Relation of biliary bile acid output to hepatic adenosine triphosphate level and biliary indocyanine green excretion in humans

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).

Histological and toxicological evaluation, in rat, of a P-glycoprotein inducer and activator: 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5)

P-glycoprotein (P-gp) is an ATP-binding cassette transporter involved in the efflux of numerous compounds that influences the pharmacokinetics of xenobiotics. It reduces intestinal absorption and exposure of target cells to toxicity. Thioxanthones are compounds able to induce and/or activate P-gp in vitro. Particularly, 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) behaves as a P-gp inducer and activator in vitro. The aims of this study were: i) to perform a histological characterization, by testing a single high dose of TX5 [30 mg/kg, body weight (b.w.), gavage], administered to Wistar Han rats, 24 hours after administration; and ii) to perform both a complete histological characterization and a preliminary safety evaluation, in distinct target organs, 24 hours after administration of a single lower dose of TX5 (10 mg/kg, b.w., gavage) to Wistar Han rats. The results showed a relevant histological toxicity for the higher dose of TX5 administered (30 mg/kg, b.w.), manifested by extensive hepatic necrosis and splenic toxicity (parenchyma with hyperemia, increased volume of both white and red pulp, increased follicles marginal zone). Moreover, in the kidneys, a slight hyperemia and tubular edema were observed in TX5-treated animals, as well as an inflammation of the small intestine. On the contrary, for the lower tested dose (10 mg/kg, b.w.), we did not observe any relevant histological toxicity in the evaluated organs. Additionally, no significant differences were found in the ATP levels between TX5-exposed and control animals in any of the evaluated organs, with the exception of the intestine, where ATP levels were significantly higher in TX5-treated rats. Similarly, TX5 caused a significant increase in the ratio GSH/GSSG only in the lungs. TX5 (10 mg/kg, b.w.) did not induce any change in any of the hematological and biochemical circulating evaluated parameters. However, TX5 was able to significantly reduce the activated partial thromboplastin time, without affecting the prothrombin time. The urine biochemical analysis revealed a TX5-mediated increase in both creatinine and sodium. Taken together, our results show that TX5, at a dose of 10 mg/kg, does not induce considerable toxicity in the biological matrices studied. Given this adequate safety profile, TX5 becomes a particularly interesting compound for ex vivo and in vivo studies, regarding the potential for induction and activation of P-gp at the intestinal barrier.

Bile Modulates Secretion of Incretins and Insulin: A Study of Human Extrahepatic Cholestasis

OBJECTIVE

Changes in bile flow after bariatric surgery may beneficially modulate secretion of insulin and incretins, leading to diabetes remission. However, the exact mechanism(s) involved is still unclear. Here, we propose an alternative method to investigate the relationship between alterations in physiological bile flow and insulin and incretin secretion by studying changes in gut-pancreatic function in extrahepatic cholestasis in nondiabetic humans.

METHODS

To pursue this aim, 58 nondiabetic patients with recent diagnosis of periampullary tumors underwent an oral glucose tolerance test (OGTT), and a subgroup of 16 patients also underwent 4-hour mixed meal tests and hyperinsulinemic-euglycemic clamps.

RESULTS

The analysis of the entire cohort revealed a strong inverse correlation between total bilirubin levels and insulinogenic index. When subjects were divided on the basis of bilirubin levels, used as a marker of altered bile flow, subjects with high bilirubin levels displayed inferior glucose control and decreased insulin secretion during the OGTT. Altered bile flow elicited a markedly greater increase in glucagon and glucagon-like peptide 1 (GLP-1) secretion at fasting state, and following the meal, both glucagon and GLP-1 levels remained increased over time. Conversely, Glucose-dependent insulinotropic polypeptide (GIP) levels were comparable at the fasting state, whereas the increase following meal ingestion was significantly blunted with high bilirubin levels. We reveal strong correlations between total bilirubin and glucagon and GLP-1 levels.

CONCLUSIONS

Our findings suggest that acute extrahepatic cholestasis determines major impairment in enteroendocrine gut-pancreatic secretory function. The altered bile flow may determine a direct deleterious effect on β-cell function, perhaps mediated by the impairment of incretin hormone function.

