The impact of chelation compliance in health outcome and health related quality of life in thalassaemia patients: a systematic review.

Understanding consequences of poor chelation compliance is crucial given the enormous burden of post-transfusional iron overload complications. We systematically reviewed iron-chelation therapy (ICT) compliance, and the relationship between compliance with health outcome and health-related quality of life (HRQoL) in thalassaemia patients. Several reviewers performed systematic search strategy of literature through PubMed, Scopus, and EBSCOhost. The preferred reporting items of systematic reviews and meta-analyses (PRISMA) guidelines were followed. Of 4917 studies, 20 publications were included. The ICT compliance rate ranges from 20.93 to 75.3%. It also varied per agent, ranging from 48.84 to 85.1% for desferioxamine, 87.2-92.2% for deferiprone and 90-100% for deferasirox. Majority of studies (N = 10/11, 90.91%) demonstrated significantly negative correlation between compliance and serum ferritin, while numerous studies revealed poor ICT compliance linked with increased risk of liver disease (N = 4/7, 57.14%) and cardiac disease (N = 6/8, 75%), endocrinologic morbidity (N = 4/5, 90%), and lower HRQoL (N = 4/6, 66.67%). Inadequate compliance to ICT therapy is common. Higher compliance is correlated with lower serum ferritin, lower risk of complications, and higher HRQoL. These findings should be interpreted with caution given the few numbers of evidence.

Effects on hearing after long-term use of iron chelators in beta-thalassemia: Over twenty years of longitudinal follow-up.

OBJECTIVE: The role of iron chelation in causing hearing loss (HL) is still unclear. The present study assessed the prevalence of HL among transfusion-dependent thalassemia (TDT) patients who underwent audiological follow-up over a 20-year period. METHODS: We retrospectively analyzed clinical records and audiological tests from January 1990 (T0) to December 2022 (T22) of a group of TDT patients who received iron chelation therapy with deferoxamine (DFO), deferiprone (DFP) or deferasirox (DFX), in monotherapy or as part of combination therapy. RESULTS: A total of 42 adult TDT patients (18 male, 24 female; age range: 41-55 years; mean age: 49.2 ± 3.7 years) were included in the study. At the T22 assessment, the overall prevalence of sensorineural HL was 23.8 % (10/42). When patients were stratified into two groups, with and without ototoxicity, no differences were observed for sex, age, BMI, creatinine level, pre-transfusional hemoglobin, start of transfusions, cardiac or hepatic T2 MRI; only ferritin serum values and duration of chelation were significantly higher (p = 0.02 and p = 0.01, respectively) in patients with hearing impairment in comparison to those with normal hearing. CONCLUSION: This study with long-term follow-up suggests that iron chelation therapy might induce ototoxicity; therefore, a long and accurate audiological follow-up should be performed in TDT patients.

Drug Selection and Posology, Optimal Therapies and Risk/Benefit Assessment in Medicine: The Paradigm of Iron-Chelating Drugs.

The design of clinical protocols and the selection of drugs with appropriate posology are critical parameters for therapeutic outcomes. Optimal therapeutic protocols could ideally be designed in all diseases including for millions of patients affected by excess iron deposition (EID) toxicity based on personalised medicine parameters, as well as many variations and limitations. EID is an adverse prognostic factor for all diseases and especially for millions of chronically red-blood-cell-transfused patients. Differences in iron chelation therapy posology cause disappointing results in neurodegenerative diseases at low doses, but lifesaving outcomes in thalassemia major (TM) when using higher doses. In particular, the transformation of TM from a fatal to a chronic disease has been achieved using effective doses of oral deferiprone (L1), which improved compliance and cleared excess toxic iron from the heart associated with increased mortality in TM. Furthermore, effective L1 and L1/deferoxamine combination posology resulted in the complete elimination of EID and the maintenance of normal iron store levels in TM. The selection of effective chelation protocols has been monitored by MRI T2* diagnosis for EID levels in different organs. Millions of other iron-loaded patients with sickle cell anemia, myelodysplasia and haemopoietic stem cell transplantation, or non-iron-loaded categories with EID in different organs could also benefit from such chelation therapy advances. Drawbacks of chelation therapy include drug toxicity in some patients and also the wide use of suboptimal chelation protocols, resulting in ineffective therapies. Drug metabolic effects, and interactions with other metals, drugs and dietary molecules also affected iron chelation therapy. Drug selection and the identification of effective or optimal dose protocols are essential for positive therapeutic outcomes in the use of chelating drugs in TM and other iron-loaded and non-iron-loaded conditions, as well as general iron toxicity.

