Effect of Antioxidants on Endothelial Cell Reactive Oxygen Species (ROD Generation and Adhesion of Leukocytes to Endothelial Cells

Objective To investigatewhether antioxidants inhibit adhesion of leukocytes to endothelium and furthermore, whether all antioxidants regulate NF-KB activation through a redox sensitive mechanism. Methods The effect of the antioxidative substances pyrrolidin dithiocarbamat (PDTC), dichloroisocumarin (DCI), chrysin and probucol on the endothelial leukocyte adhesion were examined under near physiological flow conditions. The antioxidative activity of antioxidants was measured in a DCF fluorescence assay with flow cytometry. The activation of NF-kB in endothelial cells was investigated in a gel shift assay. Results PDTC and probucol did not show an inhibitory effect to the formation of intracellular H2O2 in TNFa activated human vascular endothelial cells (HUVEC) . Chrysin showed a moderate effect. DCI showed a strong antioxidative effect. In contrast, PDTC and chrysin inhibited the adhesion of HL 60 cells to TNFa-stimulated HUVEC. DCI and probucol did not have influence on the adhesion within the area of the examined shear stresses. Only PDTC inhibited the TNFa-induced activation of NF-KB in endothelial cells. Conclusion The inhibition of the endothelial leukocyte adhesion by antioxidative substances is not to be explained by its antioxidative characteristics only. The inhibitory effect of PDTC on NF-KB activation was probably not related to its antioxidative properties. Endothelial cell Antioxidants NF-kappa-B

Angiotensin Ⅱ promotes NO production, inhibits apoptosis and enhances adhesion potential of bone marrow-derived endothelial progenitor cells

Endothelial progenitor cells （EPCs） participate in the processes of postnatal neovascularization and re-endothelialization in response to tissue ischemia and endothelial injury. The level of EPCs present has been found to be directly associated with the outcome of cardiovascular diseases, and could be regulated by stimulatory or inhibitory factors. Given the close relationship between angiotensin Ⅱ （AngⅡ） and the cardiovascular＇ system, we investigated the effect of AngⅡ on the activities of bone marrow （BM）-derived EPCs. Cells were isolated from BM of rats by density gradient centrifugation. Administration of AngⅡ significantly promoted nitric oxide （NO） release, inhibited EPC apoptosis and enhanced EPC adhesion potential. All of these AngⅡ-mediated effects on EPCs were attenuated by pretreatment with valsartan or L-NAME. Moreover, both LY294002 and wortmannin abolished the anti-apoptotic effect of AngⅡ. Western blot analyses indicated that endothelial NO synthase （eNOS） protein and phosphorylated Akt increased with the treatment of AngⅡ in EPCs. Thus, AngⅡ improved several activities of EPCs through AngⅡ type 1 receptor （AT1R）, which may represent a possible mechanism linking AnglI and ATIR with angiogenesis. Additionally, AngⅡ-induced NO synthesis through eNOS in EPCs regulates apoptosis and adhesion, and the PI3-kinase/Akt pathway has an essential role in AngⅡ-induced antiapoptosis signaling.

Adhesion of different cell cycle human hepatoma cells to endothelial cells and roles of integrin β_1

AIM: To investigate the adhesive mechanical properties of different cell cycle human hepatoma cells (SMMC-7721) to human umbilical vein endothelial cells (ECV-304), expression of adhesive molecule integrinβ1 in SMMC-7721 cells and its contribution to this adhesive course. METHODS: Adhesive force of SMMC-7721 cells to endothelial cells was measured using micropipette aspiration technique. Synchronous G1 and S phase SMMC-7721 cells were achieved by thymine-2-deoxyriboside and colchicines sequential blockage method and double thymine-2-deoxyriboside blockage method, respectively. Synchronous rates of SMMC-7721 cells and expression of integrinβ1 in SMMC-7721 cells were detected by flow cytometer. RESULTS: The percentage of cell cycle phases of general SMMC-7721 cells was 11.01% in G2/M phases, 53.51% in G0/G1 phase, and 35.48% in S phase. The synchronous rates of G1 and S phase SMMC-7721 cells amounted to 74.09% and 98.29%, respectively. The adhesive force of SMMC-7721 cells to endothelial cells changed with the variations of adhesive time and presented behavior characteristics of adhesion and de-adhesion. S phase SMMC-7721 cells had higher adhesive forces than d phase cells [(307.65±92.10)×10-10N vs(195.42±60.72)×10-10N, P<0.01]. The expressive fluorescent intensity of integrinβ1 in G1 phase SMMC-7721 cells was depressed more significantly than the values of S phase and general SMMC-7721cells. The contribution of adhesive integrinβ1 was about 53% in this adhesive course. CONCLUSION: SMMC-7721 cells can be synchronized preferably in d and S phases with thymine-2-deoxyriboside and colchicines. The adhesive molecule integrinβ1 expresses a high level in SMMC-7721 cells and shows differences in various cell cycles, suggesting integrin β1 plays an important role in adhesion to endothelial cells. The change of adhesive forces in different cell cycle SMMC-7721 cells indicates that S phase cells play predominant roles possibly while they interact with endothelial cells.

