The utility of liver biopsy in 2020

PURPOSE OF REVIEW

Over the past decade, imaging modalities and serological tests have emerged as important tools in the evaluation of liver diseases, in many cases supplanting the use of liver biopsy and histological examination. Nonetheless, the accuracy and diagnostic value of these methods may not always be conclusive and the assessment of liver histology often remains the gold standard for diagnostic evaluation. The purpose of this review is to summarize the current role of liver biopsy in contemporary hepatology practice.

RECENT FINDINGS

Technical factors were found to influence the diagnostic value of liver biopsy and histological examination of the liver, including specimen number and size (preferably ≥3 nonfragmented specimens of >20 mm in length), needle diameter (1.6 mm Menghini), number of passes (mean 2.5), imaging-guidance, and operator experience. Liver biopsy was demonstrated to be diagnostically valuable in the evaluation of persistently abnormal liver tests of unclear cause, with histology pointing to a specific diagnosis in 84% of patients. Although coagulation abnormalities continue to be an important concern when performing liver biopsy, their influence on complication risk remains unclear. Implementation of less stringent preprocedural coagulation thresholds decreased preprocedural transfusions without increasing the bleeding rate. Serious complications associated with percutaneous liver-biopsy (PLB) and transjugular liver-biopsy are similar, but pain appears to be more common with PLB.

SUMMARY

Histopathological evaluation continues to be fundamentally important in assessing hepatic disease, and liver histology remains the most accurate approach to assess fibrosis and assign prognosis.

Signatures in drug-induced liver injury

PURPOSE OF REVIEW

Drug-induced liver injury (DILI) can be induced by a myriad of drugs. Assessing whether the patient has DILI and assessing which drug is the most likely culprit are challenging. There has been too little attention paid to the concept that certain drugs appear to have unique clinical features or 'phenotypes'.

RECENT FINDINGS

Several case series of DILI because of various drugs have been published, and analysis of these case series points to the fact that individual drugs have characteristic DILI signatures. These clinical phenotypes can be characterized by latency, biochemical features (R-value), as well as clinical symptoms and signs. Several drugs, including isoniazid, amoxicillin-clavulanic acid, anabolic steroids, β-interferon and others, have highly unique clinical features. Such unique properties may be able to be used to improve adjudication processes.

SUMMARY

Individual drugs have unique clinical DILI phenotypes or signatures. Furthermore, these may be able to be used to improve adjudication.

Impact of Patient-Level Characteristics on In-hospital Mortality After Interhospital Transfer to Medicine Services: an Observational Study

BACKGROUND

National administrative datasets have demonstrated increased risk-adjusted mortality among patients undergoing interhospital transfer (IHT) compared to patients admitted through the emergency department (ED).

OBJECTIVE

To investigate the impact of patient-level data not available in larger administrative datasets on the association between IHT status and in-hospital mortality.

DESIGN

Retrospective cohort study with logistic regression analyses to examine the association between IHT status and in-hospital mortality, controlling for covariates that were potential confounders. Model 1: IHT status, admit service. Model 2: model 1 and patient demographics. Model 3: model 2 and disease-specific conditions. Model 4: model 3 and vital signs and laboratory data.

PARTICIPANTS

Nine thousand three hundred twenty-eight adults admitted to Medicine services.

MAIN MEASURES

Interhospital transfer status, coded as an unordered categorical variable (IHT vs ED vs clinic), was the independent variable. The primary outcome was in-hospital mortality. Secondary outcomes included unadjusted length of stay and total cost.

KEY RESULTS

IHT patients accounted for 180 out of 484 (37%) in-hospital deaths, despite accounting for only 17% of total admissions. Unadjusted mean length of stay was 8.4 days vs 5.6 days (p < 0.0001) and mean total cost was $22,647 vs $12,968 (p < 0.0001) for patients admitted via IHT vs ED respectively. The odds ratios (OR) for in-hospital mortality for patients admitted via IHT compared to the ED were as follows: model 1 OR, 2.06 (95% CI 1.66-2.56, p < 0.0001); model 2 OR, 2.07 (95% CI 1.66-2.58, p < 0.0001); model 3 OR, 2.07 (95% CI 1.63-2.61, p < 0.0001); model 4 OR, 1.70 (95% CI 1.31-2.19, p < 0.0001). The AUCs of the models were as follows: model 1, 0.74; model 2, 0.76; model 3, 0.83; model 4, 0.88, consistent with a good prediction model.