Successful chelation in beta-thalassemia major in the 21st century.

This century has seen a revolution the management of beta-thalassemia major. Over a 12-year period to 2016, we aimed to analyze the benefits of such advances. In 209 patients, independent of the chelation regimen, ferritin, cardiac T2* and liver iron concentration changes were evaluated. We defined chelation success (ChS) as no iron load in the heart and acceptable levels in the liver. Over 3 early magnetic resonance imagings, the same parameters were assessed in 2 subgroups, the only 2 that had sufficient patients continuing on 1 regimen and for a significant period of time, 1 on deferrioxamine (low iron load patients n = 41, Group A) and 1 on deferoxamine-deferiprone (iron overloaded n = 60, Group B). Finally, 28 deaths and causes were compared to those of an earlier period. The 209 patients significantly optimized those indices, while the number of patients with chelation success, increased from 6% to 51% (P < .0001). In group A, ChS after about 8 years increased from 21 to 46% (P = .006), while in Group B, from 0% to 60% (P < .001) after about 7 years. Deaths over the 2 periods showed significant reduction. Combined clearance of cardiac and liver iron (ChS) is feasible and should become the new target for all patients. This requires, serial magnetic resonance imagings and often prolonged intensified chelation for patients.

Combination chelation therapy.

Combination chelation therapies are considered in transfusion-dependent thalassemia patients for whom monotherapy regimens have failed to achieve iron balance or intensification of iron chelation therapy is required for the rapid reduction of excess iron to avoid permanent organ damage. Combination chelation may provide a more flexible approach for individualizing chelation therapy, thereby improving tolerability, adherence, and quality of life. In principle, iron chelators can be combined with an infinite number of dosing regimens; these involve simultaneous or sequential exposure to the chelators on the same day or alternating the drugs on different days. Clinical studies have established the safety and efficacy of chelation combinations. However, real-life data with combination therapies indicate the significance of compliance for a meaningful reduction in iron overload compared to monotherapies.

Clinical Challenges with Iron Chelation in Beta Thalassemia.

Conventional therapy for severe thalassemia includes regular red cell transfusions and iron chelation therapy to prevent and treat complications of iron overload. Iron chelation is very effective when appropriately used, but inadequate iron chelation therapy continues to contribute to preventable morbidity and mortality in transfusion-dependent thalassemia. Factors that contribute to suboptimal iron chelation include poor adherence, variable pharmacokinetics, chelator adverse effects, and difficulties with precise monitoring of response. The regular assessment of adherence, adverse effects, and iron burden with appropriate treatment adjustments is necessary to optimize patient outcomes.

Lifting the iron curtain of vision.

Ocular and specifically retinal toxicities of systemic medications are prevalent and encompass many disease modalities. For many of these pharmaceuticals, established follow-up protocols are in place to ensure timely detection and cessation of therapy. However, while for some disorders, cessation of therapy is a viable option due to existing treatment alternatives, for some others cessation of treatment can be life threatening and/or shorten the patient's life expectancy. Such is the case for iron chelating agents used in transfusion-dependent patients of Thalassemia, of which deferoxamine (DFO) is the most widely used. In their recent article in EMBO Molecular Medicine, Kong et al (2023) addressed the issue of DFO-induced retinal toxicity used both in vivo and in vitro techniques. Their study suggests a potentially protective role for α-ketoglutarate (AKG) supplementation against DFO toxicity.

Iron chelation therapy.

Iron overload is a pathological condition resulting from a congenital impairment of its regulation, increased intestinal iron absorption secondary to bone marrow erythroid hyperplasia, or a chronic transfusional regimen. In normal conditions, intracellular and systemic mechanisms contribute to maintaining iron balance. When this complex homeostatic mechanism fails, an iron overload could be present. Detecting an iron overload is not easy. The gold standard remains the liver biopsy, even if it is invasive and dangerous. Identifying iron using noninvasive techniques allowed a better understanding of the rate of iron overload in different organs, with a low risk for the patient. Estimating serum ferritin (mg/L) is the easiest and, consequently, the most employed diagnostic tool for assessing body iron stores, even if it could be a not specific method. The most common hematological causes of iron overload are myelodysplastic syndromes, sickle cell disease, and thalassemia. In all of these conditions, three drugs have been approved for the treatment of iron overload: deferiprone, deferoxamine, and deferasirox. These chelators have been demonstrated to help lower tissue iron levels and prevent iron overload complications, improving event-free survival (EFS). Nowadays, the decision to start chelation and which chelator to choose remains the joint decision of the clinician and patient.

Amelioration effects of the soybean lecithin-gallic acid complex on iron-overload-induced oxidative stress and liver damage in C57BL/6J mice.

CONTEXT: Gallic acid (GA) and lecithin showed important roles in antioxidant and drug delivery, respectively. A complex synthesized from GA and soybean lecithin (SL-GAC), significantly improved bioavailability of GA and pharmacological activities. However, the antioxidant activity of SL-GAC and its effect on iron-overload-induced liver injury remains unexplored. OBJECTIVE: This study investigates the antioxidant properties of SL-GAC in vitro and in mice, and its remediating effects against liver injury by iron-overloaded. MATERIALS AND METHODS: In vitro, free radical scavenging activity, lipid peroxidation inhibition, and ferric reducing power of SL-GAC were measured by absorbance photometry. In vivo, C57BL/6J mice were randomized into 4 groups: control, iron-overloaded, iron-overloaded + deferoxamine, and iron-overloaded + SL-GAC. Treatments with deferoxamine (150 mg/kg/intraperitioneally) and SL-GAC (200 mg/kg/orally) were given to the desired groups for 12 weeks, daily. Iron levels, oxidative stress, and biochemical parameters were determined by histopathological examination and molecular biological techniques. RESULTS: In vitro, SL-GAC showed DPPH and ABTS free radicals scavenging activity with IC50 values equal to 24.92 and 128.36 µg/mL, respectively. In C57BL/6J mice, SL-GAC significantly reduced the levels of serum iron (22.82%), liver iron (50.29%), aspartate transaminase (25.97%), alanine transaminase (38.07%), gamma glutamyl transferase (42.11%), malondialdehyde (19.82%), total cholesterol (45.96%), triglyceride (34.90%), ferritin light chain (18.51%) and transferrin receptor (27.39%), while up-regulated the levels of superoxide dismutase (24.69%), and glutathione (11.91%). CONCLUSIONS: These findings encourage the use of SL-GAC to treat liver injury induced by iron-overloaded. Further in vivo and in vitro studies are needed to validate its potential in clinical medicine.

Aluminum overload in the reverse osmosis dialysis era: does it exist?

