Prediction of pancreatic tissue densities by an analytical test gradient system before purification maximizes human islet recovery for islet autotransplantation/allotransplantation

PRISM: A Novel Human Islet Isolation Technique

BACKGROUND

Successful pancreatic islet isolations are a key requirement for islet transplantation in selected patients with type 1 diabetes. However, islet isolation is a technically complex, time-consuming, and manual process. Optimization and simplification of the islet isolation procedure could increase islet yield and quality, require fewer operators, and thus reduce cost.

METHODS

We developed a new, closed system of tissue collection, washing, buffer change, and islet purification termed PancReatic Islet Separation Method (PRISM). In the developmental phase, pump and centrifuge speed was tested using microspheres with a similar size, shape, and density as digested pancreatic tissue. After optimization, PRISM was used to isolate islets from 10 human pancreases.

RESULTS

Islet equivalents viability (fluorescein diacetate/propidium iodide), morphology, and dynamic glucose-stimulated insulin secretion were evaluated. PRISM could be performed by 1 operator in 1 flow cabinet. A similar islet yield was obtained using PRISM compared to the traditional islet isolation method (431 234 ± 292 833 versus 285 276 ± 197 392 islet equivalents, P = 0.105). PRISM islets had similar morphology and functionality.

CONCLUSIONS

PRISM is a novel islet isolation technique that can significantly improve islet isolation efficiency using fewer operators.

Total Pancreatectomy with Autologous Islet Cell Transplantation-The Current Indications

Total pancreatectomy is a major complex surgical procedure involving removal of the whole pancreatic parenchyma and duodenum. It leads to lifelong pancreatic exocrine and endocrine insufficiency. The control of surgery-induced diabetes (type 3) requires insulin therapy. Total pancreatectomy with autologous islet transplantation (TPAIT) is performed in order to prevent postoperative diabetes and its serious complications. It is very important whether it is safe and beneficial for patients in terms of postoperative morbidity and mortality, and long-term results including quality of life. Small duct painful chronic pancreatitis (CP) is a primary indication for TPAIT, but currently the indications for this procedure have been extended. They also include hereditary/genetic pancreatitis (HGP), as well as less frequent indications such as benign/borderline pancreatic tumors (intraductal papillary neoplasms, neuroendocrine neoplasms) and "high-risk pancreatic stump". The use of TPAIT in malignant pancreatic and peripancreatic neoplasms has been reported in the worldwide literature but currently is not a standard but rather a controversial management in these patients. In this review, history, technique, indications, and contraindications, as well as short-term and long-term results of TPAIT, including pediatric patients, are described.

Pancreatic Islet Purification from Large Mammals and Humans Using a COBE 2991 Cell Processor versus Large Plastic Bottles

The islet purification step in clinical islet isolation is important for minimizing the risks associated with intraportal infusion. Continuous density gradient with a COBE 2991 cell processor is commonly used for clinical islet purification. However, the high shear force involved in the purification method using the COBE 2991 cell processor causes mechanical damage to the islets. We and other groups have shown human/porcine islet purification using large cylindrical plastic bottles. Shear stress can be minimized or eliminated using large cylindrical plastic bottles because the bottles do not have a narrow segment and no centrifugation is required during tissue loading and the collection processes of islet purification. This review describes current advances in islet purification from large mammals and humans using a COBE 2991 cell processor versus large cylindrical plastic bottles.

