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Endothelial Layer (endothelial + layer)
Selected AbstractsA detailed microscopic study of the changes in the aorta of experimental model of postmenopausal rats fed with repeatedly heated palm oilINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 3 2009Siti Khadijah Adam Summary Hypercholesterolaemia, increase in lipid peroxidation and hyperhomocysteinaemia may contribute to the pathogenesis of atherosclerosis. This study was performed to examine the effects of repeatedly heated palm oil mixed with 2% cholesterol diet on atherosclerosis in oestrogen-deficient postmenopausal rats. Ovariectomy causes disruption of tunica intima layer of the rat aorta simulating a postmenopausal condition in females. Twenty-four ovariectomized female Sprague,Dawley rats were divided into four groups. The control group received 2% cholesterol diet without palm oil. A diet with 2% cholesterol content fortified with fresh, once-heated and five-times-heated palm oil was given to the other treatment groups. The rats were sacrificed at the end of 4 months of study and the aortic arch tissue was processed for histomorphometry and electron microscopy. On observation, there was disruption of the intimal layer of the ovariectomized rat aorta. There was no obvious ultrastructural change in the aorta of the rats fed with fresh palm oil. The ultrastructural changes were minimal with once-heated palm oil, in which there was a focal disruption of the endothelial layer. The focal disruption was more pronounced with five-times-heated palm oil. The results of this study show that the ingestion of fresh palm oil may have a protective effect on the aorta but such a protective action may be lost when the palm oil is repeatedly heated. The study may be clinically important for all postmenopausal women who are susceptible to atherosclerosis. [source] The influence of endothelial cells on the ECM composition of 3D engineered cardiovascular constructs,JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 1 2009Rolf A. A. Pullens Abstract Tissue engineering of small diameter (<5 mm) blood vessels is a promising approach to develop viable alternatives for autologous vascular grafts. Development of a functional, adherent, shear resisting endothelial cell (EC) layer is one of the major issues limiting the successful application of these tissue engineered grafts. The goal of the present study was to create a confluent EC layer on a rectangular 3D cardiovascular construct using human venous cells and to determine the influence of this layer on the extracellular matrix composition and mechanical properties of the constructs. Rectangular cardiovascular constructs were created by seeding myofibroblasts (MFs) on poly(glycolic acid) poly-4-hydroxybutyrate scaffolds using fibrin gel. After 3 or 4 weeks, ECs were seeded and co-cultured using EGM-2 medium for 2 or 1 week, respectively. A confluent EC layer could be created and maintained for up to 2 weeks. The EGM-2 medium lowered the collagen production by MFs, resulting in weaker constructs, especially in the 2 week cultured constructs. Co-culturing with ECs slightly reduced the collagen content, but had no additional affect on the mechanical performance. A confluent endothelial layer was created on 3D human cardiovascular constructs. The layer was co-cultured for 1 and 2 weeks. Although, the collagen production of the MFs was slightly lowered, co-culturing ECs for 1 week results in constructs with good mechanical properties and a confluent EC layer. Copyright © 2008 John Wiley & Sons, Ltd. [source] Histochemical analysis of lymphatic endothelial cells in lymphostasisMICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2001Rui-Cheng Ji Abstract The ultrastructure of endothelial cells of intestinal lymphatics and the thoracic duct (TD) and the relation to lymphostasis were examined in rats and monkeys. Localization of 5,-nucleotidase (5,-Nase) and endothelial nitric oxide synthase (eNOS) was studied. In normal lymphatic endothelial cells, 5,-Nase reaction product was evenly deposited on the cell surface in vivo and on cultured TD endothelial cells (TDECs), whereas eNOS was evenly distributed throughout the nucleus and cytoplasm. TDECs had a long filamentous process extending towards the subendothelial extracellular matrix but became flat and regular within 30,40 minutes after gastric perfusion with olive oil. According to their electron-density, two types of cells were found in the TD endothelial layer. The cells with low electron-density exhibited stronger 5,-Nase activity. Valves were bicuspid formations and the valvular endothelial surface of the convex side showed weaker 5,-Nase activity than the concave side. During TD blockage-induced