Knockdown of CD146 reduces the migration and proliferation of human endothelial cells

Our previous study has demonstrated that CD 146 molecule is a biomarker on vascular endothelium, which is involved in angiogenesis and tumor growth. However the mechanism behind is not clear. Here we have for the first time developed a novel CD146 blockade system using CD146 siRNA to study its function on endothelial cells. Our data showed that CD146 siRNA specifically blocked the expression of CD146 on both mRNA and protein levels, leading to the significant suppression of HUVEC proliferation, adhesion and migration. These results demonstrate that CD146 plays a key role in vascular endothelial cell activity and angiogenesis, and CD146 siRNA can be used as a new inhibitor for anti-angiogenesis therapy.

Expression of platelet endothelial cell adhesion molecule-1 between pancreatic microcirculation and peripheral circulation in rats with acute edematous pancreatitis

OBJECTIVE: To study the ehanges of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in peripheral circulation anti pancreatic microcirculation in rats with acute edematous pancreatitis (AEP). METHODS: The model of AEP was established with 50 Wistar rats, and the changes of PECAM-1 expression on PMNs from the splenic vein and inferior vena cava were determined by flow cytometry. RESULTS: PECAM-I expression on PMNs showed no significant difference between pancreatic microcirculation and peripheral circulation at AEP2h and AEP4h time points. From the AEP4h to the AEP8h time point, PECAM-1 expression in peripheral circulation was up-regulated, but PECAM-1 expression in pancreatic microcirculation was down-regulated. PECAM-1 expression had a significant difference between pancreatic microcirculation and peripheral circulation at the AEP8h time point (P<0.05). CONCLUSION: PECAM-1 expression on PMNs is in a converse way between pancreatic microcirculation and peripheral circulation in AEP.

Effects of Exogenous Sonic Hedgehog Peptide on Proliferation, Adhesion, Migration of Endothelial Progenitor Cells from Peripheral Blood

Summary： In order to study the effects of exogenous sonic hedgehog （shh） peptide on proliferation, adhesion, migration of endothelial progenitor cells （EPCs） from rat peripheral blood, the mononuclear cells were collected from rat peripheral blood by Ficoll density gradient centrifugation. EPCs were iso- lated with adherence screening method and cultured in M199 culture medium with the supplement of VEGF and bFGF. The immunohistochemical staining was used to identify cell markers such as CD133 and VEGFR-2. EPCs were stimulated with exogenous shh peptide of different final concentrations （0.01, 0.1, 1, 10 μg/mL）. The proliferation, adhesion and migration of EPCs were detected by MTT chromom- etry, adhesion test and transwell system, respectively. The results of this study showed that, after 7 days of culture, cells formed clusters, assuming typical cobbles-tone pattern under microscope. After 2 weeks of culture, cells were arranged in cord-like fashion and sometimes grew like ＂micro-vessels＂. Immuno- histochemical staining showed that the cultured cells were positive for both CD133 and VEGFR-2. The proliferation, adhesion and migration of EPCs could be promoted by endogenous shh peptide at concen- trations from 0.1 μg/mL to 10 μg/mL in a concentration-dependent manner. The findings indicate that exogenous shh peptide can enhance EPCs proliferation, adhesion, and migration, which may have a po- tential value for clinical application.

