Alzheimer’s disease is a devastating condition that affects millions of families worldwide, changes loved ones beyond recognition and presents significant care and financial challenges. For years, scientists have been searching for reliable biomarkers for early diagnosis and the development of effective treatments. Recent research has uncovered a fascinating discovery: the telltale signs of Alzheimer’s, such as amyloid-beta (Aβ) plaques and phosphorylated tau clusters, can begin to accumulate in the brain as early as two decades before symptoms appear.
The EMIF-AD project: twins shed light on Alzheimer’s disease
At Amsterdam UMC, an innovative study called the EMIF-AD project has been following a unique group of participants every two years since 2015: cognitively normal identical twins. This study uses several advanced techniques to track neurological and retinal changes over time, including:
- Neuropsychological assessments
- PET and MRI brain scans.
- CSF and blood biomarker analysis.
- Proteomics
- Ophthalmic examination
Findings in the retina
A recent study led by Katie Curro, a doctoral student at Amsterdam UMC, analyzed Aβ PET results from these twin participants over a four-year period. The findings, published in the Journal of Investigative Ophthalmology and Visual Sciences (IOVS), categorized the participants into three groups:
- Healthy controls
- Converters (initially negative, then positive)
- Consistently positive
Using an advanced imaging technology called Optical Coherence Tomography Angiography (OCT-A), Curro examined blood vessels in the retina, particularly in the macula and the area around the optic nerve. Their findings were intriguing:
- The consistently positive group showed significantly higher vascular density in both the inner and outer regions of the macula compared with the other groups.
- Although no major changes were observed around the optic nerve over two years, the macula in the consistently positive group showed an increasing trend in vessel density.
What this means for Alzheimer’s research
These results suggest that different parts of the retina may respond differently to the accumulation of Aβ in the brain. This discovery opens up exciting new possibilities for early Alzheimer’s detection using simple, non-invasive eye examinations.
Looking ahead: The future of Alzheimer’s research
Curro and her team at Amsterdam UMC are excited to continue this groundbreaking research with additional ocular imaging devices. They plan to track these retinal changes alongside tau data, another important protein implicated in Alzheimer’s disease. This comprehensive approach will help us better understand how neurodegeneration in the retina is linked to Alzheimer’s progression in the brain. By discovering these early warning signs, researchers hope to pave the way for earlier interventions and more effective treatments for Alzheimer’s disease, offering hope to millions of families affected by this challenging condition.