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1.
Ultraschall Med ; 42(2): 178-186, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32663881

RESUMO

BACKGROUND: This prospective multicenter study funded by the DEGUM assesses the diagnostic accuracy of standardized contrast-enhanced ultrasound (CEUS) for the noninvasive diagnosis of hepatocellular carcinoma (HCC) in high-risk patients. METHODS: Patients at high risk for HCC with a histologically proven focal liver lesion on B-mode ultrasound were recruited prospectively in a multicenter approach. Clinical and imaging data were entered via online entry forms. The diagnostic accuracies for the noninvasive diagnosis of HCC were compared for the conventional interpretation of standardized CEUS at the time of the examination (= CEUS on-site) and the two CEUS algorithms ESCULAP (Erlanger Synopsis for Contrast-enhanced Ultrasound for Liver lesion Assessment in Patients at risk) and CEUS LI-RADS (Contrast-Enhanced UltraSound Liver Imaging Reporting and Data System). RESULTS: 321 patients were recruited in 43 centers; 299 (93.1 %) had liver cirrhosis. The diagnosis according to histology was HCC in 256 cases, and intrahepatic cholangiocarcinoma (iCCA) in 23 cases. In the subgroup of cirrhotic patients (n = 299), the highest sensitivity for the diagnosis of HCC was achieved with the CEUS algorithm ESCULAP (94.2 %) and CEUS on-site (90.9 %). The lowest sensitivity was reached with the CEUS LI-RADS algorithm (64 %; p < 0.001). However, the specificity of CEUS LI-RADS (78.9 %) was superior to that of ESCULAP (50.9 %) and CEUS on-site (64.9 %; p < 0.001). At the same time, the negative predictive value (NPV) of CEUS LI-RADS was significantly inferior to that of ESCULAP (34.1 % vs. 67.4 %; p < 0.001) and CEUS on-site (62.7 %; p < 0.001). The positive predictive values of all modalities were high (around 90 %), with the best results seen for CEUS LI-RADS and CEUS on-site. CONCLUSION: This is the first multicenter, prospective comparison of standardized CEUS and the recently developed CEUS-based algorithms in histologically proven liver lesions in cirrhotic patients. Our results reaffirm the excellent diagnostic accuracy of CEUS for the noninvasive diagnosis of HCC in high-risk patients. However, on-site diagnosis by an experienced examiner achieves an almost equal diagnostic accuracy compared to CEUS-based diagnostic algorithms.


Assuntos
Neoplasias dos Ductos Biliares , Carcinoma Hepatocelular , Neoplasias Hepáticas , Algoritmos , Carcinoma Hepatocelular/diagnóstico por imagem , Meios de Contraste , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Imageamento por Ressonância Magnética , Estudos Prospectivos , Ultrassonografia
3.
Liver Int ; 35(12): 2556-63, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26010514

RESUMO

BACKGROUND & AIMS: Vascular hyporeactivity to vasoconstrictors contributes to splanchnic arterial vasodilatation and hemodynamic dysregulation in portal hypertension. Neuropeptide Y (NPY), a sympathetic cotransmitter, has been shown to improve adrenergic vascular contractility in portal hypertensive rats and markedly attenuate hyperdynamic circulation. To further characterize the NPY-effects in portal hypertension, we investigated its role for non-receptor-mediated vasoconstriction in the superior mesenteric artery (SMA) of portal vein ligated (PVL) and sham-operated rats. METHODS: Ex vivo SMA perfusion of PVL and sham rats was used to analyse the effects of NPY on pressure response to non-receptor-mediated vasoconstriction. Dose-response curves to KCl (30-300 mM) were used to bypass G protein-coupled receptor mechanisms. Potential involvement of the cyclooxygenase-pathway was tested by non-selective cyclooxygenase-inhibition using indomethacin. RESULTS: KCl-induced vascular contractility but not vascular sensitivity was significantly attenuated in PVL rats as compared with sham rats. Administration of NPY resulted in an augmentation of KCl-evoked vascular sensitivity being not different between study groups. However, KCl-induced vascular contractility was markedly more enhanced in PVL rats, thus, vascular response was no more significantly different between PVL and sham rats after addition of NPY. Administration of indomethacin abolished the NPY-induced enhancement of vasoconstriction. CONCLUSIONS: Receptor-independent vascular contractility is impaired in mesenteric arteries in portal hypertension. NPY improves non-receptor mediated mesenteric vasoconstriction more effective in portal hypertension than in healthy conditions correcting splanchnic vascular hyporesponsiveness. This beneficial vasoactive action of NPY adds to its well known more pronounced effects on adrenergic vasoconstriction in portal hypertension making it a promising therapeutic agent in portal hypertension.


