Quality-of-life measurement in advanced cancer: assessing the individual

PURPOSE

Despite the increasing importance of assessing quality of life (QoL) in patients with advanced cancer, relatively little is known about individual patient's perceptions of the issues contributing to their QoL. The Schedule for the Evaluation of Individual Quality of Life (SEIQoL) and the shorter SEIQoL-Direct Weighting (SEIQoL-DW) assess individualized QoL using a semistructured interview technique. Here we report findings from the first administration of the SEIQoL and SEIQoL-DW to patients with advanced incurable cancer.

PATIENTS AND METHODS

QoL was assessed on a single occasion using the SEIQoL and SEIQoL-DW in 80 patients with advanced incurable cancer.

RESULTS

All patients were able to complete the SEIQoL-DW, and 78% completed the SEIQoL. Of a possible score of 100, the median QoL global score was as follows: SEIQoL, 61 (range, 24 to 94); SEIQoL-DW, 60.5 (range, 6 to 95). Psychometric data for SEIQoL indicated very high levels of internal consistency (median r =.90) and internal validity (median R(2) = 0.88). Patients' judgments of their QoL were unique to the individual. Family concerns were almost universally rated as more important than health, the difference being significant when measured using the SEIQoL-DW (P =.002).

CONCLUSION

Patients with advanced incurable cancer were very good judges of their QoL, and many patients rated their QoL as good. Judgments were highly individual, with very high levels of consistency and validity. The primacy given to health in many QoL questionnaires may be questioned in this population. The implications of these findings are discussed with regard to clinical assessment and advance directives.

Antibody blockade of thrombospondin accelerates reendothelialization and reduces neointima formation in balloon-injured rat carotid artery

BACKGROUND

Remodeling of the extracellular matrix plays an important role during the pathogenesis of atherosclerosis and restenosis. The matrix glycoprotein thrombospondin-1 (TSP1) inhibits endothelial cell proliferation and migration in vitro. In contrast, TSP1 facilitates the growth and migration of cultured vascular smooth muscle cells. Accordingly, we investigated the hypothesis that administration of anti-TSP1 antibody could facilitate reendothelialization and inhibit neointimal thickening in balloon-injured rat carotid artery.

METHODS AND RESULTS

Sprague-Dawley rats were subjected to left common carotid artery denudation, after which arteries were treated with C6.7 anti-TSP1 or control antibody. Evans blue dye staining 2 weeks after injury disclosed significantly increased reendothelialization in arteries treated with C6.7 antibody compared with the control group, and this effect was associated with increased number of proliferating cell nuclear antigen-positive endothelial cells. In contrast, treatment with C6.7 antibody decreased the number of proliferating cell nuclear antigen-positive vascular smooth muscle cells in the injured arterial wall. Neointimal thickening was correspondingly attenuated to a statistically significant degree in arteries receiving C6.7 antibody versus the control group at both the 2-week and 4-week time points.

CONCLUSIONS

Intra-arterial delivery of antibody against TSP1 facilitated reendothelialization and reduced neointimal lesion formation after balloon denudation.

Continuous subcutaneous infusion of morphine vs. hydromorphone: a controlled trial

Seventy-four patients were included in a double-blind, randomized, controlled trial comparing the analgesic efficacy and adverse effects of hydromorphone and morphine delivered by continuous subcutaneous infusion. Patients completed the Memorial Pain Assessment Card and a checklist of opioid-related adverse effects immediately before commencing subcutaneous infusion and 24, 48, and 72 hours later. An assessment tool was developed for the 60 patients who were too ill to complete their own questionnaire. The tool demonstrated excellent inter-rater reliability. Thirty-four percent of patients in the hydromorphone group and 27% of those in the morphine group died before completion of the study (P = 0.66). The hydromorphone group required more analgesia for breakthrough pain in the first 24 hours of the study (P = 0.03) and had a greater improvement in the behavior of frowning on movement and the comfort visual analogue scale (P = 0.08) over the course of the study. Adverse effects were rare and similar in both groups. This study found hydromorphone to be at least as effective as morphine when delivered by continuous subcutaneous infusion.

Impaired collateral vessel development associated with reduced expression of vascular endothelial growth factor in ApoE-/- mice

BACKGROUND

The impact of disordered lipid metabolism on collateral vessel development was studied in apolipoprotein (apo)E-/- mice with unilateral hindlimb ischemia.

METHODS AND RESULTS

Hindlimb blood flow and capillary density were markedly reduced in apoE-/- mice versus C57 controls. This was associated with reduced expression of vascular endothelial growth factor (VEGF) in the ischemic limbs of apoE-/- mice. Cell-specific immunostaining localized VEGF protein expression to skeletal myocytes and infiltrating T cells in the ischemic limbs of C57 mice; in contrast, T-cell infiltrates in ischemic limbs of apoE-/- mice were severely reduced. The critical contribution of T cells to VEGF expression and collateral vessel growth was reinforced by the finding of accelerated limb necrosis in athymic nude mice with operatively induced hindlimb ischemia. Adenoviral VEGF gene transfer to apoE-/- mice resulted in marked augmentation of hindlimb blood flow and capillary density.

CONCLUSIONS

These findings thus underscore the extent to which hyperlipidemia adversely affects native collateral development but does not preclude augmented collateral vessel growth in response to exogenous cytokines. Moreover, results obtained in the apoE-/- and athymic nude mice imply a critical role for infiltrating T cells as a source of VEGF in neovascularization of ischemic tissues.

Reduced intimal thickening following alpha(v)beta3 blockade is associated with smooth muscle cell apoptosis

The adhesion integrin alpha(v)beta3 is expressed by both activated endothelial cells (ECs) and smooth muscle cells (SMCs). Peptide and antibody antagonists of alpha(v)beta3 have been shown to block angiogenesis by initiating unscheduled programmed cell death of proliferating ECs. The present study was designed to determine if antagonism of alpha(v)beta3 immediately following balloon injury might similarly lead to programmed cell death among activated SMCs, and thereby inhibit intimal thickening. LM609, a monoclonal antibody antagonist of alpha(v)beta3, was administered locally and/or systemically immediately after balloon angioplasty in a rabbit model of vascular injury. Immunohistochemical studies documented that LM609, even when administered systemically, localized to sites of vascular injury. LM609 administered immediately following balloon injury of the external iliac artery markedly reduced intimal thickening at 2 and 4 wk post-injury. Apoptosis was abundant where balloon injury resulted in expression of alpha(v)beta3. At both 2 and 4 wk, re-endothelialization at the site of balloon injury was not retarded in LM609-treated rabbits versus controls. Thus, blockade of alpha(v)beta3 inhibits intimal thickening when administered immediately following balloon injury. This favorable impact on neointimal thickening is associated with apoptosis of activated SMCs expressing alpha(v)beta3. These findings may explain the reduction in restenosis observed clinically following beta3 integrin blockade.

Ischemia- and cytokine-induced mobilization of bone marrow-derived endothelial progenitor cells for neovascularization

Endothelial progenitor cells (EPCs) have been isolated from circulating mononuclear cells in human peripheral blood and shown to be incorporated into foci of neovascularization, consistent with postnatal vasculogenesis. We determined whether endogenous stimuli (tissue ischemia) and exogenous cytokine therapy (granulocyte macrophage-colony stimulating factor, GM-CSF) mobilize EPCs and thereby contribute to neovascularization of ischemic tissues. The development of regional ischemia in both mice and rabbits increased the frequency of circulating EPCs. In mice, the effect of ischemia-induced EPC mobilization was demonstrated by enhanced ocular neovascularization after cornea micropocket surgery in mice with hindlimb ischemia compared with that in non-ischemic control mice. In rabbits with hindlimb ischemia, circulating EPCs were further augmented after pretreatment with GM-CSF, with a corresponding improvement in hindlimb neovascularization. There was direct evidence that EPCs that contributed to enhanced corneal neovascularization were specifically mobilized from the bone marrow in response to ischemia and GM-CSF in mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase transcriptionally regulated by the endothelial cell-specific Tie-2 promoter. These findings indicate that circulating EPCs are mobilized endogenously in response to tissue ischemia or exogenously by cytokine therapy and thereby augment neovascularization of ischemic tissues.

Rescue of diabetes-related impairment of angiogenesis by intramuscular gene therapy with adeno-VEGF

Diabetes is a major risk factor for coronary and peripheral artery diseases. Although diabetic patients often present with advanced forms of these diseases, it is not known whether the compensatory mechanisms to vascular ischemia are affected in this condition. Accordingly, we sought to determine whether diabetes could: 1) impair the development of new collateral vessel formation in response to tissue ischemia and 2) inhibit cytokine-induced therapeutic neovascularization. Hindlimb ischemia was created by femoral artery ligation in nonobese diabetic mice (NOD mice, n = 20) and in control C57 mice (n = 20). Hindlimb perfusion was evaluated by serial laser Doppler studies after the surgery. In NOD mice, measurement of the Doppler flow ratio between the ischemic and the normal limb indicated that restoration of perfusion in the ischemic hindlimb was significantly impaired. At day 14 after surgery, Doppler flow ratio in the NOD mice was 0.49+/-0.04 versus 0.73+/-0.06 for the C57 mice (P< or =0.005). This impairment in blood flow recovery persisted throughout the duration of the study with Doppler flow ratio values at day 35 of 0.50+/-0.05 versus 0.90+/-0.07 in the NOD and C57 mice, respectively (P< or =0.001). CD31 immunostaining confirmed the laser Doppler data by showing a significant reduction in capillary density in the NOD mice at 35 days after surgery (302+/-4 capillaries/mm2 versus 782+/-78 in C57 mice (P< or =0.005). The reduction in neovascularization in the NOD mice was the result of a lower level of vascular endothelial growth factor (VEGF) in the ischemic tissues, as assessed by Northern blot, Western blot and immunohistochemistry. The central role of VEGF was confirmed by showing that normal levels of neovascularization (compared with C57) could be achieved in NOD mice that had been supplemented for this growth factor via intramuscular injection of an adenoviral vector encoding for VEGF. We conclude that 1) diabetes impairs endogenous neovascularization of ischemic tissues; 2) the impairment in new blood vessel formation results from reduced expression of VEGF; and 3) cytokine supplementation achieved by intramuscular adeno-VEGF gene transfer restores neovascularization in a mouse model of diabetes.

Age-dependent impairment of angiogenesis

BACKGROUND

The effect of aging on angiogenesis in ischemic vascular disease has not been studied. Accordingly, we investigated the hypothesis that angiogenesis is impaired as a function of age.

METHODS AND RESULTS

Forty days after the resection of 1 femoral artery, collateral vessel development was significantly impaired in old (aged 4 to 5 years; n=7) versus young (aged 6 to 8 months; n=6) New Zealand White (NZW) rabbits on the basis of reduced hindlimb perfusion (ischemic: normal blood pressure ratio=0.58+/-0.05 versus 0.77+/-0.06; P<0.005), reduced number of angiographically visible vessels (angiographic score=0.48+/-0.05 versus 0.70+/-0.05; P<0.01), and lower capillary density in the ischemic limb (130.3+/-5.8/mm2 versus 171.4+/-9.5/mm2; P<0.001). Angiogenesis was also impaired in old (aged 2 years) versus young (aged 12 weeks) mice as shown by reduced hindlimb perfusion (measured by laser Doppler imaging) and lower capillary density (353.0+/-14.3/mm2 versus 713.3+/-63.4/mm2; P<0.01). Impaired angiogenesis in old animals was the result of impaired endothelial function (lower basal NO release and decreased vasodilation in response to acetylcholine) and a lower expression of vascular endothelial growth factor (VEGF) in ischemic tissues (by Northern blot, Western blot, and immunohistochemistry). When recombinant VEGF protein was administered to young and old rabbits, both groups exhibited a significant and similar increase in blood pressure ratio, angiographic score, and capillary density.

CONCLUSIONS

Angiogenesis responsible for collateral development in limb ischemia is impaired with aging; responsible mechanisms include age-related endothelial dysfunction and reduced VEGF expression. Advanced age, however, does not preclude augmentation of collateral vessel development in response to exogenous angiogenic cytokines.

Restoration of E2F expression rescues vascular endothelial cells from tumor necrosis factor-alpha-induced apoptosis

BACKGROUND

Normally, quiescent endothelial cells (EC) line the inner surface of arteries and protect against thrombosis and neointimal growth. A variety of noxious stimuli, including balloon angioplasty, may compromise EC integrity, thereby initiating proliferation and triggering the local release of cytokines, including tumor necrosis factor-alpha (TNF-alpha).

METHODS AND RESULTS

In vivo blockade of TNF-alpha using a soluble receptor molecule results in accelerated reendothelialization at sites of balloon angioplasty, suggesting an important physiological role of TNF-alpha in attenuating regrowth of endothelium after balloon angioplasty. Our studies reveal that TNF-alpha, an apoptosis-inducing cytokine, induces G1 cell-cycle arrest in proliferating EC. Quiescent EC are relatively immune to TNF-induced apoptosis versus proliferating EC, which display repression of the E2F transcription factor coincident with TNF-induced apoptosis and cell-cycle arrest. We also show that in this setting, E2F overexpression exerts a survival effect in proliferating EC and restores cell-cycle progression, in direct contrast to results of prior reports, which revealed that deregulated expression of E2F in normally cycling cells induces apoptosis.

CONCLUSIONS

These data demonstrate that TNF-induced apoptosis is highly dependent on cell-cycle activity and that E2F can function as survival factor under certain conditions.

Tie2 receptor ligands, angiopoietin-1 and angiopoietin-2, modulate VEGF-induced postnatal neovascularization

Angiopoietin-1 (Ang1) has been recently identified as the major physiological ligand for the tyrosine kinase receptor Tie2 and assigned responsibility for recruiting and sustaining periendothelial support cells. Angiopoietin-2 (Ang2) was found to disrupt blood vessel formation in the developing embryo by antagonizing the effects of Ang1 and Tie2 and was thus considered to represent a natural Ang1/Tie2 inhibitor. In vivo effects of either angiopoietin on postnatal neovascularization, however, have not been previously described. Accordingly, we used the cornea micropocket assay of neovascularization to investigate the impact of angiopoietins on neovascularization in vivo. Neither Ang1 nor Ang2 alone promoted neovascularization. Pellets containing vascular endothelial growth factor (VEGF) alone induced corneal neovascularity extending from the limbus across the cornea. Addition of Ang 1 to VEGF (Ang1+VEGF) produced an increase in macroscopically evident perfusion of the corneal neovasculature without affecting macroscopic measurements of length (0.58+/-0.03 mm) or circumferential neovascularity (136+/-10 degrees). In contrast, pellets containing Ang2+VEGF promoted significantly longer (0.67+/-0.05 mm) and more circumferential (160+/-15degrees) neovascularity than VEGF alone or Ang1+VEGF (P<0.05). Excess soluble Tie2 receptor (sTie2-Fc) precluded modulation of VEGF-induced neovascularization by both Ang2 and Ang1. Fluorescent microscopic findings demonstrated enhanced capillary density (fluorescence intensity, 2.55+/-0.23 e+9 versus 1.23+/-0.17 e+9, P<0.01) and increased luminal diameter of the basal limbus artery (39.0+/-2.8 versus 27.9+/-1.3 microm, P<0.01) for Ang1+VEGF compared with VEGF alone. In contrast to Ang1+VEGF, Ang2+VEGF produced longer vessels and, at the tip of the developing capillaries, frequent isolated sprouting cells. In the case of Ang2+VEGF, however, luminal diameter of the basal limbus artery was not increased (26.7+/-1.9 versus 27.9+/-1.3, P=NS). These findings constitute what is to our knowledge the first direct demonstration of postnatal bioactivity associated with either angiopoietin. In particular, these results indicate that angiopoietins may potentiate the effects of other angiogenic cytokines. Moreover, these findings provide in vivo evidence that Ang1 promotes vascular network maturation, whereas Ang2 works to initiate neovascularization.

Vascular endothelial growth factor-C (VEGF-C/VEGF-2) promotes angiogenesis in the setting of tissue ischemia

Recently, vascular endothelial growth factor-C (VEGF-C or VEGF-2) was described as a specific ligand for the endothelial receptor tyrosine kinases VEGFR-2 and VEGFR-3. In vivo data, limited to constitutive overexpression in transgenic mice, have been interpreted as evidence that the growth-promoting effects of VEGF-C are restricted to development of the lymphatic vasculature. The current studies were designed to test the hypothesis that constitutive expression of VEGF-C in adult animals promotes angiogenesis. In vitro, VEGF-C exhibited a dose-dependent mitogenic and chemotactic effect on endothelial cells, particularly for microvascular endothelial cells (72% and 95% potency, respectively, compared with VEGF-A/VEGF-1). VEGF-C stimulated release of nitric oxide from endothelial cells and increased vascular permeability in the Miles assay; the latter effect was attenuated by pretreatment with the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester. Both VEGFR-2 and VEGFR-3 receptors were shown to be expressed in human saphenous vein and internal mammary artery. The potential for VEGF-C to promote angiogenesis in vivo was then tested in a rabbit ischemic hindlimb model. Ten days after ligation of the external iliac artery, VEGF-C was administered as naked plasmid DNA (pcVEGF-C; 500 microg) from the polymer coating of an angioplasty balloon (n = 8 each) or as recombinant human protein (rhVEGF-C; 500 microg) by direct intra-arterial infusion. Physiological and anatomical assessments of angiogenesis 30 days later showed evidence of therapeutic angiogenesis for both pcVEGF-C and rhVEGF-C. Hindlimb blood pressure ratio (ischemic/normal) after pcVEGF-C increased to 0.83 +/- 0.03 after pcVEGF-C versus 0.59 +/- 0.04 (P < 0.005) in pGSVLacZ controls and to 0.76 +/- 0.04 after rhVEGF-C versus 0.58 +/- 0.03 (P < 0.01) in control rabbits receiving rabbit serum albumin. Doppler-derived iliac flow reserve was 2.7 +/- 0.1 versus 2.0 +/- 0.2 (P < 0.05) for pcVEGF-C versus LacZ controls and 2.9 +/- 0.3 versus 2.1 +/- 0.2 (P < 0.05) for rhVEGF-C versus albumin controls. Neovascularity was documented by angiography in vivo (angiographic scores: 0.85 +/- 0.05 versus 0.51 +/- 0.02 (P < 0.001) for plasmid DNA and 0.74 +/- 0.08 versus 0.53 +/- 0.03 (P < 0.05) for protein), and capillary density (per mm2) was measured at necropsy (252 +/- 12 versus 183 +/- 10 (P < 0.005) for plasmid DNA and 229 +/- 20 versus 164 +/- 20 (P < 0.05) for protein). In contrast to the results of gene targeting experiments, constitutive expression of VEGF-C in adult animals promotes angiogenesis in the setting of limb ischemia. VEGF-C and its receptors thus constitute an apparently redundant pathway for postnatal angiogenesis and may represent an alternative to VEGF-A for strategies of therapeutic angiogenesis in patients with limb and/or myocardial ischemia.

Prospective evaluation of new and old criteria to discriminate between supraventricular and ventricular tachycardia in implantable defibrillators

This study was designed to evaluate the ability to distinguish between supraventricular tachycardias (SVTs) and ventricular tachycardias (VTs) based on onset, stability, and width criteria in an implantable defibrillator. Inappropriate detection of atrial fibrillation and sinus tachycardia is a common problem in patients with implantable defibrillators. The onset, stability, and width criteria were studied in 17 patients who underwent implantation of a Medtronic 7218C implantable defibrillator by inducing sinus tachycardia and atrial fibrillation. Additional data on the width criteria was obtained by pacing at separate sites in both the left and right ventricle. Patients were studied at different times for up to 6 months to determine any changes in the criteria. The onset and stability criteria caused inappropriate detections in 36% and 12% of the episodes, respectively. The addition of the width criteria decreased the inappropriate detection using the onset and stability criteria to 5% and 2%, respectively. Pacing from the RV apex, RV outflow tract, and LV apex was appropriately detected as wide in 76%, 41%, and 94%, respectively. The width criteria changed over time in individual patients, but was stable by 6 months in all but one patient. No single criterion is satisfactory for distinguishing between SVT and VT in this patient population, but the combination of criteria seems to provide better discrimination. The width criteria can change dramatically over time and needs to be monitored carefully. Newer algorithms will need to be developed to allow better detection of supraventricular tachycardias.

Nitric oxide synthase modulates angiogenesis in response to tissue ischemia

We tested the hypothesis that endothelial nitric oxide synthase (eNOS) modulates angiogenesis in two animal models in which therapeutic angiogenesis has been characterized as a compensatory response to tissue ischemia. We first administered L-arginine, previously shown to augment endogenous production of NO, to normal rabbits with operatively induced hindlimb ischemia. Angiogenesis in the ischemic hindlimb was significantly improved by dietary supplementation with L-arginine, compared to placebo-treated controls; angiographically evident vascularity in the ischemic limb, hemodynamic indices of limb perfusion, capillary density, and vasomotor reactivity in the collateral vessel-dependent ischemic limb were all improved by oral L-arginine supplementation. A murine model of operatively induced hindlimb ischemia was used to investigate the impact of targeted disruption of the gene encoding for ENOS on angiogenesis. Angiogenesis in the ischemic hindlimb was significantly impaired in eNOS-/- mice versus wild-type controls evaluated by either laser Doppler flow analysis or capillary density measurement. Impaired angiogenesis in eNOS-/- mice was not improved by administration of vascular endothelial growth factor (VEGF), suggesting that eNOS acts downstream from VEGF. Thus, (a) eNOS is a downstream mediator for in vivo angiogenesis, and (b) promoting eNOS activity by L-arginine supplementation accelerates in vivo angiogenesis. These findings suggest that defective endothelial NO synthesis may limit angiogenesis in patients with endothelial dysfunction related to atherosclerosis, and that oral L-arginine supplementation constitutes a potential therapeutic strategy for accelerating angiogenesis in patients with advanced vascular obstruction.

Mouse model of angiogenesis

Neovascularization of ischemic muscle may be sufficient to preserve tissue integrity and/or function and may thus be considered to be therapeutic. The regulatory role of vascular endothelial growth factor (VEGF) in therapeutic angiogenesis was suggested by experiments in which exogenously administered VEGF was shown to augment collateral blood flow in animals and patients with experimentally induced hindlimb or myocardial ischemia. To address the possible contribution of postnatal endogenous VEGF expression to collateral vessel development in ischemia tissues, we developed a mouse model of hindlimb ischemia. The femoral artery of one hindlimb was ligated and excised. Laser Doppler perfusion imaging (LDPI) was employed to document the consequent reduction in hindlimb blood flow, which typically persisted for up to 7 days. Serial in vivo examinations by LDPI disclosed that hindlimb blood flow was progressively augmented over the course of 14 days, ultimately reaching a plateau between 21 and 28 days. Morphometric analysis of capillary density performed at the same time points selected for in vivo analysis of blood flow by LDPI confirmed that the histological sequence of neovascularization corresponded temporally to blood flow recovery detected in vivo. Endothelial cell proliferation was documented by immunostaining for bromodeoxyuridine injected 24 hours before each of these time points, providing additional evidence that angiogenesis constitutes the basis for improved collateral-dependent flow in this animal model. Neovascularization was shown to develop in association with augmented expression of VEGF mRNA and protein from skeletal myocytes as well as endothelial cells in the ischemic hindlimb; that such reparative angiogenesis is indeed dependent upon VEGF up-regulation was confirmed by impaired neovascularization after administration of a neutralizing VEGF antibody. Sequential characterization of the in vivo, histological, and molecular findings in this novel animal model thus document the role of VEGF as endogenous regulator of angiogenesis in the setting of tissue ischemia. Moreover, this murine model represents a potential means for studying the effects of gene targeting on nutrient angiogenesis in vivo.

Effects of poloxamer 407 on transfection time and percutaneous adenovirus-mediated gene transfer in native and stented vessels

Reduction in transfection time and the ability to perform gene transfer in conjunction with endovascular stent implantation constitute two important challenges for percutaneous adenovirus-mediated gene transfer to vessel walls. Studies have suggested that the use of biocompatible polyol poloxamer 407 could be useful. We first evaluated the use of poloxamer 407 for percutaneous gene transfer in nonstented rabbit iliac arteries. A 200-microl mixture of Ad-RSVbetagal or Ad-CMVLuc in either phosphate-buffered saline (PBS) or 20% poloxamer was delivered. After 3 days, gene transfection was evaluated by X-Gal staining or measurement of luciferase activity. Poloxamer use resulted in a 3- to 15-fold increase in the percentage of transfected cells (X-Gal, p = 0.001) and a 16-fold increase in protein product (luciferase activity, p = 0.03), and allowed a decrease in transfection time from 30 to 5 min with minimal reduction in transfection efficiency. We then evaluated the feasibility of percutaneous gene transfer, using Ad-RSVbetagal diluted in pure PBS or 20% poloxamer, in conjunction with stent implantation. Gene delivery was performed either immediately before (pre-) or after (post-) stent implantation. When adenoviruses were diluted in PBS, gene transfer had a low efficiency (prestent, 0.3%; poststent, 0.2%; NS). With poloxamer, the efficacy was much higher (p = 0.0001) and similar "pre" (2.2%) or "post" (1.7%) stent delivery (NS).

CONCLUSIONS

(1) The use of poloxamer, rather than PBS, as a vehicle increases the efficacy of percutaneous adenovirus-mediated gene transfer and reduces transfection time; (2) gene transfer performed during stent implantation with poloxamer is feasible and achieves a significant level of gene expression. Thus percutaneous gene delivery is applicable to conventional stents and could present an attractive method by which to achieve local biological effects in a stent environment.

Constitutive expression of phVEGF165 after intramuscular gene transfer promotes collateral vessel development in patients with critical limb ischemia

BACKGROUND

Preclinical studies have indicated that angiogenic growth factors can stimulate the development of collateral arteries, a concept called "therapeutic angiogenesis." The objectives of this phase 1 clinical trial were (1) to document the safety and feasibility of intramuscular gene transfer by use of naked plasmid DNA encoding an endothelial cell mitogen and (2) to analyze potential therapeutic benefits in patients with critical limb ischemia.

METHODS AND RESULTS

Gene transfer was performed in 10 limbs of 9 patients with nonhealing ischemic ulcers (n=7/10) and/or rest pain (n=10/10) due to peripheral arterial disease. A total dose of 4000 microg of naked plasmid DNA encoding the 165-amino-acid isoform of human vascular endothelial growth factor (phVEGF165) was injected directly into the muscles of the ischemic limb. Gene expression was documented by a transient increase in serum levels of VEGF monitored by ELISA. The ankle-brachial index improved significantly (0.33+/-0.05 to 0.48+/-0.03, P=.02); newly visible collateral blood vessels were directly documented by contrast angiography in 7 limbs; and magnetic resonance angiography showed qualitative evidence of improved distal flow in 8 limbs. Ischemic ulcers healed or markedly improved in 4 of 7 limbs, including successful limb salvage in 3 patients recommended for below-knee amputation. Tissue specimens obtained from an amputee 10 weeks after gene therapy showed foci of proliferating endothelial cells by immunohistochemistry. PCR and Southern blot analyses indicated persistence of small amounts of plasmid DNA. Complications were limited to transient lower-extremity edema in 6 patients, consistent with VEGF enhancement of vascular permeability.

CONCLUSIONS

These findings may be cautiously interpreted to indicate that intramuscular injection of naked plasmid DNA achieves constitutive overexpression of VEGF sufficient to induce therapeutic angiogenesis in selected patients with critical limb ischemia.

Definition of healthy eating in the Spanish adult population: a national sample in a pan-European survey

A national survey was carried out to find out how the Spanish adult population defined 'healthy eating'. Consumers were asked to describe in their own words what 'healthy eating' means to them. The sample included 1009 Spanish subjects over 15 y of age selected by a multietapic procedure. This study belongs to the Spanish partnership in a pan-European survey about attitudes to food, nutrition and health coordinated by the Institute of European Food Studies of Dublin. The results were shown as the percentages of the sample who gave one of the five most frequently mentioned descriptions ('more vegetables', 'balanced diet', 'more fruit', 'less fat' and 'more fish') and the distribution of responses by age, sex, region, socio-economic level and education level. A multivariable logistic regression model was fitted to assess the characteristics independently related to the use of the definition 'balance and variety' for healthy eating. The majority of the Spanish people defined 'healthy eating' as a diet with 'more vegetables' as the main description. Other descriptions commonly mentioned were 'less fat', 'more fruit', 'more fish', and 'more lean meat'. A higher age was associated with a lower likelihood of mentioning the concept of balanced diet. A higher educational level was also independently and strongly related to a higher prevalence of this definition. Differences between men and women showed only borderline significance. Our results suggest the need to improve nutritional education about fiber, low fat and cholesterol. It would be interesting to develop strategies in Spain to educate people on a definition of 'healthy eating' based upon 'balance and variety'.

Immunolocalization of thrombospondin-1 in human atherosclerotic and restenotic arteries

Experimental studies have implicated a functional role for the extracellular matrix glycoprotein thrombospondin-1 (TSP-1) in vascular smooth muscle cell proliferation and migration. We therefore sought to determine if TSP-1 might represent a specific component of the fibroproliferative tissue typically associated with restenosis lesions from human coronary and peripheral arteries. Positive immunostaining for TSP-1 was limited to hypocellular plaques typical of primary atherosclerosis; in contrast, such staining was nearly absent from the loose extracellular matrix of the fibroproliferative tissue typical of restenotic lesions. Only a small fraction of vascular smooth muscle cells in either primary or restenotic lesions demonstrated a cellular staining pattern for TSP-1, which was also observed in control studies performed in cell culture and in atherosclerotic rabbit arteries examined 3 days after experimental balloon angioplasty. Double-staining for TSP-1 and proliferating cell nuclear antigen in studies of human beings disclosed that only a small portion of proliferating cell nuclear antigen-positive cells also stained for TSP-1. The observations made in this series of specimens thus indicate that TSP-1 is not a major component of the extracellular matrix of human restenotic tissues, even when such specimens demonstrate evidence of hypercellularity or ongoing cellular proliferation. Because most restenosis specimens, however, were retrieved > or =1 month after the primary intervention, a functional role for TSP-1 in smooth muscle cell proliferation or migration at the early stages of lesion development is still possible.

Treatment of acute limb ischemia by intramuscular injection of vascular endothelial growth factor gene

BACKGROUND

Ischemic skeletal muscle has been shown to be advantageous for taking up and expressing genes transferred in the form of naked plasmid DNA. Therefore, acutely ischemic skeletal muscle may represent a potential target for IM gene therapy with naked DNA. Accordingly, we investigated the impact of IM injection of plasmid DNA encoding the secreted angiogenic growth factor, vascular endothelial growth factor (VEGF), on collateral vessel development in an animal model of acute hindlimb ischemia.

METHODS AND RESULTS

After ligation of distal external iliac artery in New Zealand White rabbits, we directly injected 500 microg of phVEGF165 into the ischemic thigh muscles. At 30 days posttransfection, VEGF-transfected animals had more angiographically recognizable collateral vessels (angiographic score=0.72+/-0.06 versus 0.48+/-0.10; P<.01) as well as histologically assessed capillaries (248+/-37 versus 180+/-32/mm2, P<.01) compared to controls. Hemodynamic deficit was less severe in VEGF-transfected animals by calf systolic blood pressure ratio (0.80+/-0.09 versus 0.56+/-0.10, P<.01) and by flow to the ischemic limb measured with Doppler guidewire (resting flow=22+/-5 versus 14+/-4; P<.01; hyperemic flow=59+/-17 versus 39+/-12 mL/min; P<.05). Human VEGF mRNA was expressed in the transfected ischemic muscles as long as 14 days after gene transfer. Based on reporter plasmid expression, transfection efficiency was sixfold higher in ischemic muscles than in nonischemic control muscles.

CONCLUSIONS

These results suggest the feasibility of employing direct IM transfer of naked VEGF plasmid DNA to optimize treatment of acute limb ischemia.

Reciprocal relation between VEGF and NO in the regulation of endothelial integrity

Balloon angioplasty disrupts the protective endothelial lining of the arterial wall, rendering arteries susceptible to thrombosis and intimal thickening. We show here that vascular endothelial growth factor (VEGF), an endothelial cell mitogen, is upregulated in medial smooth muscle cells of the arterial wall in response to balloon injury. Both protein kinase C (PKC) and tyrosine kinase pp60src mediate augmented VEGF expression. In contrast, nitric oxide (NO) donors inhibit PKC-induced VEGF upregulation by interfering with binding of the transcription factor activator protein-1 (AP-1) to the VEGF promoter. Inhibition of VEGF promoter activation suggests that NO secreted by a restored endothelium functions as the negative feedback mechanism that downregulates VEGF expression to basal levels. Administration of a neutralizing VEGF antibody impaired reendothelialization following balloon injury performed in vivo. These findings establish a reciprocal relation between VEGF and NO in the endogenous regulation of endothelial integrity following arterial injury.

Perceived need to alter eating habits among representative samples of adults from all member states of the European Union

OBJECTIVE

To examine the perceived need to alter eating habits among nationally-representative samples from each member state of the European Union (EU).

DESIGN

A cross-sectional study in which quota-controlled, nationally-representative samples of approximately 1000 adults from each country completed a face-to-face interview-assisted questionnaire.

SETTING

The survey was conducted between October 1995 and February 1996 in the 15 member states of the European Union.

SUBJECTS

14,331 subjects (aged 15 y upwards) completed the questionnaire. Data were weighted by population size for each country and by sex, age and regional distribution within each member state.

RESULTS

71% of EU subjects agreed with the statement 'I do not need to make changes to the food I eat, as it is already healthy enough'. There was wide variation between the member states ranging from 47% in Finland to 87% in Italy indicating agreement. Overall there was little difference between the sexes except in Austria, Belgium, Germany, Greece and Ireland, but the proportions of subjects agreeing with the statement generally increased with advancing age and decreased with higher levels of education. The effects of demographics were not consistent across member states. A total of 49% of EU subjects agreed with the statement 'I usually do not think of the nutritional aspects of the food I eat'. Significantly more females than males disagreed with the statement in all countries except Portugal. In all member states there were widespread beliefs that people in general should decrease their consumption of savoury snacks and increase their consumption of fruit and vegetables.

CONCLUSIONS

The results of this study demonstrate that dietary advice may not be perceived as personally relevant among EU subjects. In addition important target groups for the promotion of healthy eating have been identified for example, males or subjects with low levels of education. Because of the variation in attitudes a single pan-EU healthy eating programme is unlikely to be effective for all countries or for different demographic groups.

Influences on food choice perceived to be important by nationally-representative samples of adults in the European Union

OBJECTIVE

The purpose of this baseline survey was to obtain comparable data on perceived influences on food choice from EU member countries as the starting point for EU healthy eating promotion campaigns and programmes.

DESIGN

A cross-sectional study in which quota-controlled, nationally-representative samples of approximately 1000 adults from each country completed a face-to-face interview-assisted questionnaire.

SETTING

The survey was conducted between October 1995 and February 1996 in the 15 member states of the European Union.

SUBJECTS

14331 subjects (aged 15 y upwards) completed the questionnaire. Data were weighted by population size for each country and by sex, age and regional distribution within each member state.

RESULTS

The five most important factors influencing consumers food choice were 'quality or freshness' (74%), 'price' (43%), 'taste' (38%), 'trying to eat healthy' (32%) and 'family preferences' (29%). Subjects in different categories (age, sex, education and employment status) selected different factors as having major influence on their food choice. Demographic factors seemed to have greater effects on perceived influences than culture (country): 'quality/freshness', 'price', 'trying to eat healthy', 'family preferences' seemed to be most important in women, 'taste' and 'habit' in males. Females and older and more educated subjects were more likely than other subjects to select 'trying to eat healthy' as having a major influence. 'Price' seemed most important in unemployed and retired subjects.

Definitions of 'healthy' eating: a pan-EU survey of consumer attitudes to food, nutrition and health

OBJECTIVE

To describe the perceptions of a healthy diet across Europe and to explore the socio-cultural factors that influence these perceptions.

DESIGN

A cross-sectional study in which quota-controlled, nationally-representative samples of approximately 1000 adults from each country completed a face-to-face interview-assisted questionnaire.

SETTING

The survey was conducted between October 1995 and February 1996 in the 15 member states of the European Union.

SUBJECTS

14331 subjects (aged 15 y upwards) completed the questionnaire. Data were weighted by population size for each country and by sex, age and regional distribution within each member state.

RESULTS

Responses were grouped into broad categories; overall 80% (specific country rates varied from 67-91%) of respondents mentioned either more fruit and vegetables or less fat, fatty foods, or a low fat diet, or balance and variety. The effects of age, gender and level of education were also explored: educational level appeared to have the strongest influence on perceptions of a healthy diet. Respondents who mentioned the family as a key influence on food choice, were more likely to mention eating more fruit and vegetables as part of a healthy diet. Respondents who stated that they did not have any source of information about diet were less likely to mention balance and variety or less fat or more vegetables.

CONCLUSIONS

The results of the present study suggest that many people defined healthy eating in a way which would suggest that the healthy dietary guidelines are having some impact. The results also show, however, that there may be specific groups who are missed by current national campaigns, and that any European wide campaigns to change attitudes about healthy eating need to consider the baseline perception of healthy eating reported here.

Histochemical staining following LacZ gene transfer underestimates transfection efficiency

Analysis of LacZ gene expression is conventionally inferred from blue staining that results from exposure of the transfected cells or tissue to the substrate 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal). Such histochemical staining reports not whether the gene product is present or absent, but where it is active. We investigated the hypothesis that identification of activity, as opposed to presence, of the enzyme underestimates gene expression following LacZ gene transfer. Under conditions optimized for in vitro histochemistry, up to 20% of cells stably transfected with nls-LacZ remained unstained by X-Gal. In contrast, immunostaining with a monoclonal or a polyclonal anti-beta-galactosidase (beta-Gal) antibody positively stained 99% of the cell nuclei. Following in vivo transfection of naked DNA encoding for nls-LacZ, X-Gal staining disclosed 2.7 +/- 1.7 positive nuclei per LacZ-transfected animal, or a transfection efficiency of 0.015%. In contrast, immunohistochemical staining disclosed 118 +/- 32.7 positive nuclei per transfected animal, yielding a transfection efficiency of 0.64% (p < 0.0001 versus X-Gal staining). Thus, 42.9 times more positive cells were detected by antibody than X-Gal staining. Finally, LacZ gene expression following intramuscular gene transfer with an adenoviral vector was observed in 7.6% of skeletal muscle cells assessed with X-Gal; anti-beta-Gal antibody identified 21.8% of cells as being successfully transfected (p < 0.0001). Thus, X-Gal histochemistry following gene transfer of constructs encoding LacZ may underestimate the anatomic extent of gene expression. The superior sensitivity of immunostaining suggests that anti-beta-Gal antibody represents the preferred analytical tool for light microscopic evaluation of LacZ gene transfer.

Vascular endothelial growth factor inhibits endothelial cell apoptosis induced by tumor necrosis factor-alpha: balance between growth and death signals

A series of experiments was performed to determine whether vascular endothelial growth factor (VEGF), in addition to its endothelial cell specific mitogenic activity, can also protect endothelial cells from toxin-induced programmed cell death. Apoptosis was induced in endothelial cell culture with tumor necrosis factor-alpha (TNF-alpha). Simultaneous exposure of endothelial cells to VEGF resulted in a dose dependent inhibition of apoptosis when evaluated by: (1) direct counting of cells with morphologic features of apoptosis after acridine orange staining; (2) analysis of DNA fragmentation by (a) agarose gel electrophoresis and (b) fluorescence activated cell sorting (FACS); and (3) viability assays dependent upon mitochondrial function. Induction of fibronectin and beta 3 integrin expression in endothelial cells by VEGF suggests that altered adhesion molecule expression may explain this survival effect.

Passivation of metallic stents after arterial gene transfer of phVEGF165 inhibits thrombus formation and intimal thickening

OBJECTIVES

This study sought to test the hypothesis that direct gene transfer of an endothelial cell mitogen could passivate metallic stents by accelerating endothelialization of the prosthesis.

BACKGROUND

Thrombosis and restenosis comprise the principal clinical manifestations of compromised biocompatibility of endovascular stents. Previous studies have demonstrated that endothelial recovery at sites of balloon injury is a critical determinant of consequent intimal thickening and mural thrombus. We therefore investigated the potential for an endothelial cell mitogen delivered as plasmid DNA to optimize stent biocompatibility.

METHODS

Naked plasmid DNA encoding vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF) (phVEGF165) was delivered locally using a hydrogel-coated balloon angioplasty catheter to 16 rabbit iliac arteries in which metallic stents had been placed at the site of balloon injury; the contralateral iliac artery of each rabbit was balloon injured and stented but not transfected.

RESULTS

Stent endothelialization was accelerated by phVEGF165 gene transfer (87.38 +/- 5.06% vs. 33.13 +/- 9.73% [mean +/- SEM] of the planimetered stent surface in the treated vs. contralateral limb, p = 0.005). This was associated with a significant reduction in mural thrombus (3.7 +/- 2.4% vs. 32.7 +/- 9.7%, p = 0.01) at day 7 and intimal thickening (maximal intimal area 0.61 +/- 0.09 vs. 1.44 +/- 0.12 mm2, p < 0.0001) at day 28. No benefit was observed from pCMV-luciferase in 14 similarly instrumented control rabbits.

CONCLUSIONS

These findings indicate that arterial gene transfer of naked plasmid DNA encoding for an endothelial cell mitogen may successfully passivate endovascular stents by accelerating stent endothelialization, thereby reducing in-stent thrombus and obstruction due to intimal thickening.

Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) in normal and atherosclerotic human arteries

Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is an endothelial-cell-specific mitogen; as such, its role in angiogenesis has been studied extensively. VEGF/VPF may also serve as a local, endogenous regulator of large-vessel endothelial cell integrity. Surprisingly, however, VEGF/VPF expression in normal and/or atherosclerotic vessels has not been previously characterized. Accordingly, we studied normal human arteries and veins as well as atherosclerotic and restenotic human coronary arteries for evidence of VEGF/VPF expression. VEGF/VPF was detected immunohistochemically in sections of normal human aorta, mammary artery, and saphenous vein. Moreover, VEGF/ VPF expression was identified in 32 (97%) of 33 pathological coronary arterial specimens; the extent of VEGF/VPF staining was graded as moderate to strong in 21 of the 32 (66%) positive specimens. VEGF/VPF double immunostaining and in situ hybridization demonstrated that smooth muscle cells constitute the principal cellular source of VEGF/VPF. VEGF/VPF immunostaining among primary atherosclerotic lesions localized predominantly to the extracellular matrix. In restenotic specimens, VEGF/VPF immunostaining was more prominently cellular, particularly among proliferating smooth muscle cells. Although VEGF/VPF expression was observed in areas of macrophage infiltration, double immunostaining failed to localize VEGF/VPF to macrophages in these foci; instead, double immunostaining clearly identified CD45RO-positive cells as responsible for VEGF/VPF expression in such areas. No correlation could be demonstrated between VEGF/VPF immunostaining and extent of vasa vasorum. These findings thus establish that postnatal VEGF/VPF expression is a feature of normal human arteries and veins and is often extensively expressed in arteries narrowed by atherosclerotic plaque. VEGF/VPF expression in the wall and/or plaque of medium to large vessels suggests a role for VEGF/VPF other than promoting angiogenesis. This role may involve maintenance and repair of luminal endothelium.