Predictive Value of Indocyanine Green Plasma Disappearance Rate on Liver Function and Complications After Liver Transplantation

BACKGROUND The aim of this study was to investigate the correlation between indocyanine green plasma disappearance rate (ICG-PDR) and allograft function as well as postoperative complications after liver transplantation. MATERIAL AND METHODS In this prospective study, 115 cases of adult liver transplantation performed from 1 June 2016 to 1 December 2016 were enrolled. These 115 patients were divided into a group of PDR <18%/min (50 cases) and a group of PDR ≥18%/min (65 cases). The rates of liver recovery, postoperative complications, and survival were compared between these 2 groups. RESULTS Among the total of 115 patients, 111 patients recovered well and were discharged, whereas 4 patients died during the first month after the operation. Between the 2 groups, significant differences were observed in terms of the model for end-stage liver disease (MELD) score, intraoperative bleeding volume, and the level of hemoglobin (Hb), pre-albumin (PA) and total bilirubin (TB) the first week after the operation. Overall, the incidence of hepatic arterial complications and pneumonia was much higher in the PDR<18%/min group (P<0.05). CONCLUSIONS The early postoperative value of ICG-PDR was closely related to graft function and could act as a good predictor for the incidence of postoperative arterial complications.

Species differences in bile acids II. Bile acid metabolism

One of the mechanisms of drug-induced liver injury (DILI) involves alterations in bile acid (BA) homeostasis and elimination, which encompass several metabolic pathways including hydroxylation, amidation, sulfation, glucuronidation and glutathione conjugation. Species differences in BA metabolism may play a major role in the failure of currently used in vitro and in vivo models to predict reliably the DILI during the early stages of drug discovery and development. We developed an in vitro cofactor-fortified liver S9 fraction model to compare the metabolic profiles of the four major BAs (cholic acid, chenodeoxycholic acid, lithocholic acid and ursodeoxycholic acid) between humans and several animal species. High- and low-resolution liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance imaging were used for the qualitative and quantitative analysis of BAs and their metabolites. Major species differences were found in the metabolism of BAs. Sulfation into 3-O-sulfates was a major pathway in human and chimpanzee (4.8%-52%) and it was a minor pathway in all other species (0.02%-14%). Amidation was primarily with glycine (62%-95%) in minipig and rabbit and it was primarily with taurine (43%-81%) in human, chimpanzee, dog, hamster, rat and mice. Hydroxylation was highest (13%-80%) in rat and mice followed by hamster, while it was lowest (1.6%-22%) in human, chimpanzee and minipig. C6-β hydroxylation was predominant (65%-95%) in rat and mice, while it was at C6-α position in minipig (36%-97%). Glucuronidation was highest in dog (10%-56%), while it was a minor pathway in all other species (<12%). The relative contribution of the various pathways involved in BA metabolism in vitro were in agreement with the observed plasma and urinary BA profiles in vivo and were able to predict and quantify the species differences in BA metabolism. In general, overall, BA metabolism in chimpanzee is most similar to human, while BA metabolism in rats and mice is most dissimilar from human.

Melatonin role preventing steatohepatitis and improving liver transplantation results

Liver steatosis is a prevalent process that is induced due to alcoholic or non-alcoholic intake. During the course of these diseases, the generation of reactive oxygen species, followed by molecular damage to lipids, protein and DMA occurs generating organ cell death. Transplantation is the last-resort treatment for the end stage of both acute and chronic hepatic diseases, but its success depends on ability to control ischemia-reperfusion injury, preservation fluids used, and graft quality. Melatonin is a powerful endogenous antioxidant produced by the pineal gland and a variety of other because of its efficacy in organs; melatonin has been investigated to improve the outcome of organ transplantation by reducing ischemia-reperfusion injury and due to its synergic effect with organ preservation fluids. Moreover, this indolamine also prevent liver steatosis. That is important because this disease may evolve leading to an organ transplantation. This review summarizes the observations related to melatonin beneficial actions in organ transplantation and ischemic-reperfusion models.

Assessment of Liver Remnant Using ICG Clearance Intraoperatively during Vascular Exclusion: Early Experience with the ALIIVE Technique

Background. The most significant risk following major hepatectomy is postoperative liver insufficiency. Current preoperative assessment of the future liver remnant relies upon assumptions which may not be valid in the setting of advanced resection strategies. This paper reports the feasibility of the ALIIVE technique which assesses the liver remnant with ICG clearance intraoperatively during vascular exclusion. Methods. 10 patients undergoing planned major liver resection (hemihepatectomy or greater) were recruited. Routine preoperative assessment included CT and standardized volumetry. ICG clearance was measured noninvasively using a finger spectrophotometer at various time points including following parenchymal transection during inflow and outflow occlusion before vascular division, the ALIIVE step. Results. There were one case of mortality and three cases of posthepatectomy liver failure. The patient who died had the lowest ALIIVE ICG clearance (7.1%/min versus 14.4 ± 4.9). Routine preoperative CT and standardized volumetry did not predict outcome. Discussion/Conclusion. The novel ALIIVE technique is feasible and assesses actual future liver remnant function before the point of no return during major hepatectomy. This technique may be useful as a check step to offer a margin of safety to prevent posthepatectomy liver failure and death. Further confirmatory studies are required to determine a safety cutoff level.

