Abnormalities of Aggregation, Thromboxane A2 Synthesis, and 14C Serotonin Release in Platelets of Patients with Idiopathic Scoliosis

Platelet functions were investigated in 16 patients with idiopathic scoliosis (IS), in seven patients with congenital scoliosis (CS), and in 12 healthy individuals who served as a control group. All were females, aged 11 to 22 years. Platelet aggregation anomalies were observed in all IS patients. These constituted an impaired platelet-release reaction when aggregation was induced with ADP or epinephrine, but not with collagen or arachidonic acid. A decreased thromboxane A2 synthesis and impaired 14C-serotonin release were also observed when platelets were stimulated with ADP or epinephrine. Platelet from CS patients and the controls did not show any functional abnormalities when stimulated with the above four aggregating agents. The platelet function anomaly in IS patients was not associated with prolongation of the bleeding time, spontaneous occurrence of hemorrhagic episodes, or increased bleeding during invasive procedures, including major spinal surgery. The above findings and the recently described platelet structural anomalies in IS may imply that the pathological process operative in idiopathic scoliosis involves not only the axial skeleton, but also cellular blood elements. The similarity between blood platelets and muscle cells, and the anomalies that have been found in both systems in IS, support the notion that a muscle disorder may be involved in the pathogenesis of the disease.