Anti-sense oligonucleotide therapies for the treatment of hyperlipidaemia

Navigating Lipodystrophy: Insights from Laminopathies and Beyond

Recent research into laminopathic lipodystrophies-rare genetic disorders caused by mutations in the LMNA gene-has greatly expanded our knowledge of their complex pathology and metabolic implications. These disorders, including Hutchinson-Gilford progeria syndrome (HGPS), Mandibuloacral Dysplasia (MAD), and Familial Partial Lipodystrophy (FPLD), serve as crucial models for studying accelerated aging and metabolic dysfunction, enhancing our understanding of the cellular and molecular mechanisms involved. Research on laminopathies has highlighted how LMNA mutations disrupt adipose tissue function and metabolic regulation, leading to altered fat distribution and metabolic pathway dysfunctions. Such insights improve our understanding of the pathophysiological interactions between genetic anomalies and metabolic processes. This review merges current knowledge on the phenotypic classifications of these diseases and their associated metabolic complications, such as insulin resistance, hypertriglyceridemia, hepatic steatosis, and metabolic syndrome, all of which elevate the risk of cardiovascular disease, stroke, and diabetes. Additionally, a range of published therapeutic strategies, including gene editing, antisense oligonucleotides, and novel pharmacological interventions aimed at addressing defective adipocyte differentiation and lipid metabolism, will be explored. These therapies target the core dysfunctional lamin A protein, aiming to mitigate symptoms and provide a foundation for addressing similar metabolic and genetic disorders.

PCSK9 and Lipid Metabolism: Genetic Variants, Current Therapies, and Cardiovascular Outcomes

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a crucial role in the modulation of lipid metabolism as a critical negative regulator of hepatic low-density lipoprotein receptor (LDLR) levels and circulating low-density lipoprotein (LDL) clearance. Numerous gain-of-function (GOF) mutations in PCSK9 have been identified as causing familial hypercholesterolemia (FH) by reducing LDLR levels, and loss-of-function (LOF) mutations associated with a hypercholesterolemia phenotype protective against atherosclerosis. PCSK9 represents an example of successful translational research resulting in the identification of PCSK9 as a major drug target for a lipid-lowering therapy. To explore the genetic constitution of PCSK9 and its biologic role, in this review, we summarize the current evidence of clinically significant PCSK9 genetic variants involved in lipid metabolism as well as emphasize the importance of PCSK9 inhibition for the improvement of cardiovascular outcomes by conducting a meta-analysis of the available data on the incidence of cardiovascular disease events.

Role of ABCA1 in Cardiovascular Disease

Cholesterol homeostasis plays a significant role in cardiovascular disease. Previous studies have indicated that ATP-binding cassette transporter A1 (ABCA1) is one of the most important proteins that maintains cholesterol homeostasis. ABCA1 mediates nascent high-density lipoprotein biogenesis. Upon binding with apolipoprotein A-I, ABCA1 facilitates the efflux of excess intracellular cholesterol and phospholipids and controls the rate-limiting step of reverse cholesterol transport. In addition, ABCA1 interacts with the apolipoprotein receptor and suppresses inflammation through a series of signaling pathways. Thus, ABCA1 may prevent cardiovascular disease by inhibiting inflammation and maintaining lipid homeostasis. Several studies have indicated that post-transcriptional modifications play a critical role in the regulation of ABCA1 transportation and plasma membrane localization, which affects its biological function. Meanwhile, carriers of the loss-of-function ABCA1 gene are often accompanied by decreased expression of ABCA1 and an increased risk of cardiovascular diseases. We summarized the ABCA1 transcription regulation mechanism, mutations, post-translational modifications, and their roles in the development of dyslipidemia, atherosclerosis, ischemia/reperfusion, myocardial infarction, and coronary heart disease.

The promising novel therapies for familial hypercholesterolemia

Background

The incidence of premature atherosclerotic cardiovascular disease in familial hypercholesterolemia (FH) is high. In recent years, novel therapeutic modalities have shown significant lipid‐lowering ability. In this paper, we summarize the recent developments in novel therapies for FH via the treatment of different targets and discuss the characteristics of each targeted therapy. Based on the process of protein synthesis, we attempt to summarize the direct‐effect targets including protein, RNA, and DNA.

Methods

For this systematic review, relevant studies are assessed by searching in several databases including PubMed, Web of Science, Scopus, and Google Scholar. The publications of original researches are considered for screening.

Results

Most drugs are protein‐targeted such as molecule‐based and monoclonal antibodies, including statins, ezetimibe, alirocumab, evolocumab, and evinacumab. Both antisense oligonucleotide (ASO) and small interfering RNA (siRNA) approaches, such as mipomersen, vupanorsen, inclisiran, and ARO‐ANG3, are designed to reduce the number of mRNA transcripts and then degrade proteins. DNA‐targeted therapies such as adeno‐associated virus or CRISPR–Cas9 modification could be used to deliver or edit genes to address a genetic deficiency and improve the related phenotype.

Conclusion

While the therapies based on different targets including protein, RNA, and DNA are on different stages of development, the mechanisms of these novel therapies may provide new ideas for precision medicine.

Future Impact of mRNA Therapy on Cardiovascular Diseases

The silver lining of the recent pandemic was that it accelerated the emergence of messenger ribonucleic acid (mRNA) therapeutics. The great promise of mRNA therapeutics was highlighted by the speed at which the vaccines were created, tested, and proven to be relatively safe and highly effective. There are a wide variety of mRNA therapeutics now under development, and dozens of these are in clinical trials. These therapeutics are generating a major paradigm shift in medical therapy, including the treatment of cardiovascular disease. Most of the cardiovascular mRNA therapies are still in preclinical development, although a phase 2a trial of mRNA therapy for myocardial ischemia has been completed with promising results.¹ The application of mRNA therapies to cardiovascular diseases is virtually limitless, and ongoing work includes mRNA therapies for myocardial ischemia, heart failure, arrhythmias, hypercholesterolemia, and arterial occlusive diseases. In addition, mRNA may be used to enhance cell therapies. In the future, mRNA therapies for cardiovascular disease are destined to supplant some of our current biologics and pharmacotherapies and will be used to treat previously untreatable cardiovascular diseases. Furthermore, mRNA therapies can be personalized, and they can be rapidly generated in current Good Manufacturing Practice facilities with a modest footprint, facilitating the rise of hospital-based regional centers of RNA therapeutics.

Volanesorsen for treatment of familial chylomicronemia syndrome

INTRODUCTION

Familial chylomicronemia syndrome (FCS) is a rare subtype of severe hypertriglyceridemia that affects ~1 in 100, 000 to 1,000,000 individuals. The major risk to health is acute pancreatitis. FCS is defined by biallelic loss-of-function mutations in one of five canonical genes that encode proteins critical to lipolysis of large triglyceride-rich lipoprotein particles. Unlike the vast majority of patients with severe hypertriglyceridemia, FCS patients lack any lipolytic capacity and are thus resistant to standard medications.

AREAS COVERED

This review focuses on a mechanism that effectively reduces elevated triglyceride levels in FCS, namely interference of synthesis of apolipoprotein (apo) C-III. Volanesorsen is an antisense RNA drug administered subcutaneously that knocks down apo C-III, resulting in dramatic reductions in triglyceride levels both in FCS patients and in the wider population of subjects with severe hypertriglyceridemia.

EXPERT OPINION

Volanesorsen is a highly effective treatment to reduce elevated triglycerides in FCS patients, providing proof-of-concept of the validity of targeting apo C-III. However, off target effects of volanesorsen, including thrombocytopenia, may ultimately limit its use. Nonetheless, building on the knowledge derived from the volanesorsen experience, there is intensified interest in promising newer agents that also target apo C-III but have technical modifications that limit potential off target adverse effects.

