Thermodynamic evaluation of vesicles shed by erythrocytes at elevated temperatures

Erythrocytes undergo structural transformation and shed small vesicles at elevated temperatures. To characterize mechanisms of the phenomenon, the Arrhenius and Eyring equations were used for analysis of the literature, experimental data on vesiculation of human and rat erythrocytes after the temperature was elevated by physical exercise or by exposure to external heat. The thermodynamic analysis of the data showed that erythrocyte transformation, vesicle release, and other associated processes are driven by entropy with enthalpy-entropy compensation. It is suggested that the physical state of the hydrated cell membrane is responsible for the compensation. The increase of vesicle number related to elevated temperatures may be indicative of the heat stress level and serve as diagnostic of erythrocyte stability and human performance.