Assessment of the tau protein concentration in patients with tick-borne encephalitis

Tick-borne encephalitis virus transmitted singly and in duo with Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum bacteria by ticks as pathogens modifying lipid metabolism in human blood

BACKGROUND

Ticks are vectors of various pathogens, including tick-borne encephalitis virus causing TBE and bacteria such as Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum causing e.g. viral-bacterial co-infections (TBE + LB/HGA), which pose diagnostic and therapeutic problems. Since these infections are usually accompanied by inflammation and oxidative stress causing metabolic modifications, including phospholipids, the aim of the study was to assess the level of polyunsaturated fatty acids and their metabolism (ROS- and enzyme-dependent) products in the blood plasma of patients with TBE and TBE + LB/HGA before and after pharmacotherapy.

METHODS

The total antioxidant status was determined using 2,20-azino-bis-3-ethylbenzothiazolin-6-sulfonic acid. The phospholipid and free fatty acids were analysed by gas chromatography. Lipid peroxidation was estimated by measuring small molecular weight reactive aldehyde, malondialdehyde and neuroprostanes. The reactive aldehyde was determined using gas chromatography coupled with mass spectrometry. The activity of enzymes was examined spectrophotometrically. An analysis of endocannabinoids and eicosanoids was performed using a Shimadzu UPLC system coupled with an electrospray ionization source to a Shimadzu 8060 Triple Quadrupole system. Receptor expression was measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The reduced antioxidant status as a result of infection was accompanied by a decrease in the level of phospholipid arachidonic acid (AA) and docosahexaenoic acid (DHA) in TBE, an increase in DHA in co-infection and in free DHA in TBE with an increase in the level of lipid peroxidation products. The enhanced activity of enzymes metabolizing phospholipids and free PUFAs increased the level of endocannabinoids and eicosanoids, while decreased 15-PGJ2 and PGE2 was accompanied by activation of granulocyte receptors before pharmacotherapy and only tending to normalize after treatment.

CONCLUSION

Since classical pharmacotherapy does not prevent disorders of phospholipid metabolism, the need to support treatment with antioxidants may be suggested.

Serum and cerebrospinal fluid brain damage markers neurofilament light and glial fibrillary acidic protein correlate with tick-borne encephalitis disease severity-a multicentre study on Lithuanian and Swedish patients

BACKGROUND AND PURPOSE

Our aim was to examine the correlation between biomarkers of neuronal and glial cell damage and severity of disease in patients with tick-borne encephalitis.

METHODS

One hundred and fifteen patients with tick-borne encephalitis diagnosed in Lithuania and Sweden were prospectively included, and cerebrospinal fluid (CSF) and serum samples were obtained shortly after hospitalization. Using pre-defined criteria, cases were classified as mild, moderate or severe tick-borne encephalitis. Additionally, the presence of spinal nerve paralysis (myelitis) and/or cranial nerve affection were noted. Concentrations of the brain cell biomarkers glial fibrillary acidic protein (GFAP), YKL-40, S100B, neurogranin, neurofilament light (NfL) and tau were analysed in CSF and, in addition, NfL, GFAP and S100B levels were measured in serum. The Jonckheere-Terpstra test was used for group comparisons of continuous variables and Spearman's partial correlation test was used to adjust for age.

RESULTS

Cerebrospinal fluid and serum concentrations of GFAP and NfL correlated with disease severity, independent of age, and with the presence of nerve paralysis. The markers neurogranin, YKL-40, tau and S100B in CSF and S100B in serum were detected, but their concentrations did not correlate with disease severity.

CONCLUSIONS

Neuronal cell damage and astroglial cell activation with increased NfL and GFAP in CSF and serum were associated with a more severe disease, independent of age. Increased GFAP and NfL concentrations in CSF and NfL in serum were also indicative of spinal and/or cranial nerve damage. NfL and GFAP are promising prognostic biomarkers in tick-borne encephalitis, and future studies should focus on determining the association between these biomarkers and long-term sequelae.

