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Science (New York, N.Y.) Sep 2023Apolipoprotein B (apoB)-lipoproteins initiate and promote atherosclerotic cardiovascular disease. Plasma tissue plasminogen activator (tPA) activity is negatively...
Apolipoprotein B (apoB)-lipoproteins initiate and promote atherosclerotic cardiovascular disease. Plasma tissue plasminogen activator (tPA) activity is negatively associated with atherogenic apoB-lipoprotein cholesterol levels in humans, but the mechanisms are unknown. We found that tPA, partially through the lysine-binding site on its Kringle 2 domain, binds to the N terminus of apoB, blocking the interaction between apoB and microsomal triglyceride transfer protein (MTP) in hepatocytes, thereby reducing very-low-density lipoprotein (VLDL) assembly and plasma apoB-lipoprotein cholesterol levels. Plasminogen activator inhibitor 1 (PAI-1) sequesters tPA away from apoB and increases VLDL assembly. Humans with PAI-1 deficiency have smaller VLDL particles and lower plasma levels of apoB-lipoprotein cholesterol. These results suggest a mechanism that fine-tunes VLDL assembly by intracellular interactions among tPA, PAI-1, and apoB in hepatocytes.
Topics: Humans; Apolipoproteins B; Atherosclerosis; Hepatocytes; Lipoproteins, VLDL; Plasminogen Activator Inhibitor 1; Tissue Plasminogen Activator; Animals; Mice; Mice, Inbred C57BL
PubMed: 37651538
DOI: 10.1126/science.adh5207 -
Stroke Oct 2023Intravenous thrombolysis via tPA (tissue-type plasminogen activator) is the only approved pharmacological treatment for acute ischemic stroke, but its benefits are... (Review)
Review
Intravenous thrombolysis via tPA (tissue-type plasminogen activator) is the only approved pharmacological treatment for acute ischemic stroke, but its benefits are limited by hemorrhagic transformation. Emerging evidence reveals that tPA swiftly mobilizes immune cells which extravasate into the brain parenchyma via the cerebral vasculature, augmenting neurovascular inflammation, and tissue injury. In this review, we summarize the pronounced alterations of immune cells induced by tPA in patients with stroke and experimental stroke models. We argue that neuroinflammation, triggered by ischemia-induced cell death and exacerbated by tPA, compromises neurovascular integrity and the microcirculation, leading to hemorrhagic transformation. Finally, we discuss current and future approaches to attenuate thrombolysis-associated hemorrhagic transformation via uncoupling immune cells from the neurovascular unit.
Topics: Humans; Ischemic Stroke; Stroke; Thrombolytic Therapy; Inflammation; Brain
PubMed: 37675612
DOI: 10.1161/STROKEAHA.123.044123 -
International Journal of Environmental... Sep 2023Cardiovascular disease (CVD) is still a leading cause of morbidity and mortality, despite all the progress achieved as regards to both prevention and treatment. Having... (Review)
Review
Cardiovascular disease (CVD) is still a leading cause of morbidity and mortality, despite all the progress achieved as regards to both prevention and treatment. Having high levels of lipoprotein(a) [Lp(a)] is a risk factor for cardiovascular disease that operates independently. It can increase the risk of developing cardiovascular disease even when LDL cholesterol (LDL-C) levels are within the recommended range, which is referred to as residual cardiovascular risk. Lp(a) is an LDL-like particle present in human plasma, in which a large plasminogen-like glycoprotein, apolipoprotein(a) [Apo(a)], is covalently bound to Apo B100 via one disulfide bridge. Apo(a) contains one plasminogen-like kringle V structure, a variable number of plasminogen-like kringle IV structures (types 1-10), and one inactive protease region. There is a large inter-individual variation of plasma concentrations of Lp(a), mainly ascribable to genetic variants in the Lp(a) gene: in the general po-pulation, Lp(a) levels can range from <1 mg/dL to >1000 mg/dL. Concentrations also vary between different ethnicities. Lp(a) has been established as one of the risk factors that play an important role in the development of atherosclerotic plaque. Indeed, high concentrations of Lp(a) have been related to a greater risk of ischemic CVD, aortic valve stenosis, and heart failure. The threshold value has been set at 50 mg/dL, but the risk may increase already at levels above 30 mg/dL. Although there is a well-established and strong link between high Lp(a) levels and coronary as well as cerebrovascular disease, the evidence regarding incident peripheral arterial disease and carotid atherosclerosis is not as conclusive. Because lifestyle changes and standard lipid-lowering treatments, such as statins, niacin, and cholesteryl ester transfer protein inhibitors, are not highly effective in reducing Lp(a) levels, there is increased interest in developing new drugs that can address this issue. PCSK9 inhibitors seem to be capable of reducing Lp(a) levels by 25-30%. Mipomersen decreases Lp(a) levels by 25-40%, but its use is burdened with important side effects. At the current time, the most effective and tolerated treatment for patients with a high Lp(a) plasma level is apheresis, while antisense oligonucleotides, small interfering RNAs, and microRNAs, which reduce Lp(a) levels by targeting RNA molecules and regulating gene expression as well as protein production levels, are the most widely explored and promising perspectives. The aim of this review is to provide an update on the current state of the art with regard to Lp(a) pathophysiological mechanisms, focusing on the most effective strategies for lowering Lp(a), including new emerging alternative therapies. The purpose of this manuscript is to improve the management of hyperlipoproteinemia(a) in order to achieve better control of the residual cardiovascular risk, which remains unacceptably high.
