Thesis (Ph. D.)--Oklahoma State University, 2005. / Vita. Includes bibliographical references (p.103-107).

A Research report submitted to the Faculty of Health Sciences, Department of Internal Medicine, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the Degree of Master of Medicine in the Division of Cardiology. 2017 / INTRODUCTION The field of medicine has been challenged by the dual epidemic of heart failure and renal insufficiency. There is an increasing need to identify these patients at an early stage so as to delay progression to renal damage. Furthermore there is a lack of local data assessing the relationship between heart failure and renal dysfunction. AIMS • To identify the prevalence of renal dysfunction in patients attending the heart failure clinic at Charlotte Maxeke Johannesburg Academic hospital (Cardiorenal syndrome Type II) • To evaluate the relationship between severity of heart failure and severity of renal dysfunction • To compare heart failure with reduced ejection fraction (HFREF) variables between patients with and without renal dysfunction. METHODOLOGY This study is a single center retrospective study of patients attending Charlotte Maxeke Johannesburg Academic Hospital Heart Failure Clinic. Heart failure patients included in this study were those with an ejection fraction < 50% as this is an accepted definition for HFREF. Patients with HFREF were analyzed specifically for the following; presence of renal dysfunction, Ejection Fraction (EF), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Haemoglobin (HB), New York Heart Association (NYHA) functional class, furosemide dose , six minute walk test (6MWT) and Minnesota Living with Heart Failure Questionnaire (MLFQ) score . Presence of renal dysfunction was identified based on the glomerular filtration rate (eGFR) value of less than 60ml/min/1.73m2 as this is the threshold eGFR below which complications of renal impairment appear. The eGFR was calculated using the Modification of Diet in Renal Disease (MDRD) abbreviated formula: (186.3 X serum creatinine) -1.154 x (age) -0.203 x (0.742 if female) x (1.212 if African) The control group consisted of patients attending the clinic who did not have renal dysfunction. RESULTS A total 242 files were reviewed. Forty-two files were excluded from the study due to lack of adequate study data recorded in the file. Data was collected and entered into a database, which was analyzed using the Statistics/Data Analysis Program (STATA) Version 10.0. The mean age of the study group was 53.3 years (SD± 15.05) with the youngest subject being 21 years old and the oldest subject aged 85 years. The mean SBP was 119mmHg and the mean DBP was 75mmHg. The mean eGFR was 72.01 ml/min/1.73m2. The overall prevalence of low eGFR (<60ml/min/1.73m2) in the sample population was 34.5 %. The prevalence in female and male patients with a low eGFR was 35% and 33.6% respectively. Analysis of MLFQ, 6MWT, DBP and age yielded a positive correlation with eGFR, which was statically significant (p<0.05). An insignificant correlation was obtained comparing eGFR with SBP (p=0.07), EF (p=0.69) and HB (p=0.79). The Analysis of Variance Test (ANOVA), showed a significant correlation between eGFR values across the different NYHA functional classes (p 0.012). Thus it was found that the higher the NYHA class (clinically worse) was associated with worse renal function. The mean eGFR for NYHA I was 77.05 ml/min/1.73m2, for NYHA II was 70.61 ml/min/1.73m2, for NYHA III was 64.13 ml/min/1.73m2 and NYHA IV was 50.02 ml/min/1.73m2. DISCUSSION The overall prevalence of low eGFR (<60ml/min/1.73m2) in this study was 34.5%, a finding consistent with international trials. The majority of patients in this study were in NYHA functional class I or II, thereby highlighting the fact that renal dysfunction is common in heart failure patients and starts early. Statistically significant values were also obtained between eGFR and 6MWT, MLFQ, furosemide dose, age and DBP. The patients with higher 6MWT have better effort tolerance, thereby classifying their heart failure as milder. This in effect confirms that higher eGFR patients have higher effort tolerance. Higher MLFQ scores and higher furosemide doses are inversely correlated to eGFR. The more subjective symptoms you have, and the higher doses of furosemide you need, is a reflection of the severity of the heart failure. With regards to age, there is a normal physiological decline in eGFR with increasing age. In this study a statistically significant negative correlation between eGFR and NYHA was found. Thus a higher NYHA class is associated with worse renal function. This suggests that the clinically more advanced the patient, the poorer the renal function. Also, the prevalence of low eGFR (<60ml/min/1.73m2) within each NYHA class, as expected, increased with increasing NYHA class. It was 27% for NYHA I, 38% for NYHA II, 40% for III, while class IV had 80% of low eGFR prevalence CONCLUSION The findings of this study confirm that the cardio-renal syndrome is common in a local cohort of heart failure patients. The study also suggests that renal dysfunction starts in the early stages of heart failure (NYHA I/II) and becomes more prevalent in patients with more advanced stages of heart failure. These findings highlight the need to treat heart failure patients early after presentation and more appropriately if we are to decrease complications such as renal dysfunction, thereby improving morbidity and mortality. / MT2018

