Dexamethasone down-regulates the inflammatory mediators but fails to reduce the tissue injury in the lung of acute pancreatitis rat models

Pulmonary complications are frequent in the course of acute pancreatitis. We investigate the effects of dexamethasone on lung injury in mild and severe AP. Mild and severe acute pancreatitis was induced in rats by bile-pancreatic duct obstruction and infusion of 3.5% sodium taurocholate into the bile-pancreatic duct, respectively. Dexamethasone (1 mg/kg) was given by intramuscular injection 1 h after acute pancreatitis. Plasma amylase activity was measured to evaluate the pancreas damage. Lungs were harvested for analysing mRNA expression of monocyte chemoattractant protein-1 (MCP-1), cytokine-induced neutrophil chemoattractant (CINC), P-selectin and intercellular adhesion molecule-1 (ICAM-1), myeloperoxidase (MPO) activity (as index of neutrophil infiltration) and histological examination. Dexamethasone reduced the hyperamylasemia and hindered the pulmonary upregulation of MCP-1, CINC, P-selectin and ICAM-1, in both mild and severe acute pancreatitis. Despite this, dexamethasone treatment failed to reduce MPO activity and histological alterations developed in lungs during acute pancreatitis, either in bile-pancreatic duct obstruction or sodium taurocholate model. We conclude that pulmonary local factors different from inflammatory mediators contribute to leukocyte recruitment, so that although dexamethasone down-regulated the lung expression of chemokines and adhesion molecules during acute pancreatitis it was not able to prevent leukocyte infiltration, which could be responsible for maintaining the lung injury in either mild or severe acute pancreatitis.     

Effects of a Metalloproteinase that Truncates P-selectin Glycoprotein Ligand on Neutrophil-induced Cardiac Dysfunction in Ischemia/Reperfusion

This study was designed to test the effects of polymorphonuclear leukocytes (PMNs) in the presence and absence of a P-selectin blocker, mocarhagin, in provoking cardiac dysfunction in isolated perfused rat hearts following ischemia and reperfusion. Control rat hearts not subjected to ischemia were perfused without blood cells for 80 min. Additional control rat hearts were perfused with 100×10⁶PMNs in the presence and absence of 0.2μg/ml mocarhagin over a 5-min perfusion followed by a 45-min observation period. No significant reduction in coronary flow (CF), left ventricular developed pressure (LVDP), or the first derivative of LVDP (dP/dtmax) was observed at the end of the observation period in any non-ischemic group. Similarly, global ischemia (I) for 20 min followed by 45 min of reperfusion (R) produced no sustained effects on the final recovery of any of these parameters in any group of hearts perfused in the absence of PMNs. I/R hearts perfused with PMNs exhibited decreases of 50–60% in all measurements of cardiac function (P<0.001). These PMN perfused I/R hearts also exhibited marked increases in cardiac myeloperoxidase (MPO) activity indicating a significant PMN infiltration, and enhanced P-selectin expression on the coronary microvascular endothelium. All cardiodynamic effects as well as MPO accumulation and PMN infiltration were attenuated markedly by the metalloproteinase, mocarhagin, which inhibits P-selectin-mediated cell adhesion by cleaving its high-affinity receptor, PSGL-1, present on neutrophils. These results provide evidence that neutrophils provoke post-reperfusion cardiac dysfunction, and that this may be largely due to P-selectin-induced adherence of neutrophils to the endothelium.     

