The European Centre for the Validation of Alternative Methods (ECVAM) proposes to make the validation process more flexible, while maintaining its high standards. The various aspects of validation are broken down into independent modules, and the information necessary to complete each module is defined. The data required to assess test validity in an independent peer review, not the process, are thus emphasised. Once the information to satisfy all the modules is complete, the test can enter the peer-review process. In this way, the between-laboratory variability and predictive capacity of a test can be assessed independently. Thinking in terms of validity principles will broaden the applicability of the validation process to a variety of tests and procedures, including the generation of new tests, new technologies (for example, genomics, proteomics), computer-based models (for example, quantitative structure–activity relationship models), and expert systems. This proposal also aims to take into account existing information, defining this as retrospective validation, in contrast to a prospective validation study, which has been the predominant approach to date. This will permit the assessment of test validity by completing the missing information via the relevant validation procedure: prospective validation, retrospective validation, catch-up validation, or a combination of these procedures.

We previously described the behaviour of different cobalt forms, i.e., cobalt nanoparticles (CoNP), cobalt microparticles (CoMP) and cobalt ions (Co(2+)), in culture medium (dissolution, interaction with medium components, bioavailability) as well as their uptake and intracellular distribution in Balb/3T3 mouse fibroblasts (Sabbioni, Nanotoxicology, 2012). Here, we assess the cytotoxicity and morphological transformation of CoNP compared not only to Co(2+), but also to CoMP and to released Co products. Cytotoxicity reached maximum at 4-h exposure, with ranking CoMP > CoNP > Co(2+). However, if we consider toxicity as a function of intracellular Co, toxicity of the ionic forms seems to prevail over the particles. Co forms other than Co(2+) released from particles had toxicity intermediate between particles and ions. Alterations in concentrations of essential elements (Cu, Mg, Zn) in cells exposed to Co particles may contribute to toxicity. Both CoMP and CoNP (but not Co(2+) and other released Co forms) induced morphological transformation (CoMP > CoNP). This was dependent on reactive oxygen species production and lipid peroxidation, as indicated by inhibition of type III foci with ascorbic acid. The present results suggest that the previously demonstrated massive mitochondrial and nuclear Co internalisation and DNA adduct formation by CoMP and CoNP (Sabbioni, Nanotoxicology, 2012) induce toxicity and transformation. On the contrary, the role of ions released by particles in culture medium is negligible. Thus, both the chemical and the physical properties of Co particles contribute to cytotoxicity and morphological transformation.

AimsPatients with intestinal malabsorption may develop cardiac dysfunction the origin of which is often unclear. We sought to investigate the pathogenesis of dilated cardiomyopathy in human malabsorption. Methods and resultsEighteen patients with intestinal bypass as treatment for severe obesity and cardiomyopathy underwent endomyocardial biopsy. Biopsies were processed by histology, electron microscopy, polymerase chain reaction (PCR) for cardiotropic viruses, instrumental neutron activation analysis (INAA) of 33 myocardial trace elements, and assessment of glutathione peroxidase (GPX) activity and LC3-II expression. Histology and electron microscopy showed hypertrophy/degeneration of cardiomyocytes with pronounced cell autophagy and high expression of LC3-II. PCR was negative for viral genomes. INAA showed severe myocardial selenium (Se) and zinc (Zn) deficiency and reduced GPX activity vs. both patients with idiopathic dilated cardiomyopathy and normal controls. Se and Zn were added to antifailing heart therapy in 10 patients (group A1) agreeing to a control biopsy, and the response was compared with that of 8 patients (group A2) on supportive therapy alone. After 6 months, myocardial normalization of Se, Zn, LC3-II, and GPX in group A1 was associated with recovery of cardiomyocyte degeneration and autophagy, and significant improvement in cardiac dimension and function, that remained unchanged in group A2. ConclusionA reversible Se-and Zn-deficient cardiomyopathy may occur in patients with intestinal malabsorption. It is characterized by decline of myocardial antioxidant reserve, oxidative damage of cell membranes, and enhanced cell autophagy.--

The mechanistic understanding of nanotoxicity requires the physico-chemical characterisation of nanoparticles (NP), and their comparative investigation relative to the corresponding ions and microparticles (MP). Following this approach, the authors studied the dissolution, interaction with medium components, bioavailability in culture medium, uptake and intracellular distribution of radiolabelled Co forms (CoNP, CoMP and Co(2+)) in Balb/3T3 mouse fibroblasts. Co(2+) first saturates the binding sites of molecules in the extracellular milieu (e.g., albumin and histidine) and on the cell surface. Only after saturation, Co(2+) is actively uptaken. CoNP, instead, are predicted to be internalised by endocytosis. Dissolution of Co particles allows the formation of Co compounds (CoNP-rel), whose mechanism of cellular internalisation is unknown. Co uptake (ranking CoMP > CoNP > Co(2+)) reached maximum at 4 h. Once inside the cell, CoNP spread into the cytosol and organelles. Consequently, massive amounts of Co ions and CoNP-rel can reach subcellular compartments normally unexposed to Co(2+). This could explain the fact that the nuclear and mitochondrial Co concentrations resulted significantly higher than those obtained with Co(2+).

No abstract