Search

Objective: To characterize surface-bound proteins and to measure the thickness of fibrin fibers bound to extracorporeal membrane oxygenation (ECMO) circuits used in children., Design: Single-center observational prospective study, April to November 2021., Setting: PICU, Royal Children's Hospital, Melbourne, Australia., Patients: Patients aged less than 18 years on venoarterial ECMO and without preexisting disorder., Interventions: None., Measurements and Main Results: ECMO circuits were collected from six patients. Circuit samples were collected from five different sites, and subsequently processed for proteomic and scanning electron microscopy (SEM) studies. The concentration of proteins bound to ECMO circuit samples was measured using a bicinchoninic acid protein assay, whereas characterization of the bound proteome was performed using data-independent acquisition mass spectrometry. The Reactome Over-representation Pathway Analyses tool was used to identify functional pathways related to bound proteins. For the SEM studies, ECMO circuit samples were prepared and imaged, and the thickness of bound fibrin fibers was measured using the Fiji ImageJ software, version 1.53c ( https://imagej.net/software/fiji/ ). Protein binding to ECMO circuit samples and fibrin networks showed significant intra-circuit and interpatient variation. The median (range) total protein concentration was 19.0 (0-76.9) μg/mL, and the median total number of proteins was 2011 (1435-2777). A total of 933 proteins were commonly bound to ECMO circuit samples from all patients and were functionally involved in 212 pathways, with signal transduction, cell cycle, and metabolism of proteins being the top three pathway categories. The median intra-circuit fibrin fiber thickness was 0.20 (0.15-0.24) μm, whereas the median interpatient fibrin fiber thickness was 0.18 (0.15-0.21) μm., Conclusions: In this report, we have characterized proteins and fiber fibrin thickness bound to ECMO circuits in six children. The techniques and approaches may be useful for investigating interactions between blood, coagulation, and the ECMO circuit and have the potential for circuit design., Competing Interests: Drs. McCafferty and Monagle’s institution received funding from the National Health and Medical Research Council (NHMRC) grant APP1129317. Dr. Attard’s institution received funding from the National Blood Authority, Bayer, and Janssen; he received funding from Anthos; he received support for article research from the NHMRC. Dr. MacLaren reported that he serves on the board of directors of the Extracorporeal Life Support Organization (unpaid). The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2024 by the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies.)

Background: Achieving first-pass recanalization (FPR) has become the primary procedural objective during thrombectomy in acute ischemic stroke patients as it correlates with the best clinical outcome. Understanding factors contributing to FPR failures is essential to enhance FPR success rates. As the central target of thrombectomy, the thrombus itself may be a significant factor influencing FPR., Objectives: This study aimed to investigate the association between thrombus composition and FPR success rates., Methods: In total, thrombi from 267 ischemic stroke patients were collected in the AZ Groeninge Hospital (Kortrijk, Belgium). Thrombus composition was determined via detailed histologic analysis of red blood cells (RBCs), fibrin, von Willebrand factor, platelets, leukocytes, citrullinated histone 3 (marker for neutrophil extracellular traps), and intracellular and extracellular DNA. FPR was defined as obtaining a modified thrombolysis in cerebral infarction (mTICI) score of 2c/3 after the first pass., Results: An mTICI score of 2c/3 was obtained in 180 patients, which was achieved via a successful FPR procedure in 126 cases or after multiple passes in 54 cases. Interestingly, thrombi from FPR cases had a different composition from thrombi that needed multiple passes to obtain an mTICI score of 2c/3. FPR thrombi contained significantly more RBCs (P = .0264), less fibrin (P = .0196), and less extracellular DNA (P = .0457)., Conclusion: Our results indicate that thrombi characterized by lower RBC content, higher fibrin levels, and increased extracellular DNA are less likely to result in an FPR. These results are important to guide future research aiming at improving procedures or technologies to obtain FPR rates in RBC-poor thrombi., Competing Interests: Declaration of competing interests P.V. received speaker fees from Boehringer-Ingelheim, BMS, Pfizer, Daiichi-Sankyo, and Medtronic. T.A. holds equity for Cereflo Ltd and is a consultant for Anaconda, Cerenovus/Neuravi, Optimize Neurovascular, and Rapid Medical. O.F. is a consultant for iVascular. All other authors have no conflicting interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Breast implant-associated (BIA) lymphoma is a rare malignancy, typically originating from T-cells; however, few cases of diffuse large B-cell lymphoma (LBCL) have been recently described. These cases share major features: Epstein-Barr virus positivity and a favorable prognosis with surgical intervention alone, hinting at a potential link to fibrin-associated LBCL (FA-LBCL). This study presents the first case of BIA-FA-LBCL in Italy and one of the few assessed from a molecular standpoint so far. We identified two pathogenic mutations in DNMT3A and a variant of uncertain significance (VUS) in JAK2. These findings suggest that dysfunctional epigenetic mechanisms and constitutive activation of the JAK-STAT pathway may underpin BIA-FA-LBCL lymphomagenesis. Finally, we summarized all the previously reported cases in alignment with the updated WHO-HAEM5 classification, shedding further light on the nature of this new entity. This report highlights the rarity of BIA-FA-LBCL and underscores the importance of comprehensive capsule sampling and reporting to national databases for accurate characterization and management of these lymphomas. The study supports the classification of BIA-FA-LBCL within the spectrum of FA-LBCL, emphasizing the need for further research to elucidate its molecular underpinnings and improve clinical outcomes., (Copyright © 2024 Società Italiana di Anatomia Patologica e Citopatologia Diagnostica, Divisione Italiana della International Academy of Pathology.)

Background: Mechanical thrombectomy has emerged as the primary endovascular treatment for acute ischemic stroke. Numerous studies have investigated the relationship between thrombus composition and factors such as pharmacological thrombolysis, stroke etiology, mechanical thrombectomy, and radiological imaging. However, limited research has explored the association between thrombus composition and clinical outcomes., Methods: This retrospective analysis examined the histopathological examination of thrombi retrieved from 50 patients with acute ischemic stroke between May 2020 and May 2023. The composition of the retrieved thrombi was assessed using HE staining to quantify the proportions of red blood cells, white blood cells, platelets, and fibrin. Based on the predominant composition of the thrombus, the patients were divided into two groups: erythrocyte-rich and fibrin-rich. Demographics, clinical characteristics, and clinical outcomes assessed by the National Institutes of Health Stroke Scale (NIHSS) score and modified Rankin Scale (mRS) scores were collected retrospectively., Result: Of the 50 patients, 23 were classified in the erythrocyte-rich group, and 27 were classified in the fibrin-rich group. There were no significant differences between the two groups in terms of age, sex, stroke subtype, history of hypertension and diabetes, thrombus location, NIHSS scores, mRS scores on admission, the time interval from symptom onset to hospitalization and reperfusion, or the rate of successful reperfusion. However, erythrocyte-rich thrombi were associated with a shorter time interval from puncture to reperfusion. No significant differences were found in the red blood cell fraction and fibrin/platelet fraction between large artery atherosclerosis and cardioembolism. At the 90-day follow-up, patients with erythrocyte-rich thrombi exhibited lower NIHSS scores and more favorable functional outcomes (mRS scores of 0-2) compared to those with fibrin-rich thrombi., Conclusion: Erythrocyte-rich thrombi were linked to shorter time intervals from puncture to reperfusion and favorable clinical outcomes in patients with acute ischemic stroke. The composition of the thrombus may influence the thrombectomy strategy for endovascular therapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Mechanical thrombectomy (MT) has become the gold standard care for treating acute ischemic stroke (AIS) due to large vessel occlusion. Emerging evidence suggests that understanding the composition of clots prior to intervention could be useful for the selection of neuroendovascular techniques, potentially improving the efficacy of treatments. However, current imaging modalities lack the ability to distinguish clot composition accurately and reliably. Since water content can influence signal intensity on CT and MRI scans, its assessment may provide indirect clues about clot composition. This study aimed to elucidate the correlation between water content and clot composition using human clots retrieved from stroke patients and experimentally generated ovine clots., Materials and Methods: This study involved an analysis of ten clots retrieved from patients with AIS undergoing MT. Additionally, we created ten red blood cells (RBC)-rich and ten fibrin-rich ovine blood clots, which were placed in a human intracranial vascular model under realistic flow conditions. The water content and compositions of these clots were evaluated, and linear regression analyses were performed to determine the relationship between clot composition and water content., Results: The regression analysis in human stroke clots revealed a significant negative association between RBC concentration and water content. We also observed a positive correlation between water content and both fibrin and platelets in ovine blood clots. Conclusion., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Sakuta et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Ultrasensitive, selective, and non-invasive detection of fibrin in human serum is critical for disease diagnosis. So far, the development of high-performance and ultrasensitive biosensors maintains core challenges for biosensing. Herein, we designed a novel ribbon nanoprobe for ultrasensitive detection of fibrin. The probe contains gold nanoparticles (AuNPs) that can not only link with homing peptide Cys-Arg-Glu-Lys-Ala (CREKA) to recognize fibrin but also carry long DNA belts to form G-quadruplex-based DNAzyme, catalyzing the chemiluminescence of luminol-hydrogen peroxide (H 2 O 2 ) reaction. Combined with the second amplification procedure of rolling circle amplification (RCA), the assay exhibits excellent sensitivity with a detection limit of 0.04 fmol L -1 fibrin based on the 3-sigma. Furthermore, the biosensor shows high specificity on fibrin in samples because the structure of antibody-fibrin-homing peptide was employed to double recognize fibrin. Altogether, the simple and inexpensive approach may present a great potential for reliable detection of biomarkers., (© 2024 John Wiley & Sons Ltd.)

