Decrease in erythrocyte glycophorin sialic acid content is associated with increased erythrocyte aggregation in human diabetes

Abstract

1. Sialic acid moieties of erythrocyte membrane glycoproteins are the principal determinants of the negative charge on the cell surface. The resultant electrostatic repulsion between the cells reduces erythrocyte aggregation and hence the low shear rate viscosity and yield stress of blood. 2. Using g.c.-m.s., a decrease in sialic acid content has been observed in the major erythrocyte membrane glycoprotein, glycophorin A, obtained from nine diabetic patients compared with that from seven normal control subjects [median (range): 3.30 (0.01-11.90) versus 18.60 (3.20-32.60) micrograms/100 micrograms of protein, P less than 0.02]. 3. Erythrocyte aggregation, measured by viscometry as the ratio of suspension viscosity to supernatant viscosity (LS/S) in fibrinogen solution, was increased in ten diabetic patients compared with ten normal control subjects (mean +/- SEM, 37.6 +/- 1.3 versus 33.8 +/- 0.6, P less than 0.02). 4. In the patients in whom both viscometry and carbohydrate analysis were performed, the decrease in erythrocyte glycophorin sialylation and the increase in erythrocyte aggregation in fibrinogen solution were related statistically (LS/S correlated negatively with glycophorin sialic acid content, r = 0.73, P less than 0.05). 5. Decreased glycophorin sialylation provides an explanation at the molecular level for increased erythrocyte aggregation and it may be important in the pathogenesis of vascular disease in diabetes.

Acidic and neutral sialidase in the erythrocyte membrane of type 2 diabetic patients

“…[1][2][3] However, while an increase in the sialic acid content of plasma has been consistently observed, [4][5][6] conflicting results have been obtained with regard to different tissues from diabetic patients: most investigators have observed a decrease, 1,7,8 while others have observed an increase 9 or no difference at all. 10 As to the erythrocyte membrane, where sialic acid plays an important role in the maintenance of red cell structure, permeability, integrity, viability, and survival in circulating blood [11][12][13] and where it is physiologically decreased during aging, the effect of the diabetic condition is yet unclear.…”

Alterations of red blood cell shape and sialic acid membrane content in septic patients

“…(Crit Care Med 2003; 31:2156 -2162) KEY WORDS: red blood cell; shape; deformability; sepsis; sialic acid; glycophorin; membrane charge; flow cytometry; oxygen supply importance of SA on RBC shape is demonstrated by the observation that neuraminidase-treated cells, which release their membrane SA content, undergo increased aggregation and display a reduced mean curvature (8). Decreases in RBC membrane SA content have been demonstrated in RBCs of patients with diabetes mellitus (9,10) and in senescent RBCs (11,12). The decrease in SA may explain the increase in RBC aggregability observed in diabetes mellitus (10), but the effects of SA on alterations of RBC shape remain controversial (8,13).…”

Selective gene transfer to tumor cells by recombinant Newcastle Disease Virus via a bispecific fusion protein

“…Crystal structure analysis confirmed that there is only one site on the HN protein with dual functions, the HA and NA activities (33). By possessing these activities, NDV can cause hemagglutination of red blood cells (35)(36)(37)(38)(39)(40). The addition of ·HN-IL-2 to NDV is shown here to prevent both HA and NA activities simultaneously.…”