Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
Add more filters










Database
Language
Publication year range
1.
Hypertens Res ; 35(11): 1093-101, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22786567

ABSTRACT

Arteries from young healthy animals respond to chronic changes in blood flow and blood pressure by structural remodeling. We tested whether the ability to respond to decreased (-90%) or increased (+100%) blood flow is impaired during the development of deoxycorticosterone acetate (DOCA)-salt hypertension in rats, a model for an upregulated endothelin-1 system. Mesenteric small arteries (MrA) were exposed to low blood flow (LF) or high blood flow (HF) for 4 or 7 weeks. The bioavailability of vasoactive peptides was modified by chronic treatment of the rats with the dual neutral endopeptidase (NEP)/endothelin-converting enzyme (ECE) inhibitor SOL1. After 3 or 6 weeks of hypertension, the MrA showed hypertrophic arterial remodeling (3 weeks: media cross-sectional area (mCSA): 10±1 × 10(3) to 17±2 × 10(3) µm(2); 6 weeks: 13±2 × 10(3) to 24±3 × 10(3) µm(2)). After 3, but not 6, weeks of hypertension, the arterial diameter was increased (Ø: 385±13 to 463±14 µm). SOL1 reduced hypertrophy after 3 weeks of hypertension (mCSA: 6 × 10(3)±1 × 10(3) µm(2)). The diameter of the HF arteries of normotensive rats increased (Ø: 463±22 µm) but no expansion occurred in the HF arteries of hypertensive rats (Ø: 471±16 µm). MrA from SOL1-treated hypertensive rats did show a significant diameter increase (Ø: 419±13 to 475±16 µm). Arteries exposed to LF showed inward remodeling in normotensive and hypertensive rats (mean Ø between 235 and 290 µm), and infiltration of monocyte/macrophages. SOL1 treatment did not affect the arterial diameter of LF arteries but reduced the infiltration of monocyte/macrophages. We show for the first time that flow-induced remodeling is impaired during the development of DOCA-salt hypertension and that this can be prevented by chronic NEP/ECE inhibition.


Subject(s)
Blood Pressure/physiology , Desoxycorticosterone/adverse effects , Hypertension/pathology , Hypertension/physiopathology , Mesenteric Arteries/pathology , Mesenteric Arteries/physiopathology , Regional Blood Flow/physiology , Animals , Aspartic Acid Endopeptidases/antagonists & inhibitors , Aspartic Acid Endopeptidases/drug effects , Benzazepines/pharmacology , Blood Pressure/drug effects , Cell Movement/drug effects , Cell Movement/physiology , Disease Models, Animal , Endothelin-Converting Enzymes , Enzyme Inhibitors/pharmacology , Hypertension/chemically induced , Hypertrophy/chemically induced , Macrophages/pathology , Metalloendopeptidases/antagonists & inhibitors , Metalloendopeptidases/drug effects , Monocytes/pathology , Neprilysin/antagonists & inhibitors , Neprilysin/drug effects , Rats , Rats, Wistar , Regional Blood Flow/drug effects , Vascular Resistance/drug effects , Vascular Resistance/physiology
2.
PLoS One ; 6(7): e21817, 2011.
Article in English | MEDLINE | ID: mdl-21818267

ABSTRACT

BACKGROUND: Hypertension is, amongst others, characterized by endothelial dysfunction and vascular remodeling. As sphingolipids have been implicated in both the regulation of vascular contractility and growth, we investigated whether sphingolipid biology is altered in hypertension and whether this is reflected in altered vascular function. METHODS AND FINDINGS: In isolated carotid arteries from spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats, shifting the ceramide/S1P ratio towards ceramide dominance by administration of a sphingosine kinase inhibitor (dimethylsphingosine) or exogenous application of sphingomyelinase, induced marked endothelium-dependent contractions in SHR vessels (DMS: 1.4±0.4 and SMase: 2.1±0.1 mN/mm; n = 10), that were virtually absent in WKY vessels (DMS: 0.0±0.0 and SMase: 0.6±0.1 mN/mm; n = 9, p<0.05). Imaging mass spectrometry and immunohistochemistry indicated that these contractions were most likely mediated by ceramide and dependent on iPLA(2), cyclooxygenase-1 and thromboxane synthase. Expression levels of these enzymes were higher in SHR vessels. In concurrence, infusion of dimethylsphingosine caused a marked rise in blood pressure in anesthetized SHR (42±4%; n = 7), but not in WKY (-12±10%; n = 6). Lipidomics analysis by mass spectrometry, revealed elevated levels of ceramide in arterial tissue of SHR compared to WKY (691±42 vs. 419±27 pmol, n = 3-5 respectively, p<0.05). These pronounced alterations in SHR sphingolipid biology are also reflected in increased plasma ceramide levels (513±19 pmol WKY vs. 645±25 pmol SHR, n = 6-12, p<0.05). Interestingly, we observed similar increases in ceramide levels (correlating with hypertension grade) in plasma from humans with essential hypertension (185±8 pmol vs. 252±23 pmol; n = 18 normotensive vs. n = 19 hypertensive patients, p<0.05). CONCLUSIONS: Hypertension is associated with marked alterations in vascular sphingolipid biology such as elevated ceramide levels and signaling, that contribute to increased vascular tone.