BACKGROUND: Aluminum accumulation is a well-described complication in dialysis patients. Improvements in hemodialysis technology have possibly eliminated the occurrence of aluminum overload. Limited evidence suggests that aluminum overload may decline in the era of aluminum removal from dialysis fluids, even with the use of aluminum binders. METHODS: We examined the data from January 2014 to June 1, 2020, identified through our electronic records, to evaluate the desferrioxamine (DFO) test results for aluminum overload. The presentation and treatment of aluminum overload were recorded. RESULTS: Ninety-nine dialysis patients were enrolled for the DFO test. Forty-seven patients (47.5%) were identified as DFO test positive for aluminum overload, of which 14 (14/47) patients had symptoms, including one patient with an unexplained fracture, eight patients with unexplained anemia despite high-dose erythropoiesis-stimulating agents, and five patients with hypercalcemia (serum calcium >11 mg dL-1). None of the patients with aluminum overload developed encephalopathy. Only four of the 47 patients had microcytic anemia. Patients requiring longer treatments (>10 months versus <10 months) had similar basal serum aluminum (p = 0.219) but had an increase in serum aluminum after DFO (p = 0.041). Furthermore, the treatments decreased erythropoietin doses in the aluminum overload group, with serum total alkaline phosphatase levels <60 U L-1 (p = 0.028). CONCLUSION: We concluded that aluminum overload existed in the reverse osmosis dialysis era. In light of non-obvious symptoms, such as anemia and bone turnover change, serum aluminum in dialysis patients should be monitored in countries using aluminum-based phosphate binders, despite reverse osmosis dialysis.

New Deferric Amine Compounds Efficiently Chelate Excess Iron to Treat Iron Overload Disorders and to Prevent Ferroptosis.

Excess iron accumulation occurs in organs of patients with certain genetic disorders or after repeated transfusions. No physiological mechanism is available to excrete excess iron and iron overload to promote lipid peroxidation to induce ferroptosis, thus iron chelation becomes critical for preventing ion toxicity in these patients. To date, several iron chelators have been approved for iron chelation therapy, such as deferiprone and deferoxamine, but the current iron chelators suffer from significant limitations. In this context, new agents are continuously sought. Here, a library of new deferric amine compounds (DFAs) with adjustable skeleton and flexibility is synthesized by adopting the beneficial properties of conventional chelators. After careful evaluations, compound DFA1 is found to have greater efficacy in binding iron through two molecular oxygens in the phenolic hydroxyl group and the nitrogen atom in the amine with a 2:1 stoichiometry. This compound remarkably ameliorates iron overload in diverse murine models through both oral and intravenous administration, including hemochromatosis, high iron diet-induced, and iron dextran-stimulated iron accumulation. Strikingly, this compound is found to suppress iron-induced ferroptosis by modulating the intracellular signaling that drives lipid peroxidation. This study opens a new approach for the development of iron chelators to treat iron overload.

A Composite Deferoxamine/Black Phosphorus Nanosheet/Gelatin Hydrogel Scaffold for Ischemic Tibial Bone Repair.

Introduction: Bone delay union is mostly caused by lack of blood supply. Although autografts, allografts and artificial bone have been widely used to treat bone delay union, the bone regeneration fails in the ischemic site accompanied by the bone donor site complications and disease transmission. Recently, there is a growing recognition of the importance of hydrogel scaffolds which are regarded as an eligible engineer tissue for bone repair. However, hydrogel is still limited in improving neovascularization. Methods: In this work, black phosphorus nanosheet and deferoxamine (BPN-DFO) were loaded in the gelatin hydrogel to overcome the high risk of bone delay union and systemically investigated the regeneration capability of BPN-DFO hydrogel in vitro and vivo. Results: The resulting BPN-DFO hydrogel scaffold showed superior swollen, degradation and release rate, as well as satisfied biocompatibility. BPN-DFO hydrogel shown the significant up-expression of mRNA related to bone regeneration and cell proliferation. In vivo, the proposed BPN-DFO hydrogel significantly improved osteogenesis and neovascularization in the ischemic tibial bone site of SD rats with acute femoral artery occlusion. Both macroscopic and histological evaluation of new regenerated bone showed newly formed blood vessel and collagen using BPN-DFO hydrogel. The immunohistochemistry and RT-PCR revealed that the bone regeneration could be improved via BMP/Runx2 pathway. Conclusion: The BPN-DFO hydrogel possesses potential tissue engineer material for ischemic bone defect treatment. However, furthermore studies are needed to testify the safety and efficacy of BPN-DFO hydrogel.

Characterisation of individual ferritin response in patients receiving chelation therapy.