Adhesion behavior of endothelial progenitor cells to endothelial cells in simple shear flow

The adhesion of endothelial progenitor cells（EPCs） on endothelial cells（ECs） is one of the critical physiological processes for the regenesis of vascular vessels and the prevention of serious cardiovascular diseases.Here,the rolling and adhesion behavior of EPCs on ECs was studied numerically.A two-dimensional numerical model was developed based on the immersed boundary method for simulating the rolling and adhesion of cells in a channel flow.The binding force arising from the catch bond of a receptor and ligand pair was modeled with stochastic Monte Carlo method and Hookean spring model.The effect of tumor necrosis factor alpha（TNF-α） on the expression of the number of adhesion molecules in ECs was analyzed experimentally.A flow chamber system with CCD camera was set up to observe the top view of the rolling of EPCs on the substrate cultivated with ECs.Numerical results prove that the adhesion of EPC on ECs is closely related to membrane stiff-ness of the cell and shear rate of the flow.It also suggests that the adhesion force between EPC and EC by P-selectin glycoprotein ligand-1 only is not strong enough to bond the cell onto vessel walls unless contributions of other catch bond are considered.Experimental results demonstrate that TNF-α enhanced the expressions of VCAM,ICAM,P-selectin and E-selectin in ECs,which supports the numerical results that the rolling velocity of EPC on TNF-α treated EC substrate decreases obviously compared with its velocity on the untreated one.It is found that because the adhesion is affected by both the rolling velocity and the deformability of the cell,an optimal stiffness of EPC may exist at a given shear rate of flow for achieving maximum adhesion rates.

The roles of focal adhesion and cytoskeleton systems in fluid shearstress-induced endothelial cell response

Focal adhesions are polyproteins linked to extracellular matrix and cytoskeleton,which play an important role in the process of transforming force signals into intracellular chemical signals and subsequently triggering related physiological or pathological reactions.The cytoskeleton is a network of protein fibers in the cytoplasm,which is composed of microfilaments,microtubules,intermediate filaments,and cross-linked proteins.It is a very important structure for cells to maintain their basic morphology.This review summarizes the process of fluid shear stress transduction mediated by focal adhesion and the key role of the cytoskeleton in this process,which focuses on the focal adhesion and cytoskeleton systems.The important proteins involved in signal transduction in focal adhesion are introduced emphatically.The relationship between focal adhesion and mechanical transduction pathways are discussed.In this review,we discuss the relationship between fluid shear stress and associated diseases such as atherosclerosis,as well as its role in clinical research and drug development.

Effect of serum concentration on adhesion of monocytic THP-1 cells onto cultured EC monolayer and EC-SMC co-culture

Background:The adhesion of monocytes to the endothelium following accumulation of low-density lipoprotein (LDL) in subendothelial spaces is an important step in the development of intimal hyperplasia in arterially implanted vein grafts and atherosclerosis in both animals and humans. However, it is not well known how serum factors affect the adhesion of monocytes. Methods: We have studied the effect of fetal calf serum (FCS), which we considered a source of LDL, on the adhesion of monocytes to endothelial cells (ECs) by using human monocytic THP-1 cells and both a monolayer of cultured bovine aortic endothelial cells (EC monoculture) and a co-culture with bovine aortic smooth muscle cells (EC-SMC co-culture). Results: It was found that the addition of FCS to the medium greatly affected the adhesion of THP-1 cells, and the higher the concentration of FCS in the medium, the greater the adhesion of THP-1 cells to endothelial cells. Adhesion of THP-1 cells to an EC-SMC co-culture was approximately twofold greater than that to an EC monoculture, and after adhering to endothelial cells, many THP-1 cells trans-migrated into the layer of smooth muscle cells. Conclusion: The results suggest that the elevation of the LDL (cholesterol) level in blood provides a favorable condition for the development of intimal hyperplasia and atherosclerosis by promoting the adhesion of monocytes to the endothelium and their subsequent migration into subendothelial spaces.

