Zoltan Mathe

Vitamin D counteracts fibrogenic TGF-β signalling in human hepatic stellate cells both receptor-dependently and independently

Objective Non-alcoholic fatty liver disease (NAFLD) is closely linked to obesity and constitutes part of the metabolic syndrome, which have been associated with low serum vitamin D (VD). Due to known crosstalk between VD and transforming growth factor (TGF)-β signalling, VD has been proposed as an antifibrotic treatment. Design We evaluated the association between VD, the vitamin D receptor (VDR) and liver fibrosis in primary human hepatic stellate cells (phHSC) and 106 morbidly obese patients with NAFLD. Results Treating phHSC with VD ameliorated TGF-β-induced fibrogenesis via both VDR-dependent and VDR-independent mechanisms. Reduction of fibrogenic response was abolished in cells homozygous for GG at the A1012G single nucleotide polymorphisms within the VDR gene. Compared with healthy livers, NAFLD livers expressed higher levels of VDR mRNA and VDR fragments. VDR mRNA was lower in patients homozygous for GG at A1012G and expression of pro-fibrogenic genes was higher in patients carrying the G allele. Conclusions VD may be an antifibrotic treatment option early in the onset of fibrosis in specific genotypes for VDR. Known polymorphisms of the VDR may influence the response to VD treatment.

Effect of microcapsule composition and short-term immunosuppression on intraportal biocompatibility

With higher nutrient and oxygen supply and close contact to blood, the portal vein is a possible alternative to the peritoneal cavity for transplantation of encapsulated cells. Data regarding intraportal biocompatibility of microcapsules are lacking. Microcapsules were built from five alginate types differing in their molar mass and mannuronic/guluronic acid ratios by complex formation with divalent cations (barium or calcium) or mixtures of divalent cations and polycations. They were injected in the portal vein of rats, and cellular and fibrotic pericapsular infiltration thickness was measured 3 and 7 days after implantation. Overgrowth was characterized using various stainings or immunohistochemistry (hematoxylin and eosin, Giemsa, ED-1 for monocyte/macrophage, α-actin for myofibroblasts, CD31 for endothelial cells). The impact of short-term immunosuppression (gadolinium-chloride IV 20 mg/kg/day on days −1 and 4 as well as 10 days of rapamycin PO 1 mg/kg/day, tacrolimus PO 3 mg/kg/day, or combinations of rapamycin/tacrolimus or gadolinium/tacrolimus) was further assessed 3, 7, and 42 days after implantation. Overall, overgrowth increased from day 3 to day 7 (p < 0.05). Three and 7 days after implantation, polycation-containing microcapsules induced more reaction than microbeads (p < 0.0001 and p < 0.01). Considering polycation-free beads, barium-alginate induced the weakest reaction. Biocompatibility of microbeads was independent of mannuronic/guluronic acid ratio and molar mass of the alginate. Infiltration was mainly a monocyte/macrophage-rich foreign body reaction, but an eosinophil-containing immunoallergic reaction was also observed. Short-term immunosuppression significantly reduced infiltration in all conditions and up to 42 days after implantation. Biocompatibility after intraportal infusion was best for barium-alginate microbeads and poorest for polycation-containing microcapsules. Short- and long-term overgrowth could be significantly reduced by short-term immunosuppression.

Liver transplantation for hepatic metastases of neuroendocrine pancreatic tumors: a survival-based analysis.

Background. Liver transplantation (LT) has been accepted as a treatment in selected cases of neuroendocrine tumors (NETs) with hepatic metastases. Patients and Methods. A systematic review of the literature was conducted to evaluate long-term patient survival in the instances of LT for pancreatic NET. Univariate and multivariate regression analyses and survival analysis were performed. Results. Fifty-three clinical studies were screened. Data from 20 studies encompassing 89 transplanted patients were included in the study. Most primary tumors were endocrine pancreatic tumors (n=69), with gastrinomas representing the most frequent diagnosis (n=21). There were 61 functioning pancreatic NET. Simultaneous LT and pancreatic NET resections were performed in 45 instances. Cumulative 1-, 3-, and 5-year survival was 71%, 55%, and 44%, respectively, with a calculated mean survival of 54.45±6.31 months. Vasoactive intestinal peptide (VIPomas) had the best overall survival. Recurrence-free survival at 1, 3, and 5 years was 84%, 47%, and 47%, respectively. Recipient age more than or equal to 55 years (P=0.0242) and simultaneous LT-pancreatic resection (P=0.0132) were found to be significant predictors of worse survival by both univariate and multivariate Cox proportional hazard analyses. A scoring system was developed, with prognostic points assigned as follows: age more than or equal to 55 years:age less than 55years=1:0 points and simultaneous LT-pancreatic resection:LT alone=1:0 points. This stratification delineated three separate population samples corresponding to patients with scores of 0, 1, and 2, respectively. The calculated 5-year survival for scores 0, 1, and 2 was 61%, 40%, and 0%, respectively (P=0.0023). Conclusions. Despite the limitations of this retrospective analysis, good results can be achieved even for pancreatic NET primaries if the above-proposed scoring system is applied.