Assuntos
Hipertensão Portal , Artéria Mesentérica Superior , Neuropeptídeo Y/metabolismo , Vasoconstrição/efeitos dos fármacos , Animais , Inibidores de Ciclo-Oxigenase/farmacologia , Hemodinâmica/efeitos dos fármacos , Hipertensão Portal/metabolismo , Hipertensão Portal/fisiopatologia , Indometacina/farmacologia , Masculino , Artéria Mesentérica Superior/efeitos dos fármacos , Artéria Mesentérica Superior/metabolismo , Artéria Mesentérica Superior/fisiopatologia , Cloreto de Potássio/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores de Neuropeptídeo Y/metabolismo , Circulação Esplâncnica/efeitos dos fármacos , Vasoconstritores/metabolismo , Vasoconstritores/farmacologia
4.
Gut ; 60(8): 1122-32, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21317421

RESUMO

BACKGROUND: Splanchnic vasodilation triggers the development of the hyperdynamic circulatory syndrome in portal hypertension. Neuropeptide Y (NPY), a sympathetic co-transmitter of norepinephrine, improves contractility in mesenteric arteries of pre-hepatic portal hypertensive rats. Therefore, we investigated the effect of NPY on mesenteric arterial contractility in vitro and in vivo in cirrhotic ascitic rats, as well as the vasoactive pathways involved. METHODS: All experiments were performed in CCl4-induced cirrhotic rats with ascites and compared to controls. In vivo haemodynamic characterisation was assessed before and after cumulative application of NPY i.v. using the microspheres technique. In vitro mesenteric arterial perfusion was used to analyse the effect of NPY on the response to α1-adrenergic, as well as nitrergic stimulation. The NPY effects on vasoactive pathways (RhoA/Rho-kinase and NOS/NO) were analysed by western blot in mesenteric arteries. RESULTS: NPY decreased portal-venous blood flow and reduced portal pressure in cirrhotic rats, without changes in mean arterial pressure. This was accompanied by decreased cardiac output and normalised systemic vascular resistance in cirrhotic rats. By contrast, no significant splanchnic or systemic haemodynamic effect of NPY was seen in controls. NPY enhanced arterial contractility in cirrhotic but not in control rats. Furthermore, NO-mediated vasodilation was reduced to a greater extent than in controls. These findings were paralleled by an increased expression and activity of the constrictive Rho-kinase pathway and decreased activation of vasodilating NOS/NO signalling after NPY administration in mesenteric arteries. CONCLUSIONS: NPY exerts marked portal hypotensive effects and ameliorates the hyperdynamic circulation in cirrhotic ascitic rats. This is mediated mainly by a pronounced splanchnic vasoconstriction and reduction in splanchnic blood flow due to enhanced Rho-kinase expression and activity, as well as reduced NOS activation and NO effect.


Assuntos
Hipertensão Portal/tratamento farmacológico , Cirrose Hepática Experimental/complicações , Neuropeptídeo Y/uso terapêutico , Pressão na Veia Porta/efeitos dos fármacos , Circulação Esplâncnica/fisiologia , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Animais , Western Blotting , Hipertensão Portal/etiologia , Hipertensão Portal/fisiopatologia , Infusões Intravenosas , Cirrose Hepática Experimental/enzimologia , Cirrose Hepática Experimental/fisiopatologia , Masculino , Neuropeptídeo Y/administração & dosagem , Óxido Nítrico Sintase/metabolismo , Perfusão/métodos , Pressão na Veia Porta/fisiologia , Ratos , Ratos Sprague-Dawley , Circulação Esplâncnica/efeitos dos fármacos , Síndrome , Resultado do Tratamento , Proteína rhoA de Ligação ao GTP/metabolismo
5.
Exp Mol Pathol ; 91(3): 780-3, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21855538

