g., diet, physical

activity, and smoking) may affect the morphology of the retinal vasculature. Being easily accessible and non-invasively visualized, the retinal microvasculature therefore can be a clinically useful biomarker of reversible sub-clinical physiologic deviation of the systemic circulation as results of such unfavorable exposures. Importantly, quantitative analysis of the retinal microvasculature may be utilized as a prognostic tool, allowing for targeted vascular therapies before the NVP-BGJ398 clinical trial onset of overt cardiovascular and metabolic disorders. This review summarizes the modifiable lifestyle and environmental risk factors that affect retinal microvascular structure and the possible clinical implications of such relationships. The retinal microcirculation may reflect healthy and pathophysiologic processes affecting systemic

circulation [64]. The vascular architecture within the retina, as well as elsewhere in the body, is thought to follow the principles of optimality, which allows the blood distribution to peripheral tissue within the quickest time with the least amount of energy [45,65]. Therefore, deviations from optimal structure of the retinal vasculature (e.g., arteriolar narrowing, venular widening) may represent deviation of the circulation from its optimal state, indicating any pathophysiologic processes. During the last few decades, the retinal vasculature has received increasing attention. With the advancement of retinal imaging, the retinal vasculature may allow non-invasive visualization to examine and monitor human circulation systems in vivo buy Ku-0059436 (Figure 1). For example, computer-based analysis techniques from digital retinal images has allowed accurate and reproducible measurement Idoxuridine of several parameters of the retinal vasculature (e.g.,

caliber, fractal dimension [complexity of vessel network], and branching angle) [6,11,41,61,62]. A number of large-scale epidemiological studies have demonstrated that subtle changes in these parameters carry important information regarding the future risk of systemic vascular diseases [18,25,30,39,40,50,58,60,62]. Importantly, changes in the retinal vasculature have also been shown to have strong associations with systemic and environmental cardiovascular risk factors in a range of populations (for review see Ref. [51]), even before the clinical manifestation of diseases. These subtle retinal vascular changes have been suggested to mirror preclinical changes in both the cerebral [32] and coronary [53] microcirculations. Although the mechanisms remain questionable, this may indicate that abnormalities in the retinal vasculature incorporate a cumulative effect of systemic damage. Recently, many of the largest determinants of this sub-optimal retinal microvasculature have been found to be modifiable [40], such as diet and medications.