Canine kidney preservation using a new perfusate

Organ preservation solutions: linking pharmacology to survival for the donor organ pathway

PURPOSE OF REVIEW

To provide an understanding of the scientific principles, which underpinned the development of organ preservation solutions, and to bring into context new strategies and challenges for solution development against the background of changing preservation technologies and expanded criteria donor access.

RECENT FINDINGS

Improvements in organ preservation solutions continue to be made with new pharmacological approaches. New solutions have been developed for dynamic perfusion preservation and are now in clinical application. Principles defining organ preservation solution pharmacology are being applied for cold chain logistics in tissue engineering and regenerative medicine.

SUMMARY

Organ preservation solutions support the donor organ pathway. The solution compositions allow additives and pharmacological agents to be delivered direct to the target organ to mitigate preservation injury. Changing preservation strategies provide further challenges and opportunities to improve organ preservation solutions.

Mannitol infusion within 15 min of cross-clamp improves living donor kidney preservation

Background

Optical coherence tomography (OCT) revealed that cells lining proximal convoluted tubules of living donor kidneys (LDKs) procured by laparoscopic procedures were very swollen in response to the brief period of ischemia experienced between the time of arterial vessel clamping and flushing the excised kidney with cold preservation solution. Damage to the tubules as a result of this cell swelling resulted in varying degrees of acute tubular necrosis (ATN) that slowed the recovery of the donor kidneys during the first 2 weeks after their transplantation.

Methods

To prevent this cell damage during LDK procurement, we changed the protocol for intravenous administration of mannitol (i.e., 12.5 or 25 g) to the donor. Specifically, we reduced the time of mannitol administration from 30 to 15 min or less before clamping the renal artery.

Result

OCT revealed that this change in the timing of mannitol administration protected the human donor proximal tubules from normothermic-induced cell swelling. An evaluation of posttransplant recovery of renal function showed that patients treated with this modified protocol returned to normal renal function significantly faster than those treated with mannitol 30 min or more before clamping the renal artery.

Conclusion

Because slow graft recovery in the first weeks after transplantation represents a risk factor for long-term graft function and survival, we believe that this change in pretreatment protocol will improve renal transplants in patients receiving LDK.

Preservation solutions for static cold storage of kidney allografts: a systematic review and meta-analysis

Static cold storage is the most prevalent method for renal allograft preservation. Several solutions have been designed to counteract the detrimental effects of cold ischemia and reperfusion. The aim of this study was to appraise the evidence for the currently available preservation solutions. We performed a systematic literature search using MEDLINE, EMBASE, the Cochrane Library, the Transplant Library and trial registries. Inclusion criteria specified any comparative, prospective study for deceased donor renal allografts. Studies were assessed for methodological quality. The primary outcome was delayed graft function (DGF). Fifteen trials with a total of 3584 kidneys were included. Eurocollins was associated with a higher risk of DGF than University of Wisconsin solution (UW) in two randomized controlled trials (RCTs) and histidine-tryptophan-ketoglutarate (HTK) in two RCTs. UW was associated with an equal risk of DGF compared with Celsior in three RCTs and HTK in two RCTs. There was limited data regarding other comparisons and outcomes. The choice of preservation solution has an effect on the incidence of DGF, which might, in turn, affect long-term outcomes. Both UW and HTK have lower rates of DGF than Eurocollins. There is no difference in the incidence of DGF with the use of Celsior, HTK and UW. These findings are supported by registry data.

Effects of pretreatment with Yisheng injection on renal warm ischemia/reperfusion injury in mice

INTRODUCTION

Due to the organ supply shortage, the donor pool has been expanded to include non-heart-beating donors, where renal warm ischemia/reperfusion (I/R) injury is inevitable. This study was undertaken to determine whether Yisheng injection (YM) could attenuate renal warm I/R injury in mice.

MATERIALS AND METHODS

Male C57BL/6 mice were divided into sham, ischemic, and YM-treated groups using 50 minutes of left kidney ischemia. Mice were humanely killed at 4 or 24 hours postreperfusion. We assayed the effects of YM on liver functional injury, neutrophil recruitment, and proinflammatory mediators after renal I/R injury.

