An antibody that targets cell-surface glucose-regulated protein-78 inhibits expression of inflammatory cytokines and plasminogen activator inhibitors by macrophages.

Glucose-regulated protein-78 (Grp78) is an endoplasmic reticulum chaperone, which is secreted by cells and associates with cell surfaces, where it functions as a receptor for activated α2 -macroglobulin (α2 M) and tissue-type plasminogen activator (tPA). In macrophages, α2 M and tPA also bind to the transmembrane receptor, LDL receptor-related protein-1 (LRP1), activating a cell-signaling receptor assembly that includes the NMDA receptor (NMDA-R) to suppress innate immunity. Herein, we demonstrate that an antibody targeting Grp78 (N88) inhibits NFκB activation and expression of proinflammatory cytokines in bone marrow-derived macrophages (BMDMs) treated with the toll-like receptor-4 (TLR4) ligand, lipopolysaccharide, or with agonists that activate TLR2, TLR7, or TLR9. Pharmacologic inhibition of the NMDA-R or deletion of the gene encoding LRP1 (Lrp1) in BMDMs neutralizes the activity of N88. The fibrinolysis protease inhibitor, plasminogen activator inhibitor-1 (PAI1), has been implicated in diverse diseases including metabolic syndrome, cardiovascular disease, and type 2 diabetes. Deletion of Lrp1 independently increased expression of PAI1 and PAI2 in BMDMs, as did treatment of wild-type BMDMs with TLR agonists. tPA, α2 M, and N88 inhibited expression of PAI1 and PAI2 in BMDMs treated with TLR-activating agents. Inhibiting Src family kinases blocked the ability of both N88 and tPA to function as anti-inflammatory agents, suggesting that the cell-signaling pathway activated by tPA and N88, downstream of LRP1 and the NMDA-R, may be equivalent. We conclude that targeting cell-surface Grp78 may be effective in suppressing innate immunity by a mechanism that requires LRP1 and the NMDA-R.

The Multifaceted Role of Plasminogen in Cancer.

Fibrinolytic factors like plasminogen, tissue-type plasminogen activator (tPA), and urokinase plasminogen activator (uPA) dissolve clots. Though mere extracellular-matrix-degrading enzymes, fibrinolytic factors interfere with many processes during primary cancer growth and metastasis. Their many receptors give them access to cellular functions that tumor cells have widely exploited to promote tumor cell survival, growth, and metastatic abilities. They give cancer cells tools to ensure their own survival by interfering with the signaling pathways involved in senescence, anoikis, and autophagy. They can also directly promote primary tumor growth and metastasis, and endow tumor cells with mechanisms to evade myelosuppression, thus acquiring drug resistance. In this review, recent studies on the role fibrinolytic factors play in metastasis and controlling cell-death-associated processes are presented, along with studies that describe how cancer cells have exploited plasminogen receptors to escape myelosuppression.

The Effect of Sequential Compression Devices on Fibrinolysis in Plastic Surgery Outpatients: A Randomized Trial.

BACKGROUND: Sequential compression devices are often considered a mainstay of prophylaxis against deep venous thromboses in surgical patients. The devices are believed to produce a milking action on the deep veins to prevent venous stasis. A systemic fibrinolytic effect has also been proposed, adding a second mechanism of action. The plasma levels of tissue plasminogen activator and plasminogen activator inhibitor-1 reflect fibrinolytic activity. METHODS: A randomized trial was conducted among 50 consecutive plastic surgery outpatients undergoing cosmetic surgery performed by the author under total intravenous anesthesia and without paralysis. Patients were randomized to receive calf-length sequential compression devices or no sequential compression devices during surgery. Blood samples were obtained from the upper extremity preoperatively and at hourly intervals until the patient was discharged from the postanesthesia care unit. Tissue plasminogen activator and plasminogen activator inhibitor-1 levels were measured. Ultrasound surveillance was used in all patients. There was no outside funding for the study. RESULTS: All patients agreed to participate (inclusion rate, 100 percent). No patient developed clinical signs or ultrasound evidence of a deep venous thrombosis. There were no significant changes in tissue plasminogen activator levels or plasminogen activator inhibitor-1 levels from the preoperative measurements at any hourly interval and no differences in levels comparing patients treated with or without sequential compression devices. CONCLUSIONS: No significant change in systemic fibrinolytic activity occurs during outpatient plastic surgery under total intravenous anesthesia. Sequential compression devices do not affect tissue plasminogen activator or plasminogen activator inhibitor-1 levels, suggesting no fibrinolytic benefit. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, I.

