Pancreatico-duodenal allotransplantation: experimental and clinical experience

CT fluoroscopy-guided pancreas transplant biopsies: a retrospective evaluation of predictors of complications and success rates

To identify predictors of biopsy success and complications in CT-guided pancreas transplant (PTX) core biopsy. We retrospectively identified all CT fluoroscopy-guided PTX biopsies performed at our institution (2000-2017) and included 187 biopsies in 99 patients. Potential predictors related to patient characteristics (age, gender, body mass index (BMI), PTX age, PTX volume) and procedure characteristics (biopsy depth, needle size, access path, number of samples, interventionalist's experience) were correlated with biopsy success (sufficient tissue for histologic diagnosis) and the occurrence of complications. Biopsy success (72.2%) was more likely to be obtained in men [+25.3% (10.9, 39.7)] and when the intervention was performed by an experienced interventionalist [+27.2% (8.1, 46.2)]. Complications (5.9%) occurred more frequently in patients with higher PTX age [OR: 1.014 (1.002, 1.026)] and when many (3-4) tissue samples were obtained [+8.7% (-2.3, 19.7)]. Multivariable regression analysis confirmed male gender [OR: 3.741 (1.736, 8.059)] and high experience [OR: 2.923 (1.255, 6.808)] (biopsy success) as well as older PTX age [OR: 1.019 (1.002, 1.035)] and obtaining many samples [OR: 4.880 (1.240, 19.203)] (complications) as independent predictors. Our results suggest that CT-guided PTX biopsy should be performed by an experienced interventionalist to achieve higher success rates, and not more than two tissue samples should be obtained to reduce complications. Caution is in order in patients with older transplants because of higher complication rates.

Defining the Burden of Emergency General Surgery in Transplant Patients: A Nationwide Examination

BACKGROUND

Transplant patients are at the risk of serious sequelae from medical and surgical intervention. The incidence and burden of emergency general surgery (EGS) in transplant patients are scarcely known. This study aims to identify predictors of outcomes in transplant patients with EGS needs.

METHODS

The Nationwide Inpatient Sample (2007-2011) was queried for adult patients (aged ≥16 y) who underwent abdominal visceral transplantation. These were further queried for a secondary diagnosis of an American Association for the Surgery of Trauma-defined EGS condition. Outcome measures included mortality, complications, length of stay, and cost of care. Propensity scores were used to match patients across baseline characteristics. Multivariate analysis was used to further adjust propensity score quintiles and hospital-level characteristics.

RESULTS

A total of 35,573 transplant patients were identified. Of these, 30% (n = 10,676) developed an EGS condition. Most common EGS conditions were resuscitation (7.7%), intestinal obstruction (7.3%), biliary conditions (3.9%), and hernias (3.2%). Patients with public insurance, those in the highest income quartile, and those treated at larger hospitals had a lower likelihood of developing an EGS condition (P < 0.05). Patients with an EGS condition had a ninefold higher likelihood of mortality and a threefold higher likelihood of developing complications (odds ratio [95% confidence interval (CI)]: 9.21 [1.80-10.89] and 3.17 [3.02-3.34], respectively). Transplant patients after EGS had a longer risk-adjusted length of stay and cost of index hospitalization (Absolute difference [95% CI]: 12.70 [12.14-13.26] and $57,797 [55,415-60,179], respectively]).

CONCLUSIONS

Transplant patients fare poorly after developing an EGS condition. The results of this study will help in identifying at-risk patients and determining outcomes.

Surgery of pancreas transplantation

PURPOSE OF REVIEW

The surgical techniques of pancreas transplantation have been evolving and significantly improved over time. This article discusses different current techniques and their modifications.

RECENT FINDING

At this time, the most commonly used technique is systemic venous drainage (for venous outflow) and enteric drainage (for management of exocrine pancreatic secretions). However, new modifications of established techniques such as gastric or duodenal exocrine drainage and venous drainage to the inferior vena cava continue to be introduced.

SUMMARY

This article provides a state-of the-art review of the most prevalent up-to-date surgical techniques as well as a synopsis of their specific risks and benefits. The article also provides the most current registry data regarding utilization of different surgical techniques in the United State and worldwide.

