Hepcidin independent iron recycling in a mouse model of β‐thalassaemia intermedia

In conditions such as β‐thalassaemia, stimulated erythropoiesis can reduce the expression of the iron regulatory hormone hepcidin, increasing both macrophage iron release and intestinal iron absorption and leading to iron loading. However, in certain conditions, sustained elevation of erythropoiesis can occur without an increase in body iron load. To investigate this in more detail, we made use of a novel mouse strain (RBC14), which exhibits mild β‐thalassaemia intermedia with minimal iron loading. We compared iron homeostasis in RBC14 mice to that of Hbb^th3/+ mice, a more severe model of β‐thalassaemia intermedia. Both mouse strains showed a decrease in plasma iron half‐life, although the changes were less severe in RBC14 mice. Despite this, intestinal ferroportin and serum hepcidin levels were unaltered in RBC14 mice. In contrast, Hbb^th3/+ mice exhibited reduced serum hepcidin and increased intestinal ferroportin. However, splenic ferroportin levels were increased in both mouse strains. These data suggest that in low‐grade chronic haemolytic anaemia, such as that seen in RBC14 mice, the increased erythroid iron requirements can be met through enhanced macrophage iron release without the need to increase iron absorption, implying that hepcidin is not the sole regulator of macrophage iron release in vivo.     

Assessment and management of iron overload in β‐thalassaemia major patients during the 21st century: a real‐life experience from the Italian Webthal project

We conducted a cross‐sectional study on 924 β‐thalassaemia major patients (mean age 30·1 years) treated at nine Italian centres using the webthal software, to evaluate real‐life application of iron overload assessment and management standards. Serum ferritin <2500 ng/ml was a risk factor for never having liver iron concentration (LIC) measurement, while absence of cardiac disease and siderosis were risk factors for a delay in LIC measurement >2 years. Patients who never had a cardiac MRI (CMR) T2* measurement were <18 years, had iron intake ≤0·4 mg/kg per day, or a serum ferritin <2500 ng/ml. A history of normal CMR T2* was the main risk factor for a delay in subsequent assessment of >2 years. Deferoxamine (22·8%) was more commonly used in patients with Hepatitis C Virus or high serum creatinine. Deferiprone (20·6%) was less commonly prescribed in patients with elevated alanine aminotransferase; while a deferoxamine + deferiprone combination (17·9%) was more commonly used in patients with serum ferritin >2500 ng/ml or CMR T2* <20 ms. Deferasirox (38·3%) was more commonly prescribed in patients <18 years, but less commonly used in those with heart disease or high iron intake. These observations largely echoed guidelines at the time, although some practices are expected to change in light of evolving evidence.     

No evidence for myocardial iron overload and free iron species in multitransfused patients with sickle/β0‐thalassaemia

Iron overload (IO) in the heart is a life‐threatening complication in transfusion‐dependent patients with thalassaemia major (TM) and to a lesser extent in sickle cell disease (SCD), while no data are available in patients with sickle/β⁰‐thalassaemia. Iron deposition in the heart, liver and pancreas was assessed using T2* MRI sequences, as well as free iron species assays – non‐transferrin bound iron (NTBI) and labile plasma iron (LPI), in addition to serum ferritin, percentage transferrin saturation and serum hepcidin, in 10 multitransfused patients (>30 yr) with sickle/β⁰‐thalassaemia. None of the patients had iron deposition in the heart. Three patients had mild, one had moderate, and two had severe liver IO. Two patients had mild iron deposition in the pancreas. In all the patients, serum hepcidin levels were normal – NTBI and LPI were not detected. Possible explanations of these findings are discussed.     

Elevated serum parathormone levels are associated with myocardial iron overload in patients with β‐thalassaemia major

Objectives: Despite advances in conventional treatment, iron‐induced cardiomyopathy is still the most frequent cause of death among patients with β‐thalassaemia major. Recent studies have correlated increased myocardial iron content to decreased levels of vitamin D in thalassaemic patients. The aim of this study was to measure parathormone (PTH) and metabolites of vitamin D and consequently to investigate whether these parameters predispose to myocardial iron overload in patients with β‐thalassaemia major. Methods: In 62 patients (29 M and 33 F, mean age: 22.79 ± 6.18 yr) with β‐thalassaemia major levels of intact parathormone (iPTH) and vitamin D metabolites [25(ΟH)D₃ and 1,25(ΟH)₂D₃] were measured in serum. Additionally, estimation of myocardial iron content was performed by magnetic resonance imaging, whereas mean serum ferritin concentrations were calculated for 1 yr prior to the study. Results: Results showed markedly decreased levels of serum 25(OH)D₃ in 37 patients (60%), whereas 7 patients (11%) had borderline 25(OH)D₃ levels (between 50 and 75 nmol/L). Serum iPTH levels were significantly higher in patients having increased myocardial iron compared to those having normal myocardial iron (44.04 ± 22.09 pg/mL vs. 31.39 ± 14.30 pg/mL, P = 0.017). Multivariant regression analysis identified PTH levels as the major predictor of increased myocardial iron.     

