Effect of Food on the Pharmacokinetics of Tenofovir Amibufenamide: A Phase I, Randomized, Open-Label, Two-Period Crossover Trial in Healthy Adult Subjects.

Purpose: Tenofovir amibufenamide (TMF) is a novel nucleotide reverse transcriptase inhibitor. The aim of this study was to investigate the effect of food on the single-dose pharmacokinetic properties of TMF. Patients and Methods: In this open-label, randomized, crossover study, after an overnight fast, eligible subjects received a single 25 mg dose of TMF tablet, either under fasted conditions or following consumption of a high-fat, high-calorie meal, followed by a two-week washout period. Blood samples were collected until 144 h after administration. TMF and its metabolite, tenofovir (TFV), were analyzed using validated liquid chromatography-tandem mass spectrometry methods. The geometric mean ratio (GMR) and the corresponding 90% confidence interval (CI) values of AUC0-t, AUC0-∞, and Cmax were acquired for analysis. The absence of an effect of food was indicated if the 90% CI values were within the predefined equivalence limits of 80%-125%. Safety and tolerability were also assessed. Results: For TMF, adjusted GMR (90% CI) values for the fed versus fasted states were 150.28% (125.36%-180.16%), 158.24% (130.42%-192.00%), and 57.65% (45.68%-72.76%) for AUC0-t, AUC0-∞, and Cmax, respectively. For TFV, the GMR (90% CI) of Cmax was 82.00% (74.30%-90.49%) after administration under fed conditions, slightly outside the bioequivalence boundary of 80%-125%, while the corresponding values for AUC0-t and AUC0-∞ were within range. The absorption of TMF was delayed by food, with median Tmax values of 0.33 and 1.00 h in fasted and fed conditions, respectively. The adverse events observed in subjects were all mild. Conclusion: Our results demonstrated that TMF tablets were well-tolerated in healthy volunteers. When TMF tablets were taken with food, Tmax was delayed and exposures of TMF and TFV were higher than under fasted conditions. The modest changes observed are not considered clinically relevant, so TMF can be taken with or without food.

Inhibition of SK2 and ER stress ameliorated inflammation and apoptosis in liver ischemia-reperfusion injury.

Ischemia-reperfusion injury (IRI) remains a major cause of mortality and morbidity after liver surgery. Endoplasmic reticulum (ER) stress is a critical mechanism of inflammatory injury during hepatic IRI. In this study, we investigated the effect of sphingosine kinases 2 (SK2) on ER stress and hepatic IRI. We established hepatic IRI mice and hepatocellular hypoxia/reoxygenation in vitro model. We observed the SK2 and ER stress protein IRE1α expression. Then, we used an SK2 inhibitor and knocked down IRE1α/SK2, to observe the effect of SK2 during IRI. Our results showed that the expression of ER stress and SK2 was significantly elevated during hepatic IRI. Inhibition of SK2 ameliorated liver inflammation and reduced cell apoptosis in hepatic IRI mice. Consistently, we found that the inhibition of IRE1α also downregulated SK2 expression and reduced mitochondrial membrane permeability. Furthermore, the knockdown of SK2 could also reduce cell damage and reduce the expression of inflammatory factors but did not influence ER stress-related signaling pathway. Taken together, our results suggested that ER stress and SK2 played important and regulatory roles in hepatic IRI. Inhibition of ER stress and SK2 could significantly improve liver function after hepatic IRI.

Expression of STING Is Increased in Monocyte-Derived Macrophages and Contributes to Liver Inflammation in Hepatic Ischemia-Reperfusion Injury.

Ischemia/reperfusion (I/R) injury, aggravated by innate immune cell-mediated inflammatory response, is a major problem in liver transplantation. Stimulator of interferon gene (STING) is a crucial regulatory signaling molecule in the DNA-sensing pathway, and its activation can produce strong innate immunity. However, the STING-mediated innate immune pathway in hepatic I/R injury has not been fully elucidated. In this study, we first examined the STING expression changes in the liver tissues of mice after hepatic I/R injury by using quantitative polymerase chain reaction and Western blot assays. We then investigated the role of STING in I/R injury by using a murine hepatic I/R model. STING up-regulation in mouse liver tissues in response to I/R injury and STING deficiency in myeloid cells was found to significantly ameliorate I/R-induced liver injury and inflammatory responses. STING inhibitors were also able to ameliorate hepatic I/R injury. Mechanically, STING may have a protective effect on hepatic I/R injury by the inhibition of hypoxia-inducible factor-1 alpha and enhancement of phosphorylated AMP-activated protein kinase to reduce macrophage activation. These findings show the potential regulatory effects of STING in hepatic I/R and suggest a new method for clinical protection of hepatic I/R injury.