Shen Shuai II recipe improves renal hypoxia to attenuate renal injury in 5/6 renal ablation/infarction rats and effect evaluation using blood oxygenation level-dependent functional magnetic resonance imaging

Background: Renal hypoxia plays a key role in the progression of chronic kidney disease (CKD). Shen Shuai II Recipe (SSR) has shown good results in the treatment of CKD as a common herbal formula. This study aimed to explore the effect of SSR on renal hypoxia and injury in CKD rats. Methods: Twenty-five Wistar rats underwent 5/6 renal ablation/infarction (A/I) surgery were randomly divided into three groups: 5/6 (A/I), 5/6 (A/I) + losartan (LOS), and 5/6 (A/I) + SSR groups. Another eight normal rats were used as the Sham group. After 8-week corresponding interventions, blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) was performed to evaluate renal oxygenation in all rats, and biochemical indicators were used to measure kidney and liver function, hemoglobin, and proteinuria. The expression of fibrosis and hypoxia-related proteins was analyzed using immunoblotting examination. Results: Renal oxygenation, evaluated by BOLD-fMRI as cortical and medullary T2* values (COT2* and MET2*), was decreased in 5/6 (A/I) rats, but increased after SSR treatment. SSR also downregulated the expression of hypoxia-inducible factor-1α (HIF-1α) in 5/6 (A/I) kidneys. With the improvement of renal hypoxia, renal function and fibrosis were improved in 5/6 (A/I) rats, accompanied by reduced proteinuria. Furthermore, the COT2* and MET2* were significantly positively correlated with the levels of creatinine clearance rate (Ccr) and hemoglobin, but negatively associated with the levels of serum creatinine (SCr), blood urea nitrogen (BUN), serum cystatin C (CysC), serum uric acid (UA), 24-h urinary protein (24-h Upr), and urinary albumin:creatinine ratio (UACR). Conclusion: The degree of renal oxygenation reduction is correlated with the severity of renal injury in CKD. SSR can improve renal hypoxia to attenuate renal injury in 5/6 (A/I) rats of CKD.

Human erythrocytes under stress. Spectroscopic fingerprints of known oxidative mechanisms and beyond

In this work, we investigated the oxidative stress-related biochemical alterations in red blood cells (RBCs) and their membranes with the use of spectroscopic techniques. We aimed to show their great advantage for the in situ detection of lipid classes and secondary structures of proteins without the need for their extraction in the cellular environment. The exposition of the cells to peroxides, t-butyl hydroperoxide (tBOOH) or hydrogen peroxide (H2O2) led to different degradation processes encompassing the changes in the composition of membranes and structural modifications of hemoglobin (Hb). Our results indicated that tBOOH is generally a stronger oxidizing agent than H2O2 and this observation was congruent with the activity of superoxide and glutathione peroxidase. ATR-FTIR and Raman spectroscopies of membranes revealed that tBOOH caused primarily the partial loss and peroxidation of the lipids resulting in loss of the integrity of membranes. In turn, both peroxides induced several kinds of damage in the protein layer, including the partial decrease of their content and irreversible aggregation of spectrin, ankyrin, and membrane-bound globin. These changes were especially pronounced on the membrane surface where stress conditions induced the formation of β-sheets and intramolecular aggregates, particularly for tBOOH. Interestingly, nano-FTIR spectroscopy revealed the lipid peroxidative damage on the membrane surface in both cases. As far as hemoglobin was concerned, tBOOH and H2O2 caused the increase of the oxyhemoglobin species and conformational alterations of its polypeptide chain into β-sheets. Our findings confirm that applied spectroscopies effectively track the oxidative changes occurring in the structural components of red blood cells and the simplicity of conducting measurements and sample preparation can be readily applied to pharmacological and clinical studies.

Factors affecting responsiveness of vadadustat in patients with anemia associated with chronic kidney disease: a post-hoc subgroup analysis of Japanese phase 3 randomized studies

BACKGROUND

Vadadustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor developed for treating anemia in chronic kidney disease (CKD). The purpose of this post-hoc analysis was to investigate the factors affecting the responsiveness to vadadustat in anemia patients with nondialysis-dependent (NDD) or hemodialysis-dependent (HDD) CKD in two Japanese phase 3 studies.

METHODS

Of 151 and 162 patients enrolled in NDD-CKD and HDD-CKD studies, 136 and 140 patients, respectively, were included and divided into subgroups for the analysis. To assess vadadustat responsiveness, the resistance index was defined as the mean body weight-adjusted dose of vadadustat (mg/kg) at weeks 20-24 divided by the mean hemoglobin (g/dL) at weeks 20-24. Multivariate analysis was performed to identify the variables affecting the resistance index.

RESULTS

Independent factors identified as determinants for better response to vadadustat were as follows: high baseline hemoglobin, low baseline eGFR, high week-20-24 ferritin, and CKD not caused by autoimmune disease/glomerulonephritis/vasculitis in NDD-CKD; and male sex, high baseline C-reactive protein, and low baseline erythropoiesis-stimulating agent resistance index (ERI) in HDD-CKD.

CONCLUSIONS

In this post-hoc analysis, several factors were identified as affecting the response to vadadustat. These results may provide useful information leading to an appropriate dose modification for vadadustat.

CLINICAL TRIAL REGISTRATION

NCT03329196 (MT-6548-J01) and NCT03439137 (MT-6548-J03).

Soluble mannose receptor: A potential biomarker in Gaucher disease

PURPOSE

Soluble mannose receptor (sMR) relates to mannose receptor expression on macrophages, and is elevated in inflammatory disorders. Gaucher disease (GD) has altered macrophage function and utilises mannose receptors for enzyme replacement therapy (ERT) endocytosis. sMR has not previously been studied in GD.

METHODS

sMR was measured by ELISA and correlated with GD clinical features including spleen and liver volume, haemoglobin and platelet count, bone marrow burden (BMB) scores and immunoglobulin levels. sMR was compared with biomarkers of GD: chitotriosidase, lyso-GL1, PARC, CCL3, CCL4, osteoactivin, serum ACE and ferritin.

RESULTS

Median sMR in untreated GD patients was 303.0 ng/mL compared to post-treatment 190.9 ng/mL (p = .02) and healthy controls 202 ng/mL. Median sMR correlated with median spleen volume 455 mL (r = .70, p = .04), liver volume 2025 mL (r = .64, p = .04), BMB 7 (r = .8, p = .03), IgA 1.9 g/L (r = .54, p = .036), IgG 9.2 g/L (r = .57, p = .027), IgM 1.45 g/L (r = .86, p < .0001), with inverse correlation to median platelet count of 125 × 109/L (r = -.47, p = .08) and haemoglobin of 137 g/L (r = -.77, p = .0008). sMR correlated with established biomarkers: osteoactivin 107.8 ng/mL (r = .58, p = .0006), chitotriosidase 3042 nmol/mL/h (r = .52, p = .0006), PARC 800 ng/mL (r = .67, p = .0068), ferritin 547 μg/L (r = .72, p = .002) and CCL3 50 pg/mL (r = .67, p = .007).

CONCLUSIONS

sMR correlates with clinical features and biomarkers of GD and reduces following therapy.

Systematic scoping review: Use of the faecal immunochemical test residual buffer to enhance colorectal cancer screening

BACKGROUND

The faecal immunochemical test (FIT) is an inexpensive and convenient modality to screen for colorectal cancer. However, its one-time sensitivity for detecting colorectal cancer and cancer precursors is limited. There is growing interest in using the non-haemoglobin contents of FIT residual buffer to enhance colonic neoplasia detection.

AIM

To establish from the literature a framework to catalogue candidate biomarkers within FIT residual buffer for non-invasive colorectal cancer screening.

METHODS

The search strategy evaluated PubMed, Scopus, Web of Science, Embase, and Google Scholar for publications through 25 October 2023, with search terms including FIT, buffer, OC-sensor, biomarkers, microbiome, microRNA (miR), colon, rectum, screening, neoplasm, and early detection. Studies employing home-based collection samples using quantitative FIT first processed for haemoglobin were included. One author reviewed all articles; a second author completed a 20% full-text audit to ensure adherence to eligibility criteria.

RESULTS

A broad search yielded 1669 studies and application of eligibility criteria identified 18 relevant studies. Multiple protein, DNA/RNA, and microbiome biomarkers (notably haptoglobin, miR-16, miR-27a-3p, miR-92a, miR-148a-3p, miR-223, miR-421, let-7b-5p, and Tyzzerella 4) were associated with colorectal neoplasia. Furthermore, studies highlighted the short-term stability of biomarkers for clinical use and long-term stability for research purposes.

CONCLUSIONS

This scoping review summarises the framework and progress of research on stability of biomarkers in FIT residual buffer and their associations with colorectal neoplasia to guide opportunities for further confirmatory studies to enhance colorectal cancer screening.

Relationship Between Hemoglobin Concentration and Cardiovascular Disease Mortality in a 25-Year Follow-up Study of a Japanese General Population - NIPPON DATA90

BACKGROUND

Deviations of hemoglobin from normal levels may be a factor in cardiovascular disease (CVD) risk; however, conclusive evidence is lacking. In addition, preclinical conditions may influence hemoglobin concentrations, but studies focusing on reverse causation are limited. Thus, we examined the relationship between hemoglobin concentrations and CVD mortality risk, considering reverse causation.Methods and Results: In a prospective cohort representative of the general Japanese population (1990-2015), we studied 7,217 individuals (mean age 52.3 years; 4,219 women) without clinical CVD at baseline. Participants were categorized into sex-specific hemoglobin quintiles (Q1-Q5) and data were analyzed using the Cox proportional hazards model adjusted for possible confounders. During a 25-year follow-up, 272 men and 334 women died from CVD. Adjusted hazard ratios for CVD mortality across sex-specific quintiles, using Q3 as the reference, were significantly higher for Q1 (1.40; 95% confidence interval [CI] 1.08-1.82) and Q5 (1.49; 95% CI 1.14-1.96), and remained significant after excluding deaths within the first 5 years of follow-up to consider reverse causation (1.35 [95% CI 1.02-1.79] and 1.45 [95% CI 1.09-1.94], respectively). A similar U-shaped association was seen between transferrin saturation levels and CVD mortality, but after excluding deaths within the first 5 years the association was significant only for Q1.

CONCLUSIONS

Low and high hemoglobin concentrations were associated with an increased risk of CVD mortality.

