Preservation Of Human Kidneys Research Articles

A cell-free nutrient-supplemented perfusate allows four-day ex vivo metabolic preservation of human kidneys

The growing disparity between the demand for transplants and the available donor supply, coupled with an aging donor population and increasing prevalence of chronic diseases, highlights the urgent need for the development of platforms enabling reconditioning, repair, and regeneration of deceased donor organs. This necessitates the ability to preserve metabolically active kidneys ex vivo for days. However, current kidney normothermic machine perfusion (NMP) approaches allow metabolic preservation only for hours. Here we show that human kidneys discarded for transplantation can be preserved in a metabolically active state up to 4 days when perfused with a cell-free perfusate supplemented with TCA cycle intermediates at subnormothermia (25 °C). Using spatially resolved isotope tracing we demonstrate preserved metabolic fluxes in the kidney microenvironment up to Day 4 of perfusion. Beyond Day 4, significant changes were observed in renal cell populations through spatial lipidomics, and increases in injury markers such as LDH, NGAL and oxidized lipids. Finally, we demonstrate that perfused kidneys maintain functional parameters up to Day 4. Collectively, these findings provide evidence that this approach enables metabolic and functional preservation of human kidneys over multiple days, establishing a solid foundation for future clinical investigations.

Role of fibrinogen in the glomerular permeability of the perfused, isolated dog kidney

A technique commonly used in the preservation of human kidneys awaiting transplantation is pulsatile perfusion with a solution that contains a commercially derived protein fraction obtained from human plasma [1]. It has been shown that perfusion of dog kidneys with such a solution results in the appearance of considerable amounts of protein in the urine [2, 31. On investigation, it was observed that the protein component of the perfusate consisted of albumin, and alpha 1 and 2 globulins, but did not contain any fibrinogen or gamma globulin. Preliminary studies revealed that when fibrinogen was added to the perfusate, the proteinuria appeared to diminish. The fact that this was associated with an increase in glomerular filtration rate (GFR) lead us to examine more closely the mechanism by which fibrinogen exerts its effect, on the assumption that such a study might contribute to an understanding of the mechanism by which proteins normally are prevented from passing from the plasma into the glomerular filtrate. As well, the effect of fibrinogen on the functional integrity of kidneys which are to be used for transplantation was of additional interest. The human plasma fraction used in the perfusion fluid was either obtained commercially (Cutter Diagnostics, Missisauga, Ontario, Canada) or was prepared from plasma obtained from patients undergoing plasmapheresis. Fifty milliliters (200,000 KIU/ml) of the plasmin inhibitor Trasylol were added to each liter of this plasma. The plasma was then incubated for 1 hr at room temperature with 90 g of solid barium sulphate and 5.3 g of magnesium sulphate to absorb the thrombin [41. Following centrifugation, the absorption step was repeated on the supernatant twice more. A 50% solution of polyethylene glycol (PEG 6000) was then added to the supernatant to make it 10% weight per volume with respect to PEG, and the precipitate was removed by centrifugation at x l0,000g for 30 mm at room temperature. (The PEG was utilized to precipitate albumin, alpha I and alpha 2 globulin.) The pH of the supernatant was adjusted to 5.0 with 0.1 N HC1 and the precipitate (plasmonate) was dissolved in 0.45 M sodium acetate buffer, pH 7.0, containing 85 mmoles sodium chloride and 40 mm acetyltryptophan, to give a protein concentration of 4.5 g/dl. To this solution was added 2.5 g dextrose, 250,000 U of potassium penicillin 0, 62.5 mg of methylprednisolone, 2,500 U heparin, 149 mg potassium

TIME COURSE OF GLOMERULAR ENDOTHELIAL INJURY RELATED TO PULSATILE PERFUSION PRESERVATION

To elucidate the time course of glomerular and arterial endothelial injury resulting from pulsatile perfusion preservation of human kidneys, we examined two kidneys, one at 16 and the other at 42 hr, for which no suitable recipient could be found. The scanning electron microscope revealed subtle changes at 16 hr in the filtration barrier. These included mild endothelial swelling with an increase in the appearance of bulbous processes, and elongated fenestrae. The visceral epithelial surface was normal as was the arterial endothelial surface. By 42 hr the glomerular endothelial surface displayed very prominent cytoplasmic ridges and clearly distorted fenestrae. The arterial endothelium exhibited a tendency to separate from the vessel wall. The proximal tubular epithelium revealed scattered loss of microvilli. These changes are similar in kind to, albeit less severe than, those described after 60 hr of perfusion. They may represent cell swelling following ischemia, or be the result of altered cell permeability engendered by low temperature. The possibility remains that such changes could be minimized by modifying the perfusate. Scanning electron microscopy provides a versatile tool in the study of vascular and other surfaces of tissues stored with perfusion preservation.

