Ageing changes in cat brains demonstrated by β-amyloid and AT8-immunoreactive phosphorylated tau deposits

Abstract

The life expectancy of domestic pet cats is increasing, along with the occurrence of geriatric-onset behavioural problems, such as cognitive dysfunction syndrome (CDS). While the cause of CDS is unclear, it has been suggested that it may result from age-related neurodegeneration. In aged and in particular senile human beings, histopathological changes may include the extracellular accumulation of plaque-like deposits of beta-amyloid (Abeta) protein and the intracellular accumulation of an abnormally hyperphosphorylated form of the microtubule-associated protein, tau. In severe cases, the latter may form into neurofibrillary tangles. Brain material was assessed from 19 cats, aged from 16 weeks to 14 years; 17 of which had clinical signs of neurological dysfunction. Immunohistochemical methods were used to detect Abeta and its intracellular precursor protein (amyloid precursor protein (APP)) and hyperphosphorylated-tau. APP was constitutively expressed, with diffuse staining of neurons and blood vessels being detected in all cats. More intense staining and diffuse extracellular Abeta staining deposits were found within the deep cortical areas of the anterior- and occasionally mid-cerebrum of seven cats, all of which were over 10 years of age. Neurons staining intensely positive for AT8-immunoreactivity were seen in two cats, aged 11 and 13 years. However, no mature neurofibrillary tangles were detected. This study demonstrated that extracellular Abeta accumulation and AT8-immunoreactivity within neurons are age-related phenomena in cats, and that they can occur concurrently. There are similarities between these changes and those observed in the brains of aged people and other old mammals.

Aging in the Canine and Feline Brain

“…66 To our knowledge, there are few reports of the link between behavioral dysfunction and the extent of Aβ disorder as reported in dogs. Although cats that show signs of behavioral dysfunction tend to also have Aβ plaques, 100 the severity of behavioral changes does not seem to correlate well with the extent of Aβ disorder. 66 …”

“…66 Tau phosphorylation is also more frequently associated with the presence of seizures in aging cats. 100 …”

Transmission of Tau Pathology from Human to Rodent Brain: How to Humanise Animal Models for Alzheimer’s Disease Research

“…Most affected neurons have been identified as pyramidal neurons of the hippocampus and entorhinal cortex [42][43][44][45][46][47][48][49][50][51][52]. These findings suggest a selective vulnerability of this brain region and anatomical conservation of the disease progression in various animal species.…”

Atlarda Yaşla İlgili Beyinde Oluşan Histopatolojik ve İmmunohistokimyasal Değişiklikler

“…Aging brains undergo many changes and these are described in detail in human beings [3][4][5] and in many animal species [6][7][8][9][10] . Neuroaxonal dystrophy, calcification and inflammation are the common changes in the aging brains, pathogenesis and functional consequences of these changes are not fully understood [11][12][13][14] .…”