Fibrinogen and clot-related phenotypes determined by fibrinogen polymorphisms: Independent and IL-6-interactive associations

Atractylodes macrocephala Rhizoma alleviates blood hyperviscosity induced by high-fat, high-sugar, and high-salt diet by inhibiting gut-liver inflammation and fibrinogen synthesis

ETHNOPHARMACOLOGICAL RELEVANCE

Unhealthy dietary patterns and lifestyle changes have been linked to increased blood viscosity, which is recognized as an important pathogenic factor in cardiovascular and cerebrovascular diseases. The underlying mechanism may involve chronic inflammation resulting from intestinal barrier disruption induced by unhealthy diets. The rhizome of Atractylodes macrocephala Koidz. (Called Baizhu in China), is a well-used "spleen-reinforcing" traditional Chinese medicinal herb used for thousands of years. Previous research has demonstrated its multiple gastrointestinal health benefits and its ability to regulate metabolic disorders. However, the effects of Baizhu on blood hyperviscosity induced by long-term unhealthy diets remain unclear.

AIM OF THE STUDY

This study aimed to investigate the effects of the aqueous extract of Baizhu on blood hyperviscosity induced by unhealthy diet and to explore the possible mechanisms.

MATERIALS AND METHODS

The blood hyperviscosity model in SD rats was established utilizing a high-fat, high-sugar, and high-salt diet (HFSSD). Subsequently, the rats underwent a twelve-week intervention with varying doses of Baizhu and a positive control. To evaluate the efficacy of Baizhu on blood hyperviscosity in model rats, we measured behavioral index, hemorheological parameters, inflammatory cytokines, hematology, adhesion molecules, as well as biochemical indicators in serum and liver. We also assessed the pathological states of the colon and liver. Furthermore, Western blotting, ELISA, IHC, and qRT-PCR were used to determine the effect of Baizhu on the IL-6/STAT3/ESRRG signaling pathway and FIB synthesis.

RESULTS

The intervention of Baizhu showed evident attenuating effects on blood viscosity and microcirculation disorders, and exhibit the capacity to moderately modulate parameters including grip, autonomous activities, vertigo time, TC, TG, LDL-c, inflammatory factors, adhesion factors, hematological indicators, etc. At the same time, it reduces liver lipid droplet deposition, restores intestinal integrity, and lowers LPS level in the serum. Subsequent experimental results showed that Baizhu downregulated the expression of TLR4 and NF-κB in colon tissue, as well as the expression of IL-6, TLR4, p-JAK2, p-STAT3, and ESRRG in liver tissue. Finally, we also found that Baizhu could regulate the levels of FIB in plasma and liver.

CONCLUSION

Baizhu protects HFSSD-induced rats from blood hyperviscosity, likely through repairing the intestinal barrier and inhibiting LPS/TLR4-associated liver inflammatory activation, thus suppressing FIB synthesis through the downregulation of IL-6/STAT3/ESRRG pathway.

Mendelian randomization assessing causal relationship between fibrinogen levels and ischemic stroke

OBJECTIVE

High fibrinogen levels are associated with an increased risk of ischaemic stroke (IS). We used mendelian randomisation (MR) to explore a potential causal relationship.

MATERIALS AND METHODS

Data for assessing the relationship between gene variant, disease and biological levels needed for a MR approach was collected using a meta-analytical approach. Inverse-variance weighted (IVW) approach was used for the main analyses and alternative approach for sensitivity analyses. The relationship between fibrinogen levels and IS was assessed using Odds Ratio (OR), while mean difference (g/L) was used for the relationship between SNP (rs1800790) and fibrinogen levels.

RESULTS

The variant FGB rs1800790 SNP was interrogated as an instrumental variable of fibrinogen levels. A meta-analysis with 24 studies (12 case-control and 12 cohort studies, totalling 20,902 cases and 76,510 controls was conducted. Homozygotes (AG) of rs1800790 have 0.14g/L (95%CI: 0.08-0.19, P<0.001) and minor allele (AA) have 0.18g/L (95%CI: 0.01-0.35, P=0.037) higher levels of plasma fibrinogen concentration compared with homozygous for the major allele (GG). The risk of IS was significantly increased in 1-g/L (OR=1.83, 95%CI: 0.92-3.62, P=0.084), or 1-SD of fibrinogen levels (OR=1.39, 95%CI: 1.03-1.87, P=0.030), or above median levels (OR=1.22, 95%CI: 1.02-1.46, P=0.029) or categorical levels tertiles (OR=1.50, 95%CI: 1.26-1.79, P<0.001). Each 1-g/L increase in fibrinogen levels was causally associated with a higher risk of ischemic stroke (OR=2.28, 95%CI: 1.53-3.03, P<0.001) in the Mendelian randomisation analysis.

