Background and Objective: Development of human oral mucosa substitutes by tissue engineering may... more Background and Objective: Development of human oral mucosa substitutes by tissue engineering may provide new therapeutic tools for the management of periodontal diseases. In this study we evaluated a fibrin–agarose human oral mucosa substitute both in vitro and in vivo.Material and Methods: In vitro bioengineered oral mucosa substitutes were developed from irrelevant biopsy samples of human oral gingiva. In vivo evaluation of the constructed tissues was performed by implantation into athymic nude mice. The expression of several epithelial markers was assessed by microarray analysis and immunohistochemistry.Results: Bioengineered oral mucosa samples kept in vitro developed a multilayered epithelium that expressed several cytokeratins, including some markers of simple epithelia (cytokeratins 7, 8 and 18), along with markers of stratified epithelia (cytokeratins 5 and 13) and of cell proliferation (proliferating cell nuclear antigen). Bioengineered tissues grafted in vivo onto nude mice exhibited very good biointegration with the host, showing a cytokeratin expression pattern that was very similar to that of normal native oral mucosa controls. Histological analysis of the artificial tissues demonstrated that oral mucosa substitutes evaluated in vivo were structurally mature, showing some typical structures of human native oral mucosa such as rete ridges and chorial papillae, along with numerous blood vessels at the fibrin–agarose stromal substitute. These structures were absent in samples evaluated in vitro.Conclusion: The results indicate that this model of human oral mucosa, constructed using fibrin–agarose scaffolds, shows similarities to native oral mucosa controls and imply that bioengineered oral mucosa substitutes could eventually be used clinically.
The purpose of this study was to compare the effects of five different cryopreservation protocols... more The purpose of this study was to compare the effects of five different cryopreservation protocols on the histology of bioengineered tissues. Although several artificial tissues have been developed to the date by tissue engineering, classical histological analysis methods and techniques must be optimized for these new tissues with special properties. The results of this study showed that the use of volatile solutions (formaldehyde, glutaraldehyde, glacial acetic acid and acetone) was not able to prevent the formation of large ice crystals that, in turn, can alter the structure of the artificial tissues. However, preincubation of the tissues in different concentrations of a carbon hydrate (glucose, maltose or trehalose) resulted in a better preservation of the tissue structure. We conclude that the best protocol that allows for an efficient analysis of the bioengineered tissues with very few artifacts is preincubation of the tissues in 0.300M or 0.400M trehalose for 30 or 120 min prior to OCT (optimal cutting temperature) embedding and cryosectioning. For all those reasons, we recommend the use of a cryoprotective agent before OCT embedding of human artificial tissues.
Peripheral nerves are complex histological structures that can be affected by a variety of condit... more Peripheral nerves are complex histological structures that can be affected by a variety of conditions with different degree of axonal degeneration and demyelination. For the study of peripheral nerve regeneration in pathology and tissue engineering, it is necessary to evaluate the regeneration, remyelination and extracellular matrix reorganization of the neural tissue. Currently, different histochemical techniques must be used in parallel, and a correlation among their findings should be further performed. In this work, we describe a new histochemical method for myelin and collagen fibers based on luxol fast blue and picrosirius methods, for the evaluation of the morphology, the myelin sheath and the collagen fiber reorganization using a model of peripheral nerve regeneration. Whole brain, normal sciatic nerve and regenerating peripheral nerve samples were fixed in 10% neutral buffered formalin and paraffin-embedded, for the performance of the hematoxylin-eosin stain, the Luxol fast blue method and the new histochemical method for myelin and collagen. The results of this technique revealed that this new histochemical method allowed us to properly evaluate histological patterns, and simultaneously observe the histochemical reaction for myelin sheath and collagen fibers in normal tissue, and during the regeneration process. In conclusion, this new method combines morphological and histochemical properties that allowed us to determine with high accuracy the degree of remyelination and collagen fibers reorganization. For all these reasons, we hypothesize that this new histochemical method could be useful in pathology and tissue engineering.
This paper aims to study the anterior surface of the optic nerve in relation to its ability to su... more This paper aims to study the anterior surface of the optic nerve in relation to its ability to support a source of stress acting from the vitreous cavity. The intercellular junctions of the lining astrocytes mediated by cellular adhesion molecules (CAMs) may be the main targets for ionic stress.
In this work we performed a study of cytokeratin (CK) expression profiling on human artificial or... more In this work we performed a study of cytokeratin (CK) expression profiling on human artificial oral mucosa developed in vitro by tissue engineering at different stages of maturation (from immature to well-developed stages) at the protein and mRNA levels. Human artificial oral mucosa ...
The potentiality of adipose-derived stem cells (ASCs) cultured on 2D systems has been previously ... more The potentiality of adipose-derived stem cells (ASCs) cultured on 2D systems has been previously established. Nevertheless, very little is known so far about the differentiation potentiality of ASCs in 3D culture systems using biomaterials. In this work, we have evaluated the transdifferentiation capabilities of ASCs cultured within a novel fibrin-agarose biomaterial by histological analysis, histochemistry and immunofluorescence. Our results showed that 3D fibrin-agarose biomaterial is highly biocompatible and supports the transdifferentiation capabilities of ASCs to the osteogenic, chondrogenic, adipogenic, and neurogenic lineages.
