Abnormal Erythrocyte Rheology in Patients with Morbid Obesity

Abstract

The objectives of this study were to investigate the rheological properties of the erythrocyte in patients with morbid obesity and to follow them up after a short-term weight loss. A fluorescent polarization method was used to assess erythrocyte membrane biorheology and to measure its fluidity. Eighteen sub jects participated in the study: 8 healthy controls and 10 patients with morbid obesity.The erythrocyte membrane fluidity was obtained in the healthy subjects and in the patients with morbid obesity prior to and after a ten-day zero-calorie diet. Fluidity was determined by steady-state fluorescence polarization after incorpo ration of the lipophilic probe 1,6-diphenyl-1,3,5 hexatriene (DPH). With this method, the anisotropy parameter at 37 ° C, which is inversely related to mem brane fluidity, was obtained.The patients with morbid obesity revealed an abnormal erythrocyte rheol ogy. They exhibited an abnormally low erythrocyte membrane fluidity as com pared with normal subjects. The anisotropy parameter at 37°C was 1.417 ± 0.093 in these obese patients compared with 1.279 ± 0.043 in normal- weight controls (p < 0.01).Upon a short-term significant weight loss from a body mass index (BMI) (weight/height2) of 39 ± 5 to 36 ± 5 kg/m2 (p < 0.05), the anisotropy parameter did not change (1.401 ±0.190).Thus, fluidity measurements permit recognition of an abnormal erythrocyte rheology in patients with morbid obesity. This abnormality may partially ex plain the excess cardiovascular and thromboembolic morbidity in morbid obe sity.