CONCLUSIONS

Elevated fibrinogen levels are a causative risk factor for ischaemic stroke with each 1g/L increase doubling its risk.

Cardiovascular Disease Risk Factors in the Native American Population

Native Americans are disproportionately affected by cardiovascular disease in comparison with other racial and ethnic groups in the United States. Previous research has analyzed risk factors, quantified prevalence rates, and examined outcomes of cardiovascular disease in Native Americans, yet few studies have considered the role of societal and psychological factors on the increased burden of cardiovascular disease in Native Americans. Modifiable risk factors for cardiovascular disease, including poor nutrition, reduced physical activity, obesity, and increased substance use, are exacerbated in Native American communities due to cultural and historical factors. Further, Native Americans have endured historical trauma and continue to experience additional financial and healthcare stressors, resulting in increased levels of chronic stress. Chronic activation of stress responses through the hypothalamic-pituitary-adrenal and autonomic nervous system increases inflammation and cardiovascular dysfunction resulting in an increased risk for cardiovascular disease. Therefore, it is critical to examine the connection between these stressors and the cardiovascular health disparities in Native American communities to create effective strategies to improve health outcomes.

Unravelling the impact of SARS-CoV-2 on hemostatic and complement systems: a systems immunology perspective

The hemostatic system prevents and stops bleeding, maintaining circulatory integrity after injury. It directly interacts with the complement system, which is key to innate immunity. In coronavirus disease 2019 (COVID-19), dysregulation of the hemostatic and complement systems has been associated with several complications. To understand the essential balance between activation and regulation of these systems, a quantitative systems immunology model can be established. The dynamics of the components are examined under three distinct conditions: the disease state representing symptomatic COVID-19 state, an intervened disease state marked by reduced levels of regulators, and drug interventions including heparin, tranexamic acid, avdoralimab, garadacimab, and tocilizumab. Simulation results highlight key components affected, including thrombin, tissue plasminogen activator, plasmin, fibrin degradation products, interleukin 6 (IL-6), the IL-6 and IL-6R complex, and the terminal complement complex (C5b-9). We explored that the decreased levels of complement factor H and C1-inhibitor significantly elevate these components, whereas tissue factor pathway inhibitor and alpha-2-macroglobulin have more modest effects. Furthermore, our analysis reveals that drug interventions have a restorative impact on these factors. Notably, targeting thrombin and plasmin in the early stages of thrombosis and fibrinolysis can improve the overall system. Additionally, the regulation of C5b-9 could aid in lysing the virus and/or infected cells. In conclusion, this study explains the regulatory mechanisms of the hemostatic and complement systems and illustrates how the biopathway machinery sustains the balance between activation and inhibition. The knowledge that we have acquired could contribute to designing therapies that target the hemostatic and complement systems.

Identification of the FGB gene polymorphism and analysis of its association with fat deposition traits in Hu sheep

As a crucial economic trait, fat deposition is directly related to carcass quality and feed efficiency in sheep. The purpose of this study was to investigate the polymorphisms of the FGB gene related to fat deposition and detect the expression features of the FGB gene in different adipose tissues of sheep by using Sanger sequencing, MassARRAY® SNP technique, and quantitative real-time PCR (qRT-PCR). Results showed that in the intron region of the FGB gene, a SNP g. 3378953 A > T has been identified, and significant association was found between perirenal fat weight, perirenal fat relative weight, mesenteric fat weight, and mesenteric fat relative weight (P < 0.05). Moreover, qRT-PCR analysis showed that FGB was expressed in all three adipose tissues, and FGB gene expression level in the AA genotype was significantly lower than that in the AT or TT genotypes (P < 0.05). Therefore, the FGB gene can be used as a candidate gene to reduce fat deposition in Hu sheep breeding, and the selection of the AA genotype in Hu sheep in production practice is more conducive to improving production efficiency.

