Aging effects on pedicled fasciocutaneous flap survival in rats.

ABSTRACT

BACKGROUND: Poorer surgical outcomes in older patients undergoing locoregional head and neck reconstruction have raised questions about tolerance of aging tissue to iatrogenic ischemic insults. METHODS: We examined the effects of aging on viability of pedicled composite flaps in 2-month and 6-month old Sprague-Dawley male rats and correlated flap survival with vascular endogenous growth factor (VEGF) and VEGF receptor 2-mediated signaling events. Flap segments were assessed for gross/cellular necrosis by optical microscopy and for proangiogenic, apoptotic, and proliferative protein-marker content. RESULTS: Flap necrosis significantly increased with age (4.2% in young vs 49.17% in old), correlating with reduced expression of VEGF, inhibition of signal transducer and activator of transcription 3 (STAT3), and Akt activation, impaired Akt-dependent endothelial nitric oxide synthase (eNOS) phosphorylation, elevated Bax/Bcl-2 ratio, activation of Caspase-3, upregulated nuclear poly (ADP-ribose) polymerase-1 (PARP-1) cleavage and lower proliferating cell nuclear antigen (PCNA) levels. CONCLUSION: Pedicled flap survival is higher in younger rats in part because of unhindered expression of VEGF and enhanced activity of cell survival and promigratory signaling pathways. © 2015 Wiley Periodicals, Inc. Head Neck 38 E1152-E1162, 2016.