Vigorous exercise acutely changes platelet and B-lymphocyte CD39 expression

Clinical effects and biological mechanisms of exercise on lumbar disc herniation

Lumbar Disc Herniation (LDH) is a syndrome in which lumbar disc degeneration, rupture of the annulus fibrosus, and herniation of the nucleus pulposus irritate and compress the nerve roots and cauda equina, resulting in the main manifestations of lumbar pain and/or lower extremity pain. There is evidence in various clinical areas that exercise is effective in treating LDH, and exercise intervention for more than 2 weeks reduces disease activity in LDH. However, the mechanism of exercise's action in reducing disease activity in LDH is unclear. In this article, we first summarize and highlight the effectiveness of exercise in treating LDH and provide guideline recommendations regarding exercise type, intensity, frequency, and duration. Then, we integrate the existing evidence and propose biological mechanisms for the potential effects of exercise on neuromechanical compression, inflammatory chemical stimuli, and autoimmune responses from the perspective of LDH pathogenesis as an entry point. However, a large body of evidence was obtained from non-LDH populations. Future research needs to investigate further the proposed biological mechanisms of exercise in reducing disease activity in LDH populations. This knowledge will contribute to the basic science and strengthen the scientific basis for prescribing exercise therapy for the routine clinical treatment of LDH.

Effects of physical exercise on the functionality of human nucleotidases: A systematic review

Nucleotidases contribute to the regulation of inflammation, coagulation, and cardiovascular activity. Exercise promotes biological adaptations, but its effects on nucleotidase activities and expression are unclear. The objective of this study was to review systematically the effects of exercise on nucleotidase functionality in healthy and unhealthy subjects. The MEDLINE, EMBASE, Cochrane Library, and Web of Science databases were searched to identify, randomized clinical trials, non-randomized clinical trials, uncontrolled clinical trials, quasi-experimental, pre-, and post-interventional studies that evaluated the effects of exercise on nucleotidases in humans, and was not limited by language and date. Two independent reviewers performed the study selection, data extraction, and assessment of risk of bias. Of the 203 articles identified, 12 were included in this review. Eight studies reported that acute exercise, in healthy and unhealthy subjects, elevated the activities or expression of nucleotidases. Four studies evaluated the effects of chronic training on nucleotidase activities in the platelets and lymphocytes of patients with metabolic syndrome, chronic kidney disease, and hypertension and found a decrease in nucleotidase activities in these conditions. Acute and chronic exercise was able to modify the blood plasma and serum levels of nucleotides and nucleosides. Our results suggest that short- and long-term exercise modulate nucleotidase functionality. As such, purinergic signaling may represent a novel molecular adaptation in inflammatory, thrombotic, and vascular responses to exercise.

Purinergic signaling as a new mechanism underlying physical exercise benefits: a narrative review

In the last years, it has become evident that both acute and chronic physical exercise trigger responses/adaptations in the purinergic signaling and these adaptations can be considered one important mechanism related to the exercise benefits for health improvement. Purinergic system is composed of enzymes (ectonucleotidases), receptors (P1 and P2 families), and molecules (ATP, ADP, adenosine) that are able to activate these receptors. These components are widely distributed in almost all cell types, and they respond/act in a specific manner depending on the exercise types and/or intensities as well as the cell type (organ/tissue analyzed). For example, while acute intense exercise can be associated with tissue damage, inflammation, and platelet aggregation, chronic exercise exerts anti-inflammatory and anti-aggregant effects, promoting health and/or treating diseases. All of these effects are dependent on the purinergic signaling. Thus, this review was designed to cover the aspects related to the relationship between physical exercise and purinergic signaling, with emphasis on the modulation of ectonucleotidases and receptors. Here, we discuss the impact of different exercise protocols as well as the differences between acute and chronic effects of exercise on the extracellular signaling exerted by purinergic system components. We also reinforce the concept that purinergic signaling must be understood/considered as a mechanism by which exercise exerts its effects.