Role of oral blockade of platelet glycoprotein IIb/IIIa on neutrophil activation in patients with acute coronary syndromes

Orbofiban is a unique antiplatelet agent that inhibits the binding of fibrinogen to gycoprotein (GP) IIb/IIIa integrin receptors and thus prevents platelet aggregation induced by various agents. However, recent studies indicate that treatment with orbofiban does not reduce the incidence of recurrent ischemic events. The mechanisms underlying the lack of benefit of orbofiban in patients with acute coronary syndromes are not completely clear. The purpose of this study was to characterize the effects of orbofiban on cellular activation (neutrophil superoxide generation) and surface expression of adhesion molecules of circulating neutrophils (CD18, CD11b, and L-selectin) and platelets (P-selectin and GP IIb/IIIa) in patients with acute coronary syndromes. After 5–7 days, orbifiban (50 mg BID) did not reduce PMN adhesion molecule expression and ex vivo-stimulated PMN superoxide generation—as was observed in the placebo group, without orbofiban. In contrast, orbofiban induced marked reductions in GP IIb/IIIa and P-selectin expressions after 5–7 days of treatment. The sustained neutrophil activation observed with orbofiban may have a role on the recurrent thrombotic events observed with orbofiban treatment in the OPUS-TIMI 16 trial.     

Role of superoxide anion in the pathogenesis of cytokine-induced myocardial dysfunction in dogs in vivo.

OBJECTIVE: Although studies in vitro have implicated oxygen-derived free radicals as possible mediators of inflammatory cytokine-induced cell injury, the role of the radicals in the cytokine-induced myocardial dysfunction in vivo remains unclear. The present study was designed to address this point in our novel canine model of cytokine-induced myocardial dysfunction in vivo. METHODS: Studies were performed in mongrel dogs, in which microspheres (MS, 15 microns in diameter) with and without interleukin-1 beta (IL-1 beta) were injected into the left main coronary artery (control and IL-1 beta group). Left ventricular ejection fraction (LVEF) was evaluated by echocardiography for 1 week. RESULTS: Immediately after the intracoronary injection of MS (10(6)/kg), LVEF equally decreased to approximately 30% in both the control and IL-1 beta group. While LVEF rapidly recovered within 2 days in the control group, it remained depressed in the IL-1 beta group until day 7 (p < 0.0001 vs. control group). Pretreatment with OPC-6535 (an inhibitor of superoxide production) before (2 mg/kg i.v.) and 1 and 2 days after IL-1 beta MS application (1 mg/kg i.v.) prevented the IL-1 beta-induced myocardial dysfunction. Superoxide production in the myocardium was significantly higher in the IL-1 beta group than in the control group at day 2 (p < 0.01), and OPC-6535 significantly suppressed the IL-1 beta-induced superoxide production (p < 0.01). An HPLC assay showed that nitrotyrosine, a marker of the formation of peroxynitrite by superoxide anion and nitric oxide, was present in the myocardium treated with IL-1 beta but not in that with control MS. OPC-6535 abolished the IL-1 beta-induced formation of myocardial nitrotyrosine. CONCLUSION: These results indicate that superoxide anion and the resultant formation of peroxynitrite may substantially be involved in the pathogenesis of the cytokine-induced myocardial dysfunction in dogs in vivo.     

Reduced plaque formation induced by rosiglitazone in an STZ-diabetes mouse model of atherosclerosis is associated with downregulation of adhesion molecules

Adhesion molecules have been implicated in the development and progression of cardiovascular disease, which is highly prevalent in people with diabetes. Adhesion molecules can mediate adhesion of leukocytes to the endothelium. Furthermore, P-selectin expressed on platelets is able to mediate the adhesion of leukocytes to platelets. In this study, we examine the in-vivo and in-vitro effects of rosiglitazone with particular emphasis on three important adhesion molecules (VCAM-1, ICAM-1 and P-selectin). In the aorta of STZ-diabetic apolipoprotein E-deficient (apoE KO) mice, rosiglitazone significantly reduced both total and arch plaque area. The mechanism for this appeared to be reduced macrophage infiltration into the atherosclerotic plaque which was also associated with reduced mRNA levels for VCAM-1, ICAM-1, MCP-1 and P-selectin in the aorta. In-vitro studies revealed reduced cell adhesion of monocytic cells (THP-1) to fibrinogen and endothelial cells (HUVEC) after incubation with rosiglitazone. Furthermore, the reduction in leukocyte adhesion also correlated with significant reductions in mRNA levels for VCAM-1, ICAM-1 and P-selectin indicating that reduced macrophage infiltration in atherosclerotic plaques may occur as a result of a direct effect of rosiglitazone on adhesion molecules in both monocytes and endothelial cells. Thus, we have shown that rosiglitazone appears to have direct anti-atherosclerotic effects in an animal model of diabetes-associated atherosclerosis which are at least partly due to effects on VCAM-1, ICAM-1, MCP-1 and P-selectin expression which leads to decreased leukocyte adhesion and macrophage infiltration.     

