Endothelial Cell Interactions Research Articles

The DPP-4 inhibitor sitagliptin attenuates the progress of atherosclerosis in apolipoprotein-E-knockout mice via AMPK- and MAPK-dependent mechanisms

BackgroundThe dipeptidyl peptidase-4 inhibitor sitagliptin, a new anti-diabetic medicine, is effective in treating type 2 diabetes mellitus by increasing the activation and duration of action of glucagon-like peptide-1. Since atherosclerosis is the main pathological feature of diabetic cardiovascular complications, it is important to investigate the anti-atherosclerotic effect of sitagliptin and explore the relevant mechanisms.MethodsMale apolipoprotein-E-knockout mice were randomly divided into two groups and fed either high-fat diet (HFD) or HFD plus sitagliptin at a concentration of 0.3% for 16 weeks. Body weight, food intake, blood glucose, serum lipids and adhesion molecules were measured. The atherosclerotic plaque area and its histological composition were analyzed using Sudan staining and immunohistochemistry. The expression of inflammatory cytokines (monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-6) and the activation of AMP-activated protein kinase (AMPK) and mitogen-activated protein kinase (MAPK) in the aortas were determined using quantitative polymerase chain reaction and western blot, respectively.ResultsMice treated with sitagliptin developed fewer atherosclerotic plaques than the control group (7.64 ± 1.98% vs 12.91 ± 1.15%, p < 0.001), particularly in the aortic arch and abdominal aorta, where plaques were decreased 1.92- and 2.74-fold, respectively (p < 0.05 and p < 0.01). Sitagliptin significantly reduced the content of collagen fiber in plaques 1.2-fold (p < 0.05). Moreover, sitagliptin significantly reduced the expression of monocyte chemoattractant protein-1 and interleukin-6 in the aorta (p < 0.01 and p < 0.05), as well as the serum levels of soluble vascular cell adhesion molecule-1 and P-selectin (both p < 0.05). In addition, Sitagliptin induced phosphorylation of AMPK and Akt (p < 0.05 and p < 0.01), while suppressed phosphorylation of p38 and extracellular signal-regulated kinase (Erk) 1/2 (p < 0.05 and p < 0.01) in aortas.ConclusionsOur present study indicates that sitagliptin can reduce the area of the atherosclerotic lesion, possibly by regulating the AMPK and MAPK pathways and then reducing leukocyte –endothelial cell interaction and inflammation reactions. These actions are independent of weight loss and glucose-reducing effects.

TNF α‐induced leukocyte–endothelial cell interactions show marked interindividual differences independent of the clinical response to adalimumab

The responses of patients with psoriasis to TNFα-antagonists show interindividual differences. Here, TNFα-incubation induced endothelial adhesion molecules, a prerequisite for leucocyte recruitment to inflamed tissues. Using a standardized flow chamber system equipped with near-confluent endothelial cells and a mobile phase containing human leucocytes, proportions of leucocytes interacting with endothelial cells were remarkably different between individual donors (up to 3.5-fold), regardless of whether the leucocytes originated from patients with psoriasis (n=10) or healthy donors (n=10). Adalimumab abrogated adhesion molecule induction and interactions with leucocytes when present prior to or simultaneously with, but not after exposure of the cultures to TNFα. This pattern was seen similarly with leucocytes from healthy donors (n=4), and patients whose psoriasis responded well to adalimumab (n=5) and non-responders (n=5). Thus, although considerable interindividual differences of leucocyte-endothelial cell interactions were demonstrated ex vivo in a TNFα-governed microenvironment, such differences are not associated with individual responses to treatment with adalimumab in vivo.