Excellent Islet Yields after 18-h Porcine Pancreas Preservation by Ductal Injection, Pancreas Preservation with MK Solution, Bottle Purification, and Islet Purification Using Iodixanol with UW Solution and Iodixanol with MK Solution

Successful islet isolation is the key to successful islet transplantation. Our group recently modified the islet isolation protocol to include pancreatic ductal injection of the preservation solution, pancreas storage in modified extracellular-type trehalose-containing Kyoto (MK) solution, and use of an iodixanol-based purification solution and bottle purification. In this study, we applied these methods to porcine islet isolation after 18-h pancreas preservation and compared two solutions with different compositions in bottle purification. Islet yield before purification was 651,661 ± 157,719 islet equivalents (IE) and 5576 ± 1538 IE/g pancreas weight. An IU solution was made by adding iodixanol to University of Wisconsin solution and an IK solution was made by adding iodixanol to MK solution. The efficacy of the two solutions for islet isolation was compared. There were no significant differences between the two purification methods with regard to islet yield, survival rate, purity, score, or stimulation index. These results indicate that our isolation protocol produces efficient islet yields from prolonged cold-stored pancreas and that IU and IK solutions are equally useful for islet purification.

Current state and future evolution of pancreatic islet transplantation

Pancreatic islet transplantation provides an effective treatment option for patients with type 1 diabetes (T1D) with intractable impaired awareness of hypoglycemia and severe hypoglycemic events. Currently, the primary goal of islet transplantation should be excellent glycemic control without severe hypoglycemia, rather than insulin independence. Islet transplant recipients were less likely to achieve insulin independence, whereas solid pancreas transplant recipients substantially had greater procedure-related morbidity. Excellent therapeutic effects of islet transplantation as a result of accurate blood glucose level-reactive insulin secretion, which cannot be reproduced by current drug therapy, have been confirmed. Recent improvement of islet transplantation outcome has been achieved by refinement of the pancreatic islet isolation technique, improvement of islet engraftment method, and introduction of effective immunosuppressive therapy. A disadvantage of islet transplantation is that donors are essential, and donor shortage has become a hindrance to its development. With the development of alternative transplantation sites and new cell sources, including porcine islet cells and embryonic stem/induced pluripotent stem (ES/iPS)-derived β cells, "On-demand" and "Unlimited" cell therapy for T1D can be established.

Comparison of Tissue Loading Before and After the Creation of a Continuous Density Gradient in Porcine Islet Purification

The purification step is one of the most important and difficult procedures in islet isolation for pancreatic islet transplantation. We previously reported that a purification method using large plastic bottles effectively achieved a high yield of islets from the porcine pancreas. In this study, we evaluated the impact of the timing of tissue loading on porcine islet purification using large plastic bottles. One method involved loading digested tissue after creating a continuous density gradient (tissue after gradient [TAG]). The other method involved loading digested tissue before creating a continuous density gradient (tissue before gradient [TBG]). There were no significant differences between TAG and TBG in terms of the islet yield, rates of viability and purity, score, and in the stimulation index after purification. Furthermore, there were no marked differences in the attainability or suitability of post-transplantation normoglycemia. Our study shows the equivalency of these two methods of islet purification.

A Comparison of Pancreatic Islet Purification using Iodixanol with University of Wisconsin Solution and with Na-Lactobionate and Histidine Solution

Purification of pancreatic islets is an important step in islet isolation for islet transplantation. In this study, to investigate how a solution composed mainly of Na-lactobionate and histidine (HL) influences the purification of islets, iodixanol was added to a purified solution for porcine islet isolation. A solution (IU) made by adding iodixanol to University of Wisconsin solution and a solution (IHL) made by adding iodixanol to HL solution were used to evaluate the islet isolation performance. We noted no significant differences between the two purification methods with regard to the islet yield, survival rate or purity, score, or stimulation index. These results show that IHL solution is as useful as IU solution for islet purification.

Evaluation of Islet Purification Methods for Making a Continuous Density Gradient and Loading Tissue

Islet purification is one of the most important steps of islet isolation for pancreatic islet transplantation. We previously reported that a purification method using large plastic bottles effectively achieved a high yield of islets from porcine pancreas. In this study, we evaluated the methods for making a continuous density gradient and loading tissue. One method involved loading digested tissue on top of a continuous density gradient (top loading). The other method involved mixing digested tissue with low-density solution and then making a continuous gradient (mixed loading). There were no significant differences between the 2 purification methods in terms of the islet yield, rate of viability or purity, score, or in the stimulation index after purification. Furthermore, there were no marked differences in the attainability or suitability of posttransplantation normoglycemia. Our study shows the equivalency of these 2 methods of islet purification.