RESULTS

Renal I/R produced dramatic injuries in mouse kidneys. Administration of YM reduced liver function (urea nitrogen of untreated vs treated, 4.7 +/- 0.6 vs 26.6 +/- 1.5 mmol/L; P < .01) and histological injury (histological scores of untreated vs treated, 4.12 +/- 0.14 vs 0.98 +/- 0.07; P < .01). YM at doses of 5, 15, or 25 mg/kg reduced the serum levels of tumor necrosis factor-alpha (TNF-alpha) by about 32.9%, 55.1%, and 74.5%, respectively. Moreover, YM also suppressed the increase in messenger RNA (mRNA) and protein expressions of TNF-alpha and intercellular adhesion molecule-1 (ICAM-1), as well as abrogated neutrophil recruitment in a dose-dependent manner.

CONCLUSION

YM protects murine kidneys from warm I/R injury, probably via decreasing functional injury, reducing neutrophil infiltration, and suppressing the overexpression of proinflammatory mediators and adhesion molecules.

High-resolution optical coherence tomography imaging of the living kidney

Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can provide non-invasive, cross-sectional, high-resolution images of tissue morphology in situ and in real-time. In the present series of studies, we used a high-speed OCT imaging system equipped with a frequency-swept laser light source (1.3 mum wavelength) to study living kidneys in situ. Adult, male Munich-Wistar rats were anesthetized, a laparotomy was performed and the living kidneys were exposed for in situ observation. We observed the kidneys prior to, during and following exposure to renal ischemia induced by clamping the renal artery. The effects of intravenous mannitol infusion (1.0 ml of 25%) prior to and during renal ischemia were also studied. Finally, living kidneys were flushed with a renal preservation solution, excised and observed while being stored at 0-4 degrees C. Three-dimensional OCT data sets enabled visualization of the morphology of the uriniferous tubules and the renal corpuscles. When renal ischemia was induced, OCT revealed dramatic shrinkage of tubular lumens due to swelling of the lining epithelium. Three-dimensional visualization and volumetric rendering software provided an accurate evaluation of volumetric changes in tubular lumens in response to renal ischemia. Observations of kidneys flushed with a renal preservation solution and stored at 0-4 degrees C also revealed progressive and significant loss of tubular integrity over time. Intravenous infusion of mannitol solution resulted in thinning of the tubular walls and an increase in the tubular lumen diameters. Mannitol infusion also prevented the cell swelling that otherwise resulted in shrinkage of proximal tubule lumens during ischemia. We conclude that OCT represents an exciting new approach to visualize, in real-time, pathological changes in the living kidney in a non-invasive fashion. Possible clinical applications are discussed.

Warm ischemia in transplantation: search for a consensus definition

"Warm ischemia" is a term used to describe ischemia of cells and tissues under normothermic conditions. In the transplant setting, this term is used to describe two physiologically distinct periods of ischaemia: (1) Ischemia during implantation, from removal of the organ from ice until reperfusion, and (2) Ischemia during organ retrieval, from the time of cross clamping (or of asystole in non-heart-beating donors), until cold perfusion is commenced. These periods of warm ischemia differ in their nature and the magnitude of their pathophysiologic consequences. In much transplant literature, however, the term "warm ischaemia" is used to describe both of these periods indiscriminately. This paper attempts to produce a definition to distinguish between the two periods of warm ischemia.

METHODS

We conducted a questionnaire survey of all UK transplant surgeons. The definitions proposed in the survey were: (a) warm ischemia and re-warm ischemia; (b) first warm ischemia and second warm ischemia; (c) in-situ warm ischemia and ex-vivo warm ischemia; (d) warm ischemia in donor and warm ischemia in recipient; (e) no opinion or other opinion.

RESULTS

There was a 64% response rate among 134 consultants with no consensus definition being reached. The majority of consultants (31.4%) preferred the terms "warm ischemia in donor", and "warm ischemia in recipient" to distinguish the two periods.

CONCLUSIONS

This paper highlights the need to adopt uniform terms to avoid confusion between different types of warm ischemia in 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.

[Present and future of kidney transplantation]

Renal transplant is the treatment of choice for the patient with end stage renal disease. Spain is the country with the highest donation rate (33 ppm). However, at present this figure is stabilized. The development of non-beating heart programmes, living-donor nephrectomy (specially laparoscopic nephrectomy) programmes, and may be xenotransplantation in a non-immediate future could increase the transplantation activity. The knowledge of preservation mechanisms, specially with the use of perfusion machines allows to rescue for transplantation kidneys with a long warm-ischemia time. Furthermore, these machines are useful for analyzing viability markers. The new immunosuppressive drugs: Tacrolimus, Mycophenolate-Mophetil, Rapamycin and monoclonal antibodies against alpha chain of the interleukine-2 receptor (Basoliximab and Dazcizumab) have reduced the incidence of acute rejection in the immediate renal transplant period. However, its effect in the long-term follow-up period is still a matter of controversy. The incidence of tumour in the renal transplant recipient is increased, specially those of lymphoma, skin cancer and Kaposi sarcoma. Periodical exams for detecting the development of tumours are mandatory in this population. Finally, xenotransplantation is an attractive alternative, although immunological, infective and ethical barriers should previously be resolved.

