RESUMO
PURPOSE: Testing of investigational drugs in animal models is a critical step in drug development. Current models of pulmonary hypertension (PH) have limitations. The most relevant outcome parameters such as pulmonary artery pressure (PAP) are measured invasively which requires anesthesia of the animal. We developed a new canine PH model in which pulmonary vasodilators can be characterized in conscious dogs and lung selectivity can be assessed non-invasively. METHODS: Telemetry devices were implanted to measure relevant hemodynamic parameters in conscious dogs. A hypoxic chamber was constructed in which the animals were placed in a conscious state. By reducing the inspired oxygen fraction (FiO2) to 10%, a hypoxic pulmonary vasoconstriction was induced leading to PH. The PDE-5 inhibitor sildenafil, the current standard of care was compared to atrial natriuretic peptide (ANP). RESULTS: The new hypoxic chamber provided a stable hypoxic atmosphere during all experiments. The mean PAP under normoxic conditions was 15.8 ± 1.8 mmHg. Hypoxia caused a reliable increase in mean PAP (+ 12.2 ± 3.2 mmHg, p < 0.0001). Both, sildenafil (- 6.8 ± 4.4 mmHg) and ANP (- 6.4 ± 3.8 mmHg) significantly (p < 0.05) decreased PAP. Furthermore sildenafil and ANP showed similar effects on systemic hemodynamics. In subsequent studies, the in vitro effects and gene expression pattern of the two pathways were exemplified. CONCLUSIONS: By combining the hypoxic environment with the telemetric approach, we could successfully establish a new acute PH model. Sildenafil and ANP demonstrated equal effects regarding pulmonary selectivity. This non-invasive model could help to rapidly screen pulmonary vasodilators with decreased animal burden.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Hipertensão Pulmonar/tratamento farmacológico , Artéria Pulmonar/efeitos dos fármacos , Vasodilatadores/farmacologia , Animais , Fator Natriurético Atrial/farmacologia , Fator Natriurético Atrial/uso terapêutico , Modelos Animais de Doenças , Cães , Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/fisiopatologia , Hipóxia/complicações , Pulmão/efeitos dos fármacos , Pulmão/fisiopatologia , Masculino , Artéria Pulmonar/fisiopatologia , Citrato de Sildenafila/farmacologia , Citrato de Sildenafila/uso terapêutico , Telemetria/métodos , Vasodilatadores/uso terapêutico , VigíliaRESUMO
Specific interference with molecular mechanisms guiding tissue localization of leukocytes may be of great utility for selective immunosuppressive therapies. We have discovered and characterized efomycines, a new family of selective small-molecule inhibitors of selectin functions. Members of this family significantly inhibited leukocyte adhesion in vitro. Efomycine M, which was nontoxic and showed the most selective inhibitory effects on selectin-mediated leukocyte-endothelial adhesion in vitro, significantly diminished rolling in mouse ear venules in vivo as seen by intravital microscopy. In addition, efomycine M alleviated cutaneous inflammation in two complementary mouse models of psoriasis, one of the most common chronic inflammatory skin disorders. Molecular modeling demonstrated a spatial conformation of efomycines mimicking naturally occurring selectin ligands. Efomycine M might be efficacious in the treatment of human inflammatory disorders through a similar mechanism.