Histopathology of in-stent restenosis in patients with peripheral artery disease

BACKGROUND

Clinical studies have suggested that smooth muscle cell (SMC) hyperplasia is the most likely cause of in-stent restenosis. However, pathological data regarding this issue are limited. Specifically, direct evidence of proliferative activity in tissues excised from stenotic stents has not been previously reported.

METHODS AND RESULTS

Tissue specimens were retrieved by directional atherectomy from 10 patients in whom in-stent restenosis complicated percutaneous revascularization of peripheral artery disease. Analysis of cellular composition was performed quantitatively after cell-specific immunostaining. For specimens preserved in methanol (7 of 10), cellular proliferation was evaluated by use of antibodies to proliferating cell nuclear antigen (PCNA), cyclin E, and cdk2. TUNEL staining for apoptosis was performed on 8 paraformaldehyde-preserved specimens. Each of the 10 specimens contained extensive foci of hypercellularity composed predominantly of SMCs (mean+/-SEM, 59.3+/-3.0%). Evidence of ongoing proliferative activity was documented in all 7 methanol-preserved specimens: 24.6+/-2.3% of SMCs were PCNA-positive, 24.8+/-3.1% were cyclin E-positive, and 22.5+/-2.2% were cdk2-positive. Apoptotic cells were detected in all 8 specimens that had been appropriately preserved to permit DNA nick-end labeling. Macrophages and leukocytes were identified in each of the 10 specimens but accounted for a proportionately smaller number of cells (14.5+/-1.9% and 9.5+/-1.4%, respectively). Organized thrombus was observed in 6 of the 10 specimens.

CONCLUSIONS

These findings support the notion that in-stent restenosis results from SMC hyperplasia and suggest that adjunctive therapies designed to inhibit SMC proliferation may further enhance the utility of endovascular stents.

Differential expression of 92-kDa gelatinase in primary atherosclerotic versus restenotic coronary lesions

Rupture of atherosclerotic plaque resulting in intravascular thrombosis and myocardial infarction (MI), while a common sequelae of de novo atherosclerotic lesions, is an uncommon consequence of restenosis. We hypothesize that the rarity of MI associated with restenotic lesions is a result of cellular and biochemical modifications induced by the local response to mechanical injury rendering the site resistant to rupture. Clinical and angiographic features of patients presenting with symptomatic primary (n = 24) or restenotic coronary lesions (n = 12) who underwent directional atherectomy were compared. Histologic analysis and immunostaining for 92-kDa gelatinase were performed on each atherectomy specimen. There was no significant difference between the 2 groups regarding age, gender, incidence of diabetes, smoking, hypertension, hypercholesterolemia, or previous MI. Lesion length, extent, and distribution of disease and percent stenosis were not significantly different between groups. However, 8% of primary lesions were hypercellular compared with 75% of restenotic specimens (p = 0.0001). Hypercellularity in restenotic specimens was shown by adjacent section staining to be composed of smooth muscle cells. Ninety-two kDa gelatinase was expressed in 79% of primary lesions versus 0% of restenotic specimens (p = 0.0001). Thrombus was identified in 54% of primary lesions versus 22% of restenotic lesions (p <0.05). These findings suggest that, independent of clinical or angiographic influences, balloon injury induces increased lesion cellularity and reduced expression of 92-kDa gelatinase, possibly resulting in a reduced propensity for plaque rupture and thrombosis.

Differential expression of nonmuscle myosin II isoforms in human atherosclerotic plaque

Intimal proliferation and functional changes involving vascular smooth muscle cells are key events in the development of atherosclerosis, including restenosis after percutaneous transluminal angioplasty. Nonmuscle myosin (NMM) is required for cytokinesis and has been shown in cultures of vascular smooth muscle cells to undergo changes of isoform expression depending on the stage of proliferation and differentiation. The purpose of this study was to examine the differential expression of the two most recently identified nonmuscle myosin heavy chain isoform II (NMMHC-II) isoforms A and B in atherosclerotic plaque. Primary atherosclerotic and restenotic atherectomy specimens and non-atherosclerotic controls, were analyzed by Western Blot analysis, immunohistochemistry and in situ hybridization. Nonmuscle myosin heavy chain isoform IIA (NMMHC-IIA) was equally expressed in all types of tissue specimens both at the protein and mRNA levels. In contrast, NMMHC-IIB protein was found in restenotic specimens and normal artery but was at very low levels in primary atherosclerotic plaque. By in situ hybridization NMMHC-IIB mRNA levels were significantly greater in restenotic versus primary atherosclerotic lesions. NMMHC-IIB expression is associated with vascular restenosis but is downregulated in stable atherosclerotic lesions, whereas NMMHC-IIA is expressed in both. These results indicate that these new myosin isoforms have different functions and should be regarded separately with respect to smooth muscle proliferation and restenosis. They should prove to be useful molecular markers for the study of atherosclerosis and restenosis.

Estrogen-receptor-mediated inhibition of human endothelial cell apoptosis. Estradiol as a survival factor

BACKGROUND

A series of studies was performed to examine the ability of estradiol (E2) to protect endothelial cells from apoptosis.

METHODS AND RESULTS

Light and transmission electron microscopy demonstrated typical features of apoptosis in human umbilical vein endothelial cells (HUVEC) exposed to tumor necrosis factor-alpha (TNF-alpha). Northern and Western blot analyses revealed induction of message and protein for the interleukin-1 beta converting enzyme (ICE), which has been shown to mediate apoptosis induced by TNF-alpha. Immunofluorescent staining of HUVEC colocalized ICE expression to apoptotic HUVEC. Direct cell counting demonstrated a significant decrease in total endothelial cell number after 24 hours of TNF-alpha exposure and a dose-dependent reversal of the effect of TNF-alpha with E2 treatment. This protective effect was abrogated by an estrogen-receptor antagonist. Fluorescence-activated cell sorting analysis revealed 39.3% apoptosis after 24 hours of TNF-alpha exposure. Treatment with E2 resulted in a 50% decrease in apoptosis. Similarly, viability assays revealed 35 +/- 4% cell death after TNF-alpha exposure. Simultaneous treatment with E2 resulted in a dose-dependent reduction of cell death to a minimum of 18 +/- 2%. The protective effect of E2 was nullified by a specific estrogen-receptor antagonist.

CONCLUSIONS

E2 treatment resulted in a dose-dependent, receptor-mediated inhibition of TNF-alpha-induced endothelial cell apoptosis. These studies indicate that E2 may also serve a maintenance function in preventing endothelial cell death after noxious stimuli and suggest that the ICE pathway may mediate cytokine-induced apoptosis in endothelial cells. Preservation of endothelial integrity represents another mechanism that may account for the atheroprotective effect of estrogen.

Improved efficiency of arterial gene transfer by use of poloxamer 407 as a vehicle for adenoviral vectors

Improvement in the efficiency of adenovirus-mediated arterial gene transfer may augment the utility of cardiovascular gene therapy. In vitro studies suggest that poloxamer 407 enhances transfection efficiency of adenoviral vectors in vascular smooth muscle cells. The aim of the present study was to investigate whether poloxamer 407 facilitates adenovirus-mediated arterial transfection in vivo as well. Gene transfer was performed in balloon-injured rat carotid arteries using E1- adenoviral vectors diluted in either poloxamer 407 or phosphate buffered saline (PBS). Transfection efficiency was significantly higher in rats transfected using a nuclear beta-galactosidase expressing adenovector diluted in poloxamer 407 versus PBS (morphometry, 13.2 +/- 1.3% versus 4.1 +/- 0.4% transfected medial cells, P = 0.0001; chemiluminescence; 1.4 +/- 0.2 versus 0.4 +/- 0.2 mU beta-galactosidase/mg protein, P = 0.004). Moreover, in the presence of poloxamer 407, it was possible to reduce the incubation time of adenoviral vectors from 20 to 10 min without compromising transfection efficiency. Poloxamer 407 did not evoke specific tissue toxicity. Site-specificity of arterial gene transfer, assessed by PCR, was not altered by administration of poloxamer 407. These findings suggest that poloxamer 407 may be useful to improve the efficiency of adenovirus-mediated arterial gene transfer.

