Nanosponge for Iron Chelation and Efflux: A Ferroptosis-Inhibiting Approach for Myocardial Infarction Therapy

Myocardial infarction (MI), a consequence of coronary artery occlusion, triggers the degradation of ferritin, resulting in elevated levels of free iron in the heart and thereby inducing ferroptosis. Targeting myocardial ferroptosis through the chelation of excess iron has therapeutic potential for MI treatment. However, iron chelation in post ischemic injury areas using conventional iron-specific chelators is hindered by ineffective myocardial intracellular chelation, rapid clearance, and high systemic toxicity. A chitosan-desferrioxamine nanosponge (CDNS) is designed by co-crosslinking chitosan and deferoxamine through noncovalent gelation to address these challenges. This architecture facilitates direct iron chelation regardless of deferoxamine (DFO) release due to its sponge-like porous hydrogel structure. Upon cellular internalization, CDNS can effectively chelate cellular iron and facilitate the efflux of captured iron, thereby inhibiting ferroptosis and associated oxidative stress and lipid peroxidation. In MI mouse models, myocardial injection of CDNS promotes sustainable retention and the suppression of ferroptosis in the infarcted heart. This intervention improves cardiac function and alleviates adverse cardiac remodeling post-MI, leading to decreased oxidative stress and the promotion of angiogenesis due to ferroptosis inhibition by CDNS in the infarcted heart. This study reveals a nanosponge-based nanomedicine targeting myocardial ferroptosis with efficient iron chelation and efflux, offering a promising MI treatment.

Deferoxamine-Loaded Chitosan-Based Hydrogel on Bone Implants Showing Enhanced Bond Strength and Pro-Angiogenic Effects

Angiogenesis is vital for bone fracture healing and plays a significant role in the fate of orthopedic implants. The growth and maintenance of new blood vessels at the fracture site of patients is essential, which promotes the clinical outcome of plasma sprayed Ti (PST) coated orthopedic implants. In order to endow the PST coating with pro-angiogenic effects, deferoxamine-loaded chitosan-based hydrogel was fabricated on the coating surface. Polydopamine-modified chitosan (CS/PDA) hydrogel exhibited enhanced bonding strength to PST coatings as evidenced by scratch test. The deferoxamine-loaded CS/PDA (CS/PDA-DFO) exhibited a sustained drug-release property, and the cumulative concentration of released DFO reached 20.21 μg/mL on day 7. PST-CS/PDA with higher wettability and active group quantity enhanced the viability and adhesion characteristics of human umbilical vein endothelial cells (HUVECs) and upregulated the secretion level of nitric oxide and vascular endothelial growth factor. Moreover, the introduction of DFO in PST-CS/PDA further enhanced the pro-angiogenic effects. Above all, this study offers a novel approach for developing hydrogel coating on orthopedic implants showing enhanced bonding strength and pro-angiogenic effects.

Bile Acid-Targeted Hyaluronic Acid Nanoparticles for Enhanced Oral Absorption of Deferoxamine

Patients with β-thalassemia and sickle cell disease often rely on blood transfusions which can lead to hemochromatosis and chronic oxidative stress in cells and tissues. Deferoxamine (DFO) is clinically approved to treat hemochromatosis but is suboptimal to patients due to its poor pharmacokinetics which requires long-term infusion regimens. Although the oral route is preferable, DFO has limited oral bioavailability. Studies have shown that hyaluronic acid (HA) and bile acid (BA) can enhance the oral absorption of poorly absorbed drugs. To improve upon the oral delivery of DFO, we report on the synthesis and characterization of HA (MW 15 kD) conjugated to two types of BA, deoxycholic acid (DOCA) and taurocholic acid (TCA), and DFO. The resulting seven polymeric conjugates all formed self-assembled nanoparticles. The degree of BA and DFO conjugation to the HA polymer was confirmed at each step through nuclear magnetic resonance, Fourier transform infrared spectroscopy, and UV-Vis spectroscopy. The best formulations for further in vitro testing were determined based on physicochemical characterizations and included HA-DFO, TCA9-HA-DFO, and DOCA9-HA-DFO. Results from in vitro assays revealed that TCA9-HA-DFO enhanced the permeation of DFO the most and was also less cytotoxic to cells compared to the free drug DFO. In addition, ferritin reduction studies indicated that the conjugation of DFO to TCA9-HA did not compromise its chelation efficiency at equivalent free DFO concentrations. This research provides supportive data for the idea that TCA conjugated to HA may enhance the oral absorption of DFO, improve its cytocompatibility, and maintain its iron chelation efficiency.

Iron deficiency in astrocytes alters cellular status and impacts on oligodendrocyte differentiation

Iron deficiency (ID) has been shown to affect central nervous system (CNS) development and induce hypomyelination. Previous work from our laboratory in a gestational ID model showed that both oligodendrocyte (OLG) and astrocyte (AST) maturation was impaired. To explore the contribution of AST iron to the myelination process, we generated an in vitro ID model by silencing divalent metal transporter 1 (DMT1) in AST (siDMT1 AST) or treating AST with Fe3+ chelator deferoxamine (DFX; DFX AST). siDMT1 AST showed no changes in proliferation but remained immature. Co-cultures of oligodendrocyte precursors cells (OPC) with siDMT1 AST and OPC cultures incubated with siDMT1 AST-conditioned media (ACM) rendered a reduction in OPC maturation. These findings correlated with a decrease in the expression of AST-secreted factors IGF-1, NRG-1, and LIF, known to promote OPC differentiation. siDMT1 AST also displayed increased mitochondrial number and reduced mitochondrial size as compared to control cells. DFX AST also remained immature and DFX AST-conditioned media also hampered OPC maturation in culture, in keeping with a decrease in the expression of AST-secreted growth factors IGF-1, NRG-1, LIF, and CNTF. DFX AST mitochondrial morphology and number showed results similar to those observed in siDMT1 AST. In sum, our results show that ID, induced through two different methods, impacts AST maturation and mitochondrial functioning, which in turn hampers OPC differentiation.

Multimodal imaging in deferasirox-mediated retinopathy

INTRODUCTION

Deferasirox is the only iron chelator available in oral formulation and a rare cause of pigmentary retinopathy. We report the first case of multimodal imaging in an adult with deferasirox retinopathy.

METHODS

Case report and literature review, with search terms including deferasirox retinopathy and deferasirox toxicity.

RESULTS

A 63-year-old man with end stage renal disease and transfusion-dependent anemia on deferasirox for one year presented with asymptomatic pigment epitheliopathy. Optical coherence tomography featured outer retinal and retinal pigment epithelial discontinuity corresponding to hypoautofluorescence on fundus autofluorescence and blocking on fluorescein angiography. Multifocal electroretinography revealed subtle reduction in all amplitudes.

CONCLUSIONS

Retinal examinations should be considered for patients requiring chronic administration of deferasirox.

Deferoxamine topical cream superior to patch in rescuing radiation-induced fibrosis of unwounded and wounded skin

Topical patch delivery of deferoxamine (DFO) has been studied as a treatment for this fibrotic transformation in irradiated tissue. Efficacy of a novel cream formulation of DFO was studied as a RIF therapeutic in unwounded and excisionally wounded irradiated skin. C57BL/6J mice underwent 30 Gy of radiation to the dorsum followed by 4 weeks of recovery. In a first experiment, mice were separated into six conditions: DFO 50 mg cream (D50), DFO 100 mg cream (D100), soluble DFO injections (DI), DFO 1 mg patch (DP), control cream (Vehicle), and irradiated untreated skin (IR). In a second experiment, excisional wounds were created on the irradiated dorsum of mice and then divided into four treatment groups: DFO 100 mg Cream (W-D100), DFO 1 mg patch (W-DP), control cream (W-Vehicle), and irradiated untreated wounds (W-IR). Laser Doppler perfusion scans, biomechanical testing, and histological analysis were performed. In irradiated skin, D100 improved perfusion compared to D50 or DP. Both D100 and DP enhanced dermal characteristics, including thickness, collagen density and 8-isoprostane staining compared to untreated irradiated skin. D100 outperformed DP in CD31 staining, indicating higher vascular density. Extracellular matrix features of D100 and DP resembled normal skin more closely than DI or control. In radiated excisional wounds, D100 facilitated faster wound healing and increased perfusion compared to DP. The 100 mg DFO cream formulation rescued RIF of unwounded irradiated skin and improved excisional wound healing in murine skin relative to patch delivery of DFO.

