4-hydroxy-2-nonenal and Hypertension

TRPA1 (transient receptor potential ankyrin 1), the lone member of the mammalian ankyrin TRP subfamily, is a Ca

Topics: Aldehydes; Animals; Calcitonin; Calcium; Calcium Channels; Cardiovascular System; Crotalus; Endothelial Cells; Gene Expression Regulation; Humans; Hypertension; Inflammation; Isothiocyanates; Molecular Conformation; Mustard Plant; Nerve Tissue Proteins; Plant Oils; Protein Conformation; Protein Domains; Stroke; Transient Receptor Potential Channels; TRPA1 Cation Channel; Vasodilation

Metabolic syndrome (MetS) is a predictor of cardiovascular diseases, commonly associated with oxidative stress and inflammation. However, the pathogenic mechanisms are not yet fully elucidated. The aim of the study is to evaluate the oxidative status and inflammation in the heart of obese Zucker rats (OZRs) and lean Zucker rats (LZRs) at different ages. Morphological and morphometric analyses were performed in the heart. To study the oxidative status, the malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), protein oxidation, and antioxidant enzymes were measured in plasma and heart. To elucidate the inflammatory markers involved, immunohistochemistry and Western blot were performed for cellular adhesion molecules and proinflammatory cytokines. OZRs were characterized by hypertension, hyperlipidemia, hyperglycemia, and insulin resistance. The obesity increased MDA and decreased the activities of superoxide dismutase (SOD) in plasma as well as in the heart, associated with cardiomyocytes hypertrophy. OxyBlot in plasma and in heart showed an increase of oxidativestate proteins in OZRs. Vascular cell adhesion molecule-1, interleukin-6, and tumor necrosis factor-α expressions in OZRs were higher than those of LZRs. However, these processes did not induce apoptosis or necrosis of cardiomyocytes. Thus, MetS induces the lipid peroxidation and decreased antioxidant defense that leads to heart tissue changes and coronary inflammation.

Topics: Aldehydes; Animals; Antioxidants; Cardiovascular System; Cytokines; Disease Models, Animal; Heart; Hyperglycemia; Hyperlipidemias; Hypertension; Inflammation; Insulin Resistance; Male; Malondialdehyde; Metabolic Syndrome; Obesity; Oxidative Stress; Rats; Rats, Zucker; Superoxide Dismutase

Reactive oxygen species (ROS) contribute to the dysfunction of serum lipoproteins, which triggers lipid metabolism abnormalities in the development of atherosclerosis and hypertension. Myeloperoxidase (MPO) is involved in ROS modifications, triggering lipid peroxidation and aldehyde formation. However, the relationship between the entirety of the MPO reaction system and oxidative modification of serum lipoproteins in atherosclerotic patients with hypertension remains unclear.. We measured MPO activity (peroxidation and chlorination), 4-hydroxynonenal-modified low-density lipoprotein (HNE-LDL), malondialdehyde-modified low-density lipoprotein (MDA-LDL), H2O2, reduced glutathione (GSH), and oxidized glutathione (GSSG) using a corresponding commercial kit in atherosclerotic patients with hypertension and healthy participants. We used Spearman's correlation analysis to investigate the correlation between MPO activity and the levels of these oxidative and anti-oxidative stress-related indices and performed response surface regression to investigate the relationship between the MPO reaction system and the levels of HNE-LDL, MDA-LDL, and the GSH/GSSG ratio.. Our results showed no association between the levels of MPO peroxidation activity, MPO chlorination activity, H2O2, and Cl- and those of HNE-LDL, MDA-LDL, GSH, and GSSG, and the GSH/GSSG ratio in healthy participants. In addition, no effects of the peroxidation reaction system of MPO (PRSM) and the chlorination reaction system of MPO (CRSM) on GSH/GSSG were found in this investigation. However, we found that the PRSM rather than the CRSM correlated with progressive low-density lipoprotein (LDL) modifications by HNE-LDL and MDA-LDL in atherosclerotic patients with hypertension.. The PRSM rather than the CRSM correlated with progressive LDL modifications via reactive aldehydes in atherosclerotic patients with hypertension. Further investigation is warranted to evaluate whether the PRSM may serve as a potential index for monitoring LDL function in atherosclerosis and hypertension.

Topics: Adult; Aged; Aldehydes; Atherosclerosis; Case-Control Studies; Female; Glutathione; Glutathione Disulfide; Halogenation; Humans; Hydrogen Peroxide; Hypertension; Lipid Peroxidation; Lipoproteins, LDL; Male; Middle Aged; Peroxidase

Subcortical white matter hyperintensities (WMH), presumed to indicate small vessel ischemic vascular disease, are found commonly in elderly individuals with and without Alzheimer's disease (AD). Oxidative stress may instigate or accelerate the development of vascular disease, and oxidative stress markers are elevated in AD. Here, we assess independent relationships between three serum lipid peroxidation markers (lipid hydroperoxides [LPH], 8-isoprostane, and 4-hydroxynonenal) and the presence of extensive subcortical WMH and/or AD. Patients were recruited from memory and stroke prevention clinics into four groups: minimal WMH, extensive WMH, AD with minimal WMH, and AD with extensive WMH. Extensive WMH, but not AD, was associated with higher serum concentrations of 8-isoprostane and LPH. Peripheral LPH concentrations mediated the effect of hypertension on deep, but not periventricular, WMH volumes. 4-hydroxynonenal was associated with hyperlipidemia and cerebral microbleeds, but not with extensive WMH or AD. We conclude that lipid peroxidation mediates hypertensive injury to the deep subcortical white matter and that peripheral blood lipid peroxidation markers indicate subcortical small vessel disease regardless of an AD diagnosis.

