Brain natriuretic peptide is associated with worsening and mortality in acute stroke patients but adds no prognostic value to clinical predictors of outcome

BACKGROUND

At the present time, the determination of the outcome of stroke patients is based on the analysis of clinical and neuroimaging data. The use of prognostic blood biomarkers could aid in decision-making processes, e.g. admitting patients to specialized stroke units. Although the prognostic role of natriuretic peptides has been studied in heart failure and coronary diseases, the value of brain natriuretic peptide (BNP) is less known within the field of strokes.

OBJECTIVE

We aimed to study the relationship between plasma levels of BNP and acute neurological worsening or mortality after stroke in a large cohort of patients (investigating both ischemic and hemorrhagic disease).

METHODS

Consecutive stroke patients (ischemic and hemorrhagic) admitted to the Stroke Unit of our University Hospital within 24 h of the onset of symptoms were included. Stroke severity was assessed according to the National Institutes of Health Stroke Scale (NIHSS) at admission and at discharge. Neurological worsening was defined as an increase of 4 or more points in the NIHSS score or death during the patient's stay at the Stroke Unit. Blood samples were drawn upon admission to measure plasma levels of BNP (Biosite Inc., San Diego, Calif., USA). Statistical analysis was performed using SPSS 15.0 and R software.

RESULTS

Altogether, 896 patients were included in the study. BNP plasma levels were higher among patients who deteriorated the most over time (n = 112; 90.5 vs. 61.2 ng/l; p = 0.006) or died (n = 83; 118.2 vs. 60.9 ng/l; p < 0.001). Multivariate logistic regression analysis indicated that plasma BNP level was an independent predictor of neurological worsening [BNP >56.7 ng/l; odds ratio (OR) = 1.64; p = 0.04] and death after stroke (BNP >65.3 ng/l; OR = 1.97; p = 0.034). Adding BNP level to other well-known clinical predictors of bad outcome did not significantly increase the predictive value.

CONCLUSIONS

Plasma levels of BNP measured during the acute phase of stroke are associated both with early neurological worsening and mortality. However, this biological information does not supply prognostic information which would add to clinical variables, which limits its use as a biomarker. Further investigation and systematic reviews are needed to clarify the role of natriuretic peptides in stroke outcome.

Prostate carcinoma metastatic to the skin as an extrammamary Paget's disease

AIM

The current paper describes a case of prostatic adenocarcinoma metastatic to the skin presenting as an extrammamary Paget's disease, a very rare and poorly characterised morphological entity. We report a case of prostatic carcinoma metastatic to skin showing a pattern of extramammary Paget's disease which has not been clearly illustrated in the literature Case presentation: A 63 year-old man with prostatic adenocarcinoma developed cutaneous metastases after 16 years. The inguinal metastases were sessile and 'keratotic.' The tumour displayed solid, glandular areas as well as a polypoid region suggestive of extramammary Paget's disease were identified.

DISCUSSION AND CONCLUSIONS

We review the diagnostic criteria that have led to the correct histopathological diagnosis in this case. A differential diagnosis of the pagetoid spread in the skin and various forms of cutaneous metastases determined by a prostatic adenocarcinoma as well as the role of immunohistochemistry in establishing the prostatic origin are presented in the context of this case. Although, morphologically the cells presented in the skin deposits were not characteristic for adenocarcinoma of prostate, immunohistochemistry for PSA and PSAP suggested a prostatic origin.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1395450057455276.

Opticin exerts its anti-angiogenic activity by regulating extracellular matrix adhesiveness

Opticin is an extracellular matrix glycoprotein that we identified associated with the collagen network of the vitreous humor of the eye. Recently, we discovered that opticin possesses anti-angiogenic activity using a murine oxygen-induced retinopathy model: here, we investigate the underlying mechanism. Using an ex vivo chick chorioallantoic membrane assay, we show that opticin inhibits angiogenesis when stimulated by a range of growth factors. We show that it suppresses capillary morphogenesis, inhibits endothelial invasion, and promotes capillary network regression in three-dimensional matrices of collagen and Matrigel(TM). We then show that opticin binds to collagen and thereby competitively inhibits endothelial cell interactions with collagen via α(1)β(1) and α(2)β(1) integrins, thereby preventing the strong adhesion that is required for proangiogenic signaling via these integrins.