Biomimetic Hydrogel Containing Copper Sulfide Nanoparticles and Deferoxamine for Photothermal Therapy of Infected Diabetic Wounds

Inducing cell migration from the edges to the center of a wound, promoting angiogenesis, and controlling bacterial infection are very important for diabetic wound healing. Incorporating growth factors and antibiotics into hydrogels for wound dressing is considered a potential strategy to meet these requirements. However, some present drawbacks greatly slow down their development toward application, such as the short half-life and high price of growth factors, low antibiotic efficiency against drug-resistant bacteria, insufficient ability of hydrogels to promote cell migration, etc. Deferoxamine (DFO) can upregulate the expression of HIF-1α, thus stimulating the secretion of angiogenesis-related endogenous growth factors. Copper sulfide (CuS) nanoparticles possess excellent antibacterial performance combined with photothermal therapy (PTT). Herein, DFO and CuS nanoparticles are incorporated into a biomimetic hydrogel, which mimics the structure and function of the extracellular matrix (ECM), abbreviated as DFO/CuS-ECMgel. This biomimetic hydrogel is expected to be able to promote cell adhesion and migration, be degraded by cell-secreted matrix metalloproteinases (MMPs), and then release DFO and CuS nanoparticles at the wound site to exert their therapeutic effects. As a result, the three crucial requirements for diabetic wound healing, "beneficial for cell adhesion and migration, promoting angiogenesis, effectively killing drug-resistant bacteria," can be achieved simultaneously.

Hierarchical Composite Scaffold with Deferoxamine Delivery System to Promote Bone Regeneration via Optimizing Angiogenesis

A bone defect refers to the loss of bone tissue caused by trauma or lesions. Bone defects result in high morbidity and deformity rates worldwide. Autologous bone grafting has been widely applied in clinics as the gold standard of treatment; however, it has limitations. Hence, bone tissue engineering (BTE) has been proposed and developed as a novel therapeutic strategy for treating bone defects. Rapid and effective vascularization is essential for bone regeneration. In this study, a hierarchical composite scaffold with deferoxamine (DFO) delivery system, DFO@GMs-pDA/PCL-HNTs (DGPN), was developed, focusing on vascularized bone regeneration. The hierarchical structure of DGPN imitates the microstructure of natural bone and interacts with the local extracellular matrix (ECM), facilitating cell adhesion and proliferation. The addition of 1 wt% of halloysite nanotubes (HNTs) improved the material properties. Hydrophilic and functional groups conferred by polydopamine (pDA) modifications strengthened the scaffold bioactivity. Gelatin microspheres (GMs) protected the pharmacological activity of DFO, achieving local application and sustained release for seven days. DFO effectively promoted angiogenesis by activating the signaling pathway of hypoxia inducible factor-1 α (HIF-1 α). In addition, DFO synergized with HNTs to promote osteogenic differentiation and matrix mineralization. These results indicated that DGPN promoted bone regeneration and accelerated cranial defect healing. This article is protected by copyright. All rights reserved.

Compare the Efficacy and Safety of Deferoxamine, Deferasirox, and Deferiprone in Patients With Sickle Cell Disease or Transfusion-Dependent Anemia: A Network Meta-Analysis of Randomized Control Trials

This network meta-analysis was conducted with the aim of comparing the efficacy and safety of deferiprone (DFP), deferasirox (DFX), and deferoxamine (DFO) in individuals with sickle cell disease (SCD) or transfusion-dependent anemia. This systematic review and meta-analysis adhered to the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)" guidelines. The search was conducted on electronic databases, including PubMed, CINAHIL, and EMBASE, from the inception of databases to January 10, 2024. Outcomes assessed in this study included a change in liver iron concentration (LIC) and a change in ferritin from baseline. For safety analysis, adverse events were compared among three treatment groups. A total of five studies were included in this meta-analysis. The pooled analysis showed that the change in LIC and serum ferritin from baseline was not significantly different in patients with SCD or other anemias. In terms of adverse events, deferiprone was the safest among all. In conclusion, deferiprone demonstrated noninferiority to deferoxamine and deferasirox in measures of iron load, presenting a viable treatment option. Safety outcomes revealed deferasirox carried a higher risk of adverse events compared to deferiprone, supporting its favorable safety profile.

Agar and Chitosan Hydrogels' Design for Metal-Uptaking Treatments

In the field of cultural heritage, the use of natural gels is rising for the application of active agents. Here, two natural polymers are assessed: agar, a pioneer hydrogel for conservation treatments, and chitosan, a rather novel and metal-binding gel. For chitosan, a state-of-the-art based formulation (CS-ItA-LCys) is evaluated as it was reported for silver-complexing properties. It is evaluated whether these polymers can withstand the addition of the chelating compound deferoxamine, which is a bacterial siderophore. This allows for the obtainment of completely bio-sourced gel systems. A Fourier-transformed (FT) infrared spectroscopy characterization is performed, completed with rheological measurements and Cryo-Scanning Electron Microscopy (cryo-SEM) to investigate the physico-chemical properties of the gels, as well as their interaction with deferoxamine. Both polymers are also tested for their inherent complexing ability on silver ions using FT-Raman spectroscopy. A multi-analytical comparison shows different microstructures, in particular, the presence of a thick membrane for chitosan and different mechanical behaviors, with agar being more brittle. Neither hydrogel seems affected by the addition of deferoxamine; this is shown by similar rheological behavior and molecular structures in the presence or absence of the chelator. The intrinsic abilities of the chitosan formulation to make silver complex are demonstrated with the observation of two peaks characteristic of Ag-S and Ag-O bonds. Agar and chitosan are both proven to be reliable gels to act as carriers for bio-based active agents. This paper confirms the potential asset of the chitosan formulation CS-ItA-LCys as a promising gel for the complexation of soluble silver.

A Water-Soluble Chitosan Derivative for the Release of Bioactive Deferoxamine

Deferoxamine (DFO) is a water-soluble iron chelator used pharmacologically for the management of patients with transfusional iron overload. However, DFO is not cell-permeable and has a short plasma half-life, which necessitates lengthy parenteral administration with an infusion pump. We previously reported the synthesis of chitosan (CS) nanoparticles for sustained slow release of DFO. In the present study, we developed solid dispersions and nanoparticles of a carboxymethyl water-soluble chitosan derivative (CMCS) for improved DFO encapsulation and release. CS dispersions and nanoparticles with DFO have been prepared by ironical gelation using sodium triphosphate (TPP) and were examined for comparison purposes. The successful presence of DFO in CMCS polymeric dispersions and nanoparticles was confirmed through FTIR measurements. Furthermore, the formation of CMCS nanoparticles led to inclusion of DFO in an amorphous state, while dispersion of DFO in the polymeric matrix led to a decrease in its crystallinity according to X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results. An in vitro release assay indicated sustained release of DFO from CS and CMCS nanoparticles over 48 h and 24 h, respectively. Application of CMCS-DFO dispersions to murine RAW 264.7 macrophages or human HeLa cervical carcinoma cells triggered cellular responses to iron deficiency. These were exemplified in the induction of the mRNA encoding transferrin receptor 1, the major iron uptake protein, and the suppression of ferritin, the iron storage protein. Our data indicate that CMCS-DFO nanoparticles release bioactive DFO that causes effective iron chelation in cultured cells.

Deferiprone versus deferoxamine for transfusional iron overload in sickle cell disease and other anemias: Pediatric subgroup analysis of the randomized, open-label FIRST study

BACKGROUND

Children with sickle cell disease (SCD) who are chronically transfused often, require iron chelation therapy. There are limited data that allow for comparison of the efficacy and safety of the iron chelator deferiprone versus deferoxamine in children with SCD.

METHODS

This post hoc analysis of the phase 3b/4, randomized, open-label FIRST (Ferriprox in Patients with IRon Overload in Sickle Cell Disease Trial) study (NCT02041299) included patients 17 years and younger with SCD or other anemias receiving deferiprone or deferoxamine.

RESULTS

Overall, 142 patients were evaluated; mean ages were 10.5 and 11.7 years in the deferiprone and deferoxamine groups, respectively. At 12 months: mean change from baseline in liver iron concentration was -3.3 mg/g dry weight (dw) with deferiprone and -3.4 mg/g dw with deferoxamine (p = .8216); relative mean change (coefficient of variation %) in log cardiac T2* magnetic resonance imaging was 1.02 (21.8%) with deferiprone and 0.95 (19.5%) with deferoxamine (p = .0717); and the mean (standard error) change in serum ferritin levels was -133.0 (200.3) μg/L with deferiprone and -467.1 (244.1) μg/L with deferoxamine (p = .2924). The most common deferiprone-related adverse events (AEs) were upper abdominal pain (20.2%), vomiting (13.8%), pyrexia (9.6%), decreased neutrophil count (9.6%), increased alanine aminotransferase (ALT; 9.6%), and increased aspartate aminotransferase (AST; 9.6%). All cases of increased ALT, increased AST, and neutropenia resolved, most without intervention.

CONCLUSIONS

This post hoc analysis of pediatric patients from FIRST corroborated previous findings in adults that deferiprone is comparable to deferoxamine in reducing iron overload. No new safety concerns were observed. Deferiprone is an oral chelation option that could improve adherence and outcomes in children.