Evaluation of calibrated and uncalibrated optical imaging approaches for relative cerebral oxygen metabolism measurements in awake mice

Objective. The continuous delivery of oxygen is critical to sustain brain function, and therefore, measuring brain oxygen consumption can provide vital physiological insight. In this work, we examine the impact of calibration and cerebral blood flow (CBF) measurements on the computation of the relative changes in the cerebral metabolic rate of oxygen consumption (rCMRO2) from hemoglobin-sensitive intrinsic optical imaging data. Using these data, we calculate rCMRO2, and calibrate the model using an isometabolic stimulus.Approach. We used awake head-fixed rodents to obtain hemoglobin-sensitive optical imaging data to test different calibrated and uncalibrated rCMRO2models. Hypercapnia was used for calibration and whisker stimulation was used to test the impact of calibration.Main results. We found that typical uncalibrated models can provide reasonable estimates of rCMRO2with differences as small as 7%-9% compared to their calibrated models. However, calibrated models showed lower variability and less dependence on baseline hemoglobin concentrations. Lastly, we found that supplying the model with measurements of CBF significantly reduced error and variability in rCMRO2change calculations.Significance. The effect of calibration on rCMRO2calculations remains understudied, and we systematically evaluated different rCMRO2calculation scenarios that consider including different measurement combinations. This study provides a quantitative comparison of these scenarios to evaluate trade-offs that can be vital to the design of blood oxygenation sensitive imaging experiments for rCMRO2calculation.

Haem iron versus ferrous iron salts to treat iron deficiency anaemia in Gambian children: protocol for randomised controlled trial {1}

BACKGROUND

The World Health Organization recommends universal iron supplementation for children aged 6-23 months in countries where anaemia is seen in over 40% of the population. Conventional ferrous salts have low efficacy due to low oral absorption in children with inflammation. Haem iron is more bioavailable, and its absorption may not be decreased by inflammation. This study aims to compare daily supplementation with haem iron versus ferrous sulphate on haemoglobin concentration and serum ferritin concentration after 12 weeks of supplementation.

METHODS

This will be a two-arm, randomised controlled trial. Gambian children aged 6-12 months with anaemia will be recruited within a predefined geographical area and recruited by trained field workers. Eligible participants will be individually randomised using a 1:1 ratio within permuted blocks to daily supplementation for 12 weeks with either 10.0 mg of elemental iron as haem or ferrous sulphate. Safety outcomes such as diarrhoea and infection-related adverse events will be assessed daily by the clinical team (see Bah et al. Additional file 4_Adverse event eCRF). Linear regression will be used to analyse continuous outcomes, with log transformation to normalise residuals as needed. Binary outcomes will be analysed by binomial regression or logistic regression, Primary analysis will be by modified intention-to-treat (i.e., those randomised and who ingested at least one supplement dose of iron), with multiple imputations to replace missing data. Effect estimates will be adjusted for baseline covariates (C-reactive protein, alpha-1-acid glycoprotein, haemoglobin, ferritin, soluble transferrin receptor).

DISCUSSION

This study will determine if therapeutic supplementation with haem iron is more efficacious than with conventional ferrous sulphate in enhancing haemoglobin and ferritin concentrations in anaemic children aged 6-12 months.

TRIAL REGISTRATION

Pan African Clinical Trial Registry PACTR202210523178727.

Impact of supplementation with iron-folic acid (IFA) and vitamin D3 compared with IFA alone on haemoglobin levels in elderly people with mild-to-moderate anaemia: protocol for the double-blind, randomised, placebo-controlled Iron and vitamin D trial in Elderly Anemia (IDEA)

INTRODUCTION

Anaemia in the elderly is often difficult to treat with iron supplementation alone as prevalence of anaemia of chronic disease (ACD) alone or mixed with iron-deficiency anaemia (IDA) is high in this age group. Hepcidin remains high in ACD, preventing utilisation of iron for heme synthesis. Vitamin D3 has shown hepcidin suppression activity in both in vitro and in vivo studies. As there is no study assessing the effect of iron-folic acid (IFA) with vitamin D3 on haemoglobin levels in the elderly in India, we want to conduct this study to estimate the impact of supplementation of a therapeutic package of IFA and vitamin D3 on haemoglobin levels in the elderly with mild-to-moderate anaemia in comparison with IFA only. The study will also assess the impact of the proposed intervention on ferritin, hepcidin, 25-hydroxyvitamin D, C reactive protein (CRP) and parathyroid hormone (PTH) levels.

METHODS AND ANALYSIS

This study is a community-based, double-blind, placebo-controlled, randomised trial. The study will be done in the Kalyani municipality area. Individuals aged ≥60 years with mild-to-moderate anaemia and normal vitamin D3 levels will be randomised into the intervention (IFA and vitamin D3 supplementation) group or the control group (IFA and olive oil as placebo). All medications will be self-administered. Follow-up will be done on a weekly basis for 12 weeks. The calculated sample size is 150 in each arm. Block randomisation will be done. The primary outcome is change in haemoglobin levels from baseline to 12 weeks. Secondary outcome is change in serum ferritin, 25-hydroxyvitamin D, hepcidin, CRP and PTH levels from baseline to 12 weeks.

ETHICS AND DISSEMINATION

Ethical approval from the Institutional Ethics Committee of All India Institute of Medical Sciences Kalyani has been obtained (IEC/AIIMS/Kalyani/Meeting/2022/03). Written informed consent will be obtained from each study participant. The trial results will be reported through publication in a reputable journal and disseminated through health talks within the communities.

TRIAL REGISTRATION NUMBER

CTRI/2022/05/042775.

PROTOCOL VERSION

Version 1.0.

Identification of small molecules affecting the interaction between human hemoglobin and Staphylococcus aureus IsdB hemophore

Human hemoglobin (Hb) is the preferred iron source of Staphylococcus aureus. This pathogenic bacterium exploits a sophisticated protein machinery called Iron-regulated surface determinant (Isd) system to bind Hb, extract and internalize heme, and finally degrade it to complete iron acquisition. IsdB, the surface exposed Hb receptor, is a proven virulence factor of S. aureus and the inhibition of its interaction with Hb can be pursued as a strategy to develop new classes of antimicrobials. To identify small molecules able to disrupt IsdB:Hb protein-protein interactions (PPIs), we carried out a structure-based virtual screening campaign and developed an ad hoc immunoassay to screen the retrieved set of commercially available compounds. Saturation-transfer difference (STD) NMR was applied to verify specific interactions of a sub-set of molecules, chosen based on their efficacy in reducing the amount of Hb bound to IsdB. Among molecules for which direct binding was verified, the best hit was submitted to ITC analysis to measure the binding affinity to Hb, which was found to be in the low micromolar range. The results demonstrate the viability of the proposed in silico/in vitro experimental pipeline to discover and test IsdB:Hb PPI inhibitors. The identified lead compound will be the starting point for future SAR and molecule optimization campaigns.

Functional characterization of RhuB as a second TonB2-dependent hemin receptor in Riemerella anatipestifer CH-1

In the previous study, it was shown that Riemerella anatipestifer (R. anatipestifer, RA), a pathogen in ducks and some other birds, encodes a hemin uptake system. The R. anatipestifer hemin uptake receptor RhuR is a TonB2-dependent hemin transporter. However, it remains unclear whether R. anatipestifer encodes additional TonB-dependent hemin transporters. Herein, we demonstrated that R. anatipestifer hemin uptake receptor B (RhuB) of R. anatipestifer CH-1 (RA CH-1) was negatively regulated by iron and mediated by the Fur protein, and knocking out rhuB damaged the ability of RA CH-1 to utilize iron from duck hemoglobin (Hb) but not that from duck serum. Moreover, the ability to use iron from Hb was restored by the expression rhuB in trans. Furthermore, the RhuB of RA CH-1 is a membrane protein, and recombinant RhuB could bind hemin at a 1:1 molar ratio in vitro. Compared to that of ΔtonB1ΔrhuR, the ability of ΔtonB1ΔrhuRΔrhuB to utilize hemin was impaired; meanwhile, compared to that of ΔtonB2ΔrhuR, the hemin utilization ability of ΔtonB2ΔrhuRΔrhuB was not affected, indicating that RhuB is a TonB2-dependent receptor. Compared to ΔrhuB, ΔrhuBΔrhuA did not affect hemin utilization. However, compared to ΔrhuA, ΔrhuBΔrhuA had reduced ability to utilize hemin, suggesting that RhuA relies on RhuB for its activity. Finally, the deletion of rhuB did not affect the virulence of RA CH-1. These results suggested that RhuB encodes a TonB2-dependent hemin receptor. The characterization of the second TonB-dependent receptor in R. anatipestifer enriches our understanding of the hemin uptake system of this bacterium.IMPORTANCEIron is essential for the survival of most bacteria, and hemin of hemoglobin can serve as an important iron source. In our previous studies, we showed that R. anatipestifer CH-1 encodes a TonB2-dependent hemin receptor RhuR, which is involved in hemin uptake. The deletion of rhuR did not abolish hemin utilization by RA CH-1. We hypothesized that additional hemin uptake systems exist in this bacterium. In this study, we identified the second TonB2-dependent hemin receptor RhuB in RA CH-1 through hemin utilization, protein localization, and hemin-binding experiments. The duck infection model showed that the deletion of rhuB did not affect the virulence of RA CH-1. This study is not only important for further understanding the hemin utilization mechanism of R. anatipestifer, but also for enriching the hemin uptake transporters of gram-negative bacteria.

Management of iron deficiency in women of childbearing age with oral iron intolerance: a prospective, randomised, controlled trial of three doses of an iron-whey-protein formulation : Prospective RandomisEd study of women of Childbearing age with gastroInteStinal Intolerance to Oral iroN (PRECISION)

BACKGROUND

Nutritional deficit and oral iron gastrointestinal intolerance may be a common cause of iron deficiency, which can be managed by pharmacists.

AIM

To understand the prevalence of iron deficiency in women of childbearing age with a self-reported history of intolerance to oral iron and the tolerability of three doses of an iron-whey-protein formulation in the care of these women.

METHOD

Ferritin and haemoglobin levels were documented in women of childbearing age with oral iron gastrointestinal intolerance. In those with iron deficiency (ferritin < 30 µg/L), adherence, gastrointestinal tolerability, ferritin, transferrin saturation and haemoglobin levels were compared between their prior oral iron product and iron-whey-protein microspheres randomised to three doses (14 mg daily, 25 mg daily and 50 mg daily) for 12 weeks.

RESULTS

Most screened women had low iron stores (128 (62.7%); ferritin < 30 µg/L), 65 (31.9%) had moderate to severe iron deficiency (ferritin < 12 µg/L) and 33 (16.2%) had iron deficiency anaemia (ferritin < 30 µg/L, haemoglobin < 12 g/dL). Amongst the 59 women who participated in the prospective clinical study of iron-whey-protein microspheres over 12 weeks, 48 (81.4%) were classified as adherent/persistent and fewer instances of gastrointestinal intolerance were reported (0.59 ± 0.91) when compared to 12 (20.3%) and (4.0 ± 2.2) respectively while taking the prior oral iron (Fisher's Exact and T-test respectively, both p < 0.001). There was no difference in adherence or tolerability of different iron-whey-protein formulation doses. Ferritin, haemoglobin and energy levels increased significantly over 12 weeks.

CONCLUSION

Undiagnosed iron deficiency is common in women of childbearing age with a history of intolerance to oral iron and iron-whey-protein microspheres can improve adherence, GI tolerability, iron stores, haemoglobin and energy levels in these women.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov identifier (registration includes full trial protocol): NCT04778072.

