Visual method for evaluating liver function: targeted in vivo fluorescence imaging of the asialoglycoprotein receptor

In vivo evaluation of liver function by multimodal imaging in an alcohol-induced liver injury model

Background

Visually evaluating liver function is a hot topic in hepatology research. There are few reliable and practical visualization methods for evaluating the liver function in vivo in experimental studies. In this study, we established a multimodal imaging approach for in vivo liver function evaluation and compared healthy mice with chronic alcoholic liver injury (cALI) model mice to explore its potential applicability in experimental research.

Methods

In vivo fluorescence imaging (IVFI) technology was utilized to visually represent the clearance of indocyanine green from the liver of both healthy mice and mice with cALI. The reserve liver function was evaluated via IVFI using the Cy5.5-galactosylated polylysine probe, which targets the asialoglycoprotein receptor of hepatocytes. Hepatic microcirculation was assessed through laser speckle perfusion imaging of hepatic blood perfusion. The liver microstructure was then investigated by in vivo confocal laser endomicroscopy imaging. Finally, hepatic asialoglycoprotein receptor expression, histology, and the levels of serum alanine aminotransferase and aspartate aminotransferase were measured.

Results

In vivo multimodal imaging results intuitively and dynamically showed that indocyanine green clearance [mean ± standard deviation (SD): 30.83±14.71, 95% confidence interval (CI): 20.3 to 41.35], the fluorescence signal intensity (mean ± SD: 1,217.92±117.63; 95% CI: 1,148.38 to 1,290.84) and fluorescence aggregation area (mean ± SD: 5,855.80±1,271.81; 95% CI: 5,051.57 to 6,653.88) of Cy5.5-galactosylated polylysine targeting the asialoglycoprotein receptor, and hepatic blood perfusion (mean ± SD: 1,494.86±299.33; 95% CI: 1,316.98 to 1,690.16) in model mice were significantly lower than those in healthy mice (all P<0.001). Compared to healthy mice, the model mice exhibited a significant decline in liver asialoglycoprotein receptor expression (mean ± SD: 219.03±16.34; 95% CI: 208.97 to 230.69; P<0.001), increased serum alanine aminotransferase (mean ± SD: 149.70±47.89 U/L; 95% CI: 81.75 to 128.89; P=0.01) and aspartate aminotransferase levels (mean ± SD: 106.30±36.13 U/L; 95% CI: 122.01 to 180.17; P=0.021), hepatocyte swelling and deformation, disappearance of the hepatic cord structure, partial necrosis, and disintegration of hepatocytes. The imaging features of fluorescence signals in liver regions, hepatic blood perfusion and microstructure were biologically related to hepatic asialoglycoprotein receptor expression, serum indices of liver function, and histopathology in model mice.

Conclusions

Utilizing in vivo multimodal imaging technology to assess liver function is a viable approach for experimental research, providing dynamic and intuitive visual evaluations in a rapid manner.

Imaging Techniques in Pharmacological Precision Medicine

Biomedical imaging is a powerful tool for medical diagnostics and personalized medicines. Examples of commonly used imaging modalities include Positron Emission Tomography (PET), Ultrasound (US), Single Photon Emission Computed Tomography (SPECT), and hybrid imaging. By combining these modalities, scientists can gain a comprehensive view and better understand physiology and pathology at the preclinical, clinical, and multiscale levels. This can aid in the accuracy of medical diagnoses and treatment decisions. Moreover, biomedical imaging allows for evaluating the metabolic, functional, and structural details of living tissues. This can be particularly useful for the early diagnosis of diseases such as cancer and for the application of personalized medicines. In the case of hybrid imaging, two or more modalities are combined to produce a high-resolution image with enhanced sensitivity and specificity. This can significantly improve the accuracy of diagnosis and offer more detailed treatment plans. In this book chapter, we showcase how continued advancements in biomedical imaging technology can potentially revolutionize medical diagnostics and personalized medicine.

Effects of electroacupuncture on liver function in mice with chronic alcoholic liver injury: visual display by in vivo fluorescence imaging

OBJECTIVE

Acupuncture can improve the symptoms of alcohol-induced bodily injury and has been accepted by the World Health Organization. In this study, in vivo fluorescence imaging (IVFI) was applied to display and evaluate the effect of electroacupuncture (EA) on liver function (LF) in mice with chronic alcoholic liver injury (cALI).

METHODS

IVFI of the Cy5.5-galactosylated polylysine (Cy5.5-GP) probe targeting the liver asialoglycoprotein receptor (ASGPR) and liver indocyanine green (ICG) clearance was performed to visually evaluate the effect of EA at ST36 and BL18 on liver reserve function and hepatic metabolism in mice with cALI. In addition, changes in ASGPR expression, serum indexes of LF, and hepatic morphology were observed.

RESULTS

After EA at ST36 and BL18, the ASGPR-targeted fluorescence signals (FS) in the liver increased significantly in cALI mice (p < 0.05) and exhibited relationships with liver ASGPR expression, liver ICG clearance, liver histology, and serum marker levels of LF in cALI mice undergoing EA intervention.

CONCLUSIONS

As displayed by IVFI, EA at ST36 and BL18 appears to improve liver reserve function and inhibit the development of liver injury in mice with cALI. EA may have potential as a treatment strategy to protect against ALI.

Anti-cancer activity of sustained release capsaicin formulations

Capsaicin (trans-8-methyl-N-vanillyl-6-noneamide) is a hydrophobic, lipophilic vanilloid phytochemical abundantly found in chili peppers and pepper extracts. Several convergent studies show that capsaicin displays robust cancer activity, suppressing the growth, angiogenesis and metastasis of several human cancers. Despite its potent cancer-suppressing activity, the clinical applications of capsaicin as a viable anti-cancer drug have remained problematic due to its poor bioavailability and aqueous solubility properties. In addition, the administration of capsaicin is associated with adverse side effects like gastrointestinal cramps, stomach pain, nausea and diarrhea and vomiting. All these hurdles may be circumvented by encapsulation of capsaicin in sustained release drug delivery systems. Most of the capsaicin-based the sustained release drugs have been tested for their pain-relieving activity. Only a few of these formulations have been investigated as anti-cancer agents. The present review describes the physicochemical properties, bioavailability, and anti-cancer activity of capsaicin-sustained release agents. The asset of such continuous release capsaicin formulations is that they display better solubility, stability, bioavailability, and growth-suppressive activity than the free drug. The encapsulation of capsaicin in sustained release carriers minimizes the adverse side effects of capsaicin. In summary, these capsaicin-based sustained release drug delivery systems have the potential to function as novel chemotherapies, unique diagnostic imaging probes and innovative chemosensitization agents in human cancers.