Molecular control of iron transport

Mathematical modeling reveals ferritin as the strongest cellular driver of dietary iron transfer block in enterocytes

Intestinal mucosal block is the transient reduction in iron absorption ability of intestinal epithelial cells (enterocytes) in response to previous iron exposures that occur at the cell scale. The block characteristics have been shown to depend both on iron exposure magnitude and temporality, and understanding block control will enable deeper understanding of how intestinal iron absorption contributes to pathological iron states. Three biochemical mechanisms implicated in driving the block behavior are divalent metal transporter 1 endocytosis, ferritin iron sequestration, and iron regulatory protein regulation of iron related protein expression. In this work, a model of enterocyte iron metabolism is built based on published experimental data that is capable of reproducing the mucosal block phenomena. The model is then used to estimate the quantitative contribution of each of the three mechanisms on the properties of the mucosal block. Analysis reveals that ferritin and iron regulatory proteins are the main intracellular mechanisms contributing to the mucosal block, findings congruent with experimental predictions. Lastly, DMT1 endocytosis is shown to play a role in limiting total iron uptake by enterocytes but does not contribute to the decrease in total iron transfer across their basal membrane seen in the mucosal block.

Intravenous iron treatment fuels chronic kidney disease-induced arterial media calcification in rats

Arterial media calcification is a severe cardiovascular complication commonly manifesting in patients with chronic kidney disease (CKD). Patients with CKD frequently undergo intravenous iron therapy to address iron deficiency. Iron is suggested to be sequestered in vascular cells, potentially leading to oxidative (lipid) stress and cell death, which are recognized as key contributors to arterial calcification. The objective of this study was to investigate the effect of intravenous iron administration on CKD-induced arterial media calcification. Therefore, adenine-induced CKD rats were treated intravenously with iron and checked for arterial iron deposition and calcification, as well as for ferritin and lipid peroxidation markers. Additionally, arterial sections from patients with CKD who were dialysis dependent were analyzed for these parameters. This study showed that intravenous iron administration in CKD rats led to arterial iron deposition and a lipid peroxidation signature. CKD-induced arterial calcification was increased upon iron treatment and correlated with arterial iron accumulation and lipid peroxidation markers. Patients with CKD who were dialysis dependent showed arterial iron accumulation and elevated lipid peroxidation, but a direct correlation with arterial calcification was lacking. Taken together, iron treatment is suggested as a potential contributor to the calcification process, instead of being a predominant factor, thereby emphasizing the complexity of arterial calcification as a multifactorial disease. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Pharmacokinetics, pharmacodynamics, and tolerability of an aqueous formulation of rusfertide (PTG-300), a hepcidin mimetic, in healthy volunteers: A double-blind first-in-human study

OBJECTIVES

Rusfertide is a potent peptide mimetic of hepcidin being investigated for the treatment of polycythemia vera. This randomized, placebo-controlled, double-blind study evaluated the safety, pharmacokinetics, and pharmacodynamics of single and repeated subcutaneous doses of an aqueous formulation of rusfertide in healthy adult males.

METHODS

Subjects received single doses of 1, 3, 10, 20, 40, or 80 mg rusfertide or placebo. A separate cohort of subjects received two doses of 40 mg rusfertide or placebo 1 week apart. Blood samples for pharmacokinetics and pharmacodynamics were collected, and adverse events, clinical laboratory tests, 12-lead electrocardiograms, and vital signs were monitored.

RESULTS

Rusfertide was well tolerated. There were no serious or severe treatment-emergent adverse events, and no patterns of clinically important adverse events, or laboratory, vital sign, or electrocardiogram abnormalities. Mean maximum rusfertide plasma concentration (Cmax) and area under the concentration-time curve increased with dose, but less than dose proportionally. Median time to Cmax was 2-4.5 h for 40 and 80 mg rusfertide and 8-24 h for lower doses. Apparent clearance and half-life increased with dose. Single doses of rusfertide 1-80 mg were associated with dose-dependent decreases in serum iron and transferrin-iron saturation.

CONCLUSIONS

Rusfertide was well tolerated and showed dose-dependent pharmacokinetics and pharmacodynamics.

Preoperative anemia is a risk factor for worse 30-day outcomes in both open and endovascular repair of non-ruptured infrarenal abdominal aortic aneurysm

BACKGROUND

Anemia is a highly prevalent condition potentially linked to chronic inflammation. Preoperative anemia is an independent risk factor across many surgical fields. However, the relationship between anemia and abdominal aortic aneurysm (AAA) repair outcomes remains unclear. This study aimed to examine the effects of preoperative anemia on 30-day outcomes of non-ruptured infrarenal AAA repair.

METHODS

Patients who underwent open surgical repair (OSR) and endovascular aneurysm repair (EVAR) for infrarenal AAA were identified in National Surgical Quality Improvement Program (NSQIP) targeted databases from 2012 to 2021. Anemia was defined as preoperative hematocrit less than 39% in males and 36% in females. Multivariable logistic regression was used to compare 30-day perioperative outcomes between anemic and non-anemic patients, adjusting for demographics, comorbidities, indications, aneurysm extents, operation time, and surgical approaches.

RESULTS

There were 408 (22.13%) anemic and 1436 (77.88%) non-anemic patients who underwent OSR for non-ruptured AAA, while 3586 (25.20%) patients with and 10,644 (74.80%) without anemia underwent EVAR. In both OSR and EVAR, anemic patients had higher risks of bleeding requiring transfusion (OSR, aOR = 2.446, p < .01; EVAR, aOR = 3.691, p < .01), discharge not to home (OSR, aOR = 1.385, p = .04; EVAR, aOR = 1.27, p < .01), and 30-day readmission (OSR, aOR = 1.99, p < .01; EVAR, aOR = 1.367, p < .01). Also, anemic patients undergoing OSR had higher pulmonary events (aOR = 2.192, p < .01), sepsis (aOR = 2.352, p < .01), and venous thromboembolism (aOR = 2.913, p = .01), while in EVAR, anemic patients had higher mortality (aOR = 1.646, p = .01), cardiac complications (aOR = 1.39, p = .04), renal dysfunction (aOR = 1.658, p = .02), and unplanned reoperation (aOR = 1.322, p = .01). Moreover, in both OSR and EVAR, anemic patients had longer hospital length of stay (p < .01).

CONCLUSION

In OSR and EVAR, preoperative anemia was independently associated with worse 30-day outcomes. Preoperative anemia could be a useful marker for risk stratification for patients undergoing infrarenal AAA repair.

Social defeat stress impairs systemic iron metabolism by activating the hepcidin-ferroportin axis

Chronic psychological stress has been reported to decrease circulating iron concentrations and impair hematopoiesis. However, the underlying mechanisms remain unclear. This study aimed to investigate the effects of psychological stress on biological iron metabolism by using the social defeat stress (SDS) model, a widely used model of depression. Compared with control mice, mice subjected to SDS (SDS mice) had lower social interaction (SI) behavior. The SDS mice also showed impaired hematopoiesis, as evidenced by reduced circulating red blood cell counts, elevated reticulocyte counts, and decreased plasma iron levels. In the SDS mice, the iron contents in the bone marrow decreased, whereas those in the spleen increased, suggesting dysregulation in systemic iron metabolism. The concentrations of plasma hepcidin, an important regulator of systemic iron homeostasis, increased in the SDS mice. Meanwhile, the concentrations of ferroportin, an iron transport protein negatively regulated by hepcidin, were lower in the spleen and duodenum of the SDS mice than in those of the control mice. Treatment with dalteparin, a hepcidin inhibitor, prevented the decrease in plasma iron levels in the SDS mice. The gene expression and enzyme activity of furin, which converts the precursor hepcidin to active hepcidin, were high and positively correlated with plasma hepcidin concentration. Thus, furin activation might be responsible for the increased plasma hepcidin concentration. This study is the first to show that psychological stress disrupts systemic iron homeostasis by activating the hepcidin-ferroportin axis. Consideration of psychological stressors might be beneficial in the treatment of diseases with iron-refractory anemia.

Evaluation of Nutrition and Performance Parameters in Division 1 Collegiate Athletes

BACKGROUND

Testing and evaluating athletes is necessary and should include performance, body composition, and nutrition. The purpose of this study was to report assessments of dietary intake, V˙O2max, and body composition in D1 collegiate athletes and examine relationships between these assessments.

