Corrigendum: Urokinase-type plasminogen activator and plasminogen activator inhibitor-1 complex as a serum biomarker for COVID-19

[This corrects the article DOI: 10.3389/fimmu.2023.1299792.].

Plasminogen activator inhibitor-1 serum levels in frontotemporal lobar degeneration

Plasminogen activator inhibitor-1 (PAI-1) impedes brain plasmin synthesis. Reduced plasmin activity facilitates cumulation of amyloid beta (Aβ) in Alzheimer's disease (AD). Since plasmin also regulates the synaptic activity, it is possible that altered PAI-1 is present in other neurodegenerative disorders. We investigated whether PAI-1 and its counter-regulatory tissue plasminogen activator (tPA) are altered in serum of patients with dementia due to frontotemporal lobar degeneration (FTLD). Thirty five FTLD patients (21 in mild cognitive impairment stage (MCI) and 14 in dementia stage) and 10 cognitively healthy controls were recruited. Serum tPA and PAI-1 protein levels were measured by anova. Correlation between biochemical and demographic data were explored by measuring Pearson correlation coefficient. Serum PAI-1 levels were elevated in the FTLD dementia group as compared to FTLD MCI and controls. tPA serum levels and PAI-1/tPA ratio did not significantly differ among groups. There was a negative correlation between PAI-1 serum levels and disease severity measured by MMSE score. No correlations of tPA serum levels and PAI-1/tPA ratio with MMSE were found. Increased PAI-1 serum levels may serve as a marker of dementia in FTLD, suggesting that, besides Aβ pathway, the plasmin system may affect cognition through synaptic activity.

Urokinase-type plasminogen activator and plasminogen activator inhibitor-1 complex as a serum biomarker for COVID-19

Patients with coronavirus disease-2019 (COVID-19) have an increased risk of thrombosis and acute respiratory distress syndrome (ARDS). Thrombosis is often attributed to increases in plasminogen activator inhibitor-1 (PAI-1) and a shut-down of fibrinolysis (blood clot dissolution). Decreased urokinase-type plasminogen activator (uPA), a protease necessary for cell-associated plasmin generation, and increased tissue-type plasminogen activator (tPA) and PAI-1 levels have been reported in COVID-19 patients. Because these factors can occur in free and complexed forms with differences in their biological functions, we examined the predictive impact of uPA, tPA, and PAI-1 in their free forms and complexes as a biomarker for COVID-19 severity and the development of ARDS. In this retrospective study of 69 Japanese adults hospitalized with COVID-19 and 20 healthy donors, we found elevated free, non-complexed PAI-1 antigen, low circulating uPA, and uPA/PAI-1 but not tPA/PAI-1 complex levels to be associated with COVID-19 severity and ARDS development. This biomarker profile was typical for patients in the complicated phase. Lack of PAI-1 activity in circulation despite free, non-complexed PAI-1 protein and plasmin/α2anti-plasmin complex correlated with suPAR and sVCAM levels, markers indicating endothelial dysfunction. Furthermore, uPA/PAI-1 complex levels positively correlated with TNFα, a cytokine reported to trigger inflammatory cell death and tissue damage. Those levels also positively correlated with lymphopenia and the pro-inflammatory factors interleukin1β (IL1β), IL6, and C-reactive protein, markers associated with the anti-viral inflammatory response. These findings argue for using uPA and uPA/PAI-1 as novel biomarkers to detect patients at risk of developing severe COVID-19, including ARDS.

Extracellular vesicles from periodontal pathogens regulate hepatic steatosis via Toll-like receptor 2 and plasminogen activator inhibitor-1

Plasminogen activator inhibitor-1 (PAI-1) is associated with nonalcoholic fatty liver disease (NAFLD) by lipid accumulation in the liver. In this study, we showed that extracellular vesicles (EVs) from the periodontal pathogens Filifactor alocis and Porphyromonas gingivalis induced steatosis by inducing PAI-1 in the liver and serum of mice fed a low-fat diet. PAI-1 induction was not observed in TLR2-/- mice. When tested using HEK-Blue hTLR2 cells, human TLR2 reporter cells, the TLR2-activating ability of serum from NAFLD patients (n = 100) was significantly higher than that of serum from healthy subjects (n = 100). Correlation analysis confirmed that PAI-1 levels were positively correlated with the TLR2-activating ability of serum from NAFLD patients and healthy subjects. Amphiphilic molecules in EVs were involved in PAI-1 induction. Our data demonstrate that the TLR2/PAI-1 axis is important for hepatic steatosis by EVs of periodontal pathogens.

Effect of daily ingestion of Bifidobacterium and dietary fiber on vascular endothelial function: a randomized, double-blind, placebo-controlled, parallel-group comparison study

Bifidobacterium animalis subsp. lactis GCL2505 (GCL2505) improves the intestinal microbiota and reduces human visceral fat. This randomized, double-blind, placebo-controlled, parallel-group study was conducted to examine the effects of inulin, a prebiotic dietary fiber, and GCL2505 on vascular endothelial function in healthy subjects (n = 60). The test drink contained 2.0 g/100 g inulin and 1.0 × 1010 colony-forming units/100 g GCL2505 and was consumed daily for 12 weeks. Flow-mediated dilation was set as the primary endpoint. Subgroup analysis of vascular endothelial function demonstrated a significant increase in the change of flow-mediated dilation (%) from weeks 0 to 12 in the GCL2505 and inulin group (n = 24) compared with the placebo group (n = 23), while an improving trend in low-density lipoprotein cholesterol and plasminogen activator inhibitor-1 were confirmed. Our results indicated that the test drink had a positive effect on vascular endothelial function and related blood parameters.

Recent Advances on the Molecular Mechanism and Clinical Trials of Venous Thromboembolism

Venous thromboembolism is a condition that includes deep vein thrombosis and pulmonary embolism. It is the third most common cardiovascular disease behind acute coronary heart disease and stroke. Over the past few years, growing research suggests that venous thrombosis is also related to the immune system and inflammatory factors have been confirmed to be involved in venous thrombosis. The role of inflammation and inflammation-related biomarkers in cerebrovascular thrombotic disease is the subject of ongoing debate. P-selectin leads to platelet-monocyte aggregation and stimulates vascular inflammation and thrombosis. The dysregulation of miRNAs has also been reported in venous thrombosis, suggesting the involvement of miRNAs in the progression of venous thrombosis. Plasminogen activator inhibitor-1 (PAI-1) is a crucial component of the plasminogen-plasmin system, and elevated levels of PAI-1 in conjunction with advanced age are significant risk factors for thrombosis. In addition, it has been showed that one of the ways that neutrophils promote venous thrombosis is the formation of neutrophil extracellular traps (NETs). In recent years, the role of extracellular vesicles (EVs) in the occurrence and development of VTE has been continuously revealed. With the advancement of research technology, the complex regulatory role of EVs on the coagulation process has been gradually discovered. However, our understanding of the causes and consequences of these changes in venous thrombosis is still limited. Therefore, we review our current understanding the molecular mechanisms of venous thrombosis and the related clinical trials, which is crucial for the future treatment of venous thrombosis.

The role of fibrinolysis in the development of prediabetes-associated coronary heart disease: a focus on the plasminogen activator inhibitor -1 and its potential use as a predictive marker in diet-induced prediabetes

Introduction

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of cardiovascular diseases (CVD). However, the onset of T2DM is preceded by prediabetes, which is associated with sedentary lifestyles and consumption of high-calorie diets. Studies have shown that impaired glucose homeostasis creates an environment for developing T2DM-related complications. Using a high-fat-high-carbohydrate diet-induced prediabetes animal model, this study sought to assess the risk factors of coronary heart disease (CHD) in diet-induced prediabetes and identify biomarkers that can be used for early detection of prediabetes-associated CHD.

Methods

Male Sprague Dawley rats were randomly grouped into two groups and were kept on different diets for 20 weeks (n = 6 in each group). One group was fed standard rat chow to serve as a non-prediabetes (NPD) control, while the other group consumed a high-fat-high-carbohydrate diet to induce prediabetes (PD). Post induction, the homeostasis model assessment- insulin resistance (HOMA-IR) and glycated haemoglobin (HbA1c) was used to test for insulin resistance. Body weight, mean arterial pressure (MAP), resting heart rate (HR), inflammatory cytokines (C-reactive protein (CRP), tumor necrosis factor (TNF-α), interleukin-6 (IL-6)), lipids (total cholesterol (TC), triglyceride (TG), lipoproteins (HDL, LDL, VLDL)), endothelial function (endothelial nitric oxide (eNOS), endothelin -1 (ET-1)), fibrinolysis (plasminogen activator inhibitor-1 (PAI-1)) were all measured to assess the risk of CHD. All data were expressed as means ± S.E.M. Statistical comparisons were performed with Graph Pad. Instat Software using Student's two-sided t-test. The Pearson correlation coefficient and linear regression were calculated to assess the association. The value of p < 0.05 was considered statistically significant.

Results

There was significant insulin resistance accompanied by significantly increased HbA1c and body weight in PD compared to NPD. Simultaneously, there was a significant increase in inflammatory cytokines in PD compared to NPD. This was accompanied by significantly increased TG and VLDL and endothelial dysfunction in PD. The association between HOMA-IR and PAI-1 was insignificantly positive in NPD, whereas a significantly strong positive association was observed in PD.

Conclusion

There is a positive correlation between insulin resistance and PAI-1 during prediabetes; therefore, suggesting that prediabetes increases the risk of developing vascular thrombosis. The current therefore study warrants further investigation on PAI-1 and other markers of fibrinolysis for the early detection of thrombosis and risk of CHD in prediabetes.