Effects of Sirt1 on proliferation,migration,and apoptosis of endothelial progenitor cells in peripheral blood of SD rats with chronic obstructive pulmonary disease

Objective:To explore the effect of Sirt1 on the function of endothelial progenitor cells(EPCs)in rats with chronic obstructive pulmonary disease(COPD).Methods:A rat COPD model was established via smoking and endotoxin administration for three months.The peripheral circulating EPCs were isolated by gradient centrifugation,and their functions,cell cycle distribution,apoptosis,and Sirt1 expression were examined.The function changes of EPCs in the presence or absence of Sirt1 agonist and inhibitor were estimated;meanwhile,the expressions of Sirt1,FOXO3a,NF-κB,and p53 were also evaluated.Results:The proliferation,adhesion,and migration of EPCs decreased while the apoptosis rate was increased in the COPD rats.The expression of Sirt1 protein in EPCs of the COPD group was significantly lower than that in the control group(P<0.01).The overexpression of the Sirt1 gene using a gene transfection technique or Sirt1 agonists(SRT1720)improved the proliferation,migration,and adhesion,and decreased the apoptosis of EPC.However,Sirt1 inhibitor(EX527)decreased EPC functions in the COPD group.The effect of Sirt1 expression on EPC function may be related to reduction of FOXO3a and increase of NF-κB and p53 activity.Conclusions:Increased expression of Sirt1 can improve the proliferation and migration of EPCs and reduce their apoptosis in COPD rats.This change may be related to FOXO3a,NF-κB,and p53 signaling pathways.

Integrin binding peptides facilitate growth and interconnected vascular-like network formation of rat primary cortical vascular endothelial cells in vitro

Neovascularization and angiogenesis in the brain are important physiological processes for normal brain development and repair/regeneration following insults. Integrins are cell surface adhesion receptors mediating important function of cells such as survival, growth and development during tissue organization, differentiation and organogenesis. In this study, we used an integrin-binding array platform to identify the important types of integrins and their binding peptides that facilitate adhesion, growth, development, and vascular-like network formation of rat primary brain microvascular endothelial cells. Brain microvascular endothelial cells were isolated from rat brain on post-natal day 7. Cells were cultured in a custom-designed integrin array system containing short synthetic peptides binding to 16 types of integrins commonly expressed on cells in vertebrates. After 7 days of culture, the brain microvascular endothelial cells were processed for immunostaining with markers for endothelial cells including von Willibrand factor and platelet endothelial cell adhesion molecule. 5-Bromo-2′-dexoyuridine was added to the culture at 48 hours prior to fixation to assess cell proliferation. Among 16 integrins tested, we found that α5β1, αvβ5 and αvβ8 greatly promoted proliferation of endothelial cells in culture. To investigate the effect of integrin-binding peptides in promoting neovascularization and angiogenesis, the binding peptides to the above three types of integrins were immobilized to our custom-designed hydrogel in three-dimensional(3 D) culture of brain microvascular endothelial cells with the addition of vascular endothelial growth factor. Following a 7-day 3 D culture, the culture was fixed and processed for double labeling of phalloidin with von Willibrand factor or platelet endothelial cell adhesion molecule and assessed under confocal microscopy. In the 3 D culture in hydrogels conjugated with the integrin-binding peptide, brain microvascular endothelial cells formed interconnected vascular-like network with clearly discernable lumens, which is reminiscent of brain microvascular network in vivo. With the novel integrin-binding array system, we identified the specific types of integrins on brain microvascular endothelial cells that mediate cell adhesion and growth followed by functionalizing a 3 D hydrogel culture system using the binding peptides that specifically bind to the identified integrins, leading to robust growth and lumenized microvascular-like network formation of brain microvascular endothelial cells in 3 D culture. This technology can be used for in vitro and in vivo vascularization of transplants or brain lesions to promote brain tissue regeneration following neurological insults.

Hypoxia Inhibits Proliferation of Human Dermal Lymphatic Endothelial Cells via Downregulation of Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 Expression