METHODS

Dietary intake was assessed with 3-day recalls and compared to recommendations, and body composition was assessed via bioelectrical impedance analysis (BIA) (n = 48). V˙O2max was evaluated using a graded exercise test (GXT) with a verification bout (n = 35). Reliability between "true" V˙O2max and verification was determined. Correlations and regressions were performed.

RESULTS

Energy, carbohydrate, and micronutrient intake was lower than recommendations. Mean V˙O2max was 47.3 and 47.4 mL·kg-1·min-1 for GXT and verification, respectively. While correlations were apparent among dietary intake, V˙O2max, and body composition, percent fat-free mass (%FFM) predicted 36% of V˙O2max.

CONCLUSIONS

Collegiate athletes are not meeting energy and carbohydrate recommendations and exceed fat recommendations. Vitamin D and magnesium were low in all sports, and iron and calcium were low in females. V˙O2max ranged from 35.6 to 63.0 mL·kg-1·min-1, with females below average and males meeting typical values for their designated sport. Assessing D1 athletes can provide guidance for sports dietitians, coaches, and strength and conditioning specialists to track and monitor nutrition in athletes.

Phenotypic Alterations in Erythroid Nucleated Cells of Spleen and Bone Marrow in Acute Hypoxia

Hypoxia leads to metabolic changes at the cellular, tissue, and organismal levels. The molecular mechanisms for controlling physiological changes during hypoxia have not yet been fully studied. Erythroid cells are essential for adjusting the rate of erythropoiesis and can influence the development and differentiation of immune cells under normal and pathological conditions. We simulated high-altitude hypoxia conditions for mice and assessed the content of erythroid nucleated cells in the spleen and bone marrow under the existing microenvironment. For a pure population of CD71+ erythroid cells, we assessed the production of cytokines and the expression of genes that regulate the immune response. Our findings show changes in the cellular composition of the bone marrow and spleen during hypoxia, as well as changes in the composition of the erythroid cell subpopulations during acute hypoxic exposure in the form of a decrease in orthochromatophilic erythroid cells that are ready for rapid enucleation and the accumulation of their precursors. Cytokine production normally differs only between organs; this effect persists during hypoxia. In the bone marrow, during hypoxia, genes of the C-lectin pathway are activated. Thus, hypoxia triggers the activation of various adaptive and compensatory mechanisms in order to limit inflammatory processes and modify metabolism.

Hepcidin across pregnancy and its correlation with maternal markers of iron and inflammation, maternal body weight outcomes, and offspring neurodevelopmental outcomes: a systematic review and meta-analysis

OBJECTIVE

This study evaluated the correlation between maternal hepcidin and other biomarkers of iron status, markers of inflammation, and maternal body weight during pregnancy, as well as neurodevelopment in the offspring.

DATA SOURCES

PubMed, Web of Science, Scopus, and Embase were searched from inception until March 2022.

STUDY ELIGIBILITY CRITERIA

Studies conducted among pregnant women without apparent pregnancy complications were included. Eligible studies reported correlation coefficients between maternal hepcidin and any outcomes of maternal biomarkers of iron status or inflammatory load during pregnancy, prenatal maternal body weight, and offspring neurodevelopment. Studies without correlation data were eligible if they quantitatively reported volumes of both maternal hepcidin and any marker of iron status and/or inflammatory load during gestation.

METHODS

Pooled correlation coefficients between maternal hepcidin and outcomes of interest were calculated using the Fisher r-to-Z transformation. Both fixed-effects and DerSimonian and Laird random-effects models were used to calculate pooled correlation coefficient. When meta-analysis was not feasible, results were descriptively synthesized.

RESULTS

Forty-six studies with 6624 participants were eligible. Hepcidin was significantly correlated with hemoglobin in the third trimester (r=0.21; 95% confidence interval, 0.1-0.32); ferritin in the first (r=0.31; 95% confidence interval, 0.01-0.61) and third trimester (r=0.35; 95% confidence interval, 0.23-0.48); soluble transferrin receptor in the second trimester (r=-0.27; 95% confidence interval, -0.4 to -0.14); total iron-binding capacity in the second trimester (r=0.37; 95% confidence interval, 0.24-0.50); and serum iron in the third trimester (r=0.11; 95% confidence interval, 0.02-0.19). Hepcidin was significantly correlated with the inflammatory marker interleukin-6 in the third trimester (r=0.26; 95% confidence interval, 0.17-0.34) and C-reactive protein in the second (r=0.16; 95% confidence interval, 0.03-0.30) and third trimester (r=0.28; 95% confidence interval, 0.04-0.52). Four out of 5 studies reported weak-to-moderate positive correlation between hepcidin and body mass index. Hepcidin levels varied across body mass index categories. No single study reported the relationship between maternal hepcidin and neurodevelopment in offspring.

CONCLUSION

Hepcidin weakly to moderately correlates with biomarkers of iron and inflammation in pregnancy.

Iron-Deficiency Anemia in CKD: A Narrative Review for the Kidney Care Team

Anemia is a common complication of chronic kidney disease (CKD) and is associated with increased mortality and reduced health-related quality of life. Anemia is characterized by a decrease in hemoglobin, the iron-rich protein that the body uses for oxygen transport. Iron is required to produce hemoglobin, and disruptions in the iron homeostasis can lead to iron-deficiency anemia. Management of anemia in individuals with CKD is typically performed by a team of physicians, nurse practitioners, physician assistants, or registered nurses. Throughout the care continuum, the management can be enhanced by multidisciplinary care, and individuals with CKD can benefit from the involvement of other specialties, with dietitians/nutritionists playing an important role. However, a key area of unmet clinical need is how to assess and address iron-deficiency anemia. This review aims to provide an overview of iron-deficiency anemia in CKD and how this may be diagnosed and managed by the entire kidney care team, such as describing the mechanisms underlying iron homeostasis, the complications of iron-deficiency anemia, and the current challenges associated with its diagnosis and treatment in CKD. Opportunities for each multidisciplinary team member to add value to the care of individuals with CKD and iron-deficiency anemia are also described.

Attenuation of ferroptosis as a potential therapeutic target for neuropsychiatric manifestations of post-COVID syndrome

Coronavirus disease-19 (COVID-19), caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), is associated with the persistence of pre-existing or the emergence of new neurological and psychiatric manifestations as a part of a multi-system affection known collectively as "post-COVID syndrome." Cognitive decline is the most prominent feature among these manifestations. The underlying neurobiological mechanisms remain under intense investigation. Ferroptosis is a form of cell death that results from the excessive accumulation of intracellular reactive iron, which mediates lipid peroxidation. The accumulation of lipid-based reactive oxygen species (ROS) and the impairment of glutathione peroxidase 4 (GPX4) activity trigger ferroptosis. The COVID-19-associated cytokine storm enhances the levels of circulating pro-inflammatory cytokines and causes immune-cell hyper-activation that is tightly linked to iron dysregulation. Severe COVID-19 presents with iron overload as one of the main features of its pathogenesis. Iron overload promotes a state of inflammation and immune dysfunction. This is well demonstrated by the strong association between COVID-19 severity and high levels of ferritin, which is a well-known inflammatory and iron overload biomarker. The dysregulation of iron, the high levels of lipid peroxidation biomarkers, and the inactivation of GPX4 in COVID-19 patients make a strong case for ferroptosis as a potential mechanism behind post-COVID neuropsychiatric deficits. Therefore, here we review the characteristics of iron and the attenuation of ferroptosis as a potential therapeutic target for neuropsychiatric post-COVID syndrome.

Effects of hypoxia-inducible factor prolyl hydroxylase inhibitors versus erythropoiesis-stimulating agents on iron metabolism and inflammation in patients undergoing dialysis: A systematic review and meta-analysis

Aims

This study aimed to evaluate the effects of hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) on iron metabolism and inflammation in dialysis-dependent chronic kidney disease (DD-CKD) patients.

Methods

PubMed, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov websites were searched for randomized controlled trials (RCTs) investigating HIF-PHIs versus ESAs for DD-CKD patients.

