FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O acidente vascular cerebral (AVE) à uma das principais causa de mortalidade no Brasil, acometendo cerca de 200.000 indivÃduos anualmente. A fisiopatologia do AVE isquÃmico envolve uma complexa cascata de eventos como a inflamaÃÃo e o estresse oxidativo que podem à morte neuronal e dÃficits cognitivos. O α-bisabolol à um Ãlcool sesquiterpeno, monocÃclico, que ocorre na natureza e à encontrado como constituinte majoritÃrio do Ãleo essencial sintÃtico da Matricaria chamomilla, que possui atividade antiinflamatÃria, antioxidante e anti-apoptÃtica jà descritas. Para avaliar o efeito neuroprotetor deste composto em camundongos submetidos à oclusÃo permanente da artÃria cerebral media (pMCAO), os animais foram prà e pÃs tratados com α-bisabolol nas doses de 50, 100 e 200 mg/kg, v.o, durante 24, 48, 72, 96 ou 120 horas apÃs a isquemia. Os animais foram avaliados 24h apÃs a isquÃmia para verificar a Ãrea de lesÃo isquÃmica, avaliaÃÃo neurolÃgica e atividade da mieloperoxidase. 72 horas apÃs a pMCAO, os testes de atividade locomotora, memÃria de trabalho e memÃria aversiva recente foram realizados. 96 horas apÃs a pMCAO foi realizado o teste do reconhecimento de objecto, e os animais foram eutanasiados para a realizaÃÃo da Imunohistoquimica para TNF-α, iNOS e GFAP e anÃlise histologica para Cresil violeta e Fluoro Jade C. Finalmente, 120h apÃs a isquemia, avaliou-se a memÃria espacial. O α-bisabolol reduziu significativamente a lesÃo isquemica e o dÃficit neurolÃgico e normalizou a atividade locomotora. O α-bisabolol mostrou proteÃÃo contra os dÃficits nas memÃrias de trabalho, espacial, reconhecimento de objeto e aversiva. O α-bisabolol (200 mg/kg) preveniu significativamente o aumento da MPO e TNF-α no cÃrtex temporal e o aumento do iNOS tanto no cÃrtex temporal como no estriado. Tambem preveniu o aumento da astrogliose nessas Ãreas. O α-bisabolol (200 mg/kg) mostrou protecÃÃo contra a morte neuronal. Os resultados do presente estudo mostraram que o α-bisabolol possui atividade neuroprotetora provavelmente devido a sua aÃÃo antiinflamatÃria, mas outros mecanismos nÃo podem ser descartados. / Stroke is the leading cause of mortality in Brazil, affecting about 200,000 individuals annually. The pathophysiology of ischemic stroke involves a complex cascade of events such as inflammation and oxidative stress which will lead to neuronal death and cognitive deficits. The α-bisabolol is a sesquiterpene alcohol, natural, monocyclic, found as main constituents of the essential oil of Matricaria chamomilla, which has anti-inflammatory, antioxidant and anti-apoptotic already described. To evaluate the neuroprotective effects of this compound in mice underwent permanent occlusion of the middle cerebral artery (pMCAO), the animals were pre and post treated with α-bisabolol at doses of 50, 100 and 200 mg / kg, orally for 24, 48, 72, 96 or 120 hours after pMCAO. The animals were evaluated 24 hours after ischemia to verify the area of ischemic damage, and neurological evaluation and myeloperoxidase activity. Seventy-two hours after pMCAO, the locomotor activity tests, working memory and aversive recent memory were performed. Ninety six hours after the pMCAO was performed the object recognition test, and the animals were euthanized for carrying out the immunohistochemistry for TNF-α, iNOS and GFAP and for histology analyes Cresil violet and Fluoro Jade C. Finally, 120 h after pMCAO, the spatial memory was evaluated. The α-bisabolol reduced significantly ischemic damage and neurological deficit and normalized the locomotor activity. The α-bisabolol showed protection against the deficits in working, spatial, object recognition and aversive memories. The α-bisabolol (200 mg / kg) significantly prevented the increase of MPO and TNF-α in the temporal cortex and the increased of iNOS both in the temporal cortex and in striatum. Also prevented the increase in astrogliosis in there area. The α-bisabolol (200 mg / kg) showed protection against neuronal death. The results of this study showed that α-bisabolol has neuroprotective activity probably due to its anti-inflammatory action, but other mechanisms can not be discarded.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Investigar os efeitos da ornitina &#945;-cetoglutarato (OKG) no sangue e mÃsculo gastrocnÃmio de ratos submetidos à isquemia-reperfusÃo do membro pÃlvico. MÃtodo - Quarenta e dois ratos foram distribuÃdos aleatoriamente em trÃs grupos: Sham (S), Isquemia (I) e Isquemia-reperfusÃo (R). Estes grupos foram distribuÃdos em subgrupos de acordo com o tempo e com o composto utilizado na gavagem. Todos os animais receberam gavagem de caseinato de cÃlcio ou OKG em dose Ãnica, noventa minutos antes da primeira laparotomia exploradora (LE). Os subgrupos S receberam apenas caseinato, os subgrupos I e R receberam caseinato ou OKG na mesma dose, de 5g/kg de peso. As amostras foram colhidas em trÃs momentos: imediatamente apÃs a LE; apÃs 6h da LE com isquemia (6h de isquemia) e sem isquemia e apÃs 6,5h da LE com isquemia-reperfusÃo (0,5h de reperfusÃo) e sem isquemia-reperfusÃo. Para anÃlise dos resultados foram utilizados: mÃdia, desvio padrÃo e teste de normalidade de Korogorov-Smirnov. Caso os resultados fossem normalizÃveis, aplicou-se o teste ANOVA para avaliaÃÃo de diferenÃa significante, no caso dos resultados nÃo serem normalizÃveis utilizou-se o teste de Kurskal-Wallis com o mesmo fim. Em todos os testes fixou-se em 0,05 ou 5%, a significÃncia estatÃstica. Resultados - No grupo S, nos metabÃlitos plasmÃticos, apÃs 6h e 6,5h da LE, quando comparados ao momento da LE (0h), houve aumento de: CPK 6h [141,83  47,88 versus 67,17  21,58 â p<0,004], CPK 6,5h [180,67  70,19 versus 67,17  21,58 â p<0,001]; LDH 6h [248,96  80,62 versus 74,40  33,84 â p<0,001]. Nos metabÃlitos musculares houve aumento de: lactato 6,5h [ 3,52  1,27 versus 1,57  0,76 â p<0,008]. Houve reduÃÃo de: piruvato 6h [0,035  0,024 versus 0,087  0,041 â p<0,004]. No grupo I foram observadas, para o subgrupo submetido à isquemia + caseinato em relaÃÃo ao sham, no plasma, elevaÃÃes em: CPK [635,17  231,71 versus 141,83  47,88 â p<0,001], LDH [551,16  142,63 versus 248,96  80,62 â p<0,002], piruvato [0,390  0,069 versus 0,061  0,045 â p<0,001]. No mÃsculo houve elevaÃÃo de: piruvato [0,127  0,044 versus 0,035  0,024 â p<0,002], lactato [8,158  0,717 versus 2,737  0,499 â p<0,001] e TBARS [0,012  0,004 versus 0,002  0,001 â p<0,001. Neste mesmo grupo comparando-se o subgrupo isquemia + OKG ao subgrupo sham encontrou-se, no plasma, elevaÃÃo em: CPK [868,17  308,30 versus 141,83  47,88 â p<0,001], glutationa [19,545  2,088 versus 6,432  1,062 â p<0,001] e no mÃsculo elevaÃÃo da glutationa [101,85  16,45 versus 14,73  0,87 p<0,001]. Ainda no grupo I, foi observado, para o subgrupo isquemia + OKG versus isquemia + caseinato, no plasma, queda em: LDH [296,26  93,62 versus 551,16  142,62 â p<0,004], glicose [104,16  20,81 versus 160,33  27,47 â p<0,001], piruvato [0,046  0,012 versus 0,390  0,069 â p<0,001], e elevaÃÃo de glutationa [19,54  2,08 versus 5,52  0,92 â p<0,001]. No mÃsculo foi evidenciada diminuiÃÃo do piruvato [0,047  0,031 versus 0,127  0,045 â p<0,004], lactato [2,47  0,74 versus 8,15  0,71 â p<0,001], TBARS [0,004  0,004 versus 0,012  0,004 â p<0,013] e elevaÃÃo glutationa [101,85  16,45 versus 14,44  2,09 â p<0,001]. No grupo R. foi observada, quando comparado o subgrupo reperfusÃo + caseinato ao Sham, no plasma, elevaÃÃo de: CPK [606,33  79,84 versus 180,66  70,19 â p<0,001], No mÃsculo elevaÃÃo do piruvato [0,065  0,027 versus 0,030  0,033 â p<0,047] e lactato [7,16  2,33 versus 3,52  1,27 â p<0,013] alÃm de queda na G6PDH [0,462Â0,22 versus 0,207Â0,22 p<0,04] . No grupo R quando comparado o subgrupo reperfusÃo + OKG ao subgrupo Sham, no plasma, foi evidenciado aumento em: CPK [558,00  102,83 versus 180,66  70,19 â p<0,001] e glicose [232,16  59,76 versus 118,16  24,22 â p<0,001]. No mÃsculo houve diminuiÃÃo de G6PDH [0,182Â0,22 versus 0,462Â0,22]. Ainda no grupo R quando comparado o subgrupo reperfusÃo + OKG ao reperfusÃo + caseinato, no plasma, houve elevaÃÃo da glicose [232,16  59,76 versus 158,00  24,20 â p<0,013]. No mÃsculo foi notada queda no lactato [3,63  1,16 versus 7,16  2,33 â p<0,008] e elevaÃÃo da glutationa [63,18  18,98 versus 16,17  1,96 â p<0,001]. ConclusÃes - O trauma cirÃrgico desencadeou alteraÃÃes significativas em alguns metabÃlitos estudados. O modelo de isquemia-reperfusÃo demonstrou efetividade. A OKG, em dose Ãnica por gavagem, demonstrou aÃÃes prÃ-glicolÃticas aerÃbica a nÃvel muscular e sistÃmico; proteÃÃo contra lesÃo da cÃlula muscular, e efeito antioxidante muscular e sistÃmico durante a lesÃo de isquemia quanto apÃs lesÃo de isquemia/reperfusÃo. / To investigate the effects of the ornitine &#945;-ketoglutarate (OKG) upon metabolites in vivo concentrations in whole blood and gastrocnemic muscle tissue of rats submitted to ischemia-reperfusion of the pelvic limb. Methods - Forty two rats were randomly distributed into three groups: Sham (S), Ischemia (I) and