Pulmonary Embolism Model Research Articles

Prognostic impact of the tricuspid annular plane systolic excursion/pulmonary arterial systolic pressure ratio in acute pulmonary embolism

Abstract Background Currently available risk stratification models for acute pulmonary embolism (PE) include hemodynamic status, cardiac biomarkers, right ventricle (RV) dysfunction on imaging, and clinical scores. Focusing on length-tension relationship of the ventricle might have a superior predictive capability over RV dysfunction in terms of mortality and classification of patients with acute PE. In this study, our hypothesis suggests that tricuspid annular plane systolic excursion (TAPSE)/systolic pulmonary artery pressure (sPAP) ratio has superior predictive capability for in-hospital mortality in patients with acute PE compared to TAPSE or sPAP as distinct measures. Methods This single-center study comprised retrospectively evaluated 703 patients referred to our tertiary cardiovascular center with acute PE. We divided patients into quartiles by TAPSE/sPAP ratio. Different models were developed to quantify the predictive relationship between in-hospital death and echocardiographic measurements. A base model was created with variables including risk status and RV/LV ratio >1. Then, to evaluate the predictive contribution of each measurement; TAPSE/sPAP, TAPSE, and sPAP were sequentially added to the base model. After that, the performance of each model was evaluated. Results Predictive and discriminative power was the highest in model containing TAPSE/sPAP. There was still a significant inverse association between TAPSE/sPAP and risk of in-hospital death even after adjusting by risk status and RV/LV ratio >1. ROC curve analysis for TAPSE/sPAP revealed the best cut-off value as 0.34. Conclusion The outcomes of our study reveals that the ratio of TAPSE/sPAP serves as a more potent predictor of mortality than either of the two measurements taken separately. The interpretation and utilization of the TAPSE/sPAP cut-off value in acute PE can assist in identifying patients at risk of deterioration and guide the consideration of more intensive treatment options across all risk groups.

Establishment of a Minimally Invasive Rat Model of Pulmonary Embolism Using Autologous Blood Clots

Establishment of a Minimally Invasive Rat Model of Pulmonary Embolism Using Autologous Blood Clots

NUPR1 modulates pulmonary embolism progression via smooth muscle cells phenotypic transformation

ObjectiveThis study aimed to investigate the role of Nuclear Protein 1 (NUPR1) in pulmonary embolism (PE) and its impact on the phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs). MethodsA PE model was established via autologous pulmonary emboli infusion into the jugular vein. Partial Pressure of Oxygen (PaO2), Oxygenation Index (OI), Brain Natriuretic Peptide (BNP), and Troponin I (TnI) were measured, and lung tissue was subjected to hematoxylin-eosin (HE) staining. NUPR1 expression was assessed through Immunofluorescence and Western blot analyses. To investigate role of NUPR1, PE rats were treated with lentiviral vectors for NUPR1 knockdown (si-NUPR1) or overexpression (ov-NUPR1), and the effects on lung pathology were examined. NUPR1 expression was evaluated in human PASMCs. Additionally, PASMCs from SD rats were cultured under normoxic and hypoxic conditions to evaluate NUPR1 expression. Transfection of NUPR1 expression vectors into PASMCs allowed monitoring of phenotypic transformation-associated protein changes and PASMCs activity. ResultsIncreased NURP1 was observed in human-derived PASMCs. In PE rats, histological examination revealed ruptured pulmonary alveoli, exudate accumulation, interstitial edema, and infiltration of inflammatory cells, concomitant with elevated NUPR1 expression levels. Knockdown of NUPR1 in PE rats significantly improved lung tissue structure, reducing alveolar rupture and interstitial edema. Conversely, NUPR1 overexpression exacerbated lung damage, leading to increased inflammatory infiltration. NUPR1 expression in rat PASMCs remained stable under normoxic conditions; however, under hypoxic conditions, NUPR1 protein expression increased progressively over time. Subsequent upregulation of NUPR1 expression led to a decrease in the levels of contractile phenotype markers α-SMA and SM22α in PASMCs, accompanied by increased expression of synthetic phenotype markers Vimentin and OPN. This phenotypic shift was associated with enhanced cellular proliferation, invasion, and migration. ConclusionsElevated NUPR1 expression in PE exacerbates abnormal PASMCs proliferation by promoting their phenotypic transformation, thereby fostering the pathological progression of PE.

