The von Willebrand Factor Facilitates Model for End-Stage Liver Disease-Independent Risk Stratification on the Waiting List for Liver Transplantation

Von Willebrand factor for outcome prediction within different clinical stages of advanced chronic liver disease

BACKGROUND AND AIMS

The prognostic performance of von Willebrand factor (VWF) may vary across clinical stages of advanced chronic liver disease (ACLD). Therefore, we investigated the evolution of VWF and other biomarkers throughout the full ACLD spectrum and evaluated their stage-specific prognostic utility.

METHODS

We retrospectively included Viennese ACLD patients with available information on hepatic venous pressure gradient (HVPG), C-reactive protein (CRP)/VWF levels and outcomes. ACLD stages were defined according to D'Amico et al. We included an external validation cohort from Padua.

RESULTS

We observed gradual increases in VWF throughout ACLD stages. In contrast, HVPG levelled off in decompensated ACLD (dACLD), whereas MELD showed only minor changes in the early stages and CRP did not increase until stage 3. VWF was associated with hepatic decompensation/liver-related death in compensated ACLD (cACLD) in a fully adjusted model, while it was not independently predictive of ACLF/liver-related death in dACLD. After backward selection, HVPG/CRP/VWF remained the main predictors of hepatic decompensation/liver-related death in cACLD. Notably, the performance of the non-invasive CRP/VWF-based model was comparable to invasive HVPG-based models (C-index:0.765 ± 0.034 vs. 0.756 ± 0.040). The discriminative ability of the CRP/VWF-based model was confirmed in an external validation cohort using another VWF assay which yielded systematically lower values.

CONCLUSION

VWF is the only biomarker that gradually increases across all ACLD stages. It is of particular prognostic value in cACLD, where a CRP/VWF-based model is equivalent to an invasive HVPG-based model. Systematic differences in VWF underline the importance of interlaboratory surveys. Moreover, our findings reinforce the notion that, already in cACLD, inflammation is a key disease-driving mechanism.

Serum/Plasma Proteome in Non-Malignant Liver Disease

The liver is the central metabolic organ and produces 85-90% of the proteins found in plasma. Accordingly, the plasma proteome is an attractive source of liver disease biomarkers that reflects the different cell types present in this organ, as well as the processes such as responses to acute and chronic injury or the formation of an extracellular matrix. In the first part, we summarize the biomarkers routinely used in clinical evaluations and their biological relevance in the different stages of non-malignant liver disease. Later, we describe the current proteomic approaches, including mass spectrometry and affinity-based techniques, that allow a more comprehensive assessment of the liver function but also require complex data processing. The many approaches of analysis and interpretation and their potential caveats are delineated. While these advances hold the promise to transform our understanding of liver diseases and support the development and validation of new liver-related drugs, an interdisciplinary collaboration is needed.

MELD-Na score may underestimate disease severity and risk of death in patients with metabolic dysfunction-associated steatotic liver disease (MASLD)

Portal hypertension often precedes the development of advanced fibrosis in patients with Metabolic dysfunction-associated steatotic liver disease (MASLD) and may accelerate disease progression to cirrhosis. We aimed to evaluate whether prioritization tools accurately predict survival in patients with MASLD and clinically significant portal hypertension (CSPH). We retrospectively identified patients diagnosed with esophageal or gastric varices (EGV). Laboratory results, endoscopy reports and outcomes of patients with MASLD were compared to patients with advanced stage chronic liver disease (CLD) of other etiologies. During the study period 326 patients were diagnosed with EGV. 88 (26.9%) had MASLD, 113 (34.6%) viral hepatitis (VH), 63 (19.3%) alcoholic liver disease (ALD) and 62 (19%) both VH and ALD (VHALD). EGV bleeding events were significantly more frequent in patients with MASLD (36.3%), compared to VH (28.3%), ALD (30.1%) and VHALD (25.8%), respectively (p < 0.01). Mean Model for End-Stage Liver Disease (MELD)-Na score surrounding 1 year of first event of EGV bleeding was significantly lower in MASLD patients compared to all other etiologies (p = 0.02). At a MELD-Na score of 11-20, cumulative survival rate was significantly lower in MASLD patients compared to all other etiologies (log rank p < 0.01). MASLD patients present with EGV bleeding at lower MELD-Na scores compared to other etiologies of CLD. MELD-Na score may therefore underestimate disease severity and risk of death in patients with MASLD and CSPH.

