Iron Metabolism: An Emerging Therapeutic Target in Critical Illness

Ferritin Levels on Hospital Admission Predict Hypoxic-Ischemic Encephalopathy in Patients After Out-of-Hospital Cardiac Arrest: A Prospective Observational Single-Center Study

AIM

Out-of-hospital cardiac arrest (OHCA) is a major health concern in Western societies. Poor outcome after OHCA is determined by the extent of hypoxic-ischemic encephalopathy (HIE). Dysregulation of iron metabolism has prognostic relevance in patients with ischemic stroke and sepsis. The aim of this study was to determine whether serum iron parameters help to estimate outcomes after OHCA.

METHODS

In this prospective single-center study, 70 adult OHCA patients were analyzed. Serum ferritin, iron, transferrin (TRF), and TRF saturation (TRFS) were measured in blood samples drawn on day 0 (admission), day 2, day 4, and 6 months after the return of spontaneous circulation (ROSC). The association of 4 iron parameters with in-hospital mortality, neurological outcome (cerebral performance category [CPC]), and HIE was investigated by receiver operating characteristics and multivariate regression analyses.

RESULTS

OHCA subjects displayed significantly increased serum ferritin levels on day 0 and lowered iron, TRF, and TRFS on days 2 and 4 after ROSC, as compared to concentrations measured at a 6-month follow-up. Iron parameters were not associated with in-hospital mortality or neurological outcomes according to the CPC. Ferritin on admission was an independent predictor of features of HIE on cranial computed tomography and death due to HIE.

CONCLUSION

OHCA is associated with alterations in iron metabolism that persist for several days after ROSC. Ferritin on admission can help to predict HIE.

Deciphering the iron enigma: Navigating the complexities of iron metabolism in critical illness

Iron is a double-edged sword! Despite being essential for numerous physiological processes of the body, a dysregulated iron metabolism can result in tissue damage, exaggerated inflammatory response, and increased susceptibility to infection with certain pathogens that thrive in iron-rich environment. During sepsis, there is an alteration of iron metabolism, leading to increased transport and uptake into cells. This increase in labile iron may cause oxidative damage and cellular injury (ferroptosis) which progresses as the disease worsens. Critically ill patients are often complicated with systemic inflammation which may contribute to multiple organ dysfunction syndrome or sepsis, a common cause of mortality in intensive care unit. Originally, ferritin was known to play an important role in the hematopoietic system for its iron storage capacity. Recently, its role has emerged as a predictor of poor prognosis in chronic inflammation and critical illnesses. Apart from predicting the disease outcome, serum ferritin can potentially reflect disease activity as well.

Severe iron-deficiency anemia after short-term moderate consumption of green tea in woman: A rare case report

While the mechanisms by which tea consumption hinders iron absorption are well understood, tea-related anemia usually stems from prolonged and excessive intake, which obstructs iron absorption and depletes the body's iron reserves. Consequently, it is uncommon for hemoglobin levels to plummet by 6.9 g/dl solely due to moderate tea consumption over a span of three months. We present a case of severe iron-deficiency anemia in a woman following short-term, moderate green tea consumption. After modifying her tea intake regimen, there was no recurrence of anemia. Clinicians should be mindful that even moderate tea consumption can precipitate severe iron-deficiency anemia in individuals particularly vulnerable to its effects on iron absorption.

Iron Metabolism in the Recovery Phase of Critical Illness with a Focus on Sepsis

Iron is an essential nutrient for humans and microbes, such as bacteria. Iron deficiency commonly occurs in critically ill patients, but supplementary iron therapy is not considered during the acute phase of critical illness since it increases iron availability for invading microbes and oxidative stress. However, persistent iron deficiency in the recovery phase is harmful and has potential adverse outcomes such as cognitive dysfunction, fatigue, and cardiopulmonary dysfunction. Therefore, it is important to treat iron deficiency quickly and efficiently. This article reviews current knowledge about iron-related biomarkers in critical illness with a focus on patients with sepsis, and provides possible criteria to guide decision-making for iron supplementation in the recovery phase of those patients.

Type 2 diabetic mellitus related osteoporosis: focusing on ferroptosis

With the aging global population, type 2 diabetes mellitus (T2DM) and osteoporosis(OP) are becoming increasingly prevalent. Diabetic osteoporosis (DOP) is a metabolic bone disorder characterized by abnormal bone tissue structure and reduced bone strength in patients with diabetes. Studies have revealed a close association among diabetes, increased fracture risk, and disturbances in iron metabolism. This review explores the concept of ferroptosis, a non-apoptotic cell death process dependent on intracellular iron, focusing on its role in DOP. Iron-dependent lipid peroxidation, particularly impacting pancreatic β-cells, osteoblasts (OBs) and osteoclasts (OCs), contributes to DOP. The intricate interplay between iron dysregulation, which comprises deficiency and overload, and DOP has been discussed, emphasizing how excessive iron accumulation triggers ferroptosis in DOP. This concise overview highlights the need to understand the complex relationship between T2DM and OP, particularly ferroptosis. This review aimed to elucidate the pathogenesis of ferroptosis in DOP and provide a prospective for future research targeting interventions in the field of ferroptosis.

