Native and decellularized porcine vena cava: Histological analysis and in vitro repopulation.

Apoptosis and underlying mechanisms were evaluated in human umbilical vein endothelial cells (HUVECs), in target tissues of late diabetic vascular complications [human aortic endothelial cells (HAECs) and human retinal endothelial cells (HRECs)], and in endothelial progenitor cells (EPCs) exposed to FFAs, which are elevated in obesity and diabetes. Saturated stearic acid concentration dependently induced apoptosis that could be mediated via reduced membrane fluidity, because both apoptosis and membrane rigidity are counteracted by eicosapentaenoic acid. PUFAs triggered apoptosis at a concentration of 300 micromol/l in HUVECs, HAECs, and EPCs, but not HRECs, and, in contrast to stearic acid, involved caspase-8 activation. PUFA-induced apoptosis, but not stearic acid-induced apoptosis, strictly correlated (P < 0.01) with protein expression of E2F-1 (r = 0.878) and c-myc (r = 0.966). Lack of c-myc expression and activity owing to quiescence or transfection with dominant negative In373-Myc, respectively, renders HUVECs resistant to PUFA-induced apoptosis. Because c-myc is abundant in growing cells only, apoptosis triggered by PUFAs, but not by saturated stearic acid, obviously depends on the growth/proliferation status of the cells. Finally, this study shows that FFA-induced apoptosis depends on the vascular origin and growth/proliferation status of endothelial cells, and that saturated stearic acid-induced apoptosis and PUFA-induced apoptosis are mediated via different mechanisms.

Ce travail resume les etudes qui ont permi la caracterisation de l'action specifique des cytokines sur les cellules endotheliales. Les cytokines agissent aussi sur l'endothelium dans des cas pathologiques cites dans cet expose

Angiogenesis is an essential step for many physiological and pathological processes. Tumor necrosis factor (TNF) superfamily cytokines are increasingly recognized as key modulators of angiogenesis. In this study, we tested whether TNF-related activation-induced cytokine (TRANCE), a new member of the TNF superfamily, possesses angiogenic activity in vitro and in vivo. TRANCE stimulated DNA synthesis, chemotactic motility, and capillary-like tube formation in primary cultured human umbilical vein endothelial cells (HUVECs). Both Matrigel plug assay in mice and chick chorioallantoic membrane assay revealed that TRANCE potently induced neovascularization in vivo. TRANCE had no effect on vascular endothelial growth factor (VEGF) expression in HUVECs and TRANCE-induced angiogenic activity was not suppressed by VEGF-neutralizing antibody, implying that TRANCE-induced angiogenesis may be the result of its direct action on endothelial cells. TRANCE evoked a time- and dose-dependent activation of the mitogen-activated protein kinases ERK1/2 and focal adhesion kinase p125(FAK) in HUVECs, which are closely linked to angiogenesis. These signaling events were blocked by the Src inhibitor PP1 or the phospholipase C (PLC) inhibitor. Furthermore, these inhibitors and the Ca(2+) chelator BAPTA-AM suppressed TRANCE-induced HUVEC migration. These results indicate that the angiogenic activity of TRANCE is mediated through the Src-PLC-Ca(2+) signaling cascade upon receptor engagement in endothelial cells, suggesting the role of TRANCE in neovessel formation under physiological and pathological conditions.

Modulation of adhesion molecule expression on endothelial cells: to be or not to be?

Vascular endothelium, when unperturbed, provides a surface to the blood vessel, which is passive to the development of thrombosis, and potentially adherent blood cells. This characteristic is the quintessence of vascular homeostasis.1 However, endothelial cells (ECs) can undergo apoptosis in vitro in response to a variety of pathophysiological conditions including hypoxia, proinflammatory cytokines, bacterial endotoxins, and atherogenic risk factors such as homocysteine and lipoproteins (reviewed in Stefanec2 and Dimmeler and Zeiher3 ). These cellular perturbations have in common the generation of intracellular reactive oxygen intermediates, referred to as oxidative stress. ECs respond to these adverse conditions by altering their intracellular reduction/oxidization (redox) state and making their ultimate decision between adaptation (survival) and apoptosis (see Figure⇓). Understanding the precise mechanisms controlling such a process is an important component to our knowledge of cardiovascular diseases. In this issue of Circulation Research , Hall et al4 provide novel evidence for a critical role of Ref-1, a redox-sensitive regulator, in affecting EC apoptosis. Ref-1 was cloned as Redox factor, also known as apurinic (apyrimidinic) endonuclease (APE).5 As a ubiquitously expressed multifunctional 36-kDa protein, Ref-1 is involved in the repair of DNA damage as well as in the transcriptional regulation of genes. Its 5′AP-endonuclease functions in base excision repair, and its 3′-diesterase activity removes phosphoglycolate residues from DNA damaged by genotoxic stresses. In addition, Ref-1 is also important for the activation of transcription factors, such as activator protein-1 (AP-1),6 7 nuclear factor-κB (NF-κB),8 p53,9 10 and hypoxia-inducible factor-1α (HIF-1α).11 Activation of transcription factors, which occurs via a redox-based mechanism, pertains to its 6-kDa N-terminal domain. Following its discovery, Xanthoudakis and Curran12 identified Ref-1 as a reductive activator of c-Fos and c-Jun (two major components of AP-1) via a reduction of the conserved cysteine residues …

