Complement in Hemolysis- and Thrombosis- Related Diseases

Adult-onset severe paroxysmal cold hemoglobinuria after COVID-19 successfully treated with sutimlimab

Paroxysmal cold hemoglobinuria (PCH) is a form of cold autoimmune hemolytic anemia characterized by the presence of the Donath-Landsteiner antibody, which triggers complement-mediated intravascular hemolysis when the body temperature changes from cold to warm. PCH occurs primarily in children as a rare, self-limiting disease following viral infections. In contrast, adult-onset PCH is very rare and associated with a diverse range of underlying conditions, which complicates its management and treatment. We describe a case of adult-onset PCH following COVID-19, effectively managed with a single dose of sutimlimab, a selective classical complement pathway inhibitor. This intervention was performed during a life-threatening hemolytic crisis, at a time requiring swift decision-making when specific tests to differentiate from other hemolytic anemias were not readily available. This case illustrates the potential of using a single dose of sutimlimab to manage life-threatening hemolytic crises in PCH, highlighting the significance of inhibiting the classical complement pathway.

Preparation of an anticoagulant polyethersulfone membrane by immobilizing FXa inhibitors with a polydopamine coating

Anticoagulation treatment for patients with high bleeding risk during hemodialysis is challenging. Contact between the dialysis membrane and the blood leads to protein adsorption and activation of the coagulation cascade reaction. Activated coagulation Factor X (FXa) plays a central role in thrombogenesis, but anticoagulant modification of the dialysis membrane is rarely targeted at FXa. In this study, we constructed an anticoagulant membrane using the polydopamine coating method to graft FXa inhibitors (apixaban and rivaroxaban) on the membrane surface. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to characterize the membranes. The apixaban- and rivaroxaban-modified membranes showed lower water contact angles, decreased albumin protein adsorption, and suppressed platelet adhesion and activation compared to the unmodified PES membranes. Moreover, the modified membranes prolonged the blood clotting times in both the intrinsic and extrinsic coagulation pathways and inhibited FXa generation and complement activation, which suggested that the modified membrane enhanced biocompatibility and antithrombotic properties through the inhibition of FXa. Targeting FXa to design antithrombotic HD membranes or other blood contact materials might have great application potential.

Management of Recurrent Venous Thromboembolism in Severe Immune Thrombocytopenia: A Case Report and a Review of the Literature

We report a case of a 58-year-old man with recurrent unprovoked deep vein thrombosis (DVT) and severe immune thrombocytopenia (ITP) with a platelet count of 19 × 109/L. We further review studies reporting venous thromboembolism (VTE) in patients with severe ITP (≤ 35 × 109/L) and identified 14 patients highlighting VTE risk factors and management of these patients. The present case had several risk factors for VTE (previous DVT, obesity, heterozygosity for factor V Leiden mutation, and previous splenectomy). The patient was initially treated with low-molecular-weight heparin followed by long-term apixaban treatment. The literature review together with our case demonstrates that VTE in severe ITP (≤ 35 × 109/L) can occur in patients with VTE risk factors and antithrombotic management of these patients can be achieved without bleeding depending on severity of thrombocytopenia either by full or reduced dose of anticoagulation together with ITP therapy.

Peculiarities of Hemostasis and Proteomics in Patients With Acute Myocardial Infarction and Healthy Volunteers After SARS-CоV-2 Infection

AIM

To identify the features of plasma, platelet hemostasis, and proteomic composition of the blood plasma in patients with acute myocardial infarction (AMI) and healthy volunteers after COVID-19.

MATERIAL AND METHODS

The study included patients with AMI who have recently had COVID-19 (AMI-post-COVID, n=56) and patients with AMI who have not recently had COVID-19 (AMI-control, n=141). Healthy volunteers constituted the control groups and were also divided into control-post-COVID (n=32) and control-control (n=71) groups. Previous SARS-CoV-2 infection was determined by anti-N IgG in the blood serum, the level of which persists for 6-10 months after the disease. Hemostasis was evaluated by thromboelastometry (on whole blood), thrombodynamics (on platelet-poor plasma), fibrinolysis, impedance aggregometry, and proteomic analysis.

RESULTS

The AMI-post-COVID and AMI-control groups had higher values of thrombus growth rate, size and density based on the data of thromboelastometry and thrombodynamics, as well as increased concentrations of the complement system components, proteins regulating the state of the endothelium, and a number of acute-phase and procoagulant proteins compared to the control groups. Furthermore, in the AMI-post-COVID group, compared to the AMI-control group, the thrombus density was lower, and its lysis rates were higher when measured by the thrombodynamics method on platelet-poor plasma, while the platelet aggregation induced by ADP and thrombin was higher. Also, in the control-post-COVID group, compared to the control-control group, the thrombus formation rate was lower, whereas, in contrast, the thrombus size as measured by the thrombodynamics method and the platelet aggregation induced by arachidonic acid and thrombin were higher. In addition, in the AMI-post-COVID group, compared to the AMI-control group, the concentrations of proteins involved in inflammation and hemostasis were lower.

CONCLUSION

Patients with AMI who have recently had COVID-19 are characterized by a less pronounced activation of the immune response compared to patients with AMI who have not had COVID-19. This may be due to long-term chronic inflammation and depletion of components of the immune activation system after SARS-CoV-2 infection. Long-term activation of the hemostasis system in both patients with AMI and healthy volunteers after COVID-19 is primarily due to the platelet component of hemostasis.

Factor XII promotes the thromboinflammatory response in a rat model of venoarterial extracorporeal membrane oxygenation

BACKGROUND

Factor XII (FXII) is a multifunctional protease capable of activating thrombotic and inflammatory pathways. FXII has been linked to thrombosis in extracorporeal membrane oxygenation (ECMO), but the role of FXII in ECMO-induced inflammatory complications has not been studied. We used novel gene-targeted FXII- deficient rats to evaluate the role of FXII in ECMO-induced thromboinflammation.

METHODS

FXII-deficient (FXII-/-) Sprague-Dawley rats were generated using CRISPR/Cas9. A minimally invasive venoarterial (VA) ECMO model was used to compare wild-type (WT) and FXII-/- rats in 2 separate experimental cohorts: rats placed on ECMO without pharmacologic anticoagulation and rats anticoagulated with argatroban. Rats were maintained on ECMO for 1 hour or until circuit failure occurred. Comparisons were made with unchallenged rats and rats that underwent a sham surgical procedure without ECMO.

RESULTS

FXII-/- rats were maintained on ECMO without pharmacologic anticoagulation with low resistance throughout the 1-hour experiment. In contrast, WT rats placed on ECMO without anticoagulation developed thrombotic circuit failure within 10 minutes. Argatroban provided a means to maintain WT and FXII-/- rats on ECMO for the 1-hour time frame without thrombotic complications. Analyses of these rats demonstrated that ECMO resulted in increased neutrophil migration into the liver that was significantly blunted by FXII deficiency. ECMO also resulted in increases in high molecular weight kininogen cleavage and complement activation that were abrogated by genetic deletion of FXII.

CONCLUSIONS

FXII initiates hemostatic system activation and key inflammatory sequelae in ECMO, suggesting that therapies targeting FXII could limit both thromboembolism and inopportune inflammatory complications in this setting.

Ascorbic acid as serine protease inhibitor in lung cancer cell line and human serum albumin

Serine proteases (SPs) are distributed among all living cells accounting for almost one-third of all proteases. Dysregulation of SPs during inflammation and/or infection can result in devastating consequences, such as skin and lung inflammation, neuroinflammation, arthritis, as well as metastasis of cancerous cells. Such activities are tightly regulated by various inhibitors known as serine protease inhibitors (SERPIN). The thermodynamic investigations previously revealed that L-ascorbic acid binds to trypsin more firmly than pepsin and the binding force of L-ascorbic acid is driven by hydrogen bonds and van der Waals forces. However, the physiochemical effects of such interaction on trypsin and/or pepsin have not yet been reported. Ascorbic acid, also known as vitamin C, is one of the essential nutrients and most common food supplements, fortificants, and preservatives. The aim of this study was to explore the inhibitory effects of ascorbic acid on serine proteases at various concentrations on the in-vitro digestion and/or hydrolysis of intercellular matrix of cell monolayer and human serum albumin (HSA). The inhibitory effects of ascorbic on trypsin are investigated by qualitative and quantitative analysis using SDS-PAGE imaging and NIH densitometric software. Upon the addition of ascorbic acid in both indicator systems, the detachment and/or dissociation of cell monolayer and the digestion of HSA were inhibited in the presence of EDTA-Trypsin. The inhibitory effect of ascorbic acid on the digestion of intercellular matrix and/or hydrolysis of HSA showed a dose-dependent trend until it reached the maximum extent of inhibition. At an equal concentration (2.5mg/mL) ascorbic acid and EDTA-Trypsin exhibited the most potent inhibitory effect on the in vitro digestion of protein either in the form of intercellular matrix in cell monolayer and/or HSA respectively. Overall, our results based on two indicator systems strongly indicate that ascorbic acid may function as a serine protease inhibitor (SERPIN) beyond other important functions.

Dissociation Phenomenon of Erythrocyte Agglutination and Its Application to Assay of Functional Activity of the Complement System in Clinical Laboratory

OBJECTIVE

The objective of the study was to validate the dissociation phenomenon of erythrocyte agglutination which is based on erythrocyte fragments and to apply it in the functional activity assay of the complement system.

METHODS

The dissociation-agglutination effect of erythrocyte fragments was validated by detecting the number of free erythrocytes after the action of erythrocyte fragments on agglutinated erythrocytes. The number of free erythrocytes produced after hemolysis of agglutinated erythrocytes caused by complements and complement activators(CAs) was detected by auto hematology analyzer and the results were indicated by mean hemoglobin concentration of erythrocytes (MCHC). We optimized the test conditions and validated the inter-batch stability, explored the resolution of the assay method, and assayed for the total complement activity (AC) and the CAs activated complement activity (ACA) in serum from patients and healthy individual groups.

RESULTS

Erythrocyte fragments have a dissociative effect on agglutinated erythrocytes. The auto hematology analyzer was able to detect AC and ACA, where AC showed an inverse correlation with MCHC, and ACA demonstrated a positive correlation with MCHC. The inter-batch CV of AC, ACA, and ACA/AC was found to be 5%, 9%, and 11.7%, respectively, with good stability. The study found that serum samples from acute phase reaction patients showed significant differences in ACA compared with healthy individuals, with a p value of 0.018; serum samples from patients with nephrotic syndrome showed significant differences in AC, ACA, and ACA/AC compared with healthy individuals, with p values of 0.014, 0.002, and 0.041, respectively.

CONCLUSION

Erythrocyte fragments have dissociation-agglutination effect. The complement system immunological functional detection method, based on this effect, has potential clinical application value due to its sensitivity and accuracy.

Pathophysiology of acute graft-versus-host disease from the perspective of hemodynamics determined by dielectric analysis

BACKGROUND

Numerous reports have demonstrated that the pathophysiology of graft-versus-host disease (GVHD) during hematopoietic stem cell transplantation (HSCT) is closely related to vascular endothelial disorders and coagulation abnormalities. We previously presented the discovery of a principle and the development of a novel instrument for measuring whole blood coagulation. This was achieved by assessing the variations in the dielectric properties of whole blood.

AIM

To investigate how GVHD affects the changes of dielectric properties of whole blood in patients with HSCT.

METHODS

We examined the changes of dielectric properties of whole blood and erythrocyte proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis sequentially in patients with HSCT and compared it with clinical symptoms and inflammatory parameters of GVHD.

RESULTS

During severe GVHD, the dielectric relaxation strength markedly increased and expression of band3 decreased. The dielectric relaxation strength normalized with the improvement of GVHD. In vitro analysis confirmed that the increase of relaxation strength was associated with severe erythrocyte aggregates, but not with decreased expression of band3.

CONCLUSION

Severe erythrocyte aggregates observed in GVHD may cause coagulation abnor malities and circulatory failure, which, together with the irreversible erythrocyte dysfunction we recently reported, could lead to organ failure.

Complement and coagulation crosstalk - Factor H in the spotlight

The immune complement and the coagulation systems are blood-based proteolytic cascades that are activated by pathway-specific triggers, based on protein-protein interactions and enzymatic cleavage reactions. Activation of these systems is finely balanced and controlled through specific regulatory mechanisms. The complement and coagulation systems are generally viewed as distinct, but have common evolutionary origins, and several interactions between these homologous systems have been reported. This complement and coagulation crosstalk can affect activation, amplification and regulatory functions in both systems. In this review, we summarize the literature on coagulation factors contributing to complement alternative pathway activation and regulation and highlight molecular interactions of the complement alternative pathway regulator factor H with several coagulation factors. We propose a mechanism where factor H interactions with coagulation factors may contribute to both complement and coagulation activation and regulation within the haemostatic system and fibrin clot microenvironment and introduce the emerging role of factor H as a modulator of coagulation. Finally, we discuss the potential impact of these protein interactions in diseases associated with factor H dysregulation or deficiency as well as evidence of coagulation dysfunction.