HIV infection and ART use are associated with altered plasma clot characteristics in Black South Africans

BACKGROUND

Human immunodeficiency virus (HIV) and antiretroviral treatment (ART) are both associated with hypercoagulability. Altered clot properties could be a potential mechanism thereof. We aimed to investigate the association of HIV and ART, with fibrinogen and plasma clot properties in a group of Black South Africans.

METHODS

At baseline, 151 newly diagnosed people living with HIV (PLWH) and 176 controls were recruited. Some PLWH subsequently commenced with ARTs (n = 70) while others remained ART-naïve (n = 81). Fibrinogen and clot properties (turbidity assay) were investigated from baseline to 5-year follow-up. A sub-group of 21 women (n = 10 ART-treated; n = 11 ART-naïve) with HIV was systematically selected and matched with 12 controls, and additional clot properties (rheometry, permeability and fibre diameter) were investigated.

RESULTS

Fibrinogen was lower in the HIV groups compared to the controls, while % γ' fibrinogen was higher. PLWH had shorter lag times and lower maximum absorbance than the controls (p<0.05). Their CLTs on the other hand were longer. Most variables increased over time in all groups, but differences in the degree of change over time was observed for lag time (p = 0.024) and permeability (p = 0.03). Participants who commenced with ART had a tendency of delayed clot formation (p = 0.08) and increased clot permeability (p = 0.005).

CONCLUSION

PLWH had lower total fibrinogen concentration and formed less dense clots. They also formed clots that were more difficult to lyse, which likely not resulted from altered clot properties. ART use (NNRTI's) had a moderately protective effect, delaying clot formation, and increasing clot permeability.

Comprehensive Analysis of the Role of Fibrinogen and Thrombin in Clot Formation and Structure for Plasma and Purified Fibrinogen

Altered properties of fibrin clots have been associated with bleeding and thrombotic disorders, including hemophilia or trauma and heart attack or stroke. Clotting factors, such as thrombin and tissue factor, or blood plasma proteins, such as fibrinogen, play critical roles in fibrin network polymerization. The concentrations and combinations of these proteins affect the structure and stability of clots, which can lead to downstream complications. The present work includes clots made from plasma and purified fibrinogen and shows how varying fibrinogen and activation factor concentrations affect the fibrin properties under both conditions. We used a combination of scanning electron microscopy, confocal microscopy, and turbidimetry to analyze clot/fiber structure and polymerization. We quantified the structural and polymerization features and found similar trends with increasing/decreasing fibrinogen and thrombin concentrations for both purified fibrinogen and plasma clots. Using our compiled results, we were able to generate multiple linear regressions that predict structural and polymerization features using various fibrinogen and clotting agent concentrations. This study provides an analysis of structural and polymerization features of clots made with purified fibrinogen or plasma at various fibrinogen and clotting agent concentrations. Our results could be utilized to aid in interpreting results, designing future experiments, or developing relevant mathematical models.

Safety of Tigecycline in Patients on Antithrombotic Therapy: A Single-Center Retrospective Study

INTRODUCTION

The aims of the study were to investigate the risk factors of tigecycline-induced hypofibrinogenemia and to evaluate the safety of tigecycline with concomitant antithrombotic drugs.

METHODS

We performed a retrospective analysis of patients who received tigecycline for more than 3 days between January 2015 and June 2019. Clinical and laboratory data were collected including fibrinogen concertation, tigecycline dose, duration of treatment, disease severity, complete blood count, indicators of infection, liver and renal function. Risk factors of hypofibrinogenemia were analyzed by univariate and multivariate analysis. To evaluate the safety of tigecycline and concomitant antithrombotic drugs, bleeding events were assessed by comparing the decline in hemoglobin and the amount of red blood cell transfusion in patients with antithrombotic drugs and those without.

RESULTS

This study included a total of 68 cases, 20 of which experienced hypofibrinogenemia while receiving tigecycline treatment. Duration of treatment, cefoperazone/sulbactam combination therapy, and fibrinogen levels prior to initiation of tigecycline were risk factors associated with tigecycline-induced hypofibrinogenemia. There were 26 recorded bleeding incidents, 25 of which happened before the start of tigecycline. Antithrombotic and non-antithrombotic patients did not differ in their hemoglobin decline or need for red blood cell transfusions while taking tigecycline.

CONCLUSION

A longer treatment duration, cefoperazone/sulbactam combination therapy, and a lower level of fibrinogen before tigecycline were associated with an increased risk of tigecycline-induced hypofibrinogenemia. A combination of antithrombotic drugs and tigecycline did not aggravate the bleeding events during tigecycline treatment.