Redox Imbalance and Its Metabolic Consequences in Tick-Borne Diseases

One of the growing global health problems are vector-borne diseases, including tick-borne diseases. The most common tick-borne diseases include Lyme disease, tick-borne encephalitis, human granulocytic anaplasmosis, and babesiosis. Taking into account the metabolic effects in the patient's body, tick-borne diseases are a significant problem from an epidemiological and clinical point of view. Inflammation and oxidative stress are key elements in the pathogenesis of infectious diseases, including tick-borne diseases. In consequence, this leads to oxidative modifications of the structure and function of phospholipids and proteins and results in qualitative and quantitative changes at the level of lipid mediators arising in both reactive oxygen species (ROS) and ROS enzyme-dependent reactions. These types of metabolic modifications affect the functioning of the cells and the host organism. Therefore, links between the severity of the disease state and redox imbalance and the level of phospholipid metabolites are being searched, hoping to find unambiguous diagnostic biomarkers. Assessment of molecular effects of oxidative stress may also enable the monitoring of the disease process and treatment efficacy.

Amyloid and Tau Protein Concentrations in Children with Meningitis and Encephalitis

Alzheimer’s disease (AD) has emerged as a growing threat to human health. It is a multifactorial disorder, in which abnormal amyloid beta metabolism and neuroinflammation have been demonstrated to play a key role. Intrathecal inflammation can be triggered by infections and precede brain damage for years. We analyzed the influence of infections of the central nervous system on biomarkers that are crucially involved in AD pathology. Analyses of the cerebrospinal fluid (CSF) levels of Aβ_1–42, Aβ_1–40, Tau, and pTau proteins were performed in 53 children with neuroinfections of viral (n = 26) and bacterial origin (n = 19), and in controls (n = 8). We found no changes in CSF amyloid Aβ_1–42 concentrations, regardless of etiology. We showed an increase in tau and phosphorylated tau concentrations in purulent CNS infections of the brain, compared to other etiologies. Moreover, the total concentrations of tau in the CSF correlated with the CSF absolute number of neutrophils. These findings and the Aβ 42/40 concentration quotient discrepancies in CFS between meningitis and encephalitis suggest that infections may affect the metabolism of AD biomarkers.

Assessment of the YKL-40 concentration in patients with tick-borne encephalitis

Tick-borne encephalitis (TBE) is a viral infection of the central nervous system (CNS) caused by tick-borne encephalitis virus (TBEV). It might take several clinical courses such as: meningitis, meningoencephalitis or meningoencephalomyelitis. The aim this study was to compare the YKL-40 concentration in cerebrospinal fluid (CSF) of patients with different clinical presentations of TBE and patients with excluded meningitis (control group). The concentration of YKL-40 in CSF was determined using Fujirebio tests (Ghent, Belgium) in 32 patients with TBE: Group I-patients with meningoencephalitis (n = 16); Group II-patients with meningitis (n = 16). The control group (CG) consisted of 17 patients in whom any inflammatory process in central nervous system was excluded. The concentration of YKL-40 was significantly higher in encephalitis group than in the CG after 7 days from the last dose of treatment. The concentration in patients with neuroinflammation had a significantly different concentration of YKL-40 compared to patients from the neuroinflammation control group. The ROC curve analysis indicates that CSF YKL-40 concentration at cut-off 783.87 differentiated TBE patients from CG with 100% specificity and 70% sensitivity and CSF YKL-40 concentration at cut-off 980.11 differentiated meningitis from meningoencephalitis with 87.5% specificity and 62.5% sensitivity. YKL-40 takes part in TBE pathogenesis, its concentration is the highest at the early stage of CNS involvement and decreases in the convalescent period. As YKL-40 was significantly higher in the meningitis than in the meningoencephalitis group, it might be used as biomarker in differentiation of these clinical forms of TBE.

