Milk Casein Inhibits Effect of Black Tea Galloylated Theaflavins to Inactivate SARS-CoV-2 In Vitro.

Continuing caution is required against the potential emergence of SARS-CoV-2 novel mutants that could pose the next global health and socioeconomical threats. If virus in saliva can be inactivated by a beverage, such a beverage may be useful because the saliva of infected persons is the major origin of droplets and aerosols that mediate human-to-human viral transmission. We previously reported that SARS-CoV-2 was significantly inactivated by treatment in vitro with tea including green tea and black tea. Catechins and its derived compounds galloylated theaflavins (gTFs) bound to the receptor-binding domain (RBD) of the S-protein and blocked interaction between RBD and ACE2. Black tea is often consumed with sugar, milk, lemon juice, etc., and it remains unclarified whether these ingredients may influence the anti-SARS-CoV-2 effect of black tea. Here, we examined the effect of black tea on Omicron subvariants in the presence of these ingredients. The infectivity of Omicron subvariants was decreased to 1/100 or lower after treatment with black tea for 10 s. One or two teaspoons of milk (4~8 mL) completely blocked the anti-viral effect of a cup of tea (125 mL), whereas an addition of sugar or lemon juice failed to do so. The suppressive effect was dose-dependently exerted by milk casein but not whey proteins. gTFs were coprecipitated with casein after acidification of milk-supplemented black tea, strongly suggesting the binding of gTFs to casein. The present study demonstrates for the first time that an addition of milk cancelled the anti-SARS-CoV-2 effect of black tea due to binding of casein to gTFs.

Validating plasminogen activator inhibitor-1 as a poor prognostic factor in sepsis.

AIM: Our previous report indicated that plasminogen activator inhibitor-1 (PAI-1) levels of ≥83 ng/mL in patients with sepsis tended to be associated with disseminated intravascular coagulation (DIC), suppressed fibrinolysis, multiple organ dysfunction, and mortality. Therefore, the present study aimed to validate whether 83 ng/mL was a useful cut-off value for using PAI-1 levels to predict a poor prognosis in sepsis. METHODS: Patients with sepsis were included in this single-center retrospective study. The patients were classified as having high or low PAI-1 values (<83 ng/mL versus ≥83 ng/mL), and were compared in terms of their pre-DIC state, intensive care unit-free days, continuous renal replacement therapy-free days, ventilator-free days, catecholamine-free days, and 28-day survival rate. RESULTS: The high PAI-1 group included 61 patients (54%) and the low PAI-1 group included 52 patients (46%). The high PAI-1 group had significantly higher frequencies of a pre-DIC state within 1 week (P = 0.009). There was no significant difference in ventilator-free days. However, the high PAI-1 group had significantly lower values for intensive care unit-free days (P = 0.01), continuous renal replacement therapy-free days (P = 0.02), and catecholamine-free days (P = 0.02). The high PAI-1 group also had a significantly lower 28-day survival rate based on the Kaplan-Meier analysis (log-rank, P = 0.03). CONCLUSION: Patients with sepsis and PAI-1 levels of ≥83 ng/mL had elevated risks of coagulopathy, organ failure, and mortality. Thus, these results suggest that 83 ng/mL could be a useful cut-off value for prognostication based on PAI-1 levels in this setting.