Operative management of chronic pancreatitis: A review

BACKGROUND

Pain secondary to chronic pancreatitis is a difficult clinical problem to manage. Many patients are treated medically or undergo endoscopic therapy and surgical intervention is often reserved for those who have failed to gain adequate pain relief from a more conservative approach.

RESULTS

There have been a number of advances in the operative management of chronic pancreatitis over the last few decades and current therapies include drainage procedures (pancreaticojejunostomy, etc.), resection (pancreticoduodenectomy, etc.) and combined drainage/resection procedures (Frey procedure, etc.). Additionally, many centers currently perform total pancreatectomy with islet autotransplantation, in addition to minimally invasive options that are intended to tailor therapy to individual patients.

DISCUSSION

Operative management of chronic pancreatitis often improves quality of life, and is associated with low rates of morbidity and mortality. The decision as to which procedure is optimal for each patient should be based on a combination of pathologic changes, prior interventions, and individual surgeon and center experience.

Comparison of Purification Solutions With Different Osmolality for Porcine Islet Purification

The osmolality of the purification solution is one of the most critical variables in human islet purification during islet isolation. We previously reported the effectiveness of a combined continuous density/osmolality gradient for the supplemental purification of human islets. We herein applied a combined continuous density/osmolality gradient for regular purification. The islets were purified with a continuous density gradient without osmolality preparation [continuous density/normal osmolality (CD/NO)] or continuous density/osmolality solution with osmolality preparation by 10× Hank's balanced salt solution (HBSS) [continuous density/continuous osmolality (CD/CO)]. The osmolality of the low-density solution was 400 mOsm/kg in both groups and that of the high-density solution was 410 mOsm/kg in the CD/NO group and 500 mOsm/kg in the CD/CO group. Unexpectedly, we noted no significant differences between the two solutions in terms of the islet yield, rate of viability and purity, score, stimulation index, or the attainability and suitability of posttransplantation normoglycemia. Despite reports that the endocrine and exocrine tissues of pancreata have distinct osmotic sensitivities and that high-osmolality solutions result in greater purification efficiency, the isolation and transplant outcomes did not markedly differ between the two purification solutions with different osmolalities in this study.

The Evaluation of Islet Purification Methods That Use Large Bottles to Create a Continuous Density Gradient

Islet purification is one of the most important steps of islet isolation for pancreatic islet transplantation. The most common method of islet purification is density gradient centrifugation using a COBE 2991 cell processor. However, this method can damage islets mechanically through its high shearing force. We recently reported that a new purification method using large plastic bottles effectively achieves a high yield of islets from the porcine pancreas. In the present study, we evaluated the methods of making a continuous density gradient. The gradient was produced with a gradient maker and two types of candy cane-shaped stainless steel pipes. One method was to use a "bent-tipped" stainless steel pipe and to load from a high-density solution to a low-density solution, uploading the stainless steel pipe. The other method was to use a regular stainless steel pipe and to load from a low-density solution to a high-density solution, leaving the stainless steel pipe in place. There were no significant differences between the two solutions in terms of the islet yield, rate of viability or purity, score, or the stimulation index after purification. Furthermore, there were no differences in the attainability or suitability of posttransplantation normoglycemia. Our study shows the equivalency of these two methods of islet purification.

Islet autotransplantation in a patient with hypercoagulable disorder

Total pancreatectomy and islet auto transplantation is a good option for chronic pancreatitis patients who suffer from significant pain, poor quality of life, and the potential of type 3C diabetes and pancreatic cancer. Portal vein thrombosis is the most feared complication of the surgery and chances are increased if the patient has a hypercoagulable disorder. We present a challenging case of islet auto transplantation from our institution. A 29-year-old woman with plasminogen activator inhibitor-4G/4G variant and a clinical history of venous thrombosis was successfully managed with a precise peri- and post-operative anticoagulation protocol. In this paper we discuss the anti-coagulation protocol for safely and successfully caring out islet transplantation and associated risks and benefits.

