gms | German Medical Science

Objective: The aim of the present study was to investigate the time-course response to surface electro-myostimulation (EMS) on bone and muscle biomarkers in men with recent spinal cord injury (SCI). Our hypothesis was that EMS might produce a release of both muscle and bone formation biomarkers beyond the basal levels, together with a reduction of muscle and bone destruction biomarkers.

Material/Methods: Seven recent spinal cord injured men (stage A according to ASIA scale after a neurophysiological examination) participated in this investigation after giving informed consent. The mean (±SD) time post injury, age, weight and height were 5 (±1.2) weeks, 39 (±13) yr, 73.6 (±5.7) kg, and 1.77 (±0.1) m; respectively. Blood samples were drawn at basal conditions, immediately after EMS (0 min) and 15 min, 30 min, 24 h and 48 h following the EMS protocol. Blood serum total testosterone (T) was measured by chemiluminescent microparticle immunoassay using ARCHITECT i2000SR (Abbott Laboratories S.A, Madrid, Spain). Serum cortisol (C) was measured by microparticle enzyme immunoassay using ARCHITECT c4000 (Abbott Laboratories S.A, Madrid, Spain). Serum osteocalcin (O) was analyzed by radioimmunoassay using a Diasource kit (Barcelona, Spain). Serum type I collagen C-telopeptide (CT) was analyzed by electrochemiluminescence using the E 170 module for MODULAR ANALYTICS (Roche Diagnostics, S.L., Madrid, Spain). Surface EMS of the quadriceps femoris was applied on a supine position at knee angles of 10º, 30º, 60º and 85º using a commercial stimulator. Values of pulse duration, pulse width, frequency and current amplitude were 6 s, 200 µs, 30 Hz, and 10 to 140 mA; respectively. A total of 20 contractions per knee angle were applied during 47 minutes. The changes in T, C, O and CT over time from basal were studied using analysis of variance with repeated measures (SPSS for Windows, v. 16.0, Inc., Chicago, IL). A level of P<0.05 was accepted as significant.

Results: The ANOVA did not revealed any significant difference on T, C, T/C ratio or O between any time points after EMS (Table 1 [Tab. 1]). On the other hand, EMS induced significant changes on CT levels and O/CT ratio when measured immediately, 15 min and 30 min after EMS.

Conclusion: This is the first study to provide some insight to the acute EMS effects on muscle and bone biomarkers in patients with such a recent SCI. In spite of the relatively low intensity EMS protocol used, it was shown to be effective to produce positive alteration in bone metabolism markers (i.e. decrease in CT). Muscle hormones were unaffected since the required contraction threshold [1] to induce positive effects on muscle (i.e. increase hypertrophy or reduce atrophy) was probably not reached.