First-in-class MKK4 inhibitors enhance liver regeneration and prevent liver failure

Diminished hepatocyte regeneration is a key feature of acute and chronic liver diseases and after extended liver resections, resulting in the inability to maintain or restore a sufficient functional liver mass. Therapies to restore hepatocyte regeneration are lacking, making liver transplantation the only curative option for end-stage liver disease. Here, we report on the structure-based development and characterization (nuclear magnetic resonance [NMR] spectroscopy) of first-in-class small molecule inhibitors of the dual-specificity kinase MKK4 (MKK4i). MKK4i increased liver regeneration upon hepatectomy in murine and porcine models, allowed for survival of pigs in a lethal 85% hepatectomy model, and showed antisteatotic and antifibrotic effects in liver disease mouse models. A first-in-human phase I trial (European Union Drug Regulating Authorities Clinical Trials [EudraCT] 2021-000193-28) with the clinical candidate HRX215 was conducted and revealed excellent safety and pharmacokinetics. Clinical trials to probe HRX215 for prevention/treatment of liver failure after extensive oncological liver resections or after transplantation of small grafts are warranted.

Comprehensive analysis of brain injury parameters in a preclinical porcine model of acute liver failure

Introduction

Acute liver failure (ALF) is defined as acute loss of liver function leading to hepatic encephalopathy associated with a high risk of patient death. Brain injury markers in serum and tissue can help detect and monitor ALF-associated brain injury. This study compares different brain injury parameters in plasma and tissue along with the progression of ALF.

Method

ALF was induced by performing an 85% liver resection. Following the resection, animals were recovered and monitored for up to 48 h or until reaching the predefined endpoint of receiving standard medical therapy (SMT). Blood and serum samples were taken at Tbaseline, T24, and upon reaching the endpoint (Tend). Control animals were euthanized by exsanguination following plasma sampling. Postmortem brain tissue samples were collected from the frontal cortex (FCTx) and cerebellum (Cb) of all animals. Glial fibrillary acidic protein (GFAP) and tau protein and mRNA levels were quantified using ELISA and qRT-PCR in all plasma and brain samples. Plasma neurofilament light (NFL) was also measured using ELISA.

Results

All ALF animals (n = 4) were euthanized upon showing signs of brain herniation. Evaluation of brain injury biomarkers revealed that GFAP was elevated in ALF animals at T24h and Tend, while Tau and NFL concentrations were unchanged. Moreover, plasma glial fibrillary acidic protein (GFAP) levels were negatively correlated with total protein and positively correlated with both aspartate transaminase (AST) and alkaline phosphatase (AP). Additionally, lower GFAP and tau RNA expressions were observed in the FCTx of the ALF group but not in the CB tissue.

Conclusion

The current large animal study has identified a strong correlation between GFAP concentration in the blood and markers of ALF. Additionally, the protein and gene expression analyses in the FCTx revealed that this area appears to be susceptible, while the CB is protected from the detrimental impacts of ALF-associated brain swelling. These results warrant further studies to investigate the mechanisms behind this process.

Clinical characterization of a hypersensitivity mixed bacterial and fungal dermatitis in a translational model of porcine NASH

Introduction

The development of animal models of chronic liver disease via diet modification is a promising avenue for translational research but can lead to unexpected side effects that impact model adoption. While these side effects are well characterized in rodent models of nonalcoholic steatohepatitis (NASH), limited knowledge of these effects exists for novel porcine models of NASH. To close this gap, the present study investigates the side effects of diet-based NASH induction in pigs, with a systematic analysis of the pathologic mechanisms underlying dermatitis development and evaluation of treatment approaches.

Method

Twelve pigs (10 large domestic pigs, 2 Goettingen minipigs) were fed a methionine- and choline-deficient, high-fat diet for 8 weeks to induce NASH. A retrospective review of each animal's clinical record was performed to identify the side effects of the diet. Following the identification of diet-associated dermatitis, severity was judged by using a novel gradation system that characterized the individual lesions and body regions resulting in a cumulative evaluation. In addition to this clinical assessment, the etiology of the dermatitis was investigated via histopathologic and microbiologic testing. Furthermore, the success of prophylactic and therapeutic treatment approaches was evaluated by considering dermatitis development and clinical course.

