Biomedical subjects

D D Heistad

Publications and source records attributed to D D Heistad.

At least 19 recordsLinked to original sources

PubMed2002

Adenovirus-mediated overexpression of extracellular superoxide dismutase improves endothelial dysfunction in a rat model of hypertension.

Gene transfer may be appropriate for therapeutic protocols targeted at the vascular endothelium. Endothelial dysfunction is the principal phenotype associated with atherosclerosis and hypertension. Oxidative stress has been implicated in the development of endothelial dysfunction. We have explored the ability of overexpressing anti-oxidant genes (superoxide dismutases; SODs) in vitro and in vivo to assess their potential for reversing endothelial dysfunction in a rat model, the stroke-prone spontaneously hypertensive rat (SHRSP). Western blotting and immunofluorescence assays in vitro showed efficient overexpression of MnSOD and ECSOD with respect to localisation to the mitochondria and extracellular surface, respectively. Transgene functional activity was quantified with SOD activity assays. MnSOD and ECSOD overexpression in intact SHRSP vessels in vivo led to endothelial and adventitial overexpression. Pharmacological assessment of transduced vessels following in vivo delivery by basal NO availability quantification demonstrated that the "null" adenovirus and MnSOD adenovirus did not significantly increase NO availability. However, AdECSOD-treated carotid arteries showed a significant increase in NO availability (1.91 +/- 0.04 versus 0.75 +/- 0.08 g/g, n = 6, P = 0.029). In summary, efficient overexpression of ECSOD, but not MnSOD in vivo, results in improved endothelial function in a rat model of hypertension and has important implications for the development of endothelial-based vascular gene therapy.

Adenoviridae↗

PubMed2002

Gene transfer of inducible nitric oxide synthase impairs relaxation in human and rabbit cerebral arteries.

BACKGROUND AND PURPOSE: These studies evaluated whether gene transfer of inducible nitric oxide synthase (iNOS) is a sufficient stimulus to produce vascular dysfunction in cerebral arteries. METHODS: Intracranial (pial) arteries were dissected from human brain tissue obtained during elective surgery. Isolated human arteries were incubated in vitro with adenovirus containing iNOS (AdiNOS) or a nonexpressive transgene (control, AdBglII) (500 micro L, 3x10(9) plaque-forming units per milliliter), and vascular function was examined 24 hours later. In anesthetized rabbits, AdiNOS or AdBglII (300 microL 1x10(10)) was injected into the cisterna magna. Three days later, the basilar artery was removed, and reactivity was examined ex vivo. RESULTS: In submaximally precontracted vessels, we observed impairment of NO-dependent relaxation in human cerebral arteries after gene transfer of iNOS. Maximum relaxation to bradykinin (1 micromol/L, an endothelium-dependent agonist) was 77+/-11% (mean+/-SE) after AdBglII and 31+/-22% (P<0.05) after AdiNOS. After AdiNOS, responses to nitroprusside (an endothelium-independent NO donor) also were impaired. Responses to both nitroprusside and bradykinin were improved by aminoguanidine (300 micromol/L), an inhibitor of iNOS. AdiNOS produced no change in vasoconstrictor responses to U46619. In basilar arteries from rabbits examined in vitro after gene transfer in vivo, responses to histamine, serotonin, and nitroprusside all were similar after AdiNOS or AdBglII. In contrast, relaxation to acetylcholine was significantly depressed after AdiNOS. Maximum relaxation to acetylcholine (10 micromol/L) was 90+/-3% after AdBglII and 68+/-5% (P<0.05) after AdiNOS. Relaxation of arteries after AdiNOS was improved by aminoguanidine. CONCLUSIONS: These studies suggest that expression of iNOS may impair NO-dependent relaxation in both human and rabbit cerebral arteries.

Animals↗

PubMed2001

Endothelial dysfunction and elevation of S-adenosylhomocysteine in cystathionine beta-synthase-deficient mice.