Blood Composite Scores in Patients with Systemic Lupus Erythematosus

Complete blood count-derived ratios have been described as inflammatory biomarkers in several diseases. These hematological scores include the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammatory index ([SIRI]; neutrophils × monocytes/lymphocytes). Our aim was to study how these biomarkers are related to disease expression in a large and well-characterized series of patients with systemic lupus erythematosus (SLE). A total of 284 SLE patients and 181 age- and sex-matched healthy controls were recruited. The NLR, MLR, PLR, and SIRI were calculated, and activity (SLEDAI-2K), severity (Katz), and damage index (SLICC-DI) scores were assessed in patients with SLE. Multivariable linear regression analysis was performed to study whether these scores differ between patients and controls and how they are related to clinical and laboratory features of the disease. Crude cell counts of neutrophils, monocytes, lymphocytes, and platelets were lower in SLE patients compared to controls. Despite this, NLR, MLR, and PRL, but not SIRI, were higher in SLE patients than in controls after multivariable analysis. However, the relationship between the different scores and disease characteristics was limited. Only the Katz severity index revealed a significant positive relationship with SIRI, NLR, and MLR after adjustment for covariates. Similarly, alternative complement cascade activation and low C3 were significantly associated with higher NLR, MLR, and PLR. In conclusion, although cytopenias are a common feature of patients with SLE, hematologic composite scores are independently higher in this population compared to controls. However, the relationship of these scores with the characteristics of the disease is scarce, with the relationship with the complement system being the most consistent.

[Value of complement component 3 in predicting the prognosis of children with sepsis]

OBJECTIVES

To investigate changes in complement component 3 (C3) levels in children with sepsis and its correlation with the severity of sepsis and to explore the significance of C3 in predicting mortality in children with sepsis.

METHODS

A retrospective analysis was conducted on 529 children with sepsis who were admitted to the Pediatric Intensive Care Unit in Hunan Children's Hospital between November 2019 and September 2021. The children were categorized into two groups based on their prognosis at day 28 after sepsis diagnosis: the survival group (n=471) and the death group (n=58). Additionally, the children were divided into normal C3 group (n=273) and reduced C3 group (n=256) based on the median C3 level (0.77 g/L) within 24 hours of admission. Clinical data and laboratory markers were compared between the groups, and assess the predictive value of C3 levels in relation to sepsis-related mortality.

RESULTS

The death group exhibited significantly lower C3 levels compared to the survival group (P<0.05). Multivariate logistic regression analysis revealed that higher pediatric Sequential Organ Failure Assessment (p-SOFA) scores and lower C3 levels were closely associated with sepsis-related mortality (P<0.05). The receiver operating characteristic curve (ROC) analysis demonstrated that combination of p-SOFA scores and C3 levels yielded an area under the ROC curve of 0.852, which was higher than that of each indicator alone (P<0.05).

CONCLUSIONS

C3 can serve as an indicator to assess the severity and prognosis of sepsis in children. The combination of p-SOFA scores and C3 levels holds good predictive value for mortality in children with sepsis.

The choline-binding proteins PspA, PspC, and LytA of Streptococcus pneumoniae and their interaction with human endothelial and red blood cells

Streptococcus pneumoniae is a Gram-positive opportunistic pathogen that can colonize the upper respiratory tract. It is a leading cause of a wide range of infectious diseases, including community-acquired pneumonia and meningitis. Pneumococcal infections cause 1-2 million deaths per year, most of which occur in developing countries. Here, we focused on three choline-binding proteins (CBPs), i.e., PspC, PspA, and LytA. These pneumococcal proteins have different surface-exposed regions but share related choline-binding anchors. These surface-exposed pneumococcal proteins are in direct contact with host cells and have diverse functions. We explored the role of the three CBPs on adhesion and pathogenicity in a human host by performing relevant imaging and functional analyses, such as electron microscopy, confocal laser scanning microscopy, and functional quantitative assays, targeting biofilm formation and the hemolytic capacity of S. pneumoniae. In vitro biofilm formation assays and electron microscopy experiments were used to examine the ability of knockout mutant strains lacking the lytA, pspC, or pspA genes to adhere to surfaces. We found that LytA plays an important role in robust synthesis of the biofilm matrix. PspA and PspC appeared crucial for the hemolytic effects of S. pneumoniae on human red blood cells. Furthermore, all knockout mutants caused less damage to endothelial cells than wild-type bacteria, highlighting the significance of each CPB for the overall pathogenicity of S. pneumoniae. Hence, in addition to their structural function within the cell wall of S. pneumoniae, each of these three surface-exposed CBPs controls or mediates multiple steps during bacterial pathogenesis.

Identifying Aging-Related Biomarkers and Immune Infiltration Features in Diabetic Nephropathy Using Integrative Bioinformatics Approaches and Machine-Learning Strategies

BACKGROUND

Aging plays an essential role in the development of diabetic nephropathy (DN). This study aimed to identify and verify potential aging-related genes associated with DN using bioinformatics analysis.

METHODS

To begin with, we combined the datasets from GEO microarrays (GSE104954 and GSE30528) to find the genes that were differentially expressed (DEGs) across samples from DN and healthy patient populations. By overlapping DEGs, weighted co-expression network analysis (WGCNA), and 1357 aging-related genes (ARGs), differentially expressed ARGs (DEARGs) were discovered. We next performed functional analysis to determine DEARGs' possible roles. Moreover, protein-protein interactions were examined using STRING. The hub DEARGs were identified using the CytoHubba, MCODE, and LASSO algorithms. We next used two validation datasets and Receiver Operating Characteristic (ROC) curves to determine the diagnostic significance of the hub DEARGs. RT-qPCR, meanwhile, was used to confirm the hub DEARGs' expression levels in vitro. In addition, we investigated the relationships between immune cells and hub DEARGs. Next, Gene Set Enrichment Analysis (GSEA) was used to identify each biomarker's biological role. The hub DEARGs' subcellular location and cell subpopulations were both identified and predicted using the HPA and COMPARTMENTS databases, respectively. Finally, drug-protein interactions were predicted and validated using STITCH and AutoDock Vina.

RESULTS

A total of 57 DEARGs were identified, and functional analysis reveals that they play a major role in inflammatory processes and immunomodulation in DN. In particular, aging and the AGE-RAGE signaling pathway in diabetic complications are significantly enriched. Four hub DEARGs (CCR2, VCAM1, CSF1R, and ITGAM) were further screened using the interaction network, CytoHubba, MCODE, and LASSO algorithms. The results above were further supported by validation sets, ROC curves, and RT-qPCR. According to an evaluation of immune infiltration, DN had significantly more resting mast cells and delta gamma T cells but fewer regulatory T cells and active mast cells. Four DEARGs have statistical correlations with them as well. Further investigation revealed that four DEARGs were implicated in immune cell abnormalities and regulated a wide range of immunological and inflammatory responses. Furthermore, the drug-protein interactions included four possible therapeutic medicines that target four DEARGs, and molecular docking could make this association practical.

