Inhibition of the thrombogenic and inflammatory properties of antiphospholipid antibodies by fluvastatin in an in vivo animal model

OBJECTIVE: Antiphospholipid antibodies (aPL) have thrombogenic properties in vivo, through their interactions with soluble coagulation factors and their ability to modulate the functions of cells involved in coagulation homeostasis. These antibodies have also been shown to enhance the adhesion of leukocytes to endothelial cells (ECs) in vivo. New lipophilic statins such as fluvastatin have antiinflammatory and antithrombogenic effects. This study uses an in vivo mouse model to investigate whether fluvastatin has an effect on decreasing both the adhesion of leukocytes to ECs and the thrombus formation induced by aPL. METHODS: Two groups of CD-1 male mice, each comprising approximately 18 mice, were fed either normal saline solution or 15 mg/kg fluvastatin for 15 days. Each of the 2 groups was further subdivided to receive either purified IgG from patients with the antiphospholipid syndrome (IgG-APS) or normal IgG from healthy subjects. Analysis of thrombus dynamics was performed in treated and control mice, using a standardized thrombogenic injury procedure, and the area (size) of the thrombus was measured. Adhesion of leukocytes to ECs was analyzed with a microcirculation model of exposed cremaster muscle. Baseline and posttreatment soluble intercellular adhesion molecule 1 (sICAM-1) levels were determined by enzyme-linked immunosorbent assay. RESULTS: IgG-APS mice treated with fluvastatin showed significantly smaller thrombi, a reduced number of adherent leukocytes, and decreased levels of sICAM-1 compared with IgG-APS animals treated with placebo. CONCLUSION: These findings indicate that fluvastatin significantly diminishes aPL-mediated thrombosis and EC activation in vivo. These results may have important implications for the design of new treatment strategies aimed at preventing recurrent thrombosis in patients with APS.     

Probing antiphospholipid-mediated thrombosis: the interplay between anticardiolipin antibodies and endothelial cells

The association of antiphospholipid (aPL) antibodies with thrombosis in patients with antiphospholipid syndrome (APS) is well documented in humans and in animal studies. However, the mechanisms by which aPL antibodies induce thrombosis are the subject of much current study. It has been suggested that aPL may activate endothelial cells (ECs), thus creating a hypercoagulable state that precedes and contributes to thrombosis in patients with APS. Several studies have shown that aPL upregulate ECs' adhesion molecules (CAMs): intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin (E-sel) or induce tissue factor (TF) in monocytes in vitro. Similarly, the incubation of EC with antibodies reacting with beta2glycoprotein I (beta2GPI) has been shown to induce EC activation with concomitant upregulation of CAMs, IL-6 production and alteration of prostaglandin metabolism. Our group has shown that aPL-mediated upregulation of adhesion molecules on ECs correlates with an increased adhesion of leukocytes to endothelium in the microcirculation of mouse cremaster muscle, a n indication of EC activation in vivo, andwith enhanced thrombosis in vivo. In another series of studies, investigators have shown that upregulation of expression of adhesion molecules by some murine monoclonal anti-beta2glycoprotein I (anti-beta2GPI) antibodies correlated with fetal resorption in mice in vivo. More recently, one study showed that the anti-hypercholesterolaemic drug fluvastatin inhibited the aPL-mediated enhanced adhesion of monocytes to ECs in vitro. Data from our laboratories indicate that fluvastatin also reverses thrombus formation and activation of EC induced by aPL in an in vivo mouse model. As additional support for the hypothesis that aPL antibodies activate ECs and may create an hypercoagulable state in APS patients, two recent studies indicated that levels of soluble ICAM-1 and VCAM-1 were significantly increased in the plasma of patients with APS and recurrent thrombosis. Furthermore, studies utilizing knockout mice and specific monoclonal anti-VCAM-1 antibodies have demonstrated that expression of ICAM-1, P-selectin, E-selectin and VCAM-1 are important in in vivo aPL-mediated thrombosis and EC activation in mice. Recent data suggests that aPL antibodies also induce expression of TF not only in monocytes but in ECs. Hence, the interference of aPL with the TF mechanism may be another important mechanism by which these antibodies create a hypercoagulable state and prone patients to thrombosis. Specifically, how aPL alters EC activation state and the molecular and intracellular mechanisms involved have not yet been defined. APL may interact with specific cell surface receptors (proteins and/or lipids) induce signals that have consequences downstream, and that ultimately will result in upregulation of cell surface proteins (i.e., CAMs and TF) and subsequently induce EC activation. In that regard, our group recently showed that aPL-mediated upregulation of adhesion molecules in ECs is preceded by activation of the nuclear factor kappa B (NFkappaB). Other intracellular mechanisms triggered by aPL are not completely understood and are the subject of current investigation. In conclusion, studies suggest that activation of ECs by aPL is an important mechanism that may precede thrombus formation in patients with APS. Hence, the interplay between aPL antibodies and ECs is important inthe pathogenesis of thrombosis in APS.     

