[Chemical Species Change of Radionuclides by Microorganisms: Effects of Exudated Siderophores].

Microbial exudates including siderophore, which changes chemical species of actinides and lanthanides. We have investigated effects of desferrioxamine B (DFOB; one of the siderophores) and siderophore-like organic molecules (SLOM) on the adsorption of lanthanides by microbial cells, aluminium oxide (Al2O3), and manganese (Mn) oxides. When DFOB was present, the distribution coefficients of cerium (Ce) were measured to be lower than those of neighboring elements of lanthanum (La) and praseodymium (Pr) (Negative anomaly of Ce adsorption). Even though initial oxidation state of Ce in the solution was III, that was changed to IV after the addition of DFOB, indicating that Ce(III) was oxidized by forming complex with DFOB. When lanthanides were adsorbed by biogenic Mn(IV) oxides, negative anomaly of Ce adsorption was observed in the sorption in alkaline solution. Ce(III) was oxidized to forme the complexes of Ce(IV) with SLOM in the solution. These results show that siderophore possesses high performance of oxidation of Ce(III) to Ce(IV) during association, affectiong the adsorption behavior of Ce. After Fukushima accident, radioactive Cs accumulation by Eleutherococcus sciadophylloides (Koshiabura) caused by the dissolution of Fe from soil around the roots, that was dominated by siderophore releasing microorganisms (SB). These SBs may enhance dissolution of iron (Fe) and uranium (U) phases in the nuclear fuel debris formed in the nuclear reactors in Fukushima Daiichi nuclear power plant. Thus, in the interaction between microorganisms and radionuclides, SLOMs discharged by microorganisms are deeply involved in the chemical state change of radionuclides.

Application of Deferoxamine in Tissue Regeneration Attributed to Promoted Angiogenesis.

Deferoxamine, an iron chelator used to treat diseases caused by excess iron, has had a Food and Drug Administration-approved status for many years. A large number of studies have confirmed that deferoxamine can reduce inflammatory response and promote angiogenesis. Blood vessels play a crucial role in sustaining vital life by facilitating the delivery of immune cells, oxygen, and nutrients, as well as eliminating waste products generated during cellular metabolism. Dysfunction in blood vessels may contribute significantly to the development of life-threatening diseases. Anti-angiogenesis therapy and pro-angiogenesis/angiogenesis strategies have been frequently recommended for various diseases. Herein, we describe the mechanism by which deferoxamine promotes angiogenesis and summarize its application in chronic wounds, bone repair, and diseases of the respiratory system. Furthermore, we discuss the drug delivery system of deferoxamine for treating various diseases, providing constructive ideas and inspiration for the development of new treatment strategies.

The effect of aqueous extract of Iranian oak (Quercus brantii) on antioxidant capacity and oxidative stress in beta-thalassemia patients: Randomized controlled trial.

BACKGROUND AND AIM: Frequent administration of blood in ß-thalassemia patients can lead to over-loaded iron, a reduction in the levels of antioxidant activities in the body, and oxidative stress. This study was done to evaluate the antioxidant and protective effect of aqueous oak (Quercus brantii) extract supplementation on these patients. METHODS: This clinical trial was performed on 60 major ß thalassemia patients dividing them into intervention and control groups. In addition to taking desferrioxamine (DFO), the control and intervention groups received respectively placebo capsule supplementation and aqueous Quercus extract capsules (300 mg/day) for 3 months. Serum lipid profiles (LDL-c, HDL-c, triglyceride), Total Antioxidant Capacity (TAC), Glucose, Uric acid, urea nitrogen (BUN), Creatinine, LFT (Liver Function Tests) such as SGOT, SGPT, ALP, Total bilirubin, Direct bilirubin, ferritin, MDA and carbonyl protein (CO) levels were measured before and after the period. In addition, the activity of catalase (CAT), and superoxide dismutase (SOD) was measured in the red blood cell. Furthermore, antioxidant activity and total phenolic content of aqueous Quercus were recorded to standardize capsule formulation. RESULTS: Mean serum MDA, and protein CO, significantly decreased in the intervention group with ß-TM after 3 months of treatment with Quercus extract. In addition, the superoxide dismutase (SOD) enzyme and Total antioxidant capacity (TAC) significantly increased in comparison with the control group. Changes in serum creatinine, BUN, and alanine transferase were not significant. In the study, Quercus extract capsules contain 48/56 mg gallic acid/g (dry extract) total phenol, 58/6 mg/g (dry extract), and flavonoids of 63/8 µg/ml antioxidant power which by GC/MS analysis has been measured. At the end of the study, serum MDA decreased from 48.65 ± 8.74 to 43.94 ± 10.39 µ mol/l after administration of oak extract and protein CO dropped from 2.44 ± 0.38 to 1.2 ± 0.31 nmol DNPH/mg protein after administration of the oak extract. At the end of the study serum, TAC increased in patients interventional group from 907 ± 319 to 977 ± 327 µmol FeSO4/l compared to the control group 916 ± 275 to 905.233 ± 233 µmol FeSO4/l with placebo, and SOD increased from 1577 ± 325 to 2079 ± 554 U/l (compared to 1687 ± 323 U/l with placebo). The treatment effect of Quercus was measured using a mixed-effects model of variance analysis for changes in MDA, protein CO, TAC, and SOD, with significant effects being demonstrated for each laboratory parameter (P = 0.15, P = 0.001, P = 0.02, and P < 0.003, respectively). CONCLUSIONS: Aqueous Quercus extract, due to its high antioxidant potential, reduced MDA, serum carbonyl protein, and increased superoxide dismutase activity effectively decreased serum OS and enhanced serum antioxidant capacity in patients with ß-thalassemia major. oak given as an adjuvant therapy to standard iron chelators may provide an improvement in the OS measurements obtained in these patients. REGISTRATION INFORMATION: This study was submitted, evaluated, and approved by the Iranian Registry of Clinical Trials (IRCT: http://www.irct.ir; IRCT2015101411819N4), which was established for national medical schools in Iran.

COMPARATIVE STUDY OF OXIDATIVE STRESS IN PATIENTS WITH Β -THALASSEMIA MAJOR ON DEFERASIROX VERSUS DEFEROXAMINE THERAPY.

Accumulation of iron in vital organs is increasingly challenging in clinical settings during the lifespan of thalassemia patients. Iron overload hurdle these organs to redox imbalances. Commonly used iron-chelating agents in (deferasirox and, deferoxamine) could have a positive antioxidant role. Therefore, the aim of this study was designed to compare the effects of deferasirox and, deferoxamine, iron-chelating agents in oxidative stress in patients with ß-thalassemic major. In this case series comparative study, 60 known cases of ß-thalassemic patients receiving chelating agents therapy were divided into two groups of thirty, group one consisted of 30 patients 16 male and14 female, who received oral agent deferasirox tablets at dose 20-40mg/kg. Group two consisted of 30 patients, 16 male and 14 female, on intravenous therapy with Deferoxamine at a dose of 20-50mg/kg, Another thirty healthy individuals matched with age and gender, were kept as a control group. Total antioxidant capacity (TAOC) and Malondialdehyde (MDA) were measured in all studied groups. The three groups were similar in terms of age, and gender, A statistically non-significant difference in age (p>0.05) existed between the control and patient groups (10.9±2.93; 11.2±4.1*;11.6±3.6*) respectively. The number of patients in to control group and male-to-female numbers were matched since the ratios were similar. A statistically non-significant difference in BMI (p>0.05) existed between the control and patient groups (17±2, 17.2±2, 18±2.4*) respectively. TAOC is lower in-patient groups, when compared with the control group (27.8 ± 10.7; 32.5 ± 10.2; and 79.5 ± 7 u/ml) respectively, while the MDA value is higher when compared with the control group (7.2±4.6 and, 6.6±4.42; and 0.57±0.26; nmol/ml) respectively. The TAOC in patients group on Deferoxamine, is higher, while MDA is lower than in patients on Defrasirox. The TAOC in patients was reduced and Oxidative stress was enhanced in patients with thalassemia. Deferoxamine is more effective in modulating redox status.