Background: Nowadays, there is no method to quantitatively characterize the material composition of acute ischemic stroke thrombi prior to intervention, but dual-energy CT (DE-CT) offers imaging-based multimaterial decomposition. We retrospectively investigated the material composition of thrombi ex vivo using DE-CT with histological analysis as a reference., Methods: Clots of 70 patients with acute ischemic stroke were extracted by mechanical thrombectomy and scanned ex vivo in formalin-filled tubes with DE-CT. Multimaterial decomposition in the three components, i.e., red blood cells (RBC), white blood cells (WBC), and fibrin/platelets (F/P), was performed and compared to histology (hematoxylin/eosin staining) as reference. Attenuation and effective Z values were assessed, and histological composition was compared to stroke etiology according to the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria., Results: Histological and imaging analysis showed the following correlation coefficients for RBC (r = 0.527, p < 0.001), WBC (r = 0.305, p = 0.020), and F/P (r = 0.525, p < 0.001). RBC-rich thrombi presented higher clot attenuation in Hounsfield units than F/P-rich thrombi (51 HU versus 42 HU, p < 0.01). In histological analysis, cardioembolic clots showed less RBC (40% versus 56%, p = 0.053) and more F/P (53% versus 36%, p = 0.024), similar to cryptogenic clots containing less RBC (34% versus 56%, p = 0.006) and more F/P (58% versus 36%, p = 0.003) than non-cardioembolic strokes. No difference was assessed for the mean WBC portions in all TOAST groups., Conclusions: DE-CT has the potential to quantitatively characterize the material composition of ischemic stroke thrombi., Relevance Statement: Using DE-CT, the composition of ischemic stroke thrombi can be determined. Knowledge of histological composition prior to intervention offers the opportunity to define personalized treatment strategies for each patient to accomplish faster recanalization and better clinical outcomes., Key Points: • Acute ischemic stroke clots present different recanalization success according to histological composition. • Currently, no method can determine clot composition prior to intervention. • DE-CT allows quantitative material decomposition of thrombi ex vivo in red blood cells, white blood cells, and fibrin/platelets. • Histological clot composition differs between stroke etiology. • Insights into the histological composition in situ offer personalized treatment strategies., (© 2024. The Author(s).)

Here, we present a case of severe glomerular fibrin thrombosis in a dog with lymphoma. A 3-year-old neutered male Chihuahua presented with acute kidney injury, hypoalbuminemia, and transudate ascites. The dog showed symmetric enlargement of the spleen, which was diagnosed as B-cell lymphoma based on cytology and polymerase chain reaction tests. The dog died after intensive care, and the kidneys were removed for histopathological examination. Light microscopy, immunofluorescence, and electron microscopy analyses were performed for renal pathology; however, the findings did not support the evidence of protein-losing nephropathy. Instead, the endocapillary accumulation of fibrin thrombi was prominent in most glomeruli. A diagnosis of severe glomerular fibrin thrombosis was established, and hypoalbuminemia was considered the underlying cause of kidney damage.

Biochemical and biophysical properties instruct cardiac tissue morphogenesis. Here, we are reporting on a blend of cardiac decellularized extracellular matrix (dECM) from porcine ventricular tissue and fibrinogen that is suitable for investigations employing an in vitro 3D cardiac cell culture model. Rapid and specific coagulation with thrombin facilitates the gentle inclusion of cells while avoiding sedimentation during formation of the dECM-fibrin composite. Our investigations revealed enhanced cardiogenic differentiation in the H9c2 myoblast cells when using the system in a co-culture with Nor-10 fibroblasts. Further enhancement of differentiation efficiency was achieved by 3D embedding of rat neonatal cardiomyocytes in the 3D system. Calcium imaging and analysis of beating motion both indicate that the dECM-fibrin composite significantly enhances recovery, frequency, synchrony, and the maintenance of spontaneous beating, as compared to various controls including Matrigel, pure fibrin and collagen I as well as a fibrin-collagen I blend.

