RESUMO
BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare, progressive, fatal vascular disorder. Genetic predisposition plays vital roles in the development of PAH, with most mutations being identified in genes involved in the transforming growth factor beta (TGF-ß) signaling pathways. Defects in the BMP9 gene have been documented in hereditary hemorrhagic telangiectasia (HHT), the most common inherited vascular disorder, which is occasionally associated with PAH. Selective enhancement of endothelial BMPR2 with BMP9 reverses pulmonary arterial hypertension. CASE PRESENTATION: We report the case of a 5-year-old Hispanic boy who was diagnosed with severe PAH and right heart failure at 3 years of age. During his stay in the pediatric intensive care unit, treatment was initiated with inhaled nitric oxide and intravenous epoprostenol; he subsequently was transitioned to treprostinil, sildenafil, and prophylactic enoxaparin. Now, two years later, the child is asymptomatic on sildenafil, bosentan, subcutaneous treprostinil, and warfarin. Genetic screening revealed a novel homozygous nonsense mutation in the BMP9 gene (c.76C > T; p.Gln26Ter). The child had no telangiectasias or arteriovenous malformations; family history also was negative. Subsequent parental testing showed both parents were heterozygous for the same mutation, indicating that the child inherited the BMP9 mutant allele from each parent. CONCLUSION: To our knowledge, this is the first report of a BMP9 mutation in a patient with PAH. The homozygous nonsense mutation may account for the early onset and severity of PAH in this patient and also fit the 'two-hit' model we proposed previously. The absence of clinical symptoms for PAH in the parents may be due to incomplete penetrance or various expressivities of the BMP9 mutations. Our study expands the spectrum of phenotypes related to BMP9 mutations.
Assuntos
Fatores de Diferenciação de Crescimento/genética , Hipertensão Pulmonar/genética , Americanos Mexicanos/genética , Anticoagulantes/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Bosentana , Pré-Escolar , Códon sem Sentido , Epoprostenol/análogos & derivados , Epoprostenol/uso terapêutico , Fator 2 de Diferenciação de Crescimento , Homozigoto , Humanos , Hipertensão Pulmonar/tratamento farmacológico , Masculino , Citrato de Sildenafila/uso terapêutico , Sulfonamidas/uso terapêutico , Vasodilatadores/uso terapêutico , Varfarina/uso terapêuticoRESUMO
Rapamycin at high doses (2-10 mg/kg body weight) inhibits mammalian target of rapamycin complex 1 (mTORC1) and protein synthesis in mice. In contrast, low doses of rapamycin (10 µg/kg) increase mTORC1 activity and protein synthesis in skeletal muscle. Similar changes are found with SLF (synthetic ligand for FKBP12, which does not inhibit mTORC1) and in mice with a skeletal muscle-specific FKBP12 deficiency. These interventions also increase Ca(2+) influx to enhance refilling of sarcoplasmic reticulum Ca(2+) stores, slow muscle fatigue, and increase running endurance without negatively impacting cardiac function. FKBP12 deficiency or longer treatments with low dose rapamycin or SLF increase the percentage of type I fibers, further adding to fatigue resistance. We demonstrate that FKBP12 and its ligands impact multiple aspects of muscle function.
Assuntos
Ligantes , Músculo Esquelético/crescimento & desenvolvimento , Sirolimo/administração & dosagem , Proteína 1A de Ligação a Tacrolimo/metabolismo , Animais , Sinalização do Cálcio/efeitos dos fármacos , Relação Dose-Resposta a Droga , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Complexos Multiproteicos , Contração Muscular/efeitos dos fármacos , Músculo Esquelético/metabolismo , Ligação Proteica , Biossíntese de Proteínas/efeitos dos fármacos , Retículo Sarcoplasmático/efeitos dos fármacos , Retículo Sarcoplasmático/metabolismo , Serina-Treonina Quinases TOR , Proteína 1A de Ligação a Tacrolimo/química , Proteína 1A de Ligação a Tacrolimo/genéticaRESUMO
The pan-cancer initiative aims to study the origin patterns of cancer cell, the processes of carcinogenesis, and the signaling pathways from a perspective that spans across different types of cancer. The construction of the pan-cancer related gene regulatory network is helpful to excavate the commonalities in regulatory relationships among different types of cancers. It also aids in understanding the mechanisms behind cancer occurrence and development, which is of great scientific significance for cancer prevention and treatment. In light of the high dimension and large sample size of pan-cancer omics data, a causal pan-cancer gene regulation network inference algorithm based on stochastic complexity is proposed. With the network construction strategy of local first and then global, the stochastic complexity is used in the conditional independence test and causal direction inference for the candidate adjacent node set of the target nodes. This approach aims to decrease the time complexity and error rate of causal network learning. By applying this algorithm to the sample data of seven types of cancers in the TCGA database, including breast cancer, lung adenocarcinoma, and so on, the pan-cancer related causal regulatory networks are constructed, and their biological significance is verified. The experimental results show that this algorithm can eliminate the redundant regulatory relationships effectively and infer the pan-cancer regulatory network more accurately (https://github.com/LindeEugen/CNI-SC).
Assuntos
Algoritmos , Redes Reguladoras de Genes , Neoplasias , Humanos , Redes Reguladoras de Genes/genética , Neoplasias/genética , Biologia Computacional/métodos , Regulação Neoplásica da Expressão Gênica , Transdução de Sinais/genética , Processos EstocásticosRESUMO
OBJECTIVE: To determine the impact of hematopoietic deletion of nuclear factor- (erythroid-derived 2) like 2 factor (Nrf2) on the development of atherosclerosis and liver injury in an obese, hypercholesterolemic mouse model. METHODS AND RESULTS: Two-month-old male low-density lipoprotein receptor-deficient mice were lethally irradiated and transplanted with either wild type or Nrf2-deficient (Nrf2(-/-)) bone marrow cells. At 3 months of age, mice were placed on an obesogenic high-fat diet (HFD), high-cholesterol diet for 7 months. Despite no differences in body weight, body fat percentage, liver fat, plasma glucose, lipids, or insulin, the HFD-fed Nrf2(-/-) bone marrow recipients had increased proinflammatory vascular gene expression, a significant increase in atherosclerosis area (18% versus 28%; P=0.018) and lesion complexity, and a marked increase in liver fibrosis. The acceleration of vascular and liver injury may arise from enhanced macrophage migration, inflammation, and oxidative stress resulting from myeloid Nrf2 deficiency. CONCLUSIONS: Myeloid-derived Nrf2 activity attenuates atherosclerosis development and liver inflammation and fibrosis associated with obesity. Prevention of oxidative stress in macrophage and other myeloid lineage cells may be an important therapeutic target to reduce inflammation-driven complications of obesity.
