Cultivo de células de cartílago nasal humano / Culure of human nasal cartilage cells

La producción de cartílago in vitro por bioingeniería de tejidos tienen un enorme potencial terapéutico. Sin embargo, en Venezuela aún no se ha desarrollado esta tecnología, por tanto en nuestro laboratorio se están desarrollando proyectos dirigidos a conocer aspectos involucrados en la biología de los condrocitos, así como también de los tipos de matrices a utilizar como sustrato para su cultivo. En este trabajo se aislaron condrocitos de cartílago nasal humano obtenidos de cirugías estéticas. Las células cultivadas sobre plástico a altas densidades crecen en monocapa, mostrando una morfología poliédrica característica hasta el segundo pasaje; en subcultivos sucesivos estas células muestran cambios morfológicos observándose células fusiformes, indicando un proceso de desdiferenciación. Cuando las células son incluidas en una matriz de colágeno tipo I la mayoría mantiene su morfología esférica típica y sintetizan componentes de matriz característicos como proteoglicanos y colágeno tipo II, marcadores de estabilidad fenotípica, factor importante para el desarrollo de neotejidos

The in vitro production of cartilage bu tissue bioengineered has an enormous therapeutic potential. However, this technology has not been developed in Venezuela, so, in our laboratory several projects related to biological aspects of chondrocytes and the best matrixial support for their culture are under study. In this work we have isolated chondrocytes from human nasal samples obtained from plastic surgery and culture of cells on plastic dishes at high densities. Initially the cells grew up as a monolayer of poliedric cells, and after the second passage this shape was modified, in successive subcultures there cells show spindle cell morphological changes observed, indicating a dedifferentiation process. When cells are embedded in a matrix of collagen type I most keep their spherical morphology typical characteristic matrix components synthesized as proteoglycans and collagen type II markers, phenotypic stability, an important factor for the development of new tissues

Aplicación clínica del aloinjerto de matriz dérmica acelular en cirugía plástica periodontal* / Clinical application of a cellular dermal matrix allograft in periodontal plastic surgery

Se han indicado diferentes procedimientos quirúrgicos para la preservación y aumento del reborde alveolar, así como para el tratamiento de recesiones gingivales e incremento de la amplitud de la encía adherida, alrededor de dientes naturales e implantes. Cuando se utilizan injertos autógenos en estas intervenciones se evidencian algunas desventajas que incluyen la inconformidad asociada con un sitio quirúrgico adicional y la disponibilidad limitada de tejido donante. Recientemente, se utilizan aloinjertos de matriz dérmica acelular como sustitutos de los injertos autógenos en cirugía plástica periodontal. La matriz dérmica es un aloinjerto libre de células obtenido de la piel humana, bioestructuralmente compuesto por membrana basal y matriz extracelular que actúa como una matriz que permite la neovascularización, y proliferación de fibroblastos y células epiteliales En esta serie de casos, se presentan tres aplicaciones quirúrgicas de la matriz dérmica: cubrimiento de recesiones gingivales, manejo de dehiscencias sobre implantes y aumento de reborde alveolar(AU)

Several surgical procedures have been indicated for the preservation and increase of the alveolar ridge, and for the treatment of gingival recessions so to increase the width of attached gingiva around natural teeth or implants. The disadvantages of harvesting autogenous grafts on these procedures lie in the postoperative discomfort associated with an extra surgical site, as well as the limitation of available donor tissues. Recently, an acellular dermal matrix allograft has been approved as substitutes for autogenous grafts in periodontal plastic surgery. Dermal matrix allograft are free cells obtained from human skin, bioestructuraly formed by basement membrane and extracellular matrix that act as a matrix that allow the revascularization and proliferation of fibroblasts and epithelial cells. In this series case, we present three surgical applications of the dermal matrix: coverage of gingival recessions, management of implant dehiscence and alveolar ridge augmentation(AU)

Effect of cell surface sialic acid and their linkages on adhesion of mammary carcinoma cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of cell surface sialic acid and its linkage on the cell-cell and cell-matrix adhesion of mammary carcinoma cells MD-MB-435.</p><p><b>METHODS</b>MD-MB-435 cells were sense-transfected with ST6Gal I cDNA or antisense-transfected with part of the ST6Gal I sequence inserted in pcDNA 3.1 vector, with mock transfection with pcDNA3.1 vector as the control. The cell surface alpha2, 6-linked sialylation was determined by fluorescence-activated cell sorting (FACS) using lectin SNA (Sambucus nigra agglutinin specific to alpha2, 6-linked sialic acid on N-linked glycoprotein). A significantly increased alpha2, 6-sialylation subclone in sense-transfectants and a decreased alpha2, 6-sialylation subclone in antisense-transfectants were selected for further examination of cell-cell and cell-matrix (collagen IV) adhesion. The transfectants were also treated with sialidase to compare the capacity of cell adhesion affected by cell surface sialylation.</p><p><b>RESULTS</b>Sense-transfection subclone showed a reduced cell-cell aggregation but enhanced cell-matrix adhesion. In contrast, the antisense-transfection subclone exhibited increased cell-cell aggregation and decreased cell-matrix adhesion. After treatment with sialidase, the cell-matrix adhesion of all the transfectants and the parental MDA-MB-435 cells were significantly reduced to the level of 31%-57% of untreated cells.</p><p><b>CONCLUSION</b>Cell surface sialic acid and alpha2, 6-linked sialylation play an important role in cell-cell and cell-matrix adhesion of mammary carcinoma cell MDA-MB-435.</p>