Topics: Humans; Cardiovascular Diseases; Lipoprotein(a); Plasminogen; Proprotein Convertase 9; Risk Factors; Serine Proteases
PubMed: 37754581
DOI: 10.3390/ijerph20186721 -
Journal of Thrombosis and Haemostasis :... Dec 2023Fibrinolysis is the system primarily responsible for removal of fibrin deposits and blood clots in the vasculature. The terminal enzyme in the pathway, plasmin, is... (Review)
Review
Fibrinolysis is the system primarily responsible for removal of fibrin deposits and blood clots in the vasculature. The terminal enzyme in the pathway, plasmin, is formed from its circulating precursor, plasminogen. Fibrin is by far the most legendary substrate, but plasmin is notoriously prolific and is known to cleave many other proteins and participate in the activation of other proteolytic systems. Fibrinolysis is often overshadowed by the coagulation system and viewed as a simplistic poorer relation. However, the primordial plasminogen activators evolved alongside the complement system, approximately 70 million years before coagulation saw the light of day. It is highly likely that the plasminogen activation system evolved with its roots in primordial immunity. Almost all immune cells harbor at least one of a dozen plasminogen receptors that allow plasmin formation on the cell surface that in turn modulates immune cell behavior. Similarly, numerous pathogens express their own plasminogen activators or contain surface proteins that provide binding sites for host plasminogen. The fibrinolytic system has been harnessed for clinical medicine for many decades with the development of thrombolytic drugs and antifibrinolytic agents. Our refined understanding and appreciation of the fibrinolytic system and its alliance with infection and immunity and beyond are paving the way for new developments and interest in novel therapeutics and applications. One must ponder as to whether the nomenclature of the system hampered our understanding, by focusing on fibrin, rather than the complex myriad of interactions and substrates of the plasminogen activation system.
Topics: Humans; Fibrinolysis; Fibrinolysin; Plasminogen Activators; Plasminogen; Fibrin; Serine Proteases
PubMed: 38000850
DOI: 10.1016/j.jtha.2023.09.012 -
Advanced Science (Weinheim,... Aug 2023The circadian clock in animals and humans plays crucial roles in multiple physiological processes. Disruption of circadian homeostasis causes detrimental effects. Here,...
The circadian clock in animals and humans plays crucial roles in multiple physiological processes. Disruption of circadian homeostasis causes detrimental effects. Here, it is demonstrated that the disruption of the circadian rhythm by genetic deletion of mouse brain and muscle ARNT-like 1 (Bmal1) gene, coding for the key clock transcription factor, augments an exacerbated fibrotic phenotype in various tumors. Accretion of cancer-associated fibroblasts (CAFs), especially the alpha smooth muscle actin positive myoCAFs, accelerates tumor growth rates and metastatic potentials. Mechanistically, deletion of Bmal1 abrogates expression of its transcriptionally targeted plasminogen activator inhibitor-1 (PAI-1). Consequently, decreased levels of PAI-1 in the tumor microenvironment instigate plasmin activation through upregulation of tissue plasminogen activator and urokinase plasminogen activator. The activated plasmin converts latent TGF-β into its activated form, which potently induces tumor fibrosis and the transition of CAFs into myoCAFs, the latter promoting cancer metastasis. Pharmacological inhibition of the TGF-β signaling largely ablates the metastatic potentials of colorectal cancer, pancreatic ductal adenocarcinoma, and hepatocellular carcinoma. Together, these data provide novel mechanistic insights into disruption of the circadian clock in tumor growth and metastasis. It is reasonably speculated that normalization of the circadian rhythm in patients provides a novel paradigm for cancer therapy.
