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Regression and persistence: remodelling in a tissue engineered axial vascular assembly.

Polykandriotis E, Euler S, Arkudas A, Pryymachuk G, Beier JP, Greil P, Dragu A, Lametschwandtner A, Kneser U, Horch RE - J. Cell. Mol. Med. (2009)

Bottom Line: After the fourth week the absolute number of vessels within the ROI decreased (P < 0.03) whereas, on the contrary, the fractional area of all segments increased (P < 0.02).The variance in calibre was significantly increased in the 8-week group (P < 0.05).Phenomena of remodelling were evaluated quantitatively in a neovascular network and variance could be proposed as a parameter of net vascular maturation.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic and Hand Surgery, University of Erlangen, Erlangen, Germany. elias.polykandriotis@uk-erlangen.de

ABSTRACT
In later stages of vasculoangiogenesis a vascular network is going through a metamorphosis for optimal perfusion and economy of energy. In this study we make a quantitative approach to phenomena of remodelling in a bioartificial neovascular network and suggest variance of calibre as a parameter of neovascular maturation. For this study, 18 male Lewis rats were subjected to the AV loop operation in combination with a hard porous biogenic matrix and an isolation chamber. The animals were allocated into three groups for different explantation intervals set to 2, 4 and 8 weeks, respectively. Collective attributes like vascular density, percent fractional area and variance of calibre were evaluated for a predefined region of interest (ROI). Late morphogenesis was evaluated by means of scanning electron microscopy. After the fourth week the absolute number of vessels within the ROI decreased (P < 0.03) whereas, on the contrary, the fractional area of all segments increased (P < 0.02). The variance in calibre was significantly increased in the 8-week group (P < 0.05). Lymphatic growth after week 4, early pericyte migration as well as intussusceptive angiogenesis were identified immunohistologically. Phenomena of remodelling were evaluated quantitatively in a neovascular network and variance could be proposed as a parameter of net vascular maturation.

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(A) For construction of the AV loop, a segment of the right femoral vein is being harvested and interposed between the left femoral artery and vein. (B) The AV loop is placed in the peripheral groove of the porous matrix. Neovascular sprouts enter the matrix and render it vascularized. The construct is placed into an isolation chamber with an aperture for entrance of the vascular pedicle of the AV loop. (C) Method of analysis: A ROI was defined in a 500 μm radius (r) around the vascular axis (A), excluding the loop vessel itself. The image was rendered bimodal with a standardized threshold set to black stained India ink-filled vessels. The bimodal images were detected and analyzed for % FA of vessels against ROI (% FA), absolute capillary number (CapNo) in ROI as well as differential vascular calibre in ROI. In this way a developing vascular segment rather than an expanding one was evaluated. (D) Example on an acquired image.
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fig01: (A) For construction of the AV loop, a segment of the right femoral vein is being harvested and interposed between the left femoral artery and vein. (B) The AV loop is placed in the peripheral groove of the porous matrix. Neovascular sprouts enter the matrix and render it vascularized. The construct is placed into an isolation chamber with an aperture for entrance of the vascular pedicle of the AV loop. (C) Method of analysis: A ROI was defined in a 500 μm radius (r) around the vascular axis (A), excluding the loop vessel itself. The image was rendered bimodal with a standardized threshold set to black stained India ink-filled vessels. The bimodal images were detected and analyzed for % FA of vessels against ROI (% FA), absolute capillary number (CapNo) in ROI as well as differential vascular calibre in ROI. In this way a developing vascular segment rather than an expanding one was evaluated. (D) Example on an acquired image.

Mentions: The design of the isolation chamber and the matrix have been described previously [21] (Fig. 1). Briefly, a flat cylindrical Teflon chamber with an aperture for the entering arteriovascular pedicle and a press-fitting cup was constructed by the Institute of Materials Science; Division of Glass and Ceramics, University of Erlangen. The porous matrix (Tutobone, Tutogen Medical, Neunkirchen, Germany) consisted of processed bovine cancellous bone in the form of a disc 9 mm in diameter and 5 mm in height. Around the periphery of the disc there was a 1.5 × 2 mm groove accommodating the arteriovenous loop.


