Syndecan-1 Level, a Marker of Endothelial Glycocalyx Degradation, Is Associated With Fetal Exposure to Chorioamnionitis and Is a Potential Biomarker for Early-Onset Neonatal Sepsis.

The goal of this investigation was to identify the association between Syndecan-1 (S1) serum levels in preterm newborns exposed to chorioamnionitis (CA) in utero and the potential of S1 as a biomarker of early-onset neonatal sepsis. A cohort of preterm newborns born <33 weeks gestational age was recruited. Within 48 hours of birth, 0.5 mL of blood was drawn to obtain S1 levels, measured via ELISA. Placentas were examined and classified as having (1) no CA, (2) CA without umbilical cord involvement, or (3) CA with inflammation of the umbilical cord (funisitis). S1 levels were compared between preterm newborns without exposure to CA verus newborns with exposure to CA (including with and without funisitis). Preterm newborns exposed to CA were found to have significantly elevated S1 levels compared to those unexposed. Although S1 levels could not differentiate fetal exposure to CA from exposure to CA with funisitis, the combined CA groups had significantly higher S1 levels compared to those not exposed to CA. S1 level has the potential to become a clinically useful biomarker that could assist in the management of mothers and preterm newborns with CA and funisitis. Furthermore, S1 level could aid in the diagnosis and treatment of early-onset neonatal sepsis.

Andexanet Alfa Neutralizes the Anticoagulant Effects of Unfractionated Heparin of Bovine, Ovine and Porcine Origin Almost as Protamine Sulfate.

INTRODUCTION: Andexanet alfa (AA) - zhzo, recombinant coagulation factor Xa, is an approved antidote for oral Xa inhibitors (apixaban and rivaroxaban). Unfractionated heparin (UFH) is commonly used for therapeutic, interventional, and surgical indications. Protamine sulfate (PrSO4) is frequently used to neutralize UFH. This study aimed to investigate the comparative neutralization profiles of AA and PrSO4 for heparins of bovine, ovine, and porcine origin. MATERIALS AND METHODS: The neutralization effect of PrSO4 at 25 µg/ml and AA at 100 µg/ml was studied on an approximate surgical/interventional concentration of heparin by supplementing whole blood with each of the heparins at 25 µg/ml. For the clotting profile (activated partial thromboplastin time: aPTT), amidolytic (anti-Xa and anti-IIa), and thrombin generation assay each of the heparin were supplemented from -10-0.62 µg/ml. RESULTS: In the whole blood ACT studies, all three heparins produced strong anti-coagulant effects (400-450 seconds) compared to saline (130-150 seconds). Both AA and PrSO4 almost fully neutralized the anti-coagulant effects of heparins (140-160 seconds). Both antidotes completely reversed the anticoagulant effects of all three heparins in the aPTT and thrombin generation assay. However, PrSO4 was more effective in neutralizing the anti-Xa, and anti-IIa effects than AA, which only partially neutralized these effects. CONCLUSION: Andexanet alfa at 100 µg/ml effectively neutralizes the therapeutic and surgical/interventional concentrations of heparins in in-vitro settings. While differences in the anti-Xa, and anti-IIa effects between heparins were noted, anti-coagulant effect of these agents in the aPTT assay were comparable. A similar neutralization profile was observed in the ACT and thrombin generation assays by both agents.

Absolute pharmacokinetics of heparin in primates.

Heparin is a commonly used anticoagulant drug, derived from the tissues of animals including pigs, cows, and sheep. Measuring heparin concentration in plasma is challenging due to its complex molecular structure. Existing methods rely on measuring heparin's anticoagulant activity, which provides pharmacodynamic (PD) data but not pharmacokinetic (PK) data, measuring concentration over time. To overcome this limitation, we used liquid chromatography-mass spectrometry (LC-MS) and the multiple reaction monitoring (MRM) method to directly measure heparin's concentration in non-human primates after administering porcine, bovine, and ovine heparin. A protocol was developed to enable an MRM method for application to small plasma volumes without purification. The PK data obtained from LC-MS are then compared with the data obtained using the Heparin Red assay and the PD data determined using biochemical clinical assays. Results showed that LC-MS and Heparin Red assay measurements closely correlated with unfractionated heparin's biological activities, supporting the use of mass spectra and dye-binding assays to determine heparin levels in plasma. This study builds a way for the measurement of heparin concentration in plasma, which could lead to an improved understanding of heparin's metabolism and dosing safety.