Aspirin-triggered proresolving mediators stimulate resolution in cancer.

Inflammation in the tumor microenvironment is a strong promoter of tumor growth. Substantial epidemiologic evidence suggests that aspirin, which suppresses inflammation, reduces the risk of cancer. The mechanism by which aspirin inhibits cancer has remained unclear, and toxicity has limited its clinical use. Aspirin not only blocks the biosynthesis of prostaglandins, but also stimulates the endogenous production of anti-inflammatory and proresolving mediators termed aspirin-triggered specialized proresolving mediators (AT-SPMs), such as aspirin-triggered resolvins (AT-RvDs) and lipoxins (AT-LXs). Using genetic and pharmacologic manipulation of a proresolving receptor, we demonstrate that AT-RvDs mediate the antitumor activity of aspirin. Moreover, treatment of mice with AT-RvDs (e.g., AT-RvD1 and AT-RvD3) or AT-LXA4 inhibited primary tumor growth by enhancing macrophage phagocytosis of tumor cell debris and counter-regulating macrophage-secreted proinflammatory cytokines, including migration inhibitory factor, plasminogen activator inhibitor-1, and C-C motif chemokine ligand 2/monocyte chemoattractant protein 1. Thus, the pro-resolution activity of AT-resolvins and AT-lipoxins may explain some of aspirin's broad anticancer activity. These AT-SPMs are active at considerably lower concentrations than aspirin, and thus may provide a nontoxic approach to harnessing aspirin's anticancer activity.

The effect of short term treatment with probiotic VSL#3 on various clinical and biochemical parameters in patients with liver cirrhosis.

The evidence is mounting that alterations of innate immunity and gut microbiota contribute to chronic liver disease and its complications. Modulation of intestinal microbiota is an emerging therapeutic strategy in hepatology. Probiotics through modulation of intestinal milieu have the potential to affect the course of liver disease. The data concerning the influence of probiotics on various plasma molecules and compounds involved in the pathogenesis of hyperdynamic circulatory state in liver cirrhosis is still not confluent and require further evaluation. In our study twenty patients with compensated and decompensated liver cirrhosis and ten healthy controls received probiotic VSL#3 daily for 28 days. Plasma levels of interleukin 6 (IL-6), vascular endothelial growth factor (VEGF), plasminogen activator inhibitor (PAI), macrophage inflammatory protein 3/α (MIP-3 α/CCL20), monocyte chemotactic protein-1α (MCP-1/CCL2), human myeloperoxidase (MPO), nitric oxide (NO), prostaglandins, thromboxane (TXB2) and big-endothelin were measured at baseline, day 14 and 28 of probiotic administration. The incidence of hepatic encephalopathy was assessed with critical flicker frequency. Changes in clinical, biochemical and microbiological parameters were evaluated. The stage of liver cirrhosis correlated with an increase in plasma levels of pro-inflammatory cytokines (IL-6) and chemotactic chemokines involved in immune cell trafficking (MIP-3α/CCL20). Probiotic administration in patients with liver cirrhosis led to modulation of plasma levels of several molecules and compounds measured (MIP-3α/CCL20, NO, big-endothelin, TXB2 and MPO). The grade of encephalopathy during the course of probiotic supplementation remained unaffected in both groups of patients. VSL#3 treatment was well tolerated and safe in patients with liver disease. In patients with compensated and decompensated liver cirrhosis, VSL#3 manipulates selected plasma molecules and compounds involved in hyperdynamic circulatory dysfunction. Short term VSL#3 administration affects several clinical and biochemical parameters commonly altered in liver cirrhosis.

