1.
Iron Acquisition by Bacterial Pathogens: Beyond Tris-Catecholate Complexes.
Zhang, Y, Sen, S, Giedroc, DP
Chembiochem : a European journal of chemical biology. 2020;(14):1955-1967
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Abstract
Sequestration of the essential nutrient iron from bacterial invaders that colonize the vertebrate host is a central feature of nutritional immunity and the "fight over transition metals" at the host-pathogen interface. The iron quota for many bacterial pathogens is large, as iron enzymes often make up a significant share of the metalloproteome. Iron enzymes play critical roles in respiration, energy metabolism, and other cellular processes by catalyzing a wide range of oxidation-reduction, electron transfer, and oxygen activation reactions. In this Concept article, we discuss recent insights into the diverse ways that bacterial pathogens acquire this essential nutrient, beyond the well-characterized tris-catecholate FeIII complexes, in competition and cooperation with significant host efforts to cripple these processes. We also discuss pathogen strategies to adapt their metabolism to less-than-optimal iron concentrations, and briefly speculate on what might be an integrated adaptive response to the concurrent limitation of both iron and zinc in the infected host.
2.
Differences between intravenous iron products: focus on treatment of iron deficiency in chronic heart failure patients.
Martin-Malo, A, Borchard, G, Flühmann, B, Mori, C, Silverberg, D, Jankowska, EA
ESC heart failure. 2019;(2):241-253
Abstract
Iron deficiency is the leading cause of anaemia and is highly prevalent in patients with chronic heart failure (CHF). Iron deficiency, with or without anaemia, can be corrected with intravenous (i.v.) iron therapy. In heart failure patients, iron status screening, diagnosis, and treatment of iron deficiency with ferric carboxymaltose are recommended by the 2016 European Society of Cardiology guidelines, based on results of two randomized controlled trials in CHF patients with iron deficiency. All i.v. iron complexes consist of a polynuclear Fe(III)-oxyhydroxide/oxide core that is stabilized with a compound-specific carbohydrate, which strongly influences their physico-chemical properties (e.g. molecular weight distribution, complex stability, and labile iron content). Thus, the carbohydrate determines the metabolic fate of the complex, affecting its pharmacokinetic/pharmacodynamic profile and interactions with the innate immune system. Accordingly, i.v. iron products belong to the new class of non-biological complex drugs for which regulatory authorities recognized the need for more detailed characterization by orthogonal methods, particularly when assessing generic/follow-on products. Evaluation of published clinical and non-clinical studies with different i.v. iron products in this review suggests that study results obtained with one i.v. iron product should not be assumed to be equivalent to other i.v. iron products that lack comparable study data in CHF. Without head-to-head clinical studies proving the therapeutic equivalence of other i.v. iron products with ferric carboxymaltose, in the highly vulnerable population of heart failure patients, extrapolation of results and substitution with a different i.v. iron product is not recommended.