iTRAQ-based quantitative proteomic analysis of the anti-apoptotic effect of hyperin, which is mediated by Mcl-1 and Bid, in H2O2-injured EA.hy926 cells.

Endothelial injury has been implicated in the pathogenesis of many cardiovascular diseases, including thrombotic disorders. Hyperin (quercetin-3-O-galactoside), a flavonoid compound and major bioactive component of the medicinal herb Apocynum venetum L., is commonly used to prevent endothelium dysfunction. However, its mode of action remains unclear. To the best of our knowledge, we have for the first time investigated the protective effect hyperin exerts against H2O2-induced injury in human endothelium-derived EA.hy926 cells using isobaric tags for relative and absolute quantitation (iTRAQ)­based quantitative proteomic analysis. The results showed that H2O2 exposure induced alterations in the expression of 250 proteins in the cells. We noted that the expression of 52 proteins associated with processes such as cell apoptosis, cell cycle and cytoskeleton organization, was restored by hyperin treatment. Of the proteins differentially regulated following H2O2 stress, the anti-apoptotic protein, myeloid cell leukemia-1 (Mcl-1), and the pro-apoptotic protein, BH3-interacting domain death agonist (Bid), exhibited marked changes in expression. Hyperin increased Mcl-1 expression and decreased that of Bid in a dose-dependent manner. In addition, flow cytometric analysis and western blot analysis of the apoptosis-related proteins, truncated BID (tBid), cleaved caspase-3, cleaved caspase-9, Fas, FasL and caspase-8, demonstrated that the rate of apoptosis and the pro-apoptotic protein levels were decreased by hyperin pre­treatment. In the present study we demonstrate that hyperin effectively prevents H2O2­induced cell injury by regulating the Mcl­1­ and Bid-mediated anti­apoptotic mechanism, suggesting that hyperin is a potential candidate for use in the treatment of thrombotic diseases.

A biomimetic Schlemm's canal inner wall: A model to study outflow physiology, glaucoma pathology and high-throughput drug screening.

Glaucoma is a disease that damages the optic nerve, frequently leading to blindness. Elevated intraocular pressure (IOP) is the only modifiable risk factor for glaucoma, which is expected to affect 80 million people by 2020, causing bilateral blindness in over 10 million individuals. Because pathological changes to Schlemm's canal (SC) may account for significant resistance to outflow, there is considerable interest in characterizing and evaluating the Schlemm's canal as a target for glaucoma therapeutics. In conventional, two-dimensional culture, human Schlemm's canal (HSC) cells lose spatial, mechanical and biochemical cues, resulting in altered gene expression and cell signaling than observed in vivo, compromising the clinical relevance of data obtained from such systems. Here, we report, for the first time, that 3D culture of HSC cells on microfabricated scaffolds with defined physical and biochemical cues, rescued expression of key HSC markers, VE-cadherin and PECAM1, and mediated pore formation, crucial for the Schlemm's canal regulation of IOP. We demonstrated that following treatment with the glaucopathogenic agent, TGF-ß2, HSC cells undergo an endothelial-mesenchymal transition, which together with the increase in extracellular matrix (ECM) proteins might account for the decrease in outflow facility observed in patients with high TGF-ß2 levels in their aqueous humor. We also demonstrated that unlike 2D cultures, 3D cultures of HSC cells are amenable to gene transfer. Thus, our data imply that 3D culture of HSC cells may be used as a platform to advance our understanding of HSC physiology and pathology and as a model for high-throughput drug and gene screening.

Polydatin Restores Endothelium-Dependent Relaxation in Rat Aorta Rings Impaired by High Glucose: A Novel Insight into the PPARß-NO Signaling Pathway.