Potency Adjusted Blended Heparin of Bovine, Ovine, and Porcine Heparin Exhibit Comparable Biologic Effects to Referenced Single-Sourced Porcine Heparin.

Introduction: Bovine and ovine mucosa represent alternate anticoagulants to porcine mucosa for production of unfractionated heparin (UFH). Standardized heparins from various sources can be blended and potency adjusted, blended heparins exhibit comparable effects as single-sourced porcine UFH. This study evaluated the pharmacologic profile of blended heparin and compared their activities to that of single sourced porcine, ovine, and bovine heparins. Methods: The anticoagulant effects of gravimetric and potency-adjusted heparins were evaluated with aPTT, TT, anti-Xa, anti-IIa, ACT, and TGA studies. Protamine sulfate studies were used for neutralization potential of each of the individual heparins. Results: The potency-adjusted heparins demonstrated comparable aPTT, TT, anti-Xa, anti-IIa, and ACT values at all concentrations (U/mL). However, in gravimetric studies, bovine heparin consistently showed lower values with the exception of thrombin generation inhibition studies. The protamine sulfate neutralization studies demonstrated complete neutralization at all concentrations for the potency-adjusted heparins. However, at gravimetric concentrations, minor differences were noted in the neutralization profile in each of these heparins. Conclusion: These studies support the hypothesis that blended heparin from bovine, ovine, and porcine tissue, when standardized in unit-equivalent proportions, exhibits a comparable anticoagulant profile to the single species derived heparins.

Enhanced Thrombin Formation in Patients With Ventricular Assist Devices Experiencing Bleeding: Insights From the Multicenter PREVENT Study.

The aim of this investigation was to characterize the hemostatic status of heart failure patients with implanted left ventricular assist devices (LVADs) to propose a mechanism associated with bleeding. Patients (n = 300) from 23 US hospitals were enrolled in the PREVENtion of HeartMate II Pump Thrombosis through Clinical Management (PREVENT) study. A biobank was established with serum and plasma samples prospectively collected from a cohort of 175 patients preimplant baseline (BL) and 3 months (3M) postimplant. Outcomes were collected for 6 months. Thrombin (prothrombin fragment 1.2 [F1.2], functional thrombin generation [TG]) and fibrinolytic activity (D-dimer, plasminogen activator inhibitor-1 [PAI-1]), but not contact activation (complement C5a), were elevated in heart failure patients at BL. F1.2, TG, and PAI-1 levels decreased 3M after LVAD implantation ( p < 0.01) but did not revert to normal in all patients; conversely, D-dimer increased BL to 3M ( p < 0.01). Compared with patients without events, thrombin activity (F1.2) was increased in patients with late bleeding (3-4 months postimplant) ( p = 0.06) and in those with late gastrointestinal (GI) bleeding ( p = 0.01). Patients with 3M F1.2 levels above the cohort mean had a higher incidence of bleeding ( p < 0.001) and GI bleeding ( p < 0.001) compared with those with below mean F1.2. Patients experiencing multiple bleeding events were more likely to have 3M F1.2 greater than the cohort mean. Despite anticoagulation with aspirin and warfarin, LVAD implanted patients exhibit hemostatic activation. Excess thrombin formation, particularly shown by increased F1.2, was demonstrated in association with bleeding in LVAD implanted patients.

Differential Neutralization of Apixaban, Betrixaban, Edoxaban, and Rivaroxaban by Andexanet Alfa as Measured by Whole Blood Thromboelastographic Analysis.

