scholarly journals Lipoprotein(a)—The Crossroads of Atherosclerosis, Atherothrombosis and Inflammation

Biomolecules ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 26
Author(s):  
Sabina Ugovšek ◽  
Miran Šebeštjen
Keyword(s):  
Ethnic Diversity ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Dominant Mode ◽  
Lipoprotein A ◽  
Intravascular Thrombosis ◽  
Apolipoprotein A ◽  
Artery Disease ◽  
Factor Α ◽  
Inflammatory Macrophages

Increased lipoprotein(a) (Lp(a)) levels are an independent predictor of coronary artery disease (CAD), degenerative aortic stenosis (DAS), and heart failure independent of CAD and DAS. Lp(a) levels are genetically determinated in an autosomal dominant mode, with great intra- and inter-ethnic diversity. Most variations in Lp(a) levels arise from genetic variations of the gene that encodes the apolipoprotein(a) component of Lp(a), the LPA gene. LPA is located on the long arm of chromosome 6, within region 6q2.6–2.7. Lp(a) levels increase cardiovascular risk through several unrelated mechanisms. Lp(a) quantitatively carries all of the atherogenic risk of low-density lipoprotein cholesterol, although it is even more prone to oxidation and penetration through endothelia to promote the production of foam cells. The thrombogenic properties of Lp(a) result from the homology between apolipoprotein(a) and plasminogen, which compete for the same binding sites on endothelial cells to inhibit fibrinolysis and promote intravascular thrombosis. LPA has up to 70% homology with the human plasminogen gene. Oxidized phospholipids promote differentiation of pro-inflammatory macrophages that secrete pro-inflammatory cytokines (e. g., interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor-α). The aim of this review is to define which of these mechanisms of Lp(a) is predominant in different groups of patients.

PCSK9 inhibition with alirocumab reduces lipoprotein(a) levels in nonhuman primates by lowering apolipoprotein(a) production rate

2018 ◽  
Vol 132 (10) ◽  
pp. 1075-1083 ◽  
Author(s):  
Mikaël Croyal ◽  
Thi-Thu-Trang Tran ◽  
Rose Hélène Blanchard ◽  
Jean-Christophe Le Bail ◽  
Elise F. Villard ◽  
...  
Keyword(s):  
Production Rate ◽  
Nonhuman Primates ◽  
Numerical Models ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Human Hepatocytes ◽  
Lipoprotein A ◽  
Apolipoprotein A ◽  
Pcsk9 Inhibition

Therapeutic antibodies targeting proprotein convertase subtilisin kexin type 9 (PCSK9) (e.g. alirocumab) lower low-density lipoprotein cholesterol (LDL-C) and lipoprotein (a) [Lp(a)] levels in clinical trials. We recently showed that PCSK9 enhances apolipoprotein(a) [apo(a)] secretion from primary human hepatocytes but does not affect Lp(a) cellular uptake. Here, we aimed to determine how PCSK9 neutralization modulates Lp(a) levels in vivo. Six nonhuman primates (NHP) were treated with alirocumab or a control antibody (IgG1) in a crossover protocol. After the lowering of lipids reached steady state, NHP received an intravenous injection of [2H3]-leucine, and blood samples were collected sequentially over 48 h. Enrichment of apolipoproteins in [2H3]-leucine was assessed by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Kinetic parameters were calculated using numerical models with the SAAMII software. Compared with IgG1, alirocumab significantly reduced total cholesterol (TC) (−28%), LDL-C (−67%), Lp(a) (−56%), apolipoprotein B100 (apoB100) (−53%), and apo(a) (−53%). Alirocumab significantly increased the fractional catabolic rate of apoB100 (+29%) but not that of apo(a). Conversely, alirocumab sharply and significantly reduced the production rate (PR) of apo(a) (−42%), but not significantly that of apoB100, compared with IgG1, respectively. In line with the observations made in human hepatocytes, the present kinetic study establishes that PCSK9 neutralization with alirocumab efficiently reduces circulating apoB100 and apo(a) levels by distinct mechanisms: apoB primarily by enhancing its catabolism and apo(a) primarily by lowering its production.

scholarly journals Potent lipoprotein(a) lowering following apolipoprotein(a) antisense treatment reduces the pro-inflammatory activation of circulating monocytes in patients with elevated lipoprotein(a)