CONCLUSIONS

Patient-level characteristics affect the association between IHT and in-hospital mortality. After adjusting for patient-level clinical characteristics, IHT status remains associated with in-hospital mortality.

Sedation During Endoscopy in Patients with Cirrhosis: Safety and Predictors of Adverse Events

BACKGROUND

Sedation during endoscopy in cirrhotic patients is typically via moderate sedation, most commonly using a combination of a benzodiazepine (i.e., midazolam) and narcotic (i.e., fentanyl) or with propofol using monitored anesthesia care (MAC). Here, we examined the safety of moderate sedation and MAC in patients with cirrhosis.

METHODS

This retrospective cohort study of cirrhotic patients undergoing endoscopy from a large academic medical center between 2010 and 2014 examined extensive clinical data including the following: past history, physical findings, laboratory results, and procedural adverse events. Adverse events were defined a priori and included hypoxia, hypotension, bleeding, and death.

RESULTS

We identified 2618 patients with cirrhosis who underwent endoscopic procedures; the mean age was 56 years, 36% were female, the mean Child-Pugh score was 9.3 (IQR: 8, 11), and Charlson Comorbidity Index score was 3.2 (IQR: 1, 4); 1157 had MAC; and 1461 had moderate sedation. There was no difference in the frequency of adverse events in MAC and moderate sedation groups, with a total of 15 adverse events (7/1157 MAC and 8/1461 moderate sedation). The most common procedure performed was esophagogastroduodenoscopy (EGD, n = 1667) and was associated with 10 adverse events. Overall, adverse events included bradycardia (1), hypoxia (7), bleeding (5), laryngospasm (1), and perforation (1). The frequency was similar for EGD, ERCP, and colonoscopy-each at a rate of 0.6%.

CONCLUSIONS

Adverse events in cirrhotic patients undergoing endoscopy appeared to be similar with moderate sedation or MAC, and the frequency was the same for different types of procedures.

Blood transfusion practices in upper gastrointestinal bleeding: response to a landmark study

OBJECTIVE

Lack of clear evidence in red blood cell (RBC) transfusion during gastrointestinal bleeding has led to varied recommendations over the years. However, studies in broad areas of medicine have provided evidence about appropriate RBC transfusion thresholds, and a 'landmark' study published in 2013 provided evidence in patients with upper gastrointestinal (UGI) bleeding. We hypothesized that the response to the evidence would lead to improved RBC transfusion practice. Our aim was to determine the response in RBC transfusion practices at our institution.

DESIGN

We examined RBC transfusion practices in patients with UGI bleeding who presented to the Medical University of South Carolina from January 2010 through December 2013. We abstracted extensive clinical data including demographic, medical history (comorbidities), medications, physical examination findings, laboratory data, endoscopic data, and RBC transfusion practices. We considered appropriate RBC transfusion to have occurred when performed for a hemoglobin level of <70 g/L.

RESULTS

270 patients hospitalized with UGI bleeding had 606 RBC transfusions; 355 transfusions in 107 patients were appropriate, and 251 transfusions in 163 were inappropriate. In 2010, 2011, and 2012, the rates of appropriate RBC transfusions were 61/124 (49%), 92/172 (53%), and 84/142 (59%), respectively. There was a statistically significant difference in appropriate transfusions in 2013 (118/168 (70%)) compared with 2012 (84/142 (59%), p=0.003), as well as during 2010-2012 (237/438 (54%), p≤0.003).

CONCLUSIONS

The data suggest that there was an improvement in RBC transfusion practices after a landmark study. However, the data also highlight that RBC transfusion practices in UGI bleeding remain imperfect.

