Evolving revascularization approaches for myocardial ischemia

Natural Herbal Medicine as a Treatment Strategy for Myocardial Infarction through the Regulation of Angiogenesis

Methods

We conducted a literature search on the bioactive components of medicinal plants and their effects on angiogenesis after MI. We searched for articles in Web of Science, MEDLINE, PubMed, Scopus, Google Scholar, and China National Knowledge Infrastructure databases before April 2021.

Results

In this article, we summarized the mechanisms by which copper ions, microRNA, Akt1, inflammation, oxidative stress, mitochondria, and pericytes are involved in angiogenesis after myocardial infarction. In addition, we reviewed the angiogenic effects of natural herbal medicines such as Salvia miltiorrhiza Bunge Bunge, Carthamus tinctorius L., Pueraria lobata, Astragalus, Panax ginseng C.A. Mey., Panax notoginseng (Burkill) F.H. Chen, Cinnamomum cassia (L.) J. Presl, Rehmannia glutinosa (Gaertn.) DC., Leonurus japonicus Houtt, Scutellaria baicalensis Georgi., and Geum macrophyllum Willd.

Conclusions

Some herbs have the effect of promoting angiogenesis. In the future, natural proangiogenic drugs may become candidates for the treatment of cardiovascular diseases.

MR fluoroscopy in vascular and cardiac interventions (review)

Vascular and cardiac disease remains a leading cause of morbidity and mortality in developed and emerging countries. Vascular and cardiac interventions require extensive fluoroscopic guidance to navigate endovascular catheters. X-ray fluoroscopy is considered the current modality for real time imaging. It provides excellent spatial and temporal resolution, but is limited by exposure of patients and staff to ionizing radiation, poor soft tissue characterization and lack of quantitative physiologic information. MR fluoroscopy has been introduced with substantial progress during the last decade. Clinical and experimental studies performed under MR fluoroscopy have indicated the suitability of this modality for: delivery of ASD closure, aortic valves, and endovascular stents (aortic, carotid, iliac, renal arteries, inferior vena cava). It aids in performing ablation, creation of hepatic shunts and local delivery of therapies. Development of more MR compatible equipment and devices will widen the applications of MR-guided procedures. At post-intervention, MR imaging aids in assessing the efficacy of therapies, success of interventions. It also provides information on vascular flow and cardiac morphology, function, perfusion and viability. MR fluoroscopy has the potential to form the basis for minimally invasive image-guided surgeries that offer improved patient management and cost effectiveness.

Novel minicircle vector for gene therapy in murine myocardial infarction

BACKGROUND

Conventional plasmids for gene therapy produce low-level and short-term gene expression. In this study, we develop a novel nonviral vector that robustly and persistently expresses the hypoxia-inducible factor-1 alpha (HIF-1alpha) therapeutic gene in the heart, leading to functional benefits after myocardial infarction.

METHODS AND RESULTS

We first created minicircles (MC) carrying double-fusion reporter gene consisting of firefly luciferase and enhanced green fluorescent protein (Fluc-eGFP) for noninvasive measurement of transfection efficiency. Mouse C2C12 myoblasts and normal FVB/N mice were used for in vitro and in vivo confirmation, respectively. Bioluminescence imaging showed stable MC gene expression in the heart for >12 weeks and the activity level was 5.6+/-1.2-fold stronger than regular plasmid at day 4 (P<0.01). Next, we created MC carrying HIF-1alpha (MC-HIF-1alpha) therapeutic gene for treatment of myocardial infarction. Adult FVB/N mice underwent left anterior descending ligation and were injected intramyocardially with: (1) MC-HIF-1alpha; (2) regular plasmid carrying HIF-1alpha (PL-HIF-1alpha) as positive control; and (3) PBS as negative control (n=10/group). Echocardiographic study showed a significantly greater improvement of left ventricular ejection fraction in the MC group (51.3%+/-3.6%) compared to regular plasmid group (42.3%+/-4.1%) and saline group (30.5%+/-2.8%) at week 4 (P<0.05 for both). Histology demonstrated increased neoangiogenesis in both treatment groups. Finally, Western blot showed MC express >50% higher HIF-1alpha level than regular plasmid.