Assuntos
Aterosclerose/epidemiologia , Deleção de Genes , Hipercolesterolemia/complicações , Cirrose Hepática/epidemiologia , Células Mieloides/metabolismo , Fator 2 Relacionado a NF-E2/deficiência , Obesidade/complicações , Animais , Aterosclerose/metabolismo , Aterosclerose/fisiopatologia , Transplante de Medula Óssea , Movimento Celular/fisiologia , Comorbidade , Modelos Animais de Doenças , Hipercolesterolemia/epidemiologia , Cirrose Hepática/metabolismo , Cirrose Hepática/fisiopatologia , Macrófagos/metabolismo , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Obesidade/epidemiologia , Estresse Oxidativo/fisiologia , Receptores de LDL/deficiência , Receptores de LDL/genética , Receptores de LDL/metabolismo , Fatores de RiscoRESUMO
Lysophosphatidic acid (LPA) has been implicated as causative in phenotypic modulation (PM) of cultured vascular smooth muscle cells (VSMC) in their transition to the dedifferentiated phenotype. We evaluated the contribution of the three major LPA receptors, LPA1 and LPA2 GPCR and PPARgamma, on PM of VSMC. Expression of differentiated VSMC-specific marker genes, including smooth muscle alpha-actin, smooth muscle myosin heavy chain, calponin, SM-22alpha, and h-caldesmon, was measured by quantitative real-time PCR in VSMC cultures and aortic rings kept in serum-free chemically defined medium or serum- or LPA-containing medium using wild-type C57BL/6, LPA1, LPA2, and LPA1&2 receptor knockout mice. Within hours after cells were deprived of physiological cues, the expression of VSMC marker genes, regardless of genotype, rapidly decreased. This early PM was neither prevented by IGF-I, inhibitors of p38, ERK1/2, or PPARgamma nor significantly accelerated by LPA or serum. To elucidate the mechanism of PM in vivo, carotid artery ligation with/without replacement of blood with Krebs solution was used to evaluate contributions of blood flow and pressure. Early PM in the common carotid was induced by depressurization regardless of the presence/absence of blood, but eliminating blood flow while maintaining blood pressure or after sham surgery elicited no early PM. The present results indicate that LPA, serum, dissociation of VSMC, IGF-I, p38, ERK1/2, LPA1, and LPA2 are not causative factors of early PM of VSMC. Tensile stress generated by blood pressure may be the fundamental signal maintaining the fully differentiated phenotype of VSMC.
Assuntos
Diferenciação Celular , Lisofosfolipídeos/metabolismo , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/metabolismo , Animais , Aorta/citologia , Apoptose , Pressão Sanguínea/fisiologia , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Fator de Crescimento Insulin-Like I/antagonistas & inibidores , Masculino , Camundongos , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Músculo Liso Vascular/efeitos dos fármacos , Miócitos de Músculo Liso/efeitos dos fármacos , Fenótipo , Fatores de TempoRESUMO
MicroRNAs (miRNAs) are a recently discovered class of endogenous, small, noncoding RNAs that regulate about 30% of the encoding genes of the human genome. However, the role of miRNAs in vascular disease is currently completely unknown. Using microarray analysis, we demonstrated for the first time that miRNAs are aberrantly expressed in the vascular walls after balloon injury. The aberrantly expressed miRNAs were further confirmed by Northern blot and quantitative real-time polymerase chain reaction. Modulating an aberrantly overexpressed miRNA, miR-21, via antisense-mediated depletion (knock-down) had a significant negative effect on neointimal lesion formation. In vitro, the expression level of miR-21 in dedifferentiated vascular smooth muscle cells was significantly higher than that in fresh isolated differentiated cells. Depletion of miR-21 resulted in decreased cell proliferation and increased cell apoptosis in a dose-dependent manner. MiR-21-mediated cellular effects were further confirmed in vivo in balloon-injured rat carotid arteries. Western blot analysis demonstrated that PTEN and Bcl-2 were involved in miR-21-mediated cellular effects. The results suggest that miRNAs are novel regulatory RNAs for neointimal lesion formation. MiRNAs may be a new therapeutic target for proliferative vascular diseases such as atherosclerosis, postangioplasty restenosis, transplantation arteriopathy, and stroke.
Assuntos
Artérias Carótidas/metabolismo , MicroRNAs/metabolismo , MicroRNAs/fisiologia , Músculo Liso Vascular/metabolismo , Oligonucleotídeos Antissenso/farmacologia , Túnica Íntima/metabolismo , Angioplastia com Balão , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Sequência de Bases , Northern Blotting , Artérias Carótidas/citologia , Artérias Carótidas/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Células Cultivadas , Modelos Animais de Doenças , Regulação para Baixo , Masculino , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Dados de Sequência Molecular , Músculo Liso Vascular/efeitos dos fármacos , Proteínas , Ratos , Ratos Sprague-Dawley , Túnica Íntima/efeitos dos fármacos , Túnica Íntima/crescimento & desenvolvimentoRESUMO
In the automatic analysis system of the kidney-tissue image, boundary enhancement for glomerulus area is a vital step. Complex characteristics of kidney-tissue image leads to the difficulty in boundary features description. This paper suggests a kind of feature template under the special boundary definition. A nonlinear threshold surface is constructed by neural network, then the proper surface can be selected to enhance boundary with the influence of error permissibility being taken into account. Experimental results indicate that this learning method with error permissibility can enhance the boundary of glomerulus and suppress noises at the same time, so it can obtain good processed effects and have a fine performance highly adaptive to various sample images.
