Metabolic rejuvenation upgrades circulatory functions of red blood cells stored under blood bank conditions.

BACKGROUND: Red blood cells (RBC) change upon hypothermic conservation, and storage for 6 weeks is associated with the short-term clearance of 15% to 20% of transfused RBCs. Metabolic rejuvenation applied to RBCs before transfusion replenishes energetic sources and reverses most storage-related alterations, but how it impacts RBC circulatory functions has not been fully elucidated. STUDY DESIGN AND METHODS: Six RBC units stored under blood bank conditions were analyzed weekly for 6 weeks and rejuvenated on Day 42 with an adenine-inosine-rich solution. Impact of storage and rejuvenation on adenosine triphosphate (ATP) levels, morphology, accumulation of storage-induced microerythrocytes (SMEs), elongation under an osmotic gradient (by LORRCA), hemolysis, and phosphatidylserine (PS) exposure was evaluated. The impact of rejuvenation on filterability and adhesive properties of stored RBCs was also assessed. RESULTS: Rejuvenation of RBCs restored intracellular ATP to almost normal levels and decreased the PS exposure from 2.78% to 0.41%. Upon rejuvenation, the proportion of SME dropped from 28.2% to 9.5%, while the proportion of normal-shaped RBCs (discocytes and echinocytes 1) increased from 47.7% to 67.1%. In LORCCA experiments, rejuvenation did not modify the capacity of RBCs to elongate and induced a reduction in cell volume. In functional tests, rejuvenation increased RBC filterability in a biomimetic splenic filter (+16%) and prevented their adhesion to endothelial cells (-87%). CONCLUSION: Rejuvenation reduces the proportion of morphologically altered and adhesive RBCs that accumulate during storage. Along with the improvement in their filterability, these data show that rejuvenation improves RBC properties related to their capacity to persist in circulation after transfusion.

Age of transfused red blood cells and health outcomes in two surgical cohorts.

RATIONALE: Red blood cells (RBC) undergo morphologic and biochemical changes during storage which may lead to adverse health risks upon transfusion. In prior studies, the effect of RBC age on health outcomes has been conflicting. We designed the study to assess the effects of RBC units' storage duration on health outcomes specifically for hospitalized patients undergoing hip fracture surgery or coronary artery bypass grafting (CABG) surgery. METHODS: Using International Classification of Diseases (ICD) 9 codes, hip fracture surgery and CABG surgery patients, who received RBC transfusions between 2008 and 2013, were retrospectively identified from the electronic medical records system. Hip fracture surgery and CABG cohorts were sub-divided into 3 blood age groups based upon RBC unit age at the time of transfusion: young blood (RBC units stored less than or equal to 14 days), old blood (RBC units were stored for greater than or equal to 28 days), or mixed blood for the remaining patients. Outcome variables were 30-day, 90-day, and inpatient mortality as well as hospital length of stay. RESULTS: A total of 3,182 patients were identified: 1,121 with hip fractures and 2,061 with CABG. Transfusion of old blood was associated with higher inpatient mortality in the hip fracture surgery cohort (OR 166.8, 95% CI 1.067-26064.7, p = 0.04) and a higher 30-day mortality in the CABG cohort (OR 4.55, 95% CI 1.01-20.49, p = 0.03). CONCLUSIONS: Transfusing RBC units stored for greater than or equal to 28 days may be associated with a higher mortality for patients undergoing hip fracture or CABG.