PubMed Health⌕ Search

Biomedical subjects

E G Nabel

Publications and source records attributed to E G Nabel.

At least 73 records · Page 4Linked to original sources
PubMed1994

Safety and toxicity of catheter gene delivery to the pulmonary vasculature in a patient with metastatic melanoma.

One approach to gene therapy for human cancer is transcatheter injection of DNA liposomes into tumor masses. To determine the feasibility of selective delivery of recombinant genes by a catheter to the pulmonary vasculature in humans, a patient with melanoma received two treatments of HLA-B7 plasmid DNA complexed to cationic liposomes into a right posterior basal pulmonary artery associated with a mass lesion. The treatments were well tolerated. No adverse respiratory, cardiac, immunologic, or other organ toxicities were detected. The delivery of recombinant genes by catheter may be a useful modality to treat human malignancy and other diseases.

Adenocarcinoma↗
PubMed1994

Gene transfer and vascular disease.

Major advances in molecular biology over the past decade have increased our understanding of how genes are expressed and regulated in mammalian cells in vivo. This knowledge has been translated to investigations of the molecular and cellular biology of the cardiovascular system. Gene transfer, the introduction of a recombinant gene into host somatic cells, has become a useful tool for studying gene structure and function. It can be used to identify regulatory sequences that control gene expression. Transfer of a gene into a new cellular environment provides a means to determine gene function. These methods also allow investigators to introduce new genes into intact animals, permitting the development of animal models of human disease and investigations of gene function in vivo. The field of gene transfer and vascular disease is emerging as a new approach for studying the pathophysiology of vascular disease and for developing potential new genetic treatments for these disorders. In this review, we discuss the methods for gene transfer, how these methods can be employed to investigate the pathophysiology of cardiovascular diseases, and the potential for the development of molecular genetic treatments for human vascular diseases. The focus will be on cardiovascular diseases, although the principles may be applied to other disorders. In summary, gene transfer represents a new approach to applying molecular biology to the study and treatment of human disease.

Gene Transfer Techniques↗
PubMed1994

Transcriptional regulation of NF-kappa B2: evidence for kappa B-mediated positive and negative autoregulation.

NF-kappa B is an inducible transcription factor complex which regulates the expression of a variety of genes which are involved in the immune, inflammatory, and acute-phase responses. The maintenance of NF-kappa B activity in stimulated cells requires ongoing protein synthesis, suggesting several modes of regulation. In this report, we have characterized the transcriptional regulation of one family member, NF-kappa B2. The genomic structure and sequence of NF-kappa B2 revealed the presence of two promoters and at least four kappa B regulatory elements, which mediate responsiveness to phorbol myristate acetate and tumor necrosis factor alpha. Similar to other NF-kappa B family members, NF-kappa B2 is positively autoregulated. In contrast to other family members, we find that kappa B elements in the NFKB2 promoter can also mediate transcriptional repression in the absence of NF-kappa B. We identified a nuclear complex which binds specifically to a subset of kappa B-related sites but not to the canonical kappa B element. Because of its putative inhibitory or repressive effect, this binding activity has been termed Rep-kappa B. This mechanism of repressing basal NF-kappa B2 transcription in an inactivated state enables the cell to tightly control NF-kappa B2 activity. These data demonstrate that a novel mode of kappa B-dependent regulation is mediated by specific kappa B sites in the NFKB2 promoter.

Base Sequence↗
PubMed1994

Catheter-mediated pulmonary vascular gene transfer and expression.

The study and treatment of pulmonary diseases may be greatly facilitated by in vivo expression of specific recombinant genes in the pulmonary vasculature and lung parenchyma. To evaluate the feasibility of gene transfer to the pulmonary vasculature, cationic liposomes and adenoviral vectors encoding a human placental alkaline phosphatase (hpAP) gene were delivered into a pulmonary artery of 24 pigs by percutaneous right heart catheterization. Pulmonary tissue was harvested within 20 minutes or 5, 14, or 28 days later and was analyzed for gene transfer and expression. Five days after exposure to liposomes or adenoviral vectors, transfer of DNA and expression of mRNA were demonstrated in transfected lung tissue. Recombinant alkaline phosphatase protein was observed in both the vasculature and in alveolar septa but not in the bronchi. Expression of hpAP protein was observed at 5 days, was diminished at 14 days, and was absent 28 days after gene transfer with both liposome and adenoviral vectors. No major adverse effects of gene expression were detected by histological examination of the transfected lung segments compared with control segments. Gene transfer to the lung by either vector was not associated with significant biochemical abnormalities or histological changes 5, 14, or 28 days later in other organs, including carotid artery, heart, liver, spleen, kidney, skeletal muscle, ovary, and testes. These studies demonstrate that after intravascular gene delivery to the lung, recombinant genes are expressed in the vasculature and alveoli. This approach may provide a useful model for the experimental study of pulmonary vascular diseases, including pulmonary fibrosis and pulmonary thrombosis disorders.

Adenoviridae↗
PubMed1993

Direct gene transfer with DNA-liposome complexes in melanoma: expression, biologic activity, and lack of toxicity in humans.

Direct gene transfer offers the potential to introduce DNA encoding therapeutic proteins to treat human disease. Previously, gene transfer in humans has been achieved by a cell-mediated ex vivo approach in which cells from the blood or tissue of patients are genetically modified in the laboratory and subsequently returned to the patient. To determine the feasibility and safety of directly transferring genes into humans, a clinical study was performed. The gene encoding a foreign major histocompatibility complex protein, HLA-B7, was introduced into HLA-B7-negative patients with advanced melanoma by injection of DNA-liposome complexes in an effort to demonstrate gene transfer, document recombinant gene expression, and determine the safety and potential toxicity of this therapy. Six courses of treatment were completed without complications in five HLA-B7-negative patients with stage IV melanoma. Plasmid DNA was detected within biopsies of treated tumor nodules 3-7 days after injection but was not found in the serum at any time by using the polymerase chain reaction. Recombinant HLA-B7 protein was demonstrated in tumor biopsy tissue in all five patients by immunochemistry, and immune responses to HLA-B7 and autologous tumors could be detected. No antibodies to DNA were detected in any patient. One patient demonstrated regression of injected nodules on two independent treatments, which was accompanied by regression at distant sites. These studies demonstrate the feasibility, safety, and therapeutic potential of direct gene transfer in humans.

Aged↗
PubMed1993

Direct transfer of transforming growth factor beta 1 gene into arteries stimulates fibrocellular hyperplasia.

The arterial wall responds to thrombosis or mechanical injury through the induction of specific gene products that increase cellular proliferation and connective tissue formation. These changes result in intimal hyperplasia that is observed in restenosis and the early phases of atherosclerosis. Transforming growth factor beta 1 (TGF-beta 1) is a secreted multi-functional protein that plays an important role in embryonal development and in repair following tissue injury. However, the function of TGF-beta 1 in vascular cell growth in vivo has not been defined. In this report, we have evaluated the role of TGF-beta 1 in the pathophysiology of intimal and medial hyperplasia by gene transfer of an expression plasmid encoding active TGF-beta 1 into porcine arteries. Expression of TGF-beta 1 in normal arteries resulted in substantial extracellular matrix production accompanied by intimal and medial hyperplasia. Increased procollagen, collagen, and proteoglycan synthesis in the neointima was demonstrated by immunohistochemistry relative to control transfected arteries. Expression of TGF-beta 1 induced a distinctly different program of gene expression and biologic response from the platelet-derived growth factor B (PDGF B) gene: procollagen synthesis induced by TGF-beta 1 was greater, and cellular proliferation was less prominent. These findings show that TGF-beta 1 differentially modulates extracellular matrix production and cellular proliferation in the arterial wall in vivo and could play a reparative role in the response to arterial injury.

Animals↗
PubMed1993

Recombinant fibroblast growth factor-1 promotes intimal hyperplasia and angiogenesis in arteries in vivo.

The prototype members of the heparin-binding fibroblast growth factor (FGF) family, acidic FGF (FGF-1) and basic FGF (FGF-2), are among the growth factors that act directly on vascular cells to induce endothelial cell growth and angiogenesis. In vivo, the role of the FGF prototypes in vascular pathology has been difficult to determine. We report here the introduction, by direct gene transfer into porcine arteries, of a eukaryotic expression vector encoding a secreted form of FGF-1. This somatic transgenic model defines gene function in the arterial wall in vivo. FGF-1 expression induced intimal thickening in porcine arteries 21 days after gene transfer, in contrast to control arteries transduced with an Escherichia coli beta-galactosidase gene. Where there was substantial intimal hyperplasia, neocapillary formation was detected in the expanded intima. These findings suggest that FGF-1 induces intimal hyperplasia in the arterial wall in vivo and, through its ability to stimulate angiogenesis in the neointima, FGF-1 could stimulate neovascularization of atherosclerotic plaques. Potentially, gene transfer of FGF-1 could also be used as a genetic intervention to improve blood flow to ischaemic tissues in selected clinical settings.

Animals↗
PubMed1993

Differential regulation of vascular cell adhesion molecule 1 gene expression by specific NF-kappa B subunits in endothelial and epithelial cells.

