Tumor cell invasion in blood vessels assessed by immunohistochemistry is related to decreased survival in patients with bladder cancer treated with radical cystectomy.

BACKGROUND: Lymphovascular invasion (VI) is an established prognostic marker for many cancers including bladder cancer. There is a paucity of data regarding whether the prognostic significance of lymphatic invasion (LVI) differs from blood vessel invasion (BVI). The aim was to examine LVI and BVI separately using immunohistochemistry (IHC), and investigate their associations with clinicopathological characteristics and prognosis. A secondary aim was to compare the use of IHC with assessing VI on standard HAS (hematoxylin-azophloxine-saffron) sections without IHC. METHODS: A retrospective, population -based series of 292 invasive bladder cancers treated with radical cystectomy (RC) with curative intent at Vestfold Hospital Trust, Norway were reviewed. Traditional histopathological markers and VI based on HAS sections were recorded. Dual staining using D2-40/CD31 antibodies was performed on one selected tumor block for each case. RESULTS: The frequency of LVI and BVI was 32 and 28%, respectively. BVI was associated with features such as higher pathological stages, positive regional lymph nodes, bladder neck involvement and metastatic disease whereas LVI showed weaker or no associations. Both BVI and LVI independently predicted regional lymph node metastases, LVI being the slightly stronger factor. BVI, not LVI predicted higher pathological stages. BVI showed reduced recurrence free (RFS) and disease specific (DSS) survival in uni-and multivariable analyses, whereas LVI did not. On HAS sections, VI was found in 31% of the cases. By IHC, 51% were positive, corresponding to a 64% increased sensitivity in detecting VI. VI assessed without IHC was significantly associated with RFS and DSS in univariable but not multivariable analysis. CONCLUSIONS: Our findings indicate that BVI is strongly associated with more aggressive tumor features. BVI was an independent prognostic factor in contrast to LVI. Furthermore, IHC increases VI sensitivity compared to HAS.

Vascular architectural patterns in clear cell renal cell carcinoma and clear cell papillary renal cell carcinoma.

Renal cell carcinomas (RCC) are well-vascularized tumors. Although clear cell RCC (CCRCC) show a characteristic vascular network, some cases show overlapping features with other RCC. We aimed to evaluate vascular architectural patterns, microvessel density (MVD), and endothelial cell density (ECD) in CCRCC compared to clear cell papillary RCC (ccpRCC). Thirty-four RCC (17 CCRCC and 17 ccpRCC) were included in the study. CD34 was used to evaluate vascular architectural patterns by microscopic estimation in all cases. CD34, ERG, and Bioquant Osteo 2019 Imaging Analysis Software were used to evaluate MVD and ECD in 17 CCRCC and 15 ccpRCC. Mean MVD was 526.63 in CCRCC vs. 426.18 in ccpRCC (p = 0.16); mean ECD was 937.50 in CCRCC vs. 1060.21 in ccpRCC (p = 0.25). CD34 highlighted four distinct vascular architectural patterns: pseudoacinar, Golgi-like, lacunae, and scattered. Lacunae and pseudoacinar was the most frequent combination in CCRCC; lacunae and Golgi-like was the predominant combination among ccpRCC. Pseudoacinar was most extensive in CCRCC and least in ccpRCC; Golgi-like was predominant in ccpRCC and uncommon in CCRCC. The extent of pseudoacinar and Golgi-like vascular architectural patterns was significantly different between CCRCC and ccpRCC (p < 0.05). Pathologists acquainted with these different vascular architectural patterns may utilize them as an additional tool in the distinction of CCRCC from ccpRCC.

Absence of lymphatic vessels in non-functioning bleb capsules of glaucoma drainage devices.

