Background: Loss of function of triggering receptor expressed on myeloid cell 2 (TREM2), a key receptor selectively expressed by microglia in the brain, contributes to the development of Alzheimer's disease (AD). Whether TREM2 levels are pathologically altered during the preclinical phase, and whether cerebrospinal fluid (CSF) soluble TREM2 protein (sTREM2) has a relationship with major pathological processes including Aβ and tau deposition are still unclear.Methods: According to the NIA-AA criteria, 659 cognitively normal participants from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) cohort were divided into four groups, stage 0 (normal Aβ 1-42 , T-tau and P-tau), stage 1 (low Aβ 1-42 , normal T-tau and P-tau), stage 2 (low Aβ 1-42 and high T-tau or P-tau), and suspected non-AD pathology (SNAP) (normal Aβ 1-42 and high T-tau or P-tau), to examine changes of CSF sTREM2 in the preclinical AD. Biomarker cut-off was based on the assumption that one-third of adults with normal cognition have AD pathology.Results: The level of CSF sTREM2 in the stage 1 decreased compared with the stage 0 (P < 0.001), and then increased in the stage 2 (P = 0.008). SNAP individuals also had significantly increased CSF sTREM2 (P < 0.001). Results of multiple linear regressions also showed positive correlations of CSF sTREM2 with Aβ 1-42 (β = 0.192, P < 0.001), T-tau (β = 0.215, P < 0.001) and P-tau (β = 0.123, P < 0.001).Conclusion: CSF sTREM2 levels are dynamic in preclinical AD. Aβ pathology is associated with a decrease in CSF sTREM2 in the absence of tau deposition and neurodegeneration. However, tau pathology and neurodegeneration are associated with an increase in CSF sTREM2.

Introduction This study tested the self‐reported sleep characteristics associated with cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers in cognitively intact older adults. Methods The linear and non‐linear regression analyses were conducted in 736 cognitively normal participants (mean [standard deviation; SD] age, 62.3 [10.5] years, range 40 to 88 years, 59% female) who had measurements of cerebrospinal fluid (CSF) amyloid beta (Aβ) and tTau proteins and sleep characteristics, after adjusting for age, gender, education, apolipoprotein E gene (APOE) ε4 status, and general cognition. Results Greater daytime sleepiness was associated with higher CSF indicators of amyloid deposition in female patients. No significant associations were revealed for CSF tTau proteins after Bonferroni correction. A U‐shaped relationship was revealed for nocturnal sleep habits, such that those with insufficient or excessive nocturnal sleep duration had greater CSF biomarkers of amyloid deposition (the reflection range: bedtime: around 10:00 p.m. and sleep duration: 6.0 to 6.5 hours). Discussion These findings consolidated the close relationship between sleep and AD.

Background: Alzheimer's disease, the most common form of dementia, has tremendous social and economic impact worldwide. This study aimed to analyze global trends in Alzheimer's disease research and to investigate China's contribution to this research. Methods: The quantity and influence of publications related to Alzheimer's disease in China and elsewhere were compared. The Web of Science (WOS) and PubMed databases were searched from 1988 to 2017 using the terms “Alzheimer's disease” or “Alzheimers disease.” Global Alzheimer's disease publications were classified and analyzed. Keywords, countries, and institutions publishing articles on Alzheimer's disease were analyzed, and citations of these articles were examined. Results: A total of 181,116 articles regarding Alzheimer's disease research were identified and analyzed. Neuroscience and neurology were the main research categories both globally and in China. Basic research dominated Alzheimer's publications, accounting for 30.93% of global publications and 95.31% of publications in China. A total of 8,935 journals published articles related to Alzheimer's disease. The journal Neurobiology of Aging published the most Alzheimer's disease-related articles, numbering 5,206 over the time period examined. The National Institutes of Health, the National Institute on Aging, and the Department of Health and Human Services jointly sponsored 11,809 articles, ranking first in the world. The National Natural Science Foundation of China funded the largest number of studies on Alzheimer's disease in China and recognized the importance of traditional Chinese medicine in Alzheimer's disease research. Conclusions: The present study provides data for global researchers to understand research perspectives and develop future research directions. In recent years, Chinese researchers have contributed significantly to global Alzheimer's research. Still, strengthening international cooperation could improve the quality and number of publications regarding Alzheimer's disease.