Signaling through the interleukin-4 and interleukin-13 receptor complexes regulates cholangiocyte TMEM16A expression and biliary secretion

TMEM16A is a Ca²⁺-activated Cl^- channel in the apical membrane of biliary epithelial cells, known as cholangiocytes, which contributes importantly to ductular bile formation. Whereas cholangiocyte TMEM16A activity is regulated by extracellular ATP-binding membrane purinergic receptors, channel expression is regulated by interleukin-4 (IL-4) through an unknown mechanism. Therefore, the aim of the present study was to identify the signaling pathways involved in TMEM16A expression and cholangiocyte secretion. Studies were performed in polarized normal rat cholangiocyte monolayers, human Mz-Cha-1 biliary cells, and cholangiocytes isolated from murine liver tissue. The results demonstrate that all the biliary models expressed the IL-4Rα/IL-13Rα1 receptor complex. Incubation of cholangiocytes with either IL-13 or IL-4 increased the expression of TMEM16A protein, which was associated with an increase in the magnitude of Ca²⁺-activated Cl^- currents in response to ATP in single cells and the short-circuit current response in polarized monolayers. The IL-4- and IL-13-mediated increase in TMEM16A expression was also associated with an increase in STAT6 phosphorylation. Specific inhibition of JAK-3 inhibited the increase in TMEM16A expression and the IL-4-mediated increase in ATP-stimulated currents, whereas inhibition of STAT6 inhibited both IL-4- and IL-13-mediated increases in TMEM16A expression and ATP-stimulated secretion. These studies demonstrate that the cytokines IL-13 and IL-4 regulate the expression and function of biliary TMEM16A channels through a signaling pathway involving STAT6. Identification of this regulatory pathway provides new insight into biliary secretion and suggests new targets to enhance bile formation in the treatment of cholestatic liver disorders.NEW & NOTEWORTHY The Ca²⁺-activated Cl^- channel transmembrane member 16A (TMEM16A) has emerged as an important regulator of biliary secretion and hence, ductular bile formation. The present studies represent the initial description of the regulation of TMEM16A expression in biliary epithelium. Identification of this regulatory pathway involving the IL-4 and IL-13 receptor complex and JAK-3 and STAT-6 signaling provides new insight into biliary secretion and suggests new therapeutic targets to enhance bile formation in the treatment of cholestatic liver disorders.

Myocardin and myocardin-related transcription factor-A synergistically mediate actin cytoskeletal-dependent inhibition of liver fibrogenesis

Activation of hepatic stellate cells (HSCs), characterized by development of a robust actin cytoskeleton and expression of abundant extracellular matrix (ECM) proteins, such as type 1 collagen (COL.1), is a central cellular and molecular event in liver fibrosis. It has been demonstrated that HSCs express both myocardin and myocardin-related transcription factor-A (MRTF-A). However, the biological effects of myocardin and MRTF-A on HSC activation and liver fibrosis, as well as the molecular mechanism under the process, remain unclear. Here, we report that myocardin and MRTF-A's expression and nuclear accumulation are prominently increased during the HSC activation process, accompanied by robust activation of actin cytoskeleton dynamics. Targeting myocardin and MRTF-A binding and function with a novel small molecule, CCG-203971, led to dose-dependent inhibition of HSC actin cytoskeleton dynamics and abrogated multiple functional features of HSC activation (i.e., HSC contraction, migration and proliferation) and decreased COL.1 expression in vitro and liver fibrosis in vivo. Mechanistically, blocking the myocardin and MRTF-A nuclear translocation pathway with CCG-203971 directly inhibited myocardin/MRTF-A-mediated serum response factor (SRF), and Smad2/3 activation in the COL.1α2 promoter and indirectly abrogated actin cytoskeleton-dependent regulation of Smad2/3 and Erk1/2 phosphorylation and their nuclear accumulation. Finally, there was no effect of CCG-203971 on markers of inflammation, suggesting a direct effect of the compound on HSCs and liver fibrosis. These data reveal that myocardin and MRTF-A are two important cotranscriptional factors in HSCs and represent entirely novel therapeutic pathways that might be targeted to treat liver fibrosis.NEW & NOTEWORTHY Myocardin and myocardin-related transcription factor-A (MRTF-A) are upregulated in activated hepatic stellate cells (HSCs) in vitro and in vivo, closely associated with robustly increased actin cytoskeleton remodeling. Targeting myocardin and MRTF-A by CCG-203971 leads to actin cytoskeleton-dependent inhibition of HSC activation, reduced cell contractility, impeded cell migration and proliferation, and decreased COL.1 expression in vitro and in vivo. Dual expression of myocardin and MRTF-A in HSCs may represent novel therapeutic targets in liver fibrosis.

