Barbara Deodato

Genistein supplementation and estrogen replacement therapy improve endothelial dysfunction induced by ovariectomy in rats

BACKGROUND We investigated the effect of genistein, a phytoestrogen derived from a soy diet with a flavonoid chemical structure, on endothelial dysfunction induced by estrogen deficiency in rats. METHODS Female mature Sprague-Dawley rats were subjected to a bilateral ovariectomy (OVX rats). Sham-operated animals (Sham OVX rats) were used as controls. Three weeks after surgery animals were randomized to the following treatments: genistein (0.2 mg/kg/day, s.c. for 4 weeks), 17 beta-estradiol (20 micrograms/kg/day, s.c. for 4 weeks) or their respective vehicles. Mean arterial blood pressure (MAP), heart rate (HR), total plasma cholesterol, plasma estradiol, plasma genistein levels and uterine weights were studied. Furthermore, we investigated acetylcholine (ACh 10 nM-10 microM) and sodium nitroprusside: (SN 15-30 nM) induced relaxation of aortic rings as well as NG-L-arginine (L-NMA: 10-100 microM) induced vasoconstriction in phenylephrine precontracted aortic segments and calcium-dependent nitric oxide synthase (cNOS) activity in homogenates of lungs taken from both sham OVX and OVX rats. RESULTS Untreated OVX rats had, compared with sham OVX animals, unchanged body weight, MAP, HR and plasma cholesterol. In contrast ovariectomy impaired endothelial responses, blunted L-NMA induced contraction (L-NMA 100 microM: Sham OVX = 2.1 +/- 0.2 g/mg tissue; OVX = 1.7 +/- 0.4 g/mg tissue) and reduced cNOS activity. Treatment with 17 beta-estradiol increased the hormone plasma levels, reverted the endothelial dysfunction and increased cNOS activity in lung homogenates. Genistein supplementation enhanced the circulating levels of the phytoestrogen and affected NOS activity and endothelial dysfunction to the same extent. CONCLUSIONS Our data suggest that genistein and 17 beta-estradiol show overlapping effects on experimental endothelial dysfunction.

Cardioprotection by the phytoestrogen genistein in experimental myocardial ischaemia-reperfusion injury.

Soybean phytoestrogens have no oestrogen agonist effects on the reproductive system and therefore it is reasonable to explore the potential of these naturally occurring plant oestrogens in the cardiovascular pathology. We therefore investigated the effects of genistein in a rat model of myocardial ischaemia‐reperfusion injury. Anaesthetized rats were subjected to total occlusion (45 min) of the left main coronary artery followed by 5 h reperfusion (MI/R). Sham operated rats were used as controls. Myocardial necrosis, myocardial myeloperoxidase activity (MPO), serum creatinine phosphokinase activity (CPK), serum and macrophage Tumour Necrosis Factor‐α (TNF‐α), cardiac intercellular adhesion molecule‐1 (ICAM‐1) immunostaining, cardiac mRNA for ICAM‐1 evaluated by the means of reverse transcriptase polymerase chain reaction (RT–PCR), ventricular arrhythmias and myocardial contractility (left ventricle dP/dtmax) were evaluated. Myocardial ischaemia and reperfusion in untreated rats produced marked myocardial necrosis, increased serum CPK activity and MPO activity both in the area‐at‐risk and in the necrotic area, reduced myocardial contractility, caused ventricular arrhythmias and induced a marked increase in serum and macrophage TNF‐α. Furthermore myocardial ischaemia‐reperfusion injury increased ICAM‐1 expression in the myocardium. Administration of genistein (1 mg kg−1, i.v., 5 min after coronary artery occlusion) lowered myocardial necrosis and MPO activity in the area‐at‐risk and in the necrotic area, decreased serum CPK activity, increased myocardial contractility, decreased the occurrence of ventricular arrhythmias, reduced serum and macrophages levels of TNF‐α and blunted ICAM‐1 expression in the injured myocardium. Finally genistein added in vitro to peritoneal macrophages collected from untreated rats subjected to myocardial ischaemia‐reperfusion injury significantly reduced TNF‐α production. Our data suggest that genistein limits the inflammatory response and protects against myocardial ischaemia‐reperfusion injury.

