Expression of monocyte chemoattractant protein 1 in human inflamed gingival tissues.

Gingival inflammation is initiated by bacterial colonization on the tooth surface. It is characterized by infiltration of mononuclear cells, a common feature of many forms of chronic inflammation. Monocyte chemoattractant protein 1 (MCP-1) is the predominant monocyte chemoattractant secreted by a variety of different cells in vitro. For this report, we examined MCP-1 expression in bacterially induced gingival inflammation by immunohistochemistry and in situ hybridization. The cell types expressing MCP-1 are identified as vascular endothelial cells and monocytes/macrophages. Correlation analysis shows that the number of cells expressing MCP-1 is related to the degree of inflammation. Our finding that MCP-1 is expressed in inflamed gingival tissue suggests that MCP-1 plays an important role in the recruitment of monocytes and amplification of inflammatory signals in bacterially induced inflammation.     

Roles and relationship of macrophages and monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 in the ischemic and reperfused rat heart

Reperfusion injury is a troublesome and unresolved problem in acute myocardial infarction and is believed to be associated with inflammatory reactions in which various types of cells and cytokines participate, in particular, macrophages and monocyte chemoattractant protein-1 (MCP-1). We designed this study to clarify the role and relationship of macrophages and MCP-1 in ischemic and reperfused heart. The number and distribution of macrophages and MCP-1 messenger RNA (mRNA) in the ischemic and reperfused rat heart were examined with in situ hybridization and immunohistochemistry. Myocardial samples were obtained at several times. In situ hybridization was performed with digoxigenin-labeled antisense RNA probe for rat MCP-1 mRNA, and immunohistochemistry was performed with antimacrophage antibody. Double staining with in situ hybridization and immunohistochemistry was also performed. The number of MCP-1 mRNA-positive cells increased after reperfusion and peaked at 3 hours after reperfusion. Early infiltration of ischemic tissues by macrophages was also observed at the time of the absence of an increase of MCP-1 mRNA-positive cells, and this infiltration was not significantly accelerated by reperfusion, but by ischemia itself. The numbers of both MCP-1 mRNA-positive cells and macrophages increased in the ischemic marginal region over time. From the result of double staining, and based on the cellular morphology and the distribution, the majority of MCP-1 mRNA-positive cells appeared to be activated macrophages. This suggests that macrophages may not be attracted to cardiac tissue only by MCP-1 and that MCP-1 may have some roles other than attracting macrophages into ischemic heart. It also suggests that macrophages and MCP-1 may play an important role in reperfusion injury and that MCP-1 may be one of the key molecules of reperfusion injury. These observations may contribute to the development of a new therapeutic approach to the prevention of reperfusion injury.     

Potential role for monocyte chemotactic protein-4 (MCP-4) in monocyte/macrophage recruitment in acute renal inflammation

The CC chemokine, monocyte chemoattractant protein-4 (MCP-4), is an important chemoattractant for monocytes and T cells. Recent data indicate a role in renal inflammation. This study has used in situ hybridization and immunohistochemical analysis of cryostat sections of biopsy material taken from patients with acute renal allograft rejection and vasculitic glomerulonephritis to demonstrate renal expression of MCP-4, both at message and protein level. MCP-4 was primarily expressed at peritubular, periglomerular, and perivascular sites, irrespective of the inflammatory condition, and was associated with infiltrating CD3-positive lymphocytes and CD68-positive monocyte/macrophages. In addition, proximal tubular epithelial cells grown in culture from cortical fragments of human kidney showed low levels of constitutive MCP-4 expression, detectable by western blotting; this expression of MCP-4 was up-regulated in response to the pro-inflammatory cytokines, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). CCR3-, CCR5- and CCR2-expressing leukocyte populations were identified at sites of MCP-4 expression. Double-staining techniques revealed that CC chemokine receptor-expressing cells were primarily CD68-positive. These studies suggest an important role for MCP-4 in the recruitment and retention of monocytes/macrophages in renal inflammation.     