Topics: Mice; Humans; Animals; Transforming Growth Factor beta; Tissue Plasminogen Activator; Fibrinolysin; Plasminogen Activator Inhibitor 1; Liver Neoplasms; Muscles; Brain; Tumor Microenvironment
PubMed: 37330661
DOI: 10.1002/advs.202301505 -
Journal of Dental Research Aug 2023The hemostatic and inflammatory systems work hand in hand to maintain homeostasis at mucosal barrier sites. Among the factors of the hemostatic system, fibrin is well... (Review)
Review
The hemostatic and inflammatory systems work hand in hand to maintain homeostasis at mucosal barrier sites. Among the factors of the hemostatic system, fibrin is well recognized for its role in mucosal homeostasis, wound healing, and inflammation. Here, we present a basic overview of the fibrinolytic system, discuss fibrin as an innate immune regulator, and provide recent work uncovering the role of fibrin-neutrophil activation as a regulator of mucosal/periodontal homeostasis. We reason that the role of fibrin in periodontitis becomes most evident in individuals with the Mendelian genetic defect, congenital plasminogen (PLG) deficiency, who are predisposed to severe periodontitis in childhood due to a defect in fibrinolysis. Consistent with plasminogen deficiency being a risk factor for periodontitis, recent genomics studies uncover genetic polymorphisms in , encoding plasminogen, being significantly associated with periodontal disease, and suggesting variants as candidate risk indicators for common forms of periodontitis.
Topics: Humans; Fibrinolysis; Fibrinolysin; Plasminogen; Fibrin; Periodontitis; Hemostatics
PubMed: 37506226
DOI: 10.1177/00220345231171837 -
Current Hypertension Reports Oct 2023This review article summarizes the role of coagulation in the pathogenesis of hypertension. It specifically focuses on significant factors and markers associated with... (Review)
Review
PURPOSE OF REVIEW
This review article summarizes the role of coagulation in the pathogenesis of hypertension. It specifically focuses on significant factors and markers associated with coagulation, including D-dimer, fibrinogen and fibrin, prothrombin, P-selectin, soluble urokinase plasminogen activator receptor, thrombomodulin, tissue factor, tissue plasminogen activator, von Willebrand factor, β-thromboglobulin, and Stuart-Prower factor.
RECENT FINDINGS
D-dimer levels were elevated in hypertensive individuals compared to healthy controls, and the levels increased with the severity of hypertension. These findings indicate that increased coagulation activity of fibrin plays a role in the development of thromboembolic complications in hypertensive patients. Additionally, both fibrinogen levels and D-dimer levels displayed a positive correlation with the duration of hypertension, suggesting that these biomarkers were positively associated with the length of time an individual had been hypertensive. Increased systolic and diastolic blood pressures have been linked to higher levels of prothrombin time and activated partial thromboplastin time in individuals with hypertension as well as those with normal blood pressure. Also, the presence of P-selectin, produced by activated platelets and endothelial cells during angiotensin II stimulation, played a role in the development of cardiac inflammation and fibrosis associated with hypertension. Moreover, the change in systolic blood pressure was associated with baseline soluble urokinase plasminogen activator receptor (suPAR) in hypertensive participants, and the change in suPAR levels was associated with the development of hypertension. Moreover, it was observed a decrease in thrombomodulin expression in the placenta of preeclamptic patients, suggesting its potential involvement in placental dysfunction, possibly driven by an imbalance in angiogenic factors. Tissue factors and autophagy might have significant implications in the pathogenesis of chronic thromboembolic pulmonary hypertension, particularly in the context of vascular remodelling. Likewise, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) might be a promising biomarker for the early detection of pulmonary arterial hypertension and the von Willebrand factor is a candidate prognostic biomarker. The arterial β-thromboglobulin levels were significantly lower than venous levels. This article concludes that D-dimer, fibrinogen and fibrin, prothrombin, P-selectin, soluble urokinase plasminogen activator receptor, thrombomodulin, tissue factor, tissue plasminogen activator, von Willebrand factor, and β-thromboglobulin are important factors involved in the pathogenesis of hypertension.
