Combination of electroporation and DNA/dendrimer complexes enhances gene transfer into murine cardiac transplants

Nanomaterials: A Promising Therapeutic Approach for Cardiovascular Diseases

Cardiovascular diseases (CVDs) are a primary cause of death globally. A few classic and hybrid treatments exist to treat CVDs. However, they lack in both safety and effectiveness. Thus, innovative nanomaterials for disease diagnosis and treatment are urgently required. The tiny size of nanomaterials allows them to reach more areas of the heart and arteries, making them ideal for CVDs. Atherosclerosis causes arterial stenosis and reduced blood flow. The most common treatment is medication and surgery to stabilize the disease. Nanotechnologies are crucial in treating vascular disease. Nanomaterials may be able to deliver medications to lesion sites after being infused into the circulation. Newer point-of-care devices have also been considered together with nanomaterials. For example, this study will look at the use of nanomaterials in imaging, diagnosing, and treating CVDs.

Nanotechnology in cardiac stem cell therapy: cell modulation, imaging and gene delivery

The wide arena of applications opened by nanotechnology is multidimensional. It is already been proven that its prominence can continuously influence human life. The role of stem cells in curing degenerative diseases is another major area of research. Cardiovascular diseases are one of the major causes of death globally. Nanotechnology-assisted stem cell therapy could be used to tackle the challenges faced in the management of cardiovascular diseases. In spite of the positive indications and proven potential of stem cells to differentiate into cardiomyocytes for cardiac repair and regeneration during myocardial infarction, this therapeutic approach still remains in its infancy due to several factors such as non-specificity of injected cells, insignificant survival rate, and low cell retention. Attempts to improve stem cell therapy using nanoparticles have shown some interest among researchers. This review focuses on the major hurdles associated with cardiac stem cell therapy and the role of nanoparticles to overcome the major challenges in this field, including cell modulation, imaging, tracking and gene delivery.

This review summarizes the potential challenges present in cardiac stem cell therapy and the major role of nanotechnology to overcome these challenges including cell modulation, tracking and imaging of stem cells.

Theranostic Applications of Nanomaterials in the Field of Cardiovascular Diseases

A large percentage of people are being exposed to mortality due to cardiovascular diseases. Convention approaches have not provided satisfactory outcomes in the management of these diseases. To overcome the limitations of conventional approaches, nanomaterials like nanoparticles, nanotubes, micelles, lipid based nanocarriers, dendrimers, carbon based nano-formulations represent the new aspect of diagnosis and treatment of cardiovascular diseases. The unique inherent properties of the nanomaterials are the major reasons for their rapidly growing demand in the field of medicine. Profound knowledge in the field of nanotechnology and biomedicine is needed for the notable translation of nanomaterials into theranostic cardiovascular applications. In this review, the authors have summarized different nanomaterials which are being extensively used to diagnose and treat the diseases such as coronary heart disease, myocardial infarction, atherosclerosis, stroke and thrombosis.

Gene therapy delivery systems for enhancing viral and nonviral vectors for cardiac diseases: current concepts and future applications

Gene therapy is one of the most promising fields for developing new treatments for the advanced stages of ischemic and monogenetic, particularly autosomal or X-linked recessive, cardiomyopathies. The remarkable ongoing efforts in advancing various targets have largely been inspired by the results that have been achieved in several notable gene therapy trials, such as the hemophilia B and Leber's congenital amaurosis. Rate-limiting problems preventing successful clinical application in the cardiac disease area, however, are primarily attributable to inefficient gene transfer, host responses, and the lack of sustainable therapeutic transgene expression. It is arguable that these problems are directly correlated with the choice of vector, dose level, and associated cardiac delivery approach as a whole treatment system. Essentially, a delicate balance exists in maximizing gene transfer required for efficacy while remaining within safety limits. Therefore, the development of safe, effective, and clinically applicable gene delivery techniques for selected nonviral and viral vectors will certainly be invaluable in obtaining future regulatory approvals. The choice of gene transfer vector, dose level, and the delivery system are likely to be critical determinants of therapeutic efficacy. It is here that the interactions between vector uptake and trafficking, delivery route means, and the host's physical limits must be considered synergistically for a successful treatment course.

