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1.
Hypertension ; 74(2): 295-304, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31291149

RESUMO

Subendocardial damage is among the first cardiac manifestations of hypertension and is already present in asymptomatic disease states. Accordingly, markers of subendocardial impairment may facilitate early detection of cardiac damages and risk stratification under these conditions. This study aimed to investigate the impact of subendocardial damage on myocardial microstructure and function to elucidate early pathophysiologic processes and to identify corresponding diagnostic measures. Mice (n=38) were injected with isoproterenol to induce isolated subendocardial scarring or saline as corresponding control. Cardiac function and myocardial deformation were determined by high-frequency echocardiography. The cardiac stress response was assessed in a graded exercise test and during dobutamine stress echocardiography. Myocardial microstructure was studied ex vivo by 7 T diffusion tensor magnetic resonance imaging at a spatial resolution of 100×100×100 µm 3 . Results were correlated with histology and biomarker expression. Subendocardial fibrosis was accompanied by diastolic dysfunction, impaired longitudinal deformation (global peak longitudinal strain [LS]: -12.5±0.5% versus -15.6±0.5%; P<0.001) and elevated biomarker expression (ANP [atrial natriuretic peptide], Galectin-3, and ST2). Systolic function and cardiac stress response remained preserved. Diffusion tensor magnetic resonance imaging revealed a left-shift in helix angle towards lower values in isoproterenol-treated animals, which was mainly determined by subepicardial myofibers (mean helix angle: 2.2±0.8° versus 5.9±1.0°; P<0.01). Longitudinal strain and subepicardial helix angle were highly predictive for subendocardial fibrosis (sensitivity, 82%-92% and specificity, 89%-90%). The results indicate that circumscribed subendocardial damage alone can cause several hallmarks observed in cardiovascular high-risk patients. Microstructural remodeling under these conditions involves also remote regions, and corresponding changes in longitudinal strain and helix angle might serve as diagnostic markers.

2.
Cardiovasc Ultrasound ; 17(1): 7, 2019 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-31010431

RESUMO

Echocardiography is the most commonly applied technique for non-invasive assessment of cardiac function in small animals. Manual tracing of endocardial borders is time consuming and varies with operator experience. Therefore, we aimed to evaluate a novel automated two-dimensional software algorithm (Auto2DE) for small animals and compare it to the standard use of manual 2D-echocardiographic assessment (2DE). We hypothesized that novel Auto2DE will provide rapid and robust data sets, which are in agreement with manually assessed data of animals.2DE and Auto2DE were carried out using a high-resolution imaging-system for small animals. First, validation cohorts of mouse and rat cine loops were used to compare Auto2DE against 2DE. These data were stratified for image quality by a blinded expert in small animal imaging. Second, we evaluated 2DE and Auto2DE in four mouse models and four rat models with different cardiac pathologies.Automated assessment of LV function by 2DE was faster than conventional 2DE analysis and independent of operator experience levels. The accuracy of Auto2DE-assessed data in healthy mice was dependent on cine loop quality, with excellent agreement between Auto2DE and 2DE in cine loops with adequate quality. Auto2DE allowed for valid detection of impaired cardiac function in animal models with pronounced cardiac phenotypes, but yielded poor performance in diabetic animal models independent of image quality.Auto2DE represents a novel automated analysis tool for rapid assessment of LV function, which is suitable for data acquisition in studies with good and very good echocardiographic image quality, but presents systematic problems in specific pathologies.

4.
Basic Res Cardiol ; 113(6): 45, 2018 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-30338362

RESUMO

Sterile inflammation of visceral fat, provoked by dying adipocytes, links the metabolic syndrome to cardiovascular disease. Danger-associated molecular patterns, such as adenosine triphosphate (ATP), are released by activated or dying cells and orchestrate leukocyte infiltration and inflammation via the purinergic receptor P2Y2. The gene expression of ATP receptor P2Y2 did not change in several tissues in the course of obesity, but was increased within epididymal fat. Adipose tissue from P2Y 2 -/- mice consuming high-fat diet (HFD) contained less crown-like structures with a reduced frequency of adipose tissue macrophages (ATMs). This was likely due to decreased leukocyte migration because of missing VCAM-1 exposition on P2Y2 deficient hypertrophic adipose tissue endothelial cells. Accordingly, P2Y 2 -/- mice showed blunted traits of the metabolic syndrome: they gained less weight compared to P2Y 2 +/+ controls, while intake of food and movement behaviour remained unchanged. Liver and adipose tissue were smaller in P2Y 2 -/- animals. Insulin tolerance testing (ITT) performed in obese P2Y 2 -/- mice revealed a better insulin sensitivity as well as lower plasma C-peptide and cholesterol levels. We demonstrate that interfering with somatic P2Y2 signalling prevents excessive immune cell deposition in diet-induced obesity (DIO), both attenuating adipose tissue inflammation and ameliorating the metabolic phenotype. Thus, blocking the P2Y2 cascade may be a promising strategy to limit metabolic disease and its sequelae.

