Factor XIII B subunit polymorphisms and the risk of coronary artery disease

Genetic landscape in coagulation factor XIII associated defects – Advances in coagulation and beyond

Coagulation factor XIII (FXIII) acts as a fine fulcrum in blood plasma that maintains the balance between bleeding and thrombosis by covalently crosslinking the pre-formed fibrin clot into an insoluble one that is resistant to premature fibrinolysis. In plasma, FXIII circulates as a pro-transglutaminase complex composed of the dimeric catalytic FXIII-A encoded by the F13A1 gene and dimeric carrier/regulatory FXIII-B subunits encoded by the F13B gene. Growing evidence accumulated over decades of exhaustive research shows that not only does FXIII play major roles in both pathological extremes of hemostasis i.e. bleeding and thrombosis, but that it is, in fact, a pleiotropic protein with physiological roles beyond coagulation. However, the current FXIII genetic-epidemiological literature is overwhelmingly derived from the bleeding pathology associated with its deficiency. In this article we review the current clinical, functional, and molecular understanding of this fascinating multifaceted protein, especially putting into the same perspective its genetic landscape.

Angiotensin-Converting Enzyme (ACE) 1 Gene Polymorphism and Phenotypic Expression of COVID-19 Symptoms

The renin–angiotensin–aldosterone system (RAAS) appears to play an important role in SARS-CoV-2 infection. Polymorphisms within the genes that control this enzymatic system are candidates for elucidating the pathogenesis of COVID-19, since COVID-19 is not only a pulmonary disease but also affects many organs and systems throughout the body in multiple ways. Most striking is the fact that ACE2, one of the major components of the RAAS, is a prerequisite for SARS-COV-2 infection. Recently, we and other groups reported an association between a polymorphism of the ACE1 gene (a homolog of ACE2) and the phenotypic expression of COVID-19, particularly in its severity. The ethnic difference in ACE1 insertion (I)/deletion (D) polymorphism seems to explain the apparent difference in mortality between the West and East Asia. The purpose of this review was to further evaluate the evidence linking ACE1 polymorphisms to COVID-19. We searched the Medline database (2019–2021) for reference citations of relevant articles and selected studies on the clinical outcome of COVID-19 related to ACE1 I/D polymorphism. Although the numbers of patients are not large enough yet, most available evidence supports the notion that the DD genotype adversely influences COVID-19 symptoms. Surprisingly, small studies conducted in several countries yielded opposite results, suggesting that the ACE1 II genotype is a risk factor. This contradictory result may be the case in certain geographic areas, especially in subgroups of patients. It may also be due to interactions with other genes or to yet unexplained biochemical mechanisms. According to our hypothesis, such candidates are genes that are functionally involved in the pathophysiology of COVID-19, can act in concert with the ACE1 DD genotype, and that show differences in their frequency between the West and East Asia. For this, we conducted research focusing on Alu-related genes. The current study on the ACE1 genotype will provide potentially new clues to the pathogenesis, treatment, and diagnosis of SARS-CoV-2 infections.

Alu retrotransposons and COVID-19 susceptibility and morbidity

SARS-CoV-2 has spread rapidly across the world and is negatively impacting the global human population. COVID-19 patients display a wide variety of symptoms and clinical outcomes, including those attributed to genetic ancestry. Alu retrotransposons have played an important role in human evolution, and their variants influence host response to viral infection. Intronic Alus regulate gene expression through several mechanisms, including both genetic and epigenetic pathways. With respect to SARS-CoV-2, an intronic Alu within the ACE gene is hypothesized to be associated with COVID-19 susceptibility and morbidity. Here, we review specific Alu polymorphisms that are of particular interest when considering host response to SARS-CoV-2 infection, especially polymorphic Alu insertions in genes associated with immune response and coagulation/fibrinolysis cascade. We posit that additional research focused on Alu-related pathways could yield novel biomarkers capable of predicting clinical outcomes as well as patient-specific treatment strategies for COVID-19 and related infectious diseases.

The factor XIII-A Val34Leu polymorphism decreases whole blood clot mass at high fibrinogen concentrations

BACKGROUND

Factor XIII (FXIII) promotes fibrin crosslinking and red blood cell (RBC) retention in clots. The FXIII-A polymorphism, Val34Leu, is associated with protection against venous thrombosis. This effect is hypothesized to result from fibrinogen concentration-dependent changes in fibrin structure. Effects of the FXIII-A Val34Leu polymorphism in whole blood clots have not been investigated.

AIM

Characterize effects of FXIII-A Val34Leu polymorphism and fibrinogen on whole blood clots.

METHODS

We isolated platelet-poor plasmas from human donors (FXIIIVal/Val , FXIIIVal/Leu , FXIIILeu/Leu ), reconstituted plasmas with platelets and RBCs, and triggered clotting. We assessed contributions of gender, age, clotting times, thrombin generation, FXIII activity, FXIII-A Val34Leu polymorphism, and fibrinogen to clot mass. We also reconstituted FXIII-depleted plasma with platelets, RBCs, and purified FXIIIVal/Val or FXIIILeu/Leu , varied fibrinogen, and characterized effects on clot mass.

RESULTS

Clot mass was associated with age, fibrinogen, prothrombin time, and thrombin generation. Clots reconstituted with plasmas from individuals with FXIII-AVal/Val and FXIII-AVal/Leu did not differ in mass from clots with FXIII-ALeu/Leu . However, clots containing a 34Val allele demonstrated a fibrinogen concentration-dependent increase in mass, whereas clots with homozygous 34Leu did not. In plasmas with high fibrinogen, mass was higher for clots with 34Val alleles compared with clots with homozygous 34Leu. In clots reconstituted with purified FXIII, increasing fibrinogen enhanced clot mass in the presence of 34Val, but decreased mass in the presence of 34Leu.

CONCLUSIONS

FXIII 34Leu mitigates the effect of elevated fibrinogen on whole blood clot mass. The Val34Leu polymorphism may protect against venous thrombosis by reducing clot mass.

Tocilizumab Effects on Coagulation Factor XIII in Patients with Rheumatoid Arthritis

Introduction

Rheumatoid arthritis (RA) is a chronic systemic auto-immune disease associated with a prothrombotic state. Tocilizumab, an interleukin-6 receptor inhibitor, is highly effective in controlling disease activity and thrombotic risk. Factor XIII (FXIII), involved in thrombotic complications, has been reported to be reduced in RA patients during maintenance treatment with tocilizumab, but no data are available before and after the drug administration. Thus, we investigated the effects of tocilizumab on FXIII, thrombin generation and inflammation in patients with RA naïve for the drug.

Methods

We studied 15 consecutive adult patients with RA at baseline and 4 weeks after the onset of parenteral administration of tocilizumab, measuring disease activity and plasma levels of C-reactive protein (CRP), FXIII, and prothrombin fragments F1+2 by immunoenzymatic methods. Fifteen healthy subjects, sex-and age-matched with patients, served as normal controls for laboratory measurements.

Results

At baseline, patients with established RA had a median DAS28 of 4.8 (3.2–8.3) and, compared to healthy controls, had higher plasma levels of CRP (p < 0.0001), FXIII (p = 0.017) and F1+2 (p < 0.0001). Four weeks after starting treatment with tocilizumab, based on the EULAR response criteria, eight patients were classifiable as responders and seven as non-responders. In responders, we observed a statistically significant reduction not only of the values of DAS28 and CRP (p = 0.012 for both), ut also of plasma levels of FXIII (p = 0.05) and F1+2 (p = 0.025). In non-responders, all the studied parameters were unchanged.

Conclusion

The decrease of FXIII and F1+2 levels after tocilizumab treatment observed only in those patients who responded to the drug indicates that the effect of tocilizumab on the prothrombotic state is linked to the control of inflammation and disease activity and not to a direct effect of the drug, thus contributing to the reduction of the cardiovascular risk.

