<p>This dissertation aims to demonstrate the feasibility of direct infarct visualization using 3D medical ultrasound. The dissertation proceeds by providing the first ever demonstration of fully-sampled 3D ultrasonic speckle tracking using raw B-Mode data of the heart. The initial demonstration uses a Cramer-Rao lower bound limited displacement estimator. The dissertation then proceeds to develop an implementable method for biased time-delay estimation. Biased time-delay estimation is shown to surpass the traditional limits described by the Cramer-Rao lower bound in a mean square error sense. Additional characterization of this new class of estimator is performed to demonstrate that with easily obtainable levels of prior information it is possible to estimate displacements that do surpass the Cramer-Rao lower bound. Finally, using 2D and 3D realizations of biased displacement estimation (Bayesian speckle tracking) the passive strain induced in the ventricle walls during atrial systole is shown to be sufficient to distinguish healthy and chronically infarcted myocardium.</p> / Dissertation

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2018-06-21T18:29:06Z No. of bitstreams: 1 Eduardo Tadeu Santana.pdf: 3781492 bytes, checksum: 5fb6eff774c2c39d42bab565b9e807ef (MD5) / Made available in DSpace on 2018-06-21T18:29:06Z (GMT). No. of bitstreams: 1 Eduardo Tadeu Santana.pdf: 3781492 bytes, checksum: 5fb6eff774c2c39d42bab565b9e807ef (MD5) Previous issue date: 2015-12-18 / The ligation of the anterior descending coronary artery is the most commonly used experimental model to induce myocardial infarction (MI) in rodents. A high mortality in the acute phase and the heterogeneity of the size of the MI obtained are drawbacks recognized in this model. In an attempt to solve the problem, our group recently developed a new MI experimental model which is based on application of myocardial ablation radio-frequency currents (AB-RF) that yielded MI with homogeneous sizes and significantly reduce acute mortality. In addition, cardiac structural and functional changes aroused by AB-RF were similar to those seen in animals with MI induced by coronary artery ligation. Herein, we evaluated modifications of gene expression that govern post-MI milieu in occlusion and ablation models. We analyzed 48 mRNA expressions of 9 different signal transduction pathways (signs of cell survival and metabolism, matrix extracellular, cell cycle, oxidative stress, apoptosis, calcium signaling, hypertrophy markers, angiogenesis and inflammation) in rat left ventricle 1 week after MI promoted by either coronary occlusion and AB-RF. Furthermore, high-throughput miRNA analysis was also assessed after either MI procedures. Interestingly, mRNA expression levels and miRNA expressions were similar in both models after MI, with few specificities in each model. This study reports for the first time the global changes in rat cardiac mRNA and miRNA contents after two different MI procedures and identifies key signaling regulators modulating the pathophysiology of these two models that might culminate in heart failure. Furthermore, these analyses would enhance our present knowledge regarding altered pathophysiology of these two different MI models. / A ligadura da artéria coronariana descendente anterior é o modelo experimental mais comumente usado para induzir o infarto do miocárdio (IM) em roedores. Entretanto, uma elevada taxa de mortalidade na fase aguda e a heterogeneidade do tamanho do IM obtidos são desvantagens reconhecidas neste modelo. Em uma tentativa de resolver o problema, o nosso grupo desenvolveu recentemente um novo modelo experimental de insuficiência cardíaca que se baseia na aplicação de correntes de radiofrequência ablação do miocárdio (AB-RF), produzindo IM com tamanhos homogêneos e com significativamente redução da mortalidade aguda. Além disso, alterações estruturais e funcionais do coração deste modelo foram semelhantes aos observados em animais com infarto induzido por ligação da artéria coronária. Aqui, nós avaliamos modificações da expressão de RNA mensageiro (RNAm) de genes após IM induzido por oclusão e ablação. Foram analisadas as expressões de 48 RNAm de 9 diferentes vias de transdução de sinal (sinais de sobrevivência celular e metabolismo, matriz extracelular, ciclo celular, estresse oxidativo, apoptose, sinalização de cálcio, marcadores de hipertrofia, angiogênese e inflamação) no ventrículo esquerdo de ratos uma semana após o IM promovido por oclusão coronária e AB-RF. Além disso, a análise de alto rendimento de miRNA também foi avaliada após ambos procedimentos de IM. Curiosamente, os níveis de expressão de RNAm e expressão de miRNA foram semelhantes em ambos os modelos após o IM, com algumas especificidades em cada modelo. Este estudo relata pela primeira vez as mudanças globais nos conteúdos de RNAm e miRNA após dois procedimentos de IM diferentes e identifica reguladores que podem modular a fisiopatologia desses dois modelos, culminando em insuficiência cardíaca.

Thesis (M.Sc. (Clinical Pathology))--Mahidol University, 1978.