6.
Hypertension ; 72(3): e20-e29, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29987108

RESUMO

The effects of the selective AT2R (angiotensin AT2 receptor) agonist, Compound 21 (C21), on abdominal aortic aneurysm formation were investigated in normotensive Wistar rats. Abdominal aortic aneurysm was induced by perfusion of isolated aortic segments with elastase. Treatment with C21 (0.03 mg/kg daily) was started after operation and continued for 14 days. Sham-operated animals and vehicle-treated animals after aneurysm induction served as controls. Aortic diameter, aortic wall distensibility, and pulse propagation velocity were measured via ultrasound. Hemodynamic parameters, aortic tissue protein expression, and serum cytokines were analyzed. On day 14 post aneurysm induction, aortic diameter of vehicle-treated animals was increased 1.6-fold compared with sham-operated rats (2.65±0.05 versus 1.70±0.06 mm; P<0.0001). C21 decreased aortic diameter in comparison to vehicle (1.9±0.06 versus 2.65±0.05; P<0.0001). Infrarenal blood velocity and aortic distensibility were reduced, whereas aortic wall stiffness was increased post aneurysm induction. These alterations were significantly ameliorated by treatment with C21 while blood pressure and cardiac contractility remained unchanged. Protein expression of IL-1ß (interleukin-1ß), NFκB (nuclear factor κB), MMP9 (matrix metalloproteinase 9), TGF-ß1 (transforming growth factor-ß1), and MLKL (mixed lineage kinase domain-like) in the aorta was significantly ( P<0.05) down-regulated in the C21 group compared with vehicle. Serum concentration of TGF-ß1 was decreased by C21 in comparison to vehicle ( P<0.01). AT2R stimulation with C21 prevented extracellular matrix degradation, maintained vascular integrity of the aorta and prevented abdominal aortic aneurysm progression.

7.
Cardiovasc Ultrasound ; 16(1): 10, 2018 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-29966517

RESUMO

BACKGROUND: The assessment of ventricular volumes using conventional echocardiography methods is limited with regards to the need of geometrical assumptions. In the present study, we aimed to evaluate a novel commercial system for three-dimensional echocardiography (3DE) in preclinical models by direct comparison with conventional 1D- and 2D-echocardiography (1DE; 2DE) and the gold-standard technique magnetic resonance imaging (MRI). Further, we provide a standard operating protocol for image acquisition and analysis with 3DE. METHODS: 3DE was carried out using a 30 MHz center frequency transducer coupled to a Vevo®3100 Imaging System. We evaluated under different experimental conditions: 1) in vitro phantom measurements served as controlled setting in which boundaries were clearly delineated; 2) a validation cohort composed of healthy C57BL/6 J mice and New Zealand Obese (NZO) mice was used in order to validate 3DE against cardiac MRI; 3) a standard mouse model of pressure overload induced-heart failure was investigated to estimate the value of 3DE. RESULTS: First, in vitro volumetry revealed good agreement between 3DE assessed volumes and the MRI-assessed volumes. Second, cardiac volume determination with 3DE showed smaller mean differences compared to cardiac MRI than conventional 1DE and 2DE. Third, 3DE was suitable to detect reduced ejection fractions in heart failure mice. Fourth, inter- and intra-observer variability of 3DE showed good to excellent agreement regarding absolute volumes in healthy mice, whereas agreement rates for the relative metrics ejection fraction and stroke volume demonstrated good to moderate observer variabilities. CONCLUSIONS: 3DE provides a novel method for accurate volumetry in small animals without the need for spatial assumptions, demonstrating a technique for an improved analysis of ventricular function. Further validation work and highly standardized image analyses are required to increase reproducibility of this approach.


