Kidney Normothermic Machine Perfusion Can Be Used as a Preservation Technique and a Model of Reperfusion to Deliver Novel Therapies and Assess Inflammation and Immune Activation

Abstract

Ischaemia–reperfusion injury (IRI) is an inevitable process in transplantation and results in inflammation and immune system activation. Alpha-1 antitrypsin (AAT) has anti-inflammatory properties. Normothermic machine perfusion (NMP) can be used to deliver therapies and may help in assessing the effects of IRI and immunity. This study investigated the effects of AAT on IRI and inflammation in pig kidneys when administered during preservation, followed by normothermic reperfusion (NR) with autologous whole blood, as a surrogate for transplant. Two different models were used to deliver AAT or placebo to paired slaughterhouse pig kidneys: Model 1: 7-h static cold storage (SCS) + 3-h NR (n = 5 pairs), where either AAT (10 mg/ml) or placebo was delivered in the flush following retrieval; Model 2: 4-h SCS + 3-h NMP + 3-h NR (n = 5 pairs), where either AAT or placebo was delivered during NMP. Injury markers and cytokines levels were analysed in the perfusate, and heat shock protein 70 KDa (HSP-70) was analysed in biopsies. AAT delivered to kidneys showed no adverse effects on perfusion parameters. HSP-70 fold changes were significantly lower in the AAT group during NMP (P < 0.01, paired t-test) but not during NR. Interleukin-1 receptor antagonist (IL-1ra) fold changes were significantly higher in the AAT group during NR model 1 (p < 0.05, two-way ANOVA). In contrast to the AAT group, significant upregulation of interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) between t = 90 min and t = 180 min and interleukin-8 (IL-8) between baseline and t = 90 min was observed in the control group in NR model 2 (p < 0.05, Tukey’s multiple comparison test). However, overall inflammatory cytokines and injury markers showed similar levels between groups. Delivery of AAT to pig kidneys was safe without any detrimental effects. NMP and NR provided excellent methods for comparison of inflammation and immune activation in the delivery of a novel therapy.

Ex vivo normothermic preservation of a kidney graft from uncontrolled donation after circulatory death over 73 hours

“…At present, one of the most important efforts of the kidney transplant community is focused on prolonging the ex vivo preservation time of kidney grafts, not only to allow for long-distance kidney graft transportation but also to assess the viability of marginal kidney grafts (Kaths et al, 2018). Furthermore, long-term normothermic perfusion can transform NMP into a valuable system for the translation of innovative medicine strategies to clinical practice, especially those focused on cell and vector delivery to organ conditioning and reprogramming (Gregorini et al, 2017;Thompson et al, 2021;Mellati et al, 2022;Thompson et al, 2022).…”

Differential Cytokine Levels during Normothermic Kidney Perfusion with Whole Blood- or Red Blood Cell-Based Perfusates—Results of a Scoping Review and Experimental Study

“…From the reference lists, another 528 potential papers were identified, of which one was included (Figure S1 shows the flow chart). In total, 19 articles were included in this review [6,7,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. All reported on experimental studies (15 pig kidneys [6,[15][16][17][18][19][20][21][22][23][24][25][26][27]30], four human kidneys assessed as not suitable for transplantation [7,28,29,31]), one study also included data from transplanted human kidneys [7] (Table 1).…”

“…In total, 19 articles were included in this review [6,7,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. All reported on experimental studies (15 pig kidneys [6,[15][16][17][18][19][20][21][22][23][24][25][26][27]30], four human kidneys assessed as not suitable for transplantation [7,28,29,31]), one study also included data from transplanted human kidneys [7] (Table 1). Cytokines were mostly investigated in the perfusate (n = 10 [6,7,20,22,24,26-28,30,31]), followed by urine (n = 6 [7,[15][16][17][18][19][20][21]23,…”

Normothermic ex vivo perfusion of deceased donor kidneys and its clinical potential in kidney transplantation outcomes

“…Perfusate composition may also involve the delivery of a therapeutic agent during perfusion. In a porcine kidney perfusion model, Mellati et al 16 demonstrates the feasibility of introducing alpha-1 antitrypsin (AAT) during NMP after the priming solution begins circulating through the perfusion circuit. A protease inhibitor, AAT, may offer a potential therapeutic mechanism to respond to kidney inflammation and immune activation from IRI.…”

“…As a preservation technique, NMP mitigates the presentation of ischemia-related complications often seen in grafts preserved via static cold storage (SCS). [14][15][16] Thus, NMP can promote kidney function and suppress consequences related to SCS. As a potentially new assessment tool, NMP may serve as a more accurate screening mechanism to assess graft potential and viability, and lower the number of discarded kidneys at risk for delayed graft function (DGF) and graft failure.…”