RESUMO
Mammalian and reptilian vascular tissues present basal release of 6-nitrodopamine, which is reduced when the tissues are pre-incubated with the NO synthase inhibitor L-NG-Nitro arginine methyl ester (L-NAME), or when the endothelium is mechanically removed. 6-Nitrodopamine induces vasorelaxation in pre-contracted vascular rings by antagonizing the dopaminergic D2-like receptor. Here it was investigated whether male swine vessels (including carotid, left descendent coronary, renal, and femoral arteries) release 6-nitrodopamine, dopamine, noradrenaline, and adrenaline, as measured by liquid chromatography coupled to tandem mass spectrometry. The in vitro vasorelaxant action of 6-nitrodopamine was evaluated in carotid, coronary, renal, and femoral arteries precontracted by U-46619 (3 nM), and compared to that induced by the dopamine D2-receptor antagonist L-741,626. Expression of tyrosine hydroxylase and the neuromaker calretinin was investigated by immunohistochemistry. All vascular tissues presented basal release of endothelium-derived catecholamines. The relaxation induced by 6-nitrodopamine was not affected by preincubation of the tissues with either L-NAME (100 µM, 30-min preincubation) or the heme-site inhibitor of soluble guanylyl cyclase ODQ (100 µM, 30-min preincubation). Electrical field stimulation (EFS)-induced contractions were significantly potentiated by previous incubation with L-NAME, but unaffected by ODQ preincubation. The contractions induced by EFS were reduced by preincubation with either 6-nitrodopamine or L-741,626. Immunohistochemistry in all arteries revealed the presence of tyrosine hydroxylase in the endothelium, whereas immunoreactivity for calretinin was negative. Swine vessels present basal release of endothelium-derived catecholamines and expression of tyrosine hydroxylase in the endothelium. The vasodilation induced by 6-nitrodopamine is due to blockade of dopaminergic D2-like receptors.
Assuntos
Vasodilatação , Animais , Masculino , Vasodilatação/efeitos dos fármacos , Suínos , Artéria Femoral/efeitos dos fármacos , Artéria Femoral/metabolismo , Artéria Femoral/fisiologia , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/fisiologia , Vasos Coronários/metabolismo , Artéria Renal/efeitos dos fármacos , Artéria Renal/metabolismo , Artéria Renal/fisiologia , Dopamina/metabolismo , Artérias Carótidas/efeitos dos fármacos , Artérias Carótidas/metabolismo , Artérias Carótidas/fisiologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Endotélio Vascular/fisiologia , Vasodilatadores/farmacologiaRESUMO
Systemic arterial hypertension is a public health problem associated with an increased risk of cardiovascular disease. Matrix metalloproteinases (MMP) are endopeptidases that participate in hypertension-induced cardiovascular remodeling, which may be activated by oxidative stress. Angiotensin II (Ang II), a potent hypertrophic and vasoconstrictor peptide, increases oxidative stress, MMP-2 activity and tumor necrosis factor (TNF-α) expression. In vitro studies have shown that TNF-α is essential for Ang II-induced MMP-2 expression. Thus, this study evaluated whetherTNF-α inhibition decreases the development of hypertension-induced vascular remodeling via reduction of MMP-2 activity and reactive oxygen species (ROS) formation. Two distinct pharmacological approaches were used in the present study: Pentoxifylline (PTX), a non-selective inhibitor of phosphodiesterases that exerts anti- inflammatory effects via inhibition of TNF-α, and Etanercept (ETN), a selective TNF-α inhibitor. 2-kidney and 1-Clip (2K1C). 2-kidney and 1-Clip (2K1C) and Sham rats were treated with Vehicle, PTX (50 mg/Kg and 100 mg/kg daily) or ETN (0.3 mg/Kg and 1 mg/kg; three times per week). Systolic blood pressure (SBP) was measured weekly by tail cuff plethysmography. Plasma TNF-α and IL-1ß levels were evaluated by enzyme-linked immunosorbent assay (ELISA) technique. The vascular hypertrophy was examined in the aorta sections stained with hematoxylin/eosin. ROS in aortas was evaluated by dihydroethidium and chemiluminescence lucigenin assay. Aortic MMP-2 levels and activity were evaluated by gel zymography and in situ zymography, respectively. The 2K1C animals showed a progressive increase in SBP levels and was accompanied by significant vascular hypertrophy (p < 0.05 vs Sham). Treatment with PTX at higher doses decreased SBP and vascular remodeling in 2K1C animals (p < 0.05 vs 2K1C vehicle). Although the highest dose of ETN treatment did not reduce blood pressure, the vascular hypertrophy was significantly attenuated in 2K1C animals treated with ETN1 (p < 0.05). The increased cytokine levels and ROS formation were reversed by the highest doses of both PTX and ETN. The increase in MMP-2 levels and activity in 2K1C animals were reduced by PTX100 and ETN1 treatments (p < 0.05 vs vehicle 2K1C). Lower doses of PTX and ETN did not affect any of the evaluated parameters in this study, except for a small reduction in TNF-α levels. The findings of the present study suggest that PTX and ETN treatment exerts immunomodulatory effects, blunted excessive ROS formation, and decreased renovascular hypertension-induced MMP-2 up-regulation, leading to improvement ofvascular remodeling typically found in 2K1C hypertension. Therefore, strategies using anti-hypertensive drugs in combination with TNF alpha inhibitors could be an attractive therapeutic approach to tackle hypertension and its associated vascular remodeling.
Assuntos
Anti-Hipertensivos/farmacologia , Etanercepte/farmacologia , Metaloproteinase 2 da Matriz/metabolismo , Pentoxifilina/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Remodelação Vascular/efeitos dos fármacos , Animais , Aorta/efeitos dos fármacos , Aorta/metabolismo , Aorta/patologia , Pressão Sanguínea/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Hipertensão , Hipertrofia , Masculino , Ratos Wistar , Artéria Renal/efeitos dos fármacos , Artéria Renal/metabolismo , Artéria Renal/patologiaRESUMO
Endothelial dysfunction in uremia can result in cell-to-cell junction loss and increased permeability, contributing to cardiovascular diseases (CVD) development. This study evaluated the impact of the uremic milieu on endothelial morphology and cell junction's proteins. We evaluated (i) serum levels of inflammatory biomarkers in a cohort of chronic kidney disease (CKD) patients and the expression of VE-cadherin and Zonula Occludens-1 (ZO-1) junction proteins on endothelial cells (ECs) of arteries removed from CKD patients during renal transplant; (ii) ECs morphology in vitro under different uremic conditions, and (iii) the impact of uremic toxins p-cresyl sulfate (PCS), indoxyl sulfate (IS), and inorganic phosphate (Pi) as well as of total uremic serum on VE-cadherin and ZO-1 gene and protein expression in cultured ECs. We found that the uremic arteries had lost their intact and continuous endothelial morphology, with a reduction in VE-cadherin and ZO-1 expression. In cultured ECs, both VE-cadherin and ZO-1 protein expression decreased, mainly after exposure to Pi and uremic serum groups. VE-cadherin mRNA expression was reduced while ZO-1 was increased after exposure to PCS, IS, Pi, and uremic serum. Our findings show that uremia alters cell-to-cell junctions leading to an increased endothelial damage. This gives a new perspective regarding the pathophysiological role of uremia in intercellular junctions and opens new avenues to improve cardiovascular outcomes in CKD patients.
Assuntos
Antígenos CD/metabolismo , Caderinas/metabolismo , Células Endoteliais/fisiologia , Junções Intercelulares/fisiologia , Artéria Renal/fisiopatologia , Insuficiência Renal Crônica/fisiopatologia , Uremia/fisiopatologia , Proteína da Zônula de Oclusão-1/metabolismo , Linhagem Celular , Cresóis/farmacologia , Células Endoteliais/efeitos dos fármacos , Feminino , Humanos , Indicã/farmacologia , Masculino , Pessoa de Meia-Idade , Fosfatos/farmacologia , Artéria Renal/metabolismo , Insuficiência Renal Crônica/sangue , Ésteres do Ácido Sulfúrico/farmacologia , Toxinas Biológicas/farmacologia , Uremia/sangueRESUMO
Uremic toxin (UT) retention in chronic kidney disease (CKD) affects biological systems. We aimed to identify the associations between UT, inflammatory biomarkers and biomarkers of the uremic cardiovascular response (BUCVR) and their impact on cardiovascular status as well as their roles as predictors of outcome in CKD patients. CKD patients stages 3, 4 and 5 (n = 67) were recruited and UT (indoxyl sulfate/IS, p-cresil sulfate/pCS and indole-3-acetic acid/IAA); inflammatory biomarkers [Interleukin-6 (IL-6), high sensitivity C reactive protein (hsCRP), monocyte chemoattractant protein-1 (MCP-1), soluble vascular adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble Fas (sFas)] and BUCVRs [soluble CD36 (sCD36), soluble receptor for advanced glycation end products (sRAGE), fractalkine] was measured. Patients were followed for 5.2 years and all causes of death was used as the primary outcome. Artery segments collected at the moment of transplantation were used for the immunohistochemistry analysis in a separate cohort. Estimated glomerular filtration rate (eGFR), circulating UT, plasma biomarkers of systemic and vascular inflammation and BUCVR were strongly interrelated. Patients with plaque presented higher signs of UT-induced inflammation and arteries from CKD patients presented higher fractalkine receptor (CX3CR1) tissue expression. Circulating IS (p = 0.03), pCS (p = 0.007), IL-6 (p = 0.026), sFas (p = 0.001), sCD36 (p = 0.01) and fractalkine (p = 0.02) were independent predictors of total mortality risk in CKD patients. Our results reinforce the important role of uremic toxicity in the pathogenesis of cardiovascular disease (CVD) in CKD patients through an inflammatory pathway.
Assuntos
Doenças Cardiovasculares/metabolismo , Cresóis/sangue , Indicã/sangue , Ácidos Indolacéticos/sangue , Inflamação/metabolismo , Insuficiência Renal Crônica/metabolismo , Ésteres do Ácido Sulfúrico/sangue , Toxinas Biológicas/sangue , Uremia/metabolismo , Adulto , Idoso , Biomarcadores/metabolismo , Antígenos CD36/metabolismo , Doenças Cardiovasculares/fisiopatologia , Citocinas/metabolismo , Feminino , Taxa de Filtração Glomerular , Humanos , Inflamação/fisiopatologia , Masculino , Pessoa de Meia-Idade , Artéria Renal/metabolismo , Insuficiência Renal Crônica/fisiopatologia , Uremia/fisiopatologiaRESUMO
BACKGROUND: Activated cardiac fibroblasts (CFs), preglomerular vascular smooth muscle cells (PGVSMCs), and glomerular mesangial cells (GMCs) proliferate, cause hypertrophy, and produce collagen; in this way, activated CFs contribute to cardiac fibrosis, and activated PGVSMCs and GMCs promote renal fibrosis. In heart and kidney diseases, SDF-1α (stromal cell-derived factor 1α; endogenous CXCR4 [C-X-C motif chemokine receptor 4] receptor agonist) levels are often elevated; therefore, it is important to know whether and how the SDF-1α/CXCR4 axis activates CFs, PGVSMCs, or GMCs. METHODS AND RESULTS: Here we investigated whether SDF-1α activates CFs, PGVSMCs, and GMCs to proliferate, hypertrophy, or produce collagen. DPP4 (dipeptidyl peptidase 4) inactivates SDF-1α and previous experiments show that growth-promoting peptides have greater effects in cells from genetically-hypertensive animals. Therefore, we performed experiments in the absence and presence of sitagliptin (DPP4 inhibitor) and in cells from normotensive Wistar-Kyoto rats and spontaneously hypertensive rats. Our studies show (1) that spontaneously hypertensive and Wistar-Kyoto rat CFs, PGVSMCs, and GMCs express CXCR4 receptors and DPP4 activity; (2) that chronic treatment with physiologically relevant concentrations of SDF-1α causes concentration-dependent increases in the proliferation (cell number) and hypertrophy (3H-leucine incorporation) of and collagen production (3H-proline incorporation) by CFs, PGVSMCs, and GMCs; (3) that sitagliptin augments these effects of SDF-1α; (4) that interactions between SDF-1α and sitagliptin are greater in spontaneously hypertensive rat cells; (5) that CXCR4 antagonism (AMD3100) blocks all effects of SDF-1α; and (6) that SDF-1α/CXCR4 signal transduction likely involves the RACK1 (receptor for activated C kinase 1)/Gßγ/PLC (phospholipase C)/PKC (protein kinase C) signaling complex. CONCLUSIONS: The SDF-1α/CXCR4 axis drives proliferation and hypertrophy of and collagen production by CFs, PGVSMCs, and GMCs, particularly in cells from genetically hypertensive animals and when DPP4 is inhibited.
