Untersuchung chirurgischer Techniken zur Behandlung fortgeschrittener Lebererkrankungen und assoziierter Risikofaktoren

In den folgenden Publikationen wurden folgende Fragestellungen systematisch untersucht: 1. Der Stellenwert der präoperativen Bildgebung für die chirurgische Strategie bei der portosystemischen Shunt-Chirurgie. 2. Die Machbarkeit der Lebertransplantation ohne Kältekonservierung 3. Die Assoziation zwischen der Rekurrenz des hepatozellulären Karzinoms nach Lebertransplantation mit Episoden akuter Abstoßung 4. Der Einfluss der Teil-Leber-Lebendspende auf die Lebensqualität des Spenders und Untersuchung postoperativer Ergebnisse 5. Der Stellenwert eines biologischen Netzes beim Bauchwandverschlusses in mehreren Etappen nach pädiatrischer Lebertransplantation bei Kleinkinder

Outcome after pediatric liver transplantation for staged abdominal wall closure with use of biological mesh—Study with long‐term follow‐up

Abdominal wall closure after pediatric liver transplantation (pLT) in infants may be hampered by graft-to-recipient size discrepancy. Herein, we describe the use of a porcine dermal collagen acellular graft (PDCG) as a biological mesh (BM) for abdominal wall closure in pLT recipients. Patients <2 years of age, who underwent pLT from 2011 to 2014, were analyzed, divided into definite abdominal wall closure with and without implantation of a BM. Primary end-point was the occurrence of postoperative abdominal wall infection. Secondary end-points included 1- and 5-year patient and graft survival and the development of abdominal wall hernia. In five out of 21 pLT recipients (23.8%), direct abdominal wall closure was achieved, whereas 16 recipients (76.2%) received a BM. BM removal was necessary in one patient (6.3%) due to abdominal wall infection, whereas no abdominal wall infection occurred in the no-BM group. No significant differences between the two groups were observed for 1- and 5-year patient and graft survival. Two late abdominal wall hernias were observed in the BM group vs none in the no-BM group. Definite abdominal wall closure with a BM after pLT is feasible and safe when direct closure cannot be achieved with comparable postoperative patient and graft survival rates

Treatment of Anti-HLA Donor-Specific Antibodies Results in Increased Infectious Complications and Impairs Survival after Liver Transplantation

Donor-specific anti-human leukocyte antigen antibodies (DSA) are controversially discussed in the context of liver transplantation (LT). We investigated the relationship between the presence of DSA and the outcome after LT. All the LTs performed at our center between 1 January 2008 and 31 December 2015 were examined. Recipients < 18 years, living donor-, combined, high-urgency-, and re-transplantations were excluded. Out of 510 LTs, 113 DSA-positive cases were propensity score-matched with DSA-negative cases based on the components of the Balance of Risk score. One-, three-, and five-year survival after LT were 74.3% in DSA-positive vs. 84.8% (p = 0.053) in DSA-negative recipients, 71.8% vs. 71.5% (p = 0.821), and 69.3% vs. 64.9% (p = 0.818), respectively. Rejection therapy was more often applied to DSA-positive recipients (n = 77 (68.1%) vs. 37 (32.7%) in the control group, p < 0.001). At one year after LT, 9.7% of DSA-positive patients died due to sepsis compared to 1.8% in the DSA-negative group (p = 0.046). The remaining causes of death were comparable in both groups (cardiovascular 6.2% vs. 8.0%; p = 0.692; hepatic 3.5% vs. 2.7%, p = 0.788; malignancy 3.5% vs. 2.7%, p = 0.788). DSA seem to have an indirect effect on the outcome of adult LTs, impacting decision-making in post-transplant immunosuppression and rejection therapies and ultimately increasing mortality due to infectious complications

an intravital microscopic study on mice

Die Wandschubspannung ist ein zentraler Faktor der mikrovaskulären Hämodynamik. Ihre tangentiale Wirkung auf die Endothelzellen gewährleistet und etabliert die Aufrechterhaltung eines physiologischen Gleichgewichtes der Perfusion in vielen Geweben, so auch im Skelettmuskel. Wie die mikrovaskuläre Hämodynamik in dem jeweiligen Gewebe sich in einer Feedback-Reaktion adaptiert, ist jedoch weitgehend unbekannt. Allerdings scheint das Signalmolekül (NO), hergestellt durch NO-Synthasen (NOS) dabei eine wichtige Rolle einzunehmen. Im Skelettmuskel wird NO sowohl durch die im Endothelium verankerte eNOS als auch durch die sarkolemmal lokalisierte nNOS bereitgestellt. Das Ziel in der vorliegenden Arbeit war es in vivo den Einfluss der eNOS und nNOS auf die Etablierung der Wandschubspannung in Kapillaren zu analysieren. Die Umsetzung dieser Fragestellung konnte nach Ausarbeitung und Etablierung eines intravitalmikroskopischen Verfahrens erfolgen. Auf diese Art konnte das mikrovaskuläre Kapillarsystem im Musculus extensor digitorum longus (EDL) der Maus durch kontinuierliches Videomonitoring dargestellt und offline analysiert werden. Im Rahmen der Auswertung erfolgte durch Bestimmung der Geschwindigkeit der Erythrozytenströmung und des Kapillardurchmessers eine Berechnung der apparenten Wandschubspannung in den Kapillaren. Diese Untersuchungen wurden an drei Mausstämmen (C57/B16-, nNOS- und eNOS-Knockout-Mäuse) sowohl im unbehandelten (basal) als auch nach Behandlung mit Prazosin (über 36 Stunden als Zusatz im Trinkwasser) durchgeführt. Alle Versuchstiere der Kontrollgruppe ohne Prazosinbehandlung wiesen während der intravitalmikroskopischen Untersuchung einen nahezu konstanten mittleren arteriellen Blutdruck von 90 – 110 mmHg auf. Der Vergleich zu den Versuchsgruppen nach Prazosinbehandlung präsentierte dagegen eine deutliche Erniedrigung des mittleren arteriellen Blutdruckes auf 80 – 100 mmHg. In beiden Gruppen mit und ohne Prazosinbehandlung lag der durchschnittliche Kapillardurchmesser zwischen 6,0 +/- 0,5 μm. Es zeigen sich keine signifikanten Unterschiede im Vergleich der einzelnen Gruppen. Auffallend war die Veränderung der Erythrozytenflussgeschwindigkeiten in den einzelnen Versuchsgruppen. So hatten die nNOS-defizienten Mäuse mit 90 μm/sec im Vergleich zu den eNOS-defizienten Mäusen mit 80 μm/sec und den C57/Bl6-Mäuse mit 70 μm/sec die höchsten Werte. Eine signifikante Änderung im Sinne einer Geschwindigkeitssteigerung um das 2- bis 3-fache in den Kapillaren war nach der Behandlung mit Prazosin nachweisbar. Es ließen sich Messwerte zwischen 200 - 300 μm/sec bei den eNOS- und nNOS-defizienten sowie den C57/B16-Mäusen ableiten. Die hieraus berechnete Wandschubspannung zeigte analog in allen drei Mausgruppen nach Prazosinbehandlung eine signifikante Erhöhung der Wandschubspannung. Die Werte für die Wandschubspannung lagen ohne Behandlung zwischen 2 – 4 dyne/cm². Nach Prazosinbehandlung (high flow) steigerte sich die Wandschubspannung auf Werte zwischen 11 – 14 dyne/cm². Weder unter Basalbedingungen noch unter high flow Bedingungen nach Prazosinbehandlung führte die genetische Ablation von nNOS und eNOS zu einer veränderten Wandschubspannung. Diese Daten lassen vermuten, dass NO nicht bei der Erhöhung der Wandschubspannung nach arterieller Vasodilatation beteiligt ist.The wall shear stress is a central factor in microvascular hemodynamics. Its tangential effect on the endothelial cells allows perfusion in many tissues, including the skeletal muscles, to be kept physiologically balanced. The way in which the microvascular hemodynamics is adapted to the respective tissues in a feedback reaction is largely unknown. However, the signal molecule (NO), made by NO synthases (NOS) appears to play an important role. NO is present in the skeletal muscles both as eNOS embedded in the endothelium and as nNOS found in the sarcolemma. The aim of this study was to analyse the effect of eNOS and nNOS on the establishment of the wall shear stress in capillaries in vivo. The research question was investigated by developing and using an intravital microscopic process. In this way, the microvascular capillary system in the extensor digitorum longus (EDL) muscle of the mouse could be shown with continuous video monitoring and analysed offline. In terms of evaluation, a calculation of the apparent wall shear stress in the capillaries was made by determining the speed of the erythrocyte flow and the capillary diameter. These investigations were carried out on three strains of mouse (C57/B16, nNOS and eNOS knockout mice), both untreated (control) and after treatment with Prazosin (added to the drinking water over a period of 36 hours). All test animals in the control group not being treated with Prazosin showed a virtually constant central arterial blood pressure of 90 – 110 mmHg during the intravital microscopic tests. In comparison, the test group following treatment with Prazosin showed a significant decrease in the central arterial blood pressure to 80 – 100 mmHg. In both groups with and without treatment with Prazosin, the average capillary diameter was 6.0 +/- 0.5 µm. There were no significant differences within the individual groups. The change in the erythrocyte speeds within the individual test groups was notable. The nNOS-48 deficient mice showed highest speeds of 90 µm/sec as compared with the eNOS-deficient mice with speeds of 80 µm/sec and the C57/B16 mice with speeds of 70 µm/sec. A significant increase in speed of 2 to 3 times could be seen in the capillaries after treatment with Prazosin. Measurement values between 200 - 300 µm/sec could be identified for the eNOS, nNOS-deficient and the C57/B16 mice. The wall shear stress calculated from this showed a significant increase in wall shear stress after treatment with Prazosin for all three groups of mice. The values for the wall shear stress were between 2 – 4 dyne/cm2 for mice which had not been treated with Prazosin. After treatment with Prazosin (high flow) the wall shear stress increased to between 11 – 14 dyne/cm2. Genetic ablation of nNOS and eNOS did not lead to a change in the wall shear stress in either the control group or under high flow conditions after treatment with Prazosin. The assumption can therefore be made that NO is not involved in the increase in wall shear stress following arterial vasodilation

