A randomized trial of blood donor iron repletion on red cell quality for transfusion and donor cognition and well-being

Arginine metabolism is a biomarker of red blood cell and human aging

Increasing global life expectancy motivates investigations of molecular mechanisms of aging and age-related diseases. This study examines age-associated changes in red blood cells (RBCs), the most numerous host cell in humans. Four cohorts, including healthy individuals and patients with sickle cell disease, were analyzed to define age-dependent changes in RBC metabolism. Over 15,700 specimens from 13,757 humans were examined, a major expansion over previous studies of RBCs in aging. Multi-omics approaches identified chronological age-related alterations in the arginine pathway with increased arginine utilization in RBCs from older individuals. These changes were consistent across healthy and sickle cell disease cohorts and were influenced by genetic variation, sex, and body mass index. Integrating multi-omics data and metabolite quantitative trait loci (mQTL) in humans and 525 diversity outbred mice functionally linked metabolism of arginine during RBC storage to increased vesiculation-a hallmark of RBC aging-and lower post-transfusion hemoglobin increments. Thus, arginine metabolism is a biomarker of RBC and organismal aging, suggesting potential new targets for addressing sequelae of aging.

It's in your blood: The impact of age, sex, genetic factors and exposures on stored red blood cell metabolism

Transfusion of packed red blood cell (RBCs) saves millions of lives yearly worldwide, making packed RBCs the most commonly administered drug in hospitals after vaccines. However, not all blood units are created equal. By examining blood products as they age in blood banks, transfusion scientists are gaining insights into the intricacies of human chemical individuality as regulated by biological factors (such as sex, age, and body mass index), genetic and non-genetic factors like environmental, dietary, and other exposures. Here, we review recent literature on this topic, with an emphasis on studies linking genetic traits to the metabolic heterogeneity of blood products, the hemolytic propensity of stored RBCs, and transfusion outcomes in both healthy autologous and non-autologous patients requiring transfusion. Given the role of RBCs as a simplified model of eukaryotic cells, and RBC storage as a medically relevant application modeling erythrocyte responses to oxidant stress, these insights have the potential not only to guide the development of precision transfusion strategies, but also to identify novel mechanisms of RBC metabolic regulation relevant to responses to hypoxia and oxidant stress in human (patho)physiology.

Iron deficiency-related symptoms in non-anemic whole blood donors

INTRODUCTION

Whole blood donors are at increased risk for iron deficiency (ID). ID anemia is associated with several symptoms, such as fatigue, cognitive dysfunction, pica, and restless leg syndrome (RLS). However, it is unclear if these symptoms also occur when a donor has developed ID without anemia. This study aims to determine whether non-anemic ID (NAID) is associated with the occurrence of ID-related symptoms.

STUDY DESIGNS AND METHODS

We combined data from three studies in whole blood donors (i.e., Donor Insight-III, FIND'EM, and FORTE) to create a substantial sample size (N = 12,143). The self-reported occurrence and severity of ID-related symptoms, such as physical and mental health, fatigue, cognitive functioning, pica, and RLS, was measured using validated questionnaires. Associations were studied using logistic regression modeling with ID-related symptoms derived from the questionnaires as the dependent variable and ferritin level group (0-15 μg/L, 15-30 μg/L, and >30 μg/L) as explanatory variable.

RESULTS

After applying inclusion and exclusion criteria, 9829 donors were eligible for analysis. In the models corrected for age, body mass index, Hb level, and cohort, only fatigue was shown to be associated with ferritin levels in men, showing lower odds (OR 1.41, 95% CI 1.11-1.79) for fatigue with higher ferritin levels.

CONCLUSION

In these studies, NAID was only associated with self-reported fatigue in male donors. Although selection bias may have led to underestimated associations, ferritin measurements in donors should be primarily considered as a measure to prevent anemia, rather than to prevent or mitigate NAID-related symptoms.

