Monitoring of erythrocyte aggregate morphology under flow by computerized image analysis

Area of Science:

• Biophysics
• Hematology
• Rheology

Background:

• Red blood cell (RBC) aggregation influences blood flow properties.
• Understanding RBC aggregate morphology is crucial for diagnosing various hematological conditions.

Purpose of the Study:

• To investigate and quantify the morphology of red blood cell aggregates under varying conditions.
• To characterize the influence of different aggregating agents (dextrans) on RBC aggregate shape.
• To explore the relationship between aggregate size, shape, and applied shear stress.

Main Methods:

• Direct visualization of RBC aggregation using a computerized image analyzer.
• Quantification of aggregate morphology using an Aggregate Shape Parameter (ASP).
• Aggregation induced by dextran-70 and dextran-500, compared to plasma, under varying shear stress.

Main Results:

• RBC aggregate morphology is agent-dependent: dextran-500 and plasma yield rouleau aggregates, while dextran-70 produces clusters.
• The ASP decreases with increasing aggregate size, indicating a lengthening effect.
• Aggregate shape distributions remain consistent despite changes in dextran concentration or shear stress.
• Shear stress application causes stretching of rouleau aggregates, reflected in ASP changes.

Conclusions:

• The Aggregate Shape Parameter (ASP) serves as a characteristic measure of RBC intercellular interactions.
• A theoretical model is proposed to evaluate deviations from rouleau aggregate structure.
• Findings contribute to a deeper understanding of RBC aggregation dynamics and their implications in blood rheology.