In vivo imaging of systemic transport and elimination of xenobiotics and endogenous molecules in mice

Raymond Reif,Jan G Hengstler,Paul M Kaye,Georgia Günther,Lynette Beattie,Ahmed Ghallab,Lars Kuepfer

doi:10.1007/s00204-016-1906-5

Abstract

We describe a two-photon microscopy-based method to evaluate the in vivo systemic transport of compounds. This method comprises imaging of the intact liver, kidney and intestine, the main organs responsible for uptake and elimination of xenobiotics and endogenous molecules. The image quality of the acquired movies was sufficient to distinguish subcellular structures like organelles and vesicles. Quantification of the movement of fluorescent dextran and fluorescent cholic acid derivatives in different organs and their sub-compartments over time revealed significant dynamic differences. Calculated half-lives were similar in the capillaries of all investigated organs but differed in the specific sub-compartments, such as parenchymal cells and bile canaliculi of the liver, glomeruli, proximal and distal tubules of the kidney and lymph vessels (lacteals) of the small intestine. Moreover, tools to image immune cells, which can influence transport processes in inflamed tissues, are described. This powerful approach provides new possibilities for the analysis of compound transport in multiple organs and can support physiologically based pharmacokinetic modeling, in order to obtain more precise predictions at the whole body scale.

Highlights

First-in-human trials represent a critical step in drug development due to interspecies differences between humans and the animal species in which preclinical research is performed
It was shown that advanced techniques of physiologically based pharmacokinetic (PBPK) modeling improved the accuracy of extrapolation from mouse to human (Thiel et al 2015)
Two-photon microscopy offers the possibility to study processes with fast kinetics that are impossible to analyze by conventional histology

Summary

Introduction

First-in-human trials represent a critical step in drug development due to interspecies differences between humans and the animal species in which preclinical research is performed. Only little is known about transport kinetics in sub-compartments within liver, kidney and intestine, because they have been difficult to analyze due to their structural complexity and the rapid kinetics of the processes involved These difficulties may be overcome by the integration of data achieved via intravital two-photon imaging into PBPK models. A specific strength of two-photon microscopy, developed in the early nineteen nineties, is the possibility to image deeply into living tissues (Denk et al 1990; Pittet and Weissleder 2011) This technique has been applied to study various biological processes in living organs, e.g., sterile tissue destruction by toxins (Marques et al 2015a), pathogen infection (Beattie et al 2013), tumor cell migration (Wolf et al 2003), behavior of immune cells (Lammermann et al 2013) as well as endocytosis (Masedunskas and Weigert 2008). The technique we describe facilitates in vivo recording to study systemic transport and excretion processes in the most important organs

Materials and methods

Surgical procedure

Results