Use of UW solution in pancreas transplantation

Anti-Oxidative Therapy in Islet Cell Transplantation

Islet cell transplantation has become a favorable therapeutic approach in the treatment of Type 1 Diabetes due to the lower surgical risks and potential complications compared to conventional pancreas transplantation. Despite significant improvements in islet cell transplantation outcomes, several limitations hamper long-term graft survival due to tremendous damage and loss of islet cells during the islet cell transplantation process. Oxidative stress has been identified as an omnipresent stressor that negatively affects both the viability and function of isolated islets. Furthermore, it has been established that at baseline, pancreatic β cells exhibit reduced antioxidative capacity, rendering them even more susceptible to oxidative stress during metabolic stress. Thus, identifying antioxidants capable of conferring protection against oxidative stressors present throughout the islet transplantation process is a valuable approach to improving the overall outcomes of islet cell transplantation. In this review we discuss the potential application of antioxidative therapy during each step of islet cell transplantation.

Liver Graft Hypothermic Static and Oxygenated Perfusion (HOPE) Strategies: A Mitochondrial Crossroads

Marginal liver grafts, such as steatotic livers and those from cardiac death donors, are highly vulnerable to ischemia-reperfusion injury that occurs in the complex route of the graft from "harvest to revascularization". Recently, several preservation methods have been developed to preserve liver grafts based on hypothermic static preservation and hypothermic oxygenated perfusion (HOPE) strategies, either combined or alone. However, their effects on mitochondrial functions and their relevance have not yet been fully investigated, especially if different preservation solutions/effluents are used. Ischemic liver graft damage is caused by oxygen deprivation conditions during cold storage that provoke alterations in mitochondrial integrity and function and energy metabolism breakdown. This review deals with the relevance of mitochondrial machinery in cold static preservation and how the mitochondrial respiration function through the accumulation of succinate at the end of cold ischemia is modulated by different preservation solutions such as IGL-2, HTK, and UW (gold-standard reference). IGL-2 increases mitochondrial integrity and function (ALDH2) when compared to UW and HTK. This mitochondrial protection by IGL-2 also extends to protective HOPE strategies when used as an effluent instead of Belzer MP. The transient oxygenation in HOPE sustains the mitochondrial machinery at basal levels and prevents, in part, the accumulation of energy metabolites such as succinate in contrast to those that occur in cold static preservation conditions. Additionally, several additives for combating oxygen deprivation and graft energy metabolism breakdown during hypothermic static preservation such as oxygen carriers, ozone, AMPK inducers, and mitochondrial UCP2 inhibitors, and whether they are or not to be combined with HOPE, are presented and discussed. Finally, we affirm that IGL-2 solution is suitable for protecting graft mitochondrial machinery and simplifying the complex logistics in clinical transplantation where traditional (static preservation) and innovative (HOPE) strategies may be combined. New mitochondrial markers are presented and discussed. The final goal is to take advantage of marginal livers to increase the pool of suitable organs and thereby shorten patient waiting lists at transplantation clinics.

Clinical guideline for vascularized composite tissue cryopreservation

At the Summit on Organ Banking through Converging Technologies held recently in Boston, tissue and organ cryopreservation technology was a topic of considerable interest. Although cryopreservation has been widely used in clinical practice, it currently remains limited to bloodless tissues with simple structures and functions that are small or thin, for example, ultra-thin skin, ovarian tissue slices, and other similar tissues. For whole organs, except for successful cryopreservation of rat ovaries (2002) and hind limbs (August 2002), successful cryopreservation of vascularized animal tissues or organs and their replantation have not yet been reported. We conducted histological and electron microscopic examinations on muscle after blood supply restoration to explain this problem and describe our experience with the goal of informing our colleagues to further develop the technology. To achieve broad application of vascularized tissue and organ cryopreservation, we have summarized our experience and established a clinical application scope for vascularized composite tissue cryopreservation.

Donor risk factors in pancreas transplantation

The aim of the work was to analyze and expose the donor and recipient risk factors in pancreas transplantation. In the following paper, we exposed the 2018 Spanish Consensus Document on Donor and Recipient Selection Criteria for Pancreas Transplantation. An assessment of the previous Selection Criteria for Donors and Recipients of Pancreas Transplantation, published in 2005 by the Spanish Pancreas Transplant Group (GETP) and the National Transplant Organization (ONT) was performed. A literature review was performed using Cochrane Library, PubMed and Google Scholar databases. Some of the following terms were used for the literature search: “Diabetes Mellitus,” “Pancreas Transplantation,” “Insulin-Secreting Cells,” “Pancreas Allograft Thrombosis,” “Allograft Pancreatitis,” “Donors’ Risk Factors,” “Recipients’ Risk Factors,” “Pancreas Allograft Rejection” and “Pancreas Allograft Survival.” After an extended search, different inclusion criteria were established. Articles and documents with abstracts of full text and in English or Spanish language were selected. Subsequently, different scientific meetings took place during 2015 and 2016 by the GETP. Finally, the updated criteria were published by the GETP and ONT in 2018. Several risk factors have been described in pancreas transplantation that can be divided into donor risk factors: Advanced age (> 50 years); high body mass index (BMI) (> 30 kg/m²); cause of death (e.g., stroke); previous hyperglycemia; hyperamylasemia; cold ischemia time (greater than 8 or 12 h, depending on the type of donation); the use of vasopressors in the intensive care unit or cardiac arrest; and the macroscopic aspect of the pancreas allograft. The following are recipient risk factors: Advanced age (> 50 years); active smoking; high BMI (> 30 kg/m²); and peripheral artery disease or sensorimotor polyneuropathy. Based on the aforementioned parameters, different selection criteria have been established for the recipients depending on the type of pancreas transplantation. Knowledge of the risk factors for pancreas transplantation allows the establishment of reliable selection criteria for choosing donors and recipients.

