Gene therapy to treat cardiovascular disease

Cardiac gene delivery using ultrasound: State of the field

Over the past two decades, there has been tremendous and exciting progress toward extending the use of medical ultrasound beyond a traditional imaging tool. Ultrasound contrast agents, typically used for improved visualization of blood flow, have been explored as novel non-viral gene delivery vectors for cardiovascular therapy. Given this adaptation to ultrasound contrast-enhancing agents, this presents as an image-guided and site-specific gene delivery technique with potential for multi-gene and repeatable delivery protocols-overcoming some of the limitations of alternative gene therapy approaches. In this review, we provide an overview of the studies to date that employ this technique toward cardiac gene therapy using cardiovascular disease animal models and summarize their key findings.

Cell-Specific mRNA Therapeutics for Cardiovascular Diseases and Regeneration

Cardiovascular diseases (CVDs) represent a significant global health burden, demanding innovative therapeutic approaches. In recent years, mRNA therapeutics have emerged as a promising strategy to combat CVDs effectively. Unlike conventional small-molecule drugs, mRNA therapeutics enable the direct modulation of cellular functions by delivering specific mRNA molecules to target cells. This approach offers unprecedented advantages, including the ability to harness endogenous cellular machinery for protein synthesis, thus allowing precise control over gene expression without insertion into the genome. This review summarizes the current status of the potential of cell-specific mRNA therapeutics in the context of cardiovascular diseases. First, it outlines the challenges associated with traditional CVD treatments and emphasizes the need for targeted therapies. Subsequently, it elucidates the underlying principles of mRNA therapeutics and the development of advanced delivery systems to ensure cell-specificity and enhanced efficacy. Notably, innovative delivery methods such as lipid nanoparticles and exosomes have shown promise in improving the targeted delivery of mRNA to cardiac cells, activated fibroblasts, and other relevant cell types. Furthermore, the review highlights the diverse applications of cell-specific mRNA therapeutics in addressing various aspects of cardiovascular diseases, including atherosclerosis, myocardial infarction, heart failure, and arrhythmias. By modulating key regulatory genes involved in cardiomyocyte proliferation, inflammation, angiogenesis, tissue repair, and cell survival, mRNA therapeutics hold the potential to intervene at multiple stages of CVD pathogenesis. Despite its immense potential, this abstract acknowledges the challenges in translating cell-specific mRNA therapeutics from preclinical studies to clinical applications like off-target effects and delivery. In conclusion, cell-specific mRNA therapeutics have emerged as a revolutionary gene therapy approach for CVD, offering targeted interventions with the potential to significantly improve patient outcomes.

Current Landscape of Gene Therapy for the Treatment of Cardiovascular Disorders

Cardiovascular disorders (CVD) are the primary cause of death worldwide. Multiple factors have been accepted to cause cardiovascular diseases; among them, smoking, physical inactivity, unhealthy eating habits, age, and family history are flag-bearers. Individuals at risk of developing CVD are suggested to make drastic habitual changes as the primary intervention to prevent CVD; however, over time, the disease is bound to worsen. This is when secondary interventions come into play, including antihypertensive, anti-lipidemic, anti-anginal, and inotropic drugs. These drugs usually undergo surgical intervention in patients with a much higher risk of heart failure. These therapeutic agents increase the survival rate, decrease the severity of symptoms and the discomfort that comes with them, and increase the overall quality of life. However, most individuals succumb to this disease. None of these treatments address the molecular mechanism of the disease and hence are unable to halt the pathological worsening of the disease. Gene therapy offers a more efficient, potent, and important novel approach to counter the disease, as it has the potential to permanently eradicate the disease from the patients and even in the upcoming generations. However, this therapy is associated with significant risks and ethical considerations that pose noteworthy resistance. In this review, we discuss various methods of gene therapy for cardiovascular disorders and address the ethical conundrum surrounding it.

Modern medical services, a double-edged sword manages symptoms, but accumulates genetic background of cardiovascular diseases: A cross populational analysis of 217 countries

Background and Aims

Through reduced natural selection, measured with Biological State Index (I bs), modern medicine enables most people to survive well beyond the reproductive lifespan leading to deleterious gene accumulation in population. This study explored the role of reduced natural selection in increasing cardiovascular disease (CVD) incidence worldwide.

Methods

Country-specific estimates of CVD incidence and the index of reduced natural selection were captured for analysis of their correlation. Aging, affluence, obesity prevalence, and urbanization were considered as the potential confounders in the analyses.

Results

Worldwide, I bs was significantly correlated with CVD incidence in the bivariate correlation analyses. This relationship remains when the contributing effects from aging, affluence, obesity prevalence, and urbanization are removed in partial correlation model. Multiple linear regression (enter) shows that I bs is a significant predictor of CVD incidence. Stepwise multiple linear regression selects I bs as the variable having the second greatest influence on CVD incidence after ageing. I bs showed a significantly greater correlation with CVD incidence in low- and middle-income countries (LMICs) than in high-income countries.

Conclusion

Worldwide, through reducing natural selection, the side effects of healthcare services may have been partially contributing to the increase of CVD incidence worldwide with special regard to LMICs.

Three-dimensional heart extracellular matrix enhances chemically induced direct cardiac reprogramming

Direct cardiac reprogramming has emerged as a promising therapeutic approach for cardiac regeneration. Full chemical reprogramming with small molecules to generate cardiomyocytes may be more amenable than genetic reprogramming for clinical applications as it avoids safety concerns associated with genetic manipulations. However, challenges remain regarding low conversion efficiency and incomplete cardiomyocyte maturation. Furthermore, the therapeutic potential of chemically induced cardiomyocytes (CiCMs) has not been investigated. Here, we report that a three-dimensional microenvironment reconstituted with decellularized heart extracellular matrix can enhance chemical reprogramming and cardiac maturation of fibroblasts to cardiomyocytes. The resultant CiCMs exhibit elevated cardiac marker expression, sarcomeric organization, and improved electrophysiological features and drug responses. We investigated the therapeutic potential of CiCMs reprogrammed in three-dimensional heart extracellular matrix in a rat model of myocardial infarction. Our platform can facilitate the use of CiCMs for regenerative medicine, disease modeling, and drug screening.

