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Tracking dynamic microvascular changes during healing after complete biopsy punch on the mouse pinna using optical microangiography.

Jung Y, Dziennis S, Zhi Z, Reif R, Zheng Y, Wang RK - PLoS ONE (2013)

Bottom Line: The highest rate of wound closure occurred between days 8 and 22.The vessel tortuosity increased during this time suggesting angiogenesis.The use of OMAG has great potential to improve our understanding of vascular and tissue responses to injury in order to develop more effective therapeutics.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Washington, Seattle, Washington, United States of America.

ABSTRACT
Optical microangiography (OMAG) and Doppler optical microangiography (DOMAG) are two non-invasive techniques capable of determining the tissue microstructural content, microvasculature angiography, and blood flow velocity and direction. These techniques were used to visualize the acute and chronic microvascular and tissue responses upon an injury in vivo. A tissue wound was induced using a 0.5 mm biopsy punch on a mouse pinna. The changes in the microangiography, blood flow velocity and direction were quantified for the acute (<30 min) wound response and the changes in the tissue structure and microangiography were determined for the chronic wound response (30 min-60 days). The initial wound triggered recruitment of peripheral capillaries, as well as redirection of main arterial and venous blood flow within 3 min. The complex vascular networks and new vessel formation were quantified during the chronic response using fractal dimension. The highest rate of wound closure occurred between days 8 and 22. The vessel tortuosity increased during this time suggesting angiogenesis. Taken together, these data signify that OMAG has the capability to track acute and chronic changes in blood flow, microangiography and structure during wound healing. The use of OMAG has great potential to improve our understanding of vascular and tissue responses to injury in order to develop more effective therapeutics.

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Determination of blood flow direction using DOMAG after induction of the wound on the mouse pinna.Projection view of the OMAG vascular map (A) before and (E) approximately 3 min after the wound. Flow direction within an artery and vein (B) before and (F) after the wound. The direction of arterial and venous flow is indicated by the red and blue dashed lines and arrows. (C) 3D color map of the axial flow velocity obtained with DOMAG before the wound. Blue indicates −1 mm/s and red indicates +1 mm/s. (G) 3D color map of the axial flow velocity obtained with DOMAG after the wound Blue indicates −0.4 mm/s and red indicates +0.4 mm/s. (D) 2D cross-sectional grey phase Doppler image of the axial flow velocity at the lines in (C). The grey scale velocity range is black −1 mm/s to white +1 mm/s. (H) 2D cross-sectional grey phase Doppler image of the axial flow velocity at the lines in (G). The grey scale velocity range is black −0.4 mm/s to white +0.4 mm/s. After the artery and vein branch, the vessels from the left branch (white box) show a reverse in flow direction, as opposed to the vessels from the right branch (yellow boxes) (I) Image of the whole ear indicating the flow direction after the wound. Red dashed line indicates arterial flow and blue dashed line indicates venous flow.
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pone-0057976-g002: Determination of blood flow direction using DOMAG after induction of the wound on the mouse pinna.Projection view of the OMAG vascular map (A) before and (E) approximately 3 min after the wound. Flow direction within an artery and vein (B) before and (F) after the wound. The direction of arterial and venous flow is indicated by the red and blue dashed lines and arrows. (C) 3D color map of the axial flow velocity obtained with DOMAG before the wound. Blue indicates −1 mm/s and red indicates +1 mm/s. (G) 3D color map of the axial flow velocity obtained with DOMAG after the wound Blue indicates −0.4 mm/s and red indicates +0.4 mm/s. (D) 2D cross-sectional grey phase Doppler image of the axial flow velocity at the lines in (C). The grey scale velocity range is black −1 mm/s to white +1 mm/s. (H) 2D cross-sectional grey phase Doppler image of the axial flow velocity at the lines in (G). The grey scale velocity range is black −0.4 mm/s to white +0.4 mm/s. After the artery and vein branch, the vessels from the left branch (white box) show a reverse in flow direction, as opposed to the vessels from the right branch (yellow boxes) (I) Image of the whole ear indicating the flow direction after the wound. Red dashed line indicates arterial flow and blue dashed line indicates venous flow.

Mentions: To determine the changes in blood flow velocity and direction, we imaged a small area of the mouse pinna. Figure 2A and 2E show the OMAG microangiography of the mouse pinna before and after (3 minutes) the wound. With DOMAG we calculated the blood flow velocity and direction. The three-dimensional color map for the direction of flow in four main vessels is shown in Figures 2C and 2G, where red and blue indicate flow against (arterial) and towards (venous) the incident OCT beam, respectively. The cross-section at the location of the white and yellow lines in Figures 2C and 2G are presented in Figures 2D and 2H, respectively, which presents the Doppler phase change image in the axial direction. The vessel directionality is indicated with the red (+) and blue (−) arrows, and represent downward and upward flow direction, respectively. The wound severed both arterial and venous vessels, and rapidly induced a reversal in blood flow direction in a branch of the downstream circulation (white box in Figure 2D and 2H). The other branch (yellow box in Figure 2D and 2H) maintained an intact flow direction. It is known that the arteries have smaller vessel diameters than the veins, and that the blood flow direction of the arteries is toward, while the vein is away from the edges of the pinna. The dashed arrows in Figures 2B and 2F indicate the flow direction from the designated arteries (red) and veins (blue). The main artery branches into two smaller vessels. Likewise, two smaller vessels converge into one larger vein. The comprehensive image (Figure 2I) presents a larger view of the blood flow after the wound, which caused a redirection of the flow. This figure helps to understand how the blood flow of the whole ear responds to supply the wound area after the injury. By using the three-dimensional information of the vessels presented in Figures 2B and 2F, we estimated the Doppler angle which allowed us to calculate the total blood flow inside the vessels of interest. As an example of DOMAG's ability to quantify blood flow, we determined the absolute flow velocity of the artery (white box in Figure 2D) to be reduced after the wound from ∼6 mm/s to 1.5 mm/s.


Tracking dynamic microvascular changes during healing after complete biopsy punch on the mouse pinna using optical microangiography.

Jung Y, Dziennis S, Zhi Z, Reif R, Zheng Y, Wang RK - PLoS ONE (2013)

Determination of blood flow direction using DOMAG after induction of the wound on the mouse pinna.Projection view of the OMAG vascular map (A) before and (E) approximately 3 min after the wound. Flow direction within an artery and vein (B) before and (F) after the wound. The direction of arterial and venous flow is indicated by the red and blue dashed lines and arrows. (C) 3D color map of the axial flow velocity obtained with DOMAG before the wound. Blue indicates −1 mm/s and red indicates +1 mm/s. (G) 3D color map of the axial flow velocity obtained with DOMAG after the wound Blue indicates −0.4 mm/s and red indicates +0.4 mm/s. (D) 2D cross-sectional grey phase Doppler image of the axial flow velocity at the lines in (C). The grey scale velocity range is black −1 mm/s to white +1 mm/s. (H) 2D cross-sectional grey phase Doppler image of the axial flow velocity at the lines in (G). The grey scale velocity range is black −0.4 mm/s to white +0.4 mm/s. After the artery and vein branch, the vessels from the left branch (white box) show a reverse in flow direction, as opposed to the vessels from the right branch (yellow boxes) (I) Image of the whole ear indicating the flow direction after the wound. Red dashed line indicates arterial flow and blue dashed line indicates venous flow.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585416&req=5

