Biological and clinical aspects of soluble transferrin receptor

Reference intervals and percentiles for soluble transferrin receptor and sTfR/log ferritin index in healthy children and adolescents

OBJECTIVES

Soluble transferrin receptor (sTfR) is a marker of both erythropoiesis and iron status and is considered useful for detecting iron deficiency, especially in inflammatory conditions, but reference intervals covering the entire pediatric age spectrum are lacking.

METHODS

We studied 1,064 (48.5 % female) healthy children of the entire pediatric age spectrum to determine reference values and percentiles for sTfR and the ratio of sTfR to log-ferritin (sTfR-F index) using a standard immunoturbidimetric assay.

RESULTS

Soluble TfR levels were highly age-specific, with a peak in infancy and a decline in adulthood, whereas the sTfR-F index was a rather constant parameter. There were positive linear relationships for sTfR with hemoglobin (Hb) (p=0.008) and transferrin (females p<0.001; males p=0.003). A negative association was observed between sTfR and ferritin in females (p<0.0001) and for transferrin saturation and mean corpuscular volume (MCV) in both sexes (both p<0.0001). We found a positive relationship between sTfR and body height, body mass index (BMI) and inflammatory markers (CrP p<0.0001; WBC p=0.0172), while sTfR-F index was not affected by inflammation.

CONCLUSIONS

Soluble TfR values appear to reflect the activity of infant erythropoiesis and to be modulated by inflammation and iron deficiency even in a healthy cohort.

Anemia of Chronic Kidney Disease-A Narrative Review of Its Pathophysiology, Diagnosis, and Management

Anemia is one of the most common chronic kidney disease (CKD) complications. It negatively affects patients' quality of life and clinical outcomes. The pathophysiology of anemia in CKD involves the interplay of various factors such as erythropoietin (EPO) deficiency, iron dysregulation, chronic inflammation, bone marrow dysfunction, and nutritional deficiencies. Despite recent advances in understanding this condition, anemia still remains a serious clinical challenge in population of patients with CKD. Several guidelines have been published with the aim to systematize the diagnostic approach and treatment of anemia; however, due to emerging data, many recommendations vary between publications. Recent studies indicate a potential of novel biomarkers to evaluate anemia and related conditions such as iron deficiency, which is often present in CKD patients. Our article aims to summarize the pathophysiology of anemia in CKD, as well as the diagnosis and management of this condition, including novel therapeutic approaches such as hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHI). Understanding these complex subjects is crucial for a targeted approach to diagnose and treat patients with anemia in CKD effectively.

Association of Serum Soluble Transferrin Receptor Concentration With Markers of Inflammation: Analysis of 1001 Patients From a Tertiary Rheumatology Center

OBJECTIVE

Soluble transferrin receptor (sTfR) is considered to be a useful biomarker for the diagnosis of iron deficiency, especially in the setting of inflammation, as it is thought to not be affected by inflammation. We analyzed the relationship between sTfR levels and inflammatory markers in patients with known or suspected inflammatory rheumatic disease (IRD).

METHODS

Blood samples of 1001 patients with known or suspected IRD referred to a tertiary rheumatology center were analyzed. Study participants were classified as patients with active IRD and patients with inactive IRD or without IRD. Correlation analyses were used to explore the relationship between sTfR levels and inflammatory markers (ie, C-reactive protein [CRP], erythrocyte sedimentation rate [ESR]). We applied multiple linear regression analysis to evaluate the predictive value of CRP levels for sTfR concentrations after adjustment for potential confounding factors.

RESULTS

There were positive correlations between inflammatory markers (CRP, ESR) and serum sTfR levels (ρ 0.44, ρ 0.43, respectively; P < 0.001), exceeding the strength of correlation between inflammatory markers and the acute phase reactant ferritin (ρ 0.30, ρ 0.23, respectively; P < 0.001). Patients with active IRD demonstrated higher serum sTfR levels compared to patients with inactive or without IRD (mean 3.99 [SD 1.69] mg/L vs 3.31 [SD 1.57] mg/L; P < 0.001). After adjustment for potential confounding factors, CRP levels are predictive for serum sTfR concentrations (P < 0.001).

CONCLUSION

The study provides evidence against the concept that sTfR is a biomarker not affected by inflammation.

Association of soluble transferrin receptor/log ferritin index with all-cause and cause-specific mortality: National Health and Nutrition Examination Survey

Background

Soluble transferrin receptor (sTfR)/log ferritin index (sTfR Index) can be used to assess the entire spectrum of iron status, and is valuable in evaluating iron status in population studies. There is still a lack of evidence on the association between sTfR index and all-cause mortality.

Object

To explore the association between sTfR index and all-cause mortality, as well as mortality due to cardiovascular disease (CVD) and cancer.

Method

Data were from the National Health and Nutrition Examination Survey (NHANES) between 2003 to 2020. Participants aged 16 years and older who had complete data of serum ferritin and sTfR were included. Pregnant individuals or those with ineligible data on death or follow-up were excluded from the analysis. Baseline sTfR index was calculated by baseline sTfR/log (ferritin) and classified as three tertile. We performed the Cox proportional hazard regression to assess the association of sTfR index (both continuous and categorical scale) with all-cause and cause-specific mortality and further assess the non-linear relationship between sTfR index and the outcomes with restricted cubic spline.

Result

In this study, 11,525 participants, a total of 231 (2.0%) all-cause deaths occurred during a median follow-up of 51 months. The risk of all-cause mortality, CVD-related mortality, and cancer-related mortality was higher in participants with highest tertile of sTfR index. After confounding factors adjustment, participants with highest tertile of sTfR index were associated with an increased risk of all-cause mortality (HR: 1.71, 95% CI: 1.14-2.57) as compared with lowest tertile. Additionally, sTfR index per SD increment was associated with a 25% increasing risk of all-cause mortality (HR: 1.25, 95% CI: 1.08-1.45, p = 0.003) and a 38% cancer-related mortality (HR: 1.38, 95% CI: 1.07-1.77, p = 0.018). These associations remained robust after adjusting for the serum ferritin as well as in various subgroups stratified by age, sex, smoking statue, hypertension, diabetes, and CVD. Spline analysis showed that there is approximately linear relationship between sTfR index with all-cause mortality (p for non-linear = 0.481). Moreover, ferritin was not a predictor of all-cause death after adjustment for confounding factors.

Significance

This cohort study demonstrated a significant association between sTfR index increment and an increased risk of all-cause and cancer-related mortality, independent of ferritin levels.

Diagnostic performance of automated red cell parameters in predicting bone marrow iron stores

OBJECTIVES

The aim of the study was to determine the diagnostic performance of novel automated red cell parameters for estimating bone marrow iron stores.

METHODS

The study was a retrospective single-centre study based on data from an automated haematology analyser and results of bone marrow iron staining. Red cell parameters were measured on a Sysmex XN-series haematology analyser. Bone marrow iron stores were assessed semiquantitatively by cytochemical reaction according to Perls.

RESULTS

The analysis included 429 bone marrow aspirate smears from 393 patients. Median age of patients was 67 years, 52 % of them were female. The most common indication for bone marrow examination was a plasma cell dyscrasia (n=104; 24 %). Median values of percentage of hypochromic and hyperchromic red blood cells (%HYPO-He, %HYPER-He), reticulocyte haemoglobin equivalent (RET-He) and microcytic red blood cells (MicroR) were statistically significantly different between cases with iron deplete and iron replete bone marrow. In a logistic regression model, ferritin was the best predictor of bone marrow iron stores (AUC=0.891), outperforming RET-He and %HYPER-He (AUC=0.736 and AUC=0.722, respectively). In a combined model, ferritin/MicroR index achieved the highest diagnostic accuracy (AUC=0.915), outperforming sTfR/log ferritin index (AUC=0.855).

CONCLUSIONS

While single automated red cell parameters did not show improved diagnostic accuracy when compared to traditional iron biomarkers, a novel index ferritin/MicroR has the potential to outperform ferritin and sTfR/log ferritin index for predicting bone marrow iron stores. Further research is needed for interpretation and implementation of novel parameters and indices, especially in the context of unexplained anaemia and myelodysplastic syndromes.

Emerging significance and therapeutic targets of ferroptosis: a potential avenue for human kidney diseases

Kidney diseases remain one of the leading causes of human death and have placed a heavy burden on the medical system. Regulated cell death contributes to the pathology of a plethora of renal diseases. Recently, with in-depth studies into kidney diseases and cell death, a new iron-dependent cell death modality, known as ferroptosis, has been identified and has attracted considerable attention among researchers in the pathogenesis of kidney diseases and therapeutics to treat them. The majority of studies suggest that ferroptosis plays an important role in the pathologies of multiple kidney diseases, such as acute kidney injury (AKI), chronic kidney disease, and renal cell carcinoma. In this review, we summarize recently identified regulatory molecular mechanisms of ferroptosis, discuss ferroptosis pathways and mechanisms of action in various kidney diseases, and describe the protective effect of ferroptosis inhibitors against kidney diseases, especially AKI. By summarizing the prominent roles of ferroptosis in different kidney diseases and the progress made in studying ferroptosis, we provide new directions and strategies for future research on kidney diseases. In summary, ferroptotic factors are potential targets for therapeutic intervention to alleviate different kidney diseases, and targeting them may lead to new treatments for patients with kidney diseases.

