The Role of Fibrinolytic System in Health and Disease

Polystyrene nanoplastics enhance thrombosis through adsorption of plasma proteins

Plastic products offer remarkable convenience for modern life. However, growing concerns are emerging regarding the potential health hazards posed by nanoplastics, which formed as plastics break down. Currently, the biological effects and mechanisms induced by nanoplastics are largely underexplored. In this study, we report that polystyrene nanoplastics can enter the bloodstream and enhance thrombus formation. Our findings show that polystyrene nanoplastics adsorb plasma proteins, particularly coagulation factor XII and plasminogen activator inhibitor-1, play a key role in this process, as demonstrated by proteomics, bioinformatic analyses, and molecular dynamics simulations. The adsorption of these proteins by nanoplastics is an essential factor in thrombosis enhancement. This newly uncovered pathway of protein adsorption leading to enhanced thrombosis provides new insights into the biological effects of nanoplastics, which may inform future safety and environmental risk assessment of plastics.

Cerebral Angiography and Neurobehavioral Patterns in a Non-human Primate Middle Cerebral Artery Occlusion Model

BACKGROUND/AIM

Ischemic stroke is a major health concern globally and developing reliable animal models is crucial for understanding its pathophysiology. This study evaluated the relationship between cerebral angiographic findings and neurologic dysfunction in an acute non-human primate thromboembolic stroke model and determined the minimum clot length for suitable middle cerebral artery (MCA) occlusion.

MATERIALS AND METHODS

A thromboembolic stroke model was developed by injecting autologous blood clots (length: 1, 2, 3, 4, 5, and 10 cm, n=1 to 3, 14 monkeys in total) into the internal carotid artery of male cynomolgus monkeys. Digital subtraction angiography (DSA) and neurologic deficit observation were performed pre-; immediately after (DSA only); and 1, 3, 6, and 24 h after embolization, and the relationship between clot length, neurologic deficits, and cerebral infarction was assessed.

RESULTS

DSA confirmed MCA occlusion in all animals after the clot injection. Recanalization of the MCA was observed within 6 h post-embolization in animals with shorter clots (≤3 cm). Neurologic deficits were evident in animals with MCA occlusion and correlated with the clot length. Larger clots (≥5 cm) led to permanent MCA occlusion, significant neurologic deficits, and extensive cerebral infarction. Histopathological examination revealed ischemic damage in brain regions corresponding to the infarcted areas.

CONCLUSION

Clot length is critical in determining the extent of neurologic dysfunction and cerebral infarction, with larger clots producing more severe outcomes. Furthermore, the minimum clot length required for model creation is 5 cm.

PLAUR facilitates the progression of clear cell renal cell carcinoma by activating the PI3K/AKT/mTOR signaling pathway

Background

PLAUR has been found upregulated in various tumors and closely correlated with the malignant phenotype of tumor cells. The aim of this study was to investigate the relationship between PLAUR and clear cell renal cell carcinoma (ccRCC) and its potential mechanism of promoting tumor progression.

Methods

The expression levels and clinical significance of PLAUR, along with the associated signaling pathways, were extensively investigated in ccRCC samples obtained from The Cancer Genome Atlas (TCGA). PLAUR expression in 20 pairs of ccRCC tumor tissues and the adjacent tissues was assessed using qRT-PCR and IHC staining. Additionally, a series of in vitro experiments were conducted to investigate the impact of PLAUR suppression on cellular proliferation, migration, invasion, cell cycle progression, and apoptosis in ccRCC. The Western blot analysis was employed to investigate the expression levels of pivotal genes associated with the PI3K/AKT/mTOR signaling pathway.

Results

The expression of PLAUR was significantly upregulated in ccRCC compared to normal renal tissues, and higher PLAUR expression in ccRCC was associated with a poorer prognosis than low expression. The in-vitro functional investigations demonstrated that knockdown of PLAUR significantly attenuated the proliferation, migration, and invasion capabilities of ccRCC cells. Concurrently, PLAUR knockdown effectively induced cellular apoptosis, modulated the cell cycle, inhibited the EMT process, and attenuated the activation of the PI3K/AKT/mTOR signaling pathway. PLAUR may represent a key mechanism underlying ccRCC progression.

Conclusions

The involvement of PLAUR in ccRCC progression may be achieved through the activation of the PI3K/AKT/mTOR signaling pathway, making it a reliable biomarker for the identification and prediction of ccRCC.

