Association between 24-hour blood pressure parameters and 90-day functional outcome in acute ischemic stroke patients with early anticoagulation.

This study aimed to examine the relationship between blood pressure (BP) and blood pressure variability (BPV) during the first 24 hours from admission with 90-day functional outcomes in acute ischemic stroke (AIS) patients whose onset within 24 hours and receiving early argatroban treatment. The study recruited 214 AIS patients. BP was monitored using a cuff at 1-hour fixed intervals, and BP/BPV parameters [standard deviation (SD), coefficient of variation (CV), successive variation (SV), and average real variability (ARV)] were collected. Age, the National Institutes of Health Stroke Scale (NIHSS) score at admission, previous history of diabetes mellitus (DM), and infarction site (located in anterior circulation) were identified as independent factors affecting 90-day outcomes in multiple logistic regression. After adjusting for confounding variables, association between BP/BPV and 90-day modified Rankin Scale (mRS) was assessed using logistic regression models. In model 1 (adjusted for age and NIHSS score at admission), mean-systolic blood pressure (SBP) showed association with 90-day outcomes [1.068 (1.008, 1.131), P = .025]. In model 2 (adjusted for age, NIHSS score at admission, previous history of DM), mean-SBP [1.061 (1.001, 1.123), P = .045] and max-SBP [0.951 (0.906, 0.998), P = .040] showed relatively weak association with outcomes. In model 3 [adjusted for age, NIHSS score at admission, previous history of DM, infarct site (located in anterior circulation)], all BP values were not related with outcomes, meanwhile, none of the BPV parameters calculated from SBP, diastolic blood pressure and mean arterial pressure showed association with 90-day outcomes. Future prospective studies are required to assess the relationship between early BP/BPV parameters with 90-day outcomes and further clarify the reference values for BP parameters. This is important for effective BP/BPV management and improved patient prognosis.

A NAC triad modulates plant immunity by negatively regulating N-hydroxy pipecolic acid biosynthesis.

N-hydroxy pipecolic acid (NHP) plays an important role in plant immunity. In contrast to its biosynthesis, our current knowledge with respect to the transcriptional regulation of the NHP pathway is limited. This study commences with the engineering of Arabidopsis plants that constitutively produce high NHP levels and display enhanced immunity. Label-free proteomics reveals a NAC-type transcription factor (NAC90) that is strongly induced in these plants. We find that NAC90 is a target gene of SAR DEFICIENT 1 (SARD1) and induced by pathogen, salicylic acid (SA), and NHP. NAC90 knockout mutants exhibit constitutive immune activation, earlier senescence, higher levels of NHP and SA, as well as increased expression of NHP and SA biosynthetic genes. In contrast, NAC90 overexpression lines are compromised in disease resistance and accumulated reduced levels of NHP and SA. NAC90 could interact with NAC61 and NAC36 which are also induced by pathogen, SA, and NHP. We next discover that this protein triad directly represses expression of the NHP and SA biosynthetic genes AGD2-LIKE DEFENSE RESPONSE PROTEIN 1 (ALD1), FLAVIN MONOOXYGENASE 1 (FMO1), and ISOCHORISMATE SYNTHASE 1 (ICS1). Constitutive immune response in nac90 is abolished once blocking NHP biosynthesis in the fmo1 background, signifying that NAC90 negative regulation of immunity is mediated via NHP biosynthesis. Our findings expand the currently documented NHP regulatory network suggesting a model that together with NHP glycosylation, NAC repressors take part in a 'gas-and-brake' transcriptional mechanism to control NHP production and the plant growth and defense trade-off.

Impact of C-reactive Protein on Anticoagulation Monitoring in Extracorporeal Membrane Oxygenation.

