Reactive Oxygen Species in Venous Thrombosis

Site-specific thrombus formation: advancements in photothrombosis-on-a-chip technology

Thrombosis, characterized by blood clot formation within vessels, poses a significant medical challenge. Despite extensive research, the development of effective thrombosis therapies is hindered by substantial costs, lengthy development times, and high failure rates in medication commercialization. Conventional pre-clinical models often oversimplify cardiovascular disease, leading to a disparity between experimental results and human physiological responses. In response, we have engineered a photothrombosis-on-a-chip system. This microfluidic model integrates human endothelium, human whole blood, and blood flow dynamics and employs the photothrombotic method. It enables precise, site-specific thrombus induction through controlled laser irradiation, effectively mimicking both normal and thrombotic physiological conditions on a single chip. Additionally, the system allows for the fine-tuning of thrombus occlusion levels via laser parameter adjustments, offering a flexible thrombus model with varying degrees of obstruction. Additionally, the formation and progression of thrombosis noted on the chip closely resemble the thrombotic conditions observed in mice in previous studies. In the experiments, we perfused recalcified whole blood with Rose Bengal into an endothelialized microchannel and initiated photothrombosis using green laser irradiation. Various imaging methods verified the model's ability to precisely control thrombus formation and occlusion levels. The effectiveness of clinical drugs, including heparin and rt-PA, was assessed, confirming the chip's potential in drug screening applications. In summary, the photothrombosis-on-a-chip system significantly advances human thrombosis modeling. Its precise control over thrombus formation, flexibility in the thrombus severity levels, and capability to simulate dual physiological states on a single platform make it an invaluable tool for targeted drug testing, furthering the development of organ-on-a-chip drug screening techniques.

Oxidative Status, Iron Plasma Levels in Venous Thrombosis Patients

Exaggerated clot induces venous thrombosis (VTE); oxidative stress (OxS) can to be postulated as additional risk factor. This study evaluates firstly OxS by measuring surrogate biomarkers (malondialdehyde-MDA, 4-hydroxinonenal-4-HNE, superoxide desmutase enzyme (SOD)), secondly the iron (Fe) plasma level and thirdly the hepcidin protein (Hep) level in patients with VTE. A case control study was performed enrolling twenty hospitalized patients and an equal number of healthy individuals. In VTE patients, the following results were found. The MDA was 8.38 ± 0.5 µM/L, the 4-HNE measured 2.75 ± 0.03 µM/L and the SOD was 0.025 ± 0.01 U/mL. The I was 73.10 ± 10 µg/dL and the He was 4.77 ± 0.52 ng/mL. In the control group, the MDA measured 5.5 ± 0.6 µM/L, the 4-HNE 2.24 ± 0.021 µM/L and the SOD 0.08 ± 0.12 U/mL. The Hep was 2.1 ± 0.55 ng/mL and the Fe was 88.2 ± 9.19 µg/dL. Differences were statistically significant. Results suggest that in VTE there is activated OxS, Fe deregulation and over-production of Hep. Fe deregulation induces OxS, leading both to inflammation in the clot activator and stimulation of the pro-thrombotic status. The study highlights OxS and Fe and their regulation as intriguing indicators for risk of VTE.

Advances in Nano-Functional Materials in Targeted Thrombolytic Drug Delivery

Thrombotic disease has been listed as the third most fatal vascular disease in the world. After decades of development, clinical thrombolytic drugs still cannot avoid the occurrence of adverse reactions such as bleeding. A number of studies have shown that the application of various nano-functional materials in thrombus-targeted drug delivery, combined with external stimuli, such as magnetic, near-infrared light, ultrasound, etc., enrich the drugs in the thrombus site and use the properties of nano-functional materials for collaborative thrombolysis, which can effectively reduce adverse reactions such as bleeding and improve thrombolysis efficiency. In this paper, the research progress of organic nanomaterials, inorganic nanomaterials, and biomimetic nanomaterials for drug delivery is briefly reviewed.

Endothelial PTP1B Deletion Promotes VWF Exocytosis and Venous Thromboinflammation

BACKGROUND

Endothelial activation promotes the release of procoagulant extracellular vesicles and inflammatory mediators from specialized storage granules. Endothelial membrane exocytosis is controlled by phosphorylation. We hypothesized that the absence of PTP1B (protein tyrosine phosphatase 1B) in endothelial cells promotes venous thromboinflammation by triggering endothelial membrane fusion and exocytosis.

METHODS

Mice with inducible endothelial deletion of PTP1B (End.PTP1B-KO) underwent inferior vena cava ligation to induce stenosis and venous thrombosis. Primary endothelial cells from transgenic mice and human umbilical vein endothelial cells were used for mechanistic studies.

RESULTS

Vascular ultrasound and histology showed significantly larger venous thrombi containing higher numbers of Ly6G (lymphocyte antigen 6 family member G)-positive neutrophils in mice with endothelial PTP1B deletion, and intravital microscopy confirmed the more pronounced neutrophil recruitment following inferior vena cava ligation. RT2 PCR profiler array and immunocytochemistry analysis revealed increased endothelial activation and adhesion molecule expression in primary End.PTP1B-KO endothelial cells, including CD62P (P-selectin) and VWF (von Willebrand factor). Pretreatment with the NF-κB (nuclear factor kappa B) kinase inhibitor BAY11-7082, antibodies neutralizing CD162 (P-selectin glycoprotein ligand-1) or VWF, or arginylglycylaspartic acid integrin-blocking peptides abolished the neutrophil adhesion to End.PTP1B-KO endothelial cells in vitro. Circulating levels of annexin V+ procoagulant endothelial CD62E+ (E-selectin) and neutrophil (Ly6G+) extracellular vesicles were also elevated in End.PTP1B-KO mice after inferior vena cava ligation. Higher plasma MPO (myeloperoxidase) and Cit-H3 (citrullinated histone-3) levels and neutrophil elastase activity indicated neutrophil activation and extracellular trap formation. Infusion of End.PTP1B-KO extracellular vesicles into C57BL/6J wild-type mice most prominently enhanced the recruitment of endogenous neutrophils, and this response was blunted in VWF-deficient mice or by VWF-blocking antibodies. Reduced PTP1B binding and tyrosine dephosphorylation of SNAP23 (synaptosome-associated protein 23) resulting in increased VWF exocytosis and neutrophil adhesion were identified as mechanisms, all of which could be restored by NF-κB kinase inhibition using BAY11-7082.

CONCLUSIONS

Our findings show that endothelial PTP1B deletion promotes venous thromboinflammation by enhancing SNAP23 phosphorylation, endothelial VWF exocytosis, and neutrophil recruitment.

Endothelial transferrin receptor 1 contributes to thrombogenesis through cascade ferroptosis

Oxidative stress and iron accumulation-induced ferroptosis occurs in injured vascular cells and can promote thrombogenesis. Transferrin receptor 1 (encoded by the TFRC gene) is an initial element involved in iron transport and ferroptosis and is highly expressed in injured vascular tissues, but its role in thrombosis has not been determined. To explore the potential mechanism and therapeutic effect of TFRC on thrombogenesis, a DVT model of femoral veins (FVs) was established in rats, and weighted correlation network analysis (WGCNA) was used to identify TFRC as a hub protein that is associated with thrombus formation. TFRC was knocked down by adeno-associated virus (AAV) or lentivirus transduction in FVs or human umbilical vein endothelial cells (HUVECs), respectively. Thrombus characteristics and ferroptosis biomarkers were evaluated. Colocalization analysis, molecular docking and coimmunoprecipitation (co-IP) were used to evaluate protein interactions. Tissue-specific TFRC knockdown alleviated iron overload and redox stress, thereby preventing ferroptosis in injured FVs. Loss of TFRC in injured veins could alleviate thrombogenesis, reduce thrombus size and attenuate hypercoagulability. The protein level of thrombospondin-1 (THBS1) was increased in DVT tissues, and silencing TFRC decreased the protein level of THBS1. In vitro experiments further showed that TFRC and THBS1 were sensitive to erastin-induced ferroptosis and that TFRC knockdown reversed this effect. TFRC can interact with THBS1 in the domain spanning from TSR1-2 to TSR1-3 of THBS1. Amino acid sites, including GLN320 of TFRC and ASP502 of THBS1, could be potential pharmacological targets. Erastin induced ferroptosis affected extracellular THBS1 levels and weakened the interaction between TFRC and THBS1 both in vivo and in vitro, and promoted the interaction between THBS1 and CD47. This study revealed a linked relationship between venous ferroptosis and coagulation cascades. Controlling TFRC and ferroptosis in endothelial cells can be an efficient approach for preventing and treating thrombogenesis.

Reduced Monocyte and Neutrophil Infiltration and Activation by P-Selectin/CD62P Inhibition Enhances Thrombus Resolution in Mice

BACKGROUND

Venous thromboembolism is a major health problem. After thrombus formation, its resolution is essential to re-establish blood flow, which is crucially mediated by infiltrating neutrophils and monocytes in concert with activated platelets and endothelial cells. Thus, we aimed to modulate leukocyte function during thrombus resolution post-thrombus formation by blocking P-selectin/CD62P-mediated cell interactions.

METHODS

Thrombosis was induced by inferior vena cava stenosis through ligation in mice. After 1 day, a P-selectin-blocking antibody or isotype control was administered and thrombus composition and resolution were analyzed.

RESULTS

Localizing neutrophils and macrophages in thrombotic lesions of wild-type mice revealed that these cells enter the thrombus and vessel wall from the caudal end. Neutrophils were predominantly present 1 day and monocytes/macrophages 3 days after vessel ligation. Blocking P-selectin reduced circulating platelet-neutrophil and platelet-Ly6Chigh monocyte aggregates near the thrombus, and diminished neutrophils and Ly6Chigh macrophages in the cranial thrombus part compared with isotype-treated controls. Depletion of neutrophils 1 day after thrombus initiation did not phenocopy P-selectin inhibition but led to larger thrombi compared with untreated controls. In vitro, P-selectin enhanced human leukocyte function as P-selectin-coated beads increased reactive oxygen species production by neutrophils and tissue factor expression of classical monocytes. Accordingly, P-selectin inhibition reduced oxidative burst in the thrombus and tissue factor expression in the adjacent vessel wall. Moreover, blocking P-selectin reduced thrombus density determined by scanning electron microscopy and increased urokinase-type plasminogen activator levels in the thrombus, which accelerated caudal fibrin degradation from day 3 to day 14. This accelerated thrombus resolution as thrombus volume declined more rapidly after blocking P-selectin.

CONCLUSIONS

Inhibition of P-selectin-dependent activation of monocytes and neutrophils accelerates venous thrombosis resolution due to reduced infiltration and activation of innate immune cells at the site of thrombus formation, which prevents early thrombus stabilization and facilitates fibrinolysis.

Fisetin Alleviates Inflammation and Oxidative Stress in Deep Vein Thrombosis via MAPK and NRF2 Signaling Pathway

Oxidative stress and inflammation play pivotal roles in the progression of deep vein thrombosis (DVT). Fisetin has demonstrated promising pharmacological features; however, its underlying mechanisms in DVT remain elusive. In our study, we investigated the effects and underlying mechanisms of Fisetin on a DVT mouse model. The protective effects of Fisetin on DVT were evaluated by comparing the size of thrombosis and detecting the mRNA expression levels of pro-inflammatory cytokines. After that, the biological processes were studied via transcriptomics after Fisetin administration. The antioxidant effect was evaluated and explained via NRF2 signaling pathway. Finally, the anti-inflammatory effect was explained according to KEGG analysis and the final mechanism was verified via Western blot. Our results found that the mRNA expression levels of pro-inflammatory cytokines were inhibited by Fisetin. Moreover, transcriptomic studies suggested that MAPK signaling pathway may be associated with the anti-inflammatory activity of Fisetin. Then, we confirmed that Fisetin administration significantly inhibited the activation of typical pro-inflammatory signaling pathways via Western blot. Finally, the results of Western blot showed that Fisetin significantly activated NRF2 signaling pathway and induced the expression of downstream antioxidant enzymes. Our findings suggested that Fisetin exhibits potential therapeutic effects on DVT through its ability to attenuate inflammation and oxidative stress. The underlying mechanism may involve the suppression of MAPK-mediated inflammatory signaling pathway and activation of NRF2-mediated antioxidant signaling pathway.

Phloretin targets SIRT1 to alleviate oxidative stress, apoptosis, and inflammation in deep venous thrombosis

Deep vein thrombosis (DVT) is a type of venous thromboembolism posing a serious threat to health on a global scale. Phloretin is a potential natural product that has a variety of pharmacological activities. Besides, some Chinese medicines reported that deacetylase sirtuin (SIRT)1 treats DVT by anti-inflammatory and anti-platelet production. However, the specific binding targets and binding modes have not been elaborated. The present study was to investigate whether phloretin attenuates DVT in model rats and oxidized low‑density lipoprotein (ox‑LDL) induced human umbilical vein endothelial cells (HUVECs), and to explore its potential target. The results revealed that the treatment of phloretin, especially pretreatment of it elevated tissue plasminogen activator (t-PA), superoxide dismutase (SOD), prothrombin time (PT), thrombin time (TT), activated partial thromboplastin time (APTT), and cell apoptosis proteins whereas it suppressed plasminogen activator inhibitor (PAI), malondialdehyde (MDA), reactive oxygen species (ROS), fibrinogen (FIB) in DVT rats and cells. Concurrently, phloretin inhibited collagen type I alpha 1 (COL1A1), transforming growth factor-β1 (TGF-β1), and inflammatory factors while it enhanced nuclear factor erythroid 2-related factor 2 (Nrf-2), heme oxygenase 1 (HO-1). In addition, 20 μM phloretin exerted powerful effective protection in HUVECs with DVT model. Later, the surface plasmon resonance (SPR) confirmed that phloretin has a high affinity with SIRT1. Furthermore, siRNA-SIRT1 transfection abolished the protective effect of phloretin against ox‑LDL‑induced DVT in HUVECs, indicating that phloretin targets SIRT1 to alleviate oxidative stress, cell apoptosis, and inflammation in DVT rats and HUVECs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-023-00207-y.

Bisphenol S remodels red blood cell membrane lipids by altering plasma lipid levels, causing the risk of venous thrombosis in SD rats and zebrafish embryos

Bisphenol S (BPS) is a raw material that is used extensively in various manufacturing processes but possesses a high detection rate in human red blood cells (RBCs). Accordingly, BPS is a potential toxicant in disturbing the function of RBCs and causing RBC-related diseases. To date, the effects and mechanisms of BPS-induced RBC-related diseases have not been elucidated. Here, using different models, including rats, zebrafish embryos and RBCs, the underlying mechanism of RBC-related diseases induced by BPS was explored. The accumulation of BPS in tissue was colon > kidney > liver > plasma > testicle > heart > brain in SD rats orally administered BPS (10 and 50 mg/kg bw/day) for 32 days, which was similar in both 10 mg/kg bw/day and 50 mg/kg bw/day group. Rats given BPS orally developed hyperlipidemia and increased RBC membrane cholesterol, as well as changes in RBC morphology and function. Moreover, BPS at the concentrations measured in rats plasma caused oxidative stress and phosphatidylserine exposure in vitro RBCs. These combined factors led to RBC aggregation in blood and an increasing in the number of RBCs in the blood vessels of the liver in rats. The dynamic visual observation of RBCs in vein vessels of zebrafish embryos exposed to BPS at 0, 1, 10 and 100 μg/L further found that the flow of RBCs in the tail vein is slow or even immobile, posing the risk of venous thrombosis. The present study provides new insight into the links between environmental pollutants and venous thrombosis.

Effect of intermittent pneumatic compression on preventing deep vein thrombosis using microfluidic vein chip

Background: Deep Vein Thrombosis (DVT) is a common disease, frequently afflicting the lower limb veins of bedridden patients. Intermittent Pneumatic Compression (IPC) is often employed as an effective solution for this problem. In our study, a random selection of 264 patients underwent IPC treatment for either one or 8 hours daily. The rate of severe venous thrombosis was substantially reduced in the IPC-treated group compared to the control group. However, real-time monitoring of blood flow during IPC operation periods remains a challenge, leading to rare awareness of IPC working mechanism on thrombosis prevention. Methods: Here, microfluidic chip methodology is used to create an in vitro vein-mimicking platform integrating venous valves in a deformable channel. Whole blood of patients after knee surgery was perfused into the venous channel at a controlled flow rate obtained from patients with IPC treatment clinically. Results: According to the numerical simulations results, both of an increase in compressive pressure and a decrease in time interval of IPC device can accelarete blood flow rate and the shear stress within the vein. The vein chip experiments also reveal that the fibrin accumulation can be greatly lowered in IPC treated group, indicating less thrombosis formation in future. A time interval of 24 seconds and a maximum contraction pressure of 40 mmHg were proved to be the most effective parameters for the IPC device adopted in our clinical trail. Conclusion: This vein chip presents a novel method for observing the functional mechanisms of IPC device for DVT prevention. It provides crucial data for further standardization and optimization of IPC devices in clinical usage.

Severe fever with thrombocytopenia syndrome virus induces platelet activation and apoptosis via a reactive oxygen species-dependent pathway

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease caused by the SFTS virus (SFTSV) and with a high fatality rate. Thrombocytopenia is a major clinical manifestation observed in SFTS patients, but the underlying mechanism remains largely unclear. Here, we explored the effects of SFTSV infection on platelet function in vivo in severely infected SFTSV IFNar-/- mice and on mouse and human platelet function in vitro. Results showed that SFTSV-induced platelet clearance acceleration may be the main reason for thrombocytopenia. SFTSV-potentiated platelet activation and apoptosis were also observed in infected mice. Further investigation showed that SFTSV infection induced platelet reactive oxygen species (ROS) production and mitochondrial dysfunction. In vitro experiments revealed that administration of SFTSV or SFTSV glycoprotein (Gn) increased activation, apoptosis, ROS production, and mitochondrial dysfunction in separated mouse platelets, which could be effectively ameliorated by the application of antioxidants (NAC (N-acetyl-l-cysteine), SKQ1 (10-(6'-plastoquinonyl) decyltriphenylphosphonium) and resveratrol). In vivo experiments showed that the antioxidants partially rescued SFTSV infection-induced thrombocytopenia by improving excessive ROS production and mitochondrial dysfunction and down-regulating platelet apoptosis and activation. Furthermore, while SFTSV and Gn directly potentiated human platelet activation, it was completely abolished by antioxidants. This study revealed that SFTSV and Gn can directly trigger platelet activation and apoptosis in an ROS-MAPK-dependent manner, which may contribute to thrombocytopenia and hemorrhage during infection, but can be abolished by antioxidants.