Objective:Lymphatic endothelial cell(LEC)proliferation is essential for lymphangiogenesis.Hypoxia induces lymphangiogenesis,but it directly inhibits LEC proliferation and the underlying mechanisms have not been fully understood.The aim of this study was to investigate the role of carcinoembryonic antigen-related cell adhesion molecule 1(CEACAM1)in hypoxia-repressed LEC proliferation.Methods:Human dermal lymphatic endothelial cells(HDLECs)were cultured under normoxic or hypoxic conditions,and cell proliferation was determined using MTT or CCK-8 assays.CEACAM1 expression was silenced by siRNA transfection.Activation of mitogen-activated protein kinases(MAPKs)was examined by Western blotting and blocked by specific inhibitors.Results:Under hypoxia,HDLECs proliferation was suppressed and CEACAM1 expression was downregulated.Silence of CEACAM1 in normoxia inhibited HDLECs proliferation and did not further decrease proliferation in HDLECs in response to hypoxia,suggesting that CEACAM1 may mediate hypoxia-induced inhibition of HDLECs proliferation.In addition,silence of CEACAM1 increased phosphorylation of MAPK molecules:extracellular signal-regulated kinase(ERK),p38 MAPK and Jun N-terminal kinase(JNK)in HDLECs.However,only inhibition of the JNK pathway rescued the reduction of HDLEC proliferation induced by CEACAM1 silence.Conclusion:Our results suggested that hypoxia downregulates CEACAM1 expression by activation of the JNK pathway,leading to inhibition of HDLEC proliferation.These findings may help to understand the mechanisms of LEC-specific response to hypoxia and develop novel therapies for pathological lymphangiogenesis.

The law of anti-VCAM-1 targeted microbubbles adhesion to activated endothelial cells under controlled shear flow

Microbubbles can enhance the detection in noninvasive ultrasound imaging.Recently,targeted microbubbles have been developed to selectively adhere to specific and overexpressed p molecules in endothelial cells in some pathologic conditions.However,the law of

Effects of TCMP-1 on the changes of platelet endothelial cell adhesion molecule-1 expression in acute edematous pancreatitis

BACKGROUND: Traditional Chinese medicine is a potent agent in the management of clinical and experimental acute pancreatitis (AP), but the molecular mechanism of its the- rapeutic action is unclear. Numerous experimental and clinical studies have shown that platelet endothelial cell ad- hesion molecule-1 (PECAM-1) is pivotal to leukocyte re- cruitment, which results in microcirculatory injury during inflammation, but its role in acute pancreatitis is poorly un- derstood. We investigated the effects of a compound of tra- ditional Chinese medicine pancreatitis-1 (TCMP-1) on the changes of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in acute edematous pancreatitis (AEP). METHODS: The model of acute pancreatitis was estab- lished by subcutaneous injection of caerulein, and TCMP-1 treated groups were given TCMP-1 by catheterization from mouth to stomach (20 ml/kg) immediately after first time subcutaneous injection of caerulein. The changes of expres- sion of PECAM-1 on leukocytes from the blood of the splenic vein and inferior vena cava were determined by flow cytometry. RESULTS: In the AEP group, expression of PECAM-1 on PMNs was not significantly different between pancreatic microcirculation and systemic circulation at AEP2h and AEP4h time point. Then from AEP4h time point to AEP8h time point, expression of PECAM-1 was up-regulated in systemic circulation while it was down-regulated in pancre- atic microcirculation and was significantly different be- tween pancreatic microcirculation and systemic circulation at AEP8h time point (P<0.05). In the TCMP-1 treated group, compared with the AEP group, expression of PE-CAM-1 on PMNs decreased in different levels between pan- creatic microcirculation and systemic circulation and was of significant difference at AEP8h time point (P <0.05). CONCLUSION: Inhibition of PECAM-1 expression on PMNs may prevent PMNs from transmigration through the endo- thelium and may be one of the treatment mechanisms of TCMP-1 decoction on AEP.

The relationship between platelet endothelial cell adhesion molecule-1 and paraquat-induced lung injury in rabbits

