Effect of Preoperative Chemotherapy on the Isolation Outcome of Primary Human Hepatocytes.

Primary human hepatocytes isolated from surgically resected liver tissue are an essential resource for pharmaceutical and toxicological studies. Patients undergoing partial liver resections have often received preoperative chemotherapy. The aim of our study was to investigate whether preoperative chemotherapy has effects on the outcome of cell isolation or the metabolic function of cultured hepatocytes. Liver specimens from 48 patients were used for hepatocyte isolation. Out of these, 21 patients had prior chemotherapy, with fluoropyrimidine-based regimen in 14 patients. Viability and cell yield as parameter for the outcome of isolation, as well as transaminase levels, urea or albumin secretion to the culture medium were not different between hepatocytes from pretreated and untreated donor. Furthermore, the transcription levels of cytochrome P450 (CYP) 1A2, CYP 2B6, and CYP 3A4 of cultured hepatocytes were not affected by prior chemotherapy of the tissue donors. In conclusion, hepatocytes from tissue donors that underwent fluoropyrimidine-based chemotherapy regimens before isolation seem to perform as well as hepatocytes without preoperative chemotherapy exposure. Our results suggest that hepatocytes from patients who received combination chemotherapy before liver resection are an uncompromised resource for pharmacological and toxicological studies. Impact statement Isolated primary human hepatocytes are an essential resource for pharmacological and toxicological studies. Our results present further evidence that isolated hepatocytes from patients who received combination chemotherapy before liver resection are an uncompromised resource for pharmacological and toxicological studies-especially when fluoropyrimidine-based regimens are used.

Global incidence and mortality of neonatal sepsis: a systematic review and meta-analysis.

BACKGROUND: Neonates are at major risk of sepsis, but data on neonatal sepsis incidence are scarce. We aimed to assess the incidence and mortality of neonatal sepsis worldwide. METHODS: We performed a systematic review and meta-analysis. 13 databases were searched for the period January 1979-May 2019, updating the search of a previous systematic review and extending it in order to increase data inputs from low-income and middle-income countries (LMICs). We included studies on the population-level neonatal sepsis incidence that used a clinical sepsis definition, such as the 2005 consensus definition, or relevant ICD codes. We performed a random-effects meta-analysis on neonatal sepsis incidence and mortality, stratified according to sepsis onset, birth weight, prematurity, study setting, WHO region and World Bank income level. RESULTS: The search yielded 4737 publications, of which 26 were included. They accounted for 2 797 879 live births and 29 608 sepsis cases in 14 countries, most of which were middle-income countries. Random-effects estimator for neonatal sepsis incidence in the overall time frame was 2824 (95% CI 1892 to 4194) cases per 100 000 live births, of which an estimated 17.6% 9 (95% CI 10.3% to 28.6%) died. In the last decade (2009-2018), the incidence was 3930 (95% CI 1937 to 7812) per 100 000 live births based on four studies from LMICs. In the overall time frame, estimated incidence and mortality was higher in early-onset than late-onset neonatal sepsis cases. There was substantial between-study heterogeneity in all analyses. Studies were at moderate to high risk of bias. CONCLUSION: Neonatal sepsis is common and often fatal. Its incidence remains unknown in most countries and existing studies show marked heterogeneity, indicating the need to increase the number of epidemiological studies, harmonise neonatal sepsis definitions and improve the quality of research in this field. This can help to design and implement targeted interventions, which are urgently needed to reduce the high incidence of neonatal sepsis worldwide.

Development of a Rat Liver Machine Perfusion System for Normothermic and Subnormothermic Conditions.