Results

All study animals demonstrated unexpected side effects of the methionine- and choline-deficient, high fat diet. In addition to marked dermatitis, study pigs showed impaired weight gain and developed steatorrhea and anemia. Based on the skin gradation system, five animals developed severe dermatitis, four animals moderate dermatitis, and three animals mild diet-associated dermatitis. Histological and microbiological evaluation of the affected skin showed signs of a hypersensitivity reaction with secondary infection by bacteria and fungi. The analysis showed that preemptive bathing extended the lesion-free duration by nearly 20 days. Furthermore, bathing in combination with a targeted antibiotic treatment represented a helpful treatment approach for diet-associated dermatitis.

Conclusion

The provision of a methionine- and choline-deficient, high fat diet represents an effective approach for inducing NASH liver disease in pigs but predisposes study animals to multiple side effects. These side effects are universal to animals on study but can be adequately managed and do not represent a significant limitation of this model.

Pathogen detection in patients with perihilar cholangiocarcinoma: Implications for targeted perioperative antibiotic therapy

BACKGROUND

Cholestasis should be relieved by biliary drainage prior to major liver resection. This condition is often associated with bacterial colonization of the otherwise sterile biliary system. Cholangitis reduces the regenerative capacity of the remaining liver. Therefore, targeted antibiotic therapy is a key feature in perioperative treatment in patients with perihilar cholangiocarcinoma (pCCC).

METHODS

Between December 1999 and December 2017, 251 pCCC patients were treated in our center. In total, 115 patients underwent a microbiological analysis. In addition to the characterization of the specific microorganisms and antibiotic resistance, we analyzed subgroups according to preoperative intervention.

RESULTS

Enterococci (87/254, 34%) and Enterobacteria (65/254, 26%) were the most frequently detected genera. In 43% (50/115) of patients, Enterococcus faecalis was found in the bile duct sample. Enterococcus faecium (29/115) and Escherichia coli (29/115) were detected in 25% of patients. In patients with percutaneous transhepatic biliary drainage (3/8, 38%) or stents (24/79, 30%), Enterococcus faecium was diagnosed most frequently (P < 0.05). Enterococcus faecium and Klebsiella oxytoca were significantly more frequently noted in the time period after 2012 (P < 0.05). With regard to fungal colonization, the focus was on various Candida strains, but these strains generally lacked resistance.

CONCLUSIONS

pCCC patients exhibit specific bacterial colonization features depending on the type of preoperative biliary intervention. Specifically, targeted antibiosis should be applied in this patient cohort to minimize the risk of biliary complications after major liver resection. In our cohort, the combination of meropenem and vancomycin represents an effective perioperative medical approach.

Biodegradable biliary stents coated with mesenchymal stromal cells in a porcine choledochojejunostomy model

BACKGROUND AIMS

Roux en y anastomosis is a preferred method of biliary reconstruction in liver transplantation that involves living donors or pediatric patients. However, biliary stricture is a frequent and serious complication, accounting for up to 40% of biliary complications in these patients. Previously, we demonstrated that extraluminal delivery of adipose-derived (AD) mesenchymal stromal cells (MSCs) decreased peri-biliary fibrosis and increased neo-angiogenesis in a porcine model of duct-to-duct biliary anastomosis. In this study, we used a porcine model of Roux en y anastomosis to evaluate the beneficial impact of a novel intraluminal MSC delivery system.

METHODS

Nine animals were divided into three groups: no stent (group 1), bare stent (group 2) and stent coated with AD-MSCs (group 3). All animals underwent cholecystectomy with roux en y choledochojejunostomy. Two animals per group were followed for 4 weeks and one animal per group was followed for 8 weeks. Cholangiograms and blood were sampled at baseline and the end of study. Biliary tissue was collected and examined by Masson trichrome staining and immunohistochemical staining for MSC markers (CD34 and CD44) and for neo-angiogenesis (CD31).

RESULTS

Two of three animals in group 1 developed an anastomotic site stricture. No strictures were observed in the animals of group 2 or group 3. CD34 and CD44 staining showed that AD-MSCs engrafted successfully at the anastomotic site by intraluminal delivery (group 3). Furthermore, biliary tissue from group 3 showed significantly less fibrosis and increased angiogenesis compared with the other groups.

