[Association between brain glucose metabolism and cardiac dysfunction in patients with ischemic heart disease undergoing (18)F-FDG PET/CT imaging]

Objective: To evaluate the relationship between the brain glucose metabolism and left ventricular function parameters, and to explore the cerebral glucose metabolism reduction regions in patients with ischemic heart disease (IHD). Methods: A total of 110 consecutive IHD patients who underwent gated (99)Tc(m)-sestamibi (MIBI) SPECT/CT myocardial perfusion imaging, gated (18)F-fluorodeoxyglucose (FDG) PET/CT myocardial and brain glucose metabolic imaging within three days in Beijing Anzhen Hospital from April 2016 to October 2017, were enrolled in this study. Left ventricular functional parameters of SPECT/CT and PET/CT including end-diastolic volume (EDV), end-systolic volume (ESV) and left ventricular ejection fraction (LVEF) were analyzed by QGS software. Viable myocardium and myocardial infarction region were determined by 17-segment and 5 score system, and the ratio of viable myocardium and scar myocardium was calculated. According to the range of viable myocardium, the patients were divided into viable myocardium<10% group (n=44), viable myocardium 10%-<20% group (n=36) and viable myocardium≥20% group (n=30). Pearson correlation analysis was used to analyze the correlation between the range of viable myocardium and scar myocardium and the level of cerebral glucose metabolism. Brain glucose metabolism determined by the mean of standardized uptake value (SUV(mean)) was analyzed by SPM. The ratio of SUV(mean) in whole brain and SUV(mean) in cerebellum were calculated, namely taget/background ratio (TBR). Differences in cerebral glucose metabolism among various groups were analyzed by SPM. Results: There were 101 males, and age was (57±10) years in this cohort. The extent of viable myocardium and the extent of scar, LVEF evaluated by SPECT/CT and PET/CT were significantly correlated with TBR (r=0.280, r=-0.329, r=0.188, r=0.215 respectively,all P<0.05). TBR value was significantly lower in viable myocardium<10% group, compared with viable myocardium 10%-<20% group (1.25±0.97 vs. 1.32±0.17, P<0.05) and viable myocardium≥20% group (1.25±0.97 vs. 1.34±0.16, P<0.05). Furthermore, in comparison with viable myocardium≥20% group, the hypo-metabolic regions of viable myocardium<10% group were located in the precuneus, frontal lobe, postcentral gyrus, parietal lobe, temporal lobe, and so on. Conclusions: There is a correlation between impaired left ventricular function and brain glucose metabolism in IHD patients. In IHD patients with low myocardial viability, the level of glucose metabolism in the whole brain is decreased, especially in the brain functional areas related to cognitive function.

[Differences of brain functional alterations between subtypes of Cushing's syndrome patients]

Objective: To compare the differences of brain functional damage of subtypes of patients with Cushing's syndrome (CS). Methods: A total of 11 adrenocorticotropic hormone (ACTH)-dependent CS patients and 29 ACTH-independent CS patients were recruited from Chinese PLA General Hospital between September 2015 and March 2017 with confirmed CS. The psychiatric scales and brain task functional magnetic resonance imaging (fMRI) were evaluated. Results: A total of 40 patients (34 females, 6 males) with a mean age of (39.20±12.10) years and a median education level of 12 (9, 16) years were enrolled. ACTH-dependent patients had significantly worse performance than the ACTH-independent patients in response to the depression evaluation (64.6±6.1 vs 56.2±12.8, P=0.008), positive emotion (17.8±4.2 vs 24.3±7.2, P=0.008) and CS life quality [31(29,33) vs 42(29,51), P=0.040]. In the reaction to positive target pictures, ACTH-dependent CS patients showed stronger activation in left superior temporal gyrus compared with patients in ACTH-independent group, while the activation degree of their bilateral dorsal anterior cingulate cortex, bilateralsuperior frontal gyrus and left middle frontal gyrus was much worse. In the reactions to negative target pictures, ACTH-dependent CS patients had weaker activation in bilateral cerebellum, left superior frontal gyrus, left middle frontal gyrus, left precuneus and right postcentral gyrus, compared with patients in the ACTH-independent CS group (P<0.01, AlphaSim corrected). The activation degree of some regions whose brain function was different between the two groups was correlated to the cortisol level, ACTH level, 24 h urinary free cortisol (UFC) level, depression evaluation and negative emotion assessment (all P<0.05). Conclusions: The severity of the depression and the life quality of patients in ACTH-dependent group are worse than ACTH-independent CS patients. The brain function of ACTH-dependent CS patients is much weaker.

Hepcidin is an endogenous protective factor for osteoporosis by reducing iron levels

Postmenopausal osteoporosis is a global health issue. Although a lack of estrogen is considered the major reason for postmenopausal osteoporosis, other factors might also contribute the etiology of the disease. In previous reports, we and others proposed that iron accumulation after menopause accelerates osteoporosis, and here, we genetically modified the expression of an endogenous hormone, hepcidin, to modulate iron status in a mouse model. Our results show that hepcidin levels negatively correlate with bone loss in both knockout and overexpression (with ovariectomy) murine models. In addition, iron overload enhances reactive oxygen species (ROS) activity and attenuates the functions of primary osteoblasts, while iron depletion could reverse this phenomenon through inhibiting the functions of primary osteoclasts. Therefore, our results provide more evidence of the 'iron accumulation' hypothesis, which suggests that high iron levels are risk factors for osteoporosis, and the 'Huang's hypothesis' that hepcidin is a potential drug target for the prevention of postmenopausal osteoporosis.