Thrombus Formation Research Articles

Alteplase in COVID-19 severe hypoxemic respiratory failure: the TRISTARDS multicenter randomized trial

BackgroundPulmonary intravascular thrombus formation has been widely observed in patients with respiratory failure, for example, in patients with SARS-CoV-2 infection (COVID-19). The aim of this study was to evaluate the efficacy/safety of alteplase thrombolysis in COVID-19 severe hypoxemic respiratory failure. In this multicenter, open-label study, patients were randomized to receive alteplase (low- or high-dose) over 5 days plus standard of care (SOC), or SOC alone. The primary endpoint was time to clinical improvement (≥ 2-point decrease on WHO Clinical Progression Scale, or hospital discharge) up to Day 28. Secondary endpoints included all-cause mortality at Day 28, treatment failure at Day 28 and change in arterial oxygen partial pressure/fractional inspired oxygen (PaO2/FiO2) ratio at Day 6 versus baseline.ResultsSixty-nine patients were randomized to alteplase (low- or high-dose) and 35 to SOC; 65% were on high-flow oxygen or non-invasive ventilation at baseline. Median time to clinical improvement was 25 days in the alteplase group and > 28 days (median not reached) in the SOC group. All-cause mortality was 8/69 (12%) versus 10/35 (29%) in the alteplase versus SOC groups, respectively (unadjusted risk difference [RD], − 17% [95% confidence interval (CI) − 34 to 0], p = 0.047; adjusted RD, − 16% [95% CI − 31 to 1], p = 0.058). The PaO2/FiO2 ratio (mean [standard deviation]) increased by + 30 (84) mmHg in the alteplase group and decreased by − 12 (59) mmHg in the SOC group (adjusted mean difference vs. SOC, p = 0.052). Differences were greater in patients receiving high-dose alteplase, and in those not receiving invasive ventilation. Eighteen patients (26.1%) in the alteplase group discontinued treatment due to adverse events. Major bleeding was more frequent with alteplase than with SOC (9 vs. 0 patients); no bleeding was fatal. The study closed early due to insufficient patient recruitment.ConclusionAlteplase was not associated with faster clinical recovery from COVID-19 severe hypoxemic respiratory failure. A numerical difference in survival and PaO2/FiO2 ratio was observed, particularly in patients not receiving invasive ventilation. These exploratory findings merit further investigation in larger patient cohorts that are adequately powered to confirm the hypotheses generated in this study regarding the impact of alteplase on treatment outcomes.Trial registration ClinicalTrials.gov: NCT04640194 (November 23, 2020); https://clinicaltrials.gov/study/NCT04640194 (early discontinuation due to insufficient patient recruitment).

Cure of Congenital Purpura Fulminans via Expression of Engineered Protein C Through Neonatal Genome Editing in Mice.

PC (protein C) is a plasma anticoagulant encoded by PROC; mutation in both PROC alleles results in neonatal purpura fulminans-a fatal systemic thrombotic disorder. In the present study, we aimed to develop a genome editing treatment to cure congenital PC deficiency. We generated an engineered APC (activated PC) to insert a furin-cleaving peptide sequence between light and heavy chains. The engineered PC was expressed in the liver of mice using an adeno-associated virus vector or CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9)-mediated genome editing using an adeno-associated virus vector in vivo. The engineered PC could be released in its activated form and significantly prolonged the plasma coagulation time independent of the cofactor activity of PS (protein S) in vitro. The adeno-associated virus vector-mediated expression of the engineered PC, but not wild-type PC, prolonged coagulation time owing to the inhibition of activated coagulation FV (factor V) in a dose-dependent manner and abolished pathological thrombus formation in vivo in C57BL/6J mice. The insertion of EGFP sequence conjugated with self-cleaving peptide sequence at Alb locus via neonatal in vivo genome editing using adeno-associated virus vector resulted in the expression of EGFP in 7% of liver cells, mainly via homology-directed repair, in mice. Finally, we succeeded in improving the survival of PC-deficient mice by expressing the engineered PC via neonatal genome editing in vivo. These results suggest that the expression of engineered PC via neonatal genome editing is a potential cure for severe congenital PC deficiency.

