Overexpression Of Intercellular Adhesion Molecule-1 Research Articles

Mucin1 expression is enriched in the human stem cell fraction of cord blood and is upregulated in majority of the AML cases

Mucin1 is a membrane glycoprotein that is overexpressed in a variety of human cancers. Here, we analyzed the role of Mucin1 in human hematopoietic stem/progenitor cells as well as in acute myeloid leukemia (AML) cells. Mucin1 expression was determined within the normal stem cell and progenitor compartment, as well as in the AML CD34+ and CD34- subfractions of patient samples. Stem cells were enumerated in long-term culture-initiating cell (LTC-IC) assays in limiting dilution and progenitor frequencies in colony-forming cell (CFC) assays in methylcellulose, and consequences of elevated Mucin1 expression were studied using retroviral overexpression systems in cord blood (CB) CD34+ cells. Ten percent of CB and 5% of peripheral blood CD34+ cells expressed Mucin1. Retroviral overexpression of Mucin1 in CB CD34+ cells resulted in elevated stem cell and progenitor frequencies as determined in LTC-IC and CFC assays without affecting differentiation, which coincided with increased proliferation. Overexpression of intercellular adhesion molecule-1, a ligand for Mucin1, in MS5 stromal cells further increased LTC-IC frequencies. Mucin1 overexpression was associated with increased nuclear factor-kappaB p50 nuclear translocation, suggesting that Mucin1-induced phenotypes involve increased cell survival mechanisms. Finally, we observed increased Mucin1 expression in 70% of the AML cases (n=24), suggesting that elevated Mucin1 levels might be involved in regulating the proliferative potential of the immature leukemic compartment as well. Our data indicate that hematopoietic stem cells as well as CD34+ AML subfractions are enriched for Mucin1 expression, and that overexpression of Mucin1 in CB cells is sufficient to increase both progenitor and LTC-IC frequencies.

Artemisia asiatica extracts protect against ethanol‐induced injury in gastric mucosa of rats

Based on our previous studies that Artemisia asiatica extracts exert either antioxidative or cytoprotective actions against non-steroidal anti-inflammatory drugs or Helicobacter pylori-induced gastric mucosal injury, or imposes qualified ulcer healing in an acetic acid-induced gastric ulcer model, we investigated the protective effects of Artemisia asiatica extracts against ethanol-induced gastric mucosal injury. Sprague-Dawley rats received 4 g/kg body weight (BW) of absolute ethanol intragastrically, which produced visible hemorrhagic gastric lesions 60 min later. In this animal setting, the pretreatment of Artemisia extracts (30 or 100 mg/kg BW), 1 h before ethanol administration, significantly attenuated the source of gastric injury, which was assessed with gross and microscopic analysis (P < 0.01). Protection from alcohol-induced damage with Artemisia pretreatment was associated with significantly decreased lipid peroxidation, protecting gastric mucosa from glutathione depletion, as well as the inhibition of the cytochrome 2E1 ethanol-metabolizing enzyme. It attenuated the expressions of ethanol-induced pro-inflammatory cytokines, including interleukin (IL)-1beta and interferon-gamma, a weak activation of IL-10, the inhibition of the alcohol-induced overexpression of intercellular adhesion molecule-1, and the considerable induction of heat shock protein-72 expression in gastric mucosal homogenates. The data suggest that the ethanol extracts of Artemisia asiatica exerted significant protection from alcohol-induced gastric mucosal injury through bio-regulation, which is essential for cytoprotection and anti-inflammation.

Comparative effects of quercetin and its predominant human metabolites on adhesion molecule expression in activated human vascular endothelial cells

Adhesion of circulating monocytes to vascular endothelial cells, a critical step in both inflammation and atherosclerosis, is mediated by cross-linkage of adhesion molecules expressed on the surface of both cell types. Dietary flavonoids have been shown to have anti-inflammatory properties, decreasing the expression of cell adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) on endothelial cells. However, flavonoids are efficiently metabolised during absorption and the forms reaching the systemic circulation are glucuronidated, sulphated and methylated. Most previous in vitro studies of the effects of flavonoids have used the parent compounds at concentrations far higher than those physiologically achievable. We investigated the ability of quercetin and its human metabolites, at physiological concentrations (2 μmol/L and 10 μmol/L), to attenuate the inflammation-induced upregulated expression of VCAM-1, ICAM-1 and of the chemokine, monocyte chemoattractant protein-1 (MCP-1), in human umbilical vein endothelial cells (HUVECs), at the protein and transcript levels. Quercetin treatment reduced the inflammation-induced over-expression of VCAM-1 and ICAM-1 (protein and transcript) in HUVECs. Quercetin also inhibited MCP-1 gene expression. However, quercetin 3′-sulfate, quercetin 3-glucuronide and 3′-methylquercetin 3-glucuronide (isorhamnetin 3-glucuronide) generally exhibited either a reduced ability to inhibit the expression of these molecules compared with the parent aglycone or had no effect. However, all three metabolites inhibited VCAM-1 cell surface expression at 2 μmol/L. These results indicate that both quercetin and its metabolites, at physiological concentrations, can inhibit the expression of key molecules involved in monocyte recruitment during the early stages of atherosclerosis.

