Possible role for vascular cell proliferation in cerebral vasospasm after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: During vasospasm after subarachnoid hemorrhage (SAH), cerebral blood vessels show structural changes consistent with the actions of vascular mitogens. We measured platelet-derived vascular growth factors (PDGFs) in the cerebrospinal fluid (CSF) of patients after SAH and tested the effect of these factors on cerebral arteries in vivo and in vitro. METHODS: CSF was sampled from 14 patients after SAH, 6 patients not suffering SAH, and 8 normal controls. ELISA was performed for PDGF-AB, transforming growth factor-beta1, and vascular endothelial growth factor. A mouse model was used to compare cerebral vascular cell proliferation and PDGF staining in SAH compared with sham-operated controls. Normal human pial arteries were incubated for 7 days in vitro, 2 groups with human blood clot and 1 with and 1 without PDGF antibodies. RESULTS: PDGF-AB concentrations in CSF from SAH patients were significantly higher than those from non-SAH patients and normal controls, both during the first week after SAH and for all time points measured. Smooth muscle and fibroblast proliferation was observed after SAH in the mouse model, and this cellular replication was observed in conjunction with PDGF protein at the sites of thrombus. In human pial arteries, localized thrombus stimulated vessel wall proliferation, and proliferation was blocked by neutralizing antibodies directed against PDGFs. CONCLUSIONS: Vascular mitogens are increased in the CSF of patients after SAH. Proliferation of cells in the vascular wall is associated with perivascular thrombus. Cellular proliferation and subsequent vessel wall thickening may contribute to the syndrome of delayed cerebral vasospasm.

Vascular endothelial growth factor in the cerebrospinal fluid of infants who died of sudden infant death syndrome: evidence for antecedent hypoxia.

OBJECTIVES: Recurrent hypoxemia has been proposed as an important pathophysiological mechanism underlying sudden infant death syndrome (SIDS). However, conflicting results emerged when xanthines were used as markers for hypoxia. The vascular endothelial growth factor (VEGF) gene is highly sensitive to changes in tissue partial oxygen tension, and changes in genomic and protein expression occur even after changes in oxygenation within the physiologic range. METHODS: For determining whether hypoxia precedes SIDS, VEGF levels were measured using an enzyme-linked immunosorbent assay in the cerebrospinal fluid (CSF) of 51 SIDS infants and in 33 additional control infants who died of an identifiable cause. In addition, 6 rats that had a chronically implanted catheter in the lateral ventricle were exposed to a short hypoxic challenge, and VEGF concentrations were measured in CSF at various time points for 24 hours. Another set of 6 rats were killed with a pentobarbital overdose, and VEGF CSF levels were obtained at different time points after death. RESULTS: Mean VEGF concentrations in CSF were 308.2 +/- 299.1 pg/dL in the SIDS group and 85.1 +/- 82.9 pg/dL in those who died of known causes. Mean postmortem delay averaged 22 hours for both groups. In rat experiments, hypoxic exposures induced time-dependent increases in VEGF, peaking at 12 hours and returning to baseline at 24 hours. Postmortem duration in the animals was associated with gradual increases in VEGF that reached significance only at 36 hours. CONCLUSIONS: We conclude that VEGF CSF concentrations are significantly higher in infants who die of SIDS. We postulate that hypoxia is a frequent event that precedes the sudden and unexpected death of these infants.

Vascular endothelial growth factor and erythropoietin concentrations in cerebrospinal fluid of children with hydrocephalus.

INTRODUCTION: Hypoxia induces transcription of vascular endothelial growth factor (VEGF) and erythropoietin (EPO) genes. We set up the hypothesis that elevated intracranial pressure in patients with hydrocephalus triggers release of VEGF and EPO into cerebrospinal fluid (CSF). METHODS AND RESULTS: VEGF and EPO concentrations, measured in 57 CSF aliquots obtained from infants and children with hydrocephalus undergoing surgery or therapeutic taps, were significantly elevated compared with those in 41 CSF aliquots of sex- and age-matched children undergoing routine diagnostic lumbar puncture for unrelated reasons ( P<0.001 and P=0.015, respectively). In hydrocephalus samples, median (interquartile range) VEGF concentrations were 135 (35-410) pg/ml, and 4 of 57 hydrocephalus samples had a VEGF concentration below the detection limit (1 pg/ml), compared with 38 of 41 control samples. Erythropoietin was undetectable (<0.1 pg/ml) in 34 of 57 hydrocephalus samples and in 34 of 41 controls. CONCLUSION: We conclude that conditions necessitating surgical intervention in hydrocephalus patients result in increased CSF concentrations of VEGF and EPO.

Gene transfer of hepatocyte growth factor to subarachnoid space in cerebral hypoperfusion model.

