Sex dimorphisms in coagulation: Implications in trauma-induced coagulopathy and trauma resuscitation.

Trauma-induced coagulopathy (TIC) is one of the leading causes of preventable death in injured patients. Consequently, it is imperative to understand the mechanisms underlying TIC and how to mitigate this mortality. An opportunity for advancement stems from the awareness that coagulation demonstrates a strong sex-dependent effect. Females exhibit a relative hypercoagulability compared to males, which persists after injury and confers improved outcomes. The mechanisms underlying sex dimorphisms in coagulation and its protective effect after injury have yet to be elucidated. This review explores sex dimorphisms in enzymatic hemostasis, fibrinogen, platelets, and fibrinolysis, with implications for resuscitation of patients with TIC.

Prothrombin Knockdown Protects Podocytes and Reduces Proteinuria in Glomerular Disease.

Chronic kidney disease (CKD) is a leading cause of death, and its progression is driven by glomerular podocyte injury and loss, manifesting as proteinuria. Proteinuria includes urinary loss of coagulation zymogens, cofactors, and inhibitors. Importantly, both CKD and proteinuria significantly increase the risk of thromboembolic disease. Prior studies demonstrated that anticoagulants reduced proteinuria in rats and that thrombin injured cultured podocytes. Herein we aimed to directly determine the influence of circulating prothrombin on glomerular pathobiology. We hypothesized that (pro)thrombin drives podocytopathy, podocytopenia, and proteinuria. Glomerular proteinuria was induced with puromycin aminonucleoside (PAN) in Wistar rats. Circulating prothrombin was either knocked down using a rat-specific antisense oligonucleotide or elevated by serial intravenous infusions of prothrombin protein, which are previously established methods to model hypo- (LoPT) and hyper-prothrombinemia (HiPT), respectively. After 10 days (peak proteinuria in this model) plasma prothrombin levels were determined, kidneys were examined for (pro)thrombin co-localization to podocytes, histology, and electron microscopy. Podocytopathy and podocytopenia were determined and proteinuria, and plasma albumin were measured. LoPT significantly reduced prothrombin colocalization to podocytes, podocytopathy, and proteinuria with improved plasma albumin. In contrast, HiPT significantly increased podocytopathy and proteinuria. Podocytopenia was significantly reduced in LoPT vs. HiPT rats. In summary, prothrombin knockdown ameliorated PAN-induced glomerular disease whereas hyper-prothrombinemia exacerbated disease. Thus, (pro)thrombin antagonism may be a viable strategy to simultaneously provide thromboprophylaxis and prevent podocytopathy-mediated CKD progression.

Glucocorticoid- and pioglitazone-induced proteinuria reduction in experimental NS both correlate with glomerular ECM modulation.

Idiopathic nephrotic syndrome (NS) is a common glomerular disease. Although glucocorticoids (GC) are the primary treatment, the PPARγ agonist pioglitazone (Pio) also reduces proteinuria in patients with NS and directly protects podocytes from injury. Because both drugs reduce proteinuria, we hypothesized these effects result from overlapping transcriptional patterns. Systems biology approaches compared glomerular transcriptomes from rats with PAN-induced NS treated with GC vs. Pio and identified 29 commonly regulated genes-of-interest, primarily involved in extracellular matrix (ECM) remodeling. Correlation with clinical idiopathic NS patient datasets confirmed glomerular ECM dysregulation as a potential mechanism of injury. Cellular deconvolution in silico revealed GC- and Pio-induced amelioration of altered genes primarily within podocytes and mesangial cells. While validation studies are indicated, these analyses identified molecular pathways involved in the early stages of NS (prior to scarring), suggesting that targeting glomerular ECM dysregulation may enable a future non-immunosuppressive approach for proteinuria reduction in idiopathic NS.

Reciprocal stabilization of coagulation factor XIII-A and -B subunits is a determinant of plasma FXIII concentration.