Deciphering the Basis of Molecular Biology of Selected Cardiovascular Diseases: A View on Network Medicine

Cardiovascular diseases are the leading cause of death across the world. For decades, researchers have been studying the causes of cardiovascular disease, yet many of them remain undiscovered or poorly understood. Network medicine is a recently expanding, integrative field that attempts to elucidate this issue by conceiving of disease as the result of disruptive links between multiple interconnected biological components. Still in its nascent stages, this revolutionary application of network science facilitated a number of important discoveries in complex disease mechanisms. As methodologies become more advanced, network medicine harbors the potential to expound on the molecular and genetic complexities of disease to differentiate how these intricacies govern disease manifestations, prognosis, and therapy. This is of paramount importance for confronting the incredible challenges of current and future cardiovascular disease research. In this review, we summarize the principal molecular and genetic mechanisms of common cardiac pathophysiologies as well as discuss the existing knowledge on therapeutic strategies to prevent, halt, or reverse these pathologies.

Crosstalk between Ca2+ Signaling and Cancer Stemness: The Link to Cisplatin Resistance

In the fight against cancer, therapeutic strategies using cisplatin are severely limited by the appearance of a resistant phenotype. While cisplatin is usually efficient at the beginning of the treatment, several patients endure resistance to this agent and face relapse. One of the reasons for this resistant phenotype is the emergence of a cell subpopulation known as cancer stem cells (CSCs). Due to their quiescent phenotype and self-renewal abilities, these cells have recently been recognized as a crucial field of investigation in cancer and treatment resistance. Changes in intracellular calcium (Ca²⁺) through Ca²⁺ channel activity are essential for many cellular processes such as proliferation, migration, differentiation, and survival in various cell types. It is now proved that altered Ca²⁺ signaling is a hallmark of cancer, and several Ca²⁺ channels have been linked to CSC functions and therapy resistance. Moreover, cisplatin was shown to interfere with Ca²⁺ homeostasis; thus, it is considered likely that cisplatin-induced aberrant Ca²⁺ signaling is linked to CSCs biology and, therefore, therapy failure. The molecular signature defining the resistant phenotype varies between tumors, and the number of resistance mechanisms activated in response to a range of pressures dictates the global degree of cisplatin resistance. However, if we can understand the molecular mechanisms linking Ca²⁺ to cisplatin-induced resistance and CSC behaviors, alternative and novel therapeutic strategies could be considered. In this review, we examine how cisplatin interferes with Ca²⁺ homeostasis in tumor cells. We also summarize how cisplatin induces CSC markers in cancer. Finally, we highlight the role of Ca²⁺ in cancer stemness and focus on how they are involved in cisplatin-induced resistance through the increase of cancer stem cell populations and via specific pathways.

Gallic acid-mitochondria targeting sequence-H3R9 induces mitochondria-targeted cytoprotection

The development of selective targeting of drug molecules towards the mitochondria is an important issue related to therapy efficacy. In this study, we report that gallic acid (GA)-mitochondria targeting sequence (MTS)-H₃R₉ exhibits a dual role as a mitochondria-targeting vehicle with antioxidant activity for disease therapy. In viability assays, GA-MTS-H₃R₉ showed a better rescue action compared to that of MTS-H₃R₉. GA-MTS-H₃R₉ dramatically exhibited cell penetration and intercellular uptake compared to MTS and fit escape from lysosome release to the cytosol. We demonstrated the useful targeting of GA-MTS-H₃R₉ towards mitochondria in AC16 cells. Also, we observed that the antioxidant properties of mitochondrial-accrued GA-MTS-H₃R₉ alleviated cell damage by reactive oxygen species production and disrupted mitochondrial membrane potential. GA-MTS-H₃R₉ showed a very increased cytoprotective effect against anticancer activity compared to that of MTS-H₃R₉. We showed that GA-MTS-H₃R₉ can act as a vehicle for mitochondria-targeting and as a reagent for therapeutic applications intended for cardiovascular disease treatment.

The adiponectin signalling pathway - A therapeutic target for the cardiac complications of type 2 diabetes?

Diabetes is associated with an increased risk of heart failure (HF). This is commonly termed diabetic cardiomyopathy and is often characterised by increased cardiac fibrosis, pathological hypertrophy, increased oxidative and endoplasmic reticulum stress as well as diastolic dysfunction. Adiponectin is a cardioprotective adipokine that is downregulated in settings of type 2 diabetes (T2D) and obesity. Furthermore, both adiponectin receptors (AdipoR1 and R2) are also downregulated in these settings which further results in impaired cardiac adiponectin signalling and reduced cardioprotection. In many cardiac pathologies, adiponectin signalling has been shown to protect against cardiac remodelling and lipotoxicity, however its cardioprotective actions in T2D-induced cardiomyopathy remain unresolved. Diabetic cardiomyopathy has historically lacked effective treatment options. In this review, we summarise the current evidence for links between the suppressed adiponectin signalling pathway and cardiac dysfunction, in diabetes. We describe adiponectin receptor-mediated signalling pathways that are normally associated with cardioprotection, as well as current and potential future therapeutic approaches that could target this pathway as possible interventions for diabetic cardiomyopathy.

