title: Enhancement of vascular endothelial growth factor's angiogenic capacity by the therapeutic modulation of notch signalling improves tram flap survival in rats submitted to nicotine.
abstract: BACKGROUND
  Smoke of cigarettes, and specifically nicotine, has been shown to diminish pedicled transverse rectus abdominis musculocutaneous (TRAM) flap survival. Considering that Notch signalling through its ligand Delta-like 4 (Dll4) functions as anti-angiogenic factor by inhibiting the pro-angiogenic effects of vascular endothelial growth factor (VEGF), it is hypothesised that inhibition of the Notch would promote angiogenesis and increase TRAM flap survival in rats submitted to nicotine.
  
  
  METHODS
  Twenty rats were treated with nicotine for 28 days preoperatively. Thereafter, a pedicled TRAM flap was created in all animals. The Notch inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine-t-butyl-ester was administered in animals of the treatment group. Animals in the control group were given the same amount of solvent. Five days after the surgery, viable flap areas were determined. Skin samples were evaluated for VEGF and Dll4 mRNA levels. Immunohistochemical analysis was used for the assessment of endothelial Dll4 expression. Vascular density was determined histologically. Plasma levels of VEGF and Dll4 were measured.
  
  
  RESULTS
  A significant improvement in TRAM flap surviving area was observed in the treatment group (53.50 ± 14.25%) compared with the controls (32.20 ± 9.15%). Immunohistochemical analysis revealed a significant increase in the number of Dll4 stained vessels in animals of the treatment group (9.2 ± 1.6) in comparison with the controls (5.7 ± 1.9). VEGF mRNA levels (0.22 ± 0.08) in the treatment group were significantly lower than those in the control group (0.36 ± 0.09).
  
  
  CONCLUSIONS
  Notch inhibition significantly improved TRAM flap survival in animals exposed to nicotine by promoting VEGF-induced angiogenesis.
authors.affiliation: a Faculty of Medicine, Department of Plastic, Reconstructive and Aesthetic Surgery , Ahi Evran University , Kırşehir , Turkey.
authors.forename: Ozan Luay
authors.identifier: http://orcid.org/0000-0003-0410-1215
authors.initials: OL
authors.lastname: Abbas
authors.affiliation: b Faculty of Medicine, Department of Medical Genetics , Başkent University , Ankara , Turkey.
authors.forename: Yunus Kasım
authors.initials: YK
authors.lastname: Terzi
authors.affiliation: c Faculty of Medicine, Department of Histology and Embryology , Ahi Evran University , Kırşehir , Turkey.
authors.forename: Orhan
authors.initials: O
authors.lastname: Özatik
authors.affiliation: d Faculty of Medicine, Department of Pharmacology , Ahi Evran University , Kırşehir , Turkey.
authors.forename: Fikriye Yasemin
authors.initials: FY
authors.lastname: Özatik
authors.affiliation: e Faculty of Medicine, Department of Biochemistry , Ahi Evran University , Kırşehir , Turkey.
authors.forename: Gamze
authors.initials: G
authors.lastname: Turna
authors.affiliation: e Faculty of Medicine, Department of Biochemistry , Ahi Evran University , Kırşehir , Turkey.
authors.forename: Rukiye
authors.initials: R
authors.lastname: Nar
authors.affiliation: f Faculty of Medicine, Department of Biostatistics , Osmangazi University , Eskişehir , Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Musmul
mesh_terms: D000818:Animals; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D006085:Graft Survival / Q000187:drug effects*; D047908:Intracellular Signaling Peptides and Proteins / Q000097:blood / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000097:blood / Q000378:metabolism; D023421:Models, Animal; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D051880:Receptors, Notch / Q000187:drug effects / Q000378:metabolism; D013524:Surgical Flaps / Q000098:blood supply* / Q000473:pathology; D042442:Vascular Endothelial Growth Factors / Q000097:blood / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051880:Receptors, Notch; D042442:Vascular Endothelial Growth Factors; C064045:delta protein; D009538:Nicotine
keywords: Dll4; Notch; TRAM; angiogenesis; nicotine; survival