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2.
Chest ; 143(2): 444-451, 2013 Feb 01.
Article in English | MEDLINE | ID: mdl-22922469

ABSTRACT

BACKGROUND: Acute exposure to high altitude stimulates free radical formation in lowlanders, yet whether this persists during chronic exposure in healthy, well-adapted and maladapted highlanders suffering from chronic mountain sickness (CMS) remains to be established. METHODS: Oxidative-nitrosative stress (as determined by the presence of the biomarkers ascorbate radical [A •- ], via electron paramagnetic resonance spectroscopy, and nitrite [NO 2 2 ], via ozone-based chemiluminescence) was assessed in venous blood of 25 male highlanders in Bolivia living at 3,600 m with CMS (n 5 13, CMS 1 ) and without CMS (n 5 12, CMS 2 ). Twelve age- and activity-matched, healthy, male lowlanders were examined at sea level and during acute hypoxia. We also measured fl ow-mediated dilatation (FMD), arterial stiffness defined by augmentation index normalized for a heart rate of 75 beats/min (AIx-75), and carotid intima-media thickness (IMT). RESULTS: Compared with normoxic lowlanders, oxidative-nitrosative stress was moderately increased in the CMS 2 group ( P , .05), as indicated by elevated A •- (3,191 457 arbitrary units [AU] vs 2,640 445 AU) and lower NO 2 2 (206 55 nM vs 420 128 nM), whereas vascular function remained preserved. This was comparable to that observed during acute hypoxia in lowlanders in whom vascular dysfunction is typically observed. In contrast, this response was markedly exaggerated in CMS 1 group (A •- , 3,765 429 AU; NO 2 2 , 148 50 nM) compared with both the CMS 2 group and lowlanders ( P , .05). This was associated with systemic vascular dysfunction as indicated by lower ( P , .05 vs CMS 2 ) FMD (4.2% 0.7% vs 7.6% 1.7%) and increased AIx-75 (23% 8% vs 12% 7%) and carotid IMT (714 127 m M vs 588 94 m M). CONCLUSIONS: Healthy highlanders display a moderate, sustained elevation in oxidative-nitrosative stress that, unlike the equivalent increase evoked by acute hypoxia in healthy lowlanders, failed to affect vascular function. Its more marked elevation in patients with CMS may contribute to systemic vascular dysfunction.


Subject(s)
Altitude Sickness/physiopathology , Altitude , Cardiovascular System/physiopathology , Hypoxia/physiopathology , Nitrosation/physiology , Oxidative Stress/physiology , Adaptation, Physiological/physiology , Altitude Sickness/metabolism , Antioxidants/metabolism , Bolivia , Carotid Intima-Media Thickness , Case-Control Studies , Free Radicals/metabolism , Heart Rate/physiology , Humans , Hypoxia/metabolism , Male , Middle Aged , Nitric Oxide/metabolism
3.
Circulation ; 125(15): 1890-6, 2012 Apr 17.
Article in English | MEDLINE | ID: mdl-22434595

ABSTRACT

BACKGROUND: Assisted reproductive technology (ART) involves the manipulation of early embryos at a time when they may be particularly vulnerable to external disturbances. Environmental influences during the embryonic and fetal development influence the individual's susceptibility to cardiovascular disease, raising concerns about the potential consequences of ART on the long-term health of the offspring. METHODS AND RESULTS: We assessed systemic (flow-mediated dilation of the brachial artery, pulse-wave velocity, and carotid intima-media thickness) and pulmonary (pulmonary artery pressure at high altitude by Doppler echocardiography) vascular function in 65 healthy children born after ART and 57 control children. Flow-mediated dilation of the brachial artery was 25% smaller in ART than in control children (6.7 ± 1.6% versus 8.6 ± 1.7%; P<0.0001), whereas endothelium-independent vasodilation was similar in the 2 groups. Carotid-femoral pulse-wave velocity was significantly (P<0.001) faster and carotid intima-media thickness was significantly (P<0.0001) greater in children conceived by ART than in control children. The systolic pulmonary artery pressure at high altitude (3450 m) was 30% higher (P<0.001) in ART than in control children. Vascular function was normal in children conceived naturally during hormonal stimulation of ovulation and in siblings of ART children who were conceived naturally. CONCLUSIONS: Healthy children conceived by ART display generalized vascular dysfunction. This problem does not appear to be related to parental factors but to the ART procedure itself. CLINICAL TRIAL REGISTRATION: URL: www.clinicaltrials.gov. Unique identifier: NCT00837642.