Ischemia-reperfusion (R). These groups were redistributed into subgroups, according to time and to the substance used in the gavage. All animals received via gavage calcium caseinate or OKG as a single dose, ninety minutes before the first laparotomy (L). The subgroup S received only caseinate, whereas subgroups I and R received caseinate or OKG, at the same dose of 5g/kg body weight. Samples were collected at three moments: immediately after L; after 6h with ischemia (ischemia of 6h) or without ischemia; and after 6,5h of L with ischemia-reperfusion (reperfusion of 0,5h) or without ischemia-reperfusion. Data expressed as: mean  standard deviation, normality test of Korogorov-Smirnov. In case of the results went normalized, the test ANOVA was applied for evaluation significant difference, in case of the results was not normalized, the test of Kurskal-Wallis was used. Significant variations were considered when p <0,05.Results - In S group, at the plasmatic samples, after six hours (6h) or six hours and thirty minutes (6,5h) of L, when compared versus at the moment of L (0h), there was increase of: CPK 6h [141,83  47,88 versus 67,17  21,58 - p <0,004], CPK 6,5h [180,67  70,19 versus 67,17  21,58 - p <0,001]; LDH 6h [248,96  80,62 versus 74,40  33,84 - p <0,001]. In muscular samples there was increase of: lactate 6,5h [3,52  1,27 versus 1,57  0,76 - p <0,008]; there were reductions of: pyruvate 6h [0,035  0,024 versus 0,087  0,041 - p <0,004]. In group I it was observed, for the subgroup submitted to ischemia + caseinate in relation to sham, in plasma, elevations of: CPK [635,17  231,71 versus 141,83  47,88 - p <0,001], DHL [551,16  142,63 versus 248,96  80,62 - p <0,002], pyruvate [0,390  0,069 versus 0,061  0,045 - p <0,001]. In muscle there were elevations of: pyruvate [0,127  0,044 versus 0,035  0,024 - p <0,002], lactate [8,15  0,71 versus 2,73  0,49 - p <0,001] and TBARS [0,012  0,004 versus 0,002  0,001 - p <0,001]. In this same group when comparing subgroup ischemia + OKG versus subgroup sham there were, in the plasma, elevations of: CPK [868,17  308,30 versus 141,83  47,88 - p <0,001], glutathione [19,54  2,08 versus 6,43  1,06 - p <0,001]. In muscle there was elevation of glutathione [101,851  16,457 versus 14,737  0,874 p <0,001]. Still in the I group, it was observed, when subgroup ischemia + OKG was compared to ischemia + caseinate, in the plasma, a decrease of: LDH [296,26  93,62 versus 551,16  142,62 - p <0,004], glucose [104,16  20,81 versus 160,33  27,47 - p <0,001], pyruvate [0,046  0,012 versus 0,390  0,069 - p <0,001] and an elevation of glutathione [19,54  2,08 versus 5,52  0,92 - p <0,001]. In muscle there were decreases of pyruvate [0,047  0,031 versus 0,127  0,045 - p <0,004], lactate [2,47  0,74 versus 8,15  0,71 - p <0,001], TBARS [0,004  0,004 versus 0,012  0,004 - p <0,013]. It was observed elevation of glutathione [101,85  16,45 versus 14,44  2,09 - p <0,001]. In R group, it was observed, when comparing subgroup reperfusion + caseinate versus sham at the plasma, elevations of: CPK [606,33  79,84 versus 180,66  70,19 - p <0,001]. In muscle it was observed elevations of lactate [7,16  2,33 versus 3,52  1,27 - p <0,013] and decrease of G6PDH [0,462Â0,22 versus 0,207Â0,22 p<0,04]. In R group, when comparing subgroup reperfusion + OKG to subgroup sham, at the plasma, it was evidenced increase of: CPK [558,00  102,83 versus 180,66  70,19 - p <0,001], glucose [232,16  59,76 versus 118,16  24,22 - p <0,001]. In muscle there was observed decrease of G6PDH [0,182Â0,22 versus 0,462Â0,22]. Still in the group R when comparing the subgroup reperfusion + OKG versus the subgroup reperfusion + caseinate, at the plasma, there were elevations of glucose [232,16  59,76 versus 158,00  24,20 - p <0,013]. In muscle it was noticed a decrease of lactate [3,63  1,16 versus 7,16  2,33 - p <0,008] and elevation of glutathione [63,18  18,98 versus 16,17  1,96 - p <0,001]. Conclusions - Surgical trauma promoted significant alterations in some studied samples. The ischemia-reperfusion model demonstrated to be effective. OKG, as a single dose for gavage demonstrated pro glycolytic aerobic effect. Muscular and systemic protection against muscle cell lesion was also observed as well as an antioxidant effect at the end of ischemia and after ischemia-reperfusion injury