Effects of TSH on the function of human umbilical vein endothelial cells

Recent studies have reported that subclinical hypothyroidism (SCH) is associated with atherosclerosis (AS). Thyroid hormone is maintained at normal levels in patients with SCH, whereas TSH is increased. However, the pathogenesis of AS in association with SCH is only partially understood. In addition, endothelial dysfunction plays an important role in the development of AS. The purpose of the present research was to study the direct effect of TSH on human umbilical vein endothelial cells (HUVECs). The expression of some genes associated with endothelial dysfunction after treatment with TSH was evaluated by real-time PCR and western blotting respectively. At first, we showed that the TSH receptor (TSHR) is expressed in HUVECs. We also provide evidence indicating that TSH treatment promotes tumor necrosis factor α-induced endothelial cells interactions by upregulating the expression of the adhesion molecules intercellular adhesion molecule-1. Furthermore, the expression of endothelial nitric oxide synthase (eNOS) and prostacyclin (PGI₂) was significantly attenuated following treatment with TSH in dose- and time-dependent manner. Conversely, the results indicated that TSH upregulated endothelin-1 (ET1) mRNA and protein expression in HUVECs, similar effects were observed for plasminogen activator inhibitor-1 (PAI1) after treatment with various concentrations of TSH. Taken together, these results demonstrate that elevated TSH can promote endothelial dysfunction by altering gene expression in HUVECs.

Reciprocal interactions between tumor and endothelial cells: effects of selective vasopressin V2 receptor peptide agonists

Fil: Garona, Juan. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnologia. Laboratorio de Oncologia Molecular; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

Lipopolysaccharide induces the interactions of breast cancer and endothelial cells via activated monocytes

The adhesion of circulating cancer cells to vascular endothelium is a key step in hematogenous metastasis. Cancer cell-endothelium interactions are mediated by cell adhesion molecules that can also be involved in the arrest of monocytes and other circulating leukocytes on endothelium in inflammation. Static and microfluidic flow adhesion assays as well as flow cytometry were conducted in this study to elucidate the role of monocytes, bacterial lipopolysaccharide (LPS), and histamine in breast cancer cell adhesion to vascular endothelial cells. Tumor necrosis factor-α (TNF-α) released from LPS-treated monocytes triggered the expression of intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells. Histamine augmented the TNF-α effect, leading to a high number of arrested breast cancer cells under both static and shear flow conditions. LPS-treated monocytes were shown to enhance the arrest of breast cancer cells by anchoring the cancer cells to activated endothelial cells. This anchorage was achieved by binding cancer cell ICAM-1 to monocyte β2 integrins and binding endothelial ICAM-1 and VCAM-1 to monocyte β1 and β2 integrins. The results of this study imply that LPS is an important risk factor for cancer metastasis and that the elevated serum level of histamine further increases the risk of LPS-induced cancer metastasis. Preventing bacterial infections is essential in cancer treatment, and it is particularly vital for cancer patients affected by allergy.

Cilostazol inhibits leukocyte–endothelial cell interactions in murine microvessels after transient bilateral common carotid artery occlusion

Leukocyte behavior in the cerebral microvasculature following vessel occlusion has not been fully elucidated. The purpose of this study was to investigate the effects of cilostazol on leukocyte behavior (rolling and adhesion) in murine cerebral microvessels following transient bilateral carotid artery occlusion using intravital fluorescence microscopy. Four groups of mice were assigned: a sham group (n=16); an ischemia (induced by 15-min occlusion of bilateral common carotid arteries) and reperfusion (I/R) group (n=13); I/R+cilostazol (I/R+CZ3mg/kg) group (I/R after oral administration of cilostazol at 3mg/kg) (n=8); and I/R+cilostazol (I/R+CZ30mg/kg) group (I/R after oral administration of cilostazol at 30mg/kg) (n=12). Leukocytes labeled with 0.05% acridine orange were administered intravenously and their behavior was investigated at 3 and 6h after reperfusion. Numbers of rolling or adherent leukocytes were expressed as the count per square millimeter per 30s. Numbers of rolling and adherent leukocytes at 3 and 6h after reperfusion were significantly higher in the I/R group than in the sham or I/R+CZ30mg/kg groups in both pial veins (P<0.05) and pial arteries (P<0.05). Cilostazol (30mg/kg) inhibited leukocyte–endothelial interactions following cerebral ischemia and reperfusion.

