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Abstract #15978 Published in IGR 2-3
Human ocular perfusion organ culture: a versatile ex vivo model for glaucomaresearch.
Pang IH; McCartney MD; Steely HT; Clark AFJournal of Glaucoma 2000; 9: 468-79
In this basic science review on human ocular perfusion organ culture the authors discuss the perfusion techniques. Under the heading of pathologic changes associated with ocular hypertension they mention perfusion of tissues from patients with primary open-angle glaucoma and glucocorticoid induced hypertension. They consider several outflow facility enhancers including epinephrine, matrix metalloproteinases, citoskeleton modifying agents, bumetanide, prostanoids and verapamil. They end their interesting review with new uses of perfusion organ culture such as proteomics and molecular biology. They reach the following conclusion: We have shown that the perfusion organ culture is a versatile in vitro system. It is useful as a research tool in answering various scientific questions. Because of the relative integrity of the TM, Schlemm's canal, and other components of the outflow pathway, this model is appropriate for understanding the physiology and biochemistry of IOP regulation. Ex vivo data thus obtained almost always reflect in vivo data, yet it is superior to in vivo assays in that physiologic parameters, such as flow rate, flow resistance, and IOP, can be easily correlated in the same perfused tissue with biochemical data, such as levels of extracellular matrix, trophic factors, cytokines, and other molecules. Morphologic changes of the perfused eyes, including the health of the various structures, TM cellularity, extracellular space in the juxtacanalicular and trabecular regions, and other morphometric measurements, have also provided additional information in the biology of outflow regulation. Furthermore, by using glaucomatous or glucocorticoid-treated eyes, this model system is a valuable tool for prying into the pathology of ocular hypertension. Again, physiologic, biochemical, morphologic, and recently, genetic techniques can be applied together in defining the relevant molecular mechanisms. In addition to its contribution to the understanding of glaucoma, the perfusion organ culture is also used to discover ways to intervene with the disease. As shown by examples of the pharmacologic compounds tested in this model, it is undoubtedly helpful in the assessment of various potential outflow enhancers. Results obtained in the perfused anterior segment will guide the future development of the next generation of outflow-oriented IOP-lowering drugs. Despite these advantages, however, the perfusion organ culture has several drawbacks. The limited availability of good-quality human donor tissues severely constrains the scale and scope of studies. A well-designed and extensive study may require a long time to accumulate enough data to address the various aspects of the working hypothesis. Furthermore, the delicate and complex nature of human eyes requires skillful technical handling and trouble-shooting throughout the dissection and perfusion processes, which makes it labor-intensive. We also found that postperfusion morphologic confirmation of the viability and health of the tissue, at least those related to the outflow pathway, is important in evaluating the validity of the data of each individual experiment. Therefore, electron microscopy is highly recommended as an integral component of the study design. This may be regarded as a resource-intensive for some laboratories. Nevertheless, although the perfusion organ culture can be costly in resources, labor, and time, the results generated are clinically meaningful and unparalleled by other study methods. It is therefore clearly worthy of the effort.
Alcon Research, Ltd., Fort Worth, Texas 76134, USA.
Classification:
3.4 Molecular genetics (Part of: 3 Laboratory methods)
