Inhibitor Plasminogen Activator Research Articles

Cathepsin K deficiency prevented stress-related thrombosis in a mouse FeCl3 model

BackgroundExposure to chronic psychological stress (CPS) is a risk factor for thrombotic cardiocerebrovascular diseases (CCVDs). The expression and activity of the cysteine cathepsin K (CTSK) are upregulated in stressed cardiovascular tissues, and we investigated whether CTSK is involved in chronic stress-related thrombosis, focusing on stress serum-induced endothelial apoptosis.Methods and resultsEight-week-old wild-type male mice (CTSK+/+) randomly divided to non-stress and 3-week restraint stress groups received a left carotid artery iron chloride3 (FeCl3)-induced thrombosis injury for biological and morphological evaluations at specific timepoints. On day 21 post-stress/injury, the stress had enhanced the arterial thrombi weights and lengths, in addition to harmful alterations of plasma ADAMTS13, von Willebrand factor, and plasminogen activation inhibitor-1, plus injured-artery endothelial loss and CTSK protein/mRNA expression. The stressed CTSK+/+ mice had increased levels of injured arterial cleaved Notch1, Hes1, cleaved caspase8, matrix metalloproteinase-9/-2, angiotensin type 1 receptor, galactin3, p16IN4A, p22phox, gp91phox, intracellular adhesion molecule-1, TNF-α, MCP-1, and TLR-4 proteins and/or genes. Pharmacological and genetic inhibitions of CTSK ameliorated the stress-induced thrombus formation and the observed molecular and morphological changes. In cultured HUVECs, CTSK overexpression and silencing respectively increased and mitigated stressed-serum- and H2O2-induced apoptosis associated with apoptosis-related protein changes. Recombinant human CTSK degraded γ-secretase substrate in a dose-dependent manor and activated Notch1 and Hes1 expression upregulation.ConclusionsCTSK appeared to contribute to stress-related thrombosis in mice subjected to FeCl3 stress, possibly via the modulation of vascular inflammation, oxidative production and apoptosis, suggesting that CTSK could be an effective therapeutic target for CPS-related thrombotic events in patients with CCVDs.

Epigenetic and biological age acceleration in children with atopic dermatitis

BackgroundAtopic dermatitis is a chronic inflammatory skin disease resulting from the complex interplay of genetic and environmental factors, meriting exploration using temporally-dynamic biomarkers. DNA methylation-based algorithms have been trained to accurately estimate biological age, and deviation of predicted age from true age (epigenetic age acceleration) has been implicated in several inflammatory diseases, including asthma. ObjectiveTo determine the role of epigenetic and biological aging, telomere length, and epigenetically-inferred abundance of seven inflammatory biomarkers in atopic dermatitis. MethodsWe performed DNA methylation-based analyses in a pediatric atopic dermatitis cohort (n=24, mean age 2.56±0.28y) and age-matched healthy subjects (n=24, mean age 2.09±0.15y) derived from blood, using five validated algorithms that assess epigenetic (Horvath, Skin&Blood) and biological age (PhenoAge, GrimAge), telomere length (TelomereLength), and inflammatory biomarker levels. ResultsEpigenetic and biological age, but not telomere length, were accelerated in atopic dermatitis patients for four algorithms: Horvath (+0.88 years; 95%CI 0.33-1.4; p=2.3x10-3), Skin&Blood (+0.95 years; 95%CI 0.67-1.2; p=1.8x10-8), PhenoAge (+8.2 years; 95%CI 3.4-13.0; p=1.3x10-3), and GrimAge (+1.8 years 95%CI 0.22-3.3; p=0.026). Moreover, patients had increased levels of beta-2-microglobulin (+47,584.4 ng/ml; p=0.029), plasminogen activation inhibitor 1 (+3,432.9 ng/ml; p=1.1x10-5) and cystatin C (+31,691 ng/ml; p=4.0x10-5), while levels of tissue inhibitor metalloproteinase 1 (-370.7 ng/ml; p=7.5x10-4) were decreased versus healthy subjects. ConclusionDNA methylation changes associated with epigenetic and biological aging, and inflammatory proteins appear early in life in pediatric atopic dermatitis and may be relevant clinical biomarkers of pathophysiology.

Spontaneous reperfusion in STEMI: Its mechanisms and possible modulation.

Patients with transient ST-segment elevation myocardial infarction or spontaneous reperfusion, which occurs in approximately 20% of patients with ST-segment elevation myocardial infarction (STEMI), have smaller infarcts and more favorable clinical outcomes than patients without spontaneous reperfusion. Understanding the mechanisms underlying spontaneous reperfusion is therefore important since this may identify possible novel therapeutic targets to improve outcomes in patients with STEMI. In this review, we discuss some of the possible determinants of spontaneous reperfusion including pro-thrombotic profile, endogenous fibrinolytic status, lipoprotein(a) (Lp[a]), inflammatory markers, and neutrophil extracellular traps (NETs). Effective (rapid) endogenous fibrinolysis, as assessed in whole blood in vitro, using a point-of-care technique assessment of global thrombotic status, has been strongly linked to spontaneous reperfusion. Lp(a), which has a high degree of homology to plasminogen, may impair fibrinolysis through competitive inhibition of tissue plasminogen activator-mediated plasminogen activation as well as tissue plasminogen activator-mediated clot lysis and contribute to pathogenic clot properties by decreasing fibrin clot permeation. NETs appear to negatively modulate clot lysis by increasing thrombin fiber diameter and inhibiting plasmin-driven lysis of plasma clots. There are limited data that oral anticoagulation may modulate endogenous fibrinolysis but antiplatelet agents currently appear to have no impact. Phase III trials involving subcutaneous P2Y12 or glycoprotein IIb/IIIa inhibitors, oral factor XIa inhibitors, interleukin-6 inhibitors, and apolipoprotein(a) antisense oligonucleotides in patients with cardiovascular disease are ongoing. Future studies will be needed to determine the impact of these novel antithrombotic, anti-inflammatory, and lipid-lowering therapies on endogenous fibrinolysis and spontaneous reperfusion.

Tranexamic Acid: An Evergreen Hemostatic Agent

AbstractTranexamic acid (TXA) is an important antifibrinolytic agent, which inhibits plasminogen activation and fibrinolysis. Several controlled randomized trials have investigated the role of TXA in preventing or decreasing blood loss across different surgical interventions or medical conditions characterized by excessive bleeding, consistently documenting its effectiveness and safety. Although the first clinical use of TXA dates back to more than 60 years ago, TXA remains the focus of intense research. This narrative review summarizes the more recent results and indications on the clinical use of TXA.

Effectiveness of Tranexamic Acid in Trauma Patients: A Systematic Review.

Tranexamic acid (TXA), a fibrinolytic agent, effectively inhibits plasminogen activation, thereby reducing fibrinolysis and hemorrhage. This study focused on its application in trauma patients undergoing emergency surgery, a critical area due to trauma's significant role in mortality. Our investigation involved a meticulous screening of randomized controlled trials from databases including Scopus, PubMed, Web of Science, and Cochrane. The findings indicate that TXA intervention is promising in enhancing outcomes for trauma patients.However, the drug's effectiveness may vary based on the specific nature of the medical condition. In summary, robust evidence suggests that TXA can diminish blood loss, lower transfusion rates, reduce complications, and improve hemoglobin and hematocrit levels in surgical patients. Consequently, TXA should be considered a crucial medication, readily available to mitigate morbidity and mortality in surgical settings. Future research should explore factors influencing TXA's effectiveness in traumatic brain injury cases and across a broad spectrum of surgical scenarios in diverse patient populations. This would further guide clinicians in refining and optimizing the use of TXA.

DNA METHYLATION-BASED BIOLOGICAL AGING, PLASMA PROTEINS, AND INCIDENT FRAILTY AND PHYSICAL DISABILITY

Abstract Decline in physical function occurs with advanced age, and biological aging may be a useful marker of decline in physical function, beyond chronological age. This study investigated the associations between DNA methylation-based biological aging (DNAm-based age acceleration (AA)) and plasma proteins and the risk of frailty (based on Fried phenotype and a frailty deficit accumulation index (FI)), and persistent physical disability (defined as loss of ability to perform one or more Katz ADL), among community-dwelling people aged ≥70 years enrolled in the ASPREE study. Five AA indices (Horvath, Hannum, Pheno, Grim, and DunedinPACE) and seven plasma proteins (including plasminogen activation inhibitor-1 (PAI-1), growth differentiation factor-15 (GDF-15), and leptin) were measured in blood from 560 participants (50.7% women). Incident health events were captured over a mean of 5.2 years. Cox proportional-hazard regression adjusted for gender, education, and cell counts. One-standard deviation (SD) increase in AA was associated with an increased risk of frailty (FI) (GrimAA: HR=1.48 (95% CI, 1.19 – 1.84), and DunedinPACE: HR=1.39 (95% CI, 1.11 – 1.73)) and physical disability (GrimAA: HR=1.78 (95% CI, 1.15 – 2.77)). One-SD increase in plasma proteins except for leptin was associated with a higher risk of frailty (both Fried phenotype and FI) (range HR: 1.26 to 2.14). In conclusion, accelerated Grim age and DunedinPACE appear as markers of physical impairments, even in initially healthy individuals. Variations in plasma protein levels might be helpful for the identification of pathophysiological pathways associated with the increased risk of physical impairment in later life.