The hormetic and hermetic role of IL-6

Interleukin-6 is a pleiotropic cytokine regulating different tissues and organs in diverse and sometimes discrepant ways. The dual and sometime hermetic nature of IL-6 action has been highlighted in several contexts and can be explained by the concept of hormesis, in which beneficial or toxic effects can be induced by the same molecule depending on the intensity, persistence, and nature of the stimulation. According with hormesis, a low and/or controlled IL-6 release is associated with anti-inflammatory, antioxidant, and pro-myogenic actions, whereas increased systemic levels of IL-6 can induce pro-inflammatory, pro-oxidant and pro-fibrotic responses. However, many aspects regarding the multifaceted action of IL-6 and the complex nature of its signal transduction remains to be fully elucidated. In this review we collect mechanistic insight into the molecular networks contributing to normal or pathologic changes during advancing age and in chronic diseases. We point out the involvement of IL-6 deregulation in aging-related diseases, dissecting the hormetic action of this key mediator in different tissues, with a special focus on skeletal muscle. Since IL-6 can act as an enhancer of detrimental factor associated with both aging and pathologic conditions, such as chronic inflammation and oxidative stress, this cytokine could represent a "Gerokine", a determinant of the switch from physiologic aging to age-related diseases.

Associations Between 25-Hydroxyvitamin D and Total and γ' Fibrinogen and Plasma Clot Properties and Gene Interactions in a Group of Healthy Black South African Women

The role of 25-hydroxyvitamin D [25(OH)D] in reducing the risk of cardiovascular disease (CVD) has been recognized, but the mechanisms involved are unclear. Researchers have discovered a link between vitamin D and fibrinogen. Until now, data on the relationship between vitamin D and the γ' splice variant of fibrinogen and fibrin clot characteristics remain unexplored. In this study, 25(OH)D, total and γ' fibrinogen, as well as turbidimetrically determined plasma clot properties, were quantified, and fibrinogen and FXIII SNPs were genotyped in 660 Black, apparently healthy South African women. Alarmingly, 16 and 45% of the women presented with deficient and insufficient 25(OH)D, respectively. Total fibrinogen and maximum absorbance (as a measure of clot density) correlated inversely, whereas γ' fibrinogen correlated positively with 25(OH)D. γ' fibrinogen increased whereas maximum absorbance decreased over the deficient, insufficient, and sufficient 25(OH)D categories before and after adjustment for confounders. 25(OH)D modulated the association of the SNPs regarding fibrinogen concentration and clot structure/properties, but did not stand after correction for false discovery rate. Because only weak relationships were detected, the clinical significance of the findings are questionable and remain to be determined. However, we recommend vitamin D fortification and supplementation to reduce the high prevalence of this micronutrient deficiency and possibly to improve fibrinogen and plasma clot structure if the relationships are indeed clinically significant. There is a need for large cohort studies to demonstrate the relationship between vitamin D and cardiovascular and inflammatory risk factors as well as to uncover the molecular mechanisms responsible.

Thrombosis-associated hypofibrinogenemia: novel abnormal fibrinogen variant FGG c.8G>A with oxidative posttranslational modifications

Here, we present the first case of fibrinogen variant FGG c.8G>A. We investigated the behaviour of this mutated fibrinogen in blood coagulation using fibrin polymerization, fibrinolysis, fibrinopeptides release measurement, mass spectrometry (MS), and scanning electron microscopy (SEM). The case was identified by routine coagulation testing of a 34-year-old man diagnosed with thrombosis. Initial genetic analysis revealed a heterozygous mutation in exon 1 of the FGG gene encoding gamma chain signal peptide. Fibrin polymerization by thrombin and reptilase showed the normal formation of the fibrin clot. However, maximal absorbance within polymerization was lower and fibrinolysis had a longer degradation phase than healthy control. SEM revealed a significant difference in clot structure of the patient, and interestingly, MS detected several posttranslational oxidations of fibrinogen. The data suggest that the mutation FGG c.8G>A with the combination of the effect of posttranslational modifications causes a novel case of hypofibrinogenemia associated with thrombosis.