Alterations in hepatic lobar function in regenerating rat liver

BACKGROUND

Ligation of a branch of the portal vein redirects portal blood to nonligated lobes resulting in lobar hypertrophy. Although the effect of portal vein ligation on liver volume is well documented, the parallel alterations in liver function are still the subject of controversy. Our aim was to assess the time-dependent reactions of regional hepatic function to portal vein ligation by selective biliary drainage.

METHODS

Male Wistar rats (n = 44) underwent 80% portal vein ligation. Before the operation as well as 1, 2, 3, 5, and 7 d after circulation, morphology and function (laboratory blood test; hepatic bile flow; plasma disappearance rate of indocyanine green; and biliary indocyanine green excretion) of the liver were examined.

RESULTS

Although portal vein ligation affected liver circulation and morphology to a great extent, serum albumin levels, bilirubin levels, and total hepatic bile flow did not change significantly after the operation. Nevertheless, plasma disappearance rate and biliary indocyanine green excretion indicated a temporary impairment of total liver function with the lowest value on the second day and normalization by the fifth day. Bile production and biliary indocyanine green excretion of ligated lobes decreased rapidly after the operation and remained persistently suppressed, whereas the secretory function of nonligated lobes--after a temporary decline--showed a greater increase than the weight of the lobes.

CONCLUSIONS

Portal vein ligation induced temporary impairment of total liver function, followed by rapid recovery mainly by reason of increase in the function of nonligated lobes. Functional increase in nonligated lobes was more pronounced than suggested by the degree of volume gain.

[Indocyanine green elimination for the evaluation of liver function: prognostic value in patients with community-acquired sepsis]

BACKGROUND

The aim of our clinical study was to correlate liver function measured by indocyanine green (ICG) elimination and clinical outcomes in patients with an early stage of community-acquired sepsis (CAS).

MATERIALS AND METHODS

A total of 341 patients (≥ 18 years) presenting with suspicion of CAS or evidence of an infection and fulfillment of ≥ 2 systemic inflammatory response syndrome (SIRS) criteria were included in the observational study"Prognosis of early sepsis 2" (Prognose der frühen Sepsis 2, ProFS 2). Patients who had been hospitalized within the last 7 days were excluded. In a subgroup of these patients (n = 72) who were transferred to an intensive or intermediate care unit according to the clinical judgment of the treating physicians, ICG elimination (plasma disappearance rate, ICG-PDR; 15 min retention rate, ICG-R15) was assessed by using a noninvasive monitoring system (LiMON, PULSION Medical Systems, Germany). ICG-PDR and -R15 were determined on the day of admission (n = 72) and after 96 h (n = 34). The primary end point of the study was defined as death within 30 days. Secondary endpoints were need for renal replacement therapy, requirement for invasive mechanical ventilation, and length of stay in an intermediate or intensive care unit.

RESULTS AND CONCLUSION

In contrast to patients with sepsis or severe sepsis, ICG elimination was found to be significantly impaired in patients with septic shock. Furthermore, a significant predictive value of ICG-PDR and -R15 on the day of admission for the need for subsequent renal replacement therapy (n = 12) was observed. In addition, reduced ICG elimination was associated with a longer stay in an intermediate or intensive care unit. However, ICG elimination on admission could not predict 30-day mortality (n = 14) or requirement of mechanical ventilation (n = 20).

Human drug-induced liver injury severity is highly associated with dual inhibition of liver mitochondrial function and bile salt export pump

Drug-induced liver injury (DILI) accounts for 20-40% of all instances of clinical hepatic failure and is a common reason for withdrawal of an approved drug or discontinuation of a potentially new drug from clinical/nonclinical development. Numerous individual risk factors contribute to the susceptibility to human DILI and its severity that are either compound- and/or patient-specific. Compound-specific primary mechanisms linked to DILI include: cytotoxicity, reactive metabolite formation, inhibition of bile salt export pump (BSEP), and mitochondrial dysfunction. Since BSEP is an energy-dependent protein responsible for the efflux of bile acids from hepatocytes, it was hypothesized that humans exposed to drugs that impair both mitochondrial energetics and BSEP functional activity are more sensitive to more severe manifestations of DILI than drugs that only have a single liability factor. As annotated in the United States National Center for Toxicological Research Liver Toxicity Knowledge Base (NCTR-LTKB), the inhibitory properties of 24 Most-DILI-, 28 Less-DILI-, and 20 No-DILI-concern drugs were investigated. Drug potency for inhibiting BSEP or mitochondrial activity was generally correlated across human DILI concern categories. However, drugs with dual potency as mitochondrial and BSEP inhibitors were highly associated with more severe human DILI, more restrictive product safety labeling related to liver injury, and appear more sensitive to the drug exposure (Cmax) where more restrictive labeling occurs.

