Biomedical subjects

F Di Meglio

Publications and source records attributed to F Di Meglio.

5 recordsLinked to original sources

PubMed2003

Behavior of SaOS-2 cells cultured on different titanium surfaces.

Surface properties may affect the clinical outcome of titanium dental implants. The aim of the present study was to investigate the effects of 3 different titanium surfaces-smooth (S), sandblasted (SB), and titanium plasma-sprayed (TPS)-on proliferation, differentiation, and apoptosis of human osteoblast-like cells, SaOS-2. Cell proliferation was significantly (p < 0.05) higher on the S surface, and synthesis of extracellular matrix proteins was more abundant on TPS and SB than on S surfaces. Analysis of integrin receptors showed a higher expression of alpha2, alpha5, alphaVbeta3, and ss1 on TPS as compared with SB and S surfaces. An increase in alkaline phosphatase activity was detected only on SB and TPS surfaces. Analysis of cell apoptosis did not demonstrate any significant difference among the 3 different surfaces. The results indicate that titanium surface topography affects proliferation and differentiation of osteoblast-like SaOS-2 cells, suggesting that surface properties might be important for bone response around dental implants in vivo.

Alkaline Phosphatase↗

PubMed2003

Effect of human granulocyte macrophage-colony stimulating factor on differentiation and apoptosis of the human osteosarcoma cell line SaOS-2.

We investigated the effects of human granulocyte macrophage-colony stimulating factor (GM-CSF) on the relation between differentiation and apoptosis in SaOS-2 cells, an osteoblast-like cell line. To determine the relationship between these cellular processes, SaOS-2 cells were treated in vitro for 1, 7 and 14 days with 200 ng/mL GM-CSF and compared with untreated cells. Five nM insulin-like growth factor (IGF-I) and 30 nM okadaic acid were used as negative and positive controls of apoptosis, respectively. Effects on cell differentiation were determined by ECM (extracellular matrix) mineralization, morphology of some typical mature osteoblast differentiation markers, such as osteopontin and sialoprotein II (BSP-II), and production of bone ECM components such as collagen I. The results showed that treatment with GM-CSF caused cell differentiation accompanied by increased production of osteopontin and BSP-II, together with increased ECM deposition and mineralization. Flow cytometric analysis of annexin V and propidium iodide incorporation showed that GM-CSF up-regulated apoptotic cell death of SaOS-2 cells after 14 days of culture in contrast to okadaic acid, which stimulated SaOS-2 apoptosis only during the early period of culture. Endonucleolytic cleavage of genomic DNA, detected by "Aúladdering analysis"Aù, confirmed these data. The results suggest that GM-CSF induces osteoblastic differentiation and long-term apoptotic cell death of the SaOS-2 human osteosarcoma cell line, which in turn suggests a possible in vivo physiological role for GM-CSF on human osteoblast cells.

Apoptosis↗

PubMedDate not supplied

Basal lamina structural alterations in human asymmetric aneurismatic aorta.

Basal lamina (BL) is a crucial mechanical and functional component of blood vessels, constituting a sensor of extracellular microenvironment for endothelial cells and pericytes. Recently, an abnormality in the process of matrix microfibrillar component remodeling has been advocated as a mechanism involved in the development of aortic dilation. We focused our attention on BL composition and organization and studied some of the main components of the Extracellular Matrix such as Tenascin, Laminins, Fibronectin, type I, III and IV Collagens. We used surgical fragments from 27 patients, submitted to operation because of aortic root aneurysm and 5 normal aortic wall specimens from heart donors without any evidence for aneurysmal or atherosclerotic diseases of the aorta. Two samples of aortic wall were harvested from each patient, proximal to the sinotubular junction at the aortic convexity and concavity. Each specimen was processed both for immunohistochemical examination and molecular biology study. We compared the convexity of each aortic sample with the concavity of the same vessel, and both of them with the control samples. The synthesis of mRNA and the levels of each protein were assessed, respectively, by RT-PCR and Western Blot analysis. Immunohistochemistry elucidated the organization of BL, whose composition was revealed by molecular biology. All pathological samples showed a wall thinner than normal ones. Basal lamina of the aortic wall evidentiated important changes in the tridimensional arrangement of its major components which lost their regular arrangement in pathological specimens. Collagen I, Laminin alpha2 chain and Fibronectin amounts decreased in pathological samples, while type IV Collagen and Tenascin synthesis increased. Consistently with the common macroscopic observation that ascending aorta dilations tend to expand asymmetrically, with prevalent involvement of the vessel convexity and relative sparing of the concavity, Collagen type IV is more evident in the concavity and Tenascin in the convexity.

Adult↗

PubMedDate not supplied

Extra cellular matrix features in human meninges.

We collected human fetal and adult normal meninges to relate the age of the tissue with the presence of collagenous and non-collagenous components of Extra Cellular Matrix (ECM). Immunohistochemistry led us to observe some differences in the amount and in the distribution of these proteins between the two sets of specimens. In particular, laminin and tenascin seem to be expressed more intensely in fetal meninges when compared to adult ones. In order to investigate whether the morphofunctional characteristics of fetal meninges may be represented in pathological conditions we also studied meningeal specimens from human meningiomas. Our attention was particularly focused on the expression of those non-collagenous proteins involved in nervous cell migration and neuronal morphogenesis as laminin and tenascin, which were present in lesser amount in normal adult specimens. Microscopical evidences led us to hipothesize that these proteins which are synthesized in a good amount during the fetal development of meninges can be newly produced in tumors. On the contrary, the role of tenascin and laminin in adult meninges is probably only interesting for their biophysical characteristics.

Adult↗

PubMedDate not supplied

Different titanium surfaces modulate the bone phenotype of SaOS-2 osteoblast-like cells.

Commercially pure titanium implants presenting a relatively smooth, machined surface or a roughened endosseous surface show a large percentage of clinical success. Surface properties of dental implants seem to affect bone cells response. Implant topography appears to modulate cell growth and differentiation of osteoblasts affecting the bone healing around the titanium implant. The aim of the present study was to examine the effects of 1cm diameter and 1mm thick titanium disks on cellular morphology, adhesion and bone phenotypic expression of human osteoblast-like cells, SaOS-2. SaOS-2 cells were cultured on commercially 1 cm pure titanium disks with three different surface roughness: smooth (S), sandblasted (SB) and titanium plasma sprayed (TPS). Differences in the cellular morphology were found when they were grown on the three different surfaces. An uniform monolayer of cells recovered the S surface, while clusters of multilayered irregularly shaped cells were distributed on the rough SB and TPS surfaces. The adhesion of SaOS-2 cells, as measured after 3h of culture, was not affected by surface roughness. ECM components such as Collagen I (CoI), Fibronectin (FN), Vitronectin (VN) and Tenascin (TN) were secreted and organized only on the SB and TPS surfaces while they remained into the cytoplasm on the S surfaces. Osteopontin and BSP-II were largely detected on the SB and TPS surfaces, while only minimal production was observed on the S ones. These data show that titanium surface roughness affects bone differentiation of osteoblast like-cells, SaOS-2, indicating that surface properties may be able to modulate the osteoblast phenotype. These observations also suggest that the bone healing response around dental implants can be affected by surface topography.

Bone and Bones↗