Histomorphometric study of rat liver during the treatment of the acute toxic injury

Introduction. There are a few effective therapies are available for acute liver injury at present. The aim of the study was to investigate histological and morphometric changes in the liver using models of toxic damage caused by carbon tetrachloride (CCl4 ) and acetaminophen during correction with Oxymethyluracil (OMU). Material and methods. A total of ninety rats were divided into 18 groups. The treatment of acute liver damage models caused by a single injection of CCl4 or acetaminophen was carried out using “Heptor”, “Mexidol”, and OMU. The correction was carried out twice (sacrificed 24 hours after intoxication) and four times (sacrificed 72 hours after intoxication). Liver tissues were processed using standard histological techniques (H&E). A semi-quantitative assessment was performed using a scale based on the severity of liver cell deaths. Results. Twenty-four hours after administration of CCl4 or 72 hours after administration of acetaminophen, the treatment with OMU led to a decrease in liver cell death compared to the group with administration of only CCl4 or acetaminophen. Seventy-two hours after CCl4 and 24 hours after acetaminophen intoxication, these groups with the OMU treatment did not differ from those of the carbon tetrachloride- or acetaminophen-induced liver injury groups, respectively. Conclusion. Thus, on the model of CCl4 liver injury, the treatment with OMU is more effective for 24 hours. In the case of acetaminophen intoxication, the effectiveness of treatment with OMU is better for 72 hours. The results obtained are possibly associated with a different mechanism of the damaging effect of the studied toxicants.

Mitochondrial Mechanisms of Apoptosis and Necroptosis in Liver Diseases

In addition to playing a pivotal role in cellular energetics and biosynthesis, mitochondrial components are key operators in the regulation of cell death. In addition to apoptosis, necrosis is a highly relevant form of programmed liver cell death. Differential activation of specific forms of programmed cell death may not only affect the outcome of liver disease but may also provide new opportunities for therapeutic intervention. This review describes the role of mitochondria in cell death and the mechanism that leads to chronic liver hepatitis and liver cirrhosis. We focus on mitochondrial-driven apoptosis and current knowledge of necroptosis and discuss therapeutic strategies for targeting mitochondrial-mediated cell death in liver diseases.

New Deployable Expandable Electrodes in the Electroporation Treatment in a Pig Model: A Feasibility and Usability Preliminary Study

The aim of the study is to evaluate the usability aspects of new deployable, expandable, electrode prototypes, in terms of suitability solutions for laparoscopic applications on the liver, endoscopic trans-oral and trans-anal procedures, electroporation segmentation in several steps, mechanical functionality (flexibility, penetrability), visibility of the electrode under instrumental guidance, compatibility of the electrode with laparoscopic/endoscopic accesses, surgical instruments, and procedural room and safety compatibility. The electroporation was performed on an animal model (Sus Scrofa Large White 60 kg) both in laparoscopy and endoscopy, under ultrasound guidance, and in open surgery. Electrodes without divergence, with needles coming out straight, parallel to each other, and electrodes with peripheral needles (four needles), diverging from the electrode shaft axis (electrode with non-zero divergence) have been tested. To cause an evaluable necrosis effect, the number of electrical pulses was increased to induce immediate liver cell death. Histological samples were analyzed by staining with Haematoxylin/Eosin or by immunohistochemical staining to confirm complete necrosis. The prototypes of expandable electrodes, tested in laparoscopy and endoscopy and in open surgery, respectively, are suitable in terms of usability, electroporation segmentation in several steps, mechanical functionality (flexibility, penetrability), visibility under instrumental guidance, compatibility with laparoscopic/endoscopic accesses, surgical instruments and procedural room safety, patient safety (no bleeding and/or perforation), and treatment efficacy (adequate ablated volume). Electroporation treatment using new deployable expandable electrode prototypes is safe and feasible. Moreover, electrode configurations allow for a gradual increase in the ablated area in consecutive steps, as confirmed by histology and immunohistochemistry.