PURPOSE: To evaluate the presence and appearance of blood and lymphatic vessels in non-functioning bleb capsules of glaucoma drainage devices (GDD). MATERIALS AND METHODS: Non-functioning (n=14) GDD-bleb capsules of 12 patients were analyzed by immunohistochemistry for blood vessels (CD31, vascular endothelium), lymphatic vessels (lymphatic vessel endothelial hyaluronan receptor-1 [LYVE-1] and podoplanin) and macrophages (CD68). RESULTS: CD31+++ blood vessels and CD68+ macrophages were detected in the outer layer of all specimens. LYVE-1 immunoreactivity was registered in single non-endothelial cells in 8 out of 14 (57%) bleb capsule specimens. Podoplanin-immunoreactivity was detected in all cases, located in cells and profiles of the collagen tissue network of the outer and/or the inner capsule layer. However, a colocalization of LYVE-1 and podoplanin as evidence for lymphatic vessels was not detected. CONCLUSIONS: We demonstrate the presence of blood-vessels but absence of lymphatic vessels in non-functioning bleb capsules after GDD-implantation. While the absence of lymphatic vessels might indicate a possible reason for drainage device failure, this needs to be confirmed in upcoming studies, including animal experiments.

Enhanced vascularization and biocompatibility of rat pancreatic decellularized scaffolds loaded with platelet-rich plasma.

The ultimate goal of pancreatic tissue engineering is to create a long-lived substitute organ to treat diabetes. However, the lack of neovascularization and the occurrence of immune response limit the efficacy of tissue-engineered pancreas after in vivo transplantation. Platelet-rich plasma (PRP) is an autologous platelet concentrate containing a large number of growth factors and immunoregulatory factors. The aim of this study was to evaluate rat pancreatic decellularized scaffold (PDS) loaded with PRP for vascularization, host inflammatory response and macrophage polarization in an animal model. The study results indicated that compared to PDS, PRP-loading PDS exhibited the enhanced mechanical properties and released growth factors in a slow and sustained manner to supplement the loss of growth factors during decellularization. In vitro, human umbilical vein endothelial cells (HUVECs) were seeded in PDS and PRP-loading PDS, and cultured in the circular perfusion system. When compared with PDS, PRP-loading PDS significantly promoted the colonization, proliferation and pro-angiogenic genes expression of cells on scaffolds. In vivo, PDS loaded with PRP then re-endothelialized with HUVECs were implanted subcutaneously in rats, which enhanced the angiogenesis of scaffolds, inhibited the host inflammatory response, and induced the polarization dominated by pro-regenerative M2 macrophages that also facilitated tissue vascular regeneration. Thus, the re-endothelialized PRP-loading PDS may represent a promising bioengineered pancreas with sustained vascularization and excellent biocompatibility.

Integrin ß4 Is an Effective and Efficient Marker in Synchronously Highlighting Lymphatic and Blood Vascular Invasion, and Perineural Aggression in Malignancy.

Lymphovascular invasion (LVI) and perineural invasion (PNI) are 2 important pathologic parameters and need to be accurately assessed in multiple malignancies. Integrin ß4, a member of the integrin family, has been reported to be positively expressed in vascular endothelia, peripheral nerves, and a collection of epithelia. However, little is known about the effectiveness of ß4 immunostaining on the recognition of LVI and PNI. Herein, we explored the applicability of ß4 immunostaining in stomach, thyroid, and breast cancers. Parallel immunostaining of D2-40, CD34, and S-100 was performed as controls for lymphatic endothelia, vascular endothelia, and neural fibers, respectively. The results demonstrated that ß4 concurrently stained the lymphatic and vascular endothelia, and the peripheral nerves. Both LVI and PNI were clearly and accurately outlined by ß4 immunostaining. ß4 was also expressed in the majority of tumor cells, enabling recognition of LVI and PNI encroached by small tumor clusters. In contrast to D2-40 and CD34, ß4 staining was not observed in stromal cells, and therefore it facilitated differentiation between the shrinkage cleft and LVI. According to our results, ß4 staining strikingly increased the diagnostic accuracy and interobserver concordance for LVI and PNI compared with hematoxylin and eosin staining alone. Finally, the applicability of ß4 was confirmed in 9 other types of malignancies, including cancers of the colon, prostate, esophagus, lung, kidney, uterus, tongue, bladder, and liver. Collectively, ß4 is a reliable marker for synchronous detection and diagnosis of LVI and PNI.

Artificial small-diameter blood vessels: materials, fabrication, surface modification, mechanical properties, and bioactive functionalities.

