Current use and perspective of indocyanine green clearance in liver diseases

Fluorescence Imaging Using Deep-Red Indocyanine Blue, a Complementary Partner for Near-Infrared Indocyanine Green

Indocyanine Blue (ICB) is the deep-red pentamethine analogue of the widely used clinical near-infrared heptamethine cyanine dye Indocyanine Green (ICG). The two fluorophores have the same number of functional groups and molecular charge and vary only by a single vinylene unit in the polymethine chain, which produces a predictable difference in spectral and physicochemical properties. We find that the two dyes can be employed as a complementary pair in diverse types of fundamental and applied fluorescence imaging experiments. A fundamental fluorescence spectroscopy study used ICB and ICG to test a recently proposed Förster Resonance Energy Transfer (FRET) mechanism for enhanced fluorescence brightness in heavy water (D2O). The results support two important corollaries of the proposal: (a) the strategy of using heavy water to increase the brightness of fluorescent dyes for microscopy or imaging is most effective when the dye emission band is above 650 nm, and (b) the magnitude of the heavy water florescence enhancement effect for near-infrared ICG is substantially diminished when the ICG surface is dehydrated due to binding by albumin protein. Two applied fluorescence imaging studies demonstrated how deep-red ICB can be combined with a near-infrared fluorophore for paired agent imaging in the same living subject. One study used dual-channel mouse imaging to visualize increased blood flow in a model of inflamed tissue, and a second mouse tumor imaging study simultaneously visualized the vasculature and cancerous tissue in separate fluorescence channels. The results suggest that ICB and ICG can be incorporated within multicolor fluorescence imaging methods for perfusion imaging and hemodynamic characterization of a wide range of diseases.

Change of indocyanine green clearance ability and liver function after transcatheter intra-arterial therapies and its impact on outcomes of resectable hepatocellular carcinoma: a retrospective cohort study

BACKGROUND

Indocyanine green (ICG) clearance test is a classical measurement of hepatic reserve, which involves surgical safety and patient recovery of hepatocellular carcinoma (HCC). The authors aim to compare effects of hepatic arterial infusion chemotherapy (HAIC) and transcatheter arterial chemoembolization (TACE) on liver function and outcomes of subsequent hepatectomy.

MATERIAL AND METHODS

HCC patients receiving HAIC/TACE in SYSUCC with repeated ICG clearance tests were retrospectively enrolled. ICG eliminating rate (ICG-K), ICG retention rate at 15 min (ICG-R15) and ordinary laboratory tests were collected. Peri-therapeutic changes of values were compared between the groups. Propensity score matching (PSM) and inverse probability of treatment weighing (IPTW) were employed to validate findings. Post-hepatectomy liver failure (PHLF), overall survival (OS) and recurrence-free survival (RFS) were analyzed in patients with subsequent curative hepatectomy.

RESULTS

Two hundred and four patients treated with HAIC ( n =130) and TACE ( n =74) were included. ΔICG-R15 was greater in the HAIC arm before matching (mean, 3.8% vs. 0.7%, P <0.001), after PSM (mean, 4.7% vs. 1.1%, P =0.014) and IPTW (mean, 2.0% vs. -3.6%, P <0.001). No difference was found for ΔALB, ΔALBI, ΔTBIL, ΔALT, ΔAST and ΔPT-INR. Multivariable analyses revealed elder age, cirrhosis, HAIC, greater ΔTBIL and ΔALBI were associated with deteriorating ICG-R15. Among those (105 for HAIC and 48 for TACE) receiving hepatectomy, occurrence of grade B/C PHLF (4.8% vs. 8.3%, P =0.616), OS (median, unreached vs. unreached, P =0.94) and RFS (median, 26.7 vs. 17.1 months, P =0.096) were comparable between the two arms. In subgroup analyses, preoperative HAIC yield superior RFS (median, 26.7 vs. 16.2 months, P =0.042) in patients with baseline ICG-R15 less than or equal to 10%.

CONCLUSION

Preoperative FOLFOX-HAIC caused apparent impairment of ICG clearance ability than TACE yet comparable impact on liver function and post-hepatectomy outcomes.

Comparison of the efficacy of the gadoxetic acid MRI-derived relative enhancement index (REI) and functional liver imaging score (FLIS) in predicting liver function: validation with Albumin-Bilirubin (ALBI) grade

PURPOSE

This study compared the predictive performance of the relative enhancement index (REI) derived from gadoxetic acid (GA)-enhanced MRI with that of the functional liver imaging score (FLIS) in estimating liver function among patients with chronic liver disease (CLD) or liver cirrhosis (LC) by validating them with the albumin-bilirubin (ALBI) grade.

MATERIALS AND METHODS

We retrospectively examined 166 patients (79 women, 87 men; 57.4 years) who were diagnosed with LC or CLD and underwent GA-enhanced MRI between August 2020 and September 2023. The enhancement ratio (ER) is calculated using the formula: ER = [hepatobiliary phase liver signal (SI HBP20)-precontrast liver signal (SI pre)]/SI pre. The REI is calculated using the formula: REI = Liver Volume (LV) × ER. FLIS was assigned from the sum of three HBP image features, each scored between 0 and 2: liver parenchymal enhancement, biliary contrast excretion, and portal vein sign. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff values of ER, REI, and FLIS in differentiating between ALBI grades. The area under the curve (AUC), accuracy, sensitivity, and specificity were calculated for REI and FLIS to distinguish the ALBI grades. Spearman's rank correlation was used to evaluate the ER, REI, and FLIS correlations between the ALBI grades. To evaluate inter-reader reliability for LV, ER, REI, and FLIS, intraclass correlation coefficient (ICC) was used.

RESULTS

ROC curve analysis showed that the optimal cutoff value of REI for predicting ALBI Grade 1 was 899-905 for readers 1 and 2 and 461-477 for ALBI Grade 3, respectively. REI performed best in predicting ALBI Grade 1, achieving an accuracy range of 94%-92.2%, sensitivity of 94.9%-94.1%, and specificity of 91.7%-87.5% for readers 1 and 2, respectively. All parameters showed high accuracy in distinguishing ALBI Grade 3 from other grades. However, REI outperformed the others, showing an accuracy range of 98.8%-97.6%, sensitivity of 94.4%-94.4%, and specificity of 99.3%-98% for readers 1 and 2, respectively. REI showed the best and very strong correlation with ALBI for both readers.

CONCLUSION

REI showed a very strong correlation with the ALBI grades for assessing liver function. It outperformed FLIS in predicting the ALBI grades, indicating its potential as a radiologic tool comparable to or better than FLIS in predicting liver function, especially given its dependence on liver volume.

Indocyanine green: A novel marker for assessment of graft quality during ex situ normothermic machine perfusion of human livers

BACKGROUND

Ex situ machine perfusion facilitates the assessment of livers prior to transplantation. However, currently available markers of liver function poorly predict long-term graft function. Indocyanine green (ICG) is a liver-specific dye which, although common in vivo, has never been comprehensively evaluated for the assessment of graft quality during ex situ machine perfusion. This study aimed to assess the utility of ICG in the ex situ setting.

METHODS

Using a customized long-term perfusion system, human livers that were not suitable for transplantation were perfused using a red cell-based perfusate. ICG was delivered into the perfusate on days 0, 1, and 4 to assess ICG clearance (spectrophotometric absorbance at 805 nm) and ICG fluorescence (near-infrared camera).

RESULTS

Sixteen partial livers were perfused for a median duration of 172 h (7.2 days). On day 0, the median ICG perfusate disappearance rate (PDR) was 7.5%/min and the median ICG retention at 15 min was 9.9%. Grafts that survived ≥7 days had a significantly higher median ICG PDR on day 0 (14.5%/min vs. 6.5%/min, p = 0.005) but not on days 1 or 4. ICG perfusion demonstrated that long-surviving grafts had a significantly lower median red-value (89.8 vs. 118.6, p = 0.011) and a significantly lower median blue-value (12.9 vs. 22.6, p = 0.045) than short-surviving grafts.

CONCLUSION

ICG is a novel marker for the assessment of liver function during ex situ normothermic machine perfusion. ICG PDR and quantitative ICG perfusion can distinguish between long- and short-surviving grafts and demonstrate the utility of ICG in the assessment of graft quality prior to transplant.

Indocyanine green clearance tests to assess liver transplantation outcomes: a systematic review

BACKGROUND

Liver transplantation (LT) is the gold standard for end-stage liver disease, yet postoperative complications challenge patients and physicians. Indocyanine green (ICG) clearance, a quantitative dynamic test of liver function, is a rapid, reproducible, and reliable test of liver function. This study aimed to systematically review and summarize current literature analyzing the association between ICG tests and post-LT outcomes.

METHODS

This systematic review was conducted according to PRISMA guidelines. MEDLINE and Cochrane Library, as main databases, and other sources were searched until August 2022 to identify articles reporting the prognostic value of postoperative ICG tests associated with outcomes of adult LT recipients.Risk of bias of included articles was assessed using Quality In Prognosis Studies tool. Methodological quality varied from low to high across risk of bias domains.