Polydatin, a natural component from Polygonum Cuspidatum, has important therapeutic effects on metabolic syndrome. A novel therapeutic strategy using polydatin to improve vascular function has recently been proposed to treat diabetes-related cardiovascular complications. However, the biological role and molecular basis of polydatin's action on vascular endothelial cells (VECs)-mediated vasodilatation under diabetes-related hyperglycemia condition remain elusive. The present study aimed to assess the contribution of polydatin in restoring endothelium-dependent relaxation and to determine the details of its underlying mechanism. By measuring endothelium-dependent relaxation, we found that acetylcholine-induced vasodilation was impaired by elevated glucose (55 mmol/L); however, polydatin (1, 3, 10 µmol/L) could restore the relaxation in a dose-dependent manner. Polydatin could also improve the histological damage to endothelial cells in the thoracic aorta. Polydatin's effects were mediated via promoting the expression of endothelial NO synthase (eNOS), enhancing eNOS activity and decreasing the inducible NOS (iNOS) level, finally resulting in a beneficial increase in NO release, which probably, at least in part, through activation of the PPARß signaling pathway. The results provided a novel insight into polydatin action, via PPARß-NO signaling pathways, in restoring endothelial function in high glucose conditions. The results also indicated the potential utility of polydatin to treat diabetes related cardiovascular diseases.

Beyond organoleptic characteristics: the pharmacological potential of flavonoids and their role in leukocyte migration and in L-selectin and ß2-integrin expression during inflammation.

Flavonoids are compounds responsible for several organoleptic characteristics of plant-derived foods. They are also bioactive compounds with antiinflammatory role. Different mechanisms for this activity have been reported, but their effects on cell migration are not fully understood. In the present study, the role of flavonoids on leukocyte migration in vivo was investigated, using the carrageenan-induced pleurisy model and intravital microscopy in rats. It was found that quercetin (1), rutin (2), flavone (5), apigenin (6) and flavonol (7) reduced cell migration to the pleural cavity and inhibited rolling, adhesion and transmigration. Additionally, flow cytometry assays showed that the in vitro treatment with all compounds (15-60 µM) did not cause cell death and 1 inhibited the cleavage of L-selectin and the ß2-integrin expression, whereas 2 and 7 only inhibited the ß2-integrin expression. Together, data herein presented clearly show the ability of flavonoids to inhibit in vivo neutrophil influx into inflamed tissue, by acting in different mechanisms of neutrophil migration.

Effects of bisphosphonate treatment on circulating osteogenic endothelial progenitor cells in postmenopausal women.

OBJECTIVE: To evaluate whether bisphosphonates modulate vascular calcification by a modification in endothelial progenitor cells (EPCs) coexpressing osteoblastic surface markers and genes. PATIENTS AND METHODS: We performed a double-blind, randomized study of 20 healthy, early postmenopausal women (from February 1, 2008, through July 31, 2008) treated with placebo or risedronate sodium (35 mg/wk) for 4 months. Peripheral blood was collected at baseline and 4 months to determine serum inflammatory markers, osteoprotegerin, and receptor activator of nuclear factor-κB ligand levels and bone turnover markers. Peripheral blood mononuclear cells were stained for EPC surface markers (CD34, CD133, and vascular endothelial growth factor receptor/kinase insert domain receptor) and osteoblast markers (osteocalcin, alkaline phosphatase, and Stro-1). RESULTS: Risedronate treatment resulted in a significant down-regulation of gene sets for osteoblast differentiation and proliferation in EPCs with a trend of decreasing EPCs coexpressing osteocalcin. CONCLUSION: Our findings indicate that bisphosphonate treatment down-regulates the expression of osteogenic genes in EPCs and suggest a possible mechanism by which bisphosphonates may inhibit vascular calcification.

Rosmarinus officinalis L. essential oil inhibits in vivo and in vitro leukocyte migration.

Rosmarinus officinalis L. (Lamiaceae), popularly known as rosemary, is used for food flavoring and in folk medicine as an antispasmodic, analgesic, antirheumatic, diuretic, and antiepileptic agent. Few studies have shown the anti-inflammatory effects of rosemary essential oil (REO). This study evaluated the effects of REO on leukocyte migration through in vivo leukocyte migration and in vitro chemotaxis assay. REO was analyzed by using gas chromatography-mass spectometry, and the main components identified were camphor (27.59%), 1,8-cineole (15.74%), α-pinene (16.58%), and ß-myrcene (10.02%). In rats, administration of REO reduced the number of leukocytes that rolled, adhered, and migrated to the scrotal chamber after carrageenan injection. All doses of REO tested significantly inhibited leukocyte chemotaxis induced by casein. The effects of REO on leukocyte migration highlight an important mechanism of the anti-inflammatory action of rosemary.

[Effects of Xuefu Zhuyu decoction on EPCs function].

OBJECTIVE: To observe the effect on EPCs function by Xuefu Zhuyu Decoction. METHODS: After induced by serial concentrations of Xuefu Zhuyu Decoction-contained serum (XZDCS) and blank serum, EPCs proliferation, migration, adhesion and uptake function were detected by MTT, Boyden chamber, adhesion and uptake of ac-LDL respectively. RESULTS: Compared with the control group, 15% and 10% XZDCS could elevate the cell regeneration for 24 h and 48 h respectively. Both concentrations could improve the EPCs migration and adhesion for all 24, 48, 72 h and uptake of ac-LDL only 48 h. But 10% XZDCS could last effect on uptake of ac-LDL to 72 h and 5% XZDCS converted the inhibition of cell adhesion in the first 24 h to promotion in the next 48 - 72 h. CONCLUSION: Xuefu Zhuyu Decoction could induce EPCs differentiation into EC to angiogenesis by promoting its proliferation, migration, adhesion and uptake function.

Ecklonia cava extracts inhibit lipopolysaccharide induced inflammatory responses in human endothelial cells.

Ecklonia cava (EC) is a brown alga that evidences radical scavenging, bactericidal, tyrosinase inhibitory and protease inhibitory activities. However, the antiinflammatory effects in human endothelial cells and its molecular mechanism remain poorly understood. In this study, we attempted to determine whether pretreatment with EC extracts induce a significant inhibition of antiinflammatory activities in lipopolysaccharide (LPS) induced human endothelial cells. We found that each EC extract inhibits LPS induced barrier permeability, expression of cell adhesion molecules, monocytes adhesion, and transendothelial migration to human endothelial cells. Further studies revealed that EC extracts suppress the production of tumor necrosis factor-alpha (TNF-alpha) and activation of nuclear factor-kappa B (NF-kappaB). Particularly, the antiinflammatory effects of ethyl acetate (EtOAc) and butanol (n-BuOH) extracts were better than those of other extracts. Collectively, these results suggest that EC extracts possess barrier integrity activity, inhibitory activity on cell adhesion and migration to endothelial cells by blocking the activation of NF-kappaB expression and production of TNF-alpha, thereby endorsing its usefulness as therapy for vascular inflammatory diseases.

[Effects of danshensu on function of EPCs which were damaged by Ox-LDL and study its possible mechanism].

OBJECTIVE: To observe the effects of danshensu on function of endothelial progenitor cells (EPCs) from peripheral blood which were damaged by oxidative low density lipoprotein (Ox-LDL). And study its possible mechanism. METHOD: Total mononuclear cells (MNCs) were isolated from peripheral blood by ficoll density gradient centrifugation, and were identified by demonstrating the expression of CD34, VEGFR-2 and AC133 with flow cytometry, to sure that all the cells needed were EPCs. Then the cells were plated on fibronectin-coated culture dishes. After incubation for 7 days, attached cells were collected and divided into three groups: Control group, Ox-LDL group, danshensu intervention group, stimulated with different cencentrations of danshensu (2, 10 and 50 mg x L(-1)), adhesion assay respectively. EPCs adhesion assay were performed by replating those on fibronectin-coated dishes, then adherent cells were counted. And take cell supernate of each group to carry on the SOD, MDA content examination. RESULT: Ox-LDL impaired EPC proliferative and adhesive capacity. In Ox-LDL group, The SOD content obviously drops, the MDA content obviously elevates. After danshensu interventing for 24 h, adhesive EPCs and migratory EPCs were significantly increased. Compared with Ox-LDL group, the SOD content of Danshensu intervention group obviously increased and the MDA content obviously reduced. CONCLUSION: danshensu could improve proliferative and adhesive capacity of EPCs that were impaired by Ox-LDL. The mechanism might relate to the oxidation resistance damage.

Intravenous iron sucrose changes the intraperitoneal homeostasis.

BACKGROUND/AIMS: Intravenous iron infusion is the accepted way of supplementation of that compound in uremic patients. The aim of the study was to evaluate whether this treatment affects intraperitoneal homeostasis in patients on peritoneal dialysis. METHODS: Blood and peritoneal dialysate samples were collected from 10 patients treated with continuous ambulatory peritoneal dialysis who were given 100 mg iron sucrose (IS) intravenously. Systemic and peritoneal permeability as well as transperitoneal transport were studied. The effect of spent dialysate was tested in vitro on human peritoneal mesothelial cells (MCs). RESULTS: Dialysate total iron was increased (+19%, p < 0.01) during intravenous infusion of IS. Immediately after infusion the concentration of 8-OHdG was increased in plasma (+10%, p < 0.01) and in dialysate (+5%, p < 0.05). IS infusion caused a transient decrease in peritoneal permeability to protein (-42%, p < 0.05) and glucose (-30%, p < 0.01) and a reduction in dialysate cell count (-58%, p < 0.05). During the exchange dialysate hyaluronan was increased by 27% (p < 0.01). Spent dialysate, tested ex vivo on cultured MC, induced oxidative stress (+39%, p < 0.01), slowed their proliferation (-20%, p < 0.01), and stimulated MCP-1 synthesis (+46%, p < 0.01). Iron content in MCs exposed to dialysate obtained after IS infusion was increased by 32% (p < 0.01). CONCLUSION: Intravenous infusion of IS causes oxidative stress and inflammation within peritoneal MCs which may impair viability of the peritoneum.

Biologically based myocardial regeneration: is there a role for the surgeon?

PURPOSE OF REVIEW: Despite advances in medical, percutaneous, and surgical treatment, there is an increasing burden of ischemic cardiovascular disease and heart failure. Over the past decade, a large number of preclinical and clinical studies have evaluated various biologic agents to treat these diseases. RECENT FINDINGS: Although the safety and feasibility of growth factor therapy, using vascular endothelial growth factors and fibroblast growth factors, for myocardial angiogenesis has been well established in a number of clinical trials, their ability to induce clinically significant improvements in symptoms remains uncertain. Numerous candidates have been proposed for cell-based therapies to improve myocardial perfusion and function and have demonstrated efficacy in preclinical studies. These cell types include skeletal myoblasts, bone-marrow derived cells, endothelial progenitors, and mesenchymal stem cells. Early clinical trials have demonstrated feasibility of cell harvest and implantation. SUMMARY: Biologic myocardial regeneration is a new and rapidly evolving area for the treatment of cardiovascular disease. Translation of these biologic entities into clinically useful therapeutic agents will require a better mechanistic understanding of their effects on the myocardium and the coronary circulation, optimization of delivery techniques, and systematic evaluation in large, randomized, placebo-controlled studies.

Anti-inflammatory effects of Aloe vera on leukocyte-endothelium interaction in the gastric microcirculation of Helicobacter pylori-infected rats.

This research was aimed to investigate anti-inflammatory effects of Aloe vera on leukocyte-endothelium in the gastric microcirculation of Helicobacter pylori (H. pylori)-infected rats. Thirty-six male Sprague-Dawley rats were divided into 3 groups: control, H. pylori-infected, and A. vera-treated group (200 mg/kg b.w., twice daily). H. pylori-inoculation was induced in the rats by the administration of H. pylori solution. Intravital fluorescence videomicroscopy was used to examine leukocyte adhesion in postcapillary venules on the posterior surface of stomach area on different periods after administration of A. vera. Serum tumor necrosis factor-alpha (TNF-alpha) level was measured in blood collected at the end of experiment by using ELISA technique. The results showed that in H. pylori-infected group on day 8, the leukocyte adhesion was 13.40+/-1.00 cells/100 microm vessel length and the TNF-alpha was 76.76+/-23.18 pg/ml, which increased significantly (p < 0.05), compared with the control group (leukocyte adhesion(control) = 2.54+/-0.6 cells/100 microm vessel length and TNF-alpha(control) = 9.92+/-2.62 pg/ml). Treatment with A. vera reduced the leukocyte adhesion (5.5+/-0.5 cells/100 microm vessel length), and TNF-alpha (26.31+/-6.38 pg/ml) significantly (p < 0.05). In conclusion, H. pylori enhanced leukocyte-endothelium interaction in the posterior stomach area markedly. This enhancement in leukocyte-endothelium interaction could be improved by the treatment of A. vera, associated with reduction in TNF-alpha level.

Anti-angiogenesis therapy can overcome endothelial cell anergy and promote leukocyte-endothelium interactions and infiltration in tumors.

