Neurochemical correlates of cognitive dysfunction in patients with leukoaraiosis: a proton magnetic resonance spectroscopy study

Reduced GABA concentration in patients with white matter hyperintensities

To investigate potential alterations of white matter hyperintensities (WMHs) on J-edited MR spectroscopy (MRS) measures of the primary inhibitory neurotransmitter γ-aminobutyric acid (GABA). Twenty-four WMHs patients and 20 healthy controls (HCs) were recruited to undergo magnetic resonance spectroscopy (MRS) scan at 3T from voxels in left centrum semiovale white matter, using the MEGA point resolved spectroscopy (MEGA-PRESS) technique with the MATLAB-based Gannet tool to estimate GABA+ co-edited macromolecule (GABA+) levels and using Tarquin software to estimate levels of glutamate + glutamine (Glx), total N-acetylaspartate (tNAA), total choline (tCho), and total creatine (tCr). Independent t-tests or Mann-Whitney U-tests were used to test group differences between WMHs and HCs. Additionally, WMHs patients were divided into mild and moderate-severe WMHs subgroup according to the Fazekas scale. Analysis of variance (ANOVA) and post-hoc tests were used among WMHs subgroups and HCs. We found there was a significant reduction in GABA+ levels (p = 0.018) in WMHs patients compared with healthy controls. In subgroup analyses, there was also a significant reduction of GABA+ levels in moderate-severe WMHs subgroup (p = 0.037) and mild WMHs subgroup (p = 0.047) when compared to HCs. Besides, the moderate-severe WMHs subgroup had significantly higher levels of tCho compared with healthy controls (p = 0.019). In conclusion, reduced GABA+ levels in WMHs patients and elevated tCho levels in moderate-severe WMHs were observed when compared with HCs. These results demonstrate that abnormalities of the GABAergic system and choline metabolism may contribute to the pathogenesis of WMHs.

The Clinical Utility of Leukoaraiosis as a Prognostic Indicator in Ischemic Stroke Patients

Stroke constitutes a major cause of functional disability with increasing prevalence among adult individuals. Thus, it is of great importance for both clinicians and stroke survivors to be provided with a timely and accurate prognostication of functional outcome. A great number of biomarkers capable of yielding useful information regarding stroke patients' recovery propensity have been evaluated so far with leukoaraiosis being among them. Literature research of two databases (MEDLINE and Scopus) was conducted to identify all relevant studies published between 1 January 2012 and 25 June 2022 that dealt with the clinical utility of a current leukoaraiosis as a prognostic indicator following stroke. Only full-text articles published in English language were included. Forty-nine articles have been traced and are included in the present review. Our findings highlight the prognostic value of leukoaraiosis in an acute stroke setting. The assessment of leukoaraiosis with visual rating scales in CT/MRI imaging appears to be able to reliably provide important insight into the recovery potential of stroke survivors, thus significantly enhancing stroke management. Yielding additional information regarding both short- and long-term functional outcome, motor recovery capacity, hemorrhagic transformation, as well as early neurological deterioration following stroke, leukoaraiosis may serve as a valuable prognostic marker poststroke. Thus, leukoaraiosis represents a powerful prognostic tool, the clinical implementation of which is expected to significantly facilitate the individualized management of stroke patients.

Research Progress on MRI for White Matter Hyperintensity of Presumed Vascular Origin and Cognitive Impairment

White matter hyperintensity of presumed vascular origin (WMH) is a common medical imaging manifestation in the brains of middle-aged and elderly individuals. WMH can lead to cognitive decline and an increased risk of cognitive impairment and dementia. However, the pathogenesis of cognitive impairment in patients with WMH remains unclear. WMH increases the risk of cognitive impairment, the nature and severity of which depend on lesion volume and location and the patient's cognitive reserve. Abnormal changes in microstructure, cerebral blood flow, metabolites, and resting brain function are observed in patients with WMH with cognitive impairment. Magnetic resonance imaging (MRI) is an indispensable tool for detecting WMH, and novel MRI techniques have emerged as the key approaches for exploring WMH and cognitive impairment. This article provides an overview of the association between WMH and cognitive impairment and the application of dynamic contrast-enhanced MRI, structural MRI, diffusion tensor imaging, 3D-arterial spin labeling, intravoxel incoherent motion, magnetic resonance spectroscopy, and resting-state functional MRI for examining WMH and cognitive impairment.

Citicoline for Supporting Memory in Aging Humans

Citicoline is the generic name of CDP-choline, a natural metabolite present in all living cells. Used in medicine as a drug since the 1980-s, citicoline was recently pronounced a food ingredient. When ingested, citicoline breaks down to cytidine and choline, which become incorporated into their respective normal metabolic pathways. Choline is a precursor of acetylcholine and phospholipids; these is a neurotransmitter pivotal for learning and memory and important constituents of neuronal membranes and myelin sheaths, respectively. Cytidine in humans is readily converted to uridine, which exerts a positive effect on synaptic function and supports the formation of synaptic membranes. Choline deficiency has been found to be correlated with memory dysfunction. Magnetic resonance spectroscopy studies showed that citicoline intake improves brain uptake of choline in older persons, suggestive of that it shall help in reversing early age-related cognitive changes. In randomized, placebo-controlled trials of cognitively normal middle-aged and elderly persons, positive effects of citicoline on memory efficacy were found. Similar effects of citicoline on memory indices were also found in patients suffering from mild cognitive impairment and some other neurological diseases. Altogether, the aforementioned data provide complex and unambiguous evidence supporting the claim that oral citicoline intake positively influences memory function in humans who encounter age-related memory impairment also in the absence of any detectable neurological or psychiatric disease.