2020 ◽  
Vol 41 (24) ◽  
pp. 2262-2271 ◽  
Author(s):  
Lotte C A Stiekema ◽  
Koen H M Prange ◽  
Renate M Hoogeveen ◽  
Simone L Verweij ◽  
Jeffrey Kroon ◽  
...  
Keyword(s):  
Gene Expression ◽  
Ex Vivo ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cvd Risk ◽  
Inflammatory Gene Expression ◽  
Lipoprotein A ◽  
Inflammatory Gene ◽  
Apolipoprotein A ◽  
Inflammatory Activation

Abstract Aims Elevated lipoprotein(a) [Lp(a)] is strongly associated with an increased cardiovascular disease (CVD) risk. We previously reported that pro-inflammatory activation of circulating monocytes is a potential mechanism by which Lp(a) mediates CVD. Since potent Lp(a)-lowering therapies are emerging, it is of interest whether patients with elevated Lp(a) experience beneficial anti-inflammatory effects following large reductions in Lp(a). Methods and results Using transcriptome analysis, we show that circulating monocytes of healthy individuals with elevated Lp(a), as well as CVD patients with increased Lp(a) levels, both have a pro-inflammatory gene expression profile. The effect of Lp(a)-lowering on gene expression and function of monocytes was addressed in two local sub-studies, including 14 CVD patients with elevated Lp(a) who received apolipoprotein(a) [apo(a)] antisense (AKCEA-APO(a)-LRx) (NCT03070782), as well as 18 patients with elevated Lp(a) who received proprotein convertase subtilisin/kexin type 9 antibody (PCSK9ab) treatment (NCT02729025). AKCEA-APO(a)-LRx lowered Lp(a) by 47% and reduced the pro-inflammatory gene expression in monocytes of CVD patients with elevated Lp(a), which coincided with a functional reduction in transendothelial migration capacity of monocytes ex vivo (−17%, P < 0.001). In contrast, PCSK9ab treatment lowered Lp(a) by 16% and did not alter transcriptome nor functional properties of monocytes, despite an additional reduction of 65% in low-density lipoprotein cholesterol (LDL-C). Conclusion Potent Lp(a)-lowering following AKCEA-APO(a)-LRx, but not modest Lp(a)-lowering combined with LDL-C reduction following PCSK9ab treatment, reduced the pro-inflammatory state of circulating monocytes in patients with elevated Lp(a). These ex vivo data support a beneficial effect of large Lp(a) reductions in patients with elevated Lp(a).

scholarly journals Galactose-specific asialoglycoprotein receptor is involved in lipoprotein (a) catabolism

2003 ◽  
Vol 376 (3) ◽  
pp. 765-771 ◽  
Author(s):  
Andelko HRZENJAK ◽  
Sasa FRANK ◽  
Xingde WO ◽  
Yonggang ZHOU ◽  
Theo van BERKEL ◽  
...  
Keyword(s):  
Physiological Function ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Asialoglycoprotein Receptor ◽  
Fractional Catabolic Rate ◽  
Wild Type ◽  
Lipoprotein A ◽  
Apolipoprotein A ◽  
Catabolic Rate ◽  
First Time

Lp(a) [lipoprotein (a)] is a highly atherogenic plasma lipoprotein assembled from low-density lipoprotein and the glycoprotein apolipoprotein (a). The rate of Lp(a) biosynthesis correlates significantly with plasma Lp(a) concentrations, whereas the fractional catabolic rate does not have much influence. So far, little is known about Lp(a) catabolism. To study the site and mode of Lp(a) catabolism, native or sialidase-treated Lp(a) was injected into hedgehogs or ASGPR (asialoglycoprotein receptor)-knockout (ASGPR−) mice or wild-type (ASGPR+) mice, and the decay of the plasma Lp(a) concentration was followed. COS-7 cells were transfected with high- (HL-1) and low-molecular-mass ASGPR subunits (HL-2), and binding and degradation of intact or desialylated Lp(a) were measured. In hedgehogs, one of the few species that synthesize Lp(a), most of the Lp(a) was taken up by the liver, followed by kidney and spleen. Lp(a) and asialo-Lp(a) were catabolized with apparent half-lives of 13.8 and 0.55 h respectively. Asialo-orosomucoide increased both half-lives significantly. In mice, the apparent half-life of Lp(a) was 4–6 h. Catabolism of native Lp(a) by wild-type mice was significantly faster compared with ASGPR− mice and there was a significantly greater accumulation of Lp(a) in the liver of ASGPR+ mice compared with ASGPR− mice. The catabolism of asialo-Lp(a) in ASGPR− mice was 8-fold faster when compared with native Lp(a) in wild-type mice. Transfected COS-7 cells expressing functional ASGPR showed approx. 5-fold greater binding and 2-fold faster degradation of native Lp(a) compared with control cells. Our results for the first time demonstrate a physiological function of ASGPR in the catabolism of Lp(a).

