Incidence and Risk Factors for Development of Cardiac Toxicity in Adult Patients with Newly Diagnosed Acute Myeloid Leukemia.

The incidence of cardiac morbimortality in acute myeloid leukemia (AML) is not well known. We aim to estimate the cumulative incidence (CI) of cardiac events in AML patients and to identify risk factors for their occurrence. Among 571 newly diagnosed AML patients, 26 (4.6%) developed fatal cardiac events, and among 525 treated patients, 19 (3.6%) experienced fatal cardiac events (CI: 2% at 6 months; 6.7% at 9 years). Prior heart disease was associated with the development of fatal cardiac events (hazard ratio (HR) = 6.9). The CI of non-fatal cardiac events was 43.7% at 6 months and 56.9% at 9 years. Age ≥ 65 (HR = 2.2), relevant cardiac antecedents (HR = 1.4), and non-intensive chemotherapy (HR = 1.8) were associated with non-fatal cardiac events. The 9-year CI of grade 1-2 QTcF prolongation was 11.2%, grade 3 was 2.7%, and no patient had grade 4-5 events. The 9-year CI of grade 1-2 cardiac failure was 1.3%, grade 3-4 was 15%, and grade 5 was 2.1%; of grade 1-2, arrhythmia was 1.9%, grade 3-4 was 9.1%, and grade 5 was 1%. Among 285 intensive therapy patients, median overall survival decreased in those experiencing grade 3-4 cardiac events (p < 0.001). We observed a high incidence of cardiac toxicity associated with significant mortality in AML.

Nitric oxide is essential for cadmium-induced peroxule formation and peroxisome proliferation.

Nitric oxide (NO) and nitrosylated derivatives are produced in peroxisomes, but the impact of NO metabolism on organelle functions remains largely uncharacterised. Double and triple NO-related mutants expressing cyan florescent protein (CFP)-SKL (nox1 × px-ck and nia1 nia2 × px-ck) were generated to determine whether NO regulates peroxisomal dynamics in response to cadmium (Cd) stress using confocal microscopy. Peroxule production was compromised in the nia1 nia2 mutants, which had lower NO levels than the wild-type plants. These findings show that NO is produced early in the response to Cd stress and was involved in peroxule production. Cd-induced peroxisomal proliferation was analysed using electron microscopy and by the accumulation of the peroxisomal marker PEX14. Peroxisomal proliferation was inhibited in the nia1 nia2 mutants. However, the phenotype was recovered by exogenous NO treatment. The number of peroxisomes and oxidative metabolism were changed in the NO-related mutant cells. Furthermore, the pattern of oxidative modification and S-nitrosylation of the catalase (CAT) protein was changed in the NO-related mutants in both the absence and presence of Cd stress. Peroxisome-dependent signalling was also affected in the NO-related mutants. Taken together, these results show that NO metabolism plays an important role in peroxisome functions and signalling.

Cadmium induces reactive oxygen species-dependent pexophagy in Arabidopsis leaves.

Cadmium treatment induces transient peroxisome proliferation in Arabidopsis leaves. To determine whether this process is regulated by pexophagy and to identify the mechanisms involved, we analysed time course-dependent changes in ATG8, an autophagy marker, and the accumulation of peroxisomal marker PEX14a. After 3 hr of Cd exposure, the transcript levels of ATG8h, ATG8c, a, and i were slightly up-regulated and then returned to normal. ATG8 protein levels also increased after 3 hr of Cd treatment, although an opposite pattern was observed in PEX14. Arabidopsis lines expressing GFP-ATG8a and CFP-SKL enabled us to demonstrate the presence of pexophagic processes in leaves. The Cd-dependent induction of pexophagy was demonstrated by the accumulation of peroxisomes in autophagy gene (ATG)-related Arabidopsis knockout mutants atg5 and atg7. We show that ATG8a colocalizes with catalase and NBR1 in the electron-dense peroxisomal core, thus suggesting that NBR1 may be an autophagic receptor for peroxisomes, with catalase being possibly involved in targeting pexophagy. Protein carbonylation and peroxisomal redox state suggest that protein oxidation may trigger pexophagy. Cathepsine B, legumain, and caspase 6 may also be involved in the regulation of pexophagy. Our results suggest that pexophagy could be an important step in rapid cell responses to cadmium.

