Arterial Thrombosis Research Articles

Clinical characteristics and thrombophilia associated gene variants in Egyptians with unprovoked venous thromboembolism: three centers experience.

Thrombophilias are characterized by excessive venous and arterial thrombosis at regular or unusual sites. It may result from inherited, acquired, or a combination. Hereditary thrombophilia (HT) is detected in 30-40% of patients with thromboembolism. Venous/arterial thrombosis is considered a multifactorial disorder, some patients may have more than one risk factor which may be transient or permanent. Assess the clinical characteristics of patients with unprovoked thromboembolic events and the role of inherited thrombophilia as a causative or additive risk factor. 210 consecutive adult patients with unprovoked thromboembolic events were reviewed in hematology units at three tertiary Egyptian centers between September 2022 and September 2023. The diagnosis of thromboembolic events was confirmed by clinical and radiological findings. Laboratory screening for thrombophilia-associated. Among our patients, 53(25.2%) patients presented with isolated DVT, followed by portal vein thrombosis, 32(15.2%) had a pulmonary embolism, and sagittal sinus thrombosis was developed in 23(10.9%) patients. Younger people who experience spontaneous thromboembolism run the chance of having hereditary thrombophilia; the more mutations discovered, the higher the risk of thrombosis; the lower leg and deep vein thrombosis were the most common sites. Lastly, MTHFR C677T was the most common polymorphism in Egyptians, detected in almost half of the cases.

Arterial anastomosis in LDLT: techniques and risks.

Reconstructing the hepatic artery in adult living donor liver transplantation is technically challenging, with complications leading to significant morbidity and mortality. Early arterial thrombosis can result in a mortality rate up to 50%, often necessitating re-transplantation. The most common techniques for arterial anastomosis include end-to-end reconstruction with interrupted or continuous sutures, either using magnifying loupes or a microscope. Although microscopes provide enhanced precision, they do not significantly reduce early thrombosis rates compared to loupes but increase surgical time. Overall, surgeons can achieve early thrombosis rates below 1% with experience and evolving techniques.

Failure to Rescue Pediatric Recipients of Living Donor Liver Transplantation: A Single-Center Study of Technical Complications in 500 Primary Grafts.

The concept of failure to rescue (FTR) has been used to evaluate the quality of care in several surgical specialties but has not been well-studied after living donor liver transplantation (LDLT) in children. This study retrospectively reviewed 500 pediatric LDLT performed at a single center between 1993 and 2022. The recipient outcomes were assessed by means of patient and graft survival rates, retransplantation rates, and arterial/portal/biliary complication rates. Graft and patient losses secondary to these complications were calculated regarding FTR for patients (FTRp) and grafts (FTRg). Overall 1- and 5-year patient survival rates were 94.5% and 92.1%, respectively, the corresponding figures for graft survival being 92.7% and 89.8%. One-year hepatic artery complication rate was 3.6% (n = 18 cases), the respective rates for portal vein complications and biliary complications being 5.7% (n = 57) and 15.6% (n = 101). One-year FTRp rates for hepatic artery thrombosis, portal vein thrombosis, anastomotic biliary stricture, and intrahepatic biliary stricture were 28.6%, 9.4%, 3.6%, and 0%, respectively. The corresponding FTRg rates being 21.4%, 6.3%, 0%, and 36.4%. Such novel analytical method may offer valuable insights for optimizing quality of care in pediatric LDLT.

Results of assessing cerebral vasospasm following subarachnoid hemorrhage using transcranial doppler ultrasound

