Advances in dyslipidemia management for prevention of atherosclerosis: PCSK9 monoclonal antibody therapy and beyond

Genetic or therapeutic neutralization of ALK1 reduces LDL transcytosis and atherosclerosis in mice

Low-density lipoprotein (LDL) accumulation in the arterial wall contributes to atherosclerosis initiation and progression1. Activin A receptor-like type 1 (ACVRL1, called activin-like kinase receptor (ALK1)) is a recently identified receptor that mediates LDL entry and transcytosis in endothelial cells (ECs)2,3. However, the role of this pathway in vivo is not yet known. In the present study, we show that genetic deletion of ALK1 in arterial ECs of mice substantially limits LDL accumulation, macrophage infiltration and atherosclerosis without affecting cholesterol or triglyceride levels. Moreover, a selective monoclonal antibody binding ALK1 efficiently blocked LDL transcytosis, but not bone morphogenetic protein-9 (BMP9) signaling, dramatically reducing plaque formation in LDL receptor knockout mice fed a high-fat diet. Thus, our results demonstrate that blocking LDL transcytosis into the endothelium may be a promising therapeutic strategy that targets the initiating event of atherosclerotic cardiovascular disease.

Blood lipid levels and treatment following an acute coronary syndrome or coronary intervention – Journey from hospital to cardiac rehabilitation

Background

A significant number of coronary artery disease patients do not attain guideline recommended LDL levels. Participating in a cardiac rehabilitation (CR) program has been shown to improve adherence to medical therapy.

Objectives

Evaluate the specific lipid lowering therapy (LLT) prescribed and percent of subjects achieving LDL levels of <70 mg/dL before and after 3 months following CR program initiation.

Methods

From May 2017 to April 2019, we prospectively recruited patients referred to our CR program and compared 1015 of them at 4 time points; (P1) just prior to the index hospitalization, (P2) during the index hospitalization, (P3) upon entering the CR program, roughly 3 months after the index hospitalization, and (P4) 3 months into the CR program. Included in the analysis were parameters of lipid levels, the dispensed medication given, as well as patient adherence to treatment. Results: At CR intake, LDL goals were partially achieved with 57% of patients below 70 mg/dL. After completion of 3 months of CR, 63% of patients had LDL levels below 70 mg/dL, despite the fact that the majority (95%) were prescribed high-dose potent statins. Aside from the LDL levels at CR intake, we found no other independent predictors for not attaining the lipid goals at 6 months.

Conclusions

A significant treatment gap is present even in a selected population participating in CR, with the vast majority receiving guideline recommended LLT. In order to improve goals, we need to intensify LLT treatment, and increase patient adherence to therapy.

Glucocorticoid induced TNF receptor family-related protein (GITR) - A novel driver of atherosclerosis

Atherosclerosis is a lipid-driven, chronic inflammatory disease. In spite of efficient lipid lowering treatments, such as statins and PCSK9 inhibitors, patients, especially those with elevated inflammatory biomarkers, still have a significant residual cardiovascular disease risk. Novel drugs targeting inflammatory mediators are needed to further reduce this residual risk. Agonistic immune checkpoint proteins, including CD86, CD40L and CD40, have been shown to be drivers of atherosclerosis. Recently, glucocorticoid-induced tumour necrosis factor receptor family-related protein (GITR), a co-stimulatory immune checkpoint protein, was identified to be pivotal in cardiovascular disease. Cardiovascular patients have elevated soluble GITR plasma levels compared to healthy controls. Furthermore, in human carotid endarterectomy plaques, GITR expression was higher in plaques from symptomatic compared to asymptomatic patients and correlated with features of plaque vulnerability. Moreover, depleting GITR reduced atherosclerotic plaque development in mice. GITR-deficient monocytes and macrophages exhibited less inflammatory potential and reduced migratory capacity. In this review, we discuss GITR's effects on various immune cells, mechanisms, signalling pathways and finally GITR's potential as a novel drug target in atherosclerosis.

Hepatocrinology

Hepatocrinology is defined as a bidirectional, complex relationship between hepatic physiology and endocrine function, hepatic disease and endocrine dysfunction, hepatotropic drugs and endocrine function, and endocrine drugs and hepatic health. The scope of hepatocrinology includes conditions of varied etiology (metabolic, infectious, autoimmune, and invasive) that we term as hepato-endocrine syndromes. This perspective shares the definition, concept, and scope of hepatocrinology and shares insight related to this aspect of medicine. It is hoped that this communication will encourage further attention and research in this critical field.

