Article Text

PDF
An experimental study of the elastic properties of the human Bruch’s membrane-choroid complex: relevance to ageing
  1. M Ugarte,
  2. A A Hussain,
  3. J Marshall
  1. Department of Ophthalmology, Rayne Institute, St Thomas’s Hospital, London SE1 7EH, UK
  1. Correspondence to: Marta Ugarte Department of Ophthalmology, St Thomas’s Hospital, London SE1 7EH, UK; mugarte{at}doctors.org.uk

Abstract

Aim: To investigate the mechanical properties (stress-strain relation, elasticity, hysteresis, response to stress spikes and drops) of isolated human Bruch’s membrane-choroid, as well as the effect of ageing and aged related macular degeneration (AMD).

Methods: 13 Bruch’s membrane-choroid complexes were obtained from human donors (21–97 years). Two samples (aged 85 and 95) showed signs of AMD including large, soft drusen, choroidal neovascularisation, and/or disciform scars. Various hydrostatic pressures (stress) were applied to the choroidal surface of mid-peripheral samples mounted in a modified open Ussing chamber. Linear scans of the tissue were recorded by optical coherence tomography (OCT) and the pressure induced deformation (strain), elasticity, hysteresis, and response to pressure spikes and drops measured.

Results: The elasticity of human Bruch’s membrane-choroid complex decreased linearly with ageing (p<0.001) after the age of 21 with an approximate reduction of 1% per year. The decrease was not exaggerated in AMD. The recoil capacity of Bruch’s membrane-choroid was not affected by ageing. The response to pressure spikes/drops was similar in age matched normal and AMD eyes. The results suggest that although the aged induced decrease in Bruch’s membrane elasticity may contribute to breaks in this membrane in AMD leading to neovascularisation this is not sufficient. The presence of other factors is required for its development.

Conclusion: The elasticity of Bruch’s membrane-choroid complex decreases with age while recoil capacity does not. The decrease was not exaggerated in AMD.

  • AMD, aged related macular degeneration
  • ECM, extracellular matrix
  • PBS, phosphate buffered saline
  • OCT, optical coherence tomography
  • RPE, retinal pigment epithelium
  • Bruch’s membrane
  • elasticity
  • recoil
  • aged related macular degeneration
  • AMD, aged related macular degeneration
  • ECM, extracellular matrix
  • PBS, phosphate buffered saline
  • OCT, optical coherence tomography
  • RPE, retinal pigment epithelium
  • Bruch’s membrane
  • elasticity
  • recoil
  • aged related macular degeneration

Statistics from Altmetric.com

Footnotes

    Request permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.