RESUMO
INTRODUCTION: In men, lower urinary tract symptoms (LUTS) are primarily attributed to benign prostatic hyperplasia (BPH). Therapeutic options are targeted to relax prostate smooth muscle and/or reduce prostate enlargement. Areas covered: This article reviews the major preclinical and clinical data on PDE5 inhibitors with a specific focus on tadalafil. It includes details of the role of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) - PDE5 pathway in the LUT organs (bladder and prostate) in addition to the available data on tadalafil in patients with LUTS secondary to BPH with or without erectile dysfunction (ED). Expert opinion: Preclinical and clinical data have clearly demonstrated that PDE5 inhibitors induce bladder and prostate relaxation, which contributes to the improvement seen in storage symptoms in both animal models of bladder and prostate hypercontractility. Tadalafil is effective both as a monotherapy and add-on therapy in patients with LUTS secondary to BPH. Furthermore, as LUTS-BPH and ED are urological disorders that commonly coexist in aging men, tadalafil is more advantageous than α1-adrenoceptors and should be used as the first option. Tadalafil is a safe and tolerable therapy and unlike α1- adrenoceptors and 5-alpha reductase inhibitors, which can cause sexual dysfunctions, tadalafil improves sexual function.
Assuntos
Sintomas do Trato Urinário Inferior/tratamento farmacológico , Hiperplasia Prostática/tratamento farmacológico , Tadalafila/uso terapêutico , Inibidores de 5-alfa Redutase/uso terapêutico , Animais , Disfunção Erétil/tratamento farmacológico , Humanos , Masculino , Inibidores da Fosfodiesterase 5/uso terapêutico , Disfunções Sexuais Fisiológicas/tratamento farmacológico , Resultado do TratamentoRESUMO
INTRODUCTION: Tumor necrosis factor-alpha (TNF-α) exerts a critical role in inflammatory events through two distinct receptors, TNFR1 and TNFR2. Platelets have been recognized as important inflammatory cells, but little is known about the effects of TNF-α on the platelet activity. OBJECTIVES: In the present study we have studied the role of TNF-α on ADP-induced platelet aggregation and its downstream signaling (c-Src and fibrinogen receptor phosphorylation, cytosolic Ca2+ mobilization, cAMP and cGMP levels and cell viability). METHODS AND RESULTS: Washed rat platelets were incubated with TNF-α (1-3000â¯pg/ml) for different time-periods (5-60â¯min) before the addition of ADP (5⯵M) to induce platelet aggregation. TNF-α concentration- and time-dependently inhibits ADP-induced aggregation, which was significantly prevented by incubation with the non-selective TNF-α receptor antagonist R7050. TNF-α (300â¯pg/ml, 30â¯min) decreases thrombin-induced elevation of cytosolic Ca++ levels by 2.2- fold compared to untreated platelets. TNF-α decreases the cAMP levels, while significantly increases the intracellular cyclic cGMP levels. However, the pre-incubation of platelets with the guanylyl cyclase inhibitor ODQ, despite decreasing the cGMP levels, does not modify the inhibitory effect of TNF-α on ADP-induced platelet aggregation. Additionally, western blotting analysis showed that TNF-α significantly reduced (Tyr 416)-c-Src and (Tyr773)-ß3 subunit of αIIbß3 integrin phosphorylation. TNF-α does not affect the platelet viability in any condition tested. CONCLUSION: Therefore, our results show that TNF-α negatively modulates ADP-induced aggregation via TNFR1/TNFR2 receptors by reducing cytosolic Ca++ levels and by inhibiting c-Src and fibrinogen receptor activation, which take place through cAMP- and cGMP-independent mechanisms.
