Dependence of the number of platelets maintaining aerobic metabolism on the size of storage containers.

In order to elucidate the role of the size (surface area) of the storage container in maintaining the oxidative metabolism of platelets during in vitro storage at 22 degrees C, human platelets were stored as platelet concentrates (PC) with plasma in conventional polyvinylchloride plastic containers of various sizes for 3 days at 22 degrees C. Oxygen permeability of the container was 1.5 nmole/min/atm/cm2. Levels of the partial oxygen pressure (PO2) of PC depended on both container size and total number of platelets. The larger the containers, the higher was the PO2. PO2 linearly decreased to 16 mmHg with increasing platelet number. In well-oxygenated PC, 93% of the total ATP production was through the oxidative phosphorylation. With further increases in platelet number in the container, PO2 maintained low levels. The increases in glucose consumption and concomitant lactate production occurred to compensate the oxygen debt. The pH fall in PC depended on the degree of glycolysis. The partial carbon dioxide pressure (PCO2) increased with increasing platelet number. However, the larger the container, the lower was the PCO2. When PC were stored in 6 different-sized containers, the number of platelets, at which PO2 was 16 mmHg, was correlated with the size of the container. The present data indicate that the amounts of oxygen entering a container, which depended on container size, may determine the number of platelets maintaining oxidative metabolism.