Biomedical subjects

A Vacca

Publications and source records attributed to A Vacca.

At least 109 records · Page 6Linked to original sources

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

Thrombospondin-1 is a mediator of the neurotypic differentiation induced by EGF in thymic epithelial cells.

Thymic epithelial cell component originates from cranial neural crest as well as from endoderm and ectoderm of the third pharyngeal pouch and branchial cleft. Epidermal growth factor (EGF) has been previously shown to play a crucial role in directing thymic epithelial cells toward a neural-oriented cell fate. To identify genes that are involved in the EGF-induced neurotypic differentiation of the thymic stroma-derived TC-1S cell line, we studied EGF-treated and untreated cells by RNA fingerprinting PCR-based differential screening. We obtained 23 distinct sequences including 18 known genes and 5 sequences previously unreported, which are currently under characterization. Here, we describe the involvement of one of the isolated genes, the thrombospondin-1, as a mediator of the neurotypic differentiation induced by EGF in TC-1S cells. We show that thrombospondin-1 mRNA and protein levels are increased by EGF. Moreover, exogenous thrombospondin-1 is able to enhance the outgrowth of neurite-like processes as well as the expression of neurofilaments and neural cell adhesion molecule in TC-1S cells. These observations suggest that the up-regulation of thrombospondin-1 synthesis induced by EGF contributes to the differentiation choice of thymic epithelial cells toward a neural fate, reminiscent of their neural crest origin.

Animals↗

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

Bleomycin-induced scleroderma: report of a case with a chronic course rather than the typical acute/subacute self-limiting form.

We report a case of bleomycin-induced scleroderma in a 35-year-old woman treated with chemotherapy for Hodgkin's disease. Approximately 6 months after the first chemotherapy cycle, the patient developed skin sclerosis in both arms. The lesion showed no signs of spontaneous clinical amelioration and treatment with steroids was unsuccessful. A partial remission of the skin sclerosis was instead obtained by the administration of D-penicillamine. A family history revealed other cases of autoimmune diseases and HLA typing showed the presence of antigens associated with scleroderma. The association between bleomycin therapy and scleroderma is discussed.

Adult↗

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↗

PubMed1999

Angiogenesis extent and macrophage density increase simultaneously with pathological progression in B-cell non-Hodgkin's lymphomas.

Node biopsies of 30 benign lymphadenopathies and 71 B-cell non-Hodgkin's lymphomas (B-NHLs) were investigated for microvessel and macrophage counts using immunohistochemistry and morphometric analysis. Both counts were significantly higher in B-NHL. Moreover, when these were grouped into low-grade and high-grade lymphomas, according to the Kiel classification and Working Formulation (WF), statistically significant higher counts were found in the high-grade tumours. Immunohistochemistry and electron microscopy revealed a close spatial association between microvessels and macrophages. Overall, the results suggest that, in analogy to what has already been shown in solid tumours, angiogenesis occurring in B-NHLs increases with tumour progression, and that macrophages promote the induction of angiogenesis via the release of their angiogenic factors.

Antigens, CD↗

PubMed1999

The role of the vascular phase in solid tumor growth: a historical review.

Angiogenesis is a biological process by which new capillaries are formed from pre-existing vessels. It occurs in both physiological conditions such as embryo development, cyclically in the female genital system and during wound repair, and pathological conditions, such as arthritis, diabetic retinopathy and tumors. In solid tumor growth, a specific critical turning point is the transition from the avascular to the vascular phase. Having developed an intrinsic vascular network, the neoplastic mass is able to grow indefinitely (unlike all the other forms, tumor angiogenesis is not limited in time) both in situ and at distant sites (metastasis) in so far as an intrinsic vascular network enables its cells to enter the vascular bed and colonize other organs. Tumor angiogenesis depends mainly on the release by neoplastic cells of growth factors specific for endothelial cells and able to stimulate growth of the host's blood vessels. This review describes its history as traced by the main contributions to the international medical literature and their contents. The specific new paradigm discussed here has been gaining general approval and considerable confirmation, thanks to its possible applications, as recently highlighted by the introduction of anti-angiogenic substances in adjuvant tumor management.