Liver Dysfunction with Severe Cholestasis and Coagulation Disorders in the Course of Hemolytic Disease of the Newborn Requiring Chelation Therapy-A Case Report and Review of the Literature

Severe hemolytic disease of the fetus and newborn (HDFN) requiring intrauterine transfusions (IUTs) may cause iron accumulation, resulting in liver damage, which may lead to cholestasis and coagulation disorders. In this article, we reported a case of a female neonate who underwent chelation therapy with a positive outcome, and we reviewed the English and Polish literature on chelation therapy in HDFN available in PubMed. The patient with maximum ferritin concentration above 33,511.2 ng/mL developed liver dysfunction with coagulation disorders requiring multiple transfusions of fresh frozen plasma (FFP), Octaplex® and cryoprecipitate, and hypoalbuminemia treated with numerous albumin infusions. Furthermore, severe cholestasis was observed with direct bilirubin levels up to 33.14 mg/dL. Additionally, the child developed transient myelosuppression with neutropenia, thrombocytopenia, and low reticulocyte count due to several blood transfusions. The differential diagnosis tests were conducted to rule out any causes of hepatic failure other than hemolytic disease of the newborn. This case proves that adequate treatment of severe HDFN with anemia requiring IUT and hepatic failure can lead to positive outcomes with no long-term consequences.

Depletion of Labile Iron Induces Replication Stress and Enhances Responses to Chemoradiation in Non-Small-Cell Lung Cancer

The intracellular redox-active labile iron pool (LIP) is weakly chelated and available for integration into the iron metalloproteins that are involved in diverse cellular processes, including cancer cell-specific metabolic oxidative stress. Abnormal iron metabolism and elevated LIP levels are linked to the poor survival of lung cancer patients, yet the underlying mechanisms remain unclear. Depletion of the LIP in non-small-cell lung cancer cell lines using the doxycycline-inducible overexpression of the ferritin heavy chain (Ft-H) (H1299 and H292), or treatment with deferoxamine (DFO) (H1299 and A549), inhibited cell growth and decreased clonogenic survival. The Ft-H overexpression-induced inhibition of H1299 and H292 cell growth was also accompanied by a significant delay in transit through the S-phase. In addition, both Ft-H overexpression and DFO in H1299 resulted in increased single- and double-strand DNA breaks, supporting the involvement of replication stress in the response to LIP depletion. The Ft-H and DFO treatment also sensitized H1299 to VE-821, an inhibitor of ataxia telangiectasis and Rad2-related (ATR) kinase, highlighting the potential of LIP depletion, combined with DNA damage response modifiers, to alter lung cancer cell responses. In contrast, only DFO treatment effectively reduced the LIP, clonogenic survival, cell growth, and sensitivity to VE-821 in A549 non-small-cell lung cancer cells. Importantly, the Ft-H and DFO sensitized both H1299 and A549 to chemoradiation in vitro, and Ft-H overexpression increased the efficacy of chemoradiation in vivo in H1299. These results support the hypothesis that the depletion of the LIP can induce genomic instability, cell death, and potentiate therapeutic responses to chemoradiation in NSCLC.

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.

Topical Iron Chelator Therapy: Current Status and Future Prospects

Systemic iron chelation therapy has long been used for iron overload, providing a role in returning iron levels to proper homeostatic concentrations. Recently, topical iron chelation therapy has emerged as a potential strategy for treating skin damage. This narrative review explores the current status and future prospects of topical iron chelation therapy for treating ultraviolet (UV) and non-UV skin damage, as well as its potential application in wound healing. The review was conducted through a literature search across PubMed, Web of Science, and EMBASE databases, spanning publications from 1990 to 2023. The selection of articles was focused on primary research studies, either experimental or clinical, that explored the implications and formulations of topical iron chelators used alone or in conjunction with another therapeutic agent. The search strategy employed a combination of terms, including "topical iron chelation", "topical deferoxamine", "UV", "wound healing", "skin inflammation", "radiation-induced fibrosis", and "skin cancer". Relevant studies, including methods, intervention strategies, measured outcomes, and findings, are summarized. The review also considered the potential challenges in translating research findings into clinical practice. Results indicate that topical iron chelators, such as deferoxamine, are effective in mitigating UV-induced skin damage, reducing tumorigenesis, and decreasing oxidative damage. In addition, the use of these agents in radiation-induced fibrosis has been shown to significantly increase skin elasticity and reduce dermal fibrosis. Several studies also highlight the use of topical iron chelators in difficult-to-treat chronic wounds, such as diabetic neuropathic ulcers and sickle cell ulcers. In conclusion, topical iron chelation therapy represents a novel and promising approach for skin protection and wound healing. Its potential makes it a promising area of future research.

[Deferoxamine promotes recovery of bone marrow hematopoietic function in mice exposed to a sublethal dose of X-ray irradiation]

OBJECTIVE

To evaluate the effect of deferoxamine (DFO) on bone marrow hematopoietic function in C57 mice exposed to a sublethal dose of X-ray irradiation.

METHODS

C57 mice exposed to a sublethal dose (5.4 Gy, 1.0 Gy/min) of total body X-ray irradiation (TBI) were treated with subcutaneous injection of 100 mg/kg DFO, with normal saline as the control, on a daily basis for 10 and 20 consecutive days. Body weight changes of the mice were monitored every 3 days. Five mice were selected from each group at 10 and 20 days for examination of blood cell counts, bone marrow nucleated cell counts, percentage of bone marrow CD34+ cells, bone marrow pathology, and expressions of cleaved PARP-1, cleaved caspase-3, VEGF, GPX4, and SLC7A11 in the nucleated cells.

RESULTS

The body weight of the mice decreased significantly on day 3 in TBI and DFO groups (P<0.05), and to the lowest on day 6 in TBI group (P<0.01). Blood cell counts and bone marrow nucleated cell counts of the mice were significantly decreased at 10 and 20 days following TBI (P<0.01). On day 10 following TBI, the mice showed significantly decreased nucleated cells and the presence of adipocytes in the bone marrow, where increased expressions of cleaved PARP-1 and cleaved caspase-3 and lowered expressions of GPX4 and SLC7A11 were detected in the nucleated cells (P<0.05). In the mice exposed to TBI, treatment with DFO significantly increased CD34+ cell percentage (P<0.001), decreased the expressions of cleaved PARP-1 and cleaved caspase-3, and increased the expressions of GPX4, SLC7A11 and VEGF in the bone marrow nucleated cells (P<0.05). DFO treatment significantly increased blood cell counts and bone marrow nucleated cells in mice at 20 days following TBI (P<0.05).

CONCLUSION

DFO improves bone marrow hematopoiesis in mice with sublethal-dose TBI by inhibiting apoptosis and ferroptosis of bone marrow nucleated cells and promoting VEGF expression and CD34+ cell proliferation.

Vectorization via Siderophores Increases Antibacterial Activity of K(RW)3 Peptides against Pseudomonas aeruginosa

A series of new conjugates comprised from a small synthetic antimicrobial peptide (AMP) and a siderophore-type vector component was designed and tested for activity on P. aeruginosa PAO1 and several genetically modified strains. As AMP, the well-established arginine-tryptophane combination K(RW)3 (P1) was chosen with an added lysine for siderophore attachment. This peptide is easy to prepare, modify, and possesses good anti-bacterial activity. On the vector part, we examined several moieties: (i) the natural siderophore deferoxamine (DFO); (ii) bidentate iron chelators based on the hydroxamate building block (4 a-c) ; (iii) the non-siderophore chelators deferasirox (DFX) and deferiprone-carboxylate (DFP-COOH). All conjugates were prepared by solid phase synthesis techniques and fully characterized by HPLC and mass spectrometry (including HR-MS). 55 Fe uptake assays indicate a receptor-mediated uptake for 4 a-c, DFP-COOH and DFO, which is dependent on the outer membrane transporter FoxA in the case of DFO. All conjugates showed increased antibacterial activity against P. aeruginosa compared to the parent peptide P1 alone when investigated in iron-depleted medium. MIC values were as low as 2 μM (for P1-DFP) on wild type P. aeruginosa. The activity of P1-DFO and P1-DFP was even better on genetically mutated strains unable to produce siderophores (down to 0.5 μM). Although the DFX vector on its own was not able to transport iron inside the bacterial cell as shown by 55 Fe uptake studies, the P1-DFX conjugate had excellent antibacterial activity compared to P1 (2 μM, and as low as 0.25 μM on a receptor-deficient strain unable to produce siderophores), suggesting that the conjugates were indeed recognized and internalized by an (unknown) transporter. Control experiments with an equimolar mixture of P1 and DFX confirm that the observed activity is intrinsic to vectorization. This work thus demonstrates the power of linking small AMPs covalently to siderophores for a new class of Trojan Horse antibiotics, with P1-DFP and P1-DFX being the most potent conjugates.

Effects of deferoxamine on intrinsic colistin resistance of Proteus mirabilis

Proteus mirabilis is a common pathogen, which is responsible for urinary tract infections. Iron is a critical element necessary for both humans and pathogens to maintain their biological functions, and iron limitation via chelator agents may be useful in the treatment of infections. The present study aimed to investigate the synergistic interactions between the iron chelator agent deferoxamine (DFO) and the antibacterial drug colistin. The minimum inhibitory concentration (MIC) values of DFO and colistin for P. mirabilis isolates were determined by broth microdilution. The checkerboard technique was used to examine the potential synergy between DFO and colistin. Furthermore, time-kill assays were used for the confirmation of synergy detected by the checkerboard assay, as well as for determining bacteriostatic and bactericidal interactions throughout a 24-h period. As expected, all P. mirabilis isolates were resistant to colistin. DFO did not inhibit P. mirabilis growth when used alone, even at very high doses (10 µg ml-1). Notably, when in combination with DFO, the MIC values of colistin were markedly reduced, and the checkerboard assay results showed synergy between colistin and DFO for all isolates. In addition, in time-kill assays, colistin + DFO exhibited synergistic activity against all strains at most time intervals and concentrations tested. Colistin + DFO showed bactericidal activity at colistin concentrations of 1xMIC and 2xMIC, although a degree of re-growth was observed in one of the strains at 12-24 h. These findings indicated that DFO has the potential for use as an adjunct to colistin through iron sequestration, thus providing synergistic activity to an antibiotic that would not normally be considered a treatment option against P. mirabilis. In vivo experiments in the future may provide useful information on the efficacy of DFO/colistin since these models effectively reflect physiological parameters.

