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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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Left: Cross sectional area of vascular lumina in per cent (% FA) of total area of ROI detected in a radius 500 μm around the vascular axis. Development in all separate segments of the AV loop (vein, graft, artery) over the time intervals 2, 4 and 8 weeks. There is a steady increase over time in all segments indicative of a rise of the summation of the calibre and perfusion volume of all detected vessels. The highest per cent values are met with the vein, demonstrating the highest vasculoangiogenic activity in this region. After 8 weeks values for % FA are comparable all three segments, indicating achievement of a steady state. Right: Number of detected vascular lumina within the ROI. Past the 4th week, the number of lumina decreases in the non-arterial segments of the AV loop. Involution of a nascent vascular network in terms of regression of superfluous vessels happens in favour of necessary vascular conduits that persist to form feeding arterioles and draining venules, As angiogenesis in the vicinity of the artery is not as vivid as in the non arterial counterparts, phenomena of remodelling also take place later. For each bar n= 5 with 10 independent measurements, (*): P < 0.05. Error indicators show standard error of means.
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fig04: Left: Cross sectional area of vascular lumina in per cent (% FA) of total area of ROI detected in a radius 500 μm around the vascular axis. Development in all separate segments of the AV loop (vein, graft, artery) over the time intervals 2, 4 and 8 weeks. There is a steady increase over time in all segments indicative of a rise of the summation of the calibre and perfusion volume of all detected vessels. The highest per cent values are met with the vein, demonstrating the highest vasculoangiogenic activity in this region. After 8 weeks values for % FA are comparable all three segments, indicating achievement of a steady state. Right: Number of detected vascular lumina within the ROI. Past the 4th week, the number of lumina decreases in the non-arterial segments of the AV loop. Involution of a nascent vascular network in terms of regression of superfluous vessels happens in favour of necessary vascular conduits that persist to form feeding arterioles and draining venules, As angiogenesis in the vicinity of the artery is not as vivid as in the non arterial counterparts, phenomena of remodelling also take place later. For each bar n= 5 with 10 independent measurements, (*): P < 0.05. Error indicators show standard error of means.

Mentions: The variance of calibre of vascular lumina detected in the ROI at all segments was as follows: 2 weeks: 215.143 × 103 (SE 88.317 × 103), 4 weeks: 105.619 × 103 (SEM 31.108 × 103), 8 weeks: 643.455 × 103 (SEM 186.243 × 103). The variance in calibre increased significantly between weeks 2 and 8 (P < 0.05) as well as between weeks 4 and 8 (P < 0.01). Change of variance between weeks 2 and 4 was not significant (P= 0.18). The results are summarized in Figs 4 and 5.


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)

Left: Cross sectional area of vascular lumina in per cent (% FA) of total area of ROI detected in a radius 500 μm around the vascular axis. Development in all separate segments of the AV loop (vein, graft, artery) over the time intervals 2, 4 and 8 weeks. There is a steady increase over time in all segments indicative of a rise of the summation of the calibre and perfusion volume of all detected vessels. The highest per cent values are met with the vein, demonstrating the highest vasculoangiogenic activity in this region. After 8 weeks values for % FA are comparable all three segments, indicating achievement of a steady state. Right: Number of detected vascular lumina within the ROI. Past the 4th week, the number of lumina decreases in the non-arterial segments of the AV loop. Involution of a nascent vascular network in terms of regression of superfluous vessels happens in favour of necessary vascular conduits that persist to form feeding arterioles and draining venules, As angiogenesis in the vicinity of the artery is not as vivid as in the non arterial counterparts, phenomena of remodelling also take place later. For each bar n= 5 with 10 independent measurements, (*): P < 0.05. Error indicators show standard error of means.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4496123&req=5

fig04: Left: Cross sectional area of vascular lumina in per cent (% FA) of total area of ROI detected in a radius 500 μm around the vascular axis. Development in all separate segments of the AV loop (vein, graft, artery) over the time intervals 2, 4 and 8 weeks. There is a steady increase over time in all segments indicative of a rise of the summation of the calibre and perfusion volume of all detected vessels. The highest per cent values are met with the vein, demonstrating the highest vasculoangiogenic activity in this region. After 8 weeks values for % FA are comparable all three segments, indicating achievement of a steady state. Right: Number of detected vascular lumina within the ROI. Past the 4th week, the number of lumina decreases in the non-arterial segments of the AV loop. Involution of a nascent vascular network in terms of regression of superfluous vessels happens in favour of necessary vascular conduits that persist to form feeding arterioles and draining venules, As angiogenesis in the vicinity of the artery is not as vivid as in the non arterial counterparts, phenomena of remodelling also take place later. For each bar n= 5 with 10 independent measurements, (*): P < 0.05. Error indicators show standard error of means.
Mentions: The variance of calibre of vascular lumina detected in the ROI at all segments was as follows: 2 weeks: 215.143 × 103 (SE 88.317 × 103), 4 weeks: 105.619 × 103 (SEM 31.108 × 103), 8 weeks: 643.455 × 103 (SEM 186.243 × 103). The variance in calibre increased significantly between weeks 2 and 8 (P < 0.05) as well as between weeks 4 and 8 (P < 0.01). Change of variance between weeks 2 and 4 was not significant (P= 0.18). The results are summarized in Figs 4 and 5.

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