RNA therapeutics for cardiovascular disease

PURPOSE OF REVIEW

The development of mRNA vaccines against coronavirus disease 2019 has brought worldwide attention to the transformative potential of RNA-based therapeutics. The latter is essentially biological software that can be rapidly designed and generated, with an extensive catalog of applications. This review aims to highlight the mechanisms of action by which RNA-based drugs can affect specific gene targets and how RNA drugs can be employed to treat cardiovascular disease, with the focus on the therapeutics being evaluated in clinical trials. The recent advances in nanotechnology aiding the translation of such therapies into the clinic are also discussed.

RECENT FINDINGS

There is a growing body of studies demonstrating utility of RNA for targeting previously 'undruggable' pathways involved in development and progression of cardiovascular disease. Some challenges in RNA delivery have been overcome thanks to nanotechnology. There are several RNA-based drugs to treat hypercholesterolemia and myocardial infarction which are currently in clinical trials.

SUMMARY

RNA therapeutics is a rapidly emerging field of biotherapeutics based upon a powerful and versatile platform with a nearly unlimited capacity to address unmet clinical needs. These therapeutics are destined to change the standard of care for many diseases, including cardiovascular disease.

Volanesorsen in the Treatment of Familial Chylomicronemia Syndrome or Hypertriglyceridaemia: Design, Development and Place in Therapy

Severe hypertriglyceridaemia is associated with pancreatitis and chronic pancreatitis-induced diabetes. Familial chylomicronaemia syndrome (FCS) is a rare autosomal recessive disorder of lipid metabolism characterised by high levels of triglycerides (TGs) due to failure of chylomicron clearance. It causes repeated episodes of severe abdominal pain, fatigue and attacks of acute pancreatitis. There are few current options for its long-term management. The only universal long-term therapy is restriction of total dietary fat intake to <10-15% of daily calories (15 to 20g per day). Many patients have been treated with fibrates and statins with a variable response, but many remain susceptible to pancreatitis. Other genetic syndromes associated with hypertriglyceridaemia include familial partial lipodystrophy (FPLD). Targeting apolipoprotein C3 (apoC3) offers the ability to increase clearance of chylomicrons and other triglyceride-rich lipoproteins. Volanesorsen is an antisense oligonucleotide (ASO) inhibitor of apoC3, which reduces TG levels by 70–80% which has been shown also to reduce rates of pancreatitis and improve well-being in FCS and reduce TGs and improve insulin resistance in FPLD. It is now undergoing licensing and payer reviews. Further developments of antisense technology including small interfering RNA therapy to apoC3 as well as other approaches to modulating triglycerides are in development for this rare disorder.

The history of proprotein convertase subtilisin kexin-9 inhibitors and their role in the treatment of cardiovascular disease

A consensus has formed based on epidemiological studies and clinical trials that intervention to reduce low density lipoprotein cholesterol (LDL-C) will reduce cardiovascular disease (CVD) events. This has progressively reduced the thresholds for intervention and targets for treatment. Whist statins are sufficient for many people in primary prevention, they only partially achieve the newer targets of secondary prevention for established CVD. Increasing use of statins has highlighted that 1–2% cannot tolerate these drugs. Other cholesterol-lowering drugs such as ezetimibe add to the benefits of statins but have limited efficacy. The discovery of activating mutations in proprotein convertase subtilisin kexin-9 (PCSK9) as a cause of familial hypercholesterolaemia while inactivating mutations lower LDL-C led to the idea to develop PCSK9 inhibitors as drugs. This article reviews the history of lipid-lowering therapies, the discovery of PCSK9 and the development of PCSK9 inhibitors. It reviews the key trials of the current antibody-based drugs and how these have influenced new guidelines. It also reviews the controversy caused by their cost and the increasing application of health economics to determine the optimum strategy for implementation of novel therapeutic pathways and surveys other options for targeting PCSK9 as well as other LDL-C lowering compounds in late development.

