Bioenergetic Failure Drives Functional Exhaustion of Monocytes in Acute-on-Chronic Liver Failure.

Objective: The monocyte-macrophage system is central to the host's innate immune defense and in resolving injury. It is reported to be dysfunctional in acute-on-chronic liver failure (ACLF). The disease-associated alterations in ACLF monocytes are not fully understood. We investigated the mechanism of monocytes' functional exhaustion and the role of umbilical cord mesenchymal stem cells (ucMSCs) in re-energizing monocytes in ACLF. Design: Monocytes were isolated from the peripheral blood of ACLF patients (n = 34) and matched healthy controls (n = 7) and patients with compensated cirrhosis (n = 7); phagocytic function, oxidative burst, and bioenergetics were analyzed. In the ACLF mouse model, ucMSCs were infused intravenously, and animals were sacrificed at 24 h and day 11 to assess changes in monocyte function, liver injury, and regeneration. Results: Patients with ACLF (alcohol 64%) compared with healthy controls and those with compensated cirrhosis had an increased number of peripheral blood monocytes (p < 0.0001) which displayed significant defects in phagocytic (p < 0.0001) and oxidative burst capacity (p < 0.0001). ACLF patients also showed a significant increase in the number of liver macrophages as compared with healthy controls (p < 0.001). Bioenergetic analysis showed markedly reduced oxidative phosphorylation (p < 0.0001) and glycolysis (p < 0.001) in ACLF monocytes. Patients with monocytes having maximum mitochondrial respiration of <37.9 pmol/min [AUC = 0.822, hazard ratio (HR) = 4.5] and baseline glycolysis of ≤42.7 mpH/min (AUC = 0.901, HR = 9.1) showed increased 28-day mortality (p < 0.001). Co-culturing ACLF monocytes with ucMSC showed improved mitochondrial respiration (p < 0.01) and phagocytosis (p < 0.0001). Furthermore, ucMSC therapy increased monocyte energy (p < 0.01) and phagocytosis (p < 0.001), reduced hepatic injury, and enhanced hepatocyte regeneration in ACLF animals. Conclusion: Bioenergetic failure drives the functional exhaustion of monocytes in ACLF. ucMSCs resuscitate monocyte energy and prevent its exhaustion. Restoring monocyte function can ameliorate hepatic injury and promote liver regeneration in the animal model of ACLF.

Omega-3 fatty acid lipid emulsions are safe and effective in reducing endotoxemia and sepsis in acute-on-chronic liver failure: An open-label randomized controlled trial.

BACKGROUND AND AIM: Sepsis is an important determinant of the outcome of acute-on-chronic liver failure (ACLF) patients. Omega-3 fatty acids (FAs) are known to suppress inflammation, reduce morbidity, and mortality in postoperative and critically ill patients. We aimed to evaluate the effect of intravenous omega-6 and omega-3 FA lipid emulsions in ACLF patients. METHODS: Ninety ACLF patients were randomly allocated to three groups: Gr. A received no lipid emulsions, Gr. B received omega-6 FAs, and Gr. C received omega-3 FAs. The primary and secondary aims were to compare the effects of lipid emulsions on immune modulation, the incidence of bacterial sepsis, and mortality at day 28. RESULTS: The baseline characteristics of the patients were comparable. Serum endotoxin levels remained suppressed by 22% in Gr. C compared with a 4% and 12% rise in Gr. B and A (P < 0.001). Omega-3 FAs also suppressed C-reactive protein levels and neutrophil-to-lymphocyte ratio in Gr. C. Compared with Gr. A, omega-3 FAs reduced sepsis by 86% (HR, 0.14; 95% CI 0.04-0.43; P < 0.001). Omega-3 FAs significantly increased the expression of TLR2 and TLR4 on both CD14+ and CD16+ monocytes, and TLR4, on macrophages and neutrophils. There were no serious adverse events, except transient flushing in 20% and 16.6% of patients receiving omega-6 FAs and omega-3 FAs, respectively. CONCLUSION: Omega-3 FAs are safe and effective in reducing systemic inflammation, endotoxemia, and sepsis in patients with ACLF. These lipid emulsions could also be considered as effective sources of immunonutrition in such sick patients.