Au niveau clinique, il a été observé que de 15 à 30 % des patients qui ont subi un infarctus du myocarde développent une dépression majeure. De plus, la population atteinte de dépression post-infarctus présente un risque de mortalité de trois à quatre fois plus élevé, et ce, en comparaison avec la population non dépressive post-infarctus. Dans un modèle de rat développé pour étudier la dépression post-infarctus, des cellules apoptotiques ont été retrouvées au niveau du système limbique. Il apparaît que les cytokines seraient en partie responsables de cette mort cellulaire qui relie le cœur en ischémie et le système nerveux central. Donc, les objectifs de cette thèse sont : 1) de caractériser spatialement et temporellement la survenue de la mort cellulaire par apoptose dans les structures du système limbique du rat, à la suite d’un infarctus du myocarde ; 2) de déterminer l’effet de l’anti-inflammatoire celecoxib sur cette apoptose observée au niveau de l’amygdale et de déterminer l’implication de l’enzyme COX-2 ; 3) de déterminer l’implication de la cytokine pro-inflammatoire TNF-α dans l’apoptose observée au niveau des structures du système limbique du rat, à la suite d’un infarctus du myocarde. Afin d’atteindre ces objectifs, les rats ont subi une ischémie de 40 minutes, suivi d’une période de reperfusion qui varie d’un protocole à l’autre (15 minutes, 24, 48, 72 heures ou 7 jours). De plus, en fonction du protocole, ces rats ont été traités avec soit du célécoxib (inhibiteur sélectif de la COX-2), soit avec du PEG sTNF-R1 (inhibiteur du TNF-α). À la suite de ces protocoles, les rats ont été sacrifiés, la taille de l’infarctus a été déterminée et les différentes structures cérébrales du système limbique prélevées. Des tests biochimiques propres à chaque protocole ont été réalisés afin de documenter l'apoptose. Il a alors été observé qu’aucun des deux traitements ne présentait d’effet sur la taille de l’infarctus. L’étude de l’apoptose dans le système limbique a révélé que : 1) le processus apoptotique se mettait en place dans l’hippocampe dès les 15 premières minutes de reperfusion suivant l’infarctus du myocarde et que ce processus était spatialement dynamique dans le système limbique jusqu’au septième jour postreperfusion ; 2) il est apparu que la COX-2 était impliquée dans l'apoptose du système limbique ; 3) il a été observé que le TNF-α périphérique était impliqué dans ce processus apoptotique après 72 heures de reperfusion en activant la voie extrinsèque de l'apoptose. Ces résultats ont permis de caractériser la survenue de l’apoptose au niveau du système limbique chez le rat à la suite d’un infarctus du myocarde et de documenter l'implication de la COX-2 et du TNF-α dans ce processus. Bien que ces résultats n’apportent pas de schémas thérapeutiques clairs ou de mécanismes physiopathologiques globaux ces derniers permettent une meilleure compréhension de la relation existante entre le cœur et le système nerveux central dans le cadre de l’infarctus du myocarde. De manière moins spécifique ils précisent la relation entre le système inflammatoire et le système nerveux central. / About 15 to 30% of clinical patients with myocardial infarction develop major depression. This population is three to four times more vulnerable to fatalities such as death when compared to the non depressed post-myocardial population. In a rat model, developed in order to study post myocardial infarct depression, apoptotic cells within the limbic system have been found. It has been shown that cytokines could be responsible for the cell death linking the ischemic heart to the central nervous system. Thus, the aims of this thesis are: 1) to characterize the spatial time course of the apoptotic cell death within the limbic system, following a myocardial infarct, in a rat model; 2) to determine the effect of the anti-inflammatory celecoxib on this apoptosis in the amygdala and determine the COX-2 enzyme’s implication; 3) to determine the implication of the pro-inflammatory cytokine TNF-α in the apoptosis observed within the limbic system, following a myocardial infarct, in a rat model. In order to achieve these goals, rats were submitted to 40 minutes of myocardial ischemia followed by a variable reperfusion period (15 minutes, 24, 48, 72 hours or 7 days). Moreover, depending on the protocol, rats were treated with celecoxib (COX-2 selective inhibitor), or with PEG sTNF-R1 (TNF-α inhibitor). At the end of each respective reperfusion period, rats were sacrificed, infarct size was determined and the different structures of the limbic system were dissected for further analysis. Biochemical tests, specific to each protocol were performed in order to characterize this apoptosis. With respect to obtained results, we observed that the infarct size was impacted by none of the two treatments. Apoptosis study within the limbic system revealed that: 1) the apoptotic process was activated in the hippocampus area within the first 15 minutes of reperfusion and this process was spatially dynamic in the limbic system until the seventh day of reperfusion; 2) it appeared that COX-2 was implicated in the apoptosis in the limbic system; 3) peripheral TNF-α was implicated in the apoptotic process after 72 hours of reperfusion by activating the extrinsic and intrinsic pathways of apoptosis. These results allowed characterization of apoptosis within the limbic system, in a rat model, following a myocardial infarct and the establishment of the implication of COX-2 and TNF-α in this process. Although these results do not provide any clear therapeutic schemas or global physiopathological mechanisms, they allow a better comprehension of the existing relationship between the heart and the central nervous system within the myocardial infarct context. To a less specific extent these results bring more information on the relationship between the inflammatory system and the central nervous system.

Abstract Oxygen is essential for aerobic organisms, as shortage of oxygen (hypoxia) can induce cellular dysfunctions and even cell death, leading to tissue damage and decreased viability of the organism. Oxygen homeostasis is regulated delicately by several mechanisms, the major one being the hypoxia-inducible factor (HIF) pathway that is evolutionarily conserved. HIFα subunits are regulated in an oxygen-dependent manner via three HIF prolyl 4-hydroxylases (HIF-P4Hs). In the presence of oxygen HIF-P4Hs modify HIFα, which leads to its degradation, whereas in hypoxia the HIF-P4H enzymes cannot function and HIFα is stabilized. HIF regulates more than 300 genes that enhance oxygen delivery from the lungs to tissues and reduce oxygen consumption in tissues, such as those for erythropoietin and vascular endothelial growth factor. When a tissue suffers from hypoxia caused by a circulatory restriction, the situation is called ischemia. In this study we used a genetically modified HIF-P4H-2 hypomorph mouse line that expresses 8% of the wild-type Hif-p4h-2 mRNA in the heart and 19% in skeletal muscle, and has HIFα stabilization in both tissues. We showed that chronic HIF-P4H-2 deficiency leads to protection against acute ischemic injury both in the heart and in skeletal muscle. The protection was mainly due to enlarged capillaries and better perfusion in both tissues. Hypoxia is known to decrease body weight. The observation of the HIF-P4H-2 deficient mice being leaner than their wild-type littermates led us to study their body constitution, metabolism and adipose tissue in detail. We discovered that chronic HIF-P4H-2 deficiency protects against obesity and several metabolic dysfunctions including diabetes and metabolic syndrome. These beneficial outcomes were mimicked when a pharmacological pan-HIF-P4H inhibitor was administered to wild-type mice. In these studies we showed that pharmacological HIF-P4H-2 inhibition may provide a novel treatment for diseases such as acute myocardial infarction, peripheral artery disease and metabolic disorders. / Tiivistelmä Happi on edellytys aerobisen eliön, kuten ihmisen, elämälle; hapen niukkuus (hypoksia) voi johtaa monenlaisiin solun toimintahäiriöihin, jotka voivat edelleen aiheuttaa solun kuoleman, kyseisen kudoksen vaurion, ja lopulta eliön elinkyvyn heikkenemisen. Happitasapainoa säädellään monilla menetelmillä, joista merkittävin on hypoksiassa indusoituvasta tekijästä (HIF) riippuvainen reitti, joka on evoluutiossa säilynyt. HIFα alayksiköitä säätelee hapesta riippuvaisesti kolme HIF prolyyli 4-hydroksylaasia (HIF-P4Ht). Hapen läsnä ollessa HIF-P4H on aktiivinen ja johtaa HIFα:n hajottamiseen, kun taas hypoksiassa HIF-P4H entsyymit eivät voi toimia ja siten HIFα stabiloituu. HIF säätelee yli 300 geeniä, jotka edistävät hapen kuljetusta ja pääsyä keuhkoista kudoksiin sekä vähentävät hapenkulutusta. Näitä geenejä ovat mm. erytropoietiini sekä vaskulaarinen endoteelikasvutekijä. Kudoksen heikentyneestä verenkierrosta johtuvaa hapenpuutetta kutsutaan iskemiaksi. Tässä tutkimuksessa käytimme geneettisesti muunneltua HIF-P4H-2 hypomorfi-hiirikantaa, joka tuottaa Hif-p4h-2 lähetti-RNA:ta sydämessä vain 8 % ja luurankolihaksessa 19 % villityypin määrästä, ja jolla on HIFα stabiloituneena molemmissa kudoksissa. Osoitimme, että krooninen HIF-P4H-2:n puute suojaa sekä sydäntä että luurankolihasta akuutissa iskemiassa. Vaikutus johtui pääasiassa suuremmista kapillaareista ja paremmasta perfuusiosta molemmissa kudoksissa. Aikaisempien tutkimusten perusteella tiedetään, että hypoksia alentaa painoa. Huomio siitä, että HIF-P4H-2 puutteiset hiiret ovat hoikempia kuin villityypin sisaruksensa, johti meidät tutkimaan hiirten kehon koostumusta, aineenvaihduntaa ja rasvakudosta tarkemmin. Tutkimuksissamme selvisi, että krooninen HIF-P4H-2:n puute suojaa lihavuudelta ja monelta aineenvaihdunnan häiriöltä kuten sokeritaudilta ja metaboliselta oireyhtymältä. Nämä edulliset vaikutukset toistuivat, kun annoimme villityypin hiirille pan-HIF-P4H inhibiittoria. Kaiken kaikkiaan, näissä tutkimuksissa osoitimme, että lääkkeellinen HIF-P4H-2:n estäminen voi tarjota uuden keinon sydäninfarktin, luurankolihasiskemian ja aineenvaihdunnan häiriöiden hoitoon.

La première phase pour la fibrose réparatrice après un infarctus du myocarde (IM) est la réponse inflammatoire. Sans inflammation, la cicatrisation est perturbée ce qui provoquerait la rupture du myocarde. Une forte réponse inflammatoire peut mener à une rupture en raison d’une dégradation excessive de la matrice extracellulaire. Afin d’améliorer le pronostic des patients, des techniques pour contrôler la réponse inflammatoire sont recherchées. En réponse au stress, MK2 (MAP kinase-activated protein kinase-2) est activée par p38α et β. Cette kinase régule l’inflammation en stabilisant l’ARNm de cytokines. Les souris où MK2 est inactivée (MK2-/-) présentent une diminution de l’expression des cytokines après l’injection de lipopolysaccharides. L’objectif de l’étude était de déterminer si l’absence de MK2 altérerait l’inflammation post-IM provoqué par la ligature permanente de l’artère interventriculaire antérieure chez des souris mâles MK2+/+ et MK2-/-. Cette étude démontre une réduction significative de mortalité chez les souris MK2-/-. Les échocardiographies ont révélé une altération similaire des fonctions cardiaques chez les souris MK2+/+ et MK2-/-, mais la structure était moins affectée chez les souris MK2-/-. La coloration au trichrome de Masson n’a démontré aucune différence pour la taille de la cicatrice ou la quantité de collagène. Aucune différence n’a été remarquée dans le recrutement des leucocytes. L’utilisation d’un RT2 Profiler PCR Array spécifique aux cytokines a démontré que l’abondance d’ARNm tend à être réduite dans les tissus sains MK2-/-, mais l’inflammation n’était pas réduite comparativement aux souris MK2+/+. En conclusion, MK2 ne semble pas essentielle à la réponse inflammatoire post-IM dans le coeur des souris. / The first phase of reparative fibrosis following a myocardial infarct (MI) is an inflammatory response. Without inflammation, scar formation is impaired, which leads to heart rupture. A strong response can also lead to heart rupture due to excessive ECM degradation. Efficient ways of controlling inflammation are constantly being explored to improve the prognosis in patients. In response to cellular stress, MAP kinase-activated protein kinase-2 (MK2) is activated by p38α and β. This protein serine/threonine kinase mediates the inflammatory process by stabilising pro-inflammatory cytokine mRNA. MK2-deficent mice (MK2-/-) show an impaired expression of cytokines, such as IL-1β and IL-6, in response to lipopolysaccharide injection. The objective of this study was to determine if the absence of MK2 impaired the inflammatory phase following an MI induced by permanent ligation of the left anterior descending artery (LADL) in 12-week-old male MK2+/+ and MK2-/- litter mate mice. This study shows that mortality was significantly reduced in MK2-/- mice. Echocardiographic imaging showed that heart function was affected in similar ways in MK2+/+ and MK2-/- mice whereas heart structure was less affected MK2-/- mice. Masson's trichrome staining revealed no difference in scar size and collagen content. No differences were observed in neutrophil and macrophage recruitment. The use of a RT2 Profiler PCR Array specific to cytokines showed that mRNA fold expression appeared to be reduced in MK2-/- healthy tissues but that the inflammatory response was not impaired. In conclusion, MK2 was not essential for the inflammatory phase of post-MI wound repair in the male mouse heart.

