Abstract
Introduction: Preeclampsia is a hypertensive disorder of pregnancy associated with placental dysfunction. Optoacoustic imaging enables non-invasive, real-time assessment of placental oxygen saturation. This study aimed to evaluate placental oxygenation and its response to hypoxia in the STOX1A mouse model of preeclampsia.
Methods: Two groups were studied: STOX1A pregnancies (wild-type females crossed with transgenic STOX1A males) and controls (wild-type crosses). Blood pressure and urinary albumin-to-creatinine ratio were monitored during gestation. Placental oxygen saturation was assessed by multispectral optoacoustic imaging between embryonic days 15.5 and 17.5 under normoxia and hypoxia. Delta oxygen saturation and desaturation kinetics were analyzed using sigmoid curve fitting.
Results: Thirty-one placentas from seventeen control pregnancies and twenty-nine placentas from twenty STOX1A pregnancies were analyzed. The STOX1A group showed increased blood pressure and albuminuria compared to controls (mean systolic blood pressure change at embryonic day 17.5: +21.2 ± 11 mmHg versus -8.4 ± 3.7 mmHg, p = 0.006; albumin-to-creatinine ratio fold-change: 3.91 [2.52-17.14] versus 0.86 [0.43-2.49], p = 0.033). Placental baseline oxygen saturation was similar between groups (70.1 ± 5.3 percent versus 70.0 ± 6.9 percent, p = 0.96). No significant differences were observed in delta oxygen saturation (17.0 ± 6.9 percent versus 16.1 ± 7.1 percent, p = 0.61) or desaturation rate (8.6 ± 6.0 versus 7.9 ± 6.1, p = 0.43) during hypoxia.
Discussion: Despite a confirmed preeclamptic phenotype, placental oxygenation and adaptation to maternal hypoxia were preserved in the STOX1A model, suggesting maintained placental resilience in late gestation.
Keywords: Mouse model; Optoacoustic imaging; Placental oxygenation; Preeclampsia.