SUMMARY Objective: Review the results of assessing cerebral vasospasm after subarachnoid hemorrhage using transcranial doppler ultrasound. Subjects and methods: A retrospective, cross-sectional descriptive study was performed on 39 patients with subarachnoid hemorrhage treated at the Neurology Center, Bach Mai Hospital from January 2020 to September 2023. Results: The mean age of the study group was 55.12 ± 14.33. The age group distribution with the highest incidence is 41-50 years old with a rate of 35.9%. The male/female ratio is 20/19. The most common symptoms were headache (97.4%), nausea and vomiting (92.3%), The least common symptoms were convulsions and hemiplegia in 5.1% of subjects. The most common clinical severity assessed by the Hunt and Hess scale is level 2 (59%), followed by level 3 (23.1%), level 4 (10.2%), and level 1 (5.1%). Evaluation of Fisher scale found that the most common fisher level is level 4 with a rate of 33.6%, followed by level 3 (28.2%), level 1 (25.6%), the least common is grade 2 with 2.6%. The results of the second transcranial Doppler ultrasound performed on the sixth to eighth day of the disease is the time with the highest rate of vasospasm, showing the most vasospasm cerebral artery is the middle cerebral artery: right middle cerebral artery. 35.9%, left middle cerebral artery 12.8%. Next is anterior cerebral artery spasm: right anterior cerebral artery 23.1%, left anterior cerebral artery 2.6%. Right posterior cerebral artery 10.3%, left posterior cerebral artery 5.1%. Compared to the gold standard for diagnosing vasospasm, which is 128-slices MSCT, transcranial Doppler ultrasound has a sensitivity of 0.91, a specificity of 0.88, a positive predictive value of 0.91, and a negative predictive value of 0.88. The appropriateness of transcranial Doppler ultrasound and 128-slices computed tomography scan in diagnosing cerebral vasospasm after subarachnoid hemorrhage is very high, Kappa coefficient = 0.791, statistically significant with p < 0.05. Conclusion: Clinical symptoms of the disease are very diverse and non-specific, the most common symptom being headache is 97.4%. The most common Hunt and Hess scale to assess clinical severity is 2, however the most common Fisher scale is 4. Middle cerebral artery thrombosis has the highest rate of spasm, followed by the anterior cerebral artery. Compared to the gold standard for diagnosing vasospasm, which is 128-slices MSCT, transcranial Doppler ultrasound has a sensitivity of 0.91, a specificity of 0.88, a positive predictive value of 0.91, and a negative predictive value of 0.88

Patient sex and use of tranexamic acid in liver transplantation.

Differences in medical treatment between women and men are common and involve out-of-hospital emergency care, the intensity of pain treatment, and the use of antifibrinolytic treatment in emergency trauma patients. If woman and man receive different antifibrinolytic treatment in highly-standardized major transplant surgery is unknown. We conducted a retrospective cohort study on patients who underwent liver transplantation at Heidelberg University Hospital, Heidelberg, Germany between 2004 and 2017. Logistic regression analyses were performed to determine if sex is associated with the administration of TXA during liver transplantation. Secondary endpoints included venous thrombotic complications, graft failure, mortality, myocardial infarction, hepatic artery thrombosis, and stroke within the first 30 days after liver transplant as well as length of hospital stay and length of intensive care unit stay. Out of 779 patients who underwent liver transplantation, 262 patients received TXA. Female sex was not associated with intraoperative administration of TXA [adjusted OR: 0.929 (95% CI 0.654; 1.320), p = 0.681]. The secondary endpoints graft failure (13.2% vs. 8.4%, women vs. men, p = 0.039), pulmonary embolism (3.4% vs. 0.9%, women vs. men, p = 0.012), stroke (1.7% vs. 0.4%, women vs. men, p = 0.049), and deep vein thrombosis (0.8% vs. 0%, women vs. men, p = 0.031) within 30 days after liver transplantation were more frequent in women. Mortality, myocardial infarction, and other secondary endpoints did not differ between groups. However, in women, the use of TXA was associated with a lower rate in thromboembolic complications. Our data indicate that different from other scenarios with massive bleeding complications the administration of TXA during liver transplantation is not associated with sex. However, sex is associated with the risk for complications, and in woman TXA might have a preventive effect on the rate of thromboembolic complications. Reasons underlying the observed sex bias rate remain uncertain.

Successful emergency renal auto-transplantation in a child with renovascular disease.

Renal artery occlusion is a rare but potentially catastrophic complication of paediatric endovascular renal artery intervention. Emergency auto-transplantation may be required to salvage the kidney; to date this has only been described in adults. We report our experience of performing emergency kidney auto-transplantation following acute renal artery thrombosis in a child undergoing redo renal artery angioplasty A 20-month-old boy presented with refractory hypertension and hypertensive cardiomyopathy secondary to multifocal fibromuscular dysplasia (FMD) with a single functioning kidney. Acute thrombosis of the renal artery during redo-endovascular balloon angioplasty necessitated emergency renal auto-transplantation. Subsequent acute kidney injury was reversible with benefit to renal function in the medium-term despite prolonged warm ischaemic time of two hours. We recommend that high-risk patients undergoing renal artery intervention do so at centres with on-site renal and vascular surgical backup.