Mitigation of Oxidized Oil Effects on Production Performances and Meat Quality of Broilers by Dietary Supplementation of Allicin

The objective of this study was to evaluate the effects of dietary oxidized oil and allicin (two different dietary sources) as natural antioxidants on the growth performance and meat quality of broilers. A total of 200 one-day-old Ross 308 broilers were randomly divided into four dietary groups (50 birds/group). The experimental groups (OO—oxidized oil; OOA—oxidized oil and allicin; OOG—oxidized oil and garlic leaves) differed from the control one by the presence of oxidized oil in their dietary structure (peroxide value 9.07 (OO, OOA and OOG groups) vs. 1.70 (C group) meq active oxygen/kg). The diets given to the experimental groups differed from each other by the presence of allicin (100 mg/kg inclusion rate as extract (OOA) and 0.5% as garlic leaf powder (OOG)). At the end of the experiment, six animals/group were slaughtered, meat samples (breast and thigh) were collected, and nutritional value was established. The results showed that the allicin included in the experimental diet did not influence the proximate composition of breast meat (crude protein, fat, ash, and dry matter). The fatty acid profile was determined for each group of samples; a significant decrease in omega 3 FAs was noticed between the C group and the E groups (3.27% vs. 1.46%, 1.60%, and 1.56%) in breast meat samples, and a corresponding increase was noticed in saturated fatty acid (SFA) concentrations. Health indices with implications for atheroma and thrombus formation and cholesterol level were negatively affected by the presence of oxidized oil in the experimental diets, but the allicin extract supplement appeared to mitigate its influence. A positive influence of the dietary supplement was noticed on antioxidant capacity and polyphenol concentrations determined in breast and thigh samples under allicin supplement influence. The results of the current study revealed that the use of low oxidized oil in broilers diets did not affect productive performance. The nutritional quality of meat (breast and thigh) was negatively influenced by the presence of oxidized oil, but allicin supplements (extract or garlic leaves) improved lipid quality indices and antioxidant potential.

Blockade of the Platelet-Driven CXCL7-CXCR1/2 Inflammatory Axis Prevents Murine Cerebral Aneurysm Formation and Rupture.

Platelet aggregation is intimately associated with vascular inflammation and is commonly seen on routine histology studies of cerebral aneurysms. Platelets, when activated, have been shown to augment neutrophil response and the pro-inflammatory cascade. Platelet-neutrophil complexes have been found to aggravate atherosclerosis through a positive feedback loop. We hypothesized that targeting platelet aggregation and downstream inflammation could be used to prevent aneurysm formation and progression. First, we induced cerebral aneurysm formation in a previously described intracranial aneurysm model via carotid artery ligation, hypertension, and stereotactic elastase injection in C57BL/6 mice and analyzed vessels for lesion and thrombus formation. Raybiotech cytokine arrays were used to analyze 96 cytokines in induced murine aneurysms and 120 cytokines in human tissue samples. Cerebral aneurysm formation and inflammatory pathway were then studied in animals treated with IgG2 antibody (control), anti-GpIb antibody (platelet depletion), 1:10 DMSO:PBS (control), clopidogrel, anti-CXCR1/2 small molecule inhibitor, or anti-CXCL7 antibody. Bleeding assays and flow cytometry were used to evaluate platelet function in treated groups. CD31 + platelet aggregates are a common feature in human and mouse cerebral aneurysm specimens. Platelet ablation in mice prevents cerebral aneurysm formation (20% vs 100% in control antibody-treated mice, n = 5 each, p = 0.0476). Mice treated with 1mg/kg clopidogrel develop significantly less aneurysms than controls (18% vs 73%, n = 11 and 11, respectively, p = 0.03). Semi-quantitative analysis of 96 different cytokines using Raybiotech arrays shows increased protein expression of CXCL7 in murine cerebral aneurysms when compared to controls. Treatment with clopidogrel results in reciprocal decrease in detected CXCL7. Targeting CXCL7-CXCR1/2 axis with 10mg/kg reparixin (CXCR1/2 antagonist) significantly decreases cerebral aneurysm formation (11% vs 73%, n = 9 and 11, p = 0.0098) while treatment with 10mg/kg SB225002 tends to decrease aneurysm formation (36% vs 73%, n = 11 vs n = 7, p = 0.11). Lastly, specific antibody blockade against CXCL7 using anti-CXCL7 antibody at 100 ug/mL significantly decreases cerebral aneurysm formation (29% vs 75%, n = 7 vs n = 8, p = 0.046). Platelet inflammation has an important role in cerebral aneurysm formation. Small molecule inhibitors targeting platelet CXCL7-CXCR1/2 inflammatory axis could be used to prevent cerebral aneurysm formation or progression.

Modeling Fibrin Accumulation on Flow-Diverting Devices for Intracranial Aneurysms.

