Elevated Lactate Levels in Acute Pulmonary Embolism Are Associated with Prothrombotic Fibrin Clot Properties: Contribution of NETs Formation

Highly catalytic Prussian blue analogues and their application on the three-dimensional origami paper-based sweat sensors

Prussian blue analogues (PBAs) are promising materials due to their rich active sites and straightforward synthesis. However, their limited conductivity and electron transfer inefficiency hinder practical applications. This study utilizes a simple one-pot synthesis approach to produce a tungsten-disulfide (WS2) and iron-cobalt Prussian blue analogue composite (WS2-PBA), enhancing conductivity and electron transfer rate performance. Through the inclusion of sodium citrate into the solution, the S-edge site concentration of WS2 increases. This augmentation introduces additional active sites and defects into the catalyst, enhancing its catalytic activity. The effectiveness of the WS2-PBA 3D-Origami paper device for lactate detection in sweat is also evaluated for biomedical applications. The device demonstrated a robust relationship between the lactate concentration and current intensity (R2 = 0.997), with a detection limit of 1.83 mM. Additionally, this platform has successfully detected lactate in clinical sweat, correlating with the high-performance liquid chromatography test results, suggesting promising prospects for clinical diagnosis. In the future, the excellent catalytic and Rct performance of the WS2-PBA will enable its use in biomedical applications.

Management of Venous and Arterial Thrombosis

A thrombus is a hemostatic plug localized in a blood vessel [...].

Early predictors of clinical deterioration in intermediate-high risk pulmonary embolism: clinical needs, research imperatives, and pathways forward

A subset of intermediate-high risk pulmonary embolism (PE) patients will suffer clinical deterioration in the early hours following the acute event. Current evidence-based guidelines for the management of acute PE have provided limited direction for identification of which intermediate-high risk PE patients will go on to develop haemodynamic decompensation. Furthermore, a paucity of data further hampers guideline recommendations regarding the optimal approach and duration of intensive monitoring, best methods to assess the early response to anticoagulation, and the ideal window for reperfusion therapy, if decompensation threatens. The aim of the present article is to identify the current unmet needs related to the early identification of intermediate-high risk PE patients at higher risk of clinical deterioration and mortality during the early hours after the acute cardiovascular event and suggest some potential strategies to further explore gaps in the literature.

Influence of Diameter and Cyclic Mechanical Stimulation on the Beating Frequency of Myocardial Cell-Laden Fibers

Atrioventricular block (AVB) is a severe disease for pediatric patients. The repetitive operations needed in the case of the pacemaker implantation to maintain the electrical signal at the atrioventricular node (AVN) affect the patient's life quality. In this study, we present a method of biofabrication of multi-cell-laden cylindrical fibrin-based fibers that can restore the electrical signal at the AVN. We used human umbilical vein smooth muscle cells (HUVSMCs), human umbilical vein endothelial cells (HUVECs) and induced pluripotent stem cell cardiomyocytes (iPSC-CMs) cultivated either statically or dynamically to mimic the native AVN. We investigated the influence of cell composition, construct diameter and cyclic stretch on the function of the fibrin hydrogels in vitro. Immunohistochemistry analyses showed the maturity of the iPSC-CMs in the constructs through the expression of sarcomeric alpha actinin (SAA) and electrical coupling through Connexin 43 (Cx43) signal. Simultaneously, the beating frequency of the fibrin hydrogels was higher and easy to maintain whereas the concentration of iPSC-CMs was higher compared with the other types of cylindrical constructs. In total, our study highlights that the combination of fibrin with the cell mixture and geometry is offering a feasible biofabrication method for tissue engineering approaches for the treatment of AVB.