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Selectina E/efeitos dos fármacos , Leucócitos/efeitos dos fármacos , Macrolídeos/farmacologia , Psoríase/tratamento farmacológico , Animais , Anti-Inflamatórios não Esteroides/química , Adesão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Feminino , Humanos , Técnicas In Vitro , Macrolídeos/química , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Modelos Moleculares , Oligossacarídeos/química , Psoríase/patologia , Antígeno Sialil Lewis X , Transplante de Pele , Streptomyces/química , Transplante HeterólogoRESUMO
During the last decades it turned out that the NO/cGMP signaling cascade is one of the most prominent regulators of a variety of physiological and pathophysiological processes in a broad range of mammalian tissues. Thus cGMP is a key second messenger and targeting this pathway by increasing intracellular cGMP levels is a very successful approach in pharmacology as shown for nitrates, PDE5 inhibitors and more recently for stimulators of the guanylate cyclase. Besides the beneficial effects of cGMP elevation in cardiac, vascular, pulmonary, renal or liver disorders the launch of PDE5 inhibitors for the treatment of erectile dysfunction 10 years ago, has directed a lot of attention to the NO/cGMP signaling in the lower urinary tract. Triggered by the use of PDE5 inhibitors in ED it turned out that cGMP is a common regulatory mechanism for lower urinary tract function also beyond ED. In recent years intense research and development efforts were undertaken to elucidate the role of the NO/cGMP and to fully exploit the therapeutic implications of cGMP elevation in urological disorders in ED and beyond. Therefore we have summarized the effects of cGMP elevation for treatment of erectile dysfunction in males and in females. We have also reviewed the recent pre-clinical and clinical lines of evidence for treatment options of benign prostatic hyperplasia and lower urinary tract symptoms in male patients and overactive bladder and urinary incontinence in female patients. In addition we also touch more speculative concepts using cGMP elevating drugs for the treatment of premature ejaculation, peyornies disease and stone disease.
Assuntos
GMP Cíclico/metabolismo , Óxido Nítrico/metabolismo , Transdução de Sinais , Animais , Disfunção Erétil/tratamento farmacológico , Disfunção Erétil/fisiopatologia , Feminino , Humanos , Masculino , Nefrolitíase/tratamento farmacológico , Nefrolitíase/fisiopatologia , Induração Peniana/tratamento farmacológico , Induração Peniana/fisiopatologia , Hiperplasia Prostática/tratamento farmacológico , Hiperplasia Prostática/fisiopatologia , Disfunções Sexuais Fisiológicas/tratamento farmacológico , Disfunções Sexuais Fisiológicas/fisiopatologia , Bexiga Urinária Hiperativa/tratamento farmacológico , Bexiga Urinária Hiperativa/fisiopatologia , Incontinência Urinária/tratamento farmacológico , Incontinência Urinária/fisiopatologiaRESUMO
INTRODUCTION: Quantitative assessment of renal function by measurement of glomerular filtration rate (GFR) is an important part of safety and efficacy evaluation in preclinical drug development. Existing methods are often time consuming, imprecise and associated with animal burden. Here we describe the comparison between GFR determinations with sinistrin (PS-GFR) and fluorescence-labelled sinistrin-application and its transcutaneous detection (TD-GFR) in a large animal model of chronic kidney disease (CKD). METHODS: TD-GFR measurements compared to a standard method using i.v. sinistrin were performed in a canine model. Animals were treated with one-sided renal wrapping (RW) followed by renal artery occlusion (RO). Biomarker and remote hemodynamic measurements were performed. Plasma sinistrin in comparison to transcutaneous derived GFR data were determined during healthy conditions, after RW and RW+RO. RESULTS: RW alone did not led to any significant changes in renal function, neither with PS-GFR nor TD-GFR. Additional RO showed a rise in blood pressure (+68.0mmHg), plasma urea (+28.8mmol/l), creatinine (+224,4µmol/l) and symmetric dimethylarginine (SDMA™; +12.6µg/dl). Plasma sinistrin derived data confirmed the expected drop (-44.7%, p<0.0001) in GFR. The calculated transcutaneous determined Fluorescein Isothiocyanate (FITC)-sinistrin GFR showed no differences to plasma sinistrin GFR at all times. Both methods were equaly sensitive to diagnose renal dysfunction in the affected animals. DISCUSSION: Renal function assessment using TD-GFR is a valid method to improve preclinical drug discovery and development. Furthermore, TD-GFR method offers advantages in terms of reduced need for blood sampling and thus decreasing animal burden compared to standard procedures.
