Vaccines for cholesterol management

Potential use of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition and prevention method in viral infection

Cellular lipid membranes serve as the primary barrier preventing viral infection of the host cell and provide viruses with a critical initial point of contact. Occasionally, viruses can utilize lipids as viral receptors. Viruses depend significantly on lipid rafts for infection at virtually every stage of their life cycle. The pivotal role that proprotein convertase subtilisin/kexin Type 9 (PCSK9) plays in cholesterol homeostasis and atherosclerosis, primarily by post-transcriptionally regulating hepatic low-density lipoprotein receptor (LDLR) and promoting its lysosomal degradation, has garnered increasing interest. Conversely, using therapeutic, fully humanized antibodies to block PCSK9 leads to a significant reduction in high LDL cholesterol (LDL-C) levels. The Food and Drug Administration (FDA) has approved PCSK9 inhibitors, including inclisiran (Leqvio®), alirocumab (Praluent), and evolocumab (Repatha). At present, active immunization strategies targeting PCSK9 present a compelling substitute for passive immunization through the administration of antibodies. In addition to the current inquiry into the potential therapeutic application of PCSK9 inhibition in human immunodeficiency virus (HIV)-infected patients for hyperlipidemia associated with HIV and antiretroviral therapy (ART), preclinical research suggests that PCSK9 may also play a role in inhibiting hepatitis C virus (HCV) replication. Furthermore, PCSK9 inhibition has been suggested to protect against dengue virus (DENV) potentially and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses. Recent evidence regarding the impact of PCSK9 on a variety of viral infections, including HCV, HIV, DENV, and SARS-CoV-2, is examined in this article. As a result, PCSK9 inhibitors and vaccines may serve as viable host therapies for viral infections, as our research indicates that PCSK9 is significantly involved in the pathogenesis of viral infections.

A novel atheroprotective role of MF59-like adjuvant when co-administered with CETP vaccine in rabbit model of atherosclerosis

OBJECTIVES

In this study, for the first time, MF59 adjuvant was used to develop a cholesteryl ester transfer protein (CETP) vaccine. The efficacy of the vaccine was compared with the efficacy of CETP vaccine formulated with Alum/CpG, the formulation that its immunogenicity has been already demonstrated in rabbit and mice.

MATERIALS AND METHODS

Tetanus toxoid- CETP peptide (TT-CETP) was mixed with Alum/CpG or MF59-like and administered subcutaneously for total five times in rabbit model of atherosclerosis. Anti-TT-CETP specific antibody, CETP activity in sera and mRNA level of cytokine IL-4 and IFN-γ in peripheral mononuclear cells were determined. Therapeutic response was also examined by tracking serum lipoprotein levels and pathologic observation of atherosclerotic lesions at aortic site.

RESULTS

More anti-TT-CETP antibody was found in Alum/CpG vaccinated rabbits compared to buffer (P<0.001). Antibody induced by MF59-like formulation was not significantly higher than buffer. CETP activity and lipoprotein levels were not significantly different between vaccinated and control rabbits. The mRNA level of IL-4 was significantly lower than buffer while, IFN-γ gene expression was significantly higher in both vaccinated groups. Atherosclerosis thickness grade of aorta was dramatically lower than buffer (P<0.01) in both vaccinated groups.

CONCLUSION

It is concluded that MF59-adjuvanted CETP vaccine showed anti-atherosclerosis properties, but the protective effect could not be directly attributed to the immune response induced by anti TT-CETP antibody and CETP inhibition. Further studies are needed to explain the anti-atherosclerosis properties of MF59 in the presence of TT-CETP peptide.

Reality of a Vaccine in the Prevention and Treatment of Atherosclerosis

Atherosclerosis together with multiple sclerosis, psoriasis and rheumatoid arthritis can be used as examples of chronic inflammatory diseases associated with multifactorial components that evolve over the years. Nevertheless, an important difference between these diseases relies on the fact that atherosclerosis develops from early ages where inflammation dominates the very beginning of the disease. This review highlights the inflammatory nature of atherosclerosis and the role the immune system plays in the process of atherogenesis. Although treatment of atherosclerosis has been for years based on lipid-lowering therapies reducing a series of risk factors, the degree of success has been only limited because cardiovascular complications related to the evolution of atherosclerotic lesions continue to appear in the population worldwide. In this sense, alternative treatments for atherosclerosis have come into play where both innate and adaptive immunity have been proposed to modulate atherosclerosis-associated inflammatory phenomena. When tested for their atheroprotective properties, several immunogens have been studied through passive and active immunization with good results and, therefore, the strategy through vaccination to control the disease has been made possible. Many experimental pre-clinical studies demonstrating proof of concept that vaccination using DNA and protein with an effective use of adjuvants and the optimal route of administration now provide a tangible new therapeutic approach that sets the stage for several of these vaccines to be tested in large, randomized, long-term clinical studies. A vaccine ready for human use will only be accomplished through the close association between academia, regulatory government organizations and private industry, allowing the reality of a simple and successful therapy to reduce atherosclerosis and its severe clinical complications.

Vaccination for atherosclerosis

Atherosclerosis is an inflammatory disease, and several antigens have been shown to activate the immune response and affect the development of atherogenesis. This suggests that modulation of the immune system could represent a useful approach to prevent and/or treat this disorder. A vaccination approach might be a useful, effective tool in the modern arsenal of cardiovascular therapy and could possibly be used on a large scale at a low cost. Several modalities of vaccines have been tested against lipoproteins, cholesterol, molecules involved in cholesterol metabolism, atherosclerosis-associated microorganisms, and other molecules (heat shock protein, CD99, vascular endothelial growth factor-receptor, interleukin-2), with promising results. Nevertheless, a deeper understanding of the role of immunization in atherosclerosis will be essential to the use of vaccines in clinical medicine.