Purpose: To establish a nomogram incorporating pretreatment imaging parameters and clinical characteristics for predicting the thrombus composition of acute ischemic stroke (AIS) with large vessel occlusion (LVO)., Methods: We retrospectively enrolled patients with occlusion of the Middle Cerebral Artery (MCA) who underwent Mechanical Thrombectomy (MT). Retrieved thrombi were stained with Hematoxylin and Eosin (H&E) and Martius Scarlet Blue (MSB). Thrombi are assigned to the Fibrin-rich or RBC-rich group based on the relative fractions of Red Blood Cells (RBC), fibrin, and platelet. The independent risk factors for Fibrin-rich clots were determined via univariate and multivariate logistic regression analysis and were then integrated to establish a nomogram., Results: In total, 98 patients were included in this study. Patients with fibrin-rich clots had worse functional outcome [modified Rankin scale (mRS) 0-2, 34.7% vs 63.2%, p = 0.005], longer procedure time (76.8 min vs 50.8 min, p = 0.001), and increased maneuvers of MT (1.84 vs 1.46, p = 0.703) than those with RBC-rich clots. The independent risk factors for Fibrin-rich clots were lower perviousness measured by Non-Contrast Computer Tomography (NCCT) and CT Angiography (CTA), lower thrombus relative attenuation on NCCT, elevated Platelet-WBC ratio (PWR) of admission peripheral blood, and previous antithrombotic medication. The nomogram showed good discrimination with an area under the Receiver Operating Characteristic (ROC) curve (AUC) of 0.852 (95% CI: 0.778-0.926). The calibration curve and decision curve analysis also displayed satisfactory accuracy and clinical utility., Conclusion: This study has developed and internally validated an easy-to-use nomogram which can help predict clot composition and optimize therapeutic strategies for thrombectomy., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Compositional and structural features of retrieved clots by thrombectomy can provide insight into improving the endovascular treatment of ischemic stroke. Currently, histological analysis is limited to quantification of compositions and qualitative description of the clot structure. We hypothesized that heterogeneous clots would be prone to poorer recanalization rates and performed a quantitative analysis to test this hypothesis., Methods: We collected and did histology on clots retrieved by mechanical thrombectomy from 157 stroke cases (107 achieved first-pass effect (FPE) and 50 did not). Using an in-house algorithm, the scanned images were divided into grids (with sizes of 0.2, 0.3, 0.4, 0.5, and 0.6 mm) and the extent of non-uniformity of RBC distribution was computed using the proposed spatial heterogeneity index (SHI). Finally, we validated the clinical significance of clot heterogeneity using the Mann-Whitney test and an artificial neural network (ANN) model., Results: For cases with FPE, SHI values were smaller (0.033 vs 0.039 for grid size of 0.4 mm, P=0.028) compared with those without. In comparison, the clot composition was not statistically different between those two groups. From the ANN model, clot heterogeneity was the most important factor, followed by fibrin content, thrombectomy techniques, red blood cell content, clot area, platelet content, etiology, and admission of intravenous tissue plasminogen activator (IV-tPA). No statistical difference of clot heterogeneity was found for different etiologies, thrombectomy techniques, and IV-tPA administration., Conclusions: Clot heterogeneity can affect the clot response to thrombectomy devices and is associated with lower FPE. SHI can be a useful metric to quantify clot heterogeneity., Competing Interests: Competing interests: MJG is on the editorial board of the Journal of NeuroInterventional Surgery., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: Platelet-rich fibrin (PRF) has been proposed as promising biomaterials with the advantages of host accumulation of platelets and leukocytes with entrapment of growth factors and fibrin scaffold. However, limitations including fast resorption rate (~ 2 weeks) restricts its clinical application. Recent studies have demonstrated heating treatment can prolong PRF degradation. Current published articles used the method of 75 °C for 10 min to obtain longer degradation, while few studies investigated the most suitable temperature for heating horizontal PRF. Our present study was to discover and confirm the optimum temperature for heat treatment before obtaining H-PRF gels by investigating their structure, mechanical properties, and bioactivity of the H-PRF gels after heating treatment., Methods: In the present study, 2-mL upper layer of horizontal PRF was collected and heated at 45 °C, 60 °C, 75 °C, and 90 °C to heat 2-mL upper layer of horizontal PRF for 10 min before mixing with the 2-mL lower layer horizontal PRF. The weight, solidification time and the degradation properties were subsequently recorded. Scanning electron microscopy (SEM) and rheologic tests were carried out to investigate the microstructure and rheologic properties of each H-PRF gel. The biological activity of each H-PRF gel was also evaluated using live/dead staining., Results: H-PRF gel prepared at 75 °C for 10 min had the fast solidification period (over a tenfold increase than control) as well as the best resistance to degradation. The number of living cells in H-PRF gel is greater than 90%. SEM showed that H-PRF gel becomes denser as the heating temperature increases, and rheologic tests also revealed that the heat treatment improved the mechanical properties of H-PRF gels when compared to non-heated control group. Future clinical studies are needed to further support the clinical application of H-PRF gels in tissue regeneration procedures., Conclusions: Our results demonstrated that the H-PRF gel obtained at 75 °C for 10 min could produce a uniform, moldable gel with a short time for solidification time, great rheologic behavior and, high percent of live cells in PRF gel. A promising use of the commonly utilized PRF gel was achieved facilitating tissue regeneration and preventing degradation., (© 2022. The Author(s).)

Objectives: Intra-device thrombosis remains one of the most common complications during extracorporeal membrane oxygenation (ECMO). Despite anticoagulation, approximately 35% of patients develop thrombi in the membrane oxygenator, pump heads, or tubing. The aim of this study was to describe the molecular and cellular features of ECMO thrombi and to study the main drivers of thrombus formation at different sites in the ECMO circuits., Approach and Results: Thrombi (n = 85) were collected immediately after veno-arterial-(VA)-ECMO circuit removal from 25 patients: 23 thrombi from the pump, 25 from the oxygenator, and 37 from the tubing. Quantitative histological analysis was performed for the amount of red blood cells (RBCs), platelets, fibrin, von Willebrand factor (VWF), leukocytes, and citrullinated histone H3 (H3Cit). ECMO thrombi consist of a heterogenous composition with fibrin and VWF being the major thrombus components. A clustering analysis of the four major histological parameters identified two typical thrombus types: RBC-rich and RBC-poor/fibrin-rich thrombi with no significant differences in VWF and platelet content. Thrombus composition was not associated with the thrombus location, except for higher amounts of H3Cit that were found in pump and oxygenator thrombi compared to tubing samples. We observed higher blood leukocyte count and lactate dehydrogenase levels in patients with fibrin-rich thrombi., Conclusion: We found that thrombus composition is heterogenous, independent of their location, consisting of two types: RBC-rich and a fibrin-rich types. We also found that NETs play a minor role. These findings are important to improve current anticoagulation strategies in ECMO., (© 2022 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals LLC on behalf of International Society on Thrombosis and Haemostasis.)

We observed an increased frequency of massive perivillous fibrin deposition (MPFD) during the second coronavirus disease 2019 (COVID-19) pandemic wave dominated by the Alpha variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). MPFD associated with 100% reverse transcription polymerase chain reaction (RT-PCR) positivity for SARS-CoV-2 and detection by immunohistochemistry. The Alpha variant was identified in all placentas with MPFD that could be sequenced., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: The procoagulant state in cancer increases the thrombotic risk, and underlying cancer could affect treatment strategies and outcomes in patients with ischemic stroke. However, the histopathological characteristics of retrieved thrombi in patients with cancer have not been well studied. This study aimed to assess the histopathological difference between thrombi in patients with and without cancer., Methods: We studied consecutive patients with acute major cerebral artery occlusion who were treated with endovascular therapy between October 2010 and December 2016 in our single-center registry. The retrieved thrombi were histopathologically investigated with hematoxylin and eosin and Masson's trichrome staining. The organization and proportions of erythrocyte and fibrin/platelet components were studied using a lattice composed of 10×10 squares., Results: Of the 180 patients studied, 17 (8 women, age 76.5±11.5 years) had cancer and 163 (69 women, age 74.1±11.2 years) did not. Those with cancer had a higher proportion of fibrin/platelets (56.6±27.4% vs 40.1±23.9%, p=0.008), a smaller proportion of erythrocytes (42.1±28.3% vs 57.5±25.1%, p=0.019), and higher serum D-dimer levels (5.9±8.2 vs 2.4±4.3 mg/dL, p=0.005) compared with the non-cancer cases. Receiver operating characteristic curve analysis showed the cut-off ratio of fibrin/platelet components related to cancer was 55.7% with a sensitivity of 74.8%, specificity 58.8% and area under the curve (AUC) value of 0.67 (95% CI 0.53 to 0.81), and the cut-off ratio of erythrocyte components was 44.7% with a sensitivity of 71.2%, specificity 58.9% and AUC value of 0.66 (95% CI 0.51 to 0.80)., Conclusions: Thromboemboli of major cerebral arteries in patients with cancer were mainly composed of fibrin/platelet-rich components., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Aims: Large amounts of clot-bound lipoproteins were reported in proteomic analysis of plasma clot but their impact on fibrin clot properties is unknown. We investigated a contribution of lipid profile and apolipoproteins (apo) to the prothrombotic plasma fibrin clot phenotype in patients with aortic stenosis (AS)., Methods: In 138 patients with isolated severe AS, we determined serum apoA-I, A-II, B, C-II, C-III, E, oxidized low-density lipoprotein (OxLDL) and lipoprotein(a) concentrations. Plasma fibrin clot permeability (Ks), maximal absorbance (MaxAbs CLT2018 and MaxAbs Lys50 ), and fibrinolytic capacity were studied using 3 plasma-based lysis assays (CLT2018, CLT, and Lys50), and compared with well-matched patients without AS (control group)., Results: After adjustment for confounding factors, including statin use, only low-density lipoprotein cholesterol (LDL-C) and apoB levels were inversely associated with Ks. Triglycerides, apoC-II, and C-III were associated with MaxAbs CLT2018 and MaxAbs Lys50 , explaining 56-64% of their variability. CLT2018 and CLT showed associations with total cholesterol, LDL-C, triglycerides, and OxLDL as well as with apoB, C-II, C-III, and E. ApoA-I, C-II, and C-III but not serum lipids were associated with Lys50. Only CLT2018 was associated with lipoprotein(a). ApoC-III, B, A-I, and E along with estimated glomerular filtration rate and OxLDL predicted hypofibrinolysis in multiple regression analysis. AS patients had higher lipoprotein(a) (+34.9%) and apoA-I (+25.9%) levels and less compact fibrin clots (-13.3% lower MaxAbs CLT2018 , -53.2% lower MaxAbs Lys50 , and +28.3% higher Ks) displaying higher susceptibility to lysis (-17.9% lower Lys50) in comparison with control group., Conclusions: Apolipoproteins and OxLDL contribute to prothrombotic fibrin clot phenotype in severe AS. Moreover, apolipoproteins better than serum lipids predicted hypofibrinolysis, which provides additional argument for a role of elevated lipoproteins in the prothrombotic state., (Copyright © 2022 Elsevier B.V. All rights reserved.)