In vitro effects of deferoxamine on antibiotic susceptibility in Gram-negative bacteria

BACKGROUND

Iron is a vital element for the growth of bacteria. Bacteria use several strategies to scavenge iron, such as siderophores, which are thought to be important virulence components. The mammalian host uses various iron-binding substances to make iron unavailable for bacterial uptake. Deferoxamine (DFO) is a semi-synthetic iron chelator that has been licensed for medical use. Iron chelators like DFO may provide an alternative therapeutic technique for treating Gram-negative bacteria infections, which frequently display multidrug resistance.

OBJECTIVES

We assumed that iron deprivation or interactions with the cell membrane caused by DFO or increased siderophore synthesis may cause the inhibition or inactivation of proteins and enzymes necessary for critical processes in bacteria. Additionally, we proposed that these bacterial alterations might be the origin of synergistic interactions between DFO and several antibiotics.

MATERIAL AND METHODS

To test this hypothesis, we used disc diffusion, broth microdilution and checkerboard synergy testing methods on combinations of DFO with ceftriaxone, cefepime, meropenem, amikacin, levofloxacin, and tigecycline, respectively, in a total of 55 isolates (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Proteus mirabilis strains - 11 isolates for each genus).

RESULTS

No synergistic or antagonistic interactions were observed between DFO and the tested antibiotics in the E. coli, K. pneumoniae, P. aeruginosa, and A. baumannii isolates, while the addition of DFO significantly increased the inhibition zone diameters of cefepime, amikacin, meropenem, tigecycline, and levofloxacin in P. mirabilis isolates. According to the checkerboard synergy results, a synergistic interaction was found between DFO and tigecycline, cefepime and amikacin for P. mirabilis isolates.

CONCLUSIONS

Among the investigated bacteria, a synergy between antibiotics and DFO was only discovered against P. mirabilis. We do not believe that this entirely disproves our hypothesis, though. The production of siderophores triggered by the increased metabolic activity of actively proliferating bacteria at the infection site may provide better results. Therefore, expanding these investigations and developing infection models through animal testing would be advantageous.

Iron Chelator Deferoxamine Alleviates Progression of Diabetic Nephropathy by Relieving Inflammation and Fibrosis in Rats

Diabetic nephropathy (DN) is one of the most devastating diabetic microvascular complications. It has previously been observed that iron metabolism levels are abnormal in diabetic patients. However, the mechanism by which iron metabolism levels affect DN is poorly understood. This study was designed to evaluate the role of iron-chelator deferoxamine (DFO) in the improvement of DN. Here, we established a DN rat model induced by diets high in carbohydrates and fat and streptozotocin (STZ) injection. Our data demonstrated that DFO treatment for three weeks greatly attenuated renal dysfunction as evidenced by decreased levels of urinary albumin, blood urea nitrogen, and serum creatinine, which were elevated in DN rats. Histopathological observations showed that DFO treatment improved the renal structures of DN rats and preserved podocyte integrity by preventing the decrease of transcripts of nephrin and podocin. In addition, DFO treatment reduced the overexpression of fibronectin 1, collagen I, IL-1β, NF-κB, and MCP-1 in DN rats, as well as inflammatory cell infiltrates and collagenous fibrosis. Taken together, our findings unveiled that iron chelation via DFO injection had a protective impact on DN by alleviating inflammation and fibrosis, and that it could be a potential therapeutic strategy for DN.

Advances in Hypoxia-Inducible Factor-1α Stabilizer Deferoxamine in Tissue Engineering

Deferoxamine (DFO) is an iron chelator with FDA approval for the clinical treatment of iron excess. As a well-established stabilizer of hypoxia-inducible factor-1α (HIF-1α), DFO can efficiently upregulate HIF-1α and relevant downstream angiogenic factors, leading to accelerated vascularization. Moreover, as increasing studies have focused on DFO as a hypoxia-mimetic agent in recent years, it has been shown that DFO exhibited multiple functions, including stem cell regulation, immunoregulation, provascularization, and pro-osteogenesis. On the contrary, DFO can bind excess iron ions in wounds of chronic inflammation, while serving as an antioxidant with the characteristic of removing reactive oxygen species. Collectively, these characteristics make DFO a potent modulator in tissue engineering for increasing tissue integration of biomaterials in vivo and facilitating wound healing. This review outlines the activity of DFO as a representative hypoxia-mimetic agent in cells as well as the evolution of its application in tissue engineering. It can be concluded that DFO is a medication with tremendous promise and application value in future trends, which can optimize biomaterials and existing tissue engineering techniques for tissue regeneration.

Inflammatory Bowel Disease-Associated Colorectal Cancer: Translational and Transformational Risks Posed by Exogenous Free Hemoglobin Alpha Chain, A By-Product of Extravasated Erythrocyte Macrophage Erythrophagocytosis

Colonic inflammatory bowel disease (IBD) encompasses ulcerative colitis (UC) and Crohn's colitis (CC). Patients with IBD are at increased risk for colitis-associated colorectal cancer (CACRC) compared to the general population. CACRC is preceded by IBD, characterized by highly heterogenous, pharmacologically incurable, pertinacious, worsening, and immune-mediated inflammatory pathologies of the colon and rectum. The molecular and immunological basis of CACRC is highly correlated with the duration and severity of inflammation, which is influenced by the exogenous free hemoglobin alpha chain (HbαC), a byproduct of infiltrating immune cells; extravasated erythrocytes; and macrophage erythrophagocytosis. The exogenous free HbαC prompts oxygen free radical-arbitrated DNA damage (DNAD) through increased cellular reactive oxygen species (ROS), which is exacerbated by decreased tissue antioxidant defenses. Mitigation of the Fenton Reaction via pharmaceutical therapy would attenuate ROS, promote apoptosis and DNAD repair, and subsequently prevent the incidence of CACRC. Three pharmaceutical options that attenuate hemoglobin toxicity include haptoglobin, deferoxamine, and flavonoids (vitamins C/E). Haptoglobin's clearance rate from plasma is inversely correlated with its size; the smaller the size, the faster the clearance. Thus, the administration of Hp1-1 may prove to be beneficial. Further, deferoxamine's hydrophilic structure limits its ability to cross cell membranes. Finally, the effectiveness of flavonoids, natural herb antioxidants, is associated with the high reactivity of hydroxyl substituents. Multiple analyses are currently underway to assess the clinical context of CACRC and outline the molecular basis of HbαC-induced ROS pathogenesis by exposing colonocytes and/or colonoids to HbαC. The molecular immunopathogenesis pathways of CACRC herein reviewed are broadly still not well understood. Therefore, this timely review outlines the molecular and immunological basis of disease pathogenesis and pharmaceutical intervention as a protective measure for CACRC.

Ingestion of Toxic Iron Dose With Benign Outcome

Iron poisoning is a significant and potentially life-threatening condition that is commonly encountered in the emergency department. The severity of toxicity is based on the amount of iron ingested, and symptoms can range from mild gastrointestinal discomfort to multi-organ failure. Although current guidelines recommend therapy for patients with estimated ingestion of >60 mg/kg, the most useful laboratory test to determine toxicity is the serum iron level measured at four to six hours after ingestion. In this report, we present a case of a 28-year-old female who ingested a toxic dose of iron (88 mg/kg) but was only minimally symptomatic and managed with supportive care alone. The case highlights the importance of a high index of suspicion, careful clinical evaluation in patients with iron toxicity, and the need for individualized treatment decisions based on the patient's clinical presentation and laboratory values.

Corrigendum: Deferoxamine alleviates osteoarthritis by inhibiting chondrocyte ferroptosis and activating the Nrf2 pathway

[This corrects the article DOI: 10.3389/fphar.2022.791376.].

Deferoxamine in the management of COVID-19 adult patients admitted to ICU: a prospective observational cohort study

COVID-19 infection is associated with high mortality, and despite extensive studying the scientific society is still working to find a definitive treatment. Some experts postulated a beneficial role of Deferoxamine.

Aim

The aim of this study was to compare the outcomes of COVID-19 adult patients admitted to the ICU who received deferoxamine to those who received standard of care.

Methods

Prospective observational cohort study, in the ICU of a tertiary referral hospital in Saudi Arabia to compare all-cause hospital mortality between COVID-19 patients who received deferoxamine and standard of care.