Nutritional Aspects of Iron in Health and Disease

Dietary iron assimilation is critical for health and essential to prevent iron-deficient states and related comorbidities, such as anemia. The bioavailability of iron is generally low, while its absorption and metabolism are tightly controlled to satisfy metabolic needs and prevent toxicity of excessive iron accumulation. Iron entry into the bloodstream is limited by hepcidin, the iron regulatory hormone. Hepcidin deficiency due to loss-of-function mutations in upstream gene regulators causes hereditary hemochromatosis, an endocrine disorder of iron overload characterized by chronic hyperabsorption of dietary iron, with deleterious clinical complications if untreated. The impact of high dietary iron intake and elevated body iron stores in the general population is not well understood. Herein, we summarize epidemiological data suggesting that a high intake of heme iron, which is abundant in meat products, poses a risk factor for metabolic syndrome pathologies, cardiovascular diseases, and some cancers. We discuss the clinical relevance and potential limitations of data from cohort studies, as well as the need to establish causality and elucidate molecular mechanisms.

Association of Body Iron Metabolism with Type 2 Diabetes Mellitus in Chinese Women of Childbearing Age: Results from the China Adult Chronic Disease and Nutrition Surveillance (2015)

High iron stores have been reported to be associated with type 2 diabetes mellitus (T2DM). However, evidence for the associations of iron metabolism with T2DM is inconsistent, and whether there is a threshold effect remains controversial. In the present study, we aimed to examine the associations between various iron biomarkers and the risk of T2DM as well as impaired glucose metabolism (IGM) and hyperglycemia in Chinese women of childbearing age. A total of 1145 women were divided into three groups (normal blood glucose metabolism group; IGM group; T2DM group). Biomarkers of iron metabolism (serum ferritin (SF), transferrin, soluble transferrin receptor (sTfR), transferrin saturation, serum iron, total body iron, and sTfR-to-lgferritin index) were measured. After adjusting for various confounding risk factors, SF and sTfR were positively associated with the risk of IGM (fourth vs. first quartile: SF odds ratio (OR) = 1.93 (95% CI 1.17-3.20) and sTfR OR = 3.08 (95% CI 1.84-5.14)) and T2DM (SF OR = 2.39 (95% CI 1.40-4.06) and sTfR OR = 3.84 (95% CI 2.53-5.83)). There was a nonlinear relationship between SF and risk of T2DM and hyperglycemia (p for nonlinearity < 0.01). Our findings suggested that SF and sTfR could be independent predictors of T2DM risk.

Investigation of Trends in the Research on Transferrin Receptor-Mediated Drug Delivery via a Bibliometric and Thematic Analysis

This study systematically reviews and characterizes the existing literature on transferrin/transferrin receptor-mediated drug delivery. Transferrin is an iron-binding protein. It can be used as a ligand to deliver various proteins, genes, ions, and drugs to the target site via transferrin receptors for therapeutic or diagnostic purposes via transferrin receptors. This study is based on a cross-sectional bibliometric analysis of 583 papers limited to the subject areas of pharmacology, toxicology, and pharmaceutics as extracted from the Scopus database in mid-September 2022. The data were analyzed, and we carried out a performance analysis and science mapping. There was a significant increase in research from 2018 onward. The countries that contributed the most were the USA and China, and most of the existing research was found to be from single-country publications. Research studies on transferrin/transferrin receptor-mediated drug delivery focus on drug delivery across the blood-brain barrier in the form of nanoparticles. The thematic analysis revealed four themes: transferrin/transferrin receptor-mediated drug delivery to the brain, cancer cells, gene therapy, nanoparticles, and liposomes as drug delivery systems. This study is relevant to academics, practitioners, and decision makers interested in targeted and site-specific drug delivery.

Association between soluble transferrin receptor and systolic hypertension in adults: National Health and Nutrition Examination Survey (2007–2010 and 2015–2018)

Background

Hypertension increases the global burden of disease and mortality. Iron metabolism is considered to be an important factor in hypertension. However, as an indicator of iron metabolism, little is known about the associations of soluble transferrin receptor (sTfR) with hypertension. We studied the relationship between sTfR and hypertension.

Materials and methods

We studied 7,416 adults aged 20 years old or above from the National Health and Nutrition Examination Survey (NHANES), a nationally representative, cross-sectional, population-based study. Weighted logistic regression was used to examine the association between markers of iron metabolism and hypertension. The restricted cubic spline (RCS) was used to characterize the association between sTfR and blood pressure.

Results

Weighted logistic regression showed that higher sTfR level was associated with higher odds of hypertension (OR = 1.05; 95% CI: 1.01–1.05; p = 0.001) after adjustment for all the potential confounding factors. Meanwhile, weighted logistic regression analyses indicated independent associations of high sTfR (p = 0.009) with systolic hypertension after adjusting for various different confounders. The result of restricted cubic splines showed a non-linear association between sTfR and systolic blood pressure among U.S. adults.

Conclusion

Soluble transferrin receptor was found to be an independent factor in systolic hypertension. And, a non-linear relationship between sTfR and systolic blood pressure was discovered.

Usefulness of Soluble Transferrin Receptor in the Diagnosis of Iron Deficiency Anemia in Rheumatoid Arthritis Patients in Clinical Practice

Aim. We analyzed the added value of sTfR measurement in routine clinical practice to standard parameters (SP) of iron deficiency in the detection of iron deficiency anemia (IDA) in patients with rheumatoid arthritis (RA). Methods. Blood samples from 116 patients with RA were analyzed in a prospective study. Based on biochemical parameters, patients were classified as having IDA, anemia of chronic disease (ACD), IDA with concomitant ACD (ACD/IDA), or “other anemia.” Sensitivity, specificity, positive (PPV), and negative predictive values (NPV) of sTfR and SP of iron status alone and in combination were calculated for the diagnosis of IDA in general, i.e., IDA or ACD/IDA. Results. In the whole sample, with regard to the diagnosis of iron deficiency (IDA or ACD/IDA), sTfR had a higher sensitivity compared both to the combined use of SP and to the combination of SP with sTfR (80.9% versus 66.7/54.8%). Specificity, PPV and NPV did not differ substantially. When patients were stratified in groups with high (CRP levels above the median, i.e., 24.1 mg/l) and low (CRP levels less or equal to the median) inflammation, the diagnostic superiority of sTfR was restricted to patients with high inflammation. In this group, the diagnostic performance of sTfR was superior both to the combined use of SP and the combination of SP with sTfR with higher sensitivity (100% versus 52.4%) and NPV (100% versus 77.7/76.7%) and comparable specificity and PPV. Conclusion. For the detection of iron depletion (IDA or ACD/IDA) in anemic RA patients, sTfR is superior to SP of iron deficiency only in highly inflammatory states.

High-Affinity Single-Domain Antibodies for Analyzing Human Apo- and Holo-Transferrin

A highly efficient technology for generating new monoclonal single-domain recombinant antibodies (nanobodies) was used to obtain a panel of nanobodies recognizing human apo- and/or holo-transferrin. This article is devoted to the primary analysis of the properties of two different variants of the new nanobodies obtained by us, as well as to the demonstration of the unique potential of their application for diagnostic studies. The simultaneous use of immunosorbents based on these nanobodies apparently makes it possible to detect changes in the relative abundance of apo- and holo-transferrin in human biological fluids. Such changes could potentially be indicative of an increased risk or degree of development of pathological processes, such as malignant neoplasms in humans.

Soluble transferrin receptor can predict all-cause mortality regardless of anaemia and iron storage status

Despite interest in the clinical implications of soluble transferrin receptor (sTfR), previous studies on the association of sTfR with mortality in the general population are lacking. Therefore, we analysed the association between sTfR and all-cause mortality in the general United States adult population. We conducted a prospective cohort study using National Health and Nutrition Examination Survey data from 2003 to 2010. A total of 5403 premenopausal nonpregnant females were analysed in this study. The mean age was 34.2 years (range 20.0–49.9 years). Participants were divided into log(sTfR) tertiles. The primary outcome was all-cause mortality. The secondary outcome was chronic kidney disease (CKD) development (composite of estimated glomerular filtration rate < 60 ml/min/1.73 m² and/or random urine albumin-to-creatinine ratio ≥ 30 mg/g). During a median 8.7 years of follow-up, 103 (1.9%) participants died. Compared with the reference group (log(sTfR) 0.45–0.57), the highest tertile of log(sTfR) was associated with all-cause mortality (log(sTfR) > 0.57, hazard ratio [HR] 1.77 [95% CI 1.05–2.98]) in a multivariable hazards model including covariates such as haemoglobin and ferritin. Patients in the highest tertile of log(sTfR) also had an increased risk of CKD relative to those in the reference tertile. High sTfR was associated with all-cause mortality and CKD regardless of anaemia and iron storage status.

