Biomedical subjects

D Ribatti

Publications and source records attributed to D Ribatti.

At least 91 records · Page 5Linked to original sources

PubMed2000

Interferon beta-1a prevents the effects of lipopolysaccharide on embryonic brain microvessels.

By means of light and electron microscopy we have studied the effect of interferon beta-1a (IFNbeta-1a) in the optic tecta of 20-day-old chick embryos under normal conditions and after exposure to lipopolysaccharide (LPS) which mimics the blood-brain barrier (BBB) disruption in meningoencephalitis. Optic tecta were examined for: (i) ultrastructure by means of transmission electron microscopy; (ii) the immunohistochemical localization of HT7 antigen, a specific marker of differentiation of the brain microvessels; (iii) the brain microvessel permeability, by means of horseradish peroxidase (HRP) tracer; (iv) the expression of microvessel glycoconjugates, by means of lectin histochemistry, using Ricinus communis agglutinin-I (RCA-I), specific for beta-D-galactosyl moieties and Wheat Germ agglutinin (WGA) specific for sialyl and N-acetylglucosaminyl moieties. A morphometric evaluation of brain microvessel permeability and of glycoconjugate expression was also performed. In control- and in IFNbeta-1a-treated embryos, HRP was confined to the vessel lumina which were sealed by the interendothelial tight junctions. RCA-I binding sites were recognizable both in the basal membranes and in the tight junctions, while WGA sites were present on the luminal side of the endothelial cells. HRP was blocked in the vessels lumina by the interendothelial tight junctions. After LPS treatment, HRP showed an extravascular localization and the labeling of microvessels by anti-HT7 antibodies disappeared. RCA-I binding was only found ultrastructurally and appeared as irregularly clustered gold particles, in the cleft of damaged tight junctions, but were no longer detectable in the endothelial basement membranes. After pretreatment of LPS-treated embryos with IFNbeta-1a, the vessel permeability to HRP strongly decreased and the vessels showed the normal pattern of HT7 protein and of the RCA-I binding sites. These results indicate that the changes induced by LPS in the endothelial cells are prevented by IFNbeta-1a.

Animals↗

PubMed2000

Angiogenesis and mast cell density with tryptase activity increase simultaneously with pathological progression in B-cell non-Hodgkin's lymphomas.

Node biopsies of 16 benign lymphadenopathies and 72 B-cell non-Hodgkin's lymphomas (B-NHLs) were investigated for counts of microvessels, total metachromatic mast cells (MCs) and MCs expressing tryptase, an angiogenesis-inducing molecule. Counts were higher in B-NHLs. When grouped according to the Working Formulation (WF) malignancy grades, they were significantly higher in low-grade B-NHLs vs. lymphadenopathies and intermediate-grade vs. low-grade tumors and there was a further increase in the high-grade tumors. A high correlation was demonstrated in all groups of tissues between microvessel counts and both total metachromatic and tryptase-reactive MCs. These results suggest that angiogenesis in B-NHLs increases with their progression, and that MCs cooperate in its induction via the tryptase contained in their secretory granules.

Chymases↗

PubMed2000

An experimental study in the chick embryo chorioallantoic membrane of the anti-angiogenic activity of cyclosporine in rheumatoid arthritis versus osteoarthritis.

OBJECTIVE AND DESIGN: Angiogenesis plays an important role in the pathogenesis of rheumatoid arthritis (RA) and correlates with clinical score, synovial hyperplasia and infiltration of inflammatory cells. Many of the available treatments for RA have been shown to possess some degree of anti-angiogenic activity. Here, we studied the effect of cyclosporine, which exerts anti-angiogenic activity in vitro and in vivo [1] on angiogenesis induced in vivo in the chick embryo chorioallantoic membrane (CAM) by synovial RA and osteoarthritis (OA) tissues. MATERIAL AND METHODS: Wet synovial biopsies from 10 RA and 6 OA patients were treated with vehicle alone or with cyclosporine and implanted on the CAM at day 8 of incubation. On day 12, CAM tissues were assessed for the extent of angiogenesis and mononuclear cell infiltration. RESULTS: Cyclosporine inhibited angiogenesis and reduced the number of mononuclear cells in the CAM extracellular matrix only in RA implants. CONCLUSIONS: These data provide further evidence for a central role of new-formed blood vessels in RA. Moreover, cyclosporine on account of both its immunosuppressive and its anti-angiogenic activity can be proposed for the treatment of RA.