pone-0057976-g002: Determination of blood flow direction using DOMAG after induction of the wound on the mouse pinna.Projection view of the OMAG vascular map (A) before and (E) approximately 3 min after the wound. Flow direction within an artery and vein (B) before and (F) after the wound. The direction of arterial and venous flow is indicated by the red and blue dashed lines and arrows. (C) 3D color map of the axial flow velocity obtained with DOMAG before the wound. Blue indicates −1 mm/s and red indicates +1 mm/s. (G) 3D color map of the axial flow velocity obtained with DOMAG after the wound Blue indicates −0.4 mm/s and red indicates +0.4 mm/s. (D) 2D cross-sectional grey phase Doppler image of the axial flow velocity at the lines in (C). The grey scale velocity range is black −1 mm/s to white +1 mm/s. (H) 2D cross-sectional grey phase Doppler image of the axial flow velocity at the lines in (G). The grey scale velocity range is black −0.4 mm/s to white +0.4 mm/s. After the artery and vein branch, the vessels from the left branch (white box) show a reverse in flow direction, as opposed to the vessels from the right branch (yellow boxes) (I) Image of the whole ear indicating the flow direction after the wound. Red dashed line indicates arterial flow and blue dashed line indicates venous flow.
Mentions: To determine the changes in blood flow velocity and direction, we imaged a small area of the mouse pinna. Figure 2A and 2E show the OMAG microangiography of the mouse pinna before and after (3 minutes) the wound. With DOMAG we calculated the blood flow velocity and direction. The three-dimensional color map for the direction of flow in four main vessels is shown in Figures 2C and 2G, where red and blue indicate flow against (arterial) and towards (venous) the incident OCT beam, respectively. The cross-section at the location of the white and yellow lines in Figures 2C and 2G are presented in Figures 2D and 2H, respectively, which presents the Doppler phase change image in the axial direction. The vessel directionality is indicated with the red (+) and blue (−) arrows, and represent downward and upward flow direction, respectively. The wound severed both arterial and venous vessels, and rapidly induced a reversal in blood flow direction in a branch of the downstream circulation (white box in Figure 2D and 2H). The other branch (yellow box in Figure 2D and 2H) maintained an intact flow direction. It is known that the arteries have smaller vessel diameters than the veins, and that the blood flow direction of the arteries is toward, while the vein is away from the edges of the pinna. The dashed arrows in Figures 2B and 2F indicate the flow direction from the designated arteries (red) and veins (blue). The main artery branches into two smaller vessels. Likewise, two smaller vessels converge into one larger vein. The comprehensive image (Figure 2I) presents a larger view of the blood flow after the wound, which caused a redirection of the flow. This figure helps to understand how the blood flow of the whole ear responds to supply the wound area after the injury. By using the three-dimensional information of the vessels presented in Figures 2B and 2F, we estimated the Doppler angle which allowed us to calculate the total blood flow inside the vessels of interest. As an example of DOMAG's ability to quantify blood flow, we determined the absolute flow velocity of the artery (white box in Figure 2D) to be reduced after the wound from ∼6 mm/s to 1.5 mm/s.

Bottom Line: The highest rate of wound closure occurred between days 8 and 22.The vessel tortuosity increased during this time suggesting angiogenesis.The use of OMAG has great potential to improve our understanding of vascular and tissue responses to injury in order to develop more effective therapeutics.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Washington, Seattle, Washington, United States of America.

ABSTRACT
Optical microangiography (OMAG) and Doppler optical microangiography (DOMAG) are two non-invasive techniques capable of determining the tissue microstructural content, microvasculature angiography, and blood flow velocity and direction. These techniques were used to visualize the acute and chronic microvascular and tissue responses upon an injury in vivo. A tissue wound was induced using a 0.5 mm biopsy punch on a mouse pinna. The changes in the microangiography, blood flow velocity and direction were quantified for the acute (<30 min) wound response and the changes in the tissue structure and microangiography were determined for the chronic wound response (30 min-60 days). The initial wound triggered recruitment of peripheral capillaries, as well as redirection of main arterial and venous blood flow within 3 min. The complex vascular networks and new vessel formation were quantified during the chronic response using fractal dimension. The highest rate of wound closure occurred between days 8 and 22. The vessel tortuosity increased during this time suggesting angiogenesis. Taken together, these data signify that OMAG has the capability to track acute and chronic changes in blood flow, microangiography and structure during wound healing. The use of OMAG has great potential to improve our understanding of vascular and tissue responses to injury in order to develop more effective therapeutics.

Show MeSH
Related in: MedlinePlus