In vivo label-free quantification of liver microcirculation using dual-modality microscopy

Proof of Concept: Super-Resolution Ultrasound and Viscoelastic Imaging of Hepatic Microcirculation for Early Detection and Staging of Liver Fibrosis in a Murine Model

OBJECTIVES

Super-resolution ultrasound microvascular imaging (SRUS) has emerged as a noninvasive technology capable of visualizing the microvasculature with exceptional spatial resolution, surpassing the acoustic diffraction limit. This study aims to assess the potential of SRUS in staging liver fibrosis by evaluating its diagnostic performance against ultrasound viscosity imaging.

METHODS

Liver fibrosis was induced by carbon tetrachloride (CCl4) in 30 mice. The mice were evenly distributed across five stages (6 mice per stage), categorized from F0 (no fibrosis) to F4 (cirrhosis) based on the extent of collagen deposition. SRUS microvascular imaging and ultrasound viscosity imaging were compared for their efficacy in detecting liver fibrosis stages. Immunohistochemistry and histopathological analyses were conducted to correlate vessel density and collagen deposition.

RESULTS

SRUS effectively detected microvascular changes across all fibrosis stages. Significant vessel diameter enlargement was observed at early stages (F1), with further increases in advanced stages (F3-F4). Vessel density significantly decreased in later stages, indicating compromised angiogenesis. Ultrasound viscosity imaging showed marked viscoelastic reductions in fibrosis but lacked sensitivity in early-stage detection. SRUS parameters exhibited strong correlations with histological findings, underscoring their potential diagnostic value. Receiver operating characteristic (ROC) curve analysis further demonstrated the superior sensitivity of SRUS (89.59% [95% confidence interval (CI): 84.87-92.96%]), particularly in distinguishing early-stage fibrosis (F0-F1) from advanced stages (F2-F4) (area under the curve [AUC] = 0.9610, 95% CI: 0.9449-0.9771; P < .001).

CONCLUSIONS

SRUS microvascular imaging is a promising adjunct to traditional elastography, offering enhanced sensitivity for early-stage liver fibrosis detection. It provides critical insights into microcirculatory dysfunction, complementing stiffness measurements and aiding in accurate diagnosis.

Exogenous Volatile Organic Compound (EVOC®) Breath Testing Maximizes Classification Performance for Subjects with Cirrhosis and Reveals Signs of Portal Hypertension

Background: Cirrhosis detection in primary care relies on low-performing biomarkers. Consequently, up to 75% of subjects with cirrhosis receive their first diagnosis with decompensation when causal treatments are less effective at preserving liver function. We investigated an unprecedented approach to cirrhosis detection based on dynamic breath testing. Methods: We enrolled 29 subjects with cirrhosis (Child-Pugh A and B), and 29 controls. All subjects fasted overnight. Breath samples were taken using Breath Biopsy® before and at different time points after the administration of 100 mg limonene. Absolute limonene breath levels were measured using gas chromatography-mass spectrometry. Results: All subjects showed a >100-fold limonene spike in breath after administration compared to baseline. Limonene breath kinetics showed first-order decay in >90% of the participants, with higher bioavailability in the cirrhosis group. At the Youden index, baseline limonene levels showed classification performance with an area under the roc curve (AUROC) of 0.83 ± 0.012, sensitivity of 0.66 ± 0.09, and specificity of 0.83 ± 0.07. The best performing timepoint post-administration was 60 min, with an AUROC of 0.91, sensitivity of 0.83 ± 0.07, and specificity of 0.9 ± 0.06. In the cirrhosis group, limonene bioavailability showed a correlation with MELD and fibrosis indicators, and was associated with signs of portal hypertension. Conclusions: Dynamic limonene breath testing enhances diagnostic performance for cirrhosis compared to static testing. The correlation with disease severity suggests potential for monitoring therapeutic interventions. Given the non-invasive nature of breath collection, a dynamic limonene breath test could be implemented in primary care.