Assuntos
Ecocardiografia Tridimensional , Insuficiência Cardíaca/diagnóstico por imagem , Volume Sistólico , Animais , Modelos Animais de Doenças , Ecocardiografia , Interpretação de Imagem Assistida por Computador , Processamento de Imagem Assistida por Computador , Imagem por Ressonância Magnética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Variações Dependentes do Observador , Reprodutibilidade dos Testes
8.
Exp Neurol ; 306: 34-44, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29684438

RESUMO

Evidence for a critical pathophysiological role of aberrant cytoskeletal dynamics is being uncovered in a growing number of neuropsychiatric syndromes. A sedentary lifestyle as well as overt psychopathology is prevalent in patients with the metabolic syndrome. Using mice deficient in gelsolin (Gsn-/-), a crucial actin-severing protein, we here investigated reduced actin turnover as a potential common driver of metabolic disturbances, sedentary behavior, and an anxious/depressive phenotype. Gelsolin deficiency resulted in reduced lifespan. As compared to wildtype controls, Gsn-/- mice (~ 9 weeks) fed a high-fat diet (HFD) over a span of 12 weeks showed increased body weight gain, fat mass, hepatic steatosis, and adipocyte hypertrophy as well as a significantly reduced respiratory quotient. Moreover, increased rigidity of the actin cytoskeleton in mice on HFD induced mRNA expression of Acc1, Acc2, Fasn, and Lipe, key genes involved in fatty acid metabolism in the liver. Glucose tolerance and insulin sensitivity were worsened in Gsn-/- HFD relative to Gsn+/+ HFD mice. Hypertension in Gsn-/- mice was associated with reduced endothelial NO synthase (eNOS) mRNA expression and reduced eNOS protein trafficking to the plasma membrane. Furthermore, acetylcholine-induced cGMP production and relaxation of aortic rings were impaired by actin filament stabilization. Gsn-/- mice on HFD displayed reduced corticosterone concentrations and reduced energy expenditure as compared to Gsn+/+ HFD mice. Moreover, Gsn-/- HFD mice displayed an overall pattern of hypoactive and anxious/depressive-like behavior. In aggregate, our results demonstrate that impaired actin filament dynamics promote the development of key behavioral and physiological aspects of the metabolic syndrome.

9.
Hypertension ; 71(4): 599-608, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29437893

RESUMO

Mineralocorticoid receptor antagonists (MRAs) reduce morbidity and mortality in chronic heart failure. Novel nonsteroidal MRAs are currently developed and need to be pharmacologically characterized in comparison to classical steroidal MRAs. A mouse model of cardiac fibrosis induced by short-term isoproterenol injection was used to compare the nonsteroidal MRA finerenone and the steroidal MRA eplerenone in equi-efficient systemic MR blocking dosages. Molecular mechanisms were studied in MR-expressing H9C2/MR+ cardiomyocytes and in MR transcriptional cofactor binding assays. Both MRAs significantly inhibited an isoproterenol-mediated increase of left ventricular mass. Isoproterenol-induced cardiac fibrosis and macrophage invasion were potently blocked by finerenone, whereas eplerenone had no significant effect. Speckle tracking echocardiography revealed a significant improvement of global longitudinal peak strain by finerenone, an effect less prominent with eplerenone. Antifibrotic actions of finerenone were accompanied by a significant inhibition of profibrotic cardiac TNX (tenascin-X) expression, a regulation absent with eplerenone. Finally, we show a higher potency/efficacy and inverse agonism of finerenone versus eplerenone in MR transcriptional cofactor binding assays indicating differential MR cofactor modulation by steroidal and nonsteroidal MRAs. This study demonstrates that the nonsteroidal MRA finerenone potently prevents cardiac fibrosis and improves strain parameters in mice. Cardiac antifibrotic actions of finerenone may result from the inhibition of profibrotic TNX gene expression mediated by differential MR cofactor binding. Selective MR cofactor modulation provides a molecular basis for distinct (pre)-clinical actions of nonsteroidal and steroidal MRAs.

10.
Circ Res ; 122(5): 693-700, 2018 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-29358227

RESUMO

RATIONALE: The coincidence of inflammation and metabolic derangements in obese adipose tissue has sparked the concept of met-inflammation. Previous observations, however, suggest that inflammatory pathways may not ultimately cause dysmetabolism. OBJECTIVE: We have revisited the relationship between inflammation and metabolism by testing the role of TRAF (tumor necrosis receptor-associated factor)-1, an inhibitory adapter of inflammatory signaling of TNF (tumor necrosis factor)-α, IL (interleukin)-1ß, and TLRs (toll-like receptors). METHODS AND RESULTS: Mice deficient for TRAF-1, which is expressed in obese adipocytes and adipose tissue lymphocytes, caused an expected hyperinflammatory phenotype in adipose tissue with enhanced adipokine and chemokine expression, increased leukocyte accumulation, and potentiated proinflammatory signaling in macrophages and adipocytes in a mouse model of diet-induced obesity. Unexpectedly, TRAF-1-/- mice were protected from metabolic derangements and adipocyte growth, failed to gain weight, and showed improved insulin resistance-an effect caused by increased lipid breakdown in adipocytes and UCP (uncoupling protein)-1-enabled thermogenesis. TRAF-1-dependent catabolic and proinflammatory cues were synergistically driven by ß3-adrenergic and inflammatory signaling and required the presence of both TRAF-1-deficient adipocytes and macrophages. In human obesity, TRAF-1-dependent genes were upregulated. CONCLUSIONS: Enhancing TRAF-1-dependent inflammatory pathways in a gain-of-function approach protected from metabolic derangements in diet-induced obesity. These findings identify TRAF-1 as a regulator of dysmetabolism in mice and humans and question the pathogenic role of chronic inflammation in metabolism.