Protection ofVeratrum nigrum L. var. ussuriense Nakai alkaloidsagainst ischemia-reperfusion injury of the rat liver

To investigate the protective effects and possible mechanisms of Veratrum nigrum L.var. ussuriense Nakai alkaloids (VnA) on hepatic ischemia/reperfusion (I/R) injury in rats. Forty male Wistar rats were randomly divided into four experimental groups (n = 10 in each): (A) Control group (the sham operation group); (B) I/R group (pretreated with normal saline); (C) Small-dose (10 microg/kg) VnA pretreatment group; (D) Large-dose (20 microg/kg) VnA pretreatment group. Hepatic ischemia/reperfusion (Hepatic I/R) was induced by occlusion of the portal vein and the hepatic artery for 90 min, followed by reperfusion for 240 min. The pretreatment groups were administered with VnA intraperitoneally, 30 min before surgery, while the control group and I/R group were given equal volumes of normal saline. Superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity and nitric oxide (NO) content in the liver tissue at the end of reperfusion were determined and liver function was measured. The expression of intercellular adhesion molecule-1 (ICAM-1) and E-selectin (ES) were detected by immunohistochemical examinations and Western blot analyses. The results showed that hepatic I/R elicited a significant increase in the plasma levels of alanine aminotransferase (ALT: 74.53 +/- 2.58 IU/L vs 1512.54 +/- 200.76 IU/L, P < 0.01) and lactic dehydrogenase (LDH: 473.48 +/- 52.17 IU/L vs 5821.53 +/- 163.69 IU/L, P < 0.01), as well as the levels of MPO (1.97 +/- 0.11 U/g vs 2.57 +/- 0.13 U/g, P < 0.01) and NO (69.37 +/- 1.52 micromol/g protein vs 78.39 +/- 2.28 micromol/g protein, P < 0.01) in the liver tissue, all of which were reduced by pretreatment with VnA, respectively (ALT: 1512.54 +/- 200.76 IU/L vs 977.93 +/- 89.62 IU/L, 909.81 +/- 132.76 IU/L, P < 0.01, P < 0.01; LDH: 5821.53 +/- 163.69 IU/L vs 3015.44 +/- 253.01 IU/L, 2448.75 +/- 169.4 IU/L, P < 0.01, P < 0.01; MPO: 2.57 +/- 0.13 U/g vs 2.13 +/- 0.13 U/g, 2.07 +/- 0.05 U/g, P < 0.01, P < 0.01; NO: 78.39 +/- 2.28 micromol/g protein vs 71.11 +/- 1.73 micromol/g protein, 68.58 +/- 1.95 micromol/g protein, P < 0.05, P < 0.01). The activity of SOD (361.75 +/- 16.22 U/mg protein vs 263.19 +/- 12.10 U/mg protein, P < 0.01) in the liver tissue was decreased after I/R, which was enhanced by VnA pretreatment (263.19 +/- 12.10 U/mg protein vs 299.40 +/- 10.80 U/mg protein, 302.09 +/- 14.80 U/mg protein, P < 0.05, P < 0.05). Simultaneously, the histological evidence of liver hemorrhage, polymorphonuclear neutrophil infiltration and the overexpression of ICAM-1 and E-selectin in the liver tissue were observed, all of which were attenuated in the VnA pretreated groups. The results demonstrate that VnA pretreatment exerts significant protection against hepatic I/R injury in rats. The protective effects are possibly associated with enhancement of antioxidant capacity, reduction of inflammatory responses and suppressed expression of ICAM-1 and E-selectin.