Association of plasminogen activator inhibitor-1 and fibroblastic growth factor 21 in 3 groups of type 2 diabetes: Without overweight/obesity, free of insulin resistance, and without hepatosteatosis

The physiological effects of fibroblast growth factor 21 (FGF21), leading to beneficial metabolic outcomes, have been extensively revealed in recent decades. Significantly elevated serum levels of FGF21 in obesity and type 2 diabetes mellitus (T2DM) are referred to as FGF21 resistance. However, Asian population tend to develop metabolic disorders at a lesser degree of obesity than those of Western. This study aimed to explore factors potentially related to serum FGF21 according to the severity of metabolic disorders in patients with T2DM. This cross-sectional study included 176 T2DM patients. The patients were categorized according to whether they had hepatic steatosis (fatty liver index [FLI] ≥ 60), insulin resistance (homeostasis model assessment of insulin resistance [HOMA-R] ≥ median), and/or overweight/obesity (body mass index [BMI] ≥ 25.0 kg/m2). Independent predictors of serum FGF21 were determined using multiple linear regression analysis in these 3 groups of T2DM patients. Circulating FGF21 levels were correlated positively with BMI, abdominal fat areas, leptin, and plasminogen activator inhibitor-1 (PAI-1). After adjustment for potential confounders, multiple linear regression analysis identified leptin as a factor strongly associated with serum FGF21 levels in all patients. Moreover, PAI-1 was a significant predictor of FGF21 in those with FLI < 60, BMI < 25.0 kg/m2, and HOMA-R < median, while leptin was the only independent factor in each of their counterparts. The factors related to serum FGF21 differ according to the severity of metabolic disorders. FGF21 appears to be independently associated with PAI-1 in T2DM patients: without overweight/obesity, those free of insulin resistance, and those without hepatic steatosis.

Suppression of antitumor cytokine IL‑24 by PRG4 and PAI‑1 may promote myxoid liposarcoma cell survival

Suppression of the antitumor cytokine interleukin-24 (IL-24) is critical for the survival of myxoid liposarcoma (MLS) cells. It has been previously demonstrated by the authors that an MLS-specific chimeric oncoprotein, translocated in liposarcoma-CCAAT/enhancer-binding protein homologous protein (TLS-CHOP), supresses IL24 mRNA expression via induction of proteoglycan 4 (PRG4) to sustain MLS cell proliferation. However, IL-24 has also been revealed to be suppressed by the ubiquitin-proteasome system in human ovarian and lung cancer cells. Therefore, the aim of the present study was to elucidate the mechanism of IL-24 suppression in MLS cells. The results revealed that the proteasome inhibitor, MG-132, induced cell death in MLS cells in vitro; this effect was reduced following IL-24 knockdown. This indicated that proteasomal degradation of IL-24 may be an important process for MLS cell survival. In addition, it was also previously revealed by the authors that knockdown of plasminogen activator inhibitor-1 (PAI-1), a TLS-CHOP downstream molecule, suppressed the growth of MLS cells, thus instigating the investigation of the effect of PAI-1 on IL-24 expression in MLS cells. Double knockdown of PAI-1 and IL-24 negated the growth-suppressive effect of PAI-1 single knockdown in MLS cells. Interestingly, PAI-1 single knockdown did not increase the mRNA expression of IL24, but it did increase the protein abundance of IL-24, indicating that PAI-1 suppressed IL-24 expression by promoting its proteasomal degradation. Moreover, treatment of MLS cells with a PAI-1 inhibitor, TM5275, induced IL-24 protein expression and apoptosis. Collectively, the results of the present as well as previous studies indicated that IL-24 expression may be suppressed at the transcriptional level by PRG4 and at the protein level by PAI-1 in MLS cells. Accordingly, PAI-1 may represent an effective therapeutic target for MLS treatment.

Increased glutamate in type 2 diabetes in the Korean population is associated with increased plasminogen levels

BACKGROUND

Glutamate is a major neurotransmitter, although it causes cytotoxicity and inflammation in nonneuronal organs. This study aimed to investigate the metabolic disorders in which glutamate, associated with type 2 diabetes onset, is induced in the liver.

METHODS

An analysis of Korean community-based Ansan-Ansung cohort study data as well as functional research using in vitro and mouse models were performed.

RESULTS

Groups with high plasma glutamate levels (T2, T3) had a significantly increased risk of diabetes incidence after 8 years, compared to the group with relatively low glutamate levels (T1). Analysis of the effect of glutamate on diabetes onset in vitro showed that glutamate induces insulin resistance by increasing glucose-related protein 78 (GRP78) and phosphoenolpyruvate carboxykinase (PEPCK) expression in SK-Hep-1 human liver cells. In addition, three different genes, FRMB4B, PLG, and PARD3, were significantly associated with glutamate and were identified via genome-wide association studies. Among glutamate-related genes, plasminogen (PLG) levels were most significantly increased in several environments in which insulin resistance was induced, and was also upregulated by glutamate. Glutamate-induced increase in PLG in liver cells was caused by metabotropic glutamate receptor 5 activation, and PLG levels were also upregulated after extracellular secretion. Moreover, glutamate increased the expression of plasminogen activator inhibitor-1 (PAI-1). Thus, extracellular secreted PLG cannot be converted to plasmin (fibrinolytic enzyme) by increased PAI-1.

CONCLUSIONS

Increased glutamate is closely associated with the development of diabetes, and it may cause metabolic disorders by inhibiting the fibrinolytic system, which plays an important role in determining blood clots, a hallmark of diabetes.

PAI-1 genetic polymorphisms influence septic patients' outcomes by regulating neutrophil activity

BACKGROUND

Plasminogen activator inhibitor-1 (PAI-1) plays an important role in the pathophysiology of sepsis, but the exact mechanism remains debatable. In this study, we investigated the associations among the serum levels of PAI-1, the incidence of 4G/5G promoter PAI-1 gene polymorphisms, immunological indicators, and clinical outcomes in septic patients.

METHODS

A total of 181 patients aged 18-80 years with sepsis between November 2016 and August 2018 in the intensive care unit in the Xinhua Hospital were recruited in this retrospective study, with 28-day mortality as the primary outcome. The initial serum level of PAI-1 and the presence of rs1799768 single nucleotide polymorphisms (SNPs) were examined. Univariate logistic regression and multivariate analyses were performed to determine the factors associated with different genotypes of PAI-1, serum level of PAI-1, and 28-day mortality.

RESULTS

The logistic analysis suggested that a high serum level of PAI-1 was associated with the rs1799768 SNP of PAI-1 (4G/4G and 4G/5G) (Odds ratio [OR]: 2.49; 95% confidence interval [CI]: 1.09, 5.68). Furthermore, a high serum level of PAI-1 strongly influenced 28-day mortality (OR 3.36; 95% CI 1.51, 7.49). The expression and activation of neutrophils (OR 0.96; 95% CI 0.93, 0.99), as well as the changes in the expression patterns of cytokines and chemokine-associated neutrophils (OR: 1.00; 95% CI: 1.00, 1.00), were both regulated by the genotype of PAI-1.

CONCLUSIONS

Genetic polymorphisms of PAI-1 can influence the serum levels of PAI-1, which might contribute to mortality by affecting neutrophil activity. Thus, patients with severe sepsis might clinically benefit from enhanced neutrophil clearance and the resolution of inflammation via the regulation of PAI-1 expression and activity.

Serum lipoprotein(a), and plasminogen activator inhibitor-1 in uncomplicated type 2 diabetes mellitus: a case-control study

Increased levels of lipoprotein (a) [Lp(a)] are indicative of coronary artery disease (CAD). Dyslipidemia, which is an established risk factor for CAD, is also an additional adverse effect of uncontrolled type 2 diabetes. Procoagulant and fibrinolytic indicators have been linked to the development of type 2 diabetes. Plasminogen activator inhibitor-1 (PAI-1), plays a significant negative regulatory role in fibrinolysis, through its function as the main inhibitor of tissue plasminogen activator. This study was designed to investigate the levels of Lp(a) and PAI-1 in uncomplicated type 2 diabetic patients and their association with healthy controls.

MATERIALS AND METHODS

A case-control study designed for the estimation of Lp(a) and PAI-1 in serum after collecting blood samples from type 2 diabetic patients at the Layla Qasim Diabetic Center in Erbil, Iraq. The study included 90 participants, of whom 30 were healthy controls (15 males and 15 females). The remaining 60 cases were patients with type 2 diabetes with a duration of up to 6 years (30 males and 30 females).

RESULTS

Serum Lp(a) and PAI-1 levels were significantly lower in type 2 diabetic patients than in controls (P<0.01), this is an opposite result that usually happen in uncontrolled and complicated diabetic patients.

CONCLUSIONS

The results were clearly stated a beneficial effect of Metformin on the levels of Lp(a) and PAI-1 in type 2 diabetes, so lowering their concentrations would help prevention of CAD, a known cause of death in diabetic patients.

Exploring the Therapeutic Potential of Apigenin in Obesity-Associated Fibrinolytic Dysfunction: Insights From an Animal Study

INTRODUCTION

Obesity (Obe) is a chronic metabolic disorder usually complicated by impaired fibrinolytic activity. Apigenin (Api) is one of the flavonoids that have anti-adiposity effects. This study aimed to explore the therapeutic potential of Api in high-fat diet (HFD)-induced obese rats.

METHODS

Twenty-four Wistar adult male rats were randomly allocated into control group, supplemented with a normal pellet diet (NPD); Api group, supplemented with Api (10 mg/kg) for eight weeks; Obe group, obesity was induced by feeding HFD for eight weeks; and Obe/Api group, obese rats supplemented with Api for eight weeks. Body mass index (BMI), homeostatic model assessment of insulin resistance (HOMA-IR), tumor necrosis factor-α (TNF-α), malondialdehyde (MDA), total superoxide dismutase (t-SOD) activity, and plasminogen activator inhibitor-1 (PAI-1) were measured.

RESULTS

Compared to the control group, Obe group exhibited a significant increase in BMI, HOMA-IR, TNF-α, MDA, and PAI-1. These results were also associated with a significant decrease in serum t-SOD activity. Supplementation of Api alleviated the measured deteriorated parameters and ameliorated visceral adiposity in obese rats.