Tumor escape from immunity, as well as the failure of several anti-cancer vaccination and cellular immunotherapy approaches, is suggested to be due to the angiogenesis-mediated suppression of endothelial cell (EC) adhesion molecules involved in leukocyte-vessel wall interactions. We hypothesized that inhibition of angiogenesis would overcome this escape from immunity. We investigated this in vivo by means of intravital microscopy and ex vivo by immunohistochemistry in two mouse tumor models. Angiogenesis inhibitors anginex, endostatin, and angiostatin, and the chemotherapeutic agent paclitaxel were found to significantly stimulate leukocyte-vessel wall interactions by circumvention of EC anergy in vivo, i.e., by the up-regulation of endothelial adhesion molecules in tumor vessels. This was confirmed by in vitro studies of cultured EC at the protein and mRNA levels. The new angiostatic designer peptide anginex was most potent at overcoming EC anergy; the enhanced leukocyte-vessel interactions led to an increase in the numbers of tumor infiltrating leukocytes. While anginex inhibited tumor growth and microvessel density significantly, the amount of infiltrated leukocytes (CD45), as well as the number of CD8+ cytotoxic T lymphocytes, was enhanced markedly. The current results suggest that immunotherapy strategies can be improved by combination with anti-angiogenesis.

Impact of fever-range thermal stress on lymphocyte-endothelial adhesion and lymphocyte trafficking.

The evolutionarily conserved febrile response has been associated with improved survival during infection in endothermic and ectothermic species although its protective mechanism of action is not fully understood. Temperatures within the range of physiologic fever influence multiple parameters of the immune response including lymphocyte proliferation and cytotoxic activity, neutrophil and dendritic cell migration, and production or bioactivity of proinflammatory cytokines. This review focuses on the emerging role of fever-range thermal stress in promoting lymphocyte trafficking to secondary lymphoid organs that are major sites for launching effective immune responses during infection or inflammation. Specific emphasis will be on the molecular basis of thermal control of lymphocyte-endothelial adhesion, a critical checkpoint controlling lymphocyte extravasation, as well as the contribution of interleukin-6 (IL-6) trans-signaling to thermal activities. New results are presented indicating that thermal stimulation of lymphocyte homing potential is evident in evolutionarily distant endothermic vertebrate species. These observations support the view that the evolutionarily conserved febrile response contributes to immune protection and host survival by amplifying lymphocyte access to peripheral lymphoid organs.

Improving surgical wound healing with basic fibroblast growth factor after radiation.

OBJECTIVES/HYPOTHESIS: Delayed wound healing in surgical patients who have received previous irradiation continues to be a significant problem. We investigated whether radiation decreases basic fibroblast growth factor (bFGF) production in skin and whether supplemental bFGF can improve irradiated postsurgical soft tissue healing. STUDY DESIGN: Experimental study in the porcine skin flap model. METHODS: Pigs were subjected to orthovoltage radiation (1,300 cGy). To test whether radiation alters bFGF production in skin, semiquantitation of bFGF message was compared in irradiated and nonirradiated skin by reverse transcription-polymerase chain reaction (RT-PCR). To determine whether supplemental bFGF can improve postsurgical soft tissue healing after radiation, bFGF was given intravenously or intracuticularly preoperatively. To investigate whether additional oxygen tissue levels would modify the effects of supplemental bFGF, one test group received hyperbaric oxygen. Six weeks later, 108 skin flaps (random and arterial) were created in 27 pigs and monitored over 2 weeks. Tissues were analyzed for flap viability, vascularity, endothelial cell apoptosis by caspase-3 activation, and histologic analysis. RESULTS: Radiation statistically increased endothelial cell apoptosis in porcine skin by 650%. Radiation also significantly reduced bFGF message by 75% in porcine skin by RT-PCR analysis. Supplemental intravenous bFGF in irradiated tissue significantly increased skin flap viability by 25% compared with controls (P < .001). Intravenous bFGF also significantly reduced gastrointestinal side effects from irradiation by 50% compared with controls. BFGF treatment induced a trend to decrease endothelial cell apoptosis in irradiated skin, but this was not statistically significant. Histologically, the intravenous bFGF-treated flaps had similar cellularity, fibroblasts, and extracellular acid mucopolysaccharides as controls. When bFGF was administered by intracuticular injection with and without hyperbaric oxygen, skin flap survival and flap vascularity were similar to controls. CONCLUSIONS: Decreased local levels of bFGF in skin may play an important role in the delayed healing of irradiated wounds. Radiation appears to decrease bFGF production by significantly reducing bFGF message in irradiated tissue. Supplemental intravenous bFGF reduced irradiated soft tissue injury and improved random skin flap viability in this porcine model. More studies are needed to investigate the effects of bFGF in the surgical healing of irradiated wounds.