11.
PLoS Genet ; 14(1): e1007171, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29320510

RESUMO

Adipose tissue lipolysis occurs during the development of heart failure as a consequence of chronic adrenergic stimulation. However, the impact of enhanced adipose triacylglycerol hydrolysis mediated by adipose triglyceride lipase (ATGL) on cardiac function is unclear. To investigate the role of adipose tissue lipolysis during heart failure, we generated mice with tissue-specific deletion of ATGL (atATGL-KO). atATGL-KO mice were subjected to transverse aortic constriction (TAC) to induce pressure-mediated cardiac failure. The cardiac mouse lipidome and the human plasma lipidome from healthy controls (n = 10) and patients with systolic heart failure (HFrEF, n = 13) were analyzed by MS-based shotgun lipidomics. TAC-induced increases in left ventricular mass (LVM) and diastolic LV inner diameter were significantly attenuated in atATGL-KO mice compared to wild type (wt) -mice. More importantly, atATGL-KO mice were protected against TAC-induced systolic LV failure. Perturbation of lipolysis in the adipose tissue of atATGL-KO mice resulted in the prevention of the major cardiac lipidome changes observed after TAC in wt-mice. Profound changes occurred in the lipid class of phosphatidylethanolamines (PE) in which multiple PE-species were markedly induced in failing wt-hearts, which was attenuated in atATGL-KO hearts. Moreover, selected heart failure-induced PE species in mouse hearts were also induced in plasma samples from patients with chronic heart failure. TAC-induced cardiac PE induction resulted in decreased PC/ PE-species ratios associated with increased apoptotic marker expression in failing wt-hearts, a process absent in atATGL-KO hearts. Perturbation of adipose tissue lipolysis by ATGL-deficiency ameliorated pressure-induced heart failure and the potentially deleterious cardiac lipidome changes that accompany this pathological process, namely the induction of specific PE species. Non-cardiac ATGL-mediated modulation of the cardiac lipidome may play an important role in the pathogenesis of chronic heart failure.


Assuntos
Tecido Adiposo/metabolismo , Insuficiência Cardíaca/etiologia , Hipertensão/complicações , Lipase/fisiologia , Metabolismo dos Lipídeos/genética , Miocárdio/metabolismo , Disfunção Ventricular Esquerda/etiologia , Animais , Estudos de Casos e Controles , Células Cultivadas , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Humanos , Hipertensão/genética , Hipertensão/metabolismo , Lipase/genética , Lipase/metabolismo , Masculino , Metaboloma/genética , Camundongos , Camundongos Knockout , Miócitos Cardíacos/metabolismo , Disfunção Ventricular Esquerda/genética , Disfunção Ventricular Esquerda/metabolismo , Remodelação Ventricular
12.
World J Diabetes ; 8(9): 422-428, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28989568

RESUMO

AIM: To investigate matrix metalloproteinase-11 (MMP-11) expression in adipose tissue dysfunction, using in vitro and in vivo models of insulin resistance. METHODS: Culture of mouse 3T3-L1 preadipocytes were induced to differentiation into mature 3T3-L1 adipocytes. Cellular insulin resistance was induced by treating differentiated cultured adipocytes with hypoxia and/or tumor necrosis factor (TNF)-α, and transcriptional changes were analyzed in each condition thereafter. For the in vivo studies, MMP-11 expression levels were measured in white adipose tissue (WAT) from C57BL/6J mice that underwent low fat diet or high-fat feeding in order to induce obesity and obesity-related insulin resistance. Statistical analysis was carried out with GraphPad Prism Software. RESULTS: MMP-11 mRNA expression levels were significantly higher in insulin resistant 3T3-L1 adipocytes compared to control cells (1.46 ± 0.49 vs 0.83 ± 0.21, respectively; P < 0.00036). The increase in MMP-11 expression was observed even in the presence of TNF-α alone (3.79 ± 1.11 vs 1 ± 0.17, P < 0.01) or hypoxia alone (1.79 ± 0.7 vs 0.88 ± 0.1, P < 0.00023). The results obtained in in vitro experiments were confirmed in the in vivo model of insulin resistance. In particular, MMP-11 mRNA was upregulated in WAT from obese mice compared to lean mice (5.5 ± 2.8 vs 1.1 ± 0.7, respectively; P < 3.72E-08). The increase in MMP-11 levels in obese mice was accompanied by the increase in typical markers of fibrosis, such as collagen type VI alpha 3 (Col6α3), and fibroblast-specific protein 1. CONCLUSION: Our results indicate that dysregulation of MMP-11 expression is an early process in the adipose tissue dysfunction, which leads to obesity and obesity-related insulin resistance.