TXNIP activates NLRP3/IL-1β and participate in inflammatory response and oxidative stress to promote deep venous thrombosis

Increasing evidence indicates that deep venous thrombosis (DVT) is a common peripheral vascular disease. This study aims to investigate the mechanisms of thioredoxin-interacting protein (TXNIP) and nod-like receptor protein 3 (NLRP3) inflammasome in deep venous thrombosis (DVT). A total of 66 Sprague-Dawley (SD) rats were employed to conduct DVT model. DVT rat was treated with silenced TXNIP (si-TXNIP) lentivirus and MCC950 (a NLRP3 inhibitor). The thrombosis weight and weight/length ratio, tissue factor, inflammatory factors, superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) were measured. Hematoxylin-eosin (H&E) staining was used to investigate the pathological change. Western blotting was used to determine the protein expression level. The expression level of thioredoxin (TRx) was suppressed, whereas TXNIP and NLRP3 were elevated in DVT rat. Si-TXNIP or MCC950 could reduce the thrombosis weight and weight/length ratio, ameliorate the pathological change, and decrease inflammatory reaction. Mechanistically, si-TXNIP or MCC950 inhibited the expression levels of TXNIP, NLRP3, and interleukin (IL)-1β while elevating the TRx level, thereby suppressing the DVT. Our study indicated that si-TXNIP or MCC950 injection rescued the injury of vein induced by DVT. The possible mechanisms connected with the inhibition of TXNIP and NLRP3. TXNIP is a possible therapeutic target for DVT.

Prussian blue nanozymes: progress, challenges, and opportunities

Prussian Blue Nanozymes (PBNZs) have emerged as highly efficient agents for reactive oxygen species (ROS) elimination, owing to their multiple enzyme-like properties encompassing catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities. As a functional nanomaterial mimicking enzyme, PBNZs not only surmount the limitations of natural enzymes, such as instability and high manufacturing costs, but also exhibit superior stability, tunable activity, low storage expenses, and remarkable reusability. Consequently, PBNZs have gained significant attention in diverse biomedical applications, including disease diagnosis and therapy. Over the past decade, propelled by advancements in catalysis science, biotechnology, computational science, and nanotechnology, PBNZs have witnessed remarkable progress in the exploration of their enzymatic activities, elucidation of catalytic mechanisms, and wide-ranging applications. This comprehensive review aims to provide a systematic overview of the discovery and catalytic mechanisms of PBNZ, along with the strategies employed to modulate their multiple enzyme-like activities. Furthermore, we extensively survey the recent advancements in utilizing PBNZs for scavenging ROS in various biomedical applications. Lastly, we analyze the existing challenges of translating PBNZs into therapeutic agents for clinical use and outline future research directions in this field. By presenting a comprehensive synopsis of the current state of knowledge, this review seeks to contribute to a deeper understanding of the immense potential of PBNZs as an innovative therapeutic agent in biomedicine.

Long Non-Coding RNAs in Venous Thromboembolism: Where Do We Stand?

Venous thromboembolism (VTE), a common condition in Western countries, is a cardiovascular disorder that arises due to haemostatic irregularities, which lead to thrombus generation inside veins. Even with successful treatment, the resulting disease spectrum of complications considerably affects the patient's quality of life, potentially leading to death. Cumulative data indicate that long non-coding RNAs (lncRNAs) may have a role in VTE pathogenesis. However, the clinical usefulness of these RNAs as biomarkers and potential therapeutic targets for VTE management is yet unclear. Thus, this article reviewed the emerging evidence on lncRNAs associated with VTE and with the activity of the coagulation system, which has a central role in disease pathogenesis. Until now, ten lncRNAs have been implicated in VTE pathogenesis, among which MALAT1 is the one with more evidence. Meanwhile, five lncRNAs have been reported to affect the expression of TFPI2, an important anticoagulant protein, but none with a described role in VTE development. More investigation in this field is needed as lncRNAs may help dissect VTE pathways, aiding in disease prediction, prevention and treatment.

X-rays Stimulate Granular Secretions and Activate Protein Kinase C Signaling in Human Platelets

X-rays can induce morphological as well as functional changes in cells. Platelets are anuclear cellular fragments originating from megakaryocytes and are the major regulators in hemostasis and thrombosis. Platelet products are irradiated to avoid medical complications associated with platelet transfusion. So far, gamma, UV, and laser radiation have been used for this purpose. However, scientists are divided about the effects of radiation on platelet quality. The present study was designed to explore the possible effects of X-rays in washed human platelets and understand the molecular mechanism behind them. In the present study, we exposed washed human platelets to 10 or 30 Gy X-rays at 0.25 Gy/min. Flow cytometry, aggregometry, and western blot were performed to investigate the effect of X-rays on platelet degranulation, integrin activation, platelet aggregation, and apoptosis. It was found that X-rays immediately induced granular secretions with no effect on GP IIb/IIIa activation. Not surprisingly, due to granule secretions in irradiated platelets, platelet aggregation was significantly reduced. In contrast to granular secretions and platelet aggregation, X-rays induced mitochondrial transmembrane potential depolarization in a time-dependent manner to induce apoptosis and activated protein kinase C (PKC) signaling. This study revealed and explained the molecular mechanism activated by X-rays in washed human platelets. Here we also introduced Gö 6983, a PKC inhibitor, as an agent that counteracts X-ray-induced changes and maintains the integrity of platelets.

Activation of aldehyde dehydrogenase-2 improves ischemic random skin flap survival in rats

Objective

Random skin flaps have many applications in plastic and reconstructive surgeries. However, distal flap necrosis restricts wider clinical utility. Mitophagy, a vital form of autophagy for damaged mitochondria, is excessively activated in flap ischemia/reperfusion (I/R) injury, thus inducing cell death. Aldehyde dehydrogenase-2 (ALDH2), an allosteric tetrameric enzyme, plays an important role in regulating mitophagy. We explored whether ALDH2 activated by N-(1,3-benzodioxol-5-ylmethyl)-2,6-dichlorobenzamide (Alda-1) could reduce the risk of ischemic random skin flap necrosis, and the possible mechanism of action.

Methods

Modified McFarlane flap models were established in 36 male Sprague-Dawley rats assigned randomly to three groups: a low-dose Alda-1 group (10 mg/kg/day), a high-dose Alda-1 group (20 mg/kg/day) and a control group. The percentage surviving skin flap area, neutrophil density and microvessel density (MVD) were evaluated on day 7. Oxidative stress was quantitated by measuring the superoxide dismutase (SOD) and malondialdehyde (MDA) levels. Blood perfusion and skin flap angiogenesis were assessed via laser Doppler flow imaging and lead oxide-gelatin angiography, respectively. The expression levels of inflammatory cytokines (IL-1β, IL-6, and TNF-α), vascular endothelial growth factor (VEGF), ALDH2, PTEN-induced kinase 1 (PINK1), and E3 ubiquitin ligase (Parkin) were immunohistochemically detected. Indicators of mitophagy such as Beclin-1, p62, and microtubule-associated protein light chain 3 (LC3) were evaluated by immunofluorescence.

Results

Alda-1 significantly enhanced the survival area of random skin flaps. The SOD activity increased and the MDA level decreased, suggesting that Alda-1 reduced oxidative stress. ALDH2 was upregulated, and mitophagy-related proteins (PINK1, Parkin, Beclin-1, p62, and LC3) were downregulated, indicating that ALDH2 inhibited mitophagy through the PINK1/Parkin signaling pathway. Treatment with Alda-1 reduced neutrophil infiltration and expressions of inflammatory cytokines. Alda-1 significantly upregulated VEGF expression, increased the MVD, promoted angiogenesis, and enhanced blood perfusion.

Conclusion

ALDH2 activation can effectively enhance random skin flap viability via inhibiting PINK1/Parkin-dependent mitophagy. Moreover, enhancement of ALDH2 activity also exerts anti-inflammatory and angiogenic properties.

Antioxidant role of methionine-containing intra- and extracellular proteins

Significant evidence suggests that reversible oxidation of methionine residues provides a mechanism capable of scavenging reactive species, thus creating a cycle with catalytic efficiency to counteract or mitigate deleterious effects of ROS on other functionally important amino acid residues. Because of the absence of MSRs in the blood plasma, oxidation of methionines in extracellular proteins is effectively irreversible and, therefore, the ability of methionines to serve as interceptors of oxidant molecules without impairment of the structure and function of plasma proteins is still debatable. This review presents data on the oxidative modification of both intracellular and extracellular proteins that differ drastically in their spatial structures and functions indicating that the proteins contain antioxidant methionines/the oxidation of which does not affect (or has a minor effect) on their functional properties. The functional consequences of methionine oxidation in proteins have been mainly identified from studies in vitro and, to a very limited extent, in vivo. Hence, much of the functioning of plasma proteins constantly subjected to oxidative stress remains unclear and requires further research to understand the evolutionary role of methionine oxidation in proteins for the maintenance of homeostasis and risk factors affecting the development of ROS-related pathologies. Data presented in this review contribute to increased evidence of antioxidant role of surface-exposed methionines and can be useful for understanding a possible mechanism that supports or impairs structure-function relationships of proteins subjected to oxidative stress.

Antioxidant Properties of Oral Antithrombotic Therapies in Atherosclerotic Disease and Atrial Fibrillation

The thrombosis-related diseases are one of the leading causes of illness and death in the general population, and despite significant improvements in long-term survival due to remarkable advances in pharmacologic therapy, they continue to pose a tremendous burden on healthcare systems. The oxidative stress plays a role of pivotal importance in thrombosis pathophysiology. The anticoagulant and antiplatelet drugs commonly used in the management of thrombosis-related diseases show several pleiotropic effects, beyond the antithrombotic effects. The present review aims to describe the current evidence about the antioxidant effects of the oral antithrombotic therapies in patients with atherosclerotic disease and atrial fibrillation.

Association of gamma-glutamyl transferase variability with risk of venous thrombosis

Gamma-glutamyl transferase (GGT) is a biomarker of inflammation, and is known to be associated with stroke and atrial fibrillation. Venous thromboembolism (VT), a not uncommon thrombotic disorder, shares similar mechanisms with other thrombotic disorders including these stroke and atrial fibrillation. Given these associations, we intended to investigate the potential association between variability in GGT and VT. The study included data from the National Health Insurance Service-Health Screening Cohort, comprising 1,085,105 participants with health examinations 3 or more times from 2003 to 2008. Variability indexes were the coefficient of variation, standard deviation, and variability independent of the mean. The occurrence of venous thromboembolism (VT) was defined with more than one claim of the following ICD-10 codes: deep VT (I80.2-80.3), pulmonary thromboembolism (I26), intraabdominal venous thrombosis (I81, I82.2, I82.3), or other VT (I82.8, I82.9). To determine the relationship of quartiles of GGT with incident VT risk, Kaplan-Meier survival curve and logrank test were used. Cox's proportional hazard regression was used to investigate the risk of VT occurrence by GGT quartile (Q1-Q4). A total of 1,085,105 subjects were incorporated in the analysis, and the average follow-up was 12.4 years (interquartile range 12.2-12.6). VT occurred in 11,769 (1.08%) patients. The GGT level was measured 5,707,768 times in this stud. Multivariable analysis showed that GGT variability were positively associated with the occurrence of VT. Compared to the Q1, the Q4 showed an adjusted HR of 1.15 (95% CI 1.09-1.21, p < 0.001) when using coefficient of variation, 1.24 (95% CI 1.17-1.31, p < 0.001) when using standard deviation, and 1.10 (95% CI 1.05-1.16, p < 0.001) when using variability independent of the mean. Increased variability of GGT may be related to an increased risk of VT. Maintaining a stable GGT level would be beneficial in reducing the risk of VT.

Thrombosis in the pathogenesis of abdominal aortic aneurysm

Background

Abdominal aortic aneurysms (AAAs) are a relatively common vascular pathology of the elderly with high morbidity potential. Irreversible degeneration of the aortic wall leads to lethal rupture if left untreated. Nearly all AAAs contain intraluminal thrombus (ILT) to a varying degree, yet the mechanisms explaining how thrombosis is disturbed in AAA are relatively unknown. This review examined the thrombotic complications associated with AAA, the impact of thrombosis on AAA surgical outcomes and AAA pathogenesis, and the use of antithrombotic therapy in the management of this disease.

Methods

A literature search of the PubMed database was conducted using relevant keywords related to thrombosis and AAAs.

Results

Thrombotic complications are relatively infrequent in AAA yet carry significant morbidity risks. The ILT can impact endovascular aneurysm repair by limiting anatomic suitability and influence the risk of endoleaks. Many of the pathologic mechanisms involved in AAA development, including hemodynamics, inflammation, oxidative stress, and aortic wall remodeling, contain pathways that interact with thrombosis. Conversely, the ILT can also be a source of biochemical stress and exacerbate these aneurysmal processes. In animal AAA models, antithrombotic therapies have shown favorable results in preventing and stabilizing AAA. Antiplatelet agents may be beneficial for reducing risks of major adverse cardiovascular events in AAA patients; however, neither antiplatelet nor anticoagulation is currently used solely for the management of AAA.

Conclusions

Thrombosis and ILT may have detrimental effects on AAA growth, rupture risk, and patient outcomes, yet there is limited understanding of the pathologic thrombotic mechanisms in aneurysmal disease at the molecular level. Preventing ILT using platelet and coagulation inhibitors may be a reasonable theoretical target for aneurysm progression and stability; however, the practical benefits of current antithrombotic therapies in AAA are unclear. Further research is needed to demonstrate the extent to which thrombosis impacts AAA pathogenesis and to develop novel pharmacologic strategies for the medical management of this disease.

Circulating adipokine concentrations and the risk of venous thromboembolism: A Mendelian randomization and mediation analysis

Background: Previous observational studies have suggested that circulating adipokine concentrations are related to a greater risk of venous thromboembolism (VTE). However, it remained unclear whether these observations reflect causality.

Objective: This study aimed to investigate the causal relationship between circulating adipokine concentrations (including adiponectin, leptin, PAI-1, MCP-1, leptin receptor, and RETN) and the risk of VTE and its subtypes (DVT and PE) and to determine whether circulating adipokine concentrations are a mediator of venous thromboembolic events in obese patients.

Methods: We used Mendelian randomization (MR) analyses to determine the effects of the body mass index (BMI), adiponectin, leptin, PAI-1, MCP-1, leptin receptor, and RETN levels on VTE, DVT, and PE in a cohort of 11,288 VTE cases, 5,632 DVT cases, 5,130 PE cases, and 254,771 controls. We then assessed the proportion of the effect of obesity on VTE, DVT, and PE explained by circulating leptin levels.

Result: Genetically predicted higher BMI was related to increased VTE (OR = 1.45, p &lt; 0.001), DVT (OR = 1.63, p &lt; 0.001), and PE (OR = 1.37, p &lt; 0.001) risk, and higher circulating leptin levels increase odds of VTE (OR = 1.96, q &lt; 0.001), DVT (OR = 2.52, q &lt; 0.001), and PE (OR = 2.26, q = 0.005). In addition, we found that the causal effect between elevated serum adiponectin and the decreased risk of VTE (OR = 0.85, p = 0.013, q = 0.053) and PE (OR = 0.81, p = 0.032, q = 0.083) and between MCP-1 and the reduced risk of VTE (OR = 0.88, p = 0.048, q = 0.143) is no longer significant after FDR adjustment. In MR mediation analysis, the mediation effect of circulating leptin levels in the causal pathway from BMI to PE was estimated to be 1.28 (0.95–1.71, p = 0.10), accounting for 39.14% of the total effect.

Conclusion: The circulating leptin level is a risk factor for VTE, DVT, and PE, but it might be a potential mediator of BMI on the risk of PE, and thus, interventions on the circulating leptin level in obesity might reduce the risk of PE. Adiponectin is a potential protective factor for both VTE and PE.

Pediatric Philadelphia-Negative Myeloproliferative Neoplasms in the Era of WHO Classification: A Systematic Review

BACKGROUND

Philadelphia-negative myeloproliferative neoplasms (MPN) are most prevalent in the older population (median age at the diagnosis is above 60 years) and rarely diagnosed in pediatrics. Thus, our knowledge about the clinical presentation, mutational status, and complications of MPNs in pediatrics is limited.

METHODS

The literature in English (PubMed, SCOPUS, and Google Scholar) was searched for studies, reviews, case series, and case reports of patients with Philadelphia-negative MPNs (including essential thrombocythemia, polycythemia vera, primary myelofibrosis, and profibrotic myelofibrosis) in the pediatrics age group (less than 18 years). Only studies that fulfilled WHO 2008 or 2016 criteria for MPNs were included. We aimed to describe the clinical characteristics, vascular and long-term complications, types of driver mutations, and treatment approaches in pediatric patients with MPNs.

RESULTS

We reviewed 33 articles of available published literature from 2008 to 2022 and collected data from a total of 196 patients of the pediatric population. Among the cohort of patients, 139 had essential thrombocythemia (ET), 20 had polycythemia vera (PV), and 37 had primary myelofibrosis (PMF). The median age at the time of diagnosis for each disease varied, with 8.8 years for ET, 10 years for PV, and 3.6 years for MF. There was a slight difference in gender prevalence between both gender groups and all three diseases. The presenting symptoms were not mentioned in more than 50% of studies. We found that JAK2 was the most prevalent among all mutations. Both bleeding and thrombosis were present equally in ET, with 9% of cases complicated by bleeding and 9% complicated by thrombosis. Hemorrhagic events did not occur in patients with PV; thrombosis in children with MF was also not found. The progression into AML occurred in two patients with PV and one with ET.