Preeclampsia (PE) remains one of the most enigmatic and pervasive conditions developed during pregnancy and is a leading cause of maternal and fetal morbidity and mortality throughout the world. Afflicting nearly 5-8% of pregnancies in the Unites States, PE is most commonly characterized by an increase in blood pressure and high protein excretion near or after the 20th week of gestation. Unfortunately, few effective treatments are available, and the only "cure" is delivery. While the molecular pathogenesis of PE remains undefined, an interruption in placental blood flow, or placental ischemia, is widely observed as a primary contributor to the syndrome progression. Furthermore, to investigate the role of both pharmacological and non-pharmacological modalities to prevent placental ischemia induced hypertension, we employed a robust model of reduced utero-placental perfusion pressure (RUPP) in the pregnant rat. First, in Chapter IV, exercise initiated during gestation was not effective in the prevention of RUPP-induced hypertension, whereas exercise training prior to and continued through gestation prevented the increase in blood pressure. Though the molecular contributions to this effect are undefined, the effects appear to be independent of angiogenic balance restoration. Finally, in Chapter V, administration of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) was explored as a novel pharmacological modality to prevent the onset of hypertension and endothelial dysfunction in the RUPP model. As hypothesized, AICAR ameliorated the RUPP-induced hypertension, and the anti-hypertensive effect in the RUPP appears to be dependent on the restoration of angiogenic balance in the maternal plasma. This dissertation includes previously published and unpublished co-authored material.

Objetivo: Analisar e descrever o perfil de expressão das proteínas relacionadas ao mecanismo de apoptose (PARP e AIF), e o perfil de expressão gênica sérica do microRNA-9 relacionado ao mecanismo de apoptose, em ratos submetidos à isquemia cerebral focal por oclusão da ACM por 90 minutos, seguida de reperfusão de 48horas, associado ou não com modelo de alcoolismo crônico. Métodos: Foram utilizados 20 ratos Wistar adultos, subdivididos em 4 grupos experimentais: grupo controle (C): animais submetidos apenas à anestesia; grupo isquêmico (I): animais submetidos à isquemia cerebral focal por 90 minutos seguido por reperfusão de 48 horas; grupo alcoolizado (A): animais que receberam diariamente álcool etílico absoluto diluído a 20% em água durante quatro semanas; e, grupo isquêmico e alcoolizado (IA): animais submetidos ao mesmo tratamento do grupo A e que, após quatro semanas foram submetidos à isquemia cerebral focal durante 90 minutos, seguido por reperfusão de 48 horas. As amostras do encéfalo coletadas foram processadas para a análise imunohistoquímica (para a expressão protéica de PARP-1 e AIF); e o sangue da artéria ventral da cauda foi coletado para a análise da expressão gênica do miRNA-9, relacionada ao mecanismo de apoptose, pela técnica de PCR em tempo real. Resultados: A comparação entre os grupos identificou uma redução da expressão proteica de PARP-1 nos animais do grupo AI quando comparado com os demais. Foi observada marcação positiva nuclear para a proteína AIF somente no grupo IA. Não houve diferença estatisticamente significante da expressão sérica do miRNA-9 entre os grupos. Conclusão: O modelo proposto, pode não ter sido suficiente para promover a ativação de AIF nos grupos C, A e I e desta forma, a apoptose celular por essa via analisada. A expressão proteica de PARP-1 no grupo A, associado com a expressão nula de AIF, indica um efeito neuroprotetor do etanol neste grupo. A redução da expressão proteica de PARP-1 não afetou sua atividade enzimática, proporcionando, mesmo em baixas concentrações, ativação de AIF no grupo IA. A expressão de PARP- 1 no grupo I, associada a expressão nula de AIF indica que o modelo de isquemia possivelmente gerou leves danos no DNA o que estimulou a ativação de PARP-1 somente em níveis suficientes para promover a reparação do DNA e não a ativação do processo de apoptose pela translocação de AIF. A expressão gênica sérica do miRNA- 9 observada indicou que a mesma foi suprimida quando exposta a mecanismos de estresse (alcoolismo, isquemia e a associação dos mesmos). A correlação do miRNA-9 com a expressão proteica de PARP-1 e AIF, indicou um aspecto protetor da baixa regulação do miRNA-9 tanto em animais alcoolizados como em animais isquêmicos. O grupo IA apresentou uma tendência a baixa expressão do miRNA-9, baixa expressão de PARP-1 e alta expressão de AIF, indicando que a associação álcool e isquemia tenha interferido no efeito protetor do miRNA-9 visto nos