CONCLUSION

This study provides compelling evidence regarding a promising role for Api in ameliorating the impairment of fibrinolytic activity in an Obe animal model. The observed effects are likely mediated through Api's anti-obesity properties, as well as its indirect modulation of PAI-1, oxidative stress, and inflammation. Future clinical studies are recommended that may make benefit of the preclinical therapeutic use of apigenin in obesity-associated fibrinolytic dysfunctions.

The 14-Kilodalton Human Growth Hormone Fragment a Potent Inhibitor of Angiogenesis and Tumor Metastasis

The 14-kilodalton human growth hormone (14 kDa hGH) N-terminal fragment derived from the proteolytic cleavage of its full-length counterpart has been shown to sustain antiangiogenic potentials. This study investigated the antitumoral and antimetastatic effects of 14 kDa hGH on B16-F10 murine melanoma cells. B16-F10 murine melanoma cells transfected with 14 kDa hGH expression vectors showed a significant reduction in cellular proliferation and migration associated with an increase in cell apoptosis in vitro. In vivo, 14 kDa hGH mitigated tumor growth and metastasis of B16-F10 cells and was associated with a significant reduction in tumor angiogenesis. Similarly, 14 kDa hGH expression reduced human brain microvascular endothelial (HBME) cell proliferation, migration, and tube formation abilities and triggered apoptosis in vitro. The antiangiogenic effects of 14 kDa hGH on HBME cells were abolished when we stably downregulated plasminogen activator inhibitor-1 (PAI-1) expression in vitro. In this study, we showed the potential anticancer role of 14 kDa hGH, its ability to inhibit primary tumor growth and metastasis establishment, and the possible involvement of PAI-1 in promoting its antiangiogenic effects. Therefore, these results suggest that the 14 kDa hGH fragment can be used as a therapeutic molecule to inhibit angiogenesis and cancer progression.

Resistin Contribution to Cardiovascular Risk in Chronic Kidney Disease Male Patients

BACKGROUND

Resistin is a molecule that belongs to the Resistin-Like Molecules family (RELMs), the group of proteins taking part in inflammatory processes. Increased resistin concentrations are observed in cardiovascular complications. Resistin contributes to the onset of atherosclerosis and intensifies the atherosclerotic processes. The aim of this study was to investigate the relationship between resistin and cardiovascular (CV) risk in men with chronic kidney disease (CKD) not treated with dialysis.

MATERIALS AND METHODS

One hundred and forty-two men were included in the study: 99 men with eGFR lower than 60 mL/min/1.73 m² and 43 men with eGFR ≥ 60 mL/min/1.73 m². CV risk was assessed. Serum resistin, tumor necrosis factor-alpha (TNF-alpha) and plasminogen activator inhibitor-1 (PAI-1) were measured among other biochemical parameters.

RESULTS

We observed that resistin concentrations were significantly higher in patients with CKD compared to individuals with eGFR ≥ 60 mL/min/1.73 m² (p = 0.003). In CKD, after estimating the general linear model (GLM), we found that resistin is associated with CV risk (p = 0.026) and PAI-1 serum concentrations (0.012). The relationship of PAI-1 with resistin depends on the level of CV risk in CKD (p = 0.048).

CONCLUSIONS

Resistin concentrations rise with the increase of CV risk in CKD patients and thus resistin may contribute to the progression of cardiovascular risk in this group of patients. The relationship between resistin and CV risk is modified by PAI-1 concentrations.

Association of SNPs in the PAI1 Gene with Disease Recurrence and Clinical Outcome in Bladder Cancer

PURPOSE

Bladder cancer (BCa) is one of the most common cancer types worldwide and is characterized by a high rate of recurrence. In previous studies, we and others have described the functional influence of plasminogen activator inhibitor-1 (PAI1) in bladder cancer development. While polymorphisms in PAI1 have been associated with increased risk and worsened prognosis in some cancers, the mutational status of PAI1 in human bladder tumors has not been well defined.

METHODS

In this study, we evaluated the mutational status of PAI1 in a series of independent cohorts, comprised of a total of 660 subjects.

RESULTS

Sequencing analyses identified two clinically relevant 3' untranslated region (UTR) single nucleotide polymorphisms (SNPs) in PAI1 (rs7242; rs1050813). Somatic SNP rs7242 was present in human BCa cohorts (overall incidence of 72%; 62% in Caucasians and 72% in Asians). In contrast, the overall incidence of germline SNP rs1050813 was 18% (39% in Caucasians and 6% in Asians). Furthermore, Caucasian patients with at least one of the described SNPs had worse recurrence-free survival and overall survival (p = 0.03 and p = 0.03, respectively). In vitro functional studies demonstrated that SNP rs7242 increased the anti-apoptotic effect of PAI1, and SNP rs1050813 was related to a loss of contact inhibition associated with cellular proliferation when compared to wild type.

CONCLUSION

Further investigation of the prevalence and potential downstream influence of these SNPs in bladder cancer is warranted.

Association between Plasminogen Activator Inhibitor-1 and Osimertinib Tolerance in EGFR-Mutated Lung Cancer via Epithelial-Mesenchymal Transition

Most epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer (NSCLC) cells are killed within a few days after osimertinib treatment; however, surviving cells remain detectable and are called drug-tolerant cells. Plasminogen activator inhibitor-1 (PAI-1) was reported to be involved in chemotherapeutic or radiotherapeutic resistance. The purpose of the present study was to investigate whether PAI-1 is involved in osimertinib tolerance and whether it could be a therapeutic target for overcoming this tolerance. We showed that the PAI-1 mRNA expression levels and mesenchymal gene expression levels were significantly higher in drug-tolerant EGFR-mutated NSCLC cells than in control cells after 7 days of in vitro osimertinib treatment. Additionally, an RNA microarray analysis revealed upregulation of the integrin-induced EMT pathway in osimertinib-tolerant cells. Furthermore, we observed that PAI-1 inhibitors suppressed proliferation and the degree of epithelial-mesenchymal transition (EMT) in tolerant cells. Finally, in a subcutaneous tumor model, we showed that combining osimertinib with a PAI-1 inhibitor prevented the regrowth of tumors comprising EGFR-mutated cancer cells. The present study is the first to show PAI-1 to be involved in tolerance to osimertinib via EMT.

Effect of Peptides from Plasma of Patients with Coronary Artery Disease on the Vascular Endothelial Cells

Background and Objectives: Coronary artery disease (CAD) is the foremost cause of adult disability and mortality. There is an urgent need to focus on the research of new approaches for the prevention and treatment of CAD. Materials and Methods: The effects of peptides isolated from the blood plasma of CAD patients on endothelial cell secretion using the in vitro model have been tested. Human endothelial progenitor cells (HEPCs) were incubated for 24 h with peptides isolated from the plasma of healthy subjects or patients with stable angina, progressive unstable angina, and myocardial infarction. The contents of some soluble anticoagulant as well as procoagulant mediators in HEPC culture treated with peptide pools were then compared. Results and Conclusion: The results show that peptides from the plasma of patients with myocardial infarction promote endothelial cells to release both von Willebrand factor and endothelin-1, increasing vasoconstriction and shifting hemostatic balance toward a prothrombotic state. In contrast, peptides from the plasma of patients with progressive unstable angina suppress the secretion of endothelin-1 by HEPCs, while the secretion of both von Willebrand factor and tissue plasminogen activator was increased. As can be seen from the results obtained, disease derived peptides may contribute to the homeostasis of living organisms or the progression of pathological processes.

Plasminogen Activator Inhibitor-1 4G/5G (rs1799889) Polymorphism in Chinese Patients with Diabetes Mellitus and Hypertension

Objective

To determine the plasminogen activator inhibitor-1 (PAI-1) 4G/5G (rs1799889) genotype of the subjects in a robust detection method and to explore the association of the PAI-1 4G/5G polymorphism with susceptibility to diabetes mellitus (DM) and hypertension (HTN) as well as clinical characteristics.

Methods

This study recruited 208 patients (68 patients were diagnosed with DM, 70 patients with HTN and 70 patients with DM combined with HTN) and 132 healthy controls (HC). A subset of the population was selected to evaluate the accuracy of the Real-time PCR (RT-PCR) method for detecting PAI-1 4G/5G polymorphism by using the sequencing method as the gold standard. Furthermore, the association of the PAI-1 4G/5G polymorphism with genetic susceptibility to DM and HTN was explored. Moreover, variations in clinical characteristics among individuals with various PAI-1 genotypes were also analyzed in the DM group, the HTN group and the DM+HTN group.

Results

There was a high concordance between the RT-PCR method and the sequencing method in determining the PAI-1 4G/5G polymorphism. No association was observed between the PAI-1 4G/5G polymorphism and susceptibility to DM, HTN and DM+HTN, respectively. There were no statistical differences in all study indicators among individuals that carrying various genotypes in the HC group. There were several variations in clinical characteristics among individuals harboring different PAI-1 4G/5G genotypes in the DM group, the HTN group and the DM+HTN group.

Conclusion

The RT-PCR method can accurately identify the PAI-1 4G/5G genotype in different individuals. The PAI-1 4G/5G polymorphism may not be associated with genetic susceptibility to DM, HTN and DM+HTN, but differences in clinical characteristics among individuals with various genotypes may provide a reference for disease assessment and personalized treatment of patients.

Circadian rhythm of plasminogen activator inhibitor-1 and cardiovascular complications in type 2 diabetes

Cardiovascular complications are a common death cause in type 2 diabetes patients, as they are often combined. Plasminogen-activator Inhibitor 1 (PAI-1) participates in the development and progression of cardiovascular complications in diabetes. Insulin resistance increases PAI-1 production, and high PAI-1 levels lead to an environment conducive to thrombosis and earlier and more severe vascular disease. Current evidence also suggests that PAI-1 has a rhythmic profile of circadian fluctuations and acrophase in the morning within a single day, which might explain the high morning incidence of cardiovascular events. Thus, PAI-1 is a possible drug target. Although several PAI-1 inhibitors have been developed, none have yet been allowed for clinical use. Research on rhythm has also led to the concept of "chronotherapy", a rhythm-based drug regimen expected to improve the treatment of cardiovascular complications in diabetic patients. Herein, we searched several databases and reviewed relevant articles to describe the circadian rhythm characteristics and endogenous molecular mechanisms of PAI-1, its relationship with insulin resistance, the causes of cardiovascular complications caused by PAI-1, and the current development of PAI-1 inhibitors. We also summarized the possibility of using the circadian rhythm of PAI-1 to treat cardiovascular complications in diabetic patients.

