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Field Trials of Food Fortification with Iron: The Experience in Chile
Published in Bo Lönnerdal, Iron Metabolism in Infants, 2020
Tomás Walter, Manuel Olivares, Eva Hertrampf
In 1977, Hertrampf and co-workers31 initiated investigations oriented to the possible use of hemoglobin in food fortification in Chile. Initially the studies were focused on the fortification of milk. Three heme iron concentrates were obtained from bovine red cells: hemoglobin with stroma, hemoglobin without stroma, and hemin. The three concentrates were tested separately. When added to milk in a concentration of 15 mg elemental iron per liter, there was no change in flavor and the color of the fortified milk was that of cafe-aulait. Radioisotope absorption studies with intrinsic labeled hemoglobin preparations obtained from a Fe-labeled calf were conducted enrolling 70 infants 6 to 18 months of age. Absorption of each of the three heme iron concentrates was similar, with a geometric mean of 18.8%. Absorption of hemin was significantly higher in milk than in water, indicating that milk probably protected hemin from forming insoluble macromolecular aggregates. Hemoglobin added to milk, however, produced rapid rancidity of the product due to the oxidation of fat in the powdered milk. Hemoglobin fortification of milk was thus judged to be impractical. The lower fat content of cookies prompted studies of their use in heme fortification. During 1980 to 1982, INTA conducted studies to explore the feasibility of fortifying cookies with heme and, subsequently, the practicability of incorporating the cookies into the national program directed at school children.32
Liver Diseases
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
In the mechanism of hemoglobin breakdown to bilirubin, several intermediates have been suggested (Figure 16). Hematin is considered to be a normal intermediary. In intravascular hemolysis such as hematin icterus, the production of hematin is increased without bilirubin elevation. Lack of hyperbilirubinemia suggests a shift in the normal metabolism to the accumulation of hematin. Animal experiments using labeled hemin are in agreement with the formation of this intermediate. The formation of choleglobin or verdohemoglobin, a green iron-containing protein complex, has also been proposed. By successive oxidation, the α-methene bridge is replaced by an ether bond. The next step leads to loss of iron and protein, and the biliverdin formed is reduced to bilirubin. The presence of biliverdin reductase and heme-α-methenyl oxygenase in the liver and kidney provides evidence for the existence of this pathway. Verdoglobinuria occurs in Pseudomonas septicemia, indicating that the bacterial toxin interferes with the complete metabolism of hemoglobin, resulting in the accumulation of verdoglobin.418,533
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Published in Anton Sebastian, A Dictionary of the History of Medicine, 2018
Hemin Chloride of ferric protoporphyrin or hematin in blood, first used as an indicator for detection of blood in forensic medicine by German histologist, Ludwig Teichmann (1823–1895) in 1853. He treated the blood sample or material with acetic acid and sodium chloride in order to reveal the formation of hemin in positive cases. This was used in legal medicine for over a century.
Porphyria: awareness is the key to diagnosis!
Published in Acta Clinica Belgica, 2022
Benjamin Heymans, Wouter Meersseman
Anytime there is a strong suspected or confirmed case of AIP, hemin should be administered promptly. This is especially the case when signs of severe disease are present like neurological symptoms or severe hyponatremia. Hemin is given once daily through a large vein or central line, in a dose of 3 to 4 mg per kg of body weight [2]. It acts by replenishing the pool of free haem in the hepatocytes and thus reducing the expression of ALAS1 (as does caloric repletion with glucose in a minor way). Because of the indirect effects, symptoms only begin to improve 2 to 4 days after the first administration of hemin [1]. At the same time, the concentration of PBG in urine and plasma will start to drop. Several factors may lead to an absence in resolution of symptoms, such as an insufficient dosing, chronic porphyria-related pathology, as well as symptoms not caused by the porphyria. In general, hemin is needed in two thirds of the AIP attacks [1]. In milder forms, a glucose infusion together with supportive measures might be sufficient to resolve the symptoms. The major side effects of hemin administration are phlebitis (which can largely be avoided by administering it together with albumin), temporary induction of platelet aggregation and hepatic iron accumulation. (Figure 1).
Givosiran for the treatment of acute hepatic porphyria
Published in Expert Review of Clinical Pharmacology, 2022
Until recently, the only available and approved approach for AHPs was to treat APAs by intravenous hemin infusions, whereas no well-defined strategies had been implemented for the prevention of recurrent attacks or for chronic manifestations. For patients with recurrent attacks, an ‘off-label’ maintenance therapy with periodic hemin infusions has been used in some porphyria specialist centers, even in the absence of specific randomized controlled trials or shared recommendations. The long-term consequences of AHPs would take their toll on patients’ health, particularly in terms of worsening neuropathy, development of hepatocellular carcinoma, or decline in renal function to a terminal stage. It should be underscored that the only curative option for patients with AHPs is currently represented by liver transplantation [74], a complex and deeply invasive intervention that, also as a consequence of organ shortage, may be offered only to a limited number of selected patients. Even in that case, chronic manifestations of AHPs can resolve only partially, and combined liver–kidney transplantation has sometimes been attempted to treat end-stage (porphyria-associated) chronic kidney disease [75,76].
Ramatroban for chemoprophylaxis and treatment of COVID-19: David takes on Goliath
Published in Expert Opinion on Therapeutic Targets, 2022
Kate C. Chiang, John G. Rizk, Deanna J. Nelson, Lakshmanan Krishnamurti, Selvakumar Subbian, John D. Imig, Imran Khan, Srinivasa T. Reddy, Ajay Gupta
COVID-19 is associated with complement-mediated thrombotic microangiopathy and hemolysis, especially in children [19]. Upon release, the reduced heme is rapidly and spontaneously oxidized in the blood into its ferric (Fe3+) form, hemin, with increased levels observed in hemolytic diseases [155]. Hemin activates platelets by serving as a ligand for C-type-lectin-like receptor 2 (CLEC2) [155]. Upon activation, the CLEC2 receptor undergoes tyrosine phosphorylation mediated by TxA2 [147]. This leads to downstream phosphorylation of spleen tyrosine kinase and phospholipase γ2, potentiated by TxA2 [147]. This cooperation between CLEC2 and TxA2 signaling is critical for platelet activation in hemolytic states [147]. Platelet activation leads to the release of exosomes and microvesicles, which further activate CLEC5A on neutrophils and TLR2 on macrophages, thereby inducing NET formation and pro-inflammatory cytokine release [156]. The potentiation of CLEC2 signaling by TxA2 was abolished by 10 µM ramatroban; by comparison, 1 mM aspirin was largely ineffective [147] (Table 1). Therefore, ramatroban may be more effective than aspirin in abrogating TxA2-dependent CLEC2 signaling, platelet activation, and thromboinflammation in COVID-19 associated thrombotic microangiopathy.