Color Doppler Imaging of Choroidal Circulation in Patients with Asymmetric Age-Related Macular Degeneration

Purpose The aim of this study was to assess hemodynamic changes in the retrobulbar circulation in patients with age-related macular degeneration (ARMD). Methods Color Doppler imaging was used to calculate blood flow velocities and vascular resistance of the central retinal artery, short posterior ciliary artery and ophthalmic artery in patients with ARMD and in control patients. Results The average peak systolic velocity was significantly lower in the central retinal artery (p < 0.001), posterior ciliary artery (p < 0.001) and ophthalmic artery (p < 0.01) of the patients with ARMD than in control. End-diastolic blood flow velocities in the retrobulbar arteries of ARMD patients were also significantly lower (p < 0.001) than controls. Gosling's pulsatility index was significantly higher in the ophthalmic artery (p<0.01) and posterior ciliary artery (p < 0.001) of eyes with ARMD. In addition, the resistivity index was significantly higher in all retrobulbar arteries (p < 0.001) of these patients. Conclusions The hemodynamic abnormalities in the retrobulbar circulation suggest that vascular impairment may play a role in the pathogenesis of ARMD.

Download Full-text

Evaluation of Orbital Blood Flow in Age-Related Macular Degeneration by Color Doppler Ultrasonography

Van Medical Journal ◽

10.5505/vtd.2020.45656 ◽

2020 ◽

Vol 27 (2) ◽

pp. 177-183

Author(s):

Mine Karahan ◽

Deniz Kilic ◽

Mehmet Emin Dursun ◽

Birgül Dursun ◽

Aslı Uğurlu ◽

...

Keyword(s):

Blood Flow ◽

Macular Degeneration ◽

Doppler Ultrasonography ◽

Color Doppler ◽

Color Doppler Ultrasonography ◽

Age Related Macular Degeneration ◽

Age Related

Download Full-text

Is Retinal Metabolic Dysfunction at the Center of the Pathogenesis of Age-related Macular Degeneration?

International Journal of Molecular Sciences ◽

10.3390/ijms20030762 ◽

2019 ◽

Vol 20 (3) ◽

pp. 762 ◽

Cited By ~ 23

Author(s):

Thierry Léveillard ◽

Nancy Philp ◽

Florian Sennlaub

Keyword(s):

Macular Degeneration ◽

Aerobic Glycolysis ◽

Tricarboxylic Acid Cycle ◽

Retinal Pigment ◽

Basolateral Membrane ◽

Age Related Macular Degeneration ◽

Subretinal Space ◽

Outer Retina ◽

Choroidal Circulation ◽

Age Related

The retinal pigment epithelium (RPE) forms the outer blood–retina barrier and facilitates the transepithelial transport of glucose into the outer retina via GLUT1. Glucose is metabolized in photoreceptors via the tricarboxylic acid cycle (TCA) and oxidative phosphorylation (OXPHOS) but also by aerobic glycolysis to generate glycerol for the synthesis of phospholipids for the renewal of their outer segments. Aerobic glycolysis in the photoreceptors also leads to a high rate of production of lactate which is transported out of the subretinal space to the choroidal circulation by the RPE. Lactate taken up by the RPE is converted to pyruvate and metabolized via OXPHOS. Excess lactate in the RPE is transported across the basolateral membrane to the choroid. The uptake of glucose by cone photoreceptor cells is enhanced by rod-derived cone viability factor (RdCVF) secreted by rods and by insulin signaling. Together, the three cells act as symbiotes: the RPE supplies the glucose from the choroidal circulation to the photoreceptors, the rods help the cones, and both produce lactate to feed the RPE. In age-related macular degeneration this delicate ménage à trois is disturbed by the chronic infiltration of inflammatory macrophages. These immune cells also rely on aerobic glycolysis and compete for glucose and produce lactate. We here review the glucose metabolism in the homeostasis of the outer retina and in macrophages and hypothesize what happens when the metabolism of photoreceptors and the RPE is disturbed by chronic inflammation.

Download Full-text