Hyperhomocysteinemia is associated with increased risk for cardiovascular events, but it is not certain whether it is a mediator of vascular dysfunction or a marker for another risk factor. Homocysteine levels are regulated by folate bioavailability and also by the methyl donor S-adenosylmethionine (SAM) and its metabolite S-adenosylhomocysteine (SAH). We tested the hypotheses that endothelial dysfunction occurs in hyperhomocysteinemic mice in the absence of folate deficiency and that levels of SAM and SAH are altered in mice with dysfunction. Heterozygous cystathionine beta-synthase-deficient (CBS(+/-)) and wild-type (CBS(+/+)) mice were fed a folate-replete, methionine-enriched diet. Plasma levels of total homocysteine were elevated in CBS(+/-) mice compared with CBS(+/+) mice after 7 weeks (27.1+/-5.2 versus 8.8+/-1.1 micromol/L; P<0.001) and 15 weeks (23.9+/-3.0 versus 13.0+/-2.3 micromol/L; P<0.01). After 15 weeks, but not 7 weeks, relaxation of aortic rings to acetylcholine was selectively impaired by 35% (P<0.05) and thrombomodulin anticoagulant activity was decreased by 20% (P<0.05) in CBS(+/-) mice. Plasma levels of folate did not differ between groups. Levels of SAH were elevated approximately 2-fold in liver and brain of CBS(+/-) mice, and correlations were observed between plasma total homocysteine and SAH in liver (r=0.54; P<0.001) and brain (r=0.67; P<0.001). These results indicate that endothelial dysfunction occurs in hyperhomocysteinemic mice even in the absence of folate deficiency. Endothelial dysfunction in CBS(+/-) mice was associated with increased tissue levels of SAH, which suggests that altered SAM-dependent methylation may contribute to vascular dysfunction in hyperhomocysteinemia.

Animals↗

PubMed2001

Supplementation of atherogenic diet with B vitamins does not prevent atherosclerosis or vascular dysfunction in monkeys.

BACKGROUND: Hyperhomocysteinemia is associated with increased risk of atherosclerotic and thrombotic vascular disease. In many patients, hyperhomocysteinemia can be treated or prevented by dietary supplementation with B vitamins, but the clinical benefit of B vitamins for the prevention of vascular disease has not been proven. METHODS AND RESULTS: Using an atherogenic diet that produces both hyperhomocysteinemia and hypercholesterolemia, we tested the hypothesis that dietary supplementation with B vitamins (folic acid, vitamin B(12), and vitamin B(6)) would prevent hyperhomocysteinemia, vascular dysfunction, and atherosclerotic lesions in monkeys. After 17 months, plasma total homocysteine increased from 3.6+/-0.3 to 11.8+/-1.7 micromol/L in monkeys fed an unsupplemented atherogenic diet (P<0.01) but did not increase in monkeys fed an atherogenic diet supplemented with B vitamins (3.8+/-0.3 micromol/L). Serum cholesterol increased from 122+/-7 to 550+/-59 mg/dL in the unsupplemented group (P<0.001) and from 118+/-5 to 492+/-55 mg/dL in the supplemented group (P<0.001). Responses to endothelium-dependent vasodilators, both in resistance vessels in vivo and in the carotid artery ex vivo, were impaired to a similar extent in groups that did and did not receive vitamin supplements. Anticoagulant responses to the infusion of thrombin were also impaired to a similar extent in both groups. Vitamin supplementation failed to prevent intimal thickening in the carotid or iliac arteries. CONCLUSIONS: These findings demonstrate that supplementation with B vitamins prevents hyperhomocysteinemia but is not sufficient to prevent the development of vascular dysfunction or atherosclerotic lesions in monkeys with marked hypercholesterolemia, even in the absence of preexisting atherosclerosis.

Animals↗

PubMed2001

The future of gene therapy for stroke.

New diagnostic and treatment strategies are being developed for stroke. Gene therapy has several potential advantages over classical pharmacologic therapy. Direct administration of DNA into the brain offers the advantage of producing high concentrations of therapeutic agents in a relatively localized environment. Gene transfer also provides longer duration of effect than traditional drug therapy. Recent studies indicate that gene transfer can produce functional proteins in brain parenchyma and cerebral blood vessels after stroke. In animal models, gene transfer may reduce effects of cerebral ischemia or subarachnoid hemorrhage. This review summarizes some current methods of gene transfer to the brain and recent progress that may lead to gene therapy for stroke.

