Modification of Gas6 Protein in the Brain by a Functional Endogenous Tissue Vitamin K Cycle.

The TAM receptor ligand Gas6 is known for regulating inflammatory and immune pathways in various organs including the brain. Gas6 becomes fully functional through the post-translational modification of multiple glutamic acid residues into γ-carboxyglutamic in a vitamin K-dependent manner. However, the significance of this mechanism in the brain is not known. We report here the endogenous expression of multiple components of the vitamin K cycle within the mouse brain at various ages as well as in distinct brain glial cells. The brain expression of all genes was increased in the postnatal ages, mirroring their profiles in the liver. In microglia, the proinflammatory agent lipopolysaccharide caused the downregulation of all key vitamin K cycle genes. A secreted Gas6 protein was detected in the medium of both mouse cerebellar slices and brain glial cell cultures. Furthermore, the endogenous Gas6 γ-carboxylation level was abolished through incubation with the vitamin K antagonist warfarin and could be restored through co-incubation with vitamin K1. Finally, the γ-carboxylation level of the Gas6 protein within the brains of warfarin-treated rats was found to be significantly reduced ex vivo compared to the control brains. In conclusion, we demonstrated for the first time the existence of a functional vitamin K cycle within rodent brains, which regulates the functional modification of endogenous brain Gas6. These results indicate that vitamin K is an important nutrient for the brain. Furthermore, the measurement of vitamin K-dependent Gas6 functionality could be an indicator of homeostatic or disease mechanisms in the brain, such as in neurological disorders where Gas6/TAM signalling is impaired.

Unleashing ferroptosis for cancer therapy with warfarin.

Ferroptosis holds promise for cancer therapy. A recent study by Yang et al. in Cell Metabolism reveals that VKORC1L1-mediated reduction of vitamin K inhibits ferroptosis and establishes a direct p53-VKORC1L1 link in its regulation. As warfarin can inhibit VKORC1L1, the study further underscores this drug's potential as a cancer therapy.

Exploring the complex relationship between vitamin K, gut microbiota, and warfarin variability in cardiac surgery patients.

BACKGROUND AND OBJECTIVES: Due to the high individual variability of anticoagulant warfarin, this study aimed to investigate the effects of vitamin K concentration and gut microbiota on individual variability of warfarin in 246 cardiac surgery patients. METHODS: The pharmacokinetics and pharmacodynamics (PKPD) model predicted international normalized ratio (INR) and warfarin concentration. Serum and fecal samples were collected to detect warfarin and vitamin K [VK1 and menaquinone-4 (MK4)] concentrations and gut microbiota diversity, respectively. In addition, the patient's medical records were reviewed for demographic characteristics, drug history, and CYP2C9, VKORC1, and CYP4F2 genotypes. RESULTS: The PKPD model predicted ideal values of 62.7% for S-warfarin, 70.4% for R-warfarin, and 76.4% for INR. The normal VK1 level was 1.34±1.12 nmol/ml (95% CI: 0.33-4.08 nmol/ml), and the normal MK4 level was 0.22±0.18 nmol/ml (95% CI: 0.07-0.63 nmol/ml). The MK4 to total vitamin K ratio was 16.5±9.8% (95% CI: 4.3-41.5%). The S-warfarin concentration of producing 50% of maximum anticoagulation and the half-life of prothrombin complex activity tended to increase with vitamin K. Further, Prevotella and Eubacterium of gut microbiota identified as the main bacteria associated with individual variability of warfarin. The results suggest that an increase in vitamin K concentration can decrease anticoagulation, and gut microbiota may influence warfarin anticoagulation through vitamin K2 synthesis. CONCLUSION: This study highlights the importance of considering vitamin K concentration and gut microbiota when prescribing warfarin. The findings may have significant implications for the personalized use of warfarin. Further research is needed to understand better the role of vitamin K and gut microbiota in warfarin anticoagulation.

