| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| June 2006 | Inside IOVS | Volume 47/6 |
The Human Retinal and RPE Transcriptosome Catalogued by EyeSAGE
Bowes Rickman et al. (p. 2305) prepared a gene expression profile of the human macular and midperipheral retinal and retinal pigment epithelial/choroid transcriptosomes using the Serial Analysis of Gene Expression (SAGE) technique. EyeSAGE is an interactive tool and database for querying human retina and RPE gene expression that simplifies the process of extracting information from large gene expression datasets. For example, EyeSAGE users can compare the pattern of gene expression in the retina and RPE to multiple tissues in order to identify genes that are likely to be expressed in a single cell type such as the cone photoreceptor. In addition, the database can be used for Genomic Convergence—combining expression data with available linkage information to generate lists of candidate genes for diseases. The EyeSAGE database is available at NEIBank, where it is being integrated with the online tools for manipulation of gene expression data.
Lutein and Zeaxanthin: Risk for ARM and Cataract
Lutein and zeaxanthin are selectively accumulated in the retina, where they form the macular pigment, and in the lens. Delcourt et al. (p. 2329) show that high plasma levels of zeaxanthin are associated with a dramatic reduction in the risk of age-related maculopathy (93%) and of cataract (47%). Plasma lutein showed weaker associations with age-related maculopathy (ARM) and no association with cataract. These results suggest that xanthophylls, in particular zeaxanthin, may be useful for the protection against ARM and cataract.
Basement Membrane of Ex Vivo Expanded Limbal Corneal Epithelial Cells
It is generally assumed that retention of the basement membrane in amniotic membrane is important to achieve ex vivo expansion of corneal limbal progenitor cells on amniotic membrane. Li et al. (p. 2381) demonstrate that pre-existing basement membrane of amniotic membrane actually dissolves first before new basement membrane is laid down during explant culture of corneal limbus. New basement membrane deposits much faster and becomes more mature on intact amniotic membrane than on denuded amniotic membrane. Rapid basement membrane reassembly may be the hallmark of successful ex vivo expansion of corneal limbal progenitor cells.
Insulin-like Growth Factor-1: A Treatment for Strabismus?
Strabismus is a common disorder of binocular misalignment in all age groups. Anderson et al. (p. 2461) examined the use of insulin-like growth factor (IGF)-1 as a potential pharmacologic treatment for strengthening extraocular muscles (EOM). Adult rabbits received a single injection of IGF-1 at one of several doses into one superior rectus muscle. One week after these intramuscular injections with IGF-1, both muscle force generation and cross-sectional area were significantly increased at all doses tested in this study. Doses of 10 and 25 mg IGF-1 were most effective. Thus, direct muscular injection of IGF-1 can effectively increase EOM force generation without the potential biomechanical hazards of surgery such as permanently altered muscle length or insertional position on the globe.
Mitochondrial Abnormalities in POAG
Mitochondrial abnormalities have now been reported in several spontaneous optic neuropathies, including Leber hereditary optic neuropathy and dominant optic atrophy. Abu-Amero et al. (p. 2533) evaluated 27 patients with primary open-angle glaucoma (POAG), the most common optic neuropathy, for evidence of mitochondrial disease. Every patient had some type of mitochondrial abnormality, including potentially pathologic mitochondrial DNA changes in 14 and evidence of decreased mitochondrial function in 24. These results pose the possibility that mitochondrial abnormalities and oxidative stress may be risk factors for POAG. Awareness of mitochondrial problems in POAG may open additional avenues for investigation and treatment.
Recombinant TCR Ligands: Potential Treatment for Uveitis
Despite significant research efforts and advances in diagnosis and therapy, ocular autoimmune diseases remain significant causes of visual impairment in humans. In Adamus' et al. study (p. 2555), a novel methodology was explored for targeting pathogenic T cells to treat autoimmune uveitis. Recombinant TCR ligands (RTLs) inhibited clinical and histological uveitis by decreasing the activation of pathogenic T cells and preventing the recruitment of inflammatory cells into the eye. This study raises the possibility of application to treat clinical inflammation in the eye without adverse effects of currently used treatments.
Robust Imaging of Retinal Ion Demand In Vivo
There is a fundamental need in the study of the retina for a noninvasive imaging method capable of simultaneously and noninvasively monitoring neuronal activity in a layer-specific manner. Berkowitz et al. (p. 2668) have taken advantage of the fact that manganese ion is an essential metal, a surrogate for various ions including calcium, and a strong MRI contrast agent to measure layer-specific changes in ion demand during either light or dark adaptation in rats. The availability of this new tool is expected to benefit investigators studying a range of normal and pathologic retinal function.
Smooth Muscle Actin, Retinal Function and Vascular Development
Interaction of vascular smooth muscle (SM) cells and pericytes with endothelial cells is essential for normal vascular development. Tomasek et al. (p. 2693) used SM alpha-actin null mice to determine whether vascular SM and pericyte contractile function is necessary for retinal vascular development, normal blood-retinal barrier (BRB) permeability, and retinal function. They found that SM alpha-actin is not necessary for the formation of a normal retinal vascular pattern. However, it is necessary for normal BRB and retinal function. These studies demonstrate the importance of normal contractile function in SM cells and pericytes in the maintenance of the BRB and retina.
The Myopic Eye in Three Dimensions
Singh et al. (p. 2272) present a novel MRI acquisition, analysis and visualization technique for studying the complete 3-dimensional surface model of the human eye. The model can be freely rotated and color-coded with regard to morphological parameters, including distance from the posterior corneal pole and deviation from mean globe sphericity. The spatial accuracy and precision of axial length measurements using the model matches well those found with interferometry. In extending the range of biometric parameters that can be stratified and analyzed, the technique may be particularly valuable in defining further ocular structural correlates that underlie the onset and development of myopia.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |