Spatial distribution of cell adhesion molecules on the peritoneal surface in the cecal perforation-induced peritonitis

For understanding the immunological functions of the peritoneum, spatial localization of integrins and their ligands was studied by immuno-SEM on the peritoneal surface of mice with cecal perforation-induced peritonitis. The cecal peritoneum 24 hr after perforation was stained with specific antibodies against LFA-1, Mac-1, VLA-4, ICAM-1, VCAM-1, and fibronectin diluted with cold University of Wisconsin (UW) solution in conjunction with immuno-gold labeling. The spatial localization of those cell adhesion molecules was detected by backscatter electron (BSE) imaging with field emission scanning electron microscope (FESEM). Numerous leukocytes with diverse surface ultrastructure were observed on the peritoneal surface by FESEM. Some leukocytes were in contact with mesothelial cells, and others adhered to the exposed underlying connective tissue. The BSE imaging showed the ubiquitous distribution of Mac-1 on all membrane domains of leukocytes, i.e., cell body, ruffles, and microvilli. In contrast, predominant expressions of LFA-1 and VLA-4 were discernible on ruffles/microvilli of some leukocytes. The mesothelial cells remaining in the inflamed area expressed both ICAM-1 and VCAM-1 on their microvilli. The fibronectin was detected on presumable collagen fibers and/or fibrin over the exposed smooth muscle layer as well as on fibrin extending between leukocyte aggregation. The spatial microlocalization of integrins was clarified on the leukocytes emigrated in peritonitis, and their ligands were detected on the inflamed peritoneum.     

Adhesion molecules and atherogenesis

Atherosclerosis is an inflammatory disease of the vessel wall characterized by monocyte infiltration in response to pro‐atherogenic factors such as oxidized lipids. Recently, the role of specific adhesion molecules in this process has been explored. The endothelium overlying atherosclerotic lesions expresses P‐selectin and the shoulder regions express vascular cell adhesion molecule‐1 (VCAM‐1) and intercellular adhesion molecule‐1 (ICAM‐1), which is also expressed on endothelium in regions not prone to plaque development. Serum levels of soluble P‐selectin, ICAM‐1 and VCAM‐1 are elevated in patients with angina pectoris or peripheral atherosclerotic disease. Reconstituted in vitro systems using monocytes on cytokine‐activated endothelial cells under shear flow suggested the involvement of P‐selectin, L‐selectin, VCAM‐1, its ligand, VLA‐4 integrin and CD18 integrins. Studies of monocyte adhesion in isolated perfused carotid arteries harvested from atherosclerotic (apoE?/?) mice show a predominant involvement of P‐selectin and its ligand P‐selectin glycoprotein‐1 (PSGL‐1) in rolling and of VLA‐4 and VCAM‐1 in firm adhesion. Consistent with these findings, apoE?/? mice that are also deficient for P‐selectin show significantly reduced atherosclerotic lesion sizes and are almost completely protected from neointimal growth after vascular injury. Milder effects are also seen in the low‐density lipoprotein (LDL) receptor deficient (LDLR?/?) mouse. In a high cholesterol/cholate model, a role of ICAM‐1 and CD18 integrins was also shown, but this awaits confirmation in more physiologic models. Transient blockade of the VLA‐4/VCAM‐1 adhesion pathway by antibodies or peptides in apoE?/? or LDLR?/? mice reduced monocyte and lipid accumulation in lesions. These data suggest that P‐selectin, PSGL‐1, VLA‐4 and VCAM‐1 are the most important adhesion molecules involved in monocyte recruitment to atherosclerotic lesions.     