INTRODUCTION: The available oral anti-Xa agents are routinely used for the management of thrombotic disorders. A molecularly modified recombinant coagulation FXa, also known as Andexanet Alfa (AA), that has been developed as an antidote to neutralize the bleeding effects of oral FXa inhibitors, such as Apixaban and Rivaroxaban. MATERIALS AND METHODS: This study utilized thromboelastography (TEG 5000 Hemostasis System), to investigate the neutralizing effects of AA at different concentrations of oral FXa inhibitors measuring such parameters as R-Time, K-Time, Angle, and Max Amplitude (MA). Apixaban, Betrixaban, Edoxaban, and Rivaroxaban were obtained commercially in powdered form. Each of these drugs was supplemented with freshly drawn whole citrated blood at a concentration of 1 µg/mL. And subsequently mixed with AA at 50 or 100 µg/mL. RESULTS: At a concentration of 1 µg/mL, all FXa inhibitors produced variable anticoagulant effects in the order of Edoxaban > Betrixaban > Rivaroxaban > Apixaban. AA at 100 µg/mL produced a complete neutralization of these inhibitors whereas at 50 µg/mL relatively weaker neutralization as measured by various parameters. CONCLUSION: These results suggest that regardless of the variable anticoagulant effects exhibited by the FXa Inhibitors, AA at FC = 100 µg/mL fully neutralized these agents as measured by the TEG parameters. AA was shown to be more effective in neutralizing Betrixaban and least effective in Apixaban. The neutralization of various FXa inhibitors was dose and donor-dependent warranting dosage adjustment for optimal outcomes.

Inflammatory cytokines in robot-assisted thoracic surgery versus video-assisted thoracic surgery.

Background: Cytokines play a crucial role in the inflammatory response and are essential modulators of injury repair mechanisms. While minimally invasive operations have been shown to induce lower levels of cytokines compared to open thoracotomy, the inflammatory cytokine profile difference between video-assisted (VATS) and robotic-assisted thoracic surgery (RATS) techniques has yet to be elucidated. Methods: In this prospective observational study of 45 patients undergoing RATS (n=30) or VATS (n=15) lung resection for malignancy, plasma levels of interleukin (IL)-1α, IL-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, vascular endothelial growth factor (VEGF), interferon (IFN)-γ, tumor necrosis factor (TNF)-α, monocyte chemo-attractant protein (MCP)-1, and endothelial growth factor (EGF) were measured before and after surgery via immunoassay. Results: Levels of IL-6 and MCP-1 were significantly higher in patients undergoing VATS than in patients undergoing RATS (P<0.001 and P=0.005, respectively) 2 hours following surgery. MCP-1 levels were also found to be significantly higher in the VATS group (P<0.001) 24 hours following surgery. IL-1α, IL-1ß, IL-2, IL-4, IL-8, IL-10, IFN-γ, TNF-α, and EGF levels were not significantly different at any time-point comparing VATS to RATS. Conclusions: The VATS approach is associated with a more robust pro-inflammatory cytokine response through the upregulation of MCP-1 and IL-6 when compared to the RATS approach in patients undergoing anatomic lung resection. Further studies are necessary to validate the clinical significance of this finding.

The Multistage Antimalarial Compound Calxinin Perturbates P. falciparum Ca2+ Homeostasis by Targeting a Unique Ion Channel.

Malaria elimination urgently needs novel antimalarial therapies that transcend resistance, toxicity, and high costs. Our multicentric international collaborative team focuses on developing multistage antimalarials that exhibit novel mechanisms of action. Here, we describe the design, synthesis, and evaluation of a novel multistage antimalarial compound, 'Calxinin'. A compound that consists of hydroxyethylamine (HEA) and trifluoromethyl-benzyl-piperazine. Calxinin exhibits potent inhibitory activity in the nanomolar range against the asexual blood stages of drug-sensitive (3D7), multidrug-resistant (Dd2), artemisinin-resistant (IPC4912), and fresh Kenyan field isolated Plasmodium falciparum strains. Calxinin treatment resulted in diminished maturation of parasite sexual precursor cells (gametocytes) accompanied by distorted parasite morphology. Further, in vitro liver-stage testing with a mouse model showed reduced parasite load at an IC50 of 79 nM. A single dose (10 mg/kg) of Calxinin resulted in a 30% reduction in parasitemia in mice infected with a chloroquine-resistant strain of the rodent parasite P. berghei. The ex vivo ookinete inhibitory concentration within mosquito gut IC50 was 150 nM. Cellular in vitro toxicity assays in the primary and immortalized human cell lines did not show cytotoxicity. A computational protein target identification pipeline identified a putative P. falciparum membrane protein (Pf3D7_1313500) involved in parasite calcium (Ca2+) homeostasis as a potential Calxinin target. This highly conserved protein is related to the family of transient receptor potential cation channels (TRP-ML). Target validation experiments showed that exposure of parasitized RBCs (pRBCs) to Calxinin induces a rapid release of intracellular Ca2+ from pRBCs; leaving de-calcinated parasites trapped in RBCs. Overall, we demonstrated that Calxinin is a promising antimalarial lead compound with a novel mechanism of action and with potential therapeutic, prophylactic, and transmission-blocking properties against parasites resistant to current antimalarials.

