0
selected
-
1.
How Severe Anaemia Might Influence the Risk of Invasive Bacterial Infections in African Children.
Abuga, KM, Muriuki, JM, Williams, TN, Atkinson, SH
International journal of molecular sciences. 2020;(18)
Abstract
Severe anaemia and invasive bacterial infections are common causes of childhood sickness and death in sub-Saharan Africa. Accumulating evidence suggests that severely anaemic African children may have a higher risk of invasive bacterial infections. However, the mechanisms underlying this association remain poorly described. Severe anaemia is characterized by increased haemolysis, erythropoietic drive, gut permeability, and disruption of immune regulatory systems. These pathways are associated with dysregulation of iron homeostasis, including the downregulation of the hepatic hormone hepcidin. Increased haemolysis and low hepcidin levels potentially increase plasma, tissue and intracellular iron levels. Pathogenic bacteria require iron and/or haem to proliferate and have evolved numerous strategies to acquire labile and protein-bound iron/haem. In this review, we discuss how severe anaemia may mediate the risk of invasive bacterial infections through dysregulation of hepcidin and/or iron homeostasis, and potential studies that could be conducted to test this hypothesis.
-
2.
Plasma Ferritin and Hepcidin Are Lower at 4 Months Postpartum among Women with Elevated C-Reactive Protein or α1-Acid Glycoprotein.
Jorgensen, JM, Yang, Z, Lönnerdal, B, Chantry, CJ, Dewey, KG
The Journal of nutrition. 2017;(6):1194-1199
-
-
Free full text
-
Abstract
Background: Ferritin and hepcidin are markers of iron status that typically increase during inflammation or infection. The postpartum period is a physiologically unique life stage in which the relations between these proteins and other markers of inflammation have not been extensively studied.Objective: We aimed to determine whether 2 markers of inflammation [high-sensitivity C-reactive protein (CRP) and α1-acid glycoprotein (AGP)] were associated with ferritin or hepcidin in postpartum women in California.Methods: This is a secondary analysis of a randomized controlled iron-intervention trial. Plasma CRP, AGP, ferritin, and hepcidin were analyzed at 2 and 17 wk postpartum in 114 lactating women. We examined Pearson correlation coefficients between all biomarkers at both time points and differences in mean values of ferritin and hepcidin between those with and without elevated CRP and/or AGP.Results: At 2 and 17 wk postpartum, 58% and 26% of women had CRP >5 mg/L and 78% and 29% had AGP >1 g/L, respectively. Neither CRP nor AGP was significantly correlated with ferritin (r = 0.07 and -0.06; n = 114 at 2 wk; -0.14 and -0.14; n = 95 at 17 wk) or hepcidin (r = 0.18 and -0.03 at 2 wk; -0.05 and -0.14 at 17 wk; P > 0.05 for all). At 2 wk, geometric mean plasma ferritin and hepcidin concentrations did not differ between women with and without elevated CRP or AGP (P > 0.5), but at 17 wk women with elevated CRP or AGP had lower mean (95% CI) ferritin and hepcidin than did women without either elevated CRP or AGP [ferritin: 30.3 ng/mL (23.4, 39.1 ng/mL) compared with 40.2 ng/mL (32.9, 49.2 ng/mL); P < 0.01; hepcidin: 44.3 ng/mL (32.3, 60.9 ng/mL) compared with 67.6 ng/mL (56.1, 81.5 ng/mL); P = 0.02].Conclusion: Lower ferritin and hepcidin among women with elevated CRP or AGP at 17 wk postpartum suggests that these markers of iron status react differently to physiologic immune activation than to pathologic inflammatory states.
-
3.
Role of hepcidin-ferroportin axis in the pathophysiology, diagnosis, and treatment of anemia of chronic inflammation.
Langer, AL, Ginzburg, YZ
Hemodialysis international. International Symposium on Home Hemodialysis. 2017;(Suppl 1):S37-S46
-
-
Free full text
-
Abstract
Anemia of chronic inflammation (ACI) is a frequently diagnosed anemia and portends an independently increased morbidity and poor outcome associated with multiple underlying diseases. The pathophysiology of ACI is multifactorial, resulting from the effects of inflammatory cytokines which both directly and indirectly suppress erythropoiesis. Recent advances in molecular understanding of iron metabolism provide strong evidence that immune mediators, such as IL-6, lead to hepcidin-induced hypoferremia, iron sequestration, and decreased iron availability for erythropoiesis. The role of hepcidin-ferroportin axis in the pathophysiology of ACI is stimulating the development of new diagnostics and targeted therapies. In this review, we present an overview of and rationale for inflammation-, iron-, and erythropoiesis-related strategies currently in development.
