Influence of training on markers of platelet activation in response to a bout of heavy resistance exercise

Aerobic exercise training mitigates tumor growth and cancer-induced splenomegaly through modulation of non-platelet platelet factor 4 expression

Exercise training reduces the incidence of several cancers, but the mechanisms underlying these effects are not fully understood. Exercise training can affect the spleen function, which controls the hematopoiesis and immune response. Analyzing different cancer models, we identified that 4T1, LLC, and CT26 tumor-bearing mice displayed enlarged spleen (splenomegaly), and exercise training reduced spleen mass toward control levels in two of these models (LLC and CT26). Exercise training also slowed tumor growth in melanoma B16F10, colon tumor 26 (CT26), and Lewis lung carcinoma (LLC) tumor-bearing mice, with minor effects in mammary carcinoma 4T1, MDA-MB-231, and MMTV-PyMT mice. In silico analyses using transcriptome profiles derived from these models revealed that platelet factor 4 (Pf4) is one of the main upregulated genes associated with splenomegaly during cancer progression. To understand whether exercise training would modulate the expression of these genes in the tumor and spleen, we investigated particularly the CT26 model, which displayed splenomegaly and had a clear response to the exercise training effects. RT-qPCR analysis confirmed that trained CT26 tumor-bearing mice had decreased Pf4 mRNA levels in both the tumor and spleen when compared to untrained CT26 tumor-bearing mice. Furthermore, exercise training specifically decreased Pf4 mRNA levels in the CT26 tumor cells. Aspirin treatment did not change tumor growth, splenomegaly, and tumor Pf4 mRNA levels, confirming that exercise decreased non-platelet Pf4 mRNA levels. Finally, tumor Pf4 mRNA levels are deregulated in The Cancer Genome Atlas Program (TCGA) samples and predict survival in multiple cancer types. This highlights the potential therapeutic value of exercise as a complementary approach to cancer treatment and underscores the importance of understanding the exercise-induced transcriptional changes in the spleen for the development of novel cancer therapies.

The Acute and Chronic Effects of Resistance and Aerobic Exercise in Hemostatic Balance: A Brief Review

Hemostatic balance refers to the dynamic balance between blood clot formation (coagulation), blood clot dissolution (fibrinolysis), anticoagulation, and innate immunity. Although regular habitual exercise may lower the incidence of cardiovascular diseases (CVD) by improving an individual’s hemostatic profile at rest and during exertion, vigorous exercise may increase the risk of sudden cardiac death and venous thromboembolism (VTE). This literature review aims to investigate the hemostatic system’s acute and chronic adaptive responses to different types of exercise in healthy and patient populations. Compared to athletes, sedentary healthy individuals demonstrate similar post-exercise responses in platelet function and coagulatory and fibrinolytic potential. However, hemostatic adaptations of patients with chronic diseases in regular training is a promising field. Despite the increased risk of thrombotic events during an acute bout of vigorous exercise, regular exposure to high-intensity exercise might desensitize exercise-induced platelet aggregation, moderate coagulatory parameters, and up-regulate fibrinolytic potential via increasing tissue plasminogen activator (tPA) and decreasing plasminogen activator inhibitor (PAI-1) response. Future research might focus on combining different types of exercise, manipulating each training characteristic (frequency, intensity, time, and volume), or investigating the minimal exercise dosage required to maintain hemostatic balance, especially in patients with various health conditions.

Comparable effects of circuit and traditional resistance exercise on platelet α2bβ3 receptor and platelet activation and function

BACKGROUND

Resistance exercise induces thrombocytosis and increases platelet activation and function. These changes might be related to exercise variables including exercise intensity and type.

OBJECTIVE

We compared the effects of traditional resistance exercise (TRE) and circuit resistance exercise (CRE) on cellular markers of platelet activation and function.

METHODS

In this crossover study ten healthy male (mean±SD: age, 25.6±2.4 years) subjects performed TRE encompassed 3 sets of 10 repetitions at 100% of 10-RM (10 repetition maximum) for 6 exercises, and CRE protocols included 3 sets of 10 repetitions at 100% of 10-RM for all 6 exercises consecutively, in two separate weeks. To measure platelet indices, PAC1, CD41a, CD42b and CD62P three blood samples were taken before, immediately after exercise, and after 30 min recovery.