Ex vivo liver machine perfusion (MP) is a promising alternative for preservation of liver grafts from extended criteria donors. Small animal models can be used to evaluate different perfusion conditions. We here describe the development of a miniaturized ex vivo MP system for rat liver grafts, evaluating cell-free and erythrocyte-based perfusion solutions, subnormothermic and normothermic temperatures, and dialysis. A perfusion chamber was designed after a suitable liver position was identified. Normothermic ex vivo liver perfusion (NEVLP) required supplementation of erythrocytes to reduce cell damage. Perfusion with erythrocytes led to rising potassium levels after 12 h (NEVLP, 16.2 mM, interquartile range [IQR]: 5.7 and subnormothermic ex vivo liver perfusion [SNEVLP], 12.8 mM, IQR: 3.5), which were normalized by dialysis using a laboratory dialysis membrane (NEVLP, 6.2 mM, IQR: 0.5 and SNEVLP, 5.3 mM, IQR: 0.1; p = 0.004). Livers treated with NEVLP conditions showed higher bile production (18.52 mg/h/g, IQR: 8.2) compared to livers perfused under SNEVLP conditions (0.4 mg/h/g, IQR: 1.2, p = 0.01). Reducing the perfusion volume from 100 to 50 mL allowed for higher erythrocyte concentrations, leading to significantly lower transaminases (15.75 U/L/mL, IQR: 2.29 vs. 5.97 U/L/mL, IQR: 18.07, p = 0.002). In conclusion, a well-designed perfusion system, appropriate oxygen carriers, dialysis, and miniaturization of the perfusion volume are critical features for successful miniaturized ex vivo liver MP. Impact Statement Ex vivo liver machine perfusion (MP) is an emerging preservation alternative to static cold storage. Even though clinical studies have shown benefits for extended criteria donor grafts, standardized systems for perfusion of rat liver grafts are not available, which are inevitable for large-scaled studies on liver reconditioning by ex vivo MP. We here comprehensively describe the development of an ex vivo rat liver perfusion system that can be used as modular setting in various approaches of liver MP. We describe pitfalls and techniques that might be of interest when establishing such perfusion systems for basic and translational research.

Improvement of Normothermic Ex Vivo Machine Perfusion of Rat Liver Grafts by Dialysis and Kupffer Cell Inhibition With Glycine.

Normothermic ex vivo liver machine perfusion might be a superior preservation strategy for liver grafts from extended criteria donors. However, standardized small animal models are not available for basic research on machine perfusion of liver grafts. A laboratory-scaled perfusion system was developed consisting of a custom-made perfusion chamber, a pressure-controlled roller pump, and an oxygenator. Male Wistar rat livers were perfused via the portal vein for 6 hours using oxygenated culture medium supplemented with rat erythrocytes. A separate circuit was connected via a dialysis membrane to the main circuit for plasma volume expansion. Glycine was added to the flush solution, the perfusate, and the perfusion circuit. Portal pressure and transaminase release were stable over the perfusion period. Dialysis significantly decreased the potassium concentration of the perfusate and led to significantly higher bile and total urea production. Hematoxylin-eosin staining and immunostaining for single-stranded DNA and activated caspase 3 showed less sinusoidal dilatation and tissue damage in livers treated with dialysis and glycine. Although Kupffer cells were preserved, tumor necrosis factor α messenger RNA levels were significantly decreased by both treatments. For proof of concept, the optimized perfusion protocol was tested with donation after circulatory death (DCD) grafts, resulting in significantly lower transaminase release into the perfusate and preserved liver architecture compared with baseline perfusion. In conclusion, our laboratory-scaled normothermic portovenous ex vivo liver perfusion system enables rat liver preservation for 6 hours. Both dialysis and glycine treatment were shown to be synergistic for preservation of the integrity of normal and DCD liver grafts.

The Predictive Value of the Maximal Liver Function Capacity Test for the Isolation of Primary Human Hepatocytes.

The need for primary human hepatocytes is constantly growing for basic research, as well as for therapeutic applications. However, the isolation outcome strongly depends on the quality of liver tissue, and we are still lacking a preoperative test that allows the prediction of the hepatocyte isolation outcome. In this study, we evaluated the "maximal liver function capacity test" (LiMAx) as predictive test for the quantitative and qualitative outcome of hepatocyte isolation. This test is already used in clinical routine to measure preoperative and to predict postoperative liver function. The patient's preoperative mean LiMAx was obtained from the patient records, and preoperative computed tomography and magnetic resonance images were used to calculate the whole liver volume to adjust the mean LiMAx. The outcome parameters of the hepatocyte isolation procedures were analyzed in correlation with the adjusted mean LiMAx. Primary human hepatocytes were isolated from partial hepatectomies (n = 64). From these 64 hepatectomies we included 48 to our study and correlated their isolation outcome parameters with volume corrected LiMAx values. From a total of 11 hepatocyte isolation procedures, metabolic parameters (albumin, urea, and aspartate aminotransferase or AST) were assessed during the hepatocyte cultivation period of 5 days. The volume adjusted mean LiMAx showed a significant positive correlation with the total cell yield (p = 0.049; r = 0.242; n = 48). The correlations of volume adjusted LiMAx values with viable cell yield and cell viability did not reach statistical significance. To create a more homogenous study group regarding tumor entities, subgroup analyses were performed. A subgroup analysis of isolations from patients with colorectal metastasis revealed a significant correlation between volume adjusted mean LiMAx and total cell yield (p = 0.012; r = 0.488; n = 21) and viable cell yield (p = 0.034; r = 0.405; n = 21), whereas a subgroup analysis of isolations of patients with carcinoma of the biliary tree showed significant correlations of volume adjusted mean LiMAx with cell viability (r = 0.387; p = 0.046; n = 20) and lacked significant correlations with total cell yield (r = -0.060; p = 0.401; n = 20) and viable cell yield (r = 0.012; p = 0.480; n = 20). The volume-adjusted mean LiMAx did not show a significant correlation with any of the metabolic parameters. In conclusion, the LiMAx test might be a useful tool to predict the quantitative outcome of hepatocyte isolation, as long as underlying liver disease is taken into consideration.