Reduced lipid peroxidation and ischemia-reperfusion injury after lung transplantation using low-potassium dextran solution for lung preservation

Ischemia-reperfusion injury is one of the significant problems in clinical lung transplantation. We investigated the effect of lung preservation with Euro-Collins solution (EC group) or low-potassium dextran solution (LPD group) on lipid peroxidation and ischemia-reperfusion injury in a pig model of lung allotransplantation. The donor lungs were preserved at 4 degrees C for 18 h. Left-sided single lung transplantation was performed, followed by 6 h of reperfusion. Lipid peroxidation was measured as thiobarbituric acid-reactive materials (TBARM) in bronchoalveolar lavage (BAL) fluid and effluent solutions from pulmonary artery (Effluent). After 18 h of ischemia, the LPD group showed lower TBARM in BAL and Effluent than the EC group (p < 0.05). After ischemia plus reperfusion, lung wetto-dry weight ratios and TBARM levels in BAL in the LPD group were lower than those of the EC group (p < 0.05). Lung wet-to-dry weight ratios correlated with TBARM levels in BAL (p < 0.05, r = 0.50). We conclude lipid peroxidation in BAL and Effluent may reflect the degree of ischemia-reperfusion injury, and lung preservation with LPD can reduce lipid peroxidation and lung injury as compared with EC.

Adverse effect of donor vasopressor support on immediate and one-year kidney allograft function

BACKGROUND

This purpose of this study was to determine if there was a significant difference between the rates of acute tubular necrosis (ATN) and long-term graft survival in renal allografts procured from donors requiring inotropic support (DRIS) and those from donors not requiring inotropic support.

METHODS

Eighty-two consecutive cadaveric renal transplant patients were prospectively followed in our local procurement area, the Delaware Valley Transplant Program. Forty-eight patients received organs from DRIS (> 10 mcg/kg per minute of dopamine, dobutamine, epinephrine, and norepinephrine alone or in combination), and 34 did not.

RESULTS

Allografts from the non-DRIS group had an immediate function rate of 82.4% and a 1-year function rate of 91.2%. In comparison, the DRIS grafts had an immediate function rate of 58.3% and a 1-year function rate of 72.9%. These differences were statistically significant. The mean serum creatinine in the non-DRIS group was 1.46 +/- 0.58 mg/dl, whereas in the DRIS cohort it was 1.89 +/- 0.93 mg/dl.

CONCLUSIONS

Kidneys transplanted from DRIS had significantly (1) poorer immediate function, (2) worse 1-year survival rates, and (3) higher serum creatinine at 1 year. We conclude that recipients receiving organs from donors requiring inotropic support are at a higher risk of developing ATN after surgery and experience reduced 1-year function.

Preservation of bone graft vascularity with the University of Wisconsin cold storage solution

The preservation of the microcirculation of bone has been evaluated with use of an in vitro canine tibia perfusion model. The production of relaxing factors by the osseous vascular endothelium was used as a metabolic marker for viability. This endothelial eccrine function was preserved for 5 days (120 h) by cold storage without continuous perfusion after a washout with the University of Wisconsin (UW) solution. This synthetic perfusate was superior to Krebs Ringer solution (p < 0.05), but storage without perfusion failed to prevent a significant rise in vascular resistance. Two techniques were effective for the preservation of bone vascularity for 24 h: washout with UW solution followed by nonperfusion cold (4 degrees C) storage, and vascular washout with mannitol solution followed by continuous hypothermic (5 degrees C) microperfusion (0.03 ml/min) with UW solution. The most consistent, and lowest, vascular resistance was produced by the microperfusion technique. However, UW solution does not consistently prevent an increase in vascular resistance with hypothermic ischemia. This technique may prove useful for the preservation of vascularized bone grafts, but it needs to be evaluated in a transplantation model.