Prolonged Human Kidney Preservation by Intracellular Electrolyte Flush Followed by Cold Storage

No kidney transplant center responding to a kidney preservation questionnaire would accept a kidney flushed with an intracellular electrolyte solution and cold-stored for over 40 hours. This study from one center is a comparison of 50 primary cadaver kidney grafts preserved with an intracellular electrolyte flush followed by cold storage for 40 to 61 hours to 82 primary cadaver kidney grafts preserved by the same method for 9 to 24 hours. Kidneys cold-stored for over 40 hours had a significantly increased requirement for dialysis in the 1st week following transplantation (82% versus 34%) and a significantly increased 1-month serum creatinine nadir (2.3 mg/dL versus 1.7 mg/dL). Actuarial graft survivals and serum creatinine levels at 1, 2, and 3 years after grafting were not significantly different. Cadaver donor methylprednisolone (30 to 60 mg/kg) two to nine hours prior to kidney removal significantly reduced the requirement for 1st-week hemodialysis in the kidneys cold-stored for over 40 hours (60% versus 91%). Kidneys preserved by flushing with cold intracellular electrolyte solution can be successfully transplanted after over 40 hours of simple cold storage when the warm ischemia time is very short.

Human Kidney Preservation Using Machine Perfusion Followed by Intracellular Electrolyte Flushing

Transplant centers that do not have pulsatile machine perfusion capabilities are reluctant to accept kidneys from programs that do. Four human kidneys were retrieved by other centers, initially placed on pulsatile machine perfusion pumps for 13 to 28 hours, removed from the pumps, flushed with intracellular electrolyte solutions and cold-stored for 13 to 36 hours before transplantation at our institution. All recipients required dialysis during the first week after transplantation. The 1-month serum creatinine nadir was 2.2 plus or minus 1.1mg. per dl., and all kidney grafts were functioning 3 months after transplantation. Pulsatile machine perfusion followed by ice-cold intracellular electrolyte flushing and simple cold storage can provide satisfactory renal function when the warm ischemia time is short.

Successful Human Kidney Preservation by Intracellular Electrolyte Flush Followed by Cold Storage for More Than 48 Hours

Transplantation of cadaver kidneys after flushing with an ice-cold intracellular electrolyte solution is inhibited by arbitrary time limits on cold ischemia. During the 25-month interval ending March 22, 1982 we transplanted 7 kidneys preserved by this method and cold-stored for 48.2 to 61.4 hours. Of the recipients 86 per cent required dialysis within 1 week after transplantation, the mean serum creatinine nadir within 1 month was 2.1mg./dl. and the graft survival at 1 month was 71 per cent. The 1-year actuarial cadaver graft survival was 69.2 plus or minus 18.1 per cent. Kidneys preserved by this simple method can be transplanted successfully after 48 hours of simple cold storage.

Human kidney preservation by intracellular electrolyte flush followed by cold storage for over 24 hours.

Many transplant teams are reluctant to accept kidneys preserved with intracellular electrolyte flushing followed by simple cold storage when preservation time exceeds 24 hr. This study from one center is a comparison of 63 primary cadaver kidney grafts preserved with Collins 2 solution flush followed by cold storage for 9 to 23 1/2 hr to 42 primary cadaver kidney grafts preserved by the same method for 24 to 44 1/2 hr. Kidneys cold-stored for over 24 hr had a significantly increased requirement for dialysis in the first week following transplantation (55% versus 30%). One-month serum creatinine nadirs and actuarial graft survivals were not significantly different. Cadaver donor methylprednisolone (30 to 60 mg/kg) 2 to 9 hr prior to kidney removal reduced the requirement for first-week hemodialysis in the kidneys cold-stored for over 24 hr (23% versus 69%, P under 0.05). A human kidney preserved by the same method and cold-stored for 61 hr was successfully transplanted into a 38-year-old myelodysplastic. Satisfactory human kidney preservation can occur with intracellular electrolyte flush solutions followed by cold storage for over 24 hr when the warm ischemia time is very short.

