Biomarkers of Cerebral Injury and Inflammation in Pediatric Tuberculous Meningitis

Efficacy and prognostic value of peripheral blood CD4+ T cells and serum IL-6 and IL-8 in tuberculous meningitis

Objective

To investigate the value of peripheral blood clusters of differentiation 4 (CD4+) T-lymphocyte (T cells) count and serum interleukin-6 (IL-6) and interleukin-8 (IL-8) in the treatment and prognosis of tuberculous meningitis (TBM).

Methods

Sixty-five patients with TBM were prospectively included in the observation group. Sixty-five patients with pulmonary TB and a group of 65 healthy individuals served as the control groups. The differences in peripheral blood CD4+ T-cell count, serum IL-6, and IL-8 levels were compared, and changes in these indices after anti-TB treatment in the observation group were analysed. The observation group was divided into effective and ineffective groups based on their response after 24 weeks of anti-TB treatment. The study also evaluated the influence of peripheral blood CD4+ T-cell count, serum IL-6, and IL-8 levels on the adverse prognosis of TBM during anti-TB treatment.

Results

Before treatment, the CD4+ T-cell count in the peripheral blood of the observation group was lower than in both the control and healthy groups, and serum IL-6 and IL-8 levels were higher than in the control group (P < 0.001). After 24 weeks of anti-TB treatment, the CD4+ T-cell count in the peripheral blood of the observation group increased, whereas the levels of IL-6 and IL-8 decreased significantly (P < 0.001). The levels of CD4+ T cells and IL-6 in the peripheral blood of patients before treatment were identified as independent factors influencing the efficacy of anti-TB treatment (odds ratio [OR] = 0.989, 95 % confidence interval [CI]: 0.980-0.997; OR = 1.010, 95 % CI: 1.003-1.017).

Conclusion

In patients with TBM, the CD4+ T-cell count in the peripheral blood is decreased, whereas serum IL-6 and IL-8 are increased. The combination of CD4+ T cells and IL-8 shows a degree of predictive value for the prognosis of anti-TB treatment.

Evaluation and clinical significance of serum neurospecific enolase in children with pneumonia: a case-control study

BACKGROUND

Neurospecific Enolase (NSE), a multifunctional protein, is present in various tissues of the body and plays an important role in many disease processes, such as infection, inflammation, tumours, injury, and immunity. In recent years, the application of NSE in respiratory diseases has become increasingly widespread and a research hotspot.

OBJECTIVE

This study aims to explore the relationship between NSE and childhood pneumonia, providing assistance for the diagnosis and assessment of pneumonia.

METHODS

Using prospective research and case-control methods, We selected 129 children with pneumonia hospitalised in Weifang People's Hospital from September 2020 to April 2022 as the case group. Among them were 67 cases of Mycoplasma pneumoniae pneumonia (MP+), 62 cases of non-Mycoplasma pneumoniae pneumonia (MP -), and 21 cases of severe pneumonia. At the same time, 136 children who underwent outpatient health examinations were selected as the control group. The levels of NSE, ESR, CRP in cases group and NSE in control group were measured separately.

RESULT

The NSE levels in the MP + group were 17.86 (14.29-22.54) ng/mL, while those in the MP- group were 17.89 (14.10-21.66) ng/mL, both of which were higher than the control group's NSE levels of 13.26(12.18,14.44) ng/mL (H = 46.92, P = 0.000). There was no statistically significant difference in NSE levels between the MP + and MP - groups (P > 0.05). The NSE level in the severe pneumonia group was 27.38 (13.95-34.06) ng/mL, higher than that in the mild pneumonia group, which was 17.68 (14.27-21.04) ng/mL, (P = 0.024). The AUC values for diagnosing pneumonia are NSE0.714, CRP0.539, and ESR0.535, with NSE having the highest diagnostic value.

CONCLUSION

Serum NSE can serve as an inflammatory indicator for paediatric pneumonia, which has important clinical guidance significance for the diagnosis, condition evaluation, and prognosis of paediatric pneumonia.

A teenage girl with altered mental status and paraparesis

A teenage girl presented with fever and altered mental status. MRI showed diffuse leptomeningeal enhancement of the brain and spine. She was diagnosed by a positive cerebrospinal fluid (CSF) culture with tuberculous (TB) meningitis and was started on anti-TB medications and corticosteroids. Her mental status improved, but she was noted to have proximal weakness of the lower extremities. In the course of tapering corticosteroids at week 11 of anti-TB therapy, she became acutely confused and febrile. MRI demonstrated interval development of tuberculomas in the brain and a mass lesion in the thoracic spine causing cord compression. Given the clinical picture was suggestive of a paradoxical reaction, the dose of corticosteroids was increased. Infliximab was added when repeat MRI revealed enlargement of the mass lesion in the spine with worsening cord compression. She was successfully tapered off of corticosteroids. Over several months, the patient's motor function recovered fully, and she returned to ambulating without assistance.

Dynamic PET Reveals Compartmentalized Brain and Lung Tissue Antibiotic Exposures

Tuberculosis (TB) remains a leading cause of death, but antibiotic treatments for tuberculous meningitis, the deadliest form of TB, are based on those developed for pulmonary TB and not optimized for brain penetration. Here, we performed first-in-human dynamic 18F-pretomanid positron emission tomography (PET) studies in eight human subjects for three-dimensional, multi-compartmental in situ visualization of antibiotic concentration-time exposures (area under the curve - AUC), demonstrating preferential brain (AUCtissue/plasma 2.25) versus lung (AUCtissue/plasma 0.97) tissue partitioning. Preferential, antibiotic-specific partitioning into brain or lung tissues of antibiotics active against MDR strains were confirmed in experimentally-infected mice and rabbits, using dynamic PET with chemically identical antibiotic radioanalogs, and postmortem mass spectrometry measurements. PET-facilitated pharmacokinetic modeling predicted human dosing necessary to attain therapeutic brain exposures in human subjects. These data were used to design optimized, pretomanid-based regimens which were evaluated at human equipotent dosing in a mouse model of TB meningitis, demonstrating excellent bactericidal activity without an increase in intracerebral inflammation or brain injury. Importantly, several antibiotic regimens demonstrated discordant activities in brain and lung tissues in the same animal, correlating with the compartmentalized tissue exposures of the component antibiotics. These data provide a mechanistic basis for the compartmentalized activities of antibiotic regimens, with important implications for the development of antimicrobial regimens for meningitis and other infections in compartments with unique antibiotic penetration.

Urinary metabolic characterization of advanced tuberculous meningitis cases in a South African paediatric population

Tuberculous meningitis (TBM) is a severe form of tuberculosis with high neuro-morbidity and mortality, especially among the paediatric population (aged ≤12 years). Little is known of the associated metabolic changes. This study aimed to identify characteristic metabolic markers that differentiate severe cases of paediatric TBM from controls, through non-invasive urine collection. Urine samples selected for this study were from two paediatric groups. Group 1: controls (n = 44): children without meningitis, no neurological symptoms and from the same geographical region as group 2. Group 2: TBM cases (n = 13): collected from paediatric patients that were admitted to Tygerberg Hospital in South Africa on the suspicion of TBM, mostly severely ill; with a later confirmation of TBM. Untargeted 1H NMR-based metabolomics data of urine were generated, followed by statistical analyses via MetaboAnalyst (v5.0), and the identification of important metabolites. Twenty nine urinary metabolites were identified as characteristic of advanced TBM and categorized in terms of six dysregulated metabolic pathways: 1) upregulated tryptophan catabolism linked to an altered vitamin B metabolism; 2) perturbation of amino acid metabolism; 3) increased energy production-metabolic burst; 4) disrupted gut microbiota metabolism; 5) ketoacidosis; 6) increased nitrogen excretion. We also provide original biological insights into this biosignature of urinary metabolites that can be used to characterize paediatric TBM patients in a South African cohort.

Factors associated with in-hospital mortality in HIV-infected children treated for tuberculous meningitis hydrocephalus

PURPOSE

The study aimed to investigate factors associated with in-hospital mortality in children diagnosed with tuberculous meningitis (TBM) hydrocephalus and HIV co-infection undergoing cerebrospinal fluid diversion procedures and their complications.

METHODS

Data were collected retrospectively and prospectively between 2007 and 2022. Data collected included demographics, clinical characteristics, antiretroviral therapy (ART) status, biochemistry results, CD4 count, radiology findings, CSF diversion procedures (and complications), length of hospital stay (LOHS), and in-hospital mortality.

RESULTS

Thirty-one children were included, with a mean age of 6.7 ± 5.3 years and 67.7% males. Median admission Glasgow Coma Scale (GCS) was 11 (IQR 9-15). Hypertonia (64.5%) and seizures (51.6%) were frequently observed clinical characteristics. Sixty-one percent of children were on ART. Cerebral infarcts and extra-meningeal TB were diagnosed in 64.5% and 19.3% of cases, respectively. The median CD4 count was 151 (IQR 70-732) cells/µL. Surgical procedures included ventriculoperitoneal shunt (VPS) in 26 cases and endoscopic third ventriculostomy (ETV) in five children. VPS complication rate was 27%. No complications were reported for ETV. Median LOHS was 7 days (IQR 4-21). Eleven children (35.5%) died during admission. Factors associated with mortality included GCS (p = 0.032), infarcts (p = 0.004), extra-meningeal TB (p = 0.003), VPS infection (p = 0.018), low CD4 count (p = 0.009), and hyponatremia (p = 0.002). No statistically significant factors were associated with VPS complications.

