Ex Vivo Administration of Mesenchymal Stromal Cells in Kidney Grafts Against Ischemia-reperfusion Injury-Effective Delivery Without Kidney Function Improvement Posttransplant

BACKGROUND

Mesenchymal stromal cell (MSC) therapy may improve renal function after ischemia-reperfusion injury in transplantation. Ex vivo renal intraarterial administration is a targeted delivery method, avoiding the lung vasculature, a known barrier for cellular therapies. In a randomized and blinded study, we tested the feasibility and effectiveness of MSC therapy in a donation after circulatory death autotransplantation model to improve posttransplant kidney function, using an ex vivo MSC delivery method similar to the clinical standard procedure of pretransplant cold graft flush.

METHODS

Kidneys exposed to 75 minutes of warm ischemia and 16 hours of static cold storage were intraarterially infused ex vivo with 10 million male porcine MSCs (Tx-MSC, n = 8) or vehicle (Tx-control, n = 8). Afterwards, the kidneys were autotransplanted after contralateral nephrectomy. Biopsies an hour after reperfusion confirmed the presence of MSCs in the renal cortex. Animals were observed for 14 days.

RESULTS

Postoperatively, peak plasma creatinine was 1230 and 1274 µmol/L (Tx-controls versus Tx-MSC, P = 0.69). During follow-up, no significant differences over time were detected between groups regarding plasma creatinine, plasma neutrophil gelatinase-associated lipocalin, or urine neutrophil gelatinase-associated lipocalin/creatinine ratio. At day 14, measured glomerular filtration rates were 40 and 44 mL/min, P = 0.66. Renal collagen content and fibrosis-related mRNA expression were increased in both groups but without significant differences between the groups.

CONCLUSIONS

We demonstrated intraarterial MSC infusion to transplant kidneys as a safe and effective method to deliver MSCs to the graft. However, we could not detect any positive effects of this cell treatment within 14 days of observation.

The Use of the Oxygenated AirdriveTM Machine Perfusion System in Kidney Graft Preservation: A Clinical Pilot Study

BACKGROUND

The shortage of donor kidneys has led to the use of marginal donors, e.g., those whose kidneys are donated after circulatory death. Preservation of the graft by hypothermic machine perfusion (HMP) provides a viable solution to reduce warm ischemic damage. This pilot study was undertaken to assess the feasibility and patient safety of the AirdriveTM HMP system in clinical kidney transplantation.

METHODS

Five deceased-donor kidneys were preserved using the oxygenated Airdrive HMP system between arrival at the recipient center (Amsterdam UMC) and implantation in the patient. The main study end-points were adverse effects due to the use of Airdrive HMP. Secondary end-points were clinical outcomes and perfusion parameters. All events occurring during the transplantation procedure or within 1 month of follow-up were monitored.

RESULTS

Five patients were included in this pilot study. No technical failures were observed during the preservation period using the Airdrive HMP. Mean perfusion parameters were: duration 8.5 h (3-15 h), pressure 25 mm Hg (18-25 mm Hg), flow 49.77 mL/min (19-58 mL/min), resistance 0.57 mm Hg/min/mL (0.34-1.3 mm Hg/min/mL), and temperature 8.2 °C (2-13°C). Mean cold ischemia time (CIT) was 20.2 h (11-29.5 h). No adverse events or technical failures were observed during preservation and transplantation or during the 1-month follow-up.

CONCLUSIONS

This pilot study showed the feasibility of the use of the Airdrive HMP system with no adverse events in clinical kidney transplantation.

A Pilot Study of Postoperative Animal Welfare as a Guidance Tool in the Development of a Kidney Autotransplantation Model With Extended Warm Ischemia

This pilot study aimed to maintain acceptable animal welfare in the development of a porcine autotransplantation model with severe and incremental renal ischemic injury, a model for usage in future intervention studies. Secondary aims were to develop and test methods to collect blood and urine without the need to restrain or use sedative and avoid transportation to optimize welfare of the pig.

An Oxygenated and Transportable Machine Perfusion System Fully Rescues Liver Grafts Exposed to Lethal Ischemic Damage in a Pig Model of DCD Liver Transplantation

BACKGROUND

Control of warm ischemia (WI) lesions that occur with donation after circulatory death (DCD) would significantly increase the donor pool for liver transplantation. We aimed to determine whether a novel, oxygenated and hypothermic machine perfusion device (HMP Airdrive system) improves the quality of livers derived from DCDs using a large animal model.