Assuntos
Processamento de Imagem Assistida por Computador , Glomérulos Renais/patologia , Redes Neurais de Computação , HumanosRESUMO
Andersen-Tawil syndrome (ATS) is an autosomal dominant, multisystem channelopathy characterized by periodic paralysis, ventricular arrhythmias and distinctive dysmorphic facial or skeletal features. The disorder displays marked intrafamilial variability and incomplete penetrance. Myasthenia gravis (MG) is an autoimmune disorder that demonstrates progressive fatigability, in which the nicotinic acetylcholine receptor (AChR) at neuromuscular junctions is the primary autoantigen. The present study reports a rare case of a 31-year-old woman with a history of morbid obesity and periodic weakness, who presented with hemodynamic instability, cardiogenic shock and facial anomalies. Laboratory results revealed hypokalemia and an elevated anti-AChR antibody expression levels. Electrocardiography demonstrated prolonged QT-interval, ST-elevation, and subsequent third-degree atrioventricular block. Neurological examination revealed bilateral ptosis, horizontal diplopia, dysarthria and generalized weakness. No mutations in the potassium channel inwardly rectifying subfamily J member 2 gene were detected in the present case. The patient was treated with oral potassium supplementation and an acetylcholinesterase inhibitor (pyridostigmine), after which the symptoms were improved. To the best of our knowledge, the present case report was the first to describe concomitant presentation of both ATS and MG, which represents a diagnostic and therapeutic challenge.
RESUMO
OBJECTIVE: To study the effect of icariin on vascular endothelial cells (VECs) injury induced by hypoxia. METHODS: The hypoxia-ischemia model was established. The effect of icariin on injury of VECs activity induced by hypoxia was determined by MTT assay. The levels of malondialdehyde (MDA), superoxide dismutase (SOD) and lactate dehydrogenase (LDH) activity in cell homogenate were measured with corresponding kit. Effect of icariin on cells apoptosis induced by hypoxia was determined by Hoechst 33342 fluorescent staining, cell ultrastructure observation under transmission electron microscopy and analysis on gene fragmentation by flow cytometry and DNA gel electrophoresis. RESULTS: ICA could inhibit the hypoxia induced VECs reduction, suppress LDH activity, reduce the MDA production, and enhance SOD activity under hypoxia. Hypoxia could induce VECs apoptosis, revealed chromation condensed in nuclei with the fragments arranged along the nuclear membrane. DNA gel electrophoresis showed typical ladder strands of DNA. Cells displayed a typical sub-diploid peak in flow cytometry. ICA could significantly inhibit the hypoxia induced apoptosis of VECs. CONCLUSION: ICA has the protective effect on hypoxia injured VECs, which may be related to its effect of anti-apoptosis, anti-lipid peroxidation and SOD activity enhancing.
Assuntos
Apoptose/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Células Endoteliais/patologia , Flavonoides/farmacologia , Hipóxia Celular , Células Cultivadas , Humanos , Substâncias Protetoras/farmacologia , Superóxido Dismutase/metabolismo , Veias Umbilicais/patologiaRESUMO
OBJECTIVE: To study the effects of XueFuZhuYu Decoction (XFZYD) on collagen synthesis and proliferation of cardiac fibroblasts and provide academic bases of remedying kinds of heart disease aroused by proliferation of cardiac fibroblasts. METHODS: By adding medicine directly and serum pharmacological method. RESULTS: Compared with the control group, 1 g/ml XFZYD(dilution 1:80) and 10 percent serum of rat contained XFZYD could significantly inhibit the collagen synthesis and the proliferation of cardiac fibroblasts. Moreover, 1 g/ml XFZYD(dilution 1:80) could significantly affect collagen secrtion of cardiac fibroblasts (P < 0.05), up to 17.9%. CONCLUSION: XFZYD could inhibit both proliferation and collagen secretion of cardiac fibroblasts. It could resist cardiac muscle fibrosis.
