Abstracts 4. Gemeinsamer Jahreskongress der ... - SWISS KNIFE
Abstracts 4. Gemeinsamer Jahreskongress der ... - SWISS KNIFE
Abstracts 4. Gemeinsamer Jahreskongress der ... - SWISS KNIFE
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swissknife spezial 06 12.06.2006 13:39 Uhr Seite 37<br />
rative dietary supplementation with n-3 PUFAs protects macrosteatotic livers against ischemic<br />
injury via improving microcirculation. However, protective strategies applied during or<br />
after ischemia are unlikely to be successful.<br />
17.12<br />
M. Cikirikcioglu 1 , G. Bowlin 2 , Y.B. Cikirikcioglu 1 , J. Tille 3 , A. Kalangos 1 , B.H. Walpoth 1<br />
1 Department of Cardiovascular Surgery, University Hospital of Geneva, 1211 Geneva/CH,<br />
2 Biomedical Engineering, Virginia Commonwealth University, Virginia/US, 3 Department of<br />
Clinical Pathology, University Hospital of Geneva, 1211 Geneva/CH<br />
Degradable synthetic (PDS-based) electrospun scaffolds: assessment as an arterial graft in<br />
the rat model<br />
Objective: Vascular tissue engineering necessitates a degradable scaffold. The purpose of<br />
this study was to evaluate biocompatibility and thrombogenicity of electrospun polydioxanone(PDS)<br />
grafts.<br />
Methods: Electrospun PDS was selected because of biomechanical strength, surgeon’s<br />
handling, degradation, cellular ingrowth and tissue reaction in a subcutaneous implantation<br />
model. In 15 Sprague Dawley rats, 1-mm e-PTFE grafts (n=6) and 1-mm PDS grafts (n=9)<br />
[bare, external wrapped or mixed with poly(lactic acid) (PLA)] were interposed in the infrarenal<br />
abdominal aorta. Terminal digital substraction angiography was performed for patency<br />
assessment and grafts were harvested for morphologic as well as scanning electron microscopic<br />
examination.<br />
Results: At three weeks, PDS showed comparable patency rates (overall, 89%) to e-PTFE<br />
grafts (83%). However, saccular aneurysm formation was found in all unwrapped patent PDS<br />
grafts. This was prevented with external wrapping (3 grafts were wrapped with non-degradable<br />
woven matrix, e-PTFE or external electrospun nylon) or blend of PDS with PLA (n=3). At 6<br />
and 12 weeks patency was 100% and aneurysmal dilation 30%.<br />
Conclusion: Patency of electrospun PDS 1-mm grafts is excellent. If the prosthesis was manufactured<br />
with PDS alone, aneurysm formation was seen in all cases. External wrapping or<br />
blending PDS with PLA seemed to prevent this complication at 3-weeks. However, at 6 and 12<br />
weeks aneurysmal dilation was found in 30%. Therefore, combinations or wrapping of the<br />
grafts with stronger polymers may be required. In conclusion, electrospun PDS-based polymers<br />
may be promising materials for vascular tissue engineering.<br />
17.13<br />
P.C. Nett 1 , D. Stroka 1 , D. Candinas 2<br />
1 Clinic of Visceral- and Transplant Surgery, University Hospital of Berne, 3010 Berne/CH,<br />
2 Visceral and Transplantation Surgery, University Berne; Inselspital, 3010 Berne/CH<br />
Hypoxia driven endothelin receptor ETRA and ETRB expression is dependent on cellular differentation<br />
in pancreatic carcinoma<br />
Objective: Endothelin (ET), a potent endogenous vasoconstrictor and mitogen, is supposed to<br />
contribute to proliferation of tumour cells and to tumour angiogenesis. The pathway by which<br />
tumour cells produce increased levels of ETs has not been completely elucidated, but appears<br />
to involve transcriptional regulation of its two specific cell surface receptors (ETR), ETRA<br />
and ETRB, and hypoxia that induces angiogenesis. To determine whether gene expression of<br />
ET and its receptors is regulated by hypoxia in pancreatic adenocarcinoma, we studied their<br />
transcriptional activity in a model of human pancreatic adenocarcinoma un<strong>der</strong> normoxic and<br />
hypoxic conditions.<br />
Methods: Two human pancreatic adenocarcinoma cell lines PANC-1 (poorly differentiated)<br />
and CAPAN-1 (mo<strong>der</strong>ately differentiated) were cultured un<strong>der</strong> hypoxic (1.5% oxygen) or normoxic<br />
(21% oxygen) conditions for 48 hours. Total RNA was isolated and and cDNA was synthesized.<br />
mRNA expression of human ET-1, ET-2, ET-3, ETRA and ETRB as well as endothelin<br />
converting enzyme (ECE)-1, ECE-2, were analyzed by semi-quantitative PCR.<br />
Results: There was constitutive mRNA expression of all the genes tested in both PANC-1 and<br />
CA-PAN-1 cells. The transcriptional activity of ET-3 was greater un<strong>der</strong> both normoxic and hypoxic<br />
conditions (p