Differentiating the Influences of Aging and Adiposity on Brain Weights, Levels of Serum and Brain Cytokines, Gastrointestinal Hormones, and Amyloid Precursor Protein.

Aging and obesity exert important effects on disease. Differentiating these effects is difficult, however, because weight gain often accompanies aging. Here, we used a nested design of aged, calorically restricted, and refed rats to measure changes in brain and blood levels of cytokines and gastrointestinal hormones, brain amyloid precursor protein levels, and brain and body weights. By comparing groups and using path analysis, we found divergent influences of chronological aging versus body weight, our main findings being (i) changes in whole brain weight and serum macrophage colony-stimulating factor levels correlated better with body weight than with chronological aging, (ii) a decrease in brain cytokines and brain plasminogen activator inhibitor levels correlated better with chronological aging than with body weight, (iii) serum erythropoietin levels were influenced by both body weight and aging, (iv) serum plasminogen activator inhibitor, serum cytokines, and brain tumor necrosis factor were not influenced by aging or body weight, and (v) brain amyloid precursor protein more closely related to body weight and serum levels of gastrointestinal hormones than to brain weight, chronological aging, or cytokines. These findings show that although aging and body weight interact, their influences are distinct not only among various cytokines and hormones but also between the central nervous system and the peripheral tissue compartments.

Interactions between the otitis media gene, Fbxo11, and p53 in the mouse embryonic lung.

Otitis media with effusion (OME) is the most common cause of hearing loss in children, and tympanostomy (ear tube insertion) to alleviate the condition remains the commonest surgical intervention in children in the developed world. Chronic and recurrent forms of otitis media (OM) are known to have a very substantial genetic component; however, until recently, little was known of the underlying genes involved. The Jeff mouse mutant carries a mutation in the Fbxo11 gene, a member of the F-box family, and develops deafness due to a chronic proliferative OM. We previously reported that Fbxo11 is involved in the regulation of transforming growth factor beta (TGF-ß) signalling by regulating the levels of phospho-Smad2 in the epithelial cells of palatal shelves, eyelids and airways of the lungs. It has been proposed that FBXO11 regulates the cell's response to TGF-ß through the ubiquitination of CDT2. Additional substrates for FBXO11 have been identified, including p53. Here, we have studied both the genetic and biochemical interactions between FBXO11 and p53 in order to better understand the function of FBXO11 in epithelial development and its potential role in OM. In mice, we show that p53 (also known as Tp53) homozygous mutants and double heterozygous mutants (Jf/+ p53/+) exhibit similar epithelial developmental defects to Fbxo11 homozygotes. FBXO11 and p53 interact in the embryonic lung, and mutation in Fbxo11 prevents the interaction with p53. Both p53 and double mutants show raised levels of pSMAD2, recapitulating that seen in Fbxo11 homozygotes. Overall, our results support the conclusion that FBXO11 regulates the TGF-ß pathway in the embryonic lung via cross-talk with p53.

Plasminogen activation system in oral cancer: Relevance in prognosis and therapy (Review).

Research on carcinogenesis and progress in cancer treatment have reduced mortality of cancer patients. Mortality rates decreased by 1.5% per year from 2001 through 2010 for most types of cancer in men and women. However, oral cancer is still a significant global health problem since incidence and mortality rates are increasing. Oral cavity cancer is ranked the 8th in men and the 14th in women based on data collected between 2006 and 2010 by the National Institute of Health. Furthermore, an increasing incidence of head and neck neoplasms, particularly the tongue cancer among young adults has been reported recently. It is most likely due to increasing human papillomavirus (HPV) infection or the early start of tobacco and alcohol consumption. Treatment of oral cancer patients is mainly surgical and often leads to esthetic and functional deformities, with severe impact on the quality of life. Thus, novel form of treatments and selection of patients with high and low risk of mortality is of high priority for clinical studies. The expression of proteolytic enzymes in tumor and stromal tissues has been shown to have prognostic significance in many human cancers and inhibiting proteolysis can reduce tumor growth in many in vivo and in vitro models. Plasmin, with its activators and inhibitors are of great importance in many human malignances and collectively are called plasminogen activation system (PAS). In this comprehensive review we examine expression, possible prognostic markers and importance for therapy of the PAS members in oral cancer. Literature review suggests that overexpression of urokinase and its receptor are markers of poor outcome, thus, their inhibition can be explored in oral cancer therapy. Role of plasminogen activator inhibitor (PAI-1) is complex and depends on its concentration. Overexpression of PAI-1 favors angiogenesis, metastasis and poor prognosis, although when applied in very high concentrations it inhibits angiogenesis and tumor growth, the phenomenon is described as the PAI-1 paradox.

