Microparticles in red cell concentrates prime polymorphonuclear neutrophils and cause acute lung injury in a two-event mouse model

Extracellular vesicles in fresh frozen plasma and cryoprecipitate: Impact on in vitro endothelial cell viability

BACKGROUND

Transfusion-related acute lung injury (TRALI) remains a major contributor to transfusion-associated mortality. While the pathogenesis of TRALI remains unclear, there is evidence of a role for blood components. We therefore investigated the potential effects of fresh frozen plasma (FFP), cryoprecipitate, and extracellular vesicles (EVs) derived from these blood components, on the viability of human lung microvascular endothelial cells (HLMVECs) in vitro.

METHODS

EVs were isolated from FFP and cryoprecipitate using size-exclusion chromatography and characterized by nanoparticle tracking analysis, western blotting, and transmission electron microscopy. The potential effects of these blood components and their EVs on HLMVEC viability (determined by trypan blue exclusion) were examined in the presence and absence of neutrophils, either with or without prior treatment of HLMVECs with LPS.

RESULTS

EVs isolated from FFP and cryoprecipitate displayed morphological and biochemical properties conforming to latest international criteria. While FFP, cryoprecipitate, and EVs derived from FFP, each reduced HLMVEC viability, no effect was observed for EVs derived from cryoprecipitate.

CONCLUSION

Our findings demonstrate clear differences in the effects of FFP, cryoprecipitate, and their respective EVs on HLMVEC viability in vitro. Examination of the mechanisms underlying these differences may lead to an improved understanding of the factors that promote development of TRALI.

Adverse effects of microparticles on transfusion of stored red blood cell concentrates

BACKGROUND

Systemic and pulmonary coagulopathy and inflammation are important characteristics of transfusion-related acute lung injury (TRALI). Whether microparticles that accumulate in transfused red blood cell concentrates (RBCs) have proinflammatory and procoagulant potential and contribute to adverse reactions of RBC transfusions is unclear.

AIM

To investigate the ability of microparticles in stored RBCs to promote thrombin generation and induce human pulmonary microvascular endothelial cell (HMVEC) activation and damage.

METHODS

The number and size of microparticles were determined by flow cytometric and nanoparticle tracking analyses, respectively. Thrombin generation and the intrinsic coagulation pathway were assayed by a calibrated automated thrombogram and by measuring activated partial thromboplastin time (aPTT), respectively. The expression of ICAM-1 and the release of cytokines by endothelial cells were detected by flow cytometric analyses. HMVEC damage was assessed by incubating lipopolysaccharide-activated endothelial cells with MP-primed polymorphonuclear neutrophils (PMNs).

RESULTS

The size of the microparticles in the RBC supernatant was approximately 100-300 nm. Microparticles promoted thrombin generation in a dose-dependent manner and the aPTT was shortened. Depleting microparticles from the supernatant of RBCs stored for 35 days by either filtration or centrifugation significantly decreased the promotion of thrombin generation. The expression of ICAM-1 on HMVECs was increased significantly by incubation with isolated microparticles. Furthermore, microparticles induced the release of interleukin-6 (IL-6) and interleukin-8 (IL-8) from HMVECs. Microparticles induced lipopolysaccharide-activated HMVEC damage by priming PMNs, but this effect was prevented by inhibiting the PMNs respiratory burst with apocynin.

CONCLUSION

Microparticles in stored RBCs promote thrombin generation, HMVEC activation and damage which may be involved in TRALI development.

Crosstalk between neutrophil extracellular traps and immune regulation: insights into pathobiology and therapeutic implications of transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-associated death, occurring during or within 6 hours after transfusion. Reports indicate that TRALI can be categorized as having or lacking acute respiratory distress syndrome (ARDS) risk factors. There are two types of TRALI in terms of its pathogenesis: antibody-mediated and non-antibody-mediated. The key initiation steps involve the priming and activation of neutrophils, with neutrophil extracellular traps (NETs) being established as effector molecules formed by activated neutrophils in response to various stimuli. These NETs contribute to the production and release of reactive oxygen species (ROS) and participate in the destruction of pulmonary vascular endothelial cells. The significant role of NETs in TRALI is well recognized, offering a potential pathway for TRALI treatment. Moreover, platelets, macrophages, endothelial cells, and complements have been identified as promoters of NET formation. Concurrently, studies have demonstrated that the storage of platelets and concentrated red blood cells (RBC) can induce TRALI through bioactive lipids. In this article, recent clinical and pre-clinical studies on the pathophysiology and pathogenesis of TRALI are reviewed to further illuminate the mechanism through which NETs induce TRALI. This review aims to propose new therapeutic strategies for TRALI, with the hope of effectively improving its poor prognosis.

