RESUMEN
The complex pathophysiology of sickle cell anemia (SCA) involves intravascular hemolytic processes and recurrent vaso-occlusion, driven by chronic vascular inflammation, which result in the disease's severe clinical complications, including recurrent painful vaso-occlusive episodes. Hydroxyurea, the only drug frequently used for SCA therapy, is a cytostatic agent, although it appears to exert nitric oxide/soluble guanylyl cyclase (sGC) modulating activity. As new drugs that can complement or replace the use of hydroxyurea are sought to further reduce vaso-occlusive episode frequency in SCA, we investigated the effects of the sGC agonists BAY 60-2770 (sGC activator) and BAY 41-2272 (sGC stimulator) in the presence or absence of hydroxyurea on SCA vaso-occlusive mechanisms and cell recruitment both ex vivo and in vivo. These agents significantly reduced stimulated human SCA neutrophil adhesive properties ex vivo in association with the inhibition of surface ß2-integrin activation. A single administration of BAY 60-2770 or BAY 41-2272 decreased tumor necrosis factor cytokine-induced leukocyte recruitment in a mouse model of SCA vaso-occlusion. Importantly, the in vivo actions of both agonists were significantly potentiated by the coadministration of hydroxyurea. Erythroid cell fetal hemoglobin (HbF) elevation is also a major goal for SCA therapy. BAY 41-2272 but not BAY 60-2770 at the concentrations employed significantly induced γ-globin gene transcription in association with HbF production in cultured erythroleukemic cells. In conclusion, sGC agonist drugs could represent a promising approach as therapy for SCA, for use either as stand-alone treatments or in combination with hydroxyurea. SIGNIFICANCE STATEMENT: This preclinical study demonstrates that stimulators and activators of sGC are potent inhibitors of the adhesion and recruitment of leukocytes from humans and in mice with sickle cell anemia (SCA) and may represent a promising approach for diminishing vaso-occlusive episode frequency in SCA. Hydroxyurea, a drug already frequently used for treating SCA, was found to potentiate the beneficial effects of sGC agonists in in vivo studies, implying that these classes of compounds could be used alone or in combination therapy.
Asunto(s)
Anemia de Células Falciformes/tratamiento farmacológico , Anemia de Células Falciformes/metabolismo , Hidroxiurea/farmacocinética , Guanilil Ciclasa Soluble/metabolismo , Animales , Benzoatos/farmacología , Compuestos de Bifenilo/farmacología , Línea Celular Tumoral , Modelos Animales de Enfermedad , Células Eritroides/efectos de los fármacos , Células Eritroides/metabolismo , Hemoglobina Fetal/metabolismo , Humanos , Hidrocarburos Fluorados/farmacología , Células K562 , Masculino , Ratones , Ratones Endogámicos C57BL , Pirazoles/farmacología , Piridinas/farmacología , Enfermedades Vasculares/tratamiento farmacológico , Enfermedades Vasculares/metabolismo , Vasodilatadores/farmacologíaRESUMEN
Neutrophils participate in the initiation and progression of rheumatoid arthritis (RA) although the exact mechanisms responsible for neutrophil accumulation in rheumatoid joints are not understood. This study compared the adhesive and chemotactic functions of neutrophils from RA patients in activity (DAS28 > 3.2) and not in activity (DAS28 < 2.6) and observed the effects of different treatment approaches on these functions. Neutrophils were isolated from healthy controls (CON), and patients with active or inactive RA in use of therapy not specific for RA (NSAIDs), in use of DMARDs and in use of anti-TNF-α therapy. Adhesive and chemotactic properties were evaluated using in vitro assays; adhesion molecule expression was assessed by flow cytometry and real-time PCR and circulating chemokines were determined by ELISA. No significant alterations in the adhesive and chemotactic properties of neutrophils from active RA were observed when compared to CON neutrophils, independently of treatment regimen. In contrast, neutrophils from RA patients in disease remission presented reduced adhesive properties and a lower spontaneous chemotactic capacity, in association with decreased adhesion molecule expression, although profiles of alterations differed for those patients on DMARDs and those on anti-TNF-α therapy. Circulating levels of the major neutrophilic chemokines, IL-8 and epithelial neutrophil activating peptide-78, were also significantly decreased in those patients demonstrating a clinical response. Remission of RA appears to be associated with ameliorations in aspects important for neutrophil adhesion and chemotaxis; whether these alterations contribute to decrease neutrophil migration to the synovial fluid, with consequent improvements in the clinical manifestations of RA, remains to be determined.
