Gene expression profiling using cDNA microarrays

Background. Our knowledge about the molecular and gene m ic background of diseases has expanded dramatically in the recent past and cDNA microarrays now provide the opportunity to simultaneously analyse the expression of thousands of genes. This could pave the way towards a systematic exploration of the pathogenetic principle of ophthalmological diseases which could lead to the identifcation of key disease-specific molecules that will be useful as diagnostic marker or serve as therapeutic targets. Materials and methods. Various strategies for cDNA microarray analysis are reviewed, including different commercially available arrays (microarrays on glass and arrays on nylon filters) as well as methods for analysing the unprecedented large amounts of data from a single experiment. Possible applications for research and clinical applications in ophthalmology are discussed. Results. The cDNA microarray-based technology allows the rapid and cost-effective screening of gene expression without a priori knowledge about which gene might be of interest. Here, we discuss how the analysis of gene expression as whole profiles instead of the conventional focus on an individual gene may offer new insights into the fundamental nature of the pathogenesis of complex diseases using the example of early diabetic retinopathy. Conclusion. To date,the gene-array technology is still largely a laboratory procedure and has not yet been used in the clinical setting. However, in clinically oriented basic research, it will a allow a more encompassing analysis of disease processes and thus lead to the identification of important diagnostic tools and potential drug targets in ophthalmological diseases.