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / The increase in accidents involving Africanized bees in Brazil and throughout Latin America in recent decades has become the object of surveillance by the health authorities, because of accidents with hundreds of bees to be associated with frames of poisoning. The venom of the honeybee Apis mellifera is a mixture of toxic peptides with various local and systemic actions. The objective of this study was to evaluate the renal and vascular changes promoted by the whole venom of the bee A. mellifera and its fractions PLA2 and melittin. Male Wistar rats (250-300g) whose kidneys were isolated and perfused with Krebs-Henseleit solution containing modified 6g% bovine albumin previously dialyzed. The evaluation of the vascular effects of the venom of Apis mellifera in pots was carried out using conductance tests ring of isolated rat aorta. The results showed that the whole venom of A. mellifera and the complexed fraction (PLA2+melittin) promoted significant changes in all renal parameters studied, producing an increase in renal perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (FU) and the glomerular filtration rate (GFR), all these changes were seen at concentrations of 3&#956;g/mL and 10&#956;g/mL. However, the lower concentration (1&#956;g/mL) had no effect on the evaluated parameters. It was observed a significant reduction in the percentage of tubular transport of sodium (Na+), potassium (K+) and chloride (Cl-), suggesting that the whole venom and the fraction complexed (PLA2+melittin) engaged on the renal tubular injury. Were also observed in protein deposition in the renal tubules histological focal regions with necrosis/apoptosis, and was found reduced the viability of the MDCK cells and an increased of the enzyme lactate dehydrogenase (LDH), whose concentration dependent cytotoxic effect with a value IC50 47.84&#956;g/mL. In this sense, the results suggest that the renal lesions were necrosis in the tested conditions. It had been shown in the protocol of aortic ring an increase in contractility. In conclusion, the whole venom and the fraction complexed (PLA2+melittin) of bee Apis mellifera caused nephrotoxicity, suggesting a direct action on cell death in renal tubule cells by necrosis. The contractile effect of bee venom involves the opening of calcium channels operated by voltage and suggest a role of alpha adrenergic receptors via activation of phospholipase C. This finding confirms the results found in the isolated rat kidney and there was an increase in pressure due to renal perfussÃo possible vasoconstriction of the vessels supplying the kidney. Studies of the venom and its fractions in different systems provide a greater understanding of the pathophysiology and an elucidation of the mechanisms observed. Thus, it can lead to the discovery of pharmacological tools and bioprospecting in the components present in the venom. / O aumento dos acidentes envolvendo abelhas africanizadas no Brasil e em toda a AmÃrica, nas Ãltimas dÃcadas, passou a ser objeto de vigilÃncia das autoridades sanitÃrias, devido ao fato dos acidentes com centenas de abelhas estarem associadas a quadros de envenenamento. O veneno da abelha Apis mellifera à uma mistura de peptÃdeos tÃxicos com diversas aÃÃes locais e sistÃmicas. O objetivo do presente trabalho foi avaliar as alteraÃÃes renais e vasculares promovidas pelo veneno total da abelha A. mellifera e de suas fraÃÃes PLA2 e melitina. Foram utilizados ratos Wistar machos (250-300g), cujos rins foram isolados e perfundidos com soluÃÃo de Krebs-Henseleit modificado contendo 6g% de albumina bovina previamente dialisada. A avaliaÃÃo dos efeitos vasculares do veneno de Apis mellifera em vasos de condutÃncia foi realizada atravÃs dos ensaios em anel de aorta isolado de rato. Os resultados encontrados demonstraram que o veneno total de A. mellifera e da fraÃÃo complexada (PLA2 + melitina) promoveram alteraÃÃes significativas em todos os parÃmetros renais estudados, produzindo um aumento na pressÃo de perfusÃo renal (PP), na resistÃncia vascular renal (RVR), no fluxo urinÃrio (FU) e no ritmo de filtraÃÃo glomerular (RFG), todas essas alteraÃÃes foram verificadas nas concentraÃÃes de 3Âg/mL e 10Âg/mL. PorÃm, a menor concentraÃÃo (1Âg/mL) nÃo apresentou efeito nos parÃmetros avaliados. Foi verificada uma reduÃÃo significativa no percentual de transporte tubular de sÃdio (Na+), potÃssio (K+) e cloreto (Cl-), sugerindo que o veneno total e a fraÃÃo complexada (PLA2 + melitina) exerÃam injÃria sobre os tÃbulos renais. TambÃm foram observadas depÃsito de proteÃnas nos tÃbulos renais nas anÃlises histolÃgicas com regiÃes focais de necrose/apoptose, bem como foi constatada reduÃÃo da viabilidade das cÃlulas MDCK e do aumento da enzima lactato desidrogenase (LDH), cujo efeito citotÃxico dependente de concentraÃÃo com um valor de IC50 47.84Âg/mL. Nesse sentido, os resultados sugerem que as lesÃes renais foram por necrose nas condiÃÃes testadas. Foi demonstrado no protocolo de anel de aorta um aumento na contratilidade. Em conclusÃo, o veneno total e a fraÃÃo complexada (PLA2 + melitina) da abelha Apis mellifera causaram nefrotoxicidade, sugestivo de uma aÃÃo direta com morte celular em cÃlulas do tÃbulo renal por necrose. O efeito contrÃtil do veneno de abelha envolve a abertura de canais de cÃlcio operados por voltagem e sugerem a participaÃÃo dos receptores alfa adrenÃrgicos via ativaÃÃo da enzima fosfolipase C. Esse achado corrobora com os resultados encontrados em rim isolado de rato, verificando-se um aumento da pressÃo de perfusÃo renal devido a uma possÃvel vasoconstricÃÃo dos vasos que irrigam o rim. Os estudos do veneno e suas fraÃÃes em diferentes sistemas propiciam um maior conhecimento da fisiopatologia e uma elucidaÃÃo dos mecanismos observados. Desta forma, pode levar à descoberta e bioprospecÃÃo de ferramentas farmacolÃgicas em componentes presentes no veneno.