Novel prognostic biomarkers in decompensated cirrhosis: a systematic review and meta-analysis

BACKGROUND

Patients with decompensated cirrhosis experience high mortality rates. Current prognostic scores, including the model for end-stage liver disease (MELD), may underperform in settings other than in those they were initially developed. Novel biomarkers have been proposed to improve prognostication accuracy and even to predict development of complications.

METHODS

We performed a systematic review and meta-analysis on novel urine and blood biomarkers and their ability to predict 90-day mortality in patients with decompensated cirrhosis. Secondary outcomes included 28-day and 1-year mortality, and development of acute-on-chronic liver failure, acute kidney injury and other complications. To overcome differences in units, temporal changes in assays and reporting heterogeneity, we used the ratio of means (RoM) as measure of association for assessing strength in predicting outcomes. An RoM>1 implies that the mean biomarker level is higher in those that develop the outcome than in those that do not.

RESULTS

Of 6629 unique references, 103 were included, reporting on 29 different biomarkers, with a total of 31 362 biomarker patients. Most studies were prospective cohorts of hospitalised patients (median Child-Pugh-Turcotte score of 9 and MELD score of 18). The pooled 90-day mortality rate was 0.27 (95% CI 0.24 to 0.29). The RoM for predicting 90-day mortality was highest for interleukin 6 (IL-6) (2.56, 95% CI 2.39 to 2.74), followed by urinary neutrophil gelatinase-associated lipocalin (uNGAL) (2.42, 95% CI 2.20 to 2.66) and copeptin (2.33, 95% CI 2.17 to 2.50). These RoMs were all higher than for MELD (1.44, 95% CI 1.42 to 1.46).

CONCLUSION

Novel biomarkers, including IL-6, uNGAL and copeptin, can probably improve prognostication of patients with decompensated cirrhosis compared with MELD alone.

Von Willebrand factor is an independent predictor of short-term mortality in acutely ill patients with cirrhosis

BACKGROUND AND AIMS

Levels of von Willebrand factor (VWF) are elevated in patients with cirrhosis, and correlate well with disease severity. In patients with decompensated cirrhosis (DC), plasma VWF is associated with mortality. The value of VWF in predicting short-term mortality risk in patients with acute-on-chronic liver failure (ACLF) is, however, unclear.

METHODS

We included patients with DC (n = 111) and ACLF (n = 105). We measured VWF levels and correlated these with other laboratory parameters and prediction models for mortality. Also, we assessed the predictive value of VWF in the prediction of 90- and 30-day mortality in patients with DC and ACLF, respectively, and compared this to the predictive value of clinically used prediction models. Finally, we determined the optimal cut-off value for VWF in patients with ACLF.

RESULTS

Sixteen of 111 (14%) patients with DC and 35 of 105 (33%) with ACLF died within 90 and 30 days, respectively. VWF was associated with mortality and correlated closely with other prediction models. In patients with ACLF, VWF levels had a discrimination for 30-day mortality comparable with these models and accurately identified ACLF patients with high 30-day mortality risk.

CONCLUSIONS

Levels of VWF associate closely with risk of mortality in patients with DC and ACLF, and may have predictive utility as a laboratory marker of prognosis. Further research is warranted to assess the additional value of VWF in the prediction of mortality and associated complications in chronic liver failure syndromes.

