Selective ferroptosis vulnerability due to familial Alzheimer's disease presenilin mutations

Mutations in presenilin 1 and 2 (PS1 and PS2) cause autosomal dominant familial Alzheimer's disease (FAD). Ferroptosis has been implicated as a mechanism of neurodegeneration in AD since neocortical iron burden predicts Alzheimer's disease (AD) progression. We found that loss of the presenilins dramatically sensitizes multiple cell types to ferroptosis, but not apoptosis. FAD causal mutations of presenilins similarly sensitizes cells to ferroptosis. The presenilins promote the expression of GPX4, the selenoprotein checkpoint enzyme that blocks ferroptosis by quenching the membrane propagation of lethal hydroperoxyl radicals. Presenilin gamma-secretase activity cleaves Notch-1 to signal LRP8 expression, which then controls GPX4 expression by regulating the supply of selenium into the cell since LRP8 is the uptake receptor for selenoprotein P. Selenium uptake is thus disrupted by presenilin FAD mutations, suppressing GPX4 expression. Therefore, presenilin mutations may promote neurodegeneration by derepressing ferroptosis, which has implications for disease-modifying therapeutics.Peer reviewe

Identifying chondroprotective diet-derived bioactives and investigating their synergism

Osteoarthritis (OA) is a multifactorial disease and nutrition is a modifiable factor that may contribute to disease onset or progression. A detailed understanding of mechanisms through which diet-derived bioactive molecules function and interact in OA is needed. We profiled 96 diet-derived, mainly plant-based bioactives using an in vitro model in chondrocytes, selecting four candidates for further study. We aimed to determine synergistic interactions between bioactives that affected the expression of key genes in OA. Selected bioactives, sulforaphane, apigenin, isoliquiritigenin and luteolin, inhibited one or more interleukin-1-induced metalloproteinases implicated in OA (MMP1, MMP13, ADAMTS4, ADAMTS5). Isoliquiritigenin and luteolin showed reactive oxygen species scavenging activity in chondrocytes whereas sulforaphane had no effect and apigenin showed only a weak trend. Sulforaphane inhibited the IL-1/NFκB and Wnt3a/TCF/Lef pathways and increased TGFβ/Smad2/3 and BMP6/Smad1/5/8 signalling. Apigenin showed potent inhibition of the IL-1/NFκB and TGFβ/Smad2/3 pathways, whereas luteolin showed only weak inhibition of the IL-1/NFκB pathway. All four bioactives inhibited cytokine-induced aggrecan loss from cartilage tissue explants. The combination of sulforaphane and isoliquiritigenin was synergistic for inhibiting MMP13 gene expression in chondrocytes. We conclude that dietary-derived bioactives may be important modulators of cartilage homeostasis and synergistic relationships between bioactives may have an anti-inflammatory and chondroprotective role

Absence of an effect of a single-dose deferasirox on the steady-state pharmacokinetics of digoxin.

Deferasirox (Exjade, ICL670) is a potent iron chelator, recently approved as first-line therapy for the treatment of blood-transfusion-related iron overload. Iron deposition in the heart may lead to cardiac dysfunction in patients with iron overload. Thus, the combination of cardiac glycosides and deferasirox is likely to be used in clinical practice

Relative bioavailability of deferasirox tablets administered without dispersion and dispersed in various drinks.

Deferasirox (ExjadeA, ICL670) is a new, once-daily oral iron chelator, recently approved as first-line therapy in the treatment of iron overload resulting from blood transfusions. In registration studies, deferasirox tablets were dispersed in non-carbonated water prior to administration. In routine clinical practice, however, patients may prefer to take the tablet dispersed in a flavored drink rather than with water

Pharmacokinetics and variability of mycophenolic acid from enteric-coated mycophenolate sodium compared with mycophenolate mofetil in de novo heart transplant recipients