OBJECTIVE: To evaluate the impact of inflammation on anticoagulation monitoring for patients supported with extracorporeal membrane oxygenation (ECMO). DESIGN: Prospective single-center cohort study. SETTING: University-affiliated tertiary care academic medical center. PARTICIPANTS: Adult venovenous and venoarterial ECMO patients anticoagulated with heparin/ MEASUREMENTS AND MAIN RESULTS: C-Reactive protein (CRP) was used as a surrogate for overall inflammation. The relationship between CRP and the partial thromboplastin time (PTT, seconds) was evaluated using a CRP-insensitive PTT assay (PTT-CRP) in addition to measurement using a routine PTT assay. Data from 30 patients anticoagulated with heparin over 371 ECMO days was included. CRP levels (mg/dL) were significantly elevated (median, 17.2; interquartile range [IQR], 9.2-26.1) and 93% of patients had a CRP of ≥5. The median PTT (median 58.9; IQR, 46.9-73.3) was prolonged by 11.3 seconds compared with simultaneously measured PTT-CRP (median, 47.6; IQR, 40.1-55.5; p < 0.001). The difference between PTT and PTT-CRP generally increased with CRP elevation from 2.7 for a CRP of <5.0 to 13.0 for a CRP between 5 and 10, 17.7 for a CRP between 10 and 15, and 15.1 for a CRP of >15 (p < 0.001). In a subgroup of patients, heparin was transitioned to argatroban, and a similar effect was observed (median PTT, 62.1 seconds [IQR, 53.0-78.5 seconds] vs median PTT-CRP, 47.6 seconds [IQR, 41.3-57.7 seconds]; p < 0.001). CONCLUSIONS: Elevations in CRP are common during ECMO and can falsely prolong PTT measured by commonly used assays. The discrepancy due to CRP-interference is important clinically given narrow PTT targets and may contribute to hematological complications.

Aflatoxin B1-induced liver pyroptosis is mediated by disturbing the gut microbial metabolites: The roles of pipecolic acid and norepinephrine.

The disturbed gut microbiota is a key factor in activating the aflatoxin B1 (AFB1)-induced liver pyroptosis by promoting inflammatory hepatic injury; however, the pathogen associated molecular pattern (PAMP) from disturbed gut microbiota and its mechanism in activating liver pyroptosis remain undefined. By transplanting AFB1-originated fecal microbiota and sterile fecal microbial metabolites filtrate, we determined the association of PAMP in AFB1-induced liver pyroptosis. Notably, AFB1-originated sterile fecal microbial metabolites filtrate were more active in triggering liver pyroptosis in mice, as compared to parental fecal microbiota. This result supported a critical role of the metabolic homeostasis of gut microbiota in AFB1-induced liver pyroptosis, rather than an injurious response to direct exposure of AFB1 in liver. Among the gut-microbial metabolites, pipecolic acid and norepinephrine were proposed to bind TLR4 and NLRP3, the upstream proteins of pyroptosis signaling pathway. Besides, the activations of TLR4 and NLRP3 were linearly correlated with the concentrations of pipecolic acid and norepinephrine in the serum of mice. In silenced expression of TLR4 and NLRP3 in HepG2 cells, pipecolic acid or norepinephrine did not able to activate hepatocyte pyroptosis. These results demonstrated the necessity of gut microbial metabolism in sustaining liver homeostasis, as well as the potential to provide new insights into targeted intervention for AFB1 hepatotoxicity.

Clinical and economic implications of false-positive heparin-induced thrombocytopenia immunoassays: utility of the 4T score.

Heparin-induced thrombocytopenia (HIT) is a prothrombotic condition induced by platelet-activating IgG antibodies that recognize PF4/heparin complexes. Diagnosis of HIT relies on enzyme immunologic assays (EIAs) and functional assays [serotonin release assay (SRA)]. Our institution uses a latex immunoturbidimetric assay (LIA), which has shown a positive-predictive value (PPV) of 55.6%, and a negative-predictive value (NPV) of 99.7%. The low PPV of EIAs/LIAs, in combination with the clinical delay in obtaining results of a SRA, commonly leads to a false-positive diagnosis of HIT and inappropriate treatment. We performed a single-institution retrospective study at a large tertiary center to assess patient management decisions and economic costs following a false-positive HIT (LIA) test. This study found an 89.5% incidence of false-positive HIT (LIA) tests. 97.4% of patients underwent anticoagulation changes. 69.6% of patients were switched to argatroban. Of patients with a false-positive HIT immunoassay (LIA), 42 (40.7%) patients were on a prophylactic dose of anticoagulation at the time of HIT (LIA) positivity, of which 22 (52.4%) were switched to full anticoagulation with either argatroban or fondaparinux. Of the 22 patients switched to full anticoagulation, 15 (68%) had low-probability 4T scores. Seven (8.8%) of patients had bleeding events after HIT (LIA) positivity. All seven patients were switched to argatroban from a full-dose heparin anticoagulation. Five of the seven patients were considered major bleeds. Utilization of argatroban incurred substantial costs, estimated at approximately $73 000 for false-positive HIT cases. False-positive HIT (LIA) tests contribute to unwarranted anticoagulation changes, increased bleeding risks, and substantial healthcare costs. Incorporating the 4T score into diagnostic algorithms may help mitigate these risks by guiding appropriate clinical decisions. Future research should focus on refining diagnostic approaches and standardizing management strategies to improve patient outcomes and cost-effectiveness in HIT diagnosis and management.

