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Objectives: The objective of this study was to evaluate whether baseline 18F-fluorodeoxyglucose (FDG) uptake is associated with carotid plaque progression.Methods: A total of 156 subjects with carotid plaque were enrolled and underwent carotid magnetic resonance imaging (MRI) (at baseline and the 12-month follow-up) and positron emission tomography-computed tomography (PET-CT) (baseline). Carotid plaque progression was evaluated by two indices (the incidence of plaque progression and percentage of plaque increase) with three-dimensional (3D) imaging, while the 18F-FDG uptake was evaluated by the 18F-FDG uptake levels and 18F-FDG uptake velocity. The association between plaque progression and 18F-FDG uptake was investigated by the trend test and multivariate logistic regression analysis.Results: Of the 156 subjects, 80 (51.3%) showed carotid plaque progression during the 12-month follow-up. Firstly, no association was found between 18F-FDG uptake levels and plaque progression. Secondly, significant differences in the incidence of plaque progression were observed among the groups with different uptake velocities, showing a significant decreasing trend ranging from high to intermediate to low (p = 0.002, trend test). After adjusting for covariates, an adequate prediction of the 18F-FDG uptake velocity for the incidence of plaque progression was revealed (OR = 0.682, p < 0.05). In addition, no association was found between the 18F-FDG uptake velocity and the percentage of plaque increase in the subjects with plaque progression (p = 0.757, trend test).Conclusions: Our findings suggest 18F-FDG uptake velocity is independently associated with the incidence of carotid plaque progression. Additionally, the 18F-FDG uptake velocity, as another important parameter of PET-CT, warrants further study in future clinical research.Key Points: • The18F-FDG uptake levels were not associated with the carotid plaque progression. • The18F-FDG uptake velocity could predict the incidence of carotid plaque progression. • The18F-FDG uptake velocity with related factors warrants more attention in future clinical research. [ABSTRACT FROM AUTHOR]

The glucocorticoid receptor (GR) is the main effector of the activation of the hypothalamus-pituitary-adrenal (HPA) axis, which is caused by different types of stress that can be divided into two major categories: physical stress and psychological stress. Given the marked presence of GR in the hippocampus, GR-mediated hippocampal injury might be the core event under stress. The aim of this study was to investigate GR expression, hippocampal injury, and behaviors in rats to explore the differences between these types of stressors. Adult male rats were stressed using a classical model (electrical foot shock and a yoked psychologically stressful situation) to induce physical or psychological stress. The GR expression, injury of hippocampal subfields and behavioral abnormalities were dynamic, as demonstrated using immunofluorescence, 3D magnetic resonance imaging (MRI) and open field exploration (OFE), respectively. In addition, housing in a normal environment for 6 weeks was used to verify the recovery ability of rats. First, GR-mediated hippocampal atrophy and behavioral abnormalities were found in the second week under physical stress, but those changes did not appear until the fourth week under psychological stress. Second, the effects of stress were more pronounced after physical stressors than after psychological stressors in the fourth week, but this trend had reversed by the sixth week, especially in the DG (Dentate Gyrus) subfield. Except for the rats that had experienced 6 weeks of psychological stress, all rats showed significant recovery after 6 weeks of housing in a normal environment. The effects of physical stress appeared early but were relatively moderate, whereas the effects of psychological stress appeared late but were more severe. In addition, GR-mediated serious injury in the DG might be the cause of the DG volume loss and behaviors that could not be reversed. [ABSTRACT FROM AUTHOR]

The reduction of hippocampal volume remains controversial in depression because of the variability among individuals in clinical studies. Here, a reliable experimental rat model of depression, established by chronic unpredictable mild stress (CUMS), was used. Thirty rats were randomly divided into two groups (CUMS group and control group). Hippocampal volume was dynamically measured every 2 weeks in a 56-day chronic stress procedure using structural magnetic resonance imaging, and the correlation between the hippocampal volume and the learning and memory changes was investigated. Our results demonstrated that CUMS rats showed significantly smaller volumes of the bilateral hippocampus compared to that of the controls, changing dramatically with the development of CUMS procedure. The left hippocampal volume was reduced earlier and more markedly than the right one from the 2nd week to the 8th week of the CUMS procedure (on the 8th week: left: approximately 15.3 %; right: approximately 8.4 % reduction). Additionally, the hippocampal volume of CUMS rats was significantly negatively correlated with the learning and memory changes. Of note, it showed that the more obviously the hippocampal volume reduced, the more severely the learning and memory damaged. In conclusion, the hippocampal volume decreased gradually and dynamically and was correlated with the impairment of the learning and memory in depression. [ABSTRACT FROM AUTHOR]