demais grupos / Aim: To analyze and describe the expression profile of proteins related to apoptosis mechanism (PARP and AIF), and profile of gene expression of miRNA-9 related to apoptosis mechanism in rats submitted to focal cerebral ischemia by occlusion of the CMA for 90 minutes, followed by 48 hours of reperfusion, associated or without associated to chronic alcoholism model. Methods: 20 adult Wistar rats were used, divided into 4 groups: control group (C): animals submitted only to anesthesia; Ischemic group (I): animals subjected to focal cerebral ischemia for 90 minutes followed by 48 hours of reperfusion; alcoholic group (A): animals that received daily solution of 20% of absolute ethyl alcohol diluted in water during four weeks; and ischemic group and alcoholized (IA): Animals subjected to the same treatment group A and after four weeks were subjected to focal cerebral ischemia for 90 minutes followed by 48 hours of reperfusion. The brain samples were collected and processed for immunohistochemical analysis (for protein expression - PARP-1 and AIF); and the blood from ventral artery of tail was collected for the analysis, by PCR in real time, of gene expression of miRNA-9 related to the mechanism of apoptosis. Results: The comparison between the groups identified a decrease in protein expression (PARP-1) in animals from IA group compared to others groups. Nuclear positive staining was observed for the AIF protein only in the IA group. There was no significant difference in serum expression of miRNA-9 between the groups. Conclusion: The proposed model may not have been sufficient to promote the activation of AIF in groups C, A and I, and thus the apoptosis analyzed in this way. Protein expression of PARP-1 in group A associated with a null expression of AIF, indicate a neuroprotective effect of ethanol in this group. The reduction of protein expression PARP-1 did not affect its enzymatic activity, providing even at low concentrations, activation AIF in IA group. The expression of PARP-1 in group I associated with null expression of AIF showed that model of ischemia, possibly, promoted light damage in DNA which stimulated PARP-1 activation just in sufficient levels to promote DNA repair, and without activation of apoptosis by translocation of AIF. The gene expression of miRNA-9 indicated that it was suppressed when exposed to mechanical stress (alcoholism, ischemia and combination thereof). The correlation of miRNA-9 with the protein expression (PARP-1 and AIF), indicated a protective aspect of downregulation of the miRNA-9 in both animals drunk as ischemic animals. IA group showed a trend to low expression of miRNA-9 and PARP- 1, in other hand an overexpression of AIF, indicating that the association between alcohol and ischemia interfered in protective effect of miRNA-9 seen in the other groups

Release of glutamate in cerebral ischemia results in an excitotoxic reaction in the central nervous system resulting in neuronal cell loss. Providing neuronal protection via N‐methyl D‐asparate (NMDA) receptor blockade in response to cerebral ischemia may result in preservation of function following ischemia. The present study was designed to test compound AT010, an NMDA signaling antagonist, on behavioral compensation and infarct size in a cerebral ischemia model in the rat. Animals were surgically implanted with a filament via the external carotid artery, providing an occlusion of he medial cerebral artery for 60 min. Approximately 30‐45 minutes prior to surgery, the compound AT010 (3uM or 10uM) or saline was iv administered at 1% of body weight. All animals were behaviorally tested on behavioral tasks that analyzed postural reflex, limb placement, righting reflex, adhesive removal, and behavioral motor function at 3, 7, and 14 days post‐ischemia. In addition, animals were tested on the Morris water maze, a spatial memory task 28 days post‐ischemia. Regardless of dose, composite neurological scores for all motor and sensory tasks were higher for animals given AT010 compared to saline at 7 and 14 days post‐ ischemia. Water maze results revealed significant improvement of animals administered the higher dose of AT010 (10uM) on acquisition and probe trial performance, although no effect was revealed for the lower dose (3 uM). Finally, analysis of brain tissue samples revealed no significant effect on infarct size. These results indicate that compensation occurred throughout the undamaged brain areas, likely through synaptic communication changes as a result of drug treatment.