Bisphosphonate-related osteonecrosis of jaw (BRONJ): an anti-angiogenic side-effect?

Bisphosphonates are recommended in the treatment of osteoporosis and some cancers, in which case they prevent the appearance of bone metastasis. The patients taking bisphosphonates are at increased risk of developing bisphosphonate-related osteonecrosis of jaw (BRONJ) which is characterised by the presence of an un-healing wound after dental surgery. BRONJ might represent an anti-angiogenic side effect. However, the real number of patients with BRONJ might be higher than currently recorded. Considering the differential diagnosis which includes various primary and secondary cancers, a correct histopathological diagnosis is very important. The morphological criteria for diagnosis of BRONJ are highlighted in this material.

Early atherosclerotic plaques show evidence of infection by Chlamydia pneumoniae

Chlamydia pneumoniae (Cpn) could play an important role in the development of atherosclerosis. Cpn interferes with HIF-1alpha regulation in infected host cells during intracellular replication in hypoxia. We obtained carotid artery specimens with low (n=38), high (n=25) levels of stenosis and 10 middle cerebral arteries. Fifty eight percent of the carotids with low levels of stenosis showed evidence of the viable organism. Ninety one percent of the positive results were derived from pre-atheromatous lesions. Only 12 percent of plaques removed at endarterectomy showed the presence of Cpn DNA. All middle cerebral arteries failed to show evidence of live Chlamydia. Ninety one percent of sera from 22 endarterectomy patients failed to show the presence of Cpn antibodies. Immunohistology of carotid arteries with low levels of stenosis was used to confirm the presence of HIF-1alpha in infected specimens and showed a correlation between the over-expression of HIF-1alpha and Cpn in the plaque (p less than 0.05). Cpn might play an important role in activation and development of the initial stages of atherosclerotic lesions.

Unique vascular protective properties of natural products: supplements or future main-line drugs with significant anti-atherosclerotic potential?

Natural health products (NHP) which include minerals, vitamins and herbal remedies are not generally considered by medical practitioners as conventional medicines and as such are not frequently prescribed by health centre's as either main-line or supplemental treatments. In the field of cardiovascular medicine, studies have shown that typically, less than half of patients suffering from coronary syndromes chose to take any form of NHP supplement and these products are rarely recommended by their medical practitioner. Vascular/endothelial cell damage is a key instigator of coronary arterial plaque development which often culminates in thrombosis and myocardial infarction (MI). Current treatment for patients known to be at risk of primary or secondary (MI) includes lipid lowering statins, anti-clotting agents (e.g. tissue plasminogen activator; tPA) and drugs for stabilization of blood pressure such as beta-blockers. However, evidence has been building which suggests that components of at least several NHP (e.g. aged garlic extract (AGExt), resveratrol and green tea extracts (GTE)) may have significant vascular protective effects through reduction of oxidative stress, lowering of blood pressure, reduction in platelet aggregation, vasodilation and inhibition of abnormal angiogenesis. Therefore, in this review we will discuss in detail the potential of these substances (chosen on the basis of their potency and complimentarity) as anti-atherosclerotic agents and the justification for their consideration as main-line additional supplements or prescriptions.

Abstract 181: Common Angiogenic Signalling Pathways Induced by Monomeric c-Reactive Protein and FGF-2 Through Phosphatidylinositol 3-kinase

