Choroid Plexus Dysfunction: The Initial Event in the Pathogenesis of Wernicke’s Encephalopathy and Ethanol Intoxication

Important Finding for COVID-19 Pandemic: Hydrocephalus-producing effect of Vaporized Alcohol Disinfectant

BACKGROUND

 Alcohol exposure may cause hydrocephalus, but the effect of vaporized nasal alcohol exposure on the choroid plexus, and ependymal cells, and the relationship between alcohol exposure and developing hydrocephalus are not well known. This subject was investigated.

METHODS

 Twenty-four male (∼380 g) Wistar rats were used in this study. The animals were divided into three groups, as the control, sham and study groups. The study group was further divided into two groups as the group exposed to low or high dose of alcohol. The choroid plexuses and intraventricular ependymal cells and ventricle volumes were assessed and compared statistically.

RESULTS

 Degenerated epithelial cell density of 22 ± 5, 56 ± 11, 175 ± 37, and 356 ± 85/mm3 was found in the control, sham, low alcohol exposure, and high alcohol exposure groups, respectively. The Evans index was <34% in the control group, >36% in the sham group, >40% in the group exposed to low alcohol dose (low-dose alcohol group), and >50% in the group exposed to high dose of alcohol (high-dose alcohol group).

CONCLUSIONS

 It was found that alcohol exposure caused choroid plexus and ependymal cell degeneration with ciliopathy and enlarged lateral ventricles or hydrocephalus. In the COVID-19 pandemic era, our findings are functionally important, because alcohol has often been used for hygiene and prevention of transmission of the Sars-Cov-2-virus.

Application of contrast-enhanced magnetic resonance imaging in the assessment of blood-cerebrospinal fluid barrier integrity

VERHEGGEN, I.C.M., W. Freeze, J. de Jong, J. Jansen, A. Postma, M. van Boxtel, F. Verhey and W. Backes. The application of contrast-enhanced MRI in the assessment of blood-cerebrospinal fluid barrier integrity. Choroid plexus epithelial cells form a barrier that enables active, bidirectional exchange between the blood plasma and cerebrospinal fluid (CSF), known as the blood-CSF barrier (BCSFB). Through its involvement in CSF composition, the BCSFB maintains homeostasis in the central nervous system. While the relation between blood-brain barrier disruption, aging and neurodegeneration is extensively studied using contrast-enhanced MRI, applying this technique to investigate BCSFB disruption in age-related neurodegeneration has received little attention. This review provides an overview of the current status of contrast-enhanced MRI to assess BCSFB permeability. Post-contrast ventricular gadolinium enhancement has been used to indicate BCSFB permeability. Moreover, new techniques highly sensitive to low gadolinium concentrations in the CSF, for instance heavily T2-weighted imaging with cerebrospinal fluid suppression, seem promising. Also, attempts are made at using other contrast agents, such as manganese ions or very small superparamagnetic iron oxide particles, that seem to be cleared from the brain at the choroid plexus. Advancing and applying new developments such as these could progress the assessment of BCSFB integrity.

Role of psychiatric, cardiovascular, socioeconomic, and demographic risk factors on idiopathic normal pressure hydrocephalus: A retrospective case-control study

OBJECTIVES

Currently, predicting and preventing idiopathic normal pressure hydrocephalus (iNPH) remains challenging, especially for patients without a history of cerebrovascular disease. By exploring the role of cardiovascular and psychiatric history, demographics, and socioeconomic status in iNPH, will provide better direction for elucidating the etiology or addressing healthcare inequalities.

PATIENTS AND METHODS

To investigate iNPH with respect to the selected risk factors, we conducted a retrospective case-control study from a neuroscience institute in Hawaii with a patient pool of 25,843. After excluding patients with a history of cerebrovascular disease, we identified 29 cases which meet the American-European guidelines for iNPH diagnosis. Meanwhile, 116 controls matched to age, sex, and race were also randomly selected.

RESULTS

Median age at diagnosis was 83 (IQR: 74-88), with cases estimated 22 years older than controls (95 % CI: 14.00-29.00; p = 0.0000001). Patients with iNPH were more likely to be White (OR 4.01, 95 % CI: 1.59-10.11; p = 0.0042) and less likely Native Hawaiian and other Pacific Islander (OR 0.010, 95 % CI: 0.00-0.78; p = 0.014). Median household income was $2874 (95 % CI: 0.000089-6905; p = 0.088) greater amongst iNPH cases. Effect size amongst cardiovascular risk factors was not found statistically significant (i.e., body mass index, hyperlipidemia, type 2 diabetes mellitus, hypertension, coronary artery disease or prior myocardial infarction history, peripheral vascular disease, smoking status, congestive heart failure, atrial fibrillation/flutter, and history of prosthetic valve replacement). However, iNPH patients were more likely to have a history of alcohol use disorder (OR 8.29, 95 % CI: 0.99-453.87; p = 0.050) and history of a psychiatric disorder (OR 2.48; 95 % CI: 1.08-5.68; p = 0.029). Odds ratio for autoimmune disorder, thyroid disorder, glaucoma, and seizures did not reach statistical significance.