Vascular cell adhesion molecule-1 is involved in mediating hypoxia- induced sickle red blood cell adherence to endothelium: potential role in sickle cell disease

We investigated the effects of hypoxia on red blood cell (RBC)- endothelial cell (EC) adherence and the potential mechanism(s) involved in mediating this effect. We report that hypoxia significantly increased sickle RBC adherence to aortic EC when compared with the normoxia controls. However, hypoxia had no effect on the adherence of normal RBCs. In additional studies, we found that the least dense sickle RBCs containing CD36+ and VLA-4+ reticulocytes were involved in hypoxia-induced adherence. We next evaluated the effects of hypoxia on the expression of EC surface receptors involved in RBC adherence to macrovascular ECs, including vascular cell adhesion molecule-1 (VCAM- 1), intracellular adhesion molecule-1 (ICAM-1), and the vitronectin receptor (VnR). Hypoxia upregulated the expression of both VCAM-1 and ICAM-1, whereas no effect on VnR was noted. Potential involvement of VCAM-1 and ICAM-1 in mediating hypoxia-induced sickle RBC-EC adhesion was next investigated using monoclonal antibodies against these receptors. Whereas anti-VCAM-1 had no effect on basal adherence, it inhibited hypoxia-induced sickle RBC adherence in a concentration- dependent manner, with 50% to 75% inhibition noted at 10 to 60 micrograms/mL antibody (n = 6, P < .05 to P < .01). Anti-ICAM-1 (10 to 60 micrograms/mL, n = 8) had no effect on either basal or hypoxia- induced adherence. As noted in the bovine aortic ECs, hypoxia stimulated the adherence of sickle RBCs to human retinal capillary ECs, and this response appeared to be mediated via mechanisms similar to those observed with macro-endothelium, ie, via the adhesive receptor combination VCAM-1-VLA-4. Our studies show that hypoxia enhances sickle RBC adhesion to both macrovascular and human microvascular ECs via the adhesive receptor VCAM-1. Our findings are of interest because hypoxia is an integral part of the pathophysiology of the vaso-occlusive phenomenon in sickle cell anemia.     

Migration inhibitory factor up-regulates vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 via Src, PI3 kinase, and NFkappaB

Cell adhesion molecules are critical in monocyte (MN) recruitment in immune-mediated and hematologic diseases. We investigated the novel role of recombinant human migration inhibitory factor (rhMIF) in up-regulating vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) and their signaling pathways in human MNs. rhMIF-induced expression of VCAM-1 and ICAM-1 was significantly higher compared with nonstimulated MNs. rhMIF induced MN VCAM-1 and ICAM-1 expression in a concentration-dependent manner (P < .05). Antisense oligodeoxynucleotides (ODNs) and inhibitors of Src, PI3K, p38, and NFkappaB significantly reduced rhMIF-induced MN VCAM-1 and ICAM-1 expression (P < .05). However, Erk1/2 and Jak2 were not involved. Silencing RNA directed against MIF, and inhibitors of Src, PI3K, NFkappaB, anti-VCAM-1, and anti-ICAM-1 significantly inhibited rhMIF-induced adhesion of HL-60 cells to human dermal microvascular endothelial cells (HMVECs) or an endothelial cell line, HMEC-1, in cell adhesion assays, suggesting the functional significance of MIF-induced adhesion molecules (P < .05). rhMIF also activated MN phospho-Src, -Akt, and -NFkappaB in a time-dependent manner. rhMIF induced VCAM-1 and ICAM-1 up-regulation in 12 hours via Src, PI3K, and NFkappaB as shown by Western blotting and immunofluorescence. MIF and MIF-dependent signaling pathways may be a potential target for treating diseases characterized by up-regulation of cell adhesion molecules.     