Predictive Role of Blood Cellular Indices and Their Relationship with Endogenous Glycosaminoglycans as Determinants of Inflammatory Biomarkers in Pulmonary Embolism.

INTRODUCTION: In this study, we profiled the levels of blood cellular indices, endogenous glycosaminoglycans (GAGs) and inflammatory biomarkers in a cohort comprised of pulmonary embolism (PE) patients, to determine their inter-relationships. Identification of this relationship may provide insight to the complex pathophysiology of PE and the predictive role of blood cellular indices in acute PE patients. MATERIALS AND METHODS: Plasma samples from PE patients and healthy controls were analyzed for thrombo-inflammatory biomarkers (IL-2, IL-4, IL-6, IL-8, IL-10, VEGF, IFN-É£, TNF-α, IL-1α, IL-1ß, MCP-1, EGF, D-dimer, CRP and MMP-9) using biochip array and ELISA methods. The endogenous GAG levels were quantified using a fluorescence quenching method. The data regarding the blood cellular indices were collected through the review of patient medical records and analyzed to demonstrate their relationship. RESULTS: The levels of inflammatory biomarkers and endogenous GAGs were elevated in acute PE patients compared to controls (P < .05). Most of the blood cellular indices have shown significant differences in acute PE patients compared to controls (P < .05). The levels of inflammatory biomarkers, endogenous GAGs and the blood cellular indices have shown significant associations in correlation and multivariable analysis. While NLR, PLR and SII were significantly predicting the 30-day mortality, PNR, ELR and EMR were not sufficient to predict 30-day mortality in acute PE. CONCLUSION: Our results show that the increased thrombo-inflammatory response is associated with the release of GAGs and the changes in blood cellular indices. The predictive role of the blood cellular indices for mortality is dependent on their relationship with the inflammatory response.

Differential Neutralization of Unfractionated Heparin and Enoxaparin by Andexanet Alfa.

INTRODUCTION: Andexanet alfa (andexanet) is an approved antidote used to reverse the bleeding effects of Direct Oral Anticoagulant (Direct-Xa agents) agents because it reverses anti-Xa activity. Unfractionated heparin (UFH) and low molecular weight heparins (LMWHs) exhibit anti-Xa activity. The purpose is to investigate the neutralization of UFH and LMWH by andexanet in activated clotting time (ACT), thrombelastography (TEG), and anti-Xa due to the protamine sulfate shortage. METHODS: UFH and LMWH were studied with andexanet, PS, or saline as potential reversal agents/controls at varying concentrations in ACT, TEG, and anti-Xa and compared to each other. RESULTS: Andexanet partially neutralized both drugs several TEG parameters at high andexanet concentrations, but it was not as effective as protamine sulfate in any of the assays used. Most TEG parameters were correlated with andexanet concentration. In ACT, significant neutralization was demonstrated at many andexanet concentrations for UFH, but not LMWH. UFH was completely neutralized by PS in ACT, while LMWH was partially neutralized by PS in ACT. Andexanet alfa was a less effective neutralization agent than the protamine sulfate as it only partially neutralized UFH in ACT and was ineffective at neutralizing LMWH when tested at the same concentration as PS (10 ug/mL). CONCLUSION: Andexanet partially neutralized UFH and LMWH with variability between assays, necessitating investigation into assay-dependent differences.