SA and NHP glucosyltransferase UGT76B1 affects plant defense in both SID2- and NPR1-dependent and independent manner.

KEY MESSAGE: The small-molecule glucosyltransferase loss-of-function mutant ugt76b1 exhibits both SID2- or NPR1-dependent and independent facets of enhanced plant immunity, whereupon FMO1 is required for the SID2 and NPR1 independence. The small-molecule glucosyltransferase UGT76B1 inactivates salicylic acid (SA), isoleucic acid (ILA), and N-hydroxypipecolic acid (NHP). ugt76b1 loss-of-function plants manifest an enhanced defense status. Thus, we were interested how UGT76B1 genetically integrates in defense pathways and whether all impacts depend on SA and NHP. We study the integration of UGT76B1 by transcriptome analyses of ugt76b1. The comparison of transcripts altered by the loss of UGT76B1 with public transcriptome data reveals both SA-responsive, ISOCHORISMATE SYNTHASE 1/SALICYLIC ACID INDUCTION DEFICIENT 2 (ICS1/SID2)- and NON EXPRESSOR OF PR GENES 1 (NPR1)-dependent, consistent with the role of UGT76B1 in glucosylating SA, and SA-non-responsive, SID2/NPR1-independent genes. We also discovered that UGT76B1 impacts on a group of genes showing non-SA-responsiveness and regulation by infections independent from SID2/NPR1. Enhanced resistance of ugt76b1 against Pseudomonas syringae is partially independent from SID2 and NPR1. In contrast, the ugt76b1-activated resistance is completely dependent on FMO1 encoding the NHP-synthesizing FLAVIN-DEPENDENT MONOOXYGENASE 1). Moreover, FMO1 ranks top among the ugt76b1-induced SID2- and NPR1-independent pathogen responsive genes, suggesting that FMO1 determines the SID2- and NPR1-independent effect of ugt76b1. Furthermore, the genetic study revealed that FMO1, ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), SID2, and NPR1 are required for the SA-JA crosstalk and senescence development of ugt76b1, indicating that EDS1 and FMO1 have a similar effect like stress-induced SA biosynthesis (SID2) or the key SA signaling regulator NPR1. Thus, UGT76B1 influences both SID2/NPR1-dependent and independent plant immunity, and the SID2/NPR1 independence is relying on FMO1 and its product NHP, another substrate of UGT76B1.

Anticoagulation with argatroban using hemoclot™ targets is safe and effective in CARDS patients receiving venovenous extracorporeal membrane oxygenation: An exploratory bi-centric cohort study.

Direct thrombin inhibitors, including argatroban, are increasingly used for anticoagulation during venovenous extracorporeal membrane oxygenation (VV ECMO). In many centers activated partial thromboplastin time (aPTT) is used for monitoring, but it can be affected by several confounders. The aim of this study was to evaluate the safety and efficacy of anticoagulation with argatroban titrated according to diluted thrombin time targets (hemoclot™ assay) compared to anti-Xa guided anticoagulation with unfractionated heparin (UFH). METHODS: This cohort study included adults at two tertiary care centers who required VV ECMO for severe COVID-19-related acute respiratory distress syndrome (CARDS). Patients received center-dependent argatroban or UFH for anticoagulation during ECMO. Argatroban was guided following a hemoclot™ target range of 0.4-0.6 µg/ml. UFH was guided by anti-factor Xa (antiXa) levels (0.2-0.3 IU/ml). The primary outcome was safety of argatroban compared to UFH, assessed by time to first clinically relevant bleeding event or death during ECMO. Secondary outcomes included efficacy (time to thromboembolism) and feasibility (proportion of anticoagulation targets within range). RESULTS: From 2019 to 2021 57 patients were included in the study with 27 patients (47 %) receiving argatroban and 30 patients (53 %) receiving UFH. The time to the first clinically relevant bleeding or death during ECMO was similar between groups (HR (argatroban vs. UFH): 1.012, 95 % CI 0.44-2.35, p = 0.978). Argatroban was associated with a decreased risk for thromboembolism compared to UFH (HR 0.494 (95 % CI 0.26-0.95; p = 0.034)). The overall proportion of anticoagulation within target ranges was not different between groups (46 % (23-54 %) vs. 46 % (37 %-57 %), p = 0.45). CONCLUSION: Anticoagulation with argatroban according to hemoclot™ targets (0.4-0.6 µg/ml) compared to antiXa guided UFH (0.2-0.3 IU/ml) is safe and may prolong thromboembolism-free time in patients with severe ARDS requiring VV ECMO.