White matter lesions are associated with obstructive sleep apnea hypopnea syndrome

BACKGROUND

Study on the association of white matter lesions with obstructive sleep apnea hypopnea syndrome and its risk factors.

METHODS

A recruited study with a sample of 172 patients from the department of neurology of the Third Affiliated Hospital of Southern Medical University between 2015 and 2019.

RESULTS

According to the univariate analysis, the independent variables where P < 0.1 were included in the multivariate logistic regression model. After adjusting for confounding factors, the two-category logistic regression showed that Obstructive sleep apnea hypopnea syndrome (OSAHS) (OR = 8.347, 95%CI: 2.561 ~ 27.212, P < 0.001) were independent risk factors for WML, and that the prevalence of Cerebral white matter lesions (WML) increased with the severity of OSAHS (P = 0.002). In the non-OSAHS group, the mild OSAHS group, and the moderate-to-severe OSAHS group the apnea-hypopnea index (AHI) in the supine position was significantly higher than that in the left or right lateral position, showing a decreasing trend. The SaO2 < 90% total sleep time (TST SaO2 < 90%) showed an increasing trend, as did the body mass index. In the OSAHS severity groups, the AHI in the supine position was significantly higher than that in the left or right lateral position. Spearman correlation analysis showed that WML was positively related to AHI in the supine position (r = 0.209, P = 0.006).

CONCLUSIONS

OSAHS was an independent risk factor for WML. There was a positive relationship between WML and AHI in the supine position.

ABBREVIATIONS

AHI, apnea-hypopnea index; OSAHS, obstructive sleep apnea hypopnea syndrome; WML, white matter lesions; MRI, magnetic resonance imaging; BMI, body mass index; TSTSaO2 <90%, SaO2 <90% total sleep time; LSaO2, lowest oxygen saturation level; CI, confidence interval; OR, odds ratio.

Total MRI burden of cerebral vessel disease correlates with the progression in patients with acute single small subcortical strokes

BACKGROUND

The patients of single small subcortical strokes (SS) commonly have neurological worsening with risk factors, and mechanisms remain unclear. Asymptomatic lacunes, white matter lesions, cerebral microbleeds, and enlarged perivascular spaces are MRI markers of cerebral small vessel disease (cSVD). Previous studies mostly explored the association between the neurological deterioration and presence of above markers separately. The relationship between progressive single small SS and the simultaneous presence of multiple markers of cSVD has not been fully identified. We aimed to investigate whether total burden of cSVD detected with MRI was associated with progressive small SS in this study.

METHODS

Patients with single small SS (2.0 cm in diameter) were prospectively recruited during January 2016 and May 2018. Progression was defined as worsening by ≥1 point in National Institutes Health Stroke Scale (NIHSS) motor score within 72 hr from onset. The presence and burden of cSVD were determined by brain MRI, producing a score between 0 and 4. Besides, the patients' characteristics, clinical data, medical treatments during hospitalization stay were collected and statistically analyzed. Associations with progression were tested with forward stepwise regression analyses.

RESULTS

Fifty-seven (35.6%) patients underwent progression. No significant difference was observed in the distribution of any single vascular risk factor and its related laboratory data among these patients. After adjustment for age, sex, NIHSS score at admission, and time from stroke to MRI in separate models, severe WMHs (OR = 4.892; 95% CI = 2.011-11.904, p = 0.016), moderate- and high-grade basal ganglia EPVS (OR = 2.970; 95% CI = 1.861-6.121, p = 0.009), and total cSVD score (OR = 3.359; 95% CI = 2.016-5.599, p = 0.010) were associated with progression.

CONCLUSION

This study demonstrated that total MRI cSVD burden was independently associated with progression after single small subcortical strokes.

Use of Multimodal Magnetic Resonance Imaging Techniques to Explore Cognitive Impairment in Leukoaraiosis

Leukoaraiosis, also referred to as white-matter hyperintensities (WMHs) or age-related white matter changes, is the most frequently seen lesion on brain magnetic resonance images (MRI) in the elderly. LA is a subject of intense research interest, and is correlated with stroke, cognitive impairment or dementia, disturbances, affective disorders, and poor prognoses. Rapid advances in neuroimaging have enabled greater understanding of LA associated with aging-related cognitive decline or dementia. Recently, the techniques of multimodal MRI, such as structural MRI (sMRI), resting-state functional MRI (rs-MRI), cerebrovascular reactivity (CVR), diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS), and dynamic contrast-enhanced MRI (DCE-MRI), have been used to explore the underlying mechanism of cognitive impairment in patients with LA. These multimodal MRI techniques may provide further insights into the structural and functional changes of LA with cognitive dysfunction.