237 research outputs found
Immunological Compatibility Status of Placenta-Derived Stem Cells is Mediated by Scaffold 3D Structure
Placenta-derived amniotic epithelial cells (AECs), a great cell source for tissue engineering and stem cell therapy, are immunologically inert in their native state; however, immunological changes in these cells after culture and differentiation have challenged their applications. The aim of this study was to investigate the effect of 2D and 3D scaffolds on human lymphocyte antigens (HLA) expression by AECs. The effect of different preparation parameters including pre-freezing time and temperature was evaluated on 3D chitosan–gelatine scaffolds properties. Evaluation of MHC class I, HLA-DR and HLA-G expression in AECs after 7 d culture on 2D bed and 3D scaffold of chitosan–gelatine showed that culture of AECs on the 2D substrate up-regulated MHC class I and HLA-DR protein markers on AECs surface and down-regulated HLA-G protein. In contrast, 3D scaffold did not increase protein expression of MHC class I and HLA-DR. Moreover, HLA-G protein expression remained unchanged in 3D culture. These results confirm that 3D scaffold can remain AECs in their native immunological state and modification of physical properties of the scaffold is a key regulator of immunological markers at the gene and protein expression levels; a strategy which circumvents rejection challenge of amniotic stem cells to be translated into the clinic
A micro-macro evaluation of the vertebral bony endplate permeability based on computational fluid dynamics
The intrinsic permeability is an important parameter that
describes the resistance
of a porous structure
to fluid flo
w. It
has a key role in poroelastic finite element models of spinal
segments, especially at the
vertebral endplate, i.e. the
interface
between intervertebral disc and vertebra. In the understanding
of the properties of the complex endplate system, an expli
cit
evaluation for permeability of subchondral bone is missing.
Thus, a
new method
wa
s
proposed to evaluate the intrinsic
permeability of the bony endplate.
CT
-
based reconstruction
s
of the bony endplate from a lumbar vertebra were analyzed
using computational fluid dynamics
, and
the i
ntrinsic
permeability and porosity
of the structure
were calculated.
Results showed that
the
permeability
did
not depend on
the
fluid flow direction,
and was statistically similar for both the
superior and inferior endplates
. Permeability values varied
within the range of trabecular bone, while porosity
values
w
ere
lower than trabecular bone characteristic values.
Finally,
i
ntrins
ic permeability correlated well with porosity
through the
Kozeny
-
Karman model, which
offer
s
perspectives for
parametric studies involving degenerative or age
-
related
changes at the disc
-
bone interface.Postprint (published version
Inhibition of Inflammation, Suppression of Matrix Metalloproteinases, Induction of Neurogenesis, and Antioxidant Property Make Bryostatin-1 a Therapeutic Choice for Multiple Sclerosis
Multiple sclerosis (MS) is a neurodegenerative disease characterized by inflammation and myelin damage. Pro-inflammatory cytokines, oxidative stress, high level of matrix metalloproteinases (MMPs) activity and blood–brain barrier (BBB) damage, immune-mediated destruction of myelin and neuron loss are involved in the pathogenesis of MS. The currently approved treatments for MS include injectable drugs (interferon-β and glatiramer acetate), oral drugs (fingolimod), and monoclonal antibodies (natalizumab). The mentioned therapeutic choices are mostly focused on the inhibition of inflammation. Therefore, the search for a multi-target therapeutic choice remains unchallenged. It seems that a drug with anti-inflammatory, oxidative stress inhibitory, reduction of MMPs activity, and neurogenesis stimulatory properties may be effective for treatment of MS. In this regard, Bryostatin-1 as a macrolide and marine natural product has been selected as a therapeutic choice. Studies indicate that Bryostatin-1 has anti-inflammatory and antioxidant properties and decreases MMPs level and BBB damage. Furthermore, Bryostatin-1 has a neuroprotective effect and promotes neurogenesis and differentiation of oligodendrocyte progenitor stem cells as a critical step for remyelination/myelogenesis. Based on these properties, we hypothesized here that Bryostatin-1 is an effective treatment in MS
Gait changes precede overt arthritis and strongly correlate with symptoms and histopathological events in pristane-induced arthritis
Endothelial Extracellular Vesicles—Promises and Challenges
Extracellular vesicles, including exosomes, microparticles, and apoptotic bodies, are phospholipid bilayer-enclosed vesicles that have once been considered as cell debris lacking biological functions. However, they have recently gained immense interest in the scientific community due to their role in intercellular communication, immunity, tissue regeneration as well as in the onset, and progression of various pathologic conditions. Extracellular vesicles of endothelial origin have been found to play a versatile role in the human body, since they are on the one hand known to contribute to cardiovascular diseases, but on the other hand have also been reported to promote endothelial cell survival. Hence, endothelial extracellular vesicles hold promising therapeutic potential to be used as a new tool to detect as well as treat a great number of diseases. This calls for clinically approved, standardized, and efficient isolation and characterization protocols to harvest and purify endothelial extracellular vesicles. However, such methods and techniques to fulfill stringent requirements for clinical trials have yet to be developed or are not harmonized internationally. In this review, recent advances and challenges in the field of endothelial extracellular vesicle research are discussed and current problems and limitations regarding isolation and characterization are pointed out