Does pediatric heart transplant survival differ with various cardiac preservation solutions?

BACKGROUND

Few studies directly compare outcomes between the most commonly used preservation solutions in pediatric heart transplantation in a large cohort of recipients. The purpose of this study is to investigate the effect of cardiac preservation solution on survival in pediatric heart transplant recipients.

METHODS

The United Network for Organ Sharing (UNOS) database was retrospectively reviewed from 01/2004-03/2018 for pediatric donor hearts. Saline, University of Wisconsin (UW), "cardioplegia," Celsior, and Custodiol preservation solutions were evaluated. The primary endpoints were recipient survival at 30 days, 1 year, and long term.

RESULTS

After exclusion criteria, 3012 recipients had preservation solution data available. The most common preservation solution used was UW in 1203 patients (40%), followed by Celsior in 542 (18%), cardioplegia in 461 (15%), saline in 408 (14%), and Custodiol in 398 (13%). Survival of recipients whose donor hearts were procured with UW was as follows: 97%-30 day, 92%-1 year; Celsior: 97%-30 day, 92%-1 year; cardioplegia: 97%-30 day, 91%-1 year; saline: 97%-30 day, 91%-1 year; and Custodiol: 96%-30 day and 92%-1 year. Analysis of Cox models for 30-day and long-term survival revealed no statistical differences when comparing UW to Celsior (p = .333), cardioplegia (p = .914), saline (p = .980), or Custodiol (p = .642) in adjusted models.

CONCLUSIONS

There were no significant differences in 30-day or 1-year survival detected between commonly used preservation solutions in the pediatric heart transplant population.

A New Transport Solution for Parathyroid Allotransplantation: Effects on Cell Viability and Calcium-Sensing Receptors

BACKGROUND

Cold ischemia protects organs and tissues by slowing their metabolism, but it also causes ischemic injury. Minimizing cold ischemia has been an important goal in parathyroid auto- and allotransplantation, as well as the transplantation of other major organs. Parathyroid glands are responsible for calcium homeostasis by releasing parathormone (PTH) into the blood circulation. Functionality of a new parathyroid transport solution (NPTS) and effects on cell viability, PTH secretion, and calcium-sensing receptor (CaSR) levels during cold ischemia were evaluated.

MATERIALS AND METHODS

A NPTS was prepared, and the pH was adjusted to a range of 7.2-7.4 and kept at +4°C until use. Seven patients with parathyroid hyperplasia secondary to chronic renal failure who were scheduled to undergo subtotal parathyroidectomy were enrolled in the study. Glands were cold-preserved in NPTS with different time intervals (0, 6, 12, 18, and 24 hours), and then parathyroid cell viability before and after cryopreservation, PTH secretion, and CaSR levels were determined.

RESULTS

The mean cell viability before cryopreservation was 92.7% (range 89.2%-97.2%). There were no significant differences in cell viability rates before and after cryopreservation (p = 0.1168 and p = 0.4085, respectively), and CaSR levels (p = 0.5446) were not significant.

CONCLUSIONS

NPTS is a solution designed specifically for parathyroid tissue transplantation. This patent pending product can support cellular viability and PTH release, as well as protect CaSR functionality for up to 24 hours of cold ischemia.

Low temperature condition prevents hypoxia-induced islet cell damage and HMGB1 release in a mouse model

One of the major issues in clinical islet transplantation is the poor efficacy of islet isolation. During pancreas preservation and islet isolation, islets suffer from hypoxia as islets are highly sensitive to hypoxic conditions.Cold preservation has been applied to minimize hypoxia-induced cell damage during organ preservation.However, the studies related to hypoxia-induced islet cell damage during islet isolation are limited. Recently,we demonstrated that mouse islets contain high levels of high-mobility group box 1 protein (HMGB1), and during proinflammatory cytokine-induced damage, islets release HMGB1 outside the cell. The released HMGB1 is involved in the initial events of early islet loss. In the present study, we hypothesize that low temperature conditions could prevent both hypoxia induced islet cell damage and HMGB1 release from islets in a mouse model. Isolated mouse islets underwent normoxic condition (95% air and 5% CO(2)) at 37°C or hypoxic conditions (1% O(2), 5% CO(2), and 94% N(2)) at 37°C (hypoxia-37°C islets), 22°C (hypoxia-22°C islets), or 4°C (hypoxia-4°C islets) for 12 h. In vitro and in vivo viability and functionality tests were performed. HMGB1, IL-6, G-CSF, KC, RANTES, MCP-1, and MIP-1α levels in the medium were measured. Low temperature conditions substantially reduced hypoxia-induced necrosis (p < 0.05) and apoptosis (p < 0.05). In addition, low temperature islet culture significantly increased the insulin secretion from islets by high glucose stimulation (p < 0.05). All of the recipient mice reversed diabetes after receiving the hypoxia-4°C islets but not after receipt of hypoxia-37°C or 22°C islets. The amounts of released HMGB1, IL-6, G-CSF, KC, RANTES, MCP-1, and MIP-1α were significantly reduced in the hypoxia-4°C islets compared to those of the hypoxia-37°C islets (p < 0.05). In conclusion, low temperature conditions could prevent hypoxia-induced islet cell damage, inflammatory reactions in islets, and HMGB1 release and expression. Low temperature conditions should improve the efficacy of isolated islets.

Gene expression changes in rat pancreas transplant model after long-term cold storage of the graft in perfluorohexyloctane

BACKGROUND

Perfluorohexyloctane (PFH) is a promising storage solution that has been successfully used for pancreas preservation before islet isolation. This hyperoxygen carrier has been designed to prevent ischemic injury to the pancreas graft during cold storage. In our storage, we aimed to evaluate the impact of this solution on long-term cold storage in a rat whole pancreas transplantation model.