Safe pulmonary preservation for 12 hours with low-potassium-dextran solution

The function of porcine left lung allografts was studied after perfusion with (150 mL/kg) and storage for 12 hours in a 4 degrees to 6 degrees C low-potassium-dextran solution (Perfadex; Kabi Pharmacia AB, Uppsala, Sweden). After a left lung transplantation, an artificial lung in the form of venoarterial extracorporeal membrane oxygenation was established. The artificial lung has a "biological" heparin-coated surface (Carmeda AB, Stockholm, Sweden), and there is no need for systemic anticoagulation. Immediately thereafter, pneumonectomy of the normal right lung was done. All the animals were weaned from the artificial lung within 1 hour after the pneumonectomy. Six animals were followed up for 24 hours. They were in good condition throughout the 24-hour observation period with arterial oxygen tensions around 200 mm Hg (inspired oxygen fraction = 0.4) and arterial carbon dioxide tensions around 40 mm Hg. This study demonstrates a reliable method for continuous evaluation of the function of a transplanted lung immediately after transplantation and over the ensuing postoperative period. Safe 12-hour lung preservation can be obtained with the low-potassium-dextran solution Perfadex.

Improvement of renal preservation by adding lidoflazine to University of Wisconsin solution. An experimental study in the rat

The purpose of this study was to investigate the possibility of improving the organ preservation properties of the University of Wisconsin (UW) solution by adding the calcium entry blocker lidoflazine. We also investigated the possibility of decreasing the cold ischemia and reperfusion damage by pretreatment with lidoflazine of the donor and/or recipient. The protective effects of lidoflazine treatment were estimated by measuring the amount of trapped erythrocytes in the rat renal medulla after 48 h of cold storage, subsequent transplantation, and 20 min of reperfusion. Lidoflazine (20 mg/liter) added to the UW solution decreased the amount of erythrocyte trapping from 14.8 +/- 3.1% in controls to 8.6 +/- 1.7% (P less than 0.01). The flow rate of the flush-out solution during the harvesting procedure was also significantly (P less than 0.01) increased when lidoflazine was included in the UW solution (1.10 +/- 0.21 ml/min vs 0.75 +/- 0.22 ml/min). Administration of lidoflazine (0.28 mg/kg body wt) to the donor and/or the recipient did not further reduce the postischemia/reperfusion damage as estimated by the degree of erythrocyte trapping. In conclusion, the results indicate that the preservation properties of the UW solution can be significantly improved by adding lidoflazine to the solution.

Effect of prostacycline analogue OP-41483 and perfusate on liver preservation by simple hypothermia in rats

Changes in rat livers preserved by simple cooling immersion in modified Sacks' solution, Ross' solution and Ross' solution with OP-41483, a PGI2 analogue, were compared after 12, 24, 36, and 48 hours. The viability of the preserved livers was assessed by measuring the tissue ATP concentrations and quantifying morphologic changes in the mitochondria observed by transmission electron microscopy using a 4-point scale, the mitochondrial score. A general trend towards progressive mitochondrial degeneration was observed in all groups. After 12 hrs of preservation, there was no significant difference between the groups. From 24 to 48 hours, the mitochondrial scores for livers preserved with OP-41483 were significantly higher than in the two other groups. No difference among the groups in tissue ATP concentration was observed at any time. Thus, OP-41483 was considered to retard mitochondrial degeneration in liver preservation by simple hypothermic immersion and does so by a mechanism not directly related to intracellular energy stores. The possibility that OP-41483 acts by stabilizing the lysosomal membrane is discussed.

Effect of sugars in the preservation solution on liver storage in rats

We have performed 128 rat liver transplants in order to examine the effect of sugars in preservation solutions on cold storage of rat livers. Glucose (Mw. 180), sucrose (Mw. 348), and raffinose (Mw. 594) were tested. Rat livers were preserved at 4 degrees C for 12, 16, 18, and 24 h in standard Eurocollins solution (EC solution) (solution A) or in one of three modified EC solutions in which 194 mM/liter glucose in standard EC solution was replaced by 140 mM/liter of glucose (solution B), sucrose (solution C), or raffinose (solution D). The osmolarity of the modified solutions (solution B-D) was 320 mOsm/liter. Using standard EC solution (solution A), the 1-week survival rate of rats receiving livers preserved for 12, 16, 18, or 24 h was 6/8, 4/8, 1/8, and 0/4, respectively. With solution B, in which 194 mM/liter glucose was replaced by 140 mM/liter glucose, 1 week survivors following transplantation of livers preserved for 12, 16, 18 or 24 h were 4/8, 3/8, 2/8 and 0/4, respectively. Solution C, which was identical to solution A except for the replacement of 194 mM/liter glucose by 140 mM/liter sucrose, gave the following 1-week survival rates: 5/8 for 12 h, 5/8 for 16 h, 2/8 for 18 h, and 0/4 for 24 hours preservation, respectively. Using solution D, which differed from A in the replacement of glucose by 140 mM/liter raffinose, the 1-week survival rates of rats grafted with livers preserved for 12, 16, 18, and 24 h were 6/8, 5/8, 3/8 and 0/4, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved renal transplant preservation using a modified intracellular flush solution (PB-2). Characterization of mechanisms by renal clearance, high performance liquid chromatography, phosphorus-31 magnetic resonance spectroscopy, and electron microscopy studies

