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Objective: AIDS-related lymphomas are high grade and aggressively metastatic with poor prognosis. Lymphangiogenesis is essential in supporting proliferation and survival of lymphoma, as well as tumor dissemination. Data suggest that aberrant lymphangiogenesis relies on action of HIV-1 proteins rather than on a direct effect of the virus itself. HIV-1 matrix protein p17 was found to accumulate and persist in lymph nodes of patients even under highly active antiretroviral therapy. Because p17 was recently found to exert a potent proangiogenic activity by interacting with chemokine (C-X-C motif) receptors 1 and 2, we tested the prolymphangiogenic activity of the viral protein., Approach and Results: Human primary lymph node-derived lymphatic endothelial cells were used to perform capillary-like structure formation, wound healing, spheroids, and Western blot assays after stimulation with or without p17. Here, we show that p17 promotes lymphangiogenesis by binding to chemokine (C-X-C motif) receptor-1 and chemokine (C-X-C motif) receptor-2 expressed on lymph node-derived lymphatic endothelial cells and activating the Akt/extracellular signal-regulated kinase signaling pathway. In particular, it was found to induce capillary-like structure formation, sprout formation from spheroids, and increase lymph node-derived lymphatic endothelial cells motility. The p17 lymphangiogenic activity was, in part, sustained by activation of the endothelin-1/endothelin receptor B axis. A Matrigel plug assay showed that p17 was able to promote the outgrowth of lymphatic vessels in vivo, demonstrating that p17 directly regulates lymphatic vessel formation., Conclusions: Our results suggest that p17 may generate a prolymphangiogenic microenvironment and plays a role in predisposing the lymph node to lymphoma growth and metastasis. This finding offers new opportunities to identify treatment strategies in combating AIDS-related lymphomas.

Background and Purpose: Early hematoma growth (EHG) occurs in about one third of patients with spontaneous intracerebral hemorrhage. The main aim of this study was to investigate the potential of plasma C-reactive protein (CRP) for predicting EHG after acute spontaneous intracerebral hemorrhage., Methods: Plasma CRP was measured within 6 hours of onset (median, 120 minutes) in 399 patients with primary or vitamin K antagonist-associated spontaneous intracerebral hemorrhage and without recent infection. Computed tomography brain scans were performed at baseline and repeated within 24 hours (median, 22 hours). The primary outcome was EHG, defined as absolute growth>12.5 cm3 or relative growth>33%. Secondary outcomes included early neurological worsening (ENW) using the Glasgow Coma Scale and 30-day mortality. Multivariable regression analyses were used to evaluate associations of CRP concentration and outcomes. Kaplan-Meier analysis was used for survival., Results: EHG occurred in 25.8%, ENW in 19.3%, and mortality was 31.8% at 30 days. Thirty-day mortality was significantly higher in patients with ENW (hazard ratio, 3.21; 95% confidence interval, 2.00-5.17; P<0.0001) and in patients with EHG (hazard ratio, 2.13; 95% confidence interval, 1.42-3.18; P<0.0001, log-rank test). Median CRP was 12 mg/L (interquartile range, 10-17) in the EHG group and 7 mg/L (interquartile range, 4-12.1) in those without EHG (P<0.0001). In multivariable analyses, plasma CRP>10 mg/L independently predicted EHG (odds ratio, 4.71; 95% confidence interval, 2.75-8.06; P<0.0001) and ENW (odds ratio, 2.70; 95% confidence interval, 1.50-4.84; P=0.0009)., Conclusions: CRP>10 mg/L is independently predictive of EHG and ENW, both of which are associated with increased mortality. Inflammation may be important in contributing to EHG and warrants further investigation.