We describe the internal structure, spatial organization and dynamic formation of coronary artery thrombi from ST-segment elevation myocardial infarction patients. Scanning electron microscopy (SEM) revealed significant differences among four groups of patients (<2 hours; 2-6 hours; 6-12 hours, and >12 hours) related to the time of ischemia. Coronary artery thrombi from patients presenting less than 2 hours after the infarction were almost entirely composed of platelets, with small amounts of fibrin and red blood cells. In contrast, thrombi from late presenters (>12 hours) consisted of mainly platelets at the distal end, where clotting was initiated, with almost no platelets at the proximal end, while the red blood cell content went from low at the initiating end to more than 90% at the proximal end. Furthermore, fibrin was present mainly on the outside of the thrombi and older thrombi contained thicker fibers. The red blood cells in late thrombi were compressed to a close-packed, tessellated array of polyhedral structures, called polyhedrocytes. Moreover, there was redistribution from the originally homogeneous composition to fibrin and platelets to the outside, with polyhedrocytes on the interior. The presence of polyhedrocytes and the redistribution of components are signs of in vivo clot contraction (or retraction). These results suggest why later thrombi are resistant to fibrinolytic agents and other treatment modalities, since the close-packed polyhedrocytes form a nearly impermeable seal. Furthermore, it is of particular clinical significance that these findings suggest specific disparate therapies that will be most effective at different stages of thrombus development., Competing Interests: None declared., (Thieme. All rights reserved.)

This retrospective study performed to investigate direct immunofluorescence (DIF) findings in oral and cutaneous lichen planus (LP), and to identify any differences between them. There were 147 patients with a definite diagnosis of LP by clinical and histological criteria, with 87 (59.2%) oral and 60 (40.8%) cutaneous specimens. Of these, 125 (85%) had positive DIF findings, with positive yields being significantly lower in oral (79.3%) than in cutaneous (93.3%) LP. Deposition of immunoreactants at the dermoepidermal junction (DEJ) was significantly greater in oral than in cutaneous LP, and fibrin deposition with shaggy pattern at the DEJ was also significantly greater in oral than in cutaneous LP. Deposition of immunoreactants at colloid bodies (CBs) with or without DEJ was significantly greater in cutaneous than in oral LP. IgM deposition at CBs was commonly detected in both groups. We propose that fibrin deposition with shaggy pattern at the DEJ is the best diagnostic indicator of oral LP., (© 2021 British Association of Dermatologists.)

Case-control and observational studies have provided a plausible mechanistic link between clot structure and thrombosis. We aimed to identify lifestyle, demographic, biochemical, and genetic factors that influence changes in total fibrinogen concentration and clot properties over a 10-year period in 2,010 black South Africans. Clot properties were assessed with turbidimetry and included lag time, slope, maximum absorbance, and clot lysis time. Linear mixed models with restricted maximum likelihood were used to determine whether (1) outcome variables changed over the 10-year period; (2) demographic and lifestyle variables, biochemical variables, and fibrinogen single-nucleotide polymorphisms influenced the change in outcome variables over the 10-year period; and (3) there was an interaction between the exposures and time in predicting the outcomes. A procoagulant risk score was furthermore created, and multinomial logistic regression was used to determine the exposures that were associated with the different risk score categories. In this population setting, female gender, obesity, poor glycemic control, increased low-density lipoprotein cholesterol, and decreased high-density lipoprotein cholesterol contributed to the enhanced progression to prothrombotic clot properties with increasing age. Alcohol consumption on the other hand, offered a protective effect. The above evidence suggest that the appropriate lifestyle changes can improve fibrin clot properties on a population level, decreasing cardiovascular disease risk and thus alleviate the strain on the medical health care system., Competing Interests: None declared., (Thieme. All rights reserved.)

Introduction: Recent evidence supports the - rare - occurrence of vertical transplacental SARS-CoV-2 transmission. We previously determined that placental expression of angiotensin-converting enzyme 2 (ACE2), the SARS-CoV-2 receptor, and associated viral cell entry regulators is upregulated by hypoxia. In the present study, we utilized a clinically relevant model of SARS-CoV-2-associated chronic histiocytic intervillositis/massive perivillous fibrin deposition (CHIV/MPFVD) to test the hypothesis that placental hypoxia may facilitate placental SARS-CoV-2 infection., Methods: We performed a comparative immunohistochemical and/or RNAscope in-situ hybridization analysis of carbonic anhydrase IX (CAIX, hypoxia marker), ACE2 and SARS-CoV-2 expression in free-floating versus fibrin-encased chorionic villi in a 20-weeks' gestation placenta with SARS-CoV-2-associated CHIV/MPVFD., Results: The levels of CAIX and ACE2 immunoreactivity were significantly higher in trophoblastic cells of fibrin-encased villi than in those of free-floating villi, consistent with hypoxia-induced ACE2 upregulation. SARS-CoV-2 showed a similar preferential localization to trophoblastic cells of fibrin-encased villi., Discussion: The localization of SARS-CoV-2 to hypoxic, fibrin-encased villi in this placenta with CHIV/MPVFD suggests placental infection and, therefore, transplacental SARS-CoV-2 transmission may be promoted by hypoxic conditions, mediated by ACE2 and similar hypoxia-sensitive viral cell entry mechanisms. Understanding of a causative link between placental hypoxia and SARS-CoV-2 transmittability may potentially lead to the development of alternative strategies for prevention of intrauterine COVID-19 transmission., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Standard biomarkers have been widely used for COVID-19 diagnosis and prognosis. We hypothesize that thrombogenicity metrics measured by thromboelastography will provide better diagnostic and prognostic utility versus standard biomarkers in COVID-19 positive patients. In this observational prospective study, we included 119 hospitalized COVID-19 positive patients and 15 COVID-19 negative patients. On admission, we measured standard biomarkers and thrombogenicity using a novel thromboelastography assay (TEG-6s). In-hospital all-cause death and thrombotic occurrences (thromboembolism, myocardial infarction and stroke) were recorded. Most COVID-19 patients were African--Americans (68%). COVID-19 patients versus COVID-19 negative patients had higher platelet-fibrin clot strength (P-FCS), fibrin clot strength (FCS) and functional fibrinogen level (FLEV) (P ≤ 0.003 for all). The presence of high TEG-6 s metrics better discriminated COVID-19 positive from negative patients. COVID-19 positive patients with sequential organ failure assessment (SOFA) score at least 3 had higher P-FCS, FCS and FLEV than patients with scores less than 3 (P ≤ 0.001 for all comparisons). By multivariate analysis, the in-hospital composite endpoint occurrence of death and thrombotic events was independently associated with SOFA score more than 3 [odds ratio (OR) = 2.9, P = 0.03], diabetes (OR = 3.3, P = 0.02) and FCS > 40 mm (OR = 3.4, P = 0.02). This largest observational study suggested the early diagnostic and prognostic utility of thromboelastography to identify COVID-19 and should be considered hypothesis generating. Our results also support the recent FDA guidance regarding the importance of measurement of whole blood viscoelastic properties in COVID-19 patients. Our findings are consistent with the observation of higher hospitalization rates and poorer outcomes for African--Americans with COVID-19., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Fibrin-associated diffuse large B cell lymphoma (FA-DLBCL) is a rare Epstein-Barr viruspositive B cell lymphoma that is nonmass-forming, does not directly produce symptoms, and is incidentally discovered on histological examination of tissues excised for other reasons. Despite overlap in morphologic and immunophenotypic features with aggressive B cell neoplasms, FA-DLBCL shows an excellent clinical outcome, even with surgical excision alone. We report an extremely rare occurrence of FA-DLBCL found in association with a metallic implant on revision arthroplasty of the knee. This report also illustrates the need for an integrated multidisciplinary approach for accurate diagnosis and avoidance of overtreatment.