13.
J Am Soc Echocardiogr ; 30(12): 1239-1250.e2, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29066223

RESUMO

BACKGROUND: The subendocardium is highly vulnerable to damage and is thus affected even in subclinical disease stages. Therefore, methods reflecting subendocardial status are of great clinical relevance for the early detection of cardiac damage and the prevention of functional impairment. The aim of this study was to investigate the potential ability of myocardial strain parameters to evaluate changes within the subendocardium. METHODS: Male 129/Sv mice were injected with isoproterenol (ISO; n = 32) to induce isolated subendocardial fibrotic lesions or saline as appropriate control (n = 15). Transthoracic echocardiography was performed using a 30-MHz linear-frequency transducer coupled to a high-resolution imaging system, and acquired images were analyzed for conventional and strain parameters. The degree of collagen content within the different cardiac layers was quantified by histologic analysis and serum levels of tissue inhibitor of metalloproteinase-1, a biomarker for fibrosis, were assessed. RESULTS: ISO treatment induced a marked increase in subendocardial collagen content in response to cell loss (control vs ISO, 0.6 ± 0.3% vs 5.8 ± 0.9%; P < .001) and resulted in a moderate increase in left ventricular wall thickness with preserved systolic function. Global longitudinal peak strain (LS) and longitudinal strain rate were significantly decreased in ISO-treated animals (LS, -15.49% vs -11.49% [P = .001]; longitudinal strain rate, -4.81 vs -3.88 sec-1 [P < .05]), whereas radial and circumferential strain values remained unchanged. Global LS was associated with subendocardial collagen content (r = 0.46, P = .01) and tissue inhibitor of metalloproteinase-1 serum level (r = 0.52, P < .05). Further statistical analyses identified global LS as a superior predictor for the presence of subendocardial fibrosis (sensitivity, 84%; specificity, 80%; cutoff value, -14.4%). CONCLUSION: Assessment of LS may provide a noninvasive method for the detection of subendocardial damage and may consequently improve early diagnosis of cardiac diseases.


Assuntos
Ecocardiografia/métodos , Endocárdio/diagnóstico por imagem , Ventrículos do Coração/diagnóstico por imagem , Disfunção Ventricular Esquerda/diagnóstico , Animais , Modelos Animais de Doenças , Masculino , Camundongos , Reprodutibilidade dos Testes
14.
BMC Med Imaging ; 17(1): 51, 2017 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-28835220

RESUMO

BACKGROUND: Cardiovascular magnetic resonance feature tracking (CMR-FT) is a novel tissue tracking technique developed for noninvasive assessment of myocardial motion and deformation. This preliminary study aimed to evaluate the observer's reproducibility of CMR-FT in a small animal (mouse) model and define sample size calculation for future trials. METHODS: Six C57BL/6 J mice were selected from the ongoing experimental mouse model onsite and underwent CMR with a 3 Tesla small animal MRI scanner. Myocardial deformation was analyzed using dedicated software (TomTec, Germany) by two observers. Left ventricular (LV) longitudinal, circumferential and radial strain (EllLAX, EccSAX and ErrSAX) were calculated. To assess intra-observer agreement data analysis was repeated after 4 weeks. The sample size required to detect a relative change in strain was calculated. RESULTS: In general, EccSAX and EllLAX demonstrated highest inter-observer reproducibility (ICC 0.79 (0.46-0.91) and 0.73 (0.56-0.83) EccSAX and EllLAX respectively). In contrast, at the intra-observer level EllLAX was more reproducible than EccSAX (ICC 0.83 (0.73-0.90) and 0.74 (0.49-0.87) EllLAX and EccSAX respectively). The reproducibility of ErrSAX was weak at both observer levels. Preliminary sample size calculation showed that a small study sample (e.g. ten animals to detect a relative 10% change in EccSAX) could be sufficient to detect changes if parameter variability is low. CONCLUSIONS: This pilot study demonstrates good to excellent inter- and intra-observer reproducibility of CMR-FT technique in small animal model. The most reproducible measures are global circumferential and global longitudinal strain, whereas reproducibility of radial strain is weak. Furthermore, sample size calculation demonstrates that a small number of animals could be sufficient for future trials.


