Low endogenous thrombin potential in trained subjects

Evaluation of hemostatic capacities among commando candidates: Would their blood suit a hemorrhagic war-injured patient in case of blood donation on the battlefield?

BACKGROUND

In case of a warm fresh whole blood transfusion on the battlefield, the blood donation usually occurs just after a combat phase and often after several days on the fields. To explore the hemostatic capacity of such blood, we analyzed the blood of volunteers attending the commando course of the French Navy, considering this course as an experimental model, placing them into the same physiological conditions as those faced by deployed fighters.

METHODS

Venous blood was collected at the beginning of the course, mimicking their baseline status, and a second time 6 weeks later, from the remaining candidates, during the actual commando training, mimicking the stress conditions. For each candidate, we observed the differences between the two blood samples.

RESULTS

Of the 112 men that attended the first day of the course, only 17 remained 6 weeks later. In the second blood samples, we noted significant increased leucocytes and platelets counts and significant decreased hematocrit and hemoglobin levels. Thrombin generation assays showed significantly lower normalized peak heights (-31%), lower normalized endogenous thrombin potential values (-29%), and lower velocity index (-35%). Normalized lag time and time to peak did not differ. Viscoelastometric testing revealed a significant increasing in clot firmness as assessed by maximum amplitude and amplitude at 6 minutes. The clot speed was significantly increased.

CONCLUSION

This work brings new data on coagulation during prolonged and considerable physical exercise. No obvious deleterious modification of hemostatic properties was observed. The decrease of the endogenous thrombin potentials may reflect a better ability to control the thrombin generation once started. Altogether, these results suggest that this blood could suit well a hemorrhagic war-injured patient.

LEVEL OF EVIDENCE

Prospective observational cohort study, Level III.

Exercise and Circulating Microparticles in Healthy Subjects

This study aimed to explore the relationship between exercise and circulating microparticles (CMPs). PubMed, Web of Science, Embase, and the Cochrane Library databases were searched until August 13, 2020, using the terms "exercise" and "cell-derived microparticles." The Cochrane tool of risk of bias and the Methodological Index for Non-Randomized Studies were used to grade the studies. Twenty-six studies that met criteria were included in this review, including one before-after self-control study, 2 cohort studies, 4 randomized control trials, 5 case-control studies, and 14 descriptive studies. The studies were divided into a single bout and long-term exercise. The types of MPs contained endothelium-derived microparticles (EMPs), leukocyte-derived microparticles (LMPs), platelet-derived microparticles (PMPs), and erythrocyte-derived microparticles (ErMPs). This first systematic review found that the levels of CMPs continued to increase after a single bout of exercise in untrained subjects and were lower in trained subjects. PMPs expressed a transient increase after a single bout of exercise, and the proportion and duration of PMPs increment reduced in long-term exercise. Most studies showed a decline in LMPs in trained subjects after a single bout and long-term exercise, and variable changes were found in EMPs and ErMPs after exercise. A single bout of exercise drives the vessels exposed to high shear stress that promotes the formation of CMPs. However, the decline in CMPs in trained subjects may be attributed to the fact that they have a better ability to adapt to changes in hemodynamics and cellular function during exercise.

Effects of 6 Months of Active Commuting and Leisure-Time Exercise on Fibrin Turnover in Sedentary Individuals with Overweight and Obesity: A Randomised Controlled Trial

Obesity and exercise constitute important factors for cardiovascular disease risk, but the long-term effects of different exercise modalities on haemostatic biomarkers are not well elucidated. We investigated the effects of 6 months of active commuting or leisure-time exercise on measures of fibrin turnover in individuals who are overweight and obese. Ninety younger (20-40 years), sedentary, healthy women and men who are overweight and obese (BMI: 25-35 kg/m²) were randomised to 6 months of habitual lifestyle (CON, n=16), active commuting (BIKE, n=19), or leisure-time exercise of moderate (MOD, ∼50% VO₂peak reserve, n=31) or vigorous intensity (VIG, ∼70% VO₂peak reserve, n=24). Fasting blood samples (baseline and 3 and 6 months) were analysed for cholesterols and triglycerides, thrombin generation, prothrombin fragment 1 + 2, D-dimer, fibrin clot properties, and fibrinolytic activity. We observed no differences between CON, BIKE, MOD, and VIG during the intervention and no time effects for any of the variables measured despite increased VO₂peak in all exercise groups. We found no difference between CON and all exercise groups combined and no gender-specific effects of exercise. Our findings suggest that thrombin generation capacity, coagulation activation, fibrin clot structure, and lysability are unaffected by long-term active commuting and leisure-time exercise in women and men who are overweight and obese.

Pro-coagulant activity during exercise testing in patients with coronary artery disease

Background

Strenuous exercise may trigger myocardial infarction through increased pro-coagulant activity. We aimed to investigate whether patients referred for exercise testing, who were found to have angiographically verified coronary artery disease (CAD), have a more hypercoagulable profile during exercise testing than those without CAD.

Methods

Patients with symptoms of stable CAD were examined with exercise electrocardiography on bicycle ergometer. Venous blood samples were taken at rest and within 5 min after end of exercise. The following haemostatic variables were analyzed: tissue factor pathway inhibitor (TFPI) activity and antigen, prothrombin fragment 1 + 2 (F1 + 2), D-dimer and endogenous thrombin potential (ETP). All participants underwent conventional coronary angiography. CAD was defined as having any degree of atherosclerosis.

