EPO reverses defective wound repair in hypercholesterolaemic mice by increasing functional angiogenesis.
This study aims to elucidate the effect of erythropoietin (EPO) on the microcirculation during wound healing in mice genetically depleted of apolipoprotein E (ApoE(-/-)). The skinfold chamber in mice was used for intravital microscopy, whereby an incisional wound was created within the chamber. Animals received Recormon(®) 1000 U kg(-1) body weight (BW) intra-peritoneally (i.p.) at day 1, 3, 5, 7, 9 and 11 post-wounding at a concentration of 100 Uml(-1) (n=42). Normal healing and vehicle-treated wild type animals (WT) served as controls. The microcirculation of the wound was analysed quantitatively in vivo using epi-illumination intravital fluorescence microscopy. Microtomography (micro-CT) analysis of casted wound microvessels was performed allowing three-dimensional (3D) histomorphometric analysis. Tissue samples were examined ex vivo for wound scoring and for expression analysis of EPO-Receptor (Epo-R) and endothelial nitric oxide synthase (eNOS). Upon EPO treatment, the total wound score in ApoE(-/-) mice was increased by 23% on day 3, by 26% on day 7 and by 18% on day 13 when compared to untreated ApoE(-/-) mice (all P<0.05 vs. vehicle). Improved wound healing was accompanied with a significant increase of functional angiogenetic density and angiogenetic red blood cell perfusion on days 5, 7, 9 and 11 post-wounding. 3D histomorphometric analysis revealed an increase of vessel thickness (1.7-fold), vessel volume (2.4-fold) and vessel surface (1.7-fold) (all P<0.05 vs. vehicle). In addition, improved wound healing was associated with enhanced Epo-R expression (4.6-fold on day 3 and 13.5-fold on day 7) and eNOS expression (2.4-fold on day 7) (all P<0.05 vs. vehicle). Our data demonstrate that repetitive systemic EPO treatment reverses microvascular dysfunction during wound healing in hypercholesterolaemic mice by inducing new vessel formation and by providing the wound with more oxygen.
Division of Plastic and Reconstructive Surgery, Department of Surgery, University Hospital Zurich, CH-8091 Zurich, Switzerland.
Ahmed
A
Elsherbiny
Dominik C
DC
Högger
Meisam Khorrami
MK
Borozadi
Christian A
CA
Schmidt
Jan
J
Plock
Rene D
RD
Largo
Nicole
N
Lindenblatt
Pietro
P
Giovanoli
Claudio
C
Contaldo
D000818:Animals; D004921:Erythropoietin / Q000494:pharmacology*; D007124:Immunoenzyme Techniques; D051379:Mice; D008833:Microcirculation / Q000187:drug effects*; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D014945:Wound Healing / Q000187:drug effects*; D055114:X-Ray Microtomography
D011994:Recombinant Proteins; C103998:epoetin beta; D004921:Erythropoietin; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse