Leukocytes, inflammation, and angiogenesis in cancer: fatal attractions.

Leukocytes are cells of defense. Their main function is to protect our body against invading microorganisms. Some leukocytes, in particular, polymorphonuclear and monocytes, accumulate at sites of infection and neutralize pathogens through innate mechanisms. The blood and lymphatic vascular system are essential partners in this defensive reaction: Activated endothelial cells promote leukocyte recruitment at inflammatory sites; new blood vessel formation, a process called angiogenesis, sustains chronic inflammation, and lymphatic vessels transport antigens and antigen-presenting cells to lymph nodes, where they stimulate naive T and B lymphocytes to elicit an antigen-specific immune response. In contrast, leukocytes and lymphocytes are far less efficient in protecting us from cancer, the "enemy from within." Worse, cancer can exploit inflammation to its advantage. The role of angiogenesis, leukocytes, and inflammation in tumor progression was discussed at the second Monte Verità Conference, Tumor Host Interaction and Angiogenesis: Basic Mechanisms and Therapeutic Perspectives, held in Ascona, Switzerland, October 1-5, 2005. (Conference chairs were K. Alitalo, M. Aguet, C. Rüegg, and I. Stamenkovic.) Eight articles reporting about topics presented at the conference are featured in this issue of the Journal of Leukocyte Biology.

Evaluation of a novel biomaterial in the suprachoroidal space of the rabbit eye.

PURPOSE: Drug delivery to treat diseases of the posterior segment of the eye, such as choroidal neovascularization and its complications, is hampered by poor intraocular penetration and rapid elimination of the drug from the eye. The purpose of this study was to investigate the feasibility and tolerance of suprachoroidal injections of poly(ortho ester) (POE), a bioerodible and biocompatible polymer, as a biomaterial potentially useful for development of sustained drug delivery systems. METHODS: After tunnelization of the sclera, different formulations based on POE were injected (100 microL) into the suprachoroidal space of pigmented rabbits and compared with 1% sodium hyaluronate. Follow-up consisted of fundus observations, echography, fluorescein angiography, and histologic analysis over 3 weeks. RESULTS: After injection, POE spread in the suprachoroidal space at the posterior pole. It was well tolerated and progressively disappeared from the site of injection without sequelae. No bleeding or retinal detachment occurred. Echographic pictures showed that the material was present in the suprachoroidal space for 3 weeks. Angiography revealed minor pigment irregularities at the site of injection, but no retinal edema or necrosis. Histology showed that POE was well tolerated in the choroid. CONCLUSIONS: POE suprachoroidal injections, an easy, controllable, and reproducible procedure, were well tolerated in the rabbit eye. POE appears to be a promising biomaterial to deliver drugs focally to the choroid and the retina.

Emerging paradigms and questions on pro-angiogenic bone marrow-derived myelomonocytic cells.

Cancer-related inflammation has emerged in recent years as a major event contributing to tumor angiogenesis, tumor progression and metastasis formation. Bone marrow-derived and inflammatory cells promote tumor angiogenesis by providing endothelial progenitor cells that differentiate into mature endothelial cells, and by secreting pro-angiogenic factors and remodeling the extracellular matrix to stimulate angiogenesis though paracrine mechanisms. Several bone marrow-derived myelonomocytic cells, including monocytes and macrophages, have been identified and characterized by several laboratories in recent years. While the central role of these cells in promoting tumor angiogenesis, tumor progression and metastasis is nowadays well established, many questions remain open and new ones are emerging. These include the relationship between their phenotype and function, the mechanisms of pro-angiogenic programming, their contribution to resistance to anti-angiogenic treatments and to metastasis and their potential clinical use as biomarkers of angiogenesis and anti-angiogenic therapies. Here, we will review phenotypical and functional aspects of bone marrow-derived myelonomocytic cells and discuss some of the current outstanding questions.