CONCLUSION

TBM hydrocephalus in HIV-infected children carries a high mortality. Clinicians in high-prevalence settings should have a high suspicion index and institute early treatment.

Rifampicin and protein concentrations in paired spinal versus ventricular cerebrospinal fluid samples of children with tuberculous meningitis

BACKGROUND

Tuberculous meningitis (TBM) is the most lethal form of TB. To study the disease, drug concentrations in samples obtained from the spinal CSF are usually used to reflect brain concentrations. Emerging data suggest that transport of substances across capillaries in the brain (ventricular CSF) and spinal cord may differ.

METHODS

We examined paired, time-linked samples of ventricular CSF (VCSF) and lumbar CSF (LCSF) of 28 patients with TBM and analysed these for rifampicin and total protein concentrations. Clinically indicated samples from procedures to determine the level of CSF block were collected from children being treated for TBM and hydrocephalus. Total protein concentrations were determined using the bicinchoninic acid (BCA) or turbidimetry assay, and rifampicin concentrations were determined using a validated LC coupled with tandem MS method. A paired Wilcoxon signed-rank test was used to determine significance.

RESULTS

TBM was confirmed in 19 cases (68%) using TB culture or GeneXpert Mtb/Rifampicin assay. All other cases were classified as probable. The median total protein concentration in LCSF was 6.0 g/L and in VCSF was 1.3 g/L. The median rifampicin concentration in LCSF was 299 ng/mL and 133 ng/mL in VCSF. The median ratio of LCSF/VSCF for protein was 4.23 and 1.57 for rifampicin.

CONCLUSIONS

Total protein and rifampicin concentrations differed significantly between the two compartments, both being higher in LCSF than in VCSF samples (P < 0.0001 for total protein and P = 0.0046 for rifampicin). Further studies are required to explore the causative reasons for the observed differences.

The influence of fixation and cryopreservation of cerebrospinal fluid on antigen expression and cell percentages by flow cytometric analysis

The pauci-cellular nature of cerebrospinal (CSF), particularly ventricular CSF, and the rapid cell death following sampling, incumbers the use of flow cytometric analysis of these samples in the investigation of central nervous system (CNS) pathologies. Developing a method that allows long-term storage and batched analysis of CSF samples without compromising cell integrity is highly desirable in clinical research, given that CSF is often sampled after hours creating logistical difficulties for fresh processing. We examined percentages and relative proportion of peripheral and brain-derived immune cells in cryopreserved and transfix-treated CSF, compared to freshly processed CSF. Cell proportions were more comparable between Fresh and Cryopreserved CSF (mean of differences = 3.19), than between fresh and transfix-treated CSF (mean of differences = 14.82). No significant differences in cell percentages were observed in fresh versus cryopreserved CSF; however significantly lower cell percentages were observed in transfix-treated CSF compared to Fresh CSF [(CD11b++ (p = 0.01), CD4+ (p = 0.001), CD8+ (p = 0.007), NK cells (p = 0.04), as well as CD69+ activation marker (p = 0.001)]. Furthermore, loss of marker expression of various lymphocyte sub-populations were observed in transfix-treated CSF. Cryopreservation is a feasible option for long-term storage of ventricular CSF and allows accurate immunophenotyping of peripheral and brain-derived cell populations by flow cytometry.

Evaluation of cerebrospinal fluid levels for ALOX5, S100B, DEFA1, and GFAP in infectious meningitis

BACKGROUND

The aim of this study was to determine how the levels of peptide and protein-based biomarkers in cerebrospinal fluid change in bacterial, tuberculous, and aseptic meningitis, and to determine the success of these agents in distinguishing between different types of infectious meningitis.

METHODS

The levels of arachidonate-5-lipoxygenase, S100 calcium-binding protein B, defensin-α 1, and glial fibrillary acidic protein in cerebrospinal fluid samples from 20 tuberculosis, 40 bacterial, 25 aseptic meningitis patients, and 55 control groups were measured and compared using an enzyme-linked immunosorbent assay.

RESULTS

The mean age of the patients was 37.9 ± 14.4 years. The parameter that contributed the most to the differential diagnosis of the infectious meningitis groups was S100 calcium-binding protein B. The S100 calcium-binding protein B levels were significantly higher in the tuberculous meningitis group than in the other groups, and arachidonate-5-lipoxygenase levels were significantly higher in the tuberculous meningitis and bacterial meningitis groups (P < .05).

CONCLUSION

This study showed that cerebrospinal fluid arachidonate-5-lipoxygenase, and S100 calcium-binding protein B levels may differ in bacterial, aseptic, and tuberculous meningitis, and the results obtained may be quite effective as important potential biomarkers in the differential diagnosis of different types of meningitis.

Prognostic identifier of cerebrovascular complications in tuberculous meningitis: Meta-analysis

INTRODUCTION

Cerebrovascular complications could occur in 15-57 % of patients with tuberculous meningitis (TBM). It is crucial to rapidly identify TBM patients who are at risk for stroke. This study aimed to find predictors of stroke in patients with TBM.

METHODS

This systematic review and meta-analysis were done using literature searches through online databases up to April 30th, 2022. Three independent authors performed literature screening, data extraction, and critical appraisal of the studies. Eight studies involving 1535 samples were included.

RESULTS

We analyzed data regarding demographic, comorbidity, clinical presentation, radiologic, and laboratory parameters. Overall, clinical presentation that showed outcome difference was found in patients with findings of vomiting (OR = 2.71, 95 % CI: 1.30-5.63), cranial nerve deficit (OR = 4.10, 95 % CI: 1.83-9.21), focal deficit (OR = 5.56, 95 % CI: 2.24-13.79), and altered consciousness (OR = 1.90, 95 % CI: 1.24-2.92). Some comorbidities showed significant differences such as diabetes mellitus (OR = 2.58, 95 % CI: 1.51-4.41), hypertension (OR = 5.73, 95 % CI: 3.36-9.77), ischemic heart disease (OR = 2.18, 95 % CI: 1.02-4.63), and smoking (OR = 2.65, 95 % CI: 1.22-5.77). Two radiological changes shown to have significantly higher proportions are hydrocephalus (OR = 2.50, 95 % CI: 1.74-3.58) and meningeal enhancements (OR = 3.99, 95 % CI: 1.73-9.20).

CONCLUSION

Our analysis indicated that clinical presentations of vomiting, cranial nerve deficit, focal deficit, altered consciousness; comorbidity of diabetes mellitus, hypertension, smoking history, ischemic heart disease; and radiological findings of meningeal enhancement and hydrocephalus showed significant association with stroke incidence in tuberculous meningitis.

Higher plasma interleukin - 6 levels are associated with lung cavitation in drug-resistant tuberculosis

BACKGROUND

Lung cavitation is associated with heightened TB transmission and poor treatment outcomes. This study aimed to determine the relationship between systemic inflammation and lung cavitation in drug-resistant TB patients with and without HIV co-infection.

METHODS

Plasma samples were obtained from 128 participants from the CAPRISA 020 Individualized M(X)drug-resistant TB Treatment Strategy Study (InDEX) prior to treatment initiation. Lung cavitation was present in 61 of the 128 drug-resistant TB patients with 93 being co-infected with HIV. The plasma cytokine and chemokine levels were measured using the 27-Plex Human Cytokine immunoassay. Modified Poisson regression models were used to determine the association between plasma cytokine/chemokine expression and lung cavitation in individuals with drug-resistant TB.

RESULTS

Higher Interleukin-6 plasma levels (adjusted risk ratio [aRR] 1.405, 95% confidence interval [CI] 1.079-1.829, p = 0.011) were associated with a higher risk of lung cavitation in the multivariable model adjusting for age, sex, body mass index, HIV status, smoking and previous history of TB. Smoking was associated with an increased risk of lung cavitation (aRR 1.784, 95% CI 1.167-2.729, p = 0.008). An HIV positive status and a higher body mass index, were associated with reduced risk of lung cavitation (aRR 0.537, 95% CI 0.371-0.775, p = 0.001 and aRR 0.927, 95% CI 0.874-0.983, p = 0.012 respectively).

CONCLUSION

High plasma interleukin-6 levels are associated with an increased risk of cavitary TB highlighting the role of interleukin-6 in the immunopathology of drug-resistant TB.

