Sickle cell disease and folate supplementation

Abstract

Sickle Cell Disease is an important inherited blood disorder in which anemia occurs due to short life span of the deformed RBCs. Though SCD is predominantly present in Africa, it has been reported from other tropical regions including India. SCD may also manifest as vaso-occlusive crisis which occurs as a result of interplay among impaired blood rheology, increased adhesiveness of RBCs with inflammatory cells and vascular endothelium, and hemostatic activation. Damage of erythrocyte membranes also increases exposure of adhesion molecules and binding motifs viz. phosphatidyl serine, basal cell adhesion molecule-1/Lutheran, integrin-associated protein, and intercellular-adhesion-molecule-4. Release of immature RBCs or reticulocytes with adhesion molecules and increased cellular effect of selectins P- and E-, vascular-cell-adhesion-molecule-1, ICAM-1 and interleukin-8 on endothelial cells aggravates the crisis. Increased level of circulating homocysteine causes increased cytotoxic activity on endothelial cells, elevates hydrogen peroxide levels, decreases nitric oxide synthesis, induces cytokine production to stimulate the inflammatory state, activates procoagulant factors, and dysregulation of lipid metabolism. Positive role of folic acid supplementation in SCD is not well supported and there are possible side effects of folate supplementation. The final biologically active form of folic acid, L-Methylfolate or Levomefolic acid or 5-MTHF, is the best option which gets readily absorbed and exerts its action without requiring any bioconversion. Keywords: Sickle cell disease, Vaso-occlusive crisis, 5-MTHFR, Folate supplementation.