Assuntos
Taxa de Filtração Glomerular/fisiologia , Rim/fisiopatologia , Insuficiência Renal Crônica/fisiopatologia , Administração Cutânea , Animais , Biomarcadores/metabolismo , Pressão Sanguínea/efeitos dos fármacos , Creatinina/metabolismo , Modelos Animais de Doenças , Cães , Fluoresceínas/metabolismo , Corantes Fluorescentes/metabolismo , Rim/metabolismo , Testes de Função Renal/métodos , Oligossacarídeos/metabolismo , Ureia/sangueRESUMO
BACKGROUND: Heart failure (HF) remains the most common reason for hospital admission in patients aged >65 years. Despite modern drug therapy, mortality and readmission rates for patients hospitalized with HF remain high. This necessitates further research to identify early patients at risk for readmission to limit hospitalization by timely adjustment of medical therapy. Implantable devices can monitor left ventricular (LV) hemodynamics and remotely and continuously detect the early signs of decompensation to trigger interventions and reduce the risk of hospitalization for HF. Here, we report the first preclinical study validating a new batteryless and easy to implant LV-microelectromechanical system to assess LV performance. METHODS AND RESULTS: A miniaturized implantable wireless pressure sensor was adapted for implantation in the LV apex. The LV-microelectromechanical system sensor was tested in a canine model of HF. The wireless pressure sensor measurements were compared with invasive left heart catheter-derived measurements at several time points. During different pharmacological challenge studies with dobutamine or vasopressin, the device was equally sensitive compared with invasive standard procedures. No adverse events or any observable reaction related to the implantation and application of the device for a period of 35 days was observed. CONCLUSIONS: Our miniaturized wireless pressure sensor placed in the LV (LV-microelectromechanical system) has the potential to become a new telemetric tool to earlier identify patients at risk for HF decompensation and to guide the treatment of patients with HF.
Assuntos
Insuficiência Cardíaca/diagnóstico , Hemodinâmica , Tecnologia de Sensoriamento Remoto/instrumentação , Transdutores de Pressão , Função Ventricular Esquerda , Animais , Cateterismo Cardíaco , Estimulação Cardíaca Artificial , Modelos Animais de Doenças , Dobutamina/administração & dosagem , Cães , Ecocardiografia , Desenho de Equipamento , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Hemodinâmica/efeitos dos fármacos , Masculino , Miniaturização , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Fatores de Tempo , Vasopressinas/administração & dosagem , Função Ventricular Esquerda/efeitos dos fármacosRESUMO
Vardenafil and sildenafil are potent and specific phosphodiesterase type 5 (PDE 5) inhibitors. In human penile cavernosal smooth muscle cells, we have previously shown that vardenafil has a lower biochemical inhibition constant (Ki) than sildenafil. In this study, we compared the efficacy of vardenafil and sildenafil in facilitating penile erection in a rabbit model. Penile erections were elicited by submaximal (2.5 or 6 Hz) pelvic nerve stimulation (PNS) repeated every 5 minutes for 30 minutes with or without intravenous (i.v.) administration of vardenafil (1-30 microg/kg) or sildenafil (10-30 microg/kg). Erectile response was assessed by continuously recording intracavernosal pressure (ICP) and systemic arterial pressure (SAP). All data were expressed as a ratio of ICP:SAP. I.v. administration of either PDE 5 inhibitor facilitated PNS-induced erection and increased ICP:SAP in a dose-dependent manner, reaching peak response at approximately 5 minutes. However, the threshold dose at which facilitation of erection occurred was lower for vardenafil (3 microg/kg) than for sildenafil (10 microg/kg). At the 10-microg/kg dose (i.v.), the response duration was significantly greater with vardenafil (169 +/- 23 seconds) than with sildenafil (137 +/- 31 seconds). Direct intracavernosal (i.c.) injection of 1-30 microg/kg vardenafil or sildenafil also caused dose-dependent increases in ICP:SAP in the absence of PNS. Response durations increased in a dose-dependent manner and lasted more than 5 times that of i.v. drug administration coupled with PNS. Irrespective of the route of administration (i.c. or i.v.), at equivalent doses, vardenafil was significantly more efficacious than sildenafil in facilitating pelvic nerve-mediated penile erection and in eliciting erection in the absence of PNS. The increases in ICPs occurred more quickly, were of larger magnitude, and were sustained for longer durations for vardenafil than for sildenafil. On the basis of the biochemical data and physiological responses from this study, further clinical evaluation of vardenafil as treatment for erectile dysfunction is warranted.
