A comparison of effects of oral thiocyanate and omega-3 fatty acid on serum level of soluble intercellular adhesive molecule one (sICAM-1), among steady state sickle cell patients

BACKGROUND: Binding of activated neutrophils to ICAM-1 receptors located on vascular endothelium, and circulating endothelial cells resulted in the obstruction of the vascular lumen of SCA people. This contributes to vaso-occlusion in a purely red cell disease. Hydroxylation of the ICAM-1 receptor on neutrophil detachment results in increased soluble ICAM-1 (sICAM-1) in plasma. Sickled red cells also attached to ICAM-1, producing more soluble products of ICAM-1 than the binding of normal red cells. Thiocyanate and omega-3 are known to reduce sickling of red blood cells and repair vascular activation, two parameters which increase soluble ICAM-1. The aim of this study was to assess, among steady state sickle cell patients, the comparative protective effect of oral thiocyanate over omega 3 fatty acid and routine drugs for sickle cell anemia. METHODS: Seventy-three HbSS patients aged 2-18 years were recruited into the observational case control study following informed consent. Consecutive recruitment was done when in vaso-occlusive crisis and sample taken for absolute neutrophil count (ANC) and hemoglobin genotype. They were followed-up for a minimum of 4 weeks till they were in steady state, when samples for repeat ANC and sICAM-1 were taken. Twenty of the HbSS participants were on oral thiocyanate and routine drugs, thirty were on omega 3 fatty acids + routine drugs and twenty were on routine drugs (folic acid, B-complex, and proguanil) only. Twenty-five sex and aged matched HbAA children were recruited as control with one off ANC and sICAM-1 measurement. Serum was analyzed with ICAM-1 ELISA kit (Biosensis Pty Ltd, Thebarton, Australia). Questionnaire and case note were used to determine the clinical efficacy of the use of all three interventions in those SCA >= 8 years. RESULT S: The sICAM-1 median values for the omega-3, thiocyanate, and routine drugs-only groups, respectively, were 837.25pg/mL (95% confidence interval 782-860), 895.43 pg/mL (790-980), 1027.68 pg/mL (902-1158); while that for the control group was 56.01(40-64.3) pg/mL. Significant difference was found between the sICAM-1 values for omega-3 and routine drugs groups, P<0.05, while no significant difference existed between the thiocyanate and routine drugs groups. All participants 8 years and older on thiocyanate and omega 3 had noticed both a reduction in intensity and frequency of vaso-occlusive pain. CONCLUSIONS: Significantly elevated sICAM-1 level among SCA patients shows that vascular activation exists and worsens with age. Significantly lower sICAM-1 levels noted on the omega-3 fatty acid group suggest efficacy in slowing vasculopathy. Clinically all medications were beneficial, regarding reducing frequency of vaso-occlusive crisis with no serious side effect noted during the study.