Topics: Humans; Female; Pregnancy; Tissue Plasminogen Activator; Hypertension; Receptors, Urokinase Plasminogen Activator; P-Selectin; Thrombomodulin; beta-Thromboglobulin; Prothrombin; Thromboplastin; von Willebrand Factor; Endothelial Cells; Placenta; Fibrinogen; Biomarkers
PubMed: 37561240
DOI: 10.1007/s11906-023-01258-0 -
Genesis (New York, N.Y. : 2000) Feb 2024Epithelial-mesenchymal transition (EMT) is an important biological process contributing to kidney fibrosis and chronic kidney disease. This process is characterized by... (Review)
Review
Epithelial-mesenchymal transition (EMT) is an important biological process contributing to kidney fibrosis and chronic kidney disease. This process is characterized by decreased epithelial phenotypes/markers and increased mesenchymal phenotypes/markers. Tubular epithelial cells (TECs) are commonly susceptible to EMT by various stimuli, for example, transforming growth factor-β (TGF-β), cellular communication network factor 2, angiotensin-II, fibroblast growth factor-2, oncostatin M, matrix metalloproteinase-2, tissue plasminogen activator (t-PA), plasmin, interleukin-1β, and reactive oxygen species. Similarly, glomerular podocytes can undergo EMT via these stimuli and by high glucose condition in diabetic kidney disease. EMT of TECs and podocytes leads to tubulointerstitial fibrosis and glomerulosclerosis, respectively. Signaling pathways involved in EMT-mediated kidney fibrosis are diverse and complex. TGF-β1/Smad and Wnt/β-catenin pathways are the major venues triggering EMT in TECs and podocytes. These two pathways thus serve as the major therapeutic targets against EMT-mediated kidney fibrosis. To date, a number of EMT inhibitors have been identified and characterized. As expected, the majority of these EMT inhibitors affect TGF-β1/Smad and Wnt/β-catenin pathways. In addition to kidney fibrosis, these EMT-targeted antifibrotic inhibitors are expected to be effective for treatment against fibrosis in other organs/tissues.
Topics: Humans; Transforming Growth Factor beta1; beta Catenin; Matrix Metalloproteinase 2; Tissue Plasminogen Activator; Epithelial Cells; Wnt Signaling Pathway; Epithelial-Mesenchymal Transition; Kidney; Fibrosis
PubMed: 37345818
DOI: 10.1002/dvg.23529 -
Current Opinion in Pediatrics Dec 2023The purpose of this paper is to review recent updates in the acute management of childhood arterial ischemic stroke, including reperfusion therapies and neuroprotective... (Review)
Review
PURPOSE OF REVIEW
The purpose of this paper is to review recent updates in the acute management of childhood arterial ischemic stroke, including reperfusion therapies and neuroprotective measures.
RECENT FINDINGS
With the emergence of pediatric stroke centers in recent years, processes facilitating rapid diagnosis and treatment have resulted in improved implementation of early targeted neuroprotective measures as well as the increased use of reperfusion therapies in childhood arterial ischemic stroke. Retrospective data has demonstrated that alteplase is safe in carefully selected children with arterial ischemic stroke in the first 4.5 h from symptom onset, though data regarding its efficacy in children are still lacking. There is also increasing data that suggests that thrombectomy in children with large vessel occlusion improves functional outcomes. Recent adult studies, including the use of Tenecteplase as an alteplase alternative and expansion of late thrombectomy to include patients with large ischemic cores, also are reviewed along with limitations to application of the adult data to pediatric care.
SUMMARY
There have been significant advances in the hyperacute care of children with ischemic stroke and early diagnosis and targeted management are of the upmost importance in improving long-term outcomes.
Topics: Adult; Child; Humans; Tissue Plasminogen Activator; Fibrinolytic Agents; Retrospective Studies; Stroke; Ischemic Stroke; Treatment Outcome; Brain Ischemia
PubMed: 37800414
DOI: 10.1097/MOP.0000000000001295