Pharmacokinetics of edoxaban in EGFR-mutated non-small cell lung cancer patients with venous thromboembolism.

BACKGROUND: The risk of venous thromboembolism (VTE) is increased 7-fold in patients with cancer than in those without. Low-molecular-weight heparin is the standard treatment for cancer-associated VTE. Direct oral anticoagulants (DOACs) are not inferior to low-molecular-weight heparin with respect to the general outcome of recurrent VTE. Warfarin is associated with a risk of bleeding when used in combination with gefitinib or erlotinib which are epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs). It is unclear, however, whether combination treatments with EGFR-TKIs and DOACs pose the same risk. We aimed to identify anticancer drugs and anticoagulants that can be used safely in combination, as accompanying research to an observational study on VTE incidence rates in lung cancer patients (Rising-VTE/NEJ037 study). METHODS: Twelve patients receiving EFGR-TKI monotherapy and VTE treatment were enrolled. Blood samples were collected in time series after the first dose of edoxaban, and further samples were collected within 8-15 days after administering EGFR-TKIs. The pharmacokinetics (PK) of edoxaban were analyzed using a non-compartmental model. RESULTS: Edoxaban concentrations (30 mg once daily) were measured in eight patients. PK analyses showed no significant differences before and after co-administration of EGFR-TKIs (gefitinib, erlotinib, and afatinib). CONCLUSIONS: Our findings indicate that the PK of edoxaban was not considerably affected by co-administration of EGFR-TKIs (gefitinib, erlotinib, and afatinib).

Adding Acotiamide to Gastric Acid Inhibitors Is Effective for Treating Refractory Symptoms in Patients with Non-erosive Reflux Disease.

BACKGROUND: Approximately 30% of patients who are treated with proton pump inhibitors (PPIs) for gastroesophageal reflux disease (GERD) experience persistent symptoms. No prokinetic agent regiments are useful for symptom relief. AIMS: This study was conducted to examine the effect of adding acotiamide to PPI or vonoprazan refractory GERD. METHODS: This was a randomized, prospective, double-blind, placebo-controlled trial. Seventy-one patients were enrolled. Patients underwent upper endoscopy before initial therapy [15 reflux esophagitis and 55 non-erosive reflux disease (NERD)]. Patients with persistent reflux symptoms were administered 300 mg/day acotiamide or placebo for 2 weeks. The primary endpoint was overall treatment effect (OTE), and gastrointestinal symptoms were evaluated. High-resolution manometry (HRM) and 24-h multiple intraluminal impedance-pH (MII-pH) monitoring were conducted before and after treatment when possible. RESULTS: Seventy patients were randomized (35 acotiamide and 35 placebo). Sixteen and 10 patients in the acotiamide and placebo groups, respectively, completed MII-pH and HRM. The OTE improvement rates were 28.6% and 14.3% in patients administered acotiamide and placebo, respectively (p = 0.145). In patients with NERD, however, the OTE improvement rate and responder rate for regurgitation in the acotiamide group was significantly higher than those in the placebo group (29.6 vs. 7.1%; p = 0.030, 37.0 vs. 10.7%; p = 0.021, respectively). Acotiamide significantly reduced the total reflux episodes (p = 0.001), acid (p = 0.020), proximal reflux (p = 0.007), and liquid reflux (p = 0.013) episodes. CONCLUSION: Adding acotiamide to gastric acid inhibitors can improve symptoms in patients with refractory NERD.

A thiol-mediated active membrane transport of selenium by erythroid anion exchanger 1 protein.

In this paper, we describe a thiol-mediated and energy-dependent membrane transport of selenium by erythroid anion exchanger 1 (AE1, also known as band 3 protein). The AE1 is the most abundant integral protein of red cell membranes and plays a critical role in the carbon dioxide transport system in which carbon dioxide is carried as bicarbonate in the plasma. This protein mediates the membrane transport of selenium, an essential antioxidant micronutrient, from red cells to the plasma in a manner that is distinct from the already known anion exchange mechanism. In this pathway, selenium bound to the cysteine 93 of the hemoglobin ß chain (Hb-Cysß93) is transported by the relay mechanism to the Cys317 of the amino-terminal cytoplasmic domain of the AE1 on the basis of the intrinsic interaction between the two proteins and is subsequently exported to the plasma via the Cys843 of the membrane-spanning domain. The selenium export did not occur in plain isotonic buffer solutions and required thiols, such as albumin, in the outer medium. Such a membrane transport mechanism would also participate in the export pathways of the nitric oxide vasodilator activity and other thiol-reactive substances bound to the Hb-Cysß93 from red cells to the plasma and/or peripherals.