The mechanisms leading to aneurysm occlusion after treatment with flow-diverting devices are not fully understood. Flow modification induces thrombus formation within the aneurysm cavity, but fibrin can simultaneously accumulate and cover the device scaffold, leading to further flow modification. However, the interplay and relative importance of these processes are not clearly understood. A computational model of fibrin accumulation and flow modification after flow diversion treatment of cerebral aneurysms has been developed under the guidance of invitro experiments and observations. The model is based on the loose coupling of flow and transport-reaction equations that are solved separately by independent codes. Interaction or reactive terms account for thrombin production from prothrombin stimulated by thrombogenic metallic wires and inhibition by antithrombin as well as fibrin production from fibrinogen stimulated by thrombin and flow shear stress, and fibrin adhesion to device wires and already attached fibrin. The computational model was demonstrated and tested on idealized vessel and aneurysm geometries. The model was able to reproduce the salient features of fibrin accumulation after the deployment of flow-diverting devices in idealized invitro models of cerebral aneurysms. Namely, fibrin production in regions of high shear stress, initial accumulation at the inflow zone, and progressive occlusion of the device and corresponding flow attenuation. The computational model linking flow dynamics to fibrin production, transport, and adhesion can be used to investigate and better understand the effects that lead to fibrin accumulation and the resulting aneurysm inflow reduction and intra-aneurysmal flow modulation.

Measurement of platelet thrombus formation in patients following severe thermal injury

Severe thermal injury significantly impacts upon hemostasis and is associated with classical changes to the circulating platelet count with a nadir followed by a rebound thrombocytosis at days ~3 and ~15 post-injury, respectively. To date, few studies have assessed platelet function following thermal injury as platelet tests often require large quantities of blood, are not representative of normal platelet pathophysiology, and are usually dependent on a normal platelet count. The purpose of this study was to measure platelet thrombus formation in vitro using a whole blood flow chip-based system following thermal injury and to study how platelet counts may impact upon the measurement. Adult (≥16 years) patients (N = 10) with ≥ 20% total burn surface area (TBSA) burn were recruited within 24 h of injury. Healthy controls (N = 25) were also recruited. Whole blood counts were measured using a hematology analyzer (Sysmex XN-1000). Platelet function was measured using the Total Thrombus-formation Analyzer System (T-TAS) within chips coated with tissue factor and collagen at shear rates of either 600 sec−1 (AR chips) or 1200 sec−1 (HD chips), the latter test being independent of platelet count. We confirmed the classical nadir in platelet counts following severe thermal injury at days 2, 3, 4 (p < 0.0001) and day 5 (p < 0.01) post-injury compared to healthy controls. Physiological platelet thrombus formation was significantly (p < 0.01) abnormal at day 3 post-injury using the AR chips but was related to the platelet count. However, although platelet dysfunction was not significant using HD chips, some of the results were independent of platelet count. A small number of samples, however, still gave abnormal results suggesting that there can be an underlying acquired platelet functional abnormality. Furthermore, the AR chip Area Under the Curve (AUC) was significantly lower on day 1 post-injury and negatively associated with severity of injury (TBSA, p < 0.05) and higher platelet function (AUC) positively associated with survival (p < 0.05). This study suggests that measuring platelet dysfunction within a more physiological in vitro test may have potential clinical utility. Larger studies are required to fully understand the impact of platelet dysfunction following severe thermal injury.

How I do It: High flow EC-IC bypass for complex middle cerebral artery aneurysms using the lateral circumflex femoral artery as interposition graft.

High-flow bypasses with parent vessel occlusion are required for complex aneurysms originating from the ICA or MCA. Traditional graft options are the saphenous vein however, it has a higher rate of thrombus formation than an arterial graft. The radial artery is commonly used, however, tapers in its distal course and is contraindicated in some patients while the lateral circumflex femoral artery is an excellent graft vessel and easy to harvest. We present our technique and experience harvesting the lateral circumflex femoral artery as an alternative graft vessel for high-flow bypasses. The lateral circumflex femoral artery is easy to harvest and is a reliable graft vessel for high-flow bypasses for complex aneurysms.

Renal involvement in TAFRO syndrome: a review.

Renal involvement in TAFRO syndrome is characterized clinically by general edema with ascites and pleural effusions and a rapidly progressive decline in renal function, with urinary protein levels of usually less than 1g/day. The histologic features of the kidneys can be described as glomerular microangiopathy characterized by mesangiolysis or mesangial loosening, endothelial cell proliferation, edematous opening in the subendothelial space, and glomerular basement membrane (GBM) doubling due to newly formed basement membrane. Findings such as rupture of the GBM, foot-process effacement or fusion, and epithelial cell loss are rare, and thrombus formation is difficult to identify in the glomerulus. Furthermore, immunodeposits are not seen on immunofluorescence staining or electron microscopy. Unlike adults, in addition to the glomerular lesions described above, adolescents appear to show intimal proliferation of the arterioles and interlobular arteries to the vascular poles and occlusion of the vascular lumen.