Assuntos
Ventrículos do Coração/diagnóstico por imagem , Imagem Cinética por Ressonância Magnética/métodos , Animais , Tamanho Corporal , Camundongos , Camundongos Endogâmicos C57BL , Variações Dependentes do Observador , Projetos Piloto , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Tamanho da Amostra , Software
15.
Clin Sci (Lond) ; 131(15): 1989-2005, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28646121

RESUMO

The renin-angiotensin system (RAS) and obesity have been implicated in vascular outward remodeling, including aneurysms, but the precise mechanisms are not yet understood. We investigated the effect of the angiotensin receptor type 1 (AT1-receptor) antagonist telmisartan on aortic outward remodeling in a diet-induced obesity model in mice. C57/Black6J mice were fed either a low-fat diet (LFD) or a high-fat diet (HFD) for 14 weeks. One group of HFD mice was additionally exposed to telmisartan (3 mg/kg per day) for the last 4 weeks. HFD led to aortic outward remodeling, characterized by increased proteolysis, along with structural changes, such as fragmentation of elastic fibers and decreased elastin content. Vascular damage was associated with up-regulation of matrix metalloproteinase (MMP)-2 (MMP-2), MMP-3, MMP-12, cathepsin D, and cathepsin B. HFD aortae exhibited an enhanced inflammatory status, characterized by tumor necrosis factor α (TNF-α) and interleukin-1ß (IL-1ß) colocalized with adipocytes in the adventitia. HFD resulted in a significant increase in aortic dimensions, evident by ultrasound measurements. Telmisartan abolished aortic dilatation and preserved elastin content. HFD induced enhanced expression of aortic MMP-2, MMP-9, and TNF-α was abrogated by telmisartan. Adventitial proteolytic and inflammatory factors were also examined in samples from human abdominal aneurysms. The expression of TNF-α, IL-1ß, and MMP-9 was higher in the adventitial fat of diseased vessels compared with healthy tissues. Finally, adipocytes treated with TNF-α showed enhanced MMP-2, MMP-3, and cathepsin D, which was prevented by telmisartan. Taken together, HFD in mice induced aortic dilatation with up-regulation of matrix degrading and inflammatory pathways similar to those seen in human aortic aneurysmatic tissue. The HFD-induced vascular pathology was reduced by AT1-receptor antagonist telmisartan.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/administração & dosagem , Aorta/metabolismo , Obesidade/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Doenças Vasculares/fisiopatologia , Animais , Aorta/efeitos dos fármacos , Dieta Hiperlipídica/efeitos adversos , Humanos , Metaloproteinase 12 da Matriz/genética , Metaloproteinase 12 da Matriz/metabolismo , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 3 da Matriz/genética , Metaloproteinase 3 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/complicações , Obesidade/etiologia , Obesidade/genética , Receptor Tipo 1 de Angiotensina/genética , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Doenças Vasculares/tratamento farmacológico , Doenças Vasculares/etiologia , Remodelação Vascular
16.
Biochem Biophys Res Commun ; 485(2): 312-318, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28232185

RESUMO

Monocyte migration is a key element in atherosclerosis. LDL-C facilitates monocyte migration via induction of CCR2. PCSK9 regulates cell surface expression of the LDL-R and is expressed in vascular smooth muscle cells (VSMCs). The present study was done to investigate the regulation of PCSK9 in VSMCs and its impact on monocyte function. METHODS AND RESULTS: PCSK9 mRNA and protein levels were upregulated in VSMCs by the TLR-4 ligand LPS, whereas TGF-ß or angiotensin II had no effect. Induction of PCSK9 was selectively inhibited by TLR-4 blockade and further downstream by the SAPK/JNK-inhibitor SP600125, whereas inhibitors of ERK1/2, p38 or PI3-kinase pathways had no effect. Incubation of monocytes in conditioned media from LPS-stimulated VSMCs resulted in a significant reduction of LDL-R levels on monocytes, comparable to the effects of recombinant PCSK9. LDL-C increased monocyte CCR2 expression, which augmented monocyte migration towards MCP-1. This LDL-C dependent monocyte chemotaxis was inhibited by supernatants from LPS-stimulated VSMCs, similar to recombinant PCSK9 and a specific LDL-R blocking antibody. CONCLUSION: PCSK9 is regulated in VSMCs by TLR-4 - SAPK/JNK signaling, a pathway important in inflammation and metabolism. VSMC-derived PCSK9 reduces monocyte LDL-R expression, affecting LDL-C/LDL-R-mediated CCR2-expression on monocytes, which is crucial to cell motility and atherogenesis.


