[Anastomotic techniques in minimally invasive hepatobiliopancreatic surgery]. / Anastomosentechniken in der minimal-invasiven hepatobiliopankreatischen Chirurgie.

The established anastomotic techniques conventionally used in open surgery are increasingly being implemented in a minimally invasive approach and further developed. The aim of all innovations is to carry out a safe anastomosis with a feasible minimally invasive technique; however, there is currently no broad consensus about the role of laparoscopic and robotic surgery in performing pancreatic anastomotic techniques. Pancreatic fistulas determine the morbidity following a minimally invasive resection. The simultaneous minimally invasive resection and reconstruction of pancreatic processes and vascular structures is currently exclusively performed in specialized centers.

Body composition, mitochondrial oxygen metabolism and metabolome of patients with obesity before and after bariatric surgery (COMMITMENT): protocol for a monocentric prospective cohort study.

INTRODUCTION: Obesity, defined as a body mass index ≥30 kg/m2, is one of the most prevalent health conditions worldwide. It is part of the metabolic syndrome, which encompasses arterial hypertension, dyslipoproteinaemia and diabetes. Obesity is viewed as a systemic disease with pathophysiological mechanisms on the molecular level. Dysfunction of the mitochondrion and systemic low-grade inflammation are among the proposed causes for the metabolic changes. In severe cases of obesity, laparoscopic sleeve gastrectomy, a bariatric operation, can achieve the desired weight loss and has been associated with clinical outcome improvement. Hitherto, the influence of patients' body composition on mitochondrial function and concomitant metabolic changes has not been fully understood. This study aims to quantify the patient's body composition before and after laparoscopic sleeve gastrectomy and to correlate these findings with changes in mitochondrial oxygen metabolism, metabolome and immune status. METHODS AND ANALYSIS: In this prospective monocentric cohort study, patients undergoing laparoscopic sleeve gastrectomy (n=30) at Jena University Hospital (Germany) will be assessed before surgery and at four time points during a 1-year follow-up. Body composition will be measured by bioimpedance analysis. Non-invasive assessment of mitochondrial oxygen metabolism using protoporphyrin IX-triplet state lifetime technique (PPIX-TSLT) and blood sampling for, among other, metabolomic and immunological analysis, will be performed. The primary outcome is the difference in relative fat mass between the preoperative time point and 6 months postoperatively. Further outcomes comprise longitudinal changes of PPIX-TSLT and metabolic and immunological variables. Outcomes will be assessed using paired t-tests, Wilcoxon signed-rank tests and regression analyses. ETHICS AND DISSEMINATION: The study was approved by the Ethics Committee of Friedrich Schiller University Jena (2018-1192-BO). Written informed consent will be obtained from all patients prior to enrolment in the study. The results will be published in peer-reviewed journals and presented at appropriate conferences. TRIAL REGISTRATION NUMBER: DRKS00015891.

Robotic hepatic surgery in malignancy: review of the current literature.

The use of minimally invasive liver surgery, such as laparoscopic and robotic surgery, is increasing worldwide. Robot-assisted laparoscopy is a new surgical technique that improves surgical handling. The advantage of this technique is improved dexterity, which leads to increased surgical precision and no tremor or fatigue. Comparable oncological results were documented for laparoscopic and open surgery. Currently, "conventional" laparoscopic liver surgery has limitations with respect to the treatment of lesions in the posterior-superior segments, and there are limited technical features for the reconstruction steps. These limitations might be overcome with the use of robotic surgery. The use of robotic surgery for hepatic procedures originated because of the technical potential to overcome several of the major technical limitations known from conventional laparoscopy and the possibility of performing more extended liver resections. Additionally, there is increasing evidence indicating that robotic hepatic surgery is feasible and safe in resections of the posterior segments. Studies showed that using the robotic technique is associated with a decreased or at least equal amount of intraoperative blood loss compared to that of the conventional laparoscopic or open technique. There is increasing evidence that robotic liver surgery might be as safe as conventional laparoscopic procedures in cancer cases in terms of resection margins, disease-free and overall survival. Furthermore, robotic surgery might be more favorable with respect to postoperative patient recovery. Despite promising results, still large, multicenter, randomized and prospective studies are needed to analyze the exact value of robotic liver surgery in patients with malignant liver tumors.

[Influence of Attachment Style on the Outcome of Bariatric Surgery - A Pilot Study]. / Die Bedeutung des Bindungsstils für den Erfolg bariatrischer Operationen ­ Eine Pilotstudie.