ABSTRACT: Transglutaminase factor XIII (FXIII) is essential for hemostasis, wound healing, and pregnancy maintenance. Plasma FXIII is composed of A and B subunit dimers synthesized in cells of hematopoietic origin and hepatocytes, respectively. The subunits associate tightly in circulation as FXIII-A2B2. FXIII-B2 stabilizes the (pro)active site-containing FXIII-A subunits. Interestingly, people with genetic FXIII-A deficiency have decreased FXIII-B2, and therapeutic infusion of recombinant FXIII-A2 (rFXIII-A2) increases FXIII-B2, suggesting FXIII-A regulates FXIII-B secretion, production, and/or clearance. We analyzed humans and mice with genetic FXIII-A deficiency and developed a mouse model of rFXIII-A2 infusion to define mechanisms mediating plasma FXIII-B levels. Like humans with FXIII-A deficiency, mice with genetic FXIII-A deficiency had reduced circulating FXIII-B2, and infusion of FXIII-A2 increased FXIII-B2. FXIII-A-deficient mice had normal hepatic function and did not store FXIII-B in liver, indicating FXIII-A does not mediate FXIII-B secretion. Transcriptional analysis and polysome profiling indicated similar F13b levels and ribosome occupancy in FXIII-A-sufficient and -deficient mice and in FXIII-A-deficient mice infused with rFXIII-A2, indicating FXIII-A does not induce de novo FXIII-B synthesis. Unexpectedly, pharmacokinetic/pharmacodynamic modeling of FXIII-B antigen after rFXIII-A2 infusion in humans and mice suggested FXIII-A2 slows FXIII-B2 loss from plasma. Accordingly, comparison of free FXIII-B2 vs FXIII-A2-complexed FXIII-B2 (FXIII-A2B2) infused into mice revealed faster clearance of free FXIII-B2. These data show FXIII-A2 prevents FXIII-B2 loss from circulation and establish the mechanism underlying FXIII-B2 behavior in FXIII-A deficiency and during rFXIII-A2 therapy. Our findings reveal a unique, reciprocal relationship between independently synthesized subunits that mediate an essential hemostatic protein in circulation. This trial was registered at www.ClinicalTrials.com as #NCT00978380.

Prognostic Value of Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Imaging for Predicting Venous Thromboembolism in Children With Lymphoma.

BACKGROUND: Positron emission tomography (PET)/computed tomography (CT) imaging can detect changes in arterial inflammation, but has not been used to evaluate chemotherapy-induced venous inflammation or assess risk for venous thromboembolism (VTE) in pediatric oncology. Therefore, the purpose of this study was to evaluate the prognostic value of fluorine-18-fluorodeoxyglucose PET/CT imaging of venous inflammation for predicting VTE occurrence in the 12 months after lymphoma diagnosis in pediatric, adolescent, and young adult patients. METHODS: Pediatric, adolescent, and young adult patients with lymphoma diagnoses (n=71) who underwent whole-body PET/CT imaging at initial staging of disease and first therapeutic follow-up were retrospectively evaluated for serial changes in lower extremity venous uptake of fluorine-18-fluorodeoxyglucose. PET/CT images were used to segment and quantify serial changes in fluorine-18-fluorodeoxyglucose uptake for veins of interest (ie, popliteal and femoral). Incidence of VTE was assessed for 12 months after lymphoma diagnosis. RESULTS: PET/CT detected a significantly higher inflammatory response in the femoral (P=0.012) and popliteal (P=0.013) veins of patients who experienced a VTE event compared with those who remained VTE free in the 12 months after diagnosis. The area under the curve values for receiver operator characteristics analyses were 0.76 (femoral vein) and 0.77 (popliteal vein) based on incidence of VTE occurrence. Univariate analyses demonstrated that PET/CT-derived changes in femoral (P=0.008) and popliteal (P=0.002) vein inflammation were significantly associated with VTE-free survival at 12 months after diagnosis. CONCLUSIONS: Fluorine-18-fluorodeoxyglucose PET/CT imaging detects treatment-induced venous toxicity that may provide insight into risk of VTE events in pediatric and adolescent and young adult patients with lymphoma.

