Medizinische Fakultät - Digitale Hochschulschriften der LMU - Teil 13/19 Archiv

OBJECTIVE: Therapy for muscular ventricular septal defects beyond the moderator band, especially in neonates and infants, has always been challenging for both surgeons and cardiologists. Recently, we established a patch closure hybrid therapy for muscular ventricular septal defects. In this study, we evaluated it in a long-term porcine model. METHODS: Thirteen minipigs underwent anterolateral thoracotomy to expose the left ventricle. Muscular ventricular septal defects were created under 2- and 3-dimensional echocardiographic guidance with a 7.5-mm sharp punch instrument. Closure of the defects was undertaken with our new patch system in hybrid technique. Animals were observed for 3 months. Echocardiographic evaluation and pathologic examination, including immunohistochemical staining, were undertaken. RESULTS: Defects were successfully created in 12 pigs and closed in 10 pigs. Seven survived for 3 months. Residual shunting was noticed in 1 animal. Neither left ventricular dysfunction nor relevant damage to the valves could be detected. Pathologic examination showed complete endothelialization of the patch and the nitinol anchors without protruding parts of the system. Cellular organization was proceeding. Immunohistochemical staining demonstrated endothelial cells on the surface of the patch and fibromuscular cells around the patch. CONCLUSION: Our hybrid therapy was efficacious in closing muscular ventricular septal defects without impairment of cardiac function. The patch system and nitinol anchors demonstrated good integration into the septum. Further development of the system for human application is already being undertaken

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to exert an unexpected pro-survival, pro-proliferative and pro-invasive effect on a subset of human cancer cell lines. Recent clinical studies report that increased expression of endogenous TRAIL is associated with decreased disease-specific survival in renal cell carcinoma and cholangiocarcinoma which are resistant to TRAIL induced apoptosis. The present work investigated the role of endogenous TRAIL as an intrinsic growth factor in apoptosis-resistant human cancer cells. Several cell lines derived from solid human tumors were studied, among them the neuroblastoma cell line KELLY, a cancer cell line resistant to TRAIL-induced apoptosis. First, to investigate whether TRAIL-knockdown could inhibit cell growth, the use of small interfering RNAs (siRNA) for endogenous TRAIL was established and a successful knockdown was verified on both mRNA and protein level. Second, the functional impact of the knockdown of endogenous TRAIL was investigated by measuring cell growth and cell death after transfection: Interestingly, the human neuroblastoma cell line KELLY unexpectedly showed markedly reduced cell growth upon knockdown of endogenous TRAIL. Furthermore, knockdown of TRAIL induced cell death in KELLY cells, which was dependent on caspase-signaling and rescued by the addition of soluble TRAIL. Thus, endogenous TRAIL functions as an intrinsic survival and growth factor in the neuroblastoma cell line KELLY. The present work provided first evidence that the expression of endogenous TRAIL can be specifically downregulated through siRNA knockdown to inhibit survival and growth of cancer cells in-vitro, which are resistant to TRAIL induced apoptosis. The present data strongly supports the potential of endogenous TRAIL to function as a novel therapeutic target in cancer therapy. In the light of the emerging clinical use of siRNAs for cancer therapy, targeting TRAIL by RNA interference may provide a valuable treatment approach for patients with cancers resistant to TRAIL induced apoptosis and high expression levels of endogenous TRAIL.

Aufgrund der steigenden Lebenserwartung von Patienten mit cystischer Fibrose (CF) nimmt die Prävalenz einer gestörte Glukosetoleranz (IGT) und eines CF-assoziierten Diabetes mellitus (CFRD)kontinuierlich zu. In der vorliegenden Arbeit wurde die Prävalenz von Glukosestoffwechselstörungen und deren Einfluss auf den klinischen Status in einer nicht vorselektionierten Gruppe von erwachsenen CF Patienten (n=34) im Vergleich zu neu-diagnostizierten Patienten mit Typ 2 Diabetes (n=9) und gesunden Kontrollpersonen (n=10) mittels oGTT untersucht. Desweiteren wurde durch Messung von Insulin, intaktem Proinsulin, intaktem GLP1 und der Bestimmung verschiedener Indices für die ß-Zellfunktion und die Insulinresistenz mögliche pathophysiologische Mechanismen in verschiedenen Stadien der Glukosetoleranzstörung untersucht. Bei den CF Patienten (Alter 30,2±8 Jahre, BMI 20,9 ±2,5 kg/m2) zeigten 50% der Patienten eine gestörten Glukosetoleranz (12% IFG, 23% IGT, 15% neu diagnostizierter CFRD). Im oGTT war der maximale Insulinpeak und die totale Insulinsekretionskapazität nicht unterschiedlich in den CF-Gruppen (AUCinsulin0-120min NGT: 3296±547 μU/ml, IFG: 3694±809 μU/ml, IGT: 3337±535 μU/ml, CFRD: 2387±318 μU/ml) und den Kontrollpersonen(3704±335 μU/ml). Bei CF-Patienten war ähnlich wie bei DM2 Patienten eine verminderte erste Phase der Insulinsekretion und eine zeitliche Verschiebung des Insulinpeaks nachweisbar, die mit der Verschlechterung der Glukosetoleranz assoziiert war (Stumvoll-FPIR NGT:450±291; IFG:252±203; IGT:309±254; CFRD:18±41; Kontrollen:950±388). Die Insulinsekretion korrelierte invers mit dem Glukoseprofil, so dass bei IFG und IGT hohe postprandiale Glukosespiegel innerhalb der ersten 60 Minuten und ein Blutzuckerabfall nach 120-180 min zu beobachten waren. Die Proinsulinspiegel und die GLP-1 Spiegel im oGTT waren nicht unterschiedlich im Vergleich zu den gesunden Kontrollen. Im Gegensatz zu den DM2 Patienten konnte bei CF Patienten keine deutliche Insulinresistenz festgestellt werden. Bei den CF Patienten war eine Verschlechterung der Lungenfunktion und des Ernährungszustandes mit zunehmender Glukoseintoleranz zu sehen. Hohe maximale Glukosespiegel(rs=-0,50, p=0,002), der Insulinogenic Index (rs = 0,36, p