title: Sildenafil increases endothelial progenitor cell function and improves ischemia-induced neovascularization in hypercholesterolemic apolipoprotein E-deficient mice.
abstract: Hypercholesterolemia is associated with impaired neovascularization in response to ischemia. Potential mechanisms include defective NO bioactivity and a reduction in the number/function of endothelial progenitor cells (EPCs). Here we tested the hypothesis that sildenafil, a phosphodiesterase 5 inhibitor that increases NO-driven cGMP levels, could stimulate EPC function and improve ischemia-induced neovascularization in hypercholesterolemic conditions. Apolipoprotein E-deficient (ApoE(-/-)) mice were treated (or not treated) with sildenafil (40 mg/kg per day in water), and hindlimb ischemia was surgically induced by femoral artery removal. Sildenafil treatment led to an improved blood flow recovery, an increased capillary density, and a reduction of oxidative stress levels in ischemic muscles at day 7 after surgery. Sildenafil therapy is associated with an increased activation of angiogenic transduction pathways, including Akt, p44/42 mitogen-activated protein kinase, and p38. In vitro, sildenafil increases cellular migration and tubule formation of mature endothelial cells (human umbilical vascular endothelial cells) in a cGMP-dependent manner. In vivo, ApoE(-/-) mice treated with sildenafil exhibit a significant increase in the number of bone marrow-derived EPCs. Moreover, the angiogenic activities of EPCs (migration and adhesion) are significantly improved in ApoE(-/-) mice treated with sildenafil. In summary, this study demonstrates that sildenafil treatment is associated with improved ischemia-induced neovascularization in hypercholesterolemic ApoE(-/-) mice. The mechanisms involve beneficial effects on angiogenic transduction pathways together with an increase in the number and the functional activity of EPCs. Sildenafil could constitute a novel therapeutic strategy to reduce tissue ischemia in atherosclerotic diseases.
authors.affiliation: Department of Cardiovascular Research, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Dussault
authors.forename: Fritz
authors.initials: F
authors.lastname: Maingrette
authors.forename: Catherine
authors.initials: C
authors.lastname: Ménard
authors.forename: Sophie-Elise
authors.initials: SE
authors.lastname: Michaud
authors.forename: Paola
authors.initials: P
authors.lastname: Haddad
authors.forename: Jessika
authors.initials: J
authors.lastname: Groleau
authors.forename: Julie
authors.initials: J
authors.lastname: Turgeon
authors.forename: Gemma
authors.initials: G
authors.lastname: Perez
authors.forename: Alain
authors.initials: A
authors.lastname: Rivard
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency*; D015153:Blotting, Western; D002097:C-Reactive Protein / Q000032:analysis; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D006614:Hindlimb / Q000098:blood supply; D006937:Hypercholesterolemia / Q000503:physiopathology; D007150:Immunohistochemistry; D007511:Ischemia / Q000188:drug therapy; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D010879:Piperazines / Q000494:pharmacology*; D011336:Probability; D011687:Purines / Q000494:pharmacology; D011897:Random Allocation; D000068677:Sildenafil Citrate; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism; D013450:Sulfones / Q000494:pharmacology*
chemical_list: D001057:Apolipoproteins E; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D002097:C-Reactive Protein; D000068677:Sildenafil Citrate