Intermittent neck flexion induces greater sternocleidomastoid deoxygenation than inspiratory threshold loading

PURPOSE

To compare deoxygenation of the sternocleidomastoid, scalenes, and diaphragm/intercostals (Dia/IC) during submaximal intermittent neck flexion (INF) versus submaximal inspiratory threshold loading (ITL) in healthy adults.

METHODS

Fourteen participants performed a randomized, cross-over, repeated measures design. After evaluation of maximal inspiratory pressures (MIP) and maximum voluntary contraction (MVC) for isometric neck flexion, participants were randomly assigned to submaximal ITL or INF until task failure. At least 2 days later, they performed the submaximal exercises in the opposite order. ITL or INF targeted 50 ± 5% of the MIP or MVC, respectively, until task failure. Near-infrared spectroscopy (NIRS) was applied to evaluate changes of deoxy-hemoglobin (ΔHHb), oxy-hemoglobin (ΔO2Hb), total hemoglobin (ΔtHb), and tissue saturation of oxygen (StO2) of the sternocleidomastoid, scalenes, and Dia/IC. Breathlessness and perceived exertion were evaluated using Borg scales.

RESULTS

Initially during INF, sternocleidomastoid HHb slope was greatest compared to the scalenes and Dia/IC. At isotime (6.5-7 min), ΔtHb (a marker of blood volume) and ΔO2Hb of the sternocleidomastoid were higher during INF than ITL. Sternocleidomastoid HHb, O2Hb, and tHb during INF also increased at quartile and task failure timepoints. In contrast, scalene ΔO2Hb was higher during ITL than INF at isotime. Further, Dia/IC O2Hb and tHb increased during ITL at the third quartile and at task failure. Borg scores were lower at task failure during INF compared to ITL.

CONCLUSION

Intermittent INF induces significant metabolic activity of the sternocleidomastoid and a lower perception of effort, which may provide an alternative inspiratory muscle training approach for mechanically ventilated patients.

Daprodustat for Post-Transplant Anemia in Renal Transplant Recipients

BACKGROUND

Daprodustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor, has been reported to be effective in treating conservative renal failure and renal anemia in patients undergoing dialysis. However, its effects on post-transplant anemia have not yet been reported. This study aimed to determine whether daprodustat may be a useful treatment for post-transplant anemia.

MATERIALS

Excluding 5 cases in which the drug was discontinued due to side effects, 21 post-transplant patients treated with daprodustat for ≥12 months and available for follow-up were analyzed. Changes in hemoglobin levels, iron metabolism, estimated glomerular filtration rate, and low-density lipoprotein levels were evaluated over 1 year.

RESULTS

The average hemoglobin level was 10.1 g/dL before treatment, and after 1, 2, 3, 6, 9, and 12 months, these had increased significantly to 10.9, 11.2, 11.9, 12.3, 12.3, and 12.6, respectively. Ferritin levels were significantly lower throughout the 12-month study period. Transferrin saturation was significantly lower than before treatment during the first 6 months, with no significant differences after that. The participants' estimated glomerular filtration rate and low-density lipoprotein cholesterol levels did not change significantly throughout the treatment.

CONCLUSION

Daprodustat significantly increased hemoglobin levels was easily dose-adjusted and was relatively safe for continuous use over 1 year. It was also effective in patients who had responded inadequately to erythropoiesis-stimulating agents. Therefore, we conclude that daprodustat may be a useful treatment for post-transplant anemia.

Theranova versus FX80: The impact on anemia management in hemodialysis

BACKGROUND

Middle uremic toxins (MUTs) can cause anemia and erythropoietin hyporesponsiveness. Theranova dialyzers may improve anemia management by removing MUTs. Hence, the impact of Theranova dialyzers on erythropoietin responsiveness was studied.

METHODS

This exploratory single-center prospective observational study, encompassing 50 patients undergoing dialysis with either the Theranova-400 or FX80 membrane for 6 months, involved monthly tracking of hemoglobin levels, weight-adjusted erythropoiesis-stimulating agent (w-ESA) dosing, and erythropoietin resistance index (ERI), with ESA treatment decisions guided by a proprietary algorithm.

RESULTS

The groups were similar in terms of demographics and baseline laboratory test results. The median hemoglobin levels, w-ESA and ERI, were found to be similar between FX80 and Theranova-400 groups at both baseline (11.06 vs 10.57, p = 0.808; 92.3 vs 105.2, p = 0.838; 8.1 vs 10.48, p = 0.876) and the end of the study (11.43 vs 11.03, p = 0.076; 48.7 vs 71.5; 4.48 vs 6.41, p = 0.310), respectively. There was a trend toward lower w-ESA and ERI at the end of the study compared to baseline in both groups, but the difference was non-significant.

CONCLUSIONS

Based on this study of 50 patients undergoing high-flux dialysis with near-target hemoglobin levels, switching to Theranova 400 dialyzers compared to FX80 dialyzers did not show statistically significant differences in maintaining hemoglobin levels, reducing ESA dose, or lowering ERI. The non-randomized design and small sample size limit the study's power to detect true differences. Larger, randomized trials are needed to confirm findings and definitively assess Theranova 400's benefits.

Unconventional role of Rab4 in the secretory pathway in Leishmania

Leishmania donovani is an auxotroph for heme. Parasite acquires heme by clathrin-mediated endocytosis of hemoglobin by specific receptor. However, the regulation of receptor recycling pathway is not known in Leishmania. Here, we have cloned, expressed and characterized the Rab4 homologue from L. donovani. We have found that LdRab4 localizes in both early endosomes and Golgi in L. donovani. To understand the role of LdRab4 in L. donovani, we have generated transgenic parasites overexpressing GFP-LdRab4:WT, GFP-LdRab4:Q67L, and GFP-LdRab4:S22N. Our results have shown that overexpression of GFP-LdRab4:Q67L or GFP-LdRab4:S22N does not alter the cell surface localization of hemoglobin receptor in L. donovani. Surprisingly, we have found that overexpression of GFP-LdRab4:S22N significantly blocks the transport of Ldgp63 to the cell surface whereas the trafficking of Ldgp63 is induced to the cell surface in GFP-LdRab4:WT and GFP-LdRab4:Q67L overexpressing parasites. Consequently, we have found significant inhibition of gp63 secretion by GFP-LdRab4:S22N overexpressing parasites whereas secretion of Ldgp63 is enhanced in GFP-LdRab4:WT and GFP-LdRab4:Q67L overexpressing parasites in comparison to untransfected control parasites. Moreover, we have found that survival of transgenic parasites overexpressing GFP-LdRab4:S22N is severely compromised in macrophages in comparison to GFP-LdRab4:WT and GFP-LdRab4:Q67L expressing parasites. These results demonstrated that LdRab4 unconventionally regulates the secretory pathway in L. donovani.

Associations of fish and meat intake with iron and anaemia in Malawian children

Animal flesh foods are rich in bioavailable iron but infrequently consumed by young children. We aimed to determine whether flesh food intake was associated with iron and anaemia status among 585 Malawian infants enroled in a 6-month egg-feeding trial. The percentage of days of small fish, large fish and meat consumption were assessed through weekly 7-day animal-source food screeners. Grams of intake were assessed through 24-h recalls conducted at 6-9, 9-12 and 12-15 months of age. Plasma ferritin, soluble transferrin receptor (sTfR) and haemoglobin concentrations were measured at 6-9 and 12-15 months of age. Iron biomarkers were adjusted for inflammation during analysis. At enrolment, each flesh food category was consumed by <5% of children in the past 24 h. Over the next 6 months, small fish, large fish and meat were consumed on 25%, 8% and 6% of days, respectively, with mean usual intakes of <5 g/day. More frequent small fish consumption was associated with lower sTfR (geometric mean ratio [95% CI]: 0.98 mg/L [0.96, 1.00] per 10 percentage point difference) but not ferritin (1.03 µg/L [0.98, 1.07]) or haemoglobin (1.01 g/dL [1.00, 1.01]). Large fish consumption was associated with higher anaemia (prevalence ratio [95% CI]: 1.09 [1.01, 1.19]) and lower iron deficiency (0.96 [0.93, 1.00]) prevalence. Gram intakes of flesh food categories were not associated with any iron or anaemia indicators. Small fish were a primary contributor to flesh food intake in this cohort of Malawian children, although usual portions were small. Fish was associated with modest improvements to iron status, but meat was too infrequent to be associated with anaemia and iron deficiency.

A single coelomic cell type is involved in both immune and respiratory functions of the coastal bioindicator annelid: Capitella C-Channel1 from the English Channel

The polychaete Capitella is a typical member of the 'thiobiome', and is commonly used as an eutrophication indicator species in environmental assessment studies. To deal with a sulfide-rich and poisonous surrounding, cells in close contact with the environment, and thus able to play a major role in detoxication and survival, are circulating cells. This work aimed to morpho-functionally describe the circulating coelomic cells of Capitella from the English Channel inhabiting the sulfide-rich mud in Roscoff Harbor. In general, worms have three types of circulating cells, granulocytes involved in bacterial clearance and defense against microorganisms, eleocytes with an essentially trophic role and elimination of cellular waste, and erythrocytes which play a role in detoxification and respiration via their intracellular hemoglobin. By combining diverse microscopic and cellular approaches, we provide evidence that Capitella does not possess granulocytes and eleocytes, but rather a single abundant rounded cell type with the morphological characteristics of erythrocytes i.e. small size and production of intracellular hemoglobin. Surprisingly, our data show that in addition to their respiratory function, these red cells could exert phagocytic activities, and produce an antimicrobial peptide. This latter immune role is usually supported by granulocytes. Our data highlight that the erythrocytes of Capitella from the English Channel differ in morphology and bear more functions than the erythrocytes of other annelids. The simplicity of this multi-task (or polyvalent) single-cell type makes Capitella an interesting model for studies of the impact of the environment on the immunity of this bioindicator species.

Effects of the Omicron variant of coronavirus disease 2019 on anaemia treatment for patients undergoing peritoneal dialysis

AIM

Patients undergoing dialysis are at high risk for coronavirus disease 2019 (COVID-19). Haemoglobin (Hb) levels may be changed in patients infected with the Omicron variant of COVID-19 who are undergoing peritoneal dialysis (PD). Therefore, we aimed to explore the effect of anti-anaemia treatment on such patients.

METHODS

This study enrolled patients undergoing PD who were infected with the Omicron variant of COVID-19 at our centre between November 2022 and February 2023. We retrospectively analysed changes in Hb levels and explored the effectiveness of roxadustat and recombinant human erythropoietin (rhEPO) for patients infected with the Omicron variant of COVID-19.