Regulation of VKORC1L1 is critical for p53-mediated tumor suppression through vitamin K metabolism.

Here, we identified vitamin K epoxide reductase complex subunit 1 like 1 (VKORC1L1) as a potent ferroptosis repressor. VKORC1L1 protects cells from ferroptosis by generating the reduced form of vitamin K, a potent radical-trapping antioxidant, to counteract phospholipid peroxides independent of the canonical GSH/GPX4 mechanism. Notably, we found that VKORC1L1 is also a direct transcriptional target of p53. Activation of p53 induces downregulation of VKORC1L1 expression, thus sensitizing cells to ferroptosis for tumor suppression. Interestingly, a small molecular inhibitor of VKORC1L1, warfarin, is widely prescribed as an FDA-approved anticoagulant drug. Moreover, warfarin represses tumor growth by promoting ferroptosis in both immunodeficient and immunocompetent mouse models. Thus, by downregulating VKORC1L1, p53 executes the tumor suppression function by activating an important ferroptosis pathway involved in vitamin K metabolism. Our study also reveals that warfarin is a potential repurposing drug in cancer therapy, particularly for tumors with high levels of VKORC1L1 expression.

Direct oral anticoagulant (DOAC) monitoring within primary care: a quality improvement project.

BACKGROUND: Poor monitoring of anticoagulants is a significant area of patient safety. It can lead to the dichotomous risk of haemorrhage/clotting without appropriate counselling and monitoring. While healthcare professionals may be familiar with the anticoagulant warfarin and the international normalised ratio, they might be unaware of the monitoring requirements of direct oral anticoagulants (DOACs), despite DOACs making up 62% of anticoagulants prescribed. The goal of this quality improvement (QI) project was to increase the compliance of monitoring of DOACs within general practice (GP) to improve patient safety and reduce the risk of an adverse outcome for patients. LOCAL PROBLEM: In 2019, the GP surgery had 318 patients prescribed a DOAC and their medication reviews took place opportunistically. While initially, monitoring levels were nearly 100%, by December 2018 this had dropped significantly, and clinicians stated they were unfamiliar with this medication. METHODS AND INTERVENTIONS: This project aimed to resolve this by using QI methodology and Plan-Do-Study-Act (PSDA) cycles to create new sustainable processes with DOAC monitoring and aimed to increase DOAC monitoring by 20% within 6 months. RESULTS: Within 6 months, the project improved the rate of monitoring, and 49% of all patients prescribed a DOAC were seen in a DOAC clinic (n=156) and 78% (n=230/294) had DOAC counselling; 97% (n=295/304) had appropriate blood tests and 72% (n=216/298) had a recent weight recorded within their medical records. Three years on, 600 patients within the practice are prescribed DOACs and 74% (n=445) have had an annual review adhering to the gold standards set within the project. CONCLUSION: This QI project confirms that monitoring of DOACs can be improved within primary care by using QI methodology and improving patient safety, using PDSA cycles, stakeholder engagement and the introduction of the anticoagulant domains within the nationwide Quality Assurance and Improvement Framework.

Comparison of the International Normalized Ratio Between a Point-of-Care Test and a Conventional Laboratory Test: the Latter Performs Better in Assessing Warfarin-induced Changes in Coagulation Factors.

