Iron-mediated tissue damage in acquired ineffective erythropoiesis disease: It’s more a matter of burden or more of exposure to toxic iron form?

Structural analysis and bioavailability study of low-molecular-weight chondroitin sulfate‑iron complexes prepared by photocatalysis-Fenton reaction

Increasing studies focus on depolymerization of chondroitin sulfate (CS) to enhance its biological activities. In the present study, low-molecular-weight chondroitin sulfate (LMWCS)‑iron complexes were obtained by photocatalysis-Fenton reaction. After degradation with the optimal condition of 0.25 % (w/v) TiO2, 10 mM FeSO4, and 400 mM H2O2 for 0, 15, and 60 min, the average relative molecular weights of CS were reduced to 4.77, 2.47, and 1.21 kDa, respectively. Electron paramagnetic resonance and free radical capture test identified •OH, •O2-, and h+ in the photocatalysis-Fenton system, among them h+ was the major contributor for CS degradation. The structures of degradation products were analyzed by UV, CD, XRD, SEM-EDS, and NMR, and the results indicated that CS chelated iron with its carboxyl and sulfate groups, leading to changes in conformation and microtopography. Then 10 oligosaccharides were identified in the degradation products using HPLC-MSn and the depolymerization mechanism was proposed. Furthermore, iron release was observed in simulated gastrointestinal digestion of LMWCS‑iron complexes. Notably, the everted gut sac experiment demonstrated that LMWCS‑iron complex possessed 3.75 times higher iron absorption than FeSO4 (p < 0.01) and 12.60 times higher CS absorption than original CS (p < 0.0001). In addition, LMWCS‑iron exhibited stronger in vitro antioxidant activity than CS.

Effect of Aging on Deferasirox Therapy in Transfusion-dependent Patients. A Prospective- Retrospective, Cohort-study

BACKGROUND

Iron-chelation therapy is life-saving in patients on a chronic transfusion regimen as it reduces organ damage related to iron deposition in the tissues. Deferasirox, an iron-chelator, is characterized by pharmacokinetics variability, and some patients may discontinue the treatment due to toxicities.

OBJECTIVE

Understanding whether deferasirox plasma levels are related to patients' specific characteristics could help to optimize DFX dosage.

METHODS

We analyzed deferasirox plasma concentration in 57 transfusion-dependent anemic patients using the HPLC method in this prospective-retrospective cohort study. All outpatients (3 to 98 years) were treated with deferasirox (film-coated tablet) for at least one year (median dose, 16.5 mg/Kg once a day). Deferasirox plasma concentration was normalized for dose/Kg (C/dose) and corrected with a linear regression model that relates C/dose and the time of blood sampling (Cref/dose).

RESULTS

No significant differences in Cref/dose were found between males and females, either between different types of hemoglobinopathies or depending on the presence of the UGT1A1*28 polymorphism. Cref/dose has a positive and significant correlation with age, creatinine, and direct bilirubin. Cref/dose, instead, has a negative and significant correlation with Liver Iron Concentration (LIC), ferritin, and eGFR. Cref/dose was significantly different between three age categories <18yrs, 18-50yrs, and >50yrs, with Cref/dose median values of 1.0, 1.2, and 1.5, respectively.

CONCLUSION

The study evidenced that to ensure the efficacy of deferasirox in terms of control over LIC and, at the same time, a lesser influence on renal function, the dose of the drug to be administered to an elderly patient could be reduced.