Brain neuronal and glial damage during acute COVID-19 infection in absence of clinical neurological manifestations.

BACKGROUND: To assess whether SARS-CoV-2 infection may affect the central nervous system, specifically neurons and glia cells, even without clinical neurological involvement. METHODS: In this single centre prospective study, serum levels of neurofilament light chain (sNfL) and glial fibrillar acidic protein (sGFAp) were assessed using SimoaTM assay Neurology 2-Plex B Assay Kit, in 148 hospitalised patients with COVID-19 without clinical neurological manifestations and compared them to 53 patients with interstitial pulmonary fibrosis (IPF) and 108 healthy controls (HCs). RESULTS: Age and sex-corrected sNfL levels were higher in patients with COVID-19 (median log10-sNfL 1.41; IQR 1.04-1.83) than patients with IPF (median log10-sNfL 1.18; IQR 0.98-1.38; p<0.001) and HCs (median log10-sNfL 0.89; IQR 0.72-1.14; p<0.001). Likewise, age and sex-corrected sGFAP levels were higher in patients with COVID-19 (median log10-sGFAP 2.26; IQR 2.02-2.53) in comparison with patients with IPF (median log10-sGFAP 2.15; IQR 1.94-2.30; p<0.001) and HCs (median log10-sGFAP 1.87; IQR 0.64-2.09; p<0.001). No significant difference was found between patients with HCs and IPF (p=0.388 for sNfL and p=0.251 for sGFAp). In patients with COVID-19, a prognostic model with mortality as dependent variable (26/148 patients died during hospitalisation) and sNfl, sGFAp and age as independent variables, showed an area under curve of 0.72 (95% CI 0.59 to 0.84; negative predictive value (NPV) (%):80,positive predictive value (PPV)(%): 84; p=0.0008). CONCLUSION: The results of our study suggest that neuronal and glial degeneration can occur in patients with COVID-19 regardless of overt clinical neurological manifestations. With age, levels of sNfl and GFAp can predict in-hospital COVID-19-associated mortality and might be useful to assess COVID-19 patient prognostic profile.

Vitamin D in Neurological Diseases.

Vitamin D may have multiple effects on the nervous system and its deficiency can represent a possible risk factor for the development of many neurological diseases. Recent studies are also trying to clarify the different effects of vitamin D supplementation over the course of progressive neurological diseases. In this narrative review, we summarise vitamin D chemistry, metabolism, mechanisms of action, and the recommended daily intake. The role of vitamin D on gene transcription and the immune response is also reviewed. Finally, we discuss the scientific evidence that links low 25-hydroxyvitamin D concentrations to the onset and progression of severe neurological diseases, such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, migraine, diabetic neuropathy and amyotrophic lateral sclerosis. Completed and ongoing clinical trials on vitamin D supplementation in neurological diseases are listed.

The Role of TNF-α in Alzheimer's Disease: A Narrative Review.

This review analyzes the role of TNF-α and its increase in biological fluids in mild cognitive impairment, and Alzheimer's disease (AD). The potential inhibition of TNF-α with pharmacological strategies paves the way for preventing AD and improving cognitive function in people at risk for dementia. We conducted a narrative review to characterize the evidence in relation to the involvement of TNF-α in AD and its possible therapeutic inhibition. Several studies report that patients with RA and systemic inflammatory diseases treated with TNF-α blocking agents reduce the probability of emerging dementia compared with the general population. Animal model studies also showed interesting results and are discussed. An increasing amount of basic scientific data and clinical studies underscore the importance of inflammatory processes and subsequent glial activation in the pathogenesis of AD. TNF-α targeted therapy is a biologically plausible approach for cognition preservation and further trials are necessary to investigate the potential benefits of therapy in populations at risk of developing AD.

FOLR1 Gene Variation With Adult-Onset Cerebral Folate Deficiency and Stable Clinical and MRI Features up to 2 Years.

Objectives: The objective of this case report was to describe the first report of FOLR1 variants associated with adult-onset paucisymptomatic leukoencephalopathy associated with cerebral folate deficiency (CFD). Methods: Considering the patient's symptoms, a nonprogressive leukoencephalopathy was suspected. CSF 5-methyltetrahydrofolate levels were low (10 nmol/L, normal range 41-117). With no other identifiable causes, a genetic analysis was conducted, revealing a compound heterozygous FOLR1 variation (c.45G>T and c. 493+2T>C). Results: A 47-year-old man with a history of drug and alcohol abuse was admitted to the hospital for double vision and postural instability. MRI of the brain was performed, which showed bilateral leukoencephalopathy. Diffusion tensor imaging revealed a diffuse reduction in fractional anisotropy, suggesting microstructural changes. MRI of the brain and overall clinical picture were stable on subsequent serial examinations. Discussion: Scientific evidence supports the deleterious effect of c.45G>T and c.493+2T>C variations on the folate receptor-α (FRα) protein structure and function. The weakness of the expression and function of FRα without elimination of its function caused by specific compound heterozygous variations may explain the atypical features observed in our patient. Although rare, CFD should be considered in paucisymptomatic adult patients with stable diffuse MRI white matter changes.