Hepatitis C eradication with direct-acting anti-virals reduces the risk of variceal bleeding

BACKGROUND

The real-world, long-term benefits of sustained virologic response (SVR) on the risk of variceal bleeding remain unclear.

AIM

To assess the association between DAA-induced SVR and post-treatment variceal bleeding METHODS: We identified patients who initiated DAA-only anti-viral treatments in the United States Veterans Affairs healthcare system from 2013 to 2015. We followed patients until 1 January 2019 for the development of gastro-oesophageal variceal bleeding defined by diagnostic codes. We used multivariable Cox proportional hazards regression to assess the association between SVR and development of variceal bleeding, adjusting for potential confounders.

RESULTS

Among 33 582 DAA-treated patients, 549 (1.6%) developed variceal bleeding after treatment (mean follow-up 3.1 years). Compared to no SVR, SVR was associated with a significantly lower incidence of variceal bleeding among all patients (0.46 vs 1.26 per 100 patient-years, adjusted hazard ratio [AHR] 0.66, 95% CI 0.52-0.83), among patients with pre-treatment cirrhosis (1.55 vs 2.96 per 100 patient-years, AHR 0.73, 95% CI 0.57-0.93) and among patients without pre-treatment cirrhosis (0.07 vs 0.29 per 100 patient-years, AHR 0.33, 95% CI 0.17-0.65). The risk of variceal bleeding after treatment was lower in those who achieved SVR vs no SVR among patients who had non-bleeding varices (3.5 vs 4.9 per 100 patient-years) or bleeding varices (12.9 vs 16.4 per 100 patient-years) diagnosed before treatment, but these differences were not statistically significant in adjusted analyses.

CONCLUSION

DAA-induced SVR is independently associated with a lower risk of variceal bleeding during long-term follow-up in patients with and without pre-treatment cirrhosis. These findings demonstrate an important real-world benefit of DAA treatment.

The Association of Abnormal Liver Tests with Hepatitis C Testing in Primary Care

BACKGROUND

As hepatitis C virus birth cohort (1945-1965) screening in primary care improves, testing patterns in response to persistently abnormal liver tests are less well known.

METHODS

This retrospective cohort study of a patient-centered medical home between 2007 and 2016 evaluates the association of abnormal liver chemistries and other clinical and demographic factors with hepatitis C antibody (HCV Ab) testing in patients with persistently abnormal liver tests. Patients with at least 2 consecutive abnormal liver tests were categorized by the clinical pattern of liver chemistry abnormality, including cholestatic, hepatocellular, and mixed patterns. The primary outcomes were: 1) completed HCV Ab tests; and 2) positive HCV Ab results for those patients tested.

RESULTS

Of 4512 patients with consecutive abnormal liver tests, only 730 (16%) underwent HCV Ab testing within 1 year of the second abnormality; 81/730 (11%) had HCV Ab detected. A logistic regression model revealed that mixed (odds ratio [OR] 2.20; 95% confidence interval [CI], 1.72-2.82) and hepatocellular (OR 1.43; 95% CI, 1.15-1.79) patterns of liver test abnormality, female sex, and alcohol and tobacco abuse were associated with higher odds of HCV Ab testing. Hepatocellular (OR 7.51; 95% CI, 2.18-25.94) and mixed patterns (OR 5.88; 95% CI, 1.64-21.15) of liver test abnormalities, male sex, Medicaid enrollment, and drug and tobacco abuse had higher odds of positive HCV Ab results.