Can the combination of antiplatelet or alteplase thrombolytic therapy with argatroban benefit patients suffering from acute stroke? a systematic review, meta-analysis, and meta-regression.

BACKGROUND: The effectiveness of administering argatroban as a treatment approach following antiplatelet therapy or alteplase thrombolytic therapy in patients with acute stroke is presently uncertain. However, it is important to highlight the potential benefits of combining this medication with known thrombolytics or antiplatelet therapy. One notable advantage of argatroban is its short half-life, which helps minimize excessive anticoagulation and risk of bleeding complications in inadvertent cases of hemorrhagic stroke. By conducting a meticulous review and meta-analysis, we aim to further explore the common use of argatroban and examine the plausible advantages of combining this medication with established thrombolytic and antiplatelet therapies. METHOD: In this study, we performed a rigorous and methodical search for both randomized controlled trials and retrospective analyses. Our main objective was to analyze the impact of argatroban on the occurrence of hemorrhagic events and the mRS scores of 0-2. We utilized a meta-analysis to assess the relative risk (RR) associated with using argatroban versus not using it. RESULTS: In this study, we analyzed data from 11 different studies, encompassing a total of 8,635 patients. Out of these patients, 3999(46.3%) received argatroban treatment while the remaining 4636(53.7%)did not. The primary outcome of 90-day functional independence (modified Rankin scale (mRS) score≤2) showed that the risk ratio (RR) for patients using argatroban after alteplase thrombolytic therapy compared to those not using argatroban was(RR, 1.00 ([95% CI, 0.92-1.09]; P = 0.97), indicating no statistical significance. However, for patients using argatroban after antiplatelet therapy, was (RR,1.09 [95% CI, 1.04-1.14]; P = 0.0001), which was statistically significant. In terms of hemorrhagic events, the RR for patients using argatroban compared to those not using argatroban was (RR,1.08 [95% CI, 0.88-1.33]; P = 0.46), indicating no statistical significance. CONCLUSION: The results of this study suggest that further research into combination therapy with argatroban and antiplatelet agents may be warranted, however more rigorous RCTs are needed to definitively evaluate the effects of combination treatment.

Precursor-directed biosynthesis and biological activity of tripropeptin Cpip, a new tripropeptin C analog containing pipecolic acid.

Tripropeptin C, a non-ribosomal cyclic lipopeptide containing three proline residues, exhibits excellent efficacy in the mouse-methicillin-resistant Staphylococcus aureus septicemia model. Since tripropeptins contain L-prolyl-D-proline and, as a result, are known to form a hairpin structure in proteins, it was of interest to determine whether this substructure contributes to their antibacterial activity. In this study, prolines in tripropeptin C were replaced with pipecolic acid(s) using precursor-directed biosynthesis. Only a new tripropeptin analog, tripropeptin Cpip, which has one L-pipecolic acid in place of L-proline, was isolated. The in vitro antimicrobial activity of the new analog was approximately two to four times weaker activity against Gram-positive bacteria, including drug-resistant species, compared with that of tripropeptin C. These results suggest that the L-prolyl-D-proline substructure plays an important role in the observed potency of tripropeptins.

Argatroban in Patients With Acute Ischemic Stroke With Early Neurological Deterioration: A Randomized Clinical Trial.

