O49 – Differential Immune and Hormonal Expression in Cardiac Versus Hepatic Blood after Burn Injury in Rodents

Author(s):Mile Stanojcic, Elena Bogdanovic, Marc Jeschke, Sunnybrook Health Sciences Centre

Background: Thermal injury is one of the most severe forms of trauma that a person can experience. The use of animal models of burn injury has enabled the ability to overcome clinical limitations through experimental design. Typically, the assessment of serological measures is limited to samples taken from cardiac puncture.

Hypothesis: The following study investigates the immune and hormonal profiles of control and burn mice by comparing blood collected from cardiac and hepatic portal vein blood. Furthermore, it will elucidate whether the portal system including small and large bowel as well as adipose tissue, has a different metabolic and inflammatory profile.

Methods: Thirty-Six balb/c mice (4-6 weeks old) were included in the study and divided into non-burn control (n=14) and burn (n=22) groups. Within each group, blood was collected from either cardiac (control, n=12; burn, n=17) or hepatic portal blood (control, n=2; burn, n=5). A multi-analyte Milliplex (Millipore, MA) platform was used to measure inflammatory and hormonal cytokines in plasma samples. Data was analyzed using mann-whitney, students t-test and ANOVA for differences in terms of collection location and experimental group.

Results: There was a significantly greater concentration of several pro-inflammatory, metabolic and proliferative cytokine measures in burn cardiac blood than control: GM-CSF, IL-6, IP-10, CXCL1 and Peptide YY. When comparing the location of blood collection in burns exclusively, hepatic portal vein had a decreased proportion of IL-1α, IP-10, MCP-1, MIP-1α, MIP-1β and Rantes. Interestingly, the adipokine Leptin was significantly lower in burn hepatic blood than burn cardiac and control cardiac (62±42, 1032±281 and 2206±878, p<0.05 respectively).

Conclusions: The alterations in inflammatory cytokines and metabolic hormones between non-burn controls and burn mice differ depending on the collection site. These findings suggest that that the portal hormonal and inflammatory profile is significantly different to cardiac derived and indicates localized responses in the intra-abdominal organs drained by the portal system. Thus, caution should be made when investigating such parameters exclusively from cardiac-derived blood and future studies should incorporate this collection practice to reflect this linear relationship.