Assuntos
Cardiomiopatia Hipertrófica/genética , Quimiocina CXCL12/genética , Colágeno/biossíntese , Regulação da Expressão Gênica , Células Mesangiais/patologia , Músculo Liso Vascular/patologia , Miocárdio/patologia , Animais , Western Blotting , Cardiomiopatia Hipertrófica/metabolismo , Cardiomiopatia Hipertrófica/patologia , Proliferação de Células , Células Cultivadas , Quimiocina CXCL12/biossíntese , Modelos Animais de Doenças , Fibroblastos/metabolismo , Fibroblastos/patologia , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Masculino , Células Mesangiais/metabolismo , Microvasos/metabolismo , Microvasos/patologia , Músculo Liso Vascular/metabolismo , Miocárdio/metabolismo , RNA/genética , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Reação em Cadeia da Polimerase em Tempo Real , Receptores CXCR4/biossíntese , Receptores CXCR4/genética , Artéria Renal/metabolismo , Artéria Renal/patologiaRESUMO
Accumulating evidence from clinical and experimental studies indicates that the incretin glucagon-like peptide-1 (GLP-1) elicits blood-pressure lowering effects via its diuretic, natriuretic and vasodilatory properties. The present study investigated whether acute infusion of GLP-1 induces diuresis and natriuresis in spontaneously hypertensive rats (SHRs). Additionally, we examined whether GLP-1 influences the vascular reactivity of the renal arteries of normotensive and hypertensive rats and elucidated the underlying mechanisms. We found that the increase in urinary output and urinary sodium excretion in response to systemic infusion of GLP-1 for 30min in SHRs was much less pronounced than in normotensive rats. The diuretic and natriuretic actions of GLP-1 in normotensive rats were accompanied by increases in GFR and RBF and a reduction in RVR through activation of the cAMP signaling pathway. However, no changes in renal hemodynamics were observed in SHRs. Similarly, GLP-1 induced an endothelium-independent relaxation effect in the renal arteries of normotensive rats, whereas the renal vasculature of SHRs was unresponsive to this vasodilator. The absence of a GLP-1-induced renal artery vasodilator effect in SHRs was associated with lower expression of the GLP-1 receptor, blunted GLP-1-induced increases in cAMP production and higher activity and expression of the GLP-1 inactivating enzyme dipeptidyl peptidase IV relative to the renal arteries of normotensive rats. Collectively, these results demonstrate that the renal acute responses to GLP-1 are attenuated in SHRs. Thus, chronic treatment with incretin-based agents may rely upon the upregulation of GLP-1/GLP-1 receptor signaling in the kidneys of hypertensive patients and experimental models.
Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Peptídeo 1 Semelhante ao Glucagon/farmacologia , Receptor do Peptídeo Semelhante ao Glucagon 1/genética , Hipertensão/fisiopatologia , Natriurese/efeitos dos fármacos , Artéria Renal/efeitos dos fármacos , Animais , AMP Cíclico/metabolismo , Hipertensão/genética , Hipertensão/metabolismo , Hipertensão/patologia , Masculino , Ratos , Artéria Renal/metabolismo , Artéria Renal/fisiopatologia , Transdução de Sinais/efeitos dos fármacosRESUMO
Increased vascular matrix metalloproteinases (MMPs) levels play a role in late phases of hypertensive vascular remodeling. However, no previous study has examined the time course of MMPs in the various phases of two-kidney, one-clip hypertension (2K1C). We examined structural vascular changes, collagen and elastin content, vascular oxidative stress, and MMPs levels/activities during the development of 2K1C hypertension. Plasma angiotensin converting enzyme (ACE) activity was measured to assess renin-angiotensin system activation. Sham or 2K1C hypertensive rats were studied after 2, 4, 6, and 10weeks of hypertension. Systolic blood pressure (SBP) was monitored weekly. Morphometry of structural changes in the aortic wall was studied in hematoxylin/eosin, orcein and picrosirius red sections. Aortic NADPH activity and superoxide production was evaluated. Aortic gelatinolytic activity was determined by in situ zymography, and MMP-2, MMP-14, and tissue inhibitor of MMPs (TIMP)-2 levels were determined by gelatin zymography, immunofluorescence and immunohistochemistry. 2K1C hypertension was associated with increased ACE activity, which decreased to normal after 10 weeks. We found increased aortic collagen and elastin content in the early phase of hypertension, which were associated with vascular hypertrophy, increased vascular MMP-2 and MMP-14 (but not TIMP-2) levels, and increased gelatinolytic activity, possibly as a result of increased vascular NADPH oxidase activity and oxidative stress. These results indicate that vascular remodeling of renovascular hypertension is an early process associated with early increases in MMPs activities, enhanced matrix deposition and oxidative stress. Using antioxidants or MMPs inhibitors in the early phase of hypertension may prevent the vascular alterations of hypertension.
Assuntos
Hipertensão Renovascular/patologia , Metaloproteinase 14 da Matriz/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Angiotensina II/metabolismo , Animais , Aorta Torácica/enzimologia , Aorta Torácica/fisiopatologia , Pressão Sanguínea , Colágeno/metabolismo , Elastina/metabolismo , Ativação Enzimática , Imunofluorescência , Hipertensão Renovascular/metabolismo , Imuno-Histoquímica , Masculino , Inibidores de Metaloproteinases de Matriz , NADPH Oxidases/metabolismo , Estresse Oxidativo , Inibidores de Proteases/farmacologia , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Artéria Renal/metabolismo , Artéria Renal/fisiopatologia , Fatores de Tempo , Inibidor Tecidual de Metaloproteinase-2/metabolismoRESUMO
BACKGROUND: Cardiovascular disease in chronic kidney disease (CKD) has peculiar characteristics. The aim of this study was to analyze atherosclerosis, vascular calcification and nitration in arteries from CKD patients. METHODS: External iliac and renal artery segments from 27 stage 5 CKD patients and 25 donor controls, respectively, were collected during the transplantation procedure. RESULTS: CKD patients presented a significantly higher degree of lesion. In a large proportion (72%) of CKD patients, we observed vascular calcifications. Immunohistochemistry for nitrotyrosine revealed a significant increase in nitrotyrosine production in arteries from CKD patients compared with control donors. In addition, within CKD patients, nitrotyrosine staining was significantly stronger in arteries with media calcification when compared with arteries without media calcification. CONCLUSION: The arteriopathy in the CKD patients appears in an early age and seems to be distinct from the arteriopathy of the general population, especially due to intense calcification and vascular oxidative stress.
Assuntos
Falência Renal Crônica/metabolismo , Falência Renal Crônica/patologia , Proteínas/metabolismo , Calcificação Vascular/patologia , Adulto , Aterosclerose/patologia , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Artéria Renal/metabolismo , Artéria Renal/patologia , Fatores de Risco , Tirosina/análogos & derivados , Tirosina/metabolismoRESUMO
The aim of this study was to investigate the effects of astaxanthin-enriched diet on blood pressure, cardiac hypertrophy, both vascular structure and function and superoxide ((*)O(2-)) production in spontaneously hypertensive rats (SHR). Twelve-week-old SHR were treated for 8 weeks with an astaxanthin-enriched diet (75 or 200mg/kg body weight per day). Systolic blood pressure was monitorized periodically during the study by the tail cuff method. At the end of the study animals were sacrificed and heart, kidneys and aorta were removed. Left ventricular weight/body weight ratio was used as left ventricular hypertrophy index (LVH). Vascular function and structure were studied in conductance (aortic rings) and resistance (renal vascular bed) arteries. Also (*)O(2-) production was evaluated by lucigenin-enhanced chemiluminescence. Systolic blood pressure was lower in astaxanthin-treated groups than the control group from the first week of treatment, and LVH was significantly reduced. Astaxanthin improved endothelial function on resistance arteries, but had no effect on aorta. These effects were accompanied by a decrease in oxidative stress and improvements in NO bioavailability. Taken together, these results show that diet supplemented with astaxanthin has beneficial effects on hypertension, by decreasing blood pressure values, improving cardiovascular remodeling and oxidative stress.
Assuntos
Anti-Hipertensivos/administração & dosagem , Aorta/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Dieta , Hipertensão/tratamento farmacológico , Hipertrofia Ventricular Esquerda/prevenção & controle , Artéria Renal/efeitos dos fármacos , Animais , Aorta/metabolismo , Aorta/fisiopatologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiopatologia , Hipertensão/genética , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/genética , Hipertrofia Ventricular Esquerda/metabolismo , Hipertrofia Ventricular Esquerda/fisiopatologia , Masculino , NADPH Oxidases/metabolismo , Óxido Nítrico/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Endogâmicos SHR , Artéria Renal/metabolismo , Artéria Renal/fisiopatologia , Superóxidos/metabolismo , Fatores de Tempo , Resistência Vascular/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia , Xantofilas/administração & dosagemRESUMO
Mounting evidence indicates that structural and functional vascular changes associated with two-kidney, one-clip (2K-1C) hypertension result, at least in part, from altered activity of matrix metalloproteinases (MMPs). Because MMPs are upregulated by increased formation of reactive oxygen species (ROS), we hypothesized that antioxidant approaches could attenuate the increases in MMP-2 expression/activity and the vascular dysfunction and remodeling associated with 2K-1C hypertension. Sham-operated or 2K-1C hypertensive rats were treated with tempol 18 mg/kg/day or apocyanin 25 mg/kg/day (or vehicle). Systolic blood pressure was monitored weekly. After 8 weeks of treatment, aortic rings were isolated to assess endothelium-dependent and -independent relaxation. Quantitative morphometry of structural changes in the aortic wall was studied in hematoxylin/eosin sections. Aortic and systemic ROS levels were measured using dihydroethidine and thiobarbituric acid-reactive substances, respectively. Aortic MMP-2 levels and activity were determined by gelatin and in situ zymography, fluorimetry, and immunohistochemistry. Tempol and apocyanin attenuated 2K-1C hypertension (181+/-20.8 and 192+/-17.6 mm Hg, respectively, versus 213+/-18 mm Hg in hypertensive controls; both p<0.05) and prevented the reduction in endothelium-dependent vasorelaxation found in 2K-1C rats. Tempol, but not apocyanin (p>0.05), prevented the vascular remodeling found in 2K-1C rats (all p<0.01). Tempol was more effective than apocyanin in attenuating hypertension-induced increases in oxidative stress (both p<0.05), MMP-2 levels, and MMP-2 activity in hypertensive rats (all p<0.05). Our results suggest that antioxidant approaches decrease MMP-2 upregulation and attenuate the vascular dysfunction and remodeling during 2K-1C hypertension.