METHOD

Brown-Norway rats were used for syngeneic heterotopic pancreas transplantation. The procured organs were cold-stored for 18 hours in preoxygenated PFH (PFH group; n = 8) or in the University of Wisconsin solution (UW group; n = 8), or were transplanted immediately in the control group (n = 8). Two hours after reperfusion, we obtained blood and pancreas tissue samples for biochemistry and gene analyses (real-time polymerase chain reaction).

RESULTS

A significant difference between the UW and PFH group was observed in the tumor necrosis factor (TNF)β and endothelin 1 genes, which was overexpressed more than twofold in the UW group. In the blood samples, the UW group compared with the PFH group showed significantly higher levels of pancreatic amylase and lipase (94.2 ± 25.2 vs 67.7 ± 13.4 μkat/L and 5.5 ± 2.8 vs 3 ± 0.7 μkat/L, respectively; P < .05).

CONCLUSION

We found significantly lower expression levels of the endothelin 1 and TNFβ genes and lower concentrations of pancreatic amylase and lipase in the PFH group. All these findings suggest lower rate of ischemic reperfusion injury in the PFH group. These findings may result in better post-transplant outcomes after long-term cold storage in PFH compared with the UW solution. Further research in this area is required.

Recent progress in pancreatic islet transplantation

Diabetes mellitus remains a major burden. More than 200 million people are affected worldwide, which represents 6% of the world’s population. Type 1 diabetes mellitus is an autoimmune disease, which induces the permanent destruction of the β-cells of the pancreatic islets of Langerhans. Although intensive insulin therapy has proven effective to delay and sometimes prevent the progression of complications such as nephropathy, neuropathy or retinopathy, it is difficult to achieve and maintain long term in most subjects. The successes achieved over the last few decades by the transplantation of whole pancreas and isolated islets suggest that diabetes can be cured by the replenishment of deficient β cells. However, islet transplantation efforts have various limitations, including the limited supply of donor pancreata, the paucity of experienced islet isolation teams, side effects of immunosuppressants and poor long term results. The purpose of this article is to review the recent progress in clinical islet transplantation for the treatment of diabetes and to describe the recent progress on pancreatic stem/progenitor cell research, which has opened up several possibilities for the development of new treatments for diabetes.

Pancreas transplantation

Diabetes mellitus is generally treated with oral diabetic drugs and/or insulin. However, the morbidity and mortality associated with this condition increases over time, even in patients receiving intensive insulin treatment, and this is largely attributable to diabetic complications or the insulin therapy itself. Pancreas transplantation in humans was first conducted in 1966, since when there has been much debate regarding the legitimacy of this procedure. Technical refinements and the development of better immunosuppressants and better postoperative care have brought about marked improvements in patient and graft survival and a reduction in postoperative morbidity. Consequently, pancreas transplantation has become the curative treatment modality for diabetes, particularly for type I diabetes. An overview of pancreas transplantation is provided herein, covering the history of pancreas transplantation, indications for transplantation, cadaveric and living donors, surgical techniques, immunosuppressants, and outcome following pancreas transplantation. The impact of successful pancreas transplantation on the complications of diabetes will also be reviewed briefly.

Pancreatic islet transplantation

Type 1 diabetes mellitus is an autoimmune disease, which results in the permanent destruction of β-cells of the pancreatic islets of Langerhans. While exogenous insulin therapy has dramatically improved the quality of life, chronic diabetic complications develop in a substantial proportion of subjects and these complications generally progress and worsen over time. Although intensive insulin therapy has proven effective to delay and sometimes prevent the progression of complications such as nephropathy, neuropathy or retinopathy, it is difficult to achieve and maintain long term in most subjects. Reasons for this difficulty include compliance issues and the increased risk of severe hypoglycemic episodes, which are generally associated with intensification of exogenous insulin therapy. Clinical studies have shown that transplantation of pancreas or purified pancreatic islets can support glucose homeostasis in type 1 diabetic patients. Islet transplantation carries the special advantages of being less invasive and resulting in fewer complications compared with the traditional pancreas or pancreas-kidney transplantation. However, islet transplantation efforts have limitations including the short supply of donor pancreata, the paucity of experienced islet isolation teams, side effects of immunosuppressants and poor long-term results. The purpose of this article is to review recent progress in clinical islet transplantation for the treatment of diabetes.

Islet cell transplantation for the treatment of type 1 diabetes in the USA

Islet cell transplantation (ICTx) is one of the most effective treatments for type 1 diabetes and is less invasive compared to whole organ transplantation. The US has been the leader in the research and clinical applications of ICTx for the last 40 years. ICTx requires complex procedures, including pancreas procurement and preservation; pancreas digestion; islet purification; and transplantation. Even with the dramatic progresses in each of the procedures listed above, there are still challenges to make ICTx the standard therapy. These challenges are: (1) obtaining enough islets from a single donor and (2) preventing graft loss due to allogenic rejection and recurrence of autoimmune islet destruction. A new preservation strategy for pancreata and pancreatic ducts using ET-Kyoto solution as well as a new islet purification method using iodixanol has substantially improved islet yields. Continuous research to improve the efficacy of islet isolation will solve the issue of obtaining enough islets from a single donor. Immunological tolerance is an ideal solution for the issue of rejection and autoimmune recurrence and a regulatory T cell strategy seems promising. Moreover, the SUITO index is a simple and powerful tool to assess engrafted islet mass and is, therefore, useful for evaluating the efficacy of new immunosuppressant strategies. Once ICTx becomes a standard treatment, the donor shortage will become the next challenge. Marginal or living donor islet transplantations could help alleviate this issue; however, bio-artificial islet transplantation with animal islets could be the ultimate solution.