Potential Anti-SARS-CoV-2 Activity of Pentosan Polysulfate and Mucopolysaccharide Polysulfate.

With the increased prevalence of new SARS-CoV-2 variants of concern, such as Delta and Omicron, the COVID-19 pandemic has become an ongoing human health disaster, killing millions worldwide. SARS-CoV-2 invades its host through the interaction of its spike (S) protein with a host cell receptor, angiotensin-converting enzyme 2 (ACE2). In addition, heparan sulfate (HS) on the surface of host cells plays an important role as a co-receptor for this viral pathogen-host cell interaction. Our previous studies demonstrated that many sulfated glycans, such as heparin, fucoidans, and rhamnan sulfate have anti-SARS-CoV-2 activities. In the current study, a small library of sulfated glycans and highly negatively charged compounds, including pentosan polysulfate (PPS), mucopolysaccharide polysulfate (MPS), sulfated lactobionic acid, sulodexide, and defibrotide, was assembled and evaluated for binding to the S-proteins and inhibition of viral infectivity in vitro. These compounds inhibited the interaction of the S-protein receptor-binding domain (RBD) (wild type and different variants) with immobilized heparin, a highly sulfated HS, as determined using surface plasmon resonance (SPR). PPS and MPS showed the strongest inhibition of interaction of heparin and S-protein RBD. The competitive binding studies showed that the IC50 of PPS and MPS against the S-protein RBD binding to immobilized heparin was ~35 nM and ~9 nM, respectively, much lower than the IC50 for soluble heparin (IC50 = 56 nM). Both PPS and MPS showed stronger inhibition than heparin on the S-protein RBD or spike pseudotyped lentiviral particles binding to immobilized heparin. Finally, in an in vitro cell-based assay, PPS and MPS exhibited strong antiviral activities against pseudotyped viral particles of SARS-CoV-2 containing wild-type or Delta S-proteins.

Analysis of 3-O-Sulfated Heparan Sulfate Using Isotopically Labeled Oligosaccharide Calibrants.

The 3-O-sulfated glucosamine in heparan sulfate (HS) is a low-abundance structural component, but it is a key saccharide unit for the biological activities of HS. A method to determine the level of 3-O-sulfated HS is lacking. Here, we describe a LC-MS/MS based method to analyze the structural motifs. We determined the levels of 3-O-sulfated structural motifs from pharmaceutical heparin manufactured from bovine, porcine, and ovine. We discovered that saccharide chains carrying 3-O-sulfation from enoxaparin, an FDA-approved low-molecular weight heparin, displayed a slower clearance rate than non-3-O-sulfated sugar chains in a mouse model. Lastly, we detected the 3-O-sulfated HS from human brain. Furthermore, we found that a specific 3-O-sulfated structural motif, tetra-1, is elevated in the brain HS from Alzheimer's disease patients (n = 5, p = 0.0020). Our method offers a practical solution to measure 3-O-sulfated HS from biological sources with the sensitivity and quantitative capability.

An Update on the Status of Vaccine Development for SARS-CoV-2 Including Variants. Practical Considerations for COVID-19 Special Populations.

The progress in the development of various vaccine platforms against SARS-CoV-2 have been rather remarkable owing to advancement in molecular and biologic sciences. Most of the current vaccines and those in development focus on targeting the viral spike proteins by generating antibodies of varying spectrum. These vaccines represent a variety of platforms including whole virus vaccines, viral vector vaccines, nucleic acid vaccines representing RNA, DNA, and their hybrid forms.The therapeutic efficacy of these vaccines varies owing to their pharmacodynamic individualities. COVID-19 variants are capable of inducing different pathologic responses and some of which may be resistant to antibodies generated by current vaccines. The current clinical use of these vaccines has been through emergency use authorization until recently. Moreover, the efficacy and safety of these vaccines have been tested in substantial numbers of individuals but studies in special populations that better reflect the global population are pending results. These specialized populations include young children, immunocompromised patients, pregnant individuals, and other specialized groups. Combination approaches, molecularly modified vaccination approaches, and vaccines conferring longer periods of immunity are being currently being investigated, as well as pharmacovigilance studies.The continual transformation of SARS-CoV-2 and its variants are of concern along with the breakthrough infections. These considerations pose new challenges for the development of vaccination platforms. For this purpose, booster doses, combination vaccine approaches, and other modalities are being discussed. This review provides an updated account of currently available vaccines and those in advanced development with reference to their composition and mechanisms of action.A discussion on the use of vaccines in special populations including immunocompromised patients, pregnant women and other specialized populations are also included.