Asunto(s)
Artritis Reumatoide/tratamiento farmacológico , Quimiocinas/sangre , Quimiotaxis de Leucocito/efectos de los fármacos , Neutrófilos/citología , Neutrófilos/efectos de los fármacos , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Adulto , Anciano , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Antirreumáticos/farmacología , Antirreumáticos/uso terapéutico , Artritis Reumatoide/sangre , Artritis Reumatoide/diagnóstico , Estudios de Casos y Controles , Adhesión Celular/efectos de los fármacos , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo , Femenino , Expresión Génica/efectos de los fármacos , Humanos , Infliximab , Interleucina-8/sangre , Interleucina-8/farmacología , Selectina L/sangre , Masculino , Persona de Mediana Edad , Neutrófilos/metabolismo , Inducción de Remisión , Adulto JovenRESUMEN
Kielmeyera coriacea Mart. (Clusiaceae), known as "Pau Santo", is used to treat several tropical diseases. The hydroethanolic extract (HE) of Kielmeyera coriacea stems and its semi-pure dichloromethane constituent (DCM) produced an anti-immobility effect in rats submitted to the forced swimming test (FST), suggesting a antidepressant-like profile. This study evaluated the effect of intra-median raphe nucleus (MRN) microinjection of 1,3,7-trihydroxy-2-(3-methylbut-2-enyl)-xanthone, present in large quantity in the HE from Kielmeyera coriacea stems, on immobility behaviour in the FST in rats. The effects of xanthone were compared with intra-MRN microinjections of Way100635 (5-HT1A antagonist) or (+) 8-OH-DPAT (5-HT1A agonist). Locomotor activity in the open-field test (OFT) was evaluated as a complementary measure. Xanthone (0.3ng) or Way100635 (2.5microg) reduced, whereas (+) 8-OH-DPAT (5.0microg) increased immobility time in the FST. Way100635 (2.5 or 5.0microg) completely reversed the effects of (+) 8-OHDPAT (5.0microg), and potentiated the anti-immobility effect of the ineffective dose of xanthone (0.2ng) in the FST. The association of effective doses of (+) 8-OH-DPAT (5.0microg) and xanthone (0.3ng) annulled the effect of each compound on immobility time. These results suggest that xanthone acts as an antagonist at 5-HT1A autoreceptors in MRN and increases serotonin (5-HT) availability in projection regions, proving to be a prototype drug that may be useful in mood isorders such as depression, or indeed be a beneficial adjunctive treatment improving the efficacy and/or accelerating the effects of antidepressant drugs in patients with major depression.
Asunto(s)
Antidepresivos/farmacología , Encéfalo/efectos de los fármacos , Clusiaceae/química , Pérdida de Tono Postural/efectos de los fármacos , Extractos Vegetales/farmacología , Antagonistas de la Serotonina/farmacología , Xantonas/farmacología , 8-Hidroxi-2-(di-n-propilamino)tetralin/farmacología , Animales , Antidepresivos/aislamiento & purificación , Locomoción/efectos de los fármacos , Masculino , Neuronas/efectos de los fármacos , Extractos Vegetales/química , Tallos de la Planta , Ratas , Ratas Wistar , Serotonina/metabolismo , Antagonistas del Receptor de Serotonina 5-HT1 , Antagonistas de la Serotonina/aislamiento & purificación , Agonistas de Receptores de Serotonina/farmacología , Xantonas/aislamiento & purificaciónRESUMEN
AIMS: To determine the pattern and the genetic basis of resistance to terbinafine, a drug extensively used for the treatment of fungal infections in humans. METHODS AND RESULTS: Four resistant mutants from Aspergillus nidulans isolated after irradiation with ultraviolet light were crossed with the master strain F (MSF). Genetic analysis revealed that a single gene, located on chromosome IV, is responsible for resistance to terbinafine and that the alleles responsible for this resistance in these mutants are of a codominant or dominant nature at high terbinafine concentrations. Furthermore, the interaction of this mutation with another one identified on chromosome II causes the double mutant to be highly resistant. CONCLUSIONS: Periodic surveillance of antimycotic susceptibility would be an important measure in detecting the emergence and spread of resistance. Mutation in a single gene could be responsible for resistance to terbinafine and a genic interaction may be responsible for a higher level of antimycotic resistance. SIGNIFICANCE AND IMPACT OF THE STUDY: The understanding of the mechanisms that lead to changes in the sensitivity of a fungus to a given antifungal agent is important both in order to define strategies for the use of such agent and to guide the development of new antifungal agents.