Vascular cell adhesion molecule 1 (VCAM-1) is expressed in both endothelial and epithelial cell types, where it contributes to lymphocyte migration to sites of inflammation. Its expression is regulated by cytokines, in part through two kappa B-like regulatory elements. Because NF-kappa B can be composed of multiple alternative subunits with differential effects on gene expression, the role of different specific NF-kappa B family members subunits in VCAM-1 regulation is unknown. In this report, we define the contribution of different NF-kappa B family members to VCAM-1 gene regulation. We show that both kappa B sites in the VCAM-1 enhancer are required to optimally stimulate gene expression, but the enhancer is differentially regulated by specific combinations of NF-kappa B subunits. At low concentrations, RelA(p65) acted in concert with the approximately 50-kDa product of p105 NF-kappa B, NF-kappa B1(p50), to stimulate transcription, and at high concentrations, RelA(p65) alone stimulated the VCAM-1 promoter. In contrast, NF-kappa B2 inhibited functional activation of the VCAM reporter by p65. Consistent with this finding, an additional binding complex was detected by using recombinant NF-kappa B2(p49)/RelA(p65) with radiolabeled VCAM kappa B site probes. Interestingly, the human immunodeficiency virus enhancer responded differently to stimulation by NF-kappa B subunits, with optimal response to p49(100)/p65. Analysis of NF-kappa B mRNA in human umbilical vein endothelial cells revealed that nfkb1, nfkb2, and relA NF-kappa B but not c-rel were induced by tumor necrosis factor alpha and lipopolysaccharide, which also induce VCAM-1. These data suggest that specific subunits of NF-kappa B regulate VCAM-1 and differentially activate other genes in these cells.

Animals↗
PubMed1993

Recombinant platelet-derived growth factor B gene expression in porcine arteries induce intimal hyperplasia in vivo.

Platelet-derived growth factor (PDGF) B chain induces cell proliferation in vitro and is associated with arterial lesions that cause cardiovascular disease. However, it has been difficult to document the biological response to PDGF B gene expression in arteries in vivo. To determine the biologic effects of this growth factor in vivo, we have introduced an eukaryotic expression vector plasmid encoding recombinant PDGF B by direct gene transfer into porcine iliofemoral arteries using DNA liposome complexes. The presence of PDGF B plasmid DNA and expression of recombinant mRNA were confirmed by polymerase chain reaction analysis, and recombinant PDGF protein was demonstrated by immunohistochemistry. Intimal thickening was observed in porcine arteries 21 days following transfection with the recombinant PDGF B gene compared with arteries transduced with a control gene, E. coli beta-galactosidase. An eightfold increase in intimal to medial ratio was present in PDGF B gene transfected arteries compared with control transfected arteries (P = 0.001). This study suggests that expression of a recombinant PDGF B gene in vivo can play a role in the induction of intimal hyperplasia, which can lead to cardiovascular diseases.

Animals↗
PubMed1992

Transduction of a foreign histocompatibility gene into the arterial wall induces vasculitis.

Autoimmune vasculitis represents a disease characterized by focal inflammation within arteries at multiple sites in the vasculature. Therapeutic interventions in this disease are empirical and often unsuccessful, and the mechanisms of immune injury are not well-defined. The direct transfer of recombinant genes and their expression in the arterial wall provides an opportunity to explore the pathogenesis and treatment of vascular disease. In this report, an animal model for vasculitis has been developed. Inflammation has been elicited by direct gene transfer of a foreign class I major histocompatibility complex gene, HLA-B7, to specific sites in porcine arteries. Transfer and expression of this recombinant gene was confirmed by a polymerase chain reaction and immunohistochemistry, and cytolytic T cells specific for HLA-B7 were detected. These findings demonstrate that expression of a recombinant gene in the vessel wall can induce a focal immune response and suggest that vessel damage induced by cell-mediated immune injury can initiate vasculitis.

Animals↗
PubMed1992

Gene transfer in vivo with DNA-liposome complexes: safety and acute toxicity in mice.

DNA can be introduced into a variety of cell types after formation of liposomal complexes with cationic lipids. In this report, conditions have been established to optimize the production of DNA-liposome complexes that efficiently transfect cells. The safety and toxicity of this method of gene delivery have been assessed after in vivo administration, either by intravenous or direct intratumor injection. Nine to eleven days after intravenous injection, DNA was found primarily in heart and lung tissue by PCR analysis. No abnormalities were evident from histologic examination of tissue, examination of tissue-specific serum enzymes, routine biochemical parameters, or electrocardiographic monitoring. DNA-liposome complexes can therefore be used for the delivery of recombinant genes in vivo with minimal toxicity.