Targeted anti-inflammatory therapy is a new insight for reducing cardiovascular events: A review from physiology to the clinic

Despite considerable progressions, cardiovascular disease (CVD) is still one of the major causes of mortality around the world, indicates an important and unmet clinical need. Recently, extensive studies have been performed on the role of inflammatory factors as either a major or surrogate factor in the pathophysiology of CVD. Epidemiological observations suggest the theory of the role of inflammatory mediators in the development of cardiovascular events. This may support the idea that targeted anti-inflammatory therapies, on the background of traditional validated medical therapies, can play a significant role in prevention and even reduction of cardiovascular disorders. Many randomized controlled trials have shown that drugs commonly useful for primary and secondary prevention of CVD have an anti-inflammatory mechanism. Further, many anti-inflammatory drugs are being examined because of their potential to reduce the risk of cardiovascular problems. In this study, we review the process of inflammation in the development of cardiovascular events, both in vivo and clinical evidence in immunotherapy for CVD.

A novel variant in LPL gene is associated with familial combined hyperlipidemia

Familial combined hyperlipidemia (FCHL) is a common genetic disorder characterized by increased fasted serum cholesterol, triglycerides, and apolipoprotein B-100. Molecular genetic techniques such as next generation sequencing have been very successful methods for rare variants finding with a moderate-to large effect. In this study, we characterized a large pedigree from MASHAD study in northeast Iran with coinheritance of FCHL and early-onset coronary heart disease. In this family, we used whole-exome sequencing and Sanger sequencing to determine the disease-associated gene. We identified a novel variant in the LPL gene, leading to a substitution of an asparagine for aspartic acid at position 151. The D151N substitution cosegregated with these characters in all affected family members in the pedigree but it was absent in all unaffected members in this family. We speculated that the mutation D151N in LPL gene might be associated with FCHL and early-onset coronary heart disease in this family. However, the substantial mechanism requires further investigation.

Self-Albumin Camouflage of Carrier Protein Prevents Nontarget Antibody Production for Enhanced LDL-C Immunotherapy

Elevated low-density lipoprotein cholesterol (LDL-C) increases the risk of atherosclerotic cardiovascular disease. Peptide-based PCSK9 vaccines have shown a promising prospect of reducing LDL-C. In peptide vaccine (pVax) design, the peptide antigens need to conjugate with carrier protein (CP). However, CP incorporation can induce undesirable anti-CP antibodies, which sterically mask peptide epitopes from being recognized by specific B cells and impair subsequent therapeutically antibody production. This epitopic suppression has posed a barrier in clinical translation of conjugate vaccines all along. A model CP (keyhole limpet hemocyanin, KLH) is herein camouflaged with serum albumin (SA) into hybrid nanocarriers (SA@N), with PCSK9 peptide being anchored onto the surface to form nanovaccine (SA@NVax). Such camouflage of KLH via high "self" SA coverage is able to inhibit KLH from extracellular immune recognition and prevent detectable anti-KLH antibody production. Furthermore, the nanovaccine around 70 nm stabilized by intermolecular disulfide network is ideal for internalization and biodegradation by antigen presenting cells as well as better retention in draining lymph nodes and spleen. As expected, the SA@NVax efficiently primes higher anti-PCSK9 IgG antibody titer than PCSK9 pVax.

Laboratory Testing in the Context of Biologics and Cellular Therapies

"With the increasing application of biotechnology to the realm of pharmacology and therapeutics, the types of biological treatments available have significantly expanded. Currently, recombinant proteins, humanized antibodies, or rationally engineered monoclonal antibodies are used on a regular basis in the clinical setting. Moreover, cell-based therapeutics with molecularly rewired antigenic specificities are becoming increasingly common in oncology and are actively being developed for a broad range of diseases. Nonetheless, there has been a significant lag between the development of these technologies and the emergence of assays that can monitor these novel interventions."

Pragmatic Analysis of Dyslipidemia Involvement in Coronary Artery Disease: A Narrative Review

Background

Dyslipidemia is the main factor involved in the occurrence and progression of coronary artery disease.

