Oral Iron Absorption of Ferric Citrate Hydrate and Hepcidin-25 in Hemodialysis Patients: A Prospective, Multicenter, Observational Riona-Oral Iron Absorption Trial

Oral ferric citrate hydrate (FCH) is effective for iron deficiencies in hemodialysis patients; however, how iron balance in the body affects iron absorption in the intestinal tract remains unclear. This prospective observational study (Riona-Oral Iron Absorption Trial, R-OIAT, UMIN 000031406) was conducted at 42 hemodialysis centers in Japan, wherein 268 hemodialysis patients without inflammation were enrolled and treated with a fixed amount of FCH for 6 months. We assessed the predictive value of hepcidin-25 for iron absorption and iron shift between ferritin (FTN) and red blood cells (RBCs) following FCH therapy. Serum iron changes at 2 h (ΔFe2h) after FCH ingestion were evaluated as iron absorption. The primary outcome was the quantitative delineation of iron variables with respect to ΔFe2h, and the secondary outcome was the description of the predictors of the body's iron balance. Generalized estimating equations (GEEs) were used to identify the determinants of iron absorption during each phase of FCH treatment. ΔFe2h increased when hepcidin-25 and TSAT decreased (-0.459, -0.643 to -0.276, p = 0.000; -0.648, -1.099 to -0.197, p = 0.005, respectively) in GEEs. FTN increased when RBCs decreased (-1.392, -1.749 to -1.035, p = 0.000) and hepcidin-25 increased (0.297, 0.239 to 0.355, p = 0.000). Limiting erythropoiesis to maintain hemoglobin levels induces RBC reduction in hemodialysis patients, resulting in increased hepcidin-25 and FTN levels. Hepcidin-25 production may prompt an iron shift from RBC iron to FTN iron, inhibiting iron absorption even with continued FCH intake.

The association of hepcidin, reticulocyte hemoglobin equivalent and anemia-related indicators on anemia in chronic kidney disease

Hepcidin is an essential regulator of iron homeostasis in chronic kidney disease (CKD) anemia, reticulocyte hemoglobin equivalent (RET-He) can be used to evaluate the availability of iron for erythropoiesis. Previous research has found that hepcidin indirectly regulates RET-He. This study aimed to investigate the association of hepcidin, RET-He and anemia-related indicators on anemia in chronic kidney disease. A total of 230 individuals were recruited, including 40 CKD3-4 patients, 70 CKD5 patients without renal replacement therapy, 50 peritoneal dialysis patients, and 70 hemodialysis patients. The serum levels of hemoglobin (Hb), reticulocyte, RET-He, serum iron, serum creatinine, serum ferritin, total iron binding capacity, hepcidin-25, high sensitivity C-reactive protein, transferrin, erythropoietin, intrinsic factor antibody, soluble transferrin receptor and interleukins-6 (IL-6) were measured. Hepcidin-25 was positively associated with IL-6, and negatively with total iron binding capacity, intrinsic factor antibody, and transferrin. Reticulocyte Hb equivalent was associated positively with Hb, serum ferritin, serum iron, transferrin saturation, and negatively with serum creatinine, reticulocyte, IL-6, STfR. Hepcidin-25 was not associated with RET-He, while IL-6 was independently associated with hepcidin-25 and RET-He, suggesting that hepcidin has no effffect on the iron dynamics of reticulocytes in CKD, may be related to IL-6, indicate a likelihood of a threshold for stimulation of hepcidin-25 expression by IL-6 in order to indirectly regulates RET-He.

The Hepcidin-25/Ferritin Ratio Is Increased in University Rugby Players with Lower Fat Mass

Hepcidin-25 is suggested as a surrogate iron status marker in athletes who show exercise-induced anemia; however, the implications of hepcidin concentration in this population remain poorly understood. This study aimed to investigate the relationship between hepcidin and body fat levels in rugby football players. We included 40 male university rugby football players (RUG) and 40 non-athlete controls. All participants underwent an anthropometric analysis and blood testing that included both hepcidin-25 and ferritin levels. The hepcidin-25 level was slightly (11.6%, p = 0.50) higher, and the ferritin level was significantly (35.9%, p < 0.05) lower, in the RUG group than in controls. The hepcidin-25 to-ferritin ratio was significantly higher (62.5%, p < 0.05) in the RUG group. While significant U-shaped correlations were observed between the body fat and ferritin levels in both groups, the correlations between the hepcidin levels and fat mass index were significantly higher in the RUG group (RUG: r = 0.79, controls: r = 0.45). Notably, the RUG with the lower fat mass index group had a higher hepcidin-25 level, lower ferritin level, and then significantly higher hepcidin-25/ferritin ratio. The hepcidin-25/ferritin ratio may serve as a biomarker for iron status in RUG, especially RUG with lower fat mass.