Multiplex genome editing of mammalian cells for producing recombinant heparin.

Heparin is an essential anticoagulant used for treating and preventing thrombosis. However, the complexity of heparin has hindered the development of a recombinant source, making its supply dependent on a vulnerable animal population. In nature, heparin is produced exclusively in mast cells, which are not suitable for commercial production, but mastocytoma cells are readily grown in culture and make heparan sulfate, a closely related glycosaminoglycan that lacks anticoagulant activity. Using gene expression profiling of mast cells as a guide, a multiplex genome engineering strategy was devised to produce heparan sulfate with high anticoagulant potency and to eliminate contaminating chondroitin sulfate from mastocytoma cells. The heparan sulfate purified from engineered cells grown in chemically defined medium has anticoagulant potency that exceeds porcine-derived heparin and confers anticoagulant activity to the blood of healthy mice. This work demonstrates the feasibility of producing recombinant heparin from mammalian cell culture as an alternative to animal sources.

An Update on the Pathogenesis of COVID-19 and the Reportedly Rare Thrombotic Events Following Vaccination.

Today the coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has become a global health problem. After more than a year with the pandemic, although our knowledge has progressed on COVID-19, there are still many unknowns in virological, pathophysiological and immunological aspects. It is obvious that the most efficient solution to end this pandemic are safe and efficient vaccines. This manuscript summarizes the pathophysiological and thrombotic features of COVID-19 and the safety and efficacy of currently approved COVID-19 vaccines with an aim to clarify the recent concerns of thromboembolic events after COVID-19 vaccination. The influx of newer information is rapid, requiring periodic updates and objective assessment of the data on the pathogenesis of COVID-19 variants and the safety and efficacy of currently available vaccines.

Protamine Sulfate Neutralization Profile of Various Dosages of Bovine, Ovine and Porcine UFHs and Their Depolymerized Derivatives in Non-Human Primates.

INTRODUCTION: Currently used unfractionated heparins (UFHs) and low molecular weight heparins (LMWHs) are derived from porcine intestinal mucosa. However, heparins have also been manufactured from tissues of other mammalian species such as cow (Bovine) and sheep (Ovine). Protamine sulphate (PS) is an effective inhibitor of heparin and is used clinically to neutralize both LMWH and UFH. In this study, we determined the PS neutralization profile of these agents in non-human primate model using anti-Xa and anti-IIa methods. MATERIAL AND METHODS: UFHs obtained from bovine, ovine and porcine mucosal tissues and their respective depolymerized LMWHs were administered at both, gravimetric (0.5 mg/kg) and potency adjusted (100 U/kg) dosages regimen intravenously to individual groups of primates in cross over studies. PS was administered at a fixed dosage and the relative neutralization of these anticoagulants was measured utilizing amidolytic anti-Xa and anti-IIa methods. RESULTS: These studies have demonstrated that, the equi-gravimetric dosages of BMH, PMH and OMH have comparable PS neutralization profiles. At potency adjusted dosages, all UFHs were completely neutralized by PS. Although comparable, the LMWHs were not fully neutralized by PS in both the anti-Xa and anti-IIa assays. PS was more efficient in neutralizing the anti-IIa effects of LMWHs. CONCLUSION: Heparins of diverse origins showed comparable neutralization profiles by PS in the amidolytic anti-Xa and anti-IIa assays.

Studies on Tissue Factor Pathway Inhibitor Antigen Release by Bovine, Ovine and Porcine Heparins Following Intravenous Administration to Non-Human Primates.

