The Effect of Incubation and Storage on Human Platelet Structure as Studied by Electron Microscopy.

D ESPITE the well-known susceptibility of platelets to damage on handling or storage comparatively little has been written about the changes which platelets undergo on incubation or storage. Nevertheless, numerous studies have been undertaken employing platelets incubated at 37 C. for various times to study certain aspects of their metabolism,’ or preincubating them with enzymes2 or radioisotopes’ to study their behavior in certain in vitro conditions. It is obvious that interpretations of such experiments could be fallacious unless allowance is made for the effect of incubation itself. Platelet transfusions may be strikingly effective in certain clinical situations4’5 and radiation injury,0 but their routine usage is precluded by a number of practical problems. One of the most important of these is the lack of the practical method for storing platelets so that they can retain their viability and a platelet transfusion bank be established. Most attempts to prolong platelet viability during storage have followed technics successfully employed for the erythrocyte, such as nucleotide “additives,”7 but while yielding useful information they have not completely answered this problem. This is not surprising when the in vivo life span, structural, and metabolic differences between the platelet and erythrocyte are considered.8 The present study was undertaken in an attempt to define the morphologic and certain chemical changes occurring in platelets during incubation and storage, to enable a better understanding of, and perhaps approach, to the above problems. These studies suggest that autolytic or lysosomal activity in the platelet may be a major factor in the platelet’s susceptibility to handling and storage, and show that marked morphologic and metabolic changes may occur within the platelet after short periods of in vitro incubation.