lymphostasis in rats, the 5,-Nase product was almost not discernible in the TDECs within 2 weeks. Larger vesicles were found in the endothelial cytoplasm of the ligated TD. Their number decreased after 6,12 weeks. The small intestinal lymphatics in the mucosa and submucosa were dilated, with numerous open intercellular junctions. The endothelial lining appeared to have reduced activities for 5,-Nase and eNOS in 9 of 11 experimental animals. The results indicated that the inability of the open intercellular junctions, normally working as one-way endothelial flap valves, may be a key morphological feature after TD blockage. Reduced eNOS and 5,-Nase may functionally influence contractile activity and transport capability of the lymphatic vessels in the lymphostasis. Microsc. Res. Tech. 55:70,80, 2001. © 2001 Wiley-Liss, Inc. [source] Expression and Activity of Heme Oxygenase-1 in Artificially Induced Low-Flow Priapism in Rat Penile TissuesTHE JOURNAL OF SEXUAL MEDICINE, Issue 8 2008Yong Chun Jin ABSTRACT Introduction., The inducible isoform of heme oxygenase (HO)-1 regulates the vascular smooth muscle tone and responds to hypoxia. Aim., To investigate the role of HO-1 in a low-flow priapism. Materials and Methods., Sixty male Sprague-Dawley rats were divided into five groups of six rats each. Each group of rats was sacrificed at 0 hour (group 1, control), 4 hours (group 2), 8 hours (group 3), 12 hours (group 4), and 24 hours (group 5) after inducing an artificial veno-occlusive priapism. The changes of the expression and activity of HO-1, and the expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS), and levels of cyclic guanosine monophosphate in the penis were examined in a low-flow priapism. In addition, the HO-1 expression level in the aortas from each group was simultaneously measured to determine whether the changes in HO-1 were systemic. Main Outcome Measures., The expression and activity of HO-1 was examined in artificially induced veno-occlusive priapism in rat penile tissues. Results., The expression of the HO-1 protein and the HO-1 enzyme activities in the penile tissues were gradually increased as time increased from 0 to 24 hours (P < 0.01). HO-1 immunoreactivities were localized in the endothelial layer of the cavernosal sinusoids. The expression of iNOS were also increased at 12 and 24 hours. The cyclic guanosine monophosphate level was also significantly increased at 24 hours (P < 0.05). However, the expression of the eNOS protein showed no statistically significant change with time, and the expression of the HO-1 protein in the aorta also showed no significant change with time. Conclusions., A higher induction of HO-1 with time was observed in artificially induced veno-occlusive priapism, which might play a protective role against hypoxic injury. However, this may also play an important role in the vicious circle observed in a low-flow priapism. Jin YC, Gam SC, Jung JH, Hyun JS, Chang KC, and Hyun JS. Expression and activity of heme oxygenase-1 in artificially induced low-flow priapism in rat penile tissues. J Sex Med 2008;5:1876,1882. [source] A Bsister MADS-box gene involved in ovule and seed development in petunia and ArabidopsisTHE PLANT JOURNAL, Issue 6 2006Stefan De Folter Summary MADS-domain transcription factors are essential for proper flower and seed development in angiosperms and their role in determination of floral organ identity can be described by the ,ABC model' of flower development. Recently, close relatives of the B-type genes were identified by phylogenetic studies, which are referred to as Bsister (Bs) genes. Here, we report the isolation and characterization of a MADS-box Bs member from petunia, designated FBP24. An fbp24 knock-down line appeared to closely resemble the Arabidopsis Bs mutant abs and a detailed and comparative analysis led to the conclusion that both FBP24 and ABS are necessary to determine the identity of the endothelial layer within the ovule. Protein interaction studies revealed the formation of higher-order complexes between Bs,C,E and Bs,D,E type MADS-box proteins, suggesting involvement of these specific complexes in determination of endothelium identity. However, although there are many similarities between the two genes and their products and functions, interestingly FBP24 cannot replace ABS in Arabidopsis. The results presented here demonstrate the importance of the comparative analysis of key regulatory genes in various model systems to fully understand all aspects of plant development. [source] Preservation of Muscular and Elastic Artery Distensibility After an Intercontinental Cryoconserved Exchange: Theoretical Advances in Arterial Homograft Generation and UtilizationARTIFICIAL ORGANS, Issue 8 2009Daniel Bia Abstract While the situation