The Antiobesity Effects and Potential Mechanisms of Theaflavins.

Theaflavins are the characteristic polyphenols in black tea which can be enzymatically synthesized. In this review, the effects and molecular mechanisms of theaflavins on obesity and its comorbidities, including dyslipidemia, insulin resistance, hepatic steatosis, and atherosclerosis, were summarized. Theaflavins ameliorate obesity potentially via reducing food intake, inhibiting pancreatic lipase to reduce lipid absorption, activating the adenosine monophosphate-activated protein kinase (AMPK), and regulating the gut microbiota. As to the comorbidities, theaflavins ameliorate hypercholesterolemia by inhibiting micelle formation to reduce cholesterol absorption. Theaflavins improve insulin sensitivity by increasing the signaling of protein kinase B, eliminating glucose toxicity, and inhibiting inflammation. Theaflavins ameliorate hepatic steatosis via activating AMPK. Theaflavins reduce atherosclerosis by upregulating nuclear factor erythropoietin-2-related factor 2 signaling and inhibiting plasminogen activator inhibitor 1. In randomized controlled trails, black tea extracts containing theaflavins reduced body weight in overweight people and improved glucose tolerance in healthy adults. The amelioration on the hyperlipidemia and the prevention of coronary artery disease by black tea extracts were supported by meta-analysis.

The Effectiveness of Prehospital Administration of Tranexamic Acid in Reducing Mortality in Trauma Patients: An Overview.

Tranexamic acid (TXA) is an antifibrinolytic drug that reduces bleeding by inhibiting plasminogen activation and fibrin clot degradation. Its role in prehospital trauma management remains unclear. This article aims to systematically review the current evidence on the effect of prehospital TXA administration on mortality in adult and pediatric trauma patients. A literature search was conducted of PubMed, Web of Science, Scopus, and Cochrane databases from March 2023 to August 2023 for studies evaluating the impact of prehospital TXA use on trauma mortality. Inclusion criteria were articles published in the English language in the past 20 years focusing on clinical outcomes of prehospital TXA administration. Data on all-cause mortality, thromboembolic events, and time to TXA administration were extracted. In adult trauma, prehospital TXA appears to reduce early all-cause mortality when given within three hours of injury without increasing thromboembolic risks. Some studies found decreased delayed mortality, while others found no difference. In pediatric trauma, preliminary evidence suggests TXA may lower in-hospital mortality in hemodynamically unstable patients, though higher doses may increase seizure risk. Early prehospital administration of TXA within three hours of adult trauma may reduce mortality through improved hemorrhage control. Potential benefits in pediatric trauma warrant further investigation, balancing efficacy against safety risks such as seizures from high doses. Well-designed randomized trials are needed to validate optimal TXA dosing strategies across age groups and injury severity levels.

Synergism of red blood cells and tranexamic acid in the inhibition of fibrinolysis

BackgroundPostpartum hemorrhage (PPH) is the leading cause of maternal death worldwide. The World Maternal Antifibrinolytic trial showed that antifibrinolytic tranexamic acid (TXA) reduces PPH deaths. Maternal anemia increases the risk of PPH. The World Maternal Antifibrinolytic-2 trial is now assessing whether TXA can prevent PPH in women with anemia. Low red blood cell (RBC) counts promote fibrinolysis by altering fibrin structure and plasminogen activation. ObjectivesWe explored interactions between RBCs and TXA in inhibiting fibrinolysis. MethodsWe used global fibrinolytic assays (ball sedimentation and viscoelasticity) to monitor the lysis of fibrin containing plasminogen and tissue-type plasminogen activator. We applied a fluorogenic kinetic assay to measure plasmin generation in fibrin clots and scanning electron microscopy to study fibrin structure. ResultsAccording to parallel-line bioassay analysis of the fibrin lysis-time data, the antifibrinolytic potency of 4-128 μM TXA was increased in the presence of 10% to 40% (v/v) RBCs. Global fibrinolysis assays showed that the joint effect of RBCs and TXA was about 15% larger than the sum of their individual effects in the inhibition of fibrinolysis. In plasminogen activation, TXA added the same increment of inhibition to the effect of RBCs at any cell count in the fibrin clot. Regarding fibrin structure, TXA thickened fibrin fibers, which impaired plasminogen activation, whereas RBCs promoted fine fibers that were more resistant to plasmin. ConclusionsThe antifibrinolytic potency of TXA is enhanced in fibrin formed in the presence of RBCs through inhibition of plasminogen activation and fibrin lysis, which correlates with modifications of fibrin structures.

Hypofibrinolytic phenotype in Tsumura Suzuki Obese Diabetes (TSOD) mice unrelated to hyperglycemia.

