Dataset Information

Semi-quantitative Assessment of Alzheimer's-like Pathology in Two Aged Polar Bears (Ursus maritimus).

ABSTRACT: Age-associated neurodegenerative changes, including amyloid β (Aβ) plaques, neurofibrillary tangles (NFTs), and amyloid angiopathy comparable to those seen in the brains of human patients with Alzheimer's disease (AD), have been reported in the brains of aged bears. However, the significance of these findings in bears is unclear due to the difficulty in assessing cognitive impairment and the lack of standardized approaches for the semiquantitative evaluation of Aβ plaques and NFTs. In this study, we evaluate the neuropathologic changes in archival brain tissue of 2 aged polar bears (Ursus maritimus, ages 28 and 37) using the National Institute of Aging-Alzheimer Association (NIA-AA) consensus guidelines for the neuropathologic assessment of Alzheimer's Disease (AD). Both bears had an Aβ (A) score of 3 of 3, Braak stage (B score) of 2 of 3, and neuritic plaque (C) score of 3 of 3. These findings are consistent with the neurodegenerative changes observed in brains of patients with AD. The application of NIA-AA consensus guidelines, as applied to the neuropathologic assessment of the aged bears in this report, demonstrates the use of standardized semiquantitative assessment systems for comparative, translational studies of aging in a vulnerable wildlife species.

SUBMITTER: Lucot KL

PROVIDER: S-EPMC9413527 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature

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Publications

Semi-quantitative Assessment of Alzheimer's-like Pathology in Two Aged Polar Bears (<i>Ursus maritimus</i>).

Lucot Katherine L KL Bukhari Syed A SA Webber Ebony D ED Bonham T Adam TA Darian-Smith Corinna C Montine Thomas J TJ Green Sherril L SL

Comparative medicine 20220726 4

Age-associated neurodegenerative changes, including amyloid β (Aβ) plaques, neurofibrillary tangles (NFTs), and amyloid angiopathy comparable to those seen in the brains of human patients with Alzheimer's disease (AD), have been reported in the brains of aged bears. However, the significance of these findings in bears is unclear due to the difficulty in assessing cognitive impairment and the lack of standardized approaches for the semiquantitative evaluation of Aβ plaques and NFTs. In this study ...[more]

PMID: 35882509

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Project description:We related straight-line body length and total body mass of polar bears to their body composition and associated storage energy using a dataset of dissected polar bears. Individual survival and reproduction can subsequently be predicted by estimating polar bear energy demands relative to their estimated energy stores. Abstract Climate warming is rapidly altering Arctic ecosystems. Polar bears (Ursus maritimus) need sea ice as a platform from which to hunt seals, but increased sea-ice loss is lengthening periods when bears are without access to primary hunting habitat. During periods of food scarcity, survival depends on the energy that a bear has stored in body reserves, termed storage energy, making this a key metric in predictive models assessing climate change impacts on polar bears. Here, we developed a body composition model for polar bears that estimates storage energy while accounting for changes in storage tissue composition. We used data of dissected polar bears (n = 31) to link routinely collected field measures of total body mass and straight-line body length to the body composition of individual bears, described in terms of structural mass and two storage compartments, adipose and muscle. We then estimated the masses of metabolizable proteins and lipids within these storage compartments, giving total storage energy. We tested this multi-storage model by using it to predict changes in the lipid stores from an independent dataset of wild polar bears (n = 36) that were recaptured 8–200 days later. Using length and mass measurements, our model successfully predicted direct measurements of lipid changes via isotopic dilutions (root mean squared error of 14.5 kg). Separating storage into two compartments, and allowing the molecular composition of storage to vary, provides new avenues for quantifying energy stores of individuals across their life cycle. The multi-storage body composition model thus provides a basis for further exploring energetic costs of physiological processes that contribute to individual survival and reproductive success. Given bioenergetic models are increasingly used as a tool to predict individual fitness and population dynamics, our approach for estimating individual energy stores could be applicable to a wide range of species.

Dataset Information

Semi-quantitative Assessment of Alzheimer's-like Pathology in Two Aged Polar Bears (Ursus maritimus).

Publications

Semi-quantitative Assessment of Alzheimer's-like Pathology in Two Aged Polar Bears (<i>Ursus maritimus</i>).

Similar Datasets

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