Mouse models may provide new insight into the relation between cholesterol and age related macular degeneration

Metabolism and Vascular Retinopathies: Current Perspectives and Future Directions

The retina is one of the most metabolically active organs in the body. Although it is an extension of the brain, the metabolic needs of the retina and metabolic exchanges between the different cell types in the retina are not the same as that of the brain. Retinal photoreceptors convert most of the glucose into lactate via aerobic glycolysis which takes place in their cytosol, yet there are immense numbers of mitochondria in photoreceptors. The present article is a focused review of the metabolic dysregulation seen in retinopathies with underlying vascular abnormalities with aberrant mitochondrial metabolism and Hypoxia-inducible factor (HIF) dependent pathogenesis. Special emphasis has been paid to metabolic exchanges between different cell types in retinopathy of prematurity (ROP), age-related macular degeneration (AMD), and diabetic retinopathy (DR). Metabolic similarities between these proliferative retinopathies have been discussed.

Cardiovascular Risk Factors and the Long-term Incidence of Age-Related Macular Degeneration

PURPOSE

To assess the relationship between cardiovascular disease and cardiovascular risk factors, other than smoking, and risk of long-term incident age-related macular degeneration (AMD).

DESIGN

Population-based cohort study.

PARTICIPANTS

There were 3654 baseline (1992-1994) participants aged > or = 49 years included in the Blue Mountains region, west of Sydney, Australia. Of these, 2335 (75% of survivors) were reexamined after 5 years (1997-1999) and 1952 (76% of survivors) after 10 years (2002-2004).

METHODS

Stereoscopic color fundus photographs were graded using the Wisconsin Age-related Maculopathy Grading System. History, physical examination, and fasting blood samples provided data on possible risk factors. Age-related macular degeneration incidence was calculated using the Kaplan-Meier survival approach. Discrete linear logistic models were used to assess risk of incident AMD. Relative risks (RR) and 95% confidence intervals (CI) are presented after adjusting for age, gender, smoking, and other risk factors.

MAIN OUTCOME MEASURE

Incident early and late AMD.

RESULTS

Increasing high-density lipoprotein (HDL) cholesterol was inversely related to incident late AMD (RR per standard deviation [SD] increase, 0.74; 95% CI, 0.56-0.99). Elevated total/HDL cholesterol ratio predicted late AMD (RR per SD increase, 1.35; 95% CI, 1.07-1.70) and geographic atrophy (GA; RR per SD, 1.63; 95% CI, 1.18-2.25). Diabetes predicted incident GA (RR, 3.89; 95% CI, 1.36-11.08), but not neovascular AMD. History of stroke (RR 2.01; 95% CI, 1.12-3.58), or any cardiovascular disease (stroke, myocardial infarction, or angina; RR, 1.57; 95% CI, 1.13-2.16) predicted incident early AMD and incident indistinct soft or reticular drusen (RR, 2.38; 95% CI, 1.33-4.27 for stroke; RR, 1.80; 95% CI, 1.28-2.52 for any cardiovascular disease). Neither pulse pressure, systolic or diastolic blood pressure, or presence of hypertension at baseline were associated with incident AMD.

CONCLUSIONS

Our findings provide some evidence of links between cardiovascular risk factors and AMD. Further prospective evaluation of these relationships is warranted, as these findings could have therapeutic implications.