A regional anticoagulation program improves safety and outcomes for both children and adults.

BACKGROUND: Evidence-based anticoagulation programs usually serve a local, adult patient population. Here we report outcomes for a regional combined pediatric-adult program. AIMS: The aims of this study were: (1) Compare the pre- vs. post-implementation quality of therapy (% time in therapeutic range (%TTR) and compliance). (2) Assess anticoagulant-relevant outcomes (bleeding and thrombotic complications). METHODS: Data were collected for the years 2014-2019. Rosendaal linear interpolation was used to calculate %TTR. Bleeding complications were categorized using ISTH-SSC standard nomenclature and new thrombotic events were reviewed. RESULTS: The patients were divided into a long-term warfarin group (N = 308), 80.2% of whom had cardiac-related therapeutic indications (median age 24y), and a second group (N = 114) comprised of short-term and non-warfarin long-term anticoagulation (median age 16y). Median %TTR for those on long-term warfarin was 78.9%. The incidence of major and clinically relevant non-major bleeding events was 1.65 and 2.43 /100 person-years of warfarin use, respectively. Thromboembolism (TE) incidence was 0.78/100 patient-years of warfarin use. Neither bleeding nor thrombosis was associated with %TTR (p = 0.48). Anticoagulant indication was the only variable associated with bleeding risk (p = 0.005). The second group had no on-therapy TE events but 7.9% experienced bleeding. Complete data were available for a randomly sampled pre-program warfarin group (N = 26). Median %TTR improved from 17.5 to 87% pre- vs. post-implementation. Similarly, compliance (defined as ≥ 1 INR/month) improved by 34.3%. CONCLUSIONS: In conclusion, this program significantly improved and sustained %TTR and compliance. The lack of association between bleeding and thrombosis events and %TTR may be related to the high median %TTR (> 70%) achieved by this approach.

Exploring the Role of Antithrombin in Nephrotic Syndrome-Associated Hypercoagulopathy: A Multi-Cohort Study and Meta-Analysis.

BACKGROUND: Nephrotic syndrome is associated with an acquired hypercoagulopathy that is thought to drive its predisposition for venous thromboembolism. Previous studies have suggested that urinary antithrombin (AT) loss leading to acquired AT deficiency is the primary mechanism underlying this hypercoagulopathy, but this hypothesis has not been directly tested. The objectives of this study were to test the influence of AT levels on hypercoagulopathy in nephrotic syndrome patient samples and perform meta-analyses to evaluate the likelihood of AT deficiency in patients with nephrotic syndrome. METHODS: Samples from three independent nephrotic syndrome cohorts were analyzed. AT antigen and activity assays were performed using ELISA and amidolytic assays, respectively. Plasma thrombin generation, albumin, and urine protein-to-creatinine ratios were determined using established methods. Meta-analyses were performed by combining these new data with previously published data. RESULTS: AT levels were not consistently related to either plasma albumin or proteinuria. AT was quantitatively related to hypercoagulopathy in adult nephrotic syndrome, whereas AT activity was inconsistently associated with hypercoagulopathy in childhood nephrotic syndrome. Notably, hypercoagulopathy did not differ between patients with normal AT levels and those with levels below the threshold used to define clinical AT deficiency (<70%). Moreover, ex vivo AT supplementation did not significantly alter hypercoagulopathy in AT-deficient plasma samples. The meta-analyses demonstrated that AT deficiency was not a uniform feature of nephrotic syndrome and was more common in children than adults. CONCLUSIONS: These data suggest that AT deficiency plays only a limited role in the mechanisms underlying the acquired hypercoagulopathy of nephrotic syndrome. Moreover, AT deficiency was not present in all patients with nephrotic syndrome and was more likely in children than adults despite the higher risk for venous thromboembolism in adults than children.

Intracardiac thrombi in pediatrics: anticoagulation approach and treatment outcomes.

