Microcirculation surrounding end-stage human chronic skin wounds is associated with endoglin/CD146/ALK-1 expression, endothelial cell proliferation and an absence of p16Ink4a

Jiarong Wang; Dylan Tinney; Michael Grynyshyn; J Geoffrey Pickering; Adam Power; Luc Dubois; Douglas W Hamilton

doi:10.1111/wrr.13081

Microcirculation surrounding end-stage human chronic skin wounds is associated with endoglin/CD146/ALK-1 expression, endothelial cell proliferation and an absence of p16^Ink4a

Wound Repair Regen. 2023 May-Jun;31(3):321-337. doi: 10.1111/wrr.13081. Epub 2023 Apr 13.

Authors

Jiarong Wang^{1

2}, Dylan Tinney¹, Michael Grynyshyn¹, J Geoffrey Pickering^{3

4}, Adam Power⁵, Luc Dubois⁵, Douglas W Hamilton¹

Affiliations

¹ Department of Anatomy & Cell Biology, University of Western Ontario, London, Ontario, Canada.
² Division of Vascular Surgery, West China Hospital, Sichuan University, Chengdu, China.
³ Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.
⁴ Division of Cardiology, University of Western Ontario, London, Ontario, Canada.
⁵ Division of Vascular Surgery, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.

PMID: 37017097
DOI: 10.1111/wrr.13081

Abstract

Angiogenesis is an essential part of normal skin healing, re-establishing blood flow in developing granulation tissue. Non-healing skin wounds are associated with impaired angiogenesis and although the role of re-establishing macroscopic blood flow to limbs to prevent wound chronicity is well investigated, less is known about vascular alterations at the microcirculatory level. We hypothesised that significant phenotypic changes would be evident in blood vessels surrounding chronic skin wounds. Wound edge tissue, proximal to wound (2 cm from wound edge) and non-involved skin (>10 cm from wound edge) was harvested under informed consent from 20 patients undergoing elective amputation due to critical limb ischemia. To assess blood vessel structure and viability, tissue was prepared for histological analysis and labelled with antibodies specific for PECAM-1 (CD31), CD146, endoglin, ALK-1, ALK-5, and p16^Ink4a as a marker of cellular senescence. Density of microvasculature was significantly increased in wound edge dermis, which was concomitant with increased labelling for endoglin and CD146. The number of CD31 positive vessel density was unchanged in wound edge tissue relative to non-involved tissue. Co-labelling of endoglin with the transforming growth factor receptor ALK-1, and to a lesser extent ALK-5, demonstrated activation of endothelial cells which correlated with PCNA labelling indicative of proliferation. Analysis of p16^Ink4a staining showed a complete lack of immunoreactivity in the vasculature and dermis, although staining was evident in sub-populations of keratinocytes. We conclude that the endoglin-ALK-1-endothelial proliferation axis is active in the vasculature at the edge of chronic skin wounds and is not associated with p16^Ink4a mediated senescence. This information could be further used to guide treatment of chronic skin wounds and optimise debridement protocols.

Keywords: endoglin; hypoxia; microcirculation; neovascularisation; senescence.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

CD146 Antigen
Cell Proliferation
Cyclin-Dependent Kinase Inhibitor p16*
Endoglin
Endothelial Cells
Humans
Microcirculation
Receptor Protein-Tyrosine Kinases
Skin / pathology
Wound Healing*

Substances

Endoglin
Cyclin-Dependent Kinase Inhibitor p16
CD146 Antigen
Receptor Protein-Tyrosine Kinases

Grants and funding

247506/CIHR/Canada