Background: Point-of-care testing (POCT) coagulometers are increasingly used for monitoring warfarin therapy. However, in high international normalized ratio (INR) ranges, significant discrepancy in the INR between POCT and conventional laboratory tests occurs. We compared the INR of POCT (CoaguChek XS Plus; Roche Diagnostics, Mannheim, Germany) with that of a conventional laboratory test (ACL TOP 750; Instrumentation Laboratory SpA, Milan, Italy) and explored possible reasons for discrepancy. Methods: Paired POCT and conventional laboratory test INRs were analyzed in 400 samples from 126 patients undergoing warfarin therapy after cardiac surgery. Coagulation factor and thrombin generation tests were compared using the Mann-Whitney U test. Correlations between coagulation factors and INRs were determined using Pearson correlation coefficients. Results: The mean difference in the INR between the tests increased at high INR ranges. Endogenous thrombin potential levels were decreased at INR <2.0 for CoaguChek XS Plus and 2.0< INR <3.0 for ACL TOP 750 compared with those at INR <2.0 for both tests, indicating a better performance of ACL TOP 750 in assessing thrombin changes. The correlation coefficients of coagulation factors were stronger for ACL TOP 750 INR than for CoaguChek XS Plus INR. Vitamin K-dependent coagulation factors were found to contribute to the INR discrepancy. Conclusions: Decreases in vitamin K-dependent coagulation and anticoagulation factors can explain the significant discrepancy between the two tests in high INR ranges. Since conventional laboratory test INR values are more reliable than POCT INR values, a confirmatory conventional laboratory test is required for high INR ranges.

A genome-wide CRISPR-Cas9 knockout screen identifies FSP1 as the warfarin-resistant vitamin K reductase.

Vitamin K is a vital micronutrient implicated in a variety of human diseases. Warfarin, a vitamin K antagonist, is the most commonly prescribed oral anticoagulant. Patients overdosed on warfarin can be rescued by administering high doses of vitamin K because of the existence of a warfarin-resistant vitamin K reductase. Despite the functional discovery of vitamin K reductase over eight decades ago, its identity remained elusive. Here, we report the identification of warfarin-resistant vitamin K reductase using a genome-wide CRISPR-Cas9 knockout screen with a vitamin K-dependent apoptotic reporter cell line. We find that ferroptosis suppressor protein 1 (FSP1), a ubiquinone oxidoreductase, is the enzyme responsible for vitamin K reduction in a warfarin-resistant manner, consistent with a recent discovery by Mishima et al. FSP1 inhibitor that inhibited ubiquinone reduction and thus triggered cancer cell ferroptosis, displays strong inhibition of vitamin K-dependent carboxylation. Intriguingly, dihydroorotate dehydrogenase, another ubiquinone-associated ferroptosis suppressor protein parallel to the function of FSP1, does not support vitamin K-dependent carboxylation. These findings provide new insights into selectively controlling the physiological and pathological processes involving electron transfers mediated by vitamin K and ubiquinone.

[Significant Prolongation of the International Normalized Ratio Associated with COVID-19 Treatment: Possible Drug Interaction with Remdesivir].

A 55-year-old man with hypertrophic cardiomyopathy and a pacemaker was admitted with coronavirus disease 2019 (COVID-19). Before admission, the patient's medications included amiodarone, diltiazem, bisoprolol, atorvastatin, etizolam, and warfarin (WF). After admission, dexamethasone (DXM) and remdesivir (RDV) were initiated for treating COVID-19. The international normalized ratio (INR) on admission was 1.8, which increased to 3.4 on day 5 and to 6.9 on day 10 after admission. Although there have been reports that RDV may occasionally prolong prothrombin time and that the degree of prolongation is often less severe, the mechanism of action has not been elucidated till date. There are reports of prolonged INR when WF is co-administered with RDV and DXM, suggesting that drug interactions may be a potential cause for the prolongation. A similar drug interaction may have potentially occurred in the case reported here. In addition, this case used amiodarone (AMD), and it has been reported that the RDV concentration increases when used in combination with AMD. Further investigations are needed to elucidate the cause of INR prolongation. Thus, close monitoring of the patient is recommended when RDV is co-administered with high-risk agents to avoid unnecessary side effects.

The combination of EGCG with warfarin reduces deep vein thrombosis in rabbits through modulating HIF-1α and VEGF via the PI3K/AKT and ERK1/2 signaling pathways.

