ABSTRACT
Objective: Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive deterioration of memory and cognition. Mild cognitive impairment (MCI) has been implicated as a prodromal phase of AD. Although abnormal functional connectivity (FC) has been demonstrated in AD and MCI, the clinical differentiation of AD, MCI, and normal aging remains difficult, and the distinction between MCI and normal aging is especially problematic. We hypothesized that FC between the hippocampus and other brain structures is altered in AD and MCI, and that measurement of abnormal FC could have diagnostic utility for the classification of different AD stages. Methods: Elderly adults aged 60-85 years were assigned to AD, MCI, or normal control (NC) groups based on clinical criteria. Functional magnetic resonance scanning was completed by 119 subjects. Five dimension reduction/classification methods were applied, using hippocampus-derived FC strengths as input features. Classification performance of the five dimensionality reduction methods was compared between AD, MCI, and NC groups. Results: FCs between the hippocampus and left insula, left thalamus, cerebellum, right lingual gyrus, posterior cingulate cortex, and precuneus were significantly reduced in AD and MCI. Support vector machine learning coupled with sparse principal component analysis demonstrated the best discriminative performance, yielding classification accuracies of 82.02% (AD vs. NC), 81.33% (MCI vs. NC), and 81.08% (AD vs. MCI). Conclusion: Hippocampus-seed-based FCs were significantly different between AD, MCI, and NC groups. FC assessment combined with widely used machine learning methods can improve AD differential diagnosis, and may be especially useful to distinguish MCI from normal aging.
ABSTRACT
KIBRA rs17070145 polymorphism is associated with variations in memory function and the microstructure of related brain areas. Diffusion kurtosis imaging (DKI) as an extension of diffusion tensor imaging that can provide more information about changes in microstructure, based on the idea that water diffusion in biological tissues is heterogeneous due to structural hindrance and restriction. We used DKI to explore the relationship between KIBRA gene polymorphism and brain microstructure in young adults. We recruited 100 healthy young volunteers, including 53 TT carriers and 47 C allele carriers. No differences were detected between the TT homozygotes and C-allele carriers for any diffusion and kurtosis parameter. These results indicate KIBRA rs17070145 polymorphism likely has little or no effect on brain microstructure in young adults.
ABSTRACT
The present study aims to investigate the effects of soluble endoglin (sEng) on invasive ability of cultured cytotrophoblasts of first trimester of pregnancy. Cytotrophoblasts of normal 6 to 8-week pregnancy were cultured by trypsin digestion method, and were incubated with cell culture medium without (control group) and with 10 µg/L sEng (sEng group), respectively for 24 h. The invasive ability was determined by transwell invasion assay, and expressions of MMP-2, MMP-9 mRNA and protein were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively. The results showed that the invasive ability of cytotrophoblasts in sEng group was lower than that in control group (P < 0.05). Compared with control group, the expressions of MMP-2 and MMP-9 mRNA and protein of cytotrophoblasts were significantly lower (P < 0.05). In conclusion, sEng may participate in the genesis of preeclampsia by affecting the invasive ability of cytotrophoblasts through regulation of the expression of MMP-2 and MMP-9.
