Tuberculous meningitis (TBM) is characterized by disruption of the blood-brain barrier (BBB), cerebral edema and increased intracranial pressure (ICP). Vascular endothelial growth factor (VEGF) is a potent vascular permeability factor and a mediator of brain edema.
To investigate whether in children with TBM disruption of the BBB relates to VEGF production and to assess the effect of corticosteroids on Mycobacterium tuberculosis-induced VEGF production by mononuclear leukocytes.
Blood and CSF samples were collected from 26 children with stage 2-3 TBM and 20 controls. All patients received antituberculous and adjuvant corticosteroid therapy. Children were evaluated by ICP recording, computerized tomography scanning and outcome assessment at 6 months follow-up. BBB disruption was quantified by cerebrospinal fluid (CSF)-serum albumin ratios. VEGF concentrations were measured by enzyme-linked immunosorbent assay. In vitro human monocytic THP-1 cells were stimulated with M. tuberculosis sonicate or culture supernatant, and VEGF production was measured in the presence or absence of corticosteroids.
CSF VEGF concentrations were significantly higher in TBM patients than in the controls and correlated with mononuclear cell counts (r = 0.64; P = 0.001) and CSF-serum albumin ratio (r = 0.49; P = 0.015). CSF VEGF did not significantly correlate with elevated ICP. In vitro induction of VEGF production by M. tuberculosis sonicate or culture supernatant could be completely abrogated by corticosteroid treatment.
Inflammatory cells secrete VEGF during TBM. CSF VEGF correlates with BBB disruption. Inhibition of VEGF may explain part of the clinical effect of adjuvant corticosteroid therapy in TBM.
"VEGF-mediated neovascularization may enhance the oxygen supply. Besides, VEGF that is produced intrathecally may contribute to disruption of the blood-brain barrier (BBB)9,32). Thus, the bacteria introduced at the monent of VP shunt surgery may easily break into the brain tissue and vascular channels through the disrupted BBB and the increased vascular networks probably provide nutrients and oxygen to the bacteria. "
[Show abstract][Hide abstract] ABSTRACT: The aim of this study is to determine the association between the cerebrospinal fluid (CSF) biomarkers and inflammation, and the predictive value of these CSF biomarkers for subsequent shunt associated infection.
We obtained CSF samples from the patients with hydrocephalus during ventriculoperitoneal (VP) shunt operations. Twenty-two patients were enrolled for this study and divided into 3 groups: subarachnoid hemorrhage (SAH)-induced hydrocephalus, idiopathic normal pressure hydrocephalus (INPH) and hydrocephalus with a subsequent shunt infection. We analyzed the transforming growth factor-β1, tumor necrosis factor-α, vascular endothelial growth factor (VEGF) and total tau in the CSF by performing enzyme-linked immunosorbent assay. The subsequent development of shunt infection was confirmed by the clinical presentations, the CSF parameters and CSF culture from the shunt devices.
The mean VEGF concentration (±standard deviation) in the CSF of the SAH-induced hydrocephalus, INPH and shunt infection groups was 236±138, 237±80 and 627±391 pg/mL, respectively. There was a significant difference among the three groups (p=0.01). Between the SAH-induced hydrocephalus and infection groups and between the INPH and infection groups, there was a significant difference of the VEGF levels (p<0.01). However, the other marker levels did not differ among them.
The present study showed that only the CSF VEGF levels are associated with the subsequent development of shunt infection. Our results suggest that increased CSF VEGF could provide a good condition for bacteria that are introduced at the time of surgery to grow in the brain, rather than reflecting a sequel of bacterial infection before VP shunt.
