Prognostic value of liver stiffness in patients hospitalized for acute decompensated heart failure: a meta-analysis

PURPOSE

Heart failure (HF) is a major health problem affecting millions of people worldwide. In the latest years, many efforts have been made to identify predictors of poor prognosis in these patients. The aim of this systematic review and meta-analysis was to enlighten the correlation between liver stiffness (LS), assessed by Shear Wave Elastography techniques, and HF, particularly focusing on the prognostic value of LS on cardiovascular outcomes.

METHODS

We searched the PUBMED databases (up to May 1st, 2023) for studies that enlightened the correlation between LS and cardiovascular outcomes in patients hospitalized for acute decompensated heart failure (ADHF). We performed a meta-analysis to estimate the efficacy of LS in predicting the prognosis of patients with ADHF.

RESULTS

We analyzed data from 7 studies, comprising 677 patients, that assessed the prognostic value of LS in predicting cardiovascular outcomes in patients hospitalized for ADHF. The pooled analysis showed that increased liver stiffness was associated with higher risk of adverse cardiac events (hazard ratio 1.07 [1.03, 1.12], 95% CI).

CONCLUSION

Increased LS is associated with poor prognosis in patients hospitalized for HF and might help effectively identify those patients at high risk for worse outcomes.

Dynamic Contrast-Enhanced Ultrasound in the Prediction of Advanced Hepatocellular Carcinoma Response to Systemic and Locoregional Therapies

Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer and the sixth most common malignant tumor in the world, with an incidence of 2-8% per year in patients with hepatic cirrhosis or chronic hepatitis. Despite surveillance schedules, it is sometimes diagnosed at an advanced stage, requiring complex therapeutic efforts with both locoregional and systemic treatments. Traditional radiological tools (computed tomography and magnetic resonance) are used for the post-treatment follow-up of HCC. The first follow-up imaging is performed at 4 weeks after resection or locoregional treatments, or after 3 months from the beginning of systemic therapies, and subsequently every 3 months for the first 2 years. For this reason, these radiological methods do not grant the possibility of an early distinction between good and poor therapeutic response. Contrast-enhanced ultrasound (CEUS) and dynamic contrast-enhanced ultrasound (DCE-US) have gained the interest of several researchers for their potential role in the early assessment of response to locoregional treatments (chemoembolization) or antiangiogenic therapies in patients with advanced HCC. In fact, DCE-US, through a quantitative analysis performed by specific software, allows the construction of time-intensity curves, providing an evaluation of the parameters related to neoplastic tissue perfusion and its potential changes following therapies. It has the invaluable advantage of being easily repeatable, minimally invasive, and able to grant important evaluations regarding patients' survival, essential for well-timed therapeutic changes in case of unsatisfying response, and eventual further treatment planning.

Role of Intestinal Inflammation and Permeability in Patients with Acute Heart Failure

Background and Objectives: Heart failure (HF) represents a major health burden. Although several treatment regimens are available, their effectiveness is often unsatisfactory. Growing evidence suggests a pivotal role of the gut in HF. Our study evaluated the prognostic role of intestinal inflammation and permeability in older patients with acute HF (AHF), and their correlation with the common parameters traditionally used in the diagnostic-therapeutic management of HF. Materials and Methods: In a single-center observational, prospective, longitudinal study, we enrolled 59 patients admitted to the Emergency Department (ED) and then hospitalized with a diagnosis of AHF, from April 2022 to April 2023. Serum routine laboratory parameters and transthoracic echocardiogram were assayed within the first 48 h of ED admission. Fecal calprotectin (FC) and both serum and fecal levels of zonulin were measured, respectively, as markers of intestinal inflammation and intestinal permeability. The combined clinical outcome included rehospitalizations for AHF and/or death within 90 days. Results: Patients with increased FC values (>50 µg/g) showed significantly worse clinical outcomes (p < 0.001) and higher median levels of NT-proBNP (p < 0.05). No significant correlation was found between the values of fecal and serum zonulin and the clinical outcome. Median values of TAPSE were lower in those patients with higher values of fecal calprotectin (p < 0.05). After multivariate analysis, NT-proBNP and FC values > 50 µg/g resulted as independent predictors of a worse clinical outcome. Conclusions: Our preliminary finding supports the hypothesis of a close relationship between the gut and heart, recognizing in a specific marker of intestinal inflammation such as FC, an independent predictive prognostic role in patients admitted for AHF. Further studies are needed to confirm these results, as well as investigate the reliability of new strategies targeted at modulation of the intestinal inflammatory response, and which are able to significantly impact the course of diseases, mainly in older and frail patients.

Dynamics of liver stiffness predicts complications in patients with HCV related cirrhosis treated with direct-acting antivirals

BACKGROUND

Direct acting antivirals(DAAs) are effective in reducing inflammatory ant fibrotic markers in patients with chronic hepatitis C virus(HCV) infection and to prevent liver-related complications. Two-dimensional shear wave elastography(2D-SWE) is an effective technique for the assessment of liver fibrosis.

AIM

To evaluate changes in liver stiffness(LS) in HCV cirrhotic patients undergoing DAA therapy and to identify non-invasive parameters that predict the occurrence of liver-related events.

METHODS

We enrolled 229 patients who received DAAs between January 2015 and October 2018. Ultrasound parameters and laboratory data were assessed before treatment and 24(T1) and 48(T2) weeks after end of treatment. Patients were followed up every 6 months to evaluate the development of HCC and other liver related complications. Multiple Cox regression analysis was used to determine parameters associated with the development of complications.

RESULTS

Model for End-stage Liver Disease(MELD) score(HR 1.16; CI 95% 1.01-1.33; p = 0.026) and a change in LS at T2(1-year Delta LS) < 20%(HR 2.98; CI 95% 1.01-8.1; p = 0.03) were independently associated with HCC risk. One-year Delta-LS <20% was independently associated with the development of ascites(HR 5.08; CI 95% 1.03 - 25.14; p = 0.04).

CONCLUSIONS

Dynamic changes of 2D-SWE-measured LS after DAA therapy may be a useful tool to identify patients who are at higher risk of liver related complications.

Molecular Mechanisms Underlying Detection Sensitivity in Nanoparticle-Assisted NMR Chemosensing

Nanoparticle-assisted nuclear magnetic resonance (NMR) chemosensing exploits monolayer-protected nanoparticles as supramolecular hosts to detect small molecules in complex mixtures via nuclear Overhauser effect experiments with detection limits down to the micromolar range. Still, the structure-sensitivity relationships at the basis of such detection limits are little understood. In this work, we integrate NMR spectroscopy and atomistic molecular dynamics simulations to examine the covariates that affect the sensitivity of different NMR chemosensing experiments [saturation transfer difference (STD), water STD, and high-power water-mediated STD]. Our results show that the intensity of the observed signals correlates with the number and duration of the spin-spin interactions between the analytes and the nanoparticles and/or between the analytes and the nanoparticles' solvation molecules. In turn, these parameters depend on the location and dynamics of each analyte inside the monolayer. This insight will eventually facilitate the tailoring of experimental and computational setups to the analyte's chemistry, making NMR chemosensing an even more effective technique in practical use.

Noninvasive Evaluation of Clinically Significant Portal Hypertension in Patients with Liver Cirrhosis: The Role of Contrast-Enhanced Ultrasound Perfusion Imaging and Elastography

BACKGROUND

Hepatic venous pressure gradient (HVPG) is the gold standard for assessing the degree of portal hypertension (PH), but it is not suitable for routine clinical use. The recently developed ultrasonography techniques, dynamic contrast-enhanced ultrasound (D-CEUS) and liver stiffness (LS), have expanded the possibilities for noninvasive evaluation.

