AXL expression on homeostatic resident liver macrophages is reduced in cirrhosis following GAS6 production by hepatic stellate cells

BACKGROUND & AIMS

AXL and MERTK expression on circulating monocytes modulated immune responses in patients with cirrhosis (CD14⁺HLA-DR⁺AXL⁺) and acute-on-chronic liver failure (CD14⁺MERTK⁺). AXL expression involved enhanced efferocytosis, sustained phagocytosis, but reduced TNF-α/IL-6 production and T cell activation, suggesting a homeostatic function. Axl was expressed on murine airway in tissues contacting the external environment- but not interstitial lung-, and tissue-resident synovial lining macrophages. We assessed AXL expression on tissue macrophages in patients with cirrhosis.

METHODS

Using multiplexed immunofluorescence we compared AXL expression in liver biopsies in cirrhosis (n=22), chronic liver disease (n=8), non-cirrhotic portal hypertension (n=4) and healthy controls (n=4). Phenotype and function of isolated primary human liver macrophages were characterised by flow cytometry (cirrhosis, n=11; control, n=14) ex vivo. Also, AXL expression was assessed on peritoneal- (n=29) and gut macrophages (n=16) from cirrhotic patients. Regulation of AXL expression was analysed in vitro and ex vivo using primary hepatic stellate cells (HSCs), LX-2 cells and GAS6 in co-culture experiments.

RESULTS

AXL was expressed on resident (CD68⁺) but not tissue-infiltrating (MAC387⁺) liver macrophages, hepatocytes, HSCs, or sinusoidal endothelial cells. Prevalence of hepatic CD68⁺AXL⁺ cells significantly decreased with cirrhosis progression: (Healthy 90.2%; Child Pugh A 76.1%; B 64.5%; C 18.7%, all p<0.05) and negatively correlated with MELD and CRP (all p<0.05). AXL-expressing hepatic macrophages were CD68^highHLA-DR^highCD16^highCD206^high. AXL expression also decreased on gut and peritoneal macrophages from cirrhotic patients, but increased in regional lymph nodes. GAS6, enriched in the cirrhotic liver, appeared to be secreted by HSCs and down-regulate AXL in vitro.

CONCLUSIONS

Decreased AXL expression on resident liver macrophages in advanced cirrhosis, potentially in response to activated HSCs-secreted GAS6, suggests a role for AXL in the regulation of hepatic immune homeostasis.

Patient-derived tumor organoids for personalized medicine in a patient with rare hepatocellular carcinoma with neuroendocrine differentiation: a case report

Background

Hepatocellular carcinoma with neuroendocrine differentiation (HCC-NED) is a very rare subtype of primary liver cancer. Treatment allocation in these patients therefore remains a challenge.

Methods

We report the case of a 74-year-old man with a HCC-NED. The tumor was surgically removed in curative intent. Histopathological work-up revealed poorly differentiated hepatocellular carcinoma (Edmondson-Steiner grade IV) with diffuse expression of neuroendocrine markers synaptophysin and chromogranin. Three months after resection, multifocal recurrence of the HCC-NED was observed. In the meantime, tumor organoids have been generated from the resected HCC-NED and extensively characterized. Sensitivity to a number of drugs approved for the treatment of HCC or neuroendocrine carcinomas was tested in vitro.

Results

Based on the results of the in vitro drug screening, etoposide and carboplatin are used as first line palliative combination treatment. With genomic analysis revealing a NTRK1-mutation of unknown significance (kinase domain) and tumor organoids found to be sensitive to entrectinib, a pan-TRK inhibitor, the patient was treated with entrectinib as second line therapy. After only two weeks, treatment is discontinued due to deterioration of the patient’s general condition.

Conclusion

The rapid establishment of patient-derived tumor organoids allows in vitro drug testing and thereby personalized treatment choices, however clinical translation remains a challenge. To the best of our knowledge, this report provides a first proof-of-principle for using organoids for personalized medicine in this rare subtype of primary liver cancer.

Tumors that simultaneously display features of liver, nerve and hormone-producing cells are very rare. In such cases, the most appropriate treatment choice is not well defined. Here, we describe the generation of three-dimensional miniature tumors, called organoids, from the patient’s tumor tissue, that can be grown and studied in a culture dish. These organoids closely mimic the patient’s tumor and allowed us to test different drugs to identify the most effective therapy for informed treatment choice. What we describe in this study is an emerging approach for a practice known as personalized medicine, that aims to provide a more tailored treatment to patients. In summary, we demonstrate that this approach can be useful in a rare cancer type and that it holds significant potential to guide treatment decision in other patients with aggressive cancers.