Objective

The research strategy is aimed at analyzing new data on the pathophysiology of dyslipidemia involvement in coronary artery disease, the modalities of atherogenic risk estimation and therapeutic advances.

Methods

Scientific articles published in PubMed from January 2017 to February 2018 were searched using the terms “dyslipidemia” and “ischemic heart disease”.

Results

PCSK9 contributes to the increase in serum levels of low-density lipoprotein-cholesterol and lipoprotein (a). The inflammation is involved in the progression of hyperlipidemia and atherosclerosis. Hypercholesterolemia changes the global cardiac gene expression profile and is thus involved in the increase of oxidative stress, mitochondrial dysfunction, and apoptosis initiated by inflammation. Coronary artery calcifications may estimate the risk of coronary events. The cardio-ankle vascular index evaluates the arterial stiffness and correlates with subclinical coronary atherosclerosis. The carotid plaque score is superior to carotid intima-media thickness for risk stratification in patients with familial hypercholesterolemia and both can independently predict coronary artery disease. The lipoprotein (a) and familial hypercholesterolemia have a synergistic role in predicting the risk of early onset and severity of coronary atherosclerosis. A decrease in atherosclerotic coronary plaque progression can be achieved in patients with plasma LDL-cholesterol levels below 70 mg/dL. A highly durable RNA interference therapeutic inhibitor of PCSK9 synthesis could be a future solution.

Conclusion

The prophylaxis and treatment of coronary artery disease in a dyslipidemic patient should be based on a careful assessment of cardio-vascular risk factors and individual metabolic particularities, so it may be personalized.

Interpreting the Findings From the Recent PCSK9 Monoclonal Antibody Cardiovascular Outcomes Trials

The recent development of monoclonal antibodies targeted to proprotein convertase subtilisin/kexin type 9 (PCSK9), e.g., PCSK9 inhibitors has revolutionized the landscape of lipid management. Many clinical trials assessing this class have demonstrated remarkable and consistent reductions in low-density lipoprotein-cholesterol. Moreover, the GLAGOV trial demonstrated the efficacy of evolocumab, when added to statin therapy, in reducing the progression of atherosclerosis measured by serial intravascular ultrasound, with the first suggestion of continued benefit down to LDL-C levels of 0.5 mmol/L (20 mg/dL). This trial was followed by the FOURIER Cardiovascular Outcomes trial in more than 27,000 patients with stable atherosclerotic cardiovascular disease (ASCVD) where evolocumab reduced the primary endpoint of atherosclerotic events by 15%, without significant safety differences between treatment groups. Furthermore, subgroup analyses suggested greater benefits seen in those with longer exposure to evolocumab recent acute coronary syndrome, multiple myocardial infarctions, multivessel coronary artery disease, peripheral arterial disease, as well as the subgroup who achieved very low low-density lipoprotein-cholesterol levels of below 0.3 mmol/L (10 mg/dL). Moreover, the EBBINGHAUS substudy demonstrated no differences in objectively measured cognitive function between treatment groups. The SPIRE 2 trial evaluating bococizumab in high-risk patients with baseline LDL-C ≥2.6 mmol/L (100 mg/dL) demonstrated significant atherosclerotic risk reduction, but the trial and further development of the drug was prematurely discontinued due to substantial attenuation of the LDL-C effect over time due to the development of neutralizing antibodies. Finally, the ODYSSEY Cardiovascular Outcomes trial testing alirocumab in subjects with recent (<1 year) acute coronary syndrome demonstrated a 15% relative risk reduction in the primary composite outcome, as well as a significant reduction in total mortality. Greater benefits were noted in those whose LDL-C at baseline was 2.6 mmol/L (100 mg/dL) or greater. These trials collectively demonstrate the added efficacy of PCSK9 inhibitors over moderate and high-intensity statin therapy for unprecedented low-density lipoprotein-cholesterol reduction and incremental ASCVD risk reduction.

