Quantitative histological-hemodynamic correlations in cirrhosis

qFibrosis: a fully-quantitative innovative method incorporating histological features to facilitate accurate fibrosis scoring in animal model and chronic hepatitis B patients

BACKGROUND & AIMS

There is increasing need for accurate assessment of liver fibrosis/cirrhosis. We aimed to develop qFibrosis, a fully-automated assessment method combining quantification of histopathological architectural features, to address unmet needs in core biopsy evaluation of fibrosis in chronic hepatitis B (CHB) patients.

METHODS

qFibrosis was established as a combined index based on 87 parameters of architectural features. Images acquired from 25 Thioacetamide-treated rat samples and 162 CHB core biopsies were used to train and test qFibrosis and to demonstrate its reproducibility. qFibrosis scoring was analyzed employing Metavir and Ishak fibrosis staging as standard references, and collagen proportionate area (CPA) measurement for comparison.

RESULTS

qFibrosis faithfully and reliably recapitulates Metavir fibrosis scores, as it can identify differences between all stages in both animal samples (p<0.001) and human biopsies (p<0.05). It is robust to sampling size, allowing for discrimination of different stages in samples of different sizes (area under the curve (AUC): 0.93-0.99 for animal samples: 1-16 mm(2); AUC: 0.84-0.97 for biopsies: 10-44 mm in length). qFibrosis can significantly predict staging underestimation in suboptimal biopsies (<15 mm) and under- and over-scoring by different pathologists (p<0.001). qFibrosis can also differentiate between Ishak stages 5 and 6 (AUC: 0.73, p=0.008), suggesting the possibility of monitoring intra-stage cirrhosis changes. Best of all, qFibrosis demonstrates superior performance to CPA on all counts.

CONCLUSIONS

qFibrosis can improve fibrosis scoring accuracy and throughput, thus allowing for reproducible and reliable analysis of efficacies of anti-fibrotic therapies in clinical research and practice.

Role of magnetic resonance elastography in compensated and decompensated liver disease

BACKGROUND & AIMS

Non-invasive predictors identifying subjects with compensated liver disease at highest risk for transitioning to a decompensated state are lacking. We hypothesized that liver shear stiffness as measured by magnetic resonance elastography is an important non-invasive predictor of hepatic decompensation.

METHODS

Among patients with advanced fibrosis undergoing magnetic resonance elastography (2007-2011), a baseline cohort and follow up cohort (compensated liver disease) were established. Cause specific cox proportional hazards analysis adjusting for competing risks was utilized to determine the association between elevated liver shear stiffness and development of decompensation (hepatic encephalopathy, ascites, variceal bleeding).

RESULTS

In the baseline cohort (n=430), subjects with decompensated liver disease had a significantly higher mean liver shear stiffness (6.8kPa, IQR 4.9-8.5) as compared to subjects with compensated liver disease (5.2kPa, IQR 4.1-6.8). After adjustment for Model for End Stage Liver Disease score, hepatitis C, age, gender, albumin, and platelet count, the mean liver shear stiffness (OR=1.13, 95% CI 1.03-1.27) was independently associated with decompensated cirrhosis at baseline. Over a median follow up of 27months (n=167), 7.2% of subjects with compensated disease experienced hepatic decompensation. In the follow up cohort, the hazard of hepatic decompensation was 1.42 (95% CI 1.16-1.75) per unit increase in liver shear stiffness over time. The hazard of hepatic decompensation was 4.96 (95% CI 1.4-17.0, p=0.019) for a subject with compensated disease and mean LSS value ⩾5.8kPa as compared to an individual with compensated disease and lower mean LSS values.

CONCLUSION

Baseline liver shear stiffness assessed by magnetic resonance elastography is independently associated with decompensated liver disease.

Collagen proportionate area is superior to other histological methods for sub-classifying cirrhosis and determining prognosis

BACKGROUND & AIMS

One-year survival in cirrhosis ranges from 1 to 57% depending on the clinical stage. Accurate sub-classification has important prognostic implications but there is no stage beyond cirrhosis using current qualitative histological systems. We compared the performance of all histological semi-quantitative and quantitative methods specifically developed for sub-classifying cirrhosis that have been described to date, with collagen proportionate area (CPA), to evaluate how well they distinguish patients with and without hepatic clinical decompensation at presentation, and in predicting future decompensating events.

