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Alzheimer's disease (AD) is the most common form of dementia in the elderly individuals, resulting from a complex interaction between environmental and genetic factors. Impaired brain iron homeostasis has been recognized as an important mechanism underlying the pathogenesis of this disease. Nevertheless, the knowledge gathered so far at the systemic level is clearly insufficient. Herein, we used an integrative approach to study iron metabolism in the periphery, at both genotypic and phenotypic levels, in a sample of 116 patients with AD and 89 healthy control subjects. To assess the potential impact of iron metabolism on the risk of developing AD, genetic analyses were performed along with the evaluation of the iron status profile in peripheral blood by biochemical and gene expression studies. The results obtained showed a significant decrease of serum iron, ferritin, and transferrin concentrations in patients compared with the control subjects. Also, a significant decrease of ferroportin (SLC40A1) and both transferrin receptors TFRC and TFR2 transcripts was found in peripheral blood mononuclear cells from patients. At the genetic level, significant associations with AD were found for single nucleotide polymorphisms in TF, TFR2, ACO1, and SLC40A1 genes. Apolipoprotein E gene, a well-known risk factor for AD, was also found significantly associated with the disease in this study. Taken together, we hypothesize that the alterations on systemic iron status observed in patients could reflect an iron homeostasis dysregulation, particularly in cellular iron efflux. The intracellular iron accumulation would lead to a rise in oxidative damage, contributing to AD pathophysiology.

Microcystins (MC) are cyanotoxins occurring globally, known for causing acute hepatotoxicity in humans/animals, tumor promotion in animals and potential carcinogenicity. The mechanism of MC toxicity is considered a multi-pathway process involving the inhibition of protein phosphatases PP1/PP2A and the production of reactive oxygen species (ROS). However, their mechanism of action is not fully characterized, thus hampering the complete hazard identification. In this study, we evaluated the effect of several microcystin-LR concentrations on the growth, ROS levels, antioxidant system response and apoptosis induction on Saccharomyces cerevisiae. Our results showed that the growth of S. cerevisiae was not inhibited when compared to control cells. However, the staining of cells with DHR123 and DHE revealed an intracellular increase of the ROS levels. This ROS increase resulted in an augment of catalase activity and inhibition of SOD. All these facts suggest that hydrogen peroxide was the main ROS induced by MCLR. Signs of apoptosis were also detected in the cells exposed to toxin. Our results show that S. cerevisiae VL3 displays MCLR toxicity effects known to occur in higher eukaryotes and confirmed that it can be a simple and good model to help further in the elucidation of MCLR molecular mechanisms of toxicity. This research was partially supported by the European Regional Development Fund (ERDF) through the COMPETE – Operational Competitiveness Programme – and national funds through FCT – Foundation for Science and Technology – under the project PEst-C/MAR/LA0015/2013 and grant (SFRH/BPD/75922/2011) to E. Valério

This research was supported by the Fundação para a Ciência e a Tecnologia (FCT) [SFRH/BPD/29354/2006 to MM, SFRH/BD/60718/2009 to BS, and SFRH/BD/48671/2008 to LM]; Fundação Astrazeneca (Research Grant awarded through the “Programme of Support to Research”); Instituto Nacional de Saúde Dr. Ricardo Jorge; Portuguese Ministry of Health (Research Grant 53/2007 of the “Comissão de Fomento da Investigação em Cuidados de Saúde”); Lundbeck Portugal, Lda (Research Grant). Introduction: Alzheimer’s disease (AD) is the most common neurodegenerative disorder and the leading cause of dementia worldwide. Because of the clinical interest in its early diagnosis and prediction of patient evolution and prognosis, the identification of AD biomarkers is of crucial importance. Several lines of evidence implicate an imbalance of the redox-active biometals in AD. Metal-catalyzed hydroxyl radicals are potent mediators of cellular injury and are central to the oxidative injury hypothesis of AD pathogenesis [1,2]. Importantly, previous genetic and biochemical studies in AD patients support a concerted systemic iron metabolism dysregulation, namely at the level of cellular iron efflux [3]. Herein, we intended to further understand the molecular mechanisms underlying iron homeostasis in this pathology. In order to achieve this goal, the expression of specific iron metabolism-related genes directly involved in iron metabolism regulation and cellular iron export was measured in peripheral blood mononuclear cells from AD patients and healthy controls. Also, serum ceruloplasmin (CP) concentration and its oxidase activity were measured in all participants in the study, given the known role of this oxidase in facilitating iron exit from cells. Through this study we expect to further clarify the contribution of iron metabolism disruption to the etiopathogenesis of AD.

Alzheimer's disease (AD) is a neurodegenerative disorder of still unknown etiology and the leading cause of dementia worldwide. Besides its main neuropathological hallmarks, a dysfunctional homeostasis of transition metals has been reported to play a pivotal role in the pathogenesis of this disease. Dysregulation of iron (Fe) metabolism in AD has been suggested, particularly at the level of cellular iron efflux. Herein, we intended to further clarify the molecular mechanisms underlying Fe homeostasis in AD. In order to achieve this goal, the expression of specific Fe metabolism-related genes directly involved in Fe regulation and export was assessed in peripheral blood mononuclear cells (PBMCs) from 73AD patients and 74 controls by quantitative PCR. The results obtained showed a significant decrease in the expression of aconitase 1 (ACO1; P=0.007); ceruloplasmin (CP; P