Assuntos
Imidazóis/farmacologia , Ereção Peniana/efeitos dos fármacos , Piperazinas/farmacologia , Vasodilatadores/farmacologia , Anestesia , Animais , Pressão Sanguínea/efeitos dos fármacos , Relação Dose-Resposta a Droga , Estimulação Elétrica , Plexo Hipogástrico/fisiologia , Injeções Intravenosas , Masculino , Modelos Animais , Pênis/inervação , Pênis/fisiologia , Pressão , Purinas , Coelhos , Citrato de Sildenafila , Sulfonas , Triazinas , Dicloridrato de VardenafilaAssuntos
Adenina/análogos & derivados , Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/metabolismo , Pirazóis/farmacologia , Piridinas/farmacologia , Receptores Citoplasmáticos e Nucleares/agonistas , 3',5'-GMP Cíclico Fosfodiesterases , Adenina/farmacologia , Animais , Aorta/efeitos dos fármacos , Aorta/enzimologia , Plaquetas/efeitos dos fármacos , Plaquetas/enzimologia , Células CHO/efeitos dos fármacos , Células CHO/enzimologia , Cricetinae , Cricetulus , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5 , Feminino , Genitália/efeitos dos fármacos , Genitália/enzimologia , Guanilato Ciclase , Humanos , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/enzimologia , Piperazinas/farmacologia , Purinas , Pirazóis/administração & dosagem , Piridinas/administração & dosagem , Coelhos , Ratos , Citrato de Sildenafila , Guanilil Ciclase Solúvel , SulfonasAssuntos
Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/química , 3',5'-GMP Cíclico Fosfodiesterases , GMP Cíclico/fisiologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5 , Disfunção Erétil/tratamento farmacológico , Humanos , Hipertensão Pulmonar/tratamento farmacológico , Masculino , Inibidores de Fosfodiesterase/química , Inibidores de Fosfodiesterase/uso terapêutico , Diester Fosfórico Hidrolases/genética , Diester Fosfórico Hidrolases/fisiologia , Pirimidinonas/farmacologia , Relação Estrutura-AtividadeRESUMO
Soluble guanylate cyclase (sGC) is a key signal-transduction enzyme activated by nitric oxide (NO). Impairments of the NO-sGC signaling pathway have been implicated in the pathogenesis of cardiovascular and other diseases. Direct stimulation of sGC represents a promising therapeutic strategy particularly for the treatment of pulmonary hypertension (PH), a disabling disease associated with a poor prognosis. Previous sGC stimulators such as the pyrazolopyridines BAY 41-2272 and BAY 41-8543 demonstrated beneficial effects in experimental models of PH, but were associated with unfavorable drug metabolism and pharmacokinetic (DMPK) properties. Herein we disclose an extended SAR exploration of this compound class to address these issues. Our efforts led to the identification of the potent sGC stimulator riociguat, which exhibits an improved DMPK profile and exerts strong effects on pulmonary hemodynamics and exercise capacity in patients with PH. Riociguat is currently being investigated in phase III clinical trials for the oral treatment of PH.