Current status of islet cell transplantation

Despite substantial advances in islet isolation methods and immunosuppressive protocol, pancreatic islet cell transplantation remains an experimental procedure currently limited to the most severe cases of type 1 diabetes mellitus. The objectives of this treatment are to prevent severe hypoglycemic episodes in patients with hypoglycemia unawareness and to achieve a more physiological metabolic control. Insulin independence and long term-graft function with improvement of quality of life have been obtained in several international islet transplant centers. However, experimental trials of islet transplantation clearly highlighted several obstacles that remain to be overcome before the procedure could be proposed to a much larger patient population. This review provides a brief historical perspective of islet transplantation, islet isolation techniques, the transplant procedure, immunosuppressive therapy, and outlines current challenges and future directions in clinical islet transplantation.

Preservation of pancreas tissue during cold storage assessed by X-ray microanalysis

Clinical transplantation requires cold storage of tissue for several hours. We have examined the elemental content in exocrine and endocrine cells in mouse pancreas after cold storage by X-ray microanalysis, and in parallel carried out morphological studies. Tissue was stored at 4 degrees C for 4-12 h in Normal Krebs-Ringer's (high Na+/K+ ratio), Modified Krebs-Ringer's (low Na+/K+ ratio), Euro-Collins, University of Wisconsin (UW) solution, and seven modified version of UW solution. Incubation in Normal Krebs-Ringer's solution caused significantly increased Na and decreased K concentrations in contrast to incubation in other solutions. The cellular concentration of Na and Cl followed the concentration in the storage solution. Changes in the endocrine cells were similar to, but less pronounced than those in exocrine cells. Calcium was retained best in UW and some variants of UW, and least in Euro-Collins. This may indicate differences in preservation of secretory granules. Also, morphological studies showed that endocrine cells were less affected than exocrine cells. In conclusion, the only factor determining the intracellular concentration of diffusible ions after cold tissue storage is the ionic composition of the extracellular medium. X-ray microanalysis provides an objective method to assess whether the intracellular ionic composition of tissue is maintained during storage.

Effects of University of Wisconsin and lactated Ringer's solutions to ischemia-reperfusion injury in isolated cremaster flap

Ischemia-reperfusion (I/R) injury is a topic that has been much-discussed by various researchers during the last decade in plastic surgery. Though much progress has occurred, the problem is not totally solved yet. In particular, the pathophysiology of reperfusion injury in skeletal muscle has not been clearly elucidated. The aims of this study are to assess the effects of a variety of perfusants on the microcirculation after reperfusion injury and to better understand the pathophysiology of reperfusion injury. Isolated cremaster flaps were performed in 44 rats, preserving the femoral artery and vein in order to cannulate with microtubes. There were 2 control and 2 experiment groups. In one of the control groups and in both experimental groups, 2 h of ischemia were applied by clamping the iliac vessels. Immediately after this, the muscle was locally perfused and washed with lactated Ringer's (LR) and University of Wisconsin (UW) solutions, given from the femoral artery and drained by the femoral vein in the two respective experimental groups. The effects of these solutions to I/R injury were shown at the microcirculatory level via measuring and determining preischemic and postischemic diameters of arterioles and venules, tissue perfusion, capillary density, velocity of red blood cells, and leukocyte sticking. Both tested perfusion solutions were found to be harmful in all parameters. This study demonstrates that both LR and UW solutions aggravate I/R injury.

The optimal pressure for initial flush with UW solution in heart procurement

OBJECTIVE

University of Wisconsin (UW) solution is widely used in organ preservation. Some investigators have reported that high pressure during initial flush with UW solution may induce vasoconstriction and endothelial damage, because of its high potassium content and high viscosity. However, using lower pressure during the initial flush may lead to irregular distribution of the solution and incomplete flushing of blood components from coronary vascular beds. This experimental study evaluated the effects of a range of initial flush pressures during heart procurement, followed by orthotopic transplantation of the graft after 12 hours of preservation.

MATERIALS AND METHODS

Twelve pairs of adult mongrel dogs, weighing 9 to 14 kg, formed the recipient-donor combinations. After determining hemodynamic status by measuring cardiac output, left ventricular pressure (LVP), and maximum positive and negative change in LVP (+/-LVdP/dt), donor hearts were excised. Coronary vascular beds were flushed with 4 degrees C UW solution at a pressure of 60 mm Hg in the low-pressure group (n = 6) and at 120 mm Hg in the high-pressure group (n = 6). After 12 hours of cold preservation, orthotopic transplantation was performed using cardiopulmonary bypass (CPB). The hemodynamics of the transplanted graft were assessed by comparing recovery rates (%) from donor hearts 2 hours after weaning from CPB. Endothelin-1 (ET-1) levels were measured in the blood obtained from the coronary sinus 30 minutes after reperfusion. The transplanted grafts were then harvested for histologic study and measurement of adenosine triphosphate (ATP) content.

RESULTS

Cardiac output, LVP, LVdP/dt and myocardial tissue ATP content were significantly better (p < 0.05) in the high-pressure group than in the low-pressure group. We found no significant differences in ET-1 levels between the groups. Transmission electron microscopic findings revealed that degeneration of the mitochondria was less extensive in the high-pressure group than in the low-pressure group. We observed no obvious ultrastructural damage to the endothelial cells in either group.

CONCLUSION

When using UW solution in heart procurement, high pressure is better to completely wash out the blood components and distribute the solution.

Prolonged preservation increases surgical complications after pancreas transplants

BACKGROUND

Prolonged preservation of the donor organ may result in delayed graft function or nonfunction after most organ transplants. We studied whether or not prolonged preservation increases surgical complications after pancreas transplants.

