Sita N Shah, Maria-Eleni Dounavi, Paresh A Malhotra, Brian Lawlor, Lorina Naci, Ivan Koychev, Craig W Ritchie, Karen Ritchie, John T O’Brien

Brain Communications (2024)

DOI: https://doi.org/10.1093/braincomms/fcae046

Summary

The Thalamus is an area of the brain involved with several processes, such as cognitive function and sleep, and has been shown to be affected in the dementia disease process. This study sought to investigate volumetric differences in the thalamus and its sub-regions in middle-aged participants in the PREVENT-Dementia study with respect to dementia family history and the apolipoprotein e4 (APOE) allele carriership and its relationship with cognitive function.

No volumetric differences were found in the thalamus and its sub-regions between groups. A larger volume of the medial thalamus was associated with faster processing speeds in individuals without dementia family history. However, larger volumes of the thalamus and posterior thalamus was associated with worse performance on  immediate recall ability in APOE4 allele carriers. The findings could highlight an initial dysregulation in the disease process, but further study is needed to assess for changes in the thalamus over time.

Samuel Gibbon, Graciela Muniz-Terrera, Fabian S. L. Yii, Charlene Hamid, Simon Cox, Ian J. C. Maccormick, Andrew J. Tatham, Craig Ritchie, Emanuele Trucco, Baljean Dhillon, Thomas J. MacGillivray

Neuro-ophthalmology (2024)

DOI: https://doi.org/10.1167/tvst.13.5.20

Summary

In dementia, nerve cells in the brain called neurons stop functioning properly, lose connections with other neurons, and eventually die prematurely. The eye is a window into the human body where we can easily study the nerves of the retina which might reflect the health and condition of similar, but less accessible, tissues in the brain.  In this paper we explain how we have developed software that quantifies the appearance of the optic nerve head in fundus images as a marker of loss of nerve tissue that makes this feature appear lighter and paler. Our technique could potentially become a straightforward test to monitor for change over time and spot people most at risk of developing dementia later in life. In turn, this could help target the recruitment of clinical trials of new treatments at the most suitable individuals.

Elijah Mak, Maria-Eleni Dounavi, Grégory Operto, Elina T Ziukelis, Peter Simon Jones, Audrey Low, Peter Swann, Coco Newton, Graciela Muniz Terrera, Paresh Malhotra, Ivan Koychev, Carles Falcon, Clare Mackay, Brian Lawlor, Lorina Naci, Katie Wells, Craig Ritchie, Karen Ritchie, Li Su, Juan Domingo Gispert, John T O’Brien.

Brain Communications (2024)

DOI: https://doi.org/10.1016/j.numecd.2023.07.020

Summary

The APOE ε4 gene is the strongest genetic risk factor for the most common form of Alzheimer’s disease, however, exactly how APOE4 contributes to Alzheimer’s is not fully clear. This was addressed in a collaboration between the PREVENT Dementia programme and the ALFA (ALzheimer’s and FAmilies) cohort in Barcelona.

Using an advanced brain imaging technique called Neurite Orientation Dispersion and Density Imaging (NODDI) in nearly 2,000 cognitively normal adults, the research teams found APOE4 worsened age-related loss of complexity of brain cell connections. These effects were most pronounced in areas of the brain vulnerable to Alzheimer’s disease and involved in memory function.

The findings, suggest APOE4 may promote the development of Alzheimer’s disease by hastening disruptive aging processes in neuron connectivity, especially in memory-critical areas.

Maria-Eleni Dounavi , Elijah Mak, Peter Swann, Audrey Low, Graciela Muniz-Terrera, Anna McKeever,
Marianna Pope, Guy B Williams, Katie Wells, Brian Lawlor, Lorina Naci, Paresh Malhotra, Clare Mackay, Ivan Koychev, Karen Ritchie, Li Su, Craig W Ritchie and John T O’Brien.

Journal of Cerebral Blood flow & Metabolism (2023)

DOI: https://doi.org/10.1177/0271678X231173587

Summary

Timely delivery of oxygen and nutrients to the brain via the bloodstream is crucial for the maintenance of brain health. Using a brain imaging technique called arterial spin labelling (ASL) we can measure the delivery of blood to the brain tissue to quantify cerebral blood flow (CBF). In the present study we examined differences in blood flow between people who carry at least one copy of the apolipoprotein ε4 (APOE4) gene (potential higher risk for future Alzheimer’s disease) and those who do not carry any copy of APOE4. We also examined the relationship between different sizes and shapes of red blood cells and cerebral blood flow.

APOE4 carriers demonstrated an unexpected pattern of higher cerebral blood flow in their brain. We have also found that the relationship between CBF and size and shape of red blood cells is different between APOE4 carriers and non-carriers, especially in areas that are far from the arteries supplying blood to the brain.