Echinocyte-stomatocyte transformation and shape control of human red blood cells: morphological aspects

Shape changes in caprine erythrocytes exposed to chlorpromazine and lysolecithin

Stomatocytic and echinocytic transformations of caprine erythrocytes were studied in vitro using chlorpromazine as a stomatocyyic agent and lysolecithin as an echinocytic agent. Morphologic changes in erythrocytes generally varied with the cell shape and the concentration of the substances used. Discoytic, triangular, and pear-shaped red cells common to normal goats, exhibited classical stomatocytic and echinocytic changes with formation of spherostomatocytes, sphero-echinocytes, and spherocytes. In comparison, fusiform and spindle-shaped red cells found in certain Angora goats seemed less prone to shape changes and required greater concentrations of the inducing agents to effect such changes. Chlorpromazine at higher concentrations also inflicted localized membrane damage in form of tiny pits and lysolecithin likewise induced formation of fragile smooth or beaded filaments.

Red blood cell morphology after a 100-km run

We studied the red blood cells of male athletes competing in a 100-km run. The RBC, haematocrit, and red cell indices were unaffected. The red cell morphology was studied in a wet preparation with light microscopy. A slight stomatocytosis was observed after the run compared to a control day (12.4 +/- 1.8% vs 4.3 +/- 1.8%, P less than 0.05). This difference persisted when runner red cells were incubated in buffer. Red cells from a normal donor did not undergo stomatocytic transformation when incubated in runner plasma. These data indicate that stomatocytosis after long-distance running is not caused by a plasmatic factor but is a change in the red cell membrane itself.

Time-related shape control modifications during erythrocyte storage with additive solutions

To obtain more detailed information on the reversibility of shape alterations in blood bank stored erythrocytes, we have studied shape recovery after chemical crenation and rheological properties in 8 PAGGS-sorbitol preserved erythrocyte concentrates during a five week storage period under blood bank conditions. Our results show that red cell capability to regain a normal discoid shape after chemical crenation decreases during storage but is not lost over a five week period. Moreover there is a significant but weak correlation between red cell ATP content and both shape recovery capability and viscosity. Our results confirm suspicious that red cell shape perturbations following blood bank storage are widely reversible. Two different mechanisms may be involved in reducing shape recovery capability during storage, namely an ATP-dependent mechanism and an energy-independent one. The energy dependent mechanism may be preserved by the previous addition of solutions which maintain higher energy levels during storage.

Increased proteolytic activity of erythrocyte membrane in spur cell anaemia

In a case of 'spur cell anaemia' (SCA) a reduced esterified/free cholesterol ratio was found in plasma, in LDL and HDL fractions and an increased cholesterol/phospholipid (C/PL) molar ratio in erythrocyte membrane. Cation transport was normal with the exception of Li-Na counter-transport was decreased. An increased intrinsic membrane proteolytic activity (IMPA) was demonstrated by the generalized reduction or, sometimes, disappearance of protein bands on SDS-PAGE in patient ghosts when the proteolysis was allowed. This characteristic was found to be transferable to normal cells by incubation in SCA-plasma; moreover membrane C/PL molar ratio was augmented after incubation. Normal plasma was not able to normalize IMPA of SCA cells 'in vitro', even if it induced a remarkable decrease of membrane C/PL molar ratio. Nevertheless IMPA normalization did occur 'in vivo', when the SCA cells were exposed to therapeutic 'plasma exchange' (3.3 litre/week). The results suggest the following conclusions: (a) in our SCA patient there is an increased IMPA; (b) this feature, as well as membrane lipid alteration, is transferable to normal erythrocytes; (c) this case seems to demonstrate, for the first time in our knowledge, a modulating effect of plasma on IMPA in erythrocytes.

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

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.

Storage of human red blood cells and platelets. Some aspects concerning the factors leading to storage lesion characterized as morphological changes and vesiculation. Minireview based on a doctoral thesis

1. Storage renders erythrocytes more responsive to thermally induced morphological changes, especially the shedding of microvesicles. 4-8 week old cells can be morphologically "rejuvenated" by heating. 2. If pH increases during storage of platelets an extensive loss of small particles occurs. The platelet disintegration is associated with a loss in the metabolic activity, discharge of LDH, increased susceptibility to phospholipid hydrolysis by phospholipase C and is found to be initiated during the actual preparation of platelet concentrates. 3. Activation of platelets during preparation can be decreased by shortening the first centrifugation time or by using adenine in the anticoagulant. 4. A 4 hour prestorage of the whole blood unit prior to centrifugation strongly decreases the activation of platelets upon stimuli and results in platelet concentrates much more stable to storage.