Monotropein alleviates acute pulmonary embolism in rats by inhibiting the NF-κB pathway

Objective This study examines the therapeutic potential of monotropein (Mon) in a rat model of acute pulmonary embolism (APE), aiming to elucidate its mechanistic role and provide new insights for APE treatment. Methods: Thirty Sprague Dawley (SD) rats were randomly assigned to five groups (n = 6 per group): sham, Mon (40 mg/kg), APE, APE + 20 mg/kg Mon, and APE + 40 mg/kg Mon. APE was induced via autologous thrombus infusion in all groups except sham and Mon-only groups. We assessed blood gas parameters, lung wet/dry weight (W/D) ratio, and oxidative stress markers. Additionally, excised lung tissues underwent evaluation for serum inflammatory factors via ELISA, apoptotic cells via TUNEL assay, and protein expression via Western blot. Results: Compared to the sham group, APE-induced rats exhibited significantly elevated blood oxygen levels and increased pro-inflammatory factors, including interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-8. Mon treatment effectively mitigated these APE-induced changes, reducing blood oxygen concentration and downregulating IL-1β and TNF-α levels. Furthermore, Mon demonstrated anti-apoptotic effects by decreasing cleaved caspase-3 and Bax protein levels while upregulating Bcl-2 expression. Mon also suppressed nuclear factor-κB (NF-κB) activation by inhibiting the phosphorylation levels of p65/RelA and IκBα proteins, while the total protein level of IκBα was increased with Mon treatment. Conclusion: Mon effectively ameliorated lung tissue injury in APE rats by inhibiting apoptosis, attenuating inflammatory responses, and alleviating oxidative stress. These beneficial effects appear to be mediated through modulation of the NF-κB pathway, suggesting Mon as a promising therapeutic candidate for APE treatment.

A prognostic prediction model for acute pulmonary embolism.

Acute pulmonary embolism (APE) is a very common and important medical emergency in intensive care units with an unfavorable prognosis. This study aims to explore the prognostic factors of APE and to construct a prognostic prediction model. A retrospective analysis was conducted on 252 APE patients in the emergency department of our hospital from January 2020 to March 2024. The initial observation endpoint was set as the mortality status of patients within 30 days of admission. Cox multivariate regression analysis was used to identify independent risk factors for prognosis. Based on these factors, a nomogram predictive model was constructed and evaluated using R software. Within 30 days of admission, 42 patients died with an overall mortality rate of 16.6% (42/252). Binary Cox multivariate regression analysis indicated that age ≥ 62.5 (HR: 2.64, 95% CI: 1.23-5.63, p = 0.012), right ventricular dysfunction (RVD) (HR: 4.58, 95% CI: 1.76-11.96, p = 0.002), white blood cell count (WBC) ≥ 13.1 (HR: 2.35, 95% CI: 1.20-4.60, p = 0.013), albumin/fibrinogen ratio (AFR) < 9.15 (HR: 3.36, 95% CI: 1.76-6.42, p < 0.001), Prognostic Nutritional Index (PNI) < 50.3 (HR: 4.35, 95% CI: 1.62-11.71, p = 0.004), and Systemic Inflammation Response Index (SIRI) ≥ 1.05 (HR: 7.21, 95% CI: 3.38-15.37,p < 0.001) were independent risk factors for mortality. The nomogram model based on these factors demonstrated a good predictive value for 30-day mortality, with an AUC of 0.908. The nomogram model based on age, RVD, WBC, AFR, PNI, and SIRI has a well prognostic value for APE patients.

G protein–coupled receptor kinase 5 regulates thrombin signaling in platelets

BackgroundOur prior genome-wide association study of thrombin-induced platelet aggregation identified a G protein–coupled receptor kinase 5 (GRK5) noncoding variant (rs10886430-G) that is strongly associated with increased platelet reactivity to thrombin. This variant predisposes to increased risk of stroke, pulmonary embolism, and venous thromboembolism. ObjectivesTo determine role of platelet specific GRK5 in platelet responses to agonists and injury. MethodsPlatelets from GRK5 mutant mice have been shown to have increased thrombin sensitivity, indicating that GRK5 may be a negative regulator of platelet activation. However, this has not been studied in a platelet-specific manner. We therefore used platelet-specific GRK5 mutant mice and models of thrombosis and pulmonary embolism. ResultsWe now demonstrate that mice lacking GRK5 specifically in platelets had a mild increase in thrombin responses in vitro and a shortened time to arterial thrombosis in vivo. In addition, platelet GRK5 mutant mice had increased thrombin but not collagen-induced thrombus burden in a mouse model of pulmonary embolism. ConclusionThese data indicate that platelet GRK5 has a significant role in limiting platelet responses to thrombin.

Construction and validation of risk prediction models for pulmonary embolism in hospitalized patients based on different machine learning methods.