Fibrinogen and Atherosclerotic Cardiovascular Diseases-Review of the Literature and Clinical Studies

Atherosclerotic cardiovascular diseases (ASCVD), including coronary artery disease, cerebrovascular disease, and peripheral arterial disease, represent a significant cause of premature death worldwide. Biomarkers, the evaluation of which would allow the detection of ASCVD at the earliest stage of development, are intensively sought. Moreover, from a clinical point of view, a valuable biomarker should also enable the assessment of the patient’s prognosis. It has been known for many years that the concentration of fibrinogen in plasma increases, inter alia, in patients with ASCVD. On the one hand, an increased plasma fibrinogen concentration may be the cause of the development of atherosclerotic lesions (increased risk of atherothrombosis); on the other hand, it may be a biomarker of ASCVD, as it is an acute phase protein. In addition, a number of genetic polymorphisms and post-translational modifications of fibrinogen were demonstrated that may contribute to the risk of ASCVD. This review summarizes the current data on the importance of fibrinogen as a biomarker of ASCVD, and also presents the relationship between molecular modifications of this protein in the context of ASCVD.

Association of Genetic Polymorphisms of Fibrinogen, Factor XIII A-Subunit and α2-Antiplasmin with Fibrinogen Levels in Pregnant Women

Fibrinogen synthesis is stimulated by proinflammatory triggers and depends on α-, β- and γ-fibrinogen (FGA, FGB, FGG) genotypes. Constellations of fibrinogen, factor XIII A-subunit (F13A) and α₂-antiplasmin (A2AP) genotypes predisposing for dense fibrin gels with high antifibrinolytic capacity (e.g., FGB rs1800790 A-allele carriage in F13A 34Val/Val or A2AP 6Arg/Arg wildtypes) are related with reduced inflammation. As both relationships are likely to influence each other, we tested whether the association of fibrinogen genotypes with fibrinogen levels is influenced by F13A and A2AP genotypes in a population under proinflammatory stress. In total, 639 women were followed during pregnancy (2218 observations). The relationship between fibrinogen genotypes and levels was statistically assessed in univariate and multivariate analyses without and with stratification for F13A Val34Leu and A2AP Arg6Trp. Strong associations with fibrinogen levels could be found for FGB rs1800790G > A, FGA rs2070016T > C and FGG rs1049636T > C. For FGB rs1800790G > A and FGA rs2070016T > C, this relationship significantly depended on F13A Val34Leu and A2AP Arg6Trp genotypes. Specifically, in F13A 34Val/Val wildtypes, carriage of FGB rs1800790A was related to significantly lower fibrinogen levels compared with FGB rs1800790GG wildtypes (p < 0.01). For A2AP 6Arg/Arg wildtypes, a comparable relationship could be found (p < 0.04). As these genotype constellations related to lower fibrinogen levels have previously been shown to be associated with reduced inflammatory activity, these findings suggest that the influence of fibrinogen, F13A and A2AP genotypes on inflammation could affect the control of fibrinogen levels and vice versa.

Certain Associations Between Iron Biomarkers and Total and γ' Fibrinogen and Plasma Clot Properties Are Mediated by Fibrinogen Genotypes

Introduction: Evidence for the relationship between body iron and cardiovascular disease (CVD) is inconsistent and mechanisms involved remain poorly understood. Therefore, we first investigated whether there are linear or non-linear relationships between iron status and total and γ' fibrinogen as well as plasma fibrin clot properties and, second, determined whether there are interactions with iron biomarkers and fibrinogen and FXIII single nucleotide polymorphisms (SNPs) in relation to fibrinogen concentration and functionality. Methods: In this cross-sectional analysis of 2,010 apparently healthy Black South Africans we quantified total and γ' fibrinogen, serum iron, ferritin and transferrin using standardized methods and calculated transferrin saturation (TS). Clot architecture and lysis were explored with a global analytical turbidity assay. The SNPs were determined through an Illumina BeadXpress^® platform. Results: Total, but not %γ', fibrinogen negatively correlated with serum iron concentrations, although both decreased over iron tertiles. %γ' fibrinogen correlated negatively with transferrin and decreased over the transferrin tertiles. A weak negative association between total fibrinogen and TS was detected with fibrinogen decreasing over the TS tertiles and categories based on TS. Lag time correlated positively with transferrin and increased over transferrin tertiles, when adjusting for fibrinogen. Before adjusting for fibrinogen, lag time was shorter in those with adequate iron status based on TS than other iron subcategories. Clot lysis time (CLT) negatively correlated with ferritin and was longer in the first than in the third ferritin tertile. Among iron status categories based on ferritin, only CLT differed and was longer in those with adequate iron than with iron-overload. CLT negatively correlated with TS, albeit weakly, shortened over the TS tertiles and was shorter in those with adequate iron based on TS categories. Interactions were observed between FGB SNPs and some of the markers of iron status investigated, in relation to the clot properties with the most prominent associations detected in homozygous carriers of the variant alleles for whom increased iron status was more beneficial than for those harboring the wild-type alleles. Iron modulated the influence of the SNPs so that for the majority iron was beneficial in respect of clot properties, but even more so for a minority group harboring specific variant alleles. Conclusion: This is the first large-scale epidemiological study to relate fibrinogen concentration and functionality to markers of iron status and to take genetic factors into consideration. We have detected a relationship between iron biomarkers and fibrinogen as well as clot characteristics that are influenced by the genetic make-up of an individual.

