Letter to the Editor: Intravital Dynamic and Correlative Imaging Reveals Diffusion-Dominated Canalicular and Flow-Augmented Ductular Bile Flux

The report by Vartak et al uses a new technique for evaluating hepatic bile formation. They conclude that canalicular water flow does not occur, thus challenging the Sperber hypothesis. The validity of their technique for studying canalicular water flow awaits confirmation in other laboratories. Also, the investigators need to address the many reported studies that support the Sperber hypothesis.