The role of interleukin-6 and hepcidin 25 in the pathogenesis of anemic syndrome associated with malignant neoplasms with breast cancer patients before neoadjuvant chemotherapy

A study of interleukin-6 (IL-6), hepcidin-25 (GP-25) was conducted in 22 patients with breast cancer before neoadjuvant chemotherapy and in 27 healthy women in the control group. Significant expression of the GP-25 protein was revealed in breast cancer patients, compared to control. The rates were high both in patients with anemic sindrome (AS) and without it (p <0.01). Latent iron deficiency, AS, IDA and functional iron deficiency (FJ) were more often detected in patients with stage III disease. A significant difference in the parameters of GP-25 and IL-6 was noted, the indicators were higher in patients with stage III (p <0.01). No close correlation was found between IL-6, GP-25 and other acute-phase proteins (FR, CRP) at the initial stages of AS formation. On the contrary, a positive correlation was observed in patients with IDA and FJ between IL-6 and all acute-phase proteins (GP-25, FR, CRP). However, a small number of observations do not allow an unambiguous conclusion about the role of IL-6 and GP-25 expression in the development of AS in cancer patients with breast cancer and requires further study.

Changes in iron metabolism centered on hepcidin due to high-intensity exercise under restricted food intake

OBJECTIVES

The purpose of this study was to observe changes in iron metabolism of rats due to high-intensity exercise during reduced food intake.

METHODS

Thirty-six, 4-wk-old male Wistar rats were divided into six groups after being acclimated to running: rested control, intense exercise, 80% feeding and rested, 80% feeding and intense exercise, 70% feeding diet and rested, and 70% feeding and intense exercise groups. Only three intense exercise groups underwent acute running sessions for 30 min (30 m/min) once a day for 7 d.

RESULTS

Rats did not develop anemia with exercise and food intake restriction. Serum iron levels, transferrin saturation, hepcidin-25, and hepatic iron levels in the exercise groups were lower than those in the respective resting groups. However, these values in the 70% diet groups were slightly higher than those in the 80% diet groups. Serum erythropoietin levels decreased as food intake decreased, but the serum erythropoietin level in the 70% feeding and intense exercise group was similar to that in the rested control group. Serum interleukin-6 levels were significantly lower in the groups with restricted food intake than in the free-fed group, and exercise had no effect.

CONCLUSIONS

High-intensity exercise under restricted food intake may significantly alter the iron metabolism to maintain blood cell levels due to the strong promotion of metabolic iron utilization in response to dietary iron depletion, increased iron demand, and excretion.

Association between Consumption of Cow's Milk and Iron Deficiency Anemia in Children: Are There Roles for Hepcidin-25/Ferroportin? A Case-Control Study

Systemic iron homeostasis is regulated by the interaction of the peptide hormone, hepcidin and the iron exporter, ferroportin. The objective was to investigate the relationship between the consumption of cow's milk and iron deficiency anemia in children 2-10 years old and its association with the hepcidin-25 and ferroportin concentrations. The study population consisted of 187 prepubescent children of similar ideal body weight (IBW:90-120%); 82 children with iron deficiency anemia (37girls and 45boys; 4.27 ± 0.28 years) and 105 (47girls and 58boys; 4.25 ± 0.34 years) healthy age-sex-matched controls. Serum fasting hepcidin-25/ferroportin concentrations were measured by enzyme immunoassay in all subjects. Mean cow's milk consumption in the anemic group (373 ± 248 mL/d) tended to be higher than that in the control group (320 ± 226 mL/d), but the result was not statistically significant (p = 0.063).The mean hepcidin-25 level was significantly higher in the anemic group (19.5 ± 18.4 ng/mL) than in the healthy controls (11.0 ± 10.7, p < 0.001). The mean ferroportin level was lower in the anemic group (21.04 ± 5.74 ng/mL) than in the healthy controls (22.68 ± 4.77 ng/ml, p = 0.037). Consuming cow's milk was not associated with IDA in prepubertal children, provided that it was adequately supplemented with iron-enriched foods. We observed a significant increase in hepcidin-25 levels and a decrease in ferroportin levels in children with iron deficiency anemia compared with healthy controls. Children who consumed more cow's milk had higher levels of hepcidin-25. Iron deficiency anemia is not a concern when cow's milk is given to children if the complementary foods are rich in iron.

Human Antimicrobial Peptide Hepcidin 25-Induced Apoptosis in Candida albicans

Hepcidin 25 (hep 25) is a cysteine-rich 25-amino acid antimicrobial peptide containing the amino-terminal Cu(II)/Ni(II)-binding (ATCUN) motif. Upon metal binding, the ATCUN motif is known to be involved in the generation of reactive oxygen species (ROS), especially hydrogen peroxide and hydroxyl radicals, which act against different bacterial species. However, the antifungal activity and its correlation to the Cu(II)-ATCUN complex of Hep 25 are still poorly understood. Here, we found that ROS accumulation plays an important role in the fungicidal activity of hep 25 against Candida albicans. In addition, Annexin V-FITC staining and TUNEL assay results provide clues about the apoptosis induced by hep 25. Moreover, hep 25 also increases the generation of ROS, possibly because of copper binding to the ATCUN motif, which is relevant to its activity against C. albicans. Finally, the C. albicans killing action of hep 25 is an energy- and temperature-dependent process that does not involve targeting the membrane. Taken together, our results provide new insights into the mechanisms of hep 25 against C. albicans cells and the potential use of hep 25 and its derivatives as novel antifungal agents.

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.

Evaluation of a commercial liquid-chromatography high-resolution mass-spectrometry method for the determination of hepcidin-25

Introduction

Reliable determination of hepcidin-25, a key regulator of iron metabolism, is important. This study aimed at evaluating the performance of the Hepcidin-25 Liquid Chromatography-Tandem Mass-Spectrometry (LC-MS/MS) Kit (Immundiagnostik AG, Bensheim, Germany) for quantification of the hepcidin-25 protein.

Materials and methods

Precision, accuracy, linearity, and preanalytical requirements of the liquid-chromatography high-resolution mass-spectrometry (LC-HR-MS) method were evaluated. The imprecision and bias acceptance criteria were defined ≤ 15%. We investigated sample stability at room temperature (RT) and after repeated freeze and thaw cycles. Additionally, we assessed serum hepcidin-25 concentrations of 165 healthy adults referred for a medical check-up.

Results

The hepcidin-25 LC-MS/MS assay was linear over the concentration range of 3 – 200 ng/mL. Within- and between-run precision ranged between 1.9 – 8.6% and 5.1 – 12.4%, respectively. The mean bias of the low and high control material was - 2.7% and 2.1%, respectively. At RT, serum samples were stable for 3 h (mean bias + 0.3%). After two and three freeze and thaw cycles, hepcidin-25 concentrations showed a bias of + 8.0 and + 20%, respectively. Of 165 healthy adults, 109 females had a significantly lower median of 8.42 (range: 1.00 – 60.10) ng/mL compared to 56 males with 15.76 (range: 1.50 – 60.50) ng/mL (P = 0.002).

Conclusions

The hepcidin-25 LC-MS/MS kit shows a broad analytical range and meets the imprecision and bias acceptance criteria of ≤ 15%. Serum samples can be stored at RT for 3 h and resist up to two freeze and thaw cycles.

Iron status and dietary iron intake in vegetarians

BACKGROUND

Iron is one of the nutrients that require special consideration in a plant-based diet. The widespread belief is that meat is the best source of iron and a vegetarian diet increases the risk of its deficiency. This conviction has been the subject of analysis in a growing number of scientific reports.

OBJECTIVES

The aim of this study was to assess the iron intake and iron metabolism in vegetarians and vegans compared to a control group.

MATERIAL AND METHODS

A total of 55 vegetarians and 36 healthy volunteers were studied. The following parameters were measured in serum: iron, ferritin, transferrin, transferrin receptor, and hepcidin-25, using the enzyme-linked immunosorbent assay (ELISA) method. The dietary iron intake was assessed by a 24-h dietary recall.

