Cardiac hypertrophy is a compensatory response to increased work load or stress on the heart, but over time can lead to heart failure and death. The molecular mechanisms underlying this disease are still not completely understood, however the Rho/Rho kinase pathway has been shown to play a role. N-[11C]-methyl-hydroxyfasudil, a PET radiotracer, binds to active Rho kinase and could be a possible tracer for hypertrophy. Hypertrophy was induced in vitro using the β-adrenergic receptor agonist isoproterenol to evaluate optimal Rho kinase activity. Rho kinase activity data was correlated to N-[11C]-methyl-hydroxyfasudil binding. Cardiac hypertrophy was verified with an increase in nuclear size (1.74 fold) and cell size (~2 fold), activation of hypertrophic signalling pathways, and increased Rho kinase activity (1.64 fold). This correlated to a 10.3% increase in N-[11C]-methyl-hydroxyfasudil binding. This data suggests that N-[11C]-methyl-hydroxyfasudil may be useful as a radiotracer for detecting cardiac hypertrophy and merits further in vivo investigation.

In vivo, biomechanical stress plays an important role in tissue physiology and pathology, affecting cell and tissue behavior. Even though conventional outflow tissues in the eye are constantly exposed to dynamic changes in intraocular pressure (IOP), the effects of such biomechanical stressors on outflow tissue function have not been analyzed. In particular, changes in IOP with each heartbeat have been measured in human eyes approximating 2.7 mmHg/sec. The purpose of this dissertation is to determine the effect(s) of ocular pulse on conventional outflow tissue regulation and the effect that contractility plays in this mechanical stress-mediated response. The central hypothesis directing this research is that cyclic intraocular pulsations (i.e. ocular pulse) play a significant role in conventional outflow facility.In order to address our hypothesis we studied the effect of biomechanical stressors on conventional outflow physiology using three different strategies: (1) by comparing conventional outflow endothelial cells to blood and lymphatic capillary endothelia, we gained a better understanding of the effects of biomechanical stress on conventional outflow tissue physiology, (2) by modifying the anterior segment perfusion model, we were able to measure the effect of ocular pulse on conventional outflow facility, and (3) by exposing trabecular meshwork cell monolayers to cyclic biomechanical pressure oscillations in the presence of compounds known to affect trabecular meshwork contractility, we were able to analyze the effect of rho-kinase-mediated contractility on the ocular pulse-associated response.Perfused human and porcine anterior segments showed a significant ocular pulse-mediated decrease in outflow facility; in addition, perfused trabecular meshwork monolayers showed an increase in intra-chamber pressure when exposed to cyclic pressure oscillations. This effect was blocked by Y27632 inhibition of rho-kinase-mediated contraction.In conclusion, the work shown in this dissertation demonstrates for the first time that trabecular outflow tissues are capable of responding to a physiologically-relevant cyclic biomechanical stress. This response can be observed as an increase in outflow resistance that translates to lower baselines in outflow facility of anterior segments and lower hydraulic conductivity of trabecular meshwork monolayers. In addition, we concluded that the observed ocular pulse-mediated response of trabecular meshwork cells is regulated by rho-kinase-induced contractility.

Chronic neonatal pulmonary hypertension (PHT) frequently presents with rightventricular (RV) dysfunction. In neonatal rats exposed to chronic hypoxia, RV dysfunction is reversed by sustained rescue treatment with a Rho-kinase (ROCK) inhibitor – the caveat being systemic hypotension. We therefore examined the reversing effects of pulmonary-selective ROCK inhibition. Rat pups were exposed to air or hypoxia from birth for 21 days and received sustained rescue treatment with aerosolized Fasudil (81 mg/ml t.i.d for 15 min) or i.p. Y27632 (15 mg/kg b.i.d) from days 14-21. Inhaled Fasudil normalized pulmonary vascular resistance, and reversed pulmonary vascular remodeling but did not improve RV systolic function. Systemic, but not pulmonary-selective, ROCK inhibition attenuated increased RV ROCK activity. Our findings indicate that RV dysfunction in chronic hypoxic PHT is not merely a result of increased afterload, but rather may be due to increased activity of ROCK in the right ventricle.