Expression of adhesion molecules in allergic lung diseases

Endothelial adherence and migration of leukocytes into tissue is mediated by different sets of adhesion molecules. The expression of these sets might not only preselect the types of leukocytes that enter the inflammatory sites, but also activate these leukocytes, induce adherence to epithelial cells, and cause the release of cytokines. Atopic asthma, extrinsic allergic alveolitis, and sarcoidosis as examples of immunologic lung diseases were investigated for the expression of adhesion molecules. Bronchial biopsies in chronic obstructive lung disease (COPD) and resected lung tissue of juvenile emphysema were chosen for controls. Immunohistochemistry was done on sections from bronchial and transbronchial biopsies and on smears from bronchoalveolar lavage cells. In all three types of immune disorders, lymphocytes expressed the integrins alpha4/beta1 (VLA4) and ICAM3, whereas lymphocytes in COPD bronchitis and in emphysema controls were unreactive. Eosinophils in atopic asthma bronchitis in contrast to COPD bronchitis also expressed both VLA4 and ICAM3. The expression of VCAM1 on endothelial cells was only seen in atopic asthma and was related to disease activity. The expression of other adhesion molecules was nonspecific. Expression of VCAM1 on endothelial cells and its ligand VLA4 on lymphocytes and eosinophils seems to be a specific event in atopic asthma. Expression of VLA4 and ICAM3 on lymphocytes, however, might be a specific event in all three immune reactions.     

Corticosterone treatment of pregnant low dose endotoxin-treated rats: inhibition of the inflammatory response

PROBLEM: Can the endotoxin‐induced inflammatory response, underlying experimental pre‐eclampsia, in pregnant rats be inhibited by corticosterone?
METHOD OF STUDY: On day 10 of pregnancy, rats were implanted with pellets containing 25% corticosterone and 75% cholesterol (n=10) or with 100% cholesterol‐pellets (n=10). On day 14 of pregnancy, rats were infused with either endotoxin (1.0 μg/kg bw) or saline. Three days later, they were sacrificed. Cryostat kidney sections were immunohistologically stained for the presence of neutrophils (PMN) and monocytes (M?) and the expression of inflammation‐associated adhesion molecules.
RESULTS: In cholesterol‐treated rats, endotoxin significantly increased glomerular numbers of PMN and M?, glomerular expression of ICAM‐1 and VCAM‐1 and glomerular numbers of LFA‐1 and VLA‐4‐positive cells as compared with saline. Corticosterone treatment significantly inhibited glomerular infiltration of PMN, M? and LFA‐1 positive cells after endotoxin infusion. It did not affect glomerular ICAM‐1 or VCAM‐1 expression or numbers of VLA‐4 positive cells.
CONCLUSIONS: It is concluded that pre‐treatment with corticosterone inhibits the low dose endotoxin‐induced glomerular inflammatory reaction in pregnant rats, most likely by inhibiting LFA‐1 expression, thereby decreasing the adhesiveness of inflammatory cells for activated endothelial cells.     

Glatiramer acetate attenuates the pro‐migratory profile of adhesion molecules on various immune cell subsets in multiple sclerosis

An altered expression pattern of adhesion molecules (AM) on the surface of immune cells is a premise for their extravasation into the central nervous system (CNS) and the formation of acute brain lesions in multiple sclerosis (MS). We evaluated the impact of glatiramer acetate (GA) on cell‐bound and soluble AM in the peripheral blood of patients with relapsing–remitting MS (RRMS). Fifteen patients treated de novo with GA were studied on four occasions over a period of 12 months. Surface levels of intracellular cell adhesion molecule (ICAM)‐1, ICAM‐3, lymphocyte function‐associated antigen (LFA)‐1 and very late activation antigen (VLA)‐4 were assessed in T cells (CD3⁺CD8⁺, CD3⁺CD4⁺), B cells, natural killer (NK) cells, natural killer T cells (NK T) and monocytes by five‐colour flow cytometry. Soluble E‐selectin, ICAM‐1, ICAM‐3, platelet endothelial cell adhesion molecule (PECAM)‐1, P‐selectin and vascular cell adhesion molecule (VCAM)‐1 were determined with a fluorescent bead‐based immunoassay. The pro‐migratory pattern in RRMS was verified by comparison with healthy controls and was characterized by up‐regulation of LFA‐1 (CD3⁺CD4⁺ T cells, B cells), VLA‐4 (CD3⁺CD8⁺ T cells, NK cells), ICAM‐1 (B cells) and ICAM‐3 (NK cells). Effects of GA treatment were most pronounced after 6 months and included attenuated levels of LFA‐1 (CD3⁺CD4⁺) and VLA‐4 (CD3⁺CD4⁺, CD3⁺CD8⁺, NK, NK T, monocytes). Further effects included lowering of ICAM‐1 and ICAM‐3 levels in almost all immune cell subsets. Soluble AM levels in RRMS did not differ from healthy controls and remained unaltered after GA treatment. The deregulated pro‐migratory expression profile of cell‐bound AM is altered by GA treatment. While this alteration may contribute to the beneficial action of the drug, the protracted development and unselective changes indicate more secondary immune regulatory phenomena related to these effects.     

