Pancreatic duct to ureter anastomosis for exocrine drainage in pancreatic transplantation

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.

[Diabetes Type I therapy through transplantation]

Diabetes is one of the most common chronic diseases in our society. While insulin treatment for diabetes type I could delay and reduce the incidence of diabetic complications, it is associated with an increased risk of severe hypoglycemia. To restore physiologic insulin metabolism, transplantation of insulin producing cells (pancreatic Beta cells) represent the sole available therapy. It could be done either through pancreas or islet of Langerhans transplantation. In this paper, we review actual knowledge regarding these two types of transplantations.

[Pancreatic Transplantation: 2. Surgical technique and post-operative complications]

Since the first pancreatic allograft in 1966, pancreatic transplantations have been performed by numerous surgical teams throughout the world. Initial results were disappointing with a high percentage of technical failures and rejection. Over-optimistic enthusiasm for islet-cell allografts also retarded the development of pancreatic transplantation. Despite this slow start, results of pancreatic transplantation from 1995 onward have been very satisfactory and equivalent to or even better than the results of other solid organ transplants. This success has been due to better graft selection, improved surgical techniques and preservation solutions, and especially to improvements in immunosuppressive protocols. More than 19,000 pancreatic transplantations have now been performed throughout the world including both combined kidney-pancreas transplantations and pancreas-only transplantations. The most satisfactory results occur in the setting of dialysis-dependent renal failure due to diabetes; simultaneous combined kidney and pancreas transplantation is performed with the total pancreas implanted into the bowel and with venous drainage into the portal system. The long-term risks and constraints of chronic diabetes with renal failure must be weighed against the risks of a complex surgical procedure, significant post-operative complications, and the need for long-term immunosuppressive therapy.

Vascularized pancreas allotransplantation--clinical indications and outcome

AIMS

This review examines the status of vascularized pancreas transplantation as a treatment for Type 1 diabetes mellitus (DM).

METHODS

The world literature, with a particular emphasis on data from the International Pancreas Transplant Registry (IPTR), is reviewed and interpreted particularly for clinical indications and outcome.

RESULTS

Over 9000 cases of vascularized pancreas transplant (VPT) have been registered, with insulin dependence approaching 82% at 1 year with 94% patient survival. The majority of transplants are simultaneous pancreas and kidney (SPK) transplants, with far fewer pancreas after kidney (PAK) or pancreas transplants alone (PTA). The success rates differ between the procedures but are generally improving as technical advances, improvements in immunosupression and greater experience are gained. The most obvious advantage is an improved quality of life (QoL) but there are risks associated with the procedure and with the immunosuppression. There is some evidence coming to light of a very slow beneficial effect on microvascular complications.

CONCLUSIONS

VPT is an attractive option to offer Type 1 DM patients who need or already have a renal allograft. Patients have to decide between the increased surgical risk and the risks of long-term immunosuppression and the benefits of improved QoL. In the absense of end-stage renal failure (ESRF) there is no justification for PTA, except where the diabetes itself poses a greater risk to life than the transplantation procedure.

Pancreas transplantation

Although intensified insulin therapy regimens enable normalization of blood glucose levels and related metabolic parameters, these regimens are associated with an increased incidence of hypoglycemic episodes. Pancreas transplantation has achieved the goal of providing insulin independence with stable and continuous normoglycemia. But because of the associated morbidity and mortality and the need for life-long immunosuppression after transplant, it is difficult to justify pancreas transplantation in diabetic patients at a pre-uremic stage. Pancreas transplantation is therefore performed in conjugation with renal transplantation. The majority of renal transplant centers, however, have been reluctant to perform simultaneous kidney-pancreas transplantation in insulin-dependent uremic patients because of the additional risks associated with pancreas transplantation. More recently, refinements in surgical technique, introduction of new immunosuppressive agents, and better selection of transplant candidates have contributed to improved survival. Today, combined pancreas-kidney transplantation is an accepted treatment for carefully selected patients with insulin dependent diabetes and end-stage renal disease and in a small group of patients with uncontrolled severe metabolic problems. The effect of a euglycemic state after pancreas transplantation on the progression of micro- and macroangiopathy remains to be proved, although recently there is evidence to suggest that some end-organ lesions may be halted or even ameliorated. Further improvement in anti-rejection strategies may achieve better long-term graft survival and provide the incentive to perform pancreas transplantation at an earlier stage, before severe secondary complications of diabetes develop.