Although cerebral hypoperfusion caused by cerebral occlusive disease leads to cerebral ischemic events, an effective treatment has not yet been established. Recently, a novel therapeutic strategy for ischemic disease using angiogenic growth factors to expedite and/or augment collateral artery development has been proposed. Therapeutic angiogenesis might be useful for the treatment of cerebral occlusive disease. Hepatocyte growth factor (HGF) is a potent angiogenic factor, in addition to vascular endothelial growth factor (VEGF), whereas in the nervous system HGF also acts as neurotrophic factor. Therefore, we hypothesized that gene transfer of these angiogenic growth factors could induce angiogenesis, thus providing an effective therapy for cerebral hypoperfusion or stroke. In this study, we employed a highly efficient gene transfer method, the viral envelop (Hemagglutinating Virus of Japan [HVJ]-liposome) method, because we previously documented that beta-galactosidase gene could be transfected into the brain by the HVJ-liposome method. Indeed, we confirmed wide distribution of transgene expression using beta-galactosidase via injection into the subarachnoid space. Of importance, transfection of HGF or VEGF gene into the subarachnoid space 7 days before occlusion induced angiogenesis on the brain surface as assessed by alkaline phosphatase staining (P<0.01). In addition, significant improvement of cerebral blood flow (CBF) was observed by laser Doppler imaging (LDI) 7 days after occlusion (P<0.01). Unexpectedly, transfection of HGF or VEGF gene into the subarachnoid space immediately after occlusion of the bilateral carotid arteries also induced angiogenesis on the brain surface and had a significant protective effect on the impairment of CBF by carotid occlusion (P<0.01). Interestingly, coinjection of recombinant HGF with HGF gene transfer revealed a further increase in CBF (P<0.01). Here, we demonstrated successful therapeutic angiogenesis using HGF or VEGF gene transfer into the subarachnoid space to improve cerebral hypoperfusion, thus providing a new therapeutic strategy for cerebral ischemic disease.

Increased intrathecal levels of the angiogenic factors VEGF and TGF-beta in Alzheimer's disease and vascular dementia.

The aim of the present study was to investigate, in patients with Alzheimer's disease (AD), and vascular dementia (VAD), patterns of local release of vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-beta), two cytokines having a pivotal role in hypoxia-induced angiogenesis. The intrathecal levels of these molecules were related to the clinical severity of these diseases and to the intrathecal levels of beta-amyloid protein. Significantly increased cerebrospinal fluid (CSF) levels of both VEGF and TGF-beta were observed in 20 patients with AD and in 26 patients with VAD compared to healthy controls. Interestingly, there was significant correlation between the CSF levels of TGF-beta and VEGF in all the individuals studied. Our study demonstrates, both in patients with AD and in patients with VAD, an intrathecal production of VEGF, a cytokine which plays a pivotal role in angiogenesis. These results suggest that vascular factors might not only play a role in the pathogenesis of VAD but also in the pathogenesis of AD. In addition, we show in AD and VAD an intrathecal production of TGF-beta, a cytokine exerting on one hand anti-inflammatory and angiogenic properties, but on the other promoting amyloidogenesis.

Specific pattern of growth factor distribution in chronic subdural hematoma (CSH): evidence for an angiogenic disease.

BACKGROUND: The aim of this prospective study was to evaluate the significance of growth factors as determinants of the pathological degree of neovascularisation found in the parietal neomembrane of chronic subdural hematoma (CSH). Thus far the pathogenesis of the vascularisation has not been elucidated. METHOD: The concentrations of growth factors, i.e. vascular endothelial derived growth factor (VEGF), basic fibroblast growth factor (bFGF) and platelet derived growth factor (PDGF) were determined using ELISA technique in hematoma fluid and serum of 20 patients with uni- or bilateral CSH. For comparison, growth factor concentrations were determined in cerebrospinal fluid (CSF) of patients undergoing diagnostic myelography. FINDINGS: Concentrations of VEGF and bFGF were significantly (p < 0.001) increased in the hematoma fluid as compared with serum (VEGFh = 8.142 pg/ml, bFGFh = 8.7 pg/ml versus VEGFS = 368 pg/ml, bFGF, = 1.8 pg/ml). In contrast, PDGF concentration was significantly (p < 0.001) lower in the hematoma (PDGFh = 3,456 pg/ml versus PDGF, = 31,937 pg/ml). The serum levels for VEGF, bFGF and PDGF in CSH patients lay within the range of normal volunteers. No growth factors were found in normal CSF. INTERPRETATION: These results reveal a specific distribution pattern of growth factors in CSH patients. This pattern suggests that CSH may be considered a member of the angiogenic disease family.

Vascular endothelial growth factor in chronic subdural haematomas.

