Role of microbubble ultrasound contrast agents in the non-invasive assessment of chronic hepatitis C-related liver disease

Patients who are chronically infected with the hepatitis C virus often develop chronic liver disease and assessment of the severity of liver injury is required prior to considering viral eradication therapy. This article examines the various assessment methods currently available from gold standard liver biopsy to serological markers and imaging. Ultrasound is one of the most widely used imaging modalities in clinical practice and is already a first-line diagnostic tool for liver disease. Microbubble ultrasound contrast agents allow higher resolution images to be obtained and functional assessments of microvas-cular change to be carried out. The role of these agents in quantifying the state of hepatic injury is discussed as a viable method of determining the stage and grade of liver disease in patients with hepatitis C. Although currently confined to specialist centres, the availability of microbubble contrast-enhanced ultrasound will inevitably increase in the clinical setting.     

Drug-induced autoimmune hepatitis: A minireview

Drug-induced autoimmune hepatitis (DIAIH) is a specific phenotype of drug-induced liver injury that may lead to the devastating outcome of acute liver failure requiring liver transplantation. Drugs implicated in DIAIH include antimicrobials such as nitrofurantoin and minocycline, non-steroidal anti-inflammatory drugs, statins as well as anti-tumor necrosis agents. The clinical features of drug-induced liver injury are indistinguishable from idiopathic autoimmune hepatitis (AIH) as both may have positive AIH-related autoantibodies, elevated immunoglobulin G, as well as similar histopathological findings. In patients who show no clinical improvement, or there is progressive liver injury despite cessation of the suspected drug, a liver biopsy should be considered, whereby the presence of advance fibrosis on histology favors the diagnosis of idiopathic AIH. Empirical treatment with corticosteroids may be required in patients with non-resolving liver injury. A typical clinical scenario supportive of DIAIH includes a history of drug exposure with spontaneous resolution of liver injury after drug withdrawal and the absence of relapse after rapid steroid taper. In this article we report two cases of DIAIH secondary to Sorafenib and Atorvastatin along with a review of currently available literature. Early identification and treatment often lead to a favorable outcome in DIAIH.     

The brain in acute on chronic liver failure

Acute-on-chronic liver failure (ACLF) is a newly defined clinical entity with significant morbidity and mortality (~40–90 % at 1 year dependent on need for organ support at presentation). It defines a presentation with acute severe liver injury, often with multiorgan dysfunction, on a background of previously known or unknown cirrhosis. In its severest form, it is almost indistinguishable from acute liver failure, as similarly in around 5 % may rapidly progress to intracranial hypertension and cerebral oedema culminating in coma and/or death. Our understanding of such cerebral sequelae is currently limited to clinical observation, though our knowledge base is rapidly expanding since recent consensus clinical definition and guidance. Moreover, there are now animal models of ACLF and imaging modalities to better characterize events in the brain that occur with ACLF. However, as yet there has been little in the way of interventional study of this condition which are much needed. In this review we dissect existing clinical and experimental data to better characterise the manifestations of ACLF on the brain and allow for the development of targeted therapy as currently the plethora of existing interventions were designed to treat either the effects of cirrhosis or acute liver injury independently.     

Mechanisms and consequences of COVID-19 associated liver injury: What can we affirm?

Since the first reports of coronavirus disease 2019(COVID-19) cases in December 2019 in China, numerous papers have been published describing a high frequency of liver injury associated with severe acute respiratory syndrome coronavirus 2 infection, many of them proposing a link between these findings and patient outcomes. Increases in serum aminotransferase levels(ranging from 16% to 62%) and bilirubin levels(ranging from 5% to 21%) have been reported and seem to be more often observed in patients with severe forms of COVID-19. Although absolute changes in these parameters are frequently seen, other variables, such as the ratio above the upper limit of normal, the onset of liver injury as a complication in severe cases and histopathological findings, reinforce that liver changes are of dubious clinical relevance in the course of this disease. Other factors must also be considered in these analyses, such as the repercussions of hemodynamic changes, the presence of thrombotic events, and, mainly, the possible drug-induced liver injury with the current, yet off-label, treatment. This paper aimed to analyze the currently available data on liver injury in patients with COVID-19.     