Changes in Cerebral Vascular Reactivity Occur Early During Cardiopulmonary Bypass in the Rat

Cardiopulmonary bypass (CPB) is known to cause cerebrovascular dysfunction. The etiology of these complications is complex, but disruption of normal cerebral endothelial function as a consequence of inflammatory or hypoperfusion phenomena have been implicated. The aim of this study was to investigate the effect of CPB time on cerebrovascular reactivity and to investigate the correlation of these findings with measured inflammatory markers. Cardiopulmonary bypass was carried out for 30 or 60 minutes on two groups of rats. Sham groups underwent the same surgical procedure without CPB. The middle cerebral artery was harvested and prepared for assessment of induced endothelial and vascular smooth muscle cell responses. Systemic inflammation was evaluated by measuring tumor necrosis factor-alpha and immunohistochemical staining for intercellular adhesion molecule-1. Acetylcholine caused a dose-dependent vasodilation in the control groups that was absent in animals undergoing CPB (21.3% +/- 1.3% increase in diameter at 30 minutes in the sham group compared with 5.4% +/- 1.1% in the corresponding CPB group, p < 0.001). Significantly, this was apparent after only 30 minutes of CPB. Cardiopulmonary bypass did not alter the response to sodium nitroprusside (45.3% +/- 8.6% after 30 minutes in the sham group compared with 57.8% +/- 8.0% in the corresponding CPB group, p < 0.2). Furthermore, the contractile response to serotonin remained intact in all groups (32.9 +/- 4.6 and 27.6 +/- 2.6 at 30 and 60 minutes, respectively, in the sham groups compared with 23.1 +/- 1.6 and 28.0 +/- 4.4 in the corresponding CPB groups, p < 0.2). Cardiopulmonary bypass also led to an early and marked increase in tumor necrosis factor-alpha and overexpression of intercellular adhesion molecule-1. Cerebrovascular impairment appears early after the onset of CPB. The specific loss of acetylcholine-induced vasodilation suggests endothelial cell dysfunction rather than impaired vascular smooth muscle response to nitric oxide. This loss of endothelium-dependent regulatory factors after CPB may enhance vasoconstriction, impair cerebrovascular function, and contribute to neurologic injury after CPB.

Renoprotective effects of combination of angiotensin converting enzyme inhibitor with mycophenolate mofetil in diabetic rats

Previously it was shown that blocking of the renin-angiotensin system (RAS) by angiotensin converting enzyme (ACE) inhibitors, or suppression of inflammatory responses by immunosuppressive drugs such as mycophenolate mofetil (MMF) could attenuate renal injury in diabetic rats. Whether RAS blockade combined with an immunosuppressive drug provides superior renoprotection against diabetic nephropathy has not been clearly delineated. Diabetes was induced by injection of streptozotocin after uninephrectomy. Rats were randomly separated into five groups: control, diabetes, diabetes treated with enalapril (an ACE inhibitor, 10 mg/kg/d by gastric gavage), diabetes treated with MMF (10 mg/kg/d by gastric gavage), or diabetes treated with a combination of both agents and were followed for 8 weeks. 24 h urinary albumin excretion rate (AER) was determined, renal injury was evaluated, immunohistochemistry for ED-1 macrophage marker, intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) were performed, and expression of transforming growth factor (TGF)-beta1 protein was determined by Western blotting analysis. Diabetes was associated with a considerable increase in AER. Both enalapril and MMF retarded the increase in albuminuria, which was nearly completely abrogated by combination therapy. Increased glomerular volume and tubulointerstitial injury index in diabetic rats was attenuated by treatment with either enalapril or MMF and further reduced by the combination of the two. Elevated malondialdehyde levels in renal tissue were reduced by enalapril or MMF and, more effectively, by combined enalapril with MMF. Renal overexpression of ICAM-1 was not retarded by enalapril and attenuated by MMF or combined enalapril with MMF. Combination therapy was associated with a superior suppression of diabetes-induced macrophage recruitment and overexpression of MCP-1 and TGFbeta1 compared to either monotherapy in renal tissue. The combination of enalapril and MMF confers superiority over monotherapy in renoprotection, a mechanism which may be at least partly correlated with synergistic suppression of increased macrophage recruitment and overexpression of MCP-1 and TGF-beta1 in renal tissue in diabetic rats.

Protein Kinase C β Inhibitor LY333531 Attenuates Intercellular Adhesion Molecule-1 and Monocyte Chemotactic Protein-1 Expression in the Kidney in Diabetic Rats

In vitro studies have shown that activation of protein kinase C (PKC) is a key mediator of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) in a range of cell types and in response to high glucose, however, its role in the in vivo setting has not been clearly delineated. Streptozotocin-induced diabetic rats were treated with the PKC-beta isoform inhibitor LY333531 for 8 weeks. LY333531 treatment significantly attenuated increased urinary albumin excretion rate and glomerular volume and tubulointerstitial injury index as well as elevated PKC activity and PKC-beta protein expression in the kidney. Level of malondialdehyde was markedly higher and antioxidant enzyme activity such as superoxide diamutase and catalase as well as glutathione peroxidase were significantly lower in the kidney from diabetic rats than that of the control group. LY333531 administration could remit these changes. Increased macrophages recruitment as well as ICAM-1 and MCP-1 protein expression in the kidney were significantly inhibited by LY333531 in diabetic rats. It is concluded that mechanism of renoprotection of LY333531 may be correlated, at least partly, with suppression of increased macrophages recruitment and overexpression of ICAM-1 and MCP-1 in diabetic rats.