Unfractionated heparin (UFH) is a sulfated glycosaminoglycan that consists of repeating disaccharides, containing iduronic acid (or glucuronic acid) and glucosamine, exhibiting variable degrees of sulfation. UFHs release tissue factor pathway inhibitor (TFPI) which inhibits the extrinsic pathway of coagulation by inactivating factor Xa and the factor VIIa/TF complex. Most heparins used clinically are derived from porcine intestinal mucosa however, heparins can also be derived from tissues of bovine and ovine origin. Currently there are some concerns about the shortage of the porcine heparins as they are widely used in the manufacturing of the low molecular weight heparins (LMWHs). Moreover, due to cultural and religious reasons in some countries, alternative sources of heparins are needed. Bovine mucosal heparins (BMH) are currently being developed for re-introduction to the US market for both medical and surgical indications. Compared to porcine mucosal heparin (PMH), BMH exhibits a somewhat weaker anti-coagulant activity. In this study, we determined the TFPI antigen level following administration of various dosages of UFHs from different origins. These studies demonstrated that IV administration of equigravemetric dosages of PMH and ovine mucosal heparin (OMH) to non-human primates resulted in comparable TFPI antigen release from endothelial cells. In addition, the levels of TFPI were significantly higher than TFPI antigen levels observed after BMH administration. Potency adjusted dosing resulted in comparable TFPI release profiles for all 3 heparins. Therefore, such dosing may provide uniform levels of anticoagulation for the parenteral indications for UFHs. These observations warrant further clinical validation in specific indications.

Comparative Anticoagulant and Thrombin Generation Inhibitory Profile of Heparin, Sulodexide and Its Components.

INTRODUCTION: Sulodexide represents a mixture of fast-moving heparin (FMH) and dermatan sulfate (DS) and has been used for the management of venous diseases such as DVT and related disorders. The purpose of this study is to compare sulodexide and its components with unfractionated heparin (UFH) to determine its suitability for the indications in which UFH is used. MATERIALS AND METHOD: Active pharmaceutical ingredients (API) versions of sulodexide, FMH and DS were obtained from Alfasigma. API versions of UFH were obtained from Medefil Inc. Normal human citrated plasma was obtained from blood bank of the Loyola University Medical Center. Each of the individual agents were supplemented in plasma at a graded concentration of 0.0-10 µg/mL. Clotting assays (PiCT, aPTT, PT and TT), anti-Xa and anti-IIa and thrombin generation studies were carried out. Results were compiled as mean ± SD of 3 individual determination. RESULT: In the clot based (PiCT, aPTT and TT), anti-Xa and IIa assays, both the UFH and FMH produced stronger activities in these assays followed by sulodexide. DS did not show any anticoagulant activity. In the thrombin generation assay, FMH and UFH produced comparable inhibition of thrombin generation as measured by various parameters. Sulodexide was slightly weaker in this assay, whereas DS produced relatively weaker effects. CONCLUSION: In comparison to sulodexide, both UFH and FMH exhibit comparable anticoagulant activity despite differences in their molecular weight. These results suggest that sulodexide can be developed as a parenteral anticoagulant for indications in which UFH is used.

Protein C Pathway, Inflammation, and Pump Thrombosis in Patients With Left Ventricular Assist Devices.

Use of left ventricular assist devices (LVADs) for management of advanced heart failure is becoming increasingly common; however, device associated thrombosis remains an important cause of mortality in this patient population. We hypothesize that inflammation in LVAD implanted patients dysregulates the protein C pathway, creating a hypercoagulable state leading to thrombosis. Plasma samples from 22 patients implanted with the Thoratec HeartMate II LVAD were analyzed by commercial ELISAs. Retrospective sample selection included those collected 1-3 months prior to and within 1 month after a thrombotic or bleeding event. Unrelated to warfarin dosing, total protein S and free protein S (p = 0.033) levels were 20% lower in patients with LVAD-thrombosis than in patients with LVAD-bleeding. Levels of protein C, soluble endothelial cell protein C receptor, and soluble thrombomodulin were similar in both groups before and after the event. Compared to normal, C-reactive protein levels were 25-fold elevated in LVAD-thrombosis patients but only 9-fold elevated in LVAD-bleeding patients. This study suggests that protein S, influenced by the inflammatory state, is a gatekeeper for the function of protein C in patients with LVAD-associated thrombosis.