In vivo electroporation-mediated gene delivery to the beating heart

Gene therapy may represent a promising alternative strategy for cardiac muscle regeneration. In vivo electroporation, a physical method of gene transfer, has recently evolved as an efficient method for gene transfer. Here, we describe two protocols involving in vivo electroporation for gene transfer to the beating heart.

In vivo electroporation mediated gene delivery to the beating heart

Gene therapy may represent a promising alternative strategy for cardiac muscle regeneration. In vivo electroporation, a physical method of gene transfer, has recently evolved as an efficient method for gene transfer. In the current study, we investigated the efficiency and safety of a protocol involving in vivo electroporation for gene transfer to the beating heart. Adult male rats were anesthetised and the heart exposed through a left thoracotomy. Naked plasmid DNA was injected retrograde into the transiently occluded coronary sinus before the electric pulses were applied. Animals were sacrificed at specific time points and gene expression was detected. Results were compared to the group of animals where no electric pulses were applied. No post-procedure arrhythmia was observed. Left ventricular function was temporarily altered only in the group were high pulses were applied; CK-MB (Creatine kinase) and TNT (Troponin T) were also altered only in this group. Histology showed no signs of toxicity. Gene expression was highest at day one. Our results provide evidence that in vivo electroporation with an optimized protocol is a safe and effective tool for nonviral gene delivery to the beating heart. This method may be promising for clinical settings especially for perioperative gene delivery.

The ability of a collagen/calcium phosphate scaffold to act as its own vector for gene delivery and to promote bone formation via transfection with VEGF(165)

Collagen/calcium phosphate scaffolds have been used for bone reconstruction due to their inherent similarities to the bone extracellular matrix. Calcium phosphate alone has also been used as a non-viral vector for gene delivery. The aim of this study was to determine the capability of a collagen/calcium phosphate scaffold to deliver naked plasmid DNA and mediate transfection in vivo. The second goal of the study was to deliver a plasmid encoding vascular endothelial growth factor(165) (pVEGF(165)) to promote angiogenesis, and hence bone formation, in a mouse intra-femoral model. The delivery of naked plasmid DNA resulted in a 7.6-fold increase in mRNA levels of beta-Galactosidase compared to the delivery of plasmid DNA complexed with a partially degraded PAMAM dendrimer (dPAMAM) in a subcutaneous murine model. When implanted in a muirne intra-femoral model, the delivery of pVEGF(165) resulted in a 2-fold increase in bone volume at the defect site relative to control scaffolds without pVEGF(165). It was concluded that a collagen/calcium phosphate scaffold can mediate transfection without the use of additional transfection vectors and can promote bone formation in a mouse model via the delivery of pVEGF(165).

Dendrimers and DNA: combinations of two special topologies for nanomaterials and biology

Interactions between two precisely defined three-dimensional architectures (DNA and dendrimers) are described. Highly synergetic effects occur, as illustrated in two cases: dendrimers can be used as three-dimensional linkers for oligonucleotides, affording highly sensitive microarrays (biochips), and positively charged dendrimers strongly interact with DNA, allowing penetration inside cells (genetic transfection).

Effect of electroporation on cardiac electrophysiology

Defibrillation shocks are commonly used to terminate life-threatening arrhythmias. According to the excitation theory of defibrillation, such shocks are aimed at depolarizing the membranes of most cardiac cells, resulting in resynchronization of electrical activity in the heart. If shock-induced transmembrane potentials are large enough, they can cause transient tissue damage due to electroporation. In this review, evidence is presented that electroporation of the heart tissue can occur during clinically relevant intensities of the external electrical field and that electroporation can affect the outcome of defibrillation therapy, being both pro- and antiarrhythmic.Here, we present experimental evidence for electroporation in cardiac tissue, which occurs above a threshold of 25 V/cm as evident from propidium iodide uptake, transient diastolic depolarization, and reductions of action potential amplitude and its derivative. These electrophysiological changes can induce tachyarrhythmia, due to conduction block and possibly triggered activity; however, our findings provide the foundation for future design of effective methods to deliver genes and drugs to cardiac tissues, while avoiding possible side effects such as arrhythmia and mechanical stunning.