AIMS

To investigate the usefulness of D-CEUS and elastographic parameters in assessing the presence and degree of PH.

METHODS

This is a prospective monocentric study. Patients with liver cirrhosis referred for HVPG measurements underwent hepatic Doppler ultrasound, LS measurement, and D-CEUS with a second-generation contrast agent. Pearson's correlation and a receiver operating characteristic (ROC) curve analysis were performed to assess the role of noninvasive findings in predicting clinically significant PH (CSPH) and severe PH (SPH).

RESULTS

46 consecutive patients (31 men; mean age±SD: 57±11 years) were enrolled. A significant positive correlation was noted between LS and HVPG (r = 0.809, p<0.0001) with an area under the ROC curve of 0.923. A cut-off value of 24.2 kPa best predicted CSPH with a positive predictive value of 85%. Among the D-CEUS features, the area under the ROC curves of liver parenchyma peak intensity (PI-LP) was greater than the other indices both for CSPH and SPH (1.000 and 0.981, respectively). A PI-LP under 23.3 arbitrary units indicated the presence of CSPH with a sensitivity and a specificity of 100%.

CONCLUSION

A multimodal ultrasound approach based on D-CEUS and LS might become a reliable predictor of CSPH and SPH and a useful alternative to HVPG.

Dynamic contrast enhanced ultrasound in gastrointestinal diseases: A current trend or an indispensable tool?

Contrast enhanced ultrasound (CEUS) has been widely implemented in clinical practice because of the enormous quantity of information it provides, along with its low cost, reproducibility, minimal invasiveness, and safety of the second-generation ultrasound contrast agents. To overcome the limitation of CEUS given by the subjective evaluation of the contrast enhancement behaviour, quantitative analysis of contrast kinetics with generation of time-intensity curves has been introduced in recent years. The quantification of perfusion parameters [named as dynamic-CEUS (D-CEUS)] has several applications in gastrointestinal neoplastic and inflammatory disorders. However, the limited availability of large studies and the heterogeneity of the technologies employed have precluded the standardisation of D-CEUS, which potentially represents a valuable tool for clinical practice in management of gastrointestinal diseases. In this article, we reviewed the evidence exploring the application of D-CEUS in gastrointestinal diseases, with a special focus on liver, pancreas, and inflammatory bowel diseases.

The Role of Transabdominal Ultrasound Elastography in Gastrointestinal Non-Liver Diseases: Current Application and Future Prospectives

Ultrasound imaging is the first-line investigation for patients with abdominal symptoms, as it effectively depicts the gastrointestinal tract and enables the diagnosis of multiple pathological conditions. Among different recent ultrasound technological advancements, elastography enables the evaluation of various tissue characteristics, such as neoplastic transformation or fibroinflammatory status. In recent years, ultrasound elastography has been utilized extensively for the study of liver diseases and in numerous other clinical settings, including gastrointestinal diseases. Current guidelines suggest the use of transabdominal ultrasound elastography to characterize bowel wall lesions, to assess gastrointestinal contractility, to diagnose and grade chronic pancreatitis; however, no specific indications are provided. In the present paper, we summarize the evidence concerning the application of different ultrasound elastography modalities in gastrointestinal non-liver diseases.

Contrast-Enhanced Imaging in the Management of Intrahepatic Cholangiocarcinoma: State of Art and Future Perspectives

Intrahepatic cholangiocarcinoma (iCCA) represents the second most common liver cancer after hepatocellular carcinoma, accounting for 15% of primary liver neoplasms. Its incidence and mortality rate have been rising during the last years, and total new cases are expected to increase up to 10-fold during the next two or three decades. Considering iCCA's poor prognosis and rapid spread, early diagnosis is still a crucial issue and can be very challenging due to the heterogeneity of tumor presentation at imaging exams and the need to assess a correct differential diagnosis with other liver lesions. Abdominal contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) plays an irreplaceable role in the evaluation of liver masses. iCCA's most typical imaging patterns are well-described, but atypical features are not uncommon at both CT and MRI; on the other hand, contrast-enhanced ultrasound (CEUS) has shown a great diagnostic value, with the interesting advantage of lower costs and no renal toxicity, but there is still no agreement regarding the most accurate contrastographic patterns for iCCA detection. Besides diagnostic accuracy, all these imaging techniques play a pivotal role in the choice of the therapeutic approach and eligibility for surgery, and there is an increasing interest in the specific imaging features which can predict tumor behavior or histologic subtypes. Further prognostic information may also be provided by the extraction of quantitative data through radiomic analysis, creating prognostic multi-parametric models, including clinical and serological parameters. In this review, we aim to summarize the role of contrast-enhanced imaging in the diagnosis and management of iCCA, from the actual issues in the differential diagnosis of liver masses to the newest prognostic implications.

Shear Wave Dispersion in Chronic Liver Disease: From Physical Principles to Clinical Usefulness

The development of new applications in ultrasound (US) imaging in recent years has strengthened the role of this imaging technique in the management of different pathologies, particularly in the setting of liver disease. Improved B-mode imaging (3D and 4D), contrast-enhanced US (CEUS) and especially US-based elastography techniques have created the concept of multiparametric ultrasound (MP-US), a term borrowed from radiological sectional imaging. Among the new elastography techniques, shear wave dispersion is a newly developed imaging technology which enables the assessment of the shear waves' dispersion slope. The analysis of the dispersion qualities of shear waves might be indirectly related to the tissue viscosity, thus providing biomechanical information concerning the pathologic state of the liver such as necroinflammation. Some of the most recent US devices have been embedded with software that evaluate the dispersion of shear waves/liver viscosity. In this review, the feasibility and the clinical applications of liver viscosity are reviewed based on the preliminary findings of both animal and human studies.

Bariatric-metabolic surgery versus lifestyle intervention plus best medical care in non-alcoholic steatohepatitis (BRAVES): a multicentre, open-label, randomised trial

BACKGROUND

Observational studies suggest that bariatric-metabolic surgery might greatly improve non-alcoholic steatohepatitis (NASH). However, the efficacy of surgery on NASH has not yet been compared with the effects of lifestyle interventions and medical therapy in a randomised trial.

METHODS

We did a multicentre, open-label, randomised trial at three major hospitals in Rome, Italy. We included participants aged 25-70 years with obesity (BMI 30-55 kg/m2), with or without type 2 diabetes, with histologically confirmed NASH. We randomly assigned (1:1:1) participants to lifestyle modification plus best medical care, Roux-en-Y gastric bypass, or sleeve gastrectomy. The primary endpoint of the study was histological resolution of NASH without worsening of fibrosis at 1-year follow-up. This study is registered at ClinicalTrials.gov, NCT03524365.