Platelet-activating Factor (PAF) in Urinary Bladder Smooth Muscle (UBSM): Its Novel Role as a Potential Inducer of Detrusor Overactivity and the Mechanisms Underlying Its Effects in Enhancing UBSM Mechanical Activities

Platelet-activating factor (PAF), a phospholipid mediator, was discovered in 1972 as an inducer of platelet aggregation. Subsequent studies have revealed that PAF has a variety of biological functions, such as its role as a potent proinflammatory mediator. Additionally, PAF regulates the contractile functions of various types of smooth muscle (SM), such as the (1) endothelium-dependent relaxation of vascular SM; (2) contraction and epithelium-dependent relaxation of airway SM; (3) contraction of gastrointestinal SM; and (4) contraction of uterine SM, which occurs more strongly in pregnant females. PAF is produced in platelets, monocytes, neutrophils, and macrophages, which are cells related to thrombus formation and inflammation/immune responses. Furthermore, PAF is produced in various other cells throughout the body. Interestingly, recent studies have focused on the urinary bladder (UB) as a PAF-producing organ since the accumulation of this phospholipid is enhanced in patients with bladder cancer and interstitial cystitis/bladder pain syndrome, especially those who smoke. Therefore, in UB tissue, PAF may play a substantial role as an inducer or enhancer of cancers and inflammatory diseases. However, the effects of PAF on the immediate mechanical activities of UBSM have not been investigated to date. In this regard, we recently discovered that PAF strongly enhances mechanical activities (muscle tone and spontaneous contractile activity) in UBSM tissues isolated from guinea pigs and mice. In this review article, we present our data on these PAF effects together with the possible underlying mechanisms. We also discuss the potential pathophysiological roles of this phospholipid in UB diseases and disorders.

Management Strategies to Prevent Stroke in Patients with Atrial Fibrillation and Malignant Left Atrial Appendage

BackgroundPatients with atrial fibrillation (AF) and malignant left atrial appendage (LAA) may benefit from LAA closure (LAAC); however, evidence is limited. ObjectiveTo determine management strategies and clinical outcomes in patients with AF and malignant LAA. MethodsMalignant LAA was defined as ischemic stroke or LAA thrombus formation despite continuous oral anticoagulation (OAC) therapy (continuous for ≥3 weeks). We studied 80 patients with malignant LAA treated with LAAC. We compared these patients first against 44 patients with malignant LAA treated with OAC alone, and second against 114 patients without malignant LAA who were treated with LAAC for conventional indications. ResultsIn patients with malignant LAA (first-comparison), patients treated with LAAC had a higher 1-year cumulative incidence of ischemic stroke than patients treated with OAC alone (6.3% vs. 5.3%, log-rank P=0.09) whereas, the difference in stroke risk while receiving OAC was comparable (2.7% vs. 5.3%, log-rank P=0.84). Furthermore, all disabling stroke events among patients with malignant LAA treated with LAAC occurred only while not receiving OAC. In patients treated with LAAC (second-comparison), those with malignant LAA had a higher 1-year cumulative incidence of ischemic stroke (and ischemic stroke due to device-related thrombosis) than patients without malignant LAA (6.3% vs. 2.2%, log-rank P=0.009; 2.2% vs. 0%; log-rank P=0.04, respectively). However, these differences in stroke risk were no longer significant while receiving OAC (2.7% vs. 1.0%, log-rank P=0.11). ConclusionsBoth performing LAAC and continuation of OAC may be options to prevent ischemic stroke in patients with high thromboembolic risk and malignant LAA.

Propensity score-adjusted analysis on early tirofiban administration to prevent thromboembolic complications during stand-alone coil embolization of ruptured aneurysms

The glycoprotein IIb/IIIa antagonist tirofiban has been shown to prevent thromboembolic events during endovascular procedures, but the benefits and risks of its prophylactic early intraprocedural administration for stand-alone coil embolization of acutely ruptured aneurysms are still unclear. We conducted a retrospective single-center analysis of patients treated for aneurysmal subarachnoid hemorrhage with stand-alone coil embolization. Two study cohorts were compared according to the primary prophylactic antithrombotic medication during the procedure: patients receiving only intravenous heparin (HEP) versus patients receiving tirofiban in addition to heparin prior to final aneurysm obliteration (HEP + TF). Outcome endpoints were the incidence of angiographically visible thrombus formation or distal embolization, and the incidence of periprocedural intracranial hemorrhage (ICH). Of 204 cases, 159 were prophylactically treated with HEP and 45 with HEP + TF. Intraprocedural thromboembolic events were less frequent with HEP + TF before and after propensity score matching (PSM) (2.5% vs. 19.7%, p = 0.017). The incidence of ICH and symptomatic ICH did not differ between HEP + TF and HEP before and after PSM (20.5% vs. 30.7%, p = 0.29; and 5.1% vs. 4%, p = 0.88). Early intraprocedural tirofiban administration may be effective in preventing thromboembolic complications during stand-alone coil embolization of acutely ruptured aneurysms without increasing the risk of ICH.

