Iron Chelator or Iron Supplement Consumption in COVID-19? The Role of Iron with Severity Infection

Iron is a trace element that is used to replicate the virus and has a role in the vital functions of the body and the host's innate immune system. The mechanism of iron in COVID-19 severity is still not well understood. The aim of this study was to evaluate the association of the iron with COVID-19 severity. A case-control study was performed on 147 patients with a positive PCR test result and 39 normal individuals admitted to the Persian Gulf Martyrs Hospital in Bushehr, Iran. The iron profiles and related tests were measured along with hematological analytes. Hemoglobin (Hb), Fe, and saturated transferrin decreased in all the groups compared to the controls, but ferritin increased in the patient groups. After adjusting for age and sex, we found that increased ferritin levels augmented the odds ratio (OR) of the disease in the moderate (OR = 2.95, P = 0.007), severe (OR = 6.1, P < 0.001), and critical groups (OR = 8.34, P < 0.001). The decreased levels of Fe reduced the OR of the disease in the mild (OR = 0.96, P < 0.001), moderate (OR = 0.96, P < 0.001), severe (OR = 0.95, P < 0.001), and critical (OR = 0.98, P = 0.001) groups. Fe (AUC = 85.95, cutoff < 75.5 µg/dL, P < 0.001) and ferritin (AUC = 84.45, cutoff > 157.5 ng/dL, P < 0.001) have higher AUC for disease prognosis, but only ferritin (AUC = 74.89, cutoff > 261.5 ng/dL, P < 0.001) has higher AUC for disease severity assays. It could be concluded that the use of iron chelators to reduce iron intake can be considered a therapeutic goal. In addition, measuring Fe and ferritin is beneficial for the diagnosis of the disease and determining its severity.

Cell-Free Hemoglobin in Acute Kidney Injury after Lung Transplantation and Experimental Renal Ischemia/Reperfusion

Cell-free hemoglobin (CFH), a pro-oxidant and cytotoxic compound that is released in hemolysis, has been associated with nephrotoxicity. Lung transplantation (LuTx) is a clinical condition with a high incidence of acute kidney injury (AKI). In this study, we investigated the plasma levels of CFH and haptoglobin, a CFH-binding serum protein, in prospectively enrolled LuTx patients (n = 20) with and without AKI. LuTx patients with postoperative AKI had higher CFH plasma levels at the end of surgery compared with no-AKI patients, and CFH correlated with serum creatinine at 48 h. Moreover, CFH levels inversely correlated with haptoglobin levels, which were significantly reduced at the end of surgery in LuTx patients with AKI. Because multiple other factors can contribute to AKI development in the complex clinical setting of LuTx, we next investigated the role of exogenous CFH administration in a mouse model of mild bilateral renal ischemia reperfusion injury (IRI). Exogenous administration of CFH after reperfusion caused overt AKI with creatinine increase, tubular injury, and enhanced markers of renal inflammation compared with vehicle-treated animals. In conclusion, CFH is a possible factor contributing to postoperative AKI after LuTx and promotes AKI in an experimental model of mild transient renal ischemia. Targeting CFH might be a therapeutic option to prevent AKI after LuTx.

Piperaquine-resistant PfCRT mutations differentially impact drug transport, hemoglobin catabolism and parasite physiology in Plasmodium falciparum asexual blood stages

The emergence of Plasmodium falciparum parasite resistance to dihydroartemisinin + piperaquine (PPQ) in Southeast Asia threatens plans to increase the global use of this first-line antimalarial combination. High-level PPQ resistance appears to be mediated primarily by novel mutations in the P. falciparum chloroquine resistance transporter (PfCRT), which enhance parasite survival at high PPQ concentrations in vitro and increase the risk of dihydroartemisinin + PPQ treatment failure in patients. Using isogenic Dd2 parasites expressing contemporary pfcrt alleles with differential in vitro PPQ susceptibilities, we herein characterize the molecular and physiological adaptations that define PPQ resistance in vitro. Using drug uptake and cellular heme fractionation assays we report that the F145I, M343L, and G353V PfCRT mutations differentially impact PPQ and chloroquine efflux. These mutations also modulate proteolytic degradation of host hemoglobin and the chemical inactivation of reactive heme species. Peptidomic analyses reveal significantly higher accumulation of putative hemoglobin-derived peptides in the PPQ-resistant mutant PfCRT isoforms compared to parental PPQ-sensitive Dd2. Joint transcriptomic and metabolomic profiling of late trophozoites from PPQ-resistant or -sensitive isogenic lines reveals differential expression of genes involved in protein translation and cellular metabolism. PPQ-resistant parasites also show increased susceptibility to an inhibitor of the P. falciparum M17 aminopeptidase that operates on short globin-derived peptides. These results reveal unique physiological changes caused by the gain of PPQ resistance and highlight the potential therapeutic value of targeting peptide metabolism in P. falciparum.

Iron Deficiency in Adolescent and Young Adult German Athletes-A Retrospective Study

Background: Iron deficiency is a common phenomenon in sports and may lead to impaired physical performance. The aim of the study was to determine the frequency of iron deficiency in competitive athletes and to discuss the resulting consequences. Methods: The data of 629 athletes (339 male, 290 female) who presented for their annual basic sports medicine examination were investigated. Depending on age (<14 years, 15−17 years, ≥18−30 years), four groups ((I.) normal hemoglobin (Hb) and ferritin level (≥30 ng/mL for adults and 15−18-year-olds; ≥20 ng/mL, respectively, ≥15 ng/mL for adolescents and children), (II.) prelatent iron deficiency (ID) (normal Hb, low ferritin), (III.) latent ID (additionally elevated soluble transferrin receptor or decreased transferrin saturation) and (IV.) manifest anemia) were distinguished. In addition, the iron status and exercise capacity of different types of sports were compared. Results: Overall we found an iron deficiency of 10.9% in male (mainly in adolescence) and 35.9% in female athletes (emphasized in adolescence and young adulthood). There were no significant differences in iron status in regard to the different sport types or in maximum performance for the different groups of iron deficiency. Conclusions: Adolescent and female athletes are more likely to have an iron deficiency. Therapy concepts for athletes therefore should pay attention to iron-rich diets.

Hemolysis, free hemoglobin toxicity, and scavenger protein therapeutics

During hemolysis, erythrophagocytes dispose damaged red blood cells. This prevents the extracellular release of hemoglobin, detoxifies heme, and recycles iron in a linked metabolic pathway. Complementary to this process, haptoglobin and hemopexin scavenge and shuttle the red blood cell toxins hemoglobin and heme to cellular clearance. Pathological hemolysis outpaces macrophage capacity and scavenger synthesis across a diversity of diseases. This imbalance leads to hemoglobin-driven disease progression. To meet a void in treatment options, scavenger protein-based therapeutics are in clinical development.

Impact of sublethal phenol in freshwater fish Labeo rohita on biochemical and haematological parameters

Phenol, an aromatic chemical commonly found in domestic and industrial effluents, upon its introduction into aquatic ecosystems adversely affects the indigenous biota, the invertebrates and the vertebrates. With the increased demand for agrochemicals, a large amount of phenol is released directly into the environment as a byproduct. Phenol and its derivatives tend to persist in the environment for longer periods which in turn poses a threat to both humans and the aquatic ecosystem. In our current study, the response of Labeo rohita to sublethal concentrations of phenol was observed and the results did show a regular decrease in biochemical constituents of the targeted organs. Exposure of Labeo rohita to sublethal concentration of phenol (22.32 mg/L) for an epoch of 7, 21 and 28 days shows a decline in lipid, protein, carbohydrate content and phosphatase activity in target organs such as the gills, muscle, intestine, liver and kidney of the fish. The present study also aims to investigate the toxic effects of phenol with special reference to the haematological parameters of Labeo rohita. At the end of the exposure period, the blood of the fish was collected by cutting the caudal peduncle with a surgical scalpel. And it was observed that the red blood corpuscle count (RBC), white blood corpuscle (WBC), haemoglobin count (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) values showed a decline after exposure to phenol for 7 days, while white blood corpuscle (WBC) shows an increased count. At 21 days and 28 days, all the haematological parameters showed a significant decrease.

Impact of dietary inclusion of Chenopodium quinoa on growth performance and survival of Hubbard chicken

The poultry sector is the most vibrant segment of the agriculture system plays a vital role in the supply of healthy meat products. Broiler production effectiveness is greatly associated with feed formulation. Although, broiler exhibits a relatively fast growth rate, the nutritional profile of its meat has been criticized under conventional human dietary regimes. In the current study, the dietary inclusion of quinoa was assessed to improve broiler growth performance, carcass quality, and health by analyzing different growth, hematological and biochemical, immunological parameters. In the present study, the chicken was fed with 50 g/kg, 100 g/kg, and 200 g/kg quinoa enriched diets in two different experimental groups during the growth phase or finisher phase while chicken fed with diet without quinoa were as control. The 50 g/kg quinoa supplemented chicken group revealed a substantial difference in growth performance in comparison with the control group. In addition, the examination of quinoa dietary supplementation on carcass quality exhibited variable behavior. Further, all the study groups fed with quinoa during the growth phase revealed no remarkable difference in the hematological profile in contrast to the control group except for the chicken group fed (50 g/Kg) during the finisher phase for hemoglobin levels. Likewise, all the quinoa enriched diet given chicken groups showed no significant difference in serum biochemical profile in contrast to the control group except for the 50 g/Kg quinoa fed chicken group during the finisher phase for total globulin levels. In addition, the examination of quinoa dietary supplementation on the broiler serum lipid profile was also assessed and birds exhibited variable behavior as the result of quinoa dietary supplementation. Evaluation of short-term immune response after quinoa supplementation assessed and birds exhibited no marked significance on expression outcomes of interleukin/cytokines (IL 1 beta, IL-6, IL-10) assessed by qRT-PCR analysis. In conclusion, the dietary supplementation of broiler fed with quinoa seeds can enhance the growth performance and the carcass quality of broiler.

Low grade intravascular hemolysis associates with peripheral nerve injury in type 2 diabetes

Type 2 diabetes (T2D) induces hyperglycemia, alters hemoglobin (Hb), red blood cell (RBC) deformability and impairs hemorheology. The question remains whether RBC breakdown and intravascular hemolysis (IVH) occur in T2D patients. We characterized RBC-degradation products and vesiculation in a case-control study of 109 T2D patients and 65 control subjects. We quantified heme-related absorbance by spectrophotometry and circulating extracellular vesicles (EV) by flow cytometry and electron microscopy. Heme-related absorbance was increased in T2D vs. control plasma (+57%) and further elevated in obese T2D plasma (+27%). However, large CD235a+ EV were not increased in T2D plasma. EV from T2D plasma, or shed by isolated T2D RBC, were notably smaller in diameter (-27%) and carried heme-related absorbance. In T2D plasma, higher heme-related absorbance (+30%) was associated to peripheral sensory neuropathy, and no other vascular complication. In vitro, T2D RBC-derived EV triggered endothelial stress and thrombin activation in a phosphatidylserine- and heme-dependent fashion. We concluded that T2D was associated with low-grade IVH. Plasma absorbance may constitute a novel biomarker of peripheral neuropathy in T2D, while flow cytometry focusing on large EV may be maladapted to characterize RBC EV in T2D. Moreover, therapeutics limiting IVH or neutralizing RBC breakdown products might bolster vasculoprotection in T2D.

Expression and Variations in EPAS1 Associated with Oxygen Metabolism in Sheep

Endothelial PAS domain protein 1 gene (EPAS1) is a member of the HIF gene family. This gene encodes a transcription factor subunit that is involved in the induction of oxygen-regulated genes. Several studies have demonstrated that a mutation in EPAS1 could affect oxygen sensing, polycythemia, and hemoglobin level. However, whether EPAS1 mutation affects sheep oxygen metabolism is still unknown. Therefore, we explored the relationship between the variation of EPAS1 and oxygen metabolism in sheep. In this study, variations in ovine EPAS1 exon 15 were investigated in 332 Tibetan sheep and 339 Hu sheep by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. In addition, we studied the effect of these variations on blood gas in 176 Tibetan sheep and 231 Hu sheep. Finally, the mRNA expression of EPAS1 in six tissues of Hu sheep and Tibetan sheep living at different altitudes (2500 m, 3500 m, and 4500 m) was analyzed by real-time quantitative PCR (RT-qPCR). Four alleles (A, B, C, and D) were detected, and their distributions highly differed between Tibetan sheep and Hu sheep. In Tibetan sheep, B was the dominant allele, and C and D alleles were rare, whereas all four alleles were common in Hu sheep. Six single nucleotide polymorphisms (SNPs) were identified between the four alleles and one of them was non-synonymous (p.F606L). While studying the blood gas levels in Tibetan sheep and Hu sheep, one variant region was found to be associated with an elevated pO₂ and sO₂, which suggested that variations in EPAS1 are associated with oxygen metabolism in sheep. RT-qPCR results showed that EPAS1 was expressed in the six tissues of Hu sheep and Tibetan sheep at different altitudes. In addition, the expression of EPAS1 in four tissues (heart, liver, spleen, and longissimus dorsi muscle) of Hu sheep was lower than that in Tibetan sheep from three different altitudes, and the expression of EPAS1 was positively correlated with the altitude. These results indicate that the variations and expression of EPAS1 is closely related to oxygen metabolism.

Haemoglobin transfusion threshold in traumatic brain injury optimisation (HEMOTION): a multicentre, randomised, clinical trial protocol

INTRODUCTION

Traumatic brain injury (TBI) is the leading cause of mortality and long-term disability in young adults. Despite the high prevalence of anaemia and red blood cell transfusion in patients with TBI, the optimal haemoglobin (Hb) transfusion threshold is unknown. We undertook a randomised trial to evaluate whether a liberal transfusion strategy improves clinical outcomes compared with a restrictive strategy.

METHODS AND ANALYSIS

HEMOglobin Transfusion Threshold in Traumatic Brain Injury OptimizatiON is an international pragmatic randomised open label blinded-endpoint clinical trial. We will include 742 adult patients admitted to an intensive care unit (ICU) with an acute moderate or severe blunt TBI (Glasgow Coma Scale ≤12) and a Hb level ≤100 g/L. Patients are randomly allocated using a 1:1 ratio, stratified by site, to a liberal (triggered by Hb ≤100 g/L) or a restrictive (triggered by Hb ≤70 g/L) transfusion strategy applied from the time of randomisation to the decision to withdraw life-sustaining therapies, ICU discharge or death. Primary and secondary outcomes are assessed centrally by trained research personnel blinded to the intervention. The primary outcome is the Glasgow Outcome Scale extended at 6 months. Secondary outcomes include overall functional independence measure, overall quality of life (EuroQoL 5-Dimension 5-Level; EQ-5D-5L), TBI-specific quality of life (Quality of Life after Brain Injury; QOLIBRI), depression (Patient Health Questionnaire; PHQ-9) and mortality.

ETHICS AND DISSEMINATION

This trial is approved by the CHU de Québec-Université Laval research ethics board (MP-20-2018-3706) and ethic boards at all participating sites. Our results will be published and shared with relevant organisations and healthcare professionals.

TRIAL REGISTRATION NUMBER

NCT03260478.

Mitigative Potential of Novel <i>Lactobacillus plantarum</i> TISTR 2076 against the Aflatoxins-Associated Oxidative Stress and Histopathological Alterations in Liver and Kidney of Broiler Chicks during the Entire Growth Period

Aflatoxins are the secondary metabolites produced by <i>Aspergillus flavus</i> and <i>Aspergillus parasiticus</i> and have severe pathological effects on the health of human and animals. The present study was designed to investigate the toxicopathological changes induced by aflatoxins and mitigative potential of <i>Lactobacillus plantarum</i> in broiler birds. One hundred and eighty broiler chicks at one day of age was procured from the local market, and chicks were equally divided into six groups with thirty birds in each group. These birds were treated with aflatoxins (300 and 600 µg/kg) and <i>Lactobacillus plantarum</i> (1 × 10⁸ cfu/kg of feed) in different combinations. The first group was kept as the control, and only a basal diet was provided to birds (BD). In the second group (AF1), the first level of aflatoxins (300 µg/kg) was fed to the birds. In the third group (AF2), the second level of aflatoxins (600 µg/kg) was fed to birds. In the fourth group (AF1LP), <i>Lactobacillus plantarum</i> was given with first level of aflatoxins. In the fifth group (AF2LP), <i>Lactobacillus plantarum</i> was given with the second level of aflatoxins, and in the 6th group (BDLP), <i>Lactobacillus plantarum</i> alone was fed to the chicks. This experimental study was continued for 42 days. Birds were slaughtered after 42 days, and different parameters were assessed. Parameters studied were gain in body weight, organ weight along with some histopathological, hematological, biochemical parameters and residues of aflatoxins in liver and kidney. <i>Lactobacillus plantarum</i> improved the body weight gain and restored the relative organ weight. Hepatic and renal biomarkers returned to normal concentrations, serum proteins were restored in combination group AF1LP, and partial amelioration was observed in the AF2LP group. Red blood cells, white blood cells, hemoglobin centration and packed cell volume became normalized in the AF1LP group, while partial amelioration was observed in the AF2LP group. LP also reduced the concentration of aflatoxin residues in liver kidney and improved the TAC concentrations. The results of this study elucidated the mitigative potential of <i>Lactobacillus plantarum</i> against serum biochemical, histopathological, hematological and toxicopathological changes induced by aflatoxins in the chicks.

Iron regulatory protein (IRP)-mediated iron homeostasis is critical for neutrophil development and differentiation in the bone marrow

Iron is mostly devoted to the hemoglobinization of erythrocytes for oxygen transport. However, emerging evidence points to a broader role for the metal in hematopoiesis, including the formation of the immune system. Iron availability in mammalian cells is controlled by iron-regulatory protein 1 (IRP1) and IRP2. We report that global disruption of both IRP1 and IRP2 in adult mice impairs neutrophil development and differentiation in the bone marrow, yielding immature neutrophils with abnormally high glycolytic and autophagic activity, resulting in neutropenia. IRPs promote neutrophil differentiation in a cell intrinsic manner by securing cellular iron supply together with transcriptional control of neutropoiesis to facilitate differentiation to fully mature neutrophils. Unlike neutrophils, monocyte count was not affected by IRP and iron deficiency, suggesting a lineage-specific effect of iron on myeloid output. This study unveils the previously unrecognized importance of IRPs and iron metabolism in the formation of a major branch of the innate immune system.

Prediction of Iron Deficiency Anemia in Third Trimester of Pregnancy Based on Data in the First Trimester: A Prospective Cohort Study in a High-Income Country

Background: Systematic iron supplementation may be harmful in pregnant women with non-depleted iron. Our objectives were to estimate the prevalence of anemia at the third trimester of pregnancy (T3) and to identify the parameters at the first trimester (T1), which best predict anemia at T3. Methods: This prospective cohort study in France included pregnant women at T1 without non-iron deficiency anemia. Clinical and social characteristics, health-related quality of life, blood count, and a frozen blood sample were collected at T1 and/or T3. Secondly, a matched nested case−control study was built for women with anemia at T3 but not at T1. Multivariate analyses and ROC curves were used to identify the best predictive parameter(s) of anemia at T3. Results: The prevalence of anemia at T3 in the cohort (629 women) was 21.9% (95% CI 18.7−25.2%). In the matched nested case−control study (256 women), hemoglobin (Hb), serum ferritin (SF) and the SF/soluble transferrin receptor ratio at T1 were predictive of anemia at T3 (p < 0.001); however, clinical and social characteristics, as serum hepcidin were not. In multivariate analyses, Hb at T1 was the best predictive biomarker of anemia at T3 with a cut-off value of 120 g/L (specificity 87.5%). Conclusions: The prevalence of anemia at the end of pregnancy remained high in a High-Income Country. Clinical, social, and biochemical parameters did not seem useful to predict anemia at T3 and could not guide iron supplementation. We suggest systematically performing a simple blood count in the first trimester of pregnancy and offering oral iron supplementation for women with Hb < 120 g/L.