Reversible Thrombocytopenia of Functional Platelets after Nose-Horned Viper Envenomation Is Induced by a Snaclec.

Profound and transient thrombocytopenia of functional platelets without bleeding was observed in patients envenomed by Vipera a. ammodytes (Vaa). This condition was rapidly reversed by administration of F(ab)2 fragments of immunoglobulin G targeting the whole venom, leaving platelets fully functional. To investigate the potential role of snake venom C-type lectin-like proteins (snaclecs) in this process, Vaa-snaclecs were isolated from the crude venom using different liquid chromatographies. The purity of the isolated proteins was confirmed by Edman sequencing and mass spectrometry. The antithrombotic effect was investigated by platelet agglutination and aggregation assays and blood coagulation tests. Using flow cytometry, the platelet activation and binding of Vaa-snaclecs to various platelet receptors was analyzed. Antithrombotic efficacy was tested in vivo using a mouse model of vascular injury. Two Vaa-snaclecs were purified from the venom. One of them, Vaa-snaclec-3/2, inhibited ristocetin-induced platelet agglutination. It is a covalent heterodimer of Vaa-snaclec-3 (α-subunit) and Vaa-snaclec-2 (β-subunit). Our results suggest that Vaa-snaclec-3/2 induces platelet agglutination and consequently thrombocytopenia by binding to the platelet receptor glycoprotein Ib. Essentially, no platelet activation was observed in this process. In vivo, Vaa-snaclec-3/2 was able to protect the mouse from ferric chloride-induced carotid artery thrombosis, revealing its applicative potential in interventional angiology and cardiology.

Ischemic events are infrequent in patients with ovarian hyperstimulation syndrome

BackgroundCase reports describe arterial thrombosis including ischemic stroke associated with severe ovarian hyperstimulation syndrome (OHSS), but the prevalence of major ischemic events during or shortly after OHSS is unknown. MethodsUsing publicly available administrative datasets in the United States between 2015 and 2020, we conducted two separate cross-sectional studies of patients with OHSS. We included all patients with OHSS. Our study outcome was any hospitalization for acute ischemic stroke, acute myocardial infarction, cerebral venous sinus thrombosis, pulmonary embolism, or acute deep venous thrombosis during the index hospitalization or within 90 days of OHSS diagnosis. Results and conclusionsWe found very few major ischemic events in patients with OHSS.

Comparison of the Efficacy and Safety of Low Molecular Weight Heparins and Fondaparinux in Patients With COVID-19: A Systematic Review and Meta-Analysis.

Individuals diagnosed with COVID-19 are at a higher risk of arterial and venous thrombosis, mostly pulmonary microvascular thrombosis, which may significantly impair treatment and result in morbidity. This is a systematic review and meta-analysis of research papers that aimto evaluate the risk of bleeding and thrombosis among patientstreated with low molecular weight heparin or fondaparinux (LMWH/F). Additionally, we measured the overall death events. This study was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. A search was conducted in the Clinicaltrials.gov, PubMed, Scopus, and Web of Science databases to identify observational cohort studies and randomized-controlled clinical trials (RCTs) that compared LMWH/F in proven COVID-19 patients. A total of 220 people from two studies were included. Patients who were treated with fondaparinux had a lower risk of developing venous thromboembolism (VTE) (odds ratio (OR) 0.39; 95% confidence interval (CI) (0.14, 1.096); p = 0.168); pulmonary embolism (OR 0.169, 95% CI (0.021, 1.356), p = 0.094); and deep vein thrombosis compared to patients who received LMWH therapy. The data show a lower mortality rate in the LMWH groups (OR 1.135, 95% CI (0.463, 2.785), p = 0.781) and a lower frequency of bleeding (OR 1.657, 95% CI (0.456, 5.908), p = 0.436). Both drugs have shown anti-thrombotic properties in COVID-19 patients. Fondaparinux was somewhat more effective in reducing thrombosis episodes. This research demonstrates the safe use of LMWH for VTE prophylaxis in hospitalized COVID-19 patients based on bleeding and mortality outcomes.