Plasminogen activator inhibitor-1 levels as an indicator of severity and mortality for COVID-19

OBJECTIVE

Coronavirus disease-19 (COVID-19) is a multisystemic disease that can cause severe illness and mortality by exacerbating symptoms such as thrombosis, fibrinolysis, and inflammation. Plasminogen activator inhibitor-1 (PAI-1) plays an important role in regulating fibrinolysis and may cause thrombotic events to develop. The goal of this study is to examine the relationship between PAI-1 levels and disease severity and mortality in relation to COVID-19.

METHODS

A total of 71 hospitalized patients were diagnosed with COVID-19 using real time-polymerase chain reaction tests. Each patient underwent chest computerized tomography (CT). Data from an additional 20 volunteers without COVID-19 were included in this single-center study. Each patient's PAI-1 data were collected at admission, and the CT severity score (CT-SS) was then calculated for each patient.

RESULTS

The patients were categorized into the control group (n=20), the survivor group (n=47), and the non-survivor group (n=24). In the non-survivor group, the mean age was 75.3±13.8, which is higher than in the survivor group (61.7±16.9) and in the control group (59.5±11.2), (p=0.001). When the PAI-1 levels were compared between each group, the non-survivor group showed the highest levels, followed by the survivor group and then the control group (p<0.001). Logistic regression analysis revealed that age, PAI-1, and disease severity independently predicted COVID-19 mortality rates. In this study, it was observed that PAI-1 levels with >10.2 ng/mL had 83% sensitivity and an 83% specificity rate when used to predict mortality after COVID-19. Then, patients were divided into severe (n=33) and non-severe (n=38) groups according to disease severity levels. The PAI-1 levels found were higher in the severe group (p<0.001) than in the non-severe group. In the regression analysis that followed, high sensitive troponin I and PAI-1 were found to indicate disease severity levels. The CT-SS was estimated as significantly higher in the non-survivor group compared to the survivor group (p<0.001). When comparing CT-SS between the severe group and the non-severe group, this was significantly higher in the severe group (p<0.001). In addition, a strong statistically significant positive correlation was found between CT-SS and PAI-1 levels (r: 0.838, p<0.001).

CONCLUSION

Anticipating poor clinical outcomes in relation to COVID-19 is crucial. This study showed that PAI-1 levels could independently predict disease severity and mortality rates for patients with COVID-19.

Gene Expression Profiling of Markers of Inflammation, Angiogenesis, Coagulation and Fibrinolysis in Patients with Coronary Artery Disease with Very High Lipoprotein(a) Levels Treated with PCSK9 Inhibitors

Besides lipids, inflammation, angiogenesis, coagulation and fibrinolysis play very important roles in coronary artery disease (CAD). We measured gene expression of the inflammatory markers interleukin (IL)-1β (IL1B) and interferon (IFN)-γ (IFNG), vascular endothelial growth factor-A (VEGF-A) (VEGFA), and coagulation and fibrinolysis markers tissue factor (TF) (F3) and plasminogen activator inhibitor-1 (PAI-1) (SERPINE) in healthy controls and CAD patients with high lipoprotein(a) (Lp(a)). The aim of our study was to identify, first, if there is a difference in these markers between controls and patients; secondly, if these markers are associated with lipids; and third, what the influence of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors is on these markers. We included 124 subjects, 27 controls and 97 patients with CAD (30 in placebo and 67 in the PCSK9 group). Blood samples were collected for lipid and gene measurement. The results showed higher expression of IL1B (p < 0.0001), VEGFA (p < 0.0001), and F3 (p = 0.018) in controls in comparison with patients. Significant correlations were observed between IL1B and lipids. Treatment with PCSK9 inhibitors increased VEGFA (p < 0.0001) and F3 (p = 0.001), and decreased SERPINE (p = 0.043). The results of our study underpin the importance of IL-1β, VEGF-A and TF in CAD as well as the effect of PCSK9 treatment on these markers.

PAI-1: A Major Player in the Vascular Dysfunction in Obstructive Sleep Apnea?

Obstructive sleep apnea is a chronic and prevalent condition that is associated with endothelial dysfunction, atherosclerosis, and imposes excess overall cardiovascular risk and mortality. Despite its high prevalence and the susceptibility of CVD patients to OSA-mediated stressors, OSA is still under-recognized and untreated in cardiovascular practice. Moreover, conventional OSA treatments have yielded either controversial or disappointing results in terms of protection against CVD, prompting the need for the identification of additional mechanisms and associated adjuvant therapies. Plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor of tissue-type plasminogen activator (tPA) and urinary-type plasminogen activator (uPA), is a key regulator of fibrinolysis and cell migration. Indeed, elevated PAI-1 expression is associated with major cardiovascular adverse events that have been attributed to its antifibrinolytic activity. However, extensive evidence indicates that PAI-1 can induce endothelial dysfunction and atherosclerosis through complex interactions within the vasculature in an antifibrinolytic-independent matter. Elevated PAI-1 levels have been reported in OSA patients. However, the impact of PAI-1 on OSA-induced CVD has not been addressed to date. Here, we provide a comprehensive review on the mechanisms by which OSA and its most detrimental perturbation, intermittent hypoxia (IH), can enhance the transcription of PAI-1. We also propose causal pathways by which PAI-1 can promote atherosclerosis in OSA, thereby identifying PAI-1 as a potential therapeutic target in OSA-induced CVD.

Effect of PCSK9 Inhibitors on Hemostasis in Patients with Isolated Hypercholesterolemia

Background: In addition to reducing plasma lipids, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors may produce numerous nonlipid-related pleiotropic effects. The purpose of this trial was to determine the efficacy of PCSK9 inhibitors alone in patients with isolated hypercholesterolemia. Methods: The trial enrolled 21 individuals with isolated hypercholesterolemia and atherosclerosis who received alirocumab for 90 days (150 mg every two weeks). Lipids, glucose homeostasis factors, and hemostatic markers were measured in the plasma at baseline and after treatment. Results: The PCSK9 inhibitor administered to these patients reduced plasma levels/activity of fibrinogen (from 3.6 ± 0.5 to 2.9 ± 0.4 g/L, p < 0.01), factor VII (from 143.8 ± 16.7 to 114.5 ± 14.1%, p < 0.01) and plasminogen activator inhibitor-1 (PAI-1) (from 74.9 ± 13.9 to 52.8 ± 9.1 ng/mL, p < 0.001) without a significant reduction in von Willebrand factor levels, and it tended to prolong the partial thromboplastin and prothrombin times. Conclusion: Our findings indicate that treatment with PCSK9 inhibitors has a multipotential effect on fibrinolysis and coagulation in patients with isolated hypercholesterolemia and that this medication may have some future benefits in patients who are statin-intolerant or contraindicated to statin use.

Association of PAI-1 4G/5G and ACE I/D Polymorphisms with Susceptibility to Pediatric Sepsis: Evidence from a Meta-Analysis

BackgroundSeveral studies have investigated the role of PAI-1 4G/5G and ACE I/D polymorphisms in the etiology of pediatric sepsis, but the results are inconsistent. We performed a meta-analysis to assess for any associations. Methods: A comprehensive literature search on PubMed, web of science, and CNKI database was conducted up to April 15, 2020. Results: There were twelve case-control studies involving seven studies with 860 cases and 1144 controls on PA-1 4G/5G and five studies with 1602 cases and 1585 controls on ACE I/D. PAI-1 4G/5G and ACE I/D polymorphisms were associated with an increased risk of pediatric sepsis in the global population. Stratified analysis by ethnicity showed a significant association in the Caucasians children. Conclusions: The meta-analysis suggests that the PAI-1 4G/5G and ACE I/D polymorphisms may be risk factors for development of pediatric sepsis in the global population.

Ligand-mediated PAI-1 inhibition in a mouse model of peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) present a ubiquitous clinical conundrum in all intra-abdominal malignancies. Via functional and transcriptomic experiments of ascites-treated PC cells, we identify STAT3 as a key signaling pathway. Integrative analysis of publicly available databases and correlation with clinical cohorts (n = 7,359) reveal putative clinically significant activating ligands of STAT3 signaling. We further validate a 3-biomarker prognostic panel in ascites independent of clinical covariates in a prospective study (n = 149). Via single-cell sequencing experiments, we uncover that PAI-1, a key component of the prognostic biomarker panel, is largely secreted by fibroblasts and mesothelial cells. Molecular stratification of ascites using PAI-1 levels and STAT3 activation in ascites-treated cells highlight a therapeutic opportunity based on a phenomenon of paracrine addiction. These results are recapitulated in patient-derived ascites-dependent xenografts. Here, we demonstrate therapeutic proof of concept of direct ligand inhibition of a prognostic target within an enclosed biological space.

