Improved Hemoglobin Status and Reduced Menstrual Blood Loss among Female Carriers of Factor V Leiden – An Evolutionary Advantage?

Impact of thrombophilia on venous thromboembolism management

Hypercoagulable states, also called thrombophilia, can either be congenital or acquired. Congenital thrombophilia, associated mainly with venous thrombosis, is either secondary to coagulation-inhibitor deficiencies, i.e., antithrombin, protein C and Protein S, or gain of function mutations, i.e., factor V Leiden and prothrombin G20210A mutations. Despite the relative frequency of these two mutations, they have not been associated with venous thrombosis recurrence. Most prevalent thrombophilia have a limited impact and usually does not change indications for duration of antithrombotic treatment or prophylaxis compared to decisions based on clinical factors. However, rare inherited thrombophilia such as antithrombin deficiency could justify a long-term anticoagulation. The main acquired thrombophilia, the Antiphospholipid syndrome (APS), is associated with both arterial and venous thrombosis. Its impact on patient management is significant: choice of the anticoagulant (DOAC vs. warfarin), duration of anticoagulation, screening of any organ involvement and systemic autoimmune disease, introduction of immunosuppressive therapy.

Exploratory Investigation of the Plasma Proteome Associated with the Endotheliopathy of Trauma

BACKGROUND

The endotheliopathy of trauma (EoT) is associated with increased mortality following injury. Herein, we describe the plasma proteome related to EoT in order to provide insight into the role of the endothelium within the systemic response to trauma.

METHODS

99 subjects requiring the highest level of trauma activation were included in the study. Enzyme-linked immunosorbent assays of endothelial and catecholamine biomarkers were performed on admission plasma samples, as well as untargeted proteome quantification utilizing high-performance liquid chromatography and tandem mass spectrometry.

RESULTS

Plasma endothelial and catecholamine biomarker abundance was elevated in EoT. Patients with EoT (n = 62) had an increased incidence of death within 24 h at 21% compared to 3% for non-EoT (n = 37). Proteomic analysis revealed that 52 out of 290 proteins were differentially expressed between the EoT and non-EoT groups. These proteins are involved in endothelial activation, coagulation, inflammation, and oxidative stress, and include known damage-associated molecular patterns (DAMPs) and intracellular proteins specific to several organs.

CONCLUSIONS

We report a proteomic profile of EoT suggestive of a surge of DAMPs and inflammation driving nonspecific activation of the endothelial, coagulation, and complement systems with subsequent end-organ damage and poor clinical outcome. These findings support the utility of EoT as an index of cellular injury and delineate protein candidates for therapeutic intervention.

Evolution of Factor V Leiden

Factor V Leiden is a procoagulant mutation associated with venous and arterial thrombosis and pregnancy complications. Its high prevalence of 5% in Caucasians suggests that there are evolutionary benefits as well. Carriers are indeed reported to have various advantageous phenotypes related to haemostasis, inflammation and fertility: less acute blood loss; less menstrual blood loss; decreased risk of intracranial haemorrhage; milder phenotypes of haemophilia; higher survival in and lower susceptibility to severe sepsis; higher survival in acute respiratory distress syndrome; less severe diabetic nephropathy and higher fecundity in both men and women. Not all these associations come from high quality adequately powered studies and many have not been confirmed by further research. The evolutionary influence of the alleged associations varies and is difficult to establish, partly due to a shift over time in risk factors of the diseases concerned. For most of the phenotypes possible mechanistic explanations can be provided. The procoagulant phenotype and perhaps also certain pregnancy complications follow from activated protein C (APC) resistance. Elevated APC levels possibly mediate anti-inflammatory effects. Higher sperm counts and more successful embryo implantation seem to play a role in the increased fecundity.

Association between in vitro fertilization outcomes and inherited thrombophilias: a meta-analysis

PURPOSE

The aim of this study was to determine whether in vitro fertilization (IVF) outcomes are associated with inherited thrombophilias.

METHODS

Several databases including PubMed, Embase, and Cochrane Library were retrieved up to 12 January 2016. The quality of the included studies was assessed by two authors. The associations of the following mutations in inherited thrombophilias and IVF outcomes were explored: factor V Leiden (FVL), prothrombin gene G20210A mutation (PGM), 5,10-methylentetrahydrofolate reductase (MTHFR) C677T, MTHFR (A1298C) and activated protein C resistance (APCR). The main outcome measures included CPR and implantation rate (IR). The relative risk (RR) and its 95 % confidence interval (CI) were calculated for effect index. Heterogeneity test was evaluated by Chi-square based on Q statistic and I (2) statistics.