Topics: Aged; Aged, 80 and over; Aldehydes; Alzheimer Disease; Biomarkers; Cerebral Small Vessel Diseases; Cohort Studies; Cross-Sectional Studies; Dinoprost; Female; Humans; Hypertension; Lipid Peroxidation; Lipid Peroxides; Magnetic Resonance Imaging; Male; Middle Aged; Oxidative Stress; Risk Factors; White Matter

Angiotensin II (Ang II) and aldosterone contribute to hypertension, oxidative stress and cardiovascular damage, but the contributions of aldosterone during Ang II-dependent hypertension are not well defined because of the difficulty to assess each independently. To test the hypothesis that during Ang II infusion, oxidative and nitrosative damage is mediated through both the mineralocorticoid receptor (MR) and angiotensin type 1 receptor (AT1), five groups of Sprague-Dawley rats were studied: (i) control; (ii) Ang II infused (80 ng/min × 28 days); (iii) Ang II + AT1 receptor blocker (ARB; 10 mg losartan/kg per day × 21 days); (iv) Ang II + mineralocorticoid receptor (MR) antagonist (Epl; 100 mg eplerenone/day × 21 days); and (v) Ang II + ARB + Epl (Combo; × 21 days). Both ARB and combination treatments completely alleviated the Ang II-induced hypertension, whereas eplerenone treatment only prolonged the onset of the hypertension. Eplerenone treatment exacerbated the Ang II-mediated increase in plasma and heart aldosterone 2.3- and 1.8-fold, respectively, while ARB treatment reduced both. Chronic MR blockade was sufficient to ameliorate the AT1-mediated increase in oxidative damage. All treatments normalized protein oxidation (nitrotyrosine) levels; however, only ARB and Combo treatments completely reduced lipid peroxidation (4-hydroxynonenal) to control levels. Collectively, these data suggest that receptor signalling, and not the elevated arterial blood pressure, is the principal culprit in the oxidative stress-associated cardiovascular damage in Ang II-dependent hypertension.

Topics: Adrenal Glands; Aldehydes; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Biomarkers; Blood Pressure; Disease Models, Animal; Drug Therapy, Combination; Eplerenone; Heart Diseases; Hypertension; Lipid Peroxidation; Losartan; Male; Mineralocorticoid Receptor Antagonists; Myocardium; Oxidative Stress; Rats, Sprague-Dawley; Renin-Angiotensin System; Signal Transduction; Spironolactone; Time Factors; Tyrosine

As hypertension (HT) is one of the risk factors for lower urinary tract symptoms, we investigated the effect of an angiotensin II type I receptor blocker, olmesartan, on bladder dysfunction in the spontaneously hypertensive rat (SHR).. Twelve-week-old male SHRs were administered perorally with olmesartan (0, 1, or 3 mg/kg/day) or nifedipine (30 mg/kg/day) for 6 weeks. Wistar rats were used as normotensive controls. The effects of olmesartan or nifedipine on blood pressure (BP), bladder blood flow (BBF), urodynamic parameters, tissue levels of malondialdehyde (MDA), nuclear factor erythroid 2-related factor 2 (Nrf2), and nerve growth factor (NGF) were measured in the bladder. Localization of 4-hydroxy-2-nonenal (4-HNE), Nrf2, and NGF in the bladder was shown by immunohistochemistry.. The SHRs showed significant increase in BP, micturition frequency, and expression of MDA, 4-HNE, Nrf2, and NGF when compared to the control Wistar rats. Conversely, there was a decrease in BBF and single voided volume in SHRs when compared to Wistar rats. Treatment with olmesartan and nifedipine significantly improved BP. However, only olmesartan significantly ameliorated urodynamic parameters and oxidative damage compared to the non-treated SHR. The immunoreactivities of 4-HNE, Nrf2, and NGF in SHR urothelium and blood vessels were increased compared to the control. Treatment with a high dose of olmesartan decreased the expressions of 4-HNE, Nrf2, and NGF in the bladder.. Our data suggest that BP, BBF, and oxidative stress may be responsible for the functional changes in HT-related bladder dysfunction. Olmesartan significantly ameliorated this bladder dysfunction.

