Forsøksdyr: Inhibition of the inflammatory response in a porcine ex vivo model of renal ischemia/reperfusion injury (extended experimentation period due to SARS-CoV2 pandemia)

Godkjenningsdato 10.06.2020

Godkjenningsperiode 01.09.2020-30.08.2022

We got approved a previous application on the same subject (FOTS 8752). We planned to be done with all experiments until August 2020. However, the ongoing SARSCoV2 pandemia let to close-down of the laboratory and animal surgical facility. Thus, we can not conduct experiments and will not be able to conclude the ongoing study until end of August 2020. As it is not possible to apply for an extention, we thus apply here for the animals needed to conclude the former approved study and extend it to include both complement and TLR inhibition.

A transplanted kidney is exposed to episodes of ischemia (during explantation, transportation and implantation) and reperfusion (in the recipient) which mediate deleterious inflammatory responses and reduce the lifetime of the kidney graft. Our hypothesis is that complement activation and the TLRs are triggered by the stress of ischemia and reperfusion and that this leads to activation of inflammatory cells (leucocytes and endothelial cells), production of inflammatory mediators and direct damage to the kidney. In the longer view, this is hypothesized to reduce the lifetime of a transplanted kidney as also the adaptive immunereponse is activated by these immediate events leading to chronic graft failure.

We will employ isolated kidneys from pigs, perfuse them accordingly to the standard protocol of human kidneys for transplantation (explantation and storage) and in addition give inhibitors to prevent complement activation and activation of the TLR-system. After that, we will perfuse them ex vivo with pig whole blood. By doing this we aim to evaluate the contribution of these inflammatory pathways and meanwhile test a treatment protocol. We expect this to have a large value for the society; Kidney transplantation is a lifesaving treatment in renal disease and the most frequent solid-organ transplantation in the world. However, limited supply and limited lifetime of kidney grafts is an unsolved problem. If our therapy should be beneficial, this protocol could rather easily be employed in the situation of human kidney transplantation in order to preserve organ integrity.

We have included 6 pigs already and apply for additional 27 pigs. Each pig will be used both as organ and blood donor at the same time. The pigs will be anesthetized during the whole period of kidney isolation and blood collection. The animal will thereafter immediately be euthanized. We expect minimal stress of the animals and no pain. Today, replacement for the pig kidney is impossible. Kidney function is a primary read-out and for that purpose, we need a whole kidney. We are already running in vitro experiments on endothelial cells but for this purpose, we need a whole organ.

Our group has a large experience with pig experiments. The researchers already have experience of explantation of human kidneys and running the ex vivo machine perfusion. Therefore, we expect very low number of animals to re-establish this protocol. As we have already included 6 animals, the group sizes has however to be large enough not to lose statistical power and additional experiments therefore are warranted.