Prevention of early renal injury by mycophenolate mofetil and its mechanism in experimental diabetes

Previously it was shown that treatment with mycophenolate mofetil (MMF) attenuated renal inflammation and glomerular injury in a model of diabetes. However, the mechanism involved in the renoprotective effects of MMF in experimental diabetes has not been clearly delineated. Diabetes was induced by injection of streptozotocin (STZ) after uninephrectomy. Diabetic animals received no treatment or treatment with MMF (10 mg/kg once daily by gastric gavage) for 8 weeks, non-diabetic rats served as controls. Level of malondialdehyde (MDA) in renal tissue and urine as well as the activity of antioxidant enzymes (AOE) in renal tissue was determined. Renal injury was evaluated. Immunohistochemistry for ED-1 macrophages marker, intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) was performed. Expression of transforming growth factor (TGF)-β1 protein was determined by Western blotting analysis. Treatment with MMF had no effect on blood glucose level, but did prevent increased urinary albumin excretion and glomerular damage in diabetic rats. Oxidative stress was reduced by MMF treatment, as indicated by a reduction in MDA level in renal tissue and urine. Activity of AOE such as glutathione peroxidase (GSH-PX) was markedly elevated while superoxide dismutase (SOD) and catalase (CAT) were not changed by MMF treatment. In diabetic animals receiving no treatment, there were increases in ED-1-positive cells, ICAM-1 expression and MCP-1 expression in glomeruli and tubulointerstitium, which were effectively suppressed by MMF treatment. Western blotting analysis showed that the expression of TGF-β1 protein was increased by 1.92-fold in renal tissue in diabetic rats, and MMF treatment significantly reduced the increased expression of TGF-β1 protein by 45%.Our data suggest that MMF treatment ameliorates early renal injury via the inhibition of oxidative stress and overexpression of ICAM-1, MCP-1 and TGF-β1 in renal tissue in diabetic rats.

Mild hypothermia reduces expression of intercellular adhesion molecule‐1 (ICAM‐1) and the accumulation of neutrophils after acid‐induced lung injury in the rat

The pathophysiology of the acute phase of acid-induced lung injury (AILI) has been elucidated. However, once acute respiratory distress syndrome (ARDS) develops, the mortality rate remains high and there is, as yet, no effective therapy. There are reports that application of mild hypothermia is an effective treatment for ARDS. In this study, we hypothesize that mild hypothermia inhibits activation of neutrophils and expression of intercellular adhesion molecule-1 (ICAM-1) in an injured lung. We studied the effects of mild hypothermia on the expression of ICAM-1 and the accumulation of neutrophils after AILI in the rat. Male Sprague-Dawley rats were randomly allocated to one of the four groups: control normothermic group, induced mild hypothermia group, acid-instilled normothermic group, and acid-instilled group with mild hypothermia. At 6 h after instillation of acid, lungs were removed to measure neutrophil activity and to detect the expression of ICAM-1 in each group. Oxygenation in acid-instilled rats was significantly impaired as compared to that in non-instilled groups, but induction of mild hypothermia gradually improved oxygenation. Expression of ICAM-1 was enhanced in the acid-instilled normothermic group. By contrast, no overexpression of ICAM-1 and its mRNA was detected in the acid-instilled hypothermic group. In addition, accumulation of neutrophils was markedly inhibited after exposure to mild hypothermia irrespective of the instillation of acid. Our data suggest mild hypothermia can inhibit the adhesion, activation, and accumulation of neutrophils during the acute phase of AILI in the rat and may have the potential to reduce ongoing inflammation of ALI or ARDS.

Intercellular adhesion molecule-1 and vascular endothelial growth factor expression kinetics in macrophage-derived foam cells

Macrophage-derived foam cells seem to play an important role during inflammatory response of atherosclerosis, in which the overexpression of intercellular adhesion molecule-1 (ICAM-1) and vascular endothelial growth factor (VEGF) are associated with the early and later pathological changes in foam cell formation. In this study, we investigated the expression kinetics of ICAM-1 and VEGF in macrophage-derived foam cells. The foam cell model was established through incubating the human monocyte line (U937 cells) with oxidized-low density lipoprotein (ox-LDL). Up-regulated expressions of ICAM-1 and VEGF were analyzed in protein and mRNA levels in U937 foam cells by flow cytometry, ELISA, and Northern blot. Kinetic studies showed the deferent kinds of expression curves in dose response and time course. The expression dose-kinetics demonstrated that the ICAM-1 showed the peak expression induced by ox-LDL 50 mg/L, while VEGF levels increased in a dose-dependent manner with the maximum level induced by ox-LDL 200 mg/L. Time-kinetic studies revealed that the ICAM-1 levels showed the peak expression in 12 h while VEGF expression increased in a time-dependent manner with the maximum level in 48 h. These results proved that both ICAM-1 and VEGF expressions were enhanced in the macrophage-derived foam cells, but ICAM-1 expression increased earlier than the up-regulation of VEGF; low dose of ox-LDL mainly up regulated ICAM-1 expression, while high dose mainly increased the VEGF expression.