RESULTS

Among 125 enrolled patients, 83 (66.4%) were infected with the Omicron variant and 75 (90.4%) patients mainly experienced mild or moderate disease. During infection, C-reactive protein (CRP) levels were higher than those before infection (p < .001). Additionally, their CRP levels were negatively correlated with Hb levels (p = .002). However, Hb levels were decreased 1 month after infection (109.61 ± 10.64 g/L vs. 115.69 ± 12.04 g/L; p < .001). The roxadustat treatment group did not exhibit significantly decreased Hb levels 1 month after infection (114.57 ± 14.11 vs. 117.51 ± 10.74 g/L; p = .225). Conversely, the rhEPO treatment group experienced a mild decrease in Hb levels (108.69 ± 11.20 vs. 115.03 ± 12.23 g/L; p = .001). Ferritin levels increased in both groups during infection (p = .495). Two months after infection, ferritin levels (median, 205.0 ng/mL) were significantly decreased compared with during infection (median, 377.4 ng/mL) (p < .001) in the roxadustat treatment group.

CONCLUSION

Roxadustat was effective than rhEPO for treating anaemia in patients undergoing PD who were infected with the Omicron variant of COVID-19.

Compliance With NCCN Guidelines for Evaluation and Treatment of Anemia Among Patients With Solid Tumors

BACKGROUND

NCCN Guidelines for Hematopoietic Growth Factors recommend evaluation and treatment of anemia in patients with cancer. However, a paucity of data exists regarding compliance with these recommendations.

METHODS

A retrospective cohort study was performed of patients diagnosed with any solid tumor at Vanderbilt University Medical Center from 2008 to 2017. Tumor registry-confirmed cancer cases were identified by ICD-O codes using the Synthetic Derivative database. Anemia was defined as hemoglobin (Hgb) level ≤11 g/dL and graded according to CTCAE version 5.0. Absolute, functional, and possible functional iron deficiency were defined based on NCCN Guidelines.

RESULTS

A total of 25,018 patients met inclusion criteria. Median age was 60 years. The most common malignancies were respiratory tract, prostate, and nonprostate urologic (11% each). Among 8,695 patients with Hgb levels available prior to diagnosis, 1,484 (17%) were noted to be anemic proximal to diagnosis. Of the 25,018 patients, 11,019 (44%) were anemic within 6 months of diagnosis. Of these patients, 4,686 (43%) had grade 2 (moderate) anemia and 9,623 (87%) had normocytic anemia. Patients with retroperitoneal/peritoneal cancers had the highest prevalence of anemia (83/110; 75%). A total of 4,125 (37%) underwent any evaluation of their anemia, of whom 1,742 (16%) had iron studies performed and 1,528 (14%) had vitamin B12 or folate studies performed. Fewer than half of patients with anemia received treatment (n=4,318; 39%), including blood transfusion (n=3,528; 32%), oral iron supplementation (n=1,279; 12%), or intravenous iron supplementation (n=97; 1%). Anemia treatment was significantly more frequent as the grade of anemia increased (any treatment among grade 1/mild: 12%; grade 2/moderate: 31%; grade 3/severe: 77%; χ2 [2, n=11,019]=3,020.6; P<.001). Patients with penile and testicular cancers had the highest prevalence of anemia evaluation (n=57; 79%).

CONCLUSIONS

Anemia is common in patients with solid tumors; yet, compliance with NCCN Guidelines for evaluation and treatment of anemia remains low. There are opportunities to improve compliance with guidelines across the spectrum of cancer care.

The predictive value of the HALP score for no-reflow phenomenon and short-term mortality in patients with ST-elevation myocardial infarction

OBJECTIVE

ST-elevation myocardial infarction (STEMI) is a medical emergency demanding immediate intervention, and primary percutaneous coronary intervention (pPCI) is the standard of care for this condition. While PCI has proven highly effective, a subset of patients experience the devastating no-reflow phenomenon, and some face increased short-term mortality. The Hemoglobin, Albumin, Lymphocyte, and Platelet (HALP) score, a novel biomarker-based tool, has recently surfaced as an innovative predictor of these adverse outcomes. This study aims to investigate the groundbreaking findings that designate a low HALP score as a robust risk factor for no-reflow and short-term mortality in STEMI patients.

METHODS

1817 consecutive STEMI patients who underwent pPCI were included in this retrospective study, and the patients were divided into two groups according to whether no-reflow developed or not, and the HALP scores of the groups were compared. In addition, short-term mortality was compared between the study groups according to their HALP score values. The predictive ability of the HALP score for no-reflow was evaluated using a receiver operating characteristic curve.

RESULTS

No-reflow developed in 198 (10.1%) of the patients included in the study. HALP score value was found to be significantly lower in the no-reflow group (27 ± 13 vs 47 ± 24, p < 0.001). After multivariable adjustment, the HALP score was an independent predictor of no-reflow (OR, 0.923, 95% CI, 0.910-0.935, p < 0.001). Furthermore, the HALP score showed good discrimination for no-reflow (AUC, 0.771, 95% CI, 0.737-0.805, p < 0.001). In addition, HALP score was determined to be an independent predictor for short-term mortality (HR, 0.955, 95% CI, 0.945-0.966, p < 0.001).

CONCLUSIONS

HALP score can independently predict the development of no-reflow and short-term mortality in STEMI patients undergoing pPCI.

Evaluating the Neural Underpinnings of Motivation for Walking Exercise

OBJECTIVE

Motivation is critically important for rehabilitation, exercise, and motor performance, but its neural basis is poorly understood. Recent correlational research suggests that the dorsomedial prefrontal cortex (dmPFC) may be involved in motivation for walking activity and/or descending motor output. This study experimentally evaluated brain activity changes in periods of additional motivation during walking exercise and tested how these brain activity changes relate to self-reported exercise motivation and walking speed.

METHODS

Adults without disability (N = 26; 65% women; 25 [standard deviation = 5] years old) performed a vigorous exercise experiment involving 20 trials of maximal speed overground walking. Half of the trials were randomized to include "extra-motivation" stimuli (lap timer, tracked best lap time, and verbal encouragement). Wearable near-infrared spectroscopy measured oxygenated hemoglobin responses from frontal lobe regions, including the dmPFC, primary sensorimotor, dorsolateral prefrontal, anterior prefrontal, supplementary motor, and dorsal premotor cortices.

RESULTS

Compared with standard trials, participants walked faster during extra-motivation trials (2.43 vs 2.67 m/s; P < .0001) and had higher oxygenated hemoglobin responses in all tested brain regions, including dmPFC (+842 vs +1694 μM; P < .0001). Greater dmPFC activity was correlated with more self-determined motivation for exercise between individuals (r = 0.55; P = .004) and faster walking speed between trials (r = 0.18; P = .0002). dmPFC was the only tested brain region that showed both of these associations.

CONCLUSION

Simple motivational stimuli during walking exercise seem to upregulate widespread brain regions. Results suggest that dmPFC may be a key brain region linking affective signaling to motor output.

IMPACT

These findings provide a potential biologic basis for the benefits of motivational stimuli, elicited with clinically feasible methods during walking exercise. Future clinical studies could build on this information to develop prognostic biomarkers and test novel brain stimulation targets for enhancing exercise motivation (eg, dmPFC).

Effect of lipid-based nutrient supplements on micronutrient status and hemoglobin among children with stunting: secondary analysis of a randomized controlled trial in Uganda

BACKGROUND

Micronutrient deficiencies and anemia are widespread among children with stunting.

OBJECTIVES

We assessed the effects of lipid-based nutrient supplements (LNS) containing milk protein (MP) and/or whey permeate (WP) on micronutrient status and hemoglobin (Hb) among children with stunting.

METHODS

This was a secondary analysis of a randomized controlled trial. Children aged 12-59 mo with stunting were randomly assigned to LNS (100 g/d) with milk or soy protein and WP or maltodextrin for 12 wk, or no supplement. Hb, serum ferritin (S-FE), serum soluble transferrin receptor (S-TfR), plasma cobalamin (P-Cob), plasma methylmalonic acid (P-MMA), plasma folate (P-Fol), and serum retinol-binding protein (S-RBP) were measured at inclusion and at 12 wk. Data were analyzed using linear and logistic mixed-effects models.

RESULTS

Among 750 children, with mean age ± SD of 32 ± 11.7 mo, 45% (n = 338) were female and 98% (n = 736) completed follow-up. LNS, compared with no supplementation, resulted in 43% [95% confidence interval (CI): 28, 60] greater increase in S-FE corrected for inflammation (S-FEci), 2.4 (95% CI: 1.2, 3.5) mg/L greater decline in S-TfR, 138 (95% CI: 111, 164) pmol/L greater increase in P-Cob, 33% (95% CI: 27, 39) reduction in P-MMA, and 8.5 (95% CI: 6.6, 10.3) nmol/L greater increase in P-Fol. There was no effect of LNS on S-RBP. Lactation modified the effect of LNS on markers of cobalamin status, reflecting improved status among nonbreastfed and no effects among breastfed children. LNS increased Hb by 3.8 (95% CI: 1.7, 6.0) g/L and reduced the odds of anemia by 55% (odds ratio: 0.45, 95% CI: 0.29, 0.70). MP compared with soy protein increased S-FEci by 14% (95% CI: 3, 26).

CONCLUSIONS

LNS supplementation increases Hb and improves iron, cobalamin, and folate status, but not vitamin A status among children with stunting. LNS should be considered for children with stunting. This trial was registered at ISRCTN as 13093195.

Load carriage physiology in normoxia and hypoxia

PURPOSE

To determine the effects of load carriage in normoxia and normobaric hypoxia on ventilatory responses, hemodynamics, tissue oxygenation, and metabolism.

METHODS

Healthy males (n = 12) completed 3 randomly ordered baseline graded exercise tests in the following conditions: (1) unloaded normoxic (U: FIO2 = 20.93%), (2) loaded (~ 30 kg) normoxic (LN), and (3) loaded hypoxic simulating ~ 3650 m (LH: FIO2 =  ~ 13%). Thereafter, experimental exercise trials were completed in quasi-randomized order (i.e., U completed first) consisting of 3 × 10 min of walking (separated by 5 min seated rest) with stages matched with the U condition (in ascending order) for relative intensity, absolute oxygen consumption ([VO2]; 1.7 L min-1), and walking speed (1.45 ± 0.15 m s-1).

RESULTS

Load carriage increased perceived exertion and reduced VO2max (LN: - 7%; LH: - 32%; p < 0.05). At matched VO2, stroke volume and tidal volume were reduced and maintained with LN and LH vs. U, respectively (p < 0.05). Increases in cardiac output and minute ventilation at matched VO2 (with LH) and speed (with LN and LH), were primarily accomplished via increases in heart rate and breathing frequency (p < 0.05). Cerebral oxygenated hemoglobin (O2HHb) was increased at all intensities with LN, but deoxygenated hemoglobin and total hemoglobin were increased with LH (p < 0.05). Muscle oxygen kinetics and substrate utilization were similar between LN and U, but LH increased CHO dependence and reduced muscle O2HHb at matched speed (p < 0.05).

CONCLUSION

Load carriage reduces cardiorespiratory efficiency and increases physiological strain, particularly in hypoxic environments. Potential load carriage-induced alterations in cerebral blood flow may increase the risk for altitude illnesses and requires further study.