This study aims to apply different machine learning (ML) methods to construct risk prediction models for pulmonary embolism (PE) in hospitalized patients, and to evaluate and compare the predictive efficacy and clinical benefit of each model. We conducted a retrospective study involving 332 participants (172 PE positive cases and 160 PE negative cases) recruited from Guangdong Medical University. Participants were randomly divided into a training group (70%) and a validation group (30%). Baseline data were analyzed using univariate analysis, and potential independent risk factors associated with PE were further identified through univariate and multivariate logistic regression analysis. Six ML models, namely Logistic Regression (LR), Decision Tree (DT), Random Forest (RF), Naive Bayes (NB), Support Vector Machine (SVM), and AdaBoost were developed. The predictive efficacy of each model was compared using the receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC). Clinical benefit was assessed using decision curve analysis (DCA). Logistic regression analysis identified lower extremity deep venous thrombosis, elevated D-dimer, shortened activated partial prothrombin time, and increased red blood cell distribution width as potential independent risk factors for PE. Among the six ML models, the RF model achieved the highest AUC of 0.778. Additionally, DCA consistently indicated that the RF model offered the greatest clinical benefit. This study developed six ML models, with the RF model exhibiting the highest predictive efficacy and clinical benefit in the identification and prediction of PE occurrence in hospitalized patients.

Phillyrin and its metabolites treat pulmonary embolism by targeting PLCβ3 to inhibit platelet activation

Ethnopharmacological relevanceLian Qiao (LQ), the dried fruit of Forsythia suspensa (Thunb.) Vahl, is a well-documented traditional Chinese medicine known for its detoxifying and heat-clearing properties. Clinically, compounds containing LQ are widely used to treat thrombotic diseases, indicating that it may have antithrombotic effects. However, its exact mechanism of action remains unknown. Aim of the studyThis study aimed to verify the antithrombotic effect of LQ and further explore the material basis and target mechanism of its antithrombotic effect using various biological methods. Materials and methodsAn epinephrine-collagen-thrombin-induced mouse model of acute pulmonary embolism (APE) was established to study the effects of LQ on thrombus development. A UPLC/Q/TOF-MS screening and identification system based on the inhibition of platelet aggregation and Ca2+ antagonism was established to determine the pharmacodynamic components of LQ that inhibit platelet activation. The inhibitory effect of active ingredients on platelet activation, and the determination of the target of their inhibitory effect on platelet activation have been studied using chemical proteomics. Furthermore, based on the structure and function of the target protein, a multidisciplinary approach was adopted to analyze the molecular mechanism of active ingredient binding to target proteins and to evaluate the effects of active ingredients on the downstream signaling pathways of target proteins. ResultsLQ showed significant anticoagulant effects in APE model mice. Phillyrin and phillygenin were the antiplatelet-activating components of LQ. PLCβ3 was identified as a target for inhibiting platelet activation by phillyrin and its metabolites. The mechanism underlying the effect involves phillyrin and its metabolites inhibiting PLCβ3 activity by blocking the binding of PLCβ3 to Gαq through non-covalently targeting the ASN260 of PLCβ3, thus inhibiting the downstream Gαq-PLCβ3-Ca2+ signaling pathway, effectively hindering platelet activation and therefore playing an anticoagulant role. ConclusionThis study not only proposes and validates the antithrombotic effect of LQ for the first time but also finds that phillyrin and phillygenin are the main pharmacological substances through which LQ exerts antithrombotic activity and reveals a novel mechanism by which they exert antiplatelet activity by directly targeting and inhibiting PLCβ3 activity. These findings significantly contribute to our understanding of the therapeutic potential of phillyrin and provide important clues for the discovery and development of new antiplatelet drugs.

Validation of a pulmonary embolism risk assessment model in gynecological inpatients

ObjectiveTo compare the predictive efficacy of the PADUA and Caprini models for pulmonary embolism (PE) in gynecological inpatients, analyze the risk factors for PE, and validate whether both models can effectively predict mortality rates.MethodsA total of 355 gynecological inpatients who underwent computed tomography pulmonary angiography (CTPA) were included in the retrospective analysis. The comparative assessment of the predictive capabilities for PE between the PADUA and Caprini was carried out using receiver operating characteristic (ROC) curves. Logistic regression analysis was used to identify risk factors associated with PE. Additionally, Kaplan–Meier survival analysis plots were generated to validate the predictive efficacy for mortality rates.ResultsAmong 355 patients, the PADUA and Caprini demonstrated the area under the curve (AUC) values of 0.757 and 0.756, respectively. There was no statistically significant difference in the AUC between the two models (P = 0.9542). Multivariate logistic analysis revealed immobility (P < 0.001), history of venous thromboembolism (VTE) (P = 0.002), thrombophilia (P < 0.001), hormonal treatment (P = 0.022), and obesity (P = 0.019) as independent risk factors for PE. Kaplan–Meier survival analysis demonstrated the reliable predictive efficacy of both the Caprini (P = 0.00051) and PADUA (P = 0.00031) for mortality. ROC for the three- and six-month follow-ups suggested that the Caprini model exhibited superior predictive efficacy for mortality.ConclusionsThe PADUA model can serve as a simple and effective tool for stratifying high-risk gynecological inpatients before undergoing CTPA. The Caprini model demonstrated superior predictive efficacy for mortality rates.