Forecasting↗

PubMed2001

Gene transfer to blood vessels: a research tool and potential therapy.

Gene transfer to blood vessels is remarkably effective in altering vasomotor function, and has proven to be a useful tool for studying vascular biology. Gene therapy for cardiovascular diseases is an attractive new approach, which will be used initially for diseases in which pharmacologic approaches are not effective. Preliminary data suggest that two possible targets for gene therapy are prevention of cerebral vasospasm after subarachnoid hemorrhage and treatment of pulmonary hypertension. Perhaps, as better vectors are developed, common clinical problems such as hypertension and hypercholesterolemia also may become targets for gene therapy.

Animals↗

PubMed2001

What's new in the cerebral microcirculation? Landis Award lecture.

The first part of this paper focuses on unusual aspects of the cerebral circulation. Cerebral vessels have less smooth muscle and adventitia than other vessels, and the endothelial blood-brain barrier is unique. Because the wall of the arteries is thin, one might expect that the vessels are especially vulnerable to rupture. Pressure in intracranial arteries, however, is lower than in other arteries, because resistance of larger cerebral arteries is remarkably high. The low pressure in cerebral arteries presumably protects against rupture of the vessels. The second part of the paper summarizes some new insights into regulation of cerebral circulation. One concept is that "breakthrough" of autoregulation, with dilatation of cerebral vessels at high levels of pressure, is an active process, rather than a passive phenomenon. This conclusion is based on the finding that inhibitors of calcium-dependent potassium channels greatly attenuate the cerebral vasodilator response during acute hypertension. The third part of the paper focuses on effects of gene transfer to cerebral blood vessels. Gene transfer to intracranial and extracranial vessels is feasible and vasomotor function can be altered. Gene transfer has proven to be useful to study vascular biology, and we are optimistic that the approach will ultimately lead to gene therapy.

Animals↗

PubMed2001

Cationic polymer and lipids augment adenovirus-mediated gene transfer to cerebral arteries in vivo.

Adenovirus-mediated gene transfer to blood vessels is relatively inefficient because binding of adenovirus to vessels is limited. The authors have reported that incorporation of cationic polymer and lipids with adenovirus augments gene transfer to blood vessels ex vivo. In this study, the authors determined whether complexes of adenovirus and cations improve efficiency of gene transfer in vivo. Poly-L-lysine, lipofectamine, or lipofectin was complexed with adenovirus encoding beta-galactosidase. Optimum ratios of the cations per adenovirus were determined by gene transfer to fibroblasts. After injection of the adenovirus into the cisterna magna of anesthetized rabbits, transgene activity was greater in the adventitia of intracranial arteries and meninges after injection of the complexes than adenovirus alone. Thirty minutes after application of adenovirus with the cations, binding of adenovirus to fibroblast cells in vitro or the basilar artery in vivo (by Southern blot analysis) was augmented, which suggests that enhanced binding of virus contributes to augmentation of transgene expression. Thus, cationic polymer and lipids improve transgene expression in intracranial arteries, primarily in the adventitia, after adenovirus-mediated gene transfer in vivo. This strategy may be applicable to studies of gene transfer and eventually for gene therapy.

3T3 Cells↗

PubMed2001

Arachidonate dilates basilar artery by lipoxygenase-dependent mechanism and activation of K(+) channels.

Dilatation of cerebral arterioles in response to arachidonic acid is dependent on activity of cyclooxygenase. In this study, we examined mechanisms that mediate dilatation of the basilar artery in response to arachidonate. Diameter of the basilar artery (baseline diameter = 216 +/- 7 micrometer) (means +/- SE) was measured using a cranial window in anesthetized rats. Arachidonic acid (10 and 100 microM) produced concentration-dependent vasodilatation that was not inhibited by indomethacin (10 mg/kg iv) or N(G)-nitro-L-arginine (100 microM) but was inhibited markedly by baicalein (10 micrometerM) or nordihydroguaiaretic acid (NDGA; 10 microM), inhibitors of the lipoxygenase pathway. Dilatation of the basilar artery was also inhibited markedly by tetraethylammonium ion (TEA; 1 mM) or iberiotoxin (50 nM), inhibitors of calcium-dependent potassium channels. For example, 10 microM arachidonate dilated the basilar artery by 19 +/- 7 and 1 +/- 1% in the absence and presence of iberiotoxin, respectively. Measurements of membrane potential indicated that arachidonate produced hyperpolarization of the basilar artery that was blocked completely by TEA. Incubation with [(3)H]arachidonic acid followed by reverse-phase and chiral HPLC indicated that the basilar artery produces relatively small quantities of prostanoids but large quantities of 12(S)-hydroxyeicosatetraenoic acid (12-S-HETE), a lipoxygenase product. Moreover, the production of 12-HETE was inhibited by baicalein or NDGA. These findings suggest that dilatation of the basilar artery in response to arachidonate is mediated by a product(s) of the lipoxygenase pathway, with activation of calcium-dependent potassium channels and hyperpolarization of vascular muscle.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed2001