FINDINGS

Between April 15, 2019, and June 21, 2021, we biopsy screened 431 participants; of these, 103 (24%) did not have histological NASH and 40 (9%) declined to participate. We randomly assigned 288 (67%) participants with biopsy-proven NASH to lifestyle modification plus best medical care (n=96 [33%]), Roux-en-Y gastric bypass (n=96 [33%]), or sleeve gastrectomy (n=96 [33%]). In the intention-to-treat analysis, the percentage of participants who met the primary endpoint was significantly higher in the Roux-en-Y gastric bypass group (54 [56%]) and sleeve gastrectomy group (55 [57%]) compared with lifestyle modification (15 [16%]; p<0·0001). The calculated probability of NASH resolution was 3·60 times greater (95% CI 2·19-5·92; p<0·0001) in the Roux-en-Y gastric bypass group and 3·67 times greater (2·23-6·02; p<0·0001) in the sleeve gastrectomy group compared with in the lifestyle modification group. In the per protocol analysis (236 [82%] participants who completed the trial), the primary endpoint was met in 54 (70%) of 77 participants in the Roux-en-Y gastric bypass group and 55 (70%) of 79 participants in the sleeve gastrectomy group, compared with 15 (19%) of 80 in the lifestyle modification group (p<0·0001). No deaths or life-threatening complications were reported in this study. Severe adverse events occurred in ten (6%) participants who had bariatric-metabolic surgery, but these participants did not require re-operations and severe adverse events were resolved with medical or endoscopic management.

INTERPRETATION

Bariatric-metabolic surgery is more effective than lifestyle interventions and optimised medical therapy in the treatment of NASH.

FUNDING

Fondazione Policlinico Universitario A Gemelli, Policlinico Universitario Umberto I and S Camillo Hospital, Rome, Italy.

Correlation between a New Point-Shear Wave Elastography Device (X+pSWE) with Liver Histology and 2D-SWE (SSI) for Liver Stiffness Quantification in Chronic Liver Disease

BACKGROUND

The aim of this study was to investigate the feasibility, the correlation with previously validated 2D-SWE by supersonic imagine (SSI), and the accuracy in fibrosis-staging of a novel point shear-wave elastography device (X+pSWE) in patients with chronic liver disease.

METHODS

This prospective study included 253 patients with chronic liver diseases, without comorbidities potentially affecting liver stiffness. All patients underwent X+pSWE and 2D-SWE with SSI. Among them 122 patients also underwent liver biopsy and were classified according to histologic fibrosis. Agreement between the equipment was assessed with Pearson coefficient and Bland-Altman analysis, while receiver operator characteristic curve (ROC) analysis with Youden index was used to establish thresholds for fibrosis staging.

RESULTS

A very good correlation was found between X+pSWE and 2D-SWE with SSI (r2 = 0.94; p < 0.001), with X+pSWE average liver stiffness values 0.24 kPa lower than those obtained with SSI. AUROC of X+pSWE for the staging of significant fibrosis (F2), severe fibrosis (F3) and cirrhosis (F4) using SSI as a reference standard was 0.96 (95% CI, 0.93-0.99), 0.98 (95% CI, 0.97-1) and 0.99 (95% CI, 0.98-1), respectively. The best cut-off values for diagnosing fibrosis ≥F2, ≥F3 and F4 were, respectively, 6.9, 8.5 and 12 for X+pSWE. According to histologic classification, X+pSWE correctly identified 93 out of 113 patients (82%) for F ≥ 2 and 101 out of 113 patients (89%) for F ≥ 3 using the aforementioned cut-off values.

CONCLUSION

X+pSWE is a useful novel non-invasive technique for staging liver fibrosis in patients with chronic liver disease.

Multiparametric Dynamic Ultrasound Approach for Differential Diagnosis of Primary Liver Tumors

A correct differentiation between hepatocellular carcinoma (HCC) and intracellular cholangiocarcinoma (ICC) is essential for clinical management and prognostic prediction. However, non-invasive differential diagnosis between HCC and ICC remains highly challenging. Dynamic contrast-enhanced ultrasound (D-CEUS) with standardized software is a valuable tool in the diagnostic approach to focal liver lesions and could improve accuracy in the evaluation of tumor perfusion. Moreover, the measurement of tissue stiffness could add more information concerning tumoral environment. To explore the diagnostic performance of multiparametric ultrasound (MP-US) in differentiating ICC from HCC. Our secondary aim was to develop an US score for distinguishing ICC and HCC. Between January 2021 and September 2022 consecutive patients with histologically confirmed HCC and ICC were enrolled in this prospective monocentric study. A complete US evaluation including B mode, D-CEUS and shear wave elastography (SWE) was performed in all patients and the corresponding features were compared between the tumor entities. For better inter-individual comparability, the blood volume-related D-CEUS parameters were analyzed as a ratio between lesions and surrounding liver parenchyma. Univariate and multivariate regression analysis was performed to select the most useful independent variables for the differential diagnosis between HCC and ICC and to establish an US score for non-invasive diagnosis. Finally, the diagnostic performance of the score was evaluated by receiver operating characteristic (ROC) curve analysis. A total of 82 patients (mean age ± SD, 68 ± 11 years, 55 men) were enrolled, including 44 ICC and 38 HCC. No statistically significant differences in basal US features were found between HCC and ICC. Concerning D-CEUS, blood volume parameters (peak intensity, PE; area under the curve, AUC; and wash-in rate, WiR) showed significantly higher values in the HCC group, but PE was the only independent feature associated with HCC diagnosis at multivariate analysis (p = 0.02). The other two independent predictors of histological diagnosis were liver cirrhosis (p < 0.01) and SWE (p = 0.01). A score based on those variables was highly accurate for the differential diagnosis of primary liver tumors, with an area under the ROC curve of 0.836 and the optimal cut-off values of 0.81 and 0.20 to rule in or rule out ICC respectively. MP-US seems to be a useful tool for non-invasive discrimination between ICC and HCC and could prevent the need for liver biopsy at least in a subgroup of patients.

NanoModeler CG: A Tool for Modeling and Engineering Functional Nanoparticles at a Coarse-Grained Resolution

Functionalized metal nanoparticles (NPs) are macromolecular assemblies with a tunable physicochemical profile that makes them interesting for biotechnology, materials science, and energy conversion. In this regard, molecular simulations offer a way to scrutinize the structural and dynamical features of monolayer-protected NPs and their interactions with relevant matrices. Previously, we developed NanoModeler, a webserver that automates the preparation of functionalized gold NPs for atomistic molecular dynamics (MD) simulations. Here, we present NanoModeler CG (www.nanomodeler.it), a new release of NanoModeler that now also allows the building and parametrizing of monolayer-protected metal NPs at a coarse-grained (CG) resolution. This new version extends our original methodology to NPs of eight different core shapes, conformed by up to 800,000 beads and coated by eight different monolayer morphologies. The resulting topologies are compatible with the Martini force field but are easily extendable to any other set of parameters parsed by the user. Finally, we demonstrate NanoModeler CG's capabilities by reproducing experimental structural features of alkylthiolated NPs and rationalizing the brush-to-mushroom phase transition of PEGylated anionic NPs. By automating the construction and parametrization of functionalized NPs, the NanoModeler series offers a standardized way to computationally model monolayer-protected nanosized systems.

Accurate liquid biopsy for the diagnosis of non-alcoholic steatohepatitis and liver fibrosis

OBJECTIVE

Clinical diagnosis and approval of new medications for non-alcoholic steatohepatitis (NASH) require invasive liver biopsies. The aim of our study was to identify non-invasive biomarkers of NASH and/or liver fibrosis.