Prevention of experimental postoperative peritoneal adhesions through the intraperitoneal administration of tanshinone IIA.

Postoperative adhesions develop after nearly every abdominal surgery. The formation of adhesions is associated with the inflammatory response, fibrinolytic system, and extracellular matrix deposition in response to injury. Tanshinone IIA is one of the major extracts obtained from Salvia miltiorrhiza, which has anti-inflammatory effects on many diseases. Postoperative adhesions were induced by injuring the parietal peritoneum and cecum in Wistar rats, followed by the administration of various dosages of tanshinone IIA. The adhesion scores for each group were collected seven days after the initial laparotomy. The activity of the tissue-type plasminogen activator in the peritoneal lavage fluid was measured. The messenger ribonucleic acid expression levels of the tissue-type plasminogen activator, plasminogen activator inhibitor-1, and cyclooxygenase-2 in the ischaemic tissues were measured by quantitative real-time polymerase chain reaction. The intraperitoneal administration of tanshinone IIA is effective for the prevention of the formation of postoperative adhesions in rats. Tanshinone IIA increased fibrinolytic activity in the peritoneal lavage fluid and tissue-type plasminogen activator messenger ribonucleic acid expression in ischaemic peritoneal tissues but decreased the plasminogen activator inhibitor and cyclooxygenase-2 messenger ribonucleic acid expression significantly. These results revealed that tanshinone IIA was a potent postoperative adhesion preventer by enhancing fibrinolytic activity and decreasing cyclooxygenase-2 activity.

Hypercoagulability panel testing predicts thrombosis in neonates undergoing cardiac surgery.

Thrombosis contributes to morbidity and mortality in neonates following cardiac surgery. Alterations in hemostatic factors following cardiac surgery have been described, but there is no data correlating these changes with risk of thrombosis in neonates. The aim of this study is to predict thrombosis in neonates undergoing cardiac surgery by assessment of a panel of hypercoagulability markers. Neonates undergoing cardiac surgery were enrolled preoperatively and prospectively followed. Preoperative hypercoagulability panel testing included thrombin generation assay (TGA), immunoassays for antithrombin III, protein C, protein S, factor VIII, thrombin-activatable fibrinolytic inhibitor (TAFI), plasminogen activator inhibitor-1 (PAI-1), and cardiolipin antibody. Postoperative thrombosis was defined by clinical events (shunt thrombosis, limb ischemia, and stroke) or imaging (intravascular or intracardiac thrombus). Risk factors for thrombosis were assessed. One hundred neonates were enrolled in the study over a two-year period. The incidence of postoperative in-hospital thrombosis was 20%. The only significant clinical risk factor associated with thrombosis was the single ventricle physiology. Hypercoagulability factors associated with increased risk of thrombosis by univariate analysis were elevated PAI-1, TAFI, and TGA, and presence of anticardiolipin antibodies. Multivariable logistic regression analysis demonstrated that elevated PAI-1 (P = 0.015), TAFI (P = 0.028), and TGA (P = 0.007) were independent predictors of thrombosis. Hypercoagulability panel testing may help identify neonates at high risk for thrombosis following cardiac surgery. Future studies are warranted to determine if high risk patients benefit from targeted anticoagulation therapies.

[Clinical prospects of tumor-associated proteases and their tissue inhibitors investigation in oncologic patient].