Immediate cardiopulmonary responses to consecutive pulmonary embolism: a randomized, controlled, experimental study

BackgroundAcute pulmonary embolism (PE) induces ventilation-perfusion mismatch and hypoxia and increases pulmonary pressure and right ventricular (RV) afterload, entailing potentially fatal RV failure within a short timeframe. Cardiopulmonary factors may respond differently to increased clot burden. We aimed to elucidate immediate cardiopulmonary responses during successive PE episodes in a porcine model.MethodsThis was a randomized, controlled, blinded study of repeated measurements. Twelve pigs were randomly assigned to receive sham procedures or consecutive PEs every 15 min until doubling of mean pulmonary pressure. Cardiopulmonary assessments were conducted at 1, 2, 5, and 13 min after each PE using pressure-volume loops, invasive pressures, and arterial and mixed venous blood gas analyses. ANOVA and mixed-model statistical analyses were applied.ResultsPulmonary pressures increased after the initial PE administration (p < 0.0001), with a higher pulmonary pressure change compared to pressure change observed after the following PEs. Conversely, RV arterial elastance and pulmonary vascular resistance was not increased after the first PE, but after three PEs an increase was observed (p = 0.0103 and p = 0.0015, respectively). RV dilatation occurred following initial PEs, while RV ejection fraction declined after the third PE (p = 0.004). RV coupling exhibited a decreasing trend from the first PE (p = 0.095), despite increased mechanical work (p = 0.003). Ventilatory variables displayed more incremental changes with successive PEs.ConclusionIn an experimental model of consecutive PE, RV afterload elevation and dysfunction manifested after the third PE, in contrast to pulmonary pressure that increased after the first PE. Ventilatory variables exhibited a more direct association with clot burden.

Abstract 1073: Longitudinal Imaging Of NF-kappaB In Murine Pulmonary Embolism

Objective: Pulmonary embolism (PE) is a common condition that urgently needs novel diagnostic and therapeutic strategies. Here, we investigated PE-induced inflammation via longitudinal imaging of transcription factor NF-kappaB (NFkB) activation signals in murine PE. Understanding the temporal activation of inflammatory mediators, such as NFkB, in PE may lead to future medical interventions or better patient stratification. Methods: NFkB activation was assessed using male, 12-16w old, NFkB-GFP-luciferase (NGL) reporter mice (n=20 PE animals). Stasis venous thrombosis (VT) was induced in the femoral veins of donor mice on day 0. On day 1, the thrombus was resected and intravenously injected into recipient mice to create the PE model. PE animals underwent bioluminescence imaging on days -1, 1, 4, and 7. Regions-of-interest (ROI) areas were kept constant and placed over areas of PE as verified in other modalities. Lung and PE morphometrics were imaged by fluorescence-mediated tomography and computed tomography using a fibrin-specific molecular imaging agent, FTP11 (i.v. 150nmol/kg). Cardiac function pre- and post-PE was assessed by ultrasound and pulmonary arterial pressure measurements. Mouse cohorts were sacrificed 1, 4, and 7 days following stasis-VT embolization and underwent histological analysis of the PE. Results: The mean volume of the femoral stasis-VT was 1.21±0.25 mm 3 . The bioluminescence signal plateau was found at 4-8 minutes post-intravenous injection of D-luciferin in PE animals. The six-minute post-injection image was utilized in comparing longitudinal images. Bioluminescence from the activation of NFkB in the PE ROI showed a maximal signal in the day 1 PE with a 55.0% (334 to 151RU) decrease in signal from day 1 to day 7(p&lt;0.05). Histological and protein assays validated the activation and localization of NFkB. In PE animals, immunohistochemistry of infiltrating CD45-positive cells showed increased cell numbers from day 1 to day 7 (p&lt;0.05). Since PE is confided spatially to a lung lobe, contralateral PE-negative lobes also showed increased infiltrating cells compared to sham animals. Conclusions: Quantitative serial imaging pre- and post-PE demonstrates an inflammatory timeline in PE-induced NFkB activation.