Effect of nuclear factor kappa B on intercellular adhesion molecule-1 expression and neutrophil infiltration in lung injury induced by intestinal ischemia/reperfusion in rats

AIM:To investigate the role of nuclear factor kappa B(NF-κB) in the pathogenesis of lung injury induced byintestinal ischemia/reperfusion (I/R),and its effect onintercellular adhesion molecule-1 (ICAM-1) expressionand neutrophil infiltration.METHODS:Twenty-four Wistar rats weredivided randomly into control,I/R and pyrrolidinedithiocarbamate (PDTC) treatment groups,n=8 ineach.I/R group and PDTC treatment group receivedsuperior mysenteric artery (SMA) occluding for 1 h andreperfusion for 2 h.PDTC group was administrated withintraperitoneal injection of 2% 100 mg/kg PDTC 1 hbefore surgery.Lung histology and bronchia alveoluslung fluid (BALF) protein were assayed.Serum IL-6,lungmalondialdehyde (MDA) and myeloperoxidase (MPO) aswell as the expression level of NF-κB and ICAM-1 weremeasured.RESULTS:Lung injury induced by intestinal I/R,wascharacterized by edema,hemorrhage and neutrophilinfiltration as well as by the significant rising of BALFprotein.Compared to control group,the levels of serumIL-6 and lung MDA and MPO increased significantly in I/Rgroup (P=0.001).Strong positive expression of NF-κBp65 and ICAM-1 was observed.After the administrationof PDTC,the level of serum IL-6,lung MDA and MPOas well as NF-κB and ICAM-1 decreased significantly(P<0.05) when compared to I/R group. CONCLUSION:The activation of NF-kB plays animportant role in the pathogenesis of lung injury inducedby intestinal I/R through upregulating the neutrophilinfiltration and lung ICAM-1 expression.PDTC as aninhibitor of NF-kB can prevent lung injury induced byintestinal I/R through inhibiting the activity of NF-kB.     

Cytokines in Sickle Cell Disease

Sickle red cells express adhesion molecules including integrin ₄β₁, CD36, band 3 protein, sulfated glycolipid, Lutheran protein, phosphatidylserine and integrin-associated protein. The proadhesive sickle cells may bind to endothelial cell P-selectin, E-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), CD36 and integrins leading to its activation. Monocytes also activate endothelium by releasing proinflammatory cytokines like tumor necrosis factor alpha (TNF-) and interleukin 1β (IL-1β). Sickle monocytes also express increased surface CD11b and cytoplasmic cytokines TNF and IL-1β indicating activated state. Polymorphonuclear leukocytes (PMNs) are also activated with reduced L-selectin expression, enhanced CD64 expression and elevated levels of sL-selectin, sCD16 and elastase resulting in increased adhesiveness to the endothelium. Platelets are also activated and secrete thrombospondin (TSP) and cytokine IL-1. They also form platelet- monocytes aggregates causing endothelial cell P-selectin expression. Endothelial cell activation by these multiple mechanisms leads to a loss of vascular integrity, expression of leukocyte adhesion molecules, change in the surface phenotype from antithrombotic to prothrombotic, excessive cytokine production and upregulation of HLA molecules. Furthermore, contraction of these activated endothelial cells leads to exposure of extracellular matrix proteins, such as TSP, laminin, and fibronectin and their participation in adhesive interactions with bridging molecules from the plasma such as von Willebrand factor (vWf) released from endothelial cells, ultimately culminating in vasoocclusion and local tissue ischemia, the pathognomonic basis of vasoocclusive crisis.     