Association of the Collagen Signature in the Tumor Microenvironment With Recurrence and Survival of Patients With T4N0M0 Colon Cancer

BACKGROUND

The current clinicopathological risk factors do not accurately predict disease recurrence in patients with T4N0M0 colon cancer. We hypothesized that the collagen signature combined with clinicopathological risk factors (new model) had a better prognostic value than clinicopathological risk factors alone (clinicopathological model).

OBJECTIVE

This study aimed to establish a collagen signature in the tumor microenvironment and to validate its role in predicting the recurrence of T4N0M0 colon cancer.

DESIGN

This was a retrospective study.

SETTINGS

This study took place at a tertiary medical center.

PATIENTS

Patients with T4N0M0 colon cancer who underwent surgery at our center between 2009 and 2015 (n = 416) were included.

INTERVENTION

A total of 142 collagen features were analyzed in the tumor microenvironment in specimens of colon cancer by using second-harmonic generation imaging. A collagen signature was constructed using a least-absolute shrinkage and selection operator Cox regression model.

MAIN OUTCOME MEASURES

The primary outcomes measured were disease-free survival and overall survival.

RESULTS

The training and testing cohorts consisted of 291 and 125 randomly assigned samples, with recurrence rates of 19.9% and 22.4%. A 3-feature-based collagen signature predicted the recurrence risk at 1, 3, and 5 years, with the area under the receiver-operating characteristic curves of 0.808, 0.832, and 0.791 in the training cohort and 0.836, 0.807, and 0.794 in the testing cohort. Multivariate analysis revealed that the collagen signature could independently predict the disease-free survival (HR = 7.17, p < 0.001) and overall survival rates (HR = 5.03, p < 0.001). The new model had a better prognostic value than the clinicopathological model, which included 4 clinicopathological risk factors: obstruction or perforation, lymphovascular invasion, tumor budding, and no chemotherapy.

LIMITATIONS

This study was limited by its retrospective design.

CONCLUSIONS

The collagen signature in the tumor microenvironment may be a new prognostic marker that can effectively predict the recurrence and survival of patients with T4N0M0 colon cancer. See Video Abstract at http://links.lww.com/DCR/B503. ASOCIACIÓN DE LA RÚBRICA DE COLÁGENO EN EL MICROAMBIENTE TUMORAL CON LA RECIDIVA Y LA SOBREVIDA DE PACIENTES CON CÁNCER DE COLON T4N0M0: Los factores de riesgo clínico-patológicos actuales no predicen con precisión la recurrencia de la enfermedad en pacientes con cáncer de colon estadío T4N0M0. Presumimos que la rúbrica de colágeno combinada con factores de riesgo clínico-patológicos (nuevo modelo) tendrían un mejor valor pronóstico que los factores de riesgo clínico-patológicos solos (modelo clínico-patológico).El establecer una rúbrica de colágeno en el microambiente tumoral y validar su papel en la predicción de la recidiva del cáncer de colon T4N0M0.Estudio retrospectivo.Investigación llevada a cabo en un centro médico terciario.Se incluyeron pacientes con cáncer de colon T4N0M0 operados en nuestro centro entre 2009 y 2015 (n = 416).Se analizaron un total de 142 características de colágeno en el microambiente tumoral en muestras de cáncer de colon utilizando imágenes de segunda generación armónica. Se construyó una rúbrica de colágeno utilizando un modelo de regresión LASSO Cox.Sobrevida libre de enfermedad y sobrevida global.Las cohortes de entrenamiento y prueba consistieron en 291 y 125 muestras asignadas al azar, con tasas de recurrencia del 19,9% y 22,4%, respectivamente. La rúbrica del colágeno basada en 3 características predijo el riesgo de recurrencia a 1, 3 y 5 años, con el área bajo las curvas características operativas del receptor de 0,808, 0,832 y 0,791 en la cohorte de entrenamiento y 0,836, 0,807 y 0,794 en la cohorte de prueba, respectivamente. El análisis multivariado reveló que la firma de colágeno podría predecir de forma independiente la supervivencia libre de enfermedad (HR = 7,17, p <0,001) y las tasas de sobrevida general (HR = 5,03, p <0,001). El nuevo modelo tuvo un mejor valor pronóstico que el modelo clínico-patológico, que incluyó cuatro factores de riesgo clínico-patológicos: obstrucción o perforación, invasión linfovascular, gemación tumoral y ausencia de quimioterapia.Este estudio estuvo limitado por su diseño retrospectivo.La rúbrica de colágeno en el microambiente tumoral puede ser un nuevo marcador pronóstico para predecir eficazmente la recurrencia y la subrevida de los pacientes con cáncer de colon T4N0M0. Consulte Video Resumen en http://links.lww.com/DCR/B503. (Traducción-Dr. Xavier Delgadillo).