scholarly journals Resistance of lipoprotein(a) to lipid peroxidation induced by oxygenated free radicals produced by γ radiolysis: a comparison with low-density lipoprotein

1996 ◽  
Vol 314 (1) ◽  
pp. 277-284 ◽  
Author(s):  
Jean-Louis BEAUDEUX ◽  
Monique GARDES-ALBERT ◽  
Jacques DELATTRE ◽  
Alain LEGRAND ◽  
François ROUSSELET ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Free Radicals ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Peroxyl Radicals ◽  
Low Density ◽  
Lipoprotein A ◽  
Acetylneuraminic Acid ◽  
Paired Samples ◽  
Apolipoprotein A

Lipid peroxidation of lipoprotein(a) [Lp(a)] by defined oxygen-centred free radicals (O2-· /OH·, O2-·, O2-· /HO2·) produced by γ radiolysis was compared with that of paired samples of low-density lipoprotein (LDL). Lp(a) appeared to be more resistant to oxidation than LDL, as indicated by the kinetic study of four markers of lipid peroxidation: decrease in vitamin E, formation of conjugated dienes and aldehydic products, and modification of electrophoretic mobility. In contrast, similar kinetics of lipid peroxidation were obtained for LDL and Lp(a-), which is the lipoparticle issued following the reductive cleavage of apolipoprotein(a) from Lp(a), thus suggesting that the greater resistance of Lp(a) to lipid peroxidation was due to the presence of apolipoprotein(a). Lipid peroxidation of Lp(a) and LDL induced by peroxyl radicals, which were produced by an azo compound [2,2′-azobis-(2-amidinopropane)dihydrochloride], confirmed both the resistance of Lp(a) to lipid peroxidation and the propensity of Lp(a-) to exhibit a greater susceptibility to oxidation than intact Lp(a). Our findings also indicated that the high content of apolipoprotein(a) in N-acetylneuraminic acid residues was only partly responsible for the resistance of Lp(a) to oxidation.

The NHLBI Twin Study: heritability of apolipoprotein A-I, B, and low density lipoprotein subclasses and concordance for lipoprotein(a)

1991 ◽  
Vol 91 (1-2) ◽  
pp. 97-106 ◽  
Author(s):  
Stefania Lamon-Fava ◽  
Dolores Jimenez ◽  
Joe C. Christian ◽  
Richard R. Fabsitz ◽  
Terry Reed ◽  
...  
Keyword(s):  
Twin Study ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Lipoprotein A ◽  
Lipoprotein Subclasses ◽  
Apolipoprotein A

Analysis of strneture–fonction relationships in human apolipoprotein(a)

1994 ◽  
Vol 72 (3) ◽  
pp. 304-310 ◽  
Author(s):  
Ytje Y. van der Hoek ◽  
John J. P. Kastelein ◽  
Marlys L. Koschinsky
Keyword(s):  
Recombinant Expression ◽  
Low Density Lipoprotein ◽  
Expression System ◽  
Density Lipoprotein ◽  
Site Directed Mutagenesis ◽  
Human Populations ◽  
Low Density ◽  
Covalent Linkage ◽  
Lipoprotein A ◽  
Apolipoprotein A

Elevated levels of lipoprotein(a) (Lp(a)) have been strongly correlated with the development of atherosclerosis in human populations. Lp(a) is distinguishable from low density lipoprotein by the presence of the unique protein component apolipoprotein(a) (apo(a)), which contains repeated domains that closely resemble that of plasminogen kringle IV. Using human embryonic kidney cells, we have expressed a recombinant form of apo(a) (r-apo(a)) containing 17 kringle IV-like domains. We have utilized this recombinant expression system to study the assembly of Lp(a) particles. We have demonstrated that Lp(a) particles containing r-apo(a) can be assembled extracellularly in plasma by covalent linkage to low density lipoprotein. Using site-directed mutagenesis, we have demonstrated that a cysteine residue present at position 4057 of the apo(a) protein (i.e., in the penultimate kringle IV repeat) mediates this covalent linkage. Using polymerase chain reaction amplification of liver apo(a) complementary DNA, we have demonstrated the presence of a polymorphism in apo(a) kringle IV type 10, which results in the substitution of a threonine for a methionine. Preliminary studies indicate that the presence of a threonine at this position may enhance the interaction of Lp(a) with lysine–Sepharose.Key words: apolipoprotein(a), lipoprotein(a), kringles, lipoprotein(a) assembly, polymorphism.