-
4.
Rapidly Escalating Hepcidin and Associated Serum Iron Starvation Are Features of the Acute Response to Typhoid Infection in Humans.
Darton, TC, Blohmke, CJ, Giannoulatou, E, Waddington, CS, Jones, C, Sturges, P, Webster, C, Drakesmith, H, Pollard, AJ, Armitage, AE
PLoS neglected tropical diseases. 2015;(9):e0004029
Abstract
BACKGROUND Iron is a key pathogenic determinant of many infectious diseases. Hepcidin, the hormone responsible for governing systemic iron homeostasis, is widely hypothesized to represent a key component of nutritional immunity through regulating the accessibility of iron to invading microorganisms during infection. However, the deployment of hepcidin in human bacterial infections remains poorly characterized. Typhoid fever is a globally significant, human-restricted bacterial infection, but understanding of its pathogenesis, especially during the critical early phases, likewise is poorly understood. Here, we investigate alterations in hepcidin and iron/inflammatory indices following experimental human typhoid challenge. METHODOLOGY/PRINCIPAL FINDINGS Fifty study participants were challenged with Salmonella enterica serovar Typhi and monitored for evidence of typhoid fever. Serum hepcidin, ferritin, serum iron parameters, C-reactive protein (CRP), and plasma IL-6 and TNF-alpha concentrations were measured during the 14 days following challenge. We found that hepcidin concentrations were markedly higher during acute typhoid infection than at baseline. Hepcidin elevations mirrored the kinetics of fever, and were accompanied by profound hypoferremia, increased CRP and ferritin, despite only modest elevations in IL-6 and TNF-alpha in some individuals. During inflammation, the extent of hepcidin upregulation associated with the degree of hypoferremia. CONCLUSIONS/SIGNIFICANCE We demonstrate that strong hepcidin upregulation and hypoferremia, coincident with fever and systemic inflammation, are hallmarks of the early innate response to acute typhoid infection. We hypothesize that hepcidin-mediated iron redistribution into macrophages may contribute to S. Typhi pathogenesis by increasing iron availability for macrophage-tropic bacteria, and that targeting macrophage iron retention may represent a strategy for limiting infections with macrophage-tropic pathogens such as S. Typhi.
-
5.
[The role of hepcidin in iron metabolism in inflammatory bowel diseases].
Krawiec, P, Pac-Kozuchowska, E
Postepy higieny i medycyny doswiadczalnej (Online). 2014;:936-43
Abstract
Hepcidin is a 25-amino-acid peptide synthesized predominantly in hepatocytes, which plays an essential role in the regulation of systemic iron homeostasis. As a result of inflammation, hepcidin binds to ferroportin resulting in its internalization and degradation in enterocytes and macrophages. Thus iron is trapped in both enterocytes and macrophages, leading to functional hypoferremia. In iron deficiency or enhanced erythropoiesis, hepcidin expression is reduced. That fact results in increase of iron absorption and releasing iron storage from macrophages. The discovery of the biological properties of hepcidin clarified the relationship between iron homeostasis, immune response, and anaemia of chronic disease. Anaemia is the most common extra intestinal manifestation of inflammatory bowel disease. Anaemia significantly reduces the quality-of-life among patients and can lead to a number of serious complications, even life-threatening. The main types of anaemia in inflammatory bowel diseases are iron deficiency anaemia and anaemia of chronic disease. These two types of anaemia coexist commonly. The key issue is differentiation these types of anaemia to implement a proper management. Commonly used parameters as iron concentration, ferritin and transferrin, are rather unreliable indices for the evaluation of anaemia in inflammatory bowel diseases. In recent studies the important role of hepcidin as a potential alternative marker of anemia and iron status has been shown. Moreover, there are data that antihepcidin treatment may be an effective treatment of anaemia of chronic disease in inflammatory bowel disease. This paper presents hepcidin structure, mechanism of action and regulation, and highlights hepcidin function in anaemia in inflammatory bowel disease.
