A Hypothesis to Explain the Reported Association of the α-fibrinogen A312 Allele with Thromboembolic Disease

Factor VII R353Q (rs6046), FGA A6534G (rs6050), and FGG C10034T (rs2066865) Gene Polymorphisms and Risk of Recurrent Pregnancy Loss in Iranian Women

Recurrent pregnancy loss is a multi factorial and heterogeneous disorder defined as two or more consecutive pregnancy losses before 20 weeks' gestation. Gene polymorphisms including factor VII R353Q (rs6046), fibrinogen alpha chain A6534G (rs6050) and fibrinogen gamma chain C10034T (rs2066865) have potential role in thrombophilia and the relation between these three polymorphisms and an increased risk of venous thrombosis have been reported. As thrombophilia is associated with a considerable proportion of pregnancy loss and the association between these gene polymorphisms and recurrent pregnancy loss remains controversial, the aim of the present study was to evaluate the relation of these polymorphisms and recurrent pregnancy loss in Iranian women. A total of 144 women with a history of two or more consecutive miscarriages as the patient group and 150 healthy women with two live births and no history of pregnancy loss as the control group were included in the study. Polymerase chain reaction and restriction fragment length polymorphism were used for genotyping. The results were validated by DNA sequencing. The SPSS, SNPStats and Finch TV were used to analyze the results. Factor VII R353Q (rs6046) gene polymorphism showed a significant difference between RPL patients and the control group according to multiple logistic regression models [codominant (OR=0.38; 95% CI=0.23-0.63, P≤0.0001), dominant (OR=0.32; 95% CI=0.20-0.52, P≤0.0001), over dominant (OR=0.46; 95% CI=0.29-0.75, P=0.0017) and log-additive (OR=0.35; 95% CI=0.23-0.53, P≤0.0001)]. Fibrinogen alpha chain A6534G (rs6050) and fibrinogen gamma chain C10034T (rs2066865) gene polymorphisms showed no correlation with recurrent pregnancy loss. Factor VII R353Q (rs6046) gene polymorphism can be considered a risk factor for recurrent pregnancy loss. Further studies in larger populations are needed to confirm the findings.

Molecular Research in Chronic Thromboembolic Pulmonary Hypertension

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) is a debilitating disease, for which the underlying pathophysiological mechanisms have yet to be fully elucidated. Occurrence of a pulmonary embolism (PE) is a major risk factor for the development of CTEPH, with non-resolution of the thrombus being considered the main cause of CTEPH. Polymorphisms in the α-chain of fibrinogen have been linked to resistance to fibrinolysis in CTEPH patients, and could be responsible for development and disease progression. However, it is likely that additional genetic predisposition, as well as genetic and molecular alterations occurring as a consequence of tissue remodeling in the pulmonary arteries following a persistent PE, also play an important role in CTEPH. This review summarises the current knowledge regarding genetic differences between CTEPH patients and controls (with or without pulmonary hypertension). Mutations in BMPR2, differential gene and microRNA expression, and the transcription factor FoxO1 have been suggested to be involved in the processes underlying the development of CTEPH. While these studies provide the first indications regarding important dysregulated pathways in CTEPH (e.g., TGF-β and PI3K signaling), additional in-depth investigations are required to fully understand the complex processes leading to CTEPH.

Fibrinogen heterogeneity: inherited and noninherited

PURPOSE OF REVIEW

Many noninherited or inherited variations have been described in fibrinogen and they may affect the different functions of fibrinogen.

RECENT FINDINGS

A number of the acquired variations in fibrinogen affect the properties of the fibrinogen molecule, such as the conversion rate to fibrin and/or the characteristics of the fibrin clot. Also, genetic polymorphisms are known that can affect the function of the fibrinogen molecule. In addition, some other genetic variants are associated with plasma levels of fibrinogen and with the increase of fibrinogen levels during an acute-phase reaction.

SUMMARY

In this review the authors discuss the noninherited and inherited variations of fibrinogen and the clinical implications (e.g. when determining the risk of cardiovascular disease).

Variable Hypocoagulant Effect of Fish Oil Intake in Humans

Objective— The beneficial effect of dietary fish oil, rich in omega-3 polyunsaturated fatty acids (PUFAs), on cardiovascular disease is multifactorial and may partly rely on their anticoagulant action. We studied how fish oil intake influenced thrombin generation in plasma and which factors were involved herein.

Methods and Results— Twenty-five healthy males with borderline overweight received 3.0 g omega-3 PUFAs daily for 4 weeks. Fish oil intake reduced plasma triglycerides and lowered platelet integrin activation, as well as plasma levels of fibrinogen and factor V, but had no effect on vitamin K-dependent coagulation factors. Before fish oil intake, thrombin generation (reflecting the coagulant potential) considerably varied between plasmas from individual subjects, which were partly explained by variation in prothrombin, antithrombin, fibrinogen, and factor V levels. Fish oil intake reduced thrombin generation in the presence and absence of platelets. This reduction correlated with the fish oil effect on fibrinogen and factor V levels. Interestingly, the lowering effect of fish oil on thrombin generation and fibrinogen clustered around subjects with high fibrinogen carrying a structural fibrinogen α-chain polymorphism.

Conclusions— Dietary omega-3 PUFAs provoke a hypocoagulant, vitamin K-independent effect in humans, the degree of which may depend on fibrinogen level.