Acute moderate-intensity aerobic exercise promotes purinergic and inflammatory responses in sedentary, overweight and physically active subjects

NEW FINDING

What is the central question of this study? How does moderate-intensity aerobic exercise affect the behaviour of purinergic enzymes in sedentary, overweight and physically active subjects? What is the relationship between purinergic and inflammatory responses triggered by exercise? What is the main finding and its importance? Moderate-intensity aerobic exercise modifies the activity of purinergic enzymes and the levels of nucleotides and nucleosides. These results are similar in subjects with different biological characteristics. 5'-Nucleotidase activity and adenosine levels are associated with inflammatory responses. This study suggests that a purinergic pathway is related to the inflammatory responses triggered by exercise.

ABSTRACT

Purinergic signalling is a mechanism of extracellular communication that modulates events related to exercise, such as inflammation and coagulation. Herein, we evaluated the effects of acute moderate-intensity exercise on the activities of purinergic enzymes and plasma levels of adenine nucleotides in individuals with distinct metabolic characteristics. We analysed the relationship between purinergic parameters, inflammatory responses and cardiometabolic markers. Twenty-four healthy males were assigned to three groups: normal weight sedentary (n = 8), overweight sedentary (n = 8) and normal weight physically active (n = 8). The volunteers performed an acute session of moderate-intensity aerobic exercise on a treadmill at 70% of V ̇ O 2 peak ; blood samples were drawn at baseline, immediately post-exercise and at 1 h post-exercise. Immediately post-exercise, all subjects showed increases in ATP, ADP, AMP and p-nitrophenyl thymidine 5'-monophosphate hydrolysis, while AMP hydrolysis remained increased at 1 h after exercise. High-performance liquid chromatography analysis demonstrated lower levels of ATP and ADP at post- and 1 h post-exercise in all groups. Conversely, adenosine and inosine levels increased at post-exercise, but only adenosine remained augmented at 1 h after exercise in all groups. With regard to inflammatory responses, the exercise protocol increased tumour necrosis factor α (TNF-α) and interleukin 8 (IL-8) concentrations in all subjects, but only TNF-α remained elevated at 1 h after exercise. Significant correlations were found between the activity of 5'-nucleotidase, adenosine levels, V ̇ O 2 peak , triglyceride, TNF-α and IL-8 levels. Our findings suggest a purinergic signalling pathway that participates, at least partially, in the inflammatory responses triggered by acute moderate-intensity exercise. The response of soluble nucleotidases to acute moderate exercise appears to be similar between subjects of different biological profiles.

Aronia juice consumption prior to half-marathon race can acutely affect platelet activation in recreational runners

Long-distance running, especially in non-professional runners, can increase cardiac arrest risk by enhancing platelet activation and aggregation. Polyphenols can exert cardioprotective effects by positively influencing platelet function. This study aimed to examine the acute effects of polyphenol-rich aronia juice consumption, before simulation of a half-marathon race, on platelet activation and aggregation with leukocytes in recreational runners. In this acute crossover study,10 healthy male runners (age 30.8 ± 2.3 years) consumed breakfast with 200 mL of aronia juice or 200 mL of placebo. They warmed-up and ran a simulated half-marathon race (21.1 km). Blood was collected at baseline, and at 15 min, 1 h, and 24 h after the run. All variables were analyzed with 4 (time) × 2 (group) ANOVA with repeated measures on both factors. Results revealed a significant effect of group on platelet activation parameters: P-selectin and GPIIb-IIIa expressions significantly decreased in the aronia group compared with the placebo group (F_[1,9] = 10.282, p = 0.011 and F_[1,9] = 7.860, p = 0.021, respectively). The effect of time was significant on both platelet aggregation markers: platelet-monocyte and platelet-neutrophil aggregates were significantly lower after the race (F_[3,7] = 4.227, p = 0.014 and F_[3,7] = 70.065, p = 0.000, respectively), with changes more pronounced in the later. All effects remained when platelets were exposed to an agonist. These results suggest that aronia consumption could counteract the half-marathon race-induced changes in platelet function. Novelty Aronia juice consumption significantly decreased the expression of platelet activation markers but did not affect platelet aggregation. The race itself did significantly reduce platelet-neutrophil aggregation. Aronia juice may serve as a supplement beverage for recreational runners to alleviate enhanced platelet reactivity caused by prolonged running.

