Gauke Kootstra

Outcome of transplantation of non-heart-beating donor kidneys.

Abstract To reduce the shortage of kidneys for transplantation, we started a non-heart-beating (NHB) donor programme, and compared the short-term and long-term outcomes of kidneys from NHB donors with those of a matched group of kidneys from heart-beating (HB) donors. 57 NHB kidneys were procured at the University Hospital in Maastricht and at three regional hospitals in the Netherlands, and were transplanted in 21 transplant centres within the Eurotransplant exchange organisation. 114 matched controls from HB donors were selected from Eurotransplant files. Mean follow-up was 85 months. At 5 years, graft survival was 54% for NHB kidneys and 55% for HB kidneys; patient survival was 75% and 77%. Kidneys from NHB donors had a significantly higher rate of delayed graft function (60% vs 35%), resulting in a longer hospital stay. Primary non-function of the graft was seen as frequently in the NHB donor-kidney group as in the HB group (14% vs 8%, p=0·3). We conclude that NHB donors are a valuable source of kidneys for transplantation.

OVERCOMING SEVERE RENAL ISCHEMIA: THE ROLE OF EX VIVO WARM PERFUSION

BACKGROUND The ability to effectively utilize kidneys damaged by severe (2 hr) warm ischemia (WI) could provide increased numbers of kidneys for transplantation. The present study was designed to examine the effect of restoring renal metabolism after severe WI insult during ex vivo warm perfusion using an acellular technology. After warm perfusion for 18 hr, kidneys were reimplanted and evaluated for graft function. METHODS Using a canine autotransplant model, kidneys were exposed to 120 min of WI. They were then either reimplanted immediately, hypothermically machine perfused (4 degrees C) for 18 hr with Belzers solution, or transitioned to 18 hr of warm perfusion (32 degrees C) with an acellular perfusate before implantation. RESULTS Warm perfused kidneys with 120 min of WI provided life-sustaining function after transplantation, whereas the control kidneys immediately reimplanted or with hypothermic machine perfusion did not. The mean peak serum creatinine in the warm perfused kidneys was 3.7 mg/dl, with the mean peak occurring on day 2 and normalizing on day 9 posttransplant. CONCLUSIONS These results indicate that 18 hr of ex vivo warm perfusion of kidneys is feasible. Furthermore, recovery of renal function during warm perfusion is demonstrated, resulting in immediate function after transplantation. The use of ex vivo warm perfusion to recover function in severe ischemically damaged kidneys could provide the basis for increasing the number of transplantable kidneys.

Hypothermia – a Limiting Factor in Using Warm Ischemically Damaged Kidneys

A study was performed to determine the limiting factors to expanding the donor pool with warm ischemically (WI) damaged kidneys. Canine kidneys were damaged by 30 min of WI, and then either cold stored (CS) in ViaSpan (4 °C) for 18 h, or warm perfused with exsanguineous metabolic support (EMS) technology (32 °C) for 18 h, or subjected to combinations of both techniques. The kidneys were autotransplanted with contralateral nephrectomy. In kidneys with WI and CS alone, the mean peak serum creatinine value was 6.3 mg/dL and took 14 days to normalize. In contrast, kidneys where renal metabolism was resuscitated ex vivo during 18 h of warm perfusion demonstrated mild elevations in the serum chemistries (2.6 mg/dL). The damage in kidneys CS for 18 h was ameliorated with 3 h of subsequent warm perfusion and eliminated by 18 h of warm perfusion. In contrast, reversing the order with CS following WI and 18 h of warm perfusion resulted in a time‐dependent increase in damage. These results identify hypothermia as a major limiting factor to expanding indications for kidney donation. While hypothermia represents the foundation of preservation in the heart‐beating donor, its use in WI damaged organs appears to represent a limiting factor.