CONCLUSIONS

Intraluminal delivery of AD-MSCs resulted in successful biliary engraftment of AD-MSCs as well as reduced peri-biliary fibrosis and increased neo-angiogenesis.

Re-Endothelialization of Decellularized Liver Scaffolds: A Step for Bioengineered Liver Transplantation

Bioengineered livers (BELs) are an attractive therapeutic alternative to address the donor organ shortage for liver transplantation. The goal of BELs technology aims at replacement or regeneration of the native human liver. A variety of approaches have been proposed for tissue engineering of transplantable livers; the current review will highlight the decellularization-recellularization approach to BELs. For example, vascular patency and appropriate cell distribution and expansion are critical components in the production of successful BELs. Proper solutions to these components of BELs have challenged its development. Several strategies, such as heparin immobilization, heparin-gelatin, REDV peptide, and anti-CD31 aptamer have been developed to extend the vascular patency of revascularized bioengineered livers (rBELs). Other novel methods have been developed to enhance cell seeding of parenchymal cells and to increase graft functionality during both bench and in vivo perfusion. These enhanced methods have been associated with up to 15 days of survival in large animal (porcine) models of heterotopic transplantation but have not yet permitted extended survival after implantation of BELs in the orthotopic position. This review will highlight both the remaining challenges and the potential for clinical application of functional bioengineered grafts.

Ligation of the middle hepatic vein to increase hypertrophy induction during the ALPPS procedure

PURPOSE

Here, we analyse the technical modification of the ALPPS procedure, ligating the middle hepatic vein during the first step of the operation to enhance remnant liver hypertrophy.

METHODS

In 20 of 37 ALPPS procedures, the middle hepatic vein was ligated during the first step. Hypertrophy of the functional remnant liver volume was assessed in addition to postoperative courses.

RESULTS

Volumetric analysis showed a significant volume increase, especially for patients with colorectal metastases. Pre-existing liver parenchyma damage (odds ratio = 0.717, p = 0.017) and preoperative chemotherapy were found to be significant predictors (odds ratio = 0.803, p = 0.045) of higher morbidity and mortality. In addition, a survival benefit for maintenance of middle hepatic vein was shown.

CONCLUSION

This technical modification of the ALPPS procedure can accentuate future liver remnant volume hypertrophy. The higher morbidity and mortality observed are most likely associated with pre-existing parenchymal damage within this group.

Identification of tissue sections from decellularized liver scaffolds for repopulation experiments

BACKGROUND

Biological organ engineering is a novel experimental approach to generate functional liver grafts by decellularization and repopulation. Currently, healthy organs of small or large animals and human organs with preexisting liver diseases are used to optimize decellularization and repopulation.However, the effects of morphological changes on allo- and xenogeneic cell-scaffold interactions during repopulation procedure, e.g., using scaffold-sections, are unknown. We present a sequential morphological workflow to identify murine liver scaffold-sections with well-preserved microarchitecture.

METHODS

Native livers (CONT, n = 9) and livers with experimentally induced pathologies (hepatics steatosis: STEA, n = 7; hepatic fibrosis induced by bile duct ligation: BDL, n = 9; nodular regenerative hyperplasia induced by 90% partial hepatectomy: PH, n = 8) were decellularized using SDS and Triton X-100 to generate cell-free scaffolds. Scaffold-sections were assessed using a sequential morphological workflow consisting of macroscopic, microscopic and morphological evaluation: (1) The scaffold was evaluated by a macroscopic decellularization score. (2) Regions without visible tissue remnants were localized for sampling and histological processing. Subsequent microscopical examination served to identify tissue samples without cell remnants. (3) Only cell-free tissue sections were subjected to detailed liver-specific morphological assessment using a histological and immunohistochemical decellularization score.