Cold-Water Immersion and Lower Limb Muscle Oxygen Consumption as Measured by Near-Infrared Spectroscopy in Trained Endurance Athletes

CONTEXT

Cold-water immersion (CWI) has been reported to reduce tissue metabolism postimmersion, but physiological data are lacking regarding the muscle metabolic response to its application. Near-infrared spectroscopy (NIRS) is a noninvasive optical technique that can inform muscle hemodynamics and tissue metabolism.

OBJECTIVE

To investigate the effects of CWI at 2 water temperatures (10°C and 15°C) on NIRS-calculated measurements of muscle oxygen consumption (mVO2).

DESIGN

Crossover study.

SETTING

University sports rehabilitation center.

PATIENTS OR OTHER PARTICIPANTS

A total of 11 male National Collegiate Athletic Association Division II long-distance runners (age = 23.4 ± 3.4 years, height = 1.8 ± 0.1 m, mass = 68.8 ± 10.7 kg, mean adipose tissue thickness = 6.7 ± 2.7 mm).

INTERVENTION(S)

Cold-water immersion at 10°C and 15°C for 20 minutes.

MAIN OUTCOME MEASURE(S)

We calculated mVO2 preimmersion and postimmersion at water temperatures of 10°C and 15°C. Changes in tissue oxyhemoglobin (O2Hb), deoxyhemoglobin (HHb), total hemoglobin (tHb), hemoglobin difference (Hbdiff), and tissue saturation index (TSI %) were measured during the 20-minute immersion at both temperatures.

RESULTS

We observed a decrease in mVO2 after immersion at both 10°C and 15°C (F1,9 = 27.7801, P = .001). During the 20-minute immersion at both temperatures, we noted a main effect of time for O2Hb (F3,27 = 14.227, P = .001), HHb (F3,27 = 5.749, P = .009), tHb (F3,27 = 24.786, P = .001), and Hbdiff (F3,27 = 3.894, P = .020), in which values decreased over the course of immersion. Post hoc pairwise comparisons showed that these changes occurred within the final 5 minutes of immersion for tHb and O2Hb.

CONCLUSIONS

A 20-minute CWI at 10°C and 15°C led to a reduction in mVO2. This was greater after immersion at 10°C. The reduction in mVO2 suggests a decrease in muscle metabolic activity (ie, O2 use after CWI). Calculating mVO2 via the NIRS-occlusion technique may offer further insight into muscle metabolic responses beyond what is attainable from observing the NIRS primary signals.

Status of vitamins and minerals in children with screening-identified celiac disease: A case-control study

OBJECTIVES

Micronutrient deficiencies characterize classical "late-diagnosed" celiac disease (CeD). This study aimed to identify the prevalence of micronutrient deficiencies among children with "early-diagnosed" screening-identified CeD to determine the clinical value of routine testing for deficiencies in those patients.

METHODS

A case-control study was conducted on screening-identified CeD patients diagnosed during a mass screening study (84 patients, mean age 11.3 ± 2.6 years). The controls (443 children, mean age 10.8 ± 2.5 years) were negative for celiac disease serological screening. Hemoglobin, serum levels of iron, ferritin, folate, vitamin B12, vitamin A, vitamin E, 25-OH vitamin D, zinc, and selenium were measured.

RESULTS

The mean serum levels of hemoglobin, iron, ferritin, vitamin D, zinc, copper, and selenium were significantly lower in CeD patients than in healthy controls (hemoglobin 12.56 vs. 13.02 g/dL [p = 0.04]; iron 10.61 vs. 17.6 µmol/L [p < 0.001], ferritin 25.7 vs. 48.3 µg/L [p < 0.001], vitamin D 29.1 vs. 37.5 nmol/L, zinc 11.9 vs. 21.7 µmol/L, copper 18.9 vs. 32.5 µmol/L, selenium 1.04 vs. 1.36 µmol/L; p < 0.001). Patients with celiac and severe intestinal damage (Marsh IIIb and IIIc) had significantly lower serum ferritin and vitamin A levels than patients with mild intestinal damage (Marsh II and IIIa) (ferritin 15 vs. 22 µg/L, p < 0.025; vitamin A 0.85 vs. 1.35 µmol/L, p = 0.007).

CONCLUSION

Micronutrient deficiencies are still detectable in "early-diagnosed" screening-identified CeD cases, a clinically relevant result that strongly supports efforts for screening and early diagnosis of CeD.

Trypanosoma cruzi heme responsive gene (TcHRG) plays a central role in orchestrating heme uptake in epimastigotes

Trypanosoma cruzi, a heme auxotrophic parasite, can control intracellular heme content by modulating heme responsive gene (TcHRG) expression when a free heme source is added to an axenic culture. Herein, we explored the role of TcHRG protein in regulating the uptake of heme derived from hemoglobin in epimastigotes. We demonstrate that the endogenous TcHRG (protein and mRNA) responded similarly to bound (hemoglobin) and free (hemin) heme. Endogenous TcHRG was found in the flagellar pocket boundaries and partially overlapping with the mitochondrion. On the other hand, endocytic null parasites were able to develop and exhibited a similar heme content compared to wild-type when fed with hemoglobin, indicating that endocytosis is not the main entrance pathway for hemoglobin-derived heme in this parasite. Moreover, the overexpression of TcHRG led to an increase in heme content when hemoglobin was used as the heme source. Taken together, these results suggest that the uptake of hemoglobin-derived heme likely occurs through extracellular proteolysis of hemoglobin via the flagellar pocket, and this process is governed by TcHRG. In sum, T. cruzi epimastigotes control heme homeostasis by modulating TcHRG expression independently of the available source of heme.

Cryopreserved red blood cells maintain allosteric control of oxygen binding when utilizing trehalose as a cryoprotectant

One of the most common life-saving medical procedures is a red blood cell (RBC) transfusion. Unfortunately, RBCs for transfusion have a limited shelf life after donation due to detrimental storage effects on their morphological and biochemical properties. Inspired by nature, a biomimetics approach was developed to preserve RBCs for long-term storage using compounds found in animals with a natural propensity to survive in a frozen or desiccated state for decades. Trehalose was employed as a cryoprotective agent and added to the extracellular freezing solution of porcine RBCs. Slow cooling (-1 °C min-1) resulted in almost complete hemolysis (1 ± 1 % RBC recovery), and rapid cooling rates had to be used to achieve satisfactory cryopreservation outcomes. After rapid cooling, the highest percentage of RBC recovery was obtained by plunging in liquid nitrogen and thawing at 55 °C, using a cryopreservation solution containing 300 mM trehalose. Under these conditions, 88 ± 8 % of processed RBCs were recovered and retained hemoglobin (14 ± 2 % hemolysis). Hemoglobin's oxygen-binding properties of cryopreserved RBCs were not significantly different to unfrozen controls and was allosterically regulated by 2,3-bisphosphoglycerate. These data indicate the feasibility of using trehalose instead of glycerol as a cryoprotective compound for RBCs. In contrast to glycerol, trehalose-preserved RBCs can potentially be transfused without time-consuming washing steps, which significantly facilitates the usage of cryopreserved transfusible units in trauma situations when time is of the essence.

Prognostic Performance of Hematological and Serum Iron and Metabolite Indices for Detection of Early Iron Deficiency Induced Metabolic Brain Dysfunction in Infant Rhesus Monkeys

BACKGROUND

The current pediatric practice of monitoring for infantile iron deficiency (ID) via hemoglobin (Hgb) screening at one y of age does not identify preanemic ID nor protect against later neurocognitive deficits.

OBJECTIVES

To identify biomarkers of iron-related metabolic alterations in the serum and brain and determine the sensitivity of conventional iron and heme indices for predicting risk of brain metabolic dysfunction using a nonhuman primate model of infantile ID.

METHODS

Simultaneous serum iron and RBC indices, and serum and cerebrospinal fluid (CSF) metabolomic profiles were determined in 20 rhesus infants, comparing iron sufficient (IS; N = 10) and ID (N = 10) infants at 2 and 4 mo of age.

RESULTS

Reticulocyte hemoglobin (RET-He) was lower at 2 wk in the ID group. Significant IS compared with ID differences in serum iron indices were present at 2 mo, but Hgb and RBC indices differed only at 4 mo (P < 0.05). Serum and CSF metabolomic profiles of the ID and IS groups differed at 2 and 4 mo (P < 0.05). Key metabolites, including homostachydrine and stachydrine (4-5-fold lower at 4 mo in ID group, P < 0.05), were altered in both serum and CSF. Iron indices and RET-He at 2 mo, but not Hgb or other RBC indices, were correlated with altered CSF metabolic profile at 4 mo and had comparable predictive accuracy (area under the receiver operating characteristic curve scores, 0.75-0.80).

CONCLUSIONS

Preanemic ID at 2 mo was associated with metabolic alterations in serum and CSF in infant monkeys. Among the RBC indices, only RET-He predicted the future risk of abnormal CSF metabolic profile with a predictive accuracy comparable to serum iron indices. The concordance of homostachydrine and stachydrine changes in serum and CSF indicates their potential use as early biomarkers of brain metabolic dysfunction in infantile ID.

Long-term effects of multiple concussions on prefrontal cortex oxygenation during a hypercapnic challenge in retired contact sport athletes

This exploratory study aimed to investigate the long-term effects of multiple concussions on prefrontal cortex oxygenation during a five-minute hypercapnic challenge using Near Infrared Spectroscopy (NIRS). 55 physically active retired contact sport male athletes with three or more previous concussions (mTBI) were recruited along with 29 physically active males with no concussions history (CTRL). Participants completed five minutes of seated rest prior to the five-minute hypercapnic challenge (20-second breath-hold, 40-second recovery breathing; five times). NIRS measured right and left side oxygenated (O2Hb), deoxygenated (HHb), total (tHb) haemoglobin, and haemoglobin difference (HbDiff) with all parameters analysed through changes in average maximal and minimal values (ΔMAX), Z-scores, and standard deviations. Right prefrontal cortex HbDiff ΔMAX was significantly higher in the mTBI compared to CTRL (p = 0.045) group. Left prefrontal cortex O2Hb ΔMAX (p = 0.040), HHb Z-Scores (p = 0.008), and HbDiff ΔMAX(p = 0.014) were significantly higher in the mTBI group. Within-group right vs left analyses demonstrated significantly lower left HbDiff ΔMAX (p = 0.048) and HbDiff Z-scores (p = 0.002) in the mTBI group, while the CTRL group had significantly lower left HHb Z-scores (p = 0.003) and left tHb Z-scores (p = 0.042). This study provides preliminary evidence that athletes with a history of three or more concussions may have impaired prefrontal cortex oxygenation parameters during a hypercapnic challenge.