Effects of Moderate Consumption of Red Wine on Hepcidin Levels in Patients with Type 2 Diabetes Mellitus

Iron overload is often associated with type 2 diabetes (T2D), indicating that hepcidin, the master regulator of iron homeostasis, might be involved in diabetes pathogenesis. Alcohol consumption may also result in increased body iron stores. However, the moderate consumption of wine with meals might be beneficial in T2D. This effect has been mainly attributed to both the ethanol and the polyphenolic compounds in wine. Therefore, we examined the effects of red wine on hepcidin in T2D patients and non-diabetic controls. The diabetic patients (n = 18) and age- and BMI-matched apparently healthy controls (n = 13) were men, aged 40−65 years, non-smoking, with BMI < 35 kg/m2. Following a 2-week alcohol-free period, both groups consumed 300 mL of red wine for 3 weeks. The blood samples for the iron status analysis were taken at the end of each period. The red wine intake resulted in a decrease in serum hepcidin in both the diabetic subjects (p = 0.045) and controls (p = 0.001). The levels of serum ferritin also decreased after wine in both groups, reaching statistical significance only in the control subjects (p = 0.017). No significant alterations in serum iron, transferrin saturation, or soluble transferrin receptors were found. The suppression of hepcidin, a crucial iron-regulatory hormone and acute-phase protein, in T2D patients and healthy controls, is a novel biological effect of red wine. This may deepen our understanding of the mechanisms of the cardiometabolic effects of wine in T2D.

Potential of cell tracking velocimetry as an economical and portable hematology analyzer

Anemia and iron deficiency continue to be the most prevalent nutritional disorders in the world, affecting billions of people in both developed and developing countries. The initial diagnosis of anemia is typically based on several markers, including red blood cell (RBC) count, hematocrit and total hemoglobin. Using modern hematology analyzers, erythrocyte parameters such as mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), etc. are also being used. However, most of these commercially available analyzers pose several disadvantages: they are expensive instruments that require significant bench space and are heavy enough to limit their use to a specific lab and lead to a delay in results, making them less practical as a point-of-care instrument that can be used for swift clinical evaluation. Thus, there is a need for a portable and economical hematology analyzer that can be used at the point of need. In this work, we evaluated the performance of a system referred to as the cell tracking velocimetry (CTV) to measure several hematological parameters from fresh human blood obtained from healthy donors and from sickle cell disease subjects. Our system, based on the paramagnetic behavior that deoxyhemoglobin or methemoglobin containing RBCs experience when suspended in water after applying a magnetic field, uses a combination of magnets and microfluidics and has the ability to track the movement of thousands of red cells in a short period of time. This allows us to measure not only traditional RBC indices but also novel parameters that are only available for analyzers that assess erythrocytes on a cell by cell basis. As such, we report, for the first time, the use of our CTV as a hematology analyzer that is able to measure MCV, MCH, mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RDW), the percentage of hypochromic cells (which is an indicator of insufficient marrow iron supply that reflects recent iron reduction), and the correlation coefficients between these metrics. Our initial results indicate that most of the parameters measured with CTV are within the normal range for healthy adults. Only the parameters related to the red cell volume (primarily MCV and RDW) were outside the normal range. We observed significant discrepancies between the MCV measured by our technology (and also by an automated cell counter) and the manual method that calculates MCV through the hematocrit obtained by packed cell volume, which are attributed to the artifacts of plasma trapping and cell shrinkage. While there may be limitations for measuring MCV, this device offers a novel point of care instrument to provide rapid RBC parameters such as iron stores that are otherwise not rapidly available to the clinician. Thus, our CTV is a promising technology with the potential to be employed as an accurate, economical, portable and fast hematology analyzer after applying instrument-specific reference ranges or correction factors.

Thrombocytopenia in COVID‑19 and vaccine‑induced thrombotic thrombocytopenia

The highly heterogeneous symptomatology and unpredictable progress of COVID-19 triggered unprecedented intensive biomedical research and a number of clinical research projects. Although the pathophysiology of the disease is being progressively clarified, its complexity remains vast. Moreover, some extremely infrequent cases of thrombotic thrombocytopenia following vaccination against SARS-CoV-2 infection have been observed. The present study aimed to map the signaling pathways of thrombocytopenia implicated in COVID-19, as well as in vaccine-induced thrombotic thrombocytopenia (VITT). The biomedical literature database, MEDLINE/PubMed, was thoroughly searched using artificial intelligence techniques for the semantic relations among the top 50 similar words (>0.9) implicated in COVID-19-mediated human infection or VITT. Additionally, STRING, a database of primary and predicted associations among genes and proteins (collected from diverse resources, such as documented pathway knowledge, high-throughput experimental studies, cross-species extrapolated information, automated text mining results, computationally predicted interactions, etc.), was employed, with the confidence threshold set at 0.7. In addition, two interactomes were constructed: i) A network including 119 and 56 nodes relevant to COVID-19 and thrombocytopenia, respectively; and ii) a second network containing 60 nodes relevant to VITT. Although thrombocytopenia is a dominant morbidity in both entities, three nodes were observed that corresponded to genes (AURKA, CD46 and CD19) expressed only in VITT, whilst ADAM10, CDC20, SHC1 and STXBP2 are silenced in VITT, but are commonly expressed in both COVID-19 and thrombocytopenia. The calculated average node degree was immense (11.9 in COVID-19 and 6.43 in VITT), illustrating the complexity of COVID-19 and VITT pathologies and confirming the importance of cytokines, as well as of pathways activated following hypoxic events. In addition, PYCARD, NLP3 and P2RX7 are key potential therapeutic targets for all three morbid entities, meriting further research. This interactome was based on wild-type genes, revealing the predisposition of the body to hypoxia-induced thrombosis, leading to the acute COVID-19 phenotype, the 'long-COVID syndrome', and/or VITT. Thus, common nodes appear to be key players in illness prevention, progression and treatment.

Galactose specific lectins from prostate tissue with different pathologies: biochemical and cellular studies

BACKGROUND

Galectins-galactose-specific lectins are involved in various types of cell activities, including apoptosis, cell cycle regulation, inflammation and cell transformation. Galectins are implicated in prostate malignat transformation. It is not known yet if prostate glands with different grade of pathologies are expressing different galectins and if these galectins express different effects on the cell viability.

METHODS

Cytosolic galactose-spesific lectin fractions from prostate tissue with different diagnosis were purified by affinity chromatography and analyzed by electrophoresis in polyacrylamide gel electrophoresis with sodium dodecyl sulphate. The lectin effects in a source-dependent maner were studied on cell viability on peripheral lymphocytes by MTT reduction method and on apoptosis by flow cytometry method.

RESULTS

Affinity purified galactose-specific lectins fractions from normal and pathological tissue samples are characterized with different protein composition and they express different effects on cell viability and apoptosis.

CONCLUSION

The effects of cytosolic galactose-specific lectins depend on the source of lectin fraction (glandular tissue disease). We suppose that the released cytosolic galectins from prostatic high grade intraepithelial neoplasia and adenocarcinoma tissue could suppress the immune status of the host patients.

Prevalence and associated factors of iron deficiency in Spanish children aged 1 to 11 years

Iron deficiency (ID) is the most common nutritional deficiency affecting children worldwide. Most traditional laboratory parameters to assess ID can be altered by infections or other inflammatory states, including obesity. The aims of this study were to determine the prevalence of ID in healthy children and to analyse associated factors, avoiding potential confounding factors through the use of serum transferrin receptor (sTfR), reticulocyte haemoglobin content and sTfR/log ferritin index. A cross-sectional population-based study was conducted on 951 children aged 1 to 11 years in Almería (Spain). ID was detected in 7.7% of children and iron deficiency anaemia in 0.9%. Multivariate analysis identified the following as independent risk factors: age under 5 years (OR: 2.2, 95% CI: 1.35-3.6); excessive consumption of cow's milk and dairy products (OR: 1.87, 95% CI: 1.13-3.1); and insufficient consumption of vegetables (OR: 2.7, 95% CI: 1.2-6.1).Conclusions: Using a combination of iron status parameters with greater discriminatory power than classical measures, this study detected a considerable iron deficiency prevalence in Spanish children. Younger children and specific dietary habits exhibit a particular risk for ID, so special attention should be paid to this population. What is Known: • Iron deficiency remains the most prevalent nutritional deficit worldwide, and children aged under 3 years are the most vulnerable to this condition. • Accurate assessment of iron status, based on a combination of biochemical indicators, can often be complicated. What is New: • Iron deficiency continues to present a health problem in Spanish children aged 1 to 11 years, considering the serum transferrin receptor and reticulocyte haemoglobin content for diagnosis. • Excessive consumption of dairy products and low consumption of vegetables are independent risk factors for iron deficiency.

Alteration of Iron Concentration in Alzheimer's Disease as a Possible Diagnostic Biomarker Unveiling Ferroptosis

Proper functioning of all organs, including the brain, requires iron. It is present in different forms in biological fluids, and alterations in its distribution can induce oxidative stress and neurodegeneration. However, the clinical parameters normally used for monitoring iron concentration in biological fluids (i.e., serum and cerebrospinal fluid) can hardly detect the quantity of circulating iron, while indirect measurements, e.g., magnetic resonance imaging, require further validation. This review summarizes the mechanisms involved in brain iron metabolism, homeostasis, and iron imbalance caused by alterations detectable by standard and non-standard indicators of iron status. These indicators for iron transport, storage, and metabolism can help to understand which biomarkers can better detect iron imbalances responsible for neurodegenerative diseases.

Influence of chronic training workload on the hematological profile: a pilot study in sedentary people, amateur and professional cyclists

Background and aim:

The assessment of hematological profile requires to identify possible sources of biological variability, including exercise-related variations. This study was hence aimed to evaluate hematological profile variations in amateur and professional athletes, and establish their possible dependence on cumulative training volume.

Materials and Methods:

The study population consisted of 59 sedentary male subjects, 78 amateur and 80 professional male cyclists, in whom a large number of hematological variables were measured at rest.