Journal of Korean Neurosurgical Society 06/2012; 51(6):328-33. DOI:10.3340/jkns.2012.51.6.328 · 0.64 Impact Factor
"Greater antigen-stimulated levels of VEGF in combination with other cytokines in the supernatant of interferon-γ release assays were found to accurately differentiate active disease from latent TB infection in one study . Furthermore, increased VEGF levels in plasma and/or CSF were found to correlate with activity in neurotuberculosis , , . However, it is unlikely that local (i.e., aqueous or vitreous) VEGF levels can serve as a biomarker of active intraocular TB since VEGF expression may be upregulated as a result of many different posterior segment inflammatory conditions , . "
[Show abstract][Hide abstract] ABSTRACT: The pathogenesis of intraocular tuberculosis remains poorly understood partly due to the lack of adequate animal models that accurately simulate human disease. Using a recently developed model of ocular tuberculosis following aerosol infection of guinea pigs with Mycobacterium tuberculosis, we studied the microbiological, histological, and clinical features of intraocular tuberculosis infection. Viable tubercle bacilli were cultivated from all eyes by Day 56 after aerosol delivery of ∼200 bacilli to guinea pig lungs. Choroidal tuberculous granulomas showed reduced oxygen tension, as evidenced by staining with the hypoxia-specific probe pimonidazole, and expression of vascular endothelial growth factor (VEGF) was detected in the retinal pigment epithelium (RPE) and photoreceptors. Fundoscopic examination of M. tuberculosis-infected guinea pig eyes revealed altered vascular architecture and chorioretinal hemorrhage by Day 56 after infection. This model may be useful in further elucidating the pathogenesis of ocular tuberculosis, as well as in developing tools for diagnosis and assessment of antituberculosis treatment responses in the eye.
PLoS ONE 12/2011; 6(12):e28383. DOI:10.1371/journal.pone.0028383 · 3.23 Impact Factor
"Loss of BBB structural integrity and function plays a pivotal role in the pathogenesis of many diseases of the central nervous system (CNS). The BBB is altered in many clinical settings including brain trauma (Unterberg et al, 2004), focal brain ischemia (Latour et al, 2004), meningitis (van der et al, 2004), brain tumor (Lee et al, 2006), stroke (Cipolla et al, 2004), inflammation (Stamatovic et al, 2006), Alzheimer's disease (Kalaria, 1992), and multiple sclerosis (Minagar and Alexander, 2003). In ischemic brain injury, matrix metalloproteinases (MMPs) contribute to the disruption of the BBB leading to vasogenic edema, and to the influx of leukocytes into the CNS (Gasche et al, 2006). "
[Show abstract][Hide abstract] ABSTRACT: In evaluating drugs that enter or are excluded from the brain, novel pharmaceutical strategies are needed. For this reason, we have developed a humanized Dynamic In vitro Blood-Brain Barrier model (hDIV-BBB) based on a novel human brain vascular endothelial cell line (HCMEC/D3), which closely mimics the BBB in vivo. In this system, HCMEC/D3 was grown in the lumen of hollow microporous fibers and exposed to a physiological pulsatile flow. Comparison with well-established humanized DIV-BBB models (based on human brain and non-brain vascular endothelial cells co-cultured with abluminal astrocytes) demonstrated that HCMEC/D3 cells cultured under flow conditions maintain in vitro physiological permeability barrier properties of the BBB in situ even in the absence of abluminal astrocytes. Measurements of glucose metabolism demonstrated that HCMEC/D3 cells retain an aerobic metabolic pathway. Permeability to sucrose and two relevant central nervous system drugs showed that the HCMEC/D3 cells grown under dynamic conditions closely mimic the physiological permeability properties of the BBB in situ (slope=0.93). Osmotic disruption of the BBB was also successfully achieved. Peak BBB opening in the DIV-BBB lasted from 20 to 30 mins and was completely reversible. Furthermore, the sequence of flow cessation/reperfusion in the presence of leukocytes led to BBB failure as demonstrated by a biphasic decrease in transendothelial electrical resistance. Additionally, BBB failure was paralleled by the intraluminal release of proinflammatory factors (interleukin-6 and interleukin-1beta) and matrix metalloproteinase-9 (MMP-9). Pretreatment with ibuprofen (0.125 mmol/L) prevented BBB failure by decreasing the inflammatory response after flow cessation/reperfusion.
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