Changes in plasma hydroxyproline and plasma cell-free DNA concentrations after higher- versus lower-intensity eccentric cycling.
Author(s): Mavropalias G, Calapre L, Morici M, Koeda T, Poon WCK, Barley OR, Gray E, Blazevich AJ, Nosaka K
Publication: Eur J Appl Physiol, 2021, Vol. 121, Page 1087-1097
PubMed ID: 33439308 PubMed Review Paper? No
Purpose of Paper
This paper compared levels of creatine kinase (CK) activity, plasma hydroxyproline, cell-free DNA (cfDNA), and cell-free copies of the methylated HOXD4 promoter in specimens obtained from healthy men before, immediately after and 24, 48, and 72 h after exercise (high intensity (HI) or low intensity (LI) eccentric cycling).
Conclusion of Paper
Blood CK activity and plasma hydroxyproline levels were higher than baseline in whole blood specimens collected 24 h post-exercise; and while CK levels then returned to baseline, hydroxyproline levels were higher than baseline at all subsequent collection timepoints. Importantly, CK activity and plasma hydroxyproline levels were comparable between specimens from patients in the HI and LI group at all timepoints. In contrast, average plasma cfDNA levels were 2.3-fold higher than baseline immediately post-exercise in the HI group, but were comparable to baseline at all other timepoints and in all timepoints within the LI group. The skeletal muscle-specific methylation of HOXD4 was not detected in plasma (although it was only investigated in five patients from the HI group).
Studies
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Study Purpose
This study compared levels of CK activity, plasma hydroxyproline, cfDNA and cell-free copies of the methylated HOXD4 promoter in specimens obtained from healthy men before, immediately after and 24, 48, and 72 h after exercise via HI or LI eccentric cycling. After 1 min of eccentric cycling for familiarization, eleven subjects performed five eccentric cycling sessions of 1-min at 20% of peak output (HI) and nine other men performed five eccentric cycling sessions of 4 min at 5% of peak output (LI). Heart rate was continuously monitored during exercise. EDTA blood was collected from each man before and 0, 24, 48 and 72 h after exercise. Creatinine kinase activity was measured in whole blood using test strips and an autoanalyzer. Plasma was separated by centrifugation at 1600 g for 10 min followed by 2000 g for 10 min and then stored at -80°C. Plasma levels of hydroxyproline were quantified by a colorimetric assay. cfDNA was extracted from plasma using the QIAamp Circulating Nucleic Acid Kit and quantified by ddPCR amplification of the AR and BAP1 genes. Five cfDNA extracts from patients in the HI group were analyzed using a 2100 Bioanalyzer systems and by ddPCR amplification of the HOXD4 promoter.
Summary of Findings:
CK activity was higher than baseline in whole blood specimens collected 24 h post-exercise (P=0.029), but there was no difference between HI and LI groups or relative to baseline at any other timepoint. Plasma hydroxyproline levels were higher than baseline 24-72 h post-exercise (P<0.001, all); levels increased until 24 h post-exercise and then leveled off. Importantly, the change in hydroxyproline relative to baseline was similar in both exercise groups. In contrast, average plasma cfDNA levels were 2.3-fold higher than baseline immediately post-exercise in the HI group (P<0.001), but not the LI group, which resulted in a significant difference in plasma cfDNA concentrations between groups immediately after exercise (P=0.002). By 24 h post exercise, plasma cfDNA levels in the high intensity group were comparable to baseline. The skeletal muscle-specific methylation of HOXD4 was not detected in the plasma of patients in the HI group. Average heart rate was higher in the HI exercise group compared to the LI group.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Normal
Platform:
Analyte Technology Platform DNA Digital PCR Protein Clinical chemistry/auto analyzer Small molecule Colorimetric assay Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Preaquisition Diagnosis/ patient condition High Intensity exercise
Low intensity exercise
Biospecimen Acquisition Time of biospecimen collection Immediately before exercise
Immediately after exercise
24 h after exercise
48 h after exercise
72 h after exercise
Digital PCR Specific Targeted nucleic acid HOXD4 promoter methylation
AR
BAP