Plasma zinc levels inversely correlate with vascular cell adhesion molecule-1 concentration in children with sickle cell disease

Abstract

Zinc deficiency has been implicated in impaired cell-mediated immunity of children with sickle cell disease (SCD). However, its influence on the expression of vascular cell-adhesion molecule-1 (VCAM-1) on endothelial cells, a protein involved in vasoocclusion, has not been previously investigated. We therefore measured (soluble) sVCAM-1 and zinc in 76 SCD children and 96 non-SCD children, mean age 7.73 years and 11.24 years, respectively. Although mean zinc levels of both groups were within the normal range (approximately 14.5 micromol/l), 14.5 % of SCD and 11% of non-SCD children (without inflammation) had levels below normal (10.7 micromol/L). Mean sVCAM-1 concentrations of SCD children (837 microg/l) were significantly higher than those of controls (627 microg/l) (p < 0.001). Differences persisted after taking into account age, hemoglobin phenotype, and inflammation (alpha-l acid glycoprotein >l g/l and C-reactive protein >10 mg/I). sVCAM-1 negatively correlated with serum (r = -0.444) and red blood cells zinc (r = -0.242, p < 0.05) but not with acute-phase proteins. Mean sVCAM-1 tended to be higher in SCD children with than in those without a history of a health problem (infection, pain crisis or were transfused; not significant). Data suggest that zinc may modulate the clinical status of SCD children through VCAM-1 expression, and zinc supplementation may be beneficial in these patients.