Structure-Function Relationships of Oxygen Transport Proteins in Marine Invertebrates Enduring Higher Temperatures and Deoxygenation

AbstractPredictions for climate change-to lesser and greater extents-reveal a common scenario in which marine waters are characterized by a deadly trio of stressors: higher temperatures, lower oxygen levels, and acidification. Ectothermic taxa that inhabit coastal waters, such as shellfish, are vulnerable to rapid and prolonged environmental disturbances, such as heatwaves, pollution-induced eutrophication, and dysoxia. Oxygen transport capacity of the hemolymph (blood equivalent) is considered the proximal driver of thermotolerance and respiration in many invertebrates. Moreover, maintaining homeostasis under environmental duress is inextricably linked to the activities of the hemolymph-based oxygen transport or binding proteins. Several protein groups fulfill this role in marine invertebrates: copper-based extracellular hemocyanins, iron-based intracellular hemoglobins and hemerythrins, and giant extracellular hemoglobins. In this brief text, we revisit the distribution and multifunctional properties of oxygen transport proteins, notably hemocyanins, in the context of climate change, and the consequent physiological reprogramming of marine invertebrates.

Stealthy microbes: How Neisseria gonorrhoeae hijacks bulwarked iron during infection

Transition metals are essential for metalloprotein function among all domains of life. Humans utilize nutritional immunity to limit bacterial infections, employing metalloproteins such as hemoglobin, transferrin, and lactoferrin across a variety of physiological niches to sequester iron from invading bacteria. Consequently, some bacteria have evolved mechanisms to pirate the sequestered metals and thrive in these metal-restricted environments. Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection gonorrhea, causes devastating disease worldwide and is an example of a bacterium capable of circumventing human nutritional immunity. Via production of specific outer-membrane metallotransporters, N. gonorrhoeae is capable of extracting iron directly from human innate immunity metalloproteins. This review focuses on the function and expression of each metalloprotein at gonococcal infection sites, as well as what is known about how the gonococcus accesses bound iron.

Effects of Sports Functional Food on Physical Function of Athletes under Ultrasound Observation

In order to improve the physical function of athletes under hypoxic training, the authors propose to observe the effect of functional food with active ingredients of polypeptide polyamines in deer antler on the physical function of athletes under ultrasound observation. According to the characteristics of physiological changes during hypoxic training, functional foods containing the active ingredients of polypeptide polyamines in deer antler were selected and given to athletes under simulated hypoxic training, observe the changes of red blood cells (RBC), hemoglobin (Hb), hematocrit (Hct), blood lactic acid, free radical metabolism and immune function of athletes, and musculoskeletal under ultrasound observation, discuss how to improve the physical function and athletic ability of athletes under hypoxic training. Experimental results show that athletes after 6 weeks of hypoxic training, red blood cells and hemoglobin were significantly increased, there was a significant difference compared to the control group (P < 0.05 or P < 0.01). After 6 weeks of hypoxic training, hemoglobin increased by 10.1%, a 5.6 percentage point increase compared to the control group. Conclusion. The antler peptides used by the authors can enhance the effect of hypoxic training.

Haematological actions of androgens

In this review, we discuss the effects on androgens on the haemopoietic system, focussing largely on the effects of testosterone on erythropoiesis. Stimulation of erythropoiesis is one of the most consistent effects of testosterone treatment observed in clinical trials. In men with anaemia this effect can be beneficial. Conversely, erythrocytosis is one of the most common adverse effects of testosterone treatment with a relative risk of 8.14 (95% CI: 1.87-35.40) estimated by a recent meta-analysis of randomised placebo controlled clinical trials. A reduction in haemoglobin is commonly seen in men receiving androgen deprivation therapy for prostate cancer, and in transwomen receiving gender affirming therapy to reduce serum testosterone. While mechanisms by which androgens regulate erythropoiesis are not fully understood, it is likely that effects on erythropoietic progenitor cells and erythropoietin are involved, with secondary effects on iron metabolism. In contrast, whether androgens exert clinically relevant effects on white blood cells and on platelets requires further study.

Erythropoietic effects of vadadustat in patients with anemia associated with chronic kidney disease

Patients with chronic kidney disease (CKD) develop anemia largely because of inappropriately low erythropoietin (EPO) production and insufficient iron available to erythroid precursors. In four phase 3, randomized, open-label, clinical trials in dialysis-dependent and non-dialysis-dependent patients with CKD and anemia, the hypoxia-inducible factor prolyl hydroxylase inhibitor, vadadustat, was noninferior to the erythropoiesis-stimulating agent, darbepoetin alfa, in increasing and maintaining target hemoglobin concentrations. In these trials, vadadustat increased the concentrations of serum EPO, the numbers of circulating erythrocytes, and the numbers of circulating reticulocytes. Achieved hemoglobin concentrations were similar in patients treated with either vadadustat or darbepoetin alfa, but compared with patients receiving darbepoetin alfa, those receiving vadadustat had erythrocytes with increased mean corpuscular volume and mean corpuscular hemoglobin, while the red cell distribution width was decreased. Increased serum transferrin concentrations, as measured by total iron-binding capacity, combined with stable serum iron concentrations, resulted in decreased transferrin saturation in patients randomized to vadadustat compared with patients randomized to darbepoetin alfa. The decreases in transferrin saturation were associated with relatively greater declines in serum hepcidin and ferritin in patients receiving vadadustat compared with those receiving darbepoetin alfa. These results for serum transferrin saturation, hepcidin, ferritin, and erythrocyte indices were consistent with improved iron availability in the patients receiving vadadustat. Thus, overall, vadadustat had beneficial effects on three aspects of erythropoiesis in patients with anemia associated with CKD: increased endogenous EPO production, improved iron availability to erythroid cells, and increased reticulocytes in the circulation.

Sickle cell anaemia and severe Plasmodium falciparum malaria: a secondary analysis of the Transfusion and Treatment of African Children Trial (TRACT)

BACKGROUND

Sickle cell anaemia (SCA) has historically been associated with high levels of childhood mortality in Africa. Although malaria has a major contribution to this mortality, to date, the clinical pathology of malaria among children with SCA has been poorly described. We aimed to explore the relationship between SCA and Plasmodium falciparum malaria in further detail by investigating the burden and severity of malaria infections among children recruited with severe anaemia to the TRACT trial of blood transfusion in Africa.

METHODS

This study is a post-hoc secondary analysis of the TRACT trial data, conducted after trial completion. TRACT was an open-label, multicentre, factorial, randomised controlled trial enrolling children aged 2 months to 12 years who presented with severe anaemia (haemoglobin <6·0 g/dL) to four hospitals in Africa. This secondary analysis is restricted to Uganda, where the birth prevalence of SCA is approximately 1% and malaria transmission is high. Children were classified as normal (HbAA), heterozygous (HbAS), or homozygous (HbSS; SCA) for the rs334 A→T sickle mutation in HBB following batch-genotyping by PCR at the end of the trial. To avoid confounding from SCA-specific medical interventions, we considered children with an existing diagnosis of SCA (known SCA) separately from those diagnosed at the end of the trial (unknown SCA). The outcomes considered in this secondary analysis were measures of P falciparum parasite burden, features of severe malaria, and mortality at day 28 in malaria-positive children.

FINDINGS

Between Sept 17, 2014, and May 15, 2017, 3944 children with severe anaemia were enrolled into the TRACT trial. 3483 children from Uganda were considered in this secondary analysis. Overall, 1038 (30%) of 3483 Ugandan children had SCA. 1815 (78%) of 2321 children without SCA (HbAA) tested positive for P falciparum malaria, whereas the prevalence was significantly lower in children with SCA (347 [33%] of 1038; p<0·0001). Concentrations of plasma P falciparum histidine-rich protein 2 (PfHRP2), a marker of the total burden of malaria parasites within an individual, were significantly lower in children with either known SCA (median 8 ng/mL; IQR 0-57) or unknown SCA (7 ng/mL; 0-50) than in HbAA children (346 ng/mL; 21-2121; p<0·0001). In contrast to HbAA children, few HbSS children presented with classic features of severe and complicated malaria, but both the frequency and severity of anaemia were higher in HbSS children. We found no evidence for increased mortality at day 28 in those with SCA compared with those without SCA overall (hazard ratios 1·07 [95% CI 0·31-3·76] for known SCA and 0·67 [0·15-2·90] for unknown SCA).

INTERPRETATION

The current study suggests that children with SCA are innately protected against classic severe malaria. However, it also shows that even low-level infections can precipitate severe anaemic crises that would likely prove fatal without rapid access to blood transfusion services.

FUNDING

UK Medical Research Council, Wellcome, and UK National Institute for Health and Care Research.

Antioxidant enzyme activity and pathophysiological responses in the freshwater walking catfish, Clarias batrachus Linn under sub-chronic and chronic exposures to the neonicotinoid, Thiamethoxam®

The hydrophilic nature and resultant persistence of neonicotinoids in aquatic systems increase the exposure duration for non-target organisms. The sublethal toxicity of the neonicotinoid Thiamethoxam® spanning sub-chronic and chronic durations was investigated in Clarias batrachus, a non-target freshwater fish species. 96 h LC₅₀ value of Thiamethoxam® on Clarias batrachus was 138.60 mg L^-1. Pre-determined exposure concentrations of Thiamethoxam® (6.93 and 13.86 mg L^-1) were used and effects were assessed at days 15, 30, and 45 exposure intervals. Biomarker effects were evaluated using antioxidant enzyme responses (CAT, SOD) neurotransmission (acetylcholinesterase activity), haematological and serum biochemistry changes (including haemoglobin content, total erythrocyte count, and serum albumin total leukocyte count, total serum protein, serum globulin, triglyceride, cholesterol, high-density lipoprotein, very low-density lipoprotein, low-density lipoprotein, phospholipid, and total serum glucose), histopathological alterations (gill and liver). Thiamethoxam®-exposed fish showed a marked reduction in haemoglobin content, total erythrocyte count, and serum albumin levels compared to control fish. Similarly, gill and liver antioxidant enzyme activity (CAT, SOD) and neurotransmission (acetylcholinesterase) also showed altered responses between sub-chronic exposure on day-15 and chronic responses on day-45. Histopathological observations in gill tissue revealed alterations ranging from vacuolation, hypertrophy, disruption of primary lamellar architecture, haemorrhage, the fusion of secondary lamella, and sloughing of outer epithelia. For liver tissue of exposed fish histopathological observations included increased sinusoidal spaces (ISS), necrosis of hepatocytes (NOH), nuclear degeneration (ND), disruption of architecture (DOA), macrophage infiltration of the central vein, vacuolation (V), hypertrophied hepatocytes, and haemorrhages. The gradients of toxic responses across exposure concentrations and depictions of impaired fish health with increasing thiamethoxam® exposure duration portend lowered physiological capacity for survival in the wild.

