Longitudinal, Non-invasive Live Near-Infrared Fluorescence Imaging of Acute Vascularized Composite Allograft Rejection Validated by Ex Vivo ¹⁹F Magnetic Resonance Imaging and Histopathology.
4 affiliations
- 1Nanomedicine Manufacturing Laboratory, Graduate School of Pharmaceutical Sciences and School of Pharmacy, Duquesne University, Pittsburgh, PA, USA.
- 2Wake Forest Institute for Regenerative Medicine, Advocate Health - Atrium Wake Forest Baptist Medical Center, Winston-Salem, NC, USA.
- 3Advanced Imaging Center, University of Pittsburgh, Pittsburgh, PA, USA.
- 4Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA.
Abstract
Acute rejection remains a major cause of graft attrition in vascularized composite allotransplantation (VCA). Clinical assessment and superficial biopsy may fail to detect early or spatially heterogeneous inflammatory infiltration, particularly within deeper graft compartments. Because macrophages are among the earliest mediators of alloimmune activation, they represent an attractive target for noninvasive immune surveillance of skin-bearing grafts. We evaluated longitudinal near-infrared fluorescence (NIRF) imaging of macrophage infiltration using a perfluoro-15-crown-5 ether nanoemulsion (PCE-NE) labeled with a near-infrared fluorophore in a rat hindlimb transplantation model and a radial forearm flap model in non-human primates (NHPs). Single- and dual-dose administration strategies enabled serial visualization of macrophage recruitment and improved detection of evolving inflammatory responses during acute rejection. To capture the spatial heterogeneity of rejection, a multi-sampled region-of-interest analysis framework was developed for quantitative mapping of NIRF signal across donor and recipient tissues in rats and throughout transplanted flap regions in NHPs. To validate in vivo imaging findings, grafts were analyzed ex vivo using fluorine-19 (¹⁹F) magnetic resonance imaging, histopathology, and CD68 immunofluorescence. NIRF signal identified rejecting graft regions and demonstrated spatial patterns of inflammatory infiltration that corresponded to compartment-specific ¹⁹F MRI signal localization in ex vivo imaging. Imaging findings corresponded with Banff rejection grade and CD68-positive macrophage accumulation across Grade I-IV rejection. Importantly, increased NIRF and ¹⁹F MRI signals were detected during early Grade I-II rejection, when clinical manifestations remained limited. These findings establish a translational multimodal imaging strategy for longitudinal, noninvasive monitoring of acute VCA rejection and demonstrate concordance between in vivo NIRF imaging, ex vivo ¹⁹F MRI, histopathology, and immunofluorescence across rodent and non-human primate models.
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BibTeX
@article{janjic2026longitudinal,
title = {{Longitudinal, Non-invasive Live Near-Infrared Fluorescence Imaging of Acute Vascularized Composite Allograft Rejection Validated by Ex Vivo ¹⁹F Magnetic Resonance Imaging and Histopathology.}},
author = {Jelena M Janjic and Yalcin Kulahci and Fatih Zor and Sanjida Ahmed Srishti and Riddhi Vichare and Lesley M Foley and Zeynep Demir and Bedreddin Sazoğlu and Fatma Nurefsan Selek and Omer Dirican and Vidya Surti and Stefan Stratimirovic and Caitlin Crelli and Rebecca McCallin and Michele Herneisey and Huseyin Karagoz and T Kevin Hitchens and Vijay S Gorantla},
journal = {Nanotheranostics},
year = {2026},
month = oct,
doi = {10.7150/ntno.139245},
url = {https://europepmc.org/article/MED/42910404},
note = {CC BY},
}
RIS
TY - JOUR
TI - Longitudinal, Non-invasive Live Near-Infrared Fluorescence Imaging of Acute Vascularized Composite Allograft Rejection Validated by Ex Vivo ¹⁹F Magnetic Resonance Imaging and Histopathology.
AU - Jelena M Janjic
AU - Yalcin Kulahci
AU - Fatih Zor
AU - Sanjida Ahmed Srishti
AU - Riddhi Vichare
AU - Lesley M Foley
AU - Zeynep Demir
AU - Bedreddin Sazoğlu
AU - Fatma Nurefsan Selek
AU - Omer Dirican
AU - Vidya Surti
AU - Stefan Stratimirovic
AU - Caitlin Crelli
AU - Rebecca McCallin
AU - Michele Herneisey
AU - Huseyin Karagoz
AU - T Kevin Hitchens
AU - Vijay S Gorantla
PY - 2026
DA - 2026/10/09
JO - Nanotheranostics
DO - 10.7150/ntno.139245
UR - https://europepmc.org/article/MED/42910404
AB - Acute rejection remains a major cause of graft attrition in vascularized composite allotransplantation (VCA). Clinical assessment and superficial biopsy may fail to detect early or spatially heterogeneous inflammatory infiltration, particularly within deeper graft compartments. Because macrophages are among the earliest mediators of alloimmune activation, they represent an attractive target for noninvasive immune surveillance of skin-bearing grafts. We evaluated longitudinal near-infrared fluorescence (NIRF) imaging of macrophage infiltration using a perfluoro-15-crown-5 ether nanoemulsion (PCE-NE) labeled with a near-infrared fluorophore in a rat hindlimb transplantation model and a radial forearm flap model in non-human primates (NHPs). Single- and dual-dose administration strategies enabled serial visualization of macrophage recruitment and improved detection of evolving inflammatory responses during acute rejection. To capture the spatial heterogeneity of rejection, a multi-sampled region-of-interest analysis framework was developed for quantitative mapping of NIRF signal across donor and recipient tissues in rats and throughout transplanted flap regions in NHPs. To validate in vivo imaging findings, grafts were analyzed ex vivo using fluorine-19 (¹⁹F) magnetic resonance imaging, histopathology, and CD68 immunofluorescence. NIRF signal identified rejecting graft regions and demonstrated spatial patterns of inflammatory infiltration that corresponded to compartment-specific ¹⁹F MRI signal localization in ex vivo imaging. Imaging findings corresponded with Banff rejection grade and CD68-positive macrophage accumulation across Grade I-IV rejection. Importantly, increased NIRF and ¹⁹F MRI signals were detected during early Grade I-II rejection, when clinical manifestations remained limited. These findings establish a translational multimodal imaging strategy for longitudinal, noninvasive monitoring of acute VCA rejection and demonstrate concordance between in vivo NIRF imaging, ex vivo ¹⁹F MRI, histopathology, and immunofluorescence across rodent and non-human primate models.
SN - 2206-7418
ER -