Liver Transplantation in Nonalcoholic Steatohepatitis Is Associated with High Mortality and Post-Transplant Complications: A Single-Center Experience

Background/Aims: Non-alcoholic fatty liver disease (NAFLD) with its progressive form nonalcoholic steatohepatitis (NASH) is the most common chronic liver disease in western countries which is associated with end-stage liver disease and hepatocellular carcinoma (HCC). This entity is a consistently increasing indication for transplantation. However, data about postsurgery outcome and complications are still limited. Patients and Methods: Records of 432 consecutive transplanted patients between October 2007 and January 2011 were investigated retrospectively. Forty transplants were performed due to NASH-induced cirrhosis. Perioperative courses and short- and long-term outcomes were analyzed. Results: The NAFLD population consisted of 16 women and 24 men with a mean age of 55 years. The median MELD score was 27 at the time of liver transplantion. BMI before surgery ranged from 21 to 45 (mean 31). Sixteen of the initial 40 patients are still alive. Patients with sustained obesity and features of the metabolic syndrome had a worse 1-year mortality rate of 42%. Conclusions: A significant number of liver transplantations in our center was performed due to NASH; transplantation in this cohort was associated with high mortality and postoperative complications, most likely due to associated obesity and diabetes. Weight reduction prior to surgery may lead to a better outcome.

Controlled Oxygenated Rewarming of Cold Stored Livers Prior to Transplantation: First Clinical Application of a New Concept.

Background Abrupt temperature shift from hypothermia to normothermia incurred on reperfusion of organ grafts has been delineated as a genuine factor contributing to reperfusion injury and graft dysfunction after transplantation. Methods In a first clinical series of 6 patients, cold-stored livers, all allocated by the rescue offer mechanism by Eurotransplant, were subjected to machine-assisted slow controlled oxygenated rewarming (COR) for 90 minutes before engrafting. A historical cohort of 106 patients basically similar in graft (all rescue offer organs) and recipient factors was used for comparison. Results The clinical benefit of COR was documented by a significant reduction by approximately 50% in peak serum transaminases after transplantation compared to untreated controls (AST 563.5 vs 1204 U/L, P = 0.023). After 6 months graft survival was 100% in the COR group and 80.9% in the controls (P = 0.24). Respective patient survival was 100% and 84.7% (P = 0.28). Real-time assessment of glucose concentration in the perfusion solution correlated well with postoperative synthetic graft function (r2 = 0.78; P < 0.02). All treated recipients had normal liver function after a 6-month follow-up and are well and alive. Conclusions This first clinical application suggests that controlled graft rewarming after cold storage is a feasible and safe method in clinical praxis and might become an adjunct in organ preservation.

Attitudes of donors towards organ transplantation in living related kidney transplantations

Abstract The demand for transplantation exceeds the availability of cadaveric organs, which is why the importance of living, related kidney transplantation is increasing. In our study we wanted to evaluate the experiences of living related donors (LRD). Between 1973 and 1996, 1325 kidney transplantations were performed at our Department. Of these 1247 were from cadaver donors while 78 were from LRD. We contacted each living donor by post. We carried out a physical examination, laboratory tests, ultrasound and isotope investigations and they were interviewed and completed a questionnaire. Thirty previous kidney donors came to our Department who were all blood relatives of the recipients. In the recipient group, 16 still have a functioning kidney, the average time since transplantation being 8.92 years. The longest kidney survival time is 18 years. All the donors willingly donated their kidney, none was worried about their own health and their only concern was whether the kidney would function or not. Regarding general attitudes towards living related organ transplantation, all were in favour of blood relative donor transplantation and also husband/wife transplantation. Opinions regarding non‐related transplantation were more mixed; 63.3% would have given their kidneys to a friend, only 46.6% to a stranger. Almost two‐thirds (63.3%) of donors were not in favour of selling and buying organs but, controversially, they would have bought an organ had one been available. All agreed that the donation did not change their general health. In conclusion, the donors of living, related kidney transplantation all agreed that it was a good thing to donate; All confirmed they would go through the same procedure again in order to help. Apart from one person, who emphasised that he is agnostic, all belonged to a Christian religion.