Meier, Nuciforo, Coto-Llerena et al. report a rare case of a patient with hepatocellular carcinoma with neuroendocrine differentiation. The authors establish organoids that recapitulate the genetic features of the patient’s tumor and are used for ex vivo drug testing to guide therapy selection in the patient.

Stimulatory MAIT cell antigens reach the circulation and are efficiently metabolised and presented by human liver cells

OBJECTIVE

Mucosal-associated invariant T (MAIT) cells are the most abundant T cells in human liver. They respond to bacterial metabolites presented by major histocompatibility complex-like molecule MR1. MAIT cells exert regulatory and antimicrobial functions and are implicated in liver fibrogenesis. It is not well understood which liver cells function as antigen (Ag)-presenting cells for MAIT cells, and under which conditions stimulatory Ags reach the circulation.

DESIGN

We used different types of primary human liver cells in Ag-presentation assays to blood-derived and liver-derived MAIT cells. We assessed MAIT cell stimulatory potential of serum from healthy subjects and patients with portal hypertension undergoing transjugular intrahepatic portosystemic shunt stent, and patients with inflammatory bowel disease (IBD).

RESULTS

MAIT cells were dispersed throughout healthy human liver and all tested liver cell types stimulated MAIT cells, hepatocytes being most efficient. MAIT cell activation by liver cells occurred in response to bacterial lysate and pure Ag, and was prevented by non-activating MR1 ligands. Serum derived from peripheral and portal blood, and from patients with IBD stimulated MAIT cells in MR1-dependent manner.

CONCLUSION

Our findings reveal previously unrecognised roles of liver cells in Ag metabolism and activation of MAIT cells, repression of which creates an opportunity to design antifibrotic therapies. The presence of MAIT cell stimulatory Ags in serum rationalises the observed activated MAIT cell phenotype in liver. Increased serum levels of gut-derived MAIT cell stimulatory ligands in patients with impaired intestinal barrier function indicate that intrahepatic Ag-presentation may represent an important step in the development of liver disease.

Circulating Cell-Free DNA Captures the Intratumor Heterogeneity in Multinodular Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly heterogeneous disease, with more than 40% of patients initially diagnosed with multinodular HCCs. Although circulating cell-free DNA (cfDNA) has been shown to effectively detect somatic mutations, little is known about its utility to capture intratumor heterogeneity in patients with multinodular HCC undergoing systemic treatment.

Genomic analysis of focal nodular hyperplasia with associated hepatocellular carcinoma unveils its malignant potential: a case report

Background

Focal nodular hyperplasia (FNH) is typically considered a benign tumor of the liver without malignant potential. The co-occurrence of FNH and hepatocellular carcinoma (HCC) has been reported in rare cases. In this study we sought to investigate the clonal relationship between these lesions in a patient with FNH-HCC co-occurrence.

Methods

A 74-year-old female patient underwent liver tumor resection. The resected nodule was subjected to histologic analyses using hematoxylin and eosin stain and immunohistochemistry. DNA extracted from microdissected FNH and HCC regions was subjected to whole exome sequencing. Clonality analysis were performed using PyClone.

Results

Histologic analysis reveals that the nodule consists of an FNH and two adjoining HCC components with distinct histopathological features. Immunophenotypic characterization and genomic analyses suggest that the FNH is clonally related to the HCC components, and is composed of multiple clones at diagnosis, that are likely to have progressed to HCC through clonal selection and/or the acquisition of additional genetic events.

Conclusion

To the best of our knowledge, our work is the first study showing a clonal relationship between FNH and HCC. We show that FNH may possess the capability to undergo malignant transformation and to progress to HCC in very rare cases.