Importance: The effect of argatroban in patients with acute ischemic stroke (AIS) and early neurological deterioration (END) is unknown. Objective: To assess the efficacy of argatroban for END in AIS. Design, Setting, and Participants: This open-label, blinded-end point, randomized clinical trial was conducted from April 4, 2020, through July 31, 2022. The date of final follow-up was October 31, 2022. This was a multicenter trial. Eligible patients were adults with AIS who experienced END, which was defined as an increase of 2 or more points on the National Institutes of Health Stroke Scale within 48 hours from symptom onset. Patients who withdrew consent, experienced duplicate randomization, or were lost to follow-up were excluded from the study. Interventions: Patients were randomly assigned to the argatroban group and control group within 48 hours of symptom onset. Both groups received standard therapy based on guidelines, including oral mono or dual antiplatelet therapy. The argatroban group received intravenous argatroban for 7 days (continuous infusion at a dose of 60 mg per day for 2 days, followed by 20 mg per day for 5 days) in addition to standard therapy. Main Outcome and Measure: The primary end point was good functional outcome at 90 days, defined as a modified Rankin Scale score of 0 to 3. Results: A total of 628 patients (mean [SD] age, 65 [11.9] years; 400 male [63.7%]) were included in this study (argatroban group, 314 [50%] and control group, 314 [50%]). Of these, 18 withdrew consent, 1 had duplicate randomization, and 8 were lost to follow-up. A total of 601 patients with stroke were included in the intention-to-treat analysis. Finally, 564 patients were included in the per-protocol analysis as 6 participants in the argatroban group and 31 participants in the control group did not follow the complete protocol. The number of patients with good functional outcome at 90 days was 240 (80.5%) in the argatroban group and 222 (73.3%) in the control group (risk difference, 7.2%; 95% CI, 0.6%-14.0%; risk ratio, 1.10; 95% CI, 1.01-1.20; P = .04). The proportion of symptomatic intracranial hemorrhage was 3 of 317 (0.9%) in the argatroban group and 2 of 272 (0.7%) in the control group (P = .78). Conclusions and Relevance: Among patients with AIS with END, treatment with argatroban and antiplatelet therapy resulted in a better functional outcome at 90 days. This trial provided evidence to support the use of argatroban in reducing disability for patients with END. Trial Registration: ClinicalTrials.gov Identifier: NCT04275180.

Efficacy and safety of argatroban in the management of acute ischemic stroke: A systematic literature review and meta-analysis.

BACKGROUND: Acute ischemic stroke (AIS) is a leading cause of death and disability. AIS is caused by an embolus or thrombus that restricts blood flow to the brain tissue. Despite intravenous thrombolysis and endovascular thrombectomy, a substantial number of patients do not achieve effective reperfusion. Argatroban, a direct thrombin inhibitor, can potentially improve neurological outcomes in AIS patients. However, there are conflicting results in the medical literature regarding the efficacy and safety of argatroban in this context. OBJECTIVE: This study aims to evaluate the efficacy and safety of argatroban as monotherapy or adjunct therapy for acute ischemic stroke. METHODS: Five major databases (PubMed, Embase, Scopus, Web of Science, and Cochrane Library) were searched for randomized controlled trials (RCTs) that compared the efficacy and safety of using argatroban alone or in combination with recombinant tissue plasminogen activator (r-TPA) in the management protocol of the AIS. We used Review Manager Software (RevMan 5.4.1) for data analysis. RESULTS: We included 1393 patients from eight RCTs (of them, 726 were treated with argatroban alone or combined with r-TPA, while 667 received the placebo, standard therapy (standard treatments based on current guidelines including antihypertensive, antiplatelet agents, and statins) or endovascular r-TPA). Neither argatroban vs control nor argatroban with r-TPA vs r-TPA showed significant difference regarding the activity in daily living; (SMD= 1.69, 95% CI [-0.23, 3.61]; p = 0.09), (SMD= 0.99, 95% CI [-0.88, 2.86]; p = 0.30), respectively. Also, there was no significant difference in the National Institutes of Health Stroke Scale (NIHSS) score at seven days, the number of patients achieving modified Rankin Scale (mRS) of 0-1 or 0-2 at 90 days (p > 0.05). Argatroban did not significantly increase the risk of adverse events or symptomatic intracranial hemorrhage (ICH), or major systemic bleeding compared to control or r-TPA (p > 0.05) CONCLUSIONS: Argatroban does not demonstrate superior efficacy compared to placebo or standard therapy in terms of ADL, NIHSS and mRS outcomes. Importantly, argatroban does not significantly increase the incidence of adverse events, including symptomatic ICH and systemic bleeding.

Argatroban Use in Pediatric Patients Supported by Paracorporeal Ventricular Assist Devices.