Assuntos
Colágeno/biossíntese , Medicamentos de Ervas Chinesas/farmacologia , Fibroblastos/metabolismo , Miocárdio/metabolismo , Plantas Medicinais/química , Angelica sinensis/química , Animais , Animais Recém-Nascidos , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Colágeno/metabolismo , Medicamentos de Ervas Chinesas/isolamento & purificação , Masculino , Miocárdio/citologia , Prunus/química , Ratos , Ratos Sprague-Dawley , Rehmannia/químicaRESUMO
Pulmonary arterial hypertension (PAH) is a devastating disease characterized by abnormal remodeling of small, peripheral pulmonary arteries. Germline mutations in the bone morphogenetic protein receptor type 2 (BMPR2) gene are a major risk factor for developing PAH. At present, the correlation between the BMPR2 mutation and the patient's prognosis remains controversial despite several investigations. In this study, we explored the functional effects of four BMPR2 mutations to dissect the functional significance of the BMPR2 gene defect. Cellular immunofluorescence assay of four mutants (Tyr67Cys, Thr268fs, Ser863Asn, and Gln433X) revealed that the BMPR2 protein containing Thr268fs, Ser863Asn, or Gln433X exhibited abnormal subcellular localization. The BrdU incorporation and TUNEL assay suggested that any of the BMPR2 mutations Thr268fs, Ser863Asn, or Gln433X could improve endothelial cell apoptosis and decrease cell proliferation. All of the four mutants could inhibit nitric oxide (NO) synthesis in HLMVE cells, and ET-1 levels increased in the cells transfected with mutant Ser863Asn. Our results will improve the understanding of the genotype-phenotype correlations and mechanisms associated with BMPR2 mutations.
Assuntos
Receptores de Proteínas Morfogenéticas Ósseas Tipo II/genética , Células Endoteliais/metabolismo , Endotelina-1/genética , Mutação , Apoptose/genética , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/metabolismo , Proliferação de Células , Células Cultivadas , Células Endoteliais/ultraestrutura , Endotelina-1/metabolismo , Regulação da Expressão Gênica , Humanos , Marcação In Situ das Extremidades Cortadas , Pulmão/metabolismo , Pulmão/ultraestrutura , Óxido Nítrico/biossíntese , Plasmídeos/química , Plasmídeos/metabolismo , Transdução de Sinais , TransfecçãoRESUMO
Scopolamine hydrobromide (SH)-loaded microparticles were prepared from a colloidal fluid containing ionotropic-gelated chitosan nanoparticles using a spray-drying method. The spray-dried microparticles were then formulated into orally disintegrating tablets (ODTs) using a wet granulation tablet formation process. A drug entrapment efficiency of about 90% (w/w) and loading capacity of 20% (w/w) were achieved for the microparticles, which ranged from 2 µm to 8 µm in diameter. Results of disintegration tests showed that the formulated ODTs could be completely dissolved within 45 seconds. Drug dissolution profiles suggested that SH is released more slowly from tablets made using the microencapsulation process compared with tablets containing SH that is free or in the form of nanoparticles. The time it took for 90% of the drug to be released increased significantly from 3 minutes for conventional ODTs to 90 minutes for ODTs with crosslinked microparticles. Compared with ODTs made with noncrosslinked microparticles, it was thus possible to achieve an even lower drug release rate using tablets with appropriate chitosan crosslinking. Results obtained indicate that the development of new ODTs designed with crosslinked microparticles might be a rational way to overcome the unwanted taste of conventional ODTs and the side effects related to SH's intrinsic characteristics.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Microesferas , Nanopartículas/química , Escopolamina/química , Administração Oral , Adulto , Análise de Variância , Quitosana/química , Humanos , Masculino , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanopartículas/ultraestrutura , Nanotecnologia , Tamanho da Partícula , Escopolamina/administração & dosagem , Escopolamina/farmacocinética , Solubilidade , Comprimidos/administração & dosagem , Comprimidos/química , Comprimidos/farmacocinética , PaladarRESUMO
To control the release rate and mask the bitter taste, cetirizine dihydrochloride (CedH) was entrapped within chitosan nanoparticles (CS-NPs) using an ionotropic gelation process, followed by microencapsulation to produce CS matrix microparticles using a spray-drying method. The aqueous colloidal CS-NPs dispersions with a drug encapsulation efficiency (EE) of <15%, were then spray dried to produce a powdered nanoparticles-in-microparticles system with an EE of >70%. The resultant spherical CS microparticles had a smooth surface, were free of organic solvent residue and showed a diameter range of 0.5~5 µm. The in vitro drug release properties of CedH encapsulated microparticles showed an initial burst effect during the first 2 h. Drug release from the matrix CS microparticles could be retarded by the crosslinking agent pentasodium tripolyphosphate or the wall material. The technique of 'ionotropic gelation' combined with 'spray-drying' could be applicable for preparation of CS nanoparticlesin-microparticles drug delivery systems. CS-NPs based microparticles might provide a potential micro-carrier for oral administration of the freely water-soluble drug--CedH.
Assuntos
Cetirizina/química , Quitosana/química , Sistemas de Liberação de Medicamentos , Antagonistas não Sedativos dos Receptores H1 da Histamina/química , Nanopartículas/química , Administração Oral , Cetirizina/administração & dosagem , Composição de Medicamentos , Excipientes/química , Antagonistas não Sedativos dos Receptores H1 da Histamina/administração & dosagem , Microesferas , Tamanho da Partícula , Polifosfatos/química , Pós , Solubilidade , Percepção GustatóriaAssuntos
Receptores de Proteínas Morfogenéticas Ósseas Tipo II/genética , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/genética , Canal de Potássio Kv1.5/genética , Mutação/genética , Índice de Gravidade de Doença , Adolescente , Adulto , Feminino , Humanos , Hipertensão Pulmonar/fisiopatologia , Masculino , LinhagemRESUMO
MicroRNAs (miRNAs) are a recently discovered class of endogenous, small, noncoding RNAs that regulate gene expression. Although miRNAs are highly expressed in the heart, their roles in heart diseases are currently unclear. Using microarray analysis designed to detect the majority of mammalian miRNAs identified thus far, we demonstrated that miRNAs are aberrantly expressed in hypertrophic mouse hearts. The time course of the aberrant miRNA expression was further identified in mouse hearts at 7, 14, and 21 days after aortic banding. Nineteen of the most significantly dysregulated miRNAs were further confirmed by Northern blot and/or real-time polymerase chain reaction, in which miR-21 was striking because of its more than fourfold increase when compared with the sham surgical group. Similar aberrant expression of the most up-regulated miRNA, miR-21, was also found in cultured neonatal hypertrophic cardiomyocytes stimulated by angiotensin II or phenylephrine. Modulating miR-21 expression via antisense-mediated depletion (knockdown) had a significant negative effect on cardiomyocyte hypertrophy. The results suggest that miRNAs are involved in cardiac hypertrophy formation. miRNAs might be a new therapeutic target for cardiovascular diseases involving cardiac hypertrophy such as hypertension, ischemic heart disease, valvular diseases, and endocrine disorders.
