Electron microscopy in renal pathology: overall applications and guidelines for tissue, collection, preparation, and stains

ABSTRACT

Electron microscopy is a mainstay in the analysis of renal biopsies, where it is typically employed in a correlative fashion along with light and immunofluorescence microscopy. Despite the development of a growing armamentarium of molecular and biochemical analytic methods as well as new immunostains with a widening panel of immunoreactants, electron microscopy remains crucial to the diagnosis of a number of disorders involving the renal glomerulus, vasculature, and tubulointerstitial compartment. The number of renal biopsies continues to grow and the indications for these biopsies continue expanding together with our understanding of disease processes. Proper collection of biopsies and careful analysis of data emanating from diagnostic modalities, clinical information, imaging, gross and microscopic tissue analysis, including a wide range of ancillary studies, represent the essential paradigm for generating detailed diagnoses with clinical significance. This communication offers a guide to the pre-analytic and analytic process for renal biopsy examination, discusses diagnostic keys and pitfalls for an important category of renal diseases (immune complex disorders), and provides an introduction to a useful adjunct diagnostic method (ultrastructural immunolabeling). Renal pathologists should render expert diagnoses that guide patient management, provide prognostic information and lead to targeted new therapeutic interventions that are currently available.

KEYWORDS:

• Electron microscopy
• renal biopsies
• sample preparation
• immunogold labeling
• kidney biopsy

Article highlights

• Good samples with cortical renal tissue to be submitted for light, immunofluorescence, and electron microscopy are required for a comprehensive evaluation of a kidney biopsy.

• Proper collection of renal biopsy specimens is paramount for accurate diagnosis.

• Electron microscopic evaluation plays an important diagnostic role in a significant number of cases, and this role has remained crucial for many years.

• Correlation of light, immunofluorescence, and ultrastructural findings is key for proper interpretation of a renal biopsy.

• Immunogold labeling in renal biopsies may provide additional information important for diagnosis and certain research projects.

Acknowledgments

The expert assistance of Ms. Susan Reeves with the preparation of the figures is gratefully acknowledged.

Declaration of interest

The authors have no conflicts of interest to report.

Additional information

Funding

The authors have no funding to report.