Results:

Red blood cell (RBC) count and hemoglobin were decreased in the two athlete cohorts compared to sedentary subjects, but did not differ between amateur and professional cyclists. Hematocrit was gradually and significantly decreased in parallel with cumulative training volume. Amateur cyclists displayed higher mean corpuscular volume (MCV) and lower mean corpuscular hemoglobin concentration (MCHC) values than sedentary subjects and professional cyclists, whilst mean corpuscular hemoglobin (MCH) was higher in professional cyclists. The reticulocyte count and soluble transferrin receptor (sTFR) values were similar across all groups. Serum ferritin was higher in professional cyclists than in the other two groups, whilst transferrin gradually decreased from sedentary group to the two cohorts of amateur and professional cyclists. In univariate analysis, cumulative training volume was inversely associated with age, body mass index (BMI), RBC count, hematocrit, hemoglobin and transferrin, whilst a positive association was found with ferritin. In multivariate analysis, BMI, RBC count and ferritin remained significantly associated with training volume.

Conclusions:

These results show that the volume of endurance training may affect some hematological variables. (www.actabiomedica.it)

Linkage of alterations in systemic iron homeostasis to patients' outcome in sepsis: a prospective study

Background

Sepsis, a dysregulated host response following infection, is associated with massive immune activation and high mortality rates. There is still a need to define further risk factors and laboratory parameters predicting the clinical course. Iron metabolism is regulated by both, the body’s iron status and the immune response. Iron itself is required for erythropoiesis but also for many cellular and metabolic functions. Moreover, iron availability is a critical determinant in infections because it is an essential nutrient for most microbes but also impacts on immune function and intravascular oxidative stress. Herein, we used a prospective study design to investigate the putative impact of serum iron parameters on the outcome of sepsis.

Methods

Serum markers of iron metabolism were measured in a prospective cohort of 61 patients (37 males, 24 females) with sepsis defined by Sepsis-3 criteria in a medical intensive care unit (ICU) and compared between survivors and non-survivors. Regulation of iron parameters in patients stratified by focus of infection and co-medication as well as association of the markers with sepsis severity scores and survival were investigated with linear and logistic regression corrected for sex and age effects.

Results

Positive correlations of increased serum iron and ferritin concentrations upon ICU admission with the severity of organ failure (SOFA score) and with mortality were observed. Moreover, high TF-Sat, elevated ferritin and serum iron levels and low transferrin concentrations were associated with reduced survival. A logistic regression model consisting of SOFA and transferrin saturation (SOFA–TF-Sat) had the best predictive power for survival in septic ICU patients. Of note, administration of blood transfusions prior to ICU admission resulted in increased TF-Sat and reduced survival of septic patients.

Conclusions

Our study could show an important impact of serum iron parameters on the outcome of sepsis. Furthermore, we identified transferrin saturation as a stand-alone predictor of sepsis survival and as a parameter of iron metabolism which may in a combined model improve the prediction power of the SOFA score.

Trial registration

The study was carried out in accordance with the recommendations of the Declaration of Helsinki on biomedical research. The study was approved by the institutional ethics review board of the Medical University Innsbruck (study AN2013-0006).

Erythrocyte-rich thrombi related to serum iron contribute to single stent retrieval and favorable clinical outcomes in acute ischemic stroke by endovascular treatment

BACKGROUND

Erythrocyte-rich thrombi seem to be associated with favorable clinical outcomes of patients with AIS by endovascular treatment (EVT), as observed from previous studies. However, only few studies show whether erythrocyte-rich thrombi can be associated with favorable clinical outcomes by EVT and which factor can be related to erythrocyte-rich thrombi. This retrospective study aimed to evaluate the relationship between erythrocyte-rich thrombi and favorable clinical outcomes and further explored factors associated with erythrocyte-rich thrombi.

METHODS

This study was carried out retrospectively from March 2016 to April 2019 on patients who suffered acute ischemic stroke and were treated by EVT at this stroke center. The laboratory test and clinical data were assessed for the relationship between erythrocyte-rich thrombi and favorable clinical outcomes and factors associated with erythrocyte-rich thrombi. All thrombi were divided into erythrocyte-rich thrombi group and fibrin-rich thrombi group based on the proportion of area of the predominant composition which was more than 50% in retrieved thrombi.

RESULTS

This retrospective study enrolled 84 patients, including 32 patients in the erythrocyte-rich thrombi group and 52 patients in the fibrin-rich thrombi group. It showed single stent retrieval (p = 0.017, adjusted OR: 4.061, 95% CI: 1.281-12.872) and favorable clinical outcomes (p < 0.001, adjusted OR: 14.648, 95% CI: 4.637-46.270) were both significantly associated with erythrocyte-rich thrombi. A significant difference in the factor associated with erythrocyte-rich thrombi was serum iron, which correlated positively with erythrocyte fraction in thrombi (p < 0.001, r: 0.452).

CONCLUSIONS

Erythrocyte-rich thrombi could contribute to single stent retrieval and favorable clinical outcomes by EVT, and serum iron might be the factor associated with erythrocyte-rich thrombi.

Classic and emergent indicators for the assessment of human iron status

Iron deficiency is the leading cause of anemia, a significant global public health problem. Different methods exist for assessing iron nutritional status, including laboratory tests that focus on storage, transportation, and iron functional compartment parameters. Classical markers such as bone marrow, serum iron, ferritin, hemoglobin, erythrocyte parameters, transferrin, transferrin receptors, and zinc protoporphyrin are discussed in this review. Additional parameters calculated from these indicators, including transferrin saturation, ferritin index and Thomas plot, and some emergent parameters such as hepcidin, erythroferrone, and low hemoglobin density are also discussed. There is no a single indicator for assessing iron nutritional status. Therefore, the use of more than one indicator may be the best practice to obtain the correct diagnosis, also considering the influence of inflammation/infection on many of these indicators. The constant validation of the current parameters, the improvement of assessment methods, and the identification of new indicators will be the key to refine the assessment of iron nutritional status and the right choice of treatment for its improvement.

Characteristics of iron status, oxidation response, and DNA methylation profile in response to occupational iron oxide nanoparticles exposure

Although the growing development and application of iron oxide nanoparticles (IONPs) may pose exposure risk and adverse health outcomes, biological changes due to occupational exposure remain unexplored. This cross-sectional study recruited 23 workers at a plant that manufactures IONPs and 23 age- and sex-matched controls without metal-rich occupational hazards exposure. Exposure metrics at worksites were monitored, and iron status, oxidation markers, and methylation profiles of genomic DNA in peripheral blood were measured using corresponding enzyme-linked immunosorbent assays and methylation-specific polymerase chain reaction (PCR), respectively. The mass concentration, number counting, and surface area concentration of airborne particles at the worksite significantly increased during the work process of manufacturing/handling IONPs. Overall, compared to controls, workers exhibited increased 5-hydroxymethylcytosine (5hmC) levels without changes in 5-methylcytosine (5mC), hepcidin methylation, iron, soluble transferrin receptor (sTfR), ferritin, hepcidin, 8-hydroxydeoxyguanosine, and glutathione. A positive correlation was found between 5hmC and IONP exposure year with adjustment for age, sex, and cotinine using partial correlation analyses ( r = 0.521, p < 0.001). After stratification of INOPs exposure and 5hmC levels, the univariate general linear model with adjustment for age, sex, and cotinine found that the estimated mean levels of 5mC and sTfR in subjects with low and high 5hmC levels among controls were 11% and 14.4% ( p ≤ 0.01) and 80.9 nM and 70.3 nM ( p < 0.05), respectively. The estimated mean levels of sTfR in workers and controls with low 5hmC levels were 88.3 nM and 68.7 nM ( p ≤ 0.01). Multivariate linear regression analyses suggested an association between sTfR and 5hmC (standardized β = −0.420, p = 0.014) and female sex (standardized β = 0.672, p < 0.001) for subjects with low 5hmC levels. These findings suggest that increased 5hmC could be differentially employed to monitor an epigenetic signature with steady iron homeostasis for occupational IONP-exposed individuals who are likely to experience early but specific decreased sTfR, especially for females concurrent with the onset of increment in 5hmC at low level.

The Central Role of Iron in Human Nutrition: From Folk to Contemporary Medicine

Iron is a fundamental element in human history, from the dawn of civilization to contemporary days. The ancients used the metal to shape tools, to forge weapons, and even as a dietary supplement. This last indication has been handed down until today, when martial therapy is considered fundamental to correct deficiency states of anemia. The improvement of the martial status is mainly targeted with dietary supplements that often couple diverse co-factors, but other methods are available, such as parenteral preparations, dietary interventions, or real-world approaches. The oral absorption of this metal occurs in the duodenum and is highly dependent upon its oxidation state, with many absorption influencers possibly interfering with the intestinal uptake. Bone marrow and spleen represent the initial and ultimate step of iron metabolism, respectively, and the most part of body iron circulates bound to specific proteins and mainly serves to synthesize hemoglobin for new red blood cells. Whatever the martial status is, today’s knowledge about iron biochemistry allows us to embrace exceedingly personalized interventions, which however owe their success to the mythical and historical events that always accompanied this metal.

