Hepcidin and its potential clinical utility

Physiological Role of Serum Growth Differentiation Factor-15 (GDF-15) Level and Iron Metabolism in Community-Dwelling Older Adults

Background Anemia is common in older adults and, together with heart failure and chronic kidney disease, forms a vicious cycle, whereas diseases such as chronic inflammation and cancer are associated with the anemia of chronic disease (ACD). Researchers have linked growth differentiation factor-15 (GDF-15) to a variety of conditions such as cardiovascular disease, inflammation, cancer, and kidney disease, and have reported hepcidin as a biomarker for iron regulation in ACD. Therefore, anemia, GDF-15, and hepcidin have significance in aging physiology. Hypothesis GDF-15 and hepcidin play important physiological roles in community-dwelling older adults. This study sought to explore the relationship between these biomarkers and anemia, inflammation, or other health outcomes. Methods This was a prospective study of 73 community-dwelling older adults (six men and 67 women, mean age of 76.3 years). Their serum iron level, percentage transferrin saturation (TSAT), high-sensitivity C-reactive protein (hs-CRP), and estimated glomerular filtration rate (eGFR) were measured. Enzyme-linked immunosorbent assays were used to assess their serum GDF-15, ferritin, and hepcidin levels. The participants' grip strength and walking speed were measured. The skeletal muscle mass index (SMI) of each participant was determined by bioelectrical impedance analysis. Results The GDF-15 level was significantly inversely correlated with serum iron, ferritin, and hepcidin levels; percentage TSAT; the eGFR; and gait speed. Serum hepcidin was positively correlated with levels of ferritin, albumin, and hemoglobin. Handgrip strength, SMI, and hs-CRP were not correlated with either GDF-15 or hepcidin levels. After adjusting for age, sex, and body mass index (BMI), multivariate analysis identified the log GDF-15 and serum iron level (log GDF-15: β=-0.248, iron: β=0.296) as significant factors determining hemoglobin levels, whose findings have significance due to novel results. Multivariate analysis identified eGFR and levels of hemoglobin and hepcidin as significant factors associated with log GDF-15 (eGFR: β=-0.406, hemoglobin: β=-0.269, hepcidin: β=-0.235). Similarly, ferritin and albumin levels were identified as significant factors associated with hepcidin levels (ferritin: β=0.590, Alb: β=0.277). Conclusions Anemia in community-dwelling older adults was determined not only by increasing serum iron levels but also by decreasing GDF-15 levels. Also, the increasing GDF-15 level was determined by a decreasing hepcidin level as well as the presence of anemia and renal dysfunction, and the decreasing hepcidin level was determined by decreasing stored iron and decreasing albumin levels. Serum GDF-15 and hepcidin could potentially inform diagnostic or treatment strategies for anemia or age-related health conditions.

Hepcidin Upregulation in Colorectal Cancer Associates with Accumulation of Regulatory Macrophages and Epithelial-Mesenchymal Transition and Correlates with Progression of the Disease

Advanced, metastatic colorectal cancer (CRC) is associated with high rate of mortality because of its poor responsiveness to chemotherapy/immunotherapy. Recent studies have shown that hepcidin, a peptide hormone produced mainly by hepatocytes, is expressed by and enhances the growth of tumor cells. We here assessed whether hepcidin expression helps identify subsets of CRC with advanced and aggressive course. By integrating results of in vitro/ex vivo studies with data of bioinformatics databases, we initially showed that hepcidin RNA and protein expression was more pronounced in tissue samples taken from the tumor area, as compared to the macroscopically unaffected, adjacent, colonic mucosa of CRC patients. The induction of hepcidin in the colonic epithelial cell line HCEC-1ct by interleukin (IL)-6, IL-21 and IL-23 occurred via a Stat3-dependent mechanism and, in primary CRC cells, hepcidin co-localized with active Stat3. In CRC tissue, hepcidin content correlated mainly with macrophage accumulation and IL-10 and CD206 expression, two markers of regulatory macrophages. Consistently, both IL-10 and CD206 were up-regulated by hepcidin in blood mononuclear cells. The highest levels of hepcidin were found in metastatic CRC and survival analysis showed that high expression of hepcidin associated with poor prognosis. Moreover, hepcidin expression correlated with markers of epithelial-to-mesenchymal transition and the silencing of hepcidin in CRC cells reduced epithelial-to-mesenchymal transition markers. These findings indicate that hepcidin is markedly induced in the advanced stages of CRC and suggest that it could serve as a prognostic biomarker in CRC.