Metal-based nanoparticles: Promising tools for the management of cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide. A search for more effective treatments of CVD is increasingly needed. Major advances in nanotechnology opened new avenues in CVD therapeutics. Owing to their special properties, iron oxide, gold and silver nanoparticles (NPs) could exert various effects in the management and treatment of CVD. The role of iron oxide NPs in the detection and identification of atherosclerotic plaques is receiving increased attention. Moreover, these NPs enhance targeted stem cell delivery, thereby potentiating the regenerative capacity at the injured sites. In addition to their antioxidative and antihypertrophic capacities, gold NPs have also been shown to be useful in the identification of plaques and recognition of inflammatory markers. Contrary to first reports suggestive of their cardio-vasculoprotective role, silver NPs now appear to exert negative effects on the cardiovascular system. Indeed, these NPs appear to negatively modulate inflammation and cholesterol uptake, both of which exacerbate atherosclerosis. Moreover, silver NPs may precipitate bradycardia, conduction block and sudden cardiac death. In this review, we dissect the cellular responses and toxicity profiles of these NPs from various perspectives including cellular and molecular ones.

Bioengineering Technologies for Cardiac Regenerative Medicine

Cardiac regenerative medicine faces big challenges such as a lack of adult cardiac stem cells, low turnover of mature cardiomyocytes, and difficulty in therapeutic delivery to the injured heart. The interaction of bioengineering and cardiac regenerative medicine offers innovative solutions to this field. For example, cell reprogramming technology has been applied by both direct and indirect routes to generate patient-specific cardiomyocytes. Various viral and non-viral vectors have been utilized for gene editing to intervene gene expression patterns during the cardiac remodeling process. Cell-derived protein factors, exosomes, and miRNAs have been isolated and delivered through engineered particles to overcome many innate limitations of live cell therapy. Protein decoration, antibody modification, and platelet membranes have been used for targeting and precision medicine. Cardiac patches have been used for transferring therapeutics with better retention and integration. Other technologies such as 3D printing and 3D culture have been used to create replaceable cardiac tissue. In this review, we discuss recent advancements in bioengineering and biotechnologies for cardiac regenerative medicine.

Nanotechnology applications for cardiovascular disease treatment: Current and future perspectives

A large majority of cardiovascular nanomedicine research has focused on fabricating designer nanoparticles for improved targeting as a means to overcome biological barriers. For cardiac related disorders, such as atherosclerosis, hypertension, and myocardial infarction, designer micro or nanoparticles are often administered into the vasculature or targeted vessel with the hope to circumvent problems associated with conventional drug delivery, including negative systemic side effects. Additionally, novel nano-drug carriers that enter circulation can be selectively uptaken by immune cells with the intended purpose that they modulate inflammatory processes and migrate locally to plaque for therapeutic payload delivery. Indeed, innovative design in nanoparticle composition, formulation, and functionalization has advanced the field as a means to achieve therapeutic efficacy for a variety of cardiac disease indications. This perspective aims to discuss these advances and provide new interpretations of how nanotechnology can be best applied to aid in cardiovascular disease treatment. In an effort to spark discussions on where the field of research should go, we share our outlook in new areas of nanotechnological inclusion and integration, such as in vascular, implantable, or wearable device technologies as well as nanocomposites and nanocoatings. Further, as cardiovascular diseases (CVD) increasingly claim a number of lives globally, we propose more attention should be placed by researchers on nanotechnological approaches for risk factor treatment to aid in early prevention and treatment of CVD.

Characterisation of the developing heart in a pressure overloaded model utilising RNA sequencing to direct functional analysis

Cardiogenesis is influenced by both environmental and genetic factors, with blood flow playing a critical role in cardiac remodelling. Perturbation of any of these factors could lead to abnormal heart development and hence the formation of congenital heart defects. Although abnormal blood flow has been associated with a number of heart defects, the effects of abnormal pressure load on the developing heart gene expression profile have to date not clearly been defined. To determine the heart transcriptional response to haemodynamic alteration during development, outflow tract (OFT) banding was employed in the chick embryo at Hamburger and Hamilton stage (HH) 21. Stereological and expression studies, including the use of global expression analysis by RNA sequencing with an optimised procedure for effective globin depletion, were subsequently performed on HH29 OFT-banded hearts and compared with sham control hearts, with further targeted expression investigations at HH35. The OFT-banded hearts were found to have an abnormal morphology with a rounded appearance and left-sided dilation in comparison with controls. Internal analysis showed they typically had a ventricular septal defect and reductions in the myocardial wall and trabeculae, with an increase in the lumen on the left side of the heart. There was also a significant reduction in apoptosis. The differentially expressed genes were found to be predominately involved in contraction, metabolism, apoptosis and neural development, suggesting a cardioprotective mechanism had been induced. Therefore, altered haemodynamics during development leads to left-sided dilation and differential expression of genes that may be associated with stress and maintaining cardiac output.

Non-viral vector based gene transfection with human induced pluripotent stem cells derived cardiomyocytes

Non-viral transfection of mammalian cardiomyocytes (CMs) is challenging. The current study aims to characterize and determine the non-viral vector based gene transfection efficiency with human induced pluripotent stem cells (hiPSCs) derived cardiomyocytes (hiPSC-CMs). hiPSC-CMs differentiated from PCBC hiPSCs were used as a cell model to be transfected with plasmids carrying green fluorescence protein (pGFP) using polyethylenimine (PEI), including Transporter 5 Transfection Reagent (TR5) and PEI25, and liposome, including lipofectamine-2000 (Lipo2K), lipofectamine-3000 (Lipo3K), and Lipofectamine STEM (LipoSTEM). The gene transfection efficiency and cell viability were quantified by flow cytometry. We found that the highest gene transfection efficiency in hiPSC-CMs on day 14 of contraction can be achieved by LipoSTEM which was about 32.5 ± 6.7%. However, it also cuased poor cell viability (60.1 ± 4.5%). Furthermore, a prolonged culture of (transfection on day 23 of contraction) hiPSC-CMs not only improved gene transfection (54.5 ± 8.9%), but also enhanced cell viability (74 ± 4.9%) by LipoSTEM. Based on this optimized gene transfection condition, the highest gene transfection efficiency was 55.6 ± 7.8% or 34.1 ± 4%, respectively, for P1C1 or DP3 hiPSC line that was derived from healthy donor (P1C1) or patient with diabetes (DP3). The cell viability was 80.8 ± 5.2% or 92.9 ± 2.24%, respectively, for P1C1 or DP3. LipoSTEM is a better non-viral vector for gene transfection of hiPSC-CMs. The highest pGFP gene transfection efficiency can reach >50% for normal hiPSC-CMs or >30% for diabetic hiPSC-CMs.