RESULTS

Decellularization was feasible in 33 livers, which were subjected to the sequential morphological workflow. In 11 of 33 scaffolds we achieved a good macroscopic decellularization result (CONT: 3 scaffolds; STEA: 3 scaffolds; BDL: 3 scaffolds; PH: 2 scaffolds). The microscopic assessment resulted in the selection of 88 cell-free tissue sections (CONT: 15 sections; STEA: 38 sections; BDL: 30 sections; PH: 5 sections). In 27 of those sections we obtained a good histological decellularization result (CONT: 3 sections; STEA: 6 sections; BDL: 17 sections; PH: 1 section). All experimental groups contained sections with a good immunohistochemical decellularization result (CONT: 6 sections; STEA: 5 sections; BDL: 4 sections; PH: 1 section).

DISCUSSION

Decellularization was possible in all experimental groups, irrespectively of the underlying morphological alteration. Furthermore, our proposed sequential morphological workflow was suitable to detect tissue sections with well-preserved hepatic microarchitecture, as needed for further repopulation experiments.

Liver Transplant Due to Flupirtine-Induced Acute Liver Failure

OBJECTIVES

Acute drug-induced liver failure is a rare indication for liver transplant. There is only one case of flupirtine-induced liver failure requiring transplant in the literature. In February 2018, the European Medicines Agency issued a withdrawal of approval for flupirtine medication in European countries as a result of the risk of acute liver failure.

MATERIALS AND METHODS

The aim of this study was a German-wide collection of data regarding patients with liver transplant as a result of flupirtine-associated liver failure.

RESULTS

A total of 9 patients received transplants. All patients were women with a mean age of 43 years. Indication for flupirtine medication was musculoskeletal symptoms and migraine headache. The medication was taken over a period of approximately 3 months. All patients developed progressive acute liver failure, and no patient had previous chronic liver disease or cirrhosis. The mean laboratory Model for End Stage Liver Disease score for the patients was 31 ± 7 at time of transplant. Eight of the 9 patients were listed as "high urgency" for transplant. After transplant, they had an uneventful course with a prolonged mean intensive care unit stay of 13 ± 8.7 days. The whole hospitalization time was 43 ± 21 days.

CONCLUSIONS

This is the largest published series of patients who received liver transplant after a drug-induced acute liver failure from flupirtine medication.

Milan criteria in the MELD era-is it justifiable to extend the limits for orthotopic liver transplantation?

Background

The Milan criteria (MC) are widely used for the indication of liver transplantation (LTx) in hepatocellular carcinoma (HCC). Good long-term results have also been reported following LTx for patients exceeding the MC. In this article, we compare the overall and recurrence-free survival of our patients fulfilling and exceeding the MC according to the post-transplant histopathological results.

Patients and methods

Data from 120 patients with HCC (22 females and 98 males) were analyzed. The median patient age was 61 years (Q1, Q3 54.7, 65.4), and the median MELD score was 11 (Q1, Q3 8, 15). The median follow-up period was 53 months (Q1, Q3 16.6, 78). Patients were categorized into established criteria (MC, up-to-seven (UTS), Asan criteria, AFP score), and the outcome of the individual groups was compared.

Results

Seventy-four of 120 patients fulfilled the MC, 86 patients met the UTS criteria, 85 patients fulfilled the Asan criteria, and 79 patients had an AFP score less than or equal to 2. The 1- and 5-year survival rates of all patients were 76.7% and 55.6%, respectively. In total, 14.2% of all patients (5.4% of patients who met the MC, 7% of patients who met the UTS criteria, 5.9% of patients who met the Asan criteria, and 6.3% of patients who had an AFP score less than 2) experienced recurrence.

Conclusions

The outcomes of the patients were comparable to those reported in the current literature. In our population, similar recurrence and survival rates of the patients were noted for patients fulfilling the UTS criteria irrespective of fulfilling or exceeding the MC. Consequently, we consider using UTS criteria as the extended criterion for LTx indication.

[Video-based Analysis of Practical Skills - a Suitable Tool to Develop Surgical Training?]

BACKGROUND

Video-based analysis concepts are being is increasingly applied in medical education. These tools are mainly used to obtain information about the individual performance of a candidate and to provide feedback. The present study explores whether video-based analysis of practical skills can also be used for the development of surgical training.

METHODS

First, the performance of students in semester 10 (n = 38) in a surgical suture exercise (duration: 3 min) was video-documented. The video material was then analysed using 10 specific criteria. The analysis then served as a basis for the development of error prevention exercises. In the following, the effects of the additional teaching units on the performance in the suture exercise were examined in a pilot study using a two-group comparison.