Activating Angiogenesis and Immunoregulation to Propel Bone Regeneration via Deferoxamine-Laden Mg-Mediated Tantalum Oxide Nanoplatform.

Vascularization and inflammation management are essential for successful bone regeneration during the healing process of large bone defects assisted by artificial implants/fillers. Therefore, this study is devoted to the optimization of the osteogenic microenvironment for accelerated bone healing through rapid neovascularization and appropriate inflammation inhibition that were achieved by applying a tantalum oxide (TaO)-based nanoplatform carrying functional substances at the bone defect. Specifically, TaO mesoporous nanospheres were first constructed and then modified by functionalized metal ions (Mg2+) with the following deferoxamine (DFO) loading to obtain the final product simplified as DFO-Mg-TaO. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the product was homogeneously dispersed hollow nanospheres with large specific surface areas and mesoporous shells suitable for loading Mg2+ and DFO. The biological assessments indicated that DFO-Mg-TaO could enhance the adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The DFO released from DFO-Mg-TaO promoted angiogenetic activity by upregulating the expressions of hypoxia-inducible factor-1 (HIF-1α) and vascular endothelial growth factor (VEGF). Notably, DFO-Mg-TaO also displayed anti-inflammatory activity by reducing the expressions of pro-inflammatory factors, benefiting from the release of bioactive Mg2+. In vivo experiments demonstrated that DFO-Mg-TaO integrated with vascular regenerative, anti-inflammatory, and osteogenic activities significantly accelerated the reconstruction of bone defects. Our findings suggest that the optimized DFO-Mg-TaO nanospheres are promising as multifunctional fillers to speed up the bone healing process.

Promoting tissue repair using deferoxamine nanoparticles loaded biomimetic gelatin/HA composite hydrogel.

To effectively address underlying issues and enhance the healing process of hard-to-treat soft tissue defects, innovative therapeutic approaches are required. One promising strategy involves the incorporation of bioactive substances into biodegradable scaffolds to facilitate synergistic tissue regeneration, particularly in vascular regeneration. In this study, we introduce a composite hydrogel design that mimics the extracellular matrix by covalently combining gelatin and hyaluronic acid (HA), with the encapsulation of deferoxamine nanoparticles (DFO NPs) for potential tissue regeneration applications. Crosslinked hydrogels were fabricated by controlling the ratio of HA in the gelatin-based hydrogels, resulting in improved mechanical properties, enhanced degradation ability, and optimised porosity, compared with hydrogel formed by gelatin alone. The DFO NPs, synthesized using a double emulsion method with poly (D,L-lactide-co-glycolide acid), exhibited a sustained release of DFO over 12 d. Encapsulating the DFO NPs in the hydrogel enabled controlled release over 15 d. The DFO NPs, composite hydrogel, and the DFO NPs loaded hydrogel exhibited excellent cytocompatibility and promoted cell proliferationin vitro. Subcutaneous implantation of the composite hydrogel and the DFO NPs loaded hydrogel demonstrated biodegradability, tissue integration, and no obvious adverse effects, evidenced by histological analysis. Furthermore, the DFO NPs loaded composite hydrogel exhibited accelerated wound closure and promoted neovascularisation and granular formation when tested in an excisional skin wound model in mice. These findings highlight the potential of our composite hydrogel system for promoting the faster healing of diabetes-induced skin wounds and oral lesions through its ability to modulate tissue regeneration processes.

ALKBH5 targets ACSL4 mRNA stability to modulate ferroptosis in hyperbilirubinemia-induced brain damage.