Monocyte chemotactic protein-1, -2, and -3 are distinctively expressed in portal tracts and granulomata in primary biliary cirrhosis: implications for pathogenesis

The monocyte chemotactic proteins (MCPs) form a distinct structurally related subclass of C-C chemokines. MCPs select specific target cells due to binding to a distinct set of chemokine receptors and because of their effects on monocytes, and may participate in the process of granuloma formation during bacterial and/or mycobacterial infections. The aetiology of primary biliary cirrhosis (PBC) is still unclear, although bacterial infection and autoimmune processes have been implicated. In this study, the expression of three of the most potent monocyte chemoattractants, MCP-1, -2, and -3, was examined in patients with PBC and the data were compared with results for other liver diseases including primary sclerosing cholangitis (PSC), chronic viral hepatitis C, hepatic sarcoidosis, and normal liver. MCP-1 was expressed mainly in biliary epithelial cells of all liver specimens, irrespective of the cause of disease. Some mononuclear leukocytes in the portal tract expressed MCP-1 in all the disease groups examined and there were no significant differences in frequency between these groups. In contrast, more than 80% of PBC livers showed MCP-2- and MCP-3-positive mononuclear leukocyte infiltration in portal tracts, particularly around the bile ducts, whereas such cells were far less frequent in the other disease groups or in normal livers. Epithelioid granulomata of PBC patients contained MCP-2- and MCP-3-positive cells at their edge. In double staining experiments, more than 60% of the MCP-positive mononuclear cells co-expressed CD68, suggesting that a proportion of MCP-2- and MCP-3-positive cells are derived from monocytes. These monocytes expressing MCP-2 and MCP-3 may be responsible for the chemotactic activity of more monocytes. Such an expression pattern of MCP-1, -2 and -3 in portal tracts seems to be distinctive for PBC. This pattern underlines the importance of MCP-1, -2, and -3 in the recruitment of monocytes and possibly T lymphocytes into portal tracts, around the injured bile ducts, and into epithelioid granulomata in PBC. The data further implicate bacterial materials derived from bile in the overall pathogenesis of PBC.     

Enhanced production of the chemotactic cytokines interleukin-8 and monocyte chemoattractant protein-1 in human abdominal aortic aneurysms.

Inflammatory leukocytes play a central role in the pathogenesis of human atherosclerotic disease, from early atherogenesis to the late stages of atherosclerosis, such as aneurysm formation. We have shown previously that human abdominal aortic aneurysms are characterized by the presence of numerous chronic inflammatory cells throughout the vessel wall (Am J Pathol 1990, 137: 1199-1213). The signals that attract lymphocytes and monocytes into the aortic wall in aneurysmal disease remain to be precisely defined. We have studied the production of the chemotactic cytokines interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) by aortic tissues obtained from 47 subjects. We compared the antigenic production of these cytokines by explants of: 1) human abdominal aneurysmal tissue, 2) occlusive (atherosclerotic) aortas, and 3) normal aortas. IL-8, which is chemotactic for neutrophils, lymphocytes, and endothelial cells was liberated in greater quantities by abdominal aortic aneurysms than by occlusive or normal aortas. Using immunohistochemistry, macrophages, and to a lesser degree endothelial cells, were found to be positive for the expression of antigenic IL-8. Similarly, MCP-1, a potent chemotactic cytokine for monocytes/macrophages, was released by explants from abdominal aortic aneurysms in greater quantities than by explants from occlusive or normal aortas. Using immunohistochemistry, the predominant MCP-1 antigen-positive cells were macrophages and to a lesser extent smooth muscle cells. Our results indicate that human abdominal aortic aneurysms produce IL-8 and MCP-1, both of which may serve to recruit additional inflammatory cells into the abdominal aortic wall, hence perpetuating the inflammatory reaction that may result in the pathology of vessel wall destruction and aortic aneurysm formation.     

Evidence for increased expression of eotaxin and monocyte chemotactic protein-4 in atopic dermatitis

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with tissue eosinophilia and the activation of T lymphocytes. The novel eosinophil chemoattractants, eotaxin and monocyte chemotactic protein (MCP)-4, are up-regulated at sites of allergic inflammation, yet their contribution to the pathophysiologic mechanisms of AD remains to be determined. OBJECTIVE: We sought to investigate the expression of eotaxin and MCP-4 in acute and chronic lesions from patients with AD and to determine their relationship to the numbers of resident inflammatory cells. METHODS: With use of in situ hybridization, the expression of eotaxin and MCP-4 messenger RNA (mRNA) in skin biopsy specimens from patients with acute and chronic AD skin lesions was compared with that of uninvolved skin from these patients and skin from healthy volunteers. RESULTS: There was a constitutive expression of eotaxin and MCP-4 mRNA in skin biopsy specimens from healthy subjects. Positive signal for chemokine mRNA was observed both within the epidermis and inflammatory cells (macrophages, eosinophils, and T cells) of the subepidermis in AD skin lesions. Within the subepithelium acute and chronic skin lesions exhibited a significant increase in the numbers of eotaxin and MCP-4 mRNA-positive cells compared with uninvolved skin (P <.01), whereas the numbers of eotaxin and MCP-4 mRNA-positive cells were significantly higher in chronic AD compared with acute AD skin lesions (P <.005, P <.001, respectively). Correlations were observed between the expression of eotaxin and MCP-4 mRNA and the presence of eosinophils and macrophages, respectively, in AD lesions (r(2) = 0.84, r(2) = 0.94). CONCLUSION: There is an increased expression of eotaxin and MCP-4 in acute and chronic lesions, suggesting that these chemotactic factors play a major role in the pathophysiologic mechanisms of AD.     