Von Willebrand Factor as a Biomarker for Liver Disease - An Update

The von Willebrand factor (vWF) is best known for its role in the hemostatic pathway, aiding platelet adhesion and aggregation, as well as circulating along with coagulation factor VIII, prolonging its half-life. However, vWF is more than a hemostatic protein and is a marker of endothelial dysfunction in patients with cirrhosis. The levels of vWF increase progressively as cirrhosis progresses. Despite its qualitative defects, it can support and carry out its hemostatic role and contribute to a pro-coagulant disbalance. Moreover, it has been shown to be a good noninvasive marker for predicting clinically significant portal hypertension (CSPH). The vWF has been shown to predict decompensation and mortality among cirrhosis patients independently of the stage of liver disease and severity of portal hypertension. Increased vWF levels in the setting of endothelial injury predict bacterial translocation and systemic inflammation. The vWF-to-thrombocyte ratio (VITRO) score adds to the diagnostic ability of vWF alone in detecting CSPH non-invasively. Not only have vWF levels been shown to help predict the risk of hepatocellular carcinoma (HCC) among cirrhosis patients, but they also predict the risk of complications post-resection for HCC and response to systemic therapies. vWF-induced portal microthrombi have been purported to contribute to the pathogenesis of acute liver failure progression as well as non-cirrhotic portal hypertension. The prospect of modulation of vWF levels using drugs such as non-selective beta-blockers, statins, anticoagulants, and non-absorbable antibiotics and its use as a predictive biomarker for the response to these drugs needs to be explored.

Integration of deep learning-based histopathology and transcriptomics reveals key genes associated with fibrogenesis in patients with advanced NASH

Nonalcoholic steatohepatitis (NASH) is the most common chronic liver disease globally and a leading cause for liver transplantation in the US. Its pathogenesis remains imprecisely defined. We combined two high-resolution modalities to tissue samples from NASH clinical trials, machine learning (ML)-based quantification of histological features and transcriptomics, to identify genes that are associated with disease progression and clinical events. A histopathology-driven 5-gene expression signature predicted disease progression and clinical events in patients with NASH with F3 (pre-cirrhotic) and F4 (cirrhotic) fibrosis. Notably, the Notch signaling pathway and genes implicated in liver-related diseases were enriched in this expression signature. In a validation cohort where pharmacologic intervention improved disease histology, multiple Notch signaling components were suppressed.

Assessment of portal hypertension severity using machine learning models in patients with compensated cirrhosis

BACKGROUND & AIMS

In individuals with compensated advanced chronic liver disease (cACLD), the severity of portal hypertension (PH) determines the risk of decompensation. Invasive measurement of the hepatic venous pressure gradient (HVPG) is the diagnostic gold standard for PH. We evaluated the utility of machine learning models (MLMs) based on standard laboratory parameters to predict the severity of PH in individuals with cACLD.

METHODS

A detailed laboratory workup of individuals with cACLD recruited from the Vienna cohort (NCT03267615) was utilised to predict clinically significant portal hypertension (CSPH, i.e., HVPG ≥10 mmHg) and severe PH (i.e., HVPG ≥16 mmHg). The MLMs were then evaluated in individual external datasets and optimised in the merged cohort.

RESULTS

Among 1,232 participants with cACLD, the prevalence of CSPH/severe PH was similar in the Vienna (n = 163, 67.4%/35.0%) and validation (n = 1,069, 70.3%/34.7%) cohorts. The MLMs were based on 3 (3P: platelet count, bilirubin, international normalised ratio) or 5 (5P: +cholinesterase, +gamma-glutamyl transferase, +activated partial thromboplastin time replacing international normalised ratio) laboratory parameters. The MLMs performed robustly in the Vienna cohort. 5P-MLM had the best AUCs for CSPH (0.813) and severe PH (0.887) and compared favourably to liver stiffness measurement (AUC: 0.808). Their performance in external validation datasets was heterogeneous (AUCs: 0.589-0.887). Training on the merged cohort optimised model performance for CSPH (AUCs for 3P and 5P: 0.775 and 0.789, respectively) and severe PH (0.737 and 0.828, respectively).

CONCLUSIONS

Internally trained MLMs reliably predicted PH severity in the Vienna cACLD cohort but exhibited heterogeneous results on external validation. The proposed 3P/5P online tool can reliably identify individuals with CSPH or severe PH, who are thus at risk of hepatic decompensation.

IMPACT AND IMPLICATIONS

We used machine learning models based on widely available laboratory parameters to develop a non-invasive model to predict the severity of portal hypertension in individuals with compensated cirrhosis, who currently require invasive measurement of hepatic venous pressure gradient. We validated our findings in a large multicentre cohort of individuals with advanced chronic liver disease (cACLD) of any cause. Finally, we provide a readily available online calculator, based on 3 (platelet count, bilirubin, international normalised ratio) or 5 (platelet count, bilirubin, activated partial thromboplastin time, gamma-glutamyltransferase, choline-esterase) widely available laboratory parameters, that clinicians can use to predict the likelihood of their patients with cACLD having clinically significant or severe portal hypertension.