Translational Models of Arrhythmia Mechanisms and Susceptibility: Success and Challenges of Modeling Human Disease

We discuss large animal translational models of arrhythmia susceptibility and sudden cardiac death, focusing on important considerations when interpreting the data derived before applying them to human trials. The utility of large animal models of arrhythmia and the pros and cons of specific translational large animals used will be discussed, including the necessary tradeoffs between models designed to derive mechanisms vs. those to test therapies. Recent technical advancements which can be applied to large animal models of arrhythmias to better elucidate mechanistic insights will be introduced. Finally, some specific examples of past successes and challenges in translating the results of large animal models of arrhythmias to clinical trials and practice will be examined, and common themes regarding the success and failure of translating studies to therapy in man will be discussed.

In Vivo Restoration of Myocardial Conduction With Carbon Nanotube Fibers

BACKGROUND

Impaired myocardial conduction is the underlying mechanism for re-entrant arrhythmias. Carbon nanotube fibers (CNTfs) combine the mechanical properties of suture materials with the conductive properties of metals and may form a restorative solution to impaired myocardial conduction.

METHODS

Acute open chest electrophysiology studies were performed in sheep (n=3). Radiofrequency ablation was used to create epicardial conduction delay after which CNTf and then silk suture controls were applied. CNTfs were surgically sewn across the right atrioventricular junction in rodents, and acute (n=3) and chronic (4-week, n=6) electrophysiology studies were performed. Rodent toxicity studies (n=10) were performed. Electrical analysis of the CNTf-myocardial interface was performed.

RESULTS

In all cases, the large animal studies demonstrated improvement in conduction velocity using CNTf. The acute rodent model demonstrated ventricular preexcitation during sinus rhythm. All chronic cases demonstrated resumption of atrioventricular conduction, but these required atrial pacing. There was no gross or histopathologic evidence of toxicity. Ex vivo studies demonstrated contact impedance significantly lower than platinum iridium.

CONCLUSIONS

Here, we show that in sheep, CNTfs sewn across epicardial scar acutely improve conduction. In addition, CNTf maintain conduction for 1 month after atrioventricular nodal ablation in the absence of inflammatory or toxic responses in rats but only in the paced condition. The CNTf/myocardial interface has such low impedance that CNTf can facilitate local, downstream myocardial activation. CNTf are conductive, biocompatible materials that restore electrical conduction in diseased myocardium, offering potential long-term restorative solutions in pathologies interrupting efficient electrical transduction in electrically excitable tissues.

Site-Specific Glycation and Chemo-enzymatic Antibody Sortagging for the Retargeting of rAAV6 to Inflamed Endothelium

Gene therapy holds great potential for conditions such as cardiovascular disease, including atherosclerosis and also vascular cancers, yet available vectors such as the adeno-associated virus (rAAV) transduce the vasculature poorly. To enable retargeting, a single-chain antibody (scFv) that binds to the vascular cell-adhesion molecule (VCAM-1) overexpressed at areas of endothelial inflammation was site specifically and covalently conjugated to the exterior of rAAV6. To achieve conjugation, the scFv was functionalized with an orthogonal click chemistry group. This conjugation utilized site-specific sortase A methodology, thus preserving scFv binding capacity to VCAM-1. The AAV6 was separately functionalized with 4-azidophenyl glyoxal (APGO) via covalent adducts to arginine residues in the capsid’s heparin co-receptor binding region. APGO functionalization removed native tropism, greatly reducing rAAV6-GFP transduction into all cells tested, and the effect was similar to the inhibition seen in the presence of heparin. Utilizing the incorporated functionalizations, the scFv was then covalently conjugated to the exterior of rAAV6 via strain-promoted azide-alkyne cycloaddition (SPAAC). With both the removal of native heparin tropism and the addition of VCAM-1 targeting, rAAV6 transduction of endothelial cells was greatly enhanced compared to control cells. Thus, this novel and modular targeting system could have further application in re-directing AAV6 toward inflamed endothelium for therapeutic use.

Evaluation and comparison of cytotoxicity, genotoxicity, and apoptotic effects of poly-l-lysine/plasmid DNA micro- and nanoparticles

The principal impediment to gene therapy is the development of efficient, nontoxic gene carriers that can handle and deliver foreign genetic materials into various cell types, including healthy and cancerous cells. Poly-l-lysine (PLL) polymers are one of the most favorable gene carriers among nonviral vectors, and PLL had low transfection and safety issues. The purpose of this study was to measure cellular toxicity, DNA damage, and apoptotic effects of PLL nanoparticles. Neuro2A mammalian cells were cultured and exposed to PLL/DNA complexes at different polymer/DNA ratios ( C/ P ratio 2 and 6) for 24 h. To evaluate metabolic activity, genotoxicity, and apoptotic influences of PLL nanoparticle, the following experimental methods were employed, in order: 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), DNA damage (COMET analysis) assay, and sub-G1 peak apoptosis assay. Our data indicate that toxicity is concentration dependent and a high concentration of polymer declined the metabolic activity. In addition, largest complexes ( C/ P 6 in HEPES buffered saline buffer) have slighter negative impact on metabolic activity. In agreement with our cytotoxicity data, apoptotic assay result represented that increase in size of PLL/DNA complexes decrease the number of apoptotic cells. Also, there was a remarkable increase in percent tail DNA of Neuro2A cells treated with higher concentration of PLL and its polyplexes. The present study demonstrated that PLL/DNA complexes caused cytotoxic, apoptotic, and genotoxic effects in a dose-dependent and weight ratio-dependent manner, which also affected the size of polyplexes.