Animals↗

PubMed1999

Angiogenesis extent and expression of matrix metalloproteinase-2 and -9 correlate with upgrading and myometrial invasion in endometrial carcinoma.

BACKGROUND: Changes in angiogenesis and expression of extracellular matrix-degrading enzymes have been substantiated during tumour changeover and progression. METHODS: Tissues from 64 biopsies of endometrial carcinoma (EC) and 15 biopsies of normal (control) endometrium were investigated immunohistochemically to determine their microvessel number, and by in situ hybridisation to determine the expression of mRNA of the matrix metalloproteinase-2 (MMP-2, gelatinase A) and metalloproteinase-9 (MMP-9 gelatinase B). EC were grouped according to both histological grade (G) G1 to G3 and depth of myometrial (M) invasion M1 to M3. RESULTS: EC as a whole gave significantly higher counts over control endometria. Counts of the G1 group overlapped those of the control group, increased significantly in the G2 and even more in the G3 group. G3 biopsies in particular also displayed most microvessels widely scattered in the tumour tissue, in close association with tumour cells, and as winding and arborized tubes, often dilated in microaneurysmatic segments. Counts also increased in M2 and M3. Expression of the MMP-2 and MMP-9 mRNA, evaluated as percentages of positive biopsies and intensity of expression, were upregulated with the transition from control and G1 groups to G2 and G3, and in relation to advancing depth of invasion. In EC, MMP-2 and MMP-9 mRNA were also expressed by host stromal cells, including microvascular endothelial cells, fibroblasts and macrophages. In the control biopsies, poor expression of MMP-2 mRNA in few endothelial cells and no expression of MMP-9 mRNA were detected. CONCLUSION: These in situ data suggest that angiogenesis and degradation of extracellular matrix occur simultaneously with EC upgrading and advancing depth of invasion, and that EC cells and some host stromal cell populations cooperate in tumour progression.

Adult↗

PubMed1999

Temporal expression of the matrix metalloproteinase MMP-2 correlates with fibronectin immunoreactivity during the development of the vascular system in the chick embryo chorioallantoic membrane.

In this study we have examined in the chick embryo chorioallantoic membrane (ChAM) the expression of the matrix metalloproteinase 2 (MMP-2) and have correlated this parameter with the expansion of the ChAM vasculature and with the expression of 3 extracellular matrix components (fibronectin, laminin and type IV collagen), which differentially modulate angiogenesis. In the early phases of ChAM development, between d 6 and d 8 of incubation, when the increase of the ChAM vasculature is maximal, higher values of MMP-2 and, respectively, of fibronectin immunoreactive area, are detectable. These results indicate that MMP-2 activity and fibronectin expression are 2 strictly related components of angiogenesis occurring in vivo.

Animals↗

PubMed1999

Expression pattern of notch1, 2 and 3 and Jagged1 and 2 in lymphoid and stromal thymus components: distinct ligand-receptor interactions in intrathymic T cell development.

The suggested role of Notch1 or its mutants in thymocyte differentiation and T cell tumorigenesis raises the question of how the different members of the Notch family influence distinct steps in T cell development and the role played by Notch ligands in the thymus. We report here that different Notch receptor-ligand partnerships may occur inside the thymus, as we observed differential expression of Notch1, 2 and 3 receptors, their ligands Jagged1 and 2, and downstream intracellular effectors hairy and Enhancer of Split homolog 1 (HES-1) and hairy and Enhancer of Split homolog 5 (HES-5), depending on ontogenetic stage and thymic cell populations. Indeed, while Jagged2 is expressed in both stromal cells and thymocytes, Jagged1 expression is restricted to stromal cells. Moreover, a differential distribution of Notch3, with respect to Notch1, was observed in distinct age-related thymocyte subsets. Finally, Notch3 was preferentially up-regulated in thymocytes, following the induction of their differentiation by interaction with thymic epithelial cells expressing the cognate Jagged1 and 2 ligands, suggesting that, besides Notch1, Notch3 may also be involved in distinct steps of thymocyte development. Our results suggest that the Notch signaling pathway is involved in a complex interplay of T cell developmental stages, as a consequence of the heterogeneity and specific expression of members of the Notch receptor family and their cognate ligands, in distinct thymic cell compartments.