The plasma proteome and the acute phase protein response in canine pyometra

Canine pyometra is a common inflammatory disease of uterus in sexually mature bitches caused by secondary bacterial infection, leading to change in plasma proteins associated with the innate immune system. Proteomic investigation is increasingly being applied to canine diseases in order to identify and quantify significant changes in the plasma proteome. The aim of the study was to assess and quantify changes in plasma proteome profiles of healthy dogs and pyometra affected bitches using a TMT-based high-resolution quantitative proteomic approach. As a result, 22 proteins were significantly down-regulated including transthyretin, antithrombin, retinol-binding protein, vitamin D binding protein, paraoxonase 1, and kallikrein, while 16 were significantly up-regulated including haptoglobin light chain, alpha-1-acid glycoprotein, C-reactive protein precursor, and lipopolysaccharide-binding protein in dogs with pyometra. Pathway analysis indicated that acute inflammatory response, regulation of body fluid levels, protein activation cascade, the humoral immune response, and phagocytosis were affected in pyometra. Validation of biological relevance of the proteomic study was evident with significant increases in the concentrations of haptoglobin, C-reactive protein, alpha-1-acid glycoprotein, and ceruloplasmin by immunoassay. Pyometra in bitches was shown to stimulate an increase in host defence system proteins in response to inflammatory disease including the acute phase proteins. SIGNIFICANCE: The label-based high-resolution quantitative proteomics analysis and bioinformatic approach used in this study provide insight into the complex pathophysiology of inflammation associated with pyometra revealing proteins with biomarker potential. Early diagnosis and therapeutic intervention may prevent severe complications associated with advancing sepsis in dogs with pyometra. Therefore the identification of diagnostic biomarkers that, after clinical validation may be used in veterinary practice and protein relevant to pathways responding to disease are important findings of the study. Data are available via ProteomeXchange with identifier PXD015951.

[Characterization of anemic syndrome in cancer patients with sepsis in the early postoperative period.]

A study of the main indicators of red blood (RBC, HGB, HCT, MCV, MCH) and the concentration of EPO, sTfR in 9 cancer patients with anemic syndrome (AS) against sepsis was carried out. Among them, patients with chronic disease anemia (ACh), with normocytic, normochromic characteristics of red blood cells and low hematocrit predominated. In 2 patients, microcytosis and erythrocyte hypochromia were noted, the concentration of sTfR was significantly higher than normal (0.9 ± 0.07 μg / ml), amounted to 2.7 μg / ml in one of them and 1.9 μg / ml in the other, which testified to t iron deficiency erythropoiesis (IDE) on the background of the ACh,. In 7 patients with ACh without IDE, sTfR values were within the normal range (0.1-1.2) μg / ml, the median was 0.5 μg/ml. In all patients with sepsis, the production of EPO was inadequate for the severity of the AS, to a lesser extent in patients with IDE. The average EPO production in the group was 19.4 ± 5.1 (7.7-52.8) mU / ml, median = 12.1 mE / ml. Further studies of EPO, sTfR are planned in order to determine their role in therapeutic tactics in the correction of AS in cancer patients with sepsis.

Diagnostic performance of reticulocyte hemoglobin equivalent in assessing the iron status

Background

Measurement of reticulocyte hemoglobin equivalent (RET‐He) is rapid, convenient, and cost‐effective. Yet, researches on its performance in diagnosing iron deficiency with concurrent inflammation are limited. Hence, this study investigated RET‐He value in various states, including inflammation, and evaluated its diagnostic performance in iron status assessment.

Methods

Retrospectively, 953 clinical data and laboratory results—complete blood count, reticulocyte count, RET‐He, and serum ferritin—were reviewed. Patients on iron therapy were excluded. Iron status was defined by serum ferritin as the reference method. RET‐He among populations was investigated. Its diagnostic performance and optimal cutoff were determined by ROC analysis.

Results

Three population groups were classified: healthy control, iron deficiency anemia (IDA), and non‐ID anemia. Significantly, RET‐He value in IDA was lower than that of healthy control, anemia of inflammation, and chronic kidney disease (P < .0001). Low RET‐He was also observed in IDA with concomitant inflammation despite normal‐to‐high serum ferritin levels. No significant difference was observed between RET‐He values in pure IDA and thalassemia (P = .57). ROC curve analysis revealed AUC of 0.876 (P < .0001) at cutoff 30 pg, by which IDA was discriminated with 74.2% sensitivity and 97.4% specificity. Applying cutoff ≤30 pg, IDA can be diagnosed with 96% sensitivity, 97.4% specificity, 80% PPV, and 99.6% NPV. Hence, RET‐He >30 pg signifies a non‐IDA state.

Conclusion

In addition to convenience and cost‐effectiveness, RET‐He cutoff >30 pg can be potentially used to exclude IDA due to its excellent diagnostic sensitivity and specificity.

New diagnostic tools for delineating iron status

Recent advances in our understanding of iron metabolism regulation and crosstalk with erythropoiesis have provided insight into the pathophysiology of multiple disease conditions. For instance, the peptide hormone hepcidin is central to the regulation of iron metabolism. Its effect on cellular iron concentration involves binding ferroportin, the main iron export protein, resulting in its internalization and degradation and leading to iron sequestration within ferroportin-expressing cells. Furthermore, hepcidin regulation by erythropoiesis is attributed in large part to a bone marrow-derived hormone erythroferrone. Erythroferrone-induced hepcidin suppression in diseases of expanded hematopoiesis results in iron overload. Conversely, diseases, such as iron refractory iron deficiency anemia and anemia of chronic inflammation, are characterized by aberrantly increased hepcidin, resulting in iron sequestration and decreased circulating iron and eventually leading to iron-restricted erythropoiesis. Lastly, because iron functions in concert with erythropoietin to promote erythroid precursor survival, proliferation, and differentiation, iron deficiency anemia is a consequence not only of decreased hemoglobin synthesis in each cell but also, a decrease in erythropoietin responsiveness in the bone marrow. How to translate this new information to the clinical setting has not been fully elucidated. The purpose of this manuscript is to summarize current standard tools for identifying iron deficiency in anemic patients; explore the tools and context for evaluating novel markers, such as hepcidin, erythroferrone, and markers of the iron restriction response; and assess available evidence for how their use could increase our understanding of health outcomes in clinically challenging cases.

Hepcidin and diabetes are independently related with soluble transferrin receptor levels in chronic dialysis patients

Background: Soluble transferrin receptor (sTfR) is a biomarker of erythropoiesis, which is often impaired in dialysis patients. The aim of our study was to evaluate sTfR levels in chronically dialyzed patients and assess potential determinants of its levels. Methods: We performed a cross-sectional study by evaluating 246 end-stage renal disease patients undergoing dialysis and 32 healthy controls. Circulating levels of interleukin (IL)-6, C-reactive protein (CRP), tumor necrosis factor (TNF)-α, hepcidin, sTfR, growth differentiation factor 15 (GDF15), and traditional iron metabolism markers were measured, as well as hemogram parameters. Clinical data was obtained from all patients. Results: Compared to controls, patients presented similar values of sTfR, reticulocytes and reticulocyte production index (RPI), and significantly higher levels of IL-6, CRP, ferritin, hepcidin, TNF-α, and GDF15. Iron, transferrin, hemoglobin levels, erythrocyte count, mean cell hemoglobin (MCH), and mean cell hemoglobin concentration (MCHC) values were significantly lower in dialysis group. Within patients, sTfR values were higher in diabetic patients and were positively and significantly correlated with reticulocytes and erythrocytes, RPI, and therapeutic doses of erythropoiesis stimulating agents (ESA) and intravenous iron; and inversely and significantly correlated with circulating iron, ferritin, transferrin saturation, hepcidin, MCH, and MCHC. In multiple linear regression analysis, ESA dose, RPI, serum iron, diabetes, and hepcidin levels were independently associated with sTfR levels in dialysis patients and, thus, with erythropoiesis. Conclusion: Our data suggest that, besides RPI and ESA dose, diabetes and hepcidin are closely related to erythropoiesis in dialysis patients. The influence of diabetes on sTfR levels deserves further investigation.

New Biomarkers of Ferric Management in Multiple Myeloma and Kidney Disease-Associated Anemia

Multiple myeloma (MM) is a malignancy of clonal plasma cells accounting for approximately 10% of haematological malignancies. MM mainly affects older patients, more often males and is more frequently seen in African Americans. The most frequent manifestations of MM are anaemia, osteolytic bone lesions, kidney failure and hypercalcemia. The anaemia develops secondary to suppression of erythropoiesis by cytokine networks, similarly to the mechanism of anaemia of chronic disease. The concomitant presence of kidney failure, especially chronic kidney disease (CKD) and MM per se, leading to anaemia of chronic disease (ACD) in combination, provoked us to pose the question about their reciprocal dependence and relationship with specific biomarkers; namely, soluble transferrin receptor (sTfR), growth differentiation factor 15 (GDF15), hepcidin 25 and zonulin. One or more of these are new biomarkers of ferric management may be utilized in the near future as prognostic predictors for patients with MM and kidney failure.