Obesity and diabetes mellitus are associated with increased risk of arterial thrombosis and venous thromboembolism. Tsumura Suzuki Obese Diabetes (TSOD) mice are useful models for elucidating the molecular mechanisms of these diseases. We investigated normoglycemic [Ng]-TSOD mice with a metabolic abnormality that was accompanied by a coagulative and fibrinolytic state with a phenotype that distinctly differed from that of standard TSOD mice. As in TSOD mice, plasminogen activation inhibitor-1 (PAI-1) that inhibits fibrinolysis was substantially augmented in Ng-TSOD mice, suggesting that they are hypofibrinolytic. However, blood clotting parameters were within the normal range in Ng-TSOD mice. These findings indicated that Ng-TSOD mice are novel models with a hypofibrinolytic phenotype that is not associated with hyperglycemia.

Prostaglandin E2 attenuates lung fibroblast differentiation via inactivation of yes-associated protein signaling.

Prostaglandin E2 (PGE2 ) has been implicated in counteracting fibroblast differentiation by TGFβ1 during pulmonary fibrosis. However, the precise mechanism is not well understood. We show here that PGE2 via EP2 R and EP4 R inhibits the expression of mechanosensory molecules Lysyl Oxidase Like 2 (LOXL2), myocardin-related transcription factor A (MRTF-A), ECM proteins, plasminogen activation inhibitor 1 (PAI-1), fibronectin (FN), α-smooth muscle actin (α-SMA), and redox sensor (nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4)) required for TGFβ1-mediated fibroblast differentiation. We further demonstrate that PGE2 inhibits fibrotic signaling via Yes-associated protein (YAP) but does so independently from its actions on SMAD phosphorylation and conserved cylindromatosis (CYLD; deubiquitinase) expression. Mechanistically, PGE2 phosphorylates/inactivates YAP downstream of EP2 R/Gαs and restrains its translocation to the nucleus, thus inhibiting its interaction with TEA domain family members (TEADs) and transcription of fibrotic genes. Importantly, pharmacological or siRNA-mediated inhibition of YAP significantly downregulates TGFβ1-mediated fibrotic gene expression and myofibroblast formation. Notably, YAP expression is upregulated in the lungs of D. farinae-treated wild type (WT) mice relative to saline-treated WT mice. Our results unravel a unique role for PGE2 -YAP interactions in fibroblast differentiation, and that PGE2 /YAP inhibition can be used as a novel therapeutic target in the treatment of pathological conditions associated with myofibroblasts like asthma.

Genetic Predisposition to Adverse Neurodevelopmental Outcome of Extremely Low Birth Weight Infants.

This study aimed to evaluate whether there are genetic variants associated with adverse neurodevelopmental outcomes in extremely low birth weight (ELBW) infants. We conducted a candidate gene association study in two well-defined cohorts of ELBW infants (<1,000 g). One cohort was for discovery and the other for replication. The discovery case-control analysis utilized anonymized DNA samples and evaluated 1,614 single-nucleotide polymorphisms (SNPs) in 145 genes concentrated in inflammation, angiogenesis, brain development, and oxidation pathways. Cases were children who died by age one or who were diagnosed with cerebral palsy (CP) or neurodevelopmental delay (Bayley II mental developmental index [MDI] or psychomotor developmental index [PDI] < 70) by 18 to 22 months. Controls were survivors with normal neurodevelopment. We assessed significant epidemiological variables and SNPs associated with the combined outcome of CP or death, CP, mental delay (MDI < 70) and motor delay (PDI < 70). Multivariable analyses adjusted for gestational age at birth, small for gestational age, sex, antenatal corticosteroids, multiple gestation, racial admixture, and multiple comparisons. SNPs associated with adverse neurodevelopmental outcomes with p < 0.01 were selected for validation in the replication cohort. Successful replication was defined as p < 0.05 in the replication cohort. Of 1,013 infants analyzed (452 cases, 561 controls) in the discovery cohort, 917 were successfully genotyped for >90% of SNPs and passed quality metrics. After adjusting for covariates, 26 SNPs with p < 0.01 for one or more outcomes were selected for replication cohort validation, which included 362 infants (170 cases and 192 controls). A variant in SERPINE1, which encodes plasminogen activator inhibitor (PAI1), was associated with the combined outcome of CP or death in the discovery analysis (p = 4.1 × 10-4) and was significantly associated with CP or death in the replication cohort (adjusted odd ratio: 0.4; 95% confidence interval: 0.2-1.0; p = 0.039). A genetic variant in SERPINE1, involved in inflammation and coagulation, is associated with CP or death among ELBW infants. · Early preterm and ELBW infants have dramatically increased risks of CP and developmental delay.. · A genetic variant in SERPINE1 is associated with CP or death among ELBW infants.. · The SERPINE1 gene encodes the serine protease inhibitor plasminogen activator inhibitor..

