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Blood Bank

Rejuvenated RBCs

This is a fascinating, though not very commonly used, process aimed at turning back the metabolic clock on stored red cells, at least partially! Think of it like giving older RBCs an energy drink before they head out for transfusion

What Are Rejuvenated Red Blood Cells?

  • Definition: Rejuvenated RBCs are units of stored Red Blood Cells that have been treated in vitro (in the lab) with a special chemical solution designed to restore intracellular levels of ATP (adenosine triphosphate) and 2,3-Diphosphoglycerate (2,3-DPG), which normally decline during storage
  • Goal: To reverse some key aspects of the RBC “storage lesion,” specifically the metabolic decline, potentially improving the function and viability of the cells, especially those nearing their expiration date

The Rejuvenation Process

This isn’t just adding a drop of something; it’s a specific laboratory procedure:

  1. Selection of RBC Unit Often, units nearing their original expiration date (e.g., > 30 days old) are chosen, although fresher units can also be rejuvenated, particularly if intended for freezing
  2. Addition of Rejuvenation Solution A sterile, FDA-approved rejuvenation solution is added to the RBC unit. These solutions typically contain substrates that fuel the RBC metabolic pathways:
    • Pyruvate
    • Inosine: (a precursor for ATP synthesis via alternative pathways)
    • Phosphate
    • Adenine
    • (Often referred to collectively by the acronym PIPA)
  3. Incubation The mixture of RBCs and rejuvenation solution is incubated, usually in a water bath at 37°C, for a specific period (often around 1 hour) to allow the metabolic restoration to occur
  4. Post-Incubation Processing (CRITICAL STEP)
    • The rejuvenation solution itself contains substances (like inosine) that are not safe for direct intravenous infusion and the process creates a hypertonic environment
    • Therefore, after incubation, the rejuvenated RBCs MUST be processed further:
      • Washing: The most common next step is to extensively wash the RBCs using an automated cell washer with sterile saline. This removes the rejuvenation solution chemicals and any accumulated metabolic byproducts. This washing step makes the unit an OPEN SYSTEM.
      • Glycerolization and Freezing: Alternatively, rejuvenated RBCs can be glycerolized and frozen immediately after rejuvenation (following standard freezing protocols). This preserves the restored ATP/2,3-DPG levels for long-term storage. These units will then require thawing and deglycerolization (washing) before transfusion

Indications for Use / Purpose

Rejuvenation is not a routine procedure. Its use is limited to specific situations:

  • Salvaging Near-Expiry RBC Units: The primary historical use was to “rescue” valuable RBC units (especially rare phenotypes) close to their outdate by restoring metabolic function, allowing them to be used or frozen
  • Improving Oxygen Delivery Characteristics (Restoring 2,3-DPG): Restoring 2,3-DPG levels lowers hemoglobin’s oxygen affinity, theoretically improving oxygen release to tissues immediately after transfusion. This might be considered for specific patient populations where immediate oxygen offloading is critical (e.g., massive transfusion, certain cardiac surgeries, neonatal exchange transfusions), although the clinical benefit over using fresh, non-rejuvenated units is debated and not definitively proven for most scenarios
  • Enhancing Quality for Cryopreservation (Freezing): Rejuvenating RBCs before freezing can improve their post-thaw viability and quality

Properties of Rejuvenated (and Washed) RBCs

  • Restored ATP/2,3-DPG: Levels are typically restored to, or even exceed, those found in fresh blood
  • Improved Oxygen Release: Lower oxygen affinity due to restored 2,3-DPG
  • Storage Lesion Effects Remain: Rejuvenation primarily addresses ATP/2,3-DPG; it does not fully reverse other storage-related changes like membrane loss, shape changes, or oxidative damage
  • Washed Product: The final transfusable product (unless frozen) is RBCs suspended in saline, essentially free of plasma, additive solution, and rejuvenation chemicals. It is also leukocyte-reduced (if the original unit was) and has low potassium levels

Storage and Expiration

This is dictated by the mandatory post-rejuvenation processing:

  • After Rejuvenation and Washing (Open System)
    • Storage Temperature: 1°C to 6°C
    • Expiration: 24 hours from the time of washing (due to open system bacterial risk)
  • After Rejuvenation, Freezing, Thawing, and Deglycerolization (Open System)
    • Frozen Storage: 10 years at ≤ -65°C
    • Post-Thaw/Deglycerolization Storage: 24 hours at 1-6°C

Administration

  • Compatibility: Standard ABO/Rh typing and crossmatch procedures are required
  • Filtration: Administer through a standard blood filter (170-260 microns)
  • Infusion Time: Must be completed within 4 hours of spiking the bag or removal from controlled 1-6°C storage (and within the 24-hour post-wash expiration)

Advantages

  • Restores Key Metabolites: Effectively increases ATP and 2,3-DPG levels
  • Potential for Improved Oxygen Delivery: Theoretically beneficial in specific high-need situations
  • Salvages Near-Expiry Units: Reduces wastage of valuable units
  • Improves Quality for Freezing: Leads to better post-thaw recovery

Disadvantages / Limitations

  • Complex and Costly Process: Requires special solutions, incubation equipment, and mandatory extensive washing (similar to deglycerolization)
  • Time-Consuming: Not suitable for urgent transfusion needs
  • Open System Risk: Washing step increases potential for bacterial contamination
  • Short Post-Wash Shelf Life (24 hours): Significant logistical constraint, requires careful coordination
  • Limited Proven Clinical Benefit: Widespread use is not supported by strong evidence demonstrating superior outcomes compared to standard transfusion practices for most patients
  • Availability: Rejuvenation solutions and protocols are not implemented in all blood centers or transfusion services

Key Terms

  • Rejuvenation: The in vitro process of restoring ATP and 2,3-DPG levels in stored RBCs
  • Storage Lesion: The sum of biochemical and morphological changes occurring in stored RBCs
  • ATP (Adenosine Triphosphate): The main energy currency of cells
  • 2,3-DPG (2,3-Diphosphoglycerate): Molecule that regulates hemoglobin’s oxygen affinity
  • Rejuvenation Solution (PIPA): Solution containing Pyruvate, Inosine, Phosphate, Adenine used to restore RBC metabolism
  • Washing: Mandatory post-rejuvenation step to remove solution chemicals, typically creating an open system
  • Cryopreservation: Freezing of cells for long-term storage (often follows rejuvenation)
  • Open System: Processing method potentially compromising sterility, leading to shortened expiration