RESULTS

The mean daily intake (DI) of iron was significantly higher in the female vegan group compared to the control group. Iron, hepcidin-25, ferritin and transferrin receptor in serum remained within their normal ranges. The ferritin concentration was significantly decreased and that of transferrin significantly higher in both female groups and in the male vegan group.

CONCLUSIONS

The obtained results show that the studied parameters, excluding transferrin, remained within normal ranges. However, the ferritin concentration was significantly decreased in the female vegetarian group and also in both vegan groups. This may indicate low iron storage.

Investigations of the Copper Peptide Hepcidin-25 by LC-MS/MS and NMR

Hepcidin-25 was identified as the main iron regulator in the human body, and it by binds to the sole iron-exporter ferroportin. Studies showed that the N-terminus of hepcidin is responsible for this interaction, the same N-terminus that encompasses a small copper(II)-binding site known as the ATCUN (amino-terminal Cu(II)- and Ni(II)-binding) motif. Interestingly, this copper-binding property is largely ignored in most papers dealing with hepcidin-25. In this context, detailed investigations of the complex formed between hepcidin-25 and copper could reveal insight into its biological role. The present work focuses on metal-bound hepcidin-25 that can be considered the biologically active form. The first part is devoted to the reversed-phase chromatographic separation of copper-bound and copper-free hepcidin-25 achieved by applying basic mobile phases containing 0.1% ammonia. Further, mass spectrometry (tandem mass spectrometry (MS/MS), high-resolution mass spectrometry (HRMS)) and nuclear magnetic resonance (NMR) spectroscopy were employed to characterize the copper-peptide. Lastly, a three-dimensional (3D) model of hepcidin-25 with bound copper(II) is presented. The identification of metal complexes and potential isoforms and isomers, from which the latter usually are left undetected by mass spectrometry, led to the conclusion that complementary analytical methods are needed to characterize a peptide calibrant or reference material comprehensively. Quantitative nuclear magnetic resonance (qNMR), inductively-coupled plasma mass spectrometry (ICP-MS), ion-mobility spectrometry (IMS) and chiral amino acid analysis (AAA) should be considered among others.

Early intraoperative iron-binding proteins are associated with acute kidney injury after cardiac surgery

OBJECTIVES

Iron regulation is an important modifier of renal ischemia-reperfusion injury, but the role of iron-binding proteins during cardiopulmonary bypass remains unclear. The goal was to characterize iron-binding proteins throughout ischemia-reperfusion injury to determine their association with acute kidney injury development.

METHODS

A prospective observational cohort of adult patients who underwent cardiac surgery (n = 301) was obtained, and acute kidney injury was defined by Kidney Disease Improving Global Outcomes. Serum ferritin, transferrin saturation, and urine hepcidin-25 were measured.

RESULTS

Intraoperative serum ferritin was lower at the start of cardiopulmonary bypass (P = .005) and 1-hour cardiopulmonary bypass (P = .001) in patients with acute kidney injury versus patients without acute kidney injury. Lower serum ferritin and higher transferrin saturation at 1-hour cardiopulmonary bypass were independent predictors of acute kidney injury (serum ferritin odds ratio, 0.66; 95% confidence interval [CI], 0.48-0.91; transferrin saturation odds ratio, 1.26; 95% CI, 1.02-1.55) and improved model discrimination (area under the curve [AUC], 0.76; 95% CI, 0.67-0.85) compared with clinical prediction alone (AUC, 0.72; 95% CI, 0.62-0.81; ΔAUC and net reclassification index, P = .01). Lower ferritin, higher transferrin saturation at 1-hour cardiopulmonary bypass, and lower urine hepcidin-25 at postoperative day 1 were also independent predictors for acute kidney injury development, and this model demonstrated an AUC of 0.80 (0.72-0.87), which was superior to clinical prediction (ΔAUC P = .002, integrated discrimination improvement and net reclassification index P = .003).

CONCLUSIONS

Our findings suggest that lower levels of intraoperative iron-binding proteins may reflect an impaired capacity to rapidly handle catalytic iron released during cardiopulmonary bypass, leading to kidney injury. These data highlight the importance of iron homeostasis in human ischemia-reperfusion injury and suggest it is a potentially modifiable risk during cardiac surgery. Intraoperative detection of incipient acute kidney injury may be feasible and could be used as an enrichment strategy for clinical trials.

