Effect of strenuous arm exercise on oxidized-LDL-potentiated platelet activation in individuals with spinal cord injury

This study investigates how strenuous arm exercise affects oxidized-low den sity lipoprotein (Ox-LDL) mediated-platelet activation in patients with SCI . Ten patients with SCI and ten age- and sex-matched healthy subjects exerc ised strenuously using an arm crank ergometer. The following measurements w ere taken both when the subjects were at rest, and immediately after exerci se: plasma lipid profile. Ox-LDL mediated platelet aggregability and [Ca2+] (i), urinary 11-dehydro-thromboxane B-2 (11-dehydro-TXB2) and 8-iso-prostag landin F-2 alpha (8-iso-PG F-2 alpha) contents, and plasma NO metabolite (n itrite plus nitrate) level. Based on these measurements, the major findings of this study can be summarized as follows: 1) the SCI group had higher ur inary 8-iso-PGF(2o) and 11-dehydro-TXB2 contents, but a lower plasma nitrit e plus nitrate level than the control group: 2) at rest, the SCI group had a higher platelet aggregability and [Ca2+](i), and Ox-LDL-potentiated plate let activation than the control group; 3) Ox-LDL-potentiated plate let acti vation was enhanced by strenuous arm exercise in both groups, but the effec t of exercise was more pronounced in the SCI group than In the control grou p; 3) treating the platelet with L-arginine inhibited Ox-LDL-potentiated pl atelet activation in both groups. The study concludes that individuals with SCI had more extensive resting and exercise-enhanced Ox-LDL-potentiated pl atelet activation and greater amounts of preformed lipid peroxides than tho se without SCI. Therefore. supplementation therapy with antioxidants may be needed for patients with SCI. especially in a strenuous arm exercise perio d.