Sequential pharmacokinetic assessments were performed at five centers within the context of a multicenter, single-blind, randomized clinical trial comparing the efficacy and safety of enteric-coated mycophenolate sodium (EC-MPS, myfortic) and mycophenolate mofetil (MMF, CellCept) in de novo heart transplant recipients. Patients were randomized to either EC-MPS 1080 mg bid or MMF 1500 mg bid, as part of a triple immunosuppressive therapy including cyclosporine microemulsion. Steady-state pharmacokinetic profiles of mycophenolic acid (MPA) and its inactive phenolic glucuronide (MPAG) were assessed at weeks 2, 12, and 52. Pharmacokinetic parameters were evaluated in 32 patients (17 on EC-MPS and 15 on MMF). Dose-normalized peak (C(max,ss)) and area under the curve (AUC(tau,ss)) of MPA and MPAG increased between week 2 and week 12 assessments for both treatments. Comparisons between EC-MPS and MMF showed no statistically significant differences in MPA and MPAG AUC(tau,ss), C(max,ss), and trough (C(min,ss)) values (p-values ranged from 0.225 to 0.990). Consistent with the delayed release characteristics of EC-MPS, C(max,ss) occurred approximately one hour later compared with MMF. Inter-subject coefficients of variation (%CV) for MPA pharmacokinetic parameters of both EC-MPS and MMF were high (37-72% for AUC(tau,ss) at weeks 2 and 12). Also within patients, the pharmacokinetics of MPA varied considerably. Specifically, intra-subject %CVs for MPA AUC(tau,ss), C(max,ss), and C(min,ss) were 28%, 63%, and 34% with EC-MPS and 54%, 139%, and 41% with MMF respectively. These results indicate that a dose of EC-MPS 1080 mg bid in combination with cyclosporine provides adequate systemic MPA exposure in de novo heart transplant patients, comparable with MMF 1500 mg bid. Overall, there is a large inter- and intra-subject variability in MPA pharmacokinetic parameters with both treatments

Effect of Food, Type of Food, and Time of Food Intake on Deferasirox (Exjade®, ICL670) Bioavailability – Recommendations for an Optimal Deferasirox Administration Regimen

Deferasirox (ICL670) is representative of a new class of tridentate iron chelators, formulated as tablets for dispersion. Deferasirox has exhibited high potency and a clinically manageable safety profile in preclinical models and in an extensive clinical program. The effect of food and time of food intake on the pharmacokinetics of deferasirox was investigated in healthy volunteers and patients with transfusional hemosiderosis. The bioequivalence of a single oral dose of deferasirox (20 mg/kg) was assessed following administration either before a high-fat or standard breakfast or concurrent with a standard breakfast in comparison with fasted conditions in healthy volunteers. The bioavailability of deferasirox was determined following a single oral dose (20 mg/kg) under fed and fasted conditions in patients. These data show that the type of food, caloric content, and fat content of the meal influence the bioavailability of deferasirox when consumed concomitantly. In contrast, this is not the case when deferasirox is administered at least 30 minutes before a meal. In conclusion, it is recommended that deferasirox be administered at least 30 minutes prior to meals. When this is not feasible, deferasirox should be administered consistently at the same time before meals to limit the sources of variability that affect absorption

Effect of food, type of food, and time of food intake on deferasirox bioavailability : recommendations for an optimal deferasirox administration regimen

Deferasirox (ICL670) is representative of a new class of tridentate iron chelators, formulated as tablets for dispersion. Deferasirox has exhibited high potency and a clinically manageable safety profile in preclinical models and in an extensive clinical program. The effect of food and time of food intake on the pharmacokinetics of deferasirox was investigated in healthy volunteers and patients with transfusional hemosiderosis. The bioequivalence of a single oral dose of deferasirox (20 mg/kg) was assessed following administration either before a high-fat or standard breakfast or concurrent with a standard breakfast in comparison with fasted conditions in healthy volunteers. The bioavailability of deferasirox was determined following a single oral dose (20 mg/kg) under fed and fasted conditions in patients. These data show that the type of food, caloric content, and fat content of the meal influence the bioavailability of deferasirox when consumed concomitantly. In contrast, this is not the case when deferasirox is administered at least 30 minutes before a meal. In conclusion, it is recommended that deferasirox be administered at least 30 minutes prior to meals. When this is not feasible, deferasirox should be administered consistently at the same time before meals to limit the sources of variability that affect absorption

Viral-free generation and characterization of a human induced pluripotent stem cell line from dermal fibroblasts

Peripheral dermal fibroblasts (DF) from a healthy 56 year old female were obtained from the Centre for Healthy Brain Ageing (CHeBA) Biobank, University of New South Wales, under the material transfer agreement with the University of Wollongong. DFs were reprogrammed via mRNA-delivered transcription factors into induced pluripotent stem cells (iPSCs). The generated iPSCs were confirmed to be pluripotent, capable of three germ layer differentiation and are thus a useful resource for creating iPSC-derived healthy human cells of any lineage. Resource table [Table presented