Abdominal peritoneum as a defense organ: Analysis of ICAM‐1 expression in the LPS‐stimulated rat

To investigate the immune environment of the peritoneal cavity, ICAM‐1 (intercellular adhesion molecule) expression on the apical surface of the hepatic peritoneum of LPS (lipopolysaccharide) stimulated rats was anlayzed ultrastructurally and chronologically with immnunoTEM&SEM. ICAM‐1 expression was restricted to the side of microvilli of the mesothelial cells. Microvilli demonstrated bulbous tips and included fuzzy coats and strands. Bulbous tips sometimes expressed the antigen, but fuzzy coats and strands did not. Intervillar cell surfaces lacked its expression. Although ICAM‐1 expression increased eightfold 24 hr after stimulation, the selective expression remained unchanged. These results suggest that microvilli are closely associated with cell migration in the peritoneal cavity through adhesion molecules that establish a road for migration. Clin. Anat. 12:20–26, 1999. © 1999 Wiley‐Liss, Inc.     

The use of the soluble adhesion molecules sE‐selectin,sICAM‐1, sVCAM‐1, sPECAM‐1 and their ligands CD11a and CD49d as diagnostic and prognostic biomarkers in septic and critically ill non‐septic ICU patients

Endothelial activation is pivotal in the development and escalation of sepsis. Central to endothelial activation is the endothelial up‐regulation of cellular adhesion molecules (CAMs) including E‐selectin, ICAM‐1, VCAM‐1, and PECAM‐1. Shed CAMs are also found in circulating soluble forms (sCAMs). We investigated whether sCAMs can be used as biomarkers for the differentiation between septic and non‐septic patients. Furthermore, we investigated lymphocyte and monocyte expression of LFA‐1 (CD11a/CD18) and VLA‐4 (CD49d/CD29) ligands for ICAM‐1 and VCAM‐1, respectively. Twenty‐one septic and 15 critically ill non‐septic patients were included. All patients had an APACHE II score above 13 at ICU admission. Fifteen healthy volunteers served as controls. Flow cytometry was used to estimate levels of sE‐selectin, sICAM‐1, sVCAM‐1, sPECAM‐1, and the cellular expression of CD11a and CD49d. Levels of sE‐selectin, sICAM‐1 and sPECAM‐1 were higher in the septic patients compared with the non‐septic patients and controls at admission and during the observation period. Lymphocyte and monocyte expression of CD11a and CD49d was suppressed or unaltered in the septic patients compared with the non‐septic patients and controls. Levels of sE‐selectin, sICAM‐1, and sPECAM‐1 were able to discriminate between septic and non‐septic patients, indicating that sCAMs may be potential diagnostic biomarkers of sepsis.     

重症烧伤休克大鼠白细胞表面beta-2整合素的表达

目的 :阐明烧伤休克时 beta-2整合素与白细胞 -内皮细胞粘附间的关系。方法 :将 16只 SD大鼠随机均分为对照组和烧伤休克组。应用流式细胞技术检测中性粒细胞及单细胞表面 beta-2整合素CD11a( LFA-1)和 CD11b( Mac-1)的表达量变化 ,同时比较观察二组动物肠系膜微循环中微静脉内白细胞与内皮细胞粘附数量变化。结果 :二组自身对照 (烫伤前与烫伤后 3 h或开腹前与开腹后 3 h)及相互对比结果显示 ,中性粒细胞及单核细胞表面 CD11a表达量均无显著差异 ( P>0 .0 5 ) ;在烧伤组 ,单核细胞 CD11b有显著降低( P<0 .0 5 ) ,而中性粒细胞 CD11b有显著升高 ( P<0 .0 5 )。微循环观察结果显示 ,休克组动物烫伤后随时程延长附壁滚动及紧密粘附的白细胞数量明显增多 ,而对照组则无明显变化。结论 :烧伤休克状态下 ,白细胞表面 CD11a数量无显著变化 ,而 CD11b数量则有所改变。白细胞 -内皮细胞粘附力的增强可能有 beta-2整合素功能活性上调参与。     

