Carolina Antunes Magalhães

Leptin in Alzheimer's disease.

Alzheimers disease (AD) is the most common cause of progressive dementia in the elderly population. AD is histologically characterized by accumulation of amyloid-β protein (Aβ) on extracellular plaques and deposition of hyperphosphorylated tau protein in intracellular neurofibrillary tangles. Several studies have shown that obesity may precede dementia and that lifestyle factors play a critical role in the onset of AD. Furthermore, accumulating evidence indicates that obesity is an independent risk factor for developing AD. In this scenario, the understanding of the role of adipose tissue in brain health is essential to clarify the establishment of demential processes. The objective of this work was to review studies regarding leptin, an anorexigenic peptide hormone synthesized in adipocytes, in the context of dementia. Some authors proposed that leptin evaluation might be a better predictor of dementia than traditional anthropometric measures. Leptin, once established as a biomarker, could enhance the understanding of late-onset AD risk over the life course, as well as the clinical progression of prodromal state to manifested AD. Other studies have proposed that leptin presents neuroprotective activities, which could be explained by inhibiting the amyloidogenic process, reducing the levels of tau protein phosphorylation and improving the cognitive function.

Increased tissue kallikrein amidase activity in urine of patients with type 1 diabetes under insulin therapy, and in those with gestational diabetes mellitus not under insulin therapy.

Human tissue kallikrein (hK1) is reduced in hypertension, cardiovascular and renal diseases. There is little information on the participation of hK1 in type 1 diabetes mellitus (DM), type 2 DM, and gestational diabetes mellitus (GDM), respectively. The aim of this study was to evaluate the roles of insulin and hyperglycemia on urinary hK1 activity in type 1 DM and in GDM. Forty-three type 1 DM patients (5-35 years, disease duration ≤ 5years, receiving insulin, HbA(1c)>7.6%) were selected. Forty-three healthy individuals, paired according to gender and age, were used as controls. Thirty GDM patients (18-42 years, between the 24th and 37th week of pregnancy, recently diagnosed, not under insulin therapy) were also selected. Thirty healthy pregnant (18-42years, between the 24th and 37th week of pregnancy) and 30 healthy non-pregnant women (18-42years) were selected as controls. Random midstream urine was used. hK1 amidase activity was estimated with D-Val-Leu-Arg-Nan substrate. Creatinine was determined by Jaffes method. hK1 specific amidase activity was expressed as μM/(minmg creatinine) to correct for differences in urine flow rate. hK1 specific amidase activity was significantly higher in the urine of type 1 DM than in controls, and in the urine of GDM patients than in healthy pregnant women and healthy non-pregnant women, respectively. The data suggest that hyperglycemia, rather than insulin, is involved in the mechanism of increased hK1 specific amidase activity in both type 1 DM and GDM patients, respectively.

EVALUATION OF PLATELET P-SELECTIN IN PATIENTS WITH ALZHEIMER'S DISEASE AND FRONTOTEMPORAL DEMENTIA

Background: Alcadeina (Alca) is a member of alcadein family composed of Alca, Alcb and Alcg, which is largely expressed in brain neuron and prone to form a tripartite complex with APP mediated by cytoplasmic neural-specific adaptor protein X11like (X11L). p3-Alca is generated from Alca by cleavage of aand g-secretases, and secreted into cerebrospinal fluid (CSF) and then into blood as does Ab from APP. The p3-Alca35 exists in CSF as a major species, as like as Ab40, while p3-Alca38 is minor as like as Ab42. p3-Alca is non-aggregatable so easily detected in CSF and plasma by sELISA (Hata 2009). To establish an effective AD diagnosis, we verified p3-Alca38/35, a ratio of p3-Alca38 to p3-Alca35. Methods: Previously, we showed the plasma level of p3-Alca35 using sELISAwith p3-Alca35 specific antibody (Omori 2014). To measure p3-Alca38/35 level, we tried to prepare new antibody raised to p3-Alca38 with higher affinity. Using cell surface display method, p3-Alca38 chimeric protein was expressed on cell surface and the cells were immunized. Several clones generating antibody specifically react to p3Alca38 were isolated, and we developed new sELISA system to quantify p3-Alca38 with higher sensitivity. Results:We first characterized the new sELISA systems to quantify p3-Alca38. With a combination of sELISA to quantify p3-Alca35, both p3-Alca35 and p3-Alca38 in body fluid were quantified. The levels p3Alca38/35 ratio in MCI and AD subjects showed a tendency increasing along with cognitive impairment degree compared to non-demented controls. The p3-Alca38/35 ratio significantly increased along with the increase of Ab42/40 ratio in vitro, while in vivo, the significant increase of p3-Alca38/35 correlated with the significant decrease of Ab42/40. Conclusions:Our study suggested that p3-Alca38/35 can be an effective biomarker of AD not only in CSF but also in plasma, which indicates a qualitative change of g-secretase activity. Further studies with samples from various cohorts (for example, with chronologically chasing and taking samples) will be performed to confirm the efficiency of p3-Alca38/35 as a biomarker to find prodromal and/or early stage MCI/AD subjects who shows an altered/attenuated g-secretase activity.