IRFI 042, a novel dual vitamin E-like antioxidant, inhibits activation of nuclear factor-κB and reduces the inflammatory response in myocardial ischemia–reperfusion injury

BACKGROUND Nuclear factor-kappaB (NF-kappaB) is a ubiquitous rapid response transcription factor involved in inflammatory reactions which exerts its effect by expressing cytokines, chemokines, and cell adhesion molecules. Oxidative stress causes NF-kappaB activation. IRFI 042 is a novel dual vitamin E-like antioxidant and we, therefore, investigated its ability to protect the heart from oxidative stress and to halt the inflammatory response in a model of myocardial ischaemia-reperfusion injury. METHODS Anaesthetized rats were subjected to total occlusion (45 min) of the left main coronary artery followed by 5-h reperfusion (MI/R). Sham myocardial ischaemia rats (sham-operated rats) were used as controls. Myocardial necrosis, cardiac output, cardiac and plasma vitamin E levels, myocardial malondialdehyde (MAL), cardiac SOD activity and elastase content (an index of leukocyte infiltration), hydroxyl radical (OH&z.ccirf;) formation, cardiac amount of mRNA codifying for ICAM-1 (evaluated by the means of reverse transcriptase polymerase chain reaction) and ICAM-1 immunostaining in the at-risk myocardium were investigated. NF-kappaB activation and the inhibitory protein of NF-kappaB, I-kappaBalpha, were also studied in at-risk myocardium by using electrophoretic mobility shift assay (EMSA) and Western blot analysis, respectively. RESULTS The ischaemia-reperfusion model produced wide heart necrosis (area at risk-necrotic area=52+/-5%; necrotic area-left ventricle=28+/-3%), increased cardiac MAL, an index of lipid peroxidation (area at risk=62.5+/-3.9 nmol/g tissue; necrotic area=80.3+/-5.1 nmol/g tissue), induced tissue neutrophil infiltration, and caused a marked decrease in endogenous antioxidants. Furthermore, myocardial ischaemia plus reperfusion caused in the area at risk peak message for ICAM-1 at 3 h of reperfusion and increased cardiac ICAM-1 immunostaining at 5 h of reperfusion. NF-kappaB activation was also evident at 0.5 h of reperfusion and reached its maximum at 2 h of reperfusion. I-kappaBalpha was markedly decreased at 45 min of occlusion; peak reduction was observed at 1 h of reperfusion and thereafter it was gradually restored. Intraperitoneal administration of IRFI 042 (5, 10, 20 mg/kg, 5 min after reperfusion) reduced myocardial necrosis expressed as a percentage either of the area at risk (18+/-4%) or the total left ventricle (11+/-2%), and improved cardiac output. This treatment also limited membrane lipid peroxidation in the area at risk (MAL=14.3+/-2.5 nmol/g tissue) and in the necrotic area (MAL=26.5+/-3.7 nmol/g tissue), restored the endogenous antioxidants vitamin E and superoxide dismutase, and inhibited detrimental hydroxyl radical formation. Finally, IRFI 042 blocked the activation of NF-kappaB, reduced cardiac ICAM-1 expression, and blunted tissue elastase content, an index of leukocytes accumulation at the site of injury. CONCLUSIONS Our data suggest that IRFI 042 is cardioprotective during myocardial infarction by limiting reperfusion-induced oxidative stress and by halting the inflammatory response.

Effect of recombinant adeno-associated virus vector-mediated vascular endothelial growth factor gene transfer on wound healing after burn injury.

ObjectiveThe purpose of this study was to investigate the effect of recombinant adeno-associated viral (rAAV) vector-mediated human vascular endothelial growth factor (VEGF165) transfer on experimental burn wounds. DesignRandomized experiment. SettingResearch laboratory. SubjectsC57BL/6 male mice weighing 25–30 g. InterventionsMice were immersed in 80°C water for 10 secs to achieve a partial-thickness scald burn. Animals were randomized to receive at two injection sites on the edge of the burn either 1011 copies of the rAAV-VEGF165 or the vector carrying the control and inert gene &bgr;-galactosidase (rAAV-LacZ). On day 14 the animals were killed. Burn areas were used for histologic examination, evaluation of VEGF expression (immunohistochemistry) and VEGF wound content (enzyme-linked immunosorbent assay), determination of wound nitrite, and measurement of messenger RNA (mRNA) for endothelial and inducible nitric oxide synthase (eNOS and iNOS). Measurements and Main ResultsrAAV-VEGF165 increased epithelial proliferation, angiogenesis, and maturation of the extracellular matrix. Furthermore, gene transfer enhanced VEGF expression, studied by immunohistochemistry, and the wound content of the mature protein (rAAV-LacZ, 11 ± 5 pg/wound; rAAV-VEGF165, 104 ± 7 pg/wound). Moreover, VEGF165 gene transfer increased wound content of nitrate. Finally, rAAV-VEGF165 administration enhanced the messenger RNA for eNOS (rAAV-VEGF165, 1.1 ± 0.2 relative amount of eNOS mRNA; rAAV-LacZ, 0.66 ± 0.3 relative amount of eNOS mRNA) and iNOS (rAAV-VEGF165, 0.8 ± 0.09 relative amount of iNOS mRNA; rAAV-LacZ, 0.45 ± 0.05 relative amount of iNOS mRNA). ConclusionOur study suggests that rAAV-VEGF gene transfer may be an effective therapeutic approach to improve clinical outcomes after thermal injury.