abstract: Stroke remains a leading cause of adult disability in the United States. In recent studies, chronic vagus nerve stimulation (VNS) has been proven to enhance functional recovery when paired with motor rehabilitation training after stroke. Other studies have also demonstrated that delivering VNS during the onset of a stroke may elicit some neuroprotective effects as observed in remaining neural tissue and motor function. While these studies have demonstrated the benefits of VNS as a treatment or therapy in combatting stroke damage, the mechanisms responsible for these effects are still not well understood or known. The aim of this research was to further investigate the mechanisms underlying the efficacy of acute VNS treatment of stroke by observing the effect of VNS when applied after the onset of stroke. Animals were randomly assigned to three groups: Stroke animals received cortical ischemia (ET-1 injection), VNS+Stroke animals received acute VNS starting within 48 hours after cortical ischemia and continuing once per day for three days, or Control animals which received neither the injury nor stimulation. Results showed that stroke animals receiving acute VNS had smaller lesion volumes and larger motor cortical maps than those in the Stroke group. The results suggest VNS may confer neuroprotective effects when delivered within the first 96 hours of stroke. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2019

Introduction: La lésion d'ischémie - reperfusion (I/R) intestinale est associée à une mortalité élevée.Le rôle de la transmigration des neutrophiles est probablement essentiel dans le dysfonctionnement de la barrière induit par la lésion I/R et la nécrose subséquente. Le but de notre étude était d'évaluer, au niveau pré-clinique, la valeur thérapeutique potentielle du peptide P8RI (un agoniste de CD31) dans la lésion I/R de l'intestine grêle.Méthodes: I/R intestinale a été induite chez des rats Wistar par clampage de l'artère mésentérique supérieure (AMS) pendant 30 min suivi par 4 h de reperfusion. Trois groupes de rats ont été comparés:P8RI (n = 20, I/R et P8RI 2,5 mg/kg/h de reperfusion), I/R témoins positifs (n = 21, I/R et infusion de sérum physiologique) et témoins (n = 14, dissection de l'AMS sans clampage et infusion de sérum physiologique). La matrix métallopeptidase 9 (MMP-9) dans la plasma, le liquide péritonéal et l'intestin; la MPO intestinale, l'ADN libre plasmatique, les taux d'hémoglobine intraluminale e tl'épaisseur épithéliale ont été évalués comme marqueurs intermédiaires de la lésion intestinale. La détection du matériel génétique d'E.coli par PCR quantitative dans le sang a été également réalisée chez les témoins positifs et chez les rats traités par P8RI pendant la période de reperfusion. Le CD31clivé dans le plasma a été mesuré par une méthode d'ELISA maison. Résultats: La grade histologique de l'intestin grêle chez les animaux traités par P8RI est supérieur àcelui des témoins positifs d'I/R (p < 0,05). P8RI protège l'intestin grêle contre la destruction épithéliale induite par lésion I/R (p < 0,01). Il y a une corrélation négative significative entre l'abrasion épithéliale et le score de Chiu de classement histologique de la lésion I/R mésentérique (r = -0,7245, p < 0.001).P8RI protège l'intestin grêle de la MPO in situ, de la libération de la MMP-9 (p < 0,05) et des complications hémorragiques digestives causées par lésion I/R (p < 0,01). Les taux plasmatiques et péritonéaux accrus de MMP-9, induits par I/R, sont significativement réduits par P8RI (p < 0,05 et p <0,01, respectivement). L'ADN d'E.coli circulant est significativement plus élevé chez les rats de témoins positifs que dans le groupe P8RI (p < 0,05). L'ADN libre plasmatique pendant la reperfusion chez les rats de témoins positifs augmente significativement plus que celle des rats du groupe P8RI (p< 0,05). P8RI n'a aucun effet sur le compte neutrophilaire sanguin, mais induit une diminution significative de CD31 clivé dans le plasma pendant l'I/R mésentérique (p < 0,01). Les corrélations entre l'abrasion épithéliale et l'ADN libre, MMP-9, CD31 clivé plasmatiques, les taux de MMP-9 et MPO intestinale suggèrent que le mécanisme protecteur de P8RI implique l'inhibition de l'activation neutrophilaire, y compris le clivage de CD31. Conclusions: Cette étude suggère que le traitement par le peptide P8RI, un agoniste de CD31, réduit de la façon préventive, la lésion I/R de l'intestin grêle chez les rats. / Background: Intestinal ischemia/reperfusion (I/R) injury is associated with a high mortality. The roleof transmigration of PMNs is probably essential in I/R-induced