Background: Bariatric surgery can lower body weight and comorbidities. Different factors might influence the outcome of this treatment. This pilot study examines whether patients' attachment style can influence surgical outcome. Methods: The sample consisted of 32 patients (f=24; m=8; BMI preoperative=47,8 kg/m2±5,2; age=53±9,84) who underwent a laparoscopic sleeve gastrectomy. The following variables were assessed pre- and postoperatively via questionnaires: quality of life (BAROS), self esteem (SES), depression, anxiety, psychological distress (SCL-90R), feelings of hunger, cognitive control, irritated eating behaviour (FEV) and weight related variables (BMI, EWL%, EBL%, TBL). Attachment style was determined postoperatively using the BPQE. Results: None of the participating patients suffered from a binge eating disorder. There was no significant difference of the BMI at any time between the 12 securely attached (SA) patients and the 19 insecurely attachted (IA) patients. Compared to the SA patients IA patients preoperatively showed lower outcomes in variables concerning eating behaviour and mental health. Comparing the 2 groups postoperatively the IA patients achieved lower levels in variables concerning mental health than SA patients and did not reach the preoperative values of the SA patients. Both groups benefited from surgery related to weight loss, mental health and eating behaviour. There was no difference found in the development from pre- to postoperative between SA and IA patients. Discussion & Conclusion: Patients profit by a bariatric intervention independent of their attachment style. By evaluating the attachment style, it could be possible to individually optimize pre- and postoperative patients support in order to gain more effective surgery results. Follow up studies extended to multi-site assessment are required.

Application of Digital Image Analysis to Determine Pancreatic Islet Mass and Purity in Clinical Islet Isolation and Transplantation.

Pancreatic islet mass, represented by islet equivalent (IEQ), is the most important parameter in decision making for clinical islet transplantation. To obtain IEQ, the sample of islets is routinely counted under a microscope and discarded thereafter. Islet purity, another parameter in islet processing, is routinely assessed by estimation only. In this study, we validated our digital image analysis (DIA) system by using the software of Image Pro Plus and a custom-designed Excel template to assess islet mass and purity to better comply with current good manufacturing practice (cGMP) standards. Human islet samples (60 collected from a single isolation and 24 collected from 12 isolations) were captured as calibrated digital images for the permanent record. Seven trained technicians participated in determination of IEQ and purity by the manual counting method (manual image counting, Manual I) and DIA. IEQ count showed statistically significant correlations between the Manual I and DIA in all sample comparisons (r > 0.819 and p < 0.0001). A statistically significant difference in IEQ between Manual I and DIA was not found in all sample groups (p > 0.05). In terms of purity determination, statistically significant differences between assessment and DIA measurement were found in high-purity 100-µl samples (p < 0.005) and low-purity 100-µl samples (p < 0.001) of the single isolation. In addition, islet particle number (IPN) and the IEQ/IPN ratio did not differ statistically between Manual I and DIA. In conclusion, the DIA used in this study is a reliable technique to determine IEQ and purity. Islet sample preserved as a digital image and results produced by DIA can be permanently stored for verification, technical training, and information exchange among islet centers. Therefore, DIA complies better with cGMP requirements than the manual counting method. We propose DIA as a quality control tool to supplement the established standard manual method for islet counting and purity estimation.

Bariatric surgery to treat obesity.

Obesity has become a global health problem that contributes to numerous life-threatening and disabling diseases, such as type 2 diabetes mellitus and coronary artery disease. The long-term results of traditional weight loss therapies, including diet, exercise, and medications, are relatively poor. Bariatric surgery is the most effective treatment of morbidly obese patients to allow substantial, sustained weight loss and to improve or resolve obesity-associated comorbidities, thereby reducing mortality. According to US practice guidelines, patients qualify for bariatric surgery with a body mass index of 35 kg/m(2) and associated comorbidities, or a body mass index of 40 kg/m(2), after failure of conservative weight loss measures. Currently, the established procedures in the United States are the laparoscopic Roux-en-Y gastric bypass, adjustable gastric banding, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch. The surgeries vary substantially in their postoperative amount of weight loss, resolution of comorbidities, nutritional requirements, and nature and severity of complications. There is no perfect bariatric surgery, an informed risk and benefit assessment should be made by each patient. The procedures are safe, with a mortality rate of 0.3%. Sustained weight loss depends finally on patient re-education in terms of diet, need for regular exercise, and careful bariatric follow-up evaluation.

Protein polymer hydrogels: effects of endotoxin on biocompatibility.

Protein polymer-based hydrogels have shown potential for tissue engineering applications, but require biocompatibility testing for in vivo use. Enzymatically crosslinked protein polymer-based hydrogels were tested in vitro and in vivo to evaluate their biocompatibility. Endotoxins present in the hydrogel were removed by Trition X-114 phase separation. The reduction of endotoxins decreased TNF-α production by a macrophage cell line in vitro; however, significant inflammatory response was still present compared to collagen control gels. A branched PEG molecule and dexamethasone were added to the hydrogel to reduce the response. In vitro testing showed a decrease in the TNF-α levels with the addition of dexamethasone. In vivo implantations into the epididymal fat pad of C57/BL6 mice, however, indicated a decreased inflammatory mediated immune response with a hydrogel treated with both PEGylation and endotoxin reduction. This study demonstrates the importance of endotoxin testing and removal in determining the biocompatibility of biomaterials.

