R.U. PROF. ADRIANA BIGI - University of Bologna
The scientific activity of the research unit of Prof.
Bigi is addressed to investigate the chemical and
structural aspects of the biomineralization processes,
which can be regarded as model systems for the design
and development of new composite materials with possible
applications as biomaterials. Indeed, the
organic/inorganic composites synthesized by living
organisms often display unique and desirable
morphological, structural and mechanical properties, and
represent informative models for the design and
synthesis of complex functional materials.
Present research interests:
- Synthesis and characterization of nano- and
microcrystalline inorganic phases through biomimetic
approach
- Hybrid materials constituted of calcium phosphates and
biological active molecules
- Oriented growth of inorganic phases on functionalized
polymeric and metallic matrices
Design and development of new biomaterials for
applications in the orthopaedic, dental and
cardiovascular surgery fields, including calcium
phosphate bone cements, calcium phosphate- polymers
composites, coatings of metallic substrates.
R.U. PROF. ELISABETTA WEBER - University of
Siena
The main topic of research of the unit of Prof.
Elisabetta Weber is the study of lymphatic endothelium
in tissue sections and in culture.
The interactions of endothelial cells with the
extracellular matrix have been evaluated on the basis of
fibrillin deposition in relation to the expression of
Microfibril Associated Glycoprotein-1 (MAGP-1).
In blood endothelial cells fibrillin deposition and
MAGP-1 expression correlate, whereas in lymphatic
endothelial cells MAGP-1 is expressed later than
fibrillin and in negligible amount. Since fibrillin
forms the scaffold for elastin deposition, a different
pattern of fibrillin deposition may determine the
specificity of elastic fibres in relation to the
different functional requirements of lymphatic versus
blood vessels.
Fibrillin, produced by endothelial cells and deposited
in the extracellular matrix, contains an RGD group that
may bind integrins. These molecules, with their
cytoplasmic tail, trigger the activation of a cascade of
molecules inside the cell, including the phosphorylation
of FAK (Focal Adhesion Kinase), that induces the
reorganization of cytoskeletal b-actin and hence the
adaptation of cell shape to the substrate.
In collaboration with Prof.R.Barbucci, director of
C.R.I.S.M.A., we have evaluated the interactions of
lymphatic endothelial cells with microstructured
surfaces with alternating stripes of hyaluronic acid
(Hyal) and aminosilanized glass obtained by the method
of photoimmobilization. Cells grew only on glass,
avoiding Hyal stripes, aligned along the stripes and
expressed integrins, indicating that their adhesion to
the substrate was integrin-mediated.
In collaboration with Prof.Barbucci, we have also
evaluated the role of the Hyal-Cu complex on the
behaviour of blood and lymphatic endothelial cells on
striped micropatterns obtained by the
photoimmobilization of Hyal-Cu on aminosilanized glass.
Blood endothelial cells tended to migrate from glass to
Hyal-Cu stripes, whereas lymphatic endothelial cells did
not migrate on Hyal-Cu and remained on glass.
R.U. PROF. MARINA ZICHE - University of Siena
The laboratory of Prof. Marina Ziche focuses on research
of the endothelium with particular emphasis on
angiogenesis, one of the principal functions of this
tissue. Angiogenesis, a process which leads to the
formation of new vessels, has a relevant physiological
role during development and in adult life. The
involvement of angiogenesis in pathologies, particularly
cancer, but also cardiovascular and neurodegenerative
diseases, has sparked an intense research interest in
this phenomenon.
The involvement of angiogenesis is crucial during tissue
repair and in the integration of synthetic biomaterials
and medical devices used for surgical and reparative
surgery.
Since the group participated together with other CRISMA
groups to the FIRB 2001 project (“Technologies for the
nanometric manipulation of biomaterials and their
biomedical application”, coordinated by Prof. Barbucci),
the Ziche Unit studied and is studying the behaviour of
endothelial cells on different biomaterials provided the
chemist units within the project.
In particular microvascular endothelial cells are used,
since microcirculation is the site for vascular
remodelling and angiogenesis. The parameters under
investigation are cell survival at short and long time,
evaluated by biochemical assays and SEM analysis,
parameters linked to morphology, adhesion and
organization of the cytoskeleton (beta-actin, tubulin,
integrins and extracellular matrix proteins), parameters
of endothelial functions (expression and activity of
constitutive nitric oxide synthase), parameters of
inflammation (inducible cycloxygenase-2). Other
parameters specifically associated with angiogenesis are
the answer to specific angiogenic factors as VEGF
(vascular endothelial growth factor), the transcription
and release of FGF-2 (fibroblast growth factor-2) and
matrix metalloproteinases.
The Unit is completing the characterization of
endothelial cell behaviour on micro and nanostructured
surfaces (PET, glass) with different coatings to allow
the adhesion and growth of endothelial cells, or, on the
contrary, of surfaces which do not allow endothelial
adhesion.
Other biomaterials which have been characterized by the
Unit and are designed for a potential use in mineralized
tissue (bone) repair and substitution are hydroxyapatite
nanocrystals and titanium alloys. Both materials have
been demonstrated to show a good biocompatibility for
endothelial cells which maintain their biological
functions, not acquiring proinflammatory
characteristics, but on the contrary a well controlled
proangiogenic phenotype. |
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