Effects of a Novel Amino Acid Formula on Nutritional and Metabolic Status, Anemia and Myocardial Function in Thrice-Weekly Hemodialysis Patients: Results of a Six-Month Randomized Double-Blind Placebo-Controlled Pilot Study

(1) Background: Chronic Kidney Disease (CKD) induces metabolic derangement of amino acid (AA) kinetics, eliciting severe damage to the protein anabolism. This damage is further intensified by a significant loss of AAs through hemodialysis (HD), affecting all tissues with a high metabolic turnover, such as the myocardium and body muscle mass. (2) Aim: to illustrate the effects of a novel AA mixture in boosting mitochondrial energy production. (3) Methods: A strict selection of 164 dialysis patients was carried out, allowing us to finally identify 22 compliant patients who had not used any form of supplements over the previous year. The study design envisaged a 6-month randomized, double-blind trial for the comparison of two groups of hemodialysis patients: eleven patients (67.2 ± 9.5 years) received the novel AA mix (TRG), whilst the other eleven (68.2 ± 10.5 years) were given a placebo mix that was indistinguishable from the treatment mix (PLG). (4) Results: Despite the 6-month observation period, the following were observed: maintenance of target hemoglobin values with a reduced need for erythropoiesis-stimulating agents in TRG > 36% compared to PLG (p < 0.02), improved phase angle (PhA) accompanied by an increase in muscle mass solely in the TRG group (p < 0.05), improved Left Ventricular Ejection Fraction (LVEF > 67%) in the TRG versus PLG group (p < 0.05) with early but marked signs of improved diastolic function. Increased sensitivity to insulin with greater control of glycemic levels in TRG versus PLG (p = 0.016). (5) Conclusions: the new AA mix seemed to be effective, showing a positive result on nutritional metabolism and cardiac performance, stable hemoglobin levels with the need for lower doses of erythropoietin (EPO), insulin increased cell sensitivity, better muscle metabolism with less loss of mass.

Physiological and Pathological Functions of Neuronal Hemoglobin: A Key Underappreciated Protein in Parkinson's Disease

The expression of Hemoglobin (Hb) is not restricted to erythrocytes but is also present in neurons. Hb is selectively enriched in vulnerable mesencephalic dopaminergic neurons of Parkinson's disease (PD) instead of resistant neurons. Controversial results of neuronal Hb levels have been reported in postmortem brains of PD patients: although neuronal Hb levels may decline in PD patients, elderly men with higher Hb levels have an increased risk of developing PD. α-synuclein, a key protein involved in PD pathology, interacts directly with Hb protein and forms complexes in erythrocytes and brains of monkeys and humans. These complexes increase in erythrocytes and striatal cytoplasm, while they decrease in striatal mitochondria with aging. Besides, the colocalization of serine 129-phosphorylated (Pser129) α-synuclein and Hb β chains have been found in the brains of PD patients. Several underlying molecular mechanisms involving mitochondrial homeostasis, α-synuclein accumulation, iron metabolism, and hormone-regulated signaling pathways have been investigated to assess the relationship between neuronal Hb and PD development. The formation of fibrils with neuronal Hb in various neurodegenerative diseases may indicate a common fibrillization pathway and a widespread target that could be applied in neurodegeneration therapy.

Multimodal Noninvasive Functional Neurophotonic Imaging of Murine Brain-Wide Sensory Responses

Modern optical neuroimaging approaches are expanding the ability to elucidate complex brain function. Diverse imaging contrasts enable direct observation of neural activity with functional sensors along with the induced hemodynamic responses. To date, decoupling the complex interplay of neurovascular coupling and dynamical physiological states has remained challenging when employing single-modality functional neuroimaging readings. A hybrid fluorescence optoacoustic tomography platform combined with a custom data processing pipeline based on statistical parametric mapping is devised, attaining the first noninvasive observation of simultaneous calcium and hemodynamic activation patterns using optical contrasts. Correlated changes in the oxy- and deoxygenated hemoglobin, total hemoglobin, oxygen saturation, and rapid GCaMP6f fluorescence signals are observed in response to peripheral sensory stimulation. While the concurrent epifluorescence serves to corroborate and complement the functional optoacoustic observations, the latter further aids in decoupling the rapid calcium responses from the slowly varying background in the fluorescence recordings mediated by hemodynamic changes. The hybrid imaging platform expands the capabilities of conventional neuroimaging methods to provide more comprehensive functional readings for studying neurovascular and neurometabolic coupling mechanisms and related diseases.

Quercetin as an inhibitor of hemoglobin-mediated lipid oxidation: Mechanisms of action and use of molecular docking

The antioxidant effect of quercetin on hemoglobin(Hb)-mediated lipid oxidation and the mechanisms involved were investigated. Quercetin strongly inhibited Hb-mediated lipid oxidation in washed muscle. Quercetin showed effective hydroxyl radical scavenging ability similar to butylated hydroxytoluene (BHT). Quercetin reduced metHb resulting in formation of oxyHb. Bound quercetin decreased heme dissociation from metHb. Conversion to oxyHb and decreased heme dissociation represent routes to limit Hb-mediated lipid oxidation. Electrospray ionization mass spectrometry (ESI-MS) indicated one molecule of quercetin was covalently bound to Hb α-chain. Quercetin quinone docked 3.3 Å from the thiol of αCys(H15) but not near any other Cys residues of turkey Hb. At the docking site, hydrogen bonding between quercetin quinone and amino acids of α- and β-chain was demonstrated. This represents a path by which quercetin became covalently bound to α-chain. Molecular docking of heme proteins to polyphenols provides a template to better understand antioxidant interactions in muscle foods.

Single Leg Cycling Offsets Reduced Muscle Oxygenation in Hypoxic Environments

The intensity of large muscle mass exercise declines at altitude due to reduced oxygen delivery to active muscles. The purpose of this investigation was to determine if the greater limb blood flow during single-leg cycling prevents the reduction in tissue oxygenation observed during traditional double-leg cycling in hypoxic conditions. Ten healthy individuals performed bouts of double and single-leg cycling (4, four-minute stages at 50−80% of their peak oxygen consumption) in hypoxic (15% inspired O2) and normoxic conditions. Heart rate, mean arterial pressure, femoral blood flow, lactate, oxygenated hemoglobin, total hemoglobin, and tissue saturation index in the vastus lateralis were recorded during cycling tests. Femoral blood flow (2846 ± 912 mL/min) and oxygenated hemoglobin (−2.98 ± 3.56 au) during single-leg cycling in hypoxia were greater than double-leg cycling in hypoxia (2429 ± 835 mL/min and −6.78 ± 3.22 au respectively, p ≤ 0.01). In addition, tissue saturation index was also reduced in the double-leg hypoxic condition (60.2 ± 3.1%) compared to double-leg normoxic (66.0 ± 2.4%, p = 0.008) and single-leg hypoxic (63.3 ± 3.2, p < 0.001) conditions. These data indicate that while at altitude, use of reduced muscle mass exercise can help offset the reduction in tissue oxygenation observed during larger muscle mass activities allowing athletes to exercise at greater limb/muscle specific intensities.

Adequacy of an Altitude Fitness Program (Living and Training) plus Intermittent Exposure to Hypoxia for Improving Hematological Biomarkers and Sports Performance of Elite Athletes: A Single-Blind Randomized Clinical Trial

Athletes incorporate altitude training programs into their conventional training to improve their performance. The purpose of this study was to determine the effects of an 8-week altitude training program that was supplemented with intermittent hypoxic training (IHE) on the blood biomarkers, sports performance, and safety profiles of elite athletes. In a single-blind randomized clinical trial that followed the CONSORT recommendations, 24 male athletes were randomized to an IHE group (HA, n = 12) or an intermittent normoxia group (NA, n = 12). The IHE consisted of 5-min cycles of hypoxia−normoxia with an FIO2 of between 10−13% for 90 min every day for 8 weeks. Hematological (red blood cells, hemoglobin, hematocrit, hematocrit, reticulated hemoglobin, reticulocytes, and erythropoietin), immunological (leukocytes, monocytes, and lymphocytes), and renal (urea, creatinine, glomerular filtrate, and total protein) biomarkers were assessed at the baseline (T1), day 28 (T2), and day 56 (T3). Sports performance was evaluated at T1 and T3 by measuring quadriceps strength and using three-time trials over the distances of 60, 400, and 1000 m on an athletics track. Statistically significant increases (p < 0.05) in erythropoietin, reticulocytes, hemoglobin, and reticulocyte hemoglobin were observed in the HA group at T3 with respect to T1 and the NA group. In addition, statistically significant improvements (p < 0.05) were achieved in all performance tests. No variations were observed in the immunological or renal biomarkers. The athletes who were living and training at 1065 m and were supplemented with IHE produced significant improvements in their hematological behavior and sports performance with optimal safety profiles.

