Photoacoustic imaging assessment of acute kidney injury associated with experimental necrotizing enterocolitis

Abstract

BackgroundNecrotizing enterocolitis (NEC) is a devastating gastrointestinal condition increasingly recognized to cause systemic complications, including acute kidney injury (AKI). However, the underlying mechanisms and variations in renal impairment remain largely unknown, and there is a lack of non-invasive imaging methods for detecting early kidney injury. MethodsWe evaluated kidney injury through a multimodal approach, using a neonatal rat model of experimental NEC. Plasma and renal tissue were analyzed for pro-inflammatory cytokines (TNF-, IL-6, IL-1{beta}) by ELISA. Histological analysis and immunofluorescence staining were used to identify renal abnormalities and expressions of KIM-1 and NGAL. Photoacoustic imaging (PAI) was used to assess renal oxygenation and total hemoglobin as functional imaging biomarkers of kidney injury. ResultsNEC pups showed significant elevations of systemic and renal cytokines, as well as increased expression of KIM-1, NGAL and CD31 in proximal tubules of the kidney. Histological examination further confirms renal injury in the NEC cohort. PAI demonstrated reduction in renal oxygen saturation, offering non-invasive assessment of physiological kidney damage. ConclusionThis study characterizes AKI associated with NEC as an inflammatory and hypoxic response in the neonatal rat NEC model and introduces PAI as a promising imaging modality for non-invasive evaluation of renal injury in NEC.