In vivo microscopy

Abstract

This article summarizes the past, present, and future promise of multiphoton excitation fluorescence microscopy for intravital kidney imaging. During the past 15 years, several high-power visual research approaches have been developed using multiphoton imaging to study the normal functions of the healthy, intact, living kidney, and the various molecular and cellular mechanisms of the development of kidney diseases. In this review, the main focus will be on intravital multiphoton imaging of the glomerulus, the structure and function of the glomerular filtration barrier, especially the podocyte. Examples will be given for the combination of two powerful research tools, in vivo multiphoton imaging and mouse genetics using commercially available whole animal models for the detailed characterization of glomerular cell types, their function and fate, and for the better understanding of the molecular mechanisms of glomerular pathologies. One of the new modalities of multiphoton imaging, serial imaging of the same glomerulus in the same animal over several days will be emphasized for its potential for further advancing the field of nephrology research.

Value of multiphoton microscopy in uro-oncology: a narrative review

“…One of the possibilities of in vivo assessment with MPM could be the evaluation of ischemia-reperfusion injury (IRI) following a partial nephrectomy. Using time-lapse imaging, or imaging in vivo the same kidney for several days (43), MPM is able to demonstrate the development of acute tubular necrosis by picking up the flattening of the epithelium, swelling of lumen and shedding of the epithelial cells (44). MPM can also be used to detect certain tagged proteins and molecules by using antibodies against them (CD-44+ cells) (44).…”

Novel fluorescence techniques to quantitate renal cell biology

“…Changes in tissue architecture, cellular structure and anatomy have also been ascertained using classical histology and immunofluorescence techniques. In contrast to these traditional methods, MPM affords us the opportunity to study real-time changes in a living intact kidney in a nuanced and detailed fashion (Dunn et al, 2002;Molitoris & Sandoval, 2009;Peti-Peterdi, Kidokoro, & Riquier-Brison, 2015, 2016. In the initial years of applying MPM for renal tissue imaging, an inherent complication was limited imaging depth, since the kidney parenchyma is not as optically clear as other organs like the brain.…”

“…Since serial MPM involves visualizing the same area of the kidney tissue over time, this technique overcomes the issue of renal tissue heterogeneity. A combination of structural and functional measurements in vivo can thus help better understand the dynamics of renal pathophysiology at a single cell level that cannot be ascertained using whole organ measurements and histology techniques (Peti-Peterdi, 2016;Peti-Peterdi et al, 2016).…”

“…Earlier approaches involved classical histology-based techniques, cell culture-based model systems and electron microscopy. Although these methods are effective in providing a static understanding of renal cell biology, it is imperative to employ advanced techniques that provide non-invasive or minimally invasive imaging of the intact living kidney tissue in order to provide a deeper understanding of the dynamic nature of cell biology (Peti-Peterdi, 2016). Multiphoton microscopy (MPM), a term which encompasses both two-and threephoton microscopy, is one such experimental approach.…”