CONCLUSION

These data affirm that severe manifestations of human DILI are multifactorial, highly associated with combinations of drug potency specifically related to known mechanisms of DILI (like mitochondrial and BSEP inhibition), and, along with patient-specific factors, lead to differences in the severity and exposure thresholds associated with clinical DILI.

Profiling circulating and urinary bile acids in patients with biliary obstruction before and after biliary stenting

Bile acids are considered as extremely toxic at the high concentrations reached during bile duct obstruction, but each acid displays variable cytotoxic properties. This study investigates how biliary obstruction and restoration of bile flow interferes with urinary and circulating levels of 17 common bile acids. Bile acids (conjugated and unconjugated) were quantified by liquid chromatography coupled with tandem mass spectrometry in serum and urine samples from 17 patients (8 men and 9 women) with biliary obstruction, before and after biliary stenting. Results were compared with serum concentrations measured in 40 age- and sex-paired control donors (20 men and 20 women). The total circulating bile acid concentration increases from 2.7 µM in control donors to 156.9 µM in untreated patients with biliary stenosis. Serum taurocholic and glycocholic acids exhibit 304- and 241-fold accumulations in patients with biliary obstruction compared to controls. The enrichment in chenodeoxycholic acid species reached a maximum of only 39-fold, while all secondary and 6α-hydroxylated species--except taurolithocholic acids--were either unchanged or significantly reduced. Stenting was efficient in restoring an almost normal circulating profile and in reducing urinary bile acids.

CONCLUSION

These results demonstrate that biliary obstruction affects differentially the circulating and/or urinary levels of the various bile acids. The observation that the most drastically affected acids correspond to the less toxic species supports the activation of self-protecting mechanisms aimed at limiting the inherent toxicity of bile acids in face of biliary obstruction.

Molecular adsorbent recirculating system in patients with early allograft dysfunction after liver transplantation: a pilot study

Early allograft dysfunction (EAD) after orthotopic liver transplantation (OLT) causes marked morbidity and mortality. We conducted a prospective pilot study to assess the safety and efficacy of molecular adsorbent recirculating system (MARS) in treatment of EAD after OLT. Twelve consecutive adult liver allograft recipients with a median age of 48 years, 9 of whom were male, were prospectively included and supported with MARS. EAD was defined as the presence of at least 2 of the following: serum bilirubin >10 mg/dL, prothrombin time <40%, aspartate aminotransferase or alanine transferase >1,000 U/L, and plasma disappearance rate of indocyanine green (PDR(ICG)) <10% per minute within 72 hours after reperfusion. One-year patient and graft survival was 66%. There was a significant decrease in serum bilirubin (P = 0.002), serum creatinine (P = 0.006), and aspartate aminotransferase (P = 0.005) and a significant increase in PDR(ICG) (P = 0.007) after MARS treatment. Prothrombin time, albumin level, and platelet count remained stable. Sustained improvement of renal and neurological function and of mean arterial pressure were observed. No MARS-related adverse effects occurred. MARS treatment provides a safe approach to the treatment of EAD after OLT. On the basis of this pilot study, a multicenter randomized clinical trial that uses MARS treatment in EAD after OLT has been initiated.

Plasma disappearance of indocyanine green: a marker for excretory liver function?

OBJECTIVE

To investigate whether the plasma disappearance rate of indocyanine green (ICG) assessed using a commercially available bedside monitor provides an accurate estimation of cumulative biliary ICG excretion in a clinically relevant model of long-term, hyperdynamic porcine endotoxemia.

DESIGN AND SETTING

Prospective experimental study in the animal laboratory in a university hospital.

SUBJECTS

Fifteen domestic pigs.

INTERVENTIONS

Pigs were anesthetized, mechanically ventilated, and instrumented. Intravenous endotoxin was continuously infused over 12 h concomitant with fluid resuscitation. Measurements were performed before and 12 h after the start of endotoxin infusion.

MEASUREMENTS AND RESULTS

All animals developed hyperdynamic circulation characterized by a sustained increase in cardiac output. Despite well maintained portal venous and consequently total liver blood flow endotoxemia decreased hepatic lactate uptake, which was accompanied by a significant fall in portal and hepatic venous pH. Both the cumulative bile flow and biliary ICG and bicarbonate excretion measured during 1 h after intravenous bolus of 25 mg ICG fell significantly. By contrast, neither the plasma disappearance rate of ICG nor the rate corrected for liver blood flow exhibited any changes over time.

CONCLUSIONS

In hyperdynamic porcine endotoxemia the plasma disappearance rate of ICG failed to accurately substitute for direct short-term measures of biliary ICG excretion. Hence normal values of plasma disappearance rate of ICG should be interpreted with caution in early, acute inflammatory conditions.

Exogenous melatonin enhances bile flow and ATP levels after cold storage and reperfusion in rat liver: implications for liver transplantation

Although the use of melatonin in the transplantation field has been suggested, it has not been previously tested in a liver cold-storage model. We used a rat liver model to study (a) the dose-dependent effect of melatonin on bile production, and (b) the potential of melatonin to improve liver function after cold-storage. Male Wistar rats were perfused with Krebs-Henseleit bicarbonate buffer (KHB) at 37 degrees C without or with 25, 50, 100 and 200 microM melatonin. Each dose of melatonin stimulated bile production. For cold-storage studies, livers were flushed with either University of Wisconsin (UW) or Celsior solution and stored for 20 hr at 4 degrees C. Reperfusion (120 min) was performed with KHB at 37 degrees C. In subsequent studies, 100 microM melatonin were added to the perfusate during the reperfusion period. ATP and melatonin levels in the tissue were measured. Bile analysis was performed by measuring melatonin, bilirubin and gamma-glutamyl transpeptidase (gamma-GT) levels in the fluid. A dose-dependent increase in bile secretion, associated with an enhanced melatonin and bilirubin levels in the bile were observed. Also, tissue levels of melatonin increased in a dose-dependent manner. When melatonin was added during the reperfusion period, bile production and bile bilirubin levels increased both with UW and Celsior solutions. The analysis of gamma-GT in the bile showed an increase in the Celsior-preserved liver and the addition of melatonin to the perfusate reduced this effect. Tissue ATP levels were higher when melatonin was added to the perfusion medium. Higher levels of melatonin in bile than in tissue were found. In conclusion, we demonstrate that melatonin improves significantly the restoration of liver function after cold-storage and reperfusion.

Comparison of invasive and noninvasive measurement of plasma disappearance rate of indocyanine green in patients undergoing liver transplantation: a prospective investigator-blinded study

Plasma disappearance rate of indocyanine green (PDRICG) has been proposed for assessment of liver function in liver transplants donors and recipients, in patients with chronic liver failure, and as a prognostic factor in critically ill patients. The assessment of PDRICG using a newly developed noninvasive digital pulse densitometry method was simultaneously compared to invasive aortic fiber-optic method in patients undergoing orthotopic liver transplantation (OLT). Fourteen consecutive liver transplant candidates (11 male, 3 female) were prospectively enrolled into the study. A 4F aortic catheter with an integrated fiber-optic device and a thermistor was inserted via a femoral artery sheath for invasive aortic (INV) PDRICG assessment in all patients. The fiber-optic device was connected to a computer system (COLD-Z021, PULSION Medical Systems, Munich, Germany). A finger-piece sensor was used for non-invasive (NINV) pulse-densitometric PDRICG assessment. For the PDRICG assessment.5 mg/kg of ICG in cooled saline (10-15 mL) was injected through a central venous catheter. The assessments of PDRICG were performed after induction of anesthesia, after clamping of the hepatic artery, after clamping of the inferior vena cava, after reperfusion of the graft, and on the first postoperative day. During the PDRICG measurements, the investigators were blinded for the results of the noninvasive monitoring. Seventy-one pairs of measurements were performed successfully. PDRICG ranged from 0%/min to 43.8 %/min (11.6%/min +/- 9.6 %/min, mean +/- SD) for invasive and from 2.6%/min to 36.1 %/min (10%/min +/- 7.6 %/min, mean +/- SD) for noninvasive assessment method. The linear regression analysis yielded the equation: PDRICG(NINV) = 1.493 +/- 0.735 x PDRICG(INV), with a correlation coefficient of r = 0.93 (P <.0001). The analysis according to Bland and Altman showed a good agreement between the PDRICG(NINV) and PDRICG(INV) with a mean bias 1.5 +/- 3.8 for all measurements. In conclusion, according to these results, the noninvasive transcutaneous pulse-densitometric method correlates well with the invasive aortic fiber-optic method and thus can be used in patients undergoing liver transplantation.