Involvement of macrophage chemotactic protein-1 and interleukin-1beta during inflammatory but not basic fibroblast growth factor-dependent neovascularization in the mouse cornea

Corneal neovascularization develops in several pathologic conditions, but its underlying mechanisms remain elusive. We used a mouse inflammatory corneal model (corneas cauterized with silver nitrate) and assessed the role of monocyte/macrophage-attracting factors, macrophage chemotactic protein-1 (MCP-1), and a proinflammatory cytokine, IL-1beta, on macrophage recruitment and neovascularization. Both MCP-1, IL-1beta protein, and mRNA levels increased markedly 12 hours after the chemical cauterization. In situ hybridization showed that MCP-1 was located in corneal epithelial cells, and IL-1beta was located in corneal epithelial cells and infiltrating inflammatory cells. In addition, double staining of corneas with antibodies specific for monocytes/macrophages and IL-1beta revealed that IL-1beta was found in infiltrating monocytes/macrophages at Day 2 after cauterization. Both IL-1beta and MCP-1 induced neovascularization in a rat cornea model, and the cauterization-induced corneal neovascularization was partially inhibited by subconjunctival injection of anti-IL-1beta or anti-MCP-1. Coadministration of two antibodies inhibited corneal neovascularization slightly more than that by the administration of each. In contrast, administration of the anti-MCP-1 or anti-IL-1beta showed minimal inhibition of basic fibroblast growth factor-driven corneal neovascularization by mouse cornea assay. Cauterized corneas treated with anti-MCP-1 antibody had significantly fewer monocytes/macrophages than control. These results indicate the existence of distinct monocyte/macrophage-involved angiogenic pathways in mouse cornea, in which MCP-1 released from corneal epithelial cells attracts monocytes/macrophages into the cornea, where they release IL-1beta leading to inflammatory neovascularization. In addition, the IL-1beta and MCP-1 released from the corneal epithelial cells may directly induce corneal neovascularization.     

Expression of interleukin-6 and monocyte chemoattractant protein-1 by peritoneal sub-mesothelial cells during abdominal operations

Cytokines and chemokines including interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) are secreted in response to major abdominal operations. The aim of this study was to identify the peritoneal cells that produce IL-6 and MCP-1. Samples of peritoneal tissue were taken from patients at the beginning and end of major abdominal operations. The samples were incubated in culture medium on microtitre plates for 5 h. The concentrations of IL-6 and MCP-1 were measured in culture supernatants by enzyme-linked immunosorbent assay (ELISA). In paraffin sections, cells that expressed IL-6 or MCP-1 were identified by combined in situ hybridization and immunohistochemistry. Antibodies against CD68, CD34, actin, and calretinin were included in these experiments. The median production of IL-6 increased significantly from 6256 pg/ml at the start of the operation to 20,000 pg/ml at the end. Production of MCP-1 rose from 7700 pg/ml to 11,820 pg/ml. IL-6 mRNA was mainly confined to endothelial cells. MCP-1 was expressed by a broader range of cells, consisting of actin-positive smooth muscle cells and endothelial cells, fibroblast-like cells, as well as occasional macrophages and mesothelial cells. Peritoneal endothelial cells contribute to the transient increase in concentrations of IL-6 in the circulation after surgical trauma. Recruitment of monocytes to the site of the trauma seems to be mainly effected by actin-positive smooth muscle cells and endothelial cells.     