Dynamics of hemoglobins during nodule development, nitrate response, and dark stress in Lotus japonicus

Legume nodules express multiple leghemoglobins (Lbs) and non-symbiotic hemoglobins (Glbs), but how they are regulated is unclear. Here, we study the regulation of all Lbs and Glbs of Lotus japonicus in different physiologically relevant conditions and mutant backgrounds. We quantified hemoglobin expression, localized reactive oxygen species (ROS) and nitric oxide (NO) in nodules, and deployed mutants deficient in Lbs and in the transcription factors NLP4 (associated with nitrate sensitivity) and NAC094 (associated with senescence). Expression of Lbs and class 2 Glbs was suppressed by nitrate, whereas expression of class 1 and 3 Glbs was positively correlated with external nitrate concentrations. Nitrate-responsive elements were found in the promoters of several hemoglobin genes. Mutant nodules without Lbs showed accumulation of ROS and NO and alterations of antioxidants and senescence markers. NO accumulation occurred by a nitrate-independent pathway, probably due to the virtual disappearance of Glb1-1 and the deficiency of Lbs. We conclude that hemoglobins are regulated in a gene-specific manner during nodule development and in response to nitrate and dark stress. Mutant analyses reveal that nodules lacking Lbs experience nitro-oxidative stress and that there is compensation of expression between Lb1 and Lb2. They also show modulation of hemoglobin expression by NLP4 and NAC094.

Paraspinal muscle oxygenation and mechanical efficiency are reduced in individuals with chronic low back pain

This study aimed to compare the systemic and local metabolic responses during a 5-min trunk extension exercise in individuals with chronic low back pain (CLBP) and in healthy individuals. Thirteen active participants with CLBP paired with 13 healthy participants performed a standardised 5-min trunk extension exercise on an isokinetic dynamometer set in continuous passive motion mode. During exercise, we used near-infrared spectroscopy to measure tissue oxygenation (TOI) and total haemoglobin-myoglobin (THb). We used a gas exchange analyser to measure breath-by-breath oxygen consumption (V̇O2) and carbon dioxide produced (V̇CO2). We also calculated mechanical efficiency. We assessed the intensity of low back pain sensation before and after exercise by using a visual analogue scale. In participants with CLBP, low back pain increased following exercise (+ 1.5 units; p < 0.001) and THb decreased during exercise (- 4.0 units; p = 0.043). Paraspinal muscle oxygenation (65.0 and 71.0%, respectively; p = 0.009) and mechanical efficiency (4.7 and 5.3%, respectively; p = 0.034) were both lower in participants with CLBP compared with healthy participants. The increase in pain sensation was related to the decrease in tissue oxygenation (R2 = - 0.420; p = 0.036). Decreases in total haemoglobin-myoglobin and mechanical efficiency could involve fatigability in exercise-soliciting paraspinal muscles and, therefore, exacerbate inabilities in daily life. Given the positive correlation between tissue oxygenation and exercise-induced pain exacerbation, muscle oxygenation may be related to persisting and crippling low back pain.

Prevalence and correlates of childhood anemia in the MINA-Brazil birth cohort study

OBJECTIVE

This study aimed to describe the prevalence and predictors of childhood anemia in an Amazonian population-based birth cohort study.

METHODS

Prevalence of maternal anemia was estimated at delivery (hemoglobin [Hb] concentration < 110 g/L) in women participating in the MINA-Brazil birth cohort study and in their children, examined at ages one, two (Hb < 110 g/L), and five (Hb < 115 g/L). Moreover, ferritin, soluble transferrin receptor, and C-reactive protein concentrations were measured in mothers at delivery and in their 1- and 2-year-old children to estimate the prevalence of iron deficiency and its contribution to anemia, while adjusting for potential confounders by multiple Poisson regression analysis (adjusted relative risk [RRa]).

RESULTS

The prevalence 95% confidence interval (CI) of maternal anemia, iron deficiency, and iron-deficiency anemia at delivery were 17.3% (14.0-21.0%), 42.6% (38.0-47.2%), and 8.7% (6.3-11.6)%, respectively (n = 462). At one year of age (n = 646), 42.2% (38.7-45.8%) of the study children were anemic, 38.4% (34.6-42.3%) were iron-deficient, and 26.3 (23.0-29.9) had iron-deficiency anemia. At two years of age (n = 761), these values decreased to 12.8% (10.6-15.2%), 18.1% (15.5-21.1%), and 4.1% (2.8-5.7%), respectively; at five years of age (n = 655), 5.2% (3.6-7.2%) were anemic. Iron deficiency (RRa = 2.19; 95%CI: 1.84-2.60) and consumption of ultra-processed foods (UPF) (RRa = 1.56; 95%CI: 1.14-2.13) were significant contributors to anemia at 1 year, after adjusting for maternal schooling. At 2 years, anemia was significantly associated with maternal anemia at delivery (RRa: 1.67; 95%CI: 1.17-2.39), malaria since birth (2.25; 1.30-3.87), and iron deficiency (2.15; 1.47-3.15), after adjusting for children's age and household wealth index.

CONCLUSIONS

Anemia continues to be highly prevalent during pregnancy and early childhood in the Amazon. Public health policies should address iron deficiency, UPF intake, maternal anemia, and malaria to prevent and treat anemia in Amazonian children.

Immune responses to P falciparum antibodies in symptomatic malaria patients with variant hemoglobin genotypes in Ghana

BACKGROUND

Haemoglobin (Hb) variants such as sickle cell trait (SCT/HbAS) play a role in protecting against clinical malaria, but little is known about the development of immune responses against malaria parasite (Plasmodium falciparum surface protein 230 (Pfs230) and Plasmodium falciparum erythrocyte binding antigen 175 region-3 (PfEBA175-3R)) and vector (on the An. gambiae Salivary Gland Protein-6 peptide 1 (gSG6-P1)) antigens in individuals with variants Hb genotypes. This study assessed antibody (IgG) responses against malaria parasite, Pfs230 and PfEBA175-3R and vector, gSG6-P1 in febrile individuals with variant Hb genotypes.

METHODS

The study was conducted on symptomatic malaria patients attending various healthcare facilities throughout Ghana. Microscopy and ELISA were used to determine the natural IgG antibody levels of gSG6-P1, PfEBA175-3R & Pfs230, and Capillarys 2 Flex Piercing was used for Hb variants determination.

RESULTS

Of the 600 symptomatic malaria patients, 50.0% of the participants had malaria parasites by microscopy. The majority 79.0% (398/504) of the participants had Hb AA, followed by HbAS variant at 11.3% (57/504) and HbAC 6.7% (34/504). There were significantly (p < 0.0001) reduced levels of gSG6-P1 IgG in individuals with both HbAC and HbAS genotypes compared to the HbAA genotype. The levels of gSG6-P1 IgG were significantly (p < 0.0001) higher in HbAS compared to HbAC. Similarly, Pfs230 IgG and PfEBA-175-3R IgG distributions observed across the haemoglobin variants were significantly higher in HbAC relative to HbAS.

CONCLUSION

The study has shown that haemoglobin variants significantly influence the pattern of anti-gSG6-P1, Pfs230, and PfEBA-175 IgG levels in malaria-endemic population. The HbAS genotype is suggested to confer protection against malaria infection. Reduced exposure to infection ultimately reduces the induction of antibodies targeted against P. falciparum antigens.

Effect of Floss Band on Anaerobic Exercise and Muscle Tissue Oxygenation

CONTEXT

Flossing is still a relatively new technique that has yielded varied results in the research literature; therefore, it requires further investigation. Previous research has shown that thigh tissue flossing might improve performance in countermovement jump, sprint time, maximum voluntary contraction, and rate of force development.

DESIGN

The present study aims to investigate the effect of the floss band on performance during the Wingate test (30-WAT), muscle oxygen saturation (SpO2), and total hemoglobin in vastus lateralis.

METHODS

Twenty-two students of physical education and sport (11 men and 11 women) were randomly selected to complete either the Wingate test with the application of a floss band in warm-up or the Wingate test without the use of a floss band, followed by the alternative 24 hours apart.

RESULTS

Throughout the testing, the floss band did not affect performance values during the Wingate test (relative peak power, relative average power, and fatigue index). However, there was a medium to large effect difference during 1 minute prior to 30-WAT (PRE), during the 30-WAT, and 10-minute recovery (REC) in values of SpO2 and total hemoglobin. Use of floss band displayed a higher SpO2 during PRE, 30-WAT, and REC by ∼13.55%, d < 2; ∼19.06%, d = 0.89; and ∼8.55%, d = 0.59, respectively.

CONCLUSION

Collectively, these findings indicate that the application of thigh flossing during warm-up has no effect on 30-WAT performance; however, SpO2 was significantly increased in all stages of testing. This could lead to potential improvement in repeated anaerobic exercise due to increased blood flow. Increased muscle oxygen saturation can also lead to improved tissue healing as oxygen supply is essential for tissue repair, wound healing, and pain management.

Cerebral hemodynamics and oxygenation in adult patients with sickle cell disease after stem cell transplantation

Sickle cell disease (SCD) is characterized by chronic hemolytic anemia associated with impaired cerebral hemodynamics and oxygen metabolism. Hematopoietic stem cell transplantation (HSCT) is currently the only curative treatment for patients with SCD. Whereas normalization of hemoglobin levels and hemolysis markers has been reported after HSCT, its effects on cerebral perfusion and oxygenation in adult SCD patients remain largely unexplored. This study investigated the effects of HSCT on cerebral blood flow (CBF), oxygen delivery, cerebrovascular reserve (CVR), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2 ) in 17 adult SCD patients (mean age: 25.0 ± 8.0, 6 females) before and after HSCT and 10 healthy ethnicity-matched controls (mean age: 28.0 ± 8.8, 6 females) using MRI. For the CVR assessment, perfusion scans were performed before and after acetazolamide as a vasodilatory stimulus. Following HSCT, gray and white matter (GM and WM) CBF decreased (p < .01), while GM and WM CVR increased (p < .01) compared with the baseline measures. OEF and CMRO2 also increased towards levels in healthy controls (p < .01). The normalization of cerebral perfusion and oxygen metabolism corresponded with a significant increase in hemoglobin levels and decreases in reticulocytes, total bilirubin, and LDH as markers of hemolysis (p < .01). This study shows that HSCT results in the normalization of cerebral perfusion and oxygen metabolism, even in adult patients with SCD. Future follow-up MRI scans will determine whether the observed normalization of cerebral hemodynamics and oxygen metabolism prevents new silent cerebral infarcts.