RESULTS

The video sequences were reviewed independently by 2 experts. Typical errors could be observed in the handling of the surgical instruments, the handling of the suture material as well as in the motion sequence. Then, additional teaching units dealing with the identified error areas (handling of the instruments and the suture material) were developed. The results of the two-group comparison (before and after implementation of the new exercises) showed that completing the additional teaching units had a medium effect on the result quality of the suture exercise (Cohen's d = 0.73).

CONCLUSION

Video analysis of practical skills seems to be a suitable basis for the development of surgical training. Typical errors can be identified in terms of type and frequency, and preventive exercises can be developed, which have a positive effect on the quality of the results of a practical task.

The impact of immunosuppression on postoperative graft function after graft-unrelated surgery: a retrospective controlled cohort study

Background

Physicians are faced with a growing number of patients after renal transplantation undergoing graft-unrelated surgery. So far, little is known about the postoperative restitution of graft function and the risk factors for a poor outcome.

Methods

One hundred one kidney transplant recipients undergoing graft-unrelated surgery between 2005 and 2015 were reviewed retrospectively. A risk analysis was performed and differences in creatinine, GFR and immunosuppressive treatment were evaluated. Additional, a comparison with a case-matched non-transplanted control group were performed.

Results

Preoperative creatinine averaged 1.88 mg / dl [0.62–5.22 mg / dl] and increased to 2.49 mg / dl [0.69–8.30 mg / dl] postoperatively. Acute kidney failure occurred in 18 patients and 14 patients had a permanent renal failure. Significant risk factors for the development of postoperative renal dysfunction were female gender, a preoperative creatinine above 2.0 mg / dl as well as a GFR below 40 ml / min and emergency surgery. Patients with tacrolimus and mycophenolate mofetil treatment showed a significant lower risk of renal dysfunction than patients with other immunosuppressants postoperatively. Contrary to that, the risk of patients with cyclosporine treatment was significantly increased. Transplanted patients showed a significantly increased rate of postoperative renal dysfunction.

Conclusions

The choice of immunosuppressant might have an impact on graft function and survival of kidney transplant recipients after graft-unrelated surgery. Further investigations are needed.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1358-2) contains supplementary material, which is available to authorized users.

Liver Transplant for Perihilar Cholangiocarcinoma (Klatskin Tumor): The Essential Role of Patient Selection

OBJECTIVES

Perihilar cholangiocarcinoma (Klatskin tumor) is a rare tumor entity, which is diagnosed late due to uncharacteristic symptoms. The therapeutic strategy for cure is still liver resection. Liver transplant in cases of locally irresectable tumors represents an alternative potential curative therapy for a select group of patients.

MATERIALS AND METHODS

We present our data of 22 patients with irresectable Klatskin tumors who received transplants between 1996 and 2015. We analyzed relevant prognostic factors for the selection of patients to be transplanted to ensure an acceptable overall survival and reviewed known and established selection criteria.

RESULTS

Four factors (age, tumor size, serum level of carbohydrate antigen 19-9, percutaneous transhepatic cholangiodrainage) could be detected for possible patient selection. Positive lymph node status and advanced tumor stage according to the Union for International Cancer Control were confirmed as negative prognostic factors for survival after transplant.

CONCLUSIONS

Liver transplant is a curative therapy for selected patients with irresectable Klatskin tumors, but further prospective studies are urgently needed.

The value of microparticles in detecting acute rejection episodes after liver transplantation

CONTEXT

Non-invasive markers for diagnosis of acute rejection (AR) following liver transplantation have not been developed, yet.

OBJECTIVE

We analyzed the correlation of plasma microparticle levels (MP) with AR.

MATERIALS AND METHODS

MP (CD4, CD8, CD25, CD31, MHC) of 11 AR patients and 11 controls were analyzed within the first week after transplantation.

RESULTS

CD4, CD8 and CD31 positive MP were higher in the AR, whereas overall MP count, CD25 and MHCI positive MP proportions did not differ between both groups.

DISCUSSION AND CONCLUSION

MP dynamics within the first period of transplantation could help to clarify on-going mechanisms of immunomodulation.