The Negative Effects Of Stored RBC On Cardiac Surgery Patients And Its Mechanism Research

ObjectiveA retrospective nested case-control study was used to find the association betweenstored RBC and postoperative outcomes of on-pump CABG patients, and on that basiswe analyzed effects of stored RBC supernatant on myocardial cells from the cell,subcellular and metabonomics levels respectively in order to provide experimental basisof further clear the RBC function changes during storage, avoid the side effects ofstored RBC transfusion, and improve the clinical effects of RBC transfusion.Methods1. We defined the in-hospital serious common complications as the ones occurringafter the operation, as the primary endpoint “severe outcome”, and the221on-pumpCABG patients were divided into the case and control according to the “severeoutcome” they have or not. A nested1:3case-control analysis matched on gender,age and cardiopulmonary bypass time at baseline was used to address the researchissue. The association of mean RBC storage time with the “severe outcome” wasassessed using conditional multiple logistic regression analysis.2. Suspended red blood cells were made from six qualified donors’2U whole blood,after centrifugal, supernatant were collected at the storage time of0,7,14,21,28and35days. RBC supernatant of different storage time were co-culture with SD ratmyocardial cells, and the myocardial cell pulsation were observed at0.5,3,6and24hours.3. We simulated the K+concentration of the old RBC supernatant and to explore itseffect on the pulsation of the myocardial cells. Intracellular ROS, cytoskeleton andmitochondrial membrane potential staining were detected at the end of co-culture.Nuclear magnetic resonance method were used to detect metabonomics changes ofthe RBC supernatant. Results1. We found a significant association between a longer mean RBC storage time and thepresence of the in-hospital “severe outcome”, and one day increase in mean RBCstorage time was associated with1.2(95%CI:1.032~1.401, p=0.018) folds risk ofincident “severe outcome”.2.14d and older RBC supernatant may stop myocardial cell beating when they wereco-culture3hours, and27.8％myocardial cells stopped beating in the14d group,44.4％stopped in the35d group. When the time extended to6hours,7d and olderRBC groups can stop myocardial cells beating significantly (p<0.001).3. Myocardial cell beating didn’t stop when the K+concentrationwas as much as28dRBC group, and the expression of ROS and change of cytoskeleton andmitochondrial membrane potential had no difference between the fresh and old RBCgroup. Study of nuclear magnetic resonance found that, with the extension of RBCstorage time, concentration of valine/leucine/isoleucine, lactate and alanineincreased, but citrate and sugar decreased (p<0.05).Conclusion1. Longer RBC storage time was independently associated with the postoperativesevere outcome. It was concluded that fresh RBC units should be used for theon-pump CABG patients.2.14d and older RBC supernatant can stop the beating of myocardial cells in vitro.3. It can be excluded that high concentration of K+, oxidative stress damage,cytoskeleton and mitochondrial damage as the main influence factor of stoppedbeating of myocardial cell induced by co-culture with the old RBC supernatant, butthe mechanism need further research.