Deep venous thrombosis (DVT) poses a major challenge to public health worldwide. Endothelial cell injury evokes inflammatory and oxidative responses that contribute to thrombus formation. Tea polyphenol (TP) in the form of epigallocatechin-3-gallate (EGCG) has anti-inflammatory and oxidative effect that may ameliorate DVT. However, the precise mechanism remains incompletely understood. The current study was designed to investigate the anti-DVT mechanism of EGCG in combination with warfarin (an oral anticoagulant). Rabbits were randomly divided into five groups. A DVT model of rats was established through ligation of the inferior vena cava (IVC) and left common iliac vein, and the animals were orally administered with EGCG, warfarin, or vehicle for seven days. In vitro studies included pretreatment of human umbilical vein endothelial cells (HUVECs) with different concentrations of EGCG for 2 h before exposure to hydrogen peroxide. Thrombus weight and length were examined. Histopathological changes were observed by hematoxylin-eosin staining. Blood samples were collected for detecting coagulation function, including thrombin and prothrombin times, activated partial thromboplastin time, and fibrinogen levels. Protein expression in thrombosed IVCs and HUVECs was evaluated by Western blot, immunohistochemical analysis, and/or immunofluorescence staining. RT-qPCR was used to determine the levels of AGTR-1 and VEGF mRNA in IVCs and HUVECs. The viability of HUVECs was examined by CCK-8 assay. Flow cytometry was performed to detect cell apoptosis and ROS generation was assessed by 2',7'-dichlorofluorescein diacetate reagent. In vitro and invivo studies showed that EGCG combined with warfarin significantly reduced thrombus weight and length, and apoptosis in HUVECs. Our findings indicated that the combination of EGCG and warfarin protects HUVECs from oxidative stress and prevents apoptosis. However, HIF-1α silencing weakened these effects, which indicated that HIF-1α may participate in DVT. Furthermore, HIF-1α silencing significantly up-regulated cell apoptosis and ROS generation, and enhanced VEGF expression and the activation of the PI3K/AKT and ERK1/2 signaling pathways. In conclusion, our results indicate that EGCG combined with warfarin modifies HIF-1α and VEGF to prevent DVT in rabbits through anti-inflammation via the PI3K/AKT and ERK1/2 signaling pathways.

In vivo evaluation of pharmacokinetic drug-drug interactions between fluorinated pyrimidine anticancer drugs, 5-fluorouracil and capecitabin, and an anticoagulant, warfarin.

Warfarin is a common anticoagulant and has demonstrated interactions with several drugs. Among them, as a serious adverse event, a case of death due to the enhanced warfarin action owing to its combined use with a fluoropyrimidine anticancer drug has been reported, but the detailed mechanism has not been elucidated.Some reports have advocated that fluorinated pyrimidine anticancer drugs reduce cytochrome P450 2C9 expression, leading to the enhanced pharmacological effects of warfarin.The purpose of this study was to clarify the mechanisms of drug-drug interactions between warfarin and 5-fluorouracil (5-FU) and capecitabine in vivo using rats. Rats were administered warfarin in combination with 5-FU (15 mg/kg/d) or capecitabine (15 mg/kg/d) for 7 d. Prothrombin time (PT) and activated partial thromboplastin time were significantly prolonged in the warfarin plus 5-FU or capecitabine groups compared with those in the warfarin alone group. No significant difference was observed in the area under the plasma concentration-time curve of the warfarin alone group compared with the warfarin with 5-FU or capecitabine groups.These data suggest that the enhancement of warfarin efficacy caused by the combination of 5-FU or capecitabine was due to a pharmacological interaction rather than a pharmacokinetic interaction.

Should patients with non-muscle-invasive bladder cancer discontinue fibrin clot inhibitors during bacille Calmette-Guérin?