Angiogenesis is the process of new blood vessel growth from pre-existing vascular structures. The new vessels from atherosclerotic lesions may be a focus of instability, since they facilitate the infiltration of inflammatory cells and due to their tendency to leak, they may produce haemorrhagic complications. Pentameric C-reactive protein (CRP), a strong marker of inflammation, is a risk factor for cardiovascular diseases with a direct role in the development of atherosclerotic lesions. In hypoxic tissue damage, CRP dissociates irreversibly into monomeric CRP (mCRP), which was previously demonstrated to be pro-angiogenic on bovine aortic endothelial cells (BAEC). Our main study was to examine the vessel forming capability of CRP in the presence of other angiogenic factors known to be present in the micro-environment of unstable plaques with immature vasculature. Here we studied the effects of mCRP in presence or absence of FGF-2 on BAEC proliferation, migration, tube formation in Matrigel and on the vascular remodelling using spheroids, a tri-dimensional system of endothelial cell culture embedded in collagen gel. A significant synergic effect of mCRP combined with FGF-2 was observed in all angiogenesis assays used, compared to the effect of mCRP or FGF-2 alone. Using the spheroids, both mCRP and FGF-2 stimulated the length of sprouts with endothelial cells more dispersed giving an aspect of thin structures. For a better understanding of the molecular mechanisms involved, the signalling pathways were investigated by Western blotting and all the assays were performed in the presence or absence of pharmacological inhibitors of MAPK (PD98059), γ-secretase (DAPT inhibitor) and phosphatidylinositol 3-kinase (PI3K) pathways (LY294002). We showed mCRP-induced endothelial cell proliferation, migration and tube formation required activation of the PI3K pathway. MAPK activation was essential in mCRP-induced cell proliferation and differentiation (tube formation and sprouting from the core of spheroids) and γ-secretase activity was required for mCRP-induced tube formation only. For its pro-angiogenic activity, FGF-2 required all of these key pathways with the exception that γ-secretase activity was not associated with FGF-2-induced cell migration. In all assays including the over-expression of phospho-ERK, the synergistic pro-angiogenic effect of mCRP added to FGF-2 was completely inhibited by LY294002. Thus, mCRP and FGF-2 have a common signalling pathway through PI3K and an eventual deregulation of their pro-angiogenic effects due to an excessive inflammation inducing a hyper-vascularisation which could contribute to formation of unstable plaque with haemorrhagic risk, and therefore, might be prevented by targeting the key proteins of the PI3K pathway.

Abstract 2387: Modulation Of P35/cyclin-dependent Kinase 5 Signaling Rectifies Defective Human Brain Endothelial Cell Migration Produced By In Vitro Simulation Of Ischemic Stroke

Uncontrolled activation of calcium-sensitive calpain pathways induces neuronal damage during ischemic stroke. Vascular remodelling plays a critical role in tissue recovery. The main molecular events underpinning angiogenesis in stroke are still imprecise. Recently, we highlighted a novel non-neuronal role of the cyclin-dependent kinase (Cdk)-5 operating through p35 activator, which modulates in vitro brain angiogenesis. Cdk5 activators p35 and p25 were recently shown to be involved in neuronal protection (p35) or death (p25) after brain ischemia. However, the impact of p35/Cdk5 on angiogenesis during hypoxic injury remains unclear. Here, using the calpain inhibitor MDL28170 and GFP-Cdk5 wild type (wt) or kinase mutant (D144N) transfectants in an in vitro model of stroke, we tested the hypothesis that activation of p35/Cdk5 pathway may positively modulate angiogenesis during hypoxia. Human brain microvascular endothelial cells (hCMEC/D3) were treated (24h) with MDL28170 (10μM) under conditions of hypoxia (1%O 2 ) or normoxia. Angiogenesis was investigated by wound-healing assay and capillary-tube formation on matrigel, using Cell-IQ® Imaging system (Chip-Man Technologies Ltd). Cell viability was evaluated by assay of MTT proliferation, propidium iodide nuclear inclusion (nPI) and heat shock protein 70 (Hsp70) level. p35, Cdk5 and activated pY(15)Cdk5 intracellular localization were analyzed by confocal microscopy. Protein levels were estimated by western blot. Inhibition of calpain activity increased angiogenesis (p<0.01), augmenting p35 protein levels (30%). Hypoxia induced cell stress, as evidenced by increased Hsp70 (0.8 ±0.02 vs 0.5±0.01, ratio on GAPDH optical density) and nPIs, and hampered cell migration and tube formation (p<0.01). This was associated with reduced p35 (56%, ratio on GAPDH optical density) contents. Blocking Cdk5 activity with D144N transfectant reduced migration (p<0.05). Cdk5 (wt) overexpression enhanced migration, which was further augmented in hypoxia (p<0.05). Hypoxia impaired reorganization of the cytoskeleton and reduced p35/actin co-localization, without affecting the distribution of Cdk5 or pY(15)Cdk5 in association with actin filaments and focal tips. MDL28170 significantly reversed the effects of hypoxia on cell migration and p35 localization, suggesting a role of p35 in cytoskeleton stability. MDL28170 further increased cell migration in Cdk5(wt) or D144N either in hypoxia or normoxia, and Cdk5 protein levels in hypoxia (0.2 ±0.01 vs 0.18±0.01, ratio on GAPDH optical density), implying that increased p35 may be protective during stroke. In conclusion, our data suggest that p35/Cdk5 signaling supports angiogenesis in stroke. p35 may be a signalling intermediate, involved in cytoskeleton organization and cell dynamics during angiogenesis.