Results

A total of 205 patients were enrolled, with an average age of 50.1±14.3, 150 patients received standard of care only, and 55 patients received deferoxamine additionally. Hospital mortality was lower in deferoxamine group (25.5 vs. 40.7%, 95% CI=1.3-29.2%; P=0.045). Clinical status score upon discharge was lower in deferoxamine group (3.6±4.3 vs. 6.2±4, 95% CI: 1.4-3.9; P<0.001), as was the difference between discharge score and admission score (indicating clinical improvement). More patients admitted with mechanical ventilation were successfully extubated in the deferoxamine group (61.5 vs. 14.3%, 95% CI: 15-73%; P=0.001), with a higher median ventilator-free days. There were no differences between groups in adverse events. Deferoxamine group was associated with hospital mortality [odds ratio=0.46 (95% CI: 0.22-0.95); P=0.04].

Conclusions

Deferoxamine may have mortality and clinical improvement benefits in COVID-19 adults admitted to ICU. Further powered and controlled studies are required.

Reduced sulfatide content in deferoxamine-induced senescent HepG2 cells

Iron chelators, such as deferoxamine, exert an anticancer effect by altering the activity of biomolecules critical for regulation of the cell cycle, cell metabolism, and apoptotic processes. Thus, iron chelators are sometimes used in combination with radio- and/or chemotherapy in the treatment of cancer. The possibility that deferoxamine could induce a program of senescence similar to radio- and/or chemotherapy, fostering adaptation in the treatment of cancer cells, is not fully understood. Using established biochemical techniques, biomarkers linked to lipid composition, and coherent anti-Stokes Raman scattering microscopy, we demonstrated that hepatocellular carcinoma-derived HepG2 cells survive after deferoxamine treatment, acquiring phenotypic traits and representative hallmarks of senescent cells. The results support the view that deferoxamine acts in HepG2 cells to produce oxidative stress-induced senescence by triggering sequential mitochondrial and lysosomal dysfunction accompanied by autophagy blockade. We also focused on the lipidome of senescent cells after deferoxamine treatment. Using mass spectrometry, we found that the deferoxamine-induced senescent cells presented marked remodeling of the phosphoinositol, sulfatide, and cardiolipin profiles, which all play a central role in cell signaling cascades, intracellular membrane trafficking, and mitochondria functions. Detection of alterations in glycosphingolipid sulfate species suggested modifications in ceramide generation, and turnover is frequently described in cancer cell survival and resistance to chemotherapy. Blockade of ceramide generation may explain autophagic default, resistance to apoptosis, and the onset of senescence. DATA AVAILABILITY STATEMENT: All analyses relevant to the study were included in the article or uploaded as Supplementary Information.

Drug-Delivery Nanoplatform with Synergistic Regulation of Angiogenesis-Osteogenesis Coupling for Promoting Vascularized Bone Regeneration

It has been confirmed that substantial vascularization is an effective strategy to heal large-scale bone defects in the field of bone tissue engineering. The local application of deferoxamine (DFO) is among the most common and effective methods for promoting the formation of blood vessels, although its short half-life in plasma, rapid clearance, and poor biocompatibility limit its therapeutic suitability. Herein, zeolitic imidazolate framework-8 (ZIF-8) was selected as a vehicle to extend the half-life of DFO. In the present study, a nano DFO-loaded ZIF-8 (DFO@ZIF-8) drug delivery system was established to promote angiogenesis-osteogenesis coupling. The nanoparticles were characterized, and their drug loading efficiency was examined to confirm the successful synthesis of nano DFO@ZIF-8. Additionally, due to the sustained release of DFO and Zn²⁺, DFO@ZIF-8 NPs were able to promote angiogenesis in human umbilical vein endothelial cells (HUVECs) culture and osteogenesis in bone marrow stem cells (BMSCs) in vitro. Furthermore, the DFO@ZIF-8 NPs promoted vascularization by enhancing the expression of type H vessels and a vascular network. The DFO@ZIF-8 NPs promoted bone regeneration in vivo by increasing the expression of OCN and BMP-2. RNA sequencing analysis revealed that the PI3K-AKT-MMP-2/9 and HIF-1α pathways were upregulated by DFO@ZIF-8 NPs in HUVECs, ultimately leading to the formation of new blood vessels. In addition, the mechanism by which DFO@ZIF-8 NPs promoted bone regeneration was potentially related to the synergistic effect of angiogenesis-osteogenesis coupling and Zn²⁺-mediation of the MAPK pathway. Taken together, DFO@ZIF-8 NPs, which were demonstrated to have low cytotoxicity and excellent coupling of angiogenesis and osteogenesis, represent a promising strategy for the reconstruction of critical-sized bone defects.

Drugs That Mimic Hypoxia Selectively Target EBV-Positive Gastric Cancer Cells

Latent infection of Epstein-Barr virus (EBV) is associated with lymphoid and epithelial cell cancers, including 10% of gastric carcinomas. We previously reported that hypoxia inducible factor-1α (HIF-1α) induces EBV's latent-to-lytic switch and identified several HIF-1α-stabilizing drugs that induce this viral reactivation. Here, we tested three classes of these drugs for preferential killing of the EBV-positive gastric cancer AGS-Akata cell line compared to its matched EBV-negative AGS control. We observed preferential killing with iron chelators [Deferoxamine (DFO); Deferasirox (DFX)] and a prolyl hydroxylase inhibitor (BAY 85-3934 (Molidustat)), but not with a neddylation inhibitor [MLN4924 (Pevonedistat)]. DFO and DFX also induced preferential killing of the EBV-positive gastric cancer AGS-BDneo and SNU-719 cell lines. Preferential killing was enhanced when low-dose DFX (10 μM) was combined with the antiviral prodrug ganciclovir. DFO and DFX induced lytic EBV reactivation in approximately 10% of SNU-719 and 20-30% of AGS-Akata and AGS-BDneo cells. However, neither DFO nor DFX significantly induced synthesis of lytic EBV proteins in xenografts grown in NSG mice from AGS-Akata cells above the level observed in control-treated mice. Therefore, these FDA-approved iron chelators are less effective than gemcitabine at promoting EBV reactivation in vivo despite their high specificity and efficiency in vitro.

Temporary induction of hypoxic adaptations by preconditioning fails to enhance Schwann cell transplant survival after spinal cord injury

Hypoxic preconditioning is protective in multiple models of injury and disease, but whether it is beneficial for cells transplanted into sites of spinal cord injury (SCI) is largely unexplored. In this study, we analyzed whether hypoxia-related preconditioning protected Schwann cells (SCs) transplanted into the contused thoracic rat spinal cord. Hypoxic preconditioning was induced in SCs prior to transplantation by exposure to either low oxygen (1% O₂ ) or pharmacological agents (deferoxamine or adaptaquin). All preconditioning approaches induced hypoxic adaptations, including increased expression of HIF-1α and its target genes. These adaptations, however, were transient and resolved within 24 h of transplantation. Pharmacological preconditioning attenuated spinal cord oxidative stress and enhanced transplant vascularization, but it did not improve either transplanted cell survival or recovery of sensory or motor function. Together, these experiments show that hypoxia-related preconditioning is ineffective at augmenting either cell survival or the functional outcomes of SC-SCI transplants. They also reveal that the benefits of hypoxia-related adaptations induced by preconditioning for cell transplant therapies are not universal.

Polymeric iron chelators for enhancing 5-aminolevulinic acid-induced photodynamic therapy

5-Aminolevulinic acid (5-ALA) is an amino acid that can be metabolized into a photosensitizer, protoporphyrin IX (PpIX) selectively in a tumor cell, permitting minimally invasive photodynamic diagnosis/therapy. However, some malignant tumor cells have excess intracellular labile iron and facilitate the conversion of PpIX into heme, which compromises the therapeutic potency of 5-ALA. Here, we examined the potential of chelation of such unfavorable intratumoral labile iron in photodynamic therapy (PDT) with 5-ALA hydrochloride, using polymeric iron chelators that we recently developed. The polymeric iron chelator efficiently inactivated the intracellular labile iron in cultured cancer cells and importantly enhanced the accumulation of PpIX, thereby improving the cytotoxicity upon photoirradiation. Even in in vivo study with subcutaneous tumor models, the polymeric iron chelator augmented the intratumoral accumulation of PpIX and the PDT effect. This study suggests that our polymeric iron chelator could be a tool for boosting the effect of 5-ALA-induced PDT by modulating tumor microenvironment.

The Role of Iron-Chelating Therapy in Improving Neurological Outcome in Patients with Intracerebral Hemorrhage: Evidence-Based Case Report

Current primary intracerebral hemorrhage (ICH) treatments focus on limiting hematoma volume by lowering blood pressure, reversing anticoagulation, or hematoma evacuation. Nevertheless, there is no effective strategy to protect the brain from secondary injury due to ICH. Excess heme and iron as by-products of lysing clots in ICH might contribute to this secondary injury by triggering perihematomal edema. We present a clinical situation of an ICH case where iron-chelating therapy might be beneficial, as supported by scientific evidence. We looked through four databases (Pubmed, Cochrane, Embase, and Google Scholar) to find studies assessing the efficacy of iron-chelating therapy in ICH patients. Validity, importance, and applicability (VIA) of the included articles were appraised using worksheets from the Oxford Centre for Evidence-Based Medicine. Two out of five eligible studies were valid, important, and applicable to our patient. Both studies showed the positive effects of iron-chelating therapy on neurological outcome, as measured by National Institutes of Health Stroke Scale (NIHSS) score and modified Rankin Score (mRS). The beneficial effects of deferoxamine were demonstrated within the moderate volume (10-30 mL) subgroup, with a positive relative risk reduction (RRR) and low number needed to treat (six persons). Based on our appraisal, we considered iron-chelating therapy as an additional therapy for ICH patients, given its benefits and adverse effects. More specific studies using a larger sample size, focusing on moderate-volume ICH, and using standardized neurological outcomes are encouraged.

