In-situ evaluation the fluctuation of hypochlorous acid in acute liver injury mice models with a mitochondria-targeted NIR ratiometric fluorescent probe.

Acute liver injury (ALI) is a frequent and devastating liver disease that has been made more prevalent by the excessive use of chemicals, drugs, and alcohol in modern life. Hypochlorous acid (HClO), an important biomarker of oxidative stress originating mainly from the mitochondria, has been shown to be intimately connected to the development and course of ALI. Herein, a novel BODIPY-based NIR ratiometric fluorescent probe Mito-BS was constructed for the specific recognition of mitochondrial HClO. The probe Mito-BS can rapidly respond to HClO within 20 s with a ratiometric fluorescence response (from 680 nm to 645 nm), 24-fold fluorescence intensity ratio enhancement (I645/I680), a wide pH adaptation range (5-9) and the low detection limit (31 nM). The probe Mito-BS has been effectively applied to visualize endogenous and exogenous HClO fluctuations in living zebrafish and cells based on its low cytotoxicity and prominent mitochondria-targeting ability. Furthermore, the fluorescent probe Mito-BS makes it possible to achieve the non-invasive in-situ diagnosis of ALI through in mice, and provides a feasible strategy for early diagnosis and drug therapy of ALI and its complications.

Label-Free Screening of Drug-Induced Liver Injury Using Stimulated Raman Scattering Microscopy and Spectral Phasor Analysis.

Hepatic toxicity is a leading cause of the termination of clinical trials and the withdrawal of therapeutics following regulatory approval. The detection of drug-induced liver injury (DILI) is therefore of importance to ensure patient safety and the effectiveness of novel small molecules and drugs. DILI encompasses drug-induced steatosis (DIS) and drug-induced phospholipidosis (DIPL) which involve the accumulation of excess intracellular lipids. Here, we develop hyperspectral stimulated Raman scattering (SRS) microscopy as a label-free methodology for discriminating DIS and DIPL in mammalian cell culture. We demonstrate that hyperspectral SRS imaging in tandem with spectral phasor analysis is capable of discriminating DIS and DIPL based on the nature and distribution of intracellular lipids resulting from each process. To demonstrate the practical application of this methodology, we develop a panel of alkyne-tagged propranolol analogues that display varying DILI effects. Using hyperspectral SRS imaging together with spectral phasor analysis, our label-free methodology corroborated the standard fluorescence-based assay for DILI. As a label-free screening method, it offers a convenient and expedient methodology for visualizing hepatotoxicity in cell cultures which could be integrated into the early stages of the drug development process for screening new chemical entities for DILI.

Biothiols-activated near-infrared frequency up-conversion luminescence probe for early evaluation of drug-induced hepatotoxicity.

A novel biothiols-sensitive near-infrared (NIR) fluorescent probe RhDN based on a rhodamine skeleton was developed for early detection of drug-induced hepatotoxicity in living mice. RhDN can be used not only as a conventional large stokes shift fluorescent (FL) probe, but also as a kind of anti-Stokes frequency upconversion luminescence (FUCL) molecular probe, which represents a long wavelength excitation (808 nm) to short wavelength emission (760 nm), and response to Cys/Hcy/GSH with high sensitivity. Compared with traditional FL methods, the FUCL method exhibited a lower detection limit of Cys, Hcy, and GSH in 75.1 nM, 101.8 nM, and 84.9 nM, respectively. We exemplify RhDN for tracking endogenously biothiols distribution in living cells and further realize real-time in vivo bioimaging of biothiols activity in mice with dual-mode luminescence system. Moreover, RhDN has been successfully applied to visualize the detection of drug-induced hepatotoxicity in living mice. Overall, this report presents a unique approach to the development of large stokes shift NIR FUCL molecular probes for in vitro and in vivo biothiols biosensing.

Peroxynitrite imaging in ferroptosis-mediated drug-induced liver injury with a near-infrared fluorescence probe.