Clinical Evidence on the Potential Beneficial Effects of Diet and Dietary Supplements against COVID-19 Infection Risk and Symptoms' Severity

BACKGROUND

Diet and dietary supplements aim to add trace elements, vitamins, and minerals to the body to improve human health and boost the immune system. In the previous few years, the new SARS-CoV-2 coronavirus strain has been threatening the health of individuals and public health more broadly, with rates of intensive care unit cases on the rise, while long-term COVID-19 complications are persisting until today. In the peculiar circumstances of the COVID-19 pandemic, in combination with disease prevention techniques, the strengthening of the immune system is considered particularly important to enable it to effectively respond to and eliminate the SARS-CoV-2 viral pathogen in the event of infection. The purpose of the current literature review is to thoroughly summarize and critically analyze the current clinical data concerning the potential beneficial effects of diet and dietary supplements against COVID-19 infection risk and symptoms' severity. The micronutrients/supplements examined in this study in relation to COVID-19 infection are vitamins A, B, C, and D, zinc, selenium, magnesium, iron, omega-3 fatty acids, glutamine, resveratrol, beta-glucans, and probiotics. The potential effects of dietary patterns such as the Mediterranean diet against SARS-CoV-2 infection risk and symptoms' severity were also analyzed. Our literature review suggests that micro- and macronutrient supplementation and a healthy diet and lifestyle may provide support to immune system function, with beneficial effects both before and during SARS-CoV-2 infection. However, additional studies are recommended to draw safe conclusions and formulate dietary recommendations concerning dietary supplements and their possible effects on preventing and co-treating COVID-19 disease.

Iron as an emerging therapeutic target in critically ill patients

The multiple roles of iron in the body have been known for decades, particularly its involvement in iron overload diseases such as hemochromatosis. More recently, compelling evidence has emerged regarding the critical role of non-transferrin bound iron (NTBI), also known as catalytic iron, in the care of critically ill patients in intensive care units (ICUs). These trace amounts of iron constitute a small percentage of the serum iron, yet they are heavily implicated in the exacerbation of diseases, primarily by catalyzing the formation of reactive oxygen species, which promote oxidative stress. Additionally, catalytic iron activates macrophages and facilitates the growth of pathogens. This review aims to shed light on this underappreciated phenomenon and explore the various common sources of NTBI in ICU patients, which lead to transient iron dysregulation during acute phases of disease. Iron serves as the linchpin of a vicious cycle in many ICU pathologies that are often multifactorial. The clinical evidence showing its detrimental impact on patient outcomes will be outlined in the major ICU pathologies. Finally, different therapeutic strategies will be reviewed, including the targeting of proteins involved in iron metabolism, conventional chelation therapy, and the combination of renal replacement therapy with chelation therapy.

Iron and erythropoietin to heal and recover after intensive care (ITHRIVE): A pilot randomised clinical trial

Objective

To determine the feasibility of a pivotal randomised clinical trial of intravenous (IV) iron and erythropoietin in adult survivors of critical illness with anaemia requiring treatment in the intensive care unit.

Design

An investigator-initiated, parallel group, placebo-controlled, randomised feasibility trial.

Setting

A tertiary intensive care unit (ICU) in Perth, Western Australia.

Participants

Adults with anaemia (haemoglobin <100 g/L), requiring ICU-level care for more than 48 h, and likely to be ready for ICU discharge within 24 h.

Interventions

A single dose of IV ferric carboxymaltose and Epoetin alfa (active group) or an equal volume of 0.9% saline (placebo group).

Main outcome measures

Study feasibility was considered met if the pilot achieved a recruitment rate of ≥2 participants per site per month, ≥90% of participants received their allocated study treatment, and≥ 90% of participants were followed up for the proposed pivotal trial primary outcome - days alive and at home to day 90 (DAH90).

Results

The 40-participant planned sample size included twenty in each group and was enrolled between 1/9/2021 and 2/3/2022. Participants spent a median of 3.4 days (interquartile range 2.8-5.1) in the ICU prior to enrolment and had a mean baseline haemoglobin of 83.7 g/L (standard deviation 6.7). The recruitment rate was 6.7 participants per month [95% confidence interval (CI) 4.8-9.0], DAH90 follow-up was 100% (95% CI 91.2%-100%), and 39 (97.5%, 95% CI 86.8%-99.9%) participants received the allocated study intervention. No serious adverse events were reported.

Conclusion

The iron and erythropoietin to heal and recover after intensive care (ITHRIVE) pilot demonstrated feasibility based on predefined participant recruitment, study drug administration, and follow-up thresholds.

Iron and iron-related proteins in COVID-19

COVID-19 can cause detrimental effects on health. Vaccines have helped in reducing disease severity and transmission but their long-term effects on health and effectiveness against future viral variants remain unknown. COVID-19 pathogenesis involves alteration in iron homeostasis. Thus, a contextual understanding of iron-related parameters would be very valuable for disease prognosis and therapeutics.Accordingly, we reviewed the status of iron and iron-related proteins in COVID-19. Iron-associated alterations in COVID-19 reported hitherto include anemia of inflammation, low levels of serum iron (hypoferremia), transferrin and transferrin saturation, and high levels of serum ferritin (hyperferritinemia), hepcidin, lipocalin-2, catalytic iron, and soluble transferrin receptor (in ICU patients). Hemoglobin levels can be low or normal, and compromised hemoglobin function has been proposed. Membrane-bound transferrin receptor may facilitate viral entry, so it acts as a potential target for antiviral therapy. Lactoferrin can provide natural defense by preventing viral entry and/or inhibiting viral replication. Serum iron and ferritin levels can predict COVID-19-related hospitalization, severity, and mortality. Serum hepcidin and ferritin/transferrin ratio can predict COVID-19 severity. Here, serum levels of these iron-related parameters are provided, caveats of iron chelation for therapy are discussed and the interplay of these iron-related parameters in COVID-19 is explained.This synopsis is crucial as it clearly presents the iron picture of COVID-19. The information may assist in disease prognosis and/or in formulating iron-related adjunctive strategies that can help reduce infection/inflammation and better manage COVID-19 caused by future variants. Indeed, the current picture will augment as more is revealed about these iron-related parameters in COVID-19.

