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Alana Costa

    Alana Costa

    Cholesterol is an essential component in the structure and function of cell membranes and has been associated with the major pathological signatures of Alzheimer's disease (AD). To maintain brain cholesterol homeostasis, it is... more
    Cholesterol is an essential component in the structure and function of cell membranes and has been associated with the major pathological signatures of Alzheimer's disease (AD). To maintain brain cholesterol homeostasis, it is converted into 24(S)‐hydroxycholesterol (24OHC) which can be driven through the blood‐brain barrier. Several studies have already described a decrease in 24OHC and an increase of 27(S)‐hydroxycholesterol (27OHC) in AD, as a reflection of disease burden, the loss of metabolically active neurons and the degree of structural atrophy. It is also well known that peripheral cholesterol is altered in AD patients. However, there are no data regarding effects of AD treatment in this cholesterol pathway. Since a study from our group indicated a significant increase in membrane phospholipid metabolism by donepezil, the aim of this study was to evaluate the effect of short‐ and long‐term donepezil treatment on cholesterol and metabolites 24OHC and 27OHC in plasma of A...
    Phospholipase A 2 is the main enzyme in the metabolism of membrane phospholipids. It comprises a family of enzymes divided into iPLA 2 , cPLA 2 and sPLA 2 . Studies have reported increased PLA 2 activity in psychotic patients, which... more
    Phospholipase A 2 is the main enzyme in the metabolism of membrane phospholipids. It comprises a family of enzymes divided into iPLA 2 , cPLA 2 and sPLA 2 . Studies have reported increased PLA 2 activity in psychotic patients, which suggests an accelerated breakdown of membrane phospholipids. In the present study we investigated whether increased PLA 2 activity is also present in individuals at ultra-high risk (UHR) for psychosis. One-hundred fifty adults were included in this study (85 UHR and 65 controls). UHR was assessed using the “structured interview for prodromal syndromes”. PLA 2 activity was determined in platelets by a radio-enzymatic assay. We found in UHR individuals increased activities of iPLA 2 ( p  < 0.001) and cPLA 2 ( p  = 0.012) as compared to controls. No correlations were found between socio-demographic and clinical parameters and PLA 2 activity. Our findings suggest that increased PLA 2 activities may be useful as a biological risk-marker for psychotic disorders.
    The onset of frank psychosis is usually preceded by a prodromal phase characterized by attenuated psychotic symptoms. Currently, research on schizophrenia prodromal phase (ultra‐high risk for psychosis [UHR]) has focused on the risk of... more
    The onset of frank psychosis is usually preceded by a prodromal phase characterized by attenuated psychotic symptoms. Currently, research on schizophrenia prodromal phase (ultra‐high risk for psychosis [UHR]) has focused on the risk of developing psychosis, on the transition to full blown psychosis and on its prediction. Neurobiological differences between UHR individuals who fully recover (remitters) versus those who show persistent/progressive prodromal symptoms (nonremitters) have been little explored. The endocannabinoid system constitutes a neuromodulatory system that plays a major role in brain development, synaptic plasticity, emotional behaviours and cognition. It comprises two cannabinoid receptors (CB1/CB2), two endocannabinoid ligands, arachidonylethanolamide (AEA) and 2‐arachidonoylglycerol (2AG) along with their inactivation enzymes. Despite much evidence that the endocannabinoid system is imbalanced during psychosis, very little is known about it in UHR. Therefore, we aimed to quantify the plasma endocannabinoid levels in UHR and healthy controls (HC) and verify if these metabolites could differentiate between remitters and nonremitters. Circulating concentrations of AEA (p = .003) and 2AG (p < .001) were lower in UHR when compared with HC, with no difference between remitters and nonremitters. Regarding clinical evolution, it was observed that out of 91 UHRs initially considered, 16 had psychiatric complaints (3 years of follow‐up). Considering those subjects, there were weak correlations between clinical parameters and plasma concentrations of endocannabinoids. Our results suggest that the endocannabinoids are imbalanced before frank psychosis and that changes can be seen in plasma of UHR individuals. These molecules proved to be potential biomarkers to identify individuals in the prodromal phase of psychosis.