Altered extracellular ATP, ADP, and AMP hydrolysis in blood serum of sedentary individuals after an acute, aerobic, moderate exercise session

Nucleotidases participate in the regulation of physiological and pathological events, such as inflammation and coagulation. Exercise promotes distinct adaptations, and can influence purinergic signaling. In the present study, we investigated soluble nucleotidase activities in the blood serum of sedentary young male adults at pre- and post-acute moderate aerobic exercise. In addition, we evaluated how this kind of exercise could influence adenine nucleotide concentrations in the blood serum. Sedentary individuals were submitted to moderate aerobic exercise on a treadmill; blood samples were collected pre- and post-exercise, and serum was separated for analysis. Results showed increases in ATP, ADP, and AMP hydrolysis post-exercise, compared to pre-exercise values. The ecto-nucleotide pyrophosphatase/phosphodiesterase was also evaluated, showing an increased activity post-exercise, compared to pre-exercise. Purine levels were analyzed by HPLC in the blood serum, pre- and post-exercise. Decreased levels of ATP and ADP were found post-exercise, in contrast with pre-exercise values. Conversely, post-exercise levels of adenosine and inosine increased compared to pre-exercise levels. Our results indicate an influence of acute exercise on ATP metabolism, modifying enzymatic behavior to promote a protective biological environment.

Exercise intensity modulates the appearance of circulating microvesicles with proangiogenic potential upon endothelial cells

The effect of endurance exercise on circulating microvesicle dynamics and their impact on surrounding endothelial cells is unclear. Here we tested the hypothesis that exercise intensity modulates the time course of platelet (PMV) and endothelial-derived (EMV) microvesicle appearance in the circulation through hemodynamic and biochemical-related mechanisms, and that microvesicles formed during exercise would stimulate endothelial angiogenesis in vitro. Nine healthy young men had venous blood samples taken before, during, and throughout the recovery period after 1 h of moderate [46 ± 2% maximal oxygen uptake (V̇o_2max)] or heavy (67 ± 2% V̇o_2max) intensity semirecumbent cycling and a time-matched resting control trial. In vitro experiments were performed by incubating endothelial cells with rest and exercise-derived microvesicles to examine their effects on cell angiogenic capacities. PMVs (CD41⁺) increased from baseline only during heavy exercise (from 21 ± 1 × 10³ to 55 ± 8 × 10³ and 48 ± 6 × 10³ PMV/μl at 30 and 60 min, respectively; P < 0.05), returning to baseline early in postexercise recovery (P > 0.05), whereas EMVs (CD62E⁺) were unchanged (P > 0.05). PMVs were related to brachial artery shear rate (r² = 0.43) and plasma norepinephrine concentrations (r² = 0.21) during exercise (P < 0.05). Exercise-derived microvesicles enhanced endothelial proliferation, migration, and tubule formation compared with rest microvesicles (P < 0.05). These results demonstrate substantial increases in circulating PMVs during heavy exercise and that exercise-derived microvesicles stimulate human endothelial cells by enhancing angiogenesis and proliferation. This involvement of microvesicles may be considered a novel mechanism through which exercise mediates vascular healing and adaptation.

Effects of Physical (In)activity on Platelet Function

As platelet activation is closely related to the liberation of growth factors and inflammatory mediators, platelets play a central role in the development of CVD. Virtually all cardiovascular risk factors favor platelet hyperreactivity and, accordingly, also physical (in)activity affects platelet function. Within this paper, we will summarize and discuss the current knowledge on the impact of acute and habitual exercise on platelet function. Although there are apparent discrepancies regarding the reported effects of acute, strenuous exercise on platelet activation, a deeper analysis of the available literature reveals that the applied exercise intensity and the subjects' cardiorespiratory fitness represent critical determinants for the observed effects. Consideration of these factors leads to the summary that (i) acute, strenuous exercise can lead to platelet activation, (ii) regular physical activity and/or physical fitness diminish or prevent platelet activation in response to acute exercise, and (iii) habitual physical activity and/or physical fitness also favorably modulate platelet function at physical rest. Notably, these effects of exercise on platelet function show obvious similarities to the well-recognized relation between exercise and the risk for cardiovascular events where vigorous exercise transiently increases the risk for myocardial infarction and a physically active lifestyle dramatically reduces cardiovascular mortality.

