Heat-responsive gene expression for gene therapy

Therapy-inducible vectors are useful for conditional expression of therapeutic genes in gene therapy, which is based on the control of gene expression by conventional treatment modalities. By this approach, combination of chemotherapy, radiation or hyperthermia with gene therapy can result in considerable, additive or synergistic improvement of therapeutic efficacy. This concept has been successfully tested in particular for gene therapy of cancer. The identification of efficient heat-responsive gene promoters provided the rationale for heat-regulated gene therapy. The objective of this review is to provide insights into the cellular mechanisms of heat-shock response, as prerequisite for therapeutic actions of hyperthermia and into the field of heat-responsive gene therapy. Furthermore, the major strategies of heat-responsive gene therapy systems in particular for cancer treatment are summarized. The developments for heat-responsive vector systems for in vitro and in vivo approaches are discussed. This review will provide an overview for this gene therapy strategy and its potential for multimodal therapeutic concepts in the clinic.     

Therapeutic angiogenesis with gene transfection for ischemic heart disease

Recent advances in modern medicine have made it possible to understand disease processes at the genetic level and to apply this knowledge to new treatment strategies. Genetic engineering studies conducted in the field of cardiovascular medicine have led to the use of gene therapy as a new means for treating ischemic heart disease. The incidence of ischemic heart disease, with underlying conditions of diabetes mellitus and arteriosclerosis, has increased in recent years and is a major cause of myocardial infarction, cerebrovascular disease and death. Patients with these diseases often do not respond satisfactorily to conventional treatments. Consequently attention has turned to the area of revascularization therapy utilizing the introduction of genes. (c) 2001 Prous Science. All rights reserved.     

Cell therapy for the treatment of chronic ischemic heart disease

Over the last decade, much was learned about the biology of several types of stem and progenitor cells. It has become apparent that various cell sources may have the capacity to promote cardiomyogenesis and new blood vessel formation through different mechanisms, forming the rationale for cell-based therapy in patients with chronic ischemic heart disease. After initial clinical studies have provided evidence for safety of cell administration, larger randomized trials demonstrated variable effects on myocardial perfusion and contractile performance. Although cell-based therapy is a promising strategy for the treatment of myocardial disease, many questions remain to be answered with respect to the optimal cell type, delivery route and mechanism of action in order to improve the outcome of cardiac cell therapy. This paper aims to provide an overview of the methods available to apply cell-based therapy in chronic ischemic myocardial disease. The different cell types that have been tested in (pre)clinical trials and their proposed mechanism of action will be discussed, along with the possible routes of cell delivery. Furthermore, the experience from experimental and clinical studies will be summarized, and innovative strategies to enhance the efficacy of cell therapy, for example by improving cell retention and survival, will be reviewed.     

Stem cell therapy in ischemic heart disease

Coronary artery disease (CAD) remains the leading cause of death in the Western world. The high impact of its main sequelae, acute myocardial infarction and congestive heart failure (CHF), on the quality of life of patients and the cost of health care drives the search for new therapies. The recent finding that stem cells contribute to neovascularization and possibly improve cardiac function after myocardial infarction makes stem cell therapy the most highly active research area in cardiology. Although the concept of stem cell therapy may revolutionize heart failure treatment, several obstacles need to be addressed. To name a few: 1) Which patient population should be considered for stem cell therapy? 2) What type of stem cell should be used? 3) What is the best route for cell delivery? 4) What is the optimum number of cells that should be used to achieve functional effects? 5) Is stem cell therapy safer and more effective than conventional therapies? The published studies vary significantly in design, making it difficult to draw conclusions on the efficacy of this treatment. For example, different models of ischemia, species of donors and recipients, techniques of cell delivery, cell types, cell numbers and timing of the experiments have been used. However, these studies highlight the landmark concept that stem cell therapy may play a major role in treating cardiovascular diseases in the near future. It should be noted that stem cell therapy is not limited to the treatment of ischemic cardiac disease. Non-ischemic cardiomyopathy, peripheral vascular disease, and aging may be treated by stem cells. Stem cells could be used as vehicle for gene therapy and eliminate the use of viral vectors. Finally, stem cell therapy may be combined with pharmacological, surgical, and interventional therapy to improve outcome. Here we attempt a systematic overview of the science of stem cells and their effects when transplanted into ischemic myocardium.     

急性缺血性脑血管病早期诊断和对策

急性缺血性脑血管病是我国的常见病、多发病,是威胁人们健康的主要疾病之一.利用CT灌注成像联合CTA、磁共振灌注成像联合磁共振弥散加权成像等现代影像学技术,超早期(6 h内)诊断,及时进行溶栓、抗凝及抗血小板凝集等有效治疗,可以防止疾病的进展,减轻神经功能缺损和改善预后.     

