A multimodality vascular imaging phantom with fiducial markers visible in DSA, CTA, MRA, and ultrasound.

The objective was to design a vascular phantom compatible with digital subtraction angiography, computerized tomography angiography, ultrasound and magnetic resonance angiography (MRA). Fiducial markers were implanted at precise known locations in the phantom to facilitate identification and orientation of plane views from three-dimensional (3-D) reconstructed images. A vascular conduit connected to tubing at the extremities of the phantom ran through an agar-based gel filling it. A vessel wall in latex was included around the conduit to avoid diffusion of contrast agents. Using a lost-material casting technique based on a low melting point metal, geometries of pathological vessels were modeled. During the experimental testing, fiducial markers were detectable in all modalities without distortion. No leak of gadolinium through the vascular wall was observed on MRA after 5 hours. Moreover, no significant deformation of the vascular conduit was noted during the fabrication process (confirmed by microtome slicing along the vessel). The potential use of the phantom for calibration, rescaling, and fusion of 3-D images obtained from the different modalities as well as its use for the evaluation of intra- and inter-modality comparative studies of imaging systems are discussed. In conclusion, the vascular phantom can allow accurate calibration of radiological imaging devices based on x-ray, magnetic resonance and ultrasound and quantitative comparisons of the geometric accuracy of the vessel lumen obtained with each of these methods on a given well defined 3-D geometry.

Maladies vasculaires rares [Rare vascular diseases].

Scarce knowledge of vascular rare diseases, defined by prevalence lower than 1/2000, is accompanied by increased patients mis-management and impaired quality of life. Recent advances in clinical knowledge, molecular biology, and genetic evaluation of certain vascular rare diseases allows designing new management strategies. A tight coordinated collaboration between angiologists and other specialists is therefore necessary to optimize patient's care.

Salvage treatment for venous aneurysm complicating vascular access arteriovenous fistula: use of an exoprosthesis to reinforce the vein after aneurysmorrhaphy.

OBJECTIVES: We report a new salvage technique for treating venous aneurysms (VAs) complicating vascular access arteriovenous fistula (AVF) using externally reinforced venous aneurysmorrhaphy. DESIGN: A retrospective study over a 20-month period from a single centre. PATIENTS: Patients presenting to the vascular surgery department, Bordeaux University Hospital for revision of a vascular access AVF were included. METHODS: Reinforced venous aneurysmorrhaphy consisted in removal of redundant vessel wall followed by reinforcement using an external prosthetic graft. Patency, diameter and flow were assessed by duplex ultrasound at 1, 6 and 12 months after salvage. RESULTS: Thirty-eight eligible patients were identified. Five were excluded because VA was associated with central vein stenosis; the remaining 33 underwent salvage. Indications were rapidly expanding or painful VA in seven cases; VA with frequent bleeding or damaged overlying skin in eight; VA in close relation to a stenosis in two; and VA associated with high-flow rate in 16. Cannulation was attempted after 30 days. Mean follow-up time was 12 S.D. 5 months (range: 4-22). Two repaired AVFs failed. Primary 1-year patency was 93%. No aneurysm or infection occurred. Reduction of high flow was successful in 12 of 16 patients. The remaining four required re-operation. CONCLUSIONS: Reinforced venous aneurysmorrhaphy is effective in controlling venous dilation and achieving patency. Reduction of high-flow rates was not always achieved. Further study is needed to evaluate long-term efficacy of this treatment.

Reduction of choroidal neovascularization in mice by adeno-associated virus-delivered anti-vascular endothelial growth factor short hairpin RNA.