Gliosis, misfolded protein aggregation, and neuronal loss in a guinea pig model of pulmonary tuberculosis

Tuberculosis, caused by Mycobacterium tuberculosis infection, is an ongoing epidemic with an estimated ten million active cases of the disease worldwide. Pulmonary tuberculosis is associated with cognitive and memory deficits, and patients with this disease are at an increased risk for Parkinson's disease and dementia. Although epidemiological data correlates neurological effects with peripheral disease, the pathology in the central nervous system is unknown. In an established guinea pig model of low-dose, aerosolized Mycobacterium tuberculosis infection, we see behavior changes and memory loss in infected animals. We correlate these findings with pathological changes within brain regions related to motor, cognition, and sensation across disease progression. This includes microglial and astrocytic proliferation and reactivity. These cellular changes are followed by the aggregation of neurotoxic amyloid β and phosphorylated tau and, ultimately, neuronal degeneration in the hippocampus. Through these data, we have obtained a greater understanding of the neuropathological effects of a peripheral disease that affects millions of persons worldwide.

Population Pharmacokinetic Analysis of Rifampicin in Plasma, Cerebrospinal Fluid, and Brain Extracellular Fluid in South African Children with Tuberculous Meningitis

Limited knowledge is available on the pharmacokinetics of rifampicin in children with tuberculous meningitis (TBM) and its penetration into brain tissue, which is the site of infection. In this analysis, we characterize the distribution of rifampicin in cerebrospinal fluid (CSF), lumbar (LCSF) and ventricular (VCSF), and brain extracellular fluid (ECF). Children with TBM were included in this pharmacokinetic analysis. Sparse plasma, LCSF, and VCSF samples were collected opportunistically, as clinically indicated. Brain ECF was sampled using microdialysis (MD). Rifampicin was quantified with liquid chromatography with tandem mass spectrometry in all samples, and 25-desacetyl rifampicin in the plasma samples. The data were interpreted with nonlinear mixed-effects modeling, with the CSF and brain ECF modeled as "effect compartments." Data were available from 61 children, with median (min-max) age of 2 (0.3 to 10) years and weight of 11.0 (4.8 to 49.0) kg. A one-compartment model for parent and metabolite with first-order absorption and elimination via saturable hepatic clearance described the data well. Allometric scaling, maturation, and auto-induction of clearance were included. The pseudopartition coefficient between plasma and LCSF/VCSF was ~5%, while the value for ECF was only ~0.5%, possibly reflecting low recovery of rifampicin using MD. The equilibration half-life between plasma and LCSF/VCSF was ~4 h and between plasma and ECF ~2 h. Our study confirms previous reports showing that rifampicin concentrations in the LCSF are lower than in plasma and provides novel knowledge about rifampicin in the VCSF and the brain tissue. Despite MD being semiquantitative because the relative recovery cannot be quantified, our study presents a proof-of-concept that rifampicin reaches the brain tissue and that MD is an attractive technique to study site-of-disease pharmacokinetics in TBM.

Leukotriene A4 hydrolase (LTA4H rs17525495) gene polymorphisms and paradoxical reactions in extrapulmonary tuberculosis

Paradoxical reactions (PRs) are poorly studied complex immunological phenomena, among patients with tuberculosis (TB). When PRs involves critical structures like the central nervous system (CNS), immunomodulatory therapy is often required. Predictors for PRs in TB to pre-empt appropriate treatment strategies in high-risk groups are lacking. TT genotype of Leukotriene A4 hydrolase (LTA4H) promoter region rs17525495 polymorphisms are associated with exaggerated immune responses in Tuberculous meningitis (TBM), the most severe form of extrapulmonary tuberculosis (EPTB). The association of these polymorphisms with PRs is not known. We evaluated this plausibility among 113 patients with EPTB, at high risk of PRs. Majority [81 (71.7%)] had disseminated tuberculosis with prominent CNS [54 (47.8%)] and lymph node involvement [47 (41.6%)]. Human immunodeficiency Virus (HIV) co-infection was seen among 23 (20.3%) patients. PRs were noted in 38.9% patients, at a median duration of 3 months (IQR 2-4). LTA4H rs17525495 single nucleotide polymorphism (SNP) analysis showed 52 (46%) patients had CC, 43 (38.1%) had CT and 18 (15.9%) had TT genotypes. There was no statistically significant difference in occurrence [CC 38.5% vs CT 39.5% vs TT 38.7%] and time of onset [median (IQR)] of PRs across the genotypes [CC 3 (1-4.7), CT 3 (2-5), TT 2 (2-3)]. PRs was shown to be significantly linked with HIV co-infection (RR 0.6, 95% CI 0.29-1.28), culture positivity (RR 0.5, 95% CI 0.28-1.14), TB Lymphadenitis (RR 0.7, 95% CI 0.44-1.19) and CNS involvement RR 2.1, 95% CI 1.27-3.49) in the univariate analysis (p < 0.2). On multivariate analysis, CNS involvement alone was associated with PRs (aRR 3.8 (1.38-10.92); p < 0.01). PRs were associated with CNS involvement but not with LTA4H rs17525495 polymorphisms.

Single-cell analysis reveals changes in BCG vaccine-injected mice modeling tuberculous meningitis brain infection

Tuberculous meningitis (TBM) is the most severe and deadly manifestation of tuberculosis. Neurological complications are observed in up to 50% of patients affected. Here, attenuated Mycobacterium bovis are injected into the cerebellum of mice, and histopathological images and cultured colonies confirm successful brain infection. Then, whole-brain tissue is dissected for 10X Genomics single-cell sequencing, and we acquire 15 cell types. Transcriptional changes of inflammation processes are found in multiple cell types. Specifically, Stat1 and IRF1 are shown to mediate inflammation in macrophages and microglia. For neurons, decreased oxidative phosphorylation activity in neurons is observed, which corresponds to TBM clinical symptoms of neurodegeneration. Finally, ependymal cells present prominent transcriptional changes, and decreased FERM domain containing 4A (Frmd4a) may contribute to TBM clinical symptoms of hydrocephalus and neurodegeneration. This study shows a single-cell transcriptome of M. bovis infection in mice and improves the understanding of brain infection and neurological complications in TBM.

Inflammatory Markers Combined With Metalloproteinase-9, Neopterin, and S100B Concentrations May Indicate the Pathogenesis of Central Nervous System Diseases in Children

The identification of central nervous system inflammation etiology leads to adjusted therapy. We analyzed the potential inflammatory and neuro-axonal damage markers in children. Our target was to correlate the findings with a disease's course or a sequalae risk and assess their clinical usefulness. The study included 96 children with symptoms of central nervous system inflammation who underwent diagnostics. The research group involved 24 children with autoimmune disorders and 31 with neuroinfection. The control group included patients with both etiologies excluded. We analyzed the results of routine laboratory tests together with chosen serum (neopterin, interleukin [IL]-1β, IL-6) and CSF (metalloproteinase [MMP]-9, S100B protein) markers. In the whole cohort, CSF MMP-9 correlated with CSF cytosis and serum IL-6 and CRP. In the undivided neuroinflammatory group, CSF S100B correlated with serum IL-6 and IgM concentrations. CSF cytosis was associated with CSF MMP-9 and serum neopterin levels. Among the infective patients, IL-6 was linked with increased CSF MMP-9. We conclude that astroglial protein S100B, neopterin, and cytokine concentrations may enable predicting long-term consequences, whereas CSF MMP-9 concentration may reflect the actual central nervous system injury regardless of etiology.

Balancing between apoptosis and survival biomarkers in the patients with tuberculous meningitis

BACKGROUND

The balancing factor of apoptosis, survival, inflammatory and oxidative stress biomarkers may determine the clinico-radiological severity and death in the patients with tuberculous meningitis (TBM).

AIM

We report the relationship of death [caspase-3, malondialdehyde (MDA), tumor necrosis factor-α (TNFα), interleukin 6 (IL6)] and survival biomarkers [X-linked inhibitory apoptotic protein (XIAP), IL10, glutathione (GSH) and catalase] in TBM, and its role in determining disease severity and death.

METHODS

The diagnosis of TBM was based on clinical, MRI and cerebrospinal fluid (CSF) findings. Their clinical and MRI findings were noted. The severity of TBM was categorized as stages I to III. Serum and CSF caspase-3 and XIAP were measured by ELISA, and TNFα, IL6 and IL10 gene expression in peripheral blood mononuclear cells using RT-PCR (reverse-transcriptase polymerase chain reaction). Plasma MDA, GSH and catalase were measured by spectrophotometer.

RESULTS

There were 40 patients with TBM whose mean age was 31.6 years and 50% were females. TBM patients had higher expression of death (caspase-3, TNFα, IL6, and MDA) and suppression of survival biomarkers (XIAP, catalase and GSH) compared to the healthy controls. Caspase-3 positively correlated with TNFα, IL6 and MDA, and negatively with XIAP, GSH and catalase. Patients with longer duration of illness and definite TBM had higher expression of caspase-3. Patients who died has higher expression of caspase-3 and suppression of XIAP compared to those who survived.

CONCLUSION

It can be concluded from this study that there is up-regulation of death signals and suppression of survival signals in TBM.

