Biomedical subjects

Z Szekanecz

Publications and source records attributed to Z Szekanecz.

12 recordsLinked to original sources

PubMed1995

Increased synovial expression of the adhesion molecules CD66a, CD66b, and CD31 in rheumatoid and osteoarthritis.

Leukocyte-endothelial interaction mediated by adhesion molecules may play a role in the ingress of inflammatory cells into the rheumatoid (RA) synovial tissue (ST). A number of these molecules have been shown to be up-regulated in the inflamed compared to normal ST. We studied the distribution of two members of the CD66 carcinoembryonic antigen adhesion molecule family, as well as that of CD31, an antigen structurally related to CD66, on various cell types in the RA compared to osteoarthritic (OA) and normal ST. Immunoperoxidase histochemistry was carried out using monoclonal antibodies to CD66a, CD66b, and CD31. This study was performed on ST from 10 patients with RA, 10 with OA, and 4 normal individuals. CD66a, and CD66b were expressed on RA and OA ST myeloid cells but not on normal ST lining cells and interstitial macrophages, suggesting that these antigens may be specific markers of diseased compared to normal ST macrophages (P < 0.05). CD31 was present on more RA and OA than on normal ST macrophages. Also, CD31 was present on most RA, OA, and normal ST endothelial cells. Our results indicate that the expression of CD66a, CD66b, and CD31, members of the immunoglobulin superfamily of adhesion receptors, is up-regulated on cells of myeloid origin in the inflamed compared to normal ST. These results suggest that the CD66 antigens and CD31 may be involved in the adhesive events in the inflamed synovium.

Antigens, CD↗

PubMed1995

Increased synovial expression of transforming growth factor (TGF)-beta receptor endoglin and TGF-beta 1 in rheumatoid arthritis: possible interactions in the pathogenesis of the disease.

The ingress of inflammatory cells into the rheumatoid (RA) synovial tissue (ST) plays a role in the pathogenesis of this disease. Transforming growth factor beta (TGF-beta) may play a role in this process. We have investigated the distribution of endoglin, a newly described receptor for TGF-beta 1 and -beta 3, in RA compared to osteoarthritis (OA) or normal ST. Immunohistochemical analysis was carried out using an anti-TGF-beta 1 monoclonal antibody (mAb) as well as 10 mAbs raised against various epitopes of endoglin. This study was performed on ST from 10 patients with RA, 10 with OA, and 4 normal individuals. TGF-beta 1 expression was significantly up-regulated on RA compared to OA and normal ST lining cells, interstitial macrophages, and endothelial cells (P < 0.05). All anti-endoglin mAbs uniformly reacted with endothelial cells in RA, OA, and normal STs. However, 3 out of 10 anti-endoglin mAbs reacted with significantly more RA versus normal ST lining cells (P < 0.05), as well as RA compared to OA and normal macrophages (P < 0.05). There was a positive correlation between TGF-beta 1 and endoglin reactivity on the synovial lining layer and subsynovial macrophages (P < 0.05). These results indicate that TGF-beta 1 and certain epitopes of endoglin, a TGF-beta 1 and -beta 3 receptor, are up-regulated on myeloid elements in RA compared to normal ST. Endoglin is also present on ST endothelia, and its expression may also be increased on OA compared to normal ST lining cells. These findings implicate endoglin in the pathogenesis of RA.

Antibodies, Monoclonal↗

PubMed1994

Differential distribution of intercellular adhesion molecules (ICAM-1, ICAM-2, and ICAM-3) and the MS-1 antigen in normal and diseased human synovia. Their possible pathogenetic and clinical significance in rheumatoid arthritis.