Animals↗

PubMed1999

In vivo angiogenic activity of urokinase: role of endogenous fibroblast growth factor-2.

In vitro experimental evidences suggest that the proteolytic degradation of the extracellular matrix (ECM) by activation of the urokinase-type plasminogen activator (uPA)/plasmin system may affect growth factor activity and bioavailability. However, no direct in vivo observations were available to support this hypothesis. Here we demonstrate that endothelial GM 7373 cells overexpressing human uPA (uPA-R5 cells) cause the release of (125)I-labeled fibroblast growth factor-2 (FGF2) from endothelial ECM in a plasmin-dependent manner. Accordingly, uPA-R5 cells are angiogenic in vivo when applied on the top of the chorioallantoic membrane (CAM) of the chick embryo. In contrast, mock-transfected Neo2 cells are unable to release ECM-bound (125)I-FGF2 and are poorly angiogenic. Neovascularization elicited by uPA-R5 cells is significantly reduced by neutralizing anti-FGF2 antibodies to values similar to those observed in Neo2 cell-treated CAMs. Accordingly, purified human uPA stimulates neovascularization of the CAM in the absence of an inflammatory response. The angiogenic activity of uPA is significantly inhibited by neutralizing anti-FGF2 antibodies or by pretreatment with phenylmethylsulfonyl fluoride. The non-catalytic, receptor-binding amino-terminal fragment of uPA is instead non angiogenic. Taken together, the data indicate that uPA is able to induce angiogenesis in vivo via a plasmin-dependent degradation of ECM that causes the mobilization of stored endogenous FGF2.

Allantois↗

PubMed1999

Angiogenesis in lipoma: An experimental study in the chick embryo chorioallantoic membrane.

Lipoma is one of the most common benign mesenchymal tumors. Its ability to trigger an angiogenic response is a critical step for its growth. Because adipose tissue serves as an important conduit for the vasculature, it is conceivable that the angiogenic properties of this tissue may modulate the growth of the vasculature in a paracrine manner. We investigated in vivo the angiogenic potential of bioptic fragments of human lipoma by using the chick embryo chorioallantoic membrane (CAM), a useful model for such an investigation. The angiogenic response in pathological and control implants was assessed on histologic sections by a morphometric method, 96 h after grafting. Results showed that pathological samples were surrounded by numerous allantoic vessels with a radially arranged pattern around the implant. The vascular counts in the CAMs treated with lipoma implants were comparable to that of FGF-2. The role played in vasoproliferative response by angiogenic cytokines (FGF-2, VEGF) released by adipocytes, by endogenous cytokines, such as FGF-2, stored in the CAM extracellular matrix and by angiogenic growth factors released by perivascular mononuclear cells around the newly-formed blood vessels, were supported by this study.

Adult↗

PubMed1999

Transcriptional up-regulation of matrix metalloproteinase-9 expression during spontaneous epithelial to neuroblast phenotype conversion by SK-N-SH neuroblastoma cells, involved in enhanced invasivity, depends upon GT-box and nuclear factor kappaB elements.

Spontaneous epithelial (S) to neuroblast (N) conversion enhanced the capacity of SK-N-SH neuroblastoma (NB) cells to invade reconstituted basement membrane in vitro. This involved a switch to matrix metalloproteinase (MMP) activity, in particular MMP-9, and was associated with the induction of MMP-9 expression. N-type-specific MMP-9 expression was herbimycin A inhibitable tyrosine kinase (possibly c-src) dependent and was regulated transcriptionally through GT-box (-52), and nuclear factor kappaB (NFkappaB; -600) elements within the MMP-9 gene. GT-box function was associated with elevated levels of specific nuclear GT-box binding complexes in N-type cells. NFkappaB function was associated with specific p50- and p65-containing nuclear NFkappaB binding complex(es). No function could be attributed to the proximal AP-1 (-79) element, and minimal function was attributed to the SP-1 (-560), ets (-540), or distal AP-1 (-533) elements. This was despite elevated levels of specific junD/fra-1 containing proximal AP-1 element binding complex(es) in N-type cells. Our data highlight a pivotal role for the GT-box, in concert with the NFkappaB element, in the transcriptional up-regulation of MMP-9 expression during spontaneous S to N phenotype conversion by SK-N-SH cells involved in enhanced basement membrane invasivity.