Objectives: We examined the C-reactive protein (CRP) response after spontaneous intracerebral hemorrhage (sICH) and its relationship to outcome. We additionally characterized early brain localization of CRP., Methods: In this prospective, multicenter, international, collaborative, longitudinal study with cross-sectional immunohistochemical analysis of brain tissue, 223 patients (M/F: 132/91) were recruited during the 2010 calendar year. CRP was evaluated at admission (median 93 minutes from symptom onset), 24 hours, 48 hours, and 72 hours after sICH. Brains of 5 subjects with sICH were compared to brains of 2 aged controls without evidence of brain pathology and 7 patients with ischemic stroke. Plasma CRP was measured over 72 hours following sICH and its relationship to 30-day mortality and functional outcome at 30 days (Glasgow Outcome Scale) was determined. CRP immunostaining patterns were analyzed in samples of sICH autopsy brains., Results: Plasma CRP increased over the 48 hours from admission and was significantly (p < 0.001) related to hematoma volume at later time points. The predictive utility of CRP for morbidity and mortality were maintained when adjusted for other risk factors and improved at 48 hours and 72 hours when compared with admission values. Although an early CRP localization was present in both ischemic and hemorrhagic lesions, an intense and diffuse neuropil staining was only present in sICH patients and particularly evident proximal to the hemorrhagic areas., Conclusions: Plasma CRP production increases markedly over the 48 hours to 72 hours period following sICH and is related to outcome. CRP is also present in large amounts around the hemorrhagic lesion and within neurons and glia of patients who died within 12 hours of sICH.

Objective: We studied the impact of native (natCRP) and modified CRP (mCRP) isoforms on platelet adhesion and thrombus growth under arterial flow., Methods and Results: Blood was perfused over type I collagen at a wall shear rate of 1500 s(-1), and platelet deposition and thrombus growth were evaluated by confocal microscopy. natCRP and mCRP were either incubated with blood before perfusion experiments or immobilized in the collagen surface and exposed to flowing blood. mCRP significantly increased platelet adhesion and thrombus growth when directly incubated with blood and when immobilized on a collagen surface (P<0.05). In contrast, natCRP did not exert any effect. Confocal immunohistochemistry revealed the presence of CRP on the surface of adhered platelets and within the thrombus and showed an upregulation of P-selectin and CD36 in effluent platelets preincubated with mCRP (P<0.05). Flow cytometry analysis of agonist-induced platelet activation demonstrated that mCRP, but not natCRP, significantly increased platelet surface P-selectin (P<0.05) without modifying CD63 and PAC-1., Conclusions: Our data indicate that whereas serum natCRP may not affect thrombus growth, mCRP displays a prothrombotic phenotype enhancing not only platelet deposition, but also thrombus growth under arterial flow conditions.

Hyaluronic acid, a major component of the brain extracellular matrix, is a regulator of angiogenesis, cell differentiation and migration. We used the rat middle cerebral artery occlusion model to show hyaluronan accumulation in stroke-affected areas. Using reverse transcription-polymerase chain reaction and Western blotting we showed up-regulation of hyaluronidase-1 and 2 between 1 h and 21 days after stroke. Hyaluronidase-1 was up-regulated earlier than hyaluronidase-2. The hyaladherins, receptor for hyaluronan-mediated motility and CD44 were also increased after stroke. Using immunohistochemistry, we showed association of hyaluronidases 1/2 and hyaladherins with neurons in the infarcted and peri-infarcted regions and hyaluronidase-1 with microvessels. Hyaluronan synthesis and degradation in the stroke hemisphere might have an impact on neuronal survival, angiogenesis and general tissue remodelling after stroke.

