The effect of Wi-Fi on elastic and collagen fibres in the blood vessel wall of the chorioallantoic membrane

See related article, pages 1057–1064 The formation of the cardiovascular system starts in the mouse embryo at approximately embryonic day (E)7.0 to E7.5. The first blood vessels in the extraembryonic membranes, the major intraembryonic vessels, and the heart form by vasculogenesis, the in situ differentiation of mesodermal cells that give rise to “blood-islands.” The latter are composed of hemangioblasts, the common precursors of endothelial and blood cells. Hemangioblasts situated in the lumen of the blood islands will further differentiate into hematocytoblasts, the precursors of all 3 lineages of blood cells. In contrast, hemangioblasts lining the walls of the blood islands will give rise to angioblasts that form endothelial cells.1 Migrating angioblasts from the proximal lateral mesoderm assemble symmetrically at the lateral sides of the embryo to establish 2 preendocardial tubes. They fuse to give rise to the primordial heart.2 While vasculogenesis is still proceeding, the uniform blood islands begin to remodel to a network of large and small vessels by the process of angiogenesis, preferentially intussusceptive microvascular growth.3,4 Gene expression and targeting studies have identified vascular endothelial growth factor and its 2 receptors, KDR/flk-1 and flt-1, as critical for the formation and early remodeling of the blood islands. Vascular endothelial growth factor is produced by endodermal and mesodermal cells at the onset of hemangioblast formation, whereas its receptors are expressed in the future endothelial cells lining the blood islands.5 Flk-1−/− embryos lack blood islands throughout the embryo and yolk sac.6 In flt-1−/− embryos, blood islands do not properly remodel but form large blood channels.7 Inactivation of a single vascular endothelial growth factor allele caused multiple embryonic malformations including the heart, rudimentary dorsal aortae, and a reduced number of blood cells.8,9 All deletions were lethal between days E8.5 and E11 to …

Lung Morphometry, Collagen and Elastin Content: Changes after Hyperoxic Exposure in Preterm Rabbits

The chicken chorioallantoic membrane (CAM) is used as a model in tests of angiogenesis, the biocompatibility of materials as well as tumor invasive potential. To assess the properties of CAM tissue, the localization of leptin receptor in the CAM, and the mRNA expression of two leptin receptor isoforms, estrogen receptors (ERα and ERβ) and caspases (-1 and -3) in the CAM on embryonic days 12 (E12), 15 (E15) and 18 (E18) were investigated. The leptin receptor was immunolocalized in each structure of the CAM (chorionic epithelium, allantoic epithelium, mesodermal layer and the walls of blood vessels) and did not change among analyzed stages of embryonic development (E12, E15 and E18) and between sexes. Expression of mRNA of genes encoding leptin and estrogen receptors as well as caspases was detected in the CAM of female and male chicken embryos at all three analysed stages of development. The relative mRNA expression of the long form of leptin receptor exceeded that of its short isoform. The mRNA expression of ERβ was significantly higher than ERα as well as caspase-3 in comparison with caspase-1. There were no differences in mRNA expression of these genes between sexes and among analyzed developmental days. The results indicate that the CAM is a target tissue for leptin as well as for estrogens and that CAM development is partially regulated by caspase-1 and caspase-3 dependent cell death. These results should be taken into consideration in studies in which the CAM is used as an experimental model.

Background: Oral Submucous Fibrosis (OSMF) is a collagen related disorder seen in habitual betel-quid chewers. This is a high risk precancerous condition which clinically presents vertical palpable fibrous bands in buccal mucosa, generalized fibrosis of oral soft tissues with restricted mouth opening. Present study was undertaken to ascertain the changes occurring in collagen type I & III and elastic fibres in OSMF in relation to orientation, density and thickness. Study Methods: The study was performed on 15 cases in each group such as Stage I OSMF, Stage II OSMF, Stage III OSMF and normal oral mucosa (NOM). The biopsied samples were routinely processed for paraffin embedding; stained with Hematoxylin and Eosin as well as special stains like Masson's Trichrome (MT), Verhoeff Van Gieson (VVG) and Picrosirius red (PSR) and examined under light and polarized microscope respectively. MT stain demonstrated all types of collagen fibers collectively while PSR stain under polarized microscopy demonstrated collagen type I and type III separately with enhanced birefringence. VVG stain demonstrated very fine black colored elastic fibers, thus changes taken place could be accurately ascertained with progression of the disease. Results: Change in the orientation of collagen type I has been observed in stage II and stage III of OSMF from haphazard to parallel in relation to surface epithelium, while no change was noted in type III collagen fibres as well as elastic fibres in any stage of OSMF, and remained haphazardly arranged. Increased density of type I collagen was observed with increasing stage of OSMF from moderately dense to dense, while decrease in density of type III collagen was noticed in stage III than in stage II OSMF from moderately dense to sparse. The density of elastic fibres was decreasing from dense in stage I to sparse in stage III. Thickness of collagen type I was increasing with increasing grades while type III collagen and elastic fibres remained unchanged. Conclusion: The alterations in orientation, density and thickness of collagen fibres and density of elastic fibres in various grades of OSMF contribute to the clinical presentation of trismus with progression of the disease. Key Words: Collagen type I, Collagen type III, Elastic fibres, Masson's trichrome stain, Verhoeff Van Gieson stain, Picrosirius red stain