Lentiviral vectors efficiently transduce the EGFP gene into cardiomyocytes in vivo : immunohistology and Elisa quantification of the transgene

RESUME Les maladies cardio-vasculaires représentent la cause la plus importante de mortalité et de morbidité dans les pays occidentaux. La thérapie génique offre une nouvelle approche au traitement de ces maladies. L'expression de gènes protecteurs dans le myocarde par des technologies de transfert génique peut améliorer la fonction ventriculaire lors de l'insuffisance cardiaque ou stimuler la formation de nouveaux vaisseaux dans la maladie coronarienne. Etant donné qu'une majorité des maladies cardiaques sont des maladies chroniques, l'expression durable du gène thérapeutique introduit dans le coeur est souhaitable dans de nombreux cas. Malheureusement, l'utilité des vecteurs de transfert génique les plus utilisés en thérapie génique cardiovasculaire est limitée par une performance faible (ADN plasmidique) et une courte durée d'expression (adénovirus). Récemment, des vecteurs de transfert génique dérivés des lentivirus, une sous-famille des rétrovirus, ont retenu l'attention de la communauté scientifique en raison de leur capacité à exprimer des gènes à long terme. Contrairement aux vecteurs rétroviraux traditionnels, les vecteurs lentiviraux transduisent des gènes même dans des cellules qui ne se divisent pas, ce qui est le cas des cardiomyocytes adultes. Ces vecteurs présentent un profil de biosécurité comparable à celui des vecteurs rétroviraux traditionnels. Nous avons donc décidé de tester l'utilité des vecteurs lentiviraux pour le transfert génique dans des cardiomyocytes de rat adulte in vitro et in vivo. Plusieurs versions de vecteurs lentiviraux contenant différent promoteurs ont été construites. Ces vecteurs contenant le gène marqueur EGFP (enhanced green fluorescent protein) ont été testés dans des cardiomyocytes de rat in vitro, ainsi que dans des coeurs de rat in vivo. Le but de ces expériences était de déterminer la durée de l'expression du transgène après injection intramyocardique chez le rat. Pour ce faire, nous avons développé une technique ELISA pour détecter la protéine EGFP dans des extraits de tissu cardiaque. Les résultats ont montré que la protéine EGFP était encore présente à des niveaux significatifs jusqu'à dix semaines après l'injection de vecteurs lentiviraux, alors que l'expression transgénique obtenue avec un vecteur adénoviral traditionnel a été plus limitée dans le temps. Ces résultats démontrent la capacité des vecteurs lentiviraux à exprimer des gènes d'intérêt de manière performante et stable dans le cœur de rat adulte in vivo. SUMMARY Cardiovascular diseases are the first cause of morbidity and mortality in Western countries. Gene therapy offers a new approach to these diseases. Expression of therapeutic genes in the myocardium by gene transfer technologies can improve ventricular function in heart failure and stimulate neovascularization in coronary disease. Chronic heart diseases likely require sustained expression of the therapeutic gene within the heart itself. Unfortunately, the most commonly used vectors in cardiovascular gene therapy, i.e. plasmid DNA and recombinant adenovirus vectors, are limited by poor DNA uptake and transient transgene expression, respectively. Recently, lentivirus-derived vectors have attracted much interest because of their ability to achieve long-term transgene expression. In contrast to traditional retroviral vectors, lentiviral vectors are also able to transduce non- dividing cells, while presenting a comparable biosafety profile. Adult cardiomyocytes are terminally differentiated cells that do not divide under normal conditions. For these reasons, we have decided to evaluate the efficiency of lentiviral vectors for gene-transduction of adult cardiomyocytes both in vitro and in vivo. We constructed various types of lentiviral vectors containing various promoters. Vectors encoding EGFP as a reporter gene were tested in rat cardiomyocytes in vitro and in rat hearts in vivo. The aim of the experiments involved in this thesis work was to determine the duration of the expression of the transgene after rat intramyocardial injection using a quantitative assay. Therefore, an ELISA technique was set up to measure the EGFP protein in rat heart tissue extracts. Our results showed that the EGFP protein was still present at significant levels at ten weeks after lentiviral vector injection, whereas the duration of expression with adenoviral vectors was shorter. These results demonstrate that lentiviral vectors efficiently deliver genes and achieve sustained transgene expression in adult rat cardiomyocytes in vivo.

Abrogation of HMX1 function causes rare oculoauricular syndrome associated with congenital cataract, anterior segment dysgenesis, and retinal dystrophy.

