Early and late-onset preeclampsia: effects of DDAH2 polymorphisms on ADMA levels and association with DDAH2 haplotypes.

Objective: To examine whether the DDAH2 promoter polymorphisms -1415G/A (rs2272592), -1151A/C (rs805304) and -449G/C (rs805305), and their haplotypes, are associated with PE compared with normotensive pregnant women, and whether they affect ADMA levels in these groups. Methods: A total of 208 pregnant women were included in the study and classified as early-onset (N=57) or late-onset PE (N =49), and as normotensive pregnant women (N = 102). Results: Pregnant with early-onset PE carrying the GC and GG genotypes for the DDAH2 -449G/C polymorphism had increased ADMA levels (P=0.01). No association of DDAH2 polymorphisms with PE in single-locus analysis was found. However, the G-C-G haplotype was associated with the risk for late-onset PE. Conclusion: It is suggested that DDAH2 polymorphisms could affect ADMA levels in PE, and that DDAH2 haplotypes may affect the risk for PE.

Revealing novel biomarkers for diagnosing chronic kidney disease in pediatric patients.

Pediatric chronic kidney disease (CKD) is a clinical condition characterized by progressive renal function deterioration. CKD diagnosis is based on glomerular filtration rate, but its reliability is limited, especially at the early stages. New potential biomarkers (citrulline (CIT), symmetric dimethylarginine (SDMA), S-adenosylmethionine (SAM), n-butyrylcarnitine (nC4), cis-4-decenoylcarnitine, sphingosine-1-phosphate and bilirubin) in addition to creatinine (CNN) have been proposed for early diagnosis. To verify the clinical value of these biomarkers we performed a comprehensive targeted metabolomics study on a representative cohort of CKD and healthy pediatric patients. Sixty-seven children with CKD and forty-five healthy children have been enrolled in the study. Targeted metabolomics based on liquid chromatography-triple quadrupole mass spectrometry has been used for serum and plasma samples analysis. Univariate data analysis showed statistically significant differences (p < 0.05) in the concentration of CNN, CIT, SDMA, and nC4 among healthy and CKD pediatric patients. The predictive ability of the proposed biomarkers was also confirmed through specificity and sensitivity expressed in Receiver Operating Characteristic curves (AUC = 0.909). In the group of early CKD pediatric patients, AUC of 0.831 was obtained, improving the diagnostic reliability of CNN alone. Moreover, the models built on combined CIT, nC4, SDMA, and CNN allowed to distinguish CKD patients from healthy control regardless of blood matrix type (serum or plasma). Our data demonstrate potential biomarkers in the diagnosis of early CKD stages.

Aqueous preparation of arginyl-fructosyl-glucose (a maltose-arginine AC) and determination of Amadori compounds (ACs) in red ginseng by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).

Amadori compounds (ACs) are key Maillard intermediates in various foods after thermal processing, and are also important non-saponin components in red ginseng. Currently, due to the difficulty in obtaining AC standards, the determination of multiple ACs is limited and far from optimal. In this study, an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated. A green synthetic method was developed for arginyl-fructosyl-glucose (AFG), the major AC in red ginseng with potential health benefits. The UPLC-MS/MS method was then applied in identification and quantification of ACs in red ginseng samples, which showed for the first time that 12 other ACs also exist in red ginseng in addition to AFG and arginyl-fructose (total 98.88 % of all ACs). Contents of AFG and arginyl-fructose in whole red ginseng were 36.23 and 10.80 mg/g dry weight, respectively. Raw ginseng can be steamed and then dried whole to obtain whole red ginseng, or sliced before drying to obtain sliced red ginseng. Slicing before drying was found to reduce ACs content. Results of the present study will help to reveal the biological functions of red ginseng and related products associated with ACs and promote the standardization of red ginseng manufacture.

Symmetric dimethylarginine correlates with the urea, creatinine, potassium, and clinical scores in feline urethral obstructions.