The role of ferroptosis in metabolic diseases

The annual incidence of metabolic diseases such as diabetes, non-alcoholic fatty liver disease (NAFLD), osteoporosis, and atherosclerosis (AS) is increasing, resulting in a heavy burden on human health and the social economy. Ferroptosis is a novel form of programmed cell death driven by iron-dependent lipid peroxidation, which was discovered in recent years. Emerging evidence has suggested that ferroptosis contributes to the development of metabolic diseases. Here, we summarize the mechanisms and molecular signaling pathways involved in ferroptosis. Then we discuss the role of ferroptosis in metabolic diseases. Finally, we analyze the potential of targeting ferroptosis as a promising therapeutic approach for metabolic diseases.

The Role of Nutrition in Mitigating the Effects of COVID-19 from Infection through PASC

The expansive and rapid spread of the SARS-CoV-2 virus has resulted in a global pandemic of COVID-19 infection and disease. Though initially perceived to be acute in nature, many patients report persistent and recurrent symptoms beyond the infectious period. Emerging as a new epidemic, "long-COVID", or post-acute sequelae of coronavirus disease (PASC), has substantially altered the lives of millions of people globally. Symptoms of both COVID-19 and PASC are individual, but share commonality to established respiratory viruses, which include but are not limited to chest pain, shortness of breath, fatigue, along with adverse metabolic and pulmonary health effects. Nutrition plays a critical role in immune function and metabolic health and thus is implicated in reducing risk or severity of symptoms for both COVID-19 and PASC. However, despite the impact of nutrition on these key physiological functions related to COVID-19 and PASC, the precise role of nutrition in COVID-19 infection and PASC onset or severity remains to be elucidated. This narrative review will discuss established and emerging nutrition approaches that may play a role in COVID-19 and PASC, with references to the established nutrition and clinical practice guidelines that should remain the primary resources for patients and practitioners.

Effect of Deferoxamine on Post-Transfusion Iron, Inflammation, and In Vitro Microbial Growth in a Canine Hemorrhagic Shock Model: A Randomized Controlled Blinded Pilot Study

Red blood cell (RBC) transfusion is associated with recipient inflammation and infection, which may be triggered by excessive circulating iron. Iron chelation following transfusion may reduce these risks. The aim of this study was to evaluate the effect of deferoxamine on circulating iron and inflammation biomarkers over time and in vitro growth of Escherichia coli (E. coli) following RBC transfusion in dogs with atraumatic hemorrhage. Anesthetized dogs were subject to atraumatic hemorrhage and transfusion of RBCs, then randomized to receive either deferoxamine or saline placebo of equivalent volume (n = 10 per group) in a blinded fashion. Blood was sampled before hemorrhage and then 2, 4, and 6 h later. Following hemorrhage and RBC transfusion, free iron increased in all dogs over time (both p < 0.001). Inflammation biomarkers interleukin-6 (IL6), CXC motif chemokine-8 (CXCL8), interleukin-10 (IL10), and keratinocyte-derived chemokine (KC) increased in all dogs over time (all p < 0.001). Logarithmic growth of E. coli clones within blood collected 6 h post-transfusion was not different between groups. Only total iron-binding capacity was different between groups over time, being significantly increased in the deferoxamine group at 2 and 4 h post-transfusion (both p < 0.001). In summary, while free iron and inflammation biomarkers increased post-RBC transfusion, deferoxamine administration did not impact circulating free iron, inflammation biomarkers, or in vitro growth of E. coli when compared with placebo.

Investigation of Serum Ferritin for the Prediction of COVID-19 Severity and Mortality: A Cross-Sectional Study

BACKGROUND

Acute respiratory failure develops quickly in patients with a severe form of coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome Coronavirus 2 (SARS‑CoV‑2). Despite being commonly acknowledged as a measure of the body's overall iron storage, ferritin's predictive value is associated with COVID-19.

OBJECTIVE

This study aimed to evaluate the relationship between COVID-19 and serum ferritin levels as the biochemical markers of SARS-CoV-2 infection in Sulaymaniyah, Iraq.

METHOD

A biochemical test was performed at Baxshin Hospital in the period from February 2022 to April 2022. It was performed on a total of 85 patients (63.53% males and 36.47% females), ranging in age from 25 to 79 years old, with an average age of 48.4 years old. The patient's blood samples were taken to screen for ferritin levels.

RESULT

The resulting outcome of this work is high serum ferritin levels for the majority of infected patients. Overall, there is a significant difference between male and female serum ferritin observed with a p-value < 0.05. The median interquartile range (IQR) of serum ferritin was 896 ng/mL for males, while it was only 611 ng/mL for females. The current study showed that age level has a great effect on elevated ferritin levels. It has been discovered that gender impacts increasing ferritin levels; 62% were found to be men and 38% were found to be women, with average ferritin levels of 1111 ng/mL and 712.8 ng/mL, respectively.

CONCLUSION

SARS-CoV-2 infection causes significant laboratory abnormalities, including a high level of serum ferritin.

