Association of serum myokines and aerobic exercise training in patients with spinal cord injury: an observational study

Abstract

BackgroundPatients with spinal cord injury (SCI) have a higher prevalence of cardiovascular diseases compared to the healthy population. Aerobic exercise training is one of the recommended treatments. However, literature regarding the effect of aerobic training on patients with SCI is scarce. This study evaluated changes in parameters of exercise physiology and serum myokines immediately after exercise and after a training program among patients with SCI.MethodsMale patients with SCI and age- and sex-matched healthy individuals were recruited. Cardio-pulmonary exercise testing (CPET) was used to determine oxygen uptake at peak exercise and anaerobic threshold in both groups. The patients with SCI attended aerobic exercise training for 36 sessions within 12–16 weeks. Basic data, hemodynamic and exercise physiology parameters, and serum myokine (myostatin, IGF-1, and follistatin) concentrations were measured pre- and post-exercise in both groups, and were repeated in patients with SCI post-training.ResultsEleven patients with SCI underwent CPET and 5 completed the training. The 11 patients and 16 healthy adults had no differences in baseline serum myokine concentrations before CPET. Immediately after the CPET, the reference group had an 18 ± 19 % increase in serum IGF-1, while the patients had no observable myokine changes. After aerobic exercise training, the 5 patients had a 48 ± 18 % increase in serum myostatin compared to the pre-training level, although the body weight and exercise physiology parameters remained unchanged.ConclusionsAcute exercise to exhaustion in CPET results in an immediate increase in serum IGF-1 in healthy individuals while aerobic exercise training results in increased serum myostatin in patients with SCI.

Myostatin and Insulin-Like Growth Factor 1 Are Biomarkers of Muscle Strength, Muscle Mass, and Mortality in Patients on Hemodialysis

“…29 The positive association between myostatin and HGS observed in our patients must be discussed. The positive association observed between myostatin and HGS in different populations is still debated in the current literature, with some authors showing negative or no associations [30][31][32][33][34][35][36][37][38] and others showing a positive one. 11,[39][40][41][42][43] Such discrepancies in the literature could be explained, at least in part, by the difference in assays used to measure myostatin.…”

Myostatin as a Biomarker of Muscle Wasting and other Pathologies-State of the Art and Knowledge Gaps

“…Results of most recent studies suggest that physical exercise attenuates myostatin gene and protein expression in skeletal muscles directly after training [ 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 ], while a decrease of physical activity achieved by daily step reduction increased myostatin mRNA expression [ 135 ]. In most studies, serum myostatin levels were found to increase acutely after various exercise types (ultramarathon, aerobic, resistance and high-intensity training) [ 136 , 137 , 138 , 139 , 140 , 141 ], and decrease in the long term as a result of physical training [ 90 , 142 , 143 , 144 , 145 , 146 ]. Two studies noted an increase in circulating myostatin concentrations as a result of various (strength training, balance training, stretching exercises, walking recommendations) physical exercise over very long periods (6 and 12 months) [ 80 , 93 ].…”

Methodological Considerations Which Could Improve Spinal Cord Injury Research

“…With convenience sampling, individuals may not be representative of the larger population, thus, affecting both internal and external validity. Of the studies included, 32% (n = 10) used convenience sampling [3,4,6,9,10,12,14,18,19,23] (37% of non-case studies) while the remaining 68% (n = 21) did not report their sampling method (63% of non-case studies) [1, 5, 15, 20, 22, 25, 26, 28-30, 32, 34, 35, 37-41, 43, 44, 46]. Collectively, low sample size and convenience sampling limit the generalizability of findings to the SCI population as a whole.…”

“…Specifically, adequate control groups minimize the degree to which bias is involved in conducting and analyzing a study, affect the endpoints that can be studied, and ensure that the interventional effects are beyond normal variation to prevent under-or over-estimation of study effects [16]. Only 58% (n = 18) of the studies examined, and 67% of non-case studies, included a comparison group [1,3,6,9,12,15,20,22,23,25,26,30,33,34,38,40,41,43]. Additionally, only 67% (n = 12) of studies that included a comparison group were appropriately matched (examples: age, injury duration, etc.)…”

“…Additionally, only 67% (n = 12) of studies that included a comparison group were appropriately matched (examples: age, injury duration, etc.) to the experimental group [3,6,9,12,15,22,25,26,30,40,41,43].…”