Red blood cell transfusion-induced non-transferrin-bound iron promotes Pseudomonas aeruginosa biofilms in human sera and mortality in catheterized mice

Red Blood Cell Storage: From Genome to Exposome Towards Personalized Transfusion Medicine

Over the last decade, the introduction of omics technologies-especially high-throughput genomics and metabolomics-has contributed significantly to our understanding of the role of donor genetics and nongenetic determinants of red blood cell storage biology. Here we briefly review the main advances in these areas, to the extent these contributed to the appreciation of the impact of donor sex, age, ethnicity, but also processing strategies and donor environmental, dietary or other exposures - the so-called exposome-to the onset and severity of the storage lesion. We review recent advances on the role of genetically encoded polymorphisms on red cell storage biology, and relate these findings with parameters of storage quality and post-transfusion efficacy, such as hemolysis, post-transfusion intra- and extravascular hemolysis and hemoglobin increments. Finally, we suggest that the combination of these novel technologies have the potential to drive further developments towards personalized (or precision) transfusion medicine approaches.

Plasma non-transferrin-bound iron uptake by the small intestine leads to intestinal injury and intestinal flora dysbiosis in an iron overload mouse model and Caco-2 cells

Iron overload often occurs during blood transfusion and iron supplementation, resulting in the presence of non-transferrin-bound iron (NTBI) in host plasma and damage to multiple organs, but effects on the intestine have rarely been reported. In this study, an iron overload mouse model with plasma NTBI was established by intraperitoneal injection of iron dextran. We found that plasma NTBI damaged intestinal morphology, caused intestinal oxidative stress injury and reactive oxygen species (ROS) accumulation, and induced intestinal epithelial cell apoptosis. In addition, plasma NTBI increased the relative abundance of Ileibacterium and Desulfovibrio in the cecum, while the relative abundance of Faecalibaculum and Romboutsia was reduced. Ileibacterium may be a potential microbial biomarker of plasma NTBI. Based on the function prediction analysis, plasma NTBI led to the weakening of intestinal microbiota function, significantly reducing the function of the extracellular structure. Further investigation into the mechanism of injury showed that iron absorption in the small intestine significantly increased in the iron group. Caco-2 cell monolayers were used as a model of the intestinal epithelium to study the mechanism of iron transport. By adding ferric ammonium citrate (FAC, plasma NTBI in physiological form) to the basolateral side, the apparent permeability coefficient (Papp) values from the basolateral to the apical side were greater than 3×10-6 cm s-1. Intracellular ferritin level and apical iron concentration significantly increased, and SLC39A8 (ZIP8) and SLC39A14 (ZIP14) were highly expressed in the FAC group. Short hairpin RNA (shRNA) was used to knock down ZIP8 and ZIP14 in Caco-2 cells. Transfection with ZIP14-specific shRNA decreased intracellular ferritin level and inhibited iron uptake. These results revealed that plasma NTBI may cause intestinal injury and intestinal flora dysbiosis due to the uptake of plasma NTBI from the basolateral side into the small intestine, which is probably mediated by ZIP14.

Red Blood Cell Transfusions Are Not Associated With Incident Complications or Poor Outcomes in Patients With Intracerebral Hemorrhage

Background Anemia is associated with poor intracerebral hemorrhage (ICH) outcomes, yet the relationship of red blood cell (RBC) transfusions to ICH complications and functional outcomes remains unclear. We investigated the impact of RBC transfusion on hospital thromboembolic and infectious complications and outcomes in patients with ICH. Methods and Results Consecutive patients with spontaneous ICH enrolled in a single-center, prospective cohort study from 2009 to 2018 were assessed. Primary analyses assessed relationships of RBC transfusions on incident thromboembolic and infectious complications occurring after the transfusion. Secondary analyses assessed relationships of RBC transfusions with mortality and poor discharge modified Rankin Scale score 4 to 6. Multivariable logistic regression models adjusted for baseline demographics and medical disease severity (Acute Physiology and Chronic Health Evaluation II), and ICH severity (ICH score).Of 587 patients with ICH analyzed, 88 (15%) received at least one RBC transfusion. Patients receiving RBC transfusions had worse medical and ICH severity. Though patients receiving RBC transfusions had more complications at any point during the hospitalization (64.8% versus 35.9%), we found no association between RBC transfusion and incident complications in our regression models (adjusted odds ratio [aOR], 0.71 [95% CI, 0.42-1.20]). After adjusting for disease severity and other relevant covariates, we found no significant association between RBC transfusion and mortality (aOR, 0.87 [95% CI, 0.45-1.66]) or poor discharge modified Rankin Scale score (aOR, 2.45 [95% CI, 0.80-7.61]). Conclusions In our cohort with ICH, RBC transfusions were expectedly given to patients with higher medical and ICH severity. Taking disease severity and timing of transfusions into account, RBC transfusion was not associated with incident hospital complications or poor clinical ICH outcomes.