A randomized, controlled, open label non-inferiority trial of intravenous ferric carboxymaltose versus iron sucrose in patients with iron deficiency anemia in China

Iron deficiency (ID) and ID anemia (IDA) pose significant public health concerns in China. Although iron sucrose (IS) treatment is well-established in the country, ferric carboxymaltose (FCM) offers the advantage of higher doses and fewer infusions. This open label, randomized, controlled, non-inferiority trial was conducted at multiple sites in China to compare the outcomes of FCM (maximum of 2 doses, 500 or 1000 mg iron) and IS (up to 11 infusions, 200 mg iron) treatments in subjects with IDA. The primary endpoint was the achievement of hemoglobin (Hb) response (an increase of ⩾2 g/dL from baseline) within 8 weeks, whereas secondary endpoints included changes in Hb, transferrin saturation, and serum ferritin levels. Among the 371 randomized subjects, a similar percentage of subjects treated with FCM and IS achieved Hb-response (FCM 99.4%, IS 98.3%), thereby confirming the non-inferiority of FCM compared with IS (difference 1.12 (-2.15, 4.71; 95% confidence interval (CI))). Furthermore, a significantly higher proportion of FCM-treated subjects achieved early Hb-response at Week 2 (FCM 85.2%, IS 73.2%; difference 12.1 (3.31, 20.65; 95% CI)). Additionally, the increase in TSAT and serum ferritin levels from baseline was significantly greater at all time points for FCM-treated subjects. The safety profiles of FCM and IS were comparable, with the exception of transient hypophosphatemia and pyrexia, which are consistent with FCM's known safety profile. In conclusion, FCM proves to be an efficacious treatment for IDA, providing faster Hb-response and correction of ID with fewer administrations than IS.

The iron status of rural Nigerian women in the second and third trimesters of pregnancy: implications for the iron endowment and subsequent dietary iron needs of their babies

INTRODUCTION

The aim of the study was to determine the iron status of rural-dwelling pregnant Nigerian women in the second and third trimesters, and to predict their risk of giving birth to babies with suboptimal iron endowment.

METHODS

This was a prospective cohort study conducted between April and August 2021. A total of 174 consecutive and consenting pregnant rural dwellers, who met the inclusion criteria, were recruited by convenience sampling from the antenatal clinic of a public hospital in Nsukka, a semirural town in south-east Nigeria. The study participants were aged 21-40 years, and their iron status was determined by measuring blood haemoglobin (Hb) and serum ferritin (SF) concentration. Hb concentration was determined by the cyanmethemoglobin method and the SF concentration was determined by enzyme immunoassay method.

RESULTS

Almost half (47.7%) of the participants had Hb concentrations below 11 g/dL, while about two out of every five (40.8%) had SF concentrations less than 15 µg/L. The prevalence of iron deficiency, iron deficiency anaemia (IDA) and non-iron deficiency anaemia were 40.8%, 23.6% and 24.7%, respectively. The mean SF levels varied with maternal age, gestation stage, pregnancy intervals and the intake of iron supplements. The mean SF concentration was higher in the second trimester than in the third. The mean SF concentration ± standard deviation (37.10±3.02 µg/L) was higher in the group that took iron supplements than in the group that did not (20.76±2.11 µg/L). However, two out of five participants in both groups had SF concentrations less than 15.0 µg/L.

CONCLUSION

The prevalence of IDA was quite high among the participants in both trimesters even with the widespread intake of the recommended oral iron supplements. About four out of 10 of the participants had SF concentrations of less than 15 µg/L and were thus judged at risk of giving birth to babies with poor iron deposits. Therefore, more effective strategies are needed to monitor and prevent IDA among pregnant women in rural populations of Nigeria and, by inference, other parts of tropical Africa.

Muscle deoxygenation during ramp incremental cycle exercise in older adults with type 2 diabetes

PURPOSE

To explore profiles of fractional O2 extraction (using near-infrared spectroscopy) during ramp incremental cycling in older individuals with type 2 diabetes (T2D).

METHODS

Twelve individuals with T2D (mean ± SD, age: 63 ± 3 years) and 12 healthy controls (mean age: 65 ± 3 years) completed a ramp cycling exercise. Rates of muscle deoxygenation (i.e., deoxygenated haemoglobin and myoglobin, Δ[HHb + Mb]) profiles of the vastus lateralis muscle were normalised to 100% of the response, plotted against absolute (W) and relative (%peak) power output (PO) and fitted with a double linear regression model.

RESULTS

Peak oxygen uptake (V̇O2peak) was significantly (P < 0.01) reduced in T2D (23.0 ± 4.2 ml.kg-1.min-1) compared with controls (28.3 ± 5.3 ml.kg-1.min-1). The slope of the first linear segment of the model was greater (median (interquartile range)) in T2D (1.06 (1.50)) than controls (0.79 (1.06)) when Δ%[HHb + Mb] was plotted as a function of PO. In addition, the onset of the second linear segment of the Δ%[HHb + Mb]/PO model occurred at a lower exercise intensity in T2D (101 ± 35 W) than controls (140 ± 34 W) and it displayed a near-plateau response in both groups. When the relationship of the Δ%[HHb + Mb] profile was expressed as a function of %PO no differences were observed in any parameters of the double linear model.

CONCLUSIONS

These findings suggest that older individuals with uncomplicated T2D demonstrate greater fractional oxygen extraction for a given absolute PO compared with older controls. Thus, the reductions in V̇O2peak in older people with T2D are likely influenced by impairments in microvascular O2 delivery.

Analysis of anemia and iron supplementation among glioblastoma patients reveals sex-biased association between anemia and survival

The association between anemia and outcomes in glioblastoma patients is unclear. We analyzed data from 1346 histologically confirmed adult glioblastoma patients in the TriNetX Research Network. Median hemoglobin and hematocrit levels were quantified for 6 months following diagnosis and used to classify patients as anemic or non-anemic. Associations of anemia and iron supplementation of anemic patients with median overall survival (median-OS) were then studied. Among 1346 glioblastoma patients, 35.9% of male and 40.5% of female patients were classified as anemic using hemoglobin-based WHO guidelines. Among males, anemia was associated with reduced median-OS compared to matched non-anemic males using hemoglobin (HR 1.24; 95% CI 1.00-1.53) or hematocrit-based cutoffs (HR 1.28; 95% CI 1.03-1.59). Among females, anemia was not associated with median-OS using hemoglobin (HR 1.00; 95% CI 0.78-1.27) or hematocrit-based cutoffs (HR: 1.10; 95% CI 0.85-1.41). Iron supplementation of anemic females trended toward increased median-OS (HR 0.61; 95% CI 0.32-1.19) although failing to reach statistical significance whereas no significant association was found in anemic males (HR 0.85; 95% CI 0.41-1.75). Functional transferrin-binding assays confirmed sexually dimorphic binding in resected patient samples indicating underlying differences in iron biology. Anemia among glioblastoma patients exhibits a sex-specific association with survival.

High Ferritin Is Not Needed in Hemodialysis Patients: A Retrospective Study of Total Body Iron and Oral Iron Replacement Therapy

In vivo iron levels can be adjusted through intestinal iron absorption to be maintained at a suitable level; however, optimal iron levels in hemodialysis (HD) patients are unclear. In this study, we investigated total body iron (TBI), calculated as the sum of red blood cell (RBC) iron and iron stores, during courses of low-dose oral iron replacement therapy, and evaluated in vivo iron sufficiency and its indicators in HD patients. We analyzed data on 105 courses of low-dose iron replacement therapy administered to 83 patients on maintenance HD over 7 months. We evaluated changes in TBI, RBC iron, and iron stores from the initiation of treatment to month 7 in two groups of patients, namely, iron-therapy responders and non-responders. TBI showed significant increases until month 4 and plateaued thereafter in iron-therapy responders, and tended to increase and then reached a similar plateau in non-responders (month 7: 1900 ± 447 vs. 1900 ± 408 mg). Steady-state TBI was strongly correlated with body surface area (y = 1628.6x - 791.91, R2 = 0.88, p < 0.001). We observed constant TBI during oral iron replacement therapy suggesting the activation of a "mucosal block". The results suggest that body surface area has utility for estimating the required TBI with regression equations.

Blood-stage antimalarial activity, favourable metabolic stability and in vivo toxicity of novel piperazine linked 7-chloroquinoline-triazole conjugates

The persistence of drug resistance poses a significant obstacle to the advancement of efficacious malaria treatments. The remarkable efficacy displayed by 1,2,3-triazole-based compounds against Plasmodium falciparum highlights the potential of triazole conjugates, with diverse pharmacologically active structures, as potential antimalarial agents. We aimed to synthesize 7-dichloroquinoline-triazole conjugates and their structure-activity relationship (SAR) derivatives to investigate their anti-plasmodial activity. Among them, QP11, featuring a m-NO2 substitution, demonstrated efficacy against both chloroquine-sensitive and -resistant parasite strains. QP11 selectively inhibited FP2, a cysteine protease involved in hemoglobin degradation, and showed synergistic effects when combined with chloroquine. Additionally, QP11 hindered hemoglobin degradation and hemozoin formation within the parasite. Metabolic stability studies indicated high stability of QP11, making it a promising antimalarial candidate. In vivo evaluation using a murine malaria model demonstrated QP11's efficacy in eradicating parasite growth without neurotoxicity, presenting it as a promising compound for novel antimalarial development.

Endogenously produced H2O2 is intimately involved in iron metabolism in Streptococcus pneumoniae

IMPORTANCE

Heme degradation provides pathogens with growth essential iron, leveraging on the host heme reservoir. Bacteria typically import and degrade heme enzymatically, and here, we demonstrated a significant deviation from this dogma. We found that Streptococcus pneumoniae liberates iron from met-hemoglobin extracellularly, in a hydrogen peroxide (H2O2)- and cell-dependent manner; this activity serves as a major iron acquisition mechanism for S. pneumoniae. Inhabiting oxygen-rich environments is a major part of pneumococcal biology, and hence, H2O2-mediated heme degradation likely supplies iron during infection. Moreover, H2O2 reaction with ferrous hemoglobin but not with met-hemoglobin is known to result in heme breakdown. Therefore, the ability of pneumococci to degrade heme from met-hemoglobin is a new paradigm. Lastly, this study will inform other research as it demonstrates that extracellular degradation must be considered in the interpretations of experiments in which H2O2-producing bacteria are given heme or hemoproteins as an iron source.

The emerging roles of nitric oxide and its associated scavengers-phytoglobins-in plant symbiotic interactions

A key feature in the establishment of symbiosis between plants and microbes is the maintenance of the balance between the production of the small redox-related molecule, nitric oxide (NO), and its cognate scavenging pathways. During the establishment of symbiosis, a transition from a normoxic to a microoxic environment often takes place, triggering the production of NO from nitrite via a reductive production pathway. Plant hemoglobins [phytoglobins (Phytogbs)] are a central tenant of NO scavenging, with NO homeostasis maintained via the Phytogb-NO cycle. While the first plant hemoglobin (leghemoglobin), associated with the symbiotic relationship between leguminous plants and bacterial Rhizobium species, was discovered in 1939, most other plant hemoglobins, identified only in the 1990s, were considered as non-symbiotic. From recent studies, it is becoming evident that the role of Phytogbs1 in the establishment and maintenance of plant-bacterial and plant-fungal symbiosis is also essential in roots. Consequently, the division of plant hemoglobins into symbiotic and non-symbiotic groups becomes less justified. While the main function of Phytogbs1 is related to the regulation of NO levels, participation of these proteins in the establishment of symbiotic relationships between plants and microorganisms represents another important dimension among the other processes in which these key redox-regulatory proteins play a central role.

