Red cell vacuoles: Their size and distribution under normal conditions and after splenectomy

Abstract

The frequency of occurrence of vacuoles in red blood cells was studied by transmission electron microscopy. Small vacuoles were found in about 13% of the cell sections, and they had a mean diameter of 130 +/- 72 nm (mean +/- SD). It can be estimated that there were about 20 small vacuoles per erythrocyte. The frequency of vacuoles was similar in density-separated cell fractions. In splenectomized patients, the small vacuoles were 4 times more frequent; there was again no difference in vacuole density between top and bottom fractions of density-separated red blood cells. The bottom fraction of red blood cells from splenectomized patients, however, had a high incidence of large vacuoles (greater than 300 nm in diameter) and clustering of small vacuoles. These large vacuoles were probably the result of aggregation and fusion of small vacuoles, and their size allowed detection by light microscopy. Hence, the well-known "pocked" or "pitted" red blood cells of splenectomized individuals were more frequent in the bottom fraction. We conclude that small vacuoles occur normally in erythrocytes, that they tend to cluster and fuse during cell aging, and that the spleen is capable of removing these structures when they reach a certain size.

Intravascular Hemolysis, Vascular Endothelial Cell Activation and Thrombophilia in Splenectomized Patients with Hemoglobin E/β-Thalassemia Disease

“…The worsened IVH could be due to a not-as-efficient function of non-splenic mononuclear phagocytes in the ridding of defective or aged RBCs, in keeping with a previous report of RBCs with more vacuoles, particularly large ones, after splenectomy [28]. …”

Erythrocyte vesiculation: a self‐protective mechanism?

“…The erythrocytederived vesicles isolated from the plasma of freshly drawn blood contained all haemoglobin components in a pattern similar to that of old erythrocytes, in accordance with the increased haemoglobin loss in the second half of the erythrocyte lifespan (Willekens et al, 2003). Vesicles were also observed in erythrocytes of all ages and were shown to accumulate after splenectomy (Reinhart & Chien, 1988). In asplenia, vesicles or vacuoles that are larger than 300 nm can be observed as 'pits' in the smear.…”

Hemoglobin loss from erythrocytes in vivo results from spleen-facilitated vesiculation

“…6 In asplenia, not only a 4-fold increase in the number of these small vesicles can be found, but also abnormally big vacuoles (diameter Ͼ 300 nm) in about 30% of RBCs, some of which are known to contain hemoglobin. 6 A previous study indicated a positive relationship between the number of RBCs with big vacuoles ("pitted" cells, as seen with phase-contrast microscopy) and the HbA 1 percentage in RBC populations fractionated according to density. 7 Also, in this study the HbA 1 percentage of whole blood was increased.…”

“…Some of these vacuoles are known to contain hemoglobin. 6 A previous study indicated a positive relation between the number of RBCs with big vacuoles ("pitted" cells), and the HbA 1 percentage in RBC populations fractionated according to density. 7 Likewise, the HbA 1 percentage in whole blood was higher in asplenic individuals.…”