Conversion from bladder to enteric drainage after pancreaticoduodenal transplantations

BACKGROUND

Bladder drainage is the most common technique for managing the exocrine secretions of pancreaticoduodenal grafts. However, bladder drainage can cause urinary, pancreatic, and metabolic complications that may require conversion to enteric drainage. With enteric drainage, urinary amylase levels cannot be monitored as a marker for rejection. After enteric conversion, rejection is the major cause of graft loss. Timing the conversion to reduce immunologic graft loss would greatly improve patient and graft survival rates. Our study was designed to assess the incidence of, indications for, and complications of converting from bladder to enteric drainage after pancreaticoduodenal transplantations.

METHODS

We retrospectively reviewed our experience with 80 recipients who underwent enteric conversion. We studied the recipient category, the interval from transplantation to conversion, the interval from the last rejection episode to conversion, the indications for conversion, the type of enteric drainage at conversion (loop versus Roux-en-Y), the results of the conversion, and postconversion complications.

RESULTS

The major indications for conversion were metabolic acidosis (n = 26, 33%), recurrent urinary tract infections (UTIs) (n = 16, 20%), reflux pancreatitis (n = 15, 19%), and hematuria (n = 12, 15%). For most recipients, their symptoms resolved after conversion (n = 76, 95%). The cumulative probability of undergoing conversion was 13% at 12 months, 21% at 36 months, and 25% at 60 months. Of the recipients with surgical complications after conversion (n = 12, 15%), one lost his graft as a result of pancreatitis. Overall, of the 80 recipients who underwent conversion, 12 (15%) lost their graft, most due to rejection (n = 8, 75%). Immunologic graft loss was highest for recipients of pancreas transplants alone who underwent conversion < or = 6 months after transplantation or < or = 1 year after their last rejection episode.

CONCLUSIONS

Enteric conversion is safe and therapeutic in recipients with complications related to the exocrine secretions of bladder-drained pancreas grafts. After conversion, rejection accounted for 75% of the grafts lost. However, waiting at least 1 year after the last rejection episode significantly reduced immunologic graft loss.

Urological complications of pancreatic transplantation

PURPOSE

Pancreas transplantation is increasingly being used in the treatment of type I insulin-dependent diabetes mellitus. Because bladder drainage of the exocrine pancreatic secretion is the procedure of choice, urological complications are frequent. As the number of these procedures increases the urologist will have an extended role in the management of the postoperative complications, the majority of which are urological.

MATERIALS AND METHODS

The literature from 1985 on the complications related to pancreas transplants was reviewed.

RESULTS

Approximately 50 to 60% of bladder drained pancreas transplant recipients will have a urological complication postoperatively.

CONCLUSIONS

The increasing application of bladder drained pancreas transplantation in the treatment of type I insulin-dependent diabetes mellitus necessitates that the clinical urologist is familiar with the management of complications related to this procedure.

Pancreas transplantation and dysuria

Bladder drainage of the pancreatic graft remains the most common technique in pancreatic transplantation. Graft and patient survival is superior to duct injection and bowel drainage techniques. However, several urological complications develop as a result of bladder drainage. We report 6 cases of the dysuria syndrome after combined kidney/pancreas transplantation. Retrograde urethrography or cystoscopy showed extravasation from the bulbous urethra in all cases, which was most likely caused by activated proteolytic exocrine enzymes from the transplanted pancreas. Minor urethral trauma due to Foley catheterization or cystoscopy may predispose patients to this syndrome. Short-term urethral catheterization or suprapubic catheter drainage led to resolution in all cases. A high index of suspicion coupled with early intervention is recommended for patients with the dysuria syndrome.

