Objetivou-se, neste trabalho, estudar a proporção de tecido conjuntivo existente na fração ventricular direita e esquerda do músculo cardíaco de cães, buscando, através da morfometria, dados referentes a inter-relação entre o tecido conjuntivo e o tecido muscular cardíaco, para o conhecimento das relações anátomo-funcionais da estrutura cardíaca, característica de determinados processos ligados a diminuição do trabalho do órgão. Utilizou-se 6 corações de cães SRD, machos e fêmeas, com idade entre 48 e 150 meses, pesando entre 18 e 30 Kg, sem alterações cardíacas, confirmado mediante exames eletrocardiográfico e ecocardiográfico. Preparou-se o material oriundo de três regiões ventriculares em relação a sua base, proximal, média e distal, tanto da face direita quanto da esquerda, segundo as técnicas histológicas convencionais e corados com Picrosirius red, Fucsina-Paraldeido e Tricromo de Gomori, para evidenciação das fibras conjuntivas. As lâminas foram analisadas com auxílio do Axioscópio Zeiss acoplado ao programa de análise de imagens KS-400 Zeiss. A quantidade de tecido conjuntivo no Ventrículo Esquerdo variou de 0,44 a 26,26%; no Ventrículo Direito variou de 0,97 a 21,18%; no ápice variou de 1,32 a 29,24% e no septo interventricular variou de 5,41 a 11,24%. Os resultados obtidos mostram que há uma complexa rede de fibras conjuntivas envolvendo as fibras do tecido muscular cardíaco e que sua quantidade e disposição é muito variada, dependendo da região estudada. / The aim of this study was to evaluate the ratio of connective tissue on the right and left ventricule of the cardiac muscle in the dog. Throughout of the morphometric study, we can gather information regarding the relationship between the connective and the muscle tissue, in order to find out the anatomic and functional relationship of the heart, which can provide information as for the diseases of the heart. In this study, we evaluated the heart of dogs, males and females, from 48 to 150 months-old, whose weight ranged from 18 to 30 kilograms, with no heart diseases confirmed by eletrocardographic and echocardiographic examinations. We got sample from 3 different regions of the ventricule, on the proximal, medial and distal faces, both on the right and left parts. We used the Picrosirius red and Gomori´s Trichrome to stain the material and bring out the connective fibers. We evaluated the slides by Axioscope Zeiss® with program KS400 analyse of images. The amount of connective tissue on the left ventricule ranged from 0,44 to 26,26%. On the right ventricule ranged from 0,97 to 21,18%. On the apex ranged from 1,32 to 29,24% and on the septo interventricular ranged from 5,41 to 11,24%. The results showed that there is a accureted connective fibers pattern surrounding the cardiac muscle tissue and it has na assorted amount and arrangement.

Orientadores: Denise Vaz de MAcedo, Rodrigo Hohl / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-17T12:28:54Z (GMT). No. of bitstreams: 1 Oliveira_RenatoBuscariollide_M.pdf: 1748495 bytes, checksum: 7afbaaae31e12db0ea4879f49812d3b5 (MD5) Previous issue date: 2011 / Resumo: O recurso do treinamento intensificado é comum no esporte de alto rendimento, uma vez que pode levar ao aumento no desempenho previamente atingido em um curto espaço de tempo. Esse treino pode ser manipulado através de aumentos substanciais nas cargas, duração, freqüência, intensidade e, principalmente, pela redução do período regenerativo. Por outro lado, já está bem documentado que essa intervenção pode resultar em perda do nível de desempenho anteriormente atingido. Embora existam diferentes nomenclaturas para descrever essa perda do desempenho em indivíduos previamente bem adaptados, utilizamos aqui a posição adotada em 2006 pelo Colégio Europeu de Ciências do Esporte, que denominou o período de treinamento intensificado de overtraining (OT) e os possíveis estados, de manutenção ou eventual melhora no desempenho de Overreaching Funcional (FOR), e de queda no desempenho de Overreaching Não Funcional (NFOR). Devido às limitações de se estudar o OT em seres humanos, desenvolvemos um protocolo em esteira para modelo animal (ratos Wistar) que gera os estados FOR e NFOR após um período de adaptação ao treinamento (TR). O objetivo do presente trabalho foi verificar qual a relação entre o estado do miocárdio e o nível de desempenho dos animais frente ao protocolo de OT. Para tanto, determinamos indiretamente a presença