No abstract

COVID-19 patients may exhibit neuropsychiatric and/or neurological symptoms. We found that anxiety and cognitive impairment are manifested by 28-56% of SARS-CoV-2-infected individuals with mild or no respiratory symptoms and are associated with altered cerebral cortical thickness. Using an independent cohort, we found histopathological signs of brain damage in 19% of individuals who died of COVID-19. All of the affected brain tissues exhibited foci of SARS-CoV-2 infection, particularly in astrocytes. Infection of neural stem cell-derived astrocytes changed energy metabolism, altered key proteins and metabolites used to fuel neurons and for biogenesis of neurotransmitters, and elicited a secretory phenotype that reduces neuronal viability. Our data support the model where SARS-CoV-2 reaches the brain, infects astrocytes and triggers neuropathological changes that contribute to the structural and functional alterations in the brain of COVID-19 patients.

COVID-19 patients may exhibit neuropsychiatric and neurological symptoms. We found that anxiety and cognitive impairment are manifested by 28-56% of SARS-CoV-2-infected individuals with mild respiratory symptoms and are associated with altered cerebral cortical thickness. Using an independent cohort, we found histopathological signs of brain damage in 25% of individuals who died of COVID-19. All of the affected brain tissues exhibited foci of SARS-CoV-2 infection and replication, particularly in astrocytes. Infection of neural stem cell-derived astrocytes changed energy metabolism, altered key proteins and metabolites used to fuel neurons and for biogenesis of neurotransmitters, and elicited a secretory phenotype that reduces neuronal viability. Our data support the model where SARS-CoV-2 reaches the brain, infects astrocytes and triggers neuropathological changes that contribute to the structural and functional alterations in the brain of COVID-19 patients.

Previous studies have shown that the most threatening and arousing pictures prompt the greatest evidence of defensive activation. Emotional ratings of Brazilian warning pictures described them as unpleasant but moderately arousing. To intensify avoidance of the packages, future graphic warnings should therefore generate more arousal. The ratings for the Brazilian warning pictures indicated that, except for those depicting people smoking, judgements by smokers and non-smokers were similar, suggesting a potential applicability in both prevention and cessation. Smoking cues, however, should be avoided.

It is well established that dorsal root ganglion (DRG) cells synthesize prostaglandin. However, the role that prostaglandin plays in the inflammatory hyperalgesia of peripheral tissue has not been established. Recently, we have successfully established a technique to inject drugs (3 μL) directly into the L5-DRG of rats, allowing in vivo identification of the role that DRG cell-derived COX-1 and COX-2 play in the development of inflammatory hyperalgesia of peripheral tissue. IL-1β (0.5 pg) or carrageenan (100 ng) was administered in the L5-peripheral field of rat hindpaw and mechanical hyperalgesia was evaluated after 3 h. Administration of a nonselective COX inhibitor (indomethacin), selective COX-1 (valeryl salicylate), or selective COX-2 (SC-236) inhibitors into the L5-DRG prevented the hyperalgesia induced by IL-1β. Similarly, oligodeoxynucleotide-antisense against COX-1 or COX-2, but not oligodeoxynucleotide-mismatch, decreased their respective expressions in the L5-DRG and prevented the hyperalgesia induced by IL-1β in the hindpaw. Immunofluorescence analysis demonstrated that the amount of COX-1 and COX-2, constitutively expressed in TRPV-1 + cells of the DRG, significantly increased after carrageenan or IL-1β administration. In addition, indomethacin administered into the L5-DRG prevented the increase of PKCe expression in DRG membrane cells induced by carrageenan. Finally, the administration of EP1/EP2 (7.5 ng) or EP4 (10 μg) receptor antagonists into L5-DRG prevented the hyperalgesia induced by IL-1β in the hindpaw. In conclusion, the results of this study suggest that the inflammatory hyperalgesia in peripheral tissue depends on activation of COX-1 and COX-2 in C-fibers, which contribute to the induction and maintenance of sensitization of primary sensory neurons.D uring tissue injury, prostaglandin-E 2 (PGE 2 ) is produced by the activation of the enzyme cyclooxygenase (COX) to play an important role in inflammatory hyperalgesia. PGE 2 sensitizes peripheral nociceptors through the activation of PGE 2 receptors (EP) (1). This sensitization, characterized by a reduction of nociceptive threshold and by an increase in peripheral afferent neuron responsiveness, is the main feature of inflammatory hyperalgesia in the peripheral tissue. The widespread use of nonsteroidal antiinflammatory drugs to control inflammatory hyperalgesia exemplifies the relevance of PGE 2 for the development of inflammatory hyperalgesia. These drugs decrease peripheral inflammatory hyperalgesia by inhibiting COX and, therefore, by preventing the synthesis of PGE 2 (2, 3).The COX enzyme is expressed in two major isoforms, COX-1 and COX-2, with different biological functions (4), although both play a role in the inflammatory hyperalgesia (5, 6). The isoform of COX constitutively expressed in dorsal root ganglion (DRG) is still unclear. Although COX-1 mRNA and, to a lesser extent, COX-2 mRNA have been detected in DRG cultures (7) under basal conditions, immunohistochemical studies have shown that DRG cells express only COX-1, but not C...