OBJECTIVE: To elucidate molecular aspects of the mechanisms of expansion of chronic subdural haematomas (CSH), we examined the expression of two representative angiogenic factors, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in CSH. METHODS: We quantified VEGF and bFGF in haematoma fluid and serum of 20 patients with CSH using an enzyme-linked immunosorbent assay. Mean concentrations of VEGF in the haematoma fluid (10277 pg/ml) and in serum, (355 pg/ml) were much greater than those of bFGF (haematoma, 3.04 pg/ml; serum, 4.74 pg/ml). Surgical specimens, including dura and the outer membrane of the CSH were analysed by in situ hybridisation to detect VEGF mRNA. Macrophages and vascular endothelial cells in the outer membrane over expressed VEGF mRNA. CONCLUSIONS: Enhanced production of VEGF by macrophages and vascular endothelial cells in the outer membrane is thought to be pathogenetically important in CSH.

Expression of vascular endothelial growth factor in tuberculous meningitis.

The pathogenesis of tuberculous meningitis is still unclear. Recently, vascular endothelial growth factor (VEGF) was found to be associated with inflammatory diseases and we found the increased serum level of VEGF in pulmonary tuberculosis. We hypothesized that VEGF might be associated with the pathogenesis of tuberculous meningitis and measured serum and cerebrospinal fluid (CSF) levels of VEGF in 28 patients with tuberculous meningitis and 31 non-tuberculous infectious meningitis patients (13 bacterial meningitis patients, eight fungal meningitis patients and 10 patients with viral meningitis) before therapy. We examined the CSF VEGF levels 3 months after in 12 tuberculous meningitis patients. The serum and CSF levels of VEGF were significantly higher in tuberculous meningitis than in other meningitis. The decrease in titer of CSF VEGF paralleled the clinical improvement of tuberculous meningitis. Immunohistochemical staining of autopsied brains demonstrated the presence of VEGF in the inflammatory mononuclear cells of the dense fibroconnective tissue both in the subarachnoid space and surrounding the vasculitis lesion. We found the expression of VEGF in tuberculous meningitis and think that VEGF reflects its activity.

Vascular endothelial growth factor in bacterial meningitis: detection in cerebrospinal fluid and localization in postmortem brain.

Vascular endothelial growth factor (VEGF) is a potent vascular permeability factor and a mediator of brain edema. To assess the role of VEGF during bacterial meningitis, VEGF was measured in cerebrospinal fluid (CSF) and blood of 37 patients with bacterial meningitis and 51 control patients, including 16 patients with viral meningitis. Circulating VEGF levels were similar in bacterial meningitis patients and control patients. VEGF(CSF) was detected in 11 (30%) of 37 of bacterial meningitis patients (range, <25-633 pg/mL) but in none of the control patients. The median VEGF index was 6.2 (range, 0.6-42), indicating intrathecal production. Median CSF cell counts, protein levels, and CSF: serum albumin ratios were higher for patients with detectable VEGF(CSF), although the difference was not statistically significant. VEGF immunoreactivity in autopsy brain specimens was found in the inflammatory infiltrate of patients with bacterial meningitis. These results indicate that inflammatory cells secrete VEGF during bacterial meningitis and that VEGF may contribute to blood-brain barrier disruption.

Vascular endothelial growth factor in CSF: a biological marker for carcinomatous meningitis.

OBJECTIVE: To determine the value of vascular endothelial growth factor (VEGF) in CSF as a marker for carcinomatous meningitis (CM). METHODS: The concentration of VEGF was measured by ELISA in matched samples of CSF and serum collected from 162 patients. These included patients with solid tumors with CM (n = 11) or brain metastases without concomitant CM (n = 12), paraneoplastic neurologic syndromes (n = 4), viral (n = 15) and bacterial (n = 20) meningitis, and a variety of non-neoplastic and noninfectious neurologic diseases (n = 100). Using CSF/serum albumin ratios, the VEGF index was calculated to estimate the proportion of intrathecally produced VEGF. Immunohistochemical staining for VEGF was performed in a brain metastasis from a mammary carcinoma associated with CM. RESULTS: High VEGF levels (median 6,794.8 pg/mL) were found in CSF of all patients with CM, whereas VEGF levels in matched sera were comparable to other disease groups. In patients with CM, the concentration of VEGF in CSF decreased significantly following antineoplastic treatment. In CSF samples from patients with brain metastases without concomitant CM, VEGF was not detectable. Median VEGF concentration in CSF from patients with acute bacterial meningitis was 38.6 pg/mL, with only 9 of these 17 patients showing detectable VEGF levels in CSF. The VEGF indices in patients with bacterial meningitis were significantly lower than in tumor patients with CM (<22.8 versus >62.3), suggesting that the proportion of intrathecally produced VEGF is much higher in patients with CM as compared with patients with bacterial meningitis. Patients without neoplastic or infectious neurologic disorders consistently showed VEGF levels in CSF below the assay detection limit of 25 pg/mL. Immunohistochemistry revealed strong cytoplasmic staining for VEGF in a metastatic lesion from breast cancer infiltrating the meninges. CONCLUSION: In patients with carcinomatous meningitis, significant amounts of VEGF are released into CSF. This study yields preliminary evidence that VEGF in CSF may be a useful biologic marker for both the diagnosis and evaluation of treatment response in carcinomatous meningitis.