AIMS: To develop a drug-disease model describing iron overload and its effect on ferritin response in patients affected by transfusion-dependent haemoglobinopathies and investigate the contribution of interindividual differences in demographic and clinical factors on chelation therapy with deferiprone or deferasirox. METHODS: Individual and mean serum ferritin data were retrieved from 13 published studies in patients affected by haemoglobinopathies receiving deferiprone or deferasirox. A nonlinear mixed effects modelling approach was used to characterise iron homeostasis and serum ferritin production taking into account annual blood consumption, baseline demographic and clinical characteristics. The effect of chelation therapy was parameterised as an increase in the iron elimination rate. Internal and external validation procedures were used to assess model performance across different study populations. RESULTS: An indirect response model was identified, including baseline ferritin concentrations and annual blood consumption as covariates. The effect of chelation on iron elimination rate was characterised by a linear function, with different slopes for each drug (0.0109 [90% CI: 0.0079-0.0131] vs. 0.0013 [90% CI: 0.0008-0.0018] L/mg mo). In addition to drug-specific differences in the magnitude of the ferritin response, simulation scenarios indicate that ferritin elimination rates depend on ferritin concentrations at baseline. CONCLUSION: Modelling of serum ferritin following chronic blood transfusion enabled the evaluation of drug-induced changes in iron elimination rate and ferritin production. The use of a semi-mechanistic parameterisation allowed us to disentangle disease-specific factors from drug-specific properties. Despite comparable chelation mechanisms, deferiprone appears to have a significantly larger effect on the iron elimination rate than deferasirox.

Effects of dual chelation therapy with deferasirox and deferoxamine in patients with beta thalassaemia major.

BACKGROUND AND OBJECTIVES: Patients with thalassaemia experience complications related to iron overload. In Australia currently, the two main options for iron chelation are deferasirox and deferoxamine. Optimal iron chelation using monotherapy can be limited due to toxicity or tolerability. Dual chelation therapy (DCT) may provide more aggressive iron chelation. MATERIAL AND METHODS: A retrospective, observational study was performed on a state-wide referral centre for patients receiving red cell transfusions for haemoglobinopathies (Monash Health, Australia). All patients prescribed DCT were identified using a local pharmacy dispensing database and were included in the study. Pre-DCT initiation and post-DCT completion were correlated with serum ferritin, cardiac iron loading (based on MRI T2* measurements) and liver iron content (LIC) using Wilcoxon signed-rank test. RESULTS: A total of 18 patients (12 adults, 6 children) were identified as receiving DCT. All patients received a combination of deferasirox and deferoxamine. The median duration of therapy was 23 months (range 2-73). Median serum ferritin reduced by 42% (p = 0.004) and there was a 76% reduction in LIC (p = 0.062). No significant changes were seen in cardiac iron loading. CONCLUSION: DCT over a prolonged period is effective at reducing serum ferritin and may contribute to improvement in liver iron loading.

Protective Effects of Curcumin against Iron-induced Toxicity.

Iron is an essential element in cellular metabolism that participates in many biochemical reactions. Nevertheless, iron overload in the body is the cause of damage in some organs including the liver, glands, brain, heart, gastrointestinal tract and lung. Iron chelation therapy could be considered an effective approach for removing excess iron. Deferoxamine, deferiprone and deferasirox are three common iron chelators in clinical practice but cause several side effects. In this context, the use of curcumin, a dietary phytochemical derived from turmeric, as a natural and safe antioxidant with iron-chelating activity may be a useful strategy for the management of iron overload. This review focuses on the deleterious effect of iron accumulation in different organs of the body as well as the therapeutic potential of curcumin against iron-induced toxicity.

Renal function in ß-thalassemia major patients treated with two different iron-chelation regimes.