Il existe des interactions profondes entre les fonctions rénales et cardiaques. Un dysfonctionnement de l'un ou l'autre de ces deux organes entraîne un dysfonctionnement du second. Ces interactions entre coeur et rein sont regroupées sous le terme de syndromes cardio-rénaux. Les biomarqueurs sont, par définition des indicateurs objectivement mesurés d'un processus biologique normal, d'un processus pathologique ou d'une réponse pharmacologique à une intervention thérapeutique. Les marqueurs biologiques dont très utiles à l'exploration des phénomènes pathologiques cardiaques et rénaux. En pratique clinique, la fonction rénale est quotidiennement estimée à partir de biomarqueurs de filtration glomérulaire, la créatinine et la cystatine C en premier lieu. Dans l'exploration des fonctions cardiaques, des évolutions importantes ont eu lieu ces dernières années. Au niveau analytique, des améliorations significatives des performances ont abouti à la mise sur le marché de méthodes dites hypersensibles de mesure de la troponine. De plus de nouveaux marqueurs explorant de nouveaux aspects physiopathologiques de la dysfonction cardiaque sont également intensément étudiés, tels que les marqueurs de fibrose (ST2 soluble, galectine-3). Après une revue de la bibliographie des biomarqueurs rénaux et cardiaques, ce travail s'attache à l'étude de l'optimisation de l'usage des biomarqueurs rénaux et cardiaques, tout d'abord par la maîtrise des procédés analytiques puis dans l'utilisation de ceux-ci en pratique clinique.Dans une première partie consacrée aux marqueurs rénaux, nous cherchons à optimiser l'utilisation des marqueurs permettant d'estimer au mieux le débit de filtration glomérulaire, meilleur index connu de la fonction rénale. En pratique clinique, le débit de filtration glomérulaire est estimé à partir de la créatinine. Au niveau analytique, nous montrons dans ce travail que les méthodes colorimétriques, basées sur la réaction de Jaffé, devraient désormais être abandonnées au profit des méthode enzymatiques. Ces résultats sont illustrés dans différentes populations de patients, une cohortes issue des bases de données hoispitalières ainsi qu'une population de patients cirrhotiques. Chez ces derniers,la créatinine présente d'importantes limites en tant que marqueur de filtration glomérulaire, en particulier en raison d'une diminution de la masse musculaire. La cystatine C représente dans ce contexte une alternative intéressante puisque ce marqueur n'est pas dépendant de la masse musculaire. Des algorithmes utilisant la cystatine C, seule ou en association avec la créatinine ont récemment été proposés dans la litérrature.Dans une seconde partie, nous nous interressons aux marqueurs cardiaques. Les troponines cardiaques sont des protéines présentes au niveau de l'appareil contractile du cardiomyocyte, relarguées dans la circulation en cas de nécrose cellulaire. L'arrivée récente de méthodes capables de mesurer des concentrations circulantes dans une part importante de la population saine a obligé d'une part à un contrôle strict des procédés analytiques par les fabricant et d'autre part à une adaptation des cliniciens afin de tirer partie des nouvelles informations apportées par ces marqueurs dans différentes populations présentant des élévations chroniques (sujets âgés, insuffisants rénaux chroniques) ou aiguës (cinétiques post infarctus du myocarde). Enfin, une étude concernant le ST2 soluble, marqueur émergent de fibrose dans l'insuffisance cardiaque est également présentée.En conclusion, l'optimisation de l'usage des biomarqueurs s'oriente à l'heure actuelle vers des stratégies multimarqueurs, comme l'association créatinine et cystatine C dans l'estimation du débit de filtration glomérulaire ou le développement de scores pronostics associant troponine, peptides natriurétiques et ST2 soluble dans l'insuffisance cardiaque. / Profound interactions exist between cardiac and renal functions. Acute or chronic dysfunction of an organ may induce acute or chronic dysfunction of the other. These complex interactions have been grouped under the term cardiorenal syndrome.A Biomarker is defined as a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. Biological markers are useful for the exploration of pathological renal and cardiac phenomenon. In clinical practice, renal function is estimated from glomerular filtration markers, mainly creatinine and cystatin C. Much progress has recently been made recently toward exploration of cardiac dysfunction. From an analytical point of vue, improvement in measurement of cardiac troponine led to the so-called hypersensitive cardiac troponin assays. Furthermore, new markers of cardiac dysfunction are under initensive inverstigation. These markers(soluble ST2, galectin-3) provide information regarding specific pathophysiological pathways, such as fibrosis.After a review of the litterature regarding cardiac and renal biomarkers, this work aims at optimize the interpretation of abovementioned biological markers.In the fist part, consacred to renal markers, this work tries to optimize the estimation of glomerular filtration rate, firstly regarding analytical process then in clinical practice. Glomerular filtration rate is in clincal practice derived from creatinine level. Analytically, our work indaicates that compensated Jaffe methods for the measurement of creatinine should be replaced with enzymatic ones, which are muche more performant. These conclusions have been drawn in different populations, from hospital databases and in cirrhotic patients. In this population , creatinine as a filtration marker suffers from important limitations, mainly beacause of the loss of muscle mass observed in these patients. Cystatin C is an alternative filtration marker whose level is independent of muscle mass. Some algorithms predicting glomerular filtration rate from cystatin C, sole or in association with creatinine have recently been proposed.The second part of this work is consacred to cardiac markers. Cardiac troponins , proteins which are part of the contractile apparatus, are released in the blood flow in case of necrosis. The recent improvement of analytical methods, enabling measurement of cardiac troponine levels in at leats 50% of a healthy reference population require a precise control of manufacturing process. Furthermore, hypersensitive troponins require from physician an exact interpretation in patients with chronic (elderly, chronic kidney disease patients) or acute (post myocardial infarction kinetics) elevation. A study regarding soluble ST2, a n emerging marker of cardiac fibrosis, is also presentedOptimization of the use of biomarkers move nowadays toward multimarkers strategies as illustrated by approaches combining cystatin C with creatinine for estimating glomerular filtration rate or the development of scores for predicting mortality risk in heart failure patients based on cardiac troponins, natriuretic peptides and soluble ST2.