Cysteinyl leukotrienes induce monocyte chemoattractant protein 1 in human monocytes/macrophages

BACKGROUND: Monocytes/macrophages have a cysteinyl leukotriene 1 (CysLT1) receptor, but its function is poorly understood. Objective To elucidate the biological function of the CysLT1 receptor of human monocytes/macrophages. METHODS: We examined the production of TNF-alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, monocyte chemoattractant protein 1 (MCP-1), macrophage colony-stimulating factor (M-CSF), and eotaxin induced by CysLTs (leukotriene (LT)C4, -D4, and -E4) in THP-1 cells, a human monocytic leukaemia cell line, and peripheral blood CD14+ monocytes/macrophages. Moreover, we examined the effect of CysLTs on the expression of beta-chemokine receptor 2B (CCR2B) as the receptor of MCP-1 by Western blot analysis. RESULTS: ELISA revealed that CysLTs induced MCP-1 in THP-1 cells and peripheral blood CD14+ monocytes/macrophages, but not other cytokines. PCR demonstrated that CysLTs increased MCP-1 mRNA expression in THP-1 cells, and Western blotting showed that CysLTs increased the expression of CCR2B in THP-1 cells. Moreover, we demonstrated that pranlukast, a CysLT1 receptor antagonist, blocked MCP-1 production by CysLTs in THP-1 cells almost completely, and partially inhibited MCP-1 release by CysLTs in peripheral blood CD14+ monocytes/macrophages and CCR2B expression by CysLTs in THP-1 cells. CONCLUSION: CysLTs induce MCP-1 and increase CCR2B expression in human monocytes/macrophages.     

Progression of autoimmune damage in primary biliary cirrhosis: an immunohistochemical study

Aberrant MHC Class II antigen expression and the nature of the infiltrating lymphoid cells were studied by immunohistochemical techniques in liver biopsies from 37 patients with Primary biliary cirrhosis (PBC) (11 histological stage I, 13 stage II-III, 13 stage IV) and 15 patients with chronic non autoimmune liver disease. Bile duct epithelial cells expressed HLA-DR, DP and DQ antigens in biopsies from patients with early (Stage I) PBC and less frequently in the late cirrhotic phases of the disease (Stage IV); these observations support the hypothesis that induction of Class II antigens on epithelial cells may be involved in initiating autoimmune responses towards bile duct components. The presence of cytotoxic/suppressor T cells around the bile ducts in Stage I suggests a role for cell mediated destruction of the ducts at this early stage. The nature of the chronic inflammatory cell infiltrate in the portal tracts, periportal areas and lobular parenchyma does not establish the mechanism(s) involved in disease progression. However, the lack of Class II antigen expression on hepatocytes is compatible with the hypothesis that hepatocellular damage is non-specific and may be secondary to the initial bile duct injury.     

Liver disease in rhesus monkeys infected with simian immunodeficiency virus.

Rhesus monkeys infected with simian immunodeficiency virus (SIV) develop a syndrome very similar to patients with acquired immune deficiency (AIDS), including liver disease. This prospective study was undertaken to define the pathology, course, and pathogenesis of liver disease in 20 rhesus monkeys (Macaca mulatta) after intravenous inoculation with the standardized isolate SIV/DeltaB670. Tissue samples from liver and gallbladder between 2 and 24 weeks after inoculation were examined histologically and immunohistochemically for SIV gag protein p26, and by in situ hybridization with an SIV riboprobe. Histologically there was infiltration of portal tracts and around hepatic veins and venules by mononuclear inflammatory cells, focal bile duct damage, proliferation of bile ductules, and focal lobular inflammation as early as 2 weeks after infection. The severity and extent of these lesions were graded semiquantitatively and showed that bile duct damage and hepatic venulitis were the most significant changes. Simian immunodeficiency virus gag protein p26 and SIV RNA were detected in scattered mononuclear cells in portal tracts and sinusoids, but not in hepatocytes or bile duct epithelial cells. The data indicate that the liver is involved early during the course of SIV infection, followed by persistent changes until the terminal stage of the disease. Our findings suggest that the liver damage in SIV-infected rhesus monkeys is similar to the changes observed previously in AIDS patients.     

Expression of interleukin-8 and monocyte chemotactic protein-1 in adenomyosis

BACKGROUND: To clarify the inflammatory nature of adenomyosis, we aimed to investigate the expression of interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) by immunohistochemistry to determine their putative role in pathophysiology of adenomyosis. METHODS: Adenomyosis samples, with their eutopic endometrium, were collected from 30 women undergoing hysterectomy. Endometrium from 27 women without adenomyosis were also collected as a control group. Samples were grouped according to the menstrual cycle phase and examined by immunohistochemistry for IL-8 and MCP-1. RESULTS: In normal endometrium, secretory phase samples expressed higher levels of epithelial IL-8 than in proliferative phase samples (P = 0.01), and we observed a trend for an increased epithelial MCP-1 expression in the secretory phase samples compared with the proliferative phase samples (P = 0.07). Endometrial samples of women with adenomyosis did not show the same cyclic variation. In the secretory phase, eutopic endometrium of women with adenomyosis expressed lower levels of epithelial IL-8 and MCP-1 compared with normal endometrium (P < 0.05). The expression of epithelial IL-8 and MCP-1 was higher in the adenomyosis foci than the eutopic endometrium (P < 0.05). CONCLUSIONS: These findings may indicate that an intrinsic abnormality of inflammatory response may be present in eutopic endometrium of women with adenomyosis, and IL-8 and MCP-1 may contribute to the pathophysiology of adenomyosis.     