Ferritin thresholds for cardiac and liver hemosiderosis in β-thalassemia patients: a diagnostic accuracy study

Ferritin is frequently used to screen some dire consequences of iron overload in β-thalassemia patients. The study aimed to define the best cutoff point of ferritin to screen for cardiac and liver hemosiderosis in these cases. This was a registry-based study on β-thalassemia patients living throughout Mazandaran province, Iran (n = 1959). In this diagnostic research, the index test was ferritin levels measured by a chemiluminescent immunoassay. As a reference test, T2*-weighted magnetic resonance imaging (T2*-weighted MRI) was applied to determine cardiac and liver hemosiderosis. A cutoff point of 2027 ng/mL for ferritin showed a sensitivity of 50%, specificity 77.4%, PPV 42.1%, and NPV 82.5% for cardiac hemosiderosis (area under curve [AUC] 0.66, 95% CI 0.60-0.71, adjusted odds ratio [OR] 2.05, 95% CI 1.05-4.01). At an optimum cutoff point of 1090 ng/mL, sensitivity 66.7%, specificity 68%, PPV 82.9%, and NPV 46.8% for liver hemosiderosis were estimated (AUC 0.68, 95% CI 0.63-0.73, adjusted OR 3.93, 95% CI 2.02-7.64. The likelihood of cardiac hemosiderosis serum ferritin levels below 2027 ng/mL is 17.5%. Moreover, 82.9% of β-thalassemia patients with serum ferritin levels above 1090 ng/mL may suffer from liver hemosiderosis, regardless of the grades.

Iron in Alzheimer's Disease: From Physiology to Disease Disabilities

Reactive oxygen species (ROS) play a key role in the neurodegeneration processes. Increased oxidative stress damages lipids, proteins, and nucleic acids in brain tissue, and it is tied to the loss of biometal homeostasis. For this reason, attention has been focused on transition metals involved in several biochemical reactions producing ROS. Even though a bulk of evidence has uncovered the role of metals in the generation of the toxic pathways at the base of Alzheimer's disease (AD), this matter has been sidelined by the advent of the Amyloid Cascade Hypothesis. However, the link between metals and AD has been investigated in the last two decades, focusing on their local accumulation in brain areas known to be critical for AD. Recent evidence revealed a relation between iron and AD, particularly in relation to its capacity to increase the risk of the disease through ferroptosis. In this review, we briefly summarize the major points characterizing the function of iron in our body and highlight why, even though it is essential for our life, we have to monitor its dysfunction, particularly if we want to control our risk of AD.

Iron and iron-related proteins in alcohol consumers: cellular and clinical aspects

Alcohol-associated liver disease (ALD) is one of the most common chronic liver diseases. Its pathological spectrum includes the overlapping stages of hepatic steatosis/steatohepatitis that can progress to liver fibrosis and cirrhosis; both are risk factors for hepatocellular carcinoma. Moreover, ALD diagnosis and management pose several challenges. The early pathological stages are reversible by alcohol abstinence, but these early stages are often asymptomatic, and currently, there is no specific laboratory biomarker or diagnostic test that can confirm ALD etiology. Alcohol consumers frequently show dysregulation of iron and iron-related proteins. Examination of iron-related parameters in this group may aid in early disease diagnosis and better prognosis and management. For this, a coherent overview of the status of iron and iron-related proteins in alcohol consumers is essential. Therefore, here, we collated and reviewed the alcohol-induced alterations in iron and iron-related proteins. Reported observations include unaltered, increased, or decreased levels of hemoglobin and serum iron, increments in intestinal iron absorption (facilitated via upregulations of duodenal divalent metal transporter-1 and ferroportin), serum ferritin and carbohydrate-deficient transferrin, decrements in serum hepcidin, decreased or unaltered levels of transferrin, increased or unaltered levels of transferrin saturation, and unaltered levels of soluble transferrin receptor. Laboratory values of iron and iron-related proteins in alcohol consumers are provided for reference. The causes and mechanisms underlying these alcohol-induced alterations in iron parameters and anemia in ALD are explained. Notably, alcohol consumption by hemochromatosis (iron overload) patients worsens disease severity due to the synergistic effects of excess iron and alcohol.

Efficacy and Safety of Intravenous Iron Therapy for Treating Anaemia in Critically ill Adults: A Rapid Systematic Review With Meta-Analysis

Our objective was to systematically evaluate the efficacy and safety of intravenous (IV) iron therapy for treating anaemia in critically ill adults (>16 years) admitted to intensive care or high dependency units. We excluded quasi-RCTs and other not truly randomised trials. We searched 7 electronic databases (including CENTRAL, MEDLINE, and Embase) using a pre-defined search strategy from inception to June 14, 2021. One reviewer screened, extracted, and analysed data, with verification by a second reviewer of all decisions. We used Cochrane risk of bias (ROB) 1 and GRADE to assess the certainty of the evidence. We reported 3 comparisons across 1198 patients, in 8 RCTs: (1) IV iron vs control (7 RCTs, 748 participants); our primary outcome (hemoglobin (Hb) concentration at 10 to 30 days) was reported in 7 of the 8 included trials. There was evidence of an effect (very-low certainty) in favour of IV iron over control in the main comparison only (6 RCTs, n = 528, mean difference (MD) 0.52g/dL [95%CI 0.23, 0.81], P = .0005). For the remaining outcomes there was no evidence of an effect in either direction (low certainty of evidence for Hb concentration at <10 days; very-low certainty of evidence for hospital duration, ICU duration, hospital readmission, infection, mortality; HRQoL outcomes were not GRADED). (2) IV iron + subcutaneous erythropoietin (EPO) vs control (2 RCTs, 104 participants); reported outcomes showed no evidence of effect in either direction, based on very-low certainty evidence (Hb concentration at 10-30 days, and <10 days, infection, mortality). (3) Hepcidin-guided treatment with IV iron or iron+ EPO vs standard care (1 RCT, 399 participants) reported evidence of an effect in favour of the intervention for 90-day mortality (low certainty of evidence), but no other group differences for the reported outcomes (low certainty evidence for Hb concentration at 10-30 days, hospital duration; HRQoL was not GRADED). The evidence across all comparisons was downgraded for high and unclear ROB for lack of blinding, incomplete outcome data, baseline imbalance, and imprecision around the estimate (wide CIs and small sample size). In conclusion, the current evidence continues to support further investigation into the role for iron therapy in increasing Hb in critically ill patients. Recent, small, trials have begun to focus on patient-centred outcomes but a large, well conducted, and adequately powered trial is needed to inform clinical practice.