Effect of diet with carbohydrate but without daily energy restriction on serum glucose, lactate, and selected mineral and lipid levels in streptozotocin-induced experimental diabetic rats

Objective: Type I diabetes is a disease characterised by an extreme reduction in serum insulin levels. Diet and exercise have gained considerable attention in the treatment of diabetes. Therefore, this study was carried out to investigate the effect of diet with carbohydrate but without daily energy restriction on various metabolites (glucose, triglycerides, cholesterol, lactate), some electrolytes (Ca, Mg, Na, K, P, Cl) and essential metals (Mn, Co, Cu, Se, Zn, Fe) in the blood of rats with streptozotocin-induced diabetes. Materials and methods: Thirty-three male rats were divided into four groups of standard rat diet (SR)-fed control, SR-diet fed diabetics, low carbohydrate-standard protein-high fat (LCSPHF) diet-fed diabetics, and very low carbohydrate-high protein-high fat (VLCHPHF) diet-fed diabetics. Diabetes was induced by an i.p. injection of 50 mg/kg streptozotocin. The rats were fed with the specially prepared diets for 28 days. Results: The decreased-serum Cl and the increased-serum glucose levels were only the difference between the controls and SR diet-fed diabetic rats regarding to measured parameters. Lowering carbohydrate and increasing fat ratio in diet caused an increase in serum cholesterol and triglyceride levels leading to an increased-serum Fe and Ca, and decreased-serum Na and Cu levels in diabetic rats. Conclusion: The serum mineral changes should be taken into consideration together with the changes in serum glucose, cholesterol, and triglyceride levels for the secondary complications of diabetes mellitus.

Soluble transferrin receptor and soluble transferrin receptor/log ferritin index in diagnosis of iron deficiency anemia in pediatric inflammatory bowel disease

BACKGROUND

There is no single reliable marker of iron homeostasis in inflammatory bowel disease.

AIMS

To determine diagnostic usefulness of soluble transferrin receptor and soluble transferrin receptor/log ferritin index in iron deficiency anemia in children with inflammatory bowel disease.

METHODS

We assessed soluble transferrin receptor in serum and calculated soluble transferrin receptor/log ferritin index in 75 children with inflammatory bowel disease. Diagnostic ability to identify iron deficiency anemia was examined by receiver operating characteristic analysis.

RESULTS

Study group comprised 27 cases of iron deficiency anemia, 6 anemia of chronic disease with iron deficiency, 5 anemia of chronic disease. Soluble transferrin receptor was significantly increased in children with iron deficiency anemia (median: 1.63 μg/ml) compared to non-anemic children (median: 1.02 μg/ml). Soluble transferrin receptor/log ferritin index was significantly higher in iron deficiency anemia (median: 1.76) than in anemia of chronic disease (median: 0.55), anemia of chronic disease with iron deficiency (median: 0.68) or patients without anemia (median: 0.72). Soluble transferrin receptor and its index were not correlated with disease activity or inflammatory markers. Diagnostic power for soluble transferrin receptor/log ferritin index (0.864) was superior to soluble transferrin receptor (0.768) in iron deficiency anemia recognition.

CONCLUSION

Soluble transferrin receptor/log ferritin index has better diagnostic utility than soluble transferrin receptor for iron deficiency anemia detection in pediatric inflammatory bowel disease.

Role of Soluble Transferrin Receptor and Transferrin Receptor-Ferritin Index to Detect Iron Deficiency Anemia in Regular Hemodialysis Patients

BACKGROUND:

Several iron indicators can be used to detect iron deficiency anaemia (IDA) where confounding comorbidities occurred such as patients with regular hemodialysis.

AIM:

This study was aimed to determine the diagnostic value of serum transferrin receptor (sTfR) and transferrin receptor-transferrin index (TfR-F index) and to combine these two markers in detecting IDA in regular hemodialysis anaemic patients.

METHODS:

There were 70 patients recruited consecutively. IDA was diagnosed based on TS < 20% and ferritin level < 200 ng/L and functional iron deficiency when TS < 20% and ferritin > 200 ng/L. TfR-F index calculated as sTfR/log ferritin.

RESULTS:

Correlation of ferritin to iron level was changed when its correlation adjusted by confounding inflammation (CRP level > 10). The correlation strength of ferritin to iron serum before adjusted was r = 0.37 with p = 0.02 but became r = 0.65 with p = 0.023 after adjusted to CRP > 10. In inflammation (CRP > 10), ferritin mild-moderately correlated with iron but became moderately strong when there was no inflammation (CRP < 10). AUC for sTfR was 0.77 with p = 0.028 (95% CI 0.55-0.99), and for TfR-F index has larger AUC 0.85% with p = 0.004 (95%CI 0.69-1.00), hence TfR-F index more superior than sTfR. sTfR and sTfR-F index were not correlated with CRP with p > 0.05, and sTfR and TfR-F index mean level was different between IDA and ACD patients although not statistically significant.

CONCLUSION:

When sTfR and the TfR-F index used in combination to detect IDA, we found the largest AUC on ROC 0.98 (95% CI 0.94-1.00).

The usefulness of reticulocyte haemoglobin content, serum transferrin receptor and the sTfR-ferritin index to identify iron deficiency in healthy children aged 1-16 years

This cross-sectional study, conducted on a population-based representative sample, evaluates the usefulness of reticulocyte haemoglobin content (CHr), serum transferrin receptor (sTfR) and sTfR/log ferritin (sTfR-F index) to recognise iron deficiency (ID) without anaemia, provides specific cut-off points for age and gender, and proposes a new definition of ID. A total of 1239 healthy children and adolescents aged 1-16 years were included. Complete blood count, iron biomarkers, erythropoietin, C-reactive protein, CHr, sTfR, and sTfR-F index were determined. ROC curves were obtained and sensitivity, specificity, predictive values, likelihood ratios, and accuracy for each specific cut-off points were calculated. Seventy-three had ID without anaemia. Area under the curve for sTfR-F index, sTfR and CHr were 0.97 (CI95% 0.95-0.99), 0.87 (CI95% 0.82-0.92) and 0.68 (CI95% 0.61-0.74), respectively. The following cut-off points defined ID: sTfR-F Index > 1.5 (1-5 years and 12-16 years boys) and > 1.4 (6-11 years and 12-16 years girls); sTfR (mg/L) > 1.9 (1-5 years), > 1.8 (6-11 years), > 1.75 (12-16 years girls) and > 1.95 (12-16 years boys); and CHr (pg) < 27 (1-5 years) and < 28.5 (6-16 years).Conclusions: CHr, sTfR and the sTfR-F index are useful parameters to discriminate ID without anaemia in children and adolescents, and specific cut-off values have been established. The combination of these new markers offers an alternative definition of ID with suitable discriminatory power. What is Known: • In adults, reticulocyte haemoglobin content (CHr), serum transferrin receptor (sTfR) and sTfR/log ferritin index (sTfR-F index) have been evaluated and recognised as reliable indicators of iron deficiency (ID). • Clinical manifestations of ID may be present in stages prior to anaemia, and the diagnosis of ID without anaemia continues to pose problems. What is New: • CHr, sTfR and the sTfR-F index are useful parameters in diagnosis of ID in childhood and adolescence when anaemia is not present. • We propose a new strategy for the diagnosis of ID in childhood and adolescence, based on the combination of these measures, which offer greater discriminatory power than the classical parameters.

Established and Emerging Concepts to Treat Imbalances of Iron Homeostasis in Inflammatory Diseases

Inflammation, being a hallmark of many chronic diseases, including cancer, inflammatory bowel disease, rheumatoid arthritis, and chronic kidney disease, negatively affects iron homeostasis, leading to iron retention in macrophages of the mononuclear phagocyte system. Functional iron deficiency is the consequence, leading to anemia of inflammation (AI). Iron deficiency, regardless of anemia, has a detrimental impact on quality of life so that treatment is warranted. Therapeutic strategies include (1) resolution of the underlying disease, (2) iron supplementation, and (3) iron redistribution strategies. Deeper insights into the pathophysiology of AI has led to the development of new therapeutics targeting inflammatory cytokines and the introduction of new iron formulations. Moreover, the discovery that the hormone, hepcidin, plays a key regulatory role in AI has stimulated the development of several therapeutic approaches targeting the function of this peptide. Hence, inflammation-driven hepcidin elevation causes iron retention in cells and tissues. Besides pathophysiological concepts and diagnostic approaches for AI, this review discusses current guidelines for iron replacement therapies with special emphasis on benefits, limitations, and unresolved questions concerning oral versus parenteral iron supplementation in chronic inflammatory diseases. Furthermore, the review explores how therapies aiming at curing the disease underlying AI can also affect anemia and discusses emerging hepcidin antagonizing drugs, which are currently under preclinical or clinical investigation.

Exosomes derived from rAAV/AFP-transfected dendritic cells elicit specific T cell-mediated immune responses against hepatocellular carcinoma

Background

Dendritic cell (DC)-derived exosomes (Dexs) have been proved to induce and enhance antigen-specific T cell responses in vivo, and previous clinical trials have shown the feasibility and safety of Dexs in multiple human cancers. However, there is little knowledge on the efficacy of Dexs against hepatocellular carcinoma (HCC) until now.

Methods

In this study, human peripheral blood-derived DCs were loaded with recombinant adeno-associated viral vector (rAAV)-carrying alpha-fetoprotein (AFP) gene (rAAV/AFP), and high-purity Dexs were generated. Then naive T cells were stimulated with Dexs to investigate the specific T cell-mediated immune responses against HCC.

Results

Our findings showed that Dexs were effective to stimulate naive T cell proliferation and induce T cell activation to become antigen-specific cytotoxic T lymphocytes (CTLs), thereby exhibiting antitumor immune responses against HCC. In addition, Dex-sensitized DC precursors seemed more effective to trigger major histocompatibility complex class I (MHC I)-restricted CTL response and allow DCs to make full use of the minor antigen peptides, thereby maximally activating specific immune responses against HCC.

