This is a revised application by a new investigator to assess the role of inflammation in age-related maculopathy (ARM). ARM comprises the leading cause of incurable blindness among older adults in the US and other developed countries. However, the basic molecular pathways involved in the pathogenesis of ARM remain unknown, few potentially modifiable risk factors have been identified, and treatment remains inadequate. We hypothesize that the pathologic changes occurring in both the early and late stages of ARM are mediated by cells and molecules associated with inflammation and that the pro-inflammatory state that gives rise to these changes is at least in part a systemic rather than merely local phenomenon. The proposed studies will build upon a broadly based and growing body of research that supports a key role for inflammatory/immune-mediated processes in ARM pathogenesis. This research suggests several pathways through which inflammation could mediate the development of ARM, including RPE damage and repair, drusen formation, degeneration of Bruch's membrane, endothelial dysfunction in choroidal vessels, increased oxidative stress, decreased bioavailability of antioxidants, as well as the direct or indirect promotion of angiogenesis. Through its use of archived blood specimens from the Physicians' Health Study, Women's Health Study, women's Antioxidant Cardiovascular Disease Study, Nurses' Health Study, and Health Professionals Follow-up Study, this proposal represents an exceptionally cost-effective and efficient means to investigate the proposed hypothesis using a prospective nested case-control study design.
The Specific Aims are to investigate 1) the relationship of systemic markers /mediators of inflammation (IL-6, C-reactive protein, fibrinogen, haptoglobin, circulating adhesion molecules, and tumor necrosis factor-alpha receptors) with incident ARM, 2) the separate relationships of these inflammatory molecules with dry and neovascular ARM lesions, 3) whether the relationship of inflammation with ARM is independent of other risk factors such as cigarette smoking, and 4) the interrelationships among the biomarkers and which independendy predict incident ARM.
These aims will be accomplished through measurement using highly sensitive assays of inflammatory biomarkers in blood specimens collected at baseline (i.e. prior to the development of ARM) and stored since that time below -80?C. Biomarker levels will be compared among subjects who eventually developed ARM and control subjects who remained free of ARM, and the analysis will be extended to control for other risk factors. The long-term objective and clinical relevance of this research is to shed light on potential underlying biological mechanisms of ARM pathogenesis and suggest avenues for new preventive or therapeutic approaches, as well as to identify clinically useful biomarkers for identification of individuals at increased risk of ARM.