En février, 2009 un rapport de PHRMA (Pharmaceutical Research and Manufacturers of America) confirmait que plus de 300 médicaments pour le traitement des maladies cardiaques étaient en phase d’essais cliniques ou en révision par les agences règlementaires. Malgré cette abondance de nouvelles thérapies cardiovasculaires, le nombre de nouveaux médicaments approuvés chaque année (toutes indications confondues) est en déclin avec seulement 17 et 24 nouveaux médicaments approuvés en 2007 et 2008, respectivement. Seulement 1 médicament sur 5000 sera approuvé après 10 à 15 ans de développement au coût moyen de 800 millions $. De nombreuses initiatives ont été lancées par les agences règlementaires afin d’augmenter le taux de succès lors du développement des nouveaux médicaments mais les résultats tardent. Cette stagnation est attribuée au manque d’efficacité du nouveau médicament dans bien des cas mais les évaluations d’innocuité remportent la palme des causes d’arrêt de développement. Primum non nocere, la maxime d’Hippocrate, père de la médecine, demeure d’actualité en développement préclinique et clinique des médicaments. Environ 3% des médicaments approuvés au cours des 20 dernières années ont, par la suite, été retirés du marché suite à l’identification d’effets adverses. Les effets adverses cardiovasculaires représentent la plus fréquente cause d’arrêt de développement ou de retrait de médicament (27%) suivi par les effets sur le système nerveux. Après avoir défini le contexte des évaluations de pharmacologie de sécurité et l’utilisation des bio-marqueurs, nous avons validé des modèles d’évaluation de l’innocuité des nouveaux médicaments sur les systèmes cardiovasculaires, respiratoires et nerveux. Évoluant parmi les contraintes et les défis des programmes de développements des médicaments, nous avons évalué l’efficacité et l’innocuité de l’oxytocine (OT), un peptide endogène à des fins thérapeutiques. L’OT, une hormone historiquement associée à la reproduction, a démontré la capacité d’induire la différentiation in vitro de lignées cellulaires (P19) mais aussi de cellules souches embryonnaires en cardiomyocytes battants. Ces observations nous ont amené à considérer l’utilisation de l’OT dans le traitement de l’infarctus du myocarde. Afin d’arriver à cet objectif ultime, nous avons d’abord évalué la pharmacocinétique de l’OT dans un modèle de rat anesthésié. Ces études ont mis en évidence des caractéristiques uniques de l’OT dont une courte demi-vie et un profil pharmacocinétique non-linéaire en relation avec la dose administrée. Ensuite, nous avons évalué les effets cardiovasculaires de l’OT sur des animaux sains de différentes espèces. En recherche préclinique, l’utilisation de plusieurs espèces ainsi que de différents états (conscients et anesthésiés) est reconnue comme étant une des meilleures approches afin d’accroître la valeur prédictive des résultats obtenus chez les animaux à la réponse chez l’humain. Des modèles de rats anesthésiés et éveillés, de chiens anesthésiés et éveillés et de singes éveillés avec suivi cardiovasculaire par télémétrie ont été utilisés. L’OT s’est avéré être un agent ayant d’importants effets hémodynamiques présentant une réponse variable selon l’état (anesthésié ou éveillé), la dose, le mode d’administration (bolus ou infusion) et l’espèce utilisée. Ces études nous ont permis d’établir les doses et régimes de traitement n’ayant pas d’effets cardiovasculaires adverses et pouvant être utilisées dans le cadre des études d’efficacité subséquentes. Un modèle porcin d’infarctus du myocarde avec reperfusion a été utilisé afin d’évaluer les effets de l’OT dans le traitement de l’infarctus du myocarde. Dans le cadre d’un projet pilote, l’infusion continue d’OT initiée immédiatement au moment de la reperfusion coronarienne a induit des effets cardiovasculaires adverses chez tous les animaux traités incluant une réduction de la fraction de raccourcissement ventriculaire gauche et une aggravation de la cardiomyopathie dilatée suite à l’infarctus. Considérant ces observations, l’approche thérapeutique fût révisée afin d’éviter le traitement pendant la période d’inflammation aigüe considérée maximale autour du 3ième jour suite à l’ischémie. Lorsqu’initié 8 jours après l’ischémie myocardique, l’infusion d’OT a engendré des effets adverses chez les animaux ayant des niveaux endogènes d’OT élevés. Par ailleurs, aucun effet adverse (amélioration non-significative) ne fût observé chez les animaux ayant un faible niveau endogène d’OT. Chez les animaux du groupe placebo, une tendance à observer une meilleure récupération chez ceux ayant des niveaux endogènes initiaux élevés fût notée. Bien que la taille de la zone ischémique à risque soit comparable à celle rencontrée chez les patients atteints d’infarctus, l’utilisation d’animaux juvéniles et l’absence de maladies coronariennes sont des limitations importantes du modèle porcin utilisé. Le potentiel de l’OT pour le traitement de l’infarctus du myocarde demeure mais nos résultats suggèrent qu’une administration systémique à titre de thérapie de remplacement de l’OT devrait être considérée en fonction du niveau endogène. De plus amples évaluations de la sécurité du traitement avec l’OT dans des modèles animaux d’infarctus du myocarde seront nécessaires avant de considérer l’utilisation d’OT dans une population de patients atteint d’un infarctus du myocarde. En contre partie, les niveaux endogènes d’OT pourraient posséder une valeur pronostique et des études cliniques à cet égard pourraient être d’intérêt. / In february 2009, a report from PHRMA (Pharmaceutical Research and Manufacturers of America) confirmed that more than 300 drugs for treatment of cardiovascular diseases were in clinical trials or under review by regulatory agencies. Despite the abundance of new cardiovascular therapies, the number of new drugs approved each year (all indications combined) is declining steadily with only 17 and 24 new drugs approved in 2007 and 2008, respectively. Only 1 drug out of 5000 candidates will be approved after 10 to 15 years of development with an average cost of $800 millions. Several initiatives have been launched by regulatory agencies to increase the success rate in drug development but results are still awaited. This stagnation is attributed to the lack of efficacy of several drug candidates but safety assessments are the leading cause of drug development discontinuation. Primum non nocere, the maxim from Hippocrate, father of medicine, remains of major relevance in preclinical and clinical drug development. Over the past 20 years, approximately 3% of approved drugs were subsequently withdrawn from the market due to adverse effects. Cardiovascular adverse effects represent the most frequent cause of drug development discontinuation or withdrawal (27%) followed by effects on the nervous system. After defining