Gene transfer of extracellular superoxide dismutase increases superoxide dismutase activity in cerebrospinal fluid.

BACKGROUND AND PURPOSE: Copper-zinc superoxide dismutase (CuZnSOD) is expressed intracellularly, while extracellular SOD (EC-SOD) is released from cells. The purpose of this study was to determine whether gene transfer of CuZnSOD increases SOD activity predominantly in tissues, and gene transfer of EC-SOD increases SOD activity in cerebrospinal fluid (CSF). We also determined whether heparin or dextran sulfate releases EC-SOD into CSF. METHODS: We injected recombinant adenoviruses expressing EC-SOD (AdEC-SOD), CuZnSOD (AdCuZnSOD), or beta-galactosidase (Adbeta-gal) into the cisterna magna of rabbits. RESULTS: Total SOD activity in CSF was 39+/-11 U/mL (mean+/-SE) before virus injection. Three days later, total SOD activity in CSF increased to 148+/-22 U/mL after AdEC-SOD and 92+/-10 U/mL after AdCuZnSOD (P:<0.05 versus AdEC-SOD), with no change after Adbeta-gal (49+/-5 U/mL). EC-SOD protein was detected in CSF after AdEC-SOD but not AdCuZnSOD or Adbeta-gal. Injection of heparin or dextran sulfate into the cisterna magna increased total SOD activity 27-fold and 32-fold over basal values, respectively, in CSF of rabbits that received AdEC-SOD. In contrast to effects in CSF, total SOD activity in basilar artery and meninges was significantly higher after AdCuZnSOD and tended to be higher after AdEC-SOD than after Adbeta-gal. CONCLUSIONS: -We have developed a method for intracranial gene transfer of CuZnSOD and EC-SOD. After gene transfer, CuZnSOD was expressed mainly in tissues, and EC-SOD was released into the CSF, especially after injection of heparin or dextran sulfate. Gene transfer of different isoforms of SOD may be useful in studies of cerebral vascular physiology and pathophysiology.

Adenoviridae↗

PubMed2001

Mechanisms that produce nitric oxide-mediated relaxation of cerebral arteries during atherosclerosis.

BACKGROUND AND PURPOSE: The first goal of the present study was to examine the hypothesis that relaxation of cerebral arteries to nitric oxide in primates is dependent on activation of soluble guanylate cyclase (sGC). The second goal was to determine whether the role of sGC in mediating responses to nitric oxide is altered in atherosclerosis. METHODS: Basilar arteries from normal and atherosclerotic monkeys were studied in vitro. After precontraction with prostaglandin F(2alpha) (0.1 to 1 micromol/L), concentration-response curves to authentic nitric oxide (1 nmol/L to 1 micromol/L), sodium nitroprusside (10 nmol/L to 10 micromol/L; a nitric oxide donor), and papaverine (10 nmol/L to 10 micromol/L; a non-nitric oxide, non-sGC-dependent stimulus) were generated in the presence and absence of 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 1 and 10 micromol/L; an inhibitor of sGC). The effect of ODQ on basal tone of basilar arteries from normal and atherosclerotic monkeys was also examined. RESULTS: Nitric oxide, sodium nitroprusside, and papaverine produced relaxation that was similar (P:>0.05) in normal and atherosclerotic monkeys. ODQ produced marked inhibition (P:<0.05) of vasorelaxation in response to nitric oxide and nitroprusside but not papaverine. For example, relaxation of the basilar artery in response to nitric oxide (0.1 micromol/L) was inhibited by approximately 85% and 73% by ODQ (1 micromol/L) in normal and atherosclerotic monkeys, respectively. ODQ produced contraction of the basilar arteries, and the increase in tension to ODQ was greater in normal (2.7+/-0.3 g; mean+/-SE) than in atherosclerotic monkeys (1.4+/-0.4 g; P:<0.05). In contrast, contraction to prostaglandin F(2alpha) was similar in the basilar artery from normal and atherosclerotic monkeys. CONCLUSIONS: These findings suggest that (1) relaxation of cerebral arteries in primates in response to nitric oxide is normally dependent, in large part, on activation of sGC and (2) the influence of sGC (via reduced production and/or activity of basal nitric oxide) on cerebral vascular tone is reduced in atherosclerosis.

