WHOLE BLOOD RESUSCITATION RESTORES INTESTINAL PERFUSION AND INFLUENCES GUT MICROBIOME DIVERSITY.

OBJECTIVE Gut dysbiosis, an imbalance in the gut microbiome, occurs after trauma which may be ameliorated with transfusion. We hypothesized that gut hypoperfusion following trauma causes dysbiosis and that whole blood (WB) resuscitation mitigates these effects. METHODS Anesthetized rats underwent sham (S; laparotomy only, n = 6), polytrauma (T; laparotomy, liver and skeletal muscle crush injuries and femur fracture, n = 5), polytrauma and 40% hemorrhage (H; n = 7) and polytrauma, hemorrhage and WB resuscitation (R; n = 7) which was given as 20% estimated blood volume from donor rats 1 hr post-trauma. Baseline cecal mesenteric tissue oxygen (O2) concentration was measured following laparotomy and at 1- and 2 hrs post-trauma. Fecal samples were collected pre-injury and at euthanasia (2 hrs). 16 s rRNA sequencing was performed on purified DNA, and diversity and phylogeny analyzed with QIIME using the Greengenes 16S rRNA database (OTUs; 97% similarity). Alpha- and β-diversity were estimated using observed species metrics. Permutational analysis of variance was performed for overall significance. RESULTS In H rats, an average decline of 36% ±3.6 was seen in the mesenteric O2 concentration at 1 hr without improvement by 2 hrs post-injury, which was reversed following resuscitation at 2 hrs post-injury (4.1% ±3.1 difference from baseline). There was no change in tissue O2 concentration in the S or T rats. β-diversity differed amongst groups for all measured indices except Bray-Curtis, with the spatial median of the S and R rats more similar compared to S and H rats (p < 0.05). While there was no difference in α-diversity found amongst the groups, indices were significantly correlated with mesenteric O2 concentration. Members of the family Enterobacteriaceae were significantly enriched in only 2 hrs. CONCLUSIONS Mesenteric perfusion after trauma and hemorrhage is restored with WB resuscitation, which influences β-diversity of the gut microbiome. WB resuscitation may also mitigate the effects of hemorrhage on intestinal dysbiosis, thereby influencing outcomes. LEVEL OF EVIDENCE N/A - Basic ScienceStudy TypeOriginal Article.