The systemic and hepatic alternative renin-angiotensin system is activated in liver cirrhosis, linked to endothelial dysfunction and inflammation

We aimed to assess the systemic and hepatic renin-angiotensin-system (RAS) fingerprint in advanced chronic liver disease (ACLD). This prospective study included 13 compensated (cACLD) and 12 decompensated ACLD (dACLD) patients undergoing hepatic venous pressure gradient (HVPG) measurement. Plasma components (all patients) and liver-local enzymes (n = 5) of the RAS were analyzed using liquid chromatography-tandem mass spectrometry. Patients with dACLD had significantly higher angiotensin (Ang) I, Ang II and aldosterone plasma levels. Ang 1-7, a major mediator of the alternative RAS, was almost exclusively detectable in dACLD (n = 12/13; vs. n = 1/13 in cACLD). Also, dACLD patients had higher Ang 1-5 (33.5 pmol/L versus cACLD: 6.6 pmol/L, p < 0.001) and numerically higher Ang III and Ang IV levels. Ang 1-7 correlated with HVPG (ρ = 0.655; p < 0.001), von Willebrand Factor (ρ = 0.681; p < 0.001), MELD (ρ = 0.593; p = 0.002) and interleukin-6 (ρ = 0.418; p = 0.047). Considerable activity of ACE, chymase, ACE2, and neprilysin was detectable in all liver biopsies, with highest chymase and ACE2 activity in cACLD patients. While liver-local classical and alternative RAS activity was already observed in cACLD, systemic activation of alternative RAS components occurred only in dACLD. Increased Ang 1-7 was linked to severe liver disease, portal hypertension, endothelial dysfunction and inflammation.

Portal vein thrombosis compromises the performance of MELD and MELD-Na scores in patients with cirrhosis

BACKGROUND AND AIMS

The accuracy of model for end-stage liver disease (MELD) and MELD with sodium (MELD-Na) scores in reflecting the clinical outcomes of patients with cirrhosis and portal vein thrombosis (PVT) remains unclear. This study aimed to evaluate the performance of scores in predicting 90-day mortality in patients with cirrhosis and PVT.

METHODS

Post hoc analysis was performed in two prospective cohorts (NCT02457637 and NCT03641872). The correlation between the MELD/MELD-Na score and 90-day liver transplantation (LT)-free mortality was investigated in patients with cirrhosis with and without PVT.

RESULTS

In this study, 2826 patients with cirrhosis were included, and 255 (9.02%) had PVT. The cumulative incidence of 90-day LT-free mortality did not significantly differ between patients with and without PVT (log-rank P = 0.0854). MELD [area under the receiver operating curve (AUROC), 0.649 vs. 0.842; P = 0.0036] and MELD-Na scores (AUROC, 0.691 vs. 0.851; P = 0.0108) were compared in patients with and without PVT, regarding the prediction of 90-day LT-free mortality. In MELD < 15 and MELD-Na < 20 subgroups, patients with PVT had a higher 90-day LT-free mortality than those without PVT (7.91% vs. 2.64%, log-rank P = 0.0011; 7.14% vs. 3.43%, log-rank P = 0.0223), whereas in MELD ≥ 15 and MELD-Na ≥ 20 subgroups, no significant difference was observed between patients with and without PVT.

CONCLUSIONS

The performance of MELD and MELD-Na scores in predicting 90-day LT-free mortality of patients with cirrhosis was compromised by PVT. MELD < 15 or MELD-Na < 20 may underestimate the 90-day LT-free mortality in patients with PVT.

Clinical significance of substantially elevated von Willebrand factor antigen levels in patients with advanced chronic liver disease

BACKGROUND

Von Willebrand factor antigen (VWF) is a non-invasive marker for clinically significant portal hypertension (HVPG≥10 mmHg) and confers HVPG-independent prognostic information. While quantification of increased VWF-levels is not relevant in the context of von Willebrand disease, highly elevated VWF may be of clinical significance in ACLD. Thus, we have modified our analytical approach to quantify very high VWF-levels (i.e.,>420%) and investigated their prognostic value.