Physical training normalizes nucleotide hydrolysis and biochemical parameters in blood serum from streptozotocin-diabetic rats

Ectonucleotidases and the nucleotide metabolism have been implicated as important regulators in diabetes disease. We evaluated the ectonucleotidase activities and biochemical parameters in blood serum of streptozotocin (STZ)-induced diabetic rats submitted a physical training protocol. We observed a raise in ATP, ADP, AMP and p-Nph-5'-TMP hydrolysis rate and in the levels of cholesterol and triglycerides in rat blood serum, after 30 days of diabetes induction. However, in serum of rats submitted a physical training protocol by forced swimming, both the nucleotide hydrolysis rate and the lipids levels returned to the control values. Considering that diabetes leads to multiple pathophysiological alterations, the modulations observed in ectonucleotidase activities may be part of the events involved in these alterations. Then the physical training is a very important way to control the vascular alterations developed in diabetes.

A influência da intensidade do exercício físico aeróbio no processo aterosclerótico

A aterosclerose é um processo inflamatório crônico e degenerativo que acomete os vasos, sendo caracterizada pelo acúmulo de lipídeos no espaço subendotelial da íntima, acúmulo de células inflamatórias e elementos fibrosos. A oxidação de LDL-c parece ser o principal evento para o início da aterosclerose. O exercício físico aeróbio melhora os sistemas de defesa orgânicos contra aterosclerose, diminuindo o estresse oxidativo e aumentando a síntese de enzimas antioxidantes; aumento da vasodilatação via óxido nítrico (NO) e óxido nítrico sintase endotelial (eNOS) e diminuição da inflamação sistêmica com produção de citocinas pró-inflamatórias e aumento de fatores anti-inflamatórios. Porém, de maneira aguda, o exercício aeróbio de alta intensidade aumenta o risco de desenvolvimento de eventos cardiovasculares e, de forma crônica, pode atuar negativa ou positivamente na prevenção do processo aterosclerótico.

Platelet thromboxane A2 secretion in patients with major depression responsive to electroconvulsive therapy

OBJECTIVE

To determine a) whether clinical response to electroconvulsive therapy (ECT) is associated with decreased platelet activation in patients with major depressive disorder (MDD) and b) if any medical/demographic characteristics predict response to ECT or changes in platelet activation. Increased platelet activation may underlie the increased risk of coronary artery disease (CAD) in patients with MDD.

METHODS

Before their first and sixth ECT treatments, study patients (n = 44) completed the Beck Depression Inventory (BDI) to assess the severity of depressive symptoms. Activity of the platelet thromboxane (TBX) A(2) pathway was assessed by measuring the morning spot urinary concentrations of 11-dehydroxy-thromboxane B(2) (11-D-TBX B(2)), a major metabolite of platelet-derived TBX A(2).

RESULTS

Multivariate logistic regression analyses revealed that improvement on the BDI was significantly more likely in patients without a history of hypertension (p = .02) and in patients who were prescribed a greater number of "platelet-altering" medications (p = .03). During a course of ECT, a decrease in urinary 11-D-TBX B(2) was significantly more likely to occur in ECT nonresponders (p = .01) and younger patients (p = .02).

CONCLUSIONS

Clinical response to ECT coadministered may not be associated with decreases in platelet-derived TBX. Future studies will confirm which somatic "antidepression" treatments offer optimal thrombovascular benefits for depressed patients with multiple risk factors for, or clinically evident, cerebral disease or CAD.

CD39 activity correlates with stage and inhibits platelet reactivity in chronic lymphocytic leukemia

Background

Chronic lymphocytic leukemia (CLL) is characterized by accumulation of mature appearing lymphocytes and is rarely complicated by thrombosis. One possible explanation for the paucity of thrombotic events in these patients may be the presence of the ecto-nucleotidase CD39/NTDPase-1 on the surface of the malignant cells in CLL. CD39 is the major promoter of platelet inhibition in vivo via its metabolism of ADP to AMP. We hypothesize that if CD39 is observed on CLL cells, then patients with CLL may be relatively protected against platelet aggregation and recruitment and that CD39 may have other effects on CLL, including modulation of the disease, via its metabolism of ATP.

