Increased level of circulating cell-free mitochondrial DNA due to a single bout of strenuous physical exercise.
Author(s): Ohlsson L, Hall A, Lindahl H, Danielsson R, Gustafsson A, Lavant E, Ljunggren L
Publication: Eur J Appl Physiol, 2020, Vol. 120, Page 897-905
PubMed ID: 32088743 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to investigate the effects of exercise on levels of cell-free mitochondrial DNA (cf-mtDNA) in EDTA plasma and on levels of circulating leukocytes and soluble urokinase plasminogen activator receptor (suPAR) in blood.
Conclusion of Paper
Specimens obtained during exercise had higher levels of cf-mtDNA and higher leukocyte and lymphocyte counts and lower CD87 mean fluorescent intensity on neutrophils compared to specimens obtained prior to exercise. After the exercise period, cf-mtDNA levels continued to increase and CD87 mean fluorescent intensity on neutrophils was higher than baseline but levels of leukocytes were comparable to baseline levels and lymphocyte counts were lower than baseline. Plasma levels of suPAR changed in a biphasic pattern over the study period but only the 90 min rest specimen was significantly higher than baseline (P<0.05). The cf-mtDNA to cell-free nuclear DNA (cf-nDNA) ratio increased with exercise and during the subsequent rest period but the change was not significant.
Studies
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Study Purpose
The purpose of this study was to investigate the effects of exercise on levels of cf-mtDNA in EDTA plasma and on levels of circulating leukocytes and suPAR in blood. EDTA blood from eight healthy volunteers (4 male and 4 female) was obtained via peripheral venous catheter during cycling on an ergometer at five time points: arrival (after 15 min rest), at submaximal load (after 6 min or at heart rate of 125 beats/min) and maximal load (point of exhaustion), and 30 and 90 min after completion of exercise. Plasma was obtained from blood by centrifugation at 2000 x g for 10 min and stored at -80°C within 1 h of blood collection. suPAR levels in EDTA plasma were quantified using the suPARnosticTM immunoassay. DNA was isolated from EDTA plasma using the QIAmp 96 DNA Blood Kit and quantified by Nanodrop. cf-nDNA and cf-mtDNA were quantified by real-time PCR amplification of NADH dehydrogenase (ND2) and beta-2-microglobulin (β2M), respectively. Blood cells were counted in EDTA blood using a HemoCue WBC DIFF and HemoCue Hb 201 instruments after storage of blood in EDTA tubes at room temperature for 1-5 h. An aliquot of cells from blood were stained using antibodies against CD11b, CD87, CD14, and CD3 and counted by flow cytometry.
Summary of Findings:
Levels of cf-mtDNA increased during exercise and subsequent rest with significant increases from baseline found 30 min and 90 min after exercise (P<0.001 and P<0,01, respectively) but only non-significant increases in cf-nDNA were observed. The cf-mtDNA/cf-nDNA ratio increased with exercise and during the subsequent rest period but the change was not significant. Plasma levels of suPAR increased nonsignificantly with exercise, declined slightly during the first 30 min of rest, and then increased again but only the 90 min rest specimen had suPAR levels that were significantly higher than baseline (P<0.05). suPAR levels appeared to be weakly, negatively correlated with mean fluorescent intensity of CD87 on granulocytes (R=0.25) but the correlation was not significant (P=0.0625). The number of leukocytes was higher in specimens obtained at submaximal and maximal exercise (P<0.05, both) but was comparable to baseline in specimens obtained 30 and 90 min after exercise. Circulating lymphocytes counts were also higher in specimens obtained at maximal exercise than baseline (P<0.05) but lymphocyte counts were lower after 90 min rest than at baseline (P<0.01). Mean fluorescent intensity of CD87 on neutrophils was lower in specimens obtained during exercise than at baseline (P<0.001 at submaximal and maximal) but was higher in specimens obtained 30 min after exercise than in baseline specimens (P<0.01).
Biospecimens
Preservative Types
- Frozen
- None (Fresh)
Diagnoses:
- Normal
Platform:
Analyte Technology Platform DNA Real-time qPCR Cell count/volume Hematology/ auto analyzer Cell count/volume Flow cytometry Protein Immunoassay Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Acquisition Time of biospecimen collection Baseline
Submaximal exercise
At maximal exercise
30 min post-exercise
90 min post- exercise
Real-time qPCR Specific Targeted nucleic acid ND2
β2M