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D Collen

Publications and source records attributed to D Collen.

At least 55 records · Page 3Linked to original sources
PubMed2001

Depletion of circulating alpha(2)-antiplasmin by intravenous plasmin or immunoneutralization reduces focal cerebral ischemic injury in the absence of arterial recanalization.

In the absence of arterial recanalization, thrombolytic agents induce a dose-related extension of focal cerebral ischemic injury (FII) in experimental animals. However, FII is smaller in mice lacking alpha(2)-antiplasmin (alpha(2)-AP), the physiologic inhibitor of plasmin, suggesting its depletion might reduce FII in the absence of reperfusion. Therefore, the effect of human plasmin (Pli), human miniplasmin (mPli), and an Fab fragment neutralizing murine alpha(2)-AP (Fab-4H9) on FII after middle cerebral artery (MCA) ligation was studied in mice and in hamsters. In BALB/c mice, the median FII after 24 hours was 28 microL (range, 20-34) (n = 10) with saline and 23 microL (range, 17-26) (n = 9) with a single bolus of 0.07 mg Pli, given after MCA ligation (P =.010), which reduced alpha(2)-AP to 44% and fibrinogen from 0.75 to 0.44 g/L. FII was 20 microL (range, 13-26) (n = 6, P =.025) with 0.2 mg mPli and was 24 microL (range, 20-27) (n = 6, P =.020) with 1.7 mg Fab-4H9. Neuronal atrophy and reduction of laminin immunoreactivity were comparably observed in the infarct area after saline and Pli. In hamsters, a single bolus injection of 1 mg Pli, after MCA ligation, depleted alpha(2)-AP and fibrinogen and reduced FII at 24 hours from 20 microL (range, 9.9-38) (n = 6) to 7.0 microL (range, 0.44-31) (n = 7, P =.032). Thus, reduction of circulating alpha(2)-AP, with a single bolus of plasmin or of a neutralizing antibody fragment, significantly reduced FII after MCA ligation in mouse and hamster models, suggesting that, provided these observations can be extrapolated to human beings, transient depletion of circulating alpha(2)-AP might reduce ischemic stroke in the absence of reperfusion.

Animals↗
PubMed2001

Deficiency of urokinase-type plasminogen activator-mediated plasmin generation impairs vascular remodeling during hypoxia-induced pulmonary hypertension in mice.

BACKGROUND: Chronic hypoxia results in the development of pulmonary hypertension and subsequent right heart failure. A role of the plasminogen system in the pathogenesis of pulmonary hypertension and pulmonary vascular remodeling has been suggested. METHODS AND RESULTS: Mice with targeted deficiency of the gene encoding tissue-type plasminogen activator (t-PA(-/-)), urokinase-type plasminogen activator (u-PA(-/-)), u-PA receptor (u-PAR(-/-)), or plasminogen (plg(-/-)) were subjected to hypoxic conditions. Hypoxia caused a significant 2.5-fold rise in right ventricular pressure in wild-type mice. Deficiency of u-PA or plasminogen prevented this increase in right ventricular pressure, t-PA(-/-) mice showed changes that were fully comparable with wild-type mice, and u-PAR(-/-) mice showed a partial response. Hypoxia induced an increase in smooth muscle cells within pulmonary arterial walls and a vascular rarefaction in the lungs of wild-type but not of u-PA(-/-) or plg(-/-) mice. Elastic lamina fragmentation, observed in hypoxic wild-type but not in u-PA or plasminogen-deficient mice, suggested that proliferation of vascular smooth muscle cells was dependent on u-PA-mediated elastic membrane degradation. Hypoxia-induced right ventricular remodeling in wild-type mice, characterized by cardiomyocyte hypertrophy and increased collagen contents, was not seen in u-PA(-/-) and plg(-/-) mice. CONCLUSIONS: Loss of the u-PA or plasminogen gene protects against the development of hypoxia-induced pulmonary hypertension and pulmonary vascular remodeling. These observations point to an essential role of u-PA-mediated plasmin generation in the adaptive response to chronic hypoxia and the occurrence of hypoxic pulmonary vascular disease.

Animals↗
PubMed2001

Enzyme-linked immunosorbent assay for the specific detection of angiostatin-like plasminogen moieties in biological samples.

