Abstracts 4. Gemeinsamer Jahreskongress der ... - SWISS KNIFE

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swissknife spezial 06 12.06.2006 13:39 Uhr Seite 50 30.08 T. Eugster 1 , T. Obeid 2 , L. Gürke 3 , P. Stierli 4 1 Gefässchirurgie, Universitätsspital Basel, 4031 Basel/CH, 2 Gefässchirurgie, Kantonsspital Aarau, Aarau/CH, 3 Gefässchirurgie, Universitätsspital Basel, Basel/CH, 4 Gefässchirurgie, Kantonsspital Aarau, Aarau/CH Follow-up 5 years after successful infrainguinal revascularisation Objective: Follow-up 5 years after successful infrainguinal revascularisation Background: 5 years after successful infrainguinal revascularisation with autologous vein future course remains unclear. Our prospective compiled database was checked for follow-up more than 5 years after revascularisation. Methods: Patency, revisions and death rate of all infrainguinal autologous revascularisations per-formed between 10-1998 and 12-2000 are compared. Results: 543 revascularisations were performed. After 5 years 176 reconstructions were patent and could be followed. Both groups, follow-up 5 years (n=176) have been compared. Failure rate (25% vs. 5%), major amputations (5% vs. 0%), death rate (26% vs. 14%) age (72 vs. 67 years) and diabetes (55% vs. 35%) were significantly more frequent among patients with follow-up less than 5 years. Conclusion: After five years of successful infrainguinal revascularisation with autologous vein further follow-up shows stable bypass function with only occasionally failure. Death rate is comparable with patients without peripheral arterial revascularisation. 50 swiss knife 2006; special edition 31 31.01 R.M. Baertschiger 1 , G. Mai 2 , P. Morel 3 , M. Armanet 1 , A. Sgroi 1 , D. Bosco 1 , V. Serre-Beinier 2 , C. Toso 1 , M. Hauwel 4 , M. Jaconi 4 , C. Gonelle-Gispert 2 , L. Bühler 2 1 Surgery, University Hospital Geneva, Cellular Isolation and Transplantation Laboratory, 1211 Genève/CH, 2 Surgery, University Hospital Geneva, Surgical Research Unit, 1211 Genève/CH, 3 Chirurgie Viscérale, Hôpital Cantonal de Genève, Genève/CH, 4 Faculty of Medicine, University of Geneva, Department of Pathology and Immunology, 1211 Genève/CH Xenotransplantation of mouse embryonic stem cells induces short term chimerism but not tolerance to xenogeneic skin grafts in rats Objective: Embryonic stem cells (ESC) are pluripotent cells derived from blastocysts that can be propagated indefinitely in vitro and can differentiate to all cell lineages both in vitro and in vivo, especially hematopoeitic cells. The aim of our study was to test in vivo the capacity of mouse ESC (mESC) to engraft in a xenogeneic recipient (rat), and to induce mixed hematopoietic chimerism and donor specific tolerance. Methods: We transplanted mouse embryonic stem cells (mESC), expressing blasticidin and GFP, intraportally into Sprague-Dawley (SD) rats, with or without immunosuppression Group 1: 12 rats were transplanted with 1 million mESC, without immunosuppression; Group 2: 12 rats were transplanted with 1 million mESC and received ciclosporin 20 mg/kg/d. Hematopoietic chimerism was analyzed weekly by FACS for mouse MHC class1 and CD3 on peripheral blood, and by PCR for blasticidin. At 3 months after mESC transplantation, skin grafts were performed from 129P2Ola/Hsd mice (syngeneic to mESC), from C57Bl/6 mice (xenogeneic third party), and from allogeneic Wistar rats. Results: At day 27 post-transplant, we detected circulating mouse MHC class1 positive cells in 4/12 animals of Group 1 (4-16%, mean 12%) and in 5/12 animals of Group 2 (6-36%, mean: 21%, p=0.28). Chimerism was confirmed by PCR. After day 27, no chimerism was detected and CD3 was always negative. At 3 months, skin grafts showed the following mean survival: Group 1: 129P2Ola/Hsd skin: 12 +/-2 days, C57Bl/6 skin: 19 +/- 7 days, allogeneic rat skin: 20 +/-5 days, Group 2: 129P2Ola/Hsd skin 15 +/- 4 days, C57Bl/6 skin: 17 +/-2 days, allogeneic rat skin: 16 +/- 0 days. When compared with each other in the same group, skin graft survival of various origin was not significantly different (p>0.18). Conclusion: We could detect circulating mouse cells in immunosuppressed and immunocompetent rats, after transplantation of mESC, without appearance of tumors or any other secondary effects. This transient chimerism did not induce tolerance to skin grafts. Immunosuppression with ciclosporin did not modify chimerism or outcome of skin grafts. Finally, these first results indicate that transplantation of xenogeneic ESC can induce short term chimerism without any modification of the recipient and improved protocols should be tested to prolong chimerism and allow tolerance. 