A new total hemiface allotransplantation model in rats.

INTRODUCTION: Vascularized composite allotransplantation (VCA), a new reconstructive option for patients suffering from extensive facial defects leads to superior functional and aesthetic outcomes compared to the standard autologous reconstruction. Among VCA recipients, each case involves different facial structures and tissues depending on the patient's injury, thus drawing conclusions on the mechanism of immune interactions between the donor and recipient is challenging. This study introduces a new total hemiface VCA model, including scalp, external ear, mystacial pad, premaxilla, upper/lower lids, nose, and upper/lower lips to evaluate the effect of transplantation of multitissue VCA on the recipient's immune response. MATERIAL AND METHODS: Ten hemiface allotransplantations were performed in two groups between Lewis-Lewis (isograft) and LBN-Lewis (allograft) rats. Cyclosporine A (CsA) monotherapy was applied in the allograft group to prevent rejection. RESULTS: All flaps survived up to 100 days post-transplant. The mean warm ischemia time was 45 minutes. Histological analysis revealed normal bone, cartilage (ear and nose), conjunctiva, palpebra, and eyelashes. Flow cytometry confirmed donor-specific chimerism for T cells (CD4/RT1(n) and CD8/RT1(n)) and B cells (CD45RA/RT1(n)) in the peripheral blood of all rats in the allotransplantation group. At post-transplant day 7, chimerism levels were at 1.68% for CD4/RT1(n) , 0.46% for CD8/RT1(n) and 0.64% for CD45RA/RT1(n). However, chimerism levels for CD4/RT1(n), CD8/RT1(n), and CD45RA/RT1(n) populations decreased at long-term follow-up (at post-transplant day 100) to 0.08%, 0.04%, and 0.23%, respectively. CONCLUSION: The feasibility and long-term survival of the new hemiface VCA transplantation model was confirmed, donor-specific chimerism and post-transplant tissue changes were evaluated.

Pre- and postischemic pulsed acoustic cellular expression conditioning modulates expression of inflammation factors in cremaster ischemia/reperfusion injury model.

Pulsed acoustic cellular expression (PACE) is a treatment that applies focused acoustic shock waves to promote tissue healing. The aim of this study was to assess the effect of PACE treatment on inflammatory responses in a cremaster muscle ischemia/reperfusion injury model. Seventeen cremaster muscle flaps were evaluated in four groups: nonischemic controls (n = 5), 5-hour ischemia controls (n = 4), preischemic (5-hour) PACE conditioning (n = 4), and postischemic (5-hour) PACE conditioning (n = 4). The expression of proinflammatory cytokines (TNFα, IL-6, IL-1α, IL-1ß, GM-CSF) and chemokines (CCL3, CCL4, CXCL4) was assessed using TaqMan® real-time PCR. Expression of ELAM-1, VCAM-1, and ICAM-1 was assessed by immunostaining. Preischemic PACE conditioning upregulated expression of IL-6, CCL3, CCL4, and CXCL4, and downregulated expression of TNFα, GM-CSF, and IL-1α. Postischemic PACE conditioning significantly decreased expression of all evaluated genes. Pre- and postischemic PACE conditioning decreased expression of ELAM-1 and ICAM-1. Results of the study indicate that application of PACE conditioning may have a beneficial effect on the recovery of tissues subjected to the ischemia/reperfusion injury. Postischemic PACE conditioning revealed anti-inflammatory effect as confirmed by decreased expression of inflammatory cytokines, chemokines, and cell adhesion molecules (ELAM-1 and ICAM-1) that are responsible for leukocyte recruitment into ischemic tissues. Hence, PACE therapy may be used effectively in clinical practice as a convenient therapeutic strategy to protect tissues against ischemia/reperfusion related injury after microsurgical procedures of free tissue transfers.