MASSIVE HEMORRHAGE DUE TO RUPTURE OF A RIGHT ILIAC ANEURYSM REVEALING BEHCET'S DISEASE: A CASE REPORT FROM THE FESTOC CENTER IN BAMAKO

INTRODUCTION: Behçet's disease is a chronic inflammatory disorder. It is clinically characterized by oral and genital aphthoses; skin lesions and systemic manifestations. Arterial aneurysms are defined as a loss of parallelism of the arterial walls, localized to an arterial segment, and corresponding to an increase of at least 50% of the normal arterial diameter. We report a case of Behcet's disease revealed by a ruptured aneurysm of the right primitive iliac artery. OBSERVATION: This was a 44-year-old patient with no known history, referred for management of a right inguinal mass that had progressively increased in volume and had been evolving for about 1 month. On admission, the physical examination revealed conjunctival pallor, a pulsatile right inguinal mass approximately 10 cm in diameter, and a suppurating sore on the scrotum. Doppler ultrasound of the lower limbs revealed an aneurysm of the right common iliac artery. The aneurysm ruptured during the short preparation period for surgery, resulting in cataclysmic hemorrhage. This prompted manual compression and the transfusion of several packed red blood cells. During transport to the OR, the patient experienced hemorrhagic shock and altered consciousness, prompting the administration of drugs (noradrenaline) and emergency orotracheal intubation. The aneurysm was controlled upstream and downstream by approaching the right primitive iliac artery, followed by dissection and clamping after general heparinization. The common femoral artery was then approached and checked. Surgical exploration revealed numerous clots which were evacuated, revealing a large neck extending over 7 cm. The procedure involved reconstruction of the common femoral artery with a patch saphenous graft and excision of the necrotic tissue. The post-operative course was marked by suppuration of the surgical wound, which progressed well with appropriate antibiotics and local care. CONCLUSION: Arterial involvement in Behçet's disease manifests as arterial thrombosis or, more frequently, aneurysm. This is due to inflammation of the media, intima and vasa vasorum. Their management can be envisaged in our context.

USP15-Mediated Deubiquitination of FKBP 5 and Activation of the αIIbβ3 Signaling Pathway Regulate Thrombosis in Mice.

Platelets have the hemostatic function, and their aberrant activation is associated with occlusive thrombus formation. Plasma exosomes are rich in platelets containing ubiquitin-specific peptidase 15 (USP15). Herein, we aim to explore the effect of USP15 on thrombosis, as well as expounding whether USP15 acts as an upstream target of FK506 binding protein 5 (FKBP5) to regulate occlusive thrombus formation. Washed human platelets were treated with thrombin for measurement of USP15 and FKBP5 expressions. USP15 loss/gain-of-function variant in HEK293 cells was performed by cell transfection, and the interaction between USP15 and FKBP5 was examined using immunoprecipitation and ubiquitination assays. Mice with USP15-knockout platelets (Plt USP15-/-) were modeled, and subjected to calculation of bleeding time, artery thrombosis imaging and clot retraction assay. FKBP5 expression and the inhibitor of nuclear factor kappa B kinase subunit epsilon (IKBKE)/phosphatidylinositol 3-kinase (PI3K)/Rap1 pathway in wild-type and Plt USP15-/- mice-derived platelets were detected using Western blot. The activation of αIIbβ3 in washed platelets was analyzed using flow cytometry. USP15 and FKBP5 expressions were upregulated in platelets after thrombin treatment. Following transfection of USP15 knockdown and USP15 overexpression plasmids into HEK293 cells, FKBP5 protein expression was downregulated by USP15 knockdown while being upregulated by USP15 overexpression. USP15 bound to FKBP5 and protected FKBP5 against ubiquitination. Knockdown of platelet USP15 prolonged bleeding time, inhibited arterial thrombosis and delayed clot retraction in mice. Knockdown of platelet USP15 also decreased protein expressions of FKBP5, IKBKE and Rap1, p-PI3K/PI3K ratio, and activation of αIIbβ3 in mice. USP15 knockdown in platelets affects thrombosis in mice by promoting the instability of FKBP5 to repress the activation of IKBKE/PI3K/Rap1 pathway-mediated αIIbβ3.