31.02 D. Sidler 1 , S. Küpper 2 , P. Studer 3 , A. Kappeler 4 , J. Haier 2 , D. Candinas 5 , K. Stefan 6 , D. Inderbitzin 7 1 Department of Visceral and Transplantation Surgery, University Hsopital Bern, Bern/CH, 2 Department of General Surgery, University Hospital Münster, Münster/DE, 3 Department of Visceral and Transplantation Surgery, University Hsopital Bern, bern/CH, 4 Department of Pathology, University Hsopital Bern, Bern/CH, 5Vchk, Inselspital, Bern/CH, 6 Department of General Surgery, University Hsopital Münster, Münster/DE, 7 Department of Visceral and Transplantation Surgery, University Hospital Bern, 3010 Bern/CH Microvascular Changes in G-CSF-supported liver regeneration after partial hepatectomy in mice Objective: Previous studies have shown improved survival and augmented liver regeneration after partial hepatectomy in G-CSF-preconditioned animals. Little is known about molecular and biochemical mechanisms of this G-CSF effect. The aim of the study presented was to determine the effect of systemically administered granu-locyte colony stimulating factor (G- CSF) on the hepatic microvasculature during compensatory liver regeneration. Methods: Male Balb/c mice (n = 12) were preconditioned with either 5 g G-CSF or aqua ad injectabile subcu-taneously daily for 5 days. Subsequently, 60% partial hepatectomy was performed and daily injection of G-CSF or aqua ad injectabile continued. 48 hours postoperatively, intravital microscopy of the hepatic microvasculature was performed. After analyses, animals were sacrificed and remnant liver lobes and spleen were excised. Dry and moist weights were determined and samples were taken for immunohistological examination. Results: Moist and dry spleen weight was significantly augmented in GCSF-pretreated animals com-pared to control animals, indicating true splenomegaly and not only portal and/or cardiac congestion. No significant differ-ences were found in moist and dry remnant liver weights between the analyzed groups. Sinusoidal diameter was found to be significantly increased during intravital microscopy in G-CSF-pretreated animals (p < 0.01). Further-more, hepatic cell plate width was significantly increased after G-CSF-pretreatment (p < 0.01). No significant difference in the sinusoidal blood velocity was found between the two groups (p = 0.3). The Ki67 proliferation index was significantly increased in G-CSF pretreated animals compared to sham conditioned but resected control animals (p < 0.01). Conclusion: The presented analyses show significant changes in the hepatic microanatomy and vasculature in G-CSF treated animals during liver regeneration. This is the first study to elucidate potential mechanisms of G-CSF action during liver regeneration after partial hepatectomy. The presented results reveal a completely unexplored aspect of pharmacologically-supported liver regeneration and motivate further analyses. 31.03 M. Trochsler 1 , J. Plock 2 , S. Frese 3 , A. Keogh 4 , S. Knaden 5 , D. Erni 2 , J.F. Dufour 6 , D. Candinas 7 , D. Stroka 8 1 Klinik für Viszeral Und Transplantationschirurgie, Inselspital, 3010 Bern/CH, 2 Klinik für Plastische Chirurgie, Inselspital, Bern/CH, 3 Klinik für Thoraxchirurgie, Inselspital, Bern/CH, 4 Visceral Surgery, Inselspital Bern, 3010 Bern/CH, 5 Klinik für Viszeral und Transplantationschirurgie, Inselspital, Bern/CH, 6 Institute of Clinical Pharmacology, University of Bern, Bern/ CH, 7 Vchk, Inselspital, Bern/CH, 8 Clinic of Visceral and Transplantation Surgery, Inselspital, 3010 Bern/CH Temporary hepatic artery clamping activates hypoxia-inducible signaling pathways and upregulates hepatoprotective genes Objective: Molecular responses to hypoxia are initiated to restore oxygen homeostasis and to promote cell survival, and are mainly regulated through the activation of hypoxia-inducible transcription factors (HIF-1) and their target genes. In this study we questioned whether surgically depleting the liver’s arterial blood supply by clamping the hepatic artery (HA) was sufficient to mount a hypoxia-driven molecular response and the up-regulation of hepatoprotective genes. Methods: Microdialysis catheters were carefully introduced into the liver lobes of anesthetized, six week old male Balb/C mice. After a 1h stabilization period, the main HA was clamped using mi-crovascular surgical clips (hypoxia) or the portal triad in left liver lobe (ischemia) for 2h. The tissue saturated oxygen concentration SO2 was measured using an O2C surface probe (LEA-Medizintechnik) and microdialysis samples were taken every 30 min for 2h. Mice without HA clamping served as sham controls. Thirty minutes prior to the end of the experiment an ip injection of HypoxyProbe-1 (60 mg/kg) was administered and at the end point, the liver was carefully removed to avoid re-oxygenation of the tissue. Results: Within 30min of clamping the HA the SO2 of the liver decreased and remained at a low level for up to 2 hours. In comparision to sham operated animals, there was an increase of HypoxyProbe-1 staining without an associated increase of the lactate/pyruvate ratio or glycerol content in the interstitial fluid. Furthermore, we demonstrate the activation of the HIF signaling system by an increased stabilization of HIF-1 protein and by an up-regulation of EPO mRNA. And finally, we determined by real time PCR that in addition to HIF target genes, the hepatoprotective genes IL-6, IGFBP-1, HO-1 and A20 are up-regulated in HA clamped livers compared to sham operated controls. Conclusion: Our study demonstrates that a localized hypoxic stress and activation of hypoxiainducible signaling pathways can be achieved by temporarily removing the livers arterial blood supply without causing liver cell damage. Further we demonstrate that HA clamping is a potent regulator of molecular responses in the liver by the activation of hypoxia-inducible signaling pathways. Our findings offer an innovative approach to induce hepatoprotective genes to help defend the liver against subsequent damaging insults. 31.04 K. Furrer 1 , P. Dutkowski1, R. Graf 2 , P. Clavien 3 1 Swiss Hpb Center, Dept. of Visceral and Transplant Surgery, University Hospital of Zurich, 8091 Zurich/CH, 2 Dept. of Visceral and Transplant Surgery, University Hospital of Zurich, 8091 Zurich/CH, 3 Swiss Hpb Center, Dept. Visceral and Transplant Surgery, University Hospital of Zurich, 8091 Zurich/CH Novel short term hypothermic oxygenated perfusion (HOPE) system prevents injury in rat liver graft from non heart beating donor Objective: To assess a machine perfusion system to rescue liver grafts from non heart beating donors (NHBD). While extracorporeal perfusion systems may resuscitate liver metabolism from NHBD resulting in improved liver function upon reperfusion, the introduction of such strategy in the clinical routine depends on practicability criteria. We investigated, whether a novel rat liver machine perfusion applied after in situ warm ischemia and cold storage (mimicking the clinical situation of severe preservation injury) may rescue NHBD liver grafts. Methods: We induced cardiac arrest in male Brown Norway rats by phrenotomy and ligation of the heart base. No heparin was given before and during warm ischemia. We studied two experimental groups: 45 min. warm in situ ischemia + 5 hr cold storage (n=9) vs. 45 min. warm in situ ischemia + 5hr cold storage followed by 1 hr hypothermic oxygenated extracorporeal perfusion (HOPE) (n=9). In both groups, livers were reperfused in a closed isolated liver perfusion device for 3 hrs at 37 °C. Results: NHBD livers showed after cold storage and reperfusion necrosis of hepatocytes, increased release of AST (7.28 ï‚± 1.9 U/g liver wet weight) and decreased bile flow (0.17 ï‚± 0.1 ml/3hr). NHBD livers treated by HOPE showed no necrosis, intact sinusoidal endothelial cells, significantly less AST release (3.94 ï‚± 1.3 U/g liver wet weight) (p < 0.001) and increased bile flow (0.50 ï‚± 0.2 ml /3 hr) (p < 0.001). ATP was restored in livers treated by HOPE and severely depleted in cold stored NHBD livers. Conclusion: This study demonstrates effective prevention of injury by short termed oxygenated perfusion in a clinical highly relevant model of NHBD. Hypothermic oxygenated machine perfusion may serve as new tool for optimizing NHBD livers. 31.05 A. Laemmle 1 , M. Strehlen 2 , V. Roh 3 , M.M. Wagner 4 , J.F. Dufour 5 , B. Egger 6 , D. Stroka 7 , D. Candinas 6 , S.A. Vorburger 1 1 Visceral and Transplantation Surgery, University of Bern, 3010 Bern/CH, 2 Visceral and Transplantation Surgery, University of Bern, 3010 Bern Bern/CH, 3 Visceral Surgery, Inselspital, 3010