Topics: Aldehydes; Angiotensin II Type 1 Receptor Blockers; Animals; Antihypertensive Agents; Biomarkers; Blood Pressure; Disease Models, Animal; Hypertension; Imidazoles; Male; Malondialdehyde; Nerve Growth Factor; NF-E2-Related Factor 2; Nifedipine; Oxidative Stress; Rats; Rats, Inbred SHR; Rats, Wistar; Regional Blood Flow; Tetrazoles; Urinary Bladder; Urinary Bladder Diseases; Urodynamics

Telmisartan is an angiotensin receptor blocker with high lipid solubility, also called metabosartan, which exerts a special protective effect on both acute brain damage and chronic neurodegeneration. We examined the effects of telmisartan on oxidative stress by advanced glycation end product (AGE) and 4-hydroxynonenal (4-HNE) assays and the accumulation of phosphorylated α-synuclein (pSyn) in the brain of stroke-resistant spontaneously hypertensive rats (SHR-SR). At the age of 12 weeks, SHR-SR received transient middle cerebral artery occlusion (tMCAO) for 90 minutes and were divided into the following 3 groups: the vehicle group, the low-dose telmisartan group (.3 mg/kg/day), and the high-dose telmisartan group (3 mg/kg/day, postoperatively). Immunohistologic analysis was performed when rats were 6, 12, and 18 months old. AGE, 4-HNE, and pSyn-positive cells (per square millimeter) increased with age in the cerebral cortex and hippocampus of the vehicle group, in the low-dose telmisartan group, these parameters decreased without lowering blood pressure (BP), and in the high-dose telmisartan group, these parameters increased with lowering BP. The present study suggests that a persistent hypertension after tMCAO caused a progressive oxidative stress with the abnormal accumulation of pSyn, and that telmisartan reduced oxidative stress and the accumulation of pSyn without lowering BP (low dose) or improved these conditions with a reduction in BP (high dose) via its pleiotropic effects through a potential peroxisome proliferator-activated receptor gamma stimulation in the brain of SHR-SR.

Topics: Aldehydes; Angiotensin II Type 1 Receptor Blockers; Animals; Benzimidazoles; Benzoates; Blood Pressure; Brain; Glycation End Products, Advanced; Hypertension; Infarction, Middle Cerebral Artery; Male; Neuroprotective Agents; Oxidative Stress; Phosphorylation; Rats; Rats, Inbred SHR; Rats, Wistar; Synucleins; Telmisartan

Activation of tissue angiotensin II (Ang II) type 1 receptor (AT1R) plays an important role in the development of vascular remodelling. We have shown that the AT1R-associated protein (ATRAP/Agtrap), a specific binding protein of AT1R, functions as an endogenous inhibitor to prevent pathological activation of the tissue renin-angiotensin system. In this study, we investigated the effects of ATRAP on Ang II-induced vascular remodelling.. Transgenic (Tg) mice with a pattern of aortic vascular-dominant overexpression of ATRAP were obtained, and Ang II or vehicle was continuously infused into Tg and wild-type (Wt) mice via an osmotic minipump for 14 days. Although blood pressure of Ang II-infused Tg mice was comparable with that of Ang II-infused Wt mice, the Ang II-mediated development of aortic vascular hypertrophy was partially inhibited in Tg mice compared with Wt mice. In addition, Ang II-mediated up-regulation of vascular Nox4 and p22(phox), NADPH oxidase components, and 4-HNE, a marker of reactive oxygen species (ROS) generation, was significantly suppressed in Tg mice, with a concomitant inhibition of activation of aortic vascular p38MAPK and JNK by Ang II. This protection afforded by vascular ATRAP against Ang II-induced activation of NADPH oxidase is supported by in vitro experimental data using adenoviral transfer of recombinant ATRAP.. These results indicate that activation of aortic vascular ATRAP partially inhibits the Nox4/p22(phox)-ROS-p38MAPK/JNK pathway and pathological aortic hypertrophy provoked by Ang II-mediated hypertension, thereby suggesting ATRAP as a novel receptor-binding modulator of vascular pathophysiology.

Topics: Adaptor Proteins, Signal Transducing; Aldehydes; Angiotensin II; Animals; Aorta; Cells, Cultured; Cytochrome b Group; Disease Models, Animal; Hypertension; Hypertrophy; JNK Mitogen-Activated Protein Kinases; Mice; Mice, Inbred C57BL; Mice, Transgenic; NADPH Oxidase 4; NADPH Oxidases; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Rats, Sprague-Dawley; Reactive Oxygen Species; Signal Transduction; Time Factors; Transfection

The current study was designed to test the hypothesis that inducible nitric oxide synthase (iNOS)-mediated lipid free radical overproduction exists in an insulin-resistant rat model and that reducing the accumulation of toxic metabolites is associated with improved insulin signaling and metabolic response. Lipid radical formation was detected by electron paramagnetic resonance spectroscopy with in vivo spin trapping in an obese rat model, with or without thiazolidinedione treatment. Lipid radical formation was accompanied by accumulation of toxic end products in the liver, such as 4-hydroxynonenal and nitrotyrosine, and was inhibited by the administration of the selective iNOS inhibitor 1400 W. The model showed impaired phosphorylation of the insulin signaling pathway. Ten-day rosiglitazone injection not only improved the response to an oral glucose tolerance test and corrected insulin signaling but also decreased iNOS levels. Similar to the results with specific iNOS inhibition, thiazolidinedione dramatically decreased lipid radical formation. We demonstrate a novel mechanism where a thiazolidinedione treatment can reduce oxidative stress in this model through reducing iNOS-derived lipid radical formation. Our results suggest that hepatic iNOS expression may underlie the accumulation of lipid end products and that reducing the accumulation of toxic lipid metabolites contributes to a better redox status in insulin-sensitive tissues.

