Increased levels of neurotrophins in the cerebrospinal fluid of children with Epstein-Barr virus meningoencephalitis

Blood and CSF levels of brain-derived neurotrophic factor in patients with encephalopathy/encephalitis: a systematic review and meta-analysis

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is critical for enhancing the survival and growth of neurons and modulating the synaptic plasticity. BDNF levels have been demonstrated to be changed in plasma and cerebrospinal fluid (CSF) following brain insults such as inflammation or ischemia or infection in several studies. Currently, there is no systematic review regarding BDNF levels in encephalitis or encephalopathy patients. Considering inconsistency between studies, we aimed to pool the data from existing studies to determine whether blood or CSF levels of BDNF are different in patients with encephalopathy/encephalitis.

METHODS

We comprehensively searched Web of Science, PubMed, Scopus, and Embase databases to identify eligible studies. The last search occurred in December 2022.

RESULTS

12 studies met our inclusion criteria and ten studies including 283 patients and 323 healthy controls were enrolled in this meta-analysis. In comparison to controls, patients with encephalitis/encephalopathy had higher levels of BDNF in their CSF [standardized mean difference (SMD) = 1.48, 95% CI 0.18-2.77; P = 0.03)], while their blood levels of BDNF did not differ significantly [standardized mean difference (SMD) = 0.27, 95% CI = - 0.71 to 1.25; P = 0.58)]. Moreover, regarding the heterogeneity among studies reporting BDNF blood levels, we performed two subgroup analyses based on the disease etiology and the specimen (plasma and serum); none of them indicated statistically significant difference in BDNF levels between the subgroups (P = 0.41 and 0.20, respectively).

CONCLUSION

Meta-analysis provides evidence that patients with encephalopathy/encephalitis have higher CSF levels of BDNF compared to controls.

Elevated brain derived neurotrophic factor in plasma and interleukin-6 levels in cerebrospinal fluid in meningitis compared to cerebral malaria

Neurological infections, such as Cerebral malaria (CM) and meningitis are associated with high mortality and in survivors, particularly young children, persistent neurologic deficits often remain. As brain inflammation plays a role in the development of these neurological sequelae, multiplex assays were used to assess a select set of immune mediators in both plasma and cerebrospinal fluid (CSF) from Zambian children with neurological infections. Both CM and meningitis patients showed high levels of markers for vascular inflammation, such as soluble ICAM-1 and angiopoietins. Although high levels of angiopoietin 1 and angiopoietin 2 were found in the meningitis group, their levels in the CSF were low and did not differ. As expected, there were high levels of cytokines and notably a significantly elevated IL-6 level in the CSF of the meningitis group. Interestingly, although elevated levels BDNF were found, BDNF levels were significantly higher in plasma of the meningitis group but similar in the CSF. The striking differences in plasma BDNF and IL-6 levels in the CSF point to markedly different neuro-pathological processes. Therefore, further investigations in the role of both IL-6 and BDNF in the neurological outcomes are needed.

EBV infection mediated BDNF expression is associated with bladder inflammation in interstitial cystitis/bladder pain syndrome with Hunner's lesion