Functional relevance during lymphocyte migration and cellular localization of activated β1 integrins

The state of integrin activation can be assessed by monoclonal antibodies (mAb) that selectively recognize integrins in their active form. We demonstrate herein that the expression of the epitope recognized by mAb HUTS-21 is induced on T lymphoblasts upon binding of soluble vascular cell adhesion molecule (VCAM)-1 and an 80-kDa tryptic fragment of fibronectin (FN80) to the β1 integrins very late activation antigen (VLA)-4 and VLA-5, and that this effect is dependent on ligand concentration and is specific for β1 integrins. On T lymphoblasts adhering to immobilized fibronectin, the HUTS-21 epitope localized exclusively to sites of integrin binding to fibronectin. These results indicate that mAb HUTS-21 recognizes a ligand-induced binding site (LIBS) on the common β1 subunit of VLA proteins. Engagement of β1 integrins through this LIBS epitope inhibited T lym-phoblast movement on fibronectin, as determined by quantitative time-lapse video microscopy studies. Furthermore, the HUTS-21 mAb also prevented T lymphoblast-directed migration through gradients of substratum-immobilized β1 integrin ligands such as fibronectin or VCAM-1, whereas it did not affect migration on intercellular adhesion molecule (ICAM)-1. This anti-LIBS mAb stimulated cell adhesion through postreceptor events, without affecting receptor affinity for ligand, and appears to interfere with cell migration by a mechanism distinct from that of other anti-β1 activating antibodies.     

Cathepsin X cleaves the β2 cytoplasmic tail of LFA‐1 inducing the intermediate affinity form of LFA‐1 and α‐actinin‐1 binding

The motility of T cells depends on the dynamic spatial regulation of integrin‐mediated adhesion and de‐adhesion. Cathepsin X, a cysteine protease, has been shown to regulate T‐cell migration by interaction with lymphocyte function associated antigen‐1 (LFA‐1). LFA‐1 adhesion to the ICAM‐1 is controlled by the association of actin‐binding proteins with the cytoplasmic tail of the β₂ chain of LFA‐1. Cleavage by cathepsin X of the amino acid residues S⁷⁶⁹, E⁷⁶⁸ and A⁷⁶⁷ from the C‐terminal of the β₂ cytoplasmic tail of LFA‐1 is shown to promote binding of the actin‐binding protein α‐actinin‐1. Furthermore, cathepsin X overexpression reduced LFA‐1 clustering and induced an intermediate affinity LFA‐1 conformation that is known to associate with α‐actinin‐1. Increased levels of intermediate affinity LFA‐1 resulted in augmented cell spreading due to reduced attachment of T cells to the ICAM‐1‐coated surface. Gradual cleavage of LFA‐1 by cathepsin X enables the transition between intermediate and high affinity LFA‐1, an event that is crucial for effective T‐cell migration.     

Blood Lymphocytes,Monocytes and NK Cells Modulate Their Expression of CD44, ICAM‐1, LFA‐1 and MHC Class II After Arrival Into Lymphoid Organs

Adhesion molecules expressed on surface membranes of lymphocytes and other leukocytes enable their entry into the lymphoid and other tissues. However, little is known about molecules that govern the transit of leukocytes through the parenchyma of lymphoid organs proper. We show that in comparison to blood leukocytes, the corresponding cells isolated from lymphoid organs, i.e., lymph nodes and spleen, have a significantly augmented expression of certain surface molecules. The helper and cytotoxic subsets of T cells, as well as B cells, display the increased expression of CD44, ICAM‐1 and LFA‐1, whereas B cells additionally show the augmented expression of MHC class II. In comparison with blood monocytes, splenic monocytes show the increased expression of ICAM‐1 and MHC class II molecules. When compared with blood NK cells, splenic NK cells only show the increased expression of ICAM‐1. The molecules, which we show to be up regulated upon the entry of leukocytes into lymphoid organs, could be involved in their retention within the tissue via cell–cell or cell‐extracellular matrix interactions and in control of their transit through lymphoid tissues.     