Subject(s)
Ceramides/metabolism , Hypertension/metabolism , Adult , Anesthesia , Animals , Arachidonic Acid/metabolism , Blood Pressure/drug effects , Carotid Arteries/drug effects , Carotid Arteries/physiopathology , Ceramides/blood , Chromatography, Liquid , Coronary Vessels/drug effects , Coronary Vessels/physiopathology , Cyclooxygenase 1/metabolism , Female , Humans , Hypertension/blood , Hypertension/physiopathology , Immunohistochemistry , In Vitro Techniques , Male , Mass Spectrometry , Middle Aged , Phospholipases A2, Calcium-Independent/metabolism , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Sphingomyelin Phosphodiesterase/pharmacology , Sphingosine/administration & dosage , Sphingosine/pharmacology , Thromboxane A2/biosynthesis , Vasoconstriction/drug effects
3.
J Exp Med ; 204(5): 1227-35, 2007 May 14.
Article in English | MEDLINE | ID: mdl-17485520

ABSTRACT

The intercalated disc (ID) of cardiac myocytes is emerging as a crucial structure in the heart. Loss of ID proteins like N-cadherin causes lethal cardiac abnormalities, and mutations in ID proteins cause human cardiomyopathy. A comprehensive screen for novel mechanisms in failing hearts demonstrated that expression of the lysosomal integral membrane protein 2 (LIMP-2) is increased in cardiac hypertrophy and heart failure in both rat and human myocardium. Complete loss of LIMP-2 in genetically engineered mice did not affect cardiac development; however, these LIMP-2 null mice failed to mount a hypertrophic response to increased blood pressure but developed cardiomyopathy. Disturbed cadherin localization in these hearts suggested that LIMP-2 has important functions outside lysosomes. Indeed, we also find LIMP-2 in the ID, where it associates with cadherin. RNAi-mediated knockdown of LIMP-2 decreases the binding of phosphorylated beta-catenin to cadherin, whereas overexpression of LIMP-2 has the opposite effect. Collectively, our data show that LIMP-2 is crucial to mount the adaptive hypertrophic response to cardiac loading. We demonstrate a novel role for LIMP-2 as an important mediator of the ID.


Subject(s)
CD36 Antigens/metabolism , Cardiomyopathy, Dilated/metabolism , Hypertension/complications , Lysosomal Membrane Proteins/metabolism , Myocytes, Cardiac/metabolism , Animals , Aortic Valve Stenosis/metabolism , CD36 Antigens/genetics , Cadherins/metabolism , Cardiomyopathy, Dilated/etiology , Cardiomyopathy, Dilated/genetics , DNA Primers , Gene Expression Profiling , Gene Expression Regulation/physiology , Humans , Lysosomal Membrane Proteins/genetics , Mice , Mice, Knockout , Myocytes, Cardiac/pathology , RNA Interference , Rats , Rats, Sprague-Dawley , beta Catenin/metabolism
4.
BMC Bioinformatics ; 7: 200, 2006 Apr 11.
Article in English | MEDLINE | ID: mdl-16608515

