Elderly cats have a bit of a reputation. Some enjoy lazing in the sun; others grow irritable and disoriented, yowling at all hours of the night (much to the chagrin of their owners). Per a new study, this erratic behavior could be due to amyloid-beta plaque buildup in the feline brain, similar to that exhibited in adults with certain types of dementia. Read on for a summary of the study, published on August 11 in the European Journal of Neuroscience, and its implications for humans with Alzheimer’s disease.
Elderly Cats, Amyloid, & Alzheimer’s Disease
The study refers to Feline Cognitive Dysfunction Syndrome (CDS) as a “naturally occurring model of Alzheimer’s disease” (AD). The syndrome is characterized by disruptive behaviors, including “increased vocalization, altered social interactions, sleep–wake cycle, disorientation, and house-soiling.” Unfortunately, its mechanisms have been poorly understood in the past, making treatment challenging.
What causes this behavior in elderly cats? The study posits that amyloid-beta plaque buildup is the direct cause of numerous issues within the feline brain, including hyperactivation of two supportive brain cell types: microglia and astrocytes. This hyperactivation seems to cause the cells to attack the synapses that connect neurons.
Amyloid Pathology in Feline CDS
The study was led by Robert McGeachan, a veterinarian at the University of Edinburgh. He based the research on earlier studies that had already identified amyloid beta in the brains of cats, but were unable to confirm whether the buildup itself was disrupting brain function. The researchers wrote: “Is amyloid-beta pathology simply an age-related incidental finding, or does it actively contribute to neurodegeneration and the signs observed in feline CDS?”
McGeachan’s team looked at the postmortem brains of 7 young cats and 18 older cats. Eight of the older cats had shown behavioral changes consistent with CDS for at least three months prior to death.
To evaluate the brains, the team first dissected the tissue into anatomical brain regions. Then, they used fluorescent markers specifically designed to detect and cling to amyloid beta. They found that the brains of the elderly cats — with or without CDS — had more amyloid-beta than the brains of younger cats. These plaques also tended to accumulate around synapses, the junctions where neurons connect with other neurons, engulfing these key zones and impairing their function. The researchers wrote that this finding was “in line with previous findings in AD brains and rodent models of amyloid pathology.”
Elderly Cats: The Next Frontier of AD Research?
As mentioned above, the elderly cats also showed significantly overactive microglia, which are immune cells that regulate inflammation. They also showed signs of overactive astrocytes, which are glial cells that perform key metabolic, structural, and neuroprotective tasks. Together, the microglia and astrocytes dismantled the synapses, disrupting neural function the same way they do in humans with AD.
_____
Although only a small number of cats were studied, the results could have a twofold impact. First, they could help experts understand and treat feline dementia. Second, by allowing researchers to closely examine AD-associated hallmarks within cat brains, they could provide fresh insights into human dementia. It’s a win-win that could improve the quality of life of both species.
Did you enjoy this blog post? Check out our other blog posts as well as related topics on our Webinar page.
QPS is a GLP- and GCP-compliant contract research organization (CRO) delivering the highest grade of discovery, preclinical, and clinical drug research development services. Since 1995, it has grown from a tiny bioanalysis shop to a full-service CRO with 1,200+ employees in the US, Europe, Asia, India and Australia. Today, QPS offers expanded pharmaceutical contract R&D services with special expertise in pharmacology, DMPK, toxicology, bioanalysis, translational medicine, cell therapy (including PBMCs, leukopaks and cell therapy products), clinical trial units and clinical research services. An award-winning leader focused on bioanalytics and clinical trials, QPS is known for proven quality standards, technical expertise, a flexible approach to research, client satisfaction and turnkey laboratories and facilities. Through continual enhancements in capacities and resources, QPS stands tall in its commitment to delivering superior quality, skilled performance and trusted service to its valued customers. For more information, visit www.qps.com or email info@qps.com.