Cardiovascular diseases, especially ones involving narrowed or blocked blood vessels with diameters smaller than 6 millimeters, are the leading cause of death globally. Vascular grafts have been used in bypass surgery to replace damaged native blood vessels for treating severe cardio- and peripheral vascular diseases. However, autologous replacement grafts are not often available due to prior harvesting or the patient's health. Furthermore, autologous harvesting causes secondary injury to the patient at the harvest site. Therefore, artificial blood vessels have been widely investigated in the last several decades. In this review, the progress and potential outlook of small-diameter blood vessels (SDBVs) engineered in vitro are highlighted and summarized, including material selection and development, fabrication techniques, surface modification, mechanical properties, and bioactive functionalities. Several kinds of natural and synthetic polymers for artificial SDBVs are presented here. Commonly used fabrication techniques, such as extrusion and expansion, electrospinning, thermally induced phase separation (TIPS), braiding, 3D printing, hydrogel tubing, gas foaming, and a combination of these methods, are analyzed and compared. Different surface modification methods, such as physical immobilization, surface adsorption, plasma treatment, and chemical immobilization, are investigated and are compared here as well. Mechanical requirements of SDBVs are also reviewed for long-term service. In vitro biological functions of artificial blood vessels, including oxygen consumption, nitric oxide (NO) production, shear stress response, leukocyte adhesion, and anticoagulation, are also discussed. Finally, we draw conclusions regarding current challenges and attempts to identify future directions for the optimal combination of materials, fabrication methods, surface modifications, and biofunctionalities. We hope that this review can assist with the design, fabrication, and application of SDBVs engineered in vitro and promote future advancements in this emerging research field.

Interobserver Agreement in Vascular Invasion Scoring and the Added Value of Immunohistochemistry for Vascular Markers to Predict Disease Relapse in Stage I Testicular Nonseminomas.

Vascular invasion has been identified as an informative risk factor for relapse in stage I testicular nonseminomas, used to tailor treatment. We investigated interobserver agreement in vascular invasion reporting and studied the potential additional value of immunohistochemistry for vascular markers for predicting relapse. Patients (n=52) with stage I testicular nonseminomas undergoing surveillance (1993-2006) were included (median follow-up of 66 mo). Two formalin-fixed paraffin-embedded blocks with >1 cm tissue and tumor/normal parenchyma interface were stained with hematoxylin and eosin and CD31, FVIII, and D2-40. Slides were assessed by 3 independent testicular germ cell tumor-dedicated pathologists, and agreement was assessed using Cohen κ statistic. Sensitivity, specificity, and accuracy of vascular invasion scoring in predicting relapse were calculated. Agreement among testicular germ cell tumor-dedicated pathologists was moderate (κ=0.49 to 0.54), as was performance in predicting disease relapse (particularly, specificity of 86%). Immunohistochemistry increased overall sensitivity (71%), but decreased specificity (71%) in predicting relapse. All patients (n=8) with both blood and lymphatic vascular invasion developed a relapse. In multivariable analysis (including age, tumor size, rete testis invasion, and serum tumor markers), only vascular invasion had an independent impact in predicting relapse. Assessment of vascular invasion by testicular germ cell tumor-dedicated pathologists is good and is clinically meaningful, predicting disease relapse. Immunohistochemistry for vascular markers improves sensitivity of detecting disease relapse and allows for the identification of high-risk patients with both blood and lymphatic vascular invasion simultaneously, potentially of interest for tailored chemotherapy.

Engineering the vasculature of decellularized rat kidney scaffolds using human induced pluripotent stem cell-derived endothelial cells.

Generating new kidneys using tissue engineering technologies is an innovative strategy for overcoming the shortage of donor organs for transplantation. Here we report how to efficiently engineer the kidney vasculature of decellularized rat kidney scaffolds by using human induced pluripotent stem cell (hiPSCs)-derived endothelial cells (hiPSC-ECs). In vitro, hiPSC-ECs responded to flow stress by acquiring an alignment orientation, and attached to and proliferated on the acellular kidney sections, maintaining their phenotype. The hiPSC-ECs were able to self-organize into chimeric kidney organoids to form vessel-like structures. Ex vivo infusion of hiPSC-ECs through the renal artery and vein of acellular kidneys resulted in the uniform distribution of the cells in all the vasculature compartments, from glomerular capillaries to peritubular capillaries and small vessels. Ultrastructural analysis of repopulated scaffolds through transmission and scanning electron microscopy demonstrated the presence of continuously distributed cells along the vessel wall, which was also confirmed by 3D reconstruction of z-stack images showing the continuity of endothelial cell coverage inside the vessels. Notably, the detection of fenestrae in the endothelium of glomerular capillaries but not in the vascular capillaries was clear evidence of site-specific endothelial cell specialisation.