Kidney preservation in the next millenium

For the past decades, severe hypothermia has represented the foundation of organ preservation in clinical transplantation. Beneficial as hypothermia has proven to be in preserving grafts from heart‐beating donors, hypothermia does not seem to provide the window necessary for the prospective evaluation of organ function. With the increasing use of non‐heart‐beating donors, it is logical to propose that if organs are to be evaluated prospectively, it will be necessary to preserve them at warmer temperatures. Since both glomerular and tubular functions are inhibited at temperatures below 18oC, such a goal will necessitate organ preservation at a temperature above 20oC. The principle of preservation at warmer temperatures is not new, but with future developments and approaches, successful realization appears within reach. In this overview, a brief history of previous attempts at warm preservation, in the context of the current status of kidney preservation, is presented. Future developments and approaches, with the potential for prospective testing of the function and enhanced resistance to ischemic damage, will be discussed.

Repair of Damaged Organs in Vitro

Treatments that can be performed ex vivo following ischemia to accelerate cellular recovery and ameliorate reperfusion injury could have major impact. An acellular, near‐normothermic perfusion was employed to deliver growth factors to ischemically damaged kidneys. During the treatment oxidative metabolism was sufficiently restored to support up‐regulation of cellular processes with the potential to modulate both injury and repair proteins in damaged kidneys. The results suggest that growth factor administration, without concomitant inflammation, triggers pathways for new synthesis leading to cellular recovery rather than cell death.

University Of Wisconsin Solution Is Superior To Histidine Tryptophan Ketoglutarate For Preservation Of Ischemically Damaged Kidneys

The current shortage of transplantable organs has renewed interest in kidneys obtained from non-heart-beating donors. Kidneys from these donors have suffered warm ischemia (WI). The effectiveness of two preservation solutions, i.e., the University of Wisconsin (UW) and the histidine tryptophan ketoglutarate (HTK) solutions, for preservation of kidneys that have been subjected to WI was tested in dogs. The left kidney was autotransplanted after 30 min of WI, and subsequent 24-hr cold storage (CS) in either UW (n = 6) or HTK (n = 6), with immediate contralateral nephrectomy. Surgical biopsies from the cortex were taken before WI, after 30 min of WI, after 24 hr of CS, and after 1 hr of reperfusion for electron microscopy and for analysis of energy metabolites. At 2 weeks after transplantation in the UW group, 4 out of 6 and, in the HTK group, 1 out of 6 dogs survived. As from day 2, serum creatinine was lower in the UW group as compared with the HTK group (P < 0.05). After 24 hr of CS, in the HTK group the luminal membranes of proximal tubular cells were partly denuded of microvilli. Moreover, the tubular lumen was filled with blebs and debris. In the UW group, the brush borders remained intact, although microvilli were swollen. Energy metabolites were analyzed with HPLC. Thirty minutes of WI resulted in a +/- 45% reduction of total adenine nucleotide (TAN) content. During CS, TAN levels further decreased in both groups; however, after 24 hr of CS, the levels of adenosine, inosine, hypoxanthine, and xanthine were significantly higher in the UW group as compared with the HTK group (P < 0.05, P < 0.01, P < 0.01, P < 0.01). At 1 hr of reperfusion, TAN levels were higher in the UW group as compared with the HTK group (4.66 +/- 0.16 vs. 4.02 +/- 0.28, P < 0.05). Our results show that UW is a superior solution compared with HTK in the preservation of ischemically damaged kidneys, demonstrating better survival, better recovery of kidney function, better protection against ischemia-induced ultrastructural damage, and better preservation of energy metabolism indicated by (a faster) regeneration of TAN levels after reperfusion.

Exsanguinous metabolic support perfusion--a new strategy to improve graft function after kidney transplantation.