Associations of Hemoglobin Adducts of Acrylamide and Glycidamide with Prevalent Metabolic Syndrome in a Nationwide Population-Based Study

Environmental and dietary exposures to acrylamide (AA) have been linked with various metabolic-related outcomes, but the results are mixed. However, the association between long-term exposure to AA and the prevalence of metabolic syndrome (MetS) remains unknown. In this study, we aimed to assess the relationship between hemoglobin adducts of AA, biomarkers of internal exposure to AA, and MetS prevalence among a U.S. nationwide population. MetS patients were defined by meeting three or more of the following five characteristics: elevated blood pressure, high fasting glucose, abdominal obesity, hypertriglyceridemia, and lower high-density lipoprotein cholesterol (HDL-C). Multivariate-adjusted logistic regression models and restricted cubic spline models were used to analyze the associations between AA hemoglobin biomarkers and MetS prevalence. A total of 1552 MetS cases were documented. After adjustment for the potential confounders, the odds ratios (95% confidence intervals) of MetS prevalence in the highest quartile of AA hemoglobin biomarkers were 0.60 (0.40-0.89), 1.26 (0.84-1.89), 0.93 (0.71-1.21), and 1.61 (1.18-2.20) for HbAA, HbGA, the sum of HbAA and HbGA (HbAA + HbGA), and the ratio of HbGA to HbAA (HbGA/HbAA), compared with the lowest quartile, respectively. HbAA was significantly and inversely associated with blood pressure, fasting glucose, abdominal obesity, hypertriglyceridemia, and low HDL-C, while the HbGA/HbAA ratio was also positively associated with abdominal obesity, hypertriglyceridemia, and low HDL-C. The restricted cubic spline models revealed a positive relationship between the HbGA/HbAA ratio and the prevalence of MetS, while the HbAA level was inversely associated with MetS prevalence. Our current findings provided epidemiological evidence that HbAA and the HbGA/HbAA ratio were significantly associated with MetS prevalence among general U.S. adults. Further studies should be conducted to examine the association between internal exposure to AA and MetS prevalence.

Associations of bacterial enteropathogens with systemic inflammation, iron deficiency, and anemia in preschool-age children in southern Ghana

Anemia remains a pervasive public health problem among preschool-age children in Ghana. Recent analyses have found that anemia in Ghanaian children, particularly in Southern regions, is largely attributable to infectious causes, rather than nutritional factors. Infections with enteropathogens can reduce iron absorption and increase systemic inflammation, but few studies have examined direct links between enteropathogens and anemia. This study investigated associations between detection of individual bacterial enteropathogens and systemic inflammation, iron deficiency, and anemia among 6- to 59-month-old children in Greater Accra, Ghana. Serum samples were analyzed from a cross-sectional sample of 262 children for concentrations of hemoglobin (Hb), biomarkers of systemic inflammation [C-reactive protein (CRP) and α-1-acid glycoprotein (AGP)], and biomarkers of iron status [serum ferritin (SF) and serum transferrin receptor (sTfR)]. Stool samples were analyzed for ten bacterial enteropathogens using qPCR. We estimated associations between presence of each enteropathogen and elevated systemic inflammation (CRP > 5 mg/L and AGP > 1 g/L), iron deficiency (SF < 12 μg/L and sTfR > 8.3 mg/L) and anemia (Hb < 110 g/L). Enteropathogens were detected in 87% of children’s stool despite a low prevalence of diarrhea (6.5%). Almost half (46%) of children had anemia while one-quarter (24%) had iron deficiency (low SF). Despite finding no associations with illness symptoms, Campylobacter jejuni/coli detection was strongly associated with elevated CRP [Odds Ratio (95% CI): 3.49 (1.45, 8.41)] and elevated AGP [4.27 (1.85, 9.84)]. Of the pathogens examined, only enteroinvasive Escherichia coli/Shigella spp. (EIEC/Shigella) was associated with iron deficiency, and enteroaggregative Escherichia coli (EAEC) [1.69 (1.01, 2.84)] and EIEC/Shigella [2.34 (1.15, 4.76)] were associated with anemia. These results suggest that certain enteroinvasive pathogenic bacteria may contribute to child anemia. Reducing exposure to enteropathogens through improved water, sanitation, and hygiene practices may help reduce the burden of anemia in young Ghanaian children.

Mechanisms of Blood pH Changes in Venovenous Extracorporeal Membrane Systems: Roles of Hemoglobin-Ion Binding and Donnan Equilibrium

An equilibrium model was developed to understand interrelated, physicochemical mechanisms leading to blood pH and electrolyte distribution changes in patients because of venovenous extracorporeal membrane oxygenation (ECMO) and carbon dioxide removal. The model consists of plasma and red cell compartments between which water and small ions can move to establish an equilibrium state. Governing forces are as follows: 1) ionic electroneutrality in each compartment; 2) osmotic equilibrium between compartments; 3) mass balance of small ions other than bicarbonate; 4) oxygen (O 2 )-dependent hemoglobin (Hb)-Cl binding in red cells; 5) albumin binding to Cl - , Ca 2+ , and Mg 2+ in plasma; and 6) chemical equilibria of carbonates and phosphates in each compartment. The model was constructed and validated using recent clinical ECMO inlet and exit blood-pH and electrolyte concentration data. The model closely described pH and electrolyte concentration changes in both states, which validated the model. The model was then used to predict CO 2 and O 2 saturation-induced changes in pH and electrolyte concentrations. It was found that O 2 -dependent Hb-Cl binding had a much lesser effect on blood acid-base status changes and electrolyte shifts during ECMO than previously thought. The model showed that the Cl-shift and Gibbs-Donnan equilibrium effects, characterized by pH and electrolyte distribution changes during ECMO, were primarily caused by changes in pH-induced electrical charge on mainly Hb and other constrained ions in red cells. These insights can improve understanding of the same factors acting when blood traverses the lung.

Effect of angiotensin-converting enzyme inhibition on cardiovascular adaptation to exercise training

Angiotensin-converting enzyme (ACE) activity may be one determinant of adaptability to exercise training, but well-controlled studies in humans without confounding conditions are lacking. Thus, the purpose of the present study was to investigate whether ACE inhibition affects cardiovascular adaptations to exercise training in healthy humans. Healthy participants of both genders (40 ± 7 years) completed a randomized, double-blind, placebo-controlled trial. Eight weeks of exercise training combined with placebo (PLA, n = 25) or ACE inhibitor (ACEi, n = 23) treatment was carried out. Before and after the intervention, cardiovascular characteristics were investigated. Mean arterial blood pressure was reduced (p < 0.001) by -5.5 [-8.4; -2.6] mmHg in ACEi , whereas the 0.7 [-2.0; 3.5] mmHg fluctuation in PLA was non-significant. Maximal oxygen uptake increased (p < 0.001) irrespective of ACE inhibitor treatment by 13 [8; 17] % in ACEi and 13 [9; 17] % in PLA. In addition, skeletal muscle endurance increased (p < 0.001) to a similar extent in both groups, with magnitudes of 82 [55; 113] % in ACEi and 74 [48; 105] % in PLA. In contrast, left atrial volume decreased (p < 0.05) by -9 [-16; -2] % in ACEi , but increased (p < 0.01) by 14 [5; 23] % in PLA. Total hemoglobin mass was reduced (p < 0.01) by -3 [-6; -1] % in ACEi , while a non-significant numeric increase of 2 [-0.4; 4] % existed in PLA. The lean mass remained constant in ACEi but increased (p < 0.001) by 3 [2; 4] % in PLA. In healthy middle-aged adults, 8 weeks of high-intensity exercise training increases maximal oxygen uptake and skeletal muscle endurance irrespective of ACE inhibitor treatment. However, ACE inhibitor treatment counteracts exercise training-induced increases in lean mass and left atrial volume. ACE inhibitor treatment compromises total hemoglobin mass.

The Immunological Effect of Oxygen Carriers on Normothermic Ex Vivo Liver Perfusion

Introduction

Normothermic ex vivo liver perfusion (NEVLP) is an organ preservation method that allows liver graft functional assessment prior to transplantation. One key component of normothermic perfusion solution is an oxygen carrier to provide oxygen to the liver to sustain metabolic activities. Oxygen carriers such as red blood cells (RBCs) or hemoglobin-based oxygen carriers have an unknown effect on the liver-resident immune cells during NEVLP. In this study, we assessed the effects of different oxygen carriers on the phenotype and function of liver-resident immune cells.

Methods

Adult Lewis rat livers underwent NEVLP using three different oxygen carriers: human packed RBCs (pRBCs), rat pRBCs, or Oxyglobin (a synthetic hemoglobin-based oxygen carrier). Hourly perfusate samples were collected for downstream analysis, and livers were digested to isolate immune cells. The concentration of common cytokines was measured in the perfusate, and the immune cells underwent phenotypic characterization with flow cytometry and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The stimulatory function of the liver-resident immune cells was assessed using mixed lymphocyte reactions.

Results

There were no differences in liver function, liver damage, or histology between the three oxygen carriers. qRT-PCR revealed that the gene expression of nuclear factor κ light chain enhancer of activated B cells (NF-kB), Interleukin (IL-1β), C-C motif chemokine ligand 2 (CCL2), C-C motif chemokine ligand 7 (CCL7), and CD14 was significantly upregulated in the human pRBC group compared with that in the naive, whereas the rat pRBC and Oxyglobin groups were not different from that of naive. Flow cytometry demonstrated that the cell surface expression of the immune co-stimulatory protein, CD86, was significantly higher on liver-resident macrophages and plasmacytoid dendritic cells perfused with human pRBC compared to Oxyglobin. Mixed lymphocyte reactions revealed increased allogeneic T-cell proliferation in the human and rat pRBC groups compared to that in the Oxyglobin group.

Conclusions

Liver-resident immune cells are important mediators of rejection after transplantation. In this study, we show that the oxygen carrier used in NEVLP solutions can affect the phenotype of these liver-resident immune cells. The synthetic hemoglobin-based oxygen carrier, Oxyglobin, showed the least amount of liver-resident immune cell activation and the least amount of allogeneic proliferation when compared to human or rat pRBCs. To mitigate liver-resident immune cell activation during NEVLP (and subsequent transplantation), Oxyglobin may be an optimal oxygen carrier.