OBJECTIVE: To determine the impact of fibrin clot inhibitor (FCI) use on oncological outcomes in a large contemporary cohort of patients with non-muscle-invasive bladder cancer (NMIBC) treated with adequate bacille Calmette-Guérin (BCG). PATIENTS AND METHODS: We performed an Institutional Review Board-approved review of patients with NMIBC treated with adequate intravesical BCG, at our institution between 2000 and 2018. FCI use at the time of BCG therapy was recorded for each patient. Patients were stratified according to use of FCI medication. Recurrence- and progression-free survival were analysed using Kaplan-Meier methods and Cox proportional hazard models. RESULTS: Overall, 226 of 526 patients (43.0%) used a FCI: aspirin (205), clopidogrel (38), warfarin (18) and novel oral anticoagulant (NOAC; seven). The use of FCIs did not adversely affect either recurrence- or progression-free survival (P = 0.385 and P = 0.131, respectively). These results did not change when the impact of aspirin, clopidogrel or warfarin/NOAC use on recurrence and progression was evaluated separately. On multivariate analysis, FCI use was neither associated with tumour recurrence nor progression. CONCLUSION: The use of FCIs was not associated with adverse oncological outcomes in a large contemporary cohort of patients receiving adequate intravesical BCG for NMIBC. Based on these results, FCIs may be safely continued during BCG immunotherapy.

Riesgo de sangrado en pacientes anticoagulados con antagonistas de la vitamina K que reciben antibióticos / Risk of bleeding in anticoagulated patients with vitamin K antagonists who receive antibiotics

Lograr un adecuado nivel de anticoagulación con antagonistas orales de la vitamina K suele ser un desafío frecuente en la práctica clínica, dado que su estrecho rango terapéutico suele verse afectado por diversas interacciones farmacológicas,alimentos y condiciones clínicas. A partir de un caso de un paciente anticoagulado que presenta una hemorragia gastro-intestinal posterior a realizar un tratamiento antibiótico, la autora de este artículo revisó la evidencia sobre el riesgo desangrado secundario a la interacción entre este tipo de anticoagulantes y antibióticos orales. Su conclusión tras realizar una búsqueda bibliográfica y seleccionar la mejor evidencia disponible, es que existe un aumento del riesgo relativo desangrado en pacientes anticoagulados que reciben antibióticos, por lo que deberían evitarse aquellos antibióticos con conocido potencial de interacción. Si ello no fuera posible, se recomienda monitorizar el estado de anticoagulación con dosaje de la razón internacional normatizada (RIN) posterior a la introducción del antibiótico. (AU)

Achieving an adequate level of anticoagulation with oral vitamin K antagonists is often a frequent challenge in clinical practice, given that their narrow therapeutic range is often affected by various drug interactions, food, and clinical conditions. Based on a case of an anticoagulated patient who presented gastrointestinal bleeding after antibiotic treatment, the authorof this article reviewed the evidence on the risk of secondary bleeding due to the interaction between this type of anticoagulants and oral antibiotics. Their conclusion, after performing a literature search and selecting the best available evidence, is that there is an increased relative risk of bleeding in anticoagulated patients receiving antibiotics, so antibiotics with known potential for interaction should be avoided. If it weren't possible, it is recommended to monitor the anticoagulation status with International Normalized Ratio (INR) dosing after the introduction of the antibiotic. (AU)

Molecular Mechanism of Vitamin K2 Protection against Amyloid-ß-Induced Cytotoxicity.