Identification of IL-1β-induced messenger RNAs in rat pancreatic beta cells by differential display of messenger RNA

Abstract Aims/hypothesis. Interleukin-1β is a putative mediator of pancreatic beta-cell dysfunction and damage in Type I (insulin-dependent) diabetes mellitus. To better understand the molecular mechanisms involved in IL-1β effects, we carried out a differential display of mRNA by RT-PCR to identify novel cytokine-regulated genes. Methods. Fluorescence activated cell sorting-purified rat pancreatic beta-cells were exposed for 6 or 24 h to IL-1β. Differentially expressed cDNA bands were cloned and then identified by comparing their sequences with data from the GenBank. Differential gene expression was confirmed by RT-PCR using specific primers. Results. Interleukin-1β increased the expression of adenine nucleotide translocator-1, phospholipase D-1 and cytokine-induced neutrophil chemoattractant-1 and decreased expression of the protein tyrosine phosphatase-like protein IA-2. Interleukin-1β-induced differential expression of these genes in beta cells was confirmed by RT-PCR. In additional studies, IL-1β was shown to induce chemokines other than cytokine-induced neutrophil chemoattractant-1, including cytokine-induced neutrophil chemoattractant-3 and monocyte chemotactic protein-1. Conclusion/interpretation. Our observations indicate that IL-1β modifies the expression of several genes in pancreatic beta cells. These genes may affect both function, viability and beta-cell recognition by the immune system. Functional characterization of the mRNAs which have been identified could facilitate a better understanding of the mechanisms leading to beta-cell destruction in Type I diabetes. [Diabetologia (1999) 42: 1199–1203] Received: 4 June 1999 and in revised form: 1 July 1999     

Anti-endothelial cell IgG antibodies from patients with Wegener's granulomatosis bind to human endothelial cells in vitro and induce adhesion molecule expression and cytokine secretion

Objective. To elucidate the role of antiendothelial cell antibodies (AECA) in vascular inflammation in patients with Wegener's granulomatosis (WG). Methods. IgG fractions from 3 AECA-positive WG patients, IgG from 3 AECA-negative WG patients, and IgG from healthy donors were tested for their ability to: a) bind to endothelial cells and to display complement-dependent or antibody-dependent cellular cytotoxicity, b) modulate cell membrane expression of adhesion molecules, as evaluated by cytofluorometry and by immunoenzymatic assay, and c) induce the secretion of interleukin-1β (IL-1β), IL-6, IL-8, and monocyte chemotactic protein 1 (MCP-1). Results. We found that AECA IgG from WG patients do not display any significant cytotoxicity but are able to up-regulate the expression of E-selectin, intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 and to induce the secretion of IL-1β, IL-6, IL-8, and MCP-1. Conclusion. AECA in patients with WG could play a potential pathogenetic role by activating endothelial cells, and thus facilitating leukocyte recruitment and adhesion to endothelial surfaces, rather than by displaying a cytotoxic activity.     

Effect of nuclear factor kappa B on intercellular adhesionrnolecule-1 expression and neutrophil infiltration in lung injury induced by intestinal ischemia/reperfusion in rats