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Increasing evidences supported that subjective cognitive decline (SCD) might be a potential first symptomatic manifestation of Alzheimer’s disease (AD). The rapidly growing number of SCD individuals who seek medical help and advice also makes it urgent to develop more precise strategy for SCD. Therefore, this study aimed to explore the risk factors for SCD. Logistics and linear regression models were performed to investigate 41 factors for SCD in 1165 participants without objective cognitive impairment. Cochran-Armitage trend test was used to confirm the constant trend toward higher prevalence of SCD with an increasing number of risk factors. A high overall prevalence of SCD was found in total participants (42%). Eight factors were eventually identified as risk factors for SCD, including four stable factors associated with both SCD statues and severity (older age, thyroid diseases, minimal anxiety symptoms, and day time dysfunction; odds ratio (OR) ranging from 1.74 to 2.29) as well as four suggestive factors associated with either SCD statues or severity (female sex, anemia, lack of physical exercises, and living alone; OR ranging from 1.30 to 2.29). The prevalence of SCD gradually increased with the number of risk factors clustering increased in individuals (p for trend <0.001). Five of these eight factors were further proved among individuals with SCD-plus features. These findings revealed several risk factors for SCD, providing some new clues for formulating priority strategies for early prevention of SCD.

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Objective: To examine whether apolipoprotein B (ApoB), apolipoprotein A-1 (ApoA1), or their ratio (ApoB/A1) were associated with early changes in cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) pathology in elderly adults with subjective cognitive decline (SCD). Methods: This study included 507 objective cognitive normal participants from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) database including 288 cognitive normal participants (CN) and 219 SCD. Multiple linear regression models were used to examine the associations of apolipoproteins with CSF AD biomarkers. Results: Compared with control group, SCD participants with significant AD biological characteristics had lower ApoB levels (P = 0.0461). In total participants, lower level of serum ApoB was associated with decreases in CSF Ab42 (P = 0.0015) and Ab42/40 (P = 0.0081) as well as increases in CSF p-tau/Ab42 (P < 0.0001) and t-tau/Ab42 (P = 0.0013), independent of APOEɛ4 status. In further subgroup analysis, these associations were more significant in SCD participants (ApoB 9 Diagnose: P < 0.05). In addition, lower levels of ApoB were also found associated with increases in p-tau in the SCD subgroup (P = 0.0263). Furthermore, these protective associations were more significant in the overweight participants (ApoB 9 weight: P < 0.05). Results showed no association between ApoA1 and CSF biomarkers. Interpretation: This study is the first to find protective associations of serum ApoB with CSF AD core biomarkers, especially in SCD individuals. It indicated that ApoB may be a potential biomarker for preclinical AD and may play different roles in different stages of AD.

It was unclear whether sex hormone-binding globulin (SHBG) was a circulating biomarker of Alzheimer’s disease (AD). We tested the cross-sectional relationships between plasma SHBG and cerebrospinal fluid (CSF) AD biomarkers in 707 non-demented adults. Next, the influences of plasma SHBG on dynamic changes of CSF Aβ42, hippocampus volume, brain metabolism, and cognition were explored in 448 non-demented adults from the Alzheimer’s disease Neuroimaging Initiative (ADNI). Finally, the predictive and diagnostic values of plasma SHBG in AD were explored. A positive correlation was found between SHBG levels in plasma and CSF. Individuals with higher plasma SHBG levels had lower CSF Aβ42 (p < 0.005), after adjusting for age, gender, education, APOE 4 allele, and cognitive scores. Though no significant difference of plasma SHBG was observed between mild AD dementia and healthy normal, plasma SHBG could contribute to accelerated rates of CSF Aβ42 decrease (p < 0.0005), decline in brain metabolism (p < 0.05), and hippocampus atrophy (p < 0.01), cognitive decline (p < 0.01), as well as higher risk of AD dementia (p < 0.05). These findings indicated plasma SHBG could be a prodromal biomarker to predict disease progression in AD.