Comparison of Vascular Complications Between Living-donor and Deceased-donor Liver Transplantation – A Systematic Review and Meta-analysis

BackgroundVascular complications commonly cause graft loss and morbidity after liver transplantation (LT). Comparative data on the risk of vascular complications are limited. Hence, the present meta-analysis was conducted to analyze the difference in vascular complications between living-donor LT (LDLT) and deceased-donor LT (DDLT). MethodsA literature search of three databases was conducted for studies comparing the incidence of vascular complications with LDLT and DDLT. The event rates and odds ratios (OR) with 95% confidence intervals (CI) were calculated using a random-effects model. ResultsA total of 20 studies were included in the final analysis. There was no difference in the incidence of overall vascular complications (9.3%, 95% CI: 6.6 – 12.0 vs. 8.5%, 95% CI: 5.6 – 11.4) between LDLT and DDLT with OR 0.94 (95% CI: 0.73 – 1.21)(15 studies).There was a higher incidence of vascular complications with LDLT in older studies (published before 2013) but not in new studies. When comparing the individual complications, LDLT was associated with a higher incidence of hepatic artery thrombosis (HAT)(3.8%, 95% CI: 2.4 – 5.2 vs. 1.6%, 95% CI: 1.1 – 2.2)with OR 2.20 (95% CI: 1.53 – 3.17)(14 studies)and a significantly lower incidence of intraabdominal bleeding(4.8%, 95% CI: 3.3 – 6.2 vs. 7.9%, 95% CI: 5.0 – 10.7) with OR 0.64 (95% CI: 0.47 – 0.87)(11 studies). However, there was no difference in the incidence (2.1%, 95% CI: 0.5 – 3.8 vs. 1.0%, 95% CI: 0.1 – 1.9) of portal vein thrombosis between LDLT and DDLT with OR 1.85 (95% CI: 0.82 – 4.18) (6 studies). ConclusionDespite a comparable risk of vascular complications between LDLT and DDLT, LDLT was associated with a higher risk of HAT and a lower risk of intraprocedural bleeding. Further studies are required to analyze the effect of donor-recipient characteristics and surgical techniques on the risk of vascular complications.

Evaluating the Effectiveness of Enoxaparin in Treating Pediatric Arterial Thrombosis in Saudi Arabia.

Thrombosis is the abnormal formation of blood clots within blood vessels; it results from an imbalance between fibrinolytic, pro-coagulant, and anticoagulant systems. Pediatric arterial thrombosis, especially related to catheter usage, is an emerging issue with limited evidence. This study evaluates the efficacy of enoxaparin in treating arterial thrombosis in pediatric patients at a single center. A retrospective single-center study included children under 14 years old diagnosed with catheter-related arterial thrombosis (CAT) and treated with low-molecular-weight heparin (LMWH) at King Abdulaziz Medical City between 2016 and 2021. Patients without follow-up at our institution or those using other anticoagulants were excluded. Data collected included age, sex, weight, catheter type, location and degree of thrombosis, ultrasonographic results, treatment duration, hemoglobin and platelet levels, and missed refills. Radiologic confirmation of CAT was required for inclusion. This study included 111 children treated with enoxaparin for non-cerebral arterial thrombosis. The median age at diagnosis was 3 months, with 58% being male patients. Most cases (87%) involved cardiac catheterization, and all were confirmed using ultrasonography. Complete thrombus resolution was achieved in 90% of patients, partial resolution in 8.1%, and 1.8% had no resolution. The median duration of enoxaparin therapy was 20 days. Multivariate analysis indicated that higher age and lower body weight were associated with a higher risk of non-resolution. Indwelling catheters also posed a greater risk of non-resolution compared to cardiac catheters. Enoxaparin proved effective in treating catheter-related arterial thrombosis in children, with high resolution rates and few side effects. This study helps inform treatment strategies in pediatric thrombosis management and highlights the need for further research to refine treatment durations and address patient risk factors.

Arterial Thrombosis: Present and Future.

Arterial Thrombosis: Present and Future.