Oral Non-absorbable Polymer-Deferoxamine Conjugates for Reducing Dietary Iron Absorption

Hereditary hemochromatosis (HH) is a non-transfusional genetic iron overload (IO) disease wherein patients are not able to regulate dietary iron absorption, which ultimately leads to excess cellular iron accumulation. Preventative measures for HH mainly include phlebotomy and asking patients to minimize dietary iron intake. To investigate alternative iron reduction strategies, we report on prophylactic non-absorbable polymer-deferoxamine (DFO) conjugates capable of chelating and reducing excessive gut uptake of dietary iron. Three different sizes of the conjugates (56 nm, 256 nm, and 7.4 μm) were prepared, and their physicochemical properties, transit times in the gut under fed/fasted conditions, acute safety, and efficacy at reducing iron absorption in a dietary iron-overload mouse model were investigated. The conjugates were synthesized through reverse phase water-in-oil (w/o) emulsions, followed by conjugation of DFO to the resulting polymer scaffolds. In vitro studies using Caco-2 transwell assays showed that the conjugates could not permeate across the monolayer, were poorly endocytosed, and did not induce cellular toxicity. In vivo mouse studies via oral gavage demonstrated that polymer-DFO conjugates remained in the gastrointestinal (GI) tract for up to 12 h and significantly prevented escalation of serum ferritin levels and excess liver iron accumulation. Ex vivo images of the duodenum suggest that nanometer-sized conjugates (56 and 246 nm) perform better at chelating dietary iron based on longer retention times (i.e., entrapment in the villi of the duodenum) and an overall slower transit from the GI tract compared to larger micron-sized (7.4 μm) conjugates. Overall, nanometer-sized polymer-DFO conjugates were orally non-absorbable, appeared safe, and were more efficacious at reducing dietary iron absorption when taken with non-heme containing food.

Curcumin and N-Acetylcysteine Nanocarriers Alone or Combined with Deferoxamine Target the Mitochondria and Protect against Neurotoxicity and Oxidative Stress in a Co-Culture Model of Parkinson's Disease

As the blood-brain barrier (BBB) prevents most compounds from entering the brain, nanocarrier delivery systems are frequently being explored to potentially enhance the passage of drugs due to their nanometer sizes and functional characteristics. This study aims to investigate whether Pluronic® F68 (P68) and dequalinium (DQA) nanocarriers can improve the ability of curcumin, n-acetylcysteine (NAC) and/or deferoxamine (DFO), to access the brain, specifically target mitochondria and protect against rotenone by evaluating their effects in a combined Transwell® hCMEC/D3 BBB and SH-SY5Y based cellular Parkinson’s disease (PD) model. P68 + DQA nanoformulations enhanced the mean passage across the BBB model of curcumin, NAC and DFO by 49%, 28% and 49%, respectively (p < 0.01, n = 6). Live cell mitochondrial staining analysis showed consistent co-location of the nanocarriers within the mitochondria. P68 + DQA nanocarriers also increased the ability of curcumin and NAC, alone or combined with DFO, to protect against rotenone induced cytotoxicity and oxidative stress by up to 19% and 14% (p < 0.01, n = 6), as measured by the MTT and mitochondrial hydroxyl radical assays respectively. These results indicate that the P68 + DQA nanocarriers were successful at enhancing the protective effects of curcumin, NAC and/or DFO by increasing the brain penetrance and targeted delivery of the associated bioactives to the mitochondria in this model. This study thus emphasises the potential effectiveness of this nanocarrier strategy in fully utilising the therapeutic benefit of these antioxidants and lays the foundation for further studies in more advanced models of PD.

Effects of medications on hypoxia-inducible factor in the retina: A review

Hypoxia-inducible factor (HIF) plays a critical role in the mechanisms that allow cells to adapt to various oxygen levels in the environment. Specifically, HIF-1⍺ has shown to be widely involved in cellular repair, survival, and energy metabolism. HIF-1⍺ has also been found in increased levels in cancer cells, highlighting the importance of balance in the hypoxic response. Promoting HIF-1⍺ activity as a potential therapy for degenerative diseases and inhibiting HIF-1⍺ as a therapy for pathologies with overactive cell proliferation are actively being explored. Digoxin and metformin, HIF-1⍺ inhibitors, and deferoxamine and ⍺-ketoglutarate analogues, HIF-1⍺ activators, are being studied for application in age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa. However, these same medications have retinal toxicities that must be assessed before implementation of therapeutic care. Herein, we highlight the duality of therapeutic and toxic potential of HIF-1⍺ that must be carefully assessed prior to its clinical application in retinal disorders.

Chelating the valley of death: Deferoxamine's path from bench to wound clinic

There is undisputable benefit in translating basic science research concretely into clinical practice, and yet, the vast majority of therapies and treatments fail to achieve approval. The rift between basic research and approved treatment continues to grow, and in cases where a drug is granted approval, the average time from initiation of human trials to regulatory marketing authorization spans almost a decade. Albeit with these hurdles, recent research with deferoxamine (DFO) bodes significant promise as a potential treatment for chronic, radiation-induced soft tissue injury. DFO was originally approved by the Food and Drug Administration (FDA) in 1968 for the treatment of iron overload. However, investigators more recently have posited that its angiogenic and antioxidant properties could be beneficial in treating the hypovascular and reactive-oxygen species-rich tissues seen in chronic wounds and radiation-induced fibrosis (RIF). Small animal experiments of various chronic wound and RIF models confirmed that treatment with DFO improved blood flow and collagen ultrastructure. With a well-established safety profile, and now a strong foundation of basic scientific research that supports its potential use in chronic wounds and RIF, we believe that the next steps required for DFO to achieve FDA marketing approval will include large animal studies and, if those prove successful, human clinical trials. Though these milestones remain, the extensive research thus far leaves hope for DFO to bridge the gap between bench and wound clinic in the near future.

Iron; Benefits or threatens (with emphasis on mechanism and treatment of its poisoning)

Iron is a necessary biological element and one of the richest in the human body, but it can cause changes in cell function and activity control. Iron is involved in a wide range of oxidation - reduction activities. Whenever iron exceeds the cellular metabolic needs, its excess causes changes in the products of cellular respiration, such as superoxide, hydrogen peroxide and hydroxyl. The formation of these compounds causes cellular toxicity. Lack of control over reactive oxygen species causes damages to DNA, proteins, and lipids. Conversely, superoxide, hydrogen peroxide and hydroxyl are reactive oxygen species, using antioxidants, restoring DNA function, and controlling iron stores lead to natural conditions. Iron poisoning causes clinical manifestations in the gastrointestinal tract, liver, heart, kidneys, and hematopoietic system. When serum iron is elevated, serum iron concentrations, total iron-binding capacity (TIBC) and ferritin will also increase. Supportive care is provided by whole bowel irrigation (WBI), esophagogastroduodenoscopy is required to evaluate mucosal injury and remove undissolved iron tablets. The use of chelator agents such as deferoxamine mesylate, deferasirox, deferiprone, deferitrin are very effective in removing excess iron. Of course, the combined treatment of these chelators plays an important role in increasing iron excretion, and reducing side effects.

Evaluation of Optical Coherence Tomography Findings and Choroidal Thickness in Beta-Thalassemia Major Patients Using Chelation Therapy

Objectives

This study aims to analyze the posterior segment of the eye in children with thalassemia major (TM) treated with chelation therapy.

Methods

Forty-four patients diagnosed with TM and 44 age- and gender-matched participants without systemic diseases were included in this cross-sectional comparative study. A complete ophthalmologic examination, including visual acuity and fundus examination, was performed on all participants. The study and control groups' optic coherence tomography (OCT) evaluation was performed with a spectral domain featured OCT device. Central macular thickness (CMT), macular volume, ganglion cell complex (GCC) thickness, retinal nerve fiber layer (RNFL) thickness, subfoveal choroidal thickness (CT), CT at 1 mm temporal to the fovea, CT at 1 mm nasal to the fovea, CT at the 1 mm temporal to the optic nerve head, and CT at the 1 mm nasal to the optic nerve head were compared between the study and control groups.

Results

The mean ages for the study group and for the control group were 15.2±6.2 and 14.2±4.9 years, respectively. The mean subfoveal CT was 287.73±47.04 µm in the TM group and 312.66±39.95 µm in the control group (p=0.014). CT at the nasal to the fovea and temporal to the optic nerve head was thinner in the TM group than in the healthy group. The mean CMT, macular volume, GCC thickness, and RNFL thickness of the study and the control groups were similar. No significant difference was found between the patients with and without deferoxamine therapy concerning macular thickness, GCC thickness, and macular and peripapillary CT.

