Comparative assessment of intimal hyperplasia development after 14 days in two different experimental settings: tissue culture versus ex vivo continuous perfusion of human saphenous vein.

BACKGROUND: Intimal hyperplasia (IH) is a vascular remodeling process which often leads to failure of arterial bypass or hemodialysis access. Experimental and clinical work have provided insight in IH development; however, further studies under precise controlled conditions are required to improve therapeutic strategies to inhibit IH development. Ex vivo perfusion of human vessel segments under standardized hemodynamic conditions may provide an adequate experimental approach for this purpose. Therefore, chronically perfused venous segments were studied and compared to traditional static culture procedures with regard to functional and histomorphologic characteristics as well as gene expression. MATERIALS AND METHODS: Static vein culture allowing high tissue viability was performed as previously described. Ex vivo vein support system (EVVSS) was performed using a vein support system consisting of an incubator with a perfusion chamber and a pump. EVVSS allows vessel perfusion under continuous flow while maintaining controlled hemodynamic conditions. Each human saphenous vein was divided in two parts, one cultured in a Pyrex dish and the other part perfused in EVVSS for 14days. Testing of vasomotion, histomorphometry, expression of CD 31, Factor VIII, MIB 1, alpha-actin, and PAI-l were determined before and after 14days of either experimental conditions. RESULTS: Human venous segments cultured under traditional or perfused conditions exhibited similar IH after 14 days as shown by histomorphometry. Smooth-muscle cell (SMC) was preserved after chronic perfusion. Although integrity of both endothelial and smooth-muscle cells appears to be maintained in both culture conditions as confirmed by CD31, factor VIII, and alpha-actin expression, a few smooth-muscle cells in the media stained positive for factor VIII. Cell-proliferation marker MIB-1 was also detected in the two settings and PAI-1 mRNA expression and activity increased significantly after 14 days of culture and perfusion. CONCLUSION: This study demonstrates the feasibility to chronically perfuse human vessels under sterile conditions with preservation of cellular integrity and vascular contractility. To gain insights into the mechanisms leading to IH, it will now be possible to study vascular remodeling not only under static conditions but also in hemodynamic environment mimicking as closely as possible the flow conditions encountered in reconstructive vascular surgery.

A gene expression signature that distinguishes desmoid tumours from nodular fasciitis.

Nodular fasciitis (NF) is a rapidly growing cellular mass composed of fibroblasts/myofibroblasts, usually localized in subcutaneous tissues, that typically undergoes fibrosis and almost never recurs. Desmoid tumours (DTs) are rare forms of fibroblastic/myofibroblastic growth that arise in deep soft tissues, display a propensity for local infiltration and recurrence, but fail to metastasize. Given that both entities are primarily fibroblastic/myofibroblastic lesions with overlapping histological features, their gene expression profiles were compared to identify differentially expressed genes that may provide not only potential diagnostic markers, but also clues as to the pathogenesis of each disorder. Differentially expressed transcripts (89 clones displaying increased expression in DTs and 246 clones displaying increased expression in NF) included genes encoding several receptor and non-receptor tyrosine kinases (EPHB3, PTPRF, GNAZ, SYK, LYN, EPHA4, BIRC3), transcription factors (TWIST1, PITX2, EYA2, OAS1, MITF, TCF20), and members of the Wnt signalling pathway (AXIN2, WISP1, SFRP). Remarkably, almost one-quarter of the differentially expressed genes encode proteins associated with inflammation and tissue remodelling, including members of the interferon (IFN), tumour necrosis factor (TNF), and transforming growth factor beta (TGF-beta) signalling pathways as well as metalloproteinases (MMP1, 9, 13, 23), urokinase plasminogen activator (PLAU), and cathepsins. The observations provide the first comparative molecular characterization of desmoid tumours and nodular fasciitis and suggest that selected tyrosine kinases, transcription factors, and members of the Wnt, TGF-beta, IFN, and TNF signalling pathways may be implicated in influencing and distinguishing their fate.

Hyperaldostéronisme primaire sur adénome ou hyperplasie de la surrénale: opérer ou non [Primary hyperaldosteronism with adrenal adenoma or hyperplasia: surgical case or not?].

Primary hyperaldosteronism is one of the most frequent causes of secondary hypertension. Cardiovascular morbimortality is higher than in essential hypertonic and justifies diagnostic and specific treatment of this pathology. Therapeutic choice depends of health and desire of the patient. It is either medical with mineralocorticoid receptor antagonists, or surgical through adrenalectomy. In this case, a pre-surgery exam including a radiologic examination and a venous adrenal catheterism has to be done. Surgery allows a normalisation of kaliema and a blood pressure decrease in 50 to 88% of the patients. Beyond them, 30% are able to stop entirely their medication. Both therapeutic choices decrease cardiovascular risks equally if blood pressure is controlled.

Ex vivo Pulsatile Perfusion of Human Saphenous Veins Induces Intimal Hyperplasia and Increased Levels of the Plasminogen Activator Inhibitor 1.

Vessel wall trauma induces vascular remodeling processes including the development of intimal hyperplasia (IH). To assess the development of IH in human veins, we have used an ex vivo vein support system (EVVSS) allowing the perfusion of freshly isolated segments of saphenous veins in the presence of a pulsatile flow which reproduced arterial conditions regarding shear stress, flow rate and pressure during a period of 7 and 14 days. Compared to the corresponding freshly harvested human veins, histomorphometric analysis showed a significant increase in the intimal thickness which was already maximal after 7 days of perfusion. Expression of the endothelial marker CD31 demonstrated the presence of endothelium up to 14 days of perfusion. In our EVVSS model, the activity as well as the mRNA and protein expression levels of plasminogen activator inhibitor 1, the inhibitor of urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA), were increased after 7 days of perfusion, whereas the expression levels of tPA and uPA were not altered. No major change was observed between 7 and 14 days of perfusion. These data show that our newly developed EVVSS is a valuable setting to study ex vivo remodeling of human veins submitted to a pulsatile flow.

Foxm1 expression in prostate epithelial cells is essential for prostate carcinogenesis.

The treatment of advanced prostate cancer (PCa) remains a challenge. Identification of new molecular mechanisms that regulate PCa initiation and progression would provide targets for the development of new cancer treatments. The Foxm1 transcription factor is highly up-regulated in tumor cells, inflammatory cells, and cells of tumor microenvironment. However, its functions in different cell populations of PCa lesions are unknown. To determine the role of Foxm1 in tumor cells during PCa development, we generated two novel transgenic mouse models, one exhibiting Foxm1 gain-of-function and one exhibiting Foxm1 loss-of-function under control of the prostate epithelial-specific Probasin promoter. In the transgenic adenocarcinoma mouse prostate (TRAMP) model of PCa that uses SV40 large T antigen to induce PCa, loss of Foxm1 decreased tumor growth and metastasis. Decreased prostate tumorigenesis was associated with a decrease in tumor cell proliferation and the down-regulation of genes critical for cell proliferation and tumor metastasis, including Cdc25b, Cyclin B1, Plk-1, Lox, and Versican. In addition, tumor-associated angiogenesis was decreased, coinciding with reduced Vegf-A expression. The mRNA and protein levels of 11β-Hsd2, an enzyme playing an important role in tumor cell proliferation, were down-regulated in Foxm1-deficient PCa tumors in vivo and in Foxm1-depleted TRAMP C2 cells in vitro. Foxm1 bound to, and increased transcriptional activity of, the mouse 11β-Hsd2 promoter through the -892/-879 region, indicating that 11β-Hsd2 was a direct transcriptional target of Foxm1. Without TRAMP, overexpression of Foxm1 either alone or in combination with inhibition of a p19(ARF) tumor suppressor caused a robust epithelial hyperplasia, but was insufficient to induce progression from hyperplasia to PCa. Foxm1 expression in prostate epithelial cells is critical for prostate carcinogenesis, suggesting that inhibition of Foxm1 is a promising therapeutic approach for prostate cancer chemotherapy.