Background: Intracardiac thrombi (ICT) are associated with significant morbidity and mortality. Anticoagulation is the first line of treatment and may be complemented by thrombectomy or thrombolysis. However, optimal anticoagulant duration remains ill-defined. High-risk features of ICT that may warrant long-term anticoagulation therapy have not been established. Objectives: To describe anticoagulation duration and patterns of ICT resolution. To identify potential risk factors for persistent ICT despite anticoagulation. Methods: A single-institution retrospective chart review identified patients diagnosed with ICT by echocardiogram between January 2014 and March 2022. Descriptive statistics and logistic regression were used. Results: Fifty-one patients with ICT were identified. Median age at diagnosis was 9.2 years (IQR, 0.4-15.2). The most common underlying diagnoses were congenital heart disease (41%), infection (25%), and malignancy (24%). The majority of ICT were in the right atrium (n = 30). The median longest ICT dimension was 1.5 cm (range, 0.4-4.0). The median duration of anticoagulation was 4.3 months (IQR, 2.2-9.1). Among 48 patients who received anticoagulation as first-line treatment, 32 had partial or complete response with 3 to 6 months of anticoagulation, while remaining 16 patients had no response to anticoagulation. Patients with a central venous line had a delayed resolution of ICT [hazards ratio = 0.45 (95% CI, 0.22-0.93)]. Conclusion: Our study demonstrates the wide variability in duration of anticoagulation for children with ICT. Majority of the individuals benefit from 3-to-6 month treatment; however, individuals with a central venous line may benefit from a longer course of anticoagulation. Further large-scale studies are recommended to validate our findings.

Role of protease-activated receptor-1 (PAR-1) in the glomerular filtration barrier integrity.

Protease-activated receptors (PAR) play an important role in the regulation of cellular function by the coagulation system, and they are activated by thrombin. PAR-1 is expressed in both endothelial cells and podocytes in the kidney. The role of PAR1 in the maintenance of the glomerular filtration barrier is not clear. Anticoagulant-related nephropathy (ARN) is a kidney disease with glomerular hematuria and red blood cell tubular casts. We validated 5/6 nephrectomy (5/6NE) in rats as a model of ARN and had demonstrated that direct thrombin inhibitor (dabigatran) induces ARN. The aim of this study was to investigate the role of PAR-1 in the ARN pathogenesis. 5/6NE rats were treated with dabigatran (150 mg/kg/day), PAR-1 inhibitor SCH79797 (1 and 3 mg/kg/day) and PAR-1 agonist TFLLR-NH2 (0.25 and 0.50 µmol/kg/day) for 7 days. Serum creatinine and hematuria were assessed daily. Kidney morphology was evaluated at the end of the study. In 5/6NE rats treated with either dabigatran or combination with a PAR-1 modulator, there was an elevation in serum creatinine, glomerular hematuria, red blood casts in the tubules, and acute tubular epithelial cell injury. Interestingly, both PAR-1 modulators in a dose-depended manner had similar effects on the serum creatinine levels and hematuria as those of dabigatran. Dabigatran-induced increase in the systolic blood pressure was not affected by PAR-1 modulators. In conclusion, the normal function of PAR-1 is crucial to maintain the glomerular filtration barrier integrity. Either activation or blockage of PAR-1 leads to glomerular hematuria and subsequent acute tubular epithelial cell injury.

Moderate-intensity aerobic exercise vs desmopressin in adolescent males with mild hemophilia A: a randomized trial.

