The microcirculation in acute murine cutaneous incisional wounds shows a spatial and temporal variation in the functionality of vessels

Abstract

A mouse perfusion model using fluorescently labeled dextran has been developed to investigate the functionality of blood vessels during cutaneous wound healing. By immunostaining cryostat sections of perfused wounds with antibodies that identify vessels, we were able to assess their functionality. There was an increase in the proportion of CD31(+)-perfused vessels in all wound regions with time, although the vessels of the wound margins and superficial granulation tissue (GT) took the longest to become perfused. More than 50% of the latter vessels were not perfused at 10 days postwounding. This is consistent with the growth of functional vessels from the wound base proceeding to the more superficial GT. The CD34 marker was expressed by a subpopulation of CD31(+) vessels. However, in contrast to CD31(+) vessels, the functionality of CD34(+) vessels did not change significantly with time and 50-75% of CD34(+) vessels in the GT and wound margins were nonfunctional. This might be explained either by apoptosis of the CD34(+) vessels or the loss of the marker with time. This study has important implications for assays of wound-healing angiogenesis based on histology and immunohistochemical markers for vessels, because vessel functionality differs both spatially and temporally during wound healing.

Pigment epithelium-derived factor as a multifunctional regulator of wound healing

“…The data presented here have implications for antiangiogenic therapies in cancer (5), as the extensive highly permeable microvascular network in wounds during the proliferative phase (8) has been compared with that of solid tumors (20,51). Similar to PEDF's ability to improve microvascular integrity in wounds, PEDF may promote the maturation of the tumor blood vessel microenvironment, increasing the response to therapy via more efficient delivery of chemotherapeutic agents to cancer cells located deep inside tumors (26).…”

“…Both antibodies did not contain sodium azide preservative. Time points for administration of antibodies were days 8,12,16, and 20 postwounding; wound samples were harvested at days 16,20, and 24 postinjury. Five mice from each group were randomly selected for death and tissue harvest at days 16 and 20.…”

“…During wound repair, the vascular network sprouts and regresses in a reproducible temporal pattern (62). Following a burst of hypoxia-driven angiogenesis during the proliferative phase of healing, neovessels that are immature and leaky (8) are systemically targeted for removal in the remodeling phase (62), whereas blood vessels essential for tissue homeostasis are preserved and reinforced by the recruitment of mural cells, e.g., vascular smooth muscle cells and pericytes (32,40). While angiogenesis is ongoing, fibroblasts (FBs) mediate the synthesis and reconstruction of the extracellular matrix (ECM) in the wound bed, and the two processes have reciprocal regulation (27,31,44,52).…”

Anti-Angiogenic Drugs: Involvement in Cutaneous Side Effects and Wound-Healing Complication

“…8 One explanation is that many of the vascular structures formed during the granulation phase are not functional. 11 These vessels have been found to be immature and highly permeable. 12 Similar vessels have been observed in the vasculature around tumors.…”

Panta Rhei: Neovascularization, Angiogenesis and Nutritive Perfusion in Wound Healing

“…This vascular architecture and condition was repeatedly found in several other studies. Bluff et al [57] were able to show that most of the new vessels in a healing wound were histologically visible but not effectively supplied with blood. This vascular insufficiency is also well known from the growth of malignant tumors where, under the influence of pro-angiogenic substances, the vascular network proves to be twisted, leaky, and often very ineffective for sufficient blood circulation [58,59].…”