METHODS

Between January 1, 1994, and September 30, 1998, a total of 294 recipients underwent cadaver pancreas transplants at our institution. Recipients were analyzed in 2 groups: those with pancreas preservation time < or = 20 hours (n = 211) versus > 20 hours (n = 83).

RESULTS

Demographic data were similar between the 2 groups, except that mean donor age in the prolonged preservation group was significantly lower. Despite use of younger donors, prolonged preservation was associated with an increased incidence of surgical complications, most notably leaks, thrombosis, and wound infections. Grafts with prolonged preservation were more often noted by the transplant surgeon to be edematous after reperfusion, although the incidence of hyperamylasemia posttransplant did not differ between the 2 groups. Graft and patient survival rates also did not differ between the 2 groups. The incidence of early graft loss (< 3 months) was, however, higher in the prolonged preservation group (20.5% versus 9.0%, P = .04).

CONCLUSIONS

Prolonged preservation of the donor organ increases the incidence of surgical complications after pancreas transplants. All attempts should be made to minimize preservation time, keeping it below 20 hours, if possible.

Long-term outcome of simultaneous kidney-pancreas transplantation: analysis of 61 patients with more than 5 years follow-up

BACKGROUND

The long-term outcome of simultaneous kidney pancreas transplant recipients is not well established.

METHODS

We retrospectively reviewed all patients who underwent simultaneous kidney-pancreas transplantation with bladder drainage at our center between January 1989 and December 1991. A total of 57 patients (93%) were alive with functioning grafts 1 year after transplantation and were followed for a minimum of 5 years. These patients formed the study group.

RESULTS

Five-year actual patient, kidney and pancreas survival rates were 95%, 85%, and 88%, respectively. Fasting serum glucose fell from 198 mg/dL preoperatively to 94 mg/dL and remained stable thereafter. Glycohemoglobin levels decreased from 9.8% preoperatively to 4.8% 1 year after transplantation and remained normal thereafter. Kidney function remained good, with mean serum creatinine of 2.0 and creatinine clearance of 56 ml/min throughout the follow-up period. Hospital admissions decreased significantly with increasing time after transplantation from a mean of 1.2 admissions per patient in the 1st year to a mean of 0.2 admissions per patient 6 years after transplantation. Of the readmissions, 42% were for <48 hr and the most common reasons for readmission were infection, surgery, and dehydration. Mean systolic blood pressure decreased from 166 mm Hg before the transplant to 142 mm Hg 1 year after the transplant.

CONCLUSIONS

Simultaneous kidney pancreas transplantation is a safe and effective method to treat advanced diabetic nephropathy and is associated with stable metabolic function, decreased cholesterol, improved hypertension control, improved rehabilitation over time, and little morbidity or mortality after the 1st year.

A comparative study of Celsior and University of Wisconsin solutions based on 12-hr preservation followed by transplantation in canine models

BACKGROUND

Celsior is a recently developed extracellular-type preservation solution that is effective in organ preservation. This experimental study was designed to compare the effects of Celsior and University of Wisconsin (UW) solutions in myocardial protection, using 12-hour preservation followed by orthotopic transplantation.

METHODS

Fourteen pairs of adult mongrel dogs were divided into 2 groups. In the UW group (n = 7), UW solution at 4 degrees C was used for coronary vascular washout and storage following cardiac arrest with glucose-insulin-potassium (GIK) solution. In the Celsior group (n = 7), Celsior solution was used to produce cardiac arrest, for coronary vascular washout, and for storage. After 12-hour cold preservation, orthotopic transplantation was performed under cardiopulmonary bypass (CPB). The rate of recovery (%) of cardiac function of donor hearts was compared 1 and 2 hours after weaning from CPB, and then the transplanted hearts were harvested for histological study.

RESULTS

Hemodynamic parameters including cardiac output, left ventricular pressure (LVP), and the maximum rates of positive and negative increase of LVP after transplantation were significantly (p < 0.05) higher in the Celsior group than in the UW group 2 hours after weaning from CPB. The transmission electron microscopic study found that degeneration of the mitochondria in the Celsior group was less extensive than in the UW group.

CONCLUSION

Celsior solution enhanced the cardiac function of hearts preserved for 12 hours prior to transplantation compared to UW solution. Our results indicate that Celsior solution is equivalent or superior to UW solution for cardiac preservation.

Experience with 500 simultaneous pancreas-kidney transplants

METHODS

From December 1985 to October 1997, 500 simultaneous pancreas-kidney transplants (SPKs) were performed at the University of Wisconsin. Bladder drainage (BD) was used in 388 and enteric drainage (ED) in 112. All pancreas transplants were preserved in UW solution.

RESULTS

Patient survival at 1, 5, and 10 years was 96.4%, 88.6%, and 76.3%; kidney function, 88.6%, 80.3%, and 66.6%; and pancreas function, 87.5%, 78.1%, and 67.2%. Thrombosis of the pancreas occurred in three to four (0.6% to 0.8%) and primary nonfunction in one (0.2%). There was a 4.2% acute tubular necrosis rate for the kidney. Conversion from BD to ED was required in 24% of cases. Primary indications for enteric conversion (EC) were leak (14%), urethritis and extravasation (7%), and chronic hematuria (3%). No graft was lost as a result of EC. There was no difference in 1-year graft survival between ED and BD. Leading causes of pancreas loss were rejection in 45 patients and death with a functioning graft in 27 patients. Since June 1995, mycophenolate mofetil was used for immunosuppression (n = 109). One-year survival rates with mycophenolate mofetil are patient, 98.1 %; kidney, 94.2%; and pancreas, 93.1%. Steroid-resistant rejections decreased from 48% to 15%.