Increased expression of monocyte chemotactic protein-1 in the endometrium of women with endometriosis.

The pathogenesis of endometriosis, a disease widely believed to arise from an aberrant growth of endometrial tissue outside the uterus, is still unclear. We have previously observed that cytokine-stimulated endometrial cells of women with endometriosis secrete in vitro increased amounts of monocyte chemotactic protein-1 (MCP-1). This factor may be important in the recruitment and activation of peritoneal macrophages observed in endometriosis patients. The present study reports that, in the presence of the disease, such an up-regulation of MCP-1 expression arises in vivo and can be encountered in situ in the intrauterine endometrium. In women with endometriosis, MCP-1 expression was elevated in endometrial glands, both at the level of the protein (immunohistochemistry) and the mRNA (in situ hybridization). This was observed throughout the menstrual cycle and varied according to the stage of the disease. These findings strongly argue in favor of the presence of pathophysiological changes in the eutopic endometrium of patients with endometriosis and make plausible MCP-1 as a key effector cell mediator involved in the pathogenesis of the disease.     

Interleukin-12-induced adhesion molecule expression in murine liver.

Systemically administered interleukin (IL)-12 causes liver inflammation in mice characterized by Kupffer cell proliferation and hypertrophy, hepatocyte necrosis, and multifocal accumulations of leukocytes in the hepatic parenchyma and around portal tracts and central veins. We have used both immunohistochemical staining and radiolabeled antibody quantitation to examine adhesion molecule expression in the livers of mice dosed daily with murine IL-12. Cells infiltrating livers of IL-12-treated mice were primarily mononuclear leukocytes expressing LFA-1, VLA-4, MAC-1, and CD18 adhesion molecules but little L-selectin. Kupffer cells constitutively expressed LFA-1 and smaller amounts of MAC-1, and high levels of ICAM-1 were constitutively expressed by liver sinusoidal lining cells, portal tract, and central vein endothelia. With IL-12 treatment, existing ICAM-1 expression was up-regulated and de novo expression occurred along bile duct epithelia. VCAM-1 levels were dramatically increased, with induced expression occurring along portal tract and central vein endothelia and scattered bile duct epithelial cells and in aggregations of cells in perivascular areas and the liver parenchyma. Although constitutive expression of E- and P-selectin was negligible, Il-12 induced a moderate rise in E-selectin levels. These increases in adhesion molecule expression may have implications for the therapeutic use of IL-12, especially in patients with liver disease or autoimmune conditions where augmented adhesion molecule expression may be critical to disease pathogenesis.     

Graft-versus-Host Disease in the Rat: Cellular Changes and Major Histocompatibility Complex Antigen Expression in the Liver

Cellular changes in the liver were studied during an acute lethal graft-versus-host (GVH) disease in relation to the expression of major histocompatibility complex (MHC) antigens on different liver cells. Screening for MHC antigen expression revealed that control livers contained very few Ia+ cells: mainly cells in the portal tract interstitium and a small percentage of the Kupffer cells. The changes during an ongoing GVH reaction could be separated into those related to the sinusoid-associated cells, including the liver parenchyma, and those related to the portal-tract-associated cells, including periportal hepatocytes. In the sinusoids an increase in the number of Kupffer cells was seen, now all expressing Ia antigens. No damage to hepatocytes or other sinusoid-associated cells was observed. It is postulated that the increase in both number and Ia expression of the Kupffer cells is most probably due to an increased phagocytic uptake of blood-borne cellular debris and is not a result of extensive damage to hepatocytes. In the portal tracts expanding infiltrates were found composed of Ia+ T cells and macrophages (ratio 2:1). These infiltrates are probably due to a local accumulation of lymphocytes and macrophages as a result of an interaction of migrating donor-type alloreactive T cells with recipient type Ia+ cells present in the portal tract interstitium, which also interfered with normal recipient lymphocyte and macrophage traffic. Damage to portal-tract-associated cells was slight and confined to bile duct epithelial cells, which now expressed Ia antigens, and to periportal hepatocytes. In conclusion, these data do not indicate that damage to liver parenchyma plays a major role in the pathogenesis of an acute GVH reaction.