Blood neuron cell-derived microparticles as potential biomarkers in Alzheimer’s disease

Carolina A. Magalhães, Fernanda M. Campos, Cristina M.G. Loures, Vanessa G. Fraga, Ana Carolina R. Oliveira, Amanda C. Chaves, Natália P. Rocha, Leonardo C. de Souza, Raphael D. Maia, Henrique C. Guimarães, Marco Túlio G. Cintra, Elvis C.C. Mateo, Maria Aparecida C. Bicalho, Maria das Graças Carvalho, Lirlândia P. Sousa, Paulo Caramelli and Karina B. Gomes* Blood neuron cell-derived microparticles as potential biomarkers in Alzheimer’s disease

MICROPARTICLES DERIVED FROM TISSUE FACTOR, LEUKOCYTE, ENDOTHELIUM AND NEURON ARE ASSOCIATED WITH ALZHEIMER’S DISEASE

panel of rat (APPsi) and mouse (Tg4-42) biofluids and tissues. This give further help to understand the devastating neurodegenerative disease, related complex biochemical pathways and pathophysiological processes of AD.Conclusions:UsingNMR-basedmetabolic phenotyping we defined a quantitative readout of transgenic animal models in the form of a biomarker panel. These biomarkers not only contribute to the understanding of this devastating neurodegenerative disease and the related pathophysiological processes on a systemic level, but set the base for a wide range of biomedical applications. Our approach can be easily extended to other tissues, matrices, or disease models and translated across species since metabolic pathways are conserved through evolution, and are essentially similar in rodents and humans.

Cerebrospinal fluid biomarkers for the differential diagnosis of Alzheimer’s disease

Introduction: Several studies have been conducted in order to validate cerebrospinal fluid biomarkers for the diagnosis of Alzheimer’s disease (AD), aiming primarily to facilitate the early diagnosis. Objective: To evaluate CSF biomarkers on patients with probable AD and the applicability of the international references values in this population. Methods: 46 individuals were recruited and classified as probable AD (n = 19), mild cognitive impairment (MCI) (n = 5) and other dementias (n = 22). The cerebrospinal fluid (CSF) biomarkers were measured using the INNOTEST kits for enzyme-linked immunosorbent assay (ELISA). Higher Tau protein values and lower Aβand Innotest Amyloid Tau Index (IATI) values were observed in AD group when compared with MCI; higher levels of Tau and phosphorylated Tau (P-Tau), and lower Aβand IATI values were observed in AD group when compared to patients with other dementias. No biomarker or IATI was able to distinguish between MCI and other dementias. The kappa index between biomarkers and the clinical diagnosis was regular to Tau and IATI, and weak to Aβand P-tau. Conclusion: The cut-off values for each biomarker that showed better combined sensibility and specificity differ from the reference values suggested by the manufacturer. The CSF biomarkers represent important resources that can help with the AD diagnosis, although the results interpretation must be made based on the analysis of the three analytes together. The cut-off values must be established to address the specificities and characteristics of each population.

Human Tissue Kallikrein Activity in Angiographically Documented Chronic Stable Coronary Artery Disease

Background Human tissue kallikrein (hK1) is a key enzyme in the kallikrein–kinin system (KKS). hK1-specific amidase activity is reduced in urine samples from hypertensive and heart failure (HF) patients. The pathophysiologic role of hK1 in coronary artery disease (CAD) remains unclear. Objective To evaluate hK1-specific amidase activity in the urine of CAD patients Methods Sixty-five individuals (18–75 years) who underwent cardiac catheterism (CATH) were included. Random midstream urine samples were collected immediately before CATH. Patients were classified in two groups according to the presence of coronary lesions: CAD (43 patients) and non-CAD (22 patients). hK1 amidase activity was estimated using the chromogenic substrate D-Val-Leu-Arg-Nan. Creatinine was determined using Jaffé’s method. Urinary hK1-specific amidase activity was expressed as µM/(min · mg creatinine) to correct for differences in urine flow rates. Results Urinary hK1-specific amidase activity levels were similar between CAD [0.146 µM/(min ·mg creatinine)] and non-CAD [0.189 µM/(min . mg creatinine)] patients (p = 0.803) and remained similar to values previously reported for hypertensive patients [0.210 µM/(min . mg creatinine)] and HF patients [0.104 µM/(min . mg creatinine)]. CAD severity and hypertension were not observed to significantly affect urinary hK1-specific amidase activity. Conclusion CAD patients had low levels of urinary hK1-specific amidase activity, suggesting that renal KKS activity may be reduced in patients with this disease.