Mixed Reality in Visceral Surgery: Development of a Suitable Workflow and Evaluation of Intraoperative Use-cases.

OBJECTIVE: The paper evaluates the application of a mixed reality (MR) headmounted display (HMD) for the visualization of anatomical structures in complex visceral-surgical interventions. A workflow was developed and technical feasibility was evaluated. SUMMARY OF BACKGROUND DATA: Medical images are still not seamlessly integrated into surgical interventions and, thus, remain separated from the surgical procedure.Surgeons need to cognitively relate 2-dimensional sectional images to the 3-dimensional (3D) during the actual intervention. MR applications simulate 3D images and reduce the offset between working space and visualization allowing for improved spatial-visual approximation of patient and image. METHODS: The surgeon's field of vision was superimposed with a 3D-model of the patient's relevant liver structures displayed on a MR-HMD. This set-up was evaluated during open hepatic surgery. RESULTS: A suitable workflow for segmenting image masks and texture mapping of tumors, hepatic artery, portal vein, and the hepatic veins was developed. The 3D model was positioned above the surgical site. Anatomical reassurance was possible simply by looking up. Positioning in the room was stable without drift and minimal jittering. Users reported satisfactory comfort wearing the device without significant impairment of movement. CONCLUSION: MR technology has a high potential to improve the surgeon's action and perception in open visceral surgery by displaying 3D anatomical models close to the surgical site. Superimposing anatomical structures directly onto the organs within the surgical site remains challenging, as the abdominal organs undergo major deformations due to manipulation, respiratory motion, and the interaction with the surgical instruments during the intervention. A further application scenario would be intraoperative ultrasound examination displaying the image directly next to the transducer. Displays and sensor-technologies as well as biomechanical modeling and object-recognition algorithms will facilitate the application of MR-HMD in surgery in the near future.

Hepatocyte Isolation After Laparoscopic Liver Resection.

Liver tissue obtained from partial hepatectomy is a common source for isolation of primary human hepatocytes. Until now, liver resections were most commonly performed by conventional open surgery. Although the laparoscopic approach is currently emerging in liver surgery, data on the outcome of hepatocyte isolation from laparoscopically resected liver tissue are not available. A total of 22 hepatocyte isolations were performed using the two-step collagenase perfusion technique from October 2015 to March 2016. Liver tissue was obtained from n = 15 open liver resections (OLRs) and n = 7 laparoscopic liver resections (LLRs). Isolation parameters (cell yield, viability, and Percoll survival) were assessed and hepatocyte function (plating efficiency, urea, albumin, and aspartate aminotransferase) was measured over a culture period of 6 days (OLR: n = 13; LLR: n = 3). Total cell yield (OLR: 36.81 ± 6.77 × 10(6) cells/g vs. LLR 16.84 ± 10.66 × 10(6) cells/g, p = 0.0318) as well as viable yield (OLR 31.70 ± 6.05 × 10(6) cells/g vs. LLR 14.70 ± 9.89 × 10(6) cells/g, p = 0.0260) was significantly higher in the OLR group. Subgroup analysis revealed that the worse outcome of isolation of laparoscopically resected liver tissue was associated with right-lateral LLRs, whereas hepatocyte isolation from left-lateral LLRs was as effective as from open surgery. Hepatocyte function did not differ between hepatocytes from openly resected versus left-lateral laparoscopically resected liver tissue. We here present the first data on hepatocyte isolation from laparoscopic liver surgery. Although the overall outcome is worse compared with open surgery, our data suggest that liver tissue from laparoscopic resection of the left lobe is an excellent source for primary human hepatocytes.