Dabigatran Etexilate Induces Cytotoxicity in Rat Gastric Epithelial Cell Line via Mitochondrial Reactive Oxygen Species Production

Nonvitamin K oral anticoagulants with proton pump inhibitor cotherapy ameliorated the risk of upper gastrointestinal bleeding

Proton pump inhibitors (PPIs) can reduce the risk of upper gastrointestinal bleeding (UGIB) in patients who are taking oral anticoagulants. This study aimed to identify the association between NOACs with PPI cotherapy and UGIB. This retrospective cohort analysis included patients over the age of 18 years who were using NOACs between 2013 and 2020. NOAC categories, concomitant medications, endoscopic findings, the HAS-BLED score and the Charlson Comorbidity Index score were recorded. Using Poisson regression models, the relationship between UGIB events and risk factors was analyzed. Throughout a mean follow-up of 29.5 months, 14 (5.1%) individuals experienced UGIB. The incidence of UGIB was greater in patients receiving NOACs without PPIs (2.7 [1.26-5.60] per 1000) than in those receiving NOACs with PPIs (1.3 [0.61-2.67] per 1000). Patients receiving NOACs with PPIs had a 79.2% lower incidence of UGIB than patients receiving NOAC monotherapy (RR 0.208, 95% CI 0.061-0.706; p = 0.012). Female sex and the HAS-BLED score were associated with UGIB (RR 5.043; 95% CI 1.096-23.20; p = 0.038; RR 2.024; 95% CI 1.095-3.743; p = 0.024, respectively). Patients receiving NOAC and PPI cotherapy had a lower incidence of UGIB than those receiving NOACs alone, and female sex was a risk factor for UGIB in NOAC-treated patients.

Therapeutic Potential of Seaweed-Derived Laminaran: Attenuation of Clinical Drug Cytotoxicity and Reactive Oxygen Species Scavenging

β-glucan has been shown to be effective for several diseases such as immune regulation and blood pressure suppression. Seaweed contains a β-1,3/1,6-glucan called laminaran. The present commercial source of β-glucan is black yeast; however, a fermentation process using organic carbon substrates makes production unsustainable, whereas macroalgae provide a sustainable alternative with the use of CO₂ and seawater as growth substrates. However, bioactivity studies on laminaran are limited. We aimed to evaluate whether laminaran can scavenge reactive oxygen species (ROS) and attenuate cytotoxicity caused by clinical drugs such as indomethacin (Ind) and dabigatran (Dab). Electron spin resonance assay revealed that laminaran scavenged singlet oxygen (¹O₂) and superoxide anions (O₂^•-) directly but did not scavenge hydroxyl radicals (^•OH). Mitochondrial ROS detection dye showed that laminaran scavenged mitochondrial O₂^•- produced upon administration of Ind or Dab. Moreover, significant reductions in ^•OH and peroxynitrate (ONOO^-) levels were observed. Since ^•OH and ONOO^- are generated from O₂^•- in the cells, laminaran could indirectly suppress the generation of ^•OH and ONOO^- via the removal of O₂^•-. Both Ind and Dab induce cell injury via ROS production. Laminaran attenuated the cytotoxicity derived from these drugs and may represent a functional food with anti-aging and disease prevention properties.

Gastrointestinal Bleeding Due to NOACs Use: Exploring the Molecular Mechanisms

Novel oral anticoagulants (NOACs) are drugs approved for the prevention and treatment of many thromboembolic cardiovascular conditions as a safer alternative to warfarin. We reviewed studies published in PubMed^®, UpToDate^®, Web of Science^®, and Cochrane^® about NOACs' risks and benefits in patients requiring anticoagulation, with a focus on gastrointestinal bleeding and on molecular and pathophysiological mechanisms underlying the risk of bleeding in patients treated with them. Apixaban resulted in a lower rate of gastrointestinal bleeding compared to dabigatran and rivaroxaban. However, data reported that gastrointestinal bleeding in patients treated with NOACs was less severe compared to warfarin. Studies show promising results on the increased and widespread use of NOACs in patients who require anticoagulation (for example-in case of atrial fibrillation or high risk of venous thromboembolism), reporting an overall lower risk of major bleeding events. The profile of NOACs was more effective and secure compared to warfarin, but a more careful medical prescription is required in patients who are at high risk of gastrointestinal bleeding.

Mitochondrial Effects of Common Cardiovascular Medications: The Good, the Bad and the Mixed

Mitochondria are central organelles in the homeostasis of the cardiovascular system via the integration of several physiological processes, such as ATP generation via oxidative phosphorylation, synthesis/exchange of metabolites, calcium sequestration, reactive oxygen species (ROS) production/buffering and control of cellular survival/death. Mitochondrial impairment has been widely recognized as a central pathomechanism of almost all cardiovascular diseases, rendering these organelles important therapeutic targets. Mitochondrial dysfunction has been reported to occur in the setting of drug-induced toxicity in several tissues and organs, including the heart. Members of the drug classes currently used in the therapeutics of cardiovascular pathologies have been reported to both support and undermine mitochondrial function. For the latter case, mitochondrial toxicity is the consequence of drug interference (direct or off-target effects) with mitochondrial respiration/energy conversion, DNA replication, ROS production and detoxification, cell death signaling and mitochondrial dynamics. The present narrative review aims to summarize the beneficial and deleterious mitochondrial effects of common cardiovascular medications as described in various experimental models and identify those for which evidence for both types of effects is available in the literature.