Protein polymer MRI contrast agents: Longitudinal analysis of biomaterials in vivo.

Despite recent advances in tissue engineering to regenerate biological function by combining cells with material supports, development is hindered by inadequate techniques for characterizing biomaterials in vivo. Magnetic resonance imaging is a tomographic technique with high temporal and spatial resolution and represents an excellent imaging modality for longitudinal noninvasive assessment of biomaterials in vivo. To distinguish biomaterials from surrounding tissues for magnetic resonance imaging, protein polymer contrast agents were developed and incorporated into hydrogels. In vitro and in vivo images of protein polymer hydrogels, with and without covalently incorporated protein polymer contrast agents, were acquired by magnetic resonance imaging. T(1) values of the labeled gels were consistently lower when protein polymer contrast agents were included. As a result, the protein polymer contrast agent hydrogels facilitated fate tracking, quantification of degradation, and detection of immune response in vivo. For the duration of the in vivo study, the protein polymer contrast agent-containing hydrogels could be distinguished from adjacent tissues and from the foreign body response surrounding the gels. The hydrogels containing protein polymer contrast agent have a contrast-to-noise ratio 2-fold greater than hydrogels without protein polymer contrast agent. In the absence of the protein polymer contrast agent, hydrogels cannot be distinguished by the end of the gel lifetime.

Biological performance of mussel-inspired adhesive in extrahepatic islet transplantation.

There is significant need for effective medical adhesives that function reliably on wet tissue surfaces with minimal inflammatory insult. To address these performance characteristics, we have generated a synthetic adhesive biomaterial inspired by the protein glues of marine mussels. In-vivo performance was interrogated in a murine model of extrahepatic syngeneic islet transplantation, as an alternative to standard portal administration. The adhesive precursor polymer consisted of a branched poly(ethylene glycol) (PEG) core, whose endgroups were derivatized with catechol, a functional group abundant in mussel adhesive proteins. Under oxidizing conditions, adhesive hydrogels formed in less than 1 min from catechol-derivatized PEG (cPEG) solutions. Upon implantation, the cPEG adhesive elicited minimal acute or chronic inflammatory response in C57BL6 mice, and maintained an intact interface with supporting tissue for up to one year. In-situ cPEG adhesive formation was shown to efficiently immobilize transplanted islets at the epididymal fat pad and external liver surfaces, permitting normoglycemic recovery and graft revascularization. These findings establish the use of synthetic, biologically-inspired adhesives for islet transplantation at extrahepatic sites.

The epididymal fat pad as a transplant site for minimal islet mass.

The epididymal fat pad was evaluated as a site of islet transplantation in a syngeneic murine model of diabetes by comparing the transplant outcomes to that of islets transplanted intraportal. Mouse islets engrafted on the intra-abdominal epididymal fat pad ameliorated streptozotocin-induced hyperglycemia with similar efficacy as grafts implanted intraportally. Mice that received as few as 50 islets, either intraportal or in the epididymal fat pad, displayed similar glucose tolerance curves. Bioluminescence imaging and glucose measurement showed stable luminescence signals and blood glucose levels for over 5 months in both transplant sites using transgenic luciferase-positive islets. Prompt recurrent hyperglycemia occurred in all mice after removal of the epididymal fat pad bearing the islet graft. Histological examination of the grafts showed well-granulated insulin containing cells surrounded by healthy adipocytes. This study indicates that the epididymal fat pad maybe a useful islet transplant site in the mouse model for effective glycemic control.

Glucose and lipid metabolism after liver transplantation in inbred rats: consequences of hepatic denervation.