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Sea anemones contain a variety of biological active compounds including some potent toxins. For this reason, many investigators have focused their studies in these proteins, isolated from sea anemones, such as Bunodosoma caissarum. The aim of this work was to study the mechanism of functional alterations produced by the crude extract and the PLA2 fraction of B. caissarum in the isolated rat kidney and arteriolar mesenteric bed. Isolated kidneys from Wistar rats, weighing 250-300g, were perfused with Krebs-Henseileit solution containing 6% of bovine serum albumin for 120 min. B. caissarum crude extract (BcE) and PLA2 were added to the system 30 min after the beginning of each experiment (internal control) and Tezosentan (TZN) and Indomethacin (IND) were administered in the initial period of each experiment (T=0min). The mesenteric bed, kept warmed at 37ÂC, was perfused with Krebs solution at a constant flow, (4mL/min) but with a variable perfusion pressure, measured for 80 min. mRNA expression of TNF-&#945;, IL-1&#946;, rennin and adenosine receptors (A1, A2a, A2b and A3) was evaluated by PCR using 18S mRNA as reference gene. The data were analyzed by Studentâs t-test (p<0.05). BcE altered kidney function increasing perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (UF), glomerular filtration rate (GFR) and sodium, potassium and chloride excretion, especially with the intermediary concentraÃÃo. Tezosentan inhibited these effects only partially. However, indomethacin presented a blockage more expressive that TZN. The PLA2 of B. caissarum showed a higher increase of PP at 60 minutes (Control= 104,17Â3,72; PLA2(0,1) = 130,9Â5,6*; PLA2(0,3) = 165,1Â12,6*; PLA2(1,0) = 142,3Â9,6*, *p<0,5) and increased RVR, UF, GFR, sodium, potassium and chloride excretion and urinary osmolarity, with descrease of Na+, K+ and Cl- distal transports.. The blockage of IND was more expressive on the smallest PLA2 concentraÃÃo and TZN showed a modest effect, blocking more efficiently the intermediary concentraÃÃo. Neither BcE, nor PLA2 altered the basal perfusion pressure of the isolated arteriolar mesenteric bed. PLA2 increased the gene expression of TNF-&#945; (Control = 1,00  0,00 vs. PLA2 = 1,116  0,033*, com p<0,0001)and upnregulated the expression of adenosine receptors A2a (Control = 1,0  0,01 vs. PLA2 = 1,238  0,043*, com p<0,0001). These results suggest that BcE and PLA2 exert significative actions in the isolated perfusion kidney, without vascular effects in the arteriolar mesenteric bed. COX-2 and endothelin appear to be important mediators of the effects of BcE and PLA2. In addition, adenosine is also involved in the mechanism of action of B. caissarum / AnÃmonas marinhas contÃm uma variedade de compostos biologicamente ativos incluindo potentes toxinas. Por esta razÃo, muitos investigadores tÃm centrado seus estudos nestas proteÃnas, isoladas de anÃmonas marinhas, como Bunodosoma caissarum. O objetivo deste trabalho foi estudar o mecanismo das alteraÃÃes funcionais produzidas pelo extrato bruto e da fraÃÃo PLA2 de B. caissarum em rim isolado de rato e leito vascular mesentÃrico. Rins isolados de ratos Wistar, pesando 250-300g, foram perfundidos durante 120 min com soluÃÃo de Krebs-Henseileit contendo 6% de albumina bovina. O extrato bruto de B. caissarum (BcE) e PLA2 foram adicionados ao sistema, em diferentes concentraÃÃes, 30 minutos apÃs o inÃcio de cada experimento (controle interno) e Tezosentan (TZN) e Indometacina (IND) foram administrados no perÃodo inicial de cada experimento (T = 0 min). O leito vascular mesentÃrico, mantido aquecido a 37  C, foi perfundido com soluÃÃo de Krebs em um fluxo constante (4mL/min) e a pressÃo medida por 80 min. A expressÃo de mRNA TNF-&#945;, IL-1 &#946;, renina e receptores de adenosina (A1, A2a, A2b e A3) foi avaliada por PCR utilizando como referÃncia o mRNA do gene 18S. Os dados foram analisados por teste t de Student (p <0,05). BcE alterou a funÃÃo renal elevando a pressÃo de perfusÃo (PP), a resistÃncia vascular renal (RVR), fluxo urinÃrio (UF), taxa de filtraÃÃo glomerular (TFG) e excreÃÃo de sÃdio, de potÃssio e cloreto, especialmente com a concentraÃÃo intermediÃria. Tezosentan inibiu estes efeitos apenas parcialmente. No entanto, indometacina apresentou um bloqueio mais expressivo que TZN. A PLA2 de B. caissarum elevou a pressÃo de perfusÃo (PP) jà aos 60 minutos (controle = 104,17  3,72; PLA2 (0,1) = 130,9  5,6 *; PLA2 (0,3) = 165,1  12,6 *; PLA2 (1,0) = 142,3  9,6 *, *p <0,5), revelando tambÃm elevaÃÃes de RVR , UF, TFG, excreÃÃo de eletrÃlitos e osmolaridade urinÃria, com diminuiÃÃo dos transportes distais de Na+, K+ e Cl-. O bloqueio com IND foi mais expressivo sobre a menor concentraÃÃo de PLA2, enquanto TZN mostrou um efeito discreto. BcE e PLA2 nÃo alteraram a pressÃo de perfusÃo basal do leito vascular mesentÃrico. PLA2 aumentou a expressÃo relativa de TNF&#945; (C = 1,00  0,00 vs. PLA2 = 1,116  0,033*, com p<0,0001) e do receptor de adenosina A2a (C = 1,0  0,01 vs. PLA2 = 1,238  0,043*, com p<0,0001).Estes resultados sugerem que BcE e PLA2 exercem aÃÃes significativas na perfusÃo de rim isolado, sem efeitos vasculares diretos no leito mesentÃrico. COX-2 e endotelina parecem ser importantes mediadores dos efeitos da BcE e PLA2. AlÃm disso, adenosina tambÃm parece estar envolvida no mecanismo de aÃÃo da PLA2 de Bunodosoma caissarum.