Treatment Strategy for Dyslipidemia in Cardiovascular Disease Prevention: Focus on Old and New Drugs

Prevention and treatment of dyslipidemia should be considered as an integral part of individual cardiovascular prevention interventions, which should be addressed primarily to those at higher risk who benefit most. To date, statins remain the first-choice therapy, as they have been shown to reduce the risk of major vascular events by lowering low-density lipoprotein cholesterol (LDL-C). However, due to adherence to statin therapy or statin resistance, many patients do not reach LDL-C target levels. Ezetimibe, fibrates, and nicotinic acid represent the second-choice drugs to be used in combination with statins if lipid targets cannot be reached. In addition, anti-PCSK9 drugs (evolocumab and alirocumab) provide an effective solution for patients with familial hypercholesterolemia (FH) and statin intolerance at very high cardiovascular risk. Recently, studies demonstrated the effects of two novel lipid-lowering agents (lomitapide and mipomersen) for the management of homozygous FH by decreasing LDL-C values and reducing cardiovascular events. However, the costs for these new therapies made the cost–effectiveness debate more complicated.

Post-transcriptional Regulation of PCSK9 by miR-191, miR-222, and miR-224

Since proprotein convertase subtilisin kexin 9 (PCSK9) discovery, a gene involved in LDL metabolism regulation and cardiovascular diseases (CVD), many therapeutic strategies have been introduced for direct targeting of PCSK9. The main goal of these strategies has been to reduce PCSK9 protein level either by application of antibodies or inhibition of its production. In this study, we have tried to discover microRNAs (miRNAs) which can target, and hence regulate, PCSK9 expression. Using bioinformatics tools, we selected three microRNAs with binding sites on 3′-UTR of PCSK9. The expression level of these miRNAs was examined in three different cell lines using real-time RT-PCR. We observed a reciprocal expression pattern between expression level of miR-191, miR-222, and miR-224 with that of PCSK9. Accordingly, the expression levels were highest in Huh7 cells which expressed the lowest level of PCSK9, compared to HepG2 and A549 cell lines. PCSK9 mRNA level also showed a significant decline in HepG2 cells transfected with the vectors overexpressing the aforementioned miRNAs. Furthermore, the miRNAs target sites were cloned in psiCHECK-2 vector, and a direct interaction of the miRNAs and the PCSK9 3′-UTR putative target sites was investigated by means of luciferase assay. Our findings revealed that miR-191, miR-222, and miR-224 can directly interact with PCSK9 3′-UTR and regulate its expression. In conclusion, our data introduces a role for miRNAs to regulate PCSK9 expression.

Trends in cardiovascular risk factors among U.S. men and women with and without diabetes, 1988-2014

Background

Studies evidenced that reduction in cardiovascular disease (CVD) mortality in diabetic patients can be attributed to improvements in major CVD risk factors and evidence-based treatments. Furthermore, studies showed that the relative risk of CVD mortality associated with diabetes compared with non-diabetes is stronger in women than in men. Hence, we aimed to examine trends in CVD risk factors and intervention measures by sex and diabetic status.

Methods

Analysis of 5 distinct cross-sectional National Health and Nutrition Examination Surveys, 1988–1994, 1999–2002, 2003–2006, 2007–2010, and 2010–2014. Since detailed information on nontraditional risk factors such as sleep apnea was not available in each NHANES survey, traditional CVD risk factors including obesity, hypertension, and dyslipidemia were assessed in the study. To assess whether changes throughout the 27-year period differed by diabetes status, a logistic regression analysis was utilized to examine potential interaction effects between survey and diabetes. The similar process was repeated for sex.

Results

Means of all risk factors except body mass index and waist circumference decreased and the prevalence of antihypertensive and lipid-lowering medication use increased over time among diabetic and non-diabetic men and women. For both men and women, survey × diabetes status interaction terms for changes in HDL-cholesterol and triglyceride levels were not statistically significant, while the prevalence of antihypertensive and lipid-lowering medication use increased more in diabetic than in non-diabetic persons (all P < 0.001). For women, survey × diabetes status interaction terms indicated that compared with the first survey, total cholesterol, LDL-cholesterol, and non-HDL-cholesterol fallen more in diabetic than in non-diabetic persons (all P < 0.001). In the diabetic state, men experienced similar changes in means of all CVD risk factors and the prevalence of antihypertensive and lipid-lowering medication use as women (all P for interactions between survey and sex were >0.01).

Conclusions

The major traditional CVD risk factors in diabetic men decreased to the same extent that they did for non-diabetic men. The magnitude of changes in the favorable trends in diabetic women was of similar or greater compared with those among non-diabetic women. Diabetic women had as good an improvement in CVD risk factors as diabetic men.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4921-4) contains supplementary material, which is available to authorized users.