A new dawn for managing dyslipidemias: The era of rna-based therapies

The high occurrence of atherosclerotic cardiovascular disease (ASCVD) events is still a major public health issue. Although a major determinant of ASCVD event reduction is the absolute change of low-density lipoprotein-cholesterol (LDL-C), considerable residual risk remains and new therapeutic options are required, in particular, to address triglyceride-rich lipoproteins and lipoprotein(a) [Lp(a)]. In the era of Genome Wide Association Studies and Mendelian Randomization analyses aimed at increasing the understanding of the pathophysiology of ASCVD, RNA-based therapies may offer more effective treatment options. The advantage of oligonucleotide-based treatments is that drug candidates are targeted at highly specific regions of RNA that code for proteins that in turn regulate lipid and lipoprotein metabolism. For LDL-C lowering, the use of inclisiran - a silencing RNA that inhibits proprotein convertase subtilisin/kexin type 9 (PCSK9) synthesis - has the advantage that a single s.c. injection lowers LDL-C for up to 6 months. In familial hypercholesterolemia, the use of the antisense oligonucleotide (ASO) mipomersen, targeting apolipoprotein (apoB) to reduce LDL-C, has been a valuable therapeutic approach, despite unquestionable safety concerns. The availability of specific ASOs lowering Lp(a) levels will allow rigorous testing of the Lp(a) hypothesis; by dramatically reducing plasma triglyceride levels, Volanesorsen (APOC3) and angiopoietin-like 3 (ANGPTL3)-LRx will further clarify the causality of triglyceride-rich lipoproteins in ASCVD. The rapid progress to date heralds a new dawn in therapeutic lipidology, but outcome, safety and cost-effectiveness studies are required to establish the role of these new agents in clinical practice.

An update on trials of novel lipid-lowering drugs

PURPOSE OF REVIEW

A number of novel trials have assessed the efficacy of new lipid-lowering therapies in cardiovascular disease (CVD).

RECENT FINDINGS

Proprotein convertase subtilisin kexin-9 inhibitors reduce low-density lipoprotein cholesterol (LDL-C) by 50-55%. A CVD outcome trial in patients with acute coronary syndromes with evolocumab achieved a LDL-C of 0.8 mmol/l (31 mg/dl) and a 20% relative risk reduction in CVD events in 2.2 years. Cholesterol ester transfer protein inhibitors raise high-density lipoprotein cholesterol and can lower LDL-C. Anacetrapib reduced coronary artery disease events by 7%, but not wider composite CVD outcomes, in a population with chronic CVD with pretreatment LDL-C of 1.6 mmol/l (62 mg/dl). The conflicting outcomes of cholesterol ester transfer protein inhibitor trials means these compounds are not being developed further. Trials using lipid drugs targeting inflammation have previously been generally unsuccessful, but recent data on the interleukin-1B receptor antagonist canakinumab has proven the concept of intervention on inflammation in atherosclerosis by showing a reduction in acute coronary interventions, but at the predictable cost of increased infections.

SUMMARY

Despite the success of proprotein convertase subtilisin kexin-9 inhibition, the ability to achieve low LDL-C with off-patent medications and the costs of novel therapies will limit their use even in high-risk patients and confine them to the highest-risk sub-groups of patients.

Antisense Oligonucleotides Targeting Lipoprotein(a)

PURPOSE OF REVIEW

High lipoprotein(a) levels are observationally and causally, from human genetics, associated with increased risk of cardiovascular disease including myocardial infarction and aortic valve stenosis. The European Atherosclerosis Society recommends screening for elevated lipoprotein(a) levels in high-risk patients. Different therapies have been suggested and some are used to treat elevated lipoprotein(a) levels such as niacin, PCSK9 inhibitors, and CETP inhibitors; however, to date, no randomized controlled trial has demonstrated that lowering of lipoprotein(a) leads to lower risk of cardiovascular disease.

