scholarly journals TGF-beta 1 influences the relative development of the exocrine and endocrine pancreas in vitro

Development ◽  
1994 ◽  
Vol 120 (12) ◽  
pp. 3451-3462 ◽  
Author(s):  
F. Sanvito ◽  
P.L. Herrera ◽  
J. Huarte ◽  
A. Nichols ◽  
R. Montesano ◽  
...  
Keyword(s):  
Endocrine Cells ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Tgf Beta ◽  
Collagen Gels ◽  
Paracrine Factors ◽  
Fold Family ◽  
Acinar Tissue

Pancreatic rudiments from E12.5 mouse embryos undergo extensive development and differentiation when cultured in three-dimensional gels of extracellular matrix proteins for up to 12 days. Whereas collagen gels promote the formation of numerous exocrine acini and relatively small clusters of endocrine cells, in basement membrane (EHS) matrices the development of endocrine cells is dramatically favoured over that of acinar tissue. Buds embedded in a collagen gel contiguous to an EHS gel also fail to develop acini, suggesting the involvement of diffusible factor(s). Addition of cytokines to cultures of pancreatic buds in collagen gels modifies the relative proportions of the epithelial components of the gland. In the presence of EGF the proportion of the tissue occupied by ducts overrides that of acinar structures, whereas the endocrine portion of the tissue is not significantly modified. TGF-beta 1 partially mimicks the effect of EHS matrix in inhibiting the development of acinar tissue without decreasing the amount of ducts and mesenchyme; TGF-beta 1 also promotes the development of endocrine cells, in particular of insulin-containing beta cells and of cells expressing genes of the PP-fold family. These results show that cytokines can modulate the development of the pancreas and suggest a role for TGF-beta 1 in regulating the balance between the acinar and endocrine portions of the gland in vivo. More generally, they are compatible with the notion that, during organogenesis, cytokines act as paracrine factors responsible for the development and maintenance of appropriate proportions of different tissue constituents.

scholarly journals Epithelia suspended in collagen gels can lose polarity and express characteristics of migrating mesenchymal cells.

1982 ◽  
Vol 95 (1) ◽  
pp. 333-339 ◽  
Author(s):  
G Greenburg ◽  
E D Hay
Keyword(s):  
Epithelial Cells ◽  
Cell Polarity ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Mesenchymal Cells ◽  
Apical Surface ◽  
Collagen Gels ◽  
Mesenchymal Transformation

This study of epithelial-mesenchymal transformation and epithelial cell polarity in vitro reveals that environmental conditions can have a profound effect on the epithelial phenotype, cell shape, and polarity as expressed by the presence of apical and basal surfaces. A number of different adult and embryonic epithelia were suspended within native collagen gels. Under these conditions, cells elongate, detach from the explants, and migrate as individual cells within the three-dimensional lattice, a previously unknown property of well-differentiated epithelia. Epithelial cells from adult and embryonic anterior lens were studied in detail. Elongated cells derived from the apical surface develop pseudopodia and filopodia characteristic of migratory cells and acquire a morphology and ultrastructure virtually indistinguishable from that of mesenchymal cells in vivo. It is concluded from these experiments that the three-dimensional collagen gel can promote dissociation, migration, and acquisition of secretory organelles by differentiated epithelial cells, and can abolish the apical-basal cell polarity characteristic of the original epithelium.

scholarly journals The selective binding and transmigration of monocytes through the junctional complexes of human endothelium.

1988 ◽  
Vol 168 (5) ◽  
pp. 1865-1882 ◽  
Author(s):  
N A Pawlowski ◽  
G Kaplan ◽  
E Abraham ◽  
Z A Cohn
Keyword(s):  
Silver Staining ◽  
Umbilical Vein ◽  
Collagen Gel ◽  
Collagen Gels ◽  
Silver Stain ◽  
Term Survival ◽  
Topographical Distribution ◽  
Junctional Complexes

Human monocytes show a high affinity for vascular endothelium both in vitro and in vivo. To explore monocyte-endothelial interaction in greater detail, we have developed a new in vitro model for growth of human endothelial cells (EC). Human umbilical vein EC (HUVEC) cultured upon collagen gels form confluent monolayers of EC that bind silver at their intercellular border similar to cells in situ. Intercellular junctional structures, both adherens and tight junctions, were identified. In contrast, HUVEC grown on plastic surfaces did not stain with silver. The silver-staining characteristic of EC-collagen monolayers was reversible and related to their in vitro maturation and senescence. Silver staining of EC borders provided a grid by which the location of monocyte binding to the luminal surface of individual EC could be assessed. Using this technique, we found that monocytes preferentially bound to the margins of EC, in approximation to the silver-staining junctions. These results suggest that EC determinants recognized by monocytes occur in a unique topographical distribution on the apical face of EC. After binding, monocytes migrated through the EC monolayers at high basal rates. The lack of penetration of collagen gels in the absence of an EC monolayer suggested the generation of EC-specific chemotactic signal(s). Monocytes were observed to pass between EC without evidence of disruption of the monolayer. Silver stain remained present during all phases of migration, and under transmission electron microscopy, junctional complexes were found proximal to monocytes that had just completed their passage through the monolayer. After orientation to the basal surface of the EC monolayer, monocytes migrated randomly into the underlying collagen gel. Monocyte adherence, penetration, migration, and long term survival can be studied under these conditions.

Association between tension and orientation of periodontal ligament fibroblasts and exogenous collagen fibres in collagen gels in vitro

1982 ◽  
Vol 58 (1) ◽  
pp. 125-138
Author(s):  
C.G. Bellows ◽  
A.H. Melcher ◽  
J.E. Aubin
Keyword(s):  
Three Dimensional ◽  
Lower Surface ◽  
Cytochalasin D ◽  
Collagen Gels ◽  
Collagen Fibres ◽  
Periodontal Ligament Fibroblasts ◽  
The Relationship ◽  
Develop Tension

The relationship between the development of tension in sheets of fibroblasts and the orientation of these cells and collagen fibres in collagen gels was examined. Cell-containing, three-dimensional collagen gels were established in agarose-coated Epon dies measuring 10 mm X 4 mm X 4 mm, to which pieces of demineralized tooth and bone had been attached at opposite ends. Contraction of the gel into an opaque structure suspended between the two particles occurred over 24 h and resulted in concave upper and lateral surfaces and a flat to slightly concave lower surface. Initial orientation of the fibres along the tooth-bone axis was followed by similar orientation of the cells. Gels cast without cells exhibited no change in dimensions. Release of the tooth particle after 12 or 24 h of incubation led to shortening of the contracted gels 5 min following release. This shortening was significantly greater (P less than 0.001) than that of uncontracted or slightly contracted gels (1 h and 3 h incubation). Gels attached at one end only compacted around the site of attachment but did not show orientation of cells or fibres. Gels containing colcemid or cytochalasin D were only slightly compacted and did not develop tension. Collagen fibres, but not cell in colcemid-containing gels, showed some alignment; neither were aligned in the presence of cytochalasin D. These data suggest that both microtubules and microfilaments are necessary for alignment of cells and the establishment of tension between two points of attachment in collagen gels. Furthermore, they lend support to our previously advanced hypothesis that the development of tension between two points can result in the orientation of the cells along an axis connecting the points of attachment. This could provide a mechanism for the development of oriented fibre systems in vivo.

