title: Second harmonic microscopy to quantify renal interstitial fibrosis and arterial remodeling.
abstract: Interstitial fibrosis is a powerful pejorative predictor of progression of nephropathies in a variety of chronic renal diseases. It is characterized by the depletion of kidney cells and their replacement by extracellular matrix, in particular, type-I fibrillar collagen, a protein scarce in normal interstitium. However, assessment of fibrosis remains a challenge in research and clinical pathology. We develop a novel methodology based on second harmonic generation (SHG) microscopy, and we image collagen fibers in human and mouse unstained kidneys. We take into account the variability in renal shape, and we develop automated image processing for quantitative scoring of thick murine tissues. This approach allows quantitative 3-D imaging of interstitial fibrosis and arterial remodeling with high accuracy. Moreover, SHG microscopy helps to raise pathophysiological questions. First, imaging of a large volume within a mouse kidney shows that progression of fibrosis is a heterogeneous process throughout the different renal compartments. Second, SHG from fibrillar collagens does not overlap with the glomerular tuft, despite patent clinical and experimental glomerulosclerosis. Since glomerulosclerosis involves SHG-silent nonfibrillar collagens, our work supports pathophysiological differences between interstitial fibrosis and glomerulosclerosis, a clearly nonfibrotic process.
authors.affiliation: CNRS, Ecole Polytechnique, Laboratoire d'Optique et Biosciences, 91128 Palaiseau France.
authors.forename: Mathias
authors.initials: M
authors.lastname: Strupler
authors.forename: Monica
authors.initials: M
authors.lastname: Hernest
authors.forename: Cécile
authors.initials: C
authors.lastname: Fligny
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Martin
authors.forename: Pierre-Louis
authors.initials: PL
authors.lastname: Tharaux
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Schanne-Klein
mesh_terms: D000818:Animals; D005355:Fibrosis; D006801:Humans; D006977:Hypertension, Renal / Q000473:pathology*; D007668:Kidney / Q000098:blood supply* / Q000473:pathology*; D007674:Kidney Diseases / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D012077:Renal Artery / Q000473:pathology*