Sustained postoperative plasma elevations of plasminogen activator inhibitor-1 following minimally invasive colorectal cancer resection

Plasminogen activator inhibitor-1 (PAI-1) is a serine protease inhibitor that inhibits urokinase-type plasminogen activator and tissue-type plasminogen activator. PAI-1 participates in angiogenesis, wound healing and tumor invasion, and additionally regulates endothelial cell proliferation, angiogenesis and tumor growth. The purpose of the present study was to measure plasma PAI-1 levels perioperatively in patients with colorectal cancer (CRC) undergoing minimally invasive colorectal resection (MICR). Patients with CRC who underwent elective MICR were eligible for the study. All patients were enrolled in an approved data/plasma bank. Patients with preoperative, postoperative day (POD) 1, POD 3, and at least one POD 7-34 plasma sample collection were studied. Plasma PAI-1 levels were determined in duplicate using ELISA, and the medians and 95% confidence intervals (CIs) were determined. The correlations between postoperative plasma PAI-1 levels and length of surgery were evaluated. PAI-1 levels were compared between patients who underwent laparoscopic-assisted vs. hand-assisted surgery. The preoperative PAI-1 levels of stage I, II, III and IV pathological stage subgroups were also compared. A total of 91 patients undergoing MICR for CRC were studied. The mean incision length was 8.0±3.9 cm, and the length of stay was 6.8±4.3 days. Compared with the median preoperative levels (17.30; 95% CI: 15.63-19.78 ng/ml), significantly elevated median levels were observed on POD 1 (28.86; 95% CI: 25.46-31.22 ng/ml; P<0.001), POD 3 (18.87; 95% CI: 17.05-21.78 ng/ml; P=0.0037), POD 7-13 (26.97; 95% CI: 22.81-28.74 ng/ml; P<0.001), POD 14-20 (25.92; 95% CI: 17.85-35.89 ng/ml; P=0.001) and POD 21-27 (22.63; 95% CI: 20.03-30.09 ng/ml; P<0.001). The PAI-1 levels in the hand-assisted group were higher compared with those in the laparoscopic-assisted group for 4 weeks after surgery; however, a significant difference was found only on POD 1. Therefore, plasma PIA-1 levels were found to be significantly elevated for 4 weeks after MICR, and the surgery-related acute inflammatory response may account for the early postoperative PIA-1 increase. Furthermore, PAI-1-associated VEGF-induced angiogenesis in the healing wounds may account for the late postoperative elevations, and increased PAI-1 levels may promote angiogenesis in residual tumor deposits.

Pathomechanisms Underlying Hypoxemia in Two COVID-19-Associated Acute Respiratory Distress Syndrome Phenotypes: Insights From Thrombosis and Hemostasis

BACKGROUND

The pathomechanisms of hypoxemia and treatment strategies for type H and type L acute respiratory distress syndrome (ARDS) in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced coronavirus disease 2019 (COVID-19) have not been elucidated.

MAIN TEXT

SARS-CoV-2 mainly targets the lungs and blood, leading to ARDS, and systemic thrombosis or bleeding. Angiotensin II-induced coagulopathy, SARS-CoV-2-induced hyperfibrin(ogen)olysis, and pulmonary and/or disseminated intravascular coagulation due to immunothrombosis contribute to COVID-19-associated coagulopathy. Type H ARDS is associated with hypoxemia due to diffuse alveolar damage-induced high right-to-left shunts. Immunothrombosis occurs at the site of infection due to innate immune inflammatory and coagulofibrinolytic responses to SARS-CoV-2, resulting in microvascular occlusion with hypoperfusion of the lungs. Lung immunothrombosis in type L ARDS results from neutrophil extracellular traps containing platelets and fibrin in the lung microvasculature, leading to hypoxemia due to impaired blood flow and a high ventilation/perfusion (VA/Q) ratio. COVID-19-associated ARDS is more vascular centric than the other types of ARDS. D-dimer levels have been monitored for the progression of microvascular thrombosis in COVID-19 patients. Early anticoagulation therapy in critical patients with high D-dimer levels may improve prognosis, including the prevention and/or alleviation of ARDS.

CONCLUSIONS

Right-to-left shunts and high VA/Q ratios caused by lung microvascular thrombosis contribute to hypoxemia in type H and L ARDS, respectively. D-dimer monitoring-based anticoagulation therapy may prevent the progression to and/or worsening of ARDS in COVID-19 patients.

Effect of sera from lupus patients on the glomerular endothelial fibrinolysis system

BACKGROUND

Dysregulation of the coagulation fibrinolysis system in resident glomerular cells is associated with the pathogenesis of lupus nephritis. However, the role of plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA) in resident glomerular cells remains undetermined.

METHODS

We examined the expression of PAI-1 and tPA mRNA in cultured normal human glomerular endothelial cells (GECs) treated with serum from patients with systemic lupus erythematosus (SLE) using quantitative reverse transcription polymerase chain reactions. We determined the relationship between PAI-1/tPA mRNA expression and several clinical/laboratory parameters. Serum from 16 patients (nine patients with new-onset SLE and seven patients with stable SLE) was used in the study.

RESULTS

Plasminogen activator inhibitor-1 and tPA mRNA expression was significantly higher in GECs treated with serum of patients with new-onset SLE than other groups. The PAI-1 and tPA mRNA levels were also significantly correlated in GECs treated with serum from patients with SLE. Interestingly, both PAI-1 and tPA mRNA levels in GECs were inversely correlated with serum C4 level and positively correlated with SLE disease activity.

CONCLUSIONS

These results suggest that serum from patients with SLE may activate the fibrinolysis system in glomerulus, which may be involved in the pathogenesis of lupus nephritis.

Role of Macrophages and Plasminogen Activator Inhibitor-1 in Delayed Bone Repair Induced by Glucocorticoids in Mice

Glucocorticoids delay fracture healing and induce osteoporosis. However, the mechanisms by which glucocorticoids delay bone repair have yet to be clarified. Plasminogen activator inhibitor-1 (PAI-1) is the principal inhibitor of plasminogen activators and an adipocytokine that regulates metabolism. We herein investigated the roles of macrophages in glucocorticoid-induced delays in bone repair after femoral bone injury using PAI-1-deficient female mice intraperitoneally administered with dexamethasone (Dex). Dex significantly decreased the number of F4/80-positive macrophages at the damaged site two days after femoral bone injury. It also attenuated bone injury-induced decreases in the number of hematopoietic stem cells in bone marrow in wild-type and PAI-1-deficient mice. PAI-1 deficiency significantly weakened Dex-induced decreases in macrophage number and macrophage colony-stimulating factor (M-CSF) mRNA levels at the damaged site two days after bone injury. It also significantly ameliorated the Dex-induced inhibition of macrophage phagocytosis at the damaged site. In conclusion, we herein demonstrated that Dex decreased the number of macrophages at the damaged site during early bone repair after femoral bone injury partly through PAI-1 and M-CSF in mice.

Association of Polymorphisms in Plasminogen Activator Inhibitor-1 (PAI-1), Tissue Plasminogen Activator (tPA), and Renin (REN) with Recurrent Pregnancy Loss in Korean Women

Recurrent pregnancy loss (RPL) is defined as two or more consecutive pregnancy losses prior to 20 weeks of gestational age. Various factors, including immune dysfunction, endocrine disorders, coagulation abnormality, and genetic disorders influence RPL. In particular, plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA), and renin (REN) have important roles in the thrombotic and thrombolytic systems, and abnormal expression of these genes have a reported negative correlation with pregnancy maintenance. Moreover, some polymorphisms of the three genes are related to expression levels and thrombotic disorder. Therefore, we investigated whether polymorphisms of PAI-1, tPA, and REN are linked to RPL. Genotyping of the six polymorphisms (PAI-1 rs11178, rs1050955, tPA rs4646972, rs2020918, REN rs1464816, and rs5707) was performed using polymerase chain reaction (PCR)-restriction fragment length polymorphism and associations of the polymorphisms with RPL were evaluated by statistical analysis. The polymorphism PAI-1 rs1050955 GA+AA was associated with decreased RPL risk (AOR, 0.528; 95% CI 0.356–0.781; p = 0.001) as was the REN 10795 rs5707 GG genotype (AOR, 0.487; 95% CI 0.301–0.787; p = 0.003). In contrast, the tPA rs4646972 II genotype correlated with increased RPL risk (AOR, 1.606; 95% CI, 1.047–2.463; p = 0.030). This study provides evidence that tPA Alu rs4646972 may contribute to the risk of idiopathic RPL, but PAI-1 12068 rs1050955 and REN 10795 rs5707 are associated with a decreased risk of RPL. Therefore, these alleles may be useful as biomarkers to evaluate the risk of RPL.

Association of the Circulating Supar Levels with Inflammation, Fibrinolysis, and Outcome in Severe Burn Patients

BACKGROUND

Hyperfibrinolysis and pro/anti-inflammatory imbalance usually occur in the early stage of severe burns. Soluble urokinase-type plasminogen activator receptor (suPAR) is involved in fibrinolysis and inflammation. To date, the levels of circulating suPAR in non-survivors with severe burns remain unknown. This study aimed to investigate the early association between circulating suPAR levels and biomarkers of fibrinolysis, pro/anti-inflammatory, and prognosis.

METHODS

Sixty-four consecutive Chinese patients with severe burns and 26 healthy volunteers were enrolled in a prospective observational cohort. Clinical characteristics and laboratory data were collected prospectively. Blood samples were collected at 48 h post-burn, and suPAR and biomarkers of pro/anti-inflammatory and fibrinolysis were detected by enzyme-linked immunosorbent assays. Important indicators between non-survivors and survivors were compared. Linear regression analysis was performed to screen variables associated with suPAR. Logistic regression analysis and receiver operating characteristic curve (ROC) analysis were performed to evaluate the prognostic value of suPAR.

RESULT

Compared with the control group, the circulating suPAR levels in the survivors (P < 0.001) and non-survivors (P = 0.017) were higher. Compared with survivors, non-survivors had lower circulating suPAR levels at 48 h post-burn, and they showed a higher degree of fibrinolysis (higher D-dimer) and a lower TNF-α/IL-10 ratio. According to linear regression analysis, the variables independently associated with a lower suPAR level were lower platelet factor 4 (PF-4), urokinase-type plasminogen activator (uPA), and TNF-α/IL-10 levels and a higher D-dimer level. Logistic regression and ROC analyses indicated that a suPAR level ≤ 4.70 μg/L was independently associated with 30-day mortality.

CONCLUSION

Low circulating suPAR levels at 48 h post-burn in severe burn patients may reflect decreased TNF-α/IL-10 ratio and increased hyperfibrinolysis. suPAR can predict 30-day mortality in patients with severe burn.