Assuntos
Cardiomegalia/genética , Coração/fisiologia , MicroRNAs/metabolismo , Angiotensina II/metabolismo , Animais , Cardiomegalia/metabolismo , Cardiomegalia/patologia , Células Cultivadas , Perfilação da Expressão Gênica , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Miócitos Cardíacos/citologia , Miócitos Cardíacos/fisiologia , Análise de Sequência com Séries de Oligonucleotídeos , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Atherosclerosis, which is characterized by neointima formation, is an inflammatory disease. However, there is no inflammatory product-elicited neointimal model to support the causal role of inflammation in atherogenesis. We reported previously that leukocyte-derived MPO induces vascular injury responses such as endothelial dysfunction. We now test the role of MPO in inflammatory neointima formation. We infused temporarily isolated rat common carotid arteries with MPO (200 nM) and incubated for 1 h. We found that although MPO itself did not induce any neointima formation 2 wk after treatment, in the presence of its substrate, hydrogen peroxide, MPO was able to elicit neointimal hyperplasia. We further confirmed that MPO-induced neointimal hyperplasia is mediated by its product, hypochlorous acid (HOCl). HOCl elicited apoptosis both in intima and media followed by vascular proliferative response and resulted in neointima formation with a heterogeneous cell population. Both histological and functional features of HOCl-treated vessels are similar to those in atherosclerotic lesions. To our knowledge, this is the first direct in vivo demonstration of neointimal formation induced by a product of the inflammatory cascade. The results suggest that MPO may be a mediator for pathological neointima growth. This novel neointimal model could be useful for studying inflammation and atherosclerosis.
Assuntos
Peroxidase/metabolismo , Túnica Íntima/patologia , Túnica Íntima/fisiopatologia , Túnica Média/patologia , Túnica Média/fisiopatologia , Animais , Apoptose/efeitos dos fármacos , Aterosclerose/patologia , Aterosclerose/fisiopatologia , Artérias Carótidas/efeitos dos fármacos , Artérias Carótidas/metabolismo , Artérias Carótidas/patologia , Artérias Carótidas/fisiopatologia , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Endotélio Vascular/fisiopatologia , Hiperplasia/metabolismo , Hiperplasia/patologia , Hiperplasia/fisiopatologia , Ácido Hipocloroso/metabolismo , Ácido Hipocloroso/farmacologia , Ratos , Ratos Sprague-Dawley , Fatores de Tempo , Túnica Íntima/efeitos dos fármacos , Túnica Íntima/metabolismo , Túnica Média/efeitos dos fármacos , Túnica Média/metabolismoRESUMO
Reduced nitric oxide (NO) bioavailability and impaired vascular function are the key pathological characteristics of inflammatory diseases such as atherosclerosis. We have recently found that leukocyte-derived hypochlorous acid is able to react with the nitric-oxide synthase (NOS) substrate L-arginine to produce chlorinated L-arginine (cl-L-Arg). Interestingly, cl-L-Arg potently inhibits the formation of NO metabolites in cultured endothelial cells. It is unknown whether cl-L-Arg has a direct inhibitory effect on endothelial NOS (eNOS). In addition, the effect of cl-L-Arg on the other NOS isoforms, neuronal NOS (nNOS) and inducible NOS (iNOS), is also unknown. Therefore, we designed the current study to test the effects of cl-L-Arg on eNOS, nNOS, and iNOS. Using recombinant NOS, we found that cl-L-Arg had a direct inhibitory effect on the activity of NOS. The effect of cl-L-Arg on NOS activity is nonselective, as all three NOS isoforms were inhibited with a similar IC(50). We further determined the effect of cl-L-Arg on the three NOS isoforms at the tissue level. The results demonstrated that cl-L-Arg potently inhibited all three NOS isoform-mediated vessel reactivities, as well as the NOS signaling molecule cGMP. Cl-L-Arg might serve as a novel endogenous NOS inhibitor and an important mediator for vascular dysfunction under inflammatory conditions such as atherosclerosis. Blocking cl-L-Arg formation may be a new therapeutic approach to cardiovascular diseases.