RECENT FINDINGS

Synthetic oligonucleotides can be used to inactivate genes involved in disease processes. To lower lipoprotein(a), two antisense oligonucleotides have been developed, one targeting apolipoprotein B and one targeting apolipoprotein(a). Mipomersen is an antisense oligonucleotide targeting apolipoprotein B and thereby reducing levels of all apolipoprotein B containing lipoproteins in the circulation. Mipomersen has been shown to lower lipoprotein(a) by 20-50% in phase 3 studies. AKCEA-APO(a)-L_Rx is the most recent antisense oligonucleotide targeting apolipoprotein(a) and thereby uniquely targeting lipoprotein(a). It has been tested in a phase 2 study and has shown to lower lipoprotein(a) levels by 50-80%. The treatment of elevated lipoprotein(a) levels with the newest antisense oligonucleotides seems promising; however, no improvement in cardiovascular disease risk has yet been shown. However, a phase 3 study of AKCEA-APO(a)-L_Rx is being planned with cardiovascular disease as outcome, and results are awaited with great anticipation.

Non-antibody Approaches to Proprotein Convertase Subtilisin Kexin 9 Inhibition: siRNA, Antisense Oligonucleotides, Adnectins, Vaccination, and New Attempts at Small-Molecule Inhibitors Based on New Discoveries

Low-density lipoprotein (LDL) is one of the principal risk factors for atherosclerosis. Circulating LDL particles can penetrate into the sub-endothelial space of arterial walls. These particles undergo oxidation and promote an inflammatory response, resulting in injury to the vascular endothelial wall. Persistent elevation of LDL-cholesterol (LDL-C) is linked to the progression of fatty streaks to lipid-rich plaque and thus atherosclerosis. LDL-C is a causal factor for atherosclerotic cardiovascular disease and lowering it is beneficial across a range of conditions associated with high risk of cardiovascular events. Therefore, all guidelines-recommended initiations of statin therapy for patients at high cardiovascular risk is irrespective of LDL-C. In addition, intensive LDL-C lowering therapy with statins has been demonstrated to result in a greater reduction of cardiovascular event risk in large clinical trials. However, many high-risk patients receiving statins fail to achieve the guideline-recommended reduction in LDL-C levels in routine clinical practice. Moreover, low levels of adherence and often high rates of discontinuation demand the need for further therapies. Ezetimibe has typically been used as a complement to statins when further LDL-C reduction is required. More recently, proprotein convertase subtilisin kexin 9 (PCSK9) has emerged as a novel therapeutic target for lowering LDL-C levels, with PCSK9 inhibitors offering greater reductions than feasible through the addition of ezetimibe. PCSK9 monoclonal antibodies have been shown to not only considerably lower LDL-C levels but also cardiovascular events. However, PCSK9 monoclonal antibodies require once- or twice-monthly subcutaneous injections. Further, their manufacturing process is expensive, increasing the cost of therapy. Therefore, several non-antibody treatments to inhibit PCSK9 function are being developed as alternative approaches to monoclonal antibodies. These include gene-silencing or editing technologies, such as antisense oligonucleotides, small interfering RNA, and the clustered regularly interspaced short palindromic repeats/Cas9 platform; small-molecule inhibitors; mimetic peptides; adnectins; and vaccination. In this review, we summarize the current knowledge base on the role of PCSK9 in lipid metabolism and an overview of non-antibody approaches for PCSK9 inhibition and their limitations. The subsequent development of alternative approaches to PCSK9 inhibition may give us more affordable and convenient therapeutic options for the management of high-risk patients.

A systematic review of the epidemiology, pathophysiology and current management of hyperlipidaemic pancreatitis

BACKGROUND & AIMS

The aims of this systematic review were to define the epidemiology and pathophysiology of hyperlipidaemic pancreatitis, establish its association with clinical outcome and define management strategies.

METHODS

The Cochrane, Embase and Medline databases were searched, limited to the last decade, for articles on hyperlipidaemic pancreatitis. All randomised controlled trials, observational studies and case series (with a minimum of 10 patients) on hyperlipidaemic pancreatitis were included.