Association between serum hepcidin-25 and primary resistance to erythropoiesis-stimulating agents in chronic kidney disease: a secondary analysis of the HERO trial

BACKGROUND

Pentoxifylline has been shown to increase haemoglobin levels in patients with chronic kidney disease (CKD) and erythropoietin-stimulating agent (ESA)-hyporesponsive anaemia in the Handling Erythropoietin Resistance with Oxpentifylline multicentre double-blind, randomized controlled trial. The present sub-study evaluated the effects of pentoxifylline on the iron-regulatory hormone hepcidin in patients with ESA-hyporesponsive CKD.

METHODS

This sub-study included 13 patients in the pentoxifylline arm (400 mg daily) and 13 in the matched placebo arm. Hepcidin-25 was measured by ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry following isolation from patient serum. Serum hepcidin-25, serum iron biomarkers, haemoglobin and ESA dosage were compared within and between the two groups.

RESULTS

Hepcidin-25 concentration at 4 months adjusted for baseline did not differ significantly in pentoxifylline versus placebo treated patients (adjusted mean difference (MD) -7.9 nmol, P = 0.114), although the difference between the groups mean translated into a >25% reduction of circulating hepcidin-25 due to pentoxifylline compared with the placebo baseline. In paired analysis, serum hepcidin-25 levels were significantly decreased at 4 months compared with baseline in the pentoxifylline group (-5.47 ± 2.27 nmol/l, P < 0.05) but not in the placebo group (2.82 ± 4.29 nmol/l, P = 0.24). Pentoxifylline did not significantly alter serum ferritin (MD 55.4 mcg/l), transferrin saturation (MD 4.04%), the dosage of ESA (MD -9.93 U/kg per week) or haemoglobin concentration (MD 5.75 g/l).

CONCLUSION

The reduction of circulating hepcidin-25 due to pentoxifylline did not reach statistical significance; however, the magnitude of the difference suggests that pentoxifylline may be a clinically and biologically meaningful modulator of hepcidin-25 in dialysis of patients with ESA-hyporesponsive anaemia.

Optimal Serum Ferritin Levels for Iron Deficiency Anemia during Oral Iron Therapy (OIT) in Japanese Hemodialysis Patients with Minor Inflammation and Benefit of Intravenous Iron Therapy for OIT-Nonresponders

Background: We determined optimal serum ferritin for oral iron therapy (OIT) in hemodialysis (HD) patients with iron deficiency anemia (IDA)/minor inflammation, and benefit of intravenous iron therapy (IIT) for OIT-nonresponders. Methods: Inclusion criteria were IDA (Hb <120 g/L, serum ferritin <227.4 pmol/L). Exclusion criteria were inflammation (C-reactive protein (CRP) ≥ 5 mg/L), bleeding, or cancer. IIT was withheld >3 months before the study. ΔHb ≥ 20 g/L above baseline or maintaining target Hb (tHB; 120-130 g/L) was considered responsive. Fifty-one patients received OIT (ferrous fumarate, 50 mg/day) for 3 months; this continued in OIT-responders but was switched to IIT (saccharated ferric oxide, 40 mg/week) in OIT-nonresponders for 4 months. All received continuous erythropoietin receptor activator (CERA). Hb, ferritin, hepcidin-25, and CERA dose were measured. Results: Demographics before OIT were similar between OIT-responders and OIT-nonresponders except low Hb and high triglycerides in OIT-nonresponders. Thirty-nine were OIT-responders with reduced CERA dose. Hb rose with a peak at 5 months. Ferritin and hepcidin-25 continuously increased. Hb positively correlated with ferritin in OIT-responders (r = 0.913, p = 0.03) till 5 months after OIT. The correlation equation estimated optimal ferritin of 30-40 ng/mL using tHb (120-130 g/L). Seven OIT-nonresponders were IIT-responders. Conclusions: Optimal serum ferritin for OIT is 67.4-89.9 pmol/L in HD patients with IDA/minor inflammation. IIT may be a second line of treatment for OIT-nonreponders.

