Evaluation of stored whole blood cellular components treated with bactericidal peptides at a higher concentration than required to assess the peptide compatibility with product quality

Abstract

Background - Despite advancements in screening and pathogen detection, bacterial contamination of whole blood (WB) remains a rare but critical risk, typically originating from donor blood or skin-resident bacteria. While current pathogen reduction technologies (PRT) mitigate this risk, they often compromise blood quality relative to the untreated units. As an alternative, we recently evaluated two synthetic peptides, D-CONGA and D-CONGA-Q7 in WB at a concentration of ~8 μM for bactericidal efficacy and compatibility with WB hemostasis potential. However, evaluation of hemostasis property of WB alone is insufficient to ensure that endogenous red blood cells (RBC) and platelets are maintaining other critical functional parameters that are measurable in vitro.

Materials and methods - We investigated the effects of these peptides on the WB endogenous RBC and platelets at ~2.5 times higher concentration (i.e., 20 μM) than what is required (8 μM) for complete bactericidal activity to test their compatibility limits. We investigated the performance of WB endogenous RBC resident hemoglobin oxygen affinity and glycolytic rate as well as WB endogenous platelet aggregation potential as part of monitoring the safety and compatibility profile of the peptides.

Results - Our results support that even higher peptide concentrations do not significantly affect oxygen dissociation from red blood cells but do cause a slight deviation in P50 values and a marginal difference in glycolytic rate. Further, WB endogenous platelet aggregation is not affected by the peptide treatment with any of the aggregation agonists used.

Discussion - Overall, we conclude that while higher peptide concentrations (20 μM) than required for bactericidal activity (~8 μM) may slightly affect glycolysis and the ability of red blood cells to dissociate from oxygen, platelet aggregation is not affected. This report clearly supports the potential safe use of these peptides for inactivating bacteria in WB without harming the product quality.