Animals↗

PubMed2001

NO-dependent vasorelaxation is impaired after gene transfer of inducible NO-synthase.

Proinflammatory stimuli produce expression of inducible NO-synthase (iNOS) within blood vessels and are associated with impaired endothelium-dependent relaxation. Gene transfer of iNOS was used to test the hypothesis that expression of iNOS in blood vessels produces impairment of NO-dependent relaxation as well as contraction. An adenoviral vector containing cDNA for murine iNOS, AdCMViNOS, and a control virus, AdCMVBglII, were used for gene transfer to rabbit carotid arteries in vitro and in vivo. After gene transfer of iNOS in vitro, contractile responses to KCl, phenylephrine, and U46619 were impaired. Relaxation in response to acetylcholine, ADP, A23187, and nitroprusside was also impaired. For example, maximum relaxation of vessels to acetylcholine (10 micromol/L) was 78+/-4% (mean+/-SE) after AdBglII (10(10.5) plaque-forming units) and 34+/-5% after AdiNOS (10(10.5) plaque-forming units, P<0.05). NO-independent relaxation in response to 8-bromo-cGMP and papaverine was not impaired after AdiNOS. Contraction and relaxation were improved in carotid arteries expressing iNOS by aminoguanidine and L-N-iminoethyl lysine, inhibitors of iNOS. After intraluminal gene transfer of iNOS in vivo, contraction of vessels in vitro was normal, but responses to acetylcholine were impaired. In summary, the major finding is that NO-dependent relaxation is impaired in arteries after gene transfer of iNOS in vitro and in vivo. Thus, expression of iNOS per se impairs NO-dependent relaxation.

Adenoviridae↗

PubMed2000

Gene transfer of calcitonin gene-related peptide prevents vasoconstriction after subarachnoid hemorrhage.

We sought to determine whether adenovirus-mediated gene transfer in vivo of calcitonin gene-related peptide (CGRP), a potent vasodilator, ameliorates cerebral vasoconstriction after experimental subarachnoid hemorrhage (SAH). Arterial blood was injected into the cisterna magna of rabbits to mimic SAH 5 days after injection of AdRSVCGRP (8x10(8) pfu), AdRSVbetagal (control virus), or vehicle. After injection of AdRSVCGRP, there was a 400-fold increase in CGRP in cerebrospinal fluid. Contraction of the basilar artery to serotonin in vitro was greater in rabbits after SAH than after injection of artificial cerebrospinal fluid (P<0.001). Contraction to serotonin was less in rabbits with SAH after AdRSVCGRP than after AdRSVbetagal or vehicle (P:<0.02). Basal diameter of the basilar artery before SAH (measured with digital subtraction angiogram) was 13% greater in rabbits treated with AdRSVCGRP than in rabbits treated with vehicle or AdRSVbetagal (P:<0.005). In rabbits treated with vehicle or AdRSVbetagal, arterial diameter after SAH was 25+/-3% smaller than before SAH (P<0.0005). In rabbits treated with AdRSVCGRP, arterial diameter was similar before and after SAH and was reduced by 19+/-3% (P<0.01) after intracisternal injection of CGRP-(8-37) (0.5 nmol/kg), a CGRP(1) receptor antagonist. To determine whether gene transfer of CGRP after SAH may prevent cerebral vasoconstriction, we constructed a virus with a cytomegalovirus (CMV) promoter, which results in rapid expression of the transgene product. Treatment of rabbits with AdCMVCGRP after experimental SAH prevented constriction of the basilar artery 2 days after SAH. Thus, gene transfer of CGRP prevents cerebral vasoconstriction in vivo after experimental SAH.

