title: Automated quantification of renal fibrosis with Sirius Red and polarization contrast microscopy.
abstract: Interstitial fibrosis is commonly measured by histology. The Masson trichrome stain is widely used, with semiquantitative scores subjectively assigned by trained operators. We have developed an objective technique combining Sirius Red staining, polarization contrast microscopy, and automated analysis. Repeated analysis of the same sections by the same operator (r = 0.99) or by different operators (r = 0.98) was highly consistent for Sirius Red, while Masson trichrome performed less consistently (r = 0.61 and 0.72, respectively). These techniques performed equally well when comparing sections from the left and right kidneys of mice. Poor correlation between Sirius Red and Masson trichrome may reflect different specificities, as enhanced birefringence with Sirius Red staining is specific for collagen type I and III fibrils. Combining whole-section imaging and automated image analysis with Sirius Red/polarization contrast is a rapid, reproducible, and precise technique that is complementary to Masson trichrome. It also prevents biased selection of fields as fibrosis is measured on the entire kidney section. This new tool shall enhance our search for novel therapeutics and noninvasive biomarkers for fibrosis.
authors: Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
authors: Jonathan M
authors: JM
authors: Street
authors: Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
authors: Ana Carolina P
authors: AC
authors: Souza
authors: Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
authors: Alejandro
authors: A
authors: Alvarez-Prats
authors: Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
authors: Taro
authors: T
authors: Horino
authors: Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
authors: Xuzhen
authors: X
authors: Hu
authors: Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
authors: Peter S T
authors: PS
authors: Yuen
authors: Renal Diagnostics and Therapeutics Unit, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
authors: Robert A
authors: RA
authors: Star
keywords: Chronic kidney disease; Masson trichrome; fibrosis