Year: 2026
Type: preprint
Abstract: Background Understanding fetal brain responses to hypoxiaischemia is of growing interest, as it remains unclear to what extent these responses differ from those of newborns and whether developmental adaptations during gestation contribute to such differences. Materials and methods Using a combination of broadband near-infrared spectroscopy (bNIRS) and diffuse correlation spectroscopy (DCS), we measured brain microvascular oxygen saturation (StO 2 ), total hemoglobin concentration (THC), relative cerebral blood flow (rCBF), and the oxidation state of cytochrome c oxidase (oxCCO) during an acute ischemic challenge in the brains of five rabbit fetuses in utero. Simultaneous measurements were acquired from four control fetuses located in the contralateral uterine horn. Results During the hypoxia-ischemia phase, we observed a rapid reduction of CBF (47% ± 29%) and StO 2 , (from 64.7% ± 1.5% at baseline to 40.6% ± 2.0%) together with an increase of oxCCO (3.7μM ± 0.5μM). Conclusion The simultaneous increase in oxCCO and decrease in rCBF and StO 2 during hypoxia-ischemia reveals a cerebral response pattern that differs from that commonly reported in the newborn brain. These findings support the hypothesis that unique developmental adaptations influence fetal cerebral metabolism during hypoxic-ischemic stress.
Institutions: Institute of Photonic Sciences, Barcelona Institute of Science and Technology, Hospital Sant Joan de Déu Barcelona, Universitat de Barcelona, University of Cambridge, University College London, Consorci Institut D'Investigacions Biomediques August Pi I Sunyer, Institució Catalana de Recerca i Estudis Avançats
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7221523433