BACKGROUND: Renal injury in transfusion dependent ß thalassemia patients (TDT) has been attributed to iron overload, chronic anemia and iron-chelation therapy (ICT) toxicity. We studied renal function in TDT patients treated with two different ICT regimes. PATIENTS AND METHODS: We studied 36 TDT patients: 26 received deferasirox (DFX) and 10 were treated with deferoxamine (DFO) +/- deferiprone (DFP). RESULTS: Increased uNAG was found in 30% of the DFX group vs. 10% of the DFO+/-DFP group, the mean uNAG level in the DFX group was significantly higher than in the DFO+/-DFP group, (P < 0.05). A moderate negative correlation was found between uNAG levels and mean serum ferritin for the prior 10 years (P = 0.03), more pronounced for the DFO+/-DFP group. Twenty nine patients had had their renal function evaluated 10 years earlier; eGFR significantly declined in patients switched to DFX (P = 0.0093) but not in patients who continued DFO+/-DFP. CONCLUSIONS: A high prevalence of renal tubular damage was observed in our TDT patients, particularly those treated with DFX; uNAG was negatively associated with mean 10-year serum ferritin, suggesting ICT's involvement in tubular injury. A significant decline in eGFR compared to a decade earlier was observed only in patients currently treated with DFX. Strict follow-up of renal function in TDT patients is warranted.

Bilateral maculopathy in a thalassemia patient on iron chelation therapy: a case report / Maculopatia bilateral em paciente com talassemia em terapia quelante de ferro: relato de caso

ABSTRACT A 10-year-old Malay girl with underlying HbE/beta-thalassemia, on regular blood transfusion and deferoxamine iron chelation therapy, presented with two-month history of bilateral blurring of vision. On examination, her vision was 6/36 both eyes. Other optic nerve functions were normal. Anterior segment examination of both eyes was unremarkable. Fundus examination of both eyes revealed dull foveal reflex. Optical coherence tomography of both maculae showed increased central subfield thickness. Fundus fluorescence angiography showed patchy hypofluorescence over macular region for both eyes and late staining, indicating retinal pigment epithelium anomalies. A diagnosis of iron-chelation-therapy-related bilateral maculopathy was made. Patient was co-managed with pediatric hematology team to adjust the dose of deferoxamine, and was given three monthly appointments to monitor the progression of maculopathy at the ophthalmology clinic. However patient defaulted ophthalmology follow-up after the first visit.

RESUMO Uma menina malaia de 10 anos de idade com doença de base- B/beta-talassemia, em transfusão de sangue regular e terapia quelante de ferro deferoxamina, apresentou história de dois meses de visão turva bilateral. Ao exame, sua visão era de 6/36 em ambos os olhos. Outras funções do nervo óptico estavam normais. O exame do segmento anterior de ambos os olhos foi normal. Exame do fundo de ambos os olhos revelou reflexo foveal opaco. A tomografia de coerência óptica de ambas as máculas mostrou aumento da espessura do subcampo central. A angiografia de fluorescência do fundo mostrou hipofluorescência irregular sobre a região macular de ambos os olhos e coloração tardia, indicando anomalias de epitélio pigmentar da retina. Um diagnóstico de maculopatia bilateral relacionada à terapia quelante de ferro foi feito. A paciente foi avaliada em conjunto com a equipe de hematologia pediátrica para ajustar a dose de deferoxamina, e foram oferecidas três consultas mensais na clínica oftalmológica, para monitorar a progressão da maculopatia. No entanto, ela não compareceu para acompanhamento oftalmológico após a primeira visita.

Combined chelation with high-dose deferiprone and deferoxamine to improve survival and restore cardiac function effectively in patients with transfusion-dependent thalassemia presenting severe cardiac complications.

Iron overload-induced cardiomyopathy is the leading cause of death in patients with transfusion-dependent thalassemia (TDT). The mortality is extremely high in these patients with severe cardiac complications, and how to rescue them remains a challenge. It is reasonable to use combined chelation with deferiprone (L1) and deferoxamine (DFO) because of their shuttle and synergistic effects on iron chelation. Here, seven consecutive patients with TDT who had severe cardiac complications between 2002 and 2019 and received combined chelation therapy with oral high-dose L1 (100 mg/kg/day) and continuous 24-h DFO infusion (50 mg/kg/day) in our hospital were reported. Survival for eight consecutive patients receiving DFO monotherapy for their severe cardiac complications between 1984 and 2001 was compared. We found that combined chelation therapy with high-dose L1 and DFO was efficient to improve survival and cardiac function in patients with TDT presenting severe cardiac complications. Reversal of arrhythmia to sinus rhythm was noted in all patients. Their 1-month follow-up left ventricular ejection fraction increased significantly (P < 0.001). There were no deaths, and all patients were discharged from hospital with good quality of life. In contrast, all the eight patients receiving DFO monotherapy died (P < 0.001). Accordingly, combined chelation therapy with high-dose L1 and DFO should be considered in patients with TDT presenting cardiac complications.