CONCLUSIONS

This study identified four DEARGs (CCR2, VCAM1, CSF1R, and ITGAM) associated with DN, which might play a key role in the development of DN and could be potential biomarkers in DN.

Red Blood Cells from Individuals with Lesch-Nyhan Syndrome: Multi-Omics Insights into a Novel S162N Mutation Causing Hypoxanthine-Guanine Phosphoribosyltransferase Deficiency

Lesch-Nyhan syndrome (LN) is an is an X-linked recessive inborn error of metabolism that arises from a deficiency of purine salvage enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). The disease manifests severely, causing intellectual deficits and other neural abnormalities, hypercoagulability, uncontrolled self-injury, and gout. While allopurinol is used to alleviate gout, other symptoms are less understood, impeding treatment. Herein, we present a high-throughput multi-omics analysis of red blood cells (RBCs) from three pediatric siblings carrying a novel S162N HPRT1 mutation. RBCs from both parents-the mother, a heterozygous carrier, and the father, a clinically healthy control-were also analyzed. Global metabolite analysis of LN RBCs shows accumulation of glycolytic intermediates upstream of pyruvate kinase, unsaturated fatty acids, and long chain acylcarnitines. Similarly, highly unsaturated phosphatidylcholines are also elevated in LN RBCs, while free choline is decreased. Intracellular iron, zinc, selenium, and potassium are also decreased in LN RBCs. Global proteomics documented changes in RBC membrane proteins, hemoglobin, redox homeostasis proteins, and the enrichment of coagulation proteins. These changes were accompanied by elevation in protein glutamine deamidation and methylation in the LN children and carrier mother. Treatment with allopurinol incompletely reversed the observed phenotypes in the two older siblings currently on this treatment. This unique data set provides novel opportunities for investigations aimed at potential therapies for LN-associated sequelae.

To explore the regulatory effect of Buyang Huanwu Decoction on cerebral infarction based on quantitative proteomics

Buyang Huanwu Decoction (BYHW) contains chemical components such as ligustrazine, oxypaeoniflora, chlorogenic acid, and others. To explore the neuroprotective effect and potential target protein of BYHW in cerebral infarction (CI). A double-blind, randomized controlled trial was established and patients with CI were divided into the BYHW group (n = 35) and the control group (n = 30). To evaluate the efficacy by TCM syndrome score and clinical indicators, and to explore the changes of serum proteins by proteomics technology, so as to explore the mechanism of BYHW and potential target proteins. The study found that compared with the control group, the TCM syndrome score, including Deficiency of Vital Energy (DVE), Blood Stasis (BS), and NIHSS in the BYHW group decreased significantly (p < 0.05), and the Barthel Index (BI) score was significantly higher. A total of 99 differential regulatory proteins were identified by proteomics, which act on lipids and atherosclerosis, complement and coagulation cascade, and TNF-α signaling pathway. In addition, Elisa verified the results of proteomics and found that BYHW can reduce the neurological impairments focus on IL-1β, IL-6, TNF-α, MCP-1, MMP-9, and PAI-1. Significance: In this study, quantitative proteomics was used in combination with liquid chromatography-mass spectrometry (LC-MS/MS) to study the therapeutic effect of BYHW on cerebral infarction (CI) and potential changes in serum proteomics. In addition, the public proteomics database was used for bioinformatics analysis, and Elisa experiment verified the results of proteomics, further clarifying the potential protection mechanism of BYHW on CI.

Targeted Blood Plasma Proteomics and Hemostasis Assessment of Post COVID-19 Patients with Acute Myocardial Infarction

The molecular mechanisms underlying cardiovascular complications after the SARS-CoV-2 infection remain unknown. The goal of our study was to analyze the features of blood coagulation, platelet aggregation, and plasma proteomics in COVID-19 convalescents with AMI. The study included 66 AMI patients and 58 healthy volunteers. The groups were divided according to the anti-N IgG levels (AMI post-COVID (n = 44), AMI control (n = 22), control post-COVID (n = 31), and control (n = 27)). All participants underwent rotational thromboelastometry, thrombodynamics, impedance aggregometry, and blood plasma proteomics analysis. Both AMI groups of patients demonstrated higher values of clot growth rates, thrombus size and density, as well as the elevated levels of components of the complement system, proteins modifying the state of endothelium, acute-phase and procoagulant proteins. In comparison with AMI control, AMI post-COVID patients demonstrated decreased levels of proteins connected to inflammation and hemostasis (lipopolysaccharide-binding protein, C4b-binding protein alpha-chain, plasma protease C1 inhibitor, fibrinogen beta-chain, vitamin K-dependent protein S), and altered correlations between inflammation and fibrinolysis. A new finding is that AMI post-COVID patients opposite the AMI control group, are characterized by a less noticeable growth of acute-phase proteins and hemostatic markers that could be explained by prolonged immune system alteration after COVID-19.

The Complement System in Kidney Transplantation

Kidney transplantation is the therapy of choice for patients who suffer from end-stage renal diseases. Despite improvements in surgical techniques and immunosuppressive treatments, long-term graft survival remains a challenge. A large body of evidence documented that the complement cascade, a part of the innate immune system, plays a crucial role in the deleterious inflammatory reactions that occur during the transplantation process, such as brain or cardiac death of the donor and ischaemia/reperfusion injury. In addition, the complement system also modulates the responses of T cells and B cells to alloantigens, thus playing a crucial role in cellular as well as humoral responses to the allograft, which lead to damage to the transplanted kidney. Since several drugs that are capable of inhibiting complement activation at various stages of the complement cascade are emerging and being developed, we will discuss how these novel therapies could have potential applications in ameliorating outcomes in kidney transplantations by preventing the deleterious effects of ischaemia/reperfusion injury, modulating the adaptive immune response, and treating antibody-mediated rejection.

The Many Faces of Hemolysis

Hemolysis is a problem associated with a variety of red cell pathologies and physiologies not limited to the transfusion of cells. Various pathways lead to the observed outcomes when a hemolytic event occurs. Each event, and the pathway it follows, is based on characteristics of the red cell, the location in which the hemolysis occurs, and the interaction of the immune system. The severity of an event can be predicted with the knowledge of how these 3 factors interface. Although not all hemolytic events are alike, similarities may exist when the pathways overlap.