Interstitial cystitis/bladder pain syndrome with Hunner's lesion (HIC) is characterized by chronic inflammation and nerve hyperplasia; however, the pathogenesis of HIC remains a mystery. In this study, we detected both Epstein-Barr virus (EBV) latency infection genes EBNA-1 and LMP-1 and EBV lytic infection BZLF-1 and BRLF-1 expression in the HIC bladders, indicating the coexistence of EBV persistence and reactivation in the B cells in HIC bladders. Upregulation of EBV-associated inflammatory genes in HIC bladders, such as TNF-α and IL-6, suggests EBV infection is implicated in the pathogenesis of bladder inflammation. Nerve hyperplasia and upregulation of brain-derived neurotrophic factor (BDNF) were noted in the HIC bladders. Double immunochemical staining and flow cytometry revealed the origin of BDNF to be EBV-infected B cells. Inducible BDNF expression was noted in B cells upon EBV infection, but not in the T cells. A chromatin immunoprecipitation study revealed BDNF transcription could be promoted by cooperation between EBV nuclear antigens, chromatin modifiers, and B-cell-specific transcription. Knockdown of BDNF in EBV-infected B cells resulted in the inhibition of cell proliferation and viability. Downregulation of phosphorylated SMAD2 and STAT3 after BDNF knockdown may play a role in the mechanism. Implantation of latent EBV-infected B cells into rat bladder walls resulted in a higher expression level of CD45 and PGP9.5, suggesting tissue inflammation and nerve hyperplasia. In contrast, implantation of BDNF depleted EBV-infected B cells abrogated these effects. This is the first study to provide insights into the mechanisms underlying the involvement of EBV-infected B cells in HIC pathogenesis. © 2022 The Pathological Society of Great Britain and Ireland.

Epstein-Barr Virus Detection in the Central Nervous System of HIV-Infected Patients

Simply detecting Epstein-Barr virus deoxyribonucleic acid (EBV-DNA) is insufficient to diagnose EBV-associated diseases. The current literature around EBV-DNA detection from cerebrospinal fluid (CSF) in human immunodeficiency virus (HIV)-positive non-lymphoma patients was systematically reviewed and a meta-analysis reporting the estimated pooled prevalence in this population when PCR methods are employed, targeting different sequence segments within the EBV genome, was conducted. Using a combination of three key concepts-Epstein-Barr virus detection, central nervous system disease, and human cerebrospinal fluid-and their MeSH terms, the PubMed database was searched. A total of 273 papers reporting the detection of EBV in CNS were screened, of which 13 met the inclusion criteria. The meta-analysis revealed a pooled prevalence of EBV-DNA in CSF of 20% (CI: 12-31%). The highest pooled prevalence was from studies conducted on the African population at 39% (CI: 27-51%). The investigation of the presence of EBV-DNA in the CSF was also very varied, with several gene targets used. While most patients from the articles included in this review and meta-analysis were symptomatic of CNS disorders, the pathogenicity of EBV in non-lymphoma HIV patients when detected in CSF has still not been determined. The presence of EBV-DNA in the CNS remains a concern, and further research is warranted to understand its significance in causing CNS disorders.

Unraveling the links between neurodegeneration and Epstein-Barr virus-mediated cell cycle dysregulation

The Epstein-Barr virus is a well-known cell cycle modulator. To establish successful infection in the host, EBV alters the cell cycle at multiple steps via antigens such as EBNAs, LMPs, and certain other EBV-encoded transcripts. Interestingly, several recent studies have indicated the possibility of EBV's neurotrophic potential. However, the effects and outcomes of EBV infection in the CNS are under-explored. Additionally, more and more epidemiological evidence implicates the cell-cycle dysregulation in neurodegeneration. Numerous hypotheses which describe the triggers that force post-mitotic neurons to re-enter the cell cycle are prevalent. Apart from the known genetic and epigenetic factors responsible, several reports have shown the association of microbial infections with neurodegenerative pathology. Although, studies implicating the herpesvirus family members in neurodegeneration exist, the involvement of Epstein-Barr virus (EBV), in particular, is under-evaluated. Interestingly, a few clinical studies have reported patients of AD or PD to be seropositive for EBV. Based on the findings mentioned above, in this review, we propose that EBV infection in neurons could drive it towards neurodegeneration through dysregulation of cell-cycle events and induction of apoptosis.