Circulating intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin in patients with type 2 diabetes mellitus

Serum levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin in patients with type 2 diabetes mellitus (n = 64) and control subjects (n = 40) were studied. Serum ICAM-1 concentrations in diabetic patients were significantly higher than those of control subjects (378.2 +/- 70.0 versus 220.4 +/- 31.8 ng/ml, P < 0.01). By multiple regression analysis, hemoglobin A1c was independently associated with serum ICAM-1 concentration in patients with diabetes. The serum VCAM-1 concentration of diabetic patients with macroangiopathy was higher than those of patients without macroangiopathy and of control subjects (806.9 + 276.5 versus 639.0 +/- 146.0 (P < 0.01), and 652.1 +/- 146.9 ng/ml (P < 0.01), respectively). There was no difference in serum E-selectin concentration between diabetic patients with or without macroangiopathy and normal control subjects. These results suggest that adhesion molecules may contribute to the development of atherosclerosis in the diabetic state.     

Serum levels of thrombomodulin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin in the acute phase of Plasmodium vivax malaria

Elevated plasma or serum levels of thrombomodulin (TM), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin have been reported in several diseases. However, plasma or serum levels of TM, ICAM-1, VCAM-1, and E-selectin have not been investigated in the acute phase of Plasmodium vivax malaria. Serum TM, ICAM-1, VCAM-1, E-selectin, and creatinine levels were determined in six Japanese patients in the acute phase of vivax malaria and in seven healthy Japanese controls. Parasitemias of the peripheral blood were < 0.1% in five patients and 0.8% in one patient. The patients' mean +/- SD serum levels of TM, ICAM-1, VCAM-1, and E-selectin were 5.7 +/- 1.3 Fujirebio units/ml, 709 +/- 397 ng/ml, 2,112 +/- 782 ng/ml, and 99 +/- 28 ng/ml, respectively, and all were significantly greater than those in the controls (TM; P < 0.005, ICAM-1; P < 0.025, VCAM-1; P < 0.005, E-selectin; P < 0.025). However, no significant difference was identified between patients and controls for serum creatinine values. The serum levels of TM and VCAM-1 were not related to parasitemia. The elevation of serum TM levels suggests that endothelial cell damage occurs in the acute phase of vivax malaria.     

Patterns of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 expression in rabbit and mouse atherosclerotic lesions and at sites predisposed to lesion formation.

The recruitment of mononuclear leukocytes and formation of intimal macrophage-rich lesions at specific sites of the arterial tree are key events in atherogenesis. Inducible endothelial cell adhesion molecules may participate in this process. In aortas of normal chow-fed wild-type mice and rabbits, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), but not E-selectin, were expressed by endothelial cells in regions predisposed to atherosclerotic lesion formation. En face confocal microscopy of the mouse ascending aorta and proximal arch demonstrated that VCAM-1 expression was increased on the endothelial cell surface in lesion-prone areas. ICAM-1 expression extended into areas protected from lesion formation. Hypercholesterolemia induced atherosclerotic lesion formation in rabbits, LDL receptor and apolipoprotein E knockout mice, and Northern blot analysis demonstrated increased steady-state mRNA levels of VCAM-1 and ICAM-1, but not of E-selectin. Immunohistochemical staining revealed that VCAM-1 and ICAM-1 were expressed predominantly by endothelium in early lesions and by intimal cells in more advanced lesions. In early and advanced lesions, staining was most intense in endothelial cells at and adjacent to lesion borders. ICAM-1 staining extended into the uninvolved aorta. These expression patterns were highly reproducible in both species. The only difference was that VCAM-1 expression in endothelium over the central portions of lesions was found frequently in rabbits and rarely in mice. The expression of VCAM-1 by arterial endothelium in normal animals may represent a pathogenic mechanism or a phenotypic marker of predisposition to atherogenesis.     

Endothelial selectins and vascular cell adhesion molecule-1 promote hematopoietic progenitor homing to bone marrow

The adhesive mechanisms allowing hematopoietic progenitor cells (HPC) homing to the bone marrow (BM) after BM transplantation are poorly understood. We investigated the role of endothelial selectins and vascular cell adhesion molecule-1 (VCAM-1) in this process. Lethally irradiated recipient mice deficient in both P-and E-selectins (P/E−/−), reconstituted with minimal numbers (≤5 × 10⁴) of wild-type BM cells, poorly survived the procedure compared with wild-type recipients. Excess mortality in P/E−/− mice, after a lethal dose of irradiation, was likely caused by a defect of HPC homing. Indeed, we observed that the recruitment of HPC to the BM was reduced in P/E−/− animals, either splenectomized or spleen-intact. Homing into the BM of P/E−/− recipient mice was further compromised when a function-blocking VCAM-1 antibody was administered. Circulating HPC, 14 hr after transplantation, were greatly increased in P/E−/− mice treated with anti-VCAM-1 compared with P/E−/− mice treated with just IgG or wild-type mice treated with either anti-VCAM-1 or IgG. Our results indicate that endothelial selectins play an important role in HPC homing to the BM. Optimal recruitment of HPC after lethal doses of irradiation requires the combined action of both selectins and VCAM-1 expressed on endothelium of the BM.     