Temporally and spatially coordinated expression of cell cycle regulatory factors after angioplasty

Intimal hyperplasia following angioplasty results in part from the migration and proliferation of vascular smooth muscle cells (VSMCs). However, the cell cycle regulatory networks underlying injury-induced VSMC proliferation are largely unknown. In the present study, we examined the kinetics of expression and activity of cell cycle regulatory factors after angioplasty in rat and human arteries. Cell lysates were prepared from uninjured rat carotid arteries and at different time points after balloon denudation. Marked induction of the proliferating cell nuclear antigen (PCNA), the G1/S cyclin-dependent kinase (cdk2), and its regulatory subunits (cyclin E and cyclin A) occurred between 1 and 2 days after angioplasty, was sustained up to 10 days after injury, and then declined. Induction of these factors correlated with increased cdk2-, cyclin E-, and cyclin A-dependent kinase activity, indicating the assembly of functional cdk2/cyclin E and cdk2/cyclin A holoenzymes in the injured arterial wall. Immunohistochemical analysis revealed early expression of cdk2, cyclin E, and PCNA within the media of injured carotid arteries. At later time points, expression of these markers declined to basal levels in the media but was detected within the intimal lesion. Thus, VSMC proliferation after angioplasty in the rat carotid artery is associated with a temporally and spatially coordinated expression of cdk2, cyclins E and A, and PCNA. Analysis of human arteries also revealed expression of these factors in VSMCs within restenotic lesions. Thus, cdk2 and its regulatory cyclins may be suitable targets to limit human restenosis.

Impact on ventricular function and quality of life of transcatheter ablation of the atrioventricular junction in chronic atrial fibrillation with a normal ventricular response

We assessed left ventricular function and quality of life after atrioventricular junction ablation and pacemaker implant in 14 patients with chronic atrial fibrillation and normal ventricular response. A significant improvement in left ventricular ejection fraction, fractional shortening, and functional capacity were observed at follow-up, suggesting that in patients with chronic atrial fibrillation a regular heart beat may be preferable over rate control.

Direct intramuscular gene transfer of naked DNA encoding vascular endothelial growth factor augments collateral development and tissue perfusion

BACKGROUND

Striated muscle has been shown to be capable of taking up and expressing foreign genes transferred in the form of naked plasmid DNA, although typically with a low level of gene expression. In the case of genes that encode secreted proteins, however, low transfection efficiency may not preclude bio-activity of the secreted gene product. Accordingly, we investigated the hypothesis that intramuscular (IM) gene therapy with naked plasmid DNA encoding vascular endothelial growth factor (VEGF) could augment collateral development and tissue perfusion in an animal model of hindlimb ischemia.

METHODS AND RESULTS

Ten days after ischemia was induced in one rabbit hindlimb, 500 micrograms of phVEGF165, or the reporter gene LacZ, was injected IM into the ischemic hindlimb muscles. Thirty days later, angiographically recognizable collateral vessels and histologically identifiable capillaries were increased in VEGF transfectants compared with controls. This augmented vascularity improved perfusion to the ischemic limb, documented by a superior calf blood pressure ratio for phVEGF165 (0.85 +/- 0.05) versus controls (0.64 +/- 0.05, P < .01), improved blood flow in the ischemic limb (measured with an intra-arterial Doppler wire) at rest (phVEGF165 = 21.3 +/- 3.9 mL/min, control = 14.6 +/- 1.6 mL/min, P < .01) and after a vasodilator (phVEGF165 = 54.2 +/- 12.0 mL/min, control = 37.3 +/- 8.9 mL/min, P < .01) and increased microspheres in the adductor (phVEGF165 = 4.3 +/- 1.6 mL.min-1.100 g of tissue-1, control = 2.9 +/- 1.2 mL.min-1.100 g of tissue-1, P < .05) and gastrocnemius (phVEGF165 = 3.9 +/- 1.0 mL.min-1.100 g of tissue-1, control = 2.8 +/- 1.4 mL.min-1.100 g of tissue-1, P < .05) muscles of the ischemic limb.

CONCLUSIONS

Ischemic skeletal muscle represents a promising target for gene therapy with naked plasmid DNA. IM transfection of genes encoding angiogenic cytokines, particularly those that are naturally secreted by intact cells, may constitute an alternative treatment strategy for patients with extensive peripheral vascular disease in whom the use of intravascular catheter-based gene transfer is compromised and/or prohibited.

Accelerated restitution of endothelial integrity and endothelium-dependent function after phVEGF165 gene transfer

BACKGROUND

Delinquent reendothelialization (rET) has been shown to have a permissive, if not facilitatory, impact on smooth muscle cell proliferation. This inverse relation has been attributed to certain functions of the endothelium, including barrier regulation of permeability, thrombogenicity, and leukocyte adherence, as well as production of growth-inhibitory molecules. Accordingly, the present investigation was designed to test the hypothesis that an endothelial cell (EC) mitogen could serve as the basis for a novel gene therapy strategy designed to facilitate EC regeneration, reduce neointimal thickening, and promote recovery of EC dysfunction after balloon injury.

METHODS AND RESULTS

New Zealand White rabbits underwent simultaneous balloon injury and gene transfer of one femoral artery with phVEGF165, encoding the 165-amino acid isoform of vascular endothelial growth factor (VEGF), or pGSVLacZ. In each animal transfected with phVEGF165 or pGSVLacZ, the contralateral femoral artery was also subjected to balloon injury but not to gene transfer. For pGSVLacZ, rET remained incomplete at 4 weeks after transfection; in contrast, phVEGF165 produced prompt rET, which was 95% complete by 1 week. Furthermore, rET in the contralateral, balloon-injured, nontransfected limb of the VEGF group was similarly accelerated. Consequently, intimal thickening was diminished, thrombotic occlusion was less frequent, and recovery of EC-dependent vasomotor reactivity was accelerated in VEGF transfectants compared with control animals. A similar benefit was observed for the contralateral, balloon-injured, nontransfected limb.

CONCLUSIONS

Catheter-mediated, site-specific arterial gene transfer of phVEGF165 can accelerate rET at local and remote sites, leading to inhibition of neointimal thickening, reduction in thrombogenicity, and restoration of endothelium-dependent vasomotor reactivity. These findings support the notion that gene transfer encoding for an EC-specific mitogen may be useful for preventing the complications, including restenosis, of balloon angioplasty.

Radiofrequency ablation of atrial flutter and atrial tachycardias in patients with permanent indwelling catheters

The presence of chronic indwelling leads in the area targeted for RF ablation may pose a technical challenge and reduce the chance of success of the ablation. In addition, application of lesions in close proximity to pacemaker leads or other permanent catheters could affect their function. Fourteen patients referred for RF ablation of atrial flutter/fibrillation and atrial tachycardia, who had a permanent dual chamber pacemaker (10 patients), ICD (1 patient), or both (3 patients) were studied to assess the safety, efficacy, and effects of the ablative procedure on device function. Lead impedance, R and P wave amplitude, and pacing threshold of the defibrillator and pacemaker were measured before and after ablation. The procedure was successful in all patients. In one patient who underwent both atrial flutter and atrial fibrillation ablation, the atrial pacing threshold increased from 1.0 preablation to 2.0 V postablation. No P wave was detectable after ablation. In another patient, the P wave amplitude went from 4.0 to 2.0 mV postablation. In both patients the device converted to the power reset mode. No changes were observed in the remaining patients. Postablation defibrillator testing showed no malfunction. Follow-up reinterrogation of the devices revealed no alterations.

IN CONCLUSION

(1) RF ablation of atrial flutter and/or tachycardia is feasible even in patients with multiple chronic atrial and ventricular indwelling catheters; and (2) RF applications in close proximity of defibrillator and pacing catheters does not appear to alter their function unless lesions are produced in the area surrounding the distal pacing electrode.

Elevated levels of basic fibroblast growth factor in patients with limb ischemia

Basic fibroblast growth factor (bFGF), a prototypic member of a family of heparin-binding growth factors, is angiogenic both in vitro and in vivo. Increased levels and activity of bFGF have been documented in a variety of diseases, including tumors. We sought to determine whether bFGF might be similarly elevated in patients with clinical evidence of limb ischemia. Serum was obtained at the time of percutaneous revascularization from patients with symptomatic peripheral vascular disease (46 procedures were performed on 40 patients). An enzyme-linked immunoassay specific for bFGF was used (limit of detection, 1 pg/ml; range in normal subjects, 0 to 5 pg/ml). Among the 40 patients (28 men, 12 women, mean age 70 years) studied, elevated circulating bFGF (> or = 10 pg/ml) was detected in 36 samples (78%); levels ranged from 10 to 310 pg/ml (mean +/- SEM = 62 +/- 12). In 16 (89%) of 18 patients with both rest pain and nonhealing ischemic ulcers, serum bFGF levels were elevated up to 30 times normal values. In conclusion, circulating levels of bFGF are elevated in patients with vascular insufficiency and may reflect a physiologic response to limb ischemia.

Effect of subintimal resection on initial outcome and restenosis for native coronary lesions and saphenous vein graft disease treated by directional coronary atherectomy. A report from the CAVEAT I and II investigators. Coronary Angioplasty Versus Excisional Atherectomy Trial

OBJECTIVES

This study was designed to determine whether the depth of tissue resection affected either immediate outcome or subsequent restenosis in patients treated by directional coronary atherectomy (DCA) in the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) I and II studies.