METHODS

We included consecutive patients with a histological diagnosis of cirrhosis that had a suitable liver biopsy between 2003 and 2007. We used semi-quantitative histological scoring systems proposed by Laennec, Kumar, and Nagula. We also measured quantitatively nodule size, septal width and fibrous tissue expressed in CPA.

RESULTS

Sixty-nine patients, mean age 52.3±11years, mean MELD 11.8±5.8, median follow-up 56months. Main aetiologies were alcohol (38%) and hepatitis C (27.5%). Twenty-four patients (34.8%) had had a previous episode of clinical decompensation. Amongst the 45 patients who were compensated, 11 (24%) decompensated on follow-up. In Cox regression, amongst all histological parameters, CPA was the only variable independently associated with clinical decompensation up to the time of biopsy, with an odds ratio that ranged from 1.245 to 1.292. Furthermore, only CPA was significantly associated with future decompensation (OR: 1.117, 95% CI 1.020-1.223; p=0.017).

CONCLUSIONS

Cirrhosis can be accurately sub-classified using quantification of fibrosis with CPA, and furthermore CPA is the only independent predictor of clinical decompensation amongst all other histological sub-classification systems described to date.

Beyond a broken heart: circulatory dysfunction in the failing Fontan

The role of ventricular dysfunction in late morbidity and mortality of univentricular hearts has been described previously. However, a significant proportion of adult Fontan patients who die or require heart transplantation do so with preserved ventricular function. The clinical deterioration in patients who have undergone Fontan palliation requires a broader view of circulatory dysfunction, one that takes into account the complex interaction of regulatory systems affecting hepatic, renal, and pulmonary blood flow, in addition to cardiac function. This review focuses primarily on the pathophysiology of multiple organ involvement in this circulatory dysfunction, with particular focus on the consequences of hepatic dysfunction and portal hypertension. The authors discuss hepatic perfusion, both in health and disease, and review the current understanding of liver histopathology and liver disease in adult Fontan patients and similar clinicopathologic states. They compare and contrast features of postsinusoidal portal hypertension with more typical adult cirrhotic disease. Finally, they delineate the related effects of portal hypertensive physiology on the systemic and pulmonary vasculature, the kidney, and the heart itself and discuss how these changes affect the care of the adult Fontan patient.

Hydrogels with differential and patterned mechanics to study stiffness-mediated myofibroblastic differentiation of hepatic stellate cells

The differentiation of hepatic stellate cells (HSCs) into myofibroblasts is a key event in liver fibrosis. Due to the local stiffening of the extracellular matrix (ECM) during fibrosis, it is of great interest to develop mimics that can be used to investigate the cellular response to changes in mechanics. Here, we used a step-wise hydrogel crosslinking technique, where macromolecules are crosslinked using a sequence of addition then UV light-mediated radical crosslinking, to generate hydrogels with tunable stiffness. Freshly isolated HSCs remained rounded with lipid droplets and high levels of PPARγ expression on soft substrates (E~2kPa); however, HSCs spread, lost their lipid droplets, and expressed high levels of α-smooth muscle actin (α-SMA) and type I collagen on stiff substrates (E~24kPa). Similarly, fully differentiated cells reverted to a quiescent state when plated on soft substrates. Stiffness-induced differentiation of HSCs was enhanced in the presence of exogenous TGF-β1, a dominant signal in fibrosis. When the UV-induced secondary crosslinking was restricted with a photomask to spatially control mechanics, HSCs responded based on the local hydrogel stiffness, although they remained quiescent on stiff substrates if the stiff feature size was not sufficient to allow cell spreading. This hydrogel system permits the investigation of HSC response to materials with diverse levels and spatially heterogeneous mechanical properties.

Image analysis of liver collagen using sirius red is more accurate and correlates better with serum fibrosis markers than trichrome

BACKGROUND

Collagen proportional area (CPA) determined by quantitative digital image analysis better quantifies liver fibrosis than histological stage; however, its clinical use has been limited by non-standardized methods.

AIM

This study aimed to compare CPA obtained using different staining methods, magnifications and biopsy sizes.