Assuntos
Plaquetas/metabolismo , Cálcio/metabolismo , Integrina beta3/metabolismo , Agregação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Glicoproteína IIb da Membrana de Plaquetas/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Plaquetas/citologia , GMP Cíclico/metabolismo , Citosol/metabolismo , Masculino , Fosforilação , Ratos WistarRESUMO
OBJECTIVES: Activators of soluble guanylyl cyclase (sGC) act preferentially in conditions of enzyme oxidation or haem group removal. This study was designed to investigate the effects of the sGC activator BAY 60-2770 in murine airways inflammation and human eosinophil chemotaxis. METHODS: C57Bl/6 mice treated or not with BAY 60-2770 (1 mg/kg/day, 14 days) were intranasally challenged with ovalbumin (OVA). At 48 h, bronchoalveolar lavage fluid (BALF) was performed, and circulating blood, bone marrow and lungs were obtained. Human eosinophils purified from peripheral blood were used to evaluate the cell chemotaxis. RESULTS: OVA-challenge promoted marked increases in eosinophil number in BAL, lung tissue, circulating blood and bone marrow, all of which were significantly reduced by BAY 60-2770. The IL-4 and IL-5 levels in BALF were significantly reduced by BAY 60-2770. Increased protein expression of iNOS, along with decreases of expression of sGC (α1 and ß1 subunits) and cGMP levels were detected in lung tissue of OVA-challenged mice. BAY 60-2770 fully restored to baseline the iNOS and sGC subunit expressions, and cGMP levels. In human isolated eosinophils, BAY 60-2770 (1-5 µM) had no effects on the cGMP levels and eotaxin-induced chemotaxis; however, prior incubation with ODQ (10 µM) markedly elevated the BAY 60-2770-induced cyclic GMP production, further inhibiting the eosinophil chemotaxis. CONCLUSIONS: BAY 60-2770 reduces airway eosinophilic inflammation and rescue the sGC levels. In human eosinophils under oxidized conditions, BAY 60-2770 elevates the cGMP levels causing cell chemotaxis inhibition. BAY 60-2770 may reveal a novel therapeutic target for asthma treatment.
Assuntos
Benzoatos/farmacologia , Compostos de Bifenilo/farmacologia , Eosinófilos/efeitos dos fármacos , Hidrocarbonetos Fluorados/farmacologia , Inflamação/tratamento farmacológico , Guanilil Ciclase Solúvel/efeitos dos fármacos , Animais , Antiasmáticos/farmacologia , Asma/tratamento farmacológico , Asma/imunologia , Líquido da Lavagem Broncoalveolar/imunologia , Quimiotaxia/efeitos dos fármacos , GMP Cíclico/metabolismo , Modelos Animais de Doenças , Eosinófilos/metabolismo , Humanos , Inflamação/imunologia , Inflamação/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ovalbumina/imunologia , Guanilil Ciclase Solúvel/metabolismoRESUMO
Nitric oxide (NO)-cyclic 3'-5' guanosine monophosphate (cGMP) signaling plays a critical role on smooth muscle tone, platelet activity, cardiac contractility, renal function and fluid balance, and cell growth. Studies of the 1990s established endothelium dysfunction as one of the major causes of cardiovascular diseases. Therapeutic strategies that benefit NO bioavailability have been applied in clinical medicine extensively. Basic and clinical studies of cGMP regulation through activation of soluble guanylyl cyclase (sGC) or inhibition of cyclic nucleotide phosphodiesterase type 5 (PDE5) have resulted in effective therapies for pulmonary hypertension, erectile dysfunction, and more recently benign prostatic hyperplasia. This section reviews (1) how endothelial dysfunction and NO deficiency lead to cardiovascular diseases, (2) how soluble cGMP regulation leads to beneficial effects on disorders of the circulation system, and (3) the epigenetic regulation of NO-sGC pathway components in the cardiovascular system. In conclusion, the discovery of the NO-cGMP pathway revolutionized the comprehension of pathophysiological mechanisms involved in cardiovascular and other diseases. However, considering the expression "from bench to bedside" the therapeutic alternatives targeting NO-cGMP did not immediately follow the marked biochemical and pathophysiological revolution. Some therapeutic options have been effective and released on the market for pulmonary hypertension and erectile dysfunction such as inhaled NO, PDE5 inhibitors, and recently sGC stimulators. The therapeutic armamentarium for many other disorders is expected in the near future. There are currently numerous active basic and clinical research programs in universities and industries attempting to develop novel therapies for many diseases and medical applications.
Assuntos
GMP Cíclico/metabolismo , Endotélio/metabolismo , Óxido Nítrico/metabolismo , Animais , Epigênese Genética , Humanos , Transdução de Sinais , Guanilil Ciclase Solúvel/metabolismoRESUMO
OBJECTIVES: To compare nitric oxide (NO) serum levels in women with and without preeclampsia. METHODS: 106 women were classified into preeclampsia group (n = 40) and normotensive group (n = 66). NO content was measured in the serum. Clinical and laboratorial data were recorded for comparison. RESULTS: Preeclampsia presented a significant increase in nitrate and NOx levels compared to the control group. Uric acid, gestational age, systolic and diastolic blood pressure, and creatinine showed correlation with nitrates and NOx. CONCLUSION: Increase of NO was observed in preeclampsia women. Failure in the mechanism of action, dependent on cyclic GMP, may justify this finding.