Reversal of Hypoglycemia Unawareness with a Single-donor, Marginal Dose Allogeneic Islet Transplantation in Korea: A Case Report

Pancreatic islet transplantation is a physiologically advantageous and minimally invasive procedure for the treatment of type 1 diabetes mellitus. Here, we describe the first reported case of successful allogeneic islet transplantation alone, using single-donor, marginal-dose islets in a Korean patient. A 59-yr-old patient with type 1 diabetes mellitus, who suffered from recurrent severe hypoglycemia, received 4,163 islet equivalents/kg from a single brain-death donor. Isolated islets were infused intraportally without any complications. The immunosuppressive regimen was based on the Edmonton protocol, but the maintenance dosage was reduced because of mucositis and leukopenia. Although insulin independence was not achieved, the patient showed stabilized blood glucose concentration, reduced insulin dosage and reversal of hypoglycemic unawareness, even with marginal dose of islets and reduced immunosuppressant. Islet transplantation may successfully improve endogenous insulin production and glycemic stability in subjects with type 1 diabetes mellitus.

The effect of time and temperature on viability and performance of Langerhans islets separated from Balb/c mouse after death

Background:

Tissue transplantation plays a pivotal role in the treatment of diseases. Pancreatic beta cell transplantation is the best way to obtain normal blood glucose in patients with diabetes type 1. However, it is not clear how long endocrine pancreas cells can be used for transplantation after the donor's death. The present study was conducted to analyze the performance and viability of pancreatic islet cells after death.

Materials and Methods:

Pancreas was separated from Balb/c mice at different times (0, 1, 4, 6, 12, and 24 h after death) at temperatures of 4°C and 23°C, and was cultured in Roswell_Park_Memorial_Institute (RPMI) 1640. Insulin shock, MTT assay, aldehyde fuchsin staining, dithizone staining, and florescence microscopy methods were applied to analyze the performance of beta cells, cell viability, islets’ diagnosis, islet cells’ diagnosis, and viable and necrotic cells diagnosis, respectively.

Results:

Islets of Langerhans and beta cells were diagnosed. By increasing the temperature and time, the viability and performance of beta cells decreased significantly (P < 0.05).

Conclusion:

The best condition for keeping the islets of Langerhans in terms of viability and performance is 4 h after death at temperature of 4°C.

Positive sterility cultures of transplant solutions during pancreatic islet autotransplantation are associated infrequently with clinical infection

BACKGROUND

Chronic pancreatitis is a painful and often debilitating disease. Total pancreatectomy with intra-portal islet autotransplantation (TP-IAT) is a treatment option that allows for pain relief and preservation of beta-cell mass, thereby minimizing the complication of diabetes mellitus. Cultures of harvested islets are often positive for bacteria, possibly due to frequent procedures prior to TP-IAT, such as endoscopic retrograde cholangiopancreatography (ERCP), stenting, or other operative drainage procedures. It is unclear if these positive cultures contribute to post-operative infections.

HYPOTHESIS

We hypothesized that positive cultures of transplant solutions will not be associated with increased infection risk.

METHODS

We reviewed retrospectively the sterility cultures from both the pancreas preservation solution used to transport the pancreas and the final islet preparation for intra-portal infusion of patients who underwent TP-IAT between April 2006 and November 2012. Two hundred fifty-one patients underwent total, near-total, or completion pancreatectomy with IAT and had complete sterility cultures. All patients received prophylactic peri-operative antibiotics. Patients with positive pancreas preservation solution or islet sterility cultures received further antibiotics for 5-7 d. Patients' medical records were reviewed for post-operative infections and causative organisms.