RESULTS

Six studies conducted between 1994 and 2018 in Europe, America, and Asia were included. The study population ranged from 50 to 332 participants. ICG clearance on the first postoperative day was associated with early allograft dysfunction, graft loss, 1-month and 3-month patient survival probability, prolonged ICU, and hospital stay. The dichotomized ICG plasma disappearance rate (PDR) provided a strong association with medium-term and long-term outcomes: PDR less than 10%/min with 1-month mortality or re-transplantation (odds ratio: 7.89, 95% CI 3.59-17.34, P <0.001) and PDR less than 16.0%/min with 3-month patient survival probability (hazard ratio: 13.90, 95% CI 4.67-41.35, P <0.01). The preoperative model for end-stage liver disease and body mass index were independent prognostic factors for early allograft dysfunction, early complications, and prolonged ICU stay; post-LT prothrombin time and INR were independently associated with graft loss and bilirubin with a prolonged hospital stay.

CONCLUSION

This review shows that ICG clearance tests are associated with graft function recovery, suggesting that a potential prognostic role of ICG test, as an aid in predicting the post-LT course, could be considered.

Application of Nanoparticles in the Diagnosis of Gastrointestinal Diseases: A Complete Future Perspective

The diagnosis of gastrointestinal (GI) diseases currently relies primarily on invasive procedures like digestive endoscopy. However, these procedures can cause discomfort, respiratory issues, and bacterial infections in patients, both during and after the examination. In recent years, nanomedicine has emerged as a promising field, providing significant advancements in diagnostic techniques. Nanoprobes, in particular, offer distinct advantages, such as high specificity and sensitivity in detecting GI diseases. Integration of nanoprobes with advanced imaging techniques, such as nuclear magnetic resonance, optical fluorescence imaging, tomography, and optical correlation tomography, has significantly enhanced the detection capabilities for GI tumors and inflammatory bowel disease (IBD). This synergy enables early diagnosis and precise staging of GI disorders. Among the nanoparticles investigated for clinical applications, superparamagnetic iron oxide, quantum dots, single carbon nanotubes, and nanocages have emerged as extensively studied and utilized agents. This review aimed to provide insights into the potential applications of nanoparticles in modern imaging techniques, with a specific focus on their role in facilitating early and specific diagnosis of a range of GI disorders, including IBD and colorectal cancer (CRC). Additionally, we discussed the challenges associated with the implementation of nanotechnology-based GI diagnostics and explored future prospects for translation in this promising field.

Joint Methodology Based on Optical Densitometry and Dynamic Light Scattering for Liver Function Assessment

A pressing health problem, both in clinical and socio-economic terms, is the increase in the number of patients with liver damage caused by viral diseases (hepatitis), cancer, toxicological damage, or metabolic disorders. Liver function assessment is a complex task, for which various existing diagnostic methods are used. Unfortunately, they all have several limitations which frequently make prompt and accurate diagnosis impossible. The high level of disability and mortality caused by liver diseases makes the development of new liver diagnostic methods very urgent. In this paper, we describe a new joint methodology for studying liver function based on optical densitometry and dynamic light scattering. This will help to diagnose and predict the dynamics of liver function during treatment with greater efficiency, due to including in consideration the individual characteristics of the cardiovascular system and tissue metabolism. In this paper, we present a laboratory model of a combined sensor for optical densitometry and dynamic light scattering. We also developed special software for controlling the sensor and processing the recorded data. Modeling experiments and physical medical studies were carried out to adjust and calibrate the sensor and software. We also assessed the sensor resolution when registering the concentration of dye in the human body and the minimum measured flow rate.

Use of In Vivo Imaging and Physiologically-Based Kinetic Modelling to Predict Hepatic Transporter Mediated Drug-Drug Interactions in Rats

Gadoxetate, a magnetic resonance imaging (MRI) contrast agent, is a substrate of organic-anion-transporting polypeptide 1B1 and multidrug resistance-associated protein 2. Six drugs, with varying degrees of transporter inhibition, were used to assess gadoxetate dynamic contrast enhanced MRI biomarkers for transporter inhibition in rats. Prospective prediction of changes in gadoxetate systemic and liver AUC (AUCR), resulting from transporter modulation, were performed by physiologically-based pharmacokinetic (PBPK) modelling. A tracer-kinetic model was used to estimate rate constants for hepatic uptake (khe), and biliary excretion (kbh). The observed median fold-decreases in gadoxetate liver AUC were 3.8- and 1.5-fold for ciclosporin and rifampicin, respectively. Ketoconazole unexpectedly decreased systemic and liver gadoxetate AUCs; the remaining drugs investigated (asunaprevir, bosentan, and pioglitazone) caused marginal changes. Ciclosporin decreased gadoxetate khe and kbh by 3.78 and 0.09 mL/min/mL, while decreases for rifampicin were 7.20 and 0.07 mL/min/mL, respectively. The relative decrease in khe (e.g., 96% for ciclosporin) was similar to PBPK-predicted inhibition of uptake (97-98%). PBPK modelling correctly predicted changes in gadoxetate systemic AUCR, whereas underprediction of decreases in liver AUCs was evident. The current study illustrates the modelling framework and integration of liver imaging data, PBPK, and tracer-kinetic models for prospective quantification of hepatic transporter-mediated DDI in humans.

Relative enhancement index can be used to quantify liver function in cirrhotic patients that undergo gadoxetic acid-enhanced MRI

OBJECTIVES

To evaluate MRI with gadoxetic acid to quantify liver function in cirrhotic patients using the relative enhancement index (REI) compared with Child-Pugh score (CPS), MELD score, and indocyanine green plasma disappearance rate (ICG-PDR) and to establish cutoffs for REI to stratify cirrhotic patients into good and poor liver function groups.

METHODS

We prospectively evaluated 60 cirrhotic patients and calculated CPS, MELD score, ICG-PDR, and REI for each patient. Spearman's correlation coefficient was used to assess correlation between REI, CPS, MELD, and ICG-PDR. Good and poor liver function groups were created by k-means clustering algorithm using CPS, MELD, and ICG-PDR. ROC curve analysis was performed and optimal cutoff was identified for group differentiation.

RESULTS

Good correlations were found between REI and other liver function biomarkers: REI and CPS (rho =  - 0.816; p < 0.001); REI and MELD score (rho =  - 0.755; p < 0.001); REI and ICG-PDR (rho = 0.745; p < 0.001)]. REI correlation was stronger for patients with Child-Pugh A (rho = 0.642, p = 0.002) and B (rho = 0.798, p < 0.001) than for those with Child-Pugh C (rho = 0.336, p = 0.148). REI is significantly lower in patients with poor liver function (p < 0.001). ROC curve showed an AUC 0.94 to discriminate patients with poor liver function (REI cutoff < 100; 100% sensitivity; 76% specificity).

CONCLUSIONS

REI is a valuable non-invasive index for liver function quantification that has good correlations with other liver function biomarkers. REI can be easily calculated and can be used to estimate liver function in clinical practice in the routine evaluation of cirrhotic patients that undergo MR imaging with gadoxetic acid contrast.

KEY POINTS

• REI is a valuable non-invasive index for liver function quantification that has good correlations with other liver function biomarkers. • REI can be easily calculated in the routine evaluation of cirrhotic patients that undergo gadoxetic acid-enhanced MRI. • The REI enables stratification of cirrhotic patients into good and poor liver function groups and can be used as additional information, together with morphological and focal liver lesion evaluation.

Clinical application of preoperative shear wave dispersion for prediction of post liver failure in patients with hepatocellular carcinoma after hepatectomy

OBJECTIVE

The aim in this study was to determine the efficacy of shear wave dispersion (SWD) technique for the prediction of post hepatectomy liver failure (PHLF) in patients with hepatocellular carcinoma after hepatectomy and develop an SWD based risk prediction model.

METHODS & MATERIALS

We prospectively enrolled 205 consecutive patients who were scheduled to undergo hepatectomy for hepatocellular carcinoma (HCC), pre-operative SWD examination, laboratory data and some other clinicopathological tests were collected. The risk factors of PHLF were identified according to univariate and multivariate analysis, a predictive model was established based on logistic regression analyses.

RESULTS

SWD examination was successfully performed in 205 patients. PHLF occurred in 51 patients (24.9%), including 37/11/3 patients with Grade A/B/C, respectively. There was a high correlation between SWD value of liver and liver fibrosis stage (r = 0.873, p < 0.05). Patients with PHLF has a higher median SWD value of liver than patients without PHLF [17.4 vs 14.7 (m/s)/kHz, p < 0.05]. The SWD value of liver, total bilirubin (TB), international normalized ratio of prothrombin time (INR) and splenomegaly were significantly related to PHLF based on the multivariate analysis. A new prediction model (PM) for PHLF was established (PM = -12.918 + 0.183× SWD + 6.668× INR +0.100×TB+1.240×splenomegaly). The optimal cutoff value of SWD for predicting PHLF was 16.7 (m/s)/kHz. The area under the curve (AUC) of the PM for PHLF was 0.833, which was higher than that of SWD, INR, Forns, FIB4, APRI (p < 0.005, respectively).

CONCLUSION

SWD is a promising and reliable method for PHLF prediction in patients with HCC who were undergoing hepatectomy. Compared with SWD, Forns, APRI and FIB-4, PM demonstrate better efficacy for preoperative PHLF prediction.

Clinical value of predictive models based on liver stiffness measurement in predicting liver reserve function of compensated chronic liver disease

BACKGROUND

Assessment of liver reserve function (LRF) is essential for predicting the prognosis of patients with chronic liver disease (CLD) and determines the extent of liver resection in patients with hepatocellular carcinoma.

AIM

To establish noninvasive models for LRF assessment based on liver stiffness measurement (LSM) and to evaluate their clinical performance.

