Pilot study of omega-3 fatty acid supplements in sickle cell disease.

In a previous retrospective study, it was observed that the greater the amounts of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the blood, the lesser the number of complications of sickle cell disease (SCD) and the higher the steady state haemoglobin level. SCD causes ischaemia-reperfusion injury and inflammation; which can be ameliorated by a metabolite of DHA that down-regulates expression of pro-inflammatory genes. The objectives of this prospective pilot study were to evaluate the effects of DHA and EPA supplements in SCD, and test the hypothesis that these effects are mediated partly by reducing inflammation. Oral DHA and EPA supplements were given to 16 SCD patients for 6 months. We then compared pre- and post-supplementation values of number of crisis, steady state Hb, plasma unconjugated bilirubin and three indices of inflammation: plasma interleukin-6, blood neutrophil and platelet counts. There was a significant reduction in the plasma level of unconjugated bilirubin, and the number of sickle cell crisis; but not in the markers of inflammation. The pilot data suggest that DHA and EPA supplements reduce the number of crisis and steady state haemolysis in SCD; but provide no evidence that these effects are mediated by reducing inflammation.

Patients with sickle cell disease have reduced blood antioxidant protection.

In previous studies, we found that homozygous sickle cell (HbSS) patients, compared with their healthy (HbAA) counterparts, had reduced levels of the omega-3 fatty acids, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, in red cells, platelets, and mononuclear cells. These differences were not due to lower intake of the two fatty acids. We have investigated whether reduced antioxidant status in the patients could help explain the observed phenomenon. Blood specimens previously obtained for fatty acid study from Nigerian (26 HbSS and 30 HbAA) and British (30 HbSS, 9 sickle cell-hemoglobin C/HbSC, and 15 HbAA) subjects were analyzed for antioxidant status. The Nigerian HbSS patients compared with the controls had lower plasma retinol, alpha-tocopherol, and beta-carotene concentrations (p < 0.005) and reduced activity of red cell Cu/Zn-superoxide dismutase (Cu/Zn-SOD) (p < 0.05). Similarly, the British HbSS group had reduced concentrations of plasma alpha-tocopherol (p < 0.005), and activities of red cell Cu/Zn-superoxide dismutase (p < 0.05) and Se-glutathione peroxidase (Se-GPx) (p < 0.005) than the controls. In addition, the British patients in comparison with those who had HbSC, a mild form of the disease, had lower alpha-tocopherol than that of the HbAA controls (p < 0.005). In the British sickle cell patients, there was a positive correlation between red cell ethanolamine phosphoglyceride (EPG) DHA and Cu/Zn-SOD activity (r = 0.700, p < 0.05), choline phosphoglyceride (CPG) DHA and Se-GPx activity (r = 0.605, p < 0.05), and CPG EPA and Se-GPx activity (r = 0.558, p > 0.05). Similarly, the percent DHA in red cell EPG was positively related with the activity of Se-GPx in the patients with HbSC (r = 0.674, p < 0.05). These findings suggest that the lower levels of membrane EPA and DHA in blood cells of the HbSS patients could be due to peroxidation resulting from a compromised antioxidant competence.

Abnormality of erythrocyte membrane n-3 long chain polyunsaturated fatty acids in sickle cell haemoglobin C (HbSC) disease is not as remarkable as in sickle cell anaemia (HbSS).

Sickle cell disease (SCD) is a group of inherited blood disorders in which clinical illness results from the presence of erythrocytes with sickled haemoglobin (HbS). Blood vessel occlusion is a fundamental pathological process in SCD. Sickle cell haemoglobin C (HbSC) disease and sickle cell anaemia (HbSS) share some pathophysiology and clinical manifestations. However, the former is generally less severe. Erythrocytes of HbSC patients have longer life span, reduced haemolysis, and lower propensity to adhere to vascular endothelium than those of their HbSS counterparts. The structure and function of erythrocytes are strongly modulated by membrane long chain polyunsaturated fatty acids (LCPUFA). We have tested the possibility that HbSC and HbSS patients have different membrane fatty acid composition consistent with the difference in their clinical severity. Steady-state patients, 9 HbSC and 28 HbSS, and 15 HbAA were studied. The HbSC patients had a higher level of linoleic (LA, P<0.05) and docosahexaenoic (DHA, P<0.05) acids, and lower arachidonic acid (AA, P<0.01) and AA/eicosapentaenoic acid (EPA) ratio (P<0.05) in erythrocyte choline phosphoglycerides (CPG) compared with the HbSS group. Similarly, the level of EPA was higher and AA/EPA ratio (P<0.01) lower in serine phosphoglycerides of the HbSC patients. In contrast to the HbSC, the HbSS group had lower levels of EPA (P<0.001), DHA (P<0.05), total n-3 metabolites and total n-3 fatty acids (P<0.001) in erythrocyte CPG compared with the healthy HbAA controls. Moreover, the HbSS patients with disease complications compared with those without complications had reduced DHA and total n-3 fatty acids (P<0.005) in erythrocyte CPG. The abnormalities in erythrocyte in LCPUFA which is manifested by an increase in AA and a decrease in EPA and DHA in HbSS relative to HbSC disease observed in this study are consistent with the contrast in clinical severity between the two entities.