CONCLUSION

Given the rarity of MPNs in pediatrics and their different characteristics compared with adults, we believe there is a need for unique diagnostic criteria to match the different molecular statuses in pediatrics. Based on our review, the incidence of MPN complications in pediatrics, including thrombotic events, hemorrhage, and leukemic transformation, differs from that in adults.

Functionally integrating nanoparticles alleviate deep vein thrombosis in pregnancy and rescue intrauterine growth restriction

There is still unmet demand for effective, safe, and patient-friendly anti-thrombotics to treat deep vein thrombosis (DVT) during pregnancy. Here we first engineer a bioactive amphiphile (TLH) by simultaneously conjugating Tempol and linoleic acid onto low molecular weight heparin (LMWH), which can assemble into multifunctional nanoparticles (TLH NP). In pregnant rats with DVT, TLH NP can target and dissolve thrombi, recanalize vessel occlusion, and eradicate the recurrence of thromboembolism, thereby reversing DVT-mediated intrauterine growth restriction and delayed development of fetuses. Mechanistically, therapeutic effects of TLH NP are realized by inhibiting platelet aggregation, facilitating thrombolysis, reducing local inflammation, attenuating oxidative stress, promoting endothelial repair, and increasing bioavailability. By decorating with a fibrin-binding peptide, targeting efficiency and therapeutic benefits of TLH NP are considerably improved. Importantly, LMWH nanotherapies show no toxicities to the mother and fetus at the dose 10-time higher than the examined therapeutic dosage.

Knockdown of lncRNA XIST Ameliorates IL-1β-Induced Apoptosis of HUVECs and Change of Tissue Factor Level via miR-103a-3p/HMGB1 Axis in Deep Venous Thrombosis by Regulating the ROS/NF-κB Signaling Pathway

Background

The effect of lncRNA X inactive-specific transcript (XIST) inducing cardiovascular diseases on deep vein thrombosis (DVT) and its mechanism has not been reported. In this study, we uncovered the mystery that lncRNA XIST causes DVT with HUVEC dysfunction.

Method

The expression levels of lncRNA XIST and miR-103a-3p were detected by qRT-PCR, and HMGB1 expression was determined by qRT-PCR and western blot. The correlations among the expression levels of lncRNA XIST, miR-103a-3p, and HMGB1 were determined by Spearman's rank-order correlation test. XIST siRNA (si-XIST) was transfected into HUVECs to knock down the intrinsic expression of lncRNA XIST. The influences of si-XIST on interleukin-1 beta- (IL-1β-) treated HUVEC viability and apoptosis and the level of tissue factor (TF) were detected by MTT, flow cytometry, and ELISA kit, respectively. The relationships between lncRNA XIST, miR-103a-3p, and HMGB1 were predicted by the Encyclopedia of RNA Interactomes (ENCORI) database and verified by dual luciferase reporter assay. The effects of lncRNA XIST and miR-103a-3p on HMGB1 expression were detected by qRT-PCR, western blot, and immunofluorescence analysis. The levels of ROS/NF-κB pathway-related proteins were detected to study the regulatory mechanism of lncRNA XIST/miR-103a-3p/HMGB1 on IL-1β-treated HUVECs apoptosis and change of TF level.

Results

The upregulated expression levels of lncRNA XIST and HMGB1 and downregulated level of miR-103a-3p were found in the plasma of DVT patients and IL-1β-treated HUVECs. Si-XIST promoted cell viability and inhibited HUVEC apoptosis and ameliorated the change of TF level triggered by IL-1β. lncRNA XIST sponged miR-103a-3p and miR-103a-3p targeted HMGB1. Si-XIST inhibited the ROS/NF-κB pathway to suppress HUVEC apoptosis and ameliorate the change of TF level induced by IL-1β via the miR-103a-3p/HMGB1 axis.

Conclusion

lncRNA XIST sponged miR-103a-3p improving HMGB1 expression to exacerbate DVT by activating the ROS/NF-κB signaling pathway. Our findings indicated that lncRNA XIST can be used as a potential therapeutic target in DVT.

Immunothrombosis and the Role of Platelets in Venous Thromboembolic Diseases

Venous thromboembolism (VTE) is the third leading cardiovascular cause of death and is conventionally treated with anticoagulants that directly antagonize coagulation. However, recent data have demonstrated that also platelets play a crucial role in VTE pathophysiology. In the current review, we outline how platelets are involved during all stages of experimental venous thrombosis. Platelets mediate initiation of the disease by attaching to the vessel wall upon which they mediate leukocyte recruitment. This process is referred to as immunothrombosis, and within this novel concept inflammatory cells such as leukocytes and platelets directly drive the progression of VTE. In addition to their involvement in immunothrombosis, activated platelets can directly drive venous thrombosis by supporting coagulation and secreting procoagulant factors. Furthermore, fibrinolysis and vessel resolution are (partly) mediated by platelets. Finally, we summarize how conventional antiplatelet therapy can prevent experimental venous thrombosis and impacts (recurrent) VTE in humans.

Assessment of Methemoglobin, Hemoglobin, Ferritin and Lactate dehydrogenase in COVID-19 Patients

Today world is trying to cope with the biggest pandemic caused by Coronavirus disease 2019 (COVID-19). The disease is graded as mild, moderate, serious and critical illness. Very few studies are done with methemoglobin along with other parameters for the assessment of the severity of COVID-19 disease. The objectives of the study were to estimate methemoglobin (Met-Hb), hemoglobin (Hb), ferritin and lactate dehydrogenase (LDH) levels in patients with COVID-19 disease and to investigate the interaction between these parameters and the severity of the disease. This observational study was conducted in three groups of COVID-19 patients- moderate, severe and critical, each group containing 30 patients, between June 2021 and September 2021 in the biochemistry department of a tertiary care hospital. For all patients, Met-Hb, Hb, ferritin, and LDH levels were estimated on the 2nd-3rd day of hospital admission. Patients in the critical group were older and had significantly high values of Met-Hb, ferritin and LDH and significantly low values of Hb (P<0.05). In multivariate ordinal regression analysis, older age (OR-3.08; 95%CI:1.19-7.19;P-0.019), higher values of LDH (OR-8.66; 95%CI:2.53-29.5; P-0.001) and ferritin (OR-3.08; 95%CI:1.09-8.7;P-0.033) were independently associated with severity of the disease. A cut-off value of 410.50 U/L for LDH predicted the severity of the disease with 90% sensitivity and 88.3% specificity. In conclusion, higher levels of LDH and ferritin were related to the severity of the disease in COVID-19 cases. Although Met-Hb showed a minimal increase without any association with severity, it may be an underlying cause of hypoxia that may go unnoticed. So, monitoring of all these parameters should be done at intervals.

Red Cell Distribution Width-to-High-Density Lipoprotein Cholesterol Ratio (RHR): A Promising Novel Predictor for Preoperative Deep Vein Thrombosis in Geriatric Patients with Hip Fracture

Background

Deep vein thrombosis (DVT) is a devastating complication in geriatric patients before hip fracture surgery, and the predictive value of red cell distribution width (RDW) and high-density lipoprotein cholesterol (HDL-C) for DVTs after hip fracture remains to be established. This study aimed to assess the predictive value of RDW, HDL-C, and RDW-to-HDL-C ratio (RHR) in preoperative DVTs screening.

Methods

We retrospectively analyzed the data of geriatric patients (≥65 years old) admitted for hip fracture surgery between 2015 and 2020. The receiver operating characteristic (ROC) curve and related parameters were used to evaluate the predictive value of the biomarkers. Patients were divided into two groups according to the cutoff value of RHR, and propensity score matching (PSM) and subgroup analyses were performed to assess the true correlations between RHR and DVT.

Results

Among 2566 eligible patients included, we identified RDW with the area under ROC curve (AUC) of 0.532, cut-off value of 15.89, specificity of 88.2%, sensitivity of 18.2%, HDL-C with AUC of 0.574, cut-off value of 1.20, specificity of 55.6%, sensitivity of 59.3%, and RHR with AUC of 0.578, cut-off value of 13.45, specificity of 71.3%, sensitivity of 43.4%. RHR (>13.45) was independently associated with 1.54-fold risk (95% CI: 1.11–2.14, P=0.011) of DVTs among the post-PSM cohort. And compared with the counterparts, the relative risk of RHR associated with DVT was higher in the subgroups of aged 65–79 years (1.61 vs 1.45), non-hypoproteinemia (2.70 vs 1.29), non-diabetic (1.58 vs 1.41), non-hypertension (2.40 vs 1.06), ASA score I-II (2.38 vs 1.04), and femoral neck fracture (1.70 vs 1.50).

Conclusion

RDW, HDL-C and RHR were valuable biomarkers in predicting preoperative DVTs in geriatric patients with hip fracture, and RHR would be more efficient in the subgroups of younger age, better medical condition or femoral neck fracture.