Carbon debris and fiber cleaving: Effects on potassium-titanyl-phosphate laser energy and chorioallantoic membrane model vessel coagulation.

OBJECTIVES/HYPOTHESIS: Photoangiolytic precision afforded by the 532-nm potassium-titanyl-phosphate (KTP) laser relies on predictable energy delivery. Inadequate energy output can cause vessel rupture, and excessive energy can cause thermal damage. The quality of the cleaved surface and carbon deposits from ablated tissue are two factors that could negatively impact fiber performance. The effects of these on energy output and blood vessel coagulation were assessed using a chorioallantoic membrane (CAM) model. STUDY DESIGN: Comparative analysis. METHODS: Laser fibers with carbon debris, optimal fiber cleaving, and suboptimal cleaving were inspected at three times magnification, and the light dispersion pattern of each fiber was rated. The average energy output from consecutive pulses through each fiber configuration was recorded. The effect of these fiber conditions on clinical efficacy was estimated by measuring vessel coagulation versus rupture in the CAM model. Repeated measures analysis of variance compared results. RESULTS: Carbon debris and suboptimal cleaving resulted in decreased energy output in comparison to optimal cleaving ([-Δ244 mJ, d = 4.31, P < .001] and [-Δ195 mJ, d = 6.04, P < .001]). Optimal cleaving resulted in immediate coagulation of vessels. Fibers with suboptimal cleaving and carbon debris had unpredictable outcomes, requiring multiple pulses for coagulation or causing vessel rupture. CONCLUSIONS: KTP laser fiber function is significantly affected by fiber tip condition. Carbon debris and suboptimal cleaving create significant attenuation of energy, which results in an unpredictable angiolytic effect, as demonstrated by increased vessel rupture in the CAM model. Optimal recleaving of KTP laser fibers restores prior energy output and predictable coagulation. Care should be taken to avoid carbon debris on laser-fiber tips and to cleave fibers properly. LEVEL OF EVIDENCE: NA Laryngoscope, 129:2244-2248, 2019.

Electrochemical fabrication of a biomimetic elastin-containing bi-layered scaffold for vascular tissue engineering.

Biomimetic tissue-engineered vascular grafts (TEVGs) have immense potential to replace diseased small-diameter arteries (<4 mm) for the treatment of cardiovascular diseases. However, biomimetic approaches developed thus far only partially recapitulate the physicochemical properties of the native vessel. While it is feasible to fabricate scaffolds that are compositionally similar to native vessels (collagen and insoluble elastic matrix) using freeze-drying, these scaffolds do not mimic the aligned topography of collagen and elastic fibers found in native vessels. Extrusion-based scaffolds exhibit anisotropic collagen orientation but these scaffolds are compositionally dissimilar (cannot incorporate insoluble elastic matrix). In this study, an electrochemical fabrication technique was employed to develop a biomimetic elastin-containing bi-layered collagen scaffold which is compositionally and structurally similar to native vessels and the effect of insoluble elastin incorporation on scaffold mechanics and smooth muscle cell (SMC) response was investigated. Further, the functionality of human umbilical vein endothelial cells (HUVECs) on the scaffold lumen surface was assessed via immunofluorescence. Results showed that incorporation of insoluble elastin maintained the overall collagen alignment within electrochemically aligned collagen (ELAC) fibers and this underlying aligned topography can direct cellular orientation. Ring test results showed that circumferential orientation of ELAC fibers significantly improved scaffold mechanics. Real-time PCR revealed that the expression of α-smooth muscle actin (Acta2) and myosin heavy chain (MyhII) was significantly higher on elastin containing scaffolds suggesting that the presence of insoluble elastin can promote contractility in SMCs. Further, mechanical properties of the scaffolds significantly improved post-culture indicating the presence of a mature cell-synthesized and remodeled matrix. Finally, HUVECs expressed functional markers on collagen lumen scaffolds. In conclusion, electrochemical fabrication is a viable method for the generation of a functional biomimetic TEVG with the potential to be used in bypass surgery.