Augmentation of erythropoietin enhancer-mediated hypoxia-inducible gene expression by co-transfection of a plasmid encoding hypoxia-inducible factor 1alpha for ischemic tissue targeting gene therapy

Therapeutic angiogenesis with gene encoding vascular endothelial growth factor (VEGF) is a potential treatment for ischemic diseases. However, VEGF expression should be tightly regulated to avoid side effects such as tumor growth. Previously, our group developed the erythropoietin (Epo) enhancer-SV40 promoter system for hypoxia-specific gene expression. In the present study, the activity of the Epo enhancer-SV40 promoter system was further enhanced without significant decrease in its specificity by co-transfection of the hypoxia-inducible factor 1alpha (HIF1alpha) gene. pSV-HIF1alpha was constructed by the insertion of the HIF1alpha cDNA into pSI. At a 1:1 ratio, co-transfection of pSV-HIF1alpha and pEpo-SV-Luc increased the promoter activity of the Epo enhancer-SV40 promoter system, showing at least three times higher gene expression under hypoxia as compared with the pEpo-SV-Luc single-plasmid transfection. Furthermore, co-transfection showed significant hypoxia specificity. Also, co-transfection of pEpo-SV-VEGF with pSV-HIF1alpha showed the enhanced VEGF expression without loss of hypoxia specificity, as compared with pEpo-SV-VEGF single-plasmid transfection. Furthermore, pSV-HIF1alpha induced the endogenous hypoxia-responsive genes such as angiopoietin-1, which would be beneficial for therapeutic angiogenesis. Therefore, with hypoxia specificity and higher gene expression, co-transfection of pSV-HIF1alpha and pEpo-SV-VEGF may be useful for ischemia targeting gene therapy.     

Viral-based gene delivery and regulated gene expression for targeted cancer therapy

Importance of the field: Cancer is both a major health concern and a care-cost issue in the US and the rest of the world. It is estimated that there will be a total of 1,479,350 new cancer cases and 562,340 cancer deaths in 2009 within the US alone. One of the major obstacles in cancer therapy is the ability to target specifically cancer cells. Most existing chemotherapies and other routine therapies (such as radiation therapy and hormonal manipulation) use indiscriminate approaches in which both cancer cells and non-cancerous surrounding cells are treated equally by the toxic treatment. As a result, either the cancer cell escapes the toxic dosage necessary for cell death and consequently resumes replication, or an adequate lethal dose that kills the cancer cell also causes the cancer patient to perish. Owing to this dilemma, cancer- or organ/tissue-specific targeting is greatly desired for effective cancer treatment and the reduction of side effect cytotoxicity within the patient.

Areas covered in this review: In this review, the strategies of targeted cancer therapy are discussed, with an emphasis on viral-based gene delivery and regulated gene expression.

What the reader will gain: Numerous approaches and updates in this field are presented for several common cancer types.

Take home message: A summary of existing challenges and future directions is also included.     

Nitric oxide synthase gene therapy for cardiovascular disease

Gene therapy refers to the transfer of specific genes to the host tissue to intervene in a disease process, with resultant alleviation of the symptoms of a particular disease. Cardiovascular gene transfer is not only a powerful technique for studying the function of specific genes in cardiovascular biology and pathobiology, but also a novel and promising strategy for treating cardiovascular diseases. Since the mid-1990s, nitric oxide synthase (NOS), the enzyme that catalyzes the formation of nitric oxide (NO) from L-arginine, has received considerable attention as a potential candidate for cardiovascular gene therapy, because NO exerts critical and diverse functions in the cardiovascular system, and abnormalities in NO biology are apparent in a number of cardiovascular disease processes including cerebral vasospasm, atherosclerosis, postangioplasty restenosis, transplant vasculopathy, hypertension, diabetes mellitus, impotence and delayed wound healing. There are three NOS isoforms, i.e., endothelial (eNOS), neuronal (nNOS) and inducible (iNOS). All three NOS isoforms have been used in cardiovascular gene transfer studies with encouraging results. This review will discuss the rationale of NOS gene therapy in different cardiovascular disease settings and summarize the results of experimental NOS gene therapy from various animal models of cardiovascular disease to date.     

Prospects for gene therapy in lung disease.

The past decade has brought significant advances in the field of gene therapy for both inherited and acquired diseases, especially with regard to respiratory disease. Barriers to gene transfer posed by the lung have led to the development of modifications of both vector and host in an attempt to increase the efficiency of transfer. Recently, progress has been made in both laboratory and clinical studies of gene therapy for cystic fibrosis, alpha1-antitrypsin deficiency and lung cancer.     

