Highlights d The PIDDosome controls hepatocyte ploidy during postnatal development & regeneration d The PIDDosome defines the speed of liver regeneration posthepatectomy d Aneuploidy in the liver correlates with basal ploidy state but is not limited by CASP2 d E2F family members regulate expression of CASP2 and PIDD1 for liver ploidy control

The novel drug PX20606 activates the bile acid receptor FXR and shows beneficial effects in experimental liver cirrhosis: In the liver, it reduces scarring and inflammation, and also widens blood vessels. Thus, PX20606 leads to an improved blood flow through the liver and decreases hypertension of the portal vein. Additionally, PX20606 improves the altered intestinal barrier and decreases bacterial migration from the gut.

Liver regeneration (LR) involves a complex interplay of growth factors and antagonists. In this context, platelet-derived serotonin (5-HT) has been identified as a critical inducer of LR in mice. Clinical evidence for a role of 5-HT in LR in humans is lacking. Accordingly, serum and plasma 5-HT was monitored perioperatively in 60 patients undergoing liver resection, of which 35 served as exploration and 25 as validation sets. Intraplatelet (IP) levels of 5-HT were calculated by subtraction of plasma 5-HT from serum values. Serum markers of liver function were used to evaluate LR and liver dysfunction (LD). In the exploration setting, IP 5-HT levels significantly decreased after liver resection (P < 0.001) and gradually recovered during the first week. IP 5-HT measured before surgery specifically predicted LD in the subsequent 7 days (area under the curve: 0.721; P 5 0.029). Patients suffering from postoperative LD and morbidity were found to have reduced IP 5-HT levels during the entire perioperative period. Furthermore, we validated that reduced preoperative IP 5-HT (<73 ng/mL) was associated with an increased incidence of postoperative LD and morbidity (P 50.045 and P 5 0.021) and were able to demonstrate that IP 5-HT levels were an independent predictor of poor clinical outcome. Conclusions: These findings provide evidence that IP 5-HT correlates with LR in humans: Patients with low IP 5-HT before liver resection suffered from delayed hepatic regeneration. Therefore, IP 5-HT levels may prove a helpful clinical marker to predict postoperative LD and clinical outcome before hepatic resection and initiate suitable interventions. (HEPATOLOGY 2014;60:257-266)

Platelets promote liver regeneration through site-specific serotonin release from dense granules, triggering proliferative signaling in hepatocytes. However, the effects of factors derived from platelet a-granules on liver regeneration are unclear, because a-granules contain bioactive molecules with opposing functions. Because a-granule molecules are stored in separate compartments, it has been suggested that platelets selectively release their a-granule content dependent on the environmental stimulus. Therefore, we investigated the pattern of circulating a-granule molecules during liver regeneration in 157 patients undergoing partial hepatectomy. We measured plasma levels of a-granule-derived factors in the liver vein at the end of liver resection, as well as on the first postoperative day. We observed a rapid accumulation of platelets within the liver after induction of liver regeneration. Platelet count and P-selectin (a ubiquitous cargo of a-granules) were not associated with postoperative liver dysfunction. However, low plasma levels of vascular endothelial growth factor (VEGF), but high levels of thrombospondin 1 (TSP-1), predicted liver dysfunction after resection. Patients with an unfavorable postoperative a-granule release profile (high TSP-1/low VEGF) showed substantially worse postoperative clinical outcomes. The unfavorable postoperative a-granule release profile was associated with increased postoperative portal venous pressure and von Willebrand factor antigen levels as a marker for intrahepatic endothelial dysfunction. Conclusion: The postoperative profile of circulating platelet-derived factors correlates with the ability of the remnant liver to regenerate. Portal venous pressure and intrahepatic endothelial dysfunction might account for the selective granule release profile. Selective modulation of platelet a-granule release in patients may represent an attractive target for therapeutic interventions to improve liver regeneration and clinical outcomes after partial hepatectomy. (HEPATOLOGY 2016;63:1675-1688 P latelets are critically involved not only in hemostasis, but also in inflammation, wound healing and angiogenesis. Through release of their granule content, they orchestrate signal responses in a plethora of target cells, including hepatocytes. Platelets are potent inducers of liver regeneration (LR) after partial hepatectomy and platelet activation as well as granule release increase after liver resection.(1,2) Platelet activation results in the release of dense granules, followed by secretion of a-granule content.(3) Exocytosis of a-granules represents a highly regulated process, involving distinct packaging

Patients with chronic liver disease (CLD) and cirrhosis are at high risk for hepatocellular carcinoma (HCC). Current diagnostic tools for HCC detection include imaging techniques and serum biomarkers such as α-fetoprotein (AFP). Yet, these methods are limited in sensitivity and specificity to accurately detect early HCC. Here we focused on the potential of soluble Axl (sAxl) as a biomarker in CLD patients by analyzing serum samples of 1067 patients and healthy controls from centers in Europe and Asia. We show that serum concentrations of sAxl were significantly increased at early (82.57 ng/mL) and later stages of HCC (114.50 ng/mL) as compared to healthy controls (40.15 ng/mL). Notably, no elevated sAxl levels were detected in patients with CLD including chronic viral hepatitis, autoimmune hepatitis, cholestatic liver disease, or non-alcoholic fatty liver disease versus healthy controls. Furthermore, sAxl did not rise in liver adenomas or cholangiocarcinoma (CCA). Yet, patients with advanced fibrosis (F3) or cirrhosis (F4) showed enhanced sAxl concentrations (F3: 54.67 ng/mL; F4: 94.74 ng/mL). Hepatic myofibroblasts exhibited an increased release of sAxl, suggesting that elevated sAxl levels arise from these cells during fibrosis. Receiver operating characteristic curve analysis of sAxl displayed a strongly increased sensitivity and specificity to detect both cirrhosis (80.8%/92.0%) and HCC (83.3%/86.7%) with an area under the curve of 0.935/0.903 as compared to AFP. In conclusion, sAxl shows high diagnostic accuracy at early stage HCC as well as cirrhosis, thereby outperforming AFP. Importantly, sAxl remains normal in most common CLDs, liver adenomas and CCA.