Image segmentation by graph cut for radiation images of small animal blood vessels.

Synchrotron radiation (SR) based X-ray imaging is an attractive method for analyzing biomedical structure. However, despite its many advantages, there are few gold standards in image processing methods, especially in segmentation. Image segmentation is an essential step in medical imaging for image analysis and three-dimensional reconstruction. Although there are many algorithms for image segmentation, a decisive method does not exist in SR X-ray imagery, because of a lack of data. This study focused on finding a suitable algorithm for image segmentation in high-resolution medical imaging. In this study, we used following four algorithms to segment blood vessel of mouse; interactive graph cuts algorithm, which segments an image using fast min-cut/max-flow algorithm to solve global solution, binary partition tree algorithm, which uses an interactive method creating tree nodes to segment an image by using splitting and merging an image, seeded region growing algorithm, which performs segmentation by connecting similar pixel value, simple interactive object extraction, which generates color signature for segmentation based on color model of an image.

Measurement of tissue optical properties in the context of tissue optical clearing.

Nowadays, dynamically developing optical (photonic) technologies play an ever-increasing role in medicine. Their adequate and effective implementation in diagnostics, surgery, and therapy needs reliable data on optical properties of human tissues, including skin. This paper presents an overview of recent results on the measurements and control of tissue optical properties. The issues reported comprise a brief review of optical properties of biological tissues and efficacy of optical clearing (OC) method in application to monitoring of diabetic complications and visualization of blood vessels and microcirculation using a number of optical imaging technologies, including spectroscopic, optical coherence tomography, and polarization- and speckle-based ones. Molecular modeling of immersion OC of skin and specific technique of OC of adipose tissue by its heating and photodynamic treatment are also discussed.

Recent Progress in the Development of Microfluidic Vascular Models.

The blood vessel is part of the circulatory system, and systemic circulation provides the blood supply to all tissues. Arteries are pathways through which the blood is carried, and the capillaries have a key role in material exchange to maintain the tissue environment. Blood vessels have structures appropriate for their functions, and their sizes and cell types are different. In this review, we introduced recent studies of the microfluidic vascular models. The model structures are classified mainly as poly(dimethylsiloxane) and hydrogel microchannels and self-assembled networks. Basic phenomena and functions were realized in vascular models, including fluid shear stress, cell strain, interstitial flow, endothelial permeation, angiogenesis, and thrombosis. In some models, endothelial cells were co-cultured with smooth muscle cells, pericytes, and fibroblasts in an extracellular matrix. Examples of vascular models involving the brain, lung, liver, kidney, placenta, and cancer were also introduced.

Micropatterning as a tool to identify regulatory triggers and kinetics of actin-mediated endothelial mechanosensing.

Developmental processes, such as angiogenesis, are associated with a constant remodeling of the actin cytoskeleton in response to different mechanical stimuli. The mechanosensitive transcription factors MRTF-A (MKL1) and YAP (also known as YAP1) are important mediators of this challenging adaptation process. However, it is as yet unknown whether both pathways respond in an identical or in a divergent manner to a given microenvironmental guidance cue. Here, we use a micropatterning approach to dissect single aspects of cellular behavior in a spatiotemporally controllable setting. Using the exemplary process of angiogenesis, we show that cell-cell contacts and adhesive surface area are shared regulatory parameters of MRTF and YAP on rigid 2D surfaces. By analyzing MRTF and YAP under laminar flow conditions and during cell migration on dumbbell-shaped microstructures, we demonstrate that they exhibit different translocation kinetics. In conclusion, our work promotes the application of micropatterning techniques as a cell biological tool to study mechanosensitive signaling in the context of angiogenesis.

