Preclinical Study of DCD and Normothermic Perfusion for Visceral Transplantation

Abstract

Considering recent clinical and experimental evidence, expectations for using DCD-derived intestines have increased considerably. However, more knowledge about DCD procedure and long-term results after intestinal transplantation (ITx) is needed. We aimed to describe in detail a DCD procedure for ITx using normothermic regional perfusion (NRP) in a preclinical model. Small bowel was obtained from pigs donors after 1 h of NRP and transplanted to the recipients. Graft Intestinal samples were obtained during the procedure and after transplantation. Ischemia-reperfusion injury (Park-Chiu score), graft rejection and transplanted intestines absorptive function were evaluated. Seven of 8 DCD procedures with NRP and ITx were successful (87.5%), with a good graft reperfusion and an excellent recovery of the recipient. The architecture of grafts was well conserved during NRP. After an initial damage of Park-chiu score of 4, all grafts recovered from ischemia-reperfusion, with no or very subtle alterations 2 days after ITx. Most recipients (71.5%) did not show signs of rejection. Only two cases demonstrated histologic signs of mild rejection 7 days after ITx. Interestingly intestinal grafts showed good absorptive capacity. The study's results support the viability of intestinal grafts from DCD using NRP, contributing more evidence for the use of DCD for ITx.

Keywords: donation after circulatory death; experimental DCD feasibility; intestinal graft viability; intestinal transplantation; normothermic perfusion.

FIGURE 1

Monitoring during NRP: Oxygen-derived parameters [indexed O₂ delivery (D_iO₂), indexed O₂ consumption (V_iO₂), O₂ extraction (ERO₂)], carbon dioxide-derived parameters (ΔpCO₂/DA-VO₂ Ratio), and lactate clearance were evaluated at different timepoints of NRP during donor procedure. NRP, normothermic regional perfusion.

FIGURE 2

Intestinal IRI analysis. Histological damage at different stages of the ITx procedure with DCD and NRP was studied using the PCS. Each point depicts a simple sample evaluation. (A) Microscopic representative images of an intestine after 60 min of NRP (B), 60 min, (C) and 2 days after graft reperfusion (D) (H/E-stained samples, ×10). APPS, after perfusion with preservation solution; ITx, intestinal transplantation; DCD, donation after circulatory death; NRP, normothermic regional perfusion; H/E, hematoxylin–eosin.

FIGURE 3

Graft rejection. Histological study in search of acute cellular rejection was performed using the Wu scheme (A). Most of the evaluated samples were normal (B). A few cases present microscopic alterations, consistent with mild rejection, (C) and only one case of severe rejection on POD 14 was observed (D). (H/E-stained samples, ×10). POD, postoperative day; H/E, hematoxylin–eosin.

FIGURE 4

Fold change gene expression values. Each line represents values from a single animal. Comparison between grafts and native intestines was made using an unpaired t-test. Significant p-values are plotted as follows: *: p < 0.05, **: p < 0.01, ***: p < 0.001.

FIGURE 5

Graft functional evaluation. Citrulline plasma levels increase after ITx. Each line represents values from a single recipient (A). The glucose absorption test of the transplanted intestines from DCD procedures was performed by introducing a glucose solution into them. The transplanted intestine was observed to have a good absorptive capacity. The glucose level increases peripherally and in native intestines as it is distributed through the body (B). Results are presented as the mean ± SEM. Significant p-values are plotted as follows: *: p < 0.05, **: p < 0.01, ***: p < 0.001. ITx, intestinal transplantation; DCD, donation after circulatory death; SEM, standard error of the mean.