Enhancement of expression of vascular endothelial growth factor after adeno-associated virus gene transfer is associated with improvement of brain ischemia injury in the gerbil.

Angiogenesis induced by growth factors may represent a rational therapy for patients with stroke. Vascular endothelial growth factor (VEGF) plays a pivotal role in angiogenesis and VEGF expression is enhanced in the post-ischemic brain. VEGF induced by brain hypoxia can lead to the growth of new vessels and may represent a natural protective mechanism improving survival after stroke. In the light of these findings we investigated changes of VEGF expression in different brain regions after intracerebroventricular injection of adeno-associated virus transferring gene for VEGF (rAAV-VEGF) in the gerbil, and after transient brain ischemic injury, we studied the effects of rAAV-VEGF injection on survival, brain edema, delayed neuronal death in the CA1 area and learning ability. Treatment with rAAV-VEGF 6 days or 12 days before ischemia significantly improves survival, brain edema and CA1 delayed neuronal death and post-ischemic learning evaluated by passive avoidance test. Animals treated with rAAV-VEGF showed in the thalamus and the cortex, a significant positive immunostaining for VEGF similar to those subjected to brain ischemia and not treated with rAAV-VEGF. These data represent a further contribution to a possible employment of gene therapy by using rAAV-VEGF in brain ischemia and indicate that thalamus and cortex may be targets for neuroprotective effects of VEGF.

Gene transfer of IκBα limits infarct size in a mouse model of myocardial ischemia-reperfusion injury

Nuclear factor-κB (NF-κB) plays a central role in myocardial ischemia-reperfusion (MI/R) injury. The inhibitory protein IκBα prevents its activation. We investigated the effects of adeno-associated viral vector-mediated IκBα gene transfer in MI/R injury. Male C57BL/6 mice were randomized to receive a recombinant adeno-associated virus (rAAV) encoding the gene for the NF-κB inhibitory protein IκBα (rAAV- IκBα) or the β-galactosidase gene (a control and inert gene; rAAV-LacZ), both at a dose of 1011 copies. Four weeks later anesthetized animals were subjected to total occlusion (45 minutes) of the left main coronary artery followed by 5 hours of reperfusion. MI/R produced a wide infarct size (IF/area-at-risk = 56 ± 8%; IF/left ventricle = 44 ± 5%) and tissue neutrophil infiltration, studied by means of elastase activity (area-at-risk = 2.5 ± 0.4 μg/gm tissue; infarct area = 2.9 ± 0.6 μg/gm tissue). Furthermore MI/R caused peak message for intercellular adhesion molecule-1 (ICAM-1) in the area-at-risk at 3 hours of reperfusion (1.2 ± 0.4 relative amount of cardiac ICAM-1 mRNA). NF-κB activation was evident at 0.5 hours of reperfusion and reached its maximum increase at 2 hours of reperfusion. rAAV-IκBα injection reduced infarct size (IF/area-at-risk = 19 ± 3%; IF/left ventricle = 10 ± 2%; p < 0.001), blocked NF-κB activation, diminished cardiac ICAM-1 expression (0.4 ± 0.02 relative amount of cardiac ICAM-1 mRNA; p < 0.001), and blunted leukocyte accumulation (area-at-risk = 0.6 ± 0.05 μg/gm tissue; infarct area = 0.4 ± 0.02 μg/gm tissue; p < 0.001). Our data indicate that rAAV-IκBα may be useful for MI/R gene therapy.