Bilirubin-induced brain damage is a serious clinical consequence of hyperbilirubinemia, yet the underlying molecular mechanisms remain largely unknown. Ferroptosis, an iron-dependent cell death, is characterized by iron overload and lipid peroxidation. Here, we report a novel regulatory mechanism of demethylase AlkB homolog 5 (ALKBH5) in acyl-coenzyme A synthetase long-chain family member 4 (ACSL4)-mediated ferroptosis in hyperbilirubinemia. Hyperdifferential PC12 cells and newborn Sprague-Dawley rats were used to establish in vitro and in vivo hyperbilirubinemia models, respectively. Proteomics, coupled with bioinformatics analysis, first suggested the important role of ferroptosis in hyperbilirubinemia-induced brain damage. In vitro experiments showed that ferroptosis is activated in hyperbilirubinemia, and ferroptosis inhibitors (desferrioxamine and ferrostatin-1) treatment effectively alleviates hyperbilirubinemia-induced oxidative damage. Notably, we observed that the ferroptosis in hyperbilirubinemia was regulated by m6A modification through the downregulation of ALKBH5 expression. MeRIP-seq and RIP-seq showed that ALKBH5 may trigger hyperbilirubinemia ferroptosis by stabilizing ACSL4 mRNA via m6A modification. Further, hyperbilirubinemia-induced oxidative damage was alleviated through ACSL4 genetic knockdown or rosiglitazone-mediated chemical repression but was exacerbated by ACSL4 overexpression. Mechanistically, ALKBH5 promotes ACSL4 mRNA stability and ferroptosis by combining the 669 and 2015 m6A modified sites within 3' UTR of ACSL4 mRNA. Our findings unveil a novel molecular mechanism of ferroptosis and suggest that m6A-dependent ferroptosis could be an underlying clinical target for the therapy of hyperbilirubinemia.

Manganese overexposure results in ferroptosis through the HIF-1α/p53/SLC7A11 pathway in ICR mouse brain and PC12 cells.

Manganese (Mn) overexposure has been associated with the development of neurological damage reminiscent of Parkinson's disease, while the underlying mechanisms have yet to be fully characterized. This study aimed to investigate the mechanisms leading to injury in dopaminergic neurons induced by Mn and identify novel treatment approaches. In the in vivo and in vitro models, ICR mice and dopaminergic neuron-like PC12 cells were exposed to Mn, respectively. We treated them with anti-ferroptotic agents ferrostatin-1 (Fer-1), deferoxamine (DFO), HIF-1α activator dimethyloxalylglycine (DMOG) and inhibitor LW6. We also used p53-siRNA to verify the mechanism underlying Mn-induced neurotoxicity. Fe and Mn concentrations increased in ICR mice brains overexposed to Mn. Additionally, Mn-exposed mice exhibited movement impairment and encephalic pathological changes, with decreased HIF-1α, SLC7A11, and GPX4 proteins and increased p53 protein levels. Fer-1 exhibited protective effects against Mn-induced both behavioral and biochemical changes. Consistently, in vitro, Mn exposure caused ferroptosis-related changes and decreased HIF-1α levels, all ameliorated by Fer-1. Upregulation of HIF-1α by DMOG alleviated the Mn-associated ferroptosis, while LW6 exacerbated Mn-induced neurotoxicity through downregulating HIF-1α. p53 knock-down also rescued Mn-induced ferroptosis without altering HIF-1α protein expression. Mn overexposure resulted in ferroptosis in dopaminergic neurons, mediated through the HIF-1α/p53/SLC7A11 pathway.

Differential effects of iron chelators on iron burden and long-term morbidity and mortality outcomes in a large cohort of transfusion-dependent ß-thalassemia patients who remained on the same monotherapy over 10 years.

We conducted a retrospective cohort study on 663 transfusion-dependent ß-thalassemia patients receiving the same iron chelation monotherapy with deferoxamine, deferiprone, or deferasirox for up to 10 years (median age 31.8 years, 49.9 % females). Patients on all three iron chelators had a steady and significant decline in serum ferritin over the 10 years (median deferoxamine: -170.7 ng/mL, P = 0.049, deferiprone: -236.7 ng/mL, P = 0.001; deferasirox: -323.7 ng/mL, P < 0.001) yet had no significant change in liver iron concentration or cardiac T2*; while noting that patients generally had low hepatic and cardiac iron levels at study start. Median absolute, relative, and normalized changes were generally comparable between the three iron chelators. Patients receiving deferasirox had the highest morbidity and mortality-free survival probability among the three chelators, although the difference was only statistically significant when compared with deferoxamine (P = 0.037). On multivariate Cox regression analysis, there was no significant association between iron chelator type and the composite outcome of morbidity or mortality. In a real-world setting, there is comparable long-term iron chelation effectiveness between the three available iron chelators for patients with mild-to-moderate iron overload.

Deferoxamine-Loaded Injectable Chitosan-Grafted Chlorogenic Acid/Oxidized Hyaluronic Acid Hybrid Hydrogel with Antibacterial, Anti-inflammatory, and Angiogenesis-Promoting Properties for Diabetic Wound Repair.

Diabetic chronic wounds are notoriously difficult to heal as a result of their susceptibility to infection. To address this issue, we constructed an innovated and adaptable solution in the form of injectable chitosan (CS) hydrogel, denoted as CCOD, with enhanced antibacterial and anti-inflammatory properties. This hydrogel is created through a Schiff base reaction that combines chitosan-grafted chlorogenic acid (CS-CGA) and oxidized hyaluronic acid (OHA) with deferoxamine (DFO) as a model drug. The combination of CS and CGA has demonstrated excellent antibacterial and anti-inflammatory properties, while grafting played a pivotal role in making these positive effects stable. These unique features make it possible to customize injectable hydrogel and fit any wound shape, allowing for more effective and personalized treatment of complex bacterial infections. Furthermore, the hydrogel system is not only effective against inflammation and bacterial infections but also possesses antioxidant and angiogenic abilities, making it an ideal solution for the repair of chronic wounds that have been previously thought of as unmanageable.

Tri-layered core-shell structured deferoxamine magnetic particles promote Microcystis aeruginosa growth.

This experiment prepared magnetic composite siderophores (DMPs) with strong magnetism, excellent adsorption capacity, and high specific surface area. Exploring the synergistic effect of magnetic nanoparticles and siderophores on Microcystis aeruginosa growth under iron-deficient condition, by utilizing the characteristics of the three-layer core-shell structure of DMPs. This study elucidated the potential mechanism by which DMPs promote the cyanobacterial growth through physiological indicators and transcriptome analysis. On the experiment's final day, cell density in DMPs treatment group at 2, 4, and 8 mg/L were 1.10, 1.14 and 1.16 times higher than those in the control group (Ct), respectively. Similarly, chlorophyll and photosynthetic efficiency results showed improved algae growth with increasing DMPs dosage. The microcystin content in DMPs experimental groups at low, medium, and high concentration were 0.91, 0.86, and 0.83 times that of Ct, indicating alleviation of iron deficiency stress. Additionally, based on extracellular polymers, intracellular and extracellular siderophores, and visualization techniques, DMPs nanoparticles captured free iron sources in the environment, promoting algae growth by entering algal cells and facilitating the uptake and utilization of free iron ions from the solution. During the experiment, the iron uptake and transport genes (feoA and feoB) were significantly upregulated, whereas the algal siderophore synthesis gene (pchF) and the TonB-dependent transport system gene (TonB_C) were significantly downregulated, suggesting heightened activity in intracellular iron uptake and transport. This indicates an abundance of intracellular iron, eliminating the need for secrete siderophores to overcome iron deficiency. Microcystis aeruginosa increased iron bioavailability by using iron transported through DMPs in the environment while internalizing these DMPs. This study explored the mechanism of this synergistic effect to boost algal growth, and provided new ideas for elucidating the mechanism of cyanobacterial bloom outbreaks as well as the innovative application of biotechnology.