Allantois↗

PubMed2000

The discovery of angiogenic factors: a historical review.

Angiogenesis is a biological process by which new capillaries are formed and it occurs in many physiological and pathological conditions. It is controlled by the net balance between molecules that have positive and negative regulatory activity and this concept had led to the notion of the "angiogenic switch," depending on an increased production of one or more of the positive regulators of angiogenesis. Numerous inducers of angiogenesis have been identified and this review offers a historical account of the relevant literature concerning the discovery of the best-characterized angiogenic factors.

Angiogenesis Inducing Agents↗

PubMed2000

TNP-470 and recombinant human interferon-alpha2a inhibit angiogenesis synergistically.

The hypothesis that the combination of two known antiangiogenic agents TNP-470 and interferon (IFN)-alpha exerts synergistic effects has been investigated in vitro and in vivo. In vitro, TNP-470 and recombinant human IFN-alpha2a (rhIFN-alpha2a) resulted in a dose-dependent inhibition of proliferation of human umbilical vein endothelial cells (HUVECs) and EA.hy926 endothelial cells. Compared with the two agents used singly at their lowest or ineffective doses, combined treatment with the same doses inhibited more intensely in the absence of cytotoxicity and displayed similar behaviour on cell chemotaxis and capillary morphogenesis on Matrigel. However, the secretion of matrix metalloproteinase 2 (MMP-2) and MMP-9 was not influenced by the two agents, either alone or in combination, even when they were applied at their lowest efficacious doses or at higher cytotoxic doses. Experiments in vivo with the chick embryo chorioallantoic membrane (CAM)-sponge assay revealed the same dose-dependent inhibition and synergy. As the basic fibroblast growth factor (bFGF)-induced angiogenesis in the CAM-sponge model was strongly inhibited by the combined treatment, TNP-470 and rhIFN-alpha2a would appear to exert antiangiogenesis synergistically, perhaps by interfering with the bFGF-mediated pathway.

Angiogenesis Inhibitors↗

PubMed2000

Hematopoiesis and angiogenesis: a link between two apparently independent processes.

In early ontogeny, hematopoiesis is closely associated with angiogenesis. This article reviews recent studies on the role of angiogenic factors that regulate the proliferation and differentiation of endothelial cells in promoting hematopoietic cell growth and studies on the ability of hematopoietic cytokines to affect several endothelial cell functions. The findings in all these studies support the hypothesis formulated at the beginning of this century that a common ancestral cell, the hemangioblast, gives rise to cells of both the endothelial and the hematopoietic lineages.

Animals↗

PubMed2000

Proteolytic activity of human lymphoid tumor cells. Correlation with tumor progression.

Matrix metalloproteinase (MMP) expression and production are associated with advanced-stage tumor and contribute to tumor progression, invasion and metastases. The current study was designed to determine the expression and production of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) by human lymphoid tumor cells. Changes in expression and production were also investigated during tumor progression of multiple myeloma and mycosis fungoides. In situ hybridization analysis revealed that lymphoblastic leukemia B cells (SB cell line), multiple myeloma (MM) cells (U266 cell line) and lymphoblastic leukemia T cells (CEM and Jurkat cell lines) express constitutively the mRNA for MMP-2 and/or MMP-9. We demonstrated by gelatin-zymography of cell culture medium that both enzymes were secreted in their cleaved (activated) form. In situ hybridization of bone marrow plasma cells and gelatin-zymography of the medium showed that patients with active MM (diagnosis, relapse, leukemic progression) express higher levels of MMP-2 mRNA and protein than patients with non-active MM (complete/objective response, plateau) and with monoclonal gammopathies of undetermined significance (MGUS). MMP-9 expression and secretion was similar in all patient groups. In patients with mycosis fungoides (MF), the expression of MMP-2 and MMP-9 mRNAs was significantly upregulated with advancing stage, in terms of lesions both positive for one of two mRNAs and with the greatest intensity of expression. Besides MF cells, the MMP-2 and/or MMP-9 mRNAs were expressed by some stromal cell populations (microvascular endothelial cells, fibroblasts, macrophages), suggesting that these cells cooperate in the process of tumor invasion. Our studies identify MMPs as an important class of proteinases involved in the extracellular matrix (ECM) degradation by human lymphoid tumors, and suggest that MMPs inhibitors may lead to important new treatment for their control.