BACKGROUND: Strategies leading to the long-term suppression of inappropriate ocular angiogenesis are required to avoid the need for repetitive monthly injections for treatment of diseases of the eye, such as age-related macular degeneration (AMD). The present study aimed to develop a strategy for the sustained repression of vascular endothelial growth factor (VEGF), which is identified as the key player in exudative AMD. METHODS: We have employed short hairpin (sh)RNAs combined with adeno-associated virus (AAV) delivery to obtain the targeted expression of potent gene-regulatory molecules. Anti-VEGF shRNAs were analyzed in human retinal pigment epithelial (RPE) cells using Renilla luciferase screening. For in vivo delivery of the most potent shRNA, self-complementary AAV vectors were packaged in serotype 8 capsids (scAAV2/8-hU6-sh9). In vivo efficacy was evaluated either by injection of scAAV2/8-hU6-sh9 into murine hind limb muscles or in a laser-induced murine model of choroidal neovascularization (CNV) following scAAV2/8-hU6-sh9 subretinal delivery. RESULTS: Plasmids encoding anti-VEGF shRNAs showed efficient knockdown of human VEGF in RPEs. Intramuscular administration led to localized expression and 91% knockdown of endogenous murine (m)VEGF. Subsequently, the ability of AAV2/8-encoded shRNAs to impair vessel formation was evaluated in the murine model of CNV. In this model, the sizes of the CNV were significantly reduced (up to 48%) following scAAV2/8-hU6-sh9 subretinal delivery. CONCLUSIONS: Using anti-VEGF vectors, we have demonstrated efficient silencing of endogenous mVEGF and showed that subretinal administration of scAAV2/8-hU6-sh9 has the ability to impair vessel formation in an AMD animal model. Thus, AAV-encoded shRNA can be used for the inhibition of neovascularization, leading to the development of sustained anti-VEGF therapy. Copyright © 2012 John Wiley & Sons, Ltd.

Short and longterm ocular vascular effects after intravitreal injection of ranibizumab for neovascular age-related macular degeneration

Purpose: To investigate the effect of the first and repeated intravitreal injections of ranibizumab (1.25mg; 0.05ml) on retrobulbar blood flow velocities in patients with wet age-related macular degeneration (AMD). Methods: This prospective non randomized study included twenty consecutive AMD patients. Time- averaged mean blood flow velocities (BFVs) in the central retinal, temporal posterior ciliary and ophthalmic arteries (CRA, TPCA and OA) were measured by ultrasound imaging before, 2 days and 3 weeks after the first injection of ranibizumab, then 6 months after supplemental monthly injections if required. At each visit, complete ophthalmological examination was performed, including best corrected visual acuity measurement according to ETDRS protocol and OCT. Results: In the treated eyes, ranibizumab injection was followed by a significant improvement in visual acuity (from 44.4 ± 21.7, to 50.9±25.9 (p<0.01) at month 6, and a decrease in mean central macular thickness from 377±115 to 267 ± 74 µm (p<0.001) at month 6. At day 2 mean BFVs decreased by 16% in the CRA and by 20% in TPCA (p<0.001, both), then remained stable. Mean BFVs did not change in OA at the day 2 but decreased at week 3 by 18% (p<0.001). Supplemental injections did not lead to additional effects at month 6. No effect was tabulated in the fellow eye. Conclusions: We report an early decrease in mean BFV in CRA and TPRA following intravitreal injections of ranibizumab corresponding to vasoconstrictive effect of this drug. Decrease in mean BFV in all retrobulbar arteries from the week 3 suggests that ranibizumab proceeds to a local and regional vasoconstrictive and antiangiogenic effects after local diffusion. Thus, ranibizumab could induce an actual hypoperfusion of the treated eye which could correspond to a vascular side effect.

Effets du traitement par CPAP sur la vigilance, la qualité de vie, l'inflammation et la pression artérielle chez les patients apnéiques

