Abstract
BACKGROUND AND AIMS: Acute-on-chronic liver failure (ACLF) is associated with excessive systemic inflammation, cell death, and organ failures. Yet, little is known about the hepatic histopathology of ACLF. Here, we assessed the histopathology and regenerative capacity of the liver in ACLF with or without cirrhosis. METHODS: Liver specimens of patients with compensated cirrhosis (N = 37), acute decompensation (N = 40), and ACLF with (N = 18) or without (N = 10) cirrhosis were assessed for morphological features and the pro-regenerative Stat3 pathway. RESULTS: ACLF was associated with high levels of lobular inflammation, tissue necrosis, and apoptosis. In patients with cirrhosis, the percentage of pStat3-positive hepatocytes was increasing with disease severity (3.5%/10.4%/21% for compensated cirrhosis/acute decompensation/cirrhosis-ACLF; P < .001), but lower in noncirrhotic ACLF vs cirrhosis-ACLF (21% vs 13%; P = .02). A distinct pattern of the expression of the proliferation marker Ki-67, a downstream effector marker of pStat3, was observed. Ki-67-positive hepatocytes were more frequent in patients with cirrhosis-ACLF compared to compensated cirrhosis or acute decompensation (4.9% vs 1.3% vs 1.8%; P < .05), but much lower in cirrhosis-ACLF vs noncirrhotic ACLF (4.9% vs 13.5%; P = .01). The ratio of Ki-67-positive to pStat3-positive hepatocytes was lowest in cirrhosis-ACLF and predicted 3-month transplant-free survival accurately (area under the curve = 0.95, P < .00001). CONCLUSION: Our study identifies hepatic inflammation and Stat3 activation as hallmarks of ACLF. In cirrhosis-ACLF, Stat3 activation does not appear to translate in effective liver regeneration, which is distinct from noncirrhotic ACLF.