Key findings

Twenty studies with 14,737 participants were included in the meta-analysis, which demonstrated no significant difference in the effect of transferrin saturation and ferritin between HIF-PHIs and the ESAs group (MD, 0.65; 95%CI, -0.45 to 1.75; very low certainty; SMD, -0.03; 95% CI, -0.13 to 0.07; low certainty). However, HIF-PHIs significantly increased the iron (MD, 2.30; 95% CI, 1.40 to 3.20; low certainty), total iron-binding capacity (SMD, 0.82; 95% CI, 0.66 to 0.98; low certainty), and transferrin (SMD, 0.90; 95%CI, 0.74 to 1.05; moderate certainty) levels when compared with the ESAs group. In contrast, the hepcidin level and dosage of intravenous iron were significantly decreased in the HIF-PHIs group compared with the ESAs group (MD, -15.06, 95%CI, -21.96 to -8.16; low certainty; MD, -18.07; 95% CI, -30.05 to -6.09; low certainty). The maintenance dose requirements of roxadustat were independent of baseline CRP or hsCRP levels with respect to the effect on inflammation.

Significance

HIF-PHIs promote iron utilization and reduce the use of intravenous iron therapy. Furthermore, HIF-PHIs, such as roxadustat, maintain the erythropoietic response independent of the inflammatory state. Thus, HIF-PHIs may be an alternative treatment strategy for anemia in DD-CKD patients, where ESA is hyporesponsive due to iron deficiency and inflammation.

Tip60/Kat5 may be a novel candidate histone acetyltransferase for the regulation of liver iron localization via acetylation

Hepcidin (HAMP), an iron regulatory hormone synthesized by liver hepatocytes, works together with ferritin (FTH) and ferroportin (FPN) in regulating the storage, transport, and utilization of iron in the cell. Epigenetic mechanisms, especially acetylation, also play an important role in the regulation of iron metabolism. However, a target protein has not been mentioned yet. With this preliminary study, we investigated the effect of histone acetyltransferase TIP60 on the expression of HAMP, FTH, and FPN. In addition, how the depletion of Tip60, which regulates the circadian system, affects the daily expression of Hamp was examined at six Zeitgeber time (ZT) points. For this purpose, liver-specific Tip60 knockout mice (mutant) were produced with tamoxifen-inducible Cre/lox recombination and an iron overload model in mice was generated. While HAMP and FTH expressions decreased, FPN expression increased in the mutant group. Interestingly, there was no change in the iron content. A significant increase was observed in the expressions of HAMP, FTH, and FPN and total liver iron content in the liver tissue of the iron overload group. Since intracellular iron concentration is involved in regulating the circadian clock, temporal expression of Hamp was investigated in control and mutant groups at six ZT points. In the control group, Hamp accumulated in a circadian manner with maximal and minimal levels reaching around ZT16 and ZT8, respectively. In the mutant group, there was a significant reduction in Hamp expression in the light phase ZT0 and ZT4 and in the dark phase ZT16. These data are the first findings demonstrating a possible relationship between Tip60 and iron metabolism.

Cytochrome P450 1B1: A Key Regulator of Ocular Iron Homeostasis and Oxidative Stress

Cytochrome P450 (CYP) 1B1 belongs to the superfamily of heme-containing monooxygenases. Unlike other CYP enzymes, which are highly expressed in the liver, CYP1B1 is predominantly found in extrahepatic tissues, such as the brain, and ocular tissues including retina and trabecular meshwork. CYP1B1 metabolizes exogenous chemicals such as polycyclic aromatic hydrocarbons. CYP1B1 also metabolizes endogenous bioactive compounds including estradiol and arachidonic acid. These metabolites impact various cellular and physiological processes during development and pathological processes. We previously showed that CYP1B1 deficiency mitigates ischemia-mediated retinal neovascularization and drives the trabecular meshwork dysgenesis through increased levels of oxidative stress. However, the underlying mechanisms responsible for CYP1B1-deficiency-mediated increased oxidative stress remain largely unresolved. Iron is an essential element and utilized as a cofactor in a variety of enzymes. However, excess iron promotes the production of hydroxyl radicals, lipid peroxidation, increased oxidative stress, and cell damage. The retinal endothelium is recognized as a major component of the blood-retinal barrier, which controls ocular iron levels through the modulation of proteins involved in iron regulation present in retinal endothelial cells, as well as other ocular cell types including trabecular meshwork cells. We previously showed increased levels of reactive oxygen species and lipid peroxidation in the absence of CYP1B1, and in the retinal vasculature and trabecular meshwork, which was reversed by administration of antioxidant N-acetylcysteine. Here, we review the important role CYP1B1 expression and activity play in maintaining retinal redox homeostasis through the modulation of iron levels by retinal endothelial cells. The relationship between CYP1B1 expression and activity and iron levels has not been previously delineated. We review the potential significance of CYP1B1 expression, estrogen metabolism, and hepcidin-ferroportin regulatory axis in the local regulation of ocular iron levels.

Serum Vitamin D Concentrations, Time to Pregnancy, and Pregnancy Outcomes among Preconception Couples: A Cohort Study in Shanghai, China

BACKGROUND

The role of vitamin D in reproductive health is still unclear. This study aimed to assess the effect of serum 25-hydroxyvitamin D (25(OH)D), among preconception couples, on fecundity, and the associations between 25(OH)D concentrations before and during pregnancy, and pregnancy outcomes.

METHODS

200 preconception couples attempting to conceive were recruited and were followed-up until childbirth. Time to pregnancy was collected via telephone every two months or obtained via a questionnaire during pregnancy. Blood samples were collected to measure serum 25(OH)D levels from both partners at enrollment and from women during the second and third trimester of pregnancy.

RESULTS

Couples had higher conception rates within six months (adjusted odds ratio (aOR): 3.72, 95% CI: 1.16, 11.9) and reduced time to pregnancy (adjusted fecundability ratio (aFR): 1.50, 95% CI: 1.01, 2.23) if male partners had sufficient 25(OH)D compared with insufficient 25(OH)D. Compared to pregnant women with insufficient 25(OH)D in the third trimester of pregnancy, sufficient 25(OH)D was associated with reduced odds of anemia (OR: 0.22, 95% CI: 0.06, 0.82), longer gestational age (β: 0.53, 95% CI: 0.04, 1.01) and newborns' higher ponderal index (β: 0.10, 95% CI: 0.01, 0.19).

CONCLUSIONS

Sufficient serum 25(OH)D levels among preconception men or during pregnancy were associated with better reproductive health.

The beneficial role of Hepcidin peptide inhibitor in improved the symptoms of COVID-19 in diabetics: anti-inflammatory and potential therapeutic effects

Coronavirus Disease 2019 (COVID-19) is a recent public health issue worldwide. Also, diabetes is a frequent condition with high mortality. There is a strong relationship between COVID-19 and diabetes. This article analyses the intricate relationship between COVID-19 and hepcidin. Hepcidin increases in aged non-insulin diabetic patients. Hepcidin is the last target treatment of several medications commonly used. Viral diseases, especially SARS-CoV19, can activate the hepcidin pathway leading to an elevation in the iron load. This increased iron is released into the bloodstream and results in cell death through ferroptosis, like free iron. Excess iron has pro-coagulative and toxic effects. Hepcidin overexpression and iron overload are associated with COVID-19 infection and can be considered potential targets for treatment. Several studies have shown dalteparin (anti-Hepcidin) could improve the symptoms of COVID-19 in diabetics by appropriately modulating and decreasing oxidative stress and inflammation. This finding can be leading to enhancing the existing knowledge about Therapeutic measures for reducing Covid-19 impairments in diabetics and is suggested as a possible therapeutic agent in diabetes.

Influences of Vitamin D and Iron Status on Skeletal Muscle Health: A Narrative Review

There is conflicting evidence of the roles vitamin D and iron have in isolation and combined in relation to muscle health. The purpose of this narrative review was to examine the current literature on the roles that vitamin D and iron have on skeletal muscle mass, strength, and function and how these nutrients are associated with skeletal muscle health in specific populations. Secondary purposes include exploring if low vitamin D and iron status are interrelated with skeletal muscle health and chronic inflammation and reviewing the influence of animal-source foods rich in these nutrients on health and performance. PubMed, Scopus, SPORT Discus, EMBAE, MEDLINE, and Google Scholar databases were searched to determine eligible studies. There was a positive effect of vitamin D on muscle mass, particularly in older adults. There was a positive effect of iron on aerobic and anaerobic performance. Studies reported mixed results for both vitamin D and iron on muscle strength and function. While vitamin D and iron deficiency commonly occur in combination, few studies examined effects on skeletal muscle health and inflammation. Isolated nutrients such as iron and vitamin D may have positive outcomes; however, nutrients within food sources may be most effective in improving skeletal muscle health.