Urological complications in 210 consecutive simultaneous pancreas-kidney transplants with bladder drainage

OBJECTIVE

The urological complications of 210 patients who underwent simultaneous pancreas-kidney (SPK) transplantation over a 7-year period were reviewed.

SUMMARY BACKGROUND DATA

Worldwide, bladder drainage has become the accepted method of exocrine drainage after pancreas transplantation. With the increasing use of bladder drainage, the surgical post-transplant complications have shifted from intra-abdominal complications to urological complications.

METHODS

Two hundred ten diabetic patients received SPK transplants with bladder drainage. A retrospective review was conducted to analyze the incidence, type, and management of urological complications.

RESULTS

The most frequent urological complications were hematuria, leak from the duodenal segment, recurrent urinary tract infections, urethritis, and ureteral stricture and disruption. Complications related to the renal transplant included ureteral stricture and leaks, as well as lymphoceles.

CONCLUSIONS

Despite the high incidence of urological complications, 5-year actuarial patient and graft survival are excellent. Only one graft and one patient were lost secondary to urological complications.

Comparison of graft morphology and endocrine function after vascularized whole-pancrease transplantation in the rat by different surgical techniques

Graft morphology and endocrine function following vascularized pancreas transplantation by different surgical techniques were determined in streptozotocin-diabetic rats. Eight different surgical techniques were studied. Intestinal drainage of exocrine secretion was accomplished by pancreaticoduodenal transplantation or by utilizing only a patch of the donor duodenum for duodenojejunostomy. Following pancreaticoureterostomy and pancreaticocystostomy, the graft's exocrine secretion was drained to the recipient's urinary tract. The exocrine secretion was allowed to drain freely into the recipient's peritoneal cavity following transverse or longitudinal incision of the common bile duct. Exocrine secretion was suppressed either by duct ligation or by retrograde ductal injection of prolamine. Following enteric or urinary exocrine graft drainage, the architecture of both the endocrine and exocrine pancreas was perfectly preserved. Pancreatic juice had remarkably few adverse effects on the recipient's urinary tract. Obstruction of the exocrine secretion induced atrophy of the acinar cells, proliferation of small pancreatic ducts, and a typical fragmentation of the islets of Langerhans. Prolamine was biologically degraded within 28 days. Following free intraperitoneal drainage, spontaneous suppression of the exocrine graft function occurred early after transplantation. Metabolic signs of diabetes mellitus including hypoinsulinemia, hyperglycemia, polydipsia, polyuria, and impaired glucose tolerance were completely normalized by pancreas transplantation irrespective of the surgical technique used. Despite fundamental differences in graft architecture no alteration of endocrine graft function was noted following vascularized pancreas transplantation by different surgical techniques.

Metabolic effect of pancreas transplantation on long-term diabetic rats

Thirty-six male Lewis rats rendered diabetic using alloxan received syngeneic pancreaticoduodenal grafts. Seven days prior to and 7, 30, and 90 days posttransplantation, the animals were housed in metabolic cages for periods of 48 hours. During this time, body weight, water intake, food intake, urine output, and fecal output were recorded every 24 hours. Blood sugar, plasma insulin, glucosuria, and proteinuria were determined at 3-month intervals prior to the transplant and at monthly intervals posttransplantation. These parameters were also concurrently recorded for diabetic control rats. Pancreaticoduodenal transplantation produces immediate relief of hyperglycemia, glucosuria, polyuria, polyphasia, and polydypsia, resulting in good health of the animals until the time of sacrifice. A significantly increased insulin level was also recorded. The transplanted animals showed a weight gain reflecting that of a normal growth curve.

