L-carnitine decreases glycolysis in liquid-stored platelets.
BACKGROUND
The platelet storage lesion is characterized metabolically by a pH decrease associated with lactic acid generation; a change in platelet morphology from discoid to spherical; a diminished response to in vitro challenge tests, such as the hypotonic shock response (HSR) and extent of shape change (ESC); increased surface P-selectin expression; and decreased in vivo recovery and survival. Altering storage conditions to improve these measures could allow for extension of the duration of in vitro storage.


METHODS
ABO-identical paired platelet concentrates were pooled and then equally divided into two plastic bags. Either L-carnitine (LC) or an equal volume of saline (control) was added to one container of each pair. Platelets were stored at 20 to 24 degrees C for 5 to 10 days or at 1 to 6 degrees C for 5 days at various concentrations of LC between 0.1 and 15 mM: At the end of storage, pH, glucose consumption, lactate generation, HSR, ESC, and surface P-selectin expression were measured. In different experiments, paired platelet concentrates were spiked with a Staphylococcus epidermidis suspension in the presence and absence of L-carnitine at a concentration of 5 mM:


RESULTS
At 20 to 24 degrees C and concentrations of LC between 0.1 and 5 mM:, there was evidence of better pH preservation, less glucose consumption, and less lactate generation. Only with storage beyond 5 days was a difference present in either surface P-selectin expression or HSR. An L-carnitine concentration of 5 mM: appeared optimal. L-carnitine did not enhance the growth of bacteria after 7 to 8 days of storage.


CONCLUSIONS
LC at 5 mM: may improve the quality of platelet concentrates that are stored beyond 5 days. There was no indication that LC at this concentration would promote bacterial growth. It may be a useful additive to platelet preservation.
Sweeney
J D
JD
Herbert C. Lichtmann Blood Bank and Transfusion Medicine Research Unit, The Miriam Hospital, Providence, Rhode Island 01906, USA. jsweeney@lifespan.org
Blair
A J
AJ
Cheves
T A
TA
Dottori
S
S
Arduini
A
A
D001792:Blood Platelets / Q000378:metabolism; D001793:Blood Preservation; D002331:Carnitine / Q000494:pharmacology*; D015925:Cryopreservation; D004305:Dose-Response Relationship, Drug; D006019:Glycolysis / Q000187:drug effects; D013997:Time Factors
D002331:Carnitine