21 |
Efeito antinociceptivo e antiinflamatório do extrato etanólico e da benzofenona 7-epiclusianona isolada de folhas de Garcinia brasiliensis Mart.(Clusiaceae)SANTA CECÍLIA, Flávia Viana 11 February 2011 (has links)
A espécie Garcinia brasiliensis, conhecida como "bacupari", é nativa da Amazônia e cultivada em todo o território brasileiro. Na medicina popular, suas folhas são utilizadas para tratar tumores, inflamações das vias urinárias e artrite, bem como para aliviar dores. Este trabalho foi conduzido para avaliar a atividade analgésica e antiinflamatória do extrato etanólico foliar (GbEE) e da 7-epiclusianona, uma benzofenona natural poliprenilada isolada de suas folhas, em modelos animais in vivo. A ação deste benzofenona também foi investigada em um ensaio antiinflamatório ex vivo, enfocando o “burst” respiratório de neutrófilos e as vias bioquímicas envolvidas. Foi constatada atividade atividade antiinflamatória tanto para GbEE v.o. ( 30, 100 3 300 mg /kg) como para 7-epiclusianona v.o.(5, 10 e 15mg/Kg) por reduzir o edema de pata induzido por carragenina e inibir o recrutamento de leucócitos na cavidade peritoneal. Além disso, através do modelo de indução de inflamação crônica foi observado uma redução estatisticamente significativa de formação do tecido granulomatoso. Por outro lado, efeito antinociceptivo periférico foi atribuído ao GbEE sugerindo ser mais eficaz contra dores inflamatórias, enquanto que para a benzofenona foi constatada tanto atividade antinociceptiva periférica como central, através de diferentes mecanismos. O composto 7-epiclusianona (10 a 100µg) também foi capaz de reduzir e até mesmo suprimir a liberação de ânion superóxido por fagócitos inflamatórios através de um mecanismo controlado pela fosforilação da proteína tirosina e pela estimulação direta da proteína quinase C, sugerindo novas abordagens terapêuticas para o tratamento de processos inflamatórios e desenvolvimento de novos fármacos. Os resultados mostraram atividades antiinflamatória e analgésica das folhas de G. brasiliensis e da benzofenona isolada, confirmando o uso tradicional dessa espécie para tratamento de dores e inflamações. / The species Garcinia brasiliensis, known as “bacupari”, is native to the Amazon and cultivated throughout Brazil. Their leaves are used in folk medicine to treat tumors, inflammation of the urinary tract and arthritis as well as to relief pain. This study was conducted to evaluate the anti-inflammatory and analgesic effects of the ethanolic extract of leaves (GbEE) and the 7-epiclusianone, a natural polyisoprenilated benzophenone isolated from G. brasiliensis, in several animal models. The action of the benzophenone was also investigated ex vivo throughout an anti-inflammatory assay, focusing neutrophil respiratory burst and the biochemical pathway. Antiinflammatory activity was found for both GbEE (30, 100 and 300 mg /kg) p.o. and for 7-epiclusianone (5, 10 and 15mg/kg) p.o. to reduce the paw edema induced by carrageenan and to inhibit leukocyte recruitment into the peritoneal cavity. In addition, through the induction model of chronic inflammation, was observed a statistically significant reduction of granulomatous tissue formation. Moreover, peripheral antinociceptive effect was attributed to GbEE suggesting that this extract could be more effective against inflammatory pain, whereas for benzophenone was verified both peripheral and central antinociceptive activity through different mechanisms.The compound 7-epiclusianone (10 to 100 μg) was also able to reduce and even suppress the release of superoxide anion by inflammatory phagocytes through a mechanism controlled by protein tyrosine phosphorylation and by direct stimulation of protein kinase C, suggesting new therapeutic approaches for the treatment of inflammatory processes and development of new drugs. So, it was demonstrated the anti-inflammatory and antinociceptive activities of the leaves of G. brasiliensis and the benzophenone isolated which supports previous claims of the traditional use of this species against inflammation and pain. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
|
22 |
Collaboration of human neutrophils and group IIA phospholipase A2 against Staphylococcus aureusFemling, Jon Kenneth 01 January 2007 (has links)
Neutrophils (PMN) and group IIA phospholipase A2 (gIIA PLA2) are components of the innate immune system mobilized to sites of invasion by microorganisms such as Staphylococcus aureus. Although accumulating coincidentally in vivo, the in vitro anti-staphylococcal activities of PMN and gIIA PLA2 have thus far been separately studied. The goal of this thesis was to study the collaborative activity of PMN and gIIA PLA2 against S. aureus.
We have identified and characterized the collaboration of PMN and gIIA PLA2 against S. aureus ingested by PMN. PMN induced conversion of bacterial phosphatidylglycerol into cardiolipin, but were unable to degrade S. aureus phospholipids without gIIA PLA2. PMN reduced by 10-fold the concentration of gIIA PLA2 needed to digest bacterial phospholipids alone.
In addition to increased phospholipid degradation, collaboration of PMN and gIIA PLA2 caused greater bacterial killing and greater loss of bacterial green fluorescent protein fluorescence. The collaboration of PMN and gIIA PLA2 against S. aureus is dependent on catalytic activity and is specific to gIIA PLA2 as related secretory PLA2, groups IB, V, and X, show little or no phospholipid degradation of S. aureus either alone or in the presence of PMN. Synergy of PMN and gIIA PLA2 requires a functional NADPH oxidase and phagocytosis. Although addition of gIIA PLA2 after phagocytosis causes some bacterial phospholipid degradation, the greatest effect is observed when gIIA PLA2 is added before phagocytosis.
An extracellular source of H2O2 can partially restore antibacterial activities to NADPH oxidase deficient PMN including the ability to collaborate with gIIA PLA2, supporting a role for reactive oxygen species in NADPH oxidase dependent antimicrobial functions of PMN. In contrast, iberiotoxin, an inhibitor of BK potassium channels had no effect of PMN antibacterial activities. Although H2O2 partially restored antibacterial activity to NADPH oxidase deficient PMN, extracellular H2O2 was not sufficient to increase S. aureus to gIIA PLA2 activity.
In summary, PMN and gIIA PLA2 collaborate against S. aureus. These findings revealed collaboration between cellular oxygen-dependent and extracellular oxygen-independent host defense systems that may be important in the ultimate resolution of S. aureus infections.
|
23 |
Neutrophil priming and host inflammation: The roles of NOX2 and toll-like receptorsWhitmore, Laura Christine 01 May 2014 (has links)
Neutrophils, essential innate immune cells, recognize danger signals through receptors on their surface. Upon receptor ligation, neutrophils may undergo priming, a process involving limited reactive oxygen species (ROS) generation and partial degranulation. Priming facilitates neutrophil migration and prepares the cell for an enhanced response to a secondary stimulus, including a spike in ROS generation by NADPH oxidase 2 (NOX2). It is well established that NOX2-derived oxidants are involved in pathogen killing and that off-target effects can cause host tissue damage; however, several lines of recent evidence also support an anti-inflammatory function for NOX2 oxidants. First, patients with chronic granulomatous disease exhibit sterile inflammatory phenomena. Second, neutrophils lacking NOX2 function (genetically or pharmacologically) have an inflammatory phenotype under resting conditions. Finally, NOX2-deficient mice exhibit enhanced localized inflammation in several disease models. The goals of this thesis were to investigate an anti-inflammatory function for NOX2 during systemic inflammation and to further elucidate mechanisms of neutrophil priming, with particular focus on priming through Toll-like receptor 2 (TLR2). Using a murine model of sterile systemic inflammatory response syndrome (SIRS), we observed that NOX2-deficient mice had dramatically increased mortality compared to WT mice. While both genotypes developed SIRS, characterized by hypothermia, hypotension, and leukopenia, the WT mice recovered within 48 h whereas the NOX2-deficient mice did not. Moreover, NOX2 function limited the extent of pulmonary pathology as significant lung injury was noted in the NOX2-deficient mice compared to the WT mice. Plasma analysis revealed that several inflammatory cytokines were persistently elevated in the NOX2-deficient mice, likely contributing to the ongoing inflammatory response. One of the complications seen in human SIRS patients is the development of multiple organ dysfunction syndrome (MODS). Thus, we next investigated the role of NOX2 in the progression from SIRS to MODS. Cellular analysis revealed continued neutrophil recruitment to the peritoneum and lungs of the NOX2-deficient mice and altered activation states of both neutrophils and macrophages. Histology showed multiple organ pathology indicative of MODS in the NOX2-deficient mice, and several inflammatory cytokines were elevated in lungs of the NOX2-deficient mice. Overall, these data suggest that NOX2 function protects against the development of MODS and is required for normal resolution of systemic inflammation. As we utilized a TLR2/6 agonist (zymosan) to induce SIRS in our in vivo model, we wanted to investigate neutrophil priming through TLR2 in an in vitro model. Notably, we determined that a TLR2/6 agonist, FSL-1, primed neutrophils from all donors to a similar extent, evidenced by direct and primed ROS generation, MAPK signaling, limited degranulation, and cytokine secretion. Surprisingly, Pam3CSK4, a TLR2/1 agonist, primed neutrophils from a subset of donors to a much greater extent than neutrophils from other donors. We demonstrated that the different neutrophil priming responses were the consequence of a common TLR1 polymorphism. In sum, the data presented here significantly advance our understanding of the roles of NOX2 and TLR2 signaling in host inflammation and neutrophil priming. This research could advance the development of therapies that target pathogenic neutrophil subsets in inflammatory conditions without compromising innate immune function
|
24 |
Enzymes impliqués dans la production des formes réactives de l'oxygène dans les membranes plasmiques, les mitochrondries et les chloroplastesHeyno, Eiri 09 December 2009 (has links) (PDF)
Les formes réactives de l'oxygène (FRO) ont été analysées dans différents compartiments cellulaires en utilisant des méthodes spectroscopiques (UV/VIS, fluorescence, infrarouge, résonance paramagnétique électronique). L'identité et les mécanismes catalytiques des enzymes qui produisent les FRO dans les membranes plasmiques (MP) et les mitochondries ont été étudiés, ainsi que le rôle protectif de l'oxydase terminale plastidiale (PTOX) des chloroplastes. Cd2+ s'est révélé être un inhibiteur de la NADPH oxydase des MP. In vivo Cd2+ inhibait la production extracellulaire de O2•- mais stimulait l'accumulation de H2O2. Dans des mitochondries isolées, Cd2+ a augmenté la production de FRO. Antimycin A a entraîné une élévation du H2O2 extracellulaire, confirmant que la mitochondrie est le site principal de production de l'H2O2 extracellulaire induite par Cd2+ in vivo. Une quinone réductase (QR) génératrice de FRO a été isolée des MP. La déprotonation pH-dépendante du quinole a produit des formes intermédiaires instables qui génèrent des FRO par réaction avec O2. Des espèces quinoniques ont été détectées dans la MP et pourraient servir de substrat aux QR in vivo. La protection de la chaine photosynthétique de transfert d'électron par la plastoquinol:O2 oxydoréductase a été étudiée chez des plantes PTOX+ surexprimant PTOX. En raison de leur réponse altérée en conditions de faible et forte intensité lumineuse, il a été proposé que pour fonctionner comme enzyme protectrice, PTOX est couplée à une SOD. Chez les lignées PTOX+, le niveau de SOD chloroplastique n'était pas plus élevé, limitant probablement leur capacité à détoxifier les taux élevés de O2•- généré.
|
25 |
Astrocyte-Mediated Oligodendrocyte Death Following Spinal Cord Injury: Glutamate, Zinc, and Oligodendrocyte-NADPH Oxidase Dependent MechanismsJohnstone, Joshua T. 12 October 2011 (has links)
Spinal cord injury (SCI) often results in irreversible paralysis and widespread oligodendrocyte death and white matter damage. While the mechanisms underlying this phenomenon are poorly understood, previous studies from our laboratory indicate that inhibition of astroglial-NF-κB activation reduces white matter damage and improves functional recovery in a mouse model of SCI. Here we provide novel evidence demonstrating that astrocytes directly regulate oligodendrocyte fate after trauma by a glutamate-mediated AMPA receptor dependent mechanism. Following trauma, elevated expression of the SLC39a10 zinc transporter correlated with an increase in zinc uptake by astrocytes, thereby reducing extracellular zinc concentrations required for AMPA receptor inhibition. Stimulation of AMPA receptors on oligodendrocytes by glutamate induced oligodendrocyte toxicity through the activation of the NADPH oxidase enzyme within oligodendrocytes. Genetic and pharmacological inhibition of active NADPH oxidase was sufficient to attenuate oligodendrocyte death in vitro. Following SCI, NADPH oxidase inhibition reduced oligodendrocyte death by ~75%, suggesting that glutamate-mediated oligodendrocyte death is dependent on the activation of the NADPH oxidase enzyme within oligodendrocytes. Combined treatment of the NADPH oxidase inhibitor apocynin and the AMPA receptor inhibitor NBQX significantly improved hind limb locomotor behavior, reduced white matter damage and lesion volume, and significantly spared descending serotonergic fibers. These studies provide a novel mechanism of oligodendrocyte death and may lead to clinically relevant therapeutics after SCI.
|
26 |
Reduced glutathione and NADPH oxidase inhibitor DPI alleviates ethephon-mediated leaf senescence, H2O2 elevation and senescence-associated gene expression in sweet potatoHuang, Chin-shu 23 November 2011 (has links)
Ethylene has long been considered as the main plant growth regulator that plays a key role in the regulation of leaf senescence. In sweet potato, ethephon, an ethylene releasing compound, promoted leaf senescence and H2O2 elevation. These ethephon-mediated effects were alleviated or attenuated by exogenous reduced glutathione and ascorbic acid. Ethephon treatment gradually increased endogenous total and reduced glutathione and ascorbic acid levels in sweet potato detached leaves 3 days after treatment. The H2O2 amount, however, was also increased at 72 h after treatment. Sweet potato detached leaves pretreated with reduced glutathione did significantly increased endogenous total and reduced glutathione levels at 24 h and remarkably decreased H2O2 amount at 72 h after ethephon application compared to that of ethephon alone control. Ethephon caused quick elevation of a small H2O2 peak at about 4 h after application, and the enhancement was eliminated by reduced glutathione pretreatment in treated sweet potato leaves. Pretreatment of diphenylene iodonium (DPI), an NADPH oxidase inhibitor, also repressed leaf senescence and H2O2 elevation at day 3 after ethephon treatment in sweet potato detached leaves, and the attenuation was effective within the first 4 h after ethephon treatment. For senescence-associated gene expression, ethephon and L-buthionine sulfoximine (BSO), an endogenous glutathione synthase inhibitor, did induced asparaginyl endopeptidase (SPAE) and cysteine proteases (SPCP1, SPCP2 and SPCP3) gene expression and the activation was repressed by reduced glutathione pretreatment. Based on these data we conclude that ethephon treatment may cause quick elevation of a small H2O2 peak likely via the NADPH oxidase, which may function as a signal component leading to leaf senescence, H2O2 elevation and senescence-associated gene expression in sweet potato detached leaves. The rate of endogenous antioxidant such as reduced glutathione elevation is also important and affects leaf senescence, H2O2 elevation and senescence-associated gene expression in sweet potato leaves.
|
27 |
Modulation of the immune response following myocardial infarction utilizing biomaterial-based therapeutic delivery strategiesSomasuntharam, Inthirai 21 September 2015 (has links)
In 2015, American Heart Association (AHA) reported that 1 in 9 deaths are attributed to Heart failure (HF), the number one killer in the world. While advancements in interventional cardiology in conjunction with pharmacotherapies have significantly reduced the rate of mortality following MI, there has been a corresponding rise in chronic heart failure (CHF) in surviving patients, largely attributed to the limited regenerative capacity of the heart and the inadequate healing response. Myocardial ischemic injury triggers an exuberant local and systemic inflammation, and the extent and quality of the cardiac wound healing process is intricately tied to the delicate equilibrium of this inflammatory response. While cardiac regeneration is an important goal, it is imperative in the meantime to explore therapeutic strategies that target these inflammatory mediators of early cardiac repair. These interventions to influence and improve cardiac wound healing can represent a new therapeutic window to halt the progression of heart failure between the few hours that may be used to limit infarct size by reperfusion and an irreversible non-contractile cardiac scar. This dissertation examines three therapeutic delivery strategies aimed at modulating the immune response to enhance cardiac repair in rodent models MI: 1) Polyketal nanoparticles as siRNA delivery vehicles for antioxidant therapy; 2) Spherical nucleic acid particles for anti-inflammatory therapy and; 3) Bioactive PEG (polyethyleneglycol)-based hydrogel for immunomodulation. The work presented here applies novel nucleic acid delivery strategies for cardiac gene silencing and has contributed to new knowledge with regard to modulating the immune response following MI.
