Immunohistochemistry and Special Stains in Medical Liver Pathology

Coconut oil affects aging-related changes in Mongolian gerbil liver morphophysiology

Aging causes changes in liver morphophysiology, altering hepatocyte morphology and organ function. Due to its antioxidant and anti-inflammatory properties, coconut oil has been used as a therapeutic agent in diets, in an attempt to attenuate alterations in the liver naturally caused by aging. Herein, we evaluated the effects of coconut oil consumption during aging on Mongolian gerbil liver morphophysiology. The animals were divided into three experimental groups: the gerbils in the Adult Control Group (AC) were euthanized at 3 months of age, the gerbils in the Old Control Group (OC) at 15 months of age, and the gerbils in the Coconut Oil Group (CO) received 0.1 ml/day of coconut oil for 12 months and were euthanized at 15 months of age. Prolonged consumption of coconut oil during aging prevented the animals and the liver from gaining mass. However, the other results showed that coconut oil intensified the morphophysiological alterations of aging, promoting an increase in the hepatocyte cytoplasm and nuclei. In addition, an increase in blood vessels, reticular fibers, lipid droplets, and lipofuscin granules were observed in the CO group. Finally, the results also demonstrated that coconut oil promotes an increase in lipid peroxidation, indicated by an increase in MDA levels. We therefore conclude that coconut oil has the potential to intensify the morphophysiological alterations that occur in the liver during aging.

Regulatory effects of mangiferin on LPS-induced inflammatory responses and intestinal flora imbalance during sepsis

Studies suggest that mangiferin (MAF) has good therapeutic effects on chronic bronchitis and hepatitis. Also, it is one of the antiviral ingredients in Anemarrhena asphodeloides Bunge. However, its effect on the LPS-induced inflammation and intestinal flora during sepsis remains unclear yet. In the present study, LPS-stimulated inflammation RAW264.7 cells and LPS-induced sepsis mice were used to evaluate the efficacy of MAF in vitro and in vivo. 16S rDNA sequencing was performed to analyze the characteristics of intestinal flora of the sepsis mice. It has been demonstrated that MAF (12.5 and 25 μg/mL) significantly inhibited protein expressions of TLR4, MyD88, NF-κB, and TNF-α in the LPS-treated cells and reduced the supernatant TNF-α and IL-6 levels. In vivo, MAF (20 mg/kg) markedly protected the sepsis mice and reduced the serum TNF-α and IL-6 levels. Also, MAF significantly downregulated the protein expressions of TLR4, NF-κB, and MyD88 in the livers. Importantly, MAF significantly attenuated the pathological injuries of the livers and small intestines. Further, MAF significantly increased proportion of Bacteroidota and decreased the proportions of Firmicutes, Desulfobacterota, Actinobacteriota, and Proteobacteria at phylum level, and it markedly reduced the proportions of Escherichia-Shigella, Pseudoalteromonas, Staphylococcus at genus level. Moreover, MAF affects some metabolism-related pathways such as citrate cycle (TCA cycle), lipoic acid metabolism, oxidative phosphorylation, bacterial chemotaxis, fatty acid biosynthesis, and peptidoglycan biosynthesis of the intestinal flora. Thus, it can be concluded that MAF as a treatment reduces the inflammatory responses in vitro and in vivo by inhibiting the TLR4/ MyD88/NF-κB pathway, and corrects intestinal flora imbalance during sepsis to some degree.

Comprehensive Approach to Assessment of Liver Viability During Normothermic Machine Perfusion

Liver transplantation is the most effective treatment of advanced liver disease, and the use of extended criteria donor organs has broadened the source of available livers. Although normothermic machine perfusion (NMP) has become a useful tool in liver transplantation, there are no consistent criteria that can be used to evaluate the viability of livers during NMP. This review summarizes the criteria, indicators, and methods used to evaluate liver viability during NMP. The shape, appearance, and hemodynamics of the liver can be analyzed at a macroscopic level, while markers of liver injury, indicators of liver and bile duct function, and other relevant indicators can be evaluated by biochemical analysis. The liver can also be assessed by tissue biopsy at the microscopic level. Novel methods for assessment of liver viability are introduced. The limitations of evaluating liver viability during NMP are discussed and suggestions for future clinical practice are provided.

