Changes in Hepcidin Levels in an Animal Model of Anemia of Chronic Inflammation: Mechanistic Insights Related to Iron Supplementation and Hepcidin Regulation

Critical re-evaluation of the identification of iron deficiency states and effective iron repletion strategies in patients with chronic heart failure

According to current guidelines, iron deficiency is defined by a serum ferritin level <100 ng/ml or a transferrin saturation (TSAT) <20% if the serum ferritin level is 100-299 μg/L. These criteria were developed to encourage the use of intravenous iron as an adjunct to erythropoiesis-stimulating agents in the treatment of renal anaemia. However, in patients with heart failure, these criteria are not supported by any pathophysiological or clinical evidence that they identify an absolute or functional iron deficiency state. A low baseline TSAT-but not serum ferritin level-appears to be a reliable indicator of the effect of intravenous iron to reduce major heart failure events. In randomized controlled trials, intravenous iron decreased the risk of cardiovascular death or total heart failure hospitalization in patients with a TSAT <20% (risk ratio 0.67 [0.49-0.92]) but not in patients with a TSAT ≥20% (risk ratio 0.99 [0.74-1.30]), with the magnitude of the risk reduction being proportional to the severity of hypoferraemia. Patients who were enrolled in clinical trials solely because they had a serum ferritin level <100 μg/L showed no significant benefit on heart failure outcomes, and it is noteworthy that serum ferritin levels of 20-300 μg/L lie entirely within the range of normal values for healthy adults. Current guidelines reflect the eligibility criteria of clinical trials, which inadvertently adopted unvalidated criteria to define iron deficiency. Reliance on these guidelines would lead to the treatment of many patients who are not iron deficient (serum ferritin level <100 μg/L but normal TSAT) and ignores the possibility of iron deficiency in patients with a low TSAT but with serum ferritin level of >300 μg/L. Importantly, analyses of benefit based on trial eligibility-driven guidelines substantially underestimate the magnitude of heart-failure-event risk reduction with intravenous iron in patients who are truly iron deficient. Based on all available data, we recommend a new mechanism-based and trial-tested approach that reflects the totality of evidence more faithfully than the historical process adopted by clinical investigators and by the guidelines. Until additional evidence is forthcoming, an iron deficiency state in patients with heart failure should be defined by a TSAT <20% (as long as the serum ferritin level is <400 μg/L), and furthermore, the use of a serum ferritin level <100 μg/L alone as a diagnostic criterion should be discarded.

Control variables of serum ferritin concentrations in hospitalized newborn infants: an observational study

Both iron excess and deficiency are deleterious to cellular and organ homeostasis. Serum ferritin levels serve as a biomarker of iron storage; however, their distribution and determinants in sick newborn infants remain unclear. This study aimed to investigate the reference range and independent variables of serum ferritin in hospitalized newborn infants. All newborn infants who were hospitalized at a tertiary neonatal center within 24 h of birth were retrospectively reviewed for the period of April 2015 through March 2017. Serum ferritin levels were assessed using venous blood samples obtained at admission and their independent variables were explored. The study population comprised 368 infants (36.2 ± 2.8 weeks gestation and 2319 ± 623 g at birth), whose median serum ferritin level was 149 µg/L (inter-quartile range: 81-236). The multivariable model used to explain serum ferritin values comprised hemoglobin, lactate dehydrogenase, blood pH, and maternal hypertensive disorders in pregnancy (all p < 0.01, adjusted for sex and birth weight). Serum ferritin values in hospitalized newborn infants were comparable to those previously reported using umbilical cord blood. Our novel findings indicated the association between blood pH, lactate dehydrogenase, and ferritin levels, suggesting the influence of antenatal hypoxia-ischemia and stress to serum ferritin levels.

Capsaicin Decreases Kidney Iron Deposits and Increases Hepcidin Levels in Diabetic Rats with Iron Overload: A Preliminary Study

Iron overload (IOL) increases the risk of diabetes mellitus (DM). Capsaicin (CAP), an agonist of transient receptor potential vanilloid-1 (TRPV1), reduces the effects of IOL. We evaluated the effects of chronic CAP administration on hepcidin expression, kidney iron deposits, and urinary biomarkers in a male Wistar rat model with IOL and DM (DM-IOL). IOL was induced with oral administration of iron for 12 weeks and DM was induced with streptozotocin. Four groups were studied: Healthy, DM, DM-IOL, and DM-IOL + CAP (1 mg·kg^-1·day^-1 for 12 weeks). Iron deposits were visualized with Perls tissue staining and a colorimetric assay. Serum hepcidin levels were measured with an enzyme-linked immunosorbent assay. Kidney biomarkers were assayed in 24 h urine samples. In the DM-IOL + CAP group, the total area of iron deposits and the total iron content in kidneys were smaller than those observed in both untreated DM groups. CAP administration significantly increased hepcidin levels in the DM-IOL group. Urinary levels of albumin, cystatin C, and beta-2-microglobulin were similar in all three experimental groups. In conclusion, we showed that in a DM-IOL animal model, CAP reduced renal iron deposits and increased the level of circulating hepcidin.