The pathological role of vitamin K2 in Alzheimer's disease (AD) involves a definite link between impaired cognitive functions and decreased serum vitamin K levels. Vitamin K2 supplementation may have a protective effect on AD. However, the mechanism underlying vitamin K2 protection has not been elucidated. With the amyloid-ß (Aß) cascade hypothesis, we constructed a clone containing the C-terminal fragment of amyloid precursor protein (ß-CTF/APP), transfected in astroglioma C6 cells and used this cell model (ß-CTF/C6) to study the protective effect of vitamin K2 against Aß cytotoxicity. Both cellular and biochemical assays, including cell viability and reactive oxygen species (ROS), assays assay, and Western blot and caspase activity analyses, were used to characterize and unveil the protective role and mechanism of vitamin K2 protecting against Aß-induced cytotoxicity. Vitamin K2 treatment dose-dependently decreased the death of neural cells. The protective effect of vitamin K2 could be abolished by adding warfarin, a vitamin K2 antagonist. The addition of vitamin K2 reduced the ROS formation and inhibited the caspase-3 mediated apoptosis induced by Aß peptides, indicating that the mechanism underlying the vitamin K2 protection is likely against Aß-mediated apoptosis. Inhibitor assay and Western blot analyses revealed that the possible mechanism of vitamin K2 protection against Aß-mediated apoptosis might be via regulating phosphatidylinositol 3-kinase (PI3K) associated-signaling pathway and inhibiting caspase-3-mediated apoptosis. Our study demonstrates that vitamin K2 can protect neural cells against Aß toxicity.

Influence of CYP2C9, VKORC1, and CYP4F2 polymorphisms on the pharmacodynamic parameters of warfarin: a cross-sectional study.

BACKGROUND: Warfarin is the most commonly evaluated drug in pharmacogenetic-guided dosing studies. However, gaps remain regarding the influence of the genetic polymorphisms of CYP2C9, VKORC1, and CYP4F2 on specific pharmacodynamic parameters like the warfarin sensitivity index (WSI), prothrombin time international normalized ratio (PT-INR), and log-INR variability. METHODS: A cross-sectional study was conducted in non-smoking adults receiving warfarin for at least 6 months. Their demographics, diagnoses, warfarin dosing regimen, concomitant drugs, PT-INR, and bleeding episodes were obtained. CYP2C9 (rs1057910-*3 and rs1799853-*2 alleles), CYP4F2 (rs2108622), and VKORC1 (rs9923231) polymorphisms were assessed using real-time polymerase chain reaction. Three genotype groups (I-III) were defined based on the combined genetic polymorphisms of CYP2C9 and VKORC1 from the FDA's recommendations. Key outcome measures included anticoagulation control, time spent in therapeutic range, stable warfarin dose, WSI, log-INR variability, and Warfarin Composite Measure (WCM). RESULTS: The study recruited 236 patients; 75 (31.8%) carried a functional CYP2C9 variant allele, and, 143 (60.6%) had at least one T allele in CYP4F2 and 133 (56.4%) had at least one T allele in VKORC1. Groups' II and III CYP2C9 and VKORC1 genotypes were observed with reduced stable warfarin dose, increased WSI, higher log-INR variability, and increased bleeding risk. The presence of *2 or *3 allele in CYP2C9 was observed with reduced stable warfarin doses akin to the presence of T alleles in VKORC1; however, the doses increased with T alleles in CYP4F2. CONCLUSION: The evaluated genetic polymorphisms significantly influenced all the pharmacodynamic parameters of warfarin. Evaluating CYP2C9, VKORC1, and CYP4F2 genetic polymorphisms prior to warfarin initiation is likely to optimize therapeutic response.

Atrial Fibrillation and Use of Rivaroxaban: Performance of the Prothrombin Time / INR as a Function of Time After Blood Collection

Abstract Background Traditionally, the most effective therapy in the prevention of stroke in patients with atrial fibrillation (AF) has been oral anticoagulation with vitamin K inhibitors, particularly warfarin, whose disadvantages and adverse effects have led to their replacement by "direct oral anticoagulants", as factor X inhibitor. Objectives This study aimed to conduct a brief approach on atrial fibrillation (AF) and use of Rivaroxaban, and to comparatively evaluate the prothrombin time / International Normalized Ratio (PT/INR) in patients with AF in use of this oral anticoagulant, depending on the time elapsed between the last administration of the drug and the time of blood sample venipuncture. Methods We evaluated 34 patients with AF in use of Rivaroxaban by using PT / INR, distributed into a subgroup with blood collection time ≤ 12 hours (n = 7) and > 12 hours after the last drug intake (n = 27). Mann-Whitney test was used to compare the groups and p < 0.05 was considered significant. Results An analysis as a function of time between the Rivaroxaban intake and blood collection, revealed that PT / INR suffers the greatest effect up to 12 hours after ingestion of the drug, dropping to levels close to normal in subsequent hours before the next dose. Conclusion We concluded that, in contrast to warfarin, the knowledge of the time interval between drug intake and blood collection from patients taking Rivaroxaban is essential to properly interpret a laboratory test to assess hemostasis, particularly PT and its derivatives. Int J Cardiovasc Sci. 2020; [online].ahead print, PP.0-0

