Preclinical Modeling of DCD Class III Donation: Paving the Way for the Increased Use of This Challenging Donor Type

Abstract

Deceased after circulatory death (DCD) donors offer a viable solution to the current organ shortage, particularly the Maastricht Class III (arrest subsequent to cessation of life support in the hospital). Although current results from these donors are very satisfactory, the number of included donors is too low and future expansion of inclusion criteria will likely decrease organ quality, with negative consequences on the complication rate. This donor type thus represents a priority in terms of scientific exploration, so as to study it in controlled settings and prepare for future challenges. Hence, we mimicked the DCD Class III clinical conditions a Large White pig model. Herein, we detail the different strategies attempted to attain our objectives, including technical approaches such as animal positioning and ventilator settings, as well as pharmacological intervention to modulate blood pressure and heart rate. We highlight the best combination of factors to successfully reproduce DCD Class III conditions, with perfusion pressures and functional warm ischemia (hypoperfusion) closely resembling clinical situations. Finally, we detail the functional and histological impacts of these conditions. Such a model could be of critical value to explore novel management alternative for these donors, presenting a uniquely adapted platform for such therapeutics as normothermic regional circulation and/or pharmacological intervention.

Figure 1

Schematic representation of the DCD ClassIII guidelines formulated by the ABM: Agonal period (between life support cessation and circulatory arrest) must last under 180min, and within this time window the hypoperfusion time (i.e., between the point when mean arterial pressure, MAP, drops below 45 mmHg and circulatory arrest) must be under 120min. Once circulatory arrest is determined, there is a 5min no touch period before death is declared and organs can be procured. Further management considerations such as normothermic regional circulation are currently being discussed.

Figure 2

Donor surveillance parameters: Pigs were followed during the protocol for key parameters in the DCD Class III definition. (a) Mean Arterial pressure; (b) Heart Rate; (c) Cardiac Output; (d) EtCO2. Shown are individual data points as well as mean±SD. Statistics were performed with the Friedman test. Overall p value in the Friedman test was 0.014 for MAP, <0.001 for Heart Rate, 0.012 for Cardiac output, and <0.001 for EtCO2.

Figure 3

Biological parameters and circulating markers of injury: Pigs were followed during the protocol for biochemical parameters. (a) Serum creatinine; (b) Aspartate Aminotransferase; (c) Lactate dehydrogenase; (d) Alanine Aminotransferase. Shown are individual data points as well as mean±SD. Statistics were performed with the Friedman test. Overall p value in the Friedman test was <0.001 for creatininemia, <0.001 for LDH, <0.001 for ASAT and 0.062 for ALAT.

Figure 4

Circulating markers of inflammation: Pigs were followed during the protocol for inflammation markers. (a) High–Mobility Group box 1; (b) Tumor Necrosis Factor α; (c) Interleukin 6. Shown are individual data points as well as mean±SD. Statistics were performed with the Friedman test.

Figure 5

Anatomopathological evaluation of kidney histology at the end of MIII protocol: Representative images of histology are presented. A: HE coloration, renal cortex: normal tissue (From Animal I; Magnification 400X), DCT: distal convoluted tubule, PCT: proximal convoluted tubule; B: HE coloration, renal cortex: foci of necrosis (From Animal VI, Magnification: 200X) C: HE coloration, renal cortex: foci of necrosis (From Animal VI, Magnification: 400X).