of tissue donation and transplantation differs between Latin American and European countries, a common problem is tissue deficiency. Hence, at present, there is a pressing need to generate alternatives so as to increase the possibilities of obtaining the requested materials. Consequently, it would be of significant interest to establish an intercontinental network for tissue exchange, to improve international cooperation, and to help patients that need tissue transplantation, and to evaluate the feasibility of using an intercontinental network for the exchange of cryopreserved arteries (cryografts), preserving the arterial distensibility and ensuring a reduced native artery,cryograft biomechanical mismatch. Distensibility was studied in ovine arteries divided into three groups: intact (in vivo tests, conscious animals), fresh control (in vitro tests immediately after the artery excision, Uruguay), and cryografts (in vitro tests of cryopreserved-transported-defrosted arteries, Spain). Histological studies were performed so as to analyze changes in the endothelial layer and elastic components. The comparison between fresh control and cryografts showed that neither the cryopreservation nor the exchange network impaired the distensibility, despite the expected histological changes found in the cryografts. The comparison between intact and cryografts showed that the cryografts would be capable of ensuring a reduced biomechanical mismatch. The cryopreservation and the intercontinental network designed for artery exchange preserved the arterial distensibility. It could be possible to transfer cryografts between Latin America and Europe to be used in cardiovascular surgeries and/or for tissue banking reprocessing, with basic biomechanical properties similar to those of the fresh and/or native arteries. [source] In vitro viability of human cavernosal endothelial and fibroblastic cells after exposure to papaverine/phentolamine and prostaglandin E1BJU INTERNATIONAL, Issue 9 2005Adrian Pilatz OBJECTIVE To investigate the influence of commercially available vasoactive drugs on human cavernosal endothelial and fibroblastic cells in vitro, as although corporal fibrosis is a well known side-effect of intracavernosal injection therapy for erectile dysfunction, the possible detrimental effect of these agents on the endothelium lining the cavernosal vascular spaces is uncertain. MATERIALS AND METHODS Cultured primary endothelial (13) and fibroblastic cells (12), obtained from potent patients undergoing penile surgery, were exposed to different physiological dilutions of prostaglandin E1 (PGE1), papaverine/phentolamine or the respective triple-mix of these agents for 30 min. Viable cells were counted and cell metabolic activity measured in these cultures 48 h after drug exposure. RESULTS There was a significant dose-dependent decrease in the viable cell count after exposure to papaverine-containing formulations, probably because of the low pH of this substance. This cytotoxic effect was more pronounced in endothelial than in fibroblastic cells, and was not apparent in the PGE1 groups. The relative increase in cell metabolic activity in cultures affected by a moderate cytotoxic effect indicated a regenerative process. CONCLUSION These comparative results in endothelial and fibroblastic cell cultures suggest that the endothelium rather than the interstitium of the corpus cavernosum is more sensitive to side-effects produced by intracavernosal injection therapy with papaverine. Thus, unfavourable consequences on the function of the endothelial layer might be as important as the risk of interstitial fibrosis. As these effects were not detected for PGE1 this drug should be preferred to papaverine in clinical practice. [source] 3131: Endothelial involvement indicates disease activity in Herpes simplex virus keratitisACTA OPHTHALMOLOGICA, Issue 2010T HILLENAAR Purpose Corneal endotheliitis is a potentially sight-threatening clinical manifestation of herpes simplex virus (HSV) keratitis. Early detection and consequent treatment may prevent development of endothelial decompensation. The goal of this previously published study was to describe the morphological features, frequency, and clinical consequences of endothelial involvement in HSV keratitis as seen by in vivo confocal microscopy (IVCM). Methods We examined both eyes of 250 patients with HSV keratitis by slit-lamp and IVCM. All examinations were assessed for endothelial deviations characteristic of endotheliitis. To determine the specificity, we reviewed our IVCM database for morphologically comparable alterations. This database included 200 healthy volunteers and 1400 patients with various corneal pathologies. The endothelial cell density (ECD) change between the first