Nutritional Status in Chinese Patients with Obesity Following Sleeve Gastrectomy/Roux-en-Y Gastric Bypass: A Retrospective Multicenter Cohort Study

Metabolic surgery (MS) is one of the most effective therapies for treating obesity. Due to the lack of multicenter cohort research on nutritional evaluations after surgery in Chinese patients, we explored the changes in nutritional status following MS in Chinese patients. This was a retrospective study of patients (n = 903) who underwent sleeve gastrectomy (SG) (n = 640) or Roux-en-Y gastric bypass (RYGB) (n = 263) for obesity at five different hospitals in China between 17 February 2011, and 20 December 2019. Major nutrients were evaluated at baseline and 1, 3, 6, and 12 months postoperatively. Hb levels decreased, and anemia prevalence increased at 12 months after MS in the premenopausal female group. Moreover, patients with preoperative anemia had an increased risk of postoperative anemia. The ferritin levels (p < 0.001) decreased and iron deficiency increased (p < 0.001) at 12 months after MS among premenopausal females. No significant changes in folate deficiency and vitamin B12 deficiency were found throughout the study. The bone mineral density (BMD) of the femoral neck, lumbar spine, and total hip significantly decreased from baseline to 12 months after MS; however, no new patients developed osteopenia or osteoporosis after MS. Based on 12 months of follow-up, premenopausal females presented a high incidence of anemia after MS. Although we found no differences in osteopenia and osteoporosis prevalence after MS, the BMD did decrease significantly, which suggests that nutrient supplements and long-term follow-up are especially necessary postoperation.

HIV-1 infection in sickle cell disease and sickle cell trait: role of iron and innate response

INTRODUCTION

Sickle cell disease (SCD), an inherited hemoglobinopathy, affects primarily African Americans in the U.S.A. In addition, about 15% African Americans carry sickle cell trait (SCT). Despite the risk associated with blood transfusions, SCD patients have lower risk of acquiring HIV-1 infection. SCT individuals might also have some protection from HIV-1 infection.

AREAS COVERED

Here, we will review recent and previous studies with the focus on molecular mechanisms that might underlie and contribute to the protection of individuals with SCD and SCT from HIV-1 infection. As both of these conditions predispose to hemolysis, we will focus our discussion on the effects of systemic and intracellular iron on HIV-1 infection and progression. We will also review changes in iron metabolism and activation of innate antiviral responses in SCD and SCT and their effects on HIV-1 infection.

EXPERT OPINION

Previous studies, including ours, showed that SCD might protect from HIV-1 infection. This protection is likely due to the upregulation of complex protein network in response to hemolysis, hypoxia and interferon signaling. These findings are important not only for HIV-1 field but also for SCD cure efforts as antiviral state of SCD patients may adversely affect lentivirus-based gene therapy efforts.

A farewell to phlebotomy-use of placenta-derived drugs Laennec and Porcine for improving hereditary hemochromatosis without phlebotomy: a case report

BACKGROUND

Human hepcidin, produced by hepatocytes, regulates intestinal iron absorption, iron recycling by macrophages, and iron release from hepatic storage. Recent studies indicate that hepcidin deficiency is the underlying cause of the most known form of hereditary hemochromatosis.

CASE PRESENTATION

A 44-year-old Asian man who developed type 2 diabetes mellitus had elevated serum ferritin levels (10,191 ng/mL). Liver biopsy revealed remarkable iron deposition in the hepatocytes and relatively advanced fibrosis (F3). Chromosomal analysis confirmed the presence of transferrin receptor type 2 mutations (c.1100T>G, c.2008_9delAC, hereditary hemochromatosis type 3 analyzed by Kawabata). The patient received intravenous infusions of Laennec (672 mg/day, three times/week) or oral administration with Porcine (3.87 g/day) for 84 months as an alternative to repeated phlebotomy. At the end of the treatment period, serum ferritin level decreased to 428.4 ng/mL (below the baseline level of 536.8 ng/mL). Hemoglobin A1c levels also improved after treatment with the same or lower dose of insulin (8.8% before versus 6.8% after). Plural liver biopsies revealed remarkable improvements in the grade of iron deposition and fibrosis (F3 before versus F1 after) of the liver tissue.

CONCLUSION

The discovery of hepcidin and its role in iron metabolism could lead to novel therapies for hereditary hemochromatosis. Laennec (parenteral) and Porcine (oral), which act as hepcidin inducers, actually improved iron overload in this hereditary hemochromatosis patient, without utilizing sequential phlebotomy. This suggests the possibility of not only improving the prognosis of hereditary hemochromatosis (types 1, 2, and 3) but also ameliorating complications, such as type 2 diabetes, liver fibrosis, and hypogonadism. Laennec and Porcine can completely replace continuous venesection in patients with venesection and may improve other iron-overloading disorders caused by hepcidin deficiency.

Hepcidin induces intestinal calcium uptake while suppressing iron uptake in Caco-2 cells

Abnormal calcium absorption and iron overload from iron hyperabsorption can contribute to osteoporosis as found in several diseases, including hemochromatosis and thalassemia. Previous studies in thalassemic mice showed the positive effects of the iron uptake suppressor, hepcidin, on calcium transport. However, whether this effect could be replicated in other conditions is not known. Therefore, this study aimed to investigate the effects of hepcidin on iron and calcium uptake ability under physiological, iron uptake stimulation and calcium uptake suppression. To investigate the potential mechanism, effects of hepcidin on the expression of iron and calcium transporter and transport-associated protein in Caco-2 cells were also determined. Our results showed that intestinal cell iron uptake was significantly increased by ascorbic acid together with ferric ammonium citrate (FAC), but this phenomenon was suppressed by hepcidin. Interestingly, hepcidin significantly increased calcium uptake under physiological condition but not under iron uptake stimulation. While hepcidin significantly suppressed the expression of iron transporter, it had no effect on calcium transporter expression. This indicated that hepcidin-induced intestinal cell calcium uptake did not occur through the stimulation of calcium transporter expression. On the other hand, 1,25(OH)₂D₃ effectively induced intestinal cell calcium uptake, but it did not affect intestinal cell iron uptake or iron transporter expression. The 1,25(OH)₂D₃-induced intestinal cell calcium uptake was abolished by 12 mM CaCl₂; however, hepcidin could not rescue intestinal cell calcium uptake suppression by CaCl₂. Taken together, our results showed that hepcidin could effectively and concurrently induce intestinal cell calcium uptake while reducing intestinal cell iron uptake under physiological and iron uptake stimulation conditions, suggesting its therapeutic potential for inactive calcium absorption, particularly in thalassemic patients or patients who did not adequately respond to 1,25(OH)₂D₃.

Antiviral peptides from aquatic organisms: Functionality and potential inhibitory effect on SARS-CoV-2

Several antiviral peptides (AVPs) from aquatic organisms have been effective in interfering with the actions of infectious viruses, such as Human Immunodeficiency Virus-1 and Herpes Simplex Virus-1 and 2. AVPs are able to block viral attachment or entry into host cells, inhibit internal fusion or replication events by suppressing viral gene transcription, and prevent viral infections by modulating host immunity. Therefore, as promising therapeutics, the potential of aquatic AVPs for use against the COVID-19 pandemic caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is considered. At present no therapeutic drugs are yet available. A total of 32 AVPs derived from fish and shellfish species are discussed in this review paper with notes on their properties and mechanisms of action in the inhibition of viral diseases both in humans and animals, emphasizing on SARS-CoV-2. The molecular structure of novel SARS-CoV-2 with its entry mechanisms, clinical signs and symptoms are also discussed. In spite of only a few study of these AVPs against SARS-CoV-2, aquatic AVPs properties and infection pathways (entry, replication and particle release) into coronaviruses are linked in this paper to postulate an analysis of their potential but unconfirmed actions to impair SARS-CoV-2 infection in humans.

Hypoxia-Inducible Factor Stabilization as an Emerging Therapy for CKD-Related Anemia: Report From a Scientific Workshop Sponsored by the National Kidney Foundation

The National Kidney Foundation convened an interdisciplinary international workshop in March 2019 to discuss the potential role of a new class of agents for the treatment of anemia in patients with chronic kidney disease (CKD): the hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs). International experts with expertise in physiology, biochemistry, structural chemistry, translational medicine and clinical management of anemia participated. Participants reviewed the unmet needs of current anemia treatment, the biology of hypoxia-inducible factor, the pharmacology of prolyl hydroxylase inhibitors, and the results of phase 2 clinical trials of HIF-PHIs among patients with both non-dialysis dependent and dialysis-dependent CKD. The results of key phase 3 clinical trials of HIF-PHIs in the public domain as of this writing are also presented in this article although they appeared after the workshop was completed. Participants in the workshop developed a number of recommendations for further examination of HIF-PHIs which are summarized in this article and include long-term safety issues, potential benefits, and practical considerations for implementation including patient and provider education.

