Browsing by Author "Silva, B"
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- Challenges for scientific publishingPublication . Pestana, P; Ramalho, AR; Silva, B; Revés, J; Fernandes, M; Maurício, S
- Crosstalk between genetics, gene expression and biochemical markers supports systemic iron homeostasis dysregulation in alzheimer diseasePublication . Crespo, A; Silva, B; Ferreira, C; Marquesa, L; Marcelino, E; Maruta, C; Costa, S; Timóteo, A; Vilares, A; Couto, F; Faustino, P; Correia, AP; Verdelho, A; Porto, G; Guerreiro, M; Herrero Valverde, A; Costa, C; Mendonça, A; Costa, L; Martins, M
- Decrease in APP and CP mRNA expression supports impairment of iron export in Alzheimer's disease patientsPublication . Guerreiro, C; Silva, B; Crespo, A; Marques, L; Costa, S; Timóteo, A; Marcelino, E; Maruta, C; Vilares, A; Matos, M; Couto, F; Faustino, P; Verdelho, A; Guerreiro, M; Herrero Valverde, A; Costa, C; Mendonça, A; Martins, M; Costa, LAlzheimer'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<0.001) and amyloid-beta precursor protein (APP; P=0.006) genes in AD patients compared with healthy volunteers. These observations point out to a significant downregulation in the expression of genes associated with ferroportin-mediated cellular Fe export in PBMCs from AD patients, when compared to controls. Taken together, these findings support previous studies suggesting impairment of Fe homeostasis in AD, which may lead to cellular Fe retention and oxidative stress, a typical feature of this disease.
- Genetic and biochemical markers in patients with Alzheimer's disease support a concerted systemic iron homeostasis dysregulationPublication . Crespo, A; Silva, B; Marques, L; Marcelino, E; Maruta, C; Costa, S; Timóteo, A; Vilares, A; Couto, F; Faustino, P; Correia, AP; Verdelho, A; Porto, G; Guerreiro, M; Herrero Valverde, A; Costa, C; Mendonça, A; Costa, L; Martins, MAlzheimer'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.
- Impact of Routine Fractional Flow Reserve Evaluation During Coronary Angiography on Management Strategy and Clinical Outcome: One-Year Results of the POST-IT Multicenter RegistryPublication . Baptista, SB; Raposo, L; Santos, L; Ramos, R; Calé, R; Jorge, E; Machado, C; Costa, M; Oliveira, E; Costa, J; Pipa, J; Fonseca, N; Guardado, J; Silva, B; Sousa, MJ; Silva, JC; Rodrigues, A; Seca, L; Fernandes, RPenetration of fractional flow reserve (FFR) in clinical practice varies extensively, and the applicability of results from randomized trials is understudied. We describe the extent to which the information gained from routine FFR affects patient management strategy and clinical outcome. METHODS AND RESULTS: Nonselected patients undergoing coronary angiography, in which at least 1 lesion was interrogated by FFR, were prospectively enrolled in a multicenter registry. FFR-driven change in management strategy (medical therapy, revascularization, or additional stress imaging) was assessed per-lesion and per-patient, and the agreement between final and initial strategies was recorded. Cardiovascular death, myocardial infarction, or unplanned revascularization (MACE) at 1 year was recorded. A total of 1293 lesions were evaluated in 918 patients (mean FFR, 0.81±0.1). Management plan changed in 406 patients (44.2%) and 584 lesions (45.2%). One-year MACE was 6.9%; patients in whom all lesions were deferred had a lower MACE rate (5.3%) than those with at least 1 lesion revascularized (7.3%) or left untreated despite FFR≤0.80 (13.6%; log-rank P=0.014). At the lesion level, deferral of those with an FFR≤0.80 was associated with a 3.1-fold increase in the hazard of cardiovascular death/myocardial infarction/target lesion revascularization (P=0.012). Independent predictors of target lesion revascularization in the deferred lesions were proximal location of the lesion, B2/C type and FFR. CONCLUSIONS: Routine FFR assessment of coronary lesions safely changes management strategy in almost half of the cases. Also, it accurately identifies patients and lesions with a low likelihood of events, in which revascularization can be safely deferred, as opposed to those at high risk when ischemic lesions are left untreated, thus confirming results from randomized trials.