Background/Case Studies: The views expressed in this abstract are those of the author(s) and do not reflect the official policy or position of the U.S. Army Medical Department, Department of the Army, DoD, or the U.S. Government.
Platelet transfusions are lifesaving interventions. Increasing the shelf-life of platelets increases the availability of platelets for transfusion. Platelet Additive Solutions (PAS) are electrolyte solutions that contain specific ingredients with the goal of extending storage time. This study aimed to evaluate the effect of the chemical composition of PAS on the ATP levels of platelets in cold storage.
Study
Design/Methods: Donor blood was collected into sodium citrate. Washed platelets were resuspended in experimental PAS, loaded into a 96-well plate, covered with a breathable membrane and stored overnight at 4C. The next day, a Cell Titer-Glo® 2.0 luminescence assay was performed to assess ATP levels.
The first experiment (n=4) tested Intersol, Isoplate, 0.9% sodium chloride (NaCl), lactated Ringer’s (LR), and Plasmalyte, with and without 100 mg/dL glucose. The second experiment (n=5) tested the same five solutions with all solutions pH balanced to 7.4 with and without phosphate buffering (4 mM). The third experiment (n=5) tested the effect of added glucose. The fourth experiment (n=5) tested the effect of added pyruvate.
Generalized linear mixed modelling was used to determine the effect of PAS components on luminescence. Results were adjusted for multiple comparisons with a Tukey-Kramer adjustment. Statistical significance was accepted at p< 0.05. Data is reported as mean ± standard deviation of luminescence in arbitrary units (x 10^ 6 AU).
Results/Findings: Luminescence in Isoplate (3.82 ± 0.66) and Intersol (3.61 ± 0.68) was higher than Plasmalyte (1.93 ± 0.23), NaCl (2.20 ± 0.39), and LR (2.86 ± 0.31; all p< 0.0001); 100 mg/dL of glucose increased the average luminescence by 0.28 (p=0.005).
Luminescence in pH balanced Plasmalyte was greater than in pH balanced NaCl (3.45 ± 0.48 vs. 2.54 ± 0.31, p< 0.0001) and in pH balanced LR (3.45 ± 0.48 vs. 2.08 ± 0.39, p< 0.0001). Luminescence in pH balanced NaCl was also greater than that in pH balanced LR (2.54 ± 0.31 vs. 2.08 ± 0.39, p=0.006).
Luminescence in 500 mg/dL glucose (3.14 ± 0.68) was greater than the control group (2.86 ± 0.66, p=0.007). Additionally, pH balanced and phosphate buffered Plasmalyte had a higher luminescence than Isoplate (3.09 ± 0.66 vs. 2.94 ± 0.62, p=0.009).
Luminescence in 5 mM pyruvate (2.81 ± 0.20) was greater than in 0.1 mM pyruvate (2.56 ±0.19, p=0.0008) and the control group (2.51 ± 0.27, p< 0.0001). The luminescence in 1 mM pyruvate (2.73 ± 0.25) was greater than the group treated with 0.1 mM pyruvate (2.56 ± 0.19, p=0.03) and the control group (2.51 ± 0.27, p=0.004). Conclusions: These studies demonstrate that platelet bioenergetic status is sensitive to the pH of the storage media and available fuel substrates.
Importance of research: These results indicate that further optimization of platelet storage conditions is possible, potentially leading to an increase in storage duration for cold-stored platelets. Future research in our laboratory will focus on continuing to optimize fuel substrate concentrations and buffering capacity, with the goal of reaching 21 days of cold storage for platelets.