In Terms of Nutrition, the Most Suitable Method for Bariatric Surgery: Laparoscopic Sleeve Gastrectomy or Roux-en-Y Gastric Bypass? A Systematic Review and Meta-analysis

This study assesses the differences in postoperative nutritional status between laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB). We searched the literature from PubMed, Web of Science, Embase, and the Cochrane Library database. Twenty-nine articles were included, with a total of 5437 obese patients. After bariatric surgery, the LSG group had less anemia and iron deficiency anemia than the LRYGB group. The serum iron, ferritin deficiency, and vitamin B₁₂ rates after LSG were lower than patients receiving LRYGB. And PTH and serum phosphorus concentration of patients after LSG were both lower than those after LRYGB. The postoperative results of LSG were better than that of LRYGB. Therefore, we recommend LSG for a better postoperative nutrition, but only for reference.

Chimeric Protein IPath® with Chelating Activity Improves Atlantic Salmon's Immunity against Infectious Diseases

Infection processes displayed by pathogens require the acquisition of essential inorganic nutrients and trace elements from the host to survive and proliferate. Without a doubt, iron is a crucial trace metal for all living organisms and also a pivotal component in the host–parasite interactions. In particular, the host reduces the iron available to face the infectious disease, increasing iron transport proteins’ expression and activating the heme synthesis and degradation pathways. Moreover, recent findings have suggested that iron metabolism modulation in fish promotes the immune response by reducing cellular iron toxicity. We hypothesized that recombinant proteins related to iron metabolism could modulate the fish’s immune system through iron metabolism and iron-responsive genes. Here a chimeric iron transport protein (IPath^®) was bioinformatically designed and then expressed in a recombinant bacterial system. The IPath^® protein showed a significant chelating activity under in vitro conditions and biological activity. Taking this evidence, a vaccine candidate based on IPath^® was evaluated in Atlantic salmon challenged with three different fish pathogens. Experimental trials were conducted using two fish groups: one immunized with IPath^® and another injected with adjutant as the control group. After 400 accumulated thermal units (ATUs), two different infection trials were performed. In the first one, fish were infected with the bacterium Aeromonas salmonicida, and in a second trial, fish were exposed to the ectoparasite Caligus rogercresseyi and subsequently infected with the intracellular bacterium Piscirickettsia salmonis. Fish immunized with IPath^® showed a significant delay in the mortality curve in response to A. salmonicida and P. salmonis infections. However, no significant differences between infected and control fish groups were observed at the end of the experiment. Notably, sea lice burden reduction was observed in vaccinated Atlantic salmon. Transcriptional analysis evidenced a high modulation of iron-homeostasis-related genes in fish vaccinated with IPath^® compared to the control group during the infection. Moreover, increasing expression of Atlantic salmon IgT was associated with IPath^® immunization. This study provides evidence that the IPath^® protein could be used as an antigen or booster in commercial fish vaccines, improving the immune response against relevant pathogens for salmon aquaculture.

Microcytic and Malarial Anaemia Prevalence in Urban Children ≤15 Years in the Mount Cameroon Area: A Cross-Sectional Study on Risk Factors

BACKGROUND

Anaemia, a common nutritional deficiency, is a public health problem in the Mount Cameroon area. This study determined the prevalence and possible risk factors of microcytic and malarial anaemia in children less than ≤15 years residing in the Buea and Limbe municipalities in the Mount Cameroon area.

METHODS

A total of 566 children were clinically examined in a cross-sectional study from December 2018 to August 2019 for anaemia and malaria parasites. Blood samples collected were used in evaluating full blood count with the aid of an automated haemoanalyser, and malaria parasite was confirmed by microscopy. Anaemia was defined based on WHO standards while microcytic anaemia and malarial anaemia were defined as microcytosis + anaemia and malaria + anaemia, respectively. Factors that showed significance in the bivariate analysis were entered into a multinomial logistic regression to determine risk factors for microcytic and malarial anaemia.

RESULTS

The overall prevalence for anaemia, microcytosis, microcytic anaemia, and malarial anaemia was, respectively, 68.7%, 48.9%, 36.9%, and 19.6% with microcytic anaemia representing 53.7% of all anaemic cases. Risk factors for microcytic anaemia included child age of 1-5 years (P=0.007), forest ethnicity (P=0.019), parents being farmers (P=0.038) or jobless (P=0.009), and having moderate malaria parasitaemia (P=0.048) while those for malarial anaemia were child age of 6-10 years (P=0.008), parents' age of 26-35 years (P=0.049), parents being jobless (P=0.023), and consuming plantains 3-4 times (P=0.024) a week.

CONCLUSION

Microcytic anaemia is getting to be a severe public health concern while malarial anaemia is a mild public health issue in children residing in urban areas of Mount Cameroon. Parents' occupation was directly linked to all anaemia forms; hence, any intervention to curb anaemia should consider aspects that will raise the socioeconomic status of the population.

Investigating Dual-Energy CT Post-Contrast Phases for Liver Iron Quantification: A Preliminary Study

BACKGROUND AND PURPOSE

Quantification of hepatic virtual iron content (VIC) by using Multidetector Dual Energy Computed Tomography (DECT) has been recently investigated since this technique could offer a good compromise between accuracy and non-invasiveness for liver iron content quantification. The aim of our study is to investigate differences in VIC at different DECT time points (namely baseline and arterial, venous and tardive phases), identifying the most reliable and also exploring the underlying temporal trend of these values.

MATERIALS AND METHODS

Eleven patients who underwent DECT examination and were characterized by low liver fat content were included in this retrospective study. By using the Syngo.via Frontier-DE IronVNC tool, regions of interest (ROI) were placed on the VIC images at 3 hepatic levels, both in left and right liver lobes, at each DECT time point. Friedman's test followed by Bonferroni-adjusted Wilcoxon signed-rank test for post-hoc analysis was performed to assess differences between DECT timepoints. Page's L test was performed to test the temporal trend of VIC across the 4 examined timepoints.

RESULTS

For both liver lobes, Friedman's test followed by Bonferroni-adjusted Wilcoxon signed-rank test revealed that VIC values differed significantly when extracted from ROIs placed at the 4 different timepoints. The Page's L test for multiple comparison revealed a significant growing trend for VIC, from baseline acquisition to the fourth and last time point post-contrast agent injection.

CONCLUSIONS

The extraction of hepatic VIC in healthy subjects was found to be significantly influenced by the DECT time point chosen for the extrapolation of the VIC values.

Anaemia and Related Nutritional Deficiencies in Chinese Patients with Obesity, 12 Months Following Laparoscopic Sleeve Gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) has become a predominant bariatric procedure at present. However, data are scarce regarding the nutritional impact of this procedure on Chinese patients. This study aimed to evaluate the prevalence of nutritional deficiency after LSG in Chinese patients.

METHODS

Eighty-two patients with obesity were recruited from the Second Xiangya Hospital of Central South University, and all patients underwent LSG and completed the visit.

RESULTS

Compared with the baseline, the serum albumin levels increased significantly at 1-12 months (P<0.001) after surgery, and the hypoalbuminemia rate decreased from 8.5% to 0% throughout the study (P=0.063). Anaemia was present in 7.3% of all patients before surgery, and its prevalence increased to 11.0% at 12 months post-operation (P=0.109). The anaemia rate of fertile females was higher than that of males (21.4% vs 2.3%, P=0.036). No significant changes were found in vitamin B12 deficiency throughout the study (0% vs 3.8%, P=1.0). The increases in the folate deficiency were only discovered in the female group (3.7% vs 20%, P=0.031) and the obese without type 2 diabetes (T2D) group after LSG (27.3% vs 47.1%, P=0.031). A decrease in the ferritin levels and an increase in iron deficiency at 12 months post-surgery were found among all patients.

CONCLUSION

Based on 12 months of follow-up, LSG is effective in controlling metabolic syndrome and has a modest effect on nutritional deficiencies, which suggests that LSG is an effective and comparably safe procedure for Chinese patients considering nutritional deficiencies at 12 months post-surgery.