Comparison of Intracellular Flushing and Cold Storage to Machine Perfusion for Human Kidney Preservation

Transplant teams have been reluctant to accept kidneys preserved with intracellular electrolyte flushing followed by simple cold storage, especially when retrieved by non-transplant surgeons or when preservation time exceeds 24 hours. This study from 1 center is a comparison of 40 primary cadaver kidney grafts preserved with Collins’ C2 flushing followed by simple cold storage to 37 primary cadaver kidney grafts preserved with cryoprecipitated plasma on the MOX-100 machine. Cold storage time was 10 to 44.5 hours in the C2 group and 3.5 to 39 hours in the machine-perfused group, with a mean of 23 hours in each group. There was no significant difference between the 2 preservation methods no matter who removed the kidney with respect to 1) the incidence of acute tubular necrosis, 2) the 1-month serum creatinine nadir of surviving grafts and 3) the actuarial graft survivals up to 2 years. Among the 40 C2-preserved kidneys 17 were retrieved by community surgeons and 23 were retrieved by transplant surgeons. Human kidneys removed from beating-heart cadaver donors can be preserved satisfactorily with either Collins’ 2 flushing followed by simple cold storage or pulsatile machine perfusion, even when preservation times exceed 24 hours.

Human Kidney Preservation by Flushing With Intracellular Solution and Cold Storage

Simple flushing and cold storage of human kidneys for transplantation has not been accepted for preservation times exceeding 24 hours. A prospective study of 25 primary cadaver kidney transplants was performed to evaluate Collins C2 solution for human kidney preservation. Cold storage time was 10 to 23 hours in 14 cases and 26 to 44.5 hours in 11 cases. Seventeen (68%) of the kidneys had immediate, sustained function. The one-month function rate was 88%. There were no significant differences between the 10- to 23-hour and the 26- to 44.5-hour groups with respect to the incidence of first-week dialysis, one-month graft function, or mean lowest serum creatinine value. Human kidney preservation time can be safely extended beyond 24 hours with Collins C2 flushing followed by simple cold storage.

Preservation of human kidneys for transplantation: Preliminary results with a Gambro perfusion machine

Preservation of human kidneys for transplantation: Preliminary results with a Gambro perfusion machine

Preservation of Human Kidneys for Transplantation: Preliminary Results with a Gambro Perfusion Machine

Twenty-six human cadaveric kidneys have been preserved for up to 36 hours by continuous perfusion with 4.5% albumin solution on a Gambro machine. Of these, 20 kidneys were transplanted, and six were discarded owing to poor perfusion characteristics during storage. Immediate function was obtained with four kidneys, of which two had been preserved for over 30 hours.Satisfactory renal function has been obtained with 17 kidneys, and three kidneys were lost owing to rejection or technical complications. It is our experience that human kidneys can be successfully preserved for up to 36 hours by this technique.

Organ storage by hypothermia: 1. Biological aspects

Of the various organs which have been transplanted in experimental studies it is probably true to say that only the kidney has been widely accepted into surgical practice. For this reason the present discussion will be limited to the field of renal transplantation. The surgeon's requirement for preservation of human kidneys taken from cadaveric donors is a portable system which will afford immediate life sustaining function of the transplanted organ, and will allow time for tissue typing to be carried out, and for the recipient to be prepared. This requirement has not yet been met in full. The effect of deprivation of blood supply (ischaemia) on renal tissue at body temperature is relevant to renal preservation when the organ is to be removed from a recently deceased donor. Wickham 1 has shown in the rabbit that 10 minutes of ischaemia leads to a transient detectable impairment of renal function. Increasing periods of ischaemia produce more severe damage until at 1 hour only 20% of normal function remains. Recovery to normality after this degree of damage may take 10 to 14 days and is not always complete. Beyond 60 minutes of ischaemia depression of renal function is severe and recovery, if it occurs, is far from complete.