METHODS

A total of 360 patients with compensated CLD were retrospectively analyzed as the training cohort. The new predictive models were established through logistic regression analysis and were validated internally in a prospective cohort (132 patients).

RESULTS

Our study defined indocyanine green retention rate at 15 min (ICGR15) ≥ 10% as mildly impaired LRF and ICGR15 ≥ 20% as severely impaired LRF. We constructed predictive models of LRF, named the mLPaM and sLPaM, which involved only LSM, prothrombin time international normalized ratio to albumin ratio (PTAR), age and model for end-stage liver disease (MELD). The area under the curve of the mLPaM model (0.855, 0.872, respectively) and sLPaM model (0.869, 0.876, respectively) were higher than that of the methods for MELD, albumin-bilirubin grade and PTAR in the two cohorts, and their sensitivity and negative predictive value were the highest among these methods in the training cohort. In addition, the new models showed good sensitivity and accuracy for the diagnosis of LRF impairment in the validation cohort.

CONCLUSION

The new models had a good predictive performance for LRF and could replace the indocyanine green (ICG) clearance test, especially in patients who are unable to undergo ICG testing.

Rational Design of a Near-Infrared Ratiometric Probe with a Large Stokes Shift: Visualization of Polarity Abnormalities in Non-Alcoholic Fatty Liver Model Mice

Tracking liver polarity with noninvasive and dynamic imaging techniques is helpful to better understand the non-alcoholic fatty liver (NAFL). Herein, a novel near-infrared (NIR) fluorescent probe Cy-Mp is constructed using a "symmetry collapse" strategy. The structure modification leads to the conversion of locally excited state fluorescence to charge transfer state fluorescence. Cy-Mp emits at near-infrared (NIR) wavelengths with high photostability as well as a large Stokes shift. Cy-Mp exhibits a ratiometric response to polarity, providing more accurate analysis of intracellular polarity via the built-in internal reference correction. Most importantly, the in vivo studies indicate that Cy-Mp can accumulate in the liver and the decreased polarity in the liver of mice with NAFL is verified by the ratiometric imaging, implying the great potential of Cy-Mp in the diagnosis of NAFL.

Fluorescein clearance kinetics in blood and bile indicates hepatic ischemia-reperfusion injury in rats

Quantitative measurement of the degree of hepatic ischemia-reperfusion injury (IRI) is crucial for developing therapeutic strategies for its treatment. We hypothesized that clearance of fluorescent dye through bile metabolism may reflect the degree of hepatic IRI. In this study, we investigated sodium fluorescein clearance kinetics in blood and bile for quantifying the degree of hepatic IRI. Warm ischemia times (WITs) of 0, 30, or 60 min followed by 1 h or 4 h of reperfusion, were applied to the median and lateral lobes of the liver in Sprague-Dawley rats. Subsequently, 2 mg/kg of sodium fluorescein was injected intravenously, and blood and bile samples were collected over 60 min to measure fluorescence intensities. The bile-to-plasma fluorescence ratios demonstrated an inverse correlation with WIT and were distinctly lower in the 60-min WIT group than in the control or 30-min WIT groups. Bile-to-plasma fluorescence ratios displayed superior discriminability for short versus long WITs when measured 1 h after reperfusion versus 4 h. We conclude that the bile-to-blood ratio of fluorescence after sodium fluorescein injection has the potential to enable the quantification of hepatic IRI severity.NEW & NOTEWORTHY Previous attempts to use fluorophore clearance to test liver function have relied on a single source of data. However, the kinetics of substrate processing via bile metabolism include decreasing levels in blood and increasing levels in bile. Thus, we analyzed data from blood and bile to better reflect fluorescein clearance kinetics.

Assessment of Liver Function With MRI: Where Do We Stand?

Liver disease and hepatocellular carcinoma (HCC) have become a global health burden. For this reason, the determination of liver function plays a central role in the monitoring of patients with chronic liver disease or HCC. Furthermore, assessment of liver function is important, e.g., before surgery to prevent liver failure after hepatectomy or to monitor the course of treatment. Liver function and disease severity are usually assessed clinically based on clinical symptoms, biopsy, and blood parameters. These are rather static tests that reflect the current state of the liver without considering changes in liver function. With the development of liver-specific contrast agents for MRI, noninvasive dynamic determination of liver function based on signal intensity or using T1 relaxometry has become possible. The advantage of this imaging modality is that it provides additional information about the vascular structure, anatomy, and heterogeneous distribution of liver function. In this review, we summarized and discussed the results published in recent years on this technique. Indeed, recent data show that the T1 reduction rate seems to be the most appropriate value for determining liver function by MRI. Furthermore, attention has been paid to the development of automated tools for image analysis in order to uncover the steps necessary to obtain a complete process flow from image segmentation to image registration to image analysis. In conclusion, the published data show that liver function values obtained from contrast-enhanced MRI images correlate significantly with the global liver function parameters, making it possible to obtain both functional and anatomic information with a single modality.

Determination of hepatic clearance by derivations of the indocyanine green retention test in cirrhosis

BACKGROUND AND AIM

The study was undertaken in order to compare single injection indocyanine green (ICG)-clearances with the steady-state ICG-clearance (ICG_Cl ) in patients with cirrhosis in order to assess the most accurate estimate for ICG-clearance and to relate the ICG-clearances to established indicators of liver dysfunction.

METHODS

Thirty-eight patients (male 29) with cirrhosis (Child-Turcotte class A 8, class B 21, and class C 9) were studied during a hemodynamic investigation. A single injection of ICG was followed by blood samples for 5, 10, 15, and 20 min. The dose/plasma area clearance (Cl_A ) and plasma volume · initial slope clearance (Cl_PV ) were determined and compared with the steady-state infusion/plasma concentration ratio clearance (ICG_Cl ).

RESULTS

The Cl_A (310; 214; 502 mL/min) and Cl_PV (294; 164; 481 mL/min) correlated closely with ICG_Cl (243; 120; 383 mL/min [median; interquartile range], R = 0.95-0.98, P < 0.000), but were significantly higher than ICG_Cl (P < 0.001). All three clearance measures correlated significantly with biochemical and hemodynamic variables of liver dysfunction (P < 0.05-0.000). All three ICG-clearances showed significantly lower values in patients with ascites compared to those without, and lower ICG-clearance values were present in patients with esophageal varices compared to those without (P < 0.05-0.002).

CONCLUSION

Single injection markers (Cl_A and Cl_PV ) of the steady-state ICG-clearance as derived from the ICG-retention curve and the plasma volume correlate with ICG_Cl and established variables of portal hypertension and liver cell bile excretory dysfunction. Therefore, these markers can safely replace the more costly ICG_Cl .

A Clinical-Radiomic Model for Predicting Indocyanine Green Retention Rate at 15 Min in Patients With Hepatocellular Carcinoma

Purpose:

The indocyanine green retention rate at 15 min (ICG-R15) is of great importance in the accurate assessment of hepatic functional reserve for safe hepatic resection. To assist clinicians to evaluate hepatic functional reserve in medical institutions that lack expensive equipment, we aimed to explore a novel approach to predict ICG-R15 based on CT images and clinical data in patients with hepatocellular carcinoma (HCC).

Methods

In this retrospective study, 350 eligible patients were enrolled and randomly assigned to the training cohort (245 patients) and test cohort (105 patients). Radiomics features and clinical factors were analyzed to pick out the key variables, and based on which, we developed the random forest regression, extreme gradient boosting regression (XGBR), and artificial neural network models for predicting ICG-R15, respectively. Pearson's correlation coefficient (R) was adopted to evaluate the performance of the models.

Results

We extracted 660 CT image features in total from each patient. Fourteen variables significantly associated with ICG-R15 were picked out for model development. Compared to the other two models, the XGBR achieved the best performance in predicting ICG-R15, with a mean difference of 1.59% (median, 1.53%) and an R-value of 0.90. Delong test result showed no significant difference in the area under the receiver operating characteristic (AUROCs) for predicting post hepatectomy liver failure between actual and estimated ICG-R15.

Conclusion

The proposed approach that incorporates the optimal radiomics features and clinical factors can allow for individualized prediction of ICG-R15 value of patients with HCC, regardless of the specific equipment and detection reagent (NO. ChiCTR2100053042; URL, http://www.chictr.org.cn).

Current and Potential Applications for Indocyanine Green in Liver Transplantation

Indocyanine green (ICG) is a fluorescent dye taken up and almost exclusively cleared by the liver. Measurement of its clearance and visualization of its fluorescence make it suitable for a number of potential applications in liver transplantation including assessment of liver function and real-time assessment of arterial, venous, and biliary structures. ICG clearance can be used to assess donor graft quality before procurement and graft metabolic function before transplant using normothermic ex vivo machine perfusion. ICG clearance in the post-liver transplantation period is able to predict recipient outcomes with correlations to early allograft dysfunction and postoperative complications. After absorbing light in the near-infrared spectrum, ICG also emits fluorescence at 835 nm. This allows the assessment of vascular patency after reconstruction and patterns of liver perfusion in real time. ICG perfusion patterns after revascularization are also associated with posttransplant graft function and survival. ICG fluorescence cholangiography is routine in a number of centers and acts as an aid to identifying the optimal point of bile duct division during living donor liver transplantation to optimize safety for both donor and recipient. In summary, ICG is a versatile tool and has a number of useful applications in the liver transplantation journey including assessment of liver function, perfusion assessment, and cholangiography. Further research and clinical trials are required to validate and standardize its routine use in liver transplantation.