An Extensive Description of the Peptidomic Repertoire of the Hen Egg Yolk Plasma.

Hen egg is a raw material widely used for the preparation of food,  pharmaceutical and cosmetoceutical products. Dedicated proteomic studies were accomplished on eggshell membrane, egg white, and yolk, identifying the most abundant proteins. No similar peptidomic studies have been performed so far. Only preliminary investigations on bioactive peptides in egg fractions and digestates were accomplished through functional screening assays, characterizing antioxidant, antibacterial, antiviral, immunomodulatory, and antihypertensive preparations and isolated components. This study fills this gap and provides a comprehensive picture of the peptides present in the yolk plasma of different hen egg types after 24 and 264 h of laying, taking advantage of a procedure based on a two-step fractionation followed by combined MALDI-TOF-TOF-MS- and nanoLC-ESI-Q-Orbitrap-MS/MS-based analysis. Six hundred and twenty-eight peptides were characterized as deriving from the proteolytic processing of larger protein components after the physiological action of chicken chymotrypsin-like and pepsin-like enzymes. Structural details on their post-translational modifications were also provided. Identified peptides were subjected to bioinformatic analysis and further compared with available data from the literature, ascertaining 198 peptides associable with putative antihypertensive, antimicrobial, anticancer, antiviral, antibiofilm, anorectic, calcium-binding, and anti-inflammatory activities. This analysis was often confirmative of previous experimental evidence on functional properties of unfractionated preparations or isolated molecules. These results further emphasize the bioactive action of yolk-derived peptides as related to egg consumption, and the potential use of these molecules as additive ingredients in the preparation of functional foods and cosmetics.

GeLC-MS: A Sample Preparation Method for Proteomics Analysis of Minimal Amount of Tissue.

Application of various proteomics methodologies have been implemented for the global and targeted proteome analysis of many different types of biological samples such as tissue, urine, plasma, serum, blood, and cell lines. Among the aforementioned biological samples, tissue has an exceptional role into clinical research and practice. Disease initiation and progression is usually located at the tissue level of different organs, making the analysis of this material very important for the understanding of the disease pathophysiology. Despite the significant advances in the mass spectrometry instrumentation, tissue proteomics still faces several challenges mainly due to increased sample complexity and heterogeneity. However, the most prominent challenge is attributed to the invasive procedure of tissue sampling which restricts the availability of fresh frozen tissue to minimal amounts and limited number of samples. Application of GeLC-MS sample preparation protocol for tissue proteomics analysis can greatly facilitate making up for these difficulties. In this chapter, a step by step guide for the proteomics analysis of minute amounts of tissue samples using the GeLC-MS sample preparation protocol, as applied by our group in the analysis of multiple different types of tissues (vessels, kidney, bladder, prostate, heart) is provided.

Construction of Antithrombotic Tissue-Engineered Blood Vessel via Reduced Graphene Oxide Based Dual-Enzyme Biomimetic Cascade.

Thrombosis is one of the biggest obstacles in the clinical application of small-diameter tissue-engineered blood vessels (TEBVs). The implantation of an unmodified TEBV will lead to platelet aggregation and further activation of the coagulation cascade, in which the high concentration of adenosine diphosphate (ADP) that is released by platelets plays an important role. Inspired by the phenomenon that endothelial cells continuously generate endogenous antiplatelet substances via enzymatic reactions, we designed a reduced graphene oxide (RGO) based dual-enzyme biomimetic cascade to successively convert ADP into adenosine monophosphate (AMP) and AMP into adenosine. We used RGO as a support and bound apyrase and 5'-nucleotidase (5'-NT) on the surface of RGO through covalent bonds, and then, we modified the surface of the collagen-coated decellularized vascular matrix with the RGO-enzyme complexes, in which RGO functions as a platform with a large open surface area and minimal diffusion barriers for substrates/products to integrate two catalytic systems for cascading reactions. The experimental results demonstrate that the two enzymes can synergistically catalyze procoagulant ADP into anticoagulant AMP and adenosine successively under physiological conditions, thus reducing the concentration of ADP. AMP and adenosine can weaken or even reverse the platelet aggregation induced by ADP, thereby inhibiting thrombosis. Adenosine can also accelerate the endothelialization of TEBVs by regulating cellular energy metabolism and optimizing the microenvironment, thus ensuring the antithrombotic function and patency of TEBVs even after the RGO-enzyme complex loses its activity.