swissknife spezial 06 12.06.2006 13:39 Uhr Seite 51 Bern/CH, 4 Vchk, Inselspital, 3011 Bern/CH, 5 Institute of Clinical Pharmacology, University of Bern, Bern/CH, 6 Vchk, Inselspital, Bern/CH, 7 Clinic of Visceral- and Transplant Surgery, University Hospital of Berne, 3010 Berne/CH Tumor monitoring in animal models by the tissue inhibitor of metalloproteinases (TIMP-1) Objective: TIMP-1, a soluble 28kDa protein of the inhibitors of matrix metalloproteinases (MMP’s) family, has been shown to have additional tumor promoting activity. High serum levels of TIMP-1 in patients with colorectal cancer correlated with worse prognosis. This is why we evaluated if TIMP-1 could be used to monitor tumor growth in animal models. Methods: TIMP-1 levels of various colorectal cancer cell lines (SW620, CT26) have been determined in vitro by ELISA and Western blot. Tissue from colorectal and hepato-cellular cancer models (mice and rat) were tested for TIMP-1 expression by Imunohistochemistry (IHC), PCR and Western blot analysis. Ultimately, serum levels of TIMP-1, as determined by ELISA were compared with tumor size of sacrificed animals. Results: Whole cell lysates and supernatant from colorectal cancer cell cultures (human: SW 620, mouse: CT26) showed high levels of TIMP-1, which correlated with anti-tumor treatment. Tissue from a syngeneic orthotopic mouse model for peritoneal carcinosis showed treatment dependent expression of TIMP-1 in IHC and Western blot. Accordingly, serum levels of TIMP-1 in these mice correlated with tumor size of treated and control mice (r=0.74 and 0.758, Pearson). TIMP-1 serum levels of rats bearing Morris hepatoma liver tumors also correlated with tumor size at time of scarification (r=0.774). Conclusion: Serum levels of TIMP-1 may be used to monitor tumor growth and treatment response repeatedly without the need to sacrifice the animals. This method would allow to use orthotopic tumor models and reduce the amount of animals necessary to evaluate the efficacy of novel anti-tumor treatments. 31.06 M. Cikirikcioglu 1 , Y.B. Cikirikcioglu 1 , J. Tille 2 , A. Kalangos 1 , B.H. Walpoth 1 1 Department of Cardiovascular Surgery, University Hospital of Geneva, 1211 Geneva/CH, 2 Department of Clinical Pathology, University Hospital of Geneva, 1211 Geneva/CH Does size matter? Better endothelialisation in well matched ePTFE grafts Objective: Intimal hyperplasia and endothelialisation correlate inversely with shear stress and flow characteristics. Therefore, mismatch between native artery and graft diameter may affect intimal hyperplasia formation and endothelial coverage. The aim of this study is to compare mismatched (1 mm) and well matched (2mm) ePTFE grafts after implantation in the rat abdominal aorta with regard to angiographic dimensions and morphologic changes. Methods: In 16 male Sprague Dawley rats (415 ± 60 gr), 1 mm (n=8) and 2 mm ePTFE (n=8) grafts were interposed in the infrarenal abdominal aorta. The proximal and distal anastomoses were performed with 10/0 interrupted nylon sutures with an operative microscope. Anastomosis quality was evaluated intra-operatively with a transit time flowmeter. Animals were followed for 3 weeks and angiography was performed via right carotid artery before sacrifice. We measured midgraft, proximal and distal aorta diameters using quantitative abdominal aortography (QAA). Grafts were then harvested for computed morphometric analysis. Statistics were performed using Mann Whitney U test. Results: Intraoperative flow amounts were similar for two groups. After 3 weeks of implantation patency rate was 87% and 100% for 1 mm and 2 mm ePTFE grafts, respectively. Intimal hyperplasia was similar for both groups (11 ± 9 vs 10 ± 16 μm2/μm for 1 mm and 2 mm grafts, respectively) but endothelial coverage was significantly better in well matched 2 mm grafts (440 ± 233 vs 659 ± 239 μm for 1 mm and 2 mm grafts, respectively; p=0.008). Conclusion: In well-matched grafts we find a significantly better endothelialisation. This may influence long-term results despite early similar patency rates. 