An enzyme-linked immunosorbent assay (ELISA) was developed for the specific detection of human angiostatin-like plasminogen moieties (comprising kringles 1-4) in biological samples. The assay involves prior removal of all other plasminogen moieties by immunoadsorption of diluted samples (to about 10 ng/ml plasminogen) with a mixture of insolubilized MA-42B12 (directed against kringle 5) and MA-31E9 (directed against the proteinase domain). The recovery of angiostatin during this procedure is > or = 95%. Subsequently, angiostatin-like fragments are detected in an ELISA, based on two monoclonal antibodies reacting with nonoverlapping epitopes in the kringle 1-3 domain: MA-36E6 for capture and MA-34D3 for tagging. The assay has a lower detection limit of about 0.1 ng/ml and is performed with intra- and interassay coefficient of variation of 2.4% and 15%. In tumor fluids obtained from cancer patients (n = 10), angiostatin levels ranged between 0.24 and 6.7 microg/ml (1.62+/-0.60 microg/ml; mean+/-S.E.M.) The identity of angiostatin was confirmed by immunoblotting using specific monoclonal antibodies. A weak correlation (r = .66) was observed with the total plasminogen concentration in these samples. This ELISA thus appears suitable for the specific quantitation of angiostatin-like plasminogen moieties in biological samples, and may be useful to study its (patho)physiological relevance.

Angiostatins↗
PubMed2001

Matrix metalloproteinase deficiencies do not impair cell-associated fibrinolytic activity.

The matrix metalloproteinase (MMP) and fibrinolytic (plasminogen/plasmin) systems cooperate in many (patho)physiological processes requiring extracellular proteolysis. The effect of MMP-3 (stromelysin-1), MMP-7 (matrilysin), MMP-9 (gelatinase B) or MMP-12 (metalloelastase) on cellular fibrinolytic activity was studied with the use of smooth muscle cells (SMC) and fibroblasts derived from mice with specific inactivation of these genes. Activation of cell-bound plasminogen by two-chain urokinase-type plasminogen activator (tcu-PA) was not significantly different with SMC or fibroblasts from the gene-deficient mice (78% to 140% of wild-type). For all cell types, very limited conversion of plasminogen to angiostatin-like kringle-containing fragments was observed (< 3% of the total cell-bound plasminogen). Activation of plasminogen in solution by cell-associated tcu-PA was also comparable for SMC or fibroblasts of the different genotypes (54% to 160% of wild-type). In vitro SMC migration on scrape wounded collagen-coated surfaces was comparable for wild-type, MMP-7(-/-), MMP-9(-/-) and MMP-12(-/-) SMC, but was significantly reduced for MMP-3(-/-) SMC (P < .005 vs. wild-type). Serum-free conditioned medium of MMP-3(-/-) and MMP-7(-/-) SMC or fibroblasts induced similar lysis of fibrin films as wild-type cells. These findings indicate that several interactions that have been described between these MMPs and the plasminogen/plasmin system in a purified system do not significantly affect plasmin-mediated cellular fibrinolytic activity under cell culture conditions.

Animals↗
PubMed2001

The plasminogen activator inhibitor PAI-1 controls in vivo tumor vascularization by interaction with proteases, not vitronectin. Implications for antiangiogenic strategies.

The plasminogen (Plg)/plasminogen activator (PA) system plays a key role in cancer progression, presumably via mediating extracellular matrix degradation and tumor cell migration. Consequently, urokinase-type PA (uPA)/plasmin antagonists are currently being developed for suppression of tumor growth and angiogenesis. Paradoxically, however, high levels of PA inhibitor 1 (PAI-1) are predictive of a poor prognosis for survival of patients with cancer. We demonstrated previously that PAI-1 promoted tumor angiogenesis, but by an unresolved mechanism. We anticipated that PAI-1 facilitated endothelial cell migration via its known interaction with vitronectin (VN) and integrins. However, using adenoviral gene transfer of PAI-1 mutants, we observed that PAI-1 promoted tumor angiogenesis, not by interacting with VN, but rather by inhibiting proteolytic activity, suggesting that excessive plasmin proteolysis prevents assembly of tumor vessels. Single deficiency of uPA, tissue-type PA (tPA), uPA receptor, or VN, as well as combined deficiencies of uPA and tPA did not impair tumor angiogenesis, whereas lack of Plg reduced it. Overall, these data indicate that plasmin proteolysis, even though essential, must be tightly controlled during tumor angiogenesis, probably to allow vessel stabilization and maturation. These data provide insights into the clinical paradox whereby PAI-1 promotes tumor progression and warrant against the uncontrolled use of uPA/plasmin antagonists as tumor angiogenesis inhibitors.

Angiogenesis Inhibitors↗
PubMed2001

Molecular mechanisms of blood vessel growth.