Cardiovascular gene therapy: current status and therapeutic potential

Gene therapy is emerging as a potential treatment option in patients suffering from a wide spectrum of cardiovascular diseases including coronary artery disease, peripheral vascular disease, vein graft failure and in-stent restenosis. Thus far preclinical studies have shown promise for a wide variety of genes, in particular the delivery of genes encoding growth factors such as vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) to treat ischaemic vascular disease both peripherally and in coronary artery disease. VEGF as well as other genes such as TIMPs have been used to target the development of neointimal hyperplasia to successfully prevent vein graft failure and in-stent restenosis in animal models. Subsequent phase I trials to examine safety of these therapies have been successful with low levels of serious adverse effects, and albeit in the absence of a placebo group some suggestion of efficacy. Phase 2 studies, which have incorporated a placebo group, have not confirmed this early promise of efficacy. In the next generation of clinical gene therapy trials for cardiovascular disease, many parameters will need to be adjusted in the search for an effective therapy, including the identification of a suitable vector, appropriate gene or genes and an effective vector delivery system for a specific disease target. Here we review the current status of cardiovascular gene therapy and the potential for this approach to become a viable treatment option.

Nonviral gene transfer to skeletal, smooth, and cardiac muscle in living animals

The study of muscle physiology has undergone many changes over the past 25 years and has moved from purely physiological studies to those intimately intertwined with molecular and cell biological questions. To ask these questions, it is necessary to be able to transfer genetic reagents to cells both in culture and, ultimately, in living animals. Over the past 10 years, a number of different chemical and physical approaches have been developed to transfect living skeletal, smooth, and cardiac muscle systems with varying success and efficiency. This review provides a survey of these methods and describes some more recent developments in the field of in vivo gene transfer to these various muscle types. Both gene delivery for overexpression of desired gene products and delivery of nucleic acids for downregulation of specific genes and their products are discussed to aid the physiologist, cell biologist, and molecular biologist in their studies on whole animal biology.

Direct electrotransfer of hHGF gene into kidney ameliorates ischemic acute renal failure

In the early phase of kidney transplantation, the transplanted kidney is exposed to insults like ischemia/reperfusion, which is a leading cause of acute renal failure (ARF). ARF in the context of renal transplantation predisposes the graft to developing chronic damage and to long-term graft loss. Hepatocyte growth factor (HGF) has been suggested to support the intrinsic ability of the kidney to regenerate in response to injury by its morphogenic, mitogenic, motogenic and antiapoptotic activities. In the present paper, we examine whether human HGF (hHGF) gene electrotransfer helps in the recovery from ARF in a model of rat renal warm ischemia. We also assess the advantages of this form of gene therapy by direct electroporation of the kidney, given that transplantation offers the possibility of manipulating the organ in vivo. We have compared the therapeutic efficiency of two electroporation methodologies in a rat ARF model. Although they both targeted the same organ, the two methods were applied to different parts of the animal: muscle and kidney. Kidney direct electrotransfer was shown to be more efficient not only in pharmacokinetic but also in therapeutic terms, so it may become a clinically practical alternative in renal transplantation.

Biological applications of dendrimers

In the past year, significant advances have been made in the synthesis and study of glycodendrimers and peptide dendrimers. Application of these dendrimers to the study of carbohydrate-protein and protein-protein interactions has facilitated the understanding of these processes. In addition, dendrimers show great promise as DNA- and drug-delivery systems.