Chronic neonatal pulmonary hypertension (PHT) frequently presents with rightventricular (RV) dysfunction. In neonatal rats exposed to chronic hypoxia, RV dysfunction is reversed by sustained rescue treatment with a Rho-kinase (ROCK) inhibitor – the caveat being systemic hypotension. We therefore examined the reversing effects of pulmonary-selective ROCK inhibition. Rat pups were exposed to air or hypoxia from birth for 21 days and received sustained rescue treatment with aerosolized Fasudil (81 mg/ml t.i.d for 15 min) or i.p. Y27632 (15 mg/kg b.i.d) from days 14-21. Inhaled Fasudil normalized pulmonary vascular resistance, and reversed pulmonary vascular remodeling but did not improve RV systolic function. Systemic, but not pulmonary-selective, ROCK inhibition attenuated increased RV ROCK activity. Our findings indicate that RV dysfunction in chronic hypoxic PHT is not merely a result of increased afterload, but rather may be due to increased activity of ROCK in the right ventricle.

Cardiac hypertrophy is a compensatory response to increased work load or stress on the heart, but over time can lead to heart failure and death. The molecular mechanisms underlying this disease are still not completely understood, however the Rho/Rho kinase pathway has been shown to play a role. N-[11C]-methyl-hydroxyfasudil, a PET radiotracer, binds to active Rho kinase and could be a possible tracer for hypertrophy. Hypertrophy was induced in vitro using the β-adrenergic receptor agonist isoproterenol to evaluate optimal Rho kinase activity. Rho kinase activity data was correlated to N-[11C]-methyl-hydroxyfasudil binding. Cardiac hypertrophy was verified with an increase in nuclear size (1.74 fold) and cell size (~2 fold), activation of hypertrophic signalling pathways, and increased Rho kinase activity (1.64 fold). This correlated to a 10.3% increase in N-[11C]-methyl-hydroxyfasudil binding. This data suggests that N-[11C]-methyl-hydroxyfasudil may be useful as a radiotracer for detecting cardiac hypertrophy and merits further in vivo investigation.

No description available.

Primary open angle glaucoma (POAG) is a leading cause of blindness worldwide. Elevated intraocular pressure (IOP), resulting from increased aqueous humor outflow resistance, is a major risk factor for the development and progression of POAG. Outflow resistance in the trabecular outflow pathway is mainly (50-75%) generated in the juxtacanalicular connective tissue (JCT), and partially (25-50%) in the portion distal to the inner wall of Schlemm’s canal. The details of how aqueous humor flows through these tissues and how resistance in these tissues is regulated are not fully understood in normal and POAG eyes. Aqueous humor outflow was shown to be “segmental”, with discontinuous active regions of aqueous humor filtration along the trabecular outflow pathway that can be labeled with perfused fluorescent tracers and measured as effective filtration area (EFA). In this study, we investigated the relationship between changes in EFA along the trabecular outflow pathway and outflow facility/IOP under two experimental conditions. The first experiment was designed to increase outflow facility by using netarsudil, a recently approved Rho kinase inhibitor class glaucoma medication, in normal human donor eyes. The second experiment was designed to increase IOP with topical steroid treatment for 5 weeks in mice. The purpose of this study is to verify whether EFA can be modulated by netarsudil or steroid treatment and to demonstrate the morphological changes that may be responsible for the changes of EFA. We analyzed EFA along the trabecular outflow pathway and found that elevated/reduced EFA correlated with increased outflow facility/IOP. Guided by EFA, we performed detailed morphological comparison between the active and inactive portions of aqueous humor filtration tissue to evaluate possible structural changes involved in EFA regulation. We found that increased EFA was associated with a loosened JCT structure and dilated episclearal veins, while decreased EFA was associated with a compacted JCT structure, increased deposition of curly collagen and/or fibrillary structure in the trabecular meshwork, and increased basement membrane continuity. Our data suggest that the netarsudil/steroid-induced morphological changes in the trabecular outflow pathway can result in either an increase or decrease in EFA, which in turn contributes to the regulation of outflow facility/IOP. / 2020-10-24T00:00:00Z