METHODS

Patients undergoing HVPG-measurement at the Vienna Hepatic Hemodynamic Lab with evidence of ACLD and information on VWF were considered. Clinical stages (CS) were defined as follows: Probable compensated ACLD (cACLD): LSM≥10kPa&HVPG<6 mmHg; 0: cACLD&6-9 mmHg; 1: cACLD&HVPG≥10 mmHg; 2: bleeding; 3: non-bleeding decompensation; 4: ≥2 decompensations.

RESULTS

124 (16%) of 793 patients had VWF>420%. The proportion of VWF>420% increased with disease severity (probable cACLD-0: 5(4%) vs. 1: 22(10%) vs. 2-4: 97(23%),p ≤ 0.001) as well as across HVPG (<6mmHg: 1(2%) vs. 6-9: 6(6%) vs. 10-15: 17(9%) vs. ≥16: 100(22%),p ≤ 0.001) and MELD (<10: 17(6%) vs. 10-14: 27(10%) vs. ≥15: 79(32%),p ≤ 0.001) strata. In patients with VWF>420%, median VWF was 533 (IQR:466-611)% and VWF was unrelated to HVPG (Spearman's ρ=0.139,p = 0.123), but showed direct correlations of weak/moderate strength with MELD (ρ=0.336,p < 0.001) and CRP (ρ=0.286,p = 0.001). In the subgroup with VWF>420%, VWF was predictive of decompensation/liver-related mortality (VWF per 10%; hazard ratio (HR): 1.02(95% confidence interval (95%CI): 1.01-1.04),p = 0.008, even after adjusting for other factors (VWF per 10%; adjusted HR: 1.02(95%CI: 1.00-1.05),p = 0.031).

CONCLUSION

The proportion of patients with substantially elevated VWF values steadily increases with disease progression. While VWF is not reflective of HVPG in these patients, it is correlated with hepatic dysfunction and systemic inflammation. Importantly, quantification of high values provides prognostic information.

Serum 25-hydroxyvitamin D and C-reactive protein and plasma von Willebrand concentrations in 23 dogs with chronic hepatopathies

BACKGROUND

Serum concentrations of 25-hydroxyvitamin D (25(OH)VD) and C-reactive protein (CRP) and von Willebrand's factor (vWF) concentration correlate with histopathologic disease grade and stage in chronic inflammatory and fibrotic hepatopathies (CH) in humans.

OBJECTIVES

To evaluate serum 25(OH)VD and serum CRP concentrations and plasma vWF concentration and determine if they correlate with histopathologic and biochemical variables in dog with CH.

ANIMALS

Twenty-three client-owned dogs with a histopathologic diagnosis of CH were prospectively enrolled.

METHODS

Blood samples were collected before liver biopsy. Correlations between biomarkers and clinical pathological and histopathologic variables were evaluated using Pearson's or Spearman's test.

RESULTS

Serum 25(OH)VD concentration (median, 213 nmol/L; range, 42-527 nmol/L) was negatively correlated with serum aspartate aminotransferase activity (AST; rho = -0.59, P < .01), polymorphonuclear neutrophil count (PMN; r = -0.46, P < .05), and positively correlated with serum albumin concentration (r = 0.69, P < .001). Serum CRP concentration (median, 7.4 μg/L; range, 1-44.9 μg/L) was positively correlated with overall histopathologic necroinflammatory activity (r = 0.78, P < .001) and fibrosis score (rho = 0.49, P < .05). Plasma vWF concentration (median, 73.3%; range, 15-141%) was positively correlated with fibrosis score (r = 0.53, P < .05) and prothrombin time (rho = 0.67, P < .01), and negatively correlated with serum albumin concentration (r = -0.73, P < .001).

CONCLUSION AND CLINICAL IMPORTANCE

In dogs with CH, serum 25(OH)VD concentration was negatively correlated with disease activity, whereas serum CRP concentration and plasma vWF concentration were positively correlated with histopathologic grade and stage. Our results provide preliminary evidence that these biomarkers may be useful to assess grade and stage of CH in dogs in the absence of liver biopsy.