A number of new intracellular renal flush solutions have been found to be more efficacious than Collins-2 (C-2) solution in extending organ viability during simple cold storage. However, the mechanism of action of these solutions remains poorly understood. To delineate better underlying intracellular mechanisms, we studied a modified, simple, hypothermic, intracellular (340 mOsm/kg) flush solution (PB-2). The development of PB-2 solution is based on the ability of some of its individual components to minimize ischemic adenine nucleotide (AN) catabolism and endothelial post "reperfusion injury." Preliminary results in 10 canine autorenal transplants show a significant (P less than 0.02) improvement in renal recovery and viability (recipient posttransplant inulin clearance and survival) after 50 h of cold storage compared with 10 canine kidneys similarly preserved using conventional C-2 flush solution. High performance liquid chromotography (HPLC) studies show a significant (P less than 0.01) loss of AN using C-2, while PB-2 was associated with regeneration of AN within 45 min of reperfusion. Magnetic resonance spectroscopy using phosphorus 31 (31P-MRS) showed more high energy phosphorus metabolites (phosphomonoester and nicotinamide-adenine-dinucleotide phosphate: P less than 0.001) at 50 h cold storage using PB-2 compared with C-2. Electron micrographs (EM) revealed normal microcapillary morphology for the PB-2 group; however, moderate vascular red and white blood cell clumping was observed in the C-2 group. Characterization of the basic preservation mechanisms by HPLC, 31P-MRS, and EM studies indicates that PB-2 solution enhances renal preservation by diminution of both reperfusion injury and the loss of intracellular high energy metabolites that are necessary for viability.

The influence of hypoxic cell-free perfusion and ischemia on cell morphology in the proximal tubular S2-segment of the rat kidney

In the present study, in-situ perfused rat kidneys were used as a model to demonstrate the different morphological changes induced by various periods of warm ischemia or of warm hypoxic cell-free perfusion. Light and electron microscopic evaluation revealed no changes in the S2 proximal tubular cells after short exposure times of up to 4 min, whereas longer periods resulted in changes ranging from slight alterations (at 10 min) to severe damage (at 60 min). Warm hypoxic cell-free perfusion induced obvious alterations in the proximal tubular cells somewhat sooner than warm ischemia. The microscopical findings were consistent with the statistics of a detailed morphometrical analysis performed on the mitochondrial diameter. The results were further substantiated by counting intramitochondrial electron-dense condensations ('flocculent densities') as indicators of irreversible cell alteration.

Acute and subacute effects of injury on the canine alveolar septum

The effect of papain on the prevalence and distribution of alveolar macrophages, alveolar septal interstitial tissue gaps and epithelial cells in normal canine pulmonary alveoli was studied by light and electron microscopy. Serial sections of whole alveoli from control animals and from animals sacrificed 4 h, two weeks and one month after the instillation into one lung of crude papain in saline solution containing India ink as a marker were compared. In dogs, as in humans, there is normally a zonal distribution of alveolar macrophages and type 2 cells at alveolar junctional sites. We hypothesize that early alveolar septal injury takes place at these junctional sites, judging from concentration of alveolar macrophages and interstitial septal gaps at these sites following papain exposure, and also that septal repair activities are greatest at these sites, in view of the preponderance and high prevalence of type 2 cells occupying interstitial septal gaps in junctional zones. Consequently, the type 2 cell may play a role beyond that of merely replacing type 1 epithelial cells following alveolar septal injury.