Animals↗
PubMed1992

Gene transfer in vivo with DNA-liposome complexes: lack of autoimmunity and gonadal localization.

Direct gene transfer into localized arterial segments can be performed in vivo by transfection with DNA-liposome complexes. This technique holds promise for the treatment of human diseases, including malignancy and cardiovascular disorders. We have previously characterized the potential toxicity of this form of treatment in mice in vivo (Stewart et al., 1992). In this report, we examined two issues relevant to long-term expression of foreign recombinant genes: (i) the potential for autoimmune damage to major organs and (ii) DNA localization in gonadal tissue. Autoimmunity and toxicity of allogeneic major histocompatibility (MHC) gene transfer was assessed in mice after induction of an immune response to a recombinant murine class I MHC gene by direct gene transfer in vivo. Histological examination of brain, heart, lung, liver, kidney, spleen, and skeletal muscle revealed no clinically significant immunopathology or organ damage. The toxicity of gene delivery by DNA liposomes was also analyzed in pigs and rabbits in vivo. No histopathology was observed following the introduction of plasmids encoding several different gene products, and analysis of serum following DNA liposome delivery revealed no abnormalities of serum biochemical parameters. The potential for transfer of recombinant DNA into testes and ovary in animals was evaluated by the polymerase chain reaction. Although evidence of recombinant plasmid was consistently observed in transfected, but not untransfected, arterial sites and occasionally in lung, kidney, spleen, and liver, no plasmid DNA was detected in testes or ovary. These studies suggest that uptake of recombinant DNA following direct gene transfer by liposomal transfection in major organs is not associated with autoimmunity, toxicity, or gonadal localization.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Epicardial coronary artery responses to acetylcholine are impaired in hypertensive patients.

Hypertension is a risk factor for coronary atherosclerosis possibly via an adverse effect on the vascular endothelium. Endothelium-mediated relaxation is impaired in animal models of hypertension. However, the effects of hypertension on human coronary artery endothelial cell function are unknown. To test whether endothelium-mediated relaxation is impaired in the coronary arteries of patients with hypertension, we studied 14 patients with essential hypertension requiring therapy and 15 nonhypertensive control patients undergoing cardiac catheterization. All had angiographically normal, smooth-appearing coronary arteries. Patients were matched for age and other coronary atherosclerosis risk factors. To assess endothelial cell function, the endothelium-dependent vasodilator acetylcholine (ACh, 0.01, 0.1, and 1.0 microM) and the endothelium-independent vasodilator nitroglycerin (40 micrograms) were selectively infused into the left anterior descending or circumflex coronary artery. Diameter change (expressed as percent) was assessed using quantitative angiography. There was a marked vasoconstrictor response to serial doses of ACh in hypertensive patients (-7%, -21%, and -27%) compared with control patients (-4%, -5%, and -7%) (p less than 0.02). The vasodilator response to nitroglycerin was preserved in hypertensive patients (+29%) and control patients (+25%) (p = NS), suggesting that endothelial cell dysfunction accounted for the differences in response to ACh. Thus, patients with hypertension have an accentuated coronary vasoconstrictor response to ACh, suggesting that endothelium-mediated regulation of coronary vascular tone is impaired by essential hypertension. This may reflect more generalized coronary endothelial changes contributing to the pathogenesis of atherosclerosis as well as hypertension.

Acetylcholine↗
PubMed1991

Biology of the impaired endothelium.

The endothelium is a regulatory organ that mediates hemostasis, contractility, cellular proliferation, and inflammatory mechanisms in the vessel wall. Injury to the endothelium from hypertension, smoking, hyperlipidemia, and diabetes mellitus disrupts normal regulatory properties and results in abnormal endothelial cell function. Clinically, endothelial cell dysfunction can be manifested as vasospasm, thrombus formation, atherosclerosis, or restenosis. The normal hemostatic properties of the endothelium include the maintenance of a nonadhesive luminal surface, antithrombotic properties, anticoagulant properties, and fibrinolytic properties. The endothelial cell regulates smooth muscle cell contractility by the production of relaxing and constricting factors in response to physiologic stimuli. Endothelial cell injury is also an initial event in the development of atherosclerosis and restenosis by facilitating platelet adhesion and aggregation and by signaling the release of mitogens from platelets, macrophages, and endothelial cells, which stimulate smooth muscle cell proliferation. In addition, endothelial cells undergo morphologic and functional alterations in response to cytokine signals, which may contribute to the pathogenesis of vasculitis and atherosclerosis. In sum, the normal endothelium performs many regulatory functions which become altered when the endothelium is injured.

Animals↗