Cerebrospinal fluid biomarkers in SARS-CoV-2 patients with acute neurological syndromes.

BACKGROUND AND PURPOSE: Mechanisms underlying acute brain injury in SARS-CoV-2 patients remain poorly understood. A better characterization of such mechanisms remains essential to preventing long-term neurological sequelae. Our present aim was to study a panel of biomarkers of neuroinflammation and neurodegeneration in the cerebrospinal fluid (CSF) of NeuroCOVID patients. METHODS: We retrospectively collected clinical and CSF biomarkers data from 24 NeuroCOVID adults seen at the University Hospital of Guadeloupe between March and June 2021. RESULTS: Among 24 NeuroCOVID patients, 71% had encephalopathy and 29% meningoencephalitis. A number of these patients also experienced de novo movement disorder (33%) or stroke (21%). The CSF analysis revealed intrathecal immunoglobulin synthesis in 54% of NeuroCOVID patients (two with a type 2 pattern and 11 with a type 3) and elevated neopterin levels in 75% of them (median 9.1nM, IQR 5.6-22.1). CSF neurofilament light chain (NfL) was also increased compared to a control group of non-COVID-19 patients with psychiatric illnesses (2905ng/L, IQR 1428-7124 versus 1222ng/L, IQR 1049-1566). Total-tau was elevated in the CSF of 24% of patients, whereas protein 14-3-3, generally undetectable, reached intermediate levels in two patients. Finally, CSF Aß1-42 was reduced in 52.4% of patients (median 536ng/L, IQR 432-904) with no change in the Aß1-42/Aß1-40 ratio (0.082, IQR 0.060-0.096). CONCLUSIONS: We showed an elevation of CSF biomarkers of neuroinflammation in NeuroCOVID patients and a rise of CSF NfL, evocative of neuronal damage. However, longitudinal studies are needed to determine whether NeuroCOVID could evolve into a chronic neurodegenerative condition.

A combination of total tau and neurofilaments discriminates between neurodegenerative and primary psychiatric disorders.

BACKGROUND AND PURPOSE: Neuropsychiatric symptoms are commonly observed in neurodegenerative diseases. No biomarker is currently available to diagnose psychiatric conditions. As a consequence, the distinction between psychiatric and neurodegenerative disorders can be challenging in daily practice. METHODS: This retrospective study included a cohort of 64 primary psychiatric patients (PSY) and 162 patients suffering from various neurodegenerative disorders (NDG). Total tau (t-Tau), phosphorylated tau (p-Tau), Aß1-42 peptide (Aß1-42) and neurofilament light chain protein (NfL) were analysed in cerebrospinal fluid. The discrimination between PSY and NDG patients was assessed using both individual and combined analysis of cerebrospinal fluid markers. RESULTS: Cerebrospinal fluid t-Tau and NfL exhibited the best diagnostic performances: they were able to discriminate between PSY and each subgroup of NDG patients. t-Tau had the highest sensitivity (93.8%) but a poor specificity (67.3%). Indeed, some NDG subgroups exhibited low t-Tau levels comparable to PSY patients. A sequential combination t-Tau + NfL improved the characterization of patients, especially in these particular subgroups, increasing specificity up to 89.6% without modification of sensitivity. Finally, this combination of markers led to a high classification rate of 90.7% for the whole cohort of patients. CONCLUSION: The sequential combination t-Tau + NfL enables the biological detection of neurodegeneration in patients with psychiatric features. This association of markers seems to be a promising strategy for a differential diagnosis in clinical practice between primary psychiatric conditions and neurodegenerative disorders, thus improving medical care of patients.

Detection of CSF 14-3-3 Protein in Sporadic Creutzfeldt-Jakob Disease Patients Using a New Automated Capillary Western Assay.

Sporadic Creutzfeldt-Jakob disease (sCJD) is a fatal rapidly progressive dementia. The detection of 14-3-3 protein in cerebrospinal fluid (CSF) is included in the WHO diagnostic criteria for the pre-mortem diagnosis of CJD. The aim of this study is to assess CSF 14-3-3 protein analytical and diagnostic performances using a new automated capillary Western technology (Simple Western technology-SW). For the validation of this assay, samples from a cohort of 268 patients suspected from sCJD were analyzed: 77 sCJD (including 40 definite sCJD) and 191 non-CJD samples were tested using both SW and the current Western Blot (WB) assays. Automated capillary Western determination provided better analytical performances than WB with a lower intra- and inter-assay variability. Analytical interferences such as hemolysis and high total protein concentration known to lead to false positive WB results were also assessed using SW assay: unfortunately, these interferences still remain confounders of CSF 14-3-3 protein determination. Finally, automated capillary Western assay's sensitivity and specificity were superior to those of WB assay (93.5 and 95.3%, respectively, compared to 92.2 and 84.8% for WB). In conclusion, with a shorter time of analysis than WB assays' (4 h versus 1.5 day), automated capillary Western assay is an excellent routine alternative method to the currently performed WB assay for CSF 14-3-3 protein detection in patients suspected of sporadic Creutzfeldt-Jakob disease.

How to control the recombinant prion protein adhesion for successful storage through modification of surface properties.

Depletion of neuroproteins on the inner walls of storage tubes influences the accuracy of tests used for identification of various neurodegenerative disorders. In this paper, a strategy is described for surface modification of Eppendorf tubes leading to non-adhesive properties towards the recombinant human prion proteins (PrPrec(hum)). Tubes were pre-activated by helium plasma and grafted with three diverse coatings: pure poly(N-isopropylacrylamide) (PNIPAM), PNIPAM admixed with either neutral PEG(20)sorbitan monolaurate (PEG(20)) or positively charged cetyl trimethylammonium bromide (CTAB) at varying plasma activation times and polymer to surfactant ratios. New functionalized surfaces were analyzed by goniometry, streaming potential measurement and X-ray photoelectron spectroscopy, whereas the protein adhesion was monitored by enzyme linked immunosorbent assays and confocal microscopy. The mapping of PrPrec(hum) adhesion associated with surface analyses enabled us to determine that no or negligible depletion of PrPrec(hum) can be obtained by surfaces possessing basic component in the range between 50 and 60 mJ m(-2) and streaming potential ζ(7.4) - -50 mV.

Improvement of the detection of neurodegenerative Alzheimer's disease through a specific surface chemistry applied onto the inner surface of the titration well.

The main objective of this paper was to illustrate the enhancement of the sensitivity of the ELISA titration of Tau proteins while reducing other non-specific adsorptions that could increase the optical densities and could lead to false positives. This goal was obtained thanks to the association of cold plasma and wet chemistries of the inner surface of the titration well. The PP surface was cold plasma-activated, then coated with different amphiphilic molecules bearing either ionic charges and/or long hydrocarbon chains. The support treated and coated with hexatrimethylammonium bromide improves the signal detection of proteins while reducing the background due to non-specific associations of biomolecules such as hyperphosphorylated Tau protein. However, coating with 3-butenylamine hydrochloride could also be suitable.

Study of the adhesion of neurodegenerative proteins on plasma-modified and coated polypropylene surfaces.

The inner polymeric surface of an ELISA titration well is plasma-modified and coated with different surfactant molecules. The titration of neurodegenerative proteins markers (prion, Tau and ß-synuclein), previously demonstrated as more efficient with such modified tubes, is related to the adhesion behaviour of these proteins and their corresponding capture antibodies. The adhesion process is studied in terms of anchoring and specific mechanisms. The proteins and antibodies binding onto such modified surfaces is related to the substrate hydrophilic character calculated from the angle contact measure, to the polymer surface charge measured through the streaming potential determination at different pH and the inner surface roughness determined from AFM images. Furthermore, the influence of the blocking agent used during the ELISA titration is also studied.

Rapid screening and confirmatory methods for biochemical diagnosis of human prion disease.

Transmissible spongiform encephalopathies (TSEs) are characterised by accumulation of an abnormal isoform of prion protein (PrP(sc)), mainly in the brain but also in various peripheral tissues. Home-made assays consisting of non-standardised protocols are used currently for laboratory diagnosis of human TSE. The purpose of the present study was to test the ability of two commercial assays, TeSeE™ CJD ELISA and TeSeE™ Western blot, to detect PrPsc in cerebral and lymphoid tissues of TSE patients. Both tests detected a PrPsc-significant signal in the brains of 54 affected patients and not in 51 controls, yielding 100% specificity and 100% sensitivity. Furthermore, three post-mortem spleens and two pre-mortem tonsils from three patients with variant Creutzfeldt-Jakob disease (vCJD) were detected correctly. The expected PrPsc molecular patterns were found in TSE patient brain tissue and in the tonsils and spleens of the three vCJD patients. In conclusion, these rapid and robust in vitro tools were suitable for routine human TSE diagnosis and characterisation. CJD could also be diagnosed during the patient's lifetime by detection of PrPsc in the tonsil. A diagnostic strategy associating TeSeE™ CJD ELISA screening to biochemical confirmation by TeSeE™ Western blot is proposed.

CSF biomarkers in posterior cortical atrophy.

OBJECTIVE: To describe CSF biomarker profiles in posterior cortical atrophy (PCA), which induces high-order visual deficits often associated with Alzheimer disease (AD) pathology, and relate these findings to clinical and neuropsychological assessment. METHODS: This prospective observational study included 22 patients with PCA who underwent CSF biomarker analysis of total tau (t-tau), phosphorylated tau on amino acid 181 (p-tau181), and amyloid ß (Aß(42)). At group level, the CSF profiles of patients with PCA were compared to those of patients with typical AD and patients with other dementia (OD). Individually, the clinical presentation of patients with PCA was correlated to their CSF profile to assess the predictability of clinical features for diagnosis of underlying AD pathology. RESULTS: At group level, the PCA biomarker profile was not different from that of the AD group, but very different from that of the OD group (p < 0.001). More than 90% of patients with PCA had CSF profiles consistent with AD. All patients with PCA with either isolated higher-order visual deficit (n = 8) or visual deficit associated with memory impairment (n = 11) had CSF profiles consistent with AD. Only one of the 3 patients with PCA with asymmetric motor signs fulfilled biological CSF criteria for AD. CONCLUSIONS: PCA syndrome is usually associated with CSF biomarkers suggestive of AD, as shown by previous neuropathologic studies. This does not apply in case of motor signs suggesting associated corticobasal syndrome. CSF biomarkers help to discriminate AD from non-AD processes associated with this condition.

[Contribution of CSF analysis to diagnosis and follow-up of tuberculous meningitis]. / Contribution de l'analyse du LCR au diagnostic et au suivi évolutif d'une méningite tuberculeuse.

We report the case of a patient who was admitted to the hospital because of language and mental confusion. His initial lumbar puncture revealed 193 leukocytes per mm3 mostly lymphocytes (95%), no red blood cells, high protein content (1.20 g/L) and normal glucose level. The antibiotic therapy by amoxicilline and aciclovir during 6 days led to complete clinical recovery in a week. A CT scan of the cerebrum showed no abnormalities, nor did chest radiography. Twelve days after discharge, the patient was rehospitalized because of a meningitis syndrome. On lumbar puncture, the CSF analysis revealed 280 leukocytes/mm3, 56% lymphocytes, 10% monocytes and 34% polymorphonuclear cells. CSF chemistry showed a protein level of 3.54 g/L, and a glucose level depressed at 0.9 mmol/L. Because of the clinical symptoms and CSF abnormalities, the patient received aciclovir, amoxicilline vancomycine, isoniazide, rifampicine, pyrazinamide and ethambutol. Screening for infections gave negative results until the 37th day, when the diagnosis of tuberculous meningitis was confirmed by the isolation of Mycobacterium tuberculosis in the repetitive CSF. Antituberculous therapy was expanded. According the Reiber diagrams, intrathecal IgG synthesis was negative at day 25, day 37, month 4, month 9, month 17. Intrathecal IgM synthesis was elevated at day 12 and day 25 and intrathecal IgA synthesis at day 25. Improvement of the patient's conditions by tuberculosis treatment was obtained in 17 months. Cerebrospinal fluid analysis has been the basis for the diagnosis and follow-up of tuberculous meningitidis.

Inactivation of animal and human prions by hydrogen peroxide gas plasma sterilization.

Prions cause various transmissible spongiform encephalopathies. They are highly resistant to the chemical and physical decontamination and sterilization procedures routinely used in healthcare facilities. The decontamination procedures recommended for the inactivation of prions are often incompatible with the materials used in medical devices. In this study, we evaluated the use of low-temperature hydrogen peroxide gas plasma sterilization systems and other instrument-processing procedures for inactivating human and animal prions. We provide new data concerning the efficacy of hydrogen peroxide against prions from in vitro or in vivo tests, focusing on the following: the efficiency of hydrogen peroxide sterilization and possible interactions with enzymatic or alkaline detergents, differences in the efficiency of this treatment against different prion strains, and the influence of contaminating lipids. We found that gaseous hydrogen peroxide decreased the infectivity of prions and/or the level of the protease-resistant form of the prion protein on different surface materials. However, the efficiency of this treatment depended strongly on the concentration of hydrogen peroxide and the delivery system used in medical devices, because these effects were more pronounced for the new generation of Sterrad technology. The Sterrad NX sterilizer is 100% efficient (0% transmission and no protease-resistant form of the prion protein signal detected on the surface of the material for the mouse-adapted bovine spongiform encephalopathy 6PB1 strain and a variant Creutzfeldt-Jakob disease strain). Thus, gaseous or vaporized hydrogen peroxide efficiently inactivates prions on the surfaces of medical devices.