Multiparametric MRI for In Vivo Visualization of Renal Inflammation in Acute Kidney Injury

Area of Science:

• Biomedical imaging
• Nanotechnology
• Renal pathophysiology

Background:

• Renal ischemia-reperfusion injury (IRI) is a primary cause of acute kidney injury (AKI).
• Current diagnostic methods lack sensitivity and specificity for in vivo inflammation visualization, hindering early detection and intervention.
• Targeting inflammatory responses is crucial for understanding and managing AKI.

Purpose of the Study:

• To develop and evaluate an inflammation-targeting multiparametric MRI strategy for real-time visualization of AKI-associated inflammation.
• To assess the efficacy of a novel nanoprobe (NPs@PEG-PEP) in detecting inflammatory cell infiltration in IRI-induced AKI.
• To establish a platform for spatiotemporal mapping of AKI progression.

Main Methods:

• Development of a nanoprobe (NPs@PEG-PEP) functionalized with peptides targeting CD137, an immune activation receptor.
• Utilizing NaGdF4 nanoparticles for simultaneous dynamic contrast-enhanced MRI (DCE-MRI) and susceptibility-weighted imaging (SWI).
• In vivo evaluation of the nanoprobe's targeting ability, imaging signal persistence, and correlation with histopathological findings (H&E, CD11b).
• Assessment of the nanoprobe's biological safety through cytotoxicity assays, hemolysis tests, and histopathology.

Main Results:

• The NPs@PEG-PEP nanoprobe selectively targeted and accumulated in inflammatory cells within AKI-affected kidneys.
• Multiparametric MRI effectively captured differences in vascular perfusion and inflammatory cell infiltration.
• The inflammatory imaging signal demonstrated persistence for up to 18 hours and correlated well with histological evidence of inflammation.
• Biological safety evaluations confirmed the nanoprobe's biocompatibility.

Conclusions:

• An inflammation-targeting, multiparametric MRI platform using a CD137-targeting nanoprobe enables effective visualization of IRI-induced AKI.
• This approach facilitates spatiotemporal mapping of AKI progression, offering a promising strategy for early diagnosis and therapeutic monitoring.
• The developed nanoprobe demonstrates significant potential for improving the management of AKI.