Plasma soluble adhesion molecules; intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and E-selectin levels in patients with isolated coronary artery ectasia

Plasma soluble adhesion molecules, intercellular adhesion molecule-1 (ICAM)-1, vascular cell adhesion molecule-1 (VCAM-1) and E-selectin leves of patients with isolated coronary artery ectasia (CAE), patients with obstructive coronary artery disease without CAE and subjects with angiographically normal coronary arteries were evaluated. Patients with isolated CAE were detected to have significantly higher levels of plasma soluble ICAM-1, VCAM-1 and E-selectin in comparison with patients with obstructive coronary artery disease without CAE (ICAM, 673 +/- 153 versus 381 +/- 106, respectively, P < 0.001; VCAM-1, 2366 +/- 925 versus 1136 +/- 208, respectively, P < 0.001; E-selectin, 74 +/- 21 versus 61 +/- 18, respectively, P = 0.01) and subjects with normal coronary arteries (ICAM-1, 673 +/- 153 versus 303 +/- 131, respectively, P < 0.001; VCAM-1, 2366 +/- 925 versus 729 +/- 231, respectively, P < 0.001; E-selectin, 74 +/- 21 versus 49 +/- 9, respectively, P < 0.001), suggesting the presence of a more severe and extensive chronic inflammation in the coronary circulation in patients with isolated CAE. BACKGROUND: The common coexistence of coronary artery ectasia (CAE) with coronary artery disease (CAD) suggests that it may be a variant of CAD. However, it is not clear why some patients with obstructive CAD develop CAE whereas most do not. Inflammation has been reported to be a major contributing factor to both obstructive and aneurysmatic vascular disorders and therefore, in the present study, the plasma soluble adhesion molecules, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin levels in isolated CAE were investigated. METHODS: The study population consisted of three groups: the first consisted of 32 patients with isolated CAE without stenotic lesion; the second of 32 patients with obstructive CAD without CAE; and the third group of 30 control subjects with normal coronary arteries. Coronary diameters were measured as the maximum diameter of the ectasic segment by use of a computerized quantitative coronary angiography analysis system. According to the angiographic definition used in the Coronary Artery Surgery Study, a vessel is considered to be ectasic when its diameter is > or =1.5 times that of the adjacent normal segment in segmental ectasia. Plasma soluble ICAM-1, VCAM-1 and E-selectin levels were measured in all patients and control subjects using commercially available enzyme-linked immunosorbent assay kits. RESULTS: Patients with isolated CAE were found to have significantly higher levels of plasma soluble ICAM-1, VCAM-1, and E-selectin in comparison with patients with obstructive CAD without CAE (ICAM, 673 +/- 153 versus 381 +/- 106, respectively; P < 0.001; VCAM-1, 2366 +/- 925 versus 1136 +/- 208, respectively; P < 0.001; E-selectin, 74 +/- 21 versus 61+/-18, respectively; P = 0.01) and control subjects with normal coronary arteries (ICAM-1, 673 +/- 153 versus 303 +/- 131, respectively;, P < 0.001; VCAM-1, 2366 +/- 925 versus 729 +/- 231, respectively; P < 0.001; E-selectin, 74 +/- 21 versus 49 +/- 9, respectively; P < 0.001). In addition, we detected statistically significant positive correlation between the total length of ectasic segments and the levels of plasma soluble ICAM-1 (r = 0.625; P < 0.001), VCAM-1 (r = 0.548; P = 0.001) and E-selectin (r = 0.390; P = 0.027). Multivariate logistic regression analysis revealed a significant independent relation between isolated CAE and ICAM-1 [odds ratio (OR) = 1.023; 95% confidence interval (CI) = 1.0048-1.0414; P = 0.0129] and VCAM-1 (OR = 1.0057; 95% CI = 1.0007-1.0106; P = 0.0240). CONCLUSIONS: We have shown that patients with isolated CAE have raised levels of plasma soluble ICAM-1, VCAM-1 and E-selectin in comparison with patients with obstructive CAD without CAE and control subjects with normal coronary arteries, suggesting the presence of a more severe and extensive chronic inflammation in the coronary circulation in these patients.     