Rac-Null Leukocytes Are Associated with Increased Inflammation-Mediated Alveolar Bone Loss

Periodontitis is characterized by altered host-biofilm interactions that result in irreversible inflammation-mediated alveolar bone loss. Genetic and epigenetic factors that predispose to ineffective control of biofilm composition and maintenance of tissue homeostasis are not fully understood. We elucidated how leukocytes affect the course of periodontitis in Rac-null mice. Mouse models of acute gingivitis and periodontitis were used to assess the early inflammatory response and patterns of chronicity leading to loss of alveolar bone due to inflammation in Rac-null mice. Leukocyte margination was differentially impaired in these mice during attachment in conditional Rac1-null (granulocyte/monocyte lineage) mice and during rolling and attachment in Rac2-null (all blood cells) mice. Inflammatory responses to subgingival ligatures, assessed by changes in peripheral blood differential leukocyte numbers, were altered in Rac-null compared with wild-type mice. In response to persistent subgingival ligature-mediated challenge, Rac-null mice had increased loss of alveolar bone with patterns of resorption characteristic of aggressive forms of periodontitis. These findings were partially explained by higher osteoclastic coverage of the bone-periodontal ligament interface in Rac-null compared with wild-type mice. In conclusion, this study demonstrates that leukocyte defects, such asdecreased endothelial margination and tissue recruitment, are rate-limiting steps in the periodontal inflammatory process that lead to more aggressive forms of periodontitis.

Interaction of Endothelial and Smooth Muscle Cells with Cobalt–Chromium Alloy Surfaces Coated with Paclitaxel Deposited Self-Assembled Monolayers

The use of self-assembled monolayers (SAMs) as a polymer-free platform to deliver an antiproliferative drug, paclitaxel (PAT), from a stent material cobalt-chromium (CoCr) alloy has been previously demonstrated. In this study, the interaction of human aortic endothelial cells (ECs) and human aortic smooth muscle cells (SMCs) with CoCr alloy surfaces coated with SAMs- (SAMs-CoCr) and PAT-deposited SAMs (PAT-SAMs-CoCr) was investigated. A polished CoCr with no coatings was used as a control. The viability, proliferation, morphology, and phenotype of ECs and SMCs were investigated on these samples. SAMs-CoCr significantly enhanced the growth of ECs. Also, the ECs were well spreading with its typical morphological features and showed stronger PECAM-1 expression on SAMs-CoCr. This showed that the SAMs-CoCr surface is conducive to endothelialization. For PAT-SAMs-CoCr, although the adhesion of ECs was lower, the cells continued to proliferate with some degree of spreading and limited PECAM-1 expression. For SMCs, a significant decrease in the cell proliferation was observed on SAMs-CoCr when compared with that of Control-CoCr. PAT-SAMs-CoCr showed maximum inhibitory effect on the proliferation of SMCs. Also, the SMCs on PAT-SAMs-CoCr displayed a poorly spread discoid morphology with disarranged α-actin filaments. This showed that the PAT released from the SAMs platform successfully inhibited the growth of SMCs. Thus, this study showed the interaction of ECs and SMCs with SAMs-CoCr and PAT-SAMs-CoCr for potential uses in stents and other cardiovascular medical devices.

On-Chip Evaluation of Neutrophil Activation and Neutrophil–Endothelial Cell Interaction during Neutrophil Chemotaxis

Neutrophils are always surrounded by/interacting with other components of the immune system; however, the current mechanistic understanding of neutrophil function is largely based on how neutrophils respond to a single chemical signal in a simplified environment. Such approaches are unable to recapitulate the in vivo microenvironment; thus, cell behavior may not fully represent the physiological behavior. Herein, we exploit a microfluidic model of the complex in vivo milieu to investigate how cell-cell interactions influence human neutrophil migration and surface marker expression. Neutrophil migration against a bacterially derived chemoattractant (formyl-met-leu-phe, fMLP), with and without preactivation by interleukins (interleukin-2 or interleukin-6), was evaluated in the presence and absence of endothelial support cells. Preactivation by interleukins or interaction with endothelial cells resulted in altered migration rates compared to naïve neutrophils, and migration trajectories deviated from the expected movement toward the fMLP signal. Interestingly, interaction with both interleukins and endothelial cells simultaneously resulted in a slight compensation in the deviation-on endothelial cells, 34.4% of untreated neutrophils moved away from the fMLP signal, while only 15.2 or 22.2% (interleukin-2-or interleukin-6-activated) of preactivated cells moved away from fMLP. Neutrophils interacting with interleukins and/or endothelial cells were still capable of prioritizing the fMLP signal over a competing chemoattractant, leukotriene B4 (LTB4). Fluorescence imaging of individual human neutrophils revealed that neutrophils treated with endothelial-cell-conditioned media showed up-regulation of the surface adhesion molecules cluster determinant 11b and 66b (CD11b and CD66b) upon stimulation. On the other hand, CD11b and CD66b down-regulation was observed in untreated neutrophils. These results leverage single cell analysis to reveal that the interaction between neutrophils and endothelial cells is involved in surface marker regulation and thus chemotaxis of neutrophils. This study brings new knowledge about neutrophil chemotaxis in the context of cell-to-cell communications, yielding both fundamental and therapeutically relevant insight.