Topics: Aldehydes; Animals; Body Composition; Free Radicals; Glucose Intolerance; Heart Failure; Hypertension; Insulin Resistance; Lipid Peroxidation; Liver; Male; Muscle, Skeletal; Nitric Oxide Synthase Type II; Nitrites; Oxidative Stress; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Thiazolidinediones; Tyrosine

Mitochondria are a principal site for generation of reactive oxygen species (ROS) in the heart. Peroxisome proliferator activated receptor gamma coactivator 1 alpha (PGC-1 alpha) plays an important role in regulating mitochondrial biogenesis and myocardial metabolism, but whether PGC-1 alpha can simultaneously upregulate myocardial mitochondrial antioxidants has not been studied. In the present study, we examined the effect of PGC-1 alpha deficiency (PGC-1 alpha(-/-)) on oxidative stress and expression of a group of mitochondrial antioxidants in normal hearts and in hearts exposed to chronic systolic pressure overload produced by transverse aortic constriction (TAC). We found that PGC-1 alpha(-/-) caused moderate but significant decreases of myocardial mitochondrial antioxidant enzymes such as SOD2, and thioredoxin (Trx2), but had no effect on expression of myocardial oxidative stress markers and left ventricular (LV) function under basal conditions. However, in response to TAC for 6 weeks, PGC-1 alpha(-/-) mice showed greater increases of myocardial oxidative stress markers 3'-nitrotyrosine and 4-hydroxynonenal, more severe LV hypertrophy and dilatation, pulmonary congestion, and a greater reduction of LV fractional shortening and dP/dt(max) than did wild-type hearts. SOD mimetic MnTMPyP treatment (6 mg/kg/day) significantly attenuated TAC-induced LV hypertrophy and dysfunction in PGC-1 alpha(-/-) mice. These data indicate that PGC-1 alpha plays an important role in regulating expression of myocardial mitochondrial antioxidants SOD2 and Trx2 and in protecting hearts against TAC-induced myocardial oxidative stress, hypertrophy, and dysfunction.

Topics: Aldehydes; Animals; Antioxidants; Heart Failure; Hypertension; Hypertrophy, Left Ventricular; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondria, Heart; Myocardial Contraction; Myocardium; Nitroso Compounds; Oxidative Stress; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Reactive Oxygen Species; Superoxide Dismutase; Systole; Thioredoxins; Trans-Activators; Transcription Factors; Tyrosine

The purpose of this study is to elucidate the effect of wheel training on oxidative stress maker levels in spontaneous hypertensive rats (SHR). 4-hydroxynonenal and 3-nitrotyrosine levels in the aorta of SHRs were allowed to run for 10 weeks from the age of 15 weeks were measured and compared with those of nonexercised SHRs. The 4-hydroxynonenal and 3-nitrotyrosine levels in the exercised group were significantly lower than those in the nonexercised group. The exercised group showed a significant increase of manganese-containing superoxide dismutase. Endurance exercise showed a possible suppressing effect on the arteriosclerosis development by reducing oxidative stress, even after emergence of hypertension.

Topics: Age Factors; Aldehydes; Animals; Aorta; Blood Pressure; Coronary Artery Disease; Fluoroimmunoassay; Hypertension; Motor Activity; Nitric Oxide; Oxidative Stress; Physical Conditioning, Animal; Physical Endurance; Rats; Rats, Inbred SHR; Superoxide Dismutase; Superoxides; Tyrosine

Master regulators of protein synthesis such as mammalian target of rapamycin (mTOR) and p70S6 kinase contribute to left ventricular hypertrophy. These prohypertrophic pathways are modulated by a number of kinase cascades, including the hierarchical LKB1/AMP-activated protein kinase (AMPK) energy-sensing pathway. Because oxidative stress inhibits the LKB1/AMPK signaling axis to promote abnormal cell growth in cancer cells, we investigated whether oxidative stress associated with hypertension also results in the inhibition of this kinase circuit to contribute to left ventricular hypertrophy.. In the spontaneously hypertensive rat, a well-established genetic model of hypertension and subsequent cardiac hypertrophy, the development of left ventricular hypertrophy is associated with an increase in the electrophilic lipid peroxidation byproduct 4-hydroxy-2-nonenal (HNE). Using isolated cardiomyocytes, we show that elevated levels of HNE result in the formation of HNE-LKB1 adducts that inhibit LKB1 and subsequent AMPK activity. Consistent with inhibition of the LKB1/AMPK signaling pathway, the mTOR/p70S6 kinase system is activated, which is permissive for cardiac myocyte cell growth. Treatment of cardiomyocytes with resveratrol prevents HNE modification of the LKB1/AMPK signaling axis and blunts the prohypertrophic p70S6 kinase response. Furthermore, administration of resveratrol to spontaneously hypertensive rats results in increased AMPK phosphorylation and activity and reduced left ventricular hypertrophy.. Our data identify a molecular mechanism in the cardiomyocyte involving the oxidative stress-derived lipid peroxidation byproduct HNE and the LKB1/AMPK signaling pathway that contributes to the development of left ventricular hypertrophy. We also suggest that resveratrol may be a potential therapy for patients at risk for developing pathological cardiac hypertrophy by preventing this prohypertrophic process.