Background and Purpose: There is growing evidence suggesting that C-reactive protein (CRP) is an effecter molecule able to induce and promote atherothrombosis. The presence of CRP in atherosclerotic plaques may reflect local production or infiltration from circulating CRP increased in general inflammatory responses. Our aim was to analyze the presence of CRP in human advanced carotid artery plaques with differential anatomo-pathological characteristics and to assess local expression of CRP and other proinflammatory genes in these lesions., Methods: Human carotid artery specimens from 38 patients undergoing scheduled endarterectomy were classified into 3 groups: ulcerated (noncomplicated) (UNC, n=19), fibrous (F, n=12) and ulcerated (complicated/hemorrhagic) plaques (UC, n=7). The presence of CRP was evaluated by immunohistochemistry, and plasma samples were screened for circulating high-sensitivity C-reactive protein. TaqMan Low-density Arrays were used for study of genes related to inflammation (CRP, interleukin-6, macrophage colony-stimulating factor-1, monocyte chemotactic protein-1, cyclooxygenase-2)., Results: CRP mRNA levels were predominantly detected in UNC-high risk plaques but not in UC (P=0.001). UNC also exhibit the highest expression levels of other genes involved in the inflammatory responses: cyclooxygenase-2 (P<0.005 versus F and versus UC), IL-6 (P<0.005 versus F and versus UC) and monocyte chemoattractant protein-1 (P<0.01 versus F and versus UC). Plaque CRP mRNA levels correlated with immunohistochemical findings but were independent of plasma high-sensitivity CRP. In UNC plaques endothelial cells and inflammatory cells were strongly positive for CRP around areas of newly formed microvessels., Conclusions: In human high-risk carotid artery plaques (UNC) CRP expression reflects an active proinflammatory stage. Local synthesis of CRP could be involved in plaque neovascularization and increased risk of hemorrhagic transformation.

Penumbra tissue becomes highly angiogenic after ischaemic stroke in man, and the re-establishment of a functional vasculature might be beneficial to patients. Unilateral ischaemia was induced in male Sprague-Dawley rats by permanent occlusion of the distal left middle cerebral artery (MCAO). Animals with stroke were kept alive for 1, 7, 14, 21 or 28 days after which time they were terminally anaesthetized. Vascular casts of infarcted areas, analyzed by scanning electron microscopy demonstrated that radially arranged neocortical arterioles and venules lost their regular patterns within one day of occlusion, and soon afterwards started to form a very dense network of anastomosing microvessels. At 1 week, vascular budding was visible at many sites. The smallest microvessels (4-10 microm) formed connections with the surrounding proliferating vessels similar to those in the normal brain. Survival of microvascular endothelial cells (ECs) was studied by double labeling of tissue sections using immunohistochemistry and antibodies to caspase-3, and TUNEL staining for apoptotic cells. ECs demonstrated intensive staining for caspase-3 and also staining by TUNEL, particularly near the infarct border, 14 days post-MCAO. These data support the hypothesis that growing blood vessels in ischaemic tissue form new connections, the pattern of which is similar to that in normal rat brain, but different to those formed in growing tumours. This normal growth pattern might be essential in future therapies involving induction of vascularization and neuroprotection to enhance long-term survival of the penumbra.

We examined expression of vascular endothelial growth factor (VEGF), phosphorylation of mitogen activated protein kinase (MAP) kinase (ERK1 and ERK2) and tyrosine phosphorylation in 19 patients (aged 58-90 years; mean 75) who died 1-44 days after acute ischaemic stroke. In the grey matter penumbra, 13 of 19 patients showed an increase in MAP kinase tyrosine phosphorylation (ERK1; 2.0- to 8-fold, ERK2; 2.2- to 11-fold) compared with normal contralateral tissue. In almost all cases, ERK-2 phosphorylation was higher than ERK1. Of these 13 patients, 11 also showed a general increase in tyrosine kinase phosphorylation, and eight expressed increased levels of VEGF protein (2.5- to 5-fold). In tissue examined directly from the infarct core, activation of the above proteins was not observed in the, majority of patients. In the white matter, seven of 19 patients (penumbra), and nine of 19 patients (stroke) had an increase in MAP kinase tyrosine phosphorylation (ERK1; 2.0- to 4.6-fold and ERK-2; 2.3- to 5.4-fold respectively) compared with normal contralateral tissue. There was no relationship between activation of MAP kinase and expression of VEGF. Examination of phosphorylated MAP kinase by immunohistochemistry revealed an increase in immunoreactivity in neurones, astroglial cells, reactive microglia and endothelial cells in areas surrounding infarcts, especially in areas with the highest density of microvessels. In conclusion, chronic activation of tyrosine phosphorylated events, in particular redistribution and phosphorylation of MAP kinase (ERK1/ERK2) occurs consistently in the grey matter penumbra of brain tissue following ischaemic stroke, and may be associated with increase in expression of VEGF. These signal transduction events could be important determinants of the extent of neuronal survival and/or angiogenic activity in the recovering brain tissue.