DESIGN

This multicentre study includes 250 patients (discovery cohort, n=100 subjects (Bariatric Surgery Versus Non-alcoholic Steato-hepatitis - BRAVES trial); validation cohort, n=150 (Liquid Biopsy for NASH and Liver Fibrosis - LIBRA trial)) with histologically proven non-alcoholic fatty liver (NAFL) or NASH with or without fibrosis. Proteomics was performed in monocytes and hepatic stellate cells (HSCs) with iTRAQ-nano- Liquid Chromatography - Mass Spectrometry/Mass Spectrometry (LC-MS/MS), while flow cytometry measured perilipin-2 (PLIN2) and RAB14 in peripheral blood CD14⁺CD16^- monocytes. Neural network classifiers were used to predict presence/absence of NASH and NASH stages. Logistic bootstrap-based regression was used to measure the accuracy of predicting liver fibrosis.

RESULTS

The algorithm for NASH using PLIN2 mean florescence intensity (MFI) combined with waist circumference, triglyceride, alanine aminotransferase (ALT) and presence/absence of diabetes as covariates had an accuracy of 93% in the discovery cohort and of 92% in the validation cohort. Sensitivity and specificity were 95% and 90% in the discovery cohort and 88% and 100% in the validation cohort, respectively.The area under the receiver operating characteristic (AUROC) for NAS level prediction ranged from 83.7% (CI 75.6% to 91.8%) in the discovery cohort to 97.8% (CI 95.8% to 99.8%) in the validation cohort.The algorithm including RAB14 MFI, age, waist circumference, high-density lipoprotein cholesterol, plasma glucose and ALT levels as covariates to predict the presence of liver fibrosis yielded an AUROC of 95.9% (CI 87.9% to 100%) in the discovery cohort and 99.3% (CI 98.1% to 100%) in the validation cohort, respectively. Accuracy was 99.25%, sensitivity 100% and specificity 95.8% in the discovery cohort and 97.6%, 99% and 89.6% in the validation cohort. This novel biomarker was superior to currently used FIB4, non-alcoholic fatty liver disease fibrosis score and aspartate aminotransferase (AST)-to-platelet ratio and was comparable to ultrasound two-dimensional shear wave elastography.

CONCLUSIONS

The proposed novel liquid biopsy is accurate, sensitive and specific in diagnosing the presence and severity of NASH or liver fibrosis and is more reliable than currently used biomarkers.

CLINICAL TRIALS

Discovery multicentre cohort: Bariatric Surgery versus Non-Alcoholic Steatohepatitis, BRAVES, ClinicalTrials.gov identifier: NCT03524365.Validation multicentre cohort: Liquid Biopsy for NASH and Fibrosis, LIBRA, ClinicalTrials.gov identifier: NCT04677101.

Contrast-Enhanced Ultrasound Findings in Patients with Rare Solitary Necrotic Nodule of the Liver - a Multicenter Report

PURPOSE

 This multicenter retrospective study highlights the contrast-enhanced ultrasound (CEUS) findings in a series of histologically proven solitary necrotic nodules (SNN) of the liver, a poorly understood pathologic entity of uncertain origin that mimics malignancy.

MATERIALS AND METHODS

 22 patients (M/F 13/9; mean age 59.4 years, SD ± 10.7, range 35-81) with histological diagnosis of SNN and CEUS were selected from clinical, imaging, and pathological archives of 7 US interventional centers, each of which provided 1 to 6 cases (mean 2.8). Pathological diagnosis was made on 20 US-guided biopsies and 2 surgical specimens. 2 patients had 2 SNNs with identical CEUS findings so that imaging analysis was carried out on 24 nodules.

RESULTS

 SNN was an incidental finding in healthy people in 10 cases (45.5 %), and it was discovered during follow-up for either known extrahepatic malignancies (9 cases = 41 %) or chronic liver disease (3 cases = 13.5 %). SNNs had a mean size of 19.3 mm (SD ± 6.5, range 9-40). On B-mode US, SNNs appeared hypoechoic in 14 cases (66.7 %), "target-like" in 7 cases (29.2 %), and homogeneously hyperechoic in 1 case (4.1 %). On CEUS, all lesions appeared devoid of contrast enhancement ("punched out" aspect) in the arterial, portal venous, and late phases after US contrast agent injection. A uniformly thin, hyperenhancing ring in the early arterial phase and isoenhanced with the surrounding parenchyma in the portal venous and late phases was found in 10 nodules (41.6 %). Clinical and imaging follow-up (mean duration 42.2 months, SD ± 34.9, range 2-108) was available in 15 patients with 16 SNNs: no changes in size and echostructure were seen.

CONCLUSION

 CEUS can contribute to the diagnosis of SNN when a "punched out" appearance in all vascular phases with or without thin rim enhancement in the very early arterial phase is present in healthy subjects in whom a focal liver lesion is incidentally found. In patients with a history of chronic liver disease or malignancy, US-guided biopsy represents the unavoidable first-line diagnostic modality.

ADAMTS-13/von Willebrand factor ratio: A prognostic biomarker for portal vein thrombosis in compensated cirrhosis. A prospective observational study

BACKGROUND AND AIMS

In cirrhosis, decreased portal flow velocity, thrombophilia factors, and portal hypertension are considered risk factors for portal vein thrombosis (PVT). In cirrhosis, the transformation of the stellate cells causes a progressive decrease of ADAMTS-13, while VWF multimers secretion by endothelial cells is strongly enhanced. This imbalance leads to an accumulation of ultra-large VWF multimers that in sinusoidal circulation could favor PVT both in intra- and extra-hepatic branches, mostly in decompensated cirrhosis. This prospective study was aimed at identifying possible clinical, biochemical, and hemostatic factors predictive for non-tumoral PVT in a cohort of patients with compensated cirrhosis.

METHODS

Seventynine compensated cirrhosis patients were prospectively followed for 48 months, receiving a periodic Doppler-ultrasound liver examination associated with an extensive evaluation of clinical, biochemical, and hemostatic profile.

RESULTS

Five patients developed PVT (cumulative prevalence = 6.3%), occurring 4-36 months after enrollment. In logistic regression analysis, the ADAMTS-13/VWF:GpIbR ratio < 0.4 was the only independent variable significantly associated with PVT (OR 14.6, 95% C.I.:1.36-157.2, p = 0.027). A Cox-regression-analysis confirmed this finding (HR = 7.7, p = 0.027).

CONCLUSIONS

The ADAMTS-13/VWF ratio < 0.4 measured in compensated cirrhosis could be a reliable predictive biomarker for PVT development, paving the way to novel therapeutic strategies to prevent and treat PVT in this clinical setting.

Prevalence and predictors of non-alcoholic steatohepatitis in subjects with morbid obesity and with or without type 2 diabetes

AIM

To investigate the prevalence of biopsy-proven non-alcoholic steatohepatitis (NASH) in a cohort of patients with morbid obesity and with or without type 2 diabetes (T2D) and to find non-invasive predictors of NASH severity.

METHODS

We evaluated a cohort of 412 subjects (age 19-67 years, body mass index-BMI: 44.98 kg/m²), who underwent fine-needle liver biopsy during bariatric surgery. Thirty-six percent of the subjects were affected by T2D. Liver biopsies were classified according to the Kleiner's NAFLD Activity Score (NAS). NAFLD Fibrosis Score (NFS), AST/ALT ratio, AST to Platelet ratio (APRI), fibrosis-4 score (FIB4) were calculated. A neural network analysis (NNA) was run to predict NASH severity.