Physiologic studies of urinary drained pancreaticoduodenal grafts in humans

Exocrine function of urinary drained pancreas transplants (UDP) as determined by measurements of urinary pancreatic metabolites was assessed in 15 recipients. Normal UDP showed significantly higher levels (P less than 0.05) of urinary amylase, (42,931 +/- 5135 U/liter), HCO3 (27.12 +/- 3.18 meq/liter), and pH 7.83 +/- 0.15) than nine other recipients of enteric drained pancreas transplants with corresponding values of 168.00 +/- 2.00 U/liter, 3.20 +/- 0.20 meq/liter, and 6.08 +/- 0.27. These urinary metabolites dropped significantly (P less than 0.02) during rejection to 13,576 +/- 3446 U/liter, 19.22 +/- 5.74 meq/liter, and 7.06 +/- 0.14, respectively. These changes preceded elevation of blood sugar levels by 2-3 days. During rejection episodes, pancreatic grafts failed also to excrete bicarbonate and amylase significantly in response to secretion stimulation (P less than 0.05) contrary to nonrejecting pancreata. It is concluded that decreases in urinary amylase, HCO3, and pH observed with and without secretin stimulation are simple markers of pancreatic rejection.

Canine whole pancreatic transplantation with exocrine drainage into the bladder

A canine model of whole pancreas transplantation with pancreaticocystostomy was studied for reproducibility and long-term graft function with oral cyclosporine. The feasibility of the operative technique was established in three dogs and the graft histology at 5 days was studied. Seven pancreatectomized dogs were transplanted without immunosuppression; acute rejection was evident at a median of 10 days (range: 7-12 days). Another 14 non-pancreatectomized dogs were given oral cyclosporine (25 mg/kg per day) resulting in prolonged graft survival (P less than 0.01) with a median (actuarial) survival of 91 days (range: 8-159 days); five dogs had vascular thrombosis or graft rejection and eight dogs died with functioning grafts. Early technical loss in two dogs (8.3%) was due to arterial thrombosis. It is concluded that the model of whole pancreas transplantation was reproducible in dogs, that long-term graft function can be achieved on oral cyclosporine, and that duct patency can be maintained. Graft infarction, either primary or due to rejection, continues to complicate this model of pancreas transplantation.

Evaluation of cryopreservation techniques of pancreatic fragments and islets in vitro and in vivo

We evaluated cryopreservation techniques for pancreatic fragments and islets using rat tissue. After equilibration in 10% dimethyl sulfoxide (Me2SO), the tissue was frozen in a programmable freezer at 1 degree C/min down to -40 degrees C and at 3 degrees C/min down to -71 degrees C. The islets, when thawed, released abundant insulin in the presence of as little as 3.3 mM glucose, much more so than non-frozen islets did. Three additional procedures, prefreezing and post-thawing culture and the stepwise dilution of the Me2SO, lowered the non-specific insulin release of the thawed islets and improved their insulin response to 16.7 mM glucose. Thawed pancreatic fragments subjected to these additional procedures, transplanted into the peritoneal cavity of streptozotocin-induced diabetic rats, reduced their hyperglycemia significantly. The thawed fragments and islets did not differ from their corresponding non-frozen controls in 3H-leucine incorporation. The maintenance of tissue function was not satisfactory. However, our observations indicate that culturing pancreatic tissue before freezing and after thawing and the stepwise dilution of the cryoprotective agent reduce the damage induced by freezing the tissue.

Long-term studies of pancreas allotransplantation in experimental diabetes mellitus

Pancreaticoduodenal (PD) allografts (Brown Norway-alloxan-diabetic rats, n = 190) were treated with cyclosporin A (Cy-A) 10 mg/kg/daily and compared with nondiabetics with Cy-A treatment (n = 55), diabetics (n = 50), and diabetics with Cy-A treatment (n = 45). Body weight, blood sugar, blood insulin, blood urea nitrogen (BUN), and creatinine were monitored periodically; there were marked elevations of BUN and creatinine levels, indicating probably nephrotoxicity of Cy-A at this dosage. Some islet cell atrophy in the PD allografts was noted at the conclusion of the study. With respect to the immunosuppressive effect of Cy-A in alloxan diabetic rats, Brown Norway PD transplants into Lewis rats were successful and free of rejection for as long as 15 months post-transplantation. The body weight of these PD transplanted rats, however, never approached values representative of the nondiabetic rats. In our experience, the PD allograft model is acceptable in the clinical situation, particularly in children if the microsurgical technique is mastered and if the Cy-A regimen is used in combination with other immunosuppressant(s).