Heparin-binding EGF-like growth factor downregulates expression of adhesion molecules and infiltration of inflammatory cells after intestinal ischemia/reperfusion injury

Background/Purpose: This study examined whether heparin-binding epidermal growth factor (EGF) like growth factor (HB-EGF), a proven intestinal cytoprotective molecule, exerts its protective effects through modulation of adhesion molecule expression and inflammatory cell infiltration, important pathogenic mediators of ischemia/reperfusion (I/R) injury. Methods: Total midgut I/R injury in rats was achieved by occlusion of the superior mesenteric artery for 90 minutes followed by reperfusion. Rats were treated intraluminally with 600 μg/kg HB-EGF or with PBS 45 minutes after the onset of ischemia. Four- or 24-hours post-I/R, ileum was harvested and processed for immunhistochemical detection of P-/E-selectins, intercellular adhesion molecule–1 (ICAM-1)/vascular cell adhesion molecule–1 (VCAM–1), and polymorphonuclear cells (PMN)/macrophages (MΦ). Results: P-/E-selectins were significantly induced in vascular endothelia 4 hours after I/R injury compared with normal intestine. HB-EGF treatment significantly down-regulated the expression of P-/E-selectins. I/R-injured intestine displayed overexpression of ICAM-1 and VCAM-1, which were significantly down-regulated by HB-EGF treatment. Lastly, I/R injury caused significant infiltration of PMN and MΦ into wounded tissue 24 hours after I/R compared with normal intestine. HB-EGF treatment significantly decreased PMN and MΦ infiltration into the injured tissue. Conclusions: HB-EGF intestinal cytoprotection is mediated, in part, by down-regulation of expression of adhesion molecules and infiltration of PMN and MΦ after intestinal I/R injury. J Pediatr Surg 38:434-439. Copyright 2003, Elsevier Science (USA). All rights reserved.

Leukemic target susceptibility to natural killer cytotoxicity: relationship with BCR-ABL expression

AbstractChronic myeloid leukemia is a clonal myeloproliferative expansion of transformed primitive hematopoietic progenitor cells characterized by high-level expression of BCR-ABL chimeric gene, which induces growth factor independence. However, the influence of BCR-ABL expression on cell-mediated cytotoxicity is poorly understood. In the present study, we asked whether BCR-ABL expression interferes with leukemic target sensitivity to natural killer (NK) cell cytolysis. Our approach was based on the use of 2 BCR-ABL transfectants of the pluripotent hematopoietic cell line UT-7 expressing low (UT-7/E8, UT-7/G6) and high (UT-7/9) levels of BCR-ABL. As effector cells, we used CD56bright, CD16−, CD2− NK cells differentiated in vitro from CD34 cord blood progenitors. We demonstrated that BCR-ABL transfectants UT-7/9 were lysed by NK cells with a higher efficiency than parental and low UT-7/E8.1 and UT-7/G6 transfectants. This enhanced susceptibility to lysis correlated with an increase in expression of intercellular adhesion molecule 1 (ICAM-1) by target cells. Treatment of UT-7/9 cells by STI571 (a specific inhibitor of the abl kinase) resulted in a decrease in NK susceptibility to lysis and ICAM-1 down-regulation in target cells. Furthermore, the constitutive activation of nuclear factor-κB (NF-κB) detected in BCR-ABL transfectant UT-7/9, was significantly attenuated when cells were treated by STI571. Interestingly, inhibition of NF-κB activation by BAY11-67082 (a specific NF-κB inhibitor) resulted in down-regulation of ICAM-1 expression and a subsequent decrease in NK-induced killing of UT-7/9 transfectants. Our results show that oncogenic transformation by BCR-ABL may increase susceptibility of leukemic progenitors to NK cell cytotoxicity by a mechanism involving overexpression of ICAM-1 as a consequence of NF-κB activation.

Expression of intercellular adhesion molecule-1 on the surface of peripheral blood and decidual lymphocytes of women with pregnancy-induced hypertension

Objective: If overexpression of intercellular adhesion molecule-1 (CD54) on lymphocytes exists it could have important implications for the pathophysiology of pregnancy-induced hypertension (PIH). Study design: CD54 “in vitro” expression (described as (%) of CD54+cells and CD54 mean fluorescence intensity, MFI) on the peripheral blood and decidual lymphocytes of pregnant with pre-eclampsia (PE) ( n=16), transient hypertension (TH) ( n=12), and controls ( n=9). Results: The percent (%) of CD54+peripheral blood lymphocytes, CD54 MFI on them and CD54 MFI on decidual lymphocytes were increased especially in PE. During PE the (%) of CD54 decidual lymphocytes correlated negatively with platelet count. In TH the positive correlation between the blood pressure and the (%) of CD54 peripheral blood lymphocytes as well as CD54 MFI on decidual lymphocytes were found. Conclusions: (1) PIH, especially PE, is accompanied by overexpression of intercellular adhesion molecule-1 (ICAM-1) on peripheral blood and decidual lymphocytes studied “in vitro”, (2) Some of the parameters studied seem to correlate with clinical markers of PIH intensity but this fact needs further investigations using larger subject groups.

Endothelial Dysfunction and Salt-Sensitive Hypertension in Spontaneously Diabetic Goto-Kakizaki Rats

Endothelial dysfunction is associated with hypertension, hypercholesterolemia, and heart failure. We tested the hypothesis that spontaneously diabetic Goto-Kakizaki (GK) rats, a model for type 2 diabetes, exhibit endothelial dysfunction. Rats also received a high-sodium diet (6% NaCl [wt/wt]) and chronic angiotensin type 1 (AT(1)) receptor blockade (10 mg/kg PO valsartan for 8 weeks). Compared with age-matched nondiabetic Wistar control rats, GK rats had higher blood glucose levels (9.3+/-0.5 versus 6.9+/-0.2 mmol/L for control rats), 2.7-fold higher serum insulin levels, and impaired glucose tolerance (all P<0.05). Telemetry-measured mean blood pressure was 15 mm Hg higher in GK rats (P<0.01) compared with control rats, whereas heart rates were not different. Heart weight- and kidney weight-to-body weight ratios were higher in GK rats (P<0.05), and 24-hour albuminuria was increased 50%. Endothelium-mediated relaxation of noradrenaline-precontracted mesenteric arterial rings by acetylcholine was impaired compared with the control condition (P<0.05), whereas the sodium nitroprusside-induced relaxation was similar. Preincubation of the arterial rings with the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester and the cyclooxygenase inhibitor diclofenac inhibited relaxations to acetylcholine almost completely in GK rats but not in Wistar rats, suggesting that endothelial dysfunction can be in part attributed to reduced relaxation via arterial K(+) channels. Perivascular monocyte/macrophage infiltration and intercellular adhesion molecule-1 overexpression were observed in GK rat kidneys. A high-sodium diet increased blood pressure by 24 mm Hg and 24-hour albuminuria by 350%, induced cardiac hypertrophy, impaired endothelium-dependent relaxation further, and aggravated inflammation (all P<0.05). The serum level of 8-isoprostaglandin F(2alpha), a vasoconstrictor and antinatriuretic arachidonic acid metabolite produced by oxidative stress, was increased 400% in GK rats on a high-sodium diet. Valsartan decreased blood pressure in rats fed a low-sodium diet and prevented the inflammatory response. In rats fed a high-sodium diet, valsartan did not decrease blood pressure or improve endothelial dysfunction but protected against albuminuria, inflammation, and oxidative stress. As measured by quantitative autoradiography, AT(1) receptor expression in the medulla was decreased in GK compared with Wistar rats, whereas cortical AT(1) receptor expression, medullary and cortical angiotensin type 2 (AT(2)) receptor expressions, and adrenal ACE and neutral endopeptidase expressions were unchanged. A high-sodium diet did not influence renal AT(1), AT(2), ACE, or neutral endopeptidase expressions. In valsartan-treated GK rats, the cortical and medullary AT(1) receptor expressions were decreased in the presence and absence of a high-sodium diet. A high-sodium diet increased plasma brain natriuretic peptide concentrations in presence and absence of valsartan treatment. We conclude that hypertension in GK rats is salt sensitive and associated with endothelial dysfunction and perivascular inflammation. AT(1) receptor blockade ameliorates inflammation during a low-sodium diet and partially protects against salt-induced vascular damage by blood pressure-independent mechanisms.

Upregulated Expression of Rat Heart Intercellular Adhesion Molecule-1 in Angiotensin II- but Not Phenylephrine- Induced Hypertension.

