454 research outputs found
New perspectives in cartilage medicine: Latest biology insights can redirect future cartilage medical strategies?
Electrospun silk fibroin fibers for storage and controlled release of human platelet lysate
Human platelet lysate (hPL) is a pool of growth factors and cytokines able to induce regeneration of different tissues. Despite its good potentiality as therapeutic tool for regenerative medicine applications, hPL has been only moderately exploited in this field. A more widespread adoption has been limited because of its rapid degradation at room temperature that decreases its functionality. Another limiting factor for its extensive use is the difficulty of handling the hPL gels. In this work, silk fibroin-based patches were developed to address several points: improving the handling of hPL, enabling their delivery in a controlled manner and facilitating their storage by creating a device ready to use with expanded shelf life. Patches of fibroin loaded with hPL were synthesized by electrospinning to take advantage of the fibrous morphology. The release kinetics of the material was characterized and tuned through the control of fibroin crystallinity. Cell viability assays, performed with primary human dermal fibroblasts, demonstrated that fibroin is able to preserve the hPL biological activity and prolong its shelf-life. The strategy of storing and preserving small active molecules within a naturally-derived, protein-based fibrous scaffold was successfully implemented, leading to the design of a biocompatible device, which can potentially simplify the storage and the application of the hPL on a human patient, undergoing medical procedures such as surgery and wound care. Statement of Significance: Human platelets lysate (hPL) is a mixture of growth factors and cytokines able to induce the regeneration of damaged tissues. This study aims at enclosing hPL in a silk fibroin electrospun matrix to expand its utilization. Silk fibroin showed the ability to preserve the hPL activity at temperature up to 60 \ub0C and the manipulation of fibroin's crystallinity provided a tool to modulate the hPL release kinetic. This entails the possibility to fabricate the hPL silk fibroin patches in advance and store them, resulting in an easy and fast accessibility and an expanded use of hPL for wound healing
Encapsulation of human articular chondrocytes into 3D hydrogel : phenotype and genotype characterization
This chapter is intended to provide a summary of the current materials used in cell encapsulation technology
as well as methods for evaluating the performance of cells encapsulated in a polymeric matrix. In
particular, it describes the experimental procedure to prepare a hydrogel matrix based on natural polymers
for encapsulating and culturing human articular chondrocytes with the interest in cartilage regeneration.
Protocols to evaluate the viability, proliferation, differentiation, and matrix production of
embedded cells are also described and include standard protocols such as the MTT and [3H] Thymidine
assays, reverse transcription polymerase chain reaction (RT-PCR) technique, histology, and immunohistochemistry
analysis. The assessment of cell distribution within the 3D hydrogel construct is also described
using APoTome analysis.(undefined
Novel injectable gel encapsulating human articular chondrocytes for cartilage tissue repair and regeneration
[Excerpt] Cartilage tissue loss, as a result of trauma, congenital disorders and diseases of joints, involving structural damage of articular cartilage surface, is a substantial clinical problem representing a major
challenge for cartilage tissue engineering. The aim of our study was to evaluate the in vitro and in vivo behavior of human articular chondrocytes encapsulated within a novel carrageenan in situ injectable
hydrogel for cartilage tissue engineering and regeneration. Human articular chondrocytes (Hac) were expanded using a well defined serum free medium able to support cell proliferation and
differentiation with high cell chondrogenicity. [...]info:eu-repo/semantics/publishedVersio
Beta-tricalcium phosphate ceramic triggers fast and robust bone formation by human mesenchymal stem cells
Due to their osteoconductive and inductive properties, a variety of calcium phosphate (CaP) scaffolds are commonly used in orthopaedics as graft material to heal bone defects. In this study, we have used two CaP scaffolds with different hydroxyapatite (HA) and \u3b2-tricalcium phosphate (\u3b2-TCP) ratios (MBCP\uae; 60/40 and MBCP+\uae; 20/80) to investigate their intrinsic capacity to favour human bone marrow stem cells (hBMSCs) osteogenic differentiation capacity. We report that MBCP+\uae showed in in vitro culture model a higher rate of calcium ion release in comparison with MBCP\uae. In two defined coculture systems, the hBMSC seeded onto MBCP+\uae presented an increased amount of VEGF secretion, resulting in an enhanced endothelial cell proliferation and capillary formation compared with hBMSC seeded onto MBCP\uae. When both ceramics combined with hBMSC were implanted in a nude mouse model, we observed a faster osteogenic differentiation and enhancement mature bone deposition sustained by the presence of a vast host vasculature within the MBCP+\uae ceramics. Bone formation was observed in samples highly positive to the activation of calcium sensing receptor protein (CaSr) on the surface of seeded hBMSC that also shown higher BMP-2 protein expression. With these data we provide valuable insights in the possible mechanisms of ossification and angiogenesis by hBMSC that we believe to be primed by calcium ions released from CaP scaffolds. Evidences could lead to an optimization of ceramic scaffolds to prime bone repair
Platelet lysate maintains chondrogenic potential and promotes cartilage regeneration
cartilage.