Subject(s)
Pulmonary Circulation , Reproductive Techniques, Assisted/adverse effects , Vascular Diseases/etiology , Adolescent , Adult , Brachial Artery/physiology , Carotid Intima-Media Thickness , Child , Female , Humans , Male , Middle Aged , Multivariate Analysis , Vasodilation
4.
Chest ; 141(1): 139-146, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21700688

ABSTRACT

BACKGROUND: Chronic mountain sickness (CMS) is a major public health problem characterized by exaggerated hypoxemia and erythrocytosis. In more advanced stages, patients with CMS often present with functional and structural changes of the pulmonary circulation, but there is little information on the systemic circulation. In patients with diseases associated with chronic hypoxemia at low altitude, systemic vascular function is altered. We hypothesized that patients with CMS have systemic vascular dysfunction that may predispose them to increased systemic cardiovascular morbidity. METHODS: To test this hypothesis, we assessed systemic endothelial function (by flow-mediated dilation [FMD]), arterial stiffness, and carotid intima-media thickness and arterial oxygen saturation (Sao(2)) in 23 patients with CMS without additional classic cardiovascular risk factors and 27 age-matched healthy mountain dwellers born and permanently living at 3,600 m. For some analyses, subjects were classified according to baseline Sao(2) quartiles; FMD of the highest quartile subgroup (Sao(2) ≥ 90%) was used as a reference value for post hoc comparisons. RESULTS: Patients with CMS had marked systemic vascular dysfunction as evidenced by impaired FMD (CMS, 4.6% ± 1.2%; control subjects, 7.6% ± 1.9%; P < .0001), greater pulse wave velocity (10.6 ± 2.1 m/s vs 8.4 ± 1.0 m/s, P < .001), and greater carotid intima-media thickness (690 ± 120 µm vs 570 ± 110 µm, P = .001). A positive relationship existed between Sao(2) and FMD (r = 0.62, P < .0001). Oxygen inhalation improved (P < .001) but did not normalize FMD in patients with CMS, although it normalized FMD in hypoxemic control subjects (Sao(2) < 90%) and had no detectable effect in normoxemic control subjects (Sao(2) ≥ 90%). CONCLUSIONS: Patients with CMS show marked systemic vascular dysfunction. Structural and functional alterations contribute to this problem that may predispose these patients to premature cardiovascular disease. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01182792; URL: www.clinicaltrials.gov.


Subject(s)
Altitude Sickness/physiopathology , Carotid Arteries/physiopathology , Vascular Stiffness/physiology , Vasodilation/physiology , Altitude , Altitude Sickness/blood , Altitude Sickness/therapy , Blood Flow Velocity , Carotid Arteries/diagnostic imaging , Carotid Intima-Media Thickness , Chronic Disease , Endothelium, Vascular/diagnostic imaging , Endothelium, Vascular/physiopathology , Follow-Up Studies , Humans , Male , Middle Aged , Oxygen Consumption , Oxygen Inhalation Therapy/methods , Prognosis , Reference Values , Retrospective Studies , Risk Factors , Ultrasonography, Doppler
5.
Am J Physiol Heart Circ Physiol ; 301(1): H247-52, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21536851

ABSTRACT

Insults during the fetal period predispose the offspring to systemic cardiovascular disease, but little is known about the pulmonary circulation and the underlying mechanisms. Maternal undernutrition during pregnancy may represent a model to investigate underlying mechanisms, because it is associated with systemic vascular dysfunction in the offspring in animals and humans. In rats, restrictive diet during pregnancy (RDP) increases oxidative stress in the placenta. Oxygen species are known to induce epigenetic alterations and may cross the placental barrier. We hypothesized that RDP in mice induces pulmonary vascular dysfunction in the offspring that is related to an epigenetic mechanism. To test this hypothesis, we assessed pulmonary vascular function and lung DNA methylation in offspring of RDP and in control mice at the end of a 2-wk exposure to hypoxia. We found that endothelium-dependent pulmonary artery vasodilation in vitro was impaired and hypoxia-induced pulmonary hypertension and right ventricular hypertrophy in vivo were exaggerated in offspring of RDP. This pulmonary vascular dysfunction was associated with altered lung DNA methylation. Administration of the histone deacetylase inhibitors butyrate and trichostatin A to offspring of RDP normalized pulmonary DNA methylation and vascular function. Finally, administration of the nitroxide Tempol to the mother during RDP prevented vascular dysfunction and dysmethylation in the offspring. These findings demonstrate that in mice undernutrition during gestation induces pulmonary vascular dysfunction in the offspring by an epigenetic mechanism. A similar mechanism may be involved in the fetal programming of vascular dysfunction in humans.