Thiol-dependent membrane transport of selenium through an integral protein of the red blood cell membrane.

The molecular details of the selenium metabolism and transport in living systems are still not completely understood, despite their physiological importance. Specifically, little is known about the membrane transport of selenium from most of the selenium containing compounds. In the present study, we investigated the mechanism for the membrane transport of selenium from red blood cells (RBCs) to the blood plasma. When the selenium distribution in the RBC ghost membrane after treatment with selenious acid was analyzed, nearly 70% of the selenium in the membrane was found to bind to the anion exchanger 1 (AE1) protein, which suggested that the integral protein AE1 is responsible for the membrane transport of selenium. The thiol dependency of the selenium export from the RBC to the blood plasma was examined using membrane permeable thiol reagents, i.e., N-ethylmaleimide (NEM) and tetrathionate (TTN). Treatment of the RBC with NEM, a thiol-alkylating reagent, resulted in modification of the thiol groups in the amino-terminal cytoplasmic domain (N-CPD) of the AE1, but not those in the membrane domain. Such an NEM treatment provided a marked inhibition of the selenium export from the RBC to the blood plasma. In addition, the treatment with TTN, a thiol-oxidizing reagent that forms intermolecular disulfide bonds, appeared to oxidize thiol groups in both the N-CPD and the membrane domain of AE1, which resulted in complete inhibition of the selenium export even during the initial period in which the export had a maximum velocity when using the thiol reagent-free treatment. Such complete inhibition of the selenium export from the TTN-treated RBC appeared to be due to the oligomerized AE1 proteins resulting from the intermolecularly formed disulfide bonds. These inhibitory effects using NEM and TTN suggested that thiol groups in the integral protein AE1 play essential roles in the membrane transport of the selenium from the RBCs to the blood plasma.

Albumin-mediated selenium transfer by a selenotrisulfide relay mechanism.

In this study, we demonstrated a human serum albumin (HSA)-mediated selenium transfer; the selenium exported from red blood cells (RBCs) was bound to HSA through the selenotrisulfide and then transferred into the hepatocyte. After the treatment of the RBCs with selenite, the selenium efflux from the RBCs occurred in an HSA concentration-dependent manner. Pretreatment of HSA with iodoacetamide almost completely inhibited the selenium efflux from the RBC to the HSA solution. The selenium efflux experiment was carried out in an HSA solution (45 mg/mL), and subsequently the HSA solution was subjected to gel permeation chromatographic separation. The peak fraction of the selenium content was consistent with that of the HSA. The selenium bound to HSA in this solution was completely eliminated by a treatment with penicillamine (Pen), which resulted in the generation of penicillamine selenotrisulfide, PenSSeSPen. The selenium efflux from the RBCs was also occurred in a Pen solution, and PenSSeSPen was observed in the resulting Pen solution. The selenium exported from the RBC was thought to bind to the HSA via a selenotrisulfide linkage with its single free thiol. A model of the selenium-bound HSA was prepared by the reaction of the HSA with PenSSeSPen. The selenium from PenSSeSPen can bind to HSA by a thiol exchange between Pen and the free thiol of HSA, which produces the selenotrisulfide-containing HSA (HSA-SSeSPen). When HSA-SSeSPen was incubated with isolated rat hepatocytes, the selenium content in the hepatocytes increased along with its decrease in the incubation medium. To verify the results from the model experiments using HSA-SSeSPen, we conducted the HSA-mediated selenium transfer experiment from RBC treated with selenite to the hepatocytes. The selenotrisulfide-containing HSA was able to transport the selenium into the hepatocyte. Overall, the selenium transfer from the RBC to the hepatocytes involves a relay mechanism of thiol exchange that occurs between the selenotrisulfide and thiol compounds (selenotrisulfide relay mechanism: R-SSeS-R + HSA-SH --> HSA-SSeS-R + R'-SH --> R-SSeS-R').