Biochemical Assessments of Neurotrophin-3 and Zinc Involvement in the Pathophysiology of Pediatric Febrile Seizures : Biochemical Markers in Febrile Seizures

Febrile seizures (FSs) are a common occurrence in young children and a serious concern in pediatric practice; nevertheless, the causes and mechanisms of FS are still unknown. We hypothesized a relation of neuropeptides such as neurotrophin-3 (NT-3) and growth-associated protein-43 (GAP-43) as well as zinc and the oxidant/antioxidant system with pediatric FS. The study included 100 infants categorized into 50 infants with FS and 50 febrile infants without seizures as controls. Clinical assessments, biochemical assays of NT-3 and GAP-43 using ELISA assay kits, and colorimetric measurements of TAC and Zn were performed to all participants. Overall, significant rises of the values of NT-3 and insignificant increases of GAP-43 were detected in children with FS. At the same time, zinc values and the total antioxidant capacity in serum samples were found to be decreased significantly. In addition, a negative correlation was estimated between NT-3 and zinc levels. Serum NT-3 in diagnosing febrile seizures at cutoff point > 49.62 ng/L showed 100% sensitivity, 46% specificity, positive predictive value (PPV) = 48.1%, and negative predictive value (NPP) = 100% with AUC = 0.678. Significant altered circulating NT-3 and zinc levels in FS may indicate their possible role in the pathogenesis of FS. This may open a way for further research and warrants enlightening of the pathophysiological details of FS.

Neurotrophin Signaling Impairment by Viral Infections in the Central Nervous System

Neurotrophins, such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin 3 (NT-3), NT-4, and NT-5, are proteins involved in several important functions of the central nervous system. The activation of the signaling pathways of these neurotrophins, or even by their immature form, pro-neurotrophins, starts with their recognition by cellular receptors, such as tropomyosin receptor kinase (Trk) and 75 kD NT receptors (p75NTR). The Trk receptor is considered to have a high affinity for attachment to specific neurotrophins, while the p75NTR receptor has less affinity for attachment with neurotrophins. The correct functioning of these signaling pathways contributes to proper brain development, neuronal survival, and synaptic plasticity. Unbalanced levels of neurotrophins and pro-neurotrophins have been associated with neurological disorders, illustrating the importance of these molecules in the central nervous system. Furthermore, reports have indicated that viruses can alter the normal levels of neurotrophins by interfering with their signaling pathways. This work discusses the importance of neurotrophins in the central nervous system, their signaling pathways, and how viruses can affect them.

Olfactory Stem Cells for the Treatment of Spinal Cord Injury - a new pathway to the cure?

OBJECTIVE

Since full functional recovery after spinal cord injuries (SCI) remains a major challenge, stem cell therapies represent promising strategies to improve neurological functions after SCI. The olfactory mucosa (OM) displays an attractive source of multipotent cells for regenerative approaches and is easily accessible by biopsies due to its exposed location. The regenerative capacity of the resident olfactory stem cells (OSC) has been demonstrated in animal as well as clinical studies. This study aims to demonstrate the feasibility of isolation, purification and cultivation of OSC.

METHODS

OM specimens were taken dorso-posterior from nasal middle turbinate. OSC were isolated and purified using the neurosphere assay. Differentiation capacity of the OSC in neural lineage and their behavior in a plasma clot matrix were investigated.

RESULTS

Our study demonstrated that OSC differentiated into neural lineage and were positive for GFAP as well as β-III tubulin. Furthermore, OSC were viable and proliferated in a plasma clot matrix.

CONCLUSION

Since there are no standard methods for purification, characterization, and delivery of OSC to the injury site, which is a prerequisite for the clinical approval, this study focuses on the establishment of appropriate methods and underlies the high potential of the OM for autologous cell therapeutical approaches.