Long-Term Outcome after Liver Transplantation for Progressive Familial Intrahepatic Cholestasis

Background and Objectives: Progressive familial intrahepatic cholestasis (PFIC) is a rare autosomal recessive inherited disease divided into five types (PFIC 1-5). Characteristic for all types is early disease onset, which may result clinically in portal hypertension, fibrosis, cirrhosis, hepatocellular carcinoma (HCC), and extrahepatic manifestations. Liver transplantation (LT) is the only successful treatment approach. Our aim is to present the good long-term outcomes after liver transplantation for PFIC1, focusing on liver function as well as the occurrence of extrahepatic manifestation after liver transplantation. Materials and Methods: A total of seven pediatric patients with PFIC1 underwent liver transplantation between January 1999 and September 2019 at the Department of Surgery, Charite Campus Virchow Klinikum and Charite Campus Mitte of Charite-Universitatsmedizin Berlin. Long-term follow-up data were collected on all patients, specifically considering liver function and extrahepatic manifestations. Results: Seven (3.2%) recipients were found from a cohort of 219 pediatric patients. Two of the seven patients had multilocular HCC in cirrhosis. Disease recurrence or graft loss did not occur in any patient. Two patients (male, siblings) had persistently elevated liver parameters but showed excellent liver function. Patient and graft survival during long-term follow-up was 100%, and no severe extrahepatic manifestations requiring hospitalization or surgery occurred. We noted a low complication rate during long-term follow-up and excellent patient outcome. Conclusions: PFIC1 long-term follow-up after LT shows promising results for this rare disease. In particular, the clinical relevance of extrahepatic manifestations seems acceptable, and graft function seems to be barely affected. Further multicenter studies are needed to analyze the clinically inhomogeneous presentation and to better understand the courses after LT

Portosystemic shunt surgery in the era of TIPS: imaging-based planning of the surgical approach

Purpose: With the spread of transjugular intrahepatic portosystemic shunts (TIPS), portosystemic shunt surgery (PSSS) has decreased and leaves more complex patients with great demands for accurate preoperative planning. The aim was to evaluate the role of imaging for predicting the most suitable PSSS approach. Material and methods: Forty-four patients who underwent PSSS (2002 to 2013) were examined by contrast-enhanced CT (n = 33) and/or MRI (n = 15) prior to surgery. Imaging was analyzed independently by two observers (O1 and O2) with different levels of experience (O1 > O2). They recommended two shunting techniques (vessels and anastomotic variant) for each patient and ranked them according to their appropriateness and complexity. Findings were compared with the actually performed shunt procedure and its outcome. Results: The first two choices taken together covered the performed PSSS regarding vessels in 88%/100% (CT/MRI, O1) and 76%/73% (O2); and vessels + anastomosis in 79%/73% (O1) and 67%/60% (O2). The prediction of complex surgical procedures (resection of interposing structures, additional thrombectomy, use of a collateral vessel, and use of a graft interposition) was confirmed in 87%, resulting in 80% sensitivity and 96% specificity. Larger shunt vessel distances were associated with therapy failure (p = 0.030) and a vessel distance of ≥ 20 mm was identified as optimal cutoff, in which a graft interposition was used. There was no significant difference between MRI and CT in predicting the intraoperative decisions (p = 0.294 to 1.000). Conclusion: Preoperative imaging and an experienced radiologist can guide surgeons in PSSS. CT and MRI provide the information necessary to identify technically feasible variants and complicating factors