Macrophage depletion prolongs discordant but not concordant islet xenograft survival

Background. T cells and macrophages play a major role in the rejection of xenografted islets. Depending on the phylogenetic disparity, direct or indirect antigen presentation is predominant. The aim of this study was to analyze in vitro the predominance of direct or indirect presentation by depleting antigen-presenting cells in concordant and discordant xenogeneic combinations. In vivo, we analyzed the effect of macrophage depletion on concordant and discordant islet xenograft survival to assess in which combination this strategy can be used as therapeutic tool. Materials and Methods. In vitro, we performed mouse anti-rat and anti-human mixed lymphocyte reactions (MLR) after depletion of responder or stimulator antigen-presenting cells by magnetic sorting. In vivo, streptozotocin-induced diabetic C57BL/6 mice were treated by gadolinium chloride (GdCl) to deplete macrophages, and rat or human islets were transplanted under the kidney capsule. Islet function was followed by glycemia, and xenografts were analyzed at regular intervals for histology and immunohistochemistry. Results. Mouse anti-rat MLR showed a predominant direct antigen presentation pathway, whereas in mouse anti-human MLR, direct and indirect pathways were similarly involved. Survival of rat islets was not modified by GdCl therapy. In contrast, survival of human islets was significantly prolonged in GdCl-treated mice. Macrophage infiltration was decreased in concordant and discordant GdCl-treated xenografts at day 4 compared with controls. At day 15, macrophage, CD4+, and CD8+ cell infiltration was similar in all groups. Conclusions. Our results indicate that direct antigen presentation is dominant in the rejection mechanism of concordant islet xenografts and cannot be influenced by host macrophage depletion. Both direct and indirect antigen presentation are involved in rejection of discordant xenogeneic islets. Macrophage depletion should only be considered as therapeutic tool for discordant islet xenotransplantation.

Islet Autotransplantation After Left Pancreatectomy for Non‐Enucleable Insulinoma

Insulinoma is a rare, almost always benign endocrine tumor of the pancreas, clinically characterized by hyperinsulinemic, hypoglycemic episodes. Surgical excision is the therapy of choice, which may lead to postpancreatectomy diabetes mellitus in the case of extensive pancreatic resection.

Donor information based prediction of early allograft dysfunction and outcome in liver transplantation.

Poor initial graft function was recently newly defined as early allograft dysfunction (EAD) [Olthoff KM, Kulik L, Samstein B, et al. Validation of a current definition of early allograft dysfunction in liver transplant recipients and analysis of risk factors. Liver Transpl 2010; 16: 943]. Aim of this analysis was to evaluate predictive donor information for development of EAD.

Microbial surveillance during human pancreatic islet isolation.

The aim of the study was to investigate microbiological contamination rate during human pancreatic islet isolation. Between 1996 and 2002, pancreas preservation media and postpurification islet preparations were screened for microbiological contamination. After arrival in the laboratory, pancreata were washed prior to enzyme perfusion with either Hanks balanced salt solution (Group I, n = 170, 1996 to 2001) or decontaminated with polyvidonum‐iodine, cefazoline, and amphotericine B (Group II, n = 45, 2001 to 2002). Microbiological contamination of preservation media was observed in 56% and 84% for Groups I and II, respectively. Analysis of contaminants revealed 74% Gram‐positive, 21% Gram‐negative bacteria and 5% fungi. Duration of transport had an influence on the rate of contamination (P < 0.05). After islet isolation, Group I presented microbial contamination of 16 islet preparations (9.4%) [i.e. Gram‐positive bacteria (n = 10), Gram‐negative bacteria (n = 4), and fungi (n = 2)]. In Group II, only 2 islet preparations (4.4%) presented microbial contamination. Microbial contamination during pancreas procurement occurs frequently. Most microorganisms are eliminated during islet isolation, and de novo contaminations during islet isolation are rare. Pancreas decontamination reduces the risk of infection of the final islet preparation.