Low-grade elevation of fibrinogen-degradation products is an important parameter to identify acute presentation of autoimmune hepatitis

A diagnostic model of autoimmune hepatitis in unknown liver injury based on noninvasive clinical data

All the diagnostic criteria of autoimmune hepatitis (AIH) include histopathology. However, some patients may delay getting this examination due to concerns about the risks of liver biopsy. Therefore, we aimed to develop a predictive model of AIH diagnostic that does not require a liver biopsy. We collected demographic, blood, and liver histological data of unknown liver injury patients. First, we conducted a retrospective cohort study in two independent adult cohorts. In the training cohort (n = 127), we used logistic regression to develop a nomogram according to the Akaike information criterion. Second, we validated the model in a separate cohort (n = 125) using the receiver operating characteristic curve, decision curve analysis, and calibration plot to externally evaluate the performance of this model. We calculated the optimal cutoff value of diagnosis using Youden's index and presented the sensitivity, specificity, and accuracy to evaluate the model in the validation cohort compared with the 2008 International Autoimmune Hepatitis Group simplified scoring system. In the training cohort, we developed a model to predict the risk of AIH using four risk factors-The percentage of gamma globulin, fibrinogen, age, and AIH-related autoantibodies. In the validation cohort, the areas under the curve for the validation cohort were 0.796. The calibration plot suggested that the model had an acceptable accuracy (p > 0.05). The decision curve analysis suggested that the model had great clinical utility if the value of probability was 0.45. Based on the cutoff value, the model had a sensitivity of 68.75%, a specificity of 76.62%, and an accuracy of 73.60% in the validation cohort. While we diagnosed the validated population by using the 2008 diagnostic criteria, the sensitivity of prediction results was 77.77%, the specificity was 89.61% and the accuracy was 83.20%. Our new model can predict AIH without a liver biopsy. It is an objective, simple and reliable method that can effectively be applied in the clinic.

Microcirculatory disturbance in acute liver injury

Microcirculatory disturbance is thought to be involved in the pathogenesis of acute liver injury (ALI). The current study examined the pathophysiologic role of hepatic microcirculatory disturbance in patients with ALI and in mouse models of ALI. Using serum aminotransferase (ALT)/lactate dehydrogenase (LDH) ratio as a hypoxic marker, 279 patients with ALI were classified into the low ALT/LDH ratio (ALT/LDH ≤1.5) and high ALT/LDH ratio group (ALT/LDH >1.5). In the low ALT/LDH ratio group, serum ALT, LDH, fibrinogen degradation products and prothrombin time-international normalized ratio were increased relative to the high ALT/LDH ratio group. Histologically, hepatic expression of tissue factor (TF) and hypoxia-related proteins was enhanced in the low ALT/LDH ratio group, and this was accompanied by sinusoidal fibrin deposition. Sinusoidal hypercoagulation and intrahepatic hypoxia was also analyzed in two different mouse models of ALI; Concanavalin A (ConA) mice and Galactosamine/tumor necrosis factor (TNF)-α (G/T) mice. Serum ALT/LDH ratio in ConA mice was significantly lower compared with G/T mice. Pimonidazole staining revealed the upregulation of hypoxia-related proteins in ConA mice. Recombinant human soluble thrombomodulin improved liver damage in ConA mice in association with reduced sinusoidal hypercoagulation and intrahepatic hypoxia. The present study provides evidence that serum ALT/LDH ratio aids in the identification of patients with ALI and intrahepatic hypoxia as a result of microcirculatory disturbance. The results facilitate the improved understanding of the pathogenesis of ALI, thereby offering a novel therapeutic strategy against ALI, which arises from sinusoidal hypercoagulation.