Plasma lipidomics and fungal peptide-based community analysis identifies distinct signatures for early mortality in acute liver failure.

Abstract

Background/aims: Acute liver failure (ALF) has high mortality predominantly due to compromised immune system and increased vulnerability to bacterial and fungal infections.

Methods: Plasma lipidome and fungal peptide-based community (mycobiome) analysis were performed in discovery cohort (ALF=40, healthy=5) and validated in a validation cohort of 230 patients with ALF using high-resolution-mass-spectrometry, artificial neural network (ANN) and machine learning (ML).

Results: Untargeted lipidomics identified 2,013 lipids across 8 lipid group. 5 lipid-species-phosphatidylcholine (PC)[15:0/17:0], PC[20:1/14:1], PC[26:4/10:0], PC[32:0] and TG[4:0/10:0/23:6]-significantly differentiated ALF-NS (FC>10, P<0.05, FDR<0.01). Mycobiome alpha/beta diversity was significantly higher and showed 4 phyla and >20 species significantly dysregulated in ALF-NS linked with lipid metabolism, fatty acid elongation in ER, and others (P<0.05). Lipid and mycobiome diversity values in ALF-NS were strongly correlated (r2>0.7, P<0.05). Multi-modular correlation network showed striking associations between lipid, fungal peptide modules, and clinical parameters specific to ALF-NS (P<0.05). Cryptococcus amylolentus CBS6039 and Penicillium oxalicum 1142 directly correlated with phosphatidylcholine, triglycerides, and severity in ALF-NS (r2>0.85, P<0.05). POD-fungus and POD-lipids showed direct association with infection, necrosis, and hepatic encephalopathy (Beta>1.2, P<0.05). POD-lipid (AUC=0.969 and HR=1.99 [1.02-2.04]) superseded POD-fungus and severity indices for early-mortality prediction. Finally, significant increase in PC (15:0/17:0) level showed highest normalized importance, and ANNs and ML predicted early mortality with >95% accuracy, sensitivity, and specificity. Interestingly, fungal surveillance protein Clec7a was significantly downregulated (>2-fold), leading to a notable increase in fungal infection-mediated choline/phosphatidylcholine and associated enzymes (FC>1.5; Kennedy cycle). This contributed to phosphatidic acid-mediated hyper-inflammation in ALF-NS.

Conclusion: In ALF, the plasma lipidome and mycobiome are dysregulated. Increased circulating phosphatidylcholine could stratify ALF predisposed to early mortality or require emergency liver transplantation.