Subject(s)
Epigenesis, Genetic/physiology , Fetal Development/physiology , Pulmonary Circulation/physiology , Vascular Diseases/genetics , Vascular Diseases/physiopathology , Animals , Caloric Restriction , Cyclic N-Oxides/pharmacology , DNA Methylation/physiology , Diet , Endothelium, Vascular/physiology , Female , Fetal Development/drug effects , Fetal Development/genetics , Histone Deacetylase Inhibitors/pharmacology , Hypertrophy, Right Ventricular/etiology , Hypertrophy, Right Ventricular/physiopathology , Hypoxia/metabolism , Male , Mice , Mice, Inbred C57BL , Oxidative Stress/physiology , Pregnancy , Protein Synthesis Inhibitors/pharmacology , Pulmonary Circulation/drug effects , Pulmonary Circulation/genetics , Pulmonary Wedge Pressure/physiology , Spin Labels
6.
Circulation ; 122(5): 488-94, 2010 Aug 03.
Article in English | MEDLINE | ID: mdl-20644018

ABSTRACT

BACKGROUND: Adverse events in utero may predispose to cardiovascular disease in adulthood. The underlying mechanisms are unknown. During preeclampsia, vasculotoxic factors are released into the maternal circulation by the diseased placenta. We speculated that these factors pass the placental barrier and leave a defect in the circulation of the offspring that predisposes to a pathological response later in life. The hypoxia associated with high-altitude exposure is expected to facilitate the detection of this problem. METHODS AND RESULTS: We assessed pulmonary artery pressure (by Doppler echocardiography) and flow-mediated dilation of the brachial artery in 48 offspring of women with preeclampsia and 90 offspring of women with normal pregnancies born and permanently living at the same high-altitude location (3600 m). Pulmonary artery pressure was roughly 30% higher (mean+/-SD, 32.1+/-5.6 versus 25.3+/-4.7 mm Hg; P<0.001) and flow-mediated dilation was 30% smaller (6.3+/-1.2% versus 8.3+/-1.4%; P<0.0001) in offspring of mothers with preeclampsia than in control subjects. A strong inverse relationship existed between flow-mediated dilation and pulmonary artery pressure (r=-0.61, P<0.001). The vascular dysfunction was related to preeclampsia itself because siblings of offspring of mothers with preeclampsia who were born after a normal pregnancy had normal vascular function. Augmented oxidative stress may represent an underlying mechanism because thiobarbituric acid-reactive substances plasma concentration was increased in offspring of mothers with preeclampsia. CONCLUSIONS: Preeclampsia leaves a persistent defect in the systemic and the pulmonary circulation of the offspring. This defect predisposes to exaggerated hypoxic pulmonary hypertension already during childhood and may contribute to premature cardiovascular disease in the systemic circulation later in life.


Subject(s)
Hypertension, Pulmonary/etiology , Hypoxia/etiology , Peripheral Vascular Diseases/etiology , Pre-Eclampsia/physiopathology , Prenatal Exposure Delayed Effects/physiopathology , Adolescent , Age Factors , Carbon Monoxide/metabolism , Child , Echocardiography, Doppler , Female , Humans , Hypertension, Pulmonary/diagnostic imaging , Hypertension, Pulmonary/physiopathology , Hypoxia/physiopathology , Male , Oxidative Stress/physiology , Peripheral Vascular Diseases/physiopathology , Pregnancy , Pulmonary Wedge Pressure/physiology , Thiobarbituric Acid Reactive Substances/metabolism , Vasodilation/physiology , Ventricular Pressure/physiology , Young Adult
7.
Endocrinology ; 150(12): 5311-7, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19819971