Orientador: Edson Antunes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T11:05:17Z (GMT). No. of bitstreams: 1 Calmasini_FabianoBeraldi_M.pdf: 937196 bytes, checksum: e7b4d280e06537641c107fb45b2ceb67 (MD5) Previous issue date: 2013 / Resumo: A próstata é densamente inervada pelo sistema nervoso autônomo simpático, parassimpático e não-adrenérgico não-colinérgico (NANC) os quais atuam sinergicamente para o correto funcionamento deste órgão. O principal representante da inervação NANC é o óxido nítrico (NO), porém sua função na próstata ainda não está bem definida. Sendo assim, o presente trabalho utilizou o modelo de inibição crônica da NO sintase (NOS) com L-NAME para avaliar possíveis alterações funcionais, morfológicas e bioquímicas da musculatura lisa prostática (MLP) em ratos adultos Wistar (200-250 g). Os ratos foram tratados por 4 semanas com L-NAME na dose de 20 mg/kg/dia através de ingesta hídrica. Especificamente, realizamos os seguintes experimentos na próstata dos ratos controles e tratados com L-NAME: 1) curvas concentração-efeito in vitro à fenilefrina (agonista ?1-adrenérgico) e ao carbacol (agonista muscarínico não seletivo), na presença e ausência do inibidor seletivo da rho-quinase Y27632 (1 uM), e curvas concentração-efeito ao agonista purinérgico, ?,?-metileno ATP, e à estimulação elétrica (contração neurogênica); 2) curvas concentração-efeito a agentes relaxantes como nitroprussiato de sódio (doador de NO), Y27632 (inibidor da rho-quinase) e isoproterenol (agonista ?-adrenérgico); 3) determinação dos níveis de AMPc e GMPc; e 4) análise histomorfométrica. A próstata dos animais tratados cronicamente com L-NAME apresentou aumento em seu peso relativo, alterações histomorfométricas caracterizadas como aumento na área epitelial e na muscular lisa e diminuição no índice de contorno dos ácinos. A contração da MLP induzida pela fenilefrina, carbacol, ?,?-metileno ATP e estímulo elétrico foi maior nos animais tratados cronicamente com L-NAME em relação aos animais controle. A incubação in vitro com o inibidor da rho-quinase, Y27632, restaurou ao nível controle as contrações aumentadas induzidas pela fenilefrina e carbacol no grupo L-NAME. O relaxamento da MLP nos animais do grupo L-NAME produzido pelo isoproterenol foi significativamente menor comparado ao grupo controle. Não houve diferença para o relaxamento induzido pelo SNP e Y27632 entre os grupos. Os níveis de AMPc e GMPc na próstata dos animais tratados cronicamente com L-NAME foram significativamente menores em relação aos animais do grupo controle. O tratamento com L-NAME não alterou os níveis das espécies reativas de oxigênio. Em suma, nossos dados mostram que a inibição crônica de NO leva a alterações funcionais in vitro da MLP caracterizadas por aumento na resposta contrátil à fenilefrina, carbacol, ?,?-metileno ATP e ao estímulo elétrico, além de redução no relaxamento ?-adrenérgico. A inibição da via da rho-quinase in vitro restaurou os padrões contráteis para os agonistas adrenérgicos e colinérgicos. A deficiência crônica de NO gera alterações funcionais, bioquímicas e morfológicas em próstata de ratos com participação da via da rho-quinase nesse processo / Abstract: The prostate is densely innervated by the sympathetic and parasympathetic as well as non-adrenergic non-cholinergic (NANC) autonomic innervation that act synergistically for its correct functioning. The main NANC mediator is nitric oxide (NO), but the role of this mediator in the regulation of prostate smooth muscle (PSM) is not well established. Thus, the present study used the model of chronic NOS inhibition with L-NAME to evaluate the functional, morphological and biochemical alterations in PSM of Wistar adult male rats (200-250 g). Rats were treated with L-NAME (20 mg/kg/day) for 4 weeks in the drinking water. Specifically, we performed the following experiments in prostates from control and L-NAME-treated rats: 1) in vitro concentration-response curves to phenylephrine (?1-adrenergic agonist) and carbachol (non-selective muscarinic agonist) in the presence and absence of the selective rho-kinase inhibitor Y27632 (1 ?M) and concentration-response curves to the purinergic agonist ?-?-methylene-ATP, as well as electrical stimulation (neurogenic contraction); 2) in vitro concentration-response curves to the relaxing agents sodium nitroprusside (NO donor), Y27632 (rho-kinase inhibitor) and isoproterenol (non-selective ?-adrenergic receptor agonist); 3) determination of cAMP and cGMP levels, and 4) histomorphometric analysis. The relative weight of the prostate from L-NAME-treated rats was greater than control animals. Histomorphometric changes characterized by an increase in epithelial acini and smooth muscle area, as well as by a decrease in luminal contour índex were found in L-NAME treated rats. The phenylephrine and carbachol-induced prostate contractions were higher in L-NAME compared with control group. Prior incubation of PSM with the rho-kinase inhibitor Y27632 (1 ?M) significantly inhibited the enhanced carbachol- and phenylephrine-induced PSM contractions in L-NAME group, restoring the Emax to control levels. The PSM contractions induced by ?,?-methylene ATP and electrical field stimulation were also greater in L-NAME compared with control group. The PSM-induced relaxations in response to SNP remained unaltered, whereas isoproterenol-induced relaxations were lower in L-NAME compared with control group. The cAMP and cGMP levels in prostate homogenate were lower in L-NAME compared with control group. No difference was found in reactive oxygen species levels. In summary, our data showed that chronic NO inhibition led to in vitro functional changes in PSM characterized by increased contractile response to phenylephrine, carbachol, ?-?-methylene-ATP and electrical-field stimulation, accompanied by reduction of ?-adrenergic-induced relaxation. The in vitro inhibition of rho-kinase pathway restored the contractile pathway for the adrenergic and cholinergic agonists. The chronic NO-deficiency generates functional, biochemical and morphological changes in rat prostate with involvement of the rho-kinase pathway in this process / Mestrado / Farmacologia / Mestre em Farmacologia