Humans↗

PubMed2000

The chick embryo chorioallantoic membrane as a model for in vivo research on anti-angiogenesis.

Anti-angiogenesis, i.e. inhibition of blood vessel growth, is being investigated as a way to prevent the growth of tumors and other angiogenesis-dependent diseases. Pharmacological inhibition interferes with the angiogenic cascade or the immature neovasculature with synthetic or semi-synthetic substances, endogenous inhibitors or biological antagonists. The chick embryo chorioallantoic membrane (CAM) is an extraembryonic membrane commonly used in vivo to study both new vessel formation and its inhibition in response to tissues, cells, or soluble factors. Angiogenesis or anti-angiogenesis is evaluated quantitatively or semiquantitatively. The fields of application of CAM in the study of anti-angiogenesis, including our personal experience, are illustrated in this paper.

Allantoin↗

PubMed2000

[Angiogenesis and tumor progression in melanoma].

Angiogenesis is defined as the formation of new blood capillaries from preexisting vessels. It takes place in physiological and pathological conditions, such as cancer. Tumor angiogenesis depends on the release of angiogenic growth factors by tumor cells and infiltrating inflammatory cells, and from the extracellular matrix following degradation by tumor proteases. Human melanoma progresses through different steps: nevocellular nevi, dysplastic nevi, in situ melanoma, radial growth phase melanoma (Breslow index < or = 0.75 mm), vertical growth phase melanoma (Breslow index > 0.75 mm), and metastatic melanoma. In agreement with progression, it acquires a rich vascular network, whereas an increasing proportion of tumor cells express the laminin receptor, which enables their adhesion to the vascular wall. Hence, both phenomena favour tumour cell extravasation and metastases. Melanocytic cells produce and release Fibroblast Growth Factor-2 (FGF-2), mainly in the steps of dysplastic nevus and melanoma in vertical growth phase. Melanoma cells also secrete the Vascular Endothelial Growth Factor (VEGF), in parallel with the switch from the radial to the vertical growth phase and the metastatic phase. It is becoming clear that anti-angiogenic agents will interfere with or block melanoma progression.

Cell Division↗

PubMed1999

Antiangiogenesis is produced by nontoxic doses of vinblastine.

The effects of vinblastine (VBL) on endothelial cell functions involved in angiogenesis, namely proliferation, chemotaxis, spreading on fibronectin (FN), secretion of matrix-metalloproteinase-2 (MMP-2) and MMP-9, and morphogenesis on Matrigel were tested in vitro, whereas its effects on angiogenesis were studied in vivo by using the chick embryo chorioallantoic membrane (CAM) model. In vitro, at noncytotoxic doses (0.1, 0.25, 0. 5, 0.75, and 1 pmol/L), VBL impacted all these functions, except secretion of MMPs, in a dose-dependent fashion. By contrast, proliferation of other primary cells such as fibroblasts and lymphoid tumor cells was not impacted. In vivo, VBL at 0.5, 0.75, and 1 pmol/L again displayed a dose-dependent antiangiogenic activity. Lack of cytotoxicity in vitro and in vivo was shown both morphologically, and also because the antiangiogenic effects were rapidly abolished when VBL was removed. Apoptosis was not induced. At the ultrastructural level, impairment of cell functions in vitro was associated with thin disturbance of the cytoskeleton, in the form of slight depolymerization and accumulation of microfilaments, which was equally reversible. Results suggest that VBL has an antiangiogenic component at very low, noncytotoxic doses, and that antiangiogenesis by VBL could be used to treat a wide spectrum of angiogenesis-dependent diseases, including certain chronic inflammatory diseases, Kaposi's sarcoma, and cancer.