The interaction between oral microbiota and gut microbiota in atherosclerosis

Atherosclerosis (AS) is a complex disease caused by multiple pathological factors threatening human health-the pathogenesis is yet to be fully elucidated. In recent years, studies have exhibited that the onset of AS is closely involved with oral and gut microbiota, which may initiate or worsen atherosclerotic processes through several mechanisms. As for how the two microbiomes affect AS, existing mechanisms include invading plaque, producing active metabolites, releasing lipopolysaccharide (LPS), and inducing elevated levels of inflammatory mediators. Considering the possible profound connection between oral and gut microbiota, the effect of the interaction between the two microbiomes on the initiation and progression of AS has been investigated. Findings are oral microbiota can lead to gut dysbiosis, and exacerbate intestinal inflammation. Nevertheless, relevant research is not commendably refined and a concrete review is needed. Hence, in this review, we summarize the most recent mechanisms of the oral microbiota and gut microbiota on AS, illustrate an overview of the current clinical and epidemiological evidence to support the bidirectional connection between the two microbiomes and AS.

Targeted drug delivery to the thrombus by fusing streptokinase with a fibrin-binding peptide (CREKA): an in silico study

Aim: Streptokinase has poor selectivity and provokes the immune response. In this study, we used in silico studies to design a fusion protein to achieve targeted delivery to the thrombus. Materials & methods: Streptokinase was analyzed computationally for mapping. The fusion protein modeling and quality assessment were carried out on several servers. The enzymatic activity and the stability of the fusion protein and its complex with plasminogen were assessed through molecular docking analysis and molecular dynamics simulation respectively. Results: Physicochemical properties analysis, protein quality assessments, protein-protein docking and molecular dynamics simulations predicted that the designed fusion protein is functionally active. Conclusion: Our results showed that this fusion protein might be a prospective candidate as a novel thrombolytic agent with better selectivity.

Dysregulated fibrinolysis and plasmin activation promote the pathogenesis of osteoarthritis

Joint injury is associated with risk for development of osteoarthritis (OA). Increasing evidence suggests that activation of fibrinolysis is involved in OA pathogenesis. However, the role of the fibrinolytic pathway is not well understood. Here, we showed that the fibrinolytic pathway, which includes plasminogen/plasmin, tissue plasminogen activator, urokinase plasminogen activator (uPA), and the uPA receptor (uPAR), was dysregulated in human OA joints. Pharmacological inhibition of plasmin attenuated OA progression after a destabilization of the medial meniscus in a mouse model whereas genetic deficiency of plasmin activator inhibitor, or injection of plasmin, exacerbated OA. We detected increased uptake of uPA/uPAR in mouse OA joints by microPET/CT imaging. In vitro studies identified that plasmin promotes OA development through multiple mechanisms, including the degradation of lubricin and cartilage proteoglycans and induction of inflammatory and degradative mediators. We showed that uPA and uPAR produced inflammatory and degradative mediators by activating the PI3K, 3'-phosphoinositide-dependent kinase-1, AKT, and ERK signaling cascades and activated matrix metalloproteinases to degrade proteoglycan. Together, we demonstrated that fibrinolysis contributes to the development of OA through multiple mechanisms and suggested that therapeutic targeting of the fibrinolysis pathway can prevent or slow development of OA.

[Factors of the hemostasis system as biomarkers of severe course of acute viral infections]

The authors give literature review of hemostasis and immune system factors intraction as main biomarkers of a severe cause of viral infectious diseases. Pro-inflamatory cytokines as the main markers of inflammation, can serve both as biomarkers of the clinical severity of the infectious process and reflect the state of the hemostatic and fibrinolytic systems, since components of these systems are present in various structures of the central nervous system and affect the development of neurons and synaptic plasticity. An inverse correlation has been proven between the concentration of D-dimer and the oxygenation index, and the development of DIC is not associated with the presence of respiratory failure in patients with influenza type A, while the ferritin concentration directly reflects the severity of the disease. One of the markers of endothelial damage may be soluble thrombomodulin, which, however, is rarely used in routine clinical practice. Cytoflavin is a highly effective pathogenetic drug that affects various parts of the hemostasis system, has anti-ischemic, antioxidant, antihypoxic, immunocorrective effect, which is indicated for any generalized infectious disease since its debut.