Epigenetic priming in chronic liver disease impacts the transcriptional and genetic landscapes of hepatocellular carcinoma

Hepatocellular carcinomas (HCCs) usually arise from chronic liver disease (CLD). Precancerous cells in chronically inflamed environments may be 'epigenetically primed', sensitising them to oncogenic transformation. We investigated whether epigenetic priming in CLD may affect HCC outcomes by influencing the genomic and transcriptomic landscapes of HCC. Analysis of DNA methylation arrays from 10 paired CLD-HCC identified 339 shared dysregulated CpG sites and 18 shared differentially methylated regions compared with healthy livers. These regions were associated with dysregulated expression of genes with relevance in HCC, including ubiquitin D (UBD), cytochrome P450 family 2 subfamily C member 19 (CYP2C19) and O-6-methylguanine-DNA methyltransferase (MGMT). Methylation changes were recapitulated in an independent cohort of nine paired CLD-HCC. High CLD methylation score, defined using the 124 dysregulated CpGs in CLD and HCC in both cohorts, was associated with poor survival, increased somatic genetic alterations and TP53 mutations in two independent HCC cohorts. Oncogenic transcriptional and methylation dysregulation is evident in CLD and compounded in HCC. Epigenetic priming in CLD sculpts the transcriptional landscape of HCC and creates an environment favouring the acquisition of genetic alterations, suggesting that the extent of epigenetic priming in CLD could influence disease outcome.

Ubiquitous expression of HBsAg from integrated HBV DNA in patients with low viral load

BACKGROUND & AIMS

Loss of serum HBsAg is a hallmark of spontaneous and therapy induced resolution of HBV infection, since it generally reflects a profound decrease in viral replication. However, integrated HBV DNA can contribute to HBsAg expression independent of viral replication. The relative contributions of these sources of HBsAg are not well understood. Specifically, it is not known whether actively transcribed HBV integration could spread throughout the entire liver.

METHODS

The relative distribution of HBsAg and HBV RNA in liver biopsy tissue from HBeAg-negative (HBe^-) patients was analyzed by immunohistochemistry and in situ hybridization (ISH), respectively. Frozen biopsy tissue was used for molecular analysis of intrahepatic viral RNA, virus-host chimeric transcripts and viral DNA.

RESULTS

Immunohistochemistry and ISH analysis revealed HBsAg and HBV RNA positivity in virtually all hepatocytes in the liver of some HBe^- patients despite very low viremia. Reverse transcription quantitative PCR and RNA-sequencing analysis confirmed high expression levels of HBV envelope-encoding RNAs. However, the amount of viral transcriptional template (covalently closed circular (ccc)DNA) was too low to support this ubiquitous HBV RNA expression. In contrast, levels of total cellular HBV DNA were consistent with ubiquitous HBV integration. Finally, RNA-sequencing revealed the presence of many HBV-host chimeric transcripts with the potential for HBsAg expression.

CONCLUSIONS

Transcriptionally active HBV integration can extend to the entire liver in some HBe^- patients. This can lead to ubiquitous HBsAg expression independent of HBV replication. In such patients, HBsAg is probably not a clinically useful surrogate marker for viral resolution or functional cure.

LAY SUMMARY

Loss of serum hepatitis B surface antigen (HBsAg) indicates resolution of HBV infection. However, integrated HBV DNA can contribute to HBsAg production independently of viral replication. We investigated the extent of HBsAg-producing viral integration in the livers of patients with low serum viral loads. Our findings suggest that transcriptionally active HBV integration can extend to the entire liver in some patients, questioning the clinical utility of HBsAg as a surrogate marker for viral replication.

Transition to HBeAg-negative chronic hepatitis B virus infection is associated with reduced cccDNA transcriptional activity

BACKGROUND & AIMS

HBeAg seroconversion during the natural history of chronic hepatitis B (CHB) is associated with a strong drop in serum HBV DNA levels and a reduction of intrahepatic covalently closed circular DNA (cccDNA) content. Of particular interest is the transition to HBeAg-negative chronic infection (ENCI). ENCI, previously known as inactive carrier state, is characterized by very low or negative viremia and the absence of liver disease. The molecular mechanisms responsible for the transition to ENCI and for the control of viral replication in ENCI are still poorly understood.

METHODS

To identify which step(s) in the viral life cycle are controlled during the transition to ENCI, we quantified cccDNA, pre-genomic RNA (pgRNA), total HBV RNA and DNA replicative intermediates in 68 biopsies from patients in different phases of CHB.

RESULTS

HBeAg seroconversion is associated with a reduction of cccDNA amounts as well as transcriptional activity. Silencing of cccDNA is particularly pronounced in ENCI, where there was ~46 times less pgRNA per cccDNA compared to HBeAg-negative CHB. Furthermore, a subgroup of patients with HBeAg-negative CHB can be characterized by reduced replication efficiency downstream of pgRNA.