Dysfibrinogenemia-Potential Impact of Genotype on Thrombosis or Bleeding

The congenital dysfibrinogenemias, most often associated with bleeding disorders, encompass mutations in the amino-terminal end of fibrinogen α-chain consisting of Gly17-Pro18-Arg19-Val20, known as knob A, which is a critical site for fibrin polymerization. Here we review the studies reporting dysfibrinogenemia due to mutations affecting fibrinogen knob A and identified 29 papers. The number of reports on dysfibrinogenemias related to residues Gly17, Pro18, Arg19, and Val20 is 5, 4, 18, and 2, respectively. Dysfibrinogenemias related to residues Gly17, Pro18, and Val20 are exclusively associated with bleeding tendency. However, the clinical picture associated with dysfibrinogenemia related to residue Arg19 varies, with most patients suffering from bleeding tendencies, but also transitory ischemic attacks and retinal thrombosis may occur. The reason for this variation is unclear. To elaborate the genotype-phenotype associations further, we studied a Danish family with knob A-related dysfibrinogenemia caused by the Aα Arg19Gly (p.Arg19Gly) mutation using whole-exome sequencing and fibrin structure analysis. Our family is the first reported carrying the p.Arg19Gly mutation combined with one or more single nucleotide polymorphisms (SNP)s in FGA, FGB, and/or FGG and increased fibrin fiber thickness and fibrin mass-to-length ratio suffering from pulmonary emboli, suggesting that compound genotypes may contribute to the thrombogenic phenotype of these patients. Our review, accordingly, focuses on significance of SNPs, compound genotypes, and fibrin structure measures affecting the genotype-phenotype associations in fibrinogen knob A mutations.

Fibrin(ogen) as a Therapeutic Target: Opportunities and Challenges

Fibrinogen is one of the key molecular players in haemostasis. Thrombin-mediated release of fibrinopeptides from fibrinogen converts this soluble protein into a network of fibrin fibres that form a building block for blood clots. Thrombin-activated factor XIII further crosslinks the fibrin fibres and incorporates antifibrinolytic proteins into the network, thus stabilising the clot. The conversion of fibrinogen to fibrin also exposes binding sites for fibrinolytic proteins to limit clot formation and avoid unwanted extension of the fibrin fibres. Altered clot structure and/or incorporation of antifibrinolytic proteins into fibrin networks disturbs the delicate equilibrium between clot formation and lysis, resulting in either unstable clots (predisposing to bleeding events) or persistent clots that are resistant to lysis (increasing risk of thrombosis). In this review, we discuss the factors responsible for alterations in fibrin(ogen) that can modulate clot stability, in turn predisposing to abnormal haemostasis. We also explore the mechanistic pathways that may allow the use of fibrinogen as a potential therapeutic target to treat vascular thrombosis or bleeding disorders. Better understanding of fibrinogen function will help to devise future effective and safe therapies to modulate thrombosis and bleeding risk, while maintaining the fine balance between clot formation and lysis.