Metabolic alterations upon SARS-CoV-2 infection and potential therapeutic targets against coronavirus infection

The coronavirus disease 2019 (COVID-19) caused by coronavirus SARS-CoV-2 infection has become a global pandemic due to the high viral transmissibility and pathogenesis, bringing enormous burden to our society. Most patients infected by SARS-CoV-2 are asymptomatic or have mild symptoms. Although only a small proportion of patients progressed to severe COVID-19 with symptoms including acute respiratory distress syndrome (ARDS), disseminated coagulopathy, and cardiovascular disorders, severe COVID-19 is accompanied by high mortality rates with near 7 million deaths. Nowadays, effective therapeutic patterns for severe COVID-19 are still lacking. It has been extensively reported that host metabolism plays essential roles in various physiological processes during virus infection. Many viruses manipulate host metabolism to avoid immunity, facilitate their own replication, or to initiate pathological response. Targeting the interaction between SARS-CoV-2 and host metabolism holds promise for developing therapeutic strategies. In this review, we summarize and discuss recent studies dedicated to uncovering the role of host metabolism during the life cycle of SARS-CoV-2 in aspects of entry, replication, assembly, and pathogenesis with an emphasis on glucose metabolism and lipid metabolism. Microbiota and long COVID-19 are also discussed. Ultimately, we recapitulate metabolism-modulating drugs repurposed for COVID-19 including statins, ASM inhibitors, NSAIDs, Montelukast, omega-3 fatty acids, 2-DG, and metformin.

Predictive Model for Pulmonary Embolism in Pregnant and Postpartum Women: A 10-Year Retrospective Study

Background: Pulmonary embolism (PE) in pregnant and postpartum women is fatal, and risk assessment is crucial for effective and safe management, the aim of this retrospective study was to establish a nomogram for predicting the risk of PE in pregnant and postpartum women. Methods: Totally 343 subjects suspected of PE at the Obstetrics Department of Affiliated Dongyang Hospital of Wenzhou Medical University from January 2012 to December 2021 were retrospective analyzed in our study. Pregnant women suspected of PE and who underwent computed tomographic pulmonary angiography examination were included in the study. The least absolute shrinkage and selection operator regression technique was used to select the best prediction features, and multivariate logistic regression is used to build the prediction model. Bootstrap resampling 1000 times was used to validate the model visualized by nomogram. Evaluate the performance of the model from three aspects: identification, calibration and clinical utility. Results: Our predictive model indicated that chest tightness, anhelation, lactate, and D-dimer were associated with PE. The area under the receiver operating characteristic curve of the model was 0.836 (95% CI: [0.770-0.902]), indicating that our model had a good differential diagnostic performance. Good consistency between prediction and real observation was presented as the calibration curve. Decision curve analysis indicated that our model had a good net clinical benefit. Conclusions: We developed a novel numerical model for selecting risk factors for PE in pregnant and postpartum women. Our results may help obstetricians and gynaecologists to develop individualized treatment plans and PE prevention strategies.

Extracellular traps and the role in thrombosis

Thrombotic complications pose serious health risks worldwide. A significant change in our understanding of the pathophysiology of thrombosis has occurred since the discovery of extracellular traps (ETs) and their prothrombotic properties. As a result of immune cells decondensing chromatin into extracellular fibers, ETs promote thrombus formation by acting as a scaffold that activates platelets and coagulates them. The involvement of ETs in thrombosis has been reported in various thrombotic conditions including deep vein thrombosis (DVT), pulmonary emboli, acute myocardial infarction, aucte ischemic stroke, and abdominal aortic aneurysms. This review summarizes the existing evidence of ETs in human and animal model thrombi. The authors described studies showing the existence of ETs in venous or arterial thrombi. In addition, we studied potential novel therapeutic opportunities related to the resolution or prevention of thrombosis by targeting ETs.

Prognostic role of elevated lactate in acute pulmonary embolism: A systematic review and meta-analysis

BACKGROUND

Previous studies have shown elevated lactate was a good predictor for the prognosis of pulmonary embolism (PE). However, due to low number of patients and different expression of blood lactate in separate study, these results are inconsistent. Therefore, the aim of this meta-analysis is to evaluate the relationship between increased lactate levels and adverse outcome in acute PE.

METHOD

The literatures search was conducted in PubMed, Web of Science, and EMBASE until May 29, 2021.