Abstract 2330: Citicoline Is A Strong Pro-angiogenic Molecule And Protects Brain Endothelial Cells From Apoptosis After Stroke

Background and purposes - Citicoline is neuroprotective agent used in stroke patients. Citicoline induces angiogenesis i n vitro ; however, the molecular mechanisms induced by citicoline have not been fully investigated. The present study was designed to investigate the key signalling mechanisms through which citicoline modulates angiogenesis-associated with stroke recovery.

Methods - In vitro angiogenesis assays: migration (Bodyen chamber, a chemotaxis assay and wound recovery), proliferation and differentiation into tube-like structures in Matrigel TM as well as spheroid development assays were carried out using human brain microvessel endothelial cells (HBMECs). Western blotting was performed on the protein extraction from HBMEC stimulated with citicoline. Citicoline signalling pathway was studied using a phospho-protein screening array performed by Kinexus. A Staurosporin/calcium ionophore-induced apoptosis assay was performed by seeding HBMEC on the glass coverslips. Cells were pre-incubated with citicoline and the apoptosis was induced by addition of the ionophore or staurosporin. Cells were examined by microscoy and/or stained using propidium iodide and Hoechst stain solution and then counted under fluorescence microscope. Transient MCAO was carried out on Sprague Dawley rats (n=4 per group) with and without citicoline treatment (1000mg/Kg) applied at the time of occlusion and subsequently every 3 days until euthanasia (21 days). Vascularity of the stroke-affected regions was examined with antibodies recognising the microvessels (CD34) and active cells (CD105).

Results - Citicoline presented no mitogenic and chemotactic effects on HBMEC; however, it significantly increased wound recovery, the formation of tube-like structures in Matrigel TM -with a stronger effect than FGF-2, and enhanced spheroid development and sprouting. Citicoline induced the expression of ERK-1/2, known to be involved in last step of signalling pathways of angiogenesis. Kinexus results showed an over-expression of ASK-1, HER2, IRS-1 and Jun and inhibition of Hsp27, Integrin alpha4, MEK1 (MAP2K1) and Histone H2B proteins. Knock-down of IRS-1 with targeted siRNA inhibited the pro-angiogenic effects (sprouting and tube-formation) of citicoline in HBMECs. The percentage of surviving cells was higher in the presence of citicoline after inducing apoptosis. Histology of infarcted regions showed that citicoline significantly increased the numbers of new active (CD105-positive) microvessels.

Conclusion - The findings demonstrate both a pro-angiogenic and protective effect of citicoline on HBMECs in vitro and following MCAO in vitro. Additionally, this molecule may play a key role in the modulation of angiogenesis thereby and ultimately, improving tissue function, revascularisation and neuronal survival after ischaemic stroke.

