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Introdução: Vários fármacos têm sido avaliados para o tratamento da COVID-19, mas somente o antiviral remdesivir foi registrado nos órgãos regulatórios dos principais países desenvolvidos para esse fim. TDF e FTC demonstraram atividade contra o SARS-CoV-2 in vitro. Objetivos: Avaliar a eficácia e toxicidade de TDF e TDF/FTC em pacientes com infecção leve a moderada por COVID-19. Secundariamente, avaliamos biomarcadores de citocinas, quimiocinas e fatores de crescimento celular, associados à fisiopatogenia da COVID-19. Métodos: Ensaio clínico randomizado, duplo-cego, controlado por placebo, em pacientes com suspeita clínica de infecção respiratória leve a moderada por SARS-CoV-2. O estudo foi aprovado pela CONEP e registrado no ClinicalTrials.gov. Pacientes foram aleatoriamente recrutados para tomarem TDF (300 mg/dia) ou TDF/FTC (300/200 mg/dia) ou placebo (Vit. C - 500 mg/dia), por 10 dias. O parâmetro primário foi o escore de sintomas e sinais preditivos de COVID-19, avaliado no sétimo dia de acompanhamento dos pacientes. Resultados: 309 pacientes foram recrutados e 226 foram randomizados nos seguintes grupos: (a) 74 no grupo TDF; (b) 74 no grupo TDF/FTC; e (c) 77 no grupo placebo. Dos 226 pacientes, 139 (62%) foram positivos para o teste RT-PCR para SARS-CoV-2. Febre (≥ 37,8°C), ageusia ou disgeusia, anosmia ou disosmia e dois ou mais sintomas ou sinais clínicos foram significativamente associados com a infecção por SARS-CoV-2. Não houve alteração significativa no escore clínico baseado nos sintomas e sinais clínicos entre os grupos de tratamento. Também não houve diferença quanto aos eventos adversos e eventos adversos graves entre os grupos de tratamentos. Nenhum paciente faleceu durante o período total de 28 dias de acompanhamento do protocolo no estudo. Nos parâmetros secundários, pacientes com infecções respiratórias leve a moderadas por SARS-CoV-2 apresentaram maiores concentrações do fator de crescimento celular e citocinas pró-inflamatórias (G-CSF, IL-1β, IL-6 e TNF-α) em relação aos pacientes sem infecção por SARS-CoV-2. Conclusões: Febre (≥37,8°C), perda de olfato, perda de paladar e dois ou mais sintomas, têm maior predição para o diagnóstico de COVID-19 leve a moderada. A intervenção farmacológica com TDF ou TDF/FTC não alterou o escore de sintomas e sinais clínicos na infeção respiratória leve a moderada em pacientes com SARS-CoV-2 comparados ao grupo placebo.

Arboviruses pose a major threat throughout the world and represent a great burden in tropical countries of South America. Although generally associated with moderate febrile illness, in more severe cases they can lead to neurological outcomes, such as encephalitis, Guillain-Barré syndrome, and Congenital Syndromes. In this context astrocytes play a central role in production of inflammatory cytokines, regulation of extracellular matrix, and control of glutamate driven neurotoxicity in the central nervous system. Here, we presented a comprehensive genome-wide transcriptome analysis of human primary astrocytes infected with Chikungunya, Mayaro, Oropouche, or Zika viruses. Analyses of differentially expressed genes (DEGs), pathway enrichment, and interactomes have shown that Alphaviruses up-regulated genes related to elastic fiber formation and N-glycosylation of glycoproteins, with down-regulation of cell cycle and DNA stability and chromosome maintenance genes. In contrast, Oropouche virus up-regulated cell cycle and DNA maintenance and condensation pathways while down-regulated extracellular matrix, collagen metabolism, glutamate and ion transporters pathways. Zika virus infection only up-regulated eukaryotic translation machinery while down-regulated interferon pathways. Reactome and integration analysis revealed a common signature in down-regulation of innate immune response, antiviral response, and inflammatory cytokines associated to interferon pathway for all arboviruses tested. Validation of interferon stimulated genes by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) corroborated our transcriptome findings. Altogether, our results showed a co-evolution in the mechanisms involved in the escape of arboviruses to antiviral immune response mediated by the interferon (IFN) pathway.

Chikungunya virus (CHIKV) infection is characterized by febrile illness, severe joint pain, myalgia, and cardiovascular complications. Given that CHIKV stimulates reactive oxygen species (ROS) and pro- and anti-inflammatory cytokines, events that disrupt vascular homeostasis, we hypothesized that CHIKV induces arterial dysfunction by directly impacting redox-related mechanisms in vascular cells. Wild-type (WT) and iNOS knockout (iNOS−/−) mice were administered either CHIKV (1.0 × 106 PFU/µL) or Mock vehicle via the intracaudal route. In vivo, CHIKV infection induced vascular dysfunction (assessed by a wire myograph), decreased systolic blood pressure (tail-cuff plethysmography), increased IL-6 and IFN-γ, but not TNF-α levels (determined by ELISA), and increased protein content by Western blot. Marked contractile hyporesponsiveness to phenylephrine was observed 48 h post-infection, which was restored by endothelium removal. L-NAME, 1400W, Tiron, and iNOS gene deletion prevented phenylephrine hyporesponsiveness. CHIKV infection increased vascular nitrite concentration (Griess reaction) and superoxide anion (O2•−) generation (lucigenin chemiluminescence), and decreased hydrogen peroxide (H2O2, by Amplex Red) levels 48 h post-infection, alongside increased TBARS levels. In vitro, CHIKV infected endothelial cells (EA.hy926) and upregulated ICAM-1 and iNOS protein expression (determined by Western blot). These data support the conclusion that CHIKV-induced alterations in vascular ROS/NF-kB/iNOS/NO signaling potentially contribute to cardiovascular events associated with Chikungunya infection.