Antifungal activity of liriodenine on clinical strains of Cryptococcus neoformans and Cryptococcus gattii species complexes

Background: Cryptoccocal meningitis continues to present high incidence among AIDS patients. The treatment of choice is the synergistic combination of flucytosine (5-FC) with amphotericin B deoxycholate (AmBd) or its lipid formulations. However, 5-FC is unavailable in many countries and AmB demands hospitalization. The combination of AmB with the fungistatic fluconazole (FLC) or the use of high FLC daily doses alone became the choice. Nonetheless, sterilization of cerebrospinal fluid is delayed with FLC monotherapy, mainly with high fungal burden. These findings suggest the search for new antifungal compounds, such as liriodenine. Methods: Liriodenine antifungal activity was evaluated by three procedures: determining the minimum inhibitory concentration (MIC) on 30 strains of the Cryptococcus neoformans (C. neoformans) complex and 30 of the Cryptococcus gattii (C. gattii) complex, using EUCAST methodology and amphotericin B deoxycholate as control; performing the time-kill methodology in two strains of the C. neoformans complex and one of the C. gattii complex; and injury to cryptococcal cells, evaluated by transmission electron microscopy (TEM). Liriodenine absorption and safety at 0.75 and 1.50 mg.kg-1 doses were evaluated in BALB/c mice. Results: Liriodenine MICs ranged from 3.9 to 62.5 µg.mL-1 for both species complexes, with no differences between them. Time-kill methodology confirmed its concentration-dependent fungicidal effect, killing all the strains below the limit of detection (33 CFU.mL-1) at the highest liriodenine concentration (32-fold MIC), with predominant activity during the first 48 hours. Liriodenine induced severe Cryptococcus alterations ­ cytoplasm with intense rarefaction and/or degradation, injury of organelles, and presence of vacuoles. Liriodenine was better absorbed at lower doses, with no histopathological alterations on the digestive tract. Conclusion: The fungicidal activity confirmed by time-kill methodology, the intense Cryptococcus injury observed by TEM, the absorption after gavage administration, and the safety at the tested doses indicate that the liriodenine molecule is a promising drug lead for development of anticryptococcal agents.(AU)

Use of hyaluronic acid associated with triamcinolone acetonide or ozone gas in the treatment of induced osteoarthritis in rabbits

Purpose: To evaluate the effects of the intra-articular application of hyaluronic acid associated with triamcinolone acetonide, and ozone gas in the treatment of induced osteoarthritis in rabbit’s stifles.Methods: Twenty-one Norfolk rabbits were submitted to cranial cruciate ligament transection of the left stifle. After six weeks of the surgery, the rabbits were randomized assigned into three groups: G1 (control) – saline solution (0.9%); G2 – hyaluronic acid associated with triamcinolone; G3 – ozone gas, submitted to three intra-articular applications every seven days. Results: Significant differences occurred: osteophytes at medial femoral condyle (G2 > G1, G2 > G3) on radiography exam; thickening of the medial condyle (G1 > G3, G2 > G3) on ultrasound exam; osteophytes at lateral tibial condyle (G2 > G1, G2 > G3), and medial femoral condyle (G1 > G2, G3 > G1) on computed tomography. Histologically, mean values of chondrocytes in the femur and tibia in G3 and G2 were statistically lower. Conclusions: The intra-articular injection of hyaluronic acid associated with triamcinolone accentuated degenerative joint disease by imaging and macroscopic evaluations, and by histological findings, this treatment and the ozone gas treatment showed similar effects and were inferior to the saline solution (0.9%).

Remodelamento parenquimatoso pulmonar em dois modelos experimentais de fibrose

A fibrose pulmonar é a base patológica de uma variedade de doenças crônicas incuráveis. A IL-17A, uma glicoproteína secretada de células Th17, é uma citocina pró-fibrótica relacionada recentemente à síntese de colágeno V e fibrose pulmonar. O remodelamento parenquimatoso pulmonar da matriz extracelular pelo colágeno I e V, apoptose e resposta Th17 foi estudado em camundongos Balb/c, C57/B6J selvagens e com knockout para o receptor A da IL-17; para determinar as vias fisiopatológicas que prolongam a fase tardia do processo fibrótico induzido por bleomicina e paraquat. Microscopia eletrônica, imunofluorescência, imunohistoquímica, detecção in situ da apoptose, morfometria, reconstrução tridimensional e reação em cadeia da polimerase em tempo real foram usados para avaliar a quantidade, estrutura e cadeias moleculares dos tipos de colágenos, apoptose e células imunes. Verificamos um aumento da síntese e secreção do colágeno V que promove a perpetuação da fibrose pulmonar de maneira IL-17A dependente. Além disso, observou-se que marcadores críticos da resposta Th17 como IL17, STAT3, TGF-?, IL-6, IL- 21, IL-23 e células T CD4+ foram significantemente aumentados em cepas susceptíveis a fibrose pulmonar e intensificadas na ausência do receptor A da IL-17. O aumento de marcadores Th17 resulta em um aumento de células T CD4+ através de uma resposta imune que efetivamente bloqueia a degradação do colágeno V, o qual contribui para o bloqueio da apoptose. Nosso estudo indica que o colágeno V participa da perpetuação da fibrose pulmonar por mecanismos IL-17 dependente e independentes, indicando o potencial alvo terapêutico do colágeno V e das vias de sinalização da resposta IL-17 no tratamento das doenças fibroproliferativas pulmonares

Pulmonary fibrosis is the pathologic basis for a variety of incurable human chronic lung diseases. IL-17A, a glycoprotein secreted from IL-17? producing cells, has recently been shown to be a profibrotic cytokine involved in type V collagen synthesis and pulmonary fibrosis. Remodeling of the extracellular matrix by collagen I and V, cell death and Th-17 immune response were evaluated in Balb/c, wild and IL-17 receptor A knockout C57/B6J mice, to determine the pathways that prolong the late phase of the fibrotic process induced by bleomycin and paraquat. Electron microscopy, immunofluorescence, immunohistochemistry, in situ detection of apoptosis, morphometry, tridimensional reconstruction and a real-time PCR were used to evaluate the amount, structure and molecular chains of collagen types, apoptosis and immune cells. We verified increased synthesis and secretion of type V collagen that promoted the maintenance of pulmonary fibrosis in a IL-17A dependent manner. However, we observed that the critical Th17 markers, IL-17, STAT3, TGF-?, IL-6, IL-21, IL-23 and CD4+ T cells, were significantly increased in the fibrosis-susceptible strain and intensified in the absence of IL-17 receptor A. Increased Th17 markers resulted in an increase in CD4+ T cells in fibrotic lung tissue toward an immune response that effectively blocked degradation of collagen V, which contributes to block apoptosis. Our studies indicate that collagen V participates in the maintenance of pulmonary fibrosis in both Th-17 ? dependent and -independent manners and that collagen V and the components of the Th-17 signaling pathway are potential therapeutic targets for the treatment of fibroproliferative lung diseases