Vitamin D-Mediated Anti-cancer Activity Involves Iron Homeostatic Balance Disruption and Oxidative Stress Induction in Breast Cancer

Background: Vitamin D deficiency associates with high risk of breast cancer (BRCA) and increased cellular iron. Vitamin D exerts some of its anti-cancer effects by regulating the expression of key iron regulatory genes (IRGs). The association between vitamin D and cellular iron content in BRCA remains ambiguous. Herein, we addressed whether vitamin D signaling exerts a role in cellular iron homeostasis thereby affecting survival of breast cancer cells. Methods: Expression profile of IRGs in vitamin D-treated breast cancer cells was analyzed using publicly available transcriptomic datasets. After treatment of BRCA cell lines MCF-7 and MDA-MB-231 with the active form of vitamin D, labile iron content, IRGs protein levels, oxidative stress, and cell survival were evaluated. Results: Bioinformatics analysis revealed several IRGs as well as cellular stress relates genes were differentially expressed in BRCA cells. Vitamin D treatment resulted in cellular iron depletion and differentially affected the expression of key IRGs protein levels. Vitamin D treatment exerted oxidative stress induction and alteration in the cellular redox balance by increasing the synthesis of key stress-related markers. Collectively, these effects resulted in a significant decrease in BRCA cell survival. Conclusion: These findings suggest that vitamin D disrupts cellular iron homeostasis leading to oxidative stress induction and cell death.

Serum hepcidin is increased in ANCA-associated vasculitis and correlates with activity markers

Hepcidin is a key regulator of iron metabolism and plays an important role in many pathologies. It is increased by iron administration and by inflammation, while erythropoiesis downregulates its expression. It decreases iron availability and thus contributes to anemia of chronic diseases. The aim of the study was to measure hepcidin as a marker and pathogenetic factor in ANCA-associated vasculitis (AAV). Hepcidin plasma concentration was measured by the immunological method in 59 patients with AAV and compared to patients with non-vasculitic etiology of chronic kidney disease, patients on hemodialysis (HD), with systemic lupus erythematodes (SLE) and to healthy controls and blood donors, and was correlated with the parameters of iron metabolism, inflammation, activity of the process and kidney function. Hepcidin concentration was increased in patients with AAV, SLE and HD and correlated positively with C-reactive protein, serum ferritin and creatinine, and negatively with hemoglobin and serum transferrin. In active form of AAV it correlated with the clinical scoring system (BVAS). Hepcidin can thus be considered as a pathogenetic factor of anemia in AAV and can be used for evaluation of inflammation in AAV and as an additional marker in active forms of the disease.

SRM-MS Method Development for Hepcidin-25 Peptide

As advanced mass spectrometry- (MS-) based hepcidin analysis offers to overcome the limitations in analytical methods using antihepcidin, further improvement of MS detection sensitivity for the peptide may enhance the diagnostic value of the hepcidin for various iron-related disorders. Here, improved MS detection sensitivity of hepcidin has been achieved by reducing the disulfide bonds in hepcidin, by which proton accessibility increased, compared to the intact hepcidin peptide. Comparing the ionization efficiencies of reduced and nonreduced forms of hepcidin, the reduced form of hepcidin showed an increase in ionization efficiency more than two times compared to the nonreduced form of hepcidin. We also demonstrated improved detection sensitivity of the peptide in SRM assay. We observed a significant improvement of detection sensitivity at the triple-quadrupole MS platform, that the ionization efficiency increased at least twice more, and that the limit of detection (LOD) increased more than 10 times in the concentration ranges of 1 fmol to 10 fmol of hepcidin. In this study, we demonstrated the usefulness of the hepcidin modification for overall enhancement of the ionization efficiencies of the hepcidin peptide in the MS-based quantitative measurement assay.

Increased expression of hepcidin and associated upregulation of JAK/STAT3 signaling in human gastric cancer