Direct thrombin inhibitor (DTI) use has been associated with decreased stroke and death rates in children on ventricular assist devices (VADs). Most information about DTI use for children on VADs has focused on bivalirudin with limited data on argatroban. We hypothesized that, compared to unfractionated heparin (UFH), argatroban would be associated with decreased bleeding, stroke, and death rates in children on VADs. We retrospectively collected data from patients <18 years old on paracorporeal VADs at Children's Wisconsin between January 1, 2010 and July 1, 2021. We divided patients into cohorts based on anticoagulation strategy with heparin or argatroban. Definitions of bleeding and neurologic events were the same as in other published reports on this population. We compared categorical variables with the χ 2 or Fisher's exact test, and continuous variables with the Mann-Whitney U test. Nineteen children were anticoagulated with argatroban, and 16 with heparin. Demographics between groups were not significantly different. Stroke, bleeding, and death rates did not differ between patients treated with UFH versus argatroban. The study population was complex with a high rate of extracorporeal membrane oxygenation (ECMO) use before VAD support, which likely impacted our findings. Our study does not support argatroban as a superior alternative anticoagulant compared to UFH in children requiring VADs.

Association of Argatroban Dose With Coagulation Laboratory Test in Patients on Extracorporeal Membrane Oxygenation: Activated Clotting Time vs Activated Partial Thromboplastin Time.

BACKGROUND: Only some studies have directly compared and analyzed the roles of activated partial thromboplastin time (aPTT) and activated clotting time (ACT) in coagulation monitoring during argatroban administration. OBJECTIVES: This study aims to assess the correlation of argatroban dose with ACT and aPTT values and to identify the optimal coagulation test for argatroban dose adjustment. METHODS: We evaluated 55 patients on extracorporeal membrane oxygenation (ECMO) who received argatroban for more than 72 hours. The correlation between argatroban dose and aPTT and ACT values was evaluated. To compare argatroban dose and bleeding events according to liver dysfunction, the patients were divided into 2 groups based on alanine aminotransferase and total bilirubin. RESULTS: Among the 55 patients, a total of 459 doses and coagulation tests were evaluated. The aPTT and ACT values showed a weak correlation with argatroban dose, with the Pearson correlation coefficients of 0.261 (P < 0.001) and 0.194 (P = 0.001), respectively. The agreement between the target 150 to 180 seconds for ACT and 55 to 75 seconds for aPTT was observed in 140 patients (46.1%). Twenty-four patients (43.6%) had liver dysfunction when they started argatroban. The median argatroban dose was lower in the liver dysfunction group than in the control group (0.094 mcg/kg/min vs 0.169 mcg/kg/min, P = 0.020). Difference was not observed between the 2 groups in the amount of red blood cell (0.47 vs 0.43 pack, P = 0.909) and platelet (0.60 vs 0.08 pack, P = 0.079) transfusion per day. CONCLUSION AND RELEVANCE: A weak correlation was observed between argatroban dose and the aPTT and ACT values. However, the agreement between aPTT and ACT was only 46.1% regarding the scope of target range. Further research is necessary to determine how to assess the optimal argatroban dose for patients administered argatroban while undergoing ECMO at the intensive care unit.

Head-to-head ex vivo comparison of clinically used direct anticoagulant drugs.

An imbalance in coagulation is associated with cardiovascular events. For prevention and treatment, anticoagulants, currently mainly xabans and gatrans, are used. The purpose of the present study was to provide a head-to-head comparison since there are no studies directly evaluating these novel anticoagulants. An additional aim was to find whether selected anthropological and biochemical factors can affect their anticoagulant properties as they are used in fixed doses. In this cross-sectional study, blood from 50 generally healthy donors was collected, and coagulation responses to dabigatran, argatroban, rivaroxaban, and apixaban, at a concentration of 1 µM, were analyzed. Heparin was used as a positive control. Prothrombin time (PT) expressed as international normalized ratio (INR) and activated partial thromboplastin time (aPTT) were measured and compared. Rivaroxaban was the most active according to PT/INR while argatroban according to aPTT. The ex vivo anticoagulant effect measured by INR correlated inversely with body mass index (BMI) in all four anticoagulants tested. Shortening of aPTT was associated with higher cholesterol and triglyceride levels. No sex-related differences were observed in response to the anticoagulant treatments. As this was an ex vivo study and pharmacokinetic factors were not included, the influence of BMI is of high therapeutic importance.

Direct thrombin inhibitors fail to reverse the negative effects of heparin on lung growth and function after murine left pneumonectomy.