Review of authors' results and the most representative literature data on the role of tumor-associated proteolitic systems involved in invasion, metastasizing and angiogenic processes in diagnostics and prognosis in various oncologic diseases is presented in this paper. The main attention is paid to the key matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) as well as to the plasminogen activation system components (uPA, PAI-1) study in tumor tissues and peripheral blood. Personal results demonstrated an increase of most MMPs, uPA and PAl-I1 expression in the tumors of 70-90% patients with various neoplasms as compared to histologically unchanged adjacent tissues. MMP- 7 was shown to be a promising serologic marker of ovarian and colorectal cancer (CRC): its sensitivity at 70% specificity level comprised about 70% in both diseases. The greatest clinical interest should be paid to the implication of tumor-associated proteases as prognostic factors. Thus, results of 5-years monitoring have demonstrated that high preoperative serum MMP-7 and TIMP- levels were independent unfavorable prognosticfactors for CRC and univariate analysis revealed unfavorable prognostic role of high tumor MMP- 7 in patients with disseminated process. Tumor PAI-1 level was shown to be a valuable prognosticfactorfor stage III CRC. In the final part of the review possibilities and prospects of tumor-associated proteases usage as targets for specific molecular directed therapy are discussed.

The urokinase plasminogen activator system in breast cancer invasion and metastasis.

The urokinase plasminogen activator system, which is a serine protease family include urokinase-type plasminogen activator (uPA), the uPA receptor and plasminogen activator inhibitors (PAIs). uPA catalyzes the transformation of plasminogen to its active form plasmin, which is able to degrade the extracellular matrix (ECM) and basement membranes, directly or indirectly through activating pro-matrix metalloproteinases (pro-MMPs), promoting cancer cell metastasis and invasion. Both uPA and PAI-1 are poor prognosis markers in primary breast cancer. Evidence has been presented that the uPA system facilitates breast cancer metastasis by several different mechanisms, such as the Ras-ERK pathway and p38 MAPK pathway. This review focuses on uPA system, summarizes their biological effects, highlights the molecular mechanism and pathway, and discusses the role of uPA system in the prevention and treatment of human breast cancers.

A potency of plasminogen activation system in long-term prognosis of endometrial cancer: a pilot study.

OBJECTIVE: Plasminogen activators released from cancer cells lead to degradation of basement membrane proteins and extracellular matrix, and facilitate cancer cell invasion into surrounding tissues and the blood stream. The aim of this study was to evaluate a complex tissue immunohistochemical expression of the plasminogen activation system--urokinase-type plasminogen activator (uPA) and its receptor (uPAR), tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor (PAI)-1--in endometrial cancer, and to correlate obtained results with disease progression and course. STUDY DESIGN: The study group was composed of 100 patients classified in three sub-groups according to the FIGO 2010 tumour stratification (G1=70, G2=19, G3=11). Expression of uPA, tPA, uPAR and PAI-1 was examined by means of immunohistochemical staining. RESULTS: Immunohistochemical expressions of all the studied markers did not differ between G1 and G2 patients. However, G3 subjects were found to have a significantly lower expression of uPA, PAI-1 and tPA. In addition, the patients who survived were found to be PAI-1 negative, while study participants with an unfavourable disease course were PAI-1 positive. CONCLUSIONS: A significantly higher immunohistochemical expression of PAI-1 was found to correlate with shorter relapse-free and overall survival in patients classified as stages IB and II of endometrial cancer.

Evidence for acute vascular toxicity of cisplatin-based chemotherapy in patients with germ cell tumour.

BACKGROUND: Acute early vascular toxicity of chemotherapy for germ cell tumour (GCT) is poorly understood. To explore the pathogenesis of this complication we evaluated laboratory parameters associated with vascular disease. PATIENTS AND METHODS: In 33 GCT patients the following parameters were investigated with routine laboratory methods before and after chemotherapy: von Willebrand factor antigen (vWF:AG), collagen binding capacity (vWF:CB), lipoprotein (a), homocysteine, plasminogen activator inhibitor I, total cholesterol, high density lipoprotein, low density lipoprotein, troponine I. Statistical evaluation involved descriptive analysis and the Wilcoxon signed rank test. RESULTS: Levels of vWF:AG and vWF:CB increased significantly upon therapy (p=0.002). All other parameters remained unchanged. Upon late measurement, vWF:AG and vWF:CB were normalised. CONCLUSION: As von Willebrand factor is released from endothelial cells upon damage, we postulate that early vascular toxicity of chemotherapy is caused by direct damage of the vascular endothelium. Long-term vascular complications of chemotherapy appear to be different, pathogenetically.