RESULTS

A total of seven articles published between 2007 and 2015 with the ages of subjects between 30.9 and 36.2 were included. For subgroups analysis of CPR or IR, there were no significant differences in MTHFR (C377T), MTHFR (A1298C), FVL, PGM, and FVL/PGM mutation were found between the mutation group and control group (P > 0. 05).

CONCLUSIONS

IVF outcomes are not associated with FVL, PGM, MTHFR (C677T), MTHFR (A1298C), and APCR mutation in inherited thrombophilias.

Why is factor V Leiden so rare in the Basques?

Factor V Leiden is the most common inherited trait in Caucasians that predisposes individuals to venous thrombosis. However, it is almost absent amongst the Basque people that live in the south western part of Europe. To explain this finding, we speculate upon the putative contribution of various evolutionary forces through which the Basque genome may have been shaped.

Activated protein C resistance testing for factor V Leiden

Activated protein C resistance assays can detect factor V Leiden with high accuracy, depending on the method used. Factor Xa inhibitors such as rivaroxaban and direct thrombin inhibitors including dabigatran, argatroban, and bivalirudin can cause falsely normal results. Lupus anticoagulants can cause incorrect results in most current assays. Assays that include dilution into factor V-deficient plasma are needed to avoid interference from factor deficiencies or elevations, which can arise from a wide variety of conditions such as warfarin, liver dysfunction, or pregnancy. The pros and cons of the currently available assays are discussed.

Caution in interpreting results from imputation analysis when linkage disequilibrium extends over a large distance: a case study on venous thrombosis

By applying an imputation strategy based on the 1000 Genomes project to two genome-wide association studies (GWAS), we detected a susceptibility locus for venous thrombosis on chromosome 11p11.2 that was missed by previous GWAS analyses that had been conducted on the same datasets. A comprehensive linkage disequilibrium and haplotype analysis of the whole locus where twelve SNPs exhibited association p-values lower than 2.23 10(-11) and the use of independent case-control samples demonstrated that the culprit variant was a rare variant located ~1 Mb away from the original hits, not tagged by current genome-wide genotyping arrays and even not well imputed in the original GWAS samples. This variant was in fact the rs1799963, also known as the FII G20210A prothrombin mutation. This work may be of major interest not only for its scientific impact but also for its methodological findings.

Factor V Leiden thrombophilia

Factor V Leiden is a genetic disorder characterized by a poor anticoagulant response to activated Protein C and an increased risk for venous thromboembolism. Deep venous thrombosis and pulmonary embolism are the most common manifestations, but thrombosis in unusual locations also occurs. The current evidence suggests that the mutation has at most a modest effect on recurrence risk after initial treatment of a first venous thromboembolism. Factor V Leiden is also associated with a 2- to 3-fold increased relative risk for pregnancy loss and possibly other obstetric complications, although the probability of a successful pregnancy outcome is high. The clinical expression of Factor V Leiden is influenced by the number of Factor V Leiden alleles, coexisting genetic and acquired thrombophilic disorders, and circumstantial risk factors. Diagnosis requires the activated Protein C resistance assay (a coagulation screening test) or DNA analysis of the F5 gene, which encodes the Factor V protein. The first acute thrombosis is treated according to standard guidelines. Decisions regarding the optimal duration of anticoagulation are based on an individualized assessment of the risks for venous thromboembolism recurrence and anticoagulant-related bleeding. In the absence of a history of thrombosis, long-term anticoagulation is not routinely recommended for asymptomatic Factor V Leiden heterozygotes, although prophylactic anticoagulation may be considered in high-risk clinical settings. In the absence of evidence that early diagnosis reduces morbidity or mortality, decisions regarding testing at-risk family members should be made on an individual basis.

Detection of Factor V Leiden and prothrombin c.20210G>A allele by Roche Diagnostics LightCycler®

Venous thrombosis affects one in one thousand people each year, and in many countries, it is a major cause of morbidity and death in hospitalised patients. Factor V Leiden and the prothrombin c.20210G>A transition are relatively common in the Western World, and both increase the risk of venous thrombosis. The author describes the detection of t+++hese two genetic variants on the carousel-based Roche LightCycler®. This simple method has high sensitivity for DNA, making it possible to test blood samples without the need for traditional DNA extraction and purification.