ABSTRACT

BACKGROUND: Gene expression microarray technology permits the analysis of global gene expression profiles. The amount of sample needed limits the use of small excision biopsies and/or needle biopsies from human or animal tissues. Linear amplification techniques have been developed to increase the amount of sample derived cDNA. These amplified samples can be hybridised on microarrays. However, little information is available whether microarrays based on amplified and unamplified material yield comparable results. In the present study we compared microarray data obtained from amplified mRNA derived from biopsies of rat cardiac left ventricle and non-amplified mRNA derived from the same organ. Biopsies were linearly amplified to acquire enough material for a microarray experiment. Both amplified and unamplified samples were hybridized to the Rat Expression Set 230 Array of Affymetrix. RESULTS: Analysis of the microarray data showed that unamplified material of two different left ventricles had 99.6% identical gene expression. Gene expression patterns of two biopsies obtained from the same parental organ were 96.3% identical. Similarly, gene expression pattern of two biopsies from dissimilar organs were 92.8% identical to each other.Twenty-one percent of reporters called present in parental left ventricular tissue disappeared after amplification in the biopsies. Those reporters were predominantly seen in the low intensity range. Sequence analysis showed that reporters that disappeared after amplification had a GC-content of 53.7+/-4.0%, while reporters called present in biopsy- and whole LV-samples had an average GC content of 47.8+/-5.5% (P <0.001). Those reporters were also predicted to form significantly more (0.76+/-0.07 versus 0.38+/-0.1) and longer (9.4+/-0.3 versus 8.4+/-0.4) hairpins as compared to representative control reporters present before and after amplification. CONCLUSION: This study establishes that the gene expression profile obtained after amplification of mRNA of left ventricular biopsies is representative for the whole left ventricle of the rat heart. However, specific gene transcripts present in parental tissues were undetectable in the minute left ventricular biopsies. Transcripts that were lost due to the amplification process were not randomly distributed, but had higher GC-content and hairpins in the sequence and were mainly found in the lower intensity range which includes many transcription factors from specific signalling pathways.


Subject(s)
Artifacts , Gene Expression Profiling/methods , Heart Ventricles/metabolism , Nucleic Acid Amplification Techniques/methods , Oligonucleotide Array Sequence Analysis/methods , RNA, Messenger/genetics , Transcription Factors/genetics , Animals , Computer Simulation , Genes, Reporter , Models, Genetic , Models, Statistical , Rats , Reproducibility of Results , Sensitivity and Specificity
5.
Circ Res ; 95(5): 515-22, 2004 Sep 03.
Article in English | MEDLINE | ID: mdl-15284191

ABSTRACT

Cardiac hypertrophy can lead to heart failure (HF), but it is unpredictable which hypertrophied myocardium will progress to HF. We surmised that apart from hypertrophy-related genes, failure-related genes are expressed before the onset of failure, permitting molecular prediction of HF. Hearts from hypertensive homozygous renin-overexpressing (Ren-2) rats that had progressed to early HF were compared by microarray analysis to Ren-2 rats that had remained compensated. To identify which HF-related genes preceded failure, cardiac biopsy specimens were taken during compensated hypertrophy and we then monitored whether the rat progressed to HF or remained compensated. Among 48 genes overexpressed in failing hearts, we focused on thrombospondin-2 (TSP2). TSP2 was selectively overexpressed only in biopsy specimens from rats that later progressed to HF. Moreover, expression of TSP2 was increased in human hypertrophied hearts with decreased (0.19+/-0.01) versus normal ejection fraction (0.11+/-0.03 [arbitrary units]; P<0.05). Angiotensin II induced fatal cardiac rupture in 70% of TSP2 knockout mice, with cardiac failure in the surviving mice; this was not seen in wild-type mice. In TSP2 knockout mice, angiotensin II increased matrix metalloproteinase (MMP)-2 and MMP-9 activity by 120% and 390% compared with wild-type mice (P<0.05). In conclusion, we identify TSP2 as a crucial regulator of the integrity of the cardiac matrix that is necessary for the myocardium to cope with increased loading and that may function by its regulation of MMP activity. This suggests that expression of TSP2 marks an early-stage molecular program that is activated uniquely in hypertrophied hearts that are prone to fail.


Subject(s)
Cardiac Output, Low/etiology , Extracellular Matrix/metabolism , Hypertrophy, Left Ventricular/metabolism , Myocardium/metabolism , Thrombospondins/biosynthesis , Angiotensin II/antagonists & inhibitors , Angiotensin II/toxicity , Animals , Animals, Genetically Modified , Cardiac Output, Low/genetics , Cardiac Output, Low/metabolism , Cardiomyopathies/chemically induced , Collagenases/metabolism , Disease Progression , Enzyme Precursors/metabolism , Gelatinases/metabolism , Gene Expression , Gene Expression Profiling , Genetic Predisposition to Disease , Heart Rupture/chemically induced , Heart Rupture/pathology , Humans , Hypertension/complications , Hypertrophy, Left Ventricular/complications , Hypertrophy, Left Ventricular/genetics , Matrix Metalloproteinase 9 , Metalloendopeptidases/metabolism , Mice , Mice, Knockout , Myocardium/pathology , Rats , Rats, Sprague-Dawley , Renin/genetics , Stroke Volume , Thrombospondins/genetics , Thrombospondins/physiology , Up-Regulation
6.
Exp Physiol ; 89(5): 605-15, 2004 Sep.
Article in English | MEDLINE | ID: mdl-15258119