Persons with mild hemophilia A (HA) may use intranasal desmopressin prior to sports participation. Desmopressin is expensive and can cause vomiting, headache, palpitation, and occasionally seizures. Our group has previously documented a 2.3-fold increase in factor VIII activity (FVIII:C) in adolescents with mild HA after moderate-intensity aerobic exercise. Herein, we report principal findings of a randomized trial of intranasal desmopressin vs a standardized, moderate-intensity aerobic exercise regimen in adolescents with mild HA. Our primary objective was to compare the change in FVIII:C associated with these 2 interventions. We also examined changes in hemostatic parameters arising from their sequential administration. The study was conducted simultaneously at the Hospital for Sick Children, Canada, and Nationwide Children's Hospital, USA. Thirty-two eligible male adolescents (mean age ± standard deviation: 16.1 ± 2.6 years) with mild HA (mean baseline FVIII:C: 27.9% ± 18.4%) were randomized to 1 of 4 study arms (desmopressin followed by exercise, desmopressin alone, exercise followed by desmopressin, and exercise alone). Blood work was obtained at baseline and at 3 subsequent time-points. Participants randomized to exercise cycled on an ergometer for approximately 12 minutes, with the final 3 minutes at 85% of their predicted maximum heart rate. Standard weight-based dosing of desmopressin was used. Mean immediate increase in FVIII:C was 1.7-fold with exercise compared with 1.9-fold with desmopressin (noninferiority, P = .04). Exercise-induced improvement in hemostatic parameters including FVIII:C was brief compared with more sustained improvements seen with desmopressin. More than 60% of participants randomized to receive both exercise and desmopressin achieved normal (>50%) FVIII:C, 75 and 135 minutes into the study protocol.

Andexanet Alfa Versus Prothrombin Complex Concentrates/Blood Products as Apixaban/Rivaroxaban Reversal Agents: A Survey Among Pediatric Hematologists.

Direct oral factor Xa inhibitors (DXIs) are approved for use in adult patients with non-valvular heart disease for stroke prevention, and the treatment/prevention of venous thromboembolism (VTE). Recent pediatric clinical trials have demonstrated safety and efficacy of direct oral anticoagulants (DOACs) in the treatment of VTE. However, there is a lack of evidence regarding the use of andexanet alfa and prothrombin complex concentrates (PCC) for anticoagulation reversal of DXIs in the pediatric population. To better understand current DXI reversal strategies in this age group, a 10-question survey was conducted among pediatric hematology members of the Hemostasis and Thrombosis Research Society. Seventeen percent completed the survey (27 of 163 pediatric hematology members) with 74% (n = 20) reporting their use of DXIs for the treatment and prevention of VTE. Forty-four percent (n = 12) would choose andexanet alfa as first-line treatment for life-threatening bleeding while 52% (n = 14) would use PCC first with one individual choosing recombinant factor VII for DXI reversal. Clinical studies of andexanet alfa and PCC for the management of DXI-associated life-threatening bleeding require further investigation in the pediatric population.

Selective modulator of nuclear receptor PPARγ with reduced adipogenic potential ameliorates experimental nephrotic syndrome.

Glomerular disease manifests as nephrotic syndrome (NS) with high proteinuria and comorbidities, and is frequently refractory to standard treatments. We hypothesized that a selective modulator of PPARγ, GQ-16, will provide therapeutic advantage over traditional PPARγ agonists for NS treatment. We demonstrate in a pre-clinical NS model that proteinuria is reduced with pioglitazone to 64%, and robustly with GQ-16 to 81% of nephrosis, comparable to controls. Although both GQ-16 and pioglitazone restore glomerular-Nphs1, hepatic-Pcsk9 and serum-cholesterol, only GQ-16 restores glomerular-Nrf2, and reduces hypoalbuminemia and hypercoagulopathy. GQ-16 and pioglitazone restore common and distinct glomerular gene expression analyzed by RNA-seq and induce insulin sensitizing adipokines to various degrees. Pioglitazone but not GQ-16 induces more lipid accumulation and aP2 in adipocytes and white adipose tissue. We conclude that selective modulation of PPARγ by a partial agonist, GQ-16, is more advantageous than pioglitazone in reducing proteinuria, NS associated comorbidities, and adipogenic side effects of full PPARγ agonists.

Safety and effectiveness of recombinant factor XIII-A2 in congenital factor XIII deficiency: Real-world evidence.