The Impact of Human Parvovirus B19 Infection on Heart Failure and Anemia with Reference to Iron Metabolism Markers in an Adult Woman

A 35-year-old woman with fever, edema and rash was admitted. Pleural effusion and cardiomegaly were observed. A laboratory analysis revealed anemia with iron deficiency and elevated human parvovirus B19 (B19V) immunoglobulin M. The patient's hepcidin-25 and erythroferrone levels were not elevated compared to those observed later in her clinical course. On the other hand, her growth differentiation factor-15 (GDF-15) levels were elevated. She was diagnosed to have heart failure symptoms and anemia with specific iron metabolism abnormalities due to a B19V infection. After providing supportive treatment, the heart failure symptoms disappeared and her anemia had improved. This case emphasizes the need to include a B19V infection in the differential diagnosis when we encounter cases demonstrating reversible heart failure with anemia.

Association between baseline serum hepcidin levels and infection in kidney transplant recipients: Potential role for iron overload

BACKGROUND

The liver-synthesized peptide hepcidin is a key regulator of iron metabolism and correlates with total iron stores. We analyzed the association between pre-transplant hepcidin-25 levels and infection after kidney transplantation (KT).

METHODS

Serum hepcidin-25 levels were measured at baseline by high-sensitivity ELISA in 91 patients undergoing KT at our institution between December 2011 and March 2013. The impact of this biomarker on the incidence of post-transplant infection (excluding lower urinary tract infection) during the first year was assessed by Cox regression.

RESULTS

Mean hepcidin-25 level was 82.3 ± 67.4 ng/mL and strongly correlated with serum ferritin (Spearman's rho = 0.703; P < .001). There were no significant differences in hepcidin-25 levels between patients with or without overall infection (96.4 ± 67.5 vs 72.6 ± 66.7 ng/mL; P = .101). Such difference was evident for opportunistic (128.9 ± 75.0 vs 73.0 ± 62.3 ng/mL; P = .003) and, to a lesser extent, surgical-site infection (107.5 ± 73.3 vs 76.5 ± 65.2 ng/mL; P = .087). Patients with hepcidin-25 levels ≥72.5 ng/mL had higher 12-month cumulative incidence of overall infection (51.2% vs 29.2%; P = .032). After multivariate adjustment, hepcidin-25 ≥72.5 ng/mL acted as an independent risk factor for overall (adjusted hazard ratio [aHR] 3.86; 95% confidence interval [CI] 1.49-9.96; P = .005) and opportunistic infection (aHR 4.32; 95% CI 1.18-15.75; P = .027).

CONCLUSION

Elevated baseline serum hepcidin-25 levels were associated with increased risk of infection after KT, suggesting a role for iron overload in the individual susceptibility to post-transplant infection.

Quantification of hepcidin-25 in human cerebrospinal fluid using LC-MS/MS. Bioanalysis. 2017;9:337-347. [PMID: 28106476 DOI: 10.4155/bio-2016-0240]

AIM

Hepcidin, the main iron metabolism regulator, can be detected in various biological fluids. Here, we describe a quantitative method of LC-MS/MS to quantify the 25 amino acid isoform of hepcidin (hepcidin-25) in human cerebrospinal fluid (CSF). Results & methodology: Samples were prepared through protein precipitation followed by solid phase extraction (SPE) and injected into a triple-quadrupole mass spectrometer. Validation of our method included determination of LOQ (0.1 ng/ml), repeatability, intermediate precision, recovery and linearity (up to 25 ng/ml). Hepcidin-25 was subsequently quantified in 36 human CSF samples and its concentration ranged from 0.21 to 3.54 ng/ml.

CONCLUSION

This is the first time that hepcidin-25 can be reliably quantified in human CSF. This may open interesting perspectives for the management of iron-related neurological disorders.

Branched-chain amino acids reduce hepatic iron accumulation and oxidative stress in hepatitis C virus polyprotein-expressing mice

BACKGROUND & AIMS

Branched-chain amino acids (BCAA) reduce the incidence of hepatocellular carcinoma (HCC) in patients with cirrhosis. However, the mechanisms that underlie these effects remain unknown. Previously, we reported that oxidative stress in male transgenic mice that expressed hepatitis C virus polyprotein (HCVTgM) caused hepatic iron accumulation by reducing hepcidin transcription, thereby leading to HCC development. This study investigated whether long-term treatment with BCAA reduced hepatic iron accumulation and oxidative stress in iron-overloaded HCVTgM and in patients with HCV-related advanced fibrosis.

METHODS

Male HCVTgM were fed an excess-iron diet that comprised either casein or 3.0% BCAA, or a control diet, for 6 months.