心源性肝损害对心力衰竭的影响

心力衰竭（HF）是当今威胁人类健康的重大临床问题，住院率、死亡率极高。心脏与肝脏之间相互作用的研究较少，相关研究表明HF容易诱发肝功能损害。心源性肝损害临床表现主要包括:腹胀、间断性右上腹不适、恶心、厌食，通常被误认为是胃肠道疾病，往往忽略其对HF的影响。肝功能指标（如TB、GGT、白蛋白）对HF的严重程度及预后均有独立预测价值。而心源性肝损害导致肝脏药代动力学紊乱，使临床用药如履薄冰，应及早重视、干预心源性肝损害，达到个体化治疗，以改善HF症状及预后，降低死亡率。     

Heatstroke: Its Clinical and Pathological Presentation, with Particular Attention to the Liver

Heatstroke is a potentially fatal disorder caused by an extreme elevation of body temperature. It is the most severe of the illnesses produced as a result of a high ambient temperature; however, it also may occur sporadically among individuals working or exercising in more favorable weather conditions, particularly early in their training before acclimatization occurs. The liver is a common site of tissue injury in cases of heatstroke and can be the site of fatal tissue injury in cases that survive the initial neurologic injury. Prompt early recognition of heatstroke as the entity responsible for a given patient's problems and effective early cooling with attention to expected complications can result in complete recovery in most cases. In a minority (< 10%) in whom neurologic injury has not resulted in an early death occurring within the first 2-3 days, the hepatic injury due to heatstroke can result in death that occurs a week or more after the onset of the heat stress, unless the liver is replaced. Recently, two such cases have been referred to the University of Pittsburgh for transplantation. On the basis of these two referrals and a review of the literature, we believe that this problem occurs more often than is currently appreciated, principally because of a lack of knowledge about the problem. In an attempt to correct this information deficit, this review was prepared.     

Liver stem cells:Plasticity of the liver epithelium

The liver has a high regenerative capacity after acute liver injury, but this is often impaired during chronic liver injury. The existence of a dedicated liver stem cell population that acts as a source of regeneration during chronic liver injury has been controversial. Recent advances in transgenic models and cellular reprogramming have provided new insights into the plasticity of the liver epithelium and directions for the development of future therapies. This article will highlight recent findings about the cellular source of regeneration during liver injury and the advances in promoting liver regeneration.     

Transient liver injury caused by gefitinib]

Gefitinib blocks epidermal growth factor receptor autophosphorylation and subsequently the signal transduction pathways implicated in proliferation, metastasis, invasion, and angiogenesis. Reported adverse reactions to gefitinib include liver injury that is not fully understood. Liver injury was observed in 5 (12.2%) of 41 patients with non-small cell lung cancer who received gefinitib monotherapy. Onset of liver injury was seen between 28 and 56 days after initiation of administration. Two patients had Grade 2 liver injury and 3 patients, Grade 3. In 4 patients, liver injury was temporary, lasting during a period of continuous gefitinib administration. In another patient, gefitinib was discontinued because of the onset of liver injury, which improved when gefitinib administration was restarted. Gefitinib is necessary in most patients whose lung cancer is refractory to cytotoxic chemotherapy, because no other treatment regimens are available at present. The rate of liver injury in cases treated with gefitinib is high, and so it is necessary to observe liver function carefully, but the liver injury due to this drug is often transient. However, the use of gefitinib in many cases appears to be a necessity.     