the context of safety pharmacology evaluations and the use of biomarkers in drug development, we validated safety pharmacology models to investigate drug-induced cardiovascular, respiratory and neurological effects. As we progressed within constraints and challenges of drug development, we evaluated the efficacy and safety of oxytocin, an endogenous peptide with therapeutic potential. Oxytocin (OT), a hormone historically associated with reproduction, demonstrated the ability to induce in vitro differentiation of cell lines (P19) but also embryonic stem cells into beating cardiomyocytes. These observations lead us to consider the use of OT as a treatment for myocardial infarct. To achieve this ultimate goal, we first evaluated the pharmacokinetic of OT in an anesthetized rat model. These investigations highlighted the unique characteristics of OT including a very short half-life and a non-linear pharmacokinetic profile in response to the dose. Cardiovascular effects of OT in healthy animals were then evaluated in various species. In preclinical research, the use of various animal species and state of consciousness (conscious or anesthetized) is recognized as one of the best strategies to increase the predictive value of results obtained in animals to the human response. Our initial investigations of OT treatment regimens used various animal models including conscious and anesthetized rats, anesthetized pigs, conscious dogs with indirect blood pressure monitoring and diuresis and conscious monkeys with cardiovascular telemetry monitoring. These studies confirmed OT to have significant hemodynamic effects with variable responses depending on the state of consciousness (conscious or anesthetized), the dose, the administration protocol (bolus or infusion) and the species that were used. These screening studies enabled selection of a treatment regimen and dose without adverse effects that could subsequently be tested in efficacy studies. A porcine myocardial infarct (MI) model with reperfusion was used to evaluate the effects of OT following myocardial ischemia. In a pilot project, continuous infusion of OT initiated immediately at coronary reperfusion induced cardiovascular adverse effects in all treated animals including a reduction of left ventricular fraction shortening and worsening of dilated cardiomyopathy which is typical following MI. Considering these observations, the therapeutic strategy was revised to avoid OT treatment during the inflammatory phase which was considered maximal around day 3 post-ischemia. When initiated 8 days after MI, OT infusion induced adverse effects in animals with elevated endogenous levels of OT. In contrast, no significant effects (not statistically significant improvement) were observed in animals with low endogenous OT baseline. In placebo treated animals, a trend to observe a better recovery was noted in animals with high endogenous OT baseline. While the size of the ischemic zone was comparable to human patients with MI, the use of juvenile animals and the absence of coronary disease are important limitations of the porcine model. The potential of OT for treatment of MI remains but our results suggest that systemic administration of OT by continuous infusion as part of a replacement therapy should be investigated further in relation to endogenous levels. Further investigations on safety of the treatment with OT on animal MI models are warranted before the use of OT can be considered in the patient population after myocardial infarct. On the other hand, endogenous levels of OT may have a prognostic value and clinical trials to investigate this hypothesis may be of interest.

Introdução: Glicemia de jejum alterada tem sido associada a maior risco de desenvolver diabetes, comparando a indivíduos normoglicêmicos. Apesar de diabetes ser relacionado a aterosclerose e a piores desfechos cardiovasculares, os dados de literatura relacionando glicemia de jejum alterada à doença aterosclerótica são conflitantes. Os objetivos deste trabalho foram determinar (a) a incidência de diabetes em indivíduos com glicemia de jejum normal ou alterada em 1998 após um seguimento de até 12 anos; (b) se a glicemia de jejum alterada em 1998 e/ou diabetes incidente estiveram associados com aterosclerose subclínica no Estudo Longitudinal da Saúde do Adulto (ELSA-Brasil) ou à variável combinada de eventos clínicos não-fatais e escore de cálcio coronariano maior ou igual a 400. Métodos: Avaliamos 1.536 trabalhadores da Universidade de São Paulo, que participaram de um programa de avaliação em 1998 (idade 23-63 anos) e da linha de base do ELSA-Brasil (2008-2010). Apresentamos as taxas de incidência de diabetes brutas e ajustadas para todos os indivíduos e também estratificados por gênero e por índice de massa corpórea (IMC) em 1998. Utilizamos modelos de regressão brutos e ajustados para estimar a associação entre glicemia de jejum alterada em 1998 ou diabetes incidente com a espessura de íntima-média de carótidas (EIMC), escore de cálcio coronariano (CACS, do inglês Coronary Artery Calcium Score) e a variável composta CACS >= 400 ou eventos cardiovasculares incidentes (infarto do miocárdio ou revascularização). Resultados: Encontramos diabetes incidente em 177 indivíduos. A incidência de diabetes em nossa amostra foi de 9,8/1.000 pessoas-ano (Intervalo de confiança de 95% [IC95%]: 7,7-13,6). A incidência foi mais elevada entre os homens (11,2/1.000 pessoas-ano, IC95%: 8,6-15,0) do que entre as mulheres (8,5/1.000 pessoas-ano, IC95%: 5,3-15,3). Glicemia de jejum alterada em 1998 mostrou associação com maior risco de progressão para diabetes ao longo do seguimento (hazard ratio [HR]: 3,17; IC95%: 2,14-4,68) e HR: 7,42; IC95%: 4,75-11,57 para glicemias de jejum entre 100 e 109mg/dl e entre 110 e 125mg/dl, respectivamente). Glicemias entre 110 e 125mg/dl em 1998 foram associadas a maiores valores de EIMC (beta=+0,028; IC95%: 0,003 a 0,053) na linha de base do ELSA-Brasil. Ao excluir da análise aqueles com diabetes incidente, houve associação limítrofe, não-significativa, entre maiores valores de EIMC e glicemia de jejum entre 110 e 125mg/dl em 1998 (?=0,030; IC95%: -0,005 a 0,065). Ambos os níveis de glicemia de jejum alterada em 1998 não se mostraram associados ao CACS ou à variável composta de CACS >= 400 ou eventos cardiovasculares incidentes nos modelos de ajuste completo. Diabetes incidente foi associado a maiores valores de EIMC (em milímetros) (?=0,034; IC95%: 0,015 a 0,053), a CACS >= 400 (Razão de chances=2,84; IC95%: 1,17-6,91) e ao desfecho combinado de CACS >= 400 ou eventos cardiovasculares incidentes (Razão de chances=3,50; IC95%: 1,60-7,65). Conclusões: Glicemia de jejum alterada em 1998, especialmente nos valores mais próximos dos limiares de corte para diabetes, foram associados a maior incidência de diabetes ao longo do seguimento e a maiores valores de EIMC quando da avaliação inicial do ELSA-Brasil. Diabetes incidente entre as avaliações foi associado a maior risco cardiovascular / Introduction: Impaired fasting glucose has been associated with higher risk of incident diabetes, compared to normoglycemic individuals. Although diabetes mellitus is related to atherosclerosis and higher long-term cardiovascular burden, there are conflicting data about the association between impaired fasting glucose and atherosclerotic disease. We aimed (a) to determine diabetes incidence rates in individuals with normal or impaired fasting glucose in 1998 after follow-up of up to 12 years, (b) whether impaired fasting glucose in 1998 and/or incident diabetes were associated with subclinical atherosclerosis in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) or the combined variable of non-fatal clinical events or a coronary calcium score >= 400. Methods: We evaluated 1,536 civil servants from the University of São Paulo, who participated in both 1998 (aged 23-63 years) and ELSA-Brasil baseline (2008-2010) assessments and had complete data. We presented crude and adjusted diabetes incident rates for all individuals and then stratified by sex and body mass index (BMI) in 1998. We used crude and adjusted regression models to estimate the association between impaired fasting glucose in 1998 or incident diabetes and coronary intima-media thickness (CIMT), coronary artery calcium score (CACS) and the composite variable of a CACS?400 or incident cardiovascular events (myocardial infarction or revascularization). Results: We found incident diabetes in 177 individuals. Diabetes incidence in our sample was 9.8/1,000 person-years (95% confidence interval [95%CI]:7.7-13.6). Diabetes incidence was higher in men (11.2/1,000 person-years, 95%CI: 8.6-15.0) than women (8.5/1,000 person-years, 95%CI: 5.3 to 15.3). Impaired fasting glucose in 1998 was associated with a higher risk of progression to diabetes during follow-up (hazard ratio [HR]: 3.17; 95%CI: 2.14-4.68 and HR: 7.42; 95%CI: 4.75-11.57 for a fasting plasma glucose between 100 to 109mg/dl and 110 to 125 mg/dl, respectively). Fasting plasma glucose levels between 110 to 125 mg/dl in 1998 were associated with higher CIMT (beta=+0.028; 95%CI: 0.003 to 0.053) in ELSA-Brasil baseline. Excluding those with incident diabetes, there was a non-significant borderline association between higher CIMT (in mm) and fasting plasma glucose 110 to 125mg/dl (beta=0.030; 95%CI: -0.005 to 0.065). Fasting plasma glucose levels in 1998 were not associated with CACS or the composite variable of a CACS ? 400 or incident cardiovascular events in full-adjusted models. Incident diabetes was associated with higher CIMT (in mm) (beta=0.034; 95%CI: 0.015 to 0.053), CACS >= 400 (OR=2.84; 95%CI: 1.17-6.91) and the combined outcome of a CACS >= 400 or incident cardiovascular event (OR=3.50; 95%CI: 1.60-7.65). Conclusions: Elevated fasting plasma glucose in 1998, especially those near diabetes diagnosis limits were associated with higher diabetes incidence during follow-up and higher CIMT in ELSA-Brasil baseline assessment. Incident diabetes between assessments was associated with higher cardiovascular burden

En février, 2009 un rapport de PHRMA (Pharmaceutical Research and Manufacturers of America) confirmait que plus de 300 médicaments pour le traitement des maladies cardiaques étaient en phase d’essais cliniques ou en révision par les agences règlementaires. Malgré cette abondance de nouvelles thérapies cardiovasculaires, le nombre de nouveaux médicaments approuvés chaque année (toutes indications confondues) est en déclin avec seulement 17 et 24 nouveaux médicaments approuvés en 2007 et 2008, respectivement. Seulement 1 médicament sur 5000 sera approuvé après 10 à 15 ans de développement au coût moyen de 800 millions $. De nombreuses initiatives ont été lancées par les agences règlementaires afin d’augmenter le taux de succès lors du développement des nouveaux médicaments mais les résultats tardent. Cette stagnation est attribuée au manque d’efficacité du nouveau médicament dans bien des cas mais les évaluations d’innocuité remportent la palme des causes d’arrêt de développement. Primum non nocere, la maxime d’Hippocrate, père de la médecine, demeure d’actualité en développement préclinique et clinique des médicaments. Environ 3% des médicaments approuvés au cours des 20 dernières années ont, par la suite, été retirés du marché suite à l’identification d’effets adverses. Les effets adverses cardiovasculaires représentent la plus fréquente cause d’arrêt de développement ou de retrait de médicament (27%) suivi par les effets sur le système nerveux. Après avoir défini le contexte des évaluations de pharmacologie de sécurité et l’utilisation des bio-marqueurs, nous avons validé des modèles d’évaluation de l’innocuité des nouveaux médicaments sur les systèmes cardiovasculaires, respiratoires et nerveux. Évoluant parmi les contraintes et les défis des programmes de développements des médicaments, nous avons évalué l’efficacité et l’innocuité de l’oxytocine (OT), un peptide endogène à des fins thérapeutiques. L’OT, une hormone historiquement associée à la reproduction, a démontré la capacité d’induire la différentiation in vitro de lignées cellulaires (P19) mais aussi de cellules souches embryonnaires en cardiomyocytes battants. Ces observations nous ont amené à considérer l’utilisation de l’OT dans le traitement de l’infarctus du myocarde. Afin d’arriver à cet objectif ultime, nous avons d’abord évalué la pharmacocinétique de l’OT dans un modèle de rat anesthésié. Ces études ont mis en évidence des caractéristiques uniques de l’OT dont une courte demi-vie et un profil pharmacocinétique non-linéaire en relation avec la dose administrée. Ensuite, nous avons évalué les effets cardiovasculaires de l’OT sur des animaux sains de différentes espèces. En recherche préclinique, l’utilisation de plusieurs espèces ainsi que de différents états (conscients et anesthésiés) est reconnue comme étant une des meilleures approches afin d’accroître la valeur prédictive des résultats obtenus chez les animaux à la réponse chez l’humain. Des modèles de rats anesthésiés et éveillés, de chiens anesthésiés et éveillés et de singes éveillés avec suivi cardiovasculaire par télémétrie ont été utilisés. L’OT s’est avéré être un agent ayant d’importants effets hémodynamiques présentant une réponse variable selon l’état (anesthésié ou éveillé), la dose, le mode d’administration (bolus ou infusion) et l’espèce utilisée. Ces études nous ont permis d’établir les doses et régimes de traitement n’ayant pas d’effets cardiovasculaires adverses et pouvant être utilisées dans le cadre des études d’efficacité subséquentes. Un modèle porcin d’infarctus du myocarde avec reperfusion a été utilisé afin d’évaluer les effets de l’OT dans le traitement de l’infarctus