Thrombosis risk prediction in lymphoma patients: A multi-institutional, retrospective model development and validation study.

Venous thromboembolism (VTE) poses a significant risk to cancer patients receiving systemic therapy. The generalizability of pan-cancer models to lymphomas is limited. Currently, there are no reliable risk prediction models for thrombosis in patients with lymphoma. Our objective was to create a risk assessment model (RAM) specifically for lymphomas. We performed a retrospective cohort study to develop Fine and Gray sub-distribution hazard model for VTE and pulmonary embolism (PE)/ lower extremity deep vein thrombosis (LE-DVT) respectively in adult lymphoma patients from the Veterans Affairs national healthcare system (VA). External validations were performed at the Harris Health System (HHS) and the MD Anderson Cancer Center (MDACC). Time-dependent c-statistic and calibration curves were used to assess discrimination and fit. There were 10,313 (VA), 854 (HHS), and 1858 (MDACC) patients in the derivation and validation cohorts with diverse baseline. At 6 months, the VTE incidence was 5.8% (VA), 8.2% (HHS), and 8.8% (MDACC), respectively. The corresponding estimates for PE/LE-DVT were 3.9% (VA), 4.5% (HHS), and 3.7% (MDACC), respectively. The variables in the final RAM included lymphoma histology, body mass index, therapy type, recent hospitalization, history of VTE, history of paralysis/immobilization, and time to treatment initiation. The RAM had c-statistics of 0.68 in the derivation and 0.69 and 0.72 in the two external validation cohorts. The two models achieved a clear differentiation in risk stratification in each cohort. Our findings suggest that easy-to-implement, clinical-based model could be used to predict personalized VTE risk for lymphoma patients.

Changes and significance of the fibrinolytic system following two pulmonary thromboembolisms in a rabbit model.

In this study, we examined the changes in the fibrinolytic system in a rabbit model of two acute pulmonary thromboembolisms (PTE). Fourteen healthy adult New Zealand white rabbits were divided into three groups: the single PTE group (five rabbits), the double PTE group (five rabbits), and the control group (four rabbits). A rabbit model of acute pulmonary embolism was established, and immunohistochemistry and polymerase chain reaction (PCR) were performed on tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) in plasma, and pulmonary embolism tissue. Plasma results: 1) t-PA levels: one hour following the initial modeling, the levels of t-PA in the modeling groups were significantly lower than those in the control group (P<0.05). In addition, the t-PA levels in the double PTE group were found to be lower after the modeling, as compared to the pre-modeling period (P<0.05). One hour after the second modeling, the double PTE group had lower t-PA levels compared to the control group (P<0.05). However, t-PA rebounded two hours after modeling in the double PTE group. One week after the second modeling, the double PTE group had higher t-PA levels compared to the other two groups (P<0.05). 2) PAI-1 results: one hour after the initial modeling, PAI-1 levels in the two modeling groups were lower compared to the pre-modeling period and control groups (P<0.05). Two hours following modeling, PAI-1 levels in both modeling groups were lower compared to the control group (P<0.05). PAI-1 levels were lower in the double PTE group one and two hours after the second modeling compared to the other two groups and pre-modeling period (P<0.05). 3) The immunohistochemistry results: the expression of PAI-1 decreased in the two modeling groups, while t-PA expression increased compared to the control group. 4) PCR results: t-PA mRNA expression did not differ among the three groups. The PAI-1 mRNA expression was lower in the two PTE groups compared to the control group. We conclude that in the early stages of PTE, the local fibrinolytic activity of the thrombus is increased, which is favorable for thrombolysis. However, as the thrombus persists, the activity of the fibrinolytic system is inhibited, contributing to the development of chronic thromboembolic pulmonary hypertension.

Preferential vasodilator effects of levosimendan in resistance pulmonary arteries in a rodent pulmonary embolism model