and last visits of patients with HSV keratitis was evaluated. Results Endotheliitis-specific deviations were detected in 107 of 250 patients with HSV keratitis (43%). Pseudoguttata, enlarged intercellular gaps, infiltration of inflammatory cells into the endothelial layer, loss of defined cell boundaries, spot-like holes, and endothelial denudation disappeared within 3 weeks with appropriate antiviral and anti-inflammatory treatment. Alterations were non-specific for HSV keratitis. Similar alterations were detected in adenoviral, fungal, bacterial, and acanthamoeba keratitis. The HSV affected eyes with endothelial involvement showed a mean ECD decrease of 10.3% per year. Conclusion Endothelial involvement indicates inflammatory activity in HSV keratitis and is associated with irreversible endothelial cell loss. IVCM allows early detection and follow up of endotheliitis-specific alterations. [source] Influence of temperature on corneas stored in culture medium.ACTA OPHTHALMOLOGICA, Issue 1 2003A comparative study using functional, morphological methods Abstract. Purpose:, To investigate the influence of storage temperature on corneal swelling and on endothelial morphology in cultured corneas. Material and methods:, Forty-eight rabbit corneas were separated into four groups of 12. The corneas were stored in culture medium at 37 ° (group 37), 34 ° (group 34), 31 ° (group 31) and 23 ° (room temperature) (group 23), respectively. All the corneas were monitored by weight recordings on days 0, 1, 2, 3, 4 and 7. On day 7, corneas were prepared for scanning electron microscopy and endothelial cell counts were performed. Results:, Lowering the temperature of the culture medium resulted in less swelling. Both temperature and storage time had significant effects on corneal swelling (p < 0.001). On day 7, the observed mean weight increase was 131.2%, 143.0%, 172.5% and 199.7% in groups 23, 31, 34 and 37, respectively. The estimated mean daily weight increase for the corneas were 2.6%, 4.0%, 9.1% and 16.0% in groups 23, 31, 34 and 37, respectively. Scanning electron microscopy showed an intact endothelial layer in all groups after 7 days and there were no statistically significant differences in endothelial counts between groups 23, 31 and 34. In group 37, the cell borders were difficult to distinguish after 7 days and no meaningful count could be performed. Conclusions:, The swelling rate of cultured corneas is significantly less at 23 ° and 31 ° than it is at 34 ° and 37 ° during the first week. This is most likely the result of a greatly increased barrier effect at lower temperatures. Whereas weight recording revealed profound differences between the groups, scanning electron microscopy and endothelial cell counting did not. The results support the hypothesis that storage at 37 ° is not optimal in culturing corneas. Lowering the temperature below body temperature, and even lower than 31 °, results in less corneal swelling. [source] Comparison of the corneal endothelial protective effects of Healon-D and ViscoatCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 4 2009Carolee M Cutler Peck MD MPH Abstract Background:, The use of dispersive ophthalmic viscosurgical devices (OVDs) has been shown to provide significant protection against air bubble damage to the corneal endothelium when compared with cohesive OVDs. We compared the corneal endothelial protective effects of a new dispersive OVD, Healon-D, with Viscoat. Methods:, Healon-D and Viscoat were used in a randomized and masked fashion in the anterior chamber of 40 rabbit eyes during a procedure where ultrasound at 70% continuous energy was delivered for 2 min. Two millilitres of air bubbles were injected into the anterior chamber during the first minute of the procedure on each eye. Corneas were then stained with trypan blue and alizarin red and evaluated via light microscopy for endothelial injury. Both denuding of the endothelial layer, as well as damage to endothelial cells were quantified by using the Evaluation of Posterior Capsule Opacification digital imaging system. Results:, The denuded area for eyes treated with Healon-D and Viscoat were not significantly different (medians of 0.004167and 0.003333, respectively, P = 0.8908). There was no significant difference in the area of endothelial cell damaged (medians of 0.02183 and 0.01433, respectively, P = 0.4565). When the denuded and damaged areas were calculated together, there was also no difference in the total injured area (medians of 0.05817 and 0.05821, respectively, P = 0.5740). Conclusion:, The new dispersive OVD Healon-D is equally as effective as Viscoat in protecting the corneal endothelial layer from denuding and damage from air bubbles during anterior segment surgery. [source] | ||||||||||