The Distribution of Transplanted Umbilical Cord Mesenchymal Stem Cells in Large Blood Vessel of Experimental Design With Traumatic Brain Injury.

The authors aim to track the distribution of human umbilical cord mesenchymal stem cells (MSCs) in large blood vessel of traumatic brain injury -rats through immunohistochemical method and small animal imaging system. After green fluorescent protein (GFP) gene was transfected into 293T cell, virus was packaged and MSCs were transfected. Mesenchymal stem cells containing GFP were transplanted into brain ventricle of rats when the infection rate reaches 95%. The immunohistochemical and small animal imaging system was used to detect the distribution of MSCs in large blood vessels of rats. Mesenchymal stem cells could be observed in large vessels with positive GFP expression 10 days after transplantation, while control groups (normal group and traumatic brain injury group) have negative GFP expression. The vascular endothelial growth factor in transplantation group was higher than that in control groups. The in vivo imaging showed obvious distribution of MSCs in the blood vessels of rats, while no MSCs could be seen in control groups. The intravascular migration and homing of MSCs could be seen in rats received MSCs transplantation, and new angiogenesis could be seen in MSCs-transplanted blood vessels.

Effect of Polypeptides on Cell Proliferation and Apoptosis during Aging.

Polypeptide complexes derived from the bronchi, blood vessels, muscles, kidneys, ovaries, testes, and retina stimulated the processes of cell renewal in organotypic cultures of the corresponding organs of young and old animals. A correlation between the intensity of regeneration and animal' age was revealed. The polypeptide complexes reduced the expression of apoptotic factors p53 and caspase 3 and increased the expression of proliferation protein Ki-67. These results provide the basis for further study of the polypeptide complexes as stimulators of regenerative processes in different tissues during ageing.

Perivascular extracellular matrix hydrogels mimic native matrix microarchitecture and promote angiogenesis via basic fibroblast growth factor.

Extracellular matrix (ECM)-derived bioscaffolds have been shown to elicit tissue repair through retention of bioactive signals. Given that the adventitia of large blood vessels is a richly vascularized microenvironment, we hypothesized that perivascular ECM contains bioactive signals that influence cells of blood vessel lineages. ECM bioscaffolds were derived from decellularized human and porcine aortic adventitia (hAdv and pAdv, respectively) and then shown have minimal DNA content and retain elastin and collagen proteins. Hydrogel formulations of hAdv and pAdv ECM bioscaffolds exhibited gelation kinetics similar to ECM hydrogels derived from porcine small intestinal submucosa (pSIS). hAdv and pAdv ECM hydrogels displayed thinner, less undulated, and fibrous microarchitecture reminiscent of native adventitia, with slight differences in ultrastructure visible in comparison to pSIS ECM hydrogels. Pepsin-digested pAdv and pSIS ECM bioscaffolds increased proliferation of human adventitia-derived endothelial cells and this effect was mediated in part by basic fibroblast growth factor (FGF2). Human endothelial cells cultured on Matrigel substrates formed more numerous and longer tube-like structures when supplemented with pAdv ECM bioscaffolds, and FGF2 mediated this matrix signaling. ECM bioscaffolds derived from pAdv promoted FGF2-dependent in vivo angiogenesis in the chick chorioallantoic membrane model. Using an angiogenesis-focused protein array, we detected 55 angiogenesis-related proteins, including FGF2 in hAdv, pAdv and pSIS ECMs. Interestingly, 19 of these factors were less abundant in ECMs bioscaffolds derived from aneurysmal specimens of human aorta when compared with non-aneurysmal (normal) specimens. This study reveals that Adv ECM hydrogels recapitulate matrix fiber microarchitecture of native adventitia, and retain angiogenesis-related actors and bioactive properties such as FGF2 signaling capable of influencing processes important for angiogenesis. This work supports the use of Adv ECM bioscaffolds for both discovery biology and potential translation towards microvascular regeneration in clinical applications.