CONCLUSIONS

The reduction in serum viral load during the transition to ENCI seems to primarily result from strong inhibition of the transcriptional activity of cccDNA which can be maintained in the absence of liver disease.

LAY SUMMARY

During the natural course of chronic hepatitis B virus infections, the immune response can gain control of viral replication. Quantification of viral DNA and RNA in liver biopsies of patients in different stages of chronic hepatitis B allowed us to identify the steps in the viral life cycle that are affected during the transition from active to inactive disease. Therapeutic targeting of these steps might induce sustained inhibition of viral transcription.

Adiabatic electron thermal pressure fluctuations in tokamak plasmas

Electron thermal pressure fluctuations measured in the edge plasma of the Texas Experimental Tokamak Upgrade are a fundamental component of plasma turbulence on both sides of the velocity shear layer. The ratio of specific heats, estimated from fluctuations in electron temperature and electron number density measured simultaneously at the same electrode, indicates that observed fluctuations are adiabatic. The observations are made by means of a novel Langmuir probe technique, the time domain triple-probe method, which concurrently measures multiple plasma properties at each of two electrodes with the temporal and the spatial resolution required to estimate thermodynamic properties in a turbulent plasma.

[Coronary fistula associated with severe pulmonary stenosis and cianosis]

A 17 year old male adolescent was admitted to the hospital due to dyspnea and cyanosis, since the age of 6 years. On physical examination, it was found a continuous murmur over the left esternal border at the 4th and 5th intercostal spaces suggesting a coronary fistula. A color-echocardiogram associated with an angiography confirmed the diagnosis of coronary fistula and severe pulmonary stenosis. The functional consequence was a right to left shunt with cyanosis. A surgical repair was performed with closure of the fistula at the point where it drained into the right ventricle plus a pulmonary commissurotomy. The patient had an uneventful recovery.

[Surgical treatment of high-risk valvar endocarditis]

The authors have studied the immediate and long term outcome of surgical treatment of acute phase infective endocarditis in a group of 33 high risk patients with valvular heart disease. The age varied from 2 to 68 years, 18 patients were male and 22 were of the white race. The aortic valve was the most frequently involved (18/54.5%), followed by mitral valve (13/39.3%), and tricuspid valve (2/6.0%). Twenty-four patients (72.7%) were in functional class III and seven (21.0%) in functional class IV. The noninvasive studies in those patients revealed 13 cases (39.4%) with normal cardiac size. The EKG was abnormal in 27 cases (81.8%) mostly with left atrial and ventricular hypertrophy. The echocardiogram revealed the presence of vegetations in 27 patients (81.8%) and the blood cultures were positive in 24 cases (72.7%). All patients were treated with antibiotics. The pathologic analysis revealed the presence of vegetations in 94% and structural alterations in 16.5%. Twenty-one patients had heart valve replacement with mechanical prosthesis (63.6%), 11 (33.3%) had bioprosthesis and one had tricuspid excision without replacement (3.0%). The hospital mortality was 12% and the late mortality 3%. Three deaths occurred in patients who had prolonged clinical treatment (more than 35 days) and one patient died of severe fungal endocarditis. The follow-up of the remaining 26 patients varied from 1 to 596 weeks (mean 183) demonstrating important clinical improvement and a normally functioning valve prosthesis. All patients remained in functional class I or II. The analysis of our data indicates that surgical treatment is the best option for high risk endocarditis and should be undertaken earlier in all patients in this group.

[Surgical treatment of high-risk valvular endocarditis]