Assuntos
Nitratos/sangue , Óxido Nítrico/sangue , Pré-Eclâmpsia/sangue , Adolescente , Adulto , Pressão Sanguínea/fisiologia , Feminino , Idade Gestacional , Humanos , Nitritos/sangue , Gravidez , Ácido Úrico/sangue , Adulto JovemRESUMO
Chronic neuroinflammation is a common characteristic of neurodegenerative diseases, and lipopolysaccharide (LPS) signaling is linked to glutamate-nitric oxide-Na,K-ATPase isoforms pathway in central nervous system (CNS) and also causes neuroinflammation. Intermittent fasting (IF) induces adaptive responses in the brain that can suppress inflammation, but the age-related effect of IF on LPS modulatory influence on nitric oxide-Na,K-ATPase isoforms is unknown. This work compared the effects of LPS on the activity of α1,α2,3 Na,K-ATPase, nitric oxide synthase gene expression and/or activity, cyclic guanosine monophosphate, 3-nitrotyrosine-containing proteins, and levels of thiobarbituric acid-reactive substances in CNS of young and older rats submitted to the IF protocol for 30 days. LPS induced an age-related effect in neuronal nitric oxide synthase activity, cyclic guanosine monophosphate, and levels of thiobarbituric acid-reactive substances in rat hippocampus that was linked to changes in α2,3-Na,K-ATPase activity, 3-nitrotyrosine proteins, and inducible nitric oxide synthase gene expression. IF induced adaptative cellular stress-response signaling pathways reverting LPS effects in rat hippocampus of young and older rats. The results suggest that IF in both ages would reduce the risk for deficits on brain function and neurodegenerative disorders linked to inflammatory response in the CNS.
Assuntos
Envelhecimento/metabolismo , Jejum/fisiologia , Hipocampo/metabolismo , Lipopolissacarídeos/toxicidade , Estresse Oxidativo/fisiologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Animais , Hipocampo/patologia , Masculino , Doenças Neurodegenerativas/etiologia , Doenças Neurodegenerativas/prevenção & controle , Inflamação Neurogênica/etiologia , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/metabolismo , Nucleotídeos Cíclicos/metabolismo , Ratos Wistar , Tiobarbitúricos/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismoRESUMO
Nitric oxide (NO) is a very reactive molecule, and its short half-life would make it virtually invisible until its discovery. NO activates soluble guanylyl cyclase (sGC), increasing 3',5'-cyclic guanosine monophosphate levels to activate PKGs. Although NO triggers several phosphorylation cascades due to its ability to react with Fe II in heme-containing proteins such as sGC, it also promotes a selective posttranslational modification in cysteine residues by S-nitrosylation, impacting on protein function, stability, and allocation. In the central nervous system (CNS), NO synthesis usually requires a functional coupling of nitric oxide synthase I (NOS I) and proteins such as NMDA receptors or carboxyl-terminal PDZ ligand of NOS (CAPON), which is critical for specificity and triggering of selected pathways. NO also modulates CREB (cAMP-responsive element-binding protein), ERK, AKT, and Src, with important implications for nerve cell survival and differentiation. Differences in the regulation of neuronal death or survival by NO may be explained by several mechanisms involving localization of NOS isoforms, amount of NO being produced or protein sets being modulated. A number of studies show that NO regulates neurotransmitter release and different aspects of synaptic dynamics, such as differentiation of synaptic specializations, microtubule dynamics, architecture of synaptic protein organization, and modulation of synaptic efficacy. NO has also been associated with synaptogenesis or synapse elimination, and it is required for long-term synaptic modifications taking place in axons or dendrites. In spite of tremendous advances in the knowledge of NO biological effects, a full description of its role in the CNS is far from being completely elucidated.
Assuntos
Sistema Nervoso Central/fisiologia , Óxido Nítrico/metabolismo , Transdução de Sinais/fisiologia , Animais , Sistema Nervoso Central/crescimento & desenvolvimento , Plasticidade Neuronal/fisiologia , Neurônios/fisiologia , Neurotransmissores/fisiologiaRESUMO
INTRODUCTION: Cardiovascular and endocrine-metabolic diseases associated with increased oxidative stress such as obesity lead to erectile dysfunction (ED). Activators of soluble guanylyl cyclase (sGC) such as BAY 60-2770 reactivate the heme-oxidized sGC in vascular diseases. AIM: This study aimed to evaluate the effects of 2-week oral intake with BAY 60-2270 on a murine model of obesity-associated ED. METHODS: C57BL/6 male mice were fed for 12 weeks with standard chow or high-fat diet. Lean and obese mice were treated with BAY 60-2770 (1 mg/kg/day, 2 weeks). MAIN OUTCOME MEASURES: Measurements of intracavernosal pressure (ICP), along with acetylcholine (10(-9) to 10(-5) M) and electrical field stimulation (EFS; 4-10 Hz)-induced corpus cavernosum relaxations in vitro, were obtained. Levels of cyclic guanosine monophosphate (cGMP), reactive oxygen species (ROS), and sGC protein expressions in cavernosal tissues were measured. RESULTS: Cavernous nerve stimulation caused frequency-dependent ICP increases, which were significantly lower in obese compared with lean mice (P < 0.05). Two-week therapy with BAY 60-2770 fully reversed the decreased ICP in obese group. Acetylcholine-induced cavernosal relaxations were 45% lower (P < 0.001) in obese mice, which were fully restored by BAY 60-2770 treatment. Likewise, the EFS-induced relaxations in obese mice were restored by BAY 60-2770. Basal cGMP content in erectile tissue was 68% lower (P < 0.05) in obese mice, an effect normalized by BAY 60-2770. Levels of ROS were 52% higher (P < 0.05) whereas protein expression of α1 sGC subunit was reduced in cavernosal tissue of obese mice, both of which were normalized by BAY 60-2770. In lean group, BAY 60-2770 did not significantly affect any functional, biochemical, or molecular parameter analyzed. CONCLUSIONS: Two-week therapy with BAY 60-2770 restores the erectile function in obese mice that is associated with reduced ROS levels, up-regulation of α1 sGC subunit, and increased cGMP levels in the erectile tissue.
Assuntos
Benzoatos/administração & dosagem , Compostos de Bifenilo/administração & dosagem , Ativadores de Enzimas/administração & dosagem , Disfunção Erétil/tratamento farmacológico , Disfunção Erétil/fisiopatologia , Hidrocarbonetos Fluorados/administração & dosagem , Receptores Citoplasmáticos e Nucleares/agonistas , Animais , GMP Cíclico/metabolismo , Dieta Hiperlipídica/efeitos adversos , Disfunção Erétil/enzimologia , Disfunção Erétil/etiologia , Guanilato Ciclase/genética , Guanilato Ciclase/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Obesidade/complicações , Ereção Peniana/efeitos dos fármacos , Pênis/irrigação sanguínea , Espécies Reativas de Oxigênio/metabolismo , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Guanilil Ciclase Solúvel , Regulação para CimaRESUMO
New bioactive N-acylhydrazone derivatives synthesized from safrole previously have been found to promote intense vasodilation and antihypertensive activity. In this study, we describe the synthesis and the cardiovascular effects of the new N-acylhydrazone derivative (E)-N-methyl-N'-(thiophen-3-ylmethylene)benzo[d][1,3]dioxole-5-carbohydrazide (LASSBio-1289). Thoracic aorta and left papillary muscles from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were prepared for isometric tension recording. LASSBio-1289 promoted relaxation of endothelium-intact and denuded aortic rings with respective pIC50 (-log IC50) values of 5.07 ± 0.09 and 4.26 ± 0.09 (P < 0.001) for WKY rats and 5.43 ± 0.05 and 5.58 ± 0.07 (P > 0.05) for SHR. The vasodilator activity of LASSBio-1289 was increased in the KCl-contracted aorta. LASSBio-1289 attenuated the contracture elicited by Ca(2+) in depolarized aorta from both WKY rats and SHR. In endothelium-intact aorta from WKY rats, LASSBio-1289-induced relaxation was unchanged after incubation with propranolol, ZM 241385, atropine, diphenhydramine, and HOE140, but was significantly reduced by L-NAME and ODQ. LASSBio-1289 decreased papillary muscles contractility only at concentrations above 200 µm. Acute intravenous injection of LASSBio-1289 (3 mg/kg) produced a significant hypotensive response in SHR but not in WKY rats, suggesting its antihypertensive profile. The antihypertensive effect was also observed in SHR during 14 days of intraperitoneal and oral administration. In conclusion, our data demonstrated that LASSBio-1289 induces both endothelium-independent vasorelaxation involving the inhibition of Ca(2+) influx through L-type Ca(2+) channels in aorta from WKY rats and SHR, and endothelium-dependent relaxation mediated by the NO/cyclic GMP pathway in WKY rats.
Assuntos
Anti-Hipertensivos/farmacologia , Benzodioxóis/farmacologia , Canais de Cálcio Tipo L/metabolismo , Hidrazonas/farmacologia , Vasodilatadores/farmacologia , Animais , Aorta Torácica/efeitos dos fármacos , Aorta Torácica/metabolismo , Cálcio/metabolismo , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Masculino , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Músculos Papilares/efeitos dos fármacos , Músculos Papilares/metabolismo , Cloreto de Potássio/metabolismo , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Vasodilatação/efeitos dos fármacosRESUMO
PURPOSE: To assess the viability of McFarlane skin flaps in rats with administration of sildenafil. METHODS: Twenty Wistar rats were distributed into two groups: Control (dorsal skin flap, subdermal application of saline solution at 0.9%) and Study (dorsal skin flap, subdermal application of sildenafil). Seven days after the surgery, flaps were photographed and graphically rendered. Then, they were analyzed with AutoCAD software. Three biopsies (proximal, medial and distal) of each flap were collected for histological analysis. RESULTS: Macroscopic analysis showed that animals of the study group had greater necrotic areas (p=0.003) in the dorsal skin flaps. Additionally, histological analysis of the distal third of these flaps showed a tendency to less granulated tissue formation in animals treated with sildenafil. CONCLUSION: Sildenafil subdermally was associated with lower viability of the random skin flap in rats.(AU)
OBJETIVO: Avaliar a viabilidade de retalhos cutâneos de ratos à McFarlane após a administração de sildenafil. MÉTODOS: Vinte ratos Wistar foram distribuídos em dois grupos: Controle (confecção do retalho cutâneo dorsal, aplicação subdérmica de solução salina a 0,9%) e Estudo (confecção do retalho cutâneo dorsal, aplicação subdérmica de sildenafil). Sete dias após a operação, os retalhos foram fotografados e representados graficamente, para serem analisados com o programa AutoCad. Três biópsias (cranial, média e caudal) foram coletadas de cada retalho, para análise histológica. RESULTADOS: A análise macroscópica evidenciou que os animais do grupo Estudo apresentaram maiores áreas de necrose (p=0,003) nos retalhos cutâneos dorsais. Além disso, a análise histológica dos terços distais dos retalhos mostrou uma tendência à formação de menos tecido de granulação nos animais que receberam o sildenafil. CONCLUSÃO: O sildenafil subdérmico esteve associado com uma pior viabilidade tecidual dos retalhos cutâneos dorsais de ratos.(AU)
Assuntos
Ratos , Retalhos Cirúrgicos , Cicatrização , Biópsia , Óxido NítricoRESUMO
PURPOSE: To assess the viability of McFarlane skin flaps in rats with administration of sildenafil. METHODS: Twenty Wistar rats were distributed into two groups: Control (dorsal skin flap, subdermal application of saline solution at 0.9 percent) and Study (dorsal skin flap, subdermal application of sildenafil). Seven days after the surgery, flaps were photographed and graphically rendered. Then, they were analyzed with AutoCAD software. Three biopsies (proximal, medial and distal) of each flap were collected for histological analysis. RESULTS: Macroscopic analysis showed that animals of the study group had greater necrotic areas (p=0.003) in the dorsal skin flaps. Additionally, histological analysis of the distal third of these flaps showed a tendency to less granulated tissue formation in animals treated with sildenafil. CONCLUSION: Sildenafil subdermally was associated with lower viability of the random skin flap in rats.
OBJETIVO: Avaliar a viabilidade de retalhos cutâneos de ratos à McFarlane após a administração de sildenafil. MÉTODOS: Vinte ratos Wistar foram distribuídos em dois grupos: Controle (confecção do retalho cutâneo dorsal, aplicação subdérmica de solução salina a 0,9 por cento) e Estudo (confecção do retalho cutâneo dorsal, aplicação subdérmica de sildenafil). Sete dias após a operação, os retalhos foram fotografados e representados graficamente, para serem analisados com o programa AutoCad. Três biópsias (cranial, média e caudal) foram coletadas de cada retalho, para análise histológica. RESULTADOS: A análise macroscópica evidenciou que os animais do grupo Estudo apresentaram maiores áreas de necrose (p=0,003) nos retalhos cutâneos dorsais. Além disso, a análise histológica dos terços distais dos retalhos mostrou uma tendência à formação de menos tecido de granulação nos animais que receberam o sildenafil. CONCLUSÃO: O sildenafil subdérmico esteve associado com uma pior viabilidade tecidual dos retalhos cutâneos dorsais de ratos.
Assuntos
Animais , Feminino , Ratos , /farmacologia , Piperazinas/farmacologia , Pele/efeitos dos fármacos , Sulfonas/farmacologia , Retalhos Cirúrgicos/patologia , Sobrevivência de Tecidos/efeitos dos fármacos , Biópsia , Necrose/patologia , Purinas/farmacologia , Ratos Wistar , Pele/patologia , Pele/cirurgia , CicatrizaçãoRESUMO
O nitric oxide (NO, óxido nítrico) é um mediador endógeno vasoativo que contribui para a homeostase vascular pulmonar. O NO é produzido por três isoformas das nitric oxide synthases (NOS, óxido nítrico sintases)-NOS neuronial (nNOS); NOS induzida (iNOS); e NOS endotelial (eNOS)-estando as três presentes no pulmão. Estudos que utilizaram inibidores farmacológicos ou camundongos knockout têm demonstrado que o NO derivado da eNOS desempenha importantes papéis ao modular o tônus vascular pulmonar e atenuar a hipertensão pulmonar. Por outro lado, estudos focados no papel da iNOS têm mostrado que essa isoforma contribui para a fisiopatologia da lesão pulmonar aguda e da síndrome do desconforto respiratório agudo. Esta revisão objetivou delinear o papel desempenhado pelo NO no controle da circulação pulmonar, tanto em condições fisiológicas como fisiopatológicas. Além disso, revisamos as evidências de que a via L-arginina-NO-guanosina monofosfato cíclico seja um importante alvo farmacológico para a terapia de doenças vasculares pulmonares.
Nitric oxide (NO) is an endogenous vasoactive compound that contributes to pulmonary vascular homeostasis and is produced by three nitric oxide synthase (NOS) isoforms-neuronal NOS (nNOS); inducible NOS (iNOS); and endothelial NOS (eNOS)-all three of which are present in the lung. Studies using pharmacological inhibitors or knockout mice have shown that eNOS-derived NO plays an important role in modulating pulmonary vascular tone and attenuating pulmonary hypertension. However, studies focusing on the role of iNOS have shown that this isoform contributes to the pathophysiology of acute lung injury and acute respiratory distress syndrome. This review aimed at outlining the role played by NO in the control of pulmonary circulation, both under physiological and pathophysiological conditions. In addition, we review the evidence that the L-arginine-NO-cyclic guanosine monophosphate pathway is a major pharmacological target in the treatment of pulmonary vascular diseases.
Assuntos
Animais , Humanos , Camundongos , Hipertensão Pulmonar/fisiopatologia , Óxido Nítrico/fisiologia , Circulação Pulmonar/fisiologia , Arginina/fisiologia , Ensaios Clínicos como Assunto , GMP Cíclico/fisiologia , Camundongos Knockout , Óxido Nítrico Sintase Tipo I/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Óxido Nítrico/biossínteseRESUMO
Guanylin and uroguanylin are small cysteine-rich peptides involved in the regulation of fluid and electrolyte homeostasis through binding and activation of guanylyl cyclases signaling molecules expressed in intestine and kidney. Guanylin is less potent than uroguanylin as a natriuretic agent and is degraded in vitro by chymotrypsin due to unique structural features in the bioactive moiety of the peptide. Thus, the aim of this study was to verify whether or not guanylin is degraded by chymotrypsin-like proteases present in the kidney brush-border membranes. The isolated perfused rat kidney assay was used in this regard. Guanylin (0.2 µM) induced no changes in kidney function. However, when pretreated by the black-eyed pea trypsin and chymotrypsin inhibitor (BTCI - 1.0 µM; guanylin - 0.2 µM) it promoted increases in urine flow (deltaUF of 0.25 ± 0.09 mL.g-1/min, P < 0.05) and Na+ excretion ( percent delta ENa+ of 18.20 ± 2.17, P < 0.05). BTCI (1.0 µM) also increased percentENa+ (from 22.8 ± 1.30 to 34.4 ± 3.48, P < 0.05, 90 minutes). Furthermore, BTCI (3.0 µM) induced increases in glomerular filtration rate (GFR; from 0.96 ± 0.02 to 1.28 0.02 mL.g-1/min, P < 0.05, 60 minutes). The present paper strongly suggests that chymotrypsin-like proteases play a role in renal metabolism of guanylin and describes for the first time renal effects induced by a member of the Bowman-Birk family of protease inhibitors.