BACKGROUND: Regular factor XIII (FXIII) prophylaxis is standard treatment for congenital FXIII A-subunit deficiency (FXIII-A CD). Recombinant factor XIII-A2 (rFXIII-A2) was extensively evaluated in the mentor trials. OBJECTIVE: To assess real-world safety and treatment effectiveness of rFXIII-A2 prophylaxis from the mentor 6 trial. PATIENTS/METHODS: mentor 6 was a noninterventional, postauthorization safety study investigating rFXIII-A2 prophylaxis in FXIII-A CD. rFXIII-A2 treatment was observed for 2 to 6 years per patient. The primary end point was documentation of adverse drug reactions (including anti-FXIII antibody development). Secondary end points were serious adverse events (SAEs), medical events of special interest (MESIs), and annualized bleeding rate (ABR). RESULTS: Among 30 patients (mean age, 25.5 years), there were 44 adverse events (AEs) (30 mild, 13 moderate, 1 severe). Eleven AEs were possibly/probably related to rFXIII-A2. Of four MESIs, two were unlikely related to rFXIII-A2 (accidental overdose, deep vein thrombosis), and two were possibly/probably related (nonneutralizing anti-FXIII antibody, decreased therapeutic response). All 10 SAEs were unlikely related to rFXIII-A2. Over a follow-up of 75.4 patient-years, there were six treatment-requiring bleeds (all trauma-related with no spontaneous bleeds), giving a treatment-requiring ABR of 0.066; five bleeds were treated successfully with rFXIII-A2. Eight of nine minor surgeries performed during rFXIII-A2 prophylaxis reported successful hemostatic outcomes (one missing evaluation). CONCLUSIONS: These data confirm that rFXIII-A2 prophylaxis is well tolerated as long-term care. There were no spontaneous bleeds, ABR was low, and rFXIII-A2 successfully treated bleeds in patients receiving rFXIII-A2 prophylaxis.

Drive-Through Anticoagulation Clinic During the COVID-19 Pandemic.

An innovative approach to anticoagulation management during the COVID-19 pandemic was used at our center that allowed patients to stay in their vehicle while our anticoagulation advanced practice registered nurse obtained blood for point-of-care international normalized ratio (INR) testing while education and counseling were completed. A significant improvement in the median percentage of INR within the therapeutic range was observed among the patients who used the drive-through clinic. A small group of patients improved compliance to anticoagulation monitoring. Clinical care models, such as this clinic approach may improve patient compliance and adherence to anticoagulation beyond the pandemic needs.

Use of electronic self-administered bleeding assessment tool in diagnosis of paediatric bleeding disorders.

INTRODUCTION: In the era of electronic medical records, pen-and-paper-based physician-administered bleeding assessment tools (BAT) remain under-utilized in the clinical setting, as they are noted to be time-consuming. AIM: The current study reviews the use of an electronic self-administered bleeding assessment tool (eBAT) prospectively in a paediatric haematology clinic and in comparison with a physician administered BAT (pBAT). MATERIALS AND METHODS: This was reviewed and approved in the current form because the aims statement includes the method regarding comparison of 2 groups. So no additional section required. RESULTS: A total of 94 BAT response pairs were available for analysis. The median time required for patients or parents to complete the eBAT was 8 min, with less than a third of the patients requiring over 10 min. The median bleeding scores noted in this study were 4 for both the BATs, with strong positive correlation between the eBAT and the physician administered bleeding questionnaire. The eBAT had a sensitivity of 93.8% (95% CI 82.8%-98.7%), a specificity of 34.8% (95% CI 21.4%-50.3%), a positive predictive value (PV) of 60.0% (95% CI 54.5%-65.2%) and a negative PV of 84.2% (95% CI 62.5%-94.5%) for identifying a bleeding disorder. CONCLUSIONS: Findings indicate that eBAT is a valid and time-efficient screening tool for evaluating patients' bleeding symptoms, which can improve clinical applicability of BATs by reducing time for bleeding history review.

Plasma Cytokine Profiling to Predict Steroid Resistance in Pediatric Nephrotic Syndrome.