OBJECTIVE: Cellular adhesion and differentiation molecules (CAMs) may play a role in the recruitment and retention of inflammatory cells into rheumatoid arthritis synovial tissue (RA ST). In order to determine if certain CAMs are up-regulated in RA ST compared with normal ST, we studied the distribution of intercellular adhesion molecules (ICAMs) 1, 2, and 3 in ST. We also studied the MS-1 antigen since it is preferentially expressed on discontinuous endothelia, such as those found in RA ST; MS-1 is also expressed differentially upon cytokine activation of cells in vitro or in pathologic conditions in situ. Thus, we postulated a possible similarity between MS-1 and ICAM-1 expression in inflamed ST. METHODS: Immunohistochemical analysis was used to determine the distribution of ICAMs and MS-1 in ST from 10 patients with RA, 10 with osteoarthritis (OA), and 4 normal individuals. RESULTS: ICAM-1 expression was found on significantly more RA ST endothelial cells compared with normal cells, as well as on RA ST macrophages and lining cells. ICAM-2, also found on endothelial cells, showed no differential staining pattern. ICAM-3 was present on RA ST macrophages and lining cells as well as on some RA and OA endothelial cells. The MS-1 antigen was present on most RA and OA ST endothelia, lining cells, and macrophages. ICAM-1 expression and MS-1 expression in the lining layer were positively correlated in both RA and OA. CONCLUSION: ICAM-1, while found mainly on endothelial cells, is up-regulated on RA ST macrophages and lining cells, suggesting a role for these cells in the infiltration and tissue damage seen in the RA ST: ICAM-3, which is present mainly on normal resting leukocytes but not on normal endothelium, is expressed by some diseased ST leukocytes and endothelial cells. MS-1 is also found on the RA ST specialized, fenestrated endothelium, on macrophages, and in the lining layer. These results suggest that the differential expression of ICAMs and MS-1 in RA ST compared with normal ST might play a special role in the pathogenesis of RA.

Arthritis, Rheumatoid↗

PubMed1994

Human atherosclerotic abdominal aortic aneurysms produce interleukin (IL)-6 and interferon-gamma but not IL-2 and IL-4: the possible role for IL-6 and interferon-gamma in vascular inflammation.

Immunological mechanisms play an important role in the pathogenesis of atherosclerosis and atherosclerotic abdominal aortic aneurysms (AAA). Inflammatory leukocytes invade the vessel wall and produce cytokines which perpetuate the immune events underlying these diseases. Interleukin (IL)-1 beta, IL-8, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1, among others, may play a role in the generation by AAA. The aim of this study was to investigate the possible pathogenetic role of other proinflammatory cytokines, namely IL-2, IL-4, IL-6, and interferon (IFN)-gamma. Enzyme-linked immunosorbent assay of human explant culture supernatants revealed a significant increase in IFN-gamma production by AAA compared to occlusive (atherosclerotic) or normal (NL) aortic explants. IL-6 production was also increased in AAA compared to NL aortic explant supernatants. Neither AAA nor NL aortic tissues produced IL-2 or IL-4 in the same culture system. These results suggest that IL-6, a cytokine involved in T and B lymphocyte activation during inflammation, and IFN-gamma, which stimulates T and B lymphocytes, macrophages, endothelial cells and fibroblasts, may play a role in the pathogenesis of various vascular inflammatory diseases such as AAA.

Aorta, Abdominal↗

PubMed1994

Intercellular adhesion molecule-1 (ICAM-1) expression and soluble ICAM-1 (sICAM-1) production by cytokine-activated human aortic endothelial cells: a possible role for ICAM-1 and sICAM-1 in atherosclerotic aortic aneurysms.

The interactions of inflammatory cells, cytokines, and cell adhesion molecules (CAM) may be important in the pathogenesis of vascular diseases such as abdominal aortic aneurysms (AAA), in which inflammation plays a role. The aim of this study was to investigate the pathogenic role of ICAM-1, a molecule involved in leucocyte-endothelial interactions, in vascular inflammation. ELISA of human explant culture supernatants revealed a four-fold increase in sICAM-1 production by AAA (n = 9) versus normal (n = 8) aortic explants. Human aortic endothelial cell (hAEC) culture was used for further studies as an in vitro model for aortic inflammatory conditions. Tumour necrosis factor-alpha (TNF-alpha) or IL-1 beta treatment of hAEC resulted in an up to 1.8-fold significant increase in sICAM-1 production compared with resting cells. In addition, the expression of ICAM-1 on cytokine-stimulated versus resting hAEC was measured by radioimmunoassay. TNF-alpha significantly induced ICAM-1 expression on these cells. These results suggest that different forms of ICAM-1, present on or released by the activated aortic endothelium, may be involved in leucocyte adhesion to and migration into the vessel wall.

Aorta, Abdominal↗

PubMed1994

Interleukin-8 and tumor necrosis factor-alpha are involved in human aortic endothelial cell migration. The possible role of these cytokines in human aortic aneurysmal blood vessel growth.