The basic molecular mechanisms governing how endothelial cells, periendothelial cells and matrix molecules interact with each other and with numerous growth factors and receptors, to form blood vessels have been presented. The many insights gained from this basic knowledge are being extended to further understand pathological angiogenesis associated with disorders such as arterial stenosis, myocardial ischemia, atherosclerosis, allograft transplant stenosis. wound healing and tissue repair. As a result, novel angiogenic and anti-angiogenic molecules are rapid-ly entering the clinic, with the promise of relief from a host of medical disorders.

Animals↗
PubMed2001

Active genes in junk DNA? Characterization of DUX genes embedded within 3.3 kb repeated elements.

The human genome contains hundreds of repeats of the 3.3 kb family in regions associated with heterochromatin. We have previously isolated a 3.3 kb-like cDNA encoding a double homeodomain protein (DUX1). Demonstration that the protein was expressed in human rhabdomyosarcoma TE671 cells, and characterization of a homologous promoter suggested that functional DUX genes might be present in 3.3 kb elements. In the present study, we describe two nearly identical 3.3 kb/DUX genes derived from PAC 137F16 (DUX3), and TE671 genomic DNA (DUX5), both mapping to all the acrocentric chromosomes. Their promoters harbor a GC and a TATAA box, and the open reading frame of the intronless structural part encodes two DUX proteins differing by alternative translation initiation. The shorter protein of the DUX5 gene is identical to DUX1. Using a protein truncation test, we could show that these two proteins are encoded by total RNA, but not by poly (A)(+) RNA, from different human tissues and cell lines. Our results indicate that active genes of unusual structure are present in chromosome regions characterized by large amounts of heterochromatic repetitive DNA.

Animals↗
PubMed2001

Soluble guanylate cyclase alpha(1) and beta(1) gene transfer increases NO responsiveness and reduces neointima formation after balloon injury in rats via antiproliferative and antimigratory effects.

In vascular smooth muscle cells, NO stimulates the synthesis of cGMP by soluble guanylate cyclase (sGC), a heterodimer composed of alpha(1) and beta(1) subunits. NO/cGMP signal transduction affects multiple cell functions that contribute to neointima formation after vascular injury. Balloon-induced vascular injury was found to decrease sGC subunit expression and enzyme activity in rat carotid arteries. The effect of restoring sGC enzyme activity on neointima formation was investigated using recombinant adenoviruses specifying sGC alpha(1) and beta(1) subunits (Adalpha1 and Adbeta1). Coinfection of cultured rat aortic smooth muscle cells with Adalpha1 and Adbeta1 increased NO-stimulated intracellular cGMP levels 60-fold and decreased DNA synthesis and migration by 16% and 48%, respectively. Immunoreactivity for alpha(1) and beta(1) subunits colocalized in carotid arteries infected with Adalpha1 and Adbeta1. Molsidomine-stimulated carotid tissue cGMP levels were greater after coinfection with Adalpha1 and Adbeta1 than after infection with a control virus, AdRR5 (0.53+/-0.09 pmol/mg protein, mean+/-SEM, versus 0.23+/-0.09, P<0.05). Mean intima/media ratio, 2 weeks after balloon injury and twice-daily administration of 5 mg/kg molsidomine, was less in rats coinfected with Adalpha1 and Adss1 than in rats infected with AdRR5 or in uninfected rats (0.36+/-0.11 versus 0. 81+/-0.13 and 0.75+/-0.25, respectively, P<0.05). Thus, Adalpha1 and Adbeta1 gene transfer to balloon-injured rat carotid arteries increases NO responsiveness and attenuates neointima formation via a direct antiproliferative and antimigratory effect on vascular smooth muscle cells.

Angioplasty, Balloon↗
PubMed2001

Deficiency or inhibition of Gas6 causes platelet dysfunction and protects mice against thrombosis.

The growth arrest-specific gene 6 product (Gas6) is a secreted protein related to the anticoagulant protein S but its role in hemostasis is unknown. Here we show that inactivation of the Gas6 gene prevented venous and arterial thrombosis in mice, and protected against fatal collagen/epinephrine-induced thrombo embolism. Gas6-/- mice did not, however, suffer spontaneous bleeding and had normal bleeding after tail clipping. In addition, we found that Gas6 antibodies inhibited platelet aggregation in vitro and protected mice against fatal thrombo embolism without causing bleeding in vivo. Gas6 amplified platelet aggregation and secretion in response to known agonists. Platelet dysfunction in Gas6-/- mice resembled that of patients with platelet signaling transduction defects. Thus, Gas6 is a platelet-response amplifier that plays a significant role in thrombosis. These findings warrant further evaluation of the possible therapeutic use of Gas6 inhibition for prevention of thrombosis.

Animals↗
PubMed2001

Synergism between vascular endothelial growth factor and placental growth factor contributes to angiogenesis and plasma extravasation in pathological conditions.

Vascular endothelial growth factor (VEGF) stimulates angiogenesis by activating VEGF receptor-2 (VEGFR-2). The role of its homolog, placental growth factor (PlGF), remains unknown. Both VEGF and PlGF bind to VEGF receptor-1 (VEGFR-1), but it is unknown whether VEGFR-1, which exists as a soluble or a membrane-bound type, is an inert decoy or a signaling receptor for PlGF during angiogenesis. Here, we report that embryonic angiogenesis in mice was not affected by deficiency of PlGF (Pgf-/-). VEGF-B, another ligand of VEGFR-1, did not rescue development in Pgf-/- mice. However, loss of PlGF impaired angiogenesis, plasma extravasation and collateral growth during ischemia, inflammation, wound healing and cancer. Transplantation of wild-type bone marrow rescued the impaired angiogenesis and collateral growth in Pgf-/- mice, indicating that PlGF might have contributed to vessel growth in the adult by mobilizing bone-marrow-derived cells. The synergism between PlGF and VEGF was specific, as PlGF deficiency impaired the response to VEGF, but not to bFGF or histamine. VEGFR-1 was activated by PlGF, given that anti-VEGFR-1 antibodies and a Src-kinase inhibitor blocked the endothelial response to PlGF or VEGF/PlGF. By upregulating PlGF and the signaling subtype of VEGFR-1, endothelial cells amplify their responsiveness to VEGF during the 'angiogenic switch' in many pathological disorders.

Animals↗
PubMed2001

Deletion of the hypoxia-response element in the vascular endothelial growth factor promoter causes motor neuron degeneration.

Hypoxia stimulates angiogenesis through the binding of hypoxia-inducible factors to the hypoxia-response element in the vascular endothelial growth factor (Vegf) promotor. Here, we report that deletion of the hypoxia-response element in the Vegf promotor reduced hypoxic Vegf expression in the spinal cord and caused adult-onset progressive motor neuron degeneration, reminiscent of amyotrophic lateral sclerosis. The neurodegeneration seemed to be due to reduced neural vascular perfusion. In addition, Vegf165 promoted survival of motor neurons during hypoxia through binding to Vegf receptor 2 and neuropilin 1. Acute ischemia is known to cause nonselective neuronal death. Our results indicate that chronic vascular insufficiency and, possibly, insufficient Vegf-dependent neuroprotection lead to the select degeneration of motor neurons.

Amyotrophic Lateral Sclerosis↗
PubMed2001

Abrupt rate accelerations or premature beats cause life-threatening arrhythmias in mice with long-QT3 syndrome.

Deletion of amino-acid residues 1505-1507 (KPQ) in the cardiac SCN5A Na(+) channel causes autosomal dominant prolongation of the electrocardiographic QT interval (long-QT syndrome type 3 or LQT3). Excessive prolongation of the action potential at low heart rates predisposes individuals with LQT3 to fatal arrhythmias, typically at rest or during sleep. Here we report that mice heterozygous for a knock-in KPQ-deletion (SCN5A(Delta/+)) show the essential LQT3 features and spontaneously develop life-threatening polymorphous ventricular arrhythmias. Unexpectedly, sudden accelerations in heart rate or premature beats caused lengthening of the action potential with early afterdepolarization and triggered arrhythmias in Scn5a(Delta/+) mice. Adrenergic agonists normalized the response to rate acceleration in vitro and suppressed arrhythmias upon premature stimulation in vivo. These results show the possible risk of sudden heart-rate accelerations. The Scn5a(Delta/+) mouse with its predisposition for pacing-induced arrhythmia might be useful for the development of new treatments for the LQT3 syndrome.

Adrenergic beta-Agonists↗
PubMed2001

Sustained expression of human apo A-I following adenoviral gene transfer in mice.