Erythrocyte oxidative stress and thrombosis

Thrombosis is a common disorder with a relevant burden of morbidity and mortality worldwide, particularly among elderly patients. Growing evidence demonstrated a direct role of oxidative stress in thrombosis, with various cell types contributing to this process. Among them, erythrocytes produce high quantities of intracellular reactive oxygen species (ROS) by NADPH oxidase activation and haemoglobin autoxidation. Concomitantly, extracellular ROS released by other cells in the blood flow can be uptaken and accumulate within erythrocytes. This oxidative milieu can alter erythrocyte membrane structure, leading to an impaired erythrocyte function, and promoting erythrocytes lysis, binding to endothelial cells, activation of platelet and of coagulation factors, phosphatidylserine exposure and release of microvesicles. Moreover, these abnormal erythrocytes are able to adhere to the vessel wall, contributing to thrombin generation within the thrombus. This process results in accelerated haemolysis and in a hypercoagulable state, in which structurally impaired erythrocytes contribute to increase thrombus size, to reduce its permeability and susceptibility to lysis. However, the wide plethora of mechanisms by which oxidised erythrocytes contribute to thrombosis is not completely elucidated. This review discusses the main biochemical aspects linking erythrocytes, oxidative stress and thrombosis, addressing their potential implication for clinical and therapeutic management.

Antithrombotic and antiplatelet effects of plant-derived compounds: a great utility potential for primary, secondary, and tertiary care in the framework of 3P medicine

Thromboembolism is the third leading vascular disease, with a high annual incidence of 1 to 2 cases per 1000 individuals within the general population. The broader term venous thromboembolism generally refers to deep vein thrombosis, pulmonary embolism, and/or a combination of both. Therefore, thromboembolism can affect both – the central and peripheral veins. Arterial thromboembolism causes systemic ischemia by disturbing blood flow and oxygen supply to organs, tissues, and cells causing, therefore, apoptosis and/or necrosis in the affected tissues. Currently applied antithrombotic drugs used, e.g. to protect affected individuals against ischemic stroke, demonstrate significant limitations. For example, platelet inhibitors possess only moderate efficacy. On the other hand, thrombolytics and anticoagulants significantly increase hemorrhage. Contextually, new approaches are extensively under consideration to develop next-generation antithrombotics with improved efficacy and more personalized and targeted application. To this end, phytochemicals show potent antithrombotic efficacy demonstrated in numerous in vitro, ex vivo, and in vivo models as well as in clinical evaluations conducted on healthy individuals and persons at high risk of thrombotic events, such as pregnant women (primary care), cancer, and COVID-19-affected patients (secondary and tertiary care). Here, we hypothesized that specific antithrombotic and antiplatelet effects of plant-derived compounds might be of great clinical utility in primary, secondary, and tertiary care. To increase the efficacy, precise patient stratification based on predictive diagnostics is essential for targeted protection and treatments tailored to the person in the framework of 3P medicine. Contextually, this paper aims at critical review toward the involvement of specific classes of phytochemicals in antiplatelet and anticoagulation adapted to clinical needs. The paper exemplifies selected plant-derived drugs, plant extracts, and whole plant foods/herbs demonstrating their specific antithrombotic, antiplatelet, and fibrinolytic activities relevant for primary, secondary, and tertiary care. One of the examples considered is antithrombotic and antiplatelet protection specifically relevant for COVID-19-affected patient groups.

Regulation of Neutrophil NADPH Oxidase, NOX2: A Crucial Effector in Neutrophil Phenotype and Function

Reactive oxygen species (ROS), produced by the phagocyte NADPH oxidase, NOX2, are involved in many leukocyte functions. An excessive or inappropriate ROS production can lead to oxidative stress and tissue damage. On the other hand, an absence of ROS production due to a lack of a functional NADPH oxidase is associated with recurrent infections as well as inflammation disorders. Thus, it is clear that the enzyme NADPH oxidase must be tightly regulated. The NOX2 complex bears both membrane and cytosolic subunits. The membrane subunits constitute the flavocytochrome b₅₅₈, consisting of gp91^phox (Nox2) and p22^phox subunits. The cytosolic subunits form a complex in resting cells and are made of three subunits (p47^phox, p40^phox, p67^phox). Upon leukocyte stimulation, the cytosolic subunits and the small GTPase Rac assemble with the flavocytochrome b₅₅₈ in order to make a functional complex. Depending on the stimulus, the NADPH oxidase can assemble either at the phagosomal membrane or at the plasma membrane. Many studies have explored NOX2 activation; however, how this activation is sustained and regulated is still not completely clear. Here we review the multiple roles of NOX2 in neutrophil functions, with a focus on description of its components and their assembly mechanisms. We then explain the role of energy metabolism and phosphoinositides in regulating NADPH oxidase activity. In particular, we discuss: 1) the link between metabolic pathways and NOX2 activity regulation through neutrophil activation and the level of released ROS, and 2) the role of membrane phosphoinositides in controlling the duration of NOX2 activity.

Is Oxidative Stress an Emerging Player in the Thrombosis of Patients with Anti-Phosphatidylethanolamine Autoantibodies?

The detection of anti-phosphatidylethanolamine autoantibodies (aPEs) has been proposed to improve the diagnosis and management of patients presenting clinical manifestations of antiphospholipid syndrome (APS), such as thrombosis, and who are persistently negative for conventional markers. After selecting the most specific ELISA for their detection, we evidenced the interest of aPEs in the exploration of thrombosis when APS conventional markers were negative through a 1-year retrospective study including 1131 consecutive patients routinely tested for aPEs. To validate this result, we assessed aPEs in a newly selected population of 77 patients with unexplained deep vein thrombosis (DVT). With a total prevalence of 19.5%, we confirmed the interest of aPE detection in patients with unexplained DVT who were devoid of other aPLs markers. Since endosomal compartment, a source of ROS production, has been recently identified as the cellular target of aPEs in vitro, we then investigated an association between aPE positivity and reactive oxygen species (ROS) production by measuring the production of thiobarbituric acid-reactive substances. We showed, for the first time, a significant association between aPE positivity and systemic ROS production in patients which led us to hypothesize a new mechanism of action of aPEs in thrombosis through a signaling related to oxidative stress.

The effect of hyperoxia on the hemostasiological status of severely burned patients

The state of the hemostasis system was studied in 9 patients of the middle age group (44 ± 9.94 years) who received thermal trauma on an area of more than 32% (49.4 ± 18.3) of the body surface, accompanied by the development of burn shock. The standard therapy for burn injury was supplemented with HBO sessions. Treatment with hyperbaric oxygen was carried out in pressure chambers BLKS-307, BLKS-307/1. The state of the coagulation, anticoagulant and fibrinolytic links of the hemostasis system, as well as the viscoelastic properties of the blood, were assessed immediately before the HBO session and immediately after it. The total number of comparison pairs was 45. Under the influence of HBO therapy, there was an increase in the activity of antithrombin III (ATIII), protein C (PrS) and a decrease in the viscoelastic properties of blood (p <0.05). Positive deviations in the values of ATIII, Pr C, von Willebrand factor, APTT, prothrombin and thrombin time, fibrinogen, factor XIII, XIIa-dependent fibrinolysis, D-dimers and thromboelastography parameters were revealed. The maximum frequency of their occurrence was recorded for ATIII (95%), the minimum - for the D-dimer (62%). After HBO procedures, undesirable deviations of the hemostatic system parameters were also noted. They were chaotic, were compensated by an increase in the activity of physiological anticoagulants and were not accompanied by complications of a thrombogenic nature. Thus, conducting HBO therapy sessions in the acute period of burn disease increases the activity of physiological anticoagulants and stabilizes the viscoelastic properties of blood. There is a high frequency of occurrence of positive effects of hyperoxia on the components of the hemostasis system. The identification of its undesirable effects indicates the need to monitor the state of the hemostasis system during HBO procedures.

Irradiation of platelets in Transfusion Medicine: risk and benefit judgments

Irradiation of platelet products is generally used to prevent transfusion-associated graft-versus-host disease (TA-GvHD) as well as transfusion-transmitted infections. As an essential prerequisite, gamma-irradiation of blood products prior to transfusion is required in patients who may develop TA-GVHD. Most studies suggest that gamma irradiation has no significant effect on the quality of platelet products; however, more recent studies have shown that the oxidative effects of gamma irradiation can lead to the induction of platelet storage lesion (PSL) and to some extent reduce the efficiency of transfused platelets. As the second widely used irradiation technique, UV-illumination was primarily introduced to reduce the growth of infectious agents during platelet storage, with the advantage that this method can also prevent TA-GvHD. However, the induction of oxidative conditions and platelet pre-activation that lead to PSL is more pronounced after UV-based methods of pathogen reduction. Since these lesions are large enough to clearly affect the post-transfusion platelet recovery and survival, more studies are needed to improve the safety and effectiveness of pathogen reduction technologies (PRTs). Therefore, pointing to other benefits of PRTs, such as preventing TA-GvHD or prolonging the shelf life of products by eliminating the possibility of pathogen growth during storage, does not yet seem to justify their widespread use due to above-mentioned effects. Even for gamma-irradiated platelets, some researchers have suggested that due to decreased 1-hour post-transfusion increments and increased risk of platelet refractoriness, their use should be limited to the patients who may develop TA-GVHD. It is noteworthy that due to the effect of X-rays in preventing TA-GvHD, some recent studies are underway to examine its effects on the quality and effectiveness of platelet products and determine whether X-rays can be used as a more appropriate and cost-effective alternative to gamma radiation. The review presented here provides a detailed description about irradiation-based technologies for platelet products, including their applications, mechanistic features, advantages, and disadvantages.