RESULTS

The prevalence of biopsy-proven NASH was 63% and 78% in subjects with obesity and without or with T2D, respectively. T2D doubled the risk of NASH [OR 2.079 (95% IC=1.31-3.29)]. The prevalence of NAFL increased with the increase of BMI, while there was an inverse correlation between BMI and NASH (r=-0.145 p=0.003). Only mild liver fibrosis was observed. HOMA-IR was positively associated with hepatocyte ballooning (r=0.208, p<0.0001) and fibrosis (r=0.159, p=0.008). The NNA highlighted a specificity of 77.3% using HDL-cholesterol, BMI, and HOMA-IR as main determinants of NASH.

CONCLUSIONS

Our data show a higher prevalence of NASH in patients with morbid obesity than reported in the literature and the pivotal role of T2D among the risk factors for NASH development. However, the inverse correlation observed between BMI and biopsy-proven NASH suggests that over a certain threshold adiposity can be somewhat protective against liver damage. Our model predicts NASH presence with high specificity, thus helping identifying subjects who should promptly undergo liver biopsy.

The Gemelli Ultrasound Chronic Pancreatitis Score: A Non-invasive Tool for the Diagnosis of Chronic Pancreatitis

A dedicated ultrasound (US) score, the Gemelli Ultrasound Chronic Pancreatitis (USCP) score, could be useful in the follow-up of patients with chronic pancreatitis (CP). However, its role in the diagnosis of CP has not been investigated. We aimed to evaluate the role of the Gemelli USCP score in the diagnosis of CP and the agreement with standard imaging techniques. Ninety-three patients clinically suspected of having CP and referred to the pancreatic outpatient clinic of A. Gemelli Hospital for endoscopic ultrasound (EUS) were prospectively enrolled. All patients underwent pancreatic US to calculate the Gemelli USCP score. A receiver operating characteristic curve analysis was also performed to assess the performance of the US score in CP diagnosis. The Gemelli USCP score was inversely related to the Rosemont score for both total value (p < 0.0001) and each parameter evaluated (p < 0.0001). This score was significantly higher in patients with CP with an excellent area under the receiver operating characteristic curve (0.946) and the optimal cutoff of 5. Moreover, we found a significant correlation between the Gemelli USCP score and laboratory parameters related to pancreatic exocrine insufficiency (p < 0.0001). The development of a dedicated ultrasound score could be useful as a non-invasive tool in the diagnosis of CP.

Correlation Between QElaXto Techniques and Supersonic Imagine for Liver Stiffness Quantification in Chronic Liver Disease

OBJECTIVES

Intersystem variability in liver stiffness (LS) quantification with ultrasound shear wave elastography (SWE) precludes direct comparison of results obtained with different equipment. The aim of this study was to investigate the agreement between point-SWE and 2-dimensional-SWE with Esaote-MyLab 9 (p-QElaXto and 2D-QElaXto, respectively) and 2D-SWE with SuperSonic Imagine (SSI) in order to assess specific LS thresholds for fibrosis staging with QElaXto techniques, using SSI as a reference standard.

METHODS

A total of 235 compensated chronic liver disease (CLD) patients without comorbidities potentially affecting LS were enrolled in the study. Among them, 101 patients underwent also liver biopsy. Agreement between the equipment was assessed with Pearson coefficient and Bland-Altman analysis, while cut-off values were calculated with receiver operating characteristics analysis.

RESULTS

Correlation between 2D-QElaXto and p-QElaXto with SSI resulted very good (r = 0.898 and r = 0.866), especially in precirrhotic stages, with a mean difference between LS values of -1.3 kPa for 2D-QElaXto and -0.6 kPa for p-QElaXto compared with SSI. Cut-off thresholds for diagnosing fibrosis ≥F2, ≥F3, and F4 in non-HBV-related CLD were, respectively, 5.5, 8.0, and 10.6 kPa for 2D-QElaXto and 6.1, 8.1, and 11.7 kPa for p-QElaXto. All three SWE techniques were effective in differentiating significant fibrosis ≥F2 from mild or absent fibrosis in the subgroup of patients submitted to biopsy and showed good feasibility.

CONCLUSIONS

Correlation between QElaXto techniques and SSI in LS measurements is very good. Our study identifies for the first time cut-off thresholds for fibrosis staging in non-HBV-related CLD using two QElaXto techniques.

Contrast-Enhanced Ultrasound for Monitoring Treatment Response in Different Stages of Hepatocellular Carcinoma

Simple Summary

The evaluation of tumor response to anti-cancer therapy is critical in oncology for the prompt determination of subsequent treatment and follow-up strategies. Historically, response criteria have been based on tumor size changes; however, since the development of locoregional and molecular-targeted therapies in HCC (which act by disrupting tumor vascularization rather than tumor cells), changes in tumor vascularity and enhancement patterns have been considered to be more reliable. Contrast-enhanced ultrasound (CEUS) and dynamic CEUS, which allow microvessel perfusion studies, are emerging as promising tools for early tumor response evaluation. This article provides a general review of the current literature regarding the usefulness of CEUS in monitoring HCC response to therapy, highlighting the role of the procedure at different stages of the disease.

Abstract

The capacity of contrast-enhanced ultrasound (CEUS) to detect microvessel perfusion has received much attention in cancer imaging since it can be used to evaluate the enhancement patterns of the lesions during all vascular phases in real time, with higher temporal resolution as compared other imaging modalities. A rich body of literature has demonstrated the potential usefulness of CEUS in the assessment of HCC in response to both locoregional and systemic therapies. It is useful to evaluate the efficacy of ablation immediately after treatment to provide guidance for the retreatment of residual unablated tumors. In patients treated with transarterial chemoembolization (TACE), CEUS showed a high degree of concordance with computed tomography and magnetic resonance for the differentiation of responders from non-responders. Dynamic CEUS (D-CEUS) has emerged as a promising tool for the depicting changes in tumor perfusion during anti-angiogenetic treatment that can be associated with tumor response and clinical outcome. This article provides a general review of the current literature regarding the usefulness of CEUS in monitoring HCC response to therapy, highlighting the role of the procedure in different stages of the disease.

Elastography as a predictor of liver cirrhosis complications after hepatitis C virus eradication in the era of direct-acting antivirals

Chronic inflammation due to hepatitis C virus (HCV) infection leads to liver fibrosis and rearrangement of liver tissue, which is responsible for the development of portal hypertension (PH) and hepatocellular carcinoma (HCC). The advent of direct-acting antiviral drugs has revolutionized the natural history of HCV infection, providing an overall eradication rate of over 90%. Despite a significant decrease after sustained virological response (SVR), the rate of HCC and liver-related complications is not completely eliminated in patients with advanced liver disease. Although the reasons are still unclear, cirrhosis itself has a residual risk for the development of HCC and other PH-related complications. Ultrasound elastography is a recently developed non-invasive technique for the assessment of liver fibrosis. Following the achievement of SVR, liver stiffness (LS) usually decreases, as a consequence of reduced inflammation and, possibly, fibrosis. Recent studies emphasized the application of LS assessment in the management of patients with SVR in order to define the risk for developing the complications of chronic liver disease (functional decompensation, gastrointestinal bleeding, HCC) and to optimize long-term prognostic outcomes in clinical practice.

Role of Contrast-Enhanced Ultrasound in the Detection of Complications After Ultrasound-Guided Liver Interventional Procedures

The role of contrast-enhanced ultrasound (CEUS) in interventional ultrasound-guided procedures in the liver has been increasingly recognized. However, little is known about the capability of CEUS for diagnosing complications after liver biopsy and ablation with special regard to postprocedural hemorrhage. The aim of this Pictorial Essay is to present the CEUS features of a wide spectrum of vascular complications (with or without bleeding) and injuries of the surrounding abdominal and chest wall occurring after liver interventional procedures.