Background: We compared the vasoactive effects of levosimendan on isolated conduit pulmonary arteries (CPA) and resistance pulmonary arteries (RPA) versus mesenteric arteries, and we assessed the pulmonary artery (PA) vascular function and the PA vasoactive effects of levosimendan in a rodent pulmonary embolism (PE) model.Methods: One group of male Wistar rats (200-300 g) was killed by decapitation to obtain pulmonary and mesenteric rings. Another group was assigned to a massive PE or saline solution infusion. After euthanasia, mesenteric arteries and CPA (1-2 mm) and RPA (≤0.5 mm) were dissected and cut into 2-3 mm wide rings, recording contractile tension. We obtained the concentration-response curves of cumulative doses of levosimendan on pre-contracted arterial rings from decapitated and sham/embolized animals. A set of RPA rings was exposed to acute hypoxia. The effect of PE on the pulmonary vasoactive function was assessed by dose-response curves of acetylcholine (ACh) and endothelin-1 (ET-1) of PA rings from sham/embolized animals.Results: Levosimendan relaxant potency of RPA was similar to that of mesenteric arteries and higher than CPA, while mesenteric rings showed the maximal relaxant effect, followed by RPA and CPA, respectively. PE did not affect the vasoactive response of PA rings either to ACh or to ET-1, and the relaxant effects of CPA and RPA to levosimendan were also preserved. Acute hypoxia reduced (p&lt;0.05) but did not avoid the RPA relaxant effect of levosimendan.Conclusions: Levosimendan is a more specific vasodilator of RPA with a similar relaxant potency as mesenteric arteries, which is preserved after PE but significantly reduced during hypoxia.

Development and validation of a novel model to predict pulmonary embolism in cardiology suspected patients: A 10-year retrospective analysis.

As there are no predictive models for pulmonary embolism (PE) in patients with suspected PE at cardiology department. This study developed a predictive model for the probability of PE development in these patients. This retrospective analysis evaluated data from 995 patients with suspected PE at the cardiology department from January 2012 to December 2021. Patients were randomly divided into the training and validation cohorts (7:3 ratio). Using least absolute shrinkage and selection operator regression, optimal predictive features were selected, and the model was established using multivariate logistic regression. The features used in the final model included clinical and laboratory factors. A nomogram was developed, and its performance was assessed and validated by discrimination, calibration, and clinical utility. Our predictive model showed that six PE-associated variables (age, pulse, systolic pressure, syncope, D-dimer, and coronary heart disease). The area under the curve - receiver operating characteristic curves of the model were 0.721 and 0.709 (95% confidence interval: 0.676-0.766 and 0.633-0.784), respectively, in both cohorts. We also found good consistency between the predictions and real observations in both cohorts. In decision curve analysis, the numerical model had a good net clinical benefit. This novel model can predict the probability of PE development in patients with suspected PE at cardiology department.

An intelligent DNA nanodevice for precision thrombolysis.

Thrombosis is a leading global cause of death, in part due to the low efficacy of thrombolytic therapy. Here, we describe a method for precise delivery and accurate dosing of tissue plasminogen activator (tPA) using an intelligent DNA nanodevice. We use DNA origami to integrate DNA nanosheets with predesigned tPA binding sites and thrombin-responsive DNA fasteners. The fastener is an interlocking DNA triplex structure that acts as a thrombin recognizer, threshold controller and opening switch. When loaded with tPA and intravenously administrated in vivo, these DNA nanodevices rapidly target the site of thrombosis, track the circulating microemboli and expose the active tPA only when the concentration of thrombin exceeds a threshold. We demonstrate their improved therapeutic efficacy in ischaemic stroke and pulmonary embolism models, supporting the potential of these nanodevices to provide accurate tPA dosing for the treatment of different thromboses.

Prognostic Impact of the Tricuspid Annular Plane Systolic Excursion/Pulmonary Arterial Systolic Pressure Ratio in Acute Pulmonary Embolism.

Currently available risk stratification models for acute pulmonary embolism (PE) include hemodynamic status, cardiac biomarkers, right ventricle (RV) dysfunction on imaging, and clinical scores. Focusing on the length-tension relationship of the ventricle might have a superior predictive capability over RV dysfunction in terms of mortality and classification of patients with acute PE. In this study, our hypothesis suggests that the tricuspid annular plane systolic excursion (TAPSE)/systolic pulmonary artery pressure (sPAP) ratio has superior predictive capability for in-hospital mortality in patients with acute PE compared to TAPSE or sPAP as distinct measures. This single-center study comprised retrospectively evaluated 703 patients referred to our tertiary cardiovascular center with acute PE. We divided patients into quartiles based on the TAPSE/sPAP ratio. Different models were developed to quantify the predictive relationship between in-hospital death and echocardiographic measurements. A base model was created with variables including risk status and RV/LV ratio >1. Then, to evaluate the predictive contribution of each measurement; TAPSE/sPAP, TAPSE, and sPAP were sequentially added to the base model. After that, the performance of each model was evaluated. Predictive and discriminative power was the highest in model containing TAPSE/sPAP. There was still a significant inverse association between TAPSE/sPAP and the risk of in-hospital death even after adjusting for risk status and RV/LV ratio >1. Receiver operating characteristic curve analysis for TAPSE/sPAP revealed the best cut-off value as 0.34. The outcomes of our study reveal that the ratio of TAPSE/sPAP serves as a more potent predictor of mortality than either of the 2 measurements taken separately. The interpretation and utilization of the TAPSE/sPAP cut-off value in acute PE can assist in identifying patients at risk of deterioration and guide the consideration of more intensive treatment options across all risk groups.