Fontan Circulation in Adult Patients: Acoustic Radiation Force Impulse Elastography as a Useful Tool for Liver Assessment.

OBJECTIVE: The development of liver fibrosis and cirrhosis due to long-standing liver congestion is known to occur in adult patients with Fontan circulation. Hepatic elastography has shown to be a useful tool for the noninvasive assessment and staging of liver fibrosis in chronic liver diseases, although the utility of this technique in Fontan patients remains to be adequately studied. METHODS: Twenty-one patients with Fontan circulation underwent an abdominal ultrasound and an acoustic radiation force impulse (ARFI) elastography. In order to compare the results from this group, a cohort of 14 healthy controls and another group containing 17 patients with cirrhosis were included. The association between the velocity values measured with elastography and clinical and analytical parameters were also studied. RESULTS: Mean shear waves propagation velocity in liver tissue in the Fontan group was 1.86 ± 0.5 m/s, with 76% of patients over the cirrhosis threshold (1.55 m/s). The control group had a mean velocity of 1.09 ± 0.06 m/s, while the cirrhotic group obtained 2.71 ± 0.51 m/s. Seven patients with Fontan circulation had increased liver enzymes. Liver ultrasound showed evidence of chronic liver disease in six patients. Velocity values obtained in the presence or absence of analytical or liver ultrasound abnormalities showed significant differences in the univariate analysis (P = .04 and P = .03 respectively). CONCLUSION: In conclusion, ARFI elastography showed increased wave propagation velocity values in the Fontan population suggesting increased liver stiffness which could be related to advanced fibrosis. A statistically significant association between ARFI values and the presence of analytical and ultrasound abnormalities has been demonstrated.

Cadmium induces two waves of reactive oxygen species in Glycine max (L.) roots.

Cadmium (Cd) is a non-essential heavy metal that may be toxic or even lethal to plants as it can be easily taken up by the roots and loaded into the xylem to the leaves. Using soybean roots (Glycine max L.) DM 4800, we have analysed various parameters related to reactive oxygen metabolism and nitric oxide (NO) during a 6 day Cd exposure. A rise in H(2)O(2) and NO, and to a lesser extent O(2)(·-) content was observed after 6 h exposure with a concomitant increase in lipid peroxidation and carbonyl group content. Both oxidative markers were significantly reduced after 24 h. A second, higher wave of O(2)(·-) production was also observed after 72 h of exposure followed by a reduction until the end of the treatment. NOX and glicolate oxidase activity might be involved in the initial Cd-induced reactive oxygen species (ROS) production and it appears that other sources may also participate. The analysis of antioxidative enzymes showed an increase in glutathione-S-transferase activity and in transcript levels and activity of enzymes involved in the ascorbate-glutathione cycle and the NADPH-generating enzymes. These results suggest that soybean is able to respond rapidly to oxidative stress imposed by Cd by improving the availability of NADPH necessary for the ascorbate-glutathione cycle.

Epigenetic changes accompany developmental programmed cell death in tapetum cells.

The tapetum, the nursing tissue inside anthers, undergoes cellular degradation by programmed cell death (PCD) during late stages of microspore-early pollen development. Despite the key function of tapetum, little is known about the molecular mechanisms regulating this cell death process in which profound nuclear and chromatin changes occur. Epigenetic features (DNA methylation and histone modifications) have been revealed as hallmarks that establish the functional status of chromatin domains, but no evidence on the epigenetic regulation of PCD has been reported. DNA methylation is accomplished by DNA methyltransferases, among which DNA methyl transferase 1 (MET1) constitutes one of the CG maintenance methyltransferase in plants, also showing de novo methyltransferase activity. In this work, the changes in epigenetic marks during the PCD of tapetal cells have been investigated by a multidisciplinary approach to reveal the dynamics of DNA methylation and the pattern of expression of MET1 in relation to the main cellular changes of this PCD process which have also been characterized in two species, Brassica napus and Nicotiana tabacum. The results showed that tapetum PCD progresses with the increase in global DNA methylation and MET1 expression, epigenetic changes that accompanied the reorganization of the nuclear architecture and a high chromatin condensation, activity of caspase 3-like proteases and Cyt c release. The reported data indicate a relationship between the PCD process and the DNA methylation dynamics and MET1 expression in tapetal cells, suggesting a possible new role for the epigenetic marks in the nuclear events occurring during this cell death process and providing new insights into the epigenetic control of plant PCD.