Topics: Aldehydes; AMP-Activated Protein Kinase Kinases; AMP-Activated Protein Kinases; Animals; Cardiomegaly; Cells, Cultured; Hypertension; Hypertrophy, Left Ventricular; Lipid Peroxidation; Myocytes, Cardiac; Oxidative Stress; Protein Kinases; Protein Serine-Threonine Kinases; Rats; Rats, Inbred SHR; Resveratrol; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Stilbenes; TOR Serine-Threonine Kinases

Beneficial effects of an antioxidant (N-acetyl-L-cysteine, NAC) and an angiotensin I-converting enzyme (ACE) inhibitor (ramipril) were assessed in a rat model of insulin resistance induced by 10% glucose feeding for 20 weeks. Treatments with NAC (2 g/kg per day) and ramipril (1 mg/kg per day) were initiated at 16 weeks in the drinking fluid. Systolic blood pressure, plasma levels of insulin and glucose, and insulin resistance were significantly higher in rats treated with glucose for 20 weeks. This was associated with a higher production of superoxide anion and NADPH oxidase activity in aorta and liver and with a marked reduction in protein expression of skeletal muscle insulin receptor substrate-1 (IRS-1) in the gastrocnemius muscle. NAC prevented all these alterations. Although ramipril also reversed high blood pressure, it had a lesser effect on insulin resistance (including IRS-1) and blocked superoxide anion production only in aorta. Ramipril, in contrast to NAC, did not reduce NADPH oxidase activity in aorta and liver or plasma levels of 4-hydroxynonenal and malondialdehyde. Results suggest that the inhibition of the oxidative stress in hypertensive and insulin-resistant states contributes to the therapeutic effects of NAC and ramipril. Whereas NAC exerts effective antioxidant activity in multiple tissues, ramipril appears to preferentially target the vasculature.

Topics: Acetylcysteine; Aldehydes; Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta, Thoracic; Blood Pressure; Diet; Free Radical Scavengers; Glucose; Hypertension; Insulin Receptor Substrate Proteins; Insulin Resistance; Lipid Peroxidation; Liver; Male; Malondialdehyde; Muscle, Skeletal; NADPH Oxidases; Oxidative Stress; Oxygen Consumption; Ramipril; Rats; Rats, Wistar

Oxidative stress is involved in the tolerance to ischemia-reperfusion (I/R) injury. Because angiotensin II type 1 receptor blockers (ARBs) inhibit oxidative stress, there is concern that ARBs abolish the tolerance to I/R injury. Dahl salt-sensitive (DS) hypertensive and salt-resistant (DR) normotensive rats received an antioxidant, 2-mercaptopropionylglycine (MPG), or an ARB, losartan, for 7 days. Losartan and MPG significantly inhibited oxidative stress as determined by tissue malondialdehyde + 4-hydroxynoneal and increased expression of inducible nitric oxide synthase (iNOS) in the DS rat heart. However, losartan but not MPG activated endothelial nitric oxide synthase (eNOS) as assessed by phosphorylation of eNOS on Ser1177. Infarct size after 30-min left coronary artery occlusion followed by 2-h reperfusion was comparable between DS and DR rat hearts. Although MPG and losartan had no effect on infarct size in the DR rat heart, MPG but not losartan significantly increased infarct size in the DS rat heart. A selective iNOS inhibitor, 1400W, increased infarct size in the DS rat heart, but it had no effect on infarct size in the losartan-treated DS rat heart. However, a nonselective NOS inhibitor, Nomega-nitro-l-arginine methyl ester, increased infarct size in the losartan-treated DS rat heart. These results suggest that losartan preserves the tolerance to I/R injury by activating eNOS despite elimination of redox-sensitive upregulation of iNOS and iNOS-dependent cardioprotection in the DS rat heart.

Topics: Aldehydes; Amidines; Angiotensin II Type 1 Receptor Blockers; Animals; Antioxidants; Benzylamines; Disease Models, Animal; Enzyme Activation; Enzyme Inhibitors; Hypertension; Losartan; Male; Malondialdehyde; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Oxidative Stress; Phosphorylation; Rats; Rats, Inbred Dahl; Sodium Chloride, Dietary; Tiopronin; Up-Regulation; Ventricular Function, Left

Accumulating evidence supports a role of 4-hydroxynonenal (4HNE) in oxidative-stress related diseases, but its specific contribution to disease development remains to be clarified. Further to our finding of high circulating 4HNE-protein thioether adducts (4HNE-P) in spontaneously hypertensive rats (SHRs), we aimed at correlating 4HNE-P with cardiac function and testing the impact of antioxidant therapy.. The lipoperoxidation inhibitor probucol (10 mg/kg/day) or vehicle (corn oil) were administered daily (i.p.) for 4 weeks in 18-week-old SHRs (9 rats/group). Cardiac functions were assessed by echocardiography and 4HNE-P by gas chromatography/mass spectrometry.. Diastolic dysfunction worsened in SHRs receiving vehicle as reflected by changes (P < 0.05) in indexes of left ventricular relaxation (increased isovolumic relaxation time) and compliance (increased E-wave deceleration rate; EDR). Higher circulating 4HNE-P correlated with diastolic dysfunction (EDR: R(2) = 0.518; P < 0.001) and heart rate (R(2) = 0.225; P < 0.05). Probucol prevented the deterioration of diastolic function, while lowering the mean and median of circulating 4HNE-P by 21% and 35%, respectively.. Collectively, these results support a role for 4HNE in the pathophysiological events linked to disease progression in SHRs.

