Welcome to the EAS 2022 Interactive Program

Background and Aims

Lipoprotein(a) is an apoB-containing lipoprotein attached to an apolipoprotein(a) and is causally associated with the risk of cardiovascular disease. Because the apo(a) moiety has sequence homology with plasminogen, Lp(a) may be prothrombotic. We therefore sought to determine whether Lp(a) has a clinically significant venous or arterial prothrombotic effect.

Methods

We used Mendelian randomization to evaluate the causal effect of Lp(a) on the risk of venous thromboembolism (VTE) among participants in the UK-Biobank. We then evaluated the causal effect of Lp(a) on the risk of myocardial infarction (MI) in the entire study sample, and stratified by genetic scores that mimic the effect of antiplatelet and antithrombin therapies.

Results

Among 445,774 participants (mean age 57.3 years, 54% female), a total of 15,973 had a VTE event, and 15,465 had a first MI. Lp(a) was not associated with the risk of VTE (OR: 0.99, 95%CI:0.96-1.02). By contrast, Lp(a) was strongly associated with the risk of MI (HR: 1.35 per 100 nmol/L higher Lp(a), 95%CI:1.32-1.38). Furthermore, the antiplatelet score was associated with a dose-dependent step-wise decrease in the risk of MI, and the antithrombin score was associated with a dose-dependent step-wise decrease in the risk of VTE. However, the effect of Lp(a) on the risk of MI was not diminished by either genetically determined lifelong platelet or thrombin inhibition (Figure).

Conclusions

Lp(a) does not have a clinically significant venous or arterial prothrombotic effect. Therefore, the increased risk of MI caused by elevated Lp(a) is unlikely to be reduced by treatment with either an antiplatelet or antithrombin therapy.

Background and Aims

Lp(a) increases the risk of atherosclerotic cardiovascular (CV) disease. Current guidelines suggest controlling other CV risk factors, such as LDL-C levels, more intensively in order to reduce the increased risk associated with elevated Lp(a). Therefore, to guide clinical management, we sought to evaluate the magnitude of LDL-C reduction needed to overcome the increased CV risk caused by Lp(a).

Methods

A total of 445,744 UK-Biobank participants were included in the study (mean age: 57.3 years; female sex: 54.3%). We plotted the trajectories of the lifetime risk of major coronary events (a composite of fatal or non-fatal myocardial infarction, or coronary revascularization) associated with increased Lp(a) levels and the equivalent changes in LDL-C levels required to overcome the increased risk caused by various Lp(a) levels.

Results

Our results provide a quantitative estimate of how much LDL-C must be reduced to overcome the increased risk specifically caused by any level of Lp(a). In the table the LDL-C reduction needed to overcome the increased risk caused by Lp(a) is reported based on Lp(a) levels and the age at which LDL-C lowering is started. Notably, the magnitude of LDL-C reduction needed to overcome the increased risk caused by Lp(a) increases with the age at which LDL-C lowering is initiated.

Conclusions

Although no therapies lower Lp(a) specifically, the increased risk caused by Lp(a) can be overcome with additional LDL-C lowering that depends on a person’s Lp(a) level and the age at which LDL-C lowering is started. Our results provide practical guidance for managing increased CV risk caused by Lp(a).

Background and Aims

miR-148a is a hepatic and immune enriched miRNA that regulates lipoprotein metabolism and macrophage cholesterol homeostasis and inflammation. We have characterized miR-148a as a negative regulator of LDLR expression and activity. Moreover, we have demostrated that miR-148a regulates hepatic ABCA1 expression and circulating HDL-C levels. In addition to the regulation of circulating cholesterol, miR-148a is highly expressed in macrophages, which regulate cholesterol efflux and inflammation. We hypothesize that antagonism of miR-148a might attenuate the progression of atherosclerosis by decreasing circulating LDL-C, increasing plasma HDL-C levels, promoting macrophage cholesterol efflux and attenuating macrophage pro-inflammatory response

Methods

APOB^TGApobec^-/-Ldlr ^+/- mice were fed a Western diet for 22 weeks and injected with a non-targeting locked nucleic acid (LNA; LNA control) or miR-148a LNA (LNA 148a) for the last 10 weeks. At the end of the treatment, mice were sacrificed and circulating lipids, hepatic gene expression and atherosclerotic lesions were analyzed.

