Due to a vulnerable blood supply of the bile ducts, biliary complications are a major source of morbidity after liver transplantation (LT). Manifestation is either seen at the anastomotic region or at multiple locations of the donor biliary system, termed as nonanastomotic biliary strictures. Major risk factors include old donor age, marginal grafts and prolonged ischemia time. Moreover, partial LT or living donor liver transplantation (LDLT) and donation after cardiac death (DCD) bear a markedly higher risk of biliary complications. Especially accumulation of several risk factors is critical and should be avoided. Prophylaxis is still a major issue; however no gold standard is established so far, since many risk factors cannot be influenced directly. The diagnostic workup is mostly started with noninvasive imaging studies namely MRI and MRCP, but direct cholangiography still remains the gold standard. Especially nonanastomotic strictures require a multidisciplinary treatment approach. The primary management of anastomotic strictures is mainly interventional. However, surgical revision is finally indicated in a significant number of cases. Using adequate treatment algorithms, a very high success rate can be achieved in anastomotic complications, but in nonanastomotic strictures a relevant number of graft failures are still inevitable.

Background Hemostasis is a central issue in laparoscopic surgery. Ultrasonic scissors and bipolar clamps are commonly used, with known advantages with each technique. Methods The prototype of new surgical scissors, delivering ultrasonically generated frictional heat energy and bipolar heat energy simultaneously (THUNDERBEAT^® [TB]), was compared to ultrasonic scissors (Harmonic ACE^® [HA]) and an advanced bipolar device (LigaSure^® [LS]) using a pig model. As safety parameters, temperature profiles after single activation and after a defined cut were determined. As efficacy parameters, seal failures and the maximum burst pressure (BP) were measured after in vivo sealing of vessels of various types and diameters (categories 2–4 and 5–7 mm). Moreover, the vertical width of the tissue seal was measured on serial histological slices of selected arteries. The cutting speed was measured during division of isolated arteries and during dissection of a defined length of compound tissue (10 cm of mesentery). Burst-pressure measurement and histological analysis were performed by investigators blinded to the used sealing device. Results Using the TB, the burst pressure in larger arteries was significantly higher (734 ± 64 mmHg) than that of the HA (453 ± 50 mmHg). No differences in the rate of seal failures were observed. The cutting speed of the TB was significantly higher than that of all other devices. Safety evaluation revealed temperatures below 100 °C in the bipolar device. The maximum temperature of the HA and the TB was significantly higher. No relevant differences were observed between the HA and the TB. Conclusions The ultrasonic and bipolar technique of the TB has the potential to surpass the dissection speed of ultrasonic devices with the sealing efficacy of bipolar clamps. However, heat production that is comparable to conventional ultrasonic scissors should be minded for clinical use.

Introduction: In recent years the development of secondary sclerosing cholangitis in critically ill patients (SSC-CIP) has increasingly been perceived as a separate disease entity. About possible trigger mechanisms of SSC-CIP has been speculated, systematic investigations on this issue are still lacking. The purpose of this study was to evaluate the prevalence and influence of promoting factors. Methods: Temporality, consistency and biological plausibility are essential prerequisites for causality. In this study, we investigated the temporality and consistency of possible triggers of SSC-CIP in a large case series. Biological plausibility of the individual triggers is discussed in a scientific context. SSC-CIP cases were recruited retrospectively from 2633 patients who underwent or were scheduled for liver transplantation at the University Hospital Charité, Berlin. All patients who developed secondary sclerosing cholangitis in association with intensive care treatment were included. Possible trigger factors during the course of the initial intensive care treatment were recorded. Results: Sixteen patients (68% males, mean age 45.87 ± 14.64 years) with a confirmed diagnosis of SSC-CIP were identified. Of the 19 risk factors investigated, particularly severe hypotension with a prolonged decrease in mean arterial blood pressure (MAP) to <65 mmHg and systemic inflammatory response syndrome (SIRS) were established as possible triggers of SSC-CIP. The occurrence of severe hypotension appears to be the first and most significant step in the pathogenesis. It seems that severe hypotension has a critical effect on the blood supply of bile ducts when it occurs together with additional microcirculatory disturbances. Conclusions: In critically ill patients with newly acquired cholestasis the differential diagnosis of SSC-CIP should be considered when they have had an episode of haemodynamic instability with a prolonged decrease in MAP, initial need for large amounts of blood transfusions or colloids, and early development of a SIRS.

Global deregulation of DNA methylation is one of the crucial causes of hepato cellular carcinoma (HCC). It has been reported that the anti-cancer drug 5-azacytidine (5-AZA) mediates the activation of tumor suppressor genes through passive demethylation by inhibiting DNMT1. Recent evidence suggests that active demethylation which is mediated by ten-eleven translocation (TET) proteins may also be an important step to control global methylation. However, there exists a controversial discussion in which TET proteins are involved in the demethylation process in HCC. Therefore, we firstly wanted to identify which of the TETs are involved in demethylation and later to study whether or not 5-AZA could trigger the TET-dependent active demethylation process in HCC. HCC cell lines (Huh-7, HLE, HLF), primary human hepatocytes (hHeps), and tissues from both healthy (55 patients) and HCC patients (55 patients) were included in this study; mRNA levels of isocitrate dehydrogenase (IDH1, 2) and TETs (TET1–3) were studied via qPCR and confirmed by Western blot. The expression of 5hmC/5mC was determined by immunohistochemistry in human HCC tissues and the corresponding adjacent healthy liver. HCC cell lines were stimulated with 5-AZA (0–20 μM) and viability (Resazurin conversion), toxicity (LDH release), proliferation (PCNA), and 5hmC/5mC distribution were assessed. In addition, knockdown experiments on TET proteins in HCC cell lines using short interference RNAs (siRNAs), in the presence and absence of 5-AZA, were performed. Our data applying qPCR, immunofluorescence, and Western blotting clearly show that TET2 and TET3 but not TET1 were significantly decreased in HCC tissue and different HCC cell lines compared to non-tumor liver tissues and hHeps. In addition, we show here for the first time applying knockdown experiments that 5-AZA is able to trigger an active TET2-dependent demethylation process with concomitant significant changes in 5hmC/5mC in HCC cell lines and hHeps. Our data clearly show that the expression and activity of TET2 and TET3 proteins but not TET1 are impaired in hepatocellular carcinoma leading to the reduction of 5hmC in HCCs. Furthermore, this study identified a novel function of 5-azacytidine in promoting a TET-mediated generation of 5hmC suggesting that the availability of 5-AZA in cancer cells will have various effects on different epigenetic targets. These findings may open new therapeutic strategies for epigenetic drugs to treat HCC.