Effects of Herba Erigerontis injection on pharmacodynamics and pharmacokinetics of warfarin in rats in vivo.

Herba Erigerontis injection (HEI) is an aqueous solution derived from whole plants of Erigeron breviscapus, which may be co-administered with warfarin to treat cardiovascular and cerebrovascular disorders. This research was conducted to make sure whether HEI would affect anticoagulation of warfarin to guarantee reasonable medication. The pharmacodynamic study was designed to measure prothrombin time (PT) and activated partial thromboplastin time (APTT) values, and international normalized ratio (INR) values were calculated. For pharmacokinetic study, ultra performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) technology was applied to measure plasma concentrations of warfarin enantiomers. The influence of HEI on plasma protein binding rate of warfarin was assessed by ultrafiltration. Pharmacodynamic study demonstrated that both HEI alone and co-administered with warfarin could increase PT and INR values significantly (P < .01), whereas the APTT values were unaffected (P > .05). Pharmacokinetic study manifested that Cmax , AUC and t1/2 prolonged significantly (P < .01) for R/S-warfarin in presence of HEI. Low (3.6 mL/kg), medium (7.2 mL/kg) and high (10.8 mL/kg) doses of HEI could decrease plasma protein binding rate of warfarin significantly (P < .01). The results mean that HEI can potentiate the anticoagulant response of warfarin through both pharmacodynamics and pharmacokinetics.

Efficacy and safety of NOAC versus warfarin in AF patients with left atrial enlargement.

BACKGROUND: Little is known about the effects of anticoagulation in patients with atrial fibrillation (AF) and left atrial enlargement (LAE). METHODS: Data of patients with AF were retrieved from Chang Gung Research Database during 2007-2016. We excluded patients who were not using oral anticoagulants, used anticoagulants for <30 days, used ≥2 agents concomitantly or switched anticoagulants, had left atrial diameter missing from their data, were aged <65, had received valve surgeries, had mitral stenosis, or had a history of cancer. The primary outcomes were ischemic stroke (IS)/systemic embolism (SE), major bleeding, and death from any cause. RESULTS: We identified 40,777 patients who received a diagnosis of AF. After the exclusion criteria were applied, 6,445 patients remained, 4,922 with LAE, and they were followed up for 2.4 ±1.9 years. The mean age of the patients was 77.32 ± 0.18 in the NOAC group and 76.58 ± 6.91 in the warfarin group (p < 0.0001); 48.24% of patients in the NOAC group and 46.98% of patients in the warfarin group were men (p > 0.05). The mean CHA2DS2-VASc score was 3.26 ± 1.05 in the NOAC group and 3.07 ± 1.12 in the warfarin group (p < 0.0001). The mean HAS-BLED score was 3.87 ± 3.81 in the NOAC group and 3.86 ± 3.80 in the warfarin group (p > 0.05). Furthermore, the mean LA diameter was 4.75 ± 0.63 cm in the warfarin group and 4.79 ± 0.69 cm in the warfarin group (p > 0.05). Among patients with LAE, NOAC was associated with significantly reduced IS/SE events (CRR = 0.63, 95% CI = 0.52-0.77), no difference in major bleeding (CRR = 0.91, 95% CI = 0.78-1.05), and significantly reduced death from any cause (aHR = 0.65, 95% CI = 0.52-0.80) compared with warfarin. CONCLUSIONS: In elderly patients with AF and LAE, NOAC was associated with reduced IS/SE and death from any cause compared with warfarin, whereas no difference in major bleeding was observed between these treatments.