Background and Purpose: Both vascular endothelial growth factor (VEGF) and transforming growth factor-beta1 (TGF-beta1) are expressed in higher than normal concentrations in the penumbra of patients after ischemic stroke. Because both cytokines are central to the processes of angiogenesis, tissue inflammation, and fibrosis, we performed serial measurements of these cytokines in patients with cerebral infarction and determined their relationship to stroke etiology and volume., Methods: We serially (at days 0, 1, 3, 7, and 14) measured the serum levels of VEGF and active TGF-beta1 in 29 patients with acute ischemic stroke. Age-matched healthy subjects (n=26) were used as controls., Results: Expression of VEGF was significantly increased in the majority of patients after acute stroke at each of the time points compared with normal controls. Highest expression occurred at day 7 (588+/-121 pg/mL; P=0.005), and it remained significantly elevated at 14 days after stroke. Expression of VEGF correlated with infarct volume, clinical disability (Scandinavian Stroke Scale), and peripheral leukocytosis and was significantly higher in patients with atherothrombotic large-vessel disease and ischemic heart disease (P<0.05 in all cases). In contrast, expression of active TGF-beta1 was not significantly different from control patients at any of the measured time points. When the mean concentration of TGF-beta1 from each patient (pooled time points) was compared with the control mean, a significant increase was found in only 2 patients, whereas levels decreased in 12 patients (P<0.05). There was no correlation between circulating active TGF-beta1 and VEGF expression, leukocytosis, stroke subtype, or patient disability as assessed by Scandinavian Stroke Scale score., Conclusions: VEGF but not TGF-beta1 showed a dramatic increase in serum of stroke patients. Correlation between stroke severity and VEGF concentration suggests it could be involved in the subsequent repair processes resulting in partial recovery after stroke. Correlation between VEGF expression and peripheral leukocytosis suggests that these changes may also reflect the immunologic status of the patient. VEGF may play an important role in the pathophysiology of acute ischemic stroke and could be of value in future treatment strategies.

Background and Purpose: Growth factors control two important processes in infarcted tissue, ie, angiogenesis and gliosis. We recently reported that transforming growth factor-beta1 (TGF-beta1) might be involved in angiogenesis after ischemic stroke in humans; here we present data of an extensive study on platelet-derived growth factor (PDGF) and its receptors., Methods: We studied brain samples from patients who suffered from ischemic stroke for the expression of mRNA encoding PDGF-A, PDGF-B, and PDGF receptors (PDGF-R). Proteins were examined by Western blotting and immunohistochemistry using the antibodies to PDGF-AB, PDGF-BB, PDGF-R alpha, and PDGF-R beta., Results: At the mRNA level, PDGF-A and PDGF-B were expressed mainly in neurons in penumbra. PDGF-R mRNA was strongly expressed in some astrocytes but mainly in type III/IV neurons in infarct and penumbra. The least expression was seen in the contralateral hemisphere (P<.001). In contrast, both PDGF-AB and PDGF-BB immunoreactive products were present in most cell types: PDGF-R alpha and PDGF-R beta mainly on neurons, and PDGF-R beta on some endothelial cells, with less staining of all the isoforms in the contralateral hemisphere. On Western blots, PDGF-AB and -BB were expressed more within white matter than gray matter of infarct/penumbra, whereas both isoforms of receptor were expressed mainly in gray matter compared with contralateral hemisphere. There was no or very weak expression of the receptor in white matter., Conclusions: PDGF proteins are highly expressed in white matter, suggesting that PDGF may exert its function in white matter participating either in regeneration of damaged axons or in glial scar formation. PDGF-BB and its receptor expressed on microvessel endothelial cells might be involved in angiogenesis after stroke. Thus, PDGF is likely to be angiogenic and neuroprotective in stroke.