Red Blood Cell-Derived Extracellular Vesicles: An Overview of Current Research Progress, Challenges, and Opportunities

Red blood cell-derived extracellular vesicles (RBC EVs) are small, spherical fragments released from red blood cells. These vesicles, similar to EVs derived from other cell types, are crucial for intercellular communication processes and have been implicated in various physiological and pathological processes. The diagnostic and therapeutic potential of RBC EVs has garnered increasing attention in recent years, revealing their valuable role in the field of medicine. In this review, we aim to provide a comprehensive analysis of the current research status of RBC EVs. We summarize existing studies and highlight the progress made in understanding the characteristics and functions of RBC EVs, with a particular focus on their biological roles in different diseases. We also discuss their potential utility as diagnostic and prognostic biomarkers in diseases and as vectors for drug delivery. Furthermore, we emphasize the need for further research to achieve selective purification of RBC EVs and unravel their heterogeneity, which will allow for a deeper understanding of their diverse functions and exploration of their potential applications in diagnostics and therapeutics.

Extracellular vesicles: effectors of transfusion-related acute lung injury

Respiratory transfusion reactions represent some of the most severe adverse reactions related to receiving blood products. Of those, transfusion-related acute lung injury (TRALI) is associated with elevated morbidity and mortality. TRALI is characterized by severe lung injury associated with inflammation, pulmonary neutrophil infiltration, lung barrier leak, and increased interstitial and airspace edema that cause respiratory failure. Presently, there are few means of detecting TRALI beyond clinical definitions based on physical examination and vital signs or preventing/treating TRALI beyond supportive care with oxygen and positive pressure ventilation. Mechanistically, TRALI is thought to be mediated by the culmination of two successive proinflammatory hits, which typically comprise a recipient factor (1st hit-e.g., systemic inflammatory conditions) and a donor factor (2nd hit-e.g., blood products containing pathogenic antibodies or bioactive lipids). An emerging concept in TRALI research is the contribution of extracellular vesicles (EVs) in mediating the first and/or second hit in TRALI. EVs are small, subcellular, membrane-bound vesicles that circulate in donor and recipient blood. Injurious EVs may be released by immune or vascular cells during inflammation, by infectious bacteria, or in blood products during storage, and can target the lung upon systemic dissemination. This review assesses emerging concepts such as how EVs: 1) mediate TRALI, 2) represent targets for therapeutic intervention to prevent or treat TRALI, and 3) serve as biochemical biomarkers facilitating TRALI diagnosis and detection in at-risk patients.

Astaxanthin ameliorates lipopolysaccharide-induced acute lung injury via inhibition of inflammatory reactions and modulation of the SOCS3/JAK2/STAT3 signaling pathways in mice

The results showed that astaxanthin had a protective effect on LPS-induced acute lung injury in mice, and its protective mechanism was through activating the SOCS3/JAK2/STAT3 signaling pathway.

Extracellular Vesicles: A New Paradigm for Cellular Communication in Perioperative Medicine, Critical Care, and Pain Management

Extracellular vesicles (EVs) play critical roles in many health and disease states, including ischemia, inflammation, and pain, which are major concerns in the perioperative period and in critically ill patients. EVs are functionally active, nanometer-sized, membrane-bound vesicles actively secreted by all cells. Cell signaling is essential to physiological and pathological processes, and EVs have recently emerged as key players in intercellular communication. Recent studies in EV biology have improved our mechanistic knowledge of the pathophysiological processes in perioperative and critical care patients. Studies also show promise in using EVs in novel diagnostic and therapeutic clinical applications. This review considers the current advances and gaps in knowledge of EVs in the areas of ischemia, inflammation, pain, and in organ systems that are most relevant to anesthesiology, perioperative medicine, critical care, and pain management. We expect the reader will better understand the relationship between EVs and perioperative and critical care pathophysiological states and their potential use as novel diagnostic and therapeutic modalities.

Extracellular vesicles in acute respiratory distress syndrome: Recent developments from bench to bedside

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), characterized by a large number of inflammatory cell aggregation and alveolar cell damage in pathophysiology, have extremely high morbidity and mortality in critically ill patients. In recent years, more and more studies have found that there are abundant extracellular vesicles (EVs) in animal models and patients with ALI/ARDS, and they play a critical role in the pathogenesis of lung injury. Clarifying the mechanisms of EVs in lung injury is of great significance in the diagnosis and treatment of ALI/ARDS. In this review, we will summarize the recent findings on the roles of EVs derived from different cells in ALI/ARDS, along with the formation, function, and related effects of EVs, and explore their potential clinical application for the diagnosis and treatment of ALI/ARDS.