Topics: Aldehydes; Animals; Antioxidants; Diastole; Electrocardiography; Heart Function Tests; Heart Rate; Hypertension; Lipid Peroxidation; Probucol; Rats; Rats, Inbred SHR

The hypertensive rat brain exhibited softening, severe edema and intracerebral hemorrhage. The NO(2) (-) + NO(3) (-) (NOx) level in the hypertensive rat brain was higher than in the normotensive rat brain. Light microscopy demonstrated severe arterial and arteriolar lesions with fibrinoid deposits and medial lesion. After injecting hypertensive rats with nitroblue tetrazolium (NBT), formazan deposits, which are the reaction product of reduction of NBT by superoxide, were observed in the microvessels and nervous tissue around the microvessels of injured brain. Immunohistochemistry showed that copper zinc superoxide dismutase and manganese superoxide dismutase expression of the endothelial cells of hypertensive rats were also upregulated in comparison with normotensive rat endothelial cells. Inducible nitric oxide synthase and endothelial nitric oxide synthase expression in endothelial cells of normotensive rats were strongly positive, whereas the expression in hypertensive rat endothelial cells was weaker. Nitrotyrosine, a biomarker of peroxynitrite, which is a powerful oxidant formed by the reaction of nitric oxide (NO) with superoxide, was found in the microvessels, injured arteries and arterioles and infarcted brain tissue. Deposition of a major aldehydic product of lipid peroxidation, that is, 4-hydroxy-2-nonenal (4-HNE) was found in microvessels, perivascular tissue, and edematous and infarcted brain. Hypertensive cerebrovascular disease is the result of hypertension-induced oxidative stress.

Topics: Aldehydes; Animals; Arterioles; Brain; Brain Edema; Cerebral Hemorrhage; Cerebrovascular Disorders; Disease Models, Animal; Endothelium, Vascular; Hypertension; Intracranial Arterial Diseases; Male; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Nitroblue Tetrazolium; Oxidative Stress; Rats; Rats, Wistar; Superoxide Dismutase; Tyrosine; Up-Regulation

High-dose administration of a steroid hormone has been associated with a major risk of osteonecrosis. In this study we investigated the effects of a steroid hormone on the incidence of osteonecrosis of the femoral head in stroke-prone spontaneously hypertensive rats/Nagasaki (SHRSP/Ngsks).. A total of 71 SHRSP/Ngsks were divided into two groups: a control group (C group, n = 40) and a steroid hormone group (S group, n = 31) given 5 mg (about 20 mg/kg) of methylprednisolone acetate during the 17th week of age. We compared the groups' laboratory data, histological appearance, incidence of osteonecrosis, and expression of oxidative stress on immunohistochemical analysis using the monoclonal antibodies anti-4HNE and anti-8OHdG.. The S group showed an increase in total cholesterol, with the amounts of high-density lipoprotein, low-density lipoprotein, and triglycerides all significantly higher than in the C group. Histological examination showed that the frequency of necrosis of the femoral head was significantly higher in the S group (95.2%) than in the C group (51.2%). Most of the histological features of the osteonecrosis demonstrated typical features of a similar sort in the two groups. However, the S group showed bone marrow spaces in the femoral head that were occupied by an increased number of adipocytes and that were swollen, partially degenerative, and necrotic. On immunohistochemical analysis, the stains of anti-4HNE and anti-8OHdG antibody were stronger in the S group than in the C group.. This study confirmed, to a remarkable degree, the suspicion that the administration of steroid hormone increases the number of adipocytes in marrow. Fat degeneration and necrosis, considered early signs of osteonecrosis, were also observed. It has been hypothesized that osteonecrosis is produced by the ischemic change accompanying compartment pressure load in marrow, where fat degeneration, necrosis, and endothelial cell injury might occur together with oxidative stress.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Antibodies, Monoclonal; Deoxyguanosine; Disease Models, Animal; DNA; Femur Head; Femur Head Necrosis; Glucocorticoids; Hypertension; Immunohistochemistry; Oxidative Stress; Rats; Rats, Inbred SHR; Risk Factors; Severity of Illness Index

Oxidative stress has been implicated in numerous degenerative diseases of aging, including heart diseases. However, there is still a need to identify biomarkers of oxidative stress-related events, such as protein modification by the lipid peroxidation product 4-hydroxynonenal (HNE) in these diseases in humans. The objective of this study was to assess if circulating levels of HNE-protein adducts (i) can be assessed with precision by GCMS and (ii) vary with disease progression and aging in a model of cardiomyopathy that displays enhanced oxidative stress, namely the spontaneously hypertensive rats (SHR). We modified a previously published isotope dilution GCMS method that quantifies HNE and its inactive metabolite, 1,4-dihydroxynonene (DHN), bound to thiol proteins following treatment with NaB(2)H(4) and Raney nickel, to increase its sensitivity (20-fold), precision, and robustness. Levels of these adducts were measured in blood and plasma collected from SHR and control Wistar rats at 7, 15, 22, and 30 weeks of age. Levels of protein-bound HNE, which were quantitated with good precision in the nanomolar range in blood, but not in plasma, were significantly increased by disease (SHR) and age (P < 0.0001 for both). Compared to Wistar rats, SHR showed greater blood levels of HNE-protein adducts at 22 and 30 weeks. Levels of protein-bound DHN, which were detected in blood and in plasma, were not affected by disease or age. Collectively, the results of this study conducted in an animal model of cardiomyopathy demonstrate that changes in blood HNE-protein thioether adducts with disease progression and aging can be assessed with good precision by the described GCMS method. This method may prove to be useful in evaluating the occurrence and impact of oxidative stress-related events involving bioactive HNE in heart diseases and aging in humans.