Pathogenesis of postoperative adhesion formation.

BACKGROUND: Current views on the pathogenesis of adhesion formation are based on the 'classical concept of adhesion formation', namely that a reduction in peritoneal fibrinolytic activity following peritoneal trauma is of key importance in adhesion development. METHODS: A non-systematic literature search (1960-2010) was performed in PubMed to identify all original articles on the pathogenesis of adhesion formation. Information was sought on the role of the fibrinolytic, coagulatory and inflammatory systems in the disease process. RESULTS: One unifying concept emerged when assessing 50 years of studies in animals and humans on the pathogenesis of adhesion formation. Peritoneal damage inflicted by surgical trauma or other insults evokes an inflammatory response, thereby promoting procoagulatory and antifibrinolytic reactions, and a subsequent significant increase in fibrin formation. Importantly, peritoneal inflammatory status seems a crucial factor in determining the duration and extent of the imbalance between fibrin formation and fibrin dissolution, and therefore in the persistence of fibrin deposits, determining whether or not adhesions develop. CONCLUSION: Suppression of inflammation, manipulation of coagulation as well as direct augmentation of fibrinolytic activity may be promising antiadhesion treatment strategies.

Inhibitory effects of Physalis angulata on tumor metastasis and angiogenesis.

UNLABELLED: ETHNOPHARMACOLOGICAL RELAVENCE: Physalis angulata is well-known in traditional Chinese medicine as a ingredient for various herbal formulation; also, it has been shown to exhibit anti-cancer and anti-inflammatory effects. In this study, the ability of P. angulata to inhibit tumor metastasis and angiogenesis was investigated. MATERIALS AND METHODS: Anti-proliferative activity of ethyl acetate extracts of P. angulata (PA extracts), was determined against human oral squamous carcinoma (HSC-3) and human umbilical vein endothelial cells (HUVECs) by trypan blue exclusion method. Wound-healing migration, trans-well invasion, Western blotting and chick chorioallantoic membrane assay were carried out to determine the anti-metastatic and anti-angiogenic effects of PA extracts in vitro and in vivo. RESULTS: We demonstrated that at sub-cytotoxic concentrations of PA extracts (5-15 µg/mL) markedly inhibited the migration and invasion of highly metastatic HSC-3 cells as shown by wound-healing repair assay and trans-well assay. Gelatin zymography assay showed that PA extracts suppressed the activity of matrix metalloproteinase (MMP)-9 and -2, and urokinase plasminogen activator (u-PA) in HSC-3 cells. In addition, Western blot analysis confirmed that PA extracts significantly decreased MMP-2 and u-PA protein expression in HSC-3 cells. Notably, PA extracts significantly augmented the expression of their endogenous inhibitors, including tissue inhibitors of MMP (TIMP-1 and -2), and plasminogen activator inhibitors (PAI-1 and -2). Further investigations revealed that non-cytotoxic concentration of PA extracts (5-15 µg/mL) inhibited vascular endothelial growth factor (VEGF)-induced proliferation, and migration/invasion of HUVECs in vitro. PA extracts also suppressed the activity of MMP-9, but not MMP-2, in HUVECs. Further, we observed, PA extracts strongly suppressed neovessel formation in the chorioallantoic membrane of chick embryos in vivo. CONCLUSIONS: These results strongly support an anti-metastatic and anti-angiogenic activity of P. angulata that may contribute to the development of better chemopreventive agent for cancer and inflammation.

HMG-CoA reductase inhibitor lovastatin causes reversible cytoskeleton perturbation by RhoA signalling suppression in peritoneal cell line Met5A.