Animals↗

PubMed1999

Purine analogue 6-methylmercaptopurine riboside inhibits early and late phases of the angiogenesis process.

Angiogenesis has been identified as an important target for antineoplastic therapy. The use of purine analogue antimetabolites in combination chemotherapy of solid tumors has been proposed. To assess the possibility that selected purine analogues may affect tumor neovascularization, 6-methylmercaptopurine riboside (6-MMPR), 6-methylmercaptopurine, 2-aminopurine, and adenosine were evaluated for the capacity to inhibit angiogenesis in vitro and in vivo. 6-MMPR inhibited fibroblast growth factor-2 (FGF2)-induced proliferation and delayed the repair of mechanically wounded monolayer in endothelial GM 7373 cell cultures. 6-MMPR also inhibited the formation of solid sprouts within fibrin gel by FGF2-treated murine brain microvascular endothelial cells and the formation of capillary-like structures on Matrigel by murine aortic endothelial cells transfected with FGF2 cDNA. 6-MMPR affected FGF2-induced intracellular signaling in murine aortic endothelial cells by inhibiting the phosphorylation of extracellular signal-regulated kinase-2. The other molecules were ineffective in all of the assays. In vivo, 6-MMPR inhibited vascularization in the chick embryo chorioallantoic membrane and prevented blood vessel formation induced by human endometrial adenocarcinoma specimens grafted onto the chorioallantoic membrane. Also, topical administration of 6-MMPR caused the regression of newly formed blood vessels in the rabbit cornea. Thus, 6-MMPR specifically inhibits both the early and the late phases of the angiogenesis process in vitro and exerts a potent anti-angiogenic activity in vivo. These results provide a new rationale for the use of selected purine analogues in combination therapy of solid cancer.

2-Aminopurine↗

PubMed1999

Developmental expression of ZO-1 antigen in the mouse blood-brain barrier.

Tight junction biogenesis during blood-brain barrier development (BBB) in mesencephalon microvessels of mouse embryos of day 9, foetuses of day 15 and 19 and new-born (2-day-old) mice was examined by light and electron microscopy, using monoclonal antibodies recognizing the tight junction peripheral membrane protein ZO-1. A faint spot-like staining began to be recognizable under the light microscope in day 15 vessels in which the endothelial cells showed isolated fusion points between the external plasma membrane leaflets under the electron microscope. A stronger labelling was present in microvessels of day 19 foetuses and new-born animals when the endothelial tight junction appeared completely differentiated. In the immunogold study, gold particles were seen scattered throughout the cytoplasm of endothelial cells of day 15 foetuses. In day 19 foetuses and in the new-born mice, gold particles were located only at the cytoplasmic surfaces of the tight junctions. The results indicate that the ZO-1 protein is a specific molecular marker in the developing brain endothelial tight junctions and that its expression takes place parallel to BBB morphofunctional maturation.

Aging↗

PubMed1999

Bone marrow neovascularization, plasma cell angiogenic potential, and matrix metalloproteinase-2 secretion parallel progression of human multiple myeloma.