Angiogenesis, the growth and proliferation of blood vessels, may be important in the pathogenesis of atherosclerosis and thus in human atherosclerotic abdominal aortic aneurysms (AAAs). Endothelial migration or chemotaxis is a vital component of the angiogenic response. Here, human aortic endothelial cells (hAECs) were used to investigate the effect of AAA tissue supernatants on hAEC chemotaxis. AAA tissue conditioned media were found to be chemotactic for hAECs. We have previously shown that the angiogenic cytokines interleukin (IL)-8, and tumor necrosis factor (TNF)-alpha are present in AAAs and normal aortic explant conditioned media. Currently, we have found that basic fibroblast growth factor (bFGF) and platelet-derived growth factor can also be detected in these supernatants. In order to identify whether some of these soluble mediators contributed to the chemotactic activity of these supernatants, conditioned media were preincubated with either neutralizing anti-IL-8, anti-TNF-alpha, anti-bFGF antibodies or control serum. Anti-IL-8 and anti-TNF-alpha significantly inhibited AAA tissue supernatant-induced hAEC chemotaxis (p < 0.05), while anti-bFGF did not (p not significant). These results indicate that IL-8 and TNF-alpha may be important in chemotactic activity for hAECs in vitro and possibly in AAA neovascularization. The abrogation of angiogenesis using neutralizing antibodies may be a future goal in the therapy of certain disease states such as AAA where angiogenesis plays an important role.

Antibodies, Monoclonal↗

PubMed1993

[Favorable in vitro effect of pentoxifylline on damaged lymphocyte migration in arteriosclerosis obliterans and systemic lupus erythematosus].

Decreased blood cell--e.g. lymphocyte--motility is seen in a number of vascular and autoimmune diseases. Pentoxifylline (Pf) shows a well-known therapeutic effect in several vascular alterations by causing the redistribution of blood cell cytoskeleton and increased microcirculation. As most literary data on Pf concern red blood cells and granulocytes authors here investigated the effect of Pf on previously decreased lymphocyte migration and chemotaxis. Results of in vitro studies suggest that Pf enhances impaired lymphocyte motility in obliterative arteriosclerosis and systemic lupus erythematosus and thus may also be introduced in the treatment of polysystemic autoimmune diseases.

Arteriosclerosis Obliterans↗

PubMed1993

In situ expression of cytokines and cellular adhesion molecules in the skin of patients with systemic sclerosis. Their role in early and late disease.

Cytokines and cellular adhesion molecules (CAMs) may play a role in the inflammatory and fibrotic processes underlying systemic sclerosis (SSc). We compared the immunohistological distribution of cytokines and CAMs in skin biopsies from 12 SSc patients and 14 normal (NL) individuals. Among CAMs, vascular cell adhesion molecule-1 (VCAM-1), which mediates leukocyte-endothelial adhesion, showed increased expression on SSc versus NL endothelium and stratum granulosum. P-selectin was up-regulated in SSc versus NL stratum granulosum. The CD44 lymphocyte homing receptor showed the most striking differences between SSc and NL: its expression was increased in SSc stratum granulosum, stratum spinosum, on lymphocytes, and macrophages. Regarding cytokines, interleukin-6 (IL-6) expression was increased on SSc versus NL endothelium and fibroblasts. Tumor necrosis factor-alpha (TNF-alpha) reactivity was more prevalent in SSc than NL stratum granulosum, whereas IL-8 expression was higher on SSc compared to NL endothelium. Some CAMs, such as VCAM-1 and P-selectin, and cytokines, namely TNF-alpha and IL-8, were more commonly found in skin biopsies taken from early (< or = 1 year's duration) SSc, while others, such as IL-6, showed up-regulation in the late stage of the disease. The results suggest that certain CAMs and cytokines may play a differential role in both the early, inflammatory, and the late, fibrotic stage of SSc.

Adult↗

PubMed1992

[Cell surface adhesion molecules: structure, function, clinical aspects].

Intercellular and cell-matrix interactions play a crucial role in several physiological and pathological processes. These relationships are based on different cell adhesion molecules. Although adhesion receptors exhibit structural diversity, cell adhesion mechanisms are basically similar to each other. Details of receptor functions (e.g. the exact mechanisms of signal transduction) is poorly understood. In this paper authors summarize data on different cell adhesion antigens and also describe a few important biological features to collect more data on the complex interactions of these molecules.

Cell Adhesion Molecules↗

PubMed1992

Lymphocyte adhesion to high endothelium is mediated by two beta 1 integrin receptors for fibronectin, alpha 4 beta 1 and alpha 5 beta 1.