The authors have studied the short and long term results of surgical treatment of acute phase of infectious endocarditis in a group of 33 high risk patients with valvular heart disease. The age varied from 2 to 68 years; 18 patients were male and 22 were of the white race. The aortic valve was most frequently involved (18/54.5%), followed by the mitral valve (13/39.3%) and tricuspid valve (2/6.0%). Twenty four patients (72.7%) were in functional class III and seven (21%) in functional class IV. The noninvasive studies in those patients revealed 13 cases (39.4%) with normal cardiac size. The ECG was abnormal in 27 cases (81.8%) mostly with left atrial and ventricular hypertrophy. The echocardiogram revealed the presence of vegetations in 27 patients (81.8%) and blood cultures were positive in 22 cases (66.6%). All patients were treated with antibiotics. The pathologic analysis revealed the presence of vegetations in 94% and structural alterations in 16.5%. Twenty-one patients had heart valve replacement with mechanical prosthesis (63.6%), 11(33.3%) had bioprosthesis and one had tricuspid excision without replacement (3.0%). The hospital mortality was 12% and the late mortality 3%. Three deaths occurred in patients who had prolonged clinical treatment (more than 65 days) and one patient died of severe fungal endocarditis. The follow-up of the remaining 26 patients varied from 01 to 448 weeks (mean 183) demonstrating important clinical improvement and a normally functioning valve prostheses. All patients are in functional class I and II. The analysis of our data indicates that surgical treatments is the best option for high risk endocarditis and should be undertaken earlier in all patients in this risk group.

A new technique for repair of mitral insufficiency caused by ruptured chordae of the anterior leaflet

Prolapse of the anterior leaflet of the mitral valve is the result of ruptured chordae, elongated chordae, or elongated or ruptured papillary muscle. Several techniques have been described for the correction of mitral valve insufficiency. However, when there is severe rupture of the chordae, the most widely accepted solution is valve replacement. We describe a technique for the creation of a neochorda with a strip of tissue from the anterior leaflet of the mitral valve. This technique was used in two patients with severe mitral valve regurgitation. Formation of a neochorda and placement of a Carpentier ring to remodel the anulus obviated the need for a valve replacement. Both patients had an uneventful recovery. Studies performed 3 and 4 months postoperatively showed competent and well-functioning valves. One patient required a valve replacement for acute mitral insufficiency 5 years later, but the other patient was doing well 3 years after the operation. Despite the limited experience, we believe this technique offers a reasonable alternative to valve replacement.

A new technique for repair of aortic coarctation. Subclavian flap aortoplasty with preservation of arterial blood flow to the left arm

From February 1984 to March 1986, 28 patients underwent a new technique of coarctation repair. This technique consists of a complete mobilization of the left subclavian artery extended to the origin of its first branches. The aorta need not be extensively mobilized and the intercostal arteries are individually controlled with snares. After all the proper clamping, the left subclavian artery is detached from the aorta at its origin and is opened longitudinally on its posterior aspect. The anterior wall of the aorta is then incised, beginning with the opening at the origin of the left subclavian artery and extending distally to the descending aorta 12 to 15 mm past the coarctation. The coarctation membrane is excised and the ductus is ligated and divided. The opened left subclavian artery, now forming a flap, is pulled down and sutured to the edges of the aorta, widening the coarctation site and also preserving the blood flow to the left arm. The ages of the patients ranged from 2 months to 25 years (mean 4.24 +/- 4.9 years) and their weights ranged from 2.8 to 52 kg (mean: 14.8 +/- 10.0 kg). There were no hospital deaths and the mean follow-up was 9.6 months (+/- 4.9 months). Recatheterization of four patients from 4 to 12 months postoperatively showed adequate correction and strongly suggested normal growth of the aorta at the site of coarctation, as well as preservation of the blood flow through the left subclavian artery. Doppler measurements showed normal flow to the left arm and no gradients through the isthmic area. Our experience indicates that this technique is not only feasible but is the procedure of choice in most cases of discrete isthmic coarctation and in some cases of long narrowing of the isthmus in patients with a wide range of ages and weights.

Molecular epidemiology of antibiotic resistance plasmids of Haemophilus species and Neisseria gonorrhoeae

Ampicillin resistance in Haemophilus influenzae and Neisseria gonorrhoeae is most commonly due to plasmid-mediated production of the TEM beta-lactamase. The H. influenzae plasmids may have evolved by insertion of various antibiotic resistance transposons into a phenotypically cryptic plasmid found in one of 699 isolates of H. influenzae examined. The small, nonconjugative, beta-lactamase-specifying plasmids of N. gonorrhoeae and Haemophilus species are highly related. Phenotypically cryptic plasmids found in several epidemiologically distinct isolates of Haemophilus parainfluenzae are highly related to the beta-lactamase plasmids but carry no transposon A (TnA) sequences. This evidence strongly favors the hypothesis that the beta-lactamase plasmids evolved by the insertion of TnA (possibly introduced from enteric bacteria) into cryptic plasmids resident in H. parainfluenzae.

Interruption of double inferior vena cava for prevention of pulmonary embolism

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