Background: The analysis of angiogenesis factors in the blood of tumor patients has given diverse results on their prognostic or predictive value. Since mediators of angiogenesis are stored in platelets, their measurement in plasma is sensitive to inadvertent platelet activation during blood processing. Methods: Variants of blood withdrawal and plasma preparation were evaluated by ELISA for the detection of TSP-1, PF-4, VEGF and PD-ECGF. A total of 22 pancreatic cancer patients and 29 healthy volunteers were evaluated. Results: Plasma preparation with the anticoagulant mix of citrate, theophylline, adenosine, dipyridamole (CTAD) and immediate blood processing at 4°C was required for reproducible measurements of TSP-1, PF-4 and VEGF. Blood collection by venflon or inadvertent hemolysis during blood withdrawal caused significantly elevated TSP-1 and PF4 values. When optimized plasma preparation was applied, a significant increase of TSP-1 and VEGF in cancer patients was detected (P = 0.006; P < 0.001). Conclusion: The reliable plasma analysis of circulating platelet-stored angiogenesis factors requires preparation with CTAD at 4°C and blood collection by butterfly needle. Suboptimal procedures of plasma preparation are commonly applied in clinical monitoring of angiogenesis parameters which may account for the differences in reported plasma values and may have masked their predictive or prognostic marker potential.

Summary.  Background:  Measuring platelet activation in patients has become a potent method to investigate pathophysiological processes. However, the commonly applied markers are sensitive to detrimental influences by in vitro platelet activation during blood analysis. Objectives:  Protein isoforms of platelet‐derived thrombospondin‐1 (TSP‐1) were investigated for their potential to identify in vitro platelet activation when monitoring in vivo processes. Methods:  TSP‐1 was determined in plasma, serum or supernatant of purified platelets by ELISA and immunoblotting and was compared with standard markers of platelet activation. A collective of 20 healthy individuals and 30 cancer patients was analyzed. Results:  While in vitro platelet degranulation led to a selective increase in the 200‐kDa full‐length molecule, an in vivo process involving platelet activation such as wound healing resulted in the predominant rise of the 140‐kDa TSP‐1 protein. The physiological ratio of circulating TSP‐1 variants was determined and a cut‐off level at 1.0 was defined to identify plasma samples with artificial in vitro platelet activation exceeding the cut‐off level. In contrast, cancer patients known to frequently exhibit increased in vivo activation of platelets presented with a significantly decreased ratio of TSP‐1 variants as compared with healthy volunteers. Conclusions:  In comparison to standard platelet markers, TSP‐1 constitutes a sensitive and stable parameter suited to monitor in vitro platelet activation. The analysis of TSP‐1 protein isoforms further offers a valuable tool to reliably discriminate between in vitro and in vivo effects, to exclude variability introduced during blood processing and improve clinical monitoring.

Background and Aims The Model for End‐Stage Liver Disease (MELD) is used for clinical decision‐making and organ allocation for orthotopic liver transplantation (OLT) and was previously upgraded through inclusion of serum sodium (Na) concentrations (MELD‐Na). However, MELD‐Na may underestimate complications arising from portal hypertension or infection. The von Willebrand factor (vWF) antigen (vWF‐Ag) correlates with portal pressure and seems capable of predicting complications in patients with cirrhosis. Accordingly, this study aimed to evaluate vWF‐Ag as an adjunct surrogate marker for risk stratification on the waiting list for OLT. Approach and Results Hence, WF‐Ag at time of listing was assessed in patients listed for OLT. Clinical characteristics, MELD‐Na, and mortality on the waiting list were recorded. Prediction of 3‐month waiting‐list survival was assessed by receiver operating characteristics and net reclassification improvement. Interestingly, patients dying within 3 months on the waiting list displayed elevated levels of vWF‐Ag (P < 0.001). MELD‐Na and vWF‐Ag were comparable and independent in their predictive potential for 3‐month mortality on the waiting list (area under the curve [AUC], vWF‐Ag = 0.739; MELD‐Na = 0.764). Importantly, a vWF‐Ag cutoff at 413% identified patients at risk for death within 3 months of listing with a higher odds ratio (OR) than the previously published cutoff at a MELD‐Na of 20 points (vWF‐Ag, OR = 10.873, 95% confidence interval [CI], 3.160, 36.084; MELD‐Na, OR = 7.594, 95% CI, 2.578, 22.372; P < 0.001, respectively). Ultimately, inclusion of vWF‐Ag into the MELD‐Na equation significantly improved prediction of 3‐month waiting‐list mortality (AUC, MELD‐Na–vWF = 0.804). Conclusions A single measurement of vWF‐Ag at listing for OLT predicts early mortality. Combining vWF‐Ag levels with MELD‐Na improves risk stratification and may help to prioritize organ allocation to decrease waiting‐list mortality.