Endothelial glycocalyx dimensions are reduced in growing collateral arteries and modulate leucocyte adhesion in arteriogenesis

Abstract

During collateral artery growth, monocytes adhere to the endothelium and secrete cytokines from the perivascular space promoting arteriogenesis. Recently, the endothelial glycocalyx has been shown to modulate leucocyte infiltration in atherogenic regions. The role of this endothelial surface coating in arteriogenesis, however, has not been investigated so far. We now report that local plasma levels of hyaluronic acid are specifically increased in collateral arterial blood of coronary artery disease patients and hypothesized that components of the endothelial glycocalyx are shed during arteriogenesis, resulting in decreased glycocalyx dimensions and an increased leucocyte extravasation. In a rabbit model of femoral artery ligation, electron microscopy revealed a decrease in glycocalyx dimensions in collateral arteries compared with quiescent anastomoses (67.5 ± 47.2 nm versus 101.0 ± 11.3 nm; P < 0.001). This decrease was correlated with a higher number of perivascular macrophages around collateral arteries. The additional glycocalyx perturbation by local hyaluronidase infusion almost completely removed the endothelial surface layer and temporarily stimulated leucocyte accumulation in the perivascular space. However, complete perturbation of the glycocalyx by hyaluronidase infusion resulted in a significant attenuation of collateral artery growth assessed by microsphere-based perfusion measurements (ml/min/100 mmHg: hyaluronidase: 27.5 ± 3.5; Controls: 47.1 ± 3.83; P < 0.001) and a lower percentage of actively proliferating vascular smooth muscle cells. A decreased expression of the shear-stress regulated pro-arteriogenic genes eNOS and TGF-β1 suggests an impaired mechanotransduction as the underlying mechanisms. For the first time, we describe the role of the endothelial glycocalyx in collateral artery growth. Although complete abrogation led to attenuated arteriogenesis, shedding of glycocalyx components is observed during collateral artery growth.

Inhibition of Hyaluronan Synthesis Accelerates Murine Atherosclerosis

“…The assumption of steric hindrance of interactions between leukocyte and EC through the glycocalyx is supported by the fact that adhesion of leukocytes to the endothelium increases on the enzymatic removal of the glycocalyx. 34,35 This finding was complemented in the present study by increased macrophage retention in vascular lesions after short-term and long-term treatment with 4-MU. Furthermore, 2-week treatment with 4-MU also increased the number of macrophages that were recruited in an acute model of inflammation.…”

Plasma hyaluronan and collateral development in patients with coronary artery disease

“…Grundmann et al [20] recently reported that local plasma levels of hyaluronic acid are specifically increased in collateral arterial blood. In addition, tissues enriched in HA may undergo expansion because of the ability of the molecule to bind to large amounts of water, thus creating a loose, hydrated microenvironment that facilitates cell migration and proliferation, which are two critical events in angiogenesis and arteriogenesis [21].…”

FoxP1 Stimulates Angiogenesis by Repressing the Inhibitory Guidance Protein Semaphorin 5B in Endothelial Cells

“…Unilateral femoral artery occlusion was performed in C57/Bl6J mice (Charles River Lab., Sulzfeld, Germany) under anaesthesia with ketamin and xylazin by double ligation of the superficial femoral artery proximal to the deep femoral artery and the distal femoral artery just above the knee joint as previously described [17], [18]. Tissue of the gastrocnemius and soleus muscles was carefully dissected from the lower leg and snap-frozen in liquid nitrogen until further analysis.…”