ou não de estresse oxidativo (EO) bem como alterações teciduais e eletrofisiológicas que pudessem mostrar prejuízo da função cardíaca. Assim, além do acompanhamento longitudinal do eletrocardiograma (ECG), ao término do protocolo foi feita análise histológica (Hematoxilina-Eosina/Sirius Red); quantificação de células apoptóticas (TUNEL - marcador de apoptose), dosagem de TBARS (marcador de peroxidação lipídica), e atividade das enzimas antioxidantes catalase (CAT), superóxido dismutase (SOD) e glutationa redutase (GR). Nossos resultados mostraram que não houve alterações nos parâmetros eletrocardiográficos ao longo do protocolo, nem nas análises histológicas e na dosagem de TBARS realizadas em cada um dos grupos de animais. A GR apresentou aumento significativo nos animais que treinaram (TR, FOR e NFOR) frente ao grupo controle (CO) enquanto a SOD, CAT e apoptose aumentaram de forma significativa somente no grupo NFOR. A manutenção dos níveis de TBARS e a ausência de alterações morfológicas ou eletrofisiológicas que poderiam comprometer a atividade contrátil do coração sugerem que o miocárdio adaptou-se positivamente ao treinamento mesmo no grupo NFOR. Todavia, o aumento da apoptose e das enzimas SOD e CAT no NFOR, sugerem uma maior produção de espécies reativas de oxigênio (EROS) neste grupo, que estaria mais susceptível a instalação de um quadro de estresse oxidativo. Portanto, apesar da queda de desempenho do grupo NFOR estar associada a outros fatores que não apenas o comprometimento do miocárdio, nossos dados apontam que a atividade física regular com alto volume deve ser conduzida com cautela e com avaliação periódica da função cardíaca / Abstract: The use of intensified training is common in high level sport, since it can lead to increases in the performance previously achieved. This training can be manipulated through substantial increases in loads, duration, frequency, intensity, and mainly by reducing the regeneration period. On the other hand, is well documented that this intervention may result in loss of the performance level previously attained. Although there are different classifications to describe this loss of performance in athletes previously well-adapted, we used here the position adopted in 2006 by the European College of Sport Science, which called the period of intensified training of overtraining (OT) and the possible states of maintenance or improvement in the performance of Functional Overreaching (FOR), and decrease in performance of Nonfunctional Overreaching (NFOR). Due to the limitations of studying the phenomenon of the OT in human beings, we developed an animal treadmill model (Wistar rats) that takes to the states FOR and NFOR after a period of adaptation to the training (TR). The objective of the present work was to verify the relation between the state of the myocardium and the performance level of the animals submitted to the OT protocol. So, we indirectly determined the presence or not of oxidative stress (EO) in the myocardium, as well as tissue and electrophysiological alterations that could harm the cardiac function. Therefore, we made the longitudinal accompaniment of electrocardiogram (ECG) and in the end of the protocol we made the histological analysis (HE/Sirius Red); the quantification of apoptotic cells (TUNEL), dosage of TBARS (marking of lipid peroxidation) and we measured the activity of the following antioxidant enzymes:catalase (CAT), superoxide dismutase (SOD) and glutathione redutase (GR). Our results had shown that there are no alterations in the electrocardiographic parameters (ECG), in the histological analyses and in the dosage of TBARS. The GR presented a significant increase in the animals that had trained (TR, FOR and NFOR) compared to Control Group (CO) while SOD, CAT and apoptosis had significant increase only in the NFOR. The maintenance of the TBARS levels and the absence of morphologic or electrophysiological alterations that could compromise the contractile activity of the heart, indicate that the myocardium was positively adapted to the training even in NFOR. However, the increase in enzymes SOD and CAT, and the increase of apoptosis in the NFOR, indicates that the production of reactive oxygen species (EROS) seems to be greater in this group, being imminent the installation of EO. Therefore, despite the drop in NFOR performance be associated with other factors than just the involvement of the myocardium, our data show that regular physical activity with high volume should be conducted with caution and with regular assessment of cardiac function / Mestrado / Mestre em Biologia Funcional e Molecular

Introdução: A hipertrofia ventricular esquerda é importante fator de risco de morbidade e mortalidade cardiovascular. Sua associação com variantes funcionais do sistema renina-angiotensina é controversa. Objetivos: Avaliar a associação entre massa ventricular esquerda e função sistólica e diastólica do ventrículo esquerdo e os polimorfismos inserção/deleção do gene da enzima de conversão da angiotensina e M235T do gene do angiotensinogênio. Métodos: Estudo observacional realizado numa amostra da população da cidade de Vitória (Espírito Santo), utilizando como base a metodologia do projeto Mônica da Organização Mundial da Saúde. Realizamos avaliação clínica, perfil antropométrico, análise laboratorial e ecocardiograma em 652 indivíduos previamente genotipados para polimorfismos da enzima de conversão da angiotensina e do angiotensinogênio. Analisamos massa ventricular esquerda indexada pela área de superfície corpórea e pela altura2,13. Classificamos o ventrículo esquerdo em padrões geométricos: padrão normal, remodelamento concêntrico, hipertrofia concêntrica e hipertrofia excêntrica. A função sistólica ventricular esquerda foi avaliada pela fração de ejeção medida ao modo unidimensional. A função diastólica foi analisada pelo fluxo mitral (onda E, onda A, relação E/A, tempo de desaceleração e tempo de relaxamento isovolumétrico) e pelo Doppler tecidual (velocidade miocárdica em região próxima ao anel mitral septal e lateral: ondas E e A e relação E/E). Resultados: A média de idade da população estudada foi 51 ± 10 anos sendo 59% dos participantes do sexo feminino e 20,8% obesos. Em nossa amostra, 47% dos indivíduos foram classificados como hipertensos. Não houve associação entre hipertensão arterial e os genótipos analisados. Após análise univariada, não encontramos associação entre os polimorfismos inserção/deleção da enzima de conversão da angiotensina e M235T do angiotensinogênio e índice de massa ventricular esquerda, padrões geométricos do ventrículo esquerdo, função sistólica avaliada pela fração de ejeção e os vários parâmetros de função diastólica analisados. / Introduction: Left ventricular hypertrophy is an important risk factor for cardiovascular morbidity and mortality. Its association with the reninangiotensin system genetic variants is controversial. Objectives: To assess the association between left ventricular mass, left ventricle systolic and diastolic functions, and polymorphisms of the insertion/deletion angiotensin converting enzyme and M235T angiotensinogen genes. Methods: Observational study in adults from Vitoria (Brazil) using the methodology of the Monica project of the World Health Organization. We performed clinical examination, anthropometric assessment, laboratory analysis and transthoracic echocargiography studies in 652 adults who were previously genotyped for polymorphisms of the angiotensin-converting enzyme and angiotensinogen. We measured left ventricular mass indexed to body surface area and height 2,13, left ventricular ejection fraction, and diastolic function using mitral flow and tissue Doppler. Left ventricle was classified into following geometric patterns: normal, concentric remodeling, concentric hypertrophy and eccentric hypertrophy. Left ventricular systolic function was assessed by ejection fraction by analysis of the M-mode echocardiogram. Diastolic function was assessed using mitral flow (E wave, A wave, E/A ratio, deceleration time and isovolumic relaxation time), and Doppler tissue imaging (mitral annulus velocity in septal and lateral region: E` and A` waves, and E/E`ratio). Results: Mean age of the studied population was 51±10 years; 59% of the subjects were women and 20,8% were obese. Forty seven percent of the individuals were classified as hypertensive. Hypertension was not associated with any of the studied genotypes. Univarate analysis showed no correlation between polymorphisms of the insertion/deletion angiotensin-converting enzyme and M235T angiotensinogen gene variants, left ventricular mass index, left ventricular geometric patterns, and systolic and diastolic functions. Taking together these data indicated no evidence for the association of ACE and angiotensinogen gene variants with cardiac mass and function assessed by echocardiography.

A presente investigação científica visa estabelecer biometricamente a análise comparativa dos elementos estruturais e ultra-estruturais que compõe o músculo cardíaco, em cães sadios e diabéticos, avaliando a proporção existente entre a quantidade de tecido conjuntivo e a de fibras musculares cardíacas, estudando a densidade vascular presente no músculo cardíaco e quantificando a proporção de organelas presentes naquelas fibras. Utilizou-se doze corações de cães, machos e fêmeas, sendo seis animais sadios e seis animais diabéticos, onde efetuou-se a mensuração do coração em seus eixos longitudinal e transversal e, ainda as espessuras das paredes dos ventrículos e do septo interventricular. Submeteu-se o músculo cardíaco ao estudo de seus elementos estruturais a partir do emprego da microscopia de luz analisados com auxílio de Programa de Análise de Imagem e Morfometria KS-400 Zeiss®. Já, os elementos ultra-estruturais foram investigados através do emprego da microscopia eletrônica de transmissão. Os dados obtidos foram tratados estatisticamente considerando-se as variáveis relativas ao sexo na presença ou não de diabetes. / The present scientific inquiry aims at biometrically to establish a comparative analysis of the structural and extreme-structural elements that composes the cardiac muscle in healthy and diabetic dogs. This will be given evaluating the existing ratio enters the conjunctive amount of fabric and of cardiac muscular staple fibers, studying the present vascular density in the cardiac muscle and still quantifying the ratio of organelles existents in those staple fibers. For in such a way we will use twelve hearts of dogs, males and females, being six healthy animals and six diabetic animals. We will effect the mensuration of the heart in its longitudinal and transversal axles, still the thicknesses of the walls of the ventricles and septum to interventricular, with digital aid of electronic paquimeter. The cardiac muscle was submitted to the study of its structural elements using Microscopy of light analyzed with aid of optic microscope Axioscópio Zeiss® and the Program of Analysis of Image and Morfometric Ks-400 Zeiss®. Already, the extreme-structural elements was investigated through the electronic Microscopy of transmission, evaluating themselves thus the ultra fine cuts from the attainment of the electromicrografics gotten in electron microscope Jeol 1010. The gotten data was treated statistically considering the relative variable the sex, in relation to the healthy animals and those diabetic ones.

O overreaching não funcional (NFOR) induzido por consecutivas sessões de treinamentos intensos intercaladas por períodos insuficientes de recuperação, está associado com inflamação e consequente prejuízo da via de sinalização insulínica em músculos esqueléticos de camundongos. Sabe-se que o miocárdio também é capaz de produzir tais proteínas inflamatórias associadas ao comprometimento da via hormonal e que alterações na atividade do receptor insulínico cardíaco levam à forçadas modificações na utilização dos substratos energéticos com prejuízos na mecanoenergética cardíaca predispondo o miocárdio à diversas injúrias. No entanto os efeitos do NFOR nas vias inflamatórias e insulínica cardíaca ainda não foram investigados. Assim, o presente estudo tem como objetivo avaliar os efeitos do NFOR no conteúdo de glicogênio cardíaco e ativação de proteínas relacionadas às vias insulínica e inflamatória. Os animais foram divididos em 6 grupos: Naive, Controle, Treinado, e os grupos submetidos ao protocolo de overtraining em declive (OTR/down), aclive (OTR/up) e sem inclinação (OTR). As especificidades das contrações musculares induziram diferentes adaptações cardíacas. Os grupos OTR e OTR/up não apresentaram sinais de inflamação além de superexpressarem a via insulínica, por outro lado, o grupo OTR/down apresentou inflamação cardíaca de baixo grau, contudo, sem queda no conteúdo de pIR. Todos os protocolos de overtraining induziram elevação no conteúdo de glicogênio cardíaco acompanhado de expressiva queda da pAMPK. Os resultados do presente trabalho nos trazem, portanto, a hipótese de que o tecido cardíaco apresente uma maior resistência à inflamação viabilizando dessa forma a melhora da resposta insulínica e acúmulo do glicogênio cardíaco a fim de fornecer a energia necessária ao extenuante exercício físico evitando a lipotoxicidade cardíaca. Por outro lado, a queda da AMPK consequente do excessivo acúmulo de glicogênio cardíaco pode predispor o miocárdio à diversas injúrias, sendo necessários mais estudos na área. / Non-functional overreaching (NFOR) induced by consecutive intense training sessions interspersed by insufficient periods of recovery is associated with inflammation and a consequent impairment of the insulin signaling pathway in skeletal muscle of mice. It is known that the myocardium is also capable of producing such inflammatory proteins