|
28 |
Role of Intracellular Oxidant Release in Oxidised Low Lipoprotein - Induced U937 Cell DeathChen, Alpha Yan January 2012 (has links)
Atherosclerosis is a complex inflammation condition involving the accumulation of lipid-filled macrophages within the artery wall. Progression of the initial fatty streak to an advanced atherosclerotic plaque is characterized by the development of a necrotic core region containing cholesterol and dead cells. The oxidation of low-density lipoprotein (LDL) to oxidized LDL (oxLDL) and its subsequent uptake by macrophages to form foam cells are the key process in plaque formation. OxLDL is found within atherosclerotic plaque, and it is cytotoxic to a range of cells including macrophages through the generation of reactive oxygen species (ROS) and induction of oxidative stress.
The aim of this study was to examine the cytotoxic effects of oxLDL to U937 human monocyte-like cells. OxLDL caused a rapid concentration-dependent cell viability loss in U937 cells within 6 hours. The progression of oxLDL-induced cell death was found to be strongly correlated with the intracellular ROS production and intracellular glutathione (GSH) loss. OxLDL also caused a rapid loss of intracellular aconitase activity, indicating the impairment of the cellular metabolic function. The cytosolic calcium ion (Ca²⁺) level was also elevated by oxLDL, which could be from both intra- and extra-cellular sources.
OxLDL also activated plasma membrane superoxide generation complex NADPH oxidase (NOX), and the progression of oxLDL-induced NOX activation was correlated with oxLDL-mediated ROS production, suggesting NOX is the major source of ROS. Further investigations using NOX inhibitors apocynin or diphenyleneiodonium (DPI) found that inhibition of NOX prevented oxLDL-induced cell viability loss, ROS production, GSH loss and aconitase activity decrease. The cytosolic Ca²⁺ elevation caused by oxLDL was also suppressed slightly by inhibiting NOX activity. These results clearly show that NOX is the major site of oxidative stress upon oxLDL activation, contributing to the oxLDL-induced cell death.
This study also examined the protective effect of 7,8-dihydroneopterin (7,8-NP) on oxLDL-induced oxidative stress. 7,8-NP dramatically protected cells from oxLDL-induced cell viability loss, ROS generation and aconitase activity loss. 7,8-NP also inhibited oxLDL-induced cytosolic Ca²⁺ influx particularly after 3 hours. 7,8-NP did not inhibited mitochondrial aconitase activity decrease caused by oxLDL, nor inhibited mitochondrial ROS production. This indicates the protective effect of 7,8-NP against oxLDL damage could primarily in cytoplasm. The failure of 7,8-NP protection from oxLDL activating NOX suggests that the protection of 7,8-NP against oxLDL-induced oxidative stress was not due to the inhibition of NOX activation, but by radical scavenging activity of the NOX products.
|
29 |
Identification and quantification of regional expression of members of the NADPH oxidase (NOX) enzyme family during the estrous cycles in the bovine oviduct /Okasha, Mohamed Elsir Elnabeeb. January 2009 (has links)
Zugl.: Berlin, Freie University, Diss., 2009.
