Authors: Konstantin Kotliar, Marion Ortner, Mahmut Bilirer, Christine Hauser, Christoph Schmaderer, Timo Grimmer
Published: 2020-12-07
DOI: 10.1002/alz.043549
Source: Full article
AbstractBackgroundVascular risk factors contribute to the development of Alzheimer's disease (AD). We demonstrated previously that functional retinal arterial reaction to flicker stimulation and retinal arterial vasomotion are altered in mild‐to‐moderate AD dementia. The spatial structure of the retinal artery blood column measured along the vessel axis is termed longitudinal arterial profile (LAP). It reflects configuration of internal retinal arterial wall and can be assessed with modern in‐vivo retinal imaging. Whether LAP is altered in retinal arteries of AD patients and whether it changes during vascular constriction/dilation is investigated.Method13 patients, 72.7(67.1 – 78,6) y.o. [median(1st quartile – 3rd quartile)], with mild‐to‐moderate dementia due to probable AD fulfilling the standard diagnostic criteria (ADD); and 15 anamnestic healthy control subjects 69.2(60.9 – 71.1) y.o. without subjective/objective cognitive impairment (HC) were examined with Dynamic Vessel Analyzer (IMEDOS Systems, Jena). In retinal arterial segments of 1280 µm in length vessel diameters were measured with a spatial resolution of 10µm in order to obtain LAP at different stages of arterial reaction to flicker. Differences in amplitude and frequency of spatial vessel diameter changes were analysed using Fast Fourier Transformation.ResultThe magnitude of spatial arterial diameter changes was higher in HC than in ADD during all stages of arterial response, p<0.01. At baseline it amounted to 40(32 – 54) µm in HC and to 24(20 – 29) µm in AD. Compared to the arteries of HC power spectra of LAP in AD patients showed pronounced waves with a period of ∼200 µm during baseline and vasodilation (parameter: area under the power spectra at certain frequency range), and pronounced waves with a period of ∼100 µm during vasodilation and relaxation (p <0.05).ConclusionDynamic functional alterations of retinal arteries in AD dementia are shown using a non‐invasive in‐vivo technique. Retinal arteries of AD patients change their internal microstructure which is especially emphasized during vasodilation. Further research of retinal vascular function in AD dementia should reveal the reason for the reported structural vascular alterations. Since dynamic retinal vessel analysis provides a direct non‐invasive assessment of microcirculatory damage, it could allow for additional diagnostic characterization of AD.