associated with the impairment of the hormonal pathway and that changes in cardiac insulin receptor activity lead to forced modifications in the use of energetic substrates with losses in cardiac mecanoenergética predisposing the myocardium to various injuries. However, the effects of NFOR on inflammatory and cardiac insulin pathways have not been investigated yet. Thus, the present study aims to evaluate the effects of NFOR on cardiac glycogen content and activation of proteins related to insulin and inflammatory pathways. The animals were divided into 6 groups: Naïve, Control, Trained, and the groups submitted to the overtraining protocol in decline (OTR/down), uphill (OTR /up) and without inclination (OTR). The specificities of muscle contractions induced different cardiac adaptations. OTR and OTR/up groups showed no signs of inflammation and an over expressive of the insulin pathway; on the other hand, the OTR/down group presented low-grade cardiac inflammation, however, without any decrease in the pIR content. All overtraining protocols induced elevation in cardiac glycogen content accompanied by significant drop in pAMPK. The results of the present work hypothesize that the cardiac tissue presents a greater resistance to inflammation, thus enabling the improvement of the insulin response and the accumulation of cardiac glycogen in order to provide the necessary energy to the strenuous physical exercise avoiding cardiac lipotoxicity. On the other hand, the decrease in AMPK due to the excessive accumulation of cardiac glycogen may predispose the myocardium to several injuries, and further studies in the area are required.

Diversos estudos indicam que a deficiência de estrógeno aumenta a incidência de doenças cardiovasculares em mulheres na pós-menopausa. Os efeitos decorrentes da deprivação de estrógeno no miocárdio ainda não estão totalmente esclarecidos. Estudos têm evidenciado efeitos benéficos da atividade física no sistema cardiovascular, em qualquer condição, em especial na menopausa. Utilizando ratos Wistar, como modelo experimental, os objetivos deste trabalho são: a) verificar se a ooforectomia e a atividade física produzem alterações no miocárdio do ventrículo esquerdo, b) verificar se a realização do exercício físico aeróbico tem efeito sobre essas alterações. Para a realização deste estudo foram utilizadas 15 ratas com 6 meses de idade, da linhagem Wistar, distribuídas em 3 grupos de 5 ratas cada: GC- Ratas com 6 meses de idade sem ooforectomia e sem atividade física; GS- Ratas com 6 meses de idade com ooforectomia bilateral sem atividade física; GA- Ratas com 6 meses de idade com ooforectomia bilateral que realizaram atividade física (corrida em esteira) durante 3 meses. Os animais dos 3 grupos foram eutanasiados com 9 meses de idade. A avaliação foi realizada através de microscopia de luz e estereologia. Os cortes histológicos foram corados por: Hematoxilina-Eosina e Picrosírius. Na parede do ventrículo esquerdo foram estimadas as densidades de volume dos cardiomiócitos, do tecido conjuntivo e a densidade de comprimento e densidade de volume dos vasos intramiocárdicos. Foi estimado o número total de núcleos de cardiomiócitos e sua densidade numérica foi estimada através do método disector. Os dados quantitativos dos três grupos foram estatisticamente comparados através do ANOVA e teste de Tukey. Os resultados mostraram que houve um aumento de peso nos animais do GS e GA em relação ao GC. Quanto ao treinamento, os animais do GA tiveram melhor rendimento nos TEMs. Quanto ao volume do VE, observamos uma diminuição, embora não significante, nos animais do GS e GA em relação ao GC. A densidade de volume dos vasos intramiocárdicos foi maior no GC que no GA. As diferenças não foram estatisticamente significantes em relação à ooforectomia e ao exercício físico para os parâmetros: densidade de volume dos cardiomiócitos e do tecido conjuntivo, densidade de comprimento dos vasos intramiocárdicos, densidade numérica dos núcleos dos cardiomiócitos, número total de núcleos de cardiomiócitos e densidade numérica do colágeno. Esses dados nos levam a concluir que a ooforectomia acarreta alterações no volume do ventrículo esquerdo e a atividade física diminui a densidade de volume dos vasos intramiocárdicos. Quanto aos outros itens, nem a ooforectomia, nem a atividade física, isoladamente ou associada, parecem influenciar de maneira significativa nestes dados. / Severals studies indicate that the estrogen deficiency increase the incidence of the cardiovascular diseases in women in the post-menopausal period. The effects of the estrogen deprivation in the myocardium still remain unclear. Studies have proved beneficial effects of the physical activity in the cardiovascular system, especially in the menopause. Using Wistar rats, as an experimental model, the aims of this work are: a-) to check if the ooforectomy and the physical activity produce alterations in the