Evaluation of the role of nuclear factor-kappaB signaling in liver injury using genetic animal models

Most chronic liver diseases are not sufficiently treatable at present and very often progress to liver fibrosis and liver cirrhosis. Several recent studies have suggested that cytokines and cytokine-activated inflammatory signaling pathways might play an important role in the mediation of liver injury. Although pro-inflammatory signaling pathways such as nuclear factor (NF)-kappaB have evolved primarily for host defense to infections, they appear to be involved in the pathogenesis of inflammatory diseases and may mediate liver injury in response to a variety of agents and pathogens. Herein is summarized briefly some recent findings concerning the role of NF-kappaB in different models of liver injury based on transgenic and knockout animal technology.     

Abnormal liver function tests associated with severe rhabdomyolysis

Rhabdomyolysis is a syndrome of skeletal muscle injury with release of cellular constituents such as potassium,phosphate,urate and intracellular proteins such as myoglobin into the circulation,which may cause complications including acute kidney injury,electrolyte disturbance and cardiac instability.Abnormal liver function tests are frequently observed in cases of severe rhabdomyolysis.Typically,there is an increase in serum aminotransferases,namely aspartate aminotransferase and alanine aminotransferase.This raises the question of liver injury and often triggers a pathway of investigation which may lead to a liver biopsy.However,muscle can also be a source of the increased aminotransferase activity.This review discusses the dilemma of finding abnormal liver function tests in the setting of muscle injury and the potential implications of such an association.It delves into some of the clinical and experimental evidence for correlating muscle injury to raised aminotransferases,and discusses pathophysiological mechanisms such as oxidative stress which may cause actual liver injury.Serum aminotransferases lack tissue specificity to allow clinicians to distinguish primary liver injury from muscle injury.This review also explores potential approaches to improve the accuracy of our diagnostic tools,so that excessive or unnecessary liver investigations can be avoided.     

CASE REPORT: Troglitazone-Induced Fulminant Hepatic Failure

The three reported cases demonstrate that troglitazone is an idiosyncratic hepatotoxin that can lead to irreversible liver injury. Thus, troglitazone should be prescribed with caution and should not be used as a first-line agent in the treatment of type II DM when potentially less toxic alternatives are available. It remains to be seen whether the hepatotoxicity associated with troglitazone is a drug-class effect or specific to troglitazone. Other thiazolidinediones currently in clinical trials may be able to provide the therapeutic benefits of troglitazone without significant hepatotoxicity. If troglitazone is used, frequent monitoring of serum aminotransferases and symptoms is mandatory. However, as illustrated by these and other cases reported to date, the onset of troglitazone-induced liver injury is insidious and temporally variable. Thus, the value of close monitoring and when, if ever, it is safe to stop such monitoring are currently unclear.     

Steatosis: co-factor in other liver diseases

The prevalence of fatty liver is rising in association with the global increase in obesity and type 2 diabetes. In the past, simple steatosis was regarded as benign, but the presence of another liver disease may provide a synergistic combination of steatosis, cellular adaptation, and oxidative damage that aggravates liver injury. In this review, a major focus is on the role of steatosis as a co-factor in chronic hepatitis C (HCV), where the mechanisms promoting fibrosis and the effect of weight reduction in minimizing liver injury have been most widely studied. Steatosis, obesity, and associated metabolic factors may also modulate the response to alcohol- and drug-induced liver disease and may be risk factors for the development of hepatocellular cancer. The pathogenesis of injury in obesity-related fatty liver disease involves a number of pathways, which are currently under investigation. Enhanced oxidative stress, increased susceptibility to apoptosis, and a dysregulated response to cellular injury have been implicated, and other components of the metabolic syndrome such as hyperinsulinemia and hyperglycemia are likely to have a role. Fibrosis also may be increased as a by-product of altered hepatocyte regeneration and activation of bipotential hepatic progenitor cells. In conclusion, active management of obesity and a reduction in steatosis may improve liver injury and decrease the progression of fibrosis.     