Outcomes in Pancreas Transplantation With Exocrine Drainage Through a Duodenoduodenostomy Versus Duodenojejunostomy

Until recently, pancreas transplantation has mostly been performed with exocrine drainage via duodenojejunostomy (DJ). Since 2012, DJ was substituted with duodenoduodenostomy (DD) in our hospital, allowing endoscopic access for biopsies. This study assessed safety profiles with DD versus DJ procedures and clinical outcomes with the DD technique in pancreas transplantation. DD patients (n = 117; 62 simultaneous pancreas-kidney [SPK_DD ] and 55 pancreas transplantation alone [PTA_DD ] with median follow-up 2.2 years) were compared with DJ patients (n = 179; 167 SPK_DJ and 12 PTA_DJ ) transplanted in the period 1998-2012 (pre-DD era). Postoperative bleeding and pancreas graft vein thrombosis requiring relaparotomy occurred in 17% and 9% of DD patients versus 10% (p = 0.077) and 6% (p = 0.21) in DJ patients, respectively. Pancreas graft rejection rates were still higher in PTA_DD patients versus SPK_DD patients (p = 0.003). Hazard ratio (HR) for graft loss was 2.25 (95% CI 1.00, 5.05; p = 0.049) in PTA_DD versus SPK_DD recipients. In conclusion, compared with the DJ procedure, the DD procedure did not reduce postoperative surgical complications requiring relaparatomy or improve clinical outcomes after pancreas transplantation despite serial pancreatic biopsies for rejection surveillance. It remains to be seen whether better rejection monitoring in DD patients translates into improved long-term pancreas graft survival.

Pancreas transplantation: Advantages of a retroperitoneal graft position

INTRODUCTION

In the 50 years since the first pancreas transplant performed at the University of Minnesota, the surgical techniques employed have undergone many modifications. Techniques such as retroperitoneal graft placement have further improved the ability to reproduce the physiology of the «native» pancreas. We herein present our experience of a modified technique for pancreatic transplant, with the organ placed into a fully retroperitoneal position with systemic venous and enteric drainage of the graft by duodeno-duodenostomy.

METHODS

All pancreas transplantations performed between May 2016 and January 2017 were prospectively entered into our transplant database and retrospectively analyzed.

RESULTS

A total of 10 transplants were performed using the retroperitoneal technique (6 men: median age of 41 years [IQR 36-54]). Median cold ischemia times was 10,30h [IQR 5,30-12,10]. The preservation solution used was Celsior (n=7), IGL-1 (n=2), and UW (n=1). No complications related to the new surgical technique were identified. In one patient, transplantectomy at 12h was performed due to graft thrombosis, probably related to ischemic conditions from a donor with prolonged cardio-respiratory arrest. Another procedure was aborted without completing the graft implant due to an intraoperative immediate arterial thrombosis in a patient with severe iliac atheromatosis. No primary pancreas non-function occurred in the remaining 8patients. The median hospital stay was 13,50 days [IQR 10-27].

CONCLUSIONS

Retroperitoneal graft placement appears feasible with easy access for dissection the vascular site; comfortable technical vascular reconstruction; and a decreased risk of intestinal obstruction by separation of the small bowel from the pancreas graft.

Pancreas transplantation: 50 years of experience

In December 1966, the first pancreas transplant ever was performed at the University of Minnesota. R. Lillehei and W. Kelly, transplanted a kidney and a pancreas in a diabetic patient on dialysis, getting function of both organs. Since then, the technical and immunological advances in this transplant have resulted in graft and patient survival results as the rest of the abdominal solid organ transplants. The balance of these 50 years is that more than 50,000 diabetic patients have been transplanted in more than 200 centers around the world. In our country the first transplant was performed 34 years ago in Barcelona and now 12 centers perform about 100 transplants per year. Although advances in diabetes control have been very important, pancreas transplantation continues to be the only method that allows normalization of the carbohydrates metabolism to improve the quality of life and, above all, to increase the survival of these patients.

Pancreas Transplantation: Past, Present, Future

Diabetes is the pandemic disease of the modern era, with 10% of these patients having type 1 diabetes mellitus. Despite the prevalence, morbidities, and associated financial burden, treatment options have not changed since the introduction of injectable insulin. To date, over 40,000 pancreas transplants have been performed globally. It remains the only known method for restoring glycemic control and thus curing type 1 diabetes mellitus. The aim of this review is to bring pancreatic transplantation out of the specialist realm, informing practitioners about this important procedure, so that they feel better equipped to refer suitable patients for transplantation and manage, counsel, and support when encountering them within their own specialty. This study was a narrative review conducted in October 2015, with OVID interface searching EMBASE and MEDLINE databases, using Timeframe: Inception to October 2015. Articles were assessed for clinical relevance and most up-to-date content, with articles written in English as the only inclusion criterion. Other sources used included conference proceedings/presentations and unpublished data from our institution (Oxford Transplant Centre). Pancreatic transplantation is growing and has quickly become the gold standard of care for patients with type 1 diabetes mellitus and renal failure. Significant improvements in quality of life and life expectancy make pancreatic transplant a viable and economically feasible intervention. It remains the most effective method of establishing and maintaining euglycemia, halting and potentially reversing complications associated with diabetes.