Increased sperm count may account for high population frequency of factor V Leiden

BACKGROUND

Factor V Leiden (FVL) increases the risk of venous thrombosis and pregnancy loss in carriers. Nevertheless, this relatively old mutation is prevalent in Caucasion populations, which could be explained by positive selection pressure. Men with FVL have previously been found to have higher fecundity (the time between marriage and first pregnancy). Whether this is caused by increased sperm counts in men with FVL is unknown.

OBJECTIVES

To assess whether men with factor V Leiden have increased sperm counts.

PATIENTS/METHODS

We performed a prospective cohort study among 1139 consecutively included male partners of subfertile couples presenting at our university hospital for fertility workup between January 2000 and July 2007. All potential candidates who gave informed consent were included, irrespective of their fertility workup. In this retrospective analysis, we excluded participants with known causes of spermatogenic function or azoospermia. Subsequently, we genotyped all participants and compared sperm counts between FVL carriers and non-carriers.

RESULTS

We identified 37 FVL carriers and 921 non-carriers. FVL carriers had higher total sperm counts and total motile sperm counts than non-carriers: 236 x 10(6) (95% CI 158-292 x 10(6)) vs. 163 x 10(6) (95% CI 147-178 x 10(6)) and 81 x 10(6) (95% CI 54-105 x 10(6)) vs. 52 x 10(6) (95% CI 48-57 x 10(6)), respectively.

CONCLUSIONS

To our knowledge, this is the first study that indicates that an increased incidence of a genotype may be controlled by increased sperm counts. However, the finding that men with FVL had higher total (motile) sperm counts was not statistically significant and needs confirmation in other studies.

Is factor V Leiden mutation a cause of in vitro fertilization failure?

This prospective cohort study tested whether the most common hereditary thrombophilia, factor V Leiden (FVL) mutation, is associated with nonpregnancy after IVF. Factor V Leiden mutation prevalence was very low (1.6%) and had a preliminarily positive association with pregnancy, suggesting that routine testing in a general IVF population for FVL mutation as a cause of IVF failure and infertility is not indicated.

The hemostatic balance revisited through the lessons of mankind evolution

Under physiologic conditions, a hemostatic balance is achieved through the effects of natural procoagulant and anticoagulant factors which, in equilibrium with each other, provide hemostasis at the sites of vascular injury. Abnormalities of these hemostasis factors can result in a tendency toward hemorrhagic or thrombotic events. In this review the influence of inherited prothrombotic risk factors--especially the more frequent factor V Leiden and prothrombin gene mutations--on normal and abnormal hemostasis is analyzed from an evolutionary point of view. The effect of inherited bleeding disorders on the development of thrombotic or atherosclerotic processes is also discussed.

Protein Z/Z-dependent protease inhibitor (PZ/ZPI) anticoagulant system and thrombosis

A new anticoagulant system involving a serpin has been recently characterised. The protein Z/Z-dependent protease inhibitor (PZ/ZPI) system inhibits activated factors X, XI and IX by different mechanisms. By homology with other anticoagulant systems (antithrombin or the protein C/protein S), deficiency of the serpin (ZPI) or its cofactor (PZ) might imbalance the haemostatic system with thrombotic consequences. Evidence supports the in vivo anticoagulant role of this complex and the thrombotic consequences of its deficiency. Non-sense variations of the ZPI (W303X and R67X) have been associated with increased risk of venous thrombosis. Moreover, PZ deficient mice carrying the FV Leiden have a thrombotic phenotype. Finally, some reports suggest that PZ deficiency might increase the risk of thrombosis. However, other studies question the thrombotic relevance of both ZPI and PZ deficiencies. This system could play a redundant role in haemostasis that explains the conflicting results on its thrombotic potential, which might be exacerbated in combination with other prothrombotic factors.