-
6.
Anemia of chronic disease: a unique defect of iron recycling for many different chronic diseases.
Poggiali, E, Migone De Amicis, M, Motta, I
European journal of internal medicine. 2014;(1):12-7
Abstract
Anemia of chronic disease (ACD) is frequently observed in patients with chronic diseases as a significant contributor to morbidity and mortality, which can aggravate the severity of symptoms of the underlying inflammatory status. The pathophysiology of ACD is multifactorial, including three mechanisms: shortened erythrocyte survival, impaired proliferation of erythroid progenitor cells, and abnormalities of iron metabolism. These mechanisms are "immune and inflammation"-driven, but several other factors, including chronic blood loss, hemolysis, or vitamin deficiencies, can aggravate anemia. All the abnormalities of iron metabolism observed in ACD can be explained by the effect of hepcidin upregulation. Hepcidin is a small liver peptide, that inhibits the cellular macrophage efflux of iron and intestinal iron absorption, binding to ferroportin and inducing its internalization and degradation. In ACD the synthesis of hepcidin is upregulated by increased inflammatory cytokines, causing the two main principal features: the macrophage iron sequestration and the iron-restricted erythropoiesis. ACD is the most complex anemia to treat. The recommended approach is the treatment of the underlying disease, which can lead to a major improvement or even resolution of ACD. Currently available treatments (transfusion, iron, and erythropoiesis-stimulating agents) can ameliorate anemia, but a considerable percentage of non-responders exist. On this evidence new treatment strategies might arise from the knowledge of the pathophysiology of ACD, in which hepcidin plays the central role. Prospective studies are needed to evaluate the safety and the efficacy of the new emerging treatments, which modulate hepcidin expression through different mechanisms.
-
7.
[The clinical significance of hepcidin detection in the patients with anemia and rheumatoid arthritis].
Galushko, EA
Klinicheskaia meditsina. 2014;(6):21-7
Abstract
The prevalence of anemia in patients with rheumatoid arthritis (RA) varies from 30 to 70%. 25% of the cases are diagnosed within 1 year after onset of the disease. On the whole, anemia in RA is described as anemia of a chronic disease (ACD). Pathogenesis ofACD is a multifactor process underlain by an immune mechanism: cytokines and cells ofthe reticuloendothelial system cause changes in iron homeostasis, proliferation of erythroid precursors, erythropoietin production and lifespan of erythrocytes. The key pathogenetic factor is disordered iron metabolism. IL-6 increasing hepatic production acute-phase protein (hepcidin) is the most important cytokine involved in ACD pathogenesis. Hence the necessity to measure its serum level for differential diagnostics of anemic syndrome in patients with RA and the choice of effective basal therapy. Recent data on the therapeutic potency of tocilizumab (IL-6 receptor inhibitor) demonstrate not its safety and sustainable beneficial clinical effect in combination with the favourable action on hemoglobin profile and reduction offatigue.
-
8.
Iron biology, immunology, aging, and obesity: four fields connected by the small peptide hormone hepcidin.
Dao, MC, Meydani, SN
Advances in nutrition (Bethesda, Md.). 2013;(6):602-17
-
-
Free full text
-
Abstract
Iron status and immune response become impaired in situations that involve chronic inflammation, such as obesity or aging. Little is known, however, about the additional burden that obesity may place on the iron status and immune response in the elderly. This question is relevant given the rising numbers of elderly obese (BMI >30 kg/m(2)) individuals and the high prevalence of iron deficiency worldwide. Iron is necessary for proper function of both the innate and adaptive immune system. Hepcidin, a peptide hormone that regulates cellular iron export, is essential for the maintenance of iron homeostasis. Therefore, since immune cells require iron for proper function hepcidin may also play an important role in immune response. In this review, we summarize the evidence for hepcidin as a link between the fields of gerontology, obesity, iron biology, and immunology. We also identify several gaps in knowledge and unanswered questions pertaining to iron homeostasis and immunity in obese populations. Finally, we review studies that have shown the impact of weight loss, focusing on calorie restriction, iron homeostasis, and immunity. These studies are important both in elucidating mechanistic links between obesity and health impairments and identifying possible approaches to target immune impairment and iron deficiency as comorbidities of obesity.