Characterization of Insulin-Secreting Porcine Bone Marrow Stromal Cells Ex Vivo and Autologous Cell Therapy in Vivo

Cell therapy could potentially meet the need for pancreas and islet transplantations in diabetes mellitus that far exceeds the number of available donors. Bone marrow stromal cells are widely used in clinical trials mainly for their immunomodulatory effects with a record of safety. However, less focus has been paid to developing these cells for insulin secretion by transfection. Although murine models of diabetes have been extensively used in gene and cell therapy research, few studies have shown efficacy in large preclinical animal models. Here we report optimized conditions for ex vivo expansion and characterization of porcine bone marrow stromal cells and their permissive expression of a transfected insulin gene. Our data show that these cells resemble human bone marrow stromal cells in surface antigen expression, are homogeneous, and can be reproducibly isolated from outbred Yorkshire–Landrace pigs. Porcine bone marrow stromal cells were efficiently expanded in vitro to >1010 cells from 20 ml of bone marrow and remained karyotypically normal during expansion. These cells were electroporated with an insulin expression plasmid vector with high efficiency and viability, and secreted human insulin and C-peptide indicating appropriate processing of proinsulin. We showed that autologous insulin-secreting bone marrow stromal cells implanted and engrafted in the liver of a streptozotocin-diabetic pig that modeled type 1 diabetes resulted in partial, but significant, improvement in hyperglycemia that could not be ascribed to regeneration of endogenous β-cells. Glucose-stimulated insulin secretion in vivo from implanted cells in the treated pig was documented by a rise in serum human C-peptide levels during intravenous glucose tolerance tests. Compared to a sham-treated control pig, this resulted in significantly reduced fasting hyperglycemia, a slower rise in serum fructosamine, and prevented weight loss. Taken together, this study suggests that bone marrow stromal cells merit further development as autologous cell therapy for diabetes.

Role of Special Coagulation Studies for Preoperative Screening of Thrombotic Complications in Simultaneous Pancreas-Kidney Transplantation

BACKGROUND

Vascular thrombosis is a well-known complication after simultaneous pancreas-kidney (SPK) transplantation procedures. The role of preoperative special coagulation studies to screen patients at high risk for vascular thrombosis is unclear and not well studied.

METHODS

This study reports a retrospective medical record review of 83 SPK procedures performed between April 2007 and June 2013 in a single institution. All SPK transplantation recipients underwent preoperative screening for hypercoagulable state.

RESULTS

Eighteen of 83 patients (21.69%) were diagnosed with vascular thrombosis of the pancreas. Of the 23 patients with at least 1 positive screening test, only 4 had a thrombotic event (17.39%). On the other hand, 14 of 60 patients with negative screening tests developed vascular thrombosis (23.33%). The hypercoagulable screening workup had a positive predictive value of 17.39% and a negative predictive value of 76.67%. The workup also demonstrated low sensitivity (22.22%) and specificity (70.77%).

CONCLUSION

No differences were seen in patient or graft survival between groups at 12 months. This retrospective study did not show any benefit of using special coagulation studies to rule out patients at risk for vascular thrombosis after SPK transplantation.

Pancreas graft thrombosis: causes, prevention, diagnosis, and intervention

PURPOSE OF REVIEW

Pancreas graft thrombosis remains one of the most common reasons for pancreas transplant loss. Patients with a history of thrombotic events should be identified and evaluated for thrombophilia to identify transplant candidates at highest risk.

RECENT FINDINGS

Early after transplant, vascular thrombosis is multifactorial, but beyond 2 weeks, inflammation or acute rejection predominate as the cause of thrombosis. Most pancreas transplant centers utilize some form of anticoagulation following transplantation. Aspirin is highly recommended. Unfractionated or low-molecular-weight heparin is often administered, but some centers use heparin selectively and typically at low dose to avoid postoperative bleeding. Warfarin is less frequently given and its use should probably be limited to patients with thrombophilia.

SUMMARY

Thrombectomy, either surgical or percutaneous, may salvage the pancreas graft if performed early after the occurrence of thrombosis.

Evolution of pancreas transplantation: long-term results and perspectives from a high-volume center

OBJECTIVE

To describe the evolution of pancreas transplantation from 1979 to 2011. The aim was to examine factors influencing long-term patient and graft survival, surgical methods, and risk factors influencing organ performance after transplantation.

BACKGROUND

Pancreas transplantation has become the therapy of choice for patients suffering insulin-dependent diabetes and end stage renal failure.

METHODS

Retrospective analysis of 509 consecutive pancreas transplants (442 simultaneous pancreas and kidney [SPK], 20 pancreas transplanted alone [PTA], and 47 pancreas transplanted after kidney [PAK]), performed at the University Hospital Innsbruck. The data were statistically analyzed using the Kaplan-Meier method and log-rank test.