    BACKGROUND The identification of Ultra-High Risk (UHR) individuals is thought to be useful for early intervention to improve psychosis outcomes. However, transition rates vary widely, and there is an effort to make these criteria more... more
    BACKGROUND The identification of Ultra-High Risk (UHR) individuals is thought to be useful for early intervention to improve psychosis outcomes. However, transition rates vary widely, and there is an effort to make these criteria more specific and accurate. Neuroinflammation has been discussed in the pathophysiology of psychosis. The metabolism of eicosanoids is a key process in inflammatory states. Therefore, we investigated whether the study of the inflammatory COX-2 pathway through the quantification of the eicosanoid levels can be a useful approach for the characterisation of UHR individuals. METHODS One hundred and twenty-two individuals were included in this study (67 UHR and 55 controls) based on performance on the Prodromal Questionnaire. UHR status was assessed by Structured Interview for Prodromal Syndromes (SIPS). We determined the levels of Prostaglandin F2α (PGF2α), Prostaglandin E2 (PGE2), and Thromboxane B2 (TxB2) in plasma using ELISA assays. RESULTS Concentrations of PGE2 and TxB2 were increased in UHR compared to controls (p = 0.01 and p < 0.05, respectively). PGE2 and PGF2α levels were correlated to negative symptoms (p < 0.01 and p < 0.05), whereas TxB2 correlated with positive symptoms (p = 0.05) as assessed by the SIPS. CONCLUSIONS Our findings suggest that overactivation of the COX-2 pathway may be related to an increased risk for psychosis. However, our data do not allow us to draw conclusions related to the cause-effect mechanisms. Future studies should determine whether the levels of the eicosanoids have a predictive value for the transition of UHR to frank psychosis.
    The cellular and molecular mechanisms underlying onset and development of schizophrenia have not yet been completely elucidated, but the association of disturbed neuroplasticity and inflammation has gained particular relevance recently.... more
    The cellular and molecular mechanisms underlying onset and development of schizophrenia have not yet been completely elucidated, but the association of disturbed neuroplasticity and inflammation has gained particular relevance recently. These mechanisms are linked to annexins functions. ANXA3, particularly, is associated to inflammation and membrane metabolism cascades. The aim was to determine the ANXA3 levels in first-onset drug-naïve psychotic patients. We investigated by western blot the protein expression of annexin A3 in platelets of first-onset, drug-naïve psychotic patients (diagnoses according to DSM-IV: 28 schizophrenia, 27 bipolar disorder) as compared to 30 age- and gender-matched healthy controls. Annexin A3 level was lower in schizophrenia patients as compared to healthy controls ( p  < 0.001) and to bipolar patients ( p  < 0.001). Twenty out of 28 schizophrenic patients had undetectable annexin A3 levels, as compared to none from the bipolar and none from the control subjects. ANXA3 was reduced in drug-naïve patients with schizophrenia. ANXA3 affects neuroplasticity, inflammation and apoptosis, as well as it modulates membrane phospholipid metabolism. All these processes have been discussed in regard to the biology of schizophrenia. In face of these data, we feel that further studies with larger samples are warranted to investigate the possible role of reduced ANXA3 as a possible risk marker for schizophrenia.
    Abstract Objectives: Expression of phospholipids and related molecules could provide panels of multiple biomarkers searching for the signature of Alzheimer’s disease (AD). The aim of the present study was to quantify ten phospholipids and... more
    Abstract Objectives: Expression of phospholipids and related molecules could provide panels of multiple biomarkers searching for the signature of Alzheimer’s disease (AD). The aim of the present study was to quantify ten phospholipids and simultaneously determine phospholipase A2 (PLA2) activity in blood of mild cognitive impairment (MCI) and AD patients. Methods: Thirty-four AD, 20 MCI and 25 controls were enrolled. The phospholipids where analysed using the AbsoluteIDQ® p180 Kit. PLA2 activities were accessed in platelets by a radio-enzymatic assay. Results: The study failed to fix the ten phospholipids as a panel to predict AD; the levels of PCaaC36:6, PCaaC40:6 and C16:1-OH were lower in MCI than in controls (P = 0.041, P = 0.012, P = 0.044 respectively). PCaaC40:2 levels were lower in MCI than in AD (P = 0.041). The converters MCI-AD showed at baseline lower levels of PCaaC40:2 (P = 0.050) and PCaaC40:6 (P = 0.037) than controls. iPLA2 activity was reduced in AD and MCI than in controls (P < 0.001). We found positive correlation in the control group between PCaaC38:6 and tPLA2 (r = 0.680; P = 0.001) and sPLA2 (r = 0.601; P = 0.004); PCaaC40:1 and iPLA2 (r = 0.503; P = 0.020); PCaaC40:6 and tPLA2 (r = 0.532; P = 0.013) and sPLA2 (r = 0.523; P = 0.015). Conclusions: Lipids metabolites in plasma might indirectly indicate changes in neuronal membrane and this deregulation can outline the transition between healthy and diseased brains.