Administration of metformin alleviates atherosclerosis by promoting H2S production via regulating CSE expression

The therapeutic effect of metformin (Met) on atherosclerosis was studied here. Effects of methionine and Met on the induction of inflammatory response and H₂ S expression in peritoneal macrophages were evaluated. Enzyme-linked immunosorbent assay, immunohistochemistry assay, western blot, and quantitative reverse transcription polymerase chain reaction were conducted to observe the levels of cystathionine γ-lyase (CSE), DNA methyltransferases 1 (DNMT1), DNMT3a, DNMT3b, tumor necrosis factor (TNF- α), interleukin 1b (IL-1β), and hydrogen sulfide (H ₂ S). Luciferase and bisulfite sequencing assays were also utilized to evaluate the CSE promoter activity as well as the methylation status of CSE in transfected cells. Methionine significantly elevated Hcy, TNF-a, H ₂ S, and IL-1β expression while decreasing the level of CSE in C57BL/6 mice. In contrary, co-treatment with Methionine and Met reduced the detrimental effect of Methionine. Homocysteine (Hcy) decreased H ₂ S expression while promoting the synthesis of IL-1β and TNF-α in THP-1 and raw264.7 cells. Treatment of THP-1 and raw264.7 cells with methionine and Met reduced the activity of methionine in dose dependently. Moreover, Hcy increased the expression of DNMT and elevated the level of methylation in the CSE promoter, whereas the co-treatment with methionine and Met attenuated the effects of Hcy. Methionine significantly decreased plasma level of CSE while increasing the severity of inflammatory responses and plasma level of Hcy, which in turn suppressed H ₂ S synthesis and enhanced DNA hypermethylation of CSE promoter to promote the pathogenesis of atherosclerosis. In contrary, co-treatment with methionine and Met reduced the detrimental effect of methionine.

Low factor XIII levels after intravenous thrombolysis predict short-term mortality in ischemic stroke patients

In this observational study we investigated whether levels of factor XIII (FXIII) and its major polymorphisms affect the outcome of thrombolysis by recombinant tissue plasminogen activator (rtPA) in acute ischemic stroke (AIS) patients. Study cohort included 132 consecutive AIS patients undergoing i.v. thrombolysis within 4.5 h of symptom onset. Blood samples taken on admission, immediately after and 24 h after therapy were analyzed for FXIII activity and antigen levels. FXIII-A p.Val34Leu, p.Tyr204Phe, FXIII-B p.His95Arg and intron K(IVS11 + 144) polymorphisms were genotyped. Neurological deficit was assessed using the National Institutes of Health Stroke Scale. Intracranial hemorrhage was classified according to ECASSII criteria. Long-term functional outcome was defined at 3 months post-event by the modified Rankin scale. FXIII levels showed a gradual decrease immediately after thrombolysis and 24 h later, which was not related to therapy-associated bleeding. In a multiple logistic regression model, a FXIII level in the lowest quartile 24 h post-lysis proved to be an independent predictor of mortality by 14 days post-event (OR:4.95, 95% CI:1.31-18.68, p < 0.05). No association was found between the investigated FXIII polymorphisms and therapeutic outcomes. In conclusion, our findings indicate that FXIII levels 24 h after thrombolysis might help to identify patients at increased risk for short-term mortality.

Effect of factor XIII levels and polymorphisms on the risk of myocardial infarction in young patients

Factor XIII (FXIII) stabilizes and protects the fibrin network. Its role in myocardial infarction (MI) is still to be clarified. To evaluate the association of FXIII levels with MI in young patients and to investigate how the FXIII-A p.Val34Leu, FXIII-B p.His95Arg, and IVS11, c.1952 + 144 C>G (Intron K) polymorphisms influence FXIII levels and MI risk. Patients with ST elevation MI below 40 years of age (MI, n = 119), age-matched clinical controls (CC, n = 101) without MI and coronary artery disease, and healthy controls (HC, n = 120) were investigated for FXIII activity, FXIII-A₂B₂, FXIII-B concentrations and for the polymorphisms. FXIII activity and FXIII-A₂B₂ antigen were significantly elevated in MI. FXIII activity and antigen were significantly elevated in Arg95, while decreased in Intron K "G" carriers. Smoking had an independent increasing effect on FXIII activity and FXIII-A₂B₂ antigen. Intron K C>G polymorphism significantly decreased the risk of MI in patients with elevated fibrinogen. Among the investigated factors Intron K C>G polymorphism and smoking have the most powerful effect on FXIII levels and on the risk of MI in the young. The effect of smoking on coronary thrombus formation may partially be attributed to its FXIII increasing effect.

Factor XIII levels and factor XIII B subunit polymorphisms in patients with venous thromboembolism

BACKGROUND

The association of plasma factor XIII (FXIII) level with venous thromboembolism (VTE) is still controversial and the effect of sex and FXIII B subunit (FXIII-B) polymorphisms in this respect have not been explored.