Factor VIII/protein C ratio independently predicts liver-related events but does not indicate a hypercoagulable state in ACLD

BACKGROUND & AIMS

It has been suggested that the ratio of procoagulant factor VIII to anticoagulant protein C (FVIII/PC) reflects the hemostatic equilibrium. Moreover, FVIII/PC predicted decompensation/death in a small study not accounting for portal hypertension severity. We investigated (i) the prognostic value of FVIII/PC (outcome-cohort) and (ii) whether FVIII/PC reflects the hypercoagulable state (assessed by thrombomodulin-modified thrombin generation assay [TM-TGA]) or the risk of bleeding/thrombotic events in patients undergoing hepatic venous pressure gradient (HVPG) measurement during follow-up.

METHODS

(i) The outcome-cohort comprised 576 patients with evidence of advanced chronic liver disease (liver stiffness measurement ≥10 kPa and/or HVPG ≥6 mmHg). (ii) TM-TGA-cohort patients (n = 142) were recruited from the prospective VIenna CIrrhosis Study (VICIS: NCT03267615).

RESULTS

(i) FVIII/PC significantly increased across clinical stages (p <0.001) as well as HVPG (p <0.001) and MELD score (p <0.001) strata and remained independently associated with decompensation/liver-related death (adjusted hazard ratio 1.06; 95% CI 1.01-1.11; p = 0.013), even after multivariable adjustment. It was also associated with acute-on-chronic liver failure (ACLF) development (adjusted hazard ratio 1.10; 95% CI 1.02-1.19; p = 0.015) in patients with decompensated cirrhosis. (ii) FVIII/PC showed a weak positive correlation with endogenous thrombin potential (Spearman's ρ = 0.255; p = 0.002), but this association disappeared after adjusting for the severity of liver disease. FVIII/PC was not associated with the development of bleeding (p = 0.272) or thrombotic events (p = 0.269). However, FVIII/PC correlated with biomarkers of different pathophysiological mechanisms that promote liver disease progression.

CONCLUSION

FVIII/PC provides prognostic information regarding hepatic decompensation/death and ACLF, independently of established prognostic indicators. However, this is not evidence that hypercoagulability drives disease progression, as the correlation between FVIII/PC and thrombin generation is confounded by liver disease severity and FVIII/PC was not associated with thrombosis. Therefore, FVIII/PC does not reflect coagulation and results from previous studies on FVIII/PC require re-interpretation.

CLINICAL TRIAL NUMBER

NCT03267615 (in part).

LAY SUMMARY

A balanced coagulation system is essential for preventing bleeding episodes and blood clot formation (thrombosis). Blood of patients with advanced liver disease may have increased coagulation potential, possibly promoting the worsening of liver disease via thrombosis in the blood vessels of the liver. The ratio between the results of 2 blood tests (procoagulant factor VIII to anticoagulant protein C) has been suggested to reflect these increases in coagulation potential. Our study demonstrates, on the one hand, that this ratio is a versatile predictor of the development of complications of cirrhosis, yet on the other hand, that it is unrelated to coagulation.

Recognizing Dysfunctional Innate and Adaptive Immune Responses Contributing to Liver Damage in Patients With Cirrhosis

The human host immune system wards off attacks by enemies such as viruses by mounting an inflammatory response which may sometimes injure self-tissues. Dysfunctional immune/inflammatory response by the host may affect the functioning of vital organs. The largest number of innate immune cells in the body resides in the liver. On encountering a new insult or injury to the liver, the innate immune system responds quickly to counter it. Acute liver insults may trigger acute liver failure or acute on chronic liver failure; these disorders are associated with a predominant innate immune response. Activation of the reticuloendothelial system (part of the innate immune response) predicts short-term and medium-term survival in patients with acute on chronic liver failure. Liver diseases associated with an aberrant adaptive immune response like autoimmune hepatitis respond well to treatment with steroids and other immunosuppressants, while those associated with innate immune dysfunction like acute on chronic liver failure do not respond well to steroids; recent reports suggest that the latter disorders may respond to therapeutic plasma exchange. How does the immune system in a patient with liver disease respond to SARS CoV2 infection? While commonly used tests in routine clinical practice provide clues to activation of different arms of immune response in patients with cirrhosis, specialized tests may help characterize this further. This review discusses the tests which reflect aberrant immune responses and treatment of patients with cirrhosis.