ABSTRACT

The short-term (<24 h) consequences of oxidative stress induced by ischaemia-reperfusion (IR) have been studied extensively in the mouse heart. However, much less is known about the long-term effects inflicted by a brief ischaemic period on the murine heart. We therefore examined the structural and functional consequences of a 30 min ischaemic period after 2 and 8 weeks of reperfusion and compared these to the effects induced by permanent occlusion of the left anterior descending coronary artery (LAD). The latter procedure resulted in transmural myocardial infarcts of about 52% of the left ventricle. In contrast, the single 30 min ischaemic period led to infarct sizes of about 13% of the left ventricle (range, 4-23%) at 2 and 8 weeks after reperfusion. Maximal cardiac contractility responses (+dP/dt) to dobutamine infusion and volume loading were depressed at 2, but not at 8 weeks after IR. The restoration of cardiac contractility at 8 weeks after IR was associated with a significant 20% enlargement of the end-diastolic volume and 16% increase of the left ventricular wall thickness. These changes in cardiac geometry were less pronounced at 2 weeks after IR. Histological examination revealed that the IR injury was associated with prominent calcification. At 2 and at 8 weeks after IR, 25 +/- 5 and 38 +/- 5% of the injured area was calcified as observed in 69 and 73% of the animals, respectively. After permanent occlusion of the LAD, calcification was not observed and healing of the affected area was characterized by thinning and dilatation of the infarcted myocardium. These data indicate that, in mice, a single 30 min period of ischaemia reduced ventricular contractility up to at least 2 weeks after reperfusion. However, 8 weeks after IR, cardiac function was restored by eccentric hypertrophy associated with calcification of the injured ventricular wall.


Subject(s)
Myocardial Reperfusion Injury/pathology , Ventricular Function, Left/physiology , Animals , Male , Mice , Myocardial Contraction/physiology , Myocardial Reperfusion Injury/diagnostic imaging , Time , Ultrasonography
7.
Am J Physiol Heart Circ Physiol ; 287(4): H1618-24, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15155266

ABSTRACT

The aim of this study was to compare the systemic hemodynamic effects of four commonly used anesthetic regimens in mice that were chronically instrumented for direct and continuous measurements of cardiac output (CO). Mice (CD-1, Swiss, and C57BL6 strains) were instrumented with a transit-time flow probe placed around the ascending aorta for CO measurement. An arterial catheter was inserted into the aorta 4 or 5 days later for blood pressure measurements. After full recovery, hemodynamic parameters including stroke volume, heart rate, CO, mean arterial pressure (MAP), and total peripheral resistance were measured with animals in the conscious state. General anesthesia was then induced in these mice using isoflurane (Iso), urethane, pentobarbital sodium, or ketamine-xylazine (K-X). The doses and routes of administration of these agents were given as required for general surgical procedures in these animals. Compared with the values obtained for animals in the conscious resting state, MAP and CO decreased during all anesthetic interventions, and hemodynamic effects were smallest for Iso (MAP, -24 +/- 3%; CO, -5 +/- 7%; n = 15 mice) and greatest for K-X (MAP, -51 +/- 6%; CO, -37 +/- 9%; n = 8 mice), respectively. The hemodynamic effects of K-X were fully antagonized by administration of the alpha(2)-receptor antagonist atipamezole (n = 8 mice). These results indicate that the anesthetic Iso has fewer systemic hemodynamic effects in mice than the nonvolatile anesthetics.


Subject(s)
Anesthetics, Inhalation/pharmacology , Blood Pressure/drug effects , Cardiac Output/drug effects , Isoflurane/pharmacology , Adjuvants, Anesthesia/pharmacology , Adrenergic alpha-Agonists/pharmacology , Adrenergic alpha-Antagonists/pharmacology , Analgesics, Opioid/pharmacology , Anesthetics, Dissociative/pharmacology , Anesthetics, Intravenous/pharmacology , Animals , Buprenorphine/pharmacology , Female , Imidazoles/pharmacology , Ketamine/pharmacology , Male , Mice , Mice, Inbred C57BL , Pentobarbital/pharmacology , Urethane/pharmacology , Xylazine/pharmacology
SELECTION OF CITATIONS
SEARCH DETAIL
...