No description available.

SOUSA, Paulo Cesar Pereira de. Estudos das alterações renais e vasculares induzidos pelo veneno e frações isoladas de abelha Apis mellifera.2012. 176 f. : Tese (doutorado) - Universidade Federal do Ceará, Centro de Ciências, Faculdade de Medicina, Departamento de Fisiologia e Farmacologia, Programa de Pós-Graduação de Biotecnologia, Fortaleza-CE, 2012 / Submitted by demia Maia (demiamlm@gmail.com) on 2016-05-27T14:44:54Z No. of bitstreams: 1 2012_tese_pcpsousa.pdf: 7871361 bytes, checksum: c08e421b0e8f5a30a3d35df159ea6a7d (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-05-27T14:49:38Z (GMT) No. of bitstreams: 1 2012_tese_pcpsousa.pdf: 7871361 bytes, checksum: c08e421b0e8f5a30a3d35df159ea6a7d (MD5) / Made available in DSpace on 2016-05-27T14:49:38Z (GMT). No. of bitstreams: 1 2012_tese_pcpsousa.pdf: 7871361 bytes, checksum: c08e421b0e8f5a30a3d35df159ea6a7d (MD5) Previous issue date: 2012 / The increase in accidents involving Africanized bees in Brazil and throughout Latin America in recent decades has become the object of surveillance by the health authorities, because of accidents with hundreds of bees to be associated with frames of poisoning. The venom of the honeybee Apis mellifera is a mixture of toxic peptides with various local and systemic actions. The objective of this study was to evaluate the renal and vascular changes promoted by the whole venom of the bee A. mellifera and its fractions PLA2 and melittin. Male Wistar rats (250-300g) whose kidneys were isolated and perfused with Krebs-Henseleit solution containing modified 6g% bovine albumin previously dialyzed. The evaluation of the vascular effects of the venom of Apis mellifera in pots was carried out using conductance tests ring of isolated rat aorta. The results showed that the whole venom of A. mellifera and the complexed fraction (PLA2+melittin) promoted significant changes in all renal parameters studied, producing an increase in renal perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (FU) and the glomerular filtration rate (GFR), all these changes were seen at concentrations of 3μg/mL and 10μg/mL. However, the lower concentration (1μg/mL) had no effect on the evaluated parameters. It was observed a significant reduction in the percentage of tubular transport of sodium (Na+), potassium (K+) and chloride (Cl-), suggesting that the whole venom and the fraction complexed (PLA2+melittin) engaged on the renal tubular injury. Were also observed in protein deposition in the renal tubules histological focal regions with necrosis/apoptosis, and was found reduced the viability of the MDCK cells and an increased of the enzyme lactate dehydrogenase (LDH), whose concentration dependent cytotoxic effect with a value IC50 47.84μg/mL. In this sense, the results suggest that the renal lesions were necrosis in the tested conditions. It had been shown in the protocol of aortic ring an increase in contractility. In conclusion, the whole venom and the fraction complexed (PLA2+melittin) of bee Apis mellifera caused nephrotoxicity, suggesting a direct action on cell death in renal tubule cells by necrosis. The contractile effect of bee venom involves the opening of calcium channels operated by voltage and suggest a role of alpha adrenergic receptors via activation of phospholipase C. This finding confirms the results found in the isolated rat kidney and there was an increase in pressure due to renal perfussão possible vasoconstriction of the vessels supplying the kidney. Studies of the venom and its fractions in different systems provide a greater understanding of the pathophysiology and an elucidation of the mechanisms observed. Thus, it can lead to the discovery of pharmacological tools and bioprospecting in the components present in the venom. / O aumento dos acidentes envolvendo abelhas africanizadas no Brasil e em toda a América, nas últimas décadas, passou a ser objeto de vigilância das autoridades sanitárias, devido ao fato dos acidentes com centenas de abelhas estarem associadas a quadros de envenenamento. O veneno da abelha Apis mellifera é uma mistura de peptídeos tóxicos com diversas ações locais e sistêmicas. O objetivo do presente trabalho foi avaliar as alterações renais e vasculares promovidas pelo veneno total da abelha A. mellifera e de suas frações PLA2 e melitina. Foram utilizados ratos Wistar machos (250-300g), cujos rins foram isolados e perfundidos com solução de Krebs-Henseleit modificado contendo 6g% de albumina bovina previamente dialisada. A avaliação dos efeitos vasculares do veneno de Apis mellifera em vasos de condutância foi realizada através dos ensaios em anel de aorta isolado de rato. Os resultados encontrados demonstraram que o veneno total de A. mellifera e da fração complexada (PLA2 + melitina) promoveram alterações significativas em todos os parâmetros renais estudados, produzindo um aumento na pressão de perfusão renal (PP), na resistência vascular renal (RVR), no fluxo urinário (FU) e no ritmo de filtração glomerular (RFG), todas essas alterações foram verificadas nas concentrações de 3µg/mL e 10µg/mL. Porém, a menor concentração (1µg/mL) não apresentou efeito nos parâmetros avaliados. Foi verificada uma redução significativa no percentual de transporte tubular de sódio (Na+), potássio (K+) e cloreto (Cl-), sugerindo que o veneno total e a fração complexada (PLA2 + melitina) exerçam injúria sobre os túbulos renais. Também foram observadas depósito de proteínas nos túbulos renais nas análises histológicas com regiões focais de necrose/apoptose, bem como foi constatada redução da viabilidade das células MDCK e do aumento da enzima lactato desidrogenase (LDH), cujo efeito citotóxico dependente de concentração com um valor de IC50 47.84µg/mL. Nesse