Comparison of the effects of zinc oxide and zinc oxide nanoparticles on the expression of hepcidin gene in rat liver

OBJECTIVES

Nanoparticles have special properties, such as increased intestinal absorption, permeability, and so on. Zinc oxide (ZnO) nanoparticles have medical applications such as using in drug production. Studies of ZnO nanoparticles have shown the role of these particles in reducing or increasing the genes expression. Given the important role of hepcidin in the development of anemia and iron overload diseases, this study investigated the effect of ZnO nanoparticles on the hepatic expression of the hepcidin gene to help find a way to treat these diseases.

METHODS

In this experimental study, 24 male Westar rats were divided into three groups: control, ZnO treating group and ZnO nanoparticle treating group. Both ZnO and ZnO nanoparticles were injected with 50 mg/kg body weight for 14 days. At the end, serums were collected and iron, ferritin and IL-6 levels were measured. Expression of the hepcidin gene was done by Real Time PCR.

RESULTS

ZnO and the ZnO nanoparticle significantly increased the expression of the hepcidin gene relative to the control group. The increase in expression of the hepcidin gene in ZnO nanoparticles was more significant than in the ZnO.

CONCLUSION

ZnO nanoparticles led to significant increase in expression of the hepcidin gene.

Effects of hypoxia-inducible factor prolyl hydroxylase inhibitors on iron regulation in non-dialysis-dependent chronic kidney disease patients with anemia: A systematic review and meta-analysis

Phase 2 and phase 3 clinical studies showed that hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) efficiently increased hemoglobin levels in both dialysis-dependent and non-dialysis-dependent chronic kidney disease (CKD) patients. However, the effects of HIF-PHIs on iron regulation have not been consistent among clinical trials. We performed a systematic review and meta-analysis of randomized controlled trials to evaluate the effects of six HIF-PHIs on iron regulation in non-dialysis CKD patients. Electronic databases were searched from inception to April 20, 2020, for eligible studies. Changes from baseline in transferrin saturation (TSAT), total iron-binding capacity (TIBC), iron, ferritin, and hepcidin levels were pooled using the inverse-variance method and presented as the mean difference (MD) or standardized MD (SMD) with 95 % confidence intervals (CIs). Meta-analysis of the included studies showed that, in non-dialysis-dependent CKD patients, HIF-PHIs decreased TSAT (MD, -4.51; 95 % CI, -5.81 to -3.21), ferritin (MD, -47.29; 95 % CI, -54.59 to -40.00) and hepcidin (SMD, -0.94; 95 % CI, -1.25 to -0.62), increased TIBC (MD, 9.15; 95 % CI, 7.08-11.22), and did not affect serum iron (MD, -0.31; 95 % CI, -2.05 to 1.42) despite enhanced erythropoiesis. This systematic review suggests that HIF-PHIs promote iron utilization in non-dialysis-dependent CKD patients. Importantly, HIF-PHIs are associated with increased transferrin levels (and TIBC), leading to reduced TSAT. Therefore, the reduction of TSAT after HIF-PHIs should not be interpreted as iron deficiency.

Hepcidin and GDF-15 are potential biomarkers of iron deficiency anaemia in chronic kidney disease patients in South Africa

BACKGROUND

Anaemia is a common presenting feature among patients with chronic kidney disease (CKD) and it is associated with poor clinical outcomes and quality of life. It is not clear if growth differentiation factor-15 (GDF-15) or hepcidin are useful as early markers of iron deficiency anaemia (IDA) among non-dialysis CKD patients. We therefore evaluated the diagnostic validity of GDF-15 and hepcidin as biomarkers of IDA among non-dialysis CKD patients in Johannesburg, South Africa.

METHOD

An analytic cross-sectional study was conducted among non-dialysis CKD patients (n = 312) and apparently healthy controls (n = 184) from June to December 2016 at an Academic Hospital, in Johannesburg, South Africa. An interviewer administered proforma was used to obtain the socio-biological and clinical characteristics of the participants. Serum levels of GDF-15 and hepcidin were determined. Predictive logistic regression models were built and post estimation receiver operator characteristics were determined to evaluate diagnostic validity of hepcidin and GDF-15 for absolute and functional iron deficiency anaemia.

RESULTS

About half (50.6%) of the participants were female while the participants' mean age was 49.7 ± 15.8 years. The predictive value of diagnosing absolute IDA among CKD patients using GDF-15 was 74.02% (95% CI: 67.62-80.42%) while the predictive value of diagnosing functional IDA among CKD patients using hepcidin was 70.1% (95% CI: 62.79-77.49%).There was a weak negative correlation between hepcidin levels and GFR (r = - 0.19, p = 0.04) in anaemic CKD patients, and between serum GDF-15 and haemoglobin (r = - 0.34, p = 0.001). Serum ferritin (β = 0.00389, P-value< 0.001), was a predictor of log hepcidin. MCHC (β = - 0.0220, P-value 0.005) and CKD stage (β = 0.4761, P-value < 0.001), race (β = 0.3429, P-value = 0.018) were predictors of log GDF-15. Both GDF-15 (adj OR: 1.0003, 95%CI: 1.0001-1.0005, P = 0.017) and hepcidin (adj OR: 1.003, 95%CI: 1.0004-1.0055, P = 0.023) were associated with iron deficiency anaemia after multiple linear regression modelling.

CONCLUSION

Serum GDF-15 is a potential biomarker of absolute IDA, while hepcidin levels can predict functional IDA among CKD patients.

Uremic Toxins Affect Erythropoiesis during the Course of Chronic Kidney Disease: A Review

Chronic kidney disease (CKD) is a global health problem characterized by progressive kidney failure due to uremic toxicity and the complications that arise from it. Anemia consecutive to CKD is one of its most common complications affecting nearly all patients with end-stage renal disease. Anemia is a potential cause of cardiovascular disease, faster deterioration of renal failure and mortality. Erythropoietin (produced by the kidney) and iron (provided from recycled senescent red cells) deficiencies are the main reasons that contribute to CKD-associated anemia. Indeed, accumulation of uremic toxins in blood impairs erythropoietin synthesis, compromising the growth and differentiation of red blood cells in the bone marrow, leading to a subsequent impairment of erythropoiesis. In this review, we mainly focus on the most representative uremic toxins and their effects on the molecular mechanisms underlying anemia of CKD that have been studied so far. Understanding molecular mechanisms leading to anemia due to uremic toxins could lead to the development of new treatments that will specifically target the pathophysiologic processes of anemia consecutive to CKD, such as the newly marketed erythropoiesis-stimulating agents.

Hepcidin, iron indices and bone mineral metabolism in non-dialysis chronic kidney disease

BACKGROUND

Few studies have examined the association between hepcidin, iron indices and bone mineral metabolism in non-dialysis chronic kidney disease (CKD) patients.

METHODS

We reviewed the data of 2238 patients from a large-scale multicenter prospective Korean study (2011-16) and excluded 214 patients with missing data on markers and related medications of iron and bone mineral metabolism, hemoglobin, blood pressure and causes of CKD. Multivariate linear regression analysis was used to identify the association between iron and bone mineral metabolism.

RESULTS

The proportion of CKD Stages 1-5 were 16.2, 18.7, 37.1, 21.6 and 6.4%, respectively. Per each 10% increase in transferrin saturation (TSAT), there was a 0.013 mmol/L decrease in phosphorus [95% confidence interval (CI) -0.021 to -0.004; P = 0.003] and a 0.022 nmol/L increase in logarithmic 25-hydroxyvitamin D (Ln-25OHD) levels (95% CI 0.005-0.040; P = 0.019). A 1 pmol/L increase in Ln-ferritin was associated with a 0.080 ng/L decrease in Ln-intact parathyroid hormone (Ln-iPTH; 95% CI -0.122 to -0.039; P < 0.001). Meanwhile, beta (95% CI) per 1 unit increase in phosphorus, Ln-25OHD and Ln-iPTH for the square root of the serum hepcidin were 0.594 (0.257-0.932; P = 0.001), -0.270 (-0.431 to -0.108; P = 0.001) and 0.115 (0.004-0.226; P = 0.042), respectively. In subgroup analysis, the relationship between phosphorus, 25OHD and hepcidin was strongest in the positive-inflammation group.

CONCLUSIONS

Markers of bone mineral metabolism and iron status, including hepcidin, were closely correlated to each other. Potential mechanisms of the relationship warrant further studies.

