Two-peaked increase of serum myosin heavy chain-α after triathlon suggests heart muscle cell death

Abstract

ObjectiveIt has been suggested that the mechanism behind cardiac troponin elevation after strenuous exercise is passage through a cell membrane with changed permeability rather than myocardial cell death. We hypothesised that an increase of cardiac specific myosin heavy chain-alpha (MHC-α; 224 kDa compared with cardiac troponin T’s (cTnT) 37 kDa) could hardly be explained by passage through a cell membrane.MethodsBlood samples were collected from 56 athletes (15 female, age 42.5±9.7, range 24–70 years) before, directly after and on days 1–8 after an Ironman. Biomarkers (C reactive protein (CRP), cTnT, creatine kinase (CK), MHC-α, myoglobin (MG), creatinine (C) and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) were measured.ResultsThe course of MHC-α concentration (µg/L) was 1.33±0.53 (before), 2.57±0.78 (directly after), 1.51±0.53 (day 1), 2.74±0.55 (day 4) and 1.83±0.76 (day 6). Other biomarkers showed a one-peaked increase with maximal values either directly after the race or at day 1: cTnT 76 ± 80 ng/L (12–440; reference<15), NT-proBNP 776±684 ng/L (92–4700; ref.<300), CK 68±55 µkat/L (5–280; ref.<1.9), MG 2088±2350 µg/L (130–17 000; ref.<72) and creatinine 100±20 µmol/L (74–161; ref.<100), CRP 49±23 mg/L (15–119; ref.<5).ConclusionMHC-α exhibited a two-peaked increase which could represent a first release from the cytosolic pool and later from cell necrosis. This is the first investigation of MHC-α plasma concentration after exercise.

Biochemical markers after the Norseman Extreme Triathlon

“…The findings of greatest clinical interest are those in WBC, CRP, AST, CK and NT-proBNP because the results would indicate pathology in the resting state in a medical examination [22][23][24][25][26]. This is in line with previous studies on Ironman distance triathlons [7][8][9].…”

“…Norseman (8 [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] mg/L, p < 0.001) with a clinically significant increase the following day (39 mg/L, p < 0.001 compared to baseline, < 0.001 compared to finish line). AST had increased at the finish line (99 [74-136] U/L, p < 0.001) but it increased to even higher values the day after the race (142 [99-191] U/L, p < 0.001 compared to baseline, p < 0.05 compared to finish line).…”

“…Prolonged exercise is known to cause changes in common biomarkers [4][5][6]. There are major changes in serval biomarkers after Ironman distance triathlons [7][8][9]. Knowledge about what range of change can be considered "normal" regarding the most common biomarkers used in clinical diagnostics is therefore warranted, as this will allow for the findings in patients who have participated in these types of competitions to be evaluated [10,11].…”

“…We examined Creatinine Kinase (CK), N-terminal pro Brain Natriuretic Peptide (NT-proBNP), Creatinine, C-reactive protein (CRP), White blood cells (WBC), Thrombocytes, Hemoglobin (Hb), Sodium (Na + ), Potassium (K + ), Calcium (Ca 2+ ), Magnesium (Mg 2+ ), Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), Triiodothyronine (T3), Thyroxine (T4) and Thyroid Stimulating Hormone (TSH), covering heart function, inflammation markers, markers of cell injury, electrolytes and thyroid function [4][5][6][7][8][9][14][15][16][17][18][19][20]. For comparison of the impact of different types of triathlons we have also examined the same biomarkers after an Olympic triathlon.…”

Aerobic capacity predict skeletal but not cardiac muscle damage after triathlon – the Iron(WO)man study

“…The absence of an association between aerobic capacity and markers for cardiac muscle damage was surprising given the well know cardio-protective health effects of having a high aerobic fitness. We have previously reported that nearly all of the athletes showed pathological values of cTnT (98%) and NT-proBNP (89%) after finishing the race 16 but the clinical value of these observations are under debate. The debate centers on whether the elevated biomarkers seen after ultra-endurance races reflect true pathological changes or if they are a part of the normal physiological response 17,18 .…”