Biomarkers of Tuberculous Meningitis and Pediatric Human Immunodeficiency Virus on the African Continent

Biomarkers in body fluids are helpful objective tools in diagnosis, prognosis and monitoring of (therapeutic) responses of many neurological diseases. Cerebrospinal fluid (CSF) biomarkers are part of the diagnostic toolbox for infectious neurological diseases. Tuberculous meningitis (TBM) and Human immunodeficiency virus (HIV), are important burdens of disease in Africa and can negatively affect brain health. Two thirds of the world's population of people living with HIV reside in sub-Saharan Africa and 25% of the global burden of tuberculosis (TB) is carried by the African continent. Neuroinflammation and damage of specific neuronal cell types are key constituents in the pathophysiology of these central nervous system (CNS) diseases, and important potential sources of circulating biomarkers. In this review, we summarize current research in the use of biomarkers in TBM and pediatric HIV as case demonstrations for high prevalence neurological diseases in Africa. Inflammatory molecules, primarily when detected in CSF, appear to have diagnostic value in these diseases, especially when measured as profiles. Brain injury molecules, such as S100, Neuron specific enolase and glial fibrillary acidic protein may have prognostic value in TBM, but more studies are needed. There is a need for more cost-economic and high sensitivity technologies to drive further biomarker discoveries and translate into healthcare improvements for these important healthcare problems in a globally fair way.

Tuberculous meningitis: progress and remaining questions

Tuberculous meningitis is a devastating brain infection that is caused by Mycobacterium tuberculosis and is notoriously difficult to diagnose and treat. New technologies characterising the transcriptome, proteome, and metabolome have identified new molecules and pathways associated with tuberculous meningitis severity and poor outcomes that could offer novel diagnostic and therapeutic targets. The next-generation GeneXpert MTB/RIF Ultra assay, when used on CSF, offers diagnostic sensitivity for tuberculous meningitis of approximately 70%, although it is not widely available and a negative result cannot rule out tuberculous meningitis. Small trials indicate that clinical outcomes might be improved with increased doses of rifampicin, the addition of linezolid or fluoroquinolones to standard antituberculosis therapy, or treatment with adjunctive aspirin combined with corticosteroids. Large phase 3 clinical trials are underway worldwide to address these and other questions concerning the optimal management of tuberculous meningitis; these studies also form a platform for studying pathogenesis and identifying novel diagnostic and treatment strategies, by allowing the implementation of new genomic, transcriptomic, proteomic, and metabolomic technologies in nested substudies.

Central Inflammatory Cytokines in Tuberculous Meningitis: A Systematic Review and Meta-analysis

No formal agreement exists regarding central inflammatory cytokine aberrations in tuberculosis (TB). We undertook a systematic review and meta-analysis of studies comparing cytokine levels in cerebrospinal fluid (CSF) from patients with TB compared with controls. We searched PubMed, Scopus, and Web of Science for articles published up to June 22, 2021. Studies were included in the meta-analysis if they assessed unadjusted levels of cytokines in unstimulated CSF samples and drew the comparison(s) between any of the following pairs: patients with TB versus controls without central nervous system (CNS) infection and meningitis, patients with TB versus patients with meningitis of etiologies other than Mycobacterium tuberculosis, HIV-infected patients with TB versus HIV-uninfected patients with TB, and HIV-infected patients with TB versus HIV-infected patients without TB. The primary outcome was the difference in mean CSF inflammatory cytokine levels between each of the 2 groups mentioned. The standardized mean difference was chosen to measure effect using a restricted maximum-likelihood estimator random-effects model. Of 1170 records identified, 40 studies were included in the meta-analysis. We calculated effect sizes for 30 different cytokines. About half of the studies took place in South Africa and India (18 out of 40 studies). Studies were mostly (92.5%) on patients with tuberculous meningitis (TBM), with only 3 articles of patients with neurotuberculosis and spinal TB. The quality of studies was rated as low to moderate and high with a 1.2:1 ratio. Compared with controls without CNS infection and meningitis, interferon-gamma (IFNγ), interleukin (IL)-12p40, IL-17F, IL-1β, IL-2, IL-4, IL-6, IL-8, sIL-2R, transforming growth factor beta (TGFβ), TGFβ1, and tumor necrosis factor alpha (TNFα) were increased in patients with TBM. Compared with patients with meningitis of etiologies other than M. tuberculosis or combined meningitis and nonmeningitis patients, patients with TBM had higher CSF concentrations of IFNγ, IL-13, and sIL-2R, whereas levels of IL-12p70, IL-15, IL-1Ra, IL-5, IL-7, IL-9, and sTNFR55 were decreased. Compared with patients with meningitis of bacterial etiologies other than M. tuberculosis, CSF levels of IFNγ and sIL-2R were increased in patients with TBM, whereas levels of IL-1Ra, IL-13, IL-17, and TNF R55-BP were decreased. Patients with TBM were not different from patients with CM for most CSF cytokines assessed, but IFNγ and IL-1β were increased. TNFα, IL-1β, IL-1Ra, IL-8, IFNγ, sIL-2R, IL-13, and IL-17 were higher in patients with TBM than those with viral or aseptic meningitis. Compared with HIV-negative patients with TBM, IFNγ, IL-10, IL-12p70, and IL-5 were decreased in HIV-positive patients with TBM, whereas IL-1β, TNFα, and IL-2 were increased. Elevated TNFα, IL-1β, IFNγ, IL-6, IL-17, and IFNα2 were found in HIV-positive patients with TBM compared with their counterparts without TBM. This study should be considered an explorative meta-analytic review, leading us to offer the best TBM-associated central inflammatory cytokines. Our study could prepare a panel of central cytokines as a potential aid in diagnosing TBM and its differentiation from meningitis of other etiologies.

Neutrophil-Mediated Immunopathology and Matrix Metalloproteinases in Central Nervous System - Tuberculosis

Tuberculosis (TB) remains one of the leading infectious killers in the world, infecting approximately a quarter of the world’s population with the causative organism Mycobacterium tuberculosis (M. tb). Central nervous system tuberculosis (CNS-TB) is the most severe form of TB, with high mortality and residual neurological sequelae even with effective TB treatment. In CNS-TB, recruited neutrophils infiltrate into the brain to carry out its antimicrobial functions of degranulation, phagocytosis and NETosis. However, neutrophils also mediate inflammation, tissue destruction and immunopathology in the CNS. Neutrophils release key mediators including matrix metalloproteinase (MMPs) which degrade brain extracellular matrix (ECM), tumor necrosis factor (TNF)-α which may drive inflammation, reactive oxygen species (ROS) that drive cellular necrosis and neutrophil extracellular traps (NETs), interacting with platelets to form thrombi that may lead to ischemic stroke. Host-directed therapies (HDTs) targeting these key mediators are potentially exciting, but currently remain of unproven effectiveness. This article reviews the key role of neutrophils and neutrophil-derived mediators in driving CNS-TB immunopathology.

Infections in the Developing Brain: The Role of the Neuro-Immune Axis

Central nervous system (CNS) infections occur more commonly in young children than in adults and pose unique challenges in the developing brain. This review builds on the distinct vulnerabilities in children's peripheral immune system (outlined in part 1 of this review series) and focuses on how the developing brain responds once a CNS infection occurs. Although the protective blood-brain barrier (BBB) matures early, pathogens enter the CNS and initiate a localized innate immune response with release of cytokines and chemokines to recruit peripheral immune cells that contribute to the inflammatory cascade. This immune response is initiated by the resident brain cells, microglia and astrocytes, which are not only integral to fighting the infection but also have important roles during normal brain development. Additionally, cytokines and other immune mediators such as matrix metalloproteinases from neurons, glia, and endothelial cells not only play a role in BBB permeability and peripheral cell recruitment, but also in brain maturation. Consequently, these immune modulators and the activation of microglia and astrocytes during infection adversely impact normal neurodevelopment. Perturbations to normal brain development manifest as neurodevelopmental and neurocognitive impairments common among children who survive CNS infections and are often permanent. In part 2 of the review series, we broadly summarize the unique challenges CNS infections create in a developing brain and explore the interaction of regulators of neurodevelopment and CNS immune response as part of the neuro-immune axis.

Predictors of fever response in tuberculous meningitis: A clinical, MRI and biomarker study

BACKGROUND

Central nervous system (CNS) has a different immune surveillance system; therefore, fever at admission and timeline of fever response after antitubercular treatment (ATT) may follow a different course in CNS infection. We report the predictors of fever response in tuberculous meningitis (TBM) including the effect of tumour necrosis factor-α (TNF-α) in cerebrospinal fluid (CSF) and its gene expression at mRNA of peripheral blood mononuclear cells (PBMCs).

METHODS

Fifty-seven patients with TBM were prospectively evaluated. Their clinical findings and severity of meningitis were recorded. The expression of TNF-α gene in PBMCs was quantified by real-time polymerase chain reaction and TNF-α concentration in CSF by cytokine bead array both in the patients and 14 matched controls.