Assessment of hepatic function, perfusion and parenchyma attenuation with indocyanine green, ultrasound and computed tomography in a healthy rat model: Preliminary determination of baseline parameters in a healthy liver

Background

Defining reference intervals in experimental animal models plays a crucial role in pre-clinical studies. The hepatic parameters in healthy animals provide useful information about type and extension of hepatic damage. However, in the majority of the cases, to obtain them require an invasive techniques. Our study combines these determinations with dynamic functional test and imaging techniques to implement a non-invasive protocol for liver evaluation. The aim of the study was to determine reference intervals for hepatic function, perfusion and parenchyma attenuation with analytical and biochemical blood parameters, indocyanine green, ultrasound and computed tomography in six healthy SD rats.

Methods

Six males healthy SD rats were followed for 4 weeks. To determine hepatic function, perfusion and parenchyma attenuation analytical and biochemical blood parameters, indocyanine green, ultrasound and computed tomography were studied. Results were expressed as Means ± standard error of mean (SEM). The significance of differences was calculated by using student t-test, p < 0.05 was considered statistically significant.

Results

Indocyanine green clearance 5 and 10 minutes after its injection was 80.12% and 96.59%, respectively. Approximate rate of decay during the first 5 minutes after injection was 38% per minute. Hepatic perfusion evaluation with the high-frequency ultrasound was related to cardiovascular hemodynamic and renal perfusion. Portal area, hepatic artery resistance index, hepatic artery and portal peak systolic velocity and average between hepatic artery and porta was 3.41 ± 0.62 mm², 0.57 ± 0.04 mm²/s, 693.24±102.53 mm²/s, 150.72 ± 17.80 mm²/s and 4.82 ± 0.96 mm²/s, respectively. Heart rate, cardiac output, left renal artery diammetre and renal blood flow were 331.01 ± 22.22 bpm, 75.58 ± 8.72 mL/min, 0.88 ± 0.04 mm² and 13.65 ± 1.95 mm²/s. CT-scan hepatic average volume for each rat were 21.08±3.32, 17.57±2.76, 14.87±2.83 and 13.67±2.45 cm³ with an average attenuation coefficient of 113.51±18.08, 129,19±7.18, 141,47±1.95 y 151,67±1.2 HU.

Conclusion

Indocyanine green and high-frequency ultrasound could be used in rats as a suitable marker of liver function. Computed tomography, through the study of raw data, help to characterize liver parenchyma, and could be a potential tool for early detection of liver parenchymal alterations and linear follow-up of patients. Further studies in rats with liver disease are necessary to verify the usefulness of these parameters.

Repurposing ICG enables MR/PA imaging signal amplification and iron depletion for iron-overload disorders

Precise and noninvasive theranostic methods to quantify and deplete focal iron are of crucial importance for iron-overload disorders. Here, we developed an indocyanine green (ICG)–based imaging platform to reveal Fe³⁺ in vitro and in vivo. The high sensitivity and specificity of ICG-Fe interaction facilitated MR images with a marked correlation between T₁ signal intensity ratio (T₁SIR) changes and Fe³⁺ concentration in rodent models and humans. On the basis of these findings, a rational design for coordination-driven self-assembly ICG-Lecithin (ICG/Leci) was proposed to determine Fe³⁺. The enhancement of photoacoustic signal at 890 nm with increasing Fe³⁺ concentration showed an over 600% higher linear slope than that of T₁SIR changes in animal models. ICG/Leci also promoted a 100% increase in iron depletion in the liver compared with deferoxamine. The high MR sensitivity and superior photoacoustic contrast, combined with enhanced iron depletion, demonstrate that ICG/Leci is a promising theranostic agent for simultaneous detection and treatment of iron-overload disorders.

Deuterated Indocyanine Green (ICG) with Extended Aqueous Storage Shelf-Life: Chemical and Clinical Implications

Indocyanine Green (ICG) is a clinically approved near-infrared fluorescent dye that is used extensively for various imaging and diagnostic procedures. One drawback with ICG is its instability in water, which means that reconstituted clinical doses have to be used very shortly after preparation. Two deuterated versions of ICG were prepared with deuterium atoms on the heptamethine chain, and the spectral, physiochemical, and photostability properties were quantified. A notable mechanistic finding is that self-aggregation of ICG in water strongly favors dye degradation by a photochemical oxidative dimerization reaction that gives a nonfluorescent product. Storage stability studies showed that replacement of C-H with C-D decreased the dimerization rate constant by a factor of 3.1, and it is likely that many medical and preclinical procedures will benefit from the longer shelf-lives of these two deuterated ICG dyes. The discovery that ICG self-aggregation promotes photoinduced electron transfer can be exploited as a new paradigm for next-generation photodynamic therapies.

Cell therapy for factor V deficiency: An approach based on human decidua mesenchymal stem cells

Deficiency of factor V is a congenital autosomal recessive coagulopathy associated with mutations in the F5 gene that results in mild-to-severe bleeding episodes. Factor V is a component of the prothrombinase complex responsible for accelerating conversion of prothrombin to thrombin. At the present time there are no therapeutic factor V concentrates available. This study was designed to lay the preliminary foundations for future cell-based therapy for patients with severe factor V deficiency. The study showed that hepatospheres, which produce coagulation factors VIII, IX, and V, synthetize and store intracellular glycogen and express albumin levels up to 8 times higher than those of undifferentiated cells. Factor IX and factor V gene expression increased significantly in hepatospheres as compared to undifferentiated cells, whereas factor VIII gene expression remained constant. The factor V protein was detected in the hepatospheres´ secretome. Considering the enormous potential of mesenchymal stem cells as therapeutic agents, this study proposes a highly reproducible method to induce differentiation of mesenchymal stem cells from human placenta to factor V-producing hepatospheres. This strategy constitutes a preliminary step towards a curative treatment of factor V deficiency through advanced therapies such as cell therapy.

Association between the donor to recipient ICG-PDR variation rate and the functional recovery of the graft after orthotopic liver transplantation: A case series

Background

Despite current advances in liver transplant surgery, post-operative early allograft dysfunction still complicates the patient prognosis and graft survival. The transition from the donor has not been yet fully understood, and no study quantifies if and how the liver function changes through its transfer to the recipient. The indocyanine green dye plasma disappearance rate (ICG-PDR) is a simple validated tool of liver function assessment. The variation rate between the donor and recipient ICG-PDR still needs to be investigated.

Materials and methods

Single-center retrospective study. ICG-PDR determinations were performed before graft retrieval (T1) and 24 hours after transplant (T2). The ICG-PDR relative variation rate between T1 and T2 was calculated to assess the graft function and suffering/recovering. Matched data were compared with the MEAF model of graft dysfunction.

Objective

To investigate whether the variation rate between the donor ICG-PDR value and the recipient ICG-PDR measurement on first postoperative day (POD₁) can be associated with the MEAF score.

Results

36 ICG-PDR measurements between 18 donors and 18 graft recipients were performed. The mean donor ICG-PDR was 22.64 (SD 6.35), and the mean receiver’s ICG-PDR on 1st POD was 17.68 (SD 6.60), with a mean MEAF value of 4.51 (SD 1.23). Pearson’s test stressed a good, linear inverse correlation between the ICG-PDR relative variation and the MEAF values, correlation coefficient -0.580 (p = 0.012).

Conclusion

The direct correlation between the donor to recipient ICG-PDR variation rate and MEAF was found. Measurements at T1 and T2 showed an up- or downtrend of the graft performance that reflect the MEAF values.

Assessment of liver injury using indocyanine green fluorescence imaging

Background

To investigate whether indocyanine green (ICG) fluorescence imaging can be used to evaluate chronic and acute liver injury induced by either a high-fat (HF) diet or carbon tetrachloride (CCl₄).

Methods

Sprague-Dawley (SD) rats were randomly divided into three groups: control group, HF diet-induced model group, and CCl₄-induced model group. The chronic and acute liver injury models were induced by a HF diet and intraperitoneal injection of CCl₄, respectively. After HF feeding, the liver index, levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) of the rats were determined. The livers were also collected to evaluate histopathology damage by hematoxylin and eosin (H&E) staining. After in vitro perfusion of the liver and ICG administration, the liver fluorescence intensity and corresponding spectral value were measured by using real-image guided system (REAL-IGS).

Results

After HF feeding, the liver index and levels of serum ALT and AST were significantly increased, and the livers of the rats showed severe histopathological changes. Compared with the control group, the hepatic lobes of the model rats exhibited incomplete green fluorescence, and the corresponding spectral value was markedly reduced.

Conclusions

ICG fluorescence imaging can be used to evaluate liver injury induced by either a HF diet or CCl₄.

Comparison between preoperative two-dimensional shear wave elastography and indocyanine green clearance test for prediction of post-hepatectomy liver failure

Background

Post-hepatectomy liver failure (PHLF) is one of the most serious complications and major causes of liver resection mortality. The purpose of this study is to investigate and compare the performance of preoperative two-dimensional shear wave elastography (2D-SWE) and the indocyanine green (ICG) clearance test for the prediction of PHLF.