This study delves into possible mechanisms underlying the stimulating influence of UC-MSCs transplantation on functional and structural recovery of ischemic skeletal muscles. Limb ischemia was created in Sprague-Dawley rats by excision of femoral and popliteal arteries. Allogeneic rat PKH26-labeled UC-MSCs were administered by direct intramuscular injection. Animals of experimental group responded to the transplantation by improvement in their locomotor function as assessed by the rotarod performance test on day 9 and 29 after transplantation. Histomorphometric analysis showed that relative area of the lesions in the experimental group was significantly smaller than in the control group at all time points during the observation. Calculated densities of microcirculation vessels within the lesions were significantly higher in the experimental group than in the control group on day 10 after transplantation. Only a part of the transplanted allogeneic UC-MSCs survived within the ischemic muscle tissue, and a considerable portion of these surviving cells were found alongside the VEGF-producing preserved muscle fibers. The PKH26 label was not found within the walls of capillaries or larger blood vessels. The administration of allogeneic UC-MSCs significantly increased the proportion of M2 macrophages, exhibiting proangiogenic and anti-inflammatory properties, for at least 10 days following the transplantation.

Guidance molecules have attracted interest by demonstration that they regulate patterning of the blood vascular system during development. However, their significance during postnatal angiogenesis has remained unknown. Here, we demonstrate that endothelial cells of human malignant brain tumors also express guidance molecules, such as EphB4 and its ligand ephrinB2. To study their function, EphB4 variants were overexpressed in blood vessels of tumor xenografts. Our studies revealed that EphB4 acts as a negative regulator of blood vessel branching and vascular network formation, switching the vascularization program from sprouting angiogenesis to circumferential vessel growth. In parallel, EphB4 reduces the permeability of the tumor vascular system via activation of the angiopoietin-1/Tie2 system at the endothelium/pericyte interface. Furthermore, overexpression of EphB4 variants in blood vessels during (i) vascularization of non-neoplastic cell grafts and (ii) retinal vascularization revealed that these functions of EphB4 apply to postnatal, non-neoplastic angiogenesis in general. This implies that both neoplastic and non-neoplastic vascularization is driven not only by a vascular initiation program but also by a vascular patterning program mediated by guidance molecules.

A method for studying atherosclerotic plaques on the walls of large blood vessels is described. The method is based on a study of raw data of intravascular optical coherence tomography (IOCT). Identification of fat constituents, calcium, cholesterol crystals, macrophage clusters, blood clots, etc. within the areas of atherosclerotic lesions of blood vessels is based on the study of two parameters only. The intensity of the A-scan interference signal is the first parameter, and the biomechanical properties (primarily Young's modulus) are the second analyzed parameter. The pulse wave is used as the least traumatic deforming effect. The magnitude of the deforming effect in blood vessels is calculated using averaging of the blood pressure differences. This data is acquired using an invasive pressure probe. Structural IOCT-images corresponding to the moments of systole and diastole are selected from the sequence of raw data. Both IOCT-images are segmented and classified by signal intensity. Primarily, identification of segments is based on reference data of the optical properties of the atherosclerotic plaques’ components. The segments with similar geometrical locations and signal intensity are grouped into pairs. The centroids are calculated for all segments. The absolute displacements of the segments are estimated by the displacements of the centroids. The area of deformation is considered to be equal to the scanning area of the applied intravascular probe. The dimensions of the deformable area for the set of segments of two analyzed images are calculated with respect to the coordinate axes and then averaged. The biomechanical properties of the segments are calculated according to classical formulas and are used to update values of the primary identification of the structural components of atherosclerotic plaques. Information about the geometric characteristics and internal structure of atherosclerotic plaques are used to identify their properties and current stability.