Expression, purification and in vitro biological activity from human recombinant BMP-2 produced by a novel approach
Bone morphogenetic proteins have promoted great
biomedical interest due to their ability in inducing
new bone formation when used as powerful
osteoinductive components of several late-stage
bone grafting products. Recombinant human bone
morphogenetic protein-2 (rhBMP-2) is obtained from
mammalian cell expressing systems in low amounts
or from bacteria inclusion bodies after timeconsuming
refolding methods. Thus, there is a need
to establish novel approaches for producing rhBMP-2
in high yields by simple and cheap procedures.Portuguese Foundation for Science and Technolog
y, FCT (PhD Grant to PC
Bessa
, SFRH/BD/17049/2004). This work was also partially supported
by the European STREP HIPPOCRATES (NMP3
-
CT
-
2003
-
505758) and carried out under the scope of European
NoE
EXPERTISSUES (NMP3
-
CT
-
2004
-
500283).info:eu-repo/semantics/publishedVersio
Engineering Blood and Lymphatic Microvascular Networks in Fibrin Matrices
Vascular network engineering is essential for nutrient delivery to tissue-engineered constructs and, consequently, their survival. In addition, the functionality of tissues also depends on tissue drainage and immune cell accessibility, which are the main functions of the lymphatic system. Engineering both the blood and lymphatic microvasculature would advance the survival and functionality of tissue-engineered constructs. The aim of this study was to isolate pure populations of lymphatic endothelial cells (LEC) and blood vascular endothelial cells (BEC) from human dermal microvascular endothelial cells and to study their network formation in our previously described coculture model with adipose-derived stromal cells (ASC) in fibrin scaffolds. We could follow the network development over a period of 4 weeks by fluorescently labeling the cells. We show that LEC and BEC form separate networks, which are morphologically distinguishable and sustainable over several weeks. In addition, lymphatic network development was dependent on vascular endothelial growth factor (VEGF)-C, resulting in denser networks with increasing VEGF-C concentration. Finally, we confirm the necessity of cell–cell contact between endothelial cells and ASC for the formation of both blood and lymphatic microvascular networks. This model represents a valuable platform for in vitro drug testing and for the future in vivo studies on lymphatic and blood microvascularization
Human amniotic membrane as newly identifed source of amniotic fuid pulmonary surfactant
Pulmonary surfactant (PS) reduces surface tension at the air-liquid interface in the alveolar epithelium of the lung, which is required for breathing and for the pulmonary maturity of the developing foetus. However, the origin of PS had never been thoroughly investigated, although it was assumed to be secreted from the foetal developing lung. Human amniotic membrane (hAM), particularly its epithelial cell layer, composes the amniotic sac enclosing the amniotic fuid. In this study, we therefore aimed to investigate a potential contribution of the cellular components of the hAM to pulmonary surfactant found in amniotic fuid. We identifed that cells within the native membrane contain lamellar bodies and express all four surfactant proteins as well as ABCA3. Lipidomic profling by nanoESI – MS/MS revealed the presence of the essential lipid species as found in PS. Also, the biophysical activity of conditioned cell culture supernatant obtained from hAM was tested with captive bubble surfactometry. hAM supernatant showed the ability to reduce surface tension, similar to human PS obtained from bronchoalveolar lavage. This means that hAM produces the essential PS-associated components and can therefore contribute as second potential source of PS in amniotic fuid aside from the foetal lung
A novel approach for the production of human recombinant BMP-2 for bone tissue engineering applications
Bone tissue engineering has been an increasing field of research during the last years. The ideal approach for a regenerative application would consist in
the use of cells from the patient, scaffolding materials and differentiation growth factors. Bone morphogenetic protein-2 (BMP-2) is one such growth factors
with a strong ability to induce new bone and cartilage formation and has been used as a powerful osteoinductive component of several late-stage tissue
engineering products for bone grafting. In this work, we aimed at obtaining high yields of human recombinant BMP-2 in a stable, pure and biologically active
form by use of a new bacteria expression system that circumvents the disadvantages of conventional recombinant protein preparation methods and to
perform a study of the stability conditions and the functionality of these peptides in vitro in human mesenchymal stem cells and C2C12 murine cell line.info:eu-repo/semantics/publishedVersio
- …