Purification and Characterization of Desferrioxamine B of Pseudomonas fluorescens and Its Application to Improve Oil Content, Nutrient Uptake, and Plant Growth in Peanuts.

Microorganisms produce siderophores, which are low-molecular-weight iron chelators when iron availability is limited. The present analyzed the role of LNPF1 as multifarious PGPR for improving growth parameters and nutrient content in peanut and soil nutrients. Such multifarious PGPR strains can be used as effective bioinoculants for peanut farming. In this work, rhizosphere bacteria from Zea mays and Arachis hypogaea plants in the Salem area of Tamil Nadu, India, were isolated and tested for biochemical attributes and characteristics that stimulate plant growth, such as the production of hydrogen cyanide, ammonia (6 µg/mL), indole acetic acid (76.35 µg/mL), and solubilizing phosphate (520 µg/mL). The 16S rRNA gene sequences identified the isolate LNPF1 as Pseudomonas fluorescens with a similarity percentage of 99% with Pseudomonas sp. Isolate LNPF1 was evaluated for the production of siderophore. Siderophore-rich supernatant using a Sep Pack C18 column and Amberlite-400 Resin Column (λmax 264) produced 298 mg/L and 50 mg/L of siderophore, respectively. The characterization of purified siderophore by TLC, HPLC, FTIR, and 2D-NMR analysis identified the compound as desferrioxamine, a hydroxamate siderophore. A pot culture experiment determined the potential of LNPF1 to improve iron and oil content and photosynthetic pigments in Arachis hypogaea L. and improve soil nutrient content. Inoculation of A. hypogea seeds with LNPF1 improved plant growth parameters such as leaf length (60%), shoot length (22%), root length (54.68%), fresh weight (47.28%), dry weight (37%), and number of nuts (66.66) compared to the control (untreated seeds). This inoculation also improved leaf iron content (43.42), short iron content (38.38%), seed iron (46.72%), seed oil (31.68%), carotenoid (64.40%), and total chlorophyll content (98.%) compared to control (untreated seeds). Bacterized seeds showed a substantial increase in nodulation (61.65%) and weight of individual nodules (95.97) vis-à-vis control. The results of the present study indicated that P. fluorescens might be utilized as a potential bioinoculant to improve growth, iron content, oil content, number of nuts and nodules of Arachishypogaea L., and enrich soil nutrients.

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.

Diagnostic Positron Emission Tomography Imaging with Zirconium-89 Desferrioxamine B Squaramide: From Bench to Bedside.

