J. Rosado1, A. Alvarez1, K. P. Oberoi1, G. Dikdan1, S. R. Pentakota1, S. Husain2, B. Koneru1 1Rutgers New Jersey Medical School,Surgery,Newark, NEW JERSEY, USA 2Rutgers New Jersey Medical School,Genomics Center,Newark, NJ, USA
Introduction: Remote ischemic conditioning (RIC) modulates inflammation after ischemia reperfusion, and may decrease postsurgical inflammation and complications. Here we present preliminary data regarding peripheral blood leukocyte gene expression in subjects from a prospective randomized a phase II clinical trial of RIC in progress (NCT03234543).
Methods: Adults undergoing abdominal surgery (duration > 2 hours, hospital stay > 2 days) are randomized (1:1) to receive either RIC or sham intervention immediately before surgery and on postoperative days 1 and 2. Each RIC intervention comprises 3 cycles of 5/5 minutes of inflation/deflation of mid-thigh cuff in one lower extremity. Inflation pressures were 250 mmHg for the first and systolic pressures plus 50 mmHg for the others. Sham interventions comprise cuff inflation pressure of 20 mmHg. Primary outcome is 30-day complications measured as comprehensive complications index. Peripheral blood was collected for plasma and RNA before (R0) and 1hr post surgery (R1), and 1 hour after 2nd and 3rd interventions (R2 and R3). Leukocyte mRNA transcripts were examined in R0 and R3 samples of both groups using RNA sequencing (30 million reads) for global expression profiles (n=6 each; fold change >1.5 and false discovery rate p<0.05) and RT-PCR for cytokine transcripts (IL-1β, IL-6, IL-8, IL-10, and TNF-α; n=8 each; Wilcoxon p< 0.05).
Results: 45 of planned 100 subjects (23/22 RIC/No RIC groups) were enrolled. At baseline (R0), mRNA profiles significantly differed between two groups in only 14 transcripts, and none were related to inflammation. 122 transcripts had significant differential expression between two groups at R3. 39/122 were transcripts of immunoglobulins, and expression levels of all were increased in No RIC. Importantly, TMED7, LGALS2, GZMH, and IL32 transcripts encoding proteins, which promote inflammation via IL-1 signaling, macrophage M1 phenotype, granzyme, and p38 kinase and NF-kb pathways, respectively were increased in No RIC. Transcripts of RELL1, IL1RAP, FKBP5, which encode member of TNF-a receptor family, IL-1 receptor accessory protein, and a cellular glucocorticoid responsiveness protein, respectively were decreased in No RIC. RT-RCR data showed a trend towards increased expression of IL-10 in No RIC that did not reach significance (p=0.10).
Conclusion: Preliminary results from this novel trial suggest that remote ischemic conditioning in the perioperative period down regulates expression of leukocyte proinflammatory genes. Further studies of gene expression in additional subjects and other time points and studies of plasma acute phase proteins and complement components are in progress. Also, the associations between the molecular data and the primary outcome will be examined.