Pitfalls in complement analysis: A systematic literature review of assessing complement activation

Background

The complement system is an essential component of our innate defense and plays a vital role in the pathogenesis of many diseases. Assessment of complement activation is critical in monitoring both disease progression and response to therapy. Complement analysis requires accurate and standardized sampling and assay procedures, which has proven to be challenging.

Objective

We performed a systematic analysis of the current methods used to assess complement components and reviewed whether the identified studies performed their complement measurements according to the recommended practice regarding pre-analytical sample handling and assay technique. Results are supplemented with own data regarding the assessment of key complement biomarkers to illustrate the importance of accurate sampling and measuring of complement components.

Methods

A literature search using the Pubmed/MEDLINE database was performed focusing on studies measuring the key complement components C3, C5 and/or their split products and/or the soluble variant of the terminal C5b-9 complement complex (sTCC) in human blood samples that were published between February 2017 and February 2022. The identified studies were reviewed whether they had used the correct sample type and techniques for their analyses.

Results

A total of 92 out of 376 studies were selected for full-text analysis. Forty-five studies (49%) were identified as using the correct sample type and techniques for their complement analyses, while 25 studies (27%) did not use the correct sample type or technique. For 22 studies (24%), it was not specified which sample type was used.

Conclusion

A substantial part of the reviewed studies did not use the appropriate sample type for assessing complement activation or did not mention which sample type was used. This deviation from the standardized procedure can lead to misinterpretation of complement biomarker levels and hampers proper comparison of complement measurements between studies. Therefore, this study underlines the necessity of general guidelines for accurate and standardized complement analysis

Lipidomics Revealed Aberrant Lipid Metabolism Caused by Inflammation in Cardiac Tissue in the Early Stage of Systemic Lupus Erythematosus in a Murine Model

Cardiac involvement, displayed as premature cardiovascular disease (CVD), is one of common clinical symptoms of patients with systemic lupus erythematosus (SLE), contributing to mortality of the disease. The precise underlying pathological mechanism(s) for the cardiac involvement in lupus remains poorly understood. Lipids and their metabolites are directly involved in atherosclerosis development, oxidative stress, and inflammation, which are closely related to the development of CVD. In the study, shotgun lipidomics was exploited to quantitatively analyze cellular lipidomes in the cardiac tissue of MRL/lpr mice at two different time points (i.e., pre-lupus and lupus state) with/without treatment with glucocorticoids (GCs). Urine protein, spleen index, and renal histopathological evaluation of the mice were also performed for assessment of SLE onset and/or outcome. Lipidomics analysis revealed that the deposition of cholesterol and the aberrant metabolism of lipids caused by the increased energy metabolism and the enhanced activation of phospholipases, both of which were originally induced by inflammation, were already present in cardiac tissues from lupus-prone mice even at pre-lupus state. These lipid alterations could further induce inflammation and autoimmune responses, accelerating the process of CVD. In addition, the present study also demonstrated that GCs therapy could not only delay the progression of SLE, but also partially corrected these alterations of lipid species in cardiac tissue due to their anti-inflammatory effect. Thus, the medications with better anti-inflammatory effect might be a useful therapeutic method for premature CVD of SLE.

Brief report on the relation between complement C3a and anti dsDNA antibody in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by the production of a diverse array of autoantibodies and the dysfunctional activation of the complement system. The specific association between the complement component C3a (C3a) protein and antibodies specific for double-stranded DNA (anti-dsDNA), however, has not been studied in detail to date. This study was thus designed to more fully explore circulating C3a levels in SLE patients. In total, 13 SLE patients were enrolled in this study after having been diagnosed in accordance with the SLICC classification criteria, with 7 and 6 patients respectively exhibiting positivity for anti-dsDNA and anti-Sm autoantibodies. Serum complement component C1q (C1q) and C3a levels in samples from these patients were detected via Western blotting, while other serological, biochemical, and clinical parkers associated with disease activity were detected using standard laboratory techniques. The levels of serum C3a in anti-dsDNA+ patients were significantly elevated as compared to those in anti-Sm+ patients (P < 0.01), and a positive correlation between serum C3a levels and SLE Disease Activity Index scores was detected (P < 0.05, r = 0.6134). C3a levels are correlated with the degree of SLE disease activity and other clinically relevant readouts in SLE patients. C3a levels may also enable the differentiation between inactive and active SLE, while also offering value as an advantageous biomarker for thrombophilia monitoring in SLE patients.

Alteration of N6-methyladenosine epitranscriptome profile in lipopolysaccharide-induced mouse mesangial cells

N6-Methyladenosine (m6A) is the most prevalent internal modification of messenger RNA (mRNA) in eukaryotes. The underlying molecular mechanisms of m6A modification in chronic glomerulonephritis (CGN) remain unexplored. Here, we performed methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) analyses to assess the alterations of epitranscriptome-wide m6A profile in lipopolysaccharide (LPS)-induced mouse mesangial cells (MMC). The results of our data showed 2153 significantly differential m6A peaks and 358 significantly differentially expressed genes. Furthermore, integrated analysis from MeRIP-seq and RNA-seq identified a total of 64 genes with differential m6A modification and expressed levels, of which 5 genes displayed hypermethylation and upregulation, 42 genes displayed hypermethylation and downregulation, 11 genes displayed hypomethylation and upregulation, and 8 genes displayed hypomethylation and downregulation. Many of them (including Fosl1, Sorbs1, Ambp, Fgfr3, Nedd9, Fgg, Trim13, Fgf22, Mylk, and Muc6) are implicated in the regulation of the immune and inflammatory response. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis found that differential 64 genes were mainly enriched in fatty acid oxidation, apoptosis signaling pathway, complement and coagulation cascades, and PPAR signaling pathway. Together, our study provided a new perspective on the understanding of molecular features of m6A modification in CGN pathogenic pathogenesis.