RESULTS

After overcoming initial immunological and technical problems between 1979 and 1988 (5-year pancreas graft survival rate, 29.7%), pancreas transplantation evolved during the second decade (1989-1996; 5-year pancreas graft survival rate, 42.2%). Technical changes, optimized immunosuppression, careful pretransplant evaluation, and improved graft monitoring have become standard in the last decade and result in excellent 5-year patient (94.3%), kidney (89.4%), and pancreas (81.5%) graft survival. Five-year graft survival was superior in SPK (68.8%) compared with PAK (62.5%) and PTA (16.4%). SPK retransplantation can be carried out safely with 5-year patient (87.5%) and pancreas graft (75.0%) survival. Overall 5-year patient survival after loss of the first pancreas graft is significantly better in patients who underwent retransplantation (89.4% vs. 67.9%, P = 0.001). Long-term pancreas graft survival is independent of donor body mass index, sex, and cause of death, anastomosis time and the number of human leukocyte antigen (HLA) mismatches, recipient age, body mass index, sex, current panel reactive antibodies, and waiting time. Significant risk factors for reduced graft survival are cold ischemia time and donor age.

CONCLUSIONS

During the last 32 years, many problems in pancreas transplantation have been overcome and it may currently represent the therapeutic gold standard for some patients with diabetes and end stage renal failure.

Transplantation of the pancreas

Pancreas transplantation consistently induces insulin-independence in beta-cell-penic diabetic patients, but at the cost of major surgery and life-long immunosuppression. One year after grafting, patient survival rate now exceeds 95 % across recipient categories, while insulin independence is maintained in some 85 % of simultaneous pancreas and kidney recipients and in nearly 80 % of solitary pancreas transplant recipients. The half-life of the pancreas graft currently averages 16.7 years, being the longest among extrarenal grafts, and substantially matching the one of renal grafts from deceased donors. The difference between expected (100 %) and actual insulin-independence rate is mostly explained by technical failure in the postoperative phase, and rejection in the long-term period. Death with a functioning graft remains a further major issue, especially in uremic patients who have undergone prolonged periods of dialysis. Refinements in graft preservation, surgical techniques, immunosuppression, and prophylactic treatments are expected to further improve the results of pancreas transplantation.

Richard Carlton Lillehei: transplant and shock surgical pioneer

Richard Carlton Lillehei (1927-1981) was a trainee of the Minnesota School of Surgery under Owen H. Wangensteen in the early 1950s, when great advances were being accomplished in cardiac surgery. His mentors besides Wangensteen included his brother C. Walton Lillehei, Richard L. Varco, and several others in the Department of Surgery. His interest in surgical research was evident since the early part of his training. The understanding of the nature and management of shock occupied his attention and persisted all his life. Equally, his studies on organ preservation and intestinal and pancreatic transplantation were classic in the evolution of surgery. In fact, Rich Lillehei, together with William Kelly, performed the world's first clinical pancreas transplant in 1966 and with his own team, the world's first clinical small bowel transplantation in 1967. Following that, these two areas of transplantation progressively advanced to be applied to thousands of patients worldwide. Lillehei was also a committed teacher and many of his students are disseminated throughout the globe. Unfortunately, his enormous contributions were cut short with his premature death at age 53. However, his surgical legacy remains alive!

One thousand simultaneous pancreas-kidney transplants at a single center with 22-year follow-up

OBJECTIVE

Simultaneous pancreas-kidney transplantation (SPK) is a procedure which frees the diabetic patient with end-stage nephropathy from dialysis and daily insulin injections. The purpose of this study is to report long-term outcomes of this procedure, and describe surgical and medical complications.

METHODS

The analysis includes 1000 consecutive SPKs performed between 1985 and 2007. Bladder drainage was used in 390 patients and enteric drainage in 610 patients. In 362 patients, SPK transplantation was performed before initiation of dialysis.

RESULTS

Patient survival at 1, 10, and 20 years is 97%, 80%, and 58%; kidney survival is 91%, 63%, and 38%; and pancreas survival is 88%, 63%, and 36%, respectively. There was no difference (P > 0.19) for patient, kidney, and pancreas survival between bladder and enteric drainage. Major surgical complications for bladder-drained patients were anastomotic leaks, urological complications, and infections. For enteric-drained patients, major surgical complications were infection, bleeding, and enzyme leak. Principal causes of death were myocardial infarction (n = 23), cerebrovascular accident (n = 18), and renal failure (n = 15). Graft failure for the kidney was due to acute rejection (n = 48), chronic rejection (n = 146), and death with a functioning graft (n = 99). Graft failure for the pancreas was caused by chronic graft loss (n = 44), thrombosis (n = 31), rejection (n = 80), and death with a functioning graft (n = 125). A total of 113 patients were retransplanted with either living related or unrelated donor kidneys (n = 64) or deceased donor kidneys (n = 42). Survival for retransplanted kidneys is 84% at 1 year and 68% at 5 years. Surviving bladder-drained patients underwent enteric conversion (>50%) for severe recalcitrant metabolic or urologic complications, most commonly enzyme leaks, hematuria, and recurrent urinary tract infection.