One hundred pancreas transplants at a single institution

Clinical pancreas transplantation at the University of Minnesota began in 1966. An initial series of 14 whole pancreas grafts was reported in part to the American Surgical Association in 1970. Only one patient survived for more than 1 year with a functioning graft. Twenty attempts at islet allotransplantation in the mid-1970s were unsuccessful. In 1978 we resumed performing pancreas transplants by the segmental technique, allowing the use of related donors. The current series (July 25, 1978 to December 20, 1983) includes 86 pancreas transplants (51 cadaver, 35 related) in 75 patients (41 with and 34 without previous kidney grafts). Variations in management of the pancreatic duct include three ligated, 15 duct-open, 39 duct-injected, and 29 pancreaticojejunostomies. The latter technique is currently preferred. Currently (April 1984) 61 patients are alive (81%), 24 have functioning grafts (32%), and 21 are insulin-independent (28%), three with open-duct grafts for 4.4 to 5.7 years, seven with silicone-injected grafts from 10 to 39 months, and 14 with pancreaticojejunostomies for 3 to 31 months; 15 of the grafts have functioned for greater than 1 year. Twenty-two of the grafts (25%) failed for technical reasons (thrombosis, infection, or ascites); 35 grafts functioned for 1 to 13 months before totally failing from either rejection, fibrosis, or recurrent disease; five patients died with functioning grafts. The graft survival rate has been higher for pancreases from related (15/35, 43% functioning) than from cadaver (9/51, 18% functioning) donors. The success rate has increased, e.g., 11/22 recipients of pancreas transplants in 1983 currently have functioning grafts (50%). Metabolic studies show most patients with functioning grafts to be euglycemic; however, three of 24 have chronic hyperglycemia unless supplemented with insulin, but they are no longer ketosis-prone. Glucose tolerance test results are normal or nearly normal in 12 and abnormal in 12 of the recipients with currently functioning grafts. Regression of diabetic nephropathy has been documented in two long-term recipients. Pancreas transplantation is currently applicable as treatment for selected diabetics who have demonstrated their propensity to develop serious secondary complications.

Total pancreatectomy in dogs

Total pancreatectomy in dogs has been an important laboratory maneuver for studies of the apancreatic state and transplantation. The shared blood supply of the pancreas and duodenum has been difficult to address surgically in a way which would preserve the duodenum. A duodenal branch of the gastroduodenal artery has been identified which can support the duodenum when the pancreaticoduodenal arcade is resected. Preservation of this artery in 80 dogs permitted complete pancreatectomy with minimal blood loss and allowed resection of the pancreaticoduodenal vessels. Preservation of the blood supply to the pancreas until the very end of the procedure was rewarded by excellent viability of the tissue. A few technical considerations make this a rather simple procedure which is easily taught. The postoperative management of apancreatic animals is greatly facilitated by utilizing this minimally traumatic procedure which has negligible blood loss.

Segmental pancreas transplantation in the canine model. A reappraisal

Segmental vascularized grafts of pancreatic tissue have been recommended in the treatment of juvenile onset insulin-dependent diabetes mellitus. The method of intraperitoneal placement and unligated pancreatic duct provided a low incidence of exocrine complications, but clinical results were less than ideal. To further assess this technique, we used segmental pancreatic autografts in the canine model. Five of the 22 dogs survived with good function of the autograft as determined by glucose homeostasis and a slow return to normal of serum amylase levels. In 12 dogs, however, pancreatic dysfunction was evident within 24 hours and death followed within days. At reexploration or necropsy, necrotic pancreatic tissue and clotted vessels were found. We suggest from these findings that although few, if any, complications of exocrine drainage or endocrine function were encountered, a major technical problem with segmental pancreatic transplantation may involve inadequate arterial runoff to maintain patency of vessels and viability of the graft. Terminal arteriovenous fistulas do not seem to improve vascular patency in the canine model in our experience.

