Predicting the efficacy of donepezil intervention in Alzheimer's disease patients using regional homogeneity in the inferior orbitofrontal cortex.

BACKGROUND: Although donepezil is a commonly used drug for treating Alzheimer's disease (AD), the mechanisms by which it affects patients' functional brain activity, and thus modulates clinical symptoms, remain unclear. METHODS: In the present study, we used resting-state functional magnetic resonance imaging (MRI) and regional homogeneity (ReHo) to investigate the effects of donepezil on local brain activity in AD patients. Resting-state functional MRI data were collected from 32 subjects: 16 healthy controls and 16 AD patients. All 16 AD patients underwent 6 months of donepezil treatment and received two MRI scans (pre- and post-intervention). Analysis of covariance and post hoc analyses were used to compare ReHo differences among the healthy controls, pre-intervention AD patients, and post-intervention AD patients. Pearson correlation analysis was used to examine relationships between ReHo values in differential brain regions and clinical symptoms. RESULTS: Compared with healthy controls, post-intervention AD patients had reduced ReHo in the orbital part of the inferior frontal gyrus, and pre-intervention AD patients had reduced ReHo in the orbital part of the right inferior frontal gyrus. Pattern recognition models revealed that pre-intervention ReHo values in abnormal brain regions of AD patients were 76% accurate for predicting the efficacy of donepezil on cognitive function and 65% accurate for predicting its efficacy on depressive symptoms. CONCLUSIONS: These findings deepen our understanding of the brain mechanisms underlying the clinical efficacy of donepezil in AD patients, and provide a novel way to predict its clinical efficacy in such patients.

Abnormal functional connectivity of the habenula in mild cognitive impairment patients with depression symptoms revealed by resting-state functional magnetic resonance imaging.

BACKGROUND: Recent research suggests that abnormalities in the habenula (HB), a core area of the brain that transmits reward information, may be a determinant of depression. However, it is not clear whether the functional connectivity (FC) pattern of the mild cognitive impairment (MCI) with and without depression symptoms is abnormal. METHODS: In this study, we used resting-state functional magnetic resonance imaging (fMRI) to examine the FC pattern of the HB in MCI patients with depression symptoms (D-MCI). We acquired fMRI data from 54 subjects on a 3T MRI. Subjects collected included 16 patients with D-MCI, 18 patients with MCI with no depression, and 20 healthy controls. One way ANCOVA and post hoc t-test were used to compare the difference in FC strength between the three groups. RESULTS: The D-MCI group had altered FC between the left HB and the right superior temporal gyrus, right inferior frontal gyrus/opercular part, and right middle frontal gyrus. The D-MCI group had increased FC between the right HB and precuneus. CONCLUSIONS: These results suggest that the dysfunction of the HB-Default model network might be involved in the neural mechanism underlying depression in MCI.

[Effect of ginsenoside Rb1 on cerebral infarction volume and IL-1 beta in the brain tissue and sera of focal cerebral ischemia/reperfusion injury model rats].

OBJECTIVE: To investigate the effect of ginsenoside Rb1 on cerebral infarction volume as well as IL-1 beta in the brain tissue and sera of focal cerebral ischemia/reperfusion (I/R) injury model rats. METHODS: The I/R rat model was established by using thread according to Zea-Longa. SD rats were randomly divided into five groups, i.e., the sham-operation group, the model group, the low dose ginsenoside Rb1 (20 mg/kg) group, the medium dose ginsenoside Rb1 group (40 mg/kg), and the high dose ginsenoside Rb1 group (80 mg/kg), 12 in each group. Rats in the sham-operation group only received middle cerebral artery occlusion (MCAO) but without thread insertion. The MCAO model was prepared in the rest 4 groups, followed by MCAO2 h later. Ginsenoside Rb1 at each dose was peritoneally administrated to rats in corresponding groups immediately after cerebral ischemia. Equal volume of normal saline was administered to rats in the sham-operation group. Rats' cerebral infarction volume, integrals of neurologic defect degree, expression of IL-1 beta content in the brain tissue and sera were observed 24 h after 2-h cerebral I/R. RESULTS: In the model group, integrals of neurologic defect degree were improved (P < 0.01), IL-1 beta positive cells in the brain tissue increased and serum IL-1 beta content elevated (P < 0.05), when compared with the sham-operation group. In comparison of the model group, integrals of neurologic defect degree were lowered in the medium dose and high dose ginsenoside Rb1 groups (P < 0.05, P < 0.01). The cerebral infarction volume was all shrunken in each ginsenoside Rb1 group, IL-1 beta positive cells in the brain tissue decreased, and IL-1 beta content in serum reduced (P < 0.01, P < 0.05). Compared with the low dose ginsenoside Rb1 group, integrals of neurologic defect degree decreased, the cerebral infarction volume shrunken, and IL-1 beta content in serum reduced in the high dose ginsenoside Rb1 group (P < 0.01, P < 0.05). CONCLUSION: Ginsenoside Rb1 (20, 40, 80 mg/kg) might effectively release local cerebral ischemia by down-regulating the IL-1 beta expression.