Hypothermic preservation of rabbit kidneys for 48 hours using low ionic strength solutions

Microwaves offer the prospect of rapid and uniform heating of frozen organs. This is significant in the context of cryopreservation, and particularly of vitrification, because microwave heating may help to avoid crystallization or recrystallization of ice during warming, minimize any effects of high cell density, and reduce thermal-mechanical stresses. Previous work has established a rationale for reducing the ionic strength of solutions used to prepare tissues for microwave heating, since this permits the use of lower frequencies, which makes heating more uniform, without increasing the risk of thermal runaway (T. P. Marsland, S. Evans, and D. E. Pegg, Cryobiology 24, 311-323, 1987). In this paper we report a study of two possible low ionic strength perfusates, in rabbit kidneys, using 48 hr of hypothermic storage and autotransplantation as the test system. This model was chosen because there is a great deal of basic information about it. Both a single-pass "flush" preservation solution and a solution designed for continuous perfusion gave excellent results. The continuous perfusion system, which would be the more suitable for introducing cryoprotectants, gave five of five surviving animals with peak serum creatinine levels of 353-555 mumol/liter normal histology in three cases, and only very minor damage in the other two. There would therefore seem to be no obstacle to the use of perfusates having a low ionic strength in renal cryopreservations studies.

Lung transplantation

The supply of donor organs remains extremely limited, and improved methods of maintaining the lungs of potential donors to allow for transplantation must be developed. Currently the upper limit of donor lung ischemic even with our "best" preservation techniques is approximately 4 to 6 hours. Improved methods for preservation will increase the supply of suitable lungs and will considerably simplify the logistics of transplantation just as has occurred with liver transplantation. Efficient use of donor organs remains of paramount importance. We recently performed two single-lung transplants utilizing lungs from one donor. Likewise, there is no reason why a lung could not be sent to another center for transplantation if the harvesting group uses only one lung. Sufficient progress has been achieved to date to warrant continued application of lung transplantation for end-stage pulmonary disease. With increasing experience, one can anticipate refinement of techniques and broader application of these procedures. Single lung transplantation, initially restricted to patients with end-stage pulmonary fibrosis, has now been successfully applied to patients with emphysema, pulmonary hypertension, and other conditions. Although transplantation currently can offer real benefit only to a limited number of persons, it serves to create hope for many others. An additional benefit may prove to be the interest and attention that transplantation focuses on patients with end-stage lung disease and on the pathophysiology of chronic respiratory failure. Knowledge gained may ultimately result in the prevention of many of the disorders for which lung transplantation currently offers the only hope.

Influence of different preservation solutions and intentional hemodilution of recipient on viability of preserved and transplanted rat kidneys

A total of 81 rat kidney grafts, flushed out and cold stored in either Sacks' or University of Wisconsin (UW) solution, were transplanted into hemodiluted (Hct = 30% +/- 4%) or untreated (Hct = 43% +/- 3%) recipients. The cold ischemia times (CIT) used were 24 and 36 h. One week after transplantation, the surviving recipients (n = 67) were contralaterally nephrectomized. The experiment was terminated after a total period of 4 weeks, and the percentage of surviving animals was determined for each treatment. Data was pooled and the results show that grafts cold stored in UW solution were viable to a significantly greater extent and after longer CIT than grafts cold stored in Sacks' solution (47% vs 23%; P less than 0.05). Recipient hemodilution did not improve graft viability (39% vs 32%; NS). Kidneys cold stored for 24 h were viable to a greater extent than kidneys with a CIT of 36 h (50% vs 15%; P less than 0.01).

Organ flush out solutions and cold storage preservation solutions: effect on organ cooling and post ischemic erythrocyte trapping in kidney grafts. An experimental study in the rat

Three flush out and cold storage solutions were tested for flow rate during flush out, ability to decrease organ temperature, degree of tissue edema and degree of preservation damage of the kidney as measured by the amount of post transplantation erythrocyte trapping in the renal medulla. The solutions tested were a modification of a new perfusion solution (University of Wisconsin; mUW), a standard preservation solution (Sacks') and an extracellular histidine solution (Frödin-Wolgast; FW). The flow rate was significantly higher for FW compared to mUW and Sacks' and consequently a more rapid decrease of organ temperature was achieved. The results also show that edema formation as well as the amount of erythrocyte trapping was lower in kidneys stored in mUW, indicating that mUW is better cold storage solution than Sacks' or FW.

Ultrastructural changes in rat liver sinusoids during storage in cold Euro-Collins solution

Changes in the sinusoids of rat livers stored in cold (2 degrees C) Euro-Collins solution for various periods were observed using combined scanning (SEM) and transmission electron microscopy (TEM). The sinusoidal endothelial cells were vulnerable to cold ischemia. Fenestrations of the endothelial cells were enlarged and became mesh-like after a 4-h preservation period. Following 8 h storage the sieve plates and cytoplasmic processes of the endothelial cells were destroyed and there was a tendency for the perikaryon to desquamate. Blebs derived from hepatocytes were seen after 4 h and these increased in number and size with prolonged preservation. Although the sinusoids were filled with blebs after 24 h preservation. no irreversible ultrastructural damage in the parenchymal cells was observed. Within 12 h storage, the liver had a mosaic pattern after perfusion fixation indicating uneven fixation and profound circulatory disturbance. These results suggest that endothelial cell destruction and/or numerous blebs may have unfavorable effects on the microcirculation of the transplanted liver after prolonged preservation.