Long-term function of duct-ligated and free-duct whole pancreas transplants

This report compares endocrine and exocrine responses of "free-duct" and "duct-ligated" whole pancreas isografts in Lewis diabetic rats during a 1-year period of observation. Fasting blood sugar, serum amylase, serum insulin, pancreozymin-secretin test, and L-arginine tolerance test assays were performed prior to and at periodic intervals after transplantation. Histological examinations of transplanted and native pancreas were performed monthly on animals in each group. Whole pancreas transplantations led to immediate and sustained normalization of FBS and insulin levels. In the "duct-ligated" group there was a gradual but insignificant decrease of serum insulin levels after 9 months. Depressed serum amylase levels in diabetic rats were reversed in both groups. Isolated islet iso- and allografts also reversed depressed amylase levels. The results of pancreozymin-secretin tests in islet isografted animals supported the postulated trophic effect of endocrine pancreas on exocrine pancreas. Although both whole-pancreas transplant groups showed a normal response to GTT for 12 months after transplantation, the "duct-ligated" group showed a significantly lower response to L-arginine tolerance test than the "free duct" model as early as 4 months after transplantation, suggesting a defect in B-cell function in long-term "duct-ligated" graft. Serial histological examinations of transplanted pancreases revealed more rapid atrophy and more intense fibrosis of acinar tissue in the "duct-ligated" group than in the "free duct" group. These results suggest that a "free duct" pancreatic isograft maintains a more stable endocrine function in a long-term study than does the "duct-ligated" pancreas, and that exocrine dysfunction in diabetic rats may be related to the endocrine disorder which can be reversed by both islet cell and whole-organ pancreatic transplantation.

Successful outcome of segmental human pancreatic transplantation with enteric exocrine diversion after modifications in technique

Segmental pancreatic transplantation is now the most widely favoured form of pancreatic transplantation, but the major difficulty with this procedure is the handling of the exocrine secretion. The use of a pancreaticoenteric anastomosis for exocrine diversion has been re-evaluated and several ancillary measures to reduce the risk of fistula and bacterial contamination have been applied. In three consecutive patients there have been no complications related to the exocrine pancreas. The pancreatic and renal grafts of these patients are functioning well 7, 3, and 2 months, respectively, after transplantation.

Histopathological studies of kidney and bladder after ileovesical diversion in dogs

The histopathological changes in bladder and kidneys after diversion of the contents of the small intestine to the urinary bladder were studied in 8 mongrel dogs, 6 to 48 months postoperatively. The bladder showed a moderate inflammatory reaction, a slight hyperplasia of the epithelium, and a slight to moderate submucosal fibrosis. These changes did not seem to grow worse with increasing observation time. These results indicated that there were no major risks for progressive bladder contraction. Renal pelvises showed mild chronic inflammation and slight fibrous thickening of the wall. Localized pyelonephritic scarring was observed in one out of 10 kidneys, the other 9 being normal.

Comparative evaluation of pancreas transplantation techniques

Three operative techniques for pancreatic transplantation have been compared: pancreaticoduodenal, pancreatic duct-jejunostomy and pancreatic duct-ureterostomy. There were no significant differences in results among these techniques when the autotransplant model was used. The pancreatic duct anastomosis without duodenum probably offers more advantages in the allograft recipient.

Transplantation of the pancreas into a retroperitoneal jejunal loop

A new technic of pancreatic transplantation was developed and assessed in sixty-nine dog experiments. The body and tail of the pancreas were transplanted into the side of the Roux-en-Y retroperitoneal limb of jejunum. A dual venous anastomosis of the splenic vein to the vena cava was utilized to avoid venous congestion. Mean survival with normoglycemia was 32.4 days in thirty dogs with autografts and 24.6 days in twenty-seven dogs with allografts. Two dogs with autotransplants remain alive at 106 and 128 days, and the longest normoglycemic survival achieved with an allograft was 85 days. With experience the incidence of pancreatitis and abscess formation decreased. The problem of venous thrombosis was eliminated and the patency of the pancreatic duct was maintained.