In kidney transplantation, microthrombi and fibrin deposition may lead to local perfusion disorders and subsequently poor initial graft function. Microthrombi are often regarded as donor-derived. However, the incidence, time of development, and potential difference between living donor kidneys (LDK) and deceased donor kidneys(DDK), remains unclear. Two open-needle biopsies, taken at preimplantation and after reperfusion, were obtained from 17 LDK and 28 DDK transplanted between 2005 and 2008. Paraffin-embedded sections were immunohistochemically stained with anti-fibrinogen antibody. Fibrin deposition intensity in peritubular capillaries(PTC) and glomeruli was categorized as negative, weak, moderate or strong and the number of microthrombi/mm 2 was quantified. Reperfusion biopsies showed more fibrin deposition (20% to 100% moderate/strong, p < 0.001) and more microthrombi/mm 2 (0.97 ± 1.12 vs. 0.28 ± 0.53, p < 0.01) than preimplantation biopsies. In addition, more microthrombi/mm 2 (0.38 ± 0.61 vs. 0.09 ± 0.22, p = 0.02) and stronger fibrin intensity in glomeruli (28% vs. 0%, p < 0.01) and PTC (14% vs. 0%, p = 0.02) were observed in preimplantation DDK than LDK biopsies. After reperfusion, microthrombi/mm 2 were comparable (p = 0.23) for LDK (0.09 ± 0.22 to 0.76 ± 0.49, p = 0.03) and DDK (0.38 ± 0.61 to 0.90 ± 1.11, p = 0.07). Upon reperfusion, there is an aggravation of microthrombus formation and fibrin deposition within the graft. The prominent increase of microthrombi in LDK indicates that they are not merely donor-derived., (© 2021. The Author(s).)

Objective: The aim of the present study was to determine whether there is a correlation between thrombotic pathology and prognosis of endovascular treatment (EVT) for acute ischemic stroke (AIS)., Methods: Thrombi were taken from 58 patients with cerebral ischemic thrombosis who were consecutively selected for EVT for AIS. The collected thrombi then underwent hematoxylin-eosin staining for pathological examinations to determine the red blood cell (RBC) ratio and fibrin/platelet components. The patients were divided into the following three groups according to their proportions of RBCs in thrombi: RBC-rich group (RBC ratio ≥ 70%), mixed group (RBC ratio at 31-69%), and fibrin/platelet-rich group (RBC ratio ≤ 30%). Prognosis was classified into good (0-2 points on modified Rankin scale [mRS] at postoperative 90 days) and poor (3-6 points on mRS at postoperative 90 days). Correlational analysis was performed between thrombotic pathology and prognosis of EVT for AIS., Results: Among all patients, the distributions were as follows: 18.96% (11/58) patients in the RBC-rich group, 63.79% (37/58) patients in the mixed group, and 17.24% (10/58) patients in the fibrin/platelet-rich group. In addition, 43.10% (25/58) of the patients had good prognosis and 56.90% (33/58) had poor prognosis.There was no statistically significant difference between the good prognosis and the poor prognosis in the RBC-rich group, the mixed group, and the fibrin/platelet-rich group (P=0.713, 0.829, 0.748).Multivariate logistic regression analysis to explored the association between RBC-rich group and good prognosis while adjusting for other baseline prognostic factors (age, ASPECTS, NIHSS score, and PRT and intravenous alteplase-bridging therapy). Compared to the fibrin/platelet-rich group, the odds ratio(OR) of achieving good prognosis was 0.60 (P = 0.592) for the mixed group and OR = 0.74 (P = 0.793) for the RBC-rich group.Notably, age was found to be negatively associated with good prognosis (OR = 0.91, P = 0.013). The ASPECTS score was found to be positively associated with good prognosis (OR = 2.01, P = 0.002). Alteplase bridging was associated with a marginally significant positive association with good prognosis (OR = 4.23, P = 0.083)., Conclusions: No correlation was found between thrombotic pathology and prognosis of EVT for AIS. Good prognosis after endovascular treatment was associated with low age, high ASPECTS at admission, and alteplase bridging., Competing Interests: Declaration of Competing Interests The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2021. Published by Elsevier Inc.)

Introduction: Fibrin/fibrinogen degradation products (FDP) values reflect coagulation and fibrinolysis status, and FDP levels are helpful for diagnosis and classification of disseminated intravascular coagulation (DIC). FDP measurement has always played a key role in diagnosing DIC, a phenomenon that has recently gained renewed attention because of its occurrence in coronavirus disease 2019 (COVID-19) patients. Although the evaluation of FDP is crucial for the management of critical care, the variability among FDP reagents is unclear. In this study, we aimed to compare LIASAUTO P-FDP with three FDP reagents and investigate their characteristics., Methods: In total, 172 plasmas samples were used in the correlation. The sample data were divided into three groups including negative, no and positive discrepancy based on the discrepancy percentages calculated from each correlation between LIASAUTO P-FDP and other three reagents. D-dimer, plasmin-α 2 plasmin inhibitor complex (PIC), fibrin monomer complex (FMC), fibrinogen (Fbg) and Plasmin-α 2 Plasmin Inhibitor (α 2 PI) were measured and included in data analysis., Results: The positive discrepancy groups showed higher D-dimer, PIC and FMC values than the negative discrepancy groups. The data indicated that LIASAUTO P-FDP had higher reactivity to D-dimer than other reagents and the values were elevated in the fibrinolysis-enhanced samples with various FDP fragments., Conclusion: LIASAUTO P-FDP displayed the reactivity towards various fibrin/fibrinogen degradation products, and it might be useful for DIC diagnosis because the fibrinolytic status differed in the DIC types and stages., (© 2020 John Wiley & Sons Ltd.)

Background: We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients to study the association between histological composition and stroke etiology METHODS: Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using martius scarlet blue (MSB) staining, and quantification for red blood cells (RBCs), white blood cells (WBCs), fibrin and platelets was performed using Orbit Image Software. A Wilcoxon test was used for continuous variables and χ 2 test for categorical variables., Results: 1350 patients were included in this study. The overall rate of Thrombolysis In Cerebral Infarction (TICI) 2c/3 was 68%. 501 patients received tissue plasminogen activator (tPA) (37%). 267 patients (20%) had a large artery atherosclerosis (LAA) source, 662 (49%) a cardioembolic (CE) source, 301 (22%) were cryptogenic, and the remainder had other identifiable sources including hypercoagulable state or dissection. LAA thrombi had a higher mean RBC density (46±23% vs 42±22%, p=0.01) and a lower platelet density (24±18% vs 27±18%, p=0.03) than CE thrombi. Clots from dissection patients had the highest mean RBC density (50±24%) while clots from patients with a hypercoagulable state had the lowest mean RBC density (26±21%)., Conclusions: Our study found statistically significant but clinically insignificant differences between clots of CE and LAA etiologies. Future studies should emphasize molecular, proteomic and immunohistochemical characteristics to determine links between clot composition and etiology., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The association of carotid webs (CaW) and ischemic stroke is being increasingly recognized. Data on the histologic clot architecture in strokes caused by CaW has not been previously described. Understanding thrombi histopathology may provide insight into the pathophysiology of CaW-related strokes., Methods: This case series presents three patients with acute ischemic stroke thought to be caused by ipsilateral CaW. Thromboemboli were retrieved from the middle cerebral artery (MCA) by mechanical thrombectomy and histologic analysis was performed., Results: Three patients aged between 41 and 55 years with few to no vascular risk factors presented with symptoms concerning for an acute MCA territory infarction (National Institutes of Health Stroke Scale (NIHSS) range 10-17). Non-contrast computed tomography (CT) Alberta Stroke Program Early CT Score (ASPECTS) range was 7-8 and all patients had hyperdense vessel sign. Initial CT angiogram was concerning for CaW with no superimposed thrombus, later confirmed with conventional angiography. All patients underwent thrombectomy with full reperfusion. Comprehensive stroke workup failed to reveal other etiologies besides ipsilateral CaW. The histopathologic appearance was of typical fresh mixed thrombi. Qualitative thrombus composition analysis of clot from Case #1 yielded 42.5% fibrin, 50.0% red blood cells (RBC), and 7.5% white blood cells (WBC); Case #2 yielded 46.9% fibrin, 43.4% RBC, and 9.7% WBC; and Case #3 yielded 61.5% fibrin, 31.8% RBC, and 6.7% WBC., Conclusions: The clot composition of large vessel occlusion strokes from CaW is comparable to the histopathology of previously reported clots from other stroke etiologies. Advanced staining techniques may aid in further characterizing the thrombi of this poorly understood condition., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Fibrinolysis is an important process in hemostasis responsible for dissolving the clot during wound healing. Plasmin is a central enzyme in this process via its capacity to cleave fibrin. The kinetics of plasmin generation (PG) and inhibition during fibrinolysis have been poorly understood until the recent development of assays to quantify these metrics. The assessment of plasmin kinetics allows for the identification of fibrinolytic dysfunction and better understanding of the relationships between abnormal fibrin dissolution and disease pathogenesis. Additionally, direct measurement of the inhibition of PG by antifibrinolytic medications, such as tranexamic acid, can be a useful tool to assess the risks and effectiveness of antifibrinolytic therapy in hemorrhagic diseases. This review provides an overview of available PG assays to directly measure the kinetics of plasmin formation and inhibition in human and mouse plasmas and focuses on their applications in defining the role of plasmin in diseases, including angioedema, hemophilia, rare bleeding disorders, COVID-19, or diet-induced obesity. Moreover, this review introduces the PG assay as a promising clinical and research method to monitor antifibrinolytic medications and screen for genetic or acquired fibrinolytic disorders.

