Hydrogen Sulphide Release via the Angiotensin Converting Enzyme Inhibitor Zofenopril Prevents Intimal Hyperplasia in Human Vein Segments and in a Mouse Model of Carotid Artery Stenosis

Abstract

WHAT THIS PAPER ADDSThe current strategies to reduce intimal hyperplasia (IH) rely principally on local drug delivery, in an endovascular approach. The oral angiotensin converting enzyme inhibitor (ACEi) zofenopril has additional effects to other non-sulfyhydrated ACEi to prevent intimal hyperplasia and re-stenosis. Given the number of patients treated with ACEi worldwide, these findings call for further prospective clinical trials to test the benefits of sulfhydrated ACEi over classic ACEi for the prevention of re-stenosis in hypertensive patients.Objective: Hypertension is a major risk factor for intimal hyperplasia (IH) and re-stenosis following vascular and endovascular interventions. Preclinical studies suggest that hydrogen sulphide (H 2 S), an endogenous gasotransmitter, limits re-stenosis. While there is no clinically available pure H 2 S releasing compound, the sulfhydryl containing angiotensin converting enzyme inhibitor zofenopril is a source of H 2 S. Here, it was hypothesised that zofenopril, due to H 2 S release, would be superior to other non-sulfhydryl containing angiotensin converting enzyme inhibitors (ACEi) in reducing intimal hyperplasia. Methods: Spontaneously hypertensive male Cx40 deleted mice (Cx40 e/e ) or wild type (WT) littermates were randomly treated with enalapril 20 mg or zofenopril 30 mg. Discarded human vein segments and primary human smooth muscle cells (SMCs) were treated with the active compound enalaprilat or zofenoprilat. IH was evaluated in mice 28 days after focal carotid artery stenosis surgery and in human vein segments cultured for seven days ex vivo. Human primary smooth muscle cell (SMC) proliferation and migration were studied in vitro.Results: Compared with control animals (intima/media thickness 2.3 AE 0.33 mm), enalapril reduced IH in Cx40 e/e hypertensive mice by 30% (1.7 AE 0.35 mm; p ¼ .037), while zofenopril abrogated IH (0.4 AE 0.16 mm; p < .002 vs. control and p > .99 vs. sham operated Cx40 e/e mice). In WT normotensive mice, enalapril had no effect (0.9665 AE 0.2 mm in control vs. 1.140 AE 0.27 mm; p > .99), while zofenopril also abrogated IH (0.1623 AE 0.07 mm; p < .008 vs. control and p > .99 vs. sham operated WT mice). Zofenoprilat, but not enalaprilat, also prevented IH in human vein segments ex vivo. The effect of zofenopril on carotid and SMCs correlated with reduced SMC proliferation and migration. Zofenoprilat inhibited the mitogen activated protein kinase and mammalian target of rapamycin pathways in SMCs and human vein segments. Conclusion: Zofenopril provides extra beneficial effects compared with non-sulfhydryl ACEi in reducing SMC proliferation and re-stenosis, even in normotensive animals. These findings may hold broad clinical implications for patients suffering from vascular occlusive diseases and hypertension.

Vascular smooth muscle cells in intimal hyperplasia, an update

“…On the contrary, CSE overexpression decreases IH formation in a murine model of vein graft by carotid-interposition cuff technique (Trocha et al, 2020). We and others demonstrated that several H 2 S donors inhibit IH in vivo in various models in rats (Meng et al, 2007), rabbits (Ma et al, 2012), mice (Yang et al, 2012;Macabrey et al, 2022a;Macabrey et al, 2022b), and in human great saphenous vein segments ex-vivo (Longchamp et al, 2019;Macabrey et al, 2022a;Macabrey et al, 2022b). H 2 S also directly inhibits VSMC proliferation and migration (Yang et al, 2006;Ma et al, 2012;Longchamp et al, 2019).…”

“…Frontiers in Physiology frontiersin.org pathway (Macabrey et al, 2022a). H 2 S also limit MMP2 expression and ECMs degradation, reducing VSMCs migration (Yang et al, 2010;Yang et al, 2012).…”

Sodium thiosulfate, a source of hydrogen sulfide, stimulates endothelial cell proliferation and neovascularization

“…All conditions were tested in parallel. Cells were fixed in ice-cold methanol 100 and immunostained for BrdU as previously described ( 23 , 26 , 30 ). Images were acquired using a Nikon Eclipse 90i microscope.…”

Clinical Use of Hydrogen Sulfide to Protect Against Intimal Hyperplasia

“…Furthermore, Zofenopril prevents IH in an ex vivo model of IH in human saphenous vein. The effect of Zofenopril on IH correlates with reduced VSMC proliferation and migration and decreased activity of the MAPK and mTOR pathways ( 138 ).…”