Acute heart failure and iron deficiency: a prospective, multicentre, observational study

Aims

The prevalence and the natural course of iron deficiency (ID) in acute heart failure (AHF) are still unclear. We investigated the prevalence of ID in unselected patients admitted with AHF on admission, at discharge and up to 3 months thereafter.

Methods and results

In this prospective, multicentre, observational study, 742 patients admitted with AHF were enrolled. The main study outcome was the percentage of patients with ID (ferritin <100 μg/L = absolute ID or ferritin 100–299 μg/L and transferrin saturation <20% = functional ID) at admission (T0), after clinical stabilization prior to discharge (T1), and 10 ± 6 weeks after discharge (T2). At T0, ID was present in 71.8% of the patients (44.1% absolute and 27.7% functional ID). At T1 and T2, ID was present in 56.4% (32.4% absolute and 24% functional ID) and 50.3% (36.8% absolute and 13.5% functional ID), respectively. Absolute ID persisted from T0 to T2 in 66% of the patients, while functional ID resolved in 56% of the patients. Ferritin (median [interquartile range] 124 μg/L [56–247] to 150 μg/L [73–277]), transferrin saturation (15% [10–20] to 18% [12–27]), and iron levels (9 μmol/L [6–13] to 11 μmol/L [8–16]) increased significantly (all P < 0.001) from T0 to T1. Transferrin saturation (to 21% [15–29]) and iron levels (to 13 μmol/L [9–17]) also increased significantly (both P < 0.01) from T1 to T2 without iron supplementation.

Conclusions

Iron deficiency is highly prevalent in patients with AHF, but resolves during treatment in some patients, even without iron supplementation. Absolute ID is more likely to persist over time, whereas functional ID often resolves during treatment of AHF, representing probably a reduced iron availability rather than a true deficiency.

Risk of Infection Associated With Administration of Intravenous Iron: A Systematic Review and Meta-analysis

IMPORTANCE

Intravenous iron is recommended by many clinical guidelines based largely on its effectiveness in reducing anemia. However, the association with important safety outcomes, such as infection, remains uncertain.

OBJECTIVE

To examine the risk of infection associated with intravenous iron compared with oral iron or no iron.

DATA SOURCES

Medline, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for randomized clinical trials (RCTs) from 1966 to January 31, 2021. Ongoing trials were sought from ClinicalTrials.gov, CENTRAL, and the World Health Organization International Clinical Trials Search Registry Platform.

STUDY SELECTION

Pairs of reviewers identified RCTs that compared intravenous iron with oral iron or no iron across all patient populations, excluding healthy volunteers. Nonrandomized studies published since January 1, 2007, were also included. A total of 312 full-text articles were assessed for eligibility.

DATA EXTRACTION AND SYNTHESIS

Data extraction and risk of bias assessments were performed according to the Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA) and Cochrane recommendations, and the quality of evidence was assessed using the GRADE (Grades of Recommendation, Assessment, Development, and Evaluation) approach. Two reviewers extracted data independently. A random-effects model was used to synthesize data from RCTs. A narrative synthesis was performed to characterize the reporting of infection.

MAIN OUTCOMES AND MEASURES

The primary outcome was risk of infection. Secondary outcomes included mortality, hospital length of stay, and changes in hemoglobin and red blood cell transfusion requirements. Measures of association were reported as risk ratios (RRs) or mean differences.

RESULTS

A total of 154 RCTs (32 920 participants) were included in the main analysis. Intravenous iron was associated with an increased risk of infection when compared with oral iron or no iron (RR, 1.17; 95% CI, 1.04-1.31; I2 = 37%; moderate certainty of evidence). Intravenous iron also was associated with an increase in hemoglobin (mean difference, 0.57 g/dL; 95% CI, 0.50-0.64 g/dL; I2 = 94%) and a reduction in the risk of requiring a red blood cell transfusion (RR, 0.93; 95% CI, 0.76-0.89; I2 = 15%) when compared with oral iron or no iron. There was no evidence of an effect on mortality or hospital length of stay.

CONCLUSIONS AND RELEVANCE

In this large systematic review and meta-analysis, intravenous iron was associated with an increased risk of infection. Well-designed studies, using standardized definitions of infection, are required to understand the balance between this risk and the potential benefits.

Osteosarcoma in Children: Not Only Chemotherapy

Osteosarcoma (OS) is the most severe bone malignant tumor, responsible for altered osteoid deposition and with a high rate of metastasis. It is characterized by heterogeneity, chemoresistance and its interaction with bone microenvironment. The 5-year survival rate is about 67% for patients with localized OS, while it remains at 20% in case of metastases. The standard therapy for OS patients is represented by neoadjuvant chemotherapy, surgical resection, and adjuvant chemotherapy. The most used chemotherapy regimen for children is the combination of high-dose methotrexate, doxorubicin, and cisplatin. Considered that the necessary administration of high-dose chemotherapy is responsible for a lot of acute and chronic side effects, the identification of novel therapeutic strategies to ameliorate OS outcome and the patients' life expectancy is necessary. In this review we provide an overview on new possible innovative therapeutic strategies in OS.