CONCLUSIONS

There is opportunity to improve hepatitis C diagnostic testing in patients with consecutively elevated liver tests, and hepatocellular and mixed patterns of abnormality should prompt primary care providers to action.

Lower Gastrointestinal Bleeding in Patients With Cirrhosis-Etiology and Outcomes

BACKGROUND

Lower gastrointestinal bleeding (LGIB) is a common clinical problem, and may be more prevalent among patients with cirrhosis, especially in the setting of portal hypertension and coagulopathy. However, there is extremely little data available on the subject of LGIB in patients with cirrhosis. Therefore, the primary objective of this study was to better understand the etiology and outcomes of cirrhotic patients hospitalized with LGIB.

MATERIALS AND METHODS

We analyzed 3,735 cirrhotic patients admitted to the Medical University of South Carolina between January 2011 and September 2018, and identified patients admitted with a primary diagnosis of hematochezia or bright red blood per rectum.

RESULTS

Thirty patients with cirrhosis and LGIB were included in the cohort. The mean age was 56 ± 13 years, with 30% women. The mean model of end stage liver disease score was 22, and Child-Pugh (CP) scores were C: 41%, B: 33% and A: 26%. The mean Charlson Comorbidity Index was 5.6. Twenty-four (80%) patients had a clinical decompensating event (hepatic encephalopathy, ascites, esophageal varices); the mean hepatic venous pressure gradient was 14.1 mm Hg (n = 8). In 33% of patients, LGIB was considered significant bleeding that necessitated blood transfusion. The most common cause of LGIB was hemorrhoids (11 patients, 37%), followed by portal hypertensive enteropathy or colopathy (7 patients, 23%). Hemoglobin levels on admission were lower in patients with CP B/C cirrhosis than in those with CP A (P < 0.001). The length of stay was 9 ± 10 days, and 5 patients died (mortality, 17%).

CONCLUSIONS

Despite being uncommon, LGIB in cirrhotic patients is associated with a high mortality rate.

Aldehyde dehydrogenase-2 activation by Alda-1 decreases necrosis and fibrosis after bile duct ligation in mice

BACKGROUND AND AIM

Liver fibrosis is a leading cause of mortality worldwide. Oxidative stress is a key component in the pathogenesis of liver fibrosis. We investigated the role of aldehyde formation resulting from lipid peroxidation in cholestatic liver injury and fibrosis.

METHODS

C57Bl/6J mice underwent bile duct ligation (BDL) or sham operation. One hour after surgery and daily thereafter, animals were given Alda-1 (20 mg/kg, s.c.), an aldehyde dehydrogenase-2 activator, or equivalent volume of vehicle. Blood and livers were collected after 3 and 14 days.

RESULTS

Serum alanine aminotransferase (ALT) increased from 39.8 U/L after sham operation to 537 U/L 3 days after BDL, which Alda-1 decreased to 281 U/L. Biliary infarcts with a periportal distribution developed with an area of 7.8% at 14 days after BDL versus 0% area after sham operation. Alda-1 treatment with BDL decreased biliary infarcts to 1.9%. Fibrosis detected by picrosirius red staining increased from 1.6% area in sham to 7.3% after BDL, which decreased to 3.8% with Alda-1. Alda-1 suppression of fibrosis was additionally confirmed by second harmonic generation microscopy. After BDL, collagen-I mRNA increased 12-fold compared to sham, which decreased to 6-fold after Alda-1 treatment. Smooth muscle α-actin expression in the liver, a marker of activated stellate cells, increased from 1% area in sham to 18.7% after BDL, which decreased to 5.3% with Alda-1. CD68-positive macrophages increased from 33.4 cells/field in sham to 134.5 cells/field after BDL, which decreased to 64.9 cells/field with Alda-1. Lastly, 4-hydroxynonenal adduct (4-HNE) immunofluorescence increased from 2.5% area in sham to 14.1% after BDL. Alda-1 treatment decreased 4-HNE to 2.2%.

CONCLUSION

Accelerated aldehyde degradation by Alda-1 decreases BDL-induced liver necrosis, inflammation, and fibrosis, implying that aldehydes play an important role in the pathogenesis of cholestatic liver injury and fibrosis.