Mechanisms of cardioprotective effect of aged garlic extract against Doxorubicin-induced cardiotoxicity

Aged garlic has been extensively studied and has been shown to have a number of medicinal properties, including immunomodulatory, hepatoprotective, antimutagenic, anticarcinogenic, and antioxidant effects. The objective of this study was to investigate the mechanisms of the cardioprotective effect of aged garlic extract (AGE), a widely used herbal medicine with potent antioxidant activity, against doxorubicin-induced cardiotoxicity. Moreover, the study investigated if the cardioprotective effect of AGE might be at the expense of the antitumor effect of the anticancer drug doxorubicin (DOX). Primary cultured neonatal rat cardiac myocytes were treated with DOX, AGE, and their combination for 24 hours. DOX increased p53 and caspase 3 activity-induced apoptotic cell death, whereas AGE pretreatment suppressed the action of DOX. AGE pretreatment did not interfere with the cytotoxic activity of DOX, but it increased the DOX uptake into tumor cells and increased the long term survivors of tumor-bearing mice from 30% to 70%. In conclusion, DOX impairs viability of cardiac myocytes, at least partially by activating the p53-mediated apoptotic signaling. AGE can effectively and extensively counteract this action of DOX and may potentially protect the heart from severe toxicity of DOX. At the same time, AGE did not interfere with antitumor activity of DOX.

Antiglycation and antioxidant properties of soy sauces

Diabetes-induced hyperglycemia increases formation of advanced glycation end products (AGEs) and metal-catalyzed production of free radicals. This study compared the antioxidant capacities of dark and light soy sauces of different brands and investigated their abilities to inhibit AGEs and whether their mechanism of action was pre- or post-Amadori or involved chelation of transition metals. The antioxidant capacities of soy sauces were compared using the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) method and by measuring their total phenolic contents. Model proteins (lysozyme, albumin) were glycated using fructose with or without soy sauces with subsequent analysis of cross-linked AGEs by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The effect of soy sauces on pre- and post-Amadori inhibition of AGEs was investigated by measuring fructosamine and AGEs following reincubation of ribose-glycated (ribated) lysozyme, respectively. Dark soy sauces had higher antioxidant capacities and phenolic content and were more effective inhibitors of post-Amadori-derived cross-linked AGEs. However, light soy sauces were more effective at inhibiting fructosamine and had more potent metal chelation properties. This study reports the antiglycation properties of soy sauces, but further studies are required to determine the constituents responsible for this effect and whether soy sauce consumption can reduce oxidative stress and AGEs in diabetic subjects.

Nanotechnology for the treatment of coronary in stent restenosis: a clinical perspective

Coronary in stent restenosis remains a significant limitation to the long term efficacy of coronary artery stent placement. In this review the authors review the pathophysiology of coronary in stent restenosis, together with an overview of the current treatment modalities. The potential clinical utility of nanotechnology is also reviewed.The first human safety trial of systemic nanoparticle paclitaxel (nab-paclitaxel) for in stent restenosis (SNAPIST-I) is discussed. The results showed no significant adverse advents attributable to the nab-paclitaxel at 10 or 30 mg/m2, although moderate neutropenia, sensory neuropathy and mild to moderate reversible alopecia occurred at higher doses. No major adverse cardiac events were recorded at 2 months, whilst at 6 months, 4 target lesions required revascularisation. The investigators concluded therefore that systemic nab-paclitaxel was well tolerated at a dose of <70 mg/m2. To date however, no formal clinical evaluation has been reported as to the clinical utility of nab-paclitaxel, or any of the nano preparations discussed, for the suppression of coronary in stent restenosis.

Synchronous oesophagectomy and hepatic resection for metastatic oesophageal cancer: report of a case

BACKGROUND

Oesophageal cancer with liver metastasis is rare and when diagnosed is usually advanced and surgical management is contraindicated.Method-Results: We report the case of a patient who presented with oesophageal cancer and liver metastasis. The patient received chemotherapy combined with RFA to liver tumour. Subsequently she was subjected to oesophagectomy and liver resection of segment 5 extended into segment 8. Patient underwent adjuvant chemotherapy post-operatively and remains disease-free until now, 29 months after operation.

CONCLUSION

Oesophageal cancer with concomitant liver metastasis is a rare and lethal disease. Multimodal management including surgery may offer prolonged survival in highly selected patients.