The Addition of C-Reactive Protein and von Willebrand Factor to Model for End-Stage Liver Disease-Sodium Improves Prediction of Waitlist Mortality

BACKGROUND AND AIMS

Patients with cirrhosis on the liver transplant (LT) waiting list may die or be removed because of complications of portal hypertension (PH) or infections. von Willebrand factor antigen (vWF-Ag) and C-reactive protein (CRP) are simple, broadly available markers of these processes.

APPROACH AND RESULTS

We determined whether addition of vWF-Ag and CRP to the Model for End-Stage Liver Disease-Sodium (MELD-Na) score improves risk stratification of patients awaiting LT. CRP and vWF-Ag at LT listing were assessed in two independent cohorts (Medical University of Vienna [exploration cohort] and Mayo Clinic Rochester [validation cohort]). Clinical characteristics, MELD-Na, and mortality on the waiting list were recorded. Prediction of 3-month waiting list mortality was assessed by receiver operating characteristics curve (ROC-AUC). In order to explore potential mechanisms underlying the prognostic utility of vWF-Ag and CRP in this setting, we evaluated their association with PH, bacterial translocation, systemic inflammation, and circulatory dysfunction. In the exploration cohort (n = 269) vWF-Ag and CRP both improved the predictive value of MELD-Na for 3-month waitlist mortality and showed the highest predictive value when combined (AUC: MELD-Na, 0.764; MELD-Na + CRP, 0.790; MELD-Na + vWF, 0.803; MELD-Na + CRP + vWF-Ag, 0.824). Results were confirmed in an independent validation cohort (n = 129; AUC: MELD-Na, 0.677; MELD-Na + CRP + vWF-Ag, 0.882). vWF-Ag was independently associated with PH and inflammatory biomarkers, whereas CRP closely, and MELD independently, correlated with biomarkers of bacterial translocation/inflammation.

CONCLUSIONS

The addition of vWF-Ag and CRP-reflecting central pathophysiological mechanisms of PH, bacterial translocation, and inflammation, that are all drivers of mortality on the waiting list for LT-to the MELD-Na score improves prediction of waitlist mortality. Using the vWFAg-CRP-MELD-Na model for prioritizing organ allocation may improve prediction of waitlist mortality and decrease waitlist mortality.

VWF/ADAMTS13 Imbalance, But Not Global Coagulation or Fibrinolysis, Is Associated With Outcome and Bleeding in Acute Liver Failure

BACKGROUND AND AIMS

Recent studies of acute liver failure (ALF) in man and animals have suggested that rebalanced hemostasis occurs, with distinct hypercoagulable features clinically evidenced by a low risk of bleeding. Rodent models have shown a link between intrahepatic microthrombus formation and progression of ALF. We sought to confirm these earlier findings in a large series of patients with well-characterized ALF from the Acute Liver Failure Study Group.

APPROACH AND RESULTS

Citrated plasma samples taken on admission from 676 patients with ALF or acute liver injury (international normalized ratio ≥2.0 without hepatic encephalopathy) were used to determine levels of von Willebrand factor (VWF), a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) activity, thrombomodulin-modified thrombin generation, and clot lysis time (CLT) and compared with the levels in 40 healthy controls. Patients had 3-fold increased VWF levels, 4-fold decreased ADAMTS13 activity, similar thrombin generating capacity, and 2.4-fold increased CLT, compared with controls. Increasing disease severity was associated with progressively more elevated VWF levels as well as hypofibrinolysis. Patients who died or underwent liver transplantation within 21 days of admission had higher VWF levels, lower ADAMTS13 activity, but similar thrombin generation and a similar proportion of patients with severe hypofibrinolysis, when compared with transplant-free survivors. Likewise, patients with bleeding complications had higher VWF levels and lower ADAMTS13 activity compared to those without bleeding. Thrombin generation and CLT did not differ significantly between bleeding and nonbleeding patients.

CONCLUSIONS

Rebalanced hemostatic status was confirmed in a large cohort of patients with acute liver injury/ALF, demonstrating that VWF/ADAMTS13 imbalance is associated with poor outcome and bleeding. The association between VWF/ADAMTS13 imbalance and bleeding suggests that bleeding in ALF relates more to systemic inflammation than a primary coagulopathy.