Accelerated epigenetic clock aging in maternal peripheral blood and preterm birth

Epigenetic clocks use CpG DNA methylation to estimate biological age. Acceleration is associated with cancer, heart disease, and shorter life span. Few studies evaluate DNA methylation age and pregnancy outcomes. AgeAccelGrim is a novel epigenetic clock that combines 7 DNA methylation components. This study aimed to determine whether maternal biological aging (via AgeAccelGrim) is associated with early preterm birth. A prospective cohort of patients with singleton pregnancies and at high risk of spontaneous preterm birth delivering at a tertiary university hospital were included in this study. Genome-wide CpG methylation was measured using the Illumina EPIC BeadChip (Illumina, Inc, San Diego, CA) from maternal blood samples obtained at <28 weeks of gestation. AgeAccelGrim and its 7 DNA methylation components were estimated by the Horvath DNA methylation age online tool. Positive values are associated with accelerated biological aging, whereas negative values are associated with slower biological aging relative to each subject's age. The primary outcome was preterm birth at <34 weeks of gestation (any indication). The secondary outcomes were preterm birth at <37 and <28 weeks of gestation. AgeAccelGrim was analyzed as a continuous variable and in quartiles. Exploratory analyses evaluated each of the 7 DNA methylation components included in the composite AgeAccelGrim. Data were analyzed by chi-square test, t test, rank-sum test, logistic regression (controlling a priori for maternal age, cell counts, low socioeconomic status, and gestational age at the time of sample collection), and Kaplan-Meier survival analyses. The log-rank test was used to test the equality of the survival functions. Overall, 163 patients met the inclusion criteria. Of the patients, 48%, 39%, and 21% delivered at <37, <34, and <28 weeks of gestation, respectively. The median AgeAccelGrim was-0.35 years (interquartile range,-2.24 to 1.31) for those delivering at term. Those delivering preterm had higher AgeAccelGrim values that were inversely proportional to delivery gestational age (preterm birth at <37 weeks of gestation:+0.40 years [interquartile range:-1.21 to+2.28]; preterm birth at <34 weeks of gestation:+0.51 years [interquartile range:-1.05 to+2.67]; preterm birth at <28 weeks of gestation:+1.05 years [interquartile range:-0.72 to+2.72]). Estimated DNA methylation of the 7 epigenetic clock component values was increased among those with preterm birth at <34 weeks of gestation, although the differences were only significant for DNA methylation of plasminogen activation inhibitor 1. In regression models, AgeAcccelGrim was associated with an elevated risk of preterm birth with increasing magnitude for increasing severity of preterm birth. For each 1-year increase in the AgeAccelGrim value (ie, each 1-year increase in biological age compared with chronologic age), the adjusted odds of preterm birth were 11% (adjusted odds ratio, 1.11; 95% confidence interval, 1.00-1.24), 13% (adjusted odds ratio, 1.13; 95% confidence interval, 1.01-1.26), and 18% (adjusted odds ratio, 1.18; 95% confidence interval, 1.04-1.35) higher for preterm birth at <37, <34, and <28 weeks of gestation, respectively. Similarly, individuals with accelerated biological aging (≥75th percentile AgeAccelGrim) had more than double the odds of preterm birth at <34 weeks of gestation (adjusted odds ratio, 2.36; 95% confidence interval, 1.10-5.08) and more than triple the odds of preterm birth at <28 weeks of gestation (adjusted odds ratio, 3.89; 95% confidence interval, 1.61-9.38). The adjusted odds ratio for preterm birth at <37 weeks of gestation was 1.73 but spanned the null (adjusted odds ratio, 1.73; 95% confidence interval, 0.81-3.69). In Kaplan-Meier survival analyses, those in the highest AgeAccelGrim quartile delivered the earliest (log-rank Pvalue of <.001). Accelerated biological aging was associated with preterm birth among high-risk patients. Future research confirming these findings and elucidating factors that slow biological aging may improve birth outcomes.

Plasma interleukin-6 (IL-6), angiopoietin-2, and C-reactive protein levels predict subsequent type 1 myocardial infarction in persons with treated HIV infection.

