emia) or insulin + L-NAME (100 mM, a NO synthase inhibitor, 60 min. prior to ischemia) intravenously. Pulmonary microvascular dysfunction was quantitated by measuring the concentration of Evans Blue Dye (EBD) within the lung following the intravenous administration of 20 mg/kg EBD. Statistical signiﬁcance was determined using a one-way ANOVA with a Bonferroni post-hoc test. The concentration of EBD within the lungs of mice undergoing I/R was nearly twice that of SHAM operated animals (p  0.01, SHAM vs. I/R); this effect was prevented by the administration of insulin (p  0.05, I/R + insulin vs. I/R). Inhibition of NOS with L-NAME abolished insulin’s beneﬁcial effect (p  0.05, I/R + insulin vs. I/R + insulin + L-NAME). In the absence of I/R, insulin or L-NAME alone had no effect on pulmonary EBD concentration (data not shown). Intestinal I/R causes pulmonary microvascular barrier dysfunction which is prevented by insulin pretreatment. As in our in vitro studies on oxidant-stressed endothelial cells, this protective effect was dependent upon the activity of nitric oxide synthase. These data suggest that insulin’s protective effect on endothelial barrier function during pro-inﬂammatory states is related to insulin’s known stimulatory effect on endothelial nitric oxide release. Experimental Groups (n = 10) mg EBD/g lung tissue SHAM 0.9  0.2 I/R 1.7  0.2* I/R + insulin 0.9  0.3# I/R + insulin + L-NAME 1.6  0.2*** *p  0.01 vs. SHAM **p  0.05 vs. I/R + insulin #p  0.05 vs. I/R 142. TISSUE ENGINEERED, BILAYERED LIVING SKIN SUBSTITUTE (APLIGRAF®) PREVENTS CONTRAC- TION IN ACUTE EXCISIONAL WOUNDS. Sheikh AY, RollinsMD, Hendry SL, Pearl JI, Pelletier MP, Robbins RC, Hopf HW, Hunt TK; Stanford University Introduction: Recently, a number of tissue engineered living skin substitutes (LSSs) have become available for clinical use. Limited data exist regarding the efﬁcacy of such products for treatment of acute wounds (e.g. burns, trauma-related dermal- avulsion). The extent to which LSSs might prevent adverse heal- ing sequelae such as contractures remains to be established. Hy- perbaric oxygen (HBO) therapy is an accepted tool used to promote skin graft take, and whether such therapy can be used in concert with LSSs has not been tested. We evaluated the efﬁcacy of a widely used clinical LSS (Apligraf®) using a murine excisional wound model both as a stand alone therapy and with adjuvant HBO treatment. Methods: Apligraf® (Organogenesis, Canton, MA) LSS is a bilayered construct, with human ﬁbroblasts embed- ded in bovine type I collagen serving as a dermal equivalent upon which a human keritinocyte-derived epidermis is grown. Full- thickness, excisional wounds were created on the dorsum of adult, female Swiss Webster mice (n=42). Animals were randomized to 3 groups (n=14/group): control (Xeroform dressing alone), LSS, or LSS+HBO therapy. All wounds were created using a 1.5 1.5 cm 2 template, and LSS or Xeroform was applied, followed by a circum- ferential bandage to prevent disruption of the wound. HBO treat- ment was carried out at 2 ATA, 90 minutes, BID for 7 days. Digital images of the wounds were obtained at days 5, 10, 15, and 20 following wounding and total wound area was quantiﬁed in a double blinded-fashion using NIH image software. Histology was performed on dermal specimens harvested at day 20. Statistical signiﬁcance was set at p0.01 using the Kruskal-Wallis non- parametric method with Dunn’s post-hoc test. Results: As wound area decreased over the 20 day study, both LSS-treated groups exhib- ited signiﬁcantly (p0.01) decreased wound contraction (percentage of original wound area) on days 5, 10, 15, and 20 compared to control (see graph). By day 20, percentage of original wound areas were: control- 13.19.3; LSS-55.218.6; LSS+HBO- 61.6 12.2 (p0.01, versus control). Microscopic evaluation of the wounds at day 20 using H&E and lechtin staining did not reveal endothelial pene- tration into the LSS in any group. Conclusions: LSSs have become part of the clinical armamentarium for acute wounds that require coverage where donor graft may be limited. We found that LSS-treatment prevents acute wound contraction signiﬁcantly, suggesting a therapeutic role for instances where wound contrac- ture may present a problem (e.g. wounds involving the face or joints). Furthermore, HBO therapy did not adversely affect this inhibitory property, and did not increase host endothelial pene- tration into the LSS. Further studies are warranted to establish optimal strategies for effective use of LSS in acute wounds. 143. MODULATING LOCAL DERMAL INFLAMMATORY RE- SPONSE IMPROVES SURVIVAL IN A POST-BURN PNEUMONIA MODEL. S. Arbabi, K. R. Ipaktchi, A. Mattar, A. D. Niederbichler, M. R. Hemmila, G. L. Su, S. C. Wang; University of Michigan, Ann Arbor, MI. Objective: Infectious complications following burn injury, such as pneumonia, are associated with a signiﬁcant increase in morbidity and mortality. We previously demonstrated that post-burn modula- tion of dermal inﬂammatory signaling effectively attenuated sys- temic inﬂammatory response and burn-induced lung injury. Dermal inﬂammation was reduced by application of a topical inhibitor of p38 MAPK, a pivotal stress signaling pathway, to the burned skin. We now hypothesize that post-burn inhibition of dermal inﬂammatory signaling will improve survival in a second-hit pneumonia model. Methods: C57/Bl6 mice underwent 30% TBSA scald burn. Animals were then treated with topical SB202190 (SB), a p38 inhibitor, or vehicle. There were 3 experimental groups: 1- sham animals which were not burned (Sham), 2- burned animals treated with vehicle only (Burn), and 3- burned animals treated with topical p38 inhibitor which was applied to the burned area (Burn+SB). The next day all animals, including sham, underwent intratracheal innoculation with Klebsiella pneumoniae. Animals were then observed for a week. Results: On the post-burn day one, before bacterial innoculation, the Burn+SB group had a signiﬁcant reduction in proinﬂammatory cy- tokine levels (IL-6 and TNF-), both locally in skin and systemically in lungs, as compared to Burn alone. This was associated with a reduction in microvascular damage and improvement in pulmonary function testing. After intratracheal instillation of bacteria, there was signiﬁcant improvement in survival in the Burn+SB group as compared to burn alone (p=0.01), as the graph demonstrates. This graph is a representative of three separate experiments with total of 25 animals in each experimental group. Conclusion: Post-burn attenuation of the local inﬂammatory signaling by a topical p38 inhibitor improves outcomes in a second-hit pneumonia model. Ap- plication of topical inhibitors of inﬂammatory signaling may act as an effective “source control”, decreasing post-burn local response that may be driving the over-stimulation of the systemic inﬂamma- tory response. These ﬁndings open a new approach to burn therapy targeting primary local and secondary systemic pathology. 214 ASSOCIATION FOR ACADEMIC SURGERY AND SOCIETY OF UNIVERSITY SURGEONS—ABSTRACTS