Cell-matrix adhesions of soft tissue cells around dental implants / 대한치과보철학회지

The importance of soft tissue response to implant abutments has become one of the major issues in current implant dentistry. To date, numerous studies have emphasized on maintaining connective tissue barriers in quantity, as well as in quality for the long term success of dental implants. The cells mainly consisting the soft tissue around dental implants are fibroblasts and epithelial cells. The mechanism of the fibroblasts'adhesions to certain substrata can be explained by the 'focal adhesion'theory. On the other hand, epithelial cells adhere to the substratum via hemidesmosomes. The typical integrin-mediated adhesions of cells to certain matrix are called 'cell-matrix adhsions'. The focal adhesion complex of fibroblasts, in relation to the cell-matrix adhsions, consists of the extracellular matrix(ECM) such as fibronectin, the transmembrane proteins such as integrins, the intracellular cytoplasmic proteins such as vinculin, talin, and more, and the cytoskeletal structures such as filamentous actin and microtubules. The mechanosensory function of integrins and focal adhesion complexes are considered to play a major role in the cells'adhesion, migration, proliferation, differentiation, division, and even apoptosis. The '3-D matrix adhesions'defined by Cukierman et al. makes a promising future for the verification of the actual process of the cell-matrix adhesions in vivo and can be applied to the field of implant dentistry in relation to obtaining strong soft tissue attachment to the implant abutments.

Cell-matrix adhesions of soft tissue cells around dental implants / 대한치과보철학회지

The importance of soft tissue response to implant abutments has become one of the major issues in current implant dentistry. To date, numerous studies have emphasized on maintaining connective tissue barriers in quantity, as well as in quality for the long term success of dental implants. The cells mainly consisting the soft tissue around dental implants are fibroblasts and epithelial cells. The mechanism of the fibroblasts'adhesions to certain substrata can be explained by the 'focal adhesion'theory. On the other hand, epithelial cells adhere to the substratum via hemidesmosomes. The typical integrin-mediated adhesions of cells to certain matrix are called 'cell-matrix adhsions'. The focal adhesion complex of fibroblasts, in relation to the cell-matrix adhsions, consists of the extracellular matrix(ECM) such as fibronectin, the transmembrane proteins such as integrins, the intracellular cytoplasmic proteins such as vinculin, talin, and more, and the cytoskeletal structures such as filamentous actin and microtubules. The mechanosensory function of integrins and focal adhesion complexes are considered to play a major role in the cells'adhesion, migration, proliferation, differentiation, division, and even apoptosis. The '3-D matrix adhesions'defined by Cukierman et al. makes a promising future for the verification of the actual process of the cell-matrix adhesions in vivo and can be applied to the field of implant dentistry in relation to obtaining strong soft tissue attachment to the implant abutments.

Cell attachment of periodontal ligament cells on commercially pure titanium at the early stage / 华中科技大学学报（医学）（英德文版）

In order to study the character of periodontal ligament cells (PDLCs) attaching on commercially pure titanium (cpTi) by morphology and metrology on the early stage (24 h), 1 x 10(5)/ml PDLCs in 2 ml culture medium were seeded on cpTi discs fixed in 24-well culture plates. Morphology of cell attachment was observed by contrast phase microscope, scanning electron microscope (SEM) and fluroscence microscopy. Cell adhesion was analyzed by MTT at 0.5, 1, 2, 4 h respectively. PDLCs could attach and spread on cpTi discs. SEM showed that PDLCs had pseudopod-like protuberance. PDLCs showed different attaching phases and reached saturation in cell number at 2 h. It was concluded that PDLCs had good biocompatibility with cpTi, and showed a regular and dynamic pattern in the process of attaching to cpTi.

Cell attachment of periodontal ligament cells on commercially pure titanium at the early stage / 华中科技大学学报（医学）（英德文版）

In order to study the character of periodontal ligament cells (PDLCs) attaching on commercially pure titanium (cpTi) by morphology and metrology on the early stage (24 h), 1 x 10(5)/ml PDLCs in 2 ml culture medium were seeded on cpTi discs fixed in 24-well culture plates. Morphology of cell attachment was observed by contrast phase microscope, scanning electron microscope (SEM) and fluroscence microscopy. Cell adhesion was analyzed by MTT at 0.5, 1, 2, 4 h respectively. PDLCs could attach and spread on cpTi discs. SEM showed that PDLCs had pseudopod-like protuberance. PDLCs showed different attaching phases and reached saturation in cell number at 2 h. It was concluded that PDLCs had good biocompatibility with cpTi, and showed a regular and dynamic pattern in the process of attaching to cpTi.

Regulation of Rho family GTPases by cell-cell and cell-matrix adhesion

Integrins and cadherins are transmembrane adhesion receptors that are necessary for cells to interact with the extracellular matrix or adjacent cells, respectively. Integrins and cadherins initiate signaling pathways that modulate the activity of Rho family GTPases. The Rho proteins Cdc42, Rac1, and RhoA regulate the actin cytoskeleton. Cdc42 and Rac1 are primarily involved in the formation of protrusive structures, while RhoA generates myosin-based contractility. Here we examine the differential regulation of RhoA, Cdc42, and Rac1 by integrin and cadherin signaling. Integrin and cadherin signaling leads to a decrease in RhoA activity and activation of Cdc42 and Rac1. When the normal RhoA suppression is antagonized or RhoA signaling is increased, cells exhibited impaired spreading on the matrix protein fibronectin and decreased cell-cell adhesion. Spreading on fibronectin and the formation of cell-cell adhesions is decreased in cells expressing dominant negative forms of Cdc42 or Rac1. These data demonstrate that integrins and cadherins regulate Rho proteins in a comparable manner and lead us to speculate that these changes in Rho protein activity participate in a feedback mechanism that promotes further cell-matrix or cell-cell interaction, respectively