Conclusion

Our results suggested that subfoveal, perifoveal, and peripapillary CTs were significantly thinner in children with TM than the control group. The use of deferoxamine did not cause a further reduction in CT.

Deferoxamine/magnesium modified β-tricalcium phosphate promotes the bone regeneration in osteoporotic rats

Recently, Deferoxamine (DFO) and magnesium (Mg) have been identified as critical factors for angiogenesis and bone formation. However, in current research studies, there is a lack of focus on whether DFO plus Mg can affect the regeneration of β-tricalcium phosphate (β-TCP) in osteoporosis and through what biological mechanisms. Therefore, the present work was aimed to preparation and evaluate the effect of Deferoxamine/magnesium modified β-tricalcium phosphate promotes (DFO/Mg-TCP) in ovariectomized rats model and preliminary exploration of possible mechanisms. The MC3T3-E1 cells were co-cultured with the exudate of DFO/Mg-TCP and induced to osteogenesis, and the cell viability, osteogenic activity were observed by Cell Counting Kit-8(CCK-8), Alkaline Phosphatase (ALP) staining, Alizarin Red Staining (RES) and Western Blot. In vitro experiments, CCK-8, ALP and ARS staining results show that the mineralization and osteogenic activity of MC3T3-E1increased significantly after intervention by DFO/Mg-TCP, as well as a higher levels of protein expressions including VEGF, OC, Runx-2 and HIF-1α. In vivo experiment, Micro-CT and Histological analysis evaluation show that DFO/Mg-TCP treatment presented the stronger effect on bone regeneration, bone mineralization and biomaterial degradation, when compared with OVX+Mg-TCP group and OVX+TCP group, as well as a higher VEGF, OC, Runx-2 and HIF-1α gene expression. The present study indicates that treatment with DFO/Mg-TCP was associated with increased regeneration by enhancing the function of osteoblasts in an OVX rat.

Designing Deferoxamine-Loaded Flaxseed Gum and Carrageenan-Based Controlled Release Biocomposite Hydrogel Films for Wound Healing

In this study, biocomposite hydrogel films made from flaxseed gum (FSG)/kappa carrageenan (CGN) were fabricated, using potassium chloride as a crosslinker and glycerol as a plasticizer. The composite films were loaded with deferoxamine (DFX), an iron chelator that promotes neovascularization and angiogenesis for the healing of wounds. The properties of the biocomposite hydrogel films, including swelling, solubility, water vapor transmission rate, tensile strength, elongation at break, and Young’s modulus studies, were tested. The films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). In addition, drug release studies in PBS at pH 7.2 were investigated. In vivo analysis was performed by assessing the wound contraction in a full-thickness excisional wound rat model. Hematoxylin & eosin (H & E) and Masson’s trichome staining were performed to evaluate the effect of the films on wound healing progress. The visual and micro-morphological analysis revealed the homogenous structure of the films; however, the elongation at break property decreased within the crosslinked film but increased for the drug-loaded film. The FTIR analysis confirmed the crosslinking due to potassium chloride. A superior resistance towards thermal degradation was confirmed by TGA for the crosslinked and drug-loaded films. Drug release from the optimum film was sustained for up to 24 h. In vivo testing demonstrated 100% wound contraction for the drug-loaded film group compared to 72% for the pure drug solution group. In light of the obtained results, the higher potential of the optimized biocomposite hydrogel film for wound healing applications was corroborated.

Angiogenic Effect of a Nanoniosomal Deferoxamine-Loaded Poly(vinyl alcohol)-Egg White Film as a Promising Wound Dressing

Owing to the noticeable increase in the number of patients with impaired wound healing capabilities, developing bioactive wound dressings with supportive physicomechanical and biological properties for clinical wound management has attracted much more attention nowadays. In this regard, engineered dressings with angiogenesis potential are vital for accelerated tissue regeneration. In the current study, nanoniosomal deferoxamine (DFO)-loaded transparent films of egg white-poly(vinyl alcohol) (PVA/EW/ND) were successfully fabricated at three different PVA/EW ratios (1:0, 1:1, and 1:1.5 wt/wt %) through the thin film hydration and solvent casting methods. The developed films' characterizations were carried out using scanning electron microscopy, Fourier transform infrared spectroscopy analysis, uniaxial tensile strength, water uptake, water vapor transmission rate, in vitro degradation, and drug release. The results demonstrated that the various weight ratios of PVA/EW have a significant effect on the microscopic morphology, equilibrium swelling, degradation, and mechanical properties of the films. The drug release profile exhibited a sustained release of DFO with controlled burst-lag phases resembling the Korsmeyer-Peppas pattern. The cytotoxicity and adhesion analysis using human dermal fibroblasts displays the biocompatibility of the developed PVA/EW/ND films and the formation of cellular colonies on the surface. The in vitro angiogenic capability of the developed films evaluated by the scratch wound assay and microbead-assisted tube formation study showed a significant increase in the rate of migration of human umbilical vein endothelial cells and in the number of tube-like structures. Therefore, the achieved results suggest that the presented PVA/EW/ND film has promising potential for effective wound healing applications.

Binding of Citrate-Fe3+ to Plastic Culture Dishes, an Artefact Useful as a Simple Technique to Screen for New Iron Chelators

NaCT mediates citrate uptake in the liver cell line HepG2. When these cells were exposed to iron (Fe³⁺), citrate uptake/binding as monitored by the association of [¹⁴C]-citrate with cells increased. However, there was no change in NaCT expression and function, indicating that NaCT was not responsible for this Fe³⁺-induced citrate uptake/binding. Interestingly however, the process exhibited substrate selectivity and saturability as if the process was mediated by a transporter. Notwithstanding these features, subsequent studies demonstrated that the iron-induced citrate uptake/binding did not involve citrate entry into cells; instead, the increase was due to the formation of citrate-Fe³⁺ chelate that adsorbed to the cell surface. Surprisingly, the same phenomenon was observed in culture wells without HepG2 cells, indicating the adsorption of the citrate-Fe³⁺ chelate to the plastic surface of culture wells. We used this interesting phenomenon as a simple screening technique for new iron chelators with the logic that if another iron chelator is present in the assay system, it would compete with citrate for binding to Fe³⁺ and prevent the formation and adsorption of citrate-Fe³⁺ to the culture well. This technique was validated with the known iron chelators deferiprone and deferoxamine, and with the bacterial siderophore 2,3-dihydroxybenzoic acid and the catechol carbidopa.

Hepatic Macrophage Abundance and Phenotype in Aging and Liver Iron Accumulation

Liver macrophages serve important roles in iron homeostasis through phagocytosis of effete erythrocytes and the export of iron into the circulation. Conversely, intracellular iron can alter macrophage phenotype. Aging increases hepatic macrophage number and nonparenchymal iron, yet it is unknown whether age-related iron accumulation alters macrophage number or phenotype. To evaluate macrophages in a physiological model of iron loading that mimicked biological aging, young (6 mo) Fischer 344 rats were given one injection of iron dextran (15 mg/kg), and macrophage number and phenotype were evaluated via immunohistochemistry. A separate group of old (24 mo) rats was treated with 200 mg/kg deferoxamine every 12 h for 4 days. Iron administration to young rats resulted in iron concentrations that matched the values and pattern of tissue iron deposition observed in aged animals; however, iron did not alter macrophage number or phenotype. Aging resulted in significantly greater numbers of M1 (CD68⁺) and M2 (CD163⁺) macrophages in the liver, but neither macrophage number nor phenotype were affected by deferoxamine. Double-staining experiments demonstrated that both M1 (iNOS⁺) and M2 (CD163⁺) macrophages contained hemosiderin, suggesting that macrophages of both phenotypes stored iron. These results also suggest that age-related conditions other than iron excess are responsible for the accumulation of hepatic macrophages with aging.

Endolysosome Iron Chelation Inhibits HIV-1 Protein-Induced Endolysosome De-Acidification-Induced Increases in Mitochondrial Fragmentation, Mitophagy, and Cell Death

People with human immunodeficiency virus-1 (PLWH) experience high rates of HIV-1-associated neurocognitive disorders (HANDs); clinical symptoms range from being asymptomatic to experiencing HIV-associated dementia. Antiretroviral therapies have effectively prolonged the life expectancy related to PLWH; however, the prevalence of HANDs has increased. Implicated in the pathogenesis of HANDs are two HIV-1 proteins, transactivator of transcription (Tat) and gp120; both are neurotoxic and damage mitochondria. The thread-like morphological features of functional mitochondria become fragmented when levels of reactive oxygen species (ROS) increase, and ROS can be generated via Fenton-like chemistry in the presence of ferrous iron (Fe²⁺). Endolysosomes are central to iron trafficking in cells and contain readily releasable Fe²⁺ stores. However, it is unclear whether the endolysosome store is sufficient to account for insult-induced increases in levels of ROS, mitochondrial fragmentation, autophagy, and cell death. Using U87MG astrocytoma and SH-SY5Y neuroblastoma cells, we determined that chloroquine (CQ), Tat, and gp120 all (1) de-acidified endolysosomes, (2) decreased endolysosome numbers and increased endolysosome sizes, (3) increased mitochondrial numbers (fragmentation), (4) increased autophagosome numbers, (5) increased autolysosome numbers, (6) increased mitochondrial fragments within endolysosomes, and (7) increased cell death. These effects were all blocked by the endolysosome-specific iron chelator deferoxamine (DFO). Thus, the endolysosome de-acidification-induced release of endolysosome Fe²⁺ is sufficient to account for inter-organellar signaling events and cell biology consequences of HIV-1 proteins, including mitochondrial fragmentation, autophagy, and cell death.