Neonates with congenital diaphragmatic hernia (CDH) frequently require cardiopulmonary bypass and systemic anticoagulation. We previously demonstrated that even subtherapeutic heparin impairs lung growth and function in a murine model of compensatory lung growth (CLG). The direct thrombin inhibitors (DTIs) bivalirudin and argatroban preserved growth in this model. Although DTIs are increasingly used for systemic anticoagulation clinically, patients with CDH may still receive heparin. In this experiment, lung endothelial cell proliferation was assessed following treatment with heparin-alone or mixed with increasing concentrations of bivalirudin or argatroban. The effects of subtherapeutic heparin with or without DTIs in the CLG model were also investigated. C57BL/6J mice underwent left pneumonectomy and subcutaneous implantation of osmotic pumps. Pumps were preloaded with normal saline, bivalirudin, or argatroban; treated animals received daily intraperitoneal low-dose heparin. In vitro, heparin-alone decreased endothelial cell proliferation and increased apoptosis. The effect of heparin on proliferation, but not apoptosis, was reversed by the addition of bivalirudin and argatroban. In vivo, low-dose heparin decreased lung volume compared with saline-treated controls. All three groups that received heparin demonstrated decreased lung function on pulmonary function testing and impaired exercise performance on treadmill tolerance testing. These findings correlated with decreases in alveolarization, vascularization, angiogenic signaling, and gene expression in the heparin-exposed groups. Together, these data suggest that bivalirudin and argatroban fail to reverse the inhibitory effects of subtherapeutic heparin on lung growth and function. Clinical studies on the impact of low-dose heparin with DTIs on CDH outcomes are warranted.NEW & NOTEWORTHY Infants with pulmonary hypoplasia frequently require cardiopulmonary bypass and systemic anticoagulation. We investigate the effects of simultaneous exposure to heparin and direct thrombin inhibitors (DTIs) on lung growth and pulmonary function in a murine model of compensatory lung growth (CGL). Our data suggest that DTIs fail to reverse the inhibitory effects of subtherapeutic heparin on lung growth and function. Clinical studies on the impact of heparin with DTIs on clinical outcomes are thus warranted.

Epigenetic regulation of N-hydroxypipecolic acid biosynthesis by the AIPP3-PHD2-CPL2 complex.

N-Hydroxypipecolic acid (NHP) is a signaling molecule crucial for systemic acquired resistance (SAR), a systemic immune response in plants that provides long-lasting and broad-spectrum protection against secondary pathogen infections. To identify negative regulators of NHP biosynthesis, we performed a forward genetic screen to search for mutants with elevated expression of the NHP biosynthesis gene FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1). Analysis of two constitutive expression of FMO1 (cef) and one induced expression of FMO1 (ief) mutants revealed that the AIPP3-PHD2-CPL2 protein complex, which is involved in the recognition of the histone modification H3K27me3 and transcriptional repression, contributes to the negative regulation of FMO1 expression and NHP biosynthesis. Our study suggests that epigenetic regulation plays a crucial role in controlling FMO1 expression and NHP levels in plants.

Transcriptomic and genetic approaches reveal that the pipecolate biosynthesis pathway simultaneously regulates tomato fruit ripening and quality.

Pipecolic acid (Pip) and N-hydroxypipecolic acid (NHP) have been found to accumulate during the ripening of multiple types of fruits; however, the function and mechanism of pipecolate pathway in fruits remain unclear. Here study was conducted on fruits produced by the model plant tomato, wherein the NHP biosynthesis-related genes, Slald1 and Slfmo1, were mutated. The results showed that the fruits of both the Slald1 and the Slfmo1 mutants exhibited a delayed onset of ripening, decreased fruit size, nutrition and flavor. Exogenous treatment with Pip and NHP promoted fruit ripening and improved fruit quality. Transcriptomic analysis combined with weighted gene co-expression network analysis revealed that the genes involved in the biosynthesis of amino acids, carbon metabolism, photosynthesis, starch and sucrose metabolism, flavonoid biosynthesis, and plant hormone signal transduction were affected by SlFMO1 gene mutation. Transcription factor prediction analysis revealed that the NAC and AP2/ERF-ERF family members are notably involved in the regulation pathway. Overall, our results suggest that the pipecolate biosynthesis pathway is involved in the simultaneous regulation of fruit ripening and quality and indicate that a regulatory mechanism at the transcriptional level exists. However, possible roles of endogenously synthesized Pip and NHP in these processes remain to be determined. The biosynthesis pathway genes SlALD1 and SlFMO1 may be potential breeding targets for promoting fruit ripening and improving fruit quality with concomitant yield increases.