Methods

A total of 172 consecutive patients who were undergoing major liver resection were prospectively identified. Patients were evaluated by preoperative 2D-SWE and ICG clearance test. According to the International Study Group of Liver Surgery (ISGLS) recommendations, No PHLF, PHLF A, PHLF B, and PHLF C group classifications were defined. The differences in liver stiffness value (LSV) and ICG retention rate at 15 minutes (ICGR15) among the different PHLF classifications were investigated. The performance of LSV and ICGR15 for diagnosing different classifications of PHLF was compared.

Results

PHLF occurred in 43 (25.0%) patients, and 24 (14.0%) patients were grade A, 14 (8.1%) were grade B, and 5 (2.9%) were grade C. Both LSV and ICGR15 of the PHLF C group were significantly higher than those of the No PHLF group (P=0.025, P=0.001, respectively). According to univariate and multivariate logistic regression analysis, LSV and ICGR15 were significantly related to PHLF (P=0.051, P=0.084, respectively). For diagnosis of ≥ PHLF A, ≥ PHLF B, and ≥ PHLF C, the areas under the receiver operating characteristic curve (AUCs) for 2D-SWE were 0.624 [95% confidence interval (CI): 0.536-0.712, P=0.015], 0.699 (95% CI: 0.576-0.821, P=0.005), and 0.831 (95% CI: 0.737-0.925, P=0.01), respectively. The AUCs of the ICG clearance test were 0.631 (95% CI: 0.542-0.721, P=0.01), 0.570 (95% CI: 0.436-0.704, P=0.32), and 0.717 (95% CI: 0.515-0.920, P=0.098), respectively. The AUC of LSV for the diagnosis of ≥ PHLF A was comparable to that of ICGR15 (P=0.17). The AUCs of LSV were significantly higher than those of ICGR15 for the diagnosis of ≥ PHLF B (P=0.002) and C (P=0.038).

Conclusions

2D-SWE demonstrates the potential to aid in the prediction of the severity of PHLF. Our findings also suggest that the performance of 2D-SWE is better than the ICG clearance test.

Comparison of preoperative two-dimensional shear wave elastography, indocyanine green clearance test and biomarkers for post hepatectomy liver failure prediction in patients with hepatocellular carcinoma

Background

The preoperative prediction of post hepatectomy liver failure (PHLF) is essential, but there is no gold standard for the prediction at present, and the efficacy of different methods for the prediction has not been compared systematically. In this study, we aimed to compare the efficacy of preoperative two-dimensional shear wave elastography (2D-SWE), indocyanine green (ICG) clearance test and biomarkers for PHLF prediction in patients with hepatocellular carcinoma (HCC).

Methods

We retrospectively studied 215 patients with HCC, who had undergone major liver resection in our hospital. Preoperative data of each patient, including liver stiffness value (LSV) of underlying hepatic parenchyma measured by 2D-SWE, ICG retention rate at 15 min (ICG-R15) measured by ICG clearance test, albumin-bilirubin (ALBI) scores, aspartate aminotransferase–platelet ratio index (APRI), and Fibrosis-4 (FIB-4) were collected for analysis. Post hepatectomy outcomes of study patients were also recorded for assessment of PHLF. The study patients were divided into development cohort (133 patients without PHLF, and 17 patients with PHLF) and validation cohort (59 patients without PHLF, and 6 patients with PHLF) randomly.

Results

In the development cohort, LSV, ICG-R15 and ALBI scores were significantly different between patients with and without PHLF, while no significant difference of APRI and FIB-4 scores was found. LSV had higher AUC (the area under the receiver operating characteristic curve) (AUC = 0.795) for PHLF prediction than ICG-R15 (AUC = 0.619) and ALBI scores (AUC = 0.686) (p < 0.05 for all comparisons). In the validation cohort, the cutoff value of LSV obtained from the development cohort, 10.35 kPa,  revealed higher specificity (76.3%) for PHLF prediction than ICG-R15 (specificity: 66.1%) and ALBI scores (specificity: 69.5%) (p < 0.0001).

Conclusions

Compared with ICG-R15, ALBI scores, APRI and FIB-4, LSV measured by 2D-SWE may demonstrate better efficacy for preoperative PHLF prediction in patients with HCC.

Colorectal liver metastases: Current management and future perspectives

The liver is the commonest site of metastatic disease for patients with colorectal cancer, with at least 25% developing colorectal liver metastases (CRLM) during the course of their illness. The management of CRLM has evolved into a complex field requiring input from experienced members of a multi-disciplinary team involving radiology (cross sectional, nuclear medicine and interventional), Oncology, Liver surgery, Colorectal surgery, and Histopathology. Patient management is based on assessment of sophisticated clinical, radiological and biomarker information. Despite incomplete evidence in this very heterogeneous patient group, maximising resection of CRLM using all available techniques remains a key objective and provides the best chance of long-term survival and cure. To this end, liver resection is maximised by the use of downsizing chemotherapy, optimisation of liver remnant by portal vein embolization, associating liver partition and portal vein ligation for staged hepatectomy, and combining resection with ablation, in the context of improvements in the functional assessment of the future remnant liver. Liver resection may safely be carried out laparoscopically or open, and synchronously with, or before, colorectal surgery in selected patients. For unresectable patients, treatment options including systemic chemotherapy, targeted biological agents, intra-arterial infusion or bead delivered chemotherapy, tumour ablation, stereotactic radiotherapy, and selective internal radiotherapy contribute to improve survival and may convert initially unresectable patients to operability. Currently evolving areas include biomarker characterisation of tumours, the development of novel systemic agents targeting specific oncogenic pathways, and the potential re-emergence of radical surgical options such as liver transplantation.

The indocyanine green retention test as a noninvasive marker for esophageal varices in patients with hepatocellular carcinoma

BACKGROUND

The indocyanine green 15-minute retention (ICG-r15) test was considered as a noninvasive marker of esophageal varices (EV) in cirrhotic patients. However, the performance of ICG-r15 in patients with hepatocellular carcinoma (HCC) has rarely been assessed. The aim of this study is to evaluate the value of ICG-r15 as a noninvasive marker of EV in patients with HCC.

METHODS

From October 2007 to December 2018, the study retrospectively enrolled 137 HCC patients with compensated hepatic function who received ICG-r15 tests and endoscopy screening for EV. The predictive value of the ICG-r15 test and other noninvasive markers was also evaluated for the diagnosis of EV, including the aspartate aminotransferase (AST)/alanine aminotransferase ratio, platelet count/spleen diameter ratio, AST/platelet ratio index, Lok index, FIB-4, and Park index.

RESULTS

In the study cohort, 30 (21.9%) patients had EV. The area under the receiver operating characteristic curve for determining EV by ICG-r15 was 0.784 (95% CI: 0.686-0.881, -2 ln (L): 77.889, Akaike information criterion: 79.889), and it had the best predictive value compared with other noninvasive markers. The cutoff value of ICG-r15 to identify EV was 31.0%, and it had 40.0% sensitivity and 98.1% specificity. The cutoff value to exclude EV was 9.5% with 86.7% sensitivity and 50.5% specificity. In the multivariate analysis, ICG-r15 (odds ratio [OR]: 1.062, 1.014-1.114; p = 0.015) and the Park index (OR: 1.535, 1.091-2.159; p = 0.014) were independently related to the presence of EV.

CONCLUSION

ICG-r15 is a practical noninvasive marker with cutoff values of 9.5% for excluding EV and 31.0% for identifying EV in patients with HCC.

Indocyanine green dye clearance test: early graft (dys)-function and long-term mortality after liver transplant. Should we continue to use it? An observational study

Early allograft dysfunction (EAD) can be a serious complication in the immediate postoperative period following liver transplantation. Our aim was to study the prognostic role of the indocyanine green plasma disappearance rate (ICG-PDR) in predicting early and late EAD and mortality at 3 and 12 months and 5 years after liver transplantation. ICG-PDR values were also assessed for association with the Donor Risk Index (DRI). 220 patients underwent orthotopic liver transplantation. In 77 patients, ICG-PDR was assessed on the 1st post-operative (PO) day. ICG, a water-soluble dye almost entirely excreted into the bile, was measured by spectrophotometry to evaluate graft (dys)-function. DRI was calculated in all patients. The primary study outcomes were the presence (or absence) of EAD after transplant and the results of mortality risk factor analysis. EAD occurred in 18 patients. 1st PO day ICG-PDR was significantly associated with EAD (p < 0.005). A threshold ICG-PDR value < 16%/min on the 1st PO day was also associated with patient probability to survive at 3 and 12 months and 5 years. The sensitivity and specificity of the AUC was good in predicting EAD, being 83% and 56%, respectively, for a 1st PO day ICG-PDR cut-off value < 16%/min. In this study, ICG-PDR on the 1st PO day following OLT can reliably predict EAD and survival at 3 and 12 months and 5 years. ICG-PDR should, therefore, be routinely performed on the 1st PO day following OLTx in all patients in light of its important prognostic role.

Tuned near infrared fluorescent hyaluronic acid conjugates for delivery to pancreatic cancer for intraoperative imaging

The prognosis of pancreatic cancer remains poor. Intraoperative fluorescence imaging of tumors could improve staging and surgical resection, thereby improving prognosis. However, imaging pancreatic cancer with macromolecular delivery systems, is often hampered by nonspecific organ accumulation.

Methods: We describe the rational development of hyaluronic acid (HA) conjugates that vary in molecular weight and are conjugated to near infrared fluorescent (NIRF) dyes that have differences in hydrophilicity, serum protein binding affinity, and clearance mechanism. We systematically investigated the roles of each of these properties on tumor accumulation, relative biodistribution, and the impact of intraoperative imaging of orthotopic, syngeneic pancreatic cancer.

Results: Each HA-NIRF conjugate displayed intrapancreatic tumor enhancement. Regardless of HA molecular weight, Cy7.5 conjugation directed biodistribution to the liver, spleen, and bowels. Conjugation of IRDye800 to 5 and 20 kDa HA resulted in low liver and spleen signal while enhancing the tumor up to 14-fold compared to healthy pancreas, while 100 kDa HA conjugated to IRDye800 resulting in liver and spleen accumulation.

Conclusion: These studies demonstrate that by tuning HA molecular weight and the physicochemical properties of the conjugated moiety, in this case a NIRF probe, peritoneal biodistribution can be substantially altered to achieve optimized delivery to tumors intraoperative abdominal imaging.

Cerebral cortex and respiratory muscles perfusion during spontaneous breathing attempts in ventilated patients and its relation to weaning outcomes: a protocol for a prospective observational study

INTRODUCTION

In addition to the well-documented factors that contribute to weaning failure, increased energy demands of the respiratory muscles during spontaneous breathing trials (SBTs) might not be met by sufficient increases in energy supplies. This discrepancy may deprive blood and oxygen of other tissues. In this context, restrictions in perfusion of splanchnic organs and non-working muscles during SBT have been associated with weaning failure. However, alterations in perfusion of the brain during the weaning process are less well understood.

OBJECTIVE AND HYPOTHESIS

To investigate whether cerebral cortex perfusion evolves differentially during the transition from mechanical ventilation (MV) to spontaneous breathing between patients failing or succeeding the SBT. We hypothesise that patients failing the SBT will exhibit reduced cerebral cortex perfusion during the transition from MV to spontaneous breathing as compared with patients succeeding the SBT.

METHODS AND ANALYSIS

This single-centre, prospective, observational study will be conducted in a medical Intensive Care unit of University Hospital Leuven, Belgium in ready to wean patients. Blood flow index in the cerebral cortex (prefrontal area), inspiratory (scalene) and expiratory muscle (upper rectus abdominis) and a non-working muscle (thenar eminence) will be simultaneously assessed by near-infrared spectroscopy (NIRS) using the tracer indocyanine green dye. Measurements will be performed on the same day during MV and during SBT. NIRS-derived tissue oxygenation index and cardiac output (by pulse contour analyses) will be recorded continuously. Twenty patients failing an SBT are estimated to be sufficient for detecting a significant difference in the change of cerebral cortex perfusion from MV to SBT (primary outcome) between SBT failure and success patients.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the local ethical committee (Ethische Commissie Onderzoek UZ/KU Leuven protocol ID: S60516). Results from this study will be presented at scientific meetings and congresses and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03240263; Pre-results.

Effects of glepaglutide, a novel long-acting glucagon-like peptide-2 analogue, on markers of liver status in patients with short bowel syndrome: findings from a randomised phase 2 trial

Background

With the introduction of glucagon-like peptide-2 (GLP-2) in the treatment of short bowel syndrome (SBS), there is emerging evidence that GLP-2 may play a role in the restoration of the disturbed homeostatic feedback in the gut-liver axis and may ameliorate SBS-associated liver damage.

We have previously presented that daily subcutaneous injections with 1 and 10 mg of glepaglutide improved intestinal function in patients with SBS. As exploratory endpoints, we here assessed the effect of glepaglutide on liver function.

Methods

Liver tests, transient elastography (TE) with controlled attenuation parameter (CAP), indocyanine green (ICG) kinetics, soluble CD163 (sCD163), soluble mannose receptor (sMR), and lipopolysaccharide binding protein (LBP) were assessed in 18 patients with SBS in a randomised, cross-over, dose-finding phase 2 trial before and after three weeks of treatment with glepaglutide. This trial is completed and registered at ClinicalTrials.gov: NCT02690025.

Findings

Between Feb 2016 and Jan 2017, 22 patients with SBS were screened. Of these, 18 patients were randomised and treated with glepaglutide; 16 patients completed the trial. Treatment with glepaglutide was associated with increase in TE and ICG-elimination. In the 10 mg dose group, glepaglutide increased sCD163 by 0·44 mg/mL (P = 0·0498), and alkaline phosphatase (ALP) decreased in the 1 mg dose group by 33 U/L (P = 0·032). CAP, sMR, LBP, liver transaminases, and INR were not affected.

Interpretation

Glepaglutide may improve hepatic excretory function, but at the same time activate resident liver macrophages and increase liver stiffness. The excretory and the stiffness findings may to some extent relate to increased splanchnic blood flow which would not influence the marker of macrophage activation. Thus, glepaglutide exerted diverse effects on liver status that call for attention in future studies.

Funding

Zealand Pharma.

Indocyanine green retention test in cirrhosis and portal hypertension: Accuracy and relation to severity of disease

BACKGROUND AND AIMS

Patients with cirrhosis and portal hypertension often develop complications relating to hepatic excretory dysfunction. The standard measurement of the hepatic excretion is the constant infusion indocyanine green clearance (ICG_CI ) technique. The ICG 15-min retention test (ICG-r15) is faster, more patient friendly, and cheaper. The aims were to compare the ICG-r15 test with the standard method, to assess relations to patient characteristics and survival, and to assess the ICG-r15 level in healthy control subjects.

METHODS

This study included 68 patients with cirrhosis and portal hypertension (Child class A/B/C:17/37/14). All patients underwent a full liver vein catheterization and hemodynamic evaluation with determination of ICG-r15 and ICG_CI as the reference in a subset of 38 patients. Sixteen healthy control subjects were included for compiling a reference interval.

RESULTS

The ICG-r15 was increased in the cirrhotic patients with increasing values in parallel with liver dysfunction (15/41/58%) in Child class A/B/C compared with 7% in the controls (P < 0.001). ICG-r15 correlated highly significantly with the ICG_CI (r = -0.96, P < 0.0001) and in a multivariate regression analysis with hepatic venous pressure gradient, markers of liver dysfunction and hyperdynamic circulation (P < 0.05-0.005). In the control group, normal reference values ranged from 0% to 13%. In addition, ICG-r15 was significantly related to mortality in the patient group (P = 0.02).

CONCLUSIONS

Indocyanine green-r15 reflects portal hypertension, the degree of hepatic failure, and survival and may replace the standard ICG_CI . A more elaborated reference interval needs to be compiled, and the prognostic value of ICG-r15 should be validated.

Minimally invasive assessment of hepatic function in children with indocyanine green elimination: a validation study

Objectives: Pediatric liver disease (PLD) covers a variety of etiologies and severities, from mild temporary illness to diseases with fatal outcomes. There is a demand for minimally invasive and reliable measures for assessment of the severity of PLD. Indocyanine green (ICG) elimination kinetics to estimate hepatic function has been used in adults for decades, however, due to invasiveness, the use in PLD is still limited. The aim of the present study was to evaluate minimally invasive estimation of ICG elimination by pulse spectrophotometry (ICGLi), in comparison with traditional spectrophotometry using serial blood samples (ICGbs). Methods: One hundred children aged 0-18 years were included in the study. ICG elimination kinetics was measured with ICGLi and ICGbs, and results compared by failure rates, mean difference, limits of agreement, Bland Altman plots and linear regression analysis. Plasma disappearance rates (PDRLi and PDRbs) were used for comparison. Results: One hundred and twelve simultaneous measurements in 87 patients were performed successfully. Mean difference for PDR (%/min) was 3.58 (95% CI 2.69; 4.47). Limits of agreement were -5.06; 12.22. A linear correlation between the two methods with a regression coefficient of 0.83 (SE 0.02 95% CI 0.80; 0.87) was found. For conversion we computed the following equation; PDRbs = 0.83 × PDRLi. Conclusions: The present study shows that ICG PDR can be obtained by a minimally invasive method and thus replace measures by serial blood samples in children with liver disease of different etiologies and severities. However, a systematic relative difference between the two methods exists. Our proposed correction factor needs to be validated in larger cohorts.

Non-invasive Evaluation of NAFLD with Indocyanine Green Clearance Test: a Preliminary Study in Morbidly Obese Patients Undergoing Bariatric Surgery

BACKGROUND

Overweight and obesity dramatically increased in the last years. Hepatic complication of obesity, integrated in the term of non-alcoholic fatty liver disease (NAFLD), is a spectrum of abnormality ranging from steatosis to non-alcoholic steatohepatitis (NASH), potentially leading to cirrhosis. Liver biopsy remains the gold standard to evaluate the stage of NAFLD; however, the procedure is invasive. The indocyanine green (ICG) clearance test is performed since years to assess hepatic function before partial hepatectomy, or after liver transplantation. This study was designed to detect liver complications with the ICG clearance test in a population of obese patients scheduled for bariatric surgery.

METHODS

In a prospective cohort study, morbidly obese individuals receiving bariatric surgery with scheduled hepatic biopsies were investigated. Liver function was determined by the ICG test preoperatively, and blood samples were collected. Liver biopsy specimens were obtained for each patient and classified according to the NAFLD activity score (NAS) by a single pathologist that was blinded to the results of the ICG test.