RESULTS

Finally, 6 studies with 1706 patients were included in our meta-analysis. High lactate levels were markedly associated with overall mortality both in unselected PE patients (OR 5.13, 95% CI: 3.36-7.86, p < .00,001) and normotensive PE patients (OR 4.54, 95% CI: 2.64-7.80, p < .00,001), and PE-related short-term mortality in patients with elevated lactate was significantly higher than that in patients with normal levels (OR 9.05, 95% CI :4.08-20.10, p < .00,001). The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of lactate for predicting overall mortality in patients with acute PE were 0.67 (95% CI: 0.43-0.85), 0.73 (95% CI: 0.60-0.83), 2.5 (95% CI: 2.0-3.1), and 0.45 (95% CI: 0.26-0.78), respectively. The area under SROC curve (AUC) was 0.76 (95% CI: 0.73-0.80).

CONCLUSION

The result of our meta-analysis indicate that elevated blood lactate is a good predictor for overall mortality and short-term mortality in patients with acute PE, and can be routinely measured in risk stratification, but its prognostic role in patients with different risk classes still need to be verified.

Characteristics and outcomes of cancer patients who develop pulmonary embolism: A cross‑sectional study

Pulmonary embolism (PE), along with deep vein thrombosis, are collectively known as venous thromboembolism (VTE). Predisposing factors for PE include post-operative conditions, pregnancy, cancer and an advanced age; of note, a number of genetic mutations have been found to be associated with an increased risk of PE. The association between cancer and VTE is well-established, and cancer patients present a higher risk of a thrombotic event compared to the general population. In addition, PE is a significant cause of morbidity and mortality among cancer patients. The aim of the present study was to illustrate the clinical characteristics, laboratory findings, radiology features and outcomes of cancer patients who developed PE, collected from an anticancer hospital. For this purpose, adult cancer patients diagnosed with PE by imaging with computed tomography pulmonary angiography were enrolled. The following data were recorded: Demographics, comorbidities, type of cancer, time interval between cancer diagnosis and PE occurrence, the type of therapy received and the presence of metastases, clinical signs and symptoms, predisposing factors for PE development, laboratory data, radiological findings, electrocardiography findings, and the type of therapy received for PE and outcomes in a follow-up period of 6 months. In total, 60 cancer patients were enrolled. The majority of the cancer patients were males. The most common type of cancer observed was lung cancer. The majority of cases of PE occurred within the first year from the time of cancer diagnosis, while the majority of patients had already developed metastases. In addition, the majority of cancer patients had received chemotherapy over the past month, while they were not receiving anticoagulants and had central obstruction. A large proportion of patients had asymptomatic PE. The in-hospital mortality rate was 13.3% and no relapse or mortality were observed during the follow-up period. The present study demonstrates that elevated levels of lactic acid and an increased platelet count, as well as low serum levels of carcinoembryonic antigen, albumin and D-dimer, may be potential biomarkers for asymptomatic PE among cancer patients.

Cardiovascular Dysfunction in COVID-19: Association Between Endothelial Cell Injury and Lactate

Coronavirus disease 2019 (COVID-19), an infectious respiratory disease propagated by a new virus known as Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), has resulted in global healthcare crises. Emerging evidence from patients with COVID-19 suggests that endothelial cell damage plays a central role in COVID-19 pathogenesis and could be a major contributor to the severity and mortality of COVID-19. Like other infectious diseases, the pathogenesis of COVID-19 is closely associated with metabolic processes. Lactate, a potential biomarker in COVID-19, has recently been shown to mediate endothelial barrier dysfunction. In this review, we provide an overview of cardiovascular injuries and metabolic alterations caused by SARS-CoV-2 infection. We also propose that lactate plays a potential role in COVID-19-driven endothelial cell injury.

The Emerging Role of Neutrophil Extracellular Traps in Arterial, Venous and Cancer-Associated Thrombosis

Neutrophils play a vital role in the formation of arterial, venous and cancer-related thrombosis. Recent studies have shown that in a process known as NETosis, neutrophils release proteins and enzymes complexed to DNA fibers, collectively called neutrophil extracellular traps (NETs). Although NETs were originally described as a way for the host to capture and kill bacteria, current knowledge indicates that NETs also play an important role in thrombosis. According to recent studies, the destruction of vascular microenvironmental homeostasis and excessive NET formation lead to pathological thrombosis. In vitro experiments have found that NETs provide skeletal support for platelets, red blood cells and procoagulant molecules to promote thrombosis. The protein components contained in NETs activate the endogenous coagulation pathway to promote thrombosis. Therefore, NETs play an important role in the formation of arterial thrombosis, venous thrombosis and cancer-related thrombosis. This review will systematically summarize and explain the study of NETs in thrombosis in animal models and in vivo experiments to provide new targets for thrombosis prevention and treatment.