Physiological and pathophysiological mechanisms of hepcidin regulation: clinical implications for iron disorders

The discovery of hepcidin has provided a solid foundation for understanding the mechanisms of systemic iron homeostasis and the aetiologies of iron disorders. Hepcidin assures the balance of circulating and stored iron levels for multiple physiological processes including oxygen transport and erythropoiesis, while limiting the toxicity of excess iron. The liver is the major site where regulatory signals from iron, erythropoietic drive and inflammation are integrated to control hepcidin production. Pathologically, hepcidin dysregulation by genetic inactivation, ineffective erythropoiesis, or inflammation leads to diseases of iron deficiency or overload such as iron-refractory iron-deficiency anaemia, anaemia of inflammation, iron-loading anaemias and hereditary haemochromatosis. In the present review, we discuss recent insights into the molecular mechanisms governing hepcidin regulation, how these pathways are disrupted in iron disorders, and how this knowledge is being used to develop novel diagnostic and therapeutic strategies.

Hepcidin Increases Cytokines in Alzheimer's Disease and Down's Syndrome Dementia: Implication of Impaired Iron Homeostasis in Neuroinflammation

The liver-derived hormone hepcidin, a member of the defensin family of antimicrobial peptides, plays an important role in host defense and innate immunity due to its broad antibacterial and antiviral properties. Ferritin, an iron storage protein is often associated with iron deficiency, hypoferritinemia, hypoxia, and immune complications, which are all significant concerns for systemic infection in Alzheimer’s disease (AD) and Down’s syndrome (DS) dementia. Serum and post-mortem brain samples were collected from AD, DS and age-matched control subjects. Serum samples were analyzed with ELISA for ferritin, hepcidin and IL-6. Additionally, post-mortem brain sections were assessed by immunohistochemistry for iron-related and inflammatory proteins. A significant increase in serum hepcidin levels was found in DS, compared to controls and AD subjects (p < 0.0001). Hepcidin protein was visible in the epithelial cells of choroid plexus, meningeal macrophages and in the astrocytes close to the endothelium of blood vessels. Hepcidin co-localized with IL-6, indicating its anti-inflammatory properties. We found significant correlation between hypoferritinemia and elevated levels of serum hepcidin in AD and DS. Hepcidin can be transported via macrophages and the majority of the vesicular hepcidin enters the brain via a compromised blood brain barrier (BBB). Our findings provide further insight into the molecular implications of the altered iron metabolism in acute inflammation, and can aid towards the development of preventive strategies and novel treatments in the fight against neuroinflammation.

Anaemia among intensive care unit survivors and association with days alive and at home: an observational study

Anaemia is highly prevalent at the time of intensive care unit discharge and is persistent for a high proportion of intensive care unit survivors. Whether anaemia is a driver of impaired recovery after critical illness is uncertain. The aim of this study was to test the hypothesis that, in adult intensive care survivors, anaemia at the time of intensive care unit discharge independently predicts decreased days at home-90. This retrospective cohort study was conducted in a tertiary intensive care unit in Perth, Western Australia. All patients aged ≥ 16 years, discharged alive from their index intensive care unit admission and without documented treatment limitations were included. Median (IQR [range]) age of the 6358 participants was 61 (46-72 [16-95]) years and included 3385 (53.2%) unplanned admissions. Intensive care unit discharge with a haemoglobin concentration < 100 g.l^-1 occurred in 2886 (45.4%) patients, a threshold that identified a cohort with significantly lower days at home-90 (median (IQR [range]) 80 (64-85 [0-90]) days vs. 85 (77-88 [0-90]) days (median difference 5 days, 95%CI 4.4-5.5, p < 0.0001). The association followed a severity-response relationship with more severe anaemia predicting lower days at home-90. When accounting for prespecified covariates including admission haemoglobin concentration and red blood cell transfusion, anaemia at intensive care unit discharge remained a significant predictor of decreased days at home-90, relative risk 0.96 (0.93-0.98), p < 0.002. These findings support the need for interventional trials investigating whether this risk is modifiable.

Strengthening the immunity of the Swiss population with micronutrients: A narrative review and call for action

BACKGROUND

The enormous health impact of the COVID-19 pandemic has refocused attention on measures to optimize immune function and vaccine response. Dietary deficiencies of micronutrients can weaken adaptive immunity. The aim of this review was to examine links between micronutrients, immune function and COVID-19 infection, with a focus on nutritional risks in subgroups of the Swiss population.

METHODS

Scoping review on the associations between selected micronutrients (vitamins D and C, iron, selenium, zinc, and n-3 PUFAs) and immunity, with particular reference to the Swiss population. These nutrients were chosen because previous EFSA reviews have concluded they play a key role in immunity.

RESULTS

The review discusses the available knowledge on links between sufficient nutrient status, optimal immune function, and prevention of respiratory tract infections. Because of the rapid spread of the COVID-19 pandemic, controlled intervention studies of micronutrients in the context of COVID-19 infection are now underway, but evidence is not yet available to draw conclusions. The anti-inflammatory properties of n-3 PUFAs are well established. In Switzerland, several subgroups of the population are at clear risk of nutrient deficiencies; e.g., older adults, multiple comorbidities, obesity, pregnancy, and institutionalized. Low intakes of n-3 PUFA are present in a large proportion of the population.

