Non-Invasive Imaging Modalities for Immune Monitoring of Vascularized Composite Allografts Using a Translational Large Animal Model

G. Furtmüller,¹ N. Crane,² R. Luthra,² E. Swanson,¹ H.-T. Cheng,¹ B. Oh,¹ M. Fryer,¹ E. Elster,² W. Lee,¹ G. Brandacher.¹

¹Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, MD
²Department of Regenerative Medicine, Naval Medical Research Center, Silver Spring, MD.

Meeting: 2015 American Transplant Congress

Abstract number: C253

Keywords: Non-invasive diagnosis, Rejection

Session Information

Session Name: Poster Session C: Translational Biomarkers and Immune Monitoring

Session Type: Poster Session

Date: Monday, May 4, 2015

Session Time: 5:30pm-6:30pm

Presentation Time: 5:30pm-6:30pm

Location: Exhibit Hall E

Purpose: To evaluate imaging modalities such as 3CCD and infrared (IR) technology as a means of non-invasive monitoring of graft acceptance and rejection in the setting of VCA. Methods: Heterotopic hind limb transplantation in a swine model was performed across a full SLA-mismatched barrier. Animals were assigned to two groups of untreated control and standard immunosuppression with Tacrolimus with a dose of 0.1 mg/kg and trough levels of 15-20 ng/ml. On the day of transplantation, the donor, the graft as well as the recipient were imaged with 3CCD and IR cameras. Follow-up imaging was performed on postoperative days (POD) 2, 4, 6, 8, 10, 30 and 60. Paralleling the imaging at these time points, we also performed invasive sampling of full thickness graft and recipient skin for histopathology and Raman spectroscopic analysis.

Results: Untreated controls rejected the graft as defined by epidermolysis of the skin component within 5 days post transplantation (n=3). Animals receiving standard immunosuppression maintained their allograft without any clinical signs of rejection (n=3). Both 3CCD and IR imaging show no significant changes from baseline values indicating vital grafts at POD2 in both treated and untreated animals. However, analysis of data collected on POD4 reveals a large decrease (12-32%) in 3CCD intensity values compared to POD 2 intra-individually as well as across treatment groups. Host tissue surrounding the graft and the underlying donor tissue, demonstrates an increase (24-43%) in infrared intensity values compared to both the graft and adjacent host tissue. Raman spectra signify molecular changes in the graft tissue as early as POD2, evidenced by loss of lipid content and increased collagen content. Lipid loss in graft tissue was not as evident in animals with full immunosuppression. Conclusion: Preliminary data obtained by this study shows that non-invasive imaging modalities detect subtle physical property changes in tissue homeostasis during an ongoing immune response after vascularized composite allotransplantation. Early changes in 3CCD and IR imaging intensity values for both the donor and recipient tissues portend graft rejection.

To cite this abstract in AMA style:

Furtmüller G, Crane N, Luthra R, Swanson E, Cheng H-T, Oh B, Fryer M, Elster E, Lee W, Brandacher G. Non-Invasive Imaging Modalities for Immune Monitoring of Vascularized Composite Allografts Using a Translational Large Animal Model [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/non-invasive-imaging-modalities-for-immune-monitoring-of-vascularized-composite-allografts-using-a-translational-large-animal-model/. Accessed May 18, 2025.

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