Is acetylsalicylic acid use in cats contraindicated or limited indicated?

Acetylsalic acid, (Aspirin®) is a nonsteroidal anti-inflammatory drug (NSAID) widely used in human and veterinary medicine, especially for its analgesic and antithrombotic effects, mainly in the prevention of cardiovascular complications and in the treatment of various diseases. Aspirin® can not be metabolized in cats because they do not have the enzyme glucuronyl transferase. For this reason, it has a long half-life and a narrow dose range. High dose administration in cats may cause serious toxicity in the liver. Acetylsalicylic acid is known to cause gastric ulcers associated with decreased prostaglandin levels. For these reasons, it is considered toxic to cats. But it also has antipyretic, analgesic, anti-inflammatory and antithrombotic properties. It is indicated for use alone or in combination with other antithrombotic drugs in the treatment and prophylaxis of thrombus formation resulting from cardiovascular diseases. This review aims to examine the indicated and contraindicated areas of use of Aspirin®, which is widely considered toxic in cats.

GJA4 gene inhibition may represent a potential target for novel antithrombotic therapies

Abstract The GJA4 gene encodes a protein called connexin 37, a component of gap junctions in vascular endothelial cells, crucial in regulating endothelial function and influencing inflammation, platelet adhesion and thrombus formation. This gene deletion in mice diminished thrombus formation in vitro in human blood. In these circumstances, connexin inhibition with pharmacological agents may represent potential avenues for developing novel antithrombotic agents. Aim To investigate whether the GJA4 rs618675 T&amp;gt;C variant is a risk factor for progressing atherosclerosis and cardiovascular (CV) events in an asymptomatic free of apparent CAD from a Portuguese population. Methods A prospective study was performed with 1421 individuals without apparent CV disease (73.6% male, aged 52.2±8.3 years) followed during an extended period of 7.2±5.1 years). GJA4 rs618675 T&amp;gt;C variant was genotyped by TaqMan real-time PCR technique (Applied Biosystems). Conventional, anthropometric, biochemical and clinical risk factors were studied. Bivariate analysis and multivariate Cox regression adjusted for age, gender, traditional risk factors, biochemical markers, and the genotypes under study was performed to determine which variables were, significantly and independently, associated with CV events. Kaplan-Meier's estimate assessed the prognosis. Results Bivariate analysis showed that 50.6% of wild genotype (TT) carriers had CV events vs. 66.2% without events. Of the risk genotype (CC) carriers, 10.1% had CV events, and 3.4% did not. After the Kaplan-Meier analysis, the TT carriers had 90% CV event-free survival time and the CC risk carriers had only 64% of event-free survival. Finally, after adjustment, CC genotype remained in the equation with an HR of 3.1 (p=0.003) and CT heterozygous with HR of 1.6 (p=0.043), together with Hypertension (HR 3.0; p&amp;lt;0.0001), Smoking habits (HR 2.3; p=0.001) and Diabetes (HR 1.9; p=0.015). Conclusion: The CC risk genotype of the GJA4 rs618675 represented an independent risk factor for progressing atherosclerosis and CV events in a Portuguese Population. Thrombus formation often begins with the adhesion of platelets to the endothelium, and connexin 37 may influence this process. The inhibition of connexin 37 emerges as a promising candidate for future cardiovascular prevention as well as for the development of new antithrombotic drugs.

Sphingosine-1-phosphate reduces arterial thrombosis via enhanced endothelial thrombomodulin expression by S1PR1 signaling

Abstract Background Sphingosine 1-phosphate (S1P) is an important lipid mediator in the cardiovascular system. Numerous links between S1P and blood coagulation have been described. However, results regarding the role of S1P in coagulation are inconclusive. A physiological antithrombotic regulator expressed by endothelial cells (EC) is thrombomodulin (TM). To date, the impact of S1P on TM-expression is unknown. Methods We evaluated S1P effects on TM-expression and subsequent platelet adhesion and thrombus formation. For this, we conducted cell culture with human umbilical cord venous endothelial cells (HUVECs), flow cytometry and flow chamber experiments. Additionally, in vivo arterial thrombus formation in mice was analyzed. Results Sphingosine kinase-1 deficient mice (SphK1-/-) have about 70% less circulating plasma S1P and show a significant reduction in TM expression on the aorta as compared to their littermates (WT: 207.2 ± 45.8 pg/g Aorta vs. SphK1-/- 124.5 ± 40.2 pg/g Aorta, p&amp;lt;0.0001). In contrast, S1P incubation of 24 hours significantly increased TM-expression on HUVECs by about 30 percent. This effect was abolished by S1PR1-inhibition with W146. Treatment with S1P reduced platelet adhesion from whole blood to endothelial cells in the flow chamber experiments (Con: 100.00 ± 28.09% vs. S1P: 80.91 ± 22.85%, p&amp;lt;0.0001). This effect could be reversed both by S1PR1 inhibition and with a TM-neutralizing antibody. P-selectin-expression on platelets was decreased after incubation with TM suggesting (Ctrl: 62.79 ± 13.30% vs. TM: 43.47 ± 11.36%, p=0.0222). Finally, to assess the in vivo effects of our findings, arterial thrombus formation in mice was performed. TM inhibited in vivo thrombus formation. Occlusion of the carotid artery could not be detected during the 30 minutes recording. In contrast, SphK1-/- mice with low S1P levels showed decreased times to first occlusion. Treatment with TM in these animals was able to reverse this effect. Conclusion We can conclude that the main findings of our study were (i) S1P increased endothelial TM-expression, (ii) which subsequently leads to reduced platelet adhesion and (iii) inhibition of arterial thrombus formation in vivo.