Assuntos
Monócitos/imunologia , Pró-Proteína Convertase 9/imunologia , Receptores CCR2/imunologia , Animais , Aterosclerose/imunologia , Linhagem Celular , Células Cultivadas , Quimiotaxia de Leucócito , Humanos , Inflamação/imunologia , Lipopolissacarídeos/imunologia , Masculino , Monócitos/citologia , Músculo Liso Vascular/citologia , Músculo Liso Vascular/imunologia , Ratos Sprague-Dawley , Receptores CCR2/análise , Receptor 4 Toll-Like/imunologia
17.
Sci Rep ; 7: 43269, 2017 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-28233809

RESUMO

Estrogen receptor alpha (ERα) is a major regulator of metabolic processes in obesity. In this study we aimed to define the relevance of adipose tissue ERα during high-fat diet (HFD)-induced obesity using female aP2-Cre-/+/ERαfl/fl mice (atERαKO). HFD did not affect body weight or glucose metabolism in atERαKO- compared to control mice. Surprisingly, HFD feeding markedly increased mortality in atERαKO mice associated with a destructive bacterial infection of the uterus driven by commensal microbes, an alteration likely explaining the absence of a metabolic phenotype in HFD-fed atERαKO mice. In order to identify a mechanism of the exaggerated uterine infection in HFD-fed atERαKO mice, a marked reduction of uterine M2-macrophages was detected, a cell type relevant for anti-microbial defence. In parallel, atERαKO mice exhibited elevated circulating estradiol (E2) acting on E2-responsive tissue/cells such as macrophages. Accompanying cell culture experiments showed that despite E2 co-administration stearic acid (C18:0), a fatty acid elevated in plasma from HFD-fed atERαKO mice, blocks M2-polarization, a process known to be enhanced by E2. In this study we demonstrate an unexpected phenotype in HFD-fed atERαKO involving severe uterine bacterial infections likely resulting from a previously unknown negative interference between dietary FAs and ERα-signaling during anti-microbial defence.


Assuntos
Tecido Adiposo/metabolismo , Infecções Bacterianas/etiologia , Dieta Hiperlipídica , Receptor alfa de Estrogênio/metabolismo , Cervicite Uterina/microbiologia , Animais , Células Cultivadas , Receptor alfa de Estrogênio/genética , Feminino , Macrófagos/metabolismo , Camundongos , Camundongos Knockout , Fagocitose , Transdução de Sinais , Cervicite Uterina/metabolismo
18.
Eur J Med Chem ; 126: 590-603, 2017 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-27918994

RESUMO

In this structure-activity relationship study, the influence of aryl substituents at position 5 or 6 on the pharmacological profile of the partial PPARγ agonist 4'-((2-propyl-1H-benzo[d]imidazol-1-yl)methyl)-[1,1'-biphenyl]-2-carboxylic acid was investigated. This lead was previously identified as the essential part of telmisartan to induce PPARγ activation. Para-OCH3-phenyl substitution strongly increased potency and efficacy independent of the position. Both compounds represent full agonists because of strong hydrophobic contacts with the amino acid Phe363 in the ligand binding domain. Partial agonists with higher potency than telmisartan or the lead were obtained with OH or Cl substituents at the phenyl ring. Molecular modeling suggested additional hydrogen or halogen bonds with Phe360 located at helix 7. It is assumed that these interactions fix helix 7, thereby promoting a partial agonist conformation of the receptor. The theoretical considerations correlate very well with the results from the luciferase transactivation assay using hPPARγ-LBD as well as those from a time-resolved fluorescent resonance energy transfer (TR-FRET) assay in which the coactivator (TRAP220, PGC-1α) recruitment and corepressor (NCoR1) release pattern was investigated.


