Serum Hepcidin Levels in Childhood-Onset Ischemic Stroke: A Case-Control Study

HMGB1 induces hepcidin upregulation in astrocytes and causes an acute iron surge and subsequent ferroptosis in the postischemic brain

Dysregulation of brain iron levels causes functional disturbances and damages neurons. Hepcidin (a peptide hormone) plays a principal role in regulating intracellular iron levels by modulating ferroportin (FPN, the only known iron exporter) through triggering its internalization and lysosomal degradation. We observed a significant and rapid iron surge in the cortices of ischemic hemispheres at 3 h after cerebral ischemia (middle cerebral artery occlusion, MCAO) that was maintained until 4 d post-MCAO. We showed upregulation of hepcidin expression in the brain as early as 3 h post-MCAO, mainly in astrocytes, and significant hepcidin accumulation in serum from 6 h post-MCAO, and these inductions were maintained for 1 day and 7 days, respectively. High mobility group box 1 (HMGB1), a prototypic danger-associated molecular pattern, accumulates markedly after transient MCAO and plays critical roles in damage aggravation via its proinflammatory effects. Here, we demonstrated that treatment with recombinant HMGB1 stimulated astrocytes to induce hepcidin expression in a TLR4- and CXCR4-dependent manner. Furthermore, hepcidin-mediated intracellular iron accumulation in neurons was confirmed by an experiment using N-methyl-D-aspartate (NMDA)-conditioned medium-treated primary astrocytes and fresh primary cortical neurons treated with hepcidin-containing astrocyte-conditioned medium. Moreover, HMGB1-mediated local hepcidin upregulation and subsequent local iron surge were found to cause ferroptosis in the postischemic brain, which was suppressed by the functional blocking of HMGB1 using intranasally administered HMGB1 A box or anti-HMGB1 antibody. These findings show that HMGB1 serves as a ferroptosis inducer by upregulating hepcidin in astrocytes and thus aggravates acute damage in the postischemic brain.

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.

Systemic hepcidin quantified with LC-MS/MS in dementia in association with disease pathology and severity and with structural changes in the brain

Hepcidin is a peptide hormone regulating iron metabolism, the dyshomeostasis of which has been implicated in dementia. Yet, data on hepcidin status in dementia are scanty, limited to Alzheimer's disease (AD) and inconsistent due to methodological problems with its determination using immunoassays and/or lack of homogeneity of evaluated groups. Hepcidin association with vascular dementia (VaD) remains unknown. We proposed a mass spectrometry method of hepcidin quantification in sera and aimed at determining hepcidin systemic status in patients with dementia of AD, VaD, or mixed (MD) pathology, with reference to the degree of cognitive loss and structural changes in the brain as well as at evaluating the diagnostic potential of hepcidin as a biomarker. We found that hepcidin concentrations were significantly elevated in VaD and insignificantly so in AD or MD and that they positively correlated with the Clinical Dementia Rating and inversely with the Mini Mental State Examination. Hepcidin tended to be more pronouncedly elevated in patients with advanced cortical atrophy and white matter lesions. It displayed a biphasic relationship with the Hachinski Ischemic Scale and a good accuracy as dementia but not differential marker. Taken together, our results demonstrated that dementia of vascular and not neurodegenerative pathology is associated with significant elevation of systemic hepcidin. Hepcidin elevation reflects the degree of cognitive loss as well as the severity of structural changes in the brain. If confirmed in a prospective study, hepcidin quantification may hold promise as a diagnostic marker; its accuracy as a differential marker of VaD is insufficient.

Hepcidin, an emerging and important player in brain iron homeostasis

Hepcidin is emerging as a new important factor in brain iron homeostasis. Studies suggest that there are two sources of hepcidin in the brain; one is local and the other comes from the circulation. Little is known about the molecular mediators of local hepcidin expression, but inflammation and iron-load have been shown to induce hepcidin expression in the brain. The most important source of hepcidin in the brain are glial cells. Role of hepcidin in brain functions has been observed during neuronal iron-load and brain hemorrhage, where secretion of abundant hepcidin is related with the severity of brain damage. This damage can be reversed by blocking systemic and local hepcidin secretion. Studies have yet to unveil its role in other brain conditions, but the rationale exists, since these conditions are characterized by overexpression of the factors that stimulate brain hepcidin expression, such as inflammation, hypoxia and iron-overload.

Anaemia is an essential complication of ANCA-associated renal vasculitis: a single center cohort study

BACKGROUND

Anaemia is a common complication of patients with antineutrophil cytoplasmic antibody (ANCA)-associated renal vasculitis. Nevertheless, the cause and degree of such cases of anaemia have not been elucidated in detail. We aimed to investigate the prevalence, cause, pathogenesis of anaemia and the impact of anaemia on prognosis in patients with ANCA-associated renal vasculitis.

METHODS

We identified 45 patients with ANCA-associated renal vasculitis that were clinically and/or histologically diagnosed and treated from 2003 to 2014 at University of Tsukuba Hospital. The relationships between anaemia and various clinicopathological findings were evaluated.

RESULTS

At the time of diagnosis of ANCA-associated renal vasculitis, all patients showed anaemia, with a mean haemoglobin level of 7.5 ± 1.3 g/dL. Renal anaemia was diagnosed in 92% of patients, anaemia of chronic disease (ACD) in 56%, and anaemia due to hemorrhage in 20%. Next, the patients were divided into two groups according to anaemia severity: minimum haemoglobin (min Hb) < 7.5 (n = 24) and min Hb ≥ 7.5 (n = 21). A comparison of baseline characteristics showed that serum albumin, maximum serum creatinine, minimum estimated glomerular filtration rate (eGFR), serum cystatin C, and the area of tubulointerstitial damage were significantly different between the haemoglobin groups (p <  0.05). No significant intergroup differences were observed in iron-related or inflammation-related data. With regard to the relationship between anaemia severity and prognosis, patients in the min Hb < 7.5 group tended to have a lower eGFR. Anaemia severity was associated with markedly lower survival (Log-rank test, p = 0.03).

CONCLUSIONS

In this cohort of patients with ANCA-associated renal vasculitis, all subjects exhibited anaemia. In regard to the cause and pathogenesis, the most prevalent form of anaemia was renal anaemia, not ACD, and a potential reason for the high prevalence of anaemia in our cohort may have been the interaction between renal anaemia and ACD. Moreover, anaemia severity was significantly associated with the degree of renal dysfunction and life prognosis.