RESULTS

Lactate concentration, blood pressure, platelet count (PLT), and mean platelet volume (MPV) were significantly (p <  0.05) increased following both resistance exercise trials. Significant increases in PAC1, and CD62P; and significant reductions for CD42b and CD41a were detected following both REs (p <  0.05). However, changes in PAC1 and CD62P were significantly different between the two protocols (p <  0.05), with higher increases detected following CRE.

CONCLUSIONS

Acute RE increases platelet indices and platelet activation; and that CRE results in higher platelet activation than TRE, probably due to exercise-induced increases in shear stress.

Regular Resistance Training Enhances Fibrinolytic Potential but Does Not Affect Coagulation

PURPOSE

This study aimed to identify effects of an 8-wk, whole-body RT program on coagulation and fibrinolysis.

METHODS

Sixteen healthy women and men (23 ± 5 yr) completed an RT program three times per week for 8 wk. Exercises included 2-3 sets of 8-12 repetitions performed at approximately 60%-80% of a one repetition maximum. Strength, body composition, and body circumferences were assessed before and after training. Plasma samples were obtained before and after training, and analyzed for active tissue plasminogen activator (tPA activity), total tissue plasminogen activator (tPA antigen), active plasminogen activator inhibitor-1 (PAI-1 activity), total plasminogen activator inhibitor-1 (PAI-1 antigen), fibrinogen, and coagulation factors VII (FVII) and VIII (FVIII).

RESULTS

Significant increases in lean mass, arm and thigh circumferences, maximal chest press (PRE: 57.8 ± 37.5 kg, POST: 73.3 ± 43.2 kg), and leg press (PRE: 189.5 ± 96.0 kg, POST: 256.7 ± 97.9 kg) were observed (P < 0.05 for all). PAI-1 activity (PRE: 20.3 ± 32.5 IU·mL-1, POST 9.5 ± 20.9 IU·mL-1) and PAI-1 antigen decreased (PRE: 10.2 ± 9.0 ng·dL-1, POST: 7.2 ± 5.7 ng·dL-1; both, P < 0.05). No change in tPA activity or tPA antigen occurred. Fibrinogen, FVII, and FVIII did not change after training.

CONCLUSIONS

Inhibition of fibrinolysis was decreased after training, and coagulation was unaffected. These results suggest that regular RT may beneficially influence the risk of a thrombotic event. More research is warranted to understand the mechanisms through which RT affects hemostasis.

Management of venous thromboembolism in athletes

Venous thromboembolism (VTE) is a common condition with high associated morbidity and mortality. Athletes have unique VTE risk factors compared with the general population, and may have a higher than anticipated risk of thrombosis. Anticoagulant treatment poses additional challenges in athletes, as these individuals usually wish to return to sporting activities without delay. In addition, those athletes who engage in contact sports may have bleeding complications with extended anticoagulation. In this paper, we discuss VTE risk factors in athletes, the impact of exertion on haemostasis, measures which could be adopted to mitigate VTE risks in these highly active individuals and options to deal with bleeding risks from anticoagulation during injury-prone sporting activities.

A Pilot Study on the Effects of l-Carnitine and Trimethylamine-N-Oxide on Platelet Mitochondrial DNA Methylation and CVD Biomarkers in Aged Women