du myocarde. Dans le cadre d’un projet pilote, l’infusion continue d’OT initiée immédiatement au moment de la reperfusion coronarienne a induit des effets cardiovasculaires adverses chez tous les animaux traités incluant une réduction de la fraction de raccourcissement ventriculaire gauche et une aggravation de la cardiomyopathie dilatée suite à l’infarctus. Considérant ces observations, l’approche thérapeutique fût révisée afin d’éviter le traitement pendant la période d’inflammation aigüe considérée maximale autour du 3ième jour suite à l’ischémie. Lorsqu’initié 8 jours après l’ischémie myocardique, l’infusion d’OT a engendré des effets adverses chez les animaux ayant des niveaux endogènes d’OT élevés. Par ailleurs, aucun effet adverse (amélioration non-significative) ne fût observé chez les animaux ayant un faible niveau endogène d’OT. Chez les animaux du groupe placebo, une tendance à observer une meilleure récupération chez ceux ayant des niveaux endogènes initiaux élevés fût notée. Bien que la taille de la zone ischémique à risque soit comparable à celle rencontrée chez les patients atteints d’infarctus, l’utilisation d’animaux juvéniles et l’absence de maladies coronariennes sont des limitations importantes du modèle porcin utilisé. Le potentiel de l’OT pour le traitement de l’infarctus du myocarde demeure mais nos résultats suggèrent qu’une administration systémique à titre de thérapie de remplacement de l’OT devrait être considérée en fonction du niveau endogène. De plus amples évaluations de la sécurité du traitement avec l’OT dans des modèles animaux d’infarctus du myocarde seront nécessaires avant de considérer l’utilisation d’OT dans une population de patients atteint d’un infarctus du myocarde. En contre partie, les niveaux endogènes d’OT pourraient posséder une valeur pronostique et des études cliniques à cet égard pourraient être d’intérêt. / In february 2009, a report from PHRMA (Pharmaceutical Research and Manufacturers of America) confirmed that more than 300 drugs for treatment of cardiovascular diseases were in clinical trials or under review by regulatory agencies. Despite the abundance of new cardiovascular therapies, the number of new drugs approved each year (all indications combined) is declining steadily with only 17 and 24 new drugs approved in 2007 and 2008, respectively. Only 1 drug out of 5000 candidates will be approved after 10 to 15 years of development with an average cost of $800 millions. Several initiatives have been launched by regulatory agencies to increase the success rate in drug development but results are still awaited. This stagnation is attributed to the lack of efficacy of several drug candidates but safety assessments are the leading cause of drug development discontinuation. Primum non nocere, the maxim from Hippocrate, father of medicine, remains of major relevance in preclinical and clinical drug development. Over the past 20 years, approximately 3% of approved drugs were subsequently withdrawn from the market due to adverse effects. Cardiovascular adverse effects represent the most frequent cause of drug development discontinuation or withdrawal (27%) followed by effects on the nervous system. After defining the context of safety pharmacology evaluations and the use of biomarkers in drug development, we validated safety pharmacology models to investigate drug-induced cardiovascular, respiratory and neurological effects. As we progressed within constraints and challenges of drug development, we evaluated the efficacy and safety of oxytocin, an endogenous peptide with therapeutic potential. Oxytocin (OT), a hormone historically associated with reproduction, demonstrated the ability to induce in vitro differentiation of cell lines (P19) but also embryonic stem cells into beating cardiomyocytes. These observations lead us to consider the use of OT as a treatment for myocardial infarct. To achieve this ultimate goal, we first evaluated the pharmacokinetic of OT in an anesthetized rat model. These investigations highlighted the unique characteristics of OT including a very short half-life and a non-linear pharmacokinetic profile in response to the dose. Cardiovascular effects of OT in healthy animals were then evaluated in various species. In preclinical research, the use of various animal species and state of consciousness (conscious or anesthetized) is recognized as one of the best strategies to increase the predictive value of results obtained in animals to the human response. Our initial investigations of OT treatment regimens used various animal models including conscious and anesthetized rats, anesthetized pigs, conscious dogs with indirect blood pressure monitoring and diuresis and conscious monkeys with cardiovascular telemetry monitoring. These studies confirmed OT to have significant hemodynamic effects with variable responses depending on the state of consciousness (conscious or anesthetized), the dose, the administration protocol (bolus or infusion) and the species that were used. These screening studies enabled selection of a treatment regimen and dose without adverse effects that could subsequently be tested in efficacy studies. A porcine myocardial infarct (MI) model with reperfusion was used to evaluate the effects of OT following myocardial ischemia. In a pilot project, continuous infusion of OT initiated immediately at coronary reperfusion induced cardiovascular adverse effects in all treated animals including a reduction of left ventricular fraction shortening and worsening of dilated cardiomyopathy which is typical following MI. Considering these observations, the therapeutic strategy was revised to avoid OT treatment during the inflammatory phase which was considered maximal around day 3 post-ischemia. When initiated 8 days after MI, OT infusion induced adverse effects in animals with elevated endogenous levels of OT. In contrast, no significant effects (not statistically significant improvement) were observed in animals with low endogenous OT baseline. In placebo treated animals, a trend to observe a better recovery was noted in animals with high endogenous OT baseline. While the size of the ischemic zone was comparable to human patients with MI, the use of juvenile animals and the absence of coronary disease are important limitations of the porcine model. The potential of OT for treatment of MI remains but our results suggest that systemic administration of OT by continuous infusion as part of a replacement therapy should be investigated further in relation to endogenous levels. Further investigations on safety of the treatment with OT on animal MI models are warranted before the use of OT can be considered in the patient population after myocardial infarct. On the other hand, endogenous levels of OT may have a prognostic value and clinical trials to investigate this hypothesis may be of interest.

