Glycolytic intermediates and adenine nucleotides of human platelets. II. Effect of short-term storage at 4 C

The influence of storage time on the nucleotide concentration of canine platelets

Nucleotide concentrations of canine platelets during storage for 50 days were determined to find out the variation in the concentration of various nucleotides in canine platelets during storage at +4 degrees C for 50 days. Platelets of 3 dogs were stored in whole blood in PVC bags containing CPDA-1 stabilizer. The bags were kept at 4 degrees C for 50 days. Changes in the energy metabolism of the platelets during storage were determined by successive measurements of the following nucleotides: adenosine-diphosphate (ADP), adenosine-tri-phosphate (ATP) and guanosine-tri-phosphate (GTP). In preparation for the measurement of their nucleotide content, the platelets were isolated from the blood at regular intervals and their membranes destroyed by deep freezing, thawing, double sonification in ice and protein precipitation with perchloric acid. The concentration of nucleotides within the platelets was determined by "High Pressure Liquid Chromatography" (HPLC). ADP, ATP and GTP were identified in the peak areas of the HPLC using 3 different techniques: comparison of retention time of standard nucleotide solutions as control samples, enzyme tests and thin layer chromatography. Adenosine-mono-phosphate (AMP), adenosine, hypoxanthine and inosine mono 5'-phosphate (IMP) were not found in dog platelets. Platelet ATP concentration decreased significantly during 50 days of storage (p < 0.001), and was reduced to 24% of the concentration measured after 1 hour of storage on day 50. ADP concentration also dropped significantly during 50 days of storage (p < 0.001). On day 50 the average ADP concentration was reduced to about 34% of the concentration measured after 1 hour of storage.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered expression of platelet surface glycoproteins during storage

Human blood platelets were stored in autologous plasma at 4 degrees C or 22 degrees C and their surface changes were probed with three lectins--wheat germ agglutinin, lentil lectin and concanavalin A. Platelets stored at either temperature for different times showed increased sensitivity to lectins. Lectins which were nonagglutinating to fresh platelets readily agglutinated stored platelets. The platelets stored for 24 h or longer lost their ability to respond to thrombin but demonstrated enhanced aggregation with wheat germ agglutinin. Surface labelling experiments revealed progressive loss of a glycoprotein of Mr 150,000 (GPIb) together with the appearance of components with Mr 69,000, 60,000 and 25,000 respectively. New high molecular weight glycoproteins were detected only in stored platelets. These findings illustrate the usefulness of lectins for the detection of altered expression of surface glycoconjugates which may be a factor in storage related dysfunction of platelets.

Adenine in blood preservation

The recent Food and Drug Administration (U.S.) approval of a new blood preservative (CPDA-1) which contains adenine not only introduces a new blood product into the American blood banking system, but also heralds the advent of novel approaches to blood product preservation. The use of adenine to effect maintenance of red cell adenosine triphosphate (ATP), and hence to prolong storability, has a well-founded biochemical rationale. Effects of adenine on red cell metabolism are generally well understood, but effects on other blood components have not been fully delineated. The efficacy of adenine preservatives in enhancing the duration of red cell storage appears to outweigh the small risk of toxicity from free adenine. Clinical use of millions of units of adenine-preserved blood in Europe during more than a decade has resulted in only one report of possible adenine toxicity. Marginal acceptability of 24-hr 51Cr red cell recovery of packed red cells stored for 35 days in CPDA-1 has stimulated development and evaluation of an improved preservative (CPDA-2) which may extend blood storability beyond 35 days. A heightened awareness of the hematological consequences of prolonged storage has come with the extension of blood storage beyond 21 days. The concepts of component-specific preservation systems and optimal preservation systems have emerged as a result of experimentation on adenine preservatives. While the influence of adenine preservatives on American blood banking is yet to become manifest, the ultimte impact of adenine on blood preservation may be the development of novel systems which optimally preserve specific blood components at the option of the user.

Insignificance of gluconeogenesis in human blood platelets

Human blood platelets contain no detectable activity of the enzymes fructose diphosphatase (EC 3.1.3.11), phospho-enolpyruvate carboxykinase (EC 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1.). Glucose-6-phosphatase (EC 3.1.3.9) activity is very low. Phosphofructokinase present in human blood platelets, catalyzes a reaction which can be stimulated by AMP in a platelet homogenate, due to the presence of endogenous ADP and myokinase. These enzymes are responsible for the formation of fructose-6-phosphate from fructose-1, 6-diphosphate. Pyruvate kinase (EC 2.7.1.40) in human blood platelets belongs to the M-type, which is not inhibited by ATP, at least not under the conditions applied. The results obtained indicate that gluconeogenesis in human blood platelets is not present in the way which has been established for liver and kidney.