CONCLUSIONS

This series represents the world's largest experience with SPK, including the longest follow-up for BD pancreatic transplants. Ten-year graft survival rates exceed those of all other transplants, with the exception of HLA-identical living-related grafts. This series confirms that SPK is a highly successful procedure for selected diabetic patients with renal failure.

Preservation of endothelium-dependent vasodilation with low-potassium University of Wisconsin solution

University of Wisconsin solution has provided excellent myocardial preservation. However, the high potassium content of the currently available University of Wisconsin solution has been implicated in coronary artery endothelial damage. We placed 16 neonatal (age 1 to 3 days) Duroc piglet hearts on an isolated nonworking perfusion circuit. Endothelium-dependent and endothelium-independent vasodilation were tested by measuring coronary blood flow after intracoronary infusion of bradykinin (10(-6) mol/L) and nitroprusside (10(-6) mol/L), respectively. In addition, nitric oxide levels were measured after bradykinin infusion. The hearts were then arrested blindly with either a modified University of Wisconsin solution (group 1; n = 8, K+ = 25 mEq/L) or standard University of Wisconsin solution (group 2; n = 8, K+ = 129 mEq/L) by infusion of cardioplegic solution every 20 minutes for a total of 2 hours. After bradykinin infusion, the mean coronary blood flow increased by 237.1% +/- 14.0% of baseline valves before arrest and by 232.8% +/- 16.0% after arrest in group 1 (p = not significant). As in the first group, the mean coronary blood flow in group 2 increased by 231.1% +/- 13.7% before arrest; however, the increase in mean coronary blood flow after arrest was significantly attenuated (163.3% +/- 12.8%, p < 0.01). The loss of endothelium-dependent coronary blood flow response in group 2 correlated with a decreased capacity to release nitric oxide after arrest (prearrest 8.25 +/- 2.30 nmol/min per gram versus postarrest -2.46 +/- 2.29 nmol/min per gram, p < 0.01). Endothelium-independent vasodilatory response revealed no significant difference between groups before and after arrest. These results suggest that the low-potassium University of Wisconsin solution provides superior protection of the endothelium by preserving the endothelium-dependent vasodilatory response to nitric oxide release.

Rescue therapy with tacrolimus after combined kidney/pancreas and isolated pancreas transplantation in patients with severe cyclosporine nephrotoxicity

This study details 11 pancreas transplant recipients (10 combined kidney and pancreas and 1 pancreas after kidney) who were converted to tacrolimus (FK506) due to acute severe cyclosporine nephrotoxicity in 8 cases and persistent rejection with cyclosporine toxicity in three cases. Arteriolopathy was documented by renal histology in all cases. Cyclosporine was discontinued for 24 hr immediately prior to initiation of tacrolimus. Tacrolimus was started orally at 0.1 mg/kg twice daily with dose adjustments to maintain whole blood trough levels of 8-15 ng/mL by IMx. Tacrolimus was initiated a mean of 14.5 months (range 1-81) after pancreas transplantation. The mean serum creatinine level had increased to 2.9 mg/dl from 1.0 mg/dl at the diagnosis of cyclosporine arteriolopathy (P=0.003). The mean serum creatinine and blood glucose levels at the time of initiation of tacrolimus were 2.1 mg/dl and 104 mg/dl, respectively. Serum creatinine was 1.7 mg/dl, 1.9 mg/dl, 1.8 mg/dl, and 1.7 mg/dl after 1, 2, 3, and 6 months of tacrolimus therapy, respectively; ANOVA (P = 0.02). The corresponding blood glucose levels were 117 mg/dl, 112 mg/dl, 109 mg/dl, and 116 mg/dl, respectively (P=NS). Normal C-peptide levels were present before (5.9 ng/ml) and after (6.2 ng/ml), the initiation of tacrolimus therapy (P=NS), and mean HbA1C was 6.1% before and 6.3% after tacrolimus therapy, (P=NS). There were 4 episodes of acute rejection, 3 responded to intravenous methylprednisolone, and 1 required OKT3 during tacrolimus therapy. Reversible tacrolimus nephrotoxicity was noted in three patients without any evidence of progressive vasculopathy. All 11 patients are alive, and 10/11 kidney and pancreas grafts are functioning with a mean follow-up of 7.7 months (range 5-10). In this study, conversion from cyclosporine to tacrolimus in kidney and pancreas recipients resulted in improvement and stabilization of renal function while maintaining stable blood glucose, C peptide, and HbA1C levels.

Pancreas transplantation for diabetes mellitus

Pancreas transplantation has become a viable option for the patient wi th insulin-dependent diabetes mellitus with progressive renal failure. The most common type of pancreas transplantation is a simultaneous pancreas and kidney transplantation performed from a single cadaver donor (SPK). The next most common is pancreas transplantation after successful kidney transplantation (PAK). A few centers are performing pancreas transplantation alone (PTA) in diabetic recipients without renal disease but who have significant complications from their diabetes. Pancreas transplantation is associated with a higher morbidity than kidney transplantation alone. Most pancreas transplantation centers report a significant increase in acute rejection, which can lead to increased hospitalization and risk of opportunistic infection. In addition, the early era of pancreas transplantation was associated with significant surgical complications. However, with bladder drainage of the pancreas exocrine secretions, the surgical complication rate has decreased significantly. Despite medical and surgical complications, the overall results for pancreas transplantation are excellent, with 1 -year graft survival of 75% for SPK transplantations and 48% for PAK and PTA transplant recipients. The effects of a pancreas transplantation on the secondary complications of diabetes have been studied extensively. Most studies have shown a modest improvement in secondary complications with the exception of diabetic retinopathy. The major benefit of pancreas transplantation appears to be enhanced quality of life for patients successfully transplanted. For these reasons, the Kidney-Pancreas Committee of the American Society of Transplant Physicians believes the current results of pancreas-kidney transplantation justify its use as a valid option for insulin-dependent diabetic transplant recipients.