An Update: Portal Hypertensive Gastropathy and Colopathy

Complications of portal hypertension include portal hypertensive gastropathy and colopathy. These disorders may cause chronic or acute gastrointestinal bleeding. The diagnosis is made endoscopically; therefore, there is great variability in their assessment. Portal hypertensive gastropathy can range from a mosaic-like pattern resembling snakeskin mucosa to frankly bleeding petechial lesions. Portal hypertensive colopathy has been less well-described and is variably characterized (erythema, vascular lesions, petechiae). Treatment is challenging and results are inconsistent. Currently, available evidence does not support the use of beta-blockers for primary prevention. Further investigation of the pathogenesis, natural history, and treatment of these disorders is needed.

Smooth Muscle α-Actin Deficiency Leads to Decreased Liver Fibrosis via Impaired Cytoskeletal Signaling in Hepatic Stellate Cells

In the liver, smooth muscle α-actin (SM α-actin) is up-regulated in hepatic stellate cells (HSCs) as they transition to myofibroblasts during liver injury and the wound healing response. Whether SM α-actin has specific functional effects on cellular effectors of fibrosis such as HSC is controversial. Here, the relationship between SM α-actin and type 1 collagen expression (COL1A1), a major extracellular matrix protein important in liver fibrosis, is investigated with the results demonstrating that knockout of SM α-actin leads to reduced liver fibrosis and COL1 expression. The mechanism for the reduction in fibrogenesis in vivo is multifactorial, including not only a reduction in the number of HSCs, but also an HSC-specific reduction in COL1 expression in Acta2-deficient HSCs. Despite a compensatory increase in expression of cytoplasmic β-actin and γ-actin isoforms in Acta2^-/- HSCs, defects were identified in each transforming growth factor beta/Smad2/3 and ET-1/Erk1/2 signaling in Acta2^-/- HSCs. These data not only suggest a molecular link between the SM α-actin cytoskeleton and classic fibrogenic signaling cascades, but also emphasize the relationship between SM α-actin and fibrogenesis in hepatic myofibroblasts in vivo.

When Do Clinicians Follow-up Abnormal Liver Tests in Primary Care?

BACKGROUND

Many guidelines addressing the approach to abnormal liver chemistries, including bilirubin, transaminases and alkaline phosphatase, recommend repeating the tests. However, when clinicians repeat testing is unknown.

MATERIAL AND METHODS

This retrospective study followed adult patients with abnormal liver chemistries in a patient-centered medical home (PCMH) from 2007 to 2016. All PCMH patients possessing at least 1 abnormal liver test (total bilirubin, aminotransferases and alkaline phosphatase) were included. Patients were followed from the index abnormal liver chemistry until the next liver test result, or the end of the study period. The primary predictor variable of interest was the number of abnormal chemistries (out of 4) on index testing. Demographic and clinical variables served as other potential predictors of outcome. A Cox proportional hazards model was applied to investigate associations between the predictor variables and the time to repeat liver chemistry testing.

RESULTS

Of 9,545 patients with at least 2 PCMH visits and 1 liver test abnormality, 6,489 (68%) obtained repeat testing within 1 year, and 80% of patients had follow-up tests within 2 years. Patients with multiple abnormal liver tests and those with higher degrees of abnormality were associated with shorter time to repeat testing.

CONCLUSIONS

A large proportion of patients with abnormal liver tests still lack repeat testing at 1 year. The number of liver abnormal liver tests and degree of elevation were inversely associated with the time to repeat testing.