Results

Examination of atherosclerotic lesions revealed a significant reduction of plaque size and a marked remodeling of the lesions towards a more stable phenotype. Mechanistically, we found that miR-148a levels influenced macrophage cholesterol efflux and inflammatory response. Suppression of miR-148a in mouse primary macrophages decreased mRNA levels of pro-inflammatory M1-like markers and reduced the expression of anti-inflammatory genes.

Conclusions

Therapeutic silencing of miR148a mitigates the progression of atherosclerosis and promotes plaque stability. The anti-atherogenic effect of miR-148a antisense therapy is likely mediated by the anti-inflammatory effects observed in macrophages treated with miR-148 LNA and independent of significant changes in circulating LDL-C and HDL-C.

Background and Aims

ANGPTL4 is an important regulator of plasma triglyceride levels and an attractive pharmacological target for lipid-lowering and reducing cardiovascular risk. Here we aimed to study the efficacy and safety of silencing ANGPTL4 in livers of mice using hepatocyte-targeting GalNAc-conjugated antisense oligonucleotides (ASOs).

Methods

C57Bl/6 mice were given high fat diet and injected with murine specific ANGPTL4-ASO to study the effects of hepatic target down-regulation.

Results

Compared to injections with negative control ASOs, four injections of two different doses of ANGPTL4 ASOs in two weeks effectively silenced hepatic Angptl4 gene and protein expression and significantly reduced plasma triglyceride in fed and fasted mice and reduced plasma glucose levels in fed mice. In separate experiments, injection of two different doses of ANGPTL4 ASOs during 20 weeks of high-fat feeding effectively reduced hepatic Angptl4 gene expression but did not trigger mesenteric lymphadenopathy, an acute phase response, chylous ascites, or any other pathological features. Compared to mice injected with negative control ASOs, mice injected with ANGPTL4 ASOs gained significantly less weight, showed reduced food intake, exhibited better glucose tolerance, and had lower plasma triglycerides, total cholesterol, LDL cholesterol, glucose, serum amyloid A, and liver triglyceride levels. By contrast, no significant difference in plasma alanine aminotransferase activity was observed.

Conclusions

Overall, these data indicate that ASOs targeting ANGPTL4 effectively reduce plasma triglyceride levels in mice without raising major safety concerns as has previously been seen with ANGPTL4-mAB treatment or whole body genetic knock-down in mice.

Background and Aims

Elevated plasma triglyceride is a marker of increased risk for cardiovascular disease and has been of interest for intensive drug development the last decade. Targets regulating the lipoprotein lipase system, such as ANGPTL3 and APOC3, have been in focus using different modalities, e.g. mAB and RNA based drugs. Recent genetetic studies using mendelian randomization, by us (unpublished) and others (published), suggests that ANGPTL4 is a far better target for both CAD and T2D than established targets ANGPTL3 and APOC3. Moreover, ANGPTL4 has also been linked to kidney function and liver fat content.

We have shown, using a murine ANGPTL4-ASO tool compouind, that ANGPTL4 could be a safe target (submitted data).

Here we aim showing the nonclinical safety profile of the human drug candidate A24110He.

Methods

A24110He is a drug candidate being developed for the treatment of Severe Hypertriglyceremia (SHTG) and Familiar
Chylomicronaemia Syndrome (FCS). A24110He is an antisense oligonucleotide targeting the mRNA of
Angiopoietin-like 4 (ANGPTL4) protein, which modulates triacylglycerol homeostasis through its inhibitory
effect on lipoprotein lipase (LPL) activity. A24110He was tested in vitro and in vivo for safety parameters and efficacy.

Results

A24110He was found to efficiently decrease ANGPTL4 mRNA in various human and animal cells. In vivo it was was well tolerated in mice, rats and cynomolgus monkey. Significant reduction on plasma triacylglycerol was seen both in rats and cynomolgus monkey.

Conclusions

In conclusion, the safety pharmacology studies indicate that A24110He will not cause any adverse effects at the doses intended to be used in a planned clinical trial.

Background and Aims

The ability to generate and respond to mechanical forces is a basic requirement for maintaining cell homeostasis. This is of particular importance for the cardiovascular system which is subjected to different mechanical forces such as Low and High shear stresses (LSS and HSS). Autophagy is involved in endothelial cells (ECs) response to HSS generated by blood flow. However, it is still unclear whether the variability of shear stress triggers specific autophagic response in ECs.