Guanilina e uroguanilina são peptídeos pequenos, ricos em cisteína, envolvidos na regulação da homeostase de fluidos e eletrólitos através da ligação e ativação da guanilato ciclase expressa no intestino e nos rins. A guanilina é menos potente do que a uroguanilina como agente natriurético e é degradada in vitro pela quimiotripsina devido a características estruturais únicas no domínio bioativo do peptídeo. Portanto o objetivo deste trabalho foi verificar se a guanilina é degradada por proteases tipo quimiotripsina, presentes na membrana da borda em escova dos rins. Para esta investigação, foi usado o modelo do rim isolado de rato perfundido. A Guanilina (0,2 µM) não induziu mudanças na função renal. Entretanto, quando pré-tratada com inibidor de tripsina e de quimiotripsina de black-eyed pea (BTCI - 1,0 µM; guanilina - 0,2 µM) promoveu um aumento no fluxo urinário (deltaUF de 0,25 ± 0,09 mL.g-1/min, P < 0,05) e na excreção de Na+ ( por centoDENa+ de 18,20 ± 2,17, P < 0,05). BTCI (1,0 µM) também aumenta por centoENa+ (de 22,8 ± 1,30 a 34,4 ± 3,48, P < 0,0590 minutos). Além disto, BTCI (3,0 µM) induziu um aumento da taxa de filtração glomerular (GFR; de 0,96 ± 0,02 para 1,28 ± 0,02 mL.g-1/min, P < 0,05, 60 minutos). O presente trabalho sugere fortemente que proteases semelhantes à quimiotripsina desempenham um papel no metabolismo renal de guanilinas e descreve, pela primeira vez, os efeitos renais induzidos por um membro da família de inibidores de proteases do tipo Bowman-Birk.
Assuntos
Animais , Feminino , Masculino , Ratos , Hormônios Gastrointestinais/farmacologia , Glomérulos Renais/efeitos dos fármacos , Túbulos Renais/efeitos dos fármacos , Natriurese/efeitos dos fármacos , Peptídeos Natriuréticos/farmacologia , Inibidores de Proteases/farmacologia , Relação Dose-Resposta a Droga , Glomérulos Renais/fisiologia , Túbulos Renais/fisiologia , Natriurese/fisiologia , Proteínas de Plantas/farmacologia , Ratos Endogâmicos WKYRESUMO
Guanylin and uroguanylin are small cysteine-rich peptides involved in the regulation of fluid and electrolyte homeostasis through binding and activation of guanylyl cyclases signaling molecules expressed in intestine and kidney. Guanylin is less potent than uroguanylin as a natriuretic agent and is degraded in vitro by chymotrypsin due to unique structural features in the bioactive moiety of the peptide. Thus, the aim of this study was to verify whether or not guanylin is degraded by chymotrypsin-like proteases present in the kidney brush-border membranes. The isolated perfused rat kidney assay was used in this regard. Guanylin (0.2 µM) induced no changes in kidney function. However, when pretreated by the black-eyed pea trypsin and chymotrypsin inhibitor (BTCI - 1.0 µM; guanylin - 0.2 µM) it promoted increases in urine flow (deltaUF of 0.25 ± 0.09 mL.g-1/min, P 0.05) and Na+ excretion (% delta ENa+ of 18.20 ± 2.17, P 0.05). BTCI (1.0 µM) also increased %ENa+ (from 22.8 ± 1.30 to 34.4 ± 3.48, P 0.05, 90 minutes). Furthermore, BTCI (3.0 µM) induced increases in glomerular filtration rate (GFR; from 0.96 ± 0.02 to 1.28 0.02 mL.g-1/min, P 0.05, 60 minutes). The present paper strongly suggests that chymotrypsin-like proteases play a role in renal metabolism of guanylin and describes for the first time renal effects induced by a member of the Bowman-Birk family of protease inhibitors.
Guanilina e uroguanilina são peptídeos pequenos, ricos em cisteína, envolvidos na regulação da homeostase de fluidos e eletrólitos através da ligação e ativação da guanilato ciclase expressa no intestino e nos rins. A guanilina é menos potente do que a uroguanilina como agente natriurético e é degradada in vitro pela quimiotripsina devido a características estruturais únicas no domínio bioativo do peptídeo. Portanto o objetivo deste trabalho foi verificar se a guanilina é degradada por proteases tipo quimiotripsina, presentes na membrana da borda em escova dos rins. Para esta investigação, foi usado o modelo do rim isolado de rato perfundido. A Guanilina (0,2 µM) não induziu mudanças na função renal. Entretanto, quando pré-tratada com inibidor de tripsina e de quimiotripsina de black-eyed pea (BTCI - 1,0 µM; guanilina - 0,2 µM) promoveu um aumento no fluxo urinário (deltaUF de 0,25 ± 0,09 mL.g-1/min, P 0,05) e na excreção de Na+ (%DENa+ de 18,20 ± 2,17, P 0,05). BTCI (1,0 µM) também aumenta %ENa+ (de 22,8 ± 1,30 a 34,4 ± 3,48, P 0,0590 minutos). Além disto, BTCI (3,0 µM) induziu um aumento da taxa de filtração glomerular (GFR; de 0,96 ± 0,02 para 1,28 ± 0,02 mL.g-1/min, P 0,05, 60 minutos). O presente trabalho sugere fortemente que proteases semelhantes à quimiotripsina desempenham um papel no metabolismo renal de guanilinas e descreve, pela primeira vez, os efeitos renais induzidos por um membro da família de inibidores de proteases do tipo Bowman-Birk.