CS585, a novel prostacyclin receptor agonist, demonstrates sustained efficacy in vivo in the prevention of thrombosis

Abstract Background Uncontrolled platelet activity resulting from cardiovascular disease can lead to occlusive thrombi, culminating in myocardial infarction or stroke. Despite major advances in anti-platelet therapeutics, many patients remain at risk. Although prostacyclin (IP) receptor agonists are currently used for the treatment of pulmonary arterial hypertension (PAH), activation of the IP receptor has been shown to decrease platelet reactivity. However, engaging the IP receptor as a therapeutic target was previously considered unviable due to the lack of a sustained effect of current IP agonists in the blood. The development of an IP agonist with sustained effects in the blood would represent a novel prevention strategy in targeting platelet hyperreactivity and thrombosis. Purpose Assess the stability profile of CS585, an IV and orally bioavailable IP agonist, compared to FDA-approved IP agonists iloprost and selexipag, with regards to sustained activity in vivo in the blood in limiting platelet activation and thrombosis. Methods Using ex vivo and in vivo mouse models, we assessed the timeframe of effect of CS585, iloprost and selexipag in blood. Blood was drawn from wild-type mice 24 hours following a single IV dose of CS585, iloprost or selexipag. Platelet adhesion and blood clotting were measured using perfusion flow chamber at arterial shear and total thrombus activation system (T-TAS), respectively. In vivo, platelets and fibrin were labelled 24 hours post IV or oral administration of CS585, iloprost or selexipag, and accumulation at the site of injury was measured using the cremaster arteriole injury thrombosis assay. Results Blood drawn from mice administered CS585 was observed to show a decrease in platelet adhesion and clot formation in the perfusion flow chamber and T-TAS assays. The effects of iloprost and selexipag are no longer observed at 24 hours post-administration. Administration of CS585 resulted in sustained inhibition of platelet accumulation and fibrin formation in the laser-induced cremaster arteriole thrombosis assay up to 18 hours post-administration. In mice administered iloprost, a decrease in thrombus formation was observed 10 minutes post-administration, but thrombus size returned to vehicle levels by 4 hours. Selexipag-dosed mice demonstrated inhibition of thrombus formation up to 4 hours, but effects were no longer observed at 18 hours. Conclusions CS585, a novel IP agonist, inhibits platelet activation and clot formation up to 24 hours post-administration. In both in vivo and ex vivo models, we demonstrate the sustained effects of CS585. In contrast, current FDA-approved IP agonists do not possess an effect profile sufficient to target the IP receptor in blood. By overcoming the sustainability challenge facing IP agonists, CS585 represents a novel approach to anti-platelet treatment of thrombotic diseases, which could include thrombosis, VTE, secondary prevention after MI and stroke, and PAH.

Direct Oral Anticoagulants versus Vitamin K Antagonists for the management of left ventricular thrombus after myocardial infarction: A meta-analysis