To assess whether the progression of plasma cell tumors is accompanied by angiogenesis and secretion of matrix-degrading enzymes, bone marrow biopsy specimens from 20 patients with monoclonal gammopathy of undetermined significance (MGUS), 18 patients with nonactive multiple myeloma (MM), and 26 patients with active MM were evaluated for their angiogenic potential and matrix-metalloproteinase (MMP) production. A fivefold increase of the factor VIII+ microvessel area was measured by a planimetric method of point counting in the bone marrow of patients with active MM as compared with nonactive MM and MGUS patients (P <.01). When serum-free conditioned media (CM) of plasma cells isolated from the bone marrow of each patient were tested in vivo for their angiogenic activity in the chick embryo chorioallantoic membrane (CAM) assay, the incidence of angiogenic samples was significantly higher (P <. 01) in the active MM group (76%) compared with nonactive MM (33%) and MGUS (20%) groups. Moreover, a linear correlation (P <.01) was found between the extent of vascularization of the bone marrow of a given patient and the angiogenic activity exerted in the CAM assay by the plasma cells isolated from the same bone marrow. In vitro, a significantly higher fraction of the plasma cell CM samples from the active MM group stimulated human umbilical vein endothelial cell (HUVEC) proliferation (53%, P <.01), migration (42%, P <.05), and/or monocyte chemotaxis (38%, P <.05) when compared with nonactive MM and MGUS groups (ranging between 5% and 15% of the samples). Also, immunoassay of plasma cell extracts showed significantly higher (P <. 01) levels of the angiogenic basic fibroblast growth factor (FGF)-2 in the active MM patients than in nonactive MM and MGUS patients (153 +/- 59, 23 +/- 17, and 31 +/- 18 pg FGF-2/100 micrograms of protein, respectively). Accordingly, neutralizing anti-FGF-2 antibody caused a significant inhibition (ranging from 54% to 68%) of the biological activity exerted on cultured endothelial cells and in the CAM assay by plasma cell CM samples from active MM patients. Finally, in situ hybridization of bone marrow plasma cells and gelatin-zymography of their CM showed that active MM patients express significantly higher (P <.01) levels of MMP-2 mRNA and protein when compared with nonactive MM and MGUS patients, whereas MMP-9 expression was similar in all groups. Taken together, these findings indicate that the progression of plasma cell tumors is accompanied by an increase of bone marrow neovascularization. This is paralleled by an increased angiogenic and invasive potential of bone marrow plasma cells, which is dependent, at least in part, by FGF-2 and MMP-2 production. Induction of angiogenesis and secretion of MMPs by plasma cells in active disease may play a role in their medullary and extramedullary dissemination, raising the hypothesis that angiostatic/anti-MMP agents may be used for therapy of MM.

Adult↗

PubMed1999

Human erythropoietin induces a pro-angiogenic phenotype in cultured endothelial cells and stimulates neovascularization in vivo.

Hematopoietic and endothelial cell lineages share common progenitors. Accordingly, cytokines formerly thought to be specific for the hematopoietic system have been shown to affect several functions in endothelial cells, including angiogenesis. In this study, we investigated the angiogenic potential of erythropoietin (Epo), the main hormone regulating proliferation, differentiation, and survival of erythroid cells. Epo receptors (EpoRs) have been identified in the human EA.hy926 endothelial cell line by Western blot analysis. Also, recombinant human Epo (rHuEpo) stimulates Janus Kinase-2 (JAK-2) phosphorylation, cell proliferation, and matrix metalloproteinase-2 (MMP-2) production in EA.hy926 cells and significantly enhances their differentiation into vascular structures when seeded on Matrigel. In vivo, rHuEpo induces a potent angiogenic response in the chick embryo chorioallantoic membrane (CAM). Accordingly, endothelial cells of the CAM vasculature express EpoRs, as shown by immunostaining with an anti-EpoR antibody. The angiogenic response of CAM blood vessels to rHuEpo was comparable to that elicited by the prototypic angiogenic cytokine basic fibroblast growth factor (FGF2), it occurred in the absence of a significant mononuclear cell infiltrate, and it was not mimicked by endothelin-1 (ET-1) treatment. Taken together, these data demonstrate the ability of Epo to interact directly with endothelial cells and to elicit an angiogenic response in vitro and in vivo and thus act as a bona fide direct angiogenic factor.

Allantois↗

PubMed1999

Alterations of blood vessel development by endothelial cells overexpressing fibroblast growth factor-2.

