SIMOA-based analysis of plasma NFL levels in MCI and AD patients: a systematic review and meta-analysis.

BACKGROUND: The single-molecule array assay (SIMOA)-based detection of neurofilament light (NFL) chain could be useful in diagnosing mild cognitive impairment (MCI) and Alzheimer's disease (AD). This meta-analysis aimed to evaluate the circulating concentration of NFL in AD and MCI patients compared with healthy controls using the SIMOA technique. METHODS: To this end, Google Scholar, PubMed, Scopus, Web of Science, and the reference lists of relevant articles were systematically searched for studies reporting serum NFL chain levels in healthy controls, MCI, and AD patients. Appropriate statistical methods were employed to achieve the study purpose. RESULTS: Fifteen eligible studies including 3086 patients were pooled out of a total of 347 publications. Fixed effect model analysis showed that NFL chain level was significantly higher in the serum of patients with MCI (0.361 SMD, 95% CI, 0.286-0.435, p = 0.000, I2 = 49.179) and AD (0.808 SMD, 95% CI, 0.727-0.888, p = 0.000, I2 = 39.433) compared with healthy individuals. The analysis also showed that the NFL chain levels in plasma were significantly different between patients with MCI and AD (0.436 SMD, 95% CI, 0.359-0.513, p = 0.000, I2 = 37.44). The overall heterogeneity of the studies was modest. CONCLUSIONS: This study highlights the potential of serum NFL chain detected using SIMOA in differentiating MCI, AD, and healthy controls.

Effect of intranasal administration of caffeine on mPFC ischemia­induced cognitive impairment in BALB/c mice.

Caffeine is a psychoactive compound used widely to enhance cognitive functions in human or animal studies. The present study examined the effects of caffeine on cognitive performance and inflammatory factors in mice with medial prefrontal cortex (mPFC) ischemia. Mice underwent a photothrombotic mPFC ischemic stroke and were treated with normal saline or caffeine at different doses intranasally for 7 days. The sham surgery animals received normal saline intranasally. The Morris water maze test and social interaction test were performed to assess spatial and social memories, respectively. In addition, the levels of inflammatory proteins, including tumor necrosis factor­alpha, interleukin­6, and interleukin­10, were measured in the mPFC using immunoblotting. The results showed that mPFC ischemia impaired spatial memory and social behaviors, and caffeine at doses of 0.05 and 0.1 mg improved behavioral outcomes in the ischemic groups. Also, caffeine reversed ischemia­induced high levels of pro­inflammatory biomarkers and enhanced the expression of the anti­inflammatory mediator. Our findings indicate that caffeine alleviated mPFC ischemia­induced memory disturbances, probably through the modulation of the inflammatory mediators.