Cholesterol profiling reveals 7ß-hydroxycholesterol as a pathologically relevant peripheral biomarker of Alzheimer's disease.

AIM: Cholesterol homeostasis is associated with Alzheimer's disease (AD). Despite the multitude of cholesterol metabolites, little is known about which metabolites are directly involved in AD pathogenesis and can serve as its potential biomarkers. METHODS: To identify "hit" metabolites, steroid profiling was conducted in mice with different age, diet, and genotype and also in humans with normal cognition, mild cognitive impairment, and AD using gas chromatography-mass spectrometry. Then, using one of the "hit" molecules (7ß-hydroxycholesterol; OHC), molecular and histopathological experiment and behavioral testing were conducted in normal mice following its intracranial stereotaxic injection to see whether this molecule drives AD pathogenesis and causes cognitive impairment. RESULTS: The serum levels of several metabolites, including 7ß-OHC, were increased by aging in the 3xTg-AD unlike normal mice. Consistently, the levels of 7ß-OHC were increased in the hairs of patients with AD and were correlated with clinical severity. We found that 7ß-OHC directly affects AD-related pathophysiology; intrahippocampal injection of 7ß-OHC induced astrocyte and microglial cell activation, increased the levels of pro-inflammatory cytokines (TNF-alpha, IL-1ß, IL-6), and enhanced amyloidogenic pathway. Mice treated with 7ß-OHC also exhibited deficits in memory and frontal/executive functions assessed by object recognition and 5-choice serial reaction time task, respectively. CONCLUSIONS: Our results suggest that 7ß-OHC could serve as a convenient, peripheral biomarker of AD. As directly involved in AD pathogenesis, 7ß-OHC assay may help actualize personalized medicine in a way to identify an at-risk subgroup as a candidate population for statin-based AD treatment.

Association of salivary testosterone levels during the post-awakening period with age and symptoms suggestive of late-onset hypogonadism in men.

BACKGROUND: The lack of association between serum testosterone levels and symptoms suggestive of hypogonadism is a significant barrier in the determination of late-onset hypogonadism (LOH) in men. This study explored whether testosterone levels increase after morning awakening, likewise the cortisol awakening response (CAR) in the hypothalamic-pituitary-adrenal (HPA) axis, and whether testosterone levels during the post-awakening period are associated with age and symptoms suggestive of late-onset hypogonadism (LOH) in men. METHODS: Testosterone and cortisol levels were determined in saliva samples collected immediately upon awakening and 30 and 60 min after awakening, and scores of the Aging Males' Symptoms (AMS) questionnaire were obtained from 225 healthy adult men. RESULTS: A typical CAR (an increase in cortisol level ≥ 2.5 nmol/L above individual baseline) was observed in 155 participants (the subgroup exhibiting typical CAR). In the subgroup exhibiting CAR, testosterone levels sharply increased during the post-awakening period, showing a significant negative correlation with age, total AMS score, and the scores of 11 items on the somatic, psychological, and sexual AMS subscales. Of these items, three sexual items (AMS items #15-17) were correlated with age. Meanwhile, there was no notable increase in testosterone levels and no significant correlation of testosterone levels with age and AMS score in the subgroup exhibiting no typical CAR (n = 70). CONCLUSIONS: The results indicate that the hypothalamus-pituitary-gonad (HPG) axis responds to morning awakening, and determining testosterone levels during the post-awakening period in men with typical CAR may be useful for assessing HPG axis function and LOH.

The present study found that the HPG axis in healthy adult men responds to the morning awakening, characterized by increased salivary testosterone levels after the awakening period.The levels of salivary testosterone during the first hour after awakening are negatively associated with age and the severity of symptoms suggestive of LOH in adult men with typical CAR.

Copycat Suicide Induced by Entertainment Celebrity Suicides in South Korea.

OBJECTIVE: Throughout the past several years, there have been a number of entertainment celebrity suicides in South Korea. The aim of this study was to investigate the clustering of suicides following celebrities' suicides in South Korea from 2005 to 2008, particularly according to certain characteristics. METHODS: Seven celebrity suicides were examined and defined using the Korean Integrated Newspaper Database System (KINDS) and from these, we considered four affected periods occurring 28 days after each celebrity's suicide. A Poisson time-series autoregression model was used to estimate the relative risk of the total suicide number for each affected period from 2005 to 2008. Logistic regression analysis was performed to investigate whether there were specific increases in the numbers of suicides in subgroups matching each celebrity. RESULTS: There were significant increases in the risk of suicide during the affected periods. Remarkable increases were found in the subgroups matching each celebrity, especially in the group in which all factors (sex, age, and method) were similar. CONCLUSION: This study provides confirmation that a significant copycat effect was induced by these celebrities' suicides, especially among people who identified more with the celebrities. This implies that countermeasures for upright media coverage of celebrity suicides should be discussed and practiced properly in South Korea.