Bioengineering Studies of Transport across Bruch's Membrane

Mark Johnson, PhD
Northwestern University (Evanston, IL)
Year Awarded:
Grant Duration:
April 1, 2003 to March 31, 2005
Macular Degeneration
Award Amount:
Grant Reference ID:
Award Type:
Award Region:
US Midwestern

Bioengineering Studies of Transport across Bruch's Membrane


Bruch's membrane is a thin connective tissue layer that lies between the eye's choriocapillaris (minute blood vessels of the choroid layer) and the retinal pigment epithelium. Since the transport of nutrients to the retina and the disposal of waste products must pass through Bruch's membrane, the obstruction of transport through this tissue can have serious physiological consequences. It is known that the early stages of age-relate macular degeneration (AMD) are characterized by minor to moderate vision loss that is associated with debris accumulation, particularly the accumulation of lipids. Dr. Johnson and his colleagues are exploring the hypothesis that this accumulation of debris impairs the transport capacity of Bruch's membrane, leading to a progressive worsening of the condition. Because the only known risk factor for the early stages of macular degeneration is advanced age, it is important to understand how age-related changes in Bruch's membrane may predispose some individuals for lesion development. Dr. Johnson is using a bioengineering technique called quick freeze/deep etch to examine how the transport capacity of Bruch's membrane changes with age. The results of this study are expected to provide a firm quantitative basis for understanding the transport properties in Bruch's membrane of eyes that have macular degeneration, leading to the development of better treatments or even a means of preventing AMD. This project is a continuation of a Macular Degeneration Research study initiated in 2001.


Ethier, C.R., Johnson, M., and Ruberti, J. (2004) Ocular biomechanics and biotransport. Annual Review of Biomedical Engineering. 6:249-273.

Ruberti, J.W., Curcio, C.A., Millican, L., Menco, B.Ph.M., Huang, J.-D., and Johnson, M.: Quick-freeze/deep-etch visualization of age-related lipid accumulation in Bruch's membrane, Investigative Ophthalmology &Visual Science 44: 1753-1759, 2003.

Overby, D and Johnson, M: Studies of depth-of-field effects in microscopy supported by numerical simulations, The Journal of Microscopy, 220, part 3, 176-189, 2005. PubMed Icon Google Scholar Icon

Huang, J-D, Presley, JB, Chimento, MF, Curcio, CA and Johnson, M: Age-related changes in human macular Bruch's membrane as seen by quick-freeze/deep-etch, Experimental Eye Research, 85: 202-218, 2007.

Johnson, M, Dabholkar, A., Huang, J-D, Presley, J.B., Chimento, M.F. and Curcio, C.A.: Comparison of morphology of human macular and peripheral Bruch's membrane in older eyes, Current Eye Research, 32: 791-799, 2007.

Huang, J-D, Curcio, C.A. and Johnson, M: Morphometric analysis of lipoprotein-like particle accumulation in aging human macular Bruch's membrane, Investigative Ophthalmology &Visual Science, 49: 2721-2727, 2008.

McCarty, WJ, Chimento, MF, Curcio, CA and Johnson, M: Effects of particulates and lipids on the hydraulic conductivity of Matrigel(TM), Journal of Applied Physiology, 105: 621-628, 2008.

McCarty, WJ and Johnson, M: The hydraulic conductivity of Matrigel™, Biorheology, 44: 323-317, 2007. PubMed Icon Google Scholar Icon
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