Establishment of machine learning-based tool for early detection of pulmonary embolism

Background and objectivesPulmonary embolism (PE) is a complex disease with high mortality and morbidity rate, leading to increasing society burden. However, current diagnosis is solely based on symptoms and laboratory data despite its complex pathology, which easily leads to misdiagnosis and missed diagnosis by inexperienced doctors. Especially, CT pulmonary angiography, the gold standard method, is not widely available. In this study, we aim to establish a rapid and accurate screening model for pulmonary embolism using machine learning technology. Importantly, data required for disease prediction are easily accessed, including routine laboratory data and medical record information of patients. MethodsWe extracted features from patients' routine laboratory results and medical records, including blood routine, biochemical group, blood coagulation routine and other test results, as well as symptoms and medical history information. Samples with a feature loss rate greater than 0.8 were deleted from the original database. Data from 4723 cases were retained, 231 of which were positive for pulmonary embolism. 50 features were retained through the positive and negative statistical hypothesis testing which was used to build the predictive model. In order to avoid identification as majority-class samples caused by the imbalance of sample proportion, we used the method of Synthetic Minority Oversampling Technique (SMOTE) to increase the amount of information on minority samples. Five typical machine learning algorithms were used to model the screening of pulmonary embolism, including Support Vector Machines, Logistic Regression, Random Forest, XGBoost, and Back Propagation Neural Networks. To evaluate model performance, sensitivity, specificity and AUC curve were analyzed as the main evaluation indicators. Furthermore, a baseline model was established using the characteristics of the pulmonary embolism guidelines as a comparison model. ResultsWe found that XGBoost showed better performance compared to other models, with the highest sensitivity and specificity (0.99 and 0.99, respectively). Moreover, it showed significant improvement in performance compared to the baseline model (sensitivity and specificity were 0.76 and 0.76 respectively). More important, our model showed low missed diagnosis rate (0.46) and high AUC value (0.992). Finally, the calculation time of our model is only about 0.05 s to obtain the possibility of pulmonary embolism. ConclusionsIn this study, five machine learning classification models were established to assess the likelihood of patients suffering from pulmonary embolism, and the XGBoost model most significantly improved the precision, sensitivity, and AUC for pulmonary embolism screening. Collectively, we have established an AI-based model to accurately predict pulmonary embolism at early stage.

The Actin Bundling Protein L-Plastin Mediates Platelet Force Generation and Thrombosis