序贯抗凝治疗缺血性脑血管病的临床疗效

目的 探讨序贯抗凝治疗缺血性脑血管病的临床疗效。方法 40例频繁发生的短暂性脑缺血发作及进展性卒中患者，均经一般抗凝等治疗病情继续进展，给予口服华法林抗凝，进行疗效评价。结果 40例患者痊愈率45％；显效率25％；好转率20％，无效率10％。结论 临床序贯抗凝治疗缺血性脑血管病，治愈好转率高，后遗症少，是值得临床广泛应用的一种可行的治疗方法。     

Antibodies for targeted gene therapy: extracellular gene targeting and intracellular expression

Antibody genes of human origin and human antibodies directed against human proteins have become widely available in recent years. These are valuable reagents for gene therapy applications, in which the use of human proteins and genes allows for increased therapeutic benefit. Engineered human antibodies can be used in gene therapy both as a component of a gene delivery system and as a therapeutic gene. As the targeting moiety of a gene delivery system, the antibody should meet certain criteria that have been previously determined from other clinical applications of antibodies. These include bioavailability, specificity for the target cell, and rapid clearance. In addition, if repeat delivery of therapeutic genes is going to be needed, then gene delivery vectors should be non-immunogenic to allow repeated administration. The use of human antibodies in this application should therefore be superior to approaches which use rodent-derived antibodies. Another application of antibodies in gene therapy is the use of antibodies expressed inside the cell (intrabodies) as therapeutic agents. The power of the immune system to rearrange a limited set of genes to create recognition sites for any known molecule is well documented. The ability to harness this information and use these highly specific binding molecules as medicines to inhibit an unwanted cellular function is a promising advance in the field of molecular medicine, and in particular, in the field of intracellular immunization.     

Women and heart disease — Physiologic regulation of gene delivery and expression: Bioreducible polymers and ischemia-inducible gene therapies for the treatment of ischemic heart disease

Ischemic heart disease (IHD) is the leading cause of death in the United States today. This year over 750,000 women will have a new or recurrent myocardial infarction. Currently, the mainstay of therapy for IHD is revascularization. Increasing evidence, however, suggests that revascularization alone is insufficient for the longer-term management of many patients with IHD. To address these issues, innovative therapies that extend beyond revascularization to protection of the myocyte and preservation of ventricular function are required. The emergence of gene therapy and proteomics offers the potential for innovative prophylactic and treatment strategies for IHD. The goal of our research is to develop therapeutic gene constructs for the treatment of myocardial ischemia that are clinically safe and effective. Toward this end, we describe the development of physiologic regulation of gene delivery and expression using bioreducible polymers and ischemia-inducible gene therapies for the potential treatment of ischemic heart disease in women.     

缺血性脑卒中的抗凝治疗

抗凝治疗是缺血性脑卒中(IS)的重要治疗手段之一,但IS急性期的抗凝治疗颇多争议.华法林是目前惟一明确对房颤患者脑卒中预防有效的口服抗凝药,然而该药的使用尚有多种限制.本文综述抗凝药及其在IS急性期治疗中的应用以及新型抗凝药对脑卒中的预防作用.     

Towards a gene therapy for cystic fibrosis lung disease

Gene therapy for the treatment of the pulmonary manifestations of cystic fibrosis (CF) has been at the forefront of gene therapy research over the last several years. During this time, however, despite immense efforts, controlled clinical trials with CF patients have failed to demonstrate significant and reproducible `correction' of the CF bioelectrical functional defect. The target tissue requiring `correction' in CF lung disease is the respiratory epithelium that lines the airways of the lung, and evidence is now emerging that the epithelium has evolved to elude the uptake of potential pathogens, including viruses, bacteria and gene transfer vectors. The majority of studies with gene transfer to the airway epithelium have used the adenovirus as the gene delivery vector, since high efficiency gene transfer to airway epithelial cells grown in culture can be demonstrated. However, when these vectors are tested in the airways of animals and humans in vivo, the efficiency of gene transfer is low. It is likely that these observations are not limited to adenoviral vectors (Ad), since similar gene transfer discrepancies are observed with a range of vector systems being developed for CF lung gene therapy. Therefore, this update will focus on the factors responsible for efficient gene transfer to airway epithelial cells in vitro and, using Ad as examples, discuss the development of `targeted' gene transfer vectors that may overcome the resistance of the airway epithelium in vivo to efficient gene transfer.