Diseases such as myocardial infarction, ischaemic stroke, peripheral vascular disease and venous thromboembolism are major contributors to morbidity and mortality. Procoagulant, anticoagulant and fibrinolytic pathways are finely regulated in healthy individuals and dysregulated procoagulant, anticoagulant and fibrinolytic pathways lead to arterial and venous thrombosis. In this review article, we discuss the (patho)physiological role and laboratory assessment of fibrin, factor XIII and endogenous fibrinolysis, which are key players in the terminal phase of the coagulation cascade and fibrinolysis. Finally, we present the most up-to-date evidence for their involvement in various disease states and assessment of cardiovascular risk.

Arterial thrombus formation is thought to be initiated by platelet adhesion to the subendothelial matrix, but ruptured atherosclerotic plaques are characterized by substantial reduction of matrix proteins compared with stable plaques. Intraplaque erythrocytes and/or fibrin have been reported in high-risk coronary plaques. The aims of the current study were to identify factors that provide scaffolds for platelets at the sites of ruptured coronary plaques and investigate depositions of iron and bilirubin as hemoglobin catabolites in the ruptured plaques. Histological characteristics of plaque components and the thrombus interface were examined in 73 acute coronary aspirated thrombi. Necrotic debris (95%), macrophages (95%), and cholesterin clefts (81%) were observed frequently at the ruptured plaque and thrombus interface. A fibrous matrix (47%), calcification (32%), and extracellular deoxyribonucleic acid (15%) were identified as small foci. Tissue factor was localized in the necrotic core and macrophages. Fibrin and von Willebrand factor were consistently deposited within the plaques and beneath platelet aggregations. The citrullinated histone H3-immunopositive area accounted for only 0.5% of the plaque area. Bilirubin and iron depositions were detected in approximately 20% of the plaques in addition to biliverdin reductase and ferritin expression in macrophages. Fibrin and von Willebrand factor rather than matrix proteins and neutrophil extracellular traps may be major adhesive molecules at the sites of ruptured plaques. Iron and bilirubin deposits may be markers for rupture-prone plaques., Competing Interests: None declared., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Haematological malignancies, including acute leukaemia and non-Hodgkin lymphoma, are one of the underlying diseases that frequently cause disseminated intravascular coagulation (DIC), an acquired thrombotic disorder. Concomitant DIC is associated with the severity of the underlying disease and poor prognosis. The Japanese Society on Thrombosis and Hemostasis released the new DIC diagnostic criteria in 2017. This criteria include coagulation markers such as soluble fibrin and the thrombin-antithrombin complex to more accurately evaluate the hypercoagulable state in patients. Among several groups of anticoagulants available, recombinant human soluble thrombomodulin is most frequently used to treat DIC caused by haematological malignancies in Japan. DIC is remitted in parallel with the improvement of the underlying haematological diseases; thus, there is room for debate regarding whether the treatment of DIC would improve the prognosis of patients. Haematopoietic stem cell transplantation as well as the recently introduced chimeric antigen receptor (CAR)-T-cell therapy are innovative therapies to produce a cure in a subset of patients with haematological malignancies. However, coagulopathy frequently occurs after these therapies, which limits the success of the treatment. For example, DIC is noted in approximately 50% of patients after CAT-T-cell therapy in conjunction with cytokine release syndrome. Hematopoietic stem cell transplantation (HSCT) causes endotheliitis, which triggers coagulopathy and the development of potentially lethal complications, such as sinusoidal obstruction syndrome/veno-occlusive disease and transplant-associated thrombotic microangiopathy. This review article describes the pathogenesis, clinical manifestation, diagnosis, and treatment of DIC caused by haematological malignancies, CAR-T-cell therapy, and HSCT.

Background and Purpose: Clot perviousness in acute ischemic stroke is a potential CT imaging biomarker for mechanical thrombectomy efficacy. We investigated the association among perviousness, clot cellular composition, and first-pass effect., Materials and Methods: In 40 mechanical thrombectomy-treated cases of acute ischemic stroke, we calculated perviousness as the difference in clot density on CT angiography and noncontrast CT. We assessed the proportion of fibrin/platelet aggregates, red blood cells, and white blood cells on clot histopathology. We tested for linear correlation between histologic components and perviousness, differences in components between "high" and "low" pervious clots defined by median perviousness, and differences in perviousness/composition between cases that did and did not achieve a first-pass effect., Results: Perviousness significantly positively and negatively correlated with the percentage of fibrin/platelet aggregates ( P  = .001) and the percentage of red blood cells ( P  = .001), respectively. Higher pervious clots had significantly greater fibrin/platelet aggregate content ( P  = .042). Cases that achieved a first-pass effect ( n  = 14) had lower perviousness, though not significantly ( P = .055). The percentage of red blood cells was significantly higher ( P  = .028) and the percentage of fibrin/platelet aggregates was significantly lower ( P  = .016) in cases with a first-pass effect. There was no association between clot density on NCCT and clot composition or first-pass effect. Receiver operating characteristic analysis indicated that clot composition was the best predictor of first-pass effect (area under receiver operating characteristic curve: percentage of fibrin/platelet aggregates  = 0.731, percentage of red blood cells  = 0.706, perviousness = 0.668)., Conclusions: Clot perviousness on CT is associated with a higher percentage of fibrin/platelet aggregate content. Histologic data and, to a lesser degree, perviousness may have value in predicting first-pass outcome. Imaging metrics that more strongly reflect clot biology than perviousness may be needed to predict a first-pass effect with high accuracy., (© 2021 by American Journal of Neuroradiology.)