Selected Biomarkers of Tick-Borne Encephalitis: A Review

Tick-borne encephalitis (TBE) is an acute disease caused by the tick-borne encephalitis virus. Due to the viral nature of the condition, there is no effective causal treatment for full-blown disease. Current and nonspecific TBE treatments only relieve symptoms. Unfortunately, the first phase of TBE is characterized by flu-like symptoms, making diagnosis difficult during this period. The second phase is referred to as the neurological phase as it involves structures in the central nervous system-most commonly the meninges and, in more severe cases, the brain and the spinal cord. Therefore, it is important that early markers of TBE that will guide clinical decision-making and the choice of treatment are established. In this review, we performed an extensive search of literature reports relevant to biomarkers associated with TBE using the MEDLINE/PubMed database. We observed that apart from routinely determined specific immunoglobulins, free light chains may also be useful in the evaluation of intrathecal synthesis in the central nervous system (CNS) during TBEV infection. Moreover, selected metalloproteinases, chemokines, or cytokines appear to play an important role in the pathogenesis of TBE as a consequence of inflammatory reactions and recruitment of white blood cells into the CNS. Furthermore, we reported promising findings on tau protein or Toll-like receptors. It was also observed that some people may be predisposed to TBE. Therefore, to understand the role of selected tick-borne encephalitis biomarkers, we categorized these factors and discussed their potential application in the diagnosis, prognosis, monitoring, or management of TBE.

Sleep architecture, obstructive sleep apnea and functional outcomes in adults with a history of Tick-borne encephalitis

Tick-borne encephalitis (TBE) is a widespread viral infection of the central nervous system with increasing incidence in Europe and northern Asia. Post-infectious sequelae are frequent, and patients with TBE commonly experience long-term fatigue and subjective sleep disturbances. Obstructive sleep apnea (OSA) may be a contributing factor, and objective sleep studies with polysomnography (PSG) are lacking. Forty-two adults, 22 TBE patients (cases), diagnosed in Region Västra Götaland, Sweden, between 2012 and 2015, and 20 controls without a known TBE history, underwent an overnight PSG, respectively. All participants responded to questionnaires. The cases and controls were similar regarding age, sex, obesity, concomitant diseases, smoking, and alcohol habits. Despite similar PSG characteristics such as total sleep time and OSA severity indices, the TBE cases reported statistically more sleep-related functional impairment on the Functional Outcome of Sleep Questionnaire (FOSQ) compared with the controls (median scores 18.1 vs. 19.9; p<0.05). In a multivariate analysis, TBE correlated significantly with the lower FOSQ scores (unstandardized β -1.80 [%95 confidence interval -3.02 - -0.58]; p = 0.005) independent of age, sex, total sleep time and apnea-hypopnea-index. TBE cases with OSA reported the lowest scores on the FOSQ compared with the other subgroups with TBE or OSA alone, and the ones with neither TBE nor OSA. TBE is associated with impaired functional outcomes, in which concomitant OSA may worsen the subjective symptoms. Further studies are warranted to determine the effect of treatment of concomitant OSA on functional outcomes with regard to optimal rehabilitation of TBE.

Tau-protein concentrations are not elevated in cerebrospinal fluid of patients with progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML), caused by infection with John Cunningham polyoma virus (JCPyV) in immune-compromised patients, is a serious demyelinating disease of the central nervous system. This disease often leads to major neurological impairments and consecutive disability. No effective treatment for PML has been found as yet. As JCPyV-PCR of the cerebrospinal fluid (CSF) may be negative in some cases, a reliable diagnosis might prove to be difficult as well. So far, two case reports suggested CSF-tau to be a promising biomarker for PML. Our study included 10 patients with assured diagnosis of PML and varying underlying diseases. In all but one the CSF-tau concentration was normal. Our results indicate that CSF-tau is not an appropriate biomarker for PML.