RESULTS

All the patients had history of fever for a median duration of 75 days. The admission temperature ranged between 37.2°C and 40°C and correlated with CSF cell counts (p < 0.05). Cranial MRI was abnormal in 54 (94.7%) and revealed exudates in 33(57.9%), hydrocephalus in 27(47.4%), infarction in 27(47.4%) and tuberculoma in 33(57.9%) patients. Fever subsided after a median duration of 18 (2 60) days of treatment. Twelve (21.8%) patients only became afebrile within 10 days. The expression of TNF-α gene correlated with CSF concentration of TNF-α (p = 0.02) and independently predicted duration of defervescence [adjusted hazard ratio 1.02 (95% CI 1.00-1.04; p = 0.01).

CONCLUSION

In the patients with TBM, defervescence takes longer time, and TNF-α gene expression predicts the duration of defervescence. Future studies are needed to evaluate the role of TNF-α-modifying drugs in TBM.

Tuberculous Meningitis in Children: Reducing the Burden of Death and Disability

Tuberculous meningitis disproportionately affects young children. As the most devastating form of tuberculosis, it is associated with unacceptably high rates of mortality and morbidity even if treated. Challenging to diagnose and treat, tuberculous meningitis commonly causes long-term neurodisability in those who do survive. There remains an urgent need for strengthened surveillance, improved rapid diagnostics technology, optimised anti-tuberculosis drug therapy, investigation of new host-directed therapy, and further research on long-term functional and neurodevelopmental outcomes to allow targeted intervention. This review focuses on the neglected field of paediatric tuberculous meningitis and bridges current clinical gaps with research questions to improve outcomes from this crippling disease.

Elevated CSF inflammatory markers in patients with idiopathic normal pressure hydrocephalus do not promote NKCC1 hyperactivity in rat choroid plexus

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible neurological condition of unresolved etiology characterized by a clinical triad of symptoms; gait disturbances, urinary incontinence, and cognitive deterioration. In the present study, we aimed to elucidate the molecular coupling between inflammatory markers and development of iNPH and determine whether inflammation-induced hyperactivity of the choroidal Na⁺/K⁺/2Cl^- cotransporter (NKCC1) that is involved in cerebrospinal fluid (CSF) secretion could contribute to the iNPH pathogenesis.

METHODS

Lumbar CSF samples from 20 iNPH patients (10 with clinical improvement upon CSF shunting, 10 without clinical improvement) and 20 elderly control subjects were analyzed with the novel proximity extension assay technique for presence of 92 different inflammatory markers. RNA-sequencing was employed to delineate choroidal abundance of the receptors for the inflammatory markers found elevated in the CSF from iNPH patients. The ability of the elevated inflammatory markers to modulate choroidal NKCC1 activity was determined by addition of combinations of rat version of these in ex vivo experiments on rat choroid plexus.

RESULTS

11 inflammatory markers were significantly elevated in the CSF from iNPH patients compared to elderly control subjects: CCL28, CCL23, CCL3, OPG, CXCL1, IL-18, IL-8, OSM, 4E-BP1, CXCL6, and Flt3L. One inflammatory marker, CDCP1, was significantly decreased in iNPH patients compared to control subjects. None of the inflammatory markers differed significantly when comparing iNPH patients with and without clinical improvement upon CSF shunting. All receptors for the elevated inflammatory markers were expressed in the rat and human choroid plexus, except CCR4 and CXCR1, which were absent from the rat choroid plexus. None of the elevated inflammatory markers found in the CSF from iNPH patients modulated the choroidal NKCC1 activity in ex vivo experiments on rat choroid plexus.

CONCLUSION

The CSF from iNPH patients contains elevated levels of a subset of inflammatory markers. Although the corresponding inflammatory receptors are, in general, expressed in the choroid plexus of rats and humans, their activation did not modulate the NKCC1-mediated fraction of choroidal CSF secretion ex vivo. The molecular mechanisms underlying ventriculomegaly in iNPH, and the possible connection to inflammation, therefore remains to be elucidated.

Low cerebrospinal fluid Amyloid-βeta 1-42 in patients with tuberculous meningitis

BACKGROUND

Tuberculous meningitis (TBM) is an important disease leading to morbidity, disability and mortality that primarily affects children and immune-depressed patients. Specific neuromarkers predicting outcomes, severity and inflammatory response are still lacking. In recent years an increasing number of evidences show a possible role for infective agents in developing neurodegenerative diseases.

METHODS

We retrospectively included 13 HIV-negative patients presenting with TBM and we compared them with two control groups: one of patients with a confirmed diagnosis of AD, and one of those with syphilis where lumbar punctures excluded central nervous system involvement. Lumbar punctures were performed for clinical reasons and CSF biomarkers were routinely available: we analyzed blood brain barrier permeability (CSF to serum albumin ratio, "CSAR"), intrathecal IgG synthesis, (CSF to serum IgG ratio), inflammation (neopterin), amyloid deposition (Aβ1-42), neuronal damage (T-tau, P-tau, 14.3.3) and astrocytosis (S-100 β).

RESULTS

TBM patients were 83 % male and 67 % Caucasian with a median age of 51 years (24.5-63.5 IQR). Apart from altered CSAR (median value 18.4, 17.1-30.9 IQR), neopterin (14.3 ng/ml, 9.7-18.8) and IgG ratios (15.4, 7.9-24.9), patients showed very low levels of Aβ1-42 in their CSF (348.5 pg/mL,125-532.2), even lower compared to AD and controls [603 pg/mL (IQR 528-797) and 978 (IQR 789-1178)]. Protein 14.3.3 tested altered in 38.5 % cases. T-tau, P-tau and S100Beta were in the range of normality. Altered low level of Aβ1-42 correlated over time with classical TBM findings and altered neuromarkers.

CONCLUSIONS

CSF Biomarkers from patients with TBM were compatible with inflammation, blood brain barrier damage and impairment in amyloid-beta metabolism. Amyloid-beta could be tested as a prognostic markers, backing the routine use of available neuromarkers. To our knowledge this is the first case showing such low levels of Aβ1-42 in TBM; its accumulation, drove by neuroinflammation related to infections, can be central in understanding neurodegenerative diseases.

Neuron-specific enolase serum levels in COVID-19 are related to the severity of lung injury

The multifunctional role of neuron-specific enolase (NSE) in lung diseases is well established. As the lungs are greatly affected in COVID-19, we evaluated serum NSE levels in COVID-19 patients with and without dyspnea. In this study, we evaluated both SARS-CoV-2-infected and uninfected patients aged >18 years who were referred to hospitals in Catanzaro, Italy from March 30 to July 30, 2020. Epidemiological, clinical, and radiological characteristics, treatment, and outcome data were recorded and reviewed by a trained team of physicians. In total, 323 patients (178 men, 55.1% and 145 women, 44.9%) were enrolled; of these, 128 were COVID-19 patients (39.6%) and 195 were control patients (60.4%). Westergren’s method was used to determine erythroid sedimentation rate. A chemiluminescence assay was used for measurement of interleukin-6, procalcitonin, C-reactive protein, and NSE. We detected significantly higher NSE values (P<0.05) in COVID-19 patients than in controls. Interestingly, within the COVID-19 group, we also observed a further significant increase in dyspnea (Dyspnea Scale and Exercise score: 8.2 ± 0.8; scores ranging from 0 to 10, with higher numbers indicating very severe shortness of breath). These data provide the background for further investigations into the potential role of NSE as a clinical marker of COVID-19 progression.

Serum and cerebrospinal fluid host proteins indicate stroke in children with tuberculous meningitis

Introduction

Stroke is a common complication in children with tuberculous meningitis (TBM). Host proteins may give us insight into the mechanisms of stroke in TBM and serve as biomarkers for detection of stroke, however, they have not been widely explored. In this study, we compared the concentrations of cerebrospinal fluid (CSF) and serum proteins between children who had TBM-related stroke and children with TBM without stroke.

Methods

We collected CSF and serum from 47 children consecutively admitted to the Tygerberg Academic Hospital in Cape Town, South Africa between November 2016, and November 2017, on suspicion of having TBM. A multiplex platform was used to measure the concentrations of 69 host proteins in CSF and serum from all study participants.

Results

After classification of study participants, 23 (48.9%) out of the 47 study participants were diagnosed with TBM, of which 14 (60.9%) demonstrated radiological arterial ischemic infarction. The levels of lipocalin-2, sRAGE, IP-10/ CXCL10, sVCAM-1, MMP-1, and PDGF-AA in CSF samples and the levels of D-dimer, ADAMTS13, SAA, ferritin, MCP-1/ CCL2, GDF-15 and IL-13 in serum samples were statistically different between children who had TBM-related stroke and children with TBM without stroke. After correcting for multiple testing, only the levels of sVCAM-1, MMP-1, sRAGE, and IP-10/ CXCL10 in CSF were statistically different between the two groups. CSF and serum protein biosignatures indicated stroke in children diagnosed with TBM with up to 100% sensitivity and 88.9% specificity.

Conclusion

Serum and CSF proteins may serve as biomarkers for identifying individuals with stroke amongst children diagnosed with TBM at admission and may guide us to understand the biology of stroke in TBM. This was a pilot study, and thus further investigations in larger studies are needed.

