We can see clearly now: optical clearing and kidney morphometrics

Area of Science:

• Nephrology
• Microscopy
• Biomedical Imaging

Background:

• Traditional kidney microscopic imaging relied on thin sections, leading to 2D morphometry that largely ignored tissue 3D structure.
• Stereological techniques, while addressing 3D, were often considered laborious and expensive for routine use.

Purpose of the Study:

• To review the development and application of optical clearing techniques for kidney tissue.
• To highlight how these methods enable advanced 3D kidney morphometrics.

Main Methods:

• Description of three main optical clearing strategies: solvent-based, aqueous-based, and hydrogel embedding.
• Discussion of the advantages and disadvantages of each clearing method.

Main Results:

• Optical clearing allows visualization of thick kidney slices and whole organs.
• New approaches to kidney morphometrics include quantifying atubular glomeruli, glomerular volume, podocyte numbers, and cell-specific stress markers like foot process effacement.

Conclusions:

• Optical clearing and new morphometric approaches offer a powerful toolkit for 3D kidney microanatomy imaging and quantification.
• These methods reduce reliance on biased 2D techniques and time-consuming stereology, accelerating structure-function research in healthy and diseased kidneys.