We
report
the
biological
effect
of
the
platelet
lysate
(PL),
a
PRP
derivative,
on
primary
human
articular
chondrocytes
(HAC)
cultured
under
both
physiological
and
inflammatory
condition.
Added
to
the
culture
medium,
PL
induced
a
strong
mitogenic
response
in
the
chondrocytes.
The
in
vitro
expanded
cell
population
maintained
a
chondrogenic
re-Ââdifferentiation
potential
as
revealed
by
micromass
culture
in
vitro
as
well
as
in
vivo
as
demonstrated
by
ectopic
cartilage
formation
in
nude
mice.
Furthermore,
in
chondrocytes
cultured
in
the
presence
of
the
pro-Ââinflammatory
cytokine
IL-Ââ1α,
the
PL
induced
a
drastic
enhancement
of
the
synthesis
of
the
cytokines
IL-Ââ6
and
IL-Ââ8
and
of
NGAL,
a
lipocalin
expressed
in
cells
of
the
chondrogenic
lineage.
These
events
were
controlled
by
the
p38
MAP
kinase
and
NF-ÂâÎșÎ
pathways.
The
pro-Ââinflammatory
effect
of
the
PL
was
a
transient
phenomenon.
In
fact,
after
an
initial
up
regulation,
we
observed
a
significant
reduction
of
the
NF-ÂâÎșÎ
activity
together
with
the
repression
of
the
inflammatory
enzyme
ciclooxygenase-Ââ2
(COX-Ââ2).
Moreover,
the
medium
of
chondrocytes
cultured
in
the
contemporary
presence
of
PL
and
IL-Ââ1α,
showed
a
significant
enhancement
of
the
chemoattractant
activity
versus
untreated
chondrocytes.
On
the
whole,
our
findings
support
the
concept
that
the
platelet
products
have
a
direct
beneficial
effect
on
articular
chondrocytes
and
at
the
same
time
could
drive
in
sequence
a
trans
A lymphofollicular microenvironment is required for pathological prion protein deposition in chronically inflamed tissues from scrapie-affected sheep
In sheep scrapie, pathological prion protein (PrPSc) deposition occurs in the lymphoreticular and central nervous systems. We investigated PrPSc distribution in scrapie- affected sheep showing simultaneous evidence of chronic lymphofollicular, lymphoproliferative/non-lymphofollicular,and/or granulomatous inflammations in their mammary gland, lung, and ileum. To do this, PrPSc detection was carried out via immunohistochemistry and Western Blotting techniques, as well as through inflammatory cell immunophenotyping. Expression studies of gene coding for biological factors modulating the hostâs inflammatory response were also carried out. We demonstrated that ectopic PrPSc deposition occurs exclusively in the context of lymphofollicular inflammatory sites, inside newly formed and well-organized lymphoid follicles harboring follicular dendritic cells. On the contrary, no PrPSc deposition was detected in granulomas, even when they were closely located to newly formed lymphoid follicles. A significantly more consistent expression of lymphotoxin α and ÎČ mRNA was detected in lymphofollicular inflammation compared to the other two types, with lymphotoxin α and ÎČ signaling new lymphoid folliclesâ formation and, likely, the occurrence of ectopic PrPSc deposition inside them. Our findings suggest that, in sheep co-affected by scrapie and chronic inflammatory conditions, only newly formed lymphoid follicles provide a suitable micro-environment that supports the scrapie agentâs replication in inflammatory sites, with an increased risk of prion shedding through body secretions/excretions.[...
Ovotransferrin and ovotransferrin receptor expression during chondrogenesis and endochondral bone formation in developing chick embryo
Kernel Methods for Document Filtering
This paper describes the algorithms implemented by the KerMIT consortium for its participation in the Trec 2002 Filtering track. The consortium submitted runs for the routing task using a linear SVM, for the batch task using the same SVM in combination with an innovation threshold-selection mechanism, and for the adaptive task using both a second-order perceptron and a combination of SVM and perceptron with uneven margin. Results seem to indicate that these algorithm performed relatively well on the extensive TREC benchmark
Cell proliferation, extracellular matrix mineralization, and ovotransferrin transient expression during in vitro differentiation of chick hypertrophic chondrocytes into osteoblast-like cells
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