BACKGROUND:Platelet endothelial cell adhesion molecule-1(PECAM-1),also known as CD31,is mainly distributed in vascular endothelial cells.Studies have shown that PECAM-1 is a very significant indicator of angiogenesis,and has been used as an indicator for vascular endothelial cells.The present study aimed to explore the relationship between the expression of PECAM-1 and the degree of acute lung injury(ALI) and fibrosis in paraquat(PQ) induced lung injury in rabbits.METHODS:Thirty-six adult New Zealand rabbits were randomly divided into three groups(12rabbits in each group) according to PQ dosage:8 mg/kg(group A),16 mg/kg(group B),and 32 mg/kg(group C).After PQ infusion,the rabbits were monitored for 7 days and then euthanized.The lungs were removed for histological evaluation.Masson staining was used to determine the degree of lung fibrosis(LF),and semi-quantitative immune-histochemistry analysis to determine the expression of PECAM-1.Pearson's product-moment correlation analysis was performed to evaluate the relationship between the expression of PECAM-1 and the extent of lung injuries expressed by ALI score and degree of LF.RESULTS:Rabbits in the three groups showed apparent poisoning.The rabbits survived longer in group A than in groups B and C(6.47±0.99 days vs.6.09±1.04 days vs.4.77±2.04 days)(P<0.05).ALI score was lower in group A than in groups B and C(8.33±1.03 vs.9.83±1.17 vs.11.50±1.38)(P<0.05),and there was statistically significant difference between group B and group C(P=0.03).LF was slighter in group A than in groups B and C(31.09%±2.05%vs.34.37%±1.62%vs.36.54%±0.44%)(P<0.05),and there was statistically significant difference between group B and group C(P=0.026).The PEACAM-1 expression was higher in group A than in groups B and C(20.31%±0.70%vs.19.34%±0.68%vs.18.37%±0.46%)(P<0.05),and there was statistically significant difference between group B and group C(P=0.017).Pearson's correlation analysis showed that the expression of PECAM-1 was negatively correlated to both ALI score(Coe=-0.732,P=0.001)and degree of LF(Coe=-0.779,P<0.001).CONCLUSIONS:The PECAM-1 expression significantly decreases in New Zealand rabbits after PQ poisoning,and the decrease is dose-dependent.The PECAM-1 expression is negatively correlated with ALI score and LF,showing a significant role in the development of lung injuries induced by PQ.

Forces of RBC interaction with single endothelial cells in stationary conditions:Measurements with laser tweezers

Red blood cells(RBCs)are able to interact and communicate with endothelial cells(ECs).Under some pathological or even normal conditions,the adhesion of RBCs to the endothelium can be observed.Presently,the mechanisms and many aspects of the interaction between RBCs and ECs are not fully understood.In this work,we considered the interaction of single RBCs with single ECs in vitro aiming to quantitatively determine the force of this interaction using laser tweezers.Measurements were performed under different concentrations of proaggregant macromolecules and in the presence or absence of tumor necrosis factor(TNF-α)activating the ECs.We have shown that the strength of interaction depends on the concentration of fibrinogen or dextran proaggregant macromolecules in the environment.A nonlinear increase in the force of cells interaction(from 0.4 pN to 21 pN)was observed along with an increase in the fibrinogen con-centration(from 3 mg/mL to 9 mg/mL)in blood plasma,as well as with the addition of dextran macromolecules(from 10 mg/mL to 60 mg/mL).Dextran with a higher molecular mass(500 kDa)enhances the adhesion of RBCs to ECs greater compared to the dextran with a lower molecular mass(70 kDa).With the preliminary activation of ECs with TNF-α,the force of interaction increases.Also,the adhesion of echinocytes to EC compared to discocytes is significantly higher.These results may help to better understand the process of interaction between RBCs and ECs.

Differences in platelet endothelial cell adhesion molecule-1 expression between peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis

AIM: To investigate the changes of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis (AEP).METHODS: Fifty Wistar rats were randomly divided into control group (n=10) and AEP group (n=40). A model of AEP was established by subcutaneous injection of cerulein 5.5 and 7.5 μg/kg at 0 and 1 h after the beginning of experiment respectively. PECAM-1 expression on PMNs from splenic vein and inferior vena cava was determined by RT-PCR at mRNA level and determined by flow cytometry at protein level.RESULTS: In experimental rats, an increased PECAM-1mRNA expression was seen from 4 to 8 h of AEP in peripheral circulation (0.77±0.25%, 0.76±0.28%, 0.89±0.30%,1.00±0.21% ), while in pancreatic microcirculation,expression decreased from 2 h and reached the lowest level at 6 h of AEP (0.78±0.29%, 0.75±0.26%, 0.62±0.28%,0.66±0.20%). There were significant differences at 8-h time point of AEP between peripheral circulation and pancreatic microcirculation (1.00±0.21% vs0.66±0.20%, P＜0.05).Meanwhile,the difference at protein level was also found.CONCLUSION: A reverse expression of PECAM-1 on PMNs was found between peripheral circulation and pancreatic microcirculation, suggesting that inhibition of PECAM-1expression may improve the pathological change of AEP.