AIM: To investigate the role of nuclear factor kappa B(NF-κB) in the pathogenesis of lung injury induced by intestinal ischemia/reperfusion (I/R), and its effect on intercellular adhesion molecule-1 (ICAM-1) expression and neutrophil infiltration.METHODS: Twenty-four Wistar rats were divided randomly into control, I/R and pyrrolidine dithiocarbamate (PDTC) treatment groups, n = 8 in each. I/R group and PDTC treatment group received superior mysenteric artery (SMA) occluding for 1 h and reperfusion for 2 h. PDTC group was administrated with intraperitoneal injection of 2% 100 mg/kg PDTC 1 h before surgery. Lung histology and bronchia alveolus lung fluid (BALF) protein were assayed. Serum IL-6, lung malondialdehyde (MDA) and myeloperoxidase (MPO) as well as the expression level of NF-κB and ICAM-1 were measured.RESULTS: Lung injury induced by intestinal I/R, was characterized by edema, hemorrhage and neutrophil infiltration as well as by the significant rising of BALF protein. Compared to control group, the levels of serum IL-6 and lung MDA and MPO increased significantly in I/R group (P=0.001). Strong positive expression of NF-κB p65 and ICAM-1 was observed. After the administration of PDTC, the level of serum IL-6, lung MDA and MPO as well as NF-κB and ICAM-1 decreased significantly(P＜ 0.05) when compared to I/R group.CONCLUSION: The activation of NF-κB plays an important role in the pathogenesis of lung injury induced by intestinal I/R through upregulating the neutrophil infiltration and lung ICAM-1 expression. PDTC as an inhibitor of NF-κB can prevent lung injury induced by intestinal I/R through inhibiting the activity of NF-κB.     

No rationale for a diagnostic ratio in left ventricular hypertrabeculation/noncompaction

IntroductionTo study the possible anti-inflammatory effect of hydrogen-rich saline (H₂ saline) on rat hearts with regional myocardial ischemia and reperfusion (I/R).MethodsSixty-six rats were equally randomized to three groups: sham-operated group, I/R group (control group) and I/R plus H₂ saline treatment group. Myocardial I/R was established by occlusion of the left anterior descending (LAD) coronary artery for 30 min and reperfusion for 24 h.ResultsH₂ saline treatment attenuated I/R-induced cardiac cell apoptosis, presenting as significant improvement of heart function parameters 24 h after reperfusion, including left ventricular systolic pressure (LVSP), left ventricular diastolic pressure (LVEDP), +(dP/dt)max and ?(dP/dt)max. It also decreased neutrophil infiltration, 3-nitrotyrosine level, expression of intercellular adhesion molecule 1(ICAM-1) and myeloperoxidase (MPO) activity in the area at risk zones (AAR) of rat hearts subjected to regional myocardial I/R, and attenuated the increase of I/R induced proinflammatory cytokine tumor necrosis factor-α (TNF-a) and interleukin-1β (IL-1b) levels in the AAR.ConclusionH₂ saline has an anti-inflammatory effect on rat hearts with regional myocardial I/R.     

Cilostazol inhibits high glucose-mediated endothelial-neutrophil adhesion by decreasing adhesion molecule expression via NO production

OBJECTIVE: Endothelial-neutrophil adhesion is crucial for vascular injury, the major cause of diabetic vascular complications. On the other hand, platelet aggregation inhibitors, frequently used for diabetic patients with intermittent claudication, have been shown to decrease the incidence of atherosclerosis-mediated diseases (acute myocardial infarction and stroke). However, whether these agents act directly on the endothelial reactions to hyperglycemia remains unclear. Therefore, we examined their direct effects on endothelial-neutrophil adhesion and expression of endothelial adhesion molecules induced by high glucose. METHODS AND RESULTS: After human endothelial cells were cultured in high glucose medium, neutrophils from healthy volunteers were added and allowed to adhere for 30 min. Adhered neutrophils were quantified by measuring their myeloperoxidase (MPO) activities, and surface expression of endothelial adhesion molecules was determined with an enzyme immunoassay. Of the platelet aggregation inhibitors tested, only cilostazol significantly attenuated the adhesion through decreasing expression of intercellular adhesion molecule-1 (ICAM-1) and P-selectin. In addition, nitric oxide (NO) synthase inhibitors reduced the inhibitory effects of cilostazol, but a protein kinase C (PKC) activator did not. CONCLUSIONS: Cilostazol may act directly on endothelial cells to inhibit expression of adhesion molecules and neutrophil adhesion induced by high glucose through increasing NO production.     