Protective Effects of Pterostilbene on Lipopolysaccharide-Induced Acute Lung Injury in Mice by Inhibiting NF-κB and Activating Nrf2/HO-1 Signaling Pathways

Pterostilbene (PTER) is a kind of stilbene compound with biological activity isolated from plants such as red sandalwood, blueberry and grape. It has anti-tumor, anti-bacterial, anti-oxidation and other pharmacological activities. However, the underlying mechanism of the protective effect of PTER on lipopolysaccharide (LPS)-induced acute lung injury (ALI) remained not clarified. In this study, LPS was used to establish a mouse model of ALI. Bronchoalveolar lavage fluid (BALF) was collected for inflammatory cells, and the wet-to-dry weight ratio of the lungs was measured. The activities of myeloperoxidase (MPO), antioxidant indexes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and oxidation index such as malondialdehyde (MDA) in lung tissues of mice were measured by the corresponding kits. The levels of Cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), TNF-α, IL-6 and IL-1β in lung tissues of mice were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The activities of Nrf2, HO-1, p-p65 and p-IκB were determined by western blotting. The results showed that the model of LPS-induced ALI was successfully replicated, and it was found that PTER could significantly improve the pathological degree of ALI such as sustained the integrity of the lung tissue structure, alleviated pulmonary interstitial edema and alveolar wall thickening, reduced infiltrated inflammatory cells. PTER could decrease the number of inflammatory cells and obviously inhibit the increase of W/D ratio caused by LPS. PTER could also significantly reduce LPS-induced MPO and MDA, and increase LPS-decreased SOD, CAT and GSH-Px in the lungs. In addition, it was also found that PTER has the ability to decrease LPS-induced production of COX-2, iNOS, TNF-α, IL-6 and IL-1β. The underlying mechanism involved in the protective effect of PTER on ALI were via activating Nrf2 and HO-1, and inhibiting the phosphorylation of p65 and IκB. These results suggested that PTER can protect LPS-induced ALI in mice by inhibiting inflammatory response and oxidative stress, which provided evidence that PTER may be a potential therapeutic candidate for LPS-induced ALI intervention.

Inflammasome activation in acute lung injury

Inflammasomes are multiprotein complexes tasked with sensing endogenous or exogenous inflammatory signals and integrating this signal into a downstream response. Inflammasome activation has been implicated in a variety of pulmonary diseases, including pulmonary hypertension, bacterial pneumonia, COPD, and asthma. Of increasing interest is the contribution of inflammasome activation in the context of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Inflammasome activation in both the lung parenchyma and resident immune cells generates intereukin-1β (IL-1β) and IL-18, both of which drive the cascade of lung inflammation forward. Blockade of these responses has been shown to be beneficial in animal models and is a focus of translational research in the field. In this review, we will discuss the assembly and regulation of inflammasomes during lung inflammation, highlighting therapeutically viable effector steps. We will examine the importance of IL-1β and IL-18, two key products of inflammasome activation, in ALI, as well as the contribution of the pulmonary endothelial cell to this process. Finally, we will explore translational research moving toward anti-inflammasome therapies for ALI/ARDS and speculate toward future directions for the field.

Synergistic effects of EMPs and PMPs on pulmonary vascular leakage and lung injury after ischemia/reperfusion

Background

Vascular leakage is an important pathophysiological process of critical conditions such as shock and ischemia–reperfusion (I/R)-induced lung injury. Microparticles (MPs), including endothelial cell-derived microparticles (EMPs), platelet-derived microparticles (PMPs) and leukocyte-derived microparticles (LMPs), have been shown to participate in many diseases. Whether and which of these MPs take part in pulmonary vascular leakage and lung injury after I/R and whether these MPs have synergistic effect and the underlying mechanism are not known.

Methods

Using hemorrhage/transfusion (Hemo/Trans) and aorta abdominalis occlusion-induced I/R rat models, the role of EMPs, PMPs and LMPs and the mechanisms in pulmonary vascular leakage and lung injury were observed.