Prolactin effects on ion transport across cultured mouse mammary epithelium

1981 ◽  
Vol 240 (3) ◽  
pp. C110-C115 ◽  
Author(s):  
C. A. Bisbee
Keyword(s):  
Cell Cultures ◽  
Short Circuit ◽  
Collagen Gel ◽  
Mammary Epithelium ◽  
Short Circuit Current ◽  
Sodium Absorption ◽  
Collagen Gels ◽  
Mouse Mammary Epithelium

Prolactin is a known osmoregulatory hormone in lower vertebrates, and recent evidence indicates that this hormone modulates ionic concentrations in milk. In an ultrastructurally and biochemically differentiated primary cell culture system in which mouse mammary epithelium is maintained on floating collagen gels, prolactin causes an increase in short-circuit current (Isc) of monolayers of cells derived from midpregnant (24.6 to 48.0 microA . cm-2) and lactating (10.4 to 16.1 microA . cm-2) glands. Transepithelial potential differences (basal side ground) average about -12 mV and are similar to those seen in vivo. Prelactating mammary epithelial cell cultures have transepithelial resistances ranging from 374 omega . cm2 (prolactin present) to 507 omega . cm2 (prolactin absent), and lactating cell cultures have resistances averaging almost 1,000 omega . cm2. Prolactin effects require at most one day of culture maintenance in prolactin-containing medium, and the effects are not due to known contamination of prolactin preparations with arginine vasopressin or growth hormone. Medium concentrations of prolactin as low as 1 ng/ml can elicit these effects. In prelactating cell cultures not treated with prolactin, the Isc is equal to the rate of sodium absorption. Prolactin increases sodium absorption fourfold but increases Isc only twofold. Clearly, prolactin induces other active transport; neither potassium nor chloride movements can account for this additional transport. Resistance values, current-voltage plots, and permeability coefficients indicate that in vitro mammary epithelium is a moderately “tight” tissue. Comparisons with intact glands indicate that in vitro mammary epithelium closely resembles its in vivo counterpart. Floating collagen gel cultures appear suitable for elucidating transport properties in cellularly heterogeneous and structurally complex mammalian tissues.

Effect of shear stress on microvessel network formation of endothelial cells with in vitro three-dimensional model

2004 ◽  
Vol 287 (3) ◽  
pp. H994-H1002 ◽  
Author(s):  
Akinori Ueda ◽  
Masaki Koga ◽  
Mariko Ikeda ◽  
Susumu Kudo ◽  
Kazuo Tanishita
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Network Formation ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Flow Chamber ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Collagen Gels

Shear stress stimulus is expected to enhance angiogenesis, the formation of microvessels. We determined the effect of shear stress stimulus on three-dimensional microvessel formation in vitro. Bovine pulmonary microvascular endothelial cells were seeded onto collagen gels with basic fibroblast growth factor to make a microvessel formation model. We observed this model in detail using phase-contrast microscopy, confocal laser scanning microscopy, and electron microscopy. The results show that cells invaded the collagen gel and reconstructed the tubular structures, containing a clearly defined lumen consisting of multiple cells. The model was placed in a parallel-plate flow chamber. A laminar shear stress of 0.3 Pa was applied to the surfaces of the cells for 48 h. Promotion of microvessel network formation was detectable after ∼10 h in the flow chamber. After 48 h, the length of networks exposed to shear stress was 6.17 (±0.59) times longer than at the initial state, whereas the length of networks not exposed to shear stress was only 3.30 (±0.41) times longer. The number of bifurcations and endpoints increased for networks exposed to shear stress, whereas the number of bifurcations alone increased for networks not exposed to shear stress. These results demonstrate that shear stress applied to the surfaces of endothelial cells on collagen gel promotes the growth of microvessel network formation in the gel and expands the network because of repeated bifurcation and elongation.

scholarly journals Three-Dimensional In Vitro Staphylococcus aureus Abscess Communities Display Antibiotic Tolerance and Protection from Neutrophil Clearance

2020 ◽  
Vol 88 (11) ◽  
Author(s):  
Marloes I. Hofstee ◽  
Martijn Riool ◽  
Igors Terjajevs ◽  
Keith Thompson ◽  
Martin J. Stoddart ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Cells ◽  
Early Stage ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Maximum Size ◽  
Human Neutrophils ◽  
Content Type

