Histopathological injury.

<p>(A) Morphological damage peaked after 24 hours of reperfusion. Semi-quantitative scoring resulted in a markedly reduced total score in the RIC groups vs. Control (mean±IQR, **p<0.01 RIC 1 vs. Control, Kruskal-Wallis H Test, n = 6/group/time point). (B) Representative photos of the histological specimens following transplantation and 24 h reperfusion (stained with hematoxylin-eosin; original magnification 100x). Mild-moderate grade hepatocyte degeneration, vacuolization, tissue necrosis and hemorrhage as well as inflammation were observed on the slides of all the three experimental groups; nevertheless, a milder injury was seen on the slides of the RIC 1 and 2 groups (arrows). Abbreviations used: RIC-remote ischemic conditioning.</p

Liver tissue HO-1 encoding mRNA.

<p>mRNA expression of HO-1 increased markedly after 3 hours of reperfusion compared to the physiological levels (mean±SD, ***p<0.001 Experimental groups vs. Healthy control, one-way ANOVA, n = 6/group/time point). RIC treatment could further increase HO-1 expression resulting in a significant difference between RIC 1 group vs. Control. (mean±SD, *p<0.05 RIC 1 vs. Control, one-way ANOVA, n = 6/group/time point). Dotted line = physiological values in healthy animals. Abbreviations used: RQ-relative quantification; RIC-remote ischemic conditioning; HO-1-heme oxygenase-1.</p

Study flowchart and microsurgical technique.

<p>Animals were randomized into three experimental groups (Control, RIC 1, RIC 2). Following liver retrieval, grafts were stored for 8 h in cold HTK solution and implanted into the recipient animals. In the RIC 1 and RIC 2 groups, remote conditioning (4x5 min IR via exclusion of the infrarenal aorta) was applied before the anhepatic phase or after reperfusion, respectively. Short waiting periods have been implemented to keep the recipient procedures in the same time range in all experimental groups. Animals were sacrificed after 1, 3, 24, and 168 h of reperfusion for sample collection and further analysis (n = 6/group/time point). Representative photographs are demonstrating the used microsurgical approach for liver transplantation. Original magnification 8-16x. SHIVC: 7–0 Prolene one-way up running suture; IHIVC: 8–0 Prolene one-way up running suture; PV: Cuff technique, using 14 G cuffs; CBD and HA: Splinting with 24 G polyethylene splints. Abbreviations used: CIT-cold ischemic time; HTK-Histidine-tryptophan-ketoglutarate solution; AP-anhepatic phase; IVC-CT-inferior vena cava clamping time; HA-hepatic artery; CBD-common bile duct; WP-waiting period; RIC-remote ischemic conditioning; IR-ischemia reperfusion; SHIVC-supra hepatic inferior vena cava; IHIVC-infra hepatic inferior vena cava; PV-portal vein.</p

Experimental and clinical studies with remote ischemic conditioning and liver transplantation (search date: 26^th of January 2018).

<p>Experimental and clinical studies with remote ischemic conditioning and liver transplantation (search date: 26^th of January 2018).</p

Hepatocellular injury and inflammatory cytokines.

<p>(A; B; C) Time course of transaminases and LDH demonstrated the peak of hepatocellular injury after 24 and 3 h, respectively. The application of RIC significantly reduced transaminase and LDH release (mean±SD, *p<0.05, **p < 0.01,***p < 0.001 RIC 1 and RIC 2 vs. Control two-way ANOVA and Bonferroni post-hoc test, n = 6/group/time point). (D; E) Serum IL-10 was significantly increased in the early phase or reperfusion (1 h). The RIC 1 and RIC 2 protocols resulted in a further increment in the serum release of this anti-inflammatory master-cytokine. (mean±SD, *p<0.05, ***p<0.001 RIC 1 and RIC 2 vs. Control, respectively two-way ANOVA and Bonferroni post-hoc test, n = 6/group/time point). Levels of IL-10 decreased below threshold for detection after 24 hours. MCP-1 showed reciprocal characteristics, however, without significant between group differences. Abbreviations used: AST-aspartate aminotransferase; ALT-alanine aminotransferase; LDH-lactate dehydrogenase; IL-interleukin; MCP-Monocyte chemoattractant protein, RIC-remote ischemic conditioning.</p

Liver graft macro and microcirculation.

<p>(A; B) Time course of portal venous flow and pressure. Portal venous flow was significantly higher in the RIC 1 group compared to Control after 24 hours of reperfusion (mean±SD, *p<0.05 RIC 1 vs Control, two-way ANOVA and Bonferroni post-hoc test, n≥5/group/time point). No significant differences have been found in portal pressure. (C; D) Graft microcirculatory parameters measured with the O2C device, such as flow and velocity, remained higher in the RIC group compared to Control throughout the observation period. Microcirculation was significantly higher after 1 hour of reperfusion in the RIC 1 group vs. Control (mean±SD, *p<0.05 RIC 1 vs. Control, two-way ANOVA and Bonferroni post-hoc test, n = 6/group/time point). Similar trends but with marginally non-significant differences were found in the RIC 2 group. Dotted line = baseline values after laparotomy in healthy animals (n = 15). Abbreviations used: AU-arbitrary unit, O2C-oxygen to see.</p

Liver tissue ATP levels and lipid peroxidation.

<p>(A) RIC resulted in better preserved tissue ATP levels throughout the observation period. Significantly higher tissue ATP levels have been found in the RIC 1 group vs. Control after 3 h reperfusion. (mean±SD, **p<0.01 RIC 1 vs. Control, one-way ANOVA, n = 6/group/time point). (B) Extent of oxidative damage and lipid peroxidation (MDA) did not show significant between group differences. Abbreviations used: RIC-remote ischemic conditioning; ATP-adenosine triphosphate; MDA-malondialdehyde.</p