Structural and functional polymorphism of lipoprotein(a): biological and clinical implications

1995 ◽  
Vol 41 (1) ◽  
pp. 170-172 ◽  
Author(s):  
A M Scanu
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
The Other ◽  
Clinical Implications ◽  
Low Density ◽  
Functional Polymorphism ◽  
Lipoprotein A ◽  
Apolipoprotein A ◽  
Binding Function

Abstract Lipoprotein(a) [Lp(a)], a variant of low-density lipoprotein, is heterogeneous in density because of variability in the content and composition of its core lipids and size polymorphism of its specific glycoprotein component, apolipoprotein(a) [apo(a)]. In some individuals, density polymorphism may also derive from the fact that Lp(a) contains 2 mol of apo(a) per mole of apoB100, contrary to the more common 1:1 molar stoichiometry. Moreover, the size of apo(a) is polymorphic because of variations in the number of kringle 4 type 2 repeats. Another type of apo(a) polymorphism is related to sequence mutations at the kringle level. Two mutations can occur in kringle 4 type 10: one, Trp72-->Arg, is affiliated with an Lp(a) that is lysine-binding defective; the other, Met66-->Thr, with a normal lysine-binding function. Thus, Lp(a) is structurally and functionally polymorphic, a notion that must be considered in assessing the cardiovascular pathogenicity of this lipoprotein variant and in immunoquantification assays.

Low-density lipoprotein (LDL), which includes apolipoprotein A-I (apoAI-LDL) as a novel marker of coronary artery disease

2008 ◽  
Vol 397 (1-2) ◽  
pp. 42-47 ◽  
Author(s):  
Ken Ogasawara ◽  
Shinichi Mashiba ◽  
Hideki Hashimoto ◽  
Shiho Kojima ◽  
Shunsuke Matsuno ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Apolipoprotein A ◽  
Artery Disease

Quantification of lipoprotein(a) particles containing various apolipoprotein(a) isoforms by a monoclonal anti-apo(a) capture antibody and a polyclonal anti-apolipoprotein B detection antibody sandwich enzyme immunoassay

1993 ◽  
Vol 39 (7) ◽  
pp. 1382-1389 ◽  
Author(s):  
W C Taddei-Peters ◽  
B T Butman ◽  
G R Jones ◽  
T M Venetta ◽  
P F Macomber ◽  
...  
Keyword(s):  
Apolipoprotein B ◽  
Low Density Lipoprotein ◽  
Sandwich Elisa ◽  
Density Lipoprotein ◽  
Low Density ◽  
Linear Calibration ◽  
Lipoprotein A ◽  
Apolipoprotein A ◽  
Assay Format ◽  
Capture Antibody

Abstract A quantitative sandwich ELISA for lipoprotein(a) [Lp(a)], utilizing a monoclonal capture antibody that recognizes human and rhesus monkey apolipoprotein(a) [apo(a)] isoforms in combination with a polyclonal anti-apolipoprotein B-peroxidase conjugate was developed. This assay generates a linear calibration curve from 31.2 to 1000 mg/L, is highly reproducible (intra- and interassay CV of < 5% and < or = 12%, respectively), and shows no interference from plasminogen (1 g/L), low-density lipoprotein (6.00 g/L), triglycerides (27.00 g/L from chylomicrons and 10.00 g/L from very-low-density lipoprotein), hemoglobin (5 g/L), or bilirubin (30 mg/L). This assay format quantifies the concentration of Lp(a) on an equal molar basis regardless of apo(a) isoform. In contrast, a commercially available ELISA [Macra Lp(a)] method with a monoclonal anti-apo(a) capture antibody and a polyclonal anti-apo(a) conjugate was found to underestimate the Lp(a) concentrations of individuals with lower-M(r) apo(a) isoforms--whether quantifying the Lp(a) in plasma or the purified lipoprotein. This demonstrates the importance of assay format selection in quantifying Lp(a).

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