ABSTRACT

Obesity and insulin resistance represent a problem of utmost clinical significance worldwide. Insulin-resistant states are characterized by the inability of insulin to induce proper signal transduction leading to defective glucose uptake in skeletal muscle tissue and impaired insulin-induced vasodilation. In various pathophysiological models, melatonin interacts with crucial molecules of the insulin signaling pathway, but its effects on glucose homeostasis are not known. In a diet-induced mouse model of insulin resistance and normal chow-fed control mice, we sought to assess the effects of an 8-wk oral treatment with melatonin on insulin and glucose tolerance and to understand underlying mechanisms. In high-fat diet-fed mice, but not in normal chow-fed control mice, melatonin significantly improved insulin sensitivity and glucose tolerance, as evidenced by a higher rate of glucose infusion to maintain euglycemia during hyperinsulinemic clamp studies and an attenuated hyperglycemic response to an ip glucose challenge. Regarding underlying mechanisms, we found that melatonin restored insulin-induced vasodilation to skeletal muscle, a major site of glucose utilization. This was due, at least in part, to the improvement of insulin signal transduction in the vasculature, as evidenced by increased insulin-induced phosphorylation of Akt and endoethelial nitric oxide synthase in aortas harvested from melatonin-treated high-fat diet-fed mice. In contrast, melatonin had no effect on the ability of insulin to promote glucose uptake in skeletal muscle tissue in vitro. These data demonstrate for the first time that in a diet-induced rodent model of insulin resistance, melatonin improves glucose homeostasis by restoring the vascular action of insulin.


Subject(s)
Endothelium, Vascular/drug effects , Glucose/metabolism , Insulin Resistance , Melatonin/pharmacology , Animals , Blood Flow Velocity/drug effects , Blood Pressure/drug effects , Deoxyglucose/pharmacokinetics , Dietary Fats/administration & dosage , Endothelium, Vascular/metabolism , Endothelium, Vascular/physiology , Glucose Tolerance Test , Heart Rate/drug effects , Homeostasis/drug effects , In Vitro Techniques , Insulin/blood , Male , Melatonin/administration & dosage , Mice , Mice, Inbred C57BL , Muscle, Skeletal/blood supply , Muscle, Skeletal/drug effects , Muscle, Skeletal/metabolism , Nitric Oxide Synthase Type III/metabolism , Phosphorylation/drug effects , Proto-Oncogene Proteins c-akt/metabolism
8.
Exp Cell Res ; 315(12): 2081-91, 2009 Jul 15.
Article in English | MEDLINE | ID: mdl-19328779

ABSTRACT

The specific sensitization of tumor cells to the apoptotic response induced by genotoxins is a promising way of increasing the efficacy of chemotherapies. The RasGAP-derived fragment N2, while not regulating apoptosis in normal cells, potently sensitizes tumor cells to cisplatin- and other genotoxin-induced cell death. Here we show that fragment N2 in living cells is mainly located in the cytoplasm and only minimally associated with specific organelles. The cytoplasmic localization of fragment N2 was required for its cisplatin-sensitization property because targeting it to the mitochondria or the ER abrogated its ability to increase the death of tumor cells in response to cisplatin. These results indicate that fragment N2 requires a spatially constrained cellular location to exert its anti-cancer activity.


Subject(s)
Apoptosis , Cell Nucleus/metabolism , Cytoplasm/metabolism , ras GTPase-Activating Proteins/metabolism , Amino Acid Motifs , Animals , Antineoplastic Agents/pharmacology , Cells, Cultured , Cisplatin/pharmacology , Humans , Mice , ras GTPase-Activating Proteins/genetics
9.
J Vasc Res ; 46(3): 188-98, 2009.
Article in English | MEDLINE | ID: mdl-18812700

ABSTRACT

Cx40-deficient mice (Cx40-/-) are hypertensive due to increased renin secretion. We evaluated the renal expression of neuronal nitric oxide synthase (nNOS) and cyclooxygenases COX-1 and COX-2, three macula densa enzymes. The levels of nNOS were increased in kidneys of Cx40-/- mice, as well as in those of wild-type (WT) mice subjected to the two-kidney one-clip model of hypertension. In contrast, the levels of COX-2 expression were only increased in the hypoperfused kidney of Cx40-/- mice. Treatment with indomethacin lowered blood pressure and renin mRNA in Cx40-/- mice without affecting renin levels, indicating that changes in COX-2 do not cause the altered secretion of renin. Suppression of NOS activity by N(G)-nitro-L-arginine methyl ester (L-NAME) decreased renin levels in Cx40-/- animals, indicating that NO regulates renin expression in the absence of Cx40. Treatment with candesartan normalized blood pressure in Cx40-/- mice, and decreased the levels of both COX-2 and nNOS. After a treatment combining candesartan and L-NAME, the blood pressure of Cx40-/- mice was higher than that of WT mice, showing that NO may counterbalance the vasoconstrictor effects of angiotensin II in Cx40-/- mice. These data document that renal COX-2 and nNOS are differentially regulated due to the elevation of renin-dependent blood pressure in mice lacking Cx40.