The structural and catalytic requirements for neutrophil MMP-9 proenzyme (proMMP-9) to induce angiogenesis were investigated using a quantitative angiogenesis model based on grafting of collagen onplants onto the chorioallantoic membrane of chick embryos. Both physiological activation of neutrophil proMMP-9 and proteolytic activity of the generated MMP-9 enzyme were critically dependent on the tissue inhibitor of metalloproteinase (TIMP)-free status of the zymogen. The presence of an intact active site and hemopexin domain were required for full angiogenesis-inducing activity of the MMP-9 enzyme. Timed additions of TIMP-1 to the onplants containing TIMP-free neutrophil proMMP-9 indicated that in vivo activation of the zymogen occurred during the first 24 h after grafting. Within the onplant tissue, MMP-9 activation was accompanied by proteolytic modifications of fibrillar collagen and an influx of host proteins, the rate of which depended on the TIMP-free status of the zymogen. By quantifying the levels of host angiogenic factors, we demonstrated that basic fibroblast growth factor (FGF-2) was a major cytokine becoming bioavailable in the onplant tissue undergoing a neutrophil proMMP-9-mediated angiogenic switch. Inhibition of angiogenesis with specific function-blocking antibodies further indicated an involvement of a FGF-2/FGFR-2 pathway in neutrophil proMMP-9-induced angiogenesis. The enhanced angiogenesis catalyzed by neutrophil MMP-9 appears to evoke also a localized, low threshold level vascular endothelial growth factor (VEGF)/VEGFR-2 pathway, likely functioning in the formation and/or stabilization of blood vessels. That neutrophil proMMP-9, unencumbered by TIMP-1, directly mediates FGF-2-dependent angiogenesis was also demonstrated in our quantitative mouse angiogenesis model employing subcutaneous collagen implants, thus implicating the novel TIMP-free MMP-9/FGF-2/FGFR-2 pathway in proMMP-9-induced angiogenesis in a mammalian setting.

In order to map the extracellular or membrane proteome associated with the vasculature and the stroma in an embryonic organism in vivo, we developed a biotinylation technique for chicken embryo and combined it with mass spectrometry and bioinformatic analysis. We also applied this procedure to implanted tumors growing on the chorioallantoic membrane or after the induction of granulation tissue. Membrane and extracellular matrix proteins were the most abundant components identified. Relative quantitative analysis revealed differential protein expression patterns in several tissues. Through a bioinformatic approach, we determined endothelial cell protein expression signatures, which allowed us to identify several proteins not yet reported to be associated with endothelial cells or the vasculature. This is the first study reported so far that applies in vivo biotinylation, in combination with robust label-free quantitative proteomics approaches and bioinformatic analysis, to an embryonic organism. It also provides the first description of the vascular and matrix proteome of the embryo that might constitute the starting point for further developments.

This study has goals of examining whether pre-eclampsia may lead to an increase of elastic tissue fibers in blood vessel walls of placental stem villi or whether there are differences in the thickness of blood vessel walls within these villi when compared to normotensive pregnant women. Non-infarcted placental tissue samples from 28 participants with uncomplicated pregnancies and 26 patients with pre-eclampsia were obtained. After routine histological procedures, the sections were processed either for conventional Verhoeff staining for the demonstration of elastic fiber system. Paraffine sections from placenta biopsies prepared for light microscopic examination were gathered. In uncomplicated pregnancies, terminal villi blood vessels were observed with no stained elastic tissue fibers in most areas. In the pre-eclampsia pregnancy of human placenta, the elastic fibers significiantly increased in terminal villi blood vessel walls which were dark in color, using Verhoeff’s tissue stain, when comparing with the uncomplicated pregnancy group. Our results indicate that an increase of elastic tissue fibers in blood vessels of placental stem villus and terminal villi, and also an increase of wall thickness during pre-eclampsia.

Engineering of an elastic large muscular vessel wall with pulsatile stimulation in bioreactor