BACKGROUND: A urethral obstruction (UO) is an emergency commonly observed in male cats, which can result in significant clinical and laboratory alterations, leading to complications and death. OBJECTIVES: This study aimed to correlate symmetric dimethylarginine (SDMA) with the urea, creatinine, potassium, and bicarbonate levels in cats with UO. In addition, the correlation between clinical score and time of obstruction was evaluated. METHODS: Thirty male cats were selected and allocated into a control group (CG, n = 13) and an obstruction group (OG, n = 17). The laboratory analyses were conducted before treatment (M0) and at different times after treatment (12 h [M12], 24 h [M24], and 48 h [M48]). Correlations were established between SDMA and creatinine, urea, bicarbonate, potassium, time of obstruction, and the clinical score. RESULTS: A strong correlation (r > 0.6) was observed between SDMA and creatinine, urea, and potassium in the OG. Furthermore, there was substantial agreement (kappa value) between SDMA and creatinine at M24. A higher clinical score was associated with a longer time of obstruction. In the OG, at M48, the SDMA and creatinine levels were 50% and 41.2% higher, respectively. CONCLUSIONS: A correlation was observed between SDMA and creatinine in obstructed cats, and significant agreement between these values was observed 24 h after the unblocking treatment. A correlation among SDMA, urea, and potassium was observed. Approximately 9% more cats continued to have elevated SDMA levels after 48 h of treatment compared to creatinine. This suggests a slightly lower sensitivity of the latter biomarker but does not exclude the possibility of congruent and normalized values after a longer evaluation period.

Arginase inhibitor reduces fungal dissemination in murine pulmonary cryptococcosis by promoting anti-cryptococcal immunity.

Elevation of arginase enzyme activity in the lung contributes to the pathogenesis of various chronic inflammatory diseases and infections. Inhibition of arginase expression and activity is able to alleviate those effects. Here, we investigated the immunomodulatory effect of arginase inhibitor in C. neoformans infection. In the pulmonary cryptococcosis model that was shown to recapitulate human infection, we found arginase expression was excessively induced in the lung during the late stage of infection. To inhibit the activity of arginase, we administered a specific arginase inhibitor, nor-NOHA, during C. neoformans infection. Inhibition of arginase reduced eosinophil infiltration and level of IL-13 secretion in the lungs. Whole lung transcriptome RNA-sequencing analysis revealed that treatment with nor-NOHA resulted in shifting the Th2-type gene expression patterns induced by C. neoformans infection to the Th1-type immune profile, with higher expression of cytokines Ifng, Il6, Tnfa, Csf3, chemokines Cxcl9 and Cxcl10 and transcription factor Stat1. More importantly, mice treated with arginase inhibitor had more infiltrating brain leukocytes and enhanced gene expression of Th1-associated cytokines and chemokines that are known to be essential for protection against C. neoformans infection. Inhibition of arginase dramatically attenuated spleen and brain infection, with improved survival. Taken together, these studies demonstrated that inhibiting arginase activity induced by C. neoformans infection can modulate host immune response by enhancing protective type-1 immune response during C. neoformans infection. The inhibition of arginase activity could be an immunomodulatory target to enhance protective anti-cryptococcal immune responses.

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.

Asymmetric dimethylarginine (ADMA) is associated with reduced myocardial mechano-energetic efficiency in hypertensive subjects.

BACKGROUND AND AIMS: Our prior study showed that endothelial dysfunction contributed to reduced myocardial mechano-energetics efficiency (MEEi) independently of several confounders. Reduced activity of endothelial nitric oxide synthase may be due to increased levels of the endogenous inhibitor asymmetric dimethylarginine (ADMA). The impact of ADMA on myocardial MEEi has not been determined yet. This study aims to investigate the association between plasma ADMA levels and MEEi in drug-naïve hypertensive individuals. METHODS AND RESULTS: 63 hypertensive individuals participating in the CATAnzaro MEtabolic RIsk factors (CATAMERI) study were included. All participants underwent to an echocardiogram for myocardial MEEi measurement. ADMA plasma concentrations were measured by high-performance liquid chromatography. A multivariate linear regression analysis was conducted to investigate the independent association between ADMA levels and MEEi. In a univariate analysis, ADMA levels were significantly associated with myocardial MEEi (r = 0.438; P < 0.001). In a multivariate regression analysis, plasma ADMA levels were associated to decreased myocardial MEEi (ß = 0.458, P < 0.001) independently of well-established cardiovascular risk factors including age, sex, BMI, waist circumference, smoking status, total cholesterol and HDL, triglycerides, glucose tolerance status, and HOMA-IR index of insulin resistance. CONCLUSIONS: ADMA may contribute to reduced myocardial MEEi by reducing nitric oxide bioavailability.