Differential response of young and adult leaves to herbicide 2,4-dichlorophenoxyacetic acid in pea plants: role of reactive oxygen species.

In this work the differential response of adult and young leaves from pea (Pisum sativum L.) plants to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) (23 mm) applied by foliar spraying was investigated. The concentration of 2,4-D (23 mm) and the time of treatment (72 h) were previously optimized in order to visualize its toxic effects on pea plants. Under these conditions, the herbicide induced severe disturbances in mesophyll cells structure and proliferation of vascular tissue in young leaves and increased acyl-CoA oxidase (ACX), xanthine oxidase (XOD) and lipoxygenase (LOX) activities in young leaves, and only ACX and LOX in adult leaves. This situation produced reactive oxygen species (ROS) over-accumulation favoured by the absence of significant changes in the enzymatic antioxidants, giving rise to oxidative damages to proteins and membrane lipids. An increase of ethylene took place in both young and adult leaves and the induction of genes encoding the stress proteins, PRP4A and HSP 71,2, was observed mainly in young leaves. These results suggest that ROS overproduction is a key factor in the effect of high concentrations of 2,4-D, and ROS can trigger a differential response in young and adult leaves, either epinasty development in young leaves or senescence processes in adult tissues.

Peroxisome dynamics in Arabidopsis plants under oxidative stress induced by cadmium.

Peroxisomes are organelles with an essentially oxidative metabolism that are involved in various metabolic pathways such as fatty acid beta-oxidation, photorespiration, and metabolism of reactive oxygen species (ROS) and reactive nitrogen species. These organelles are highly dynamic but there is little information about the regulation of, and the effects of environment on, peroxisome movement. In this work a stable Arabidopsis line expressing the GFP-SKL peptide targeted to peroxisomes was characterized. Peroxisome-associated fluorescence was observed in all tissues, including leaves (mesophyll and epidermal cells, trichomes, and stomata) and roots. The dynamics of peroxisomes in epidermal cells was examined by confocal laser microscope, and various types of movement were observed. The speed of movement differed depending on the plant age. Treatment of plants with CdCl(2) (100 microM) produced a significant increase in speed, which was dependent on endogenous ROS and Ca(2+), but was not related to actin cytoskeleton modifications. In light of the results obtained, it is proposed that the increase in peroxisomal motility observed in Arabidopsis plants could be a cellular mechanism of protection against the Cd-imposed oxidative stress. Other possible roles for the enhanced peroxisome movement in plant cell physiology are discussed.

Cellular response of pea plants to cadmium toxicity: cross talk between reactive oxygen species, nitric oxide, and calcium.

Cadmium (Cd) toxicity has been widely studied in different plant species; however, the mechanism involved in its toxicity as well as the cell response against the metal have not been well established. In this work, using pea (Pisum sativum) plants, we studied the effect of Cd on antioxidants, reactive oxygen species (ROS), and nitric oxide (NO) metabolism of leaves using different cellular, molecular, and biochemical approaches. The growth of pea plants with 50 mum CdCl(2) affected differentially the expression of superoxide dismutase (SOD) isozymes at both transcriptional and posttranscriptional levels, giving rise to a SOD activity reduction. The copper/zinc-SOD down-regulation was apparently due to the calcium (Ca) deficiency induced by the heavy metal. In these circumstances, the overproduction of the ROS hydrogen peroxide and superoxide could be observed in vivo by confocal laser microscopy, mainly associated with vascular tissue, epidermis, and mesophyll cells, and the production of superoxide radicals was prevented by exogenous Ca. On the other hand, the NO synthase-dependent NO production was strongly depressed by Cd, and treatment with Ca prevented this effect. Under these conditions, the pathogen-related proteins PrP4A and chitinase and the heat shock protein 71.2, were up-regulated, probably to protect cells against damages induced by Cd. The regulation of these proteins could be mediated by jasmonic acid and ethylene, whose contents increased by Cd treatment. A model is proposed for the cellular response to long-term Cd exposure consisting of cross talk between Ca, ROS, and NO.