Novel diterpenoids with potent inhibitory activity against endothelium cell HMEC and cytotoxic activities from a well-known TCM plant Daphne genkwa.

Twelve highly oxygenated novel daphnane-type diterpenoids genkwanines A-L (1-12), together with four known diterpenes (13-16), were isolated from the bud of Daphne genkwa, a well-known traditional Chinese medicine (TCM). The new structures were elucidated on the basis of spectral methods, especially 2D NMR spectra (HMQC, HMBC, NOESY). Inhibitory activity against endothelium cell HMEC proliferation and cytotoxic activities against two tumor cell lines were assessed for all the compounds 1-16, and found to be significant and structure related. A number of compounds showed very potent cytotoxic activities against two tumor cell lines at the IC50 levels of 0.15-8.40 microM, and most interestingly, five of the compounds 4, 8, 10, 13, and 14 exhibited strong activity to inhibit the endothelium cell HMEC at the IC50 levels of 2.90-15.0 microM.

Photochemotherapy inhibits angiogenesis and induces apoptosis of endothelial cells in vitro.

BACKGROUND: Photochemotherapy has long been used in the treatment of psoriasis; however, its mechanism has not been completely elucidated. Psoriasis is now regarded as an angiogenesis-related disease. Recent studies indicated that the inhibition of angiogenesis by photochemotherapy could be an underlying mechanism. It was found that photochemotherapy can downregulate the expression of angiogenic factors in keratinocytes. However, the direct effect of photochemotherapy on endothelial cells has not been studied. METHODS: In this study, we determined the effect of photochemotherapy on the proliferation of human microvascular endothelial cells through MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and cell cycle analysis. The migration assay and in vitro tube formation assay were used to investigate the migration properties and tube formation ability of human microvascular endothelial cells after psoralen plus UVA (PUVA) treatment. The apoptosis of endothelial cells elicited by photochemotherapy was also analyzed with fluorescence-activated cell sorting analysis (FACS). RESULTS: UVA (0.8-5.0 J/cm(2)) irradiation with the presence of 8-methoxypsoralen (8-MOP) (300 ng/ml) resulted in a dose-dependent reduction in the cell viabilities of endothelial cells. FACS data showed an accumulation of cells in G0/G1 phase of cell cycle and apoptotic features of cell death after UVA irradiation with psoralen. The migration properties and tube formation ability of endothelial cells were dramatically inhibited by photochemotherapy. CONCLUSION: Our results showed that photochemotherapy inhibits angiogenesis and induces apoptosis of human microvascular endothelial cells in vitro, which may be a possible mechanism of photochemotherapy in the treatment of psoriasis.

Gene expression profiling of the early pulmonary response to hyperoxia in mice.

To identify molecular events occurring during the early response to hyperoxia, we measured changes over time in total lung gene expression in C57BL/6 mice during prolonged exposure to > 95% O2. Specifically, differential gene expression of > 8,734 sequence-verified murine complementary DNAs was analyzed after 0, 8, 24, and 48 h of O2 exposure, with additional genes of interest analyzed at 24 h. Of the 385 genes differentially expressed, hyperoxia increased expression of 175 genes (2.0%) and decreased expression of 210 genes (2.3%). The majority of "classic" antioxidant enzymes, including catalase, MnSOD, and Cu-Zn SOD, showed no change in expression during hyperoxia, with a number of other antioxidant enzymes, including glutathione peroxidase, glutathione-S-Transferase (GST) Pi1, GST mu2, and heme oxygenase-1 showing relatively moderate increases. The exception was the heavy metal-binding protein metallothionein, which increased expression over 7-fold after 48 h of O2. We found no change in the expression of a number of known proinflammatory genes after 24 or 48 h of hyperoxia. A large increase in p21 expression was demonstrated, suggesting overall inhibition of cell cycle progression. Increases of the antiapoptotic gene Bcl-XL were counterbalanced by similar increases of the proapoptotic gene BAX. New findings included significant increases in expression of cysteine-rich protein 61(cyr61) at 48 h, suggesting a potential role for this factor in angiogenesis or remodeling of the extra cellular matrix during recovery from hyperoxia. In addition, downregulation of thrombomodulin expression occurred by 24 h and was further decreased at 48 h. Given the importance of thrombomodulin/thrombin interaction in regulating protein C activity, decreases in thrombomodulin may contribute to activation of the coagulation and inflammatory cascades and development of lung injury with hyperoxia.