Regression and persistence: remodelling in a tissue engineered axial vascular assembly.

Polykandriotis E, Euler S, Arkudas A, Pryymachuk G, Beier JP, Greil P, Dragu A, Lametschwandtner A, Kneser U, Horch RE - J. Cell. Mol. Med. (2009)

(A) For construction of the AV loop, a segment of the right femoral vein is being harvested and interposed between the left femoral artery and vein. (B) The AV loop is placed in the peripheral groove of the porous matrix. Neovascular sprouts enter the matrix and render it vascularized. The construct is placed into an isolation chamber with an aperture for entrance of the vascular pedicle of the AV loop. (C) Method of analysis: A ROI was defined in a 500 μm radius (r) around the vascular axis (A), excluding the loop vessel itself. The image was rendered bimodal with a standardized threshold set to black stained India ink-filled vessels. The bimodal images were detected and analyzed for % FA of vessels against ROI (% FA), absolute capillary number (CapNo) in ROI as well as differential vascular calibre in ROI. In this way a developing vascular segment rather than an expanding one was evaluated. (D) Example on an acquired image.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4496123&req=5

fig01: (A) For construction of the AV loop, a segment of the right femoral vein is being harvested and interposed between the left femoral artery and vein. (B) The AV loop is placed in the peripheral groove of the porous matrix. Neovascular sprouts enter the matrix and render it vascularized. The construct is placed into an isolation chamber with an aperture for entrance of the vascular pedicle of the AV loop. (C) Method of analysis: A ROI was defined in a 500 μm radius (r) around the vascular axis (A), excluding the loop vessel itself. The image was rendered bimodal with a standardized threshold set to black stained India ink-filled vessels. The bimodal images were detected and analyzed for % FA of vessels against ROI (% FA), absolute capillary number (CapNo) in ROI as well as differential vascular calibre in ROI. In this way a developing vascular segment rather than an expanding one was evaluated. (D) Example on an acquired image.
Mentions: The design of the isolation chamber and the matrix have been described previously [21] (Fig. 1). Briefly, a flat cylindrical Teflon chamber with an aperture for the entering arteriovascular pedicle and a press-fitting cup was constructed by the Institute of Materials Science; Division of Glass and Ceramics, University of Erlangen. The porous matrix (Tutobone, Tutogen Medical, Neunkirchen, Germany) consisted of processed bovine cancellous bone in the form of a disc 9 mm in diameter and 5 mm in height. Around the periphery of the disc there was a 1.5 × 2 mm groove accommodating the arteriovenous loop.

Bottom Line: After the fourth week the absolute number of vessels within the ROI decreased (P < 0.03) whereas, on the contrary, the fractional area of all segments increased (P < 0.02).The variance in calibre was significantly increased in the 8-week group (P < 0.05).Phenomena of remodelling were evaluated quantitatively in a neovascular network and variance could be proposed as a parameter of net vascular maturation.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic and Hand Surgery, University of Erlangen, Erlangen, Germany. elias.polykandriotis@uk-erlangen.de

ABSTRACT
In later stages of vasculoangiogenesis a vascular network is going through a metamorphosis for optimal perfusion and economy of energy. In this study we make a quantitative approach to phenomena of remodelling in a bioartificial neovascular network and suggest variance of calibre as a parameter of neovascular maturation. For this study, 18 male Lewis rats were subjected to the AV loop operation in combination with a hard porous biogenic matrix and an isolation chamber. The animals were allocated into three groups for different explantation intervals set to 2, 4 and 8 weeks, respectively. Collective attributes like vascular density, percent fractional area and variance of calibre were evaluated for a predefined region of interest (ROI). Late morphogenesis was evaluated by means of scanning electron microscopy. After the fourth week the absolute number of vessels within the ROI decreased (P < 0.03) whereas, on the contrary, the fractional area of all segments increased (P < 0.02). The variance in calibre was significantly increased in the 8-week group (P < 0.05). Lymphatic growth after week 4, early pericyte migration as well as intussusceptive angiogenesis were identified immunohistologically. Phenomena of remodelling were evaluated quantitatively in a neovascular network and variance could be proposed as a parameter of net vascular maturation.

Show MeSH
Related in: MedlinePlus