CADASIL as a Useful Medical Model and Genetic Form of Vascular Depression

Pathomechanisms of Vascular Depression in Older Adults

Depression in older individuals is a common complex mood disorder with high comorbidity of both psychiatric and physical diseases, associated with high disability, cognitive decline, and increased mortality The factors predicting the risk of late-life depression (LLD) are incompletely understood. The reciprocal relationship of depressive disorder and age- and disease-related processes has generated pathogenic hypotheses and provided various treatment options. The heterogeneity of depression complicates research into the underlying pathogenic cascade, and factors involved in LLD considerably differ from those involved in early life depression. Evidence suggests that a variety of vascular mechanisms, in particular cerebral small vessel disease, generalized microvascular, and endothelial dysfunction, as well as metabolic risk factors, including diabetes, and inflammation that may induce subcortical white and gray matter lesions by compromising fronto-limbic and other important neuronal networks, may contribute to the development of LLD. The "vascular depression" hypothesis postulates that cerebrovascular disease or vascular risk factors can predispose, precipitate, and perpetuate geriatric depression syndromes, based on their comorbidity with cerebrovascular lesions and the frequent development of depression after stroke. Vascular burden is associated with cognitive deficits and a specific form of LLD, vascular depression, which is marked by decreased white matter integrity, executive dysfunction, functional disability, and poorer response to antidepressive therapy than major depressive disorder without vascular risk factors. Other pathogenic factors of LLD, such as neurodegeneration or neuroimmune regulatory dysmechanisms, are briefly discussed. Treatment planning should consider a modest response of LLD to antidepressants, while vascular and metabolic factors may provide promising targets for its successful prevention and treatment. However, their effectiveness needs further investigation, and intervention studies are needed to assess which interventions are appropriate and effective in clinical practice.

Increased Notch2/NF-κB Signaling May Mediate the Depression Susceptibility: Evidence from Chronic Social Defeat Stress Mice and WKY Rats

The susceptibility to depression has been attributed to the chronic stress and genetic factors but still fails to identify definite biomarkers. The present study aimed to investigate the role of disrupted Notch signaling in the medial prefrontal cortex of the chronic social defeat stress (CSDS) mice and Wistar Kyoto (WKY) rats. RNA-sequencing and quantitative real-time PCR analyses evidenced the involvement of Notch signaling pathway in depression. Western blotting reported an increased level of Notch2 and NF-κB and a decreased level of Hes1 and Bcl2/Bax ratio both in the susceptible mice when compared with the control or resilient ones and in the depression WKY rats when compared with the Wistar or non-depression WKY groups. Further analysis showed that the above-mentioned changes were significantly correlated with the depression-like behaviors and that the elicited Notch2 strongly correlated with the upregulated NF-κB, not with the downregulated Hes1 or Bcl2/Bax ratio. In conclusion, the increased Notch2/NF-κB signaling in the medial prefrontal cortex may mediate depression susceptibility, providing a potential diagnostic biomarker or therapeutic target for treating major depressive disorder.

Common disbalance in the brain parenchyma of dementias: Phospholipid profile analysis between CADASIL and sporadic Alzheimer's disease

Sporadic Alzheimer's disease (SAD) is the most common form of dementia, and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most frequent hereditary ischemic small vessel disease of the brain. Relevant biomarkers or specific metabolic signatures could provide powerful tools to manage these diseases. Therefore, the main goal of this study was to compare the postmortem frontal cortex gray matter, white matter and cerebrospinal fluid (CSF) between a cognitively healthy group and CADASIL and SAD groups. We evaluated 352 individual lipids, belonging to 13 lipid classes/subclasses, using mass spectrometry, and the lipid profiles were subjected to multivariate analysis to discriminate between the dementia groups (CADASIL and SAD) and healthy controls. The main lipid molecular species showing greater discrimination by partial least squares-discriminant analysis (PLS-DA) and a higher significance multivariate correlation (sMC) index were as follows: phosphatidylserine (PS) PS(44:7) and lysophosphatidylethanolamine (LPE) LPE(18:2) in gray matter (GM); phosphatidylethanolamine (PE) PE(32:2) and phosphatidylcholine PC PC(44:6) in white matter (WM), and ether PE (ePE) ePE(38:2) and ether PC (ePC) ePC(34:3) in CSF. Common phospholipid molecular species were obtained in both dementias, such as PS(44:7) and lyso PC (LPC) LPC(22:5) in GM, PE(32:2) in WM and phosphatidic acid (PA) PA(38:5) and PC(42:7) in CFS. Our exploratory study suggests that phospholipids (PLs) involved in neurotransmission alteration, connectivity impairment and inflammation response in GM, WM and CSF are a transversal phenomenon affecting dementias such as CADASIL and SAD independent of the etiopathogenesis, thus providing a possible common prodromal phospholipidic biomarker of dementia.