Protease-Activatable Adeno-Associated Virus Vector for Gene Delivery to Damaged Heart Tissue

Adeno-associated virus (AAV) has emerged as a promising gene delivery vector because of its non-pathogenicity, simple structure and genome, and low immunogenicity compared to other viruses. However, its adoption as a safe and effective delivery vector for certain diseases relies on altering its tropism to deliver transgenes to desired cell populations. To this end, we have developed a protease-activatable AAV vector, named provector, that responds to elevated extracellular protease activity commonly found in diseased tissue microenvironments. The AAV9-based provector is initially inactive, but then it can be switched on by matrix metalloproteinases (MMP)-2 and -9. Cryo-electron microscopy and image reconstruction reveal that the provector capsid is structurally similar to that of AAV9, with a flexible peptide insertion at the top of the 3-fold protrusions. In an in vivo model of myocardial infarction (MI), the provector is able to deliver transgenes site specifically to high-MMP-activity regions of the damaged heart, with concomitant decreased delivery to many off-target organs, including the liver. The AAV provector may be useful in the future for enhanced delivery of transgenes to sites of cardiac damage.

Delivery of viral vectors for gene therapy in intimal hyperplasia and restenosis in atherosclerotic swine

Cardiovascular diseases including atherosclerosis are a major financial and health burden globally. Inflammation associated with atherosclerosis results in the development of plaques that can rupture causing thrombosis, stroke, or death. The most widely used treatment for the removal of atherosclerotic plaques is percutaneous transluminal coronary angioplasty (PTCA) with or without stenting. Although this is a safer and minimally invasive method, restenosis and intimal hyperplasia after interventional procedure remains a major hurdle and more refined approaches are needed. Studies in large animal models such as pigs have facilitated a greater understanding of the underlying mechanisms of the disease and provided novel targets for therapeutic intervention. In pre-clinical studies, viral vector gene therapy has emerged as a promising option for the reduction and/or prevention of restenosis and intimal hyperplasia. Although studies in animal models have generated promising results, clinical trials have yet to prove the clinical efficacy of gene therapy in coronary artery diseases. In this review, we examined and critically reviewed the most recent advances in viral vector gene therapy obtained from studies using porcine model of atherosclerosis.

LncRNA SLC8A1-AS1 protects against myocardial damage through activation of cGMP-PKG signaling pathway by inhibiting SLC8A1 in mice models of myocardial infarction

Extensive investigations into long noncoding RNAs (lncRNAs) in various diseases and cancers, including acute myocardial infarction (AMI) have been conducted. The current study aimed to investigate the role of lncRNA solute carrier family 8 member A1 antisense RNA 1 (SLC8A1-AS1) in myocardial damage by targeting solute carrier family 8 member A1 (SLC8A1) via cyclic guanosine 3',5'-monophosphate-protein kinase G (cGMP-PKG) signaling pathway in AMI mouse models. Differentially expressed lncRNA in AMI were initially screened and target relationship between lncRNA SLC8A1-AS1 and SLC8A1 was then verified. Infarct size, levels of inflammatory factors, biochemical indicators, and the positive expression of the SLC8A1 protein in AMI were subsequently determined. The expression of SLC8A1-AS1, SLC8A1, PKG1, PKG2, atrial natriuretic peptide, and brain natriuretic peptide was detected to assess the effect of SLC8A1-AS1 on SLC8A1 and cGMP-PKG. The respective contents of superoxide dismutase, lactate dehydrogenase (LDH), and malondialdehyde (MDA) were detected accordingly. Microarray data GSE66360 provided evidence indicating that SLC8A1-AS1 was poorly expressed in AMI. SLC8A1 was verified to be a target gene of lncRNA SLC8A1-AS1. SLC8A1-AS1 upregulation decreased levels of left ventricular end-systolic diameter, -dp/ dt _max , interleukin 1β (IL-1β), IL-6, transforming growth factor α, nitric oxide, inducible nitric-oxide synthase, endothelial nitric-oxide synthase, infarct size, LDH activity and MDA content, and increased IL-10, left ventricular end-diastolic pressure and + dp/ dt _max . Furthermore, the overexpression of SLC8A1-AS1 was noted to elicit an inhibitory effect on the cGMP-PKG signaling pathway via SLC8A1. In conclusion, lncRNA SLC8A1-AS1, by downregulating SLC8A1 and activating the cGMP-PKG signaling pathway, was observed to alleviate myocardial damage, inhibit the release of proinflammatory factors and reduce infarct size, ultimately protecting against myocardial damage.