Results

Out of the 106 patients enrolled, 70 were found to have CAD. Mean exercise duration was 10:06 ± 4:11 min, with no significant differences between the groups. A significant increase from baseline to after exercise testing was observed in all measured markers in the total population (p ≤ 0.002 for all). In patients with angiographically verified CAD, total TFPI was significantly lower at baseline compared to patients without CAD (median value 67.4 and 76.6 ng/ml respectively, p = 0.027). However, no significant differences in changes of any of the measured markers during exercise were observed between the two groups.

Conclusion

Pro-coagulant activity increased during short-term strenuous exercise testing in patients with symptoms suggestive of CAD. However the hypercoagulable state observed, was not more pronounced in patients with angiographically verified CAD compared to patients without CAD. NCT01495091.

The integrated effect of moderate exercise on coronary heart disease

BACKGROUND

Moderate exercise is associated with a lower risk for coronary heart disease (CHD). A suitable integrated model of the CHD pathogenetic pathways relevant to moderate exercise may help to elucidate this association. Such a model is currently not available in the literature.

METHODS

An integrated model of CHD was developed and used to investigate pathogenetic pathways of importance between exercise and CHD. Using biomarker relative-risk data, the pathogenetic effects are representable as measurable effects based on changes in biomarkers.

RESULTS

The integrated model provides insight into higherorder interactions underlying the associations between CHD and moderate exercise. A novel 'connection graph' was developed, which simplifies these interactions. It quantitatively illustrates the relationship between moderate exercise and various serological biomarkers of CHD. The connection graph of moderate exercise elucidates all the possible integrated actions through which risk reduction may occur.

CONCLUSION

An integrated model of CHD provides a summary of the effects of moderate exercise on CHD. It also shows the importance of each CHD pathway that moderate exercise influences. The CHD risk-reducing effects of exercise appear to be primarily driven by decreased inflammation and altered metabolism.

The mechanisms by which antidepressants may reduce coronary heart disease risk

BACKGROUND

Depression is known to increase the risk for coronary heart disease (CHD) likely through various pathogenetic actions. Understanding the links between depression and CHD and the effects of mediating these links may prove beneficial in CHD prevention.

METHODS

An integrated model of CHD was used to elucidate pathogenetic pathways of importance between depression and CHD. Using biomarker relative risk data the pathogenetic effects are representable as measurable effects based on changes in biomarkers.

RESULTS

A 'connection graph' presents interactions by illustrating the relationship between depression and the biomarkers of CHD. The use of selective serotonin reuptake inhibitors (SSRIs) is postulated to have potential to decrease CHD risk. Comparing the 'connection graph' of SSRI's to that of depression elucidates the possible actions through which risk reduction may occur.

CONCLUSIONS

The CHD effects of depression appear to be driven by increased inflammation and altered metabolism. These effects might be mediated with the use of SSRI's.

How do high glycemic load diets influence coronary heart disease?

Background

Diet has a significant relationship with the risk of coronary heart disease (CHD). Traditionally the effect of diet on CHD was measured with the biomarker for low-density lipoprotein (LDL) cholesterol. However, LDL is not the only or even the most important biomarker for CHD risk. A suitably integrated view of the mechanism by which diet influences the detailed CHD pathogenetic pathways is therefore needed in order to better understand CHD risk factors and help with better holistic CHD prevention and treatment decisions.

Methods

A systematic review of the existing literature was conducted. From this an integrated CHD pathogenetic pathway system was constructed. CHD biomarkers, which are found on these pathways, are the only measurable data to link diet with these CHD pathways. They were thus used to simplify the link between diet and the CHD mechanism. Data were systematically analysed from 294 cohort studies of CHD biomarkers constituting 1 187 350 patients.

Results and discussion

The resulting integrated analysis provides insight into the higher-order interactions underlying CHD and high-glycemic load (HGL) diets. A novel “connection graph” illustrates the measurable relationship between HGL diets and the relative risks attributed to the important CHD serological biomarkers.

The “connection graph” vividly shows that HGL diets not only influence the lipid and metabolic biomarkers, but also the inflammation, coagulation and vascular function biomarkers in an important way.

Conclusion

A focus primarily on the low density lipoprotein cholesterol biomarker for CHD risk has led to the traditional guidelines of CHD dietary recommendations. This has however inadvertently led to HGL diets. The influence of HGL diets on the other CHD biomarkers is not always fully appreciated. Thus, new diets or other interventions which address the full integrated CHD impact, as shown in this paper, are required.

Modeling thrombin generation: plasma composition based approach

Thrombin has multiple functions in blood coagulation and its regulation is central to maintaining the balance between hemorrhage and thrombosis. Empirical and computational methods that capture thrombin generation can provide advancements to current clinical screening of the hemostatic balance at the level of the individual. In any individual, procoagulant and anticoagulant factor levels together act to generate a unique coagulation phenotype (net balance) that is reflective of the sum of its developmental, environmental, genetic, nutritional and pharmacological influences. Defining such thrombin phenotypes may provide a means to track disease progression pre-crisis. In this review we briefly describe thrombin function, methods for assessing thrombin dynamics as a phenotypic marker, computationally derived thrombin phenotypes versus determined clinical phenotypes, the boundaries of normal range thrombin generation using plasma composition based approaches and the feasibility of these approaches for predicting risk.