ConspectusMolecular imaging with antibodies radiolabeled with positron-emitting radionuclides combines the affinity and selectivity of antibodies with the sensitivity of Positron Emission Tomography (PET). PET imaging allows the visualization and quantification of the biodistribution of the injected radiolabeled antibody, which can be used to characterize specific biological interactions in individual patients. This characterization can provide information about the engagement of the antibody with a molecular target such as receptors present in elevated levels in tumors as well as providing insight into the distribution and clearance of the antibody. Potential applications of clinical PET with radiolabeled antibodies include identifying patients for targeted therapies, characterization of heterogeneous disease, and monitoring treatment response.Antibodies often take several days to clear from the blood pool and localize in tumors, so PET imaging with radiolabeled antibodies requires the use of a radionuclide with a similar radioactive half-life. Zirconium-89 is a positron-emitting radionuclide that has a radioactive half-life of 78 h and relatively low positron emission energy that is well suited to radiolabeling antibodies. It is essential that the zirconium-89 radionuclide be attached to the antibody through chemistry that provides an agent that is stable in vivo with respect to the dissociation of the radionuclide without compromising the biological activity of the antibody.This Account focuses on our research using a simple derivative of the bacterial siderophore desferrioxamine (DFO) with a squaramide ester functional group, DFO-squaramide (DFOSq), to link the chelator to antibodies. In our work, we produce conjugates with an average ∼4 chelators per antibody, and this does not compromise the binding of the antibody to the target. The resulting antibody conjugates of DFOSq are stable and can be easily radiolabeled with zirconium-89 in high radiochemical yields and purity. Automated methods for the radiolabeling of DFOSq-antibody conjugates have been developed to support multicenter clinical trials. Evaluation of several DFOSq conjugates with antibodies and low molecular weight targeting agents in tumor mouse models gave PET images with high tumor uptake and low background. The promising preclinical results supported the translation of this chemistry to human clinical trials using two different radiolabeled antibodies. The potential clinical impact of these ongoing clinical trials is discussed.The use of DFOSq to radiolabel relatively low molecular weight targeting molecules, peptides, and peptide mimetics is also presented. Low molecular weight molecules typically clear the blood pool and accumulate in target tissue more rapidly than antibodies, so they are usually radiolabeled with positron-emitting radionuclides with shorter radioactive half-lives such as fluorine-18 (t1/2 ∼ 110 min) or gallium-68 (t1/2 ∼ 68 min). Radiolabeling peptides and peptide mimetics with zirconium-89, with its longer radioactive half-life (t1/2 = 78 h), could facilitate the centralized manufacture and distribution of radiolabeled tracers. In addition, the ability to image patients at later time points with zirconium-89 based agents (e.g. 4-24 h after injection) may also allow the delineation of small or low-uptake disease sites as the delayed imaging results in increased clearance of the tracer from nontarget tissue and lower background signal.

Moving Beyond Isothiocyanates: A Look at the Stability of Conjugation Links Toward Radiolysis in 89Zr-Labeled Immunoconjugates.

Zirconium-89 is the most widely used radioisotope for immunoPET because its physical half-life (78.2 h) suits the one of antibodies. Desferrioxamine B (DFO) is the standard chelator for the complexation of zirconium(IV), and its bifunctional version, containing a phenylisothiocyanate function, is the most commonly used for the conjugation of DFO to proteins. However, preliminary results have shown that the thiourea link obtained from the conjugation of isothiocyanate and lysines is sensitive to the ionizing radiation generated by the radioisotope, leading to the rupture of the link and the release of the chelator/radiometal complex. This radiolysis phenomenon could produce nonspecific signal and prevent the detection of bone metastasis, as free zirconium accumulates into the bones. The aim of this work was to study the stability of a selection of conjugation linkers in 89Zr-labeled immunoconjugates. We have synthesized several DFO-based bifunctional chelators appended with an isothiocyanate moiety, a bicyclononyne, or a squaramate ester. Two antibodies (trastuzumab and rituximab) were conjugated and radiolabeled with zirconium-89. The effect of increasing activities of zirconium-89 on the integrity of the bioconjugate bearing thiourea links was evaluated as well as the impact of the presence of a radioprotectant. The stability of the radiolabeled antibodies was studied over 7 days in PBS and human plasma. Radioconjugates' integrity was evaluated using iTLC and size-exclusion chromatography. This study shows that the nature of the linker between the chelator and biomolecule can have a strong impact on the stability of the 89Zr-labeled conjugates, as well as on the aggregation of the conjugates.

MALDI-mass spectrometry imaging as a new technique for detecting non-heme iron in peripheral tissues via caudal vein injection of deferoxamine.

As one of the most common iron-chelating agents, deferoxamine (DFO) rapidly chelates iron in the body. Moreover, it does not compete for the iron characteristic of hemoglobin in the blood cells, which is common in the clinical treatment of iron poisoning. Iron is a trace element necessary to maintain organism normal life activities. Iron deficiency can lead to anemia, whereas iron overload can cause elevated levels of cellular oxidative stress and cell damage. As a consequence, detection of the iron content in tissues and blood is of great significance. The traditional techniques for detecting the iron content include inductively coupled plasma-mass spectrometry and atomic absorption spectrometry, which cannot be used for imaging purposes. Laser ablation-ICP-MS and synchrotron radiation micro-X-ray fluorescence can map the concentration and distribution of iron in tissues. However, these methods can only be used to measure the total iron levels in blood or tissues. In recent years, due to the deepening understanding of iron metabolism, diseases related to iron overload have attracted increasing attention. Therefore, we took advantage of the properties of DFO in terms of chelating iron and investigated different sampling times following DFO injection in the tail vein of mice. We used mass spectrometry imaging (MSI) technology to detect the DFO and ferrioxamine content in the blood and different tissues to indirectly characterize the non-heme iron content.