Effect of cooling on the intracellular concentrations of Na+, K+ and Cl- in cultured human endothelial cells

Cooling is accepted as a practical way of lowering cell metabolism in vein grafts during coronary by-pass surgery. We have previously shown that low temperature causes endothelial cells to become detached, both in in vitro and in vein graft. In this study we have looked at the effect of cold on the concentrations of intra- and extracellular electrolytes. Human endothelial cells were grown on titanium grids for electron microscopy. The cells were incubated for 30 min at 37 degrees, 20 degrees, and 4 degrees C with cell culture medium containing human serum, and at 20 degrees and 4 degrees C with heparinized sodium acetate solution with serum, frequently used for flushing and distending vein grafts. Freeze-dried cells were then subjected to elemental X-ray microanalysis. The ambient fluid was analysed by flame photometry. At 20 degrees and 4 degrees C, intracellular concentration of sodium increased, and potassium decreased, compared with controls (37 degrees C). The changes in sodium concentrations were aggravated when cell culture medium was replaced by heparinized sodium acetate. The intracellular chloride concentration did not change when cells were stored in cold cell culture medium. The extracellular concentration of potassium increased with increasing incubation time at 4 degrees C. The connection between these findings and cell detachment is discussed.

Effects of cold ischemia and reperfusion on trapping of erythrocytes in the rat kidney

After reperfusion of kidneys subjected to a period of warm ischemia, the medulla displays a vascular congestion of erythrocytes, especially in the inner stripe of the outer zone, a phenomenon referred to as "trapping." This trapping causes reflow alterations, thus contributing to postperfusion medullary ischemia. The purpose of the present investigation was to study whether trapping also occurs after reperfusion of kidneys following varying periods of cold ischemia and to determine if there is any correlation between the degree of cold ischemic injury and the extent of erythrocyte trapping. Rat kidneys stored at +4 degrees C for 0-30 h were transplanted into recipient animals pretreated with a 51Cr-labelled erythrocyte suspension. Twenty minutes after reperfusion, the grafts were removed and microdissected into cortex, outer and inner stripes of the outer medullary zone, and inner zone, respectively. The radioactivity of these specimens was measured, and the erythrocyte content for each specimen was calculated. The results show a maximal trapping for cold ischemia time (CIT) of about 12-15 h. A linear correlation between the amount of trapping and CIT could be found in all parts of the kidney (except for the cortex) for CIT 0-15 h. The best correlation was found in the part where the trapping was most prominent, i.e., in the inner stripe. After CIT of 15 h or more, no correlation could be found. It is suggested, as described in models of warm ischemia, that the obstructions of the capillaries by trapped erythrocytes following reperfusion is of pathophysiological significance for the development of post-transplant acute renal failure.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of solutions for lung preservation using pulmonary alveolar type II cell viability

Many special solutions have been developed to protect the ischemic lung in preparation for transplantation. To determine an effective solution, we isolated pulmonary alveolar type II cells from rat lungs. These cells play an important role in sodium transport and the production of surfactant; thus, they are crucial to the respiratory physiology of the lung. In this study, we examined in vitro the effect of various solutions such as Collins' solution, Collins-Sacks solution, and glucose-insulin-potassium solution on alveolar type II cell viability. The cell viability was examined with a trypan blue dye exclusion test and [3H]thymidine uptake proliferation assay after 24 and 72 hours of incubation. The alveolar type II cells in the glucose-insulin-potassium solution had greater viability compared with cells cultured in either Collins' or Collins-Sacks solution. This study demonstrates that glucose-insulin-potassium solution has the least toxic effect on isolated alveolar type II cells compared with other preserving solutions.

A model for thermal gradients during renal vascular anastomoses

Quantitative knowledge of warm ischemic intervals is of special importance in organ transplantation. Warm ischemia as a function of time is deleterious to tissue survival. In a laboratory model of a preserved transplantable organ, we determined thermal gradients in pig kidneys similar in size to human kidneys. Sixteen nonviable porcine kidneys cooled to 0 degrees C were placed in an artificial "iliac fossa." The posterior renal wall was in contact with the normothermic fossa. The anterior renal wall was exposed to the ambient temperature of the "operating room." The temperature of both walls was monitored for a minimum of 2 hr. Temperature changes relative to time and kidney weight were studied. The temperature of the posterior wall rises above 20 degrees C within 5 to 10 min; the anterior wall attains this temperature within 30 to 40 min. The thermal gradient between the two walls is significantly greater for larger kidneys (200 g) than for smaller kidneys (100 g). Implications for biochemical pathology are discussed.