Cytokine Biosignature of Active and Latent Mycobacterium Tuberculosis Infection in Children

None of the currently used diagnostic tools are efficient enough in diagnosing Mycobacterium tuberculosis (M.tb) infection in children. The study was aimed to identify cytokine biosignatures characterizing active and latent tuberculosis (TB) in children. Using a multiplex bead-based technology, we analyzed the levels of 53 Th17-related cytokines and inflammatory mediators in sera from 216 BCG-vaccinated children diagnosed with active TB (TB) or latent TB (LTBI) as well as uninfected controls (HC). Children with active TB, compared to HC children, showed reduced serum levels of IL-17A, MMP-2, OPN, PTX-3, and markedly elevated concentrations of APRIL/TNFSF13. IL-21, sCD40L, MMP-2, and IL-8 were significantly differentially expressed in the comparisons between groups: (1) HC versus TB and LTBI (jointly), and (2) TB versus LTBI. The panel consisting of APRIL/TNFSF13, sCD30/TNFRSF8, IFN-α2, IFN-γ, IL-2, sIL-6Rα, IL-8, IL-11, IL-29/IFN-λ1, LIGHT/TNFSF14, MMP-1, MMP-2, MMP-3, osteocalcin, osteopontin, TSLP, and TWEAK/TNFSF12 possessed a discriminatory potential for the differentiation between TB and LTBI children. Serum-based host biosignatures carry the potential to aid the diagnosis of childhood M.tb infections. The proposed panels of markers allow distinguishing not only children infected with M.tb from uninfected individuals but also children with active TB from those with latent TB.

Tuberculous meningitis: where to from here?

Tuberculous meningitis (TBM) is associated with significant mortality and morbidity yet is difficult to diagnose and treat. We reviewed original research published in the last 2 years, since 1 January 2018, which we considered to have a major impact in advancing diagnosis, treatment and understanding of the pathophysiology of TBM meningitis in children and adults.

A pilot study of inflammatory mediators in brain extracellular fluid in paediatric TBM

Tuberculous meningitis (TBM) is the most fatal form of tuberculosis and frequently occurs in children. The inflammatory process initiates secondary brain injury processes that lead to death and disability. Much remains unknown about this cerebral inflammatory process, largely because of the difficulty in studying the brain. To date, studies have typically examined samples from sites distal to the site of disease, such as spinal cerebrospinal fluid (CSF) and blood. In this pilot study, we examined the feasibility of using direct brain microdialysis (MD) to detect inflammatory mediators in brain extracellular fluid (ECF) in TBM. MD was used to help guide neurocritical care in 7 comatose children with TBM by monitoring brain chemistry for up to 4 days. Remnant ECF fluid was stored for offline analysis. Samples of ventricular CSF, lumbar CSF and blood were collected at clinically indicated procedures for comparison. Inflammatory mediators were quantified using multiplex technology. All inflammatory markers, with the exception of interleukin (IL)-10 and IL-12p40, were detected in the ECF. Cytokine concentrations were generally lower in ECF than ventricular CSF in time-linked specimens. Individual cases showed ECF cytokine increases coinciding with marked increases in ECF glycerol or decreases in ECF glucose. Cytokine levels and glycerol were generally higher in patients with more severe disease. This is the first report of inflammatory marker analysis from samples derived directly from the brain and in high temporal resolution, demonstrating feasibility of cerebral MD to explore disease progression and possibly therapy response in TBM.

Inflammatory Markers in Cerebrospinal Fluid from Patients with Hydrocephalus: A Systematic Literature Review

OBJECTIVE

The aim of this systematic review was to evaluate existing literature on inflammatory markers in CSF from patients with hydrocephalus and identify potential markers capable of promoting hydrocephalus development and progression.

METHODS

Relevant studies published before December 3rd 2020 were identified from PubMed, Embase, and reference lists. Studies were screened for eligibility using the predefined inclusion and exclusion criteria. Data from eligible studies were extracted, and sources of bias were evaluated. We included articles written in English investigating inflammatory markers in CSF from patients with hydrocephalus and control subjects. The review was conducted according to the PRISMA guidelines by three independent reviewers.

RESULTS

Twenty-two studies analyzed CSF from 311 patients with idiopathic normal pressure hydrocephalus (iNPH), 178 with posthemorrhagic hydrocephalus (PHH), 151 with other hydrocephalus diagnoses, and 394 control subjects. Fifty-eight inflammatory markers were investigated. The CSF of iNPH patients had increased CSF levels of IL-6, IL-1β, and LRG compared with control subjects, whereas the CSF of PHH patients had increased levels of IL-6, IL-18, and VEGF. CSF from patients with "other hydrocephalus diagnoses" had elevated IFN-γ compared to control subjects, and VEGF was increased in congenital hydrocephalus, spina bifida, and hydrocephalus associated with tuberculous meningitis compared with controls.

CONCLUSION

IL-6, IL-1β, LRG, IL-18, VEGF, and IFN-γ are elevated in CSF from patients with hydrocephalus and may be involved in promotion of hydrocephalus development and progression. They may serve as novel disease biomarkers, and their signaling pathways may represent targets for pharmacological management of hydrocephalus.

Recent Developments in Tuberculous Meningitis Pathogenesis and Diagnostics

The pathogenesis of Tuberculous meningitis (TBM) is poorly understood, but contemporary molecular biology technologies have allowed for recent improvements in our understanding of TBM. For instance, neutrophils appear to play a significant role in the immunopathogenesis of TBM, and either a paucity or an excess of inflammation can be detrimental in TBM. Further, severity of HIV-associated immunosuppression is an important determinant of inflammatory response; patients with the advanced immunosuppression (CD4+ T-cell count of <150 cells/μL) having higher CSF neutrophils, greater CSF cytokine concentrations and higher mortality than those with CD4+ T-cell counts > 150 cells/μL. Host genetics may also influence outcomes with LT4AH genotype predicting inflammatory phenotype, steroid responsiveness and survival in Vietnamese adults with TBM. Whist in Indonesia, CSF tryptophan level was a predictor of survival, suggesting tryptophan metabolism may be important in TBM pathogenesis. These varying responses mean that we must consider whether a "one-size-fits-all" approach to anti-bacillary or immunomodulatory treatment in TBM is truly the best way forward. Of course, to allow for proper treatment, early and rapid diagnosis of TBM must occur. Diagnosis has always been a challenge but the field of TB diagnosis is evolving, with sensitivities of at least 70% now possible in less than two hours with GeneXpert MTB/Rif Ultra. In addition, advanced molecular techniques such as CRISPR-MTB and metagenomic next generation sequencing may hold promise for TBM diagnosis. Host-based biomarkers and signatures are being further evaluated in childhood and adult TBM as adjunctive biomarkers as even with improved molecular assays, cases are still missed. A better grasp of host and pathogen behaviour may lead to improved diagnostics, targeted immunotherapy, and possibly biomarker-based, patient-specific treatment regimens.

Blood Biomarkers for Detection of Brain Injury in COVID-19 Patients

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus attacks multiple organs of coronavirus disease 2019 (COVID-19) patients, including the brain. There are worldwide descriptions of neurological deficits in COVID-19 patients. Central nervous system (CNS) symptoms can be present early in the course of the disease. As many as 55% of hospitalized COVID-19 patients have been reported to have neurological disturbances three months after infection by SARS-CoV-2. The mutability of the SARS-COV-2 virus and its potential to directly affect the CNS highlight the urgency of developing technology to diagnose, manage, and treat brain injury in COVID-19 patients. The pathobiology of CNS infection by SARS-CoV-2 and the associated neurological sequelae of this infection remain poorly understood. In this review, we outline the rationale for the use of blood biomarkers (BBs) for diagnosis of brain injury in COVID-19 patients, the research needed to incorporate their use into clinical practice, and the improvements in patient management and outcomes that can result. BBs of brain injury could potentially provide tools for detection of brain injury in COVID-19 patients. Elevations of BBs have been reported in cerebrospinal fluid (CSF) and blood of COVID-19 patients. BB proteins have been analyzed in CSF to detect CNS involvement in patients with infectious diseases, including human immunodeficiency virus and tuberculous meningitis. BBs are approved by the U.S. Food and Drug Administration for diagnosis of mild versus moderate traumatic brain injury and have identified brain injury after stroke, cardiac arrest, hypoxia, and epilepsy. BBs, integrated with other diagnostic tools, could enhance understanding of viral mechanisms of brain injury, predict severity of neurological deficits, guide triage of patients and assignment to appropriate medical pathways, and assess efficacy of therapeutic interventions in COVID-19 patients.

Effect of Dexmedetomidine Hydrochloride on perioperative inflammation and postoperative lung infection in patients with spinal tuberculosis

Objective

To explore the effect of dexmedetomidine hydrochloride on perioperative inflammation and postoperative lung infection in patients with spinal tuberculosis.