sentido, os resultados sugerem que as lesões renais foram por necrose nas condições testadas. Foi demonstrado no protocolo de anel de aorta um aumento na contratilidade. Em conclusão, o veneno total e a fração complexada (PLA2 + melitina) da abelha Apis mellifera causaram nefrotoxicidade, sugestivo de uma ação direta com morte celular em células do túbulo renal por necrose. O efeito contrátil do veneno de abelha envolve a abertura de canais de cálcio operados por voltagem e sugerem a participação dos receptores alfa adrenérgicos via ativação da enzima fosfolipase C. Esse achado corrobora com os resultados encontrados em rim isolado de rato, verificando-se um aumento da pressão de perfusão renal devido a uma possível vasoconstricção dos vasos que irrigam o rim. Os estudos do veneno e suas frações em diferentes sistemas propiciam um maior conhecimento da fisiopatologia e uma elucidação dos mecanismos observados. Desta forma, pode levar à descoberta e bioprospecção de ferramentas farmacológicas em componentes presentes no veneno.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A hipertensão arterial sistêmica (HAS) caracteriza-se pelo aumento crônico da resistência vascular periférica, determinado essencialmente na microcirculação, que resulta de alterações vasculares funcionais e estruturais. Além disso, a redução da densidade arteriolar e capilar (rarefação da microcirculação) contribui para a elevação da pressão arterial na HAS. Nesse contexto, sabe-se que a hiperatividade do sistema nervoso simpático central está envolvida na fisiopatologia das alterações tanto funcionais quanto estruturais da HAS. No presente trabalho, investigamos os efeitos do tratamento crônico (28 dias) com anti-hipertensivos de ação central sobre a rarefação capilar funcional e/ou estrutural na pele, músculo esquelético e miocárdio de ratos espontaneamente hipertensos (SHR) adultos, modelo clássico de hipertensão arterial primária. Os ratos Wistar Kyoto (WKY) foram utilizados como controles normotensos. Foram utilizadas doses equipotentes de clonidina (0,1 mg/kg/dia), rilmenidina (1 mg/kg/dia) e moxonidina (10 mg/kg/dia), com relação ao efeito anti-hipertensivo. Também foram estudados os efeitos dos tratamentos sobre a massa ventricular esquerda. Para avaliação da densidade capilar funcional utilizamos microscopia por epi-iluminação e fluorescência e para avaliação da densidade capilar estrutural técnicas de marcação histoquímica dos capilares. Os resultados mostraram que houve aumento do número de capilares espontaneamente perfundidos (densidade funcional) na pele e no músculo esquelético de SHR tratados com todos os fármacos, com relação ao grupo SHR não tratado. Além disso, foi observada reversão da rarefação capilar estrutural no músculo esquelético de SHR com todas as drogas utilizadas. Por outro lado, não houve reversão da rarefação capilar estrutural no ventrículo esquerdo em nenhum grupo experimental. Finalmente, a hipertrofia do ventrículo esquerdo foi parcialmente revertida em SHR tratados com rilmenidina. Em conclusão, nossos resultados demonstraram que, além da redução da pressão arterial, a utilização de agentes anti-hipertensivos de ação central resulta na reversão de alterações microcirculatórias de ratos espontaneamente hipertensos e o uso de rilmenidina favorece a regressão da hipertrofia cardíaca. Os resultados também sugerem que a inibição da hiperatividade simpática central induz efeitos benéficos na microcirculação na hipertensão arterial. / Essential hypertension (EH) is characterized by chronic increases in peripheral vascular resistance, mainly resulting from functional and structural alterations of the microcirculation. Moreover, a reduction of arteriolar and capillary density (microvascular rarefaction) is involved in the increase of arterial pressure in EH. In addition, central sympathetic overactivity is involved in the pathophysiology of functional and structural alterations of the cardiovascular system in EH. In the present work, we investigated the effects of a long-term treatment (28 days) with centrally-acting antihypertensive drugs on functional and/or structural capillary rarefaction in the skin, skeletal muscle and heart of adult spontaneously hypertensive rats (SHR), a classical experimental model of EH. We also investigated the effects of the treatments on left ventricular mass in SHR. Wistar Kyoto rats were used as normotensive controls. We used equipotent anihypertensive doses of clonidine (0.1 mg/kg/day), rilmenidine (1 mg/kg/day) and moxonidine (10 mg/kg/day). Functional capillary density was evaluated using epi-illuminated fluorescence video-microscopy while structural capillary density was studied using a histochemical tracer of capillaries. Our results showed that there was an increase in the number of spontaneously perfused capillaries (functional density) in the skin and skeletal muscle of SHR in all treatment groups, when compared to the non-treated SHR group. Moreover, there was a reversion of structural capillary rarefaction in the skeletal muscle with all drug treatments. On the other hand, there was no reversion of structural capillary rarefaction of the left ventricle in any experimental group. Finally, left ventricular hypertrophy was partially reversed in the group of SHR treated with rilmenidine. In conclusion, our results showed that besides arterial pressure reduction, long-term treatment with centrally-acting antihypertensive drugs induces a reversal of microcirculatory alterations in SHR and rilmenidine favors the regression of left ventricular hypertrophy. The results also suggest that the modulation of central sympathetic overactivity induces beneficial effects on the microcirculation in the hypertensive disease.