The Role of Acidosis in the Pathogenesis of Severe Forms of COVID-19

Simple Summary

Recently, several studies have shown that acidosis, which is increased acidity in the blood and other body tissues, is often associated with severe COVID-19. In this article, we look at the mechanisms and consequences of acidosis that can lead to an exacerbation of COVID-19. We want to draw the attention of readers to the threshold values of such disease characteristics as hypoxia and acidosis, which are associated with a sharp deterioration in the patient’s condition. Hypoxia and acidosis mutually reinforce each other according to the principle of a vicious cycle (that is, they are involved in a system of positive feedbacks). Elevated blood lactate (lactic acid) levels are associated with poor clinical outcomes in COVID patients. As a practical recommendation, we propose to pay more attention to the prevention of acidosis, including in the early stages of the disease, when the adjustment of homeostasis requires less effort and is less risky.

Abstract

COVID-19 has specific characteristics that distinguish this disease from many other infections. We suggest that the pathogenesis of severe forms of COVID-19 can be associated with acidosis. This review article discusses several mechanisms potentially linking the damaging effects of COVID-19 with acidosis and shows the existence of a vicious cycle between the development of hypoxia and acidosis in COVID-19 patients. At the early stages of the disease, inflammation, difficulty in gas exchange in the lungs and thrombosis collectively contribute to the onset of acidosis. In accordance with the Verigo-Bohr effect, a decrease in blood pH leads to a decrease in oxygen saturation, which contributes to the exacerbation of acidosis and results in a deterioration of the patient’s condition. A decrease in pH can also cause conformational changes in the S-protein of the virus and thus lead to a decrease in the affinity and avidity of protective antibodies. Hypoxia and acidosis lead to dysregulation of the immune system and multidirectional pro- and anti-inflammatory reactions, resulting in the development of a “cytokine storm”. In this review, we highlight the potential importance of supporting normal blood pH as an approach to COVID-19 therapy.

Fibrinolysis in Platelet Thrombi

The extent and duration of occlusive thrombus formation following an arterial atherothrombotic plaque disruption may be determined by the effectiveness of endogenous fibrinolysis. The determinants of endogenous fibrinolysis are the subject of much research, and it is now broadly accepted that clot composition as well as the environment in which the thrombus was formed play a significant role. Thrombi with a high platelet content demonstrate significant resistance to fibrinolysis, and this may be attributable to an augmented ability for thrombin generation and the release of fibrinolysis inhibitors, resulting in a fibrin-dense, stable thrombus. Additional platelet activators may augment thrombin generation further, and in the case of coronary stenosis, high shear has been shown to strengthen the attachment of the thrombus to the vessel wall. Neutrophil extracellular traps contribute to fibrinolysis resistance. Additionally, platelet-mediated clot retraction, release of Factor XIII and resultant crosslinking with fibrinolysis inhibitors impart structural stability to the thrombus against dislodgment by flow. Further work is needed in this rapidly evolving field, and efforts to mimic the pathophysiological environment in vitro are essential to further elucidate the mechanism of fibrinolysis resistance and in providing models to assess the effects of pharmacotherapy.

Fibrinolysis in Venous Thromboembolism

Fibrinolysis is of paramount importance in maintaining or regaining the patency of veins and pulmonary arteries obstructed by thrombi. Growing experimental and clinical evidence indicates that impaired fibrinolysis mediated by multiple complex mechanisms is involved in venous thromboembolism (VTE). Global plasma fibrin clot lysis markers, especially clot lysis time, have been reported to predict recurrent deep-vein thrombosis and pulmonary embolism. The current overview summarizes available data linking fibrinolysis to VTE and its long-term sequelae.

Right ventricular echocardiographic parameters associated with prothrombotic abnormalities in normotensive patients with acute pulmonary embolism

BACKGROUND

In acute pulmonary embolism (PE) right ventricular (RV) pressure overload negatively affects prognosis. Recently we have shown that RV dilatation is associated with a prothrombotic state in PE. We investigated which RV echocardiographic parameters best indicate prothrombotic alterations in acute PE.