Clinical and research applications of magnetic resonance imaging in the study of CADASIL

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is an inherited small vessel disease that leads to early cerebrovascular events and functional disability. It is the most common single-gene disorder leading to stroke. Magnetic resonance imaging (MRI) is a central component of the diagnosis and monitoring of CADASIL. Here we provide a descriptive review of the literature on three important aspects pertaining to the use of MRI in CADASIL. First, we review past research exploring MRI markers for this disease. Secondly, we describe results from studies investigating associations between neuroimaging abnormalities and neuropathology in CADASIL. Finally, we discuss previous findings relating MRI markers to clinical symptoms. This review thus provides a summary of the current state of knowledge regarding the use of MRI in CADASIL as well as suggestions for future research.

MRI Lesion Load of Cerebral Small Vessel Disease and Cognitive Impairment in Patients With CADASIL

Background and objective: Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the best known and the most common monogenic small vessel disease (SVD). Cognitive impairment is an inevitable feature of CADASIL. Total SVD score and global cortical atrophy (GCA) scale were found to be good predictors of poor cognitive performance in community-dwelling adults. We aimed to estimate the association between the total SVD score, GCA scale and the cognitive performance in patients with CADASIL. Methods: We enrolled 20 genetically confirmed CADASIL patients and 20 controls matched by age, gender, and years of education. All participants underwent cognitive assessments to rate the global cognition and individual domain of executive function, information processing speed, memory, language, and visuospatial function. The total SVD score and GCA scale were rated. Results: The CADASIL group performed worse than the controls on all cognition measures. Neither global cognition nor any separate domain of cognition was significantly different among patients grouped by total SVD score. Negative correlations between the GCA score and cognitive performance were observed. Approximately 40% of the variance was explained by the total GCA score in the domains of executive function, information processing speed, and language. The superficial atrophy score was associated with poor performance in most of the domains of cognition. Adding the superficial atrophy score decreased the prediction power of the deep atrophy score on cognitive impairment alone. Conclusions: The GCA score, not the total SVD score, was significantly associated with poor cognitive performance in patients with CADASIL. Adding the superficial atrophy score attenuated the prediction power of the deep atrophy score on cognitive impairment alone.

Effects of Cerebral Blood Flow and White Matter Integrity on Cognition in CADASIL Patients

Background: It remains unclear whether the degree of white matter tract damage or cerebral hypoperfusion can better predict global cognitive impairment in CADASIL. We sought to determine the independent effects of cerebral perfusion status and white matter integrity on the cognition. Methods: We reviewed prospectively collected clinical and imaging data from genetically-confirmed CADASIL patients who underwent both arterial spin labeling (ASL) perfusion MRI and diffusion tensor imaging (DTI). We analyzed the cerebral blood flow (CBF), mean diffusion (MD), and fractional anisotropy (FA) by dividing the brain tissue into white matter hyperintensity (WMH) and normal-appearing white matter (NAWM). Global cognitive function was evaluated by using Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). Results: Of the included 29 CADASIL patients, the mean age was 48.4 ± 7.9 years, and 17 (58.6%) were women. MD was significantly correlated with CBF in both WMH (r = -0.407, P = 0.035) and NAWM (r = -0.437, P = 0.023) after adjusting for age and WMH volume. A MoCA score was obtained in 13 patients and was significantly correlated with CBF in both WMH (r = 0.742, P = 0.004) and NAWM (r = 0.659, P = 0.014). Both CBF in WMH (area under the curve, 0.767; 95% CI, 0.586-0.947, P = 0.015) and MD in WMH (area under the curve, 0.740; 95% CI, 0.557-0.924, P = 0.028) were good predictors for cognitive impairment (MMSE score < 27). However, multiple linear regression analysis revealed that global cognitive function was independently associated with CBF in WMH only (standardized β = 0.485, P = 0.015), after adjusting for age, gender, WMH volume, the presence of subcortical infarcts and DTI metrics. Conclusions: Our findings suggested that cerebral hypoperfusion was more strongly associated with global cognitive dysfunction than the severity of brain microstructural damage, supporting that CBF assessed by ASL could serve as a candidate imaging indicator for monitoring alterations of global cognitive function in CADASIL.

Association Between Cerebral Microbleeds and Depression in the General Elderly Population: A Meta-Analysis

BACKGROUND

It remains unclear whether cerebral microbleeds (CMBs) are associated with depression in the general elderly population. We thus performed a meta-analysis to evaluate the relationship between depression and CMBs.

METHODS

A systematic literature search was conducted in EBSCO, PubMed, and Web of Science for relevant studies that assessed the relationship between depression and the prevalence of CMBs.

RESULTS

Five eligible studies including 7,328 patients were pooled in meta-analysis. The prevalence of CMBs was 18.0%. The prevalence of depression was 11.1%. The pooled analysis demonstrated odds ratio for CMBs and depression to be 1.187 (95% confidence interval 1.005-1.403; p = 0.043) with no evidence of statistical heterogeneity (I² = 0.0%, p = 0.621).

CONCLUSION

Our meta-analysis of available published data indicated an increased prevalence of depression in the subjects with pre-existing CMBs. This finding supports the vascular depression hypothesis. Further studies are needed to investigate the role of CMBs in the pathogenesis and progression of depression, which might provide a potential target for the prevention and treatment.