New stent surface materials: The impact of polymer-dependent interactions of human endothelial cells, smooth muscle cells, and platelets

Despite the development of new coronary stent technologies, in-stent restenosis and stent thrombosis are still clinically relevant. Interactions of blood and tissue cells with the implanted material may represent an important cause of these side effects. We hypothesize material-dependent interaction of blood and tissue cells. The aim of this study is accordingly to investigate the impact of vascular endothelial cells, smooth muscle cells and platelets with various biodegradable polymers to identify a stent coating or platform material that demonstrates excellent endothelial-cell-supportive and non-thrombogenic properties. Human umbilical venous endothelial cells, human coronary arterial endothelial cells and human coronary arterial smooth muscle cells were cultivated on the surfaces of two established biostable polymers used for drug-eluting stents, namely poly(ethylene-co-vinylacetate) (PEVA) and poly(butyl methacrylate) (PBMA). We compared these polymers to new biodegradable polyesters poly(l-lactide) (PLLA), poly(3-hydroxybutyrate) (P(3HB)), poly(4-hydroxybutyrate) (P(4HB)) and a polymeric blend of PLLA/P(4HB) in a ratio of 78/22% (w/w). Biocompatibility tests were performed under static and dynamic conditions. Measurement of cell proliferation, viability, glycocalix width, eNOS and PECAM-1 mRNA expression revealed strong material dependency among the six polymer samples investigated. Only the polymeric blend of PLLA/P(4HB) achieved excellent endothelial markers of biocompatibility. Data show that PLLA and P(4HB) tend to a more thrombotic response, whereas the polymer blend is characterized by a lower thrombotic potential. These data demonstrate material-dependent endothelialization, smooth muscle cell growth and thrombogenicity. Although polymers such as PEVA and PBMA are already commonly used for vascular implants, they did not sufficiently meet the criteria for biocompatibility. The investigated biodegradable polymeric blend PLLA/P(4HB) evidently represents a promising material for vascular stents and stent coatings.

Revascularization of osteoconductive bone grafts: MSC and endothelial cell interactions

Background and objectives: The interaction of mesenchymal stromal cells (MSC) and endothelial cells (EC) hold a promising perspective for the revascularization of osteoconductive bone grafts in defect regeneration. Co-culture methods of MSC and ES are used to facilitate in vivo bone modeling. However, cell–cell interactions and cell-matrix integrations are not yet fully understood. Following the hypothesis that MSC and EC interactions can lead to an optimized revascularization of osteoconductive bone grafts we analyzed the interactions of MSC and EC in trans-well as well as direct co-culture in vitro.

Static magnetic fields increase tumor microvessel leakiness and improve antitumoral efficacy in combination with paclitaxel

Static magnetic fields (SMF) induce an intratumoral edema possibly by increasing microvessel permeability. The aim of this study was to evaluate the effects of SMF on tumor microvessel permeability and on treatment effects of conventional cytotoxic chemotherapy. Using intravital microscopy in skinfold chamber preparations in A-Mel-3-tumor-bearing hamsters, functional tumor microcirculation, microvessel permeability and leukocyte–endothelial cell interactions were measured under SMF-exposure (587mT). Combining SMF-exposure with paclitaxel-chemotherapy, tumor growth was analyzed.SMF inhibited tumor angiogenesis and increased tumor microvessel permeability significantly. This was not mediated by inflammatory leukocyte–endothelial cell interactions. Further, SMF increased the effectiveness of paclitaxel-chemotherapy significantly.These findings support that SMF possibly open the blood–tumor-barrier to small molecular therapeutics.

