Advances in intravital microscopy for monitoring cell flow dynamics in vivo

The use of small animals in intravital optical microscopy is a well-established experimental model to study blood microcirculation <i>in vivo</i>. Recent advances in cell biology and optical techniques (e.g., lasers, CCD cameras, software, etc.) provide the basis for significant improvements with <i>in vivo </i>imaging. This review summarizes the latest achievements in this specific area focusing on the development of modern optical and biological platforms. This includes in vivo real time monitoring of individual cells in the context of blood flow, super-sensitive fluorescence imaging, high-speed cell imaging and light scattering techniques. The capability of these platforms has been demonstrated in live animal models (e.g., mouse and rat ear, rat mesentery, and others) for real-time monitoring of individual blood cell properties (e.g., size and shape), cell trafficking, cell-cell interactions (e.g., aggregation in flow or adhesion to vessel walls), and blood flow viscosity. Future applications are discussed including <i>in vivo </i>early diagnosis of disease and monitoring cellular responses to environmental and therapeutic interventions.