l-carnitine supplementation has been used for cardiovascular health protection for a long time. Recently, trimethylamine-N-oxide (TMAO), which is an end product of l-carnitine metabolism via the activity of microbiota, has been identified as a cardiovascular disease (CVD) biomarker. The aim of this study was to assess the effect of 6 months of l-carnitine supplementation in a group of aged women engaged in a regular physical training. Platelet mitochondrial DNA methylation, an emerging and innovative biomarker, lipid profile and TMAO levels have been measured. TMAO increased after l-carnitine supplementation (before 344.3 ± 129.8 ng/mL vs. after 2216.8 ± 1869.0 ng/mL; n = 9; paired t-test, p = 0.02). No significant effects on TMAO were exerted by training alone (n = 9) or by l-leucine supplementation (n = 12). TMAO levels after 6 months of l-carnitine supplementation were associated with higher low-density lipoprotein-cholesterol (LDL-c) (Spearman Rho = 0.518, p = 0.003) and total cholesterol (TC) (Spearman Rho = 0.407, p = 0.026) levels. l-carnitine supplementation increased D-loop methylation in platelets (+6.63%; paired t-test, p = 0.005). D-loop methylation was not directly correlated to the TMAO augmentation observed in the supplemented group, but its increase inversely correlated with TC (Pearson coefficient = −0.529, p = 0.029) and LDL-c (Pearson coefficient = −0.439, p = 0.048). This evidence supports the hypothesis that the correlation between l-carnitine, TMAO and atherosclerosis might be more complex than already postulated, and the alteration of mitochondrial DNA (mtDNA) methylation in platelets could be involved in the pathogenesis of this multifactorial disease.

Effect of training status on the changes in platelet parameters induced by short-duration exhaustive exercise

It is now well known that hemostasis is directly involved in the benefits induced by physical activity. It has recently been shown that the baseline mean platelet volume (MPV) may be a predictor of endurance performance. We aimed to explore whether platelet parameters are associated with VO2max as well as running duration and speed in a short-duration exhaustive exercise test. Thirty healthy male subjects (10 sedentary and 20 trained) performed an incremental running test until exhaustion. MPV, platelet distribution width (PDW), platelet (Plt) count, and plateletcrit (Pct) were determined before exercise, immediately after exercise and after 30' recovery. Training status did not produce any difference in the baseline levels or in the post-exercise increases found in all the parameters tested. VO2max, test duration, and running speed were not correlated with any baseline parameter. Although MPV was found to be a predictor of endurance performance in long-duration exercise, the results of the present study are consistent with the hypothesis that MPV may not be a significant marker of performance in short-duration exhaustive exercise. Likewise, more research is needed to ascertain whether platelet activation is a reliable performance predictor in other exercise settings.

Performance related factors are the main determinants of the von Willebrand factor response to exhaustive physical exercise

Background

Physical stress triggers the endothelium to release von Willebrand Factor (VWF) from the Weibel Palade bodies. Since VWF is a risk factor for arterial thrombosis, it is of great interest to discover determinants of VWF response to physical stress. We aimed to determine the main mediators of the VWF increase by exhaustive physical exercise.

Methods

105 healthy individuals (18–35 years) were included in this study. Each participant performed an incremental exhaustive exercise test on a cycle ergometer. Respiratory gas exchange measurements were obtained while cardiac function was continuously monitored. Blood was collected at baseline and directly after exhaustion. VWF antigen (VWF:Ag) levels, VWF collagen binding (VWF:CB) levels, ADAMTS13 activity and common variations in Syntaxin Binding Protein-5 (STXBP5, rs1039084 and rs9399599), Syntaxin-2 (STX2, rs7978987) and VWF (promoter, rs7965413) were determined.

Results

The median VWF:Ag level at baseline was 0.94 IU/mL [IQR 0.8–1.1] and increased with 47% [IQR 25–73] after exhaustive exercise to a median maximum VWF:Ag of 1.38 IU/mL [IQR 1.1–1.8] (p<0.0001). VWF:CB levels and ADAMTS13 activity both also increased after exhaustive exercise (median increase 43% and 12%, both p<0.0001). The strongest determinants of the VWF:Ag level increase are performance related (p<0.0001). We observed a gender difference in VWF:Ag response to exercise (females 1.2 IU/mL; males 1.7 IU/mL, p = 0.001), which was associated by a difference in performance. Genetic variations in STXBP5, STX2 and the VWF promoter were not associated with VWF:Ag levels at baseline nor with the VWF:Ag increase.

Conclusions

VWF:Ag levels strongly increase upon exhaustive exercise and this increase is strongly determined by physical fitness level and the intensity of the exercise, while there is no clear effect of genetic variation in STXBP5, STX2 and the VWF promoter.