HIV infection leads to endothelial activation, promoting platelet adhesion and accelerating atherosclerosis. Our goal was to determine whether biomarkers of endothelial activation and hemostasis/thrombosis were elevated in people with treated HIV (PWH) before myocardial infarction (MI). In a case-control study nested within the CFAR Network of Integrated Clinical Systems (CNICS) cohort, we compared 69 adjudicated cases with type 1 MI to 138 controls matched for ART regimen. We measured angiopoietin-1, angiopoietin-2 (ANG-2), ICAM-1, VCAM-1, ADAMTS13, von Willebrand factor, C-reactive protein (CRP), interleukin-6 (IL-6), plasminogen activation inhibitor-1, P-selectin, serum amyloid-A, soluble CD14, and apolipoprotein A1 in stored plasma. Conditional logistic regression identified associations with subsequent MI, with and without adjustment for Atherosclerotic Cardiovascular Disease (ASCVD) and Veterans Aging Cohort Study (VACS) scores. Higher IL-6 was associated with MI after adjustment for ASCVD score (adjusted odds ratio [AOR] 1.51, 95% CI, 1.05-2.17 per standard-deviation-scaled log2 increment). In a separate model adjusting for VACS score, higher ANG-2 (AOR 1.49, 95% CI 1.04-2.14), higher CRP (AOR 1.45, 95% CI 1.06-2.00), and higher IL-6 (AOR 1.68, 95% CI 1.17-2.41) were associated with MI. In a sensitivity analysis excluding PWH with viral load ≥400 copies/mL, higher IL-6 remained associated with MI after adjustment for ASCVD score and after adjustment for VACS score. Among PWH, higher levels of plasma IL-6, CRP, and ANG-2 predict subsequent type 1 MI, independent of conventional risk scores. IL-6 had the most consistent associations with type 1 MI, regardless of viral load suppression.

EFFECTS OF TRANEXAMIC ACID ON NEUROPATHOLOGY, ELECTROENCEPHALOGRAPHY, AND CEREBRAL FIBRIN DEPOSITION IN A RAT MODEL OF POLYTRAUMA WITH CONCOMITANT PENETRATING TRAUMATIC BRAIN INJURY.

Several studies have demonstrated the clinical utility of tranexamic acid (TXA) for use in trauma patients presenting with significant hemorrhage. Tranexamic acid is an antifibrinolytic that inhibits plasminogen activation, and plasmin activity has been shown to mitigate blood loss and reduce all-cause mortality in the absence of adverse vascular occlusive events. Recent clinical developments indicate TXA is safe to use in patients with concomitant traumatic brain injury (TBI); however, the prehospital effects are not well understood. Importantly, TXA has been associated with seizure activity. Therefore, this study sought to evaluate the effects of early administration of TXA on neurological recovery and electroencephalogram (EEG) abnormalities following penetrating TBI with concomitant hypoxemia and hemorrhagic shock. We hypothesized that early administration of TXA will provide hemodynamic stabilization and reduce intracerebral hemorrhage, which will result in improved neurological function. To test this hypothesis, Sprague-Dawley rats received a unilateral, frontal penetrating ballistic-like brain injury by inserting a probe into the frontal cortex of the anesthetized rat. Five minutes following brain injury, animals underwent 30 min of respiratory distress and 30 min of hemorrhage. Upon completion of the hemorrhage phase, animals received the initial dose of drug intravenously over 10 min after which the prehospital phase was initiated. During the prehospital phase, animals received autologous shed whole blood as needed to maintain a MAP of 65 mm Hg. After 90 min, "in-hospital" resuscitation was performed by administering the remaining shed whole blood providing 100% oxygen for 15 min. Upon recovery from surgery, animals were administered their second dose of vehicle or TXA intravenously over 8 h. Tranexamic acid induced an early improvement in neurologic deficit, which was statistically significant compared with vehicle at 24, 48, and 72 h at three doses tested. Analysis of cerebral hemoglobin content and intracerebral lesion progression revealed 100 mg/kg provided the optimal effects for improvement of neuropathology and was continued for determination of adverse treatment effects. We observed no exacerbation of cerebral thrombosis, but TXA treatment caused an increased risk of EEG abnormalities. These results suggest that TXA following polytrauma with concomitant brain injury may provide mild neuroprotective effects by preventing lesion progression, but this may be associated with an increased risk of abnormal EEG patterns. This risk may be associated with TXA inhibition of glycine receptors and may warrant additional considerations during the use of TXA in patients with severe TBI.

CTSS Modulates Stress-Related Carotid Artery Thrombosis in a Mouse FeCl3 Model.