RESULTS

For HCVTgM, BCAA supplementation increased the serum hepcidin-25 levels and antioxidant status [ratio of biological antioxidant potential (BAP) relative to derivatives of reactive oxygen metabolites (dROM)], decreased the hepatic iron contents, attenuated reactive oxygen species generation, and restored mitochondrial superoxide dismutase expression and mitochondrial complex I activity in the liver compared with mice fed the control diet. After 48 weeks of BCAA supplementation in patients with HCV-related advanced fibrosis, BAP/dROM and serum hepcidin-25 increased and serum ferritin decreased compared with the pretreatment levels.

CONCLUSIONS

BCAA supplementation reduced oxidative stress by restoring mitochondrial function and improved iron metabolism by increasing hepcidin-25 in both iron-overloaded HCVTgM and patients with HCV-related advanced fibrosis. These activities of BCAA may partially account for their inhibitory effects on HCC development in cirrhosis patients.

Mass spectrometry evaluation of the hepcidin-25 assay in the differential diagnosis of iron deficiency anaemia with concurrent inflammation and anaemia of inflammation in elderly patients

In this study, mass spectrometry was used to evaluate the hepcidin-25 assay in the differential diagnosis of iron deficiency anaemia with concurrent inflammation and anaemia of inflammation in elderly patients using the absence of stainable bone marrow iron as the gold standard criterion for iron deficiency (ID). In addition, correlation coefficients for hepcidin-25 vs. haematimetric and biochemical iron parameters, and C-reactive protein (CRP) were determined. The optimal cut-off for hepcidin-25 was 31.5 ng/mL corresponding to a sensitivity and specificity of 82% and 95%, respectively, for ID. For ferritin, a sensitivity and specificity of 70% and 100%, respectively, correspond to an optimal cut-off of 41.5 μg/L. Receiver operating characteristics curve analysis revealed that mass spectrometry analysis of hepcidin-25 does not appear to be superior to ferritin in the diagnosis of ID in elderly anaemic patients with concurrent inflammation. Hepcidin-25 shows a strong positive correlation with ferritin, and also correlates positively with CRP, in this patient population.

Hepcidin-25 is related to cardiovascular events in chronic haemodialysis patients

BACKGROUND

The development of atherosclerosis may be enhanced by iron accumulation in macrophages. Hepcidin-25 is a key regulator of iron homeostasis, which downregulates the cellular iron exporter ferroportin. In haemodialysis (HD) patients, hepcidin-25 levels are increased. Therefore, it is conceivable that hepcidin-25 is associated with all-cause mortality and/or fatal and non-fatal cardiovascular (CV) events in this patient group. The aim of the current analysis was to study the relationship between hepcidin-25 and all-cause mortality and both fatal and non-fatal CV events in chronic HD patients.

METHODS

Data from 405 chronic HD patients included in the CONvective TRAnsport STudy (NCT00205556) were studied (62% men, age 63.7 ± 13.9 years [mean ± SD]). The median (range) follow-up was 3.0 (0.8-6.6) years. Hepcidin-25 was measured with mass spectrometry. The relationship between hepcidin-25 and all-cause mortality or fatal and non-fatal CV events was investigated with multivariate Cox proportional hazard models.

RESULTS

Median (interquartile range) hepcidin-25 level was 13.8 (6.6-22.5) nmol/L. During follow-up, 158 (39%) patients died from any cause and 131 (32%) had a CV event. Hepcidin-25 was associated with all-cause mortality in an unadjusted model [hazard ratio (HR) 1.14 per 10 nmol/L, 95% CI 1.03-1.26; P = 0.01], but not after adjustment for all confounders including high-sensitive C-reactive protein (HR 1.02 per 10 nmol/L, 95% CI 0.87-1.20; P = 0.80). At the same time, hepcidin-25 was significantly related to fatal and non-fatal CV events in a fully adjusted model (HR 1.24 per 10 nmol/L, 95% CI 1.05-1.46, P = 0.01).

CONCLUSION

Hepcidin-25 was associated with fatal and non-fatal CV events, even after adjustment for inflammation. Furthermore, inflammation appears to be a significant confounder in the relation between hepcidin-25 and all-cause mortality. These findings suggest that hepcidin-25 might be a novel determinant of CV disease in chronic HD patients.