Subject(s)
Connexins/physiology , Cyclooxygenase 2/physiology , Hypertension/etiology , Kidney/enzymology , Nitric Oxide Synthase Type I/physiology , Animals , Blood Pressure/drug effects , Connexins/deficiency , Cyclooxygenase 2/analysis , Cyclooxygenase 2/genetics , Hypertension/enzymology , Mice , Mice, Inbred C57BL , Nitric Oxide Synthase Type I/analysis , Nitric Oxide Synthase Type I/genetics , Prostaglandin Antagonists/pharmacology , RNA, Messenger/analysis , Renin/blood , Gap Junction alpha-5 Protein
10.
J Physiol ; 586(16): 4011-6, 2008 Aug 15.
Article in English | MEDLINE | ID: mdl-18591189

ABSTRACT

Peroxynitrite synthesis is increased in insulin resistant animals and humans. Peroxynitirite-induced nitration of insulin signalling proteins impairs insulin action in vitro, but the role of peroxynitrite in the pathogenesis of insulin resistance in vivo is not known. We therefore assessed the effects of a 1-week treatment with the peroxynitrite decomposition catalyst FeTPPS on insulin sensitivity in insulin resistant high fat diet-fed (HFD) and control mice. FeTPPS normalized the fasting plasma glucose and insulin levels (P < 0.01), attenuated the hyperglycaemic response to an intraperitoneal glucose challenge by roughly 50% (P < 0.05), and more than doubled the insulin-induced decrease in plasma glucose levels in HFD-fed mice (P < 0.001). Moreover, FeTPPS restored insulin-stimulated Akt phosphorylation and insulin-stimulated glucose uptake in isolated skeletal muscle in vitro. Stimulation of peroxynitrite catalysis attenuates HFD-induced insulin resistance in mice by restoring insulin signalling and insulin-stimulated glucose uptake in skeletal muscle tissue.


Subject(s)
Blood Glucose/analysis , Dietary Fats/metabolism , Insulin Resistance/physiology , Metalloporphyrins/administration & dosage , Peroxynitrous Acid/metabolism , Animals , Catalysis/drug effects , Male , Mice , Mice, Inbred C57BL
11.
Angiology ; 59(4): 484-92, 2008.
Article in English | MEDLINE | ID: mdl-18388087

ABSTRACT

Metabolic syndrome is a constellation of major risk factors for cardiovascular disease. In affected individuals with this syndrome, the independent contribution of low high-density lipoprotein-cholesterol and increased triglyceride levels to the development of atherosclerosis remains to be clarified. We assessed the relationship between these 2 parameters and several surrogate markers for atherosclerosis. One hundred and twenty overweight cases, defined as having high-density lipoprotein-cholesterol (or=75 percentile) were compared with 120 discordant overweight controls defined on lipid values (high-density lipoprotein-cholesterol >or=50 percentile and triglycerides

Subject(s)
Atherosclerosis/etiology , Cholesterol, HDL/blood , Dyslipidemias/complications , Metabolic Syndrome/complications , Overweight/complications , Triglycerides/blood , Atherosclerosis/blood , Atherosclerosis/pathology , Atherosclerosis/physiopathology , Biomarkers/blood , Blood Pressure , Carotid Arteries/diagnostic imaging , Case-Control Studies , Dyslipidemias/blood , Dyslipidemias/pathology , Dyslipidemias/physiopathology , Endothelium, Vascular/diagnostic imaging , Endothelium, Vascular/physiopathology , Female , Femoral Artery/diagnostic imaging , Humans , Male , Metabolic Syndrome/blood , Metabolic Syndrome/pathology , Metabolic Syndrome/physiopathology , Middle Aged , Odds Ratio , Overweight/blood , Overweight/pathology , Overweight/physiopathology , Risk Assessment , Risk Factors , Skin/blood supply , Ultrasonography , Vasodilation
12.
Diabetes ; 56(11): 2690-6, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17682093