HupZ, a Unique Heme-Binding Protein, Enhances Group A Streptococcus Fitness During Mucosal Colonization

Group A Streptococcus (GAS) is a major pathogen that causes simple and invasive infections. GAS requires iron for metabolic processes and pathogenesis, and heme is its preferred iron source. We previously described the iron-regulated hupZ in GAS, showing that a recombinant HupZ-His₆ protein binds and degrades heme. The His₆ tag was later implicated in heme iron coordination by HupZ-His₆. Hence, we tested several recombinant HupZ proteins, including a tag-free protein, for heme binding and degradation in vitro. We established that HupZ binds heme but without coordinating the heme iron. Heme-HupZ readily accepted exogenous imidazole as its axial heme ligand, prompting degradation. Furthermore, HupZ bound a fragment of heme c (whose iron is coordinated by the cytochrome histidine residue) and exhibited limited degradation. GAS, however, did not grow on a heme c fragment as an iron source. Heterologous HupZ expression in Lactococcus lactis increased heme b iron use. A GAS hupZ mutant showed reduced growth when using hemoglobin as an iron source, increased sensitivity to heme toxicity, and decreased fitness in a murine model for vaginal colonization. Together, the data demonstrate that HupZ contributes to heme metabolism and host survival, likely as a heme chaperone. HupZ is structurally similar to the recently described heme c-degrading enzyme, Pden_1323, suggesting that the GAS HupZ might be divergent to play a new role in heme metabolism.

Iron status and inflammation in women of reproductive age: A population-based biomarker survey and clinical study

BACKGROUND

Women of reproductive age (WRA) are at increased risk for anemia and iron deficiency. However, there is limited population-level data in India, which could help inform evidence-based recommendations and policy.

AIMS

To conduct a population-based biomarker survey of anemia, iron deficiency, and inflammation in WRA in Southern India.

METHODS

Participants were WRA (15-40 y) who were not pregnant or lactating. Blood samples (n = 979) were collected and analyzed for hemoglobin (Hb), serum ferritin (SF), soluble transferrin receptor (sTfR), C-reactive protein (CRP), and alpha-1 acid glycoprotein (AGP). Anemia and severe anemia were defined as Hb < 12.0 and < 8.0 g/dL. Serum ferritin was adjusted for inflammation using BRINDA methods. Iron deficiency was defined as SF <15.0 μg/L, iron insufficiency was defined as SF < 20.0 and < 25.0 μg/L, and iron deficiency anemia was defined as Hb < 12.0 g/dL and SF < 15.0 μg/L. Inflammation was defined as CRP > 5.0 mg/L or AGP > 1.0 g/L. Restricted cubic spline regression models were also used to determine if alternative SF thresholds should be used t to classify iron deficiency.

RESULTS

A total of 41.5% of WRA had anemia, and 3.0% had severe anemia. Findings from spline analyses suggested a SF cut-off of < 15.0 μg/L, consistent with conventional cut-offs for iron deficiency. 46.3% of WRA had SF < 15.0 μg/L (BRINDA-adjusted: 61.5%), 55.0% had SF < 20.0 μg/L (72.7%), 61.8% had SF < 25.0 μg/L (81.0%), and 30.0% had IDA (34.5%). 17.3% of WRA had CRP > 5.0 mg/L and 22.2% had AGP > 1.0 g/L. The prevalence of ID (rural vs. urban: 49.1% vs. 34.9%; p = 0.0004), iron insufficiency (57.8% vs. 43.8%; p = 0.0005), and IDA (31.8% vs. 22.4%; p = 0.01) were significantly higher in rural areas, although CRP levels were lower and there were no differences in elevated CRP or AGP.

CONCLUSIONS

The burden of anemia and iron deficiency in this population was substantial, and increased after adjusting for inflammation, suggesting potential to benefit from screening and interventions.

REGISTRATION NUMBER

NCT04048330.

Regulation and Role of Neuron-Derived Hemoglobin in the Mouse Hippocampus

Hemoglobin (Hb) is the oxygen transport protein in erythrocytes. In blood, Hb is a tetramer consisting of two Hb-alpha (Hb-α) chains and two Hb-beta (Hb-β) chains. A number of studies have also shown that Hb-α is also expressed in neurons in both the rodent and human brain. In the current study, we examined for age-related regulation of neuronal Hb-α and hypoxia in the hippocampus and cerebral cortex of intact male and female mice. In addition, to confirm the role and functions of neuronal Hb-α, we also utilized lentivirus CRISPR interference-based Hb-α knockdown (Hb-α CRISPRi KD) in the non-ischemic and ischemic mouse hippocampus and examined the effect on neuronal oxygenation, as well as induction of hypoxia-inducible factor-1α (HIF-1α) and its downstream pro-apoptotic factors, PUMA and NOXA, and on neuronal survival and neurodegeneration. The results of the study revealed an age-related decrease in neuronal Hb-α levels and correlated increase in hypoxia in the hippocampus and cortex of intact male and female mice. Sex differences were observed with males having higher neuronal Hb-α levels than females in all brain regions at all ages. In vivo Hb-α CRISPRi KD in the mouse hippocampus resulted in increased hypoxia and elevated levels of HIF-1α, PUMA and NOXA in the non-ischemic and ischemic mouse hippocampus, effects that were correlated with a significant decrease in neuronal survival and increased neurodegeneration. As a whole, these findings indicate that neuronal Hb-α decreases with age in mice and has an important role in regulating neuronal oxygenation and neuroprotection.

Association between the blood manganese (Mn) and hemoglobin in patients undergoing maintenance hemodialysis

BACKGROUND AND AIMS

Manganese (Mn) and iron metabolism are closely related. Iron metabolism disorders often lead to anemia in patients undergoing maintenance hemodialysis (MHD). Here, we aimed to investigate the relationship between blood Mn and hemoglobin (Hb) in patients undergoing MHD.

METHODS

Patients undergoing MHD in September 2019 were included in a cross-sectional study. Clinical and demographic data and blood samples were collected before hemodialysis sessions, and blood levels of Mn were measured by inductively coupled plasma mass spectrometry. Both multivariable linear and binary logistic regression analyses were performed to study the relationship between the blood Mn and Hb.

RESULTS

A total of 144 patients undergoing MHD were enrolled in the study. The patients had a mean age of 64.33 ± 13.39 years, median vintage of 33.50 (16.25-57.50) months. Among them, 66 were females (45.8%). The median blood Mn level was 13.55 µg/L (IQR:9.92-17.48). Ninety-nine patients were anemic (68.8%). The mean Hb level was 99.83 ± 19.68 g/L. The patient group with high blood Mn had a high proportion of females, and these patients had high levels of RBC, hemoglobin, Hct, UIBC, serum TCHOL, and serum LDL, yet short dialysis vintage, low prevalence of anemia, low levels of serum ferritin, serum iron, and TSAT. Following adjustment for confounding factors, we found that low blood Mn level was independently associated with lower Hb level and anemia in patients undergoing MHD by multivariate linear and multivariate binary logistic regression, respectively, in different models.

CONCLUSION

Whilst our study showed that high levels of blood Mn were independently associated with high hemoglobin in patients undergoing MHD, further multicenter studies with large sample sizes are still required.

Total cholesterol: a potential mediator of the association between exposure to acrylamide and hypertension risk in adolescent females

Acrylamide (AA) exposure is associated with a range of adverse health effects. However, whether AA exposure is related to hypertension in adolescents remains unclear. The associations of blood hemoglobin biomarkers of AA (HbAA) and its metabolite glycidamide (HbGA) with hypertension risk, diastolic blood pressure (DBP), and systolic blood pressure (SBP) were evaluated by multivariate logistic regression and linear regression. We identified a potential positive association between blood HbGA and hypertension risk in adolescent females (OR 1.81, 95% CI 1.00-3.30; P for trend = 0.022); however, there was no correlation in the non-linear model (P = 0.831). In the sex-stratified linear models, blood HbGA level had a strong positive association with SBP in adolescent females (beta 0.84, 95% CI 0.13-1.55, P = 0.020). Mechanistically, a one-unit increase in blood HbGA (ln transformed) was associated with a 2.83 mg/dL increase in total cholesterol (TC) among females in the fully adjusted model. Mediation analysis showed that TC mediated 24.15% of the association between blood HbGA level and the prevalence of hypertension in females. The present results provide epidemiological evidence that exposure to AA, mainly its metabolite glycidamide, is positively associated with the prevalence of hypertension or increased SBP in adolescent females.

Clinical parameters among patients in Japan with anemia and non-dialysis-dependent chronic kidney disease with and without diabetes mellitus who received roxadustat

Background

Roxadustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor for treating anemia of chronic kidney disease (CKD). This post hoc analysis of a Japanese, open-label, partially randomized, phase 3 study in patients with non-dialysis-dependent (NDD) CKD evaluated disease state–related parameters among patients with and without diabetes mellitus who received roxadustat. In the 1517-CL-0310 study (NCT02988973), roxadustat was noninferior to darbepoetin alfa for change in average hemoglobin levels at Weeks 18–24 from baseline who received roxadustat.

Methods

Patients enrolled in the 1517-CL-0310 study who received roxadustat were included in this post hoc analysis. Hematologic (hemoglobin, reticulocyte/erythrocyte ratio, mean corpuscular volume [MCV], and mean corpuscular hemoglobin [MCH]), iron-related (ferritin, total iron-binding capacity, transferrin, ceruloplasmin, and hepcidin), metabolic (HbA1c, glycated albumin, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol), and renal (eGFR) parameters were summarized descriptively by visit through Week 52.

Results

Among 201 included patients, 105 (52.2%) and 96 (47.8%) were in the Diabetes and No Diabetes subgroups, respectively. There were no clinically meaningful differences through Week 52 for most hematologic, iron-related, metabolic, or renal parameters between patients in the Diabetes and No Diabetes subgroups. MCV and MCH remained lower and HbA1c and glycated albumin remained higher in patients in the Diabetes subgroup through Week 52. Both subgroups experienced a similar benefit from roxadustat in maintaining hemoglobin levels in the target range of 10–12 g/dL.

Conclusion

Roxadustat maintained hemoglobin levels in the target range with similar clinical parameters irrespective of diabetes mellitus presence at baseline.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-022-02225-w.

Desidustat in Anemia due to Non-Dialysis-Dependent Chronic Kidney Disease: A Phase 3 Study (DREAM-ND)

BACKGROUND

Desidustat, an oral hypoxia-inducible factor prolyl hydroxylase inhibitor, is being developed to treat anemia in patients with chronic kidney disease (CKD) without dialysis dependency.