Comparative assessement of intimal hyperplasia development after 14 days in two different experimental settings : tissue culture versus ex vivo continuous perfusion of human saphenous vein

Résumé de l'article : L'hyperplasie intimale est un processus de remodelage vasculaire ubiquitaire après une lésion, pouvant menacer la perméabilité de tout type de reconstruction vasculaire. Les mécanismes physiopathologiques impliqués dans le développement de l'hyperplasie intimale ne sont que partiellement élucidés. Il est par conséquent nécessaire d'effectuer des recherches complémentaires afin d'en améliorer la compréhension et ainsi permettre l'élaboration de nouvelles stratégies thérapeutiques médicamenteuses. La culture de veines en milieu statique permet le développement de l'hyperplasie intimale. Ce modèle maintient la viabilité tissulaire, comme décrit précédemment dans d'autres études, mais empêche l'analyse des paramètres hémodynamiques. La mise au point d'un modèle de perfusion in vitro permettant la perfusion de segments vasculaires représente une approche expérimentale intégrant les différents facteurs hémodynamiques. Le système de perfusion (Ex Vivo Vein Support System) que nous avons élaboré conserve l'intégrité pariétale ainsi que les propriétés vasomotrices des veines pour une durée de 14 jours. Cette étude démontre que les deux modèles permettent le développement de l'hyperplasie intimale. Toutefois, les propriétés vasomotrices ainsi que l'influence des paramètres hémodynamiques ne peuvent être analysées que par l'utilisation du système de perfusion. Ce dernier a permis de perfuser des vaisseaux humains sans contamination bactérienne tout en maintenant l'intégrité cellulaire. Ce modèle de perfusion se rapproche plus des conditions hémodynamiques rencontrées in vivo que le modèle statique. Abstract : Background. Intimal hyperplasia (IH) is a vascular remodeling process which often leads to failure of arterial bypass or hemodialysis access. Experimental and clinical work have provided insight in IH development; however, further studies under precise con-trolled conditions are required to improve therapeutic strategies to inhibit IH development. Ex vivo perfusion of human vessel segments under standardized hemodynamic conditions may provide an adequate experimental approach for this purpose. Therefore, chronically perfused venous segments were studied and compared to traditional static culture procedures with regard to functional and histomorphologic characteristics as well as gene expression. Materials and methods. Static vein culture allowing high tissue viability was performed as previously described. Ex vivo vein support system (EVVSS) was performed using a vein support system consisting of an incubator with a perfusion chamber and a pump. EVVSS allows vessel perfusion under continuous flow while maintaining controlled hemodynamic conditions. Each human saphenous vein was divided in two parts, one cultured in a Pyrex dish and the other part perfused in EVVSS for 14 days. Testing of vasomotion, histomorphometry, expression of CD 31, Factor VIII, MIB 1, α-actin, and PAI-1 were determined before and after 14 days of either experimental conditions. Results, Human venous segments cultured under traditional or perfused conditions exhibited similar IH after 14 days as shown by histomorphometry. Smooth-muscle cell ( SMC) was preserved after chronic perfusion. Although integrity of both endothelial and smooth-muscle cells appears to be maintained in both culture conditions as confirmed by CD31, factor VIII and α-actin expression, a few smooth-muscle cells in the media stained positive for factor VIII. Cell-proliferation marker MIB-1 was also detected in the two settings and PAI-1 mRNA expression and activity increased significantly after 14 days of culture and perfusion. Conclusion. This study demonstrates the feasibility to chronically perfuse human vessels under sterile conditions with preservation of cellular integrity and vascular contractility. To gain insights into the mechanisms leading to IH, it will now be possible to study vascular remodeling not only under static conditions but also in hemodynamic environment mimicking as closely as possible the flow conditions encountered in reconstructive vascular surgery.