Within minutes of activation, platelets dramatically change their shape, forming filopodia and lamellipodia, aggregate with other platelets or different cells, and can increase their surface area up to 4 times. This relies on a dynamic actin cytoskeleton, regulated by many actin binding proteins in a time- and spatial-specific manner. Deficiency or inhibition of several actin binding proteins in platelets have been shown with impaired platelet spreading and reduced thrombosis. Recently, we found that an actin bundling protein, L-plastin, is expressed in platelets. Its function in platelets has not been studied. In megakaryocytes, we showed that L-plastin is responsible for maintaining cytoskeletal stiffness; in this study we sought to determine L-plastin's role in platelet functions, including thrombosis. We examined the role of L-plastin in platelets in vivo and ex vivo using L-plastin deficient ( Lcp1 -/-) male and female mice. First, we used the collagen/epinephrine induced pulmonary embolism (PE) model and found that survival times were significantly shorter in Lcp1 -/- mice than in their littermate wildtype (WT) controls (Mean±SEM WT 202±12 sec, Lcp1 -/- 139.5±14 sec, P=0.004), suggesting accelerated thrombosis upon L-plastin deficiency in vivo. Second, we examined L-plastin's role in arterial thrombosis in vivo using the laser-induced cremaster arteriole thrombosis mode. Platelets were labeled with anti-GPIb IgG derivative X488 and the thrombosis formation after laser injury was recorded. Preliminary data indicate that thrombi in Lcp1 -/- mice are larger than those in WT mice. Third, we examined L-plastin's role in platelet adhesion using a microfluidics assay with DiOC6-labelled whole blood. At a shear rate of 200/s, the Lcp1 -/- mice had significantly increased platelet adhesion to both collagen and fibrinogen matrices. Fourth, to evaluate the effect of L-plastin on platelet aggregation in vitro, we stimulated washed platelets with 3 different concentrations of thrombin and measured the platelet aggregation (i.e., 0.1, 0.5 and 1 U/mL). When platelets are stimulated with 0.5U/mL or 1U/mL thrombin, platelets from WT and Lcp1 -/- mice showed comparable aggregation kinetics. At 0.1U/mL thrombin, however, preliminary data showed increased aggregation in the Lcp1 -/- group. The difference between the low and high concentration of thrombin indicates potential regulation of the GPIba mediated actin cytoskeleton rearrangement during platelet aggregation. We next examined under low thrombin concentration, the platelet actin cytoskeleton reorganization and platelet spreading. We seeded washed platelets on a fibrinogen matrix with the presence of thrombin (0.1U/mL). Platelets were then fixed and stained for F-actin and imaged using immunofluorescent confocal microscopy. The spreading area per platelet was calculated using FIJI software. Platelets from Lcp1 -/- mice showed significantly increased average membrane area at 30 min (Median WT 689 pixels, Lcp1 -/- 866 pixels, P&amp;lt;0.0001). This suggests that the actin rearrangement in platelets upon fibrinogen activation and thrombin stimulation is inhibited by L-plastin. Lastly, we examined whether L-plastin is involved in platelet force generation during the actin reorganization. We used a recently developed “black dot” assay. Briefly, a fluorescent pattern (i.e., black dots) was microcontact printed onto a flexible polydimethylsiloxane substrate and coated with fibrinogen. Platelets were seeded onto the matrix and fixed after 30 min. The contractile forces of individual platelets were measured based on the deformation of the fluorescent micropattern as illustrated in Fig 1A. The contractile force in platelets from Lcp1 -/- mice is decreased with altered actin distribution pattern compared to WT mice (Fig 1. Contractile force per platelet, Mean±SEM WT 14.78±0.86nN, Lcp1 -/- 12.03±0.67nN, P=0.01). In summary, we found accelerated thrombosis in Lcp1 -/- mice, associated with accelerated platelet adhesion and spreading ex vivo. Mechanistically, our preliminary data suggest this is due to impaired actin bundle formation and decreased platelet contractile force. L-plastin may be unique among actin binding proteins.

Pulmonary vasoconstriction plays a major role in the acute phase of pulmonary embolism in pigs

Abstract Background Pulmonary vascular resistance (PVR) increases in acute pulmonary embolism (PE) due to both mechanical obstruction and pulmonary vasoconstriction. Attenuation of adverse pulmonary vasoconstriction has shown promise as a treatment of acute PE in experimental studies. However, clinical trials have failed to replicate these beneficial effects in PE patients. Time may be a factor in this discrepancy between experimental and clinical studies. In experimental PE studies, PVR acutely increases and decreases within hours. Meanwhile in clinical trials, the time from symptom onset to study inclusion is often days, at which time PVR may already be decreased. Whether this decrease in PVR is due to reduced mechanical obstruction by endogenous fibrinolysis or attenuation of adverse pulmonary vasoconstriction is unknown. Purpose To investigate the contribution of the mechanical obstruction and pulmonary vasoconstriction to PVR in two days following PE in pigs. Methods In a controlled animal study, using an estabilished model of autologous PE in pigs (PE, n=12 ∼60 kg), changes in pulmonary hemodynamics and clot burden were evaluated. CT pulmonary angiograms were performed at baseline (BL), after acute PE and the following two days, quantifying clot burden using the Qanadli Obstruction Score. Hemodynamics were evaluated with real-time biventricular catheterization and systemic invasive pressures. To evaluate the vasoactive component, pulmonary vasodilators sildenafil (bolus 0.1 mg/kg) and oxygen (inspired fraction of oxygen 40%) were administered. Results Following PE, both mean PVR (Figure 1A) and pulmonary obstruction scores (Figure 1B) increased. PVR decreased at day one and remained unchanged at day two (Figure 1A). Meanwhile, mean obstruction score decreased slightly at day one but remained elevated throughout the study (Figure 1B). Vasodilatation induced by sildenafil and oxygen (SIL+OXY) decreased PVR at day zero but displayed no effect on the subsequent days (Figure 1A). Conclusion Pulmonary vasoconstriction and mechanical obstruction both contributed to the increase in PVR during the acute phase of PE. PVR decreased towards levels of baseline already day one and remained unchanged at day two. The contribution of pulmonary vasoconstriction decreased at day one and two, while the mechanical obstruction remained significantly increased. Accordingly, the effects of pulmonary vasodilators were only present in the acute phase of PE.Figure 1