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

Patients with ß-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.

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.

Electrospun Biomimetic Periosteum Capable of Controlled Release of Multiple Agents for Programmed Promoting Bone Regeneration.

The effective repair of large bone defects remains a major challenge due to its limited self-healing capacity. Inspired by the structure and function of the natural periosteum, an electrospun biomimetic periosteum is constructed to programmatically promote bone regeneration using natural bone healing mechanisms. The biomimetic periosteum is composed of a bilayer with an asymmetric structure in which an aligned electrospun poly(ε-caprolactone)/gelatin/deferoxamine (PCL/GEL/DFO) layer mimics the outer fibrous layer of the periosteum, while a random coaxial electrospun PCL/GEL/aspirin (ASP) shell and PCL/silicon nanoparticles (SiNPs) core layer mimics the inner cambial layer. The bilayer controls the release of ASP, DFO, and SiNPs to precisely regulate the inflammatory, angiogenic, and osteogenic phases of bone repair. The random coaxial inner layer can effectively antioxidize, promoting cell recruitment, proliferation, differentiation, and mineralization, while the aligned outer layer can promote angiogenesis and prevent fibroblast infiltration. In particular, different stages of bone repair are modulated in a rat skull defect model to achieve faster and better bone regeneration. The proposed biomimetic periosteum is expected to be a promising candidate for bone defect healing.

Biosynthesis of novel desferrioxamine derivatives requires unprecedented crosstalk between separate NRPS-independent siderophore pathways.

Iron is essential to many biological processes but its poor solubility in aerobic environments restricts its bioavailability. To overcome this limitation, bacteria have evolved a variety of strategies, including the production and secretion of iron-chelating siderophores. Here, we describe the discovery of four series of siderophores from Streptomyces ambofaciens ATCC23877, three of which are unprecedented. MS/MS-based molecular networking revealed that one of these series corresponds to acylated desferrioxamines (acyl-DFOs) recently identified from S. coelicolor. The remaining sets include tetra- and penta-hydroxamate acyl-DFO derivatives, all of which incorporate a previously undescribed building block. Stable isotope labeling and gene deletion experiments provide evidence that biosynthesis of the acyl-DFO congeners requires unprecedented crosstalk between two separate non-ribosomal peptide synthetase (NRPS)-independent siderophore (NIS) pathways in the producing organism. Although the biological role(s) of these new derivatives remain to be elucidated, they may confer advantages in terms of metal chelation in the competitive soil environment due to the additional bidentate hydroxamic functional groups. The metabolites may also find application in various fields including biotechnology, bioremediation, and immuno-PET imaging.IMPORTANCEIron-chelating siderophores play important roles for their bacterial producers in the environment, but they have also found application in human medicine both in iron chelation therapy to prevent iron overload and in diagnostic imaging, as well as in biotechnology, including as agents for biocontrol of pathogens and bioremediation. In this study, we report the discovery of three novel series of related siderophores, whose biosynthesis depends on the interplay between two NRPS-independent (NIS) pathways in the producing organism S. ambofaciens-the first example to our knowledge of such functional cross-talk. We further reveal that two of these series correspond to acyl-desferrioxamines which incorporate four or five hydroxamate units. Although the biological importance of these novel derivatives is unknown, the increased chelating capacity of these metabolites may find utility in diagnostic imaging (for instance, 89Zr-based immuno-PET imaging) and other applications of metal chelators.