The effect of combined oral contraceptives containing drospirenone and ethinylestradiol on serum levels of amino acids and acylcarnitines

INTRODUCTION

Metabolome variations have long been associated with normal hormonal fluctuations, and similar effects, related to the use of early generation synthetic hormones as a means of contraception, have also been identified.

OBJECTIVE

We investigated the serum amino acid and acylcarnitine profiles induced by the use of combined oral contraceptives (COCs) consisting of Ethinylestradiol (EE) and a 4th generation progestin, Drospirenone (DRSP).

METHOD

Gas chromatography mass spectrometry and liquid chromatography with tandem mass spectrometry was used to identify and quantify the serum amino acids and acyl carnitine levels in 24 controls, 25 DRSP/20EE users and 26 DRSP/30EE users.

RESULTS

Of the 26 amino acid compounds measured, 13 showed significant variations in abundance between the control and COC user groups. Although none of the 21 acylcarnitine compounds detected were statistically significant with regards to group variations, a trend, related the EE concentration, was observed. The detected metabolome disparities corresponded to that identified for earlier generation COCs, all pointing toward increased oxidative stress levels in the user groups.

CONCLUSION

These findings suggest that the clinical complications associated with these COCs could, to some extent, be alleviated by the simultaneous use of antioxidants. The study also highlights the role that targeted metabolomics could play in the elucidation of the underlying mechanisms of drug-induced severe effects.

Hypercoagulable State in COPD-A Comprehensive Literature Review

Chronic Obstructive Pulmonary Disease (COPD) is a chronic inflammatory disease with multisystemic manifestations. Studies either held on stable disease patients or during exacerbations have demonstrated that COPD is strongly related to venous thromboembolism and cardiovascular events. The aim of the present review of the literature was to provide an in-depth overview regarding the alterations of coagulation factors and prothrombotic changes generated in patients with stable COPD and during COPD exacerbations.

Neutrophil Extracellular Traps in Fatal COVID-19-Associated Lung Injury

An excess formation of neutrophil extracellular traps (NETs), previously shown to be strongly associated with cytokine storm and acute respiratory distress syndrome (ARDS) with prevalent endothelial dysfunction and thrombosis, has been postulated to be a central factor influencing the pathophysiology and clinical presentation of severe COVID-19. A growing number of serological and morphological evidence has added to this assumption, also in regard to potential treatment options. In this study, we used immunohistochemistry and histochemistry to trace NETs and their molecular markers in autopsy lung tissue from seven COVID-19 patients. Quantification of key immunomorphological features enabled comparison with non-COVID-19 diffuse alveolar damage. Our results strengthen and extend recent findings, confirming that NETs are abundantly present in seriously damaged COVID-19 lung tissue, especially in association with microthrombi of the alveolar capillaries. In addition, we provide evidence that low-density neutrophils (LDNs), which are especially prone to NETosis, contribute substantially to COVID-19-associated lung damage in general and vascular blockages in particular.

Insights on the mechanisms of action of ozone in the medical therapy against COVID-19

An increasing amount of reports in the literature is showing that medical ozone (O₃) is used, with encouraging results, in treating COVID-19 patients, optimizing pain and symptoms relief, respiratory parameters, inflammatory and coagulation markers and the overall health status, so reducing significantly how much time patients underwent hospitalization and intensive care. To date, aside from mechanisms taking into account the ability of O₃ to activate a rapid oxidative stress response, by up-regulating antioxidant and scavenging enzymes, no sound hypothesis was addressed to attempt a synopsis of how O₃ should act on COVID-19. The knowledge on how O₃ works on inflammation and thrombosis mechanisms is of the utmost importance to make physicians endowed with new guns against SARS-CoV2 pandemic. This review tries to address this issue, so to expand the debate in the scientific community.

AGEs/RAGE blockade downregulates Endothenin-1 (ET-1), mitigating Human Umbilical Vein Endothelial Cells (HUVEC) injury in deep vein thrombosis (DVT)

This study is aimed at identifying the roles of AGE/RAGE and ET-1 in deep vein thrombosis (DVT). Advanced glycation end products (AGEs) in glycated human serum albumin (M-HSA) were detected by ELISA. The viability of HUVECs was examined by CCK-8 assay. Flow cytometry was performed to detect cell apoptosis, followed by ELISA for the detection of inflammatory cytokine level and oxidative stress level in HUVECs. Immunofluorescence was performed to detect ET-1 and eNOS expression. The expression of specific proteins was assayed by western blot. As a result, decreased HUVEC viability was observed after stimulation with M-HSA, whereas RAGE inhibitor improved it. Cell apoptosis showed the opposite trend. Additionally, M-HSA-induced inflammatory cytokine release and oxidative stress of HUVECs were both alleviated by RAGE inhibitor. RAGE inhibitor also increased the levels of NO and eNOS while decreasing the level of ET-1 in M-HSA-stimulated HUVECs. Furthermore, decreased protein expression of Bax, cleaved-caspase3, RAGE, p65, ET-1 and iNOS was observed after treatment with RAGE inhibitor, in addition to increased protein expression of Bcl-2 and eNOS. In conclusion, blocking AGE/RAGE pathway downregulates ET-1, thereby mitigating HUVEC damage in DVT.

Oxidative Stress Triggers Defective Autophagy in Endothelial Cells: Role in Atherothrombosis Development

Atherothrombosis, a multifactorial and multistep artery disorder, represents one of the main causes of morbidity and mortality worldwide. The development and progression of atherothrombosis is closely associated with age, gender and a complex relationship between unhealthy lifestyle habits and several genetic risk factors. The imbalance between oxidative stress and antioxidant defenses is the main biological event leading to the development of a pro-oxidant phenotype, triggering cellular and molecular mechanisms associated with the atherothrombotic process. The pathogenesis of atherosclerosis and its late thrombotic complications involve multiple cellular events such as inflammation, endothelial dysfunction, proliferation of vascular smooth muscle cells (SMCs), extracellular matrix (ECM) alterations, and platelet activation, contributing to chronic pathological remodeling of the vascular wall, atheromatous plague formation, vascular stenosis, and eventually, thrombus growth and propagation. Emerging studies suggest that clotting activation and endothelial cell (EC) dysfunction play key roles in the pathogenesis of atherothrombosis. Furthermore, a growing body of evidence indicates that defective autophagy is closely linked to the overproduction of reactive oxygen species (ROS) which, in turn, are involved in the development and progression of atherosclerotic disease. This topic represents a large field of study aimed at identifying new potential therapeutic targets. In this review, we focus on the major role played by the autophagic pathway induced by oxidative stress in the modulation of EC dysfunction as a background to understand its potential role in the development of atherothrombosis.

Reactive Oxygen Species and Their Involvement in Red Blood Cell Damage in Chronic Kidney Disease

Reactive oxygen species (ROS) released in cells are signaling molecules but can also modify signaling proteins. Red blood cells perform a major role in maintaining the balance of the redox in the blood. The main cytosolic protein of RBC is hemoglobin (Hb), which accounts for 95-97%. Most other proteins are involved in protecting the blood cell from oxidative stress. Hemoglobin is a major factor in initiating oxidative stress within the erythrocyte. RBCs can also be damaged by exogenous oxidants. Hb autoxidation leads to the generation of a superoxide radical, of which the catalyzed or spontaneous dismutation produces hydrogen peroxide. Both oxidants induce hemichrome formation, heme degradation, and release of free iron which is a catalyst for free radical reactions. To maintain the redox balance, appropriate antioxidants are present in the cytosol, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and peroxiredoxin 2 (PRDX2), as well as low molecular weight antioxidants: glutathione, ascorbic acid, lipoic acid, α-tocopherol, β-carotene, and others. Redox imbalance leads to oxidative stress and may be associated with overproduction of ROS and/or insufficient capacity of the antioxidant system. Oxidative stress performs a key role in CKD as evidenced by the high level of markers associated with oxidative damage to proteins, lipids, and DNA in vivo. In addition to the overproduction of ROS, a reduced antioxidant capacity is observed, associated with a decrease in the activity of SOD, GPx, PRDX2, and low molecular weight antioxidants. In addition, hemodialysis is accompanied by oxidative stress in which low-biocompatibility dialysis membranes activate phagocytic cells, especially neutrophils and monocytes, leading to a respiratory burst. This review shows the production of ROS under normal conditions and CKD and its impact on disease progression. Oxidative damage to red blood cells (RBCs) in CKD and their contribution to cardiovascular disease are also discussed.

Oxidative status and antioxidant enzyme levels in deep venous thrombosis patients

Deep vein thrombosis (DVT), a subset of venous thromboembolism (VTE), is a major preventable cause of morbidity and mortality worldwide. We aim to investigate changes in oxidative injury markers and the levels of antioxidant parameters in DVT patients. 50 DVT patients who were admitted to the cardiovascular surgery clinic with acute (<2 weeks) or chronic (≥4 weeks) DVT and 100 healthy individuals were included. As oxidative injury marker malondialdehyde and the antioxidant parameters including reduced glutathione, glutathione peroxidase, catalase, and superoxide dismutase were analysed in the collected peripheral blood samples. Demographic characteristics of the acute and chronic DVT patients were similar (P>0.05). In all DVT patients having thrombosis in the distal and proximal leg veins the mean malondialdehyde and glutathione peroxidase activity were significantly increased, but superoxide dismutase activity significantly decreased, compared to the healthy controls (P<0.05). No difference was observed between distal and proximal DVT patient groups. The increased levels of malondialdehyde in our study is considered to result from the significant decrease in the antioxidant enzyme activity of superoxide dismutase. Furthermore, we are of the opinion that the increased levels of glutathione peroxidase enzyme activity observed in all patients could not compensate the reduction in the superoxide dismutase activity, thereby being insufficient in preventing the increase in the malondialdehyde levels.

