June 2023
Volume 64, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2023
Early life trabecular meshwork pathology associated with LTBP2 mutation in a feline model of primary congenital glaucoma (PCG)
Author Affiliations & Notes
  • Odalys Torne
    Ophthalmology and Visual Sciences, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, United States
    Surgical Sciences - School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States
  • Kazuya Oikawa
    Ophthalmology and Visual Sciences, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, United States
    Surgical Sciences - School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States
  • Leandro Teixeira
    Pathobiological Sciences - School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States
  • Julie Kiland
    Ophthalmology and Visual Sciences, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, United States
  • Gillian J McLellan
    Ophthalmology and Visual Sciences, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, United States
    Surgical Sciences - School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States
  • Footnotes
    Commercial Relationships   Odalys Torne None; Kazuya Oikawa None; Leandro Teixeira None; Julie Kiland None; Gillian McLellan None
  • Footnotes
    Support  La Caixa Foundation LCF/BQ/AA20/11820026, The Marfan Foundation, Research to Prevent Blindness, NIH Grants P30 EY016665 and S10 OD018221 and the McPherson Eye Research Institute University of Wisconsin-Madison.
Investigative Ophthalmology & Visual Science June 2023, Vol.64, 3461. doi:
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    • Get Citation

      Odalys Torne, Kazuya Oikawa, Leandro Teixeira, Julie Kiland, Gillian J McLellan; Early life trabecular meshwork pathology associated with LTBP2 mutation in a feline model of primary congenital glaucoma (PCG). Invest. Ophthalmol. Vis. Sci. 2023;64(8):3461.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : To characterize early changes in trabecular meshwork (TM) ultrastructure and ECM components in cats with PCG due to mutation in LTBP2.

Methods : Eyes from 21 cats homozygous for LTBP2 mutation and 19 age-matched control cats were examined at birth, 2wks, 5wks and 10-12wks of age by transmission electron microscopy (TEM) of anterior segment tissue, and by immunolabeling of LTBP2, laminin (LAM), fibronectin (FN1), fibrillin-1 (FBN1), fibrillin-2 (FBN2), elastin (ELN), fibulin-5 (FBLN5) and collagen I (COL-1) in cryosections. TEM and epifluorescence microscopy images were analyzed with ImageJ software and fluorescence intensity and morphometric features compared between groups by ANOVA (Graphpad Prism 9).

Results : The earliest changes in ECM composition in the TM are identifiable at 2wks postnatally in PCG cats, preceding the earliest observed changes in TM morphology, identifiable in 5wk old PCG cats. LTBP2 expression is absent in PCG cats at all ages, whereas LTBP2 expression pattern is generalized across the sclera at the time of birth, but confined to the TM and ciliary body in normal cats by 2wks of age. At 2wks, there is significantly lower expression of FBN1 (P=0.03), FBN2 (P=0.01) and ELN (P<0.0001) in the TM region in PCG relative to normal cats. FN1 (P=0.04), COL-1 (P=0.01) and FBN1 (P=0.02) expression in TM is significantly greater at 12wks of age in PCG relative to age-matched normal cats. TM morphometric and ultrastructural abnormalities are observable at 5wks of age in cats with PCG in which TM elastic fibers appear discontinuous and disorganized; there is significantly reduced intertrabecular space (ITS) (P=0.01) and TM cell shape is rounder (P=0.01) relative to age-matched controls . By 12wks of age there is progressive collapse of ITS (P=0.0006) and TM cell shape is more elongated in PCG compared to controls (P=0.0009).

Conclusions : In this model of PCG due to LTBP2 mutation, TM ECM pathology is not appreciable at birth but can be observed by 2wks postnatally, and changes in TM morphology are evident by 5wks and are well-established by 12wks of age, when IOP is significantly elevated in this model. These findings suggest that LTBP2 plays a critical role in postnatal TM development between birth and 5wks of age in cats, and to glaucoma development and progression observed in cats with LTBP2 mutation.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

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