Expression of adhesion molecules relevant to leukocyte migration on the microvilli of liver peritoneal mesothelial cells

To help assess the immunological functions of the liver peritoneum, expression and 3D-microlocalization of adhesion molecules were studied by immuno-SEM and -TEM. The peritoneal tissues of the liver obtained from lipopolysaccharide (LPS, 1.5 microg/g BW for 24 hr)-stimulated (n = 18 including nine controls) and non-stimulated mice (n = 6 including three controls) were analyzed by immunolabeling with 15 nm gold particle single-labeling analysis of ICAM-1, ICAM-2, VCAM-1, MAdCAM-1, PECAM-1, ELAM-1, and CD105 expression. In addition, 10 and 20 nm gold particle double-labeling analysis of ICAM-1 and VCAM-1 was carried out with conventional TEM and BSE (backscatter electron) imaging. Gold particles detected in the peritoneal mesothelial cells were quantified using a computer analyzer, LUZEX III. Only ICAM-1 in non-stimulated mice and both ICAM-1 and VCAM-1 in LPS-stimulated mice were expressed on the mesothelium, but no other adhesion molecules were detected in either condition. Expression of ICAM-1 was consistently about four times greater than that of VCAM-1. Each adhesion molecule was restricted to the microvilli. ICAM-1 was expressed on all microvilli and tended to form clusters of three or four molecules. On the other hand, about 24% of the microvilli expressed VCAM-1 and less clustering was seen. Double-labeling techniques disclosed that VCAM-1 and ICAM-1 were rarely closely associated, usually spaced by about 40 nm. These results suggest that microvilli of the mesothelial cell play a significant role in leukocyte migration in the peritoneal cavity, by providing the important substrates for adhesion, ICAM-1 and VCAM-1.     

Feasibility of mesothelial transplantation during experimental peritoneal dialysis and peritonitis

The mesothelial cell layer lining the peritoneum orchestrates peritoneal homeostasis. Continuous exposure to peritoneal dialysis fluids and episodes of peritonitis may damage the monolayer irreversibly, eventually leading to adhesion formation and fibrosis/sclerosis of the peritoneum. Autologous mesothelial cell transplantation is thought to be one of the options to reduce dysfunction of the peritoneal membrane. In this article we will review the mesothelial cell transplantation experiments performed in the field of peritoneal dialysis and peritonitis. In addition we will focus on the trouble shooting using cultured autologous mesothelial cells for transplantation.     

Role of Kaposi's sarcoma cells in recruitment of circulating leukocytes: implications in pathogenesis

OBJECTIVE: We sought to identify and characterize mechanisms of interaction between Kaposi's sarcoma cells and circulating leukocytes leading to leukocyte migration into the lesion. STUDY DESIGN/METHODS: By using static and dynamic adhesion models, we measured the ability of late-stage KSY1 cells to support adhesion and transmigration of peripheral blood lymphocytes (PBL). RESULTS: We showed that resting as well as TNF-alpha- or PMA-activated KSY1 cells supported adhesion and transmigration of PBL with a higher efficiency compared with normal endothelial cells. The LFA1/ICAM1 pathway was totally involved in PBL adhesion to resting or TNF-alpha-activated KSY1 cells and partially responsible for adhesion to PMA-activated KSY1 cells. No inhibition of adhesion was observed by blockage of the VLA4 pathway. Under flow conditions, PBL/KSY1 cell interaction was totally dependent on L-selectin. CONCLUSION: Our data indicate that KS cells mimic an endothelium-like structure by regulating extravasation of lymphocytes into lesions.     

