Comparative sensitivity of human fetal and adult erythrocytes to hemolysisby pulsed 1 MHz ultrasound

Human fetal and adult erythrocytes differ significantly in mean corpuscular volume (MCV), the fetal cells being larger than adult cells and diminishin g in MCV as gestational age (GA) increases, Previous studies have shown tha t the sensitivity of erythrocytes from different species to lysis by mechan ically applied shear stress increases as MCV increases. The tested hypothes es in the present project were: 1. fetal erythrocytes would be more sensiti ve to sonolysis than adult erythrocytes because of the former's larger size , and 2. erythrocyte sonolytic sensitivity would scale with MCV. Fetal and adult erythrocytes were resuspended to 40% hematocrit in oxygenated isotoni c saline solution and 500 muL aliquots were exposed for 60 s to 200 mus bur sts of 1-MHz ultrasound (US) (peak pressures: similar to4.8 MPa positive, s imilar to2.7 MPa negative; duty factor = 0.01), either with or without 3.6 volume % Albunex (R) (ALS) present, Background-corrected hemolysis was indi stinguishable from zero in sham-er;posed fetal or adult erythrocyte suspens ions, Without ALX, mean background-corrected US-induced hemolysis was signi ficantly greater than zero for fetal and adult cells (0.42 +/- 0.15% vs. 0. 62 +/- 0.15%), but fetal cell lysis was not significantly greater than adul t cell lysis, With ALX, US-induced hemolytic yields increased similar to 80 -fold (fetal: 50.53 +/- 2.14%; adult: 46.40 +/- 1.85%), and were significan tly higher for fetal than for adult cells. There was also a statistically s ignificant correlation between MCV and US-induced background-corrected hemo lysis, Thus, the two hypotheses were supported. (C) World Federation for Ul trasound in Medicine & Biology.