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Tissue engineering and regenerative medicine -where do we stand?

Horch RE, Kneser U, Polykandriotis E, Schmidt VJ, Sun J, Arkudas A - J. Cell. Mol. Med. (2012)

Bottom Line: As a typical example in translational medicine, the discovery of a new type of cells called Telocytes that have been described in many organs and have been detected by electron microscopy opens another gate to RM.This article is intended to give an overview over some of the most recent developments and possible applications in RM through the perspective of TE achievements and cellular research.The synthesis of TE with innovative methods of molecular biology and stem-cell technology appears to be very promising.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic and Hand Surgery And Laboratory for Tissue Engineering and Regenerative Medicine, Friedrich Alexander University Erlangen-Nuernberg, Erlangen, Germany. raymund.horch@uk-erlangen.de

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Corrosion Cast of an axial neovascular assembly, in vivo vascular construct, 2 weeks after vascular induction. Left: Overview of a nascent capillary network. Middle: sprouting angiogenic event. A new capillary sprout emerging from the parent vessel by endothelial pericytic proliferation Right: intussusceptive angiogenic events. The parent vessel is divided into two distinct new vessels for the purpose of vascular growth or remodelling.
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fig03: Corrosion Cast of an axial neovascular assembly, in vivo vascular construct, 2 weeks after vascular induction. Left: Overview of a nascent capillary network. Middle: sprouting angiogenic event. A new capillary sprout emerging from the parent vessel by endothelial pericytic proliferation Right: intussusceptive angiogenic events. The parent vessel is divided into two distinct new vessels for the purpose of vascular growth or remodelling.

Mentions: The clinical scenario encompasses a number of difficult problems to solve as radiation therapy has become one of the main treatment options within the concept of multimodal tumour therapy. Following irradiation, the recipient site for any kind of tissue transfer lacks a normal vascularization potential. Neovascularization cannot easily appear from irradiated wound beds, and makes the common approach of transplanting TE constructs that solely rely on extrinsic vascularization from the periphery of the construct to appear compulsively ineffective 30. As oxygen and nutrition supply of the cells is limited to a maximum range of 200 μm into a given matrix, the nutritional supply by diffusion alone necessarily brings difficulties with itself. To overcome the oftentimes limited survival of cells in the centre of a large construct – because of the initially lacking vascularization – the in vivo creation of arterio-venous loops evolved over the last years. It aims to generate constructs with a predictable and dedicated neovascular network that allows for sufficient vascular supply directly after the vascular connection to the recipient bed has been created 31 (Fig. 3). This necessitates microsurgical skills and makes this approach highly dependent on expert microsurgeons. This concept is clinically used in microsurgical centres to customize tissues that are thought to be transplanted into a special problem wound or defect zone as so called pre-fabricated or pre-laminated free flaps [32–44] that rely on the intrinsic mode of vascularization and are not depending on extrinsic vascularization. Although this type of flap is usually not the first line of defect coverage, the requirements for more complex clinical tissue replacement with various surfaces or customized soft- and hard-tissue flaps is increasing. However, this modification clinically depends on at least two different interventions when 3D complex tissue substitutes are to be implanted following their pre-vascularization [45,46]. The critical influence of the local recipient environment is minimized with this technique.


Tissue engineering and regenerative medicine -where do we stand?

Horch RE, Kneser U, Polykandriotis E, Schmidt VJ, Sun J, Arkudas A - J. Cell. Mol. Med. (2012)

Corrosion Cast of an axial neovascular assembly, in vivo vascular construct, 2 weeks after vascular induction. Left: Overview of a nascent capillary network. Middle: sprouting angiogenic event. A new capillary sprout emerging from the parent vessel by endothelial pericytic proliferation Right: intussusceptive angiogenic events. The parent vessel is divided into two distinct new vessels for the purpose of vascular growth or remodelling.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3823070&req=5

fig03: Corrosion Cast of an axial neovascular assembly, in vivo vascular construct, 2 weeks after vascular induction. Left: Overview of a nascent capillary network. Middle: sprouting angiogenic event. A new capillary sprout emerging from the parent vessel by endothelial pericytic proliferation Right: intussusceptive angiogenic events. The parent vessel is divided into two distinct new vessels for the purpose of vascular growth or remodelling.
Mentions: The clinical scenario encompasses a number of difficult problems to solve as radiation therapy has become one of the main treatment options within the concept of multimodal tumour therapy. Following irradiation, the recipient site for any kind of tissue transfer lacks a normal vascularization potential. Neovascularization cannot easily appear from irradiated wound beds, and makes the common approach of transplanting TE constructs that solely rely on extrinsic vascularization from the periphery of the construct to appear compulsively ineffective 30. As oxygen and nutrition supply of the cells is limited to a maximum range of 200 μm into a given matrix, the nutritional supply by diffusion alone necessarily brings difficulties with itself. To overcome the oftentimes limited survival of cells in the centre of a large construct – because of the initially lacking vascularization – the in vivo creation of arterio-venous loops evolved over the last years. It aims to generate constructs with a predictable and dedicated neovascular network that allows for sufficient vascular supply directly after the vascular connection to the recipient bed has been created 31 (Fig. 3). This necessitates microsurgical skills and makes this approach highly dependent on expert microsurgeons. This concept is clinically used in microsurgical centres to customize tissues that are thought to be transplanted into a special problem wound or defect zone as so called pre-fabricated or pre-laminated free flaps [32–44] that rely on the intrinsic mode of vascularization and are not depending on extrinsic vascularization. Although this type of flap is usually not the first line of defect coverage, the requirements for more complex clinical tissue replacement with various surfaces or customized soft- and hard-tissue flaps is increasing. However, this modification clinically depends on at least two different interventions when 3D complex tissue substitutes are to be implanted following their pre-vascularization [45,46]. The critical influence of the local recipient environment is minimized with this technique.

Bottom Line: As a typical example in translational medicine, the discovery of a new type of cells called Telocytes that have been described in many organs and have been detected by electron microscopy opens another gate to RM.This article is intended to give an overview over some of the most recent developments and possible applications in RM through the perspective of TE achievements and cellular research.The synthesis of TE with innovative methods of molecular biology and stem-cell technology appears to be very promising.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic and Hand Surgery And Laboratory for Tissue Engineering and Regenerative Medicine, Friedrich Alexander University Erlangen-Nuernberg, Erlangen, Germany. raymund.horch@uk-erlangen.de

Show MeSH
Related in: MedlinePlus