ABSTRACT

OBJECTIVE: Recent observations indicate that the delivery of nitric oxide by endothelial nitric oxide synthase (eNOS) is not only critical for metabolic homeostasis, but could also be important for mitochondrial biogenesis, a key organelle for free fatty acid (FFA) oxidation and energy production. Because mice deficient for the gene of eNOS (eNOS(-/-)) have increased triglycerides and FFA levels, in addition to hypertension and insulin resistance, we hypothesized that these knockout mice may have decreased energy expenditure and defective beta-oxidation. RESEARCH DESIGN AND METHODS: Several markers of mitochondrial activity were assessed in C57BL/6J wild-type or eNOS(-/-) mice including the energy expenditure and oxygen consumption by indirect calorimetry, in vitro beta-oxidation in isolated mitochondria from skeletal muscle, and expression of genes involved in fatty acid oxidation. RESULTS: eNOS(-/-) mice had markedly lower energy expenditure (-10%, P < 0.05) and oxygen consumption (-15%, P < 0.05) than control mice. This was associated with a roughly 30% decrease of the mitochondria content (P < 0.05) and, most importantly, with mitochondrial dysfunction, as evidenced by a markedly lower beta-oxidation of subsarcolemmal mitochondria in skeletal muscle (-30%, P < 0.05). Finally, impaired mitochondrial beta-oxidation was associated with a significant increase of the intramyocellular lipid content (30%, P < 0.05) in gastrocnemius muscle. CONCLUSIONS: These data indicate that elevated FFA and triglyceride in eNOS(-/-) mice result in defective mitochondrial beta-oxidation in muscle cells.


Subject(s)
Mitochondria/metabolism , Nitric Oxide Synthase Type III/deficiency , Animals , Body Size , Calorimetry, Indirect , DNA, Mitochondrial/genetics , Energy Metabolism , Epididymis/physiology , Fatty Acids, Nonesterified/metabolism , Lipolysis , Male , Mice , Mice, Knockout , Mitochondria, Muscle/physiology , Muscle, Skeletal/physiopathology , Nitric Oxide Synthase/metabolism , Nitric Oxide Synthase Type I/metabolism , Oxidation-Reduction , Oxygen Consumption , Polymerase Chain Reaction , Triglycerides/metabolism
13.
Am J Physiol Heart Circ Physiol ; 292(4): H1828-35, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17158645

ABSTRACT

The c-Jun NH(2)-terminal kinase (JNK) pathway of the mitogen-activated protein kinase (MAPK) signaling cascade regulates cell function and survival after stress stimulation. Equally robust studies reported dichotomous results suggesting both protective and detrimental effects of JNK during myocardial ischemia-reperfusion (I/R). The lack of a highly specific JNK inhibitor contributed to this controversy. We recently developed a cell-penetrating, protease-resistant peptide inhibitor of JNK, d-JNKI-1. Here we report on the effects of d-JNKI-1 in myocardial I/R. d-JNKI-1 was tested in isolated-perfused adult rat hearts. Increased activation of JNK, p38-MAPK, and extracellular signal-regulated kinase-1/2 (ERK1/2), as assessed by kinase assays and Western blotting, occurred during I/R. d-JNKI-1 delivered before onset of ischemia prevented the increase in JNK activity while not affecting ERK1/2 and p38-MAPK activation. JNK inhibition reduced ischemic injury, as manifested by increased time to contracture (P < 0.05) and decreased left ventricular end-diastolic pressure during ischemia (P < 0.01), and enhanced posthypoxic recovery of systolic and diastolic function (P < 0.01). d-JNKI-1 reduced mitochondrial cytochrome-c release, caspase-3 activation, and the number of apoptotic cells determined by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (P < 0.05), indicating suppression of the mitochondrial machinery of apoptosis. d-JNKI-1 delivered at the time of reperfusion did not improve functional recovery but still prevented apoptosis. In vivo, d-JNKI-1 reduced infarct size after coronary artery occlusion and reperfusion by approximately 50% (P < 0.01). In conclusion, d-JNKI-1 is an important compound that can be used in preclinical models to investigate the role of JNK signaling in vivo. Inhibition of JNK during I/R is cardioprotective in anesthetized rats in vivo.


Subject(s)
JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors , Myocardial Infarction/drug therapy , Myocardial Reperfusion Injury/drug therapy , Peptides/pharmacology , Animals , Apoptosis/drug effects , JNK Mitogen-Activated Protein Kinases/metabolism , MAP Kinase Signaling System/drug effects , Male , Myocardial Infarction/metabolism , Myocardial Reperfusion Injury/metabolism , Peptides/pharmacokinetics , Phosphorylation/drug effects , Rats , Rats, Sprague-Dawley , Recovery of Function/drug effects
14.
Genomics ; 89(3): 370-7, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17174066