CONCLUSION

Patient race (i.e., White; Native Hawaiian or other Pacific Islander) was found associated with iNPH development. Meanwhile, after excluding those with cerebrovascular disease, cardiovascular risk factors were not found associated with iNPH. Lastly, iNPH cases were more inclined to have a history of alcohol use disorder and prior psychiatric disorder. Overall, this data reveals that a racial disparity exists amongst iNPH, as well as highlights the role of various cardiovascular and psychiatric risk factors, which can potentially provide direction in etiology elucidation.

Clinical Imaging of Choroid Plexus in Health and in Brain Disorders: A Mini-Review

The choroid plexuses (ChPs) perform indispensable functions for the development, maintenance and functioning of the brain. Although they have gained considerable interest in the last years, their involvement in brain disorders is still largely unknown, notably because their deep location inside the brain hampers non-invasive investigations. Imaging tools have become instrumental to the diagnosis and pathophysiological study of neurological and neuropsychiatric diseases. This review summarizes the knowledge that has been gathered from the clinical imaging of ChPs in health and brain disorders not related to ChP pathologies. Results are discussed in the light of pre-clinical imaging studies. As seen in this review, to date, most clinical imaging studies of ChPs have used disease-free human subjects to demonstrate the value of different imaging biomarkers (ChP size, perfusion/permeability, glucose metabolism, inflammation), sometimes combined with the study of normal aging. Although very few studies have actually tested the value of ChP imaging biomarkers in patients with brain disorders, these pioneer studies identified ChP changes that are promising data for a better understanding and follow-up of diseases such as schizophrenia, epilepsy and Alzheimer’s disease. Imaging of immune cell trafficking at the ChPs has remained limited to pre-clinical studies so far but has the potential to be translated in patients for example using MRI coupled with the injection of iron oxide nanoparticles. Future investigations should aim at confirming and extending these findings and at developing translational molecular imaging tools for bridging the gap between basic molecular and cellular neuroscience and clinical research.

Association between shunt-responsive idiopathic normal pressure hydrocephalus and alcohol

OBJECTIVE Idiopathic normal pressure hydrocephalus (iNPH) is characterized by ventriculomegaly, gait difficulty, incontinence, and dementia. The symptoms can be ameliorated by CSF drainage. The object of this study was to identify factors associated with shunt-responsive iNPH. METHODS The authors reviewed the medical records of 529 patients who underwent shunt placement for iNPH at their institution between July 2001 and March 2015. Variables associated with shunt-responsive iNPH were identified using bivariate and multivariate analyses. Detailed alcohol consumption information was obtained for 328 patients and was used to examine the relationship between alcohol and shunt-responsive iNPH. A computerized patient registry from 2 academic medical centers was queried to determine the prevalence of alcohol abuse among 1665 iNPH patients. RESULTS Bivariate analysis identified associations between shunt-responsive iNPH and gait difficulty (OR 4.59, 95% CI 2.32-9.09; p < 0.0001), dementia (OR 1.79, 95% CI 1.14-2.80; p = 0.01), incontinence (OR 1.77, 95% CI 1.13-2.76; p = 0.01), and alcohol use (OR 1.98, 95% CI 1.23-3.16; p = 0.03). Borderline significance was observed for hyperlipidemia (OR 1.56, 95% CI 0.99-2.45; p = 0.054), a family history of hyperlipidemia (OR 3.09, 95% CI 0.93-10.26, p = 0.054), and diabetes (OR 1.83, 95% CI 0.96-3.51; p = 0.064). Multivariate analysis identified associations with gait difficulty (OR 3.98, 95% CI 1.81-8.77; p = 0.0006) and alcohol (OR 1.94, 95% CI 1.10-3.39; p = 0.04). Increased alcohol intake correlated with greater improvement after CSF drainage. Alcohol abuse was 2.5 times more prevalent among iNPH patients than matched controls. CONCLUSIONS Alcohol consumption is associated with the development of shunt-responsive iNPH.