METHODS

Cardiac arrest was induced in female large white pigs by intravenous injection of potassium chloride. After 60 minutes of WI, livers were flushed in situ with histidine-tryptophan-ketoglutarate and subsequently preserved either by simple cold storage (WI-SCS group) or HMP (WI-HMP group) using Belzer-MPS solution. Liver grafts procured from heart-beating donors and preserved by SCS served as controls. After 4 hours of preservation, all livers were transplanted.

RESULTS

All recipients in WI-SCS group died within 6 hours after transplantation. In contrast, the HMP device fully protected the liver against lethal ischemia/reperfusion injury, allowing 100% survival rate. A postreperfusion syndrome was observed in all animals of the WI-SCS group but none of the control or WI-HMP groups. After reperfusion, HMP-preserved livers functioned better and showed less hepatocellular and endothelial cell injury, in agreement with better-preserved liver histology relative to WI-SCS group. In addition to improved energy metabolism, this protective effect was associated with an attenuation of inflammatory response, oxidative load, endoplasmic reticulum stress, mitochondrial damage, and apoptosis.

CONCLUSIONS

This study demonstrates for the first time the efficacy of the HMP Airdrive system to protect liver grafts from lethal ischemic damage before transplantation in a clinically relevant DCD model.

Short, Cool, and Well Oxygenated - HOPE for Kidney Transplantation in a Rodent Model

OBJECTIVES

The aim of this study was to investigate novel and easily applicable preservation perfusion techniques in kidney grafts obtained from donors after circulatory death (DCD).

BACKGROUND

A novel perfusion approach, hypothermic oxygenated perfusion (HOPE), used for DCD liver grafts, is based on cold perfusion for 1 hour by an oxygenated solution before implantation. Here, we aimed to test HOPE in a rodent model of kidney grafts associated with substantial warm ischemia.

METHODS

Rat kidneys were exposed to 30 minutes in situ warm ischemia, without application of heparin. Kidneys were removed and cold stored for 4 and 18 hours, mimicking DCD organ procurement and conventional preservation. In additional experiments, kidneys were normothermically perfused with oxygenated blood for 1 hour after cold storage. In a third group, kidneys were perfused by HOPE for 1 hour after cold storage. In each group, orthotopic kidney transplantation was performed after recipient nephrectomy.

RESULTS

HOPE-treated DCD kidneys showed dramatically better function after transplantation, than cold-stored grafts in terms of nuclear injury, macrophage activation, endothelium activation, tubulus damage, and graft function. A short period of warm oxygenated perfusion before implantation improved graft quality as compared with cold storage, but was significantly less effective in all endpoints compared with HOPE. The effect of HOPE was dependent on perfusate oxygenation in the cold.

CONCLUSIONS

HOPE of DCD kidneys was superior to other clinically used preservation approaches, consistent to earlier results in livers. On the basis of this, we assume a strong and generalized effect on solid organ viability by HOPE before transplantation. These results justify a clinical trial.

Maximizing kidneys for transplantation using machine perfusion: from the past to the future: A comprehensive systematic review and meta-analysis

BACKGROUND

The two main options for renal allograft preservation are static cold storage (CS) and machine perfusion (MP). There has been considerably increased interest in MP preservation of kidneys, however conflicting evidence regarding its efficacy and associated costs have impacted its scale of clinical uptake. Additionally, there is no clear consensus regarding oxygenation, and hypo- or normothermia, in conjunction with MP, and its mechanisms of action are also debated. The primary aims of this article were to elucidate the benefits of MP preservation with and without oxygenation, and/or under normothermic conditions, when compared with CS prior to deceased donor kidney transplantation.

METHODS

Clinical (observational studies and prospective trials) and animal (experimental) articles exploring the use of renal MP were assessed (EMBASE, Medline, and Cochrane databases). Meta-analyses were conducted for the comparisons between hypothermic MP (hypothermic machine perfusion [HMP]) and CS (human studies) and normothermic MP (warm (normothermic) perfusion [WP]) compared with CS or HMP (animal studies). The primary outcome was allograft function. Secondary outcomes included graft and patient survival, acute rejection and parameters of tubular, glomerular and endothelial function. Subgroup analyses were conducted in expanded criteria (ECD) and donation after circulatory (DCD) death donors.