Infection of endothelium with E1(-)E4(+), but not E1(-)E4(-), adenovirus gene transfer vectors enhances leukocyte adhesion and migration by modulation of ICAM-1, VCAM-1, CD34, and chemokine expression

Intravascular introduction of replication-deficient adenoviral vectors (Advectors) provides an ideal model of delivery of transgenes for the treatment of various vascular abnormalities. On the basis of the knowledge that Advectors can induce inflammatory responses after intravascular administration, we speculated that cellular activation by Advector infection could directly modulate the endothelial cell (EC) adhesion molecule/chemokine expression repertoire. Infection of human umbilical vein ECs or bone marrow microvascular ECs with an E1(-)E4(+) Advector resulted in the upregulation of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and CD34, but not E-selectin, P-selectin, CD36, CD13, CD44, HLA-DR or PECAM. Upregulation of ICAM-1, VCAM-1, and CD34 was apparent 12 hours after infection and persisted for weeks after infection. Selective induction of adhesion molecules was mediated by the presence of the E4 gene in the Advector, because infection of ECs with an E1(-)E4(-) Advector had no effect on adhesion molecule expression. ECs infected with E1(-)E4(+) Advector, but not those infected with E1(-)E4(-) Advector, supported the adhesion of leukocytes. Monoclonal antibodies to ICAM-1 and VCAM-1 inhibited adhesion of leukocytes to E1(-)E4(+)-infected ECS: Infection of the ECs with E1(-)E4(+) Advector, but not E1(-)E4(-) Advector, resulted in downregulation of expression of chemocytokines, including interleukin-8, MCP-1, RANTES, and GM-CSF. Nonetheless, a large number of leukocytes migrated through ECs infected with E1(-)E4(+), but not those infected with E1(-)E4(l-), in response to exogenous chemokines. These results demonstrate that infection of ECs with E1(-)E4(+) Advectors, but not E1(-)E4(-) Advectors, may directly augment inflammatory responses by upregulating expression of adhesion molecules and enhancing migration through Advector-infected ECs and suggest that E1(-)E4(-) Advectors may be a better choice for gene-transfer strategies directed to the ECS:     

Vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 serum level in patients with chest pain and normal coronary arteries (syndrome X)

BACKGROUND: Plasma levels of soluble vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) mediators of leukocyte adhesion to vascular endothelium may implicate in the pathogenesis of the syndrome of chest pain with normal coronary arteries. HYPOTHESIS: We attempted to determine whether markers of endothelial activation are raised in patients with chest pain and normal coronary arteries. METHODS: We measured plasma VCAM-1, ICAM-1 (ng/ ml) in 36 patients (34 men, 2 women, aged 62 +/- 9 years) with stable angina, coronary artery disease (CAD), and a positive response to exercise test; in 21 patients (6 men, 15 women, aged 56 +/- 9 years) with chest pain and normal coronary arteriograms (syndrome X); and in 11 healthy control subjects (8 men, 3 women, aged 49 +/- 14 years). RESULTS: Plasma ICAM-1 levels were significantly higher both in patients with CAD (mean +/- standard error of the mean) (328 +/- 26, p < 0.05), and in syndrome X (362 +/- 22, p < 0.01) than in controls (225 +/- 29). VCAM-1 levels were also higher in syndrome X (656 +/- 42 ng/ml) and in patients with CAD (626 +/- 42 ng/ml) than in controls (551 +/- 60, p = 0.09). CONCLUSIONS: ICAM-1 and VCAM-1 levels are increased both in patients with CAD and with syndrome X compared with control individuals. These findings may suggest the presence of chronic inflammation with involvement of the endothelium in patients with anginal chest pain and normal coronary angiograms.     

Both ICAM-1- and VCAM-1-integrin interactions are important in mediating monocyte adhesion to human saphenous vein

Atherosclerosis underlies late occlusion of human saphenous vein (HSV) coronary artery bypass grafts. Monocyte infiltration is implicated, but its mechanisms are unclear given that HSV normally expresses the ICAM-1 but not the VCAM-1 adhesion molecule. To define the mechanisms underlying monocyte adhesion, samples of HSV taken from coronary artery bypass graft patients were co-cultured with human monocytes and adherent monocytes were quantified by immunocytochemistry for CD68 on transverse sections. Pre-treatment of veins with anti-ICAM-1 antibodies reduced monocyte adhesion (monocytes/mm of section) from 7.2 +/- 1.5 to 3.1 +/- 0.7 (p < 0.05, n = 6), but the effect of anti-VCAM-1 was not significant (4.1 +/- 0.7). Paradoxically, pre-treatment of monocytes with either anti-beta(2)-integrins, the counter-receptor of ICAM-1, or anti-alpha(4) integrins, the counter-receptor of VCAM-1, significantly reduced adhesion (1.8 +/- 0.6 and 2.4 +/- 0.7, respectively, p < 0.05). These results were clarified by immunocytochemistry, which confirmed that VCAM-1 expression was absent in harvested vein but was induced in the endothelium during co-culture. Consistent with this, when anti-ICAM-1 or anti-VCAM-1 was present throughout co-culture, either of them reduced adhesion (from 4.2 +/- 0.9 to 2.3 +/- 0.5 and 2.2 +/- 0.4, respectively, p < 0.02, n = 8) and there was no further effect of adding both (2.0 +/- 0.5). These results demonstrate that both ICAM-1/beta(2) and VCAM-1/alpha(4) integrin interactions mediate monocyte adhesion to HSV, possibly as part of a common pathway. These experiments imply that either integrin might be targeted to reduce monocyte infiltration into HSV grafts.     