-Intercellular adhesion molecule-1 (ICAM-1), part of an immunoglobulin-like superfamily of adhesion molecules, is involved in several cardiovascular diseases. We investigated whether in vivo angiotensin II (Ang II) increases ICAM-1 in rats. Sprague-Dawley rats were infused with vehicle or Ang II (750 µg. kg(-1). d(-1) SC) for 7 days. The contribution of Ang II receptors to ICAM-1 expression was investigated with a nonpeptide Ang II type 1 (AT(1)) receptor antagonist losartan (30 mg. kg(-1). d(-1) in drinking water). Systolic blood pressure was elevated in Ang II-treated animals compared with sham-treated controls, and losartan blocked this increase. Tumor necrosis factor (TNF)-alpha (5 µg/kg IP bolus), a prototype inducer of ICAM-1, was administered as a positive control for ICAM-1 expression. After treatment, hearts were frozen in liquid nitrogen; homogenates were subjected to SDS-PAGE and immunoblotted with an anti-rat ICAM-1 monoclonal antibody. We detected a predominantly high-molecular-weight band in homogenates from non-TNF-alpha-treated rats, which was enhanced by 80+/-5% in TNF-alpha-treated rats. This band measured approximately 200 kDa, which is the molecular weight of ICAM-1 in its native dimer form. The same band was detected in homogenates from sham and Ang II-treated rats, with the latter showing a 150+/-10% increase in ICAM-1 versus sham controls. Immunoprecipitation of rat heart homogenates with anti-rat ICAM-1 antibody resulted in a dominant band of the same molecular weight as samples not treated with antibody. Losartan prevented enhanced expression of ICAM-1 in the presence of Ang II but had no effect on basal ICAM-1 expression. Phenylephrine, an alpha-agonist (3 mg. kg(-1). d(-1) ), was infused for 1 week but had no effect on ICAM-1 expression, even though systolic blood pressure was elevated to the same level as in rats treated with Ang II. Thus, heart ICAM-1 expression is enhanced via AT(1) receptor activation independent of hypertension. Ang II-induced ICAM-1 expression was time and dose dependent, with maximal expression occurring within 5 to 7 days at 100 to 750 µg/kg Ang II. Immunohistochemical staining demonstrated markedly increased ICAM-1 levels in the perivascular area in Ang II-infused rats. Monocyte/macrophage accumulation was significantly greater in Ang II-treated rat hearts than in sham-treated hearts (10+/-1; P:<0.001; n=5). Thus during inflammation, overexpression of ICAM-1 may contribute to cardiovascular damage in diseases characterized by increased activity of the renin-angiotensin system.

一時的ラット局所脳虚血モデルにおける虚血後脳低温療法の脳損傷に対する保護効果

Intraischemic mild hypothermia has been shown to be neuroprotective in transient focal ischemia. As a more clinical relevant issue, the effect of postischemic hypothermia on cerebral infarction in a rat model of reversible focal ischemia was investigated. Rats were subjected to 2 hours of middle cerebral artery (MCA) occlusion followed by 22 hours of reperfusion under the following protocols : (1) rats were treated with normothermia (37.0°C, 4 hours) and then housed in a room maintained at 25°C for 18 hours; and (2) rats were treated with hypothermia (33°C, 4hours) and then housed in a cold room maintained at 5°C for 18 hours. After 24 hours of the MCA occlusion, a significant reduction in volume of infarction was found in the postischemic hypothermia group compared to the normothermic group. Postischemic hypothermia also significantly reduced the accumulation of poymorphonuclear leukocytes (PMNLs) and suppressed the overexpression of intercellular adhesion molecule-1 (ICAM-1) mRNA. In conclusion, ischemic brain damage can be reduced by a mild and prolonged postischemic hypothermia in a focal model of transient cerebral ischemia. The neuroprotective mechanism of postischemic hypothermia may be mediated by suppression of leukocytemediated inflammation after ischemia and reperfusion.

Expression and regulation of intercellular adhesion molecule-1 (ICAM-1) in organotypic cultures of rat liver tissue

Background/Aims: The objective of the present study was to analyze the expression and regulation of intercellular adhesion molecule-1 (ICAM-1) in organotypic cultures of rat liver slices, which preserve the normal microenvironment of liver cells. Methods: Rat liver slices were maintained in culture for 15 min to 24 h and examnied for ICAM-1 expression by immunohistochemistry and Western blotting in basal conditions and after stimulation with 1000 IU/ml interferon-γ (IFNγ), 1000 IU/ml tumor necrosis factor-α (TNFα) and 50 μg/ml endotoxin. Immunohistochemical results were evaluated using a semiquantitative scoring system. Results: In uncultured slices, ICAM-1 was not detected on hepatocytes. In unstimulated liver slices maintained in organotypic culture, ICAM-1 was induced at the surface of scattered hepatocytes (score at 15 min, 0.33±0.47 and at 24 h, 1.17±0.69). After 4 h of stimulation, a significant increase in ICAM-1 expression by hepatocytes and adjacent sinusoidal cells, but not by intra-hepatic biliary epithelial cells, was observed for IFNγ (score: 2.35±0.47) and endotoxin (score: 2.67±0.47), but not with TNFα (score: 0.66±0.47). After 24 h of stimulation, a further increase in the extent of ICAM-1 expression by hepatocytes was observed for IFNγ (score: 3.67±0.47) and endotoxin (score: 4.0±0.0), and a significant overexpression of ICAM-1 by hepatocytes was detectable after treatement with TNFα (score: 3.67±0.47). Conclusions: In rat liver organotypic cultures, TNFα, IFNγ and endotoxin induce the expression of ICAM-1 in hepatocytes and adjacent sinusoidal endothelial cells, but not in portal tracts.