Hemoglobin Protects Enamel against Intrinsic Enamel Erosive Demineralization

INTRODUCTION

This study investigated the changes in the acquired enamel pellicle (AEP) proteome when this integument is formed in vivo after treatment with sugarcane-derived cystatin (CaneCPI-5), hemoglobin (HB), and a statherin-derived peptide (StN15), or their combination and then exposed to an intrinsic acid challenge. The effectiveness of these treatments in preventing intrinsic erosion was also evaluated.

METHODS

Ten volunteers, after prophylaxis, in 5 crossover phases, rinsed with the following solutions (10 mL, 1 min): control (deionized water-H2O) - group 1, 0.1 mg/mL CaneCPI-5 - group 2, 1.0 mg/mL HB - group 3, 1.88 × 10-5M StN15 - group 4, or a blend of these - group 5. Following this, AEP formation occurred (2 h) and an enamel biopsy (10 µL, 0.01 m HCl, pH 2.0, 10 s) was conducted on one incisor. The biopsy acid was then analyzed for calcium (Arsenazo method). The vestibular surfaces of the other teeth were treated with the same acid. Acid-resistant proteins in the residual AEP were then collected and analyzed quantitatively via proteomics.

RESULTS

Compared to control, treatment with the proteins/peptide, mixed or isolated, markedly enhanced acid-resistant proteins in the AEP. Notable increases occurred in pyruvate kinase PKM (11-fold, CaneCPI-5), immunoglobulins and submaxillary gland androgen-regulated protein 3B (4-fold, StN15), Hb, and lysozyme C (2-fold, StN15). Additionally, a range of proteins not commonly identified in the AEP but known to bind calcium or other proteins were identified in groups treated with the tested proteins/peptide either in isolation or as a mixture. The mean (SD, mM) calcium concentrations released from enamel were 3.67 ± 1.48a, 3.11 ± 0.72a, 1.94 ± 0.57b, 2.37 ± 0.90a, and 2.38 ± 0.45a for groups 1-5, respectively (RM-ANOVA/Tukey, p < 0.05).

CONCLUSIONS

Our findings demonstrate that all treatments, whether using a combination of proteins/peptides or in isolation, enhanced acid-resistant proteins in the AEP. However, only HB showed effectiveness in protecting against intrinsic erosive demineralization. These results pave the way for innovative preventive methods against intrinsic erosion, using "acquired pellicle engineering" techniques.

Intravenous iron versus blood transfusion for postpartum anemia: a systematic review and meta-analysis

BACKGROUND

Intravenous iron (IV-iron) is used as an alternative to, or alongside, red blood cell transfusion (RBC-T) to treat more severe postpartum anemia (PPA), although optimal treatment options remain unclear. No previous systematic reviews have examined IV-iron and RBC-T, including patient-reported outcomes and hematological responses.

METHODS

A systematic review and meta-analysis of randomized trials comparing IV-iron and RBC-T with each other, oral iron, no treatment, and placebo for the treatment of PPA. Key inclusion criteria were PPA (hemoglobin < 12 g/dL) and IV-iron or RBC-T as interventions. Key exclusion criteria were antenatal IV-iron or RBC-T. Fatigue was the primary outcome. Secondary outcomes included hemoglobin and ferritin concentrations, and adverse events. From 27th August 2020 to 26th September 2022, databases, registries, and hand searches identified studies. A fixed-effect meta-analysis was undertaken using RevMan (5.4) software. The quality of the studies and the evidence was assessed using the Cochrane Risk of Bias table, and Grading of Recommendations, Assessment, Development, and Evaluation. This review is registered with the Prospective Register of Systematic Reviews (CRD42020201115).

RESULTS

Twenty studies and 4196 participants were included: 1834 assigned IV-iron, 1771 assigned oral iron, 330 assigned RBC-T, and 261 assigned non-intervention. Six studies reported the primary outcome of fatigue (1251 participants). Only studies of IV-iron vs. oral iron (15 studies) were available for meta-analysis. Of these, three reported on fatigue using different scales; two were available for meta-analysis. There was a significant reduction in fatigue with IV-iron compared to oral iron (standardized mean difference - 0.40, 95% confidence interval (CI) - 0.62, - 0.18, I2 = 0%). The direction of effect also favored IV-iron for hemoglobin (mean difference (MD) 0.54 g/dL, 95% confidence interval (CI) 0.47, 0.61, I2 = 91%), ferritin, (MD 58.07 mcg/L, 95% CI 55.74, 60.41, I2 = 99%), and total adverse events (risk-ratio 0.63, 95% CI 0.52, 0.77, I2 = 84%). The overall quality of the evidence was low-moderate.

DISCUSSION

For all outcomes, the evidence for RBC-T, compared to IV-iron, non-intervention, or dose effects of RBC-T is very limited. Further research is needed to determine whether RBC-T or IV-iron for the treatment of PPA is superior for fatigue and hematological outcomes.

Risk factors for anaemia among women and their young children hospitalised with suspected thiamine deficiency in northern Lao PDR

Anaemia among women and young children remains a major public health concern. This secondary study describes the anaemia prevalence among young hospitalised children and their mothers in northern Lao People's Democratic Republic and explores possible nutritional causes and risk factors for anaemia. Hospitalised children (ages 21 days to <18 months) with clinical symptoms suggestive of thiamine deficiency disorders were eligible along with their mothers. Venous blood was collected for determination of haemoglobin, ferritin, soluble transferrin receptor (sTfR), retinol-binding protein (RBP), erythrocyte glutathione reductase activation coefficient (EGRac), thiamine diphosphate (ThDP) and acute phase proteins. Risk factors for anaemia were modelled using minimally adjusted logistic regression controlling for age. Haemoglobin results were available for 436 women (mean ± SD age 24.7 ± 6.4 years; 1.6% pregnant) and 427 children (4.3 ± 3.5 months; 60.3% male). Anaemia prevalence (Hb < 120 g/L for nonpregnant women and <110 g/L for pregnant women and children) was 30.7% among women and 55.2% among children. In bivariate analyses, biomarkers significantly associated with anaemia in women were ferritin, sTfR, RBP, EGRac and ThDP. Other risk factors for women were lower BMI, mid-upper arm circumference < 23.5 cm, lower education, lower socioeconomic index, food insecurity, Hmong ethnicity, not/rarely having attended antenatal care, not having taken antenatal iron-containing supplements and not meeting minimum dietary diversity. Risk factors for anaemia among children were older age, male sex, stunting, sTfR, ThDP and alpha-1-acid-glycoprotein. Anaemia was common among women and their hospitalised children and was associated with micronutrient deficiencies and socioeconomic, dietary and health care-seeking risk factors, suggesting that multiple strategies are required to prevent anaemia among women and children.

Cell-free hemoglobin triggers macrophage cytokine production via TLR4 and MyD88

Cell-free hemoglobin (CFH) is elevated in the airspace of patients with acute respiratory distress syndrome (ARDS) and is sufficient to cause acute lung injury in a murine model. However, the pathways through which CFH causes lung injury are not well understood. Toll-like receptor 4 (TLR4) is a mediator of inflammation after detection of damage- and pathogen-associated molecular patterns. We hypothesized that TLR4 signaling mediates the proinflammatory effects of CFH in the airspace. After intratracheal CFH, BALBc mice deficient in TLR4 had reduced inflammatory cell influx into the airspace [bronchoalveolar lavage (BAL) cell counts, median TLR4 knockout (KO): 0.8 × 104/mL [IQR 0.4-1.2 × 104/mL], wild-type (WT): 3.0 × 104/mL [2.2-4.0 × 104/mL], P < 0.001] and attenuated lung permeability (BAL protein, TLR4KO: 289 µg/mL [236-320], WT: 488 µg/mL [422-536], P < 0.001). These mice also had attenuated production of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in the airspace. C57Bl/6 mice lacking TLR4 on myeloid cells only (LysM.Cre+/-TLR4fl/fl) had reduced cytokine production in the airspace after CFH, without attenuation of lung permeability. In vitro studies confirm that WT primary murine alveolar macrophages exposed to CFH (0.01-1 mg/mL) had dose-dependent increases in IL-6, IL-1 β, CXC motif chemokine ligand 1 (CXCL-1), TNF-α, and IL-10 (P < 0.001). Murine MH-S alveolar-like macrophages show TLR4-dependent expression of IL-1β, IL-6, and CXCL-1 in response to CFH. Primary alveolar macrophages from mice lacking TLR4 adaptor proteins myeloid differentiation primary response 88 (MyD88) or TIR-domain-containing adapter-inducing interferon-β (TRIF) revealed that MyD88KO macrophages had 71-96% reduction in CFH-dependent proinflammatory cytokine production (P < 0.001), whereas macrophages from TRIFKO mice had variable changes in cytokine responses. These data demonstrate that myeloid TLR4 signaling through MyD88 is a key regulator of airspace inflammation in response to CFH.NEW & NOTEWORTHY Cell-free hemoglobin (CFH) is elevated in the airspace of most patients with acute respiratory distress syndrome and causes severe inflammation. Here, we identify that CFH contributes to macrophage-induced cytokine production via Toll-like receptor 4 (TLR4) and myeloid differentiation primary response 88 (MyD88) signaling. These data increase our knowledge of the mechanisms through which CFH contributes to lung injury and may inform development of targeted therapeutics to attenuate inflammation.

New view on the compatibility of hemoglobin function in the erythrocytes

OBJECTIVE

Aim: To study the process of hemoglobin oxidation and the enzymatic reactions associated with it.

PATIENTS AND METHODS

Materials and Methods: Heparinized human blood (15 IU/ml) was obtained from the clinical department. The concentration of oxy- and methemoglobin, auto-oxidation of hemoglobin was determined spectrophotometrically spectrophotometrically. Autooxidation of hemoglobin was recorded spectrophotometrically, and protein concentration was determined by the Lowry method. Monooxygenase activity of hemoglobin was also measured by the method described by Lowry spectrophotometrically. The concentration of O2 and H2O2 in the reaction media was determined on a biomicroanalyzer OR 210/3 (Redelkis).

RESULTS

Results: The obtained experimental data allow us to propose a mechanism of "spontaneous autooxidation" of oxyhemoglobin, which can be described by the following equations: Hb2+O2 → Hb3+ + O2 - (1) Hb2+O2 + 2e - + 2H+ →Hb3+ + H2O2 (2) Hb2+O2 + 2e - + 2H+ →Hb2+ + H2O2 (3) Hb2+ + O2 →Hb2+O2 (4) Spectral characteristics of the process of "spontaneous auto-oxidation" indicate the formation of a metform of hemoglobin, the depletion of oxygen by the system was established, at pH 5.6, an increase in the monooxygenase activity of hemoglobin is observed 3-4 times compared to the physiological level.

CONCLUSION

Сonclusions: In addition to the main, previously known functions of hemoglobin (gas transport, peroxidase, monooxygenase), it catalyzes a two-electron oxidase reaction in which O2 is reduced to H2O2. This is confirmed by experimental data on the formation of one of the products of "spontaneous autoxidation" of oxyhemoglobin _ deoxyform at pH 5.6 _ 8.9.