Introdução: Glicemia de jejum alterada tem sido associada a maior risco de desenvolver diabetes, comparando a indivíduos normoglicêmicos. Apesar de diabetes ser relacionado a aterosclerose e a piores desfechos cardiovasculares, os dados de literatura relacionando glicemia de jejum alterada à doença aterosclerótica são conflitantes. Os objetivos deste trabalho foram determinar (a) a incidência de diabetes em indivíduos com glicemia de jejum normal ou alterada em 1998 após um seguimento de até 12 anos; (b) se a glicemia de jejum alterada em 1998 e/ou diabetes incidente estiveram associados com aterosclerose subclínica no Estudo Longitudinal da Saúde do Adulto (ELSA-Brasil) ou à variável combinada de eventos clínicos não-fatais e escore de cálcio coronariano maior ou igual a 400. Métodos: Avaliamos 1.536 trabalhadores da Universidade de São Paulo, que participaram de um programa de avaliação em 1998 (idade 23-63 anos) e da linha de base do ELSA-Brasil (2008-2010). Apresentamos as taxas de incidência de diabetes brutas e ajustadas para todos os indivíduos e também estratificados por gênero e por índice de massa corpórea (IMC) em 1998. Utilizamos modelos de regressão brutos e ajustados para estimar a associação entre glicemia de jejum alterada em 1998 ou diabetes incidente com a espessura de íntima-média de carótidas (EIMC), escore de cálcio coronariano (CACS, do inglês Coronary Artery Calcium Score) e a variável composta CACS >= 400 ou eventos cardiovasculares incidentes (infarto do miocárdio ou revascularização). Resultados: Encontramos diabetes incidente em 177 indivíduos. A incidência de diabetes em nossa amostra foi de 9,8/1.000 pessoas-ano (Intervalo de confiança de 95% [IC95%]: 7,7-13,6). A incidência foi mais elevada entre os homens (11,2/1.000 pessoas-ano, IC95%: 8,6-15,0) do que entre as mulheres (8,5/1.000 pessoas-ano, IC95%: 5,3-15,3). Glicemia de jejum alterada em 1998 mostrou associação com maior risco de progressão para diabetes ao longo do seguimento (hazard ratio [HR]: 3,17; IC95%: 2,14-4,68) e HR: 7,42; IC95%: 4,75-11,57 para glicemias de jejum entre 100 e 109mg/dl e entre 110 e 125mg/dl, respectivamente). Glicemias entre 110 e 125mg/dl em 1998 foram associadas a maiores valores de EIMC (beta=+0,028; IC95%: 0,003 a 0,053) na linha de base do ELSA-Brasil. Ao excluir da análise aqueles com diabetes incidente, houve associação limítrofe, não-significativa, entre maiores valores de EIMC e glicemia de jejum entre 110 e 125mg/dl em 1998 (?=0,030; IC95%: -0,005 a 0,065). Ambos os níveis de glicemia de jejum alterada em 1998 não se mostraram associados ao CACS ou à variável composta de CACS >= 400 ou eventos cardiovasculares incidentes nos modelos de ajuste completo. Diabetes incidente foi associado a maiores valores de EIMC (em milímetros) (?=0,034; IC95%: 0,015 a 0,053), a CACS >= 400 (Razão de chances=2,84; IC95%: 1,17-6,91) e ao desfecho combinado de CACS >= 400 ou eventos cardiovasculares incidentes (Razão de chances=3,50; IC95%: 1,60-7,65). Conclusões: Glicemia de jejum alterada em 1998, especialmente nos valores mais próximos dos limiares de corte para diabetes, foram associados a maior incidência de diabetes ao longo do seguimento e a maiores valores de EIMC quando da avaliação inicial do ELSA-Brasil. Diabetes incidente entre as avaliações foi associado a maior risco cardiovascular / Introduction: Impaired fasting glucose has been associated with higher risk of incident diabetes, compared to normoglycemic individuals. Although diabetes mellitus is related to atherosclerosis and higher long-term cardiovascular burden, there are conflicting data about the association between impaired fasting glucose and atherosclerotic disease. We aimed (a) to determine diabetes incidence rates in individuals with normal or impaired fasting glucose in 1998 after follow-up of up to 12 years, (b) whether impaired fasting glucose in 1998 and/or incident diabetes were associated with subclinical atherosclerosis in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) or the combined variable of non-fatal clinical events or a coronary calcium score >= 400. Methods: We evaluated 1,536 civil servants from the University of São Paulo, who participated in both 1998 (aged 23-63 years) and ELSA-Brasil baseline (2008-2010) assessments and had complete data. We presented crude and adjusted diabetes incident rates for all individuals and then stratified by sex and body mass index (BMI) in 1998. We used crude and adjusted regression models to estimate the association between impaired fasting glucose in 1998 or incident diabetes and coronary intima-media thickness (CIMT), coronary artery calcium score (CACS) and the composite variable of a CACS?400 or incident cardiovascular events (myocardial infarction or revascularization). Results: We found incident diabetes in 177 individuals. Diabetes incidence in our sample was 9.8/1,000 person-years (95% confidence interval [95%CI]:7.7-13.6). Diabetes incidence was higher in men (11.2/1,000 person-years, 95%CI: 8.6-15.0) than women (8.5/1,000 person-years, 95%CI: 5.3 to 15.3). Impaired fasting glucose in 1998 was associated with a higher risk of progression to diabetes during follow-up (hazard ratio [HR]: 3.17; 95%CI: 2.14-4.68 and HR: 7.42; 95%CI: 4.75-11.57 for a fasting plasma glucose between 100 to 109mg/dl and 110 to 125 mg/dl, respectively). Fasting plasma glucose levels between 110 to 125 mg/dl in 1998 were associated with higher CIMT (beta=+0.028; 95%CI: 0.003 to 0.053) in ELSA-Brasil baseline. Excluding those with incident diabetes, there was a non-significant borderline association between higher CIMT (in mm) and fasting plasma glucose 110 to 125mg/dl (beta=0.030; 95%CI: -0.005 to 0.065). Fasting plasma glucose levels in 1998 were not associated with CACS or the composite variable of a CACS ? 400 or incident cardiovascular events in full-adjusted models. Incident diabetes was associated with higher CIMT (in mm) (beta=0.034; 95%CI: 0.015 to 0.053), CACS >= 400 (OR=2.84; 95%CI: 1.17-6.91) and the combined outcome of a CACS >= 400 or incident cardiovascular event (OR=3.50; 95%CI: 1.60-7.65). Conclusions: Elevated fasting plasma glucose in 1998, especially those near diabetes diagnosis limits were associated with higher diabetes incidence during follow-up and higher CIMT in ELSA-Brasil baseline assessment. Incident diabetes between assessments was associated with higher cardiovascular burden