Biological and genetic determinants of glycolysis: Phosphofructokinase isoforms boost energy status of stored red blood cells and transfusion outcomes

Mature red blood cells (RBCs) lack mitochondria and thus exclusively rely on glycolysis to generate adenosine triphosphate (ATP) during aging in vivo or storage in blood banks. Here, we leveraged 13,029 volunteers from the Recipient Epidemiology and Donor Evaluation Study to identify associations between end-of-storage levels of glycolytic metabolites and donor age, sex, and ancestry-specific genetic polymorphisms in regions encoding phosphofructokinase 1, platelet (detected in mature RBCs); hexokinase 1 (HK1); and ADP-ribosyl cyclase 1 and 2 (CD38/BST1). Gene-metabolite associations were validated in fresh and stored RBCs from 525 Diversity Outbred mice and via multi-omics characterization of 1,929 samples from 643 human RBC units during storage. ATP and hypoxanthine (HYPX) levels-and the genetic traits linked to them-were associated with hemolysis in vitro and in vivo, both in healthy autologous transfusion recipients and in 5,816 critically ill patients receiving heterologous transfusions, suggesting their potential as markers to improve transfusion outcomes.

Effectiveness of ferritin-guided donation intervals in whole-blood donors in the Netherlands (FIND'EM): a stepped-wedge cluster-randomised trial

BACKGROUND

Whole-blood donors are at increased risk for iron deficiency and anaemia. The current standard of haemoglobin monitoring is insufficient to ensure the maintenance of proper iron reserves and donor health. We aimed to determine the effects of ferritin-guided donation intervals for blood donor health and blood supply in the Netherlands.

METHODS

In this stepped-wedge cluster-randomised trial (FIND'EM), the 138 fixed and mobile donation centres in the Netherlands are organised into 29 geographical clusters and the clusters were randomly assigned to four treatment groups, with two groups being further split into two per a protocol amendment. Eligible donors were whole-blood donors who consented for use of their leftover material in the study. Each group was sequentially crossed over from the existing policy (haemoglobin-based screening; control) to a ferritin-guided donation interval policy over a 3-year period. In the intervention groups, in addition to the existing haemoglobin screening, ferritin was measured in all new donors and at every fifth donation in repeat donors. Subsequent donation intervals were extended to 6 months if ferritin concentrations were 15-30 ng/mL and to 12 months if they were less than 15 ng/mL. Outcomes were measured cross-sectionally across all donation centres at four timepoints. Primary outcomes were ferritin and haemoglobin concentrations, iron deficiency, and haemoglobin-based deferrals. We assessed all outcomes by sex and menopausal status and significance for primary outcomes was indicated by a p value of less than 0·0125. This trial is registered in the Dutch trial registry, NTR6738, and is complete.

FINDINGS

Between Sept 11, 2017, and Nov 27, 2020, 412 888 whole-blood donors visited a donation centre, and we did measurements on samples from 37 621 donations from 36 099 donors. Over 38 months, ferritin-guided donation intervals increased mean ferritin concentrations (by 0·18 log10 ng/mL [95% CI 0·15-0·22; p<0·0001] in male donors, 0·10 log10 ng/mL [0·06-0·15; p<0·0001] in premenopausal female donors, and 0·17 log10 ng/mL [0·12-0·21; p<0·0001] in postmenopausal female donors) and mean haemoglobin concentrations (by 0·30 g/dL [95% CI 0·22-0·38; p<0·0001] in male donors, 0·12 g/dL [0·03-0·20; p<0·0074] in premenopausal female donors, and 0·16 g/dL [0·05-0·27; p<0·0044] in postmenopausal female donors). Iron deficiency decreased by 36-38 months (odds ratio [OR] 0·24 [95% CI 0·18-0·31; p<0·0001] for male donors, 0·49 [0·37-0·64; p<0·0001] for premenopausal female donors, and 0·24 [0·15-0·37; p<0·0001] for postmenopausal female donors). At 36-38 months, haemoglobin-based deferral decreased significantly in male donors (OR at 36-38 months 0·21 [95% CI 0·10-0·40, p<0·0001]) but not significantly in premenopausal or postmenopausal female donors (0·81 [0·54-1·20; p=0·29] and 0·50 [95% CI 0·25-0·98; p=0·051], respectively).

INTERPRETATION

Ferritin-guided donation intervals significantly improved haemoglobin and ferritin concentrations and significantly decreased iron deficiency over the study period. Haemoglobin-based deferrals decreased significantly for male donors, but not female donors. Although this intervention is overall beneficial for maintenance of iron and haemoglobin concentrations in donors, increased efforts are needed to recruit and retain donors.

FUNDING

The Sanquin Research Programming Committee.

