Levels of Organochlorine Pesticides Are Associated with Amyloid Aggregation in Apex Avian Brains

Abstract

Organochlorine (OC) pesticides pose a significant environmental risk to wildlife and humans and have been associated with Alzheimer's disease (AD). This study aims to spectroscopically analyze brains from free-flying birds and link the results to OC exposure and consequent amyloid aggregation. As long-lived apex predators, predatory birds represent a sentinel species similar to humans. Therefore, the results have implications for both species and may also add to our understanding of the role OC pesticides play in the development of AD. Brains of wild Sparrowhawks were analyzed using ATR-FTIR and Raman spectroscopy and Congo red staining; results were correlated with OC pesticide concentrations in livers. Effects of OC exposure were sex- and age-dependent and associated alterations were seen in lipids and protein secondary structure. A shift from α-helix to β-sheet conformation of proteins indicated that concentrations of OC pesticides >7.18 μg/g may lead to cerebral amyloid aggregation.

Raman Imaging Reveals Accumulation of Hemoproteins in Plaques from Alzheimer’s Diseased Tissues

“…A transition of the amide I peak from 1662 cm –1 (black line, normal mice tissue) to 1630 cm –1 (red line, diseased tissue) is seen. The shift corresponds to the expected accumulation of peptides and proteins organized in parallel β-sheet type structures . In AD, this accumulation is related to the aggregation of Aβ .…”

“…The shift corresponds to the expected accumulation of peptides and proteins organized in parallel β-sheet type structures. 28 In AD, this accumulation is related to the aggregation of Aβ. 29 The map obtained by infrared microscopy (Figure 1B) shows the intensity distribution of the 1630 cm −1 signal, revealing the strong concentration of parallel β-sheet type structures in the core of the plaque (bright color in the map) and its absence in the surroundings (dark color).…”

The value of monitoring wildlife roadkill

“…cardiff.ac.uk/otter-project), has through post-mortems of collected otters found high levels of flame retardants in otter tissues (Pountney et al 2015), but also declining levels of lead over time, following tighter environmental regulations (Chadwick et al 2011). A similar long-term carcass collection project that receives roadkill birds of prey, the 'Predatory Bird Monitoring Scheme' (https://pbms.ceh.ac.uk/), has found contaminants such as organochloride insecticides (Heys et al 2017), flame retardants (Crosse et al 2013), and anticoagulant rodenticides (Walker et al 2008) in raptors, sampling that would not have been possible (due to legislative protection) without the collection of roadkill.…”

“…Roadkill records can be used to 'fill in the blanks' on species distribution maps when the live animal is rarely or infrequently seen, as well as for monitoring the spread of species that are both recolonising and invading (Caley et al 2015;Calenge et al 2015;Croose 2016), and this species tracking could also include monitoring of changing animal behavioural patterns (Haigh 2012;Madden and Perkins 2017;Sovada et al 1998). Finally, collecting biological samples from roadkill carcasses can provide increasing ecological and geographic resolution for contaminant studies (Chadwick et al 2013;Heys et al 2017;Smallbone et al 2017).…”

Aluminium foil as an alternative substrate for the spectroscopic interrogation of endometrial cancer

“…ATR‐FTIR uses an internal reflection element (IRE) with a high refractive index to direct the beam to the sample; an evanescent wave is created, penetrating the sample by a few microns in order to derive its chemical information . A commonly used substrate for ATR‐FTIR measurements is the low‐E slide that has been effectively used in numerous biological studies in the past . Therefore, we compared our results from the low‐E slides with those from Al foil slides to assess the performance of the latter with regard to the diagnostic accuracy.…”