BACKGROUND: Over-consumption of drugs can result in drug-induced liver damage (DILI), which can worsen liver failure. Numerous studies have shown the significant role ferroptosis plays in the pathophysiology of DILI, which is typified by a marked imbalance between the generation and breakdown of lipid reactive oxygen species (ROS). The content of peroxynitrite (ONOO-) rapidly increased during this process and was thought to be a significant marker of early liver injury. Therefore, the construction of fluorescence probe for the detection and imaging of ONOO- holds immense importance in the early diagnosis and treatment of ferroptosis-mediated DILI. RESULTS: We designed a probe DILI-ONOO based on the ICT mechanism for the purpose of measuring and visualizing ONOO- in ferroptosis-mediated DILI processes and associated studies. This probe exhibited significant fluorescence changes with good sensitivity, selectivity, and can image exogenous and endogenous ONOO- in cells with low cytotoxicity. Using this probe, we were able to show changes in ONOO- content in ferroptosis-mediated DILI cells and mice models induced by the intervention of acetaminophen (APAP) and isoniazid (INH). By measuring the concentration of ferroptosis-related indicators in mice liver tissue, we were able to validate the role of ferroptosis in DILI. It is worth mentioning that compared to existing alanine transaminase (ALT) and aspartate aminotransferase (AST) detection methods, this probe can achieve early identification of DILI prior to serious liver injury. SIGNIFICANCE: This work has significant reference value in researching the relationship between ferroptosis and DILI and visualizing research. The results indicate a strong correlation between the progression of DILI and ferroptosis. Additionally, the use of DILI-ONOO shows promise in investigating the DILI process and assessing the effectiveness of medications in treating DILI.

Visualization of Endogenous Hypochlorite in Drug-Induced Liver Injury Mice via a Bioluminescent Probe Combined with Firefly Luciferase mRNA-Loaded Lipid Nanoparticles.

Drug-induced liver injury (DILI) is a common liver disease with a high rate of morbidity, and its pathogenesis is closely associated with the overproduction of highly reactive hypochlorite (ClO-) in the liver. However, bioluminescence imaging of endogenous hypochlorite in nontransgenic natural mice remains challenging. Herein, to address this issue, we report a strategy for imaging ClO- in living cells and DILI mice by harnessing a bioluminescent probe formylhydrazine luciferin (ClO-Luc) combined with firefly luciferase (fLuc) mRNA-loaded lipid nanoparticles (LNPs). LNPs could efficiently deliver fLuc mRNA into living cells and in vivo, expressing abundant luciferase in the cytoplasm in situ. In the presence of ClO-, probe ClO-Luc locked by formylhydrazine could release cage-free d-luciferin through oxidation and follow-up hydrolysis reactions, further allowing for bioluminescence imaging. Moreover, based on the luciferase-luciferin system, it was able to sensitively and selectively detect ClO- in vitro with a limit of detection of 0.59 µM and successfully monitor the endogenous hypochlorite generation in the DILI mouse model for the first time. We postulate that this work provides a new method to elucidate the roles of ClO- in related diseases via bioluminescence imaging.

Ultrasensitive upconverting nanoprobes for in situ imaging of drug-induced liver injury using miR-122 as the biomarker.

Drug-induced liver injury (DILI) is a frequent adverse drug reaction. The current clinical diagnostic methods are inadequate for accurate and early detection of DILI due to the lack of effective diagnostic biomarkers. Hepatocyte-specific miR-122 is released from injured hepatocytes promptly and its efflux is significantly correlated with the progression of DILI. Therefore, achieving precise in situ detection of miR-122 with high sensitivity is vital for early visualization of DILI. Herein, a new nanoprobe, consisting of miR-122 aptamer, upconversion nanoparticles (UCNPs) and Prussian blue nanoparticles (PBNPs) was introduced for the early and sensitive detection of DILI in situ. As the nanoprobes reached in the liver, miR-122 aptamer-based entropy-driven strand displacement (ESDR) signal amplification reaction was triggered and luminescence resonance energy transfer (LRET) between UCNPs and PBNPs was responded to achieve the high-fidelity detection of DILI. A negative correlation was observed between the intensity of upconversion luminescence (UCL) and the concentration of miR-122. UCL imaging conducted both in vivo and ex vivo indicated that a reduction in miR-122 concentration led to an increase in UCL intensity, revealing a precise state of DILI. The detection technique demonstrated a positive correlation between signal intensity and severity, offering a more straightforward and intuitive method of visualizing DILI.