METHODS

In total, 588 patients with a clinical diagnosis of anemia due to CKD without dialysis need and with baseline hemoglobin of 7.0-10.0 g/dL (inclusive) were randomized in a 1:1 ratio to receive either desidustat 100 mg oral tablets thrice a week for 24 weeks or biosimilar darbepoetin subcutaneous injection 0.75 μg/kg once in 2 weeks for 24 weeks. The primary outcome was the change from baseline in hemoglobin to evaluation period of Weeks 16-24. Key secondary outcomes included the number of patients with hemoglobin response, changes in the hepcidin levels, changes in the vascular endothelial growth factor (VEGF) levels, and changes in the lipid and lipoprotein profiles.

RESULTS

Hemoglobin change from baseline to Weeks 16-24 was 1.95 g/dL in the desidustat group and 1.83 g/dL in the darbepoetin group (difference: 0.11 g/dL; 95% CI: -0.12, 0.34), which met prespecified non-inferiority margin (-0.75 g/dL). The hemoglobin responders were significantly higher (p = 0.0181) in the desidustat group (196 [77.78%]) compared to the darbepoetin group (176 [68.48%]). The difference of change in hepcidin from baseline to Week 12 and Week 24 (p = 0.0032 at Week 12, p = 0.0016 at Week 24) and the difference of change in low-density lipoprotein from baseline to Week 24 (p value = 0.0269) between the two groups was statistically significant. The difference of change from baseline in VEGF to Weeks 12 and 24 between the two groups was not statistically significant.

CONCLUSION

Desidustat is non-inferior to darbepoetin in the treatment of anemia due to non-dialysis dependent CKD and it is well-tolerated.

Molecular and cellular mechanisms that regulate human erythropoiesis

To enable effective oxygen transport, ∼200 billion red blood cells (RBCs) need to be produced every day in the bone marrow through the fine-tuned process of erythropoiesis. Erythropoiesis is regulated at multiple levels to ensure that defective RBC maturation or overproduction can be avoided. Here, we provide an overview of different layers of this control, ranging from cytokine signaling mechanisms that enable extrinsic regulation of RBC production to intrinsic transcriptional pathways necessary for effective erythropoiesis. Recent studies have also elucidated the importance of posttranscriptional regulation and highlighted additional gatekeeping mechanisms necessary for effective erythropoiesis. We additionally discuss the insights gained by studying human genetic variation affecting erythropoiesis and highlight the discovery of BCL11A as a regulator of hemoglobin switching through genetic studies. Finally, we provide an outlook of how our ability to measure multiple facets of this process at single-cell resolution, while accounting for the impact of human variation, will continue to refine our knowledge of erythropoiesis and how this process is perturbed in disease. As we learn more about this intricate and important process, additional opportunities to modulate erythropoiesis for therapeutic purposes will undoubtedly emerge.

Aging alters gastrocnemius muscle hemoglobin oxygen saturation (StO2) characteristics in healthy individuals

PURPOSE

Functional limitations during exercise from alterations in the balance of oxygen supply and demand-as reported by lower tissue oxygen saturation and longer recovery time-are well documented in clinical populations. We aimed to assess changes in skeletal muscle hemoglobin oxygen saturation (StO₂) characteristics during exercise as a result of aging in otherwise healthy individuals.

METHODS

We recruited healthy male and female participants (n = 101) from three age ranges-young (18-39 years), middle age (40-65 years), and older (> 65 years)-to complete exercise tests commonly used in clinical populations. Using near-infrared spectroscopy (NIRS) we assessed StO₂ in the medial gastrocnemius during the Gardner Treadmill Protocol and 6 min walk test (6MWT).

RESULTS

Minimum StO₂ (%) during the treadmill test was significantly lower for both middle-age (36.1 ± 20.6) and older (27.3 ± 19.4) participants compared to young (46.8 ± 14.8) (p < 0.05 and p < 0.01 respectively), and recovery time (minutes) was significantly prolonged (young = 0.22 ± 0.34; middle age = 0.66 ± 0.52; older = 1.04 ± 1.00) (p < 0.001 for both middle age and older compared to young). Similar results were shown during the 6MWT, as minimum StO₂ (%) was lower in middle-age (41.7 ± 17.2) and older (40.0 ± 25.9) participants compared to young (53.6 ± 14.5) (p < 0.05), and recovery times (minutes) were prolonged (young: 0.11 ± 0.17; middle age: 0.46 ± 0.42; older: 0.93 ± 0.43) (p < 0.001 for both middle age and older compared to young). Simple linear regression analyses demonstrated that age predicted treadmill recovery and 6MWT recovery.

CONCLUSION

Our study provides evidence that aging, even in otherwise healthy individuals, negatively impacts muscle StO₂ characteristics. In older individuals, working muscle tissue may reach lower oxygen saturation during exercise and take longer to return to baseline oxygen saturation post-exercise.

Altitude acclimatization, hemoglobin-oxygen affinity, and circulatory oxygen transport in hypoxia

In mammals and other air-breathing vertebrates that live at high altitude, adjustments in convective O₂ transport via changes in blood hemoglobin (Hb) content and/or Hb-O₂ affinity can potentially mitigate the effects of arterial hypoxemia. However, there are conflicting views about the optimal values of such traits in hypoxia, partly due to the intriguing observation that hypoxia-induced acclimatization responses in humans and other predominantly lowland mammals are frequently not aligned in the same direction as evolved phenotypic changes in high-altitude natives. Here we review relevant theoretical and empirical results and we highlight experimental studies of rodents and humans that provide insights into the combination of hematological changes that help attenuate the decline in aerobic performance in hypoxia. For a given severity of hypoxia, experimental results suggest that optimal values for hematological traits are conditional on the states of other interrelated phenotypes that govern different steps in the O₂-transport pathway.

New Insights into Hemopexin-Binding to Hemin and Hemoglobin

Hemopexin (Hx) is a plasma glycoprotein that scavenges heme (Fe(III) protoporphyrin IX). Hx has important implications in hemolytic disorders and hemorrhagic conditions because releasing hemoglobin increases the labile heme, which is potentially toxic, thus producing oxidative stress. Therefore, Hx has been considered for therapeutic use and diagnostics. In this work, we analyzed and mapped the interaction sequences of Hx with hemin and hemoglobin. The spot-synthesis technique was used to map human hemopexin (P02790) binding to hemin and human hemoglobin. A library of 15 amino acid peptides with a 10-amino acid overlap was designed to represent the entire coding region (aa 1-462) of hemopexin and synthesized onto cellulose membranes. An in silico approach was taken to analyze the amino acid frequency in the identified interaction regions, and molecular docking was applied to assess the protein-protein interaction. Seven linear peptide sequences in Hx were identified to bind hemin (H1-H7), and five were described for Hb (Hb1-Hb5) interaction, with just two sequences shared between hemin and Hb. The amino acid composition of the identified sequences demonstrated that histidine residues are relevant for heme binding. H105, H293, H373, H400, H429, and H462 were distributed in the H1-H7 peptide sequences, but other residues may also play an important role. Molecular docking analysis demonstrated Hx's association with the β-chain of Hb, with several hotspot amino acids that coordinated the interaction. This study provides new insights into Hx-hemin binding motifs and protein-protein interactions with Hb. The identified binding sequences and specific peptides can be used for therapeutic purposes and diagnostics as hemopexin is under investigation to treat different diseases and there is an urgent need for diagnostics using labile heme when monitoring hemolysis.

Oscillator decomposition of infant fNIRS data

The functional near-infrared spectroscopy (fNIRS) can detect hemodynamic responses in the brain and the data consist of bivariate time series of oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb) on each channel. In this study, we investigate oscillatory changes in infant fNIRS signals by using the oscillator decompisition method (OSC-DECOMP), which is a statistical method for extracting oscillators from time series data based on Gaussian linear state space models. OSC-DECOMP provides a natural decomposition of fNIRS data into oscillation components in a data-driven manner and does not require the arbitrary selection of band-pass filters. We analyzed 18-ch fNIRS data (3 minutes) acquired from 21 sleeping 3-month-old infants. Five to seven oscillators were extracted on most channels, and their frequency distribution had three peaks in the vicinity of 0.01-0.1 Hz, 1.6-2.4 Hz and 3.6-4.4 Hz. The first peak was considered to reflect hemodynamic changes in response to the brain activity, and the phase difference between oxy-Hb and deoxy-Hb for the associated oscillators was at approximately 230 degrees. The second peak was attributed to cardiac pulse waves and mirroring noise. Although these oscillators have close frequencies, OSC-DECOMP can separate them through estimating their different projection patterns on oxy-Hb and deoxy-Hb. The third peak was regarded as the harmonic of the second peak. By comparing the Akaike Information Criterion (AIC) of two state space models, we determined that the time series of oxy-Hb and deoxy-Hb on each channel originate from common oscillatory activity. We also utilized the result of OSC-DECOMP to investigate the frequency-specific functional connectivity. Whereas the brain oscillator exhibited functional connectivity, the pulse waves and mirroring noise oscillators showed spatially homogeneous and independent changes. OSC-DECOMP is a promising tool for data-driven extraction of oscillation components from biological time series data.

Helicobacter pylori infection and iron deficiency in non-elderly adults participating in a health check-up program

BACKGROUND/AIMS

Helicobacter pylori infection is presumably associated with iron deficiency and iron deficiency anemia (IDA). This study aimed to evaluate the relationship between H. pylori infection and the decline in iron stores in non-elderly adults during their health check-ups.

METHODS

We identified a total of 1,069 subjects who were tested for iron, ferritin, and total iron-binding capacity during their health check-ups, from January 2016 to May 2017. Of these, subjects who underwent endoscopy via rapid urease test and those aged 65 years or below were finally enrolled.