Differential expression and regulation of antioxidative enzymes by cadmium in pea plants.

The long-term effects of 50 microM CdCl(2) on the enzymatic and non-enzymatic antioxidative defences of pea (Pisum sativum L.) plants was studied in terms of activity, protein content and transcripts levels. Cadmium caused a reduction of the total glutathione content (GSH+GSSG), with the reduced form of glutathione (GSH) being most affected. The content of ascorbic acid (ASC) was also decreased by the treatment. The transcript levels of catalase (CAT) and monodehydroascorbate reductase (MDHAR) showed a Cd-dependent increase, although CAT activity and its protein content were depressed, which suggests a posttranslational modification of this protein induced by cadmium. Glutathione reductase (GR), and ascorbate peroxidase (APX) did not change significantly, either in activity or accumulation of transcript. However, cadmium treatment provoked a strong reduction in mRNA, protein level and activity of CuZn-superoxide dismutase (SOD), being the most negatively affected antioxidative enzyme, and in less extent of Mn-SOD. Transcriptome analysis of the antioxidative enzymes in leaves of pea plants grown with cadmium and treated with some modulators of the signal transduction cascade suggested that at least Ca(2+) channels, phosphorylation/dephosphorylation processes, nitric oxide, cGMP, salicylic acid (SA) and H(2)O(2) were involved in some steps between the cadmium signal and transcript expression of CuZn-SOD, CAT and MDHAR. This indicated the existence of cross-talk between these elements and reactive oxygen species (ROS) metabolism during cadmium stress.

Cadmium effect on oxidative metabolism of pea (Pisum sativum L.) roots. Imaging of reactive oxygen species and nitric oxide accumulation in vivo.

Growth of pea (Pisum sativum L.) plants with 50 microM CdCl2 for 15 d produced a reduction in the number and length of lateral roots, and changes in structure of the principal roots affecting the xylem vessels. Cadmium induced a reduction in glutathione (GSH) and ascorbate (ASC) contents, and catalase (CAT), GSH reductase (GR) and guaiacol peroxidase (GPX) activities. CuZn-superoxide dismutase (SOD) activity was also diminished by the Cd treatment, although Mn-SOD was slightly increased. CAT and CuZn-SOD were down-regulated at transcriptional level, while Mn-SOD, Fe-SOD and GR were up-regulated. Analysis of reactive oxygen species (ROS) and nitric oxide (NO) levels by fluorescence and confocal laser microscopy (CLM) showed an over-accumulation of O2*- and H2O2, and a reduction in the NO content in lateral and principal roots. ROS overproduction was dependent on changes in intracellular Ca+2 content, and peroxidases and NADPH oxidases were involved. Cadmium also produced an increase in salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) contents. The rise of ET and ROS, and the NO decrease are in accordance with senescence processes induced by Cd, and the increase of JA and SA could regulate the cellular response to cope with damages imposed by cadmium.

Localization of S-nitrosoglutathione and expression of S-nitrosoglutathione reductase in pea plants under cadmium stress.

S-nitrosoglutathione (GSNO) is considered a natural nitric oxide (NO.) reservoir and a reactive nitrogen intermediate in animal cells, but little is known about this molecule and its metabolism in plant systems. In this work, using pea plants as a model system, the presence of GSNO in collenchyma cells was demonstrated by an immunohistochemical method. When pea plants were grown with a toxic Cd concentration (50 microM) the content of GSNO in collenchyma cells was drastically reduced. Determination of the nitric oxide (NO.) and gluthathione contents in leaves by confocal laser scanning microscopy and HPLC, respectively, showed a marked decrease of both compounds in plants treated with cadmium. The analysis of the S-nitrosoglutathione reductase (GSNOR) activity and its transcript expression in leaves showed a reduction of 31% by cadmium. These results indicate that GSNO is associated with a specific plant cell type, and this metabolite and its related catabolic activity, GSNOR, are both down-regulated under Cd stress.