Contexte¦Le syndrome d'apnées/hypopnées obstructives du sommeil (SAHOS) est une maladie qui¦touche 4% des hommes et 2% des femmes entre 30 à 60 ans. Les patients touchés par le¦SAHOS ont deux problèmes principaux: premièrement, ils ont davantage de risque de¦développer une maladie cardiovasculaire. Deuxièmement, ils ont une diminution de la qualité¦de vie se présentant principalement sous forme de somnolence diurne et une perte de¦vigilance. Le meilleur traitement à l'heure actuelle est le CPAP (continuous positive airway¦pressure) qui permet de normaliser la respiration nocturne et d'améliorer la qualité du¦sommeil. Les effets favorables du CPAP sur la qualité de vie, la vigilance et l'inflammation¦ont été suggérés par plusieurs études mais restent controversés.¦Objectifs¦Évaluer l'effet de 6 semaines de traitement par CPAP sur la qualité de vie, la vigilance, la¦pression artérielle et l'inflammation (HsCRP).¦Méthodes¦Vingt-neuf patients connus pour un SAHOS ont été inclus dans cette étude. Les critères¦d'exclusions comprenaient une grossesse chez la femme, la présence de facteurs de risque¦cardiovasculaires ou d'une autre pathologie sévère.¦Les patients inclus dans l'étude ont tous été investigués, avant de débuter le traitement par¦CPAP, par un PVT (psychomotor vigilance test), un questionnaire de qualité de vie (SF-36),¦une polysomnographie, un dosage de l'hsCRP et par 2 prises de pression artérielle (avant et¦après la polysomnographie). Après ces examens, le traitement par CPAP a été introduit pour¦six semaines à l'issue desquelles les mêmes examens ont été répétés.¦Résultats¦L'étude montre tout d'abord une amélioration significative des paramètres concernant la¦vigilance : 1/temps de réaction (P = 0.01) et les oublis (P = 0.04). Ensuite, tous les paramètres¦de la santé mentale évalués par le questionnaire SF-36 s'améliorent significativement ainsi¦que le score global de santé physique. L'hsCRP évaluant l'inflammation montre une tendance¦à la diminution (P = 0.07). Quant à la pression artérielle, la pression systolique du soir¦diminue de manière significative et la pression systolique du matin et les deux tensions¦artérielles moyennes calculées montrent une tendance à la diminution.¦Conclusion¦Cette étude montre un effet bénéfique du CPAP chez les patients atteints de SAHOS au niveau¦de la vigilance et de la qualité de vie. Les effets sur la pression artérielle et l'inflammation ne¦sont toutefois pas complètement établis et restent encore sujet à débat.

On the retinal toxicity of intraocular glucocorticoids.

Corticosteroids are hormones involved in many physiological responses such as stress, immune modulation, protein catabolism and water homeostasis. The subfamily of glucocorticoids is used systemically in the treatment of inflammatory diseases or allergic reactions. In the eye, glucocorticoides are used to treat macular edema, inflammation and neovascularization. The most commonly used glucocorticoid is triamcinolone acetonide (TA). The pharmaceutical formulation of TA is not adapted for intravitreal administration but has been selected by ophthalmologists because its very low intraocular solubility provides sustained effect. Visual benefits of intraocular TA do not clearly correlate with morpho-anatomical improvements, suggesting potential toxicity. We therefore studied, non-common, but deleterious effects of glucocorticoids on the retina. We found that the intravitreal administration of TA is beneficial in the treatment of neovascularization because it triggers cell death of endothelial cells of neovessels by a caspase-independent mechanism. However, this treatment is toxic for the retina because it induces a non-apoptotic, caspase-independent cell death related to paraptosis, mostly in the retinal pigmented epithelium cells and the Müller cells.

Thymic stromal lymphopoietin plays divergent roles in murine models of atopic and nonatopic airway inflammation.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) is a cytokine primarily produced by epithelial cells, which has been shown to be a potent inducer of T-helper 2 (Th2)-type responses. However, TSLP has pleiotropic effects upon immune cells, and although extensively studied in the context of atopic asthma, its relevance as a therapeutic target and its role in the pathogenesis of nonatopic asthma remains unknown. We sought to investigate the role of TSLP in atopic, nonatopic and viral-induced exacerbations of pulmonary inflammation. METHODS: Using stringently defined murine models of atopic, nonatopic and virally exacerbated forms of pulmonary inflammation, we compared inflammatory responses of C57BL/6 wild-type (WT) and TSLP receptor-deficient (TSLPR KO) mice. RESULTS: Thymic stromal lymphopoietin receptor (TSLPR) signaling was crucial for the development of atopic asthma. Specifically, TSLPR signaling to lung recruited CD4+ T cells enhanced eosinophilia, goblet cell hyperplasia, and overall inflammation within the airways. In contrast, the absence of TSLPR signaling was associated with strikingly exaggerated pulmonary neutrophilic inflammation in a nonatopic model of airway inflammation. The inflammation was associated with excessive levels of interleukin (IL)-17A in the lungs, indicating that TSLP negatively regulates IL-17A. In addition, in a model of influenza-induced exacerbation of atopic airway inflammation, the absence of TSLPR signaling also led to exaggerated neutrophilic inflammation. CONCLUSION: Thymic stromal lymphopoietin plays divergent roles in the pathogenesis of atopic and nonatopic asthma phenotypes by either enhancing Th2 responses or curtailing T-helper 17 responses. These findings raise important caveats for the design of therapeutic interventions targeting TSLP in asthma.