Periplogenin‐3‐O‐ ‐D‐Glucopyranosyl ‐(1→6)‐ ‐D‐Glucopyaranosyl‐ ‐(1→4) ‐D‐Cymaropyranoside,Isolated from Aegle marmelos Protects Doxorubicin Induced Cardiovascular Problems and Hepatotoxicity in Rats

Doxorubicin is a common chemotherapeutic anticancer drug. Its use is associated with adverse effects including cardiotoxicity. Several therapeutics interventions have been attempted to reduce the toxicity and to improve the efficacy of the drug. However, on phytochemicals very few investigations have been made. In the present study we have evaluated the potential of a cardenolide, periplogenin, isolated from the leaves of Aegle marmelos in protecting the doxorubicin induced cardiotoxicity and lipid peroxidation (LPO) in rats. Doxorubicin induced cardiac and hepatotoxicity were characterized by marked biochemical changes including an increase in serum creatine kinase–MB (CK–MB), glutamate‐pyruvate transaminase (SGPT), and tissue LPO, with a decrease in superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). It also increased the levels of different serum lipids, but decreased the amount of high‐density lipoprotein (HDL). Cotherapy of the test cardenolide and doxorubicin for 4 weeks reversed all these adverse effects. However, out of three different concentrations (12.5, 25, and 50 mg/kg p.o.) of the test periplogenin, 25 mg/kg appeared to be most effective. When its efficacy was compared with that of vitamin E (α‐tocopherol) the isolated compound exhibited a better therapeutic potential. The isolated periplogenin from the leaves of A. marmelos could potentially inhibit doxorubicin‐induced cardiovascular problems in rats. However, its moderate dose was found to be most effective.     

Analysis of N1‐acetyl‐N2‐formyl‐5‐methoxykynuramine/N1‐acetyl‐5‐methoxy‐kynuramine formation from melatonin in mice

Abstract: The interactions of melatonin, a potent endogenous antioxidant, with reactive oxygen species generate several products that include N¹‐acetyl‐N²‐formyl‐5‐methoxykynuramine (AFMK) and N¹‐acetyl‐5‐methoxy‐kynuramine (AMK). The physiological or pathological significance of AFMK/AMK formation during the process of melatonin metabolism in mammals has not been clarified. Using a metabolomic approach in the current study, the AFMK/AMK pathway was thoroughly investigated both in mice and humans. Unexpectedly, AFMK and AMK were not identified in the urine of humans nor in the urine, feces or tissues (including liver, brain, and eyes) in mice under the current experimental conditions. Metabolomic analysis did identify novel metabolites of AMK, i.e. hydroxy‐AMK and glucuronide‐conjugated hydroxy‐AMK. These two newly identified metabolites were, however, not found in the urine of humans. In addition, oxidative stress induced by acetaminophen in the mouse model did not boost AFMK/AMK formation. These data suggest that AFMK/AMK formation is not a significant pathway of melatonin disposition in mice, even under conditions of oxidative stress.     

Electrocardiographic Presentation,Cardiac Arrhythmias,and Their Management in β‐Thalassemia Major Patients

Beta‐thalassemia major (β‐TM) is a genetic hemoglobin disorder characterized by an absent synthesis of globin chains that are essential for hemoglobin formation, causing chronic hemolytic anemia. Clinical management of thalassemia major consists in regular long‐life red blood cell transfusions and iron chelation therapy to remove iron introduced in excess with transfusions. Iron deposition in combination with inflammatory and immunogenic factors is involved in the pathophysiology of cardiac dysfunction in these patients. Heart failure and arrhythmias, caused by myocardial siderosis, are the most important life‐limiting complications of iron overload in beta‐thalassemia patients. Cardiac complications are responsible for 71% of global death in the beta‐thalassemia major patients. The aim of this review was to describe the most frequent electrocardiographic abnormalities and arrhythmias observed in β‐TM patients, analyzing their prognostic impact and current treatment strategies.     

Urine biochemical markers of early renal dysfunction are associated with iron overload in β‐thalassaemia

Summary Renal dysfunction in thalassemia patients can be attributed to chronic anemia, and iron overload as well as to desferioxamine (DFO) toxicity. We analyzed the urine of 91 well‐maintained homozygous β‐thalassemia patients, with no evidence of renal disease, for early evidence of kidney dysfunction by means of electrophoresis and quantitative biochemical tests. Measurement of liver magnetic resonance imaging (MRI) T2 values and serum ferritin concentration was used to estimate iron overload. In 55 of the 91 patients, urine analysis indicated signs of tubular dysfunction. The urine concentration of albumin and beta 2‐microglobulin, as well as the activity of n ‐acetyl‐beta‐d ‐glucosaminidase (NAG), correlated positively with serum ferritin concentration and liver iron deposition, as detected by MRI T2 values. This suggested that the cause of renal dysfunction in homozygous β‐thalassemia is iron overload. On the other hand, the same urine markers did not correlate with age, indicating that chronic anemia or desferrioxamine (DFO) treatment are not related to renal dysfunction in thalassemia.     

Deferasirox effect on renal haemodynamic parameters in patients with transfusion‐dependent β thalassaemia

Some patients with β thalassaemia experience non‐progressive creatinine increases with deferasirox, mostly within normal limits; the mechanisms involved are not fully elucidated. The effects of deferasirox on renal haemodynamics, including glomerular filtration rate (GFR) and renal plasma flow (RPF), were investigated in a Phase I, open‐label study in β thalassaemia major patients with iron overload. Patients received deferasirox 30 mg/kg/d up to Week 8, followed by a 2‐week washout period, and extended treatment up to Week 104 with a 4‐week washout period. In the short‐term study (n = 11), mean GFR and RPF declined from baseline to Week 8 (mean [%] change:?9·2 [?9·5%] and ?105·7 ml/min [?17·8%], respectively). A similar pattern was observed during the long‐term study (n = 5); mean GFR and RPF decreased up to Week 52 (?19·1 [?17·7%] and ?155·6 ml/min [?26·1%]), with similar change at Week 104 (?18·4 [?17·2%] and ?115·9 ml/min [?19·6%]). Measures returned to baseline values after each washout. Serum creatinine and creatinine clearance followed a similar pattern. Effects of deferasirox on renal haemodynamics were mild and reversible for up to 2 years of treatment, with no progressive worsening of renal function over time. www.clinicaltrials.gov : NCT00560820.