Endothelial dysfunction and COVID-19 (Review)

It is hypothesized that several comorbidities increase the severity of COVID-19 symptoms. Cardiovascular disease including hypertension was shown to play a critical role in the severity of COVID-19 infection by affecting the survival of patients with COVID-19. Hypertension and the renin-angiotensin-aldosterone system are involved in increasing vascular inflammation and endothelial dysfunction (ED), and both processes are instrumental in COVID-19. Angiotensin-converting enzyme 2 is an essential component of the renin-angiotensin-aldosterone system and the target receptor that mediates SARS-CoV-2 entry to the cell. This led to speculations that major renin-angiotensin-aldosterone system inhibitors, such as angiotensin receptor blockers and angiotensin-converting enzyme inhibitors might affect the course of the disease, since their administration enhances angiotensin-converting enzyme (ACE)2 expression. An increase in ACE2 activity could reduce angiotensin II concentration in the lungs and mitigate virus-driven lung injury. This could also be associated with a reduction in blood coagulation, which plays a critical role in the pathogenesis of SARS-CoV-2; of note, COVID-19 is now regarded as a disorder of blood clotting. Therefore, there is an urgent need to better understand the effect of targeting ACE2 as a potential treatment for SARS-CoV-2 driven injury, and in alleviating COVID-19 symptoms by reversing SARS-CoV-2-induced excessive coagulation and fatalities. Ongoing therapeutic strategies that include recombinant human ACE2 and anti-spike monoclonal antibodies are essential for future clinical practice in order to better understand the effect of targeting ED in COVID-19.

Fibrin-mediated growth restriction of early-stage human trophoblasts is switched to growth promotion through fibrinolysis

STUDY QUESTION

Does fibrin promote trophoblast growth in human and mouse blastocysts during early embryo implantation?

SUMMARY ANSWER

Mouse blastocysts were unaffected by fibrin; however, human blastocysts were significantly suppressed by fibrin in trophoblast growth and then switched to growth promotion through increased fibrinolysis with urokinase-type plasminogen activator (uPA) activity.

WHAT IS KNOWN ALREADY

Fibrin(ogen) plays an important role in various physiological processes and is also critical for maintaining feto-maternal attachment during pregnancy. The addition of fibrin to embryo transfer media has been used to increase implantation rates in human ART; however, its mechanism of action' in vitro has not yet been characterized.

STUDY DESIGN, SIZE, DURATION

Vitrified mouse and human blastocysts were warmed and individually cultured in vitro for up to 120 and 168 h, respectively, on a fibrin substrate. Blastocysts were cultured at 37°C in 6% CO2, 5% O2 and 89% N2. Blastocyst development and related fibrinolytic factors were analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

ICR strain mouse embryos were purchased from a commercial supplier. Human blastocysts were donated with informed consent from two fertility centers. Mouse and human blastocysts cultured on fibrin-coated plates were compared to those on non-coated and collagen-coated plates in vitro. Trophoblast growth and fibrin degradation were assessed based on the cell area and fibrin-free area, respectively. Fibrinolytic factors were detected in supernatants using plasminogen-casein zymography. The fibrinolytic activity of blastocysts was investigated using a selective uPA inhibitor, exogenous uPA, plasminogen activator inhibitor-1 (PAI-1) inhibitor and fibrin degradation products (FDPs). Fibrinolysis-related mRNA expression level was detected using quantitative real-time PCR.

MAIN RESULTS AND THE ROLE OF CHANCE

Fibrin did not affect the developmental speed or morphology of mouse blastocysts, and a large fibrin-degrading region was observed in the attachment stage. In contrast, fibrin significantly suppressed the outgrowth of trophoblasts in human blastocysts, and trophoblasts grew after the appearance of small fibrin-degrading regions. uPA was identified as a fibrinolytic factor in the conditioned medium, and uPA activity was significantly weaker in human blastocysts than in mouse blastocysts. The inhibition of uPA significantly reduced the outgrowth of trophoblasts in mouse and human blastocysts. Human blastocysts expressed PLAU (uPA), PLAUR (uPA receptor), SERPINE1 (PAI-1) and SERPINB2 (PAI-2), whereas mouse blastocysts were limited to Plau, Plaur and Serpine1. In a subsequent experiment on human blastocysts, the addition of exogenous uPA and the PAI-1 inhibitor promoted trophoblast growth in the presence of fibrin, as did the addition of FDPs.

LIMITATIONS, REASONS FOR CAUTION

This model excludes maternal factors and may not be fully reproduced in vivo. Donated human embryos are surplus embryos that may inherently exhibit reduced embryonic development. In addition, donated ART-derived embryos may exhibit weak uPA activity, because women with sufficient uPA-active embryos may not originally require ART. The present study used orthodox culture methods, and results may change with the application of recently developed protocols for culture blastocysts beyond the implantation stage.

WIDER IMPLICATIONS OF THE FINDINGS

The present results suggest that the distinct features of trophoblast outgrowth in human blastocysts observed in the presence of fibrin are regulated by a phenotypic conversion induced by contact with fibrin and FDPs. Mouse embryos did not exhibit the human phenomenon, indicating that the present results may be limited to humans.

STUDY FUNDING/COMPETING INTEREST(S)

The present study was supported by the Department of Obstetrics and Gynecology at the Hamamatsu University School of Medicine and Kishokai Medical Corporation. None of the authors have any conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Thrombo-inflammatory biomarkers to predict sepsis outcome

Background: Sepsis has been redefined recently as life-threatening organ dysfunction caused by dysregulated host responses to infection and septic shock. Soluble urokinase plasminogen activator receptor (SuPAR) and plasminogen activator inhibitor-1(PAI-1) concentration positively correlate to the activation level of the immune system, and are markers of disease severity and aggressiveness. Objective: The study aimed to identify the blood level of plasminogen activator inhibitor-1 (PAI-1) and soluble urokinase plasminogen activator receptor (SuPAR) in sepsis and its association with mortality. Patient and methods: This is an observational prospective study that enrolled 60 adult patients with sepsis (according to SOFA), admitted to Menoufia and Zagazig university hospitals during the period from December 2019 till October 2020. Plasminogen activator inhibitor-1 (PAI-1) and soluble urokinase plasminogen activator receptor (SuPAR) were checked in all participants. Results: SuPAR and PAI.1 were significant independent predictors of hospital mortality. SuPAR showed sensitivity 100%, specificity 95.9%, and accuracy 94% for prediction of early mortality at a cutoff value of 13.4(pg/ml). While, PAI-1 demonstrated sensitivity 100%, specificity 93.9%, and accuracy of 95% at a cutoff value of 122.5 for predicting mortality. Conclusion: PAI-1 and suPAR were significant predictors of hospital mortality among sepsis patients. The sample size was relatively small, which may have decreased the statistical power of the results of the present study. Hence, additional studies with large sample sizes are required for further validation of the present results.

GYY4137 Regulates Extracellular Matrix Turnover in the Diabetic Kidney by Modulating Retinoid X Receptor Signaling

Diabetic kidney is associated with an accumulation of extracellular matrix (ECM) leading to renal fibrosis. Dysregulation of retinoic acid metabolism involving retinoic acid receptors (RARs) and retinoid X receptors (RXRs) has been shown to play a crucial role in diabetic nephropathy (DN). Furthermore, RARs and peroxisome proliferator-activated receptor γ (PPARγ) are known to control the RXR-mediated transcriptional regulation of several target genes involved in DN. Recently, RAR and RXR have been shown to upregulate plasminogen activator inhibitor-1 (PAI-1), a major player involved in ECM accumulation and renal fibrosis during DN. Interestingly, hydrogen sulfide (H₂S) has been shown to ameliorate adverse renal remodeling in DN. We investigated the role of RXR signaling in the ECM turnover in diabetic kidney, and whether H₂S can mitigate ECM accumulation by modulating PPAR/RAR-mediated RXR signaling. We used wild-type (C57BL/6J), diabetic (C57BL/6-Ins2^Akita/J) mice and mouse mesangial cells (MCs) as experimental models. GYY4137 was used as a H₂S donor. Results showed that in diabetic kidney, the expression of PPARγ was decreased, whereas upregulations of RXRα, RXRβ, and RARγ1 expression were observed. The changes were associated with elevated PAI-1, MMP-9 and MMP-13. In addition, the expressions of collagen IV, fibronectin and laminin were increased, whereas elastin expression was decreased in the diabetic kidney. Excessive collagen deposition was observed predominantly in the peri-glomerular and glomerular regions of the diabetic kidney. Immunohistochemical localization revealed elevated expression of fibronectin and laminin in the glomeruli of the diabetic kidney. GYY4137 reversed the pathological changes. Similar results were observed in in vitro experiments. In conclusion, our data suggest that RXR signaling plays a significant role in ECM turnover, and GYY4137 modulates PPAR/RAR-mediated RXR signaling to ameliorate PAI-1-dependent adverse ECM turnover in DN.

Hypoxia Promotes a Mixed Inflammatory-Fibrotic Macrophages Phenotype in Active Sarcoidosis

Background

Macrophages are pivotal cells in sarcoidosis. Monocytes-derived (MD) macrophages have recently been demonstrated to play a major role especially in pulmonary sarcoidosis. From inflammatory tissues to granulomas, they may be exposed to low oxygen tension environments. As hypoxia impact on sarcoidosis immune cells has never been addressed, we designed the present study to investigate MD-macrophages from sarcoidosis patients in this context. We hypothesized that hypoxia may induce functional changes on MD-macrophages which could have a potential impact on the course of sarcoidosis.

Methods

We studied MD-macrophages, from high active sarcoidosis (AS) (n=26), low active or inactive sarcoidosis (IS) (n=24) and healthy controls (n=34) exposed 24 hours to normoxia (21% O₂) or hypoxia (1.5% O₂). Different macrophage functions were explored: hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-kappa B (NF-κB) activation, cytokines secretion, phagocytosis, CD80/CD86/HLA-DR expression, profibrotic response.