Elevation of HDL cholesterol, following adenoviral apolipoprotein A-I (apo A-I) gene transfer, may delay or revert ischemic cardiovascular disease, provided transgene expression is persistent. The choice of promoter may have significant impact on persistence of transgene expression. Human apo A-I expression was compared after adenoviral gene transfer with a cytomegalovirus promoter (CMV) driven construct (AdCMV/A-I.gA-I) and with a construct (AdA-I.gA-I.4xapoE) containing the endogenous 256 bp apo A-I promoter (A-I), the genomic human apo A-I DNA (gA-I) and 4 human apo E enhancers (4xapoE) in three different mouse strains: C57BL/6, Balb/c and Fvb. After gene transfer with 5 x 10(8) p.f.u. of AdCMV/A-I.gA-I, human apo A-I expression was observed for 35 days in C57BL/6 mice, but declined below 1 mg/dl within 14 days both in Balb/c and Fvb mice, due to a strong humoral immune response against human apo A-I. In contrast, after transfer with AdA-I.gA-I.4xapoE, human apo A-I expression persisted for 6 months in all three strains and no antibodies against human apo A-I occurred in Fvb or Balb/c mice. Human apo A-I transgene DNA level 35 days after transfer with AdA-I.gA-I.4xapoE was 4.6- to 5.5-fold higher than with AdCMV/A-I.gA-I. CMV promoter attenuation occurred in all three strains, but promoter attenuation was not observed in any strain after transfer with AdA-I.gA-I.4xapoE. In conclusion, gene transfer with AdA-I.gA-I.4xapoE is associated with absence of an immune response against human apo A-I, improved transgene DNA persistence and absence of promoter shut-off, resulting in human apo A-I expression for up to 6 months in three different mouse strains. Possibly, the absence of human apo A-I expression in antigen-presenting cells with the liver-specific apo A-I promoter containing construct abrogated the immune response against human apo A-I in Balb/c and Fvb mice.

Adenoviridae↗
PubMed2001

Critical role of glutamic acid 202 in the enzymatic activity of stromelysin-1 (MMP-3).

To test the hypothesis that Glu202, adjacent to the His201 residue that participates in the coordination of Zn(2+) in matrix metalloproteinase-3 (MMP-3 or stromelysin-1), plays a role in its enzymatic activity it was substituted with Ala, Lys or Asp by site-specific mutagenesis. Wild-type proMMP-3, proMMP-3(E202A), proMMP-3(E202K) and proMMP-3(E202D) were expressed in Escherichia coli and purified to apparent homogeneity. Whereas 33-kDa wild-type proMMP-3 (consisting of the propeptide and catalytic domains) was quantitatively converted to 24-kDa active MMP-3 by treatment with p-aminophenyl-mercuric acetate (APMA), proMMP-3(E202A) and proMMP-3 (E202K) were fully resistant to APMA and proMMP-3 (E202D) was quantitatively converted into a 14-kDa species. In contrast, treatment with plasmin quantitatively converted the wild-type and the three mutant proMMP-3 moieties into the corresponding 24-kDa MMP-3 moieties. Biospecific interaction analysis revealed comparable affinity for binding to plasminogen of wild-type and mutant proMMP-3 (K(a) of 2.6-6.3 x 10(6) M(-1)) or MMP-3 (K(a) of 33-58 x 10(6) M(-1)) moieties. The affinity for binding to single-chain urokinase-type plasminogen activator (scu-PA) was also similar for wild-type and mutant proMMP-3 (K(a) of 5.0-6.9 x 10(6) M(-1)) or MMP-3 (K(a) of 37-72 x 10(6) M(-1)) moieties. However, MMP-3(E202A) and MMP-3(E202K) did not hydrolyze plasminogen whereas MMP-3(E202D) showed an activity of 20--30% of wild-type MMP-3. All three mutants were inactive towards scu-PA under conditions where this was quantitatively cleaved by wild-type MMP-3. Furthermore, MMP-3(E202A) and MMP-3(E202K) were inactive toward a fluorogenic substrate and MMP-3 (E202D) displayed about 15% of the activity of wild-type MMP-3. Taken together, these data suggest that Glu202 plays a crucial role in the enzymatic activity of MMP-3.

Alanine↗
PubMed2001

Circulating oxidized LDL is a useful marker for identifying patients with coronary artery disease.