PURPOSE: To define the phenotypic manifestation, confirm the genetic basis, and delineate the pathogenic mechanisms underlying an oculoauricular syndrome (OAS). METHODS: Two individuals from a consanguineous family underwent comprehensive clinical phenotyping and electrodiagnostic testing (EDT). Genome-wide microarray analysis and Sanger sequencing of the candidate gene were used to identify the likely causal variant. Protein modelling, Western blotting, and dual luciferase assays were used to assess the pathogenic effect of the variant in vitro. RESULTS: Complex developmental ocular abnormalities of congenital cataract, anterior segment dysgenesis, iris coloboma, early-onset retinal dystrophy, and abnormal external ear cartilage presented in the affected family members. Genetic analyses identified a homozygous c.650A>C; p.(Gln217Pro) missense mutation within the highly conserved homeodomain of the H6 family homeobox 1 (HMX1) gene. Protein modelling predicts that the variant may have a detrimental effect on protein folding and/or stability. In vitro analyses were able to demonstrate that the mutation has no effect on protein expression but adversely alters function. CONCLUSIONS: Oculoauricular syndrome is an autosomal recessive condition that has a profound effect on the development of the external ear, anterior segment, and retina, leading to significant visual loss at an early age. This study has delineated the phenotype and confirmed HMX1 as the gene causative of OAS, enabling the description of only the second family with the condition. HMX1 is a key player in ocular development, possibly in both the pathway responsible for lens and retina development, and via the gene network integral to optic fissure closure.

Frequent nitric oxide synthase-2 expression in human colon adenomas: implication for tumor angiogenesis and colon cancer progression.

An increased expression of nitric oxide synthase (NOS) has been observed in human colon carcinoma cell lines as well as in human gynecological, breast, and central nervous system tumors. This observation suggests a pathobiological role of tumor-associated NO production. Hence, we investigated NOS expression in human colon cancer in respect to tumor staging, NOS-expressing cell type(s), nitrotyrosine formation, inflammation, and vascular endothelial growth factor expression. Ca2+-dependent NOS activity was found in normal colon and in tumors but was significantly decreased in adenomas (P < 0.001) and carcinomas (Dukes' stages A-D: P < 0.002). Ca2+-independent NOS activity, indicating inducible NOS (NOS2), is markedly expressed in approximately 60% of human colon adenomas (P < 0.001 versus normal tissues) and in 20-25% of colon carcinomas (P < 0.01 versus normal tissues). Only low levels were found in the surrounding normal tissue. NOS2 activity decreased with increasing tumor stage (Dukes' A-D) and was lowest in colon metastases to liver and lung. NOS2 was detected in tissue mononuclear cells (TMCs), endothelium, and tumor epithelium. There was a statistically significant correlation between NOS2 enzymatic activity and the level of NOS2 protein detected by immunohistochemistry (P < 0.01). Western blot analysis of tumor extracts with Ca2+-independent NOS activity showed up to three distinct NOS2 protein bands at Mr 125,000-Mr 138,000. The same protein bands were heavily tyrosine-phosphorylated in some tumor tissues. TMCs, but not the tumor epithelium, were immunopositive using a polyclonal anti-nitrotyrosine antibody. However, only a subset of the NOS2-expressing TMCs stained positively for 3-nitrotyrosine, which is a marker for peroxynitrite formation. Furthermore, vascular endothelial growth factor expression was detected in adenomas expressing NOS2. These data are consistent with the hypothesis that excessive NO production by NOS2 may contribute to the pathogenesis of colon cancer progression at the transition of colon adenoma to carcinoma in situ.

Corticosteroids and the retina: a role for the mineralocorticoid receptor.

PURPOSE OF REVIEW: Long-lasting devices releasing steroids have been approved recently for macular edema of various origins. Identification of the retina as a novel mineralo-sensitive tissue also raises new therapeutic options. RECENT FINDINGS: Recently, the over activation of the mineralocorticoid receptor (MR) pathway has been shown to cause fluid accumulation in the retina, choroidal vasodilation, and to promote retinal neovascularization in hypoxic conditions. These findings indicate that MR antagonists could have beneficial effects in the treatment of retinal diseases. Central serous chorioretinopathy is a retinal disease associated with choroidal vasodilation and subretinal fluid that affects mostly men with type A personality and occurrence has been associated with steroid intake. In several independent studies, MR antagonists have shown beneficial effects, significantly reducing subretinal fluid in eyes of chronic central serous chorioretinopathy patients. SUMMARY: The role of MR in retinal disorder is emerging and the potential association with psychological traits is considered. The place of MR antagonists for retinal diseases treatment is discussed.

