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Prolonged storage of red cells: the effect of pH, adenine and phosphate
D Mazor1, A Dvilansky, N Meyerstein
1Hematology Service, Corob Medical Research Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Abstract:
Prolonged storage of red blood cells (RBCs) at 4 degrees C results in decreased intracellular ATP levels with diminished posttransfusion survival. Meryman described a preservative medium, exceptional in its capacity to increase these intracellular levels during the first weeks of storage and later in maintaining adequate levels, for extended storage periods. We modified this medium, investigated its constituents, and found that its ATP-preserving effect was unrelated to its tonicity or to the presence of mannitol. Throughout storage, RBC potassium leakage and lactate production were moderate. No evidence of osmotic swelling was detected. In spite of high ATP levels, the cells became echinocytes, thus discounting a direct correlation between shape and metabolic status. The most striking finding in this study was that the prestorage pH of the blood unit (pH 7.0), has a crucial contribution in elevating nucleotide levels in a medium containing high levels of phosphate (18-40 mM) and adenine. We suggest that a combined effect of optimal pH, adenine, glucose and phosphate in the medium contributes to the ability of the RBCs to synthesize the necessary purine nucleotides by the 'salvage pathway'.
Insights
Optimizing red blood cell (RBC) storage involves maintaining adenosine triphosphate (ATP) levels. A modified Meryman medium with specific pH, phosphate, and adenine enhances ATP preservation for extended RBC storage.
Area of Science:
- Biochemistry
- Hematology
- Cell Biology
Background:
- Prolonged storage of red blood cells (RBCs) at 4°C decreases intracellular adenosine triphosphate (ATP) levels, impacting posttransfusion survival.
- Meryman's preservative medium enhances ATP levels during early storage and maintains them for extended periods.
Purpose of the Study:
- To investigate the constituents of a modified Meryman medium responsible for preserving RBC ATP levels.
- To determine the factors contributing to enhanced nucleotide synthesis in stored RBCs.
Main Methods:
- Modification of Meryman's RBC preservative medium.
- Investigation of medium constituents (tonicity, mannitol, phosphate, adenine) and their effect on ATP levels.
- Monitoring of RBC potassium leakage, lactate production, and cell morphology (echinocytes) during storage.
- Analysis of the impact of prestorage pH on nucleotide levels.
Main Results:
- The ATP-preserving effect was independent of tonicity and mannitol.
- Moderate potassium leakage and lactate production were observed, with no osmotic swelling.
- High ATP levels did not correlate with normal RBC shape (echinocytes formed).
- Prestorage pH of 7.0 was crucial for elevating nucleotide levels in the presence of high phosphate and adenine.
Conclusions:
- A combination of optimal pH (7.0), adenine, glucose, and phosphate in the storage medium facilitates RBC purine nucleotide synthesis via the salvage pathway.
- This optimized medium composition enhances RBC preservation for extended storage periods.
- RBC shape (echinocyte formation) is not a direct indicator of metabolic status (ATP levels).