VEGF-B electrotransfer mediated gene therapy induces cardiomyogenesis in a rat model of cardiac ischemia

Atherosclerosis induced myocardial infarction (MI) continues to be a major public health concern. Regenerative therapies that restore cardiac muscle cells are largely absent. The rate of cardiomyogenesis in adults is insufficient to compensate for MI damage. In this study, we explored the capacity of a gene therapy approach to promote cardiomyogenesis. We hypothesized that VEGF-B, critical during fetal heart development, could promote cardiomyogenesis in adult ischemic hearts. Gene electrotransfer (GET), a physical method of in vivo gene delivery, was adapted to the rat model of MI. Favorable pulsing parameters were then used for delivery of pVEGF-B and compared to a sham control in terms of infarct size, cardiomyocyte proliferation and presence of new cardiomyocytes. Ki67 immunoreactivity was used for proliferation analysis. Newly synthetized DNA was labeled with BrdU to identify new cells post-infarction. Cardiac troponin co-localization indicated proliferating and new cardiomyocytes histologically. Eight weeks post-treatment, GET pVEGF-B treated hearts had significantly smaller infarcts than the sham control group (p < 0.04). Proliferating and new cardiomyocytes were only present in the GET of pVEGF-B group, and absent in the controls. In summary, GET pVEGF-B promoted cardiomyogenesis post-MI, demonstrating for the first time direct evidence of myocardial regeneration post-infarction.

Uncoupling Protein 2 Inhibits Myointimal Hyperplasia in Preclinical Animal Models of Vascular Injury

BACKGROUND

Intracoronary stent restenosis, characterized by excessive smooth muscle cell (SMC) proliferation and myointimal hyperplasia, remains a clinical challenge. Mitochondrial membrane potential has been linked to the proliferative rate of SMCs. This study aimed to screen a critical gene regulating mitochondrial potential and to confirm its effects on myointimal formation in preclinical animal models.

METHODS AND RESULTS

We performed transcriptome screening for genes differentially expressed in ligated versus unligated mouse carotid arteries. We observed that uncoupling protein 2 gene (Ucp2) mRNA, encoding UCP2, was transiently upregulated during the first 3 days after ligation and then significantly downregulated from day 7 through day 21, during which time neointima formed remarkably. The UCP2 protein level also declined after day 7 of ligation. In ligated carotid arteries, Ucp2^-/- mice, compared with wild-type littermates, exhibited accelerated myointimal formation, which was associated with increased superoxide production and can be attenuated by treatment with antioxidant 4-hydroxy-2,2,6,6-tetramethyl-piperidinoxyl (TEMPOL). Knockdown of UCP2 enhanced human aortic SMC migration and proliferation that can also be attenuated by TEMPOL, whereas UCP2 overexpression inhibited SMC migration and proliferation, along with decreased activity of nuclear factor-κB. Moreover, nuclear factor-κB inhibitor attenuated UCP2 knockdown-enhanced SMC proliferation. Adenovirus-mediated overexpression of UCP2 inhibited myointimal formation in balloon-injured carotid arteries of rats and rabbits and in-stent stenosis of porcine coronary arteries. Moreover, UCP2 overexpression also suppressed neointimal hyperplasia in cultured human saphenous vein ex vivo.

CONCLUSIONS

UCP2 inhibits myointimal hyperplasia after vascular injury, probably through suppressing nuclear factor-κB-dependent SMC proliferation and migration, rendering UCP2 a potential therapeutic target against restenosis.

Bolstering cholesteryl ester hydrolysis in liver: A hepatocyte-targeting gene delivery strategy for potential alleviation of atherosclerosis

Current atherosclerosis treatment strategies primarily focus on limiting further cholesteryl esters (CE) accumulation by reducing endogenous synthesis of cholesterol in the liver. No therapy is currently available to enhance the removal of CE, a crucial step to reduce the burden of the existing disease. Given the central role of hepatic cholesteryl ester hydrolase (CEH) in the intrahepatic hydrolysis of CE and subsequent removal of the resulting free cholesterol (FC), in this work, we applied galactose-functionalized polyamidoamine (PAMAM) dendrimer generation 5 (Gal-G5) for hepatocyte-specific delivery of CEH expression vector. The data presented herein show the increased specific uptake of Gal-G5/CEH expression vector complexes (simply Gal-G5/CEH) by hepatocytes in vitro and in vivo. Furthermore, the upregulated CEH expression in the hepatocytes significantly enhanced the intracellular hydrolysis of high density lipoprotein-associated CE (HDL-CE) and subsequent conversion/secretion of hydrolyzed FC as bile acids (BA). The increased CEH expression in the liver significantly increased the flux of HDL-CE to biliary as well as fecal FC and BA. Meanwhile, Gal-G5 did not induce hepatic or renal toxicity. It was also not immunotoxic. Because of these encouraging pre-clinical testing results, using this safe and highly efficient hepatocyte-specific gene delivery platform to enhance the hepatic processes involved in cholesterol elimination is a promising strategy for the alleviation of atherosclerosis.

"Freeze, Don't Move": How to Arrest a Suspect in Heart Failure - A Review on Available GRK2 Inhibitors

Cardiovascular disease and heart failure (HF) still collect the largest toll of death in western societies and all over the world. A growing number of molecular mechanisms represent possible targets for new therapeutic strategies, which can counteract the metabolic and structural changes observed in the failing heart. G protein-coupled receptor kinase 2 (GRK2) is one of such targets for which experimental and clinical evidence are established. Indeed, several strategies have been carried out in place to interface with the known GRK2 mechanisms of action in the failing heart. This review deals with results from basic and preclinical studies. It shows different strategies to inhibit GRK2 in HF in vivo (βARK-ct gene therapy, treatment with gallein, and treatment with paroxetine) and in vitro (RNA aptamer, RKIP, and peptide-based inhibitors). These strategies are based either on the inhibition of the catalytic activity of the kinase (“Freeze!”) or the prevention of its shuttling within the cell (“Don’t Move!”). Here, we review the peculiarity of each strategy with regard to the ability to interact with the multiple tasks of GRK2 and the perspective development of eventual clinical use.

