Peer Review #2 of "Random allogeneic blood transfusion in pigs: characterisation of a novel experimental model (v0.1)"

Abstract

Background: Organ cross-talk describes interactions between a primary affected organ and a secondarily injured remote organ, particularly in lung-brain interactions. A common theory is the systemic distribution of inflammatory mediators that are released by the affected organ and transferred through the bloodstream. The present study characterises the baseline immunogenic effects of a novel experimental model of random allogeneic blood transfusion in pigs designed to analyse the role of the bloodstream in organ cross-talk. Methods: After approval of the State and Institutional Animal Care Committee 20 anesthetized pig were randomized in a donor and an acceptor (each n=8): the acceptor animals each received high-volume whole blood transfusion from the donor (35-40 ml kg-1). Four animals received balanced electrolyte solution instead of blood transfusion (control group; n=4). Afterwards the animals underwent extended cardiorespiratory monitoring for eight hours. Post mortem assessment included pulmonary, cerebral and systemic mediators of early inflammatory response (IL-6, TNF-alpha, iNOS), wet to dry ratio, and lung histology. Results: No adverse events or incompatibilities occurred during the blood transfusion procedures. No hints for systemic inflammatory response were found and the pulmonary function was not affected through blood transfusion. Lung histopathology scoring did not display relevant intergroup differences. Neither within the lung nor within the brain an up-regulation of inflammatory mediators was detected. High volume random allogeneic blood transfusion in pigs neither impaired pulmonary integrity nor induced systemic, lung, or brain inflammatory response. Conclusion: This approach can represent a novel experimental model to characterize the blood-bound transmission in remote organ injury.