Lifestyle Influences Changes in Fibrin Clot Properties Over a 10-Year Period on a Population Level

Case-control and observational studies have provided a plausible mechanistic link between clot structure and thrombosis. We aimed to identify lifestyle, demographic, biochemical, and genetic factors that influence changes in total fibrinogen concentration and clot properties over a 10-year period in 2,010 black South Africans. Clot properties were assessed with turbidimetry and included lag time, slope, maximum absorbance, and clot lysis time. Linear mixed models with restricted maximum likelihood were used to determine whether (1) outcome variables changed over the 10-year period; (2) demographic and lifestyle variables, biochemical variables, and fibrinogen single-nucleotide polymorphisms influenced the change in outcome variables over the 10-year period; and (3) there was an interaction between the exposures and time in predicting the outcomes. A procoagulant risk score was furthermore created, and multinomial logistic regression was used to determine the exposures that were associated with the different risk score categories. In this population setting, female gender, obesity, poor glycemic control, increased low-density lipoprotein cholesterol, and decreased high-density lipoprotein cholesterol contributed to the enhanced progression to prothrombotic clot properties with increasing age. Alcohol consumption on the other hand, offered a protective effect. The above evidence suggest that the appropriate lifestyle changes can improve fibrin clot properties on a population level, decreasing cardiovascular disease risk and thus alleviate the strain on the medical health care system.

Biomarkers of Cytokine Release Syndrome Predict Disease Severity and Mortality From COVID-19 in Kidney Transplant Recipients

BACKGROUND

Data on coronavirus disease 2019 (COVID-19) in immunocompromised kidney transplant recipients (KTR) remain scanty. Although markers of inflammation, cardiac injury, and coagulopathy have been previously associated with mortality in the general population of patients with COVID-19, their prognostic impact amongst KTR with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection has not been specifically investigated.

METHODS

We conducted a cohort study of 49 KTR who presented with COVID-19. Clinical and laboratory risk factors for severe disease and mortality were prospectively collected and analyzed with respect to outcomes. The study participants were divided into 3 groups: (1) mild disease manageable in an outpatient setting (n = 8), (2) nonsevere disease requiring hospitalization (n = 21), and (3) severe disease (n = 20).

RESULTS

Gastrointestinal manifestations were common at diagnosis. The 30-day mortality rate in hospitalized patients was 19.5%. Early elevations of C-reactive protein (>100 mg/L) and interleukin-6 (>65 ng/L) followed by increases in high-sensitivity troponin I (>30 ng/L) and D-dimer (>960 ng/mL) were significantly associated with severe disease and mortality. Viral load did not have prognostic significance in our sample, suggesting that outcomes were chiefly driven by a cytokine release syndrome (CRS).

CONCLUSIONS

Regular monitoring of CRS biomarkers in KTR with COVID-19 is paramount to improve clinical outcomes.

Mechanisms of infection by SARS-CoV-2, inflammation and potential links with the microbiome

The pandemic SARS coronavirus 2 utilizes efficient mechanisms to establish infection and evade the immune system. Established infection leads to severe inflammation in susceptible patients, the main hallmark of progression to severe coronavirus disease (COVID-19). Knowledge of the mechanisms of disease has expanded rapidly. As inflammation emerges as the central pathophysiological feature in COVID-19, elucidating how the immune system, lungs and gut communicate and interact with microbial components of the ecological niches that conform the human microbiome will shed light on how inflammation and disease progression are promoted. Studying the microbiome in COVID-19 could allow scientists to identify novel approaches to prevent severe inflammation by targeting components of the human microbiome. Innovation in the aforementioned is needed to combat this pandemic.

The association of alcohol with circulating total fibrinogen and plasma clot density is mediated by fibrinogen and FXIII genotypes

Background

Alcohol consumption is associated with haemostasis and so may influence cardiovascular conditions. It is unknown whether the association of alcohol with total and γ’ fibrinogen concentrations, as well as clot structure, are modulated by fibrinogen and factor (F) XIII single nucleotide polymorphisms (SNPs).

Methods

Total fibrinogen, γ’ fibrinogen and clot properties of 2010 healthy Africans residing in South Africa were measured in relation to alcohol intake as well as its markers – gamma-glutamyltransferase (GGT), percentage carbohydrate deficient transferrin (%CDT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Fourteen fibrinogen and two SNPs in the FXIII gene were genotyped to determine their influence.

Results

Alcohol intake and its markers correlated negatively with fibrinogen and clot lysis time (CLT) as well as with most of the clot properties. Percentage γ’ fibrinogen correlated positively with AST and negatively with alcohol intake. We then stratified for alcohol intake and found inverse associations between γ’ fibrinogen and both %CDT and GGT–CDT in consumers, but the positive association with AST remained only in abstainers. Alcohol intake and its markers modulated the influence of fibrinogen SNPs on total fibrinogen concentrations and the fibrinogen SNPs as well as an FXIII SNP on clot density (all p < 0.004).