Physiological ligands of PPARs in inflammation and lipid homeostasis

Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors that are involved in many physiological processes, such as inflammation and energy homeostasis. In general, PPARs must be activated by ligands to stimulate the expression of their target genes. These agonists can be synthetic molecules, such as drugs used to treat hypertriglyceridemia and insulin resistance, or natural physiological ligands, such as fatty acids and eicosanoids. Although recent work has uncovered a surprisingly broad variety of natural molecules capable of activating PPARs, relatively little is known about their mode of action in an in vivo physiological context. The action of physiological ligands in situations of food deprivation and abundance, especially with respect to their intervention in the inflammatory response, and in both lipid homeostasis and inflammation resolution will be reviewed.

Inflammation-induced changes in expression and glycosylation of genetic variants of alpha 1-acid glycoprotein. Studies with human sera, primary cultures of human hepatocytes and transgenic mice.

The relative occurrence of genetic variants of human alpha 1-acid glycoprotein (AGP) in relation to changes in glycosylation was studied in sera of patients with burn injury, media of cytokine-treated primary cultures of human hepatocytes and Hep 3B cells, and sera of transgenic mice expressing the human AGP-A gene. It is concluded (i) that the glycosylation of AGP was not dependent on its genetic expression and (ii) that both the variants determined by the AGP-A gene as well as by the AGP-B/B' genes are increased after inflammation or treatment with interleukins 1 and 6.

Moderate postnatal hyperoxia accelerates lung growth and attenuates pulmonary hypertension in infant rats after exposure to intra-amniotic endotoxin.

To determine the separate and interactive effects of fetal inflammation and neonatal hyperoxia on the developing lung, we hypothesized that: 1) antenatal endotoxin (ETX) causes sustained abnormalities of infant lung structure; and 2) postnatal hyperoxia augments the adverse effects of antenatal ETX on infant lung growth. Escherichia coli ETX or saline (SA) was injected into amniotic sacs in pregnant Sprague-Dawley rats at 20 days of gestation. Pups were delivered 2 days later and raised in room air (RA) or moderate hyperoxia (O₂, 80% O₂ at Denver's altitude, ∼65% O₂ at sea level) from birth through 14 days of age. Heart and lung tissues were harvested for measurements. Intra-amniotic ETX caused right ventricular hypertrophy (RVH) and decreased lung vascular endothelial growth factor (VEGF) and VEGF receptor-2 (VEGFR-2) protein contents at birth. In ETX-exposed rats (ETX-RA), alveolarization and vessel density were decreased, pulmonary vascular wall thickness percentage was increased, and RVH was persistent throughout the study period compared with controls (SA-RA). After antenatal ETX, moderate hyperoxia increased lung VEGF and VEGFR-2 protein contents in ETX-O₂ rats and improved their alveolar and vascular structure and RVH compared with ETX-RA rats. In contrast, severe hyperoxia (≥95% O₂ at Denver's altitude) further reduced lung vessel density after intra-amniotic ETX exposure. We conclude that intra-amniotic ETX induces fetal pulmonary hypertension and causes persistent abnormalities of lung structure with sustained pulmonary hypertension in infant rats. Moreover, moderate postnatal hyperoxia after antenatal ETX restores lung growth and prevents pulmonary hypertension during infancy.

Medroxyprogesterone abrogates the inhibitory effects of estradiol on vascular smooth muscle cells by preventing estradiol metabolism.

Sequential conversion of estradiol (E) to 2/4-hydroxyestradiols and 2-/4-methoxyestradiols (MEs) by CYP450s and catechol-O-methyltransferase, respectively, contributes to the inhibitory effects of E on smooth muscle cells (SMCs) via estrogen receptor-independent mechanisms. Because medroxyprogesterone (MPA) is a substrate for CYP450s, we hypothesized that MPA may abrogate the inhibitory effects of E by competing for CYP450s and inhibiting the formation of 2/4-hydroxyestradiols and MEs. To test this hypothesis, we investigated the effects of E on SMC number, DNA and collagen synthesis, and migration in the presence and absence of MPA. The inhibitory effects of E on cell number, DNA synthesis, collagen synthesis, and SMC migration were significantly abrogated by MPA. For example, E (0.1micromol/L) reduced cell number to 51+/-3.6% of control, and this inhibitory effect was attenuated to 87.5+/-2.9% by MPA (10 nmol/L). Treatment with MPA alone did not alter any SMC parameters, and the abrogatory effects of MPA were not blocked by RU486 (progesterone-receptor antagonist), nor did treatment of SMCs with MPA influence the expression of estrogen receptor-alpha or estrogen receptor-beta. In SMCs and microsomal preparations, MPA inhibited the sequential conversion of E to 2-2/4-hydroxyestradiol and 2-ME. Moreover, as compared with microsomes treated with E alone, 2-ME formation was inhibited when SMCs were incubated with microsomal extracts incubated with E plus MPA. Our findings suggest that the inhibitory actions of MPA on the metabolism of E to 2/4-hydroxyestradiols and MEs may negate the cardiovascular protective actions of estradiol in postmenopausal women receiving estradiol therapy combined with administration of MPA.

