Circulating Monocytes Expressing CD31

Abstract

To identify the roles of various circulating cells (eg, endothelial and/or stem and progenitor cells) in angiogenesis, we parabiosed a wild-type syngeneic mouse with a transgenic syngeneic green fluorescent protein mouse. Following the establishment of a common circulation between these parabionts, we investigated acute (7 to 10 days), subacute (2 to 3 weeks), and chronic (4 to 6 weeks) phases of angiogenesis in wildtype mice using wound healing, implanted gel foam fragments, and subcutaneous tumor assays, respectively. We found that under in vitro conditions, circulating murine monocytes expressed F4/80, CD31, and vascular endothelial growth factor receptor 2, but neither CD133 nor von Willebrand factor, whereas murine endothelial cells expressed CD31, vascular endothelial growth factor receptor 2, and von Willebrand factor, but neither CD133 nor F4/80. Immunofluorescence analysis revealed that green fluorescent proteinpositive cells in the walls of new vessels in wounds , gel foam blocks , and tumors expressed both F4/80 and CD31 , that is , macrophages. Pericytes , cells that express both CD31 and desmin , were found both in the walls of tumor-associated vessels and within tumors. Collectively , these data demonstrate that monocytes (ie , cells that express both CD31 and F4/80) may be recruited to the site of tissue injury and directly contribute to angiogenesis , reaffirming the close relationships between various cell types within the reticuloendothelial system and suggesting possible targets for anticancer treatments.

Hematogenous Metastasis of Ovarian Cancer: Rethinking Mode of Spread

“…We took care during the experiments to avoid twisting by using a flexible cohesive veterinarian bandage (1-in width, cat# COFLEX1, Med-Vet International, Mettawa, IL). Two weeks later, Evans blue dye was injected into the tail vein of one of the parabionts to confirm common circulation (Kim et al, 2009). Specifically, 2 weeks after anastomosis, the host mice were injected with tumor cells either into the peritoneal cavity or directly into the ovary.…”

Early effects of dexamethasone and anti-VEGF therapy in an inflammatory corneal neovascularization model

“…For example, stromal invasion of leukocytes (Bourghardt Peebo et al, 2007;Fagerholm and Gan, 2001;Gong and Koh, 2010;Nakao et al, 2012) which produce pro-angiogenic cytokines, precede and promote vessel invasion, and at a later stage could reactivate vessel growth upon cessation of treatment (Cursiefen et al, 2004;Gong and Koh, 2010;Lu et al, 2012;Sakurai et al, 2003;Sunderkötter et al, 1994;Tazzyman et al, 2013). Besides this paracrine function, evidence is mounting that inflammatory cells may have a more direct role in tissue remodeling and the formation of new vessels (Bourghardt Peebo et al, 2011;Fantin et al, 2010;Kim et al, 2009;Maruyama et al, 2005).…”

Bone marrow−derived cells do not engraft into skeletal muscle microvasculature but promote angiogenesis after acute injury

“…To date various cell populations including peripheral blood and bone marrow (BM) derived cells have been reported to promote angiogenesis and contributing to muscle vasculature [2–6]. However, many of the markers used to evaluate vascular contribution including Tie2 and CD31, are not exclusive to endothelial cells and can be expressed by circulating leukocytes, including monocytes [7–11]. Due to such overlap, putative vascular regeneration by BM derived populations is not easily distinguished from inflammatory cells responding to injury.…”