Carotid plaque, stroke pathogenesis, and CRP: treatment of ischemic stroke

Inflammation is receiving increased attention as a cause of atherosclerosis and stroke. Several inflammatory biomarkers, and particularly high-sensitivity C-reactive protein (hsCRP), have been identified as likely predictors of the risk of a future stroke. In clinical settings, it has been consistently observed that higher concentrations of CRP are associated with larger brain infarcts, stroke severity, neurologic disability, and future vascular events. However, there is still controversy over the degree of risk conferred by elevated CRP concentrations. Some studies reported that the predictive value of CRP is moderate compared with classical risk factors and is only weakly related to cardiovascular damage after adjustment for traditional cardiovascular risk factors. CRP like many other hemostatic factors is an acute-phase protein and, therefore, it is not always clear whether its association with cerebrovascular disease reflects its contribution to atherothrombosis, its acute-phase condition, or both. Furthermore, the value of single measurements of CRP in patients with concurrent infection or other inflammatory conditions has not been established and reported data should be interpreted cautiously. Several drugs, especially hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), have been demonstrated to reduce hsCRP levels independently of their effects on plasma cholesterol. Recently, emerging therapies have been aimed at the control of blood pressure and inflammation in stroke patients. Whether a reduction of hsCRP levels could be beneficial to stroke patients remains to be clarified, and it is also unclear whether other drugs may be useful to lower hsCRP levels. More studies are needed before hsCRP becomes a routine part of the evaluation of stroke patients. This should also prompt the search for new agents directly blocking CRP actions.

Modified C-reactive protein is expressed by stroke neovessels and is a potent activator of angiogenesis in vitro

Native C-reactive protein (nCRP) is a pentameric oligo-protein and an acute phase reactant whose serum expression is increased in patients with inflammatory disease. We have identified by immunohistochemistry, significant expression of a tissue-binding insoluble modified version or monomeric form of CRP (mCRP) associated with angiogenic microvessels in peri-infarcted regions of patients studied with acute ischaemic stroke. mCRP, but not nCRP was expressed in the cytoplasm and nucleus of damaged neurons. mCRP co-localized with CD105, a marker of angiogenesis in regions of revascularisation. In vitro investigations demonstrated that mCRP was preferentially expressed in human brain microvessel endothelial cells following oxygen-glucose deprivation and mCRP (but not column purified nCRP) associated with the endothelial cell surface, and was angiogenic to vascular endothelial cells, stimulating migration and tube formation in matrigel more strongly than fibroblast growth factor-2. The mechanism of signal transduction was not through the CD16 receptor. Western blotting showed that mCRP stimulated phosphorylation of the key down-stream mitogenic signalling protein ERK1/2. Pharmacological inhibition of ERK1/2 phosphorylation blocked the angiogenic effects of mCRP. We propose that mCRP may contribute to the neovascularization process and because of its abundant presence, be important in modulating angiogenesis in both acute stroke and later during neuro-recovery.

A role for monomeric C-reactive protein in regulation of angiogenesis, endothelial cell inflammation and thrombus formation in cardiovascular/cerebrovascular disease?

Native CRP (nCRP) is a pentameric oligoprotein composed of identical 23 KDa subunits which can be irreversibly dissociated to form free subunits or monomeric CRP (mCRP). mCRP has a reduced aqueous solubility and a tendency to aggregate into matrix-like lattices in various tissues, in particular, blood vessel walls. A dramatic increase in expression of mCRP occurs in angiogenic blood vessels derived from stroked brain regions, atherosclerotic arteries and active vessels from other angiogenic diseases such as Alzheimer's. Furthermore, mCRP unlike the native molecule is highly angiogenic to vascular endothelial cells in vitro and therefore might impact on the processes of vascularization and re-modelling thus affecting tissue survival and development. In this mini-review, we will discuss the differences in the biological properties between nCRP and mCRP. We will provide a brief historical background to the importance of nCRP as a biomarker for cardiovascular disease. We will explain the mechanisms of conversion of nCRP to its monomeric form and describe evidence for the role of mCRP in modulation of endothelial cell activation, promotion of inflammatory status and thrombus formation in cardio/cerebrovascular disease. Finally, we will provide evidence for the accumulation of mCRP in angiogenic microvessels from diseased tissue, and demonstrate its highly pro-angiogenic capabilities. The discovery of the existence of this tissue-associated, highly angiogenic monomeric form of CRP capable of cellular binding and intra-cellular signal transduction activation may help in our understanding of the processes responsible for modulation of angiogenesis and inflammation in disease.