On the Metal-Aided Catalytic Mechanism for Phosphodiester Bond Cleavage Performed by Nanozymes

Recent studies have shown that gold nanoparticles (AuNPs) functionalized with Zn(II) complexes can cleave phosphate esters and nucleic acids. Remarkably, such synthetic nanonucleases appear to catalyze metal (Zn)-aided hydrolytic reactions of nucleic acids similar to metallonuclease enzymes. To clarify the reaction mechanism of these nanocatalysts, here we have comparatively analyzed two nanonucleases with a >10-fold difference in the catalytic efficiency for the hydrolysis of the 2-hydroxypropyl-4-nitrophenylphosphate (HPNP, a typical RNA model substrate). We have used microsecond-long atomistic simulations, integrated with NMR experiments, to investigate the structure and dynamics of the outer coating monolayer of these nanoparticles, either alone or in complex with HPNP, in solution. We show that the most efficient one is characterized by coating ligands that promote a well-organized monolayer structure, with the formation of solvated bimetallic catalytic sites. Importantly, we have found that these nanoparticles can mimic two-metal-ion enzymes for nucleic acid processing, with Zn ions that promote HPNP binding at the reaction center. Thus, the two-metal-ion-aided hydrolytic strategy of such nanonucleases helps in explaining their catalytic efficiency for substrate hydrolysis, in accordance with the experimental evidence. These mechanistic insights reinforce the parallelism between such functionalized AuNPs and proteins toward the rational design of more efficient catalysts.

Association Mechanism of Peptide-Coated Metal Nanoparticles with Model Membranes: A Coarse-Grained Study

Functionalized metal nanoparticles (NPs) hold great promise as innovative tools in nanomedicine. However, one of the main challenges is how to optimize their association with the cell membrane, which is critical for their effective delivery. Recent findings show high cellular uptake rates for NPs coated with the polycationic cell-penetrating peptide gH625-644 (gH), although the underlying internalization mechanism is poorly understood. Here, we use extended coarse-grained simulations and free energy calculations to study systems that simultaneously include metal NPs, peptides, lipids, and sterols. In particular, we investigate the first encounter between multicomponent model membranes and 2.5 nm metal NPs coated with gH (gHNPs), based on the evidence from scanning transmission electron microscopy. By comparing multiple membrane and (membranotropic) NP models, we found that gHNP internalization occurs by forming an intermediate state characterized by specific stabilizing interactions formed by peptide-coated nanoparticles with multicomponent model membranes. This association mechanism is mainly characterized by interactions of gH with the extracellular solvent and the polar membrane surface. At the same time, the NP core interacts with the transmembrane (cholesterol-rich) fatty phase.

Molecular Recognition by Gold Nanoparticle-Based Receptors as Defined through Surface Morphology and Pockets Fingerprint

Ligand shell-protected gold nanoparticles can form nanoreceptors that recognize and bind to specific molecules in solution, with numerous potential innovative applications in science and industry. At this stage, the challenge is to rationally design such nanoreceptors to optimize their performance and boost their further development. Toward this aim, we have developed a new computational tool, Nanotron. This allows the analysis of molecular dynamics simulations of ligand shell-protected nanoparticles to define their exact surface morphology and pocket fingerprints of binding cavities in the coating monolayer. Importantly, from dissecting the well-characterized pairing formed by the guest salicylate molecule and specific host nanoreceptors, our work reveals that guest binding at such nanoreceptors occurs via preformed deep pockets in the host. Upon the interaction with the guest, such pockets undergo an induced-fit-like structural optimization for best host-guest fitting. Our findings and methodological advancement will accelerate the rational design of new-generation nanoreceptors.

Bowel contrast-enhanced ultrasound perfusion imaging in the evaluation of Crohn's disease patients undergoing anti-TNFα therapy

AIM

To evaluate whether changes in bowel perfusion parameters measured by dynamic-CEUS (D-CEUS) can be used for monitoring response to therapy in active Crohn disease (CD).

METHODS

Fifty-four CD patients were evaluated with d-CEUS before (T0) and after 2 (T1), 6 (T2) and 12 weeks (T3) of anti-TNFα therapy. Variations from baseline were calculated for: peak intensity, PI; area under the curve, AUC; slope of wash in, P_w; time to peak, TP; mean transit time, MTT (median percentage values) and were correlated with combined endoscopic/clinical response after 12 weeks and clinical relapse within 6 months.

RESULTS

70% of patients achieved combined endoscopic/clinical response (responders). The reduction in PI, AUC, P_w and MTT between T1 and T0 was higher in responders. Relapsers (21%) showed significantly lower reduction in delta PI and P_w at T1 and T2. At T3 they showed a new increase in PI and lower reduction in delta P_w. In relapsers, AUC showed a significantly lower decrease at T2 and T3, TP showed a significant reduction at T3 and MTT showed a progressive increase at the different time-points, reaching the statistical significance at T3.

CONCLUSIONS

d-CEUS might become a reliable predictor of combined endoscopic/clinical response and clinical relapse in CD.

The role of elastography in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide and its prevalence is even higher in patients with risk factors such as type 2 diabetes and obesity. Liver biopsy is the gold standard for diagnosis of non-alcoholic steatohepatitis (NASH), particularly for the assessment of fibrosis stage that is a key prognostic factor. Noninvasive methods for assessment of liver fibrosis are a huge need in contemporary hepatology in order to stratify patient's risk of advanced and progressive liver disease. In this perspective different imaging techniques have been developed in last decades and showed high performance in liver fibrosis evaluation. Strengths and weaknesses of all imaging methods are summarized in this review.

A Gold Nanoparticle Nanonuclease Relying on a Zn(II) Mononuclear Complex

Similarly to enzymes, functionalized gold nanoparticles efficiently catalyze chemical reactions, hence the term nanozymes. Herein, we present our results showing how surface-passivated gold nanoparticles behave as synthetic nanonucleases, able to cleave pBR322 plasmid DNA with the highest efficiency reported so far for catalysts based on a single metal ion mechanism. Experimental and computational data indicate that we have been successful in creating a catalytic site precisely mimicking that suggested for natural metallonucleases relying on a single metal ion for their activity. It comprises one Zn(II) ion to which a phosphate diester of DNA is coordinated. Importantly, as in nucleic acids-processing enzymes, a positively charged arginine plays a key role by assisting with transition state stabilization and by reducing the pKa of the nucleophilic alcohol of a serine. Our results also show how designing a catalyst for a model substrate (bis-p-nitrophenylphosphate) may provide wrong indications as for its efficiency when it is tested against the real target (plasmid DNA).

Assessing Baveno VI criteria with liver stiffness measured using a new point-shear wave elastography technique (BAVElastPQ study)

BACKGROUND AND AIMS

To date, no study has explored the potential role of ElastPQ, a novel point-SWE technique, in the assessment of clinically significant portal hypertension. The aim of our study was to determine a liver stiffness (LS) cut-off value measured by ElastPQ and laboratory parameters that could help to identify those patients who can safely avoid screening endoscopy.

METHODS

Data were collected on 1422 patients who underwent ElastPQ measurement from January 2013 to January 2016 in our Department. Inclusion criteria were a LS value of ≥7 kPa, an upper gastrointestinal endoscopy within 12 months and a diagnosis of compensated chronic liver disease. Exclusion criteria were history of decompensated liver disease, evidence of porto-spleno-mesenteric vein thrombosis and non-cirrhotic portal hypertension. Varices were graded as low-risk varices (grade <2) or varices needing treatment (VNT, grade ≥2).