Gene Transfer in Cardiomyocytes Derived from ES and iPS Cells

The advent of human induced pluripotent stem cell (hiPSC) technology has produced patient-specific hiPSC derived cardiomyocytes (hiPSC-CMs) that can be used as a platform to study cardiac diseases and to explore new therapies.The ability to genetically manipulate hiPSC-CMs not only is essential for identifying the structural and/or functional role of a protein but can also provide valuable information regarding therapeutic applications. In this chapter, we describe protocols for culture, maintenance, and cardiac differentiation of hiPSCs. Then, we provide a basic procedure to transduce hiPSC-CMs.

Non-viral magnetic engineering of endothelial cells with microRNA and plasmid-DNA-An optimized targeting approach

Genetic modulation of angiogenesis is a powerful tool for the treatment of multiple disorders. Here, we describe a strategy to produce modified endothelial cells, which can be efficiently magnetically guided. First, we defined optimal transfection conditions with both plasmid and microRNA, using a polyethyleneimine/magnetic nanoparticle-based vector (PEI/MNP), previously designed in our group. Further, two approaches were assessed in vitro: direct vector guidance and magnetic targeting of transfected cells. Due to its higher efficiency, including simulated dynamic conditions, production of miR/PEI/MNP-modified magnetically responsive cells was selected for further detailed investigation. In particular, we have studied internalization of transfection complexes, functional capacities and intercellular communication of engineered cells and delivery of therapeutic miR. Moreover, we demonstrated that 10⁴ miRNA/PEI/MNP-modified magnetically responsive cells loaded with 0.37pg iron/cell are detectable with MRI. Taken together, our in vitro findings show that PEI/MNP is highly promising as a multifunctional tool for magnetically guided angiogenesis regulation.

Vascular endothelial growth factor-A gene electrotransfer promotes angiogenesis in a porcine model of cardiac ischemia

This study aimed to assess safety and therapeutic potential of gene electrotransfer as a method for delivery of plasmid encoding vascular endothelial growth factor A to ischemic myocardium in a porcine model. Myocardial ischemia was induced by surgically occluding the left anterior descending coronary artery in swine. Gene electrotransfer following plasmid encoding vascular endothelial growth factor A injection was performed at four sites in the ischemic region. Control groups either received injections of the plasmid without electrotransfer or injections of saline vehicle. Animals were monitored for seven weeks and hearts were evaluated for angiogenesis, myocardial infarct size, and left ventricular contractility. Arteriograms suggest growth of new arteries as early as two weeks post treatment in electrotransfer animals. There is a significant reduction of infarct area and left ventricular contractility is improved in gene electrotransfer treated group compared to controls. There was no significant difference in mortality of animals treated with gene electrotransfer of plasmid encoding vascular endothelial growth factor A from control groups. Gene delivery of plasmid encoding vascular endothelial growth factor A to ischemic myocardium in a porcine model can be accomplished safely with potential for myocardial repair and regeneration.

A sustained-release drug-delivery system of synthetic prostacyclin agonist, ONO-1301SR: a new reagent to enhance cardiac tissue salvage and/or regeneration in the damaged heart

Cardiac failure is a major cause of mortality and morbidity worldwide, since the standard treatment for cardiac failure in the clinical practice is chiefly to focus on removal of insults against the heart or minimisation of additional factors to exacerbate cardiac failure, but not on regeneration of the damaged cardiac tissue. A synthetic prostacyclin agonist, ONO-1301, has been developed as a long-acting drug for acute and chronic pathologies related to regional ischaemia, inflammation and/or interstitial fibrosis by pre-clinical studies. In addition, poly-lactic co-glycolic acid-polymerised form of ONO-1301, ONO-1301SR, was generated to achieve a further sustained release of this drug into the targeted region. This unique reagent has been shown to act on fibroblasts, vascular smooth muscle cells and endothelial cells in the tissue via the prostaglandin IP receptor to exert paracrinal release of multiple protective factors, such as hepatocyte growth factor, vascular endothelial growth factor or stromal cell-derived factor-1, into the adjacent damaged tissue, which is salvaged and/or regenerated as a result. Our laboratory developed a new surgical approach to treat acute and chronic cardiac failure using a variety of animal models, in which ONO-1301SR is directly placed over the cardiac surface to maximise the therapeutic effects and minimise the systemic complications. This review summarises basic and pre-clinical information of ONO-1301 and ONO-1301SR as a new reagent to enhance tissue salvage and/or regeneration, with a particular focus on the therapeutic effects on acute and chronic cardiac failure and underlying mechanisms, to explore a potential in launching the clinical study.

Cardiovascular adverse effects of targeted antiangiogenic drugs: mechanisms and management

Anticancer treatment has evolved enormously over the last decade. Drugs targeting receptor tyrosine kinases, VEGFR and EGFR have changed the treatment landscape of certain cancers and have shifted the theme of anticancer therapy toward personalized care. However, these newer agents also come with unique side-effect profiles not seen with conventional chemotherapy including serious cardiovascular adverse effects. Hence, meticulous understanding of the adverse effects is crucial in maximizing clinical benefits and minimizing detrimental effects of these newer drugs. We have reviewed the cardiovascular adverse effects of anti-VEGF therapy in this article.

Calcium upregulation by percutaneous administration of gene therapy in patients with cardiac disease (CUPID 2): a randomised, multinational, double-blind, placebo-controlled, phase 2b trial

BACKGROUND

Sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA2a) activity is deficient in the failing heart. Correction of this abnormality by gene transfer might improve cardiac function. We aimed to investigate the clinical benefits and safety of gene therapy through infusion of adeno-associated virus 1 (AAV1)/SERCA2a in patients with heart failure and reduced ejection fraction.

