ERYTHROCYTE RHEOLOGICAL CHANGES IN OBESE PATIENTS - INFLUENCE OF HYPERINSULINISM

OBJECTIVE: To investigate the rheological properties of RBC in obese s ubjects and the factors associated with their changes. SUBJECTS: Two c onsecutive studies of non diabetic obese subjects. MEASUREMENTS: Filtr ation index of RBC using the Hanss hemorheometer, RBC filterability us ing a cell transit time analyser and RBC aggregation measured on the M yrenne aggregometer. RESULTS: In both studies an increase in the filtr ation index of RBC, namely a reduction in their deformability, was fou nd. In the first study the filtration index correlated negatively with hematocrit and positively with plasma C peptide levels. In the second study RBC filterability was also studied by the cell transit time ana lyzer in which there is no aggregate formation. The RBC transit time w as not found to be different in the obese patients and in the controls , but RBC aggregation was increased and correlated significantly with body weight and BMI. RBC aggregation worsened after four days of hypoc aloric diet. CONCLUSION: (1) obesity, independently of the other cardi ovascular risk factors, is associated with significant changes in RBC rheology; (2) these changes are probably related for the most part to plasma factors, possibly via hyperinsulinemia, even if changes in the chemical composition of the RBC membrane are not excluded, (3) RBC agg regation worsens during the first days of a hypocaloric diet; (4) rheo logical changes in RBC seem to be another component of the insulin res istance syndrome.