INTRODUCTION: Glucocorticoids (GCs) are the primary treatment for nephrotic syndrome (NS), although ∼10% to 20% of children develop steroid-resistant NS (SRNS). Unfortunately, there are no validated biomarkers able to predict SRNS at initial disease presentation. We hypothesized that a plasma cytokine panel could predict SRNS at disease presentation, and identify potential pathways regulating SRNS pathogenesis. METHODS: Paired plasma samples were collected from 26 children with steroid-sensitive NS (SSNS) and 14 with SRNS at NS presentation and after ∼7 weeks of GC therapy, when SSNS versus SRNS was clinically determined. Plasma cytokine profiling was performed with a panel of 27 cytokines. RESULTS: We identified 13 cytokines significantly different in Pretreatment SSNS versus SRNS samples. Statistical modeling identified a cytokine panel (interleukin [IL]-7, IL-9, monocyte chemoattractant protein-1 [MCP-1]) able to discriminate between SSNS and SRNS at disease presentation (receiver operating characteristic [ROC] value = 0.846; sensitivity = 0.643; specificity = 0.846). Furthermore, GC treatment resulted in significant decreases in plasma interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-7, IL-13, and IL-5 in both SSNS and SRNS patients. CONCLUSIONS: These studies suggest that initial GC treatment of NS reduces the plasma cytokines secreted by both CD4+ TH1 cells and TH2 cells, as well as CD8+ T cells. Importantly, a panel of 3 cytokines (IL-7, IL-9, and MCP-1) was able to predict SRNS prior to GC treatment at disease presentation. Although these findings will benefit from validation in a larger cohort, the ability to identify SRNS at disease presentation could greatly benefit patients by enabling both avoidance of unnecessary GC-induced toxicity and earlier transition to more effective alternative treatments.

Nephrotic syndrome disease activity is proportional to its associated hypercoagulopathy.

INTRODUCTION: Nephrotic syndrome (NS) is associated with an acquired hypercoagulopathy that drives its strong predilection for life-threatening thrombosis. We previously demonstrated that hypercoagulopathy is proportional to NS disease severity in animal models. Therefore, hypercoagulopathy and disease severity may inform thrombosis risk and better guide therapeutic decision making. The objective of this study was thus to establish the relationship between disease severity and hypercoagulopathy in human NS. MATERIALS AND METHODS: Thrombin generation assays (TGA) were performed on biorepository plasma samples from a prospective longitudinal NS cohort study. TGA was also determined on a separate cohort of incident NS patients. Multivariable regression was used to build NS-hypercoagulopathy relationship models. RESULTS: Endogenous thrombin potential (ETP) was the TGA parameter most strongly correlated with NS severity and was proportional to conventional measures of NS disease activity including proteinuria, hypercholesterolemia, and hypoalbuminemia. The overall disease activity model was well correlated with ETP (R2 = 0.38). The relationship with disease activity was confirmed in the second cohort. These models further revealed that ETP is related to disease activity in a manner dependent on remission status. CONCLUSION: Consistent with our previously reported animal model observations, we found that the combination of proteinuria, hypercholesterolemia, and hypoalbuminemia correlated with ETP-defined hypercoagulopathy. Hypercoagulopathy improved significantly with partial or complete NS remission. These data are expected to inform studies designed to stratify thrombotic risk for patients with NS.

Protease-activated receptors: An illustrated review.