CONCLUSIONS

Diabetic patients with end-stage renal failure have a poor prognosis without transplantation. Transplantation with SPK provides a marked extension of the patient's life and freedom from insulin injections. Enteric drainage is currently the surgical technique of choice. SPK transplantation should be considered the treatment of choice in this patient population.

Evolution of β-Cell Replacement Therapy in Diabetes Mellitus: Pancreas Transplantation

Diabetes mellitus remains one of the leading causes of morbidity and mortality worldwide. According to the Centers for Disease Control and Prevention, approximately 23.6 million people in the United States are affected. Of these individuals, 5-10% have been diagnosed with type 1 diabetes mellitus (TIDM), an autoimmune disease. Although it often appears in childhood, T1DM may manifest at any age. The effects of T1DM can be devastating, as the disease often leads to significant secondary complications, morbidity, and decreased quality of life. Since the late 1960s, surgical treatment for diabetes mellitus has continued to evolve and has become a viable alternative to chronic insulin administration. In this review, the historical evolution, current status, graft efficacy, benefits, and complications of pancreas transplantation are explored.

Pancreas transplant: recent advances and spectrum of features in pancreas allograft pathology

As result of improved surgical techniques and newer immunosuppressive regimens contributing significantly to better graft survival, exocrine pancreas transplantation remains the standard treatment of choice for patients with diabetes mellitus complicated by end-stage renal disease. Histologic assessment continues to play an important role in the diagnosis of graft complications after pancreas transplantation, especially for evaluating allograft rejection where histopathology is still considered the gold standard. This review elaborates on the current types of pancreas transplants and focuses on the patterns of allograft injury that are encountered in posttransplantation pancreas biopsies along with the pertinent differential diagnoses. In addition to optimal histologic assessment, as in any other organ transplant setting, clinical information including indication and duration of transplant as well as other serologic work-up must be taken into consideration during clinical decision making for optimal graft outcome.

Surgical techniques for pancreas transplantation

PURPOSE OF REVIEW

Pancreas transplantation reproducibly induces insulin independence in beta-cell penic diabetic patients. The difference between full insulin independence, partial graft function, and graft loss, mostly results from technical failure, graft rejection, and patient death with function graft. The purpose of this review is to examine recent surgical advances and discuss their contribution to improved graft function.

RECENT FINDINGS

Few actual surgical innovations were described in the period reviewed. Duodenoduodenostomy is an interesting option for drainage of digestive secretions, when the pancreas is placed behind the right colon and is oriented cephalad. The main advantage of this technique is easy endoscopic assessment of donor duodenum but, when allograft pancreatectomy is necessary, repair of native duodenum may be troublesome. Selective revascularization of the gastroduodenal artery, at the back-table, possibly improves blood supply to the head of the pancreas graft and duodenal segment. There is no proof that this additional maneuver is always beneficial, although it can be graft saving in case of poor segmental graft perfusion.

SUMMARY

Transplant surgeons should be familiar with all techniques for pancreas transplantation. Long-term graft function is possible only after technically successful pancreas transplantation. There is clearly a need for more objective assessment and standardization of surgical techniques for pancreas transplantation.

Are there still roles for exocrine bladder drainage and portal venous drainage for pancreatic allografts?

PURPOSE OF REVIEW

Controversy remains regarding the best methodology of handling exocrine pancreatic fluid and pancreatic venous effluent. Bladder drainage has given way to enteric drainage. However, is there an instance in which bladder drainage is preferable? Also, hyperinsulinemia, as a result of systemic venous drainage (SVD), is claimed to be proatherosclerotic, whereas portal venous drainage (PVD) is more physiologic and less atherosclerotic.

RECENT FINDINGS

Bladder drainage remains a viable method of exocrine pancreas drainage, but evidence is sparse that measuring urinary amylase has a substantial benefit in the early detection of acute rejection in all types of pancreas transplants. Currently, there is no incontrovertible evidence that systemic hyperinsulinemia is proatherosclerotic, whereas recent metabolic studies on SVD and PVD showed that there was no benefit to PVD.

SUMMARY

Given the advent of newer immunosuppressive agents and overall lower acute rejection rates, the perceived benefit of bladder drainage as a means to measure urinary amylase as an early marker of rejection has not been substantiated. However, there may be a selective role for bladder drainage in 'high risk' pancreases. Also, without a clear-cut metabolic benefit to PVD over SVD, it remains the surgeon's choice as to which method to use.

Pancreas transplantation

Since the introduction of pancreas transplantation more than 40 years ago, efforts to develop more minimally invasive techniques for endocrine replacement therapy have been in progress, yet this surgical procedure still remains the treatment of choice for diabetic patients with end-stage renal failure. Many improvements have been made in the surgical techniques and immunosuppressive regimens, both of which have contributed to an increasing number of indications for pancreas transplantation. This operation can be justified on the basis that patients replace daily injections of insulin with an improved quality of life but at the expense of a major surgical procedure and lifelong immunosuppression. The various indications, categories, and outcomes of patients having a pancreas transplant are discussed, particularly with reference to the effect on long-term diabetic complications.