RESULTS

Overall, 281 subjects were enrolled, and 187 patients (66.5%) tested positive for H. pylori. The mean age was 36.1 years (range, 22 to 65), and 176 subjects (62.6%) were male. The mean levels of hemoglobin (14.1 ± 1.7 g/dL vs. 14.6 ± 1.4 g/dL, p = 0.019) and ferritin (121.7 ± 106.9 ng/mL vs. 151.8 ± 107.8 ng/mL, p = 0.027) in the H. pylori-positive group were significantly lower than those in the H. pylori-negative group. Iron deficiency (ferritin < 30 ng/mL) was more common in patients with H. pylori infection (p = 0.002). There was no significant difference in anemia (hemoglobin < 13 g/dL in men, < 12 g/dL in women) or IDA (anemia, ferritin < 10 ng/mL, and transferrin saturation < 16%) with H. pylori. Logistic regression analysis demonstrated that female sex (odds ratio, 197.559; 95% confidence interval, 26.461 to 1,475.015) and H. pylori infection (odds ratio, 3.033; 95% confidence interval, 1.216 to 7.567) were factors associated with iron deficiency.

CONCLUSION

H. pylori infection is associated with iron deficiency, suggesting a decline in iron stores among infected non-elderly adults.

Segmental flexibility of spectrin reflects erythrocyte membrane deformability

The frequency-dependent contribution of spectrin, the main cytoskeletal protein of red blood cell (RBC) membrane, to the complex admittance and capacitance of suspended RBCs have revealed two dielectric relaxations, βsp (1.4 MHz) and γ1sp (7 MHz). The strength of these relaxations was related to the ability of RBC membrane to deform. In this study the two relaxations were inhibited by N-ethylmaleimide (up to 5 mM), known to impair the RBC deformability, and the degree of inhibition, i.e., the number of accessible SH-groups on spectrin, depended on the deformation of RBC membrane. Dithiothreitol (up to 5 mM), which does not affect RBC deformability, did not affect the above dielectric relaxations in line with the absence of S-S groups on spectrin. Phenylhydrazine (up to 3 mM) and hydrogen hydroperoxide (up to 450 μM) are known to denature the haemoglobin of RBCs producing nanoparticles (globins) that bind to spectrin turning the RBC membrane rigid. At the same concentrations they were shown to inhibit progressively the two relaxations on spectrin. The results are in line with the involvement of some globin-sized segments of spectrin in the dielectric activity of spectrin and in the ability of RBC plasma membrane to deform.

The Oxidative Injury of Extracellular Hemoglobin Is Associated With Reactive Oxygen Species Generation of Grass Carp (Ctenopharyngodon idella)

Intravascular hemolysis is a fundamental feature of hemorrhagic venereal infection or tissue and releases the endogenous damage-associated molecular pattern hemoglobin (Hb) into the plasma or tissues, which results in systemic inflammation, vasomotor dysfunction, thrombophilia, and proliferative vasculopathy. However, how the cytotoxic Hb affects the tissues of grass carp remains unclear. Here, we established a hemolysis model in grass carp by injecting phenylhydrazine (PHZ). The data revealed that the PHZ-induced hemolysis increased the content of Hb and activated the antioxidant system in plasma. The histopathology analysis data showed that the PHZ-induced hemolysis increased the accumulation of Hb and iron both in the head and middle kidney. The results of quantitative real-time PCR (qRT-PCR) detection suggested that the hemolysis upregulated the expressions of iron metabolism-related genes. In addition, the immunofluorescence and immunohistochemistry data revealed that the hemolysis caused an obvious deposition of collagen fiber, malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE) accumulation and increased the content of oxidative-related enzymes such as β-galactosidase (β-GAL), lipid peroxide (LPO), and MDA in both the head and middle kidney. Furthermore, the PHZ-induced hemolysis significantly increased the production of reactive oxygen species (ROS), which resulted in apoptosis and modulated the expressions of cytokine-related genes. Taken together, excess of Hb released from hemolysis caused tissue oxidative damage, which may be associated with ROS and inflammation generation.

Lyophilized annelid mega-hemoglobin retains its' quaternary structure and oxygen equilibrium properties after room temperature storage for over 6 months

The long-term storage stability and portability of hemoglobin (Hb)-based oxygen carriers are important design criteria in the development of these therapeutics. Lyophilization or storing proteins in a freeze-dried form is known to increase storage lifetime and reduce overall weight. In this study, we lyophilized the extracellular mega-hemoglobin of the annelid Lumbricus terrestris and tested the storage stability at different temperatures and oxygenation conditions. Storage in refrigerated conditions for over 6 months in the presence of N2 reduced oxidation by 50% while storage at room temperature in the presence of N2 reduced oxidation by 60%, all while maintaining the structural stability of the mega-hemoglobin. We also demonstrated a reliable strategy to freeze dry Hbs in the presence of a minimally non-reducing disaccharide sugar that could be easily re-solubilized in deionized water. Overall, this study made significant advances towards long term storage stability of oxygen therapeutics for direct applications in transfusion medicine.

Hemoglobin Concentration during Early Pregnancy as an Accurate Predictor of Anemia during Late Pregnancy

It is undetermined which blood variables related to iron storage during the first trimester of pregnancy could efficiently predict anemia occurring during the third trimester. Red blood cell count (RBC), hemoglobin concentration, hematocrit, ferritin, iron, and total iron binding capacity (TIBC) were assessed longitudinally during the first, second, and third trimesters of 231 healthy Japanese women. None of the patients had anemia in the first trimester and none used iron supplementation before the second trimester blood test. Anemia was defined as hemoglobin (Hb) < 11 g/dL for the first trimester and Hb < 10.0 g/dL for the third trimester. Forty-seven (20%) women developed anemia in the third trimester. The first trimester RBC, Hb, hematocrit, and ferritin levels were significantly lower in women with third-trimester anemia than those without anemia. The first trimester hemoglobin level exhibited a greater area under the curve of the receiver operating characteristic curve for prediction of the third trimester anemia than other blood variables; the optimal cut-off (12.6 g/dL) of hemoglobin yielded a sensitivity of 83% (39/47). First trimester hemoglobin levels were significantly better predictors of anemia during the third trimester than the indices of iron storage, including serum iron, ferritin, and TIBC levels.

Biologic and Clinical Efficacy of LentiGlobin for Sickle Cell Disease

BACKGROUND

Sickle cell disease is characterized by the painful recurrence of vaso-occlusive events. Gene therapy with the use of LentiGlobin for sickle cell disease (bb1111; lovotibeglogene autotemcel) consists of autologous transplantation of hematopoietic stem and progenitor cells transduced with the BB305 lentiviral vector encoding a modified β-globin gene, which produces an antisickling hemoglobin, HbA^T87Q.

METHODS

In this ongoing phase 1-2 study, we optimized the treatment process in the initial 7 patients in Group A and 2 patients in Group B with sickle cell disease. Group C was established for the pivotal evaluation of LentiGlobin for sickle cell disease, and we adopted a more stringent inclusion criterion that required a minimum of four severe vaso-occlusive events in the 24 months before enrollment. In this unprespecified interim analysis, we evaluated the safety and efficacy of LentiGlobin in 35 patients enrolled in Group C. Included in this analysis was the number of severe vaso-occlusive events after LentiGlobin infusion among patients with at least four vaso-occlusive events in the 24 months before enrollment and with at least 6 months of follow-up.

RESULTS

As of February 2021, cell collection had been initiated in 43 patients in Group C; 35 received a LentiGlobin infusion, with a median follow-up of 17.3 months (range, 3.7 to 37.6). Engraftment occurred in all 35 patients. The median total hemoglobin level increased from 8.5 g per deciliter at baseline to 11 g or more per deciliter from 6 months through 36 months after infusion. HbA^T87Q contributed at least 40% of total hemoglobin and was distributed across a mean (±SD) of 85±8% of red cells. Hemolysis markers were reduced. Among the 25 patients who could be evaluated, all had resolution of severe vaso-occlusive events, as compared with a median of 3.5 events per year (range, 2.0 to 13.5) in the 24 months before enrollment. Three patients had a nonserious adverse event related or possibly related to LentiGlobin that resolved within 1 week after onset. No cases of hematologic cancer were observed during up to 37.6 months of follow-up.

CONCLUSIONS

One-time treatment with LentiGlobin resulted in sustained production of HbA^T87Q in most red cells, leading to reduced hemolysis and complete resolution of severe vaso-occlusive events. (Funded by Bluebird Bio; HGB-206 ClinicalTrials.gov number, NCT02140554.).

Scalable manufacturing platform for the production of methemoglobin as a non-oxygen carrying control material in studies of cell-free hemoglobin solutions

Methemoglobin (metHb) arises from the oxidation of ferrous hemoglobin (HbFe²⁺, Hb) to ferric hemoglobin (HbFe³⁺, metHb), which is unable to bind gaseous ligands such as oxygen (O₂) and carbon monoxide (CO), and binds to nitric oxide (NO) significantly slower compared to Hb. Therefore, metHb does not elicit vasoconstriction and systemic hypertension in vivo due to its extremely slow NO scavenging rate in comparison to cell-free Hb, but will induce oxidative tissue injury, demonstrating the potential of using metHb as a control material when studying the toxicity of cell-free Hb. Hence, the goal of this work was to develop a novel manufacturing strategy for production of metHb that is amenable to scale-up. In this study, small scale (e.g. 1 mL reaction volume) screening experiments were initially conducted to determine the optimal molar ratio of Hb to the oxidization agents hydrogen peroxide (H₂O₂) or sodium nitrite (NaNO₂) to achieve the highest conversion of Hb into metHb. A spectral deconvolution program was employed to determine the molar fraction of various species (hemichrome, metHb, oxyHb, metHb-NO2−, and NaNO₂) in solution during the oxidation reaction. From this analysis, either a 1:1 or 1:5 molar ratio was identified as optimal molar ratios of Hb:NaNO₂ (heme basis) that yielded the highest conversion of Hb into metHb with negligible amounts of side products. Hence in order to reduce the reaction time, a 1:5 molar ratio was chosen for large scale (i.e. 1.5 L reaction volume) synthesis of bovine metHb (metbHb) and human metHb (methHb). The biophysical properties of metHb were then characterized to elucidate the potential of using the synthesized metHb as a non-O₂ carrying control material. The haptoglobin binding kinetics of metHb were found to be similar to Hb. Additionally, the synthesized metHb was stable in phosphate buffered saline (PBS, 50 mM, pH 7.4) at 4°C for approximately one week, indicating the high stability of the material.