METHODS

Two hundred and forty-nine patients with chronic hepatitis C who had a liver biopsy and serum fibrosis markers performed were included. CPA was measured either using a sirius red (CPAs) or a trichrome (CPAt) stain.

RESULTS

CPAs measured at 20× and 40× magnifications generated similar outcomes with interclass correlation (ICC) coefficient of 0.98. Compared with trichrome, sirius red staining had much less variation with an ICC coefficient of 0.99 for slides stained in the same batch and 0.92 in different batches. Mean CPAs was higher than mean CPAt by 3.53%, P < 0.001. Morphological analysis found that sirius red detected delicate fibrous septa and spurs better than trichrome. Both CPAs and CPAt correlated well with Metavir stage, whereas CPAs had better ability to detect cirrhosis with the area under ROC curve of 0.95. Overall CPA had superior correlation with serum markers of fibrosis in Metavir F2-F4 than that in F0-F1 and CPAs correlated better with serum fibrosis markers than CPAt in Metavir F0-F1. Multivairate analysis found that HA, α2-macroglobulin, platelet count and albumin were independently correlated with CPAs and only HA was independently correlated with CPAt.

CONCLUSIONS

Sirius red staining for CPA determination was more accurate and reliable for quantifying hepatic collagen compared with trichrome staining.

Regional metabolic liver function measured in patients with cirrhosis by 2-[¹⁸F]fluoro-2-deoxy-D-galactose PET/CT

BACKGROUND & AIMS

There is a clinical need for methods that can quantify regional hepatic function non-invasively in patients with cirrhosis. Here we validate the use of 2-[(18)F]fluoro-2-deoxy-d-galactose (FDGal) PET/CT for measuring regional metabolic function to this purpose, and apply the method to test the hypothesis of increased intrahepatic metabolic heterogeneity in cirrhosis.

METHODS

Nine cirrhotic patients underwent dynamic liver FDGal PET/CT with blood samples from a radial artery and a liver vein. Hepatic blood flow was measured by indocyanine green infusion/Fick's principle. From blood measurements, hepatic systemic clearance (Ksyst, Lblood/min) and hepatic intrinsic clearance (Vmax/Km, Lblood/min) of FDGal were calculated. From PET data, hepatic systemic clearance of FDGal in liver parenchyma (Kmet, mL blood/mL liver tissue/min) was calculated. Intrahepatic metabolic heterogeneity was evaluated in terms of coefficient-of-variation (CoV, %) using parametric images of Kmet.

RESULTS

Mean approximation of Ksyst to Vmax/Km was 86% which validates the use of FDGal as PET tracer of hepatic metabolic function. Mean Kmet was 0.157 mL blood/mL liver tissue/min, which was lower than 0.274 mL blood/mL liver tissue/min, previously found in healthy subjects (p<0.001), in accordance with decreased metabolic function in cirrhotic livers. Mean CoV for Kmet in liver tissue was 24.4% in patients and 14.4% in healthy subjects (p<0.0001). The degree of intrahepatic metabolic heterogeneity correlated positively with HVPG (p<0.05).

CONCLUSIONS

A 20-min dynamic FDGal PET/CT with arterial sampling provides an accurate measure of regional hepatic metabolic function in patients with cirrhosis. This is likely to have clinical implications for the assessment of patients with liver disease as well as treatment planning and monitoring.

Cirrhosis Regression and Subclassification

The end point of liver fibrosis in almost all chronic liver diseases is cirrhosis. Progression to cirrhosis is accompanied by vascular remodeling and regeneration with important functional and hemodynamic consequences that include development of portal hypertension and eventually decompensation and death. Fibrosis can regress following successful treatment of the underlying disease. However, most common fibrosis scoring systems are not equipped for assessing this aspect. Nodule size, septal width and fibrosis area seem to correlate with disease severity and progression in cirrhosis. Classification systems based on nodule size, septal width, and fibrosis area need to be further validated.

Cirrhosis histology and Laennec staging system correlate with high portal pressure

AIMS

To correlate cirrhosis histology and Laennec fibrosis scoring with portal pressure, as determined by hepatic venous pressure gradient (HVPG).