Experience with pancreatic transplantation in Stockholm

Eight attempts at segmental pancreatic transplantation were made in 6 diabetic patients. While the indications for transplantation differed all the patients were severely incapacitated by the disease. None was uremic. The body and tail of the pancreas from cadaveric donors was used, the grafts were revascularized to the recipient's iliac vessles. Six of the grafts provided control of blood glucose for 7-51 days. Five of the grafts then failed owing to rejection, and one had to be removed while still functioning, because of arterial bleeding. Important lessons have been learned concerning both surgical and immunological aspects of this form of treatment : 1) Ducto-jejunostomy should be used to provide exocrine pancreatic drainage. 2) HLA-DR typing for donor-recipient selection and thoracic-duct drainage as an adjunctive immunosuppressive measure should be used to reduce the incidence of graft rejection. 3) An elevation of the postprandial blood glucose concentration is a first sign of rejection and should cause treatment. 4) Graft rejection can be reversed by conventional steroid medication.

World's longest surviving liver-pancreas recipient

In July 1988, the liver and pancreas of a cadaveric donor were transplanted separately into a man with type 1 diabetes with end-stage chronic hepatitis B virus. Two features of the operation may help explain the patient's current status as the longest-lived liver-pancreas recipient. One was enteric drainage of pancreatic exocrine secretions. The other was delivery of the pancreas venous effluent to the host portal system and then directly to the hepatic allograft.

Immunosuppressive standards in simultaneous kidney?pancreas transplantation

Simultaneous pancreas-kidney transplantation is an established procedure for patients with type I diabetes and end-stage renal disease. Continuous advances in the operation techniques with consequent reduction of perioperative morbidity and mortality and the introduction of modern immunosuppressive agents improved not only patients but also graft survival and significantly decreased rejection episodes of both kidney and pancreas grafts. Availability of a variety of new immunosuppressants in the clinical routine and increasing experience of the transplant specialists allowed further developments of therapeutic schemes with application of induction and maintenance immunosuppressive protocols. In this article, we summarize the current status of immunosuppressive regimens in simultaneous pancreas and kidney transplantation.

Opções técnicas utilizadas no transplante pancreático em centros brasileiros

OBJETIVO: Analisar o perfil dos principais centros de transplantes do Brasil, quanto às opções técnicas no transplante de pâncreas. MÉTODO: Foi encaminhado um questionário por correio eletrônico (email) para um membro de cada equipe de 12 centros de transplante do Brasil, com casuística mínima de um transplante de pâncreas. O questionário continha 10 perguntas, abordando aspectos controversos e não padronizados. RESULTADOS: A maioria dos centros (90,9%) utiliza incisão mediana. O órgão de escolha a ser implantado primeiro foi principalmente o rim, em 63% dos centros. Em relação à drenagem venosa, 90,9% utilizam a drenagem sistêmica. A ligadura da veia ilíaca interna é realizada em 54,5% dos centros. A maioria dos centros (90,9%) utiliza a drenagem entérica para transplante combinado pâncreas-rim. Para o transplante de pâncreas isolado, apenas cinco centros responderam, sendo que dois utilizam a drenagem entérica e três a vesical. A utilização de dreno na cavidade abdominal ocorre em 63% dos centros. Em 72,7% dos centros é realizada algum tipo de indução na imunossupressão para o transplante combinado pâncreas-rim, sendo a imunossupressão básica a associação de tacrolimus (FK506), micofenolato mofetil (MMF) e corticóide. A antibioticoprofilaxia é realizada por todos os centros e profilaxia para fungos é realizada por seis centros (54,5%). Oito centros (72,7%) utilizam algum tipo de profilaxia para trombose vascular, em esquemas diversos. CONCLUSÃO: Existem diversos caminhos técnicos na condução do transplante pancreático. A falta de padronização dificulta a análise e a comparação dos resultados. Apesar dessa heterogeneidade das equipes, observamos uma tendência para a realização de incisão mediana, drenagem venosa sistêmica e exócrina entérica, com a utilização de algum tipo de profilaxia para trombose vascular nos transplantes combinados pâncreas-rim.

Advances in pancreas transplantation

Despite early obstacles impacting the success of pancreatic transplantation, the introduction of new procedures and new immunosuppressive therapies during the past 2 decades has improved outcomes for pancreatic transplant recipients. For example, the use of bladder drainage and better human leukocyte antigen matching has helped overcome some of the early obstacles of pancreatic transplantation. In addition, the introduction of tacrolimus in 1994 and mycophenolate mofetil in 1996 has helped lower rates of acute rejection and increase graft survival, with less nephrotoxicity than treatment with cyclosporine. Regimens allowing the tapering of corticosteroids have also helped reduce the rates of acute pancreas rejection. To further improve therapeutic options for patients with type 1 diabetes or end-stage renal disease, pancreatic islet transplantation and organ and islet xenotransplantation should be further explored.

