Analysis of Risk Factors for Cerebral Microbleeds and the Relationship between Cerebral Microbleeds and Cognitive Impairment

(1) Background: Cerebral microbleeds (CMBs) are attracting increasing attention. Nevertheless, the risk factors for CMBs remain poorly identified, and the relationship between CMBs and cognitive impairment is still up for debate; (2) Objective: The present study analyzed the risk factors for CMBs and probed into the potential correlations between the presence, number, and location of CMBs and cognition; (3) Methods: This study enrolled 406 subjects who underwent both brain 3.0-T magnetic resonance imaging scans and cognitive testing. Spearman correlation was used to assess the relationship between the number of CMBs and cognition. Multiple linear regression was utilized to analyze the relationship between the regions of CMBs and each cognitive domain; (4) Results: Multivariate logistic regression analysis results showed that age (odds ratio (OR) = 1.045, 95% confidence interval (95%CI; 1.009, 1.082)), smoking (OR = 3.604, 95%CI (1.995, 6.509)), hypertension (OR = 3.607, 95%CI (2.204, 5.901)), total cholesterol (OR = 0.611, 95%CI (0.467, 0.799)), and Amyloid-β1-42 (Aβ1-42) (OR = 1.028, 95%CI (1.018, 1.037)) were the influencing factors of CMBs. Education years (OR = 0.959, 95%CI (0.930, 0.988)), white matter lesions (OR = 2.687, 95%CI (1.782, 4.051)), and CMBs (OR = 21.246, 95%CI (5.728, 21.576)) were the risk factors for cognitive impairment. Hypertension increased the probability of deep CMBs (OR = 12.54, 95%CI (2.21, 71.28)), while Aβ1-42 elevated the probability of lobar CMBs (OR = 1.02, 95%CI (1.00, 1.03)). There was a linear correlation between the number of CMBs and Montreal Cognitive Assessment scores (r = −0.756, p < 0.001). However, CMBs in each region were not related to specific cognitive domains (p > 0.05), except CMBs in the mixed group that were negatively correlated with attention (OR = −0.669, 95%CI (−0.034, −5.270)); (5) Conclusions: Taken together, serum Aβ1-42 levels are related to the presence of CMBs. Cognitive impairment is correlated with the number of CMBs rather than their region. These findings suggest that CMBs play a role in cognitive impairment and that CMBs mark the presence of diffuse vascular injury and neurodegenerative brain damage.

Contrasting effects of acute and long-term corticosterone treatment on amyloid-β, beta-secretase 1 expression, and nuclear factor kappa B nuclear translocation

Regulation of neuroinflammation is critical to control the detrimental impact of chronic stress in the central nervous system. Neuroinflammation occurs in response to chronic stress, leading to enhanced neuronal damage in the brain. We investigated the regulatory effects of stress hormone corticosterone on neuroinflammation regulator, as well as amyloid-β and Beta-secretase 1 related signaling. We demonstrate that corticosterone can both positively and negatively regulate amyloid-β expression, which may be related to the ratio of neuroinflammation regulator and Beta-secretase 1 signaling in rat primary cortical neurons. Thirty minutes of treatment with 1 μM corticosterone significantly decreased the nuclear translocation of neuroinflammation mediator neuroinflammation regulator (Western Blot: P < 0.05, Immunofluorescence: P < 0.001) and production of Beta-secretase 1 enzyme (P < 0.01), which was accompanied by a reduction in amyloid-β1-42 levels (P < 0.01). In contrast, 1 µM corticosterone treatment over 3 days increased nuclear neuroinflammation regulator localization (P < 0.001), followed by the upregulation of Beta-secretase 1 (P < 0.01) and amyloid-β1-42 (P < 0.05) expression. This work is the first to demonstrate that the duration of corticosterone exposure can promote or inhibit amyloid-β production, and to link this effect with Beta-secretase 1 / neuroinflammation regulator signaling, together with providing valuable insight into the mechanisms of neuroinflammation and neuroprotection.