NADPH oxidase 1/4 dual inhibitor setanaxib suppresses platelet activation and thrombus formation

AimsThe production of reactive oxygen species (ROS) by NADPH oxidase (NOX) is able to induce platelet activation, making NOX a promising target for antiplatelet therapy. In this study, we examined the effects of setanaxib, a dual NOX1/4 inhibitor, on human platelet function and ROS-related signaling pathways. Materials and methodsIn collagen-stimulated human platelets, aggregometry, assessment of ROS and Ca2+, immunoblotting, ELISA, flow cytometry, platelet adhesion assay, and assessment of mouse arterial thrombosis were performed in this study. Key findingsSetanaxib inhibited both intracellular and extracellular ROS production in collagen-activated platelets. Additionally, setanaxib significantly inhibited collagen-induced platelet aggregation, P-selectin exposure from α-granule release, and ATP release from dense granules. Setanaxib blocked the specific tyrosine phosphorylation-mediated activation of Syk, LAT, Vav1, and Btk within collagen receptor signaling pathways, leading to reduced activation of PLCγ2, PKC, and Ca2+ mobilization. Setanaxib also inhibited collagen-induced activation of integrin αIIbβ3, which is linked to increased cGMP levels and VASP phosphorylation. Furthermore, setanaxib suppressed collagen-induced p38 MAPK activation, resulting in decreased phosphorylation of cytosolic PLA2 and reduced TXA2 generation. Setanaxib also inhibited ERK5 activation, affecting the exposure of procoagulant phosphatidylserine. Setanaxib reduced thrombus formation under shear conditions by preventing platelet adhesion to collagen. Finally, in vivo administration of setanaxib in animal models led to the inhibition of arterial thrombosis. SignificanceThis study is the first to show that setanaxib suppresses ROS generation, platelet activation, and collagen-induced thrombus formation, suggesting its potential use in treating thrombotic or cardiovascular diseases.

Berberine Targets PKM2 to Activate the t-PA-Induced Fibrinolytic System and Improves Thrombosis.

Arterial thrombosis, a condition in which thrombi form in arteries, can lead to various acute cardiovascular diseases and impact the quality of life and survival of patients. Berberine (BBR), a quaternary ammonium alkaloid, has been shown to treat these diseases. However, further exploration is needed to understand underlying mechanisms of BBR. Rats were administered BBR via intramuscular injection. Then, an FeCl3-coated filter paper was applied to a carotid artery to induce thrombosis. The size of the thrombus and the blood flow velocity were evaluated by carotid ultrasound. The shape of the thrombus was observed using staining and microscopy. The expression levels of mRNA and proteins were verified. Additionally, mass spectrometry and single-cell RNA sequencing analysis were conducted. The administration of BBR resulted in a significant reduction in the thrombus area and an extension of the thrombus-clogging time. Furthermore, BBR administration effectively reversed the decreasing tissue-plasminogen activator (t-PA) expression and alterations in fibrinolysis system of model group. Additionally, the expression of PKM2 was suppressed following BBR administration, and the overexpression of PKM2 inhibited t-PA expression. BBR ameliorates thrombosis by modulating expression of PKM2, subsequently impacting the expression of t-PA within fibrinolytic system. These preliminary findings suggest that BBR could be a potential preventive and therapeutic strategy for arterial thromboembolic diseases.

FREQUÊNCIA DA HOSPITALIZAÇÃO DOS CASOS DE EMBOLIA E TROMBOSE ARTERIAL EM MONTES CLAROS

Arterial thrombosis occurs when the formation of a blood clot completely blocks or impairs the flow of blood from an artery, which are the medium and large caliber vessels in our body responsible for transporting oxygen- and nutrient-rich blood to the tissues. This is a quantitative descriptive study whose data were collected in the Ministry of Health's online program TABNET-DATASUS, related to the municipality of Montes Claros, Minas Gerais. The selected variables were hospitalization by year of processing, age group, sex, color/race, and deaths during the period from 2017 to 2021. It is noted that with the analysis of the results obtained and the literature, that with advancing age, changes occur in normal aging, making individuals more prone to develop diseases, added to unhealthy habits and/or decompensated chronic diseases throughout life becomes even more predisposed.

Comparison of Different Animal Models in Hindlimb Functional Recovery after Acute Limb Ischemia-Reperfusion Injury.

