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Autonomously vascularized cellular constructs in tissue engineering: opening a new perspective for biomedical science.

Polykandriotis E, Arkudas A, Horch RE, Stürzl M, Kneser U - J. Cell. Mol. Med. (2007 Jan-Feb)

Bottom Line: The cell itself is situated at the cross-roads leading to different orders of scale, from molecule to organism and different levels of function, from biochemistry to macrophysiology.Extensive in vitro investigations have dissected a vast amount of cellular phenomena and the role of a number of bioactive substances has been elucidated in the past.Further, recombinant DNA technologies allow modulation of the expression profiles of virtually all kinds of cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic and Hand Surgery, University of Erlangen Medical Center, Erlangen, Germany.

ABSTRACT
In tissue engineering cell cultures play a crucial role besides the matrix materials for the end of substituting lost tissue functions. The cell itself is situated at the cross-roads leading to different orders of scale, from molecule to organism and different levels of function, from biochemistry to macrophysiology. Extensive in vitro investigations have dissected a vast amount of cellular phenomena and the role of a number of bioactive substances has been elucidated in the past. Further, recombinant DNA technologies allow modulation of the expression profiles of virtually all kinds of cells. However, issues of vascularization in vivo limit transferability of these observations and restrict upscaling into clinical applications. Novel in vivo models of vascularization have evolved inspired from reconstructive microsurgical concepts and they encompass axial neovascularization by means of vascular induction. This work represents a brief description of latest developments and potential applications of neovascularization and angiogenesis in tissue engineering.

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Related in: MedlinePlus

Sprouting (*) and branching (+) in the neocapillary network. Incomplete filling of the capillaries (#) is characterized by a rounded tip. Sprouts are marked by spiked tips. (Scanning electron microscopy of corrosion casts.)
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fig07: Sprouting (*) and branching (+) in the neocapillary network. Incomplete filling of the capillaries (#) is characterized by a rounded tip. Sprouts are marked by spiked tips. (Scanning electron microscopy of corrosion casts.)

Mentions: Scanning electron microscopy of microvascular corrosion casts is a powerful method that allowed us to study the spatial arrangement of the capillaries with a high resolution (Fig. 6). The three dimensional distribution of angiogenetic sprouts and neocapillary branching can be readily visualized (Fig. 7).The site of a sprout displays an increased permeability.Therefore, upon injection of the resin, the heparinized saline can escape at the tip of the sprout and the resin replacing it assumes a very distinct spike-like shape.Partially filled branches can be easily distinguished due to a blunt rounded tip. (Fig. 7). Hot spots of increased angiogenesis can be localized by an increased occurance of such spikes or alternatively by ring-like structures indicating non-sprouting angiogenesis (Fig. 8). The authors were able to demonstrate direct luminal sprouting from the venous and graft segments of the AV loop. The impression of the vascular wall on the cast provides further information about the morphology of angiogenesis.Vascular segments subjected to arterial flow conditions, show a highly oriented pattern of endothelial lining with spindle like cells parallel to the flow direction. In speciments taken from implants that remained in the organism for 4 weeks or longer, signs of vascular maturation can be demonstrated. The processes of regression and persistence lead to a highly organized network of vessels of different calibre arranged in an ordered hierarchy from artery, to arteriole, to capillaries and post-capillary venules that evacuate into veins [28]. Latest advances in micro CT allow visualization of vessels with a resolution as low as 10 μm. Quantitative evaluation of three-dimensional vascular networks will soon be feasible in small animals [29].


Autonomously vascularized cellular constructs in tissue engineering: opening a new perspective for biomedical science.

Polykandriotis E, Arkudas A, Horch RE, Stürzl M, Kneser U - J. Cell. Mol. Med. (2007 Jan-Feb)

Sprouting (*) and branching (+) in the neocapillary network. Incomplete filling of the capillaries (#) is characterized by a rounded tip. Sprouts are marked by spiked tips. (Scanning electron microscopy of corrosion casts.)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4401217&req=5

fig07: Sprouting (*) and branching (+) in the neocapillary network. Incomplete filling of the capillaries (#) is characterized by a rounded tip. Sprouts are marked by spiked tips. (Scanning electron microscopy of corrosion casts.)
Mentions: Scanning electron microscopy of microvascular corrosion casts is a powerful method that allowed us to study the spatial arrangement of the capillaries with a high resolution (Fig. 6). The three dimensional distribution of angiogenetic sprouts and neocapillary branching can be readily visualized (Fig. 7).The site of a sprout displays an increased permeability.Therefore, upon injection of the resin, the heparinized saline can escape at the tip of the sprout and the resin replacing it assumes a very distinct spike-like shape.Partially filled branches can be easily distinguished due to a blunt rounded tip. (Fig. 7). Hot spots of increased angiogenesis can be localized by an increased occurance of such spikes or alternatively by ring-like structures indicating non-sprouting angiogenesis (Fig. 8). The authors were able to demonstrate direct luminal sprouting from the venous and graft segments of the AV loop. The impression of the vascular wall on the cast provides further information about the morphology of angiogenesis.Vascular segments subjected to arterial flow conditions, show a highly oriented pattern of endothelial lining with spindle like cells parallel to the flow direction. In speciments taken from implants that remained in the organism for 4 weeks or longer, signs of vascular maturation can be demonstrated. The processes of regression and persistence lead to a highly organized network of vessels of different calibre arranged in an ordered hierarchy from artery, to arteriole, to capillaries and post-capillary venules that evacuate into veins [28]. Latest advances in micro CT allow visualization of vessels with a resolution as low as 10 μm. Quantitative evaluation of three-dimensional vascular networks will soon be feasible in small animals [29].

Bottom Line: The cell itself is situated at the cross-roads leading to different orders of scale, from molecule to organism and different levels of function, from biochemistry to macrophysiology.Extensive in vitro investigations have dissected a vast amount of cellular phenomena and the role of a number of bioactive substances has been elucidated in the past.Further, recombinant DNA technologies allow modulation of the expression profiles of virtually all kinds of cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic and Hand Surgery, University of Erlangen Medical Center, Erlangen, Germany.

ABSTRACT
In tissue engineering cell cultures play a crucial role besides the matrix materials for the end of substituting lost tissue functions. The cell itself is situated at the cross-roads leading to different orders of scale, from molecule to organism and different levels of function, from biochemistry to macrophysiology. Extensive in vitro investigations have dissected a vast amount of cellular phenomena and the role of a number of bioactive substances has been elucidated in the past. Further, recombinant DNA technologies allow modulation of the expression profiles of virtually all kinds of cells. However, issues of vascularization in vivo limit transferability of these observations and restrict upscaling into clinical applications. Novel in vivo models of vascularization have evolved inspired from reconstructive microsurgical concepts and they encompass axial neovascularization by means of vascular induction. This work represents a brief description of latest developments and potential applications of neovascularization and angiogenesis in tissue engineering.

Show MeSH
Related in: MedlinePlus