Method

A double-blind control observation was conducted in spinal tuberculosis patients with the use of general anesthesia during the operation. A total of 171 spinal tuberculosis patients who received endotracheal intubation for general anesthesia in Henan University of Chinese Medicine from January 2017 to April 2019 were included. The concentration changes in serum TNF-α and IL-6 were recorded at one hour, six hour and one day after the operation. The incidence of postoperative pulmonary complications of patients were also evaluated.

Results

The results showed that in the experimental group compared with the control group, serum TNF-α and IL-6 concentrations one hour, six hour and one day after the operation were significantly lower (P<0.05). The rate of postoperative pulmonary complications was lower in the experimental group than that in the control group (P<0.05).

Conclusion

Dexmedetomidine hydrochloride has obvious anti-inflammatory effects and can reduce the incidence of pulmonary complications after surgery.

International Survey Reveals Opportunities to Improve Tuberculous Meningitis Management and the Need for Standardized Guidelines

BACKGROUND

Tuberculous meningitis (TBM) is a medical emergency, yet there are no standardized treatment guidelines for the medical or neurosurgical management of these patients and little data on neurocritical care. We conducted an international survey to understand current medical and neurosurgical TBM management and resource availability to provide baseline data needed for future multicenter trials addressing unanswered clinical research questions and the establishment of standardized guidelines.

METHODS

An online survey of 77 questions covering medical and neurosurgical TBM management aimed at clinicians/nurses treating TBM was distributed as an anonymous link through email invitation, international organizations' membership distribution, and direct links on organizational webpages or social media. The survey remained open for 5 months. Data were summarized with frequencies and percentages.

RESULTS

The survey had 222 responses from 43 countries representing 6 continents. Most respondents were from tertiary care facilities, with broad access to medical and neurosurgical resources. There was significant heterogeneity in general supportive care, and TBM-specific management demonstrated considerable divergence from current standard-of-care practices. The lack of standardized guidelines was identified as a major challenge in TBM management. General and neurocritical care were largely absent. Resources for bedside supportive care and noninvasive monitoring were broadly accessible.

CONCLUSIONS

These findings suggest that current TBM management could be improved by the establishment of internationally accepted treatment guidelines based on available evidence, and that numerous centers have resources available to participate in future multicenter trials, even for basic interventions, that may further improve patient outcomes globally.

Multifunctional neuron-specific enolase: its role in lung diseases

Neuron-specific enolase (NSE), also known as gamma (γ) enolase or enolase-2 (Eno2), is a form of glycolytic enolase isozyme and is considered a multifunctional protein. NSE is mainly expressed in the cytoplasm of neurons and neuroendocrine cells, especially in those of the amine precursor uptake and decarboxylation (APUD) lineage such as pituitary, thyroid, pancreas, intestine and lung. In addition to its well-established glycolysis function in the cytoplasm, changes in cell localization and differential expression of NSE are also associated with several pathologies such as infection, inflammation, autoimmune diseases and cancer. This article mainly discusses the role and diagnostic potential of NSE in some lung diseases.

Recent Developments in Tuberculous Meningitis Pathogenesis and Diagnostics

The pathogenesis of Tuberculous meningitis (TBM) is poorly understood, but contemporary molecular biology technologies have allowed for recent improvements in our understanding of TBM. For instance, neutrophils appear to play a significant role in the immunopathogenesis of TBM, and either a paucity or an excess of inflammation can be detrimental in TBM. Further, severity of HIV-associated immunosuppression is an important determinant of inflammatory response; patients with the advanced immunosuppression (CD4+ T-cell count of <150 cells/μL) having higher CSF neutrophils, greater CSF cytokine concentrations and higher mortality than those with CD4+ T-cell counts > 150 cells/μL. Host genetics may also influence outcomes with LT4AH genotype predicting inflammatory phenotype, steroid responsiveness and survival in Vietnamese adults with TBM. Whist in Indonesia, CSF tryptophan level was a predictor of survival, suggesting tryptophan metabolism may be important in TBM pathogenesis. These varying responses mean that we must consider whether a "one-size-fits-all" approach to anti-bacillary or immunomodulatory treatment in TBM is truly the best way forward. Of course, to allow for proper treatment, early and rapid diagnosis of TBM must occur. Diagnosis has always been a challenge but the field of TB diagnosis is evolving, with sensitivities of at least 70% now possible in less than two hours with GeneXpert MTB/Rif Ultra. In addition, advanced molecular techniques such as CRISPR-MTB and metagenomic next generation sequencing may hold promise for TBM diagnosis. Host-based biomarkers and signatures are being further evaluated in childhood and adult TBM as adjunctive biomarkers as even with improved molecular assays, cases are still missed. A better grasp of host and pathogen behaviour may lead to improved diagnostics, targeted immunotherapy, and possibly biomarker-based, patient-specific treatment regimens.

Standardized approaches for clinical sampling and endpoint ascertainment in tuberculous meningitis studies

Tuberculous meningitis (TBM), the most severe manifestation of tuberculosis, has poorly understood immunopathology and high mortality and morbidity despite antituberculous therapy. This calls for accelerated clinical and basic science research in this field. As TBM disproportionally affects poorer communities, studies are often performed in resource-limited environments, creating challenges for data collection and harmonisation. Comparison of TBM studies has been hampered by variation in sampling strategies, study design and choice of study endpoints.  Based on literature review and expert consensus, this paper provides firstly, practical recommendations to enable thorough diagnostic, pathophysiological and pharmacokinetic studies using clinical samples, and facilitates better data aggregation and comparisons across populations and settings. Secondly, we discuss clinically relevant study endpoints, including neuroimaging, functional outcome, and cause of death, with suggestions of how these could be applied in different designs for future TBM studies.

Standardized approaches for clinical sampling and endpoint ascertainment in tuberculous meningitis studies

Tuberculous meningitis (TBM), the most severe manifestation of tuberculosis, has poorly understood immunopathology and high mortality and morbidity despite antituberculous therapy. This calls for accelerated clinical and basic science research in this field. As TBM disproportionally affects poorer communities, studies are often performed in resource-limited environments, creating challenges for data collection and harmonisation. Comparison of TBM studies has been hampered by variation in sampling strategies, study design and choice of study endpoints.  Based on literature review and expert consensus, this paper provides firstly, practical recommendations to enable thorough diagnostic, pathophysiological and pharmacokinetic studies using clinical samples, and facilitates better data aggregation and comparisons across populations and settings. Secondly, we discuss clinically relevant study endpoints, including neuroimaging, functional outcome, and cause of death, with suggestions of how these could be applied in different designs for future TBM studies.

The value of glial fibrillary acidic protein levels in the diagnosis and prognosis of subarachnoid hemorrhage

Background:

Subarachnoid hemorrhages is an important emergency condition due to its high morbidity and mortality. Early diagnosis and rapid intervention are very important to prevent poor clinical outcome of this disease.

Objective:

The aim of this study was to determine the value of glial fibrillary acidic protein in the diagnosis and prognosis of subarachnoid hemorrhage.

Methods:

Patients presenting to the emergency department and undergoing computerized tomography and/or lumbar puncture due to suspicion of subarachnoid hemorrhage were included in this prospective study. Based on the computerized tomography–lumbar puncture results, cases were divided into subarachnoid hemorrhage group and non–subarachnoid hemorrhage control group. Subarachnoid hemorrhage patients were classified on the basis of severity of subarachnoid hemorrhage and were classified as good or poor clinical outcome groups based on Glasgow Outcome Scores. Glial fibrillary acidic protein levels were then compared.

Results:

A total of 111 patients were evaluated due to suspicion of subarachnoid hemorrhage and diagnosed with subarachnoid hemorrhage (n = 73) or without subarachnoid hemorrhage (n = 38). Cerebrospinal fluid glial fibrillary acidic protein levels were significantly higher in the subarachnoid hemorrhage group than in the non–subarachnoid hemorrhage group (p < 0.001) (median (25%–75%): 11.62 (2.64–68.04) and 2.26 (1.5–4.83), respectively). Serum glial fibrillary acidic protein levels of the subarachnoid hemorrhage patients with poor clinical outcomes were higher than those of subarachnoid hemorrhage patients with good clinical outcomes (p = 0.003) and cerebrospinal fluid glial fibrillary acidic protein levels were similar (p = 0.379). Glial fibrillary acidic protein levels at the time of presentation exhibited a low level of correlation with Glasgow coma score, World Federation of Neurological Surgeons scale, Hunter–Hess Scale, Ogilvy–Carter Scale, Glasgow Outcome Score, and modified Rankin score.

Conclusion:

Cerebrospinal fluid glial fibrillary acidic protein levels may be a valuable diagnostic parameter at the time of presentation for diagnosis of subarachnoid hemorrhage. And also serum glial fibrillary acidic protein levels may be useful in predicting subarachnoid hemorrhage patients with poor clinical outcomes.