Micropatterned Surfaces for the Study of Cancer and Endothelial Cell Interactions with Hyaluronic Acid

AbstractHyaluronic acid (HA) is a glycosaminoglycan component of the extracellular matrix. Studies have shown that various cancers exhibit high levels of HA content, and that an increased amount of HA corresponds to poor patient prognosis. HA has been implicated in cellular interactions that are associated with cancer progression, including cell adhesion, motility, and differentiation. Micropatterned functional HA surfaces were developed to study interactions between cancer cells and HA. The adhesion and migration of cancer cells representing different stages of tumorigenesis were examined. A similar surface patterning approach was used to create HA regions next to fibronectin in two‐ and three‐dimensional settings to visualize and study the interactions between cancer and endothelial cells. The ability to observe the dynamic interactions of cancer cells and angiogenesis within a HA‐rich microenvironment will improve the fundamental understanding of cancer progression and contribute to the development of advanced therapeutic targets.

Cell matrix contact modifies endothelial major histocompatibility complex class II expression in high-glucose environment

Atherosclerosis is a chronic inflammatory disease. Cardiovascular risk factors such as hyperglycemia, hyperlipidemia, and arterial hypertension induce endothelial dysfunction with alterations in endothelial biosecretion and immune behavior. The aim of this study is to elucidate whether glucose-induced modifications of endothelial biosecretory and immune functions are regulated by interactions of endothelial cells (ECs) with their extracellular matrix [ECs plated on polystyrene-coated tissue culture plates (TC-EC) vs. ECs embedded within three-dimensional (3-D) collagen-based matrixes (3D-EC)]. In the absence of glucose, IFN-γ-induced phosphorylation of JAK and STAT proteins and human leukocyte antigen (HLA)-DR expression were lower in 3D-EC compared with TC-EC. Inversely, the expression of suppressor of cytokine signaling proteins (SOCS)-1 and -3 were significantly higher in naïve 3D-EC compared with naïve TC-EC. IFN-γ-induced upregulation of SOCS proteins was further amplified by the 3-D environment. Glucose significantly augmented IFN-γ-dependent signaling pathways in TC-EC. IFN-γ-induced phosphorylation of JAK and STAT proteins as well as HLA-DR expression by ECs in low- and high-glucose medium was significantly lower in 3-D than in two-dimensional environment. Glucose increased SOCS expression in TC-EC and 3D-EC to the same extent, such that expression levels in 3D-EC exceeded SOCS-1 and -3 expression in TC-EC by 1.6-2.5-fold. In conclusion, low- and high-glucose concentrations amplify IFN-γ-induced signaling pathways in TC-EC. Increased SOCS expression raises the threshold for IFN-γ to induce HLA-DR expression in a 3-D environment. This immunoprotective effect is maintained even in states of experimental hyperglycemia.

Enhancement of endothelialisation of coronary stents by laser surface engineering

Coronary stents have been widely used in the treatment of coronary heart disease. However, complications have hampered the long-term success of the device. Bare-metal stents (BMS) have a high rate of restenosis and poor endothelialisation. The drug-eluting stents (DES), although dramatically reduce restenosis, significantly prevent endothelialisation leading to late thrombosis and behave the same way as BMS after drug releasing. Rapid adhesion and growth of endothelial cells on the stent surface is a key process for early vascular healing after coronary stenting which contributes to the reduction of major complications. Surface properties manipulate cell growth and directly determine the success and life-span of the implants. However, the ideal surface properties of coronary stents are not yet fully understood. The objective of this research is to understand how surface micro/nano textures and associated material chemistry changes generated by a laser beam affect the behavior of endothelial cells on bare metal 316L stents. A high power laser beam was applied to modifying the surface properties of 316L coronary stent material and the commercial coronary stents, followed by examination of the adhesion and proliferation of human coronary endothelial cells that were growing on the surfaces. Surface properties were examined by scanning electron microscopy, contact angle measurement, and X-ray photoelectron spectroscopy. A novel surface with combined micro/nano features was created on stent material 316L and coronary stent with a specific surface chemistry. This surface gives rise to a threefold increase in the adhesion and eightfold increase in the proliferation of endothelial cells. Interestingly, such effects were only observed when the surface texture was produced in the nitrogen atmosphere suggesting the importance of the surface chemistry, including the dramatic increase of chromium nitride, for the interaction of endothelial cells with the material surface. This novel surface is also super-hydrophilic with close to zero water/cell culture fluid contact angles and low cytotoxicity. A novel surface created by laser surface-engineering with a combination of defined surface texture and surface chemistry was found beneficial for the improvement of coronary stent endothelialisation. The technology presented here could work with both DES and BMS with added benefit for the improvement of the biocompatibility of current coronary stents.