Fibrinolytic system and COVID-19: From an innovative view of epithelial ion transport

Lifeways of worldwide people have changed dramatically amid the coronavirus disease 2019 (COVID-19) pandemic, and public health is at stake currently. In the early stage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, fibrinolytic system is mostly inhibited, which is responsible for the development of hypofibrinolysis, promoting disseminated intravascular coagulation, hyaline membrane formation, and pulmonary edema. Whereas the common feature and risk factor at advanced stage is a large amount of fibrin degradation products, including D-dimer, the characteristic of hyperfibrinolysis. Plasmin can cleave both SARS-CoV-2 spike protein and γ subunit of epithelial sodium channel (ENaC), a critical element to edematous fluid clearance. In this review, we aim to sort out the role of fibrinolytic system in the pathogenesis of COVID-19, as well as provide the possible guidance in current treating methods. In addition, the abnormal regulation of ENaC in the occurrence of SARS-CoV-2 mediated hypofibrinolysis and hyperfibrinolysis are summarized, with the view of proposing an innovative view of epithelial ion transport in preventing the dysfunction of fibrinolytic system during the progress of COVID-19.

Markers of Hereditary Thrombophilia with Unclear Significance

Thrombophilia leads to an increased risk of venous thromboembolism. Widely accepted risk factors for thrombophilia comprise deficiencies of protein C, protein S, and antithrombin, as well as the factor V "Leiden" mutation, the prothrombin G20210A mutation, dysfibrinogenemia, and, albeit less conclusive, increased levels of factor VIII. Besides these established markers of thrombophilia, risk factors of unclear significance have been described in the literature. These inherited risk factors include deficiencies or loss-of-activity of the activity of ADAMTS13, heparin cofactor II, plasminogen, tissue factor pathway inhibitor (TFPI), thrombomodulin, protein Z (PZ), as well as PZ-dependent protease inhibitor. On the other hand, thrombophilia has been linked to the gain-of-activity, or elevated levels, of α2-antiplasmin, angiotensin-converting enzyme, coagulation factors IX (FIX) and XI (FXI), fibrinogen, homocysteine, lipoprotein(a), plasminogen activator inhibitor-1 (PAI-1), and thrombin-activatable fibrinolysis inhibitor (TAFI). With respect to the molecular interactions that may influence the thrombotic risk, more complex mechanisms have been described for endothelial protein C receptor (EPCR) and factor XIII (FXIII) Val34Leu. With focus on the risk for venous thrombosis, the present review aims to give an overview on the current knowledge on the significance of the aforementioned markers for thrombophilia screening. According to the current knowledge, there appears to be weak evidence for a potential impact of EPCR, FIX, FXI, FXIII Val34Leu, fibrinogen, homocysteine, PAI-1, PZ, TAFI, and TFPI on the thrombotic risk.

A Novel Marine Pyran-Isoindolone Compound Enhances Fibrin Lysis Mediated by Single-Chain Urokinase-Type Plasminogen Activator

Fungi fibrinolytic compound 1 (FGFC1) is a rare pyran-isoindolone derivative with fibrinolytic activity. The aim of this study was to further determine the effect of FGFC1 on fibrin clots lysis in vitro. We constructed a fibrinolytic system containing single-chain urokinase-type plasminogen activator (scu-PA) and plasminogen to measure the fibrinolytic activity of FGFC1 using the chromogenic substrate method. After FITC-fibrin was incubated with increasing concentrations of FGFC1, the changes in the fluorescence intensity and D-dimer in the lysate were measured using a fluorescence microplate reader. The fibrin clot structure induced by FGFC1 was observed and analyzed using a scanning electron microscope and laser confocal microscope. We found that the chromogenic reaction rate of the mixture system increased from (15.9 ± 1.51) × 10−3 min−1 in the control group to (29.7 ± 1.25) × 10−3 min−1 for 12.8 μM FGFC1(p < 0.01). FGFC1 also significantly increased the fluorescence intensity and d-dimer concentration in FITC fibrin lysate. Image analysis showed that FGFC1 significantly reduced the fiber density and increased the fiber diameter and the distance between protofibrils. These results show that FGFC1 can effectively promote fibrin lysis in vitro and may represent a novel candidate agent for thrombolytic therapy.