Application of multiple-finding segmentation utilizing Mask R-CNN-based deep learning in a rat model of drug-induced liver injury.

Drug-induced liver injury (DILI) presents significant diagnostic challenges, and recently artificial intelligence-based deep learning technology has been used to predict various hepatic findings. In this study, we trained a set of Mask R-CNN-based deep algorithms to learn and quantify typical toxicant induced-histopathological lesions, portal area, and connective tissue in Sprague Dawley rats. We compared a set of single-finding models (SFMs) and a combined multiple-finding model (MFM) for their ability to simultaneously detect, classify, and quantify multiple hepatic findings on rat liver slide images. All of the SFMs yielded mean average precision (mAP) values above 85%, suggesting that the models had been successfully established. The MFM showed better performance than the SFMs, with a total mAP value of 92.46%. We compared the model predictions for slide images with ground-truth annotations generated by an accredited pathologist. For the MFM, the overall and individual finding predictions were highly correlated with the annotated areas, with R-squared values of 0.852, 0.952, 0.999, 0.990, and 0.958 being obtained for portal area, infiltration, necrosis, vacuolation, and connective tissue (including fibrosis), respectively. Our results indicate that the proposed MFM could be a useful tool for detecting and predicting multiple hepatic findings in basic non-clinical study settings.

Non-Solvatochromic Cell Membrane-Targeted NIR Fluorescent Probe for Visualization of Polarity Abnormality in Drug-Induced Liver Injury Mice.

Noninvasive visualization of liver polarity by using fluorescence imaging technology is helpful to better understand drug-induced liver injury (DILI). However, cell membrane-targeted polarity-sensitive near-infrared (NIR) fluorescent probes are still scarce. Herein, we report a non-solvatochromic cell membrane-targeted NIR small molecular probe (N-BPM-C10) for monitoring the polarity changes on cell membranes in living cells and in vivo. N-BPM-C10 exhibits polarity-dependent fluorescence around 655 nm without an obvious solvatochromic effect, which endows it with good capability for the in vivo imaging study. Moreover, it can rapidly and selectively light up the cell membranes as well as distinguish tumor cells from normal cells due to its excellent polarity-sensitive ability. More importantly, N-BPM-C10 has been successfully applied to visualize liver polarity changes in vivo, revealing the reduction of liver polarity in DILI mice. We believe that N-BPM-C10 provides a new way for the diagnosis of DILI.

Screening and optimization of a water-soluble near-infrared fluorescent probe for drug-induced liver injury monitoring.

Peroxynitrite (ONOO-) is a potential biomarker of drug-induced liver injury (DILI) and is involved in the process of DILI. Therefore, developing a reliable detection method for ONOO- will greatly contribute to ensuring drug safety and improving treatment efficiency. Here, based on the previous work, two kinds of NIR fluorescence probes PN and SPN were developed with phenyl-hydrazine as the ONOO- recognition group, which based on two fluorophores RN and SRN that are stable to ONOO-. A sensitive NIR probe SPN with good water solubility, low detection limit and good biocompatibility was selected through in vitro spectral property screening. Further experimental results show that there is a good linear relationship between the response intensity of probe SPN to ONOO- and the concentration of ONOO-, and the detection limit can reach 19.7 nM. At the cellular level, probe SPN can achieve a good and specific response to endogenous and exogenous ONOO-. Also, the probe SPN can be used for imaging and detection of DILI in zebrafish level and small animal level, indicating that probe SPN can be used as a powerful tool for diagnosis of DILI and efficacy evaluation of therapeutic drugs.

Label-Free Imaging Techniques to Evaluate Metabolic Changes Caused by Toxic Liver Injury in PCLS.