Prolyl-hydroxylase inhibitors for the treatment of anemia in chronic kidney disease

PURPOSE OF REVIEW

Prolyl-hydroxylase inhibitors are a novel class of orally administered drugs that are under development for the treatment of anemia in patients with chronic kidney disease. This review discusses the biology of these drugs and their target - hypoxia-inducible factor and potential advantages and disadvantages of these therapies. Finally, we will discuss current trials in patients with both chronic kidney disease and end-stage renal disease.

RECENT FINDINGS

Recent smaller studies have found that prolyl-hydroxylase are as effective as erythropoietin in treating anemia of chronic kidney disease. We do not yet know if they have the same cardiovascular and cancer-related risk profile and these questions will be answered by large phase III trials that are ongoing.

SUMMARY

Although prolyl hydroxylase inhibitors have much potential, questions remain regarding their efficacy and safety. Should these concerns prove to be unfounded, the treatment of anemia in chronic kidney disease will likely be transformed over the next decade.

Role of Divalent Cations in HIV-1 Replication and Pathogenicity

Divalent cations are essential for life and are fundamentally important coordinators of cellular metabolism, cell growth, host-pathogen interactions, and cell death. Specifically, for human immunodeficiency virus type-1 (HIV-1), divalent cations are required for interactions between viral and host factors that govern HIV-1 replication and pathogenicity. Homeostatic regulation of divalent cations' levels and actions appear to change as HIV-1 infection progresses and as changes occur between HIV-1 and the host. In people living with HIV-1, dietary supplementation with divalent cations may increase HIV-1 replication, whereas cation chelation may suppress HIV-1 replication and decrease disease progression. Here, we review literature on the roles of zinc (Zn2+), iron (Fe2+), manganese (Mn2+), magnesium (Mg2+), selenium (Se2+), and copper (Cu2+) in HIV-1 replication and pathogenicity, as well as evidence that divalent cation levels and actions may be targeted therapeutically in people living with HIV-1.

Depriving Iron Supply to the Virus Represents a Promising Adjuvant Therapeutic Against Viral Survival

PURPOSE OF THE REVIEW

The ongoing outbreak of novel coronavirus pneumonia (COVID-19) caused by the 2019 novel coronavirus (SARS-CoV-2) in China is lifting widespread concerns. Thus, therapeutic options are urgently needed, and will be discussed in this review.

RECENT FINDINGS

Iron-containing enzymes are required for viruses most likely including coronaviruses (CoVs) to complete their replication process. Moreover, poor prognosis occurred in the conditions of iron overload for patients upon infections of viruses. Thus, limiting iron represents a promising adjuvant strategy in treating viral infection through oral uptake or venous injection of iron chelators, or through the manipulation of the key iron regulators. For example, treatment with iron chelator deferiprone has been shown to prolong the survival of acquired immunodeficiency syndrome (AIDS) patients. Increasing intracellular iron efflux via increasing iron exporter ferroportin expression also exhibits antiviral effect on human immunodeficiency virus (HIV). The implications of other metals besides iron are also briefly discussed.

SUMMARY

For even though we know little about iron regulation in COVID-19 patients thus far, it could be deduced from other viral infections that iron chelation might be an alternative beneficial adjuvant in treating COVID-19.

Relationship between Cardiac Geometry and Serum Hepcidin in Chronic Kidney Disease: Analysis from the KNOW-CKD Study

BACKGROUND

Few studies have examined the relationship between cardiac function and geometry and serum hepcidin levels in patients with chronic kidney disease (CKD). We aimed to identify the relationship between cardiac function and geometry and serum hepcidin levels.

METHODS

We reviewed data of 1,897 patients in a large-scale multicenter prospective Korean study. Logistic regression analysis was used to identify the relationship between cardiac function and geometry and serum hepcidin levels.

RESULTS

The mean relative wall thickness (RWT) and left ventricular mass index (LVMI) were 0.38 and 42.0 g/m^2.7, respectively. The mean ejection fraction (EF) and early diastolic mitral inflow to annulus velocity ratio (E/e') were 64.1% and 9.9, respectively. Although EF and E/e' were not associated with high serum hepcidin, RWT and LVMI were significantly associated with high serum hepcidin levels in univariate logistic regression analysis. In multivariate logistic regression analysis after adjusting for variables related to anemia, bone mineral metabolism, comorbidities, and inflammation, however, only each 0.1-unit increase in RWT was associated with increased odds of high serum hepcidin (odds ratio, 1.989; 95% confidence interval, 1.358-2.916; P < 0.001). In the subgroup analysis, the independent relationship between RWT and high serum hepcidin level was valid only in women and patients with low transferrin saturation (TSAT).

CONCLUSION

Although the relationship was not cause-and-effect, increased RWT was independently associated with high serum hepcidin, particularly in women and patients with low TSAT. The relationship between cardiac geometry and serum hepcidin in CKD patients needs to be confirmed in future studies.

Prevalence, correlates and outcomes of absolute and functional iron deficiency anemia in nondialysis-dependent chronic kidney disease

Background

Anemia is associated with adverse outcomes in those with chronic kidney disease (CKD). We examined the association of absolute and functional iron deficiency anemia (IDA) with adverse outcomes (cardiovascular hospitalization, dialysis and mortality) in those with nondialysis-dependent CKD.

Methods

Nondialysis-dependent CKD patients followed in the US Veterans Administration with hemoglobin level measured within 90 days of the date of the second estimated glomerular filtration rate &lt;60 mL/min/1.73 m2 were included. Logistic regression, multivariate Cox proportional hazards and Poisson regression models adjusted for demographics and comorbidities were used to assess the prevalence and correlates of absolute [transferrin saturation (TSAT) ≤20%, ferritin &lt;100 ng/mL] and functional (TSA T≤20%, ferritin &gt;100–500 ng/mL) IDA and the associations of absolute and functional IDA with mortality, dialysis and cardiovascular hospitalization.

Results

Of 933 463 patients with CKD, 20.6% had anemia. Among those with anemia, 23.6% of patients had both TSAT and ferritin level measured, of whom 30% had absolute IDA and 19% had functional IDA. Absolute IDA in CKD was not associated with an increased risk of mortality or dialysis but was associated with a higher risk of 1-year {risk ratio [RR] 1.20 [95% confidence interval (CI) 1.12–1.28]} and 2-year cardiovascular hospitalization [RR 1.11 (95% CI 1.05–1.17)]. CKD patients with functional IDA had a higher risk of mortality [hazard ratio (HR) 1.11 (95% CI 1.07–1.14)] along with a higher risk of 1-year [RR 1.21 (95% CI 1.1–1.30)] and 2-year cardiovascular hospitalization [RR 1.13 (95% CI 1.07–1.21)]. Ferritin &gt;500 ng/mL (treated as a separate category) was only associated with an increased risk of mortality [HR 1.38 (95% CI 1.26–1.51)].

Conclusions

In a large population of CKD patients with anemia, absolute and functional IDA were associated with various clinical covariates. Functional IDA was associated with an increased risk of mortality and cardiovascular hospitalization, but absolute IDA was associated only with a higher risk of hospitalization.

Sex-specific relationships among iron status biomarkers, athletic performance, maturity, and dietary intakes in pre-adolescent and adolescent athletes

BACKGROUND

The purpose of this study was to examine relationships among biomarkers of iron status, athletic performance, growth and development, and dietary intakes in pre-adolescent and adolescent male and female athletes.

METHODS

Two-hundred and forty-nine male (n = 179) (mean ± standard deviation for age = 12.0 ± 2.1 years, height = 156.3 ± 13.9 cm, and weight = 49.1 ± 16.5 kg) and female (n = 70) (12.0 ± 2.2 years, 152.4 ± 12.3 cm, 45.3 ± 14.5 kg) athletes volunteered for capillary blood sample, anthropometric, athletic performance, and dietary intake assessments. Outcomes included maturity offset from peak height velocity, percent body fat, estimated muscle cross-sectional areas, vertical jump height (VJ), broad jump distance (BJ), pro-agility time (PA), L-cone time, 20-yard dash time (20YD), power push up (PPU) force, dietary intakes, and ferritin, soluble transferrin receptor (sTfR), and hemoglobin (Hb) concentrations.