RESUMO

Non-alcoholic fatty liver disease (NAFLD) is strongly associated with obesity and the metabolic syndrome. It encompasses a clinico-pathologic spectrum of conditions ranging from simple steatosis to nonalcoholic steatohepatitis (NASH). The latter develops upon pro-inflammatory cell infiltration and is widely considered as the first relevant pathophysiological step in NAFLD-progression. The chemokine monocyte chemoattractant protein 1 (MCP-1) plays an important role in the progression of hepatic inflammation and fibrosis, and both increased hepatic expression and circulating serum levels have been described in NASH. Here, we aimed to investigate MCP-1 expression in simple hepatic steatosis. Upon feeding a high-fat diet mice developed hepatic steatosis in the absence of significant hepatic inflammation, but elevated hepatic MCP-1 expression compared to control mice fed a standard chow. Interestingly, high-fat diet fed mice had significantly higher MCP-1 serum levels, and MCP-1 mRNA expression was significantly increased in visceral adipose tissue. Furthermore, MCP-1 serum levels were also elevated in patients with ultrasound-diagnosed NAFLD and correlated with the body-mass index and fasting glucose. In conclusion, our data indicate both the liver and adipose tissue as cellular sources of elevated circulating MCP-1 levels already in the early phase of hepatic steatosis. Since MCP-1 derived from visceral adipose tissue reaches the liver via portal circulation at high concentrations it may significantly contribute to the progression of simple steatosis to NASH.


Assuntos
Quimiocina CCL2/biossíntese , Fígado Gorduroso/metabolismo , Tecido Adiposo/metabolismo , Tecido Adiposo/patologia , Animais , Índice de Massa Corporal , Quimiocina CCL2/sangue , Dieta Hiperlipídica , Fígado Gorduroso/complicações , Fígado Gorduroso/patologia , Fígado Gorduroso/fisiopatologia , Inflamação , Fígado/metabolismo , Fígado/patologia , Camundongos , Hepatopatia Gordurosa não Alcoólica , Obesidade/complicações , Obesidade/fisiopatologia
6.
Am J Physiol Gastrointest Liver Physiol ; 297(4): G849-57, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19696142

RESUMO

Splanchnic vasodilation is the pathophysiological hallmark in the development of the hyperdynamic circulatory syndrome in liver cirrhosis and portal hypertension. This has been attributed so far mainly to a marked vascular hyporeactivity to endogenous vasoconstrictors. However, myogenic tone and vessel stiffness have not been addressed in mesenteric arteries in liver cirrhosis. CCl(4)(-)-induced ascitic cirrhotic (LC) and age-matched control rats, portal vein-ligated (PVL) rats, and sham-operated rats were investigated. Third-order mesenteric resistance arteries were studied under no-flow conditions using a pressure myograph measuring media thickness and lumen diameter in response to incremental increases in intramural pressure, from which wall mechanics were calculated. Electron microscopy was used for investigation of wall ultrastructure, especially the fenestrae in internal elastic lamina (IEL). In PVL animals, no significant change in passive vessel strain, stress, media-to-lumen ratio, or cross-sectional area was noted. In contrast, in LC rats, vessel strain was markedly elevated compared with healthy control rats, indicating a marked reduction in vessel stiffness. In addition, the strain-stress curve was shifted to the right, and the elastic modulus in dependency on vessel stress decreased, demonstrating predominantly structure-dependent factors to be involved. The media-to-lumen quotient was not significantly altered, but cross-sectional area was highly increased in LC rats, indicating hypertrophic outward remodeling. These findings were paralleled by enlarged fenestrae in the IEL but no change in thickness of IEL or proportion of extracellular matrix or vascular smooth muscle in LC rats. We concluded that, in long-standing severe portal hypertension such as ascitic LC but not in short-term conditions such as PVL, mesenteric resistance arteries exhibit vascular remodeling and markedly less resistant mechanical properties, leading to decreased vessel stiffness accompanied by structural changes in the IEL. This may well contribute to the maintenance and severity of splanchnic arterial vasodilation in LC.


Assuntos
Hipertensão Portal/fisiopatologia , Cirrose Hepática Experimental/fisiopatologia , Artérias Mesentéricas/fisiopatologia , Veia Porta/fisiopatologia , Circulação Esplâncnica , Resistência Vascular , Animais , Fenômenos Biomecânicos , Pressão Sanguínea , Tetracloreto de Carbono , Elasticidade , Hipertensão Portal/etiologia , Hipertensão Portal/patologia , Hipertrofia , Ligadura , Cirrose Hepática Experimental/induzido quimicamente , Cirrose Hepática Experimental/patologia , Masculino , Artérias Mesentéricas/ultraestrutura , Microscopia Eletrônica , Miografia , Veia Porta/cirurgia , Ratos , Ratos Sprague-Dawley , Estresse Mecânico , Vasodilatação
7.
J Gastroenterol Hepatol ; 23(12): 1901-8, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18554237