OBJECTIVES

1/ To determine FXIII activity and antigen levels in patients with a history of VTE and how they are influenced by sex and FXIII-B polymorphisms. 2/ To explore the association of FXIII levels and FXIII-B polymorphisms with the risk of VTE.

METHODS

218 VTE patients and equal number of age and sex matched controls were enrolled in the study. FXIII activity was measured by ammonia release assay; FXIII-A₂B₂ and FXIII-B levels were determined by ELISAs. FXIII-B polymorphisms were identified by RT-PCR using melting point analysis.

RESULTS

Adjusted FXIII activity and FXIII-A₂B₂ antigen levels were significantly higher in females with a history of VTE than in the respective controls. FXIII-B levels were significantly lower in male VTE patients than in controls. FXIII-A₂B₂ antigen levels in the upper tertile increased the risk of VTE in females (adjusted OR: 2.52; CI: 1.18-5.38). Elevated FXIII-B antigen level had a protective effect only in males (adjusted OR: 0.19; CI: 0.08-0.46). FXIII-B Intron K c.1952+144 C>G polymorphism significantly lowered FXIII activity, FXIII-A₂B₂ and FXIII-B antigen levels in both groups. FXIII-B polymorphisms did not influence the risk of VTE.

CONCLUSIONS

In VTE patients the changes of FXIII level and their effect on the risk of VTE show considerable sex-specific differences. Intron K polymorphism results in decreased FXIII levels, but does not influence the risk of VTE.

Plasma protein profiling in patients undergoing coronary artery bypass grafting surgery and clinical significance

This study was designed to identify the protein profiling in patients with triple vessel coronary artery disease (CAD) undergoing CABG, in order to detect CAD-related differential proteins in these patients. CABG patients with triple vessel disease with/without left main stenosis (n =160) were compared to normal coronary angiographic subjects (n =160). Plasma samples of 20 males and 20 females in each group were analyzed with iTRAQ technique. ELISA test was used to test the chosen proteins from iTRAQ results in plasma samples from a new cohort of the CABG group (n=120, male/femal=61/59) and control (n =120, male/female=60/60). iTRAQ detected 544 proteins with 35 up-regulated and 41 down-regulated (change fold > 1.2 or < 0.83, p < 0.05). Three proteins including platelet factor 4 (PF4), coagulation factor XIII B chain (F13B), and secreted frizzled-related protein 1 (sFRP1) were selected for validation by using ELISA that demonstrated significant up-regulation of PF4 and sFRP1 (p < 0.05). There was a positive correlation between these proteins and CAD (p < 0.05) and myocardial infarction history (p < 0.05). Thus, we for the first time have found 76 proteins differentially expressed in plasma of CABG patients. The thrombotic disease/inflammation progress-related protein PF4 and sFRP1, a member of the Wnt/fz signal-transduction pathway and related to myocardial repair, are significantly up-regulated in triple-vessel disease with/without left main stenosis. PF4 may be developed as a biomarker for the diagnosis of the severity of CAD requiring CABG procedure.

Regulation of plasma factor XIII levels in healthy individuals; a major impact by subunit B intron K c.1952+144 C>G polymorphism

BACKGROUND

The regulation of plasma factor XIII (FXIII) levels in healthy individuals has been only partially explored. The identification of major non-genetic and genetic regulatory factors might provide important information on the contribution of FXIII to the risk of cardio/cerebrovascular diseases.

OBJECTIVES

To determine the effect of age, smoking, BMI, fibrinogen concentration on plasma FXIII activity, complex FXIII antigen (FXIII-A₂B₂) and total FXIII-B subunit (tFXIII-B) level, to correlate FXIII-B level with the other two FXIII parameters and to assess the variation of FXIII levels in carriers of major FXIII subunit polymorphisms.

METHODS

268 healthy individuals were enrolled in the study. FXIII activity was measured by the ammonia release assay; FXIII-A₂B₂ and tFXIII-B were determined by ELISAs. FXIII-A p.Val34Leu, FXIII-B p.His95Arg and FXIII-B intron K c.1952+144 C>G polymorphisms were identified by RT-PCR using melting point analysis with fluorescence resonance energy transfer detection.