Approaches to liver biopsy techniques--revisited

Within the spectrum of diagnostic procedures in hepatology, the procurement of a liver specimen plays an important role. Although diagnostic tests that employ seroimmunological, biochemical, molecular biologic, functional, as well as imaging techniques are capable of establishing the etiology of a chronic or acute liver disease, in most instances the gold standard for the assessment of stage as a common end point of progressive liver diseases is the histological evaluation of a liver sample. Since the first documented biopsy by Paul Ehrlich in 1883 by aspiration, the method has been diversified to encompass not only different needle types for cutting and aspiration but also different routes proceeding transvenously or transcutaneously, and in the combination with imaging modalities such as ultrasound, computed tomography, and laparoscopy. Standard liver biopsies can be rapidly performed and have an accepted mortality rate between 0.1% and 0.01%. The decision between different techniques is based upon the risk profile of the patient who very often has advanced liver failure with coagulopathy and ascites on the one hand and the underlying disease on the other hand. Although standard liver biopsy in hepatitis C infection or suspected rejection in a transplant patient is often sufficient, a laparoscopically guided biopsy can be of value in diseases such as primary sclerosing cholangitis or suspected metastatic disease, which are characterized by a zonal affection of the liver and possibly the peritoneum. Coagulopathy may lead to transjugular or plugged biopsies, and the workup of undetermined hepatic masses may favor ultrasound-guided aspiration cytology. Among the most feared complications of liver biopsies are hemorrhage, seeding of cancer cells, infections, and injury to the viscera. In view of these complications, a careful assessment of the clinical question, the appropriate invasive approach, and an expected management consequence are necessary. This requires a detailed consideration of the differences of biopsy techniques currently available to the clinical hepatologist.     

Etiology and management of liver injury in patients with COVID-19

The outbreak of novel coronavirus disease 2019(COVID-19) has resulted in global emergence. With the expansion of related research, in addition to respiratory symptoms, digestive system involvement such as nausea, vomiting, and diarrhea have also been reported with COVID-19. Besides, abnormal liver function is also frequent in biochemical tests of COVID-19 patients, which is correlated with the severity and mortality of the disease course. The etiology of liver injury in patients with COVID-19 might include viral immunologic injury, drug-induced liver injury, the systemic inflammatory response, hypoxic hepatitis, and the exacerbation of preexisting liver disease. Although liver injuries in COVID-19 are often transient and reversible, health workers need to pay attention to preexisting liver disease, monitor liver function, strengthen supportive treatment, and reduce the chance of drug-induced liver injury. This article reviews the epidemiological characteristics, etiology, management, and preventive strategies for liver injury in patients with COVID-19.     

Acute liver injury following <Emphasis Type="Italic">Garcinia cambogia</Emphasis> weight-loss supplementation: case series and literature review

Herbal weight-loss supplements are sold as self-medication products, and are often used under the misconception that their natural origin guarantees their safety. Food supplements are not required to provide any benefit/risk profile evaluation before marketing; however, possible risks associated with use of herbal extracts in food supplements are becoming more and more documented in the literature. Some herbs are listed as the leading cause of herb-induced liver injury, with a severe or potentially lethal clinical course, and unpredictable herb–drug interactions. Garcinia cambogia (GC) extract and GC-containing products are some of the most popular dietary supplements currently marketed for weight loss. Here, we present four cases of acute liver failure in women taking GC extract for weight loss, and a literature review of clinical evidences about hepatic toxicity in patients taking dietary supplements containing GC extract.     

Difficulties in diagnosing acute kidney injury post liver transplantation using serum creatinine based diagnostic criteria

Renal function in patients with advanced cirrhosis is an important prognostic factor for survival both prior to and following liver transplantation. The importance of renal function is reflected by the introduction of the model for end stage liver disease(MELD) score, which includes serum creatinine. The MELD score has been shown to predict the short term risk of death for transplant wait listed patients and is currently used by many countries to allocate liver transplants on the basis of severity of underlying illness. Changes in serum creatinine are also used to stage acute kidney injury. However prior to liver transplantation the serum creatinine typically over estimates underlying renal function, particularly when a colorimetric Jaffe based assay is used, and paradoxically then under estimates renal function post liver transplantation, particularly when immunophyllins are started early as part of transplant immunosuppression. As acute kidney injury is defined by changes in serum creatinine, this potentially leads to over estimation of the incidence and severity of acute kidney injury in the immediate post-operative period.     