Posterior Sub-Tenon Triamcinolone Injection for Chronic Macular Oedema Associated With Non-Ischemic Branch or Central Retinal Vein Occlusion

Aims: To evaluate the effectiveness and safety of Posterior Sub-Tenon (PST) Triamcinolone Acetonide (TA) injection for persistent macular oedema associated with non-ischemic Central Retinal Vein Occlusion (CRVO) or Branch Retinal Vein Occlusion (BRVO) in non-vitrectomized eye. Methods: Fourteen consecutive eyes of 14 patients characterized by macular oedema lasting more than 3 months and with a visual acuity of less than 20/40 were enrolled. Six eyes presented with BRVO, 8 eyes with CRVO. PST injection of 40 mg TA was performed in topical anaesthesia. All patients were phakic, and followed for at least 6 months. Snellen visual acuity converted to LogMAR units and anatomic responses were evaluated before, and at 1, 3, 6, and 12 (if required) months after injections and re-injection considered. Results: In the BRVO group, mean foveal thickness was 548.2±49.50 μm preoperatively, and 452.8±56.2 μm and 280.8±62.5 μm at 1 and 12 month follow-up, respectively. Statistical analysis showed significant differences between preoperative and postoperative measurements (P<.05, paired t test) 3 months after injections. Improvement of visual acuity by at least 0.2 LogMAR was seen in 3(50%) of the 6 eyes. No re-injection was needed. In the CRVO group, mean foveal thickness was 543.7±34.4 μm preoperatively, and 283.0±29.0 μm and 234.8±23.6 μm at 1 and 12 month follow-up, respectively. Statistical analysis showed significant differences between preoperative and postoperative measurements (P<.05, paired t test). Improvement of visual acuity by at least 0.2 LogMAR was seen in 7 eyes (88%). Mean number of re-injection was of 2.1±0.3. Intraocular pressure elevation of 22 mm Hg or higher was found in 2/14 eyes (14%). Cataract progression was noted in 5/14 eyes (36%). Conclusions: PST injection of TA appears to be as safe and effective treatment for chronic macular oedema associated due to both non-ischemic BRVO or CRVO, with a better efficacy in BRVO.

Ostéome choroïdien unilatéral chez un enfant de 2 ans

Un garçon, âgé de 2 ans, est suivi depuis ses 1 an pour une hétérochromie sectorielle de l'iris au niveau de l'oeil gauche. Au dernier contrôle ophtalmologique, le médecin traitant a découvert une lésion blanchâtre du fond d'oeil, au même oeil. Il a suspecté un rétinoblastome et nous a adressé l'enfant pour prise en charge diagnostique et thérapeutique. ▶ Examen sous narcose : L'examen du fond d'oeil gauche révèle une lésion blanc-jaunâtre, ovalaire, à bords festonnés, légèrement surélevée, localisée au pôle postérieur et atteignant l'arcade temporale supérieure. L'examen de l'oeil droit est sans particularités.

Experimental Cournot oligopoly and inequity aversion

This paper explores the role of inequity aversion as an explanation for observed behavior in experimental Cournot oligopolies. We show that inequity aversion can change the nature of the strategic interaction: quantities are strategic substitutes for sufficiently asymmetric output levels but strategic complements otherwise. We find that inequity aversion can explain why: (i) some experiments result in higher than Cournot-Nash production levels while others result in lower, (ii) collusion often occurs with only two players whereas with three or more players market outcomes are very close to Cournot-Nash, and (iii) players often achieve equal profits in asymmetric Cournot oligopoly.

Tacit Collusion under Fairness and Reciprocity

This paper departs from the standard profit-maximizing model of firm behavior by assuming that firms are motivated in part by personal animosity-or respect-towards their competitors. A reciprocal firm responds to unkind behavior of rivals with unkind actions (negative reciprocity), while at the same time, it responds to kind behavior of rivals with kind actions (positive reciprocity). We find that collusion is easier to sustain when firms have a concern for reciprocity towards competing firms provided that they consider collusive prices to be kind and punishment prices to be unkind. Thus, reciprocity concerns among firms can have adverse welfare consequences for consumers.