Gastric cancer is one of the most common malignancies with high cancer-associated mortality rate globally. Hepcidin is the peptide hormone, which is critically important in the regulation of systemic iron homeostasis. Cumulating evidence has reported that the disturbed local expression of hepcidin may serve as a predictive biomarker in assessing the clinical outcomes in a range of cancer types. However, the expression profile of hepcidin in human gastric cancer is remains to be investigated. In the present retrospective study, using archived paraffin-embedded tissue blocks, the local production of hepcidin by immunohistochemical analysis was detected, and then its correlation with clinicopathological characteristics in human gastric cancer was evaluated. In parallel, using western blotting, quantitative reverse transcription polymerase chain reaction and chromatin immunoprecipitation assay, the local status of Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signaling in response to inflammatory stimuli mediated by interleukin (IL)-6, which in turn regulates transcriptional activity of hepcidin gene (HAMP) was also assessed. The results indicated that, the local production of hepcidin was significantly elevated in tumor tissues compared with adjacent non-tumor tissues, and was tightly correlated with increasing tumor stages according to the tumor node metastasis (TNM) classification. In addition, JAK/STAT3 signaling and the STAT3 binding affinity to the HAMP gene promoter were significantly enhanced, in parallel with an increased expression of hepcidin, in tumor tissues compared with adjacent non-tumor tissues. Collectively, the present study indicated that local expression of hepcidin in gastric cancer tumor tissues was positively correlated with increasing tumor stages, which may be closely associated with the upregulation of IL-6-mediated JAK/STAT3 signaling in human gastric cancer.

Iron overload and altered iron metabolism in ovarian cancer

Iron is an essential element required for many processes within the cell. Dysregulation in iron homeostasis due to iron overload is detrimental. This nutrient is postulated to contribute to the initiation of cancer; however, the mechanisms by which this occurs remain unclear. Defining how iron promotes the development of ovarian cancers from precursor lesions is essential for developing novel therapeutic strategies. In this review, we discuss (1) how iron overload conditions may initiate ovarian cancer development, (2) dysregulated iron metabolism in cancers, (3) the interplay between bacteria, iron, and cancer, and (4) chemotherapeutic strategies targeting iron metabolism in cancer patients.

Position paper on management of iron deficiency in adult cancer patients

INTRODUCTION

Disorders of iron metabolism are commonly seen in onco-hematological clinical practice. Iron-deficiency anemia and cancer-associated anemia are usually treated with supportive therapies. Optimal management of these conditions are discussed in this perspective paper. Areas covered: A position paper discussing a number of hot topics on anemia in cancer patients is presented. The main areas covered by experts in the field are: definitions, prevalence and consequences of anemia and iron deficiency, incidence of anemia resulting from targeted therapies, importance of anemia diagnosis and monitoring, evaluation of iron status before and during treatment, role of transfusions and erythropoiesis-stimulating agents, management of iron deficiency with or without anemia, parenteral iron supplementation, role of new oral iron formulations, safety and cost issues regarding different iron compounds and administration routes. Expert commentary: Despite the availability of newer therapeutic options for its management, anemia still represents a major complication of treatment in cancer patients (surgery, chemotherapy, radiotherapy, targeted therapies), aggravating physical impairment, and negatively affecting general outcome. The view expressed by the panelists, attendees of the 4th Mediterranean Course on Iron Anemia, summarizes what they consider optimal clinical practice for screening, diagnosis, treatment and monitoring of iron deficiency and anemia in cancer patients.

Iron Metabolism in African American Women in the Second and Third Trimesters of High-Risk Pregnancies

OBJECTIVE

To examine iron metabolism during the second and third trimesters in African American women with high-risk pregnancies.

DESIGN

Longitudinal pilot study.

SETTING

Large, university-based, urban Midwestern U.S. medical center.

PARTICIPANTS

Convenience sample of 32 African American women with high-risk pregnancies seeking care at an urban maternal-fetal medicine clinic.

METHODS

Nonfasting venous blood was collected in the second and third trimesters to assess iron status, hepcidin, and systemic inflammation. Anthropometric and survey data were obtained via self-report. Descriptive statistics were calculated from these data, and changes in the clinical parameters between the second and third trimesters were evaluated via paired t tests. Associations among demographic, reproductive, anthropometric, inflammatory, and iron-related parameters were also assessed in each trimester.

RESULTS

The mean age of participants was 28.3 (± 6.8) years, and mean prepregnancy body mass index was 31.9 (± 10.7) kg/m². In the longitudinal analysis, significant (p < .05) declines in serum iron, ferritin, transferrin saturation, and C-reactive protein were observed between the second and third trimesters. There was no statistically significant change in hepcidin between trimesters. When using a ferritin level cut-point of less than 15 ng/ml and soluble transferrin receptor level of greater than 28.1 nmol/L, 48% of the participants (14 of 29) were classified with iron deficiency in the third trimester.

CONCLUSION

In this pilot study, iron deficiency was prevalent among a small cohort of African American women with high-risk pregnancies. Hepcidin concentrations were greater than previously reported in healthy, pregnant, primarily White women, which suggests decreased iron bioavailability in this high-risk group.