Alcohollike liver disease in nonalcoholics. A clinical and histologic comparison with alcohol-induced liver injury

Individuals who deny alcohol consumption may develop liver injury that histologically resembles the liver injury found in alcoholic patients. To determine whether any clinical or histologic features distinguish alcoholic and nonalcoholic subjects with "alcohollike" liver injury, the clinical records and liver biopsy specimens of 68 alcoholic and 39 nonalcoholic patients with alcohollike injury on liver biopsy were compared. The clinical and biochemical features of the two groups differed significantly. Alcoholism was associated with more severe clinical and biochemical manifestations of liver disease. However, there was considerable overlap among histologic features of the two clinically defined groups. Based on histology alone, alcoholic and nonalcoholic patients were often indistinguishable. The observations suggest that the clinical differences between the alcoholic and non-alcoholic patients cannot be attributed to qualitative or quantitative differences in liver histology. On the other hand, histologic similarities between the two groups raise the possibility that a shared condition, perhaps nutritional or hormonal, is responsible for the histologic expression of alcohollike injury in both groups.     

Clinical evidence for the regression of liver fibrosis

Fibrosis is a common pathological process for the majority of liver diseases which in a significant minority of patients leads to end-stage cirrhosis and/or hepatocellular carcinoma. Data emerging from small rodent models of chronic liver disease have demonstrated that fibrotic extracellular matrix can be remodelled and near-normal hepatic architecture regenerated upon cessation of injury. Moreover, regression of liver fibrosis in these model systems can be stimulated with drugs that target the activities of fibrogenic hepatic stellate cells. These findings are exciting as they suggest that established fibrosis is susceptible to regression and possibly even reversion. Alongside these experimental studies is a growing body of clinical data that suggest regression of fibrosis may also occur in liver disease patients for whom an effective treatment is available for their underlying liver injury. This paper provides an up-to-date review of the currently available clinical data and also considers technical caveats that highlight the need for caution in establishing a new dogma that human liver fibrosis is reversible.     

Acetaminophen‐induced hepatic neutrophil accumulation and inflammatory liver injury in CD18‐deficient mice

Background: Acetaminophen (APAP) hepatotoxicity is currently the most frequent cause of acute liver failure in the US and many European countries. Although intracellular signalling mechanisms are critical for hepatocellular injury, a contribution of inflammatory cells, especially neutrophils, has been suggested. However, conflicting results were obtained when using immunological intervention strategies. Aims: The role of neutrophils was investigated using a CD18‐deficient mouse model. Results: Treatment of C57Bl/6 wild type mice with 300 mg/kg APAP resulted in severe liver cell necrosis at 12 and 24 h. This injury was accompanied by formation of cytokines and chemokines and accumulation of neutrophils in the liver. However, there was no difference in the inflammatory response or liver injury in CD18‐deficient mice compared with wild‐type animals. In contrast to treatment with endotoxin, no upregulation of CD11b or priming for reactive oxygen was observed on neutrophils isolated from the peripheral blood or the liver after APAP administration. Furthermore, animals treated with endotoxin 3 h after APAP experienced an exaggerated inflammatory response as indicated by substantially higher cytokine and chemokine formation and twice the number of neutrophils in the liver. However, liver injury in the two‐hit model was the same as with APAP alone. Conclusions: Our data do not support the hypothesis that neutrophils contribute to APAP hepatotoxicity or that a neutrophil‐mediated injury phase could be provoked by a second, pro‐inflammatory hit. Thus, APAP‐induced liver injury in mice is dominated by intracellular mechanisms of cell death rather than by neutrophilic inflammation.