Identification of potential protein quality markers in pathogen inactivated and gamma-irradiated red cell concentrates

Peroxiredoxin 2: An Important Element of the Antioxidant Defense of the Erythrocyte

Peroxiredoxin 2 (Prdx2) is the third most abundant erythrocyte protein. It was known previously as calpromotin since its binding to the membrane stimulates the calcium-dependent potassium channel. Prdx2 is present mostly in cytosol in the form of non-covalent dimers but may associate into doughnut-like decamers and other oligomers. Prdx2 reacts rapidly with hydrogen peroxide (k > 10⁷ M^-1 s^-1). It is the main erythrocyte antioxidant that removes hydrogen peroxide formed endogenously by hemoglobin autoxidation. Prdx2 also reduces other peroxides including lipid, urate, amino acid, and protein hydroperoxides and peroxynitrite. Oxidized Prdx2 can be reduced at the expense of thioredoxin but also of other thiols, especially glutathione. Further reactions of Prdx2 with oxidants lead to hyperoxidation (formation of sulfinyl or sulfonyl derivatives of the peroxidative cysteine). The sulfinyl derivative can be reduced by sulfiredoxin. Circadian oscillations in the level of hyperoxidation of erythrocyte Prdx2 were reported. The protein can be subject to post-translational modifications; some of them, such as phosphorylation, nitration, and acetylation, increase its activity. Prdx2 can also act as a chaperone for hemoglobin and erythrocyte membrane proteins, especially during the maturation of erythrocyte precursors. The extent of Prdx2 oxidation is increased in various diseases and can be an index of oxidative stress.

General overview of blood products in vitro quality: Processing and storage lesions

Blood products are issued from blood collection. Collected blood is immediately mixed with anticoagulant solutions that immediately induce chemical and/or biochemical modifications. Collected blood is then transformed into different blood products according to various steps of fabrication. All these steps induce either reversible or irreversible "preparation-related" lesions that combine with "storage-related" lesions. This short paper aims to provide an overview of the alterations that are induced by the "non-physiological" processes used to prepare blood products that are used in clinical practice.

Proteomic analysis of red blood cells from donors exhibiting high hemolysis demonstrates a reduction in membrane-associated proteins involved in the oxidative response

BACKGROUND

The development of hemolysis during ex vivo hypothermic storage is multifaceted. Standardization of collection and production processes is used to minimize variability in biologics manufacturing and to maximize product quality. However, the influence of various donor characteristics on product quality is often difficult to evaluate and to control. Using a proteomic approach, we aimed to decipher relevant donor characteristics that may predict red blood cell (RBC) quality during storage.

STUDY DESIGN AND METHODS

Ten healthy volunteer donors exhibiting repeated high hemolysis at outdate (>0.8%; RBC^HH ) and 10 age- and sex-matched control donors (RBC^Ctrl ) were studied. Common quality variables were measured on Days 5, 14, 21, 28, and 42 of storage. Protein profiles of hemoglobin-depleted membrane fractions from RBC^HH and RBC^Ctrl donors were analyzed using a quantitative proteomics approach based on iTRAQ (isobaric tags for relative and absolute quantitation).

RESULTS

Time-dependent lesion development was apparent in both donor populations. RBC^HH exhibited reduced 2,3-bisphosphoglycerate levels (p < 0.001) and morphologic score (p < 0.001), but displayed elevated hemolysis level (p < 0.001), RBC-derived microvesicle formation (p < 0.001), and mean corpuscular fragility (p < 0.001) compared to RBC^Ctrl , indicating notable differences at the membrane between the two donor populations. Proteomic findings revealed a significant reduction in the level of proteins involved in oxidative response pathways at early time points in RBC^HH compared to that of RBC^Ctrl .

CONCLUSION

The recruitment of these candidate proteins might be part of a response mechanism altered in RBC^HH donors and therefore may be useful as a donor screening tool.