Von Willebrand Factor, Factor VIII, and Other Acute Phase Reactants as Biomarkers of Inflammation and Endothelial Dysfunction in Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGvHD) is an immune mediated late complication of allogeneic hematopoietic stem cell transplantation (alloHSCT). Discovery of adequate biomarkers could identify high-risk patients and provide an effective pre-emptive intervention or early modification of therapeutic strategy, thus reducing prevalence and severity of the disease among long-term survivors of alloHSCT. Inflammation, endothelial injury, and endothelial dysfunction are involved in cGvHD development. Altered levels of acute phase reactants have shown a strong correlation with the activity of several immune mediated disorders and are routinely used in clinical practice. Since elevated von Willebrand factor (VWF) and factor VIII (FVIII) levels have been described as acute phase reactants that may indicate endothelial dysfunction and inflammation in different settings, including chronic autoimmune diseases, they could serve as potential candidate biomarkers of cGvHD. In this review we focused on reported data regarding VWF and FVIII as well as other markers of inflammation and endothelial dysfunction, evaluating their potential role in cGvHD.

Amnion-Derived Mesenchymal Stromal/Stem Cell Paracrine Signals Potentiate Human Liver Organoid Differentiation: Translational Implications for Liver Regeneration

The prevalence of end-stage liver diseases has reached very high levels globally. The election treatment for affected patients is orthotopic liver transplantation, which is a very complex procedure, and due to the limited number of suitable organ donors, considerable research is being done on alternative therapeutic options. For instance, the use of cell therapy, such as the transplantation of hepatocytes to promote liver repair/regeneration, has been explored, but standardized protocols to produce suitable human hepatocytes are still limited. On the other hand, liver progenitor and multipotent stem cells offer potential cell sources that could be used clinically. Different studies have reported regarding the therapeutic effects of transplanted mesenchymal stromal/stem cells (MSCs) on end-stage liver diseases. Moreover, it has been shown that delivery of MSC-derived conditioned medium (MSC-CM) can reduce cell death and enhance liver proliferation in fulminant hepatic failure. Therefore, it is believed that MSC-CM contains many factors that probably support liver regeneration. In our work, we used an in vitro model of human liver organoids to study if the paracrine components secreted by human amnion-derived MSCs (hAMSCs) affected liver stem/progenitor cell differentiation. In particular, we differentiated liver organoids derived from bipotent EpCAM⁺ human liver cells and tested the effects of hAMSC secretome, derived from both two-dimensional (2D) and three-dimensional (3D) hAMSC cultures, on that model. Our analysis showed that conditioned medium (CM) produced by 3D hAMSCs was able to induce an over-expression of mature hepatocyte markers, such as ALB, NTCP, and CYP3A4, compared with both 2D hAMSC cultures and the conventional differentiation medium (DM). These data were confirmed by the over-production of ALB protein and over-activity of CYP3A4 observed in organoids grown in 3D hAMSC-CM. Liver repair dysfunction plays a role in the development of liver diseases, and effective repair likely requires the normal functioning of liver stem/progenitor cells. Herein, we showed that hAMSC-CM produced mainly by 3D cultures had the potential to increase hepatic stem/progenitor cell differentiation, demonstrating that soluble factors secreted by those cells are potentially responsible for the reaction. This work shows a potential approach to improve liver repair/regeneration also in a transplantation setting.

Noninvasive Diagnostics for Portal Hypertension: A Comprehensive Review

Noninvasive diagnostics for portal hypertension include imaging and functional tests, as well as blood-based biomarkers, and capture different features of the portal hypertensive syndrome. Definitive conclusions regarding their clinical utility require assessment of their diagnostic value in specific clinical settings (i.e., diagnosing a particular hemodynamic condition within a well-defined target population). Several noninvasive methods are predictive of clinically significant portal hypertension (CSPH; hepatic venous pressure gradient [HVPG] ≥ 10 mm Hg; the threshold for complications of portal hypertension); however, only a minority of them have been evaluated in compensated advanced chronic liver disease (i.e., the target population). Importantly, most methods correlate only weakly with HVPG at high values (i.e., in patients with CSPH). Nevertheless, selected methods show promise for diagnosing HVPG ≥ 16 mm Hg (the cut-off for increased risks of hepatic decompensation and mortality) and monitoring HVPG changes in response to nonselective beta-blockers or etiological treatments. Finally, we review established and potential future clinical applications of noninvasive methods.