Initial Experience with the Safe Implementation of Transanal Total Mesorectal Excision (TaTME) as a Standardized Procedure for Low Rectal Cancer

Introduction: The laparoscopic approach for TME is proven to be non-inferior in oncological outcome compared to open surgery. Anatomical limitations in the male and obese pelvis with resulting pathological shortcomings and high conversion rates were stimuli for alternative approaches. The transanal approach for TME (TaTME) was introduced to overcome these limitations. The aim of this study was to evaluate the outcomes of TaTME for mid and low rectal cancer at our center. Methods: TaTME is a hybrid procedure of simultaneously laparoscopic and transanal mesorectal excision. A retrospective analysis of all consecutive TaTME procedures performed at our center for mid and low rectal cancer between December 2014 and January 2020 was conducted. Results: A total of 157 patients underwent TaTME, with 72.6% receiving neoadjuvant chemoradiation. Mean tumor height was 6.1 ± 2.3 cm from the anal verge, 72.6% of patients had undergone neoadjuvant chemoradiotherapy, and 34.2% of patients presented with a threatened CRM upon pretherapeutic MRI. Abdominal conversion rate was 5.7% with no conversion for the transanal dissection. Early anastomotic leakage occurred in 7.0% of the patients. Mesorectum specimen was complete in 87.3%, R1 resection rate was 4.5% (involved distal resection margin) and in 7.6%, the CRM was positive. The three-year local recurrence rate of 58 patients with a follow-up ≥ 36 months was 3.4%. Overall survival was 92.0% after 12 months, and 82.2% after 36 months. Conclusion: TaTME can be performed safely with acceptable long-term oncological outcome. Low rectal cancer can be well addressed by TaTME, which is an appropriate alternative with low conversion, local recurrence, adequate mesorectal quality and CRM positivity rates

Phenotype of capillaries in skeletal muscle of nNOS-knockout mice

Because neuronal nitric oxide synthase (nNOS) has a well-known impact on arteriolar blood flow in skeletal muscle, we compared the ultrastructure and the hemodynamics of/in the ensuing capillaries in the extensor digitorum longus (EDL) muscle of male nNOS-knockout (KO) mice and wild-type (WT) littermates. The capillary-to-fiber (C/F) ratio (-9.1%) was lower (P ≤ 0.05) in the nNOS-KO mice than in the WT mice, whereas the mean cross-sectional fiber area (-7.8%) and the capillary density (-3.1%) varied only nonsignificantly (P > 0.05). Morphometrical estimation of the area occupied by the capillaries as well as the volume and surface densities of the subcellular compartments differed nonsignificantly (P > 0.05) between the two strains. Intravital microscopy revealed neither the capillary diameter (+3% in nNOS-KO mice vs. WT mice) nor the mean velocity of red blood cells in EDL muscle (+25% in nNOS-KO mice vs. WT mice) to significantly vary (P > 0.05) between the two strains. The calculated shear stress in the capillaries was likewise nonsignificantly different (3.8 ± 2.2 dyn/cm² in nNOS-KO mice and 2.1 ± 2.2 dyn/cm² in WT mice; P > 0.05). The mRNA levels of vascular endothelial growth factor (VEGF)-A were lower in the EDL muscle of nNOS-KO mice than in the WT littermates (-37%; P ≤ 0.05), whereas mRNA levels of VEGF receptor-2 (VEGFR-2) (-11%), hypoxia inducible factor-1α (+9%), fibroblast growth factor-2 (-14%), and thrombospondin-1 (-10%) differed nonsignificantly (P > 0.05). Our findings support the contention that VEGF-A mRNA expression and C/F-ratio but not the ultrastructure or the hemodynamics of/in capillaries in skeletal muscle at basal conditions depend on the expression of nNOS