MicroCT angiography detects vascular formation and regression in skin wound healing

Abstract

Properly regulated angiogenesis and arteriogenesis are essential for effective wound healing. Tissue injury induces robust new vessel formation and subsequent vessel maturation, which involves vessel regression and remodeling. Although formation of functional vasculature is essential for healing, alterations in vascular structure over the time course of skin wound healing are not well understood. Here, using high-resolution ex vivo X-ray micro-computed tomography (microCT), we describe the vascular network during healing of skin excisional wounds with highly detailed three-dimensional (3D) reconstructed images and associated quantitative analysis. We found that relative vessel volume, surface area and branching number are significantly decreased in wounds from day 7 to day 14 and 21. Segmentation and skeletonization analysis of selected branches from high-resolution images as small as 2.5 μm voxel size show that branching orders are decreased in the wound vessels during healing. In histological analysis, we found that the contrast agent fills mainly arterioles, but not small capillaries nor large veins. In summary, high-resolution microCT revealed dynamic alterations of vessel structures during wound healing. This technique may be useful as a key tool in the study of the formation and regression of wound vessels.

Live imaging of wound angiogenesis reveals macrophage orchestrated vessel sprouting and regression

“…Wound blood vessels subsequently increase in number and branch pattern until they peak at 7 DPI, after which they resolve away from the wound area, becoming more organised and beginning to return to a distribution and alignment pattern resembling unwounded skin by 14 DPI (Fig 1B-D). This time course of events complements and expands on previous studies examining sprouting and regression of wound blood vessels using completely different technologies such as MicroCT angiography imaging (Urao et al, 2016). ▸ Figure 1.…”

Non‐invasive longitudinal monitoring of angiogenesis in a murine full‐thickness cutaneous wound healing model using high‐resolution three‐dimensional ultrasound imaging

“…A CD31 antibody has frequently been used to stain endothelial cells. 11,21,24,25 In this study, the results of paired measurements obtained from 2D ultrasound images with the Color Doppler mode and immunohistologically stained sections on day 14 after wounding showed that Pearson's correlation coefficients were r=0.927, 0.871, 0.717, and 0.913 for wounds 1, 2, 3, and 4, respectively, indicating a correlation. This result showed that a strong correlation for % vascularity was obtained between paired 2D ultrasound imaging with the Color Doppler mode and sections immunohistologically stained for the anti-CD31 antibody.…”

“…Other imaging modalities such as laser speckle perfusion imaging 22,23 and ex vivo micro CT imaging 11 have been used to visualize the vasculature of wounds or burns; however, there are some limitations. Laser speckle perfusion imaging is a non-invasive technique for Therefore, due to these limitations, high-resolution ultrasound imaging is considered a suitable modality for longitudinally monitoring the 3D structure of the vasculature in full-thickness cutaneous wounds over the course of healing.…”

“…[8][9][10] Using this technique, Urao et al showed that highresolution micro CT revealed dynamic alterations in vessel 3D structures during cutaneous wound healing, and demonstrated the potential of this technique as a key tool in the study of the formation and regression of wound vessels. 11 However, to perform ex vivo micro CT, samples need to be harvested from the bodies of animals who receive a systemic vascular perfusion with X-ray contrast media. [8][9][10][11] Therefore, one limitation of this technique is that it may not have the ability to longitudinally evaluate angiogenesis over the course of healing.…”

“…11 However, to perform ex vivo micro CT, samples need to be harvested from the bodies of animals who receive a systemic vascular perfusion with X-ray contrast media. [8][9][10][11] Therefore, one limitation of this technique is that it may not have the ability to longitudinally evaluate angiogenesis over the course of healing.…”