METHODS

In 121 normotensive, noncancer PE patients, markers of RV dilatation and dysfunction were evaluated on admission using transthoracic echocardiography, along with prothrombotic state markers, i.e. increased endogenous thrombin generation (ETP), low fibrin clot permeability (K_s, a measure of clot density), and prolonged clot lysis time (CLT).

RESULTS

RV parasternal long axis (RVOT PLAX) >30 mm was associated with ETP (OR 3.86; 95% CI 1.55-9.62; p = 0.004) and CLT (OR 4.08; 95% CI 1.58-10.54; p = 0.004) in the top quartiles, but not with K_s. RV short parasternal axis (RVOT PSAX) >27 mm showed similar associations with higher ETP (OR 3.54; 95% CI 1.50-8.37; p = 0.004) and prolonged CLT (OR 2.78; 95% CI 1.17-6.62; p = 0.021). RV basal diameter >41 mm solely predicted prolonged CLT (OR 2.93; 95% CI 1.23-6.99; p = 0.016). The right atrium area, pulmonary trunk diameter, and tricuspid regurgitation maximum velocity were not related to prothrombotic markers, except for tricuspid annular plane systolic excursion weakly associated with ETP. Multivariable analysis showed that RVOT PSAX is independently associated with prolonged CLT (OR 1.16; 95% CI 1.04-1.30; p = 0.007), low K_s (OR 1.21; 95% CI 1.02-1.44; p = 0.029), and higher ETP (OR 1.14; 95% CI 1.03-1.26; p = 0.009).

CONCLUSIONS

Among RV echocardiographic parameters, the RVOT dilatation measured in PSAX best predicts prothrombotic alterations in PE patients.

Factor XIII and Fibrin Clot Properties in Acute Venous Thromboembolism

Coagulation factor XIII (FXIII) is converted by thrombin into its active form, FXIIIa, which crosslinks fibrin fibers, rendering clots more stable and resistant to degradation. FXIII affects fibrin clot structure and function leading to a more prothrombotic phenotype with denser networks, characterizing patients at risk of venous thromboembolism (VTE). Mechanisms regulating FXIII activation and its impact on fibrin structure in patients with acute VTE encompassing pulmonary embolism (PE) or deep vein thrombosis (DVT) are poorly elucidated. Reduced circulating FXIII levels in acute PE were reported over 20 years ago. Similar observations indicating decreased FXIII plasma activity and antigen levels have been made in acute PE and DVT with their subsequent increase after several weeks since the index event. Plasma fibrin clot proteome analysis confirms that clot-bound FXIII amounts associated with plasma FXIII activity are decreased in acute VTE. Reduced FXIII activity has been associated with impaired clot permeability and hypofibrinolysis in acute PE. The current review presents available studies on the role of FXIII in the modulation of fibrin clot properties during acute PE or DVT and following these events. Better understanding of FXIII’s involvement in the pathophysiology of acute VTE might help to improve current therapeutic strategies in patients with acute VTE.

Impact of intra-operative factors upon peri-operative outcomes in women undergoing hyperthermic intraperitoneal chemotherapy for gynecologic cancer

OBJECTIVES

To evaluate the incidence of intra-operative metabolic and electrolyte abnormalities and subsequent impact on peri-operative outcomes in women with gynecologic cancer undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS + HIPEC).

METHODS

An IRB-approved single institution retrospective cohort study was performed in women with gynecologic cancer who underwent CRS + HIPEC. Patient demographics, intra-operative electrolyte and metabolic values and peri-operative outcomes were recorded. To assess the association of pH and lactate upon post-operative outcomes, patients were divided in four quartiles for both variables and univariate analysis was performed.

RESULTS

100 consecutive women who underwent CRS + HIPEC from 2017 to 2020 were identified. Intra-operative blood transfusion and pressor support were required in 40% and 86%, respectively. The rate of ICU admission was 17%. Longer operative time (7.0 vs. 5.3 h, p = 0.002), increased blood loss (400.0 vs. 200.0 mL, p = 0.02) and transfusion (70.6% vs. 34.1%, p = 0.005) were associated with ICU admission. Compared to patients in the highest quartile of pH, lower median pH, (7.211 vs. 7.349, p < 0.001) was associated with increased rates of ICU admission, prolonged intubation (36.0% vs. 0.0%, p < 0.05, respectively) and any post-operative complication (72.0% vs. 28.0%, p = 0.01). Similarly, need for prolonged intubation (40% vs. 0%, p = 0.04) and VTE (13.0% vs. 0%, p = 0.01) were increased in women with the highest quartile of lactate levels compared to the lowest (4.7 vs 1.9, p < 0.001).