Results

The concentrations of EMPs, PMPs and LMPs were significantly increased after I/R. Intravenous administration of EMPs and PMPs but not LMPs induced pulmonary vascular leakage and lung injury. Furthermore, EMPs induced pulmonary sequestration of platelets and promoted more PMPs production, and played a synergistic effect on pulmonary vascular leakage. MiR-1, miR-155 and miR-542 in EMPs, and miR-126 and miR-29 in PMPs, were significantly increased after hypoxia/reoxygenation (H/R). Of which, inhibition of miR-155 in EMPs and miR-126 in PMPs alleviated the detrimental effects of EMPs and PMPs on vascular barrier function and lung injury. Overexpression of miR-155 in EMPs down-regulated the expression of tight junction related proteins such as ZO-1 and claudin-5, while overexpression of miR-126 up-regulated the expression of caveolin-1 (Cav-1), the trans-cellular transportation related protein such as caveolin-1 (Cav-1). Inhibiting EMPs and PMPs production with blebbistatin (BLE) and amitriptyline (AMI) alleviated I/R induced pulmonary vascular leakage and lung injury.

Conclusions

EMPs and PMPs contribute to the pulmonary vascular leakage and lung injury after I/R. EMPs mediate pulmonary sequestration of platelets, producing more PMPs to play synergistic effect. Mechanically, EMPs carrying miR-155 that down-regulates ZO-1 and claudin-5 and PMPs carrying miR-126 that up-regulates Cav-1, synergistically mediate pulmonary vascular leakage and lung injury after I/R.

Graphic abstract

Cell-Derived Microparticles in Blood Products from Thalassemic Blood Donors

OBJECTIVE

To determine the number of cell-derived microparticles (MPs) in blood products obtained from donors who have thalassemia.

METHODS

Packed red blood cells (PRBCs), plasma, and platelet concentrate (PC) were prepared according to routine procedures. We used flow cytometry to quantitate the concentration of MPs.

RESULTS

The results of a comparison of MP levels in unprocessed whole blood showed that the concentration of all MPs in the donors without thalassemia trait (n = 255) was higher than in donors with thalassemia trait (n = 70). After processing, increased concentrations of MPs were documented in both groups. Among the blood components, PRBC showed higher platelet-derived MP concentrations in donors with thalassemia than in donors without thalassemia. However, PC showed higher concentrations of total MPs in donors without thalassemia than in donors with that condition.

CONCLUSIONS

Our results suggest little influence of thalassemia-trait status on changes in MP concentrations in blood components.

Red-blood-cell manufacturing methods and storage solutions differentially induce pulmonary cell activation

Background and Objectives

Red‐blood‐cell (RBC) transfusion is associated with lung injury, which is further exacerbated by mechanical ventilation. Manufacturing methods of blood products differ globally and may play a role in the induction of pulmonary cell activation through alteration of the immunomodulatory property of the products. Here, the effect of different manufacturing methods on pulmonary cell activation was investigated in an in vitro model of mechanical ventilation.

Materials and Methods

Pulmonary type II cells were incubated with supernatant from fresh and old RBC products obtained via whole blood filtration (WBF), red cell filtration (RCF), apheresis‐derived (AD) or whole blood‐derived (WBD) methods. Lung cells were subjected to 25% stretch for 24 h. Controls were non‐stretched or non‐incubated cells.

Results

Fresh but not old AD products and WBF products induce lung cell production of pro‐inflammatory cytokines and chemokines, which was not observed with WBD or RCF products. Effects were associated with an increased amount of platelet‐derived vesicles and an increased thrombin‐generating capacity. Mechanical stretching of lung cells induced more severe cell injury compared to un‐stretched controls, including alterations in the cytoskeleton, which was further augmented by incubation with AD products. In all read‐out parameters, RCF products seemed to induce less injury compared to the other products.

Conclusions

Our findings show that manufacturing methods of RBC products impact pulmonary cell activation, which may be mediated by the generation of vesicles in the product. We suggest RBC manufacturing method may be an important factor in understanding the association between RBC transfusion and lung injury.

The contribution of oxidative stress to platelet senescence during storage

BACKGROUND

Platelets for transfusion become senescent and dysfunctional during storage, resulting in a markedly short shelf life (5 days). We hypothesized that oxidative stress might account for this decline.

STUDY DESIGN AND METHODS

Human platelets were treated with or without antioxidants before storage, and samples were collected and analyzed at different time points. Platelet senescence was determined by senescence-associated β-galactosidase assay, and senescence-related platelet qualities were also analyzed.

RESULTS

Sign of senescence became evident after Day 3 and continued to increase over time. We also found that chemical induction of platelet activation did not affect senescence level, whereas apoptosis inducers showed a stimulative effect on platelet senescence. Moreover, this effect was not prevented by a pan-caspase inhibitor. Meanwhile, cellular and mitochondrial reactive oxygen species were found elevated during storage, and treatments with antioxidants successfully prevented this increase and also mitigated senescence levels of stored platelets. Finally, resveratrol, a natural antioxidant, was utilized as a novel storage additive to safely extend platelet shelf time. We showed that the addition of resveratrol efficiently postponed platelet senescence and ameliorated platelet storage lesion.