Red Blood Cell Omics and Machine Learning in Transfusion Medicine: Singularity Is Near

Background

Blood transfusion is a life-saving intervention for millions of recipients worldwide. Over the last 15 years, the advent of high-throughput, affordable omics technologies - including genomics, proteomics, lipidomics, and metabolomics - has allowed transfusion medicine to revisit the biology of blood donors, stored blood products, and transfusion recipients.

Summary

Omics approaches have shed light on the genetic and non-genetic factors (environmental or other exposures) impacting the quality of stored blood products and efficacy of transfusion events, based on the current Food and Drug Administration guidelines (e.g., hemolysis and post-transfusion recovery for stored red blood cells). As a treasure trove of data accumulates, the implementation of machine learning approaches promises to revolutionize the field of transfusion medicine, not only by advancing basic science. Indeed, computational strategies have already been used to perform high-content screenings of red blood cell morphology in microfluidic devices, generate in silico models of erythrocyte membrane to predict deformability and bending rigidity, or design systems biology maps of the red blood cell metabolome to drive the development of novel storage additives.

Key Message

In the near future, high-throughput testing of donor genomes via precision transfusion medicine arrays and metabolomics of all donated products will be able to inform the development and implementation of machine learning strategies that match, from vein to vein, donors, optimal processing strategies (additives, shelf life), and recipients, realizing the promise of personalized transfusion medicine.

The clinical relevance of detectable plasma iron species in iron overload states and subsequent to intravenous iron-carbohydrate administration

Many disorders of iron homeostasis (e.g., iron overload) are associated with the dynamic kinetic profiles of multiple non-transferrin bound iron (NTBI) species, chronic exposure to which is associated with deleterious end-organ effects. Here we discuss the chemical nature of NTBI species, challenges with measuring NTBI in plasma, and the clinical relevance of NTBI exposure based on source (iron overload disorder vs. intravenous iron-carbohydrate complex administration). NTBI is not a single entity but consists of multiple, often poorly characterized species, some of which are kinetically non-exchangeable while others are relatively exchangeable. Prolonged presence of plasma NTBI is associated with excessive tissue iron accumulation in susceptible tissues, with consequences, such as endocrinopathy and heart failure. In contrast, intravenous iron-carbohydrate nanomedicines administration leads only to transient NTBI appearance and lacks evidence for association with adverse clinical outcomes. Assays to measure plasma NTBI are typically technically complex and remain chiefly a research tool. There have been two general approaches to estimating NTBI: capture assays and redox-activity assays. Early assays could not avoid capturing some iron from transferrin, thus overestimating NTBI. By contrast, some later assays may have promoted the donation of NTBI species to transferrin during the assay procedure, potentially underestimating NTBI levels. The levels of transferrin saturation at which NTBI species have been detectable have varied between different methodologies and between patient populations studied.

Allogeneic Red Blood Cell Transfusion and Infectious Complications Following Pediatric Spinal Fusion: NSQIP-P Analysis

Substantial bleeding occurs during spinal fusion surgery in the pediatric population, and many patients receive allogeneic red blood cell transfusion (ARBT) for the treatment of resulting perioperative anemia. ARBT is thought to increase vulnerability to postoperative infections following major surgical procedures, but studies of this relationship in children undergoing spinal fusion have yielded conflicting results.