Exposure to chronic psychological stress is a risk factor for metabolic cardiovascular disease. Given the important role of lysosomal CTSS (cathepsin S) in human pathobiology, we examined the role of CTSS in stress-related thrombosis, focusing on inflammation, oxidative stress, and apoptosis. Six-week-old wild-type mice (CTSS+/+) and CTSS-deficient mice (CTSS-/-) randomly assigned to nonstress and 2-week immobilization stress groups underwent iron chloride3 (FeCl3)-induced carotid thrombosis surgery for morphological and biochemical studies. On day 14 poststress/surgery, stress had increased the lengths and weights of thrombi in the CTSS+/+ mice, plus harmful changes in the levels of PAI-1 (plasminogen activation inhibitor-1), ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 13 motifs), and vWF (von Willebrand factor) and arterial tissue CTSS expression. Compared to the nonstressed CTSS+/+ mice, the stressed CTSS-/- mice had decreased levels of PAI-1, vWF, TNF (tumor necrosis factor)-α, interleukin-1β, toll-like receptor-4, cleaved-caspase 3, cytochrome c, p16INK4A, gp91phox, p22phox, ICAM-1 (intercellular adhesion molecule-1), MCP-1 (monocyte chemoattractant protein-1), MyD88 (myeloid differentiation primary response 88), and MMP (matrix metalloproteinase)-2/-9 and increased levels of ADAMTS13, SOD (superoxide dismutase)-1/-2, eNOS (endothelial NO synthase), p-Akt (phospho-protein kinase B), Bcl-2 (B-cell lymphoma-2), p-GSK3α/β (phospho-glycogen synthase kinases alpha and beta), and p-Erk1/2 (phospho-extracellular signal-regulated kinase 1 and 2) mRNAs and/or proteins. CTSS deletion also reduced the arterial thrombus area and endothelial loss. A pharmacological inhibition of CTSS exerted a vasculoprotective action. In vitro, CTSS silencing and overexpression, respectively, reduced and increased the stressed serum and oxidative stress-induced apoptosis of human umbilical vein endothelial cells, and they altered apoptosis-related proteins. CTSS inhibition appeared to improve the stress-related thrombosis in mice that underwent FeCl3-induction surgery, possibly by reducing vascular inflammation, oxidative stress, and apoptosis. CTSS could thus become a candidate therapeutic target for chronic psychological stress-related thrombotic events in metabolic cardiovascular disease.

Abstract 4879: Inhibition of amino acid transporters as a novel mechanism of action of the repurposed anti-cancer agent tranexamic acid

Abstract Tranexamic Acid (TA) is an anti-fibrinolytic agent that inhibits Plasminogen activation and is used to control bleeding. Past studies have suggested that the ability of TA to block Plasminogen activation may be useful for ablating the growth or invasion of cancer. Based on the similarity of TA to the amino acid Lysine we hypothesize that TA might exhibit novel mechanisms of action independent of blocking Plasminogen activation. Analysis of a series of signaling pathways indicated that TA inhibits phosphorylation of S6K1 and STAT3 on sites required for their activation and reduces expression of the MYC oncogene in a concentration-dependent manner. Interestingly, MYC transformed MCF10A human mammary epithelial cells exhibited enhanced sensitivity to TA-mediated reduction of cell viability, suggesting that TA may exhibit selectivity for MYC overexpressing breast cancers. Treatment of breast tumor bearing mice with TA strongly blocked tumor growth and was associated with extensive cancer cell death compared with control tumors. Analysis of extracts from TA or vehicle treated tumors showed that TA blocked S6K1 phosphorylation in vivo in a statistically significant manner. Since S6K1 phosphorylation is regulated by amino acid levels, we hypothesized that due to the structural similarity between TA and Lysine and Arginine, TA may block Lysine or Arginine uptake by blocking cationic amino acid transporters (CATs). Molecular docking simulations utilizing the structure of the bacterial CAT predicted that TA binds to CAT with affinity similar to that of Lysine. Amino acid uptake experiments performed with radiolabeled Arginine and Lysine showed that TA blocked both Arginine and Lysine absorption by cancer cells in a concentration-dependent manner. Together, these results indicate a novel mechanism by which TA inhibits uptake of Arginine and Lysine, triggering loss of S6K1 activity in parallel with tumor growth inhibition. Initial studies suggest the feasibility of designing TA analogs with significantly improved potency for amino acid transporters, and with corresponding increases in selective toxicity to breast cancer cells. Based on these novel mechanisms of TA action, we expect TA to exhibit anti-cancer activity against a broad range of human malignancies. Citation Format: Brian K. Law, Mary E. Law, Amanda F. Ghilardi, Elham Yaaghubi, Brad J. Davis, Zaafir M. Dulloo, Mengxiong Wang, Olga A. Guryanova, Coy D. Heldermon, Stephan C. Jahn, Ronald K. Castellano. Inhibition of amino acid transporters as a novel mechanism of action of the repurposed anti-cancer agent tranexamic acid. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4879.

Glucocorticoid-Responsive Tissue Plasminogen Activator (tPA) and Its Inhibitor Plasminogen Activator Inhibitor-1 (PAI-1): Relevance in Stress-Related Psychiatric Disorders.