CONCLUSION

There are clear and strong relationships between micronutrient and n-3 PUFA status and immune function, and subgroups of the Swiss population are at risk for deficient intakes. Therefore, during the COVID-19 pandemic, as a complement to a healthy and balanced diet, it may be prudent to consider supplementation with a combination of moderate doses of Vitamins C and D, as well as of Se, Zn and n-3 PUFA, in risk groups.

The effect of iron deficiency and anaemia on women's health

Iron deficiency and anaemia are global health problems and major causes of morbidity in women. Current definitions of anaemia in women are historic and have been challenged by recent data from observational studies. Menstrual loss, abnormal uterine bleeding and pregnancy put women at risk of developing iron deficiency which can result in severe fatigue, reduced exercise capacity and poor work performance. Iron deficiency and anaemia during pregnancy are associated with adverse maternal and fetal outcomes, including neurocognitive deficits in children born to iron-deficient mothers. Both iron deficiency and anaemia are common in women undergoing surgery but their association with poor outcomes remains uncertain. The enduring burden of iron deficiency and anaemia in women suggests that current strategies for recognition, prevention and treatment are limited in their utility. Improvements in our understanding of iron homeostasis and the development of new iron preparations, which are better absorbed with fewer side-effects, may improve therapeutic effectiveness of oral iron. Intravenous iron is efficacious for correcting anaemia rapidly but high-quality data on patient-centred outcomes and cost-effectiveness are currently lacking. Many recommendations for the treatment of iron deficiency and anaemia in national guidelines are not supported by high-quality evidence. There is a need for robust epidemiological data and well-designed clinical trials. The latter will require collaborative working between researchers and patients to design studies in ways that incorporate patients' perspectives on the research process and target outcomes that matter to them.

Serum ferritin levels in inflammation: a retrospective comparative analysis between COVID-19 and emergency surgical non-COVID-19 patients

BACKGROUND

SARS-CoV-2 infection has spread worldwide, and the pathogenic mechanism is still under investigation. The presence of a huge inflammatory response, defined as "cytokine storm," is being studied in order to understand what might be the prognostic factors implicated in the progression of the infection, with ferritin being one of such markers. The role of ferritin as a marker of inflammation is already known, and whether it changes differently between COVID and non-COVID patients still remains unclear. The aim of this retrospective analysis is to understand whether the inflammatory process in these two types is different.

METHODS

In this retrospective analysis, we compared 17 patients affected by SARS-CoV-2, who had been admitted between February and April 2020 (group A) along with 30 patients admitted for acute surgical disease with SARS-CoV-2 negative swab (group B). A further subgroup of Covid negative patients with leukocytosis was compared to group A.

RESULTS

In group A, the median (interquartile range) serum ferritin was 674 (1284) ng/mL, and it was double the cutoff (300 ng/mL) in 9 out of 17 (52%). The median (IQR) value of ferritin level in the total blood samples of group B was 231, and in the subgroup with leucocytosis, 149 (145). Group A showed a significantly higher ferritin median level compared to the entire group B (two-tailed Mann-Whitney test, p < 0.0001) as well as to the subgroup with leucocytosis (p < 0.0014).

CONCLUSIONS

The role of iron metabolism appears to be directly involved in COVID infection. On the other hand, in the acute inflammation of patients admitted for surgery, and probably in other common phlogistic processes, iron modifications appear to be self-limited. However, our finding suggests the use of ferritin as a marker for COVID infection.

Transfusion in critical care: Past, present and future

Anaemia and coagulopathy are common in critically ill patients and are associated with poor outcomes, including increased risk of mortality, myocardial infarction, failure to be liberated from mechanical ventilation and poor physical recovery. Transfusion of blood and blood products remains the corner stone of anaemia and coagulopathy treatment in critical care. However, determining when the benefits of transfusion outweigh the risks of anaemia may be challenging in some critically ill patients. Therefore, the European Society of Intensive Care Medicine prioritised the development of a clinical practice guideline to address anaemia and coagulopathy in non-bleeding critically ill patients. The aims of this article are to: (1) review the evolution of transfusion practice in critical care and the direction for future developments in this important area of transfusion medicine and (2) to provide a brief synopsis of the guideline development process and recommendations in a format designed for busy clinicians and blood bank staff. These clinical practice guidelines provide recommendations to clinicians on how best to manage non-bleeding critically ill patients at the bedside. More research is needed on alternative transfusion targets, use of transfusions in special populations (e.g., acute neurological injury, acute coronary syndromes), use of anaemia prevention strategies and point-of-care interventions to guide transfusion strategies.

Hypoferremia is Associated With Increased Hospitalization and Oxygen Demand in COVID-19 Patients

Iron metabolism might play a crucial role in cytokine release syndrome in COVID-19 patients. Therefore, we assessed iron metabolism markers in COVID-19 patients for their ability to predict disease severity. COVID-19 patients referred to the Heidelberg University Hospital were retrospectively analyzed. Patients were divided into outpatients (cohort A, n = 204), inpatients (cohort B, n = 81), and outpatients later admitted to hospital because of health deterioration (cohort C, n = 23). Iron metabolism parameters were severely altered in patients of cohort B and C compared to cohort A. In multivariate regression analysis including age, gender, CRP and iron-related parameters only serum iron and ferritin were significantly associated with hospitalization. ROC analysis revealed an AUC for serum iron of 0.894 and an iron concentration <6 μmol/l as the best cutoff-point predicting hospitalization with a sensitivity of 94.7% and a specificity of 67.9%. When stratifying inpatients in a low- and high oxygen demand group serum iron levels differed significantly between these two groups and showed a high negative correlation with the inflammatory parameters IL-6, procalcitonin, and CRP. Unexpectedly, serum iron levels poorly correlate with hepcidin. We conclude that measurement of serum iron can help predicting the severity of COVID-19. The differences in serum iron availability observed between the low and high oxygen demand group suggest that disturbed iron metabolism likely plays a causal role in the pathophysiology leading to lung injury.

Iron metabolism and lymphocyte characterisation during Covid-19 infection in ICU patients: an observational cohort study

Background

Iron metabolism and immune response to SARS-CoV-2 have not been described yet in intensive care patients, although they are likely involved in Covid-19 pathogenesis.

Methods

We performed an observational study during the peak of pandemic in our intensive care unit, dosing D-dimer, C-reactive protein, troponin T, lactate dehydrogenase, ferritin, serum iron, transferrin, transferrin saturation, transferrin soluble receptor, lymphocyte count and NK, CD3, CD4, CD8 and B subgroups of 31 patients during the first 2 weeks of their ICU stay. Correlation with mortality and severity at the time of admission was tested with the Spearman coefficient and Mann–Whitney test. Trends over time were tested with the Kruskal–Wallis analysis.

Results

Lymphopenia is severe and constant, with a nadir on day 2 of ICU stay (median 0.555 10⁹/L; interquartile range (IQR) 0.450 10⁹/L); all lymphocytic subgroups are dramatically reduced in critically ill patients, while CD4/CD8 ratio remains normal. Neither ferritin nor lymphocyte count follows significant trends in ICU patients. Transferrin saturation is extremely reduced at ICU admission (median 9%; IQR 7%), then significantly increases at days 3 to 6 (median 33%, IQR 26.5%, p value 0.026). The same trend is observed with serum iron levels (median 25.5 μg/L, IQR 69 μg/L at admission; median 73 μg/L, IQR 56 μg/L on days 3 to 6) without reaching statistical significance. Hyperferritinemia is constant during intensive care stay: however, its dosage might be helpful in individuating patients developing haemophagocytic lymphohistiocytosis. D-dimer is elevated and progressively increases from admission (median 1319 μg/L; IQR 1285 μg/L) to days 3 to 6 (median 6820 μg/L; IQR 6619 μg/L), despite not reaching significant results. We describe trends of all the abovementioned parameters during ICU stay.

Conclusions

The description of iron metabolism and lymphocyte count in Covid-19 patients admitted to the intensive care unit provided with this paper might allow a wider understanding of SARS-CoV-2 pathophysiology.

How 217 Pediatric Intensivists Manage Anemia at PICU Discharge: Online Responses to an International Survey

OBJECTIVE

To describe the management of anemia at PICU discharge by pediatric intensivists.

DESIGN

Self-administered, online, scenario-based survey.

SETTING

PICUs in Australia/New Zealand, Europe, and North America.

SUBJECTS

Pediatric intensivists.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Respondents were asked to report their decisions regarding RBC transfusions, iron, and erythropoietin prescription to children ready to be discharged from PICU, who had been admitted for hemorrhagic shock, cardiac surgery, craniofacial surgery, and polytrauma. Clinical and biological variables were altered separately in order to assess their effect on the management of anemia. Two-hundred seventeen responses were analyzed. They reported that the mean (± SEM) transfusion threshold was a hemoglobin level of 6.9 ± 0.09 g/dL after hemorrhagic shock, 7.6 ± 0.10 g/dL after cardiac surgery, 7.0 ± 0.10 g/dL after craniofacial surgery, and 7.0 ± 0.10 g/dL after polytrauma (p < 0.001). The most important increase in transfusion threshold was observed in the presence of a cyanotic heart disease (mean increase ranging from 1.80 to 2.30 g/dL when compared with baseline scenario) or left ventricular dysfunction (mean increase, 1.41-2.15 g/dL). One third of respondents stated that they would not prescribe iron at PICU discharge, regardless of the hemoglobin level or the baseline scenario. Most respondents (69.4-75.0%, depending on the scenario) did not prescribe erythropoietin.

CONCLUSIONS

Pediatric intensivists state that they use restrictive transfusion strategies at PICU discharge similar to those they use during the acute phase of critical illness. Supplemental iron is less frequently prescribed than RBCs, and prescription of erythropoietin is uncommon. Optimal management of post-PICU anemia is currently unknown. Further studies are required to highlight the consequences of this anemia and to determine appropriate management.

Peptidomic analysis of blastocyst culture medium and the effect of peptide derived from blastocyst culture medium on blastocyst formation and viability

High-quality in vitro human embryo culture medium can improve the blastocyst formation rate and blastocyst quality and be beneficial for the clinical application of single blastocyst transfer. Mammalian embryos can secrete protein products into the surrounding medium. As a group of bioactive molecules and degraded proteins, peptides have been shown to participate in various biological processes. Using liquid chromatography-tandem mass spectrometry, we performed comparative peptidomic analysis of human culture medium in blastocyst formation and nonblastocyst-formation groups. A total of 201 differentially expressed peptides originating from 157 precursor proteins were identified. Among these, a peptide derived from HERC2 (peptide derived from blastocyst culture medium [PDBCM]) passed through the zona pellucida, was distributed on the perivitelline space, was absent in arrest embryos and highly expressed in high-quality blastocysts compared with low-quality blastocysts, and significantly promoted blastocyst formation in a concentration-dependent manner. These results indicate that PDBCM may be a novel biomarker for predicting blastocyst formation and viability. The mechanism remains unclear and needs to be explored in the future.