40 M . Sancheti et al .: J Extra Corpor Technol 2024 , 56 , 37 – 44
Figure 3 . Measurements of biomarkers of platelet activation in Trillium Ò Biosurface circuit . ( A ) Soluble P-selectin levels reduced at 30 min and 55 min , with values at each time point falling within ± 2 SD of the mean . All measurements are presented as normalized values over the platelet count for each time points . ( B ) The normalized values for GPIIb / IIIa levels in circulated bovine blood show a significant decrease at 55 min , with all measured values falling within ± 2 SD of the mean . ( C ) Normalized values for PF4 and ( D ) b-TG did not show any significant changes at 5 min , 30 min , and 55 min , but all values fell within ± 2 SD of the mean , indicating minimal intra-variability across technical replicates . ( Mean ± SD , P < 0.05 , five technical replicates ). GPIIb / IIIa : Glycoprotein IIb / IIIa ; PF4 : Platelet Factor 4 ; b-TG : b-Thromboglobulin .
Measurements of biomarkers of platelet activation in Trillium Ò Biosurface circuit
ELISA assay was used to measure the levels of platelet activation markers ( soluble P-selectin , PF4 , GPIIb / IIIa , and b-TG ) in circulated bovine blood at 5- , 30- , and 55-minutes during circulation using Trillium Ò Biosurface coated tubes . The values for biomarkers at 5 min were arbitrarily set as the baseline measurement for each biomarker within the same circuit type . Measurements at 30 min and 55 min were then compared to measured values at 5 min to assess potential time-dependent changes in biomarkers at each collection time point . All the biomarker concentrations were normalized over the platelet counts for that time point . The results indicate that in the Trillium Ò Biosurface circuit , the values for platelet activation biomarkers fall within ± 2 SD of the mean for soluble P-selectin , GPIIb / IIIa , PF4 , and b-TG ( Fig . 3 ). The normalized values for soluble P- selectin dropped at 30 min and 55 min ( Fig . 3A ), with GPIIb / IIIalevelsshowingasignificant drop only at 55 min
( Fig . 3B ) as compared to basal levels recorded at 5 min . On the other hand , the values for PF4 and b-TG did not show any significant changes with time ( Figs . 3C and 3D ). The data indicates that the luminal surface of Trillium Ò Biosurface circuits has no effects on the secretion levels of these two biomarkers in circulated blood . We also ran statistical analyses using the recorded raw values for all four biomarkers secretion and translocation levels without normalization over the platelet counts in bypassed bovine blood at 5- , 30- , and 55-minutes in Trillium Ò Biosurface circuit ( Supplementary Fig . S1 ). Measurements of biomarkers of platelet activation in Xcoating TM Circuit
The same blood collection methods and time points were used to evaluate the secretion and translocation levels of four platelet activation biomarkers using the Xcoating TM bypass circuit . Our results show that normalized values ( over platelet