Transfer of microRNA-486-5p from human endothelial colony forming cell–derived exosomes reduces ischemic kidney injury

Artificial blood vessel: The Holy Grail of peripheral vascular surgery

Cellular and physiological rationale for trimodal combination of chemotherapy, antiangiogenesis and radiotherapy

Receptor Protein Tyrosine Phosphatase μ Regulates the Paracellular Pathway in Human Lung Microvascular Endothelia

From the paradigm shifting observations of Harvey, Malpighi, and van Leeuwenhoek, blood vessels have become recognized as distinct and dynamic tissue entities that merge with the heart to form a closed circulatory system.1 Vessel structures are comprised predominantly of a luminal layer of endothelial cells that is surrounded by some form of basement membrane, and mural cells (pericytes or vascular smooth muscle cells) that make up the vessel wall. In larger more complex vessel structures the vessel wall is composed of a complex interwoven matrix with nerve components. Understanding the cellular and molecular basis for the formation, remodeling, repair, and regeneration of the vasculature have been and continue to be popular areas for investigation. The endothelium has become a particularly scrutinized cell population with the recognition that these cells may play important roles in maintaining vascular homeostasis and in the pathogenesis of a variety of diseases.2 Although it has been known for several decades that some shed or extruded endothelial cells enter the circulation as apparent contaminants in the human blood stream,3 only more recent technologies have permitted the identification of not only senescent sloughed endothelial cells,4 but also endothelial progenitor cells (EPCs), which have been purported to represent a normal component of the formed elements of circulating blood5 and play roles in disease pathogenesis.6–9 Most citations refer to an article published in 1997 in which Asahara and colleagues isolated, characterized, and examined the in vivo function of putative EPCs from human peripheral blood as a major impetus for generating interest in the field.10 This seminal article presented some evidence to consider emergence of a new paradigm for the process of neovascularization in the form of postnatal vasculogenesis. Since publication of that article, interest in circulating endothelial cells, and particularly EPCs, has soared, …

The excessive demand for organ transplants has promoted the development of strategies that increase the supply of immune compatible organs, such as xenotransplantation of genetically modified pig organs and the generation of bioartificial organs. We describe a method for the partial replacement of rat endothelial cells for human endothelial cells in a rat's kidney, obtaining as a final result a rat-human bioartificial kidney. First, in order to maintain parenchymal epithelial cells and selectively eliminate rat endothelial cells, three methods were evaluated in which different solutions were perfused through the renal artery: 0.1% sodium dodecyl sulfate (SDS), 0.01% SDS, and hyperosmolar solutions of sucrose. Then, partially decellularized kidneys were recellularized with human endothelial cells and finally transplanted in an anesthetized rat. The solution of 0.1% SDS achieved the highest vascular decellularization but with high degree of damage in the parenchyma side. On the contrary, 0.01% SDS and hyperosmolar solutions achieved a partial degree of endothelial decellularization. TUNEL assays reveal that hyperosmolar solutions maintained a better epithelial cell viability contrasting with 0.01% SDS. Partially decellularized kidneys were then recellularized with human endothelial cells. Histological analysis showed endothelial cells attached in almost all the vascular bed. Recellularized kidney was transplanted in an anesthetized rat. After surgery, recellularized kidney achieved complete perfusion, and urine was produced for at least 90 min posttransplant. Histological analysis showed endothelial cells attached in almost all the vascular bed. Therefore, endothelial decellularization of grafts and recellularization with human endothelial cells derived from transplant recipients can be a feasible method with the aim to reduce the damage of the grafts.

Tissue Culture of Endothelial Cells.- Culture and identification of large vessel endothelial cells.- Culture of capillary endothelial cells.- Culture of endothelial cells from neural capillaries.- Culture of pulmonary endothelial cells on microcarrier beads.- Construction of an artificial blood vessel wall from cultured endothelial cells.- Determinants of Endothelial and Smooth Muscle Cell Growth.- Growth requirements for bovine aortic endothelium in vitro.- Contact inhibition in the endothelium.- Endothelial cell motility.- Factors which stimulate the growth of human umbilical vein endothelial cells in vitro.- Macrophages, neovascularization, and the growth of vascular cells.- The limited life-span of bovine endothelial cells.- Endothelium, heparin, and the regulation of vascular smooth muscle cell growth.- Morphology of Cultured Endothelial Cells.- Morphology of vascular endothelial cells in culture.- The endothelial cytoskeleton.- Synthesis of Connective Tissue Elements by Endothelial Cells.- Metabolism of thrombospondin and fibronectin by endothelial cells.- Collagen synthesis by endothelial cells in culture.- Sulfated glycosaminoglycans and vascular endothelial cells.- Elastin synthesis by endothelial cells.- Gene mapping using hybrids of human endothelial cells and rodent fibroblasts.- Interactions of Endothelial Cells with the Coagulation and Complement Systems and Formed Elements in Blood.- Properties of plasminogen activators produced by endothelial cells.- Synthesis of Factor VIII by endothelial cells.- Tissue factor activity of cultured human vascular cells.- Activation of Hageman factor by cultured rabbit endothelial cells.- Prostacyclin production by endothelial cells.- Regulation of endothelial cell function by cyclic nucleotides.- Interactions of thrombin, antithrombin III, and Protein C with endothelium.- Viral infection of endothelium and the induction of Fc and C3 receptors.- Adhesive interactions between polymorphonuclear leukocytes and endothelium.- Neutrophil endothelial interactions.- Synthesis of colony stimulating activity by endothelial cells.- Interaction with and Metabolism of Plasma Components by Endothelial Cells.- The metabolism of vasoactive peptides by human endothelial cells.- The metabolism of angiotensin I and bradykinin by endothelial cells.- Metabolism of serotonin and adenosine.- Receptors for insulin and multiplication stimulating activity (MSA) in endothelial cells.- Binding of lipoprotein lipase to cultured endothelial cells.- Role of lipoproteins in the regulation of cultured endothelial cell cholesterol metabolism.- Quantitative aspects of endocytosis in cultured endothelial cells.- Immunologic Aspects of Endothelial Cells.- The alloantigens of endothelial cells.- Accessory cell function of human endothelial cells: presentation of antigen to T cells.- Cell surface markers on endothelial cells: a developmental perspective.- Endothelial Cell and Vasular Prostheses.- Endothelial seeding of vascular prostheses.- Endothelial Cells and Cancer.- Angiogenesis.- Synthesis of collagenase and plasminogen activator by endothelial cells.- In vitro systems for studying the interaction of metastatic tumor cells with endothelial cells and subendothelial basement membranes.

Streptococcus pyogenes expresses the LPXTG motif-containing cell envelope serine protease SpyCep (also called ScpC, PrtS) that degrades and inactivates the major chemoattractant interleukin 8 (IL-8), thereby impairing host neutrophil recruitment. In this study, we identified a novel function of SpyCep: the ability to mediate uptake into primary human endothelial cells. SpyCep triggered its uptake into endothelial cells but not into human epithelial cells originating from pharynx or lung, indicating an endothelial cell-specific uptake mechanism. SpyCep mediated cellular invasion by an endosomal/lysosomal pathway distinct from the caveolae-mediated invasion pathway of S. pyogenes. Recombinant expression and purification of proteolytically active SpyCep and a series of subfragments allowed functional dissection of the domains responsible for endothelial cell invasion and IL-8 degradation. The N-terminal PR domain was sufficient to mediate endothelial cell invasion, whereas for IL-8-degrading activity, the protease domain and the flanking A domain were required. A polyclonal rabbit serum raised against the recombinant protease efficiently blocked the invasion-mediating activity of SpyCep but not its proteolytic function, further indicating that SpyCep-mediated internalization is independent from its enzymatic activity. SpyCep may thus specifically mediate its own uptake as secreted protein into human endothelial cells.

Triple combination of irradiation, chemotherapy (pemetrexed), and VEGFR inhibition (SU5416) in human endothelial and tumor cells

Retroviral vector-mediated transfer and expression of human tissue plasminogen activator gene in human endothelial and vascular smooth muscle cells.