Adenoviridae↗

PubMed2000

Gene transfer of endothelial nitric oxide synthase but not Cu/Zn superoxide dismutase restores nitric oxide availability in the SHRSP.

OBJECTIVE: Previous studies from our group have shown a deficit in nitric oxide (NO) bioavailability and an excess production of the superoxide anion (O(2)(-)) in the stroke prone spontaneously hypertensive rat (SHRSP) compared to the normotensive Wistar Kyoto (WKY) strain. This present study has investigated whether adenoviral-mediated gene transfer of human eNOS or Cu/ZnSOD can alter the NO/O(2)(-) balance, thereby improving endothelial function. METHODS: A recombinant adenovirus, Ad/Hu/eNOS, containing the human eNOS cDNA fragment was generated by homologous recombination in 293 cells. Ad/Hu/eNOS or Ad/Cu/ZnSOD was delivered into SHRSP carotid arteries in vivo, using a titre of 2x10(9)-2x10(10) plaque forming units (pfu)/ml, and the effect on gene expression was observed 24 h later. RESULTS: Western blotting confirmed increased enzyme levels of eNOS and Cu/ZnSOD in the viral-infused vessels. Ex vivo, the pressor response to phenylephrine (PE) in the presence of L-NAME was increased in the eNOS-infused arteries relative to the contralateral controls, indicating restoration of basal NO availability to that observed in untreated control WKY rats. Infusion of the SOD virus produced a statistically insignificant increase in NO bioavailability. CONCLUSIONS: Our results support our previous findings obtained using a bovine eNOS recombinant adenovirus, that recombinant adenoviral gene transfer of human eNOS has a significant effect on NO bioavailability. In contrast, AdCu/ZnSOD gene transfer does not elicit an effect in our model. These results indicate that short-term overexpression of a recombinant eNOS, but not Cu/ZnSOD gene, in carotid arteries of the SHRSP is an effective means of locally increasing NO bioavailability to improve endothelial function.

Adenoviridae↗

PubMed2000

Adenovirus-mediated gene transfer to cerebral circulation.

Gene therapy may, be a promising approach for treatment of cerebrovascular disease. An adenoviral vector encoding beta-galactosidase was administered intracisternally or intraventricularly into the brain of rats. Efficient expression of the reporter gene was observed at the cerebral blood vessels and perivascular tissues. When the adenoviral vector was delivered into CSF of dogs suffering from subarachnoid hemorrhage, prominent expressions of transgene were observed. Introduction of the vector to the ischemic brain of rats provided efficient transgene expression in the peri-ischemic area. Therefore, gene transfer to the cerebral blood vessel and brain may be a promising approach for gene therapy of stroke. Atherosclerotic lesion plays an important role in stroke. We evaluated efficacy of adenovirus-mediated gene transfer to the atherosclerotic vessels from monkeys and rabbits using an ex vivo gene transfer system. Efficiency of transgene expression in the atherosclerotic endothelium was better than that of normal vessels in both animals. Thus, the endothelium of atherosclerotic vessels may be a good target for gene therapy. Next, we transfected atherosclerotic carotid arteries from rabbits with an adenoviral vector encoding endothelial nitric oxide synthase (eNOS). After overexpression of eNOS in the atherosclerotic arteries, the response to acetylcholine was augmented, showing similar relaxation with normal vessels. These results suggest that gene transfer to atherosclerotic vessels improves endothelial function, which may be a new therapeutic approach for cerebrovascular disease.

Adenoviridae↗

PubMed2000

Gene transfer of endothelial nitric oxide synthase improves relaxation of carotid arteries from diabetic rabbits.