Prothrombin 20210G>A is an ancestral prothrombotic mutation that occurred in whites approximately 24 000 years ago

Prothrombin 20210G>A and factor V Leiden are common prothrombotic mutations in whites for which founder effects have been established. In this study, we analyzed the frequencies of 5 single nucleotide polymorphisms (SNPs) and 9 microsatellites flanking the prothrombin gene (F2) in 88 homozygotes for 20210A and 66 homozygotes for 20210G. For estimating the age of the prothrombin 20210G>A mutation, we used the DMLE+2.0 program, which analyzed linkage disequilibria between the mutation and the multiple markers that had been assessed. This analysis yielded an age estimate of 23 720 years (95% credible set, 19 080-31 340 years). A similar analysis by the DMLE+2.0 program was performed on 5 SNPs from previously studied homozygotes for factor V Leiden and controls that yielded an age estimate of 21 340 years (95% credible set, 16 880-29 480 years). The occurrence of the 2 mutations in whites toward the end of the last glaciation and their presently wide distribution in whites suggest selective evolutionary advantages for which some evidence was reported (diminished blood loss) or is controversial (protection against infections).

Factor V Leiden as a Common Genetic Risk Factor for Venous Thromboembolism

PURPOSE

To increase nurses' knowledge of the Factor V Leiden (FVL) genetic trait for venous thromboembolism.

ORGANIZING FRAMEWORK

An overview of the history, prevalence, and predisposition of the FVL genetic mutation, including who should be tested and how and in what circumstances people with FVL should be treated.

FINDINGS

FVL is the most commonly recognized genetic trait associated with venous thrombosis. It is found predominantly in Caucasian populations. Biochemically it causes "activated protein C resistance (APCR)." The decision to test for FVL depends on whether the information gained will potentially improve the health care of the person or family. For people who have had deep venous thrombosis, testing for FVL will likely not alter treatment approaches. Currently the advantage for testing is primarily limited to asymptomatic family members who carry FVL and who have had deep vein thrombosis. Close relatives who also carry the mutated gene might benefit from prophylactic anticoagulation when their risk of thrombosis is increased by temporary factors such as surgery.

CONCLUSIONS

Nurses are in a unique position to provide accurate information and counseling when patients and their family members are presented with the results of thrombophilia testing.

Pharmacogenetics in ovarian stimulation - current concepts and future options

Tailoring ovarian stimulation to the individual patient can be challenging because the ovarian response varies substantially between patients. Pharmacogenetics has emerged as a new area of research to improve the balance between desired and undesired actions of drugs, based upon the genetic predisposition of the individual patient. Clinical studies have demonstrated that the p.N680S polymorphism of the FSH-receptor gene determines the ovarian response to FSH stimulation in patients undergoing IVF. In homozygous Ser(680)/Ser(680) type women, the FSH receptor appears to be more resistant to FSH action even in normal menstrual cycles. Therefore, genotyping of patients scheduled for ovarian stimulation could be an attractive tool to individualize FSH dosing according to genetic differences in ovarian sensitivity. More clinical studies are warranted to investigate the usefulness of genotyping for the p.N680S polymorphism as a routine diagnostic test before ovarian stimulation.

Activated protein C resistance -- in the absence of factor V Leiden -- and pregnancy

BACKGROUND

Activated protein C (APC) resistance with or without factor V Leiden (FVL) is a major risk factor for venous thromboembolism. Many previous pregnancy studies have been focused on APC resistance caused by FVL. Very few have investigated APC resistance in the absence of FVL (APCR(FVL-)).

MATERIAL AND METHODS

In a prospective study of 2480 unselected gravidae, blood was drawn in early pregnancy (mean = 12 weeks of gestation). APC resistance was analyzed by an APTT-based method (Coatest) APC-resistance) and the presence of FVL was determined by PCR. The APCR(FVL-) group had similar mean APC resistance ratio as the heterozygous carriers of FVL. The analyses were carried out no earlier than 3 months after delivery when all data were recorded. Small-for-gestational age (SGA) was used as a proxy for intrauterine growth restriction.

RESULTS

When compared with the control group, women with APCR(FVL-) had no increased risk of SGA, pre-eclampsia, first trimester fetal loss or venous thromboembolism. However, they had an increased risk of second trimester fetal loss (7.3% vs. 2.7%, P = 0.01), and a tendency of being overweight (17.3% vs. 12.6%, P = 0.19) and of delivering extremely preterm (2.8% vs. 1.0%, P = 0.11).

CONCLUSION

Women with APC resistance not caused by FVL were not at increased risk for SGA, pre-eclampsia, first trimester fetal loss, or abnormal blood loss. However, they showed an increased prevalence of second trimester fetal loss.