Conclusion

It is concluded that Dexs, which combine the advantages of DCs and cell-free vectors, are promising to completely, or at least in part, replace mature DCs (mDCs) to function as cancer vaccines or natural antitumor adjuvant.

Carnosine supplementation reduces plasma soluble transferrin receptor in healthy overweight or obese individuals: a pilot randomised trial

Abnormalities of iron homeostasis have been linked to insulin resistance, type 2 diabetes and cardiovascular disease. Carnosine, an over-the-counter food supplement with chelating properties, has been shown to decrease serum iron and improve glucose metabolism in diabetic rodents. We have previously demonstrated that carnosine supplementation prevented worsening of glucose metabolism in healthy overweight and obese middle-aged adults. Yet, the impact of carnosine on markers of iron metabolism in humans has not been investigated. We aimed to determine whether carnosine supplementation has an effect on iron parameters in overweight and obese, otherwise healthy adults. We included 26 participants, who were randomly allocated to receive 1 g carnosine (n = 14) or identical placebo (n = 12) twice daily for 12 weeks. Iron parameters including iron, ferritin, transferrin, soluble transferrin receptor, total iron binding capacity and iron saturation were measured in serum or plasma by standard commercial assays. Carnosine supplementation decreased plasma soluble transferrin receptor compared to placebo (mean change difference ± standard error: - 0.07 ± 0.03 mg/l, p = 0.04). None of the other iron parameters were different between carnosine and placebo groups. At follow-up, soluble transferrin receptor was associated inversely with urinary carnosine concentrations and positively with serum carnosinase-1 activity (both p < 0.02). Our findings suggest that carnosine may modulate iron metabolism in high-risk groups which could ameliorate insulin resistance and prevent type 2 diabetes. Larger human clinical trials are required to confirm our results.

Intrinsic Iron Release Is Associated with Lower Mortality in Patients with Stable Coronary Artery Disease-First Report on the Prospective Relevance of Intrinsic Iron Release

Intrinsic iron release is discussed to have favorable effects in coronary artery disease (CAD). The aim of this study was to evaluate the prognostic relevance of intrinsic iron release in patients with CAD. Intrinsic iron release was based on a definition including hepcidin and soluble transferrin receptor (sTfR). In a cohort of 811 patients with angiographically documented CAD levels of hepcidin and sTfR were measured at baseline. Systemic body iron release was defined as low levels of hepcidin (<24 ng/mL) and high levels of sTfR (≥2 mg/L). A commercially available ELISA (DRG) was used for measurements of serum hepcidin. Serum sTfR was determined by using an automated immunoassay (). Cardiovascular mortality was the main outcome measure. The criteria of intrinsic iron release were fulfilled in 32.6% of all patients. Significantly lower cardiovascular mortality rates were observed in CAD patients with systemic iron release. After adjustment for body mass index, smoking status, hypertension, diabetes, dyslipidemia, sex, and age, the hazard ratio for future cardiovascular death was 0.41. After an additional adjustment for surrogates of the size of myocardial necrosis (troponin I), anemia (hemoglobin), and cardiac function and heart failure severity (N-terminal pro B-type natriuretic peptide), this association did not change (Hazard ratio 0.37 (95% confidence interval 0.14⁻0.99), p = 0.047). In conclusion, significantly lower cardiovascular mortality rates were observed in CAD patients with intrinsic iron release shown during follow-up.

Biomarkers of Nutrition for Development (BOND)-Iron Review

This is the fifth in the series of reviews developed as part of the Biomarkers of Nutrition for Development (BOND) program. The BOND Iron Expert Panel (I-EP) reviewed the extant knowledge regarding iron biology, public health implications, and the relative usefulness of currently available biomarkers of iron status from deficiency to overload. Approaches to assessing intake, including bioavailability, are also covered. The report also covers technical and laboratory considerations for the use of available biomarkers of iron status, and concludes with a description of research priorities along with a brief discussion of new biomarkers with potential for use across the spectrum of activities related to the study of iron in human health.The I-EP concluded that current iron biomarkers are reliable for accurately assessing many aspects of iron nutrition. However, a clear distinction is made between the relative strengths of biomarkers to assess hematological consequences of iron deficiency versus other putative functional outcomes, particularly the relationship between maternal and fetal iron status during pregnancy, birth outcomes, and infant cognitive, motor and emotional development. The I-EP also highlighted the importance of considering the confounding effects of inflammation and infection on the interpretation of iron biomarker results, as well as the impact of life stage. Finally, alternative approaches to the evaluation of the risk for nutritional iron overload at the population level are presented, because the currently designated upper limits for the biomarker generally employed (serum ferritin) may not differentiate between true iron overload and the effects of subclinical inflammation.

Serum proteome profiling in canine idiopathic dilated cardiomyopathy using TMT-based quantitative proteomics approach

Idiopathic dilated cardiomyopathy (iDCM) is a primary myocardial disorder with an unknown aetiology, characterized by reduced contractility and ventricular dilation of the left or both ventricles. Naturally occurring canine iDCM was used herein to identify serum proteomic signature of the disease compared to the healthy state, providing an insight into underlying mechanisms and revealing proteins with biomarker potential. To achieve this, we used high-throughput label-based quantitative LC-MS/MS proteomics approach and bioinformatics analysis of the in silico inferred interactome protein network created from the initial list of differential proteins. To complement the proteomic analysis, serum biochemical parameters and levels of know biomarkers of cardiac function were measured. Several proteins with biomarker potential were identified, such as inter-alpha-trypsin inhibitor heavy chain H4, microfibril-associated glycoprotein 4 and apolipoprotein A-IV, which were validated using an independent method (Western blotting) and showed high specificity and sensitivity according to the receiver operating characteristic curve analysis. Bioinformatics analysis revealed involvement of different pathways in iDCM, such as complement cascade activation, lipoprotein particles dynamics, elastic fibre formation, GPCR signalling and respiratory electron transport chain.

SIGNIFICANCE

Idiopathic dilated cardiomyopathy is a severe primary myocardial disease of unknown cause, affecting both humans and dogs. This study is a contribution to the canine heart disease research by means of proteomic and bioinformatic state of the art analyses, following similar approach in human iDCM research. Importantly, we used serum as non-invasive and easily accessible biological source of information and contributed to the scarce data on biofluid proteome research on this topic. Bioinformatics analysis revealed biological pathways modulated in canine iDCM with potential of further targeted research. Also, several proteins with biomarker potential have been identified and successfully validated.

Laboratory Assessment of Anemia

Anemia is one of the most common health problems in both industrialized and developing countries. It has been recognized by the World Health Organization as an important disorder leading to significant health care burden. Laboratory testing plays a significant role in the diagnosis of most types of anemia since the clinical diagnosis may not always be straightforward, especially with multiple underlying conditions. Once the existence of anemia is established, the cause must be determined to enable selection of a specific and effective therapy. Various hematologic parameters and biochemical tests can be used in combination with patient clinical history to identify the most likely causes of anemia.

Current understanding of iron homeostasis

Iron is an essential trace element, but it is also toxic in excess, and thus mammals have developed elegant mechanisms for keeping both cellular and whole-body iron concentrations within the optimal physiologic range. In the diet, iron is either sequestered within heme or in various nonheme forms. Although the absorption of heme iron is poorly understood, nonheme iron is transported across the apical membrane of the intestinal enterocyte by divalent metal-ion transporter 1 (DMT1) and is exported into the circulation via ferroportin 1 (FPN1). Newly absorbed iron binds to plasma transferrin and is distributed around the body to sites of utilization with the erythroid marrow having particularly high iron requirements. Iron-loaded transferrin binds to transferrin receptor 1 on the surface of most body cells, and after endocytosis of the complex, iron enters the cytoplasm via DMT1 in the endosomal membrane. This iron can be used for metabolic functions, stored within cytosolic ferritin, or exported from the cell via FPN1. Cellular iron concentrations are modulated by the iron regulatory proteins (IRPs) IRP1 and IRP2. At the whole-body level, dietary iron absorption and iron export from the tissues into the plasma are regulated by the liver-derived peptide hepcidin. When tissue iron demands are high, hepcidin concentrations are low and vice versa. Too little or too much iron can have important clinical consequences. Most iron deficiency reflects an inadequate supply of iron in the diet, whereas iron excess is usually associated with hereditary disorders. These disorders include various forms of hemochromatosis, which are characterized by inadequate hepcidin production and, thus, increased dietary iron intake, and iron-loading anemias whereby both increased iron absorption and transfusion therapy contribute to the iron overload. Despite major recent advances, much remains to be learned about iron physiology and pathophysiology.

Labile plasma iron levels predict survival in patients with lower-risk myelodysplastic syndromes

Red blood cell transfusions remain one of the cornerstones in supportive care of lower-risk patients with myelodysplastic syndromes. We hypothesized that patients develop oxidant-mediated tissue injury through the formation of toxic iron species, caused either by red blood cell transfusions or by ineffective erythropoiesis. We analyzed serum samples from 100 lower-risk patients with myelodysplastic syndromes at six-month intervals for transferrin saturation, hepcidin-25, growth differentiation factor 15, soluble transferrin receptor, non-transferrin bound iron and labile plasma iron in order to evaluate temporal changes in iron metabolism and the presence of potentially toxic iron species and their impact on survival. Hepcidin levels were low in 34 patients with ringed sideroblasts compared to 66 patients without. Increases of hepcidin and non-transferrin bound iron levels were visible early in follow-up of all transfusion-dependent patient groups. Hepcidin levels significantly decreased over time in transfusion-independent patients with ringed sideroblasts. Increased soluble transferrin receptor levels in transfusion-independent patients with ringed sideroblasts confirmed the presence of ineffective erythropoiesis and suppression of hepcidin production in these patients. Detectable labile plasma iron levels in combination with high transferrin saturation levels occurred almost exclusively in patients with ringed sideroblasts and all transfusion-dependent patient groups. Detectable labile plasma iron levels in transfusion-dependent patients without ringed sideroblasts were associated with decreased survival. In conclusion, toxic iron species occurred in all transfusion-dependent patients and in transfusion-independent patients with ringed sideroblasts. Labile plasma iron appeared to be a clinically relevant measure for potential iron toxicity and a prognostic factor for survival in transfusion-dependent patients. clinicaltrials.gov Identifier: 00600860.