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.

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.

Serum symmetric dimethylarginine in older dogs: Reference interval and comparison of a gold standard method with the ELISA.

BACKGROUND: Serum symmetric dimethylarginine (SDMA) is used to screen for renal dysfunction in dogs. The gold standard technique for measuring SDMA, liquid chromatography-tandem mass spectrometry (LC-MS/MS) is not widely available. Age-specific reference intervals for SDMA in older dogs are lacking. OBJECTIVES: Prospective study in older dogs to validate a commercially available LC-MS/MS method for SDMA, compare SDMA concentrations with concentrations measured using ELISA and obtain a reference interval (RI) for older dogs using both methods. ANIMALS: Client-owned older dogs undergoing health screening. METHODS: The LC-MS/MS method was analytically validated (limit of detection, precision, and linearity). Serum was sent cooled overnight for ELISA or was frozen at -80°C until batch analysis using LC-MS/MS. Results of LC-MS/MS and ELISA were compared and RIs for older dogs were calculated according to international guidelines. RESULTS: The LC-MS/MS method showed good linearity (r2 = .99) and precision (coefficient of variation <10%), with a laboratory RI between 8.0 and 14.0 µg/dL. Paired measurements were available from 118 different dogs. Median SDMA concentration were 9.4 (range, 5.0-21.2) using LC-MS/MS and 12.0 (range, 5.0-22.0) µg/dL using ELISA. Both methods significantly differed with a mean difference of 2.2 µg/dL. The RI for older dogs for LC-MS/MS was 4.4-15.0 µg/dL, and for ELISA was 6.4-17.4 µg/dL. CONCLUSIONS AND CLINICAL IMPORTANCE: The ELISA provided significantly higher SDMA concentrations compared to the validated LC-MS/MS method, indicating the need for device- or assay-specific RI. The obtained age-specific RI for SDMA is considerably higher in older dogs compared to the general laboratory RI.

Asymmetric Dimethylarginine Enables Depolarizing Spikes and Vasospasm in Mesenteric and Coronary Resistance Arteries.

BACKGROUND: Increased vasoreactivity due to reduced endothelial NO bioavailability is an underlying feature of cardiovascular disease, including hypertension. In small resistance arteries, declining NO enhances vascular smooth muscle (VSM) reactivity partly by enabling rapid depolarizing Ca2+-based spikes that underlie vasospasm. The endogenous NO synthase inhibitor asymmetric dimethylarginine (ADMA) is metabolized by DDAH1 (dimethylarginine dimethylaminohydrolase 1) and elevated in cardiovascular disease. We hypothesized ADMA might enable VSM spikes and vasospasm by reducing NO bioavailability, which is opposed by DDAH1 activity and L-arginine. METHODS: Rat isolated small mesenteric arteries and myogenic rat-isolated intraseptal coronary arteries (RCA) were studied using myography, VSM intracellular recording, Ca2+ imaging, and DDAH1 immunolabeling. Exogenous ADMA was used to inhibit NO synthase and a selective DDAH1 inhibitor, NG-(2-methoxyethyl) arginine, to assess the functional impact of ADMA metabolism. RESULTS: ADMA enhanced rat-isolated small mesenteric arteries vasoreactivity to the α1-adrenoceptor agonist, phenylephrine by enabling T-type voltage-gated calcium channel-dependent depolarizing spikes. However, some endothelium-dependent NO-vasorelaxation remained, which was sensitive to DDAH1-inhibition with NG-(2-methoxyethyl) arginine. In myogenically active RCA, ADMA alone stimulated depolarizing Ca2+ spikes and marked vasoconstriction, while NO vasorelaxation was abolished. DDAH1 expression was greater in rat-isolated small mesenteric arteries endothelium compared with RCA, but low in VSM of both arteries. L-arginine prevented depolarizing spikes and protected NO-vasorelaxation in rat-isolated small mesenteric artery and RCA. CONCLUSIONS: ADMA increases VSM electrical excitability enhancing vasoreactivity. Endothelial DDAH1 reduces this effect, and low levels of DDAH1 in RCAs may render them susceptible to endothelial dysfunction contributing to vasospasm, changes opposed by L-arginine.

