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Konstantin E Kotliar, Chiristine Hauser, Marion Ortner, Ines Lanzl, Christoph Schmaderer, Timo Grimmer; Dynamic retinal arterial and venous oscillations are changed in Alzheimer’s disease. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1256.
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© ARVO (1962-2015); The Authors (2016-present)
Vascular risk factors contribute to the development of Alzheimer's disease (AD). Retinal vessels are similar to cerebral vessels in their structure and function. We demonstrated previously that non-stimulated temporal retinal arterial and venous oscillations (pulsations, vasomotions) are changed in healthy volunteers with age, in primary open angle glaucoma and in diabetes mellitus type 1. Whether this dynamic retinal vessel behavior is altered in AD and related to clinical severity is investigated.
Three groups of participants were examined by Dynamic Vessel Analyzer (IMEDOS Systems, Jena, Germany): 11 patients, 76.2 (72.5 – 80.0) y.o. [median (1st. quartile – 3rd quartile)], with mild-to-moderate dementia due to probable AD fulfilling the standard diagnostic criteria (ADD); 20 patients, 69.2 (63.6 – 72.0) y.o. with mild cognitive impairment (MCI) due to AD, and 14 anamnestic healthy control subjects 67.1 (58.5 – 70.8) y.o. without cognitive impairment (HC). Oscillatory temporal changes of retinal vessel diameters were assessed during 40 s and were evaluated using mathematical signal analysis.
The relative to the vessel diameter magnitude of arterial oscillations was higher in ADD: 6.5% (6.1% – 7.5%) vs. HC: 4.4% (3.6% – 5.9%), p<0.01. Temporal shift between arterial and venous pulsations was different in ADD: 0.00 (-0.44 – 0.16) s vs. HC: 0.14 (0.01 – 0.69) s, p<0.05. Power spectra of the temporal curves differed between the groups especially within low frequency range: 0 – 0.2 Hz. In arteries at very low frequencies < 0.05 Hz HC oscillations, characterized by the normalized area under the power spectrum, prevailed over ADD and MCI oscillations. At moderate low frequencies (0.05 – 0.2 Hz) which correspond to lymphatic vessels’ pulsations, ADD and most MCI oscillations prevailed over HC oscillations.
Functional and morphological alterations in the retinal vessels in ADD are shown using a non-invasive in-vivo technique. The results are consistent with the amyloid clearance hypothesis of substrates being cleared from the brain along paravascular pathways due to vascular pulsation. The emphasized retinal arterial pulsation at moderate low frequencies in ADD and MCI group would be compatible with the view of compensatory overregulation in AD. Dynamic retinal vessel analysis could allow to reveal the etiology of AD and to contribute to its additional diagnostic characterization.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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