RESULTS

The study included 195 patients (120 [61%] HCV, 171 [88%] Child-Pugh A). Varices were present in 35% cases, with 10% prevalence of VNT. According to ROC curve analysis, LS measurement and platelet count were evaluated as predictors of VNT. Overall, 75/195 (38%) met the 'BAVElastPQ' criteria (that is, LS < 12 kPa and platelet count >150 000/μL). Within this group, 11/75 (15%) had any grade of varices and only 1/75 (1%) had VNT. The BAVElastPQ criteria gave sensitivity of 0.95, specificity of 0.42, positive predictive value of 0.15 and negative predictive value of 0.99.

CONCLUSIONS

The BAVElastPQ criteria correctly identified 99% of patients without VNT. By applying such criteria, we could have potentially avoided 38% of surveillance endoscopies in our cohort.

Recurrent hepatocellular carcinoma and non-classic adreno-genital syndrome

OBJECTIVE

Hepatocellular carcinoma (HCC) is one of the most common fatal cancer in the world and androgens are among the possible etiological factors. Congenital adrenal hyperplasia (CAH) is a group of inherited diseases caused by enzyme failure in the steroid biosynthesis of the adrenal cortex, resulting in an augmented 17-hydroxyprogesterone, androstenedione and testosterone production. While the occurrence of testicular adrenal rest tumors and adrenocortical tumors in congenital adrenal hyperplasia is well described in the literature, no data on HCC occurrence are available.

CASE PRESENTATION

A 35-years-old Italian man of Caucasian origin, affected by non-classic CAH due to partial 21-hydroxylase deficiency came to observation for revaluation of his adrenal picture. Besides common hormonal and biochemical analysis, an abdomen Magnetic Resonance Imaging was performed, resulting in an 18 mm large nodular lesion between liver segments VII and VIII. Radiological reports matched with an increased serum α-fetoprotein level. A surgical removal of the lesion was performed. After that, several recurrences of the lesion, which was consequently treated by radiofrequency ablation, occurred. Every recurrence was accompanied by an increase in testosterone and steroid hormone binding globulin serum levels.

CONCLUSIONS

Our report suggests the need for screening of liver lesions in males affected by this syndrome.

Contrast-Enhanced Ultrasound in the Short-Term Evaluation of Hepatocellular Carcinoma after Locoregional Treatment

BACKGROUND

Contrast-enhanced ultrasound (CEUS) with second-generation contrast agents performed 1 month after hepatocellular carcinoma (HCC) treatment is almost as sensitive as contrast-enhanced computed tomography (CECT) in depicting the residual tumor. However, the efficacy of CEUS performed early after the procedure is still debated.

AIM

We evaluated the diagnostic accuracy (DA) of CEUS for the assessment of tumor response shortly after locoregional therapy in patients with unresectable HCC.

METHODS

Ninety-four patients with 104 HCC lesions who were scheduled to receive percutaneous ethanol injection, radiofrequency ablation, transcatheter arterial chemoembolization, or combined treatment were enrolled in this study. With CECT at 1-month as the reference standard, the DA of CEUS performed 48-h after the procedure was evaluated. Patients were followed-up to look for tumor or disease progression.

RESULTS

Based on CECT findings, 43/104 lesions were diagnosed as having residual viability after 1 month. CEUS performed 48 h after treatment detected residual tumor in 34/43 nodules with treatment failure at CECT with a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 79.1, 96.7, 94.4, 86.8, and 89%, respectively. There was a high degree of concordance between CEUS and CECT (kappa coefficient = 0.78). A hyperemic halo was detectable in 35 lesions without a statistically significant difference between concordant and discordant cases. In patients with uninodular disease responders according to 48 h CEUS had a significantly longer mean overall survival and time to progression compared to nonresponders.

CONCLUSION

CEUS performed 48 h after treatment can be considered a reliable modality for the evaluation of the real extent of necrosis and has prognostic value in the assessment of HCC.

Structure and Dynamics of the Acyl Chains in the Membrane Trafficking and Enzymatic Processing of Lipids

The regulatory chemical mechanisms of lipid trafficking and degradation are involved in many pathophysiological processes, being implicated in severe pain, inflammation, and cancer. In addition, the processing of lipids is also relevant for industrial and environmental applications. However, there is poor understanding of the chemical features that control lipid membrane trafficking and allow lipid-degrading enzymes to efficiently select and hydrolyze specific fatty acids from a complex cellular milieu of bioactive lipids. This is particularly true for lipid acyl chains, which have diverse structures that can critically affect the many complex reactions needed to elongate, desaturate, or transport fatty acids. Building upon our own contributions in this field, we will discuss how molecular simulations, integrated with experimental evidence, have revealed that the structure and dynamics of the lipid tail are actively involved in modulating membrane trafficking at cellular organelles, and enzymatic reactions at cell membranes. Further evidence comes from recent crystal structures of lipid receptors and remodeling enzymes. Taken together, these recent works have identified those structural features of the lipid acyl chain that are crucial for the regioselectivity and stereospecificity of essential desaturation reactions. In this context, we will first illustrate how atomistic and coarse-grained simulations have elucidated the structure-function relationships between the chemical composition of the lipid's acyl chains and the molecular properties of lipid bilayers. Particular emphasis will be given to the prominent chemical role of the number of double carbon-carbon bonds along the lipid acyl chain, that is, discriminating between saturated, monounsaturated, and polyunsaturated lipids. Different levels of saturation in fatty acid molecules dramatically influence the biophysical properties of lipid assemblies and their interaction with proteins. We will then discuss the processing of lipids by membrane-bound enzymes. Our focus will be on lipids such as anandamide and 2-arachidonoylglycerol. These are the main molecules that act as neurotransmitters in the endocannabinoid system. Specifically, recent findings indicate a crucial interplay between the level of saturation of the lipid tail, its energetically and sterically favored conformations, and the hydrophobic accessory cavities in lipid-degrading enzymes, which help form catalytically active conformations of the selected substrate. This Account will emphasize how the specific chemical structure of acyl chains affects the molecular mechanisms for modulating membrane trafficking and selective hydrolysis. The results examined here show that, by using molecular simulations to investigate lipid plasticity and substrate flexibility, researchers can enrich their interpretation of experimental results about the structure-function relationships of lipids. This could positively impact chemical and biological studies in the field and ultimately support protein engineering studies and structure-based drug discovery to target lipid-processing enzymes.

Portal vein thrombosis in cirrhosis: Why a well-known complication is still matter of debate

Portal vein thrombosis (PVT) represents a well-known complication during the natural course of liver cirrhosis (LC), ranging from asymptomatic cases to life-threating conditions related to portal hypertension and hepatic decompensation. Portal flow stasis, complex acquired hypercoagulable disorders and exogenous factors leading to endothelial dysfunction have emerged as key factors for PVT development. However, PVT occurrence remains unpredictable and many issues regarding its natural history, prognostic significance and treatment are still elusive. In particular although spontaneous resolution or disease stability occur in most cases of PVT, factors predisposing to disease progression or recurrence after spontaneous recanalization are not clarified as yet. Moreover, PVT impact on LC outcome is still debated, as PVT may represent itself a consequence of liver fibrosis and hepatic dysfunction progression. Anticoagulation and transjugular intrahepatic portosystemic shunt are considered safe and effective in this setting and are recommended in selected cases, even if the safer therapeutic option and the optimal therapy duration are still unknown. Nevertheless, their impact on mortality rates should be addressed more extensively. In this review we present the most debated questions regarding PVT, whose answers should come from prospective cohort studies and large sample-size randomized trials.

