287 RENAL BENEFIT OF RAPAMYCIN IN PEDIATRIC HEART TRANSPLANT PATIENTS I.C.Balfour,S.W.Srun,E.G.Wood,C.W.Belsha,D.L. Marshall, B.R.Ferdman,Department of Pediatrics, Saint Louis University School of Medicine, Saint Louis,MO Background: Calcineurin inhibitors (CNI) are effective in prevent- ing rejection in recipientsof solid organ transplants, but these agents are nephrotoxic. Rapamycin (RAPA) when used in conjunc- tion with CNI, allows a lower dose of CNI to be used,potentially reducing renal damage. Pediatric heart transplant patients (Pts) were studied to determine if their renal function improved after initiating RAPA. Methods: RAPA was started in 15 pts with reduced (10) or no CNI (5). We studied renal and other parameters before and after RAPA was started. Pts were 4.1 5.7 yrs old (mean 1 standard deviation) at transplant (median 0.4 yrs) and 10.3 4.6 yrs old when switched to RAPA (median 9.2 yrs), 10 were male. Indications for RAPA were worsening renal function (10), to improve adherence (2), change in protocol (2), post transplant lymphoproliferative disease (1). The pre and post RAPA data were compared using a paired-samples T-test. Results: At 30 days after RAPA the calculated creatinine clearance (Schwartz formula) increased from 88 28 ml/min/1.73M 2 to 105 27, p .008. None of the patients had rejection after RAPA. Conclusion: Renalfunction appears to improve in the short term after starting RAPA and lowering CNI dose. RAPA may be beneficial in preserving renal function in pediatric heart transplant pts. 288 INTRAVENOUS STEROIDS DO NOT INCREASE PERIOPERATIVE AIRWAY COMPLICATION RISK IN PEDIATRIC LUNG TRANSPLANT PATIENTS J. Nigro, 1 M.V.Horn, 1 V.A.Starnes, 1 M.L.Barr, 1 M.S.Woo, 1 1 Cardiothoracic Surgery, Childrens Hospital Los Angeles, Los Angeles, CA Does IV steroid use during the 1st week after lung transplant surgery increase the risk of airway complications? Some centers advocate using induction therapy and then holding steroids from Day 2 thru Day 7. However, use of induction therapy carries increased infection risk and expense.To determine ifairway complications (airway dehiscence)are associated with IV steroid use in the immediate post-transplant period,we performed a retrospective review of all lung transplantations performed at our center. Heart-lung transplant recipientswere excluded from analysis. Data collected:pt age, primary diagnosis, type of transplant(cadaveric orliving donor), airway culture resultsprior to transplant,occurrence ofairway complications (dehiscence, poor wound healing, prolonged air leak, etc),pre-transplant use ofsteroids (dose /length of time),and any perioperative mortality due to airway complications. None of these patients received inducation therapy. All pts received IV methylpred- nisolone with an initial dose of 10 mg/kg coming off the pump and then 5 mg/kg/dose q 8H x 3 doses (max 125 mg/dose). For the next 3–5 days, the IV methylprednisolone dose is 0.5 mg/kg/dose q 12H. Steroid dose is weaned by 0.1 mg/kg/day with the aim of achieving 0.5 mg/kg/day by 1 month post-transplant. During the study period from Aug 2003 through Sept 2004, 71 patients (age 13.24.9yrs; 52 CF, 14 PH, 5 pts with non-purulent lung disease) have undergone 74 bilateral lung transplant procedures (3 redos; 51 living donor and 23 cadaveric) at our center. 1 pt, who had been on high-dose steroids for 10 yrs had an air leak noted in the immediate perioperative period and wentback to the OR for successful surgicalrepair.Thus,the incidence ofairway deshiscence was only 1%. There was no pro- longed air leak in any patients. There have been no deaths due to airway complications. We conclude thatdaily use ofIV steroids during the first post-operative week does not cause significant airway complications in lung transplant recipients. 289 AUTOLOGOUS TISSUE ENGINEERED WITH MESENCHYMAL STEM CELLS FOR CARDIAC REPAIR AFTER MYOCARDIAL INFARCTION IN RATS: FEASIBILITY AND HISTOLOGICAL DATA P. Maureira, 1 J. Nloga, 1 Y. Grignon, 2 Y. Li, 1 T. Lacrouts, 1 F. Groubatch, 1 J.F. Stoltz, 3 J.P. Villemot, 1 N. Tran, 1 1 Laboratory of School Surgery, Faculty of Medicine-Nancy, Nancy,France; 2 Laboratory of Pathology, University Hospital Center of Nancy, Nancy,France; 3 Department of Cell Therapy and Tissue Engineering, UMR-CNRS 7563, Faculty of Medicine-Nancy, Nancy, France Introduction: In chronic stage after myocardial infarction (MI) with extensive fibrous deposition and LV thinning process, in vitro engi- neered cardiac tissues provide new materials for in vivo cardiac surgery repair. We investigated whether the cardiac engraftment of autologous tissue engineered with bone marrow mesenchymal stem cells (BMSCs) would incorporate into the chronic ischemic myocar- dium and then promote angiogenesis. Methods: Artificial tissue (AT) samples were engineered by seeding rat BrdU labelled-BMSCs with 3-dimentional collagen matrix. Two weeks after tissue culture, circular ATs (1mm thick, 1mm high, 10mm diameter) were sutured into the scar areas of 1-mo coronary ligated rat hearts (n 12). Results: One month after grafft, histological studies have shown that AT survived and completly incorporated into the damaged myocar- dium. Planimetry has monstrated no change in LV chamber diameter but an enhance in the LV thickness (P0.05 vs MI rats,n 12). Furthermore, immunohistochemical studies have demonstrated that angiogenesis was drammatically increased within the grafted areas and neovessels were stained positively with both BrdU and CD31. Other cellcomponent in AT graft formed multiple cell layers with myofribroblastic phenotype. No evidence ofnew cardiomyocytes were detected in the grafted areas. Conclusions: We provide the first evidence for the general feasibility of BMSCs engineered tissue as material for a novel autologous tissue replacement strategy. The use of myocytes derived BMSCs as a step forward to cardiac tissue engineering might be a promising approach to reconstitute degenerated tissue. 290 IN VIVO LOCATION OF INTRAMYOCARDIAL IMPLANTED 111 IN-OXINE LABELED MESENCHYMAL STEM CELLS: ASSESSEMENT WITH DUAL ENERGY PINHOLE 99m TC-SESTAMIBI SPECT IN A RAT MODEL OF MYOCARDIAL INFARCTION N. Tran, 1,2 F. Maskali, 3 P. Franken, 4 J. Nloga, 1 T. Lahoutte, 4 P. Maureira, 1 Y. LI, 1 P.Y. Marie, 3 G. Karcher, 3 J.F. Stoltz, 2 BUN Cr Hb WBC Kⴙ Mgⴙⴙ Pre-RAPA 27.1 12.4 1.0 0.5 11.5 1.7 5.9 2.1 5.2 0.5 1.6 0.2 30 days post RAPA 18.6 11.1* 0.8 0.3** 12.0 1.3 7.7 3.5 4.5 0.6*** 1.3 0.4**** p *0.014 **0.019 ***0.010 ****0.049 S136 Abstracts The Journal of Heart and Lung Transplantation February 2005