RESULTS

Athletic performance was consistently correlated with Hb in males (r = .237-.375, p < 0.001-0.05) and with sTfR (r = .521-.649, p < 0.001-0.004) and iron intake (r = .397-.568, p = 0.001-0.027) in females. There were no relationships between dietary intakes and ferritin, sTfR, or Hb (p > 0.05). After partialing out age and height, VJ, PA, LC, and 20YD remained correlated with Hb in males (|rHb,y.Age| = .208-.322, p = 0.001-0.041; |rHb,y.Height| = .211-.321, p = 0.001-0.038). After partialing out iron intake, PA and LC remained correlated with sTfR in females (|rsTfR,y.ironintake| = .516-.569, p = 0.014-0.028).

CONCLUSIONS

Iron status biomarkers demonstrated sex-specific relationships with anaerobic exercise performance in youth athletes, which may be more dependent on maturity status and dietary intake than age. Moderate relationships between sTfR and athletic performance in adolescent female athletes emphasizes the importance of iron intake in this demographic.

The effect of nonsurgical periodontal therapy on hepcidin and on inflammatory and iron marker levels

Serum hepcidin levels may increase in response to infection and inflammation. The present study investigated the effect of nonsurgical periodontal therapy (NSPT) on levels of serum hepcidin, inflammatory markers, and iron markers. An interventional study was conducted on 67 patients (age 30-65 years) without other diseases, except for chronic periodontitis (CP). Patients were allocated to either CP or control groups. The CP group received supragingival and subgingival scaling and root planing procedures, whereas the control group received supragingival scaling. Probing depth (PD), bleeding on probing, clinical attachment level (CAL), visible plaque index (VPI), serum hepcidin and interleukin-6 (IL-6) levels, high-sensitivity C-reactive protein (hs-CRP), hematological markers, and iron markers were measured at baseline and at 90 days after NSPT. The CP group had statistically significant lower mean values for mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) (p ≤ 0.05). The control group had statistically significant reductions in hemoglobin, hematocrit, MCV, and MCH (p ≤ 0.05). Serum hepcidin, IL-6, and erythrocyte sedimentation rate (ESR) levels were significantly decreased in both groups after NSPT. Periodontal markers were more markedly reduced in the CP group compared with the control group (p ≤ 0.05). These findings suggest that NSPT may reduce the serum levels of IL-6, hepcidin, and periodontal parameters.

Hepcidin - Potential biomarker of contrast-induced acute kidney injury in patients undergoing percutaneous coronary interventions

PURPOSE

Contrast-induced acute kidney injury (CI-AKI) is a common and potentially serious complication of percutaneous coronary interventions (PCI). In this study, we tested the hypothesis whether serum and urinary hepcidin could represent early biomarkers of CI-AKI in patients with normal serum creatinine undergoing PCI. In addition, we assessed serum and urinary neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, eGFR and serum creatinine in these patients.

METHODS

Serum and urinary hepcidin and NGAL, serum cystatin C, were evaluated before, and after 2, 4, 8, 24 and 48 h after PCI using commercially available kits. Serum creatinine was assessed before, 24 and 48 h after PCI.

RESULTS

We found a significant rise in serum hepcidin as early as after 4 and 8 h when compared to the baseline values. Serum NGAL increased after 2, 4 and 8 h, and in urinary NGAL after 4, 8 and 24 h after PCI. We found a significant fall in urinary hepcidin after 8 and 24 h after PCI. Serum cystatin C increased significantly 8 h after PCI, reaching peak 24 h after PCI and then decreased after 48 h. The prevalence of CI-AKI was 8%. Urine hepcidin was significantly lower 8 and 24 h after PCI in patients with CI-AKI, while serum and urine NGAL were significantly higher in patients with CI-AKI.

CONCLUSIONS

Our findings suggest that serum hepcidin might be an early predictive biomarker of ruling out CI-AKI after PCI, thereby contributing to early patient risk stratification. However, our data needs to be validated in large cohorts with various stages of CKD.

The Role of Fibroblast Growth Factor 23 in Inflammation and Anemia

In patients with chronic kidney disease (CKD), adverse outcomes such as systemic inflammation and anemia are contributing pathologies which increase the risks for cardiovascular mortality. Amongst these complications, abnormalities in mineral metabolism and the metabolic milieu are associated with chronic inflammation and iron dysregulation, and fibroblast growth factor 23 (FGF23) is a risk factor in this context. FGF23 is a bone-derived hormone that is essential for regulating vitamin D and phosphate homeostasis. In the early stages of CKD, serum FGF23 levels rise 1000-fold above normal values in an attempt to maintain normal phosphate levels. Despite this compensatory action, clinical CKD studies have demonstrated powerful and dose-dependent associations between FGF23 levels and higher risks for mortality. A prospective pathomechanism coupling elevated serum FGF23 levels with CKD-associated anemia and cardiovascular injury is its strong association with chronic inflammation. In this review, we will examine the current experimental and clinical evidence regarding the role of FGF23 in renal physiology as well as in the pathophysiology of CKD with an emphasis on chronic inflammation and anemia.

High Prevalence of Poor Iron Status Among 8- to 16-Year-Old Youth Athletes: Interactions Among Biomarkers of Iron, Dietary Intakes, and Biological Maturity

Objective: The purpose of this study was to determine the prevalence of poor iron status in young athletes throughout the stages of iron deficiency and assess sex differences with iron deficiency in relation to growth and development and dietary intake.Methods: A cross-sectional analysis evaluated young male and female athletes (n = 91) between the ages 8 and 16 years. Anthropometric assessments, body composition, dietary intakes, and blood samples measuring ferritin, soluble transferrin receptor (sTfR), and hemoglobin (Hb) were examined. Prevalence was calculated as percentages, and independent samples t tests examined sex differences. Pearson product-moment correlation coefficient analyses quantified relationships among variables for the composite sample and each sex separately.Results: Iron depletion (low ferritin) was present in 65% and 86%, low iron levels (sTfR) in 51% and 68%, and anemia (low Hb) in 46% and 53% of the males and females, respectively. As iron deficiency progressed from low ferritin to high sTfR to anemia, prevalence decreased in both sexes, but always remained higher in females. Males were greater than females for weight, arm muscle size, and ferritin concentrations, while females were greater than males for biological maturity (p ≤ 0.05). Dietary iron intake was moderately to highly correlated (r = 0.543-0.723, p ≤ 0.05) with growth and development in females, but not males.Conclusions: Prevalence of poor iron status was higher than expected, particularly in adolescent females. Since rapid growth combined with sports participation may create high demands for iron bioavailability, emphasis may need to be placed on dietary iron intake for young athletes, particularly females.

Serum Hepcidin-25 Levels Reflect the Presence of Bacteremia in Patients with Systemic Inflammatory Response Syndrome

BACKGROUND

Hepcidin-25 is a key regulatory hormone of iron homeostasis in humans, and its production is greatly upregulated by inflammation as well as iron overload. The aim of this study was to investigate the pathophysiological role of hepcidin-25 in patients with systemic inflammatory response syndrome (SIRS).

METHODS

We enrolled 113 consecutive patients (aged 63.4±21, 50 men, 63 women), with 2 or more SIRS criteria, who were admitted to our department of general medicine between August 1, 2015 and August 31, 2017. We measured complete blood cell count and serum levels of hepcidin-25, iron, iron-binding capacity, ferritin, blood urea nitrogen, creatinine, albumin, and C-reactive protein (CRP) on admission. The patients were divided into 3 group: a bacteremia group (27 patients), a culture-negative bacterial infection group (60 patients), and a non-bacterial infection group (26 patients).

RESULTS

Hepcidin-25 levels were found to be comparable in terms of SIRS criteria: 162 [2.8-579], 193 [2.24-409], and 180 [89.2-421] ng/mL in patients with 2, 3, and 4 criteria, respectively (P=0.533). However, hepcidin-25 levels were significantly higher in the bacteremia group (209 [56.7-579] ng/mL) than in either the culture-negative bacterial infection group (168 [2.24-418] ng/mL) or the non-bacterial infection group (142 [2.8-409] ng/mL). A significant positive correlation between hepcidin-25 and CRP levels was noted in the bacteremia group (r=0.528, P=0.005) and non-bacterial infection group (r=0.648, P<0.001). Moreover, iron and ferritin levels were significantly lower in the bacteremia group than in the non-bacterial infection group.

CONCLUSIONS

Our findings suggest that hepcidin-25 level may reflect the presence of bacteremia as well as the severity of inflammation in patients with SIRS.