METHODS

We did this randomised, multinational, double-blind, placebo-controlled, phase 2b trial at 67 clinical centres and hospitals in the USA, Europe, and Israel. High-risk ambulatory patients with New York Heart Association class II-IV symptoms of heart failure and a left ventricular ejection fraction of 0·35 or less due to an ischaemic or non-ischaemic cause were randomly assigned (1:1), via an interactive voice and web-response system, to receive a single intracoronary infusion of 1 × 10(13) DNase-resistant particles of AAV1/SERCA2a or placebo. Randomisation was stratified by country and by 6 min walk test distance. All patients, physicians, and outcome assessors were masked to treatment assignment. The primary efficacy endpoint was time to recurrent events, defined as hospital admission because of heart failure or ambulatory treatment for worsening heart failure. Primary efficacy endpoint analyses and safety analyses were done by modified intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01643330.

FINDINGS

Between July 9, 2012, and Feb 5, 2014, we randomly assigned 250 patients to receive either AAV1/SERCA2a (n=123) or placebo (n=127); 243 (97%) patients comprised the modified intention-to-treat population. Patients were followed up for at least 12 months; median follow-up was 17·5 months (range 1·8-29·4 months). AAV1/SERCA2a did not improve time to recurrent events compared with placebo (104 vs 128 events; hazard ratio 0·93, 95% CI 0·53-1·65; p=0·81). No safety signals were noted. 20 (16%) patients died in the placebo group and 25 (21%) patients died in the AAV1/SERCA2a group; 18 and 22 deaths, respectively, were adjudicated as being due to cardiovascular causes.

INTERPRETATION

CUPID 2 is the largest gene transfer study done in patients with heart failure so far. Despite promising results from previous studies, AAV1/SERCA2a at the dose tested did not improve the clinical course of patients with heart failure and reduced ejection fraction. Although we did not find evidence of improved outcomes at the dose of AAV1/SERCA2a studied, our findings should stimulate further research into the use of gene therapy to treat patients with heart failure and help inform the design of future gene therapy trials.

FUNDING

Celladon Corporation.

Cardiac Usage of Reducible Poly(oligo-D-arginine) As a Gene Carrier for Vascular Endothelial Growth Factor Expression

Developments of non-viral carriers have headed toward reducing cytotoxicity, which results from the use of conventional gene carriers, and enhancing gene delivery efficiency. Cys-(d-R9)-Cys repeated reducible poly(oligo-D-arginine) (rPOA) is one of the most efficient non-viral carriers for gene therapy; however, while its efficiency has been verified in the lung and brain, it is necessary to confirm its activity in each organ or tissue since there are differences of gene carrier susceptibility to among tissue types. We therefore tested the compatibility of rPOA in cardiac tissue by in vitro or in vivo experiments and confirmed its high transfection efficiency and low cytotoxicity. Moreover, substantial regenerative effects were observed following transfection with rPOA/pVEGF expression vector complexes (79% decreased infarct size) compared to polyethyleneimine (PEI) (34% decreased infarct size) in a rat myocardial infarction (MI) model. These findings suggest that rPOA efficiently enables DNA transfection in cardiac tissue and can be used as a useful non-viral therapeutic gene carrier for gene therapy in ischemic heart disease.

Cardiovascular genetics: technological advancements and applicability for dilated cardiomyopathy

Genetics plays an important role in the pathophysiology of cardiovascular diseases, and is increasingly being integrated into clinical practice. Since 2008, both capacity and cost-efficiency of mutation screening of DNA have been increased magnificently due to the technological advancement obtained by next-generation sequencing. Hence, the discovery rate of genetic defects in cardiovascular genetics has grown rapidly and the financial threshold for gene diagnostics has been lowered, making large-scale DNA sequencing broadly accessible. In this review, the genetic variants, mutations and inheritance models are briefly introduced, after which an overview is provided of current clinical and technological applications in gene diagnostics and research for cardiovascular disease and in particular, dilated cardiomyopathy. Finally, a reflection on the future perspectives in cardiogenetics is given.

Reprogramming the conduction system: Onward toward a biological pacemaker

Diseases of the cardiac conduction system can be debilitating and deadly. Electronic pacemakers are incredibly effective in the treatment of sinus and AV node dysfunction, yet there remain important limitations and complications. These issues have driven interest in the development of a biological pacemaker. Here, we review experimental progress in animal models and discuss future directions, with a focus on reprogramming endogenous cells in the heart to treat defects of rhythm and conduction.

Codelivery of DNA and siRNA via arginine-rich PEI-based polyplexes

In this study, we formulated polyplexes with different compositions for codelivery of DNA and small-interfering RNA (siRNA). Since DNA and siRNA have distinctive and complementary morphological characteristics (DNA is long and winding and siRNA is short and rigid), we hypothesized that their codelivery using polyplex would enhance each other's transfection. To test this hypothesis, cationic polymer branched polyethylenimine (bPEI) as a standard transfecting agent and its derivative arginine-rich oligopeptide-grafted bPEI modified with polyethylene glycol (P(SiDAAr)5P3), synthesized in our laboratory, were used as carriers for transfection. Polyplexes at different nucleic acid to polymer weight ratios were characterized for transfection in breast cancer sensitive (MCF-7) and resistant (MCF-7/Adr) cell lines. Gene silencing effect of polyplexes was determined in MDA-MB-231-luc-D3H2LN cell line. The results demonstrated that the polyplexes formed with derivative P(SiDAAr)5P3 show significantly lower toxicity compared to polyplexes formed using bPEI. Further, codelivery resulted in 20-fold higher DNA transfection and 2-fold higher siRNA transfection as compared to the respective single nucleotide delivery. DNA transfection was ∼100-fold lower in resistant MCF-7/Adr cells than in sensitive MCF-7 cells. Confocal imaging and flow cytometry data demonstrated that enhanced transfection does not solely depend on DNA's cellular uptake, suggesting that other mechanisms contribute to increased transfection. DNA-co-siRNA delivery could be a promising therapeutic approach to achieve synergistic effects because it can simultaneously target and interfere with multiple regulatory levels in a cell to halt and reverse disease progression.