31.07 A. Demirag 1 , N. Guvener 2 , P. Morel 3 , S. Richter 4 , S. Deng 5 , C. Toso 6 , J. Philippe 4 , T. Berney 7 , J. Vallee 8 , L. Bühler 6 1 Surgery&transplantation, YED TEPE UNIVERSITY HOSPITALS, 34752 ISTANBUL/TR, 2 Endocrinology and Metabolism, Baskent University Hospital, ankara/TR, 3 Visceral/transplantation Surgery, Geneva University Hospitals, Geneva 14/CH, 4 Internal Medicine, University of Geneva, Geneva/CH, 5 Surgery, University of Pennsylvannia, Pennsylvannia/US, 6 Digestive Surgery and Transplantation, University of Geneva, Geneva 14/CH, 7 Visceral/transplantation Surgery, Geneva University Hospitals, 1211 Geneva/CH, 8 Radiology, University of Geneva, Geneva/CH Long-term effects of intra-hepatic islet auto- and allografts on liver parenchyma Objective: Liver is considered the optimal implantation site for islet grafts. Recent reports described periportal steatosis by magnetic resonance (MRI) in recipients of functioning islet allografts. No data exist on long-term effects of intra-hepatic islet auto- and allografts on liver parenchyma and no clear explanation for this phenomenon is available. The aim of the present study was to analyze liver parenchyma of patients previously transplanted with islet autoand allografts. Methods: Patients who underwent islet transplantation over a 12 years period were evaluated for the study. They were divided as Group 1 (allograft) and Group 2 (autograft). Islet function was assessed by daily insulin requirement, fasting and stimulated C-peptide, HbA1c at time of imaging. All patients were investigated by abdominal ultrasound, MRI, liver function tests, and lipid profile. Results: In Gr.1, steatosis was observed on MRI in 3/16 patients, and in Gr.2 in 3/6 patients. In Gr.1, patients with steatosis had higher basal (476vs.289 pmol/L, p85%), there was no significant difference between patients with or without steatosis. Conclusion: Hepatic steatosis can be associated with both islet auto- and allografts. In islet allograft recipients, steatosis was correlated to better graft function, and may be induced by a functional islet mass, i.e. paracrine effects of insulin released by transplanted islets on surrounding liver parenchyma. 31.08 I. Inci 1 , W. Zhai 1 , S. Arni 2 , S. Hillinger 2 , W. Weder 2 1 Department of Thoracic Surgery, University of Zurich, 8091 Zurich/CH, 2 Department of Thoracic Surgery, University of Zurich, Zurich/CH N-Acetyl cysteine attenuates ischemia-reperfusion injury after lung transplantation Objective: Early acute graft dysfunction continuous to be a problem after lung transplantation resulting in significant postoperative morbidity and mortality. The purpose of this study was to assess the protective effect of N-acetyl cysteine on post-transplant lung ischemia-reperfusion injury. Methods: Rat single-lung transplantation was performed in two (n=5) experimental groups after 18 hours of cold (4 C) ischemia. Group I animals consisted the ischemic control group. In group II, donor and recipient animals were treated with intraperitoneal injection of 150 mg/kg N-acetyl cysteine 15 minutes prior to harvest and reperfusion, respectively. After 2 hours of reperfusion, oxygenation was measured. Lung tissue was assessed for lipid peroxidation, neutrophil infiltration and reduced glutathione level. Peak airway pressure (PawP) was recorded throughout the reperfusion period. Results: N-acetyl cysteine treated group showed significantly better oxygenation (184.5 ± 83.3 mmHg versus 67.3 ± 16.4 mmHg, p=0.016), reduced lipid peroxidation (7.34 ± 1.9 micromol/g versus 17.46 ± 10.6 micromol/g, p=0.016). Lung tissue reduced glutathione levels in IC and NAC groups were 6.8±0.9 μM and 20.6±2.4 μM, respectively (p=0.004). Peak airway pressures at the end of the reperfusion period was 14.4±1.6 cm H2O in NAC group, and 19.2±2.2 cmH2O in IC group (p=0.008). Myeloperoxidase activity and wt to dry weight ratio not differ between the groups. Conclusion: In this model, exogenously administered N-acetyl cysteine effectively protected lungs from reperfusion injury after prolonged ischemia. 