MRL/lpr lupus-prone mice show exaggerated ICAM-1-dependent leucocyte adhesion and transendothelial migration in response to TNF-alpha

OBJECTIVE: Endothelial activation and dysfunctional leucocyte-endothelial interactions are thought to play key roles in the pathogenesis of systemic lupus erythematosus (SLE). The object of this study was to investigate directly the effect of increased endothelial adhesion molecule expression on leucocyte-endothelial cell interactions, using the MRL/lpr mouse model. METHODS: Leucocyte rolling, arrest and transendothelial migration were quantified in the cremaster muscle microcirculation of 20-week-old MRL/lpr mice, using intravital microscopy. Endothelial adhesion molecule expression was quantified using intravenously injected radiolabelled monoclonal antibodies. RESULTS: Basal expression of intercellular adhesion molecule 1 (ICAM-1) by cremaster endothelium was 2-fold greater in MRL/lpr than in MRL/++ mice (P<0.05). There was a 1.6-fold increase in expression of vascular adhesion molecule 1 (VCAM-1), but no increase in E-selectin or P-selectin expression. Following intrascrotal injection of saline, no difference was detected in leucocyte-endothelial interactions between MRL/lpr and control MRL/++ mice. In contrast, intrascrotal injection of tumour necrosis factor alpha (TNF-alpha) (2 h test period) led to significantly increased numbers of adherent and extravasated leucocytes in MRL/lpr (5.98+/-0.71 and 5.45+/-0.34 leucocytes per 100 micro m vessel segment respectively) compared with MRL/++ mice (3.63+/-0.26 and 2.97+/-0.24 respectively, each P<0.05). Treatment of TNF-alpha-stimulated mice with anti-ICAM-1 F(ab')2 (YN1) abolished the difference between MRL/lpr and MRL/++ mice, whereas a negative control anti-DNP F(ab')2 had no effect. CONCLUSIONS: MRL/lpr lupus-prone mice show exaggerated ICAM-1-dependent leucocyte-endothelial interactions in response to TNF-alpha. Increased leucocyte-endothelial interactions due to endothelial priming could contribute to the clinical link between infection and flares of lupus disease activity.     

Percutaneous transluminal mitral valvuloplasty reduces circulating vascular cell adhesion molecule-1 in rheumatic mitral stenosis

BACKGROUND: The circulating levels of adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), have been demonstrated to be elevated in patients with rheumatic mitral stenosis (MS). However, the impact of percutaneous transluminal mitral valvuloplasty (PTMV) on the elevated circulating levels of VCAM-1 and ICAM-1 in patients with MS has never been investigated. METHODS: and results: A total of 19 patients with symptomatic MS undergoing PTMV were studied (group 1) [15 patients in chronic atrial fibrillation, and 4 patients in sinus rhythm]. The plasma levels of soluble VCAM-1 and ICAM-1 in the femoral vein and artery, and right and left atria before PTMV, and those in the peripheral venous blood at the 1-week and 4-week follow-ups after PTMV were determined by solid-phase sandwich enzyme-linked immunosorbent assay. The mitral valve area was calculated by means of the Doppler pressure half-time method. In addition, we measured plasma concentrations of soluble VCAM-1 and ICAM-1 in the peripheral venous blood samples obtained from 22 control patients (including 14 healthy volunteers in sinus rhythm [group 2] and 8 patients in chronic lone atrial fibrillation [group 3]). The plasma level of soluble VCAM-1 was significantly elevated in group 1 patients (1,205.4 +/- 462.4 ng/mL [mean +/- SD]) compared with group 2 (580.9 +/- 208.0 ng/mL) and group 3 patients (716.4 +/- 221.6 ng/mL) [p < 0.0001]. In group 1 patients, the plasma levels of soluble VCAM-1 and ICAM-1 in the left atrium did not differ from those in the right atrium, femoral vein, or femoral artery (p = 0.668 for VCAM-1, and p = 0.232 for ICAM-1). The area of mitral valve increased significantly after PTMV (1.08 +/- 0.14 cm(2) vs 1.48 +/- 0.33 cm(2), p < 0.0001). The mean left atrial pressure fell significantly after PTMV (22.9 +/- 5.2 mm Hg vs 17.7 +/- 6.0 mm Hg, p < 0.0001). The peripheral venous plasma level of soluble VCAM-1 obtained before PTMV fell significantly after PTMV (before, 1,205.4 +/- 462.4 ng/mL; 1 week after PTMV, 915.7 +/- 280.2 ng/mL; 4 weeks after PTMV, 859.0 +/- 298.7 ng/mL; p < 0.0001). CONCLUSIONS: In patients with moderate-to-severe MS, the venous plasma level of soluble VCAM-1 fell significantly after PTMV, and the elevated plasma soluble VCAM-1 concentration was associated with hemodynamic abnormality rather than with rheumatic activity.     