Assuntos
Pirimidinas/química , Receptores Citoplasmáticos e Nucleares/agonistas , Administração Oral , Animais , Cães , Descoberta de Drogas , Feminino , Guanilato Ciclase/metabolismo , Hipertensão Pulmonar/tratamento farmacológico , Morfolinas/química , Morfolinas/farmacologia , Óxido Nítrico/metabolismo , Pirazóis/química , Pirazóis/farmacologia , Piridinas/química , Piridinas/farmacologia , Pirimidinas/síntese química , Pirimidinas/farmacocinética , Pirimidinas/farmacologia , Coelhos , Ratos , Receptores Citoplasmáticos e Nucleares/metabolismo , Transdução de Sinais , Guanilil Ciclase Solúvel , Relação Estrutura-AtividadeRESUMO
INTRODUCTION: Administration of serotonin reuptake inhibitors (SRI) or serotonin and norepinephrine reuptake inhibitors (SNRI) relieves depressive symptoms but may cause sexual dysfunction in women and men. AIM: The aim of the present study was to evaluate the effects of the phosphodiesterase type 5 (PDE5) inhibitor, vardenafil, on inhibition of genital vascular responses (GVR) induced by SRI or SNRI administration in female rabbits. METHODS: Vaginal and clitoral vasodilatory responses to pelvic nerve electrical stimulation were measured by laser Doppler flow needle probes. RESULTS: GVR were significantly potentiated by vardenafil even at the low dose of 0.1 mg/kg, in clitoris and vagina (181 +/- 22% and 180 +/- 31% of control, in vagina and clitoris, respectively, at 8 Hz). The selective SRI, paroxetine (5 mg/kg), significantly inhibited GVR in female rabbits (54 +/- 5% and 48 +/- 6% of control). GVR were also significantly inhibited by the SNRIs, venlafaxine (5 mg/kg) (57 +/- 3% and 32 +/- 11%) and duloxetine (1 mg/kg) (40 +/- 7% and 28 +/- 5%). Treatment with vardenafil (0.1 and 0.3 mg/kg) completely reversed the inhibition of GVR induced by paroxetine, venlafaxine, or duloxetine. CONCLUSIONS: Potentiation of the nitric oxide (NO) pathway by vardenafil improves vascular sexual responses in female rabbits and overcomes the inhibitory effects of acutely administered antidepressants on GVR, irrespective of the underlying pathophysiologic mechanism, i.e., disruption of the NO pathway or enhancement of alpha-adrenergic mechanisms. PDE5 inhibition may represent a reasonable approach to treat SRI- or SRNI-induced female sexual dysfunction, in particular, arousal disorders.
Assuntos
Imidazóis/farmacologia , Inibidores de Fosfodiesterase/farmacologia , Piperazinas/farmacologia , Disfunções Sexuais Fisiológicas/tratamento farmacológico , Vagina/efeitos dos fármacos , Vasodilatadores/farmacologia , Animais , Antidepressivos/efeitos adversos , Vasos Sanguíneos/efeitos dos fármacos , Estimulação Elétrica , Feminino , Imidazóis/administração & dosagem , Fluxometria por Laser-Doppler , Inibidores de Fosfodiesterase/administração & dosagem , Piperazinas/administração & dosagem , Coelhos , Fluxo Sanguíneo Regional/efeitos dos fármacos , Disfunções Sexuais Fisiológicas/etiologia , Sulfonas/administração & dosagem , Sulfonas/farmacologia , Triazinas/administração & dosagem , Triazinas/farmacologia , Vagina/irrigação sanguínea , Dicloridrato de Vardenafila , Vasodilatação/efeitos dos fármacos , Vasodilatadores/administração & dosagemRESUMO
Several different heterocyclic systems were compared as PDE5 inhibitor scaffolds. In addition to the known 3H-imidazo[5,1-f][1,2,4]triazin-4-ones and pyrazolopyrimidinones, isomeric imidazo[1,5-a][1,3,5]triazin-4(3H)-ones were also shown to be potent and selective PDE inhibitor scaffolds with in vivo activity. SAR trends were elucidated for sulfonamide derivatives with generality across different scaffolds.