RESULTS

Thirty-eight studies with 1979 patients were included. The median admission triglyceride concentration was 42.8 mmol/L (range 13.6-108.6 mmol/L) [3785 mg/dL (range 1205-9612 mg/dL)]. Severe hypertriglyceridaemia (>1000 mg/dL, 11.0 mmol/L) was present in 1.7% of the adult population, and about 15-20% of these developed hyperlipidaemic acute pancreatitis. Medical management of severe hyperlipidaemia at onset of acute pancreatitis has not been investigated fully. However, tight regulation of triglyceride concentration after presentation with acute pancreatitis was found to reduce the risk of recurrence. Plasmapheresis reduced concentrations of triglycerides by up to 85%, but this did not impact morbidity or mortality. All studies included defined hyperlipidaemia as a more severe form of pancreatitis.

CONCLUSION

The available evidence suggests an increasing risk of acute pancreatitis in patients with hyperlipidaemia and a more severe form of pancreatitis. There is some evidence to suggest biochemical benefit of using novel techniques like plasmapheresis without the desired physiological benefit. However, there is a need for an international consensus on the management of hyperlipidaemic pancreatitis. More rigorous and methodologically robust studies are required to inform such consensus guidelines.

Methods of the Synthesis of Silicon-Containing Nanoparticles Intended for Nucleic Acid Delivery

A promising new approach to the treatment of viral infections and genetic diseases associated with damaged or foreign nucleic acids in the body is gene therapy, i.e., the use of antisense oligonucleotides, ribozymes, deoxyribozymes, siRNA, plasmid DNA, etc. (therapeutic nucleic acids). Selective recognition of target nucleic acids by these compounds based on highly specific complementary interaction can minimize negative side effects, which occur with currently used low molecular weight drugs. To apply a new generation of therapeutic agents in medical practice, it is necessary to solve the problem of their delivery into cells. Silicon-containing nanoparticles are considered as promising carriers for this purpose due to their biocompatibility, low toxicity, ability to biodegradation and excretion from the body, as well as the simplicity of the synthesis and modification. Silicon-containing nanoparticles are divided into two broad categories: solid (nonporous) and mesoporous silicon nanoparticles (MSN). This review gives a brief overview of the creation of mesoporous, multilayer, and other silicon-based nanoparticles. The publications concerning solid silicon-organic nanoparticles capable of binding and delivering nucleic acids into cells are discussed in more detail with emphasis on methods for their synthesis. The review covers publications over the past 15 years, which describe the classical Stöber method, the microemulsion method, modification of commercial silica nanoparticles, and other strategies.

Further options for treating lipids in people with diabetes: targeting LDL-cholesterol and beyond

Diabetes is associated with increased cardiovascular disease (CVD) risk. Previous studies with statins have established that a 1 mmol/l reduction in LDL-cholesterol reduces CVD events by 21% over 5 years in people with diabetes. More recently, trials in people with acute coronary syndromes showed that ezetimibe reduced CVD events by 6% at 5 years and achieved a LDL-cholesterol of 1.6 mmol/l with better results in people with Type 2 diabetes. Several novel lipid-lowering therapies have recently been developed. Most data have been accumulated with proprotein convertase subtilisin kexin-9 (PCSK-9) inhibitors, which reduce LDL-cholesterol by 50-55%. A large CVD outcome trial with evolocumab, in which 40% of participants had diabetes, achieved a LDL-cholesterol of 0.8 mmol/l and showed a consistent 20% relative risk reduction within 2 years, including in people with diabetes. Trials to increase HDL-cholesterol using cholesterol ester transfer protein (CETP) inhibitors have generally underwhelmed. Although anacetrapib reduced coronary ischaemic events by 7% in a population with chronic CVD, more expansive CVD endpoints were not improved. The complex nature of CETP inhibitor trial outcomes means that these compounds are not being developed further. Trials targeting inflammation-associated lipids have been generally unsuccessful but recent data on the interleukin-1B receptor antagonist canakinumab have shown a reduction in acute coronary intervention, validating this target although at the cost of increased infections. The ability to achieve low LDL-cholesterol with off-patent medications and the costs of novel therapies will confine the use of novel agents to subgroups of people at highest risk of CVD.