В настоящее время в клинической практике с целью коррекции пресбиопии применяются несколько видов интракорнеальных линз (ИКЛ) [5]. Актуальным представляется поиск биосовместимого материала, инертного по отношению к ткани стромы роговицы, в присутствии которого клетки стромы роговицы обладают сниженной тенденцией к адгезии и пролиферации. В исследовании были использованы 2 различных полимера на основе гидроксиэтилметакрилата (ГЭМА) и олигоуретанметакрилата (ОУМА), потенциально пригодных для их изготовления. Цель работы - изучение ex vivo реакции роговицы донора-трупа на имплантацию интракорнеальных линз, изготовленных из полимерных материалов на основе ГЭМА и ОУМА. Методика. Для моделирования процесса интракорнеальной имплантации использовали глазные яблоки доноров-трупов (ГЯДТ). Сформированы 4 экспериментальные группы (по 3 глазных яблока в каждой): 1-я - опытная группа «ГЭМА»; 2-я - опытная группа «ОУМА», 3-я - группа сравнения «Хронический контроль» и 4-я - группа сравнения «Острый контроль». По окончании исследования оценивали морфологическими методами наличие на изучаемых поверхностях клеток волокнистых соединительнотканных элементов, степень деформации ИКЛ. Качественно в опытных и контрольных группах оценивали изображения полученные различными методами - флуоресцентной микроскопии и сканирующей электронной микроскопии. Результаты. Согласно результатам исследования ex vivo изучаемые линзы не имели тенденции к инкапсуляции. По окончании исследования на поверхности ИКЛ в опытных группах обнаруживались адгезировавшие клеточно-волокнистые элементы, которые, однако не образовывали единого монослоя ни в группе ГЭМА, ни в группе ОУМА, в связи с чем можно предположить наличие у исследуемых полимерных материалов минимальных адгезивных свойств. Заключение. Результаты экспериментально-морфологического исследования ex vivo позволяют заключить, что изделия из данных полимерных материалов (ГЭМА и ОУМА) биологически совместимы, представляются потенциально пригодными для интракорнеальной имплантации и могут быть рекомендованы к дальнейшему изучению в клинических условиях. Currently, several types of intracorneal lenses (ICL) are used in clinical practice to correct presbyopia. It seems relevant to search for a biocompatible material that is inert with respect to corneal stromal tissue, in the presence of which corneal stromal cells would less tend to adhesion and proliferation. This study used two different polymers based on hydroxyethylmethacrylate (HEMA) and olygouretanmethacrylate (OUMA). The aim was to study the ex vivo reaction of cadaver corneas to implantation of ICLs made of polymeric materials based on HEMA and OUMA. Methods. The process of intracorneal implantation was modeled on eyeballs from cadaver donors (EBCD). Four experimental groups were formed: 1) «HEMA» experimental group (3 EBCD); 2) «OUMA» experimental group (3 EBCD); 3) «chronic control» comparison group (4 EBCD); and 4) «acute control» comparison group (3 EBCD). The presence of fibrous connective tissue elements on the studied surfaces and the degree of ICL deformation were evaluated at the end of the study. Images obtained with different methods, fluorescence microscopy and scanning electron microscopy, were qualitatively compared in the experimental and control groups. Results. According to results of the ex vivo study, the developed lenses did not tend to encapsulate. In experimental groups, cellular-fibrous elements were found on the surface of the ICL. However, there was no monolayer of cells or fibrous elements on the ICL in experimental groups, which suggested that the adhesive properties of studied polymeric materials are minimal. Conclusions. Results of this experimental ex vivo study showed that ICLs made of either polymeric material (HEMA or OUMA) are potentially suitable for intracorneal implantation and can be recommended for further study in clinical conditions due to their biological compatibility.

Aging of the elastic and collagen fibers in the human cervical interspinous ligaments

The study investigated the relationship between the histological compositions of the tricuspid, pulmonary, mitral, and aortic valves, and age. All 85 fresh human hearts were obtained with an age range between 20 and 90years. The central area of the valves was conducted to analyze the density of collagen and elastic fibers by using an image analysis program. Neural network function in MATLAB was used for classification data and accuracy test of the age predictive model. Overall, a gradual increase in the density of collagen and elastic fibers was demonstrated with age in all valve types. The pulmonary valve cusps had the least density of collagen and elastic contents, whereas the most dense of collagen was found in the mitral leaflets. A similarity was noted for the elastic fibers in the tricuspid, mitral, and aortic valves. The highest correlation between the collagen (r = 0.629) and elastic fibers (r = 0.713) and age was found in the noncoronary cusp of the aortic valve. The established predictive equations using collagen and elastic fibers in the noncoronary cusp provided the standard error of ± 14.0 and 12.5years, respectively. A 60.9% of accuracy was found in all age groups using collagen, while accuracy in elastic fibers showed 70.0% in the classification process using the neural networks. The current study provided additional data regarding age-associated changes of collagen and elastic fibers in the human heart valves in Thais and the benefits and application in age forensic identification.

ABSTRACTPurpose: To assess changes in lymphatic vessels, collagen, and elastic fiber structure in excised tissues with dermatochalasis (DC). Methods: In this prospective histopathological study, 70 upper eyelid skins of 35 patients operated on for dermatochalasis were compared with 10 eyelid skins of 10 patients operated on for other diagnoses. In histopathological examination, the two groups of patients were compared with respect to number of lymphatic vessels, largest lymphatic vessel diameter, number of elastic fibers, number of macrophages, edema between collagen fibers, and depth of stromal collagen bed. Results: As compared to the control group, the study group had a significantly greater number of dilated lymphatic vessels (p = 0.0001), largest lymphatic vessel diameter (p = 0.02), depth of stromal collagen bed (p = 0.0001), edema space between collagen fibers (p = 0.0001), elastic fiber density (p = 0.0001), and number of macrophages (p = 0.001). Conclusion: According to the results of the present study, in addition to an increase in the diameter and number of lymphatic vessels, a reduction in elastic fibers that are essential for the structure and function of lymphatic system, disarrangement in collagen fibers, stromal edema, and increased number of macrophages play a role in the development of dermatochalasis.