Crucial role of nuclear factor-κB in neointimal hyperplasia of the mouse carotid artery after interruption of blood flow

We used a molecular genetics approach to investigate the role of nuclear factor-kappaB (NF-kappaB) in neointimal hyperplasia induced by flow interruption of carotid artery in mice. Wild type mice (WT mice) and mice rendered deficient in p105, the precursor of p50, one of the components of the multimeric transcription factor NF-kappaB (NF-kappaB knockout mice; KO mice), were subjected to a complete ligation of the left common carotid artery. Morphometric analysis of the structural alteration caused by the disruption of the arterial blood flow was performed 14 days after surgery. Furthermore the expression of intercellular adhesion molecule-1 (ICAM-1) in injured arteries was evaluated 4 days after artery ligation by the means of reverse transcriptase polymerase chain reaction (RT-PCR) and quantification of the ICAM-1 protein levels. In a separate experiment normal mice were randomly assigned to receive a recombinant adeno-associated virus (rAAV) encoding the gene for the NF-kappaB inhibitory protein IkappaBalpha (rAAV-IkappaBalpha), or the beta-galactosidase gene (rAAV-LacZ), both at a dose of 10(11) copies and 2 weeks later were subjected to the complete ligation of the left carotid artery. NF-kappaB activity (studied by means of electrophoretic mobility shift assay-EMSA), IkappaBalpha expression (evaluated by Western blot analysis) ICAM-1 evaluation (RT-PCR and quantification of the protein levels) and a morphometric analysis were evaluated in the injured arteries. Disruption of the arterial blood flow caused a marked neointimal hyperplasia. The mean intimal area was 0.023+/-0.002 mm(2) in wild type mice compared with 0.002+/-0.001 mm(2) in NF-kappaB knockout mice. ICAM-1 expression was 1.7+/-0.8 relative amount of ICAM-1 mRNA in wild type mice compared with 0.4+/-0.06 relative amount of ICAM-1 mRNA in NF-kappaB knockout mice. ICAM-1 protein levels were also significantly reduced in NF-kappaB knockout mice. Injured arteries treated with rAAV-IkappaBalpha had a greater expression of IkappaBalpha and lower NF-kappaB activity, when compared with vessels treated with rAAV-LacZ. Furthermore, ICAM-1 expression was markedly attenuated by the treatment with rAAV-IkappaBalpha (rAAV-LacZ=1.6+/-0.8 relative amount of ICAM-1 mRNA; rAAV-IkappaBalpha=0.55+/-0.04 relative amount of ICAM-1 mRNA). ICAM-1 protein levels were also significantly decreased in rAAV-IkappaBalpha treated mice. Finally the mean intimal area was 0.028+/-0.003 mm(2) in left carotid arteries treated with rAAV-LacZ whereas it was 0.003+/-0.004 mm(2) in vessels treated with rAAV-IkappaBalpha. Our data indicate that NF-kappaB plays a crucial role in neointimal hyperplasia induced by flow cessation in the mouse carotid artery, and in addition suggest that rAAV-mediated gene transfer of IkappaBalpha might represent a novel therapeutic approach to the treatment of restenosis.

The phytoestrogen α-zearalenol reverses endothelial dysfunction induced by oophorectomy in rats

It has been shown recently that α-zearalenol, a resorcyclic acid lactone, prevents bone loss in a rat model of postmenopausal bone loss. We have therefore investigated the effects of this phytoestrogen on endothelial dysfunction induced by estrogen deficiency in rats. Female mature Sprague-Dawley rats underwent a bilateral oophorectomy (OVX rats). Sham-operated animals (sham OVX rats) were used as controls. Three weeks after surgery, animals were randomized to the following treatments: α-zearalenol (1 mg/kg/day, im, for 4 weeks), 17β-estradiol (20 μg/kg/day, im, for 4 weeks), or their vehicle (100 μl, im, of cottonseed oil). Two other groups of rats were treated with α-zearalenol or 17β-estradiol plus the pure estrogen receptor antagonist ICI 182780 (2.5 mg/kg/day, im, for 4 weeks). Mean arterial blood pressure (MAP), heart rate (HR), total plasma cholesterol, plasma estradiol, and plasma α-zearalenol were studied. We also investigated endothelial-dependent (acetylcholine, 10 nm to 10 μm) and endothelial-independent (sodium nitroprusside, 15 nm to 30 nm) relaxation of aortic rings, as well as N(G)-methyl-l-arginine (L-NMA: 10 to 100 μm)–induced vasoconstriction and calcium-dependent nitric oxide synthase (cNOS) activity in homogenates of lungs taken from both sham OVX rats and OVX rats. Untreated OVX rats had, compared with sham OVX animals, unchanged body weight, MAP, HR, and plasma cholesterol. In contrast oophorectomy reduced plasma estradiol levels (OVX, 2 ± 0.5 pg/ml; sham OVX, 35 ± 6 pg/ml), impaired endothelial-dependent relaxation and blunted L-NMA–induced contraction (L-NMA 100 μm: sham OVX, 2.7 ± 0.3 g/mg tissue; OVX, 1.3 ± 0.1 g/mg tissue). Moreover OVX rats showed a reduced calcium-dependent NO synthase (cNOS) activity. Treatment with α-zearalenol or with 17β-estradiol reverted the endothelial dysfunction and increased cNOS activity in lung homogenates. These effects were abolished by the pure estrogen receptor antagonist ICI 182780. Our data suggest that α-zearalenol improves endothelial-dependent relaxation in OVX rats through an estrogen receptor–mediated effect.