BACKGROUND: Diabetes mellitus is associated with impairment of NO-mediated vascular relaxation. The purpose of this study was to determine whether adenovirus-mediated gene transfer of endothelial NO synthase (eNOS) or Cu/Zn superoxide dismutase (SOD1) improves responsiveness to acetylcholine in alloxan-induced diabetic rabbits. METHODS AND RESULTS: After 8 weeks, plasma glucose was greater in diabetic rabbits (418+/-35 mg/dL) (mean+/-SEM) than in normal rabbits (105+/-4 mg/dL). Carotid arteries were removed and cut into ring segments. Arteries were incubated for 2 hours with adenoviral vectors driven by a CMV promoter expressing beta-galactosidase (beta-gal), eNOS, SOD1, or vehicle. After incubation with virus, arteries were incubated for an additional 24 hours to allow transgene expression. Vascular reactivity was examined by recording isometric tension. After precontraction with phenylephrine, responses to the endothelium-independent vasodilator sodium nitroprusside were similar in diabetic and normal arteries. Endothelium-dependent relaxation to acetylcholine (3x10(-6) mol/L) was significantly less in arteries from diabetic animals (68+/-5%) than in normal vessels (90+/-3%). Adenoviral transfection of arteries with eNOS improved relaxation in response to acetylcholine in diabetic (EC(50) eNOS=0.64+/-0.12x10(-7) mol/L versus vehicle =1. 70+/-0.43x10(-7) mol/L) but not normal arteries. Vasorelaxation in response to acetylcholine was inhibited by N(omega)-nitro-L-arginine (100 micromol/L) in all groups. Responses to acetylcholine were unchanged after gene transfection of SOD1 or beta-gal in arteries from diabetic or normal rabbits. CONCLUSIONS: Adenovirus-mediated gene transfer of eNOS, but not SOD, improves impaired NO-mediated relaxation in vessels from diabetic rabbits.

Acetylcholine↗

PubMed2000

In vivo gene transfer of prepro-calcitonin gene-related peptide to the lung attenuates chronic hypoxia-induced pulmonary hypertension in the mouse.

BACKGROUND: Calcitonin gene-related peptide (CGRP) is believed to play an important role in maintaining low pulmonary vascular resistance (PVR) and in modulating pulmonary vascular responses to chronic hypoxia; however, the effects of adenovirally mediated gene transfer of CGRP on the response to hypoxia are unknown. METHODS AND RESULTS: In the present study, an adenoviral vector encoding prepro-CGRP (AdRSVCGRP) was used to examine the effects of in vivo gene transfer of CGRP on increases in PVR, right ventricular mass (RVM), and pulmonary vascular remodeling that occur in chronic hypoxia in the mouse. Intratracheal administration of AdRSVCGRP, followed by 16 days of chronic hypoxia (FIO(2) 0.10), increased lung CGRP and cAMP levels. The increase in pulmonary arterial pressure (PAP), PVR, RVM, and pulmonary vascular remodeling in response to chronic hypoxia was attenuated in animals overexpressing prepro-CGRP, whereas systemic pressure was not altered while in chronically hypoxic mice, angiotensin II and endothelin-1-induced increases in PAP were reduced, whereas decreases in PAP in response to CGRP and adrenomedullin were not changed and decreases in PAP in response to a cAMP phosphodiesterase inhibitor were enhanced by AdRSVCGRP. CONCLUSIONS: In vivo CGRP lung gene transfer attenuates the increase in PVR and RVM, pulmonary vascular remodeling, and pressor responses in chronically hypoxic mice, suggesting that CGRP gene transfer alone and with a cAMP phosphodiesterase inhibitor may be useful for the treatment of pulmonary hypertensive disorders.

Adenoviridae↗

PubMed2000

Gene therapy of hypertensive vascular injury.

Hypertension and vascular injury usually require prolonged treatment, and compliance is a key to efficacy for pharmacologically-based antihypertensive therapy. Gene therapy has the potential to be long lasting, with few side effects. Recent studies have provided promising results, in which hypertension can be treated by either augmentation of vasodilation or inhibition of vasoconstriction through gene transfer in experimental models. Gene transfer is also becoming useful for the study of mechanisms of physiologic and pathophysiologic conditions, including hypertension. In this mini-review, we summarize some recent studies in this area of research, and suggest some areas where progress is needed to advance the research toward gene therapy.

Gene Transfer Techniques↗