left ventricle of the myocardium; b-) to check if the aerobic exercise realization affects these alterations. To achieve these goals it was used 15 Wistar rats of 6 months of age, distributed in 3 groups of five rats each: Control group- Rats with six months of age without ooforectomy and physical activity; GS- Rats with six months of age with ofoorectomy bilateral and without physical activity and, GA- Rats with six months of age with ooforectomy bilateral and physical activity during 3 months. Al rats were euthanasied with 9 months of age. The results were obtained by using light microscopy were and stereology. The histological section was stained with Hematoxylin and Eosin, and Picrosirius stain. On the wall of the left ventricle were estimated the density of volume of the cardiomiocyt, of the connective tissue and the density of length and the density of volume of the intramyocardial vessels. It was estimated the total number of nuclei of cardiomiocyt and its numerical density was estimated a cross the disector method. The data of the three groups were statistically compared for the ANOVA and Tukey´s test. The results showed that there was an increase in the weight in the animals of GS and of GA. In relation to training, the animals of GA obtained the best income in the TEMs. In relation to the volume of the left ventricle, it was observed a decrease, although not significant, in the animals of GS and GA. The density of volume of the intramyocardial vessels was higher in the GC than GA. In relation to the ooforectomy and the physical exercise for the items: density of volume of the cardiomiocyt and of the connective tissue, density of length of the intramyocardial vessels, numerical density of nuclei of cardiomiocyt, total number of nuclei of cardiomiocyt and numerical density of collagen, the differences werent significant. We can conclude that the ooforectomy result in changes in the volume of the left ventricle and that the physical activity decrease the density of volume of the intramyocardial. In relation to the other items, neither the ooforectomy, neither the physical activity, alone or together, seem doesn\'t affect these data.

Submitted in fulfillment of the requirements for the Degree of Masters in Technology: Cardiology, Durban University of Technology, 2012. / Cardiomyopathies and their resultant heart failure (HF) remain a major cause of cardiovascular morbidity and mortality (Wood and Picard, 2004). Idiopathic dilated cardiomyopathy (IDCMO) is a primary myocardial disease of unknown cause, characterized by left ventricular (LV) or biventricular dilatation and impaired myocardial contractility. Dilated cardiomyopathy (DCMO), along with rheumatic heart disease and hypertension (HPT), is one of the leading causes of HF in Africa. In fact, in an epidemiology study of 884 patients in Soweto, IDCMO was the second major cause of HF. Thirty five percent of patients in the study, with HF, had IDCMO (Sliwa, Damasceno, Mayosi, 2005). Methodology: Patients referred to the cardiomyopathy (CMO) clinic at Chris Hani Baragwanath hospital, situated in the echocardiographic lab, were recruited, provided they satisfied the exclusion and inclusion criteria and were enrolled after obtaining voluntary informed consent. From May 2009 to September 2010, 70 patients with IDCMO were recruited for this trial. Patients with DCMO were identified by means of echocardiographic criteria which included a left ventricular ejection fraction (LVEF) of less than 45% and an end diastolic dimension (EDD) of greater than of 52 mm (2D in long parasternal axis). Results: In the present study the prevalence of left ventricular (LV) thrombus in patients with IDCMO was 18.6%. When using Univariate logistic regression, the only independent predictors of LV thrombus formation was LVEF and age. However, when multivariate logistic regression analysis was applied to the data, the only predictor with a significant association was age. The reason for this is not clear. It is postulated that perhaps younger patients have differences in the pathophysiology of their disease such as a greater smoldering inflammatory component which may therefore predispose them to thrombus formation. For example the presence of IL-6 may be important in the formation of LV clot in cases of LV dysfunction (Sosin, Bhatia, Davis, Lip, 2003). The association between LVEF and LV thrombus was borderline significant. Conclusion: The prevalence of LV thrombus formation in this cohort of patients with IDCMO was 18.6%. Echocardiographic parameters alone cannot predict which patients are more likely to develop thrombus formation. / National Research Foundation / M