Acute limb ischemia (ALI) is a sudden lack of blood flow to a limb, primarily caused by arterial embolism and thrombosis. Various experimental animal models, including non-invasive and invasive methods, have been developed and successfully used to induce limb ischemia-reperfusion injuries (L-IRI). However, there is no consensus on the methodologies used in animal models for L-IRI, particularly regarding the assessment of functional recovery. The present study aims to compare different approaches that induce L-IRI and determine the optimal animal model to study functional limb recovery. In this study, we applied a pneumatic cuff as a non-invasive method and ligated the aorta, iliac, or femoral artery as invasive methods to induce L-IRI. We have measured grip strength, motor function, creatine kinase level, inflammatory markers such as nuclear factor NF-κB, interleukin-6 (IL-6), hypoxia markers such as hypoxia-induced factor-1α (HIF-1α), and evaluated the muscle injury with hematoxylin and eosin (H&E) staining in Sprague Dawley rats after inducing L-IRI. The pneumatic pressure cuff method significantly decreased the muscle strength of the rats, causing the loss of ability to hold the grid and inducing significant limb function impairment, while artery ligations did not. We conclude from this study that the tourniquet cuff method could be ideal for studying functional recovery after L-IRI in the rat model.

A single-domain antibody targeting factor XII inhibits both thrombosis and inflammation

Factor XII (FXII) is the zymogen of the plasma protease FXIIa that activates the intrinsic coagulation pathway and the kallikrein kinin-system. The role of FXII in inflammation has been obscure. Here, we report a single-domain antibody (nanobody, Nb) fused to the Fc region of a human immunoglobulin (Nb-Fc) that recognizes FXII in a conformation-dependent manner and interferes with FXIIa formation. Nb-Fc treatment inhibited arterial thrombosis in male mice without affecting hemostasis. In a mouse model of extracorporeal membrane oxygenation (ECMO), FXII inhibition or knockout reduced thrombus deposition on oxygenator membranes and systemic microvascular thrombi. ECMO increased circulating levels of D-dimer, alkaline phosphatase, creatinine and TNF-α and triggered microvascular neutrophil adherence, platelet aggregation and their interaction, which were substantially attenuated by FXII blockade. Both Nb-Fc treatment and FXII knockout markedly ameliorated immune complex-induced local vasculitis and anti-neutrophil cytoplasmic antibody-induced systemic vasculitis, consistent with selectively suppressed neutrophil migration. In human blood microfluidic analysis, Nb-Fc treatment prevented collagen-induced fibrin deposition and neutrophil adhesion/activation. Thus, FXII is an important mediator of inflammatory responses in vasculitis and ECMO, and Nb-Fc provides a promising approach to alleviate thrombo-inflammatory disorders.

Study of platelet activation, hypercoagulable state, and pulmonary hypertension in patients with transfusion-dependent beta-thalassemia

Abstract: BACKGROUND: Thalassemic patients require lifelong blood transfusions, which can lead to complications such as pulmonary arterial hypertension. The pathogenesis involves hypercoagulability, in which researches on coagulation abnormalities in this regard are limited. OBJECTIVES: The aims of the study was to investigate the mechanism of hypercoagulability and pulmonary hypertension in transfusion-dependent thalassemic patients and compare it with healthy controls. PATIENTS MATERIALS AND METHODS: This case–control analysis enrolled 50 transfusion-dependent thalassemia patients and 50 healthy controls. Complete blood counts, liver function tests, coagulation markers (P-selectin, protein C, antithrombin III, and fibrinogen), serum ferritin, and transthoracic echocardiography were performed, and blood transfusion/chelation history and splenectomy status were recorded. RESULTS: Thalassemia patients revealed severe anemia, leukocytosis, thrombocytosis, significantly elevated serum ferritin (1957.50 ± 2455.05 g/L), elevated liver enzymes serum glutamic oxaloacetic transaminase (22.01 ± 9.89 U/L), serum glutamic pyruvic transaminase (22.70 ± 9.78 U/L) in comparison to controls, and mean serum P-selectin was significantly higher in thalassemic patients (100.48 ± 53.29 ng/mL). Mean serum antithrombin-III and protein C were significantly lower in thalassemic patients (89.27 ± 16.08 units/h, 86.04 ± 25.21 μg/mL) in comparison to controls. CONCLUSIONS: Transfusion-dependent thalassemia is characterized by severe anemia and splenomegaly, leading to complex hemodynamic changes with evidence of platelet activation, hypercoagulable state, liver injury, and increased atherosclerosis. It induces pulmonary artery thrombosis contributing to the development of pulmonary artery hypertension.