Increased endothelin and creatine kinase after electrical stimulation of paraplegic muscle

Abstract

The purpose of this study was to assess changes in creatine kinase (CK) and endothelin (ET) in individuals with spinal cord injury (SCI) after computerized functional electrical stimulation leg ergometry (CFES LE). Eight subjects (7 male and 1 female) with complete spinal cord lesions (C7 to L1) completed zero-loaded CFES LE tests at baseline, after 3, 6, and 12 wk of CFES LE training (30 min, 3 times/wk), and also after detraining (DT) (n = 5). Venous blood samples were drawn 24, 48, and 72 h after CFES LE for measurement of ET and CK. The CK response was largest (peak CK) 72 h after baseline tests (28.2 +/- 6.0 to 895.7 +/- 345.9 ktals/l) and was no different from baseline by weeks 3, 6, and 12. After DT, CK was similar before and after CFES LE (153.8 +/- 19.0 and 189.7 +/- 34.5 ktals/l, respectively). CFES LE also significantly increased peak ET after baseline (from 11.7 +/- 1.5 to 18.0 +/- 2.5 pg/ml). During the subsequent training, peak ET remained significantly higher than the baseline value at weeks 3, 6, and 12 (20.2 +/- 1.8, 18.0 +/- 1.1, and 16.9 +/- 2.2 pg/ml, respectively). After DT, peak ET increased significant relationship (r = 0.44) existed between ln peak CK activity and peak ET. In summary, the increase in circulating ET in spinal cord-injured individuals may have implications for baroreceptor function and therefore blood pressure control in SCI. Further research into CFES LE, ET, and baroreceptor function in SCI is warranted.

Surface electrical stimulation of skeletal muscle after spinal cord injury

“…37,38 This may explain the elevated plasma creatine kinase (CK) activity recently reported for SCI patients after a bout of FES. 39 While plasma CK is not a direct marker of muscle cell injury, its elevation and the prolonged recovery of force after surface ES found in this study suggest that the contribution of contraction induced ®ber disruption to`fatigue' after SCI needs to be examined.…”

Long-term spinal cord injury increases susceptibility to isometric contraction-induced muscle injury

“…Warren et al(1994) showed that just 15 tetanic isometric contractions after, but not before, hindlimb suspension in the soleus muscle of a mouse was sufficient to evoke force loss. Others have shown elevated plasma creatine kinase (CK) in human SCI patients after a single bout of functional electrical stimulation leg cycling (Robergs et al 1993). While plasma CK is not a direct marker of muscle injury, it has been repeatedly shown that elevated CK levels provide support that muscle fibers have been injured (Clarkson and Newham 1995;Clarkson et al 1992).…”

Health and Fitness Benefits of Functional Electrical Stimulation-Evoked Leg Exercise for Spinal Cord–Injured Individuals

“…58,59 FES cycling training was observed to increase protein expressions of glucose transporter GLUT-1 and GLUT-4 content in paralyzed muscles, 38,60 increased glycolytic and mitochondrial oxidative enzymes, 61 increased collagen turnover, 62 and increased endothelin and creatine kinase composition. 63 All these studies suggested that FESevoked cycling was highly effective for promoting muscle hypertrophy in individuals with thoracic SCI, particularly when external load was applied during such exercise. Positive changes were reported about the physical properties of muscles, such as their mass and volume, and also about altered muscle morphology and biochemistry.…”