Scientists at the Tufts University School of Medicine in Boston have located a protein that may serve as the first molecular marker for the disease glaucoma, and may lead to the development of an early screening test for the disease. Dr. Joel Schuman and colleagues have discovered that the endothelial leukocyte adhesion molecule 1 (ELAM-1), a small cell adhesion molecule that is implicated in the development of vascular diseases, is present in the eyes of patients with glaucoma, but not present in healthy eyes.
The glaucomas, characterized by cupping of the optic nerve head and irreversible loss of retinal ganglion cells, comprise the leading cause of irreversible blindness worldwide. A major risk factor for development of the disease is elevated introcular pressure due to a reduction in normal aqueous outflow. The trabecular meshwork [TM] of the eye forms part of the outflow pathway for aqueous humour as it drains from the back of the eye. If the outflow of the humour is obstructed, the intraocular pressure may rise and glaucoma may occur. ELAM-1 was found to be consistently present on the TM cells in the outflow pathways of eyes with glaucomas of diverse etiology. This study provided the first evidence on a molecular marker for glaucoma, and the first evidence that common mechanisms contribute to the pathophysiology of the glaucomas and vascular diseases. It is believed that abnormalities in the genes encoding ELAM-1 may be considered to be a diagnostic marker of glaucoma, before any damaging rise in intraocular pressure is observed.
- Wang, N et al. Nature Medicine 2001;7:304-309.