METHODS AND RESULTS

One hundred and four patients with biopsy-proven cirrhosis and known HVPG were included in the study. Semiquantitative scoring of 12 histological parameters and quantitative assessment by morphometry for septal thickness and nodule diameter and image analysis for fibrosis were performed. Laennec histological subgrading and clinical staging of cirrhosis were also performed. There were significant positive correlations between HVPG and Laennec histological grade of cirrhosis (P < 0.001), micronodularity (P < 0.001), the presence of thick fibrous septa (P = 0.015), the amount of collagen in the space of Disse (P < 0.001), and the extent of fibrosis by image analysis (P = 0.003). Multivariate analysis, to predict high HVPG (≥16 mmHg), showed that degree of collagen in the space of Disse [P = 0.007, odds ratio (OR) 19.3], histological grade of cirrhosis (P = 0.017, OR 3.9) and micronodularity (P = 0.02, OR 3.5) independently predicted high HVPG.

CONCLUSIONS

Histological subclassification of cirrhosis, collagen in the space of Disse and micronodularity are independent predictors of high portal pressure. The Laennec histological subclassification of cirrhosis correlates well with clinical severity of cirrhosis, and can provide useful prognostic information.

Assessing portal hypertension in liver diseases

Portal hypertension is a common complication of chronic liver diseases and is responsible for most clinical consequences of cirrhosis, which represent the more frequent causes of death and liver transplantation in these patients. This review is aimed at clarifying the state-of-the art assessment of portal hypertension and at discussing recent developments in this field. Particular attention is paid to new noninvasive techniques that will be soon available for potential routine use.

Sample size requirement for digital image analysis of collagen proportionate area in cirrhotic livers

AIMS

   The requirements for adequate cirrhotic liver biopsy size have not been established for quantitative fibrosis measurements (collagen proportionate area: CPA). We evaluated the CPA of virtual biopsies in cirrhosis to elucidate (i) the amount of tissue required to achieve reliable CPA measurements and (ii) the effect of aetiology on sample size requirements.

METHOD AND RESULTS

   A total of 120 cirrhotic tissue blocks (six aetiologies) were studied. A representative 100 mm(2) region was selected from each block and a reference CPA measured. Each image (n = 120) was divided into 100 × 1 mm(2) images; CPA was measured for each 1 mm(2) and virtual biopsies of different sizes were created from the 1 mm(2) components. For each virtual biopsy size the probability that the virtual biopsy CPA would be within 5% of the reference CPA was calculated. There were 441 000 virtual biopsies. Biopsy size versus probability plots indicated that, for 90% probability that the virtual biopsy CPA can be expected to be within 5% of the reference CPA, 22-28 mm(2) of analysable tissue is required depending on liver disease aetiology; and that a 75% probability level requires a biopsy with 12-15 mm(2) of analysable tissue.

CONCLUSION

   The sample size required for a given probability level depends on the aetiology of cirrhosis, and this should be taken into account when judging the reliability of cirrhotic liver biopsy CPA.

Salvianolic Acid B reducing portal hypertension depends on macrophages in isolated portal perfused rat livers with chronic hepatitis

This study is aimed to investigate the effects of Sal B on portal hypertension (PH). PH with chronic hepatitis was induced by carbon tetrachloride (CCl₄) in rats. The model was confirmed with elevated portal pressures and increased serum CD163 levels. The inducible nitric oxide synthase (iNOS) or heme oxygenase-1 (HO-1) in portal triads was assessed. The isolated portal perfused rat liver (IPPRL) was performed at d₀, d₂₈, d₅₆ , and d₈₄ in the progression of chronic hepatitis. After constricting with phenylephrine, the portal veins were relaxed with Sal B. The EC₅₀ of Sal B for relaxing portal veins was −2.04 × 10⁻⁹, 7.28 × 10⁻¹¹, 1.52 × 10⁻¹¹, and 8.44 × 10⁻¹¹ mol/L at d₀, d₂₈, d₅₆, and d₈₄, respectively. More macrophages infiltrated in portal triads and expressed more iNOS or HO-1 as PH advanced. The areas under the curve (AUCs) of Sal B for reducing PH were positively correlated with the levels of iNOS or HO-1 in portal triads, and so did with serum CD163 levels. Sal B reduces PH in IPPRL with chronic hepatitis, via promoting portal relaxation due to macrophage-originated NO or CO in portal triads, partly at least.