Targeting IL-1β and IL-17A driven inflammation during influenza-induced exacerbations of chronic lung inflammation.

For patients with chronic lung diseases, such as chronic obstructive pulmonary disease (COPD), exacerbations are life-threatening events causing acute respiratory distress that can even lead to hospitalization and death. Although a great deal of effort has been put into research of exacerbations and potential treatment options, the exact underlying mechanisms are yet to be deciphered and no therapy that effectively targets the excessive inflammation is available. In this study, we report that interleukin-1β (IL-1β) and interleukin-17A (IL-17A) are key mediators of neutrophilic inflammation in influenza-induced exacerbations of chronic lung inflammation. Using a mouse model of disease, our data shows a role for IL-1β in mediating lung dysfunction, and in driving neutrophilic inflammation during the whole phase of viral infection. We further report a role for IL-17A as a mediator of IL-1β induced neutrophilia at early time points during influenza-induced exacerbations. Blocking of IL-17A or IL-1 resulted in a significant abrogation of neutrophil recruitment to the airways in the initial phase of infection or at the peak of viral replication, respectively. Therefore, IL-17A and IL-1β are potential targets for therapeutic treatment of viral exacerbations of chronic lung inflammation.

Substance P-induced skin inflammation is not modulated by a single dose of sitagliptin in human volunteers.

Substance P (SP), an undecapeptide belonging to the tachykinin family, is released during the activation of sensory nerves, and causes vasodilation, edema and pain through activation of tissular Neurokinin 1 receptors. SP proinflammatory effects are terminated by angiotensin converting enzyme (ACE) and neutral endopeptidase (NEP), while the aminopeptidase dipeptidylpeptidase IV (DPPIV) can also play a role. The aim of this randomized, crossover, double-blind study was to assess the cutaneous vasoreactivity (flare and wheal reaction, burning pain sensation) to intradermal injection of ascending doses of SP in six volunteers receiving a single therapeutic dose of the DPPIV inhibitor sitagliptin or a matching placebo. Cutaneous SP challenges produced the expected, dose-dependent flare and wheal response, while eliciting mild to moderate local pain sensation with little dose dependency. However, no differences were shown in the responses observed under sitagliptin compared with placebo, while the study would have been sufficiently powered to detect a clinically relevant increase in sensitivity to SP. The results of this pilot study are in line with proteolytic cleavage of SP by ACE and NEP compensating the blockade of DPPIV to prevent an augmentation of its proinflammatory action.

Vascular Integrins: Therapeutic and Imaging Targets of Tumor Angiogenesis

Cells, including endothelial cells, continuously sense their surrounding environment and rapidly adapt to changes in order to assure tissues and organs homeostasis. The extracellular matrix (ECM) provides a physical scaffold for cell positioning and represents an instructive interface allowing cells to communicate over short distances. Cell surface receptors of the integrin family emerged through evolution as essential mediators and integrators of ECM-dependent communication. In preclinical studies, pharmacological inhibition of vascular integrins suppressed angiogenesis and inhibited tumor progression. alpha(V)beta(3) and alpha(V)beta(5) were the first integrins targeted to suppress tumor angiogenesis. Subsequently, additional integrins, in particular alpha(1)beta(1), alpha(2)beta(1), alpha(5)beta(1), and alpha(6)beta(4), emerged as potential therapeutic targets. Integrin inhibitors are currently tested in clinical trials for their safety and antiangiogenic/antitumor activity. In this chapter, we review the role of integrins in angiogenesis and present recent advances in the use of integrin antagonists as potential therapeutics in cancer and discuss future perspectives.