Methods

We used fluid flow chamber system to generate different mechanical forces on ECs in vitro and we specifically studied LSS and HSS artery territories, referred as aortic arch and descending aorta respectively, in mice susceptible to atherosclerosis.

Results

We found that LSS and HSS mobilize two different signalling modules relying on class II PI3K (PI3KCIIα) and III PI3K/Vps34 respectively to induce autophagy. We demonstrated that LSS-induced autophagy required the primary cilium and is critical to prevent ECs permeability and integrity. Accordingly, atherogenic stress or reduced PI3KCIIα expression led to a decrease in the ciliated ECs associated with decreased autophagic flux and accelerated plaque deposition in the LSS regions. Furthermore, we revealed that PI3KCIIα controls mTORC1 activation. Notably, mTORC1 inhibition impaired atherosclerosis development in ApoE^-/- PI3KCIIα^+/- mice and led to primary cilium restoration suggesting a crosstalk between primary cilium biogenesis and autophagy in LSS context.

Conclusions

Our data reveal that mechanical forces variability within arterial system determine ECs autophagic response and support a central role of PI3KCIIα/mTOR axis in EC mechanosensing in atheroprone regions.

Background and Aims

Methylation regulates gene expression of metalloprotease-9 (MMP-9) and tissue inhibitor of metalloprotease type 2 (TIMP-2) in acute coronary syndrome (ACS).

Methods

The methylation was induced by bisulfite treatment of two CpG rich islets in each gene (MMP9-1 et -2, TIMP2-1 et 2).

Results

Hypomethylation was shown in patients with ACS for MMP9-1 (-19%) but not for MMP9-2 (-6%), and was more important for TIMP2-1 (-41%) and 2 (-37%) in comparison to controls. Hypomethylation was not correlated to protein concentration of MMP-9 and TIMP-2 in blood plasma as measured by Elisa; nevertheless MMP-9 and TIMP-2 levels were in inversed correlation creating an unbalance favoring plaque erosion and detachment. Moreover, plasma MMP-9 increased in function of ACS severity (stable angina vs NSTEMI, NSTEMI vs STEMI), of the number of stenosed vessels (1, 2 or 3) and of the treatment by stent disposition and the type of stent.

Conclusions

Epigenetics studies could improve knowledge on the regulation of MMP and TIMP gene expression in function of severity of SCA for prediction of myocardial infarction at an early stage for better nursing.

Background and Aims

We have shown that ApoE-/- mice born to hypercholesterolemic ApoE-/- mothers develop more atherosclerotic plaques than ApoE-/- mice born to normocholesterolemic ApoE+/- mothers. We aimed to investigate the effect of treatment with a cholesterol-lowering drug in ApoE-/- mice during gestation only or during both gestation and lactation on the development of atherosclerosis in adult ApoE-/- offspring.

Methods

Three groups of ApoE-/- females were fed either control diet (CTR), a diet with 3% cholestyramine during gestation (CTY-G) or during gestation and lactation (CTY-GL). At 25 weeks of age, males and females offspring were sacrificed and the size of atherosclerotic plaques in the aortic roots was measured. Plasma cholesterol, triglycerides and bile acids concentrations were determined. MicroRNA expression in liver were analysed.

Results

A significant reduction in atherosclerotic plaque area was observed in male progeny of CTY-G and CTY-GL, at 600µm from the heart (p= 0.01 and p=0.02 respectively) and at 800µm. Plaque regression is also observed in females at 600 m for CTY-G (p=0,006) and at 800 μm for CTY-GL (p=0.03). Neither cholesterolemia nor triglyceridemia showed any significant difference between groups. In male CTY-GL offspring and female CTY-G and CTY-GL, significant increase in the plasma tauro-conjugated bile acids pools was noted (p=0.03, p=0.01 and p=0.04 respectively). Among analyzed microRNA, hepatic miR122 expression decreased significantly in male CTY-G and female CTY-GL (p=0.01).

Conclusions

Cholestyramine perinatal treatment decreases atherosclerosis development in offspring. This effect is independent of the cholesterol levels. The bile acids pools increase and mi-RNA 122 decrease could explain the protective effect of treatment.