Enhanced Hepatic PPARα Activity Links GLUT8 Deficiency to Augmented Peripheral Fasting Responses in Male Mice

The adaptive fasting response is invoked as a promising cardiometabolic and neurodegenerative therapeutic pathway. We and others have defined the carbohydrate transporter glucose transporter 8 (GLUT8) as a critical regulator of hepatic and whole-organism metabolic homeostasis in the overfed and diabetic states. However, the functions of this critical transporter in the physiological fasting response remain poorly understood. Here, we tested the hypothesis that GLUT8 modulates the adaptive hepatic fasting response. We demonstrate that mice with targeted Slc2a8 disruption exhibit enhanced thermogenesis, ketogenesis, and peripheral lipid mobilization during fasting. These metabolic enhancements were observed in the context of mildly impaired hepatic mitochondrial oxidative metabolism in vivo and in vitro. Mechanistically, we show that hepatic peroxisome proliferator-activated receptor α (PPARα) and its transcriptional fasting response target hepatokine, fibroblast growth factor (FGF)21, are cell-autonomously hyperactivated in GLUT8-deficient liver and in isolated primary murine hepatocytes during nutrient depletion. Hepatic PPARα knockdown in GLUT8-deficient mice normalized the enhanced ketogenic and FGF21 secretory responses and decreased mitochondrial respiratory function without altering the hyperthermic response to fasting. Our data demonstrate that hepatocyte GLUT8 regulates adaptive fasting in part through regulation of the PPARα signaling cascade. Moreover, the ketotic and thermic responses to fasting are differentially encoded within the GLUT8-PPARα communication axis. GLUT8 therefore represents a therapeutic target that can be leveraged against cardiometabolic disease.

Advances in lipid-lowering therapy through gene-silencing technologies

New treatment opportunities are emerging in the field of lipid-lowering therapy through gene-silencing approaches. Both antisense oligonucleotide inhibition and small interfering RNA technology aim to degrade gene mRNA transcripts to reduce protein production and plasma lipoprotein levels. Elevated levels of LDL, remnant lipoproteins, and lipoprotein(a) all cause cardiovascular disease, whereas elevated levels of triglyceride-rich lipoproteins in some patients can cause acute pancreatitis. The levels of each of these lipoproteins can be reduced using gene-silencing therapies by targeting proteins that have an important role in lipoprotein production or removal (for example, the protein products of ANGPTL3, APOB, APOC3, LPA, and PCSK9). Using this technology, plasma levels of these lipoproteins can be reduced by 50-90% with 2-12 injections per year; such dramatic reductions are likely to reduce the incidence of cardiovascular disease or acute pancreatitis in at-risk patients. The reported adverse effects of these new therapies include injection-site reactions, flu-like symptoms, and low blood platelet counts. However, newer-generation drugs are more efficiently delivered to liver cells, requiring lower drug doses, which leads to fewer adverse effects. Although these findings are promising, robust evidence of cardiovascular disease reduction and long-term safety is needed before these gene-silencing technologies can have widespread implementation. Before the availability of such evidence, these drugs might have roles in patients with unmet medical needs through orphan indications.

Triglyceride-lowering trials

PURPOSE OF REVIEW

We provide an overview of current evidence about the independent role of high triglyceride levels for cardiovascular risk and for acute pancreatitis.