Methods

Normal and malignant lymphocytes were isolated from whole blood from patients with CLL and healthy volunteers. Enzyme activity was measured via radio-TLC assay and expression via FACS. Semi-quantititative RT-PCR for CD39 splice variants and platelet function tests were performed on several samples.

Results

Functional assays demonstrated that ADPase and ATPase activities were much higher in CLL cells than in total lymphocytes from the normal population on a per cell basis (p-value < 0.00001). CD39 activity was elevated in stage 0–2 CLL compared to stage 3–4 (p < 0.01). FACS of lymphocytes demonstrated CD39 expression on > 90% of normal and malignant B-lymphocytes and ~8% of normal T-lymphocytes. RT-PCR showed increased full length CD39 and splice variant 1.5, but decreased variant 1.3 in CLL cells. Platelet function tests showed inhibition of platelet activation and recruitment to ADP by CLL cells.

Conclusion

CD39 is expressed and active on CLL cells. Enzyme activity is higher in earlier stages of CLL and decreased enzyme activity may be associated with worsening disease. These results suggest that CD39 may play a role in the pathogenesis of malignancy and protect CLL patients from thrombotic events.

Intravascular ADP and soluble nucleotidases contribute to acute prothrombotic state during vigorous exercise in humans

Extracellular ATP and ADP trigger vasodilatatory and prothrombotic signalling events in the vasculature. Here, we tested the hypothesis that nucleotide turnover is activated in the bloodstream of exercising humans thus contributing to the enhanced platelet reactivity and haemostasis. Right atrial, arterial and venous blood samples were collected from endurance-trained athletes at rest, during submaximal and maximal cycle ergometer exercise, and after early recovery. ATP-specific bioluminescent assay, together with high-performance liquid chromatographic analysis, revealed that plasma ATP and ADP concentrations increased up to 2.5-fold during maximal exercise. Subsequent flow cytometric analysis showed that plasma from exercising subjects significantly up-regulated the surface expression of P-selectin in human platelets and these prothrombotic effects were diminished after scavenging plasma nucleotides with exogenous apyrase. Next, using thin layer chromatographic assays with [gamma-(32)P]ATP and (3)H/(14)C-labelled nucleotides, we showed that two soluble nucleotide-inactivating enzymes, nucleotide pyrophosphatase/phosphodiesterase and nucleoside triphosphate diphosphohydrolase, constitutively circulate in human bloodstream. Strikingly, serum nucleotide pyrophosphatase and hydrolase activities rose during maximal exercise by 20-25 and 80-100%, respectively, and then declined after 30 min recovery. Likewise, soluble nucleotidases were transiently up-regulated in the venous blood of sedentary subjects during exhaustive exercise. Human serum also contains 5'-nucleotidase, adenylate kinase and nucleoside diphosphate (NDP) kinase; however, these activities remain unchanged during exercise. In conclusion, intravascular ADP significantly augments platelet activity during strenuous exercise and these prothrombotic responses are counteracted by concurrent release of soluble nucleotide-inactivating enzymes. These findings provide a novel insight into the mechanisms underlying the enhanced risk of occlusive thrombus formation under exercising conditions.

HIV infection is associated with increased NTPDase activity that correlates with CD39-positive lymphocytes

Infection with the human immunodeficiency virus (HIV) results in alterations in immune cells such as an increase or decrease of cytokine secretion and immunodeficiency. HIV causes a state of chronic cellular activation that can induce apoptosis in lymphocyte T-helpers, making the patient susceptive to opportunistic infections. The biochemical mechanisms involved in this immune response to HIV have been researched. Here, we have shown for the first time that ATP and ADP hydrolysis are essential for the immune response to HIV. Our results clearly indicate an increase of NTPDase-1 (EC 3.6.1.5) activity in lymphocytes of HIV-positive patients, confirmed by an enhanced CD39 expression on its surface. These results suggest that NTPDase-1 may be important to keep an adequate balance between the generation and consumption of ATP and to preserve cellular integrity and immune response to the HIV infection.