Urologie [Urology]

In prostatic cancer, PSA velocity is a reliable sign of cancer agressivity. In the metastatic prostatic cancer, there is no difference on survival between an early and late hormonal treatment. In the invasive bladder cancer néo-adjuvant chemotherapy offers a light advantage. In the kidney cancer, anti-angiogenic agents increase the survival. In the non neurogenic overactive bladder, no studies have led to relevant results in using antimuscarinic agent in the first line. The 5 phophodiesterase inhibitors used in the treatment of erectile dysfunction are also effective in the treatment of trouble induced by benign prostatic hyperplasia.

The use of external mesh reinforcement to reduce intimal hyperplasia and preserve the structure of human saphenous veins.

The saphenous vein is the conduit of choice in bypass graft procedures. Haemodynamic factors play a major role in the development of intimal hyperplasia (IH), and subsequent bypass failure. To evaluate the potential protective effect of external reinforcement on such a failure, we developed an ex vivo model for the perfusion of segments of human saphenous veins under arterial shear stress. In veins submitted to pulsatile high pressure (mean pressure at 100 mmHg) for 3 or 7 days, the use of an external macroporous polyester mesh 1) prevented the dilatation of the vessel, 2) decreased the development of IH, 3) reduced the apoptosis of smooth muscle cells, and the subsequent fibrosis of the media layer, 4) prevented the remodelling of extracellular matrix through the up-regulation of matrix metalloproteinases (MMP-2, MMP-9) and plasminogen activator type I. The data show that, in an experimental ex vivo setting, an external scaffold decreases IH and maintains the integrity of veins exposed to arterial pressure, via increase in shear stress and decrease wall tension, that likely contribute to trigger selective molecular and cellular changes.

The use of telomerase activity for the detection of prostatic cancer cells after prostatic massage.

PURPOSE: Prostate cancer is the most commonly diagnosed cancer in the United States. The diagnosis or followup of prostate cancer in men older than 50 years is based on digital rectal examination, measurement of the free-to-total prostatic specific antigen ratio and transrectal ultrasound assisted needle biopsy of the prostate. We developed and evaluated a noninvasive method for diagnosing prostate cancer based on the measurement of telomerase activity after prostatic massage in fresh voided urine or after urethral washing. MATERIALS AND METHODS: We obtained 36 specimens of cells after prostatic massage in the fresh voided urine of 16 patients who subsequently underwent radical prostatectomy and after urethral washing in 20 who underwent prostate needle biopsies. Ethylenediaminetetraacetic acid was immediately added to the collected urine or washing to a final concentration of 20 mM. After protein extraction by CHAPS buffer each specimen was tested for telomerase activity in a 2-step modified telomeric repeat amplification protocol assay. The 2 prostate cancer cell lines PC-3 and LNCaP with high telomerase activity were used as a positive control. RESULTS: Telomerase activity was detected in 14 of 24 samples with known prostate cancer (sensitivity 58%). In contrast, no telomerase activity was found in the 12 cases without histological evidence of prostate tumor (specificity 100%). Eight of 9 poorly differentiated cancers expressed telomerase activity (89%), while only 6 of 15 well and moderately differentiated cancers showed telomerase activity (40%). CONCLUSIONS: Our data illustrate that telomerase activity may be detected in voided urine or washing after prostatic massage in patients with prostate cancer. Sensitivity was higher for poorly differentiated tumors. This approach is not currently available for detecting prostate cancer in clinical practice. However, these results are promising and further studies are ongoing.

Soybean (Glycine max. L.) and bacteroid glyoxylate cycle activities during nodular senescence.

