In vivo real-time imaging of the liver with confocal endomicroscopy permits visualization of the temporospatial patterns of hepatocyte apoptosis

Medical Clinic, University of Mainz, Germany.
AJP Gastrointestinal and Liver Physiology (Impact Factor: 3.8). 07/2011; 301(5):G764-72. DOI: 10.1152/ajpgi.00175.2011
Source: PubMed


Apoptosis is a dynamic process of programmed cell death and is involved in multiple diseases. However, its mechanisms and sequence of events are still incompletely understood, partly because of the inability to visualize single cells continuously in vivo. The aim of the present study was to monitor hepatocyte apoptosis with confocal endomicroscopy in living rodents. In 73 anaesthetized mice, apoptotic liver injury was induced by injection of the CD95-agonistic antibody Jo2. Individual hepatocytes were followed for up to 240 min with a handheld confocal probe (FIVE1; Optiscan) providing 0.7 μm resolution (1,000-fold magnification). Different fluorescence staining protocols were used for cellular staining, vascular and cellular barrier function imaging, and caspase activation visualization. The time course of apoptosis could be visualized in vivo while liver perfusion and tissue integrity were maintained. In contrast to most ex vivo studies, initial cell swelling was observed that coincided with early defects in barrier function of sinusoids and hepatocytes. Cytoplasmic vesicle formation, nuclear condensation, cellular disintegration, and macrophage infiltration were captured sequentially. Labeling of caspases allowed molecular imaging. Our study allowed for the first time to continuously follow distinct morphological, functional, and molecular features of apoptosis in a solid organ in vivo and at high resolution. Intravital confocal microscopy may be a valuable tool to study the effects of therapeutic intervention on apoptosis in animal models and humans.

20 Reads
  • Source
    • "Apoptotic indices in individual ducks were counted in haematoxylin and eosin stained sections (data not shown) and were found to be in the range of 0.005–0.2%, which might contribute a maximum daily cell death rate of about 2% (Goetz et al., 2011). However, cell death would decrease levels of cccDNA and decrease the relative contribution of loss of cccDNA at mitosis. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Nucleos(t)ide analogues that inhibit hepatitis B virus (HBV) DNA replication are typically used as monotherapy for chronically infected patients. Treatment with a nucleos(t)ide analogue eliminates most HBV DNA replication intermediates and produces a gradual decline in levels of covalently closed circular DNA (cccDNA), the template for viral RNA synthesis. It remains uncertain if levels of cccDNA decline primarily through hepatocyte death, or if loss also occurs during hepatocyte mitosis. To determine if cccDNA survives mitosis, growing ducklings infected with duck hepatitis B virus (DHBV) were treated with the nucleoside analogue, Entecavir. Viremia was suppressed at least 10(5)-fold, during a period when average liver mass increased 23-fold. Analysis of the data suggested that if cccDNA synthesis was completely inhibited, at least 49% of cccDNA survived hepatocyte mitosis. However, there was a large duck-to-duck variation in cccDNA levels, suggesting that low level cccDNA synthesis may contribute to this apparent survival through mitosis.
    Preview · Article · Nov 2013 · Virology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Confocal laser endomicroscopy (CLE) is a novel imaging modality providing in vivo histology and allowing capture of very high-resolution images of human and animal liver. The manuscript from Goetz and colleagues in this issue of American Journal of Physiology GI and Liver, used CLE to continuously follow distinct morphological, functional and molecular features of apoptosis in intact liver in vivo and at high resolution. This new technology allowed the authors to make several important observations whilst highlighting the enormous promise of this technology for future in vivo studies of hepatic apoptosis and its pharmacological manipulation in animals and humans.
    Full-text · Article · Aug 2011 · AJP Gastrointestinal and Liver Physiology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Confocal laser endomicroscopy (CLE) is a novel tool in the endoscopist’s armamentarium. It allows on-site histological information. The ability of gastroenterologists to interpret such microscopic information has been demonstrated in multiple studies from the upper and lower gastrointestinal tract. Recently, the field of application has expanded to provide hepatobiliary and intra-abdominal CLE imaging. CLE allows “smart,” targeted biopsies and is able to guide endoscopic interventions. But CLE is also translational in its approach and permits functional imaging that significantly impacts on our understanding of gastrointestinal diseases. Molecular imaging with CLE allows detection and characterization of lesions and may even be used for prediction of response to targeted therapy. This paper provides a comprehensive review over current applications of CLE in clinical applications and translational science.
    Full-text · Article · Dec 2012
Show more