Study of plasma effects during hypoxia and hemorrhagic shock on polymorphonuclear neutrophil-vascular endothelial cell interactions in vitro

The plasma effects during hypoxia and hemorrhagic shock on the interactions between plymorphonuclear neutrophils (PMNs) and cultured pulmonary artery endothelial cells (PAECs) were studied. The plasma samples were obtained from the goats under the following conditions: (1)Normal control plasma was obtained from the goats at sea level to aserve as the control (CP). (2)Hypoxic plasma was obtained after the goats were exposed to a simulated altitude of 4 000 m for 24 h (HP). (3) Hypotensive hypoxic plasma was obtained after the goats were bled to a mean arterial pressure of 5. 5±0. 3 kpa for 1 h under hypoxic condition (HHP). (4) Retransfused hypoxic plasma was obtained when the hypotensive goats were transfused with the shed blood for 4 h under hypoxic condition (RHP). It was found that HP , HHP and RHP especially RHP exerted profound effects on the activities of PMNs and PAECs in a concentration and time dependent manner after the PMNs and PAECs were incubated in the media containing different concentrations of the 4 kinds of plasma for different durations. Low concentration of RHP (less than 12. 5%) significantly increased the activity of PAECs (P<0. 01 vs CP) but its high concentration (more than 12. 5%) markedly decreased their activity (P<0. 01 vs CP, HP and HHP). HP, HHP and RHP increased the activity of PAECs in the early stage of incubation (1 to 3 h) (P<0. 01 vs CP) but decreased it in the late stage (6 to 12 h) (P<0. 01 vs CP). The activity of PMNs was significantly increased after 1 h incubation with HP, HHP and RHP (PM0. 001) and this effect was also concentrationdependent.The effects of RHP was the most potent, HHP the next and HP the least. The deformability of PMNs was significantly decreased (P <0. 001) after they were incubated in RHP for 3 h. The adhesive force of PMNs and PAECs was also significantly increased after 12 h incubation with RHP. These findings suggest that there are substances in the hypoxic plasma to activate or damage the interactions between PMNs and PAECs and the amounts of the substances are further increased in hypotensive hypoxic plasma and retransfused hypoxic plasma and the 'activation-damage'to PMNs and PAECs and the subsequent interactions between PMNs and PAECs play an important role in the pathological changes of hypoxia and hemorrhagic shock.

Oxidatively Modified Very Low Density Lipoprotein Enhances Monocyte Adhesion to Endothelial Cells

Very low density lipoprotein (VLDL) was incubated with CuCl2(10 μmol/L) at room temperature for 24 hours.The thiobarbituric acid reactive substance (TBARS) was much higher and the electrophoretic mobility was much faster in VLDL after incubation with CuCl2 than that in VLDL without incubation with CuCl2.It demonstrated that VLDL was oxidatively modified by Cu2+. Endothelial cells were pretreated with normal VLDL ( N-VLDL ) and oxidatively modified VLDL (OVLDL) and then the adhesion of monocyte to endothelial cells was assayed. We observed that O-VLDL at all the concentrations used enhanced monocyte adhesion to endothelial cells significantly. The results suggest that oxidative modification of VLDL may play a role in the early stage of atherogenesis by increasing monocyte adhesion to endothelial cells.

Molecular basis of the adhesive process of polymorphonuclear neutrophils to vascular endothelial cells under endotoxin condition

The monocellular adhesive ability of polymorphonuclear neutrophils (PMN)to vascular endothelial cells (VEC) was observed with micromanipulation technique when the cells were treated with endotoxin, Anti-CD18 monoclonal antibodies (McAb),anti-endothelial-leucocytic adhesion molecule-l (ELAM-l)McAb and anti-intercellular adhesion molecule-1 (ICAM-1) McAb and the effects of these 3 adhesion molecules on the development of adhesion force between PMNs and VECs were investigated. It was found that CD18 McAb decreased obviously the adhesive ability of PMNs in the whole course of adhesion increasing and the McAbs of ELAM-1 and ICAMI-1 inhibited most of adhesive force of VECs in the 4th and 12th hour of the course respectively.These findings suggest that the main molecular basis of rapid increase of adhesive ability of PMNs is CD18 expression and that of delayed increase of adhesive ability of VECs is ELAM-1 and ICAM-1 expression.