Measurement of lead, mercury, and cadmium in blood donors in Canada

BACKGROUND

Fetal and neonatal exposure to lead is associated with irreversible adverse effects on neural development. There is no reliable threshold for lead effect, so limiting exposure is recommended. A significant correlation has been reported between post-transfusion blood lead level (BLL) in infants and lead levels in transfused RBC units. We measured levels of lead, mercury, and cadmium, in Canadian donor blood to investigate if concerning levels for neonatal transfusion exist.

STUDY DESIGN AND METHODS

Whole blood samples from blood donors (n = 2529) were shipped cold within 7 days of donation. All permanent blood donation clinics across Canada were sampled. Twelve of these permanent clinics and 8 mobile clinics with a greater potential for having higher lead or mercury levels were oversampled. Heavy metals were measured by inductively coupled plasma mass spectrometry.

RESULTS

Of all donations, 2.2% (lead) and 0.4% (mercury) had levels higher than the recommended thresholds for safe neonatal transfusion. BLLs were higher in males but there was no significant difference in the blood mercury levels of males versus females. Cadmium levels were higher in females. There was a positive correlation between donor age and levels of heavy metals, with lead having the strongest correlation (r = 0.47, p < .0001). Three clinics in close proximity to two lead-producing mines were among the clinics with the highest BLLs. Significantly higher blood mercury levels were observed in coastal clinics.

CONCLUSION

Our data on donor blood heavy metal levels supports considering blood transfusion as an exposure source to heavy metals and encourages informed selection of blood units for transfusion to vulnerable groups.

Biological and Genetic Determinants of Glycolysis: Phosphofructokinase Isoforms Boost Energy Status of Stored Red Blood Cells and Transfusion Outcomes

Mature red blood cells (RBCs) lack mitochondria, and thus exclusively rely on glycolysis to generate adenosine triphosphate (ATP) during aging in vivo or storage in the blood bank. Here we leveraged 13,029 volunteers from the Recipient Epidemiology and Donor Evaluation Study to identify an association between end-of-storage levels of glycolytic metabolites and donor age, sex, and ancestry-specific genetic polymorphisms in regions encoding phosphofructokinase 1, platelet (detected in mature RBCs), hexokinase 1, ADP-ribosyl cyclase 1 and 2 (CD38/BST1). Gene-metabolite associations were validated in fresh and stored RBCs from 525 Diversity Outbred mice, and via multi-omics characterization of 1,929 samples from 643 human RBC units during storage. ATP and hypoxanthine levels - and the genetic traits linked to them - were associated with hemolysis in vitro and in vivo, both in healthy autologous transfusion recipients and in 5,816 critically ill patients receiving heterologous transfusions, suggesting their potential as markers to improve transfusion outcomes.

eTOC and Highlights

Highlights

Blood donor age and sex affect glycolysis in stored RBCs from 13,029 volunteers;Ancestry, genetic polymorphisms in PFKP, HK1, CD38/BST1 influence RBC glycolysis;Modeled PFKP effects relate to preventing loss of the total AXP pool in stored RBCs;ATP and hypoxanthine are biomarkers of hemolysis in vitro and in vivo.

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.

Appropriateness of inpatient intravenous iron therapy in a Swiss tertiary care hospital

INTRODUCTION

Intravenous (IV) iron replacement is an established treatment for iron deficiency and is recommended in various medical guidelines, but cheaper oral iron formulations remain first-line therapy in several instances. Data on adherence to current prescription standards are lacking in Switzerland.

METHODS

Retrospective single center quality control study evaluating the appropriateness of IV iron replacement in 400 inpatients during 2019 and 2021 at a Swiss tertiary care hospital. Appropriateness of IV iron was assessed by expert chart review according to national and international guidelines.

RESULTS

IV iron prescriptions were assessed as inappropriate in 147 (37%) of cases (indication lacking in 13%, oral route preferred in 24%). Inappropriate prescribing was more common (p < .001) in surgical wards (66%) compared to medical units (48%) and the gynecologic ward (19%). Iron studies were lacking in 29% of inappropriate IV administrations. Insufficient replacement dosages were chosen in 38% of patients with appropriate prescription.

CONCLUSION

Based on current guidelines, inappropriate in-hospital prescription of IV iron was frequently observed. Considerable differences exist between hospital units, which are consistent with conflicting recommendations of professional societies. We recommend increased attention toward the prescription quality to avoid unnecessary, expensive, and potentially harmful use of IV iron.