intestinal barrier dysfunction andsubsequent necrosis. The aim of this study was to evaluate, at a preclinical level, the potentialtherapeutic value of P8RI peptide (a CD31 agonist), in small bowel I/R injury.Methods: Intestinal I/R was induced in Wistar rats by superior mesenteric artery (SMA) clamping for30 min followed by 4 h of reperfusion. Three groups of rats were compared: P8RI (n=20, I/R and P8RI2.5mg/kg/h infusion), I/R positive controls (n=21, I/R and normal saline infusion), and sham operatednegative controls (n=14, SMA dissection with no clamping and normal saline infusion). Plasma,peritoneal fluid and intestinal matrix metallopeptidase 9 (MMP-9), intestinal MPO, plasma cf-DNA,intraluminal hemoglobin levels and epithelial thickness were all evaluated as intermediate markers ofintestinal injury. Detection of E.coli genetic material by quantitative PCR in blood was also performedin I/R controls and P8RI-treated rats during the reperfusion period. Plasma cleaved CD31 wasmeasured by homemade ELISA.Results: The small bowel histologic grade in P8RI-treated animals was higher than in I/R controls (p <0.05). P8RI protected against epithelial destruction induced by I/R injury (p < 0.01). There was asignificant negative correlation between epithelial abrasion and Chiu's score of histologic grading ofmesenteric I/R injury (r = -0.7245, p < 0.001). P8RI protected the small bowel from in situ MPO andMMP-9 release (p < 0.05) and digestive bleeding complications due to I/R injury (p < 0.01). Theincreased plasma and peritoneal MMP-9 levels induced by I/R were significantly reduced by P8RI (p <0.05 and p < 0.01, respectively). Plasma cf-DNA during reperfusion in I/R controls increasedsignificantly more than in the P8RI group (p < 0.05). E.coli DNA was significantly higher in I/Rcontrols than in the P8RI group (p < 0.05). P8RI had no effect on blood neutrophil counts but induceda significant diminution of cleaved CD31 in plasma during mesenteric I/R (p < 0.01). Correlationsbetween epithelial abrasion and plasma cf-DNA, MMP-9, cleaved CD31, intestinal MMP-9 and MPOlevels suggest that the protective mechanism of P8RI might involve the inhibition of neutrophilactivation, including CD31 cleavage.Conclusions: This study suggests that a treatment by P8RI peptide, a CD31 agonist, reduces smallbowel I/R injury in rats

A long held hypothesis in mitochondrial biology holds that increases in mitochondrial Ca2+ levels stimulate the activity of matrix dehydrogenases that catalyze production of NADH and eventually donate electrons to electron transport in order to increase ATP formation. At the same time, mitochondrial Ca2+ overload is a deleterious event leading to opening of the mitochondrial permeability transition pore, increasing reactive oxygen species and initiating pathways that contribute to cell death. These fundamental hypotheses are best studied in the heart because of the critical energy supply-demand relationship in myocardium, but were untestable in vivo until the discovery of the mitochondrial Ca2+ uniporter (MCU). The molecular identity of the MCU pore forming subunit was recently discovered, which allowed me to study a transgenic mouse with myocardial delimited expression of a dominant negative MCU. My lab developed mice with myocardial-delimited transgenic expression of a dominant negative MCU to test these fundamental hypotheses and to determine how MCU controls physiological and pathological stress responses in vivo, ex vivo, and in situ. My studies provide new, unanticipated information that contributes to our understanding the relationship between mitochondrial Ca2+, oxygen utilization, cardiac pacemaking and pathologic stress responses in heart. Here, I show that mice with myocardial-targeted MCU inhibition have hearts with surprisingly high oxygen consumption rates due to elevated cytoplasmic Ca2+ in response to physiological stress. Loss of MCU effectively preserved inner mitochondrial membrane potential and prevented an oxidative burst thought to drive myocardial injury and death, but nevertheless failed to protect myocardium from ischemia-reperfusion injury. Increases in oxygen consumption, elevation in cytoplasmic Ca2+ and transcriptional reprogramming mitigate the protective actions of MCU inhibition in vivo. Mice with myocardial selective MCU inhibition have a reduced response to isoproterenol-induced heart rate increase but have normal baseline heart rates. My studies provide novel insight into how MCU contributes to myocardial Ca2+ homeostasis, metabolism, and transcription leading to surprising actions on physiological and pathophysiological responses in heart.