31.09 D.J. Schaefer 1 , O. Scheufler 1 , C. Jaquiery 1 , D.J. Wendt 2 , A. Braccini 2 , P. Ingold 3 , J.A. Gasser 3 , M. Jakob 4 , G. Pierer 1 , I. Martin 2 , M. Heberer 5 1 Reconstructive Surgery, University Hospital Basel, 4031 Basel/CH, 2 Surgical Research, University Hospital Basel, 4031 Basel/CH, 3 Musculoskeletal Diseases, Novartis Institutes for Biomedical Research, Basel/CH, 4 Orthopedic Surgery, University Hospital Basel, 4031 Basel/ CH, 5 Surgical Research and Hospital Management, University Hospital Basel, 4031 Basel/CH Size limits in autologous cell-based ectopic prefabrication of engineered bone flaps in rabbits Objective: Flap prefabrication and bone tissue engineering concepts could be combined to overcome limited availability and donor site morbidity of autologous bone flaps. In this study, we aimed at determining the depth of tissue ingrowth and bone tissue formation within an ectopic engineered bone flap model in rabbits. Methods: Autologous bone marrow stromal cells (BMSC) from 12 New Zealand White rabbits were expanded and uniformly seeded into two porous hydroxyapatite scaffolds (55 mio cells per 15 mm diameter, 30 mm height cylinder) using a perfusion bioreactor. One cell-scaffold construct was wrapped in a panniculus carnosus flap and covered by a semipermeable membrane (vascularized condition), whereas the second was only covered by the membrane and inserted under the contralateral panniculus carnosus, as control (non-vascularized condition). Constructs were explanted after 12 weeks and assessed by MRI, μCT and histology. Results: No connective or bone tissue formation were detected under non-vascularized conditions. Under vascularized conditions, constructs were filled by vascularized connective tissue in the outer 4.2 ± 0.3 mm and contained bone tissue in the outer 2.5 ± 0.3 mm, resulting in significant differences in all histomorphometric parameters assessed. Conclusion: A panniculus carnosus flap supported ectopic prefabrication of large engineered bone flaps in rabbits. The finding that bone tissue was restricted to the outer region of the flaps could be explained by insufficient vascularization of the central core of the constructs upon implantation and prompts for the development of strategies to improve vessel ingrowth from the flap. 32 32.01 D. Schmidt 1 , A. Mol 2 , C. Breymann 3 , B. Odermatt 4 , M. Gössi 5 , R. Prêtre 6 , M. Genoni 7 , G. Zund 8 , S.P. Hoerstrup 8 1 Klinik für Herz-und Gefässchirurgie, UniversiätsSpital Zürich, 8091 Zürich/CH, 2 Department of Biomedical Engineering, Eindhoven University of Technology, The Netherlands, Eindhoven/NL, 3 Department of Gynaecology and Obstetrics, University Hospital, Zurich, Switzerland, 8091 Zürich/CH, 4 Institute for Clinical Pathology, UniversiätsSpital Zürich, 8091 Zurich/CH, 5 Institute of Polymers, ETH, 8091 Zürich/CH, 6 Congenital Cardiovascular Surgery, University Children's Hospital Zürich, Zürich/CH, 7 Herz Chirurgie, Stadtspital Triemli, 8063 Zürich/CH, 8 Klinik für Herz-und Gefässchirurgie, UniversiätsSpital Zürich, Zürich/CH A novel concept: engineering of living autologous pediatric cardiovascular tissue replacements using prenatal progenitors Objective: Here, a novel concept using human prenatal progenitor cells for cardiovascular engineering is presented, in order to generate living autologous implants with the potential of growth, remodeling and regeneration for the repair of congenital malformation ready to use at birth. Methods: Prenatal progenitor cells were isolated from either placenta, Wharton’s jelly or cord blood. After differentiation and characterization cells were expanded in vitro. For fabrication of cardiovascular tissues, biodegradable scaffolds (PGA/P4HB) were seeded with either placenta-derived cells or with Wharton’s Jelly-derived cells. Constructs were implanted in an in vitro perfusion-strain bioreactor and exposed to biochemical and/or mechanical stimulation. After 21d, the surfaces of constructs were endothelialized with blood-derived EPC and cultured for additional 5d. Tissue formation was analyzed by histology, immunohistochemistry, and scanning electron microscopy. Extracellular matrix elements and cell amount were quantified by biochemistry. swiss knife 2006; special edition 51
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