CONCLUSIONS

Taken together, this is the first study to our knowledge to demonstrate that MC can significantly improve transfection efficiency, duration of transgene expression, and cardiac contractility. Given the serious drawbacks associated with most viral vectors, we believe this novel nonviral vector can be of great value for cardiac gene therapy protocols.

Enhancement of noncoronary collateral circulation: the hypothesis of an alternative treatment for ischemic heart disease

The internal thoracic arteries (ITAs) are a source of "noncoronary collateral circulation" (NCCC), or "noncoronary collateral blood flow" (NCCBF). The hypothesis herein is that enhancement of NCCC may represent an alternative means of myocardial blood supply: (1) Ligature of the ITAs creates a local hypertensive status and increases the perfusion pressure within the channels leading to the heart; (2) Myocardial ischemic stimulus diverts most ITA-related collateral flow to the heart rather than to the chest wall; (3) The ITAs may develop neo-collaterals owing to their ischemia-related plastic potential; (4) Angiogenic growth factor administration within the ITAs enhances neo-collateral development. These elements may pave the way for a new field of cardiovascular research aimed at enhancing NCCC as a new therapeutic option for ischemic heart disease.

Demographics and changes in medical/interventional treatment of coronary artery disease patients over a 3.5-year period in Japan: the Japanese Coronary Artery Disease Study: trend examination

BACKGROUND

Cardiovascular medicine has undergone rapid changes in recent years, but there are insufficient reports using large cohorts regarding these changes for Japanese coronary artery disease (CAD) patients. Hence, a large-scale prospective observational study was needed.

METHODS AND RESULTS

A total of 36,298 patients were registered over 6 periods. Patients with hypertension, hyperlipidemia, obesity, and impaired glucose tolerance increased in number, while those with old myocardial infarction (MI), smoking habit, and family history of CAD decreased. Regarding the trends in interventional procedures, stent use increased in both the whole cohort and the acute MI subgroup, while the use of only medical control decreased. Regarding prescription trends, angiotensin-receptor blockers increased while nitrates decreased.

CONCLUSIONS

In a period of 3.5 years, significant changes were observed for both interventional procedures and medication, which might be related to the well-timed compliance of physicians with published evidence. However, these changes were not related to changes in the event rates, at least over the short term. Although careful attention should be paid in interpreting the results, because this is an observational study and the background of patients in each cohort might have been heterogeneous, such investigations should be constantly conducted for evidence-based practice.

Recent advances in minimal-access cardiac surgery using robotic-enhanced surgical systems

Recent advances in interventional cardiology and cardiac surgery have changed traditional therapeutic algorithms by altering indications, timing and patterns of referral for subsequent surgical treatment. Developments in coronary revascularization have focused on reducing both surgical invasiveness and trauma. Patients with significant comorbid pathologies, those undergoing reinterventions and especially the elderly may benefit from such hybrid procedures by avoiding cardiopulmonary bypass and a midline sternotomy. Minimally invasive techniques have revolutionized cardiothoracic surgery by increasing patient satisfaction and by reducing surgical trauma, hospital stay, and consequently overall costs. There are, however, limitations, but robot-assisted surgery endeavors to minimize these technical hindrances and thus allow better and more accurate surgical practice whilst minimizing surgical trauma.

Radionuclide reporter gene imaging for cardiac gene therapy

INTRODUCTION

In the field of cardiac gene therapy, angiogenic gene therapy has been most extensively investigated. The first clinical trial of cardiac angiogenic gene therapy was reported in 1998, and at the peak, more than 20 clinical trial protocols were under evaluation. However, most trials have ceased owing to the lack of decisive proof of therapeutic effects and the potential risks of viral vectors. In order to further advance cardiac angiogenic gene therapy, remaining open issues need to be resolved: there needs to be improvement of gene transfer methods, regulation of gene expression, development of much safer vectors and optimisation of therapeutic genes. For these purposes, imaging of gene expression in living organisms is of great importance. In radionuclide reporter gene imaging, "reporter genes" transferred into cell nuclei encode for a protein that retains a complementary "reporter probe" of a positron or single-photon emitter; thus expression of the reporter genes can be imaged with positron emission tomography or single-photon emission computed tomography. Accordingly, in the setting of gene therapy, the location, magnitude and duration of the therapeutic gene co-expression with the reporter genes can be monitored non-invasively. In the near future, gene therapy may evolve into combination therapy with stem/progenitor cell transplantation, so-called cell-based gene therapy or gene-modified cell therapy.

CONCLUSION

Radionuclide reporter gene imaging is now expected to contribute in providing evidence on the usefulness of this novel therapeutic approach, as well as in investigating the molecular mechanisms underlying neovascularisation and safety issues relevant to further progress in conventional gene therapy.

Positron Emission Tomography Reporter Gene Imaging in the Myocardium: For Monitoring of Angiogenic Gene Therapy in Ischemic Heart Disease

Cardiac angiogenic gene therapy has emerged as a novel treatment approach for patients with intractable ischemic heart disease, aiming at facilitating neovascularization to augment blood flow in the ischemic myocardium by introducing genes encoding for angiogenic factors. While several clinical trials for cardiac angiogenic gene therapy are currently in progress, there remains a discrepancy between impressive preclinical results and their limited clinical findings. On the other hand, positron emission tomography (PET) reporter gene imaging has been developed to monitor expression of transgenes in vivo. PET reporter genes encode for proteins that retain complementary positron-emitting tracers (PET reporter probes), and theoretically any therapeutic gene can be linked and coexpressed with an appropriate PET reporter gene. Consequently, PET reporter gene imaging with a PET reporter probe affords external determination of the location, magnitude, and duration of expression of therapeutic genes noninvasively. Since PET imaging can be performed in various species ranging from mice to humans, in vivo cardiac PET reporter gene imaging could play a critical role in identifying the "missing link" as a powerful translational research tool. In this article, we discuss the role of PET reporter gene imaging in basic and clinical research on cardiac angiogenic gene therapy.

Therapeutic angiogenesis for coronary artery disease: clinical trials of proteins, plasmids, adenovirus and stem cells

Therapeutic angiogenesis represents a molecular and cellular approach to the treatment of coronary artery disease that may be an alternative or additive to traditional pharmacology and interventional cardiology. The goal of angiogenic therapy is to activate endogenous angiogenic and arteriogenic pathways and stimulate revascularization of ischemic myocardial tissue. The feasibility of such a strategy has now been established through the results of studies over the past decade, and clinical trials involving more than 1000 patients have been implemented. In this review the results from these trials will be discussed, tracing the progression of the technology from the delivery of recombinant proteins to gene and stem-cell therapies. It is the opinion of the author that neither proteins nor genes delivered by transient expression vectors will provide an optimal therapy. Rather, the future of this approach lies with regulated genes delivered by permanent vector systems and possibly engineered into stem cells.

Minimal access coronary revascularisation without cardiopulmonary bypass—the impact of robotic technology in the current clinical practice

Recent advances in interventional cardiology and cardiac surgery have changed the traditional therapeutic algorithms by altering indications, timing and patterns of referral for subsequent surgical treatment. The traditional longitudinal sternomy incision has been the surgical approach of choice for multi-vessel coronary revascularisation. Drawbacks of this incision include potential postoperative morbidity, which translates to a prolonged postoperative length of stay. The combination of minimally invasive direct coronary artery bypass (MIDCAB) with percutaneous transluminal coronary angioplasty (PTCA) or stenting (a hybrid approach) is an alternative therapeutic method for patients with multivessel coronary artery disease. Recent advances in percutaneous interventions have attempted to address the problem of re-stenosis, initially through the deployment of bare metal intra-coronary stents and, more recently, with drug-eluting stents. Developments in coronary revascularisation have focused on reducing both surgical invasiveness and trauma. Patients with significant co-morbid pathologies, the ones undergoing re-interventions, and especially the elderly may benefit from such hybrid procedures by avoiding cardiopulmonary bypass and midline sternotomy. Minimally invasive techniques have revolutionized cardiothoracic surgery by increasing patient satisfaction and by reducing surgical trauma, hospital stay and consequently overall costs. There are however limitations. Robot assisted surgery endeavours to minimise these technical hindrances and so allow better and more accurate surgical practice whilst minimising surgical trauma.