Background and Objective: Development of human oral mucosa substitutes by tissue engineering may... more Background and Objective: Development of human oral mucosa substitutes by tissue engineering may provide new therapeutic tools for the management of periodontal diseases. In this study we evaluated a fibrin–agarose human oral mucosa substitute both in vitro and in vivo.Material and Methods: In vitro bioengineered oral mucosa substitutes were developed from irrelevant biopsy samples of human oral gingiva. In vivo evaluation of the constructed tissues was performed by implantation into athymic nude mice. The expression of several epithelial markers was assessed by microarray analysis and immunohistochemistry.Results: Bioengineered oral mucosa samples kept in vitro developed a multilayered epithelium that expressed several cytokeratins, including some markers of simple epithelia (cytokeratins 7, 8 and 18), along with markers of stratified epithelia (cytokeratins 5 and 13) and of cell proliferation (proliferating cell nuclear antigen). Bioengineered tissues grafted in vivo onto nude mice exhibited very good biointegration with the host, showing a cytokeratin expression pattern that was very similar to that of normal native oral mucosa controls. Histological analysis of the artificial tissues demonstrated that oral mucosa substitutes evaluated in vivo were structurally mature, showing some typical structures of human native oral mucosa such as rete ridges and chorial papillae, along with numerous blood vessels at the fibrin–agarose stromal substitute. These structures were absent in samples evaluated in vitro.Conclusion: The results indicate that this model of human oral mucosa, constructed using fibrin–agarose scaffolds, shows similarities to native oral mucosa controls and imply that bioengineered oral mucosa substitutes could eventually be used clinically.
The purpose of this study was to compare the effects of five different cryopreservation protocols... more The purpose of this study was to compare the effects of five different cryopreservation protocols on the histology of bioengineered tissues. Although several artificial tissues have been developed to the date by tissue engineering, classical histological analysis methods and techniques must be optimized for these new tissues with special properties. The results of this study showed that the use of volatile solutions (formaldehyde, glutaraldehyde, glacial acetic acid and acetone) was not able to prevent the formation of large ice crystals that, in turn, can alter the structure of the artificial tissues. However, preincubation of the tissues in different concentrations of a carbon hydrate (glucose, maltose or trehalose) resulted in a better preservation of the tissue structure. We conclude that the best protocol that allows for an efficient analysis of the bioengineered tissues with very few artifacts is preincubation of the tissues in 0.300M or 0.400M trehalose for 30 or 120 min prior to OCT (optimal cutting temperature) embedding and cryosectioning. For all those reasons, we recommend the use of a cryoprotective agent before OCT embedding of human artificial tissues.
Peripheral nerves are complex histological structures that can be affected by a variety of condit... more Peripheral nerves are complex histological structures that can be affected by a variety of conditions with different degree of axonal degeneration and demyelination. For the study of peripheral nerve regeneration in pathology and tissue engineering, it is necessary to evaluate the regeneration, remyelination and extracellular matrix reorganization of the neural tissue. Currently, different histochemical techniques must be used in parallel, and a correlation among their findings should be further performed. In this work, we describe a new histochemical method for myelin and collagen fibers based on luxol fast blue and picrosirius methods, for the evaluation of the morphology, the myelin sheath and the collagen fiber reorganization using a model of peripheral nerve regeneration. Whole brain, normal sciatic nerve and regenerating peripheral nerve samples were fixed in 10% neutral buffered formalin and paraffin-embedded, for the performance of the hematoxylin-eosin stain, the Luxol fast blue method and the new histochemical method for myelin and collagen. The results of this technique revealed that this new histochemical method allowed us to properly evaluate histological patterns, and simultaneously observe the histochemical reaction for myelin sheath and collagen fibers in normal tissue, and during the regeneration process. In conclusion, this new method combines morphological and histochemical properties that allowed us to determine with high accuracy the degree of remyelination and collagen fibers reorganization. For all these reasons, we hypothesize that this new histochemical method could be useful in pathology and tissue engineering.
This paper aims to study the anterior surface of the optic nerve in relation to its ability to su... more This paper aims to study the anterior surface of the optic nerve in relation to its ability to support a source of stress acting from the vitreous cavity. The intercellular junctions of the lining astrocytes mediated by cellular adhesion molecules (CAMs) may be the main targets for ionic stress.
In this work we performed a study of cytokeratin (CK) expression profiling on human artificial or... more In this work we performed a study of cytokeratin (CK) expression profiling on human artificial oral mucosa developed in vitro by tissue engineering at different stages of maturation (from immature to well-developed stages) at the protein and mRNA levels. Human artificial oral mucosa ...
The potentiality of adipose-derived stem cells (ASCs) cultured on 2D systems has been previously ... more The potentiality of adipose-derived stem cells (ASCs) cultured on 2D systems has been previously established. Nevertheless, very little is known so far about the differentiation potentiality of ASCs in 3D culture systems using biomaterials. In this work, we have evaluated the transdifferentiation capabilities of ASCs cultured within a novel fibrin-agarose biomaterial by histological analysis, histochemistry and immunofluorescence. Our results showed that 3D fibrin-agarose biomaterial is highly biocompatible and supports the transdifferentiation capabilities of ASCs to the osteogenic, chondrogenic, adipogenic, and neurogenic lineages.
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