Exposure of blood from patients with sickle cell disease to air changes the morphological, oxygen‐binding, and sickling properties of sickled erythrocytes

Abstract

We collected venous blood samples from 7 steady-state patients with homozygous sickle cell disease under venous oxygen pressure without exposure to air (UnExpblood) and compared the morphological, oxygen-binding, and sickling properties with those of SS cells in aliquots of the same venous blood samples that were oxygenated in room air or at a PO 2 near 180 mmHg (Exp-blood). Results showed that (1) upon deoxygenation under nitrogen, UnExp-blood generated a significantly higher percentage of elongated reversibly sickled cells (RSCs) than did Exp-blood; (2) upon gradual oxygenation of completely deoxygenated sickled cells, RSCs in UnExp-blood converted to discocytes at a higher oxygen pressure than did those in Exp-blood; (3) the degree of hysteresis between the sickling/desickling curves of UnExp-blood was greater than that of Exp-blood; and (4) deoxy-Hb S in hemolysate prepared from SS cells in UnExp-blood polymerized without a delay time, while those from Exp-blood polymerized with a distinct delay time. The in vivo properties of RSCs significantly changed upon oxygenation. We also found that the various properties of blood samples collected from patients with SCD by the ordinary method were similar to those of Expblood, probably because such blood samples are exposed to oxygen through air in the needle, syringe, and Vacutainer. Once SS cells were oxygenated, the in vivo properties of RSCs could not be recovered by partial deoxygenation to venous oxygen pressure.

β-Globin Sleeping Beauty Transposon Reduces Red Blood Cell Sickling in a Patient-Derived CD34+-Based In Vitro Model

“…In response to 5% O 2 - 95% N 2 we found that cells which were exposed to room air during culture did not show sickling or other gross morphological changes (data not shown). This was, in fact, consistent with previous reports [ 28 , 29 ].…”

“…While cells would sickle readily in response to metabisulfite, cells did not sickle in response to low oxygen tension alone. Similar results have been reported previously, including the observation that not all input RBCs will sickle in response to metabisulfite, and molecular results showed the presence of hemoglobin-S (HbS) as the major component of total Hb in cRBCs [ 28 , 29 ].…”

Perfluorocarbon emulsion improves oxygen transport of normal and sickle cell human blood in vitro

“…However, this is the first study to examine the O 2 transport of human SCD blood mixed with PFC emulsion at physiological temperature, blood pressure, and oxygenation/deoxygenation cycles. Repeated cycles may be of importance since such cycles induce progressive changes in cell shape and function (including O 2 binding) even without additional factors …”

“…Repeated cycles may be of importance since such cycles induce progressive changes in cell shape and function (including O 2 binding) even without additional factors. 33 The phenotypic diversity in SCD is widely recognized and there are large differences in clinical severity among patients. 34,35 The reasons for this broad spectrum of clinical manifestations are unclear and may involve factors directly related to O 2 transport, therefore pertinent to our study.…”

Sickle Cell Imaging Flow Cytometry Assay (SIFCA)

“…Sickling assays have been developed to give an objective measure of the percentage of circulating cells in a given blood sample that sickle upon exposure to conditions known to cause HbS shift to the T-state, which is prone to polymerize and cause RBC sickling. Traditionally, sickling assays rely on the subjective determination of the percentage of sickling cells by manually counting 200 RBCs through optical microscopy [3, 4, 5, 6]. Therefore, sickling assays based on optical microscopy are cumbersome, time-consuming, and highly observer dependent.…”