Sleeping Beauty Transposon‐Mediated Gene Therapy for Prolonged Expression

The Sleeping Beauty (SB) transposon system represents a new vector for non-viral gene transfer that melds advantages of viruses and other forms of naked DNA transfer. The transposon itself is comprised of two inverted terminal repeats of about 340 base pairs each. The SB system directs precise transfer of specific constructs from a donor plasmid into a mammalian chromosome. The excision of the transposon from a donor plasmid and integration into a chromosomal site is mediated by Sleeping Beauty transposase, which can be delivered to cells vita its gene or its mRNA. As a result of its integration in chromosomes, and its lack of viral sequences that are often detected by poorly understood cellular defense mechanisms, a gene in a chromosomally integrated transposon can be expressed over the lifetime of a cell. SB transposons integrate nearly randomly into chromosomes at TA-dinucleotide base pairs although the sequences flanking the TAs can influence the probability of integration at a given site. Although random integration of vectors into human genomes is often thought to raise significant safety issues, evidence to date does not indicate that random insertions of SB transposons represent risks that are equal to those of viral vectors. Here we review the activities of the SB system in mice used as a model for human gene therapy, methods of delivery of the SB system, and its efficacy in ameliorating disorders that model human disease.

Angiogenesis and lymphangiogenesis: highlights of the past year

PURPOSE OF REVIEW

The purpose of this review is not to provide an extensive overview of well-established mechanisms of angiogenesis and lymphangiogenesis but rather to highlight several recent key studies that constituted a significant conceptual or medical advancement to the field during the past year or so. The authors apologize for their inability, because of space restrictions, to reference all other relevant work of the past or previous years.

RECENT FINDINGS

In 1993, fewer than 400 studies on angiogenesis were published. During the past year alone, more than 4000 angiogenesis studies were reported, making angiogenesis one of the most rapidly growing fields. Moreover, the first studies on lymphangiogenesis were published only a couple of years ago. A milestone in the field in the past year has been the first successful report that the angiogenesis inhibitor bevacizumab (Avastin), an antibody against vascular endothelial growth factor, prolonged the survival of colorectal and renal cancer patients in phase 3 clinical trials. This remarkable achievement provides great promise and hope for the future development of therapeutic strategies to inhibit or stimulate angiogenesis.

SUMMARY

The intensive search for antiangiogenic and proangiogenic mechanisms during the past decade is starting to translate into clinical promise. Further discovery of novel pathways and concepts in angiogenesis may lead to the optimization and refinement of current strategies to improve the clinical benefit and therapeutic safety for a vast number of patients with angiogenesis-related disease.

Current options in the management of coronary artery disease

World Health Organization projections suggest that, for the foreseeable future, coronary artery disease (CAD) will remain the largest element of global disease burden, reflecting the aging of the population. Recent American College of Cardiology/American Heart Association guidelines estimate that 16.6 million Americans currently have stable angina. Chronic stable angina is associated with significant morbidity and mortality, thus highlighting the need for accurate and early detection and treatment. Clinical examination is the single most important step in evaluating risk. Age, sex, pain type, coexisting diabetes mellitus, hypertension, or known vascular disease are powerful predictors of prognosis and, except for special patient groups, are more reliable than ambulatory electrocardiographic recording, exercise testing, or electron-beam computed tomography. Cost-effective methods for screening the general population for "silent" risk factors predisposing them to atherosclerotic disease in later life are nevertheless required. Aspirin, beta-blockers, angiotensin-converting enzyme inhibitors, and lipid-lowering agents are currently the backbone of pharmacologic therapy, supplemented by lifestyle changes aimed at promoting exercise, weight reduction, and increased fruit and vegetable intake. However, side effects of chronic drug treatment, especially for those taking multidrug regimens, may affect quality of life and are the principal reason for poor compliance. Coronary bypass surgery and angioplasty are frequently used interventional procedures for CAD, although they can be invasive and costly, and they often need to be repeated. Current options for the management of CAD have their limitations, thus confirming the appropriateness of continuing the search for improved therapies to reverse the disease process and reduce the global burden.