BACKGROUND

The relation between the depth of tissue resection, immediate outcome and subsequent restenosis in lesions treated with DCA has been controversial.

METHODS

In CAVEAT I, 412 patients undergoing DCA had tissue samples available for analysis by the core laboratory, whereas in CAVEAT II, 113 patients had vein graft tissue specimens available.

RESULTS

Subintimal deep arterial wall resection was demonstrated in 169 patients (41%) in CAVEAT I and 40 (35%) in CAVEAT II. The depth of tissue resection did not affect initial procedural outcome in either CAVEAT I or CAVEAT II, nor did it affect subsequent restenosis rates at 6 months in native coronary lesions (CAVEAT I, 50.8% for intimal resection vs. 51.2% for subintimal resection). In patients treated with vein graft disease (CAVEAT II), restenosis rates varied; when resection was limited to the intima, a restenosis rate of 40.4% was documented, whereas in patients with subintimal resection, the restenosis rate was 57.1%. This difference was not statistically significant (p = 0.144).

CONCLUSIONS

This combined randomized series of DCA for treatment of primary native coronary artery and vein graft stenoses with quantitative coronary angiography and core laboratory pathologic assessment resolves the controversy created by previous experimental and clinical data regarding deep vessel wall resection and immediate and longer outcome. Directional atherectomy with deep arterial wall resection as practiced in these studies is safe and does not jeopardize initial success rates. More important, deep wall resection is not associated with significantly increased restenosis rates.

Hypoxia induces vascular endothelial growth factor in cultured human endothelial cells

Smooth muscle cells, macrophages, glial cells, keratinocytes, and transformed cells have been established as synthesis sites for vascular endothelial growth factor (VEGF). The modulating effects of VEGF are essentially limited to endothelial cells (ECs), the only cell type consistently shown to express VEGF receptors. VEGF has thus been considered to act exclusively via a paracrine pathway. We sought to determine whether the role of human ECs might, under selected conditions, extend beyond that of a target to involve contingency synthesis of VEGF. In both unstimulated human umbilical vein ECs (HUVECs) and human derma-derived microvascular ECs (HMECs), Northern analysis detected no VEGF transcripts. Phorbol-12-myristate 13-acetate (10(-7) M) treatment, however, induced VEGF mRNA expression in both HUVECs and HMECs, peaking at 3 and 6 h, respectively, and returning to undetectable levels by 12 h. In vitro exposure of HUVECs to a hypoxic environment (pO2 = 35 mm of mercury) for 12, 24, and 48 h and exposure of HMECs for 6, 12, 24, and 48 h induced VEGF mRNA in a time-dependent fashion. Re-exposure to normoxia (pO2 = 150 mm of mercury) for 24 h after 24 h of hypoxia returned VEGF mRNA transcripts to undetectable levels in HUVECs. Cobalt chloride and nickel chloride treatment each induced VEGF mRNA in ECs. Cycloheximide treatment further augmented expression of VEGF mRNA induced by cobalt chloride, nickel chloride, and hypoxia in HUVECs. VEGF protein production in hypoxia HUVECs was demonstrated immunohistochemically. Conditioned media from hypoxic HUVECs caused a 2-fold increase in the incorporation of tritiated thymidine. Finally, immune precipitates of anti-KDR probed with anti-Tyr(P) antibodies demonstrated evidence of receptor autophosphorylation in hypoxic but not normoxic HUVECs. These findings thus establish the potential for an autocrine pathway that may augment and/or amplify the paracrine effects of VEGF in stimulating angiogenesis.

Time course of increased cellular proliferation in collateral arteries after administration of vascular endothelial growth factor in a rabbit model of lower limb vascular insufficiency

Proliferation of vascular cells has been previously shown to contribute to spontaneous development of coronary collaterals. Recent studies from several laboratories have established that collateral artery growth in both the heart and limb can be enhanced by administration of angiogenic growth factors, or therapeutic angiogenesis. In this study, we sought (1) to define the extent and time course of endothelial cell (EC) and smooth muscle cell (SMC) proliferation accompanying spontaneous collateral development during limb ischemia and (2) to determine the extent to which proliferative activity of ECs and SMCs is augmented during therapeutic angiogenesis with vascular endothelial growth factor (VEGF), a heparin-binding EC-specific mitogen. Ten days after induction of limb ischemia by surgically excising the femoral artery of rabbits, either VEGF (500 to 1000 micrograms) or saline was administered as a bolus into the iliac artery of the ischemic limb. Cellular proliferation was evaluated by bromodeoxyuridine labeling for 24 hours at day 0 (immediately before VEGF administration) and at days 3, 5, and 7 after VEGF, EC proliferation in the midzone collaterals of VEGF-treated animals increased 2.8-fold at day 5 (P < 0.05 versus control), and returned to baseline levels by day 7. SMC proliferation in midzone collaterals also increased 2.7-fold in response to VEGF (P < 0.05). No significant increase in EC or SMC proliferation was observed in either the stem or re-entry collaterals of VEGF-treated animals compared with untreated ischemic control animals. Reduction of hemodynamic deficit in the ischemic limb measured by lower limb blood pressure was documented at day 7 after VEGF (P < 0.01 versus untreated, ischemic control). These data thus (1) establish the contribution of cellular proliferation to collateral vessel development in limb ischemia and (2) support the concept that augmented cellular proliferation contributes to the enhanced formation of collateral vessels after therapeutic angiogenesis with VEGF.

The Local and the Global: The Anthropology of Globalization and Transnationalism

This review examines current anthropological literature concerned with migration and other forms of population movement, and with the movement of information, symbols, capital, and commodities in global and transnational spaces. Special attention is given to the significance of contemporary increases in the volume and velocity of such flows for the dynamics of communities and for the identity of their members. Also examined are innovations in anthropological theory and forms of representation that are responses to such nonlocal contexts and influences.

Epidermal growth factor receptor-targeted cytotoxin inhibits neointimal hyperplasia in vivo. Results of local versus systemic administration

Smooth muscle cell accumulation is a key feature of restenosis that may be inhibited by the delivery of receptor-targeted cytotoxins. DAB389EGF is a recombinant fusion protein in which the receptor-binding domain of diphtheria toxin has been replaced by human epidermal growth factor (EGF). We investigated the effectiveness of DAB389EGF to inhibit neointimal hyperplasia in the balloon-injured rat carotid artery. Incubation of rat carotid arteries with 125I-labeled EGF revealed extensive EGF binding sites in the neointima of balloon-injured arteries. Sixty rats subsequently received either saline or DAB389EGF (total dose, 0.15 mg) delivered immediately following balloon injury either systemically, via 14-day continuous osmotic pump infusion, or locally, via 30-minute intraluminal incubation. The effect of both treatment strategies was measured 2 weeks after injury by cross-sectional morphometric analysis of intimal area, the ratio of intimal/medial area (I/M), and the percent luminal narrowing (%LN). In addition, proliferative activity was assessed by immunostaining for the presence of the proliferating cell nuclear antigen (PCNA). Compared with controls, systemic delivery of fusion toxin significantly reduced intimal area, I/M, and %LN by 40%, 40%, and 29%, respectively. However, these rats exhibited 2% weight loss, indicating mild systemic toxicity. Local, intraluminal administration of DAB389EGF yielded a more pronounced reduction in intimal area, I/M, and %LN by 74%, 79%, and 72%, respectively. This inhibitory effect was preserved at 3 weeks postinjury, and PCNA immunostaining of locally treated arteries revealed a virtual absence of proliferative activity in the neointima and media at this timepoint. In contrast to systemically treated rats, rats receiving fusion toxin locally gained weight at a rate similar to controls, indicating avoidance of systemic toxicity. We conclude that DAB389EGF is a potent inhibitor of neointimal hyperplasia in vivo and that whereas an inhibitory effect may be achieved by systemic delivery, local delivery appears to be more potent, avoids systemic toxicity, and thus represents a feasible strategy to preempt restenosis.

[An answer to an inquiry on diffuse panbronchiolitis. Now it has found its way here!]

Diffuse panbronchiolitis (DPB) is a disease characterised by chronic inflammation in the region of respiratory bronchioles. The condition has mainly been observed in Japanese patients, though isolated cases have been reported from other countries. In a review published in Läkartidningen (37/94), the question was raised of why this disease had not been seen in Scandinavia, and whether this might be the result of missed diagnosis. The diagnostic criteria were listed, and the question was posed of whether (Scandinavian) physicians existed who had encountered patients with chronic sinusitis, persistent cough and inexplicable nodular changes in lung x-rays. As a direct result of this enquiry, the present article reports what may well be the first Scandinavian patient to fulfil all the diagnostic criteria of DPB. The patient responded with improved lung function and normalised blood gases to a combined treatment regimen comprising immunosuppression (cyclophosphamide and prednisolone) and nebulised antibiotics (gentamicin).