Abstract Interest in off-pump coronary surgery and ischaemic preconditioning has been increasing. The aim of this study was to evaluate surrogate indicators of haemodynamic, myocardial, and cerebral outcome during off-pump surgery and preconditioning. Haemodynamics and myocardial preservation were monitored in a pilot study of twelve patients undergoing off-pump coronary surgery. Indicators of myocardial metabolism and tissue injury as well as cerebral damage were evaluated in a randomized study of thirty-three patients undergoing on-pump (11) or off-pump surgery with (11) or without (11) preceding myocardial ischaemic preconditioning for five minutes followed by reperfusion for five minutes. The pilot study showed minimal haemodynamic changes and myocardial derangements during off-pump surgery as evaluated intraoperatively based on transcardiac differences of ATP degradation products and lactate and postoperatively based on MB mass of creatine kinase and troponin T. In the following studies, myocardial ischaemic metabolism was evaluated intraoperatively by measuring transcardiac differences of ATP degradation products, lactate, and pH, which increased significantly from the baseline values in all study groups. However, the maximum values of lactate and pH were significantly higher in the cardiopulmonary bypass group (p = 0.02 and p = 0.007, respectively). There were no statistical differences between the preconditioning and non-preconditioning groups. Myocardial tissue injury was evaluated by postoperative leakage of MB mass of creatine kinase and troponin I. Their peak values were significantly higher (p < 0.001 and p = 0.008) after cardiopulmonary bypass (15.1 μg/l and 13.8 μg/l) than after off-pump surgery without preconditioning (6.3 μg/l and 5.2 μg/l). The respective values were 14.8 μg/l and 7.4 μg/l after preconditioning, and there were no statistically significant differences between the off-pump groups with and without preconditioning. Cerebral damage was evaluated based on the intra- and postoperative serum concentrations of neuron-specific enolase, which were corrected with respect to haemolysis. The corrected values were significantly higher after on-pump than off-pump surgery (p = 0.003 and p = 0.005). In conclusion, multi-vessel off-pump coronary artery surgery is a haemodynamically feasible procedure offering better myocardial preservation compared to on-pump surgery. Ischaemic preconditioning of the myocardium does not seem to improve myocardial preservation in off-pump surgery. The slightly lower levels of neuron-specific enolase also suggest less cerebral damage.

Muscarinic acetylcholine receptors (mAChRs) are G-protein coupled receptors that mediate various actions of Acetylcholine (ACh) in the central nervous system and peripheral nervous system. In mammals, five distinct mAChR subtypes (M1-M5) have been recognised with the M2 subtype being predominantly present in the heart. The mAChR antagonists are routinely used for the treatment of various pathophysiological conditions including respiratory conditions. However, it has been postulated that mAChR antagonists may increase morbidity and mortality in chronic obstructive pulmonary disorder (COPD) and asthma patients with underlying cardiovascular disease, raising concerns regarding the cardiovascular safety of these agents. The current study was therefore undertaken to investigate the effects of individual mAChR antagonists in the setting of myocardial ischaemia reperfusion injury and oxidative stress models. We also investigated whether the inhibition of the mitochondrial permeability transition pore (MPTP) with cyclosporine-A (CsA) in the presence and absence of individual mAChR antagonists provided protection against ischaemia reperfusion injury. Furthermore, we also aimed to investigate the intracellular signalling pathway associated with mAChRs antagonists mediated myocardial injury under the stress conditions. Langendorff results showed that the non-selective M1-M3 mAChR antagonist, ipratropium bromide, the M2 mAChR antagonist, AF-DX 116 and the M3 mAChR antagonist, DAU 5884 significantly increased the infarct size to risk ratio of the heart in conditions of ischaemia and reperfusion. Detrimental effects of AF-DX 116 and DAU 5884 were abrogated by co-treatment of these drugs with mAChR agonist, acetylcholine (ACh) and/or CsA. Cell viability data of isolated cardiac myocytes revealed that AF-DX 116 and DAU 5884 caused a concentration dependent decrease in the viability of cardiac myocytes as well as causing a reduction in the time taken to depolarisation and hypercontracture under oxidative stress. AF-DX 116 and DAU 5884 significantly increased the levels of p-SAPK/JNK and decreased the levels of p-Akt and p-ERK. In addition, ACh and CsA showed to activate p-Akt and p-ERK. To conclude, the data suggest that AF-DX 116 and DAU 5884 caused cardiotoxicity at cellular, tissue and protein level in conditions of ischaemia reperfusion injury and oxidative stress. Furthermore, inhibition of the mitochondrial transition pore with CsA protected against the AF-DX 116 and DAU 5884 induced injury via activation of the pro-survival proteins, p-Akt and p-ERK.