Abuse with hepatotoxic agents is a major cause of acute liver failure. The search for new criteria indicating the acute or chronic pathological processes is still a challenging issue that requires the selection of effective tools and research models. Multiphoton microscopy with second harmonic generation (SHG) and fluorescence lifetime imaging microscopy (FLIM) are modern label-free methods of optical biomedical imaging for assessing the metabolic state of hepatocytes, therefore reflecting the functional state of the liver tissue. The aim of this work was to identify characteristic changes in the metabolic state of hepatocytes in precision-cut liver slices (PCLSs) under toxic damage by some of the most common toxins: ethanol, carbon tetrachloride (CCl4) and acetaminophen (APAP), commonly known as paracetamol. We have determined characteristic optical criteria for toxic liver damage, and these turn out to be specific for each toxic agent, reflecting the underlying pathological mechanisms of toxicity. The results obtained are consistent with standard methods of molecular and morphological analysis. Thus, our approach, based on optical biomedical imaging, is effective for intravital monitoring of the state of liver tissue in the case of toxic damage or even in cases of acute liver injury.

Clinic-radiomics model using liver magnetic resonance imaging helps predict chronicity of drug-induced liver injury.

BACKGROUND AND AIMS: Some drug-induced liver injury (DILI) cases may become chronic, even after drug withdrawal. Radiomics can predict liver disease progression. We established and validated a predictive model incorporating the clinical characteristics and radiomics features for predicting chronic DILI. METHODS: One hundred sixty-eight DILI patients who underwent liver gadolinium-diethylenetriamine pentaacetate-enhanced magnetic resonance imaging were recruited. The patients were clinically diagnosed using the Roussel Uclaf causality assessment method. Patients who progressed to chronicity or recovery were randomly divided into the training (70%) and validation (30%) cohorts, respectively. Hepatic T1-weighted images were segmented to extract 1672 radiomics features. Least absolute shrinkage and selection operator regression was used for feature selection, and Rad-score was constructed using support vector machines. Multivariable logistic regression analysis was performed to build a clinic-radiomics model incorporating clinical characteristics and Rad-scores. The clinic-radiomics model was evaluated for its discrimination, calibration, and clinical usefulness in the independent validation set. RESULTS: Of 1672 radiomics features, 28 were selected to develop the Rad-score. Cholestatic/mixed patterns and Rad-score were independent risk factors of chronic DILI. The clinic-radiomics model, including the Rad-score and injury patterns, distinguished chronic from recovered DILI patients in the training (area under the receiver operating characteristic curve [AUROC]: 0.89, 95% confidence interval [95% CI]: 0.87-0.92) and validation (AUROC: 0.88, 95% CI: 0.83-0.91) cohorts with good calibration and great clinical utility. CONCLUSION: The clinic-radiomics model yielded sufficient accuracy for predicting chronic DILI, providing a practical and non-invasive tool for managing DILI patients.

A Highly Sensitive and Selective Near-Infrared Fluorescent Probe for Imaging Peroxynitrite in Living Cells and Drug-Induced Liver Injury Mice.

Drug-induced liver injury (DILI) is a major clinical issue associated with the majority of commercial drugs. During DILI, the peroxynitrite (ONOO-) level is upregulated in the liver. However, traditional methods are unable to timely monitor the dynamic changes of the ONOO- level during DILI in vivo. Therefore, ONOO--activated near-infrared (NIR) fluorescent probes with high sensitivity and selectivity are key to the early diagnosis of DILI in situ. Herein, we report a novel ONOO--responsive NIR fluorescent probe, QCy7-DP, which incorporates a donor-dual-acceptor π-electron cyanine skeleton with diphenyl phosphinate. The ONOO--mediated highly selective hydrolytic cleavage via an addition-elimination pathway of diphenyl phosphinate produced the deprotonated form of QCy7 in physiological conditions with a distinctive extended conjugated π-electron system and ∼200-fold enhancement in NIR fluorescence emission at 710 nm. Moreover, the probe QCy7-DP was successfully used for the imaging of the endogenous and exogenous ONOO- concentration changes in living cells. Importantly, in vivo fluorescence imaging tests demonstrated that the probe can effectively detect the endogenous generation of ONOO- in an acetaminophen (APAP)-induced liver injury mouse model. This study provides insight into the design of highly selective NIR fluorescent probes suitable for spatiotemporal monitoring of ONOO- under different pathological conditions.

Rational design of a NIR fluorescent probe for carboxylesterase 1 detection during endoplasmic reticulum stress and drug-induced acute liver injury.