ABSTRACT Staphylococcus aureus is a prominent human pathogen in bone and soft-tissue infections. Pathophysiology involves abscess formation, which consists of central staphylococcal abscess communities (SACs), surrounded by a fibrin pseudocapsule and infiltrating immune cells. Protection against the ingress of immune cells such as neutrophils, or tolerance to antibiotics, remains largely unknown for SACs and is limited by the lack of availability of in vitro models. We describe a three-dimensional in vitro model of SACs grown in a human plasma-supplemented collagen gel. The in vitro SACs reached their maximum size by 24 h and elaborated a fibrin pseudocapsule, as confirmed by electron and immunofluorescence microscopy. The in vitro SACs tolerated 100× the MIC of gentamicin alone and in combination with rifampin, while planktonic controls and mechanically dispersed SACs were efficiently killed. To simulate a host response, SACs were exposed to differentiated PLB-985 neutrophil-like (dPLB) cells and to primary human neutrophils at an early stage of SAC formation or after maturation at 24 h. Both cell types were unable to clear mature in vitro SACs, but dPLB cells prevented SAC growth upon early exposure before pseudocapsule maturation. Neutrophil exposure after plasmin pretreatment of the SACs resulted in a significant decrease in the number of bacteria within the SACs. The in vitro SAC model mimics key in vivo features, offers a new tool to study host-pathogen interactions and drug efficacy assessment, and has revealed the functionality of the S. aureus pseudocapsule in protecting the bacteria from host phagocytic responses and antibiotics.

Antibacterial Wound Healing Gels from Oligochitosan Salts

2012 ◽  
Vol 506 ◽  
pp. 31-34
Author(s):  
W. Janvikul ◽  
P. Ngamviriyavong ◽  
P. Uppanun ◽  
P. Tanjak ◽  
N. Sangjun
Keyword(s):  
Staphylococcus Epidermidis ◽  
Wound Closure ◽  
Collagen Gel ◽  
Antibacterial Activities ◽  
Dermal Fibroblasts ◽  
Collagen Gels ◽  
Collagen Gel Matrix ◽  
Growth Of Bacteria

Oligochitosan salt-based antibacterial wound gels were developed and evaluated in both in vitro and in vivo models. The antibacterial activities of the oligochitosan salts and the wound gels were investigated against Staphylococcus epidermidis RP625 and Escherichia coli ATCC 11775. The minimum inhibitory concentrations (MIC) of the oligochitosan salts were found in the range of 16-256 μg/mL. The wound gels demonstrated their in vitro activities on inhibiting the growth of bacteria. The 3-D collagen gel matrix containing human dermal fibroblasts cultured with each test gel was used as an in vitro model for the examination of cell proliferation and secretion of interleukin-8 (IL-8). The gels appeared to promote the proliferation and formation of cellular process of the fibroblasts in the 3-D collagen gels and stimulate the fibroblasts to produce more IL-8. In the in vivo model, it was noted that the gels could accelerate the wound closure process. The wounds were completely closed within 14 days.

scholarly journals Genetic regulation of murine pituitary development

2015 ◽  
Vol 54 (2) ◽  
pp. R55-R73 ◽  
Author(s):  
Karine Rizzoti
Keyword(s):  
Endocrine Cells ◽  
Molecular Mechanisms ◽  
Genetic Regulation ◽  
Three Dimensional ◽  
Significant Progress ◽  
Pituitary Development ◽  
Tumour Formation ◽  
Ventral Diencephalon

Significant progress has been made recently in unravelling the embryonic events leading to pituitary morphogenesis, bothin vivoandin vitro. This includes dissection of the molecular mechanisms controlling patterning of the ventral diencephalon that regulate formation of the pituitary anlagen or Rathke's pouch. There is also a better characterisation of processes that underlie maintenance of pituitary progenitors, specification of endocrine lineages and the three-dimensional organisation of newly differentiated endocrine cells. Furthermore, a population of adult pituitary stem cells (SCs), originating from embryonic progenitors, have been described and shown to have not only regenerative potential, but also the capacity to induce tumour formation. Finally, the successful recapitulationin vitroof embryonic events leading to generation of endocrine cells from embryonic SCs, and their subsequent transplantation, represents exciting advances towards the use of regenerative medicine to treat endocrine deficits. In this review, an up-to-date description of pituitary morphogenesis will be provided and discussed with particular reference to pituitary SC studies.

scholarly journals In vitro rapid organization of endothelial cells into capillary-like networks is promoted by collagen matrices.

1983 ◽  
Vol 97 (5) ◽  
pp. 1648-1652 ◽  
Author(s):  
R Montesano ◽  
L Orci ◽  
P Vassalli
Keyword(s):  
Endothelial Cells ◽  
Three Dimensional ◽  
Collagen Matrix ◽  
Collagen Gels ◽  
Collagen Matrices ◽  
Narrow Lumen ◽  
Capillary Endothelial Cells ◽  
Vitro Model

We have studied the behavior of cloned capillary endothelial cells grown inside a three dimensional collagen matrix. Cell monolayers established on the surface of collagen gels were covered with a second layer of collagen. This induced the monolayers of endothelial cells to reorganize into a network of branching and anastomosing capillary-like tubes. As seen by electron microscopy, the tubes were formed by at least two cells (in transverse sections) delimiting a narrow lumen. In addition, distinct basal lamina material was present between the abluminal face of the endothelial cells and the collagen matrix. These results showed that capillary endothelial cells have the capacity to form vessel-like structures with well-oriented cell polarity in vitro. They also suggest that an appropriate topological relationship of endothelial cells with collagen matrices, similar to that occurring in vivo, has an inducive role on the expression of this potential. This culture system provides a simple in vitro model for studying the factors involved in the formation of new blood vessels (angiogenesis).

scholarly journals Murine spleen stromal cell line SPY3-2 maintains long-term hematopoiesis in vitro

Blood ◽  
1995 ◽  
Vol 85 (11) ◽  
pp. 3107-3116 ◽  
Author(s):  
J Tsuchiyama ◽  
M Mori ◽  
S Okada
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Stromal Cell ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Mouse Spleen ◽  
Hematopoietic Organ

The hematopoietic microenvironment (HIM) of mouse spleen predominantly induces the differentiation of hematopoietic progenitors into erythroid lineage in vivo. However, the mechanisms of this phenomenon have not been fully explored because of the lack of an adequate in vitro system mimicking the spleen hematopoiesis. To reconstruct the HIM of mouse spleen in vitro, we established spleen stromal cell lines from a three-dimensional (3D) spleen primary culture in collagen gel matrix. Of these, SPY3–2 cells were negative for preadipocytic and endothelial markers, had a fibroblastoid morphology, and were not converted to adipocytes in the presence of 1 mumol/L hydrocortisone. They supported the maintenance and multilineal differentiation of hematopoietic progenitor cells for more than 8 weeks in vitro. The differentiated hematopoietic cells in the coculture medium were predominantly monocytes rather than granulocytes. Furthermore, erythropoiesis was predominantly induced in the presence of 2 U/mL erythropoietin and continued for more than 12 weeks. The number of burst-forming units-erythroid (BFU-E) was increased 10 times after 3 weeks of coculture, which was followed by pronounced production of erythroid cells in the coculture after week 4. SPY3–2 expressed high levels of c-kit ligand and low levels of granulocyte macrophage colony-stimulating factor and interleukin-3, and these molecules were all involved in this long-term erythropoiesis. Thus, the clonal SPY3–2 cell line will provide a novel HIM in vitro analogous to that of mouse spleen in vivo. These results suggest that 3D collagen gel culture may facilitate the establishment of functioning stromal cell lines of hematopoietic organ.

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