Camila de Godoi Carneiro

Aging Effects on Whole-Brain Functional Connectivity in Adults Free of Cognitive and Psychiatric Disorders

Aging is associated with decreased resting-state functional connectivity (RSFC) within the default mode network (DMN), but most functional imaging studies have restricted the analysis to specific brain regions or networks, a strategy not appropriate to describe system-wide changes. Moreover, few investigations have employed operational psychiatric interviewing procedures to select participants; this is an important limitation since mental disorders are prevalent and underdiagnosed and can be associated with RSFC abnormalities. In this study, resting-state fMRI was acquired from 59 adults free of cognitive and psychiatric disorders according to standardized criteria and based on extensive neuropsychological and clinical assessments. We tested for associations between age and whole-brain RSFC using Partial Least Squares, a multivariate technique. We found that normal aging is not only characterized by decreased RSFC within the DMN but also by ubiquitous increases in internetwork positive correlations and focal internetwork losses of anticorrelations (involving mainly connections between the DMN and the attentional networks). Our results reinforce the notion that the aging brain undergoes a dedifferentiation processes with loss of functional diversity. These findings advance the characterization of healthy aging effects on RSFC and highlight the importance of adopting a broad, system-wide perspective to analyze brain connectivity.

The contributions of dipeptidyl peptidase IV to inflammation in heart failure

Circulating dipeptidyl peptidase IV (DPPIV) activity correlates with cardiac dysfunction in humans and experimental heart failure (HF) models. Similarly, inflammatory markers are associated with poorer outcomes in HF patients. However, the contributions of DPPIV to inflammation in HF remain elusive. Therefore, this study aimed to investigate whether the cardioprotective effects of DPPIV inhibition after myocardial injury are accompanied by reduced cardiac inflammation, whether circulating DPPIV activity correlates with the levels of systemic inflammatory markers in HF patients, and whether leukocytes and/or splenocytes may be one of the sources of circulating DPPIV in HF. Experimental HF was induced in male Wistar rats by left ventricular myocardial injury after radiofrequency catheter ablation. The rats were divided into three groups: sham, HF, and HF + DPPIV inhibitor (sitagliptin). Six weeks after surgery, cardiac function, perfusion and inflammatory status were evaluated. Sitagliptin treatment improved cardiac function and perfusion, reduced macrophage infiltration, and diminished the levels of inflammatory biomarkers including TNF-α, IL-1β, and CCL2. In HF patients, serum DPPIV activity correlated with CCL2, suggesting that leukocytes may be the source of circulating DPPIV in HF. Unexpectedly, DPPIV release was higher in splenocytes from HF rats and similar in HF circulating mononuclear cells compared with those from sham, suggesting an organ-specific modulation of DPPIV in HF. Collectively, our data provide new evidence that the cardioprotective effects of DPPIV inhibition in HF may be due to suppression of inflammatory cytokines. Moreover, they suggest that a vicious circle between DPPIV and inflammation may contribute to HF development and progression.

Gray matter volumes in patients with bipolar disorder and their first-degree relatives

Bipolar disorder (BD) is highly heritable. First-degree relatives of BD patient have an increased risk to develop the disease. We investigated abnormalities in gray matter (GM) volumes in healthy first-degree relatives of BD patients to identify possible brain structural endophenotypes for the disorder. 3D T1-weighted magnetic resonance images were obtained from 25 DSM-IV BD type I patients, 23 unaffected relatives, and 27 healthy controls (HC). A voxel-based morphometry protocol was used to compare differences in GM volumes between groups. BD patients presented reduced GM volumes bilaterally in the thalamus compared with HC. Relatives presented no global or regional GM differences compared with HC. Our negative results do not support the role of GM volume abnormalities as endophenotypes for BD. Thalamic volume abnormalities may be associated the pathophysiology of the disease.

18F-Fluoride PET/CT and 99mTc-MDP SPECT/CT can detect bone cancer at early stage in rodents

&NA; Noninvasive imaging using positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/computed tomography (SPECT/CT) are considered revolutionized approaches to detect bone cancer. Both PET/CT and SPECT/CT technologies have advanced to permit miniaturization, which has provided the advantage of including animals as their own controls in longitudinal studies. The present study was designed to evaluate the potential of PET/CT and SPECT/CT as research tools to detect bone cancer in rats. We used a rat model of bone cancer induced by injecting Walker 256 tumor cells into the femoral cavity. Computed tomography demonstrated that rats presented a solid tumor at 15 days post injection (dpi). However, CT was not an effective method for identifying tumors at an earlier time point (8 dpi), when mechanical hyperalgesia (the most common symptom during bone cancer progression) had already initiated. At this early stage, PET/CT and SPECT/CT analysis detected higher uptake in the injected femur of the tracers 18F‐Fluoride and 99mTc‐Methyl diphosphonate (99mTc‐MDP), respectively. These findings demonstrated for the first time that both 18F‐Fluoride PET/CT and 99mTc‐MDP SPECT/CT can detect cancer at early stages in rats and advocates for the PET/SPECT/CT as research tools to evaluate bone cancer in further longitudinal studies involving small animals.