An endoplasmic reticulum targeting NIR fluorescent probe (ERBM) was developed for real-time monitoring of carboxylesterase 1 (CES1) and exhibited excellent ER location in living cell imaging. In addition, ERBM was applied to illustrate the regulation characteristics of CES1 under ER stress and acute liver injury models at the cell and animal level.

Mathematical models for biomarker calculation of drug-induced liver injury in humans and experimental models based on gadoxetate enhanced magnetic resonance imaging.

BACKGROUND: Drug induced liver injury (DILI) is a major concern when developing new drugs. A promising biomarker for DILI is the hepatic uptake rate of the contrast agent gadoxetate. This rate can be estimated using a novel approach combining magnetic resonance imaging and mathematical modeling. However, previous work has used different mathematical models to describe liver function in humans or rats, and no comparative study has assessed which model is most optimal to use, or focused on possible translatability between the two species. AIMS: Our aim was therefore to do a comparison and assessment of models for DILI biomarker assessment, and to develop a conceptual basis for a translational framework between the species. METHODS AND RESULTS: We first established which of the available pharmacokinetic models to use by identifying the most simple and identifiable model that can describe data from both human and rats. We then developed an extension of this model for how to estimate the effects of a hepatotoxic drug in rats. Finally, we illustrated how such a framework could be useful for drug dosage selection, and how it potentially can be applied in personalized treatments designed to avoid DILI. CONCLUSION: Our analysis provides clear guidelines of which mathematical model to use for model-based assessment of biomarkers for liver function, and it also suggests a hypothetical path to a translational framework for DILI.

Identification of MRI features associated with injury type, severity, and prognosis in drug-induced liver injury.

OBJECTIVES: To identify magnetic resonance imaging (MRI) features associated with injury type, severity, and liver transplantation (LT)/liver-related death (LRD) in drug-induced liver injury (DILI). METHODS: The eligible DILI patients (2016 to 2020) who underwent contrast abdominal MRI within 3 months of onset were retrospectively analysed at Beijing Friendship Hospital, Capital Medical University. The MRI features independently associated with severity and prognosis were identified by backwards logistic regression. Unadjusted odds ratios (ORs) and 95% confidence intervals (CIs) are given. RESULTS: The median age of 180 patients was 55.5 years, with 126 (70.0%) women. The injury types included hepatocellular (135 cases, 75.0%), mixed (23, 12.8%), and cholestatic (22, 12.2%). The proportion of periportal oedema in patients with hepatocellular and mixed injury was significantly higher than that in cholestatic injury (62.2%, 47.8% vs. 18.2%, p < 0.001). For severity, 157 (87.2%) patients had mild to moderate injury, and 23 (12.8%) had severe to fatal/LT. Irregularity of the liver surface (6.56 (95% CI, 1.27-22.84)), transient hepatic attenuation difference (THAD) (3.27 (95% CI, 1.14-9.36)), and splenomegaly (5.86 (95% CI, 1.96-17.53)) were independently associated with severity. Eight (4.4%) patients died/underwent LT. THAD (8.89 (95% CI, 1.35-58.43)), and ascites (64.63 (95% CI, 6.93-602.40)) were independently associated with LT/LRD. The prediction of the new model employing THAD and ascites for LT/LRD within 1 year was 0.959 (95% CI, 0.917-1.000). CONCLUSIONS: Periportal oedema was associated with the type of injury. Irregularity of the liver surface, THAD, and splenomegaly were associated with severity. THAD and ascites may have potential clinical utility in predicting LT/LRD outcomes within 1 year. KEY POINTS: • Contrast abdominal magnetic resonance imaging features can help clinicians evaluate the type of injury, severity, and poor prognosis of drug-induced liver injury. • Transient hepatic attenuation difference and ascites have potential clinical utility in the prediction of the poor prognosis of liver transplantation/liver-related death. • The new model predicting poor prognosis has a relatively high sensitivity of 0.875 and a high specificity of 0.919.

Lysosomal Adenosine Triphosphate-Activated Upconversion Nanoparticle/Carbon Dot Composite for Ratiometric Imaging of Hepatotoxicity.