川芎嗪减轻大鼠心肌缺血再灌注损伤炎症反应及机制

目的观察川芎嗪预处理对大鼠心肌缺血再灌注损伤炎症反应的影响并探讨其可能的机制。方法 48只雄性SD大鼠随机分为假手术组、缺血再灌注组、川芎嗪组、左旋-硝基-精氨酸甲酯组以及川芎嗪+左旋-硝基-精氨酸甲酯组,假手术组左前降支近端穿线但不结扎,其余四组给予结扎前降支缺血35 min,再灌注120 min。光镜观察大鼠心肌组织结构变化,测定缺血心肌组织超氧化物歧化酶活性和丙二醛含量及髓过氧化物酶、白细胞介素1β、一氧化氮含量,逆转录聚合酶链反应和免疫印迹法测定心肌内皮型一氧化氮合酶mRNA和蛋白的表达水平。结果与缺血再灌注组相比,川芎嗪预处理能减少心肌白细胞浸润,增加心肌组织超氧化物歧化酶活性,降低丙二醛含量及髓过氧化物酶活性,降低白细胞介素1β水平,增加一氧化氮含量及心肌内皮型一氧化氮合酶mRNA和蛋白的表达水平,左旋-硝基-精氨酸甲酯显著抑制上述指标的变化并取消了川芎嗪所致的内皮型一氧化氮合酶mRNA和蛋白表达水平的增加。结论川芎嗪预处理能减少大鼠心肌缺血再灌注损伤的炎症反应,其机制可能与上调内皮型一氧化氮合酶表达,增加内源性一氧化氮水平有关。     

Cardioprotective effects of a novel proteasome inhibitor following ischemia and reperfusion in the isolated perfused rat heart

Ischemia followed by reperfusion in the presence of polymorphonuclear leukocytes (PMNs) results in cardiac contractile dysfunction as well as myocardial injury. These effects are due in large part to endothelial dysfunction leading to an upregulation of cell adhesion molecules and subsequent neutrophil induced cardiac injury. The proteasome inhibitor, PS-519, has been shown to attenuate leukocyte-endothelial cell interactions. We tested the effects of PS-519 on neutrophil mediated cardiac dysfunction in ischemia/reperfusion. This study examines the effects of PS-519 in a neutrophil dependent isolated perfused rat heart model of ischemia (I) (20 min) and reperfusion (R) (45 min). Administration of PS-519 (0.01, 0.1, 0.3, 1.0 mg/kg) to I/R hearts perfused with PMNs improved coronary flow, and preserved left ventricular developed pressure (LVDP) and + dP/dt max as indices of cardiac contractile function. At 1.0 mg/kg, PS-519 treated hearts exhibited a final LVDP of 98 +/- 3% of initial compared to 52 +/- 8% in I/R hearts receiving only vehicle (P < 0.001). In addition, PS-519 significantly reduced PMN accumulation in the ischemic myocardium from 25.1 +/- 2.1 PMNs/mm2 in untreated hearts to 7.3 PMNs/mm2, and attenuated P-selectin surface expression on coronary vascular endothelium from 7.1 +/- 0.3% to 1.4 +/- 0.2% (P < 0.01). These results provide evidence that PS-519 is a potent and effective cardioprotective agent that inhibits P-selectin leukocyte-endothelial cell interactions and preserves cardiac contractile function and coronary perfusion following myocardial ischemia and reperfusion.     