Background: Fibrin network characteristics determine predisposition to cardiovascular disease (CVD). Individuals with type 1 (T1DM) and type 2 diabetes mellitus (T2DM) have higher risk of CVD and display deranged fibrin network structure. Those with maturity onset diabetes of the young (MODY) may also be at increased risk but their fibrin clot properties have not been studied., Methods: Plasma clots properties from 13 individuals with HNF1A-MODY, 12 matched-individuals with T2DM and 12 with T1DM were studied using a validated turbidimetric assay and confocal microscopy. Plasma levels of fibrinogen, plasminogen activator inhibitor-1, complement C3 and C-reactive protein were also measured., Results: MODY clot maximum absorbance was 0.37 ± 0.03 AU, similar to T1DM (0.32 ± 0.03 AU; p  = 0.26), but lower than T2DM (0.49 ± 0.03 AU; p  = 0.02), with confocal microscopy confirming structural differences. Clot lysis time in MODY was similar to T1DM (456 ± 50 and 402 ± 20 s, respectively; p  = 0.09) but shorter than T2DM (588 ± 58 s; p  = 0.006). Comparing inflammatory/thrombotic proteins in HNF1A-MODY and T2DM, C3 levels were lower in MODY than T2DM (0.58 ± 0.09 and 0.80 ± 0.1 mg/ml, respectively; p  < 0.01)., Conclusions: HNF1A-MODY fibrin network alterations are at least as pronounced as in T1DM but less thrombotic than T2DM clots. Differences in fibrin clot characteristics comparing HNF1A-MODY and T2DM may, in part, relate to lower C3 levels.

We report a 60-year-old male with fibrin-associated diffuse large B-cell lymphoma (fa-DLBCL) in left atrial myxoma. Echocardiography showed a mass (63 mm × 33 mm) in the left atrium. Histological inspection indicated fa-DLBCL on the surface of atrial myxoma incidentally, together with extensive fibrinous like exudation on myxoma surface. Malignant cells were localized in solid sheets and nests at the peripheral area of the fibrinous exudation which were positive for B-lineage markers (CD20+, CD79a+, PAX-5+) and in situ hybridization of EBV-encoded RNA (EBER). PCR amplification showed clonal rearrangement of immunoglobulin heavy chain (IgH) genes. The patient was still alive with no recurrence in the 35-month follow-up after surgery. We also did a detailed clinicopathological analysis and literature review, which indicated that fa-DLBCL was a heterogeneous entity., (Copyright © 2020. Published by Elsevier Inc.)

Infectious endocarditis (IE) remains one of the deadliest heart diseases with a high death rate, generally following thrombo-embolic events. Today, therapy is based on surgery and antibiotic therapy. When thromboembolic complications in IE patients persist, this is often due to our lack of knowledge regarding the pathophysiological development and organization of cells in the vegetation, most notably the primordial role of platelets and further triggered hemostasis, which is related to the diversity of infectious microorganisms involved. Our objective was to study the organization of IE vegetations due to different bacteria species in order to understand the related pathophysiological mechanism of vegetation development. We present an approach for ultrastructural analysis of whole-infected heart valve tissue based on scanning electron microscopy and energy-dispersive X-ray spectroscopy. Our approach allowed us to detect differences in cell organization between the analyzed vegetations and revealed a distinct chemical feature in viridans Streptococci ones. Our results illustrate the benefits that such an approach may bring for guiding therapy, considering the germ involved for each IE patient.

End-stage renal disease (ESRD) is a condition accompanied by increased inflammation, oxidative stress, risk of cardiovascular complications, and coagulopathies. The structure of fibrinogen and characteristics of fibrin from plasma samples of ESRD patients on peritoneal dialysis (PD) was investigated. Fibrinogen from ESRD patients had a higher degree of carbonylation than fibrinogen from healthy individuals. The Aα chain was the most susceptible to oxidation, followed by the Bβ chain, whereas the γ-chain was the most resistant to oxidation. Spectrofluorimetric analysis suggested a higher extent of modification of amino acid side chains in fibrinogen from ESRD patients. The tertiary structure of fibrinogen was more affected than its secondary structure. The kinetics (time and rate) of fibrinogen coagulation did not differ between the tested groups. Fibrin prepared from the isolated fibrinogen had a similar structure in both groups. Our results confirm that oxidation and structural alterations of fibrinogen occur in ESRD patients on PD, although these modifications produce no direct effect on the fibrin formation. Taking into account that some patients suffer from bleeding, whereas others develop thrombotic complications, further research on this subject is required to identify other components and processes that contribute to the outcome.

Context: The thrombotic effects of estradiol therapy in transgender women are unclear. Global coagulation assays (GCA) may be better measures of hemostatic function compared with standard coagulation tests., Objective: To assess the GCA profiles of transgender women in comparison to cisgender controls and to compare how GCA differ between routes of estradiol therapy in transgender women., Design: Cross-sectional case-control study., Setting: General community., Participants: Transgender women, cisgender male and cisgender female controls., Main Outcome Measures: Citrated blood samples were analyzed for (i) whole blood thromboelastography (TEG®5000), (ii) platelet-poor plasma thrombin generation (calibrated automated thrombogram); and (iii) platelet-poor plasma fibrin generation (overall hemostatic potential assay). Mean difference (95% confidence intervals) between groups are presented., Results: Twenty-six transgender women (16 oral estradiol, 10 transdermal estradiol) were compared with 98 cisgender women and 55 cisgender men. There were no differences in serum estradiol concentration (P = 0.929) and duration of therapy (P = 0.496) between formulations. Transgender women demonstrated hypercoagulable parameters on both thromboelastography (maximum amplitude + 6.94 mm (3.55, 10.33); P < 0.001) and thrombin generation (endogenous thrombin potential + 192.62 nM.min (38.33, 326.91); P = 0.009; peak thrombin + 38.10 nM (2.27, 73.94); P = 0.034) but had increased overall fibrinolytic potential (+4.89% (0.52, 9.25); P = 0.024) compared with cisgender men. No significant changes were observed relative to cisgender women. Route of estradiol delivery or duration of use did not influence the GCA parameters., Conclusion: Transgender women on estradiol therapy demonstrated hypercoagulable GCA parameters compared with cisgender men with a shift towards cisgender female parameters. Route of estradiol delivery did not influence the GCA parameters., (© Endocrine Society 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Platelet-rich fibrin (PRF) is a fibrin matrix enriched with platelets. The PRF matrix is thought to form a steep gradient of platelet density around the region corresponding to the buffy coat in anticoagulated blood samples. However, this phenomenon has not yet been proven. To visualize platelet distribution in PRF in a non-invasive manner, we utilized near-infrared (NIR) imaging technology. In this study, four types of PRF matrices, bio-PRF, advanced-PRF (A-PRF), leukocyte-rich PRF (L-PRF), and concentrated growth factors (CGF) were compared. Blood samples collected from healthy, non-smoking volunteers were immediately centrifuged using four different protocols in glass tubes. The fixed PRF matrices were sagittally divided into two equal parts, and subjected to modified immunohistochemical examination. After probing with NIR dye-conjugated secondary antibody, the CD41 + platelets were visualized using an NIR imager. In L-PRF and CGF, platelets were distributed mainly on and below the distal surface, while in bio-PRF and A-PRF, platelet distribution was widespread and homogenous. Among three regions of the PRF matrices (upper, middle, and lower), no significant differences were observed. These findings suggest that platelets aggregate on polymerizing fibrin fibers and float up as a PRF matrix into the plasma fraction, amending the current "gradient" theory of platelet distribution.

In late December 2019 an outbreak of a novel coronavirus (SARS-CoV-2) causing severe pneumonia (COVID-19) was reported in Wuhan, Hubei Province, China. A common finding in most COVID-19 patients is high D-dimer levels which are associated with a worse prognosis. We aimed to evaluate coagulation abnormalities via traditional tests and whole blood thromboelastometry profiles in a group of 22 (mean age 67 ± 8 years, M:F 20:2) consecutive patients admitted to the Intensive Care Unit of Padova University Hospital for acute respiratory failure due to COVID-19. Cases showed significantly higher fibrinogen and D-dimer plasma levels versus healthy controls ( p  < 0.0001 in both comparisons). Interestingly enough, markedly hypercoagulable thromboelastometry profiles were observed in COVID-19 patients, as reflected by shorter Clot Formation Time (CFT) in INTEM ( p  = 0.0002) and EXTEM ( p  = 0.01) and higher Maximum Clot Firmness (MCF) in INTEM, EXTEM and FIBTEM ( p  < 0.001 in all comparisons). In conclusion, COVID-19 patients with acute respiratory failure present a severe hypercoagulability rather than consumptive coagulopathy. Fibrin formation and polymerization may predispose to thrombosis and correlate with a worse outcome., Competing Interests: None declared., (Georg Thieme Verlag KG Stuttgart · New York.)