Prioritization of Therapeutic Targets and Trial Design in Cirrhotic Portal Hypertension

Portal hypertension (PH) is the main driver of cirrhosis decompensation, the main determinant of death in patients with cirrhosis. PH results initially from increased intrahepatic vascular resistance. Subsequently, increased inflow from splanchnic vasodilation and increased cardiac output lead to a further increase in portal pressure (PP). Reducing PP in cirrhosis results in better outcomes. Removing the cause of cirrhosis might improve PP. However, this is a slow process and patients may continue to be at risk of decompensation. Additionally, for some chronic liver diseases, such as nonalcoholic fatty liver disease (NAFLD), etiological treatments are not yet available. Therefore, there is a need to develop better therapies specifically aimed at reducing PP. For over 35 years, the mainstay of such therapy has been the use of nonselective beta-blockers (NSBBs) that act by reducing portal venous inflow. Recently, many drugs (mainly targeting intrahepatic mechanisms) have shown promise in preclinical and early clinical studies and may act alone or synergistically with NSBBs in reducing PP in cirrhosis. The objective of this position paper is to propose a novel framework for the design of clinical trials (phase 1, 2, and 3) in patients with cirrhosis and PH and to prioritize targets and pharmacological therapies in this setting. We have focused the discussion on patients with compensated cirrhosis. The paper summarizes discussions held at The American Association for the Study of Liver Diseases (AASLD) Industry Colloquium in January 2018, with the participation of clinical and translational investigators, regulatory professionals, and industry partners.

Hepatic stellate cells retain retinoid-laden lipid droplets after cellular transdifferentiation into activated myofibroblasts

Loss of retinyl ester (RE)-rich lipid droplets (LDs) from hepatic stellate cells (HSCs) is cited as a key event in their cellular transdifferentiation to activated, pro-fibrotic myofibroblasts; however, it remains unclear if changes in LD morphology or RE content are causal for transdifferentiation. To better understand LD dynamics in vitro within a common model of HSC activation, we used novel approaches preserving LD morphology and allowing for quantitation of RE. The size and quantity of LDs within in vitro and in vivo bile duct ligation (BDL)-activated HSCs were quantitated using adipocyte differentiation-related protein (ADRP) labeling and oil red o (ORO) staining (gold standard), and RE content was determined using fluorescence microscopy. We found during HSC activation in vitro that LD number differed significantly when measured by ADRP and ORO, respectively ( day 1: 56 vs. 5, P = 0.03; day 4: 101 vs. 39, P = 0.03; day 14: 241 vs. 12, P = 0.02). Ex vivo HSCs activated in vivo contained the same number of LDs as day 4 in vitro activated HSCs (118 vs. 101, P = 0.54). Decline in LD RE occurred beyond day 4 in vitro and day 1 ex vivo , after HSC transdifferentiation was underway. Lastly, in situ HSCs examined using electron microscopy show LDs tend to be smaller but are ultimately retained in BDL injured livers. Therefore, we conclude that during HSC transdifferentiation, LDs are not lost but are retained, decreasing in size. Additionally, RE content declines after transdifferentiation is underway. These data suggest that these LD changes are not causal for HSC transdifferentiation. NEW & NOTEWORTHY Loss of retinoid-laden lipid droplets from hepatic stellate cells has long been held as a hallmark of their transdifferentiation into activated myofibroblasts, the dominant cells that drive hepatic fibrosis. This study demonstrates that stellate cells activated in culture and after liver injury in vivo retain their lipid droplets and that these droplets become smaller and more numerous, with decreases in droplet retinoid concentration occurring only after cellular transdifferentiation is underway.

Identification and Management of the Hypervirulent Invasive Klebsiella pneumoniae Syndrome: A Unique and Distinct Clinical Entity

In this article, we describe the case of a 61-year-old woman who presented with altered mental status and was found to have Klebsiella pneumoniae meningitis, bacteremia, and hepatic abscess. Despite intravenous antibiotic therapy and percutaneous drainage of the hepatic abscess, the patient developed worsening meningitis with ventriculitis, which led to her death. This invasive Klebsiella syndrome is characterized by metastatic infections with a hypervirulent strain and a poor clinical prognosis. Important elements of this patient’s case—including the widespread and highly aggressive course—and of those reported in the literature are reviewed. Although the invasive Klebsiella syndrome is an increasingly recognized clinical entity, most often in the Eastern hemisphere, it remains rare in the United States with approximately 20 cases reported in the literature, and given its high morbidity, it is vitally important for clinicians to recognize.