Pancreas and islet cell transplantation

Currently, for the patient with type 1 diabetes, a definitive treatment without resorting to the use of exogenous insulin can be achieved only with pancreas or islet cell transplantation. These means of restoring beta-cell mass can completely maintain essentially normal long-term glucose homeostasis, although the need for powerful immunosuppressive regimens limits their application to only a subgroup of adult patients. Apart from the shortage of donors that has limited all kinds of transplantation, however, the widespread use of beta-cell replacement has been precluded until recently by the drawbacks associated with both organ and islet cell transplantation. Although the study of recurrence of diabetes has generated attention, the fundamental obstacle to pancreas and islet transplantation has been, and remains, the alloimmune response. With a better elucidation of the mechanisms of alloengraftment achieved during the last 3 years, the stage has been set for further advances.

Lessons learned from more than 1,000 pancreas transplants at a single institution

OBJECTIVE

To determine outcome in diabetic pancreas transplant recipients according to risk factors and the surgical techniques and immunosuppressive protocols that evolved during a 33-year period at a single institution.

SUMMARY BACKGROUND DATA

Insulin-dependent diabetes mellitus is associated with a high incidence of management problems and secondary complications. Clinical pancreas transplantation began at the University of Minnesota in 1966, initially with a high failure rate, but outcome improved in parallel with other organ transplants. The authors retrospectively analyzed the factors associated with the increased success rate of pancreas transplants.

METHODS

From December 16, 1966, to March 31, 2000, the authors performed 1,194 pancreas transplants (111 from living donors; 191 retransplants): 498 simultaneous pancreas-kidney (SPK) and 1 simultaneous pancreas-liver transplant; 404 pancreas after kidney (PAK) transplants; and 291 pancreas transplants alone (PTA). The analyses were divided into five eras: era 0, 1966 to 1973 (n = 14), historical; era 1, 1978 to 1986 (n = 148), transition to cyclosporine for immunosuppression, multiple duct management techniques, and only solitary (PAK and PTA) transplants; era 2, 1986 to 1994 (n = 461), all categories (SPK, PAK, and PTA), predominantly bladder drainage for graft duct management, and primarily triple therapy (cyclosporine, azathioprine, and prednisone) for maintenance immunosuppression; era 3, 1994 to 1998 (n = 286), tacrolimus and mycophenolate mofetil used; and era 4, 1998 to 2000 (n = 275), use of daclizumab for induction immunosuppression, primarily enteric drainage for SPK transplants, pretransplant immunosuppression in candidates awaiting PTA.

RESULTS

Patient and primary cadaver pancreas graft functional (insulin-independence) survival rates at 1 year by category and era were as follows: SPK, era 2 (n = 214) versus eras 3 and 4 combined (n = 212), 85% and 64% versus 92% and 79%, respectively; PAK, era 1 (n = 36) versus 2 (n = 61) versus 3 (n = 84) versus 4 (n = 92), 86% and 17%, 98% and 59%, 98% and 76%, and 98% and 81%, respectively; in PTA, era 1 (n = 36) versus 2 (n = 72) versus 3 (n = 30) versus 4 (n = 40), 77% and 31%, 99% and 50%, 90% and 67%, and 100% and 88%, respectively. In eras 3 and 4 combined for primary cadaver SPK transplants, pancreas graft survival rates were significantly higher with bladder drainage (n = 136) than enteric drainage (n = 70), 82% versus 74% at 1 year (P =.03). Increasing recipient age had an adverse effect on outcome only in SPK recipients. Vascular disease was common (in eras 3 and 4, 27% of SPK recipients had a pretransplant myocardial infarction and 40% had a coronary artery bypass); those with no vascular disease had significantly higher patient and graft survival rates in the SPK and PAK categories. Living donor segmental pancreas transplants were associated with higher technically successful graft survival rates in each era, predominately solitary (PAK and PTA) in eras 1 and 2 and SPK in eras 3 and 4. Diabetic secondary complications were ameliorated in some recipients, and quality of life studies showed significant gains after the transplant in all recipient categories.

CONCLUSIONS

Patient and graft survival rates have significantly improved over time as surgical techniques and immunosuppressive protocols have evolved. Eventually, islet transplants will replace pancreas transplants for suitable candidates, but currently pancreas transplants can be applied and should be an option at all stages of diabetes. Early transplants are preferable for labile diabetes, but even patients with advanced complications can benefit.