Serum ferritin is a different predictor from transfusion history for allogeneic transplantation outcome in patients with severe aplastic anemia

OBJECTIVES

Severe aplastic anemia (SAA) patients receive more red blood cell (RBC) transfusions as supportive management. We aim to clarify the associations between transfusion history or pre-transplantation serum ferritin (SF) and the overall survival of allogeneic hematopoietic stem cell transplantation (allo-HSCT) among SAA patients.

MATERIAL AND METHODS

We retrospectively investigated 96 SAA patients undergoing allo-HSCT, and grouped them according to pre-transplantation duration. Pre-transplantation SF, transfused units and other iron-related parameters were collected. Comparisons in transplantation outcomes and complications were made in groups with different SF levels and different transfusion histories.

RESULTS

Among the 96 SAA patients, 45 patients received transplantation within 2 months after diagnosis (short-term pre-transplantation period), and the rest of the patients had long-term pre-transplantation treatment. Among the patients with short-term pre-transplantation treatment, a higher risk of death was seen in the high-ferritin group (p < 0.05). Elevated SF also predicted a trend in incidence of higher bloodstream infection (p = 0.108). Significant correlations were observed between pre-transplantation SF and infection incidence, as well as transfusion history. However, for patients with longer pre-transplantation duration, transfusion history was associated with worse outcome (p = 0.026), in terms of higher incidence of acute graft versus host disease (p = 0.048). High SF was only significantly associated with prolonged RBC transfusion dependence post-transplantation (p = 0.044).

DISCUSSION AND CONCLUSIONS

Transfusion history was a stronger predictor of outcome than SF in patients undergoing transplantation more than 2 months after diagnosis.

Malaria Is More Prevalent Than Iron Deficiency among Anemic Pregnant Women at the First Antenatal Visit in Rural South Kivu

Anemia is common during pregnancy and is associated with poor outcomes. Objectives were not only 1) to determine the prevalence of anemia and iron deficiency (ID) but also 2) to identify other factors associated with anemia in pregnant women from South Kivu province, in the eastern Democratic Republic of Congo. Between December 2013 and March 2014, 531 women attending the first antenatal visit in their second trimester of pregnancy were recruited. Sociodemographic, clinical, and biological data were collected. Hemoglobin (Hb) was determined by a portable photometer (Hemocue^® Hb201+), and anemia was defined as altitude-adjusted Hb < 110 g/L. ID was defined as serum ferritin < 15 μg/L adjusted for inflammation status (C-reactive protein [CRP] > 5 mg/L and/or α-1-acid glycoprotein > 1 g/L) whereas hypoalbuminemia was defined as serum albumin < 35 g/L. A Giemsa-stained blood smear was used to diagnose malaria. The median age (interquartile range ) was 25.5 (21.1-31.3) years, with anemia in 17.6% and ID in 8%. Malaria was present in 7.5% and hypoalbuminemia among 44%. Soluble transferrin receptor concentration was higher in the presence of inflammation and/or malaria. In the final logistic regression model, factors independently associated with anemia were malaria (adjusted odds ratio [aOR]: 11.24 (4.98-25.37) P < 0.001), hypoalbuminemia [aOR: 2.14 (1.27-3.59); P = 0.004] and elevated CRP [aOR: 1.94 (1.10-3.45); P = 0.022]. ID was not highly prevalent and not associated with anemia in our population. Effective control of anemia during pregnancy in this region should consider fighting malaria and other infectious diseases in combination with measures to improve women's nutrition, both before and during pregnancy.

Comparison of Methods Study between a Photonic Crystal Biosensor and Certified ELISA to Measure Biomarkers of Iron Deficiency in Chronic Kidney Disease Patients

The total analytical error of a photonic crystal (PC) biosensor in the determination of ferritin and soluble transferrin receptor (sTfR) as biomarkers of iron deficiency anemia in chronic kidney disease (CKD) patients was evaluated against certified ELISAs. Antigens were extracted from sera of CKD patients using functionalized iron-oxide nanoparticles (fAb-IONs) followed by magnetic separation. Immuno-complexes were recognized by complementary detection Ab affixed to the PC biosensor surface, and their signals were followed using the BIND instrument. Quantification was conducted against actual protein standards. Total calculated error (TEcalc) was estimated based on systematic (SE) and random error (RE) and compared against total allowed error (TEa) based on established quality specifications. Both detection platforms showed adequate linearity, specificity, and sensitivity for biomarkers. Means, SD, and CV were similar between biomarkers for both detection platforms. Compared to ELISA, inherent imprecision was higher on the PC biosensor for ferritin, but not for sTfR. High SE or RE in the PC biosensor when measuring either biomarker resulted in TEcalc higher than the TEa. This did not influence the diagnostic ability of the PC biosensor to discriminate CKD patients with low iron stores. The performance of the PC biosensor is similar to certified ELISAs; however, optimization is required to reduce TEcalc.

The Impact of Iron Overload in Acute Leukemia: Chronic Inflammation, But Not the Presence of Nontransferrin Bound Iron is a Determinant of Oxidative Stress

In the literature, studies on the oxidant effects of nontransferrin bound iron [NTBI (eLPI assay)] during chemotherapy of acute lymphoblastic leukemia and acute myeloblastic leukemia are lacking. We established NTBI and oxidative stress determinants (OSD), iron parameters, high-sensitive C-reactive protein (hs-CRP) levels, liver tests, cumulative chemotherapeutic doses, and transfused blood in 36 children with acute leukemia throughout chemotherapy. These parameters were determined at the beginning and end of chemotherapy blocks (11 time points) and in 20 healthy children using enzyme-linked immunosorbent assay, and colorimetric and fluorometric enzymatic methods. In acute lymphoblastic leukemia, NTBI, OSD, and hs-CRP were higher than controls at 4/11, 7/11, and 9/11 time points (P<0.05). At 3 time points, NTBI and OSD concurrently increased. Ferritin, soluble transferrin receptor, serum iron, and transferrin saturation were higher than in controls at 5 to 11/11 time points (P<0.05). Those with NTBI had higher iron parameters than those without NTBI (P<0.05), but showed similar OSD, hs-CRP, liver enzymes, cumulative chemotherapeutics, and transfused blood (P>0.05). OSD did not correlate with NTBI, but correlated with hs-CRP. In conclusion, NTBI is a poor predictor of OSD in acute leukemia possibly because of the heterogeneity of NTBI and chronic inflammation. Further studies are needed to delineate the pathophysiology of these diseases.

Adjusting soluble transferrin receptor concentrations for inflammation: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project

Background: Iron deficiency is thought to be one of the most prevalent micronutrient deficiencies globally, but an accurate assessment in populations who are frequently exposed to infections is impeded by the inflammatory response, which causes iron-biomarker alterations.Objectives: We assessed the relation between soluble transferrin receptor (sTfR) concentrations and inflammation and malaria in preschool children (PSC) (age range: 6-59 mo) and women of reproductive age (WRA) (age range: 15-49 y) and investigated adjustment algorithms to account for these effects.Design: Cross-sectional data from the Biomarkers Reflecting the Inflammation and Nutritional Determinants of Anemia (BRINDA) project from 11,913 PSC in 11 surveys and from 11,173 WRA in 7 surveys were analyzed individually and combined with the use of a meta-analysis. The following 3 adjustment approaches were compared with estimated iron-deficient erythropoiesis (sTfR concentration >8.3 mg/L): 1) the exclusion of individuals with C-reactive protein (CRP) concentrations >5 mg/L or α-1-acid glycoprotein (AGP) concentrations >1 g/L, 2) the application of arithmetic correction factors, and 3) the use of regression approaches.Results: The prevalence of elevated sTfR concentrations incrementally decreased as CRP and AGP deciles decreased for PSC and WRA, but the effect was more pronounced for AGP than for CRP. Depending on the approach used to adjust for inflammation, the estimated prevalence of iron-deficient erythropoiesis decreased by 4.4-14.6 and 0.3-9.5 percentage points in PSC and WRA, respectively, compared with unadjusted values. The correction-factor approach yielded a more modest reduction in the estimated prevalence of iron-deficient erythropoiesis than did the regression approach. Mostly, adjustment for malaria in addition to AGP did not significantly change the estimated prevalence of iron-deficient erythropoiesis.Conclusions: sTfR may be useful to assess iron-deficient erythropoiesis, but inflammation influences its interpretation, and adjustment of sTfR for inflammation and malaria should be considered. More research is warranted to evaluate the proposed approaches in different settings, but this study contributes to the evidence on how and when to adjust sTfR for inflammation and malaria.