Results

We observed that hypoxia, with a significantly more pronounced effect in AS compared with controls and IS, increased the HIF-1α trans-activity, promoted a proinflammatory response (TNFα, IL1ß) without activating NF-κB pathway and a profibrotic response (TGFß1, PDGF-BB) with PAI-1 secretion associated with human lung fibroblast migration inhibition. These results were confirmed by immunodetection of HIF-1α and PAI-1 in granulomas observed in pulmonary biopsies from patients with sarcoidosis. Hypoxia also decreased the expression of CD80/CD86 and HLA-DR on MD-macrophages in the three groups while it did not impair phagocytosis and the expression of CD36 expression on cells in AS and IS at variance with controls.

Conclusions

Hypoxia had a significant impact on MD-macrophages from sarcoidosis patients, with the strongest effect seen in patients with high active disease. Therefore, hypoxia could play a significant role in sarcoidosis pathogenesis by increasing the macrophage proinflammatory response, maintaining phagocytosis and reducing antigen presentation, leading to a deficient T cell response. In addition, hypoxia could favor fibrosis by promoting profibrotic cytokines response and by sequestering fibroblasts in the vicinity of granulomas.

Regulation of Plasminogen Activator Inhibitor-1 in Adipocytes by Macrophages Activated by Low-dose Lipopolysaccharide

BACKGROUND/AIM

Increased expression of inflammatory cytokine genes through cell interactions in tissues may cause chronic inflammation, leading to the development of lifestyle-related diseases. Since the activation of inflammatory cytokine genes in monocytes/macrophages by co-culturing with cancer cells or adipocytes was suppressed by pre-treatment with low-dose lipopolysaccharide (LPS), we hypothesized that low-dose LPS-activated macrophages may regulate the expression of immune response-related genes in other cells.

MATERIALS AND METHODS

Phorbol myristate acetate-treated human monocytes (THP-1) were activated by LPS. The conditioned medium of LPS-activated THP-1 cells was added to human adipocytes. After 5 days, the expression of genes encoding interleukin (IL)-6 (IL6), IL-8 (IL8), monocyte chemotactic protein (MCP)-1 (CCL2), adiponectin (ADIPOQ), and plasminogen activator inhibitor (PAI)-1 (SERPINE1) was analyzed using quantitative real-time PCR.

RESULTS

The increased expression of inflammation-related genes and SERPINE1 in adipocytes was suppressed by the conditioned medium of THP-1 cells activated by low-dose LPS, whereas the expression of ADIPOQ was significantly increased.

CONCLUSION

Low-dose LPS-activated macrophages convert adipocytes to anti-inflammatory phenotypes.

HDAC Inhibitor Abrogates LTA-Induced PAI-1 Expression in Pleural Mesothelial Cells and Attenuates Experimental Pleural Fibrosis

Lipoteichoic acid (LTA) stimulates pleural mesothelial cell (PMC) to overproduce plasminogen activator inhibitor-1 (PAI-1), and thus may promote pleural fibrosis in Gram-positive bacteria (GPB) parapneumonic effusion (PPE). Histone deacetylase inhibitor (HDACi) was found to possess anti-fibrotic properties. However, the effects of HDACi on pleural fibrosis remain unclear. The effusion PAI-1 was measured among 64 patients with GPB PPE. Pleural fibrosis was measured as radiographical residual pleural thickening (RPT) and opacity at a 12-month follow-up. The LTA-stimulated human PMCs and intrapleural doxycycline-injected rats were pretreated with or without the pan-HDACi, m-carboxycinnamic acid bis-hydroxamide (CBHA), then PAI-1 and collagen expression and activated signalings in PMCs, and morphologic pleural changes in rats were measured. Effusion PAI-1 levels were significantly higher in GPB PPE patients with RPT > 10 mm (n = 26) than those without (n = 38), and had positive correlation with pleural fibrosis shadowing. CBHA significantly reduced LTA-induced PAI-1 and collagen expression via inhibition of JNK, and decreased PAI-1 promoter activity and mRNA levels in PMCs. Furthermore, in doxycycline-treated rats, CBHA substantially repressed PAI-1 and collagen synthesis in pleural mesothelium and minimized pleural fibrosis. Conclusively, CBHA abrogates LTA-induced PAI-1 and collagen expression in PMCs and attenuates experimental pleural fibrosis. PAI-1 inhibition by HDACi may confer potential therapy for pleural fibrosis.

Hypertriglyceridemic Waist in Patients with Type 2 Diabetes: Its Relationship to Selected Markers of Vascular Damage

Background: To evaluate the association between hypertriglyceridemic waist (HTGW), a promising marker of visceral adiposity and cardiovascular (CV) risk, and different indicators of vascular damage in type 2 diabetes (T2D) patients. Methods: This case-control study included 161 patients with T2D (91 males, 70 females) and 40 healthy controls (24 males, 16 females). HTWG was defined as waist circumference >90 cm in men or >85 cm in women and triglyceride concentrations >2 mmol/L. In addition to anthropometric and metabolic parameters, markers of endothelial dysfunction, namely von Willebrand factor (vWF) and plasminogen activator inhibitor-1 (PAI-1), were assessed. Arterial stiffness parameters were examined using the SphygmoCor system. Results: Individuals with T2D and HTGW showed the highest elevation of PAI-1 levels and significantly increased vWF levels compared with healthy controls. No significant differences in arterial stiffness markers were observed between T2D individuals. Age and, for several markers, systolic and/or diastolic blood pressure were identified as the main predictors for arterial stiffness, whereas PAI-1 and vWF levels were predicted by metabolic parameters. Conclusions: HTGW represents increased CV risk in T2D patients, mainly due to endothelial damage. The presence of HTGW had no significant effect on arterial stiffness compared with other T2D individuals.

A meta-analysis of the association of the ACE I/D and PAI-1 4G/5G polymorphisms with recurrent pregnancy loss in Iranian women: Are the investigations adequate?

The associations of ACE I/D and PAI-1 4G/5G polymorphisms with recurrent pregnancy loss (RPL) in Iranian women have yielded controversial results. Thus, we conducted a meta-analysis to obtain more certain results. A comprehensive literature search was performed in the PubMed, Web of Sciences, Scopus, MedRxiv, SID, and CNKI databases up to January 1st, 2021, using the appropriate terms. All case-control studies were included. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the strength of associations. A total of 14 studies including eight studies with 783 patients and 761 healthy subjects on ACE I/D and six studies with 1.155 patients and 699 healthy subjects on PAI-1 4G/5G were included. Combined data revealed that ACE I/D polymorphism was significantly associated with RPL risk in Iranian women under three models i.e., allele [OR=0.744, 95% CI: (0.640-0.864); p≤0.001], dominant [OR=0.774, 95% CI: (0.601-0.996); p=0.047], and recessive [OR=0.767, 95% CI: (0.611-0.963); p=0.022]. Moreover, the pooled data showed a significant association between the PAI-1 4G/5G polymorphism and RPL risk under all five models i.e., allele [OR=2.352, 95% CI: (1.623-3.408); p≤0.001], heterozygote [OR=8.364, 95% CI: (4.744-14.756); p≤0.001), homozygote [OR=2.192, 95% CI: (1.093-4.394); p=0.027), dominant [OR=2.354, 95% CI: (1.309-4.235); p=0.004], and recessive [OR=5.208, 95% CI: (3.005-9.025); p≤0.001]. Stratification analysis revealed that these polymorphisms were associated with RPL risk by the number of miscarriages. Our pooled data indicated that ACE I/D and PAI-1 4G/5G polymorphisms were significantly associated with an increased risk of RPL in Iranian women. These significant findings showed that the investigation might be adequate for ACE I/D and PAI-1 4G/5G polymorphisms in the Iranian population.

Precision targeting of the plasminogen activator inhibitor-1 mechanism increases efficacy of fibrinolytic therapy in empyema

Plasminogen activator inhibitor‐1 (PAI‐1) is an endogenous irreversible inhibitor of tissue‐type (tPA) and urokinase (uPA) plasminogen activators. PAI‐1‐targeted fibrinolytic therapy (PAI‐1‐TFT) is designed to decrease the therapeutic dose of tPA and uPA, attenuating the risk of bleeding and other complications. Docking site peptide (DSP) mimics the part of the PAI‐1 reactive center loop that interacts with plasminogen activators, thereby affecting the PAI‐1 mechanism. We used DSP for PAI‐1‐TFT in two rabbit models: chemically induced pleural injury and Streptococcus pneumoniae induced empyema. These models feature different levels of inflammation and PAI‐1 expression. PAI‐1‐TFT with DSP (2.0 mg/kg) converted ineffective doses of single chain (sc) tPA (72.5 µg/kg) and scuPA (62.5 µg/kg) into effective ones in chemically induced pleural injury. DSP (2.0 mg/kg) was ineffective in S. pneumoniae empyema, where the level of PAI‐1 is an order of magnitude higher. DSP dose escalation to 8.0 mg/kg resulted in effective PAI‐1‐TFT with 0.25 mg/kg sctPA (1/8th of the effective dose of sctPA alone) in empyema. There was no increase in the efficacy of scuPA. PAI‐1‐TFT with DSP increases the efficacy of fibrinolytic therapy up to 8‐fold in chemically induced (sctPA and scuPA) and infectious (sctPA) pleural injury in rabbits. PAI‐1 is a valid molecular target in our model of S. pneumoniae empyema in rabbits, which closely recapitulates key characteristics of empyema in humans. Low‐dose PAI‐1‐TFT is a novel interventional strategy that offers the potential to improve fibrinolytic therapy for empyema in clinical practice.