Reduction of Liver Iron Load in Adult Patients with ß-Thalassemia Major Treated with Modern Chelation Modalities.

BACKGROUND: Management of beta-thalassemia major (TM) requires life-long hemotransfusions leading to iron overload. Iron elimination is enhanced by the use of modern chelators. AIM: To assess the effect of modern chelation therapy by dynamics of serum ferritin concentration and liver MRI T2*. PATIENTS AND METHODS: Forty-six patients with TM (male to female ratio =1:1, mean age 33.2±10.9 years) were prospectively studied between 2011 and 2014. Twenty-one patients (45.7%) were treated with deferasirox, 17 (37%) - with deferiprone, and 8 (17.3%) - with deferiprone in combination with deferoxamine. Ferritin was measured by ELISA. MRI T2* was assessed by Siemens Magnetom Avanto 1.5T. The patients were allocated into 3 groups based on their initial ferritin level and liver MRI T2*. Statistical analysis was performed using SPSS v. 18 for Windows. Data were analysed by descriptive analysis, analysis of variance and correlative analysis, means were compared using t-test and one-way ANOVA. RESULTS: In 2011, 9 (19.5%) patients had normal liver MRI T2*; in 2014 they were 17 (37%). The patients with mild grade liver siderosis were 12 (26%) in 2011, and in 2014 they were 14 (30.4%). In 2011, the patients with moderate liver siderosis were 14 (30.4%), and in 2014 - 12 (26.0%). Eleven patients (23.9%) had severe liver siderosis in 2011 and only two patients (4.0%) were diagnosed with the condition in 2014. CONCLUSION: A reduction of iron overload was found in all studied groups. This positive effect is attributed to the use of modern chelators and the ease of access to accurate monitoring.

Development of Neutropenic Murine Models of Iron Overload and Depletion To Study the Efficacy of Siderophore-Antibiotic Conjugates.

Siderophore-antibiotic conjugates have increased in vitro activity in low-iron environments where bacteria express siderophores and associated transporters. The host immune hypoferremic response reduces iron availability to bacteria; however, patients with iron overload or deficiency may have altered ability to restrict iron, which may affect the efficacy of siderophore-antibiotic conjugates. In vivo models of infection with iron overload and deficiency are needed to perform this assessment. The standard neutropenic murine thigh infection model was supplemented with iron-altering treatments: iron dextran at 100 mg/kg of body weight daily for 14 days to load iron or deferoxamine at 100 mg/kg daily plus a low-iron diet for up to 30 days to deplete iron. Human-simulated regimens of cefiderocol and meropenem were administered in both models to assess any impact of iron alteration on plasma pharmacokinetics. Median iron in overloaded mice was significantly higher than that of controls in plasma (1,657 versus 336 µg/dl; P < 0.001), liver (2,133 versus 11 µg/g; P < 0.001), and spleen (473 versus 144 µg/g; P < 0.001). At 30 days, depleted mice had significantly lower iron than controls in liver (2.4 versus 6.5 µg/g; P < 0.001) and spleen (72 versus 133 µg/g; P = 0.029) but not plasma (351 versus 324 µg/dl; P = 0.95). Cefiderocol and meropenem plasma concentrations were similar in iron overloaded and control mice but varied in iron-depleted mice. The iron-overloaded murine thigh infection model was established, and human-simulated regimens of cefiderocol and meropenem were validated therein. While deferoxamine successfully reduced liver and splenic iron, this depleting treatment altered the pharmacokinetics of both antimicrobials.