Reticuloendothelial activation and phenotypic alteration of peripheral monocytes with enhanced liver recruitment drive liver injury secondary to yellow phosphorus.

BACKGROUND AND AIM: Monocytes and macrophages play a crucial role in the pathogenesis of acute liver failure (ALF). We aimed to study reticuloendothelial activation and its correlation with disease severity in commonly encountered yellow phosphorus (rodenticide)-induced hepatotoxicity patients. We also studied peripheral monocyte phenotype in a subset of patients. METHODS: Reticuloendothelial activation markers were analyzed and correlated with disease severity score in a prospectively collected database of yellow phosphorus-related hepatoxicity patients between 2018 and 2021. In a prospective cohort of these patients and age-matched healthy controls, peripheral blood monocyte phenotyping was performed. RESULTS: Reticuloendothelial activation markers were analyzed in 67 patients [Age: 23(12-64) years; median (range), men: 25, acute liver injury (ALI): 38, ALF: 29, model for end-stage liver disease (MELD) score: 28 (7-40)] of yellow phosphorus-induced hepatotoxicity. Serum ferritin (927; 10.3-34 807 ng/mL), sCD163 (4.59; 0.11-12.7 µg/mL), sCD25 (3050; 5.6-17 300 pg/mL) and plasma von Willebrand factor (423.5, 103-1106 IU/dL) were increased and showed significant correlation with liver disease severity assessed by MELD score (ρ = 0.29, ρ = 0.6, ρ = 0.56 and ρ = 0.46 respectively). Phenotyping and serum immune markers were performed in seven patients (M: 4; age: 27, 15-37 years; median, range; MELD score: 36, 21-40) and compared with eight healthy controls. Increase in classical monocytes and decrease in patrolling and intermediate monocyte subsets were observed in ALF cohort. HLA-DRlow CD163hi (immune exhaustion), CD64hi (immune complex-mediated response), and CCR2hi (liver homing) monocyte phenotype was noted. CONCLUSION: Altered peripheral monocyte phenotype with enhanced liver homing and macrophage activation, suggests important role of innate immune activation, and provides a potential therapeutic target, in yellow phosphorus-induced hepatotoxicity.

Extra-corporeal non-liver transplant therapies for acute liver failure: Focus on plasma exchange and continuous renal replacement therapy.

The acute inflammatory milieu in patients with acute liver failure (ALF) results in 'toxic' blood in these patients. In vitro experiments have shown that the plasma obtained from ALF patients is toxic to rabbit hepatocytes and inhibits regeneration of rat hepatocytes. Treatments such as plasma exchange and continuous renal replacement therapy to cleanse the blood have improved survival in ALF patients. In the liver microcirculation, the exchange of fluid across fenestrae in liver sinusoidal endothelial cells (LSECs) is vital for proper functioning of hepatocytes. Clogging of the liver filter bed by inflammatory debris and cells ('traffic jam hypothesis') impeding blood flow in sinusoids may in turn reduce the exchange of fluid across LSEC fenestrae and cause dysfunction and necrosis of hepatocytes in ALF patients. In mouse model of paracetamol overdose, disturbances in microcirculation in the liver preceded the development of injury and necrosis of hepatocytes. This may represent a reversible pathophysiological mechanism in ALF which may be improved by the anti-inflammatory effect of plasma exchange. Wider access to urgent plasma exchange is a major advantage compared to urgent liver transplantation to treat ALF patients worldwide, especially so in resource constrained settings. Continuous hemo-filtration or dialysis is used to reduce ammonia levels and treat cerebral edema in ALF patients. In this review, we discuss the different modalities to cleanse the blood in ALF patients, with an emphasis on plasma exchange, from a hepatology perspective.

Low Volume Plasma Exchange and Low Dose Steroid Improve Survival in Patients With Alcohol-Related Acute on Chronic Liver Failure and Severe Alcoholic Hepatitis - Preliminary Experience.

Background: Alcohol-related acute on chronic liver failure (A-ACLF) patients have high short-term mortality and are poor candidates for steroid therapy. Plasma exchange (PLEX) improves survival in ACLF patients. We analyzed our experience with low volume PLEX (50% of plasma volume exchanged per session) and low dose steroids to treat A-ACLF patients. Methods: We retrospectively compared the efficacy of low volume PLEX and low-dose steroids with standard medical treatment (SMT) in A-ACLF patients treated at our center between November 2017 to June 2019. The primary study outcome was one-year survival. Results: Twenty-one A-ACLF patients in PLEX group [age 40 (29-56) years, median (range); MELD score 31 (29-46)] and 29 A-ACLF patients in SMT group [age 41.5 (28-63) years, MELD score 37 (21-48)] were studied. All 50 study patients had severe alcoholic hepatitis [mDF 84.7 (50-389)]. PLEX group patients had 3 (1-7) PLEX sessions with 1.5 (1.4-1.6) liters of plasma exchanged per session and oral Prednisolone 20 mg daily, tapered over 1 month. Kaplan Meier analysis showed better survival over 1 year in the PLEX group compared to the SMT group (P = 0.03). There was renal dysfunction in 10 patients in the PLEX group, which normalized in six patients after PLEX. Conclusion: In this preliminary report, compared to SMT, low volume PLEX and low dose steroid improved survival over one year in A-ACLF patients with severe alcoholic hepatitis. In patients with renal dysfunction, 60% showed improvement in renal function with PLEX. Studies with a larger number of patients are needed to validate these results.

Reticuloendothelial activation correlates with disease severity and predicts mortality in severe alcoholic hepatitis.

BACKGROUND: Overactivation of reticuloendothelial cells lining liver sinusoids - Kupffer cells (macrophages) and sinusoidal endothelial cells - may narrow the sinusoidal lumen, impair perfusion in liver microcirculation and contribute to disease severity in alcoholic hepatitis. AIM: The aim of the article was to assess reticuloendothelial activation in patients with severe alcoholic hepatitis (SAH). METHODS: In SAH patients, we prospectively studied baseline reticuloendothelial activation markers [serum ferritin, sCD163 and plasma von Willebrand factor (VWF) antigen] and Macrophage Activation Syndrome (MAS) criteria, correlated them with disease severity scores [model for end-stage liver disease (MELD) and Sequential Organ Failure Assessment (SOFA) scores] and analyzed their ability to predict survival over a 90-day follow-up period. RESULTS: A total of 50 SAH patients [45 (37-49) years, median (interquartile range), 49 males, discriminant function, 76.2 (54.5-106.6); MELD score, 30 (26.2-36)] were studied. 41 SAH patients (82%) had ferritin >500 ng/mL, and all (100%) had markedly raised sCD163 and VWF levels. The median sCD163 level was 10-fold higher than healthy controls and the median VWF level was 5-fold above the upper limit of normal. In total, 37 SAH patients (74%) met MAS criteria. Reticuloendothelial activation markers correlated with MELD and SOFA scores (P < 0.05). VWF was an independent marker to predict mortality in SAH [adjusted hazard ratio, 1.002 (1.000-1.004)]. CONCLUSIONS: The reticuloendothelial system was markedly activated and correlated with disease severity scores in SAH patients.VWF predicted short-term mortality independent of MELD and sCD163. Further larger multicentric studies are needed to validate these findings.