Pré-eclâmpsia (PE), uma síndrome sistêmica da gestação caracterizada por proteinúria e hipertensão, está associada a uma significativa mortalidade tanto materna quanto fetal. Eentretanto, sua fisiopatologia ainda não é totalmente compreendida. Apesar de um expressivo aumento da atividade do sistema renina-angiotensina (SRA) na gestação normal, a pressão arterial não aumenta. Além disso, a redução da pressão de perfusão intra-uterina promove um aumento na liberação de espécies reativas de oxigênio que podem contribuir para a hipertensão na gestação. Dessa forma, o objetivo deste trabalho foi estudar o papel do SRA vascular, assim como, do estresse oxidativo plasmático, cardiorenal e placentário para a regulação cardiovascular materna em ratas normotensas e em modelo de PE induzida por L-NAME. Foi observado um aumento da pessão arterial em animais que receberal L-NAME. As ratas grávidas + L-NAME apresentaram um menor ganho de massa corporal durante a gestação, menor múmero de filhotes vivos, maior número de abortos, menor massa placentária total e fetos com menor massa corporal. Foi observada uma redução na resposta vasodilatadora induzida por acetilcolina (ACh) e angiotensina (Ang) II, aumento na resposta vasodilatadora induzida por nitroglicerina (NG) e aumento na resposta vasoconstritora induzida por fenilefrina (Phe) e Ang II em LAM de ratas grávida e não grávidas que receberam L-NAME. Não foi observada diferença na expressão dos receptores AT1 e AT2 e das enzimas ECA, ECA2 e eNOS. Foi observado um aumento na concentração plasmática de renina e bradicinina (BK) em ratas grávidas + L-NAME e uma redução na concentração de Ang 1-7. As ratas grávidas e grávidas + L-NAME apresentaram um aumento nos níveis séricos de estradiol. Os níveis de malondialdeído e carbonilação de proteínas estava aumentados e a atividade das enzimas antioxidantes SOD e GPx estavam reduzidas em ratas grávidas e não grávidas que receberam L-NAME. A atividade da CAT não apresentou diferença entre os grupos. Em conclusão, uma redução na vasodilatação induzida pela Ang II associada a um aumento da vasoconstrição promovida por este peptídeo, sugerem uma contribuição do SRA no desenvolvimento das complicações características da PE observadas no modelo experimental de PE induzido por L-NAME. Do mesmo modo, a peroxidação lipídica e oxidação de proteínas aumentadas, assim como, as atividades enzimáticas antioxidantes reduzidas sugerem a contribuição de uma defesa antioxidante comprometida e um dano oxidativo aumentado para o desenvolvimento da hipertensão e disfunção endotelial, aumento da mortalidade fetal e retardo do crescimento intra-uterino observados no modelo de PE estudado. / Preeclampsia (PE), a systemic syndrome of pregnancy characterized by proteinuria and hypertension, is associated with significant morbidity and mortality to both mothers and fetuses, however its causes have not been completely clarified. Despite an expressive increase in renin-angiotensin system (RAS) activity in the normal pregnancy, blood pressure does not increase. Nevertheless, the role of RAS in PE is not well known. In PE, the reduction in intrauterine perfusion pressure promotes an increased release of reactive oxygen species, which may contribute to hypertension in pregnancy. In the present study, we investigated the role of the vascular RAS and the plasmatic, cardiorenal and placental oxidative stress to maternal cardiovascular regulation on normal pregnancy and in a animal model of preeclampsia which was induced by L-NAME. The bood pressure was increased in animals which received L-NAME. Pregnant + L-NAME rats had fat loss during pregnancy, increased number of death fetus, decreased number of fetus alive, lower total placental mass and lower pups weight. The vasodilator effect of acetylcholine (Ach) and angiotensin (Ang) II was reduced in pregnant + L-NAME and non-pregnant + L-NAME, otherwise, the vasodilator effect of nitroglycerine (NG) and the vasoconstrictor effect of phenilephrine (Phe) and Ang II were increased. The expression of AT1, AT2, ACE, ACE2 and eNOS were no significantly different among the four groups. The plasma levels of renin and bradykinin (BK) were increased in pregnant + L-NAME rats, while Ang 1-7 was reduced. The serum estradiol was increased in pregnant and pregnant + L-NAME rats. The levels of malondialdehyde and protein carbonyls were increased and activities of antioxidant enzymes SOD and GPx were lower in pregnant + L-NAME and non-pregnant + L-NAME animals, but CAT did now show significant difference among the four groups. In conclusion, the reduced vasodilator responde of Ang II associated to increased vasoconstrictor response of this peptide, suggest that RAS contribute to development of preeclampsia-like characteristics in this model of PE. Similarly, the increase of lipid peroxidation and protein oxidation, as the reduction of antioxidant activity suggest the involvement of a deficient mechanism of antioxidant defense and an increased oxidative damage contributing to development of hypertension, endothelial dysfunction, high fetus mortality and intrauterine growth restriction observed in this model of PE.