ABSTRACT

Corticosteroids (aldosterone, cortisol/corticosterone) exert direct functional effects on cardiomyocytes. However, gene networks activated by corticosteroids in cardiomyocytes, as well as the involvement of the mineralocorticoid receptor (MR) vs the glucocorticoid receptor (GR) in these effects, remain largely unknown. Here we characterized the corticosteroid-dependent transcriptome in primary culture of neonatal mouse cardiomyocytes treated with 10(-6) M aldosterone, a concentration predicted to occupy both MR and GR. Serial analysis of gene expression revealed 101 aldosterone-regulated genes. The MR/GR specificity was characterized for one regulated transcript, namely ecto-ADP-ribosyltransferase-3 (Art3). Using cardiomyocytes from GR(null/null) or MR(null/null) mice we demonstrate that in GR(null/null) cardiomyocytes the response is abrogated, but it is fully maintained in MR(null/null) cardiomyocytes. We conclude that Art3 expression is regulated exclusively via the GR. Our study identifies a new set of corticosteroid-regulated genes in cardiomyocytes and demonstrates a new approach to studying the selectivity of MR- vs GR-dependent effects.


Subject(s)
Aldosterone/metabolism , Gene Expression Profiling , Gene Expression Regulation , Myocytes, Cardiac/metabolism , ADP Ribose Transferases/genetics , Animals , Animals, Newborn , Cells, Cultured , GPI-Linked Proteins , Mice , Mice, Inbred C57BL , Oligonucleotide Array Sequence Analysis , Receptors, Glucocorticoid/genetics , Receptors, Glucocorticoid/metabolism , Receptors, Mineralocorticoid/genetics , Receptors, Mineralocorticoid/metabolism , Transcription, Genetic
15.
Atherosclerosis ; 194(1): 253-64, 2007 Sep.
Article in English | MEDLINE | ID: mdl-16965774

ABSTRACT

BACKGROUND: Hypertension, hypercholesterolemia, obesity and smoking are highly prevalent among patients with familial premature coronary artery disease (FP-CAD). Whether these risk factors equally affect other family members remains unknown. METHODS: We examined 222 FP-CAD patients, 158 unaffected sibs, 197 offspring and 94 spouses in 108 FP-CAD families (> or = 2 sibs having survived CAD diagnosed before age 51 (M)/56 (F)), and compared them to population controls. RESULTS: Unaffected sibs had a higher prevalence of hypertension (49% versus 24%, p<0.001), hypercholesterolemia (47% versus 34%, p=0.002), abdominal obesity (35% versus 24%, p=0.006) and smoking (39% versus 24%, p=0.001) than population controls. Offspring had a higher prevalence of hypertension (females), hypercholesterolemia and abdominal obesity than population controls. No difference was observed between spouses and controls. Compared to unaffected sibs, FP-CAD affected sibs had a similar risk factor profile, except for smoking, which was more prevalent (76% versus 39%, p=0.008). CONCLUSIONS: Hypertension, obesity and hypercholesterolemia are highly prevalent among first-degree relatives, but not spouses, of patients with FP-CAD. These persons deserve special medical attention due to their familial/genetic susceptibility to atherogenic metabolic abnormalities. In these families, smoking may be the trigger for FP-CAD.


Subject(s)
Coronary Artery Disease/epidemiology , Coronary Artery Disease/genetics , Family , Abdominal Fat , Adult , Adult Children , Age of Onset , Body Mass Index , Female , Genetic Predisposition to Disease/epidemiology , Humans , Hypercholesterolemia/epidemiology , Hypercholesterolemia/genetics , Hypertension/epidemiology , Hypertension/genetics , Male , Middle Aged , Obesity/epidemiology , Obesity/genetics , Prevalence , Risk Factors , Siblings , Smoking/epidemiology , Smoking/genetics , Spouses/statistics & numerical data
16.
J Biomol Screen ; 11(8): 1015-26, 2006 Dec.
Article in English | MEDLINE | ID: mdl-17092917

ABSTRACT

Protein kinases are directly implicated in many human diseases; therefore, kinase inhibitors show great promises as new therapeutic drugs. In an effort to facilitate the screening and the characterization of kinase inhibitors, a novel application of the AlphaScreen technology was developed to monitor JNK activity from (1) purified kinase preparations and (2) endogenous kinase from cell lysates preactivated with different cytokines. The authors confirmed that both adenosine triphosphate (ATP) competitive as well as peptide-based JNK inhibitors were able to block the activity of both recombinant and HepG2 endogenous JNK activity. Using the same luminescence technique adapted for binding studies, the authors characterized peptide inhibitor mechanisms by measuring the binding affinity of the inhibitors for JNK. Because of the versatility of the technology, this cell-based JNK kinase assay could be adapted to other kinases and would represent a powerful tool to evaluate endogenous kinase activity and test a large number of potential inhibitors in a more physiologically relevant environment.