Role of P-selectin and intercellular adhesion molecule-1 in TNB-induced colitis in rats

It has been proposed that neutrophil-endothelial cell interactions mediated by adhesion molecules are involved in the pathogenesis of inflammatory bowel disease. The objective of the present study was to determine the effects of monoclonal antibodies (MAbs) directed against endothelial adhesion molecules, P-selectin and intercellular adhesion molecule-1 (ICAM-1), in rats with colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNB). Colonic inflammation was induced by administering an enema of TNB dissolved in 50% ethanol (120 mg/ml) to male Wistar rats (at a total volume of 0.25 ml per rat) after a 48-hour fast. Anti-P-selectin MAb or anti-ICAM-1 MAb was injected via the tail vein at a dose of 1 mg/kg after the induction of colitis. Rats in the control group received nonbinding mouse immunoglobulin G1. The plasma level of soluble P-selectin showed an increase within 48 h after the TNB enema. Colonic inflammation was assessed at 1 week after TNB administration. The colonic damage score and the wet weight of the colon were significantly decreased by treatment with either MAb. The increase of myeloperoxidase (MPO) activity, an index of neutrophil accumulation, and the increase of thiobarbituric acid-reactive substances (TBA-RS), an index of lipid peroxidation, in the colonic mucosa were inhibited by both MAbs. These results suggest that neutrophil-endothelial cell interactions via P-selectin and ICAM-1 play an important role in the development of TNB-induced colitis in rats.     

Cardiomyocyte Toll-like receptor 4 is involved in heart dysfunction following septic shock or myocardial ischemia

Toll-like receptors are expressed in immune cells and cardiac muscle. We examined whether the cardiac Toll-like receptor 4 (TLR4) is involved in the acute myocardial dysfunction caused by septic shock and myocardial ischemia (MI). We used wild type mice (WT), TLR4 deficient (TLR4-ko) mice and chimeras that underwent myeloablative bone marrow transplantation to dissociate between TLR4 expression in the heart (TLR4-ko/WT) and the immunohematopoietic system (WT/TLR4-ko). Mice were injected with lipopolysaccharide (LPS) (septic shock model) or subjected to coronary artery ligation (MI model) and tested in vivo and ex vivo, for function, histopathology proinflammatory cytokine and TLR4 expression. WT mice challenged with LPS or MI displayed reduced cardiac function, increased myocardial levels of IL-1β and TNF-α and upregulation of mRNA encoding TLR4 prior to myocardial leukocyte infiltration. TLR4 deficient mice sustained significantly smaller infarctions as compared to control mice at comparable areas at risk. The cardiac function of TLR4-ko mice was not affected by LPS and demonstrated reduced suppression by MI compared to WT. Chimeras deficient in myocardial TLR4 were resistant to suppression induced by LPS and the heart function was less depressed, compared to the TLR4-ko, following MI in the acute phase (4 h). In contrast, hearts of chimeras deficient in immunohematopoietic TLR4 expression were suppressed both by LPS and MI, exhibiting increased myocardial cytokine levels, similar to WT mice. We concluded that cardiac function of TLR4-ko mice and chimeric mice expressing TLR4 in the immunohematopoietic system, but not in the heart, revealed resistance to LPS and reduced cardiac depression following MI, suggesting that TLR4 expressed by the cardiomyocytes themselves plays a key role in this acute phenomenon.     

LipoxinA4 attenuates myocardial ischemia reperfusion injury via a mechanism related to downregulation of GRP-78 and caspase-12 in rats