[Effects of systemic drugs on the development of drug-induced retinopathy]

This article reviews information on possible adverse events occurring in the organ of vision - in particular, the retina - after using systemic drugs, discusses the drugs that lead to drug-induced retinopathy most often, and describes histomorphological changes and modern understanding of the pathogenesis of damage to retinal structures.

Injectable Thermosensitive Hydrogels for a Sustained Release of Iron Nanochelators

Deferoxamine (DFO) is an FDA-approved iron-chelating agent which shows good therapeutic efficacy, however, its short blood half-life presents challenges such as the need for repeated injections or continuous infusions. Considering the lifelong need of chelating agents for iron overload patients, a sustained-release formulation that can reduce the number of chelator administrations is essential. Here, injectable hydrogel formulations prepared by integrating crosslinked hyaluronic acid into Pluronic F127 for an extended release of DFO nanochelators are reported. The subcutaneously injected hydrogel shows a thermosensitive sol-gel transition at physiological body temperature and provides a prolonged release of renal clearable nanochelators over 2 weeks, resulting in a half-life 47-fold longer than that of the nanochelator alone. In addition, no chronic toxicity of the nanochelator-loaded hydrogel is confirmed by biochemical and histological analyses. This injectable hydrogel formulation with DFO nanochelators has the potential to be a promising formulation for the treatment of iron overload disorders.

Iron Effects on Clostridioides difficile Toxin Production and Antimicrobial Susceptibilities

Despite the benefits of red blood cell (RBC) transfusion therapy, it can render patients vulnerable to iron overload. The excess iron deposits in various body tissues cause severe complications and organ damage such as cardiotoxicity and mold infections. Clostridioides difficile infection (CDI) is the most common cause of nosocomial diarrhea among cancer patients and is associated with significant morbidity and mortality. Our study aims to determine the role of iron overload and the effects of iron chelators on CDI. Our results demonstrated that iron (Fe3+) stimulated the growth of C. difficile with increased colony formation units (CFU) in a dose-dependent manner. Exposure to excess iron also increased the gene expression levels of tcdA and tcdB. The production of C. difficile toxin A, necessary for the pathogenesis of C. difficile, was also elevated after iron treatment. In the presence of excess iron, C. difficile becomes less susceptible to metronidazole with significantly elevated minimum inhibitory concentration (MIC) but remains susceptible to vancomycin. Iron-stimulated colony formation and production of C. difficile toxins were effectively diminished by iron chelator deferoxamine co-treatment. Incorporating iron overload status as a potential factor in developing a risk prediction model of CDI and antibiotic treatment response may aid clinical practitioners in optimizing CDI management in oncology patients.

Deferoxamine Alleviates Osteoarthritis by Inhibiting Chondrocyte Ferroptosis and Activating the Nrf2 Pathway

Objective: Osteoarthritis (OA) is a common disease with a complex pathology including mechanical load, inflammation, and metabolic factors. Chondrocyte ferroptosis contributes to OA progression. Because iron deposition is a major pathological event in ferroptosis, deferoxamine (DFO), an effective iron chelator, has been used to inhibit ferroptosis in various degenerative disease models. Nevertheless, its OA treatment efficacy remains unknown. We aimed to determine whether DFO alleviates chondrocyte ferroptosis and its effect on OA and to explore its possible mechanism. Methods: Interleukin-1β (IL-1β) was used to simulate inflammation, and chondrocyte ferroptosis was induced by erastin, a classic ferroptosis inducer. A surgical destabilized medial meniscus mouse model was also applied to simulate OA in vivo, and erastin was injected into the articular cavity to induce mouse knee chondrocyte ferroptosis. We determined the effects of DFO on ferroptosis and injury-related events: chondrocyte inflammation, extracellular matrix degradation, oxidative stress, and articular cartilage degradation. Results: IL-1β increased the levels of ROS, lipid ROS, and the lipid peroxidation end product malondialdehyde (MDA) and altered ferroptosis-related protein expression in chondrocytes. Moreover, ferrostatin-1 (Fer-1), a classic ferroptosis inhibitor, rescued the IL-1β-induced decrease in collagen type II (collagen II) expression and increase in matrix metalloproteinase 13 (MMP13) expression. Erastin promoted MMP13 expression in chondrocytes but inhibited collagen II expression. DFO alleviated IL-1β- and erastin-induced cytotoxicity in chondrocytes, abrogated ROS and lipid ROS accumulation and the increase in MDA, improved OA-like changes in chondrocytes, and promoted nuclear factor E2-related factor 2 (Nrf2) antioxidant system activation. Finally, intra-articular injection of DFO enhanced collagen II expression in OA model mice, inhibited erastin-induced articular chondrocyte death, and delayed articular cartilage degradation and OA progression. Conclusion: Our research confirms that ferroptosis occurs in chondrocytes under inflammatory conditions, and inhibition of chondrocyte ferroptosis can alleviate chondrocyte destruction. Erastin-induced chondrocyte ferroptosis can stimulate increased MMP13 expression and decreased collagen II expression in chondrocytes. DFO can suppress chondrocyte ferroptosis and promote activation of the Nrf2 antioxidant system, which is essential for protecting chondrocytes. In addition, ferroptosis inhibition by DFO injection into the articular cavity may be a new OA treatment.

Deferoxamine ameliorated Al(mal)3-induced neuronal ferroptosis in adult rats by chelating brain iron to attenuate oxidative damage

Aluminum (Al), a neurotoxic element, can induce Alzheimer's disease-like (AD-like) changes by triggering neuronal death. Iron homeostasis disturbance has also been implicated in Alzheimer's disease (AD), and excess iron exacerbates oxidative damage and cognitive defects. Ferroptosis is a nonapoptotic form of cell death dependent upon intracellular iron. However, the involvement of neuronal death induced by aluminum maltolate (Al(mal)₃) in the pathogenesis of AD remains elusive. In this study, the results of three different behavioral experiments suggested that the learning and memory ability deteriorated and autonomous activity declined of these rats that exposed Al(mal)₃ were alleviated by deferoxamine (DFO). Transmission electron microscope observations showed that the membrane was ruptured, and the membrane density increased and ridge disappearance (the most prominent characteristic of ferroptosis) in the perinuclear and cytoplasmic compartments of the hippocampal neurons were perceived in the exposure group, while the DFO group and 18 μM/kg Al(mal)₃+DFO group were alleviated compared with 18 μM/kg Al(mal)₃. In addition, DFO prevented oxidative stress, such as increased glutathione (GSH) and decreased malondialdehyde (MDA) and reactive oxygen species (ROS), while the latter two indexes had the same changing tendency as the total iron of brain tissue. These data indicated that Al(mal)₃ could cause ferroptosis in Sprague-Dawley (SD) rat neurons, which was inhibited by DFO via reducing the content of iron and increasing the ability of cells to resist oxidative damage.

UAMC-3203 or/and Deferoxamine Improve Post-Resuscitation Myocardial Dysfunction Through Suppressing Ferroptosis in a Rat Model of Cardiac Arrest

ABSTRACT

Blocking ferroptosis reduces ischemia-reperfusion injury in some pathological contexts. However, there is no evidence that ferroptosis contributes to post-resuscitation myocardial dysfunction (PRMD). Here, we evaluated the therapeutic performance of ferroptosis inhibitors (UAMC-3203 or/and Deferoxamine) on the PRMD in a rat model of cardiac arrest and surveyed the changes of essential ferroptosis markers in the myocardium. Remarkably, all treatments reduce the severity of cardiac dysfunction and microcirculation hypoperfusion after resuscitation compared with control. Consistently, we observe that the ferroptosis marker Glutathione peroxidase 4, 4-hydroxynonenal and non-heme iron altered (1 ± 0.060 vs. 0.021 ± 0.016, 1 ± 0.145 vs. 3.338 ± 0.221, 52.010 ± 3.587 ug/g vs. 70.500 ± 3.158 ug/g, all P < 0.05) in the myocardium after resuscitation. These changes were significantly suppressed by UAMC-3203 [(0.187 ± 0.043, 2.848 ± 0.169, all P < 0.05), (72.43 ± 4.920 ug/g, P  > 0.05)], or Deferoxamine (0.203 ± 0.025, 2.683 ± 0.273, 55.95 ± 2.497 ug/g, all P < 0.05). Briefly, UAMC-3203 or/and Deferoxamine improve post-resuscitation myocardial dysfunction and provide evidence of ferroptosis involvement, suggesting that ferroptosis inhibitors could potentially provide an innovative therapeutic approach for mitigating the myocardial damage caused by cardiopulmonary resuscitation.