An AMPK–caspase-6 axis controls liver damage in nonalcoholic steatohepatitis

Liver cell death has an essential role in nonalcoholic steatohepatitis (NASH). The activity of the energy sensor adenosine monophosphate (AMP)–activated protein kinase (AMPK) is repressed in NASH. Liver-specific AMPK knockout aggravated liver damage in mouse NASH models. AMPK phosphorylated proapoptotic caspase-6 protein to inhibit its activation, keeping hepatocyte apoptosis in check. Suppression of AMPK activity relieved this inhibition, rendering caspase-6 activated in human and mouse NASH. AMPK activation or caspase-6 inhibition, even after the onset of NASH, improved liver damage and fibrosis. Once phosphorylation was decreased, caspase-6 was activated by caspase-3 or -7. Active caspase-6 cleaved Bid to induce cytochrome c release, generating a feedforward loop that leads to hepatocyte death. Thus, the AMPK–caspase-6 axis regulates liver damage in NASH, implicating AMPK and caspase-6 as therapeutic targets.

Urinary acrolein metabolite levels in severe acute alcoholic hepatitis patients

Alcohol-associated liver disease (ALD) remains a major health concern worldwide. Alcohol consumption gives rise to reactive/toxic acrolein, a pathogenic mediator of liver injury in experimental ALD. Elevated acrolein adducts and metabolites are detectable in blood and urine. This study evaluates the major urinary acrolein metabolite, 3-hydroxypropylmercapturic acid (HPMA), in patients with acute alcoholic hepatitis (AAH) and examines its association with disease severity and markers of hepatic inflammation and injury. Urine HPMA was significantly higher in patients with severe [model for end-stage liver disease (MELD) ≥ 20] AAH compared with nonsevere AAH (MELD ≤ 19) or non-alcohol-consuming controls, suggesting that urine HPMA is a novel noninvasive biomarker in severe AAH. The association between HPMA and MELD in patients with AAH was nonlinear. In patients with nonsevere AAH, there was a positive trend, although not significant, whereas in severe AAH the association was negative, indicative of extensive injury and glutathione depletion. Consistent with the multifactorial etiology of ALD, our data identified strong combined effects of HPMA and proinflammatory cytokines on hepatocyte cell death, thereby supporting the pathogenic role of acrolein in liver injury. HPMA, together with IL-1β, showed robust associations with cytokeratin 18 caspase-cleaved fragment (CK18-M30; adjusted R2 = 0.812, P = 0.016) and cytokeratin 18 full-length protein (CK18-M65; adjusted R2 = 0.670, P = 0.048); similarly, HPMA, with IL-8, correlated with CK18-M30 (adjusted R2 = 0.875, P = 0.007) and CK18-M65 (adjusted R2 = 0.831, P = 0.013). The apoptosis index (CK18-M30:CK18-M65 ratio) strongly correlated with HPMA, together with IL-1β (adjusted R2 = 0.777, P = 0.022) or tumor necrosis factor-α (TNFα; adjusted R2 = 0.677, P = 0.046). In patients with severe AAH, IL-1β, IL-8, and TNFα are the predominant proinflammatory cytokines that interact with HPMA and play important mediating roles in influencing the extent/pattern of liver cell death. NEW & NOTEWORTHY This is the first study to examine the urinary acrolein metabolite 3-hydroxypropylmercapturic acid (HPMA) in alcoholic liver disease. HPMA was higher in patients with severe acute alcoholic hepatitis (AAH) compared with controls or nonsevere AAH and may be a novel selective, noninvasive biomarker for severe AAH. Consistent with the multifactorial etiology of alcohol-associated liver disease, we identified strong combined effects of HPMA and proinflammatory cytokines (IL-1β, IL-8, and TNFα) on the extent/pattern of liver cell death, thereby supporting the pathogenic role of acrolein.

Regulation of Hepatic Inflammation via Macrophage Cell Death

Macrophages are innate immune cells with diverse functions including clearing infectious agents, inducing inflammation and fibrosis, resolving fibrosis, and restoring tissue integrity. Liver macrophages consist of both resident Kupffer cells and infiltrating macrophages. They have heterogeneous highly plastic phenotypes, and they change their phenotypes rapidly in response to a diverse array of signals present in the injured or recovering liver. Cell death by apoptosis, necroptosis, or pyroptosis is a common response of liver macrophages to infectious and toxic insults. At the same time, the uptake of apoptotic and other dead cells, efferocytosis, is mediated by a series of dead cell receptors including MerTK, TIM4, and Stablin-1. These generate a critical signal that determines macrophage phenotype evolution. This review discusses the processes that lead to macrophage apoptosis and efferocytosis, and how these alter the course of liver diseases.