|
30 |
Insuficiência renal crônica, restrição de sono e sildenafil: consequências renais, cardíacas e sexuais em um modelo animal / Chronic kidney disease, sleep restriction and sildenafil: renal, cardiovascular and sexual consequencias in an animal modelHirotsu, Camila [UNIFESP] January 2013 (has links) (PDF)
Made available in DSpace on 2015-12-06T23:46:21Z (GMT). No. of bitstreams: 0
Previous issue date: 2013 / Associação Fundo de Incentivo à Psicofarmacologia (AFIP) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A insufiCiência renal cronica (IRC) e uma doenca de elevada morbidade e mortalidade, que requer tratamento de alto custo e possui grande impacto na qualidade de vida. Ao longo de sua progressao, e frequente o aparecimento dos disturbios de sono, os quais tem sido associados a uma menor chance de sobrevida nessa populacao. Devido a exposicao a situacoes estressoras como a dialise, a permanencia constante em ambiente hospitalar e a alta prevalencia de disturbios de sono, a restricao de sono constitui outro fator inerente ao cotidiano do paciente com IRC. Sabe-se, porem, que o sono exerce funcoes essenciais na restauracao e manutencao da homeostasia corporal, sugerindo um possivel papel da falta de sono no avanco da IRC. Assim, um tratamento alternativo que pudesse prevenir ou tratar as possiveis complicacoes decorrentes da falta de sono, melhorando a evolucao da doenca seria um avanco de grande relevancia. Nesse sentido, ressalta-se o uso do sildenafil, o qual tem apresentado efeitos beneficos no sistema renal, cardiovascular e sexual. Portanto, o presente estudo teve como objetivo investigar o papel do sono e do sildenafil na progressao da IRC por meio de duas investigacoes: 1) Estudo do padrao de sono na evolucao da IRC; 2) Avaliacao dos efeitos do sildenafil e da restricao de sono na progressao da IRC. Em relacao ao primeiro estudo, os resultados revelaram que animais com IRC apos oito semanas apresentaram um sono fragmentado e com inversao do ciclo vigilia-sono, que compensou sua necessidade homeostatica. No entanto, com 12 semanas de IRC, observou-se reducao do tempo total de sono e do sono paradoxal, alem do elevado numero de despertares. Em geral, a perda da funcao renal e o aumento da pressao arterial sistolica foram considerados fatores preditores independentes da piora na qualidade do sono. Em relacao ao segundo estudo, observou-se que o tratamento com sildenafil foi capaz de reduzir a proteinuria e as alteracoes da morfologia renal, aumentando o clearance de creatinina e evitando o desenvolvimento da hipertensao, a perda excessiva de peso, o hipogonadismo, a disfuncao eretil, a dislipidemia e o aumento de citocinas pro-inflamatorias. Entretanto, frente a restricao de sono esses efeitos beneficos foram atenuados, com excecao da melhora no desempenho sexual. Houve tambem um aumento da sobrevida induzido pelo tratamento com sildenafil, o qual em 75% o risco de mortalidade. No coracao, a expressao genica de eNOS e ECA2 aumentaram seletivamente nos animais IRC nao-restritos de sono, explicando em parte a reducao da hipertensao nesse grupo. Porem, um aumento da expressao cardiaca de NOX2 associado a elevados niveis de aldosterona foi encontrado no grupo IRC tratado com sildenafil e restrito de sono, o qual tambem apresentou aumento significativo da frequencia cardiaca. No rim, observou-se aumento na expressao de NOX2 e reducao de NOX4 e DDAH1 nos animais IRC comparados aos controles, independente do tratamento e da restricao de sono. A expressao de eNOS, no entanto, foi maior no grupo IRC tratado com sildenafil e naorestrito de sono. No testiculo, a restricao de sono elevou a expressao de eNOS, explicando em parte a melhora no comportamento sexual. Alem disso, uma reducao na expressao genica de DDAH1 e ECA2 foi identificada apenas no grupo IRC tratado com veiculo em comparacao aos demais grupos. No corpo cavernoso, a expressao de NOX2 foi reduzida pelo tratamento com sildenafil nos animais IRC, independente da restricao de sono, enquanto o aumento na expressao de eNOS e ECA2 foi observado apenas no grupo IRC tratado com sildenafil e nao-restrito de sono. Apos a restricao de sono, um aumento da expressao de iNOS foi observado apenas no grupo IRC tratado com veiculo. Em conclusao, o presente estudo mostrou que tanto as alteracoes na arquitetura do sono como a reducao no tempo de sono estao relacionadas a um maior avanco da IRC de maneira bidirecional. Alem disso, o tratamento com sildenafil apresentou beneficios na IRC, principalmente quando nao associado a restricao de sono, pois retarda o avanco da doenca e evita o desenvolvimento da hipertensao e da disfuncao eretil por meio de alteracoes mediadas em parte pela reducao da expressao de NOX2 e aumento de NOS, DDAH1 e ECA2 em multiplos orgaos. Apesar disso, um possivel efeito cardiotoxico deve ser mais bem investigado. Em suma, este trabalho sugere que para um melhor tratamento e evolucao da IRC se faz necessaria uma boa qualidade e quantidade adequada de sono / Chronic kidney disease (CKD) is a disease with high morbidity and mortality, which