Pathological Features of Mitochondrial Ultrastructure Predict Susceptibility to Post-TIPS Hepatic Encephalopathy

BACKGROUND

Post-TIPS hepatic encephalopathy (PSE) is a complex process involving numerous risk factors; the root cause is unclear, but an elevation of blood ammonia due to portosystemic shunt and metabolic disorders in hepatocytes has been proposed as an important risk factor.

AIMS

The aim of this study was to investigate the impact of pathological features of mitochondrial ultrastructure on PSE via transjugular liver biopsy at TIPS implantation.

METHODS

We evaluated the pathological damage of mitochondrial ultrastructure on recruited patients by the Flameng classification system. A score ≤2 (no or low damage) was defined as group A, and a score >2 (high damage level) was defined as group B; routine follow-up was required at 1 and 2 years; the incidence of PSE and multiple clinical data were recorded.

RESULTS

A total of 78 cases in group A and 42 in group B completed the study. The incidence of PSE after 1 and 2 years in group B (35.7% and 45.2%, respectively) was significantly higher than that in group A (16.7% and 24.4%, respectively); the 1- and 2-year OR (95% CI) were 2.778 (1.166-6.615) and 2.565 (1.155-5.696), respectively, for groups A and B. Importantly, group B had worse incidence of PSE than group A [P=0.014, hazard ratio (95%CI): 2.172 (1.190-4.678)].

CONCLUSION

Aggressive damage to mitochondrial ultrastructure in liver shunt predicts susceptibility to PSE. The registration number is NCT02540382.

Line-scan focal modulation microscopy

We report the development of a line-scan focal modulation microscope (LSFMM) that is capable of high-speed image acquisition ( > 40 ?? fps ) with uncompromised optical sectioning capability. The improved background rejection and axial resolution of this imaging modality, enabled by focal modulation, are quantified with three-dimensional imaging data obtained from fluorescent beads. The signal-to-background ratio for the LSFMM system is one- to two-orders of magnitude higher than that for line-scanning confocal systems when imaging deep (up to 100 ?m) into a turbid medium of optical properties similar to biological tissues. The imaging performance of LSFMM, in terms of both spatial and temporal resolutions, is further demonstrated with in vivo imaging experiments with live zebrafish larvae.

In vivo imaging of hepatic hemodynamics and light scattering property during ischemia-reperfusion in rats based on spectrocolorimetry

A red-green-blue camera-based imaging method is proposed for estimating spatial maps of concentrations of oxyhemoglobin (CHbO), deoxyhemoglobin (CHbR), total hemoglobin (CHbT), tissue oxygen saturation (StO2), and scattering power (b) in liver tissue. Hemodynamic responses to hepatic ischemia-reperfusion of in vivo rat liver tissues induced by portal triad occlusion were evaluated. Upon portal triad occlusion, this method yielded images of decreased CHbO, CHbT, StO2, and b, and increased CHbR followed by a progressive increase in CHbO and StO2 during reperfusion. Time courses of the changes in CHbO, CHbR, CHbT, and StO2 over different regions of interest (ROIs) revealed that ischemia results in an abrupt significant (P<0.05) reduction in CHbO, CHbT, and StO2 with a simultaneous increase in CHbR compared to the baseline level, indicative of the hemodynamic responses during hepatic ischemia-reperfusion. Upon reperfusion, there was a gradual increase in CHbO and StO2, and decrease in CHbR. The change in average scattering power b implies the presence of morphological alterations in the cellular and subcellular structures induced by ischemia or anoxia. This study shows the potential of monitoring spatiotemporal changes in hemodynamic parameters and morphological changes in studies of hepatic pathophysiology.