Soybean (Glycine max. L.) nodular senescence results in the dismantling of the peribacteroid membrane (PBM) and in an increase of soybean isocitrate lyase (ICL; EC 4.1.3.1) and malate synthase (MS; EC 4.1.3.2) mRNA and protein levels. This suggests that in senescing soybean nodular cells, the specific glyoxylate cycle enzyme activities might be induced to reallocate carbon obtained from the PBM degradation. In order to evaluate as well the carbon metabolism of the nitrogen-fixing Bradyrhizobium japonicum endosymbiotic bacteroids during nodular senescence, their glyoxylate cycle activities were also investigated. To this end, partial DNA sequences were isolated from their icl and ms genes, but the corresponding mRNAs were not detected in the microorganisms. It was also observed that the bacteroid ICL and MS activities were negligible during nodular senescence. This suggests that glyoxylate cycle activities are not reinitiated in the bacteroids under these physiological conditions. In case the microorganisms nevertheless feed on the PBM degradation products, this might occur via the citric acid cycle exclusively.

Soybean (Glycine max. L.) and bacteroid glyoxylate cycle activities during nodular senescence

Soybean (Glycine max. L.) nodular senescence results in the dismantling of the peribacteroid membrane (PBM) and in an increase of soybean isocitrate lyase (ICL; EC 4.1.3.1) and malate synthase (MS; EC 4.1.3.2) mRNA and protein levels. This suggests that in senescing soybean nodular cells, the specific glyoxylate cycle enzyme activities might be induced to reallocate carbon obtained from the PBM degradation. In order to evaluate as well the carbon metabolism of the nitrogen-fixing Bradyrhizobium japonicum endosymbiotic bacteroids during nodular senescence, their glyoxylate cycle activities were also investigated. To this end, partial DNA sequences were isolated from their icl and ms genes, but the corresponding mRNAs were not detected in the microorganisms. It was also observed that the bacteroid ICL and MS activities were negligible during nodular senescence. This suggests that glyoxylate cycle activities are not reinitiated in the bacteroids under these physiological conditions. In case the microorganisms nevertheless feed on the PBM degradation products, this might occur via the citric acid cycle exclusively.

Fábricas cristalinas de la anhidrita nodular y laminada

Del estudio de un numero significativo de preparaciones microscópicas de rocas de anhidrita pertenecientes a formaciones de litofacies. edades y ambientes sedimentarios diferentes (quedan excluidas del presente estudio las anhidritas de reemplazamiento diagenetico de formaciones carbonatadas) se destaca la existencia de dos hábitos cristalinos principales que definen las fabricas de este mineral: a) equidimensional (granular). y b) prismático-elongado (prismatico). Ambos corresponden respectivamente, en primera aproximacien, a los terminos anglosajones depile ofbricks y lar11 testure. El predominio en las fabricas de un solo habito cristalino de tamaño de grano relativamente uniforme permite calificarlas de homogeneas

Connexin43 Inhibition Prevents Human Vein Grafts Intimal Hyperplasia.

Venous bypass grafts often fail following arterial implantation due to excessive smooth muscle cells (VSMC) proliferation and consequent intimal hyperplasia (IH). Intercellular communication mediated by Connexins (Cx) regulates differentiation, growth and proliferation in various cell types. Microarray analysis of vein grafts in a model of bilateral rabbit jugular vein graft revealed Cx43 as an early upregulated gene. Additional experiments conducted using an ex-vivo human saphenous veins perfusion system (EVPS) confirmed that Cx43 was rapidly increased in human veins subjected ex-vivo to arterial hemodynamics. Cx43 knock-down by RNA interference, or adenoviral-mediated overexpression, respectively inhibited or stimulated the proliferation of primary human VSMC in vitro. Furthermore, Cx blockade with carbenoxolone or the specific Cx43 inhibitory peptide 43gap26 prevented the burst in myointimal proliferation and IH formation in human saphenous veins. Our data demonstrated that Cx43 controls proliferation and the formation of IH after arterial engraftment.

Hiperplasia nodular focal do fígado: apresentação de um caso e revisão da literatura

Neste trabalho apresentamos um caso de hiperplasia nodular focal que foi diagnosticado aos seis anos de idade e que está sendo acompanhado até o momento presente. Para o diagnóstico foram imprescindíveis as técnicas de imagem, tendo importância de realce a cintilografia hepatoesplênica e a tomografia computadorizada. Apresentamos, também, revisão da literatura sobre o assunto.