Real‐time fiber‐optic recording of acute‐ischemic‐stroke signatures

Abstract

We present an experimental framework and methodology for in vivo studies on rat stroke models that enable a real‐time fiber‐optic recording of stroke‐induced hydrogen peroxide and pH transients in ischemia‐affected brain areas. Arrays of reconnectable implantable fiber probes combined with advanced optogenetic fluorescent protein sensors are shown to enable a quantitative multisite time‐resolved study of oxidative‐stress and acidosis buildup dynamics as the key markers, correlates and possible drivers of ischemic stroke. The fiber probes designed for this work provide a wavelength‐multiplex forward‐propagation channel for a spatially localized, dual‐pathway excitation of genetically encoded fluorescence‐protein sensors along with a back‐propagation channel for the fluorescence return from optically driven fluorescence sensors. We show that the spectral analysis of the fiber‐probe‐collected fluorescence return provides means for a high‐fidelity autofluorescence background subtraction, thus enhancing the sensitivity of real‐time detection of stroke‐induced transients and significantly reducing measurement uncertainties in in vivo acute‐stroke studies as inherently statistical experiments operating with outcomes of multiply repeated measurements on large populations of individually variable animal stroke models.

The protective role of endothelial GLUT1 in ischemic stroke

“…Similarly, alkaline condition is demonstrated to favor GLUT1 transport activation (Gunnink et al., 2014 ). During stroke, deprivation of oxygen often causes decreased pH in brain parenchyma, which represents the acidity of environment and lowers GLUT1 activity (Pochechuev et al., 2022 ; Shah et al., 2015 ). To conclude, the increased adenosine/ATP ratio or decreased pH may suppress GLUT1 activity during stroke, which is likely to exacerbate the energy deficiency and lead to further damage.…”

Neurophotonics: a comprehensive review, current challenges and future trends

“…While different cells enter the photonic crystal cavity, the wavelength shifts of the resonant defect peak in the transmission spectra are calculated and used to detect different pathological conditions, such as GBM and Multiple sclerosis. Optical methodologies can also be valuable tools to measure and monitor transient disorder signatures against a highfloor noise background, as demonstrated in Pochechuev et al (2022) where arrays of fiber-optic probes were used to record, in real-time, stroke-induced hydrogen peroxide and pH transients when implanted in ischemia-affected brain areas. The platform is able to provide optical excitation and fluorescence read out from genetically encoded fluorescent protein sensors, that are used to quantify stroke growth dynamics.…”