Kumaran, S. K. | bioRxiv Science

bioRxiv2025

Cerebral blood flow in elastin haploinsufficient and 3xTg-AD mice

Artery structural properties and Alzheimers disease (AD) pathology are individually associated with impaired cerebrovascular function; however, the interaction of these factors is unclear. Furthermore, while elastin haploinsufficient (Eln+/-) mice are known to have impaired cerebrovascular function, sex differences for this effect have not been previously studied. To answer these questions, we crossed middle-aged and old Eln+/-mice with 3xTg-AD mice. We measured cerebral blood flow (CBF) using arterial spin labeling MRI at rest and during hypercapnia to calculate cerebrovascular reactivity (CVR). We also assessed neuroinflammation by microglia and astrocyte cell counts. We found that Eln+/- mice had lower resting blood flow rate in the cerebral cortex compared with Eln+/+ mice, but Eln+/- mice had an intact hypercapnic response, resulting in better CVR compared with Eln+/+ in hippocampus. Sex did not impact resting blood flow or CVR. 3xTg-AD mice had a lower resting CBF than non-AD mice, and there was an interaction between Eln genotype and AD mutations on CVR, such that Eln+/-x 3xTg-AD mice had the poorest hippocampal CVR of all groups. Glia cell counts were highly dependent on brain region, with Eln+/- having more microglia but fewer astrocytes, while 3xTg-AD having higher both microglia and astrocytes. While sex also impacted glial cell counts, we found no interactions between sex and Eln genotype. Our results demonstrate that elastin haploinsufficiency and AD mutations individually result in lower resting CBF, and the combination of these leads to impaired CVR. NEW & NOTEWORTHYThe findings of this study demonstrate that elastin haploinsufficiency leads to lower resting cerebral blood flow, but also greater cerebrovascular reactivity. However, elastin haploinsufficiency interacts with Alzheimers disease mutations to impair cerebrovascular reactivity. These results suggest that multiple insults, such as changes to the extracellular matrix combined with genetic risk factors, are needed to impact cerebrovascular reactivity.

physiology↗

bioRxiv2025

FishProx: Proximate conspecific interaction of Atlantic salmon (Salmo salar) for behavioural analysis through instance segmentation masks

In modern fish production and experimental facilities, camera installations are increasingly common for monitoring animal welfare. This opens up a new alley of autonomous tracking systems levering streamed data. However, the substantial amount of data necessitates condensation for human operators. In this paper, we present the out-of-the-box pipeline called FishProx that starts with the imagery of fish in tanks and ends in the calculation of welfare impacting factors through anomaly scores. The utilisation of the Segment Anything Model (SAM) is the basis for the identification of feeding behaviour and also (ab)normal behaviour through analysing snapshots of the fish tanks to infer metrics such as fish cohesion and cluster alignment, alongside the detection count. Our method employs automatic and robust algorithms for camera systems, making additional labelled data unnecessary, thereby saving energy and costs. Furthermore, automatic fish observation coupled with integrated analytical capabilities can lead to a sensible autonomous decision-making process. Lastly, by providing objective metrics, our approach might guide the enabling of automatic quantification of fish states, making comparative studies possible.

animal behavior and cognition↗