Epstein-Barr Virus and Neurological Diseases

Epstein-Barr virus (EBV), also known as human herpesvirus 4, is a double-stranded DNA virus that is ubiquitous in 90–95% of the population as a gamma herpesvirus. It exists in two main states, latent infection and lytic replication, each encoding viral proteins with different functions. Human B-lymphocytes and epithelial cells are EBV-susceptible host cells. EBV latently infects B cells and nasopharyngeal epithelial cells throughout life in most immunologically active individuals. EBV-infected cells, free viruses, their gene products, and abnormally elevated EBV titers are observed in the cerebrospinal fluid. Studies have shown that EBV can infect neurons directly or indirectly via infected B-lymphocytes, induce neuroinflammation and demyelination, promote the proliferation, degeneration, and necrosis of glial cells, promote proliferative disorders of B- and T-lymphocytes, and contribute to the occurrence and development of nervous system diseases, such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, acute cerebellar ataxia, meningitis, acute disseminated encephalomyelitis, and brain tumors. However, the specific underlying molecular mechanisms are unclear. In this paper, we review the mechanisms underlying the role of EBV in the development of central nervous system diseases, which could bebeneficial in providing new research ideas and potential clinical therapeutic targets for neurological diseases.

Toward the Existence of a Sympathetic Neuroplasticity Adaptive Mechanism Influencing the Immune Response. A Hypothetical View-Part I

The nervous system exerts a profound influence on the function of the immune system (IS), mainly through the sympathetic arm of the autonomic nervous system. In fact, the sympathetic nervous system richly innervates secondary lymphoid organs (SLOs) such as the spleen and lymph nodes. For decades, different research groups working in the field have consistently reported changes in the sympathetic innervation of the SLOs during the activation of the IS, which are characterized by a decreased noradrenergic activity and retraction of these fibers. Most of these groups interpreted these changes as a pathological phenomenon, referred to as "damage" or "injury" of the noradrenergic fibers. Some of them postulated that this "injury" was probably due to toxic effects of released endogenous mediators. Others, working on animal models of chronic stimulation of the IS, linked it to the very chronic nature of processes. Unlike these views, this first part of the present work reviews evidence which supports the hypothesis of a specific adaptive mechanism of neural plasticity from sympathetic fibers innervating SLOs, encompassing structural and functional changes of noradrenergic nerves. This plasticity mechanism would involve segmental retraction and degeneration of these fibers during the activation of the IS with subsequent regeneration once the steady state is recovered. The candidate molecules likely to mediate this phenomenon are also here introduced. The second part will extend this view as to the potential changes in sympathetic innervation likely to occur in inflamed non-lymphoid peripheral tissues and its possible immunological implications.

Effects of Tumor Necrosis Factor α (TNF-α) and Interleukina 10 (IL-10) on Intercellular Cell Adhesion Molecule-1 (ICAM-1) and Cluster of Differentiation 31 (CD31) in Human Coronary Artery Endothelial Cells

BACKGROUND The aim of this study was to investigate the effects of TNF-α and IL-10 on the expression of ICAM-1 and CD31 in human coronary artery endothelial cells (HCAEC). MATERIAL AND METHODS HCAEC was treated with 0, 2.5 μg/l, 5 μg/l, and 10 μg/l of TNF-α for 2 h, 6 h, and 10 h, and with 0 μg/l, 10 μg/l, 100 μg/l, and 200 μg/l of IL-10 for 5 h, 10 h and 15 h, respectively. RNA inference of TNF-αR was performed with siRNA. Real-time PCR, Western blot analysis, and ELSA were used to detect the mRNA level and protein level of ICAM-1 and CD31. RESULTS TNF-α significantly increased the mRNA and protein expression of ICAM-1 (P<0.05), and 2.5 μg/l TNF-α had the most obvious effect. RNAi of TNF-aR reduced the induction of TNF-α on the mRNA and protein expression of ICAM-1 (P<0.05). TNF-α significantly decreased the CD31 in the supernatant (P<0.05), and 2.5 μg/l TNF-a had the most obvious effect. IL-10 significantly decreased the ICAM-1 protein level. IL-10 decreased the mRNA expression and the protein expression of CD31. The effect on mRNA was not significant (P>0.05), while the effect on the protein expression was significant (P<0.05). CONCLUSIONS TNF-α and IL-10 treatment can affect the expression of ICAM-1 and CD31 in HCAEC.