Abstract Background/Introduction Left ventricular (LV) thrombus formation is not an uncommon complication after acute myocardial infarction (AMI) in the modern era of early reperfusion. The optimal anticoagulation regimen in this clinical scenario remains poorly-defined. Purpose The present meta-analysis sought to investigate the efficacy and safety profile of direct oral anticoagulants (DOACs) compared with Vitamin K antagonists (VKAs) for the management of LV thrombus following AMI. Methods A systematic literature review was conducted in electronic databases to identify studies reporting efficacy and safety outcome data regarding the use of DOACs versus VKAs for patients with LV thrombus after MI. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated and random-effects meta-analyses were conducted to synthesize pooled ORs. Results Eight studies comprising a total of 605 patients were included (Table). DOACs were associated with an almost 2-fold higher likelihood for achieving thrombus resolution compared to VKAs (pooled OR 1.95 [1.25-3.04]; p =0.003, I2 =0 %), while they achieved a 70% lower risk for systemic embolism (pooled OR 0.30 [0.12-0.75]; p =0.01, I2 =0%). The use of DOACs was associated with a 54% lower risk for bleeding compared to VKAs (pooled OR 0.46 [0.26-0.84]; p =0.01, I2 =0 %). Overall, patients receiving DOACs had a 63% lower risk to reach the composite outcome of any bleeding, systemic embolism, cardiovascular hospitalization, or all-cause death, compared with patients using VKAs (pooled OR 0.37 [0.23-0.60]; p &amp;lt;0.0001, I2 =0%) (Figure). Conclusion DOACs appear to have a more favorable efficacy and safety profile compared to VKAs for the management of LV thrombus following AMI.Graphical abstractTable

Polyphenol-treatment without preceding glutaraldehyde fixation: a potential paradigm change for bioprosthetic heart valves

Abstract Background Glutaraldehyde (GA) is the common fixative agent for bioprosthetic heart valves (BHVs). However, its chemical instability can expose calcium binding sites and, at commercially used concentrations, GA does not ensure effective immunological tolerance, triggering an immune response correlated to degeneration. Recently, polyphenols (PPs) achieved an almost complete xenoantigens inactivation in GA-fixed BHVs ensuring chemical stability of the treated tissue while improving mechanical characteristics and adding anti-infective and anti-thrombotic properties [1-4]. Purpose A new PP-based treatment has been introduced as a potential GA substitute in BHV manufacturing. The unique chemical properties of PPs permit them to interact with the tissue through stable chemical bonds without depolymerization over time, achieving several improvements that promise to extend the long-term durability of BHVs (Fig.1). Methods The study compared the effects of two cross-linking methods on bovine pericardial tissue: (1) traditional fixation in GA, and (2) treatment with PPs without GA. The type of chemical interaction between PPs and tissue was evaluated through nuclear magnetic resonance. The xenoantigens inactivation was quantified in-vitro by ELISA test and in-vivo in a humanized mouse animal model. Biomechanical properties were assessed through uniaxial stress-strain tests and cross-link density through the shrinkage temperature test. The protective effect against bacterial adhesion was evaluated against a strain of S aureus, while the inhibition of thrombosis was evaluated in-vivo in a pig animal model and in-vitro in a blood-loop using bovine blood with radio-labeled platelets. Results PPs effectuated multiple chemical bonds with and within the pericardium including cross-links based on covalent and hydrogen bonds, stacking, and electrostatic interactions. The inactivation of over 90% of surface-xenoantigens of the treated tissue allowed for superior biocompatibility (compared to &amp;lt;50% by commercial GA concentrations). The increase in elongation exhibited by PP-treated tissue confirmed excellent biomechanical features (Fig.2) while a sufficient degree of cross-linking was demonstrated through an adequate shrinkage temperature. Furthermore, a significant degree of bacterial adhesion (86% inhibition evaluated with S. aureus) and thrombus formation (Fig.2, up to 90% inhibition) were observed. Conclusion There is a real clinical need for improved chemical stability, calcification resistance, and immunological tolerance of current BHVs (surgical and transcatheter). PP technology may substitute the use of GA extending their performance and durability, thereby opening trans-catheter heart valves to younger patients. Reducing the need for mechanical heart valves would also address the associated risks of lifelong anticoagulation therapy.Figure 1Figure 2

Septic Thrombophlebitis of the Umbilical Vein Complicating an Intrahepatic Umbilical Venous Catheter in a Premature Newborn

Septic thrombophlebitis of the umbilical vein (SVT) is a serious pathology in neonates, characterized by inflammation of the umbilical vein due to bacterial infection, with 90% of cases linked to the use of central venous catheters (CVCs). This inflammation can lead to thrombus formation as part of the immune system's response. Premature newborn, 33 weeks gestation, delivered vaginally, with history of gestational diabetes, twin pregnancy, macrosomia and premature rupture of membranes (57 hours), initially well adapted to extrauterine life, with a birth weight of 1575 g. The infant was admitted to neonatology for respiratory distress, and an intrahepatic umbilical catheter was inserted. On the 5th day of hospitalization, the infant developed a nosocomial Klebsiella pneumoniae infection, complicated by a fulminant hemorrhagic syndrome with hematemesis and melena. The clinical course was further complicated by multivisceral failure, requiring hepatic Doppler ultrasound, which revealed umbilical vein thrombosis. The newborn was treated with curative doses of Lovenox, while targeted antibiotic therapy was maintained for three weeks after negative blood cultures, resulting in significant clinical and biological improvement. Based on this case, we conclude that it is advisable to think about umbilical vein thrombosis and to perform an abdominal ultrasound in the presence of any digestive hemorrhage in a newborn or an intrahepatic or peripheral umbilical venous catheter, or in subjects at risk (hypotrophy, polycythemia, transfusion on the catheter) in order to screen for possible umbilical or portal vein thrombosis.

