Background: No clinically proven effective antiviral strategy exists for the epidemic Coronavirus Disease 2019 (COVID-19). Methods: We conducted a prospective, randomized, controlled, open-label multicenter trial involving adult patients with COVID-19. Patients were randomly assigned in a 1:1 ratio to receive conventional therapy plus Umifenovir (Arbidol) (200mg*3/day) or Favipiravir (1600mg*2/first day followed by 600mg*2/day) for 10 days. The primary outcome was clinical recovery rate of Day 7. Latency to relief for pyrexia and cough, the rate of auxiliary oxygen therapy (AOT) or noninvasive mechanical ventilation (NMV) were the secondary outcomes. Safety data were collected for 17 days. Results: 240 enrolled COVID-19 patients underwent randomization; 120 patients were assigned to receive Favipiravir (116 assessed), and 120 to receive Arbidol (120 assessed). Clinical recovery rate of Day 7 does not significantly differ between Favipiravir group (71/116) and Arbidol group (62/120) (P=0.1396, difference of recovery rate: 0.0954; 95% CI: -0.0305 to 0.2213). Favipiravir led to shorter latencies to relief for both pyrexia (difference: 1.70 days, P<0.0001) and cough (difference: 1.75 days, P0.05). The most frequently observed Favipiravir-associated adverse event was raised serum uric acid (16/116, OR: 5.52, P=0.0014). Conclusions: Among patients with COVID-19, Favipiravir, compared to Arbidol, did not significantly improve the clinically recovery rate at Day 7. Favipiravir significantly improved the latency to relief for pyrexia and cough. Adverse effects caused Favipiravir are mild and manageable. This trial is registered with Chictr.org.cn (ChiCTR2000030254).

Toll-like receptor 4 (TLR4) is a crucial receptor in neuroinflammation and apoptotic neuronal death, and increasing evidences indicated that β2-microglobulin (B2M) is thought to be a major contributor to age-related cognitive decline. In present study, we designed to investigate the effects of TLR4 on B2M-induced age-related cognitive decline. Wild-type (WT) C57BL/6, TLR4 knockout (TLR4 -KO) mice and hippocampal neurons from the two type mice were respectively divided into two groups: (1) Veh group; (2) B2M-treated group. The behavioral responses of mice were measured using Morris Water Maze. Hippocampal neurogenesis and neuronal damage, inflammatory response, apoptosis, synaptic proteins and neurotrophic factors, and TLR4/MyD88/NF-κB signaling pathway proteins were examined using molecular biological or histopathological methods. The results showed that WT mice received B2M in the DG exhibited age-related cognitive declines, increased TLR4 mRNA expression and high levels of interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α) and apoptotic neuronal death in the hippocampus, which were partially attenuated in TLR4-KO mice. Moreover, in absence of TLR4, B2M treatment improved hippocampus neurogenesis and increased synaptic related proteins. Our cell experiments further demonstrated that deletion of TLR4 could significantly increase synaptic related protein, decrease neuroinflammatory fators, inhibited apoptotic neuronal death, and regulated MyD88/NF-κB signal pathway after B2M treatment. In summary, our results support the TLR4 contributes to B2M-induced age-related cognitive decline due to neuroinflammation and apoptosis through TLR4/MyD88/NF-κB signaling pathway via a modulation of hippocampal neurogenesis and synaptic function. This may provide an important neuroprotective mechanism for improving age-related cognitive decline.

Neurocognitive impairment risk increases with age and is further enhanced after anaesthesia, resulting in significant long-term morbidity and an overall reduced quality of life. Metformin activates autophagy, a key process that protects against cognitive dysfunction. We hypothesized that metformin mitigates sevoflurane-induced neurocognitive impairment by regulating autophagy and explored the underlying molecular mechanisms in aged mice. Twenty-month-old mice were exposed to 3 % sevoflurane for 2 h with or without metformin pretreatment. Cognitive function was assessed using the Morris water maze. Hippocampal synaptic integrity was determined by quantifying microtubule-associated protein 2 (MAP2), postsynaptic density protein-95 (PSD95) and synaptic density. Autophagy activity and AMP-activated protein kinase (AMPK) and ULK1 phosphorylation in the hippocampus were also measured. Metformin pretreatment attenuated the sevoflurane-induced spatial learning and memory impairment. Concomitantly, the hippocampal synaptic density and MAP2 and PSD95 immunoreactivity were significantly reduced by sevoflurane exposure but showed partial recovery in the metformin-pretreated group. These metformin-mediated neuroprotective effects were abrogated by 3-methyladenine, an autophagy inhibitor. Furthermore, sevoflurane anaesthesia decreased autophagic activity, but this activity was enhanced by metformin, accompanied by AMPK activation and ULK1 phosphorylation. The AMPK inhibitor compound C abolished metformin-induced ULK1 phosphorylation and autophagy activation after anaesthesia. These results suggest that metformin attenuates sevoflurane-induced neurocognitive impairment through AMPK-ULK1-dependent autophagy in aged mice. Metformin could become a useful drug to ameliorate cognitive impairment in elderly patients after anaesthesia and surgery.

Sevoflurane, which is widely used in paediatric anaesthesia, induces neural apoptosis in the developing brain and cognitive impairment in young mammals. Glucose hypometabolism is the key pathophysiological modulator of cognitive dysfunction. However, the effects and mechanism of sevoflurane on cerebral glucose metabolism after its use as an anaesthetic and its complete elimination are still unknown. We therefore investigated the influence of sevoflurane on neuronal glucose transporter isoform 3 (GLUT3) expression, glucose metabolism and apoptosis in vivo and in vitro and on neurocognitive function in young mice 24 h after the third exposure to sevoflurane. Postnatal day 14 (P14) mice and neural cells were exposed to 3% sevoflurane 2 h daily for three days. We found that sevoflurane anaesthesia decreased GLUT3 gene and protein expression in the hippocampus and temporal lobe, consistent with a decrease in glucose metabolism in the hippocampus and temporal lobe observed by [18F] fluorodeoxyglucose positron emission tomography (18F-FDG PET). Moreover, sevoflurane anaesthesia increased the number of TUNEL-positive cells and the levels of Bax, cleaved caspase 3 and cleaved PARP and reduced Bcl-2 levels in the hippocampus and temporal lobe. Young mice exposed to sevoflurane multiple times also showed learning and memory impairment. In addition, sevoflurane inhibited GLUT3 expression in primary hippocampal neurons and PC12 cells. GLUT3 overexpression in cultured neurons ameliorated the sevoflurane-induced decrease in glucose utilization and increase in the apoptosis rate. These data indicate that GLUT3 deficiency may contribute to sevoflurane-induced learning and memory deficits in young mice.