Background. The compounding damage of warm ischemia (WI) followed by cold preservation is a major barrier in renal transplantation. Although the relative effect of WI is not yet well understood, therapeutic strategies have mostly focused on minimizing the pathology seen upon reperfusion from the cold.Our study was designed to examine the effect of restoration of renal metabolism by warm perfusion on graft survival and to investigate the compounding damage of WI. Methods. Using a known critical canine autotransplantation model (1), kidneys were exposed to 30 min WI followed by 24 hr cold storage in Viaspan. They were then either reimplanted directly or first transitioned to 3 hr of warm perfusion with an acellular perfusate before reimplantation. Contralateral kidneys were subjected to 0, 30, or 60 min WI; 24 hr cold storage, and 3 hr warm perfusion. Results. Transplanted kidneys that were warm perfused before reimplantation had both lower 24 hr posttransplant serum creatinine (median of 3.2 vs. 4.1 mg/dl) and lower peak serum creatinine (median of 4.95 vs. 7.1 mg/dl). Survival rate for warm perfused kidneys was 90% (9/10) vs. 73% (8/11). In the contralateral kidneys, metabolism was affected by the compounding damage of WI. Renal oxygen and glucose consumption diminished significantly, whereas vascular resistance and lactate dehydrogenase-release rose significantly with increasing WI. Conclusions. The results demonstrate a reduction of reperfusion damage by an acellular ex vivo restoration of renal metabolism. Furthermore, data from the contralateral kidneys substantiates the relative role of WI on metabolism in renal transplantation.

Induction of heme oxygenase-1 in kidneys during ex vivo warm perfusion

Background. Reperfusion injury plays a pivotal role in the occurrence of delayed graft function and chronic rejection. Heme oxygenase-1 (HO-1), an inducible heat shock protein, is known to have cytoprotective effects against reperfusion injury. We report on the potential for ex vivo induction of HO-1 expression during acellular warm perfusion of canine kidneys, using cobalt protoporphyrin (CoPP) as an HO-1 inducer and zinc protoporphyrin as an HO-1 inhibitor. Methods. Canine kidneys were used to evaluate HO-1 increase after exposure to warm ischemia (WI), hypothermic perfusion (mechanical perfusion [MP], 4°C), warm perfusion (exsanguineous metabolic support [EMS], 32°C), or various combinations. Results. WI alone, MP, or EMS with or without WI, had no effect on HO-1 activity. However, the presence of CoPP during EMS perfusion resulted in a significant increase in kidney HO-1 activity, whereas zinc protoporphyrin reduced HO-1 activity. The presence of CoPP during MP did not induce elevated HO-1 expression. The results of our study demonstrate that sufficient metabolism supporting new protein synthesis resulting in the expression of the protective gene, HO-1, can be accomplished during an acellular near-normothermic perfusion using CoPP. Most importantly, the time required for ex vivo HO-1 induction with this method is compatible with the current time frame for which organs are preserved clinically. Conclusions. The ability to induce HO-1 expression ex vivo eliminates the need for donor therapy to induce HO-1 increase before retrieving organs and also prevents the potential of decreasing HO-1 enzyme activity that is known to occur with temperature-mediated inhibition of oxidative metabolism during hypothermic organ storage.

Horseshoe kidney transplantation: an overview

The horseshoe kidney is the most common anatomical renal variation. It represents a fusion anomaly, mainly at the lower poles, occurring between the 4th and 6th week of gestation. Horseshoe kidneys display a great variation in origin, number and size of the vasculature. Transplantation of these deviant kidneys can be done en bloc or they can be split into two halves and transplanted into two recipients, depending on the number of vessels and the anatomy of the urinary collecting system. A literature review reveals 31 case histories, published between 1975 and 1998. Of these 21 were transplanted into 38 recipients after division and ten were implanted en bloc. Nineteen grafts (41%) showed immediate function and 21 grafts (46%) showed delayed function. Thrombosis and acute rejection, leading to non‐function was seen in six grafts (13%). The overall success rate was 87% with a mean follow‐up of 22 months. The results of horseshoe kidney transplantation are good, provided that attention is paid to certain technical details. Because of donor scarcity, horseshoe kidneys should be used for transplantation.

NOS: The Underlying Mechanism Preserving Vascular Integrity and During Ex Vivo Warm Kidney Perfusion

Research involving metabolically active and functioning organs, maintained ex vivo in culture‐like conditions, could provide numerous opportunities for medical innovations and research. We report successful perfusion of isolated canine and human kidneys ex vivo at near physiologic temperature for 48 h. During the perfusions parameters of metabolism and function remained stable. Nitric oxide synthase (NOS) was identified as the underlying mechanism preserving vascular integrity. Most importantly, when the canine kidneys were reimplanted there was immediate normal renal function. This report highlights the potential significance of whole organ culture using a warm temperature ex vivo perfusion and discusses medical applications that could be developed.