[18F]FDG PET imaging evaluation on non-alcoholic fatty liver disease and hepatocellular carcinoma model treated with sorafenib

Aim: Evaluate the effect of sorafenib in a rat model of non-alcoholic fatty liver disease (NAFLD) related to hepatocellular carcinoma (HCC) by quantifying the correlation between changes in glucose metabolism on PET imaging and degree of tumor differentiation. Methods: NAFLD related HCC was induced by the combination of high fat and choline deficient diet with diethylnitrosamine (100 mg/L) for 16 weeks. Then carcinogenic stimuli were suspended, liver nodules were identified by abdominal ultrasound and two groups were randomized: control (n = 10) and sorafenib (n = 20). Rats received daily gavage administration of 1 mL saline or sorafenib (5 mg/kg/day) for more 3 weeks. After treatment, [F]FDG PET scan was performed on animals. Results: [F]FDG uptake was lower in the sorafenib group than that in the control group (3.3 ± 0.48 vs . 5.5 ± 1.5, P = 0.01). Direct correlation was found between poorly-differentiated HCC and TumorSUVmax/MuscleSUVmax ratio (R = 0.54, P = 0.006). Treatment was associated with significantly more residual tumors that were well differentiated (Grades I/II) than in the untreated control group (39% vs . 5%, respectively, P = 0.01). Conclusion: Sorafenib shows promise as a treatment for reducing the aggressiveness of HCC as demonstrated by [F] FDG PET and immunohistochemistry.

7-Ketocholesterol loaded-phosphatidylserine liposome induces cell death, autophagy, and growth inhibition of melanoma and breast adenocarcinoma.

Background: The exposure of phosphatidylserine (PS) is one of the first steps of programmed cell death. Phagocytosis on cancer microenvironment is well described in tumors and is associated with malignancy and poor prognosis. Tumor associated macrophages (TAMs) act suppressing the anticancer immune response. The tumor parenchymal cells are also capable of phagocytosis cells in apoptosis. In a previous study we observed that 7-ketocholesterol is capable of inducing autophagy on melanoma cell. Aims: Evaluate the activities of a 7-ketocholesterol loaded-phosphatidylserine liposome on autophagy and phagocytosis of tumor microenvironment. Methods: Liposomes were constituted by 20 mg commercial Phosphatidylserine (PS) and PS associated with 5 mg of 7-ketocholesterol extracted with chloroform/methanol (10: 1), dried, resuspended in 10 mL phosphate buffer, homogenized and sonicated for 6 minutes. The size and Zeta Pontencial (ZP) of liposomes were evaluated. Antiinflammatory activity of liposomes was evaluated by paw edema induced by carrageenan. A dependent-dose effect of liposomes on J774 macrophages, B16F10 melanoma cells, and 4T1 breast cancer cells was assessed by MTT. Cell death evaluations, for the same cells, were performed by flow cytometry with propidium iodide (PI) staining. The presence of acid vacuoles related to autophagy was evaluated by flow cytomery by acridine orange staining. The effects of the liposomes in vivo were evaluated by B16F10 melanoma-bearing C57/bl6 mice and 4T1 breast cancer-bearing Balb c mice. Endocytosis efficiency of the liposomes was observed by labeling it with PKH26 fluorescent staining and evaluated in 4T1 cells after 12 h. Liposomes were radiolabeled by adding 1 to 30 mCi of 99mTc radiopharmaceuticals (99mTcO4-, 99mTc-dextran-70, 99mTc-MIBI, 99mTc-DISIDA) and 18FDG; the solution was homogenized and sonicated for 6 minutes. The samples were centrifuged and part of the supernatant was added to an Amicon® filter (10kD) and concentrated, the concentrated was diluted with 400 uL of PBS and concentrated again. Liposome incorporation was determined by quotient of the radioactivity in the Amicon® by sum of Amicon® and filtrated solutions. Furthermore, lipophilicity (L), hydrophilicity (H), and charge (-/0/+) of the radioactive material were considered in the final analysis. Results: PS liposomes presented 141,9nm + 9,101 size with a -25,2 ZP; PS-7-ketocholesterol (PS/7KC) liposomes presented 153,9 nm + 10,35 size with a -29,1 ZP. The paw edema was inhibited by both liposomes after 240 min of the carrageenan induction. The concentration of 26 uM/mL of PS and PS/7KC liposomes stimulated cell proliferation. PS/7KC at the concentrations above 84 uM/mL inhibited the cell proliferation. PS/7KC showed intense antiproliferative activity in melanoma cells and breast adenocarcinoma cells, assessed by the MTT method and by flow cytometry with PI. It was observed 10% more autophagic vacuoles on melanoma cells treated with PS/7KC than the control groups. Both in vivo tumor models had the same antiproliferative effect of the PS/7KC liposomes with daily doses. Daily doses of PS liposomes induced a high size of tumors. 99mTc-MIBI was efficiently and strongly incorporated to liposomes than the other proposed formulations. Conclusion: PS liposomes have effects in vivo and in vitro and must be related to phagocyte and autophagy activities. PS/7KC impairs J774 macrophage, B16F10 melanoma, and 4T1 breast adenocarcinoma cell growth. PS/7KC induces the presence of acid vacuoles corresponding to autophagy. The liposomes had a high endocytosis evaluated by PKH 26 labelled particles. PS keeps the tumor proliferation and PS/7KC inhibits tumor growth after ten days of daily doses. Supported by CNPq and Fundacao Araucaria. Citation Format: Giovani Marino Favero, Tharcisio Citrangulo Tortelli, Jr., Daniel Fernandes, Ana Paula Prestes, Louise N.B. Kmetiuk, Andreia Hanada Otake, Luciana N.S. Andrade, Daniele de Paula Faria, Camila de Godoi Carneiro, Alexandre Teles Garcez, Fabio L.N. Marques, Roger Chammas. 7-Ketocholesterol loaded-phosphatidylserine liposome induces cell death, autophagy, and growth inhibition of melanoma and breast adenocarcinoma [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; Sao Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr A50.