Stressful events trigger a set of complex biological responses which follow a bell-shaped pattern. Low-stress conditions have been shown to elicit beneficial effects, notably on synaptic plasticity together with an increase in cognitive processes. In contrast, overly intense stress can have deleterious behavioral effects leading to several stress-related pathologies such as anxiety, depression, substance use, obsessive-compulsive and stressor- and trauma-related disorders (e.g., post-traumatic stress disorder or PTSD in the case of traumatic events). Over a number of years, we have demonstrated that in response to stress, glucocorticoid hormones (GCs) in the hippocampus mediate a molecular shift in the balance between the expression of the tissue plasminogen activator (tPA) and its own inhibitor plasminogen activator inhibitor-1 (PAI-1) proteins. Interestingly, a shift in favor of PAI-1 was responsible for PTSD-like memory induction. In this review, after describing the biological system involving GCs, we highlight the key role of tPA/PAI-1 imbalance observed in preclinical and clinical studies associated with the emergence of stress-related pathological conditions. Thus, tPA/PAI-1 protein levels could be predictive biomarkers of the subsequent onset of stress-related disorders, and pharmacological modulation of their activity could be a potential new therapeutic approach for these debilitating conditions.

Effectiveness of prophylactic tranexamic acid versus placebo or no intervention for reducing blood loss in healthy patients undergoing orthognathic surgery: a systematic review protocol.

The objective of this review is to evaluate the effectiveness of perioperative prophylactic tranexamic acid for reducing blood loss in orthognathic surgery in healthy patients. Orthognathic surgery can cause significant hemorrhage, which requires postoperative blood transfusions. The most widely studied pharmaceutical adjunct for reducing blood loss is tranexamic acid, a synthetic amino acid that reversibly inhibits plasminogen activation. It is widely used and validated in other surgical procedures to limit blood loss; however, it is not a gold standard in orthognathic surgery. We will include clinical trials comparing tranexamic acid to appropriate controls. The primary outcomes are intraoperative blood loss, change in hematocrit/hemoglobin level, and need for blood transfusion. Secondary outcomes include operating time, length of hospital stay, and adverse reactions. Studies of patients with pre-existing coagulopathies and those undergoing only minor orthognathic surgery (eg, genioplasty) will be excluded. We will search 3 electronic databases (PubMed, Embase, and Cochrane Library) from database inception. Titles, abstracts, and full-text papers will be assessed against the inclusion criteria by 2 independent reviewers. Risk of bias will be assessed using the Cochrane Risk of Bias 2.0 tool. Data will be extracted by 2 independent reviewers. Meta-analysis will be conducted for all outcomes where appropriate, with weighted mean differences used for intraoperative blood loss, changes in hematocrit/hemoglobin levels, operation time, and length of stay; and risk ratio for transfusion rates and adverse outcomes. Certainty of the evidence will be presented using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. PROSPERO CRD42022314403.

First Massive Transfusion Protocol (MTP) Implementation Proposal in Egypt

Abstract Introduction/Objective Massive transfusion is often defined as transfusion of adults with 10 or more of packed red blood cells units in 24 hours period or transfusion of 4 or more units of packed red blood cells (PRBCs) in one hour when on-going need for more transfusion is foreseeable. Massive transfusion protocol in children is defined as transfusion of &amp;gt;40 mL/kg. Massive transfusion protocol (MTP) is a vital element of damage control resuscitation and provides a coordinated clinical response to hemorrhage in patients requiring massive blood transfusions after hospital admission. Hemorrhage is the most common cause of death within the first hour of arrival to the trauma center. Methods/Case Report This study aims to develop and establish the first massive protocol in Egypt to provide a consistent treatment for blood transfusion for trauma patients that will Reduce delay in ordering and administering blood products and Deliver a reasonable ratio of plasma to red blood cells. The protocol will be first implemented in a military hospital in Egypt. Developing the massive transfusion protocol will allow the practitioners to follow algorithm for rapid replacement of blood products using uncrossmatched packed red blood cells, Plasma, platelets and cryoprecipitate if necessary. Adopting the American Association of Blood Banks (AABB) and the American College of Surgeons (ACS) guidelines are the best practice around the world. The Protocol will be developed by multidisciplinary committee engagement, Blood bank, Diagnostic laboratory and Clinical care areas (OR, ER, ICU, OBS). Results (if a Case Study enter NA) The massive transfusion protocol ratio will be 3:2 (RBC: FFP) and one units of platelets for every 6 units of RBC. according to American College of Surgeons (ACS) guidelines the ratio should be 1:1 to 1:2 (RBC: FFP). The committee established defined criteria for MTP activation and termination. The delivery time of the blood products should be between 5-10 minutes. Administration of tranexamic acid to inhibit plasminogen activation and stabilize the clot. Conclusion The Developing and Implementing MTP in Egypt will provide reduction in mortality for trauma and uncontrolled hemorrhage patients. Once implemented, we will regularly evaluate the use and efficacy of the MTP to ensure positive patient outcomes., the MTP will be evaluated to ensure best practice.