Plasma cell myeloma initially diagnosed as light-chain deposition disease on liver biopsy: A case report and literature review

RATIONALE

Light-chain deposition disease (LCDD) is a rare condition characterized by the abnormal deposition of monoclonal light chains (LCs) in multiple organs, leading to progressive organ dysfunction. Herein, we report a case of plasma cell myeloma initially diagnosed as LCDD on liver biopsy performed for prominent cholestatic hepatitis.

PATIENT CONCERNS

A 55-year-old Korean man complained of dyspepsia as the main symptom. On abdominal computed tomography performed at another hospital, the liver showed mildly decreased and heterogeneous attenuation with mild periportal edema. Preliminary liver function tests revealed abnormal results. The patient was treated for an unspecified liver disease; however, his jaundice gradually worsened, prompting him to visit our outpatient hepatology clinic for further evaluation. Magnetic resonance cholangiography revealed liver cirrhosis with severe hepatomegaly of unknown cause. A liver biopsy was performed for the diagnosis. Hematoxylin and eosin staining revealed diffuse extracellular amorphous deposits in perisinusoidal spaces with compressed hepatocytes. The deposits, which morphologically resembled amyloids, were not stained by Congo red but stained strongly positive for kappa LCs and weakly positive for lambda LCs.

DIAGNOSES

Therefore, the patient was diagnosed with LCDD. Further systemic examination revealed a plasma cell myeloma.

INTERVENTIONS

Fluorescence in situ hybridization, cytogenetics, and next-generation sequencing tested in bone marrow showed no abnormalities. The patient initially received bortezomib/lenalidomide/dexamethasone as the treatment regimen for plasma cell myeloma.

OUTCOMES

However, he died shortly thereafter because of coronavirus disease 2019 complications.

LESSONS

This case demonstrates that LCDD may present with sudden cholestatic hepatitis and hepatomegaly, and may be fatal if patients do not receive appropriate and timely treatment because of delayed diagnosis. Liver biopsy is useful for the diagnosis of patients with liver disease of unknown etiology.

Delineation of the healthy rabbit liver by immunohistochemistry - A technical note

Liver diseases pose a big global health problem and liver failure may result from viral infection, overnutrition or tumors. Studying pathologic liver tissue demands for accurate and specific histological stainings and immunohistochemical labellings, including chromogenic and fluorescent approaches. Moreover, a reliable set of healthy liver stainings and labellings are required, to provide a baseline or reference for the pathological situation. Here, we used the liver tissue of a healthy rabbit and compared different histological key steps, such as paraffin embedding after formalin fixation versus cryopreservation; or an antigen retrieval (AR) step in processing paraffin sections versus the same procedure without AR; or chromogenic with fluorescent detection system, respectively. Moreover, we provide images of serial sections, where we stained the same morphological structure with different markers, including collagen I, collagen III, fibronectin, α-SMA, elastin, protease-activated receptor-2 (PAR-2) which is an inflammation-related marker, ki67 for proliferating cells, and orcein (as negative control for pathological aberrations like Wilson disease). Differences between conditions were quantitatively assessed by measuring the colour intensity. Generally, we observed that cryosections exhibited a stronger signal intensity in immunohistochemically labelled sections than in paraffin sections; however, the strong staining got slurred, which sometimes hampered proper identification of morphological structures at higher magnifications. Moreover, there was a clear increase in signal intensity for paraffin sections when an AR step was performed compared to condition without AR. Results for mouse isotype staining as a negative control clearly supported those findings. Different stainings of the portal triad, the central vein and the bile ducts revealed a clear-cut distribution of extracellular matrix components, with prominent fibronectin and elastin around the lumen of the central vein as well as a patchy PAR-2 expression. As for the bile ducts, complete absence of α-SMA and PAR-2 was found at the margins, however, collagen I expression and elastin were positive and showed a strong signal. Like this, we provide useful and valuable reference images for researchers using the rabbit liver model. It may help to decide which of the immunohistochemical protocols are valuable to reach a certain aim and which protocols lead to the best visualization of the target structure.