Stimulation of naïve T-cell adhesion and immunological synapse formation by chemokine-dependent and -independent mechanisms

Chemokines adsorbed to the cell surface play an important role in the initial interactions of T cells with endothelial cells, and may also have a role in T‐cell interactions with dendritic cells. Therefore, we examined the effect of surface‐adsorbed chemokines on the interaction of naïve murine splenic T cells with supported bilayers containing intercellular adhesion molecule (ICAM)‐1, or with bone marrow‐derived cultured dendritic cells in the presence and absence of relevant MHC–peptide complexes. Naïve T cells formed immunological synapses, defined as a ring of lymphocyte function associated (LFA)‐1–ICAM‐1 interactions surrounding a central cluster of MHC–peptide complexes, on supported planar bilayers containing ICAM‐1 and relevant MHC–peptide complexes. Chemokines stimulated an increase in the percentage of naïve cells that adhered to ICAM‐1, but did not increase the average number of LFA‐1–ICAM‐1 interactions in the contact area. In contrast, relevant MHC–peptide complexes resulted in a small increase in the proportion of interacting T cells, but stimulated an 8‐fold increase in the number of LFA‐1–ICAM‐1 interactions in each contact formed. Naïve T cells displayed a significant basal adhesion to bone marrow dendritic cells that was further increased when relevant chemokines were adsorbed to the dendritic cell surface. However, basal and antigen‐stimulated T‐cell adhesion to dendritic cells was not sensitive to pertussis toxin. Thus, there are chemokine‐independent mechanisms that initiate adhesion between T cells and dendritic cells.     

Interleukin-15 induces adhesion receptor redistribution in T lymphocytes

Chemotactic factors such as cytokines and chemokines direct the migration of leukocytes into inflammatory sites. Chemokines play a role regulating both the expression and adhesive properties of leukocyte integrins. We have recently described an additional function of chemokines in the induction of cell polarization and adhesion receptor redistribution during the initial step of leukocyte locomotion. We herein report that interleukin (IL)-15, a newly described cytokine with chemotactic properties, is able to induce uropod formation on T lymphoblasts to which intercellular adhesion molecule (ICAM)-3, a leukocyte-restricted counter-receptor for the lymphocyte function-associated antigen (LFA)-1 integrin, is redistributed. Other adhesion molecules, such as ICAM-1, ICAM-2, CD43 and CD44, also redistributed to the uropod, although in a lower proportion of the cells. The induction of uropod formation by IL-15 was observed on T lymphoblasts adhering to the integrin ligands fibronectin, vascular cell adhesion molecule (VCAM)-1 and ICAM-1, but not to bovine serum albumin or poly-L -lysine. The effect of IL-15 was dose dependent and specifically inhibited by a monoclonal antibody (mAb) against this cytokine. Blocking experiments with anti-IL-2 receptor β chain mAb showed an inhibitory effect on IL-15-mediated redistribution of ICAM-3, whereas no effect was observed in the presence of anti-IL-2 receptor α chain mAb. The uropod induced by IL-15 is enriched in many different adhesion receptors and, being well exposed to the external milieu, is likely to modulate the adhesive properties of lymphocytes.     

人体腹膜壁层间皮细胞微绒毛的超微结构

本文应用扫描电镜、透射电镜和冷冻复型技术对16例人体腹膜壁层间皮进行了观察。结果表明腹膜间皮细胞表面均有微绒毛,但不同部位微绒毛的长短、疏密和排列的方式不同。有的绒毛具有一些特殊形态:(1) 鼓槌状微绒毛;(2) 分叉状微绒毛;(3) 一根微绒毛主干上有多根次级微绒毛;(4) 微绒毛内含有吞饮小泡;(5) 微绒毛根部或其边缘有吞饮小泡开口。     

High interindividual variability in the CD4/CD8 T cell ratio and natalizumab concentration levels in the cerebrospinal fluid of patients with multiple sclerosis