RESULTS

All investigated FXIII parameters showed significant positive correlation with age and fibrinogen level; gender and BMI influenced only tFXIII-B. A highly significant positive correlation was demonstrated between tFXIII-B and the other FXIII parameters. FXIII-A p.Val34Leu polymorphism had only slight, if any effect on FXIII levels. The FXIII-B Arg95 allele moderately increased all three FXIII parameters, but the effect became statistically significant only after adjustment. The FXIII-B intron K G allele drastically decreased FXIII levels, and it seemed to be in synergism with the FXIII-A Leu34 allele.

CONCLUSIONS

Plasma FXIII levels are subjected to multifactorial regulation, in which age, fibrinogen level and FXIII-B intron K polymorphism are major determinants.

Blood coagulation factor XIII and factor XIII deficiency

Factor XIII (FXIII) is a multifunctional pro-γ-transglutaminase that, in addition to its well-known role in hemostasis, has a crucial role in angiogenesis, maintenance of pregnancy, wound healing, bone metabolism, and even cardio protection. FXIII deficiency (FXIIID) is a rare bleeding disorder (RBD) with an estimated incidence of one per two million that is accompanied by life-threatening bleeding such as umbilical cord bleeding, recurrent spontaneous miscarriage, and intracranial hemorrhage (ICH). Today, the disease is successfully managed by FXIII concentrate and recombinant FXIII for prophylaxis, management of minor and major bleeding, treatment of ICH, and successful delivery in women with recurrent pregnancy loss. Molecular analysis of patients with FXIIID revealed a wide spectrum of mutations, most frequently missense mutations in the FXIII-A subunit, with a few recurrent mutations observed worldwide. In vitro expression studies revealed that most of the missense mutations cause intracellular instability of the FXIII protein and, subsequently, FXIIID.

Newly-Recognized Roles of Factor XIII in Thrombosis

Arterial and venous thromboses are major contributors to coagulation-associated morbidity and mortality. Greater understanding of mechanisms leading to thrombus formation and stability is expected to lead to improved treatment strategies. Factor XIII (FXIII) is a transglutaminase found in plasma and platelets. During thrombosis, activated FXIII cross-links fibrin and promotes thrombus stability. Recent studies have provided new information about FXIII activity during coagulation and its effects on clot composition and function. These findings reveal newly-recognized roles for FXIII in thrombosis. Herein, we review published literature on FXIII biology and effects on fibrin structure and stability, epidemiologic data associating FXIII with thrombosis, and evidence from animal models indicating FXIII has an essential role in determining thrombus stability, composition, and size.

Factor XIII-A dynamics in acute myocardial infarction: a novel prognostic biomarker?

After acute myocardial infarction (MI) the damaged heart has to be repaired. Factor XIII (FXIII) is considered a key molecule in promoting heart healing. FXIII deficiency was associated to cardiac rupture and anomalous remodelling in MI. During MI, FXIII contributes firstly to the intracoronary thrombus formation and shortly after to heal the myocardial lesion. To quantify the real contribution of FXIII in this process, and to explore its possible prognostic role, we monitored the FXIII-A subunit levels in 350 acute MI patients during the first six days (d0-d5) plus a control at 30-60 days (d30). A one-year follow-up was performed for all the patients. A transient drop in the FXIII-A mean level was noted in the whole cohort of patients (FXIII-Ad0 99.48 ± 30.5 vs FXIII-Ad5 76.51 ± 27.02; p< 0.0001). Interestingly, those who developed post-MI heart failure showed the highest drop (FXIII-Ad5 52.1 ± 25.2) and they already presented with low levels at recruitment. Similarly, those who died showed the same FXIII-A dynamic (FXIII-Ad5 54.0 ± 22.5). Conversely, patients who remained free of major adverse cardiac events, had lower consuming (FXIII-Ad0 103.6 ± 29.1 vs FXIII-Ad5 84.4 ± 24.5; p< 0.0001). Interestingly, the FXIII-A drop was independent from the amount of injury assessed by TnT and CKMB levels. The survival analysis ascribed an increased probability of early death or heart failure inversely related to FXIII-A quartiles (FXIII-A25th< 59.5 %; hazard ratio 4.25; 2.2-5.1; p< 0.0001). Different FXIII-A dynamics and levels could be utilised as early prognostic indicators during acute MI, revealing the individual potential to heal and suggesting tailored treatments to avoid heart failure or its extreme consequence.