Cardiac hypertrophy is a compensatory response to increased work load or stress on the heart, but over time can lead to heart failure and death. The molecular mechanisms underlying this disease are still not completely understood, however the Rho/Rho kinase pathway has been shown to play a role. N-[11C]-methyl-hydroxyfasudil, a PET radiotracer, binds to active Rho kinase and could be a possible tracer for hypertrophy. Hypertrophy was induced in vitro using the β-adrenergic receptor agonist isoproterenol to evaluate optimal Rho kinase activity. Rho kinase activity data was correlated to N-[11C]-methyl-hydroxyfasudil binding. Cardiac hypertrophy was verified with an increase in nuclear size (1.74 fold) and cell size (~2 fold), activation of hypertrophic signalling pathways, and increased Rho kinase activity (1.64 fold). This correlated to a 10.3% increase in N-[11C]-methyl-hydroxyfasudil binding. This data suggests that N-[11C]-methyl-hydroxyfasudil may be useful as a radiotracer for detecting cardiac hypertrophy and merits further in vivo investigation.

With high energy consumption and a low capacity for energy storage, the brain is highly dependent on a continuous supply of oxygen and nutrients from the bloodstream. Ischemic stroke, caused by the occlusion of a cerebral blood vessel, compromises cerebral blood flow (CBF), resulting in detrimental effects on brain homeostasis, vascular function, and neuronal health. Sex differences in ischemic stroke are known, with women having lower rates of stroke due to a protective role of estrogens on vascular health, and more severe strokes following reduced estrogen production after menopause. Rho-associated protein kinase (ROCK), an important regulator of vascular tone, also regulates vascular function in a sex-specific manner, and its deletion is neuroprotective following ischemic stroke. The current study explores the overlapping roles of ROCK and endogenous hormone influence on the acute CBF response to a photothrombotic (PT) model of ischemic stroke in mice. CBF was measured following stroke in the somatosensory cortex in mice with a heterozygous deletion of the ROCK2 isoform (ROCK2+/-) and in wild-type (WT) littermates. To remove endogenous hormones, male mice were gonadectomized (Gdx) and female mice were ovariectomized (Ovx), and control animals received a sham surgery (“intact”) prior to stroke induction. Intact WT males showed a delayed CBF drop compared to intact WT females, where peak drop in CBF wasn’t observed until 48 hours following stroke. Gonadectomy in males did not alter this response, however ovariectomy in females produced a “male-like” response. ROCK2+/- males also showed such phenotypic response, and Gdx did not alter this response, suggesting ROCK2 deletion or endogenous male hormones do not alter CBF response in males in this stroke model. Alternatively, intact ROCK2+/- females showed a striking difference in CBF values compared to intact WT females, where they displayed higher CBF values immediately post-stroke and also showed a peak drop in CBF at 48 hours post-stroke. Ovx did not change the CBF response in ROCK2+/- females. Overall, there is a marked difference between males and females in their acute CBF responses to PT stroke, which appears to be mediated by endogenous female sex hormones and ROCK2. All groups except for intact WT females show a delayed drop in CBF values, reaching a maximal drop in CBF at 48 hours following stroke induction. This may be due to hyperreactivity of female platelets and upregulation of RhoA/ROCK signaling in female platelets. Further research is required to confirm this speculation. This study reveals important sex-differences and the involvement of ROCK2 in acute CBF responses to PT stroke in mice.