Proteases are important regulators of cell behavior, survival, and apoptosis. They communicate to cells directly through a special class of G-protein-coupled receptors known as protease-activated receptors (PARs). N-terminal PAR proteolysis unmasks a neo-N-terminus, which serves as a tethered ligand to activate PARs. Using this unique irreversible activation mechanism, PARs relay information across cell membranes. The year 2020 is the 30th year since discovery of the first member of this family, PAR1. In this illustrated review, we highlight achievements in the PAR field over the past 3 decades. Additionally, the known expression profiles of PARs in human tissues and across species are portrayed. We also illustrate the tethered ligand activation mechanism, which is unique to PARs, and PAR regulatory mechanisms. PAR1 was originally named "thrombin receptor" because thrombin was the first protease identified to activate PAR1. However, over the past 30 years, a growing number of proteases have been found to cleave PARs and trigger differential downstream signaling depending on cleavage site, cell type, and species. We exemplify the diversity of PAR1-mediated signaling outcomes in platelets and endothelial cells as pertinent examples to the hemostasis, thrombosis, and vascular biology fields. Further, the termination and regulation of PAR signaling via endocytosis and currently available pharmacologic approaches are depicted. We conclude with portrayal of clinically translational aspects of PAR biology including pharmacologic manipulation and single-nucleotide polymorphisms.

Decreased Bleeding Rates in Patients with Hemophilia A Switching from Standard-Half-Life FVIII to BAY 94-9027 Prophylaxis.

BAY 94-9027 (damoctocog alfa pegol, Jivi) is an extended-half-life recombinant factor VIII (rFVIII) shown to be well-tolerated and efficacious in bleeding prevention in previously treated patients with severe hemophilia A. During the PROTECT VIII study, prophylaxis patients received BAY 94-9027 at intervals determined based on their bleeding phenotype, observed during a 10-week run-in treatment period with twice-weekly dosing. Those with ≤ 1 spontaneous joint or muscle bleed were randomized to either 45 to 60 IU/kg every 5 days or 60 IU/kg every 7 days; patients could increase dosing frequency to every 5 days or twice weekly in the case of bleeds. Those enrolled after the randomization arms were full, and those with ≥ 2 bleeds in the run-in period, received 30 to 40 IU/kg twice weekly. Patients completing the main study could receive open-label BAY 94-9027 in the extension phase. Dosing regimen, total, and joint annualized bleeding rates were analyzed over three periods: prestudy, main study, and extension. A total of 80 patients who were on prophylaxis treatment prior to and during the study and had prior bleed data available were evaluated in this post hoc analysis of PROTECT VIII. Most patients (> 80%) required fewer infusions with BAY 94-9027 prophylaxis versus their previous standard-half-life (SHL) rFVIII product. Lower bleeding and joint bleeding rates were observed over time from the prestudy to the extension study period in all treatment regimens. Compared with SHL FVIII, BAY 94-9027 prophylaxis allows patients to reduce infusion frequency with maintained or improved protection from bleeds.

A pilot randomized trial of atorvastatin as adjunct therapy in patients with acute venous thromboembolism.

Venous thromboembolism (VTE) is the third most common cardiovascular disease and optimizing treatment is essential. In this single-center pilot study, we sought to investigate the effects of statins in addition to anticoagulation in patients with acute VTE. We enrolled patients over 18 with an acute proximal lower extremity deep vein thrombosis with or without pulmonary embolism. Patients were randomized to anticoagulation alone (with either warfarin or rivaroxaban) or anticoagulation and atorvastatin 40 mg daily and followed for 9 months. The primary objective was to determine if adjunct atorvastatin reduced thrombin generation, measured by endogenous thrombin potential and/or peak thrombin concentration. Secondary endpoints included recurrent VTE, arterial thrombosis, bleeding events, lipidomic profiles, and symptoms of post thrombotic syndrome. A total of 21 patients were enrolled (11 anticoagulation only and 10 anticoagulation and atorvastatin) over 3.5 years. Endogenous thrombin potential or peak thrombin was not significantly recued with the addition of atorvastatin. Atorvastatin did significantly reduce the mean LDLs at 3 months, without reduction of either d-dimer or high-sensitivity-C reactive protein. Given the low recruitment rate, continuation of the study was deemed futile and the study was terminated early. Barriers to enrollment and completion of study included the many ineligible patients by exclusion criteria (e.g., preexisting statin use, active malignancy, etc.) and high rate of lost follow-up. The pilot study was terminated early but could inform obstacles for future studies investigating the effects of statins in the management of patients with VTE.