Restoration of metal homeostasis: a potential strategy against neurodegenerative diseases

Metal homeostasis is critical to normal neurophysiological activity. Metal ions are involved in the development, metabolism, redox and neurotransmitter transmission of the central nervous system (CNS). Thus, disturbance of homeostasis (such as metal deficiency or excess) can result in serious consequences, including neurooxidative stress, excitotoxicity, neuroinflammation, and nerve cell death. The uptake, transport and metabolism of metal ions are highly regulated by ion channels. There is growing evidence that metal ion disorders and/or the dysfunction of ion channels contribute to the progression of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS). Therefore, metal homeostasis-related signaling pathways are emerging as promising therapeutic targets for diverse neurological diseases. This review summarizes recent advances in the studies regarding the physiological and pathophysiological functions of metal ions and their channels, as well as their role in neurodegenerative diseases. In addition, currently available metal ion modulators and in vivo quantitative metal ion imaging methods are also discussed. Current work provides certain recommendations based on literatures and in-depth reflections to improve neurodegenerative diseases. Future studies should turn to crosstalk and interactions between different metal ions and their channels. Concomitant pharmacological interventions for two or more metal signaling pathways may offer clinical advantages in treating the neurodegenerative diseases.

Eligibility Considerations for Female Whole Blood Donors: Hemoglobin Levels and Iron Status in a Nationally Representative Population

Blood collection from minority populations improves the transfusion support of patients with sickle cell disease and thalassemia, but efforts are challenged by high deferral rates for hemoglobin (Hb) eligibility thresholds. This study sought to evaluate hemoglobin and iron status of a representative US female population to assess the suitability of 12.0 g/dL as minimum hemoglobin. Data were extracted from the National Health and Nutrition Examination Surveys (NHANES), 1999-2010. A national sample designed to reflect potential female blood donors (weight ≥110 lbs, not pregnant, no infectious marker reactivity, and no blood donation in past year) aged 16 to 49 years was analyzed for Hb and serum ferritin (SF) measures by race/ethnicity (N = 6937). Mean Hb and SF and the prevalence of iron deficiency ([ID] SF<12 ng/mL and SF<26 ng/mL) and low Hb (<12.5 g/dL and <12.0 g/dL) were estimated. Multivariable modified Poisson regression compared the prevalence for ID or low Hb at each cutoff by race/ethnicity. Mean SF values were higher and ID prevalence was lower in Non-Hispanic (NH) White (SF = 45.3 ng/mL, SF<12 ng/mL = 8.2%) than NH Black (SF = 39.6 ng/mL, SF<12 ng/mL = 14.2%) and Hispanic (SF = 36.5 ng/mL, SF<12 ng/mL = 12.7%) females. Compared to NH White females (13.7 g/dL), mean Hb was lower in NH Black (12.6 g/dL) and Hispanic females (13.4 g/dL). The percentage with Hb<12.5 g/dL was >4 times greater in NH Black (39.1%) and >2 times greater in Hispanic females (16.5%) compared to NH White (8.6%). Within 0.5 g/dL incremental categories of Hb, NH Black had higher mean SF levels and lower prevalence of SF<12 ng/mL or <26 ng/mL compared to NH White and Hispanic females. At Hb of 12.0 to 12.4g/dL, NH Black females had better measures of iron status (SF = 39.1 ng/mL, %SF<12 ng/mL = 12.0%) than NH White (SF = 33.6 ng/mL, %SF<12 ng/mL=15.8%) and Hispanic (SF = 30.4 ng/mL, %SF<12 ng/mL=15.5%) females whose Hb was 12.5 to 12.9 g/dL. Adjusting for age and Hb, the prevalence ratio for low SF was significantly lower in NH Black compared to NH White females at both SF<26 ng/mL (adjusted prevalence ratio [aPR] = 0.83, 95%CI = 0.76-0.92) and SF<12 ng/mL (aPR = 0.66, 95%CI = 0.52-0.83). NH Black females with Hb 12.0 to 12.4g/dL have better iron stores than NH White and Hispanic females whose Hb is 12.5 to 12.9 g/dL. The distribution of Hb and iron may support the safe collection of blood for female donors below the current Hb eligibility requirement of 12.5 g/dL.