A close relationship exists between angiogenesis and the formation of vascular lesions. The development of the vascular system in the chick embryo chorioallantoic membrane (CAM) may thus represent a model to study the effects of the deregulation of endothelial cell behaviour. Alterations of the developing vascular tree of the CAM were observed after exposure to murine aortic endothelial (MAE) cells overexpressing human fibroblast growth factor-2 (FGF2) cDNA (pZipFGF2 MAE cells), or to their conditioned medium (CM). pZipFGF2 MAE cells injected into the allantoic sac or applied on to the CAM of day 8-9 chick embryos induce neovascularization and the appearance of haemangioma-like lesions. This activity was not prevented by anti-FGF2 antibodies. The CM from pZipFGF2 MAE cells was also active when adsorbed into a gelatin sponge and applied on to the CAM, both in the absence and in the presence of anti-FGF2 antibodies. No effects on vessel development were exerted by parental MAE cells, FGF2-transfected NIH 3T3 fibroblasts, or their conditioned media. In vitro, pZipFGF2 MAE cell CM caused parental MAE cells to invade fibrin gels and to undergo morphogenesis on Matrigel. This activity was not mimicked by recombinant FGF2 nor affected by anti-FGF2 antibodies, and depended on a M (r) approximately 45 000 heat-labile heparin-binding factor. Size exclusion chromatography of pZipFGF2 MAE cell CM demonstrated that the in vitro activity co-purified with an in vivo angiogenic capacity. Thus, FGF2 overexpression in mouse endothelial cells induces the production of an angiogenic activity distinct from FGF2, which may contribute to the genesis of angioproliferative lesions.

Allantois↗

PubMed1999

Localization of factor VIII-related antigen in the endothelium of the chick embryo chorioallantoic membrane.

In this study, by using a polyclonal antibody against factor VIII-related antigen (FVIII-RA), we have examined the expression of FVIII-RA in the blood and lymphatic vessels of the chick embryo chorioallantoic membrane (CAM). The antibody marked the endothelium of blood and lymphatic vessels starting from day 8 of incubation and the cytoplasm of the allantoic epithelial cells. The application of this antibody may be useful for quantifying neovascularization in response to various angiogenic stimuli applied to the CAM.

Allantois↗

PubMed1999

Endogenous and exogenous fibroblast growth factor-2 modulate wound healing in the chick embryo chorioallantoic membrane.

Re-epithelization and the formation of a granulation tissue consisting of inflammatory cells, newly formed blood vessels, and fibroblasts embedded in a loose collagenous extracellular matrix, are critical events occurring during wound healing. In this study, utilizing the chick embryo chorioallantoic membrane (CAM) as an in vivo model of wound healing, we investigated the role of endogenous and exogenous fibroblast growth factor-2 (FGF-2) in the wound healing reparative processes. The results showed that: (1) neutralizing anti-FGF-2 antibodies (400 ng/embryo) decreased significantly the rate of wound healing (occurring only in 25% of specimens) when applied close to the edge of the wound, causing a significant decrease of microvessel and fibroblast density, and of an inflammatory macrophage infiltrate in the wounded area; (2) conversely, the application of exogenous recombinant FGF-2 (1.0 microg/embryo) greatly accelerated the wound repair occurring approximately 24h earlier than in untreated CAMs, stimulating angiogenesis, fibroblast proliferation, and macrophage infiltration. These findings demonstrate the role of FGF-2 in wound healing of the CAM and suggest that CAM, usually employed as an in vivo assay to study angiogenesis, can also be utilized as an in vivo model for the easy, rapid, and economic screening of molecules potentially able to affect the wound healing process.

Journal Article↗

PubMed1999

Bone marrow angiogenesis and mast cell density increase simultaneously with progression of human multiple myeloma.

Immunohistochemical, cytochemical and ultrastructural data showing vivid angiogenesis and numerous mast cells (MCs) in the bone marrow of 24 patients with active multiple myeloma (MM) compared with 34 patients with non-active MM and 22 patients with monoclonal gammopathy of undetermined significance (MGUS) led us to hypothesize that angiogenesis parallels progression of MM, and that MCs participate in its induction via angiogenic factors in their secretory granules.

Adult↗