CONCLUSIONS

Intra-operative acidosis is associated with higher incidence of ICU admission and peri-operative complications following CRS + HIPEC in women with gynecologic cancer. These data support the importance of adequate intra-operative resuscitation and timely correction of hemodynamic and metabolic abnormalities.

Loose Fibrin Clot Structure and Increased Susceptibility to Lysis Characterize Patients with Central Acute Pulmonary Embolism: The Impact of Isolated Embolism

BACKGROUND

 Prothrombotic fibrin clot properties are associated with higher early mortality risk in acute pulmonary embolism (PE) patients. It is unknown whether different types of PE are associated with particular clot characteristics.

METHODS

 We assessed 126 normotensive, noncancer acute PE patients (median age: 59 [48-70] years; 52.4% males), who were categorized into central versus peripheral PE with or without concomitant deep vein thrombosis (DVT). Plasma fibrin clot permeability (K _s), clot lysis time (CLT), thrombin generation, platelet-derived markers, and fibrinolytic parameters were measured on admission. Plasma fibrin clot morphology was assessed by scanning electron microscopy (SEM).

RESULTS

 Patients with central PE (n = 76; 60.3%) compared with peripheral PE (n = 50; 39.7%) had 17.8% higher K _s and 14.3% shortened CLT (both p < 0.01 after adjustment for potential confounders including fibrinogen), with no differences between segmental and subsegmental PE. SEM analysis demonstrated larger fibrin fiber diameter and pore size in central PE compared with peripheral PE (both p < 0.01). For isolated PE, there was 23.3% higher K _s in central PE than in peripheral PE (n = 24; 19%) with no differences in other variables. Central PE combined with DVT (n = 45; 35.7%), as compared with central isolated PE (n = 31; 24.6%), was associated with shortened CLT (all p < 0.05).

CONCLUSION

 Our findings suggest that looser fibrin networks composed of thicker fibers with increased susceptibility to lysis characterize patients with central PE, suggesting that fibrin clot phenotype affects the size of thrombi occluding the pulmonary arteries, highlighting the role of fibrin structures in thrombus formation and stability.

Impaired Fibrinolysis in Patients with Isolated Aortic Stenosis is Associated with Enhanced Oxidative Stress

Aortic stenosis (AS) has been associated with impaired fibrinolysis and increased oxidative stress. This study aimed to investigate whether oxidative stress could alter fibrin clot properties in AS. We studied 173 non-diabetic patients, aged 51–79 years, with isolated AS. We measured plasma protein carbonylation (PC) and thiobarbituric acid reactive substances (TBARS), along with plasma clot permeability (K_s), thrombin generation, and fibrinolytic efficiency, which were evaluated by two assays: clot lysis time (CLT) and lysis time (Lys50). Coagulation factors and fibrinolytic proteins were also determined. Plasma PC showed an association with AS severity, reflected by the aortic valve area and the mean and maximum aortic gradients. Plasma PC was positively correlated with CLT, Lys50, plasminogen activator inhibitor-1 (PAI-1), and tissue factor (TF) antigens. TBARS were positively correlated with maximum aortic gradient, Lys50, and TF antigen. Regression analysis showed that PC predicted prolonged CLT (>104 min; odds ratio (OR) 6.41, 95% confidence interval (CI) 2.58–17.83, p < 0.001) and Lys50 (>565 s; OR 5.83, 95% CI 2.23–15.21, p < 0.001). Multivariate regression analysis showed that mean aortic gradient, PC, α2-antiplasmin, PAI-1, and triglycerides were predictors of prolonged CLT, while PC, α2-antiplasmin, and fibrinogen were predictors of Lys50. Our findings suggest that elevated oxidative stress contributes to impaired fibrinolysis in AS and is associated with AS severity.