Abnormally high plasma concentrations of M-4, the active metabolite of edoxaban, at the onset of acute kidney injury in a patient receiving rifampin and clarithromycin: a case report

BackgroundEdoxaban, the only factor Xa inhibitor with active metabolites, is metabolized by carboxylesterase-1 to its main active metabolite, M-4, which is a substrate of organic anion transporting polypeptide 1B1 (OATP1B1) and is excreted in bile and urine. Because the area under the plasma concentration–time curve ratio of M-4 to parent compound is typically less than 10% in healthy subjects, M-4 is generally considered to exhibit negligible antithrombotic activity in patients treated with edoxaban. However, we identified a case in which drug interactions and kidney impairment led to a substantive increase in plasma M-4 concentrations.Case presentationThis case report involved a 68-year-old man with pancreatic cancer who was orally administered edoxaban tablets for prevention of thrombus formation in non-valvular atrial fibrillation, in addition to rifampin and clarithromycin (CAM) for treatment of mycobacterium avium complex lung disease. These medications were temporarily discontinued for a pancreaticoduodenectomy but were resumed 8 days post-surgery (POD8). On POD9, the patient developed acute kidney injury, and the trough concentrations of edoxaban and M-4 were 131.1 ng/mL and 115.8 ng/mL, respectively (M-4 ratio: 88.3%). On POD11, the M-4 trough concentration and M-4 ratio increased to 216.2 ng/mL and 186.2%, respectively. The plasma concentration of coproporphyrin-I, an endogenous biomarker of OATP1B1 activity, increased during this period.ConclusionsThis case suggests that in patients with impaired renal function taking edoxaban, co-administration of carboxylesterase-1 inducers such as rifampin and/or OATP1B1 inhibitors such as rifampin or clarithromycin may increase plasma concentrations of M-4 to clinically non-negligible levels.

Identification of left ventricular flow features in healthy and pathological conditions

Abstract Background In the presence of mitral valve diseases or following surgical interventions, the hemodynamics in the left ventricle (LV) are significantly altered [1]. These maladaptive intraventricular hemodynamic alterations can stimulate a cascade of events leading to progressive adverse LV remodeling and eventual heart failure [2]. Qualitative and quantitative evaluation of LV flow features may provide a potential for sensitive risk stratification of clinical cardiac function [3]. Purpose The purpose of this study is to identifying LV flow features using in vitro experiments under both normal and pathological conditions, including mitral regurgitation (MR), mitral valve replacement with bioprosthetic/mechanical valve, and transcatheter mitral valve edge-to-edge repair (TEER). Methods We utilized a biohybrid approach to construct the in vitro experimental platform, where the native mitral valve (including chordae tendineae and papillary muscles) and aortic valve from porcine were combined with a 3D-printed silicon LV (figure 1). To ensure comparability across different conditions, we maintained consistency by utilizing the same native valve and 3D-printed LV. For pathological conditions, we cut the chordae tendineae in A2 zone to induce the severe degenerative MR, and TEER was performed on this prolapsed valve by placing two clips in A2-P2 zone. Then, the anterior leaflet of valve was cut, and a bioprosthetic valve and mechanical valve were sutured to mitral annulus to simulate surgical valve replacement, respectively. Left ventricular flow fields were measured using four-dimensional particle image velocimetry (4D-PIV) technique, with vector interval of 0.9 mm in all the spatial directions and temporal resolution of 10 ms. Results Significant differences in mean flow field were observed among healthy and pathological conditions (figure 2). Firstly, the vortex orientation was clockwise in healthy, MR, bioprosthetic valve replacement, and TEER conditions, which could accompany the redirection of blood flows towards the aortic valve. However, the replacement with a mechanical valve resulted in an alteration in vortex orientation from clockwise to counterclockwise. Secondly, the position of the center of the vortex changed in pathological conditions, with the center of the vortex closest to the apex and the left ventricle outflow tract in the healthy condition. Thirdly, the maximum Reynolds shear stress (RSS), which may be responsible for thrombus formation, significantly increased after TEER procedure and bioprosthetic valve replacement. Conclusions This study demonstrates significant changes in LV hemodynamics across different conditions. The flow features, including vortex orientations, vortex positions and the RSS, may potentially become crucial considerations for the optimization of artificial valves and mitral valve repair devices.Figure 1 Figure 2