RESUMO

BACKGROUND AND AIM: The hypothalamic-autonomic nervous system (HANS) axis and the hypothalamic-pituitary-adrenal (HPA) axis are stimulated in parallel in response to stress factors under healthy conditions. This physiological synergism of the axes aims at optimizing anti-inflammatory actions. Therefore, we investigated whether this synergism is altered in patients with liver cirrhosis. METHODS: As a typical marker of the HANS axis neuropeptide Y (NPY is a neurotransmitter of the sympathetic nerve terminal) and of the HPA axis, cortisol together with adrenocorticotropic hormone (ACTH) and cortisol-binding globulin (CBG), were measured in samples from control subjects and patients with liver cirrhosis. RESULTS: Plasma NPY was found to be increased in cirrhotic patients compared to control subjects (P < 0.01). This increase was observed to be independent of the severity of liver disease (Child class). Serum cortisol was decreased in cirrhotics, particularly in patients with Child A cirrhosis. Plasma NPY was positively correlated with serum cortisol in control subjects (r = 0.32, P < 0.05) reflecting the parallel activation of both axes under the normal condition. However, serum cortisol was not correlated with plasma NPY in cirrhotic patients. For the subgroup of Child A patients, even a negative correlation between NPY and cortisol was observed (r = -0.43, P < 0.05). No significant change in serum levels of ACTH and its positive correlation with serum cortisol was observed in cirrhotic patients. CONCLUSIONS: The present study demonstrates that the two stress axes seem to act in parallel fashion in control subjects but are uncoupled in liver cirrhosis. We discuss how uncoupling of the two anti-inflammatory axes can occur and may contribute to the increased susceptibility for infections and lethal complications in cirrhotic patients.


Assuntos
Sistema Hipotálamo-Hipofisário/fisiopatologia , Cirrose Hepática/fisiopatologia , Sistema Hipófise-Suprarrenal/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Hormônio Adrenocorticotrópico/sangue , Adulto , Idoso , Biomarcadores/sangue , Proteínas de Transporte/sangue , Estudos de Casos e Controles , Feminino , Humanos , Hidrocortisona/sangue , Sistema Hipotálamo-Hipofisário/metabolismo , Cirrose Hepática/sangue , Masculino , Pessoa de Meia-Idade , Neuropeptídeo Y/sangue , Sistema Hipófise-Suprarrenal/metabolismo , Índice de Gravidade de Doença , Sistema Nervoso Simpático/metabolismo
8.
Visc Med ; 34(2): 97-100, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29888237

RESUMO

BACKGROUND: Due to the high prevalence and incidence of patients with gastroesophageal reflux disease (GERD), the diagnostic workup of patients with symptoms of GERD needs to be balanced between empiric antisecretory therapy and further functional assessment including endoscopy and reflux monitoring. METHODS: This article is based on a literature review (PubMed, Medline) using the terms 'gastroesophageal reflux disease' or 'GERD' and 'diagnosis', 'therapy', or 'PPI' with special and critical analysis of the current 'Porto' consensus report. RESULTS AND CONCLUSIONS: Further diagnostics are mandatory in case of alarm symptoms as well as atypical or persistent symptoms under adequate therapy with proton pump inhibitors (PPI). In general, the clinical situation needs to be clarified before sending the patients for reflux monitoring. The question is not only when and whom to test but also how to test: on or off PPI therapy, pH-metry, or combined pH-impedance analysis. These questions have been defined in a recent consensus report of an international panel of experts and are further discussed in this article.

9.
Metabolism ; 59(5): 664-70, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-19913846

RESUMO

No detailed data are available on hepatic clearance, postprandial release, and distribution profile of metabolically active adipokines in splanchnic blood compartments such as portal and hepatic veins. This would be a prerequisite for understanding the role of visceral adipose tissue-derived adipokines in metabolism. Adiponectin, resistin, leptin, and visfatin concentrations were measured by enzyme-linked immunosorbent assay in peripheral veins, arterial blood, hepatic veins, and portal veins in 50 patients with liver cirrhosis undergoing transjugular intrahepatic portosystemic shunt implantation, in 6 patients with normal liver function, and in fasted and fed rats. Adiponectin, leptin, resistin, and visfatin did not differ among blood compartments in normal-weight probands in the fasted state. Adiponectin and leptin levels were similar in patients with and without liver cirrhosis. Systemic visfatin levels were decreased and resistin levels were increased in liver cirrhosis. Visfatin secretion was higher from visceral than from peripheral subcutaneous adipose tissue in liver cirrhosis. There was no hepatic clearance of visfatin. Leptin secretion was higher from peripheral than from visceral adipose tissue. Leptin did not undergo hepatic clearance. Resistin and adiponectin did not differ between blood compartments in liver cirrhosis. Resistin concentrations increased upon feeding in rats, and there was an increase in the postprandial clearance of adiponectin by the liver. A postprandial increase of leptin concentrations was restricted to peripheral adipose tissue in rats. The results give insight into the dynamics of splanchnic adipokine concentrations and help critically interpret data derived from messenger RNA expression studies.