Strongly decreased leucocyte counts and a reduced CD4/CD8 T cell ratio in the cerebrospinal fluid (CSF) of natalizumab (NZB)‐treated multiple sclerosis (MS) patients may have implications on central nervous (CNS) immune surveillance. With regard to NZB‐associated progressive multi‐focal leucoencephalopathy, we aimed at delineating a relationship between free NZB, cell‐bound NZB, adhesion molecule (AM) expression and the treatment‐associated shift in the CSF T cell ratio. Peripheral blood (PB) and CSF T cells from 15 NZB‐treated MS patients, and CSF T cells from 10 patients with non‐inflammatory neurological diseases and five newly diagnosed MS patients were studied. Intercellular adhesion molecule‐1 (ICAM‐1), leucocyte function antigen‐1 (LFA‐1), very late activation antigen‐4 (VLA‐4), NZB saturation levels, and T cell ratios were analysed by flow cytometry. NZB concentrations were measured by enzyme‐linked immunosorbent assay (ELISA). Lower NZB saturation levels (P < 0·02) and a higher surface expression of ICAM‐1 and LFA‐1 (P < 0·001) were observed on CSF CD8 T cells. CSF T cell ratios (0·3–2·1) and NZB concentrations (0·01–0·42 µg/ml) showed a pronounced interindividual variance. A correlation between free NZB, cell‐bound NZB or AM expression levels and the CSF T cell ratio was not found. Extremely low NZB concentrations and a normalized CSF T cell ratio were observed in one case. The differential NZB saturation and AM expression of CSF CD8 T cells may contribute to their relative enrichment in the CSF. The reduced CSF T cell ratio appeared sensitive to steady‐state NZB levels, as normalization occurred quickly. The latter may be important concerning a fast reconstitution of CNS immune surveillance.     

Correlation of DTI metrics in the wall and cavity of brain abscess with histology and immunohistochemistry

Diffusion tensor imaging (DTI) was performed in eight patients with brain abscess (BA). The aim of this study was to see the difference in the relationship between intercellular cell adhesion molecule‐1 (ICAM‐1) and lymphocyte function‐associated antigen‐1 (LFA‐1) expression and DTI metrics measured in vivo in the wall and cavity of BA and its possible explanation vis‐à‐vis histology and immunohistochemistry. Neuroinflammatory molecules (NMs) were quantified from BA cavity aspirate of the patients and quantitative immunohistochemical analysis was performed for ICAM‐1 and LFA‐1 in the BA wall, showing maximal positive staining and correlated with DTI metrics. The fractional anisotropy (FA) significantly increased while mean diffusivity and spherical anisotropy significantly decreased in the BA wall compared to the BA cavity. In the BA wall, FA and linear anisotropy (CL) showed a significant positive correlation with ICAM‐1 and LFA‐1 expression whereas FA and planar anisotropy positively correlated with NMs quantified from aspirated pus respectively. Higher FA values in the BA wall compared to BA cavity, even when ICAM‐1 and LFA‐1 were expressed only in the macrophages and not in the collagen fibers, suggests that a combination of both concentric layers of collagen fibers as well as neutrophils and macrophages provide structural orientation and are responsible for increased FA. In the BA wall, increased CL was found compared to the cavity, indicating the presence of concentrically laid collagen fibers responsible for the diffusion of water molecules in the direction parallel to the collagen fibers. We conclude that in the BA, different mechanisms are operative for the changes in the DTI metrics in the wall and cavity; these conclusions are validated by histology and immunohistochemistry. Copyright © 2009 John Wiley & Sons, Ltd.     

Mesothelial cell sheets cultured on fibrin gel prevent adhesion formation in an intestinal hernia model

In the present study, we examined a novel technique to prevent adhesion formation in a rat intestinal hernia model with mesothelial cell sheets cultured on fibrin gel. Mesothelial cells were obtained from isologous rats by enzymatic disaggregation of mesentery and cultured on fibrin gel. Electron microscopy revealed that these cultured cells form contiguous monolayer cell sheets with well-developed microvilli. These tissue-engineered constructs were grafted in vivo to an intestinal hernia model that results in regular surgical adhesions without treatment. Five days postgrafting, rats were sacrificed. Adhesion formation was not observed in rats grafted with the constructs, whereas severe adhesions were observed in all control rats. Constructs seeded with mesothelial cells isolated from EGFP-transgenic rats clearly revealed that grafted mesothelial cells remained at the host tissue site even after fibrin scaffold degradation. These cells developed more abundant microvilli in vivo than those in vitro. These results show that cultured mesothelial cell sheets are effective in preventing adhesion formation and should reduce postoperative complications caused by adhesion formation.