RESULTS

Of the 251 patients included, 151 (61%) had one or more positive bacterial cultures from the pancreas preservation solution or final islet product. Seventy-three of the 251 patients (29%) had an infectious complication. Thirty-four of the 73 (22%) patients with a post-operative infectious complication also had positive cultures. Only seven of 151 patients with positive cultures (4.7%) had an infectious complication caused by the same organism as that isolated from their pancreas or islet cell preparation.

CONCLUSIONS

In autologous islet preparations, isolation solutions frequently have positive cultures, but this finding is associated infrequently with clinical infection.

Islet size index as a predictor of outcomes in clinical islet autotransplantation

BACKGROUND

The islet size distribution in a preparation may contribute to islet transplant outcomes. At the same islet equivalent (IE) dose, larger islets may exhibit poorer therapeutic value and this may be because of oxygen diffusion limitations that worsen in proportion to islet size.

METHODS

To test this hypothesis, we studied the impact of islet size index (ISI) and other islet product characteristics on outcomes after islet autotransplant (IAT) in recipients receiving a marginal islet dose (2000-4999 IEs per kg body weight) from January 1, 2009 to June 11, 2012, at the University of Minnesota (n=58). ISI was defined as the number of IE divided by the number of islet particles (IPs) in a preparation; an ISI less than 1 indicates a mean islet diameter that is less than 150 μm. The primary post-IAT outcome was 6-month insulin use status.

RESULTS

Logistic regression analysis indicate that IPs/kg (P=0.001), IEs/kg (P=0.019), total IPs transplanted (P=0.040), and ISI (P=0.074) were most strongly correlated with the primary outcome. The ISI (mean±standard error) was lower for recipients achieving insulin independence at 6 months (0.71±0.05) versus those partially (0.83±0.05) or completely (1.00±0.07) insulin dependent. The combination of islet dose (expressed as units IPs/kg) and ISI exhibited a sensitivity of 75% and specificity of 74% in predicting insulin independence in this population of patients.

CONCLUSION

Islet autotransplant recipients of a marginal islet doses were more likely to achieve insulin independence when transplanted with a greater number of smaller islets.

Total pancreatectomy with islet cell auto-transplantation: update and outcomes from major centers

OPINION STATEMENT

Chronic pancreatitis is the result of irreversible damage to pancreatic acinar cells, and can result in debilitating chronic pain for patients. Treatment centers on pain relief, often with chronic narcotic use. Surgical therapy consists of both resection procedures to remove affected pancreatic parenchyma and drainage procedures to facilitate drainage of the main pancreatic duct. Total pancreatectomy historically was utilized in extreme cases due to the brittle glucose control that followed from the total loss of islet cells. Total pancreatectomy with islet cell auto-transplantation (TP-AIT) is gaining in popularity due to the maintenance of beta cell mass and the ability of patients to potentially be insulin independent post-operatively. TP-AIT is very helpful in the treatment of pain for patients with chronic pancreatitis. The overall majority of patients have an improvement in pain and quality-of-life scores. AIT also allows the majority of patients to have minimal insulin requirements post-operatively. With proper patient selection, these outcomes can be achieved.

D-Alanine in the islets of Langerhans of rat pancreas

Relatively high levels of D-alanine (D-Ala), an endogenous D-amino acid, have been found in the endocrine systems of several animals, especially in the anterior pituitary; however, its functional importance remains largely unknown. We observed D-Ala in islets of Langerhans isolated from rat pancreas in significantly higher levels than in the anterior/intermediate pituitary; specifically, 180±60 fmol D-Ala per islet (300±100 nmol/gislet), and 10±2.5 nmol/g of wet tissue in pituitary. Additionally, 12±5% of the free Ala in the islets was in the d form, almost an order of magnitude higher than the percentage of D-Ala found in the pituitary. Surprisingly, glucose stimulation of the islets resulted in D-Ala release of 0.6±0.5 fmol per islet. As D-Ala is stored in islets and released in response to changes in extracellular glucose, D-Ala may have a hormonal role.