requires costly treatment and has significant impact on quality of life. Along its
progression, it is usual the development of sleep disorders, which have been recenlty
linked to a lower chance of survival in this population. Due to the constant exposure
to stressful situations such as dialysis, kidney transplantation and stay at hospital
enviroment, sleep restriction is another factor inherent in the daily life of patients with
CKD. It is known, however, that sleep is essential for the restoration and
maintenance of body homeostasis, suggesting a possible role for lack of sleep to the
aggravation of CKD. Accordingly, an alternative treatment that could prevent or treat
possible complications arising from sleep debt and improve the disease outcomes
would be a breakthrough of great importance. Therefore, this study aimed to
investigate the role of sleep and sildenafil in the progression of CKD by two
investigations: 1) The study of sleep pattern in the evolution of CKD; 2) Effects of
sildenafil and sleep restriction in the progression of CKD. Regarding the first study,
the results revealed that after eight weeks, animals with CKD showed a fragmented
sleep in addition to a reversal pattern of sleep-wake cycle, which offset the sleep
homeostatic need. After 12 weeks of CKD, however, there was a reduction in the
total sleep time, mainly due to decrease of the paradoxal sleep, and an increase in
the number of awakenings. The loss of renal function and increase in systolic blood
pressure were considered independent predictors of the poor quality of sleep.
Regarding the second study, it was observed that the treatment with sildenafil was
able to reduce proteinuria and changes in renal morphology, increasing creatinine
clearance and preventing the development of hypertension, excessive weight loss,
hypogonadism, erectile dysfunction, dyslipidemia and the increase of proinflammatory
cytokines IL-1α, TNF α, and IL-17. However, given the sleep restriction
these effects were attenuated, with exception of the improvement in the sexual
behavior. There was also an increase in survival rate induced by treatment with
sildenafil, which decreased by 75% the risk of mortality. In the heart, the gene
expression of eNOS and ACE2 increased selectively in CKD non-restricted animals,
explaining in part the reduction of hypertension in this group. However, increased
cardiac expression of NOX2 associated with high aldosterone levels were found in
the CKD group treated with sildenafil and sleep restricted, which also showed a
significant increase in heart rate. In the kidney, we observed increased expression of
NOX2 and reduced NOX4 and DDAH1 in the CKD animals compared to controls,
regardless of treatment and sleep restriction. However, the expression of eNOS was
higher in the CKD group treated with sildenafil but non-sleep restricted compared to
CKD animals treated with vehicle and non-sleep restricted as well as with CKD
animals treated with sildenafil and sleep restricted. In the testis, sleep restriction
increased the expression of eNOS, explaining in part the improvement of sexual
performance. Furthermore, a reduction in the gene expression of ACE2 and DDAH1
were found only in the CKD animals treated with vehicle in relation to the other
groups. In the corpus cavernosum, the NOX2 expression was reduced by treatment
with sildenafil in the CKD animals, regardless of the sleep restriction. Also, increased
expression of eNOS and ACE2 were observed only in the CKD treated with sildenafil
and non-sleep restricted. After the sleep restriction, an increase of iNOS expression
was observed in the CKD group treated with vehicle. In conclusion, this study
showed that both the changes in sleep architecture and the reduction in sleep time
are related to further advancement of CKD in a bidirectional manner. In addition,
sildenafil has benefits in CKD, because it slows disease progression and prevents
the development of hypertension and erectile dysfunction through changes mediated
by the reduction of NOX2 and increase of NOS, ACE2 and DDAH1 gene expression
in multiple organs. Nevertheless, a possible cardiotoxic effect must be further
investigated. In general, this work suggests that for a better evolution of CKD it is
important an adequate quality and quantity of sleep. / BV UNIFESP: Teses e dissertações
|
Page generated in 0.0376 seconds