Improved long-term preservation of the coronary vasculature with University of Wisconsin solution

Experiments were designed to investigate coronary vascular function after prolonged cold storage of isolated rat hearts, using University of Wisconsin (UW) solution. Hearts perfused with crystalloid cardioplegic solution (Plegisol) were used as controls. After perfusion with 10 ml at 4 degrees C, hearts were stored for 1 or 10 hours in the respective solutions at 4 degrees C. To evaluate coronary vascular function after perfusion and storage, endothelium-dependent vasodilation was induced with 5-hydroxytryptamine (5-HT) and smooth muscle-dependent dilation with nitroglycerin (GTN). After perfusion only, or perfusion plus 1-hour storage, there was no intergroup difference in response to 5-HT and GTN. After 10-hour storage the vasodilatory response to 5-HT was abolished in the Plegisol group and slight vaso-constriction was observed, whereas in the UW group the vasodilatory effect of 5-HT persisted. The findings suggest that UW solution may be more favorable for prolonged cardiac preservation, as the coronary vascular reactivity was less affected.

Preserved incretin effect in type 1 diabetic patients with end-stage nephropathy treated by combined heterotopic pancreas and kidney transplantation

Insulin secretion is stimulated better by oral than by intravenous glucose (incretin effect). The contribution of the autonomic nervous system to the incretin effect after oral glucose in humans is unclear. We therefore examined nine type 1 diabetic (insulin-dependent) patients with end-stage nephropathy, studied after combined heterotopic pancreas and kidney transplantation, and 7 non-diabetic kidney recipients (matched for creatinine clearance and immunosuppressive medication). The release of gastric inhibitory polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) immunoreactivity and B cell secretory responses (IR insulin and C-peptide) to oral (50 g) and "isoglycaemic" intravenous glucose (identical glycaemic profile) were measured by radioimmunoassay. The difference in B cell responses between the two tests represents the contribution of the enteroinsular axis to the response after oral glucose (incretin effect). Insulin responses after the oral glucose challenge were similar in the two patient groups despite systemic venous drainage of the pancreas graft in the pancreas-kidney-transplanted group. In both groups GIP and GLP-1 increased after oral but not after intravenous glucose, and B cell secretory responses were significantly smaller (by 55.2 +/- 7.7% and 46.5 +/- 12.5%, respectively) with "isoglycaemic" intravenous glucose infusions. The lack of reduction in the incretin effect in pancreas-kidney-transplanted patients, whose functioning pancreas is denervated, indicates a lesser role for the nervous system and a more important contribution of circulating incretin hormones in mediating the enteroinsular axis in man.

Six-hour preservation of the isolated working rat heart improved with University of Wisconsin solution

University of Wisconsin (UW) solution was compared with modified St. Thomas cardioplegic solution for 6-hour preservation of isolated working rat hearts. The hearts (9 in each group) were arrested with the respective solution and stored, still cannulated, for 6 hours at 4 degrees C. After retrograde reperfusion for 30 minutes, antegrade perfusion was begun at constant left atrial and aortic pressures. Following 25 minutes of antegrade perfusion the hemodynamic recovery of the UW-preserved hearts was superior to that of the other hearts (cardiac output 46.0 +/- 4.8% of the preischemic control values in the UW group and 10.0 +/- 6.0% in the St. Thomas group, p < 0.01). The adenosine triphosphate content was significantly higher in the UW-preserved hearts (18.8 +/- 0.9 vs. 14.7 +/- 1.6 mumol/g dry weight, p < 0.05). No significant intergroup difference was found in aspartate aminotransferase leak or tissue glycogen. The study demonstrated both better function and enhancement of high-energy phosphates with UW solution vs. modified St. Thomas solution in isolated rat hearts, although without difference in enzyme leakage or tissue glycogen, after 6-hour preservation.

Surgical complications in solitary pancreas and combined pancreas-kidney transplantations

The benefits of pancreas transplantation (PT) must be weighed against the morbidity associated with the operative procedure and long-term immunosuppression. Over a 32-month period, we performed 73 PTs including 61 combined pancreas-kidney transplants (PKT) and 12 solitary PTs. In the PKT group, 25 reoperations were performed in 18 patients (29.5%) at a mean of 39 +/- 12 days after transplant. In the solitary PT group, 16 reoperations were performed in 8 recipients (66.7%, p = 0.03) at a mean of 87 +/- 12 days after PT (p < 0.01). In the PKT group, pancreas allograft survival was 93.4%. Vascular thrombosis resulted in the loss of two pancreas allografts. In the solitary PT group, pancreas allograft survival was 50% (p < 0.001), with 6 transplant pancreatectomies performed for either infectious (5) or vascular (1) complications. Surgical complications after PT are common (35.6% in this series), occur earlier in patients who undergo PKT, and are more frequent and morbid in patients undergoing solitary PT, especially after a previous kidney transplant. An aggressive surgical approach can lead to a high rate of pancreas allograft salvage without jeopardizing either the patient or the renal allograft.