Islet autotransplantation and total pancreatectomy

The goal of IAT is the preservation of beta-cell mass at the time of pancreatectomy. The majority of recipients have significant endogenous beta-cell function with positive blood C-peptide after surgery, even if only approximately one third achieve insulin independence. In appropriately selected patients, total pancreatectomy combined with IAT achieves relief of pain and improves quality of life with relatively easier-to-manage glycemic control and avoidance of hyper- and hypoglycemic episodes. Current research is focused on improving techniques of islet isolation and engraftment as well as long-term survival of autografted islets.

Comparison of Incubation Solutions Prior to the Purification of Porcine Islet Cells

For pancreatic islet transplantation, one of the most important steps of islet isolation is islet purification. The most common method of islet purification is density gradient centrifugation because there are differences in density between islets and acinar tissue. However, the density of islets/acinar tissue depends on several conditions, such as the incubation time before purification and the osmolality of the preincubation solution. In this study, we evaluated the impact of using two different preincubation solutions before purification. We used the University of Wisconsin (UW) solution and a new preservation solution (HN-1), which we recently developed. There were no significant differences between the two solutions in terms of the islet yield, rate of viability, and purity or stimulation index after purification. There were also no differences in the attainability and suitability of posttransplantation normoglycemia. Our study shows that the HN-1 solution is equivalent to the UW solution for preincubation before islet purification.

Proposed thresholds for pancreatic tissue volume for safe intraportal islet autotransplantation after total pancreatectomy

The simple question of how much tissue volume (TV) is really safe to infuse in total pancreatectomy-islet autotransplantation (TP-IAT) for chronic pancreatitis (CP) precipitated this analysis. We examined a large cohort of CP patients (n = 233) to determine major risk factors for elevated portal pressure (PP) during islet infusion, using bivariate and multivariate regression modeling. Rates of bleeding requiring operative intervention and portal venous thrombosis (PVT) were evaluated. The total TV per kilogram body weight infused intraportally was the best independent predictor of change in PP (ΔPP) (p < 0.0001; R(2) = 0.566). Rates of bleeding and PVT were 7.73% and 3.43%, respectively. Both TV/kg and ΔPP are associated with increased complication rates, although ΔPP appears to be more directly relevant. Receiver operating characteristic analysis identified an increased risk of PVT above a suggested cut-point of 26 cmH2O (area under the curve = 0.759), which was also dependent on age. This ΔPP threshold was more likely to be exceeded in cases where the total TV was >0.25 cm(3)/kg. Based on this analysis, we have recommended targeting a TV of <0.25 cm(3)/kg during islet manufacturing and to halt intraportal infusion, at least temporarily, if the ΔPP exceeds 25 cmH2O. These models can be used to guide islet manufacturing and clinical decision making to minimize risks in TP-IAT recipients.

No islets left behind: islet autotransplantation for surgery-induced diabetes

For patients with severe chronic pancreatitis refractory to medical interventions, total pancreatectomy can be considered to relieve the root cause of pain. The goal of a simultaneous islet autotransplant is to prevent or minimize the otherwise inevitable surgical diabetes. Islet autotransplant can successfully preserve some endogenous islet function in the majority of recipients, which mediates protection against brittle diabetes. Most maintain reasonably good glycemic control, while 30 %-40 % successfully discontinue insulin therapy. With islet autotransplants reaching a wider clinical audience, refinements in islet isolation techniques and strategies to protect islet grafts post-transplant may further improve the success of this procedure.

Total pancreatectomy and islet autotransplantation for chronic pancreatitis

BACKGROUND

Total pancreatectomy (TP) with intraportal islet autotransplantation (IAT) can relieve pain and preserve β-cell mass in patients with chronic pancreatitis (CP) when other therapies fail. We report on a >30-year single-center series.