Overexpression of intercellular adhesion molecule-1 (ICAM-1) in pancreatic adenocarcinoma in comparison with normal pancreas.

To elucidate the role of intercellular adhesion molecules (ICAMs), which has not been well understood in pancreas, we investigated the localization and expression of ICAM-1 by immunohistochemistry and in situ hybridization (ISH) in pancreatic adenocarcinoma and in normal pancreas. The localizations of ICAM-2 and ICAM-3 were also investigated by immunohistochemistry. In normal pancreas, acinar cells, duct epithelial cells, and Langerhans islet cells failed to stain with anti-ICAM-1, anti-ICAM-2, and anti-ICAM-3 antibodies. These cells showed no expression of ICAM-1 mRNA. On the other hand, various percentages of carcinoma cells were stained with anti-ICAM-1 antibody, while no carcinoma cells were stained with anti-ICAM-2 and anti-ICAM-3 antibodies. ICAM-1 mRNA expression was also observed in carcinoma cells, and ICAM-1 mRNA expression was associated with localization of the ICAM-1 protein. These results suggest that ICAM-1 expression is up-regulated in pancreatic adenocarcinoma cells and that ICAM-1 is involved in malignant processes in pancreas.

Serum and ascitic levels of soluble intercellular adhesion molecule-1 in patients with alcoholic liver cirrhosis: relation to biochemical markers of disease activity and alcohol intake.

The overexpression of intercellular adhesion molecule-1 (ICAM-1) has been shown to be involved in the pathogenesis of various necroinflammatory diseases, including alcoholic hepatitis. Shedding of this molecule from cell surfaces results in a circulating form, soluble ICAM-1 (sICAM-1). In this work, the serum and ascitic concentrations of sICAM-1 were studied in relation to clinical and laboratory data in patients with alcoholic liver cirrhosis of different disease activities. Elevated circulating concentrations of this adhesion molecule were found in all cirrhotic patients, the highest in those with superimposed severe alcoholic hepatitis, and the levels in regularly drinking cirrhotics without severe alcoholic hepatitis were likewise significantly higher than in those who had stopped drinking. The serum sICAM-1 concentration was best related to the serum AST activity, and also exhibited significant correlations with the prothrombin activity, serum bilirubin, albumin, peripheral leukocyte count. Maddrey's discriminant function value, Child grading, and antecedent alcohol consumption. Multivariate regression analysis revealed that the serum AST and prothrombin activities were independent predictors of the circulating sICAM-1 concentration. The concentration of sICAM-1 in the uninfected ascitic fluid of cirrthotics was about seven times lower than that in the serum; the ratio of its ascitic and serum levels was lower than that of the ascitic and serum total protein concentrations. These data contradict a significant intraperitoneal production of the molecule. It is concluded that the serum sICAM-1 level may be useful as a marker for the current disease activity (the severity of underlying acute necroinflammatory reactions) in alcoholic liver cirrhosis.

Overexpression of intercellular adhesion molecule-1 (ICAM-1) and MHC class II antigen on hypertrophic nerve trunks suggests an immunopathologic response in Hirschsprung's disease

The pathogenesis of Hirschsprung's disease (HD) is not fully understood. The authors studied expression of intercellular adhesion molecule-1 (ICAM-1) and major histocompatibility complex (MHC) class II antigen in the resected bowel specimes of 18 patients with HD who had no evidence of enterocolitis and in eight age- and site-matched controls, using indirect immunohistochemistry. There was strong expression of ICAM-1 and MHC class II antigen on hypertrophic nerve trunks, in both the submucous and myenteric plexuses of the aganglionic colon. The transition zone showed strong expression of ICAM-1 and MHC class II antigen on small ganglia in the myenteric and submucous plexuses. However, no staining of ganglia or nerve fibers was found in the submucous and myenteric plexuses of the colon from controls or in the ganglionic colon from patients with HD. The expression of both antigens on hypertrophic nerve trunks suggests the presence of an immunologic response in the pathogenesis of HD.