Oligosaccharides of hyaluronan induce angiogenesis through distinct CD44 and RHAMM-mediated signalling pathways involving Cdc2 and gamma-adducin

We used short-interfering RNA (siRNA) to knockdown the hyaluronan (HA) receptors CD44 and the receptor for hyaluronan-mediated motility (RHAMM) in vascular endothelial cells to investigate their role in angiogenesis. We showed that CD44 and RHAMM single knockdown inhibited low molecular weight hyaluronan (o-HA)-induced endothelial cell tube formation in Matrigel, but no change in the control, epidermal growth factor-induced tube formation was observed. Using a Kinexus phosphoprotein array and confirmational Western blotting we were able to show a differential effect on HA-induced protein expression after CD44 and RHAMM knockdown. CD44 knockdown abolished o-HA-induced membrane phospho-protein kinase C-alpha (PKC-alpha) and down-stream phospho-gamma-adducin expression. Using the PKC inhibitor Go6976, we demonstrated the involvement of PKC-alpha and gamma-adducin in o-HA-induced tube formation, whilst o-HA-induced enzymatic activity of MMP9 was also reduced. This suggests that endothelial tube formation involves activation of MMP9 via PKC-alpha. Furthermore, the involvement of gamma-adducin in o-HA-induced F-actin cytoskeleton rearrangement was CD44-dependent and the reduction of CD44 expression lead to a change in endothelial cell morphology. Both RHAMM and CD44 knockdown completely inhibited o-HA-induced Cdc2 (Cdk1) phosphorylation suggesting a possible involvement in cell cycle control. Although CD44 and RHAMM are both involved in o-HA-induced endothelial tube formation in Matrigel, they mediate distinct angiogenic signalling pathway and for the first time we demonstrated the specific involvement of gamma-adducin in CD44/o-HA-induced endothelial tube formation. The data presented here extend our understanding of key stages of the processes of o-HA-induced angiogenesis which may have relevance to tumour progression.

Combining nanotechnology with current biomedical knowledge for the vascular imaging and treatment of atherosclerosis

Activation of vasa vasorum (the microvessels supplying the major arteries) at specific sites in the adventitia initiates their proliferation or 'angiogenesis' concomitant with development of atherosclerotic plaques. Haemorrhagic, leaky blood vessels from unstable plaques proliferate abnormally, are of relatively large calibre but are immature neovessels poorly invested with smooth muscle cells and possess structural weaknesses which may contribute to instability of the plaque by facilitation of inflammatory cell infiltration and haemorrhagic complications. Weak neovascular beds in plaque intima as well as activated adventitial blood vessels are potential targets for molecular imaging and targeted drug therapy, however, the majority of tested, currently available imaging and therapeutic agents have been unsuccessful because of their limited capacity to reach and remain stably within the target tissue or cells in vivo. Nanoparticle technology together with magnetic resonance imaging has allowed the possibility of imaging of neovessels in coronary or carotid plaques, and infusion of nanoparticle suspensions using infusion catheters or implant-based drug delivery represents a novel and potentially much more efficient option for treatment. This review will describe the importance of angiogenesis in mediation of plaque growth and development of plaque instability and go on to investigate the possibility of future design of superparamagnetic/perfluorocarbon-derived nanoparticles for imaging of the vasculature in this disease or which could be directed to the adventitial vasa vasorum or indeed intimal microvessels and which can release active payloads directed against primary key external mitogens and intracellular signalling molecules in endothelial cells responsible for their activation with a view to inhibition of angiogenesis.