Warfarin Accelerates Aortic Calcification by Upregulating Senescence-Associated Secretory Phenotype Maker Expression.

Warfarin, a vitamin K antagonist (VKA), is known to promote arterial calcification (AC). In the present study, we conducted a case-cohort study within the Multi-Ethnic Study of Atherosclerosis (MESA); 6655 participants were included. From MESA data, we found that AC was related to both age and vitamin K; furthermore, the score of AC increased with SASP marker including interlukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) rising. Next, a total of 79 warfarin users in our center developed significantly more calcified coronary plaques as compared to non-VKA users. We investigated the role of warfarin in phosphate-induced AC in different ages by in vitro experimental study. Furthermore, dose-time-response of warfarin was positively correlated with AC score distribution and plasma levels of the SASP maker IL-6 among patients < 65 years, but not among patients ≥ 65 years. In addition, in vitro research suggested that warfarin treatment tended to deteriorate calcification in young VSMC at the early stage of calcification. Our results suggested that aging and warfarin-treatment were independently related to increased AC. Younger patients were more sensitive to warfarin-related AC than older patients, which was possibly due to accumulated warfarin-induced cellular senescence.

Multiplexed measurement of variant abundance and activity reveals VKOR topology, active site and human variant impact.

Vitamin K epoxide reductase (VKOR) drives the vitamin K cycle, activating vitamin K-dependent blood clotting factors. VKOR is also the target of the widely used anticoagulant drug, warfarin. Despite VKOR's pivotal role in coagulation, its structure and active site remain poorly understood. In addition, VKOR variants can cause vitamin K-dependent clotting factor deficiency or alter warfarin response. Here, we used multiplexed, sequencing-based assays to measure the effects of 2,695 VKOR missense variants on abundance and 697 variants on activity in cultured human cells. The large-scale functional data, along with an evolutionary coupling analysis, supports a four transmembrane domain topology, with variants in transmembrane domains exhibiting strongly deleterious effects on abundance and activity. Functionally constrained regions of the protein define the active site, and we find that, of four conserved cysteines putatively critical for function, only three are absolutely required. Finally, 25% of human VKOR missense variants show reduced abundance or activity, possibly conferring warfarin sensitivity or causing disease.

AntagomiR-29b inhibits vascular and valvular calcification and improves heart function in rats.

We aimed to investigate the role of the miR-29b and its effect on TGF-ß3 pathway in vascular and valvular calcification in a rat model of calcific aortic valve diseases (CAVD). A rat model of CAVD was established by administration of warfarin plus vitamin K. The expression levels of miR-29b, osteogenic markers and other genes were determined by qRT-PCR, Western blot and/or immunofluorescence and immunohistochemistry. The calcium content and alkaline phosphatase (ALP) activity were measured. The calcium content, ALP activity and osteogenic markers levels in calcified aorta and aortic valve were augmented compared to controls. The expression of miR-29b, p-Smad3, and Wnt3 and ß-catenin was significantly up-regulated, whereas TGF-ß3 was markedly down-regulated. However, compared with the CAVD model group, the calcium content and ALP activity in rats treated with antagomiR-29b were significantly decreased, and antagomiR-29b administration reversed the effects of CAVD model on the expression of miR-29b and osteogenic markers. Inhibition of miR-29b in CAVD rats prevented from vascular and valvular calcification and induced TGF-ß3 expression, suggesting that the miR-29b/TGF-ß3 axis may play a regulatory role in the pathogenesis of vascular and valvular calcification and could play a significant role in the treatment of CAVD and other cardiovascular diseases.