Dynamic Origin of Chirality Transfer between Chiral Surface and Achiral Ligand in Au38 Clusters

The transfer of chirality between nanomolecules is at the core of several applications in chiral technology such as sensing and catalysis. However, the origin of this phenomenon and how exactly nanoscale objects transfer chirality to molecules in their vicinity remain largely obscure. Here, we show that the transfer of chirality for the intrinsically chiral gold cluster Au₃₈(SR)₂₄ is site dependent; that is, it differs depending on the ligand-binding sites. This is closely related to the dynamic nature of the ligands on the cluster surface. Using a combination of NMR techniques and molecular dynamics simulations, we could assign the four symmetry-unique ligands on the cluster. The study reveals largely different conformational dynamics of the bound ligands, explaining the diverse diastereotopicities observed for the CH₂ protons of the ligands. Although chirality is a structural property, our study reveals the importance of dynamics for the transfer of chirality.

Molecular-Dynamics-Simulation-Directed Rational Design of Nanoreceptors with Targeted Affinity

Here, we demonstrate the possibility of rationally designing nanoparticle receptors with targeted affinity and selectivity for specific small molecules. We used atomistic molecular-dynamics (MD) simulations to gradually mutate and optimize the chemical structure of the molecules forming the coating monolayer of gold nanoparticles (1.7 nm gold-core size). The MD-directed design resulted in nanoreceptors with a 10-fold improvement in affinity for the target analyte (salicylate) and a 100-fold decrease of the detection limit by NMR-chemosensing from the millimolar to the micromolar range. We could define the exact binding mode, which features prolonged contacts and deep penetration of the guest into the monolayer, as well as a distinct shape of the effective binding pockets characterized by exposed interacting points.

NanoModeler: A Webserver for Molecular Simulations and Engineering of Nanoparticles

Functionalized nanoparticles (NPs) are at the frontier of nanoscience. They hold the promise of innovative applications for human health and technology. In this context, molecular dynamics (MD) simulations of NPs are increasingly employed to understand the fundamental structural and dynamical features of NPs. While informative, such simulations demand a laborious two-step process for their setup. In-house scripts are required to (i) construct complex 3D models of the inner metal core and outer layer of organic ligands, and (ii) correctly assign force-field parameters to these composite systems. Here, we present NanoModeler ( www.nanomodeler.it ), the first Webserver designed to automatically generate and parametrize model systems of monolayer-protected gold NPs and gold nanoclusters. The only required input is a structure file of one or two ligand(s) to be grafted onto the gold core, with the option of specifying homogeneous or heterogeneous NP morphologies. NanoModeler then generates 3D models of the nanosystem and the associated topology files. These files are ready for use with the Gromacs MD engine, and they are compatible with the AMBER family of force fields. We illustrate NanoModeler's capabilities with MD simulations of selected representative NP model systems. NanoModeler is the first platform to automate and standardize the construction and parametrization of realistic models for atomistic simulations of gold NPs and gold nanoclusters.

Congenital extrahepatic portosystemic shunt: description of four cases and review of the literature

Congenital extrahepatic portosystemic shunt (CEPS), also known as Abernethy malformation, is a rare condition in which the splenomesenteric blood drains directly into a systemic vein, bypassing the liver through a complete or partial shunt. The diagnosis is frequently made during childhood in the setting of neonatal cholestasis, hypergalactosemia, failure to thrive, mental retardation or other congenital defects. In adulthood, CEPS is usually found incidentally during diagnostic work-up for abdominal pain, liver test abnormalities, liver nodules, portopulmonary hypertension, portopulmonary syndrome or portosystemic encephalopathy. The diagnosis depends on imaging and portal venography, but sometimes only liver biopsy can be resolutive, demonstrating the absence of venules within the portal areas. Here we report four recent cases of Abernethy malformation diagnosed in young adults, in which ultrasound (US) was the initial imaging technique and allowed to suspect the diagnosis. Furthermore, we reviewed clinical presentations, associated anomalies and treatment of the 310 cases of CEPS previously reported in the literature.

Contrast-enhanced ultrasound patterns of hepatocellular adenoma: an Italian multicenter experience

PURPOSE

Hepatocellular adenoma (HCA) is a rare benign monoclonal neoplasm, recently categorized on genetic and histopathological basis into four subtypes with different biological behaviors. Since contrast-enhanced ultrasonography (CEUS) is nowadays a well-established technique for liver nodule characterization, the aim of our study was to assess CEUS features of HCAs to identify criteria that correlate with different HCA subtypes as compared to histopathologic examination and other imaging modalities.

METHODS

We retrospectively analyzed data of patients with histology-proven HCA who underwent CEUS, computed tomography or magnetic resonance imaging (MRI) in seven different Italian ultrasound units.

RESULTS

The study enrolled 19 patients (16 females; 69% with concomitant/prior use of oral contraceptives): the mean size of all HCAs was 4.2 cm (range 1.6-7.1 cm); 14/19 had inflammatory HCAs (I-HCA), 1/19 β-catenin-activated HCA, and the others unclassified HCAs. On CEUS, during the arterial phase, all but one HCA displayed a rapid enhancement, with 89% of these showing centripetal and 11% centrifugal filling pattern, whereas during the portal and late venous phase 58% of HCA showed washout and the remaining 42% displayed persistent enhancement. In particular, among I-HCAs 7/14 showed no washout, 3/14 and 4/14 showed washout in the portal or late phase, respectively.

CONCLUSIONS

This dataset represents one of the few published experiences on HCAs and CEUS in Italy and shows that HCAs are hypervascularized in the arterial phase usually with a centripetal flow pattern and have a heterogeneous behavior in portal and late phase. In particular, occurrence of delayed washout on CEUS but not on MRI is frequently observed in the subtype of I-HCA.

Abietane-Type Diterpenoids Inhibit Protein Tyrosine Phosphatases by Stabilizing an Inactive Enzyme Conformation

Protein tyrosine phosphatases (PTPs) contribute to a striking variety of human diseases, yet they remain vexingly difficult to inhibit with uncharged, cell-permeable molecules; no inhibitors of PTPs have been approved for clinical use. This study uses a broad set of biophysical analyses to evaluate the use of abietane-type diterpenoids, a biologically active class of phytometabolites with largely nonpolar structures, for the development of pharmaceutically relevant PTP inhibitors. Results of nuclear magnetic resonance analyses, mutational studies, and molecular dynamics simulations indicate that abietic acid can inhibit protein tyrosine phosphatase 1B, a negative regulator of insulin signaling and an elusive drug target, by binding to its active site in a non-substrate-like manner that stabilizes the catalytically essential WPD loop in an inactive conformation; detailed kinetic studies, in turn, show that minor changes in the structures of abietane-type diterpenoids (e.g., the addition of hydrogens) can improve potency (i.e., lower IC₅₀) by 7-fold. These findings elucidate a previously uncharacterized mechanism of diterpenoid-mediated inhibition and suggest, more broadly, that abietane-type diterpenoids are a promising source of structurally diverse-and, intriguingly, microbially synthesizable-molecules on which to base the design of new PTP-inhibiting therapeutics.