RESUMO
BACKGROUND: Extracellular free water (FW) resulting from white matter degeneration limits the sensitivity of diffusion tensor imaging (DTI) in predicting Alzheimer's disease (AD). PURPOSE: To evaluate the sensitivity of FW-DTI in detecting white matter microstructural changes in AD. To validate the effectiveness of FW-DTI indices to predict amyloid-beta (Aß) positivity in mild cognitive impairment (MCI) subtypes. STUDY TYPE: Retrospective. POPULATION: Thirty-eight Aß-negative cognitively healthy (CH) controls (68.74 ± 8.28 years old, 55% female), 15 Aß-negative MCI patients (MCI-n) (68.87 ± 8.83 years old, 60% female), 29 Aß-positive MCI patients (MCI-p) (73.03 ± 7.05 years old, 52% female), and 29 Aß-positive AD patients (72.93 ± 9.11 years old, 55% female). FIELD STRENGTH/SEQUENCE: 3.0T; DTI, T1 -weighted, T2 -weighted, T2 star-weighted angiography, and Aß PET (18 F-florbetaben or 11 C-PIB). ASSESSMENT: FW-corrected and standard diffusion indices were analyzed using trace-based spatial statistics. Area under the curve (AUC) in distinguishing MCI subtypes were compared using support vector machine (SVM). STATISTICAL TESTS: Chi-squared test, one-way analysis of covariance, general linear regression analyses, nonparametric permutation tests, partial Pearson's correlation, receiver operating characteristic curve analysis, and linear SVM. A P value <0.05 was considered statistically significant. RESULTS: Compared with CH/MCI-n/MCI-p, AD showed significant change in tissue compartment indices of FW-DTI. No difference was found in the FW index among pair-wise group comparisons (the minimum FWE-corrected P = 0.114). There was a significant association between FW-DTI indices and memory and visuospatial function. The SVM classifier with tissue radial diffusivity as an input feature had the best classification performance of MCI subtypes (AUC = 0.91), and the classifying accuracy of FW-DTI was all over 89.89%. DATA CONCLUSION: FW-DTI indices prove to be potential biomarkers of AD. The classification of MCI subtypes based on SVM and FW-DTI indices has good accuracy and could help early diagnosis. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 2.
RESUMO
BACKGROUND: Polydatin and resveratrol are extractives of radix or rhizoma of Polygonum cuspidatum, and as the glycoside forms, it is a natural precursor of resveratrol. PURPOSE: In this study, we aimed to explore the mutual transformation between polydatin and resveratrol in rats, and to compare the antioxidative effect of them in vivo. STUDY DESIGN: In this study, we analyzed the serum molar concentration of polydatin and resveratrol after oral administration in rats and evaluated the anti-oxidative stress effects of them using a mouse model. METHODS: Rats were orally administered polydatin or resveratrol and the concentration of them in serum were analyzed by high performance liquid chromatography (HPLC). Their antioxidative effect was compared in mice with oxidative stress cardiomyopathy induced by doxorubicin (DOX). RESULTS: The results showed that polydatin and resveratrol could mutually transform in vivo, the molar concentration of polydatin in serum was always averagely 3.35 and 4.28 times as much as resveratrol after oral administration of polydatin and resveratrol at 200 mg/kg, respectively. Both polydatin and resveratrol could significantly decrease the content of malonydialdehyde (MDA), promote the activities of total superoxide dismutase (T-SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in plasma, and increase the content of glutathione (GSH) in myocardial tissue. The effect of polydatin surpassed resveratrol, particularly embodied in increasing the activities of T-SOD and CAT, and the content of GSH. CONCLUSION: It illustrates that polydatin is the main substance in serum after intragastric administration with polydatin or resveratrol, and the mutual transformation between polydatin and resveratrol keeps balance; they both have the ability of antioxidative stress in vivo, and polydatin has a better effect than resveratrol, which hints that polydatin may be a substitute for resveratrol in antioxidant for clinical use.