Marine algal fucoxanthin inhibits the metastatic potential of cancer cells

Metastasis is major cause of malignant cancer-associated mortality. Fucoxanthin has effect on various pharmacological activities including anti-cancer activity. However, the inhibitory effect of fucoxanthin on cancer metastasis remains unclear. Here, we show that fucoxanthin isolated from brown alga Saccharina japonica has anti-metastatic activity. To check anti-metastatic properties of fucoxanthin, in vitro models including assays for invasion, migration, actin fiber organization and cancer cell–endothelial cell interaction were used. Fucoxanthin inhibited the expression and secretion of MMP-9 which plays a critical role in tumor invasion and migration, and also suppressed invasion of highly metastatic B16-F10 melanoma cells as evidenced by transwell invasion assay. In addition, fucoxanthin diminished the expressions of the cell surface glycoprotein CD44 and CXC chemokine receptor-4 (CXCR4) which play roles in migration, invasion and cancer–endothelial cell adhesion. Fucoxanthin markedly suppressed cell migration in wound healing assay and inhibited actin fiber formation. The adhesion of B16-F10 melanoma cells to the endothelial cells was significantly inhibited by fucoxanthin. Moreover, in experimental lung metastasis in vivo assay, fucoxanthin resulted in significant reduction of tumor nodules. Taken together, we demonstrate, for the first time, that fucoxanthin suppresses metastasis of highly metastatic B16-F10 melanoma cells in vitro and in vivo.

Choroid Sprouting Assay: An Ex Vivo Model of Microvascular Angiogenesis

Angiogenesis of the microvasculature is central to the etiology of many diseases including proliferative retinopathy, age-related macular degeneration and cancer. A mouse model of microvascular angiogenesis would be very valuable and enable access to a wide range of genetically manipulated tissues that closely approximate small blood vessel growth in vivo. Vascular endothelial cells cultured in vitro are widely used, however, isolating pure vascular murine endothelial cells is technically challenging. A microvascular mouse explant model that is robust, quantitative and can be reproduced without difficulty would overcome these limitations. Here we characterized and optimized for reproducibility an organotypic microvascular angiogenesis mouse and rat model from the choroid, a microvascular bed in the posterior of eye. The choroidal tissues from C57BL/6J and 129S6/SvEvTac mice and Sprague Dawley rats were isolated and incubated in Matrigel. Vascular sprouting was comparable between choroid samples obtained from different animals of the same genetic background. The sprouting area, normalized to controls, was highly reproducible between independent experiments. We developed a semi-automated macro in ImageJ software to allow for more efficient quantification of sprouting area. Isolated choroid explants responded to manipulation of the external environment while maintaining the local interactions of endothelial cells with neighboring cells, including pericytes and macrophages as evidenced by immunohistochemistry and fluorescence-activated cell sorting (FACS) analysis. This reproducible ex vivo angiogenesis assay can be used to evaluate angiogenic potential of pharmacologic compounds on microvessels and can take advantage of genetically manipulated mouse tissue for microvascular disease research.