Associations between in vivo neuroimaging and postmortem brain cytokine markers in a rodent model of Wernicke's encephalopathy

Thiamine (vitamin B1) deficiency, associated with a variety of conditions, including chronic alcoholism and bariatric surgery for morbid obesity, can result in the neurological disorder Wernicke's encephalopathy (WE). Recent work building upon early observations in animal models of thiamine deficiency has demonstrated an inflammatory component to the neuropathology observed in thiamine deficiency. The present, multilevel study including in vivo magnetic resonance imaging (MRI) and spectroscopy (MRS) and postmortem quantification of chemokine and cytokine proteins sought to determine whether a combination of these in vivo neuroimaging tools could be used to characterize an in vivo MR signature for neuroinflammation. Thiamine deficiency for 12days was used to model neuroinflammation; glucose loading in thiamine deficiency was used to accelerate neurodegeneration. Among 38 animals with regional brain tissue assayed postmortem for cytokine/chemokine protein levels, three groups of rats (controls+glucose, n=6; pyrithiamine+saline, n=5; pyrithiamine+glucose, n=13) underwent MRI/MRS at baseline (time 1), after 12days of treatment (time 2), and 3h after challenge (glucose or saline, time 3). In the thalamus of glucose-challenged, thiamine deficient animals, correlations between in vivo measures of pathology (lower levels of N-acetyle aspartate and higher levels of lactate) and postmortem levels of monocyte chemotactic protein-1 (MCP-1, also known as chemokine ligand 2, CCL2) support a role for this chemokine in thiamine deficiency-related neurodegeneration, but do not provide a unique in vivo signature for neuroinflammation.

The plant sterol brassicasterol as additional CSF biomarker in Alzheimer's disease

OBJECTIVE

Plant sterols (sitosterol, campesterol, stigmasterol and brassicasterol) are solely dietary-derivable sterols that are structurally very similar to cholesterol. In contrast to peripheral cholesterol, plant sterols can cross the blood-brain barrier and accumulate within mammalian brain. As an impaired function of the cerebrospinal fluid (CSF)-blood barrier is linked to neurodegenerative disorders, i.e. Alzheimer's disease (AD), we investigated whether this results in altered plant sterol concentrations in CSF.

METHOD

Applying gas chromatography/mass spectrometry analysis, plant sterol concentrations were measured in plasma and CSF of patients with AD (n = 67) and controls (n = 29). Age, gender, plasma-to-CSF albumin ratio, CSF Aβ(42) , CSF pTau, APOE4 genotype, and serum creatinine were applied as covariates in the statistical analysis for individual plant sterols in order to compare plasma and CSF plant sterol concentrations between patients with AD and controls.

RESULTS

Albumin quotient was a consistent predictor in CSF for cholesterol and methyl plant sterols campesterol and brassicasterol. Comparison of lipid parameters per diagnosis based on relevant predictors revealed significantly lower concentrations of brassicasterol (P < 0.001) in CSF of patients with AD. Binary logistic regression analysis revealed that brassicasterol improved the predictive value when added to pTau and Aβ42 in a biomarker model.

CONCLUSION

Brassicasterol might be a relevant additional biomarker in AD.

Choroid plexus: biology and pathology

The choroid plexus is an epithelial-endothelial vascular convolute within the ventricular system of the vertebrate brain. It consists of epithelial cells, fenestrated blood vessels, and the stroma, dependent on various physiological or pathological conditions, which may contain fibroblasts, mast cells, macrophages, granulocytes or other infiltrates, and a rich extracellular matrix. The choroid plexus is mainly involved in the production of cerebrospinal fluid (CSF) by using the free access to the blood compartment of the leaky vessels. In order to separate blood and CSF compartments, choroid plexus epithelial cells and tanycytes of circumventricular organs constitute the blood-CSF-brain barrier. As non-neuronal cells in the brain and derived from neuroectoderm, choroid plexus epithelia are defined as a subtype of macroglia. The choroid plexus is involved in a variety of neurological disorders, including neurodegenerative, inflammatory, infectious, traumatic, neoplastic, and systemic diseases. Abeta and Biondi ring tangles accumulate in the Alzheimer's disease choroid plexus. In multiple sclerosis, the choroid plexus could represent a site for lymphocyte entry in the CSF and brain, and for presentation of antigens. Recent studies have provided new diagnostic markers and potential molecular targets for choroid plexus papilloma and carcinoma, which represent the most common brain tumors in the first year of life. We here revive some of the classical studies and review recent insight into the biology and pathology of the choroid plexus.