RESULTS

A total of 101 studies (63 human and 38 animal) were included. There was a lower rate of delayed graft function in recipients with HMP donor grafts compared with CS kidneys (RR 0.77; 95% CI 0.69-0.87). Primary nonfunction (PNF) was reduced in ECD kidneys preserved by HMP (RR 0.28; 95% CI 0.09-0.89). Renal function in animal studies was significantly better in WP kidneys compared with both HMP (standardized mean difference [SMD] of peak creatinine 1.66; 95% CI 3.19 to 0.14) and CS (SMD of peak creatinine 1.72; 95% CI 3.09 to 0.34). MP improves renal preservation through the better maintenance of tubular, glomerular, and endothelial function and integrity.

CONCLUSIONS

HMP improves short-term outcomes after renal transplantation, with a less clear effect in the longer-term. There is considerable room for modification of the process to assess whether superior outcomes can be achieved through oxygenation, perfusion fluid manipulation, and alteration of perfusion temperature. In particular, correlative experimental (animal) data provides strong support for more clinical trials investigating normothermic MP.

Sinusoidal obstruction syndrome in the animal model: influence on liver surgery

PURPOSE

In recent years, multimodal treatment approaches have led to an increased median survival time of patients with colorectal liver metastases. In particular, this results from new perioperative chemotherapy regimens, which in turn are accompanied by an increased risk of perioperative bleeding and/or liver failure due to the hepatotoxic side effects. Nineteen to 58 % of patients treated with oxaliplatin develop sinusoidal obstruction syndrome (SOS). The influence of preexisting SOS on liver surgery remains controversial.

METHODS

Animals were operated 4 days after SOS induction with monocrotaline and received either vascular occlusion in the form of Pringle maneuver (PM) or hepatectomy (LR; 70 %) or a combination of both (LR + PM). Postoperative liver function was assessed by determination of liver enzyme levels, bile production, and tissue oxygen saturation.

RESULTS

Preexisting SOS impaired morbidity after liver resection, reflected by elevated liver enzyme levels, reduced bile secretion, and low liver tissue oxygenation levels. Mortality was increased by up to 25 %. Additional ischemia in the form of PM showed no further impact in the LR ± PM group compared to LR alone.

CONCLUSION

PM without LR results in high enzyme distribution in the SOS group. SOS significantly affects the outcome after liver resection in our experimental rat model only without PM and showed no protective effect in ischemia in the form of PM.

Comparison of Aerobic Preservation by Venous Systemic Oxygen Persufflation or Oxygenated Machine Perfusion of Warm-Ischemia-Damaged Porcine Kidneys

Background/Aim: The global shortage of donor organs for transplantation has necessitated the expansion of the organ pool through increased use of organs from less ideal donors. Venous systemic oxygen persufflation (VSOP) and oxygenated machine perfusion (OMP) have previously demonstrated beneficial results compared to cold storage (CS) in the preservation of warm-ischemia-damaged kidney grafts. The aim of this study was to compare the efficacy of VSOP and OMP for the preservation of warm-ischemia-damaged porcine kidneys using the recently introduced Ecosol preservation solution compared to CS using Ecosol or histidine-tryptophan-ketoglutarate solution (HTK). Materials and Methods: Kidneys from German Landrace pigs (n = 5/group) were retrieved and washed out with either Ecosol or HTK after 45 min of clamping of the renal pedicle. As controls, kidneys without warm ischemia, cold stored for 24 h in HTK, were employed. Following 24 h of preservation by VSOP, OMP, CS-Ecosol, or CS-HTK, renal function and damage were assessed during 1 h using the isolated perfused porcine kidney model. Results: During reperfusion, urine production was significantly higher in the VSOP and OMP groups than in the CS-HTK group; however, only VSOP could demonstrate lower urine protein concentrations and fractional excretion of sodium, which did not differ from the non-warm-ischemia-damaged control group. VSOP, CS-Ecosol, and controls showed better maintenance of the acid-base balance than CS-HTK. Reduced lipid peroxidation, as reflected in postreperfusion tissue thiobarbituric acid-reactive substance levels, was observed in the VSOP group compared to the OMP group, and the VSOP and CS-Ecosol groups had concentrations similar to the controls. The ratio of reduced to oxidized glutathione was higher in the VSOP, OMP, and CS-Ecosol groups than in the CS-HTK group and controls, with a higher ratio in the VSOP than in the OMP group. Conclusion: VSOP was associated with mitigation of oxidative stress in comparison to OMP and CS. Preservation of warm-ischemia-damaged porcine kidneys by VSOP was improved compared to OMP and CS, and was comparable to preservation of non-warm-ischemia-damaged cold-stored kidneys.

