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

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

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

Results: Untargeted lipidomics identified 2,013 lipids across 8 lipid-groups. 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 in ALF-NS were strongly correlated(r2>0.7, p<0.05). Multi-modular correlation network showed striking associations between lipid, Fungal-peptides modules, and Clinical parameters specific to ALF-NS (p<0.05). Cryptococcus amylolentus CBS6039 and Penicillium oxalicum1142 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 POD-lipid (AUC=0.969) and HR=1.99(1.02-2.04) superseded POD-fungus and severity indices for early-mortality prediction.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 predicted early-mortality with >95% accuracy/sensitivity/specificity using ANN and ML. Interestingly, fungal surveillance protein Clec7a was significantly downregulated (>2-fold), leading to a notable rise in fungal infection-mediated choline/phosphatidylcholine and associated enzymes (FC>1.5; Kennedy cycle). This contributed to phosphatidic acid-mediated hyper-inflammation in ALF-non-survivors.

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