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Ex Vivo Normothermic Limb Perfusion Upregulates Cellular Inflammatory and Stress Response Pathways Conferring Protection Against Compartment Syndrome
Abigail Meyers, Jesse Zhan, Mazen Al-Malak, Jacob Lammers, Brian Figueroa, Ying Ku, Lianne Mulvihill, Antonio Rampazzo, Bahar Bassiri Gharb
Cleveland Clinic
2024-02-01
Presenter: Abigail Meyers
Affidavit:
I certify that the material proposed for presentation in this abstract has not been published in any scientific journal or previously presented at a major meeting. The program director is responsible for making a statement within the confines of the box below specific to how much of the work on this project represents the original work of the resident. All authors/submitters of each abstract should discuss this with their respective program director for accurate submission of information as well as the program director's approval for inclusion of his/her electronic signature.
Director Name: Raymond Isakov
Author Category: Resident Plastic Surgery
Presentation Category: Basic Science Research
Abstract Category: General Reconstruction
Background:
This study aimed to identify transcriptomes predictive of clinical outcomes during ex vivo normothermic limb perfusion (EVNLP) and reperfusion.
Methods:
Bilateral porcine forelimbs underwent 24h EVNLP (n=3) or static cold storage (SCS, n=3), followed by 2h reperfusion. Muscle specimens were collected before procurement, q6h for 24h, q30m reperfusion. Reads from rtPCR were aligned to the sus scrofa genome to quantify transcript abundance. Differential expression and pathway analyses were performed.
Results:
Median weight change: -4.55% [-5.5- -0.86%] EVNLP, -0.4 [-7.2- -0.2%] SCS (p=0.72). During reperfusion, SCS limbs gained more: 22.4% [20.6-20.42%] versus 0.7% [0.45-2.85%] (p=0.009).
At reperfusion TP2h, SCS compartment pressures were higher: anterior 143±8mmHg versus 51±7mmHg (p=0.0001); posterior 85±11.3mmHg versus 29±1mmHg (p=0.001).
EVNLP upregulated expression of immune response and cellular stress pathways compared to baseline and SCS (p<0.05). Major upregulation was detected as early as 6h: 2,697 differentially expressed genes (DEGs) in EVNLP versus 42 in SCS (p<0.05).
Baseline versus reperfusion: 1,855 DEGs in EVNLP limbs (p<0.05), 182 in SCS (p<0.05). Between groups during reperfusion: 41 DEGs (p<0.05). From 24h EVNLP to reperfusion: 949 DEGs (p<0.05). Expression differed by only 3 genes for SCS limbs subject to reperfusion (p<0.05).
Conclusions:
EVNLP significantly upregulates immune and cellular stress pathways compared to baseline and SCS limbs as early as 6h. Interestingly, we found that reperfusion after 24 hours of cold storage does not induce the same level of gene expression as immediate perfusion, though compartment syndrome developed, suggesting that limbs stored on ice cannot benefit from reperfusion after a certain timepoint.