Elevated Matrix Metalloproteinase Concentrations Offer Novel Insight Into Their Role in Pediatric Tuberculous Meningitis

We collected lumbar and ventricular cerebrospinal fluid and serum from 40 children treated for tuberculous meningitis and measured the concentrations of gelatinases and their inhibitors. The concentrations of matrix metalloproteinase 9 (MMP-9), MMP-2, tissue inhibitor of metalloproteinase 1 (TIMP-1), and TIMP-2 were significantly elevated in the lumbar CSF samples, and we found interesting dynamics for MMP-9 that offer novel insight into its role in pediatric patients with tuberculous meningitis.

Neonatal hydrocephalus leads to white matter neuroinflammation and injury in the corpus callosum of Ccdc39 hydrocephalic mice

OBJECTIVE

The authors sought to determine if hydrocephalus caused a proinflammatory state within white matter as is seen in many other forms of neonatal brain injury. Common causes of hydrocephalus (such as trauma, infection, and hemorrhage) are inflammatory insults themselves and therefore confound understanding of how hydrocephalus itself affects neuroinflammation. Recently, a novel animal model of hydrocephalus due to a genetic mutation in the Ccdc39 gene has been developed in mice. In this model, ciliary dysfunction leads to early-onset ventriculomegaly, astrogliosis, and reduced myelination. Because this model of hydrocephalus is not caused by an antecedent proinflammatory insult, it was utilized to study the effect of hydrocephalus on inflammation within the white matter of the corpus callosum.

METHODS

A Meso Scale Discovery assay was used to measure levels of proinflammatory cytokines in whole brain from animals with and without hydrocephalus. Immunohistochemistry was used to measure macrophage activation and NG2 expression within the white matter of the corpus callosum in animals with and without hydrocephalus.

RESULTS

In this model of hydrocephalus, levels of cytokines throughout the brain revealed a more robust increase in classic proinflammatory cytokines (interleukin [IL]-1β, CXCL1) than in immunomodulatory cytokines (IL-10). Increased numbers of macrophages were found within the corpus callosum. These macrophages were polarized toward a proinflammatory phenotype as assessed by higher levels of CD86, a marker of proinflammatory macrophages, compared to CD206, a marker for antiinflammatory macrophages. There was extensive structural damage to the corpus callosum of animals with hydrocephalus, and an increase in NG2-positive cells.

CONCLUSIONS

Hydrocephalus without an antecedent proinflammatory insult induces inflammation and tissue injury in white matter. Future studies with this model will be useful to better understand the effects of hydrocephalus on neuroinflammation and progenitor cell development. Antiinflammatory therapy for diseases that cause hydrocephalus may be a powerful strategy to reduce tissue damage.

Radiosynthesis and PET Bioimaging of 76Br-Bedaquiline in a Murine Model of Tuberculosis

Bedaquiline is a promising drug against tuberculosis (TB), but limited data are available on its intralesional pharmacokinetics. Moreover, current techniques rely on invasive tissue resection, which is difficult in humans and generally limited even in animals. In this study, we developed a novel radiosynthesis for 76Br-bedaquiline and performed noninvasive, longitudinal whole-body positron emission tomography (PET) in live, Mycobacterium tuberculosis-infected mice over 48 h. After the intravenous injection, 76Br-bedaquiline distributed to all organs and selectively localized to adipose tissue and liver, with excellent penetration into infected lung lesions (86%) and measurable penetration into the brain parenchyma (15%). Ex vivo high resolution, two-dimensional autoradiography, and same section hematoxylin/eosin and immunofluorescence provided detailed intralesional drug biodistribution. PET bioimaging and high-resolution autoradiography are novel techniques that can provide detailed, multicompartment, and intralesional pharmacokinetics of new and existing TB drugs. These technologies can significantly advance efforts to optimize drug dosing.

Outcomes measures in children after acute central nervous system infections and malaria

PURPOSE OF REVIEW

Acute central nervous system (CNS) infections in children result in significant mortality and neurologic morbidity worldwide. This article summarizes the recent pediatric literature published on outcomes measures used after acute infectious meningitis, encephalitis, and cerebral malaria, and highlights ongoing research efforts to standardize outcomes measurements. Search terms were geared toward functional, cognitive, behavioral, and other outcome assessments.

RECENT FINDINGS

Recent data suggest that, depending on microbiological cause, there are differences in currently used outcome measures following acute CNS infections. Outcomes assessments include a variety of formal psychological tests (structured interviews and neuropsychological tests of cognitive and motor functioning) and dichotomized or ordinal scales. Standardization of outcome measures, however, is lacking. Global efforts to standardize outcomes that encompass both the child and family are ongoing.

SUMMARY

Centers worldwide can track and measure a variety of cognitive, behavioral, and functional outcomes after acute CNS infections. Standardized documentation and coding of clinically important outcomes is needed. Further research to evaluate effective practices using acute adjunctive and rehabilitation therapies will be aided by outcome measure standardization.

Knowledge gaps and research priorities in tuberculous meningitis

Tuberculous meningitis (TBM) is the most severe and disabling form of tuberculosis (TB), accounting for around 1-5% of the global TB caseload, with mortality of approximately 20% in children and up to 60% in persons co-infected with human immunodeficiency virus even in those treated. Relatively few centres of excellence in TBM research exist and the field would therefore benefit from greater co-ordination, advocacy, collaboration and early data sharing. To this end, in 2009, 2015 and 2019 we convened the TBM International Research Consortium, bringing together approximately 50 researchers from five continents. The most recent meeting took place on 1 st and 2 nd March 2019 in Lucknow, India. During the meeting, researchers and clinicians presented updates in their areas of expertise, and additionally presented on the knowledge gaps and research priorities in that field. Discussion during the meeting was followed by the development, by a core writing group, of a synthesis of knowledge gaps and research priorities within seven domains, namely epidemiology, pathogenesis, diagnosis, antimicrobial therapy, host-directed therapy, critical care and implementation science. These were circulated to the whole consortium for written input and feedback. Further cycles of discussion between the writing group took place to arrive at a consensus series of priorities. This article summarises the consensus reached by the consortium concerning the unmet needs and priorities for future research for this neglected and often fatal disease.

Recent Developments in Tuberculous Meningitis Pathogenesis and Diagnostics

The pathogenesis of Tuberculous meningitis (TBM) is poorly understood, but contemporary molecular biology technologies have allowed for recent improvements in our understanding of TBM. For instance, neutrophils appear to play a significant role in the immunopathogenesis of TBM, and either a paucity or an excess of inflammation can be detrimental in TBM. Further, severity of HIV-associated immunosuppression is an important determinant of inflammatory response; patients with the advanced immunosuppression (CD4+ T-cell count of <150 cells/μL) having higher CSF neutrophils, greater CSF cytokine concentrations and higher mortality than those with CD4+ T-cell counts > 150 cells/μL. Host genetics may also influence outcomes with LT4AH genotype predicting inflammatory phenotype, steroid responsiveness and survival in Vietnamese adults with TBM. Whist in Indonesia, CSF tryptophan level was a predictor of survival, suggesting tryptophan metabolism may be important in TBM pathogenesis. These varying responses mean that we must consider whether a "one-size-fits-all" approach to anti-bacillary or immunomodulatory treatment in TBM is truly the best way forward. Of course, to allow for proper treatment, early and rapid diagnosis of TBM must occur. Diagnosis has always been a challenge but the field of TB diagnosis is evolving, with sensitivities of at least 70% now possible in less than two hours with GeneXpert MTB/Rif Ultra. In addition, advanced molecular techniques such as CRISPR-MTB and metagenomic next generation sequencing may hold promise for TBM diagnosis. Host-based biomarkers and signatures are being further evaluated in childhood and adult TBM as adjunctive biomarkers as even with improved molecular assays, cases are still missed. A better grasp of host and pathogen behaviour may lead to improved diagnostics, targeted immunotherapy, and possibly biomarker-based, patient-specific treatment regimens.

Noninvasive 11C-rifampin positron emission tomography reveals drug biodistribution in tuberculous meningitis

Tuberculous meningitis (TBM) is a devastating form of tuberculosis (TB), and key TB antimicrobials, including rifampin, have restricted brain penetration. A lack of reliable data on intralesional drug biodistribution in infected tissues has limited pharmacokinetic (PK) modeling efforts to optimize TBM treatments. Current methods to measure intralesional drug distribution rely on tissue resection, which is difficult in humans and generally limited to a single time point even in animals. In this study, we developed a multidrug treatment model in rabbits with experimentally induced TBM and performed serial noninvasive dynamic ¹¹C-rifampin positron emission tomography (PET) over 6 weeks. Area under the curve brain/plasma ratios were calculated using PET and correlated with postmortem mass spectrometry. We demonstrate that rifampin penetration into infected brain lesions is limited, spatially heterogeneous, and decreases rapidly as early as 2 weeks into treatment. Moreover, rifampin concentrations in the cerebrospinal fluid did not correlate well with those in the brain lesions. First-in-human ¹¹C-rifampin PET performed in a patient with TBM confirmed these findings. PK modeling predicted that rifampin doses (≥30 mg/kg) were required to achieve adequate intralesional concentrations in young children with TBM. These data demonstrate the proof of concept of PET as a clinically translatable tool to noninvasively measure intralesional antimicrobial distribution in infected tissues.