First clinical experience with polysol solution: pilot study in living kidney transplantation

In this study, we assessed the safety of the new organ preservation solution polysol solution in the clinical setting of living kidney transplantation. We conducted a prospective pilot study in nine adult donor-recipient couples using polysol solution for washout and cold storage of kidney grafts. Adverse reactions possibly related to the use of polysol solution as well as renal function at 1, 6, and 12 months after transplantation were monitored. All living kidney transplantation performed in adults in our center within 2002 to 2008 using the University of Winconsin solution served as controls (n = 190). The use of polysol solution was associated with a higher acute rejection rate compared to University of Wisconsin solution at all time points. Also, antibody-mediated rejection occurred more frequently in the polysol group. Renal function at all time points was also comparable between the groups. This pilot study in living kidney transplantation is the first clinical study on the use of polysol solution. Although the study was not powered on the endpoint rejection, we observed a high number of acute rejection and antibody-mediated rejection episodes in recipients of polysol solution preserved grafts as compared to University of Wisconsin solution controls. As a consequence the study was terminated prematurely.

A novel oxygenated machine perfusion system for preservation of the liver

Machine perfusion (MP) is a potential method to increase the donor pool for organ transplantation. However, MP systems for liver grafts remain difficult to use because of organ-specific demands. Our aim was to test a novel, portable MP system for hypothermic preservation of the liver. A portable, pressure-regulated, oxygenated MP system designed for kidney preservation was adapted to perfuse liver grafts via the portal vein (PV). Three porcine livers underwent 20 h of hypothermic perfusion using Belzer MP solution. The MP system was assessed for perfusate flow, temperature, venous pressure, and pO2 /pCO2 during the preservation period. Biochemical and histological parameters were analyzed to determine postpreservation organ damage. Perfusate flow through the PV increased over time from 157 ± 25 mL/min at start to 177 ± 25 mL/min after 20 h. PV pressure remained stable at 13 ± 1 mm Hg. Perfusate temperature increased from 9.7 ± 0.6°C at the start to 11.0 ± 0.0°C after 20 h. Aspartate aminotransferase and lactate dehydrogenase increased from 281 ± 158 and 308 ± 171 U/L after 1 h to 524 ± 163 and 537 ± 168 U/L after 20 h, respectively. Blood gas analysis showed a stable pO2 of 338 ± 20 mm Hg before perfusion of the liver and 125 ± 14 mm Hg after 1 h perfusion. The pCO2 increased from 15 ± 5 mm Hg after 1 h to 53 ± 4 mm Hg after 20 h. No histological changes were found after 20 h of MP. This study demonstrated the feasibility of a portable MP system for preservation of the liver and showed that continuous perfusion via the PV can be maintained with an oxygen-driven pump system without notable preservation damage of the organ.

Optimal flow and pressure management in machine perfusion systems for organ preservation

Intra-organ flow is the most critical parameter in machine-perfused organ preservation systems (MPS). Ultrasonic flow sensors (UFS) are commonly employed in MPS. However, UFS are sensitive to changes in fluid composition and temperature and require recalibration. Novel Coriolis-type mass flow sensors (CFS) may be more suitable for MPS because the measurement technique is not amenable to these factors. The effect of viscosity, colloids, temperature, pressure, and preservation solution on flow measurement accuracy of UFS and CFS was therefore investigated. A CFS-based MPS was built and validated for setpoint stability using porcine kidneys and the ability to reproduce different pressure and flow waveforms. The UFS exhibited a temperature- and preservation solution-dependent overestimation of flow rate compared to the CFS. The CFS deviated minimally from the actual flow rate and did not require recalibration. The CFS-based MPS conformed to the preprogrammed temperature, flow, pressure, and vascular resistance settings during 6-h kidney preservation. The system was also able to accurately reproduce different pressure and flow waveforms. Conclusively, CFS-based MPS are more suitable for organ preservation than UFS-based MPS. Our CFS-based MPS provides a versatile yet robust experimental platform for testing and validating different types of clinical and experimental MPS.