Conclusion/s

We show for the first time that some individuals harbour certain genotypes that, in combination with alcohol consumption, might predispose or protect them from haemostatic factors that might lead to the development of cardiovascular disease. Studies are needed to clarify the mechanisms related to the interplay between alcohol and the gene variants observed here.

Oxidative Stress and Inflammation in COVID-19-Associated Sepsis: The Potential Role of Anti-Oxidant Therapy in Avoiding Disease Progression

Since the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak emerged, countless efforts are being made worldwide to understand the molecular mechanisms underlying the coronavirus disease 2019 (COVID-19) in an attempt to identify the specific clinical characteristics of critically ill COVID-19 patients involved in its pathogenesis and provide therapeutic alternatives to minimize COVID-19 severity. Recently, COVID-19 has been closely related to sepsis, which suggests that most deceases in intensive care units (ICU) may be a direct consequence of SARS-CoV-2 infection-induced sepsis. Understanding oxidative stress and the molecular inflammation mechanisms contributing to COVID-19 progression to severe phenotypes such as sepsis is a current clinical need in the effort to improve therapies in SARS-CoV-2 infected patients. This article aims to review the molecular pathogenesis of SARS-CoV-2 and its relationship with oxidative stress and inflammation, which can contribute to sepsis progression. We also provide an overview of potential antioxidant therapies and active clinical trials that might prevent disease progression or reduce its severity.

Relationship between fibrinogen level and its regulatory gene with Alzheimer's disease and vascular dementia

Objective

Methods

Results

Conclusions

Effects of Post-Translational Modifications of Fibrinogen on Clot Formation, Clot Structure, and Fibrinolysis: A Systematic Review

Supplemental Digital Content is available in the text.

Post-translational modifications of fibrinogen influence the occurrence and progression of thrombotic diseases. In this systematic review, we assessed the current literature on post-translational modifications of fibrinogen and their effects on fibrin formation and clot characteristics.

The FDP/FIB Ratio and Blood FDP Level May Be Related to Seizures After Fever in Young Children

Objective: To evaluate the relationship of the blood fibrinogen (FIB) degradation product (FDP) level and FDP/FIB ratio with seizure in young children with fever. Methods: A total of 35 children with simple febrile seizures and 80 children with fever but no seizure were selected. First, the differences in white blood cell (WBC), platelets (PLT), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), FIB, FDP, FDP/FIB ratio, and C-reactive protein (CRP) between 35 children with simple febrile seizures and 40 randomly selected children with fever but no seizure were retrospectively analyzed. Then, an ROC curve was used to determine the diagnostic utility of the FDP level, FDP/FIB ratio, and FDP+FDP/FIB ratio, and the best diagnostic cutoff points were selected. Finally, the diagnostic specificities of the three diagnostic indicators were verified by comparison with the results of all 80 children with fever but no seizure. Results: The FDP level and FDP/FIB ratio were significantly different between the two groups (P < 0.0001) and there was a positive correlation between the FDP and FIB levels. Both the FDP level and FDP/FIB ratio had good diagnostic value. An FDP ≥ 2.0 mg/L and FDP/FIB ratio ≥ 0.5 had good diagnostic specificities. Combined application of an FDP ≥ 2.0 mg/L and FDP/FIB ratio ≥ 0.5 improved the diagnostic power. Conclusions: The blood FDP level and FDP/FIB ratio may be related to seizures after fever, and an FDP ≥ 2.0 mg/L + FDP/FIB ratio ≥ 0.5 has good diagnostic specificity.

Signals from the Niche: Insights into the Role of IGF-1 and IL-6 in Modulating Skeletal Muscle Fibrosis

Muscle regeneration, characterized by the activation and proliferation of satellite cells and other precursors, is accompanied by an inflammatory response and the remodeling of the extracellular matrix (ECM), necessary to remove cellular debris and to mechanically support newly generated myofibers and activated satellite cells. Muscle repair can be considered concluded when the tissue architecture, vascularization, and innervation have been restored. Alterations in these connected mechanisms can impair muscle regeneration, leading to the replacement of functional muscle tissue with a fibrotic scar. In the present review, we will discuss the cellular mediators of fibrosis and how the altered expression and secretion of soluble mediators, such as IL-6 and IGF-1, can modulate regulatory networks involved in the altered regeneration and fibrosis during aging and diseases.