Gender-specific association of the factor V Leiden mutation with fertility and fecundity in a historic cohort. The Leiden 85-Plus Study

BACKGROUND

Factor V Leiden (FVL, Arg506Gln) mutation may facilitate embryo implantation and increase fertility and fecundity. This was studied in subjects who were of childbearing age in a time with minimal fertility control without modern contraceptive methods.

METHODS

From 1986 to 1999, 1502 inhabitants of Leiden, The Netherlands, reaching the age of 85 years were enrolled in the Leiden 85-Plus Study. Of 1176 subjects the FVL status was analysed, in 365 male and 811 female subjects.

RESULTS

The FVL carrier rate was 4.3%. Fertility was not affected by FVL status. In male subjects, fecundity (interval between marriage and birth of first child) was significantly increased in FVL carriers; 67% of male FVL carriers had a child within 371 days of marriage (therefore conceived within 3 months of marriage), compared with 19% of male non-carriers [relative risk (RR), 3.5; 95% confidence interval (CI), 2.1-5.7; P < 0.001]. Within 6 months of marriage, 75% of male FVL carriers had conceived a child compared with 34% male non-carriers (RR, 2.2; 95% CI, 1.5-3.2; P = 0.01). In female subjects, fecundity was not influenced by FVL status.

CONCLUSION

Fecundity is increased in male FVL carriers; in female subjects, no such association was observed.

Inherited defects of coagulation Factor V: the thrombotic side

DNA variations in the Factor V gene have played a major role in thrombosis research ever since the discovery of Factor V Leiden. Here, all relatively common DNA variations in the coding regions of the Factor V gene are discussed. Many of them have been associated with venous thrombosis or related diseases. However, most variations have been studied separately, without taking the presence of other variations in the same gene into account. This means that their association with disease should be interpreted with caution, as it may reflect linkage with another variation. An approach in which a haplotype-based analysis of the Factor V gene is combined with in vitro assays of recombinant proteins is advocated. Finally, a possible reason for the relatively polymorphic nature of the Factor V protein is discussed.

Factor V Leiden mutation in relation to fecundity and miscarriage in women with venous thrombosis

BACKGROUND

Factor V Leiden mutation (Arg506Gln) increases the likelihood of venous thrombosis; it may also have a positive effect through facilitation of embryo implantation. This may manifest itself as a reduced time to pregnancy (increased fecundity) and fewer miscarriages in the first trimester.

METHODS

From March 1999 onwards, consecutive patients with a first venous thrombosis (VT) were recruited. The first 115 female VT patients with factor V Leiden and 230 age-matched female VT patients without factor V Leiden were included. All patients, unaware of their genotype, received a structured questionnaire.

RESULTS

Of the 297 (86%) women who returned the questionnaire, 220 had been pregnant at least once. Time to first pregnancy was unaffected by carrier status: 58% factor V Leiden carriers reported a pregnancy within 3 months compared to 54% non-carriers. The miscarriage proportion was 14%, similar in both groups. First trimester miscarriage was less frequent among carriers (46%) than among non-carriers (95%) (relative risk 0.5, 95% confidence interval 0.3-0.9).

CONCLUSIONS

Factor V Leiden mutation may support embryo implantation, as factor V Leiden carriers had fewer miscarriages in the first trimester with a similar overall miscarriage rate. Miscarriage of embryos with poor viability may be postponed until the second trimester in factor V Leiden carriers. Fecundity was not influenced by factor V Leiden status.

The discovery of activated protein C resistance

Venous thrombosis is a multifactorial disease, with the pathogenesis involving genetic and environmental risk factors. The most common genetic risk factor known to date is a single point mutation in the gene of coagulation factor V (FV), which results in the replacement of Arg506 with Gln (FV Leiden). Arg506 is one of several cleavage sites in FV for anticoagulant activated protein C (APC) and the mutation results in the loss of the cleavage site. Via a complicated series of reactions, this results in impaired APC-mediated degradation of both FVa and FVIIIa. The associated hypercoagulable condition, which causes a lifelong increased risk of thrombosis, is known as APC resistance. APC resistance was discovered in my laboratory in the late 1980s and we published the first report almost exactly 10 years ago. This started an avalanche of research activities and several thousand articles have since been published on this topic. Analyses for APC resistance and FV Leiden have made their way into clinical medicine and are now performed routinely all over the world. I have been asked to write a personal historical annotation about the discovery of APC resistance, the early research activities and the rapid progress in this field.