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Intracerebral Hemorrhage-Induced Cognitive Impairment in Rats Is Associated With Brain Atrophy, Hypometabolism, and Network Dysconnectivity

ABSTRACT: The mechanisms underlying intracerebral hemorrhage (ICH)-related cognitive impairment (CI) remain unclear. Long-term structural and functional changes were investigated in the brains of healthy male and female Wistar rats after experimental ICH. Following double injection of autologous blood, rats underwent short-term (onset, 3 and 7 days) and long-term (3 and 6 months) radiological assessment and behavioral tests exploring spontaneous locomotion, anxiety-like behavior and working memory, spatial recognition memory and visual recognition memory. Volumetric and metabolic changes in brain areas were examined by 7Tesla-MRI and [18F] FDG-PET, respectively. Brain connectomic disorders and maladaptive processes were seeked through brain metabolic connectivity analysis and atrophy-related network analysis. From an initial hematoma mean volume of 23.35 ± 9.50 mm3, we found early spontaneous locomotor recovery and significant spontaneous blood resorption (≈ 40% of the initial lesion) from days 0 to 7. After 3 and 6 months, ICH rats exhibited CI in several domains as compared to the sham group (working memory: 58.1 ± 1.2 vs. 70.7 ± 1.2%, p < 0.001; spatial recognition memory: 48.7 ± 1.9 vs. 64 ± 1.8%, p < 0.001 and visual recognition memory: 0.14 ± 0.05 vs. 0.33 ± 0.04, p = 0.013, in female only). Rats that experienced ICH had remote and concomitant cerebral atrophy and hypometabolism of ipsilateral striatum, thalamus, limbic system and cortical areas (temporal and parietal lobes). Interestingly, both structural and metabolic deterioration was found in the limbic system connected to the affected site, but remotely from the initial insult. On the other hand, increased activity and functional connectivity occurred in the contralateral hemisphere. These connectomics results showed that both maladaptative and compensation processes coexist in the rat brain following ICH, even at young age and in a disease-free setting. These radiological findings deepen our understanding of ICH-related CI and may serve as biomarkers in the view of future therapeutic intervention.

SUBMITTER: Puy L

PROVIDER: S-EPMC9280302 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundCognitive impairment seems to be frequent in intracerebral hemorrhage (ICH) survivors, but remains widely understudied. In this study, we investigated the frequency and patterns of vascular cognitive disorders (VCDs) in patients with cerebral amyloid angiopathy (CAA)-related and deep ICH compared to patients with mild cognitive impairment due to Alzheimer's disease (MCI-AD) and healthy controls.MethodsWe prospectively recruited 20 patients with CAA-related lobar ICH, 20 with deep ICH, 20 with MCI-AD and 17 healthy controls. Patients with cognitive decline pre-ICH were excluded from the analysis. Each participant underwent a comprehensive neuropsychological assessment and a structural brain MRI. Cognitive assessment was performed at a median delay of 4 months after the acute phase in ICH patients, and more than 6 months after the first complaint in MCI-AD patients. Cognitive profiles were compared between groups. The prevalence of VCDs in the ICH groups was estimated using the recent VASCOG criteria.Results"Mild" and "major VCDs" were respectively observed in 87.5% and 2.5% of all ICH patients. Every patient in the CAA group had mild VCDs. No significant difference was observed in cognitive functioning between CAA-related and deep ICH patients. The most impaired process in the CAA group was naming, with a mean (±standard deviation) z-score of -5.2 ±5.5, followed by processing speed (-4.1±3.3), executive functioning (-2.6 ±2.5), memory (-2.4 ±3.5) and attention (-0.9 ±1.3). This cognitive pattern was different from the MCI-AD patients, but the groups were only different in gestural praxis, and by construction, in memory processes.ConclusionsVCDs are frequent after ICH. Cognitive patterns of patients with deep or CAA-related ICH did not differ, but there was impaired performance in specific domains distinct from the effects of Alzheimer's disease.Clinical trial registrationURL: http://www.clinicaltrials.gov. Unique identifier: NCT01619709.

Project description:The pathophysiological process underlying cognitive decline in Parkinson's disease is not well understood. Cerebral atrophy and hypometabolism have been described in patients with Parkinson's disease and dementia or mild cognitive impairment with respect to control subjects. However, the exact relationships between atrophy and hypometabolism are still unclear. To determine the extension and topographical distribution of hypometabolism and atrophy in the different cognitive states of Parkinson's disease, we examined 46 patients with Parkinson's disease (19 female, 27 male; 71.7 ± 5.9 years old; 14.6 ± 4.2 years of disease evolution; modified Hoehn and Yahr mean stage 3.1 ± 0.7). Cognitive status was diagnosed as normal in 14 patients, as mild cognitive impairment in 17 and as dementia in 15 patients. Nineteen normal subjects (eight female, 11 male; 68.1 ± 3.2 years old) were included as controls. (18)F-fluorodeoxyglucose positron emission tomography and magnetic resonance imaging scans were obtained, co-registered, corrected for partial volume effect and spatially normalized to the Montreal Neurological Institute space in each subject. Smoothing was applied to the positron emission tomography and magnetic resonance imaging scans to equalize their effective smoothness and resolution (10 mm and 12 mm full-width at half-maximum and Gaussian kernel, respectively). Z-score maps for atrophy and for hypometabolism were obtained by comparing individual images to the data set of control subjects. For each group of patients, a paired Student's t-test was performed to statistically compare the two Z-map modalities (P < 0.05 false discovery rate corrected) using the direct voxel-based comparison technique. In patients with mild cognitive impairment, hypometabolism exceeded atrophy in the angular gyrus, occipital, orbital and anterior frontal lobes. In patients with dementia, the hypometabolic areas observed in the group with mild cognitive impairment were replaced by areas of atrophy, which were surrounded by extensive zones of hypometabolism. Areas where atrophy was more extended than hypometabolism were found in the precentral and supplementary motor areas in both patients with mild cognitive impairment and with dementia, and in the hippocampus and temporal lobe in patients with dementia. These findings suggest that there is a gradient of severity in cortical changes associated with the development of cognitive impairment in Parkinson's disease in which hypometabolism and atrophy represent consecutive stages of the same process in most of the cortical regions affected.

Project description:Glucose metabolism reduction and brain volume losses are widely reported in Alzheimer's disease (AD). Considering that neuroimaging changes in the hippocampus and default mode network (DMN) are promising important candidate biomarkers and have been included in the research criteria for the diagnosis of AD, it is hypothesized that atrophy and metabolic changes of the abovementioned regions could be evaluated concurrently to fully explore the neural mechanisms underlying cognitive impairment in AD. Twenty-three AD patients and Twenty-four age-, sex- and education level-matched normal controls underwent a clinical interview, a detailed neuropsychological assessment and a simultaneous 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET)/high-resolution T1-weighted magnetic resonance imaging (MRI) scan on a hybrid GE SIGNA PET/MR scanner. Brain volume and glucose metabolism were examined in patients and controls to reveal group differences. Multiple linear regression models were employed to explore the relationship between multiple imaging features and cognitive performance in AD. The AD group had significantly reduced volume in the hippocampus and DMN regions (P < 0.001) relative to that of normal controls determined by using ROI analysis. Compared to normal controls, significantly decreased metabolism in the DMN (P < 0.001) was also found in AD patients, which still survived after controlling for gray matter atrophy (P < 0.001). These findings from ROI analysis were further confirmed by whole-brain confirmatory analysis (P < 0.001, FWE-corrected). Finally, multiple linear regression results showed that impairment of multiple cognitive tasks was significantly correlated with the combination of DMN hypometabolism and atrophy in the hippocampus and DMN regions. This study demonstrated that combining functional and structural features can better explain the cognitive decline of AD patients than unimodal FDG or brain volume changes alone. These findings may have important implications for understanding the neural mechanisms of cognitive decline in AD.

Project description:Background: Poststroke cognitive impairment (PSCI) has been increasingly recognized in patients, but some stroke survivors appear to show cognitive improvement beyond the acute stage. The risk factors associated with cognitive recovery after spontaneous intracerebral hemorrhage (ICH) onset have not yet been sufficiently investigated in prospective studies. Objective: We aimed to identify the trajectory of post-ICH cognitive impairment and the association of potential prognostic factors with follow-up cognitive recovery beyond early PSCI. Methods: In this stroke center-based cohort study, 141 consecutive dementia-free patients with spontaneous ICH were included and underwent Montreal Cognitive Assessment (MoCA) evaluation for cognitive function at baseline (within 2 weeks of ICH onset) and the shortened MoCA (short-MoCA) at a 6-month follow-up. To explore the prognostic factors associated with trajectory of cognition after an ICH onset, we adjusted for demographic and vascular risk factors, using multivariate logistic regression analysis. Results: Of the 141 ICH patients, approximately three quarters (106/141) were diagnosed with early PSCI (MoCA score <26) within 2 weeks of ICH onset. The multiple logistic regression indicated independent positive associations between risk of early PSCI and dominant-hemisphere hemorrhage [odd's ratio (OR): 8.845 (3.347-23.371); P < 0.001], mean corpuscular volume (MCV) [OR: 1.079 (1.002-1.162); P = 0.043], admission systolic blood pressure (sBP) [OR: 1.021 (1.005-1.038); P = 0.012]. Furthermore, 36% (33/90) of ICH survivors who had early PSCI exhibited cognitive recovery at the 6-month follow-up. After examining potential predictors through multiple linear regression based on stepwise, there were independent negative associations between cognitive recovery and dominant hemisphere hemorrhage [OR: 6.955 (1.604-30.162); P < 0.01], lobar ICH [OR: 8.363 (1.479-47.290); P = 0.016], years of education ? 9 [OR: 5.145 (1.254-21.105); P = 0.023], and MCV [OR: 1.660 (1.171-2.354); P = 0.004]. Baseline cognitive performance in the domains of visuospatial/executive function, attention, orientation, and language showed positive correlations with cognitive improvement (P < 0.05). Conclusion: In this cohort study of dementia-free survivors of ICH, our results show that one in three early PSCI survivors exhibit cognitive recovery, in relation to dominant-hemisphere hematoma, lobar ICH, educational history, and MCV levels. Future clinical trials including ICH survivors with cognitive dysfunction should assess these factors.

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Intracerebral Hemorrhage-Induced Cognitive Impairment in Rats Is Associated With Brain Atrophy, Hypometabolism, and Network Dysconnectivity

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