3-deazaadenosine prevents adhesion molecule expression and atherosclerotic lesion formation in the aortas of C57BL/6J mice

Adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) play an important role during the development of atherosclerosis. 3-Deazaadenosine (c(3)Ado), an adenosine analogue, inhibits endothelial-leukocyte adhesion and ICAM-1-expression in vitro. We hypothesized that c(3)Ado is able to prevent the expression of adhesion molecules and atherosclerotic lesion formation in female C57BL/6J mice. The animals were placed on an atherogenic diet with or without c(3)Ado for 9 weeks. Frozen cross sections of the proximal ascending aorta just beyond the aortic sinus were stained with oil red O, hematoxylin, and elastic van Gieson's stains and were analyzed by computer-aided planimetry for fatty plaque formation and neointimal proliferation. Monoclonal antibodies against CD11b (macrophages), VCAM-1, and ICAM-1 were used for immunohistochemistry. Mice on the atherogenic diet demonstrated multiple (5.4+/-1.6 per animal) lesions covering 3.4+/-2.8% of the endothelium and a marked neointima when compared with control mice (4501+/-775 versus 160+/-38 microm(2), P<0.001). Mice on the cholesterol-rich diet without c(3)Ado showed strong endothelial coexpression of ICAM-1 and VCAM-1. Moreover, there was a 10-fold increase in monocyte accumulation on the endothelial surface (33. 3+/-4.9 versus 3.8+/-1.2, P<0.004). In contrast, in mice treated with c(3)Ado, expression of ICAM-1 and VCAM-1 as well as monocyte adhesion and infiltration were almost completely inhibited. Furthermore, these mice did not show any fatty streak formation or neointima formation (125+/-32 microm(2)). Our results demonstrate that c(3)Ado can inhibit diet-induced fatty streak formation and the expression of endothelial ICAM-1 and VCAM-1 in C57BL/6J mice. This may provide a novel pharmacological approach in the prevention and treatment of atherosclerosis.     

胃肿瘤患者循环可溶性细胞间粘附分子-1和血管细胞粘附分子-1

AIM To elucidate the biological and clinical significance of sICAM-1 and sVCAM-1 in patients with gastric cancer.METHODS The serum levels of soluble ICAM-1 and VCAM-1 were measured with sandwith enzyme immunoassay.RESULTS In gastric cancer patients, soluble ICAM-1 and VCAM-1 concentrations were significantly elevated in comparision with those of healthy subjects (289.23μg/L±32.69μg/L vs 190.44μ/L±35.92μg/L,1430.88μg/L±421.71μg/L vs 727.24μg/L±157.68μg/L, respectively, P＜0.01). The increment in serum sICAM-1 and sVCAM-1 concentrations correlated well with the staging of gastric cancer. The serum levels of sICAM-1 and sVCAM-1 in patients of Ⅲ-Ⅳ stages were higher than those of Ⅰ-Ⅱ stages (346.60μg/L±92.10μg/L vs 257.54μg/L±32.77μg/L, 1800.60μg/L±510.76μg/L vs 1262.81μg/L±236.73μg/L). The levels of sICAM-1 and sVCAM-1 were correlated significantly (r=0.49,P＜0.01). The sICAM-1 and sVCAM-1 levels correlated positively with alkaline phophatase (r=0.63,0.71,P＜0.001) and white cell count (r=0.52,0.43, P＜0.01); but correlated negatively with serum albumin (r=-0.41, -0.49, P＜0.01).CONCLUSION The measurement of circulating ICAM-1 and VCAM-1 may bring additional prognostic information for patients with gastric cancer in varying stages.INTRODUCTIONTumor growth and metastasis involves a variety of cell-cell and cell-extracellular matrix interactions mediated by cell adhesion molecules. Currently, a number of cell adhesion molecules, such as intercellular adhesion molecules-1 (ICAM-1), vascular cell adhesion molecules-1 (VCAM-1), etc. have been found.ICAM-1 and VCAM-1 are members of the immunoglobulin supergene family which are cytokine-induced glycoproteins (IL-1, TNFα and IFNγ). Both of them have five or seven extracellular immunoglobulin-like domains, a single transmembranous domain and a short cytoplasmic tail[1,2]. The natural ligand of ICAM-1 or VCAM-1 is LFA-1 (CD11a) and Mac-1 (CD11b) or VLA-4, respectively[3]. ICAM-1 is a widely distributed protein on a variety of tissues, and can be detected in many cells such as macrophage, T- and B-cells, or fibroblasts, endothelial and epithelial cells. VCAM-1 is also a widely distributed protein and is constitutively expressed on tissue macrophage, dentritic cells in lymphoid tissue and skin, as well as on bone marrow fibroblasts and epithelial cells. Expression of VCAM-1 is inducible on vascular endothelial cells under pathological conditions[4].Recently, soluble forms of several adhesion molecules including ICAM-1 and VCAM-1 were found in serum of normal donors[5]. Abnormally high levels of them have been described in some solid malignant tumors, leukemia, autoimmune disease, infectious disease, etc.The present study was carried out to measure the circulating levels of sICAM-1 and sVCAM-1 in gastric cancer before treatment was given and to study their correlation with clinical, histological and routine laboratory parameters.     

VCAM-1 and ICAM-1 mediate leukocyte-endothelial cell adhesion in rat experimental colitis

BACKGROUND & AIMS: The molecular mechanisms responsible for leukocyte recruitment in experimental colitis are poorly understood. The aims of this study were to measure expression of endothelial intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) and to determine their role in leukocyte recruitment in experimental colitis. METHODS: Rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis and control rats were studied 1, 7, or 21 days after treatment. ICAM-1 and VCAM-1 expressions were measured by the double radiolabeled antibody technique. Leukocyte-endothelial cell interactions were determined in colonic venules by fluorescence intravital microscopy. Therapeutic effects of treatment with anti-VCAM-1 antibodies were also assessed. RESULTS: Colonic endothelial ICAM-1 was constitutively expressed and did not increase in colitic animals. In contrast, constitutive expression of VCAM-1 was low but markedly increased (6-fold) 1 and 7 days after induction of colitis. Increased colonic expression of VCAM-1 paralleled macroscopic damage score, myeloperoxidase activity, and increased leukocyte adhesion in colonic venules. The latter was significantly decreased by immunoneutralization of ICAM-1 and completely abrogated by immunoneutralization of VCAM-1. Long-term administration of anti-VCAM-1 antibody resulted in significant attenuation of colitis. CONCLUSIONS: Induction of colitis in rats by TNBS is followed by up-regulation of endothelial VCAM-1. VCAM-1 and constitutive ICAM-1 are major determinants of leukocyte recruitment to the inflamed intestine.     

Control of leukocyte rolling velocity in TNF-alpha-induced inflammation by LFA-1 and Mac-1.

Previously it was shown that beta(2)-integrins are necessary for slow leukocyte rolling in inflamed venules. In this study, mice that are deficient for either one of the beta(2)-integrins, alpha(L)beta(2) (LFA-1) or alpha(M)beta(2) (Mac-1), were used to determine which of the beta(2)-integrins are responsible for slowing rolling leukocytes. The cremaster muscles of these mice were treated with tumor necrosis factor-alpha and prepared for intravital microscopy. The average rolling velocities in venules were elevated in LFA-1(-/-) mice (11.0 +/- 0.7 microm/s) and Mac-1(-/-) mice (10.1 +/- 1.1 microm/s) compared to wild-type mice (4.8 +/- 0.3 microm/s; P <.05), but were lower than in CD18(-/-) mice (28.5 +/- 2.1 microm/s). When both LFA-1 and Mac-1 were absent or blocked, rolling velocity became dependent on shear rate and approached that of CD18(-/-) mice. In addition, leukocyte adhesion efficiency was decreased in LFA-1(-/-) mice to near CD18(-/-) levels, but decreased only slightly in Mac-1(-/-) mice. Thus, both LFA-1 and Mac-1 contribute to slowing down rolling leukocytes, although LFA-1 is more important than Mac-1 in efficiently inducing firm adhesion.