviral treatment (ART)-related risk factors. The use of high-intensity statin therapy is often limited by comorbidities and drug-drug interactions with ART. Herein, we present the design and baseline characteristics of the BEIJERINCK study, which will assess the safety and efficacy of evolocumab in PLHIV and hypercholesterolemia/mixed dyslipidemia.

METHODS

Randomized, double-blind, placebo-controlled, multinational trial that investigates monthly subcutaneous evolocumab 420 mg versus placebo in PLHIV with hypercholesterolemia/mixed dyslipidemia who are treated with maximally-tolerated statin therapy. The primary outcome is the baseline to week 24 percent change in low density lipoprotein cholesterol (LDL-C). Secondary outcomes include achievement of LDL-C < 70 mg/dL and percent change in other plasma lipid and lipoprotein levels. Safety will also be examined.

RESULTS

This study enrolled and dosed 464 patients who had a mean age of 56.4 years and were mostly male (82.5%). Mean duration with HIV was 17.4 years, and, by design, HIV viral load at screening was ≤50 copies/mL. ASCVD was documented in 35.6% of patients. Mean LDL-C of enrolled patients at baseline was 133.3 mg/dL. Statin use was prevalent (79.3% overall) with 74.6% receiving moderate or high-intensity statins. In total, 20.7% of patients did not receive statins due to intolerance/contraindications.

CONCLUSIONS

The BEIJERINCK study is the first clinical trial to examine the lipid-lowering efficacy and safety of a fully human PCSK9 monoclonal antibody inhibitor in a moderate/high cardiovascular risk population of PLHIV.

Elevated Lipoprotein(a) in Perinatally HIV-Infected Children Compared With Healthy Ethnicity-Matched Controls

Background

HIV-associated cardiovascular disease (CVD) risk in combination antiretroviral therapy (cART)-treated perinatally HIV-infected patients (PHIV+) remains unknown due to the young age of this population. Lipoprotein(a) (Lp(a)) has been established as an independent causal risk factor for CVD in the general population but has not been well established in the population of PHIV+.

Methods

We cross-sectionally compared lipid profiles, including nonfasting Lp(a), together with total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides between 35 cART-treated PHIV+ children aged 8-18 years and 37 controls who were matched for age, sex, ethnicity, and socioeconomic status. We explored associations between Lp(a) and disease- and treatment-related factors (inflammation, monocyte activation, and vascular), biomarkers, and neuroimaging outcomes using linear regression models.

Results

PHIV+ children had significantly higher levels of Lp(a) compared with controls (median, 43.6 [21.6-82.4] vs 21.8 [16.8-46.6] mg/dL; P = .033). Other lipid levels were comparable between groups. Additional assessment of apolipoprotein B, apolipoprotein CIII, apolipoprotein E, and APOE genotype revealed no significant differences. Higher Lp(a) levels were associated with higher plasma apoB levels and with lower monocyte chemoattractant protein-1 and TG levels in PHIV+ children. Lp(a) was not associated with HIV- or cART-related variables or with neuroimaging outcomes.

Conclusions

cART-treated PHIV+ children appear to have higher levels of Lp(a) compared with ethnicity-matched controls, which may implicate higher CVD risk in this population. Future research should focus on the association between Lp(a) and (sub)clinical CVD measurements in cART-treated PHIV+ patients.

Dutch Trial Register number

NRT4074.

Heritability of apolipoprotein (a) traits in two-generational African-American and Caucasian families

Heritability of LPA allele, apo(a) isoform sizes, and isoform-associated lipoprotein(a) [Lp(a)] levels was studied in 82 Caucasian and African-American families with two parents and two children (age: 6-74 years). We determined: 1) Lp(a) levels; 2) LPA allele sizes; 3) apo(a) isoform sizes; and 4) isoform-specific apo(a) levels (ISLs), the amount of Lp(a) carried by an individual apo(a) isoform. Trait heritability was estimated by mid-parent-offspring analysis. The ethnicity-adjusted heritability estimate for Lp(a) level was 0.95. Heritability for ISLs corresponding to the smaller LPA allele in a given allele-pair was higher than that corresponding to the larger LPA allele (0.91 vs. 0.59, P = 0.017). Although not statistically different, heritability for both apo(a) isoforms (0.90 vs. 0.70) and LPA alleles (0.98 vs. 0.82) was higher for the smaller versus larger sizes. Heritability was generally lower in African-Americans versus Caucasians with a 4-fold difference for the larger LPA allele (0.25 vs. 0.94, P = 0.001). In Caucasians, an overall higher heritability pattern was noted for the older (≥47 years) versus younger (<47 years) families. In conclusion, Lp(a) level and traits associated with the smaller LPA alleles were strongly determined by genetics, although with a varying ethnic influence. Ethnic differences in heritability of the larger LPA allele warrant further investigations.