Effects of glucose in protected ischemic kidneys

Energy reserves (TAN) and anaerobic substrates (glucose, glycogen) are lower in renal than in myocardial tissue. Euro-Collins-solution contains nearly 200 mmol/l glucose, while the HTK-solution of Bretschneider contains none. Therefore the influence of glucose on kidney lactate production, on energy reserves (TAN), intrarenal pH and on morphology during the protection of ischemic kidneys was analysed using either Euro-Collins-solution, or modified "Euro-Collins-solution", containing mannitol instead of glucose, or HTK-solution with and without the addition of 5, 10 and 20 mmol/l glucose. Glucose content changed during kidney perfusion with Euro-Collins-solution from about 60 to 800 mumol/gdw. While intrarenal pH decreased from 7.1 to 5.1 in Euro-Collins-kidneys during 420 min of ischemia at 25 degrees C, pH decreased to 6.7 with the modified, mannitol containing "Euro-Collins-solution". In HTK-protected kidneys intrarenal pH decreased with increasing glucose addition to the solution. Although Total Adenine Nucleotides are highest at the end of ischemia with Euro-Collins-solution, structural protection after the same ischemic stress was best in HTK-protected kidneys without glucose addition. We conclude that glucose stimulated lactate production, reduced interstitial pH in the kidney even in combination with a highly buffered solution and that it might cause greater membrane permeability leading to a structural deterioration. Mannitol seemed more appropriate than glucose in this respect, although other substances, which provide energy substrate and prevent structural damage, may exist.

Post-ischemic renal function after kidney protection with the HTK-solution of Bretschneider

The cardioplegic solution HTK of Bretschneider was used for canine kidney protection. The kidneys were perfused with this solution for 6-10 min prior to the induction of ischemia. The kidneys were left in-situ for 60, 90, 120 and 135 min ischemia time at a temperature of 25-34 degrees C (n = 13). As a control group we used unilateral nephrectomized dogs (n = 9). After unilateral nephrectomy an elevated plasma creatinine in comparison to preoperative values was observed. After 60 and 90 min under HTK-protection the postoperative plasma creatinine was not elevated compared to the control group. After 120 min of ischemia creatinine level was slightly increased to an average of 2.1 mg% on the first and second postoperative day. These experiments indicate the protective effect of the cardioplegic solution for canine kidney preservation in situ.

Optimization of a vehicle solution for the introduction and removal of glycerol with rabbit kidneys

Previous studies with rabbit kidneys in our laboratories have used a plasma-like solution as the vehicle for the introduction and removal of glycerol. Other workers have usually employed high-potassium solutions. In this study we have assayed the function of rabbit renal cortical slices after incubation in a range of solutions, each of which contained 1 M glycerol, for 4 hr, followed by stepwise removal of the cryoprotectant. The functions measured were endogenous oxygen consumption, p-aminohippurate uptake, and the ability of the slices to accumulate potassium. Exposure to glycerol produced a considerable reduction of slice function, but, in the presence of glycerol, elevation of the potassium concentration was beneficial, whereas high concentrations of magnesium were detrimental. The optimum potassium concentration was 70-100 mM. Replacement of chloride by a range of anions of higher molecular weight was either without benefit (glycerophosphate) or detrimental (sulfate, citrate, and gluconate). Elevation of total osmolality from 300 to 400 mosmolal with glucose, mannitol, glycerophosphate, or Pipes reduced slice function, but when the same osmolality was achieved by raising the concentration of all the components of the solution in the same ratio, there was no significant loss of function. There was a weak optimum pH at ca. 7.0. These experiments led to the formulation of a bicarbonate-buffered perfusate containing 80 mM potassium and 17.5 g Haemaccel per liter, having a pH of 7.0 with 5% CO2 at 10 degrees C, and an osmolality of 400 mosmol/kg. This solution was used to preserve rabbit kidneys for 20 hr at 10 degrees C, by continuous perfusion, and was compared with our previous Haemaccel perfusate, HP5, which contained 4 mM K+, 111 mM mannitol, and had a pH of 7.4. The two solutions were equally effective.