History of clinical transplantation

The emergence of transplantation has seen the development of increasingly potent immunosuppressive agents, progressively better methods of tissue and organ preservation, refinements in histocompatibility matching, and numerous innovations in surgical techniques. Such efforts in combination ultimately made it possible to successfully engraft all of the organs and bone marrow cells in humans. At a more fundamental level, however, the transplantation enterprise hinged on two seminal turning points. The first was the recognition by Billingham, Brent, and Medawar in 1953 that it was possible to induce chimerism-associated neonatal tolerance deliberately. This discovery escalated over the next 15 years to the first successful bone marrow transplantations in humans in 1968. The second turning point was the demonstration during the early 1960s that canine and human organ allografts could self-induce tolerance with the aid of immunosuppression. By the end of 1962, however, it had been incorrectly concluded that turning points one and two involved different immune mechanisms. The error was not corrected until well into the 1990s. In this historical account, the vast literature that sprang up during the intervening 30 years has been summarized. Although admirably documenting empiric progress in clinical transplantation, its failure to explain organ allograft acceptance predestined organ recipients to lifetime immunosuppression and precluded fundamental changes in the treatment policies. After it was discovered in 1992 that long-surviving organ transplant recipients had persistent microchimerism, it was possible to see the mechanistic commonality of organ and bone marrow transplantation. A clarifying central principle of immunology could then be synthesized with which to guide efforts to induce tolerance systematically to human tissues and perhaps ultimately to xenografts.

Historic landmarks in clinical transplantation: conclusions from the consensus conference at the University of California, Los Angeles

The transplantation of organs, cells, and tissues has burgeoned during the last quarter century, with the development of multiple new specialty fields. However, the basic principles that made this possible were established over a three-decade period, beginning during World War II and ending in 1974. At the historical consensus conference held at UCLA in March 1999, 11 early workers in the basic science or clinical practice of transplantation (or both) reached agreement on the most significant contributions of this era that ultimately made transplantation the robust clinical discipline it is today. These discoveries and achievements are summarized here in six tables and annotated with references.

Duodenal segment complications in vascularized pancreas transplantation

Bladder drainage by the duodenal segment (DS) technique is currently the preferred method of pancreas transplantation (PTX) but is associated with unique complications. Over a 7-year period, 191 diabetic patients underwent 201 whole-organ PTXs with bladder drainage using a 6 to 8 cm length of DS as an exocrine conduit. A retrospective chart review was performed to document all DS morbidity. DS complications occurred in 38 cases (19%). Twelve patients developed DS leaks and required operative repair. DS bleeding was documented in 26 cases, necessitating cystoscopy in 22 patients and open repair in eight patients for significant hematuria. Cytomegalovirus (CMV) duodenitis was diagnosed in seven cases, with four presenting as DS leaks and three with hematuria. Five patients experienced ampullary obstruction early after PTX. Rejection of the DS was confirmed by biopsy in 13 patients, including eight cases of acute and five cases of chronic rejection. Two patients had stone formation from the DS staple line. Enteric conversion was performed in five patients for DS abnormalities (leaks in 2 cases, bleeding in 2, and CMV duodenitis in 1). Among patients with DS complications, patient survival is 84% and pancreas graft survival is 68% after a mean follow-up of 44+/-12 months. Complications related to the DS remain an important source of morbidity but rarely cause death after PTX. In spite of unique side effects, transplantation of the DS remains an acceptable alternative for exocrine drainage after PTX.

Experimental pancreas transplantation: the consequences of the portocaval shunt on the blood glucose, plasma insulin, and glucagon

The consequences of the bypass of the portal venous effluent into the systemic circulation on the blood glucose, plasma insulin, and glucagon in immediate postoperative period of rats submitted to pancreas transplantation were studied. Forty outbred male Wistar rats were randomly assigned to two experimental groups: group NC included 20 non-diabetic control rats, submitted to simulated operating (sham-operated), and group PT included 20 diabetic rats that received heterotopic pancreas transplantation from normal donor Wistar rats. For 7 days prior and 1, 3, 6, 12, 24, 48, 72 and 96 hours after transplantation blood glucose, plasma insulin, and glucagon were recorded. These parameters were also concurrently recorded for NC rats. Diabetes was induced by i.v. alloxan administration; PT rats were immunosuppressed with cyclosporin A. NC rats presented normal values of blood glucose, plasma insulin, and glucagon over the course of experiment. A marked hyperinsulinemia was found in peripheral venous blood of PT rats, being plasma insulin significantly higher than that for NC rats (P<0.01) beginning 72- h after transplant. The plasma glucagon, elevated in pre-transplant period, did not change after transplant. Despite hyperinsulinemia and hyperglucagonemia, the blood glucose levels were elevated up to 6- h after transplant, but were within normal levels following this period. Beginning at 12- h after transplant the blood glucose levels observed in PT rats did not differ significantly to NC rats until the sacrifice.