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A hipertensão arterial sistêmica (HAS) caracteriza-se pelo aumento crônico da resistência vascular periférica, determinado essencialmente na microcirculação, que resulta de alterações vasculares funcionais e estruturais. Além disso, a redução da densidade arteriolar e capilar (rarefação da microcirculação) contribui para a elevação da pressão arterial na HAS. Nesse contexto, sabe-se que a hiperatividade do sistema nervoso simpático central está envolvida na fisiopatologia das alterações tanto funcionais quanto estruturais da HAS. No presente trabalho, investigamos os efeitos do tratamento crônico (28 dias) com anti-hipertensivos de ação central sobre a rarefação capilar funcional e/ou estrutural na pele, músculo esquelético e miocárdio de ratos espontaneamente hipertensos (SHR) adultos, modelo clássico de hipertensão arterial primária. Os ratos Wistar Kyoto (WKY) foram utilizados como controles normotensos. Foram utilizadas doses equipotentes de clonidina (0,1 mg/kg/dia), rilmenidina (1 mg/kg/dia) e moxonidina (10 mg/kg/dia), com relação ao efeito anti-hipertensivo. Também foram estudados os efeitos dos tratamentos sobre a massa ventricular esquerda. Para avaliação da densidade capilar funcional utilizamos microscopia por epi-iluminação e fluorescência e para avaliação da densidade capilar estrutural técnicas de marcação histoquímica dos capilares. Os resultados mostraram que houve aumento do número de capilares espontaneamente perfundidos (densidade funcional) na pele e no músculo esquelético de SHR tratados com todos os fármacos, com relação ao grupo SHR não tratado. Além disso, foi observada reversão da rarefação capilar estrutural no músculo esquelético de SHR com todas as drogas utilizadas. Por outro lado, não houve reversão da rarefação capilar estrutural no ventrículo esquerdo em nenhum grupo experimental. Finalmente, a hipertrofia do ventrículo esquerdo foi parcialmente revertida em SHR tratados com rilmenidina. Em conclusão, nossos resultados demonstraram que, além da redução da pressão arterial, a utilização de agentes anti-hipertensivos de ação central resulta na reversão de alterações microcirculatórias de ratos espontaneamente hipertensos e o uso de rilmenidina favorece a regressão da hipertrofia cardíaca. Os resultados também sugerem que a inibição da hiperatividade simpática central induz efeitos benéficos na microcirculação na hipertensão arterial. / Essential hypertension (EH) is characterized by chronic increases in peripheral vascular resistance, mainly resulting from functional and structural alterations of the microcirculation. Moreover, a reduction of arteriolar and capillary density (microvascular rarefaction) is involved in the increase of arterial pressure in EH. In addition, central sympathetic overactivity is involved in the pathophysiology of functional and structural alterations of the cardiovascular system in EH. In the present work, we investigated the effects of a long-term treatment (28 days) with centrally-acting antihypertensive drugs on functional and/or structural capillary rarefaction in the skin, skeletal muscle and heart of adult spontaneously hypertensive rats (SHR), a classical experimental model of EH. We also investigated the effects of the treatments on left ventricular mass in SHR. Wistar Kyoto rats were used as normotensive controls. We used equipotent anihypertensive doses of clonidine (0.1 mg/kg/day), rilmenidine (1 mg/kg/day) and moxonidine (10 mg/kg/day). Functional capillary density was evaluated using epi-illuminated fluorescence video-microscopy while structural capillary density was studied using a histochemical tracer of capillaries. Our results showed that there was an increase in the number of spontaneously perfused capillaries (functional density) in the skin and skeletal muscle of SHR in all treatment groups, when compared to the non-treated SHR group. Moreover, there was a reversion of structural capillary rarefaction in the skeletal muscle with all drug treatments. On the other hand, there was no reversion of structural capillary rarefaction of the left ventricle in any experimental group. Finally, left ventricular hypertrophy was partially reversed in the group of SHR treated with rilmenidine. In conclusion, our results showed that besides arterial pressure reduction, long-term treatment with centrally-acting antihypertensive drugs induces a reversal of microcirculatory alterations in SHR and rilmenidine favors the regression of left ventricular hypertrophy. The results also suggest that the modulation of central sympathetic overactivity induces beneficial effects on the microcirculation in the hypertensive disease.