Ethnic differences in erythrocyte membrane fluidity and the association with serum triacylglycerols

The objectives of this study were to determine whether there are difference s between black and white individuals with regard to the membrane fluidity of isolated erythrocytes, and/or in the relationships between membrane flui dity, gender and circulating lipids. Fluorescent polarization anisotropy. a s an index of membrane fluidity, was determined using the fluorescent probe 1 -(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) in 52 b lack and 52 white individuals, of whom 39 pairs were matched for age, sex a nd blood pressure. In the 39 matched pairs, the TMA-DPH anisotropy was sign ificantly higher in the black (0.262 +/- 0.007) compared with the white (0. 258 +/-0.005) subjects (P < 0.005). There was also a significant difference in serum lipids. Gender differences in TMA-DPH anisotropy were observed in the white but not in the black individuals. The associations between membr ane fluidity and serum lipids were examined in the total group, separated a ccording to ethnic group. Although the associations were in the same direct ion in both groups, the association was only significant in the white subje cts (r = -0.42; P <0.02). The ethnic difference in membrane fluidity was ab olished when adjusting for serum triacylglycerols. In conclusion. ethnic di fferences in erythrocyte membrane fluidity, as determined by the use of TMA -DPH anisotropy, appear to be the result of ethnic differences in the level of serum triacylglycerols.