Assuntos
Benzimidazóis/farmacologia , Benzoatos/farmacologia , PPAR gama/agonistas , Benzimidazóis/química , Humanos , Modelos Moleculares , Correpressor 1 de Receptor Nuclear/efeitos dos fármacos , Correpressor 1 de Receptor Nuclear/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Ligação Proteica , Relação Estrutura-Atividade , Telmisartan
19.
Eur J Med Chem ; 124: 138-152, 2016 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-27569195

RESUMO

In previous studies, the 4'-((2-propyl-1H-benzo[d]imidazol-1-yl)methyl)-[1,1'-biphenyl]-2-carboxylic acid was identified as pharmacophoric core for PPARγ activation. In this structure-activity relationship study the C2-alkyl chain was elongated and the 2-COOH group was changed to a carbamide/carbonitrile or shifted to the 3- or 4-position. Furthermore, the benzo[d]imidazole was exchanged by 2,3-dihydrobenzo[d]thiazole or 1H-indole. C2-propyl derivatives showed the profile of partial agonists, while elongation of the C2-chain to that of an n-heptyl group or a 4-COOH shift changed the pharmacological profile to that of a potent full agonist. This finding can be explained by binding to the LBD in different ligand conformations. Two anchoring points (Tyr473 and Arg288) exist in the LBD, which have to be contacted to achieve receptor activation. In a crystal violet chemosensitivity assay using COS-7 cells and LNCaP cells expressing PPARγ only the carbamide derivatives influenced the cell growth, independently on the presence of the PPARγ. Therefore, receptor mediated cytotoxicity can be excluded.


Assuntos
Benzimidazóis/química , Benzimidazóis/farmacologia , Benzoatos/química , Benzoatos/farmacologia , PPAR gama/agonistas , PPAR gama/metabolismo , Células 3T3-L1 , Animais , Benzimidazóis/metabolismo , Benzoatos/metabolismo , Células COS , Diferenciação Celular/efeitos dos fármacos , Cercopithecus aethiops , Desenho de Drogas , Camundongos , Simulação de Acoplamento Molecular , PPAR gama/química , PPAR gama/genética , Ligação Proteica , Conformação Proteica , Relação Estrutura-Atividade , Telmisartan , Ativação Transcricional/efeitos dos fármacos
20.
Metabolism ; 65(6): 935-43, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27173472

RESUMO

INTRODUCTION: In weight loss trials, a considerable inter-individual variability in reduction of fat mass and changes of insulin resistance is observed, even under standardized study conditions. The underlying mechanisms are not well understood. Given the metabolic properties of the atrial natriuretic peptide (ANP) system, we hypothesized that ANP signaling might be involved in this phenomenon by changes of ANP secretion or receptor balance. Therefore, we investigated the impact of systemic, adipose and myocellular ANP system on metabolic and anthropometric improvements during weight loss. METHODS: We comprehensively investigated 143 subjects (31 male, 112 female) before and after a 3 month-standardized weight loss program. The time course of BMI, fat mass, insulin sensitivity, circulating mid-regional proANP (MR-proANP) levels as well as adipose and myocellular natriuretic receptor A (NPR-A) and C (NPR-C) mRNA expression were investigated. RESULTS: BMI decreased by -12.6±3.7%. This was accompanied by a remarkable decrease of adipose NPR-C expression (1005.0±488.4 vs. 556.7±465.6; p<0.001) as well as a tendency towards increased adipose NPR-A expression (4644.7±946.8 vs. 4877.6±869.8; p=0.051). Weight loss induced changes in NPR-C (ΔNPR-C) was linked to relative reduction of total fat mass (ΔFM) (r=0.281; p<0.05), reduction of BMI (r=0.277; p<0.01), and increase of free fatty acids (ΔFFA) (r=-0.258; p<0.05). Basal NPR-C expression and weight loss induced ΔNPR-C independently explained 22.7% of ΔFM. In addition, ΔMR-proANP was independently associated with improvement of insulin sensitivity (standardized ß=0.246, p<0.01). DISCUSSION: ANP receptor expression predicted the degree of weight loss induced fat mass reduction. Our comprehensive human data support that peripheral ANP signalling is involved in control of adipose tissue plasticity and function during weight loss. (Funded by the Deutsche Forschungsgemeinschaft (KFO281/2), the Berlin Institute of Health (BIH) and the German Centre for Cardiovascular Research (DZHK/BMBF); ClinicalTrials.gov number: NCT00850629).


Assuntos
Tecido Adiposo/fisiologia , Adiposidade/fisiologia , Fator Natriurético Atrial/metabolismo , Resistência à Insulina/fisiologia , Sobrepeso/terapia , Receptores do Fator Natriurético Atrial/metabolismo , Perda de Peso/fisiologia , Adulto , Glicemia , Índice de Massa Corporal , Restrição Calórica , Aconselhamento , Terapia por Exercício , Feminino , Humanos , Insulina/sangue , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Obesidade/dietoterapia , Obesidade/metabolismo , Obesidade/terapia , Sobrepeso/dietoterapia , Sobrepeso/metabolismo , Programas de Redução de Peso
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