Efficacy and Mechanism of Buyang Huanwu Decoction in Patients With Ischemic Heart Failure: A Randomized, Double-Blind, Placebo-Controlled Trial Combined With Proteomic Analysis

Objective: Buyang Huanwu Decoction (BYHW), a famous herbal prescription in traditional Chinese medicine (TCM), has been used for 200 years for treating ischemic heart failure (IHF). This study aims to assess the efficacy and safety of BYHW combined with guideline-guided pharmacotherapy in patients with IHF and explore the biological mechanism by which BYHW exerts its efficacy. Methods: In the multicenter, double-blind, randomized controlled trial, a total of 80 patients with IHF were randomized to receive BYHW or placebo for 3 months. The primary efficacy endpoints were New York Heart Association (NYHA) classification, TCM syndrome scores, N-terminal pro-B-type natriuretic peptide (NT-ProBNP), whereas the mechanism exploration endpoints included energy metabolism parameters and coagulation function parameters. In addition, we performed the proteomic study of the serum of patients after treatment by label-free quantification technology to verify the candidate target proteins and pathways. Results: After 3 months of treatment, the NYHA classification, TCM syndrome scores, and the percentage of subjects with at least 30% reduction in NT-ProBNP were significantly improved in the BYHW group, compared with the control group (p < 0.05); BYHW treatment also significantly regulated blood glucose, blood lipid levels, ameliorated energy metabolism and improved coagulation function parameters. There were no significant differences in safety endpoints between the two groups. In addition, we obtained 56 differentially expressed proteins by proteomics, including 20 upregulated proteins and 36 downregulated proteins. Bioinformatic analysis revealed the mechanism of BYHW treatment was significantly related to complement and coagulation cascades, cholesterol metabolism, NF-kappa B signaling pathway, PI3K-Akt signaling pathway, and metabolic pathways. Among these differentially regulated proteins, fibrinogen gamma (FGG), fibrinogen beta (FGB), Carboxypeptidase B2 (CPB2), Coagulation factor XIII A (F13A1), Intercellular adhesion molecule1 (ICAM1), Apolipoprotein C-II(APOC2), Apolipoprotein C-I(APOC1), and CD44 were found to be signature proteins associated with the efficacy of BYHW against IHF. Conclusion: BYHW treatment can further improve cardiac dysfunction and clinical symptoms in IHF based on standard therapy without apparent adverse effects. Additionally, BYHW may play a therapeutic role in IHF by improving energy metabolism and regulating coagulation function through multiple targets and pathways.

Role of Complement System in Kidney Transplantation: Stepping From Animal Models to Clinical Application

Kidney transplantation is a life-saving strategy for patients with end-stage renal diseases. Despite the advances in surgical techniques and immunosuppressive agents, the long-term graft survival remains a challenge. Growing evidence has shown that the complement system, part of the innate immune response, is involved in kidney transplantation. Novel insights highlighted the role of the locally produced and intracellular complement components in the development of inflammation and the alloreactive response in the kidney allograft. In the current review, we provide the updated understanding of the complement system in kidney transplantation. We will discuss the involvement of the different complement components in kidney ischemia-reperfusion injury, delayed graft function, allograft rejection, and chronic allograft injury. We will also introduce the existing and upcoming attempts to improve allograft outcomes in animal models and in the clinical setting by targeting the complement system.

Immune Thrombocytopenic Purpura as a Hemorrhagic Versus Thrombotic Disease: An Updated Insight into Pathophysiological Mechanisms

Immune thrombocytopenic purpura (ITP) is a blood disorder characterized by a low platelet count of (less than 100 × 109/L). ITP is an organ-specific autoimmune disease in which the platelets and their precursors become targets of a dysfunctional immune system. This interaction leads to a decrease in platelet number and, subsequently, to a bleeding disorder that can become clinically significant with hemorrhages in skin, on the mucous membrane, or even intracranial hemorrhagic events. If ITP was initially considered a hemorrhagic disease, more recent studies suggest that ITP has an increased risk of thrombosis. In this review, we provide current insights into the primary ITP physiopathology and their consequences, with special consideration on hemorrhagic and thrombotic events. The autoimmune response in ITP involves both the innate and adaptive immune systems, comprising both humoral and cell-mediated immune responses. Thrombosis in ITP is related to the pathophysiology of the disease (young hyperactive platelets, platelets microparticles, rebalanced hemostasis, complement activation, endothelial activation, antiphospholipid antibodies, and inhibition of natural anticoagulants), ITP treatment, and other comorbidities that altogether contribute to the occurrence of thrombosis. Physicians need to be vigilant in the early diagnosis of thrombotic events and then institute proper treatment (antiaggregant, anticoagulant) along with ITP-targeted therapy. In this review, we provide current insights into the primary ITP physiopathology and their consequences, with special consideration on hemorrhagic and thrombotic events. The accumulated evidence has identified multiple pathophysiological mechanisms with specific genetic predispositions, particularly associated with environmental conditions.

Vaccine-induced COVID-19 mimicry syndrome

To fight the COVID-19 pandemic caused by the RNA virus SARS-CoV-2, a global vaccination campaign is in progress to achieve the immunization of billions of people mainly with adenoviral vector- or mRNA-based vaccines, all of which encode the SARS-CoV-2 Spike protein. In some rare cases, cerebral venous sinus thromboses (CVST) have been reported as a severe side effect occurring 4-14 days after the first vaccination and were often accompanied by thrombocytopenia. Besides CVST, splanchnic vein thromboses (SVT) and other thromboembolic events have been observed. These events only occurred following vaccination with adenoviral vector-based vaccines but not following vaccination with mRNA-based vaccines. Meanwhile, scientists have proposed an immune-based pathomechanism and the condition has been coined vaccine-induced immune thrombotic thrombocytopenia (VITT). Here, we describe an unexpected mechanism that could explain thromboembolic events occurring with DNA-based but not with RNA-based vaccines. We show that DNA-encoded mRNA coding for Spike protein can be spliced in a way that the transmembrane anchor of Spike is lost, so that nearly full-length Spike is secreted from cells. Secreted Spike variants could potentially initiate severe side effects when binding to cells via the ACE2 receptor. Avoiding such splicing events should become part of a rational vaccine design to increase safety of prospective vaccines.

Eculizumab for Refractory Thrombosis in Antiphospholipid Syndrome

Recurrent thrombosis can present in antiphospholipid syndrome despite anticoagulation, antiplatelet, and immunosuppressive therapies.

Complement inhibition may be a therapeutic option for recurrent thrombosis associated with antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is characterized by arterial and/or venous thrombosis with antiphospholipid antibodies. Dysregulation of the complement pathway has been implicated in APS pathophysiology. We report the successful use of eculizumab, an anti-C5 monoclonal antibody, in controlling and preventing recurrent thrombosis in a refractory case of APS. An 18-year-old female was diagnosed with APS after developing extensive, unprovoked deep vein thrombosis (DVT) of axillary, inferior vena cava, and brachiocephalic veins. Thrombophilia evaluation revealed triple-positive lupus anticoagulant, β-2 glycoprotein IgM, IgA, and anticardiolipin antibodies (each >40 U/mL) with persistently positive titers after 12 weeks. She was refractory to multiple anticoagulants alone (enoxaparin, fondaparinux, apixaban, rivaroxaban, and warfarin) with antiplatelet (aspirin and clopidogrel) and adjunctive therapies (hydroxychloroquine, immunosuppression with steroids and rituximab, and plasmapheresis). Despite these, she continued to develop recurrent thrombosis and additionally developed hepatic infarction and pulmonary embolism with failure to decrease titers after 6 weeks of plasma exchange. Following this event, eculizumab (600 mg weekly × 4 weeks followed by 900 mg every 2 weeks) was initiated in combination with fondaparinux, aspirin, clopidogrel, and hydroxychloroquine. She has remained on this regimen without recurrence of thrombosis. Our case suggests that eculizumab may have a role as a therapeutic option in refractory thrombosis in APS.