RECENT FINDINGS

Natural experiments of Mendelian randomization have given us a deeper understanding about the molecular pathways involved in triglyceride metabolism. Individuals with low-triglyceride levels generally have lower rates of cardiovascular disease (CVD). There has been a significant growth in the development of new agents that modulate enzymes involved in a variety of aspects of triglyceride packaging into VLDL or chylomicron particles, and triglyceride catabolism. Antisense inhibitors of apolipoprotein CIII are being tested, as are a variety of agents designed to increase lipoprotein lipase activity. Large-scale trials are underway with purified fatty acid (FA) formulations in over 20 000 individuals in aggregate. A large study of a new fibrate is underway.

SUMMARY

A focus on patients with elevated triglyceride levels is a new paradigm not previously the focus of large trials. Clinical outcome data on cardiovascular risk reductions remains sparse. Some drugs are already approved for use in rare inherited disorders predisposing to severe hypertriglyceridaemia and acute pancreatitis. Safety and costs issues are critical.

Translational applications of microRNAs in cancer, and therapeutic implications

The search for targeted novel therapies for cancer is ongoing. MicroRNAs (miRNAs) display a number of characteristics making them an attractive and realisable option. In this review, we explore these applications, ranging from diagnostics, prognostics, disease surveillance, to being a primary therapy or a tool to sensitise patients to treatment modalities such as chemotherapy and radiotherapy. We take a particular perspective towards miRNAs and their impact on rare cancers. Advancement in the delivery of miRNAs, from viral vectors and liposomal delivery to nanoparticle based, has led to a number of pre-clinical and clinical applications for microRNA cancer therapeutics. This is promising, especially in the setting of rare cancers.

Mesoporous Silica Nanoparticles as Carriers for Intracellular Delivery of Nucleic Acids and Subsequent Therapeutic Applications

Nucleic acids, including DNA, microRNA (miRNA), small interfering RNA (siRNA), and antisense oligonucleotide (ASO), are powerful gene regulators, which have been demonstrated as promising drug candidates for therapeutic treatments. Nevertheless, poor cellular membrane permeability and serum stability have greatly hindered the applications of nucleic acids in biomedicine. To address these issues, associate carriers that can encapsulate and protect nucleic acids are urgently required. Mesoporous silica nanoparticles (MSNs or MSNPs), which are nanomaterials with excellent biocompatibility, large surface area for functionalization, and tunable pore size for encapsulating different cargos, are emerging as novel and ideal biomaterials for different biomedical applications. In this review paper, we focus on the applications of MSNs in nucleic acid delivery and nucleic acid-guided therapeutic treatments. General strategies for the preparation of nucleic acid-MSN complexes will be firstly introduced, followed by a summary of recent applications of MSNs in nucleic acid delivery and nucleic acid-guided therapeutics.

Hypertriglyceridaemia and risk of coronary artery disease

An elevated serum level of LDL cholesterol is a well-known risk factor for cardiovascular disease (CVD), but the role of elevated triglyceride levels is debated. Controversies regarding hypertriglyceridaemia as an independent risk factor for CVD have occurred partly because elevated triglyceride levels are often a component of atherogenic dyslipidaemia - they are associated with decreased levels of HDL cholesterol and increased levels of small dense LDL particles, which are highly atherogenic. Findings from several large studies indicate that elevated levels of triglycerides (either fasting or nonfasting) or, more specifically, triglyceride-rich lipoproteins and their remnants, are independently associated with increased risk of CVD. Possible mechanisms for this association include excessive free fatty acid release, production of proinflammatory cytokines, coagulation factors, and impairment of fibrinolysis. Therapeutic targeting of hypertriglyceridaemia could, therefore, reduce CVD and cardiovascular events, beyond the reduction achieved by LDL-cholesterol lowering. Elevated triglyceride levels are reduced with lifestyle interventions and fibrates, which can be combined with omega-3 fatty acids. Some new drugs are on the horizon, such as volanesorsen (which targets apolipoprotein C-III), pemafibrate, and others. However, CVD outcome studies with triglyceride-lowering agents have produced inconsistent results, meaning that no convincing evidence is available that lowering triglycerides by any approach can reduce mortality.