Storage of human pancreatic digest in University of Wisconsin solution significantly improves subsequent islet purification

Density-gradient purification of human pancreatic islets from the collagenase-digested pancreas relies on the exocrine tissue being denser than the islets. Cold storage of the pancreas before and after digestion causes cell swelling, which can decrease the density of pancreatic exocrine tissue and adversely affect subsequent purification. Using 14 human pancreata (seven perfused in situ with hyperosmolar citrate (HOC) and seven with University of Wisconsin solution (UW)), it is shown that storage of the pancreatic digest in UW significantly increases the density of pancreatic exocrine tissue compared with storage in minimal essential medium (MEM) (P = 0.009). This results in an improvement in islet purity (P = 0.036) for HOC- but not UW-perfused pancreata. Storage in UW for 1 h not only prevented the deterioration that occurred in MEM, but resulted in an improvement in islet purity for five of the seven HOC-perfused pancreata. Most pancreata in the UK are perfused with HOC, but storage of the digest in UW results in significantly better islet purity and, when islets cannot be purified immediately, a period of storage will often improve separation and allow islets to be purified.

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.

Basal and nutrient-stimulated pancreatic and gastrointestinal hormone concentrations in type-1-diabetic patients after successful combined pancreas and kidney transplantation

The secretion of pancreatic and gastrointestinal hormones in the basal state and after nutrient stimuli (50 g glucose, 50 g protein, or 30 g triglyceride administered on separate occasions) was assessed in ten previously type-1-diabetic patients after successful combined kidney and pancreas transplantation (systemic venous drainage). Fasting values were compared to matched non-diabetic kidney-transplanted patients and related to kidney function (endogenous creatinine clearance) and to the type and dosage of immunosuppressive medication. In the fasting state, only IR insulin concentrations were higher in pancreas-kidney-transplanted patients (by 88%; P = 0.001) than in the kidney graft recipients. There were significant inverse correlations of plasma C-peptide, GIP, and gastrin immunoreactivity to endogenous creatinine clearance (kidney function). In response to nutrients, insulin secretion (IR insulin, C-peptide) was significantly stimulated by glucose, and - to a lesser degree - also by protein. Pancreatic glucagon was suppressed by glucose and stimulated by protein ingestion. GIP was raised after glucose and triglyceride more than after protein (P = 0.0003). GLP-1 immunoreactivity was stimulated by all nutrients, with a tendency towards higher responses to protein and fat (P = 0.06). Gastrin was mainly raised by protein. In conclusion, the overall pattern of pancreatic and gastrointestinal hormone release is normal in patients after combined pancreas-kidney-transplantation, but there are some peculiarities due to (a) systemic venous drainage of the pancreas graft (elevated fasting IR insulin) and (b) impaired kidney function (negative correlation of fasting plasma values to endogenous creatinine clearance for C-peptide, GIP, and gastrin).(ABSTRACT TRUNCATED AT 250 WORDS)

University of Wisconsin solution for human donor heart preservation: initial clinical experience

Although in vitro and primate orthotopic transplant experiments have suggested the superiority of University of Wisconsin solution (UWS) compared with crystalloid cardioplegia and saline solution storage for hypothermic heart preservation, concerns about the viscosity and the high potassium concentration of UWS have precluded its use in human cardiac transplantation. To test the safety and efficacy of UWS, 16 patients received hearts arrested with, flushed with, and stored in UWS at 4 degrees C for a mean ischemic time of 153.3 +/- 30.7 minutes. After reperfusion, the hearts contracted vigorously and attained a stable sinus rhythm within 4.0 +/- 2.4 minutes, and the patients were weaned from bypass in 24.5 +/- 8.0 minutes. There was no evidence of acute or chronic ischemic myocardial injury by enzymatic analysis, electrocardiography, or biopsy specimen histology. The results suggest UWS can be safely used, within currently accepted limits of donor ischemic time, to arrest and preserve human hearts for transplantation. Further studies of preservation are required to compare UWS with crystalloid cardioplegia and saline solution storage and to test the ability of UWS to prolong the period of safe donor hypothermic ischemia in clinical heart transplantation.

Superior myocardial preservation with modified UW solution after prolonged ischemia in the rat heart

Cardiac transplantation remains constrained by poor graft tolerance of prolonged cold ischemia. University of Wisconsin solution has remarkably extended ischemic preservation in pancreas, kidney, and liver transplantation. To assess its efficacy in cardiac preservation, modified University of Wisconsin solution flush and storage were tested against St. Thomas' cardioplegia flush and normal saline solution storage after six hours of ischemia at 0 degrees C in 46 isolated rat hearts. After ischemia, groups were compared before and after reperfusion. After ischemia but before reperfusion, University of Wisconsin solution hearts had significantly less tissue water (3.8%), superior tissue sodium, potassium, calcium, and magnesium profiles, and elevated adenosine and inosine levels, and tended toward better histological preservation. After reperfusion, University of Wisconsin solution more effectively preserved left ventricular compliance (75% versus 35% of baseline), developed pressure (71% versus 45% of baseline), histological integrity, and tissue potassium and calcium profiles than St. Thomas' solution. The University of Wisconsin solution provided superior preservation of systolic and diastolic ventricular function, tissue histology, tissue water, and tissue electrolytes than did St. Thomas' cardioplegia and normal saline solution storage in this experimental model, and might result in improved graft tolerance of ischemia in clinical cardiac transplantation.

Pancreas transplantation at Mayo: II. Operative and perioperative management

Better perioperative and operative management techniques have contributed to an improvement in the success rate of pancreas transplantation. Because of a shortage of donor organs, the criteria for acceptability of the allograft have been liberalized, and the development of techniques such as combined liver and pancreas procurement has increased allograft availability. Major advances have been made in organ preservation. Currently, pancreas allografts can routinely be stored for 18 to 24 hours. The technique of pancreaticoduodenal transplantation with a duodenocystostomy for the exocrine drainage is widely used. Experience with anesthetic and intensive-care unit management of these patients is accumulating. With the evolution of pancreas transplantation and with the help of the excellent transplant centers in our area, we developed a pancreas transplantation protocol and performed transplantation based on this protocol in 16 recipients at the Mayo Clinic from October 1987 through December 1988.