Assuntos
Adipocinas/sangue , Gordura Intra-Abdominal/metabolismo , Fígado/irrigação sanguínea , Fígado/metabolismo , Adiponectina/sangue , Animais , Estudos de Coortes , Ensaio de Imunoadsorção Enzimática , Feminino , Veias Hepáticas/metabolismo , Humanos , Leptina/sangue , Cirrose Hepática/metabolismo , Masculino , Pessoa de Meia-Idade , Nicotinamida Fosforribosiltransferase/sangue , Veia Porta/metabolismo , Período Pós-Prandial , Ratos , Ratos Sprague-Dawley , Resistina/sangue , Circulação Esplâncnica , Estatísticas não Paramétricas
10.
World J Gastroenterol ; 16(15): 1837-44, 2010 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-20397260

RESUMO

AIM: To explore the role of heat shock protein-90 (HSP-90) for nitrergic vasorelaxation in the splanchnic circulation in rats with and without portal hypertension. METHODS: Neuronal nitric oxide synthase (nNOS) and HSP-90 were analyzed by immunofluorescence, western blotting and co-immunoprecipitation in the mesenteric vasculature and isolated nerves of portal-vein-ligated (PVL) rats and sham operated rats. In vitro perfused de-endothelialized mesenteric arterial vasculature was preconstricted with norepinephrine (EC(80)) and tested for nNOS-mediated vasorelaxation by periarterial nerve stimulation (PNS, 2-12 Hz, 45V) before and after incubation with geldanamycin (specific inhibitor of HSP-90 signalling, 3 microg/mL) or L-NAME (non-specific NOS-blocker, 10(-4) mol/L). RESULTS: nNOS and HSP-90 expression was significantly increased in mesenteric nerves from PVL as compared to sham rats. Moreover, nNOS and HSP-90 were visualized in mesenteric nerves by immunofluorescence and immunoprecipitation of nNOS co-immunoprecipitated HSP-90 in sham and PVL rats. PNS induced a frequency-dependent vasorelaxation which was more pronounced in PVL as compared to sham rats. L-NAME and geldanamycin markedly reduced nNOS-mediated vasorelaxation abrogating differences between the study groups. The effect of L-NAME and geldanamycin on nNOS-mediated vasorelaxation was significantly greater in PVL than in sham animals. However, no difference in magnitude of effect between L-NAME and geldanamycin was noted. CONCLUSION: HSP-90 acts as a signalling mediator of nNOS-dependent nerve mediated vascular responses in mesenteric arteries, and the increased nitrergic vasorelaxation observed in portal hypertension is mediated largely by HSP-90.


Assuntos
Proteínas de Choque Térmico HSP90/metabolismo , Hipertensão Portal/patologia , Artérias Mesentéricas/patologia , Óxido Nítrico Sintase Tipo I/metabolismo , Vasodilatação , Animais , Benzoquinonas/farmacologia , Western Blotting , Hipertensão Portal/metabolismo , Imunoprecipitação , Lactamas Macrocíclicas/farmacologia , Masculino , Microscopia de Fluorescência/métodos , NG-Nitroarginina Metil Éster/farmacologia , Perfusão , Ratos , Ratos Sprague-Dawley
11.
J Med Case Rep ; 4: 110, 2010 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-20409321

RESUMO

INTRODUCTION: The syndrome of inappropriate antidiuresis is the most common cause of euvolemic hypo-osmolality. This syndrome is associated with a wide variety of diseases. However, its most frequent causes are related to malignancies, especially lung cancer. In this case report, we describe an unknown association of the syndrome of inappropriate antidiuresis with papillary thyroid cancer. CASE PRESENTATION: We present the case of a 71-year-old Caucasian, German woman with marked hyponatremia and neurological symptoms. After a detailed clinical investigation, the common causes of syndrome of inappropriate antidiuresis and other malignancies were ruled out. A thyroid nodule was detected by ultrasound and magnetic resonance imaging. Although fine needle aspiration cytology showed negative results, our patient underwent surgery. Papillary thyroid cancer was later diagnosed. After total thyroidectomy, a complete remission of the clinical symptoms occurred and our patient subsequently had iodine-131 radioactive therapy. Hyponatremia was no longer observed during the follow-up investigations. CONCLUSION: This is the first reported case of paraneoplastic syndrome of inappropriate antidiuresis caused by papillary thyroid carcinoma. Since its symptoms occurred before the development of local symptoms, total thyroidectomy may provide a timely and efficient treatment for the underlying malignancy.