[Uremic media affects hemostatic properties of human endothelial cells in culture and increases the production of von Willebrand factor]. / El medio urémico altera las propiedades hemostáticas de células endoteliales humanas en cultivo y aumenta la producción de factor von Willebrand.

We have investigated the ability of serum from uremic patients to modify the thrombogenic properties of the endothelium. The effect of the uremic media on the morphology of ECs, and their resistance to flow was analyzed. The reactivity of the extracellular matrix (ECM) generated by ECs towards normal platelets was evaluated in a parallel-plate perfusion chamber. Exposure of ECs to uremic media resulted in abnormal morphology and signs of accelerated growth. Detachment of ECs exposed to circulating blood was increased when cells had been grown with media supplemented with uremic serum (22% vs 13%). Platelet deposition and formation of aggregates were significantly elevated on ECMs generated in the presence of uremic media (40.23 +/- 6.43% vs 25.42 +/- 2.69%, p < 0.05, n = 5). Immunocytochemical methods detected an enhanced expression of von Willebrand factor antigen on uremic ECMs (uremic 17.1 +/- 4.2% vs control 13.57 +/- 3.98%, p < 0.05) and its mRNA expression in endothelial cells (uremic 213.24 +/- 6.13 vs control 200.77 +/- 7.52, p < 0.05). These results suggest that uremic medium alters endothelial function and impairs the antithrombotic functions of cultured endothelial cells. This effect may contribute to the increased cardiovascular and thrombotic risk reported in ESRD patients.

PCB-induced oxidative stress in endothelial cells: modulation by nutrients.

There is an increasing body of evidence suggesting that exposure to Superfund chemicals may have adverse consequences on many organ systems, as well as carcinogenic and atherogenic effects. This is particularly true for polyhalogenated aromatic hydrocarbons such as the polychlorinated biphenyls (PCBs). The vascular endothelium, which is constantly exposed to blood components including environmental contaminants, is extremely vulnerable to chemical insult as well as necrotic and apoptotic injury. Our recent studies suggest that certain PCBs, especially coplanar PCBs, can compromise normal functions of vascular endothelial cells by activating oxidative stress-sensitive signaling pathways and subsequent proinflammatory events critical in the pathology of atherosclerosis and cardiovascular disease. Our findings suggest that an increase in the level of cellular oxidative stress is a significant event in PCB-mediated endothelial cell dysfunction and that nutrients can modulate PCB-induced oxidative stress and endothelial toxicity. We have demonstrated that the dietary fat linoleic acid, the parent unsaturated fatty acid of the omega-6 family, can increase endothelial dysfunction induced by selected PCBs, probably by contributing to oxidative stress and as the result of the production of toxic metabolites called leukotoxins. The subsequent imbalance in the overall cellular oxidant/antioxidant status can activate oxidative stress- or redoxsensitive transcription factors, which in turn promote gene expression for inflammatory cytokines and adhesion molecules, intensifying the inflammatory response and endothelial cell dysfunction. Our data also suggest that antioxidant nutrients such as vitamin E can protect against endothelial cell damage mediated by PCBs or polyunsaturated dietary fats by interfering with oxidative stress-sensitive and proinflammatory signaling pathways. The concept that nutrition can modify or ameliorate the toxicity of Superfund chemicals is provocative and warrants further study as the implications for human health are significant. The information from such studies could be used to develop dietary recommendations and nutritional interventions for populations at high risk for exposure to PCBs, including communities living near Superfund sites and those exposed via occupation or diet.