STUDY DESIGN

Four hundred and nine patients (including 53 children, 5 to 18 years) with CP underwent TP-IAT from February 1977 to September 2011 (etiology: idiopathic, 41%; Sphincter of Oddi dysfunction/biliary, 9%; genetic, 14%; divisum, 17%; alcohol, 7%; and other, 12%; mean age was 35.3 years, 74% were female; 21% has earlier operations, including 9% Puestow procedure, 6% Whipple, 7% distal pancreatectomy, and 2% other). Islet function was classified as insulin independent for those on no insulin; partial, if known C-peptide positive or euglycemic on once-daily insulin; and insulin dependent if on standard basal-bolus diabetic regimen. A 36-item Short Form (SF-36) survey for quality of life was completed by patients before and in serial follow-up since 2007, with an integrated survey that was added in 2008.

RESULTS

Actuarial patient survival post TP-IAT was 96% in adults and 98% in children (1 year) and 89% and 98% (5 years). Complications requiring relaparotomy occurred in 15.9% and bleeding (9.5%) was the most common complication. IAT function was achieved in 90% (C-peptide >0.6 ng/mL). At 3 years, 30% were insulin independent (25% in adults, 55% in children) and 33% had partial function. Mean hemoglobin A1c was <7.0% in 82%. Earlier pancreas surgery lowered islet yield (2,712 vs 4,077/kg; p = 0.003). Islet yield (<2,500/kg [36%]; 2,501 to 5,000/kg [39%]; >5,000/kg [24%]) correlated with degree of function with insulin-independent rates at 3 years of 12%, 22%, and 72%, and rates of partial function 33%, 62%, and 24%. All patients had pain before TP-IAT and nearly all were on daily narcotics. After TP-IAT, 85% had pain improvement. By 2 years, 59% had ceased narcotics. All children were on narcotics before, 39% at follow-up; pain improved in 94%; and 67% became pain-free. In the SF-36 survey, there was significant improvement from baseline in all dimensions, including the Physical and Mental Component Summaries (p < 0.01), whether on narcotics or not.

CONCLUSIONS

TP can ameliorate pain and improve quality of life in otherwise refractory CP patients, even if narcotic withdrawal is delayed or incomplete because of earlier long-term use. IAT preserves meaningful islet function in most patients and substantial islet function in more than two thirds of patients, with insulin independence occurring in one quarter of adults and half the children.

Total pancreatectomy and islet autotransplantation for chronic pancreatitis

BACKGROUND

Total pancreatectomy (TP) with intraportal islet autotransplantation (IAT) can relieve pain and preserve β-cell mass in patients with chronic pancreatitis (CP) when other therapies fail. We report on a >30-year single-center series.

STUDY DESIGN

Four hundred and nine patients (including 53 children, 5 to 18 years) with CP underwent TP-IAT from February 1977 to September 2011 (etiology: idiopathic, 41%; Sphincter of Oddi dysfunction/biliary, 9%; genetic, 14%; divisum, 17%; alcohol, 7%; and other, 12%; mean age was 35.3 years, 74% were female; 21% has earlier operations, including 9% Puestow procedure, 6% Whipple, 7% distal pancreatectomy, and 2% other). Islet function was classified as insulin independent for those on no insulin; partial, if known C-peptide positive or euglycemic on once-daily insulin; and insulin dependent if on standard basal-bolus diabetic regimen. A 36-item Short Form (SF-36) survey for quality of life was completed by patients before and in serial follow-up since 2007, with an integrated survey that was added in 2008.