Assuntos
3',5'-GMP Cíclico Fosfodiesterases/antagonistas & inibidores , Compostos Heterocíclicos/síntese química , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5 , Compostos Heterocíclicos/farmacologia , Concentração Inibidora 50 , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
We report nineteen 4-aryl- and 4-arylalkyl-1-phthalazinamines (5-8) which we prepared and tested for antithrombotic properties. All compounds were assayed for their antiplatelet activity in the "Born test" with collagen as inducer of the aggregation. N-[4-(1H-1, 2, 4-triazol-1-yl)butyl]-4-phenyl-1-phthalazin-amine (7 c) was the most potent compound, having an IC(50) of 8 microM. When 5-HT (Serotonin) was used to start aggregation the N-(furan-2-yl-methyl)-4-phenyl-1-pthtalazinamine (8 a) had an IC(50) of 2 microM. In vivo potencies were highly significant. N-[5-(1H-1, 2, 4-triazol-1-yl)pentyl]-4-phenyl-1-phthalazinamine (7 d) inhibited thrombus formation by 12% (P < 0.002) in arterioles and 7% (P < 0.01) in venoles as tested with our laser thrombosis model. For compound 8 a we surprisingly found an antagonism to the 5HT(2A) receptor, which is most likely the mechanism of the inhibition of aggregation by this compound.
Assuntos
Fibrinolíticos/farmacologia , Ftalazinas/farmacologia , Antagonistas do Receptor 5-HT2 de Serotonina , Antagonistas da Serotonina/farmacologia , Administração Oral , Animais , Colágeno/farmacologia , Desenho de Fármacos , Fibrinolíticos/síntese química , Guanilato Ciclase , Humanos , Técnicas In Vitro , Lasers , Masculino , Inibidores de Fosfodiesterase/síntese química , Inibidores de Fosfodiesterase/farmacologia , Ftalazinas/síntese química , Ratos , Ratos Wistar , Receptor 5-HT2A de Serotonina/metabolismo , Receptores Citoplasmáticos e Nucleares/agonistas , Serotonina/farmacologia , Antagonistas da Serotonina/síntese química , Guanilil Ciclase Solúvel , Relação Estrutura-Atividade , Trombose/tratamento farmacológico , Trombose/etiologiaRESUMO
Fifteen new indazole derivatives have been synthesized. In the Born test, compounds (4f) and (4g) were most active. They inhibited the blood platelet aggregation induced by collagen with an IC(50) = 85 or 90 microM, respectively. After oral administration to rats (60 mg/kg) three of the compounds significantly inhibited the formation of thrombi in arterioles and venules. The strongest effect was observed with (4j) which showed an inhibition of 15% in arterioles and 7% in venules. Further experiments showed that compound (4j) does not mediate these effects by activating soluble guanylate cyclase, but likely by inhibiting phosphodiesterase isoform PDE 5.
Assuntos
Fibrinolíticos/química , Indazóis/química , Inibidores da Agregação Plaquetária/química , 3',5'-GMP Cíclico Fosfodiesterases , Animais , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5 , Ativação Enzimática/efeitos dos fármacos , Fibrinolíticos/síntese química , Fibrinolíticos/farmacologia , Guanilato Ciclase/metabolismo , Humanos , Técnicas In Vitro , Indazóis/síntese química , Indazóis/farmacologia , Inibidores de Fosfodiesterase/síntese química , Inibidores de Fosfodiesterase/química , Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/metabolismo , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/síntese química , Inibidores da Agregação Plaquetária/farmacologia , Ratos , Trombose/prevenção & controleRESUMO
2-aryl-substituted imidazo[5,1-f][1,2,4]triazin-4(3H)-ones represent a new class of potent cGMP-PDE 5 inhibitors that prove to be superior to other purine-isosteric inhibitors. Subnanomolar inhibitors of PDE 5 with activity in in vivo models for erectile dysfunction have been identified. BAY 38-9456 (Vardenafil-hydrochloride) has been selected for clinical studies in the indication of erectile dysfunction.