Drug-induced hepatotoxicity (DIH) is a common cause of acute liver injury, endangering human health. Intracellular adenosine triphosphate (ATP) content in hepatocytes is related to hepatotoxicity. Thus, monitoring the dynamic changes in lysosomal ATP is promising to further understand the pathogenesis and accurate evaluation of DIH. Herein, we developed a lysosomal ATP-activated upconversion nanoprobe by decorating ATP-sensitive carbon dots (CDs) on the surface of upconversion nanoparticles (UCNPs) for ratiometric imaging of hepatotoxicity. Owing to the excellent optical characteristics of UCNPs as well as the high selectivity and biocompatibility of CDs, this nanoprobe showed robust reversibility and good sensitivity to ATP in an acidic environment. Noticeably, it was successfully applied in imaging the lysosomal ATP levels fluctuation in living cells and deep tissues and used for studying the production and remediation pathways of acetaminophen-induced hepatotoxicity. This nanoprobe is significant for further understanding the pathogenesis of DIH and may be a potentially effective tool for the clinical evaluation of DIH.

Optimizing phenyl selenide-based BODIPYs as fluorescent probes for diagnosing cancer and drug-induced liver injury via cysteine.

Herein, by optimizing phenyl selenide-based BODIPYs, BDP-Se-MOS was obtained, which possessed resistance to ROS and could selectively detect Cys. BDP-Se-MOS could not only discriminate between normal and cancer cells, but also image Cys levels in tumor-bearing mice in real time as well as image the fluctuations of Cys levels in an APAP-induced DILI model.

H2O2-Activated NIR-II Fluorescent Probe with a Large Stokes Shift for High-Contrast Imaging in Drug-Induced Liver Injury Mice.

Drug-induced liver injury (DILI) is the most common clinical adverse drug reaction, which is closely associated with the oxidative stress caused by overproduced reactive oxygen species. Hepatic H2O2, as an important biomarker of DILI, plays a crucial role in the progression of DILI. However, there remains a challenge to develop H2O2-activatable second near-infrared (NIR-II, 1000-1700 nm) small molecular probes with both a large Stokes shift and a long emission wavelength beyond 950 nm. Herein, we developed an activatable NIR-II fluorescent probe (IR-990) with an acceptor-π-acceptor (A-π-A) skeleton for real-time detection of H2O2 in vivo. In the presence of H2O2, nonfluorescent probe IR-990 was successfully unlocked by generating a donor-π-acceptor (D-π-A) structure and switched on intense NIR-II fluorescence, exhibiting a peak emission wavelength at 990 nm and a large Stokes shift of 200 nm. Moreover, it was able to detect H2O2 with high sensitivity and selectivity in vitro (LOD = 0.59 µM) and monitor the behavior of endogenous H2O2 in the HepG2 cell model of DILI for the first time. Notably, probe IR-990 was successfully applied in real-time imaging of endogenous H2O2 generation in the DILI mouse model, showing a high signal-to-background ratio of 11.3/1. We envision that IR-990 holds great potential as a powerful diagnosis tool for real-time visualization of H2O2 in vivo and revealing the mechanism of DILI in the future.

Mitochondria-Targeted Fluorescence/Photoacoustic Dual-Modality Imaging Probe Tailored for Visual Precise Diagnosis of Drug-Induced Liver Injury.

The multispectral optoacoustic tomography (MSOT) technique can be used to perform high-resolution molecular imaging under deep tissues, which gives the technology significant prospective for clinical application. Here, we developed a superoxide anion (O2•-)-activated MSOT and fluorescence dual-modality imaging probe (APSA) for early diagnosis of drug-induced liver injury (DILI). APSA can respond quickly to O2•-, resulting in an absorption peak blueshift from 845 to 690 nm, which also leads to the photoacoustic (PA) signal at 690 nm and the fluorescence signal at 748 nm increases linearly with increasing O2•- concentration, which can be utilized to assess the extent of liver damage. The developed MSOT imaging method can eliminate background interference from hematopoietic tissue by collecting the PA signals excited at 680, 690, 740, 760, 800, 845, and 900 nm wavelengths to achieve noninvasive in situ visual diagnosis of DILI. The developed fluorescence imaging method can be used for the imaging of endogenous O2•- in living cells and anatomic diagnosis of liver injury. The developed probe has broad application prospects in the early diagnosis of DILI.