RESULTS

Actuarial patient survival post TP-IAT was 96% in adults and 98% in children (1 year) and 89% and 98% (5 years). Complications requiring relaparotomy occurred in 15.9% and bleeding (9.5%) was the most common complication. IAT function was achieved in 90% (C-peptide >0.6 ng/mL). At 3 years, 30% were insulin independent (25% in adults, 55% in children) and 33% had partial function. Mean hemoglobin A1c was <7.0% in 82%. Earlier pancreas surgery lowered islet yield (2,712 vs 4,077/kg; p = 0.003). Islet yield (<2,500/kg [36%]; 2,501 to 5,000/kg [39%]; >5,000/kg [24%]) correlated with degree of function with insulin-independent rates at 3 years of 12%, 22%, and 72%, and rates of partial function 33%, 62%, and 24%. All patients had pain before TP-IAT and nearly all were on daily narcotics. After TP-IAT, 85% had pain improvement. By 2 years, 59% had ceased narcotics. All children were on narcotics before, 39% at follow-up; pain improved in 94%; and 67% became pain-free. In the SF-36 survey, there was significant improvement from baseline in all dimensions, including the Physical and Mental Component Summaries (p < 0.01), whether on narcotics or not.

CONCLUSIONS

TP can ameliorate pain and improve quality of life in otherwise refractory CP patients, even if narcotic withdrawal is delayed or incomplete because of earlier long-term use. IAT preserves meaningful islet function in most patients and substantial islet function in more than two thirds of patients, with insulin independence occurring in one quarter of adults and half the children.

Impact of tissue volume and purification on clinical autologous islet transplantation for the treatment of chronic pancreatitis

Autologous islet transplantation after total pancreatectomy is an excellent treatment for painful chronic pancreatitis. Traditionally, islets have been isolated without purification; however, purification is applied when the tissue volume is large. Nevertheless, the impact of tissue volume and islet purification on clinical outcomes of autologous islet transplantation has not been well examined. We analyzed 27 cases of autologous islet transplantation performed from October 2006 to January 2011. After examining the relationship between tissue volume and portal pressure at various time points, we compared islet characteristics and clinical outcomes between cases with complications (complication group) and without (noncomplication group), as well as cases with purification (purification group) and without (nonpurification group). Tissue volume significantly correlated with maximum (R = 0.61), final (R = 0.53), and delta (i.e., difference between base and maximum; R = 0.71) portal pressure. The complication group had a significantly higher body mass index, tissue volume, islet yield, and portal pressure (maximum, final, delta), suggesting that complications were associated with high tissue volume and high portal pressure. Only one of four patients (25%) in the complication group became insulin free, whereas 11 of 23 patients (49%) in the noncomplication group became insulin free with smaller islet yields. The purification group had a higher islet yield and insulin independence rate but had similar final tissue volume, portal pressure, and complication rates compared with the nonpurification group. In conclusion, high tissue volume was associated with high portal pressure and complications in autologous islet transplantation. Islet purification effectively reduced tissue volume and had no negative impact on islet characteristics. Therefore, islet purification can reduce the risk of complications and may improve clinical outcome for autologous islet transplantation when tissue volume is large.

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.

Advances and challenges in islet transplantation: islet procurement rates and lessons learned from suboptimal islet transplantation

The initial step in successful islet transplantation is procurement of healthy donor islets. Given the limited number of donor pancreata selected for islet isolation and that islets from multiple donors are typically required to obtain insulin independence, it is critical to improve pancreas procurement rates and yield of islets for transplantation. Islets are delicate microorgans that are susceptible to apoptosis, hypoxia, and ischemia during isolation, culture, and the peritransplant period. Once the islets are engrafted, both prompt revascularization and protection from beta-cell death and graft rejection are key to secure long-term survival and function. To facilitate the engraftment of more robust islets suitable for combating the challenging isolation period and proinflammatory transplantation milieu, numerous approaches have been employed to prevent beta-cell dysfunction and death including immune modulation, prevention of apoptosis and hypoxia, as well as stimulation of growth factors, angiogenesis, and reinnervation. In addition to briefly discussing islet isolation procedures, procurement rates, and islet transplantation, the relevant literature pertaining to successful suboptimal islet transplantation is reviewed to provide insight into potential approaches to balance the limited supply of available donor islets.