Protective effects of Cyclosporin‐A in splanchnic artery occlusion shock

Cyclosporin A (CsA) is an immunosuppressant drug that inhibits nitric oxide (NO) synthase induction in vascular smooth muscle cells. Splanchnic artery occlusion (SAO) shock is a lethal type of shock characterized by a marked vascular dysfunction in which the L‐arginine/nitric oxide pathway plays an important role. We investigated whether CsA exerts protective effects in SAO shock by interfering with the L‐arginine/nitric oxide pathway. Male anaesthetized rats (n=156) were subjected to clamping of the splanchnic arteries for 45 min. This surgical procedure resulted in an irreversible state of shock (SAO shock). Sham operated animals were used as controls. SAO shocked rats had a decreased survival (86±6 min, while sham shocked rats survived more than 240 min), marked hypotension, increased serum levels of TNF‐α, enhanced plasma nitrite/nitrate concentrations (75±7.1 μM; sham shocked rats=1.6±0.5 μM) and enhanced inducible NO synthase (iNOS) protein induction and activity in the aorta. Moreover aortic rings from shocked rats showed a marked hyporeactivity to phenylephrine (PE, 1 nM–10 μM). CsA (0.25, 0.5 and 1 mg kg−1, 5 min after reperfusion) increased survival rate (SAO+CsA=236±9 min following the highest dose), reverted the marked hypotension, reduced plasma nitrite/nitrate concentration (11±5.2 μM following the highest dose), restored to control values the hyporeactivity to PE, and blunted iNOS protein induction and activity in aortic rings. The present data indicate that in an experimental rat model CsA may have antishock properties related to inhibition of L‐arginine/nitric oxide pathway.

The reduction of myocardial damage and leukocyte polymorphonuclear accumulation following coronary artery occlusion by the tyrosine kinase inhibitor tyrphostin AG 556

We investigated the effects of tyrophostin AG 556, a tyrosine kinase inhibitor, on the phenomenon of leukocyte accumulation during ischaemia and reperfusion of the myocardium. Male anaesthetized rats were subjected to total occlusion (45 min) of the left main coronary artery followed by 5 h reperfusion (MI/R). Sham myocardial ischaemia-reperfusion rats (Sham MI/R) were used as controls. Myocardial necrosis, myocardial myeloperoxidase activity (MPO), serum creatinine phosphokinase activity (CPK) serum Tumor Necrosis Factor (TNF-alpha) and Interleukin 6 (IL-6), cardiac intercellular adhesion molecule-1 (ICAM-1) and TNF-alpha expression and myocardial contractility (left ventricle dP/dt(max)) were evaluated. Myocardial ischaemia plus reperfusion in untreated rats produced marked myocardial necrosis, increased serum CPK activity (196.5 +/- 19 U/100 ml, at the end of reperfusion) and myeloperoxidase activity (MPO, a marker of leukocyte accumulation) both in the area-at-risk (4.5 +/- 0.5 U/g/tissue) and in necrotic area (8.2 +/- 1.2 U/g/tissue), reduced myocardial contractility (1,706 +/- 52 mmHg/s, at the end of reperfusion) and induced a marked increase in the serum levels of TNF-alpha (1,950 +/- 97 pg/ml, at 1 h of reperfusion) and IL-6 (998 +/- 16 U/ml, at the end of reperfusion). Finally, myocardial ischaemia-reperfusion injury also increased cardiac mRNA for TNF-alpha and ICAM-1 in the myocardium-at risk. Tyrphostin AG 556 (0.5, 1 and 2 mg/kg subcutaneously 5 min after the onset of reperfusion) lowered myocardial necrosis and myeloperoxidase activity in the area-at-risk (1.5 +/- 0.2 U/g/tissue, following the highest dose) and in necrotic area (2.9 +/- 0.3 U/g/tissue following the highest dose), decreased serum CPK activity (96 +/- 9 U/100 ml, at the end of reperfusion), lowered serum TNF-alpha and IL-6, increased myocardial contractility (2,096 +/- 88 mmHg s, at the end of reperfusion) and reduced cardiac mRNA levels for TNF-alpha and ICAM-1. The present data suggest that tyrosine kinase inhibitors protect against myocardial ischaemia-reperfusion injury by reducing leukocyte accumulation to the ischaemic myocardium.