EPA-0082 - Age-related changes in the posterior cingulate cortex functional connectivity: a resting-state fmri study in adults free of neuropsychiatric disorders

Introduction Studies of normal aging have shown age-related decreases in functional connectivity (FC) within the default mode network (DMN), particularly involving the posterior cingulate cortex (PCC). Although psychiatric conditions are common and underdiagnosed, none of these studies have combined psychiatric structured interview and neuropsychological evaluation to select the sample. Objectives to characterize age-related changes in PCC-FC connectivity in adults carefully screened to rule out neuropsychiatric disorders. Methods neuropsychiatric disorders were excluded by the Structured Clinical Interview for DSM-IV and neuropsychological evaluation. Restingstate functional MRI was acquired from 40, young, middle-age and elderly participants. After preprocessing, whole-brain, seed-based FC was estimated using a PCC seed. The relationship between age and PCC-FC was assessed using partial least squares. Results age was positively associated with PCC-FC in the left dorsolateral prefrontal cortex, bilateral supplementary motor area, right insula and left cerebellum; PCC-FC in these regions was negative or close to zero in young adults. PCC-FC of the medial part of the ventral prefrontal cortex was negatively associated with age; this region presented high positive PCC-FC in young adults (see figure). Conclusions age-related increases in PCC-FC were found in regions which are anti-correlated with the DMN, suggesting a decrease in the magnitude of anti-correlation. This may reflect a dedifferentiation process or weaker inter-network interactions. The careful sample selection prevents confounds related to neuropsychiatric disorders. Download : Download full-size image

AGE-RELATED FUNCTIONAL CONNECTIVITY CHANGES: VARIATIONS IN MAGNITUDE AND SHIFTS FROM NEGATIVE TO POSITIVE CORRELATIONS

matter. Models were adjusted for age, sex, scan interval, intracranial volume, white matter atrophy and white matter lesion load. Additionally, influence of cardiovascular risk factors on DTI changes was studied. Results: Over 2 years of follow-up, global FA decreased by 0.0038 (p<10 -6), while MD increased by 9.0 x 10 -6 mm 2/s (p<10 -6) reflecting loss of white matter microstructure. Voxelwise analyses showed that FA decreased widespread in the brain, except in the sensorimotor pathway, where an increase in FA was found (see Figure). MD values increased throughout the white matter. In addition to the change over time, we found more pronounced white matter diffusion changes in older persons. Cardiovascular risk factors were not associated with changes in tissue microstructure. Conclusions: In a large population of non-demented elderly, we found longitudinal changes in FA and MD, reflecting loss of white matter microstructure over time. Our results are suggestive of widespread normal appearing white matter changes in aging, with relative sparing of sensorimotor fibres. Furthermore, we found that white matter degeneration is more pronounced with higher age, but not driven by specific cardiovascular risk factors.