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.

N-acetylcysteine and Hydroxychloroquine Ameliorate ADMA-Induced Fetal Growth Restriction in Mice via Regulating Oxidative Stress and Autophagy.

Fetal growth restriction (FGR) seriously threatens perinatal health. The main cause of FGR is placental malperfusion, but the specific mechanism is still unclear, and there is no effective treatment for FGR. We constructed a FGR mouse model by adding exogenous asymmetric dimethylarginine (ADMA) through in vivo experiments and found that ADMA could cause placental dysplasia and induce the occurrence of FGR. Compared with the control group, reactive oxygen species (ROS) production in the placenta was increased in mice with FGR, and the expression of autophagy-related proteins p-AKT/AKT, p-mTOR/mTOR, and P62 was significantly decreased, while the expression of Beclin-1 and LC3-II was significantly increased in the FGR group. Furthermore, ADMA had a favorable effect in promoting the formation of autophagosomes. Hydroxychloroquine (HCQ) and N-acetylcysteine (NAC) improved ADMA-induced disorders of placental development and alleviated ADMA-induced FGR. This study found that ADMA could cause excessive autophagy of trophoblasts by increasing the level of oxidative stress, ultimately leading to the occurrence of FGR, and HCQ and NAC had therapeutic effects on ADMA-induced FGR.

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.

Early decrease of ionized calcium and static symmetric dimethylarginine concentration in a model of renal tubular necrosis in corn snakes (Pantherophis guttatus).

OBJECTIVE: To determine if plasma concentrations of symmetric dimethylarginine (SDMA), N-acetyl-beta-d-glucosaminidase (NAG), GGT, ALT, AST, lactate, total calcium, and ionized calcium (iCa) and the calcium:phosphorus ratio are clinically relevant biomarkers to detect early stages of tubular lesions in snakes. ANIMALS: 6 adult corn snakes (Pantherophis guttatus). METHODS: Corn snakes were administered 11 injections of gentamicin at 50 mg/kg, SC, q 24 h in an experimental model of induced tubular necrosis. Plasma biochemistry and blood gas analyses were performed at baseline and after the 3rd and 11th injections. Parameters were compared between time points using a paired Wilcoxon test. In 3 individuals, renal biopsies were collected at baseline before starting injections and at the 3rd and 11th injections, while renal tissue samples were procured after euthanasia in all individuals. RESULTS: Renal proximal and distal tubular necrosis and hepatic steatosis were present in all individuals at necropsy. Compared to baseline, decreased blood concentrations of lactate, ionized calcium, and total calcium and a decreased calcium:phosphorus ratio were noted. A significant decrease of lactate and ionized calcium was observed after 3 days. Conversely, no changes in SDMA, NAG, ALT, AST, GGT, and sodium were detected. CLINICAL RELEVANCE: Ionized calcium and lactate concentrations were the earliest parameters to decrease compared to baseline values in this experimental model. While SDMA is a sensitive indicator of renal disease in mammals, this biomarker did not increase in a model of induced acute tubular necrosis in corn snakes.

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.

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.

Factor XI and coagulation. Factor XI inhibitors - antithrombotic perspectives.

Factor XI is a zymogen with an important role in the coagulation cascade. It is activated by FXII, thrombin and or it can be autoactivated. It has a prothrombotic effect after being activated by thrombin, but also through its antifibrinolytic action, stabilizing the formed clot. Hereditary deficiency of FXI causes haemophilia C - a disease manifested by an usually provoked, small to moderate mucosal bleeding. People with severe FXI deficiency have a low risk of thrombotic events. Conversely, increased FXI values have been found to be associated with increased risk of venous thromboembolism and ischemic stroke. Lowering serum FXI levels has become a treatment target for the prevention of thrombotic events. New pharmacological agents - FXI inhibitors - have been investigated in phase II clinical trials, with promising results in terms of efficacy and safety in the prevention of thrombotic events. FXI inhibitors are emerging as new anticoagulant agents with broad indication prospects beyond direct oral anticoagulants and vitamin K antagonists.

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.