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Impaired retinal microcirculation in patients with Alzheimer's disease

Hong Jiang1,2, Yi Liu1,3, Yantao Wei1,4

  • 1Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States of America.

Plos One
|February 3, 2018
PubMed

Insights

Retinal blood flow is reduced in patients with mild cognitive impairment and Alzheimer's disease, alongside thinning of the inner retinal layers. This indicates neurovascular and hemodynamic system impairment contributing to disease progression.

Area of Science:

  • Ophthalmology
  • Neurology
  • Medical Imaging

Background:

  • Mild cognitive impairment (MCI) and Alzheimer's disease (AD) are neurodegenerative conditions impacting cognitive function.
  • The neurovascular-hemodynamic system, including retinal blood flow, may be affected in these diseases.
  • Previous research suggests potential alterations in ocular blood flow in neurodegenerative disorders.

Purpose of the Study:

  • To quantify retinal blood flow rate (BFR) and blood flow velocity (BFV) in pre-capillary arterioles and post-capillary venules.
  • To compare these hemodynamic parameters between patients with AD, MCI, and cognitively normal (CN) controls.
  • To assess the relationship between retinal blood flow, inner retinal layer thickness, and cognitive status.

Main Methods:

  • Recruited 40 patients (20 AD, 20 MCI) and 21 CN controls, matched for age.
  • Utilized a retinal function imager (RFI) to measure macular BFR and BFV in arterioles and venules.
  • Measured ganglion cell-inner plexiform layer (GCIPL) thickness using Zeiss Cirrus optical coherence tomography.

Main Results:

  • Significantly lower macular BFRs were observed in AD patients compared to MCI and CN groups (P < 0.05).
  • MCI patients exhibited lower BFRs than CN controls in both arterioles and venules (P < 0.05).
  • Arteriolar BFV was significantly lower in AD patients than in CN controls (P = 0.01), and GCIPL thickness was reduced in both AD and MCI groups compared to CN.

Conclusions:

  • Reduced retinal blood flow in both arterioles and venules, along with GCIPL thinning, is evident in AD and MCI patients.
  • These findings suggest impairment of the neurovascular-hemodynamic system in the progression of cognitive decline.
  • Retinal blood flow measurements may serve as a potential biomarker for neurodegenerative diseases.

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