Topics: Aging; Aldehydes; Alkenes; Animals; Blood Proteins; Disease Progression; Gas Chromatography-Mass Spectrometry; Hypertension; Male; Rats; Rats, Inbred SHR; Rats, Wistar; Sulfides

Recent studies suggest that adipose tissue hormone, leptin, is involved in the pathogenesis of arterial hypertension. However, the mechanism of hypertensive effect of leptin is incompletely understood. We investigated whether antioxidant treatment could prevent leptin-induced hypertension. Hyperleptinemia was induced in male Wistar rats by administration of exogenous leptin (0.25 mg/kg twice daily s.c. for 7 days) and separate groups were simultaneously treated with superoxide scavenger, tempol, or NAD(P)H oxidase inhibitor, apocynin (2 mM in the drinking water). After 7 days, systolic blood pressure was 20.6% higher in leptin-treated than in control animals. Both tempol and apocynin prevented leptin-induced increase in blood pressure. Plasma concentration and urinary excretion of 8-isoprostanes increased in leptin-treated rats by 66.9% and 67.7%, respectively. The level of lipid peroxidation products, malonyldialdehyde + 4-hydroxyalkenals (MDA+4-HNE), was 60.3% higher in the renal cortex and 48.1% higher in the renal medulla of leptin-treated animals. Aconitase activity decreased in these regions of the kidney following leptin administration by 44.8% and 45.1%, respectively. Leptin increased nitrotyrosine concentration in plasma and renal tissue. Urinary excretion of nitric oxide metabolites (NO(x)) was 57.4% lower and cyclic GMP excretion was 32.0% lower in leptin-treated than in control group. Leptin decreased absolute and fractional sodium excretion by 44.5% and 44.7%, respectively. Co-treatment with either tempol or apocynin normalized 8-isoprostanes, MDA+4-HNE, aconitase activity, nitrotyrosine, as well as urinary excretion of NO(x), cGMP and sodium in rats receiving leptin. These results indicate that oxidative stress-induced NO deficiency is involved in the pathogenesis of leptin-induced hypertension.

Topics: Acetophenones; Aconitate Hydratase; Aldehydes; Animals; Antioxidants; Blood Pressure; Body Weight; Creatine; Cyclic GMP; Cyclic N-Oxides; Drinking; Eating; Hypertension; Isoprostanes; Kidney; Leptin; Male; Malondialdehyde; Natriuresis; Nitric Oxide; Rats; Rats, Wistar; Reactive Nitrogen Species; Sodium; Spin Labels; Tyrosine

We have investigated whether long-term administration of angiotensin (Ang) II causes ferritin induction and iron accumulation in the rat aorta, and their possible relation to regulatory effects on gene expression and vascular function in Ang II-infused animals.. Sprague-Dawley rats were given Ang II for 7 days via subcutaneously implanted osmotic minipumps. Ang II infusion caused a >20-fold increase in ferritin protein expression over control values. Immunohistochemistry showed that Ang II infusion markedly increased the ferritin expression in the aortic endothelial and adventitial cells, with some of the latter being identified as monocytes/macrophages. Prussian blue staining showed that stainable iron was observed in the adventitial layer of aorta from Ang II-infused animals, but not in the endothelial layer. Chelation of iron suppressed aortic induction of ferritin and also the oxidative stress markers, heme oxygenase-1 and 4-hydroxynonenal-modified protein adducts. In addition, iron chelation attenuated Ang II-induced impairment of aortic relaxations in response to acetylcholine and sodium nitroprusside and suppressed upregulation of mRNA levels of monocyte chemoattractant protein-1. Iron chelation also partially attenuated the medial thickening and perivascular fibrosis induced by Ang II infusion for 4 weeks.. Ang II infusion caused ferritin induction and iron deposition in the aortas. These phenomena might have a role in the regulation of gene expression, impairment of vascular function, and arterial remodeling induced by Ang II, which are presumably mediated in part by enhancement of oxidative stress.

Topics: Aldehydes; Angiotensin II; Animals; Aorta; Aortic Diseases; Apoferritins; Chemokine CCL2; Deferoxamine; Ferritins; Heme Oxygenase-1; Hypertension; Iron; Iron Chelating Agents; Iron Overload; Iron-Dextran Complex; Male; Norepinephrine; Oxidative Stress; Rats; Rats, Sprague-Dawley; Receptors, Transferrin; RNA, Messenger; Up-Regulation; Vasoconstrictor Agents; Vasodilation