Eukaryotic cells are unique in their ability to form complex multicellular organisms giving rise to distinct physiological systems. However, the ability for such complexity to evolve likely stems from an early event in which endosymbiosis of an aerobic prokaryote by a eukaryotic precursor gave rise to the eukaryotic organelle we now know as mitochondria. Mitochondria are colloquially known as the “power house” of the cell due to their ability to produce ATP through oxidative phosphorylation, but perform numerous other vital functions within the cell including sequestration of cytosolic Ca2+, production and sequestration of reactive oxygen species (ROS), and initiation of various forms of cell death. Mitochondria are especially important in neurons given their high demand for ATP and the importance of Ca2+ signaling in neuron excitability and development. Neurons are highly compartmentalized and plastic cells requiring the ability to control energy supply and Ca2+ signaling locally within given specialized structures such as dendritic spines or synaptic boutons. Therefore, mitochondria must be able to localize to particular sub-cellular locales and respond functionally to signaling occurring in that environment. Mitochondrial transport and function are heavily dependent upon the ability of mitochondria to undergo opposing and reversible fission and fusion events. Mitochondrial fission and fusion are themselves regulated by GTPase enzymes which physically catalyze constriction and fusion of the mitochondrial membranes. Mutations in mitochondrial fission and fusion enzymes specifically cause neurological disease in humans and recent work has illustrated the necessity of a proper balance of mitochondrial fission in neuron development, survival, and plasticity. Despite recognizing the importance of mitochondrial fission and fusion in neuron survival, development, and function we lack a concrete understanding of how changes in the equilibrium of fission and fusion impact these processes in vivo. In this thesis we investigate how promoting or inhibiting mitochondrial fission, through phosphoregulation of the mitochondrial fission enzyme Dynamin related protein 1 (Drp1) at mitochondria, impacts neuron survival and memory in vivo. We find that inhibiting phosphorylation of Drp1 at Serine 656 (S656) at the mitochondria, through deletion of a mitochondrial targeted A kinase anchoring protein (AKAP) known as AKAP1 in mice, increases cerebral infarct volume following transient occlusion of the mid-cerebral artery. Oppositely, promoting phosphorylation of Drp1-S656 at the mitochondria, through deletion of the PP2A regulatory subunit Bβ2 which localizes the PP2A heterotrimer to mitochondria, decreases cerebral infarct volume following occlusion of the mid-cerebral artery. Mechanistic in vitro studies in primary neurons reveal these effects are dependent upon the phosphorylation state of Drp1-S656 and likely due to altered mitochondrial respiratory capacity, ROS production, and Ca2+ homeostasis. Interestingly, we also observe improved hippocampal dependent memory in mice in which AKAP1 has been deleted which also appears dependent upon the phosphorylation state of Drp1-S656 and Ca2+ homeostasis. Ultimately, these findings provide insight into how phosphoregulation of Drp1 at the mitochondria alters neuron survival and function through shifting the mitochondrial fission/fusion equilibrium and consequently mitochondrial function.

Reperfusion injury may mediate renal dysfunction following ischaemia. A murine model was developed to investigate the role of the tissue factor-thrombin-protease activated receptor pathway in renal ischaemia reperfusion injury (IRI). In this model, mice received 25 minutes of ischaemia and subsequent periods of reperfusion. C57BL6, protease activated receptor-1 (PAR-1) knockout mice, and tissue factor (TF) deficient mice were used. Following 24 hours IRI, PAR-1 deficiency resulted in protection against severe renal failure compared to the C57BL6 mice (creatinine, 118.2 ?? 6.3 vs 203 ?? 12 ??mol/l, p&lt0.001). This was confirmed by lesser tubular injury. By 48 hours IRI, this resulted in a survival benefit (survival, 87.5% vs 0%, p&lt0.001). Treatment of C57BL6 mice with hirudin, a specific thrombin inhibitor, offered renoprotection at 24 hours IRI (creatinine, 107 ?? 10 ??mol/l, p&lt0.001), leading to a 60% survival rate at 48 hours IRI (p&lt0.001). TF deficient mice expressing less than 1% of C57BL6 mouse TF were also protected (creatinine, 113.6 ?? 7 ??mol/l, p&lt0.001), with a survival benefit of 75% (p&lt0.001). The PAR-1 knockout, hirudin treated C57BL6 and TF deficient mice had reduced myeloperoxidase activity and tissue neutrophil counts compared to the C57BL6 mice, along with reduced KC and MIP-2 chemokine mRNA and protein expression. Hirudin treatment of PAR-1 knockout mice had no additional benefit over PAR-1 absence alone, suggesting no further contribution by activation of other protease activated receptors (creatinine at 24 hours IRI, 106.5 ?? 10.5 ??mol/l, p&gt0.05). Furthermore, immunofluoresence staining for fibrin(ogen) showed no difference between C57BL6 and PAR-1 knockout mice, suggesting no major contribution by fibrin in this model. Renal IRI resulted in increased levels of TF mRNA expression in the C57BL6, PAR-1 knockout, and hirudin treated C57BL6 mice compared to normal controls, suggesting that TF mRNA expression was upregulated in this model. This resulted in increased TF functional activity in the C57BL6 and PAR-1 knockout mice, but TF activity was negligible in hirudin treated C57BL6 and TF deficient mice. The data therefore suggests that the TF-thrombin cascade contributes to renal IRI by signalling via PAR-1 that then regulates chemokine gene expression and subsequent neutrophil recruitment.