The use of plasma-activated covalent attachment of early domains of tropoelastin to enhance vascular compatibility of surfaces

All current metallic vascular prostheses, including stents, exhibit suboptimal biocompatibility. Improving the re-endothelialization and reducing the thrombogenicity of these devices would substantially improve their clinical efficacy. Tropoelastin (TE), the soluble precursor of elastin, mediates favorable endothelial cell interactions while having low thrombogenicity. Here we show that constructs of TE corresponding to the first 10 (“N10”) and first 18 (“N18”) N-terminal domains of the molecule facilitate endothelial cell attachment and proliferation equivalent to the performance of full-length TE. This N-terminal ability contrasts with the known role of the C-terminus of TE in facilitating cell attachment, particularly of fibroblasts. When immobilized on a plasma-activated coating (“PAC”), N10 and N18 retained their bioactivity and endothelial cell interactive properties, demonstrating attachment and proliferation equivalent to full-length TE. In whole blood assays, both N10 and N18 maintained the low thrombogenicity of PAC. Furthermore, these N-terminal constructs displayed far greater resistance to protease degradation by blood serine proteases kallikrein and thrombin than did full-length TE. When immobilized onto a PAC surface, these shorter constructs form a modified metal interface to establish a platform technology for biologically compatible, implantable cardiovascular devices.

Biomarkers in Pulmonary Hypertension

Pulmonary hypertension (PH) is a hemodynamic condition that has a poor prognosis and can lead to right-sided heart failure. It may result from common diseases such as left-sided heart or lung disease or may present as the rare entity of idiopathic pulmonary arterial hypertension. Biomarkers that specifically indicate the pathologic mechanism, the severity of the disease, and the treatment response would be ideal tools for the management of PH. In this review, markers related to heart failure, inflammation, hemostasis, remodeling, and endothelial cell-smooth muscle cell interaction are discussed, and their limitations are emphasized. Anemia, hypocarbia, elevated uric acid, and C-reactive protein levels are unspecific markers of disease severity. Brain natriuretic peptide and N-terminal fragment of pro-brain natriuretic peptide have been recommended in current guidelines, whereas other prognostic markers, such as growth differentiation factor-15, osteopontin, and red cell distribution width, are emerging. Chemokines of the CC family and matrix metalloproteases have been linked to the vascular pathologic mechanisms, and new markers such as apelin have been described. Circulating endothelial and progenitor cells have received much attention as markers of disease activity, but with controversial findings. A lack of standards for cell isolation and characterization methods and differences in the pathologic mechanisms of the investigated patients may have contributed to the discrepancies. In conclusion, although several promising markers have been identified over the past few years, the development of more specific markers, standardization, and prospective validation are warranted.

C-Kit/c-Kit ligand interaction of bone marrow endothelial progenitor cells is influenced in a cigarette smoke extract-induced emphysema model

ABSTRACTBackground: Smoking causes lung endothelial cell apoptosis and emphysema. Derived from bone marrow, circulating endothelial progenitor cells (EPCs) maintain vascular integrity by replacing and repairing damaged endothelial cells. Smoking influences the number of circulating EPCs. Recruitment of EPCs from bone marrow to peripheral blood depends on the interaction of c-Kit/soluble c-Kit ligand (sKitL). We hypothesized that smoking might influence c-Kit(+) EPCs/sKitL interaction in bone marrow in the development of smoking-related emphysema. In this study, we used a cigarette smoke extract (CSE)-induced emphysema model. Methods: Mice were injected intraperitoneally with PBS/CSE and sacrificed at day 28. Lung function and pathology of lung tissue were measured to characterize the model. Expressions of c-Kit in the lung tissue were assayed. Bone marrow cells were isolated by red blood cell lysis. EPCs/c-Kit(+) EPCs in nonred blood cells were analyzed by flow cytometry. Expressions of KitL and MMP-9, and activity MMP-9 in bone marrow were measured. Results: Our data demonstrated that gene and protein expressions of c-Kit were decreased in the lung tissue in this model. Compared with the control group, the number of bone marrow nonred blood cells was unchanged following CSE treatment, while the depletion of bone marrow EPCs/c-Kit(+) EPCs was significant. The level of sKitL was reduced in the bone marrow in the model. The reduction of sKitL was associated with deregulated KitL expression and decreased MMP-9 activity. Conclusions: The interaction between c-Kit and sKitL in bone marrow EPCs, a critical step in endothelial repair, is negatively affected in a CSE-induced emphysema model.