Although NO derived from endothelial NO synthase (eNOS) is thought to be cardioprotective, the role of inducible NO synthase (iNOS) remains controversial. Using mice lacking iNOS (iNOS-/-), we studied (1) whether development of hypertension, cardiac hypertrophy, and dysfunction after deoxycorticosterone acetate (DOCA)-salt would be less severe compared with wild-type controls (WT; C57BL/6J), and (2) whether the cardioprotection attributable to lack of iNOS is mediated by reduced oxidative stress. Mice were uninephrectomized and received either DOCA-salt (30 mg/mouse SC and 1% NaCl+0.2% KCl in drinking water) or vehicle (tap water) for 12 weeks. Systolic blood pressure (SBP) was measured weekly. Left ventricular (LV) ejection fraction (EF) by echocardiography and cardiac response to isoproterenol (50 ng/mouse IV) were studied at the end of the experiment. Expression of eNOS and iNOS as well as the oxidative stress markers 4-hydroxy-2-nonenal (4-HNE, a marker of lipid peroxidation) and nitrotyrosine (a marker for peroxynitrite) were determined by Western blot and immunohistochemical staining, respectively. DOCA-salt increased SBP and LV weight similarly in both strains and decreased EF in WT but not in iNOS-/-. Cardiac contractile and relaxation responses to isoproterenol were greater, 4-HNE and nitrotyrosine levels were lower, and eNOS expression tended to be higher in iNOS-/-. We conclude that lack of iNOS leads to better preservation of cardiac function, which may be mediated by reduced oxidative stress and increased eNOS; however, it does not seem to play a significant role in preventing DOCA-salt-induced hypertension and hypertrophy.

Topics: Aldehydes; Animals; Blood Pressure; Cardiotonic Agents; Desoxycorticosterone; Heart; Hypertension; Hypertrophy, Left Ventricular; Isoproterenol; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardium; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Oxidative Stress; Sodium Chloride; Tyrosine

Mitochondrial dysfunction subsequent to increased oxidative stress and alterations in energy metabolism is considered to play a role in the development of cardiac hypertrophy and its progression to failure, although the sequence of events remains to be elucidated. This study aimed at characterizing the impact of hypertrophy development on the activity and expression of mitochondrial NADP+-isocitrate dehydrogenase (mNADP+-ICDH), a metabolic enzyme that controls redox and energy status. We expanded on our previous finding of its inactivation through posttranslational modification by the lipid peroxidation product 4-hydroxynonenal (HNE) in 7-wk-old spontaneously hypertensive rat (SHR) hearts before hypertrophy development (Benderdour et al. J Biol Chem 278: 45154-45159, 2003). In this study, we used 7-, 15-, and 30-wk-old SHR and Sprague-Dawley (SD) rats with abdominal aortic coarctation. Compared with age-matched control Wistar-Kyoto (WKY) rats, SHR hearts showed a significant 25% decrease of mNADP+-ICDH activity, which preceded in time 1) the decline in its protein and mRNA expression levels (between 10% and 35%) and 2) the increase in hypertrophy markers. The chronic and persistent loss of mNADP+-ICDH activity in SHR was associated with enhanced tissue accumulation of HNE-mNADP+-ICDH and total HNE-protein adducts at all ages and contrasted with the profile of changes in the activity of other mitochondrial enzymes involved in antioxidant or energy metabolism. Two-way ANOVA of the data also revealed a significant effect of age on most parameters measured in SHR and WKY hearts. The mNADP+-ICDH activity, protein, and mRNA expression were reduced between 25% and 35% in coarctated SD rats and were normalized by treatment of SHR or coarctated SD rats with renin-angiotensin system inhibitors, which prevented or attenuated hypertrophy. Altogether, our data show that cardiac mNADP+-ICDH activity and expression are differentially and sequentially affected in hypertrophy development and, to a lesser extent, with aging. Decreased cardiac mNADP+-ICDH activity, which is attributed at least in part to HNE adduct formation, appears to be a relevant early and persistent marker of mitochondrial oxidative stress-related alterations in hypertrophy development. Potentially, this could also contribute to the aetiology of cardiomyopathy.

Topics: Aldehydes; Angiotensin-Converting Enzyme Inhibitors; Animals; Aortic Coarctation; Biomarkers; Cardiomegaly; Enalapril; Hypertension; Isocitrate Dehydrogenase; Male; Mitochondria, Heart; NADP; Oxidative Stress; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renin-Angiotensin System; Superoxide Dismutase

4-Hydroxynonenal (HNE) degradation was investigated in isolated perfused rat hearts of the WKY and SHR strains before and after ischemia. HNE (10 mumoles l-1) were infused and the concentration of HNE in the effluent was determined. The rate of initial consumption was about 50 nmoles min-1 g-1 wet weight in hearts of both the WKY and SHR rats. In the WKY rat hearts, this rate of HNE degradation did not change during several minutes of HNE infusion and also remained constant during postischemic reperfusion. In the hearts of the SHR rats the HNE degradation rate declined within 5 min to 25 nmoles min-1 g-1 wet weight. Also during postischemic reperfusion, there was a lower HNE degradation rate in the SHR rat hearts than in the WKY rat hearts. The influence of hypertrophy on the rate of HNE degradation is discussed. It is suggested that the low degradation of the cytotoxic lipid peroxidation product, HNE, in hypertrophic hearts may contribute to reduced antioxidant defence in those hearts.

Topics: Aldehydes; Animals; Hypertension; In Vitro Techniques; Myocardial Reperfusion Injury; Myocardium; Rats; Rats, Inbred SHR; Rats, Inbred WKY