Objectives: Platelet-rich fibrin (PRF) procuring protocols have been suggested, differing in speed and time duration. Since different derivation protocols may alter PRF characteristics, the present study was conducted to evaluate the variations in the fibrin network pattern, platelet count, and antimicrobial efficacy of PRF procured using variable centrifugation speeds and time durations in different age groups., Materials and Methods: Sixty healthy subjects participated in the study and were equally divided into three age groups (20-34 years, 35-49 years, 50-65 years). From each age group, total of 6 PRF membranes were fabricated from 10 ml tubes. Three PRF membranes were obtained at 1400, 2800, and 3500 rpm for 8 min while other 3 membranes were obtained after 15 min of centrifugation respectively. The relative centrifugal force (RCF) values were within the spectrum of 228-1425 g. PRF membranes were then subjected to platelet count estimation, antimicrobial activity against oral bacteria, and changes in fibrin network pattern with respect to different age groups and different centrifugation protocols., Results: Highest platelet concentration, antimicrobial activity, and dense fibrin network were obtained in 20-34 years age group. Intragroup analysis within each group revealed highest platelet count and antimicrobial activity in PRF membranes, obtained at 1400 rpm for 8 min. Denser fibrin network pattern was demonstrated by PRF membranes procured at 3500 rpm for 15 min., Conclusions: PRF properties, i.e., platelet count, antimicrobial efficacy, and fibrin network, are influenced by technical aspects of PRF preparation (RCF value, centrifugation speed, and time) and patient age., Clinical Relevance: Based on the finding of present study, it can be implied that lower centrifugation speed and time can increase the platelet concentration and antimicrobial activity of the PRF membrane. Contrarily, lowering the speed and time leads to lesser density fibrin network pattern. Centrifugation protocols thus need to be adapted accordingly.

Background and Aims: Despite the presence of neutrophil extracellular traps [NETs] in inflamed colon having been confirmed, the role of NETs, especially the circulating NETs, in the progression and thrombotic tendency of inflammatory bowel disease [IBD] remains elusive. We extended our previous study to prove that NETs constitute a central component in the progression and prothrombotic state of IBD., Methods: In all 48 consecutive patients with IBD were studied. Acute colitis was induced by the treatment of C57BL/6 mice with 3.5% dextran sulphate sodium [DSS] in drinking water for 6 days. Peripheral blood neutrophils and sera were collected from IBD patients and murine colitis models. Exposed phosphatidylserine [PS] was analysed with flow cytometry and confocal microscopy. Procoagulant activity was evaluated using clotting time, purified coagulation complex, and fibrin formation assays., Results: We observed higher plasma NET levels and presence of NETs in colon tissue in patients with active IBD. More importantly, NETs were induced in mice with DSS colitis, and inhibition of NET release attenuated colitis as well as colitis-associated tumorigenesis. NET degradation through DNase administration decreased cytokine levels during DSS-induced colitis. In addition, DNase treatment also significantly attenuated the accelerated thrombus formation and platelet activation observed in DSS-induced colitis. NETs triggered PS-positive microparticle release and PS exposure on platelets and endothelial cells partially through TLR2 and TLR4, converting them to a procoagulant phenotype., Conclusions: NETs exacerbate colon tissue damage and drive thrombotic tendency during active IBD. Strategies directed against NET formation may offer a potential therapeutic approach for the treatment of IBD., (Copyright © 2019 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Individuals with type-1 diabetes mellitus (T1DM) have a higher risk of thrombosis and low plasma magnesium concentrations. As magnesium is a known regulator of fibrin network formation, we investigated potential associations between fibrin clot properties and plasma magnesium concentrations in 45 individuals with T1DM and 47 age- and sex-matched controls without diabetes. Fibrin clot characteristics were assessed using a validated turbidimetric assay and associations with plasma magnesium concentration were examined. Plasma concentrations of fibrinogen, plasminogen activator inhibitor-1 (PAI-1), and lipids were measured and fibrin fiber diameters assessed using scanning electron microscopy. Fibrin clot maximum absorbance was unchanged in subjects with T1DM compared with controls, while lysis time was prolonged ( p  = 0.0273). No differences in fibrin fiber diameters or in lipid profile were observed between T1DM and controls. PAI-1 concentration was lower in the T1DM group compared with the controls ( p  = 0.0232) and positively correlated with lysis time ( p  = 0.0023). Plasma magnesium concentration was lower in the T1DM group compared with controls ( p  < 0.0001). Magnesium concentration negatively correlated with clot maximum absorbance ( p  = 0.0215) and lysis time ( p  = 0.0464). A turbidimetric fibrin clot lysis assay performed in a purified system that included PAI-1 and 0 to 3.2 mM Mg 2+ showed a shortening of lysis time with increasing Mg 2+ concentrations ( p  = 0.0004). Our findings reveal that plasma magnesium concentration is associated with changes in fibrin clot and lysis parameters., Competing Interests: None declared., (Georg Thieme Verlag KG Stuttgart · New York.)

Aim: Idiopathic normal pressure hydrocephalus (iNPH) is one subtype of dementia characterized by cerebrospinal fluid (CSF) disturbance, but with unknown cause. We recently reported that frontal cortex biopsies of iNPH patients disclosed degenerative alterations of the capillary basement membrane, including degenerated pericyte processes. Given that pericyte degeneration is associated with blood-brain barrier (BBB) dysfunction, the present study was undertaken to examine whether BBB leakage of blood proteins can be revealed by light microscopy (LM) immunohistochemistry in iNPH., Methods: The study included cortical brain tissue specimens from 14 reference (REF) subjects undergoing neurosurgery for epilepsy, aneurysm or tumor, and 45 iNPH patients. Dysfunction of the BBB was measured semi-quantitatively as area percentage extravasated fibrin(ogen) in cerebral cortical layers I, II and III. The degree of fibrin(ogen) extravasation was also correlated with expression of glial fibrillary acidic protein (GFAP), aquaporin-4 (AQP4), dystrophin 71 (Dp71) and Cluster of Differentiation 68 (CD68)., Results: The study disclosed extravasation of fibrin(ogen) in 4/14 REF subjects and in 45/45 iNPH patients, the percentage area of fibrin(ogen) was significantly higher in iNPH than REF cortical specimens. Diffuse, less prominent fibrin(ogen) extravasation was seen in the subcortical white matter of one iNPH individual. Increasing degree of fibrinogen extravasation in cerebral cortex was significantly associated with increasing degree of astrogliosis and with reduced expression of perivascular AQP4 and Dp71., Conclusions: The present results provide evidence of BBB dysfunction in iNPH. The BBB leakage of blood proteins may render for impaired neurovascular units in iNPH patients., (Copyright © 2019 The Author(s). Published by Elsevier B.V. All rights reserved.)

Competing Interests: None declared.

Background: Current studies on clot characterization in acute ischemic stroke focus on fibrin and red blood cell composition. Few studies have examined platelet composition in acute ischemic stroke clots. We characterize clot composition using the Martius Scarlet Blue stain and assess associations between platelet density and CT density., Materials and Method: Histopathological analysis of the clots collected as part of the multi-institutional STRIP registry was performed using Martius Scarlet Blue stain and the composition of the clots was quantified using Orbit Image Analysis (www.orbit.bio) machine learning software. Prior to endovascular treatment, each patient underwent non-contrast CT (NCCT) and the CT density of each clot was measured. Correlations between clot components and clinical information were assessed using the χ 2 test., Results: Eighty-five patients were included in the study. The mean platelet density of the clots was 15.7% (2.5-72.5%). There was a significant correlation between platelet-rich clots and the absence of hyperdensity on NCCT, (ρ=0.321, p=0.003*, n=85). Similarly, there was a significant inverse correlation between the percentage of platelets and the mean Hounsfield Units on NCCT (ρ=-0.243, p=0.025*, n=85)., Conclusion: Martius Scarlet Blue stain can identify patients who have platelet-rich clots. Platelet-rich clots are isodense on NCCT., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)