Subject(s)
Combinatorial Chemistry Techniques/methods , Drug Evaluation, Preclinical/methods , Enzyme Inhibitors/chemistry , Protein Kinases/metabolism , Binding Sites , Binding, Competitive , Cell Line , Dose-Response Relationship, Drug , Humans , MAP Kinase Kinase 4/metabolism
17.
Rev Med Suisse ; 1(17): 1126-30, 1132-3, 2005 Apr 27.
Article in French | MEDLINE | ID: mdl-15942999

ABSTRACT

Gap junctions are highly conserved structures that provide cells with a direct pathway for sharing ions, nutrients and other intracellular messengers, thus participating to the homeostasis of various tissues. Research on transgenic mice has revealed a major involvement of gap junctions proteins (connexins) in several cellular functions. At the same time, an increasing number of mutations of connexin genes has been linked to several hereditary diseases, including peripheral neuropathies, skin diseases, genetic deafness, cataracts and some forms of epilepsy. This review summarizes the state of knowledge about the implication of connexins in human pathologies.


Subject(s)
Connexins/physiology , Disease/etiology , Gap Junctions/physiology , Humans
18.
Rev Med Suisse ; 1(17): 1134-9, 2005 Apr 27.
Article in French | MEDLINE | ID: mdl-15943000

ABSTRACT

The emergence of multicellular organisms has necessitated the development of mechanisms for interactions between adjacent and distant cells. A consistent feature of this network is the expression of gap junction channels between the secretory cells of all glands so far investigated in vertebrates. Here, we reviewed the distribution of the gap junctions proteins, named connexins, in a few mammalian glands, and discussed the recent evidence pointing to the participation of these proteins in the functioning of endocrine and exocrine cells. Specifically, available data indicate the importance of gap junctions for the proper control of glucose-induced insulin secretion. Understanding the functions of beta-cell connexins are crucial for the engineering of surrogate cells, which is necessary for implementation of a replacement cell therapy in diabetic patients.


Subject(s)
Connexins/physiology , Endocrine System/metabolism , Gap Junctions/physiology , Animals , Humans , Islets of Langerhans/metabolism
19.
Crit Care Med ; 33(6): 1302-10, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15942348

ABSTRACT

OBJECTIVE: A distinctive feature of sepsis is a pleiotropic modification of membrane protein expression in the vascular endothelium, associated with diminished endothelium-dependent relaxation (endothelial dysfunction). In cultured endothelial cells, inflammatory stimuli alter expression of connexins (Cx), proteins that make up the gap junctions responsible for intercellular communication. In the present study, we tested whether the polymicrobial sepsis induced by cecal ligation and perforation in the rat alters the expression of the connexins present in the vascular endothelium (i.e., Cx37, Cx40, and Cx43). We also examined a possible association between such changes and endothelial dysfunction in this model. DESIGN: Animal study, with two parallel groups. SETTING: Animal research facility. SUBJECTS: One hundred four male adult Wistar rats. INTERVENTIONS: Rats underwent either cecal ligation and perforation to induce sepsis or a sham operation and were killed after a variable time, mostly 24 hrs. MEASUREMENTS AND MAIN RESULTS: Experiments designed to test for the impact of sepsis on connexin expression disclosed a three-fold increase in Cx40 messenger RNA and protein in the aorta, an effect that peaked at 24 hrs after cecal ligation and perforation, was specific to this connexin (i.e., levels of Cx37 and Cx43 did not vary), and was restricted to the aortic endothelium. Experiments designed to test the permeability of interendothelial gap junctions using the scrape-loading method did not show a change in function in the septic group. Finally, a time-course study was designed to test for a possible association of enhanced Cx40 expression with endothelial dysfunction. Endothelium-dependent relaxation was diminished in rings of aorta when harvested from septic rats before (6 hrs after surgery) but not at the time when enhanced Cx40 expression occurred (12 and 24 hrs). CONCLUSION: In this experimental model, recovery from an early transient dysfunction of the aortic endothelium is associated with an enhanced expression of aortic endothelial Cx40.


Subject(s)
Aorta/metabolism , Connexins/metabolism , Endothelium, Vascular/metabolism , Sepsis/physiopathology , Animals , Aorta/physiopathology , Connexin 43/metabolism , Endothelium, Vascular/physiopathology , Male , Multivariate Analysis , Rats , Rats, Wistar , Up-Regulation , Gap Junction alpha-5 Protein , Gap Junction alpha-4 Protein
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