Annexin A2-Mediated Plasminogen Activation in Endothelial Cells Contributes to the Proangiogenic Effect of Adenosine A2A Receptors

Adenosine A_2A receptor mediates the promotion of wound healing and revascularization of injured tissue, in healthy and animals with impaired wound healing, through a mechanism depending upon tissue plasminogen activator (tPA), a component of the fibrinolytic system. In order to evaluate the contribution of plasmin generation in the proangiogenic effect of adenosine A_2A receptor activation, we determined the expression and secretion of t-PA, urokinase plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1) and annexin A2 by human dermal microvascular endothelial cells stimulated by the selective agonist CGS-21680. The plasmin generation was assayed through an enzymatic assay and the proangiogenic effect was studied using an endothelial tube formation assay in Matrigel. Adenosine A_2A receptor activation in endothelial cells diminished the release of PAI-1 and promoted the production of annexin A2, which acts as a cell membrane co-receptor for plasminogen and its activator tPA. Annexin A2 mediated the increased cell membrane-associated plasmin generation in adenosine A_2A receptor agonist treated human dermal microvascular endothelial cells and is required for tube formation in an in vitro model of angiogenesis. These results suggest a novel mechanism by which adenosine A_2A receptor activation promotes angiogenesis: increased endothelial expression of annexin A2, which, in turn, promotes fibrinolysis by binding tPA and plasminogen to the cell surface.

Dietary Strawberries Improve Cardiometabolic Risks in Adults with Obesity and Elevated Serum LDL Cholesterol in a Randomized Controlled Crossover Trial

Background and aims: Dietary berries, such as strawberries, are rich in bioactive compounds and have been shown to lower cardiometabolic risk. We examined the effects of two dietary achievable doses of strawberries on glycemic control and lipid profiles in obese adults with elevated serum LDL cholesterol (LDL-C). Methods: In this 14-week randomized controlled crossover study, participants were assigned to one of the three arms for four weeks separated by a one-week washout period: control powder, one serving (low dose: 13 g strawberry powder/day), or two-and-a -half servings (high dose: 32 g strawberry powder/day). Participants were instructed to follow their usual diet and lifestyle while refraining from consuming other berries and related products throughout the study interval. Blood samples, anthropometric measures, blood pressure, and dietary and physical activity data were collected at baseline and at the end of each four-week phase of intervention. Results: In total, 33 participants completed all three phases of the trial [(mean ± SD): Age: 53 ± 13 y; BMI: 33 ± 3.0 kg/m²). Findings revealed significant reductions in fasting insulin (p = 0.0002) and homeostatic model of assessment of insulin resistance (p = 0.0003) following the high dose strawberry phase when compared to the low dose strawberry and control phases. Glucose and conventional lipid profiles did not differ among the phases. Nuclear magnetic resonance-determined particle concentrations of total VLDL and chylomicrons, small VLDL, and total and small LDL were significantly decreased after the high dose strawberry phase, compared to control and low dose phases (all p < 0.0001). Among the biomarkers of inflammation and adipokines measured, only serum PAI-1 showed a decrease after the high dose strawberry phase (p = 0.002). Conclusions: These data suggest that consuming strawberries at two-and-a-half servings for four weeks significantly improves insulin resistance, lipid particle profiles, and serum PAI-1 in obese adults with elevated serum LDL-C.

COVID-19 Associated Hypercoagulability: Manifestations, Mechanisms, and Management

ABSTRACT

Patients with severe coronavirus disease-2019 (COVID-19) frequently have hypercoagulability caused by the immune response to the severe acute respiratory syndrome coronavirus-2 infection. The pathophysiology of COVID-19 associated hypercoagulability is not fully understood, but characteristic changes include: increased fibrinogen concentration, increased Factor VIII activity, increased circulating von Willebrand factor, and exhausted fibrinolysis. Anticoagulant therapy improves outcomes in mechanically ventilated patients with COVID-19 and viscoelastic coagulation testing offers an opportunity to tailor anticoagulant therapy based on an individual patient's coagulation status. In this narrative review, we summarize clinical manifestations of COVID-19, mechanisms, monitoring considerations, and anticoagulant therapy. We also review unique considerations for COVID-19 patients who are on extracorporeal membrane oxygenation.

Hyaluronic Acid Treatment Improves Healing of the Tenorrhaphy Site by Suppressing Adhesions through Extracellular Matrix Remodeling in a Rat Model

Due to the limited supply of vessels and nerves, acute or chronic tendon injuries often result in significant and persistent complications, such as pain and sprains, as well as the loss of joint functions. Among these complications, tendon adhesions within the surrounding soft tissue have been shown to significantly impair the range of motion. In this study, to elucidate the effects of a hyaluronic acid (HA) injection at the site of tenorrhaphy on tendon adhesion formation, we used a full transection model of a rat’s Achilles tendon to investigate the anti-adhesive function of HA. Our initial findings showed that significantly lower adhesion scores were observed in the HA-treated experimental group than in the normal saline-treated control group, as determined by macroscopic and histological evaluations. Hematoxylin and eosin, as well as picrosirius red staining, showed denser and irregular collagen fibers, with the larger number of infiltrating inflammatory cells in the control group indicating severe adhesion formation. Furthermore, we observed that the expression of tendon adhesion markers in operated tendon tissue, such as collagen type I, transforming growth factor-β1, and plasminogen activator inhibitor-1, was suppressed at both the gene and protein levels following HA treatment. These results suggest that HA injections could reduce tendon adhesion formation by significantly ameliorating inflammatory-associated reactions.

Plasminogen Activator Inhibitor-1 Secretion by Autophagy Contributes to Melanoma Resistance to Chemotherapy through Tumor Microenvironment Modulation

Simple Summary

Dysregulation of tumor autophagy is implicated in cancer progression and chemotherapeutic response. It is unclear how tumor autophagy modulates tumor microenvironment and thereby contributes to chemoresistance. In this study, we found that autophagy-dependent plasminogen activator inhibitor (PAI)-1 secretion contributed to melanoma resistance to mitoxantrone (MitoX), a chemotherapeutic agent clinically used for treating various types of cancers (but not melanoma), by shaping a pro-tumoral microenvironment. Disruption of autophagy activity or targeting PAI-1 pharmacologically reshaped a tumor-suppressive immune microenvironment and enhanced the susceptibility of melanoma to MitoX in vivo. Overall, the results show that targeting autophagy/PAI-1 axis can serve as a novel strategy to repurpose MitoX-based chemotherapy.

Abstract

Autophagy plays a crucial role in maintenance of cellular homeostasis via intracellular signaling pathways, lysosomal degradation of selective cargo and mediating protein secretion. Dysregulation of autophagy has been implicated in tumorigenesis, tumor progression, and resistance to therapy. However, the mechanism of autophagy-dependent secretion involved in the responsiveness to chemotherapy is poorly understood. In this study, we showed that mitoxantrone (MitoX), a chemotherapeutic agent used for treating various cancers but not melanoma, induced autophagy in melanoma cells in vitro and in vivo. We also found that plasminogen activator inhibitor (PAI)-1 secretion by MitoX-induced autophagy modulated the pro-tumoral microenvironment. Attenuation of PAI-1 activity using a specific inhibitor, tiplaxtinin (TPX), or by targeting the autophagy gene, Becn1, induced efficient antitumor immunity, thereby overcoming the resistance to MitoX in vivo. Of note, the therapeutic efficacy of TPX was abolished in MitoX-treated Becn1-defective tumors. Collectively, our results demonstrate that tumor autophagy-dependent PAI-1 secretion impairs the therapeutic efficacy of MitoX and highlight targeting of tumor autophagy or its secretory cargo, PAI-1, as a novel strategy to repurpose MitoX-based chemotherapy for melanoma treatment.

Comparison of biomarkers of endothelial dysfunction and microvascular endothelial function in patients with primary aldosteronism and essential hypertension

Introduction:

Studies have shown that primary aldosteronism (PA) has a higher risk of cardiovascular events than essential hypertension (EH). Endothelial dysfunction is an independent predictor of cardiovascular events. Whether PA and EH differ in the endothelial dysfunction is uncertain. Our study was designed to investigate the levels of biomarkers of endothelial dysfunction (Asymmetric dimethylarginine, ADMA; E-selectin, and Plasminogen activator inhibitor-1, PAI-1) and assess the microvascular endothelial function in patients with PA and EH, respectively.

Methods:

The biomarkers of endothelial dysfunction were measured by enzyme-linked immunosorbent assay (ELISA). Microvascular endothelial function was evaluated by Pulse amplitude tonometry (PAT).

Results:

Thirty-one subjects with EH and 36 subjects with PA including 22 with aldosterone-producing adenoma (APA) and 14 with idiopathic hyperaldosteronism (IHA) were enrolled in our study. The ADMA levels among the three groups were different (APA 47.83 (27.50, 87.74) ng/ml vs EH 25.08 (22.44, 39.79) ng/ml vs IHA 26.00 (22.23, 33.75) ng/ml; p = 0.04), however, when the APA group was compared with EH and IHA group, there was no statistical significance (47.83 (27.50, 87.74) ng/ml vs 25.08 (22.44, 39.79) ng/ml for EH, p = 0.11; 47.83 (27.50, 87.74) ng/ml vs IHA 26.00 (33.75) ng/ml, p = 0.07). The results of ADMA levels are presented as Median (p25, p75). Whereas, levels of PAI-1 and E-selectin, microvascular endothelial function were not significantly different between PA and EH subjects.

Conclusions:

Our study shows no significant differences between PA and EH in terms of biomarkers of endothelial dysfunction and microvascular endothelial function. The microvascular endothelial function of PA and EH patients is comparable.

Livedoid vasculopathy and its association with genetic variants: A systematic review

Livedoid vasculopathy (LV) is considered a disease of hypercoagulability. Association of LV with genetic variants is poorly characterised and large‐scale genetic association studies have not been performed. The aim of the study was to systematically review variants in LV patients and to analyse the available clinical data. A systematic search of the literature in PubMed and Embase databases was performed to identify articles investigating genetic variation in LV patients. Thirty studies or case reports were identified that reported 265 LV patients tested for at least one out of six genetic variations. Among them, PAI‐1 ‐675 4G/5G was the most common, accounting for 85.26% (81/95). Heterozygous 4G/5G was the major genotype. PAI‐1 A844G, MTHFR C677T, and MTHFR A1298C were the second, third, and fourth most common variants in LV patients. Prothrombin G20210A and Factor V G1691A were mainly present in LV patients from Europe, North America, and South America. This review highlights the associations between LV and genetic variants. The distribution of variants may be geographically or ethnicity dependent; however, large sample case‐control studies are needed to clarify associations.