The liver plays a central role in glucose and lipid homeostasis. Because liver transplantation severs the hepatic nerves which influence this function, we hypothesized that insulin resistance and hyperlipidemia develop after liver transplantation, thus increasing the atherosclerotic risk. Therefore, we studied inbred rats 8 months after orthotopic liver transplantation (Tx, n = 39) or laparotomy (sham, n = 37) by either oral glucose tolerance test (Tx, n = 13; sham, n = 8), meal tolerance test (Tx, n = 9; sham, n = 13), or euglycemic hyperinsulinemic clamp with tritiated glucose infusion (Tx, n = 17; sham, n = 16). We found that liver transplantation significantly increased basal hepatic glucose production (HGP) in the clamp study by 20% (37.3 +/- 2.2 vs 31.0 +/- 2.1 micromol kg -1 .min -1 , P < .05) and fasting plasma low-density lipoprotein (LDL) cholesterol by 36% (0.79 +/- 0.06 vs 0.58 +/- 0.05 mmol/L, P < .05). However, it did not affect HGP, total glucose uptake, metabolic clearance rate of insulin, and suppression of plasma nonesterified fatty acids, which were all normal in response to rising plasma insulin concentrations in the dose-response clamp studies. The oral glucose tolerance test and meal tolerance test also showed normal glucose and nonesterified fatty acids homeostasis with adequate pancreatic insulin secretion and hepatic insulin clearance after liver transplantation. The only consequences of liver transplantation are increased basal HGP and plasma LDL cholesterol, which may be caused by persistent vagal denervation of the liver. Although insulin resistance is absent, elevated plasma LDL cholesterol increases the atherosclerotic risk.

Effects of portal vein arterialization on regeneration and morphology in liver transplantation: investigations using the rat model.

BACKGROUND: Portal vein arterialization (PVA) has been proposed as a technical variant in liver transplantation in the case of non-recanalizable thrombosis. The present study investigates the effects of the arterialized portal vein on the function, morphology, and regenerative behavior of the liver. METHODS: Different PVA techniques, including orthotopic liver transplantation, were used in a rat model. Portal blood flow was measured using a ultrasonic flowmeter. The regeneration capacity was determined on the basis of the increase of liver weight and the proliferating cell nuclear antigen index. The amount of hydroxyproline and the transcript levels of procollagen I were measured to determine the degree of fibrosis. The extracellular matrix was visualized with Picro-Sirius staining. RESULTS: The measurements obtained with an ultrasonic probe revealed a significant increase in portal blood flow after PVA. The regeneration capacity in the groups after PVA with no flow reduction was comparable to that of the control. Liver transplantation and PVA with no flow reduction was followed by a significant increase (four- to sixfold) in the amount of hydroxyproline and the level of the mRNA for procollagen I. In the Picro-Sirius staining, periportal and perivascular fibrosis with incipient formation of septa was seen. After reduction of the portal blood flow, these effects were significantly less pronounced. CONCLUSIONS: These operative techniques represent an excellent small animal model for studying the mechanism of liver regeneration and the genesis of fibrosis in liver and vessel tissue. The presenting findings indicate that the negative effects of "overarterialization" may be largely avoided by reducing portal blood flow. This implies that permanent PVA in clinical liver transplantation should be performed only in conjunction with a down-regulation of portal flow.

Impact of changing immunosuppressive monotherapy from Cyclosporin A to Tacrolimus in long-term, stable liver transplant recipients.

A number of studies have reported a lower atherogenic lipid profile in liver transplant recipients under tacrolimus (FK506) than in those under cyclosporine A (CyA) immunosuppression. This has mainly been attributed to the steroid-saving effect of FK506. However, the effects of converting CyA to FK506 monotherapy on lipid metabolism have not been specifically investigated. In 20 patients with stable graft function, immunosuppressive monotherapy was switched from CyA to FK506 because of CyA-related side-effects (hypertension, nephrotoxicity, hypercholesterolaemia). Serum lipid levels were measured before and 3, 6 and 12 months after conversion. In 5 patients, a modification of immunosuppression became necessary during the study period (4 were reconverted to CyA, 1 to glucocorticoids). In the remaining 15 patients on FK506 monotherapy, 12 months after conversion, a slight decrease in mean serum cholesterol, a slight increase in LDL, but a significant decrease in mean serum HDL were observed, resulting in a significant increase in Chol/HDL and LDL/HDL ratios. Conversion of immunosuppressive monotherapy from CyA to FK506 had no beneficial effect on the atherogenic lipid profile in this selected study population of long-term liver transplant survivors.

Outcome of patients with pre-existing portal vein thrombosis undergoing arterialization of the portal vein during liver transplantation.

Arterialization of the portal vein is being propagated as a technical possibility in liver transplant recipients with pre-existing portal vein thrombosis. In our own small series, portal vein arterialization (PVA) was carried out in four patients undergoing orthotopic liver transplantation. In three of these cases, the portal vein was anastomosed to the aorta via an interposed iliac artery, and in one case, directly to the hepatic artery. After PVA, all transplants showed regular initial function. Two patients died postoperatively after 19 and 50 days, of intra-abdominal haemorrhage and liver necrosis with thrombosis of the portal vein, respectively. A further patient had previously developed fibrosis of the liver, which led to the death of the patient 11 months after PVA. In the remaining patient, chronic rejection requiring re-transplantation developed 24 months after PVA had been performed. These unfavourable results prompt the conclusion that PVA cannot be recommended as a standard clinical procedure.