This study aims to determine the effect of Lipoxin (LX)A₄ on myocardial ischemia reperfusion injury (MIRI) in rats and the related molecular mechanisms. Male SD rats were divided into six groups. The sham operation groups (groups C1, C2) were injected with 2 ml/kg normal saline before and after coronary artery threading, respectively. The MIRI group (groups I/R1, I/R2) were injected with normal saline before and after MIRI, respectively. The LXA₄ groups (groups LX1, LX2) were injected with LXA₄ before and after MIRI treatment, respectively. The hematoxylin–eosin staining and ultrastructural changes of cardiac muscle were observed. The serum levels of interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor (TNF) α and cardiac troponin I (cTnI) were measured before open-chest operation and at the end of the experiment. The mRNA and protein levels of GRP-78 and caspase-12 were determined in each group. The myocardial cell apoptosis, myeloperoxidase (MPO), superoxide dismutase (SOD), and malondialdehyde (MDA) contents were detected. The mRNA and protein levels of GRP-78 and caspase-12, the apoptosis, the serum IL-1β, IL-6, IL-10, TNF-α, and cTnI concentrations, MPO, SOD, MDA contents were significantly increased in groups I/R1, I/R2, LX1, and LX2 compared with those in groups C1 and C2 (P < 0.05). The mRNA and protein expression levels of GRP-78 and caspase-12 in groups LX1 and LX2 were lower than those in groups I/R1 and I/R2. Compared with group I/R1 and I/R2, the myocardial neutrophil infiltration and ultrastructure damage were significantly less in groups LX1 and LX2. GRP-78 and IL-10 are expressed both extracellularly and intracellularly, but are mainly expressed in the cytoplasms. In the absence of MIRI, LXA₄ has no detectable effect on GRP-78 and caspase-12 expression. Before and after MIRI, application of LXA₄ significantly inhibits neutrophil activation, and attenuates myocardial inflammatory injury and oxidative stress. LXA₄ downregulates the mRNA and protein expression of GRP-78 and caspase-12. LXA₄ could play a role in myocardial protection via a mechanism related to downregulation of GRP-78 and caspase-12, and inhibition of apoptosis.     

Correlation of soluble adhesion molecules in the peripheral blood of scleroderma patients with their in situ expression and with disease activity

Objective. To correlate serum levels of the soluble adhesion molecules intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), E-selectin, and P-selectin with (a) clinical disease activity and progression and (b) the in situ expression and distribution of these adhesion molecules in lesional skin, in patients with systemic sclerosis (SSc). Methods. Serum samples from 12 SSc patients and 36 healthy controls were examined by enzymelinked immunosorbent assay. Immunohistologic staining was carried out on cryostat sections of lesional skin. Results. Patients whose SSc was in the early inflammatory stage or who had prominent disease progression showed elevated serum levels of soluble adhesion molecules. Serum levels correlated positively with the expression of these molecules on endothelial cells and fibroblasts in lesional skin. Conclusion. Serum levels of soluble ICAM-1, VCAM-1, P-selectin, and, to a lesser degree, E-selectin correlate well with their in situ activity and with clinical disease activity. These parameters therefore provide a useful tool for the characterization of disease stage, progression, and prognosis in SSc.     

Indomethacin-induced small intestinal injury is ameliorated by cilostazol,a specific PDE-3 inhibitor

Abstract

Background. Neutrophil migration, one of the major factors predisposing to nonsteroidal anti-inflammatory drugs (NSAIDs)-induced intestinal lesions, consists of several steps, including interaction with P-selectin from platelets. Cilostazol, a specific phosphodiesterase (PDE)-3 inhibitor, suppresses the expression of P-selectin from platelets and reduces interaction between platelets and leukocytes, leading to inflammatory amelioration in several disease models. We tried to clarify the therapeutic effectiveness of cilostazol for NSAID-induced small intestinal lesions. Subjects and methods. 1) Anti-PSGL-1 antibody (2 mg/kg) or cilostazol (100 mg/kg) was administered to mice one hour before Indomethacin (IND, 2.5 mg/kg) administration for 4 days to evaluate small intestinal lesions. 2) IND-induced migratory behaviors of neutrophils and platelets were evaluated in intestinal vessels by an intravital microscopy. Results. i) IND induced small intestinal lesions with an increase in MPO activity. Anti-PSGL-1 antibody and cilostazol ameliorated intestinal lesions along with suppression of MPO activity. ii) Intravital microscopy revealed that administration of IND increased migration of platelet-bearing neutrophils. Cilostazol treatment ameliorated neutrophil migration by blocking interaction between platelets and neutrophils. Conclusion. Our results suggest that enhanced platelets-bearing neutrophil migration is critically involved in the pathogenesis of IND-induced small intestinal lesions and suggest a potential application of cilostazol for prevention of NSAID-induced small intestinal lesions.