Hypothermic machine perfusion after static cold storage does not improve the preservation condition in an experimental porcine kidney model

Background

Combining hypothermic techniques, as a more practical approach to preservation, may enhance the condition of kidneys donated after cardiac death.

Methods

Porcine kidneys were retrieved after 10 min in situ warm ischaemia, then preserved by either 18 h static cold storage (CS), hypothermic machine perfusion for 18 h (HMP) or 14 h static CS followed by 4 h HMP (4HMP). Kidneys were reperfused for 3 h with oxygenated autologous blood on an isolated organ perfusion system to assess renal function and injury.

Results

Intrarenal resistance was significantly higher in the 4HMP group than in the CS and HMP groups: mean(s.d.) area under the curve (AUC) 8·48(2·97), 3·41(1·80) and 3·78(1·68) mmHg/min.h respectively (P = 0·011). Creatinine clearance was lower after 4HMP and CS: AUC 2·3(0·6) and 2·2(1·7) ml per min per 100g.h respectively versus 9·8(7·3) ml per min per 100g.h in the HMP group (P = 0·022). Levels of endothelin 1 were higher in the 4HMP and CS groups: mean(s.d.) 21·6(4·0) and 24·2(2·3) pg/ml respectively versus 11·4(4·6) pg/ml in the HMP group (P = 0·002). Morphological damage was increased in the 4HMP group.

Conclusion

This porcine kidney study demonstrated no advantage to the addition of 4 h of HMP after CS.

Analysis of machine perfusion benefits in kidney grafts: a preclinical study

Background

Machine perfusion (MP) has potential benefits for marginal organs such as from deceased from cardiac death donors (DCD). However, there is still no consensus on MP benefits. We aimed to determine machine perfusion benefits on kidney grafts.

Methods

We evaluated kidney grafts preserved in ViaspanUW or KPS solutions either by CS or MP, in a DCD pig model (60 min warm ischemia + 24 h hypothermic preservation). Endpoints were: function recovery, quality of function during follow up (3 month), inflammation, fibrosis, animal survival.

Results

ViaspanUW-CS animals did not recover function, while in other groups early follow up showed similar values for kidney function. Alanine peptidase and β-NAG activities in the urine were higher in CS than in MP groups. Oxydative stress was lower in KPS-MP animals. Histology was improved by MP over CS. Survival was 0% in ViaspanUW-CS and 60% in other groups. Chronic inflammation, epithelial-to-mesenchymal transition and fibrosis were lowest in KPS-MP, followed by KPS-CS and ViaspanUW-MP.

Conclusions

With ViaspanUW, effects of MP are obvious as only MP kidney recovered function and allowed survival. With KPS, the benefits of MP over CS are not directly obvious in the early follow up period and only histological analysis, urinary tubular enzymes and red/ox status was discriminating. Chronic follow-up was more conclusive, with a clear superiority of MP over CS, independently of the solution used. KPS was proven superior to ViaspanUW in each preservation method in terms of function and outcome. In our pre-clinical animal model of DCD transplantation, MP offers critical benefits.

Hypothermic machine perfusion of kidney grafts: which pressure is preferred?

To assess the effect of the perfusion pressure (PP) during machine perfusion (MP) on the preservation quality of kidney grafts, we compared mean PPs of 25 and 30 mmHg using a porcine autotransplantation model. After assessment of the microcirculation, animals underwent left nephrectomy. Thereafter, kidneys were washed out followed by 20 h of MP at 25 mmHg (MP25, n = 7) or 30 mmHg (MP30, n = 7) using a novel MP system for hypothermic pulsatile perfusion. After MP preservation, the contralateral kidneys were removed and the preserved kidneys heterotopically autotransplanted. Ten minutes after reperfusion, the microcirculation was reassessed. Seven days posttransplant, animals were euthanized and the kidney grafts removed for histological analysis. MP using a mean PP of 25 mmHg resulted in higher capillary blood flow after reperfusion. In the MP30 group, 6 out of 7 animals survived, whereas in the MP25 group all animals survived. Overall, improvement in recovery of renal function and a better preservation of structural integrity were seen in the MP25 group compared to the MP30 group. Using a novel system for hypothermic MP, a mean PP of 25 mmHg is preferred over a mean PP of 30 mmHg.