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Human red cell hemolysis rates in the subsecond to seconds range. An analysis
Biophysical Journal
|November 1, 1977
Summary
Human red blood cells undergo rapid hemolysis under hypoosmotic shock. Cell rupture and leaking kinetics reveal complex processes, not simple "all or none" events, influenced by swelling rates and cell age.
Area of Science:
- Biophysics
- Cell Biology
- Hematology
Background:
- Human red blood cells (erythrocytes) are crucial for oxygen transport.
- Understanding red blood cell lysis (hemolysis) is vital for transfusion medicine and disease diagnostics.
- Previous models of hemolysis often assumed simpler kinetics under less extreme conditions.
Purpose of the Study:
- To investigate the kinetics of hypoosmotic shock in normal human red blood cells at 25 degrees C.
- To compare experimental hemolysis data with existing theoretical models.
- To elucidate the factors controlling the rate and mechanism of red blood cell rupture.
Main Methods:
- Utilized a rapid kinetics apparatus with a resolving time of approximately 50 milliseconds.
- Subjected normal human red blood cells to hypoosmotic shock, including mixing with pure water.
- Analyzed hemolysis plots to determine kinetic parameters and compare with models.
Main Results:
- Fast hemolysis plots under severe hypoosmotic shock were not symmetric sigmoids and did not fit an "all or none" model.
- The onset of hemolysis velocity depended on the cell swelling rate (lag phase) under extreme conditions.
- Mean time to rupture and leaking was approximately 0.6 seconds, with osmotically driven solvent flow being a key factor in discocyte-to-sphere transformation.
- Hemolysis followed two rate processes influenced by a distribution of cell fragilities, likely related to cell age.
- At low salt concentrations (≤ 0.05 M), electrostatic effects may contribute to rupture, in addition to hypotonicity and hypoosmolality.
Conclusions:
- Red blood cell hemolysis under severe hypoosmotic shock is a complex process involving multiple rate-limiting steps and cell-to-cell variability.
- The rate of water influx and cell swelling are primary drivers of the discocyte-to-sphere transition and subsequent rupture.
- Cell age and surface charge (at very low salt concentrations) can influence red blood cell fragility and lysis dynamics.