Increasing evidence indicates that statins increase peritoneal fibrinolysis through RhoA-linked pathway and may play a role in the prevention of postoperative adhesion. This study investigated whether lovastatin perturbs cytoskeletons and cell morphology by RhoA suppression in peritoneal Met5A cells. Subcellular distributions of RhoA protein and actin were assessed by immunocytochemical staining. Exposure to lovastatin caused actin filament reorganisation, decrease in the active (membrane-bound) form of RhoA and subsequently cellular shrinkage in Met5A cells. These lovastatin-induced changes were significantly overcome by the addition of geranylgeranyl pyrophosphate (downstream intermediate of HMG-CoA pathway). A RhoA protein inhibitor C3 transferase mimicked the effects of lovastatin on the Met5A cells. The effects of lovastatin on cytoskeleton alterations were correlated well with inhibition of the membrane localisation of RhoA. These results suggest that lovastatin induced reversible cytoskeleton reorganisation and cellular retraction through the reduction of RhoA geranylgeranylation, which in turn suppressed RhoA signalling-associated cellular events.

Paclitaxel potentiates inflammatory cytokine-induced prothrombotic molecules in endothelial cells.

To overcome the limitations of balloon expandible metal stent-induced neointimal smooth muscle cell proliferation, drug-coated stent devices have been developed. Drug eluting stents release high concentrations of antiproliferative agents, such as paclitaxel, to reduce neointimal hyperplasia. The proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), is known to cause severe endothelial dysfunction and accelerate atherosclerotic lesion progression. The interaction of TNF-alpha and paclitaxel on the release of prothrombotic molecules was examined in endothelial cells. Treatment of endothelial cells with paclitaxel had no direct effect on tissue factor (TF) expression, but TNF-alpha increased TF. Cotreatment of paclitaxel with TNF-alpha markedly augmented the release of TF. TNF-alpha induced release of plasminogen activator inhibitor but no synergism occurred with paclitaxel. Treatment of endothelial cells with paclitaxel and TNF-alpha reduced expression of thrombomodulin and protein C receptor. Tissue factor pathway inhibitor expression was reduced by prolonged treatment with either paclitaxel or TNF-alpha. The adhesion molecule, CD62 E, was induced by TNF-alpha; however, CD31, CD62 P, and CD106 were not affected by paclitaxel and TNF-alpha. Apoptosis was not observed with cotreatment of endothelial cells with paclitaxel and TNF-alpha. CD59-positive microparticles were released in response to TNF-alpha, but the release was not augmented by paclitaxel. Paclitaxel and TNF-alpha increased the nitrotyrosination of proteins. These findings indicate that paclitaxel enhances TNF-alpha-induced release of TF, and downregulated thrombomodulin, increased protein nitration, which may subsequently favor prothrombotic intimal surface.

Secretion of fibrinolytic enzymes facilitates human mesenchymal stem cell invasion into fibrin clots.

Adult human mesenchymal stem cells (hMSC) are involved in wound healing and regeneration of mesodermal tissue, but the underlying homing mechanisms are not well understood. Fibrin clot formation is associated with most wound healing processes and potentially guides the recruitment of hMSC. The objective of this study is the investigation of a fibrinolytic capacity, which is required for hMSC to migrate into a wounded tissue and thus to contribute to tissue regeneration. Using RT-PCR, semiquantitative real-time PCR and ELISA, we detected key components of the fibrinolytic cascade, including the urokinase plasminogen activator (uPA) and its receptor (uPAR), the tissue plasminogen activator (tPA) and the plasminogen activator inhibitor (PAI), suggesting a strong fibrinolytic activity of hMSC. To test this activity in a functional assay, we cultured fibrin-embedded hMSC in vitro for 7 days. The cells efficiently dissolved the surrounding fibrin mesh into the fibrin degradation products, the fibrinopeptides. The fibrinolytic activity of hMSC and human dermal fibroblasts, known to be critically involved in skin wound extracellular matrix remodeling, was similar. Our results suggest that a high intrinsic fibrinolytic capacity of hMSC mediates the invasion into a fibrin clot of a wounded tissue.