Severe thrombotic events associated with pre-procedural interruption of anticoagulation in systemic lupus erythematosus with secondary antiphospholipid syndrome: Cases and literature review

BACKGROUND

The American College of Chest Physicians (ACCP) and National Institutes for health and care Excellence in the United Kingdom (NICE) recommend that patients who are high risk for thrombotic events but require cessation of oral anticoagulation with warfarin, due to bleeding risk of a planned procedure, undergo bridging therapy with heparin. However, those conditions which are considered high risk are not universal, nor do guidelines differentiate between low molecular weight heparin (LMWH) and unfractionated heparin. Triple positive antiphospholipid syndrome (APS) is a thrombophilic state with a very high risk for thrombotic events during periods of anticoagulation cessation. Patients with secondary antiphospholipid syndrome in the setting of SLE may be at an even greater risk of thrombotic events during the perioperative period.

PURPOSE

Along with a review of the literature for perioperative management in APS we present three cases of triple positive secondary APS in systemic lupus erythematosus (SLE) patients who had severe thrombotic complications after cessation of their oral anticoagulation despite being bridged with LWMH.

CONCLUSION

Given the severity and rapidity of thrombotic complications with low molecular weight heparin bridging, we propose that all patients with triple positive APS, especially secondary APS with SLE should undergo bridging therapy with intravenous UFH to reduce time without anticoagulation and minimize risk of thrombotic complications. Furthermore, we propose that NICE include APS in the list of medical conditions which are high risk for thrombotic complications and require bridging therapy.

A Flow Cytometry-Based Assay for the Measurement of Total Complement Activity in the Serum and Clinical Practice

Objective

To develop a novel sensitive and accurate assay suitable for high-volume testing of the total complement activity in the serum for clinical laboratories.

Methods

The total complement activity (TCA) to be measured was quantified by detecting the number of fragments produced by erythrocyte lysis and the erythrocyte fragmentation index (EFI), indicating TCA. EFI = M × M2/(M1 + M2), where M is the number of erythrocyte fragments (removed from the background), M1 is the number of unagglutinated red cells, M2 is the number of agglutinated red cell groups, and M2/(M1 + M2) is the agglutination coefficient indicating the degree of erythrocyte agglutination. Mild changes in hemolysin and erythrocyte concentrations were made to optimize the testing conditions. The same serum samples were tested for 10 consecutive days to determine the stability of the experimental results. Serum EFI was detected in both nephrotic syndrome patients and healthy subjects.

Results

There was a linear relationship between hemolysin and erythrocyte agglutination (r = 0.999, P < 0.001). A good linear relationship existed between EFI and TCA (r = 0.991, P < 0.001). The results were not affected by slight fluctuations in the concentrations of hemolysin or erythrocytes. The interbatch CV = 8.6% of the test results showed good stability. There was a significant difference in the EFI between nephrotic syndrome patients and healthy individuals, P < 0.001, and EFI was reduced in nephrotic syndrome patients compared to healthy individuals.

Conclusion

The flow cytometry-based assay for TCA was sensitive and accurate and had potential value for clinical application.

Influence of nanoparticles on the haemostatic balance: between thrombosis and haemorrhage

Maintenance of a delicate haemostatic balance or a balance between clotting and bleeding is critical to human health. Irrespective of administration route, nanoparticles can reach the bloodstream and might interrupt the haemostatic balance by interfering with one or more components of the coagulation, anticoagulation, and fibrinolytic systems, which potentially lead to thrombosis or haemorrhage. However, inadequate understanding of their effects on the haemostatic balance, along with the fact that most studies mainly focus on the functionality of nanoparticles while forgetting or leaving behind their risk to the body's haemostatic balance, is a major concern. Hence, our review aims to provide a comprehensive depiction of nanoparticle-haemostatic balance interactions, which has not yet been covered. The synergistic roles of cells and plasma factors participating in haemostatic balance are presented. Possible interactions and interference of each type of nanoparticle with the haemostatic balance are comprehensively discussed, particularly focusing on the underlying mechanisms. Interactions of nanoparticles with innate immunity potentially linked to haemostasis are mentioned. Various physicochemical characteristics that influence the nanoparticle-haemostatic balance are detailed. Challenges and future directions are also proposed. This insight would be valuable for the establishment of nanoparticles that can either avoid unintended interference with the haemostatic balance or purposely downregulate/upregulate its key components in a controlled manner.

Status of mannose-binding lectin (MBL) and complement system in COVID-19 patients and therapeutic applications of antiviral plant MBLs

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by a virus called "Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)." In the majority of patients, infection with COVID-19 may be asymptomatic or may cause only mild symptoms. However, in some patients, there can also be immunological problems, such as macrophage activation syndrome (CSS) that results in cytokine storm syndrome (CSS) and acute respiratory distress syndrome (ARDS). Comprehension of host-microbe communications is the critical aspect in the advancement of new therapeutics against infectious illnesses. Endogenous animal lectins, a class of proteins, may perceive non-self glycans found on microorganisms. Serum mannose-binding lectin (sMBL), as a part of the innate immune framework, recognizes a wide range of microbial microorganisms and activates complement cascade via an antibody-independent pathway. Although the molecular basis for the intensity of SARS-CoV-2 infection is not generally understood, scientific literature indicates that COVID-19 is correlated with unregulated activation of the complement in terms of disease severity. Disseminated intravascular coagulation (DIC), inflammation, and immune paralysis contribute to unregulated complement activation. Pre-existing genetic defects in MBL and their association with complement play a major role in immune response dysregulation caused by SARS-CoV-2. In order to generate anti-complement-based therapies in Covid-19, an understanding of sMBL in immune response to SARS-CoV-2 and complement is therefore essential. This review highlights the role of endogenous sMBL and complement activation during SARS-CoV-2 infection and their therapeutic management by various agents, mainly plant lectins, since antiviral mannose-binding plant lectins (pMBLs) offer potential applications in the prevention and control of viral infections.

