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

Abstract

The behavior of the 2 sialidase forms present in the erythrocyte membrane was investigated in 117 subjects with type 2 diabetes mellitus versus 95 healthy controls. A significant increase of the acidic form of sialidase, which is anchored to the membrane by a glycosylphosphatidylinositol bridge, was observed in erythrocyte resealed membranes. On the contrary, the neutral form of the enzyme, the only one capable of removing lipid-and protein-bound sialic acid from endogenous and exogenous sialoderivatives, was significantly reduced with a consequent increase of erythrocyte membrane total sialic acid content. Disease duration, therapy, glycemia, parameters of metabolic control, and presence of complications, except nephropathies, had no influence on the tested enzyme activities. Diabetic subjects showed a different erythrocyte age distribution, with an almost double proportion of young red cells and only one quarter of senescent ones compared with controls. In young erythrocytes, diabetic and control subjects had the same distribution of the 2 enzymes, while in senescent cells the acidic enzyme was increased 3.5-fold and the neutral form was reduced by half in the diabetic subjects. The increase of both acidic sialidase and total membranebound sialic acid, together with an overpresence of young red cells in diabetics, suggests that in this pathological condition there might be an altered aging process with a diminished expression of the neutral form of the enzyme and an increase of bound sialic acid. It has been suggested that the expression of the neutral enzyme requires some activation mechanism that is impaired in diabetes.

Overexpression of Plasma Membrane-associated Sialidase Attenuates Insulin Signaling in Transgenic Mice

“…However, this is not likely to be directly connected to the present results, because the substrate is targeted by lysosomal type sialidase, which could account for the observed activity. A recent report (36) describing increased membrane sialidase activity in erythrocytes of diabetic patients indicates that our findings are probably applicable to human diabetes. We are actually having possible evidence of polymorphism of the NEU3 gene in diabetic patients, 2 and we are now analyzing how the genetic variation is associated with the clinical features of diabetic patients.…”

Haptoglobin 2-2 Phenotype is a Risk Factor for Type 2 Diabetes in Ghana

“…Free hemoglobin promotes damage to LDL within the blood vessel through the Fenton reaction 23,33) , leading to the early stages of endothelial dysfunction characteristic of type 2 diabetes. The situation is aggravated as the diabetes progresses and the turnover of blood cells is increased, making hemoglobin available for glycosylation 34) . Glycosylated hemoglobin (GlycHb) is even more difficult for CD163 to scavenge, reducing the antioxidative function of the complex further 31) .…”

Effect of Low and High Dose Sugammadex on Erythrocyte Deformability in Streptozotocin-Induced Diabetic Rats

“…Erythrocytes with a rigid membran structure can be easily distorted in microcirculation. Consequently, reticulocyte counts increase two fold and old erythrocyte counts decrease in 1/4 (22). Another negative effect of high glucose levels is glycosylation of skeletal proteins such as beta spectrin, ankyrin and protein 4.1.…”