RESUMO
CONTEXT AND OBJECTIVE: Nitric oxide has a pathophysiological role in modulating systemic changes associated with anaphylaxis. Nitric oxide synthase inhibitors may exacerbate bronchospasm in anaphylaxis and worsen clinical conditions, with limited roles in anaphylactic shock treatment. The aim here was to report an anaphylaxis case (not anaphylactic shock), reversed by methylene blue (MB), a guanylyl cyclase inhibitor. CASE REPORT: A 23-year-old female suddenly presented urticaria and pruritus, initially on her face and arms, then over her whole body. Oral antihistamine was administered initially, but without improvement in symptoms and signs until intravenous methylprednisolone 500 mg. Recurrence occurred after two hours, plus vomiting. Associated upper respiratory distress, pulmonary sibilance, laryngeal stridor and facial angioedema (including erythema and lip edema) marked the evolution. At sites with severe pruritus, petechial lesions were observed. The clinical situation worsened, with dyspnea, tachypnea, peroral cyanosis, laryngeal edema with severe expiratory dyspnea and deepening unconsciousness. Conventional treatment was ineffective. Intubation and ventilatory support were then considered, because of severe hypoventilation. But, before doing that, based on our previous experience, 1.5 mg/kg (120 mg) bolus of 4 percent MB was infused, followed by one hour of continuous infusion of another 120 mg diluted in dextrose 5 percent in water. Following the initial intravenous MB dose, the clinical situation reversed completely in less than 20 minutes, thereby avoiding tracheal intubation. CONCLUSION: Although the nitric oxide hypothesis for MB effectiveness discussed here remains unproven, our intention was to share our accumulated cohort experience, which strongly suggests MB is a lifesaving treatment for anaphylactic shock and/or anaphylaxis and other vasoplegic conditions.
CONTEXTO E OBJETIVO: O óxido nítrico (NO) tem papel fisiopatológico na modulação das alterações sistêmicas associadas à anafilaxia. Inibidores da sintase do NO podem exacerbar a broncoconstrição na anafilaxia e piorar as condições clínicas e têm um papel limitado no tratamento do choque anafilático. O objetivo deste relato foi o de apresentar um caso de anafilaxia (não-choque anafilático) revertido pela inibição da guanilato ciclase pelo azul de metileno. RELATO DE CASO: Mulher de 23 anos apresentou repentina urticária e prurido, inicialmente localizados na face e nos braços, que se estenderam para quase todo o corpo. Utilizou-se, inicialmente, anti-histamínico, mas pequena melhora só foi observada após o uso endovenoso de 500 mg metilprednisolona. Após duas horas, os sintomas voltaram acompanhados de vômitos. Observou-se dificuldade respiratória alta, sibilos respiratórios, estridores laríngeos, angioedema facial, incluindo eritema, edema de lábios e, nos locais de intenso prurido, observaram-se petéquias. O quadro agravou-se com dispnéia, taquipnéia, parestesia peroral, edema laríngeo, grave dispnéia expiratória com crescente perda da consciência. O tratamento convencional não foi efetivo. Considerou-se intubação pela grave hipoventilação. Com base em nossa prévia experiência, um bolo endovenoso de 1,5 mg/kg (120 mg) de azul de metileno a 4 por cento diluído em soro glicosado 5 por cento, seguido de outros 120 mg infundidos durante uma hora. Após a dose endovenosa inicial do azul de metileno, a situação clínica reverteu-se completamente, evitando-se a intubação traqueal. CONCLUSÃO: Embora a hipótese da eficácia da relação entre o óxido nítrico e o azul de metileno ainda esteja por ser provada, nossa intenção foi de compartilhar nossa experiência acumulada, que sugere fortemente que o azul de metileno seja um tratamento salvador de vidas para o choque anafilático e/ou anafilaxia e outras condições vasoplégicas.