The effect of phorbol esters on human erythrocyte morphological discocyte-echinocyte transitions

Hypoxic storage of erythrocytes slows down storage lesions and prolongs shelf-life

Conventional storage conditions of erythrocytes cause storage lesions. We propose that hypoxic storage conditions, involving removal of oxygen and replacement with helium, the changes in stored erythrocytes under hypoxic condition were observed and assessed. Erythrocytes were divided into two equal parts, then stored in conventional and hypoxic conditions, separately. Blood gas analysis, hemorheology, and hemolysis were performed once a week. Energy metabolism and membrane damage were monitored by enzyme-linked immunosorbent assay. Phosphatidylserine exposure was measured by flow cytometry. P₅₀ was measured and the oxygen dissociation curve (ODC) plotted accordingly. Erythrocyte morphology was observed microscopically. In the 9th week of storage, the hemolysis of the hypoxia group was 0.7%; lower (p < .05) than that of the control group and still below the threshold of quality requirements. The dissolved oxygen and pO₂ were only 1/4 of that in the control group (p < .01); the adenosine triphosphate, glucose, and lactic acid levels were decreased (p < .05), while the 2,3-diphosphoglycerate levels were increased relative to that in the control group (p < .01). There were no statistically significant differences in membrane damage, deformability, and aggregation between the two groups. In addition, the ODC of the two groups was shifted to the left but this difference was not statistically different. Basically similar to the effect of completely anaerobic conditions. Erythrocytes stored under hypoxic conditions could maintain a relatively stable state with a significant decrease in hemolysis, reduction of storage lesions, and an increase in shelf-life.

Hyperspectral enhanced dark field microscopy for imaging blood cells

In this work, a novel methodology based on hyperspectral imagery with enhanced Darkfield microscopy for probing and characterizing changes in blood cell components was tested. Two main categories of blood cells were analyzed, red and white blood cells. Unique spectral signatures of ordinary and most common deformed morphologies of red blood cells were identified. Moreover, examination of white blood cells allowed to characterize and differentiate active from inactive cells. The findings indicate the ability of this technique to detect changes in light scattering property of blood cells due to their morphological properties Since pathological states can alterate the discocyte shape, this preliminary, but promising application of the hyperspectral analysis to blood cells can be useful to evaluate significant correlations of blood cell spectral features in healthy and pathological conditions. The combination of the quali- and quantitative spectral signatures of hyperspectral imaging microscopy with the information of the subject health conditions may provide a new tool for clinical applications.

Regulation of the glycophorin C-protein 4.1 membrane-to-skeleton bridge and evaluation of its contribution to erythrocyte membrane stability

The band 3-ankyrin-spectrin bridge and the glycophorin C-protein 4.1-spectrin/actin bridge constitute the two major tethers between the erythrocyte membrane and its spectrin skeleton. Although a structural requirement for the band 3-ankyrin bridge is well established, the contribution of the glycophorin C-protein 4.1 bridge to red cell function remains to be defined. In order to explore this latter bridge further, we have identified and/or characterized five stimuli that sever the linkage in intact erythrocytes and have examined the impact of this rupture on membrane mechanical properties. We report here that elevation of cytosolic 2,3-bisphosphoglycerate, an increase in intracellular Ca(2+), removal of cell O(2), a decrease in intracellular pH, and activation of erythrocyte protein kinase C all promote dissociation of protein 4.1 from glycophorin C, leading to reduced retention of glycophorin C in detergent-extracted spectrin/actin skeletons. Significantly, where mechanical studies could be performed, we also observe that rupture of the membrane-to-skeleton bridge has little or no impact on the mechanical properties of the cell, as assayed by ektacytometry and nickel mesh filtration. We, therefore, suggest that, although regulation of the glycophorin C-protein 4.1-spectrin/actin bridge likely occurs physiologically, the role of the tether and the associated regulatory changes remain to be established.

Alterations in echinocyte transformation and erythrocyte sedimentation rate during hemodialysis

In 18 uremic patients under regular hemodialysis (HD) with bicarbonate dialysate, the echinocytes and erythrocyte sedimentation rates (ESR) were determined in 4 blood samples collected from the arterial line at 0, 45, 120, and 240 min (end-HD) in one HD session by a bioincompatible dialyzer and in another by a biocompatible one. In the HD session by a bioincompatible dialyzer, the mean values (+/- SEM) of echinocytes (%) at 0, 45, 120, and 240 min were 8.89 +/- 1.15, 20.77 +/- 2.35, 7.39 +/- 1.1, 5.27 +/- 0.66 and of ESR (mm/h) were 65.00 +/- 6.26, 47.05 +/- 3.89, 66.72 +/- 6.00, 68.44 +/- 5.92, respectively. According to these findings, echinocytes show a transient significant increase at 45 min HD in comparison to those at 0 (p < 0.001), 120 (p < 0.001), and 240 (p < 0.001) min while ESR shows a transient significant decrease at 45 min HD compared with the rates at 0 (p < 0.05), 120 (p < 0.05) and 240 (p < 0.01) min. In the HD sessions with the biocompatible dialyzer, the mean values (+/- SEM) of echinocytes at the aforementioned 4 time points were 8.55 +/- 1.10, 17.05 +/- 2.40, 17.05 +/- 1.19, and 5.11 +/- 0.75%, and the ESR values were 60.89 +/- 6.08, 44.33 +/- 4.18, 62.94 +/- 6.55, and 65.61 +/- 6.13 mm/h, respectively. These values also show a transient significant increase of echinocytes at 45 min HD in comparison with those at 0 (p < 0.01), 120 (p < 0.01), and 240 (p < 0.001) min, with a parallel transient decrease of ESR at 45 min HD as compared to the ones at 0 (p < 0.05), 120 (p < 0.05), and 240 (p < 0.05) min. Although the echinocytosis at 45 min HD was more prominent in HD by the bioincompatible than by the biocompatible dialyzer, the comparison between these values indicates no significant difference in the echinocytes or the ESR. In conclusion, uremic patients receiving HD exhibit echinocytes, the percentage of which shows a transient increase at 45 min HD that returns to about baseline at 120 min HD. In parallel with the changes in echinocytes, the ESR shows an inverse change at 45 min HD which returns to baseline at 120 min HD.