RESULTS

Twenty-six patients were included (7 male and 19 female). The mean age of participants was 45.8 years; the mean body mass index was 41.4 kg/m². According to the NAS, 6 (23.1%) patients revealed manifest NASH, and 5 patients were considered borderline (19.2%). A closed correlation was observed between the ICG clearance test and hepatic steatosis (r = 0.43, p = 0.03), NAS (r = 0.44, p = 0.025), and fibrosis (r = 0.49, p = 0.01).

CONCLUSIONS

In obese patients, non-invasive evaluation of liver function with the indocyanine green clearance test correlated with histological features of NAFLD. This may detect non-invasively hepatopathy in obese population and could motive biopsy.

Radiation-Induced Liver Disease and Modern Radiotherapy

Modern radiotherapy techniques have enabled high focal doses of radiation to be delivered to patients with primary and secondary malignancies of the liver. The current clinical practice of radiation oncology has benefitted from decades of research that have informed how to achieve excellent local control and survival outcomes with minimal toxicities. Still, one of the most devastating consequences of radiation to the liver remains a challenge: radiation-induced liver disease (RILD). Here, we will review the current understanding of classic and nonclassic RILD from a clinical perspective, the evaluation and management of patients who are at risk of developing RILD, methods to reduce the likelihood of RILD using modern radiation techniques, and the diagnosis and treatment of radiation-related liver toxicities.

Near-infrared fluorescence laparoscopy of the ureter with three preclinical dyes in a pig model

Background

Ureteric injury is reported to occur in 1–7.6% of colorectal surgeries. To reduce the incidence of ureteral injury, it is essential to identify the ureters. The use of near-infrared fluorescence (NIRF) imaging with intravenously administered dyes might be of added value for ureteral visualization during laparoscopy. The aim of this study is to assess the performance of three preclinical dyes; IRDye^® 800BK, IRDye^® 800NOS and IRDye^® 800CW, for near-infrared fluorescence laparoscopy of the ureter in pigs.

Methods

In three female Dutch landrace pigs, the new dyes were evaluated. In each pig, 1 dye was tested using a 6-mg intravenous dose in a concentration of 1 mg/ml. Imaging was performed in fluorescence mode and white light mode with a laparoscopic imaging system. In order to further evaluate the dyes, an ex vivo imaging experiment was performed, in which 8 decreasing concentrations per dye, diluted in PBS, were evaluated in a transparent test tube with NIRF mode at a distance of 1, 5 and 10 cm from the laparoscope.

Results

All three dyes were effective in allowing the identification of the ureter with NIRF imaging. The ureter became fluorescent after 35, 45 and 10 min, respectively, for IRDye^® 800BK, IRDye^® 800NOS and IRDye^® 800CW with a maximum target-to-background ratio (TBR) of 2.14, 0.66 and 1.44, respectively. In the ex vivo imaging experiment, all three dyes produced a strong fluorescence signal at all concentrations and all distances evaluated.

Conclusions

Intravenous administration of the preclinical dyes IRDye^® 800CW, IRDye^® 800 BK and IRDye^® 800NOS facilitated successful identification of the anatomical course of the ureter in living pig models. The highest measured TBR occurred with the use of IRDye^® 800BK. Ex vivo, a correlation was observed between the fluorescence intensities of the signal with the concentration of the dye and with the distance to the object.

Indocyanine green-based fluorescence imaging in visceral and hepatobiliary and pancreatic surgery: State of the art and future directions

In recent years, the use of fluorescence-guided surgery (FGS) to treat benign and malignant visceral, hepatobiliary and pancreatic neoplasms has significantly increased. FGS relies on the fluorescence signal emitted by injected substances (fluorophores) after being illuminated by ad hoc laser sources to help guide the surgical procedure and provide the surgeon with real-time visualization of the fluorescent structures of interest that would be otherwise invisible. This review surveys and discusses the most common and emerging clinical applications of indocyanine green (ICG)-based fluorescence in visceral, hepatobiliary and pancreatic surgery. The analysis, findings, and discussion presented here rely on the authors' significant experience with this technique in their medical institutions, an up-to-date review of the most relevant articles published on this topic between 2014 and 2018, and lengthy discussions with key opinion leaders in the field during recent conferences and congresses. For each application, the benefits and limitations of this technique, as well as applicable future directions, are described. The imaging of fluorescence emitted by ICG is a simple, fast, relatively inexpensive, and harmless tool with numerous different applications in surgery for both neoplasms and benign pathologies of the visceral and hepatobiliary systems. The ever-increasing availability of visual systems that can utilize this tool will transform some of these applications into the standard of care in the near future. Further studies are needed to evaluate the strengths and weaknesses of each application of ICG-based fluorescence imaging in abdominal surgery.

Redox-responsive polymeric micelles formed by conjugating gambogic acid with bioreducible poly(amido amine)s for the co-delivery of docetaxel and MMP-9 shRNA

A novel redox-sensitive system for co-delivering hydrophobic drugs and hydrophilic siRNA or shRNA was developed by conjugating gambogic acid (GA) with poly(amido amine)s (PAAs) through amide bonds, which is called GA-conjugated PAAs (PAG). PAG can self-assemble into micelles as amphiphilic block copolymers, which exhibits an excellent loading ability for the co-delivery of docetaxel (DTX) and MMP-9 shRNA with adjustable dosing ratios. In addition, confocal microscopy, flow cytometry and in vitro transfection analyses demonstrated more efficient cellular internalization of DTX and MMP-9 shRNA after incubation with PAG/DTX- MMP-9 shRNA micelles (PAG/DTX-shRNA) than with free drugs. Unlike traditional amphiphilic copolymer micelles, GA conjugated in PAG possesses an intrinsic anticancer efficacy. The presence of disulfide bonds in PAAs enables rapid disassembly of PAG micelles in response to reducing agents, inducing the release of loaded drugs (DTX, GA and MMP-9 shRNA). In vitro cellular assays revealed that PAG/DTX-shRNA micelles inhibited MCF-7 cell proliferation more efficiently than the single drug or single drug-loaded micelles. In vivo biodistribution and anti-tumor effect studies using an MCF-7 breast cancer xenograft mouse model have indicated that PAG/DTX-shRNA micelles can enhance drug accumulation compared with the free drug, thereby sustaining the therapeutic effect on tumors. Additionally, PAG/DTX-shRNA micelles displayed a greater anti-tumor efficacy than Taxotere® and PAG-shRNA micelles. These results suggest that the redox-sensitive PAG platform is a promising co-delivery system for combining drugs and gene therapy for the treatment of cancer.

STATEMENT OF SIGNIFICANCE

The PAG micelles were designed by conjugating gambogic acid (GA) with poly(amido amine)s (PAAs), which would serve dual purposes as both gene and drugs co-delivery carrier and an anti-tumor prodrug. Unlike traditional amphiphilic micelles, GA conjugated in PAG could exert its intrinsic efficacy and provide synergistic antiproliferative effects with docetaxel (DTX) on MCF-7 cells. Disulfide bonds in PAG enables a rapid disassembly of PAG micelles in response to reducing agents and to release all loaded drugs (DTX, GA and MMP-9 shRNA) at tumor sites. PAG/DTX-shRNA micelles displayed greater anti-tumor efficacy than that of Taxotere®, indicating the design concept for PAG works well. And the strategy for PAG could be used to develop a series of similar co-delivery systems through conjugations of other small-molecule drugs with PAAs, such as doxorubicin, methotrexate and other drugs with carboxy groups in their structure.

Could Ultrasound Elastography Reflect Liver Function?

The purpose of this study was to investigate whether ultrasound elastography reflects liver function reserve relative to liver fibrosis histology. Sixty-five New Zealand rabbits were divided into an experimental group (n = 45) and a control group (n = 20). In the experimental group, liver fibrosis (F1-F4) was induced by subcutaneous injection of carbon tetrachloride. Point shear wave elastography and the indocyanine green (ICG) elimination test were performed for the two groups at 4-wk intervals for 56 wk. The liver stiffness value (LSV) and the ICG retention rate at 15 min (ICGR15) were obtained, and the correlation between them was investigated. The median LSVs of stages F0-F4 were 3.92 kPa (1.91-8.53 kPa), 5.02 kPa (2.39-8.91 kPa), 7.87 kPa (5.21-12.26 kPa), 12.83 kPa (5.92-16.79 kPa) and 16.64 kPa (9.76-29.50 kPa), respectively. The median ICGR15 values of stages F0-F4 were 8.7% (4.8%-15.6%), 10.8% (5.6%-20.3%), 19.2% (12.3%-26.7%), 31.0% (20.9%-41.0%) and 45.6% (22.1%-60.9%). There were significant differences in LSVs and ICGR15 values among the different stages of liver fibrosis (p <0.01). A positive correlation was observed between LSV and ICGR15 (r = 0.7497, p < 0.0001). A strong correlation was observed between liver stiffness and liver function reserve, indicating ultrasound elastography may reflect liver function reserve in different degrees of liver fibrosis.

Photonic monitoring of treatment during infection and sepsis: development of new detection strategies and potential clinical applications

Despite the strong decline in the infection-associated mortality since the development of the first antibiotics, infectious diseases are still a major cause of death in the world. With the rising number of antibiotic-resistant pathogens, the incidence of deaths caused by infections may increase strongly in the future. Survival rates in sepsis, which occurs when body response to infections becomes uncontrolled, are still very poor if an adequate therapy is not initiated immediately. Therefore, approaches to monitor the treatment efficacy are crucially needed to adapt therapeutic strategies according to the patient's response. An increasing number of photonic technologies are being considered for diagnostic purpose and monitoring of therapeutic response; however many of these strategies have not been introduced into clinical routine, yet. Here, we review photonic strategies to monitor response to treatment in patients with infectious disease, sepsis, and septic shock. We also include some selected approaches for the development of new drugs in animal models as well as new monitoring strategies which might be applicable to evaluate treatment response in humans in the future. Figure Label-free probing of blood properties using photonics.

Development of a simple indocyanine green measurement method using an automated biochemical analyser

Background The indocyanine green retention rate is important for assessing the severity of liver disorders. In the conventional method, blood needs to be collected twice. In the present study, we developed an automated indocyanine green method that does not require blood sampling before intravenous indocyanine green injections and is applicable to an automated biochemical analyser. Methods The serum samples of 471 patients collected before and after intravenous indocyanine green injections and submitted to the clinical laboratory of our hospital were used as samples. The standard procedure established by the Japan Society of Hepatology was used as the standard method. In the automated indocyanine green method, serum collected after an intravenous indocyanine green injection was mixed with the saline reagent containing a surfactant, and the indocyanine green concentration was measured at a dominant wavelength of 805 nm and a complementary wavelength of 884 nm. Results The coefficient of variations of the within- and between-run reproducibilities of this method were 2% or lower, and dilution linearity passing the origin was noted up to 10 mg/L indocyanine green. The reagent was stable for four weeks or longer. Haemoglobin, bilirubin and chyle had no impact on the results obtained. The correlation coefficient between the standard method (x) and this method (y) was r=0.995; however, slight divergence was noted in turbid samples. Conclusion Divergence in turbid samples may have corresponded to false negativity with the standard procedure. Our method may be highly practical because blood sampling before indocyanine green loading is unnecessary and measurements are simple.

Photoacoustic-Guided Surgery with Indocyanine Green-Coated Superparamagnetic Iron Oxide Nanoparticle Clusters

A common cause of local tumor recurrence in brain tumor surgery results from incomplete surgical resection. Adjunctive technologies meant to facilitate gross total resection have had limited efficacy to date. Contrast agents used to delineate tumors preoperatively cannot be easily or accurately used in the real-time operative setting. Although multimodal imaging contrast agents are developed to help the surgeon discern tumor from normal tissue in the operating room, these contrast agents are not readily translatable. This study has developed a novel contrast agent comprised solely of two Food and Drug Administration approved components, indocyanine green (ICG) and superparamagnetic iron oxide (SPIO) nanoparticles-with no additional amphiphiles or carrier materials, to enable preoperative detection by magnetic resonance (MR) imaging and intraoperative photoacoustic (PA) imaging. The encapsulation efficiency of both ICG and SPIO within the formulated clusters is ≈100%, and the total ICG payload is 20-30% of the total weight (ICG + SPIO). The ICG-SPIO clusters are stable in physiologic conditions; can be taken up within tumors by enhanced permeability and retention; and are detectable by MR. In a preclinical surgical resection model in mice, following injection of ICG-SPIO clusters, animals undergoing PA-guided surgery demonstrate increased progression-free survival compared to animals undergoing microscopic surgery.

Using Indocyanine Green Extraction to Predict Liver Function After Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma

PURPOSE

To test the hypothesis that mid-treatment measures of the retention of indocyanine green after 15 minutes (ICGR15) would improve the prediction of posttreatment liver function in the setting of hepatocellular carcinoma.

METHODS AND MATERIALS

Between 2006 and 2015, 144 patients with hepatocellular carcinoma received 175 courses of stereotactic body radiation therapy (SBRT). Patient data, such as age, sex, portal vein thrombosis, cirrhosis, Child-Pugh (CP) score, prior liver-directed therapies, and liver function tests, including albumin-bilirubin (ALBI) and ICG clearance, and dosimetric data, such as tumor volume and radiation dose, were collected. Toxicity was evaluated as a 2-point increase in CP score or a change in ALBI score at 3 months from start of SBRT. Logistic or linear regression was used to build toxicity prediction models based on patient and tumor characteristics and ICG clearance variables. Performance of the models for the binary CP outcome was summarized using area under the curve and receive operating characteristic curves. Likelihood ratio tests were used to evaluate whether the model fit improved after incorporating the ICG variable information.

RESULTS

In multivariable analysis age, baseline ICGR15, and change in ICGR15 were associated with toxicity defined by increased CP score. For the continuous ALBI outcome, being female, having cirrhosis, and increasing radiation dose were associated with increased toxicity. When incorporating ICGR15 into these models, an increase in ICGR15 from baseline to mid-treatment was most consistently significantly associated with an increase in toxicity.

CONCLUSIONS

Incorporation of ICGR15 variables significantly improves the prediction of post-SBRT liver function. The use of ICGR15 can facilitate the delivery of the maximum safe dose of radiation for patients with hepatocellular carcinoma and has the potential to improve uncomplicated tumor control and survival.

Dynamic and accurate assessment of acetaminophen-induced hepatotoxicity by integrated photoacoustic imaging and mechanistic biomarkers in vivo

The prediction and understanding of acetaminophen (APAP)-induced liver injury (APAP-ILI) and the response to therapeutic interventions is complex. This is due in part to sensitivity and specificity limitations of currently used assessment techniques. Here we sought to determine the utility of integrating translational non-invasive photoacoustic imaging of liver function with mechanistic circulating biomarkers of hepatotoxicity with histological assessment to facilitate the more accurate and precise characterization of APAP-ILI and the efficacy of therapeutic intervention. Perturbation of liver function and cellular viability was assessed in C57BL/6J male mice by Indocyanine green (ICG) clearance (Multispectral Optoacoustic Tomography (MSOT)) and by measurement of mechanistic (miR-122, HMGB1) and established (ALT, bilirubin) circulating biomarkers in response to the acetaminophen and its treatment with acetylcysteine (NAC) in vivo. We utilised a 60% partial hepatectomy model as a situation of defined hepatic functional mass loss to compared acetaminophen-induced changes to. Integration of these mechanistic markers correlated with histological features of APAP hepatotoxicity in a time-dependent manner. They accurately reflected the onset and recovery from hepatotoxicity compared to traditional biomarkers and also reported the efficacy of NAC with high sensitivity. ICG clearance kinetics correlated with histological scores for acute liver damage for APAP (i.e. 3h timepoint; r=0.90, P<0.0001) and elevations in both of the mechanistic biomarkers, miR-122 (e.g. 6h timepoint; r=0.70, P=0.005) and HMGB1 (e.g. 6h timepoint; r=0.56, P=0.04). For the first time we report the utility of this non-invasive longitudinal imaging approach to provide direct visualisation of the liver function coupled with mechanistic biomarkers, in the same animal, allowing the investigation of the toxicological and pharmacological aspects of APAP-ILI and hepatic regeneration.

The Application of Heptamethine Cyanine Dye DZ-1 and Indocyanine Green for Imaging and Targeting in Xenograft Models of Hepatocellular Carcinoma

Near infrared fluorescence (NIRF) imaging has strong potential for widespread use in noninvasive tumor imaging. Indocyanine green (ICG) is the only Food and Drug Administration (FDA) -approved NIRF dye for clinical diagnosis; however, it is unstable and poorly targets tumors. DZ-1 is a novel heptamethine cyanine NIRF dye, suitable for imaging and tumor targeting. Here, we compared the fluorescence intensity and metabolism of DZ-1 and ICG. Additionally, we assayed their specificities and abilities to target tumor cells, using cultured hepatocellular carcinoma (HCC) cell lines, a nude mouse subcutaneous xenograft model of liver cancer, and a rabbit orthotopic transplantation model. We found that DZ-1 accumulates in tumor tissue and specifically recognizes HCC in subcutaneous and orthotopic models. The NIRF intensity of DZ-1 was one order of magnitude stronger than that of ICG, and DZ-1 showed excellent intraoperative tumor targeting in the rabbit model. Importantly, ICG accumulated at tumor sites, as well as in the liver and kidney. Furthermore, DZ-1 analog-gemcitabine conjugate (NIRG) exhibited similar tumor-specific targeting and imaging properties, including inhibition of tumor growth, in HCC patient-derived xenograft (PDX) mice. DZ-1 and NIRG demonstrated superior tumor-targeting specificity, compared to ICG. We show that DZ-1 is an effective molecular probe for specific imaging, targeting, and therapy in HCC.

In vivo visualization and ex vivo quantification of experimental myocardial infarction by indocyanine green fluorescence imaging

The fluorophore indocyanine green accumulates in areas of ischemia-reperfusion injury due to an increase in vascular permeability and extravasation of the dye. The aim of the study was to validate an indocyanine green-based technique of in vivo visualization of myocardial infarction. A further aim was to quantify infarct size ex vivo and compare this technique with the standard triphenyltetrazolium chloride staining. Wistar rats were subjected to regional myocardial ischemia (30 minutes) followed by reperfusion (n = 7). Indocyanine green (0.25 mg/mL in 1 mL of normal saline) was infused intravenously for 10 minutes starting from the 25th minute of ischemia. Video registration in the near-infrared fluorescence was performed. Epicardial fluorescence of indocyanine green corresponded to the injured area after 30 minutes of reperfusion. Infarct size was similar when determined ex vivo using traditional triphenyltetrazolium chloride assay and indocyanine green fluorescent labeling. Intravital visualization of irreversible injury can be done directly by fluorescence on the surface of the heart. This technique may also be an alternative for ex vivo measurements of infarct size.