12.
Int J Clin Exp Pathol ; 3(7): 675-80, 2010 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-20830238

RESUMO

Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum ranging from simple steatosis to cirrhosis. Hepatocellular lipid accumulation is a hallmark of both nonalcoholic steatosis and steatohepatitis (NASH). The latter develops upon pro-inflammatory cell infiltration and is widely considered as the first relevant pathophysiological step in NAFLD-progression. The chemokine CCL5/RANTES plays an important role in the progression of hepatic inflammation and fibrosis. We here aimed to investigate its expression in NAFLD. Incubation of primary human hepatocytes with palmitic acid induced a dose-dependent lipid accumulation, and corresponding dose-dependent RANTES induction in vitro. Furthermore, we observed significantly elevated hepatic RANTES expression in a dietary model of NAFLD, in which mice were fed a high-fat diet for 12 weeks. This diet induced significant hepatic steatosis but only minimal inflammation. In contrast to the liver, RANTES expression was not induced in visceral adipose tissue of the group fed with high-fat diet. Finally, RANTES serum levels were elevated in patients with ultrasound-diagnosed NAFLD. In conclusion, our data indicate hepatocytes as cellular source of elevated hepatic as well as circulating RANTES levels in response to hepatic steatosis. Noteworthy, upregulation of RANTES in response to lipid accumulation occurs in the absence of relevant inflammation, which further indicates that hepatic steatosis per se has pathophysiological relevance and should not be considered as benign.


Assuntos
Quimiocina CCL5/biossíntese , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Hepatite/metabolismo , Animais , Linhagem Celular , Hepatite/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C
13.
J Hepatol ; 44(3): 512-9, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16324766

RESUMO

BACKGROUND/AIMS: Vascular hyporeactivity to catecholamines contributes to arterial vasodilation and hemodynamic dysregulation in portal hypertension. Neuropeptide Y (NPY) is a sympathetic neurotransmitter facilitating adrenergic vasoconstriction via Y1-receptors on the vascular smooth muscle. Therefore, we investigated its role for vascular reactivity in the superior mesenteric artery (SMA) of portal vein ligated (PVL) and sham operated rats. METHODS: In vitro perfused SMA vascular beds of rats were tested for the cumulative dose-response to NPY dependent on the presence and level of alpha1-adrenergic vascular tone (methoxamine MT: 0.3-10 microM). Moreover, the effect of NPY (50 nM) on vascular responsiveness to alpha1-adrenergic stimulation (MT: 0.3-300 microM) was evaluated. Y1-receptor function was tested by Y1-selective inhibition using BIBP-3226 (1 microM). RESULTS: NPY dose-dependently and endothelium-independently enhanced MT-pre-constriction in SMA. This potentiation was increasingly effective with increasing adrenergic pre-stimulation and being more pronounced in PVL rats as compared to sham rats at high MT concentrations. NPY enhanced vascular contractility only in PVL rats correcting the adrenergic vascular hyporeactivity. Y1-receptor inhibition completely abolished NPY-evoked vasoconstrictive effects. CONCLUSIONS: NPY endothelium-independently potentiates adrenergic vasoconstriction via Y1-receptors being more pronounced in portal hypertension improving mesenteric vascular contractility and thereby correcting the splanchnic vascular hyporeactivity. This makes NPY a superior vasoconstrictor counterbalancing arterial vasodilation in portal hypertension.


Assuntos
Hipertensão Portal/fisiopatologia , Artéria Mesentérica Superior/fisiopatologia , Neuropeptídeo Y/administração & dosagem , Receptores de Neuropeptídeo Y/efeitos dos fármacos , Vasoconstrição/efeitos dos fármacos , Agonistas alfa-Adrenérgicos/farmacologia , Animais , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Hipertensão Portal/metabolismo , Técnicas In Vitro , Masculino , Artéria Mesentérica Superior/efeitos dos fármacos , Artéria Mesentérica Superior/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/fisiopatologia , Norepinefrina/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores de Neuropeptídeo Y/metabolismo
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