Amyloid-like Fibronectin Deposits in the Liver: A Novel Morphologic Finding

Amyloid deposits in the liver are recognized by their hematoxylin and eosin (H&E) findings, consisting of acellular eosinophilic deposits in various compartments of the liver parenchyma, including the stroma, vessels, and rarely the hepatocytes. H&E findings that suggest amyloid are then confirmed by Congo red stains and subtyped when clinically needed. Two cases are reported with sinusoidal deposits of acellular material that closely mimicked amyloid on H&E, but were Congo red negative. Mass spectrometry-based proteomic analysis identified the material as fibronectin. In 1 case, the deposits were located in the sinusoids of a well-differentiated hepatocellular carcinoma and in 1 case in the sinusoids of a benign liver.

L-carnitine supplementation attenuates NAFLD progression and cardiac dysfunction in a mouse model fed with methionine and choline-deficient diet

Non-alcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disorder. NAFLD, associated lipotoxicity, fibrosis, oxidative stress, and altered mitochondrial metabolism, is responsible for systemic inflammation, which contributes to organ dysfunction in extrahepatic tissues, including the heart. We investigated the ability of L-carnitine (LC) to oppose the pathogenic mechanisms underlying NAFLD progression and associated heart dysfunction, in a mouse model of methionine-choline-deficient diet (MCDD). Mice were divided into three groups: namely, the control group (CONTR) fed with a regular diet and two groups fed with MCDD for 6 weeks. In the last 3 weeks, one of the MCDD groups received LC (200 mg/kg each day) through drinking water (MCDD + LC). The hepatic lipid accumulation and oxidative stress decreased after LC supplementation, which also reduced hepatic fibrosis via modulation of α-smooth muscle actin (αSMA), peroxisome-activated receptor gamma (PPARγ), and nuclear factor kappa B (NfƙB) expression. LC ameliorated systemic inflammation, mitigated cardiac reactive oxygen species (ROS) production, and prevented fibrosis progression by acting on signal transducer and activator of transcription 3 (STAT3), extracellular signal-regulated kinase 1-2 (ERK1-2), and αSMA. This study confirms the existence of a relationship between fatty liver disease and cardiac abnormalities and highlights the role of LC in controlling liver oxidative stress, steatosis, fibrosis, and NAFLD-associated cardiac dysfunction.

Mouse Models of Nonalcoholic Steatohepatitis: Toward Optimization of Their Relevance to Human Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) arises from a variable interplay between environmental factors and genetic determinants that cannot be completely replicated in animals. Notwithstanding, preclinical models are needed to understand NASH pathophysiology and test mechanism-based therapies. Among several mouse models of NASH, some exhibit the key pathophysiologic as well as histopathologic criteria for human NASH, whereas others may be useful to address specific questions. Models based on overnutrition with adipose restriction/inflammation and metabolic complications, particularly insulin resistance, may be most useful to investigate critical etiopathogenic factors. In-depth pathologic description is required for all models. Some models demonstrate hepatocyte ballooning, which can be confused with microvesicular steatosis, whereas demonstration of an inflammatory infiltrate and pattern of liver fibrosis compatible with human NASH is desirable in models used for pharmacologic testing. When mice with specific genetic strains or mutations that cause overeating consume a diet enriched with fat, modest amounts of cholesterol, and/or simple sugars ("Western diet"), they readily develop obesity with liver disease similar to human NASH, including significant fibrosis. Purely dietary models, such as high-fat/high-cholesterol, Western diet, and choline-deficient, amino acid-defined, are similarly promising. We share concern about using models without weight gain, adipose pathology, or insulin resistance/hyperinsulinemia and with inadequate documentation of liver pathology. NASH-related fibrosis is a key endpoint in trials of possible therapies. When studied for this purpose, NASH models should be reproducible and show steatohepatitis (ideally with ballooning) and at least focal bridging fibrosis, while metabolic factors/disordered lipid partitioning should contribute to etiopathogenesis. Because murine models are increasingly used to explore pharmacologic therapies for NASH, we propose a minimum set of requirements that investigators, drug companies, and journals should consider to optimize their translational value.