Rho GTPase regulation of reactive oxygen species generation and signalling in platelet function and disease

Platelets are master regulators and effectors of haemostasis with increasingly recognized functions as mediators of inflammation and immune responses. The Rho family of GTPase members Rac1, Cdc42 and RhoA are known to be major components of the intracellular signalling network critical to platelet shape change and morphological dynamics, thus playing a major role in platelet spreading, secretion and thrombus formation. Initially linked to the regulation of actomyosin contraction and lamellipodia formation, recent reports have uncovered non-canonical functions of platelet RhoGTPases in the regulation of reactive oxygen species (ROS), where intrinsically generated ROS modulate platelet function and contribute to thrombus formation. Platelet RhoGTPases orchestrate oxidative processes and cytoskeletal rearrangement in an interconnected manner to regulate intracellular signalling networks underlying platelet activity and thrombus formation. Herein we review our current knowledge of the regulation of platelet ROS generation by RhoGTPases and their relationship with platelet cytoskeletal reorganization, activation and function.

Incidence and risk factors of venous thromboembolism in ANCA-associated vasculitis: a metaanalysis and metaregression

The incidence of venous thromboembolism (VTE) in ANCA-associated vasculitis patients varies in different populations. Moreover, the risk factors for VTE in these patients are poorly described due to the small number of events. Ovid MEDLINE, EMBASE, and the Cochrane Library were searched for eligible articles. The inclusion criteria included observational studies that enrolled patients age ≥ 18 years diagnosed with ANCA-associated vasculitis. The incidence of VTE is the outcome of interest. Of 1362 citations, a total of 21 studies (n = 4422) dated from 2006 to 2019 were included in the systematic review. The mean age was 54.2 ± 4.0 years. Most were male (52.0%) and Caucasian (80.9%). With a mean follow-up duration of 5.2 ± 2.8 years, the pooled incidence of VTE in ANCA-associated vasculitis patients was 12.4% (95% CI, 8.8-17.2). Of these, 63.4% (95% CI, 57.3-69.1) had deep vein thrombosis and 26.3% (95% CI, 17.6-37.4) had pulmonary embolism. Recurrent VTE occurred in 10.0% (95% CI, 5.2-18.6). From the metaregression adjusted for age, sex, and ethnicity; positive MPO-ANCA, increasing Birmingham Vasculitis Activity Score at time of vasculitis diagnosis, and presence of renal involvement were positively associated with increased VTE events. Positive PR3-ANCA profile was inversely associated with increased VTE events. Increasing follow-up duration was not associated with increased VTE events. VTE in ANCA-associated vasculitis is common. Positive MPO-ANCA, increasing vasculitis activity, and presence of renal involvement were significant risk factors for VTE while positive PR3-ANCA was inversely associated with increased VTE. Key Points • Venous thromboembolism (VTE) is common in ANCA-associated vasculitis with a pooled incidence of 12.4% • Deep vein thrombosis accounts for two-third of total VTE cases • Positive MPO-ANCA profile, higher disease activity at ANCA-associated vasculitis diagnosis, and renal involvement are risk factors for VTE • Positive PR3-ANCA profile is protective factor for VTE.

Preventing the development of severe COVID-19 by modifying immunothrombosis

BACKGROUND

COVID-19-associated acute respiratory distress syndrome (ARDS) is associated with significant morbidity and high levels of mortality. This paper describes the processes involved in the pathophysiology of COVID-19 from the initial infection and subsequent destruction of type II alveolar epithelial cells by SARS-CoV-2 and culminating in the development of ARDS.

MAIN BODY

The activation of alveolar cells and alveolar macrophages leads to the release of large quantities of proinflammatory cytokines and chemokines and their translocation into the pulmonary vasculature. The presence of these inflammatory mediators in the vascular compartment leads to the activation of vascular endothelial cells platelets and neutrophils and the subsequent formation of platelet neutrophil complexes. These complexes in concert with activated endothelial cells interact to create a state of immunothrombosis. The consequence of immunothrombosis include hypercoagulation, accelerating inflammation, fibrin deposition, migration of neutrophil extracellular traps (NETs) producing neutrophils into the alveolar apace, activation of the NLRP3 inflammazome, increased alveolar macrophage destruction and massive tissue damage by pyroptosis and necroptosis Therapeutic combinations aimed at ameliorating immunothrombosis and preventing the development of severe COVID-19 are discussed in detail.

The emerging role of neutrophil extracellular traps in severe acute respiratory syndrome coronavirus 2 (COVID-19)

The novel coronavirus SARS-CoV-2 causes COVID-19, a highly pathogenic viral infection threatening millions. The majority of the individuals infected are asymptomatic or mildly symptomatic showing typical clinical signs of common cold. However, approximately 20% of the patients can progress to acute respiratory distress syndrome (ARDS), evolving to death in about 5% of cases. Recently, angiotensin-converting enzyme 2 (ACE2) has been shown to be a functional receptor for virus entry into host target cells. The upregulation of ACE2 in patients with comorbidities may represent a propensity for increased viral load and spreading of infection to extrapulmonary tissues. This systemic infection is associated with higher neutrophil to lymphocyte ratio in infected tissues and high levels of pro-inflammatory cytokines leading to an extensive microthrombus formation with multiorgan failure. Herein we investigated whether SARS-CoV-2 can stimulate extracellular neutrophils traps (NETs) in a process called NETosis. We demonstrated for the first time that SARS-CoV-2 in fact is able to activate NETosis in human neutrophils. Our findings indicated that this process is associated with increased levels of intracellular Reactive Oxygen Species (ROS) in neutrophils. The ROS-NET pathway plays a role in thrombosis formation and our study suggest the importance of this target for therapy approaches against disease.

Factors Affecting the Formation and Treatment of Thrombosis by Natural and Synthetic Compounds

Venous thromboembolism (VTE) refers to deep vein thrombosis (DVT), whose consequence may be a pulmonary embolism (PE). Thrombosis is associated with significant morbidity and mortality and is the third most common cardiovascular disease after myocardial infarction and stroke. DVT is associated with the formation of a blood clot in a deep vein in the body. Thrombosis promotes slowed blood flow, hypoxia, cell activation, and the associated release of many active substances involved in blood clot formation. All thrombi which adhere to endothelium consist of fibrin, platelets, and trapped red and white blood cells. In this review, we summarise the impact of various factors affecting haemostatic disorders leading to blood clot formation. The paper discusses the causes of thrombosis, the mechanism of blood clot formation, and factors such as hypoxia, the involvement of endothelial cells (ECs), and the activation of platelets and neutrophils along with the effects of bacteria and reactive oxygen species (ROS). Mechanisms related to the action of anticoagulants affecting coagulation factors including antiplatelet drugs have also been discussed. However, many aspects related to the pathogenesis of thrombosis still need to be clarified. A review of the drugs used to treat and prevent thrombosis and natural anticoagulants that occur in the plant world and are traditionally used in Far Eastern medicine has also been carried out.

Application of methylene blue -vitamin C -N-acetyl cysteine for treatment of critically ill COVID-19 patients, report of a phase-I clinical trial

COVID-19 is a global catastrophic event that causes severe acute respiratory syndrome. The mechanism of the disease remains unclear, and hypoxia is one of the main complications. There is no currently approved protocol for treatment. The microbial threat as induced by COVID-19 causes the activation of macrophages to produce a huge amount of inflammatory molecules and nitric oxide (NO). Activation of macrophages population into a pro-inflammatory phenotype induces a self-reinforcing cycle. Oxidative stress and NO contribute to this cycle, establishing a cascade inflammatory state that can kill the patient. Interrupting this vicious cycle by a simple remedy may save critical patients' lives. Nitrite, nitrate (the metabolites of NO), methemoglobin, and prooxidant-antioxidant-balance levels were measured in 25 ICU COVID-19 patients and 25 healthy individuals. As the last therapeutic option, five patients were administered methylene blue-vitamin C-N-acetyl Cysteine (MCN). Nitrite, nitrate, methemoglobin, and oxidative stress were significantly increased in patients in comparison to healthy individuals. Four of the five patients responded well to treatment. In conclusion, NO, methemoglobin and oxidative stress may play a central role in the pathogenesis of critical COVID-19 disease. MCN treatment seems to increase the survival rate of these patients. Considering the vicious cycle of macrophage activation leading to deadly NO, oxidative stress, and cytokine cascade syndrome; the therapeutic effect of MCN seems to be reasonable. Accordingly, a wider clinical trial has been designed. It should be noted that the protocol is using the low-cost drugs which the FDA approved for other diseases. TRIAL REGISTRATION NUMBER: NCT04370288.