Benzoquinones↗

PubMed1998

Human neuroblastoma cells produce extracellular matrix-degrading enzymes, induce endothelial cell proliferation and are angiogenic in vivo.

Direct experimental evidence shows that tumor growth and metastases are angiogenesis-dependent. Neuroblastoma (NB) is the most common extracranial malignant solid tumor of childhood. In this study, we investigated 2 human NB cell lines, LAN-5 and GI-LI-N, for their capacity to secrete 2 extracellular matrix-degrading enzymes, MMP-2 and MMP-9, and to induce in vitro human microvascular endothelial cells (EC) to proliferate and in vivo angiogenesis in the chick embryo chorio-allantoic membrane (CAM) assay. Conditioned medium (CM) from both cell lines stimulated in vitro EC proliferation and the effect of LAN-5 CM was higher than that of GI-LI-N cells. Moreover, anti-VEGF, but not anti-FGF2 antibodies, prevented growth increment of EC. NB cell lines secreted the active form of MMP-2 almost exclusively, LAN-5 cells more than GI-LI-N cells. Both cell lines, LAN-5 cells more than GI-LI-N ones, induced angiogenesis in the CAM assay. Our data suggest that the 2 NB cell lines are angiogenic, to LAN-5 cells more than GI-LI-N ones. LAN-5 cells are indeed endowed with a more aggressive and invasive phenotype.

Allantois↗

PubMed1998

TIMP-2 over-expression reduces invasion and angiogenesis and protects B16F10 melanoma cells from apoptosis.

The matrix metalloproteinase (MMP) inhibitor TIMP-2 has a high specificity for gelatinase A/MMP-2. An imbalance between gelatinase A and TIMP-2 in favor of enzymatic activity is linked to the degradation of the extracellular matrix (ECM) associated with several physiologic and pathologic events, including angiogenesis, invasion and metastasis. Since TIMPs are secreted molecules, they have the potential to be used for gene therapy of certain tumors. We transfected B16F10 murine melanoma cells, a highly invasive and metastatic cell line, with an expression vector harboring a cDNA encoding for human TIMP-2. The clones obtained were isolated and examined for TIMP-2 over-expression and changes in tumor cell phenotype. The amount of recombinant TIMP-2 produced correlated with a reduction in invasion. In an in vivo angiogenesis assay, TIMP-2-transfected clones showed reduced levels of blood vessel formation, and in vitro conditioned media from TIMP-2 transfectants showed diminished induction of endothelial cell migration and invasion. TIMP-2 over-expression limited tumor growth in vivo and neoangiogenesis when cells were injected subcutaneously in mice in the presence of Matrigel. However, TIMP-2 overexpressing clones were found to be more resistant to apoptosis than parental and control melanoma cells, while necrosis was increased. Our data confirm the role of TIMP-2 in the down-regulation of metastasis and angiogenesis but indicate a possible involvement in tumor cell survival.

Animals↗

PubMed1998

Systemic sclerosis stimulates angiogenesis in the chick embryo chorioallantoic membrane.

Skin biopsies from patients with systemic sclerosis (SSc) were investigated for their angiogenic activity by using the chick embryo chorioallantoic membrane (CAM) assay. Ten samples of SSc and 10 of normal skin from age- and sex-matched subjects were grafted onto the CAM, and the angiogenic response in pathological and control implants was assessed on histological sections by a planimetric point-count method 4 days after grafting. The vascular counts in the area underlying the SSc were significantly higher than those of normal skin and a dense mononuclear cell infiltrate was detectable around the blood vessels in pathological specimens. These results suggest that SSc may promote angiogenesis, perhaps leading to the release of several angiogenic factors. Moreover, the role played in the angiogenic response by the inflammatory cells forming the cellular infiltrate is suggested by this study.

Adult↗