CONCLUSIONS

Platelets during storage became senescent and dysfunctional over time, and we found that oxidative stress might account for this decline. The addition of antioxidants effectively postponed senescence and ameliorated platelet storage lesion, which might provide a valuable reference to future platelet storage methodologies.

Extracellular vesicles in lung health, disease, and therapy

Both physiological homeostasis and pathological disease processes in the lung typically result from complex, yet coordinated multicellular responses that are synchronized via paracrine and endocrine intercellular communication pathways. Of late, extracellular vesicles have emerged as important information shuttles that can coordinate and disseminate homeostatic and disease signals. In parallel, extracellular vesicles in biological fluids such as sputum, mucus, epithelial lining fluid, edema fluid, the pulmonary circulation, pleural fluid, and lymphatics have emerged as promising candidate biomarkers for diagnosis and prognosis in lung disease. Extracellular vesicles are small, subcellular, membrane-bound vesicles containing cargos from parent cells such as lipids, proteins, genetic information, or entire organelles. These cargos endow extracellular vesicles with biologically active information or functions by which they can reprogram their respective target cells. Recent studies show that extracellular vesicles found in lung-associated biological fluids play key roles as biomarkers and effectors of disease. Conversely, administration of naïve or engineered extracellular vesicles with homeostatic or reparative effects may provide a promising novel protective and regenerative strategy to treat lung disease. To highlight this rapidly developing field, the American Journal of Physiology-Lung Cellular and Molecular Physiology is now launching a special Call for Papers on extracellular vesicles in lung health, disease, and therapy. This review aims to set the stage for this call by introducing extracellular vesicles and their emerging roles in lung physiology and pathobiology.

Transfusion-associated circulatory overload and transfusion-related acute lung injury

Transfusion-associated circulatory overload (TACO) and transfusion-related acute lung injury (TRALI) are syndromes of acute respiratory distress that occur within 6 hours of blood transfusion. TACO and TRALI are the leading causes of transfusion-related fatalities, and specific therapies are unavailable. Diagnostically, it remains very challenging to distinguish TACO and TRALI from underlying causes of lung injury and/or fluid overload as well as from each other. TACO is characterized by pulmonary hydrostatic (cardiogenic) edema, whereas TRALI presents as pulmonary permeability edema (noncardiogenic). The pathophysiology of both syndromes is complex and incompletely understood. A 2-hit model is generally assumed to underlie TACO and TRALI disease pathology, where the first hit represents the clinical condition of the patient and the second hit is conveyed by the transfusion product. In TACO, cardiac or renal impairment and positive fluid balance appear first hits, whereas suboptimal fluid management or other components in the transfused product may enable the second hit. Remarkably, other factors beyond volume play a role in TACO. In TRALI, the first hit can, for example, be represented by inflammation, whereas the second hit is assumed to be caused by antileukocyte antibodies or biological response modifiers (eg, lipids). In this review, we provide an up-to-date overview of TACO and TRALI regarding clinical definitions, diagnostic strategies, pathophysiological mechanisms, and potential therapies. More research is required to better understand TACO and TRALI pathophysiology, and more biomarker studies are warranted. Collectively, this may result in improved diagnostics and development of therapeutic approaches for these life-threatening transfusion reactions.

Large Extracellular Vesicles: Have We Found the Holy Grail of Inflammation?

The terms microparticles (MPs) and microvesicles (MVs) refer to large extracellular vesicles (EVs) generated from a broad spectrum of cells upon its activation or death by apoptosis. The unique surface antigens of MPs/MVs allow for the identification of their cellular origin as well as its functional characterization. Two basic aspects of MP/MV functions in physiology and pathological conditions are widely considered. Firstly, it has become evident that large EVs have strong procoagulant properties. Secondly, experimental and clinical studies have shown that MPs/MVs play a crucial role in the pathophysiology of inflammation-associated disorders. A cardinal feature of these disorders is an enhanced generation of platelets-, endothelial-, and leukocyte-derived EVs. Nevertheless, anti-inflammatory effects of miscellaneous EV types have also been described, which provided important new insights into the large EV-inflammation axis. Advances in understanding the biology of MPs/MVs have led to the preparation of this review article aimed at discussing the association between large EVs and inflammation, depending on their cellular origin.