Stress as an immunomodulator: liver X receptors maybe the answer

Potential mechanisms of cerebrovascular diseases in COVID-19 patients

Since the outbreak of coronavirus disease 2019 (COVID-19) in 2019, it is gaining worldwide attention at the moment. Apart from respiratory manifestations, neurological dysfunction in COVID-19 patients, especially the occurrence of cerebrovascular diseases (CVD), has been intensively investigated. In this review, the effects of COVID-19 infection on CVD were summarized as follows: (I) angiotensin-converting enzyme 2 (ACE2) may be involved in the attack on vascular endothelial cells by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), leading to endothelial damage and increased subintimal inflammation, which are followed by hemorrhage or thrombosis; (II) SARS-CoV-2 could alter the expression/activity of ACE2, consequently resulting in the disruption of renin-angiotensin system which is associated with the occurrence and progression of atherosclerosis; (III) upregulation of neutrophil extracellular traps has been detected in COVID-19 patients, which is closely associated with immunothrombosis; (IV) the inflammatory cascade induced by SARS-CoV-2 often leads to hypercoagulability and promotes the formation and progress of atherosclerosis; (V) antiphospholipid antibodies are also detected in plasma of some severe cases, which aggravate the thrombosis through the formation of immune complexes; (VI) hyperglycemia in COVID-19 patients may trigger CVD by increasing oxidative stress and blood viscosity; (VII) the COVID-19 outbreak is a global emergency and causes psychological stress, which could be a potential risk factor of CVD as coagulation, and fibrinolysis may be affected. In this review, we aimed to further our understanding of CVD-associated COVID-19 infection, which could improve the therapeutic outcomes of patients. Personalized treatments should be offered to COVID-19 patients at greater risk for stroke in future clinical practice.

Blood Cytokine Concentration in Rats during Antigenic Treatment after a Single Long-Term Stress Exposure

We studied changes in the blood cytokine profile of rats 3 h, 1 day, and 8 days after acute stress on the model of 24-h immobilization followed by LPS administration (100 μg/kg intraperitoneally). The concentration of proinflammatory cytokines (particularly of IL-1β and TNFα) significantly decreased at the early stage after stress exposure and physiological saline injection, but increased in the follow-up period and practically did not differ or even surpassed the control level by the end of observations. Under these conditions, the blood content of anti-inflammatory cytokine IL-10 increased most significantly on day 1 of the post-stress period. Restraint stress followed by LPS administration was accompanied by a decrease in the level of proinflammatory cytokines at the early (IFNγ and TNFα) and late stages (IL-1β) of the experiment. Directed modulation of the immune status in animals after acute stress was followed by a significant increase in the content of IL-10 on days 1 and 8, as well as by a tendency toward elevation of IL-4 concentration by the end of the study. The directionality and degree of changes in the cytokine profile of mammalian tissues depend on the type of extreme exposure, duration of the post-stress period, and specific effects of exogenous pathogenic factors in the whole body.