Using a rat model we have previously proposed a role for fibronectin as an adhesive ligand on high endothelial cells (HEC) for recirculating lymphocytes. Lymphocyte adhesion to high endothelial cells was blocked by CS1 peptide (from the type III connecting segment of fibronectin) and RGD-containing peptides using two different in vitro assays of lymphocyte-HEC recognition, the frozen section assay and cultured HEC. In order to study the receptors utilised by lymphocytes to bind to HEC we have developed a xenogeneic model in which the adhesion of human lymphocytes to HEC cultured from rat lymph nodes is measured. The basic properties of lymphocyte-HEC interaction were retained using human lymphocytes. CS1 peptide and RGD-containing peptides gave similar profiles of inhibition of lymphocyte adhesion as found previously using rat cells. FACS analysis showed that the majority of peripheral blood lymphocytes expressed two beta 1 integrin receptors, alpha 4 beta 1 and alpha 5 beta 1, which are known to recognise distinct adhesion domains in fibronectin. A subpopulation of lymphocytes also expressed alpha 3 beta 1, which, like alpha 5 beta 1, has been reported to be an RGD-dependent adhesion receptor for the central cell binding domain of fibronectin. Anti-alpha 4 and anti-alpha 5 subunit monoclonal antibodies maximally inhibited adhesion to HEC by 60% and 65%, respectively. Monoclonal antibodies to the common beta 1 subunit gave slightly higher inhibition at 70%. These results suggest that lymphocytes employ one or both of two different beta 1 integrin fibronectin receptors to bind to HEC. The simultaneous or alternate engagement of two fibronectin receptors on the lymphocyte surface by immobilised fibronectin in the endothelial layer may contribute to the stabilisation of adhesive contacts or to the subsequent transendothelial migration of lymphocytes. In contrast to lymphocytes, peripheral blood neutrophils did not express any members of the beta 1 integrin family. The selective expression of beta 1 integrins by lymphocytes and not neutrophils contrasted with the widespread distribution of the other homing-associated adhesion molecules, LECAM-1, CD44 and LFA-1, on these two cell types. It is thus possible that the selective expression of beta 1 integrins regulates the constitutive migration of lymphocytes but not neutrophils into organised lymphoid tissues.

Amino Acid Sequence↗

PubMed1992

Nephritogenicity of anti-proteoglycan antibodies in experimental murine lupus nephritis.

BACKGROUND: Cross-reactivity between anti-DNA antibodies and heparan sulfate (HS)/heparan sulfate-proteoglycan (HS-PG) of glomerular basement membrane has been previously reported. Conceivably, this determines the final outcome of glomerular injury in lupus nephritis. EXPERIMENTAL DESIGN: We investigated the status of glomerular injury in NZB/NZW F1 mice after the administration of rabbit anti-HS-PG antibody (experiment group). The controls received normal rabbit IgG only. RESULTS: All experimental animals became proteinuric 2 weeks after the administration of anti-HS-PG. The animals of the older age group (16 weeks) had significant hematuria as well. Their glomeruli exhibited hypercellularity with a heavy influx of polymorphonuclear leukocytes and monocytes into their capillaries, and some of them exhibited crescentic changes. Electron-dense deposits were present in subepithelial, subendothelial, and mesangial regions of the glomeruli. The control group had normocellular glomeruli with a few mesangial deposits. Mouse IgG and C3 displayed a granular pattern of immunofluorescence in the experimental group. Anti-rabbit IgG titers in the serum were higher in the control group, which lower in the renal glomerular eluates. No significant differences were observed in the concentrations of anti-dsDNA and -ssDNA either in the sera or in the eluates. There was also no difference between the control and experimental group in terms of antibody synthesis by the splenic lymphocytes and their proliferation subsequent to antigenic challenge. CONCLUSIONS: Data suggest that administration of anti-HS-PG accentuates the glomerular injury during the natural course of lupus nephritis in (NZB/NZW F1 mice; seemingly these two antibodies (anti-HS-PG and -DNA) do not competitively inhibit the binding of the other to the same anionic sites of glomerular basement membrane enriched with heparan sulfate in vivo.

Animals↗

PubMed1991

Effect of pentoxifylline on decreased in vitro mononuclear leucocyte chemotaxis in vascular and polysystemic autoimmune diseases.

Impaired mononuclear leucocyte (MNL) motility can be found both in vascular and autoimmune diseases. Pentoxifylline (PTX) has a well-known therapeutic effect in vascular diseases, which is based on the rearrangement of blood cell cytoskeleton and thus increased microcirculatory flow. Most data on PTX concern red blood cells and granulocytes so now the effect of PTX on previously decreased MNL migration and chemotaxis was investigated in vitro. The results of MNL chemotaxis studies described here suggest that this drug enhances impaired MNL motility in obliterative atherosclerosis and systemic lupus erythematosus and thus may also be introduced in the treatment of certain polysystemic autoimmune diseases with decreased in vitro MNL chemotaxis.

Adult↗