Inflammation, Infection and Venous Thromboembolism

The association between inflammation, infection, and venous thrombosis has long been recognized; yet, only in the last decades have we begun to understand the mechanisms through which the immune and coagulation systems interact and reciprocally regulate one another. These interconnected networks mount an effective response to injury and pathogen invasion, but if unregulated can result in pathological thrombosis and organ damage. Neutrophils, monocytes, and platelets interact with each other and the endothelium in host defense and also play critical roles in the formation of venous thromboembolism. This knowledge has advanced our understanding of both human physiology and pathophysiology, as well as identified mechanisms of anticoagulant resistance and novel therapeutic targets for the prevention and treatment of thrombosis. In this review, we discuss the contributions of inflammation and infection to venous thromboembolism.

C3 glomerulonephritis associated with ANCA positivity: a case report

BACKGROUND

C3 glomerulopathy (C3G) is a recent disease classification that is characterized by the presence of glomerular deposits (composed of C3) in the absence of significant amounts of immunoglobulin and comprises dense deposit disease and C3 glomerulonephritis (C3GN). Most C3GN manifests as membranoproliferative, mesangial proliferative glomerulonephritis patterns via light microscopy. Pure membranous nephropathy (MN)-like glomerular lesions are rare manifestations of C3GN. Anti-neutrophil cytoplasmic antibodies (ANCAs) are also seldomly reported to be positive in C3GN. Herein, we report the case of a C3GN patient presenting with an MN-like glomerular pattern with ANCA positivity.

CASE PRESENTATION

A 68-year-old woman was admitted to a local hospital with elevated serum creatinine for two weeks. Laboratory tests showed a hemoglobin level of 85 g/L. Urinalysis was positive for 2 + protein and 360 RBCs/HPF. Blood biochemistry analysis revealed the following concentrations: albumin, 30.3 g/L; globulin, 46.2 g/L; blood urea nitrogen, 19.9 mmol/L; and serum creatinine, 234 µmol/L. The serum C3 level was 0.4950 g/L, and the serum C4 level was 0.1050 g/L. The direct Coombs test was positive. Serologic testing for ANCA revealed the presence of p-ANCA (1:10) by indirect immunofluorescence microscopy assay, as well as the presence of PR3 1.2 (normal range < 1) and MPO 3.5 (normal range < 1) by enzyme immunoassay. Renal biopsy sample pathology showed 2/6 cellular crescents and thickened glomerular basement membranes. Immunofluorescence testing revealed only diffuse, finely granular depositions of C3 along the glomerular capillary walls in frozen and paraffin-embedded tissue sections. Electron microscopy demonstrated the presence of subepithelial electron-dense deposits, similar to those that are observed in membranous nephropathy. Corticosteroid and cyclophosphamide were administered, with a subsequent improvement in renal function.

CONCLUSIONS

We present the rare case of a patient with MN-like C3GN with ANCA positivity. C3GN with ANCA positivity may be represented by more crescents, severe renal dysfunction and more extrarenal manifestations. More cases are needed to elucidate the clinicopathologic features and optimal treatments of these patients.

COVID-19: imbalance of multiple systems during infection and importance of therapeutic choice and dosing of cardiac and anti-coagulant therapies

The renin-angiotensin-aldosterone system and its metabolites play an important role in homeostasis of body, especially the cardiovascular system. In this study, we discuss the imbalance of multiple systems during the infection and the importance of therapeutic choice, dosing, and laboratory monitoring of cardiac and anti-coagulant therapies in COVID-19 patients. The crosstalk between angiotensin, kinin-kallikrein system, as well as inflammatory and coagulation systems plays an essential role in COVID-19. Cardiac complications and coagulopathies imply the crosstalks between the mentioned systems. We believe that the blockage of bradykinin can be a good option in the management of COVID-19 and CVD in patients and that supportive treatment of respiratory and cardiologic complications is needed in COVID-19 patients. Ninety-one percent of COVID-19 patients who were admitted to hospital with a prolonged aPTT were positive for lupus anticoagulant, which increases the risk of thrombosis and prolonged aPTT. Therefore, the question that is posed at this juncture is whether it is safe to use the prophylactic dose of heparin particularly in those with elevated D-dimer levels. It should be noted that timing is of high importance in anti-coagulant therapy; therefore, we should consider the level of D-dimer, fibrinogen, drug-drug interactions, and risk factors during thromboprophylaxis administration. Fibrinogen is an independent predictor of resistance to heparin and should be considered before thromboprophylaxis. Alteplase and Futhan might be a good choice to assess the condition of heparin resistance. Finally, the treatment option, dosing, and laboratory monitoring of anticoagulant therapy are critical decisions in COVID-19 patients.

Quantitative Acetylomics Revealed Acetylation-Mediated Molecular Pathway Network Changes in Human Nonfunctional Pituitary Neuroendocrine Tumors

Acetylation at lysine residue in a protein mediates multiple cellular biological processes, including tumorigenesis. This study aimed to investigate the acetylated protein profile alterations and acetylation-mediated molecular pathway changes in human nonfunctional pituitary neuroendocrine tumors (NF-PitNETs). The anti-acetyl antibody-based label-free quantitative proteomics was used to analyze the acetylomes between NF-PitNETs (n = 4) and control pituitaries (n = 4). A total of 296 acetylated proteins with 517 acetylation sites was identified, and the majority of which were significantly down-acetylated in NF-PitNETs (p<0.05 or only be quantified in NF-PitNETs/controls). These acetylated proteins widely functioned in cellular biological processes and signaling pathways, including metabolism, translation, cell adhesion, and oxidative stress. The randomly selected acetylated phosphoglycerate kinase 1 (PGK1), which is involved in glycolysis and amino acid biosynthesis, was further confirmed with immunoprecipitation and western blot in NF-PitNETs and control pituitaries. Among these acetylated proteins, 15 lysine residues within 14 proteins were down-acetylated and simultaneously up-ubiquitinated in NF-PitNETs to demonstrate a direct competition relationship between acetylation and ubiquitination. Moreover, the potential effect of protein acetylation alterations on NF-PitNETs invasiveness was investigated. Overlapping analysis between acetylomics data in NF-PitNETs and transcriptomics data in invasive NF-PitNETs identified 26 overlapped molecules. These overlapped molecules were mainly involved in metabolism-associated pathways, which means that acetylation-mediated metabolic reprogramming might be the molecular mechanism to affect NF-PitNET invasiveness. This study provided the first acetylomic profiling and acetylation-mediated molecular pathways in human NF-PitNETs, and offered new clues to elucidate the biological functions of protein acetylation in NF-PitNETs and discover novel biomarkers for early diagnosis and targeted therapy of NF-PitNETs.