Our aim was to determine the usefulness of circulating oxidized low density lipoprotein (LDL) in the identification of patients with coronary artery disease (CAD). A total of 304 subjects were studied: 178 patients with angiographically proven CAD and 126 age-matched subjects without clinical evidence of cardiovascular disease. The Global Risk Assessment Score (GRAS) was calculated on the basis of age, total and high density lipoprotein cholesterol, blood pressure, diabetes mellitus, and smoking. Levels of circulating oxidized LDL were measured in a monoclonal antibody 4E6-based competition ELISA. Compared with control subjects, CAD patients had higher levels of circulating oxidized LDL (P<0.001) and a higher GRAS (P<0.001). The sensitivity for CAD was 76% for circulating oxidized LDL (55% for men and 81% for women) compared with 20% (24% for men and 12% for women) for GRAS, with a specificity of 90%. Logistic regression analysis revealed that the predictive value of oxidized LDL was additive to that of GRAS (P<0.001). Ninety-four percent of the subjects with high (exceeding the 90th percentile of distribution in control subjects) circulating oxidized LDL and high GRAS had CAD (94% of the men and 100% of the women). Thus, circulating oxidized LDL is a sensitive marker of CAD. Addition of oxidized LDL to the established risk factors may improve cardiovascular risk prediction.

Aged↗
PubMed2001

Persistence of atherosclerotic plaque but reduced aneurysm formation in mice with stromelysin-1 (MMP-3) gene inactivation.

To investigate a potential role for stromelysin-1 (MMP-3) in the development and progression of atherosclerotic lesions and aneurysm formation, mice with a deficiency of apolipoprotein E (ApoE(-/-):MMP-3(+/+))) or with a combined deficiency of apoE and MMP-3 (ApoE(-/-):MMP-3(-/-)) were kept on a cholesterol-rich diet for 30 weeks. Atherosclerotic lesions throughout the thoracic aorta were significantly larger in ApoE(-/-):MMP-3(-/-) than in ApoE(-/-):MMP-3(+/+) mice (P<0.05) and contained more fibrillar collagen (P<0.01). Aneurysms in the thoracic and abdominal aortas were less frequent in ApoE(-/-):MMP-3(-/-) than in ApoE(-/-):MMP-3(+/+) mice (8.5+/-1.7% vs 14+/-2.1% of sections, mean+/-SD, P<0.01). Immunocytochemistry revealed enhanced accumulation of macrophages in atherosclerotic lesions of ApoE(-/-):MMP-3(+/+) mice (P<0.01) and expression of urokinase-type plasminogen activator (u-PA) and MMP-3 colocalizing with macrophages. Zymography confirmed the presence of u-PA and MMP-3 activity in extracts of atherosclerotic aortas. These data suggest that plasmin, generated by macrophage-secreted u-PA, activates pro-MMP-3 produced by accumulated macrophages. MMP-3 activity may then contribute to a reduction of plaque size, possibly by degradation of matrix components, and promote aneurysm formation by degradation of the elastica lamina.

Aneurysm↗
PubMed2001

L-arginine administration reduces neointima formation after stent injury in rats by a nitric oxide-mediated mechanism.

The clinical outcome of vascular stenting is limited by in-stent stenosis. Increased nitric oxide (NO)/cGMP signaling by L-arginine (L-Arg) supplementation, the substrate for NO synthase (NOS), or NOS gene transfer may reduce in-stent neointima formation. After stenting, vascular cell proliferation in rat carotid arteries, as measured by 5'-bromodeoxyuridine (5'-BrdU) incorporation, indicated 15+/-8%, 28+/-5%, and 33+/-7% 5'-BrdU-positive vascular cells at 4, 7, and 14 days, respectively. Reporter beta-galactosidase gene transfer efficacy was evidenced by 30% beta-galactosidase-expressing medial smooth muscle cells at 14 days. The intima-to-media ratio (I/M) progressively increased to 2.32+/-0.24 at 14 days. To target in-stent neointima formation, animals were infected with adenoviral vectors (4x10(10) plaque-forming units per mL) expressing NOS2 (AdNOS2) or no transgene (AdRR5), or they received daily doses of L-Arg (500 mg. kg(-1). (d-1) IP). The neointima at 14 days was smaller in L-Arg-treated than in untreated rats (I/M 1.25+/-0.35 vs 2.32+/-0.24, P<0.05, n=7 each) or in AdRR5- and AdNOS2-infected rats (I/M 2.57+/-0.43, n=7 and 1.82+/-0.75, n=8, respectively; P<0.05 for both). The effect of L-Arg was abolished by simultaneous administration of N(G)-nitro L-arginine methyl ester, an NOS inhibitor (2.03+/-0.39, P<0.05, vs L-Arg). Inflammation was markedly less in L-Arg- and AdNOS2-treated than in AdRR5-infected rats. Supplemental L-Arg reduces neointima formation after stenting by way of an NOS-dependent mechanism and may be a valuable strategy to target in-stent stenosis.

Adenoviridae↗