Diabetes mellitus has been associated with both clinical and experimental cardiac dysfunction. Diabetic cardiomyopathy which is characterized by depressed cardiac contractility is accompanied by a variety of biochemical changes in Ca⁺⁺ metabolism. This cardiomyopathy may occur in the presence of normal coronary arteries and normal blood pressure. However, some studies have shown that hypertension is more prevalent among diabetics and can aggravate the cardiovascular abnormalities associated with diabetes. To understand the mechanisms of diabetic cardiomyopathy and consequences of combined hypertension and diabetes, experiments were designed to measure cardiac tissue responses to various inotropic agents in experimental diabetes. Six weeks following streptozotocin (STZ) administration, Wistar, spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats exhibited the 'classical signs' of diabetes which included: hyperglycemia, hypoinsulinemia, hyperlipidemia (except in WKY), and hypothyroidism. Decreased basal atrial rate and increased basal developed force (BDF) suggest a depressed SA node function and an alteration of Ca⁺⁺ utilization by diabetic ventricles. Decreased post quiescent potentiation (PQP) values (except in WKY) in ventricular tissues suggest a diminished amount of releasable Ca⁺⁺ from sarcoplasmic reticulum (SR). Decreased post stimulation potentiation (PSP) values in SHR papillary muscles (PM) are probably suggestive of a depressed sarcolemmal Na⁺-Ca⁺⁺ exchange function in this tissue. Diabetic rats show subsensitivity to β-adrenergic stimulation in ventricular tissues, supersensitivity and hyperresponsiveness to Ca⁺⁺ and α-adrenergic stimulation (except in WKY) in ventricular tissues and left atria (LA) and supersensitivity to BAY K 8644 in SHR LA and hyperresponsiveness to verapamil in ventricular strips. These alterations may be attributed to a change in receptor number and/or a post receptor alteration. Ryanodine decreased the PQP of Wistar and SHR PM and SHR LA in both controls and diabetics. It especially abolished PQP in SHR diabetic tissues, but had no effect on WKY tissues, which may suggest a difference in the SR function in these tissues. SR with impaired Ca⁺⁺ uptake may contribute to these phenomena in diabetic rats. Ryanodine also diminished (PQP + BDF) of SHR LA and (PQP/BDF) of Wistar and SHR PM, ˙but had no effects on control and other diabetic tissues. It appears that ryanodine has some influence on the Na⁺-Ca⁺⁺ exchange generated by sarcolemma (SL) of certain diabetic tissues. Further experiments are required to clarify this. SHR diabetic rats had greater changes in most of the measurements such as hyperlipidemia, depressed PQP and PSP values, and altered drug responses. This model exhibited very high mortality as compared to Wistar and WKY diabetic rats. As has been shown previously, the combination of hypertension and diabetes exerts a synergistic effect on the cardiac dysfunction in this model, and that altered lipid metabolism, SL and SR function are all involved in the development of cardiomyopathy. WKY diabetic rats, on the other hand, exhibited no significant changes in blood lipids, or in response to phenylephrine or to Ca⁺⁺ (LA) stimulation. Lack of change in these factors may explain the relatively normal cardiac function of this model as measured previously. / Pharmaceutical Sciences, Faculty of / Graduate